Aug. 27, 2008 - load status and charging parameters such as track, to provide users with the best safety of the remaining time estimated

Aug. 22, 2008 - Battery of the five main parameters: the battery capacity, nominal voltage

1899, Waldmar Jungner in the open-type nickel-cadmium batteries, the first to use a nickel plate, almost at the same time, Thomas Edison invented the electric car for the nickel-iron battery. Unfortunately, because these alkaline batteries at the time of the plate material than other batteries for the village much more expensive materials, practical application has been greatly restricted.

     Later, Jungner the nickel-cadmium batteries after several important improvements, performance improved significantly. One of the most important improvement in 1932, scientists began in the nickel batteries in the use of the active substance. They will be active substances into the porous nickel plate, then nickel metal plate into crust. Nickel-cadmium battery development of another important milestone in the history of the 1947 seal of the successful development of nickel-cadmium batteries. In such a battery, the chemical reactions do not have to emit gases can be combined in the internal battery. Sealed nickel-cadmium battery successful development of the nickel-cadmium batteries on the application of greatly increased.

     Sealed nickel-cadmium battery high efficiency, long life cycle, the energy density, small size, light weight, compact, and does not require maintenance, in industrial and consumer products have been widely used.

     With the development of space technology, people have the power requirements of getting higher and higher. The mid-1970s, the United States has succeeded in the development power, light weight, long life, low-cost nickel-metal hydride batteries, and in 1978 succeeded in such batteries used in satellite navigation, nickel-hydrogen batteries and nickel-cadmium batteries with the volume of Than, the capacity can be doubled, but not the heavy metal cadmium pollution problems. Its work and nickel-cadmium battery voltage identical to working life are generally quite, but it has a good charge and have a discharge performance. In recent years, the nickel-metal hydride batteries worldwide attention, an endless stream of new technologies. Nickel-hydrogen battery has just come out, it is necessary to use high-pressure hydrogen storage containers, but people used to store metal hydride hydrogen, which made a low-voltage nickel-hydrogen batteries and even atmospheric pressure. 1992, the Japanese company Sanyo monthly capacity of 2 million nickel-hydrogen batteries. Currently has more than 20 domestic units to develop and produce nickel-hydrogen batteries, nickel-hydrogen batteries of domestic properties has reached the international advanced level.

Battery parameters

     Battery of the five main parameters: the battery capacity, nominal voltage, internal resistance, the discharge termination voltage and end-of-charge voltage. Battery capacity is usually used Ah (the) said, 1 Ah is in the 1 A discharge under the current one hour. Battery units within the number of active substances containing the decision to charge the battery unit volume and the content of active substances from the battery to use the material and size of a decision, therefore, usually battery size is, the higher capacity. Battery capacity and a parameter is related to the battery charge current. The battery charge current rate is usually used charging that C, C batteries for the rated capacity. For example, with 2 A current of 1 Ah batteries, charging rate is 2 C; Similarly, with 2 A current of 500 mAh battery charge rate is 4 C.

     Battery mint, are among the potential negative difference as the nominal battery voltage. Nominal voltage from the plate electrode potential of the electrolyte concentration and the internal decision. When the ambient temperature, the use of time and changes in working conditions, the output voltage of the battery unit slight changes, in addition, the output voltage batteries and battery power is left to a certain extent relations. Unit nickel-cadmium battery nominal voltage of about 1.3 V (but generally considered to be 1.25 V), nickel-hydrogen battery unit of nominal voltage of 1.25 V.

     The resistance of the battery plate in the decision-flow resistance and the resistance. In charge and discharge process, the resistance is the same plate, but the resistance will ion flow with the electrolyte concentration of charged ions and neutral change.

     Battery fully charged, a panel of active substances has reached saturation point, to continue charging, the battery voltage will not rise, then known as the voltage charge termination voltage. Nickel-cadmium battery of end-of-charge voltage of 1.75 ~ 1.8 V, nickel-hydrogen battery charge termination voltage of 1.5 V.

Table 1-1 nickel-cadmium battery discharge rate different from the termination voltage discharge

     Discharge termination of the battery voltage is allowed to discharge when the minimum voltage. If voltage is lower than the termination voltage discharge to discharge the battery, battery voltage at both ends will rapidly declining, a depth of discharge, so that a panel formed in the normal charge of the product when it difficult to resume, thus affecting the life of the battery. Discharge termination voltage and the rate on discharge. Nickel-cadmium battery voltage discharge and termination of the relationship between the discharge rate as listed in Table 1-1, nickel-hydrogen battery voltage discharge general provisions for the termination of 1 V.

Nickel-cadmium batteries principle

     Nickel-cadmium battery cathode materials for nickel hydroxide Asia-graphite and a mixture of negative material for the sponge-like cadmium powder and cadmium oxide powder, the electrolyte is usually sodium hydroxide or potassium hydroxide solution. When the temperature is high, the use of density of 1.17 ~ 1.19 (15 ¡æ) of sodium hydroxide solution. When the temperature is low, the use of density of 1.19 ~ 1.21 (15 ¡æ) of potassium hydroxide solution. -15 ¡æ in the following, the use of density of 1.25 ~ 1.27 (15 ¡æ) of potassium hydroxide solution. To take into account low-temperature performance and ability to maintain the charge, sealed nickel-cadmium batteries used density of 1.40 (15 ¡æ) of potassium hydroxide solution. In order to increase battery capacity and cycle life, usually in the electrolyte by adding a small amount of lithium hydroxide (about a litre of electrolyte and 15 ~ 20 g).

     Nickel-cadmium rechargeable batteries, the cathode active material into a plate of nickel hydroxide] [NiOOH, the negative electrode active material into a plate of metal cadmium, nickel-cadmium battery discharge, the board of cathode active material into nickel hydroxide Asia , The negative electrode active material into a plate of cadmium hydroxide.

1. Discharge in the process of electrochemical reaction

(1) negative reaction

     On the negative cadmium after the loss of two electronic into the price of cadmium-Cd2 +, and then immediately with the solution of the two hydroxide ion of OH-generation cadmium hydroxide Cd (OH) 2, deposition to the anode plate.

(2) positive reaction

     The board of cathode material is nickel hydroxide (NiOOH) crystal. For the price of nickel ions are three (Ni3 +), two each in the lattice of nickel ions can be obtained from the circuit outside the negative electrode to two electronic transfer, the price of generating two-2 Ni2 +. At the same time, the solution of every two water molecules to two ionizing hydrogen ions into the cathode plate, with lattice on the negative ions of oxygen combine the two, creating two hydroxide ion, and then with the lattice on the original two Hydroxide ions together, and the two second-generation nickel price of the two-nickel hydroxide crystals.

Will be more than the sum of the two, that is a nickel-cadmium battery discharge when the general reaction:

2. Recharging process in the chemical reaction

     Charging, the batteries will be positive and negative with the charger connected to the anode and cathode, and the internal battery discharge when exactly the opposite of the electrochemical reaction, that is, reduction in anode, cathode oxidation reactions.

(1) negative reaction

     Negative charge at the board of cadmium hydroxide, the first ionization ion and cadmium into hydrogen and oxygen ions, and ions from the outside of cadmium in electrical circuits to generate cadmium atom attached to the very board, and hydroxide ions into the solution to participate in positive reactions:

(2) positive reaction

     The role of outside power, the board of the cathode-nickel hydroxide lattice, the price of nickel ions two of the three lost a generation of electronic price of nickel ions, at the same time, two lattice hydroxide ions in the release of a hydrogen Ion, will remain in the lattice of oxygen anions, with the release of hydrogen ions in the solution of hydrogen and oxygen ions combine to form water molecules. Then, two three price of nickel ions and the two oxygen anions and the remaining two hydroxide ions combine to generate two nickel hydroxide crystals:

Will be more than the sum of the two, that is a nickel-cadmium rechargeable 40Y6799 batteries, the electrochemical reaction:

     At the end of rechargeable batteries, rechargeable batteries, will enable the current decomposition of water in the reaction, positive and negative board will be a large number of oxygen and hydrogen precipitation, the electrochemical reaction is as follows:

     From the above we can see that electrode reaction, to exclude Sodium hydroxide or potassium hydroxide is not directly involved in the response, since only conductive role. Reaction from the battery, charging water molecules generated in the process, in the course of discharging water consumption, so filling, in the course of discharge of electrolyte concentration in a small, which can not be detected density of charge and discharge level.

3. Terminal voltage

Adequate power, immediately disconnect the charging circuit, nickel-cadmium battery EMF up to around 1.5 V, but quickly fell to 1.31-1.36 V.

Nickel-cadmium battery terminal voltage with the charge and discharge process and changes can be under-said:

Filling Filling U = E + I charge R,

U-= E-- I-R,

     From the style, we can see that charging, the battery voltage discharge than when the high and the charge current is, the higher-voltage; discharge current is, the lower the voltage.

     When the nickel-cadmium battery to discharge current discharge standards, the average working voltage of 1.2 V. A discharge rate of 8 h, the 40Y6797 battery voltage dropped to 1.1 V, the battery-end, that is.

4. Capacity and capacity of the main factors affecting

     After the battery fully charged, to a certain discharge conditions, the requirement to release the termination voltage at the battery release of the total rated capacity as the battery capacity, with capacity Q discharge current and discharge time to express the product of that type are as follows:

Q = I t (Ah)

Nickel-cadmium battery capacity and the following factors:

¢Ù the number of active substances;

¢Ú discharge rate;

¢Û electrolyte.

     Discharge current direct impact on the termination voltage discharge. Termination of the required voltage discharge, discharge current is, the smaller the battery capacity.

     The use of different components of the electrolyte, the 40Y6795 battery capacity and life have a certain impact. Typically, in high-temperature environment, in order to improve battery capacity, often add a small amount of electrolytes in lithium hydroxide to form the mixed solution. Experimental proof: a litre of electrolyte added 15 ~ 20 g aquifer lithium hydroxide, at normal temperature, capacity can be increased by 4% to 5%, at 40 ¡æ, the capacity can be increased by 20%. However, the electrolyte lithium-ion over the content, not only increase the resistance to the electrolyte, but also to remain in the cathode board lithium-ion (Li +) slowly infiltrated the internal lattice of positive changes in the chemical have harmful effects .

     Electrolyte temperature on a greater impact on the capacity of the battery. This is because as the electrolyte temperature increases, the active substance of the plate chemical reaction also gradually improving.

     Electrolyte in the more harmful impurities, the smaller the battery capacity. The main harmful impurities are carbonate and sulfate. They can increase the resistance of electrolyte, when the low temperature and crystallization easy to plug the porous plate so that the battery capacity dropped significantly. In addition, the carbonate ion and also negative plates, cadmium carbonate attached to generate negative plates on the surface, thus leading to bad conductive to increase the resistance of the battery, the capacity decline.

5. Internal resistance

Nickel-cadmium batteries and the internal resistance of the electrolyte conductivity, structure and size of the plate, and electrolyte conductivity with the density and temperature. Battery electrolyte mainly by the internal resistance of the resistance decision. Potassium hydroxide and sodium hydroxide solution with the density of the resistance coefficient and variable. 18 ¡æ, potassium hydroxide solution of sodium hydroxide solution and the least resistance coefficient. Usually nickel-cadmium 40Y6793 batteries can be used under the resistance of computing:

6. Efficiency and life

In normal use conditions, the nickel-cadmium battery capacity ¦Ç Ah efficiency of 67% -75%, electric energy efficiency ¦Ç Wh 55% to 65%, cycle life of about 2000 times. ¦§ Ah capacity and efficiency of electric energy efficiency ¦Ç Wh formula is as follows:

(U-Charge and U should take the average voltage)

7. Memory effect

Nickel-cadmium batteries used in the process, if not all electricity End began to take charge, discharge, next time, we can not produce all the electricity. For example, nickel-cadmium batteries only produce 80 percent of the electricity after the start charging, fully charged, the batteries can only produce 80 percent of electricity consumption, a phenomenon called the memory effect.

End all-electric battery, is the crystallization of a small board. After the discharge of the batteries, nickel hydroxide Asia have not been completely turned into nickel hydroxide, the remaining nickel hydroxide Asia will be combined together to form larger crystals. Crystal larger nickel-cadmium battery is a main reason for the memory effect.

Nickel-metal hydride batteries works

     Nickel-metal hydride batteries and the same volume compared with the nickel-cadmium battery, the capacity to be doubled, charge and discharge cycle life expectancy is longer, and no memory effect. Nickel-hydrogen battery cathode active material for the NiOOH (discharge) and Ni (OH) 2 (charging), the negative plates active substances for H2 (discharge) and H2O (charging), with 30 percent of the electrolyte hydroxide Potassium solution, charge and discharge the electrochemical reaction is as follows:

     Seen from the equation: charging, negative precipitation hydrogen, stored in containers, from cathode-nickel hydroxide, a nickel hydroxide (NiOOH) and H2O; discharge when the hydrogen is consumed on the anode, cathode changed from nickel hydroxide Nickel hydroxide into Asia.

Excessive charging of the electrochemical reaction:

     From the formula that the 02K7052 battery charging excessive, the cathode plate precipitation oxygen, hydrogen precipitation negative plates. As a catalyst for the hydrogen electrode area, and hydrogen can readily spread to hydrogen electrode surface, therefore, hydrogen and oxygen in the battery can be easily combined to generate internal water so that the containers of gas pressure remains unchanged, this further compounded the Rates soon, so that the concentration of oxygen in the internal battery, no more than a few per thousand.

     Reaction from the above we can see that the response of nickel-hydrogen batteries and nickel-cadmium batteries similar, only negative charge and discharge process of product different from the reaction of the latter two can be seen, nickel-hydrogen batteries can also cause sealed structure . Nickel-metal hydride batteries used in multi-KOH electrolyte solution and to add a small amount of LiOH. Divide or use POROUS Vinylon non-woven fabrics such as nylon nonwoven. In order to prevent rechargeable batteries during the latter part of the internal pressure too high, battery equipped with anti-explosive device.

Of batteries

     Nickel-cadmium batteries characteristic curve as shown in Figure 1. When the constant current charge just to put End of battery power when a pressure drop due to internal resistance battery, battery voltage soon rise (A). Since then, the battery charge start, the battery voltage to a lower rate continued to rise. In this context (AB between), the electrochemical reaction to generate a certain rate of oxygen, the oxygen at the same time also with the same rate combined with hydrogen, therefore, the internal battery temperature and low gas pressure.

Figure 1 nickel-cadmium battery charging curve

     Battery charging process, the oxygen above the compound of oxygen, increased pressure within the battery. Battery * within the normal pressure of about 1 lb / 2 inches. The charge, according to charging rate, the battery internal pressure will soon increase to 100 pounds force / 2 inches or higher.

     Rechargeable batteries on the various methods, nickel-cadmium batteries, the gas is a key issue. Bubble gathered at the plate surface, will reduce the plate surface chemical reactions involved in the area and increase the resistance of the battery. When a rechargeable battery, the large amounts of gas, if not quickly compound, battery internal pressure will increase significantly, this will damage the 02K7055 battery. In addition, too much pressure, a sealed battery will open pores, so that the electrolyte Yisan. If the electrolyte repeatedly put through the stomata Yisan, the thick of the electrolyte increases, inter-plate transfer more difficult, increase the resistance of the battery, the capacity decline.

     After a certain period of time after (C), electrolyte begin to bubble, these bubbles gathered at the plate surface, the effective area to reduce the plate, so the impedance of the battery increase, the battery voltage start up faster. This is close to adequate electric signal.

     Adequate power, the battery charge is not converted to the current battery energy storage, but have a board of oxygen in the ultra-positive potential. Oxygen is due to electrolysis and the electrolyte, is not due to the reduction of cadmium hydroxide caused by cadmium. Potassium hydroxide and water in the composition of the electrolyte, hydrogen and oxygen ions into oxygen, water and free electrons, the reaction-to 4 OH-¡ú O2 ¡ü +2 H2O +4 e -

     Although the electrolyte of oxygen can quickly produce negative plates in the surface of the electrolyte in the compound, but the battery temperature still significantly higher. In addition because of the charge current used to generate oxygen, so the pressure within the 02K7053 battery increase.

     As the large number of hydrogen and oxygen ions from the rarely than in the cadmium hydroxide more easily in the decomposition of oxygen, the temperature inside the battery sharp rise, so that the battery voltage drops. So the battery voltage curve peak (D).

     Electrolyte, and the formation of oxygen is exothermic reaction, a rechargeable battery, (E), continuously produce oxygen, so that the battery temperature and pressure increased. If mandatory emission gases, will lead to reduced electrolyte, the battery capacity decline and damage the battery. If the gas can not be quickly discharged, the battery will be explosive.

     Use low-rate constant trickle charge, the battery will have a dendrite. These dendrite to the plate through the gap between the spread. In the proliferation of the more serious cases, these dendritic cells will cause some or all of short-circuit.

     The rechargeable nickel-metal hydride batteries and nickel-cadmium batteries of similar, charging them in the course of the voltage and temperature curve in Figure 1-2 and 1-3 as shown in Fig. We can see that the end-of-charge, nickel-cadmium battery voltage drop than the nickel-metal hydride batteries is much greater. When the battery capacity of the rated capacity of 80 percent previously, nickel-cadmium battery temperature rise slowly, when the battery capacity reached 90% after the nickel-cadmium batteries before the temperature rose rapidly. When fully charged 02K7053 battery basic, nickel-cadmium / nickel-hydrogen battery temperature rise rate is basically the same.

Charging process and the charging method

     Battery charging process can generally be classified into pre-charge, fast charge, charge up, the trickle charge four stages.

     In the long term or not the new batteries, used a fast start charging, it will affect the life of the battery. Therefore, the battery should be used on the current charge, the charge to meet certain conditions, known as the pre-charge at this stage.

     Fast charging is to use the current charge, the rapid restoration of battery power. Fast charge rate of 1 C above normal in the rapid charge from the battery capacity and charging rate decision.

     In order to avoid the charge, a small number of current rechargeable battery charger. Nickel-cadmium rechargeable batteries normal, acceptable C/10 or lower charge rate, this time to charge more than 10 h. A small current charging, the battery will not have too much gas, battery temperature will not be too high. As long as the battery charger received, the constant current low rate of the battery charger will be able to provide very small trickle charge current. Current use of small battery charging, the battery in the amount of heat generated can be naturally dispersed.

     Trickle chargers main problem is charging too slow, for example, the storage capacity of 1 Ah batteries, a rechargeable C/10 rate, the charging time to 10 h above. In addition, the rechargeable 02K6928 battery low rate of repeated charging, but also will produce dendrite. Most trickle chargers, all without any voltage or temperature feedback control and therefore can not guarantee sufficient battery power immediately after the shutdown charger.

     Rapid charging at constant current charging and charging the two pulse, constant current charging is a constant current of the current charge, the charge is the first pulse by pulse current of batteries. Then let the battery discharge, so cycle. Battery pulse amplitude great, a very narrow width. Usually discharge pulse amplitude of the pulse for charging three times around. Although the amplitude and pulse discharge capacity of the battery, but the charge current amplitude and the ratio remains unchanged, pulse charging, the charge current wave as shown in Figure 1-4.

     Charging process, the nickel-cadmium batteries in the nickel hydroxide reduced to sub-nickel hydroxide, cadmium hydroxide reduced to cadmium. In the course of the bubble, gathered on both sides of the plate, this will reduce the effective area of the plate, the plate so that the internal resistance increases. Since the effective area of plate smaller, filling in all of the time required to increase electricity consumption.

     Join the discharge pulse, the bubble left the anode plate with the board and the oxygen compound. This polarization process to reduce the cell's internal pressure, temperature and internal resistance. At the same time, filling most of the 02K7054 battery charge is converted to chemical energy, and will not change as a gas and heat.

     Charge and discharge pulse width of the plate choice should be able to guarantee restoration of the original crystal structure, thereby eliminating memory effect. Used to discharge polarization measures, can improve efficiency and allow charging high current fast charge

Jun. 20, 2008 - High-power lithium-ion battery

Until recently, applications for high current rate capabilities were reserved for nickel-cadmium and nickel-metal-hydride batteries. These applications include power tools and medical equipment. Much has changed in the fields of lithium-based batteries during the last few years and high current lithium-ion now claim similar or higher load capabilities to nickel-based system. These new-technology ThinkPad T60 batteries are expected to have a similar impact on high-power portable products as the introduction of lithium-ion had on the consumer electronics market in the 1990s.

In spite of its great popularity, the cobalt-based lithium-ion has some limitations. It is not very robust and cannot take a high charge and discharge currents. Trying to force a rapid charge or loading the battery with excess discharge current would overheat the pack and its safety would be jeopardized. The safety circuit of the cobalt-based battery is typically limited to a charge and discharge rate of about 1C. This means that a 2400mAh 18650 cell ThinkPad X60 can only be charged and discharged with a maximum current of 2.4A. Another drawback of the cobalt system is the increase of the internal resistance that occurs with cycling and aging. After 2-3 years of use, the pack often becomes unserviceable due to a high voltage drop under load that is caused by elevated internal resistance. This condition cannot be reversed. ThinkPad R60e

New cathode material opened the door for higher rate capability. Moving away form cobalt also helped in lowering manufacturing costs. In 1996, scientists succeeded in using lithium manganese oxide as a cathode material. This substance forms a three-dimensional spinel structure that provides improved ion flow on the electrode. High ion flow reflects in a lower internal resistance and hence higher loading capability. Unlike the cobalt-based lithium-ion ThinkPad R60, the resistance stays low with cycling and aging. The battery does age, however, and the overall service life is similar to that of the cobalt system. A further advantage of spinel is its inherent high stability. Spinel needs less in terms of safety circuit compared to the cobalt system.

Low internal cell resistance is the key to high rate capability. This characteristic benefits both in fast-charging and high-current discharging. A spinel-based lithium-ion ThinkPad T60p in an 18650 package can, for example, be discharged at currents of 20-30A with marginal heat buildup. One-second load pulses of twice the specified current are permissible. At continuous high load requirements, a heat build-up will occur and a cell temperature cannot exceed 80¡ãC. Beside power tools and medical instruments, the spinel-based lithium-ion is a candidate for hybrid cars. Manufacturing cost will need to be lowered and the service life prolonged before this ThinkPad Z61e battery system can be used for automotive propulsion applications.

The spinel battery has some disadvantages, however. One of the largest drawbacks is the lower capacity compared to the cobalt-based system. Spinel provides roughly 1200mAh in an 18650 package, about half that of the cobalt equivalent. In spite of this, spinel provides an energy density that is about 50% higher than that of a nickel-based equivalent.

Types of lithium-ion FRU 92P1139 batteries
Lithium-ion has not yet reached full maturity and the technology is continually improving. The anode in today's cells is made up of a graphite mixture and the cathode is a combination of lithium and other choice metals. It should be noted that all materials in a battery have a theoretical energy density. With lithium-ion, the anode is well optimized and little improvements can be gained in terms of design changes. The cathode, however, shows promise for further enhancements. Battery research is therefore focusing on the cathode material. Another part that has potential is the electrolyte. The electrolyte serves as a reaction medium between the anode and the cathode.

The battery industry is making incremental capacity gains of 8-10% per year. This trend is expected to continue. This, however, is a far cry from Moore's Law that specifies a doubling of transistors on a chip every 18 to 24 months. Translating this increase to a battery would mean a doubling of capacity every two years. Instead of two years, lithium-ion has doubled its energy capacity in 10 years.
Today's lithium-ion FRU 92P1137  comes in many "flavours" and the differences in the composition are mostly related to the cathode material. Table 1 below summarizes the most commonly used lithium-ion on the market today. For simplicity, we summarize the chemistries into four groupings, which are Cobalt, Manganese, NCM and Phosphate.FRU 92P1167

Table 1: Most common types of lithium-ion FRU 92P1133 batteries.

The cobalt-based lithium-ion appeared first in 1991, introduced by Sony. This battery chemistry gained quick acceptance because of its high energy density. Possibly due to lower energy density, spinel-based lithium-ion had a slower start. When introduced in 1996, the world demanded longer runtime above anything else. With the need for high current rate on many portable devices, spinel has now moved to the frontline and is in hot demand. The requirements are so great that manufacturers producing these batteries are unable to meet the demand. This is one of the reasons why so little advertising is done to promote this product. E-One Moli Energy (Canada) is a leading manufacturer of the spinel lithium-ion in cylindrical form. They are specializing in the 18650 and 26700 cell formats. Other major players of spinel-based lithium-ion FRU 92P1131 are Sanyo, Panasonic and Sony.

Sony is focusing on the nickel-cobalt manganese (NCM) version. The cathode incorporates cobalt, nickel and manganese in the crystal structure that forms a multi-metal oxide material to which lithium is added. The manufacturer offers a range of different products within this battery family, catering to users that either needs high energy density or high load capability. It should be noted that these two attributes could not be combined in one and the same package; there is a compromise between the two. Note that the NCM charges to 4.10V/cell, 100mV lower than cobalt and spinel. Charging this FRU 92P1129 battery chemistry to 4.20V/cell would provide higher capacities but the cycle life would be cut short. Instead of the customary 800 cycles achieved in a laboratory environment, the cycle count would be reduced to about 300.

The newest addition to the lithium-ion family is the A123 System in which nano-phosphate materials are added in the cathode. Although the manufacturer has not officially announced what metal is being used, it is widely believed to be iron. They claim to have the highest energy density of a commercially available lithium-ion FRU 92P1141 battery. The cell can be continuously discharged to 100% depth-of-discharge at 35C and endures discharge pulses as high as 100C. The phosphate-based system has a nominal voltage of about 3.25V/cell. The charge limit is 3.60V. This is far lower than the customary 4.20V/cell of the cobalt-based lithium-ion. Because of these lower voltages, the A123 System will need be charged with a special charger. Due to the anticipated strong demand, this cell is expected to be in short supply. A123 Systems was founded in 2001, the company is privately held and the major shareholders include Motorola, Qualcomm and MIT.ASM 92P1168

Confusion with voltages
For the last 10 years or so, the nominal voltage of lithium-ion was known to be 3.60V/cell. This was a rather handy figure because it made up for three nickel-based ASM 92P1140 batteries (1.2V/cell) connected in series. Using the higher cell voltages for lithium-ion reflects in better watt/hours readings on paper and poses a marketing advantage, however, the equipment manufacturer will continue assuming the cell to be 3.60V.

The nominal voltage of a lithium-ion 40Y6795 battery is calculated by taking a fully charged battery of about 4.20V, fully discharging it to about 3.00V at a rate of 0.5C while measuring the average voltage. Because of the lower internal resistance, the average voltage of a spinel system will be higher than that of the cobalt-based equivalent. Pure spinel has the lowest internal resistance and the nominal cell voltage is 3.80V. The exception again is the phosphate-based lithium-ion. This system deviates the furthest from the conventional lithium-ion system.

Prolonged ASM 92P1132 battery life through moderation
Batteries live longer if treated in a gentle manner. High charge voltages, excessive charge rate and extreme load conditions will have a negative effect and shorten the battery life. This also applies to high current rate lithium-ion batteries. The longevity is often a direct result of the environmental stresses applied. The following guidelines suggest how to prolong ASM 92P1130 battery life.

¡ì The time at which the battery stays at 4.20/cell should be as short as possible. Prolonged high voltage promotes corrosion, especially at elevated temperatures. Spinel is less sensitive to high voltage.
¡ì 3.92V/cell is the best upper voltage threshold for cobalt-based lithium-ion. Charging batteries to this voltage level has been shown to double cycle life. Lithium-ion systems for defense applications make use of the lower voltage threshold. The negative is reduced capacity.
¡ì The charge current of Li-ion should be moderate (0.5C for cobalt-based lithium-ion). The lower charge current reduces the time in which the cell resides at 4.20V. It should be noted that a 0.5C charge only adds marginally to the charge time over 1C because the topping charge will be shorter. A high current charge tends to push the voltage up and forces it into the voltage limit prematurely.
¡ì A depth of discharge to 80% or less poses less strain on the battery than a full 100% discharge. It's better to charge lithium-ion more often than letting it down too deeply. One does not need to worry about memory as was the case with nickel-cadmium ASM 92P1128.

Note: In respect to fast-charging and topping charge, the charge behavior of lithium-ion 40Y6799 is similar to lead acid. Here, the voltage threshold of 2.35V/cell during regular charge needs to be lowered to 2.27V/cell when the VRLA is on standby. Keeping the voltage at the high threshold would contribute to corrosion. A similar effect occurs with lithium-ion.
Not only does a lithium-ion battery live longer with a slower charge rate, high discharge rates also contribute the extra wear and tear. Figure 1 shows the cycle life as a function of charge and discharge rates. Observe the good laboratory performance if the battery is charged and discharged at 1C. (A 0.5C charge and discharge would further improve this rating.)

Figure 1: Longevity of lithium-ion as a function of charge and discharge rates. A moderate charge and discharge puts less stress on the battery, resulting in a longer cycle life.

Battery experts agree that the longevity of lithium-ion is shortened by FRU 92P1127 other factors than charge and discharge rates alone. Elevated temperature while the battery is fully charged is one such element that shortens service life. Even though incremental improvements can be achieved with careful use of the battery, our environment and the services required are not always conducive to achieve optimal battery life. In this respect, the battery behaves much like us humans - we cannot always live a life that is favorable of achieving a maximum life span.40Y6797

Jun. 20, 2008 - Will Lithium-Ion batteries power the new millennium?(2)

Charging the Li-ion battery

The Li-ion charger is a voltage-limiting device and is similar to the lead acid 92P1075 battery charger. The main differences of the Li-ion charger are higher voltage per cell, tighter voltage tolerance and the absence of trickle or float charge at full charge. 92P1071,92P1060,92P1011,92P1087

Whereas the VRLA offers some flexibility in terms of voltage cut off, the manufacturers of Li-ion cells are very strict about the voltage choice. When first introduced, the charge voltage limit of the graphite system was 4.10 volts per cell. Although higher voltages deliver increased energy density, cell oxidation severely limited the service life in the early graphite cells if charged above the 4.10V/cell threshold. This effect has now been solved with chemical additives and most new Li-ion cells are now set to 4.20V. The tolerance on all Li-ion 92P1075 batteries is a tight +/- 0.05 volts per cell.

The charge time of all Li-ion 92P1071 batteries is about 3 hours at a 1C initial charge current. The battery remains cool during charge. Full charge is attained after the voltage reaches the upper voltage threshold and the current drops and levels off at about 3% of its nominal rating, or about 0.03C. 08K8214

Increasing the charge current on a Li-ion charger does not shorten the charge time by much. Although the voltage peak is reached quicker with higher current, the topping charge will take longer. Figure 3 shows the voltage and current signature of a charger as the Li-ion cell 08K8195 passes through stage one and two.

Figure 3:  Charge stages of a Li-ion 08K8193 Battery.
Increasing the charge current on a Li‑ion charger does not shorten the charge time by much. Although the voltage peak is reached quicker with higher current, the topping charge will take longer.

Claims of fast charging a Li-ion 08K8192 battery in one hour or less usually results in lower charge levels. Such a charger simply eliminates stage two and goes directly into ?I>ready?/I> once the voltage threshold is reached at the end of stage one. The charge level at this point is about 70%. The topping charge typically takes twice as long as the initial charge.

No trickle charge is applied because the Li-ion 92P1101 is unable to absorb overcharge. Trickle charge could cause plating of metallic lithium, a condition that makes the cell unstable. Instead, a brief topping charge is applied to compensate for the small amount of self-discharge the FRU 92P1069 battery and its protective circuit consume.

Depending on the charger and the self-discharge of the 08K8196 battery, a topping charge may be implemented once every 500 hours or 20 days. Typically, the charge kicks in when the open terminal voltage drops to 4.05 volts per cell and turns off when it reaches 4.20V/cell.

Protection circuit

Commercial Li-ion 92P1102 battery packs contain redundant protection devices to assure safety under all circumstances. Typically, an FET opens if the charge voltage of any cell reaches 4.30V, and a fuse activates if the cell temperature approaches 90°C (194°F). In addition, a pressure switch in each cell permanently interrupts the charge current if a safe pressure threshold is exceeded, and internal voltage control circuits cut off the battery at low and high voltage points. Exceptions are made to prismatic and cylindrical spinel packs containing one or two cells only.

The Li-ion is typically discharged to 3 volts per cell. The lowest ‘low-voltage?power cut-off is 2.5V/cell. During prolonged storage, however, a discharge below this voltage level is possible. Manufacturers recommend a ‘trickle?charge to raise such a battery gradually back up into the ‘acceptable?voltage window. Not all chargers are designed to apply a charge once a Li-ion 92P1077 battery has dipped below 2.5V/cell. 

Some batteries feature an ultra-low voltage cutoff that permanently disconnects the pack if a cell dips below 1.5 volts. This precaution is done to prohibit recharge if a battery has dwelled in an illegal voltage state. A deep discharge causes copper plating, which can lead to short circuit in the cell.

Most manufactures do not sell the Li-ion cells by themselves but make them available in a 92P1061 battery pack, complete with protection circuit. This precaution is understandable when considering the danger of explosion and fire if the battery is charged and discharged beyond its safe limits. 92P1073

A major concern arises if static electricity or a faulty charger has managed to destroy the battery’s protection circuit. Such damage often causes the solid-state switches to fuse to a permanent ON position without the user’s knowledge. A battery with a faulty protection circuit may function normally but does not provide the required safely. If charged beyond safe voltage limits with a poorly designed accessory charger, the battery may heat up, then bulge and in some cases vent with flame. Shorting such a battery can also be hazardous. 08K8201

Analyzers for the Lithium Ion 08K8199 batteries

In the past, battery analyzers were used to restore batteries affected by ‘memory? With today’s nickel-free batteries, memory is no longer a problem and the emphasis of an analyzer is shifting to battery performance verification, quality control and quick-test.

Conventional wisdom says that a new 08K8198 battery always performs flawlessly. Yet many users have learned that a battery fresh from the shrink-wrap does not always meet the manufacturer's specifications. With a battery analyzer, all incoming batteries can be checked as part of a quality control procedure. In addition, warranty claims can be made if the capacity drops below the specified level at the end of the warranty period.

A typical life of a Li-ion is 300-500 discharge/charge cycles or two years from time of manufacturing. The loss of battery capacity occurs gradually and often without the knowledge of the user. Although fully charged, the battery eventually regresses to a point where it may hold less than half of its original capacity. The function of the battery analyzer is to identify these weak batteries and “weed?them out.08K8197

A battery analyzer can also be used to troubleshoot the cause of short runtimes. The charger may not provide a full charge or the portable device may draw more current than expected. Many of today’s battery analyzers can simulate the load signature of a digital device and verify the runtime based on the available battery capacity.

An important feature of modern FRU 08K8193 battery analyzers is its ability to read the internal battery resistance, a test that only takes a few seconds to complet. As part of natural aging, the internal resistance of a Li-ion gradually increases due to cell oxidation. The higher the resistance, the less energy the battery can deliver.

To utilize the OhmTest as a battery validation, it is essential to obtain a reference reading of a good battery with known performance. Because each battery type may be different, a reference reading will be required for each model.

A more reliable method of measuring the state-of-health of a battery is through quick-test methods. Cadex has developed a system that uses an inference algorithm to test ThinkPad R50e battery capacities. The Quicktest algorithm is made battery specific by using a trend-learning algorithm that resembles the thinking process of the human brain.

The Cadex Quicktest can be performed with a charge level of between 20 and 90 percent. If the battery is insufficiently charged, or has too high a charge, the analyzer automatically applies the appropriate charge or discharge to bring the battery within testing range. Within this range, different charge levels do not affect the readings. The test lasts about two minutes and supports Li-ion/Polymer, NiMH and NiCd ThinkPad R50 batteries.

The Cadex quick test is added to the Cadex 7200 and 7400 battery analyzers. These platforms feature interchangeable battery adapters that contain the battery configuration codes and matrix for the quick test.

Summary

The Li-ion receives good grades in performance and reliability. Supply shortages have eased and prices have become competitive with nickel-based equivalents. As a result, more portable equipment is being fitted with the Li-ion ThinkPad T43 battery.

The Li-ion has found a strong market niche with portable devices demanding small form factor. The most popular uses are mobile phones and laptop computers. Because of the aging aspect, the Li-ion is most suitable for applications with a hectic user pattern. Where the Li-ion falls short is on high current applications, such as power tools, heart defibrillators and two-way radios for public safety.

Another field where the Li-ion has proven less favorable is in applications that require only occasional battery use. On a laptop that is mostly powered by AC, for example, the Li-ion ThinkPad T40 battery ages over time and the full benefit of the battery cannot be realized. High heat levels inside most laptops also cause the Li-ion to age prematurely. Field tests have revealed, however, that Li-ion is less affected by heat than NiMH.

The Lithium Ion Polymer systems are struggling to meet and surpass the performance of the Li-ion battery. High energy cost ratio limits the Li-ion Polymer to small portable devices, such as mobile phones. It is expected that once mass-produced, the Li-ion Polymer will be lower priced than the Li-ion because of simpler packaging.

Jun. 20, 2008 - Will Lithium-Ion batteries power the new millennium?(1)

For many years, the Nickel Cadmium (NiCd) was the only suitable Apple laptop battery  for portable applications such as wireless communications and mobile computing. In 1990, the Nickel Metal Hydride (NiMH) and Lithium Ion (Li-ion) emerged, offering higher capacities. Both chemistries fought nose to nose, each claiming better performance and smaller sizes.

Which chemistry will be the true winner and what system will pave the way in the new millennium? The vote is for Li-ion, especially for portables with a small form factor.

The Li-ion is a low maintenance battery, an advantage that no other chemistry can claim. There is no memory and no scheduled cycling is required to prolong the battery’s life. In addition to high energy density and lightweight, the self-discharge is less than half compared to the NiCd and NiMH, making the Li-ion well suited for modern fuel gauge applications.

On the negative, the Li-ion is fragile and requires a protection circuit to maintain safe operation. The load current is moderate and charging must be done according to strict standards. In addition, the Li-ion is subject to aging, whether used or not.

History

Pioneering work for the lithium Apple A1078 battery  began in 1912 by G. N. Lewis but it was not until the early 1970’s when the first non-rechargeable lithium batteries became commercially available. Attempts to develop rechargeable lithium batteries followed in the eighties, but failed due to safety problems.

Lithium is the lightest of all metals, has the greatest electrochemical potential and provides the largest energy content. Rechargeable Apple A1148 battery using lithium metal as the negative electrodes (anode) are capable of providing both high voltage and excellent capacity, resulting in an extraordinary high energy density.

After much research on rechargeable Lithium batteries during the eighties, it was found that cycling alters the lithium electrode, thereby reducing its thermal stability and causing potential thermal run-away. If this occurs, the cell temperature quickly approaches melting point of the lithium, which results in a violent reaction. A large quantity of rechargeable lithium batteries sent to Japan had to be recalled in 1991 after a battery in a cellular phone released hot gases and inflicted burns to a man’s face.

Because of the inherent instability of lithium metal, especially during charging, research shifted to a non-metallic lithium Apple M8244 battery using lithium ions. Although slightly lower in energy density than lithium metal, the Li‑ion is safe, provided certain precautions are met when charging and discharging. In 1991, the Sony Corporation commercialized the first Li‑ion battery. Other manufacturers followed suit. Today, the Li‑ion is the fastest growing and most promising battery chemistry.

Li-ion versions

There are several types of Li-ion Apple M7426 battery that have emerged. Sony’s original version used coke as negative electrode (anode). Since 1997, most Li-ion, including Sony’s, has shifted to graphite. This electrode provides a flatter discharge voltage curve than coke and offers a sharp knee bend, followed by a rapid voltage drop before the discharge cut off (see Figure 1). As a result, the useful energy of the graphite system can be retrieved by discharging only to 3.0 volts per cell, whereas Sony’s coke version must be discharged to 2.5 volts to get the same performance.

Figure 1:  Li‑ion discharge characteristics.
The graphite Li-ion only needs to discharge to 3.0V/cell Apple M6091 battery, whereas the coke version must be discharged to 2.5V/cell to achieve similar performance.

For the positive electrode (cathode), two distinct chemistries have emerged. They are cobalt and manganese, also know as spinel. Whereas the cobalt has been in use longer, spinel is inherently safer and more forgiving if abused. Protection circuits can be simplified or even eliminated. Small prismatic spinel packs for mobile phones may only include a thermal fuse and temperature sensor. In addition to the added safety, the raw material cost for manganese is lower than cobalt.

As a trade-off, the spinel offers a slightly lower energy density, suffers capacity loss at temperature above 40ºC and ages quicker than cobalt. Figure 2 compares the advantages and disadvantages of the two chemistries IBM ThinkPad T43 battery .

	Cobalt	Manganese (Spinel)
Energy density (Wh/kg)	140 1	120 1
Safety	On overcharge, the cobalt electrode provides extra lithium, which can form into metallic lithium, causing a potential safety risk if not protected by a safety circuit.	On overcharge, the manganese electrode runs out of lithium causing the cell only to get warm. Safety circuits can be eliminated for small 1 and 2 cell packs.
Temperature	Wide temperature range. Best suited for operation at elevated temperature.	Capacity loss above +40°C. Not as durable at higher temperatures.
Aging	Short-term storage possible. Impedance increases with age. Newer versions offer longer storage.	Slightly less than cobalt. Impedance changes little over the life of the cell. Due to continuous improvements, storage time is difficult to predict.92P1087
Life Expectancy	300 cycles, 50% capacity at 500 cycles.92P1089	May be shorter than cobalt.
Cost	Raw material relatively high; protection circuit adds to costs.	Raw material 30% lower than cobalt. Cost advantage on simplified protection circuit.

Figure 2:  Comparison of Cobalt and Manganese as positive electrodes.
IBM ThinkPad T41 battery Manganese is inherently safer and more forgiving if abused but offers a slightly lower energy density. Manganese suffers capacity loss at temperature above 40°C and ages quicker than cobalt.

¹ Based on present generation 18650 cells. The energy density tend to be lower for prismatic cells, 92P1091

Chemicals and additives help to balance the critical trade-off between high energy density, long storage time, extended cycle life and safety. High energy densities can be achieved with relative ease IBM ThinkPad T40 battery . For example, adding more nickel in lieu of cobalt increases the ampere/hours rating and lowers the manufacturing cost but makes the cell less safe. While a start-up company may focus on high energy density to gain quick market acceptance, safety, cycle life and storage may be compromised. Reputable manufacturers IBM FRU 08K8214 battery, such as Sony, Panasonic, Sanyo and Moli place high importance on safety.

Li-ion cells cause less harm when disposed than lead or cadmium based batteries. Among the Li-ion battery family, the spinel is the friendliest in terms of disposal FRU 08K8193

Jun. 19, 2008 - Broken Power Connector on a 2002 Dell Laptop

Re-soldering the Broken Power Connector on a 2002 Dell Laptop
So I made this page because I keep hearing about these loose Compaq Presario 700 battery connectors. The power plugs seem to be a common problem, and they are not impossible to fix. Here is my success story, I hope you find it to be a useful reference.

Compaq Presario 700 battery  charge light would flicker, eventually it did not work at all. The laptop was not getting power. Eventually the Compaq laptop battery ran out of power and was unusable.

Further Investigation:
We disassembled the laptop according to Dell's directions, which they kindly provide online. We wanted to remove the mainboard to examine it. There were some pieces we had to really wiggle to get to come apart. Also, they say to remove the RAM DIMMS and the CPU and heatsink, but we left those on with no problem.

Below, we discovered that at the point where the power connector was soldered to the bottom of the mainboard, one of the connections looked somewhat funny and blackened. This is the "bad solder joint" below.

I used my multimeter to measure the resistance from each pin inside the power plug, to the corresponding pin sticking through the circuit board. (About 0.1 Ohms each). However, that was really just measuring two ends of the same piece of metal, since it goes all the way through. Examining the suspicious-looking bad connection, I noticed an obvious circuit trace going to a nearby component. Using it's lead as a test point (see image above), I meansured the resistance from the connector plug pin. 4.9 Ohms! This is much higher than a good connection should be.

Repairing the bad connection ompaq Evo N600C battery , Compaq Evo N610C battery , Compaq Evo N620C battery
To fix it, I got out my grounded micro-electronics soldering iron. To provide a better connection, I decided to expose some of the circuit trace by scraping off the green coating with the edge of a screwdriver. Below, you can see the bit of extra copper showing next to the lead.

Next, I used the soldering iron to heat up the pin and the circuit lead at the connection, and then added solder, per good soldering technique. It turns out that my soldering iron was pretty wimpy and did not do a good job on the first try. (Something like 50 Ohms on the meter now!) On a second attempt, I was more patient, and used more solder. (Note, it is normal and desireable for some solder to get ****ed into the pin's hole in the board.) Finally, my connection was about 0.1 Ohms on the multimeter. Compaq Armada M700 battery ,Compaq Evo N1000C battery

We reassembled the laptop, and voila! It worked!

Jun. 19, 2008 - Fixing Laptop Power Problems

AC power  dell laptop battery dell 1691P battery adapter
How the AC adapter works
The most common type of AC power dell 75UYF battery dell 8N544 batteryadapter involves a small box, with one wire to go to the computer and another wire to go to the wall. There is usually an LED light on it, to tell you that it is on. (Is it lit on yours?) By the way, Apple notebook power adapters often have an LED that is actually built into the side of the computer, not into the adapter box, so obviously it won't light up when it's not connected to the computer.

The power Dell Latitude D500 battery  adapter box does several things. It lowers the voltage from the wall's 120 volts AC to typically 19 volts DC (it will be labeled with the exact voltage). It includes some power noise filtering. It often includes an automatic circuit breaker or overload detection. If this gets tripped, you can generally reset it if you unplug it from everything for a few minutes.

You can measure the voltages on your AC adapter with a multimeter. When it is unplugged from the computer but still plugged in to the wall, it is normal to find that the voltage may be 1 to 3 volts higher than the printed output rating.

Troubleshooting: AC Dell Inspiron 500m battery Power adapter LED is off when you plug the adapter into the wall but not into the computer
Has it been overloaded? Is the power strip turned on / is the outlet working? Is the cord from the adapter to the wall fully plugged in on both ends (try wiggling)? Your adapter may be fried- try borrowing an indentical adapter from a friend and seeing if that one will work in it's place (but do not plug it in to your computer, or you might fry your friend's adapter). dell Inspiron 9300 battery dell Inspiron 6000 battery

Troubleshooting: Check output voltages with a volt meter/multimeter
For those of you with circular connectors, your task is easy. Measure the voltage between the inside and the outside. A diagram on the HP F2019A battery adapter's label will tell you which should be positive and negative

For those of you with the 3-pin HP F2024A battery power connectors, I don't have a diagram for you yet, sorry. If you try measuring each of the three possible pairs of pins, you should get 20 volts between one of the pairs.

Power distribution inside the laptop
How laptop dell Inspiron 700m battery dell Inspiron 5100 battery power distribution works
 Okay, the power comes into the plug on the back of the computer. This connects it to metal traces inside the mainboard of the computer. These will be connected to voltage regulators which often output 5 volts, 12 volts, 3.3 volts, and the CPU voltage; they sometimes look like the image at right.

These will be connected to cylindrical capacitors distributed throughout the mainboard. Capacitors act like tiny, fast HP DP390A , supplying extra power where needed to maintain a steady voltage during high demand.

Finally, power goes to all the devices that need it.

Power for the LCD display is usually done seperately. Generally, LCD backlights require high voltage to operate. A component that might be called a power inverter will step the voltage up to what is needed for the backlight. Sometimes this inverter is a discrete and replacable component, and sometimes just a chip on your mainboard. It is also involved in the brightness control.dell Inspiron 8200 battery dell Inspiron 8100 battery

The battery is an important part. It supplys power to the input-side of the voltage regulators, just like the power from the AC adapter. Additionally, there is a charging circuit, which uses the power from the AC adapter prior to the voltage regulators, to charge the battery. (By the way, this is why the HP Pavilion DV1000 battery voltage is always rated higher than the battery's rated volatge-- you need higher voltage for charging.)

There is a separate page exclusively for HP F2019 battery  Problems.

Short circuits
Anywhere in your laptop, physical or electrical damage can cause a short circuit. A short circuit will consume all available power, causing your laptop to not turn on. If your power adapter LED comes on when you plug it into the wall, but then goes off when you plug in the HP Pavilion ZD7000 battery , you probably have a short circuit.

Troubleshooting short circuits
An ohm-meter / multimeter will read less than ~3 ohms when you measure the resistance between sides of power going into a short circuit. When measureing between then power pins going into the back of your computer, consider the 2 pins where you expect voltage to be applied by the AC adapter. If the resistance indicates a short circuit, this is bad.dell Inspiron 4000 battery dell Inspiron 600m battery

A common trick to help isolate possible problems is to try to removing anything that might be a short circuit. Take out the battery, the hard drive, the DVD/CD drive, the floppy drive, PCMCIA cards, USB devices, miniPCI cards. See if the computer will then turn on.

You might have luck with a thermal imager to find a hot spot caused by the short circuit.

Spilled liquid
Laptops exposed to small amounts of spilled liquid are repairable in some cases. Liquid can cause the following types of damage:

Short circuit due to wet liquid dell Latitude D500 battery dell Latitude D600 battery
Short circuit due to dried liquid residue
Corrosion (especially bad with soda such as Coke or Pepsi)
Electronic components damanged by above short circuits
Immediately when a spill occurs, you typically want to turn off the laptop, turn the laptop upside down (so the liquid goes out the same way it came in), remove the power and HP F2299A battery, and allow to dry at least overnight.

To remove dried liquid residue: Try removing the keyboard and cleaning any components that have dried liquid, by using distilled water and Q-tips.

Computer turns off randomly
Your computer can turn off due to: power overload in the HP laptop battery, overheated processor / clogged fan, overheated battery, pushing the power button, Windows telling it to, the BIOS telling it to, loose wires , or intermittent short circuits.

The most common problem is cooling. Try going somewhere air conditioned. Notice if the fan is broken or clogged with dust.

Web links
Laptop Battery Problems
Re-soldering a loose power connector
Unclogging an HP heat sink fan
Dell's Power Troubleshooting Guide
Repair4Laptop: Fixing Compaq laptop battery
Buy replacement power connector plug hardware
Story: Finding a Short Circuit
This laptop (HP zt1250) was used for 2.5 years. At 1.5 years it began running the fan constantly and would occasionally shutdown. At 2 years an external desk fan was required while burning CDs. At 2.5 years the laptop external power supply indicator light dimmed when the plug was inserted and was bright when the plug was removed. An electrical short had developed somewhere inside the laptop. The laptop would no longer run off Compaq Armada M700 battery.

The small charge left in one battery confirmed that the rest of the laptop was functioning.

Disassembly of the laptop revealed large accumulation of lint on the cooling fins of the heat pipe. See photograph. The cooling fan had slowly but surely suctioned lint and dust from the users bedroom, some of which was unable to pass between the cooling fins. Over time a huge blockage developed.dell Latitude D800 battery dell Latitude CPi battery

Removal of the lint did not remove the suspected electrical short. Further disassembly revealed a bad solder joint on the plus + pin of the power connector. Resoldering did not help. Further inspection did not reveal any abnormalities in the connector or surrounding printed circuit board. A shorted resistor, capacitor, or diode was now suspected but without schematics it was impossible to proceed.

The local fire department carries a thermal imager camera to see heat through smoke and walls. The camera was used to observe the circuit board while power was applied. The area near the power connector immediately began to show heat - thus confirming the connector or circuit card traces as the location of the electrical short..dell Latitude CPX battery dell Latitude C600 battery

Dissection of the connector did not reveal the short. I still measured zero ohms resistance from the plus side to the minus side. Removal of the plus connector pin and resoldering of a small wire in its place somehow cleared the short.Compaq Presario R3000 battery

The laptop works fine but I am disappointed not to know the exact source of the problem. The circuit board is likely a multi-layer board. One can see the top and bottom outer layers of copper foil on fiberglass epoxy board, and see shadows of the inner layer . Surface mount components attach to the surface, through-hole components pass from top to bottom through a hole drilled through. The inner layer ground plane should not get too close to this drilled hole. The "leg" of the +19VDC power connector passed through - one cannot observe what may have happened in that hole. dell Latitude C640 battery dell Latitude C840 battery dell Inspiron 8000 battery

Jun. 19, 2008 - Laptop Battery Problems

Laptop batteries can be one of the most frustrating parts of an older laptop. They only last 15 minutes, or maybe only 2 seconds, perhaps explode, etc. I created this site to try to document and analyze these problems.

How Dell Inspiron 6000 battery work
The battery consists of a plastic outer case, metal electrical contacts, an inner metal case filled with a chemical and special electrical contacts called electrodes, and lastly, perhaps some control circuitry.

Note that the actual charging circuit is usually part of the laptop mainboard.

Battery chemistry
• Lithium Ion (LIon)
• Nickel Metal Hydride (NiMH)
• Others...

Control circuitry
Different Dell Inspiron 630m battery may have none, some, or all of these circuits.

Overheat protection: A themal sensor and circuit cuts off charging and/or usage if the battery gets too hot.

Over-current / short-circuit protection: Like a circuit breaker, if the current is too high this will cut off the electricity coming from the battery to prevent explosion or fire.

Over-discharge protection: Certain battery Dell Inspiron 640m battery, such as Lithium Ion, will break down if the battery gets discharged below a certain point. This circuit cuts off usage just before this point is reached.

Status meter / battery tester: Many modern battery have a button you can push, and a meter of LEDs will show you how charged the battery is.

Reconditioning
Sometimes, battery performance can be improved through a process called reconditioning. This is usually a special pattern of charges and discharges designed to get the chemicals back to their original state. I suppose shaking might also be involved, as certain substances may build up near the electrodes inside.

Case Studies & Anecdotes
Gataway Solo 5300
Once fully charged, the charging circuit will not reactivate until after you have used the laptop under battery power. However, the battery slowly drains itself over time. The result is that if you have had the laptop plugged in to the AC for too long, the result will be a dead battery. The solution? Unplug the laptop from the AC for just a minute, and then reconnect. The battery will recharge.

Additionally, when using the Dell Latitude D820 battery, the power level detected by Windows when the computer first comes on sometimes is very low, such as 5%, causing Windows to automatically go back into standby. However, by turning it on again, you discover that now the battery is almost fully changed.

Dell Latitude D620 battery
By the end of the first year of use, the battery charge ended up only being good enough for 30 seconds of operation. :-/ Warranty service would have been a good idea

Jun. 19, 2008 - How to charge your new replacement laptop battery?

How to charge your new replacement laptop battery?

Your new Dell Inspiron 6000 battery comes in a discharged condition and must be charged before use (refer to your computer manual for charging instructions). Upon initial use (or after a prolonged storage period) the battery may require two to three charge/discharge cycles before achieving maximum capacity.

When charging the Dell Inspiron 640m battery , Dell Inspiron 630m battery for the first time your computer may indicate that charging is complete after just 10 or 15 minutes. This is a normal phenomenon with rechargeable batteries. Simply remove the battery from the computer and repeat the charging procedure.

It is important to condition (fully discharge and then fully charge) the Dell Latitude D820 battery every two to three weeks. Failure to do so may significantly shorten the battery's life (this does not apply to Li-ion batteries, which do not require conditioning). To discharge, simply run your device under the battery's power until it shuts down or until you get a low Dell Latitude D620 battery warning. Then recharge the battery as instructed in your user's manual.

Jun. 19, 2008 - A laptop is a personal computer which is portable

A laptop is a personal computer which is portable. It may also be known as a notebook. The sony PCGA-BP71 battery  typical laptop will only weight a few pounds and will generally have an internal battery as well as a power adapter.

A laptop is a personal computer which is portable. It may also be known as a notebook. The typical laptop will range in weight from 1 to 3 kilograms, and will generally have an internal sony VGP-BPS3 battery as well as a power adapter. While most laptops are portable, few can currently match the power of the most expensive desktops, though this will likely change as technology continues to advance. The word laptop was first introduced in 1983, and was used to refer to the Gavilan SC. Despite the name, most laptops should not be placed in your lap if it is not covered, because they can get hot, and can even burn skin that is held against it for extended periods of time. The typical laptop can be powered by one battery, and the power adapter can power the sony PCGA-BP2NY battery when it is plugged into a wall outlet. A laptop can perform many of the same tasks as a PC, but they tend to be limited. They will have the same internal devices which are seen in desktops, but they will be much smaller in size. Most laptops will have a screen which uses a liquid crystal display. Most manufacturers have designed their laptops to work with a keyboard and mouse, and they will also have a touch pad that can be used to move around the cursor on the screen. Laptops come in three varieties, and these are based on the size. An ultraportable laptop will generally weigh less than 1.7 kilograms, while a thin and light laptop will weigh up to 2.8 kilograms, and a medium sized laptop will weigh up to 3.5 kilograms. The idea for the laptop existed prior to the invention of the personal computer, and was first conceived during the 1970s. The very first laptop was the Osborne 1, and it was released in 1981. While the Osborne 1 was massive in comparison to contemporary laptops, it was revolutionary for its time, because it allowed people to carry their data with them, and the computer didn¡¯t have to be left in a single location. However, the Osborne 1 was so large that it was not possible to run it on a battery. Most laptops today now use lithium ion sony PCGA-BP2NX battery. While laptops have a few advantages over their desktop counterparts, they have some disadvantages as well. Unlike desktops, they are limited in their ability to be upgraded. As of this writing, their is no form factor for laptops, and the costs and technical issues involved with making them easy to upgrade aren¡¯t feasible. The only parts of most laptops that can easily be upgraded are the hard drive and RAM. In addition to this, laptops are expensive to repair if they are damaged, and they are also easy to steal due to their small size. Stolen sony VGP-BPS2 battery are a common cause for identity theft. While the use of the USB port has allowed laptops to be upgraded to some degree, it will typically reduce their portability. Historically, the performance of laptops has always been low when they were compared to desktops in the same price range.

Jun. 13, 2008 -

We are specialized in produce, sale and after service of laptop batteries ,PDA&SmartPhone batteries and charger, digital camera batteries and camcorder batteries. Currently, our products are very popular in many countries in North America, Europe, Middle East and South-east Asia etc.This Fujitsu FPCBP68 battery Pack is a replacement Li-ion battery for laptop. Only the high quality Panasonic LG,Samsung cells were used in our laptop batteries.All our laptop batteries have been UL, CE and ROHS certified,include Fujitsu FPCBP68 battery.All the bateries from our company are full one year warranty, 30 days money back

Jun. 13, 2008 -

We are specialized in produce, sale and after service of laptop batteries ,PDA&SmartPhone batteries and charger, digital camera batteries and camcorder batteries. Currently, our products are very popular in many countries in North America, Europe, Middle East and South-east Asia etc.This Fujitsu FPCBP68 battery Pack is a replacement Li-ion battery for laptop. Only the high quality Panasonic LG,Samsung cells were used in our laptop batteries.All our laptop batteries have been UL, CE and ROHS certified,include Fujitsu FPCBP68 battery.All the bateries from our company are full one year warranty, 30 days money back

Jun. 13, 2008 -

We are specialized in produce, sale and after service of laptop batteries ,PDA&SmartPhone batteries and charger, digital camera batteries and camcorder batteries. Currently, our products are very popular in many countries in North America, Europe, Middle East and South-east Asia etc.This Fujitsu FPCBP68 battery Pack is a replacement Li-ion battery for laptop. Only the high quality Panasonic LG,Samsung cells were used in our laptop batteries.All our laptop batteries have been UL, CE and ROHS certified,include Fujitsu FPCBP68 battery.All the bateries from our company are full one year warranty, 30 days money back