batteries blog

The voltage and temperature

Battery charging process can generally be classified into pre-charge, fast charge

     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 η Ah efficiency of 67% -75%, electric energy efficiency η Wh 55% to 65%, cycle life of about 2000 times. Η Ah capacity and efficiency of electric energy efficiency η 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-→ O2 ↑ +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

The Li-Polymer battery

The word ‘Lithium Polymer’ has become synonymous with advanced battery technology. But what is the relationship between ‘polymer’ and the classic Lithium Ion battery? In this article we examine the basic differences between the Li-ion and Li-ion polymer battery. We look at packaging techniques and evaluate the cost-to-energy ratio of these batteries. Sony panasonic Canon JVC Samsung Sharp HITACHI

The Li-polymer differs from other battery systems in the type of electrolyte used. The original design, which dates back to the 1970s, uses a polymer electrolyte. This electrolyte resembles a plastic-like film that does not conduct electricity but allows the exchange of ions (electrically charged atoms or groups of atoms). The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte.Canon Sony Nikon Olympus Kodak Panasonic minolta Casio Ricoh Pentax FUJIFILM Kyocera Samsung sanyo laptop driver laptop batteries

The dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile profile. There is no danger of flammability because no liquid or gelled electrolyte is used.

With a cell thickness measuring as little as one millimeter (0.039 inches), design engineers are left to their own imagination in terms of form, shape and size. Theoretically, it is possible to create designs which form part of a protective housing, are in the shape of a mat that can be rolled up, or are even embedded into a carrying case or a piece of clothing. Such innovative Apple A1078 battery are still a few years away, especially for the commercial market.

Unfortunately, the dry Li-polymer suffers from poor conductivity. The internal resistance is too high and cannot deliver the current bursts needed for modern communication devices and spinning up the hard drives of mobile computing equipment. Although heating the cell to 60°C (140°F) and higher increases the conductivity to acceptable levels. This requirement, however, is unsuitable for portable applications.

Some dry solid Li-polymers are currently used in hot climates as standby Dell 1691P battery for stationary applications. One manufacturer has added heating elements in the cells that keep the battery in the conductive temperature range at all times. Such a battery performs well for the application intended because high ambient temperatures do not degrade the service life of this battery in the same way as it does with the VRLA type. Although longer lasting, the cost of the Li-polymer Dell Inspiron 6000 battery is high. 

Engineers are continuing to develop a dry solid Li-polymer battery that performs at room temperature. A dry solid Li-polymer version is anticipated by 2005. This battery should be very stable; would run 1000 full cycles and would have higher energy densities than today’s Li‑ion Dell U4873 battery.

How then is the current Li-polymer Dell Latitude D500 battery made conductive at ambient temperatures?  Most of the commercial Li-polymer batteries or mobile phones are a hybrid. Some gelled electrolyte has been added to the dry polymer. The correct term for this system is Lithium Ion Polymer. For marketing reasons, most Dell Latitude D820 battery manufacturers call it simply Li-polymer. Since the hybrid lithium polymer is the only functioning polymer battery for portable use today, we will focus on this chemistry variation but use the correct term of lithium ion polymer (Li-ion polymer).

With gelled electrolyte added, what then is the difference between Li‑ion and Li‑ion polymer? Although the characteristics and performance of the two systems are very similar, the Li‑ion polymer is unique in that the solid electrolyte replaces the porous separator. The gelled electrolyte is simply added to enhance ion conductivity.

Technical difficulties and delays in volume manufacturing have deferred the introduction of the Li‑ion polymer Dell Latitude D810 battery. In addition, the promised superiority of the Li‑ion polymer has not yet been realized. No improvements in capacity gains are achieved — in fact, the capacity is slightly less than that of the standard Li‑ion battery. For the present, there is no cost advantage in using the Li‑ion polymer battery. The major reason for switching to the Li-ion polymer is form factor. It allows wafer-thin geometries, a style that is demanded by the highly competitive mobile phone industry. Figure 1 summarizes the advantages and limitations of the Li-ion polymer Dell Latitude D520 battery.

Advantages and Limitations of Li-ion Polymer Batteries
Advantages	Very low profile — batteries that resemble the profile of a credit card are feasible. Flexible form factor — manufacturers are not bound by standard cell formats. With high volume, any reasonable size can be produced economically.Apple M6091 battery Light weight – gelled rather than liquid electrolytes enable simplified packaging, in some cases eliminating the metal shell. Improved safety — more resistant to overcharge; less chance for electrolyte leakage.
Limitations	Lower energy density and decreased cycle count compared to Li-ion — potential for improvements exist. Expensive to manufacture — once mass-produced, the Li-ion polymer has the potential for lower cost. Reduced control circuit offsets higher manufacturing costs.

Figure 1: Advantages and limitations of Li‑ion polymer HP F4486B battery.

The pouch cell

The Li-ion polymer HP DP390A battery is almost exclusively packaged in the so-called ‘pouch cell’. This cell design made a profound advancement in 1995 when engineers succeeded in exchanging the hard shell with flexible, heat-sealable foils. The traditional metallic cylinder and glass-to-metal electrical feed-through has thus been replaced with an inexpensive foil packaging, similar to what is used in the food industry. The electrical contacts consist of conductive foil tabs that are welded to the electrode and sealed to the pouch material. Figure 2 illustrates a typical pouch cell.Apple M8244 battery

The pouch cell concept makes the most efficient use of available space and achieves a packaging efficiency of 90 to 95 percent, the highest among battery packs. Because of the absence of a metal can, the pouch pack has a lower weight. No standardized pouch cells exist, but rather, each manufacturer builds to a special application.

At the present time, the pouch cell is more expensive to manufacture than the cylindrical architecture and the reliability has not been fully proven. The energy density and load current are slightly lower than that of conventional cell designs. The cycle life in everyday applications is not well documented but is, at present, less than that of the Li‑ion HP nc6120 battery  system with cylindrical cell design.

A critical issue with the pouch cell is swelling, which occurs when gas is generated during charging or discharging. HP F2024A battery manufacturers insist that Li‑ion or Polymer cells do not generate gas if properly formatted, are charged at the correct current and are kept within allotted voltage levels. When designing the protective housing for a pouch cell, some provision for swelling must be taken into account. To alleviate the swelling issue when using multiple cells, it is best not to stack pouch cells, but lay them flat side-by-side.

The pouch cell is highly sensitive to twisting. Point pressure must also be avoided. The protective housing must be designed to safeguard the cell from mechanical stress.

The cost of being slim

The slimmer the battery profile, the higher the cost–to-energy ratio becomes. By far the most economical lithium-based battery is the cylindrical 18650 cell. ‘Eighteen’ denotes the diameter in millimeters and ‘650’ describes the length in millimeters. The new 18650 cell has a capacity 2000mAh. The larger 26650 cell has a diameter of 26 mm and delivers 3200mAh. HP DP399A battery

The disadvantage of the cylindrical cell is bulky size and less than maximum use of space. When stacking, air cavities are formed. Because of fixed cell sizes, the HP F2019 battery  pack must be designed around the available cell.

If a thinner profile than 18 mm is required, the prismatic Li‑ion cell is the best choice. The cell concept was developed in the early 1990s in response to consumer demand for slimmer pack sizes. The prismatic cell makes almost maximum use of space when stacking.

The disadvantage of the prismatic cell is slightly lower energy densities compared to the cylindrical equivalent. In addition, the prismatic cell is more expensive to manufacture and does not provide the same mechanical stability enjoyed by the cylindrical cell. To prevent bulging when pressure builds up, heavier gauge metal is used for the container. The manufacturer allows some degree of bulging when designing the HP F2024 battery pack.

The prismatic cell is offered in limited sizes and chemistries and the capacities run from about 400mAh to 2000mAh. Because of the very large quantities required for mobile phones, custom prismatic cells are built to fit certain models.

If the design requirements demand less than 4 mm, the best (and perhaps the only choice) is Li‑ion polymer. This is the most expensive option.  The cost-to-energy ratio more than doubles. The benefit of this architecture is strictly slim geometry. There is little or no gain in energy density per weight and size over the 18650, even though the metal housing has been eliminated.HP F2299A battery

SummaryHP Pavilion ZD7000 battery

The Li-ion polymer offers little or no energy gain over conventional Li‑ion systems; neither do the slim profile Li-ion systems meet the cycle life of the rugged 18560 cell. The cost-to-energy ration increases as the cell size decreases in thickness. Cost increases in the multiple of three to four compared to the 18650 cell are common on exotic slim battery designs. Compaq Evo N620C battery

If space permitted, the 18650 cell offers the most economical choice, both in terms of energy per weight and longevity. Applications for this cell are mobile computing and video cameras. Slimming down means thinner batteries. This, in turn, will make the cost of the portable power more expensive

The Nickel Cadmium (NiCd) battery

The NiCd prefers fast charge to slow charge and pulse charge to DC charge. All other chemistries prefer a shallow discharge and moderate load currents. The NiCd is a strong and silent worker; hard labor poses no problem. In fact, the NiCd is the only battery type that performs well under rigorous working conditions. It does not like to be pampered by sitting in chargers for days and being used only occasionally for brief periods. A periodic full discharge is so important that, if omitted, large crystals will form on the cell plates (also referred to as memory) and the NiCd will gradually lose its performance.

Among rechargeable batteries, NiCd remains a popular choice for applications such as two-way radios, emergency medical equipment and power tools. Batteries with higher energy densities and less toxic metals are causing a diversion from NiCd to newer technologies.

Advantages and Limitations of NiCd Batteries
Advantages	Fast and simple charge — even after prolonged storage.Dell Inspiron 6000 battery High number of charge/discharge cycles — if properly maintained, the NiCd provides over 1000 charge/discharge cycles.Dell laptop battery Good load performance — the NiCd allows recharging at low temperatures. Long shelf life – in any state-of-charge. Simple storage and transportation — most airfreight companies accept the NiCd without special conditions. Good low temperature performance. Forgiving if abused — the NiCd is one of the most rugged rechargeable batteries. Economically priced — the NiCd is the lowest cost battery in terms of cost per cycle. Available in a wide range of sizes and performance options — most NiCd cells are cylindrical.
Limitations	Relatively low energy density — compared with newer systems. Memory effect — the NiCd must periodically be exercised to prevent memory. Environmentally unfriendly — the NiCd contains toxic metals. Some countries are limiting the use of the NiCd battery. Has relatively high self-discharge — needs recharging after storage.

When was the battery invented

One of the most remarkable and novel discoveries in the last 400 years has been electricity. You may ask, “Has electricity been around that long?” The answer is yes, and perhaps much longer. But the practical use of electricity has only been at our disposal since the mid-to late 1800s, and in a limited way at first. At the world exposition in Paris in 1900, for example, one of the main attractions was an electrically lit bridge over the river Seine.laptop driver

The earliest method of generating electricity occurred by creating a static charge. In 1660, Otto von Guericke constructed the first electrical machine that consisted of a large sulphur globe which, when rubbed and turned, attracted feathers and small pieces of paper. Guericke was able to prove that the sparks generated were truly electrical. laptop batteries

The first suggested use of static electricity was the so-called “electric pistol”. Invented by Alessandro Volta (1745-1827), an electrical wire was placed in a jar filled with methane gas. By sending an electrical spark through the wire, the jar would explode.

Volta then thought of using this invention to provide notebook batteries long distance communications, albeit only addressing one Boolean bit. An iron wire supported by wooden poles was to be strung from Como to Milan, Italy. At the receiving end, the wire would terminate in a jar filled with methane gas. On command, an electrical spark is sent by wire that would detonate the electric pistol to signal a coded event. This communications link was never built.

In 1791, while working at Bologna University, Luigi Galvani discovered that the muscle of a frog contracted when touched by a metallic object. This phenomenon became known as animal electricity — a misnomer, as the theory was later disproven. Prompted by these experiments, Volta initiated a series of experiments using zinc, lead, tin or iron as positive plates. Copper, silver, gold or graphite were used as negative plates.camcorder

The next stage of generating electricity was through electrolysis. Volta discovered in 1800 that a continuous flow of electrical force was generated when using certain fluids as conductors to promote a chemical reaction between the metals or electrodes. This led to the invention of the first voltaic cell, better know as the battery. Volta discovered further that the voltage would increase when voltaic cells were stacked on top of each other.

Figure 2:  Four variations of Volta’s electric battery.
Silver and zinc disks are separated with moist paper. © Cadex Electronics Inc.

In the same year, Volta released his discovery of a continuous source of electricity to the Royal Society of London. No longer were experiments limited to a brief display of sparks that lasted a fraction of a second. A seemingly endless stream of electric current was now available.

France was one of the first nations to officially recognize Volta’s discoveries. At the time, France was approaching the height of scientific advancements and new ideas were welcomed with open arms to support the political agenda. By invitation, Volta addressed the Institute of France in a series of lectures at which Napoleon Bonaparte was present as a member of the Institute.

Figure 3: Volta’s experimentations at the French National Institute.
Volta’s discoveries so impressed the world that in November 1800, he was invited by the French National Institute to lectures in which Napoleon Bonaparte participated. Later, Napoleon himself helped with the experiments, drawing sparks from the battery, melting a steel wire, discharging an electric pistol and decomposing water into its elements. © Cadex Electronics Inc.

New discoveries were made when Sir Humphry Davy, inventor of the miner’s safety lamp, installed the largest and most powerful electric battery in the vaults of the Royal Institution of London. He connected the battery to charcoal electrodes and produced the first electric light. As reported by witnesses, his voltaic arc lamp produced “the most brilliant ascending arch of light ever seen.”

Davy's most important investigations were devoted to electrochemistry. Following Galvani's experiments and the discovery of the voltaic cell, interest in galvanic electricity had become widespread. Davy began to test the chemical effects of electricity in 1800. He soon found that by passing electrical current through some substances, these substances decomposed, a process later called electrolysis. The generated voltage was directly related to the reactivity of the electrolyte with the metal. Evidently, Davy understood that the actions of electrolysis and the voltaic cell were the same.

In 1802, Dr. William Cruickshank designed the first electric battery capable of mass production. Cruickshank had arranged square sheets of copper, which he soldered at their ends, together with sheets of zinc of equal size. These sheets were placed into a long rectangular wooden box that was sealed with cement. Grooves in the box held the metal plates in position. The box was then filled with an electrolyte of brine, or watered down acid.

Figure 4: Cruickshank and the first flooded battery.
William Cruickshank, an English chemist, built a battery of electric cells by joining zinc and copper plates in a wooden box filled with electrolyte. This flooded design had the advantage of not drying out with use and provided more energy than Volta’s disc arrangement. © Cadex Electronics Inc.

The third method of generating electricity was discovered relatively late — electricity through magnetism. In 1820, André-Marie Ampère (1775-1836) had noticed that wires carrying an electric current were at times attracted to one another, while at other times they were repelled.

In 1831, Michael Faraday (1791-1867) demonstrated how a copper disc was able to provide a constant flow of electricity when revolved in a strong magnetic field. Faraday, assisting Davy and his research team, succeeded in generating an endless electrical force as long as the movement between a coil and magnet continued. The electric generator was invented. This process was then reversed and the electric motor was discovered. Shortly thereafter, transformers were developed that could convert electricity to a desired voltage. In 1833, Faraday established the foundation of electrochemistry with Faraday's Law, which describes the amount of reduction that occurs in an electrolytic cell.

In 1836, John F. Daniell, an English chemist, continued with the research of the electro-chemical battery and developed an improved cell that produced a steadier current than Volta's device. Until then, all batteries had been composed of primary cells, meaning that they could not be recharged. In 1859, the French physician Gaston Platé invented the first rechargeable battery. This secondary battery was based on lead acid chemistry, a system that is still used today.

History of Battery Development
1600	Gilbert (England)	Establishment electrochemistry study
1791	Galvani (Italy)	Discovery of ‘animal electricity’
1800	Volta (Italy)	Invention of the voltaic cell
1802	Cruickshank (England)	First electric battery capable of mass production
1820	Ampère (France)	Electricity through magnetism
1833	Faraday (England)	Announcement of Faraday’s Law
1836	Daniell (England)	Invention of the Daniell cell
1859	Planté (France)	Invention of the lead acid battery
1868	Leclanché (France)	Invention of the Leclanché cell
1888	Gassner (USA)	Completion of the dry cell
1899	Jungner (Sweden)	Invention of the nickel-cadmium battery
1901	Edison (USA)	Invention of the nickel-iron battery
1932	Shlecht & Ackermann (Germany)	Invention of the sintered pole plate
1947	Neumann (France)	Successfully sealing the nickel-cadmium battery
Mid 1960	Union Carbide (USA)	Development of primary alkaline battery
Mid 1970		Development of valve regulated lead acid battery
1990		Commercialization nickel-metal hydride battery
1992	Kordesch (Canada)	Commercialization reusable alkaline battery
1999		Commercialization lithium-ion polymer
2001		Anticipated volume production of proton exchange membrane fuel cell

Figure 5:  History of battery development.
The battery may be much older. It is believed that the Parthians who ruled Baghdad (ca. 250 bc) used batteries to electroplate silver. The Egyptians are said to have electroplated antimony onto copper over 4300 years ago.

In 1899, Waldmar Jungner from Sweden invented the nickel-cadmium new laptop batteris, which used nickel for the positive electrode and cadmium for the negative. Two years later, Edison produced an alternative design by replacing cadmium with iron. Due to high material costs compared to dry cells or lead acid storage batteries, the practical applications of the nickel-cadmium and nickel-iron batteries were limited.Inspiron 6000

Toward the end of the 1800s, giant generators and transformers were built. Transmission lines were installed and electricity was made available to humanity to produce light, heat and movement. In the early twentieth century, the invention of the vacuum tube enabled generating controlled signals, amplifications and sound. Soon thereafter, radio was invented, which made wireless communication possible.Toshiba

It was not until Shlecht and Ackermann invented the sintered pole plate in 1932 when profound improvements were achieved. These advancements were reflected in higher load currents and improved longevity. The sealed nickel-cadmium battery, as we know it toady, became only available when Neumann succeeded in completely sealing the cell in 1947.