Excessive water consumption can be indicative of overcharging

July 09 [Tue], 2013, 11:52
Emergency batteries that are connected to the bus are constantly in charge and thus continuously evaporate water from the electrolyte. As the electrolyte level drops and the plate separator begins to be exposed (dried out in extreme cases), the separator material begins to deteriorate which results in cell VGP-BPS13AB laptop battery heating and shorts in extreme cases.
Batteries that are subject to continuous charging and have little or no opportunity to deliver power, need to be removed periodically, first to check the water level and second to check for capacity.

Water level checking cannot be performed on the aircraft. It can only be performed under bench test conditions with a constant current charger and only when the battery has reached full charge. Excessive water consumption can be indicative of overcharging (bus voltage too high) or infrequent servicing, or both. The time required for this test will range from one day for a "good" battery to several days for a "problem battery".

Since emergency batteries are basically in stand-by condition and are subject to continuous charging, their capacity to deliver current when needed slowly diminishes (capacity fading), so it is also necessary to periodically perform a capacity test. If this test is passed marginally, or not at all, the cells have to be deep cycled (total discharge) to restore the rated capacity. Depending on the severity of the fading, the total discharge and subsequent recharge must be performed several times before proper capacity restoration will occur. The time required for this type of testing will require from two days for a "good" battery to a full week for a "problem" battery.

Batteries that do not pass the required tests can be repaired by replacing the individual cells that fail the specific tests, but not more than 20% of the total number of cells in the battery (4 to 5 cells) should be replaced. If more than 20% of the cells need to be replaced, the entire battery needs to be replaced (this is done to minimize the mismatching between new cells and old cells).

Under normal conditions, most batteries are expected to last five to six years, provided that they are serviced properly (Including occasional cell replacement). This is true even for the larger batteries that are used to start VGP-BPS13B/B laptop battery engines or APU’s. But, with improper maintenance (basically infrequent maintenance) the life of the batteries will be significantly shorter. If servicing is infrequent, by the time that the batteries are finally removed for testing, it may be too late.

Proper servicing is costly. Time to do it, proper personnel, availability of a replacement battery, service charges by the battery shop, etc. But, if as a result of inadequate servicing the battery must be replaced, its cost far exceeds the cost of proper servicing. This is also true if a battery failure results in a grounded airplane. Finally, the cost of an in-flight battery failure (Overheating, little or no capacity to provide power, etc.) could have more severe consequences.

With recurring accidents while transporting lithium-based batteries by air

May 21 [Tue], 2013, 17:13
Reputable battery manufacturers do not supply lithium-ion cells to uncertified battery assemblers. This precaution is reasonable when considering the danger of explosion and fire when charging and discharging a Li-ion pack beyond Acer AS10D75 cheapsafe limits without an approved protection circuit.

Authorizing a battery pack for the commercial market and for air transport can cost $10,000 to $20,000. Such a high price is troubling when considering that obsolescence in the battery industry is common. Manufacturers often discontinue a cell in favor of higher capacities. The switch to the improved cell will require a new certification even though the dimensions of the new cell are the same as the previous model.

Cell manufacturers must comply with their own vigorous cell testing and we ask, “Why are additional tests required when using an approved cell?” The cell approvals cannot be transferred to the pack because the regulatory authorities do not recognize the safety confirmation of the naked cell. The finished battery must be tested separately to assure correct assembly and is registered as a standalone product. Read about Safety Concerns with Li-ion.

As part of the test, the finished battery must undergo electrical and mechanical assessment to meet the Recommendations on the Transport of Dangerous Goods on lithium-ion batteries for air shipment, rules set by the United Nations (UN). The electrical test stresses the battery by applying high heat, followed by a forced charge, abnormal discharge and an electrical short. During the mechanical test, the battery is crush-tested and exposed to high impact, shock and vibration. The UN Transport test also requires altitude, thermal stability, vibration, shock, short circuit and overcharge checks. The UN Transport works in conjunction with the Federal Aviation Administration(FAA), the US Department of Transport (US DOT) and the International Air Transport Association (IATA).

The authorized laboratory performing the tests needs 24 battery samples consisting of 12 new packs and 12 specimens that have been cycled for 50 times. IATA wants to assure that the batteries in question are airworthy and have field integrity. Cycling them for 50 times before the test satisfies this requirement.

The high certification costs make many small manufacturers shy away from using Li-ion for low-volume products; they choose nickel-based systems instead. While strict control is justified, an uncertified Li-ion kept in the hands of the expert and out of aircraft would be acceptable, but controlling such movement in the public domain is next to impossible. This makes it hard for the hobbyist who wants to win a r AL10C31 cheapace with a high-powered Li-ion battery but is bogged down by many rules.

With recurring accidents while transporting lithium-based batteries by air, regulatory authorities will likely tighten the shipping requirements further. However, anything made too cumbersome and difficult will entice some battery manufacturers to trick the system, defeating the very purpose of protecting the traveling public. Read about How to Transport Batteries.

The advantage of nickel-cadmium over nickel-metal-h

February 20 [Wed], 2013, 14:53
Most two-way radios use nickel-cadmium. These batteries are durable and forgiving if abused. But nickel-cadmium batteries have only moderate energy density and are environmentally unfriendly. Environmental agencies have been discouraging its use, especially in Europe. The recommended alternative is 6 cell Latitude E6400 nickel-metal-hydride, a battery that has higher energy density and contains no toxic metals. nickel-metal-hydride has been tested in two-way radios for a number of years but the results are mixed. Shorter than expected service life is the major drawback.

For two-way radios, nickel-metal-hydride has a cycle life, which is half that of standard nickel-cadmium. Nickel-metal-hydride prefers a moderate discharge current of 0.5C or less. A two-way radio, on the other hand, draws a discharge current of about 1.5A when transmitting at 4W of power. High discharge loads and sharp pulse currents shorten battery life.

To compare the longevity of nickel-metal-hydride under different load condition, a test was carried out in which batteries of the same type were discharged with a DC and digital load. In both tests, the batteries were discharged to 1.04 volts per cell. The DC load was a steady 500mA; the digital load simulated the Global System for Mobile Communications (GSM) at 1.65 ampere peak for 12 ms every 100 ms with 270 mA standby. (Note that the GSM pulse for voice is about 550 ms every 4.5 ms).

With the DC discharge, nickel-metal-hydride wore out gradually, providing an above average service life. At 700 cycles, the battery still provided 80% capacity. By contrast, the same battery type faded more rapidly with a digital discharge and the 80% capacity threshold was reached after only 300 cycles. This phenomenon indicates that the kinetic characteristics for nickel-metal-hydride deteriorate more rapidly with a digital than analog load. Although the test was simulating a GSM cell phone, Tetra and other digital two-way radios have similar loading.

Let's briefly compare the characteristics of nickel-cadmium and nickel-metal-hydride. nickel-cadmium has the advantage of maintaining steady high capacity and low internal resistance through most of its service life. nickel-metal-hydride, on the other hand, starts with good capacity and low internal resistance but the resistance increases after a few hundred cycles, causing the voltage to drop on a load. Even though the energy may still be present, the battery cannot deliver the high current during transmit and the message cuts off. The radio becomes unreliable.

Nickel-based batteries are high in maintenance. Periodic discharge cycles are needed to prevent crystalline formation on the cell plates, also known as memory. Nickel-cadmium is more receptive to memory than nickel-metal-hydride because both nickel and cadmium plates are affected by memory.

Nickel-cadmium should be exercised once ever 1 to 2 months, whereas nickel-metal-hydride can get by with a deliberate full discharge once every 3 months. Without proper maintenance, the advantage of nickel-cadmium over nickel-metal-hydride in terms of cycle life cannot be realized.

Lithium-ion has been tested for two-way radios and the results are positive. Substituting lithium-ion with nickel-based will require chargers specifically suited for this chemistry. While nickel-cadmium and nickel-metal-hydride 6 cell Studio 1555 batterycan often share the same charger, lithium-ion uses a different charge algorithm. There is also a cost premium for lithium-ion. Future two-way radios will undoubtedly be fitted with lithium-ion.

This allows lithium-ion to be kept in the chargers until used

February 20 [Wed], 2013, 14:52
Early cell phones were powered with nickel-based batteries but most newer phones are now equipped with lithium-ion. This chemistry is lightweight, offers high energy density and lasts long enough to span the typical life of the 6 cell Vostro 1400 product. Lithium-ion contains no toxic metals.
To obtain thin geometry, some cell phone manufacturers switched to lithium-ion-polymer.

This satisfied consumer requests for slim designs. In the meantime, technological advancements also made low profile lithium-ion possible. lithium-ion packs are now available in 3 mm, a profile that suits most designs. lithium-ion has the advantage of lower manufacturing cost, better performance and longer cycle life than the polymer version.

Lithium-ion is a low maintenance battery. No periodic discharge is needed and charging can be done at random. A random charge means that the battery does not need to be fully depleted before recharge. In fact, it is better to recharge before the battery gets too low. Full discharges put an unnecessary strain on the battery. A recharge on a partially charged battery does not cause memory because there is none.

Charging lithium-ion is simpler and cleaner than nickel-based batteries but the chargers require tighter tolerances. Lithium-ion cannot absorb overcharge and no trickle charge is applied on full charge. This allows lithium-ion to be kept in the chargers until used. Some chargers apply a topping charge every week or so to replenish the capacity lost through self-discharge while the battery sits idle in the charger. Repeated insertion into the charger or cradle does not damage the battery though 6 cell KM742overcharge. If the battery is full, no charge is applied. The battery voltage determines the need to charge.

On the negative side, lithium-ion gradually loses charge acceptance as part of aging, even if not used. lithium-ion batteries should not be stored for long periods but be rotated like perishable food. The buyer should be aware of the manufacturing date when purchasing a replacement battery. Aging affects battery chemistries at different degrees.

External Level 3 chargers are complex and expensive

December 18 [Tue], 2012, 15:02
The SMBus is the most complete of all systems. It represents a large effort from the electronics industry to standardize on one communications protocol and one set of data. The Duracell/Intel SBS, which is in use today, was standardized in 1993. It is a two-wire interface system consisting of separate lines for the datahigh quality A32-F80 and clock. Figure 2 shows the layout of the two-wire SMBus system.

The objective behind the SMBus battery is to remove the charge control from the charger and assign it to the battery. With a true SMBus system, the battery becomes the master and the charger serves as slave that must follow the dictates of the battery.

Battery-controlled charging makes sense when considering that some packs share the same footprint but contain different chemistries, requiring alternative charge algorithms. With the SMBus, each battery receives the correct charge levels and terminates full-charge with proper detection methods. Future battery chemistries will be able to use the existing chargers.

An SMBus battery contains permanent and temporary data. The permanent data is programmed into the battery at the time of manufacturing and includes battery ID number, battery type, serial number, manufacturer's name and date of manufacture. The temporary data is acquired during use and consists of cycle count, user pattern and maintenance requirements. Some of this information is renewed during the life of the battery.

The SMBus is divided into Level 1, 2 and 3. Level 1 has been eliminated because it does not provide chemistry independent charging. Level 2 is designed for in-circuit charging. A laptop that charges its battery within the unit is a typical example of Level 2. Another Level 2 application is a battery that contains the charging circuit within the pack. Level 3 is reserved for full-featured external chargers.

External Level 3 chargers are complex and expensive. Some lower cost chargers have emerged that accommodate SMBus batteries but are not fully SBS compliant. Manufacturers of SMBus batteries do not fully endorse this shortcut. Safety is always a concern, but customers buy them because of low cost. Serious industrial battery users operating biomedical instruments, data collection devices and survey equipment use Level 3 chargers with full-fledged charge protocol.

Among the most popular SMBus batteries are the 35 and 202 form-factors (Figure 3). Manufactured by Sony, Hitachi, GP Batteries, Moli Energy and others, these batteries work (should work) in all portable equipment designed for this system. Although the 35 has a smaller footprint than the 202, most chargers accommodate both sizes. A non-SMBus ('dumb') version with same footprint is also available.

These batteries can only be charged with a regular charger, or one that accepts both In spite of the agreed standard and given form factors, many computer manufacturers have retained their proprietary cheap A1309. Safety, performance and form factor are the reasons. They argue that enduring performance can only be guaranteed if their own brand battery is used. This makes common sense but the leading motive may be pricing. In the absence of competition, these batteries can be sold for a premium price.

The single wire system stores the battery code and tracks battery readings

December 18 [Tue], 2012, 14:56
The single wire system delivers the data communications through one wire. This battery uses three wires: the common positive and negative battery terminals and one single data terminal, which also provides the clockRechargeable A32-UL20 information. For safety reasons, most battery manufacturers run a separate wire for temperature sensing. Figure 1 shows the layout of a single wire system.

The single wire system stores the battery code and tracks battery readings, including temperature, voltage, current and SoC. Because of relatively low hardware cost, the single wire system enjoys market acceptance for high-end two-way radios, camcorders and portable computing devices.

Most single wire systems do not provide a common form factor; neither do they lend themselves to standardized SoH measurements. This produces problems for a universal charger concept. The Benchmarq single wire solution, for example, cannot measure the current directly; it must be extracted from a changelithium A32-K53 in capacity over time.

In addition, the single wire bus allows battery SoH measurement only when the host is 'married' to a designated battery pack. Such a fixed host-battery relationship is only feasible if the original battery is used. Any discrepancy in the battery will make the system unreliable or will provide false readings.

Some industry executives including engineering chiefs from two global auto makers

October 30 [Tue], 2012, 11:37
But that could prove compromised as leading Chinese auto parts firm Wanxiang Group Corp's $465 million investment in A123 Systems Inc, a struggling U.S. maker of lithium-ion batteries, may help China unlock the secrets11.1v 5200mah 9cells Presario CQ40 battery to critical and advanced green-car technologies.

The investment has ruffled feathers in the run-up to the presidential election in the United States as A123 receives government grants tied to it keeping production and jobs in the U.S. during an economic downturn that has seen unemployment levels remain stubbornly above 8 percent.

Some industry executives including engineering chiefs from two global auto makers, who did not want to be named because of the sensitivity of the matter, expressed concern at the prospect that A123 could lose control of its fiercely guarded battery design and manufacturing know-how. They are particularly worried that Wanxiang might shift part of A123's research and development replacement Presario CQ42 batteryactivities to China - if the deal wins U.S. and Chinese government approval.

"I don't care if A123 manufactures more battery cells and packs in China. That wouldn't jeopardize its technological advantage," said a chief engineer at one global automaker. "But showing what's inside their black box ... the technology that makes those battery cells packed with energy, to its Chinese investor, which has its own battery business, is completely another matter."

Lithium-ion batteries that can hold twice as much energy as they currently do

October 30 [Tue], 2012, 11:36
By swapping graphite for silicon as an electrode material, two start-ups have announced they'll make lithium-ion batteries that can hold twice as much energy as they currently do. Both companies―-Nexeon, in Abingdon, England, and Amprius, in Menlo Park, Calif.―-say they expect their silicon electrode battery for Presario A900 battery technology to hit the market in the next couple of years.

Meanwhile, Nanosys has developed a solution to using silicon compounds in lithium batteries. It's been long known this could dramatically improve energy density, or the amount of energy held per kilogram of battery, but volumetric expansion, whenever was a problem.

Batteries from Nonsys use silicon bright Presario C700 batterycompounds without the volumetric expansion problem, claiming doubled battery capacity. The company says it hopes to fulfill the U.S. Department of Energy target to bring the cost of lithium-ion batteries down to $250/kWh while increasing capacity to 300 miles per charge.

Figure 1 lithium iron phosphate battery charge and discharge voltage curve

June 19 [Tue], 2012, 16:18
It comes to electric vehicles, the first thought was the carrier of the power source - the lithium-ion battery of the group application. The industry has been keen to discuss the issue of battery safety, cycle life and battery group consistency, the "inflection point" issue on lithium-ion battery does not seem to be concerned about. "Inflection point" refers to the phenomenon of the turning point of the lithium-ion battery charge and discharge early and 85% -95% of the stage power curve. This is the electrochemical characteristics of the battery itself dictates, battery hp 497695-001temperature, ambient temperature and charge and discharge currents and other factors will affect the inflection point of the form.
Lithium iron phosphate battery charge and discharge the turning point of the phenomenon and mechanism

One the 180Ah phosphate Asia CITIZEN lithium lithium-ion batteries at room temperature 1/3C charge and discharge voltage curve shown in Figure 1. The platform of charge and discharge voltage is about 3.35V, two inflection point of the charging voltage is 3.25V and 3.45V; two inflection point of the discharge voltage is 3.4V and 3.1V.

Figure 1 lithium iron phosphate battery charge and discharge voltage curve

It can be seen from the curve in Figure 1, the battery voltage in the charge / discharge of the early and late, have a period of rapidly rising, and the rapid decline of the focus on the inflection point of the end of the charge / discharge phenomena.

The charging process of the lithium intercalation and deintercalation of lithium ions from the cathode migrate to the anode and the embedded process. When the positive electrode of lithium ion deintercalation to a certain number, by John-Teller effect of the lithium ion deintercalation will become increasingly difficult and require more energy to emerge from the positive plate. The external manifestations of the polarization resistance increases, a sharp rise in voltage. Discharge, the lithium ion deintercalation from the cathode, migrate to the cathode, and embedded into the cathode lattice. When the number of negative electrode of lithium-ion is reduced to a certain extent, the surface of the electrode reaction speed reduced, the resistance increases rapidly, causing a rapid decline in battery voltage.

"Inflection point phenomenon and the safety of lithium-ion battery

Test report issued by the department on the domestic authority and based on 10% of the remaining capacity after the relevant statistics obtained inflection point is less than the total battery capacity, battery effective working platform more than 90% of the total capacity. The experiments show that the end of the charge / discharge "inflection point phenomenon" of the battery capacity is nearly full or about to run out the end, continue to charge / discharge can easily lead to "overcharge or over discharge the battery voltage and over current disasters such as consequences, particularly for lithium-ion battery terrible. As the battery is long over charge or over-discharge state of fatigue, produced by lithium dendrites pierce the battery separator cause permanent battery damage, and could easily cause a battery fire or explosion, security incidents are not uncommon in the country.

"Inflection point phenomenon and the lithium-ion battery life

Power lithium-ion battery "inflection point phenomenon is inevitable. Some battery manufacturers claim can be done full of shine, usually exceeding the limits of battery inflection point, the cycle life of the battery into a group discount, half the battery life is less than a monomer, thus called for the new energy automotive industry application of the main technical bottleneck is not surprising.

Practice shows that the moderate charge and discharge rate at room temperature (0.3C-1.0C) battery will have a better performance, cycle life is also president. Pure electric vehicles to try to avoid full charge up, and high rate charge / discharge, the rational use of the platform area of ​​the battery. The inflection point outside the weak point of the battery charge / discharge more than the inflection point areas on the cell damage, the full charge and full release is the root cause of battery safety and cycle shortened life expectancy.

Perverse ways and means of the objective laws of the battery frequently appeared in the electric vehicle test project, such as charge and release "theory and a variety of equilibrium theory. Some practices seemingly solved 100% of the battery SOC charge and discharge issues, but the substance is mostly based on the cost of sacrificing battery cycle life, this battery power to all "full of drained idea seems to improve the battery continued driving range, the actual and serious damage to the battery originally healthy life, to accelerate the deterioration of battery performance, make the original cycle life can reach half of the 1500-2000 times more than the single cell group can only reach the original value or even only less than 200 -300 times the life cycle.

Analysis of problem-solving way

Battery into a group factory battery consistency of how outstanding, if not the means of scientific management and take seriously the battery inflection point characteristics, the degradation phenomenon of late there will still be the battery into a set of characteristics in advance, which is why lithium-ion battery has not been able to meet the new energy vehicles performance requirements of the underlying causes.

Battery as a power vessel or electric energy carrier, the ultimate application does not mean that the best applications, the battery into a group application, you should try to take into account the inflection point effect, not overrun use, make full use of the effective energy of the battery platform. This method first glance, seems to be 11.1v 5200mah 9cells 497695-001losing a little of the remaining capacity, but it can exchange doubled to extend battery cycle life.

Battery management system (BMS) should follow the objective law of the battery itself to the rational management of the group of battery, and make full use of the battery itself inflection point features and curved platform, using reasonable means of electronic technology into a set of batteries to maximize their effectiveness, and so improve the battery pack of life is entirely possible.

The material has good solution processing

June 19 [Tue], 2012, 16:11
Recently informed from the CAS Institute of Chemistry, The Key Laboratory of Solids researchers in the study of efficient small organic molecules photovoltaic materials to obtain a series of11.1v 5200mah 9cells 43R1967
According to the researchers, the organic solar cell materials is divided into small molecules and polymer are two kinds of the highest efficiency polymer donor and fullerene receptors blends. However, the polymer molecular structure, molecular weight, purity, not sure, will bring the difference between different batches of material properties, which is likely to lead to instability of the industrial production batch in the future.

Solar cell materials and polymer materials, small organic molecules to determine the molecular structure and molecular weight, and relatively easy separation and purification, high purity, good stability of the batch preparation process. However, the development of solar cells of the small organic molecules is relatively slow, less reported in the literature of the type of material, the cell conversion efficiency was lower.

The support of the National Natural Science Foundation of China, Ministry of Science and Technology, Chinese Academy of Sciences, Key Laboratory of Organic Solids, researchers synthesized a series of DAD small organic molecules in a one-dimensional electron donor and electron acceptor fullerene derivative PC71BM total mixed preparation of small molecule cell efficiency of up to 3.7%.

The researchers have further developed a three-dimensional conjugated organic small molecule electron donors. The material has good solution processing, the isotropy of light absorption and charge transport, absorption and wide, the migration rate, etc.. The electron donor and PC71BM prepared by blending small molecule solar cells, without any post-processing, energy conversion efficiency as high as 4.3% was based on the maximum efficiency of solar cells of the same type. Related papers published over the past year, by SCI11.1v 5200mah 9cells AS10B31 < cited 45 times, and selected ESI highly cited papers and hot papers. In addition, they also developed a three-dimensional conjugated organic small molecule non-fullerene electron acceptor, the battery has been high open circuit voltage of 1.18 volts.