While older cell phones were powered with nickel-based batteries, most newer phones are now equipped with lithium-ion. This chemistry is preferable, as it is lightweight, offers high energy density and lasts long enough to span the typical life of the product. Plus, lithium-ion contains no toxic metals.

To obtain thin geometry, some cell phone manufacturers have switched to lithium-ion-polymer. This satisfied consumer requests for slim battery designs. In the meantime, technological advancements also made low profile lithium-ion possible. Thus, lithium-ion packs are now available in 3 mm, a profile that suits most battery designs. Lithium-ion has the advantage of lower manufacturing cost and better performance, plus it has a 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 the battery 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 of the battery into the charger or cradle does not damage the battery though overcharge. If the battery is full, no charge is applied. The battery voltage determines the need to charge.

On the negative side, lithium-ion loses charge acceptance as part of aging, even if not used. And lithium-ion batteries should not be stored for long periods.  Rather, lithium-ion batteries need to 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.

So………………………..just like when purchasing food, check the dates, and once in the refrigerator – ROTATE!

For additional information, visit www.batterygiant.com

Batteries for laptops have a unique challenge - they must be small and lightweight. In fact, the laptop battery should be invisible to the user and deliver enough power to endure a five-hour flight from Detroit to San Diego. But we know this rarely happens, as a typical laptop battery provides only about 90 minutes of service, and many of us complain of much shorter runtimes.

Computer manufacturers are hesitant to add a larger battery to the laptop because of increased battery size and weight. A recent survey indicated that, given the option of larger battery size and more weight for longer runtimes, most users would settle for the laptop battery that is being offered today. For better or worse, we have learned to accept the short runtime of a laptop battery.

Laptop batteries age more quickly than in other applications because of heat. During use, the inside temperature of a laptop rises to 45°C (113°F). The combination of high temperature and the battery’s full state-of-charge promotes cell oxidation, a condition that cannot be reversed once present. The battery’s life expectancy when operating at high temperature is half compared to a battery running at a more moderate 20°C (68°F) temperature.  Leaving the laptop battery in a parked car under the hot sun, for example, will aggravate the situation. While all batteries suffer permanent capacity loss as part of elevated temperatures, lithium-ion batteries are affected more than other batteries –  and most laptops are powered by lithium-ion batteries. The chemistry in a lithium-ion battery has a high energy density and is lightweight. Alas, there is no immediate breakthrough on the horizon of a miracle battery that would provide more power than the current electro-chemical battery.

So, as with your skin, keep the laptop battery out of the sun…………………………!

For additional information, visit www.battergiant.com

Most manufacturers of cell phones, laptops and cameras develop their own battery packs. A model change often results in a redesigned battery. The typical contact arrangements of cell phone and video camera batteries are: battery positive, negative and temperature sensor. Additional contacts may serve as control switch or battery type identifier. “Smart” batteries have extra contacts to provide state-of-charge indication and other information. Recall that there are no norms and standards for these batteries. Each manufacturer has its own design (see Battery Giant December blog posts.)

In the 1990s, however, the Smart Battery System (SBS) forum made a concerted effort to standardize on battery norms for laptops, survey equipment and medical instruments. Beside physical size, these batteries ran on a standard SMBus protocol. With miniaturizing and securing a lucrative battery replacement market, laptop manufacturers went their own way. The SMBus batteries are still widely used today for specialty instruments.

Recall that the typical battery has the inherit problem of not being able to communicate with the user, as neither weight, color, nor size provides an indication of the battery’s state-of-charge (SoC) and state-of-health (SoH). The user is at the mercy of the battery. Today’s rechargeable “smartâ€� batteries, however, are equipped with a microchip, and able to communicate with both the charger and user.

There are several types of ’smart’ batteries, each offering different complexities and costs. We have determined that the SMBus is the most complete of all of these smart battery 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 data and clock. 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 is a servant that must follow the dictates of the battery.

As with life, it’s all about having the most qualified person in charge……….

For additional information, visit www.batterygiant.com

While old battery packaging systems involved large glass jars and wooden containers, new battery packaging is smaller and sleeker.  Following World War II, portability became important, and the cylindrical cell was developed. Then, in the 1980s the button cell appeared, followed by the prismatic cell and the modern pouch cell.  Let’s examine the strengths and limitations of each of these battery packaging systems.
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The cylindrical battery cell continues to be the most widely used packaging. It is easy to manufacture, offers high energy density and provides good mechanical stability. Plus,  the cylinder has the ability to withstand high internal pressures. Typical applications are wireless communication, mobile computing, biomedical instruments, power tools and applications that do not demand ultra-small size. A minus of the cylindrical cell is its poor space utilization. Because of its fixed cell size, a battery pack must be designed around available cell sizes.

The button battery cell was developed to reduce pack size and improve stacking. Non-rechargeable battery cells are found in watches, hearing aids and memory backup.

The rechargeable button cells are mostly nickel-based and are found in older cordless telephones, biomedical devices and industrial instruments. A plus is that it is inexpensive to manufacture.  The minus is charge times of 10-16 hour and swelling if charged too rapidly. Button cells have no safety vent.

The prismatic battery cell was developed in the early 1990s to response to consumer demand for thinner geometry. Prismatic battery cells are commonly reserved for the lithium battery family. The polymer version is exclusively prismatic. The plus is that the prismatic battery cell comes in various sizes with capacities from 400mAh to 2000mAh and higher. No standard cell size exists; rather, prismatic cells are custom-made for cell phones and other high volume items. The negative attributes of the prismatic battery cell are slightly lower energy densities and higher manufacturing costs than the cylindrical cell. In addition, the prismatic cell does not provide the same mechanical stability enjoyed by the cylindrical cell.

In 1995, the pouch battery cell made a profound advancement in cell design when it used a heat-sealable foil rather than the expensive metallic enclosures and glass-to-metal electrical feed-troughs. The pouch battery cell concept allows tailoring to exact cell dimension. It makes the most efficient use of available space and achieves a battery packaging efficiency of 90 to 95 percent, the highest among battery packs. Plus, because of the absence of a metal can, the pouch pack is light. The main application is cell phones. No standardized pouch cell exists, and each manufacturer builds to a special application. The pouch battery cell is exclusively used for lithium-based batteries. Manufacturing cost is still higher than conventional systems and its reliability has not been fully proven. For additional information, visit www.battergiant.com

Stay tuned next week when we examine battery packs for portable devices…………

During the last 20 years, battery testing lagged behind other industry technologies. Ideally, a battery tester should indicate the level of battery sulfation and surface charge, as well as display how to correct the problem. This feature is not yet possible. Simply, the battery is a very difficult animal to test, short of applying a full charge, discharge and recharge.

Most battery testers in use only take cold cranking amps (CCA) and voltage readings. Capacity, the most important measurement of a battery, is unavailable. While taking the CCA battery reading alone is relatively simple, measuring the capacity is very complex and instruments offering this feature are expensive.

For years, load testers have been the standard test method for car batteries. In 1992, AC conductance, a method that simplified battery testing, appeared. Now the battery industry is experimenting with multi-model electrochemical impedance spectroscopy (EIS) in a portable version at an affordable price. The Spectro CA-12 is the first in a series of high-end battery testers capable of measuring capacity, CCA and state-of-charge (SoC) in a single, non-invasive test.

During this 30-second test, over 40 million transactions are completed. A patented algorithm analyzes the data and the final results are displayed in capacity, CCA and state-of-charge. EIS is very complex and until recently required dedicated computers and expensive laboratory equipment, not to mention chemists and engineers to interpret the readings. The hardware of a full EIS system is commonly mounted on racks and the installation runs into tens of thousands of dollars.

No battery tester solves all problems. Entry-level testers are low cost, simple to use and capable of servicing a broad range of batteries. However, these units only provide a rough indication of the battery condition. A battery tester based on EIS is four times more accurate in detecting weak batteries than AC conductance. Conventional testers often misjudge the battery on account of low state-of-charge. Many batteries are replaced when they should have been recharged, while others are given a clean bill of health when they should have been replaced.
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Like humans, batteries are complex and behavior can be difficult to predict.

According to a leading manufacturer of car batteries, factory defect amounts to less than 7 percent of car battery malfunction. This is good news for battery manufacturers, as good car battery performance is just as important to the manufacturer as it is to the consumer. Problems during the battery warranty period, for example, tarnish customer satisfaction. Plus, any service requirement during that time is recorded and the number is published in trade magazines. This data on battery performance is of great interest among prospective car and battery buyers throughout the world.

 

Car battery malfunction is seldom caused by factory defect, and is most likely caused by consumer driving habits. Low charge and acid stratification are the most common causes of battery malfunction. When cars are driven for only short distances and mostly in congested, city traffic, for example, batteries never get fully charged and sulfation occurs. This problem is more common on large luxury cars offering power-hungry auxiliary options than on the more basic models. Heavy accessory power when driving short distances prevents a periodic fully saturated charge that is so important for the longevity of a lead acid battery.

 

Tune in next week to discover what you should do to prevent this condition from taking hold of your car battery this winter.  Plus, discover ways to cope when it does happen.

 

For additional information, visit www.battergiant.com

Post-holiday storing of batteries should not be done without some thought regarding temperature and battery charging capacity. Generally speaking, the recommended storage temperature for most batteries is 15°C (59°F) plus or minus a few degrees. While lead-acid batteries must always be kept at full charge, nickel and lithium-based batteries should be stored at 40% state-of-charge (SoC). This level minimizes age-related capacity loss, yet keeps the battery in operating condition - even with some self-discharge.

 

Among the lithium-ion family of batteries, cobalt has a slight advantage over manganese (spinel) in terms of storage at elevated temperatures. Nickel-based batteries are also affected by elevated temperature, but to a lesser degree than lithium-ion batteries.

Lithium-ion batteries power most of today’s laptop computers. The battery compartment on many laptop computers rises to about 45°C (113°F) during operation. The combination of high charge level and elevated temperature presents an unfavorable condition for the battery. This explains the short lifespan of many laptop batteries.

Nickel-metal-hydride can be stored for about three years. The capacity drop that occurs during storage is permanent and cannot be reversed. Cool temperatures plus a partial charge on the battery slows this aging process. Nickel-cadmium batteries store reasonably well. Field tests revealed that NiCd batteries that were stored for five years still performed at A plus levels after priming cycles. Alkaline and lithium batteries (primary) can be stored for up to 10 years. The capacity loss is minimal.

The sealed lead-acid battery can be stored for up to two years and still perform at the A plus level as well. A periodic topping charge of these batteries, also referred to as refresh charge, is required to prevent the open cell voltage from dropping below 2.10V.

 

So, caring for batteries when they are not in use is just as important as caring for them while they are.

 

For additional information, visit www.battergiant.com