Show CartWhile 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.
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.batterygiant.com
Stay tuned next week when we examine battery packs for portable devices.