Battery Packs

Battery packs are any number of individual batteries arranged in series or parallel to provide required power to electronic devices. The most typical type of battery used in battery packs is lithium ion due to their high power density. The application of battery packs is wide ranging from phones to lawn mowers to automobiles.

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Video Transcript

In this video series we'll take a look at how battery packs are designed for a variety of different applications, we'll take an in-depth look at the “brains” that make battery packs work, the battery management system and we'll examine the physical design factors that influence the design of a battery pack such as size, shape and weight of various applications.

Lithium Ion cells currently have the largest market share of the rechargeable battery market because of their high power density.

When designing a battery pack the specific application will dictate the required voltage and current. Individual cells can be scaled up and down and used in different combinations to create output voltages and currents that meet the needs of the application. When individual cells are arranged in series the voltage adds up. When they are arranged in parallel the currents add up.

But other than just designing a battery pack to meet a required voltage and current rating, several other factors have to be considered in the design. For example, a battery pack is made up of a multiple cells. The battery's performance is optimized and the life of the battery is prolonged if all the individual cells in the battery are managed so they always have the same state of charge.

Lithium Ion batteries can be damaged if they're discharged below a certain threshold level because the internal resistance of the battery will cause the battery to heat up when it is recharged. Lithium ion cells can also be damaged if they're discharged below a certain threshold, approximately 5 percent of total capacity. If the cells are discharged below this threshold their capacity can become permanently reduced.

Lithium Ion batteries are also susceptible to damage if they're overcharged . In the worst cases, batteries are susceptible to leakage and explosion if they are overcharged so its important to have a system in place that prevents a battery from exceeding its maximum charge capacity.

To ensure a battery's charge doesn't go above or below its limits a battery management system has a safeguard device called a "dedicated Lithium-ion protector chip" or “ protector .”

For practical reasons, it's useful to have information about the current state of the battery such as state of charge or how much “juice” the battery has left as well as the state of the battery's health, since rechargeable batteries degrade after multiple charge and discharge cycles. For safety reasons, in many applications it's also important to gauge operating temperature.

All of these design factors we mentioned are typically controlled by a battery management system which serves as the “brain” of the battery pack, providing useful information and also protecting the battery from damage.

Battery Management Products

Vecture Battery Management Systems

Vecture provides design engineering and Battery Management Systems (BMS) manufacturing for the commercial/industrial, consumer, energy, medical, military, and telecommunications markets.