Most designers realize the importance of adding circuit protection to applications that use battery packs in order to maintain their high reliability and safety. That’s because batteries such as Lithium-ion are repeatedly charged and discharged, making them vulnerable to numerous types of harmful overvoltage, overcurrent and overtemperature conditions. As emerging new application areas extend the use of Li-ion battery packs for use in vehicles, industrial machinery and stationary power storage, continued advancements in circuit protection are already being developed.
To help designers wade through the myriad of solutions and battery regulations, we’ve developed a new Battery Pack Protection Overview white paper that presents various methods for protecting Li-ion battery packs. Since battery cells face inherent electrical, environmental and mechanical challenges when overcharged or overheated, the paper covers how best to address threats that can cause a battery cell to rupture, combust or explode. Because of the widespread use of battery packs, producers have become more safety-sensitive and are working to prevent these unwanted outcomes. Readers will find helpful regulatory testing requirements for various types of battery cells and battery packs.
The paper explains the relationship between charge and temperature, and gives readers a better understanding of the charging process for Li-ion batteries. And, it provides the important reasons why Li-ion battery cells must never be discharged below their specified minimal voltage.
As effective circuit protection solutions typically comprise a combination of several devices, this paper outlines the two most popular overvoltage and overcurrent protection methods in cell designs. It also covers the need for a second level of protection offering Bourns® Multifuse® Polymer PTC (PPTC) devices or our miniature resettable TCO devices, also known as mini-breakers, as optimal overtemperature protection solutions. For a two-fold level of overvoltage and overcurrent protection, Current Sense Resistors (CSR) are highlighted for monitoring voltage/current.