22 Dec 2011

Last week, this blog explored several common factors that manufacturers should be aware of from a safety standpoint when using lithium batteries: external short circuit and excessive discharge of charge current. But what other factors remain?  As part of this ongoing blog series, today’s entry will explore the next common factor: pole reversal.

Pole Reversal
Pole reversal can take place in battery stacks that consist of multiple cells connected in series. It is important to make sure that the cells in a multi-cell battery stack are well matched. Otherwise, the weakest cell could risk being heavily discharged and forced to reverse its poles. What happens if this occurs? In essence, the cell would be charged by the other cells when they are still in the process of being discharged. Multi-cell battery stacks usually have a cell-balancing function that distributes the current between the cells in a suitable manner. If the battery stack is fitted with low voltage protection, this may help to prevent pole reversal.

For more information about battery testing, please visit intertek.com/energy-storage/. Next week’s blog will take a closer look at the charging primary batteriesand insufficient charge control of rechargeable batteries.

What other questions or comments do you have around lithium-based batteries? Please leave a comment below and one our experts will respond.

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