I see that in the US there is yet another issue with the batteries in self balancing scooters (hoverboards) resulting in a large scale recall, somewhere over 500,000 is a figure being widely banded about. The problem is with scooters made before a new standard was introduced, which seems to be a boost for all those associated with the generation of industry standards.
Why the problem with batteries in these particular devices? After all, the technology is in effect the same as that used in your smartphone. Think of all the millions of hours of safe, reliable use the batteries in those devices have clocked up. The reality is that there is a big difference between the single cell battery typically used in smartphones and the multi cell packs designed for other applications.
Often it is the way cells are packaged into batteries, and then the enclosure in which they are located, that is overlooked at the design stage. Just assuming that you can link multiple cells into a series and/or parallel arrangements and multiply the cell level performance accordingly is a potential problem in the making. Add to this enclosing the battery in a sealed compartment with little or no air movement, and a high discharge rate, the risk of battery failure rises to a point that is unacceptable.
There is nothing inherently wrong with multi cell batteries. Provided the cells chosen are capable of the required discharge rate, allowances made for de-rating as dictated by the way the battery is housed, a properly designed battery will provide reliable performance over the projected lifetime in a safe and user friendly manner.
Expecting your equipment designer to be a battery application expert is a big ask, especially with all the other details that need to be addressed. Having access to an independent battery expert will provide a cost effective solution to help avoid those common, and not so common, battery design and use errors.
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