Analysis of several 7S lithium-ion battery protection circuits

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Analysis of several 7S lithium-ion battery protection circuits [Copy link]

Among lithium-ion battery protection IC products, only 4 cells are currently connected in series. Therefore, many engineers feel that there is too little information or a lack of ready-made product circuits to develop when designing lithium-ion battery protection circuits with more than 4 cells.
In the past two years, I have come across four or five 7-cell lithium-ion battery series protection circuits developed by other companies. Here, I use my spare time to draw them one by one for your reference, so that engineers can avoid detours.
The figure below is the schematic diagram of the first type
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The above circuit is an early version of a 7-cell series lithium-ion battery protection circuit developed by a foreign company. The protection function of the circuit is relatively reliable, and it has a simple charge balancing circuit.
However, this circuit has major disadvantages: the power consumption of the cells in 7S is uneven, and the static power consumption of the cells with lower cells is too large.
There are also some minor disadvantages: the circuit is slightly complicated, difficult to expand, and the cost is not low.
However, as an early 7S protection circuit product, its protection function is fully realized, with overcharge, over-discharge, overcurrent and short-circuit protection functions. It also has a simple charge balancing function.