Short detection in battery cells

摘要

Internal shorts and other failures in lithium-ion battery cells may be detected during balancing of the battery cells. A counter may be used to detect when a battery cell is behaving differently than other battery cells by balancing more or less frequently. The counter may increment each time a battery cell is balanced to the other battery cells. A misbehaving battery cell may be flagged, when the counter exceeds a threshold value, for safety checks before an overheating event occurs. This misbehaving battery cell may be faulty due to an internal short. If the faulty battery cell is not corrected by replacement with a different battery cell or corrected by a user resetting the counter, the misbehaving battery cell may be disconnected to prevent the overheating event.

主权项

1. A method, comprising:
monitoring, by a microprocessor, a plurality of battery cells through circuitry coupled to the plurality of battery cells to monitor at least one of a voltage across at least one of the plurality of battery cells and a current through at least one of the plurality of battery cells; counting, by the microprocessor, a first number of times a first battery cell of the plurality of battery cells is out of balance with other battery cells of the plurality of battery cells, wherein the step of counting comprises determining whether the first battery cell is out of balance with the other battery cells by comparing a relative state of charge of the first battery cell with a relative state of charge of at least one of the other battery cells, wherein the relative state of charge of the first battery cell and the at least one of the other battery cells is determined based, at least in part, on the step of monitoring the plurality of battery cells; counting, by the microprocessor, a second number of times a second battery cell of the plurality of battery cells is out of balance with other battery cells of the plurality of battery cells, wherein the step of counting comprises determining whether the second battery cell is out of balance with the other battery cells by comparing a relative state of charge of the second battery cell with a state of charge of at least one of the other battery cells; and marking, by the microprocessor, the first battery cell as potentially faulty due to an internal short based, at least in part, on the first count exceeding a first threshold, wherein the first threshold, for marking the first battery cell as potentially faulty due to an internal short is based at least in part on the second count.