Method for detecting battery thermal events via battery pack isolation monitoring
First Claim
1. A method of detecting and responding to a cell failure of at least one cell of a plurality of cells comprising a battery pack, the method comprising the steps of:
- periodically monitoring an electrical isolation resistance of said battery pack;
comparing said electrical isolation resistance to a preset resistance value;
determining when said electrical isolation resistance falls below said preset resistance value, wherein said electrical isolation resistance falling below said preset resistance value is indicative of said cell failure;
monitoring a battery pack temperature;
determining when said battery pack temperature exceeds a preset temperature;
determining if said electrical isolation resistance falling below said preset resistance occurs within a preset time period of said battery pack temperature exceeding said preset temperature; and
performing a predetermined cell failure response if said electrical isolation resistance falling below said preset resistance value occurs within said preset time period of said battery pack temperature exceeding said preset temperature.
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Abstract
A method for detecting cell failure within a battery pack based on variations in the measured electrical isolation resistance of the battery pack is provided. The method includes the steps of monitoring the isolation resistance; determining when the isolation resistance falls below a preset value; and performing a predetermined response when the isolation resistance falls below the preset value. The method may include additional steps such as (i) determining how long the isolation resistance remains below the preset value; (ii) determining the rate of change in the isolation resistance; (iii) determining how long it takes for the electrical isolation resistance to recover; (iv) determining when the isolation resistance falls below a third preset value, wherein this step is performed after the isolation resistance recovers to greater than the second preset value; and (v) monitoring for a secondary effect associated with cell failure.
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Citations
12 Claims
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1. A method of detecting and responding to a cell failure of at least one cell of a plurality of cells comprising a battery pack, the method comprising the steps of:
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periodically monitoring an electrical isolation resistance of said battery pack; comparing said electrical isolation resistance to a preset resistance value; determining when said electrical isolation resistance falls below said preset resistance value, wherein said electrical isolation resistance falling below said preset resistance value is indicative of said cell failure; monitoring a battery pack temperature; determining when said battery pack temperature exceeds a preset temperature; determining if said electrical isolation resistance falling below said preset resistance occurs within a preset time period of said battery pack temperature exceeding said preset temperature; and performing a predetermined cell failure response if said electrical isolation resistance falling below said preset resistance value occurs within said preset time period of said battery pack temperature exceeding said preset temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification