Fault tolerant voltage measurement method
AssigneeThe Regents of the University of Michigan
InventorsChris MI, Bing XIA
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Abstract
A fault tolerant voltage measurement method for battery management systems is proposed for reliable and prompt cell fault and sensor fault detection. The key of the method is that it correlates one voltage sensor reading with multiple cell voltages and vice versa. When a cell fault occurs, fault readings will be revealed by multiple voltage sensor readings. Similarly, when a sensor fault occurs, multiple cell voltages will be influenced. Compared with the traditional one-to-one correspondence voltage measurement, the proposed method increases the credibility of sensor/cell fault decisions. Furthermore, it does not increase the hardware cost, and is easy to be adopted in real applications.
Claims18
A method for detecting a fault condition in a string of battery cells arranged in series, comprising:
- grouping N battery cells into L groups of cells, each group of cells is comprised of a combination of two or more battery cells, each cell is associated with at least two of the L groups of cells, and each combination of battery cells is comprised of battery cells which differ from the other combination of battery cells;
- measuring voltage across each group in the L groups of battery cells using M voltage sensors, such that each voltage sensor of the M voltage sensors measures voltage across a different group of the L groups of battery cells;
- and
- determining, by a controller, a fault condition in the string of battery cells using the voltage measurements for each group in the L groups of battery cells.
A method for detecting a fault condition in a string of battery cells arranged in series, comprising:
- grouping N battery cells into L groups of cells, each group of cells is comprised of a combination of two or more battery cells and each combination of battery cells is comprised of battery cells which differ from the other combination of battery cells;
- measuring voltage across each group in the L groups of battery cells using M voltage sensors, such that each voltage sensor of the M voltage sensors measures voltage across a different group of the L groups of battery cells;
- and
- representing cell voltages for each cell in the N battery cells as a matrix, C;
- representing voltage measurements for each group in the L groups of battery cell as a matrix, V;
- representing a mapping between each voltage measurement and the battery cells whose sum corresponds to the voltage measurement in a matrix, A;
- and
- determining current cell voltages using matrix multiplication, wherein the relationship is expressed as V=AC.
A battery management system, comprising:
- N battery cells connected in series, where the N battery cells are grouped into L groups of cells, each group of cells having a combination of two or more battery cells, each cell is associated with at least two of the L groups of cells, and each combination of battery cells is comprised of battery cells which differ from the other combinations of battery cells;
- M voltage sensors electrically coupled across the N battery cells, where each voltage sensor of the M voltage sensors is configured to measure voltage across a different group of the L groups of battery cells;
- and
- a controller electrically coupled to each of the M voltage sensors and operates, in response to voltage measures from the M voltage sensors, to determine a fault condition using the voltage measurements from each group in the L groups of battery cells.
Dependencies are inferred from the claim text.