Rechargeable battery management

• US 8,531,160 B2
• Filed: 08/11/2010
• Issued: 09/10/2013
• Est. Priority Date: 08/11/2010
• Status: Active Grant

• Current Assignee: A123 Systems Incorporated
• Original Assignee: A123 Systems Incorporated
• Inventors: Moorhead, Brian C., Rutkowski, Brian D.
• Primary Examiner(s): DIAO, M BAYE
• Application Number:
  US12/854,274
• Publication Number:
  US 20120038322A1
• Time in Patent Office: 1,126 Days
• Field of Search: 320/136
• US Class Current: 320/136
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: B60L 58/26 by cooling
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

Systems and methods for adjusting sampling and switching rates of a battery management system are provided. For example, a rate at which different battery cells of a battery cell stack are in communication with an analog to digital converter may be adjusted in response to conditions of a battery cell.

Claims

1. A method for switching sampling of battery cells of a battery pack, comprising:

adjusting a rate at which different battery cells of a battery cell stack are in communication with an analog to digital converter, said rate adjusted in response to a condition of a battery cell, where said rate at which different battery cells of said battery cell stack are in communication with said analog to digital converter is different from a rate at which different battery cells of a second battery cell stack are in communication with a second analog to digital converter, said second battery cell stack different from said battery cell stack.

2. The method of claim 1, where communication between said different battery cells and said analog to digital converter is controlled by at least a switch.

3. A method for switching sampling of battery cells of a battery pack, comprising:

adjusting a rate at which different battery cells of a battery cell stack are in communication with an analog to digital converter, said rate adjusted in response to a condition of a battery cell, wherein the battery cells include a first cell with a first capacity and a second cell with a second capacity greater than the first capacity, wherein the first cell is switched into communication with the analog to digital converter more often than the second cell.

4. The method of claim 3, where said condition is a voltage of said battery cell.

5. The method of claim 4, where said rate is further adjusted in response to at least one of a battery cell state of charge and a temperature of a battery cell.

6. The method of claim 5, where said rate is related to a condition of a single battery cell of said battery cell stack during a selected condition.

7. A method for selectively sampling a plurality of battery cells of a battery pack, comprising:

during a first condition, switching a battery cell in the plurality of battery cells into communication with an analog to digital converter at a first rate and sampling a cell operating condition; and

during a second condition, switching the battery cell into communication with the analog to digital converter at a second rate and sampling the cell operating condition, said second rate greater than said first rate, the sampling rate adjusted by changing the switching rate.

8. The method of claim 7, wherein the first condition includes a state of charge of the battery cell between a lower state of charge threshold and a higher state of charge threshold and wherein the second condition includes a state of charge of the battery cell less than the lower state of charge threshold or greater than the higher state of charge threshold.

9. The method of claim 7, wherein the first condition includes a voltage of the battery cell between a lower voltage threshold and a higher voltage threshold and wherein the second condition includes a voltage of the battery cell less than the lower voltage threshold or greater than the higher voltage threshold.

10. The method of claim 7, wherein the first condition includes a temperature of the battery cell between a lower temperature threshold and a higher temperature threshold and wherein the second condition includes a temperature of the battery cell less than the lower temperature threshold or greater than the higher temperature threshold.

11. The method of claim 7, wherein the first condition includes a capacity of the battery cell greater than a threshold capacity and wherein the second condition includes a capacity of the battery cell less than or equal to the threshold capacity.

12. The method of claim 7, wherein the first and second conditions are based on at least one of state of charges of the plurality of battery cells, temperatures of the plurality of battery cells, voltages of the plurality of battery cells, and capacities of the plurality of battery cells.

13. A system for sampling battery cells of a battery cell stack, the system comprising:

an analog to digital converter;

a plurality of battery cells;

switching circuitry configured to switch each of said plurality of battery cells into communication with said analog to digital converter; and

a controller configured to adjust a rate at which different battery cells of said plurality of battery cells are in communication with and sampled by said analog to digital converter, the controller including controller instructions for adjusting said rate in response to instructions from a battery control module, said battery control module separate from the battery cell stack comprised of said plurality of battery cells.

14. The system of claim 13, further including controller instructions for adjusting said rate in response to at least one of a battery cell voltage, a battery cell state of charge, and a battery cell temperature.

15. The system of claim 13, further comprising at least one temperature sensor for determining a temperature of at least one cell of said plurality of battery cells.

16. The system of claim 13, where said analog to digital converter, said plurality of battery cells, said switching circuitry, and said controller are integrated into a battery cell pack.

17. The system of claim 13, where said plurality of battery cells is part of a battery pack and where said battery pack provides power to a motor of a vehicle.