Battery management system and method

• US 9,455,580 B2
• Filed: 07/02/2014
• Issued: 09/27/2016
• Est. Priority Date: 08/01/2013
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Mei, Ying, Mao, Saijun, Wu, Huiqing, Wiegman, Herman Lucas Norbert, Huang, Qunjian
• Primary Examiner(s): Diao, M'Baye
• Application Number:
  US14/321,935
• Publication Number:
  US 20150035490A1
• Time in Patent Office: 818 Days
• Field of Search: 320/118, 320/119
• US Class Current: 1/1
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A battery system has a battery module including a number M of series-connected batteries. The battery system is further provided with a number N (1<N≦M) of charge equalizers, each of which once connected to a battery, causes the battery to be charged and/or discharged to achieve charge equalization. A control device is configured to determine for each battery if it requires charge equalization based on a state of charge (SOC) of the battery, compare a number L of the batteries that require charge equalization and the number M, and based on the comparison result, cause the battery system to be shut down, or the one or more batteries that require charge equalization to be connected to corresponding charge equalizers. A selective switch module is used for connecting the one or more batteries that require charge equalization to corresponding charge equalizers, respectively.

Claims

1. A battery system, comprising:

a number M of battery cells connected in series;

a number N of charge equalizers, each of which, once connected to a battery cell, causes the battery cell to be charged and/or discharged for achieving charge equalization, wherein 1<

N≦

M;

a control device configured to;

determine if one or more battery cells require charge equalization based on a state of charge (SOC) of each battery cell,

compare a number L of the battery cells that require charge equalization and the number N of charge equalizers, and

based on the comparison result, cause the battery system to be shut down, or cause the one or more battery cells that require charge equalization to be connected to corresponding charge equalizers; and

a selective switch module for connecting the one or more battery cells that require charge equalization to corresponding charge equalizers, respectively.

2. The battery system of claim 1, wherein a number of the battery cells are connected in parallel.

3. The battery system of claim 1, wherein each of the battery cells is coupled with a sensor for measuring voltage across each battery cell.

4. The battery system of claim 1, wherein the control device is configured to determine that a battery cell requires charge equalization if the SOC of the battery cell is not within a predefined range.

5. The battery system of claim 1, wherein the control device is configured to cause the battery system to be shut down if L>

N and cause the battery cells that require charge equalization to be connected to corresponding charge equalizers if L≦

N.

6. The battery system of claim 5, wherein the control device is configured to rank the L battery cells in a descending order of how much they require charge equalization and connect the L battery cells to the charge equalizers in the descending order, if L≦

N.

7. The battery system of claim 1, wherein the charge equalizer comprises one or more active semiconductor switches, and one or more passive devices.

8. The battery system of claim 1, wherein the switch module comprises one or more selected from the group consisting of metal-oxide power semiconductor transistors, bipolar junction transistors, metal-oxide-semiconductor field-effect transistors, insulated gate bipolar transistors, and relays.

9. The battery system of claim 1, wherein the control device is selected from the group consisting of microprocessors, application specific integrated circuits, digital signal processors, field programmable gate arrays and their combinations.

10. The battery system of claim 1, wherein the switch module comprises one or more selected from the group consisting of metal-oxide power semiconductor transistors, bipolar junction transistors, metal-oxide-semiconductor field-effect transistors, insulated gate bipolar transistors, and relays.

11. The battery system of claim 1, wherein the control device is selected from the group consisting of microprocessors, application specific integrated circuits, digital signal processors, field programmable gate arrays and their combinations.

12. A method comprising:

providing a number M of battery cells connected in series and a number N of charge equalizers, wherein 1<

N≦

M; and

configuring a control unit to;

determine if one or more battery cells require charge equalization based on a state of charge (SOC) of each battery cell;

compare a number L of battery cells that require charge equalization and the number N of the charge equalizers; and

based on the comparison result, shut down the battery cells, or connect the L battery cells that require charge equalization to L charge equalizers to cause the battery cells to be charged and/or discharged for achieving charge equalization.

13. The method of claim 12, wherein a battery cell is determined as requiring charge equalization if the SOC of the battery cell is not within a predefined range.

14. The method of claim 12, wherein the control unit is further configured to shut down the battery cells if L>

N, and connect L battery cells that require charge equalization to L charge equalizers, respectively, if L<

N.

15. The method of claim 14, wherein if L≦

N, further comprising configuring the control unit to rank the L battery cells that require charge equalization in a descending order of how much they require charge equalization, and the L battery cells that require charge equalization are connected to L charge equalizers respectively in the descending order.

16. A battery system, comprising:

a number M of battery cells connected in series;

a number N of charge equalizers, each of which, once connected to a battery cell, causes the battery cell to be charged and/or discharged for achieving charge equalization, wherein 1<

N≦

M;

at least one selective switch module for connecting a battery cell that requires charge equalization to a charge equalizer; and

a control device configured to;

determine if one or more battery cells require charge equalization based on a state of charge (SOC) of each battery cell,

compare a number L of the battery cells that require charge equalization with the number N of charge equalizers,

cause the battery system to be shut down if L>

N, and

cause the one or more battery cells that require charge equalization to be connected to corresponding charge equalizers if L≦

N.

17. The battery system of claim 16, wherein a number of the battery cells are connected in parallel.

18. The battery system of claim 16, wherein each of the battery cells is coupled with a sensor for measuring voltage across each battery cell.

19. The battery system of claim 16, wherein the control device is configured to determine that a battery cell requires charge equalization if the SOC of the battery cell is not within a predefined range.

20. The battery system of claim 16, wherein the charge equalizer comprises one or more active semiconductor switches, and one or more passive devices.