Capacity adjustment apparatus for battery pack and capacity adjustment method for battery pack

• US 7,148,656 B2
• Filed: 03/16/2005
• Issued: 12/12/2006
• Est. Priority Date: 03/23/2004
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Sodeno, Tsuyoshi
• Primary Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US11/080,844
• Publication Number:
  US 20050212487A1
• Time in Patent Office: 636 Days
• Field of Search: 320/132, 320/136, 320/104, 320/120, 320/116, 180/65.2, 318/139
• US Class Current: 320/132
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/1446 in response to parameters of a vehicle
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Abstract

A control unit calculates target power to be generated based upon a bypass engaging voltage used as a reference voltage at which a capacity adjustment circuit executes a capacity adjustment, and issues a power generation command for an inverter so as to generate the target power if it is decided that the capacities of the individual cells need to be adjusted.

Claims

1. A battery pack capacity adjustment apparatus for a battery pack constituted by connecting in series a plurality of cells, comprising:

capacity adjustment circuits each provided in correspondence to one of the plurality of cells to execute a capacity adjustment by discharging the corresponding cell if a voltage at the corresponding cell exceeds a predetermined bypass engaging voltage;

a power generation device that generates power used to charge the battery pack;

a capacity adjustment decision-making device that makes a decision as to whether or not capacity adjustment needs to be executed for the battery pack;

a target power generation calculation device that calculates target power to be generated based upon the bypass engaging voltage; and

a power generation control device that issues a power generation command for the power generation device so as to generate the target power calculated by the target power generation calculation device if the capacity adjustment decision-making device determines that the capacity adjustment is necessary.

2. A battery pack capacity adjustment apparatus according to claim 1, wherein:

the power generation control device does not implement power generation restriction control on the power generation device while the power generation command for generating the target power is outputted and restricts the quantity of charge into the battery pack by implementing power generation control while the power generation command is not outputted.

3. A battery pack capacity adjustment apparatus according to claim 1, further comprising:

a correction device that corrects the target power calculated by the target power generation calculation device based upon conditions of the battery pack.

4. A battery pack capacity adjustment apparatus according to claim 3, wherein:

the battery pack conditions include at least one of;

an SOC, a temperature and an extent of degradation at the battery pack.

5. A battery pack capacity adjustment apparatus according to claim 2, wherein:

the battery pack capacity adjustment apparatus is installed in a vehicle, and

the power generation control device increases a threshold quantity for regenerated energy absorption if the target power generated by the power generation device exceeds a power generation limit quantity and would lower the threshold quantity for the regenerated energy absorption in the vehicle.

6. A battery pack capacity adjustment apparatus according to claim 1, wherein:

an SOC at which output restrictions are imposed on the battery pack is raised if the capacity adjustment decision-making device decides that the capacity adjustment is necessary.

7. A battery pack capacity adjustment apparatus for a battery pack constituted by connecting in series a plurality of cells, comprising:

capacity adjustment means, each provided in correspondence to one of the plurality of cells, for executing a capacity adjustment by discharging the corresponding cell if a voltage at the corresponding cell exceeds a predetermined bypass engaging voltage;

a power generation means for generating power used to charge the battery pack;

a capacity adjustment decision-making means for making a decision as to whether or not capacity adjustment needs to be executed for the battery pack;

a target power generation calculation means for calculating target power to be generated based upon the bypass engaging voltage; and

a power generation control means for issuing a power generation command for the power generation means so as to generate the target power calculated by the target power generation calculation means if the capacity adjustment decision-making means determines that the capacity adjustment is necessary.

8. A battery pack capacity adjustment method for adjusting capacities of a plurality of cells constituting a battery pack by using capacity adjustment circuits each provided in correspondence to one of the plurality of cells to discharge the corresponding cell if a voltage at the corresponding cell exceeds a predetermined bypass engaging voltage, comprising steps for:

making a decision as to whether or not a capacity adjustment needs to be executed for the battery pack;

calculating target power to be generated based upon the bypass engaging voltage; and

issuing a power generation command for a power generation device that generates power used to charge the battery pack so as to generate the target power if the capacity adjustment for the battery pack is determined to be necessary.