BATTERY PACK

• US 20120276440A1
• Filed: 04/25/2011
• Published: 11/01/2012
• Est. Priority Date: 04/25/2011
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Takagi, Masaru, Ishishita, Teruo, Nishi, Yuji, Kaita, Keiji
• Granted Patent: US 8,647,765 B2
• Time in Patent Office: Days
• US Class Current: 429/158
• 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 50/64 Constructional details of batteries specially adapted for electric vehicles
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/20 having different nominal voltages
• 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: H01M 10/4207 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 6/42 Grouping of primary cells into batteries H01M6/40 takes precedence
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y10T 29/4978 Assisting assembly or disassembly

Abstract

A battery pack has a plurality of assembled batteries connected in parallel. Each of the assembled batteries has a plurality of cells connected electrically. A circulating current in each of the assembled batteries is calculated from an open circuit voltage of the assembled battery that varies according to the number of the cells connected in series, a value indicating a charge state of the assembled battery that varies according to the number of the cells connected in parallel, and an internal resistance of the assembled battery. The number of the cells connected in parallel and the number of the cells connected in series in each of the assembled batteries are numbers determined under the condition that the circulating current should not exceed an allowable current value for the assembled battery.

Claims

1. A battery pack comprising a plurality of assembled batteries connected in parallel,

wherein each of the assembled batteries has a plurality of cells connected electrically,

a circulating current in each of the assembled batteries is calculated from an open circuit voltage of the assembled battery, the open circuit voltage varying according to the number of the cells connected in series, a value indicating a charge state of the assembled battery, the value varying according to the number of the cells connected in parallel, and an internal resistance of the assembled battery, and

the number of the cells connected in parallel and the number of the cells connected in series in each of the assembled batteries are numbers determined under the condition that the circulating current should not exceed an allowable current value for the assembled battery.

2. The battery pack according to claim 1, wherein a power of the battery pack is a power higher than a required power and is used for calculating the circulating current.

3. The battery pack according to claim 1, wherein the value indicating the charge state lies between an upper limit value and a lower limit value used in charge and discharge control of the assembled battery.

4. The battery pack according to claim 1, wherein each of the assembled batteries outputs energy for use in running of a vehicle.

5. The battery pack according to claim 2, wherein each of the assembled batteries outputs energy for use in running of a vehicle, and

the required power is a power appropriate for a preset running pattern of the vehicle.

6. A method of manufacturing a battery pack having a plurality of assembled batteries connected in parallel, each of the assembled batteries including a plurality of cells, the method comprising:

a first step of calculating a circulating current in each of the assembled batteries from an open circuit voltage of the assembled battery, the open circuit voltage varying according to the number of the cells connected in series, a value indicating a charge state of the assembled battery, the value varying according to the number of the cells connected in parallel, and an internal resistance of the assembled battery;

a second step of determining the number of the cells connected in parallel and the number of the cells connected in series in each of the assembled batteries under the condition that the circulating current should not exceed an allowable current value for the assembled battery; and

a third step of assembling each of the assembled batteries by using the cells, the number of the cells being the number determined in the second step.

7. The method of manufacturing the battery pack according to claim 6, wherein a power of the battery pack is a power higher than a required power and is used for calculating the circulating current.

8. The method of manufacturing the battery pack according to claim 6, wherein the value indicating the charge state lies between an upper limit value and a lower limit value used in charge and discharge control of the assembled battery.

9. The method of manufacturing the battery pack according to claim 6, wherein each of the assembled batteries outputs energy for use in running of a vehicle.

10. The method of manufacturing the battery pack according to claim 7, wherein each of the assembled batteries outputs energy for use in running of a vehicle, and

the required power is a power appropriate for a preset running pattern of the vehicle.