BATTERY CONTROL DEVICE

• US 20200136399A1
• Filed: 09/06/2019
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Akaishi, Takayuki, Shiozumi, Yuhki
• Granted Patent: US 11,223,212 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/007186 obtained with the battery disconnected from the charge or discharge circuit
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery control device that controls a battery assembly includes a first determining unit that determines whether a voltage difference between minimum and maximum values of OCVs of battery cells constituting the battery assembly and having an SOC-OCV characteristic curve including a flat region is equal to or larger than a predetermined voltage value, a second determining unit that determines whether the OCV of each battery cell is lower than a lower-limit voltage of the flat region, or is equal to or higher than the lower-limit voltage and lower than an upper-limit voltage, or is higher than the upper-limit voltage, a controller that executes control selected from SOC raising control, SOC lowering control, and SOC keeping control of the battery cells, based on determination results of the first and second determining units, and a processor that homogenizes the SOCs of the battery cells controlled by the controller.

Claims

1. A battery control device that controls a battery assembly, the battery control device comprising:

a first determining unit configured to determine whether a voltage difference between a minimum value and a maximum value of open circuit voltages of a plurality of battery cells connected to provide the battery assembly is equal to or larger than a predetermined voltage value, each of the battery cells having an SOC-OCV characteristic curve including a flat region in which a rate of change of an open circuit voltage with respect to a power storage amount is smaller than that in an adjacent region;

a second determining unit configured to determine whether the open circuit voltage of each of the battery cells is lower than a lower-limit voltage of the flat region, or is equal to or higher than the lower-limit voltage and lower than an upper-limit voltage of the flat region, or is higher than the upper-limit voltage;

a controller configured to execute one control selected from control for raising power storage amounts of the battery cells, control for lowering the power storage amounts of the battery cells, and control for keeping the power storage amounts of the battery cells, based on results of determinations made by the first determining unit and the second determining unit; and

a processor configured to perform a process of homogenizing the power storage amounts of the battery cells controlled by the controller.

2. The battery control device according to claim 1, wherein the controller performs the control for raising the power storage amounts of the battery cells, when the first determining unit determines that the voltage difference is smaller than the predetermined value, and the second determining unit determines that the open circuit voltages of all of the battery cells are equal to or higher than the lower-limit voltage and lower than the upper-limit voltage, at a point in time at which a predetermined period has elapsed.

3. The battery control device according to claim 1, wherein the controller performs the control for raising the power storage amounts of the battery cells, when the first determining unit determines that the voltage difference is equal to or larger than the predetermined value, and the second determining unit determines that the open circuit voltage of at least one of the battery cells is equal to or higher than the upper-limit voltage, and the open circuit voltage of at least another one of the battery cells is lower than the upper-limit voltage.

4. The battery control device according to claim 1, wherein the controller performs the control for keeping the power storage amounts of the battery cells, when the first determining unit determines that the voltage difference is equal to or larger than the predetermined value, and the second determining unit determines that the open circuit voltages of all of the battery cells are lower than the lower-limit voltage or higher than the upper-limit voltage.

5. The battery control device according to claim 1, wherein the controller performs the control for lowering the power storage amounts of the battery cells, when the first determining unit determines that the voltage difference is equal to or larger than the predetermined value, and the second determining unit determines that the open circuit voltage of at least one of the battery cells is equal to or higher than the lower-limit voltage and lower than the upper-limit voltage, and the open circuit voltages of all remaining ones of the battery cells are lower than the upper-limit voltage.

6. The battery control device according to claim 5, further comprising a third determining unit configured to determine a power storage amount of a battery to which electric power discharged from the battery cells under the control for lowering the power storage amounts of the battery cells is allowed to be transferred, wherein

the controller executes the control for lowering the power storage amounts of the battery cells by transferring electric power to the battery, based on the results of determinations made by the first determining unit and the second determining unit, when the third determining unit determines that the power storage amount of the battery is equal to or smaller than a predetermined value.