Battery system for vehicle and control method thereof

Patent metadata

Field	Value
Publication number	US-10279700-B2
Application number	US-201715794691-A
Country	US
Kind code	B2
Filing date	Oct 26, 2017
Priority date	Nov 16, 2016
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

In a case where high-rate deterioration of a secondary battery progresses before execution of external charging by a charging device, an electronic control unit (ECU) executes an SOC adjustment process of adjusting an SOC of the secondary battery such that the SOC falls within a predetermined range. The predetermined range is a range where an expansion-contraction change of a negative electrode of the secondary battery along with charge and discharge of the secondary battery is small as compared with a case where the SOC is out of the predetermined range. After the execution of the SOC adjustment process, the ECU executes a process of moderating the high-rate deterioration so as to moderate the high-rate deterioration, and then executes the external charging.

First claim

What is claimed is:

1. A battery system for a vehicle, comprising:
a secondary battery provided in the vehicle;
a charging device configured to charge the secondary battery by a power supply provided outside the vehicle; and
an electronic control unit configured to:
(i) control charge and discharge of the secondary battery;
(ii) execute a state of charge adjustment process of adjusting a state of charge of the secondary battery such that the state of charge falls within a predetermined range, the state of charge adjustment process being executed when deterioration of the secondary battery progresses before the secondary battery is charged by the charging device, the deterioration of the secondary battery being deterioration in which an internal resistance of the secondary battery increases along with a deviation of a salt concentration distribution in the secondary battery due to the charge and discharge of the secondary battery, the predetermined range being a range where an expansion-contraction change of a negative electrode of the secondary battery along with the charge and discharge of the secondary battery is small as compared with a case where the state of charge is out of the predetermined range;
(iii) execute a first process of controlling the charge and discharge of the secondary battery, after executing the state of charge adjustment process, such that either one of an over-discharge current, an absolute value of which is larger than a first threshold, and an overcharge current, an absolute value of which is larger than a second threshold, flows through the secondary battery;
(iv) execute a second process of controlling the charge and discharge of the secondary battery such that a different one of the over-discharge current and the overcharge current from the first process flows through the secondary battery, when the deterioration further progresses due to execution of the first process;
(v) execute a third process of controlling the charge and discharge of the secondary battery such that the same current as the one flowing in the first process, out of the over-discharge current and the overcharge current, flows through the secondary battery, when the deterioration is moderated by the execution of the first process; and
(vi) charge the secondary battery by the charging device, after the execution of the second or third process.

2. The battery system for the vehicle, according to claim 1 , wherein
the electronic control unit is configured to:
(i) execute the second process based on determination that the deterioration further progresses by the execution of the first process, when the internal resistance of the secondary battery is increased by the execution of the first process; and
(ii) execute the third process based on determination that the deterioration is moderated by the execution of the first process, when the internal resistance of the secondary battery is decreased by the execution of the first process.

3. The battery system for the vehicle, according to claim 1 , wherein
a lower limit of the predetermined range is a state of charge of 40 percentage or more, and an upper limit of the predetermined range is a state of charge of 70 percentage or less.

4. The battery system for the vehicle, according to claim 1 , wherein
(i) the over-discharge current includes at least one set of a current pattern constituted by a first discharging current pulse and a first charging current pulse having the same quantity of electricity;
(ii) the overcharge current includes at least one set of a current pattern constituted by a second charging current pulse and a second discharging current pulse having the same quantity of electricity; and
(iii) an absolute value of the first discharging current pulse is larger than the first threshold, an absolute value of the first charging current pulse is smaller than the second threshold, an absolute value of the second charging current pulse is larger than the second threshold, and an absolute value of the second discharging current pulse is smaller than the first threshold.

5. A control method of a battery system for a vehicle, the battery system including a secondary battery provided in the vehicle, and a charging device configured to charge the secondary battery by a power supply provided outside the vehicle, the control method comprising:
(i) executing a state of charge adjustment process of adjusting a state of charge of the secondary battery such that the state of charge falls within a predetermined range, the state of charge adjustment process being executed when deterioration of the secondary battery progresses, before the secondary battery is charged by the charging device, the deterioration of the secondary battery being deterioration in which an internal resistance of the secondary battery increases along with a deviation of a salt concentration distribution in the secondary battery due to charge and discharge of the secondary battery, the predetermined range being a range where an expansion-contraction change of a negative electrode of the secondary battery along with the charge and discharge of the secondary battery is small as compared with a case where the state of charge is out of the predetermined range;
(ii) executing a first process of controlling the charge and discharge of the secondary battery, after executing the state of charge adjustment process, such that either one of an over-discharge current, an absolute value of which is larger than a first threshold, and an overcharge current, an absolute value of which is larger than a second threshold, flows through the secondary battery;
(iii) executing a second process of controlling the charge and discharge of the secondary battery such that a different one of the over-discharge current and the overcharge current from the first process flows through the secondary battery, when the deterioration further progresses due to execution of the first process;
(iv) executing a third process of controlling the charge and discharge of the secondary battery such that the same current as the one flowing in the first process, out of the over-discharge current and the overcharge current, flows through the secondary battery, when the deterioration is moderated by the execution of the first process; and
(v) charging the secondary battery by the charging device after the execution of the second or third process.

Assignees

• Toyota Motor Co Ltd

Inventors

• Takebayashi Yoshitomo
• Ito Nobukiyo

Classifications

• B60L2240/547

  Voltage · CPC title

• B60L2240/549

  Current · CPC title

• B60L11/14

  Operations & Transport · mapped topic

• B60L11/12

  Operations & Transport · mapped topic

• H01M10/052

  Li-accumulators · CPC title