Battery state determination device

Patent metadata

Field	Value
Publication number	US-9880225-B2
Application number	US-201414782778-A
Country	US
Kind code	B2
Filing date	Mar 13, 2014
Priority date	Apr 12, 2013
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

This battery state determination device ( 10 ) is provided with: a voltage detection unit ( 13 ) that detects the voltage (V) of a rechargeable battery (M) to be evaluated; a current detection unit ( 12 ) that detects the current of the rechargeable battery (M); a charge state detection unit ( 11 ) that detects the state of charge (SOC) of the rechargeable battery (M); and a determination unit ( 11 ) configured so as to calculate the absolute value of the voltage gradient (G), which indicates the change in voltage with respect to the discharge amount (Ah), when the state of charge (SOC) of the rechargeable battery (M) is less than 40%, compare the absolute value of the voltage gradient (G) to a pre-set upper limit value (Gmax), and, when the absolute value of the voltage gradient (G) is greater than the upper limit value (Gmax), determine that a small short circuit has occurred in the rechargeable battery (M).

First claim

The invention claimed is:

1. A battery state determination device comprising:
a voltage detector that detects a voltage value of a rechargeable battery that is subject to determination;
a current detector that detects a current value of the rechargeable battery;
a charge state detector that detects a state of charge of the rechargeable battery; and
a determination unit configured to calculate an absolute value of a voltage gradient that indicates a voltage change amount relative to a discharge amount when a state of charge of the rechargeable battery is less than 40%, compare the absolute value of the voltage gradient with a predetermined upper limit value, and determine that a micro-short circuit has occurred in the rechargeable battery when the absolute value of the voltage gradient is larger than the upper limit value.

2. The battery state determination device according to claim 1 , wherein the upper limit value of the absolute value of the voltage gradient includes a plurality of upper limit values respectively set for ranges divided from a range in which the state of charge is less than 40%, and the upper limit values are set to be larger as the corresponding state of charge range becomes smaller.

3. The battery state determination device according to claim 1 , wherein the determination unit is configured to calculate an absolute value of a voltage gradient that indicates a voltage change amount relative to a discharge amount when the state of charge of the rechargeable battery is in the range of 0% or greater and 10% or less, compare the absolute value of the voltage gradient with a predetermined upper limit value, and determine that a micro-short circuit has occurred in the rechargeable battery when the absolute value of the voltage gradient is larger than the upper limit value.

4. The battery state determination device according to claim 2 , wherein the determination unit is configured to calculate an absolute value of a voltage gradient that indicates a voltage change amount relative to a discharge amount when the state of charge of the rechargeable battery is in the range of 0% or greater and 10% or less, compare the absolute value of the voltage gradient with a predetermined upper limit value, and determine that a micro-short circuit has occurred in the rechargeable battery when the absolute value of the voltage gradient is larger than the upper limit value.

Assignees

• Primearth Ev Energy Co Ltd
• Toyota Motor Co Ltd

Inventors

• KOBA Daisuke
• Takeda Sachio
• Ichikawa Koichi
• Takahashi Yasuhiro
• Mitsui Masahiko

Classifications

• H02J7/82

  Control of state of charge [SOC] · CPC title

• G01R31/3842 Primary

  combining voltage and current measurements · CPC title

• G01R19/12

  Measuring rate of change · CPC title

• G01R31/3648

  comprising digital calculation means, e.g. for performing an algorithm · CPC title

• H01M10/44

  Methods for charging or discharging (circuits for charging H02J7/00) · CPC title