Battery control device

• US 9,685,807 B2
• Filed: 01/27/2014
• Issued: 06/20/2017
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: Vehicle Energy Japan, Inc. (Nissan Motor Co., Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: Nakao, Ryouhei, Imai, Shinji, Ohkawa, Keiichiro, Igarashi, Naoyuki, Soma, Takahiro
• Primary Examiner(s): Williams, Arun
• Assistant Examiner(s): PIGGUSH, AARON C
• Application Number:
  US14/655,371
• Publication Number:
  US 20150357852A1
• Time in Patent Office: 1,240 Days
• Field of Search: 320132, 320134, 320162, 702 63
• 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 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/24 for controlling the temperature of batteries
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Provided is a battery control device that can accurately detect a state of charge even if characteristics relating to the state of charge change as a result of battery degradation. This battery control device is provided with map data describing the correspondence relationship between an open-circuit voltage and a state of charge of the battery and outputs different state-of-charge values for the same open-circuit voltage according to the amount of elapsed time.

Claims

1. A battery control device comprising:

a first memory that stores a plurality of SOC-OCV characteristics, wherein each of the plurality of SOC-OCV characteristics indicates a relationship between an open circuit voltage (OCV), a temperature and a state of charge of battery;

a second memory that stores a plurality of relationships between a residual capacitance and the OCV;

a signal communication means that is communicatively coupled to a cell battery controller;

a voltage detector electrically connected to an assembled battery, wherein the assembled battery includes a plurality of electrically connected batteries;

a current detector electrically connected to the assembled battery that measures an electric current flowing through the assembled battery; and

a processor communicatively coupled to the first and second memory, the signal communication means, the voltage detector and the current detector;

wherein the processor;

acquires a first voltage from the voltage detector,

acquires a first current from current detector,

calculates a first OCV based on the first voltage and the first current,

determines a first residual capacity for the assembled battery based on the first current,

retrieves from the first memory a particular SOC-OCV characteristic based on the first OCV and the first residual capacity,

determining if the particular SOC-OCV characteristic has varied based on the first OCV and the first residual capacity,

selects a different SOC-OCV characteristic as a selected SOC-OCV characteristic if the particular SOC-OCV is determined to vary,

selects the particular SOC-OCV characteristic as the selected SOC-OCV characteristic if the particular is determined to not vary, and

automatically controls the charge and discharge of the assembled battery based on the selected SOC-OCV characteristic.

2. The battery control device according to claim 1,

wherein the first residual capacity is determined by integrating the electric current flowing through the battery.

3. The battery control device according to claim 1,

wherein the processor further:

calculates an internal resistance of the assembled battery, and

the process determines if the particular SOC-OCV characteristic has varied based on the internal resistance.

4. The battery control device according to claim 1, wherein the processor further:

determines a state of health of the battery based on the selected SOC-OCV characteristic, and

if that state of health of the battery has reached a predetermined degree suspends charging of the assembled battery.

5. The battery control device according to claim 4,

wherein if the state of health of the battery has not reached the predetermined degree, the process does not suspend charging of the assembled battery.

6. The battery control device according to claim 2,

wherein the process further corrects the selected SOC-OCV characteristic by a predetermined amount according to a state of health of the assembled battery.