Battery remaining capacity measuring apparatus suitable for hybrid car

• US 6,201,373 B1
• Filed: 04/21/2000
• Issued: 03/13/2001
• Est. Priority Date: 05/26/1999
• Status: Expired due to Term

• Current Assignee: Yazaki Corporation
• Original Assignee: Yazaki Corporation
• Inventors: Saigo, Tsutomu, Arai, Youchi, Enomoto, Michito
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/556,688
• Time in Patent Office: 326 Days
• Field of Search: 320/132, 320/149, 324/426, 324/427, 324/428, 324/433, 429/90
• US Class Current: 320/132
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/54 Transmission for changing ratio
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/903 having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/907 Electricity storage, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/917 with transmission for changing gear ratio

Abstract

A remaining capacity measuring apparatus of this invention operates as follows. A current value and a voltage value from a current sensor and a voltage sensor respectively provided in a battery connected to a hybrid mechanism portion are sampled every 1 millisecond. Each time when eight pairs (N1) of this current value data and voltage value data are collected, the current values and voltage values are each averaged. When 100 pairs (N2) of the average current values and the average voltage values are obtained, the 100 pair data are plotted on a voltage-current coordinate system. A correlation between the current and voltage is obtained based on the plural data plotted on this coordinate system. When a strong negative correlation is indicated, an approximate line indicating a relation between the voltage and current is obtained. By substituting a predetermined current value for this line, a voltage value is defined and a value corresponding to this voltage value is regarded as a current remaining capacity.

Claims

1. A battery remaining capacity measuring apparatus comprising:

a voltage sensor for detecting a terminal voltage of a battery connected to a load;

a current sensor for detecting a current flowing from the battery to the load;

a collecting means for collecting a voltage value detected by the voltage sensor and a current value detected by the current sensor every predetermined time;

a first determining means for determining whether or not a predetermined number of pairs of the voltage values and the current values are collected;

a processing means for when the predetermined number of the plural pairs are collected, averaging the voltage values and the current values respectively so as to obtain a pair of an average voltage value and average current value and repeating the processing for obtaining the pair of the average voltage value and average current value;

a second determining means for determining whether or not the processing by the processing means is continued in the shortest time from beginning of discharge from the battery to termination thereof;

a means for when it is determined that the processing by the processing means is continued in the shortest time, obtaining a correlation value between voltage and current based on plural pairs of the average voltage values and the average current values;

a means for when the correlation value indicates a stronger correlation than a predetermined level, obtaining an approximate line on current-voltage coordinate system based on the plural pairs of the average voltage values and the average current values; and

an estimating means for estimating a remaining capacity of the battery by obtaining a corresponding voltage value based on the approximate line and a preliminarily set current value.

2. A battery remaining capacity measuring apparatus according to claim 1 wherein the load is hybrid mechanism for assisting a traveling with an engine and a motor and the battery is electrically connected to the motor.

3. A battery remaining capacity measuring apparatus according to claim 1 wherein where the shortest time is T_dc(second), a collecting period by the collecting means is T_sa(second) and the predetermined number of pairs of the voltage values and the current values is N1, a quantity N2 of the plural pairs of the average voltage values and the average current values is obtained according to a following equation;

4. A battery remaining capacity measuring apparatus according to claim 3 wherein the shortest time T_dc is 0.8 seconds.

5. A battery remaining capacity measuring apparatus according to claim 4 wherein the collecting period T_sa is 0.001 seconds and the N1 is 8.