Battery State Judging Method, And Battery State Judging Device

• US 20090171600A1
• Filed: 12/12/2006
• Published: 07/02/2009
• Est. Priority Date: 12/14/2005
• Status: Active Grant

• Current Assignee: Shin-Kobe Electric Machinery Company Limited (Resonac Holdings Corp.)
• Original Assignee: Shin-Kobe Electric Machinery Company Limited (Resonac Holdings Corp.)
• Inventors: Machiyama, Yoshiaki
• Granted Patent: US 7,962,300 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: F02D 2200/503 Battery correction, i.e. corrections as a function of the state of the battery, its output or its type
• CPC Class Codes: F02N 11/08 Circuits or control means specially adapted for starting of engines
• CPC Class Codes: F02N 11/0862 characterised by the electrical power supply means, e.g. battery
• CPC Class Codes: F02N 11/10 Safety devices F02N11/08 takes precedence
• CPC Class Codes: F02N 2200/063 Battery voltage
• CPC Class Codes: F02N 2200/14 said parameter being related to wear of starter or other components, e.g. based on total number of starts or age
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/379 for lead-acid batteries
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H01M 10/06 Lead-acid accumulators semi-lead accumulators H01M10/20
• 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: Y02E 60/10 Energy storage using batteries

Abstract

A battery state judging method is provided capable of properly judging a state of a lead-acid battery by measuring voltages without measuring currents. A state of the battery is judged by obtaining, in advance, a DC internal resistance r₀ of a same type battery in a new and fully-charged state; calculating, in advance, a load R [R=r₀×Vst₀/(OCV₀−Vst₀)] at an engine starting time (S112) from an open-circuit voltage OCV₀ (S104) and a lowest voltage Vst₀ (S108) at the engine starting time, both measured when the loaded battery is in a new and fully-charged state, and the DC internal resistance r₀; calculating a DC internal resistance r [(r=R/(OCV−Vst)/Vst)] of the loaded battery from an open-circuit voltage OCV (S104) and a lowest voltage Vst (S108), both measured when the loaded battery is in a deteriorated/insufficiently-charged state, and the load R; and comparing r and r₀.

Claims

1. A battery state judging method of a lead-acid battery loaded on a vehicle, comprising the steps of:

obtaining, in advance, a DC internal resistance r₀ of a lead-acid battery in a substantially non-deteriorated and fully-charged state;

calculating, in advance, a load R imposed at an engine starting time, using a following Equation (1), from an open-circuit voltage OCV₀ and a lowest voltage Vst₀ at the engine starting time, both measured when the lead-acid battery is in a substantially non-deteriorated and fully-charged state, and the DC internal resistance r₀;

calculating a DC internal resistance r of the lead-acid battery, using a following Equation (2), from an open-circuit voltage OCV and a lowest voltage Vst at an engine starting time, both measured when the lead-acid battery is in a deteriorated or insufficiently-charged state, and the calculated load R imposed at the engine starting time; and

judging a state of the lead-acid battery by comparing the DC internal resistance r with the DC internal resistance r₀.

R=r₀×

Vst₀/(OCV₀−

Vst₀) 

 

(1)

r=R×

(OCV−

Vst)/Vst 

 

(2)

2. The battery state judging method according to claim 1, wherein, in the step of judging a state of the lead-acid battery, a deteriorated state judging coefficient alpha represented as a value of the DC internal resistance r to that of the DC internal resistance r₀ is calculated, and a state of health (SOH) of the lead-acid battery is calculated from a predetermined correspondence relationship between a deteriorated state judging coefficient alpha and a SOH of the lead-acid battery.

3. The battery state judging method according to claim 2, wherein, in the step of judging a state of the lead-acid battery, it is judged that replacement of the lead-acid battery is required when the deteriorated state judging coefficient alpha represented as a value of the DC internal resistance r to that of the DC internal resistance r₀ is not less than a predetermined value.

4. A battery state judging apparatus that judges a state of a lead-acid battery loaded on a vehicle, comprising:

a storing means which stores, in advance, a DC internal resistance r₀ of a lead-acid battery obtained in a substantially non-deteriorated and fully-charged state;

an open-circuit voltage measuring means which measures an open-circuit voltage of the lead-acid battery;

a lowest voltage measuring means which measures a lowest voltage at an engine starting time of the lead-acid battery;

a load calculating means which calculates a load R imposed at an engine starting time, using a following Equation (1), from an open-circuit voltage OCV₀ measured by the open-circuit voltage measuring means and a lowest voltage Vst₀ at the engine starting time measured by the lowest voltage measuring means, both measured when the lead-acid battery is in a substantially non-deteriorated and fully-charged state, and the DC internal resistance r₀ stored in the storing means;

a DC internal resistance calculating means which calculates a DC internal resistance r of the lead-acid battery, using a following Equation (2), from an open-circuit voltage OCV measured by the open-circuit voltage measuring means and a lowest voltage Vst at an engine starting time measured by the lowest voltage measuring means, both measured when the lead-acid battery is in a deteriorated or insufficiently-charged state, and the load R imposed at the engine starting time calculated by the load calculating means; and

a state judging means which judges a state of the lead-acid battery by comparing the DC internal resistance r calculated by the DC internal resistance calculating means with the DC internal resistance r₀ stored in the state storing means.

R=r₀×

Vst₀/(OCV₀−

Vst₀) 

 

(1)

r=R×

(OCV−

Vst)/Vst 

 

(2)

5. The battery state judging apparatus according to claim 4, wherein the storing means further stores, in advance, a map or expression showing a correspondence relationship between a deteriorated state judging coefficient alpha represented as a value of the DC internal resistance r to that of the DC internal resistance r₀ and a SOH of the lead-acid battery, and wherein the state judging means calculates the deteriorated state judging coefficient alpha, and calculates the SOH from the correspondence relationship between a deteriorated state judging coefficient alpha and a SOH of the lead-acid battery according to the map or expression stored in the storing unit.

6. The battery state judging apparatus according to claim 5, wherein the state judging means judges that replacement of the lead-acid battery is required when the deteriorated state judging coefficient alpha represented as a value of the DC internal resistance r to that of the DC internal resistance r₀ is not less than a predetermined value.

7. The battery state judging apparatus according to claim 5, wherein the load calculating means makes the storing means store the calculated load R imposed at the engine starting time, and wherein the DC internal resistance calculating means calculates the DC internal resistance r of the lead-acid battery, using the Equation (2), from the open-circuit voltage OCV measured by the open-circuit voltage measuring means and the lowest voltage Vst at the engine starting time measured by the lowest voltage measuring means, both measured when the lead-acid battery is in a deteriorated or insufficiently-charged state, and the load R imposed at the engine starting time calculated by the load calculating means.

8. The battery state judging apparatus according to claim 7, wherein the storing unit is a nonvolatile memory.

9. The battery state judging apparatus according to claim 4, wherein the DC internal resistance r₀ stored in the storing means is obtained from a relationship equation of V=−

r₀×

I+OCV₀ standing up between a voltage V and a current I, which holds when a lead-acid battery (open-circuit voltage OCV₀) in a non-deteriorated and fully-charged state of the same type as the lead-acid battery loaded on the vehicle is discharged at a plurality of current values.

10. The battery state judging apparatus according to claim 4, wherein the load calculating means judges, when the number of times of the engine starting is less than 5 and the open-circuit voltage OCV₀ exceeds 12.5V, that the lead-acid battery is in the substantially non-deteriorated and fully-charged state and calculates the load R imposed at the engine starting time.