Apparatus and method for simulating a battery tester with a fixed resistance load

• US 20060279288A1
• Filed: 08/21/2006
• Published: 12/14/2006
• Est. Priority Date: 11/11/2003
• Status: Active Grant

• Current Assignee: Midtronics Incorporated
• Original Assignee: Midtronics Incorporated
• Inventors: Klang, James K.
• Granted Patent: US 7,595,643 B2
• Time in Patent Office: Days
• US Class Current: 324/426
• 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 31/386 using test-loads

Abstract

A method and apparatus for simulating a battery tester with a fixed resistance load, such as a widely used Japanese load tester that rates the strength of Japanese batteries that are categorized under the Japanese Industrial Standard (JIS), are provided. This invention simulates such a device without invoking large current loads, yields familiar results, utilizes an existing database and provides more conclusive testing. The method includes estimating a battery load test voltage as a function of a measured battery dynamic parameter, an open circuit voltage, the load resistance value of the load tester and the battery temperature. A bounceback voltage (BBV) of the battery is also predicted. The BBV, load voltage and battery temperature are utilized to rate the strength of the battery. Also, to improve the accuracy of test results for a substantially discharged battery, one embodiment projects the results of recharging discharged batteries without actually doing so.

Claims

1. A battery testing method that is based on battery rating standards, the method comprising:

(a) measuring a dynamic parameter of the battery;

(b) obtaining an open circuit voltage of the battery;

(c) obtaining a temperature of the battery;

(d) setting a predetermined load resistance value;

(e) estimating a full charge dynamic parameter and a full charge open circuit voltage of the battery;

(f) estimating a load voltage of the battery as a function of the estimated charged battery dynamic parameter, the charged open circuit voltage of the battery, the load resistance value and the temperature of the battery;

(g) predicting a full charge bounceback voltage; and

(h) utilizing the full charge bounceback voltage and the load voltage to rate the strength of the battery.

2. The method of claim 1 wherein setting the predetermined load resistance value in step (d) comprises setting the load resistance value to be appropriate for a load tester being simulated.

3. The method of claim 1 wherein the obtaining the temperature of the battery in step (c) comprises receiving the temperature of the battery as an input provided by a user.

4. The method of claim 1 wherein the obtaining the temperature of the battery in step (c) comprises receiving the temperature of the battery as an input from a temperature sensor.

5. The method of claim 1 wherein the dynamic parameter measurement in step (a) comprises determining a response of the battery to an applied current pulse.

6. The method of claim 1 wherein the measured battery dynamic parameter value is battery conductance.

7. The method of claim 1 wherein the measured battery dynamic parameter value is battery resistance.

8. An electronic battery tester comprising:

a positive connector configured to couple to a positive terminal of the battery;

a negative connector configured to couple to a negative terminal of the battery;

a voltage sensor configured to measure an open circuit voltage of the battery;

an input configured to receive a temperature of the battery; and

battery test circuitry configured to;

(a) measure a dynamic parameter of the battery using the first and second connectors;

(b) estimate a full charge dynamic parameter and a full charge open circuit voltage of the battery;

(c) estimate a load voltage of the battery as a function of the estimated charged battery dynamic parameter, the charged open circuit voltage of the battery, a load resistance value and the temperature of the battery;

(d) predict a full charge bounceback voltage; and

(e) utilize the full charge bounceback voltage and the load voltage to rate the strength of the battery.

9. The apparatus of claim 8 wherein the input is configured to receive the temperature of the battery from a user.

10. The apparatus of claim 8 wherein the input is configured to receive the temperature of the battery from a temperature sensor.

11. The apparatus of claim 8 wherein the battery test circuitry is configured to measure the dynamic parameter in step (a) by determining a response of the battery to an applied current pulse.

12. The apparatus of claim 8 wherein the measured battery dynamic parameter is battery conductance.

13. The apparatus of claim 8 wherein the measured battery dynamic parameter is battery resistance.

14. The apparatus of claim 8 wherein the positive connector is a first Kelvin connector and the negative connector is a second Kelvin connector.