TEMPERATURE SENSING SYSTEM FOR RECHARGEABLE BATTERIES

• US 3,736,489 A
• Filed: 05/21/1971
• Issued: 05/29/1973
• Est. Priority Date: 05/21/1971
• Status: Expired due to Term

• Current Assignee: Gates Energy Products, Inc. (Schneider Electric SE)
• Original Assignee: Ferdinand H. Mullersman
• Inventors: Mullersman, Ferdinand H.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/145,724
• Time in Patent Office: 739 Days
• Field of Search: 320/31,35,39,40
• US Class Current: 320/152
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An improved temperature sensing system for rechargeable batteries is provided which utilizes the voltage developed across one or a group of series connected diodes such as, for example, silicon diodes, at a preselected constant current to indicate the temperature of the battery and to accordingly adjust the level of battery voltage at which charge control action should be accomplished. When constant current charging is used, the proportionality between the voltage across the diodes and the desired voltage at which a high charge rate is modified can be made constant over a large temperature range by selecting the proper level of constant current to be passed through the diodes.

Claims

1. A battery charging system for a rechargeable battery having temperature compensated voltage sensing means wherein a charger recharges the battery at a high rate of charge to a predetermined charge level indicated by an increase in battery voltage to a pre-determined level which varies with the temperature of the battery, said temperature compensated voltage sensing means comprising:

A. Diode means in thermal communication with said battery, having a predetermined linear temperature co-efficient of voltage substantially matching the temperature co-efficient of voltage of said battery which comprises the change in voltage per degree change in temperature at said predetermined charge level during charging over a temperature range of from about 25* to +75* C;

B. Constant current means to pass a constant current through said diode means to provide a temperature-variable voltage over said temperature range which will be in a substantially constant direct proportion to said temperature-variable battery voltage at said predetermined charge level relatively independent of the temperature of the battery;

C. Voltage monitoring means to measure the voltage across said diode means and across said battery; and

D. Charge control means including a switch to turn off said high rate of charge in response to a signal voltage from said sensing means when the battery voltage reaches a predetermined proportion of said voltage across said diodes.

2. The system of claim 1 wherein said diode means comprises a plurality of series-connected diodes.

3. The system of claim 2 wherein said battery comprises a casing having at least two parallel rows of cells therein with a central portion between the rows and said sensing means are mounted in said central portion spaced from said casing and in thermal communication with at least two cells in each row.

4. A rechargeable battery comprising a casing having a plurality of cells arranged in two, parallel rows therein;

and having temperature sensing means therein comprising a channel shaped member placed between said rows, said member having a central portion and fin portions, one of said fin portions thermally contacting a plurality of cells in one row and another fin portion thermally contacting a plurality of cells in the other row, said central portion having series-connected diodes therein having a predetermined linear temperature coefficient substantially matching the temperature coefficient of voltage of said cells and thereby providing, in response to an impressed constant current, a signal voltage which will remain at a substantially constant proportion to the cut-off voltage of said cells over a temperature range of from about -25*C to about +75*C.

5. The battery of claim 4 wherein said diodes in sAid central portion are embedded in a potting compound.

6. The battery of claim 5 wherein an external connection is provided on said casing in electrical communication with said sensing means.