Cell bypass circuit

• US 4,935,315 A
• Filed: 12/05/1988
• Issued: 06/19/1990
• Est. Priority Date: 12/05/1988
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Herrin, Jerry
• Primary Examiner(s): Kalafut, Stephen J.
• Application Number:
  US07/279,759
• Time in Patent Office: 561 Days
• Field of Search: 429/50, 429/61, 429/90, 429/92, 429/93, 337/15, 337/20
• US Class Current: 429/50
• CPC Class Codes: H01M 10/42 Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells H01M10/60 takes precedence
• CPC Class Codes: H01M 2200/10 Temperature sensitive devices
• CPC Class Codes: H01M 50/583 in response to current, e.g. fuses
• CPC Class Codes: H02H 7/18 for batteries; for accumulators
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A cell bypass circuit is disclosed which includes a diode 32 connected electrically in parallel with a cell 20 of a battery 12. A thermal switch 34 is mounted in thermal contact with a diode 32. A relay 38 including a coil 36 and a contact 40 is provided. The coil 36 is connected to the thermal switch 34 so as to be activated by the activation thereof. The contact 40 of the relay 38 is connected in parallel with the cell 20 so that the activation of the diode 32 causes thermal energy to radiate therefrom activating the thermal switch 34. The activation of the thermal switch 34 causes the activation of the relay 38 which in turn places an electrical short across the defective cell 20 via the contacts 40 thereof.

Claims

1. A cell bypass circuit including:

a diode connected electrically in parallel with said cell;

a thermal switch mounted in thermal contact with said diode;

a relay including a coil and a contact, said coil being connected to said thermal switch so as to be activated by the activation thereof, and said contact being connected in parallel with said cell;

whereby the activation of said diode causes thermal energy to radiate therefrom activating said thermal switch thereby and the activation of said thermal switch causes the activation of said relay which in turn places an electrical short via said contacts across said cell.

2. The cell bypass circuit of claim 1 including a fuse between one terminal of said contact and one terminal of said cell.

3. A cell bypass circuit including:

a photodiode connected electrically in parallel with said cell;

a photosensitive means for detecting light emitted by said photodiode;

a relay including a coil and a contact, said coil being connected to said photosensitive means so as to be activated by the activation thereof, and said contact being connected in parallel with said cell;

whereby the activation of said diode causes optical energy to radiate therefrom activating said photosensitive means thereby and the activation of said photosensitive means causes the activation of said relay which in turn places an electrical short via said contacts across said cell.

4. The cell bypass circuit of claim 3 including a fuse between one terminal of said contact and one terminal of said cell.

5. A method of bypassing a defective cell of a battery including the steps of:

(a) monitoring the current flow through said cell;

(b) activating diode means when the current flow through the cell drops below a predetermined threshold;

(c) radiating energy from said diode means on the activation thereof;

(d) sensing the radiation from said diode means;

(e) activating a relay based on the radiation sensed from said diode means; and

(f) shorting said defective cell based on the activation of said relay.

6. A method of automatically bypassing a defective cell of a battery including the steps of:

(a) monitoring the current flow through said cell;

(b) activating diode means when the current flow through the cell drops below a predetermined threshold;

(c) sensing the radiation from said diode means on the activation thereof; and

(d) electrically bypassing said defective cell based on the receipt of radiation from said diode means.