Battery pack

• US 6,232,749 B1
• Filed: 12/10/1999
• Issued: 05/15/2001
• Est. Priority Date: 12/10/1999
• Status: Expired due to Term

• Current Assignee: Duracell U.S. Operations, Inc. (Berkshire Hathaway Incorporated)
• Original Assignee: Gillette Company (The Procter & Gamble Company)
• Inventors: Hull, Matthew P., Hewes, Jeffrey, Yoppolo, Robert
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/459,196
• Time in Patent Office: 522 Days
• Field of Search: 320/135, 320/136, 320/107, 320/112, 307/66, 307/150, 307/151
• US Class Current: 320/135
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A battery pack is described. The battery pack includes a DC to DC converter and a group of at least two primary cells. The DC-DC converter is operatively coupled to the group of primary cells. The group of primary cells have an initial voltage that is higher than a rated voltage for the battery pack. The DC-DC converter converts the voltage to a regulated nominal voltage that is lower that the rated voltage of the group of primary cells. By regulating the battery voltage down to a constant voltage, the cells can discharge down to a minimum voltage level per cell enabling additional energy transfer from the group of cells.

Claims

1. A battery pack having an nominal output voltage rating, comprises:

a group of primary cells, the group of cells having a nominal voltage rating that is in excess of the nominal voltage rating of the battery pack;

a DC to DC converter, the DC to DC converter configured to discharge the group of cells down to a voltage level of about the terminal voltage of cell, before the DC-DC converter cuts out, enabling a maximum amount of energy transfer from the cells, with the group of primary cells coupled to discharge through the DC to DC converter.

2. The battery pack of claim 1 wherein the group comprises:

at least two cells, and wherein the DC-DC converter is a step-down converter.

3. The battery pack of claim 2 wherein the group of primary cells comprise:

a plurality of cells coupled in series.

4. The battery pack of claim 1 wherein the DC-DC converter comprises:

a controller device for current switching and an externally coupled switching transistor, arranged to switch high levels of current from the battery in accordance with a load placed on the battery.

5. The battery pack of claim 1 wherein the DC-DC converter has an input coupled to one terminal of the group of primary cells and an output that forms one of the terminals of the battery pack.

6. The battery pack of claim 1 wherein the group of at least one primary cell is replaceable.

7. The battery pack of claim 1 wherein the group of at least one primary cell is not replaceable.

8. The battery pack of claim 1 further comprising:

a case that houses the DC to DC converter and group of primary cells.

9. The battery pack of claim 1

wherein the DC-DC converter is a step-up converter.

10. The battery pack of claim 2 wherein the group of primary cells comprise a plurality of cells coupled in parallel.

11. A battery pack, comprises:

a DC to DC converter;

a group of at least two primary cells, with the DC-DC converter operatively coupled to the group of primary cells and with the group of primary cells having an initial voltage that is higher than a rated voltage for the battery pack;

case housing the DC-DC converter and the group of primary cells; and

a pair of external battery terminals coupled to the DC-DC converter and supported on the case.

12. The battery pack of claim 11 wherein the DC-DC converter converts the voltage of the group of cells to a regulated nominal voltage that is lower that the rated voltage of the group of primary cells.

13. The battery pack of claim 11 wherein the DC-DC converter prevents excessive voltage from appearing at terminals of the battery pack.

14. The battery pack of claim 11 wherein by regulating the battery voltage down to a constant voltage, the cells can be discharged down to a minimum voltage level per cell.

15. The battery pack of claim 14 wherein at the minimum voltage level per cell the DC-DC converter will cut out.

16. The battery pack of claim 15 wherein discharging down to a minimum voltage level per cell enables additional energy transfer from the group of cells.

17. The battery pack of claim 16 wherein the group of primary cells include a plus terminal and a minus terminal with the plus terminal of the group of primary cells connected to an input side of the DC to DC converter.