BATTERY PACK WITH HEAT SINK

• US 20140272517A1
• Filed: 03/12/2014
• Published: 09/18/2014
• Est. Priority Date: 03/12/2013
• Status: Active Grant

• Current Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Original Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Inventors: Glasgow, Kevin L., Verbrugge, Brandon L.
• Granted Patent: US 9,912,020 B2
• Time in Patent Office: Days
• US Class Current: 429/120
• CPC Class Codes: B25F 5/008 Cooling means
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/6235 Power tools
• CPC Class Codes: H01M 10/643 Cylindrical cells
• CPC Class Codes: H01M 10/6551 Surfaces specially adapted for heat dissipation or radiation, e.g. fins or coatings
• CPC Class Codes: H01M 10/6554 Rods or plates
• CPC Class Codes: H01M 10/6555 arranged between the cells
• CPC Class Codes: H01M 2220/30 Batteries in portable systems, e.g. mobile phone, laptop
• CPC Class Codes: H01M 50/213 adapted for cells having curved cross-section, e.g. round or elliptic H01M50/209, H01M50/216 take precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery pack including a housing including an inner cavity and an interface for receiving a power tool. The interface includes electrical terminals operable to interface with the power tool. Battery cells are positioned within the cavity and are electrically coupled to the electrical terminals. The battery pack also includes at least a portion of the housing that is configured as a heat sink to passively dissipate heat generated in the cavity to an external environment of the battery pack.

Claims

1. A battery pack comprising:

a housing including a plurality of walls, an inner cavity and an interface for receiving a power tool, the interface including electrical terminals operable to interface with the power tool;

battery cells positioned within the inner cavity and electrically coupled to the electrical terminals; and

a heat sink forming at least a portion of one of the plurality of walls of the housing to at least partially define the inner cavity;

wherein the heat sink includes a first surface exposed to the inner cavity and second surface exposed to an external environment of the battery pack.

2. The battery pack of claim 1, wherein the heat sink is constructed from a thermally conductive material and at least one other of the plurality of walls is constructed from a second material that has a thermal conductivity that is less than the thermally conductive material.

3. The battery pack of claim 1, wherein at least a portion of the heat sink extends through an aperture in the at least one wall of the housing to establish a thermal path from the inner cavity to the external environment.

4. The battery pack of claim 1, further comprising an electrically isolating layer between the battery cells and the heat sink.

5. The battery pack of claim 1, wherein the heat sink includes a first surface that includes a plurality of grooves, each of the grooves shaped to receive one of the battery cells.

6. The battery pack of claim 5, wherein the heat sink includes a second surface that is opposite the first surface, the second surface including a plurality of projections and a plurality of channels.

7. The battery pack of claim 1, further comprising an internal frame positioned within the cavity and configured to secure the battery cells relative to the housing.

8. The battery pack of claim 1, further comprising a printed circuit board positioned within the cavity.

9. A battery pack comprising:

a housing including an interface for receiving a power tool, a base portion of the housing, and a plurality of walls that couple the interface to the base portion, wherein the interface, base portion, and the plurality of walls define an inner cavity, the interface including electrical terminals operable to interface with the power tool;

battery cells positioned within the inner cavity and electrically coupled to the electrical terminals; and

a heat sink forming at least a portion of the housing;

wherein the heat sink includes a first surface that is opposite a second surface, the first surface in thermal communication with the battery cells, and a second surface including a plurality of heat transfer elements exposed to an external environment of the battery pack.

10. The battery pack of claim 9, wherein the heat sink is constructed from a metal material.

11. The battery pack of claim 9, wherein the first surface includes a plurality of grooves, each of the grooves sized and shaped to receive one of the battery cells.

12. The battery pack of claim 9, further comprising an electrically isolating layer between the battery cells and the first surface of the heat sink.

13. The battery pack of claim 9, wherein the heat transfer elements include a plurality of projections with a channel defined between adjacent projections.

14. The battery pack of claim 9, wherein the heat sink forms the base portion.

15. The battery pack of claim 14, further comprising an overmold covering the base portion, the overmold including an aperture, the heat transfer elements at least partially extending through the aperture.

16. The battery pack of claim 9, further comprising an internal frame positioned within the cavity and configured to secure the battery cells relative to the housing.

17. A battery pack comprising:

a housing including a plurality of walls, an inner cavity, and an interface for receiving a power tool, the interface including electrical terminals operable to interface with the power tool;

battery cells positioned within the inner cavity and electrically coupled to the electrical terminals; and

a metal heat sink fixed in one of the plurality of walls, wherein the metal heat sink is configured to passively dissipate heat generated in the inner cavity to an external environment of the battery pack.

18. The battery pack of claim 17, wherein the metal heat sink includes a first surface that is opposite a second surface, the first surface including a plurality of grooves, each of the grooves sized and shaped to receive one of the battery cells, and the second surface including a plurality of projections and a plurality of channels.

19. The battery pack of claim 17, wherein the metal heat sink includes an outer surface and fins projecting away from the outer surface.

20. The battery pack of claim 19, further comprising an overmold covering at least a portion of the housing, the overmold including an aperture, and the fins at least partially extending through the aperture.