Battery packs suitable for use with battery powered appliances

• US 20030082439A1
• Filed: 10/28/2002
• Published: 05/01/2003
• Est. Priority Date: 11/01/2001
• Status: Active Grant

• Current Assignee: Makita Corporation
• Original Assignee: Makita Corporation
• Inventors: Sakakibara, Kazuyuki
• Granted Patent: US 7,238,443 B2
• Time in Patent Office: Days
• US Class Current: 429/120
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• CPC Class Codes: H01M 10/486 for measuring temperature
• 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 10/6554 Rods or plates
• CPC Class Codes: H01M 10/6563 with forced flow, e.g. by blowers
• CPC Class Codes: H01M 10/6566 Means within the gas flow to guide the flow around one or more cells, e.g. manifolds, baffles or other barriers H01M10/6565 takes precedence
• CPC Class Codes: H01M 50/107 having curved cross-section, e.g. round or elliptic H01M50/103, H01M50/109, H01M50/11 take precedence
• 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: H01M 50/24 adapted for protecting batteries from their environment, e.g. from corrosion thermal insulation H01M10/658
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

Cooling air intake port (52), cooling air exhaust port (55), and securing walls (86, 87), which contact and secure the side surfaces of one or more battery cells (72), may be defined within two battery pack housing halves (50, 80). When battery pack (99) is assembled, at least one cooling air passage (91, 92) is defined by the side surfaces of the battery cells, the interior surface of the battery pack housing, and the securing walls. The cooling air passage connects the cooling air intake port to the cooling air exhaust port. Further, the securing walls isolate or physically separate the cooling air passage from battery terminals (72a, 72b). By forcing cooling air through the cooling air passage, the battery cells can be effectively and efficiently cooled. In addition, if the battery terminals are isolated from the cooling air by the securing walls, the electrical contact areas of the battery cells are protected or shielded against outside moisture and foreign substances that may be introduced into the battery pack by the cooling air.

Claims

1. A battery pack, comprising:

a plurality of battery cells, each battery cell having a first battery terminal and a second battery terminal,

a housing substantially enclosing the plurality of battery cells,

a cooling air intake port and a cooling air exhaust port defined within the housing, and

at least one cooling air passage extending between the cooling air intake port and the cooling air exhaust port, the at least one cooling air passage being at least partially defined by at least one peripheral side surface of the battery cells and an inner surface of the housing, whereby cooling air directly communicates with the at least one peripheral side surface of the battery cells.

2. A battery pack as in claim 1, wherein the battery cells are positioned side-by-side such that at least one set of battery terminals is positioned within the same plane, and the at least one set of battery terminals is electrically connected to each other.

3. A battery pack as in claim 2, further comprising:

a first isolated space defined within the housing, wherein the first isolated space is physically isolated or shielded from the at least one cooling air passage and at least one of the first or second battery terminals is disposed within the first isolated space.

4. A battery pack as in claim 3, wherein the housing further comprises a first securing wall that further defines the at least one cooling air passage and separates the at least one cooling air passage from the first isolated space.

5. A battery pack as in claim 4, further comprising a second securing wall that further defines the at least one cooling air passage and separates the at least one cooling air passage from a second isolated space defined within the housing, wherein the first securing wall is substantially parallel to the second securing wall, the distance between the first and second securing walls at an upstream portion of the at least one cooling air passage is less than the distance between the first and second securing walls at a downstream portion of the at least one cooling air passage and a second set of battery terminals is disposed within the second isolated space.

6. A battery pack as in claim 5, further comprising at least one air direction changer disposed within the at least one cooling air passage, the at least one air direction changer directing or guiding cooling air flowing through the at least one cooling air passage toward at least one peripheral side surface of at least one downstream battery cell.

7. A battery pack as in claim 5, wherein the portion of the inner surface of the housing that defines at least one cooling air passage includes a surface that inclines towards the peripheral side surface of at least one downstream battery cell.

8. A battery pack as in claim 6, wherein the area of the peripheral side surfaces of upstream battery cells that directly communicate with the at least one cooling air passage is less than the area of the peripheral side surfaces of downstream battery cells that directly communicate with the at least one cooling air passage.

9. A battery pack as in claim 8, wherein the at least one cooling air passage comprises a first cooling air passage and a second cooling air passage, wherein the plurality of battery cells are disposed between the first and second cooling air passages.

10. A battery pack as in claim 9, wherein the first cooling air passage is shorter than the second cooling air passage and the air flow resistance of the first cooling air passage is greater than the second cooling air passage.

11. A battery pack as in claim 10, further comprising a temperature sensor disposed within a gap or space within the plurality of battery cells, which gap or space is isolated from the first and second cooling air passages, the temperature sensor being in communication with at least one battery cell.

12. A battery pack as in claim 11, wherein the battery cells are elongated and the first and second cooling air passages extend transversely to the longitudinal direction of the elongated battery cells.

13. A battery pack as in claim 12, further comprising insulating material disposed proximal to at least one battery cell disposed at an upstream portion of the second cooling air passage.

14. A battery pack as in claim 13, wherein the insulating material comprises a relatively rigid cover disposed on the peripheral side surface of the at least one battery cell.

15. A battery pack as in claim 14, further comprising an air gap defined between the peripheral side surface of the at least one battery cell and the relatively rigid cover, the air gap providing an insulating air layer between the at least one battery cell and the second cooling air passage.

16. A battery pack as in claim 15, further comprising heat sink material disposed at a downstream portion of the second cooling air passage, the heat sink material being positioned to conduct heat away from one or more downstream battery cells.

17. A battery pack as in claim 14, further comprising waterproof material at least partially disposed around at least one battery cell.

18. A battery pack as in claim 17, further comprising moisture absorbing material disposed between the at least one battery cell and the waterproof material.

19. A battery pack as in claim 1, further comprising insulating material disposed proximal to at least one battery cell disposed at an upstream portion of the at least one cooling air passage.

20. A battery pack as in claim 19, wherein the insulating material comprises a relatively rigid cover disposed on the peripheral side surface of the at least one battery cell.

21. A battery pack as in claim 20, further comprising an air gap defined between the peripheral side surface of the at least one battery cell and the relatively rigid cover, the air gap providing an insulating air layer between the at least one battery cell and the at least one cooling air passage.

22. A battery pack as in claim 20, further comprising heat sink material disposed at a downstream portion of the at least one cooling air passage, the heat sink material being positioned to conduct heat away from one or more downstream battery cells.

23. A battery pack as in claim 1, wherein the battery cells are elongated and the at least one cooling air passage extends transversely to the longitudinal direction of the elongated battery cells.

24. A battery pack as in claim 23, wherein the at least one cooling air passage comprises a first cooling air passage and a second cooling air passage, wherein the plurality of battery cells are disposed between the first and second cooling air passages.

25. A battery pack as in claim 24, wherein the first cooling air passage is shorter than the second cooling air passage and the air flow resistance of the first cooling air passage is greater than the second cooling air passage.

26. A battery pack as in claim 24, wherein the cross-section of the second cooling air passage that contacts the battery cells increases between the cooling air intake port and the cooling air exhaust port.

27. A battery pack as in claim 1, further comprising at least one air direction changer disposed within the at least one cooling air passage, the at least one air direction changer directing or guiding cooling air flowing through the at least one cooling air passage toward at least one peripheral side surface of at least one downstream battery cell.

28. A battery pack as in claim 27, wherein the portion of the inner surface of the housing that defines at least one cooling air passage includes a surface that inclines towards the peripheral side surface of at least one downstream battery cell.

29. A battery pack as in claim 27, wherein the area of the peripheral side surfaces of upstream battery cells that directly communicate with the at least one cooling air passage is less than the area of the peripheral side surfaces of downstream battery cells that directly communicate with the at least one cooling air passage.

30. A battery pack as in claim 1, wherein an insulating air layer is defined between at least one battery cell and the at least one cooling air passage, the insulating air layer insulating the battery cell from the cooling effects of the at least one cooling air passage.

31. A battery pack as in claim 30, wherein the at least one battery cell is disposed at an upstream portion of the at least one cooling air passage proximal to the cooling air intake port.