Battery cooling system

• US 20030027037A1
• Filed: 08/20/2002
• Published: 02/06/2003
• Est. Priority Date: 03/05/1998
• Status: Active Grant

• Current Assignee: Daniele C. Brotto, Fred S. Watts, Janet M. Embrey, John R. Cochran, Lee W. Ramstrom, Paul S. White, Robert Bradus, Robert G. Moores Jr, Rouse R. Bailey Jr
• Original Assignee: Daniele C. Brotto, Fred S. Watts, Janet M. Embrey, John R. Cochran, Lee W. Ramstrom, Paul S. White, Robert Bradus, Robert G. Moores Jr, Rouse R. Bailey Jr
• Inventors: Brotto, Daniele C., Bradus, Robert, White, Paul S., Watts, Fred S., Cochran, John R., Embrey, Janet M., Bailey, Rouse R. Jr., Ramstrom, Lee W., Moores, Robert G. Jr.
• Granted Patent: US 6,949,309 B2
• Time in Patent Office: Days
• US Class Current: 429/82
• CPC Class Codes: B25F 5/008 Cooling means
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/615 Heating or keeping warm
• CPC Class Codes: H01M 10/617 for achieving uniformity or desired distribution of temperature
• CPC Class Codes: H01M 10/623 Portable devices, e.g. mobile telephones, cameras or pacemakers
• CPC Class Codes: H01M 10/6235 Power tools
• CPC Class Codes: H01M 10/63 Control systems charging or discharging in response to temperature H01M10/44 , H01M10/443; measurement of temperature H01M10/48 , H01M10/486
• CPC Class Codes: H01M 10/643 Cylindrical cells
• CPC Class Codes: H01M 10/652 characterised by gradients for achieving a desired temperature gradient H01M10/617
• CPC Class Codes: H01M 10/653 characterised by electrically insulating or thermally conductive materials
• 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 10/6556 Solid parts with flow channel passages or pipes for heat exchange closed pipes H01M10/6552
• CPC Class Codes: H01M 10/6557 arranged between the cells
• 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 10/6572 : Peltier elements or thermoelectric devices
• CPC Class Codes: H01M 10/66 : Heat-exchange relationships between the cells and other systems, e.g. central heating systems or fuel cells
• CPC Class Codes: H01M 10/667 : the system being an electronic component, e.g. a CPU, an inverter or a capacitor
• CPC Class Codes: H01M 50/204 : Racks, modules or packs for multiple batteries or multiple cells
• 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 50/247 : specially adapted for portable devices, e.g. mobile phones, computers, hand tools or pacemakers
• CPC Class Codes: H01M 50/30 : Arrangements for facilitating escape of gases
• CPC Class Codes: H02J 7/0042 : characterised by the mechanical construction
• CPC Class Codes: H02J 7/0044 : specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence
• 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
• CPC Class Codes: Y10T 29/49108 : Electric battery cell making

Abstract

A cordless power tool has a housing which includes a mechanism to couple with a removable battery pack. The battery pack includes one or more battery cells as well as a vent system in the battery pack housing which enables fluid to move through the housing. A mechanism is associated with the battery pack to dissipate heat from the battery pack.

Claims

1. A battery pack to be inserted in an electrical appliance by movement along a first direction comprising:

a housing having top, bottom and side walls, a terminal tower disposed on the top wall, an air inlet disposed on at least one of the terminal tower and the top wall, and an air outlet for allowing air to exit from the housing;

a plenum disposed within the housing and connected to the air inlet, the plenum having at least one hole for allowing air to move therethrough;

a first cell disposed within the housing and against the plenum;

a filter disposed within the housing and near the air outlet; and

an insulation plate disposed between the filter and the first cell.

2. The battery pack of claim 1, wherein the air outlet is disposed on one of the side walls.

3. The battery pack of claim 1, wherein the first cell has a longitudinal axis substantially parallel to the first direction.

4. The battery pack of claim 1, wherein air entering the housing through the air inlet moves along a second direction substantially perpendicular to the first direction.

5. The battery pack of claim 1, wherein air exiting housing through the air outlet moves along a second direction substantially parallel to the first direction.

6. The battery pack of claim 1, wherein the plenum comprises at least one rib for holding the first cell in place.

7. The battery pack of claim 1, wherein the housing comprises at least one rib for holding the first cell in place.

8. The battery pack of claim 1, further comprising a temperature indicating device.

9. The battery pack of claim 8, wherein the temperature indicating device is exposed to the air entering and exiting the housing.

11. The battery pack of claim 1, further comprising a second cell disposed within the terminal tower.

12. The battery pack of claim 1, further comprising a set of cells surrounding the first cell.

13. The battery pack of claim 12, wherein the plenum has first and second sets of holes, where the first set of holes is closer to the first cell and the second set of holes is farther from the first cell and closer to the set of cells surrounding the first cell.

14. The battery pack of claim 13, wherein diameter of the holes in the first set is larger than diameter of the holes in the second set.

15. The battery pack of claim 1, having a movable door disposed on the housing, the door being movable between a first position closing the air inlet and a second position opening the air inlet.

16. The battery pack of claim 15, wherein the door slides between the first and second positions.

17. The battery pack of claim 15, wherein the door moves between the first and second position when the battery pack is disposed on a charger.

18. The battery pack of claim 15, further comprising a spring biasing the door towards the first position.

10. The battery pack of 8, wherein the temperature indicating device is one of the group consisting of thermistors, thermostats, capacitors and resistors.

19. A method for manufacturing a battery pack, comprising:

providing a first plurality of cells;

assembling the first plurality of cells into a first cluster;

disposing the first cluster on a plenum;

disposing a first insulation plate on the first cluster;

disposing a first filter on the first insulation plate; and

disposing the first cluster and plenum within a housing.

20. The method of claim 19, further comprising disposing a temperature indicating device within the housing.

21. The method of claim 19, further comprising providing a second plurality of cells, assembling the second plurality of cells into a second cluster and disposing the second cluster on the plenum.

22. The method of claim 21, wherein the second cluster is disposed within the housing with the first cluster and plenum.

23. The method of claim 21, further comprising:

disposing a second insulation plate on the second cluster; and

disposing a second filter on the second insulation plate.

24. The method of claim 19, wherein assembling the first plurality of cells comprises connecting the first plurality of cells.

25. The method of claim 19, wherein assembling the first plurality of cells comprises taping the first plurality of cells.

26. A charger for charging a battery pack, the battery pack comprising a housing having top, bottom and side walls, a terminal tower disposed on the top wall, an air inlet disposed on at least one of the terminal tower and the top wall, and an air outlet for allowing air to exit from the housing, a plurality of cells disposed in the housing, the charger comprising:

a charger housing for supporting the battery pack, the charger housing having a first duct opposite of the air inlet of the battery pack;

charging circuitry provided within the charger housing; and

a fan disposed within the charger housing for blowing air through the first duct and into the battery pack via the air inlet, and for blowing air through a second duct directing cooling air to the charging circuitry.

27. The charger of claim 26, wherein the first duct and the air inlet of the battery pack are axially aligned.

28. The charger of claim 26, wherein the first duct and the air inlet of the battery pack are axially misaligned.

29. The charger of claim 26, further comprising a chamber disposed between the first duct and the air inlet of the battery pack.

30. A charger for charging a battery pack, the battery pack comprising a housing having top, bottom and side walls, a terminal tower disposed on the top wall, an air inlet disposed on at least one of the terminal tower and the top wall, and an air outlet for allowing air to exit from the housing, a plurality of cells disposed in the housing, the charger comprising:

a charger housing for supporting the battery pack, the charger housing having a first duct opposite of the air inlet of the battery pack and vents disposed near the air exiting from the battery pack housing;

a fan disposed within the charger housing for blowing air through the first duct and into the battery pack via the air inlet;

wherein air exiting from the battery pack housing creates a low pressure region near the vents.

31. The charger of claim 30, wherein the first duct and the air inlet of the battery pack are axially aligned.

32. The charger of claim 30, wherein the first duct and the air inlet of the battery pack are axially misaligned.

33. The charger of claim 30, further comprising a chamber disposed between the first duct and the air inlet of the battery pack.

34. A battery pack comprising:

a housing having an air inlet for allowing air to enter the housing and an air outlet for allowing air to exit the housing;

a first cell disposed within the housing;

a temperature indicating device disposed within the housing for providing temperature information, the temperature indicating device being exposed to air moving through the housing.

35. The battery pack of claim 34, wherein the temperature indicating device is one of the group consisting of thermistors, thermostats, capacitors and resistors.

36. A method for controlling a charger for charging a battery, wherein the charger comprises a fan for cooling the battery, the method comprising:

providing power to the fan so that it rotates at a first speed prior to battery insertion.

37. The method of claim 36, wherein the power is provided when the charger is connected to a power supply source.

38. The method of claim 36, wherein the power is provided when the charger is turned on.

39. The method of claim 36, wherein the power is provided when a button disposed on the charger is activated.

40. The method of claim 36, wherein the power is provided for a predetermined period of time.

41. The method of claim 36, further comprising providing power to the fan so that it rotates at a second speed lower than the first speed.

42. The method of claim 41, wherein the second speed is equal to zero revolutions per minute.

43. A method for controlling a charger for charging a battery, wherein the charger comprises a fan for cooling the battery, the method comprising:

determining battery temperature;

providing power to the fan so that it rotates at a first speed if the battery temperature is above a predetermined temperature; and

providing power to the fan so that it rotates at a second speed lower than the first speed if the battery temperature is equal to or below a predetermined temperature.

44. The method of claim 43, wherein the predetermined temperature is about 20°

C.

45. The method of claim 43, wherein the second speed is equal to zero revolutions per minute.

46. A method for controlling a charger for charging a battery, wherein the charger comprises a fan for cooling the battery, the method comprising:

providing power to the fan so that it rotates at a first speed;

providing power to the fan so that it rotates at a second speed lower than the first speed

determining battery temperature; and

providing power to the fan so that it rotates at a third speed.

47. The method of claim 46, wherein the second speed is equal to zero revolutions per minute.

48. The method of claim 46, wherein the third speed is selected so as to maintain battery temperature at a predetermined temperature.

49. The method of claim 48, wherein the predetermined temperature is about 30°

C.

50. The method of claim 46, wherein the third speed is about equal to the first speed.

51. A method for cooling a battery disposed on a charger, the method comprising:

providing a fan in the charger;

providing an air inlet in the battery for allowing air to enter the battery;

providing an air outlet in the battery for allowing air to exit the battery;

providing power to the fan to force air to enter the battery through the air inlet, to exit the battery through the air outlet and to enter the charger, in that order.