Battery packs suitable for use with battery powered appliances

• US 7,879,483 B2
• Filed: 07/07/2009
• Issued: 02/01/2011
• Est. Priority Date: 11/01/2001
• Status: Expired due to Term

• Current Assignee: Makita Corporation
• Original Assignee: Makita Corporation
• Inventors: Sakakibara, Kazuyuki
• Primary Examiner(s): Maples; John S
• Application Number:
  US12/498,736
• Publication Number:
  US 20090269655A1
• Time in Patent Office: 574 Days
• Field of Search: None
• 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,

a housing substantially enclosing the plurality of battery cells,

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

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 peripheral side surfaces of the battery cells and an inner surface of the housing, wherein the plurality of battery cells includes upstream battery cells located at an upstream portion of the at least one cooling air passage and downstream battery cells located at a downstream portion of the at least one cooling air passage; and

at least one slope formed on a portion of the inner surface of the housing that defines the downstream portion of the at least one cooling air passage, each of the at least one slope locally-projecting from the inner surface of the housing towards a single one of the downstream battery cells and changing direction of cooling air flowing through the at least one cooling air passage towards the peripheral side surface of the single one of the downstream battery cells;

wherein the at least one slope comprises at least two slopes, each of the at least two slopes projecting towards a same one of the downstream battery cells located at a furthest downstream position.

2. A battery pack as in claim 1, further comprising a heat insulating member disposed at the upstream portion of the at least one cooling air passage, wherein the heat insulating member at least partially shields the surface of at least one upstream battery cell from cooling air flowing through the at least one cooling air passage.

3. A battery pack as in claim 1, further comprising a heat sink member disposed at the downstream portion of the at least one cooling air passage, wherein the heat sink member conducts heat away from at least one downstream battery cell.

4. A battery pack as in claim 1, wherein the at least one cooling air passage comprises a first cooling air passage and a second cooling air passage, wherein the plurality of the battery cells are disposed between the first and second cooling air passages.

5. A battery pack as in claim 1, 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.

6. A battery pack as in claim 1, 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.

7. A battery pack as in claim 1, wherein the plurality of battery cells comprises elongated battery cells positioned side-by-side, and the at least one cooling air passage extends transversely to the longitudinal direction of the elongated battery cells.

8. A battery pack as in claim 1, wherein the at least one slope comprises at least three slopes, one of the at least three slopes projecting towards a first one of the downstream battery cells and two of the at least three slopes projecting towards a second one of the downstream battery cells, wherein the second one of the downstream battery cells is located at a downstream side of the first one of the downstream battery cells.