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Battery pack including an electric harness and method of manufacturing the same

Battery pack including an electric harness and method of manufacturing the same description/claims

This application claims priority to U.S. Provisional Patent Application No. 60/969,841, filed Sep. 4, 2007, the entire contents of which are hereby incorporated by reference.

The present invention generally relates to rechargeable battery packs for power tools. Rechargeable battery packs are available in numerous voltages (e.g., 12 v and 21 v) and are generally composed of multiple rechargeable battery cells connected either in series or in parallel. Some battery packs are manufactured using battery cells having a chemistry that can be damaged by overcharging (e.g., Lithium-ion). In battery packs containing multiple battery cells, some battery cells may have a different charge level than other battery cells in the battery pack. Recharging such a battery pack may result in overcharging a battery cell that has a higher charge level than other cells in the battery pack. Therefore, some battery packs, employing battery cells with chemistries sensitive to overcharging, monitor and charge each cell separately. Prior battery packs have included a controller to monitor and control charging of the battery cells. These battery packs generally include wires or straps connecting the individual battery cells to a circuit board that includes the controller. During manufacture of such battery packs, connecting the wires or straps between the battery cells and the circuit board is cumbersome and relatively expensive.

Embodiments of the invention relate to a system and method for connecting individual battery cells to a circuit board in a simple and inexpensive way.

In one embodiment, the invention provides a harness for a battery pack. The harness includes a frame and an electric coupler assembly. The electric coupler assembly is fixed to the frame, and includes a plurality of cell couplings, a plurality of circuit board couplings, and a plurality of links. The links are cut after the electric coupler assembly is fixed to the frame. The electric coupler assembly provides individual electrical connections to a plurality of battery cells via the plurality of cell couplings and the plurality of circuit board couplings, following cutting of the links.

In another embodiment, the invention provides a method of manufacturing a battery pack. The battery pack includes a top housing, a bottom housing, a frame, a cell pad, a plurality of battery cells, a circuit board, and an electric coupler assembly having a plurality of links, a plurality of cell couplings, and a plurality of circuit board couplings. The method includes the acts of molding the electric coupler assembly into the frame, severing the plurality of links, attaching the battery cells to the plurality of cell couplings after the links have been severed, and attaching the circuit board to the plurality of circuit board couplings. The circuit board is electrically connected to each battery cell individually.

In another embodiment, the invention provides a power tool battery pack, including a bottom housing, a cell pad positioned in the bottom housing, a plurality of battery cells supported by the cell pad, an electric harness coupled to the plurality of battery cells, a circuit board supported on the frame, and a top housing secured to the bottom housing. The top and bottom housings substantially enclose the cell pad, the plurality of battery cells, and the electric harness. The electric harness includes a frame and an electric coupler assembly fixed to the frame. The electric coupler assembly includes a plurality of cell couplings, a plurality of circuit board couplings, and a plurality of links. The links are cut after the electric coupler assembly is fixed to the frame. The electric coupler assembly provides individual electrical connections to the plurality of battery cells via the plurality of cell couplings and the plurality of circuit board couplings following cutting of the links.

In one embodiment, the invention provides a battery pack including a top housing, a bottom housing, a cell pad, a plurality of battery cells, a harness, and a circuit board. The harness individually electrically couples the plurality of battery cells to the circuit board.

In another embodiment, the invention provides a method of manufacturing a battery pack. The method includes the acts of molding an electric coupler assembly into a frame, the assembly having a plurality of internal and external couplings connected together by a plurality of links; cutting the plurality of links between internal and external couplings; connecting a plurality of battery cells to cell couplings of the internal and external couplings; connecting a plurality of circuit board couplings of the internal and external couplings to a circuit board; and positioning the electric coupler assembly, frame, and battery cells in a housing.

In another embodiment, the invention provides a harness for a battery pack. The harness includes a frame and an electric coupler assembly having a plurality of internal and external electric couplings. The internal and external electric couplings include cell couplings and circuit board couplings. The internal and external couplings are held in place during manufacturing by links which are cut after the electric coupler assembly is molded into the frame.

Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

FIG. 1 is an exploded view of a battery pack incorporating an embodiment of the invention.

FIG. 2 is a perspective view of an electric harness according to an embodiment of the invention.

FIG. 3 is a perspective view of an electric coupling assembly according to an embodiment of the invention.

FIG. 4 is a perspective view of the electric harness of FIG. 2 including a plurality of battery cells and a circuit board according to an embodiment of the invention.

• Provisional Patent
• Utility Patent

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