1. Field of the Invention
The present invention relates to a method for manufacturing a battery wiring module.
2. Description of the Related Art
An in-vehicle battery pack which is connected to a power converter for driving a motor is mounted on a vehicle such as a hybrid vehicle or an electric vehicle. The battery pack is equipped with a battery module including a plurality of battery cells. In the battery module, the battery cells overlap one another so that one-side electrode terminals of the battery cells are arranged in a line and the other-side electrode terminals thereof are arranged in a line. In the battery pack, the electrode terminals of the adjacent battery cells are connected to each other by a connection member such as a busbar so that the plurality of battery cells is connected in series or in parallel. Then, there is a case in which an electric wire is connected to each of the connection members. For this reason, when the battery module is assembled, there is a need to connect the electrode terminals at a plurality of positions by the connection members and to route the electric wires connected to the connection members on the battery module. Hitherto, a busbar module obtained by insert-molding a plurality of connection members in insulating resin has been used.
Incidentally, when the plurality of battery cells is connected in series or in parallel, there is a possibility that the durability of the battery cell may be degraded when a battery characteristic such as a voltage across the battery cells is not uniform. Here, in order to stop a charging or discharging operation before abnormality occurs in the voltage across the battery cells in the in-vehicle battery pack, the above-described electric wire (the voltage detection line) for detecting the voltage of the battery cell is provided in each connection member (each busbar). However, the plurality of voltage detection lines in the busbar module is routed on the battery module in a bound state. For this reason, when the number of the voltage detection lines is large in such a busbar module, the bound voltage detection lines are thickened. Thus, there is a possibility that the voltage detection line is not easily bent or is increased in weight so that the wiring is not easily made.
Further, the busbar module of the related art employs a structure in which the front end of the coated voltage detection line is peeled, a round terminal is crimped to an exposed core wire, the round terminal is fitted to an electrode terminal of the battery cell, and the round terminal is fixed to a male screw portion of the electrode terminal along with a connection member by a nut. For this reason, there is a possibility that the busbar module may cause a voltage drop due to an increase in resistance of a contact surface between the connection member and the round terminal.
Here, in the battery pack of the related art, there is proposed a high-voltage detection module device (a busbar module) capable of easily wiring the battery cells with a simple structure and suppressing a voltage drop (for example, see Japanese Patent Application Laid-open No. 2010-114025). In the high-voltage detection module device of the battery pack, a plurality of busbars is disposed in an insulation frame assembled to a battery pack body so that a predetermined cathode terminal and a predetermined anode terminal are connected to each other in the battery cell, a flat cable is disposed in an area of the insulation frame other than the busbar arrangement area, and a conductor line having a base notched in a predetermined shape is welded to a predetermined busbar in the conductor lines of the flat cable.
Since the high-voltage detection module device includes the insulation frame, the plurality of busbars, and the flat cable, the structure is simplified. Further, since the high-voltage detection module device is formed by a step of arranging busbars in the insulation frame, a step of separating the conductor lines of the flat cable, and a step of welding the conductor lines to the busbars, the wiring operation is simplified.
However, in the high-voltage detection module device of Japanese Patent Application Laid-open No. 2010-114025, the insulation frame has a configuration in which a plurality of protrusion portions is provided in a lower surface of a flat rectangular plate-shaped portion with a predetermined gap therebetween and a plurality of openings is provided in the plate-shaped portion with a predetermined gap therebetween. That is, in the high-voltage detection module device, the predetermined gap between the plurality of protrusion portions fitted to a gap between the battery cells and the number of the protrusion portions need to be changed in response to the size of the battery cell as well as the predetermined gap between the plurality of openings opened at a gap between the cathode terminal and the anode terminal of the battery cell and the number of openings, and the insulation frame is dedicated in accordance with the type of the battery pack. For that reason, the high-voltage detection module device has a problem in which the versatility is low and the manufacturing cost is not easily decreased.