CN-122029675-A - Battery pack

Abstract

The invention aims to provide a battery pack which can prevent breakage of a voltage detection wire without using a new component. The battery pack includes a voltage detection wire having a1 st voltage detection wire 21a1 starting from an electrode joint terminal 25 for detecting the voltage of each cell, a2 nd voltage detection wire 21a2 connected to the 1 st voltage detection wire so as to branch midway of the 1 st voltage detection wire, and a connection terminal 27 tightly crimped to a connection portion of the 1 st voltage detection wire 21a1 and the 2 nd voltage detection wire 21a2, the voltage detection wire 21a including the connection terminal 27 being arranged in a wire wiring path 24c of the wire housing box 24, and a turn-back redundancy length portion 28 being formed in the 1 st voltage detection wire 21a1 between the electrode joint terminal 25 and the connection terminal 27.

Inventors

• XING HAO
• Pohu Youshu
• AIZAWA YASUKO

Assignees

• 日本汽车能源株式会社

Dates

Publication Date

20260512

Application Date

20250312

Priority Date

20240909

Claims (11)

1. 1. A battery pack, comprising: A plurality of stacked unit cells, and A state detection wire having a1 st state detection wire having a state detection terminal for detecting a state of each of the single cells and a2 nd state detection wire branched from a branching portion formed midway of the 1 st state detection wire, The plurality of state detection wires including the branch portion are arranged in a wire routing path of a wire housing box, and a folded-back redundancy length portion is formed in the 1 st state detection wire between the state detection terminal and the branch portion.
2. 2. The battery pack according to claim 1, wherein: the unit cell has a positive electrode terminal and a negative electrode terminal, and the unit cells are stacked in such a manner that the positive electrode terminal or the negative electrode terminal faces one side, The battery pack includes the state detection wire for detecting a state of the single cell, and a wire housing box having the wire wiring path for housing a plurality of the state detection wires, The state detection wire has: The 1 st state detection wire connected to the state detection terminal for detecting a state of one of the single cells and connected to a1 st output unit; The branch part formed in the middle of the 1 st state detecting wire, and The 2 nd state detecting wire branched from the branching portion and connected to the 2 nd output portion, The plurality of state detection wires include the state detection wire having the folded-back redundancy length portion formed between the state detection terminal and the branch portion of the 1 st state detection wire, The electric wire routing path extends along the 1 st direction of the cell stack, The 1 st state detection wire, the 2 nd state detection wire, the branching portion, and the folded-back redundancy length portion are housed in the wire routing path.
3. 3. The battery pack according to claim 1, wherein: The state detection wire is a voltage detection wire.
4. 4. A battery pack according to claim 3, wherein: The electric wire wiring path of the electric wire housing case is a housing space surrounded by an upper plate of the electric wire housing case and a pair of side plates connected to the upper plate, The 1 st voltage detecting wire, the 2 nd voltage detecting wire and the branching portion are housed in the housing space, The length (L) of the folded redundant length part is set longer than the length (W) of the pair of side plates which are opposite to each other.
5. 5. A battery pack, comprising: A plurality of stacked unit cells; A bus bar provided at each of the single cells; A wire storage box arranged along a stacking direction of the single cells; A wire routing path formed in the wire housing box, and A voltage detecting wire disposed in the wire wiring path and connected to an electrode bonding terminal soldered to the bus bar, The voltage detecting wire includes at least a 1 st voltage detecting wire starting from the electrode bonding terminal, a2 nd voltage detecting wire connected to the 1 st voltage detecting wire so as to branch midway of the 1 st voltage detecting wire, and a branching portion which is tightly press-bonded to a connecting portion of the 1 st voltage detecting wire and the 2 nd voltage detecting wire, The voltage detection wire including the branch portion is disposed in the wire routing path of the wire housing box, and a folded-back redundancy length portion is formed in the 1 st voltage detection wire between the electrode bonding terminal and the branch portion.
6. 6. The battery pack according to claim 5, wherein: The electric wire wiring path of the electric wire housing case is a housing space surrounded by an upper plate of the electric wire housing case and a pair of side plates connected to the upper plate, The 1 st voltage detecting wire, the 2 nd voltage detecting wire and the branching portion are housed in the housing space, The length of the folded redundant length portion is set longer than the length of the pair of side plates facing each other.
7. 7. The battery pack according to claim 2, wherein: The state detection wire is a voltage detection wire.
8. 8. The battery pack according to claim 2, wherein: The state detecting wire has a3 rd state detecting wire not provided with the branching portion, The electric wire routing path includes the folded-back redundancy length portion having a length shorter than the folded-back redundancy length portion of the 1 st state detection electric wire, or the 3 rd state detection electric wire not having the folded-back redundancy length portion.
9. 9. The battery pack according to claim 2, wherein: The single cell has a gas discharge valve that opens when the internal pressure of the cell becomes a prescribed value, The electric wire housing box has an opening portion facing the gas discharge valve along the 1 st direction, The battery pack includes a plurality of the electric wire routing paths formed along the 1 st direction and arranged on both sides of the opening.
10. 10. The battery pack according to claim 2, wherein: The electric wire wiring path is formed at a position farther from an end of the unit cell than the positive electrode terminal or the negative electrode terminal in a2 nd direction passing through the positive electrode terminal and the negative electrode terminal of the unit cell.
11. 11. A battery pack, comprising: A plurality of stacked unit cells, and A state detection wire having a1 st state detection wire, a2 nd state detection wire, the 1 st state detection wire starting from a state detection terminal for detecting a state of each of the single cells, the 2 nd state detection wire being connected to the 1 st state detection wire in a manner branching from halfway of the 1 st state detection wire, and a connection terminal being tightly crimped at a connection portion of the 1 st state detection wire and the 2 nd state detection wire, The state detection wire including the connection terminal is disposed in a wire routing path of a wire housing box, and a turn-back redundancy length portion is formed in the 1 st state detection wire between the state detection terminal and the connection terminal.

Description

Battery pack Technical Field The present invention relates to a battery pack configured by connecting a plurality of unit cells, and more particularly, to a battery pack including a state detection wire connected to a detection unit that detects a state (e.g., a state such as a voltage) of each unit cell. Background For example, an electrolyte battery including a positive electrode layer and a negative electrode layer capable of occluding and releasing lithium ions has been widely used in various fields such as electric vehicles, hybrid vehicles, and electric power storage as a battery having a high energy density. Further, an electrolyte battery using a liquid electrolyte or an electrolyte battery using a solid electrolyte is known. In a secondary battery using an electrolyte battery, a battery pack is constituted by connecting a plurality of single cells (electrolyte batteries). The battery pack can obtain a large electric power by electrically connecting the unit cells to each other using an electrode member (hereinafter referred to as a bus bar) made of a conductive metal such as aluminum, copper, or iron. Further, the battery pack includes a pair of external terminals enabling electric power transmission and reception, and the bus bar and the pair of external terminals are constituted by an insulating member mainly composed of engineering plastic that insulates adjacent bus bars from each other and insulates a strong electric portion including the external terminals. Here, the battery pack includes a voltage detection wire connected to the bus bar for detecting the voltage of each cell, and voltage information of the cell is acquired from the voltage detection wire and sent to the control unit for charge/discharge control of the battery pack by the control unit. In particular, a battery pack mounted in an automobile or the like is used at a wide range of ambient temperatures including a low-temperature state to a high-temperature state. Further, since the input/output characteristics and lifetime characteristics of the battery have temperature dependency, voltage information is required to appropriately control charge/discharge of the battery pack. As such a battery pack including a voltage detection wire, for example, a technique described in japanese patent application laid-open No. 2019-139925 (patent document 1) is known. Patent document 1 discloses a battery pack including a plurality of battery cells, a case accommodating the battery cells, a plurality of voltage detection wires each having one end electrically connected to an electrode bonding terminal of each of the battery cells, a first connector configured to collect the other ends of the voltage detection wires, a second connector configured to be inserted into the first connector, and a substrate on which the second connector is mounted, wherein the case is opposed to the substrate, and the first connector is inserted into the second connector in a direction along a surface of the substrate opposed to the case. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2019-139925 Disclosure of Invention Technical problem to be solved by the invention However, in such a battery pack including a plurality of voltage detection wires, there is a case where a wiring structure is employed that makes the copper wire constituting the voltage detection wire branch from the middle to another copper wire when seen from the electrode-joining terminal direction of the bus bar. Therefore, it is preferable that the tension load or the repetitive load is not applied to the voltage detection wire that is directed to the electrode-joining terminal of the bus bar, and the branching portion is excessively moved or repeatedly moved, so that unnecessary force is applied to the branching portion. In the embodiments described below, the voltage detection wire is the object, but there are cases where similar technical problems are present in detection wires other than the voltage detection wire, for example, in temperature detection wires for detecting the temperature of the single cells. Therefore, the voltage detection wire and the temperature detection wire may be generalized, and may be referred to as a "state detection wire". The invention provides a battery pack having highly reliable state detection wires. Means for solving the technical problems The invention is characterized by comprising a plurality of single cells stacked, and a state detection wire, wherein the state detection wire is provided with a 1 st state detection wire and a 2 nd state detection wire, the 1 st state detection wire is provided with a state detection terminal used for detecting the state of each single cell, the 2 nd state detection wire is branched from a branching part formed midway of the 1 st state detection wire, the plurality of state detection wires comprising the branching part are arranged in a wire wiring path of a wire accommodat