Battery pack

Abstract

The purpose of the present invention is to provide a battery pack capable of preventing disconnection of a voltage detection wire without using a new component or the like. The battery pack is provided with a voltage detection wire having: a first voltage detection wire 21a1 starting from an electrode bonding terminal 25 for detecting the voltage of each single cell; a second voltage detection wire 21a2 connected to the first voltage detection wire so as to branch midway of the first voltage detection wire; and a connection terminal 27 that is fastened and crimped to a connection portion between the first voltage detection wire 21a1 and the second voltage detection wire 21a2, a voltage detection wire 21a including the connection terminal 27 is disposed in a wire routing path 24c of the wire storage box 24, and a fold-back redundant length portion 28 is formed in the first voltage detection wire 21a1 between the electrode bonding terminal 25 and the connection terminal 27.

Description

Technical Field

[0001] The present invention relates to a battery pack consisting of multiple individual cells connected together, and more particularly to a battery pack including a state detection wire connected to a detection unit for detecting the state (e.g., voltage state) of each individual cell. Background Technology

[0002] For example, electrolyte batteries, which include positive and negative electrode layers capable of absorbing / releasing lithium ions, are widely used in various fields such as electric vehicles, hybrid vehicles, and energy storage as high-energy-density batteries. Furthermore, electrolyte batteries are known to use either liquid electrolytes or solid electrolytes.

[0003] In secondary batteries using electrolyte batteries, a battery pack is formed by connecting multiple individual cells (electrolyte batteries). This battery pack can obtain a large electrical power by electrically connecting the individual cells to each other using electrode components (hereinafter referred to as bus bars) made of conductive metals such as aluminum, copper, and iron.

[0004] In addition, the battery pack includes a pair of external terminals that enable power transfer. The bus and the pair of external terminals are made of insulating components, mainly of engineering plastics, that insulate adjacent busbars from each other and from the high-voltage portion containing the external terminals.

[0005] Here, the battery pack, in order to detect the voltage of each individual cell, includes voltage detection wires connected to the busbar. The voltage information of each cell is obtained from the voltage detection wires and sent to the control unit for charge and discharge control of the battery pack. Battery packs, especially those used in automobiles, are used in a wide range of ambient temperatures, from low to high. Furthermore, the input / output characteristics and lifespan characteristics of a battery are temperature-dependent; therefore, voltage information is required for proper control of the battery pack's charge and discharge.

[0006] Regarding battery packs including voltage detection wires, for example, the technology described in Japanese Patent Application Publication No. 2019-139925 (Patent Document 1) is known. Patent Document 1 discloses a battery pack comprising: a plurality of battery cells; a housing for housing the battery cells; a plurality of voltage detection wires, one end of which is electrically connected to the electrode terminals of each battery cell; a first connector that gathers the other ends of each voltage detection wire; a second connector inserted into the first connector; and a substrate on which the second connector is mounted, the housing facing the substrate, the first connector being inserted into the second connector along the direction of the substrate opposite to the housing.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2019-139925 Summary of the Invention

[0010] The technical problem that the invention aims to solve

[0011] However, in battery packs that include multiple voltage sensing wires, there are cases where the copper wire constituting the voltage sensing wire branches into another copper wire midway when viewed from the direction of the bus electrode connection terminal. Therefore, it is preferable to avoid applying tensile loads or repetitive loads to the voltage sensing wires leading to the bus electrode connection terminal, which could cause excessive or repetitive movement of the branch portion, thereby applying unnecessary force to the branch portion.

[0012] In the embodiments described below, voltage sensing wires are used as the subject. However, similar technical problems exist in sensing wires other than voltage sensing wires, such as temperature sensing wires used to detect the temperature of a single battery. Therefore, voltage sensing wires and temperature sensing wires can also be generalized and referred to as "condition sensing wires".

[0013] The purpose of this invention is to provide a battery pack with a highly reliable state detection wire.

[0014] Means for solving technical problems

[0015] The present invention is characterized by comprising: a plurality of stacked single cells; and a state detection wire having a first state detection wire and a second state detection wire, the first state detection wire having a state detection terminal for detecting the state of each of the single cells, the second state detection wire branching off from a branch formed midway through the first state detection wire, the plurality of state detection wires including the branch being arranged in the wiring path of a wire storage box, and a foldback redundant length portion being formed in the first state detection wire between the state detection terminal and the branch.

[0016] Furthermore, the present invention is characterized by comprising: a plurality of stacked single cells; and a state detection wire having a first state detection wire, a second state detection wire, and a connecting terminal, wherein the first state detection wire originates from the state detection terminal for detecting the state of each of the single cells, the second state detection wire is connected to the first state detection wire by branching from the middle of the first state detection wire, the connecting terminal is securely crimped to the connection portion of the first state detection wire and the second state detection wire, the state detection wire including the connecting terminal is disposed in the wiring path of the wire storage box, and a foldback redundant length portion is formed in the first state detection wire between the state detection terminal and the connecting terminal.

[0017] Invention Effects

[0018] In this invention, the branch is positioned within the wiring path, thus suppressing branch movement and forming a redundant length section, thereby providing a battery pack with a highly reliable condition detection mechanism. Even under tensile or repetitive loads, forces acting on the branch can be suppressed. Attached Figure Description

[0019] Figure 1 This is an exploded perspective view of a battery pack that utilizes an embodiment of the present invention.

[0020] Figure 2 yes Figure 1 The image shows a top view of the battery pack.

[0021] Figure 3 yes Figure 1 The image shows a side view of the battery pack.

[0022] Figure 4 Viewed from above at an angle Figure 2 A three-dimensional cross-sectional view of the AA section of the battery pack.

[0023] Figure 5 Viewed from above at an angle Figure 2 A three-dimensional cross-sectional view of the BB section of the battery pack.

[0024] Figure 6 This is a 3D view of the cable storage box, voltage detection cable, and busbar from an angle above.

[0025] Figure 7 This is a perspective view of the wire storage box according to an embodiment of the present invention, viewed from an oblique angle, with a portion of it cut off.

[0026] Figure 8 It is Figure 7 The image shown is an enlarged 3D view of the Q section, viewed from an oblique top.

[0027] Figure 9 This is an explanatory diagram illustrating the relationship between the wiring path and the redundant length of the turnaround section. Detailed Implementation

[0028] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below, and various modifications and applications are included within the scope of the technical concept of the present invention. Furthermore, a voltage detection wire will be used as an example to illustrate the status detection wire.

[0029] Before describing the embodiments of the present invention, the structure of the battery pack, which is the subject of the present invention, will be briefly described. Figure 1 This is an exploded perspective view of the battery pack using the embodiments of the present invention, viewed from an oblique top. Figure 2 This is a top view of the battery pack. Figure 3 This is its side view. Figure 4 Viewed from above at an angle Figure 2 A three-dimensional view of section AA. Figure 5 Viewed from above at an angle Figure 2 A three-dimensional cross-sectional view of the BB section. Figure 6 It is a 3D view of the cable management box taken out and viewed from an angle above.

[0030] exist Figures 1-6 In the middle, the housing 11 constituting the battery pack 10 has a generally elongated cuboid shape in which the dimension in the long side direction is larger than the dimension in the short side direction and the height direction, and maintains the battery cluster 12 (see reference). Figure 4 Multiple single cells 13 (refer to) Figure 4 ).

[0031] More specifically, such as Figure 1 As shown, the battery pack of this embodiment includes: a plurality of individual cells 13 (battery clusters); a pair of end plates 15 and side plates 16 surrounding these individual cells 13 from the outside; a bus housing 17 made of synthetic resin covering the upper surface of the individual cells 13; a bus 23 housed in the bus housing 17 and connected to the electrode terminals of the individual cells 13; a wire storage box (also sometimes referred to as a wire harness) 24 for housing a wire harness (also sometimes referred to as a harness) connected to the bus 23 for extracting the detection voltage signal to the outside; and a bus cover 18 fixed to the upper surfaces of the end plates 15 and side plates 16 in a manner that covers the wire harness cover 24, the bus 23, and the bus housing 17.

[0032] Busbar 23 has end busbars 23E at both ends, which can be connected to external motor equipment. Furthermore, the individual battery 13 is held in a battery holder 14 made of synthetic resin. A spacer 31 is provided between the end plate 15 and the individual battery 13, and also between the individual battery 13 and adjacent individual batteries 13. Additionally, an intermediate plate 13M is disposed midway along the length of the plurality of individual batteries 13 stacked along the long side of the side plate 16.

[0033] Single battery 13 Figure 5 As shown, it is formed in a cuboid shape, and on its upper surface, along a direction orthogonal to the stacking direction, a positive terminal 32 (+) and a negative terminal 32 (-) are provided, as is well known. The upper surface is opposite to the busbar housing 17. The single cell 13 includes a container 34 and a cover 35, in which a current collector and electrolyte are housed.

[0034] Furthermore, the cover 35, together with the container 34, seals the current collector and electrolyte. The cover 35 is joined to the container 34. The positive terminal 32 (+) and the negative terminal 32 (-) are mounted on the cover 35. The busbar 23 is welded to the positive terminal 32 (+) and the negative terminal 32 (-) by methods such as ultrasonic welding.

[0035] Furthermore, a gas vent valve 33, serving as a safety valve, is provided on the cover 35 between the positive terminal 32 (+) and the negative terminal 32 (-). When the internal pressure inside the single cell 13 exceeds a specified value, the gas vent valve 33 will crack outward. The gas vent valve 33 is integrally formed with a portion of the cover 35 in a thin-walled form.

[0036] exist Figure 2 , Figure 3 In the middle, the housing 11 includes: a plurality of battery holders 14 for holding a single battery 13 (see reference). Figure 4 ), a pair of end plates 15, a pair of side plates 16, a busbar housing 17, and a busbar cover 18. End plates 15 and side plates 16 are as follows: Figure 3 As shown, it is securely fixed by fastening components such as bolts or rivets. Furthermore, the single cell 13 internally houses battery elements consisting of an electrolyte, a positive electrode layer, and a negative electrode layer. The electrolyte can be either liquid or solid.

[0037] Figure 4 The battery holder 14 shown is made of a resin material such as polybutylene terephthalate (PBT). The battery holder 14 is located between adjacent individual cells 13 of a plurality of individual cells 13 stacked in the longitudinal direction, and holds each individual cell 13 in such a way that it clamps each individual cell 13 from both sides in the thickness direction (the longitudinal direction of the casing).

[0038] A pair of end plates 15 are plate-shaped metal components. These end plates 15 are disposed on both sides of the battery cluster 12, across a pair of battery holders 14 disposed on either side of the battery cluster 12, in the stacking direction of the plurality of individual cells 13 constituting the battery cluster 12. One side of the pair of end plates 15 faces each other in a manner that clamps the plurality of individual cells 13 held by the battery holders 14, and the pair of end plates 15 have a fixing portion on the other side facing outwards on the side opposite to the battery cluster 12.

[0039] The fixing portion 15a provided on a pair of end plates 15 is formed into a generally cylindrical shape, and a portion of the side of the cylinder is provided from the outer plane of the end plate 15 toward the front or rear of the battery pack. The fixing portion 15a has bolt holes along a central axis parallel to the height direction (vertical direction) of the end plate 15.

[0040] The fixing portion 15a of the end plate 15 is a mounting part for fixing the battery pack 10 to an external mechanism such as a vehicle or other machinery. The lower end face of the fixing portion 15a of the end plate 15 is the support surface of the housing 11 supported by such an external mechanism.

[0041] That is, the battery pack 10 is fixed to the external mechanism by the support surface of the housing 11, which serves as the bottom surface of the fixing part 15a of the end plate 15, supported by the external mechanism, and the bolts inserted into the bolt holes of the fixing part 15a are screwed into the internal threads or nuts of the external mechanism. In other words, the battery pack 10 is fixed to the external mechanism by bolts, and is supported by the external mechanism at least on the support surface of the housing 11, which serves as the lower end surface of the fixing part 15a of the end plate 15.

[0042] A pair of side plates 16 are disposed on both sides of the plurality of individual cells 13 constituting the battery cluster 12 in the width direction, separated by the battery retainer 14. The pair of side plates 16 are generally rectangular plate-shaped metal components, disposed on both sides of the housing 11 in the width direction so as to clamp the battery cluster 12 and face each other.

[0043] A pair of side plates 16 are roughly rectangular. The stacking direction of the multiple individual cells 13 constituting the battery cluster 12 is the long side direction, i.e. the length direction. The height direction of the multiple individual cells 13 constituting the battery cluster 12 is the short side direction, i.e. the width direction.

[0044] The two ends of the long sides of the pair of side plates 16 are connected to a pair of end plates 15 by fasteners such as rivets or bolts. The two ends of the short sides of the pair of side plates 16 are engaged with recessed slots provided on the battery holder 14.

[0045] Busbar housing 17 (reference) Figure 1 , Figure 3The busbar housing 17 is a plate-shaped component with specified rigidity made of electrically insulating resin such as PBT, and is disposed opposite to the upper surface of the battery container on which the single cell 13 is provided. Furthermore, the specified rigidity refers to the degree of rigidity to which unnecessary deformation will not occur when the busbar housing 17 is installed in the battery pack 10. That is, the busbar housing 17 only needs to have sufficient rigidity.

[0046] The wire lead-out cylinder 20 protrudes from the upper surface of the busbar cover 18, from which various wire bundles 21a to 21c are led out. Connection sockets 22a to 22c are provided at the front ends of the wire bundles 21a to 21c for connection to a control unit (not shown). The wire bundle 21a used for detecting the voltage of a single battery (hereinafter referred to as the voltage detection wire) 21a in this embodiment is also led out from the wire lead-out cylinder 20. The voltage detection wire 21a is free to move relative to the wire lead-out cylinder 20, and this movement is also transmitted to the voltage detection wire 21a disposed in the wire storage box described later.

[0047] The voltage sensing wire 21a includes a sheathing layer made of an insulating, flexible synthetic resin and a conductive copper wire covered by the sheathing layer. For ease of explanation, the sheathed copper wire, or the copper wire itself, may sometimes be described as a voltage sensing wire.

[0048] like Figure 5 As shown, the busbar housing 17 has: an opening for exposing the upper surfaces of the positive terminals 32(+) and negative terminals 32(-) of a plurality of individual cells 13; and a spacer wall 17W for insulating between the positive terminals 32(+) and negative terminals 32(-) of adjacent individual cells 13 and between adjacent busbars. The spacer wall 19 of the busbar housing 17 is arranged to surround the positive terminals 32(+) and negative terminals 32(-) of the individual cells 13 and the busbars 23.

[0049] Battery cluster 12 (reference) Figure 4 The battery is constructed by stacking flat, rectangular single-cell batteries 13, i.e., thin hexahedral or cuboid-shaped single-cell batteries 13 whose thickness is smaller than their width and height, along the long side of the side plate 16. The single-cell battery 13 is a rectangular lithium-ion battery, comprising: a flat, rectangular battery container; an electrode assembly and electrolyte, or solid electrolyte sheet (not shown), housed inside the battery container; and a pair of battery electrode terminals connected to the electrode assembly and disposed on the upper end face of the battery container in the height direction. Here, as described above, the pair of battery electrode terminals are a positive terminal 32 (+) and a negative terminal 32 (-).

[0050] The pair of battery electrode terminals of the single cell 13 have a generally rectangular three-dimensional shape that protrudes in the height direction from the upper end face of the cover 35 of the battery container. The pair of battery electrode terminals and the battery container, as well as the battery container and the electrode assembly, are electrically insulated by resin insulating components. The plurality of single cells 13 constituting the battery cluster 12 are stacked in an alternating 180° rotation, such that the positive terminal 32 (+) of one adjacent single cell 13 and the negative terminal 32 (-) of another single cell 13 are adjacent in the stacking direction.

[0051] Busbar 23 is a connecting conductor that electrically and mechanically connects multiple individual cells 13 of battery cluster 12, and electrically and mechanically connects battery cluster 12 to external terminals. Busbar 23, which electrically and mechanically connects multiple individual cells 13 of battery cluster 12, is a plurality of busbars that electrically and mechanically connect individual cells 13 to each other, and is joined by welding to the upper end face of the battery electrode terminals of multiple individual cells 13 of battery cluster 12 exposed in the opening of busbar housing 17.

[0052] By electrically connecting the positive terminal of one of a pair of adjacent cells 13 in the stacking direction to the negative terminal of the other cell 13 through a busbar 23, a battery cluster 12 can be formed in which all the cells 13 are connected in series.

[0053] Back Figure 2 The bus cover 18 is a plate-shaped component made of PBT or other electrically insulating resin. It is disposed on the upper end of the housing 11 on the side opposite to the battery cluster 12 in the height direction (vertical direction) of the housing 11, so as to cover the bus cover 17.

[0054] In addition, such as Figure 5 As shown, a wire harness housing 24 extending along the long side of the housing 11 is disposed near the upper center of the housing 11. The wire harness housing 24 includes: an upper plate 24a extending along the long side on the side opposite to the battery cluster 12; and a side plate 24b extending along the long side connected to the upper plate 24a. Between the upper plate 24a and the side plate 24b, a wire harness storage section (also sometimes referred to as a wire wiring path) 24c extending along the long side is formed as a wiring storage space.

[0055] The top plate 24a and the two side plates 24b are arranged to surround the wiring path 24c from three sides, above and from the sides. Multiple voltage detection wires 21a are housed within the wiring path 24c. Furthermore, an opening (through hole) 30 is formed on the top plate 24a, which allows the discharged gas to diffuse when the gas discharge valve formed on the upper surface of the single cell 13 is opened.

[0056] exist Figure 6 The diagram illustrates the structure of the wire harness housing 24, the voltage detection wire 21a, and the electrode connection terminal (also a status detection terminal / voltage detection terminal) 25 for detecting voltage status. The wire harness housing 24 is formed of synthetic resin and includes an upper plate 24a, a pair of side plates 24b connected to the upper plate 24a at a 90° angle, and a wire wiring path 24c formed by these plates (see reference). Figure 7 , Figure 8 The wire wiring path 24c is formed in two rows along the long side of the wire harness housing 24, which is consistent with the arrangement direction of the busbars 23 arranged along the long side of the wire harness housing 24.

[0057] On the side plate 24b, voltage detection wires 21a are led out from the wiring path 24c in a manner corresponding to the positions of the battery electrode terminals on which the single cell 13 is disposed, and each voltage detection wire 21a is engaged with the electrode engagement terminal 25. The led-out voltage detection wires 21a are held inside the wire holder 26, and the wire holder 26 is fixedly held on the side plate 24b.

[0058] Additionally, the voltage detection wire 21a is pre-connected to the electrode connection terminal 25 via a secure electrical connection and mechanical connection. The electrode connection terminal 25 is electrically connected to the busbar 23 by ultrasonic welding. This ultrasonic welding is performed after the harness housing 24 is mounted on the upper side of the battery cluster 12.

[0059] The aforementioned wiring path 24c has the following characteristics: The wiring path 24c extends along the stacking direction of the single cells 13. Furthermore, the wiring path 24c extends along the direction between the positive terminal 32 (+) and the negative terminal 32 (-) of the single cell 13. Additionally, the wiring path 24c is formed at a position farther from the end of the single cell 13 than the positive terminal 32 (+) or the negative terminal 32 (-), that is, it is disposed between the positive terminal 32 (+) and the negative terminal 32 (-) of the single cell 13. Furthermore, the wiring path 24c is disposed on both sides of the gas vent valve 33, which opens when the internal pressure of the battery exceeds a predetermined value, along the stacking direction of the single cells 13 (the long side direction of the side plate 16). Moreover, an opening 30 is formed in the harness housing 24 at a position corresponding to the gas vent valve 33.

[0060] In the structure described above, the voltage sensing wire sometimes employs a wiring structure in which the copper wire constituting the voltage sensing wire 21a branches into another copper wire when viewed from the electrode connection terminal 25 connected to the busbar 23. Furthermore, for example, to ensure a reliable wiring connection for this branch portion, a connecting terminal is used to join the copper wires of the branch portion together.

[0061] However, the connecting terminals clamp the copper wires of the branch sections together, thus compressing the copper wires. Therefore, it is desirable that when excessive tensile or repetitive loads are applied to the voltage sensing wire 21a leading to the electrode connection terminal 25 connected to the busbar 23, the branch sections of the connecting terminals do not move excessively or repeatedly, thereby applying unnecessary stress to the branch sections. In particular, in products such as battery packs, it is desirable to reliably measure battery voltage during the charge and discharge control of the battery pack.

[0062] To address this technical problem, this embodiment proposes a battery pack including a voltage detection wire having a first voltage detection wire, a second voltage detection wire, and a connecting terminal. The first voltage detection wire starts from an electrode connection terminal used for detecting the voltage of each individual cell. The second voltage detection wire is connected to the first voltage detection wire by branching off from the middle of the first voltage detection wire. The connecting terminal is securely crimped to the connection portion of the first and second voltage detection wires. The voltage detection wire including the connecting terminal is arranged in the wiring path of a wire storage box. Furthermore, a folded-back redundant length portion is formed in the first voltage detection wire between the electrode connection terminal and the connecting terminal.

[0063] Furthermore, for example, the battery pack of this embodiment is characterized by having: a battery cluster formed by stacking individual cells with their positive or negative electrode terminals facing one side; voltage detection wires for detecting the voltage of the individual cells; and a wire storage box having a wiring path for storing a plurality of voltage detection wires, wherein the voltage detection wires have: a first voltage detection wire connected to an electrode engagement terminal for detecting the voltage of one individual cell and connected to a first output portion; a branch formed in the middle of the first voltage detection wire; and a second voltage detection wire branching from the branch portion and connected to a second output portion, wherein the plurality of voltage detection wires includes a voltage detection wire having a foldback redundant length portion formed between the electrode engagement terminal of the first voltage detection wire and the branch portion.

[0064] The wiring path extends along the first direction of the single cell stack, and the first state detection wire, the second state detection wire, the branch section and the redundant length section are housed in the wiring path.

[0065] Below, based on Figure 7 and Figure 8 The embodiments of the present invention will be described. Figure 7 This diagram shows only the wire harness housing 24 being pulled out. Figure 8 It is Figure 7 The diagram shows an enlarged view of section Q. Section Q is shown with a portion of side plate 24b cut off; the wire retainer is also omitted.

[0066] exist Figure 6 Within the wiring path 24c formed by the upper plate 24a and a pair of side plates 24b of the harness housing 24, voltage detection wires 21a connected to multiple electrode terminals 25 are housed. These voltage detection wires 21a are then collected in the wire lead-out tube 20 and led out to the outside, where they connect to the connection socket 22a.

[0067] One side of the voltage detection wire 21a is connected to the electrode connection terminal 25, and the first voltage detection wire 21a1 is connected to the connection socket 22a, which is the first output, via the connecting terminal 27, which is a branch. The second voltage detection wire 21a2, which branches from the connecting terminal 27 formed in the middle of the first voltage detection wire 21a1, is connected to the connection socket 22b, which is the second output.

[0068] In addition, this embodiment describes an example of outputting a signal from an electrode connection terminal 25 from connection socket 22a and connection socket 22b, but it is also possible for connection socket 22a to have an output terminal from the first voltage detection wire 21a1 and an output terminal from the second voltage detection wire 21a2.

[0069] Furthermore, regarding the first voltage detection wire 21a1, the wiring on both the electrode connection terminal 25 side and the connection socket 22a side of the branch are described above as the first voltage detection wire 21a1. This also includes voltage detection wires that are not only composed of continuous wiring, but also voltage detection wires obtained by joining different wirings through a defined branch and connecting them to the connection socket.

[0070] The wire wiring path 24c formed in the wire harness housing 24 is, as described above, a slot with a "コ"-shaped cross-section formed by the side plate 24b and the top plate 24a, in which multiple voltage detection wires 21a are arranged. Figure 7 The document provides an explanation of this state.

[0071] exist Figure 7 In the wiring path 24c, a plurality of voltage detection wires 21a are arranged. Among these voltage detection wires 21a, there is a first voltage detection wire (first copper wire) 21a1 that is fastened and connected to the electrode connection terminal 25. The voltage detection wire 21a1 takes the electrode connection terminal 25 as the "starting point" and branches off midway by connecting with another second voltage detection wire (second copper wire) 21a2.

[0072] In this joining section, the cladding layer is stripped away, and the individual copper wires are wound together. Furthermore, at the branch section of this branch, a connecting terminal 27 is securely crimped at the connection point of the copper wires of the first voltage detection wire 21a1 and the second voltage detection wire 21a2. Alternatively, the first and second copper wires can be joined not by winding, but by each copper wire being joined together by a connecting terminal 27 including two secure crimping portions; this also allows for electrical bonding.

[0073] A first voltage detection wire 21a1 and a second voltage detection wire 21a2, including a connecting terminal 27, are disposed in the wiring path 24c. Therefore, the connecting terminal 27, together with the plurality of voltage detection wires 21a, is disposed in the space between a pair of side plates 24b forming the wiring path 24c. Thus, even if repeated external forces are applied to the voltage detection wires 21a from the connection socket 22a side and act on the connecting terminal 27, movement of the connecting terminal 27 can be suppressed by the action of the side plates 24b of the wiring path 24c.

[0074] Furthermore, the first voltage detection wire 21a1 leading to the junction terminal 27 and the electrode connection terminal 25 has a folded-back redundant length portion 28 formed in the space between the opposing side plates 24b of the wire wiring path 24c.

[0075] exist Figure 9 The length of the redundancy section 28 is shown in the figure. Figure 9 In the middle, between the side plates 24b forming the wire wiring path 24c, a first voltage detection wire 21a1 and a second voltage detection wire 21a2 are arranged, and a splicing terminal 27 is provided at their branch portions. Furthermore, the first voltage detection wire 21a1 extending from the splicing terminal 27 is turned back midway so as to extend back to the splicing terminal 27.

[0076] Furthermore, midway to the connector terminal 27, the first voltage detection wire 21a1 is led outward from the lead-out slot 29 formed on the side plate 24b. The led-out first voltage detection wire 21a1 is securely connected to the electrode connection terminal 25. The length (L) of the foldback redundant length portion 28 is from point (P) to point (R), and is set to be longer than the length (W) of the wire wiring path 24c in the width direction (between the opposing side plates). In addition, points (P) and (R) are positions corresponding to the locations where the lead-out slot 29 exists.

[0077] The length (L) of the redundant length section 28 is from point (P) to point (R) and is accommodated in a manner that is longer than the length (W) of the wire wiring path 24c in the width direction (between the opposite side plates).

[0078] Therefore, even if a tensile force is applied to the voltage detection wire 21a from the connection socket 22a side, causing the connecting terminal 27 to move, the connecting terminal 27 can move by folding back the redundant length portion 28. By absorbing the tensile force, the voltage detection wire 21a1 can be prevented from being cut.

[0079] Furthermore, it can reliably output the detected signal, thus enabling the provision of a highly reliable battery pack. Additionally, by efficiently utilizing the space of the wiring path, it can output a highly reliable signal in a compact structure, thus enabling the provision of a highly reliable battery pack.

[0080] Furthermore, while this embodiment focuses on voltage sensing wires, the technical solution of this invention can also be applied to sensing wires other than voltage sensing wires, such as temperature sensing wires used to detect the temperature of a single battery. Therefore, voltage sensing wires and temperature sensing wires can be generalized and referred to as "state sensing wires." Additionally, the electrode connection terminal connected to the busbar and the temperature sensing terminal connected to the thermistor can be considered as state sensing terminals.

[0081] Furthermore, in this embodiment, a splicing terminal is used at the branch, but other connection methods may also be used depending on the purpose.

[0082] As described above, the present invention is characterized by comprising: a plurality of stacked single cells; and a status detection wire having a first status detection wire, a second status detection wire, and a connecting terminal, wherein the first status detection wire starts from the status detection terminal for detecting the status of each single cell, the second status detection wire is connected to the first status detection wire in a manner that branches off from the middle of the first status detection wire, the connecting terminal is securely crimped to the connection portion of the first status detection wire and the second status detection wire, the status detection wire including the connecting terminal is disposed in the wiring path of the wire storage box, and a foldback redundant length portion is formed in the first status detection wire between the status detection terminal and the connecting terminal.

[0083] According to this structure, the splice terminal is arranged in the wire wiring path, thus suppressing the movement of the splice terminal, and forming a folded-back redundant length section, so that even if excessive tensile load or repeated load is applied, wire breakage can be prevented.

[0084] Furthermore, for example, the present invention is characterized by having: a battery cluster formed by stacking individual cells with either the positive or negative electrode terminals facing one side; a state detection wire for detecting the voltage of the individual cells; and a wire storage box having a wiring path for storing a plurality of state detection wires, the state detection wires having: a first state detection wire connected to a state detection terminal for detecting the state of an individual cell and connected to a first output; a branch formed midway through the first state detection wire; and a second voltage detection wire branching from the branch and connected to a second output, wherein the plurality of state detection wires includes a state detection wire having a foldback redundant length portion formed between the state detection terminal and the branch of the first state detection wire.

[0085] The wiring path extends along the first direction of the single cell stack, and the first state detection wire, the second state detection wire, the branch section and the redundant length section are housed in the wiring path.

[0086] This allows for highly reliable output of detected signals, thus enabling the provision of highly reliable battery packs. Furthermore, by housing multiple status detection lines within the wiring path's storage space, a space-saving battery pack can be provided.

[0087] Furthermore, from the viewpoint of space efficiency, it is preferable that the wiring path is formed in the second direction through the positive and negative electrode terminals of the single cell at a position farther from the end of the single cell than the positive or negative electrode terminals.

[0088] The first-state detection wire, the second-state detection wire, the branch section, and the redundant length section can be configured not only within the wire routing path, but also outside the wire routing path.

[0089] Alternatively, the status detection wire may have a third status detection wire without branches. Furthermore, the invention is characterized in that, in the wire routing path, the third status detection wire has a redundant length portion that is shorter than the redundant length portion of the first status detection wire, or a third status detection wire that does not include a redundant length portion.

[0090] Therefore, by making efficient use of the space in the wiring path, it is possible to output signals with high reliability in a small structure, thus enabling the provision of highly reliable battery packs.

[0091] In addition, for example, the single battery has a gas vent valve that opens when the internal pressure of the battery reaches a predetermined value, and the wire storage box has an opening opposite to the gas vent valve along the first direction, including a plurality of wire wiring paths formed along the first direction and arranged on both sides of the opening.

[0092] Therefore, even when the gas discharge valve is open, highly reliable condition measurements of the condition detection line can still be performed.

[0093] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the spirit of the invention as set forth in the claims. For example, the above embodiments have been described in detail to make the present invention easier to understand, and are not necessarily limited to including all the constituent elements described. In addition, a portion of the constituent elements of one embodiment can be replaced with constituent elements of other embodiments, and constituent elements of other embodiments can be added to the constituent elements of one embodiment. Moreover, a portion of the constituent elements of each embodiment can be added, deleted, or replaced with other constituent elements.

[0094] Explanation of reference numerals in the attached figures

[0095] 10…Battery pack, 11…Housing, 12…Battery cluster, 13…Single cell, 14…Battery holder, 15…End plate, 16…Side plate, 17…Bus housing, 18…Bus cover, 20…Wire lead-out tube, 21a, 21a1, 21a2…Voltage detection wire, 22a…Connecting socket, 23…Bus, 24…Wire storage box (wire harness housing), 24a…Top plate, 24b…Side plate, 24c…Wire wiring path (wire harness storage part), 25…Electrode connection terminal, 26…Wire holder, 27…Connection terminal, 28…Foldback redundant length part, 29…Lead-out slot, 30…Opening (through hole), 32 (+)…Positive terminal, 32 (-)…Negative terminal, 33…Gas exhaust valve.

Claims

1. A battery pack, characterized in that, include: Multiple stacked individual cells; and A state detection wire has a first state detection wire and a second state detection wire, the first state detection wire having a state detection terminal for detecting the state of each of the individual cells, and the second state detection wire branching off from a branch formed midway through the first state detection wire. The plurality of status detection wires including the branch are arranged in the wiring path of the wire storage box, and a foldback redundant length is formed in the first status detection wire between the status detection terminal and the branch.

2. The battery pack according to claim 1, characterized in that: The single cell has a positive electrode terminal and a negative electrode terminal, and the single cells are stacked with either the positive electrode terminal or the negative electrode terminal facing one side. The battery pack includes: a status detection wire for detecting the status of the individual cells; and a wire storage box having a wire wiring path for storing multiple status detection wires. The status detection wire has: The first state detection wire is connected to the state detection terminal for detecting the state of one of the single batteries and to the first output unit; The branch formed midway along the first state detection wire; and The second state detection wire, which branches off from the branch section and connects to the second output section, The plurality of state detection wires includes a state detection wire having a foldback redundant length portion formed between the state detection terminal of the first state detection wire and the branch portion. The wiring path extends along the first direction of the single-cell stack. The first state detection wire, the second state detection wire, the branch, and the foldback redundant length are housed in the wire wiring path.

3. The battery pack according to claim 1, characterized in that: The status detection wire is a voltage detection wire.

4. The battery pack according to claim 3, characterized in that: The wiring path of the wire storage box is a storage space surrounded by the top panel of the wire storage box and a pair of side panels connected to the top panel. The first voltage detection wire, the second voltage detection wire, and the branch are housed in the storage space. The length (L) of the foldback redundancy section is set to be longer than the relative lengths (W) of the pair of side plates.

5. A battery pack, characterized in that, include: Multiple stacked individual cells; Busbars are provided in each of the individual cells; A wire storage box arranged along the stacking direction of the single battery; The wiring path formed in the wire storage box; and A voltage sensing wire configured in the wiring path and connected to the electrode connection terminals soldered to the busbar. The voltage detection wire includes at least: a first voltage detection wire originating from the electrode connection terminal; a second voltage detection wire connected to the first voltage detection wire by branching off midway through the first voltage detection wire; and a branch portion that is securely pressed into the connection portion of the first and second voltage detection wires. The voltage sensing wire including the branch is arranged in the wire wiring path of the wire storage box, and a foldback redundant length is formed in the first voltage sensing wire between the electrode connection terminal and the branch.

6. The battery pack according to claim 5, characterized in that: The wiring path of the wire storage box is a storage space surrounded by the top panel of the wire storage box and a pair of side panels connected to the top panel. The first voltage detection wire, the second voltage detection wire, and the branch are housed in the storage space. The length of the foldback redundancy section is set to be longer than the relative lengths of the pair of side plates.

7. The battery pack according to claim 2, characterized in that: The status detection wire is a voltage detection wire.

8. The battery pack according to claim 2, characterized in that: The status detection wire has a third status detection wire that does not have the branch. The wiring path includes a third state detection wire that either includes a return redundancy length portion shorter than the return redundancy length portion of the first state detection wire, or does not include the return redundancy length portion.

9. The battery pack according to claim 2, characterized in that: The single battery has a gas discharge valve that opens when the internal pressure of the battery reaches a specified value. The wire storage box has an opening along the first direction that is opposite to the gas discharge valve. The battery pack includes a plurality of wire routing paths formed along the first direction and disposed on both sides of the opening.

10. The battery pack according to claim 2, characterized in that: The wiring path is formed in a second direction through the positive electrode terminal and the negative electrode terminal of the single cell at a position farther from the end of the single cell than the positive electrode terminal or the negative electrode terminal.

11. A battery pack, characterized in that, include: Multiple stacked individual cells; and A status detection wire includes a first status detection wire, a second status detection wire, and a connecting terminal. The first status detection wire originates from the status detection terminal used to detect the status of each individual battery. The second status detection wire branches off from the first status detection wire and connects to it. The connecting terminal is securely crimped to the connection portion of the first and second status detection wires. The status detection wire including the connecting terminal is disposed in the wiring path of the wire storage box, and a foldback redundant length portion is formed in the first status detection wire between the status detection terminal and the connecting terminal.

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