Battery pack, sub-battery module, and production method for battery pack

Abstract

A battery pack according to the present invention is characterized by comprising a plurality of unit batteries, a busbar 302 that electrically connects terminals of the plurality of unit batteries, voltage detection line terminals 401 that overlap the busbar 302 and are joined to the busbar 302, and a busbar holder 311 that has an installation region for the busbar 302 and the voltage detection line terminals 401, the busbar 302 and the voltage detection line terminals 401 having respective recesses 321a, 321b and 421a, 421b as displacement restriction parts that are provided so as to overlap, and the busbar holder 311 having protrusions 331a, 331b as displacement restriction reception parts that engage the displacement restriction parts and restrict displacement of the busbar 320 and the voltage detection line terminals 401. The present invention thereby provides a battery pack, a sub-battery module, and a production method for a battery pack that make it possible to highly accurately position voltage detection line terminals relative to a busbar.

Description

Battery assembly, sub-battery module, and method of manufacturing battery assembly

[0001] The present invention relates to a battery pack, a sub-battery module, and a method for manufacturing a battery pack.

[0002] 2. Description of the Related Art Conventionally, there has been known a battery pack in which terminals of a plurality of cells are electrically connected by bus bars and which has voltage detection line terminals for measuring the voltage of the cells.

[0003] JP 2018-81875 A

[0004] However, it is not easy to position the voltage detection line terminals relative to the bus bars with high accuracy, which has led to increased manufacturing costs for the battery pack. An object of the present invention is to provide a battery pack, a sub-battery module, and a method for manufacturing a battery pack that enable high-accuracy positioning of the voltage detection line terminals relative to the bus bars.

[0005] In order to solve the above problems, the battery pack of the present invention includes a plurality of cells. The battery pack of the present invention includes a bus bar that electrically connects the terminals of the plurality of cells. The battery pack of the present invention includes a voltage detection line terminal that is arranged on top of the bus bar and joined to the bus bar. The battery pack of the present invention includes a bus bar holder that is provided with mounting areas for the bus bar and the voltage detection line terminal. The bus bar and the voltage detection line terminal each have a displacement restriction portion that is arranged to overlap each other. The bus bar holder has a displacement restriction receiving portion that engages with the displacement restriction portion and restricts displacement of the bus bar and the voltage detection line terminal.

[0006] Alternatively, to solve the above problem, a sub-battery module of the present invention includes bus bars for electrically connecting terminals of a plurality of cells, and a bus bar holder provided with a mounting area for the bus bars. In the sub-battery module of the present invention, displacement restriction portions provided on each bus bar engage with displacement restriction receiving portions provided on the bus bar holder, thereby restricting displacement of the bus bars.

[0007] Alternatively, to solve the above-described problems, a method for manufacturing a battery pack according to the present invention includes a mounting step of arranging a bus bar for electrically connecting terminals of a plurality of cells and a voltage detection line terminal joined to the bus bar in a predetermined mounting area of ​​a bus bar holder, so that the bus bar and the voltage detection line terminal are overlapped with each other. The mounting step also includes a joining step of joining the bus bar and the voltage detection line terminal. The mounting step includes arranging displacement restriction portions formed on the bus bar and the voltage detection line terminal so as to overlap with displacement restriction receiving portions formed on the bus bar holder, which restrict displacement of the bus bar and the voltage detection line terminal, so as to engage with each other.

[0008] According to the present invention, it is possible to provide a battery assembly, a sub-battery module, and a method for manufacturing a battery assembly that enable highly accurate positioning of voltage detection line terminals relative to bus bars.

[0009] 7 is a perspective view showing a battery pack 1 according to an embodiment; FIG. 8 is a perspective view showing components of a battery 100 and a holding unit 200 disassembled in the stacking direction X; FIG. 9 is a perspective view showing the configuration of a busbar unit 300 and a voltage detection unit 400 according to a first embodiment; FIG. 10 is a view of the busbar unit 300 and the voltage detection unit 400 as viewed from the direction IV in FIG. 3; FIG. 11 is a view of the busbar unit 300 and the voltage detection unit 400 as viewed from the direction V in FIG. 3; FIG. 12 is an enlarged view of a portion indicated by VI in FIG. 4; FIG. 13 is a view showing the configuration of a busbar 302 and a voltage detection line terminal 401; FIG. 14 is a cross-sectional view taken along the line VIII-VIII in FIG. 7; FIG. 15 is a view showing a displacement restriction portion of a busbar 302b; FIG. 16 is a view showing a displacement restriction portion of a voltage detection line terminal 401; and FIG. 17 is a view showing the ratio (b / a) of the depth / protrusion length (b) to the width (a) of recesses 321a, 321b, 421a, and 421b. 11A is a view showing the state in which the bus bars 302a, 302b and the voltage detection line terminal 401 are fitted into the bus bar holder 311, as viewed from the direction IV in FIG. 3. FIG. 11B is a view showing the state in which the bus bars 302a, 302b and the voltage detection line terminal 401 are arranged in the bus bar holder 311, as viewed from the direction V in FIG. 3. (a)-(b) are diagrams showing the displacement restriction portion and the displacement restriction receiving portion of the second embodiment. (a)-(b) are diagrams showing the voltage detection line terminal 401, as viewed from the direction XII in FIG. 11.

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0011] <Overall Description of Battery Assembly 1> The configuration of the battery assembly 1 according to the embodiment will be described with reference to FIGS. 1 and 2. Embodiments of the present invention will be described with reference to the drawings. To facilitate understanding of each embodiment, the size and proportions of components may be exaggerated in each drawing. The same reference numerals are used for the same components in each drawing. In each drawing, the stacking direction X, width direction Y, and height direction Z of the battery assembly 1 are indicated by arrows. However, in each drawing, the stacking direction X, width direction Y, and height direction Z of the battery assembly 1 indicate the relative positional relationship within the same drawing. That is, if the battery assembly 1 is rotated 180 degrees and the top and bottom surfaces are reversed, or if the battery assembly 1 is rotated 90 degrees and the top surface is placed as a side, the stacking direction X, width direction Y, and height direction Z of the battery assembly 1 will change. In each drawing, the threads on the outer surfaces of the fastening bolts and the grooves on the inner surfaces of the insert nuts are omitted.

[0012] The configuration of a battery pack 1 according to an embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a perspective view showing the battery pack 1 according to an embodiment. Fig. 2 is a perspective view showing the components of a battery 100 and a holding unit 200 disassembled in the stacking direction X.

[0013] The battery pack 1 is configured as, for example, a power source for operating a motor for running a vehicle. The battery pack 1 may also be configured as, for example, a power source for operating electrical equipment mounted on the vehicle.

[0014] 1 , the battery pack 1 includes a plurality of batteries 100, a holding unit 200 that holds the plurality of batteries 100, and a bus bar unit 300 that electrically connects the plurality of batteries 100. The battery pack 1 also includes a voltage detection unit 400 that detects the voltage of the batteries 100, and a temperature measurement unit (not shown) that measures the temperature of the batteries 100.

[0015] (Configuration of Battery 100) The battery 100 is an example of a single cell, and is stacked in the stacking direction X via a holding unit 200. For example, 24 batteries 100 are stacked. The battery 100 is configured, for example, by a lithium ion secondary battery. The battery 100 includes a current collector and an electrolyte. As shown in FIG. 2 , the battery 100 includes a container 101, a lid 102, a positive electrode terminal 103, a negative electrode terminal 104, and a safety valve 105. The components included in the battery 100 will be described below.

[0016] As shown in FIG. 2 , the battery 100 is formed in a rectangular parallelepiped shape. A positive electrode terminal 103 and a negative electrode terminal 104 are provided on an upper surface 100a of the battery 100 along the stacking direction X. The upper surface 100a corresponds to the upper surface of the battery 100 in FIG. 2 . The upper surface 100a is formed in a rectangular shape. The length of the upper surface 100a along the width direction Y of the battery 100 is longer than the length of the upper surface 100a along the stacking direction X of the battery 100. The upper surface 100a faces the busbar unit 300 shown in FIG. 1 . Two side surfaces 100b along the stacking direction X of the battery 100 face each other perpendicularly to the upper surface 100a. The side surfaces 100b are formed in a rectangular shape. The length of the side surfaces 100b along the height direction Z of the battery 100 is longer than the length of the side surfaces 100b along the stacking direction X of the battery 100. Two main surfaces 100 c of the battery 100 that face each other in the stacking direction X are in contact with the cell spacers 202 and the like of the holding unit 200 .

[0017] The current collector of the battery 100 corresponds to a charge / discharge element between which electric power is input and output. The current collector of the battery 100 is configured by winding or stacking a positive electrode and a negative electrode with a separator interposed therebetween. The container 101 contains the current collector and an electrolyte. The lid 102, together with the container 101, seals the current collector and the electrolyte. The lid 102 is joined to the container 101. The positive electrode terminal 103 and the negative electrode terminal 104 relay the input and output of electric power between the current collector and the electrical device. The positive electrode terminal 103 and the negative electrode terminal 104 are attached to the lid 102. The positive electrode terminal 103 of one battery 100 and the negative electrode terminal 104 of the other battery 100, which are adjacent along the stacking direction X, face each other in the stacking direction X, as shown in FIG. 2 . The safety valve 105 ruptures toward the outside of the battery 100 when the internal pressure of the battery 100 exceeds a predetermined value. The safety valve 105 is also called a split valve. The safety valve 105 is provided in the lid 102, for example.

[0018] (Configuration of holding unit 200) The holding unit 200 holds multiple batteries 100. As shown in Fig. 2, the holding unit 200 includes a first end spacer 201, a cell spacer 202, and a second end spacer 203. The holding unit 200 also includes a first end block 211, a second end block 212, an insulating member 221, and an insert nut 222. As shown in Fig. 1, the holding unit 200 also includes a first side plate 231, a second side plate 232, and a fastening bolt 241. The configuration included in the holding unit 200 will be described below.

[0019] As shown in FIG. 2 , the first end spacer 201 is provided between the first end block 211 and the battery 100. The first end spacer 201 contacts the first battery 100 located at one end of the 24 stacked batteries 100. The first end spacer 201 insulates the first end block 211 from the battery 100. The first end spacer 201 covers each side surface of the first end block 211 and the battery 100 along the width direction Y. The first end spacer 201 covers a portion of the side surface 100b of the battery 100 along the stacking direction X. The thickness of the first end spacer 201 along the stacking direction X is sufficiently thinner than the thickness of the battery 100 along the stacking direction X. The first end spacer 201 is formed of an insulating material.

[0020] As shown in FIG. 2 , the cell spacers 202 are provided between adjacent batteries 100. The cell spacers 202 hold and insulate the adjacent batteries 100. The cell spacers 202 cover the main surfaces 100c of the adjacent batteries 100 along the width direction Y and a portion of the side surfaces 100b of the adjacent batteries 100 along the stacking direction X. The thickness of the cell spacers 202 along the stacking direction X is sufficiently thinner than the thickness of the batteries 100 along the stacking direction X. The cell spacers 202 are made of an insulating material.

[0021] As shown in FIG. 2 , the second end spacer 203 is provided between the battery 100 and the second end block 212. The second end spacer 203 contacts the 24th battery 100 located at the other end of the 24 stacked batteries 100. The second end spacer 203 insulates the battery 100 from the second end block 212. The second end spacer 203 covers each side surface of the first end block 211 and the battery 100 along the width direction Y. The second end spacer 203 covers a portion of the side surface 100b of the battery 100 along the stacking direction X. The thickness of the second end spacer 203 along the stacking direction X is sufficiently thinner than the thickness of the batteries 100 along the stacking direction X. The second end spacer 203 is formed of an insulating material.

[0022] As shown in FIG. 2 , the first end block 211 is stacked with the first battery 100 located at one end of the 24 stacked batteries 100 via a first end spacer 201. The first end block 211 extends along a width direction Y that intersects with the stacking direction X of the batteries 100. The first end block 211 is adjacent to the battery 100 located at the end along the stacking direction X and supports the battery 100. The first end block 211 is formed in a rectangular parallelepiped shape extending in the width direction Y. Fastening bolts 241 are screwed into a plurality of screw holes 211m formed on the side surface of the first end block 211 along the width direction Y. As shown in FIG. 1 , the first end block 211 is fixed to the first side plate 231 by the fastening bolts 241. Similarly, the first end block 211 is fixed to the second side plate 232 by the fastening bolts 241. The first end block 211 is formed with insertion holes 211n for inserting bolts or the like for fixing the battery pack 1. The first end block 211 is made of, for example, metal or resin.

[0023] As shown in FIG. 2 , the second end block 212 is stacked with the 24th battery 100 located at the other end of the 24 stacked batteries 100 via a second end spacer 203. The second end block 212 extends along the width direction Y of the batteries 100. The second end block 212 is adjacent to the battery 100 located at the end along the stacking direction X and supports the battery 100. The second end block 212 is formed in a rectangular parallelepiped shape extending in the width direction Y. Fastening bolts 241 are screwed into multiple screw holes formed on the side surface of the second end block 212 along the width direction Y. As shown in FIG. 1 , the second end block 212 is fixed to the first side plate 231 by the fastening bolts 241. Similarly, the second end block 212 is fixed to the second side plate 232 by the fastening bolts 241. The second end block 212 is formed with insertion holes 212n for inserting bolts or the like to secure the battery pack 1. The second end block 212 is formed of, for example, metal or resin.

[0024] 2, the insulating member 221 is inserted into the first end block 211. The insulating member 221 is also inserted into the second end block 212. The insulating member 221 is formed, for example, in a rectangular parallelepiped shape. The insulating member 221 is made of an insulating material.

[0025] The insulating member 221 may be configured as follows. That is, the insulating member 221 may be molded integrally with the first end spacer 201, or may be molded separately from the first end spacer 201 and then joined to the first end spacer 201. In such a case, the first end block 211 has a recess on its surface facing the first end spacer 201 that accommodates the insulating member 221 along the stacking direction X. Similarly, the insulating member 221 may be molded integrally with the second end spacer 203, or may be molded separately from the second end spacer 203 and then joined to the second end spacer 203. In such a case, the second end block 212 has a recess on its surface facing the second end spacer 203 that accommodates the insulating member 221 along the stacking direction X.

[0026] The insert nut 222 is embedded in a recess formed in the upper surface of the insulating member 221. A fastening bolt is anchored to the insert nut 222 via a bus bar that is electrically connected to an external control device, for example.

[0027] 1 , the first side plate 231 is arranged at one end of the stacked batteries 100 in the width direction Y, along the stacking direction X of the stacked batteries 100. The first side plate 231 holds the batteries 100 along the stacking direction X. The first side plate 231 is fixed to the first end block 211 and the second end block 212 by fastening bolts 241.

[0028] 1 , the second side plate 232 is arranged along the stacking direction X of the stacked plurality of batteries 100, at the other end of the plurality of batteries 100 in the width direction Y. The second side plate 232 holds the plurality of batteries 100 along the stacking direction X. The second side plate 232 is fixed to the first end block 211 and the second end block 212 by fastening bolts 241.

[0029] (Configuration of Busbar Unit 300 and Voltage Detection Unit 400) [First Embodiment] Hereinafter, the configurations of the busbar unit 300 and the voltage detection unit 400 will be described with reference to first and second embodiments. FIGS. 3 to 6 are diagrams showing the configurations of the busbar unit 300 and the voltage detection unit 400 according to the first embodiment. Of these, FIG. 3 is a perspective view showing the configurations of the busbar unit 300 and the voltage detection unit 400 according to the first embodiment. FIG. 4 is a diagram showing the busbar unit 300 and the voltage detection unit 400 as viewed from the direction IV in FIG. 3 . It can also be said that FIG. 4 is a diagram showing the busbar unit 300 and the voltage detection unit 400 as viewed from the direction opposite to the Z direction. It can also be said that FIG. 4 is a diagram showing the surface of the busbar unit 300. FIG. 5 is a diagram showing the busbar unit 300 and the voltage detection unit 400 as viewed from the direction V in FIG. 3 . It can also be said that FIG. 5 is a diagram showing the busbar unit 300 and the voltage detection unit 400 as viewed from the Z direction. Furthermore, it can also be said that Fig. 5 is a diagram showing the back surface of the busbar unit 300. Fig. 6 is an enlarged view of a portion indicated by VI in Fig. 4.

[0030] As shown in Figures 3 to 6, the bus bar unit 300 includes a first end bus bar 301, a plurality of bus bars 302, a second end bus bar 303, and a bus bar holder 311. As shown in Figures 3 and 4, the voltage detection unit 400 includes a harness 450. The harness 450 is an assembly that brings together a voltage detection line terminal 401, a voltage detection line 402, a connector 403, and a temperature measurement unit.

[0031] The first end bus bar 301 is joined to the negative terminal 104 (see FIG. 2 ) of the battery 100 that is closest to the first end block 211 among the 24 stacked batteries 100. The bus bar 302 electrically connects the terminals of the plurality of batteries 100. As a result, as shown in FIG. 3 , the bus bar 302 electrically connects one battery 100 to another battery 100 that are adjacent to each other along the stacking direction X. The bus bar 302 joins the positive terminal 103 of one battery 100 that is adjacent to each other along the stacking direction X to the negative terminal 104 (see FIG. 2 ) of the other battery 100 that is adjacent to each other along the stacking direction X. The second end bus bar 303 is joined to the positive terminal 103 of the battery 100 that is closest to the second end block 212 among the 24 stacked batteries 100.

[0032] The busbar holder 311 mounts the busbar 302 and the voltage detection line terminal 401. The busbar holder 311 is provided with mounting areas for the busbar 302 and the voltage detection line terminal 401. The busbar 302 and the voltage detection line terminal 401 are then fitted in an overlapping manner into these mounting areas. The busbar holder 311 is, for example, a resin molded product.

[0033] The voltage detection line terminal 401 is disposed on top of the bus bar 302 and is joined to the bus bar 302. In this way, the voltage detection line terminal 401 detects the voltage of the battery 100. The voltage detection line 402 is joined to the voltage detection line terminal 401, and information on the voltage detected by the voltage detection line terminal 401 is sent to an external control device via a connector 403. The first end bus bar 301, the bus bar 302, the second end bus bar 303, and the voltage detection line terminal 401 are formed from, for example, a clad material in which copper and aluminum are joined together, copper, or aluminum.

[0034] (Configuration of Bus Bar 302 and Voltage Detection Line Terminal 401) FIG. 7 is a diagram showing the configuration of the bus bar 302 and the voltage detection line terminal 401. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. Note that in FIG. 7, the bus bar holder 311 and the bus bar 302 are depicted semi-transparently for ease of understanding. The bus bar 302 is composed of a pair of bus bars 302a and 302b. The bus bars 302a and 302b connect the terminals of the battery 100. In this case, as shown in FIG. 8, for example, the bus bar 302b is connected to the negative electrode terminal 104 as a terminal. In this case, the bus bar 302a is connected to the positive electrode terminal 103 as a terminal. Each bus bar 302a, 302b has three surfaces: a bottom M1 extending along the XY plane; a side M2 ​​extending along the YZ plane from the bottom M1 in the Z direction; and an upper portion M3 extending along the XY plane from the side M2 ​​in the X direction. The upper portions M3 of the bus bars 302a, 302b overlap and are electrically connected. The voltage detection line terminal 401 is connected to the first end bus bar 301, the multiple bus bars 302, and the second end bus bar 303 of the bus bar unit 300, respectively. The voltage detection line terminal 401 is connected to these terminals by, for example, laser welding. As shown in FIG. 8 , the voltage detection line terminal 401 is connected to the surface of the bottom M1 of the bus bar 302b facing opposite the Z direction. As shown in FIG. 7 , the voltage detection line 402 connected to the voltage detection line terminal 401 is arranged so as to extend from the voltage detection line terminal 401 in the direction opposite the Y direction.

[0035] Furthermore, the bus bar 302b and the voltage detection line terminal 401 have displacement restriction portions for more accurate positioning. FIG. 9( a) is a diagram showing the displacement restriction portion of the bus bar 302b. FIG. 9( a) shows the bus bar 302b when viewed in the direction opposite to the Z direction in FIG. 7. FIG. 9( b) is a diagram showing the displacement restriction portion of the voltage detection line terminal 401. FIG. 9( b) shows the voltage detection line terminal 401 when viewed in the direction opposite to the Z direction in FIG. 7. As shown in FIG. 9( a), the bus bar 302b has recesses 321a and 321b formed as displacement restriction portions. As shown in FIG. 9( b), the voltage detection line terminal 401 has recesses 421a and 421b formed as displacement restriction portions. These displacement restriction portions are arranged so that the displacement restriction portions of the bus bar 302 and the displacement restriction portions of the voltage detection line terminal 401 overlap each other when installed in the bus bar holder 311. That is, when installed in busbar holder 311, recessed portions 321a and 421a are in the same position and overlap each other, and recessed portions 321b and 421b are in the same position and overlap each other.

[0036] 9(c), the ratio (b / a) of the depth (b) to the width (a) of the recesses 321a, 321b, 421a, and 421b is preferably not less than 1 / 5 and not more than 4. In this case, the bus bar 302 and the voltage detection line terminal 401 can be positioned with higher precision, and workability during assembly is improved.

[0037] Although the displacement regulating portion is a recessed portion in this example, it may be a protruding portion. Therefore, it can also be said that the displacement regulating portion is a pair of recessed or protruding portions provided on the edges of the bus bar 302 and the voltage detection line terminal 401.

[0038] FIG. 10( a) is a diagram showing the busbars 302a and 302b and the voltage detection line terminal 401 fitted into the busbar holder 311. FIG. 10( a) shows the busbar holder 311, the busbars 302a and 302b, and the voltage detection line terminal 401 as viewed from the direction IV in FIG. 3. FIG. 10( b) is a diagram showing the voltage detection line terminal 401 placed in the busbar holder 311. FIG. 10( b) shows the busbar holder 311 and the voltage detection line terminal 401 as viewed from the direction V in FIG. 3. Note that in FIG. 10( b), the busbar holder 311 is depicted semi-transparently for ease of understanding. The busbar holder 311 has a displacement restriction receiving portion that engages with the displacement restriction portion and restricts the displacement of the busbar 302 and the voltage detection line terminal 401. 10(a) and 10(b), the displacement restriction receiving portions are convex portions 331a and 331b. That is, concave portions 321a and 421a, which are displacement restriction portions, engage with convex portion 331a, which is the displacement restriction receiving portion. On the other hand, concave portions 321b and 421b, which are displacement restriction portions, engage with convex portion 331b, which is the displacement restriction receiving portion. Note that when the displacement restriction portions are convex portions, the displacement restriction receiving portions become concave portions. This allows bus bar 302b and voltage detection line terminal 401 to be positioned in bus bar holder 311 with greater precision.

[0039] 10(b), a joint 340 that joins the bus bar 302b and the voltage detection line terminal 401 is provided between the recessed portions 421a and 421b, which are displacement restriction portions. The joint 340 is provided at a position where the bus bar 302b and the voltage detection line terminal 401 overlap. As described above, the joining is performed by, for example, laser welding, and in this case, the joint 340 is a laser weld mark. In this case, it can also be said that the joint 340 is provided between the recessed portions 321a and 321b, which are displacement restriction portions. Furthermore, in this case, it can also be said that the joint 340 is provided between the protruding portions 331a and 331b, which are displacement restriction receiving portions. In this case, the joining can be performed with greater precision.

[0040] (Configuration of Temperature Measurement Unit) The temperature measurement unit measures the temperature of the battery 100 based on control by, for example, an external control device. The temperature measurement unit includes a temperature sensor and an electric wire.

[0041] (Advantages of the Battery Assembly 1 of the First Embodiment) The advantages of the battery assembly 1 of the first embodiment are described below. A battery assembly 1 can be provided that allows the voltage detection line terminal 401 to be positioned with high precision relative to the bus bar 302. Conventionally, after the voltage detection line terminal 401 is positioned, a load is applied to the harness 450 due to handling during assembly, which can cause the joint 340 of the voltage detection line terminal 401 to deform, making it difficult to maintain contact pressure. On the other hand, by realizing a structure that makes it easy to position the bus bar 302 and the voltage detection line terminal 401, loads are less likely to be generated during assembly, and the joint 340 of the voltage detection line terminal 401 is less likely to deform. In addition, the manufacturing cost of the battery assembly 1 is reduced. A displacement restriction portion can be more easily provided. Joining can be performed with greater precision. Joining workability is improved. The bus bar 302 and the voltage detection line terminal 401 can be positioned with greater precision, and assembly workability is improved.

[0042] Second Embodiment In the first embodiment described above, one of the displacement restriction portion and the displacement restriction receiving portion is a recess and the other is a protrusion, and the bus bar 302 and the voltage detection line terminal 401 are positioned by engaging these portions. However, the configuration of the displacement restriction portion and the displacement restriction receiving portion is not limited to this. In the second embodiment, other examples of the displacement restriction portion and the displacement restriction receiving portion will be described.

[0043] 11(a) and 11(b) are diagrams illustrating the displacement restriction portion and the displacement restriction receiving portion according to the second embodiment. Of these, FIG. 11(a) is a perspective view illustrating the configuration of busbars 302a, 302b and a voltage detection line terminal 401 according to the second embodiment. FIG. 11(b) is a view of the busbars 302a, 302b and the voltage detection line terminal 401 as viewed from the XIb direction in FIG. 11(a). In this case, the displacement restriction portion is a hole 321c formed in the busbar 302b and a recess 421c formed in the voltage detection line terminal 401. Meanwhile, the displacement restriction receiving portion is a pin-shaped protrusion 360 formed on the busbar holder 311. In the second embodiment, the displacement restriction portion is a hole or recess provided in the busbar 302b and the voltage detection line terminal 401, and the displacement restriction receiving portion is the protrusion 360 provided on the busbar holder 311. The projection 360 penetrates and engages with the hole or recess, thereby restricting the displacement of the bus bar 302b and the voltage detection line terminal 401.

[0044] FIG. 12 is a view of the voltage detection line terminal 401 as viewed from the XII direction in FIG. 11 . As shown in the figure, the recess 421c engages with the protrusion 360. A joint 340 that joins the bus bar 302b and the voltage detection line terminal 401 is provided so as to surround the recess 421c. Note that the bus bar holder 311 is depicted semi-transparently in FIG. 12 for ease of understanding. In this case, the joint 340 is a U-shaped weld mark. However, the present invention is not limited to this and may be, for example, a U-shape.

[0045] (Advantages of the Battery Assembly 1 of the Second Embodiment) The advantages of the battery assembly 1 of the second embodiment will be described. It is possible to provide a battery assembly 1 that can accurately position the voltage detection line terminals 401 relative to the bus bars 302. It is possible to maintain electrical connection between the bus bars 302 and the voltage detection line terminals 401.

[0046] (Sub-battery module) In the above example, the battery pack 1 has been described, but the busbar unit 300 can also be considered an invention of a sub-battery module. The following forms are conceivable for the sub-battery module. (1) The busbar 302 is installed in the busbar holder 311, but the voltage detection line terminal 401 is not installed. The user prepares and connects the voltage detection line terminal 401. (2) The busbar 302 and the voltage detection line terminal 401 are arranged in the busbar holder 311. However, they are not yet connected. (3) The busbar 302 and the voltage detection line terminal 401 are arranged in the busbar holder 311. Furthermore, they are already connected.

[0047] The form (1) can be regarded as a sub-battery module that includes bus bars 302 for electrically connecting the terminals of multiple batteries 100 and bus bar holders 311 that have mounting areas for the bus bars 302, and that regulates the displacement of the bus bars 302 by engaging a displacement regulation portion provided on each bus bar 302 with a displacement regulation receiving portion provided on the bus bar holders 311.

[0048] The form (2) is similar to the form (1), but further includes a voltage detection line terminal 401 placed on top of the bus bar 302 in the mounting area. The voltage detection line terminal 401 has a displacement restriction portion that is arranged so that when placed on top of the bus bar 302, it is in the same position as the displacement restriction portion placed on the bus bar 302. The displacement restriction receiving portion of the bus bar holder 311 engages with the displacement restriction portions of both the bus bar 302 and the voltage detection line terminal 401, and restricts the displacement of the voltage detection line terminal 401 in addition to the bus bar 302. This can be considered as a sub-battery module.

[0049] The configuration (3) can be regarded as a sub-battery module in which, in addition to the configuration (2), a joint 340 that joins the bus bar 302 and the voltage detection line terminal 401 is provided.

[0050] (Effects of the Sub-Battery Module) It is possible to provide a sub-battery module that allows for highly accurate positioning of the busbar 302. It is possible to provide a sub-battery module that allows for highly accurate positioning of the voltage detection line terminal 401 relative to the busbar 302. After the busbar 302 and the voltage detection line terminal 401 have been positioned with high accuracy, the busbar 302 and the voltage detection line terminal 401 can be joined in this state.

[0051] (Method for Manufacturing Battery Pack 1) The above-described embodiment can also be considered as an invention of a method for manufacturing the battery pack 1. In this case, the method for manufacturing the battery pack 1 includes the following two steps: (A) a mounting step of arranging bus bars 302 for electrically connecting the terminals of the plurality of batteries 100 and voltage detection line terminals 401 to be joined to the bus bars 302 in a stacked manner in a predetermined mounting area of ​​the bus bar holder 311. (B) a joining step of joining the bus bars 302 and the voltage detection line terminals 401.

[0052] In the placing step (A), displacement restriction portions formed on the bus bar 302 and the voltage detection line terminal 401 and arranged to overlap each other are arranged to engage with displacement restriction receiving portions formed on the bus bar holder 311 and restricting the displacement of the bus bar 302 and the voltage detection line terminal 401. In the joining step (B), the bus bar 302 and the voltage detection line terminal 401 are joined by laser welding or the like.

[0053] (Effects of the manufacturing method of the battery pack 1) The bus bars 302 and the voltage detection line terminals 401 can be positioned with higher precision, and the workability during assembly is improved.

[0054] (Battery Assembly of Other Embodiments) The battery assembly of the present invention is not limited to the configuration of the battery assembly described in the embodiments, and can be configured appropriately based on the content described in the claims.

[0055] The embodiments are described in detail or simply to make the present invention easier to understand, and do not necessarily include all of the components described, or may include components not shown. Also, some of the components of the embodiments may be deleted, replaced with components of other embodiments, or combined with components of other embodiments.

[0056] The number of batteries 100 included in the battery pack 1 is not limited to 24. The batteries 100 are not limited to lithium ion batteries. For example, nickel-metal hydride batteries and lead batteries can be used as the batteries 100. The batteries 100 are not limited to secondary batteries. For example, primary batteries can be used as the batteries 100.

[0057] 1 battery pack (single cell), 200 holding unit, 300 bus bar unit (sub-battery module), 302, 302a, 302b bus bar, 311 bus bar holder, 321a, 321b, 421a, 421b recess (displacement regulation portion), 321c hole portion (displacement regulation portion), 331a, 331b convex portion (displacement regulation receiving portion), 340 joint portion, 360 protrusion portion (displacement regulation receiving portion), 400 voltage detection unit, 401 voltage detection line terminal, 402 voltage detection line

Claims

1. An assembled battery comprising: a plurality of electric cells; a bus bar electrically connecting the terminals of the plurality of electric cells; a voltage detection line terminal arranged on top of and joined to the bus bar; and a bus bar holder provided with a mounting area for the bus bar and the voltage detection line terminal; wherein the bus bar and the voltage detection line terminal each have a displacement restriction portion arranged to overlap each other, and the bus bar holder has a displacement restriction receiving portion that engages with the displacement restriction portion and restricts displacement of the bus bar and the voltage detection line terminal.

2. The battery pack according to claim 1, wherein the displacement restriction portion is a pair of recesses or protrusions provided on the edges of the bus bar and the voltage detection line terminal.

3. The battery pack according to claim 2, wherein a joint portion for joining the bus bar and the voltage detection line terminal is provided between the pair of recessed or protruding portions.

4. The battery pack according to claim 3, wherein the joints are laser welded.

5. The battery pack according to claim 2, wherein the ratio (b / a) of the depth (b) of the recess or protrusion to the width (a) is 1 / 5 or more and 4 or less.

6. The battery pack according to claim 1, wherein the displacement restriction portion is a hole or recess provided in the bus bar and the voltage detection line terminal, and the displacement restriction receiving portion is a protrusion provided in the bus bar holder, and the protrusion penetrates and engages with the hole or recess to restrict displacement of the bus bar and the voltage detection line terminal.

7. The battery pack according to claim 6, wherein a joint portion that joins the bus bar and the voltage detection line terminal is provided so as to surround the displacement restriction portion.

8. A sub-battery module comprising: bus bars for electrically connecting the terminals of a plurality of cells; and a bus bar holder having a mounting area for the bus bars; wherein displacement restriction portions provided on each of the bus bars engage with displacement restriction receiving portions provided on the bus bar holder, thereby restricting displacement of the bus bars.

9. A sub-battery module as described in claim 8, further comprising a voltage detection line terminal placed in the mounting area and overlapping the bus bar, wherein the voltage detection line terminal has a displacement restriction portion arranged so as to be in the same position as the displacement restriction portion placed on the bus bar when placed overlapping the bus bar, and the displacement restriction receiving portion of the bus bar holder engages with the displacement restriction portions of both the bus bar and the voltage detection line terminal, and restricts displacement of the voltage detection line terminal in addition to the bus bar.

10. The sub-battery module according to claim 9, further comprising a joint for joining the bus bar and the voltage detection line terminal.

11. A method for manufacturing a battery pack, comprising: a mounting step of overlapping and arranging a bus bar for electrically connecting the terminals of a plurality of cells and a voltage detection line terminal to be joined to the bus bar in a predetermined mounting area of ​​a bus bar holder; and a joining step of joining the bus bar and the voltage detection line terminal, wherein the mounting step engages displacement restriction portions formed on the bus bar and the voltage detection line terminal and arranged to overlap each other, with displacement restriction receiving portions formed on the bus bar holder and restricting displacement of the bus bar and the voltage detection line terminal.

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