Manufacturing method of battery module

Abstract

This manufacturing method of a battery module is a manufacturing method of a battery module provided with a cell having at least a first electrode, a first bus bar, and a first wire connecting the first electrode and the first bus bar, wherein the cell has a first end surface provided with the first electrode, and a second end surface on the side opposite to the first end surface, and the first bus bar is positioned more on a side opposite to the second end surface than the first end surface of the cell. The manufacturing method comprises: connecting the first bus bar and one end of the first wire; and after connecting the first bus bar and the one end of the first wire, connecting the first electrode of the cell and the other end of the first wire.

Description

Battery module manufacturing method

[0001] The present invention relates to a method for manufacturing a battery module.

[0002] For example, Patent Document 1 discloses a battery module in which electrode terminals of battery cells are electrically connected to bus bars by wire bonding.

[0003] JP 2019-114389 A

[0004] Because a battery module includes many cells, the manufacturing process of the battery module requires many wire bonding operations to connect the electrodes of the cells to the bus bars.

[0005] Therefore, an object of the present invention is to provide a method for manufacturing a battery module that can improve the workability of wire bonding in the battery module.

[0006] In order to solve the above problem, one embodiment of the present invention provides a battery module manufacturing method including: a battery module including a cell having at least a first electrode, a first bus bar, and a first wire connecting the first electrode and the first bus bar; wherein the cell has a first end face on which the first electrode is provided and a second end face opposite the first end face; the first bus bar is located on the opposite side of the second end face of the cell than the first end face; and the method includes connecting the first bus bar and one end of the first wire; and, after connecting the first bus bar and one end of the first wire, connecting the first electrode of the cell to the other end of the first wire.

[0007] According to the present invention, it is possible to improve the workability of wire bonding in a battery module.

[0008] Fig. 1 is a perspective plan view conceptually showing an example of the configuration of a battery module according to this embodiment. Fig. 2 is a longitudinal sectional view showing an enlarged view of the periphery of one cell. Fig. 3 is a schematic diagram showing an example of a bonding system. Fig. 4 is a longitudinal sectional view showing an enlarged view of the periphery of one cell during a wire bonding process. Fig. 5 is a flowchart explaining the flow of the wire bonding process in the manufacturing process of a battery module.

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for facilitating understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0010] 1 is a perspective plan view conceptually illustrating an example of the configuration of a battery module 1 according to this embodiment. In FIG. 1, the Z direction indicates the height direction of the battery module 1, the X direction indicates the length direction of the battery module 1, and the Y direction indicates the width direction of the battery module 1.

[0011] The battery module 1 may be mounted on a vehicle such as an electric vehicle equipped with a motor generator as a drive source. The vehicle is not limited to an electric vehicle, but may also be a hybrid electric vehicle equipped with a motor generator and an engine as a drive source. The battery module 1 is not limited to being mounted on a vehicle, but may also be mounted on various devices.

[0012] The battery module 1 includes a plurality of cells 10, a plurality of first bus bars 12, a plurality of second bus bars 14, a plurality of first wires 16a, a plurality of second wires 16b, a plurality of third wires 16c, and a plurality of fourth wires 16d. Note that the numbers of the cells 10, the first bus bars 12, the second bus bars 14, the first wires 16a, the second wires 16b, the third wires 16c, and the fourth wires 16d are not limited to the numbers illustrated in FIG. 1 and may vary depending on the specifications of the battery module 1. Hereinafter, the first bus bars 12 and the second bus bars 14 may be collectively referred to simply as bus bars without distinction. The first wires 16a, the second wires 16b, the third wires 16c, and the fourth wires 16d may be collectively referred to simply as wires without distinction.

[0013] The cell 10 is a single cell of a rechargeable secondary battery such as a lithium ion battery. The cell 10 is formed in a cylindrical shape, but is not limited to a cylindrical shape and may be formed in various shapes such as a rectangular pillar shape.

[0014] Each of the multiple cells 10 is arranged upright so as to extend in the height direction (Z direction in FIG. 1 ) of the battery module 1. Each of the multiple cells 10 is also arranged in a predetermined arrangement in the length direction (X direction in FIG. 1 ) and width direction (Y direction in FIG. 1 ) of the battery module 1. Note that the specific arrangement of the multiple cells 10 is not limited to the example shown in FIG. 1 .

[0015] The cell 10 has a first electrode 20 and a second electrode 22. The first electrode 20 and the second electrode 22 are made of conductive materials. The first electrode 20 is, for example, a positive electrode, and the second electrode 22 is, for example, a negative electrode. Depending on the type of cell 10, the first electrode 20 may be a negative electrode and the second electrode 22 may be a positive electrode. Hereinafter, the first electrode 20 and the second electrode 22 may be collectively referred to simply as electrodes without distinction.

[0016] The first electrode 20 and the second electrode 22 are provided at one end of the cell 10 in the extension direction (Z direction in FIG. 1 ). As shown in FIG. 1 , the first electrode 20 is formed in a circular shape. The second electrode 22 is formed in an annular shape concentric with the first electrode 20 and is disposed on the outer periphery of the first electrode 20. The radial width of the second electrode 22 is narrower than the radial width of the first electrode 20. In other words, the length between the inner and outer circles of the second electrode 22 is shorter than the length between the center and circumference of the first electrode 20. The area of ​​the second electrode 22 is narrower than the area of ​​the first electrode 20.

[0017] The first bus bar 12 and the second bus bar 14 are formed in a sheet or plate shape from a conductive material. For example, the first bus bar 12 and the second bus bar 14 may be formed from a metal sheet containing aluminum. The first bus bar 12 and the second bus bar 14 may be supported by a structure such as a predetermined cover member that surrounds the periphery of the multiple cells 10.

[0018] The first bus bar 12 is formed into a specific first shape, and the second bus bar 14 is formed into a specific second shape that is different from the first shape of the first bus bar 12.

[0019] 1 , the first bus bar 12 may be formed into a first shape by a first portion 30 extending in the width direction of the battery module 1 and a second portion 32 extending from the first portion 30 at a central portion in the extension direction of the first portion 30. Note that the first shape is not limited to the shape exemplified in FIG. 1 , and may be various shapes depending on the specifications of the battery module 1.

[0020] 1 , the second bus bar 14 may be formed into a second shape by a first portion 30 extending in the width direction of the battery module 1 and a third portion 34 extending from both ends of the first portion 30 in the extension direction of the first portion 30. The second shape is not limited to the shape exemplified in FIG. 1 , and may be any shape as long as it is at least different from the first shape, and may be various shapes depending on the specifications of the battery module 1.

[0021] In this way, the battery module 1 includes bus bars of two different shapes. The reason for providing bus bars of two different shapes is to achieve desired structural characteristics, such as the arrangement of the cells 10 and the bus bars, and desired electrical characteristics, such as the voltage of the battery module 1. Note that the battery module 1 is not limited to including bus bars of two different shapes, and may include bus bars of at least multiple shapes, and may include bus bars of three or more shapes.

[0022] The first bus bars 12 and the second bus bars 14 are alternately arranged along a predetermined direction in which the cells 10 are arranged. For example, the first bus bars 12 and the second bus bars 14 may be alternately arranged along the longitudinal direction of the battery module 1 (the X direction in FIG. 1 ). The first bus bars 12 and the second bus bars 14 are also arranged at a distance so as not to contact each other. The first bus bars 12 and the second bus bars 14 are arranged such that at least a portion of the first electrode 20 and at least a portion of the second electrode 22 fit within an area obtained by projecting the space between the first bus bar 12 and the second bus bar 14 in a direction toward the cells 10.

[0023] The wire is a conductive wire material. The wire electrically connects either the first electrode 20 or the second electrode 22 of the cell 10 to either the first bus bar 12 or the second bus bar 14. That is, in the battery module 1, the electrodes and the bus bars are connected by wire bonding using the wire. Wire bonding will be described in detail later.

[0024] The plurality of cells 10 are divided into a plurality of first groups 40 and a plurality of second groups 42. In the example of Fig. 1 , among the plurality of cells 10, the cells 10 located to the right of the first bus bar 12 and to the left of the second bus bar 14 belong to the first group 40. In other words, the first bus bar 12 corresponding to a cell 10 belonging to the first group 40 is located to the left of the cell 10, and the second bus bar 14 corresponding to the cell 10 is located to the right of the cell 10.

[0025] 1 , among the multiple cells 10, the cell 10 located to the right of the second bus bar 14 and to the left of the first bus bar 12 belongs to the second group 42. In other words, the first bus bar 12 corresponding to the cell 10 belonging to the second group 42 is located to the right of the cell 10, and the second bus bar 14 corresponding to the cell 10 is located to the left of the cell 10.

[0026] As described above, since the first bus bars 12 and the second bus bars 14 are arranged alternately, there are a plurality of first groups 40 and a plurality of second groups 42, which are arranged alternately.

[0027] The first electrode 20 of each cell 10 belonging to the first group 40 is connected to the first bus bar 12 by a first wire 16a. The second electrode 22 of each cell 10 belonging to the first group 40 is connected to the second bus bar 14 by a second wire 16b. As a result, the cells 10 belonging to each first group 40 are connected in parallel.

[0028] The first electrode 20 of each cell 10 belonging to the second group 42 is connected to the second bus bar 14 by a third wire 16c. The second electrode 22 of each cell 10 belonging to the second group 42 is connected to the first bus bar 12 by a fourth wire 16d. As a result, the cells 10 belonging to each second group 42 are connected in parallel.

[0029] Since the first bus bars 12 and the second bus bars 14 are alternately arranged, the parallel-connected cells 10 of the first group 40 and the parallel-connected cells 10 of the second group 42 are alternately connected in series. That is, in the example of Fig. 1 , the parallel-connected cells 10 arranged in the width direction of the battery module 1 are connected in parallel, and the parallel-connected cells 10 are connected in series in the length direction of the battery module 1.

[0030] Although not shown in the drawings, of the alternately arranged first bus bars 12 and second bus bars 14, the bus bars arranged at both ends are electrically connected to electrode terminals of the battery module 1. As a result, a voltage is generated between the two electrode terminals of the battery module 1 by the plurality of cells 10 electrically connected as described above.

[0031] 2 is an enlarged longitudinal cross-sectional view showing the periphery of one cell 10. In FIG. 2, one of the plurality of cells 10 belonging to the first group 40 is illustrated.

[0032] 2, the cell 10 has a first end face 50 on one side in the extension direction of the cell 10 (the Z direction in FIG. 2), and a second end face 52 on the opposite side to the first end face 50. The first electrode 20 and the second electrode 22 are provided on the first end face 50. In addition, a predetermined plate 54 that supports the cell 10 may be provided on the second end face 52 of the cell 10.

[0033] The first bus bar 12 and the second bus bar 14 are located on the opposite side of the first end face 50 of the cell 10 from the second end face 52, and are spaced apart from the first end face 50. The distance from the first end face 50 of the first bus bar 12 in the extension direction of the cell 10 is approximately the same as the distance from the first end face 50 of the second bus bar 14 in the extension direction of the cell 10.

[0034] One end of the first wire 16a is connected to a surface 56 of the first bus bar 12 opposite the cell 10. The other end of the first wire 16a is connected to the first electrode 20 on the first end surface 50 of the cell 10.

[0035] The first wire 16a has a smooth curved shape that connects the surface 56 of the first bus bar 12 and the first electrode 20. More specifically, the portion of the first wire 16a near the first bus bar 12 has a greater curve than the portion of the first wire 16a near the first electrode 20.

[0036] One end of the second wire 16b is connected to a surface 58 of the second bus bar 14 opposite the cell 10. The other end of the second wire 16b is connected to the second electrode 22 on the first end surface 50 of the cell 10.

[0037] The second wire 16b has a smooth curved shape that connects the surface 58 of the second bus bar 14 and the second electrode 22. More specifically, the portion of the second wire 16b near the second bus bar 14 has a greater curve than the portion of the second wire 16b near the second electrode 22.

[0038] Although not shown, for the cells 10 in the second group 42, the first bus bar 12 and the second bus bar 14 are located on the opposite side of the first end face 50 of the cell 10 from the second end face 52, and are spaced apart from the first end face 50. The portion of the third wire 16c near the second bus bar 14 is more curved than the portion of the third wire 16c near the first electrode 20. The portion of the fourth wire 16d near the first bus bar 12 is more curved than the portion of the fourth wire 16d near the second electrode 22.

[0039] The connection between the busbar and the wire, and the connection between the electrode and the wire are, for example, ultrasonic bonding, but may also be soldering, welding, or any other known connection method.

[0040] (Wire Bonding) Fig. 3 is a schematic diagram showing an example of a bonding system 100. The bonding system 100 realizes the wire bonding process in the manufacturing process of the battery module 1. Hereinafter, for convenience of explanation, the battery module 1 under manufacturing that is the target of the wire bonding operation may be referred to as the target module 102. Fig. 3 shows an example of a state in which connection by the first wire 16a has been made.

[0041] The bonding system 100 includes a stage 110 , an imaging device 112 , a bonding device 114 and a control device 120 .

[0042] The stage 110 includes a platform on which the target module 102 can be placed. In Fig. 3 , the Z direction indicates the vertical direction of the stage 110, the X direction indicates a predetermined direction in the horizontal direction of the stage 110, and the Y direction indicates a direction perpendicular to the X direction in the horizontal direction of the stage 110. The stage 110 may include an actuator that can move in any of the X, Y, and Z directions. The target module 102 is placed on the stage 110 so that the bus bars and electrodes face upward in the vertical direction.

[0043] The imaging device 112 is configured to be able to capture an image of at least a portion of the target module 102 on the stage 110 .

[0044] The bonding device 114 is configured to be able to perform wire bonding, for example, by ultrasonic bonding, at a predetermined position on the target module 102 on the stage 110. The bonding device 114 includes an arm that handles and connects the wire used for wire bonding. The bonding device 114 can move the tip of the arm to any position within a predetermined range on the stage 110.

[0045] The control device 120 includes one or more processors and one or more memories connected to the processors. The memories include a ROM in which programs and the like are stored and a RAM as a work area. The processors work in conjunction with the programs stored in the memories to execute various processes.

[0046] The control device 120 can control the movement of the stage 110 according to a program. The control device 120 can also acquire images captured by the imaging device 112. By executing the program, the control device 120 controls the bonding device 114 based on the acquired images. For example, the control device 120 analyzes the acquired images to identify the position where connection should be performed. The control device 120 then controls the movement of the stage 110, the movement of the arm in the bonding device 114, the handling of the wire, the execution of connection, and the like.

[0047] 4 is an enlarged vertical cross-sectional view showing the periphery of one cell 10 during the wire bonding process. In FIG. 4, one of the plurality of cells 10 belonging to the first group 40 is shown.

[0048] 4, the cell 10 is placed on the stage 110 so that the first end face 50 on which the electrodes are located is positioned vertically higher than the second end face 52. Also, as shown in FIG. 4, the bonding device 114 connects the wires from the side opposite the cell 10 from the first bus bar 12 and the second bus bar 14.

[0049] 5 is a flowchart illustrating the flow of the wire bonding process in the manufacturing process of the battery module 1. Hereinafter, for convenience of explanation, the manufacturing method of the battery module 1 of this embodiment may be referred to as the present manufacturing method. The control device 120 starts the series of processes in FIG. 5 when the target module 102 is placed on the stage 110 and an instruction to start wire bonding is received, or when a predetermined timing for starting wire bonding arrives.

[0050] First, the control device 120 performs first bonding (S10) to connect, by wire bonding, any one of the plurality of first bus bars 12 to the first electrode 20 of any one of the plurality of cells 10. In the first bonding, the first electrode 20 of the cell 10 belonging to the first group 40 is connected to the first bus bar 12 corresponding to the cell 10 belonging to the first group 40 by a first wire 16a (see FIG. 1 ).

[0051] More specifically, the control device 120 acquires an image from the imaging device 112. The control device 120 analyzes the acquired image and calibrates the position of the arm relative to the position of each cell 10. The control device 120 identifies the position of the first electrode 20 and the position of the first bus bar 12 of the cell 10 that is to undergo the first bonding, among the cells 10 that belong to the first group 40. The control device 120 controls the bonding device 114 to perform the first bonding on the first electrode 20 of the identified cell 10 and the identified first bus bar 12.

[0052] In the first bonding, the control device 120 controls the bonding device 114 to connect the surface 56 of the identified first bus bar 12 to one end of the first wire 16a (S11). After connecting the identified first bus bar 12 to one end of the first wire 16a, the control device 120 connects the first electrode 20 of the identified cell 10 to the other end of the first wire 16a connected to the first bus bar 12 (S12). As a result, the identified first bus bar 12 and the first electrode 20 of the identified cell 10 are connected by the first wire 16a.

[0053] As described above, in this manufacturing method, after connecting one end of the first bus bar 12 to one end of the first wire 16a, the first electrode 20 of the cell 10 is connected to the other end of the first wire 16a. In other words, in this manufacturing method, the connection to the first bus bar 12 that is located relatively closer to the bonding device 114 among the first bus bars 12 and cells 10 is performed relatively earlier (see FIG. 4 ). In other words, in this manufacturing method, the connection to the first bus bar 12 that is located relatively farther from the bonding device 114 among the first bus bars 12 and cells 10 is performed relatively later.

[0054] In this manufacturing method, by performing the first bonding in this order, it is possible to improve the workability of handling the first wire 16a in the bonding device 114 and the workability of connection.

[0055] For example, when connecting the end of the first wire 16a, a straight portion of the first wire 16a near the end to be connected is required for the arm to grip the first wire 16a. As a comparative example, let us assume that the connection between the first bus bar 12 and the first wire 16a is performed relatively later than the connection between the first electrode 20 and the first wire 16a. In this case, when connecting the end of the first wire 16a to the first bus bar 12, the bending of the first wire 16a near the first bus bar 12 becomes large, making it difficult for the arm to grip the first wire 16a. Therefore, in this comparative example, the workability of handling the first wire 16a is reduced when connecting the first bus bar 12 side of the first wire. As a result, in this comparative example, the shape of the first wire 16a after both ends are connected may not be a smooth curve, the length of the first wire 16a may be unnecessarily long, or the speed of the connection work may be reduced.

[0056] In contrast, in the present manufacturing method, the connection between the first electrode 20 and the first wire 16a is performed relatively earlier on the side of the first bus bar 12, where the bending of the first wire 16a is greater. As a result, in the present manufacturing method, the first wire 16a can be connected to the first bus bar 12 before bending the first wire 16a, i.e., after the first wire 16a is straightened. Therefore, in the present manufacturing method, the ease of handling when the arm grips the first wire 16a when connecting the end of the first wire 16a to the first bus bar 12 can be improved. As a result, in the present manufacturing method, the shape of the first wire 16a whose both ends are connected can be made into a smooth curve, which can prevent the length of the first wire 16a from becoming unnecessarily long and can prevent a decrease in the speed of the connection work.

[0057] After both ends of the first wire 16a are connected, the portion of the first wire 16a near the first electrode 20 is less curved than the portion of the first wire near the first bus bar 12 (see FIG. 4 ). For this reason, in the present manufacturing method, even if the connection on the first electrode 20 side of the cell 10 is performed relatively later, the first wire 16a can be connected to the first electrode 20 while being kept in a straight state. Therefore, in the present manufacturing method, even if the connection on the first electrode 20 side of the cell 10 is performed relatively later, the ease of handling when the arm grips the first wire 16a is not reduced when connecting the end of the first wire 16a to the first electrode 20.

[0058] The control device 120 identifies the cell 10 on which the first bonding is to be performed and performs the first bonding sequentially for the cells 10 belonging to the first group 40. At this time, in the first bonding of each cell 10, the control device 120 connects one end of the first wire to the first bus bar 12 as described above, and then connects the first electrode 20 of the cell 10 to the other end of the first wire.

[0059] The control device 120 may sequentially perform the first bonding on the cells 10 belonging to one first group 40 until the first bonding on all the cells 10 belonging to that one first group 40 is completed.

[0060] The control device 120 may be configured to sequentially perform the first bonding in a direction from the first group 40 at one end of the direction in which the first bus bars 12 and the second bus bars 14 are alternately arranged among the multiple first groups 40 to the first group 40 at the other end.

[0061] In this way, the control device 120 performs first bonding for all cells 10 in the multiple first groups 40, in other words, for all first bus bars 12 corresponding to the cells 10 in the multiple first groups 40.

[0062] After completing the first bonding for the plurality of first bus bars 12, the control device 120 starts second bonding (S20) to connect by wire bonding any one of the plurality of second bus bars 14 to the first electrode 20 of any one of the plurality of cells 10. In the second bonding, the first electrode 20 of the cell 10 belonging to the second group 42 is connected to the second bus bar 14 corresponding to the cell 10 belonging to the second group 42 by a third wire 16c (see FIG. 1 ).

[0063] More specifically, the control device 120 acquires an image from the imaging device 112. The control device 120 analyzes the acquired image and calibrates the position of the arm relative to the position of each cell 10. The control device 120 identifies the positions of the first electrodes 20 and the second bus bars 14 of the cells 10 belonging to the second group 42 for which the second bonding is to be performed. The control device 120 controls the bonding device 114 to perform the second bonding on the first electrodes 20 of the identified cells 10 and the identified second bus bars 14.

[0064] In the second bonding, the control device 120 controls the bonding device 114 to connect the surface 58 of the identified second bus bar 14 to one end of the third wire 16c (S21). After connecting the identified second bus bar 14 to one end of the third wire 16c, the control device 120 connects the first electrode 20 of the identified cell 10 to the other end of the third wire 16c connected to the second bus bar 14 (S22). As a result, the identified second bus bar 14 and the first electrode 20 of the identified cell 10 are connected by the third wire 16c.

[0065] In this manner, in this manufacturing method, after connecting one end of the second bus bar 14 to one end of the third wire 16c, the first electrode 20 of the cell 10 is connected to the other end of the third wire 16c. In other words, in this manufacturing method, the connection to the second bus bar 14 that is located relatively closer to the bonding device 114 among the second bus bars 14 and cells 10 is performed relatively first.

[0066] In this manufacturing method, by performing the second bonding in this order, it is possible to improve the ease of handling and connection of the third wire 16c in the bonding device 114, as with the first bonding.

[0067] Furthermore, as described above, in this manufacturing method, the second bonding is started after the first bonding is completed for a plurality of first bus bars 12. In other words, in this manufacturing method, a plurality of first bondings that share a common combination of the type of bus bar to be connected and the type of electrode are performed collectively and continuously.

[0068] As a result, in this manufacturing method, substantially the same operations are continuously and repeatedly performed, which simplifies the program of the control device 120 for controlling the bonding device 114. Therefore, in this manufacturing method, the burden of teaching the bonding device 114 the details of the wire bonding process can be reduced.

[0069] Furthermore, since the radial width of the first electrode 20 is wider than the radial width of the second electrode 22, when connecting a wire to the first electrode 20, the error from a specific position at which the wire is connected is allowed to be larger than in the case of the second electrode 22. For this reason, when connecting a wire to the first electrode 20, the positional accuracy of the connection position by the bonding device 114 may be lower than in the case of the second electrode 22.

[0070] In this manufacturing method, the first bonding that connects the first electrodes 20, which are wider than the second electrodes 22, to the first bus bar 12 is performed continuously all at once. As a result, this manufacturing method can eliminate the process of calibrating the connection positions by the bonding device 114 through image analysis. This manufacturing method can reduce the frequency of calibrating the connection positions, thereby improving the speed of the wire bonding work.

[0071] For example, in this manufacturing method, calibration of the connection position using image analysis may be performed before the initial first bonding, and then the calibration may not be performed until the first bonding is completed for multiple first bus bars 12.

[0072] Returning to the explanation of the second bonding, the control device 120 identifies the cell 10 on which the second bonding is to be performed and performs the second bonding sequentially for the cells 10 belonging to the second group 42. At this time, in the second bonding of each cell 10, the control device 120 connects one end of the second bus bar 14 to the third wire 16c as described above, and then connects the first electrode 20 of the cell 10 to the other end of the third wire 16c.

[0073] The control device 120 may sequentially perform the second bonding on the cells 10 belonging to one second group 42 until the second bonding on all the cells 10 belonging to that one second group 42 is completed.

[0074] The control device 120 may perform the second bonding sequentially in a direction from the second group 42 at one end of the direction in which the first bus bars 12 and the second bus bars 14 are alternately arranged among the multiple second groups 42 to the second group 42 at the other end.

[0075] In this way, the control device 120 performs second bonding for all cells 10 in the multiple second groups 42, in other words, for all second bus bars 14 corresponding to the cells 10 in the multiple second groups 42.

[0076] After completing the second bonding for the plurality of second bus bars 14, the control device 120 starts third bonding (S30) to connect by wire bonding any one of the plurality of second bus bars 14 to the second electrode 22 of any one of the plurality of cells 10. In the third bonding, the second electrode 22 of the cell 10 belonging to the first group 40 is connected to the second bus bar 14 corresponding to the cell 10 belonging to the first group 40 by the second wire 16b (see FIG. 1 ).

[0077] More specifically, the control device 120 acquires an image from the imaging device 112. The control device 120 analyzes the acquired image and calibrates the position of the arm relative to the position of each cell 10. The control device 120 identifies the position of the second electrode 22 and the position of the second bus bar 14 of the cell 10 that is to undergo the third bonding among the cells 10 that belong to the first group 40. The control device 120 controls the bonding device 114 to perform the third bonding on the second electrode 22 of the identified cell 10 and the identified second bus bar 14.

[0078] In the third bonding, the control device 120 controls the bonding device 114 to connect the surface 58 of the identified second bus bar 14 to one end of the second wire 16b (S31). After connecting the identified second bus bar 14 to one end of the second wire 16b, the control device 120 connects the second electrode 22 of the identified cell 10 to the other end of the second wire 16b connected to the second bus bar 14 (S32). As a result, the identified second bus bar 14 and the second electrode 22 of the identified cell 10 are connected by the second wire 16b.

[0079] In this manner, in this manufacturing method, after connecting one end of the second bus bar 14 to one end of the second wire 16b, the second electrode 22 of the cell 10 is connected to the other end of the second wire 16b. In other words, in this manufacturing method, the connection to the second bus bar 14 that is located relatively closer to the bonding device 114 among the second bus bars 14 and cells 10 is performed relatively first.

[0080] In this manufacturing method, by performing the third bonding in this order, it is possible to improve the ease of handling and connection of the second wire 16b in the bonding device 114, as with the first bonding.

[0081] Furthermore, as described above, in this manufacturing method, the third bonding is started after the second bonding is completed for a plurality of second bus bars 14. In other words, in this manufacturing method, a plurality of second bondings that share a common combination of the type of bus bar to be connected and the type of electrode are performed collectively and continuously.

[0082] As a result, in this manufacturing method, substantially the same operations are continuously and repeatedly performed, which simplifies the program of the control device 120 for controlling the bonding device 114. Therefore, in this manufacturing method, the burden of teaching the bonding device 114 the details of the wire bonding process can be reduced.

[0083] Furthermore, in this manufacturing method, the third bonding is started after the first bonding is completed for the plurality of first bus bars 12 and the second bonding is completed for the plurality of second bus bars 14. In other words, in this manufacturing method, the third bonding, which includes connecting wires to the second electrodes 22, is started after the connection of wires to the first electrodes 20 is completed for all of the cells 10 included in the battery module 1.

[0084] In this manufacturing method, wires are connected to the first electrodes 20, which do not require as high positional accuracy as the second electrodes 22, all at once. This makes it possible to eliminate the need for image analysis to calibrate the connection positions of the bonding device 114. This manufacturing method reduces the frequency of calibration of the connection positions, thereby improving the speed of the wire bonding process.

[0085] For example, in this manufacturing method, calibration of the connection position by image analysis may be performed before the first second bonding, and then the calibration may not be performed until the second bonding is completed for multiple second bus bars 14.

[0086] Returning to the explanation of the third bonding, the control device 120 identifies the cell 10 on which the third bonding is to be performed and performs the third bonding sequentially for the cells 10 belonging to the first group 40. At this time, in the third bonding of each cell 10, the control device 120 connects one end of the second bus bar 14 to the second wire 16b, as described above, and then connects the second electrode 22 of the cell 10 to the other end of the second wire 16b.

[0087] The control device 120 may sequentially perform the third bonding on the cells 10 belonging to one first group 40 until the third bonding is completed on all the cells 10 belonging to that one first group 40.

[0088] The control device 120 may be configured to sequentially perform the third bonding in a direction from the first group 40 at one end of the direction in which the first bus bars 12 and the second bus bars 14 are alternately arranged among the multiple first groups 40 to the first group 40 at the other end.

[0089] In this way, the control device 120 performs third bonding for all cells 10 in the multiple first groups 40, in other words, for all second bus bars 14 corresponding to the cells 10 in the multiple first groups 40.

[0090] In addition, since the third bonding involves connecting a wire to the second electrode 22, which is narrower than the first electrode 20, the frequency of calibrating the connection position using image analysis may be more frequent than in the first and second bonding.

[0091] After completing the third bonding for the plurality of second bus bars 14, the control device 120 starts the fourth bonding (S40) to connect by wire bonding any one of the plurality of first bus bars 12 to the second electrode 22 of any one of the plurality of cells 10. In the fourth bonding, the second electrode 22 of the cell 10 belonging to the second group 42 is connected to the first bus bar 12 corresponding to the cell 10 belonging to the second group 42 by a fourth wire 16d (see FIG. 1 ).

[0092] More specifically, the control device 120 acquires an image from the imaging device 112. The control device 120 analyzes the acquired image and calibrates the position of the arm relative to the position of each cell 10. The control device 120 identifies the position of the second electrode 22 and the position of the first bus bar 12 of the cell 10 that is to undergo the fourth bonding among the cells 10 that belong to the second group 42. The control device 120 controls the bonding device 114 to perform the fourth bonding on the second electrode 22 of the identified cell 10 and the identified first bus bar 12.

[0093] In the fourth bonding, the control device 120 controls the bonding device 114 to connect the surface 56 of the identified first bus bar 12 to one end of the fourth wire 16d (S41). After connecting the identified first bus bar 12 to one end of the fourth wire 16d, the control device 120 connects the second electrode 22 of the identified cell 10 to the other end of the fourth wire 16d connected to the first bus bar 12 (S42). As a result, the identified first bus bar 12 and the second electrode 22 of the identified cell 10 are connected by the fourth wire 16d.

[0094] In this manner, in this manufacturing method, after connecting one end of the first bus bar 12 to one end of the fourth wire 16d, the second electrode 22 of the cell 10 is connected to the other end of the fourth wire 16d. In other words, in this manufacturing method, the connection to the first bus bar 12 that is located relatively closer to the bonding device 114 among the first bus bar 12 and the cell 10 is performed relatively first.

[0095] In this manufacturing method, by performing the fourth bonding in this order, it is possible to improve the ease of handling and connection of the fourth wire 16d in the bonding device 114, as with the first bonding.

[0096] Furthermore, as described above, in this manufacturing method, the fourth bonding is started after the third bonding is completed for a plurality of second bus bars 14. In other words, in this manufacturing method, a plurality of third bondings that share a common combination of the type of bus bar to be connected and the type of electrode are performed collectively and continuously.

[0097] As a result, in this manufacturing method, substantially the same operations are continuously and repeatedly performed, which simplifies the program of the control device 120 for controlling the bonding device 114. Therefore, in this manufacturing method, the burden of teaching the bonding device 114 the details of the wire bonding process can be reduced.

[0098] Furthermore, in this manufacturing method, the fourth bonding is started after the third bonding, which is performed after the first bonding has been completed for the plurality of first bus bars 12 and the second bonding has been completed for the plurality of second bus bars 14. In other words, in this manufacturing method, the fourth bonding, which includes connecting wires to the second electrodes 22, is started after the connection of wires to the first electrodes 20 has been completed for all of the cells 10 included in the battery module 1.

[0099] In this manufacturing method, wires are connected to the first electrodes 20, which do not require as high positional accuracy as the second electrodes 22, all at once. This makes it possible to eliminate the need for image analysis to calibrate the connection positions of the bonding device 114. This manufacturing method reduces the frequency of calibration of the connection positions, thereby improving the speed of the wire bonding process.

[0100] In addition, since the fourth bonding involves connecting a wire to the second electrode 22, which is narrower than the first electrode 20, the frequency of calibrating the connection position using image analysis may be higher than in the first and second bonding.

[0101] Returning to the explanation of the fourth bonding, the control device 120 identifies the cell 10 on which the fourth bonding is to be performed and performs the fourth bonding sequentially for the cells 10 belonging to the second group 42. At this time, in the fourth bonding of each cell 10, the control device 120 connects one end of the fourth wire 16d to the first bus bar 12, as described above, and then connects the second electrode 22 of the cell 10 to the other end of the fourth wire 16d.

[0102] The control device 120 may sequentially perform the fourth bonding on the cells 10 belonging to one second group 42 until the fourth bonding on all the cells 10 belonging to that one second group 42 is completed.

[0103] The control device 120 may perform the fourth bonding sequentially in a direction from the second group 42 at one end of the direction in which the first bus bars 12 and the second bus bars 14 are alternately arranged among the multiple second groups 42 to the second group 42 at the other end.

[0104] In this way, the control device 120 performs the fourth bonding for all the cells 10 in the second groups 42, in other words, for all the first bus bars 12 corresponding to the cells 10 in the second groups 42. This completes the wire bonding operation.

[0105] Note that the example described here is one in which the third bonding is started after the first and second bonding are completed, and the fourth bonding is started after the third bonding is completed. However, the control device 120 may be configured to start the fourth bonding after the first and second bonding are completed, and start the third bonding after the fourth bonding is completed. In other words, the control device 120 may be configured to start at least one of the third and fourth bonding after completing the first bonding for the plurality of first bus bars 12 and the second bonding for the plurality of second bus bars 14.

[0106] In this embodiment as well, wires are connected in a batch continuously to the first electrodes 20, which do not require as high positional accuracy in the connection position as the second electrodes 22. Therefore, in this embodiment as well, the frequency of calibration of the connection position can be reduced, thereby improving the speed of the wire bonding operation.

[0107] In addition, in this manufacturing method, the third and fourth bonding are performed after the first and second bonding are completed, so that the first group 40 and the second group 42 are connected in parallel, and then the series connection of each group is performed. In other words, in this manufacturing method, the parallel connection is performed first, and then the series connection is performed.

[0108] As a result, in this manufacturing method, the voltage in each group can be stabilized by connecting them in parallel, and each group is connected in series with a stable voltage, thereby stabilizing the electrical characteristics of the battery module 1 after manufacture.

[0109] As described above, the battery module 1 of the present embodiment includes a plurality of cells 10 having first electrodes 20 and second electrodes 22, a plurality of first bus bars 12 having a first shape, and a plurality of second bus bars 14 having a second shape different from the first shape. The manufacturing method for the battery module 1 of the present embodiment includes performing a first bonding process for the plurality of first bus bars 12, in which any one of the plurality of first bus bars 12 is connected to the first electrode 20 of any one of the plurality of cells 10 by wire bonding. The manufacturing method for the battery module 1 of the present embodiment includes, after completing the first bonding process for the plurality of first bus bars 12, starting a second bonding process for connecting any one of the plurality of second bus bars 14 to the first electrode 20 of any one of the plurality of cells 10 by wire bonding.

[0110] As a result, in the manufacturing method of the battery module 1 of this embodiment, substantially the same operations are continuously repeated, thereby reducing the burden of teaching the bonding device 114 the wire bonding process. Furthermore, in the manufacturing method of the battery module 1 of this embodiment, the first bonding that connects the first electrodes 20, which are wider than the second electrodes 22, to the first bus bars 12 is performed continuously all at once, thereby reducing the frequency of calibration of the connection positions and improving the speed of the wire bonding operation. Therefore, the manufacturing method of the battery module 1 of this embodiment makes it possible to improve the workability of wire bonding in the battery module 1.

[0111] The battery module 1 of this embodiment also includes a cell 10 having at least a first electrode 20, a first bus bar 12, and a first wire 16a connecting the first electrode 20 and the first bus bar 12. The cell 10 has a first end surface 50 on which the first electrode 20 is provided and a second end surface 52 opposite the first end surface 50. The first bus bar 12 is located on the opposite side of the second end surface 52 from the first end surface 50 of the cell 10. The manufacturing method for the battery module 1 of this embodiment includes connecting the first bus bar 12 and one end of the first wire 16a. The manufacturing method for the battery module 1 of this embodiment also includes connecting the first bus bar 12 and one end of the first wire 16a, and then connecting the first electrode 20 of the cell 10 to the other end of the first wire 16a.

[0112] As a result, in the manufacturing method for the battery module 1 of the present embodiment, connection to the first bus bar 12 that is located relatively closer to the bonding device 114 among the first bus bars 12 and the cells 10 is performed relatively first. As a result, in the manufacturing method for the battery module 1 of the present embodiment, it is possible to improve the ease of handling and connection of the first wires 16a in the bonding device 114. Therefore, according to the manufacturing method for the battery module 1 of the present embodiment, it is possible to improve the ease of wire bonding in the battery module 1.

[0113] While the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present invention.

[0114] REFERENCE SIGNS LIST 1 battery module 10 cell 12 first bus bar 14 second bus bar 16a first wire 16b second wire 20 first electrode 22 second electrode 50 first end surface 52 second end surface

Claims

1. A method for manufacturing a battery module including a cell having at least a first electrode, a first bus bar, and a first wire connecting the first electrode and the first bus bar, wherein the cell has a first end face on which the first electrode is provided and a second end face opposite the first end face, and the first bus bar is located on the opposite side of the second end face of the cell than the first end face of the cell, the method including: connecting the first bus bar to one end of the first wire; and, after connecting the first bus bar to one end of the first wire, connecting the first electrode of the cell to the other end of the first wire.

2. The method for manufacturing a battery module according to claim 1, wherein the cell further has a second electrode, and the battery module further comprises: a second bus bar; and a second wire connecting the second electrode and the second bus bar, wherein the second electrode is provided on the first end surface on which the first electrode is provided, the radial width of the second electrode is narrower than the radial width of the first electrode, and the second bus bar is located on the opposite side of the first end surface of the cell from the second end surface, and after connecting the first bus bar and the first electrode with the first wire, connecting the second bus bar and one end of the second wire, and after connecting the second bus bar and one end of the second wire, connecting the second electrode of the cell and the other end of the second wire.

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