Battery pack manufacturing equipment

Abstract

To provide a manufacturing apparatus suitable for pressing a plurality of pressurizing pieces against a plurality of bus bars at the same time.SOLUTION: A battery pack includes a plurality of battery cells stacked in a first direction, each battery cell has a terminal on a surface facing a second direction intersecting the first direction, and a bus bar is welded to the terminal. A manufacturing apparatus includes a plurality of pressurizing pieces arranged side by side along the first direction, the tip of the pressurizing piece in the second direction facing each terminal with the bus bar being interposed therebetween, a rotor that extends along the first direction and is rotated by an actuator and engaged with the plurality of pressuring pieces, when rotated around its axis, the rotor pushing the plurality of pressuring pieces toward the bus bars, and a welder for welding the bas bars and the terminals. In the manufacturing apparatus, the welder welds the bus bars to the terminals while the rotor presses the bus bars against the terminals.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The technology disclosed in this specification relates to an apparatus for manufacturing a battery pack. [Background technology]

[0002] The assembled battery includes a plurality of battery cells stacked in a first direction. Each battery cell includes a terminal on a surface facing a second direction intersecting the first direction, and a bus bar is welded to the terminal. The assembled battery and a manufacturing device thereof are disclosed in Patent Document 1. A bus bar is welded to the terminal of the battery cell. The manufacturing device disclosed in Patent Document 1 welds the bus bar to the terminal while pressing the bus bar against the terminal with a jig. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 130705 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to quickly weld multiple bus bars, it is preferable to press the bus bars against multiple terminals at the same time and weld each bus bar to each terminal. The manufacturing device has multiple pressure pieces that face the multiple terminals with the bus bars in between. A large force is required to press the multiple pressure pieces against the multiple bus bars at the same time. If a beam supported at both ends is translated and pressed against the multiple pressure pieces, the beam will bend significantly due to the reaction force from the pressure pieces. This specification provides a manufacturing device that is suitable for pressing multiple pressure pieces against multiple bus bars at the same time. [Means for solving the problem]

[0005] In describing the manufacturing apparatus disclosed in this specification, a battery pack will first be described. The battery pack includes a plurality of battery cells stacked in a first direction. Each battery cell includes a terminal on a surface facing a second direction intersecting the first direction, and a bus bar is welded to the terminal. The manufacturing apparatus disclosed in this specification includes a plurality of pressure pieces aligned along the first direction and having tips in the second direction facing the respective terminals with the bus bar in between, a rotor extending along the first direction and rotated by an actuator, the rotor engaging with the plurality of pressure pieces and pushing the plurality of pressure pieces toward the bus bar when rotating around an axis, and a welder that welds the bus bar to the terminal. The welder welds the bus bar to the terminal while the rotor presses the bus bar against the terminal.

[0006] When the rotor rotates, the reaction force of the force pushing the multiple pressure pieces is distributed into a translational force pushing the rotor and a moment to twist the rotor. Since the reaction force of the force pushing the multiple pressure pieces is received by the flexural rigidity and torsional rigidity of the rotor, the deflection of the rotor is smaller than when multiple pressure pieces are pressed by a translating beam. The manufacturing device disclosed in this specification is suitable for pressing multiple pressure pieces against multiple bus bars simultaneously.

[0007] One example of a rotor has a shaft that rotates with an actuator and a number of abutment pieces that engage with the shaft. Each of the abutment pieces abuts against a corresponding pressure piece. It is preferable that the engagement points between the abutment pieces and the shaft are distributed around the shaft when viewed from the first direction. The moment applied to the shaft from the abutment pieces is applied evenly around the shaft.

[0008] A spring may be interposed between the shaft and each of the abutment pieces. The spring has elasticity in the circumferential direction of the shaft. Even if there is a positional error of the bus bars in the second direction, a load is applied to each bus bar evenly.

[0009] An example of the abutting piece is a pinion gear, in which case the pressure piece may include a rack gear that engages with the pinion gear.

[0010] Details and further improvements of the technology disclosed in this specification are described in the following "Forms for Carrying Out the Invention". [Brief description of the drawings]

[0011] [Figure 1] FIG. [Diagram 2] FIG. 2 is a perspective view of two battery cells, a separator, and a bus bar. [Diagram 3] FIG. 2 is a front view of the battery pack manufacturing apparatus. [Figure 4] FIG. [Diagram 5] FIG. 4 is an explanatory diagram of forces acting on a rotor. [Figure 6] FIG. 2 is a diagram illustrating the forces that each of the four pinion gears applies to the shaft. [Figure 7] FIG. 13 is a front view of a manufacturing apparatus according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Prior to describing the manufacturing apparatus of the embodiment, the battery pack 2 will be described. FIG. 1 shows a perspective view of the battery pack 2. The battery pack 2 has a structure in which a plurality of battery cells 10 and a plurality of separators 20 are alternately stacked one by one. In FIG. 1, reference numerals are omitted for some of the battery cells and some of the separators. Also, in FIG. 1, the central portion of the battery pack 2 is not shown. Furthermore, reference numerals 10a, 10b, and 10c are used to individually represent the three battery cells 10 on the right side of FIG. 1. The X direction of the coordinate system in FIG. 1 corresponds to the stacking direction of the plurality of battery cells 10. In the following figures, the X direction of the coordinate system in the figures corresponds to the stacking direction.

[0013] End plates 40 are attached to both ends of the stack of battery cells 10 and separators 20. The stack of battery cells 10, separators 20, and end plates 40 is bound together with a band or a frame and housed in a case. The band or frame and case are not shown in the illustration.

[0014] A positive electrode terminal 11p and a negative electrode terminal 11n are provided on one surface of the battery cell 10 (the surface facing the +Z direction in the coordinate system in the figure). The multiple battery cells 10 are arranged so that the positive electrode terminals 11p and the negative electrode terminals 11n are alternately arranged in the stacking direction (X direction). The positive electrode terminal 11p of the battery cell 10a at the right end of FIG. 1 is connected to the negative electrode terminal 11n of the adjacent battery cell 10b by a bus bar 30 (30a). The positive electrode terminal 11p of the battery cell 10b is connected to the negative electrode terminal 11n of the adjacent battery cell 10c by a bus bar 30 (30b). In this way, all the battery cells 10 are connected in series by connecting the positive electrode terminals 11p and the negative electrode terminals 11n of the adjacent battery cells 10. Although not shown in the figure, the end plate 40 is provided with a positive electrode terminal and a negative electrode terminal at the end of the series connection of the multiple battery cells 10.

[0015] In the following description, when there is no need to distinguish between the positive terminal 11p and the negative terminal 11n, they will be referred to as terminals 11. The terminals 11 adjacent to each other in the X direction are connected by a bus bar 30.

[0016] FIG. 2 shows oblique views of a battery cell 10, a separator 20, and a bus bar 30. The separator 20 is made of resin. The separator 20 includes a partition plate 21 that is sandwiched between adjacent battery cells 10 (10a, 10b). The partition plate 21 is rectangular and includes a frame 22 that extends along three sides except for the top side 21a. The frame 22 is provided on both sides of the partition plate 21. The battery cell 10 fits into the frame 22. One of the frames 22 on both sides of the partition plate 21 is designed so that the battery cell 10 is press-fitted into it, and the other is designed to be larger (wider) than one of the frames 22 so that the battery cell 10 can be loosely fitted into it.

[0017] The partition plate 21 is provided with a lip 25 that abuts against the bottom surface of the battery cell 10 fitted into the frame 22. The lip 25 is an elastic protrusion that bends in the vertical direction. The lip 25 supports the battery cell 10 fitted into the frame 22 from below.

[0018] A rib 23 extends upward from the upper side 21a of the partition plate 21. When viewed from the X direction (stacking direction) in the figure, a slit 24 is provided between each of the left and right ends of the rib 23 and the upper side 21a of the partition plate 21. When viewed from the X direction, the slit 24 has a U-shape that is closed at the top and bottom and at the center side of the separator 20 in the left and right directions.

[0019] The bus bar 30 is generally U-shaped and has two arms 31a, 31b and a bottom 32 that connects the arms 31a, 31b. The bus bar 30 is made of a metal plate. The terminals 11 of the battery cells 10 are also made of metal, and the bus bar 30 and the terminals 11 are joined by welding.

[0020] The bus bar 30 is supported by being sandwiched in the slit 24. More specifically, the plate-shaped bottom portion 32 of the bus bar 30 is inserted into the slit 24 from the horizontal direction (the Y direction in the coordinate system in the drawing).

[0021] One bus bar 30 is attached to one separator 20. In Fig. 2, the bus bar 30 (30a) is attached to the slit 24 on the right side of the separator 20, and therefore the bus bar 30 (30b) cannot be attached to the slit 24 on the left side (in Fig. 2, the bus bar 30 (30b) that cannot actually be attached is drawn with an imaginary line). In another separator 20, the bus bar 30 (30b) is attached to the slit 24 on the left side, and the bus bar 30 (30a) cannot be attached to the slit 24 on the right side.

[0022] The manufacturing apparatus 100 for the battery pack 2 will now be described. Fig. 3 shows a front view of the manufacturing apparatus 100, and Fig. 4 shows a plan view of the manufacturing apparatus 100. A stack of multiple battery cells 10 and multiple separators 20 is set in the manufacturing apparatus 100. The stack is not shown in Fig. 4. In Figs. 3 and 4 as well, the X direction of the coordinate system corresponds to the stacking direction of the multiple battery cells 10 and the multiple separators 20. Each separator 20 holds a bus bar 30.

[0023] The manufacturing apparatus 100 is an apparatus that welds the bus bar 30 to the terminal 11 of the battery cell 10. The manufacturing apparatus 100 is equipped with a plurality of pressure pieces 110 lined up in the X direction, a rotor 120 that presses the pressure pieces 110 toward the bus bar 30, and a welder 130. The pressure pieces 110 are provided in a housing 101 so as to be movable in the Z direction of the coordinate system in the figure, but the support structure for the pressure pieces 110 is not shown. The housing 101 is also not shown in FIG. 3. The welder 130 is also supported by the housing 101, but the support structure for this is also not shown.

[0024] The multiple pressure pieces 110 are lined up in the X direction. The tip (lower end) of each pressure piece 110 faces the terminal 11 with the bus bar 30 in between. In other words, the terminal 11 is provided on the surface of the battery cell 10 facing the Z direction, and the tip of each pressure piece 110 faces the terminal 11 and is supported by the housing 101 (not shown in FIG. 3) so as to be movable in the Z direction. The pressure piece 110 is provided with a rack gear 112.

[0025] The rotor 120 includes a shaft 121, both ends of which are rotatably supported by the housing 101, and a plurality of pinion gears 122 engaged with the shaft 121. The shaft 121 is rotatably supported by the housing 101 via bearings 123. The shaft 121 is rotated about an axis line CL by a motor 124.

[0026] Each of the multiple pinion gears 122 is engaged with the rack gear 112 of the corresponding pressure piece 110. In other words, each of the multiple pinion gears 122 (contact pieces) is engaged with the rack gear 112 of the corresponding pressure piece 110. As shown in Fig. 3, when the shaft 121 rotates in the direction of the arrow line A, the pressure piece 110 is pressed in the direction of the arrow line B, and the pressure piece 110 presses the bus bar 30 against the terminal 11.

[0027] In the manufacturing apparatus 100, the welder 130 irradiates the welding laser LB toward the bus bar 30 while the bus bar 30 is pressed against the terminal 11. The bus bar 30 is welded to the terminal 11 by the welding laser LB.

[0028] 4, a plurality of pressure pieces 110 are arranged in the X direction, and each pressure piece 110 presses a bus bar 30 (not shown in FIG 4) against terminal 11. A welder 130 welds the plurality of bus bars 30 to terminal 11 in sequence.

[0029] 1, the terminals 11 of the battery cells 10 are arranged in two rows. After the bus bars 30 are welded to the multiple terminals 11 in one row, the stack of battery cells 10 and separators 20 is rotated 180 degrees around a vertical axis. Then, the multiple pressure pieces 110 press another bus bar 30 against the multiple terminals 11 in the other row, while a welder 130 welds the other bus bar 30 to the terminal 11.

[0030] The advantages of the manufacturing apparatus 100 will be described. Fig. 5 shows an explanatory diagram of forces acting on the rotor 120. The rotor 120, which presses the pressure piece 110 against the bus bar 30, receives a pressure reaction force Fr from the pressure piece 110. The rotor 120 receives the pressure reaction force Fr as forces F1 and F2. The force F1 is a force caused by the Z-direction bending rigidity Kz of the shaft 121 of the rotor 120, and the force F2 is a force caused by the torsional rigidity Ky of the shaft 121. If the Z-direction bending of the shaft 121 is represented by the symbol dZ and the torsional angle of the shaft 121 is represented by the symbol dY, the forces F1 and F2 are expressed by the equations shown in Fig. 5. As a result, the force (pressure reaction force Fr) that rotor 120 receives from pressure piece 110 is expressed by the formula Fr=F1+F2=Kz×dZ+Ky×dY×R (where symbol R is the distance from axis CL of shaft 121 to the point of application of pressure reaction force Fr).

[0031] Since a part of the pressure reaction force Fr is received by the torsional rigidity Ky of the shaft 121, the deflection dZ of the shaft 121 in the Z direction is reduced. In other words, the advantage is as follows. In the manufacturing apparatus 100, the shaft 121 supported at both ends presses the multiple bus bars 30 against the terminals 11 via the multiple pressure pieces 110. The shaft 121 receives a reaction force (pressure reaction force Fr) against the force pressing the bus bars 30. The pressure reaction force Fr is dispersed into a force F1 caused by the bending rigidity Kz of the shaft 121 and a force F2 caused by the torsional rigidity Ky. Since a part of the pressure reaction force Fr is converted into the torsional angle dY of the shaft 121, the deflection dZ of the shaft 121 in the Z direction is reduced.

[0032] Other features of the manufacturing apparatus 100 will be described. The engagement points between the multiple pinion gears 122 (contact pieces) and the shaft 121 are distributed around the shaft 121 when viewed from the X direction. This will be described with reference to Figures 4 and 6. As shown in Figure 4, the four pinion gears 122 from the bottom of the figure are denoted by the reference characters 122a, 122b, 122c, and 122d, respectively.

[0033] 6(1) to (4) show the engagement states of the pinion gears 122a, 122b, 122c, and 122d with the shaft 121, respectively. The shaft 121 and the pinion gear 122a are engaged with each other via a key 129a. Similarly, the shaft 121 and the pinion gear 122b (122c, 122d) are engaged with each other via a key 129b (129c, 129d). In FIG. 6, the keys 129a to 129d are hatched to facilitate understanding. The keys 129a to 129d correspond to the engagement points of the pinion gears 122a to 122d with the shaft 121, respectively.

[0034] The engagement point (key 129a) between the pinion gear 122a and the shaft 121 is located directly above the shaft 121. At this time, the force Fa caused by the torsional stiffness Ky of the pressure reaction force Fr faces the left direction in the figure as shown in FIG. 6(1). The engagement point (key 129b) between the pinion gear 122b and the shaft 121 is located on the left side of the shaft 121 (FIG. 6(2)). At this time, the force Fb caused by the torsional stiffness Ky of the pressure reaction force Fr faces downward in the figure as shown in FIG. 6(2). The engagement point (key 129c) between the pinion gear 122c and the shaft 121 is located on the lower side of the shaft 121 (FIG. 6(3)). At this time, the force Fc caused by the torsional stiffness Ky of the pressure reaction force Fr faces the right direction in the figure as shown in FIG. 6(3). The engagement point (key 129d) between the pinion gear 122d and the shaft 121 is located on the right side of the shaft 121 (FIG. 6(4)). At this time, of the pressure reaction force Fr, the force Fd caused by the torsional rigidity Ky faces upward in the drawing, as shown in FIG. 6(4).

[0035] In this way, when the engagement points (keys 129a to 129d) between the multiple pinion gears 122 (abutment pieces) and the shaft 121 are distributed around the shaft 121 when viewed from the X direction (stacking direction), the moment (force caused by the torsional rigidity Ky) acting on the shaft 121 is evenly applied around the shaft 121. Because the force (moment) is evenly applied to the shaft 121, the torsion of the shaft 121 is not biased.

[0036] The engagement points between the pinion gear 122 and the shaft 121 other than the pinion gears 122a to 122d are also distributed along the circumference of the shaft 122 when viewed in the X direction. It is sufficient that the engagement points between the multiple pinion gears 122 and the shaft 121 are distributed along the circumference of the shaft 121 when viewed in the X direction.

[0037] (Modification) Fig. 7 shows a side view of a modification of the manufacturing apparatus 200. In the manufacturing apparatus 100 of the embodiment, the pressure piece 110 is provided with a rack gear 112, and the rotor 120 is provided with a pinion gear 122. In the modification of Fig. 7, the rotor 220 is provided with a contact piece 222 having one protrusion 224. Also, the pressure piece 210 is a simple rod without a rack gear.

[0038] Abutment piece 222 engages with shaft 221 and has a protrusion 224 on its edge. Protrusion 224 contacts the upper end of pressure piece 210. As shown in FIG. 7 , when shaft 221 rotates in the direction of arrow C, pressure piece 210 is pressed in the direction of arrow D, and pressure piece 210 presses bus bar 30 against terminal 11.

[0039] Furthermore, shaft 221 and abutment piece 222 engage via torsion spring 223. To facilitate understanding, torsion spring 223 is hatched in Fig. 7. Torsion spring 223 has elasticity in the circumferential direction of shaft 221 (the rotational direction of shaft 221). Rotor 220 is provided with a plurality of abutment pieces 222 corresponding to a plurality of battery cells 10 in the assembled battery. There may be variation in the height of bus bars 30 corresponding to each terminal 11 of the plurality of battery cells 10. Even if the heights of the plurality of bus bars 30 vary, torsion spring 223 absorbs the variation and presses the plurality of bus bars 30 with approximately the same force.

[0040] In the embodiment, the shaft 121 of the rotor 120 and each of the abutment pieces (pinion gears 122) may be engaged via a torsion spring.

[0041] Points to note regarding the technology described in the examples are described below. The stack (a stack of multiple battery cells 10 and multiple separators 20) set in the manufacturing apparatus 100 is aligned in the X direction of the coordinate system in the figure. The manufacturing apparatus 100 is equipped with multiple pressure pieces 110 aligned in the X direction. Each pressure piece 110 is supported by a housing 101 of the apparatus so as to be swingable in the Z direction.

[0042] The manufacturing apparatus 100 includes a rotor 120. The rotor 120 extends along the X direction, and is rotated around an axis CL by a motor 124. The rotor 120 includes a shaft 121 and a plurality of pinion gears 122. When the rotor 120 rotates around the axis CL, the rotor 120 moves each of the plurality of pressure pieces 110 toward the corresponding bus bar 30. The moved pressure pieces 110 press the opposing bus bar 30, and press the bus bar 30 against the corresponding terminal 11.

[0043] The X direction in the figure corresponds to the first direction, and the Z direction corresponds to the second direction. The "assembled battery" may also be expressed as a "battery pack."

[0044] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful. [Explanation of symbols]

[0045] 2: Battery pack 10, 10a to 10c: Battery cell 11: Terminal 11n: Negative terminal 11p: Positive terminal 20: Separator 21: Partition plate 21a: Upper edge 22: Frame 23: Rib 24: Slit 25: Lip 30: Bus bar 31a, 31b: Arm portion 32: Bottom portion 40: End plate 100, 200: Manufacturing device 101: Housing 110, 210: Pressure piece 112: Rack gear 120, 220: Rotor 121, 221: Shaft 122, 122a to 122d: Pinion gear (contact piece) 123: Bearing 124: Motor 129a to 129d: Key 130: Welder 210: Pressure piece 222: Contact piece 223: Torsion spring 224: Protrusion

Claims

1. A battery pack manufacturing device, the assembled battery includes a plurality of battery cells stacked in a first direction, each battery cell including a terminal on a surface facing a second direction intersecting the first direction, and a bus bar welded to the terminal; The manufacturing apparatus includes: a plurality of pressure pieces arranged along the first direction, with tips in the second direction facing the respective terminals across the bus bar; a rotor extending along the first direction and rotated by an actuator, the rotor engaging with the plurality of pressure pieces and pushing the plurality of pressure pieces toward the bus bar when the rotor rotates about an axis; a welder that welds the bus bar and the terminal; It is equipped with The rotor presses the bus bar against the terminal, while the welding tool welds the bus bar to the terminal. Manufacturing equipment.

2. The rotor has a shaft that rotates with the actuator and a plurality of abutment pieces that engage with the shaft, Each of the plurality of abutment pieces abuts against a corresponding one of the pressure pieces. The manufacturing apparatus according to claim 1 .

3. The manufacturing apparatus according to claim 2 , wherein a plurality of engagement points between the abutment pieces and the shaft are distributed around the shaft when viewed from the first direction.

4. 3. The manufacturing apparatus according to claim 2, wherein a spring having elasticity in a circumferential direction of the shaft is interposed between the shaft and each of the abutment pieces.

5. The manufacturing apparatus according to claim 2 , wherein the contact piece is a pinion gear, and the pressure piece is provided with a rack gear that engages with the pinion gear.

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