Support structure of bus bar

Abstract

To provide a support structure of a bus bar, which can preferably and smoothly weld an electrode terminal and a bus bar of a battery cell.SOLUTION: A support structure of a bus bar comprises: a battery case 40 that holds a plurality of battery cells 11; a bus bar 20 that includes a pair of connection plates 21 that is arranged in parallel connected to a terminal 13 of the adjacent battery cell 11; and a bus bar case 50 that includes two frame-like housing parts S that house each connection plate 21, and is assembled to the battery case 40 in a state where each connection plate 21 is housed into the housing part S. The battery case 40 includes a first engagement part 42 and a second engagement part 46 that engage the bus bar case 50 on one end side and the other end side in a long direction of the bus bar 20 between the housing parts S, and the bus bar case 50 includes a first pressing part 71 and a second pressing part 75 that can press a side edge having different width directions of each bus bar 20 to the terminal 13 on the one end side and the other end side in the long direction of each connection plate 21.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a support structure for a bus bar. [Background technology]

[0002] Patent Document 1 discloses a power supply device including a plurality of battery cells each having positive and negative electrode terminals, and a bus bar that electrically connects opposing electrode terminals between adjacent battery cells among the plurality of battery cells. [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 the power supply device described in Patent Document 1, the electrode terminals of the battery cells are connected to the busbar by welding, but in order to ensure the welding strength between the electrode terminals and the busbar, the busbar needs to be positioned with no gaps between them and the electrode terminals before welding. For this reason, as shown in Fig. 10, the busbar 1 must be pressed with the jig jaws 2 of a mask jig, and laser light L must be irradiated to weld the busbar 1 and the electrode terminals 3 with no gaps between them, which is time-consuming. In addition, if the positional misalignment between the battery cells of the battery pack does not meet the tolerance standards, it is not possible to ensure space for inserting the jig jaws 2, making it difficult to weld smoothly.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a bus bar support structure that enables favorable and smooth welding of the electrode terminals of a battery cell and the bus bar. [Means for solving the problem]

[0006] In order to achieve the above object, the bus bar support structure of the present invention comprises: A battery case for holding a plurality of battery cells; a bus bar having a pair of connection plate portions arranged in parallel and connected to terminals of adjacent battery cells, respectively; a bus bar case including two frame-shaped accommodation portions each accommodating the connection plate portions of the bus bar, the bus bar case being assembled to the battery case with the connection plate portions accommodated in the accommodation portions; A bus bar support structure comprising: the battery case has locking portions that lock the bus bar case at one end side and the other end side in a longitudinal direction of the bus bar between the accommodation portions, The bus bar case has pressing portions at one and the other longitudinal ends of the connection plate portion accommodated in the accommodation portion, which are capable of pressing different widthwise side edges of the bus bar toward the terminals of the battery cells.

[0007] With this busbar support structure, the connecting plate portion of the busbar can be pressed against the terminal of the battery cell by the pressing portion. This allows the connecting plate portion of the busbar to abut against the terminal without any gaps, and allows for good and smooth welding and connection, without the need for a mask jig. In addition, the mask jig equipment is no longer necessary, reducing equipment costs and simplifying the manufacturing process, thereby reducing manufacturing costs. Furthermore, because the pressurized state between the terminal and busbar is maintained even after welding, vibration displacement that affects the fatigue life of the busbar can be suppressed. In addition, because no space is required to insert the jig claws, the tolerance standards for the amount of waviness when the battery cells are stacked can be relaxed, thereby reducing the occurrence of battery pack defects. Furthermore, the welding area of ​​the bus bar to the terminal can be expanded, which increases the current-carrying area at the connection point between the terminal and the bus bar and also extends the welding fatigue life. Effect of the Invention

[0008] The present invention provides a bus bar support structure that enables favorable and smooth welding of the electrode terminals of the battery cells and the bus bar. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a portion of a battery pack to which a bus bar support structure according to this embodiment is applied. [Diagram 2] FIG. 2 is a plan view of a portion of a battery pack to which the bus bar support structure according to this embodiment is applied. [Diagram 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line BB in FIG. [Diagram 5] FIG. 5 is a perspective view of a bus bar. [Figure 6] FIG. 6 is a perspective view of the upper part of the battery case. [Figure 7] FIG. 7 is a plan view of the bus bar case. [Figure 8A] FIG. 8A is a cross-sectional view taken along the line AA in FIG. 2, illustrating a state in which the bus bar is pressed with the other terminal lowered inward. [Figure 8B] FIG. 8B is a cross-sectional view taken along the line AA in FIG. 2, illustrating a state in which the bus bar is pressed with the other terminal lowered inward. [Figure 8C] FIG. 8C is a cross-sectional view taken along the line AA in FIG. 2, illustrating a state in which the bus bar is pressed with the other terminal lowered inward. [Figure 9A] FIG. 9A is a cross-sectional view taken along the line AA in FIG. 2, illustrating a state in which the bus bar is pressed with the other terminal lowered outward. [Figure 9B] FIG. 9B is a cross-sectional view taken along the line AA in FIG. 2, illustrating a state in which the bus bar is pressed with the other terminal lowered outward. [Figure 9C] FIG. 9C is a cross-sectional view taken along the line AA in FIG. 2, illustrating a state in which the bus bar is pressed with the other terminal lowered outward. [Figure 10] FIG. 10 is a diagram illustrating a problem that occurs when connecting the electrode terminals of the battery cells and the bus bars by welding. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a perspective view of a portion of a battery pack 12 to which the support structure for a bus bar 20 according to the present embodiment is applied. Fig. 2 is a plan view of a portion of a battery pack 12 to which the support structure for a bus bar 20 according to the present embodiment is applied. Fig. 3 is a cross-sectional view taken along line AA in Fig. 2. Fig. 4 is a cross-sectional view taken along line BB in Fig. 2.

[0011] 1 to 4, the busbar support structure according to this embodiment is applied to a battery pack 12 including a plurality of battery cells 11. The battery pack 12 is used in, for example, a power supply device for an electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, or the like.

[0012] Each battery cell 11 has two terminals 13, a positive electrode and a negative electrode. The battery cells 11 are stacked in such a way that the terminals 13 of different electrodes are adjacent to each other. The terminals 13 of adjacent battery cells 11 are electrically connected by a bus bar 20.

[0013] FIG. 5 is a perspective view of the bus bar 20. 5, busbar 20 is formed from a conductive plate made of a conductive metal material, and has two connection plate portions 21 and a linking plate portion 22. Busbar 20 is formed by subjecting the conductive plate to, for example, press working.

[0014] The connecting plate portions 21 are arranged in parallel with one another at intervals. The connecting plate portion 21 has a rising portion 23 that is bent upward and raised at the end portion on the connecting plate portion 22 side. The connecting plate portion 22 is connected to the end portion of the rising portion 23 of the connecting plate portion 21, and is bent laterally relative to the rising portion 23. The connecting plate portion 22 has a bent portion 22a that is bent downward in a U-shape at its intermediate portion.

[0015] The busbar 20 has its connection plate portion 21 welded and connected to the terminals 13 of the battery cells 11, for example, by laser welding. This electrically connects the positive and negative terminals 13 of adjacent battery cells 11 by the busbar 20, connecting the multiple battery cells 11 in series. The connection plate portion 21 has a connection portion 24 in which a hole 24a is formed, and this connection portion 24 is welded and connected to the terminal 13 of the battery cell 11.

[0016] The battery pack 12, which includes a plurality of battery cells 11 connected in series by bus bars 20, includes a battery case 40 and a bus bar case 50. The battery case 40 and the bus bar case 50 are each molded from an insulating synthetic resin.

[0017] The battery case 40 is a case that holds multiple battery cells 11 in a stacked state, and includes plate-shaped separator portions 41 that are disposed between adjacent battery cells 11.

[0018] FIG. 6 is a perspective view of the upper part of the battery case 40. As shown in FIG. As shown in FIG. 6, the separator portion 41 of the battery case 40 has a first locking portion 42 and a second locking portion 46 on its upper edge. The first locking portion 42 and the second locking portion 46 are provided at positions spaced apart from each other along the extension direction of the separator portion 41. The first locking portion 42 has a wall portion 43. The wall portion 43 is erected so as to be perpendicular to the extension direction of the separator portion 41. The wall portion 43 has a claw portion 43a formed on the surface opposite to the second locking portion 46. The second locking portion 46 has two locking projections 47, 48. The locking projections 47, 48 have claw portions 47a, 48a protruding in opposite directions.

[0019] FIG. 7 is a plan view of the bus bar case 50. As shown in FIG. 7, the busbar case 50 is formed in a rectangular frame shape having a front wall 51, a rear wall 52, and a pair of side walls 53. The busbar case 50 has a partition wall 54 provided between the side walls 53 and spanning the front wall 51 and the rear wall 52. The inside of the busbar case 50 is divided by the partition wall 54 into two accommodation sections S, and the connection plate sections 21 of the busbars 20 are accommodated in these accommodation sections S.

[0020] The rear wall 52 of the busbar case 50 has a mounting portion 55 extending horizontally rearward from its upper edge, and the connecting plate portion 22 of the busbar 20 is mounted on this mounting portion 55. This mounting portion 55 has a recess 56 that is recessed downward, and this recess 56 accommodates the bent portion 22a of the connecting plate portion 22 mounted on the mounting portion 55. An engagement hole 61 is formed in a bottom portion 56a of this recess 56.

[0021] The front wall 51 of the bus bar case 50 has an engagement piece 62 that protrudes forward on the front side thereof. Both ends of this engagement piece 62 are connected to the front wall 51 with a gap therebetween.

[0022] The busbar case 50 has a first pressing portion 71 and a second pressing portion 75 in each of the accommodation portions S. The first pressing portion 71 is provided on the tip side of the connection plate portion 21 of the busbar 20 accommodated in the accommodation portion S. The first pressing portion 71 is composed of pressing pieces 72 formed on each of the side walls 53. These pressing pieces 72 each protrude laterally toward the accommodation portion S. The second pressing portion 75 is provided on the rear end side of the connection plate portion 21 of the busbar 20 accommodated in the accommodation portion S. The second pressing portion 75 is composed of pressing pieces 76 formed on the partition portion 54. The upper end portions of the pressing pieces 76 are connected to the upper end of the partition portion 54 by a connecting portion 77, and each extends downward.

[0023] When the busbar 20 is held in the busbar case 50, the connection plate portions 21 of the busbar 20 are housed in their respective housing portions S, and the linking plate portions 22 are placed on the mounting portions 55 of the rear wall portion 52. When the busbar 20 is housed in this state, the pressing piece 72 of the first pressing portion 71 of the busbar case 50 is disposed with almost no gap on the upper surface side of the tip of the connection plate portion 21 of the busbar 20. Also, when the busbar 20 is housed in this state, the pressing piece 76 of the second pressing portion 75 of the busbar case 50 is disposed with almost no gap on the upper surface side of the rear end of the connection plate portion 21 of the busbar 20.

[0024] The busbar case 50 housing the busbars 20 is assembled from above to the battery cells 11 held by the battery case 40. When the busbar case 50 is assembled in this manner, the first locking portion 42 of the separate portion 41 of the battery case 40 is inserted between the front wall portion 51 and the engagement piece 62 of the busbar case 50. This causes the claw portion 43a of the first locking portion 42 to lock the engagement piece 62. Also, the second locking portion 46 of the separate portion 41 of the battery case 40 is inserted into the engagement hole 61 formed in the mounting portion 55 of the busbar case 50. This causes the claw portions 47a, 48a of the locking projections 47, 48 of the second locking portion 46 to lock the edge of the engagement hole 61.

[0025] In this way, the bus bar case 50 is fixed to the battery case 40 by the first locking portion 42 and the second locking portion 46 of the battery case 40. When the bus bar case 50 is fixed to the battery case 40, the connection plate portion 21 of the bus bar 20 housed in the bus bar case 50 abuts against the terminal 13 of the battery cell 11. In this state, the connection portion 24 of the connection plate portion 21 is welded to the terminal 13 by laser welding, whereby the terminals 13 of adjacent battery cells 11 are electrically connected to each other by the bus bar 20.

[0026] Incidentally, in a battery pack 12 in which multiple battery cells 11 are stacked, undulations may occur in the arrangement of the battery cells 11 due to the dimensional tolerances of the battery cells 11, the battery case 40, the bus bar case 50, etc., and the assembly method. When undulations occur in the arrangement of the battery cells 11, there is a risk that misalignment or inclination in the height direction may occur between the terminals 13 of adjacent battery cells 11. This may result in a gap between the connection plate portion 21 of the bus bar 20 and the terminal 13, making it difficult to perform smooth welding.

[0027] In contrast, according to the busbar support structure of this embodiment, when the busbar case 50 is assembled to the battery case 40, the first pressing portion 71 and the second pressing portion 75 press the connection plate portion 21 of the busbar 20 against the terminal 13 of the battery cell 11, so that they are in contact with each other without any gaps.

[0028] Next, the pressing of the connection plate portions 21 of the bus bars 20 against the terminals 13 when assembling the bus bar case 50 to the battery case 40 will be described.

[0029] 8A to 8C are cross-sectional views taken along the line AA in FIG. 2, each of which illustrates a state in which bus bar 20 is pressed with other terminal 13 lowered inward. As shown in FIG. 8A, if the height of the terminal 13 on one battery cell 11 (on the right side in the figure) is lower than the terminal 13 on the other battery cell 11 (on the right side in the figure) and the terminal 13 is tilted inward, when one connection plate portion 21 abuts against one terminal 13, a gap G that widens toward the inside is created between the other connection plate portion 21 and the other terminal 13.

[0030] In this state, when the busbar case 50 is pressed against the battery case 40, the other connection plate portion 21 is pressed downward by the first pressing portion 71 and the second pressing portion 75, as shown in Figure 8B, so that the connection plate portion 21 abuts against the outside of the terminal 13, and the gap G is only on the inside between the terminal 13 and the connection plate portion 21.

[0031] 8C , the inside of the other connection plate portion 21 is pressed downward by the second pressing portion 75, tilting the connection plate portion 21 inward and bringing the entire connection plate portion 21 into contact with the terminal 13 without any gaps. At this time, the first pressing portion 71 pressing the outside of the other connection plate portion 21 elastically deforms while pressing the connection plate portion 21, and absorbs the reaction force from the connection plate portion 21.

[0032] 9A to 9C are cross-sectional views taken along the line AA in FIG. 2, each of which illustrates a state in which bus bar 20 is pressed with other terminal 13 lowered outward. As shown in Figure 9A, if the height of the terminal 13 on one battery cell 11 (on the right side in the figure) is lower than the terminal 13 on the other battery cell 11 (on the left side in the figure) and the terminal 13 is tilted outward, when one connection plate portion 21 abuts against one terminal 13, a gap G that widens toward the outside is created between the other connection plate portion 21 and the other terminal 13.

[0033] 9B, the other connection plate portion 21 is pressed downward by the first pressing portion 71 and the second pressing portion 75 so that the connection plate portion 21 comes into contact with the entire upper surface of the terminal 13 without any gaps. Then, the entire busbar 20 together with the busbar case 50 is tilted in accordance with the inclination of the other terminal 13, and a gap G is generated between the outside of the one terminal 13 and the connection plate portion 21.

[0034] 9C , the outer side of one of the connection plates 21 is pressed downward by the first pressing portion 71, and the entire connection plate portion 21 is brought into contact with the terminal 13 without any gaps. The second pressing portion 75 pressing the inner side of the one of the connection plates 21 elastically deforms while pressing the connection plate portion 21, and absorbs the reaction force from the connection plate portion 21.

[0035] Any twisting or torsion of busbar 20 that occurs when connecting plate portion 21 is pressed against each terminal 13 so as to abut against each terminal 13 without any gaps is absorbed by the deformation of bent portion 22a of linking plate portion 22.

[0036] As described above, with the busbar support structure according to this embodiment, the connection plate portion 21 of the busbar 20 can be pressed against the terminal 13 of the battery cell 11 by the first pressing portion 71 and the second pressing portion 75. This allows the connection plate portion 21 of the busbar 20 to be brought into contact with the terminal 13 without any gaps and to be satisfactorily and smoothly welded and connected without using a mask jig. In addition, a mask jig is no longer necessary, reducing equipment costs and simplifying the manufacturing process, thereby reducing manufacturing costs. Furthermore, because the pressurized state between the terminal 13 and the busbar 20 is maintained even after welding, vibration displacement that affects the fatigue life of the busbar 20 can be suppressed.

[0037] Also, because no space is required to insert the jig claws, the tolerance standards for the amount of waviness when the battery cells 11 are stacked can be relaxed, thereby reducing the occurrence of defects in the battery pack 12. Moreover, the welding area of ​​the bus bar 20 to the terminal 13 can be expanded, which increases the current-carrying area at the connection point between the terminal 13 and the bus bar 20 and also extends the welding fatigue life.

[0038] It is preferable that the second pressing portion 75, which presses the base portion of the connection plate portion 21 of the busbar 20, has a higher rigidity than the first pressing portion 71, which presses the tip side of the connection plate portion 21. In this way, the connection plate portion 21 of the busbar 20 can be pressed against the terminals 13 of the battery cells 11 in a well-balanced manner. [Explanation of symbols]

[0039] 11 Battery Cell 13 Terminals 20 Busbar 21 Connection plate 40 Battery case 42 First locking portion (locking portion) 46 Second locking portion (locking portion) 50 Busbar case 71 First pressing part (pressing part) 75 Second pressing part (pressing part) S Storage section

Claims

[Claim 1] A battery case for holding a plurality of battery cells; a bus bar having a pair of connection plate portions arranged in parallel and connected to terminals of adjacent battery cells, respectively; a bus bar case including two frame-shaped accommodation portions each accommodating the connection plate portions of the bus bar, the bus bar case being assembled to the battery case with the connection plate portions accommodated in the accommodation portions; A bus bar support structure comprising: the battery case has locking portions that lock the bus bar case at one end side and the other end side in a longitudinal direction of the bus bar between the accommodation portions, the bus bar case has pressing portions at one end side and the other end side in a longitudinal direction of the connection plate portion accommodated in the accommodation portion, the pressing portions being capable of pressing different side edges in a width direction of the bus bar toward the terminals of the battery cells. Busbar support structure.

Images