Battery cell connection structure

Abstract

SOLUTION: There is provided a battery cell connection structure that connects two battery cells 14 in series with two rectangular battery cells 14 stacked in the thickness direction, in which a positive electrode tab 20a of one of the battery cells 14 and a negative electrode tab 20b of the other battery cell 14 are inclined with respect to the direction in which the two battery cells 14 are stacked, and with the positive electrode tab 20a and the negative electrode tab 20b stacked in the thickness direction, the positive electrode tab 20a and the negative electrode tab 20b are connected.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a connection structure of battery cells.

Background Art

[0002] The following Patent Document 1 discloses a connection structure of battery cells. In this connection structure of battery cells, an electrode of a battery cell and an electrode of another battery cell are fastened by a screw.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the thickness of the battery cell is relatively thin with respect to the screw, in the technique disclosed in the above Patent Document 1, there is a problem that a gap occurs between the battery cells.

[0005] An object of the present invention is to solve the above-described problems.

Means for Solving the Problems

[0006] An aspect of the present invention is a battery cell connection structure for connecting two rectangular battery cells in series with the two battery cells stacked in the thickness direction, wherein a positive electrode tab and a negative electrode tab are provided on the first side of each of the multiple sides of the battery cell, the two battery cells are stacked with their respective first sides facing the same direction, the positive electrode tab of one battery cell and the negative electrode tab of the other battery cell are connected with the two cells stacked in the thickness direction, and each of the positive electrode tab of one battery cell and the negative electrode tab of the other battery cell is bent so as to be inclined with respect to the direction in which the two battery cells are stacked and the direction connecting the first side of each battery cell and the second side opposite the first side, and the positive electrode tab and the negative electrode tab are connected with respect to the direction in which the two battery cells are stacked. [Effects of the Invention]

[0007] This invention makes it possible to shorten the distance between battery cells. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view of the battery module. [Figure 2] Figure 2 is a perspective view of a battery cell. [Figure 3] Figure 3 is a perspective view of the battery cell stack and heat exchanger. [Figure 4] Figure 4 is a perspective view of the first heat exchange plate and the second heat exchange plate. [Figure 5] Figure 5 is a cross-sectional perspective view of the battery cell stack and heat exchanger. [Figure 6] Figure 6 is a cross-sectional view of the battery cell stack and heat exchanger. [Figure 7] Figure 7 is a cross-sectional perspective view of the battery cell stack and heat exchanger. [Figure 8] Figure 8 is a perspective view of the battery cell stack. [Figure 9] Figure 9 is a perspective view of the battery cell stack. [Figure 10] Figure 10 is a cross-sectional view of a battery cell stack. [Figure 11] Figure 11 is a perspective view of the battery frame. [Figure 12] Figure 12 is a side view of the battery frame. [Figure 13] Figure 13 is a schematic diagram showing a comparative example of battery cell connection structures. [Figure 14] Figure 14 is a schematic diagram showing a comparative example of battery cell connection structures. [Figure 15] Figure 15 is a schematic diagram showing an example of a battery cell connection structure. [Modes for carrying out the invention]

[0009] [First Embodiment] [Battery module configuration] Figure 1 is a perspective view of the battery module 10. In the following description of the structure of each component constituting the battery module 10, the directions and orientations of the X, Y, and Z axes indicated by arrows in Figure 1 will be used. Arrows indicating the X, Y, and Z axes will also be drawn in the other figures described later. The directions and orientations of the X, Y, and Z axes indicated by arrows in the figures other than Figure 1 correspond to the directions and orientations of the X, Y, and Z axes indicated by arrows in Figure 1.

[0010] The battery module 10 has four battery cell stacks 12. The four battery cell stacks 12 are arranged in the Y-axis direction with the longitudinal direction of each battery cell stack 12 facing the X-axis direction. Each battery cell stack 12 has multiple battery cells 14. In each battery cell stack 12, the multiple battery cells 14 are stacked in the X-axis direction. That is, the stacking direction of the battery cells 14 is the same as the X-axis direction. Each battery cell 14 is stacked in its thickness direction. In each battery cell stack 12, each battery cell 14 is connected in series with another battery cell 14.

[0011] The battery module 10 has a heat exchanger 16. The heat exchanger 16 cools each battery cell 14.

[0012] The battery module 10 has four battery frames 18. Each battery frame 18 holds each battery cell stack 12. Each battery frame 18 applies pressure to the battery cell stack 12 from both sides in the X-axis direction. Thereby, the expansion of each battery cell 14 is suppressed.

[0013] [Configuration of Battery Cell] FIG. 2 is a perspective view of the battery cell 14. FIG. 2 shows a state where two battery cells 14 are overlapped.

[0014] The battery cell 14 is a laminated battery. The battery cell 14 is formed in a rectangular plate shape. The battery cell 14 is provided with a positive electrode tab 20a and a negative electrode tab 20b. The positive electrode tab 20a and the negative electrode tab 20b are provided on the first side 14a among a plurality of sides of the battery cell 14. The positive electrode tab 20a is formed in a rectangular plate shape. The negative electrode tab 20b is formed in a rectangular plate shape.

[0015] [Configuration of Heat Exchanger] FIG. 3 is a perspective view of the battery cell stack 12 and the heat exchanger 16. In FIG. 3, a part of the battery cell stack 12 and a part of the heat exchanger 16 are drawn. FIG. 4 is a perspective view of the first heat exchange plate 22 and the second heat exchange plate 24. FIG. 5 is a cross-sectional perspective view of the battery cell stack 12 and the heat exchanger 16. In FIG. 5, a part of the battery cell stack 12 and a part of the heat exchanger 16 are drawn. FIG. 6 is a cross-sectional view of the battery cell stack 12 and the heat exchanger 16. In FIG. 6, a part of the battery cell stack 12 and a part of the heat exchanger 16 are drawn.

[0016] The heat exchanger 16 has a plurality of first heat exchange plates 22 and a plurality of second heat exchange plates 24. The plurality of first heat exchange plates 22 and the plurality of second heat exchange plates 24 are stacked side by side in the X-axis direction. The plurality of first heat exchange plates 22 and the plurality of second heat exchange plates 24 are stacked in the thickness direction of the first heat exchange plates 22 and the thickness direction of the second heat exchange plates 24. The plurality of first heat exchange plates 22 and the plurality of second heat exchange plates 24 are stacked alternately.

[0017] The structure of the second heat exchange plate 24 is the same as that of the first heat exchange plate 22. In the heat exchanger 16, the orientation in which the first heat exchange plate 22 is positioned is different from the orientation in which the second heat exchange plate 24 is positioned.

[0018] The first heat exchange plate 22 has a first water jacket 26. The longitudinal direction of the first water jacket 26 extends in the Y-axis direction. The first water jacket 26 has a first supply passage 28 and a first return passage 30. In the Z-axis direction, the first supply passage 28 is located on the positive Z-axis side with respect to the center of the first water jacket 26. In the Z-axis direction, the first return passage 30 is located on the negative Z-axis side with respect to the center of the first water jacket 26. Cooling water flows inside the first supply passage 28. The cooling water flows in the first supply passage 28 from the negative Y-axis side to the positive Y-axis side. Cooling water flows inside the first return passage 30. The cooling water flows in the first return passage 30 from the positive Y-axis side to the negative Y-axis side. That is, the Y-axis direction is the same direction as the flow direction of the cooling water inside the first water jacket 26.

[0019] The first heat exchange plate 22 has a first water supply and drainage header 32. The first water supply and drainage header 32 is attached to the negative Y-axis end of the first water jacket 26. The first water supply and drainage header 32 has a first water inlet 34 that supplies cooling water to the first supply channel 28. The first water inlet 34 has a first water supply connector 36. The first water supply connector 36 is inserted into the first water inlet 34 of another first heat exchange plate 22 located on the positive X-axis side. The first water supply connector 36 has a seal groove 36a. A seal member 38 is attached to the seal groove 36a. The first water supply and drainage header 32 has a first drain port 40 that discharges cooling water from the first return channel 30. In the Y-axis direction, the first drain port 40 is located on the same side as the first water inlet 34 relative to the first water jacket 26. The first drain port 40 has a first drain connector 42. The first drainage connector 42 is inserted into the first drainage port 40 of another first heat exchange plate 22 located on the positive side in the X-axis direction. The first drainage connector 42 has a seal groove 42a. A seal member 44 is attached to the seal groove 42a.

[0020] The first heat exchange plate 22 has a first turn header 46. The first turn header 46 is attached to the positive Y-axis end of the first water jacket 26. As a result, the first turn header 46 is positioned on the opposite side of the first water inlet 34 and the first drain outlet 40 from the first water jacket 26. The first turn header 46 directs the cooling water flowing from the first supply channel 28 to the first return channel 30. The first turn header 46 is formed in a curved shape that protrudes outward from the first heat exchange plate 22 in the Y-axis direction. As a result, the first turn header 46 is able to smoothly change the direction of the cooling water flowing from the first supply channel 28 and direct it to the first return channel 30.

[0021] The second heat exchange plate 24 has a second water jacket 48. The longitudinal direction of the second water jacket 48 extends in the Y-axis direction. The second water jacket 48 has a second supply passage 50 and a second return passage 52. In the Z-axis direction, the second supply passage 50 is located on the positive Z-axis side with respect to the center of the second water jacket 48. In the Z-axis direction, the second return passage 52 is located on the negative Z-axis side with respect to the center of the second water jacket 48. Cooling water flows inside the second supply passage 50. The cooling water flows in the second supply passage 50 from the positive Y-axis side to the negative Y-axis side. Cooling water flows inside the second return passage 52. The cooling water flows in the second return passage 52 from the negative Y-axis side to the positive Y-axis side. That is, the Y-axis direction is the same direction as the flow direction of the cooling water inside the second water jacket 48.

[0022] The second heat exchange plate 24 has a second water supply and drain header 54. The second water supply and drain header 54 is attached to the positive Y-axis end of the second water jacket 48. The second water supply and drain header 54 has a second water inlet 56 that supplies cooling water to the second supply channel 50. In the Y-axis direction, the second water inlet 56 is located on the opposite side of the first water inlet 34 from the first water jacket 26 and the second water jacket 48. The second water inlet 56 has a second water supply connector 58. The second water supply connector 58 is inserted into the second water inlet 56 of another second heat exchange plate 24 located on the positive X-axis side. The second water supply connector 58 has a seal groove 58a. A seal member 60 is attached to the seal groove 58a. The second water supply and drain header 54 has a second drain port 62 that discharges cooling water from the second return channel 52. In the Y-axis direction, the second drain port 62 is located on the same side as the second water inlet 56 relative to the second water jacket 48. In the Y-axis direction, the second drain port 62 is located on the opposite side of the first drain port 40 relative to the first water jacket 26 and the second water jacket 48. The second drain port 62 has a second drain connector 64. The second drain connector 64 is inserted into the second drain port 62 of another second heat exchange plate 24 located on the positive side in the X-axis direction. The second drain connector 64 has a seal groove 64a. A seal member (not shown) is attached to the seal groove 64a.

[0023] The second heat exchange plate 24 has a second turn header 68. The second turn header 68 is attached to the negative Y-axis end of the second water jacket 48. As a result, the second turn header 68 is positioned on the opposite side of the second water jacket 48 from the second water inlet 56 and the second drain outlet 62. The second turn header 68 directs the cooling water flowing from the second supply channel 50 to the second return channel 52. The second turn header 68 is formed in a curved shape that protrudes outward from the second heat exchange plate 24 in the Y-axis direction. As a result, the second turn header 68 is able to smoothly change the direction of the cooling water flowing from the second supply channel 50 and direct it to the second return channel 52.

[0024] Figure 7 is a cross-sectional perspective view of the battery cell stack 12 and the heat exchanger 16. Figure 7 shows a portion of the battery cell stack 12 and a portion of the heat exchanger 16.

[0025] Two battery cells 14 are positioned between the first heat exchange plate 22 and the second heat exchange plate 24 in the X-axis direction. The two battery cells 14 are stacked in the thickness direction. The outer surfaces of the two stacked battery cells 14 are in direct contact with the first water jacket 26 of the first heat exchange plate 22 or the second water jacket 48 of the second heat exchange plate 24. Each battery cell 14 is positioned between the first heat exchange plate 22 and the second heat exchange plate 24 with its positive electrode tab 20a and negative electrode tab 20b facing the positive side in the Z-axis direction.

[0026] [Battery cell connection structure] Figure 8 is a perspective view of the battery cell stack 12. Figure 9 is a perspective view of the battery cell stack 12. Figure 10 is a cross-sectional view of the battery cell stack 12.

[0027] The positive electrode tab 20a of each battery cell 14 is connected to the negative electrode tab 20b of another adjacent battery cell 14 positioned on the positive side in the X-axis direction. The positive electrode tab 20a and the negative electrode tab 20b are stacked in the thickness direction. Each of the positive electrode tab 20a and the negative electrode tab 20b is bent so that it is tilted with respect to the X-axis direction. The X-axis direction is the same direction in which the battery cells 14 are stacked together. Each of the positive electrode tab 20a and the negative electrode tab 20b is bent so that it is tilted with respect to the Z-axis direction. The Z-axis direction is the same direction in which the first side 14a of each battery cell 14 is connected to the second side 14b (Figure 2) opposite to the first side 14a.

[0028] With the positive electrode tab 20a and the negative electrode tab 20b sandwiched between the tab holder 70 and the retaining plate 72, the tab holder 70 and the retaining plate 72 are fastened together with a screw 74.

[0029] [Battery frame configuration] Figure 11 is a perspective view of the battery frame 18. Figure 12 is a side view of the battery frame 18.

[0030] The battery frame 18 has a pair of flat spring plates 76, a pair of pressure plates 78, and four connecting shafts 80.

[0031] A pair of pressure plates 78 are provided between a pair of flat spring plates 76. A battery cell stack 12 is provided between the pair of pressure plates 78 (Figure 1). Each connecting shaft 80 extends in the X-axis direction. Each connecting shaft 80 connects the pair of flat spring plates 76.

[0032] Each flat spring plate 76 has a central portion 76a and four arm portions 76b. Each arm portion 76b extends from the central portion 76a. Each arm portion 76b extends diagonally outward from the battery frame 18 in the X-axis direction with respect to the Z-axis direction.

[0033] Each flat spring plate 76 has a first region and a second region. The first region is the area of ​​the tip portion of each arm portion 76b. The second region is the area other than the first region. The second region includes the central portion 76a. In the X-axis direction, the second region is located inside the battery frame 18 more than the first region.

[0034] Each pressure plate 78 is attached to the central portion 76a of each flat spring plate 76. Each pressure plate 78 may also be attached to the second region of the arm portion 76b of each flat spring plate 76. Each pressure plate 78 is attached to each flat spring plate 76 by screws 82. Each pressure plate 78 may also be attached to each flat spring plate 76 by welding.

[0035] In the Z-axis direction, the first region of the arm portion 76b of each flat spring plate 76 overlaps with each pressure plate 78. In the Y-axis direction, the first region of the arm portion 76b of each flat spring plate 76 overlaps with each pressure plate 78. The Z-axis and Y-axis directions are the same directions as those perpendicular to the stacking direction of the battery cell stack 12.

[0036] Each connecting shaft 80 is attached to the first region of the arm portion 76b of each flat spring plate 76. An adjustment bolt 84 is screwed onto each connecting shaft 80 outside of each flat spring plate 76. With the battery cell stack 12 positioned between the pair of pressure plates 78, tightening the adjustment bolt 84 increases the pressure applied to the battery cell stack 12 from the pair of pressure plates 78. By adjusting the tightening amount of the adjustment bolt 84, the pressure applied to the battery cell stack 12 is set to 200kPa to 400kPa.

[0037] [Effects and Effects] In the battery cell stack 12 of this embodiment, adjacent battery cells 14 in the X-axis direction are connected in series. The positive electrode tab 20a and the negative electrode tab 20b are overlapped in the thickness direction of the positive electrode tab 20a and the negative electrode tab 20b. In this state, the positive electrode tab 20a and the negative electrode tab 20b are fastened together by screws 74.

[0038] Figure 13 is a schematic diagram showing a comparative example of the connection structure of a battery cell 14. In the comparative example shown in Figure 13, the positive electrode tab 20a is bent at a right angle toward the negative electrode tab 20b of the adjacent battery cell 14. The negative electrode tab 20b is bent at a right angle toward the positive electrode tab 20a of the adjacent battery cell 14. With the positive electrode tab 20a and the negative electrode tab 20b overlapping in the Z-axis direction, the positive electrode tab 20a and the negative electrode tab 20b are fastened together by a screw 74.

[0039] The thickness of the laminated battery cell 14 is relatively thin compared to the width of the screw head 74. Therefore, in the example of the battery cell connection structure shown in Figure 13, a gap is created between the battery cells 14.

[0040] Figure 14 is a schematic diagram showing a comparative example of the connection structure of the battery cell 14. In the comparative example shown in Figure 14, the positive electrode tab 20a and the negative electrode tab 20b are stacked in the X-axis direction, and the positive electrode tab 20a and the negative electrode tab 20b are fastened together with a screw 74. This allows the battery cell 14 to come into contact with the other battery cell 14.

[0041] In the battery cell stack 12, the battery cells 14 are stacked in the X-axis direction. In the example shown in Figure 14, when fastening the positive electrode tab 20a and the negative electrode tab 20b with a screw 74, the tool used to fasten the screw 74 interferes with another set of positive electrode tabs 20a and negative electrode tabs 20b.

[0042] Figure 15 is a schematic diagram showing the connection structure of the battery cell 14 in this embodiment. In the connection structure of this embodiment, the positive electrode tab 20a and the negative electrode tab 20b are each bent and tilted with respect to the X-axis direction. In addition, the positive electrode tab 20a and the negative electrode tab 20b are each bent and tilted with respect to the Z-axis direction. In this state, the positive electrode tab 20a and the negative electrode tab 20b are fastened together with a screw 74. Therefore, when fastening the positive electrode tab 20a and the negative electrode tab 20b with the screw 74, the tool does not interfere with another set of positive electrode tabs 20a and negative electrode tabs 20b.

[0043] In the battery cell 14 connection structure of this embodiment, the positive electrode tab 20a and the negative electrode tab 20b are sandwiched between the tab holder 70 and the retaining plate 72, and the tab holder 70 and the retaining plate 72 are fastened together with a screw 74. This ensures that the positive electrode tab 20a and the negative electrode tab 20b are in reliable contact.

[0044] Furthermore, the present invention is not limited to the embodiments described above, and various configurations can be taken without departing from the spirit of the invention.

[0045] [Invention obtained from the embodiment] The inventions that can be understood from the above embodiments are described below.

[0046] A battery cell connection structure in which two rectangular battery cells (14) are stacked in the thickness direction and two of the battery cells are connected in series, wherein a positive electrode tab (20a) and a negative electrode tab (20b) are provided on the first side (14a) of the multiple sides of each battery cell, the two battery cells are stacked with their respective first sides facing the same direction, the positive electrode tab of one battery cell and the negative electrode tab of the other battery cell are connected in a state where they are stacked in the thickness direction, and each of the positive electrode tab of one battery cell and the negative electrode tab of the other battery cell are bent so as to be inclined with respect to the direction in which the two battery cells are stacked and the direction connecting the first side of each battery cell and the second side (14b) opposite to the first side, and the positive electrode tab and the negative electrode tab are connected in a state where they are stacked in the thickness direction. By connecting the positive electrode tab of one battery cell to the negative electrode tab of another battery cell, the distance between the battery cells can be shortened.

[0047] In the battery cell connection structure described above, each of the battery cells may be a laminated type battery. The distance between battery cells can be shortened when the positive electrode tab of one battery cell is connected to the negative electrode tab of another battery cell.

[0048] In the battery cell connection structure described above, the positive electrode tab of one battery cell and the negative electrode tab of the other battery cell are sandwiched between the holder (70) and the plate (72), and the plate and the holder may be fastened together with a screw (74). This ensures that the positive electrode tab and the negative electrode tab are in reliable contact. [Explanation of Symbols]

[0049] 14...Battery cell 14a...First side 14b...Second side 20a...Positive electrode tab 20b... Negative electrode tab 70... Tab holder (holder) 72...Retaining plate (plate) 74...Screw

Claims

1. A battery cell connection structure in which two rectangular battery cells are stacked in the thickness direction and the two battery cells are connected in series, A positive electrode tab and a negative electrode tab are provided on the first of the multiple sides of each of the aforementioned battery cells. The positive electrode tab of one battery cell and the negative electrode tab of the other battery cell are connected in a state where they are overlapping in the thickness direction. With the two battery cells stacked with their respective first edges facing the same direction, the positive electrode tab of one battery cell and the negative electrode tab of the other battery cell are tilted in the same direction with respect to the first direction, which is the stacking direction in which the two battery cells are stacked, and the second direction, which connects the first edge of each battery cell to the second edge opposite the first edge. A battery cell connection structure in which the overlapping portion where the positive electrode tab of one battery cell and the negative electrode tab of the other battery cell overlap extends away from the first side of each of the two battery cells in the stacking direction.

2. In the battery cell connection structure described in claim 1, Each of the aforementioned battery cells is a laminate-type battery, and the battery cell connection structure.

3. In the battery cell connection structure according to claim 1 or 2, A battery cell connection structure in which the positive electrode tab of one battery cell and the negative electrode tab of the other battery cell are sandwiched between a holder and a plate, and the plate and the holder are fastened together with screws.

4. In the battery cell connection structure described in Claim 3, The holder is a battery cell connection structure formed such that it extends in the same direction as the angle at which the positive electrode tab of one battery cell and the negative electrode tab of the other battery cell are bent.

5. In the battery cell connection structure described in Claim 3, The screw fastening portion is located spaced apart in the stacking direction from each of the first sides of the two stacked battery cells, in a battery cell connection structure.

6. In the battery cell connection structure described in Claim 5, Two other battery cells are arranged adjacent to the two aforementioned battery cells, connected in series. A battery cell connection structure wherein the fastening portion of the screw overlaps with the other two battery cells in the stacking direction.

7. In the battery cell connection structure described in Claim 5, A battery cell connection structure wherein, when viewed from the axial direction of the screw, the head of the screw is positioned so as not to overlap with the holders of the other two battery cells.

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