Battery module and battery case

Abstract

To solve a problem in which a conventional battery module is difficult to be disassembled.SOLUTION: A battery module 1 according to the present invention includes a plurality of battery cells 20 arranged side by side in a stacking direction, and a battery case 10 that houses the plurality of battery cells 20. The battery case 10 includes a plurality of through holes 11, 12 that penetrate the wall surfaces at positions corresponding to the plurality of battery cells 20 on two wall surfaces facing each other in a width direction perpendicular to the stacking direction, and the plurality of battery cells 20 each have cell fixing arms 21a, 22a that are electrically connected to electrodes and elastically support cell fixing protrusions 21b, 22b that fit into the corresponding through holes.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to, for example, a battery module and a battery case. [Background technology]

[0002] Many battery modules have been proposed in which a plurality of battery cells are stacked and housed in a battery case. An example of such a battery module is disclosed in Patent Document 1.

[0003] The battery module described in Patent Document 1 includes a battery cell stack in which a plurality of battery cells are stacked, and a plurality of bus bars each coupled to an electrode lead provided on each of the plurality of battery cells, the bus bar including a frame on which the electrode leads of the battery cells are attached, and a conductive member coupled to the frame and electrically coupled to the electrode leads. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2020-504427 Summary of the Invention [Problem to be solved by the invention]

[0005] In the battery module etc. described in Patent Document 1, the battery stack is stored in the battery case with a restraining load applied to the battery stack by a band or a battery case. Therefore, in the battery module etc. described in Patent Document 1, a reaction force from the battery cells etc. that are subject to the restraining load must be countered during disassembly, making disassembly difficult.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to improve the ease of disassembling a battery module. [Means for solving the problem]

[0007] One aspect of a battery module according to the present invention comprises a plurality of battery cells arranged in a stacking direction, and a battery case that houses the plurality of battery cells, wherein the battery case has a plurality of through holes penetrating two opposing wall surfaces in a width direction perpendicular to the stacking direction, at positions corresponding to the plurality of battery cells, and each of the plurality of battery cells has a cell fixing arm that is electrically connected to an electrode and elastically supports a cell fixing protrusion that fits into the corresponding through hole.

[0008] One aspect of a battery case according to the present invention is a battery case that houses a plurality of battery cells arranged side by side in a stacking direction, and has a plurality of through holes penetrating two wall surfaces opposing each other in a width direction perpendicular to the stacking direction, at positions corresponding to the plurality of battery cells, and a sealing member that is electrically conductive and that is arranged to surround the periphery of the through hole on the inner side of the battery case and elastically deforms due to a pushing force by a cell fixing protrusion that is elastically supported by a cell fixing arm that is electrically connected to an electrode of each of the plurality of battery cells is provided, and a conductive layer that is conductive is provided on the inner wall of the through hole, and the sealing member is molded so as to contact the conductive layer when pressed by the cell fixing protrusions. Effect of the Invention

[0009] According to the battery module and the battery case of the present invention, the ease of disassembling the battery module can be improved. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a battery module according to a first embodiment. [Diagram 2] 2A to 2C are diagrams illustrating the structure of the battery module according to the first embodiment and a first assembly step. [Diagram 3] 4A to 4C are diagrams illustrating the structure of the battery module according to the first embodiment and a second assembly process. [Figure 4] 1A to 1C are diagrams illustrating the structure and dismantling process of a battery module according to a first embodiment. [Diagram 5] FIG. 4 is a diagram for explaining an assembly inspection of the battery module according to the first embodiment. [Figure 6] 4 is a flowchart illustrating a flow of assembly inspection for the battery module according to the first embodiment. [Figure 7] FIG. 11 is a schematic diagram of a battery module according to a second embodiment. [Figure 8] 13A and 13B are diagrams illustrating the structure of a through hole provided in a battery module according to a second embodiment. [Figure 9] FIG. 11 is a diagram illustrating a battery module according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In order to clarify the explanation, the following description and drawings are omitted and simplified as appropriate. In each drawing, the same elements are given the same reference numerals, and repeated explanations are omitted as necessary. In the following explanation, the direction in which the longest side of the battery cell extends is defined as the horizontal direction X or width direction X, the direction in which the battery cells are arranged is defined as the stacking direction Y, and the direction perpendicular to the horizontal direction X and the stacking direction Y, which is the height of the stack case or the height of the battery cell, is defined as the height direction Y or vertical direction Y. The stacking direction Y also coincides with the direction in which the shortest side of the battery cell extends. In the following explanation, the horizontal direction X may be referred to as the left-right direction, and the vertical direction Y may be referred to as the up-down direction.

[0012] First embodiment FIG. 1 shows a schematic diagram of a battery module 1 according to the first embodiment. As shown in FIG. 1, in the battery module 1 according to the first embodiment, a plurality of battery cells 20 are housed in a battery case 10 so as to be arranged along a stacking direction Y. Here, in the battery case 10, the plurality of battery cells 20 are housed in the battery case 10 in an unconstrained state. In the battery module 1 according to the first embodiment, the battery cells 20 are arranged in the battery case 10 so that the positive electrodes and the negative electrodes of adjacent battery cells 20 are arranged alternately. In the battery cell 20 according to the first embodiment, an electrode terminal connected to the positive electrode of the adjacent battery cell and an electrode terminal of the negative electrode are connected by a bus bar 23. As a result, the battery module 1 functions as a battery pack in which a plurality of battery cells are connected in series.

[0013] Further, electrode terminals 21, 22 are attached to the positive and negative electrodes of the multiple battery cells 20, respectively. In Fig. 1, the electrode terminal arranged on the right side in the stacking direction Y is denoted by reference numeral 21, and the electrode terminal arranged on the left side is denoted by reference numeral 22, but the reference numerals are used for convenience, and do not indicate that the electrode terminals 21, 22 are either positive or negative. As will be described in more detail later, in the battery module 1, each battery cell is fixed in the battery case 10 using a cell fixing arm and a cell fixing protrusion provided on the electrode terminals 21, 22.

[0014] The battery case 10 according to the first embodiment has a plurality of through holes 11 penetrating the two opposing wall surfaces in the width direction X perpendicular to the stacking direction Y at positions corresponding to the plurality of battery cells 20. In FIG. 1, a through hole 12 is formed in the wall surface opposite to the wall surface in which the through hole 11 is formed. The above-mentioned cell fixing protrusions are fitted into the through holes 11 and 12. The battery module 1 according to the first embodiment fixes the battery cells 20 by fitting the cell fixing protrusions into the through holes 11 and 12, and the battery cells 20 are removed from the battery case 10 by pushing a push pin into the through hole 11 to remove the cell fixing protrusion from the through hole 11. The structures of the cell fixing protrusions and the through holes in the battery module 1 according to the first embodiment will be described in detail below.

[0015] 2 shows a diagram for explaining the structure of the battery module 1 according to the first embodiment and a first assembly step. The first assembly step is a step of inserting the battery cells 20 into the battery case 10. Also, FIG. 2 is a cross-sectional view of a surface including the through holes 11 and 12 of the battery case 10.

[0016] 2 also shows structures associated with the through holes 11 and 12 provided in the battery case 10. Note that since the structure on the through hole 11 side and the structure on the through hole 12 side are the same, the structure associated with the through hole will be described here using the through hole 11 as an example.

[0017] As shown in FIG. 2, the through hole 11 is formed to penetrate the side wall of the battery case 10. A seal member 11c is provided on the inner side of the through hole 11 in the battery case 10 so as to surround the periphery of the through hole 11. The seal member 11c is elastically deformed due to a pressing force by the cell fixing protrusion 21b. The seal member 11c is made of a resin having electrical conductivity. A conductive layer 11b having electrical conductivity is provided on the inner peripheral wall of the through hole 11. In the example shown in FIG. 2, it is preferable to provide the seal member 11c so that the conductive layer 11b and the seal member 11c do not come into contact with each other before the battery cell 20 is stored in the battery case 10.

[0018] 2 shows an example in which the battery case 10 is formed from a conductive metal, and an insulating layer 11a is provided around the conductive layer 11b and the sealing member 11c to ensure insulation between the conductive layer 11b and the sealing member 11c and the battery case 10. When the battery case 10 is formed from an insulating resin or the like, the insulating layer 11a is not necessary.

[0019] FIG. 2 also shows the side shapes of the electrode terminals 21 and 22 attached to the battery cell 20. Since the electrode terminals 21 and 22 have the same structure, the structure of the electrode terminal will be described below using the electrode terminal 21 as an example. In the example shown in FIG. 2, the electrode terminal 21 has an L-shape along the upper surface and side surface of the battery cell 20. A cell fixing arm 21a is provided to protrude from a portion of the electrode terminal 21 that extends in the height direction, and a cell fixing arm 22a is provided at the tip of the cell fixing arm 21a. The electrode terminal 21 is electrically connected to the electrode of the battery cell, and the cell fixing arm 21a elastically supports the cell fixing protrusion 21b. More specifically, the cell fixing arm 21a elastically supports the cell fixing protrusion 21b so that the cell fixing protrusion 21b can be displaced in a direction to bring the cell fixing protrusion 21b closer to the battery cell 20 side and in a direction to press the cell fixing protrusion 21b against the through-hole 11 side.

[0020] Next, a diagram for explaining the structure of the battery module according to the first embodiment and a second assembly process is shown in Fig. 3. The second assembly process is a process for fitting the battery cells 20 into the battery case 10, and Fig. 3 shows the state after the battery cells 20 are fitted into the battery case 10.

[0021] As shown in FIG. 3, in the battery module 1, when the battery cell 20 is fitted into the battery case 10, the cell fixing arm 21a applies a pressing force to the cell fixing protrusion 21b so that the cell fixing protrusion 21b closes the through hole 11. At this time, the seal member 11c deforms so that the seal member 11c covers the inner surface of the conductive layer 11b of the battery case 10. This allows the voltage of the electrode terminal 21 to be transmitted to the conductive layer 11b. In addition, when the seal member 11c deforms to match the shape of the cell fixing protrusion 21b and the conductive layer 11b and the seal member 11c are in close contact with each other, the inside of the battery case 10 is sealed. In reality, the sealed state is established with a cover placed on the top surface of the battery case 10.

[0022] Next, a method for dismantling the battery module 1 according to the first embodiment will be described. FIG. 4 shows a diagram for explaining the structure and dismantling process of the battery module 1 according to the first embodiment. As shown in FIG. 4, in the battery module 1 according to the first embodiment, a push pin 31 is inserted into the through hole 11, and the cell fixing protrusion 21b is pushed in by the push pin 31, so that the cell fixing protrusion 21b is separated from the through hole 11. Also, a push pin 32 is inserted into the through hole 12 on the through hole 12 side, and the cell fixing protrusion 22b is pushed in by the push pin 32, so that the cell fixing protrusion 22b is separated from the through hole 11. This releases the fixation of the battery cell 20, so that the battery cell 20 can be easily removed from the battery case 10. The push pins 31 and 32 are inserted into the through holes 11 and 12 by a pressure device (not shown).

[0023] Next, in the battery module 1 according to the first embodiment, it is possible to check the airtightness after the battery cells 20 are assembled into the battery case 10 by devising a structure for the conductive layer 11b. Here, an inspection device for checking the airtightness and the structure of the conductive layer 11b in the battery module 1 will be described. Fig. 5 shows a diagram for explaining the assembly inspection for the battery module according to the first embodiment.

[0024] As shown in Fig. 5, in the battery case 10 according to the first embodiment, the conductive layers 11b, 12b are formed in a structure having a plurality of conductive wires embedded in an insulating member. In Fig. 5, the plurality of conductive wires exposed to the outside of the battery case 10 are called check terminals and are given the symbols RE1 to RE8 and LE1 to LE8. The plurality of check terminals are all provided so that their ends are exposed.

[0025] In the battery module 1 according to the first embodiment, with the battery cell 20 inserted in the battery case 10, the potential difference between the multiple check terminals on the through hole 11 side and the multiple check terminals on the through hole 12 side is measured. At this time, in the airtightness inspection of the battery module 1 according to the first embodiment, all voltage differences between one of the check terminals on one side and the check terminal on the other side are measured. In order to perform such measurements, switches SWR, SWL and a measurement circuit 40 are shown in FIG. 5 as an inspection device.

[0026] The switch SWR has a first terminal connected to the measurement circuit 40 and a plurality of second terminals corresponding to the plurality of check terminals. The switch SWL has a first terminal connected to the measurement circuit 40 and a plurality of second terminals corresponding to the plurality of check terminals. In the example shown in FIG. 5, eight check terminals are set on one side, so eight second terminals are also provided. The switches SWR and SWL select the second terminal according to an instruction from the measurement circuit 40. In addition to controlling the switches SWR and SWL, the measurement circuit 40 measures the voltage difference between the check terminals selected by the switches SWR and SWL, and judges the quality of the assembly based on the measured voltage difference.

[0027] FIG. 6 shows a flow chart for explaining the flow of the assembly inspection for the battery module 1 according to the first embodiment. As shown in FIG. 6, in the assembly inspection for the battery module 1 according to the first embodiment, a first inspection process is executed in which one of the multiple check terminals arranged on one of the left and right sides of the battery case 10 is used as a reference voltage and all voltages of the multiple check terminals arranged on the other side are acquired. In addition, in the assembly inspection for the battery module 1 according to the first embodiment, a second inspection process is executed in which one of the multiple check terminals arranged on the other side of the left and right sides of the battery case 10 is used as a reference voltage and all voltages of the multiple check terminals arranged on one side are acquired. Then, if all voltages acquired in the first inspection process and the second inspection process are equal to or higher than the airtightness threshold voltage, the battery module 1 is determined to be a non-defective product. A specific example shown in FIG. 6 will be explained below.

[0028] In the example shown in Fig. 6, first, the switch SWL is operated to select the check terminal LE1 from the multiple check terminals arranged on the left side of the battery case 10 (step S1). Then, the switch SWR is operated to switch the selected check terminal between the check terminal LE1 and the check terminals RE1 to RE8 arranged on the right side of the battery case 10, and obtain the voltage differences VR1 to VR8 between the check terminals (step S2). Then, if all of the voltage differences VR1 to VR8 are equal to or greater than a preset airtightness threshold voltage, the processing from step S4 onwards is performed (step S3). On the other hand, if any one of the voltage differences VR1 to VR8 is less than the airtightness threshold voltage, the battery case 10 to be inspected is determined to be a defective assembly (steps S3 and S8).

[0029] Next, the switch SWR is operated to select the check terminal RE1 from the multiple check terminals arranged on the right side of the battery case 10 (step S4). After that, the switch SWL is operated to switch between the check terminal RE1 and the check terminals LE1 to LE8 arranged on the left side of the battery case 10, and obtain the voltage differences VL1 to VL8 between the check terminals (step S5). If all the voltage differences VL1 to VL8 are equal to or greater than a preset airtightness threshold voltage, the battery case 10 to be inspected is determined to be a non-assembled product (steps S6 and S7). On the other hand, if any one of the voltage differences VL1 to VL8 is less than the airtightness threshold voltage, the battery case 10 to be inspected is determined to be a defective product (steps S6 and S8).

[0030] Here, the airtight threshold voltage is a value that is set in advance based on a value previously obtained by electrical potential analysis, a value determined based on an experimentally obtained normal range, the normal range of the output voltage output by one battery cell 20, etc.

[0031] As described above, in the battery module 1 according to the first embodiment, the multiple battery cells 20 are held in the battery case 10 in an unconstrained state, and the multiple battery cells 20 can be removed from the battery case 10 by pushing the push pins 31, 32 into the through holes 11, 12. This makes it possible to easily disassemble the battery module 1 according to the first embodiment without having to worry about the binding force applied to the battery cells 20. In other words, the battery module 1 according to the first embodiment can be easily disassembled.

[0032] Furthermore, in the battery module 1 according to the first embodiment, by providing the sealing members 11c, 12c and forming the conductive layers 11b, 12b in a form in which a conductive wire is embedded in an insulating layer, it becomes possible to discover assembly defects and insufficient airtightness of the battery case 10 caused, for example, by insufficient fitting of the sealing member 11c into the through hole 11. Furthermore, in the battery module 1 according to the first embodiment, sealing defects and assembly defects occurring near the sealing members can be detected by utilizing the voltage of the battery cells, so that it becomes possible to detect sealing defects and assembly defects without preparing large-scale equipment for defect detection.

[0033] Embodiment 2 In the second embodiment, a battery case 50 will be described as another example of the battery case 10. In the description of the second embodiment, the same components as those described in the first embodiment will be denoted by the same reference numerals as in the first embodiment, and the description thereof will be omitted.

[0034] Fig. 7 shows a schematic diagram of a battery module according to the second embodiment. As shown in Fig. 7, in the battery module 2 according to the second embodiment, the busbar is configured using a conductive layer formed on the inner circumferential wall of the through hole 51 incorporated in the battery case 10, without using the busbar 23 of the battery module 1 according to the first embodiment. Therefore, Fig. 8 shows a diagram for explaining the structure of the through hole provided in the battery module according to the second embodiment.

[0035] 7 and 8, in a battery case 50 according to the second embodiment, for each pair of adjacent through holes 51, conductive layers 51b formed on the inner circumferential walls of the through holes 51 are connected by a conductive member 51c. Also, an insulating layer 51a is provided around the conductive layers 51b and the conductive members 51c. The insulating layer 51a insulates a main portion of the battery case 50 from the conductive layers 51b and the conductive members 51c.

[0036] 7, the conductive layer 51b and the conductive member 51c are shown as being visible, but the surfaces of the conductive layer 51b and the conductive member 51c may be covered so that they are not visible. However, the battery case 50 is configured so that the through-holes 51 are visible in order to dismantle the battery cells 20 from the battery case 50.

[0037] Also, in the battery case 50 according to the second embodiment, inside the battery case, the cell fixing protrusion 21b presses the sealing member 11c against the conductive layer 51b, thereby transmitting the voltage of the battery cell 20 to the conductive layer 51b and the conductive member 51c via the electrode terminal 21.

[0038] As described above, in the battery module 2 according to the second embodiment, the components that make up the busbars are incorporated within the battery case 50, so that a battery pack can be formed simply by incorporating the battery cells 20 into the battery case 50.

[0039] Also, in the battery module 2 according to the second embodiment, the battery cells 20 can be easily removed from the battery case 50 by pushing the push pins into the through holes 51. In other words, the battery module 2 according to the second embodiment can also be easily disassembled.

[0040] Third embodiment In the third embodiment, a battery module 3 will be described, which is another example of the battery module 1. In the description of the third embodiment, the same components as those described in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

[0041] Fig. 9 is a diagram for explaining a battery module 3 according to the third embodiment. As shown in Fig. 9, in the battery module 3 according to the third embodiment, all of the through holes 11, 12 are closed with caps 61, 62. Moreover, it is preferable that the caps 61, 62 have an area covering the surface of the conductive layer 11b.

[0042] As described above, the battery module 3 according to the third embodiment can prevent the intrusion of dust and the like and reduce the possibility of electric leakage by covering and concealing the through holes 11, 12 and the conductive layers 11b, 12b with the caps 61, 62.

[0043] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0044] 1, 2, 3 Battery Module 10, 50 Battery Case 11, 12, 51 through holes 11a, 12a, 51a Insulating layer 11b, 12b, 51b conductive layer 11c, 12c Sealing material 20 Battery Cells 21, 22 electrode terminal 21a, 22a Cell fixing arm 21b, 22b Cell fixing protrusions 23 Busbar 31, 32 Push-in pins 40 Measurement circuit 51c Conductive material 61, 62 Cap RE1~RE8, LE1~LE8 Check terminals

Claims

1. A plurality of battery cells arranged in a stacking direction; a battery case that houses the plurality of battery cells; the battery case has a plurality of through holes penetrating the wall surfaces at positions corresponding to the plurality of battery cells on two wall surfaces facing each other in a width direction perpendicular to the stacking direction, The battery module includes a cell fixing arm that is electrically connected to each of the plurality of battery cells and elastically supports a cell fixing protrusion that fits into the corresponding through hole.

2. A sealing member is provided on the inner side of the battery case relative to the through hole so as to surround the periphery of the through hole, the sealing member being elastically deformed due to a pressing force by the cell fixing protrusion and having electrical conductivity; a conductive layer having electrical conductivity is provided on an inner peripheral wall of the through hole; The battery module according to claim 1 , wherein the sealing member is in contact with the conductive layer in a state where the sealing member is pressed by the cell fixing protrusion.

3. The battery module according to claim 2 , wherein the conductive layer includes a plurality of conductive lines embedded in an insulating member.

4. The battery module according to claim 2 , further comprising a conductive member for connecting the conductive layers formed on inner circumferential walls of the through holes to each other, for each pair of adjacent through holes.

5. The battery module according to claim 1 , further comprising caps for closing the plurality of through holes.

6. A battery case that houses a plurality of battery cells arranged in a stacking direction, a plurality of through holes penetrating the wall surfaces at positions corresponding to the plurality of battery cells on two wall surfaces facing each other in a width direction perpendicular to the stacking direction; a sealing member is provided on the inner side of the battery case relative to the through hole so as to surround the periphery of the through hole, the sealing member being elastically deformed due to a pressing force by a cell fixing protrusion that is elastically supported by a cell fixing arm that is electrically connected to an electrode of each of the plurality of battery cells, and the sealing member has electrical conductivity; a conductive layer having electrical conductivity is provided on an inner peripheral wall of the through hole; The sealing member is molded so as to contact the conductive layer when pressed into the battery case by the cell fixing protrusion.

Images