Manufacturing method of battery pack

Abstract

To suppress creep deformation amount generated after delivery.SOLUTION: A manufacturing method of a battery pack 1, includes: a depression step of bringing one end surface of a laminated battery stack 5 in a lamination direction D into direct contact with a case 40, in which the battery stack has spacers 21 having a plurality of ribs 23 in contact with battery cells 10 arranged between the battery cells 10, and depressing the other end surface in the lamination direction D by a fitting 90; an activation step of activating the battery stack 5 in a depressed state; an inspection step of inspecting the activated battery stack 5; a side panel arrangement step of arranging a side panel 30 on the other end surface side; and a depression cancel step of canceling depression by the fitting 90, and bringing the other end surface into contact with the side panel 30.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a battery pack. [Background technology]

[0002] Battery packs in which a laminate is housed in a case are known (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a battery storage container that includes a cassette container that stores one lithium ion secondary battery in each gap separated by a partition plate, and an outer frame housing that stores multiple cassette containers in parallel.

[0004] Incidentally, in a battery pack, it is preferable to suppress the amount of creep deformation that occurs after shipment. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-142057 A Summary of the Invention [Problem to be solved by the invention]

[0006] In consideration of the above, an object of the present invention is to suppress the amount of creep deformation that occurs after shipment. [Means for solving the problem]

[0007] A manufacturing method for a battery pack of a first aspect of the present invention includes a pressing process in which one end face in the stacking direction of a stacked body, which is formed by placing an intermediate member having a plurality of ribs that contact the battery cells between the battery cells, is brought into direct or indirect contact with a case and the other end face in the stacking direction is pressed with a jig, an activation process in which the stacked body is activated in a pressed state, an inspection process in which the activated stacked body is inspected, a side panel placement process in which a side panel is placed on the other end face side, and a pressure release process in which the pressure applied by the jig is released and the other end face is brought into contact with the side panel.

[0008] In a battery pack manufacturing method according to a second aspect of the present invention, in the battery pack manufacturing method according to the first aspect of the present invention, the ribs are spaced apart from one another to form an air passage between the intermediate member and the battery cell.

[0009] A third aspect of the present invention is a method for manufacturing a battery pack according to the first or second aspect of the present invention, wherein the spacing between the ribs is set within a range in which, when the battery cell is pressed by the rib in the pressing process, the portion of the battery cell that is not pressed is deformed. Effect of the Invention

[0010] In the battery pack manufacturing method of the first aspect of the present invention, a pressing step is provided in which an intermediate member having a plurality of ribs is disposed between the battery cells and a stacked body is pressed, so that the battery cells are pressed by the plurality of ribs. Therefore, compared to a case in which the battery cells are pressed by a flat plate having no ribs, the pressing area is smaller and the amount of creep deformation of the stack is larger. Then, by providing a pressing release step in which the pressing by the jig is released and the other end face is brought into contact with the side panel, the stack is in a state in which the same positions as those pressed by the ribs in the pressing step are pressed by the case and the side panel. Therefore, compared to a case in which the battery cells are pressed by the flat plate and then pressed by the ribs, the amount of creep deformation that occurs after shipping of the battery pack can be suppressed.

[0011] In the battery pack manufacturing method of the second aspect of the present invention, the ribs are spaced apart from one another to form an air passage between the intermediate member and the battery cell, so that the ribs that press the battery cell in the pressing step are the members that form the air passage. Therefore, the parts used to manufacture the battery pack can be the parts that form the air passage of the battery pack.

[0012] In the battery pack manufacturing method of the third aspect of the present invention, the arrangement spacing of the multiple ribs is set within a range in which the unpressed parts of the battery cells deform when the battery cells are pressed by the ribs in the pressing process. This makes it possible to suppress the amount of creep deformation that occurs after shipment of the battery pack while maintaining battery performance during activation of the battery cells. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is an exploded perspective view showing the battery pack according to the embodiment. [Diagram 2] FIG. 2 is an exploded perspective view showing a laminate according to an embodiment. [Diagram 3] FIG. 2 is a front view showing a spacer according to the embodiment. [Figure 4] 4 is a flow diagram showing a manufacturing method of a battery pack according to an embodiment. [Diagram 5] 2 is a cross-sectional view showing a pressing process of the battery pack according to the embodiment, showing the cross section AA of FIG. 1. [Figure 6] 4A to 4C are cross-sectional views showing a side panel arrangement step of the battery pack according to the embodiment. [Figure 7] 5A to 5C are cross-sectional views showing a pressure releasing process for the battery pack according to the embodiment. [Figure 8] 4 is a graph showing changes over time in compressive load of a battery pack according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, a battery pack according to an embodiment will be described with reference to the drawings. The battery pack according to the embodiment will be described as an example of a lithium ion secondary battery used as an in-vehicle power source for an electric vehicle, a hybrid vehicle, or the like. In each drawing, the arrow UP indicates the upper side in the vertical direction of the battery pack, the arrow FR indicates the front side in the front-rear direction of the battery pack, the arrow LH indicates the left side in the left-right direction of the battery pack, and the arrow D indicates the stacking direction D of the battery stack. In the embodiment, the stacking direction D of the battery stack coincides with the front-rear direction of the battery pack.

[0015] [Battery pack 1 configuration] As shown in FIG. 1, the battery pack 1 includes a battery stack 5 as a laminate, a case 40 that houses the battery stack 5, and a side panel 30 that is disposed on the case 40.

[0016] (Battery stack 5) 1 and 2, the battery stack 5 includes a plurality of battery cells (single cells) 10, a plurality of intermediate members 20 arranged in contact with the wide faces of the battery cells 10, a pressed plate 25 arranged on the rear end side of the battery cells 10 in the stacking direction D, and a bus bar 15 that electrically connects the battery cells 10. In the battery stack 5, the battery cells 10 and the intermediate members 20 are arranged alternately in the stacking direction D.

[0017] <Battery cell 10> 2, the battery cell 10 is formed in a rectangular plate shape with the plate thickness direction being the front-rear direction. The battery cell 10 has two electrode terminals 12 on its top surface 10A. One of the two electrode terminals 12 is a positive terminal and the other is a negative terminal. Note that the battery cell 10 may have multiple pole groups arranged therein.

[0018] The battery case of the battery cell 10 is made of, for example, aluminum, and contains a wound body and an electrolyte therein.

[0019] <Intermediate member 20> The intermediate member 20 is made of, for example, insulating resin, which suppresses the transfer of heat between the battery cells 10 and insulates the battery cells 10 from each other.

[0020] As shown in FIG. 1, the intermediate member 20 includes a spacer 21 and an end plate 24.

[0021] The spacers 21 are disposed between the battery cells 10 in the stacking direction D. The spacers 21 are formed in the shape of a rectangular plate with the plate thickness direction extending in the front-rear direction.

[0022] As shown in FIG. 2, the spacer 21 includes a base portion 22 and ribs 23 formed in a comb-teeth shape.

[0023] The base portion 22 is formed in a rectangular plate shape with its thickness direction extending in the front-rear direction.

[0024] The ribs 23 are formed so as to protrude in the front-rear direction from a wide surface on one side of the base portion 22. As shown in Fig. 3, a plurality of the ribs 23 are arranged at intervals from one another, and are formed into a comb-like cross section. The ribs 23 are spaced from one another to form air passages between the spacers 21 and the battery cells 10. In other words, the battery stack 5 is stacked with the spacers 21, each having a plurality of ribs 23 that contact the battery cells 10, arranged between the battery cells 10.

[0025] The spacing between the ribs 23 is set within a range that allows the parts of the battery cells 10 that are not pressed to deform when the battery cells 10 are pressed by the ribs 23 in the pressing step described below.

[0026] 1, the end plates 24 are disposed at both ends of the battery stack 5 in the stacking direction D. The end plates 24 are formed in a rectangular plate shape with the plate thickness direction extending in the front-rear direction.

[0027] <Pressure plate 25> 1, the pressed plate 25 is formed in a rectangular plate shape with the plate thickness direction being in the front-rear direction. The pressed plate 25 is attached to the wide surface of the end plate 24 on the rear end side of the battery stack 5. The pressed plate 25 is made of, for example, metal, and has a strength sufficient to withstand pressure from a jig 90 (see FIG. 5) described later.

[0028] <Busbar 15> 2, the busbar 15 is formed, for example, in a rectangular plate shape with its plate thickness direction extending in the up-down direction in the stacking direction D. The busbar 15 electrically connects the electrode terminals 12 of adjacent battery cells 10.

[0029] (Case 40) 1, the case 40 is formed by, for example, aluminum die casting. The case 40 is formed by a bottom plate 41, side plates 42, and a front plate 43 in the shape of a rectangular box whose top and rear are open.

[0030] A concave fitting groove 42A into which the side panel 30 fits is formed extending in the vertical direction in the side plate 42. The space surrounded by the bottom plate 41, the side plate 42, the front plate 43, and the side panel 30 fitted in the fitting groove 42A constitutes an accommodation space S in which the battery stack 5 is housed.

[0031] (Side Panel 30) 1, the side panel 30 contacts the rear end of the battery stack 5 in the stacking direction D, and is detachably provided on the case 40. The side panel 30 is formed by a first portion 31 and a second portion 32 so as to have an L-shaped cross section.

[0032] The first portion 31 is formed in a rectangular plate shape with the plate thickness direction being the front-rear direction. A notch portion 31A that is open downward is formed in the first portion 31. The notch portion 31A is formed in a portion that is pressed by a jig 90 (see FIG. 5) described later.

[0033] The second portion 32 is formed in a rectangular plate shape with its thickness direction extending in the up-down direction.

[0034] 7, the battery stack 5 is housed in the case 40 in a state compressed in the stacking direction D. The battery stack 5 is housed in the case 40 in a state compressed in the stacking direction D by the front panel 43 and the side panel 30.

[0035] That is, the side panel 30 is disposed at a position where the battery stack 5 is compressed in the stacking direction D by the side panel 30 and the front plate 43 of the case 40 .

[0036] [Configuration of jig 90] 5, the jig 90 is used when manufacturing the battery pack 1. The jig 90 has a pressing portion 91 and a holding portion 92.

[0037] The pressing portion 91 is configured to be movable forward and backward in the stacking direction D relative to the holding portion 92. The pressing portion 91 may be, for example, a bolt. The holding portion 92 is formed in an L-shaped cross section and configured to hold the pressing portion 91.

[0038] [Conventional manufacturing method of battery pack 1] A conventional battery pack 1 is manufactured through a pressing process in which a jig presses the battery cells 10 with a flat plate, an activation process in which the battery cells 10 are activated, a first inspection process in which the battery cells 10 are inspected, a pressure release process in which the pressure applied by the jig to the battery cells 10 is released, a case accommodation process in which the battery stack 5 is accommodated in a case while compressed in the stacking direction D, and a second inspection process in which the battery stack 5 is inspected.

[0039] [Manufacturing method of battery pack 1] As shown in FIG. 4, the battery pack 1 is manufactured through a pressing step (step S1), an activation step (step S2), an inspection step (step S3), a side panel arrangement step (step S4), and a pressing release step (step S5).

[0040] (Pressing process) In the pressing process of step S1, as shown in Fig. 5, the battery stack 5 is placed in the accommodation space S of the case 40. In addition, a jig 90 is set on the rear end side of the case 40. Then, one end face (front face) of the battery stack 5 in the stacking direction D is brought into direct contact with the front plate 43 of the case 40, and the other end face (rear face) of the battery stack 5 in the stacking direction D is pressed in the stacking direction D by a pressing part 91.

[0041] In other words, the end plate 24 on the front end side of the battery stack 5 is brought into direct contact with the front plate 43 of the case 40, and the pressed plate 25 of the battery stack 5 is pressed in the stacking direction D by the pressing portion 91. Therefore, by using the case 40 to press the front end side of the battery stack 5 in the pressing step, some of the jigs used in the conventional manufacturing method of the battery pack 1 can be omitted.

[0042] When the battery stack 5 is pressed in the stacking direction D by the pressing portion 91 , the ribs 23 press the battery cells 10 .

[0043] The amount of compression by which the battery stack 5 is compressed by the pressing portion 91 is set to be greater than the amount of compression by which the battery stack 5 is compressed between the side panel 30 and the front plate 43 .

[0044] (activation process) In the activation process of step S2, the battery cells 10 are activated while being pressed in the stacking direction D by the pressing portions 91.

[0045] (Inspection process) In the inspection process of step S3, the activated battery cells 10 are inspected. Specifically, short-circuited battery cells 10 are detected and removed.

[0046] (Side panel placement process) 6, in the side panel arrangement process of step S4, the side panel 30 is moved downward and fitted into the fitting groove 42A (see FIG. 1) formed in the side plate 42, and attached to the case 40. That is, the side panel 30 is arranged on the rear end side of the battery stack 5.

[0047] (Pressure release process) 7 , in the pressure releasing process of step S5, the pressure applied by the jig 90 is released, and the rear end face of the battery stack 5 is brought into contact with the side panel 30. Specifically, the pressing portion 91 is retracted, the pressure applied by the jig 90 is released, and the pressed plate 25 is brought into contact with the side panel 30, and the battery stack 5 is compressed between the side panel 30 and the front panel 43.

[0048] Here, in the pressure releasing step according to the embodiment, the pressure on the battery cells 10 is not completely released, so the second inspection step that was necessary in the conventional battery pack 1 manufacturing method is not necessary.

[0049] When the battery stack 5 is compressed between the side panel 30 and the front plate 43, the ribs 23 press against the battery cells 10. The jig 90 is then removed, and the battery pack 1 is manufactured.

[0050] [Changes in compressive load on battery pack 1 over time] In the battery pack 1, the compressive load acting on the case 40 of the compressed battery stack 5 changes due to creep deformation of the battery stack 5.

[0051] In the conventional manufacturing method of the battery pack 1, the battery cells 10 were pressed by a flat plate in the pressing step, which reduced the amount of creep deformation of the battery cells 10 and increased the compression load of the battery pack 1 at the time of shipment, as shown in Fig. 8(A). This caused a problem of a large decrease in the compression load of the battery pack 1 from the time of shipment until it was released on the market.

[0052] In the manufacturing method of the battery pack 1 according to the embodiment, the battery cells 10 are pressed by the ribs 23 in the pressing step, so the amount of creep deformation of the battery cells 10 is greater than when the battery cells 10 are pressed by a flat plate, and the compression load of the battery pack 1 at the time of shipment is reduced, as shown in Fig. 8(B). Therefore, in the manufacturing method of the battery pack 1 according to the embodiment, it is possible to suppress the amount of reduction in the compression load of the battery pack 1 from shipment to when it is released on the market, compared to the conventional manufacturing method of the battery pack 1.

[0053] [Effect] The manufacturing method of the battery pack 1 of the embodiment includes a pressing process in which one end face in the stacking direction D of a stacked battery stack 5, in which spacers 21 having a plurality of ribs 23 that contact the battery cells 10 are arranged between the battery cells 10, is brought into direct contact with a case 40 and the other end face in the stacking direction D is pressed with a jig 90, an activation process in which the battery stack 5 is activated in a pressed state, an inspection process in which the activated battery stack 5 is inspected, a side panel arrangement process in which a side panel 30 is arranged on the other end face side, and a pressure release process in which the pressure by the jig 90 is released and the other end face is brought into contact with the side panel 30 (see Figure 5).

[0054] By providing a pressing step of pressing the stacked battery stack 5 with spacers 21 having a plurality of ribs 23 disposed between the battery cells 10, the battery cells 10 are pressed by the plurality of ribs 23. Therefore, compared to a case where the battery cells 10 are pressed by a flat plate not having the ribs 23, the pressing area is smaller and the amount of creep deformation of the battery stack 5 is larger. By providing a pressing release step of releasing the pressing by the jig 90 and bringing the other end face into contact with the side panel 30, the battery stack 5 is in a state where the same positions as those pressed by the ribs 23 in the pressing step are pressed by the case 40 and the side panel 30. Therefore, compared to a case where the battery cells 10 are pressed by the flat plate and then pressed by the ribs 23, the amount of creep deformation that occurs after the shipment of the battery pack can be suppressed.

[0055] In the manufacturing method of the battery pack 1 of this embodiment, the multiple ribs 23 are spaced apart from one another to form air passages between the spacer 21 and the battery cells 10 (see FIG. 3).

[0056] The multiple ribs 23 are spaced apart from one another to form an air passage between the spacer 21 and the battery cell 10, and the ribs 23 that press the battery cell 10 in the pressing step are used as components that form the air passage. Therefore, the components used to manufacture the battery pack can be used as components that form the air passage of the battery pack.

[0057] In the manufacturing method of the battery pack 1 of the embodiment, the spacing between the multiple ribs 23 is set within a range in which the portions of the battery cells 10 that are not pressed are deformed when the battery cells 10 are pressed by the ribs 23 in the pressing process.

[0058] The spacing between the multiple ribs 23 is set within a range in which the unpressed parts of the battery cells 10 deform when the battery cells 10 are pressed by the ribs 23 in the pressing process. This makes it possible to maintain battery performance during activation of the battery cells 10 while suppressing the amount of creep deformation that occurs after shipment of the battery pack.

[0059] The manufacturing method of the battery pack of the present invention has been described above based on the embodiment. However, the specific configuration is not limited to this embodiment, and design changes and the like are permitted as long as they do not deviate from the gist of the invention according to each claim of the claims.

[0060] In the embodiment, an example has been shown in which the end plate 24 on the front end side of the battery stack 5 is brought into direct contact with the front plate 43 of the case 40, and the pressed plate 25 of the battery stack 5 is pressed in the stacking direction D by the pressing portion 91. However, the end plate 24 on the front end side of the battery stack 5 may be brought into indirect contact with the front plate 43 of the case 40, and the pressed plate 25 of the battery stack 5 may be pressed in the stacking direction D by the pressing portion 91.

[0061] In the embodiment, an example has been shown in which the ribs 23 are provided on the spacer 21. However, the ribs may be provided on the spacer and the end plate.

[0062] In the embodiment, an example has been shown in which the battery stack 5 includes the end plates 24. However, the battery stack does not necessarily have to include the end plates.

[0063] In the embodiment, an example has been shown in which one battery stack 5 is housed in the case 40. However, the case may house two battery stacks 5 with an intermediate plate therebetween.

[0064] In the embodiment, the battery pack manufacturing method is an example of a lithium ion secondary battery manufacturing method, but the battery pack manufacturing method can be applied to a battery pack in which a battery stack is compressed in the stacking direction D and housed in a case. [Explanation of symbols]

[0065] 1 Battery pack 5 Battery stack (laminate) 10 Battery Cells 21 Spacer (an example of an intermediate part) 30 Side Panel 90 Jig D Stacking direction

Claims

1. a pressing step of directly or indirectly contacting one end face in the stacking direction of a stack formed by arranging intermediate members between battery cells and having a plurality of ribs that come into contact with the battery cells with a case, and pressing the other end face in the stacking direction with a jig; an activation step of activating the laminate in a pressed state; an inspection step of inspecting the activated laminate; a side panel arrangement step of arranging a side panel on the other end surface side; a pressure releasing step of releasing the pressure applied by the jig to bring the other end surface into contact with a side panel; A method for manufacturing a battery pack comprising:

2. The ribs are spaced apart from one another to form an air passage between the intermediate member and the battery cell. A method for manufacturing the battery pack according to claim 1 .

3. The arrangement intervals of the plurality of ribs are set within a range in which, when the battery cell is pressed by the ribs in the pressing step, a portion of the battery cell that is not pressed is deformed. A method for manufacturing the battery pack according to claim 1 .

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