Battery pack and manufacturing method thereof

Abstract

To simplify the step of manufacturing a battery pack by reducing the types of members.SOLUTION: The battery pack includes a battery cell 100, a housing 200, and an adhesive layer 300. The housing 200 includes: a bottom part 210 on which the battery cell 100 is mounted; and a side wall part 220 standing on the bottom part 210, and stores the battery cell 100. The adhesive layer 300 includes: a first part 310 for attaching the battery cell 100 and the bottom part 210 to each other; and a second part 320 for attaching the side wall part 220 and the bottom part 210 to each other. The first part 310 and the second part 320 are made of the same material.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present technology relates to a battery pack and a manufacturing method thereof. [Background technology]

[0002] A prior art document disclosing the configuration of a battery module is Chinese Utility Model No. 213026245 (Patent Document 1). The battery module described in Patent Document 1 includes a bottom plate and cells. A structural adhesive for bonding the cells to the bottom plate and a thermally conductive adhesive for transferring heat between the cells and the bottom plate are applied to the bottom plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Chinese Utility Model No. 213026245 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery module described in Patent Document 1, different types of adhesives are used to bond the components of the battery pack together in order to achieve the required adhesive strength or thermal conductivity. However, using different types of adhesives increases the number of component types, making the manufacturing process of the battery pack more complicated.

[0005] The present technology has been made to solve the above-mentioned problems, and aims to provide a battery pack that can reduce the number of component types and simplify the manufacturing process, and a manufacturing method thereof. [Means for solving the problem]

[0006] The present technology provides the following battery pack and manufacturing method thereof. [1] A battery cell; a housing that houses the battery cells and includes a bottom portion on which the battery cells are placed and a sidewall portion that stands upright from the bottom; an adhesive layer including a first portion that bonds the battery cell and the bottom portion and a second portion that bonds the sidewall portion and the bottom portion; The battery pack, wherein the first portion and the second portion are made of the same material. [2] The battery pack according to [1], wherein the adhesive layer is formed continuously on the bottom between the first portion and the second portion. [3] The battery pack according to [1] or [2], wherein the thickness of the first portion of the adhesive layer is greater than the thickness of the second portion. [4] further comprising an electrical component disposed inside the housing and electrically connected to the battery cell; The battery pack described in any one of [1] to [3], wherein the adhesive layer bonds the electrical component and the bottom and further includes a third portion made of the same material as the first portion and the second portion. [5] [4] The battery pack described in [4], wherein the adhesive layer is formed continuously on the bottom in a region including the first portion, the second portion, and the third portion of the adhesive layer. [6] A method for manufacturing the battery pack according to any one of [1] to [5], preparing a plate member constituting the bottom portion; applying an adhesive made of the same material to a first region on the plate member where the first portion is to be formed and a second region on the plate member where the second portion is to be formed; placing the battery cell on the first portion; and placing a side wall member that configures the side wall portion on the second portion. [Effects of the Invention]

[0007] According to the present technology, the number of types of components can be reduced and the manufacturing process of the battery pack can be simplified. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a configuration of a battery pack according to a first embodiment of the present technology; [Figure 2] 1 is a perspective view showing a configuration of a battery cell according to a first embodiment of the present technology. [Figure 3] 3 is a cross-sectional view of the battery pack of FIG. 1 as seen from the direction of the arrows along line III-III. [Figure 4] 10 is a cross-sectional view showing the configuration of a battery pack according to a second embodiment of the present technology. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof may not be repeated.

[0010] In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. Furthermore, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiments.

[0011] In this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a certain feature is included, other features may or may not be included.

[0012] Furthermore, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in a single state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0013] In this specification, the term "battery" is not limited to lithium-ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, the term "electrode" may collectively refer to a positive electrode and a negative electrode.

[0014] The "battery pack" can be installed in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs), etc. However, the use of the "battery pack" is not limited to in-vehicle use.

[0015] In the drawings, the direction in which the multiple battery cells are arranged is the Y direction as the first direction, the direction in which a pair of second side wall portions of the housing are arranged is the X direction as the second direction, and the direction in which the top and bottom surfaces of the battery cells are arranged is the Z direction as the third direction.

[0016] (Embodiment 1) 1 is a perspective view showing a configuration of a battery pack according to embodiment 1 of the present technology. As shown in FIG. 1, the battery pack 1 according to embodiment 1 of the present technology includes a plurality of battery cells 100 and a housing 200.

[0017] The plurality of battery cells 100 are lined up in a first direction (Y direction). In this embodiment, the plurality of battery cells 100 are lined up in the first direction (Y direction) with separators (not shown) interposed between the battery cells 100. The separators are insulating plates.

[0018] The housing 200 houses a plurality of battery cells 100. The housing 200 is made of, for example, aluminum or steel. The housing 200 is formed by, for example, extrusion molding.

[0019] The housing 200 in this embodiment includes a bottom portion 210, a side wall portion 220, and a cover member (not shown).

[0020] A plurality of battery cells 100 are placed on the bottom 210. The side wall 220 stands upright from the bottom 210. The bottom 210 and the side wall 220 are joined where they contact each other. In this embodiment, the bottom 210 and the side wall 220 are bonded to each other with an adhesive. A lid member is provided on the bottom 210 and the side wall 220 so as to cover the plurality of battery cells 100 from above.

[0021] The side wall portion 220 has a pair of first side wall portions 230 and a pair of second side wall portions 240. The pair of first side wall portions 230 are arranged such that one first side wall portion 230a and the other first side wall portion 230b face each other. The pair of second side wall portions 240 are arranged such that one second side wall portion 240a and the other second side wall portion 240b face each other.

[0022] The pair of first side wall portions 230 sandwich a plurality of battery cells 100 in the first direction (Y direction). In the present embodiment, the plurality of battery cells 100 are sandwiched between one first side wall portion 230a and the other first side wall portion 230b.

[0023] The pair of second sidewalls 240 connect the respective ends of the pair of first sidewalls 230 to each other in a second direction (X direction) perpendicular to the first direction (Y direction). In the present embodiment, the respective ends of the one first sidewall 230a and the other first sidewall 230b are connected to each other by one second sidewall 240a and the other second sidewall 240b. The pair of first sidewalls 230 and the pair of second sidewalls 240 are joined by an adhesive.

[0024] The stacked battery cells 100 are inserted into the housing 200 with a compressive force acting in a first direction (Y direction) on them, and then the compressive force is released, causing a tensile force to act on the pair of second side walls 240 connecting the pair of first side walls 230. In reaction to this, the pair of second side walls 240 press the pair of first side walls 230 in a direction that brings them closer to each other. As a result, the housing 200 restrains the multiple battery cells 100 in the first direction (Y direction).

[0025] As described above, the battery pack 1 of this embodiment restrains and supports the plurality of battery cells 100 by a structure (cell-to-pack structure) in which the side wall portion 220 of the housing 200 directly supports the plurality of battery cells 100. Note that the battery pack 1 is not limited to the cell-to-pack structure, and may also have a structure (cell-module-pack structure) in which a battery module including the plurality of battery cells 100 is housed inside the housing 200.

[0026] Fig. 2 is a perspective view showing the configuration of a battery cell according to embodiment 1 of the present technology. As shown in Fig. 2, the battery cell 100 is, for example, a lithium ion battery. The battery cell 100 has a rectangular shape.

[0027] Each of the plurality of battery cells 100 includes an electrode terminal 110, a case body 120, and a gas release valve 130.

[0028] The electrode terminal 110 has a positive electrode terminal 111 and a negative electrode terminal 112. The electrode terminal 110 is formed on the case body 120.

[0029] The case body 120 is a container that houses an electrode assembly and an electrolyte (not shown). The case body 120 has a substantially rectangular parallelepiped shape. The case body 120 is made of aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0030] The case body 120 has an upper surface 121, a lower surface 122, a pair of long side surfaces 123, and a pair of short side surfaces 124.

[0031] The electrode terminals 110 are disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 in the third direction (Z direction).

[0032] The pair of long side surfaces 123 and the pair of short side surfaces 124 constitute the side surfaces of the case body 120. The pair of long side surfaces 123 and the pair of short side surfaces 124 as the side surfaces of the case body 120 intersect with each of the upper surface 121 and the lower surface 122. The pair of long side surfaces 123 face each other in a first direction (Y direction). The pair of short side surfaces 124 face each other in a second direction (X direction). Each of the pair of long side surfaces 123 has a larger area than each of the pair of short side surfaces 124.

[0033] The gas exhaust valve 130 breaks when the pressure inside the case body 120 reaches or exceeds a predetermined value, thereby allowing the gas inside the case body 120 to be exhausted to the outside of the case body 120.

[0034] Fig. 3 is a cross-sectional view of the battery pack of Fig. 1, seen from the direction of the arrows along line III-III. As shown in Fig. 3, the battery pack 1 of this embodiment further includes an adhesive layer 300.

[0035] The adhesive layer 300 bonds the components of the battery pack 1 together. In this embodiment, the adhesive layer 300 bonds the components of the casing 200 together or bonds the battery cells 100 and the casing 200 together. The adhesive layer 300 is formed, for example, by applying an adhesive and then allowing the adhesive to harden.

[0036] The adhesive that forms adhesive layer 300 may be, for example, an epoxy adhesive, a urethane adhesive, an acrylic adhesive, or a silicone adhesive.

[0037] The properties required of the adhesive include adhesive strength (shear strength), insulation performance such as volume resistivity or dielectric breakdown strength, thermal conductivity (thermal conductivity), displacement tracking ability (elongation), environmental resistance, curing time, usable life, viscosity, thixotropy, and whether the adhesive is made up of only one liquid or a mixture of two liquids.

[0038] The adhesive strength is set so that the shear strength of the adhesive is greater than the force applied to the structure to be bonded. Specifically, the adhesive strength is, for example, 0.01 MPa or greater, calculated by multiplying the weight of the battery cell, the gravitational acceleration, and the impact force. The insulating performance is set so that the volume resistivity of the adhesive is greater than the insulating resistance value of the adhesive relative to the total voltage of the battery pack. Specifically, the insulating performance is, for example, 1.0×10 9 The resistance is Ω·m or more. The thermal conductivity (thermal conductivity) must be, for example, 1 W / (m·K) or more. The displacement tracking ability requires flexibility that allows it to follow the displacement of the battery pack. The displacement tracking ability requires, for example, a breaking elongation rate of 50% or more.

[0039] The environmental resistance is qualitatively set so that the shear strength of the adhesive after an environmental test is greater than the force applied to the object. The pot life is required to be at least the time required for assembly at the location where the adhesive is used, but is not limited as it depends on the manufacturing process. The curing time needs to be cured within the time until a load is applied to the adhesive, but is not particularly limited as it depends on the manufacturing process. The viscosity needs to be such that the adhesive does not drip from the perspective of assembly, but is not particularly limited as it depends on the manufacturing process. The thixotropy is not particularly limited as it depends on the manufacturing process.

[0040] The adhesive layer 300 includes a first portion 310 and a second portion 320. The first portion 310 bonds the battery cell 100 to the bottom portion 210. The second portion 320 bonds the sidewall portion 220 to the bottom portion 210.

[0041] The first portion 310 and the second portion 320 are made of the same material. Because the first portion 310 and the second portion 320 are made of a single adhesive layer 300, they can be easily made of a single type of material. The term "same material" includes cases where the materials are substantially the same. Specifically, "same" includes minute variations in the ratio of the components that make up the adhesive, such as variations that occur during manufacturing.

[0042] The first portion 310 is disposed at least partially between the battery cell 100 and the bottom portion 210. In the present embodiment, the first portion 310 is disposed entirely between the battery cell 100 and the bottom portion 210.

[0043] The second portion 320 is disposed at least partially between the side wall portion 220 and the bottom portion 210. In the present embodiment, the second portion 320 is disposed entirely between one of the first side wall portions 230a and the bottom portion 210.

[0044] Between the first portion 310 and the second portion 320, the adhesive layer 300 is formed continuously on the bottom portion 210. Therefore, in this embodiment, there is no boundary between the first portion 310 and the second portion 320.

[0045] The first portion 310 has a thickness t1. The second portion 320 has a thickness t2. The thickness of the adhesive layer 300 refers to the thickness in the normal direction from the plane of the bottom portion 210. In this embodiment, the normal direction is along the third direction (Z direction).

[0046] The thickness t1 of the first portion 310 refers to the thickness between the bottom 210 and the lower surface 122 of the battery cell 100. However, it is desirable to determine the thickness based on the thickness near the center away from the edge of the lower surface 122 so that the R-shape of the boundary between the lower surface 122 and the side surface of the battery cell 100 does not affect the thickness t1.

[0047] The thickness t2 of the second portion 320 may vary on the XY plane due to variations in the assembly of the bottom portion 210 and one of the first sidewall portions 230a during manufacturing, which may cause one of the first sidewall portions 230a to be inclined relative to the bottom portion 210. In this case, the thickness t2 of the second portion 320 is calculated by averaging the thicknesses at multiple locations.

[0048] Variations in the height dimension in the third direction (Z direction) may occur among the multiple battery cells 100 due to variations in processing during manufacturing. Furthermore, when manufacturing the battery pack 1, the multiple battery cells 100 may be manufactured with a constant height based on the top surfaces of the cells.

[0049] In this case, the thickness of the adhesive layer 300 directly below each of the multiple battery cells 100 varies for each battery cell 100. Therefore, in the present embodiment, the thickness t1 of the first portion 310 of the adhesive layer 300 is greater than the thickness t2 of the second portion 320. As a result, even if the thickness of the adhesive layer 300 changes depending on the positional relationship with each battery cell 100, the thickness t1 of the first portion 310 is greater than the thickness t2 of the second portion 320, making it easy to adjust the position relative to the top surface of the battery cell 100 and cause the adhesive to follow.

[0050] In addition, when the height dimensions of the battery cells 100 vary and the heights of the multiple battery cells 100 are determined based on the top surfaces of the battery cells 100, the thickness t1 of the first portion 310 may be such that the minimum thickness of the thickness t1 of the first portion is thicker than the thickness t2 of the second portion.

[0051] Here, a method for manufacturing the battery pack 1 according to this embodiment will be described. First, a plate member that forms the bottom portion 210 is prepared. Next, an adhesive made of the same material is applied to the first region R1 on the plate member where the first portion 310 will be formed and the second region R2 on the plate member where the second portion 320 will be formed.

[0052] Next, the battery cell 100 is placed on the first portion 310. As a result, the plate member that constitutes the bottom portion 210 and the battery cell 100 are bonded together by the first portion 310 of the adhesive layer 300. Next, the side wall member that constitutes the side wall portion 220 is placed on the second portion 320. As a result, the plate member that constitutes the bottom portion 210 and the side wall member that constitutes the side wall portion 220 are bonded together by the second portion 320 of the adhesive layer 300, and the housing 200 is formed.

[0053] The order of bonding the plate members to the battery cells 100 and the plate members to the side wall members is not limited, and the plate members and the side wall members may be bonded before the plate members and the battery cells 100, or they may be bonded simultaneously.

[0054] In the battery pack 1 according to the first embodiment of the present technology, the number of types of components in the adhesive layer 300 can be reduced by using adhesives of the same material, compared to when different types of adhesives are used to bond the battery cells 100 or the side wall 220 to the bottom 210 of the housing 200, and therefore the manufacturing process of the battery pack 1 can be simplified.

[0055] In the battery pack 1 according to the first embodiment of the present technology, the same adhesive material is used to bond the battery cells 100 and the bottom 210 of the housing 200, and the sidewalls 220 and the bottom 210 of the housing 200, thereby eliminating the possibility of unintended chemical reactions occurring when different adhesive materials are used. Furthermore, there is no need to consider differences in curing time for each adhesive. Furthermore, there is no need to manage the amount of each adhesive applied, which allows for efficient manufacturing of the battery pack 1.

[0056] In the battery pack 1 according to embodiment 1 of the present technology, the adhesive layer 300 is formed continuously on the bottom 210 between the first portion 310 and the second portion 320, thereby eliminating the boundary between the first portion 310 and the second portion 320, thereby suppressing peeling of the adhesive starting from the boundary and improving the sealing performance within the housing 200.

[0057] In the battery pack 1 according to the first embodiment of the present technology, the thickness t1 of the first portion 310 of the adhesive layer 300 is greater than the thickness t2 of the second portion 320. Therefore, when the height dimensions of the plurality of battery cells 100 vary and the heights of the plurality of battery cells 100 are determined based on the top surfaces of the battery cells 100, the first portion 310 can be made thicker to ensure an adjustment margin for the height positions of the battery cells 100. This allows the battery cells 100 and the bottom 210 to be bonded together without affecting the alignment of the battery cells 100 in the height direction.

[0058] In the manufacturing method of the battery pack 1 according to the first embodiment of the present technology, the manufacturing process of the battery pack 1 can be simplified by using adhesives of the same material, compared to when different adhesives are used to bond the battery cells 100 or the side wall portion 220 to the bottom portion 210 of the housing 200, since the process of applying different types of adhesives can be eliminated.

[0059] (Embodiment 2) Hereinafter, a battery pack according to embodiment 2 of the present technology will be described. The battery pack according to embodiment 2 has a different housing configuration from battery pack 1 according to embodiment 1 of the present technology, and therefore, the description of the configuration that is the same as battery pack 1 according to embodiment 1 of the present technology will not be repeated.

[0060] 4 is a cross-sectional view showing the configuration of a battery pack according to embodiment 2 of the present technology. As shown in FIG. 4, a battery pack 1A according to embodiment 2 includes a plurality of battery cells 100, a housing 200, an adhesive layer 300A, and an electrical component 400.

[0061] The electrical component 400 is, for example, a junction box. The electrical component 400 is disposed inside the housing 200. The electrical component 400 is electrically connected to the battery cells 100. The electrical component 400 is electrically connected to at least one of the plurality of battery cells 100 by a bus bar (not shown).

[0062] The adhesive layer 300A includes a first portion 310A, a second portion 320A, and a third portion 330A. The third portion 330A is made of the same material as the first portion 310A and the second portion 320A. The third portion 330A bonds the electrical component 400 and the bottom portion 210 together.

[0063] The first portion 310A is disposed at least partially between the battery cell 100 and the bottom portion 210. In the present embodiment, the first portion 310A is disposed entirely between the battery cell 100 and the bottom portion 210, and is disposed to protrude from both ends thereof.

[0064] The second portion 320A is disposed at least partially between the side wall portion 220 and the bottom portion 210. In the present embodiment, the second portion 320A is disposed entirely between one of the first side wall portions 230a and the bottom portion 210, and is disposed to protrude from the end portion.

[0065] The third portion 330A is disposed at least partially between the electrical component 400 and the bottom portion 210. In the present embodiment, the third portion 330A is disposed entirely between the electrical component 400 and the bottom portion 210, and is disposed protruding from the end portion. In this manner, the first portion 310A, the second portion 320A, and the third portion 330A also include the portions of the adhesive layer 300A that protrude from between the components to be bonded.

[0066] In the region including the first portion 310A, the second portion 320A, and the third portion 330A of the adhesive layer 300A, the adhesive layer 300A is formed continuously on the bottom portion 210. Therefore, no boundaries are formed between the first portion 310A, the second portion 320A, and the third portion 330A.

[0067] The thickness t1 of the first portion 310A is greater than the thickness t2 of the second portion 320A and the thickness t3 of the third portion 330A. As a result, when the height dimensions of the multiple battery cells 100 vary and the heights of the multiple battery cells 100 are determined based on the top surfaces of the battery cells 100, the first portion 310A can be made thicker to ensure an adjustment margin for the height positions of the battery cells 100.

[0068] The third portion 330A is formed by applying an adhesive made of the same material as that of the first portion 310A and the second portion 320A to a third region R3 on the plate member constituting the bottom portion 210 where the third portion 330A is formed, and then placing the electrical component 400 on the third portion 330A, thereby adhering the electrical component 400 to the bottom portion 210.

[0069] In the battery pack 1A according to the second embodiment of the present technology, the third portion 330A, which bonds the electrical component 400 to the bottom 210, is made of the same adhesive material as the first portion 310A and the second portion 320A. This reduces the number of component types for the adhesive layer 300A compared to when different types of adhesive are used to bond the various components of the battery pack 1A, thereby simplifying the manufacturing process of the battery pack 1A.

[0070] In the battery pack 1A according to the second embodiment of the present technology, the adhesive layer 300A is formed continuously on the bottom 210 in the region including the first portion 310A, the second portion 320A, and the third portion 330A, thereby eliminating the boundaries between the first portion 310A, the second portion 320A, and the third portion 330A, thereby suppressing peeling of the adhesive starting from the boundaries, and improving the sealing performance within the housing 200.

[0071] In the above-described embodiment, the adhesive layer is continuous and includes at least the first and second portions, but is not limited to this embodiment. From the viewpoint of reducing the amount of adhesive used, the adhesive layer may be formed by using only a minimum amount of adhesive, and multiple adhesives made of the same material may be arranged discontinuously.

[0072] Although the embodiments of the present technology have been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0073] 1, 1A battery pack, 100 battery cell, 110 electrode terminal, 111 positive terminal, 112 negative terminal, 120 case body, 121 upper surface, 122 lower surface, 123 pair of long sides, 124 pair of short sides, 130 gas release valve, 200 housing, 210 bottom, 220 side wall portion, 230, 230a, 230b first side wall portion, 240, 240a, 240b second side wall portion, 300, 300A adhesive layer, 310, 310A first portion, 320, 320A second portion, 330A third portion, 400 electrical component, R1 first region, R2 second region, R3 third region, t1, t2, t3 thickness.

Claims

1. A plurality of battery cells arranged in a first direction; a housing that houses the plurality of battery cells, the housing including a bottom portion on which the plurality of battery cells are placed and a sidewall portion that stands upright from the bottom; an adhesive layer including a first portion that bonds the plurality of battery cells to the bottom portion and a second portion that bonds the sidewall portion to the bottom portion; the first portion and the second portion are made of the same material, the first portion is disposed entirely between the plurality of battery cells and the bottom, and the second portion is disposed entirely between the side wall portion and the bottom.

2. The battery pack according to claim 1 , wherein the adhesive layer is formed continuously on the bottom between the first portion and the second portion.

3. 3. The battery pack according to claim 1, wherein the thickness of the first portion of the adhesive layer is greater than the thickness of the second portion.

4. an electrical component disposed inside the housing and electrically connected to the plurality of battery cells; 3. The battery pack according to claim 1, wherein the adhesive layer bonds the electrical component and the bottom portion together and further includes a third portion made of the same material as the first portion and the second portion.

5. The battery pack according to claim 4 , wherein the adhesive layer is formed continuously on the bottom in a region including the first portion, the second portion, and the third portion of the adhesive layer.

6. A method for manufacturing the battery pack according to claim 1 or 2, comprising: preparing a plate member constituting the bottom portion; applying an adhesive made of the same material to a first region on the plate member where the first portion is to be formed and a second region on the plate member where the second portion is to be formed; placing the plurality of battery cells on the first portion; and placing a side wall member that configures the side wall portion on the second portion.

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