Battery module and method for manufacturing the same

Abstract

To prevent a reduction in the reaction force of a separator after foam is elastically deformed in a compression direction.SOLUTION: A battery module comprises a plurality of battery cells 100 and a separator 400. The plurality of battery cells 100 are arranged side by side in a first direction. The separator 400 is arranged between the plurality of battery cells 100. The separator 400 includes foam 410 and an elastic body 420. The foam 410 is elastically deformable in at least the first direction. The elastic body 420 defines a sealed space 10 accommodating the foam 410.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present technology relates to a battery module and a method for manufacturing the same.

Background Art

[0002] As a prior art document disclosing the configuration of a power storage device, there is International Publication No. 2019 / 142645 (Patent Document 1). The power storage device described in Patent Document 1 includes a secondary battery and a buffer plate. The buffer plate abuts against the side walls of the secondary battery facing each other. The buffer plate includes a non-deformable portion and a deformable portion. The non-deformable portion is a portion that does not substantially deform as the volume of the secondary battery changes. The non-deformable portion holds the secondary battery. The non-deformable portion has a through hole or a recess into which the deformable portion fits. The deformable portion is a portion that elastically deforms as the volume of the secondary battery changes. The deformable portion absorbs the volume change of the secondary battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For the purpose of improving the temperature characteristics of a separator disposed between a plurality of battery cells, a foam may be used in the configuration of the separator. When the foam elastically deforms in the compression direction as each of the plurality of battery cells expands or the like, the increased pressure in the bubble portion inside the foam may be released to the surroundings of the foam through the bubble portion. As a result, the reaction force of the foam decreases, and thus the reaction force of the separator may decrease after the foam elastically deforms in the compression direction.

[0005] The present technology has been made to solve the above problems, and an object thereof is to provide a battery module and a method for manufacturing the same, which can suppress a decrease in the reaction force of a separator after the foam is elastically deformed in the compression direction.

Means for Solving the Problems

[0006] The present technology provides the following battery module. [1] A plurality of battery cells arranged in a first direction, and a separator disposed between the plurality of battery cells, wherein the separator includes at least a foam that is elastically deformable in the first direction, and an elastic body that defines a sealed space for housing the foam, the battery module. Note that "defining a sealed space" includes forming a sealed space by the elastic body alone and forming a sealed space by the elastic body and other members. [2] The sealed space is formed by being surrounded by two battery cells among the plurality of battery cells in the first direction and being surrounded by the elastic body in the circumferential direction in the first direction, the battery module according to [1]. [3] In a state where the battery module is removed, the thickness of the elastic body in the first direction is thicker than the thickness of the foam in the first direction, the battery module according to [1] or [2]. [4] In a state where the battery module is removed, the product of the elastic modulus of the elastic body and the cross-sectional area in the first direction is smaller than the product of the elastic modulus of the foam and the cross-sectional area in the first direction, the battery module according to [2] or [3]. [5] The elastic body is adhered to the plurality of battery cells via an adhesive, the battery module according to any one of [2] to [4]. [6] The elastic body has a main body portion in which a recess is formed that opens in the first direction and forms the sealed space. The battery module according to any one of [1] to [5], wherein the foam is disposed inside the recess.

[0007] The present technology provides a method for manufacturing the following battery module. [7] A step of arranging a plurality of battery cells side by side in a first direction; A method for manufacturing a battery module, comprising: arranging a separator including at least a foam that is elastically deformable in the first direction and an elastic body that defines a sealed space for accommodating the foam between the plurality of battery cells. [8] The method further includes a step of preparing the separator, The step of preparing the separator includes disposing a foaming agent on the elastic body and foaming the foaming agent to form the foam. Disposing the foaming agent on the elastic body includes disposing the foaming agent in a recess formed in the elastic body and opening in the first direction. The method for manufacturing a battery module according to [7], wherein foaming the foaming agent includes foaming the foaming agent disposed in the recess.

Advantages of the Invention

[0008] According to the present technology, it is possible to suppress a decrease in the reaction force of the separator after the foam is elastically deformed in the compression direction.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts may be denoted by the same reference numerals, and the description thereof may not be repeated.

[0011] In the embodiments described below, when referring to the number, amount, etc., unless otherwise specified, the scope of the present technology is not necessarily limited to such number, amount, etc. Also, in the following embodiments, each component is not necessarily essential for the present technology, unless otherwise specified. Further, the present technology is not necessarily limited to those that exhibit all the effects mentioned in this embodiment.

[0012] In addition, in this specification, the descriptions of "comprise", "include", and "have" are in an open-ended format. That is, when a certain configuration is included, other configurations other than the said configuration may or may not be included.

[0013] Also, in this specification, when geometric terms and terms representing positional and directional relationships, such as "parallel", "orthogonal", "45° oblique", "coaxial", "along", etc. are used, these terms allow for manufacturing errors or some fluctuations. When terms representing relative positional relationships such as "upper side" and "lower side" are used in this specification, these terms are used to indicate the relative positional relationship in one state, and depending on the installation direction of each mechanism (such as turning the entire mechanism upside down, etc.), the relative positional relationship can be reversed or rotated at an arbitrary angle.

[0014] In this specification, "battery" is not limited to lithium-ion batteries, and may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, "electrode" may be a general term for the positive electrode and the negative electrode.

[0015] Also, the "battery module" can be mounted on a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a battery electric vehicle (BEV), etc. However, the use of the "battery module" is not limited to in-vehicle use.

[0016] In the drawings, the direction in which the positive and negative terminals of the battery cells are arranged is the X direction as the second direction, the direction in which a plurality of battery cells are arranged is the Y direction as the first direction, and the height direction of the battery module is the Z direction as the third direction. Also, a cross-sectional view of the battery module seen from the Y direction is referred to as a longitudinal cross-sectional view, and a cross-sectional view seen from the Z direction is referred to as a transverse cross-sectional view. Furthermore, for ease of understanding the invention, there are some places where the dimensions of each component in the drawings are shown as changed from the actual dimensions.

[0017] (Embodiment 1) First, the configuration of the battery module according to Embodiment 1 of the present technology will be described. FIG. 1 is a perspective view showing the configuration of the battery module according to Embodiment 1 of the present technology. FIG. 2 is a perspective view showing the internal configuration of the battery module according to Embodiment 1 of the present technology.

[0018] As shown in FIGS. 1 and 2, the battery module 1 according to Embodiment 1 of the present technology includes battery cells 100, end plates 200, restraining members 300, and separators 400.

[0019] A plurality of battery cells 100 are arranged in the first direction (Y direction). A separator 400, which will be described later, is interposed between the battery cells 100. The plurality of battery cells 100 sandwiched between the two end plates 200 are pressed by the end plates 200 and restrained between the two end plates 200.

[0020] The end plates 200 are provided at both ends of the plurality of battery cells 100 in the first direction (Y direction). The end plates 200 are fixed to a base such as a housing that houses the battery module 1. The end plates 200 are made of, for example, aluminum or iron.

[0021] As shown in FIG. 1, the restraint member 300 is provided at both ends in the X direction of the plurality of battery cells 100 and the end plates 200. The restraint member 300 is engaged with the end plate 200 in a state where a compressive force in the Y direction is applied to the stacked plurality of battery cells 100 and end plates 200, and then the compressive force is released, so that a tensile force acts on the restraint member 300 that connects the two end plates 200. As a reaction, the restraint member 300 presses the two end plates 200 in a direction approaching each other. As a result, the restraint member 300 restrains the plurality of battery cells 100 in the Y direction.

[0022] The separator 400 is disposed between the plurality of battery cells 100. The separator 400 abuts on the long side surfaces of the plurality of battery cells 100. The separator 400 has insulating properties. Thereby, the separator 400 insulates the plurality of battery cells 100 from each other. Details of the separator 400 will be described later.

[0023] FIG. 3 is a perspective view showing the configuration of a battery cell included in the battery module according to Embodiment 1 of the present technology.

[0024] As shown in FIG. 3, the battery cell 100 includes an electrode terminal 110, a case body 120, a gas discharge valve 130, and an electrode body 140.

[0025] 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.

[0026] The case body 120 is a container that houses the electrode body 140 and the electrolytic solution. The case body 120 has a substantially rectangular parallelepiped shape. The case body 120 is made of aluminum, an aluminum alloy, iron, or an iron alloy.

[0027] 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.

[0028] An electrode terminal 110 is disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 in the third direction (Z direction).

[0029] A pair of long side surfaces 123 and a 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 each of the upper surface 121 and the lower surface 122. Each of the pair of long side surfaces 123 faces each other with the electrode body 140 interposed therebetween in the first direction (Y direction). Each of the pair of short side surfaces 124 faces each other with the electrode body 140 interposed therebetween in the 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.

[0030] The gas discharge valve 130 breaks when the pressure inside the case body 120 becomes equal to or higher than a predetermined value. Thereby, the gas inside the case body 120 is discharged to the outside of the case body 120.

[0031] The electrode body 140 functions as a power generation element. The electrode body 140 includes a positive electrode and a negative electrode (not shown). The base material constituting the positive electrode is, for example, an aluminum alloy foil. The base material constituting the negative electrode is, for example, a copper alloy foil. The electrode body 140 is, for example, a wound type electrode body in which the positive electrode and the negative electrode are wound, or a laminated type electrode body in which the positive electrode and the negative electrode are alternately laminated.

[0032] FIG. 4 is a cross-sectional view of the battery module of FIG. 2 as viewed from the direction of the IV-IV line arrow. FIG. 5 is a longitudinal sectional view of the battery module of FIG. 2 as viewed from the direction of the V-V line arrow.

[0033] As shown in FIGS. 4 and 5, the separator 400 in the present embodiment includes a foam 410 and an elastic body 420. Further, the battery module 1 according to the present embodiment further includes an adhesive 430.

[0034] The foam 410 is a part of the separator 400 that mainly receives the pressing force associated with the expansion of the battery cell 100. The foam 410 is elastically deformable at least in the first direction (Y direction). The foam 410 in the present embodiment is elastically deformable in any of the first to third directions.

[0035] The foam 410 is in contact with the battery cell 100 in the Y direction. In the present embodiment, the foam 410 is in contact with the battery cell 100 with the adhesive 430 interposed therebetween. The foam 410 is adhered to the battery cell 100 by the adhesive 430.

[0036] The foam 410 is located substantially at the center of the separator 400. The foam 410 is surrounded by the elastic body 420 in the periphery in the Y direction. As a result, the foam 410 is accommodated in the internal space of the elastic body 420. The position of the foam 410 can be arbitrarily adjusted in the internal space of the elastic body 420 by changing the position where it adheres to the battery cell 100 with the adhesive 430.

[0037] The foam 410 can be composed of a material having electrical insulation and elasticity, such as silicone rubber, urethane rubber, or ethylene propylene rubber (EPDM), for example.

[0038] The foam 410 has a base portion 411 and a plurality of bubble portions 412. The base portion 411 is a portion that forms the outer shape of the foam 410.

[0039] The plurality of bubble portions 412 are scattered inside the base portion 411. The bubble portions 412 in the present embodiment have an open-cell structure. As a result, each of the plurality of bubble portions 412 communicates with each other. Note that this open-cell structure is not shown in the drawings for ease of understanding the invention. Also, the plurality of bubble portions 412 do not necessarily have to communicate with each other.

[0040] In addition to mainly receiving the pressing force accompanying the expansion of the battery cell 100, the foam 410 also functions as a heat insulating material. The foam 410 is excellent in heat insulation by utilizing the thermal conductivity of air in the internal space of the bubble portion 412. Therefore, when the battery cell 100 generates heat, heat transfer from the adjacent foam 410 to the surrounding components can be suppressed.

[0041] The elastic body 420 is a frame body that surrounds the foam 410 in the circumferential direction in the first direction (Y direction). Note that the elastic body 420 in the present embodiment is composed of one member, but is not limited to this configuration. The elastic body 420 may be composed of two or more members. When the elastic body 420 is composed of two or more members, the members are joined to each other by adhesion or the like.

[0042] The elastic body 420 in the present embodiment is elastically deformable in any of the first to third directions. The elastic body 420 is elastically deformable by receiving the pressing force accompanying the expansion of the battery cell 100.

[0043] The elastic body 420 is in contact with the battery cell 100 in the first direction (Y direction). The elastic body 420 in the present embodiment is in contact with the plurality of battery cells 100 while being adhered to the battery cells 100 via the adhesive 430.

[0044] The elastic body 420 can be composed of a material having electrical insulation and elasticity, such as silicone rubber, fluororubber, urethane rubber, natural rubber, styrene-butadiene rubber, butyl rubber, ethylene-propylene rubber (EPM or EPDM), butadiene rubber, isoprene rubber, norbornene rubber, or the like.

[0045] The elastic body 420 in the present embodiment is provided with a through hole 421 penetrating in the first direction (Y direction). The foam 410 is disposed inside the through hole 421 with a gap from the elastic body 420.

[0046] The elastic body 420 defines a sealed space 10 that houses the foam 410. "Defining the sealed space 10" includes forming the sealed space 10 by the elastic body 420 alone and forming the sealed space 10 by the elastic body 420 and other members. The other member may be the battery cell 100 or another elastic member. Also, although the foam 410 is surrounded by the elastic body 420 in the periphery in the first direction (Y direction), it may be configured to be surrounded by the elastic body 420 in all of the first to third directions.

[0047] The sealed space 10 is formed by being surrounded by two of the plurality of battery cells 100 in the first direction (Y direction) and being surrounded by the elastic body 420 in the circumferential direction in the first direction (Y direction). The sealed space 10 in the present embodiment is formed by being surrounded by the long side surface of the battery cell 100 and the elastic body 420, and the long side surface of the battery cell 100 and the elastic body 420 being adhered to each other by the adhesive 430. The adhesive 430 may be provided on all surfaces (both surfaces) where the foam 410 and the elastic body 420 contact the battery cell 100, or may be provided only on any one surface (one surface) where the foam 410 and the elastic body 420 contact the battery cell 100. Also, for example, the adhesive 430 may be provided on both surfaces of the elastic body 420 and the adhesive may be provided on one surface of the foam 410. When the adhesive 430 is provided only on one surface of the foam 410 and the elastic body 420, by providing the adhesive 430 on the surfaces in the same direction of the foam 410 and the elastic body 420, relative positioning with the battery cell 100 becomes easy in the assembly of the battery module.

[0048] When the separator 400 is pressed by the pressing force accompanying the expansion of the battery cell 100 and the foam 410 and the elastic body 420 are elastically deformed in the compression direction in the first direction (Y direction), the volume of the sealed space 10 becomes smaller than before they are elastically deformed.

[0049] FIG. 6 is a longitudinal sectional view showing the configuration of the separator included in the battery module according to Embodiment 1 of the present technology before being assembled into the battery module.

[0050] As shown in FIG. 6, in a state where the separator 400 is removed from the battery module, the product of the elastic modulus of the elastic body 420 and the cross-sectional area S2 in the first direction (Y direction) is smaller than the product of the elastic modulus of the foam 410 and the cross-sectional area S1 in the first direction (Y direction). Due to this relationship between the product of the elastic modulus and the cross-sectional area, the elastic body 420 is more likely to undergo elastic deformation than the foam 410.

[0051] The elastic modulus of the foam 410 is, for example, 1 MPa or more and 10 MPa or less. The elastic modulus is defined, for example, as follows. A load-displacement curve (FS curve) is obtained using a test piece of the foam having a square with a side length of 5 cm. As test conditions, the pressurization rate is 30 N / min, and the foam is pressurized up to 3.9 MPa. The elastic modulus is calculated from the slope of the FS curve when the compression ratio of the foam is between 1% and 20%. After the above test, after releasing the pressure and allowing it to stand for 2 hours, the thickness of the foam is measured with a micrometer. It is a condition for the elastic modulus of the foam 410 that the change in the thickness of the foam after the test is within 20% of the thickness of the foam before the above-described test. The elastic modulus of the elastic body can also be calculated by the same method as described above.

[0052] The cross-sectional area S1 of the foam 410 in the first direction (Y direction) is, for example, 65% or more and 120% or less of the cross-sectional area of the electrode body in the first direction (Y direction). Note that since the cross-sectional area S1 of the foam 410 in the first direction (Y direction) may vary depending on the position of the cross-section, when specifying the cross-sectional area of the foam 410, it is desirable to use, for example, the minimum value of the cross-sectional areas calculated from a plurality of longitudinal cross-sections of the foam 410.

[0053] The elastic modulus of the elastic body 420 is set to satisfy the above-described relationship between the elastic modulus and the cross-sectional area. That is, after defining the elastic modulus of the foam 410, the cross-sectional area S1 of the foam 410 in the first direction (Y direction), and the cross-sectional area S2 of the elastic body 420 in the first direction (Y direction), it is desirable that the elastic modulus of the elastic body 420 be defined so as to satisfy the above-described relationship between the elastic modulus and the cross-sectional area.

[0054] The cross-sectional area S2 of the elastic body 420 in the first direction (Y direction) is, for example, 3% or more and 30% or less of the outer shape area as viewed from the first direction (Y direction) of the case body. Since the foam body 410 mainly receives the pressing force accompanying the expansion of the battery cell 100, it is desirable that the cross-sectional area S2 of the elastic body 420 in the first direction (Y direction) be smaller than the value obtained by dividing the product of the cross-sectional area S1 of the foam body 410 in the first direction (Y direction) and the elastic modulus by the elastic modulus of the elastic body.

[0055] FIG. 7 is a cross-sectional view showing the configuration of the separator included in the battery module according to Embodiment 1 of the present technology before being assembled to the battery module.

[0056] As shown in FIG. 7, in a state where the separator 400 is removed from the battery module, the thickness T2 of the elastic body 420 in the first direction (Y direction) is thicker than the thickness T1 of the foam body 410 in the first direction (Y direction). Thereby, since the foam body 410 is suppressed from swelling in the internal space of the elastic body 420, it is easy to secure the sealed space 10 when the separator 400 is assembled to the battery module 1.

[0057] The thickness T1 of the foam body 410 in the first direction (Y direction) is, for example, 3% or more and 17% or less with respect to the thickness of the battery cell in the first direction (Y direction). The thickness T2 of the elastic body 420 in the first direction (Y direction) is, for example, 3% or more and 25% or less with respect to the thickness of the battery cell in the first direction (Y direction).

[0058] Next, a method for manufacturing the battery module 1 according to Embodiment 1 of the present technology will be described. FIG. 8 is a flowchart showing the method for manufacturing the battery module according to Embodiment 1 of the present technology. Note that the description of the assembly method of the components other than the battery cell 100 and the separator 400 is omitted.

[0059] As shown in FIG. 8, as a method for manufacturing the battery module 1 according to Embodiment 1 of the present technology, first, a separator 400 is prepared (step S1). The method for forming the separator 400 is not limited. The separator 400 may be formed by cutting a foam into a size that can be accommodated inside an elastic body and then disposing the foam inside the internal space of the elastic body, or by disposing a foaming agent, which will be described later, inside the internal space of the elastic body and causing the foam to form by foaming.

[0060] Next, a plurality of battery cells 100 are arranged side by side in the first direction (Y direction) (step S2). The plurality of battery cells 100 are arranged side by side in the first direction (Y direction) with a gap therebetween.

[0061] Next, the separator 400 is disposed between the plurality of battery cells 100 (step S3). Specifically, a separator 400 including a foam 410 that is elastically deformable at least in the first direction (Y direction) and an elastic body 420 that defines a sealed space 10 for accommodating the foam 410 is disposed between the plurality of battery cells 100. In the present embodiment, the separator 400 is adhered to the battery cell 100 with an adhesive 430.

[0062] Here, the configuration of the battery module according to the comparative example will be described. FIG. 9 is a cross-sectional view showing the configuration of the separator when the battery cell expands in the battery module according to the comparative example.

[0063] As shown in FIG. 9, the battery module 9 according to the comparative example includes a battery cell 100 and a separator 900. The separator 900 includes a first member 910 and a second member 920.

[0064] The first member 910 is a foam that is elastically deformable in the first direction (Y direction) by the pressing force due to the expansion of the battery cell 100. The second member 920 is a member having a strength such that it does not substantially undergo elastic deformation under the pressing force due to the expansion of the battery cell 100.

[0065] The first member 910 has a base portion 911 and a bubble portion 912. The bubble portion 912 has an open-cell structure. When the bubble portion 912 receives the pressing force due to the expansion of the battery cell 100, the internal space is compressed and becomes a high pressure.

[0066] The second member 920 defines a sealed space 90 that houses the first member 910. The second member 920 does not deform due to the pressing force from the battery cell 100. Therefore, the volume of the sealed space 90 is less likely to decrease compared to before receiving the pressing force from the battery cell 100. As a result, the pressure in the sealed space 90 becomes lower than the pressure in the internal space of the bubble portion 912. Since the bubble portion 912 having an open-cell structure communicates with the sealed space 90, the pressure in the internal space of the bubble portion 912 is released to the low-pressure sealed space 90 in order to maintain an equilibrium state.

[0067] The first member 910 is compressed under the pressing force from the battery cell 100, and since the pressure in the internal space of the bubble portion 912 is released to the sealed space 90 (in the direction of the arrow in FIG. 9), the pressure in the internal space of the bubble portion 912 decreases. As a result, the reaction force of the first member 910 against the expansion of the battery cell 100 decreases. Consequently, the reaction force of the separator 900 decreases.

[0068] On the other hand, in the separator 400 according to the present embodiment, as shown in FIGS. 4 and 5, the foam 410 and the elastic body 420 elastically deform under the pressing force from the battery cell 100. Therefore, as the battery cell 100 expands, the volume of the sealed space 10 becomes smaller compared to before receiving the pressing force from the battery cell 100.

[0069] When the volume of the closed space 10 decreases, the pressure inside the closed space 10 becomes high pressure. Specifically, the pressure inside the closed space 10 becomes approximately the same as the pressure in the internal space of the bubble part 412 in the foam 410. The bubble part 412 having an open-cell structure communicates with the closed space 10, but since the pressure difference between the closed space 10 and the internal space of the bubble part 412 is smaller than that in the comparative example, the release of the pressure in the internal space of the bubble part 412 into the closed space 10 is suppressed. As a result, the decrease in the pressure in the internal space of the bubble part 412 is suppressed, so that the decrease in the reaction force of the foam 410 against the expansion of the battery cell 100 is suppressed. Consequently, the decrease in the reaction force of the separator 400 is suppressed.

[0070] In the battery module 1 and its manufacturing method according to Embodiment 1 of the present technology, when the foam 410 and the elastic body 420 of the separator 400 are elastically deformed in the compression direction by the separator 400 receiving the pressing force due to the expansion of the battery cell 100 or the like, by accommodating the foam 410 in the closed space 10 formed by the elastic body 420, the closed space 10 inside and around the foam 410 can be compressed to increase the pressure. Therefore, even if the pressure in the internal space of the foam 410 increases along with the elastic deformation of the foam 410 in the compression direction, by suppressing the release of the pressure into the closed space 10 around the foam 410, the decrease in the reaction force of the foam 410 can be suppressed. As a result, the decrease in the reaction force of the separator 400 after the foam 410 is elastically deformed in the compression direction can be suppressed.

[0071] In the battery module 1 and its manufacturing method according to Embodiment 1 of the present technology, by using the foam 410 for the separator 400 and providing an internal space in the elastic body 420, the thermal conductivity of the separator 400 can be lowered by utilizing the thermal conductivity of air. Therefore, compared with the case where an elastic body having no bubble part is used for the entire separator, the decrease in the reaction force of the separator 400 due to the temperature rise of the separator 400 during the use of the battery module 1 can be suppressed.

[0072] In the battery module 1 according to Embodiment 1 of the present technology, the sealed space 10 is surrounded by two of the plurality of battery cells 100 in the first direction (Y direction), and is formed by being surrounded by the elastic body 420 in the circumferential direction in the first direction (Y direction). Thereby, when arranging the foam 410 formed inside the elastic body 420, it is possible to make the configuration such that the foam 410 can be easily inserted into the elastic body 420 from the through-hole 421.

[0073] In the battery module 1 according to Embodiment 1 of the present technology, by making the thickness T2 of the elastic body 420 thicker than the thickness T1 of the foam, in the internal space of the through-hole 421 of the elastic body 420, it is possible to easily secure the sealed space 10 without the foam 410 bulging.

[0074] In the battery module 1 according to Embodiment 1 of the present technology, in a state where the separator 400 is removed from the battery module 1, by making the product of the elastic modulus of the elastic body 420 and the cross-sectional area S2 in the first direction (Y direction) smaller than the product of the elastic modulus of the foam 410 and the cross-sectional area S1 in the first direction (Y direction), it is possible to more easily elastically deform the elastic body 420 compared to the foam 410. Thereby, the sealed space 10 formed by the elastic body 420 can be compressed and sealed more easily.

[0075] In the battery module 1 according to Embodiment 1 of the present technology, since the elastic body 420 is adhered to the battery cell 100 via the adhesive 430, it is possible to make it difficult for air to leak from between the elastic body 420 and the long side surface of the battery cell 100. This is because the elastic body 420 expands due to the internal pressure of the sealed space 10 and can be prevented from coming off from the long side surface 123 of the battery cell 100 and the pressure from decreasing. As a result, it is possible to easily ensure the sealed state and high-pressure state of the sealed space 10. Also, by attaching the foam 410 using the adhesive 430, there is an effect of facilitating positioning during assembly.

[0076] (Embodiment 2) Hereinafter, the battery module and its manufacturing method according to Embodiment 2 of the present technology will be described. Since the configuration of the separator and the manufacturing method of the foam in the battery module and its manufacturing method according to Embodiment 2 of the present technology are different from those of the battery module 1 and its manufacturing method according to Embodiment 1 of the present technology, descriptions of the configurations that are the same as those of the battery module 1 and its manufacturing method according to Embodiment 1 of the present technology will not be repeated.

[0077] FIG. 10 is a longitudinal sectional view showing the configuration of a separator included in the battery module according to Embodiment 2 of the present technology. FIG. 11 is a cross-sectional view of the separator of FIG. 10 viewed from the direction of the arrow along line XI-XI.

[0078] As shown in FIGS. 10 and 11, the battery module according to Embodiment 2 of the present technology includes a battery cell, an end plate, a restraint member, and a separator 400B. The separator 400B includes a foam 410B and an elastic body 420B.

[0079] The elastic body 420B has a main body portion 421B. A plurality of recesses 422B are formed in the main body portion 421B. The foam 410B is disposed inside the plurality of recesses 422B. Note that there may be one recess 422B.

[0080] The plurality of recesses 422B open in a first direction (Y direction) and form a sealed space 10B. The sealed space 10B is formed by surrounding five of the six surfaces surrounding the space with the recesses 422B and surrounding the remaining one surface with the long side surface of the battery cell.

[0081] FIG. 12 is a cross-sectional view showing a state in which the foam in the battery module according to Embodiment 2 of the present technology is formed from a foaming agent.

[0082] As shown in FIG. 12, in the step of preparing the separator 400B of the battery module according to Embodiment 2 of the present technology, the foaming agent 20 is disposed in the elastic body 420B. Specifically, the foaming agent 20 is disposed inside the plurality of recesses 422B.

[0083] The foaming agent 20 before foaming disposed in the concave portion 422B is foamed to form the foam 410B. Thereby, the foam 410B is disposed in the concave portion 422B of the elastic body 420B. The foam formed by foaming the foaming agent 20 adheres to the concave portion 422B. Although a plurality of concave portions 422B are arranged, one may be sufficient. In this case, in order to easily ensure the heat insulation characteristics, it is desirable that the occupancy rate of the concave portion 422B is higher than that of the main body portion.

[0084] In the battery module and its manufacturing method according to the second embodiment of the present technology, similar to the first embodiment, it is possible to suppress a decrease in the reaction force of the foam 410B. Thereby, it is possible to suppress a decrease in the reaction force of the separator 400B after the foam 410B is elastically deformed in the compression direction.

[0085] In the battery module according to the second embodiment of the present technology, since five of the six surrounding surfaces forming the sealed space 10B can be surrounded by the elastic body 420B, compared with the case where a through hole is provided in the elastic body to form the sealed space, a sealed space 10B with high sealing performance can be formed.

[0086] In the manufacturing method of the battery module according to the second embodiment of the present technology, by foaming the foaming agent 20 disposed inside the elastic body 420B to form the foam 410B, the forming process such as cutting of the foam 410B can be omitted. Therefore, the separator 400B in which the foam 410B is disposed in the inner space of the elastic body 420B can be efficiently manufactured. This is because when the foam 410B is foamed inside the concave portion 422B at a determined position of the elastic body 420B, the arrangement of the foam 410B is completed with high positional accuracy. That is, the assembling process for arrangement can be omitted.

[0087] As described above, the embodiments of the present technology have been described. It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present technology is indicated by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Description of Symbols

[0088] 1, 1A, 9 Battery module, 10, 10B, 90 Sealed space, 20 Foaming agent, 100 Battery cell, 110 Electrode terminal, 111 Positive electrode terminal, 112 Negative electrode terminal, 120 Case body, 121 Upper surface, 122 Lower surface, 123 Pair of long side surfaces, 124 Pair of short side surfaces, 130 Gas discharge valve, 140 Electrode body, 200 End plate, 300 Restraining member, 400, 400B, 900 Separator, 410, 410B Foam, 411, 911 Base portion, 412, 912 Bubble portion, 420, 420B Elastic body, 421 Through hole, 421B Body portion, 422B Recess, 430 Adhesive, 910 First member, 920 Second member, S1, S2 Cross-sectional area, T1, T2 Thickness.

Claims

1. A plurality of battery cells arranged in a first direction, and a separator disposed between the plurality of battery cells, wherein the separator includes at least a foam that is elastically deformable in the first direction, and an elastic body that defines a sealed space for housing the foam, the sealed space is formed by being surrounded by two of the plurality of battery cells in the first direction and surrounded by the elastic body in the circumferential direction in the first direction, a battery module, wherein in a state of being removed from the battery module, the product of the elastic modulus of the elastic body and the cross-sectional area in the first direction is smaller than the product of the elastic modulus of the foam and the cross-sectional area in the first direction.

2. The battery module according to claim 1, wherein in a state of being removed from the battery module, the thickness of the elastic body in the first direction is thicker than the thickness of the foam in the first direction.

3. The battery module according to claim 1, wherein the elastic body is adhered to the plurality of battery cells via an adhesive.

4. A plurality of battery cells arranged in a first direction, and a separator disposed between the plurality of battery cells, wherein the separator includes at least a foam that is elastically deformable in the first direction, and an elastic body that defines a sealed space for housing the foam, the elastic body has a main body portion that opens toward the first direction and has a recess formed to form the sealed space, a battery module, wherein the foam is disposed inside the recess.

5. A step of arranging a plurality of battery cells side by side in a first direction, and a step of disposing a separator including at least a foam that is elastically deformable in the first direction and an elastic body that defines a sealed space for housing the foam between the plurality of battery cells, the sealed space is formed by being surrounded by two of the plurality of battery cells in the first direction and surrounded by the elastic body in the circumferential direction in the first direction, a method for manufacturing a battery module, wherein in a state of being removed from the battery module, the product of the elastic modulus of the elastic body and the cross-sectional area in the first direction is smaller than the product of the elastic modulus of the foam and the cross-sectional area in the first direction.

6. A step of arranging a plurality of battery cells side by side in a first direction, and A step of disposing a separator including at least a foam that can be elastically deformed in the first direction and an elastic body that defines a sealed space for accommodating the foam between the plurality of battery cells, further including a step of preparing the separator, The step of preparing the separator includes disposing a foaming agent in the elastic body and foaming the foaming agent to form the foam, Disposing the foaming agent in the elastic body includes disposing the foaming agent in a recess formed in the elastic body and opening in the first direction, A method of manufacturing a battery module, wherein foaming the foaming agent includes foaming the foaming agent disposed in the recess.

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