Battery module

Abstract

To suppress degradation in reaction force of a separator against expansion of battery cells by using a simple configuration.SOLUTION: A plurality of battery cells 100 are aligned in a first direction. A separator 400 is disposed between the plurality of battery cells 100. The separator 400 includes an elastic body 410 which is elastically deformable at least in the first direction. The elastic body 410 has a first portion 411. The first portion 411 has a frame shape which extends around an axis in the first direction and internally defines a sealed space 10. In the first direction, the thickness of the first portion 411 in an unloaded condition is 1.30 times or more and 2.87 times or less a thickness T of the first portion 411 when disposed between the plurality of battery cells 100 and elastically deformed in a compression direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present technology relates to a battery module. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2020-4556 (Patent Document 1) is a prior art document that discloses the configuration of a buffer sheet for a battery module. The buffer sheet for a battery module described in Patent Document 1 comprises a plate-shaped base portion and an elastic protrusion portion. The elastic protrusion portion is formed to protrude from the base portion toward the target surface of the battery cell. The elastic protrusion portion elastically supports the battery cell when it expands in a curved shape due to charging of the battery cell, and applies a reaction force to the battery cell when it contracts due to discharging of the battery cell.

[0003] Japanese Patent Laid-Open Publication No. 2010-238554 (Patent Document 2) is a prior art document that discloses the configuration of a holder for an energy storage element. The holder described in Patent Document 2 supports a plurality of energy storage elements. The holder includes an elastic body and an injection part. The elastic body includes a sealed hollow part. The injection part injects gas into the hollow part. As the pressure in the hollow part increases, the energy storage elements are pressurized. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-4556 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-238554 Summary of the Invention [Problem to be solved by the invention]

[0005] In the buffer sheet for battery modules described in Patent Document 1, as the elastic protrusions elastically deform, the load required for elastic deformation of the elastic protrusions increases, which can prevent the elastic protrusions from deforming sufficiently, potentially reducing the reaction force of the separator against the expansion of the battery cells.

[0006] In the holder for the electric storage element described in Patent Document 2, the pressure inside the hollow portion is adjusted by an injection portion, which makes the structure complicated.

[0007] The present technology has been made to solve the above-mentioned problems, and aims to provide a battery module that has a simple configuration and can suppress a decrease in the separator's reaction force against the expansion of the battery cell. [Means for solving the problem]

[0008] The present technology provides the following battery module. [1] a plurality of battery cells arranged in a first direction; separators between the plurality of battery cells; the separator includes an elastic body that is elastically deformable in at least the first direction, the elastic body has a first portion that extends around an axis in the first direction and has a frame shape that defines an enclosed space therein; a thickness of the first portion in an unloaded state in the first direction that is 1.30 to 2.87 times the thickness of the first portion in an elastically deformed state in a compression direction while being disposed between the plurality of battery cells. [2] the first portion abuts against at least one battery cell among the plurality of battery cells at a first abutment surface in the first direction; The battery module according to [1], wherein the first contact surface has an uneven shape. [3] the first portion abuts on the first abutment surface with one of two battery cells between which the separator is sandwiched, among the plurality of battery cells; [2] The battery module according to [2], wherein the width of the first portion narrows in the first direction from the other of the two battery cells toward the one of the two battery cells. [4] The battery module according to any one of [1] to [3], wherein the elastic body further has a connection portion located at an end of the first portion in the first direction and connecting the frame-shaped peripheral edges of the first portion. [5] the elastic body further includes a second portion located outside the first portion when viewed from the first direction and having a frame shape extending around an axis in the first direction, the second portion abuts against at least one battery cell among the plurality of battery cells at a second abutment surface in the first direction; The battery module according to any one of [1] to [4], wherein the thickness of the second portion in the first direction when in contact with the at least one battery cell is approximately the same as the thickness of the first portion when disposed between the plurality of battery cells and elastically deformed in the compression direction. [6] [5] The battery module according to [5], wherein a gap is provided between the first portion and the second portion in a direction perpendicular to the first direction. [7] the elastic body further includes a second portion located outside the first portion when viewed from the first direction and having a frame shape extending around an axis in the first direction, the first portion abuts against at least one battery cell among the plurality of battery cells at a first abutment surface in the first direction; the second portion abuts against the at least one battery cell at a second abutment surface in the first direction; the first portion has a first width of a part of a frame shape in a direction perpendicular to the first direction at an end portion opposite to a side on which the first abutment surface is located in the first direction, the second portion has a second width of a part of the frame shape in a direction perpendicular to the first direction at an end portion opposite to a side on which the second abutment surface is located in the first direction, The battery module according to [1], wherein the second width is wider than the first width. [8] the elastic body further includes a second portion located outside the first portion when viewed from the first direction and having a frame shape extending around an axis in the first direction, the first portion abuts on a first abutment surface with one of two battery cells between which the separator is sandwiched, among the plurality of battery cells; The battery module described in [1], wherein the first portion faces the second portion and has a tapered surface that, in an unloaded state, slopes from the outside to the inside around an axis in the first direction as it moves from the other of the plurality of battery cells to the one of the plurality of battery cells. [9] The battery module according to any one of [1] to [8], wherein the separator further includes a heat insulating material disposed in the sealed space and having an internal space.

[10] The battery module according to any one of [1] to [9], further comprising an adhesive layer that bonds the elastic body and the plurality of battery cells in the first direction. [Effects of the Invention]

[0009] According to the present technology, it is possible to suppress a decrease in the reaction force of the separator against the expansion of the battery cell with a simple configuration. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a configuration of a battery module according to a first embodiment of the present technology. [Figure 2] 1 is a perspective view showing an internal configuration of a battery module according to a first embodiment of the present technology. [Figure 3] 1 is a perspective view showing a configuration of a battery cell included in a battery module according to a first embodiment of the present technology. [Figure 4] 4 is a cross-sectional view of the battery module of FIG. 2 as viewed from the direction of the arrows along line IV-IV. [Figure 5] 3 is a cross-sectional view of the battery module of FIG. 2 as viewed from the direction of the arrows VV line. [Figure 6]1 is a cross-sectional view showing a state in which no load is applied to a separator included in a battery module according to a first embodiment of the present technology. [Figure 7] 1 is a cross-sectional view showing a state in which pressure is applied to a battery cell from a sealed space in a separator when the battery cell included in the battery module according to Embodiment 1 of the present technology expands. [Figure 8] 4 is a cross-sectional view showing the load required for separators to support battery cells included in the battery module according to the first embodiment of the present technology. FIG. [Figure 9] 10 is a graph showing the relationship between the ratio of the thickness after compressive deformation to the thickness before compressive deformation of separators in battery modules according to the first embodiment and a comparative example, and the load. [Figure 10] 10 is a cross-sectional view showing a configuration of a battery module according to a second embodiment of the present technology. [Figure 11] FIG. 10 is a cross-sectional view showing the configuration of a battery module according to a third embodiment of the present technology. [Figure 12] FIG. 10 is a cross-sectional view showing the configuration of a battery module according to a fourth embodiment of the present technology. [Figure 13] FIG. 10 is a cross-sectional view showing the configuration of a battery module according to a fifth embodiment of the present technology. [Figure 14] FIG. 13 is a cross-sectional view showing the configuration of a battery module according to a sixth embodiment of the present technology. [Figure 15] FIG. 13 is a cross-sectional view showing the configuration of a battery module according to a seventh embodiment of the present technology. [Figure 16] FIG. 13 is a cross-sectional view showing a configuration of a battery module according to an eighth embodiment of the present technology. [Figure 17] FIG. 13 is a cross-sectional view showing the configuration of a separator in a battery module according to a ninth embodiment of the present technology when no load is applied. [Figure 18] 18 is a cross-sectional view of the battery module of FIG. 17, seen from the direction of the arrows along line XVIII-XVIII. [Figure 19] 13 is a cross-sectional view showing the configuration of a battery module according to a ninth embodiment of the present technology in a state where a separator is compressively deformed. FIG. [Figure 20]13 is a cross-sectional view showing the configuration of a separator in a battery module according to a tenth embodiment of the present technology when no load is applied. FIG. [Figure 21] 13 is a cross-sectional view showing the configuration of a battery module according to a tenth embodiment of the present technology in a state where a separator is compressed and deformed. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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).

[0015] 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.

[0016] The "battery module" 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 module" is not limited to in-vehicle use.

[0017] In the drawings, the direction in which the positive and negative terminals of the battery cells are aligned is the X direction as a second direction, the direction in which the multiple battery cells are aligned is the Y direction as a first direction, and the direction in which the top and bottom surfaces of the battery cells are aligned is the Z direction as a third direction. Furthermore, to facilitate understanding of the present technology, the dimensions of each component in the drawings may be shown differently from the actual dimensions.

[0018] (Embodiment 1) First, a configuration of a battery module according to embodiment 1 of the present technology will be described. Fig. 1 is a perspective view showing a configuration of a battery module according to embodiment 1 of the present technology. Fig. 2 is a perspective view showing an internal configuration of the battery module according to embodiment 1 of the present technology.

[0019] As shown in FIGS. 1 and 2, a battery module 1 according to a first embodiment of the present technology includes a battery cell 100, an end plate 200, a binding member 300, and a separator 400.

[0020] The multiple battery cells 100 are lined up in a first direction (Y direction). Separators 400, which will be described later, are arranged between the battery cells 100. The multiple battery cells 100 sandwiched between the two end plates 200 are pressed by the end plates 200 via the separators 400, and are constrained between the two end plates 200.

[0021] The end plates 200 are provided on 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.

[0022] As shown in FIG. 1 , the restraining members 300 are provided on both ends of the multiple battery cells 100 and end plates 200 in the X direction. When the restraining members 300 are engaged with the end plates 200 while a compressive force in the Y direction is applied to the stacked multiple battery cells 100 and end plates 200, and the compressive force is then released, a tensile force acts on the restraining members 300 connecting the two end plates 200. In reaction to this, the restraining members 300 press the two end plates 200 in a direction that brings them closer to each other. As a result, the restraining members 300 restrain the multiple battery cells 100 in the Y direction.

[0023] The separators 400 are disposed between the plurality of battery cells 100. The separators 400 are also disposed between the battery cells 100 located at the ends in the Y direction among the plurality of battery cells 100 and the end plates 200. The separators 400 abut against the long sides of the plurality of battery cells 100 or the long sides of the end plates 200.

[0024] The separators 400 have insulating properties, and thus insulate the battery cells 100 from one another, or from the battery cells 100 and the end plates 200. Details of the separators 400 will be described later.

[0025] FIG. 3 is a perspective view showing a configuration of a battery cell included in the battery module according to the first embodiment of the present technology.

[0026] As shown in FIG. 3, the battery cell 100 includes an electrode terminal 110, a case 120, a gas release valve 130, and an electrode body 140.

[0027] The electrode terminal 110 is formed on the case 120. The electrode terminal 110 has a positive electrode terminal 111 and a negative electrode terminal 112. The positive electrode terminal 111 and the negative electrode terminal 112 are arranged side by side in the second direction (X direction).

[0028] The case 120 is a container that houses the electrode assembly 140 and the electrolyte. The case 120 has a substantially rectangular parallelepiped shape. The case 120 is made of aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0029] The case 120 has an upper surface 121, a lower surface 122, a pair of long sides 123, and a pair of short sides 124.

[0030] 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).

[0031] The pair of long side surfaces 123 and the pair of short side surfaces 124 constitute the side surfaces of the case 120. The pair of long side surfaces 123 and the pair of short side surfaces 124 as the side surfaces of the case 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) with the electrode body 140 therebetween. The pair of short side surfaces 124 face each other in a second direction (X direction) with the electrode body 140 therebetween. Each of the pair of long side surfaces 123 has an area larger than each of the pair of short side surfaces 124.

[0032] The gas exhaust valve 130 breaks when the pressure inside the case 120 reaches or exceeds a predetermined value, thereby allowing the gas inside the case 120 to be exhausted to the outside of the case 120.

[0033] The electrode body 140 functions as a power generating element. The electrode body 140 includes a positive electrode and a negative electrode (not shown). The substrate constituting the positive electrode is, for example, aluminum alloy foil. The substrate constituting the negative electrode is, for example, copper alloy foil. The electrode body 140 is, for example, a wound electrode body in which the positive electrode and the negative electrode are wound, or a laminated electrode body in which the positive electrode and the negative electrode are alternately laminated.

[0034] Fig. 4 is a cross-sectional view of the battery module of Fig. 2 as seen from the direction of the arrows IV-IV. Fig. 5 is a cross-sectional view of the battery module of Fig. 2 as seen from the direction of the arrows VV.

[0035] 4 and 5, the separator 400 according to this embodiment includes an elastic body 410. The battery module 1 according to this embodiment further includes an adhesive layer 500.

[0036] Elastic body 410 is elastically deformable in at least a first direction (Y direction). Elastic body 410 in this embodiment is elastically deformable in all directions including the first direction (Y direction), the second direction (X direction), and the third direction (Z direction).

[0037] The elastic body 410 may be made of an electrically insulating and elastic material such as silicone rubber, fluororubber, urethane rubber, natural rubber, styrene butadiene rubber, butyl rubber, ethylene propylene rubber (EPM or EPDM), butadiene rubber, isoprene rubber, or norbornene rubber.

[0038] The elastic body 410 has a frame-shaped first portion 411 that extends around an axis in a first direction (Y direction). In the present embodiment, the first portion 411 is configured from one member, but is not limited to this configuration. The first portion 411 may be configured from two or more members. When the first portion 411 is configured from two or more members, the members are joined to each other by adhesive or the like.

[0039] The first portion 411 abuts against at least one battery cell 100 of the plurality of battery cells 100 in the first direction (Y direction) at a first abutment surface 412. In this embodiment, the first portion 411 abuts against one 100a of two battery cells 100 sandwiching the separator 400 therebetween at the first abutment surface 412.

[0040] The adhesive layer 500 bonds the elastic body 410 and the plurality of battery cells 100 together in the first direction (Y direction). In the present embodiment, the adhesive layer 500 bonds the first portion 411 to the other of the two sandwiched battery cells 100b at an end of the first portion 411 opposite to the side where the first contact surface 412 is located in the first direction (Y direction). Note that the adhesive layer 500 does not necessarily have to be provided on the battery module 1.

[0041] The first portion 411 is sandwiched between the multiple battery cells 100 in the first direction (Y direction) and elastically deforms in the compression direction. The first portion 411 elastically deforms in the compression direction has a thickness T.

[0042] The thickness T of the first portion 411 can be calculated, for example, by subtracting the thickness of the end plate 200 and the thickness of each of the multiple battery cells 100 from the overall length of the battery module 1 in the first direction (Y direction), and dividing the result by the number of separators 400.

[0043] The first portion 411 defines an enclosed space 10 therein. "Defining the enclosed space 10" includes forming the enclosed space 10 using the elastic body 410 alone, and forming the enclosed space 10 using the elastic body 410 together with another member. The other member may be a battery cell 100 or another member having elasticity.

[0044] In this embodiment, the sealed space 10 is formed by being surrounded by two of the multiple battery cells 100 in the first direction (Y direction) and by being surrounded by the first portion 411 around the axis of the first direction (Y direction).

[0045] FIG. 6 is a cross-sectional view showing a state in which no load is applied to the separator included in the battery module according to the first embodiment of the present technology.

[0046] 6, before the components of the battery module 1 are assembled, the separator 400 is in an unloaded state, in which it is not pressed by the battery cells 100. In the unloaded state, the first portion 411 of the separator 400 has a thickness T0 in the first direction (Y direction).

[0047] When the first portion 411 is sandwiched and pressed between the battery cells 100 in an unloaded state, the first portion 411 elastically deforms in the compression direction. As a result, as shown in Figures 5 and 6, the first portion 411 elastically deforms so that the thickness T0 of the first portion 411 becomes the thickness T.

[0048] When the first portion 411 elastically deforms so that the thickness T0 of the first portion 411 becomes the thickness T, the sealed space 11 in the first portion 411 in the no-load state is compressed. As a result, the pressure in the compressed sealed space 10 increases compared to the sealed space 11 in the no-load state. The pressure P in the sealed space 10 is applied to the battery cell 100.

[0049] FIG. 7 is a cross-sectional view showing a state in which pressure is applied to a battery cell from a sealed space in a separator when the battery cell included in the battery module according to the first embodiment of the present technology expands.

[0050] 7, the battery cells 100 may expand due to charging of the battery module 1, etc. In this case, the pressure P in the sealed space 10 of the first portion 411 acts as a reaction force against the expansion of the battery cells 100. Therefore, it is necessary to set an appropriate pressure P against the expansion of the battery cells 100.

[0051] The pressure P in the sealed space 10 can be adjusted by the degree of change in volume of the sealed space 10 before and after compressive deformation. In this embodiment, the pressure P in the sealed space 10 is set by adjusting the ratio (T0 / T) of the thickness of the first portion 411 before and after compressive deformation, which is related to the change in volume of the sealed space 10.

[0052] FIG. 8 is a cross-sectional view showing the load required for separators to support battery cells included in the battery module according to the first embodiment of the present technology.

[0053] If no load is applied to restrain the battery cell 100, when the battery cell 100 vibrates, the electrode assembly 140 may become displaced inside the case 120, resulting in damage to the electrode assembly 140. To avoid this, as shown in Fig. 8, it is necessary to apply a load F to restrain the battery cell 100 and prevent the electrodes from shifting due to friction between the case 120 and the electrode assembly 140 during vibration. The ratio (T0 / T) of the thickness of the first portion 411 before and after compressive deformation is defined as the pressure P for applying the load F.

[0054] The ratio (T0 / T) of the thickness of the first portion 411 before and after compressive deformation can be calculated using the load F according to Boyle's law: T0 / T = (load F + atmospheric pressure) / atmospheric pressure (Equation 1).

[0055] Furthermore, when calculating the load F, a temperature change is added to the calculation formula for the load F as a parameter for the environmental change after the battery cell 100 is completed. Specifically, the environmental temperature in an unloaded state when the battery cell 100 is assembled is assumed to be 25°C, and the environmental temperature after the battery cell 100 is completed is assumed to be -30°C. Then, the load F can be calculated by the following formula: Load F = Density of electrode body × Thickness of battery cell × Gravitational acceleration × Vibration acceleration / Friction coefficient between electrode body and case / Number of contact surfaces between electrode body and case × ((273 + 25°C) / (273 - 30°C)) (Formula 2).

[0056] Table 1 shows various conditions such as the density of the electrode body that are assumed to define the ratio of the thickness before and after the elastic body is compressed and deformed.

[0057] [Table 1]

[0058] The conditions of the battery cell 100 are as shown in Table 1. The load F varies depending on the specifications of the battery cell. As shown in Table 1, in this embodiment, the density of the electrode body 140 is 2.1 g / cm 3 More than 2.6g / cm 3 The following is the result.

[0059] The vibration acceleration is assumed to be 12G. The vibration acceleration was set at 12G, taking into account a safety factor of 1.5 from the maximum vibration acceleration of 8G in the vibration characteristic evaluation of the United Nations recommended transport test (UN test) for lithium-ion batteries. Furthermore, the friction coefficient between the electrode body and the case is assumed to be 0.05.

[0060] By substituting the density of the electrode body 140 and the like into the above-mentioned formula 2, the load F can be calculated to be equal to or greater than 0.030 MPa and equal to or less than 0.187 MPa.

[0061] By substituting the calculated load F into the above-mentioned formula 1, T0 / T is calculated to be 1.30 to 2.87 times. That is, in the first direction (Y direction), the thickness T0 of the first portion 411 in an unloaded state is 1.30 to 2.87 times the thickness T of the first portion 411 in a state where it is arranged between multiple battery cells 100 and elastically deformed in the compression direction. This allows an appropriate pressure P in the sealed space 10 to be set.

[0062] FIG. 9 is a graph showing the relationship between the ratio of the thickness after compressive deformation to the thickness before compressive deformation of the separators in the battery modules according to the first embodiment and the comparative example, and the load.

[0063] The battery module according to the comparative example differs from the battery module according to the present embodiment in that the separator is a solid elastic body without an enclosed space. As shown in FIG. 9, when the elastic body is solid, the load required to change the thickness increases as the compressive deformation increases, and the elastic body according to the comparative example is less susceptible to elastic deformation. Therefore, the separator is less likely to absorb the expansion that occurs during the use of the battery cells. This increases the reaction force of the battery cells on the end plates and restraining members. Therefore, the end plates and restraining members must be made stronger, which creates the problem of increasing the mass of the battery module.

[0064] On the other hand, in the present embodiment, air is compressed in the sealed space 11 inside the elastic body 410. Compared to the separator according to the comparative example, air can be compressed and deformed more easily than an elastic body, so the load required for compression and deformation is smaller. This allows for a reduction in the mass and weight of the battery module, as will be described in detail later.

[0065] In the method for manufacturing the battery module 1 according to this embodiment, first, the separator 400 is prepared. The separator 400 is formed by, for example, injection molding.

[0066] Next, multiple battery cells 100 are arranged side by side in a first direction (Y direction). Next, an adhesive layer 500 is applied to one side of a separator 400. Next, the separator 400 is placed between the multiple battery cells 100. Next, the separator 400 is adhered to one of the two sandwiched battery cells 100 with the adhesive layer 500. Thereafter, the separator 400 is pressed together with the end plate from the first direction (Y direction) to elastically deform the first portion 411. As a result, the separator 400 is compressively deformed in the first direction (Y direction), and a battery module 1 is completed in which an enclosed space 10 under pressure P is formed.

[0067] In the battery module 1 according to the first embodiment of the present technology, the separator 400 includes an elastic body 410 having a frame-shaped first portion 411. When the pressure P in the sealed space 10 inside the first portion 411 is the reaction force of the separator 400 against the expansion of the battery cells 100, the thickness T of the elastic body 410 after compressive deformation in the stacking direction of the battery cells 100 is set to a ratio of 1.30 to 2.87 times the thickness T0 under no load. This ensures the pressure P necessary to hold the electrode assembly in place without causing damage due to displacement during vibration. Furthermore, compared to a separator made of a solid elastic body, the increase in load upon compression is small, so the increase in reaction force can be suppressed even if the battery cells expand during use. As a result, the strength of the end plates and restraining members can be reduced, thereby reducing the mass of these components. Furthermore, by defining the thickness T of the elastic body 410 after compressive deformation as the thickness T0 in the no-load state, it is possible to obtain the pressure P required to counter the reaction force of the battery cells 100 in the sealed space 10 of the elastic body 410, and therefore the separator 400 can have a simpler configuration than when a sealed space is provided in the separator and the internal pressure of the sealed space is adjusted using a separate pressure adjustment structure. As a result, the simple configuration can prevent a decrease in the reaction force of the separator 400 in response to the expansion of the battery cells 100.

[0068] In the battery module 1 according to embodiment 1 of the present technology, the battery cell 100 and the elastic body 410 are bonded together by the adhesive layer 500, which makes it possible to easily position the separator 400 on the battery cell 100, thereby facilitating the assembly of the battery module 1.

[0069] Battery modules according to second to tenth embodiments of the present technology will be described below. The battery modules according to second to tenth embodiments of the present technology differ from the battery module 1 according to the first embodiment of the present technology in the configuration of the separator, and therefore, the description of the configuration that is the same as that of the battery module 1 according to the first embodiment of the present technology will not be repeated. Note that, in the following embodiments, although the drawings show cases where an adhesive layer is provided and cases where it is not provided, the adhesive layer is not essential. Also, in accordance with the description of each embodiment, at least one state of the separator before and after compressive deformation is shown.

[0070] (Embodiment 2) Fig. 10 is a cross-sectional view showing the configuration of a battery module according to embodiment 2 of the present technology. As shown in Fig. 10, the battery module according to embodiment 2 of the present technology includes a battery cell 100, an end plate, a restraining member, a separator 400A, and an adhesive layer 500. The separator 400A includes an elastic body 410A.

[0071] The first portion 411A of the elastic body 410A abuts, in the first direction (Y direction), on a first abutment surface 412A with at least one battery cell 100a among the plurality of battery cells 100. The first abutment surface 412A has an uneven shape.

[0072] In the battery module according to embodiment 2 of the present technology, the elastic body 410A and the battery cell 100a are brought into contact with each other at the convex portion of the uneven shape of the first contact surface 412A, thereby increasing the contact pressure compared to when the contact is made on a flat surface, thereby making it possible to create a configuration in which the internal pressure of the sealed space 11 is less likely to escape to the outside from the contact position.

[0073] (Embodiment 3) Fig. 11 is a cross-sectional view showing the configuration of a battery module according to embodiment 3 of the present technology. As shown in Fig. 11, the battery module according to embodiment 3 of the present technology includes a battery cell 100, an end plate, a restraining member, a separator 400B, a first adhesive layer 501B, and a second adhesive layer 502B. The separator 400B includes an elastic body 410B.

[0074] The first portion 411B of the elastic body 410B abuts, in the first direction (Y direction), on a first abutment surface 412B with at least one battery cell 100a among the multiple battery cells 100. The first abutment surface 412B has an uneven shape.

[0075] The first portion 411B is bonded to the other of the two battery cells 100b by a first adhesive layer 501B at the end opposite to the side where the first contact surface 412B is located. The first portion 411B is bonded to one of the two battery cells 100a at the first contact surface 412B via a second adhesive layer 502B.

[0076] In the battery module according to the third embodiment of the present technology, the elastic body 410B and the battery cell 100 are brought into contact at the convex portion of the uneven shape of the first contact surface 412B, thereby increasing the contact pressure compared to when the contact is made on a flat surface, and by firmly fixing the first contact surface 412B to the battery cell 100 with the second adhesive layer 502B, it is possible to create a configuration in which the internal pressure of the sealed space is less likely to escape to the outside from the contact position.

[0077] (Fourth embodiment) Fig. 12 is a cross-sectional view showing the configuration of a battery module according to embodiment 4 of the present technology. As shown in Fig. 12, the battery module according to embodiment 4 of the present technology includes a battery cell 100, an end plate, a restraining member, and a separator 400C. The separator 400C includes an elastic body 410C.

[0078] The first portion 411C of the elastic body 410C abuts, in the first direction (Y direction), on a first abutment surface 412C with at least one battery cell 100a of the multiple battery cells 100. The first abutment surface 412C has a convex shape.

[0079] In the battery module according to the fourth embodiment of the present technology, the elastic body 410C and the battery cell 100 are brought into contact with each other at the convex shape of the first contact surface 412C, thereby increasing the contact pressure compared to when the contact is made on a flat surface, thereby making it possible to create a configuration in which the internal pressure of the sealed space 11 is less likely to escape to the outside from the contact position.

[0080] (Embodiment 5) Fig. 13 is a cross-sectional view showing the configuration of a battery module according to embodiment 5 of the present technology. As shown in Fig. 13, the battery module according to embodiment 5 of the present technology includes a battery cell 100, an end plate, a restraining member, and a separator 400D. The separator 400D includes an elastic body 410D.

[0081] A first portion 411D of the elastic body 410D abuts against one 100a of the two battery cells 100 between which the separator 400D is sandwiched, at a first abutment surface 412D.

[0082] The width of the first portion 411D narrows in the first direction (Y direction) from the other battery cell 100b to the one battery cell 100a of the two battery cells.

[0083] In the battery module according to the fifth embodiment of the present technology, by narrowing the width of the elastic body 410D from one end to the other end in the first direction (Y direction), the elastic body 410D can be easily elastically deformed at the beginning of its elastic deformation, making it easier to increase the pressure in the sealed space.

[0084] (Embodiment 6) Fig. 14 is a cross-sectional view showing the configuration of a battery module according to embodiment 6 of the present technology. As shown in Fig. 14, the battery module according to embodiment 6 of the present technology includes a battery cell 100, an end plate, a restraining member, and a separator 400E. The separator 400E includes an elastic body 410E.

[0085] The first portion 411E of the elastic body 410E has a main portion 413E and a tapered portion 414E. The main portion 413E is wider in a direction perpendicular to the first direction (Y direction) than the tapered portion 414E. Note that the width of the first portion 411E may be narrowed in multiple steps from one side to the other in the first direction (Y direction).

[0086] In the battery module according to the sixth embodiment of the present technology, the first portion 411E has a tapered portion 414E that is narrower than the main portion 413E, which makes it easier for the elastic body 410E to elastically deform at the beginning of its elastic deformation, thereby making it easier to increase the pressure in the sealed space.

[0087] (Embodiment 7) Fig. 15 is a cross-sectional view showing the configuration of a battery module according to embodiment 7 of the present technology. As shown in Fig. 15, the battery module according to embodiment 7 of the present technology includes a battery cell 100, an end plate, a restraining member, and a separator 400F. The separator 400F includes an elastic body 410F.

[0088] The elastic body 410F has a first portion 411F and a connecting portion 420F. The connecting portion 420F is located at the end of the first portion 411F in the first direction (Y direction). In the present embodiment, the connecting portion 420F abuts against the battery cell 100.

[0089] The connecting portion 420F connects the frame-shaped peripheries of the first portion 411F together. In the present embodiment, the connecting portion 420F connects the entire periphery of the frame-shaped periphery of the first portion 411F. Note that the connecting portion 420F is not limited to this configuration. For example, the connecting portion 420F may have a mesh-like shape or the like when viewed from the first direction (Y direction) so as to connect parts of the frame-shaped peripheries together.

[0090] In the battery module according to embodiment 7 of the present technology, the frame-shaped periphery of the first portion 411F is connected by the connection portion 420F, so that when the separator 400 is placed between the battery cells 100 by gripping it, for example, the frame shape of the first portion 411F is less likely to deform, making the separator 400 easier to handle.

[0091] (Embodiment 8) Fig. 16 is a cross-sectional view showing the configuration of a battery module according to embodiment 8 of the present technology. As shown in Fig. 16, the battery module according to embodiment 8 of the present technology includes a battery cell 100, an end plate, a restraining member, and a separator 400G. The separator 400G includes an elastic body 410G and a heat insulating material 430G.

[0092] Heat insulating material 430G is disposed in sealed space 10 of elastic body 410G. Heat insulating material 430G contains air inside and exhibits high heat insulating properties. Heat insulating material 430G is made of, for example, a porous material or glass fiber. Heat insulating material 430G may be made of an inorganic filler (for example, ceramics such as alumina) and a polymer material.

[0093] In the battery module according to embodiment 8 of the present technology, by arranging an insulating material 430G in the sealed space 10 of the elastic body 410G, it is possible to give the separator 400G a reaction force against the battery cell 100 and insulating functions without increasing the thickness of the separator 400G, compared to when the elastic body 410G and the insulating material 430G are arranged overlapping in the first direction (Y direction).

[0094] (Embodiment 9) Fig. 17 is a cross-sectional view showing a configuration of a separator in a battery module according to embodiment 9 of the present technology when no load is applied. Fig. 18 is a cross-sectional view of the battery module in Fig. 17 as viewed from the direction of the arrows along line XVIII-XVIII. Fig. 19 is a cross-sectional view showing a configuration of a battery module according to embodiment 9 of the present technology when the separator is compressively deformed.

[0095] 17 to 19, the battery module according to the ninth embodiment of the present technology includes a battery cell 100, an end plate, a restraining member, and a separator 400H. The separator 400H includes an elastic body 410H.

[0096] The elastic body 410H has a first portion 440H and a second portion 450H. The first portion 440H abuts against at least one battery cell 100a of the multiple battery cells 100 at a first abutment surface 441H in the first direction (Y direction).

[0097] The second portion 450H is located outside the first portion 440H when viewed from the first direction (Y direction), and has a frame shape extending around an axis in the first direction (Y direction).

[0098] The second portion 450H abuts against at least one battery cell 100a of the plurality of battery cells 100 at a second abutment surface 451H in the first direction (Y direction).

[0099] In a direction perpendicular to the first direction (Y direction), a gap G is provided between the first portion 440H and the second portion 450H. In this embodiment, the gap G is provided between the first portion 440H and the second portion 450H around the entire axial circumference in the first direction (Y direction).

[0100] The first portion 440H has a first width W1 of a portion of the frame shape in a direction perpendicular to the first direction (Y direction) at the end opposite to the side where the first abutment surface 441H is located.

[0101] The second portion 450H has a second width W2 of a portion of the frame shape in a direction perpendicular to the first direction (Y direction) at an end opposite to the side where the second contact surface 451H is located. The second width W2 is wider than the first width W1.

[0102] As shown in FIG. 19, the thickness t of the second portion 450H in the first direction (Y direction) when it is in contact with at least one battery cell 100 is approximately the same as the thickness T of the first portion 440H when it is arranged between multiple battery cells 100 and elastically deformed in the compression direction.

[0103] In the battery module according to embodiment 9 of the present technology, the elastic body 410H has a first portion 440H and a second portion 450H, so that the first portion 440H defines the sealed space 10 and the second portion 450H supports the battery cell 100.

[0104] In the battery module according to embodiment 9 of the present technology, by providing a gap G between the first portion 440H and the second portion 450H, when the first portion 440H falls toward the second portion 450H during compressive deformation of the elastic body 410H, the first portion 440H is less likely to interfere with the second portion 450H.

[0105] In the battery module according to embodiment 9 of the present technology, by making the second width W2 of the second portion wider than the first width W1 of the first portion 440H, the first portion 440H for sealing the inside of the elastic body 410H is easily deformed, and the second portion 450H for retaining the compressed pressure is less likely to collapse, making it easier to maintain the pressure in the sealed space 10 of the elastic body 410H.

[0106] (Embodiment 10) Fig. 20 is a cross-sectional view showing a configuration of a separator in a battery module according to embodiment 10 of the present technology when no load is applied, and Fig. 21 is a cross-sectional view showing a configuration of a separator in a battery module according to embodiment 10 of the present technology when the separator is compressively deformed.

[0107] 20 and 21, the battery module according to the tenth embodiment of the present technology includes a battery cell 100, an end plate, a restraining member, and a separator 4001. The separator 4001 includes an elastic body 410I.

[0108] The elastic body 410I has a first portion 440I and a second portion 450I. The first portion 440I abuts against one 100a of two sandwiched battery cells 100 of the multiple battery cells 100 at a first abutment surface 441I in the first direction (Y direction).

[0109] The second portion 450I is located outside the first portion 440I when viewed from the first direction (Y direction), and has a frame shape extending around an axis in the first direction (Y direction).

[0110] The second portion 450I abuts against at least one battery cell 100a of the plurality of battery cells 100 at a second abutment surface 451I in the first direction (Y direction).

[0111] The first portion 440I has a tapered surface 442I. The tapered surface 442I faces the second portion 450I, and in an unloaded state, is inclined from the outside to the inside around an axis in the first direction (Y direction) as it moves from the other 100b to the one 100a of the multiple battery cells 100. When a load is applied to the first portion 440I, the load is applied obliquely, and the first portion 440I is therefore likely to fall inward.

[0112] In the battery module according to the tenth embodiment of the present technology, by providing a tapered surface 442I on the side of the first portion 440I facing the second portion 450I, the first portion 440I can be easily folded inward when the elastic body 410I is compressed and deformed, thereby making it possible to achieve a configuration in which the first portion 440I and the second portion 450I are less likely to interfere with each other.

[0113] In each embodiment, the separators arranged between multiple battery cells have been described, but the same configuration as the separators described above can also be applied to separators arranged between battery cells and end plates. Furthermore, in this specification, "same dimensions" means that the dimensions are the same as the design values, excluding manufacturing tolerances.

[0114] 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]

[0115] 1 battery module, 10, 11 sealed space, 100, 100a, 100b battery cell, 110 electrode terminal, 111 positive electrode terminal, 112 negative electrode terminal, 120 case, 121 upper surface, 122 lower surface, 123 pair of long sides, 124 pair of short sides, 130 gas release valve, 140 electrode body, 200 end plate, 300 restraining member, 400, 400A, 400B, 400C, 400D, 400E, 400F, 400G, 400H, 400I separator, 410, 410A, 410B, 410C, 410D, 410E, 410F, 410G, 410H, 410I Elastic body, 411, 411A, 411B, 411C, 411D, 411E, 411F, 440H, 440I first portion, 412, 412A, 412B, 412C, 412D, 441H, 441I first abutment surface, 413E main portion, 414E tapered portion, 420F connecting portion, 430G insulating material, 442I tapered surface, 450H, 450I second portion, 451H, 451I second abutment surface, 500 adhesive layer, 501B first adhesive layer, 502B second adhesive layer, T, T0, t thickness, W1 first width, W2 second width.

Claims

1. a plurality of battery cells arranged in a first direction; separators between the plurality of battery cells; the separator includes an elastic body that is elastically deformable in at least the first direction, the elastic body has a first portion that extends around an axis in the first direction and has a frame shape that defines an enclosed space therein; a thickness of the first portion in an unloaded state in the first direction is 1.30 to 2.87 times the thickness of the first portion in a state in which the first portion is disposed between the plurality of battery cells and elastically deformed in a compression direction; each of the plurality of battery cells includes a case having a pair of side surfaces facing each other in the first direction, and an electrode body housed in the case; the sealed space is defined by the side surface and the first portion of each of two battery cells adjacent in the first direction among the plurality of battery cells.

2. A plurality of battery cells arranged in a first direction; separators between the plurality of battery cells; the separator includes an elastic body that is elastically deformable in at least the first direction, the elastic body has a first portion that extends around an axis in the first direction and has a frame shape that defines an enclosed space therein; a thickness of the first portion in an unloaded state in the first direction is 1.30 to 2.87 times the thickness of the first portion in a state in which the first portion is disposed between the plurality of battery cells and elastically deformed in a compression direction; the first portion abuts against at least one battery cell among the plurality of battery cells at a first abutment surface in the first direction; The battery module, wherein the first contact surface has an uneven shape.

3. the first portion abuts on the first abutment surface with one of two battery cells between which the separator is sandwiched, among the plurality of battery cells; The battery module according to claim 2 , wherein a width of the first portion narrows in the first direction from the other of the two battery cells toward the one of the two battery cells.

4. A plurality of battery cells arranged in a first direction; separators between the plurality of battery cells; the separator includes an elastic body that is elastically deformable in at least the first direction, the elastic body has a first portion that extends around an axis in the first direction and has a frame shape that defines an enclosed space therein; a thickness of the first portion in an unloaded state in the first direction is 1.30 to 2.87 times the thickness of the first portion in a state in which the first portion is disposed between the plurality of battery cells and elastically deformed in a compression direction; The elastic body further includes a connection portion located at an end of the first portion in the first direction and connecting frame-shaped peripheral edges of the first portion.

5. A plurality of battery cells arranged in a first direction; separators between the plurality of battery cells; the separator includes an elastic body that is elastically deformable in at least the first direction, the elastic body has a first portion that extends around an axis in the first direction and has a frame shape that defines an enclosed space therein; a thickness of the first portion in an unloaded state in the first direction is 1.30 to 2.87 times the thickness of the first portion in a state in which the first portion is disposed between the plurality of battery cells and elastically deformed in a compression direction; the elastic body further includes a second portion located outside the first portion when viewed from the first direction and having a frame shape extending around an axis in the first direction, the second portion abuts against at least one battery cell among the plurality of battery cells at a second abutment surface in the first direction; a thickness of the second portion in the first direction when in contact with the at least one battery cell is approximately the same as a thickness of the first portion in a state where the second portion is disposed between the plurality of battery cells and elastically deformed in a compression direction.

6. The battery module according to claim 5 , wherein a gap is provided between the first portion and the second portion in a direction perpendicular to the first direction.

7. A plurality of battery cells arranged in a first direction; separators between the plurality of battery cells; the separator includes an elastic body that is elastically deformable in at least the first direction, the elastic body has a first portion that extends around an axis in the first direction and has a frame shape that defines an enclosed space therein; a thickness of the first portion in an unloaded state in the first direction is 1.30 to 2.87 times the thickness of the first portion in a state in which the first portion is disposed between the plurality of battery cells and elastically deformed in a compression direction; the elastic body further includes a second portion located outside the first portion when viewed from the first direction and having a frame shape extending around an axis in the first direction, the first portion abuts against at least one battery cell among the plurality of battery cells at a first abutment surface in the first direction; the second portion abuts against the at least one battery cell at a second abutment surface in the first direction; the first portion has a first width of a part of a frame shape in a direction perpendicular to the first direction at an end portion opposite to a side on which the first abutment surface is located in the first direction, the second portion has a second width of a part of a frame shape in a direction perpendicular to the first direction at an end portion opposite to a side on which the second abutment surface is located in the first direction, The second width is greater than the first width.

8. A plurality of battery cells arranged in a first direction; separators between the plurality of battery cells; the separator includes an elastic body that is elastically deformable in at least the first direction, the elastic body has a first portion that extends around an axis in the first direction and has a frame shape that defines an enclosed space therein; a thickness of the first portion in an unloaded state in the first direction is 1.30 to 2.87 times the thickness of the first portion in a state in which the first portion is disposed between the plurality of battery cells and elastically deformed in a compression direction; the elastic body further includes a second portion located outside the first portion when viewed from the first direction and having a frame shape extending around an axis in the first direction, the first portion abuts on one of two battery cells between which the separator is sandwiched, at a first abutment surface, of the plurality of battery cells; the first portion faces the second portion and has a tapered surface that, in an unloaded state, slopes from the outside to the inside around an axis in the first direction as it moves from the other one of the plurality of battery cells to the one of the plurality of battery cells.

9. The battery module according to claim 1 or 2, wherein the separator further includes a heat insulating material disposed in the sealed space and having an internal space.

10. The battery module according to claim 1 or 2, further comprising an adhesive layer that bonds the elastic body and the plurality of battery cells together in the first direction.

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