Battery module

Abstract

To provide a battery module having a separator that can maintain its function as a heat insulator even when the battery cell is deformed and has high temperatures.SOLUTION: A separator 400 includes a main body portion 410 and embedded portions 420 embedded in a plurality of through holes 420h provided in the main body portion 410, and the main body portion 410 is made of an insulating material having better insulating performance than the embedded portions 420, and the embedded portions 420 are made of an elastic material having better elastic performance than the main body portion 410, and the distance between one inner wall surface of the inner diameter of the through holes 420h and another inner wall surface located perpendicular to the one inner wall surface at the point where the distance is shortest is 60 mm or less.SELECTED DRAWING: Figure 8

Description

[Technical Field]

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

[0002] Japanese Patent Application Laid-Open No. 2021-140968 (Patent Document 1) is a prior art document that discloses the configuration of a heat insulating material for a battery module. The heat insulating material described in Patent Document 1 includes a heat insulating section that is arranged opposite the surface of the battery cell, and a buffer section that is more susceptible to compressive deformation than the heat insulating section, with at least a portion of the buffer section being arranged closer to the surface of the battery than the heat insulating section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-140968 Summary of the Invention [Problem to be solved by the invention]

[0004] The heat insulating material described in Patent Document 1 has an insulating part and a buffer part that is more susceptible to compressive deformation than the insulating part, thereby improving the heat insulating material's ability to conform to deformation. However, no consideration has been given to what would happen if the temperature of the battery cell increased and the buffer part disappeared in addition to the deformation of the battery cell.

[0005] The present technology has been made to solve the above-mentioned problems, and aims to provide a battery module equipped with a separator that can maintain its function as an insulating material even when the battery cell is deformed or at high temperatures. [Means for solving the problem]

[0006] The present technology provides the following battery module.

[0007] [1] A battery module comprising: a plurality of battery cells arranged in a first direction; and a separator sandwiched between the plurality of battery cells, wherein the separator includes a main body portion and an embedded portion embedded in a plurality of through holes provided in the main body portion; the main body portion is made of a heat insulating material having better heat insulating performance than the embedded portion; the embedded portion is made of an elastic material having better elastic performance than the main body portion; and the distance between one inner wall surface of the inner diameter of the through hole and another inner wall surface located in a perpendicular direction to the one inner wall surface is 60 mm or less at a point where the distance is shortest.

[0008] [2] The battery module according to [1], wherein the length of the embedded portion in the first direction is longer than the length of the main body portion.

[0009] [3] The battery module according to [1] or [2], wherein the embedded portion melts at a predetermined temperature or higher, but the main body portion does not melt at the predetermined temperature or higher.

[0010] [4] A battery module according to any one of [1] to [3], wherein when viewed from the first direction, the shape of the embedded portion has one of a solid circular shape, a solid elliptical shape, a solid cross shape, a hollow circular shape, or a hollow elliptical shape.

[0011] [5] A battery module described in any one of [1] to [4], wherein when viewed from the first direction, the shape of the embedded portion has, when viewed in an imaginary plane perpendicular to the first direction, a first region extending in a second direction included in the imaginary plane, and a second region extending in a third direction included in the imaginary plane and perpendicular to the second direction.

[0012] [6] The battery module according to any one of [1] to [5], wherein the separator is covered with a laminate film. [Effects of the Invention]

[0013] According to the present technology, it is possible to provide a battery module including a separator that can maintain its function as a heat insulator even when the battery cell is deformed or at high temperatures. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view showing the configuration of a battery module according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing the internal configuration of the battery module of the first embodiment. [Figure 3] 1 is a perspective view showing the configuration of a battery cell of a battery module according to a first embodiment. [Figure 4] FIG. 2 is a perspective view showing the configuration of a separator of the battery module according to the first embodiment. [Figure 5] FIG. 5 is a cross-sectional view taken along the line VV in FIG. 4. [Figure 6] 1 is a schematic diagram of a first state (normal state) in which a separator is sandwiched between battery cells. [Figure 7] FIG. 10 is a schematic diagram of the separator in a second state (expanded) in which the separator is sandwiched between battery cells. [Figure 8] 10 is a first schematic cross-sectional view showing the relationship between the deformation amount of a battery cell and the diameter of a through-hole. FIG. [Figure 9] 10 is a second schematic cross-sectional view showing the relationship between the deformation amount of the battery cell and the diameter of the through-hole. FIG. [Figure 10] 10 is a diagram showing the relationship between the diameter of a through hole and the amount of deformation of a battery cell. FIG. [Figure 11] FIG. 10 is a cross-sectional view showing the configuration of a separator according to a second embodiment. [Figure 12] FIG. 10 is a cross-sectional view showing the structure of a separator according to a third embodiment. [Figure 13] FIG. 10 is a side view showing the configuration of a separator according to a fourth embodiment. [Figure 14] FIG. 10 is a side view showing the configuration of a separator according to a fifth embodiment. [Figure 15] FIG. 13 is a side view showing the configuration of a separator according to a sixth embodiment. [Figure 16] FIG. 13 is a side view showing the configuration of a separator according to a seventh embodiment. [Figure 17] FIG. 13 is a cross-sectional view showing the structure of a separator according to an eighth embodiment. [Figure 18]FIG. 13 is a cross-sectional view showing the structure of a separator according to a ninth embodiment. [Figure 19] FIG. 22 is a cross-sectional view showing the structure of a separator according to a tenth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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.

[0016] 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. In the embodiments described below, each component is not necessarily essential to the present technology, unless otherwise specified. The present technology is not necessarily limited to those that achieve all of the effects mentioned in the present embodiments.

[0017] In this specification, the words "comprise," "include," and "have" are open-ended, meaning that when a certain feature is included, other features may or may not be included.

[0018] When geometric terms and terms expressing positional and directional relationships, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along" are used in this specification, 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 by changing the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0019] 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.

[0020] 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.

[0021] In the drawings, the direction in which multiple battery cells are lined up is the Y direction as a first direction, the direction in which the positive and negative terminals of the battery cells are lined up and included in the imaginary plane when viewed on a virtual plane perpendicular to the first direction is the second direction (X direction), and the direction in which the top and bottom surfaces of the battery cells are lined up and included in the virtual plane and perpendicular to the second direction is the third direction (Z direction). To facilitate understanding of the present technology, the dimensions of each component in the drawings may be shown differently from the actual dimensions.

[0022] (Embodiment 1) The configuration of the battery module of embodiment 1 will be described below. Fig. 1 is a perspective view showing the configuration of a battery module 1, and Fig. 2 is a perspective view showing the internal configuration of the battery module 1.

[0023] 1 and 2, a battery module 1 includes battery cells 100, end plates 200, binding members 300, and separators 400.

[0024] 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.

[0025] 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.

[0026] Referring to 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.

[0027] The separators 400 are disposed between the plurality of battery cells 100. The separators 400 are 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.

[0028] 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.

[0029] 3 is a perspective view showing the configuration of a battery cell 100 included in the battery module 1. Referring to FIG. 3, the battery cell 100 includes an electrode terminal 110, a case 120, a gas release valve 130, and an electrode body 140.

[0030] 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).

[0031] 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.

[0032] The case 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. 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).

[0033] 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.

[0034] 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.

[0035] 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.

[0036] (Separator 400) Next, the configuration of separator 400 will be described with reference to Figures 4 and 5. Figure 4 is a perspective view showing the configuration of separator 400, and Figure 5 is a cross-sectional view taken along line VV in Figure 4.

[0037] Separator 400 includes a main body portion 410 and embedded portions 420 embedded in a plurality of through holes 420h provided in main body portion 410. Main body portion 410 is a heat insulating material having better heat insulating performance than embedded portions 420, and embedded portions 420 are an elastic material having better elastic performance than main body portion.

[0038] The main body 410 has an upper surface 411, a lower surface 412, a pair of long side surfaces 413, and a pair of short side surfaces 414. The lower surface 412 faces the upper surface 411 in the third direction (Z direction).

[0039] The pair of long side surfaces 413 and the pair of short side surfaces 414 constitute the side surfaces of the separator 400. The pair of long side surfaces 413 and the pair of short side surfaces 414 as the side surfaces of the separator 400 intersect with the upper surface 411 and the lower surface 412, respectively. The pair of long side surfaces 413 face each other in the first direction (Y direction). The pair of short side surfaces 414 face each other in the second direction (X direction). Each of the pair of long side surfaces 413 has a larger area than each of the pair of short side surfaces 414.

[0040] The size and thickness of the separator 400 need only be such that it does not protrude from the battery cell 100 when the separator 400 is compressed by the battery cell 100. When the separator 400 is compressed, the outer periphery of the separator 400 expands, so it is preferable that the size be smaller than the size of the battery cell 100. The thickness of the separator 400 in the first direction (Y direction) is preferably about 0.5 mm to 10 mm.

[0041] The main body 410 of the separator 400 is required to function primarily as a heat insulating material, and suitable materials include glass wool, rock wool, cellulose fiber, aerogel, a mixed molding material of an inorganic filler and a binder, and a mixture of inorganic fiber and inorganic powder.

[0042] In this embodiment, the embedded portions 420 of the separator 400 have a strip-like shape extending in the third direction (Z direction) when viewed from the first direction (Y direction), and the embedded portions 420 are arranged at predetermined intervals in the second direction (X direction). In this embodiment, the embedded portions 420 are provided flush with the front side (side shown in the figure) of the main body portion 410, and are also provided flush with the back side (opposite side shown in the figure).

[0043] The embedded portion 420 is primarily required to function as an elastic material, and suitable materials include silicone rubber, fluororubber, urethane rubber, natural rubber, styrene butadiene rubber, butyl rubber, ethylene propylene rubber (EPM, EPDM), butadiene rubber, isoprene rubber, and norbornene rubber.

[0044] Furthermore, when selecting materials for the main body portion 410 and the embedded portion 420, it is preferable to select a material for the embedded portion 420 that melts above a predetermined temperature, but for the main body portion 410 that does not melt above the predetermined temperature. Here, the predetermined temperature is assumed to be the temperature at which the battery cell 100 reaches a high temperature. A high temperature state is considered to be a temperature of 300 to 1000°C or higher, which may cause thermal runaway of the cell. EPDM (ethylene propylene diene rubber) can be selected for the embedded portion, and aerogel, etc. can be selected for the main body portion.

[0045] Next, a state in which the separator 400 is sandwiched between the battery cells 100 will be described with reference to Figures 6 and 7. Figure 6 is a schematic diagram showing the battery cell 100 in a normal state (first state), and Figure 7 is a schematic diagram showing the battery cell 100 in an expanded state (second state). For ease of explanation, Figures 6 and 7 show a state in which one separator 400 is sandwiched between two battery cells 100.

[0046] As shown in Fig. 6, when the battery cell 100 is not expanded, there is no change in the separator 400. As shown in Fig. 7, when the battery cell 100 is expanded, the embedded portion 420 is more elastic than the main body portion 410, so the battery cell 100 expands toward the through-hole 420h. As a result, even if the battery cell 100 expands, the separator 400 can absorb the expansion of the battery cell 100.

[0047] Even if the embedded portion 420 melts and disappears due to heat generated by the battery cell 100, the main body portion 410 remains, and therefore the main body portion 410 can support the load generated by the expansion of the battery cell 100. Therefore, it is advisable to design the total required area of the side surfaces of the main body portion 410 facing the battery cell 100 taking into account the possibility that the embedded portion 420 will disappear.

[0048] (Relationship between deformation amount of battery cell 100 and diameter of through-hole 420h) Next, the relationship between the deformation amount of the battery cell 100 and the diameter of the through hole 420h will be considered with reference to Figures 8 to 10. Here, the maximum diameter of the through hole 420h in the first embodiment refers to the diameter in the second direction (X direction) rather than the third direction (Z direction). Figures 8 and 9 are first and second schematic cross-sectional views showing the relationship between the deformation amount of the battery cell and the diameter of the through hole, and Figure 10 is a diagram showing the relationship between the diameter of the through hole 420h and the deformation amount of the battery cell.

[0049] A case where the relationship between the deformation amount of the battery cell 100 and the hole diameter (D1) of the through-hole 420h is appropriate will be described with reference to Fig. 8. In the state shown in Fig. 8, even if the battery cell 100 expands toward the through-hole 420h, the expanded portion of the battery cell 100 does not come into contact with the opposing battery cell 100. In this way, even if the battery cell 100 expands, it does not come into contact with the opposing battery cell 100, making it possible to prevent a decrease in thermal resistance. Even if the embedded portion 420 disappears, the space of the through-hole 420h remains, making it possible to prevent heat transfer to the opposing battery cell.

[0050] A case where the relationship between the deformation amount of the battery cell 100 and the hole diameter (D2) of the through-hole 420h is inappropriate will be described with reference to Fig. 9. In the state shown in Fig. 9, the battery cell 100 expands toward the through-hole 420h, and the expanded portion of the battery cell 100 comes into contact with the opposing battery cell 100. When the battery cell 100 expands and comes into contact with the opposing battery cell 100 in this way, the thermal resistance decreases, heat is transferred directly to the opposing battery cell 100, and the opposing battery cell 100 is adversely affected by the heat.

[0051] Here, with reference to FIG. 10, the relationship between the through-hole 420h and the deformation amount of the battery cell 100 will be described. The inner diameter of the through-hole in the following description refers to the distance between one inner wall surface of the through-hole and another inner wall surface located in a perpendicular direction to the inner wall surface of the through-hole. Here, the case 120 of the battery cell 100 is an aluminum can with a thickness of 1 mm, and the gas release valve 130 operates at 1 MPa. Therefore, the internal pressure of the battery cell 100 is 1 MPa. The through-hole 420h was shaped in two shapes: a square (indicated by a square in the figure) and a round (indicated by a circle in the figure) for verification. As shown in FIGS. 8 and 9, the deformation amount of the battery cell 100 was measured based on the contact surface (S) between the battery cell 100 and the separator 400, and the amount of bulging from this contact surface (S) was defined as the deformation amount (α) mm.

[0052] As shown in Figure 10, increasing the inner diameter (mm) of the through-hole increases the deformation amount (α) of the battery cell 100. As the thickness of the separator 400 increases, the number of battery cells 100 that can be mounted in the battery module 1 decreases, resulting in a decrease in energy density. Therefore, a thickness of 10 mm or less is preferable. Therefore, the deformation amount (α) mm of the battery cell 100 is preferably 9 mm or less in order to avoid contact with the opposing battery cell 100.

[0053] As a result, it is preferable that the inner diameter of the through hole 420h is 60 mm or less. The shapes of the through hole 420h used were square (□ in the figure) and round (◯ in the figure), but either shape resulted in the same deformation amount (α) mm.

[0054] When the battery cells 100 deform, the rigidity of the case 120 decreases at high temperatures, and the increased load compresses the main body 410, causing the distance between the battery cells 100 to become shorter than expected. Considering this, it is preferable that the inner diameter of the through hole 420h be 30 mm or less in order to keep the deformation amount (α) of the battery cells 100 to 1 mm or less.

[0055] Furthermore, if the embedded portion 420 does not disappear completely but decreases in volume, in order to create a gap between the embedded portion 420 and the battery cell 100 and increase the insulating effect, it is more preferable that the inner diameter of the through hole 420h is 15 mm or less in order to make the deformation amount (α) mm 0.1 mm or less.

[0056] From the above, various shapes of through holes are possible, but it is preferable that the distance between one inner wall surface of the inner diameter of the through hole and another inner wall surface located perpendicular to the inner wall surface at the shortest point is 60 mm or less.

[0057] The following describes variations of the above-described embodiment 1. In the following embodiments, the configuration of the separator will be mentioned, and since the configurations of the battery module 1 and the battery cells 100 are basically the same, redundant description will not be repeated.

[0058] (Embodiment 2) Separator 400A according to the second embodiment will be described with reference to Fig. 11. Fig. 11 is a cross-sectional view showing the configuration of separator 400A, and corresponds to a cross section taken along line VV in Fig. 4.

[0059] In separator 400A of the present embodiment, embedded portion 420 protrudes (by length d) from the surface of main body portion 410 in the first direction (Y direction). Therefore, the length of embedded portion 420 in the first direction (Y direction) is longer than that of main body portion 410. In this way, separator 400A in which embedded portion 420 protrudes (by length d) from the surface of main body portion 410 can also achieve the same effects as those of the first embodiment.

[0060] Furthermore, the larger the protrusion, the larger the elastic width of the embedded portion 420 can be, which increases the effect of cushioning the reaction force of the battery cell 100. This allows the strength of restraining members such as the end plate 200 to be reduced, resulting in a lighter module. Also, by changing the size of the through-holes in the separator, the size of the embedded portion can be changed, making it possible to change the elasticity within the separator. As a result, the elasticity within the separator can be changed in different locations in accordance with the expansion of the battery cell.

[0061] (Embodiment 3) Separator 400B according to the third embodiment will be described with reference to Fig. 12. Fig. 12 is a cross-sectional view showing the configuration of separator 400B, and corresponds to a cross section taken along line VV in Fig. 4.

[0062] In the present embodiment, separator 400B is entirely covered with laminate film 430. Examples of laminate film 430 include PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), PVC (polyvinyl chloride), and PO (polyolefin).

[0063] Separator 400B whose entire periphery is covered with laminate film 430 in this manner can also provide the same effects as those of the above-described embodiment 1. Furthermore, because separator 400B is covered with laminate film 430, it is possible to prevent the embedded portion from coming off the main body portion during processes such as module assembly.

[0064] (Fourth embodiment) Separator 400C according to the fourth embodiment will be described with reference to Fig. 13. Fig. 13 is a side view of separator 400C as viewed from the first direction (Y direction).

[0065] The separator 400C in this embodiment has a main body portion 410C and a plurality of embedded portions 420C. Each embedded portion 420C has a cross shape and includes a first region 420C1 extending in a second direction (X direction) and a second region 420C2 extending in a third direction (Z direction). In this embodiment, the embedded portions 420C are arranged in two rows and five columns, but the number of embedded portions 420C is not limited to this. The embedded portions 420C may also be arranged in a staggered pattern.

[0066] The 400C having such a configuration can also achieve the same effects as those of the first embodiment. Furthermore, by lengthening the sides of the embedded portion, the embedding strength in the main body is increased, preventing disengagement. Furthermore, the diameter of the embedded portion can be reduced, preventing contact with the opposing battery cell when the cell expands.

[0067] (Embodiment 5) Separator 400D according to the fifth embodiment will be described with reference to Fig. 14. Fig. 14 is a side view of separator 400D as viewed from the first direction (Y direction).

[0068] The separator 400D of this embodiment has a main body portion 410D and an embedded portion 420D. The embedded portion 420D has a cross shape defined by the main body portion 410D, a first region 420D1 extending in the second direction (X direction), and a second region 420D2 extending in the third direction (Z direction), and the second regions 420D2 of the embedded portions 420D located above and below are connected to each other. Furthermore, a single third region 420D3 extending in the second direction (X direction) penetrates through the center of the second regions 420D2 that are connected to each other above and below.

[0069] The 400D having such a configuration can also achieve the same effects as those of the first embodiment. Furthermore, as in the fourth embodiment, the increased embedding strength in the main body portion prevents disengagement, and the diameter of the embedded portion can be reduced, preventing contact with the opposing battery cell during cell expansion. Furthermore, the multiple first regions 420D1 and second regions 420D2 are connected by the third region 420D3, forming the embedded portion 420D as an integrated component. Furthermore, the through-holes corresponding to the embedded portions 420D form an integrated through-hole, simplifying the assembly process for the embedded portion and the main body portion.

[0070] (Sixth embodiment) Separator 400E according to the sixth embodiment will be described with reference to Fig. 15. Fig. 15 is a side view of separator 400E as viewed from the first direction (Y direction).

[0071] The separator 400E in this embodiment has a main body portion 410E and a plurality of embedded portions 420E. Each embedded portion 420E is solid and has an elliptical shape with its major axis in the third direction (Z direction). In this embodiment, the embedded portions 420E are arranged in 2 rows and 7 columns, but the number of embedded portions 420E is not limited to this. The embedded portions 420E may also be arranged in a staggered pattern. The major axis direction of the ellipse is not limited to the third direction (Z direction) and may be oriented in any direction.

[0072] The 400E having such a configuration can also achieve the same effects as those of the first embodiment.

[0073] (Embodiment 7) Separator 400F according to the seventh embodiment will be described with reference to Fig. 16. Fig. 16 is a side view of separator 400F as viewed from the first direction (Y direction).

[0074] Separator 400F has a main body portion 410F and an embedded portion 420F. This embedded portion 420F has a hollow cylindrical shape. The arrangement and quantity can be 2 rows and 5 columns as shown in the fourth embodiment of FIG. 13, 2 rows and 7 columns as shown in the sixth embodiment of FIG. 15, or other numbers, a houndstooth check pattern, or various other arrangements.

[0075] Even with the 400F having such a configuration, it is possible to obtain the same effects as in the first embodiment. Furthermore, since the amount of resin is less in a hollow embedded portion than in a solid embedded portion, more space can be secured. Furthermore, even if the embedded portion melts, a space can be secured, ensuring thermal resistance to adjacent battery cells.

[0076] (Embodiment 8) A separator 400G according to the eighth embodiment will be described with reference to Fig. 17. Fig. 17 is a cross-sectional view of the separator 400G as viewed from the third direction (Z direction), and shows only one embedded portion 420G employed in the separator 400G.

[0077] Separator 400G in this embodiment has a main body portion 410G and multiple embedded portions 420G. Embedded portions 420G are solid and have a roughly barrel-shaped configuration with the outer diameter greatest at the center and decreasing toward both ends. The arrangement and quantity of embedded portions 420G can be 2 rows and 5 columns as shown in the fourth embodiment of FIG. 13, 2 rows and 7 columns as shown in the sixth embodiment of FIG. 15, or other numbers, such as a houndstooth pattern, or various other arrangements.

[0078] The 400G having such a configuration can also achieve the same effects as those of the first embodiment. Furthermore, since the protrusion in the X direction applies a load to the main body, a frictional force is generated between the main body and the embedded part. As a result, the bonding strength between the main body and the embedded part increases, making it possible to prevent the embedded part from coming off the main body during processing.

[0079] (Embodiment 9) The separator 400H according to the ninth embodiment will be described with reference to Fig. 18. Fig. 18 is a cross-sectional view of the separator 400H as viewed from the third direction (Z direction), and shows only one embedded portion 420H employed in the separator 400H.

[0080] The separator 400H of this embodiment has a main body 410H and multiple embedded portions 420H. The embedded portions 420H are solid and have the shape of a truncated cone whose outer diameter decreases from one end to the other. The arrangement and quantity of the embedded portions can be anything from the 2-row, 5-column arrangement shown in FIG. 13 for the fourth embodiment, or the 2-row, 7-column arrangement shown in FIG. 15 for the sixth embodiment, or any other number, such as a houndstooth pattern.

[0081] Even with 400H having such a configuration, the same effects as those of the first embodiment can be obtained. Furthermore, since one side is small, it is easy to install the embedded part in the main body. Moreover, since the other side is larger than the hole in the main body, the main body and the embedded part can be lightly press-fitted together to prevent them from coming off.

[0082] (Embodiment 10) A separator 400I according to the tenth embodiment will be described with reference to Fig. 19. Fig. 19 is a cross-sectional view of the separator 400I as viewed from the third direction (Z direction), and shows only one embedded portion 420I employed in the separator 400I.

[0083] The separator 400I of this embodiment has a main body 410I and multiple embedded portions 420I. The embedded portions 420I are hollow and have a generally hourglass-shaped configuration in which the outer diameter is smallest in the center and increases toward both ends. The arrangement and quantity of the embedded portions 420I can be 2 rows and 5 columns as shown in the fourth embodiment of FIG. 13, 2 rows and 7 columns as shown in the sixth embodiment of FIG. 15, or other numbers, a houndstooth pattern, or various other arrangements.

[0084] The 400G battery cell having such a configuration can also achieve the same effects as those of the first embodiment. Furthermore, when the embedded portion melts, a space is provided between adjacent battery cells, ensuring thermal resistance. In addition, the embedded portion is larger on the outer surface side of the main body portion than on the inner side, making it less likely to come off the main body portion. Furthermore, the embedded portions may be connected to each other by a flat base member that is thinner than the heat-resistant layer, and the individual embedded portions may be integrated. This makes it less likely for the embedded portions to come off during processing and simplifies the assembly of the embedded portions and the main body portion.

[0085] The separator variations shown in the second to tenth embodiments are based on the configuration of the first embodiment, but may be configured in a manner that does not presuppose the configuration of the first embodiment.

[0086] In each embodiment, separators arranged between multiple battery cells have been described, but a similar configuration to 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.

[0087] 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]

[0088] 1 battery module, 100 battery cell, 110 electrode terminal, 111 positive electrode terminal, 112 negative electrode terminal, 120 case, 121, 411 upper surface, 122, 412 lower surface, 123, 413 long side, 124, 414 short side, 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, 410C, 410D, 410E, 410F, 410G, 410H, 410I Main body portion, 420, 420C, 420D, 420E, 420F, 420G, 420H, 420I embedded portion, 420C1, 420D1 first region, 420C2, 420D2 second region, 420D3 third region, 420h through hole, 430 laminate film.

Claims

1. a plurality of battery cells arranged in a first direction; a separator sandwiched between the plurality of battery cells; Equipped with The separator is a main body; embedded portions embedded in the plurality of through holes provided in the main body portion; Including, The main body portion is a heat insulating material having better heat insulating performance than the buried portion, the embedded portion is made of an elastic material having higher elasticity than the main body portion, The distance between one inner wall surface of the inner diameter of the through hole and another inner wall surface located in a perpendicular direction to the one inner wall surface at a point where the distance is shortest is 60 mm or less. Battery module.

2. In the first direction, the length of the embedded portion is longer than the length of the main body portion. The battery module according to claim 1 .

3. The embedded portion melts at a temperature equal to or higher than a predetermined temperature, but the main body portion does not melt at a temperature equal to or higher than the predetermined temperature. The battery module according to claim 1 .

4. When viewed from the first direction, the embedded portion has a shape of a solid circle, a solid ellipse, a solid cross, a hollow circle, or a hollow ellipse. The battery module according to claim 1 .

5. When viewed from the first direction, the embedded portion has a shape including a first region extending in a second direction included in the imaginary plane and perpendicular to the first direction, and a second region extending in a third direction included in the imaginary plane and perpendicular to the second direction. The battery module according to claim 1 .

6. The separator is covered with a laminate film. The battery module according to claim 1 .

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