Battery module and method for manufacturing the battery module

Abstract

To suppress positional deviation of a battery stack without impairing insertability of the battery stack into a case.SOLUTION: A battery module comprises: a battery stack including a cell laminate and a pair of end plates; and a case for housing the battery stack. When an end plate-side end surface, which is an inclined surface, comes into contact with a case-side end surface, a binding load in a lamination direction is applied to the cell laminate. Each of the end plate has a recess which is formed so as to surround a portion of the end plate-side end surface. The case has a hole formed at a position facing, in the lamination direction, a region surrounded by the recess of the end plate. With the battery stack housed in the case, a contact surface, which is a portion of the end plate-side end surface to make contact with the case-side end surface, is pressed inward in the lamination direction from the case-side end surface. As a result, a region surrounded by the recess protrudes relatively further outward in the lamination direction than the contact surface so as to enter the inside of the hole.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 discloses a battery module in which a battery stack including a cell stack and end plates is housed in a case. In this battery module, a restraint load on the cell stack is generated by a contact structure between the end plates and the case. Specifically, the end faces of the end plates and the end faces of the case that face each other in the stacking direction are inclined surfaces, and the inclined surfaces come into contact with each other while the battery stack is compressed in the stacking direction, so that a restraint load is applied from the case to the cell stack. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-032519 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration described in Patent Document 1, sawtooth-like irregularities are formed on the end faces of the case and the end faces of the end plates to prevent the battery stack from moving upward along the end faces of the case as a result of misalignment of the battery stack. However, since it is not easy to fabricate a sawtooth structure, forming the sawtooth-like irregularities leads to increased costs. In addition, when the battery stack is inserted into the case, the end faces rub against each other while the battery stack is being inserted. This causes variations in the frictional force caused by the sawtooth-like irregularities, which may cause variations in the restraining load, and may cause parts of the sawtooth to fall off due to wear and become foreign matter.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a battery module that can suppress misalignment of a battery stack without impairing the ease of inserting the battery stack into a case. [Means for solving the problem]

[0006] The present invention provides a battery stack including a cell stack in which a plurality of battery cells are stacked in a thickness direction, and a pair of end plates arranged on both ends of the cell stack in a stacking direction, and a case that is open at the top and has an accommodation space in which the battery stack is accommodated, wherein the end plate has, as an outer end face in the stacking direction, an end plate side end face that is inclined so that a dimension of the battery stack in the stacking direction becomes smaller toward a lower end of the end plate, and the case has, as an inner end face in the stacking direction, a case side end face that is inclined so that a dimension of the accommodation space in the stacking direction becomes smaller toward the lower end of the case, and a battery module in which a restraining load in the stacking direction is applied to the cell stack by contact with the case side end face, wherein the end plate has a recess formed to surround a portion of the end plate side end face, and the case has a hole formed at a position opposite in the stacking direction to the area surrounded by the recess of the end plate, and when the battery stack is accommodated in the case, a contact surface of the end plate side end face that contacts the case side end face is pressed inward in the stacking direction from the case side end face, causing the area surrounded by the recess to protrude relatively further outward in the stacking direction than the contact surface and penetrate inside the hole.

[0007] According to this configuration, when the contact surface of the end plate side end face is pressed inward in the stacking direction from the case side end face, the area of ​​the end plate side end face surrounded by the recess protrudes relatively outward from the contact surface and enters the inside of the hole of the case. Therefore, a catch structure can be formed between the case and the end plate. This makes it possible to suppress misalignment of the battery stack without impairing the insertability of the battery stack into the case.

[0008] In addition, the recess may be a groove recessed inward in the stacking direction from the contact surface, the area surrounded by the groove including an end face that is inclined at the same angle as the contact surface in an unloaded state in which the contact surface is not pressed by the case side end face, and the hole may engage a structural part of the end plate including the area surrounded by the groove, thereby restricting upward movement of the battery stack.

[0009] According to this configuration, by providing the groove on the end face on the end plate side, it is possible to realize a catch structure in which the hole of the case engages with the structural part including the area surrounded by the groove.

[0010] The end plate may have a flat base portion arranged on a plane perpendicular to the stacking direction, and a rib protruding from the base portion outward in the stacking direction, the rib having a first rib whose outer end face in the stacking direction forms the contact surface, and a second rib which is not pressed by the case side end face and is a structural part of an area surrounded by the recess, the recess being a depression in the stacking direction into the base portion relative to the outer end face in the stacking direction of the second rib, and the hole portion may engage the second rib and restrict upward movement of the battery stack.

[0011] According to this configuration, the rib provided on the end plate can provide a catch structure in which the hole in the case engages with the second rib of the end plate.

[0012] The second rib may include a reinforcing rib that receives a load input from above and below.

[0013] According to this configuration, when the second rib is engaged with the hole, the reinforcing rib receives a load in the vertical direction, and therefore the second rib can withstand the load input in the vertical direction.

[0014] Moreover, the contact surface may be formed by an elastic body integrated with the first rib.

[0015] According to this configuration, the contact surface of the end face on the end plate side is formed of an elastic body, so that the elastic body is deformed and the second rib can be caused to protrude relatively further outward in the stacking direction.

[0016] In addition, the hole may be located below the vertical center of the storage space and at the widthwise center of the battery cell, and may have a rectangular opening whose opening width in the width direction is longer than the opening width in the vertical direction.

[0017] According to this configuration, the hole is shaped like a rectangle that is wide in the width direction of the case, and the hole is located at the center of the width direction of the battery cell, which reduces the moment that occurs when the battery stack receives an upward force and tries to move. Also, since the hole is located below the center of the storage space in the vertical direction, the deformation of the side end face of the case is small, and the compressive force in the stacking direction is likely to be strong. This makes it easier for the end plate to protrude, making it easier to mechanically catch with the case. Effect of the Invention

[0018] In the present invention, when the contact surface of the end plate side end face is pressed inward in the stacking direction from the case side end face, the area of ​​the end plate side end face surrounded by the recess protrudes relatively outward beyond the contact surface and enters the inside of the hole of the case. Therefore, a catch structure can be formed between the case and the end plate. This makes it possible to suppress misalignment of the battery stack without impairing the insertability of the battery stack into the case. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram illustrating a battery module according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing the state before the battery stack is assembled into the case. [Diagram 3] FIG. 3 is a diagram showing an outer end face of an end plate in the stacking direction. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA of FIG. [Diagram 5] FIG. 5 is a diagram for explaining the insertion step. [Figure 6] FIG. 6 is a diagram showing the no-load state. [Figure 7] FIG. 7 is a diagram showing a load application state. [Figure 8] FIG. 8 is a diagram showing a schematic structure of the comparative example. [Figure 9] FIG. 9 is a diagram illustrating a battery module according to a modified example. [Figure 10] FIG. 10 is a diagram for explaining the structure of the case. [Figure 11] FIG. 11 is a diagram for explaining an end plate according to a modified example. [Figure 12] FIG. 12 is a diagram showing a schematic structure of an end plate according to a modified example. [Figure 13] FIG. 13 is a diagram for explaining the relationship with a machine-side tool. [Figure 14] FIG. 14 is a diagram for explaining an end plate according to a further modified example. [Figure 15] FIG. 15 is a diagram showing a schematic structure of an end plate according to a further modified example. [Figure 16] FIG. 16 is a cross-sectional view taken along line HH in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, a battery module according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiment described below.

[0021] Fig. 1 is a diagram showing a battery module according to an embodiment of the present invention, and Fig. 2 is a diagram showing a state before a battery stack is assembled into a case.

[0022] The battery module 1 includes a battery stack 2 and a case 3 that houses the battery stack 2.

[0023] The battery stack 2 includes a cell stack 4 and a pair of end plates 5 arranged on either side of the cell stack 4 in the stacking direction. The battery stack 2 is a stack made up of the cell stack 4 and the end plates 5. The battery stack 2 is used in a state where a compressive load is applied in the stacking direction. The stacking direction of the cell stack 4 is simply referred to as the stacking direction, and when explaining the configuration other than the cell stack 4, the direction parallel to the stacking direction is also referred to as the stacking direction.

[0024] The cell stack 4 includes battery cells 6 and separators 7. The cell stack 4 is a stack made up of battery cells 6 and separators 7. The cell stack 4 has a structure in which a plurality of battery cells 6 and a plurality of separators 7 are alternately stacked in the thickness direction. Between the battery cells 6, plate-shaped separators 7 are arranged to serve as insulating layers.

[0025] The battery cells 6 are secondary batteries that can be charged and discharged. For example, the battery cells 6 are lithium ion secondary batteries or sodium ion secondary batteries. The battery cells 6 include those whose exterior is an aluminum can or laminated packaging. For example, the battery cells 6 are prismatic batteries in which the electrode body is housed in a flattened rectangular parallelepiped cell case, and a positive electrode terminal and a negative electrode terminal protrude from the upper end surface of the battery cell 6. Of the outer surfaces of the battery cell 6, the surface facing the stacking direction is referred to as the surface of the battery cell 6.

[0026] The separator 7 is a plate-like member made of resin and is made of an insulating material. The separator 7 made of resin can expand and contract in the stacking direction. In other words, the battery stack 2 is a laminate having the separator 7 made of resin, and therefore is an expandable body having a spring constant in the stacking direction.

[0027] A pair of end plates 5 are arranged on both sides in the stacking direction of the cell stack 4, which is made up of these battery cells 6 and separators 7. The pair of end plates 5 sandwich the cell stack 4 from both sides in the stacking direction, and are configured to be able to apply a restraining load, which is a compressive force in the stacking direction, to the battery cells 6.

[0028] The end plate 5 is a plate-like member made of a metal such as aluminum or resin. The end plate 5 has an end plate side end face 8 formed to face outward in the stacking direction as an end face of the battery stack 2. The surface of the end plate 5 opposite the end plate side end face 8 is formed in a plane perpendicular to the stacking direction (a vertical surface extending in the up-down direction).

[0029] The end plate side end face 8 is an outer end face in the stacking direction, and faces an inner end face of the case 3 in the stacking direction. The end plate side end face 8 is formed as an inclined surface that inclines so that the dimension of the battery stack 2 in the stacking direction decreases toward the lower end of the end plate 5. This gives the battery stack 2 a structure in which the dimension in the stacking direction decreases toward the lower end of the battery stack 2. This structure is for applying an appropriate restraining load from the case 3 to the cell stack 4 when the battery stack 2 is accommodated in the accommodation space 9 of the case 3.

[0030] The case 3 is a structural member for applying a compressive load (constraint load) to the battery stack 2. The case 3 is a box-shaped member made of a material mainly composed of a metal such as aluminum.

[0031] 2, the case 3 has an accommodation space 9 for accommodating the battery stack 2. The accommodation space 9 is a space that is open at the top, and the battery stack 2 can be inserted through this upper opening. The case 3 also has, as an inner surface of the case 3, a case side end surface 10 that is formed to face inward in the stacking direction.

[0032] The case side end face 10 is an inner end face of the case 3, and faces the end plate side end face 8 in the stacking direction. The case side end face 10 is formed as an inclined surface that inclines so that the dimension of the storage space 9 in the stacking direction decreases toward the bottom end of the case 3. In other words, the case side end face 10 forms the outer end face of the storage space 9 in the stacking direction, and is inclined so that the length of the storage space 9 in the stacking direction decreases. The inclination angle of the case side end face 10 is set to the same angle as the inclination angle of the end plate side end face 8.

[0033] Furthermore, the battery module 1 has a structure (hereinafter referred to as a hooking structure) for mechanically hooking the battery stack 2 to the case 3 as a structure for restricting the battery stack 2 from moving upward along the case side end face 10 when the battery stack 2 is housed in the housing space 9. The hooking structure is formed by the end plate 5 and the case 3, and includes a groove portion 11 provided in the end plate 5 and a hole portion 13 provided in the case 3.

[0034] As shown in Fig. 3, the end plate 5 has a groove portion 11 formed so as to surround a portion of the end plate side end face 8. The end plate side end face 8 is configured to include an area 12 surrounded by the groove portion 11 and an area not surrounded by the groove portion 11. The area 12 of the end plate side end face 8 surrounded by the groove portion 11 includes an end face that is inclined at the same inclination angle as the end plate side end face 8. The area of ​​the end plate side end face 8 not surrounded by the groove portion 11 is a surface facing the case side end face 10 in the stacking direction and is a contact surface that comes into contact with the case side end face 10.

[0035] Groove portion 11 is formed in a rectangular shape surrounding region 12 at a position that is the widthwise center and lower than the up-down center of end plate side end face 8. Groove portion 11 includes an upper groove extending linearly along the width direction on a relatively upper side, a lower groove extending linearly along the width direction on a relatively lower side, and widthwise end grooves extending linearly along the up-down direction to connect both widthwise end portions of the upper groove and lower groove.

[0036] As shown in FIG. 4, the groove 11 is formed in a shape recessed from the end plate side end face 8 toward the inside in the stacking direction. The depth of the groove 11 is formed to a certain degree deep in order to relatively increase the amount by which the region 12 protrudes outward in the stacking direction when the contact surface of the end plate side end face 8 is pressed. For example, the depth of the groove 11 can be set to a depth equal to or more than half the dimension in the stacking direction of the end plate 5 that forms the opening end of the groove 11. In addition, the bottoms of the grooves 11 are formed at the same position in the stacking direction. In other words, since the end plate side end face 8 is an inclined surface that is inclined with respect to the vertical direction, if the bottoms of the grooves 11 are formed at the same position in the stacking direction, the grooves 11 are not formed to the same depth as a whole. In this case, the upper groove of the groove 11 is formed deeper than the lower groove of the groove 11. Furthermore, the depths of both widthwise end grooves of the groove 11 change along the vertical direction.

[0037] As shown in Fig. 5, the case 3 has a hole 13 provided at a position corresponding to the region 12 surrounded by the groove 11. The hole 13 is a hole formed in the case side end face 10, and is formed at a position facing the region 12 of the end plate 5 in the stacking direction. The hole 13 has an opening 13a facing the region 12 of the end plate 5 in the stacking direction. The opening 13a is formed in a quadrangle shape corresponding to the shape of the region 12 shown in Fig. 3. The hole 13 is formed, for example, by a through hole that penetrates the case 3 in the stacking direction.

[0038] 2, before the battery stack 2 is assembled into the case 3, the stacking direction length D1 of the lower end of the battery stack 2 in the no-load state is longer than the stacking direction length D2 of the lower end of the accommodation space 9 (D1>D2). Furthermore, the stacking direction length D1 of the lower end of the battery stack 2 in the no-load state is longer than the stacking direction length D3 of the upper end of the accommodation space 9 (D1>D3). The stacking direction length D3 of the upper end of the accommodation space 9 is longer than the stacking direction length D2 of the lower end of the accommodation space 9. Therefore, in the battery module 1, after the battery stack 2 consisting of the cell stack 4 and a pair of end plates 5 is constructed, the battery stack 2 is compressed in the stacking direction and inserted into the case 3.

[0039] When the battery stack 2 is assembled into the case 3 from the state shown in FIG. 2, the battery stack 2 is inserted into the accommodation space 9 from the top of the accommodation space 9.

[0040] Here, the steps performed when assembling the battery stack 2 into the case 3 will be described. First, in the insertion step, as shown in FIG. 5, the battery stack 2 is inserted into the case 3 while being compressed in the stacking direction. In this inserted state, the end plate side end face 8 is not in contact with the case side end face 10. For example, the battery stack 2 is compressed in the stacking direction using an insertion tool or the like. The battery stack 2 in the compressed state by the tool or the like is inserted from the top of the accommodation space 9. Then, in the state where the lower end of the battery stack 2 is in contact with the bottom surface of the case 3 (insertion step), a compressive force from the tool is acting on the battery stack 2, and a gap G1 is provided between the end plate side end face 8 and the case side end face 10.

[0041] In this insertion step, the insertion tool can apply a compressive force in the stacking direction to the battery stack 2 without pressing the end plate side end face 8. Therefore, in the insertion step, the end plate 5 is kept in an unloaded state.

[0042] The unloaded state refers to the state of the end plate 5, and refers to a state in which no compressive force in the stacking direction is acting on the end plate side end face 8. Specifically, as shown in FIG. 2, in the battery stack 2 in an uncompressed state, the end plate 5 is in an unloaded state. Also, in the insertion process, even if the battery stack 2 is in a compressed state in the stacking direction, if no compressive force in the stacking direction is acting on the end plate side end face 8, the end plate 5 is in an unloaded state. That is, in the insertion process, as shown in FIG. 5, if the end plate side end face 8 is separated from the case side end face 10, the end plate 5 is in an unloaded state. Similarly, in the insertion process, in a state in which a compressive force in the stacking direction by the tool is acting on the battery stack 2, as shown in FIG. 6, even if the end plate side end face 8 is in contact with the case side end face 10, if the end plate side end face 8 is not pressed by the case side end face 10, the end plate 5 is in an unloaded state.

[0043] When the insertion step is completed, a step of removing the insertion tool etc. is performed. When the insertion tool etc. is removed in this step, the end plate 5 transitions from an unloaded state to a loaded state. When the battery stack 2 is accommodated in the accommodation space 9, the end plate side end face 8 comes into contact with the case side end face 10, compressing the battery stack 2 in the stacking direction and applying a restraining load from the case 3 to the battery stack 2.

[0044] A restraint load is applied from the case 3 to the battery stack 2, which applies pressure to the surfaces of the battery cells 6 and restricts and restrains the mutual movement of the multiple battery cells 6 and separators 7 that make up the cell stack 4. To obtain this restraint load, in the battery module 1, the end faces in the stacking direction of the battery stack 2 and the storage space 9 are inclined surfaces. Due to this inclined surface, the case side end face 10 functions as a restraint surface, making it possible to apply an appropriate restraint load to the cell stack 4.

[0045] Specifically, after the battery stack 2 is inserted into the case 3, a portion of the end plate side end face 8 that contacts the case side end face 10 receives a load F from the case side end face 10 as shown in FIG. 7. The load F is a force that acts inward in the stacking direction from the case side end face 10 to the end plate side end face 8. Therefore, the state shown in FIG. 7 is a state in which the end plate side end face 8 receives a compressive force (constraint load) in the stacking direction from the case side end face 10. In this case, the end plate 5 is in a load-applied state. As a result, the battery stack 2 is compressed in the stacking direction by the constraint load applied from the case side end face 10 to the end plate side end face 8.

[0046] In this load-applied state, the portion of the end plate side end face 8 that contacts the case side end face 10 receives the load F, causing the battery stack 2 to undergo compressive deformation in the stacking direction. The battery stack 2 receives a restraining load whose magnitude is the deformation amount multiplied by the spring constant. Thus, pressure is applied evenly to the surfaces of the multiple battery cells 6 included in the battery stack 2.

[0047] Furthermore, in the load-applied state, the region 12 of the end plate side end face 8 surrounded by the groove portion 11 does not receive the load F. The region 12 surrounded by the groove portion 11 does not receive the load F to begin with, and the amount of deformation is small. The groove portion 11 separates a portion that receives the load F (contact surface) from a portion that does not receive the load F (region 12). With this structure, when the contact surface of the end plate side end face 8 of the end plate 5 receives the load F, the portion having the contact surface as the end face is compressed and deformed inward in the stacking direction. In contrast, because of the structure having the groove portion 11, region 12 is less susceptible to the influence of the surrounding region receiving the load F even in the load-applied state, and in the load-applied state, region 12 protrudes relatively outward in the stacking direction from the contact surface.

[0048] As shown in Fig. 7, in a load-applied state in which the battery stack 2 is housed in the case 3, the contact surface of the end plate side end surface 8 that contacts the case side end surface 10 is pressed inward in the stacking direction from the case side end surface 10, causing the region 12 surrounded by the groove portion 11 to protrude relatively outward in the stacking direction from the contact surface and enter the hole portion 13. In contrast, in a no-load state, as shown in Fig. 6, the region 12 surrounded by the groove portion 11 does not protrude relatively and does not enter the hole portion 13.

[0049] The structural part including the region 12 of the end plate 5 enters the inside of the hole 13 of the case 3, and the hook structure is activated. The hole 13 locks the structural part including the region 12 and restricts the upward movement of the battery stack 2. The structural part including the region 12 surrounded by the groove 11 functions as a protrusion of the end plate 5. The hole 13 is for hooking the protrusion of the end plate 5 and restricting the upward and downward movement of the battery stack 2. Since the case side end face 10, which is the restraining surface, is an inclined surface, a force acts in a direction in which the battery stack 2 shifts upward along the case side end face 10, together with the restraining load, which is a compressive force in the stacking direction. Therefore, a hook is created between the case 3 and the end plate 5, and the battery stack 2 is mechanically held. The case 3 and the end plate 5 form a hook structure, which can restrict the upward movement of the battery stack 2.

[0050] Furthermore, the insertion tool used in the insertion step is capable of applying a compressive force in the stacking direction to the battery stack 2 while in contact with a portion of the battery stack 2 other than the end plate side end face 8, without pressing the end plate side end face 8. Therefore, on the end plate side end face 8, the area 12 surrounded by the groove 11 and the area not surrounded by the groove 11 are located on the same plane. That is, in the battery module 1 of the embodiment shown in FIG. 5, the gap G1 can be made small.

[0051] 8, if end plates 105 constituting a battery stack 102 have a structure having a convex portion 101 protruding outward in the stacking direction from an end plate side end face 108, it is necessary to provide a gap G2 between the end plate side end face 108 and the case side end face 10 as a gap equal to or larger than the protrusion amount of the convex portion 101. In this case, in order to provide the gap G2, the compression amount of the battery stack 2 in the insertion process must be increased.

[0052] In contrast, in the battery module 1 of the embodiment shown in Figure 5, in the unloaded state during the insertion process, the entire end plate side end face 8 including the contact surface and area 12 is flat on the same plane (area 12 surrounded by groove portion 11 does not protrude relatively), so that the gap G1 between the case 3 and the battery stack 2 can be made smaller than the gap G2 when the battery module 100 of the comparative example is used.

[0053] As described above, according to the embodiment, only when a load is applied from the case 3 to the battery stack 2, the structural portion including the region 12 surrounded by the groove portion 11 on the end plate side end face 8 protrudes relatively outward in the stacking direction, and the catch structure functions. This makes it possible to suppress displacement of the battery stack 2 without impairing ease of insertion when inserting the battery stack 2 into the case 3.

[0054] Moreover, the simple structure consisting of the groove 11 provided in the end plate 5 and the hole 13 provided in the case 3 can realize the hooking structure.

[0055] The depth of hole 13 is not particularly limited as long as it is recessed outward in the stacking direction relative to case side end face 10. That is, hole 13 may be a hole formed so that its bottom surface faces region 12, or may be a through hole penetrating case 3 along the stacking direction.

[0056] Moreover, a battery module 1 in a modified example will be described with reference to FIGS.

[0057] As shown in FIG. 9, in the battery module 1 of the modified example, the battery stack 2 is configured by a laminated body made up of a cell laminate 4 and a pair of end plates 20, and the case 3 has a structure in which ribs 31 are provided on the outer wall thereof.

[0058] The case 3 has linear ribs 31 extending in the width direction on the outer surface of an outer wall portion provided on the outer side in the stacking direction. As shown in Fig. 10, three ribs 31 are provided at different positions in the vertical direction. For example, on one outer wall portion of the case 3, two ribs 31 are provided at a position above the center position B in the vertical direction, and one rib 31 is provided at a position below the center position B in the vertical direction.

[0059] 10, hole 13 has a rectangular shape with rounded corners. Hole 13 has a rectangular opening whose width is longer than its vertical opening. By making hole 13 rectangular in shape, the moment that tends to rotate battery stack 2 can be reduced.

[0060] The hole 13 is located at a position C below the central position B in the vertical direction and at the central position E in the width direction. By providing the hole 13 at the central position E in the width direction of the case 3, it is possible to reduce the moment that occurs when the battery stack 2 receives an upward force and tries to move upward. Furthermore, the deformation of the case side end face 10 is smaller in the lower part of the case 3 than in the upper part of the case 3 due to the effect of the member provided on the bottom surface of the case 3. Therefore, the compressive force in the stacking direction is likely to be strong in the lower part of the case 3. Therefore, the end plate 5 is likely to protrude and become easily caught. In short, it is suitable as a position for providing a catch structure.

[0061] Furthermore, since it is difficult to create hole 13 if it is deep, hole 13 is arranged to avoid rib 31 provided to increase the rigidity of case 3. In other words, a configuration is adopted in which rib 31 is not arranged at the position where hole 13 is provided. When case 3 is assumed to be an aluminum casting, it is assumed that hole 13 is created using a mold, and hole 13 is configured as a through hole.

[0062] As shown in FIG. 11, the end plate 20 has a flat base portion 21, a rib 22 protruding outward in the stacking direction from the base portion 21, and an end plate side end face 23 which is the outer end face of the rib 22 in the stacking direction.

[0063] 12, the end plate 20 has a locking rib 24 formed at a position corresponding to the hole 13 of the case 3. The locking rib 24 is like a small island, independent of the other ribs 22. In the end plate 20, the rib 22 serves as a first rib, and the rib 24 serves as a second rib.

[0064] Further, the end plate 20 has an end face 25 on the outer side in the stacking direction of the locking rib 24. This locking rib 24 is surrounded by a recess in the base portion 21 from the outer end face 25 in the stacking direction. In other words, the end face 25 is an area surrounded by a recess recessed from the end face 25 into the base portion 21.

[0065] Furthermore, the end plate 20 is provided with a reinforcing rib 26 extending vertically inside so that the portion corresponding to the hole 13 of the case 3 can withstand a load in the vertical direction. That is, the locking rib 24 is a rectangular rib extending linearly in the vertical and width directions, and the reinforcing rib 26 extending linearly in the vertical direction is provided inside the rib 24.

[0066] As shown in FIG. 13 , a rib 22 is provided as a contact surface with the case side end face 10 to avoid the claw portion 41 of the machine side tool 40 so that the battery stack 2 can be inserted while being compressed before being accommodated in the case 3.

[0067] Further, a battery module 1 according to a further modified example will be described with reference to FIGS.

[0068] 14 to 16, a battery module 1 according to a further modified example has a structure in which an elastic body 27 such as rubber is provided on the outer end face in the stacking direction of the end plate 5. The elastic body 27 is integrated with the tip end portion in the stacking direction of the rib 22. The outer end face in the stacking direction of the elastic body 27 forms an end plate side end face 28.

[0069] In order to reduce restraint load fluctuations of the battery stack 2 in response to load fluctuation factors, some of the components of the battery stack 2 include elastic bodies 27, which are easily deformed members. By forming the end plate side end faces 28 with the elastic bodies 27, the ribs 24 can be made to protrude further, and the engagement with the case 3 can be strengthened. By providing the member on which the elastic bodies 27 are provided on the end plate 5 side, the amount of elastic body 27 can be reduced to a minimum. Furthermore, compared to a structure in which a sheet-shaped elastic member is inserted between the end plate 5 and the case 3, the number of parts can be reduced. [Explanation of symbols]

[0070] 1 Battery module 2 Battery stack 3 Cases 4 Cell stack 5 End Plate 6 Battery Cells 7 Separator 8 End plate side end face 9. Storage Space 10 Case side end face 11 Groove 12 areas 13 Hole 13a opening 20 End Plate 21 Base 22 Ribs 23 End plate side end face 24 Ribs 25 End face 26 Ribs 27 Elastic Body 28 End plate side end face

Claims

1. A battery stack including a cell stack in which a plurality of battery cells are stacked in a thickness direction, and a pair of end plates arranged on both ends of the cell stack in a stacking direction; a case having an opening at the top and an accommodation space for accommodating the battery stack; Equipped with the end plate has an end plate side end surface, which is an outer end surface in a stacking direction, that is inclined so that a dimension of the battery stack in the stacking direction becomes smaller as the end plate approaches a lower end of the end plate, the case has an inner end surface in the stacking direction that is inclined such that a dimension of the storage space in the stacking direction becomes smaller as the case approaches a lower end of the case, A battery module in which a restraint load in a stacking direction is applied to the cell stack by contacting the end plate side end surface and the case side end surface, The end plate has a recess formed to surround a portion of the end plate side end surface, the case has a hole formed at a position facing a region surrounded by the recess of the end plate in a stacking direction, a contact surface of the end plate side end surface that contacts the case side end surface is pressed inward in a stacking direction by the case side end surface, The area surrounded by the recessed portion protrudes outward in the stacking direction beyond the contact surface and penetrates into the hole portion. A battery module comprising:

2. The recess is a groove recessed inward in a stacking direction from the contact surface, the region surrounded by the groove portion includes an end surface that is inclined at the same angle as the contact surface in a no-load state in which the contact surface is not pressed by the case side end surface, The hole engages a structural portion of the end plate, the structural portion including a region surrounded by the groove, and prevents the battery stack from moving upward. The battery module according to claim 1 .

3. The end plate is A flat base portion disposed on a plane perpendicular to the stacking direction; a rib protruding outward in a stacking direction from the base portion, The rib is A first rib having an outer end surface in the stacking direction that serves as the contact surface; a second rib that is not pressed from the case side end surface and is a structural part of an area surrounded by the recess, the recess is a depression in the stacking direction of the base portion with respect to an end face of the second rib on an outer side in the stacking direction, The hole engages the second rib and restricts the battery stack from moving upward. The battery module according to claim 1 .

4. The second rib includes a reinforcing rib that receives a load input from above and below, The contact surface is formed of an elastic body integrated with the first rib. The battery module according to claim 3 .

5. The hole is disposed below the vertical center of the storage space and at the widthwise center of the battery cell, and has a rectangular opening whose width in the widthwise direction is longer than the vertical opening width. The battery module according to any one of claims 1 to 4.

6. A battery stack including a cell stack in which a plurality of battery cells are stacked in a thickness direction, and a pair of end plates arranged on both ends of the cell stack in a stacking direction; a case having an opening at the top and an accommodation space for accommodating the battery stack; Equipped with the end plate has an end plate side end surface, which is an outer end surface in a stacking direction, that is inclined so that a dimension of the battery stack in the stacking direction becomes smaller as the end plate approaches a lower end of the end plate, the case has an inner end surface in the stacking direction that is inclined such that a dimension of the storage space in the stacking direction becomes smaller as the case approaches a lower end of the case, A method for manufacturing a battery module, in which a restraint load in a stacking direction is applied to the cell stack by contacting the end plate side end surface with the case side end surface, an insertion step of inserting the battery stack into the case while being compressed in a stacking direction, The end plate has a recess formed to surround a portion of the end plate side end surface, the case has a hole formed at a position facing a region surrounded by the recess of the end plate in a stacking direction, In the insertion step, when the battery stack is housed in the case, a contact surface of the end plate side end surface that contacts the case side end surface is pressed inward in the stacking direction from the case side end surface, so that a region surrounded by the recess protrudes relatively outward in the stacking direction beyond the contact surface and enters inside the hole portion. A method for manufacturing a battery module comprising the steps of:

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