Battery module and method of manufacturing the same

Abstract

To solve the following problem: in conventional battery modules, a cooling efficiency of a battery cell disposed near a termination part of a duct among cooling efficiencies of battery cells included in a battery stack is low.SOLUTION: A battery module of the present invention includes: a battery stack 1a; and a battery case 10 including a battery stack storage section 15a storing the battery stack, a chamber 11a in which an inflow port of cooling air and a termination wall 14a blocking the cooling air are provided to face each other in a first direction Y and an opening surface is provided on a surface in contact with an inlet of a cooling air passage, and a pair of rails provided at both ends of the opening surface, along the first direction in which the chamber extends. When a direction from one of the pair of rails to another thereof is defined as a horizontal direction X, the battery stack 1a is stored in the battery stack storage section 15a such that a tilt of the battery stack 1a relative to the horizontal direction X increases from the termination wall 14a toward the inflow port.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a battery module in which a battery stack, for example, in which a plurality of battery cells and spacers are alternately stacked, is housed in a battery case, and to a method for manufacturing the same. [Background technology]

[0002] When constructing an assembled battery by combining a large number of non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries, a battery stack is formed by stacking a plurality of secondary batteries, and this battery stack is housed in a stack case. In addition, in the assembled battery, cooling air may be supplied into the stack case to cool each battery cell of the battery stack. In addition, when cooling with such cooling air is performed, a chamber is provided in the stack case, and cooling air is supplied to each battery cell through this chamber. Therefore, an example of a technology related to a spacer that cools the battery cells with cooling air supplied from the chamber is disclosed in Patent Document 1.

[0003] The battery pack described in Patent Document 1 is an assembled battery having a battery group in which a plurality of single cells are arranged and a first refrigerant passage is formed to conduct a refrigerant between adjacent cells in the arrangement direction, and the first refrigerant passage is formed with a plurality of first protrusions, and the first protrusions have a first arc-shaped portion that is convex toward the upstream side of the first refrigerant passage, and a pair of first tapered portions that extend from both ends of the first arc-shaped portion toward the downstream side of the first refrigerant passage and approach each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-93224 A Summary of the Invention [Problem to be solved by the invention]

[0005] The technology described in Patent Document 1 relates to the flow path shape of the refrigerant passage formed in the spacer. However, in a battery module in which a battery stack is housed in a battery case, a problem occurs in that pressure loss occurs when cooling air is diverted from the chamber to the cooling air flow path formed in the spacer. Patent Document 1 does not mention the decrease in cooling efficiency caused by the increase in this pressure loss, and there is a problem in that the increase in pressure loss of the cooling air diverted from the chamber to the cooling air flow path of the spacer cannot be solved.

[0006] The present invention has been made in consideration of the above circumstances, and aims to improve the cooling efficiency of battery cells included in a battery stack, especially those that are arranged near the end of a chamber. [Means for solving the problem]

[0007] One aspect of a battery module according to the present invention comprises a battery stack in which battery cells and spacers forming a cooling air flow path through which cooling air flows are alternately stacked, a battery stack storage section for storing the battery stack, and a battery case including: a chamber in which an inlet for the cooling air and an end wall for blocking the cooling air are arranged opposite each other in a first direction, the chamber having an opening surface on a surface adjacent to the inlet of the cooling air flow path, and a pair of rails arranged along the first direction in which the chamber extends at both ends of the opening surface, and when the direction from one of the pair of rails to the other is defined as the horizontal direction, the battery stack is stored in the battery stack storage section such that the inclination with respect to the horizontal direction increases from the end wall toward the inlet.

[0008] The manufacturing method of the battery module according to the present invention includes a battery stack in which battery cells and spacers having legs and a cooling air flow path through which cooling air flows are alternately stacked, a battery stack storage section for storing the battery stack, a chamber in which an inlet for the cooling air and a closing wall for blocking the cooling air are provided opposite each other in a first direction and an opening surface is provided on a surface that contacts the inlet of the cooling air flow path, a pair of rails provided along the first direction on both ends of the opening surface, and an end wall of the battery stack storage section in which a low-rigidity portion having a lower rigidity is provided on one side of the pair of rails in a horizontal direction from one side to the other side of the pair of rails than on the other side. a receiving jig is brought into contact with the end wall from the outside of the battery case, the battery stack is inserted into the battery stack storage section in a direction horizontal to the first direction so that the battery stack reaches the end wall, and after the battery stack reaches the end wall, a pressure is applied so that the battery stack presses the end wall further, thereby rotating the battery case, thereby increasing the amount of deviation of the legs relative to the rails from the closing wall toward the inlet, and storing the battery stack in the battery stack storage section so that the inclination of the battery stack with respect to the horizontal direction increases from the closing wall toward the inlet. Effect of the Invention

[0009] According to the secondary battery of the present invention, it is possible to improve the cooling efficiency of the battery cells arranged near the end portion of the chamber, among the battery cells included in the battery stack. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a battery stack according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram of a battery case according to the first embodiment. [Diagram 3] 5A and 5B are diagrams illustrating cooling airflow paths formed in the spacer according to the first embodiment. [Figure 4] FIG. 1 is a schematic diagram of a battery module according to a first embodiment. [Diagram 5] 5 is a diagram illustrating the flow of cooling air branching from a chamber to a spacer in the battery module according to the first embodiment. FIG. [Figure 6] FIG. 4 is a diagram illustrating a flow of cooling air in a chamber according to the first embodiment. [Figure 7] 2A to 2C are diagrams illustrating a manufacturing method of the battery module according to the first embodiment. [Figure 8] 5A and 5B are diagrams illustrating the amount of displacement of a battery cell relative to a battery case in the battery module according to the first embodiment. [Figure 9] FIG. 11 is a schematic diagram of a battery case according to a second embodiment. [Figure 10] 10A to 10C are diagrams illustrating a manufacturing method of a battery module according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In each drawing, the same elements are given the same reference numerals, and repeated explanations are omitted as necessary. In the following description, the direction in which the battery stacks are arranged in the battery case is defined as the horizontal direction X or width direction X, the direction from the inlet that allows cooling air to flow into the chamber toward the closing wall that blocks the cooling air is defined as the depth direction Y or first direction Y, and the direction perpendicular to the horizontal direction X and the depth direction Y and the height of the battery stack is defined as the vertical direction Z. In the following description, the horizontal direction X may be referred to as the left-right direction, and the vertical direction Z may be referred to as the up-down direction. In the following description, the combination of the battery stack and the battery case is referred to as the battery module.

[0012] First embodiment Fig. 1 shows a schematic diagram of a battery stack 1 according to the first embodiment. As shown in Fig. 1, the battery stack 1 according to the first embodiment has a plurality of battery cells 2 and spacers 3 stacked alternately. Here, the spacer 3 has a cooling air flow path formed therein through which cooling air supplied via a chamber, which will be described later, flows. Details of this cooling air flow path will be described above.

[0013] Next, a schematic diagram of the battery case 10 according to the first embodiment is shown in Fig. 2. The battery case 10 according to the first embodiment is, for example, a die-cast case formed by a casting method, but there is no particular limitation on the material. In the following explanation, a battery case capable of accommodating two battery stacks will be explained, but one battery case may accommodate one battery stack, or three or more battery stacks.

[0014] As shown in Fig. 2, the battery case 10 has a chamber, a pair of rails, a battery stack storage section, and an end wall. In the example shown in Fig. 2, the battery case 10 has two sets of these components corresponding to the number of battery stacks to be stored. Specifically, the battery case 10 has a first chamber 11a, a second chamber 11b, rails 12a, 12b, 13a, and 13b, a first end wall 14a, a second end wall 14b, a first battery stack storage section 15a, and a second battery stack storage section 15b.

[0015] The first battery stack storage section 15a is provided in an area covering the first chamber 11a, and stores the first battery stack 1a. The second battery stack storage section 15b is provided in an area covering the second chamber 11b, and stores the second battery stack 1b. The first chamber 11a and the second chamber 11b have openings on the surfaces (surfaces covered by the battery stack storage section in FIG. 2) that contact the inlets of the cooling air flow paths formed in the spacer 3. The rails 12a and 13a are provided at both ends of the openings along the first direction in which the first chamber 11a extends. The rails 12b and 13b are provided at both ends of the openings along the first direction in which the second chamber 11b extends.

[0016] In addition, an air guide tube 20 is provided on the side of the battery case 10 where the inlets of the first chamber 11a and the second chamber 11b are provided. The air guide tube 20 has an air outlet 21, and distributes the cooling air blown from the air outlet 21 to both the first chamber 11a and the second chamber 11b. The air outlet 21 may be provided with a blower for blowing the cooling air. Note that FIG. 2 illustrates a flow dividing structure 20a as a member for reducing pressure loss when the cooling air supplied from the air outlet 21 is branched. The flow dividing structure 20a has a shape that tapers toward the air outlet 21 side, and is provided as a part of the air guide tube 20.

[0017] In addition, the first end wall 14a and the second end wall 14b are provided at positions facing the inlets of the first chamber 11a and the second chamber 11b in the first direction Y. The first end wall 14a and the second end wall 14b also function as walls against which the battery stack is pressed when the battery stack is stored. The first end wall 14a and the second end wall 14b are provided with a low-rigidity portion (e.g., low-rigidity portion Ww) having a lower rigidity than the other side in the horizontal direction from one side (e.g., rail 13a) of the pair of rails toward the other side (e.g., rail 12a). In FIG. 2, the end wall having a higher rigidity than the low-rigidity portion Ww is marked with the symbol of a high-rigidity portion Ws. In the battery case 10 according to the first embodiment, the end wall is formed so that the wall thickness gradually becomes thinner from one side to the other side in the horizontal direction, and the portion where the wall thickness becomes relatively thinner is called the low-rigidity portion Ww, and the portion where the wall thickness becomes relatively thick is called the high-rigidity portion Ws. In addition, the low-rigidity portion Ww and the high-rigidity portion Ws have main functions in the assembly process of the battery module, which will be described in detail later. In addition, the low-rigidity portion Ww is preferably provided in a portion away from the center position of the battery case 10 in the horizontal direction X.

[0018] Next, the spacer 3 will be described in detail. Fig. 3 is a diagram illustrating a cooling air flow path formed in the spacer 3 according to the first embodiment. In Fig. 3, the spacer 3 and the battery case 10 are illustrated so that the structures of the battery case 10 and the spacer 3 when the battery stack 1 is inserted into the battery case 10 can be seen.

[0019] As shown in Fig. 3, the spacer 3 is provided with ribs 31, which define the shape of the flow path. The spacer 3 also has legs 32 and 33 at positions straddling the rails 12a and 13a. In the example shown in Fig. 3, a cooling air flow path is formed such that the side of the spacer 3 facing the chamber 11a serves as an inlet for the cooling air, and the side facing the side wall of the battery case 10 rising in the vertical direction Z serves as an outlet for the cooling air.

[0020] 3, rails 12a, 13a are preferably formed with a sloped side facing legs 32, 33. By making the side surface of the rail sloped, it becomes easier to control the amount of misalignment between the legs of spacer 3 and the rail of battery case 10 in the assembly process described below.

[0021] Next, the battery module after assembly will be described. FIG. 4 shows a schematic diagram of the battery module according to the first embodiment. As shown in FIG. 4, in the battery module according to the first embodiment, two battery stacks (a first battery stack 1a and a second battery stack 1b in FIG. 4) are stored in one battery case 10. In the battery module according to the first embodiment, the first battery stack 1a and the second battery stack 1b are stored in the battery case 10 at an offset angle with respect to the first direction Y. In addition, in the battery module according to the first embodiment, the battery cells 2 and the spacers 3 located on the inlet side of each chamber have an inclination θa (or an inclination θb) with respect to the horizontal direction X, while the battery cells 2 and the spacers 3 located on the end wall side of the chamber are stored so that their angle with respect to the horizontal direction Y is zero. That is, in the battery module according to the first embodiment, the battery stack is stored in the battery stack storage section so that the inclination with respect to the horizontal direction X increases from the end wall toward the inlet of the chamber.

[0022] As shown in FIG. 4, in the battery module according to the first embodiment, the first inclination θa of the first battery stack 1a and the second inclination θb of the second battery stack 1b are set to be linearly symmetrical with respect to the vertical direction Z as the axis of symmetry. Furthermore, in the battery module according to the first embodiment, the first inclination θa and the second inclination θb are set to open in a direction away from the axis of symmetry in the horizontal direction X. In the battery case 10, the cooling air supplied from the air outlet 21 is divided by the flow dividing structure 20a, so that the pressure tends to be high near the chamber on the outside of the horizontal direction X near the inlet of the chamber. By setting the first inclination θa and the second inclination θb in this way, the amount of change in pressure of the chamber shape can be increased along the side where high pressure occurs, so that it is possible to most effectively generate a vortex airflow on the end wall side. Details of this change in air pressure will be described later.

[0023] Here, the flow of cooling air flowing from the chamber to the spacer 3 side will be described for point A near the inlet of the chamber, point B near the center of the chamber, and point C near the end wall of the chamber in Fig. 4. In the following description, only the first chamber 11a side will be described, but the same air flow as the first chamber 11a occurs in the second chamber 11b, although the left and right directions are reversed. Therefore, Fig. 5 shows a diagram for explaining the flow of cooling air branching from the chamber to the spacer in the battery module according to the first embodiment. In Fig. 5, there are many arrows in the part where the wind pressure of the vortex air current is high, and the number of arrows decreases as the wind pressure of the vortex air current decreases.

[0024] As shown in FIG. 5, in the battery module according to the first embodiment, the vertical deviation between the leg of the spacer (e.g., leg 32) and one of the pair of rails (e.g., rail 12a) increases from the end wall toward the inlet of the chamber. As a result, in the first chamber 11a according to the first embodiment, the upper side of the first chamber 11a (e.g., the side where the inlet of the cooling air flow path of the spacer 3 is provided) is inclined, and this inclination becomes smaller in the depth direction Y of the chamber. In FIG. 5, HFr1, HFr2, and HFr3 are shown as the heights of points A, B, and C on the rail 12a side of the first chamber 11a, and Hrr1, Hrr2, and Hrr3 are shown as the heights of points A, B, and C on the rail 13a side of the first chamber 11a. In the battery module according to the first embodiment, the inclination of the battery stack is set so that the relationships HFr1>HFr2>HFr3, HFr3≒HRr3, and Hrr3≒HRr3≒HRr3 are satisfied.

[0025] In the battery module according to the first embodiment, a strong vortex airflow is generated in the portion closest to the inlet of the chamber due to the pressure difference between the left and right sides of the chamber caused by the branching of the cooling airflow supplied from the air outlet 21. This vortex airflow becomes smaller as it progresses in the depth direction Y of the first chamber 11a, but it also occurs near the end wall 14 (for example, point C) in the first chamber 11a because a pressure difference in the cooling airflow occurs between the left and right sides of the chamber due to a decrease in height, especially on the rail 12a side. This vortex airflow generates wind pressure in a direction that pushes the airflow up from the first chamber 11a toward the spacer 3, reducing the pressure loss of the cooling airflow.

[0026] 6 is a diagram for explaining the flow of cooling air in the chamber according to embodiment 1. In FIG. 6, the arrows indicating the airflow in the area where the cooling air pressure is high are thick, and the arrows become thinner as the air pressure decreases.

[0027] As shown in Fig. 6, in the battery module according to the first embodiment, the cooling air blown in from the air outlet 21 is separated by the airflow dividing structure 20a into a branched cooling air that flows into the first chamber 11a and a branched cooling air that flows into the second chamber 11b. At this time, near the airflow dividing structure 20a, that is, near the entrance of each chamber (for example, point A), the air pressure is high near the inside of the battery case 10 and low near the outside. Due to this difference in air pressure, a strong vortex airflow is generated near point A as shown in Fig. 5. This vortex airflow moves clockwise on the first chamber 11a side and counterclockwise on the second chamber 11b side.

[0028] The wind pressure of the cooling air decreases as it moves toward the end wall. At this time, even though the wind pressure is reduced, if the amount of cooling air flowing toward the spacer 3 decreases, the cooling air will turn back at the end wall, and this turning back of the cooling air will cause a swirling flow on the end wall side. However, in the battery module according to the first embodiment, even in the vicinity of the end wall, a vortex air current pushes the cooling air up toward the spacer 3, preventing the cooling air from turning back at the end wall. For this reason, in the battery module according to the first embodiment, it is possible to reduce the pressure loss of the cooling air even at the end wall.

[0029] Next, a manufacturing method of the battery module according to the first embodiment will be described. Fig. 7 shows a diagram for explaining the manufacturing method of the battery module according to the first embodiment. Note that, although Fig. 7 shows a process of storing the first battery stack 1a in the first battery stack storage section 15a, the second battery stack 1b can also be stored in the second battery stack storage section 15b through a similar process.

[0030] As shown in FIG. 7, in the manufacturing method of the battery module according to the first embodiment, a receiving jig 43 is brought into contact with the first end wall 14a from the outside of the battery case 10. Next, one end of the first battery stack 1a is pressed by a pressing jig 41 via a pressing plate 42, so that the first battery stack 1a is pressed into the first battery stack storage section 15a. At this time, the first battery stack 1a is pressed into the first end wall 14a so that the legs 32, 33 of the first battery stack are aligned with the rails 12a, 13a. As a result, the first battery stack 1a is inserted into the first battery stack storage section 15a in a direction horizontal to the first direction, and the first battery stack 1a reaches the first end wall 14a.

[0031] After that, the pressure is further increased by the pressure tool 41 so that the first battery stack 1a is pressed against the first end wall 14a. This pressure rotates the battery case 10 clockwise around the high rigidity portion Ws. This rotation of the battery case 10 increases the amount of deviation of the legs 32 from the rail 12a from the closing wall toward the inlet of the first chamber 11a. This rotation of the battery case 10 also increases the inclination of the battery stack from the closing wall toward the inlet of the first chamber 11a with respect to the horizontal direction. In this way, the first battery stack 1a is stored in the first battery stack storage section 15a.

[0032] Here, Fig. 8 shows a diagram for explaining the displacement amount of the battery cells relative to the battery case 10 in the battery module according to the first embodiment. Fig. 8 shows the displacement amounts of the first cell and the ninth cell when the cells are counted from the inlet side of the first chamber 11a. Also, Fig. 8 shows the displacement amount of the end of the first battery stack 1a on the rail 12a side as the Fr-side displacement amount, and the displacement amount of the first battery cell in the left-right direction as the displacement amount LH. Furthermore, Fig. 8 shows a graph after the end of the first battery stack 1a comes into contact with the first end wall 14a.

[0033] As shown in FIG. 8, when the end of the first battery stack 1a contacts the first end wall 14a, the pressing load generated by the pressing tool 41 increases as the pressing amount increases. As the pressing load increases, the left-right displacement amount LH of the first cell increases. As the pressing load increases, the Fr-side displacement amounts of the first and ninth cells also increase. At this time, the Fr-side displacement amount of the first cell is greater than the Fr-side displacement amount of the ninth cell. This difference in the Fr-side displacement amounts occurs because the effect of the rotation of the battery case 10 on the Fr-side displacement amount is stronger on the first cell, which is farther from the rotation axis.

[0034] As explained above, in the battery module according to the first embodiment, the inclination of the battery stack is large near the inlet of the chamber and small near the end wall, and the cross-sectional shape of the chamber is set to gradually decrease in the depth direction of the chamber, thereby generating a vortex airflow even near the end wall. As a result, in the battery module according to the first embodiment, the efficiency of sending the cooling air to the spacer 3 can be increased, and pressure loss can be reduced particularly near the end wall. And, in the dentin module according to the first embodiment, it becomes possible to increase the cooling efficiency of the battery cells arranged near the end wall of the chamber.

[0035] Embodiment 2 In the second embodiment, a battery case 50 will be described as another example of the battery case 10 according to the first embodiment. In the description of the second embodiment, the same components as those described in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

[0036] FIG. 9 is a schematic diagram of a battery case 50 according to the second embodiment. As shown in FIG. 9, the battery case 50 according to the second embodiment has a first end wall 54a and a second end wall 54b instead of the first end wall 14a and the second end wall 14b of the battery case 10 according to the first embodiment. The first end wall 54a and the second end wall 54b are provided with notches that reduce the thickness of the battery stack end region, and the notched portions are defined as low-rigidity portions Ww. On the other hand, the first end wall 54a and the second end wall 54b have a uniform thickness in the high-rigidity portions Ws.

[0037] Next, a manufacturing method of the battery module according to the second embodiment will be described. FIG. 10 shows a diagram for explaining the manufacturing method of the battery module according to the second embodiment. As shown in FIG. 10, in the battery module according to the second embodiment, the first battery stack 1a is pressed against the first end wall 54a, and a pressure is applied to the first battery stack 1a after the end of the first battery stack 1a comes into contact with the first end wall 54a. At this time, in the second embodiment, the battery case 10 rotates clockwise around the high rigidity portion Ws as in the first embodiment, and the first battery stack 1a is tilted with respect to the extension direction of the rail 12a. As a result, in the second embodiment, the amount of deviation of the leg 32 with respect to the rail 12a increases from the closing wall toward the inlet of the first chamber 11a as in the first embodiment. Moreover, due to this rotation of the battery case 10, the inclination of the battery stack with respect to the horizontal direction increases from the closing wall toward the inlet of the first chamber 11a.

[0038] As described above, by providing the high-rigidity portion Ws and the low-rigidity portion Ww in the left-right direction of the wall surface of the battery case against which the battery stack is pressed, it becomes possible to rotate the battery case in the manufacturing process. By rotating the battery case, the battery stack is tilted relative to the battery case, and the shape of the chamber can be such that the cross-sectional area substantially narrows as it progresses in the depth direction Y, and the shape is asymmetric in the left-right direction. By creating such a chamber shape, it becomes possible to reduce pressure loss near the end wall and increase the cooling efficiency of the battery cells, even in the second embodiment.

[0039] In the above embodiment, an example was described in which two chambers are provided for one air outlet to generate a vortex airflow in the area near the chamber entrance, but even if one chamber is provided for one air outlet, a vortex airflow can be generated near the chamber entrance by tilting the airflow direction into the chamber with respect to the extension direction of the duct. In other words, even if the configuration of the battery module described above is adopted for a battery module stored in a battery case in which one chamber is provided for one air outlet, a vortex airflow can be generated near the end of the chamber to reduce pressure loss.

[0040] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0041] 1, 1a, 1b Battery stack 2 Battery Cells 3 Spacer 10 Battery case 11a, 11b Chambers 12a, 12b rails 13a, 13b rails 14a, 14b End wall 15a, 15b Battery stack storage section 20 Wind guide 20a Diversion structure 21 Ventilation vent 31 Ribs 32 Legs 33 Legs 41 Pressurizing tool 42 Pressure plate 43 Receiving jig 50 Battery case 54a, 54b End wall Ww Low rigidity part Ws High rigidity part

Claims

1. a battery stack in which a plurality of battery cells and spacers each having a cooling air flow path through which cooling air flows are alternately stacked; a battery case including: a battery stack storage section that stores the battery stack; a chamber in which the cooling air inlet and an end wall that blocks the cooling air are provided opposite each other in a first direction, the chamber having an opening on a surface that contacts the inlet of the cooling air flow path; and a pair of rails that are provided on both ends of the opening along the first direction in which the chamber extends; The battery stack is a battery module in which, when the direction from one of the pair of rails to the other is defined as the horizontal direction, the battery stack is stored in the battery stack storage section so that the inclination with respect to the horizontal direction increases from the end wall toward the inlet.

2. The spacer has legs formed at positions spanning the outer sides of the pair of rails, 2. The battery module according to claim 1, wherein when the battery stack is stored in the battery stack storage section, the amount of vertical misalignment between the leg and one of the pair of rails increases from the end wall toward the inlet.

3. 2. The battery module according to claim 1, wherein the end wall has a battery stack end region against which an end of the battery stack is pressed in the battery stack storage section, and the battery stack end region has a low-rigidity portion formed on one side in the horizontal direction that has lower rigidity than the other side.

4. The battery module according to claim 3 , wherein the low rigidity portion is provided with a notch for reducing a thickness of the battery stack terminal region.

5. The battery module according to claim 3 , wherein the battery stack terminal region is formed so that a wall thickness thereof gradually decreases from one side to the other side in the horizontal direction.

6. the battery case includes two sets of the battery stack storage section, the chamber, and the pair of rails; the battery stack includes a first battery stack accommodated in one of the battery stack storage sections and a second battery stack accommodated in the other battery stack storage section, 2. The battery module according to claim 1, wherein a first inclination of the first battery stack and a second inclination of the second battery stack are set to be linearly symmetrical with respect to a vertical direction perpendicular to both the first direction and the horizontal direction.

7. The battery module according to claim 6 , wherein the first inclination and the second inclination are set in a direction that opens away from the axis of symmetry in the horizontal direction.

8. a battery stack in which a plurality of battery cells and spacers each having a cooling air flow path through which cooling air flows and a leg portion are alternately stacked; a battery case including: a battery stack storage section for storing the battery stack; a chamber in which the cooling air inlet and a closing wall for blocking the cooling air are provided opposite each other in a first direction, and an opening surface is provided on a surface that contacts the inlet of the cooling air flow path; a pair of rails provided along the first direction on both ends of the opening surface; and an end wall of the battery stack storage section in which a low-rigidity portion having a lower rigidity is provided on one side of the pair of rails in a horizontal direction from one side to the other side of the pair of rails, the low-rigidity portion being lower in rigidity than the other side of the pair of rails, a receiving jig is brought into contact with the end wall from the outside of the battery case; inserting the battery stack into the battery stack storage section in a direction parallel to the first direction until the battery stack reaches the end wall; a battery stack storage section that stores the battery stack in the battery stack storage section so that, after the battery stack reaches the end wall, a pressure is applied so that the battery stack presses the end wall, thereby rotating the battery case, thereby increasing the amount of deviation of the legs relative to the rails from the closing wall toward the inlet, and so that the inclination of the battery stack with respect to the horizontal direction increases from the closing wall toward the inlet.

9. the battery case includes two sets of the battery stack storage section, the chamber, and the pair of rails; the battery stack includes a first battery stack accommodated in one of the battery stack storage sections and a second battery stack accommodated in the other battery stack storage section, 9. The method for manufacturing a battery module according to claim 8, wherein a first inclination of the first battery stack and a second inclination of the second battery stack are set to be linearly symmetrical with respect to a vertical direction perpendicular to both the first direction and the horizontal direction.

10. The method for manufacturing a battery module according to claim 9 , wherein the first inclination and the second inclination are set in a direction that opens away from the axis of symmetry in the horizontal direction.

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