Battery case and battery pack containing the same, and automobile

Abstract

This invention provides a battery case with improved airtightness. [Solution] The battery case according to the present invention includes a pack frame configured to form a housing space for a plurality of battery cells, a case lead configured to cover the housing space, and a gasket interposed between the pack frame and the case lead, wherein the gasket includes a plurality of joints which are areas pressed by a fastening member, and at least one separation portion disposed between adjacent joints, and the thickness of the first location of the plurality of joints may differ from the thickness of the second location of the at least one separation portion.

Description

[Technical Field]

[0001] The present invention relates to a battery case, a battery pack including the same, and an automobile. [Background Art]

[0002] With the rapid increase in demand for portable electronic devices such as notebook computers, video cameras, and mobile phones, and the full-scale commercialization of robots, electric vehicles and the like, research on high-performance secondary batteries that can be repeatedly charged and discharged has been actively promoted.

[0003] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. Among these, compared with nickel-based secondary batteries, when charging a lithium secondary battery from a state where the battery is not completely discharged, the memory effect, which is a phenomenon in which the chargeable capacity of the battery decreases, hardly occurs. Therefore, lithium secondary batteries are in the spotlight for their advantages of allowing free charging and discharging, having an extremely low self-discharge rate, and furthermore having a high energy density.

[0004] In such a lithium secondary battery, lithium-based oxides and carbon materials are mainly used as a positive electrode active material and a negative electrode active material, respectively. A lithium secondary battery comprises: an electrode assembly in which a positive electrode plate coated with the positive electrode active material and a negative electrode plate coated with the negative electrode active material are disposed with a separation membrane interposed therebetween; and an exterior member that houses the electrode assembly together with an electrolytic solution in a sealed state, that is, a battery case.

[0005] Generally, lithium secondary batteries can be classified according to the shape of the exterior member into can-type secondary batteries in which the electrode assembly is incorporated in a metal can, and pouch-type secondary batteries in which the electrode assembly is incorporated in a pouch made of an aluminum laminate sheet.

[0006] In recent years, secondary batteries have been widely used not only in small devices such as portable electronic devices, but also in medium- and large-scale devices such as electric vehicles and energy storage systems (ESS), for propulsion and energy storage.

[0007] Such a secondary battery can be configured as a single battery module, with numerous battery cells electrically connected and housed together inside a module case. A battery pack can then be constructed by electrically reconnecting these battery modules in a confined space to increase energy density.

[0008] The battery case included in such a battery module or battery pack is equipped with a gasket to seal the internal space. However, depending on the location of the gasket, there are areas where the airtightness is reduced, leading to a problem of gases generated inside leaking from these areas. Therefore, there is a need to develop a battery case that improves airtightness and maintains a certain level of airtightness or higher throughout its entire surface. [Overview of the project] [Problems that the invention aims to solve]

[0009] This invention was conceived in view of the above-mentioned problems, and one of its objectives is to provide a battery case with improved airtightness. [Means for solving the problem]

[0010] A battery case according to one embodiment of the present invention includes a pack frame configured to form a housing space for a plurality of battery cells, a case lead configured to cover the housing space, and a gasket interposed between the pack frame and the case lead, wherein the gasket includes a plurality of joints which are areas pressurized by a fastening member, and at least one separation portion disposed between adjacent joints, and the thickness of the first location of the plurality of joints may differ from the thickness of the second location of the at least one separation portion.

[0011] The gasket may be thicker at the second location than at the first location.

[0012] The gasket may be thinner at the second location than 1.167 times the thickness of the first location.

[0013] The gasket may have a thickness at the second location equal to or greater than 1.033 times the thickness at the first location, and a thickness at or less than 1.1 times the thickness at the first location.

[0014] The gasket may have a thickness at the second location that is 1.067 times the thickness at the first location.

[0015] The gasket may be thickest at the second location.

[0016] The second location can be defined as the midpoint of the adjacent joint.

[0017] The thickness gradient of the section between adjacent joints may be symmetrical around the second location.

[0018] The gasket may have a second location within the maximum thickness section of the separation area.

[0019] The gasket is located in the center between adjacent joints and may include a maximum thickness section that is the same thickness as the second location.

[0020] The length of the maximum thickness section may be greater than 0.1 times the length between adjacent joints and less than 0.15 times the length between adjacent joints.

[0021] The gasket may include a sloping section having a thickness that is thinner than the thickness at the second location but thicker than the thickness at the first location.

[0022] The inclined sections may include a first inclined section adjacent to one of adjacent joint portions and starting from a position where the maximum thickness section ends, and a second inclined section adjacent to the other of the adjacent joint portions and starting from a position where the maximum thickness section ends.

[0023] The length of the first inclined section and the length of the second inclined section may be the same as the length of the maximum thickness section.

[0024] A battery pack according to an embodiment of the present invention may include the battery case according to the present invention.

[0025] An automobile according to an embodiment of the present invention may include the battery pack according to the present invention.

Effects of the Invention

[0026] According to an embodiment of the present invention, airtightness can be made substantially constant over the entire region of the gasket. Since the gasket is directly pressed by the fastening member only at the plurality of joint portions, the pressing force at the spaced portion can be relatively lower than that at the joint portions. Here, by making the thickness of the spaced portion larger than the thickness of the joint portions, the plurality of joint portions of the gasket are directly pressed through the fastening member to ensure airtightness, and the spaced portion can ensure airtightness through the increased thickness. Therefore, when the internal pressure of the battery case increases, this prevents gas from leaking between the case lead and the gasket in the region corresponding to the spaced portion, or between the pack frame and the gasket, due to a pressure lower than the designed venting pressure, and allows the gas to be discharged to a desired location through a venting device or the like.

Brief Description of Drawings

[0027] [Figure 1] It is an exploded perspective view of a battery case according to an embodiment of the present invention. [Figure 2] It is an assembled perspective view of a battery case according to an embodiment of the present invention. [Figure 3] It is a diagram showing a gasket included in a battery case according to an embodiment of the present invention. [Figure 4] This figure shows the relationship between the pack frame, case lead, gasket, and fastening member included in a battery case according to one embodiment of the present invention. [Figure 5] This figure shows the thickness gradient of a gasket included in a battery case according to one embodiment of the present invention. [Figure 6] This figure shows the simulation results from Comparative Example 1. [Figure 7] This figure shows the simulation results according to Example 1 of the present invention. [Figure 8] This figure shows the simulation results according to Example 2 of the present invention. [Figure 9] This figure shows the simulation results according to Example 3 of the present invention. [Figure 10] This figure shows the simulation results according to Example 4 of the present invention. [Figure 11] This figure shows the simulation results according to Example 5 of the present invention. [Figure 12] This figure shows the simulation results from Comparative Example 2. [Figure 13] This is a diagram showing an automobile relating to one embodiment of the present invention. [Modes for carrying out the invention]

[0028] Prior to a detailed description of the present invention, terms and other symbols used herein and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, based on the principle that inventors may appropriately define terms and other symbols in order to best describe their invention. Accordingly, the embodiments described herein and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and it should be understood that, at the time of filing this application, there may be a variety of equivalents and modifications that can substitute for them.

[0029] The same reference numerals in the drawings accompanying this specification indicate parts or components that perform substantially the same function. For convenience of explanation and understanding, different embodiments may also be described using the same reference numerals. That is, even if multiple figures show components with the same reference numerals, not all of the figures represent a single embodiment.

[0030] In the following descriptions, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as “contains” or “constitutes” are intended to specify the presence of features, figures, stages, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preemptively exclude the presence or possibility of adding one or more other features, figures, stages, operations, components, parts, or combinations thereof.

[0031] It should be noted that in the following explanation, terms such as "top," "upper," "lower," "bottom," "side," "front," and "rear" are used based on the direction shown in the drawing, and may be expressed differently if the direction of the object changes.

[0032] Furthermore, in this specification and claims, terms including ordinal numbers, such as "first," "second," etc., may be used to distinguish between components. Such ordinal numbers are used to distinguish identical or similar components from one another, and the use of such ordinal numbers should not restrict the meaning of the terms. For example, the order of use or arrangement of components combined with such ordinal numbers should not be restricted by the numbers. If necessary, the ordinal numbers may be used interchangeably with each other.

[0033] Embodiments of the present invention will be described below with reference to the attached drawings. However, the concept of the present invention is not limited to the embodiments presented. For example, a person skilled in the art who understands the concept of the present invention may propose other embodiments that fall within the scope of the present invention through the addition, modification, or deletion of components, and these too can be said to fall within the scope of the present invention. The shapes and sizes of elements in the drawings may be exaggerated for clearer explanation.

[0034] Figure 1 is an exploded perspective view of a battery case 100 according to one embodiment of the present invention. Figure 2 is a coupled perspective view of a battery case 100 according to one embodiment of the present invention.

[0035] Referring to Figures 1 and 2, the battery case 100 may include a pack frame 120, case leads 130, and a gasket 140.

[0036] The pack frame 120 may be configured to form a housing space for multiple battery cells 10. A battery module containing multiple battery cells 10 can be housed in the housing space. For example, when the pack frame 120 houses multiple battery modules, the pack frame 120 may comprise a frame body 123 and partition walls 125. The frame body 123 is configured in a box shape with an open top and can house multiple battery cells 10 inside. The partition walls 125 can partition the internal space of the frame body 123. The partition walls 125 may be provided in spaces corresponding to the spaces between multiple adjacent battery cells 10. On the other hand, the pack frame 120 is not limited to the structure illustrated and described herein; for example, the frame body 123 may be composed of a bottom plate, end plates, front plates, and side plates.

[0037] The case lead 130 may be configured to cover the storage space. The case lead 130 may be configured in the form of a lid that covers the upper opening of the pack frame 120 body.

[0038] The gasket 140 may be interposed between the pack frame 120 and the case lead 130. The gasket 140 may seal the space between the pack frame 120 and the case lead 130. The gasket 140 may be interposed along the periphery of the pack frame 120 and the case lead 130.

[0039] Figure 3 shows a gasket 140 included in a battery case 100 according to one embodiment of the present invention. Figure 4 shows the coupling relationship between the pack frame 120, case lead 130, gasket 140, and fastening member 110 included in a battery case 100 according to one embodiment of the present invention. Figure 5 shows the thickness gradient of the gasket 140 included in a battery case 100 according to one embodiment of the present invention.

[0040] Referring to Figures 3 to 5, the gasket 140 may include a plurality of connecting portions 143 and separating portions 145.

[0041] Multiple connecting parts 143 can be pressurized by fastening members 110. The fastening members 110 may be screws.

[0042] Multiple connecting portions 143 can be separated by a predetermined distance from adjacent connecting portions 143. The connecting portions 143 may be areas that are directly pressurized by the fastening member 110 when the fastening member 110 is connected to the case lead 130.

[0043] The separation portion 145 may be positioned between adjacent connecting portions 143. The separation portion 145 may be a region that is indirectly pressurized by the fastening member 110 when the fastening member 110 is connected to the case lead 130.

[0044] For example, if the fastening member 110 is a screw, the connecting portion 143 may be the region orthogonally projected onto the lower surface of the screw head, and the separating portion 145 may be the remaining region excluding the connecting portion 143.

[0045] The thickness of the first location A of the joint 143 may differ from the thickness of the second location B of the separation portion 145. That is, at least a portion of the separation portion 145 may have a different thickness from the joint 143. The thickness of the joint 143 may be constant throughout its entire area. This is to facilitate fastening when the fastening member 110 is joined to the joint 143.

[0046] The thickness of the second location B may be greater than the thickness of the first location A. That is, the thickness of at least a portion of the separation portion 145 may be greater than the thickness of the joint portion 143.

[0047] According to this configuration of the present invention, airtightness can be maintained substantially constant throughout the entire area of ​​the gasket 140. Since the gasket 140 is directly pressurized by the fastening member 110 only at the multiple joints 143, the pressure applied to the separation portion 145 may be relatively lower compared to the joints 143. By making the thickness of the separation portion 145 thicker than the thickness of the joints 143, airtightness can be ensured at the multiple joints 143 of the gasket 140 by direct pressurization through the fastening member 110, and at the separation portion 145 by the increased thickness. Therefore, when the internal pressure of the battery case 100 increases, gas leakage from between the case lead 130 and the gasket 140, or between the pack frame 120 and the gasket 140, in the area corresponding to the separation portion 145 can be prevented at a pressure lower than the designed venting pressure. Furthermore, even if the internal pressure increases further and becomes higher than the venting pressure, the gas can be discharged to the desired location through a venting device or the like.

[0048] As mentioned above, the thickness of the separation portion 145 can be configured so that it is pressurized to the same or similar degree in the region of the joint portion 143. In other words, if the thickness of the separation portion 145 is configured to be excessively thick, the airtightness may actually decrease, so an appropriate thickness setting is required.

[0049] Therefore, simulations were performed to determine the appropriate thickness of the separation portion 145. The simulations were performed assuming a case lead 130 thickness of 2 mm, a joint portion 143 thickness of the gasket 140 of 3 mm, and fastening member 110 with a torque of 10 Nm. In this case, the minimum contact pressure of the gasket 140 was measured in the region between adjacent joint portions 143 while adjusting the thickness of the separation portion 145. The measurement results are as follows.

[0050] [Table 1]

[0051] Figure 6 shows the simulation results according to Comparative Example 1. Figure 7 shows the simulation results according to Example 1 of the present invention. Figure 8 shows the simulation results according to Example 2 of the present invention. Figure 9 shows the simulation results according to Example 3 of the present invention. Figure 10 shows the simulation results according to Example 4 of the present invention. Figure 11 shows the simulation results according to Example 5 of the present invention. Figure 12 shows the simulation results according to Comparative Example 2.

[0052] Comparative examples and simulation results according to the embodiments of the present invention will be explained with reference to Figures 6 to 12.

[0053] In Comparative Example 1, where the thickness of the second location B of the separation portion 145 and the thickness of the first location A of the joint portion 143 were both set to 3 mm, the minimum contact pressure of the gasket 140 was measured to be 5 MPa.

[0054] In Example 1, where the thickness of the second location B of the separation portion 145 was set to 1.033 times the thickness of the first location A of the joint portion 143, the contact pressure of the gasket 140 increased by 12% compared to Comparative Example 1.

[0055] In Example 2, where the thickness of the second location B of the separation portion 145 was set to 1.067 times the thickness of the first location A of the joint portion 143, the contact pressure of the gasket 140 increased by 22% compared to Comparative Example 1.

[0056] In Example 3, where the thickness of the second location B of the separation portion 145 was set to 1.1 times the thickness of the first location A of the joint portion 143, the contact pressure of the gasket 140 increased by 18% compared to Comparative Example 1.

[0057] In Example 4, where the thickness of the second location B of the separation portion 145 was set to 1.133 times the thickness of the first location A of the joint portion 143, the contact pressure of the gasket 140 increased by 12% compared to Comparative Example 1.

[0058] In Example 5, where the thickness of the second location B of the separation portion 145 was set to 1.167 times the thickness of the first location A of the joint portion 143, the contact pressure of the gasket 140 increased by 4% compared to Comparative Example 1.

[0059] Comparative Example 2, in which the thickness of the second location B of the separation portion 145 was set to 1.2 times the thickness of the first location A of the joint portion 143, showed a 4% reduction in the contact pressure of the gasket 140 compared to Comparative Example 1.

[0060] Looking at the overall simulation data, when the thickness of the second location B of the separation portion 145 was set to 1.067 times the thickness of the first location A of the joint portion 143, the contact pressure of the gasket 140 increased the most compared to Comparative Example 1. Furthermore, according to Comparative Example 2, when the thickness of the second location B of the separation portion 145 was set to 1.2 times the thickness of the first location A of the joint portion 143, the contact pressure actually decreased compared to Comparative Example 1.

[0061] Therefore, in order to increase the contact pressure of the gasket 140 compared to Comparative Example 1, the thickness of the separation portion 145 can satisfy the following numerical range.

[0062] The thickness of the second location B may be greater than the thickness of the first location A, and may be equal to or less than 1.167 times the thickness of the first location A.

[0063] The thickness of the second location B may be greater than the thickness of the first location A, and may be equal to or less than 1.133 times the thickness of the first location A.

[0064] The thickness of the second location B may be thicker than the thickness of the first location A, or it may be equal to or thinner than 1.1 times the thickness of the first location A.

[0065] The thickness of the second location B may be greater than the thickness of the first location A, and may be equal to or less than 1.067 times the thickness of the first location A.

[0066] The thickness of the second location B may be equal to or greater than 1.033 times the thickness of the first location A, or equal to or less than 1.167 times the thickness of the first location A.

[0067] The thickness of the second location B may be equal to or greater than 1.033 times the thickness of the first location A, or equal to or less than 1.133 times the thickness of the first location A.

[0068] The thickness of the second location B may be equal to or greater than 1.033 times the thickness of the first location A, or it may be equal to or less than 1.1 times the thickness of the first location A.

[0069] The thickness of the second location B may be equal to or greater than 1.033 times the thickness of the first location A, or equal to or less than 1.067 times the thickness of the first location A.

[0070] The thickness of the second location B may be equal to or greater than 1.067 times the thickness of the first location A, or equal to or less than 1.167 times the thickness of the first location A.

[0071] The thickness of the second location B may be equal to or greater than 1.067 times the thickness of the first location A, or equal to or less than 1.133 times the thickness of the first location A.

[0072] The thickness of the second location B may be equal to or greater than 1.067 times the thickness of the first location A, or it may be equal to or less than 1.1 times the thickness of the first location A.

[0073] The thickness of the second location B may be equal to or greater than 1.1 times the thickness of the first location A, or it may be less than 1.167 times the thickness of the first location A.

[0074] The thickness of the second location B may be equal to or greater than 1.1 times the thickness of the first location A, or equal to or less than 1.133 times the thickness of the first location A.

[0075] The thickness of the second location B may be equal to or greater than 1.133 times the thickness of the first location A, or equal to or less than 1.167 times the thickness of the first location A.

[0076] Preferably, the thickness of the second location B may be equal to or greater than 1.033 times the thickness of the first location A, or equal to or less than 1.133 times the thickness of the first location A.

[0077] Preferably, the thickness of the second location B may be equal to or greater than 1.033 times the thickness of the first location A, or equal to or less than 1.1 times the thickness of the first location A.

[0078] Preferably, the thickness of the second location B may be equal to or greater than 1.067 times the thickness of the first location A, or equal to or less than 1.1 times the thickness of the first location A.

[0079] Preferably, the thickness of the second location B may be 1.067 times the thickness of the first location A.

[0080] Refer again to Figure 5 for a more detailed explanation of gasket 140 used in the simulation.

[0081] The gasket 140 may have its thickest point at the second location B. The second location B can be defined as the central point M between two adjacent joints 143A and 143B.

[0082] The thickness gradient of the gasket 140 between two adjacent joints 143A and 143B may be symmetrical around the second location B.

[0083] The gasket 140 may include a maximum thickness section L1. The second location B may be located within the maximum thickness section L1. The maximum thickness section L1 may be located in the center between two adjacent joints 143A and 143B.

[0084] In the gasket 140, regions with different thicknesses (L1, L2, and L3 in Figure 5) may have a certain margin region from the boundary of the adjacent joint 143. The margin region may refer to a region within the separation portion 145 whose thickness is the same as that of the joint 143. If regions L1, L2, and L3 with different thicknesses are located in the center of the separation portion 145, margin regions may be provided on both sides between the adjacent joint 143. Within the separation portion 145, the region adjacent to the joint 143 is subjected to indirect forces due to the pressurization of the fastening member 110, depending on the material properties of the gasket 140, and airtightness is ensured in a considerable area. Therefore, the separation portion 145 may have different thicknesses, mainly in the central region where airtightness is relatively reduced.

[0085] For example, the length of the maximum thickness section L1 may be greater than 0.1 times the length L between two adjacent joints 143A and 143B, and less than 0.15 times the length L between two adjacent joints 143A and 143B. In the simulation model, the length L between the two joints 143A and 143B was set to 70 mm, and the length of the maximum thickness section L1 was set to 8 mm.

[0086] The gasket 140 may include an inclined section. The inclined section may be thinner than the thickness of the second location B, but thicker than the thickness of the first location A. That is, the inclined section may be thinner than the thickness of the maximum thickness section L1, but thicker than the thickness of the joint 143.

[0087] The inclined section may include a first inclined section L2 and a second inclined section L3. The first inclined section L2 may begin adjacent to one of the two adjacent joints 143A and 143B, at the point where the maximum thickness section L1 ends. The second inclined section L3 may begin adjacent to the other of the two adjacent joints 143A and 143B, at the point where the maximum thickness section L1 ends.

[0088] The length of the first inclined section L2 may be the same as the length of the maximum thickness section L1. The length of the second inclined section L3 may be the same as the length of the maximum thickness section L1. In the simulation model, the lengths of the first inclined section L2 and the second inclined section L3 were set to 8 mm, which is the same as the length of the maximum thickness section L1.

[0089] In yet another embodiment, by including an inclined section that forms a gentle slope from the second location B of the separation portion 145 to the boundary of the joint portion 143, that is, by configuring it so that there is no margin area, the airtightness of the gasket 140 can be ensured.

[0090] In yet another embodiment, the regions of varying thickness may have a curved shape overall, rather than a straight slope, with the thickness gradually increasing or decreasing to minimize the occurrence of discontinuous protrusions.

[0091] Referring again to Figure 1, the battery pack 3 may include a battery case 100. The battery pack 3 may further include, although not shown in the drawings, a number of battery cells 10 and various other components besides the battery case 100, such as components of the battery pack 3 that were known at the time of filing of the present invention, such as a BMS, relays, current sensors, etc.

[0092] Figure 13 shows an automobile 1 according to the present invention.

[0093] Referring to Figure 13, the automobile 1 may include the battery pack 3. In addition to the battery pack 3, the automobile 1 may further include various other components included in the automobile 1. For example, in addition to the battery pack 3 according to the present invention, the automobile 1 may further include the vehicle body, motor, control device such as an ECU (electronic control unit), etc.

[0094] As described above, the present invention has been described primarily in terms of preferred embodiments with reference to the accompanying drawings, but it will be clear to those skilled in the art that many diverse and obvious modifications are possible without departing from the scope of the invention. Therefore, the scope of the invention should be interpreted as being in line with the claims, which are described to include such many modifications. [Explanation of Symbols]

[0095] 1: Automobile 3: Battery pack 10: Battery cell 100: Battery case 110: Fastening member 120: Pack Frame 123: Frame body 125: Bulkhead 130: Case Lead 140: Gasket 143:Joining part 143A: One of the joints 143B: The other joint A: First location 145: Separation part B: Second location M: Center L: Length between adjacent joints L1: Maximum thickness section L2: First incline section L3: Second incline section

Claims

1. It is a battery case, A pack frame configured to form a space for housing multiple battery cells, A case lead configured to cover the aforementioned storage space, The pack frame and the case lead are interposed gaskets, The aforementioned gasket is Multiple joints which are regions that are pressurized by the fastening member, It includes at least one separating portion positioned between adjacent joints, A battery case in which the thickness of the first location of the plurality of joints is different from the thickness of the second location of the at least one separation portion.

2. The aforementioned gasket is The battery case according to claim 1, wherein the thickness of the second location is greater than the thickness of the first location.

3. The aforementioned gasket is The battery case according to claim 2, wherein the thickness of the second location is less than 1.167 times the thickness of the first location.

4. The aforementioned gasket is The battery case according to claim 3, wherein the thickness of the second location is equal to or greater than 1.033 times the thickness of the first location, and equal to or less than 1.1 times the thickness of the first location.

5. The aforementioned gasket is The battery case according to claim 3, wherein the thickness of the second location is 1.067 times the thickness of the first location.

6. The aforementioned gasket is The battery case according to claim 2, wherein the thickness is greatest at the second location.

7. The second part mentioned above is, The battery case according to claim 6, defined as the central portion of the adjacent joint portions.

8. The aforementioned gasket is The battery case according to claim 7, wherein the thickness gradient of the section between adjacent joint portions is symmetrical with respect to the center of the second location.

9. The aforementioned gasket is The battery case according to claim 8, wherein the second location is included within the maximum thickness section of the separation portion.

10. The length of the aforementioned maximum thickness section is, The battery case according to claim 9, wherein the length is greater than 0.1 times the length between adjacent joints and less than 0.15 times the length between adjacent joints.

11. The aforementioned gasket is The battery pack case according to claim 9, further comprising a sloping section having a thickness thinner than the thickness of the second location and thicker than the thickness of the first location.

12. The aforementioned sloping section is, The battery pack case according to claim 11, comprising: a first inclined section adjacent to one of the adjacent joints, beginning at the end of the maximum thickness section; and a second inclined section adjacent to the other of the adjacent joints, beginning at the end of the maximum thickness section.

13. The length of the first inclined section and the length of the second inclined section are: The battery pack case according to claim 12, wherein the length is the same as the maximum thickness section.

14. A battery pack comprising a battery pack case according to any one of claims 1 to 13.

15. An automobile comprising the battery pack described in claim 14.

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