A battery pack having a structure capable of swelling control and an automobile including the same

Abstract

A battery pack according to an embodiment of the present invention includes a plurality of battery modules, a pack tray for accommodating the plurality of battery modules, a module cover for covering an opening formed in an upper portion of the pack tray, a pack cover for covering the module cover, and an upper elastic member interposed between the module cover and the pack cover, and compressed as the module cover moves toward the pack cover due to swelling of the battery module, thereby absorbing volumetric expansion due to the swelling.

Description

Technical Field

[0001] The present invention relates to a battery pack having a structure capable of controlling swelling and an automobile including the same. More specifically, the present invention relates to a structure capable of minimizing the amount of swelling generated along the stacking direction of a cell stack by minimizing the stacking thickness of one cell stack, and further to a battery pack having a structure in which the pressure applied to the battery cells increases relatively constantly as the amount of swelling increases, and an automobile including the same.

[0002] This application claims priority based on Korean Patent Application No. 10-2020-0152314 filed on November 13, 2020, and all of the contents disclosed in the specification and drawings of the application are incorporated into this application.

Background Art

[0003] Generally, in the case of a conventional battery pack, in order to control the swelling of battery cells, a structure in which buffer pads are inserted between adjacent battery cells and / or at the outermost periphery of the cell stack, a structure in which a space is secured in the pack housing in consideration of the volume expansion due to the swelling of the battery cells, or a structure in which the pack housing is deformed by the swelling of the battery cells to absorb the swelling is provided.

[0004] In such a structure of a conventional battery pack, as the number of battery cells constituting the cell stack increases, a larger empty space needs to be secured and / or a larger number of buffer pads need to be applied according to the increasing amount of swelling. Also, usually in such a conventional structure, the battery cells are stacked along a direction parallel to the ground or the bottom surface of the pack housing. Such a structure is disadvantageous in terms of ensuring the structural rigidity of the battery pack and ensuring a high energy density.

[0005] Also, when using a buffer pad to absorb swelling, as the amount of swelling increases, the force required to compress the buffer pad further increases, thereby causing a problem that the pressure applied to the battery cell explosively increases.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made in view of the above problems, and eliminates the decrease in energy density due to the empty space for absorbing the volume expansion of the battery cell caused by swelling, ensures the structural rigidity of the battery pack, and also prevents the pressure applied to the battery cell from explosively increasing due to an increase in the amount of swelling. This is one object.

[0007] The technical problems to be solved by the present invention are not limited to the above problems, and other problems will be clearly understood by those skilled in the art from the following description of the invention.

Means for Solving the Problems

[0008] To solve the above-described problems, a battery pack according to an aspect of the present invention includes a plurality of battery modules, a pack tray that houses the plurality of battery modules, a module cover that covers an opening formed in an upper portion of the pack tray, a pack cover that covers the module cover, and an upper elastic member that is interposed between the module cover and the pack cover and absorbs the volume expansion due to swelling while being compressed as the module cover moves toward the pack cover due to swelling of the battery module.

[0009] The battery module may include a module tray including a tray base and a tray partition that extends in a direction perpendicular to the tray base and divides a placement space on the tray base along the width direction of the tray base, a first cell stack disposed on the module tray and disposed on one side of the tray partition, and a second cell stack disposed on the module tray and disposed on the other side of the tray partition.

[0010] The upper elastic member may include a first upper elastic member disposed at a position corresponding to the first cell stack and a second upper elastic member disposed at a position corresponding to the second cell stack.

[0011] Each of the first cell stack and the second cell stack may include a plurality of battery cells stacked along a direction perpendicular to the tray base.

[0012] The pack tray may include a dividing beam that divides an accommodation space of the battery module formed inside the pack tray along the width direction of the pack tray, and a cross beam that divides the space divided by the dividing beam along the longitudinal direction of the pack tray.

[0013] The module cover and the pack cover are fastened to the pack tray by bolts passing through the module cover and the pack cover, and the movement of the module cover due to the swelling may be guided by the bolts.

[0014] The bolts may include a first bolt that sequentially passes through the pack cover and the module cover and is fastened to the cross beam, and a second bolt that sequentially passes through the pack cover and the module cover and is fastened to the tray partition.

[0015] The pack cover includes a plurality of cover protrusions protruding from an inner surface of the pack cover, and the first upper elastic member and the second upper elastic member may be disposed between a pair of adjacent cover protrusions.

[0016] The pack cover includes a cover accommodation groove formed on an upper surface of the pack cover so that the first bolt and the second bolt are not exposed on the upper part of the pack cover, and the cover accommodation groove may be formed at a position corresponding to the cover protrusion.

[0017] The battery pack may be interposed between the pack tray and the tray base, and may further include a lower elastic member that absorbs volume expansion due to swelling while being compressed as the tray base moves toward the pack tray due to swelling of the battery module.

[0018] The lower elastic member may include a first lower elastic member disposed at a position corresponding to the first cell stack, and a second lower elastic member disposed at a position corresponding to the second cell stack.

[0019] The tray base is fastened to the tray partition by a third bolt passing through the pack tray and the tray base, and the movement of the tray base due to swelling may be guided by the third bolt.

[0020] The pack tray includes a tray protrusion protruding from an inner surface of the pack tray, and the first lower elastic member and the second lower elastic member may be respectively disposed between the tray protrusions adjacent to each other and the cross beam.

[0021] The pack tray includes a tray accommodation groove formed on a lower surface of the pack tray so that the third bolt is not exposed on the lower part of the pack tray, and the tray accommodation groove may be formed at a position corresponding to the tray protrusion.

[0022] On the other hand, in order to solve the above-described problems, an automobile according to another aspect of the present invention includes a battery pack according to an aspect of the present invention as described above.

Effects of the Invention

[0023] According to one aspect of the present invention, it is possible to eliminate a decrease in energy density due to an empty space for absorbing volume expansion of a battery cell due to swelling, ensure the structural rigidity of a battery pack, and prevent the pressure applied to the battery cell from explosively increasing due to an increase in the amount of swelling.

[0024] The following drawings attached to this specification illustrate desirable embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention. Therefore, the present invention should not be construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in this specification and the claims should not be construed as being limited to ordinary or dictionary meanings. The inventor himself must interpret them in accordance with the meaning and concept corresponding to the technical idea of the present invention in accordance with the principle that he can appropriately define the concept of the terms in order to explain the invention in the best way. Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, there may be various equivalents and modifications that can replace them at the time of this application.

[0027] Referring to FIGS. 1 to 5, the battery pack 1 includes a plurality of battery modules 10, a pack tray 20, a module cover 30, a pack cover 40, and an upper elastic member 50.

[0028] Each of the plurality of battery modules 10 includes a module tray 100 and a cell stack 200. The battery module 10 may further include a pair of bus bar frame assemblies 300.

[0029] The module tray 100 includes a tray base 110 and a tray partition 120. The tray base 110 supports the cell stack 200 and is disposed on the inner bottom surface of the pack tray 20. The tray partition 120 extends in a vertical direction from the tray base 110 and divides the placement space on the tray base 110 along the width direction (X-axis direction) of the tray base 110.

[0030] The cell stack 200 is disposed on the tray base 110. The cell stack 200 includes a first cell stack 200A and a second cell stack 200B. The first cell stack 200A is disposed on the tray base 110 and on one side of the tray partition 120. The second cell stack 200B is disposed on the tray base 110 and on the other side of the tray partition 120.

[0031] The first cell stack 200A and the second cell stack 200B each include a plurality of battery cells 210 stacked along the vertical direction on the tray base 110. The battery cell 210 can be a pouch-type battery cell.

[0032] The pair of bus bar frame assemblies 300 are respectively coupled to the first cell stack 200A and the second cell stack 200B from one side and the other side in the longitudinal direction (Y-axis direction) of the module tray 100. That is, the pair of bus bar frame assemblies 300 are respectively coupled to one side and the other side in the longitudinal direction (Y-axis direction) of the first cell stack 200A and the second cell stack 200B. The pair of bus bar frame assemblies 300 can electrically connect the plurality of battery cells 210 to each other.

[0033] The pair of bus bar frame assemblies 300 each include a bus bar frame 310 and a bus bar 320. The bus bar frame 310 is provided with a lead slit 310a from which the electrode lead 211 of the battery cell 210 is drawn. The bus bar 320 is fixed on the bus bar frame 310 and can be coupled to the respective electrode leads 211 of the plurality of battery cells 210 by welding or the like.

[0034] The pack tray 20 houses a plurality of battery modules 10 in an accommodation space formed therein. The pack tray 20 includes a base plate forming the bottom and side plates forming the side walls. The pack tray 20 is provided with dividing beams 21 and a plurality of cross beams 22 to divide the internal accommodation space and enhance the structural rigidity of the battery pack 1.

[0035] The partition beam 21 divides the accommodation space of the battery module 10 formed inside the pack tray 20 along the width direction (Y-axis direction) of the pack tray 20. The cross beam 22 divides the space divided by the partition beam 21 along the longitudinal direction (X-axis direction) of the pack tray 20. The cross beam 22 is interposed between adjacent battery modules 10, and is also interposed between a pair of battery modules 10 located on the outermost periphery among the plurality of battery modules 10 arranged in the longitudinal direction (X-axis direction) of the battery pack 1 and the inner surface of the pack tray 20. Therefore, cross beams 22 are respectively located on one side and the other side in the width direction (X-axis direction) of all the battery modules 10.

[0036] The module cover 30 covers the opening formed in the upper part of the pack tray 20 and faces the battery module 10. The pack cover 40 is disposed above the module cover 30 and covers the module cover 30. The upper elastic member 50 is interposed between the module cover 30 and the pack cover 40. The upper elastic member 50 absorbs the volume expansion due to swelling while being compressed as the module cover 30 moves toward the pack cover 40 due to the swelling of the battery module 10. The module cover 30 may include a first module cover 30A that covers the battery module 10 located on one side of the partition beam 21 and a second module cover 30B that covers the battery module 10 located on the other side among the accommodation spaces of the battery modules 10 divided by the partition beam 21. When a plurality of module covers (30A, 30B) are provided in this way, since the swelling of each of the battery modules 10 accommodated in different spaces can be individually controlled, pressure can be uniformly applied to the plurality of battery modules 10.

[0037] The upper elastic member 50 may include a first upper elastic member 50A disposed at a position corresponding to the first cell laminate 200A and a second upper elastic member 50B disposed at a position corresponding to the second cell laminate 200B. Thus, the battery pack 1 according to an embodiment of the present invention has a structure in which swelling can be individually controlled for each battery module 10, and the swelling of the first cell laminate 200A and the second cell laminate 200B can be individually controlled.

[0038] The module cover 30 and the pack cover 40 are fastened to the pack tray 20 by bolts passing through the module cover 30 and the pack cover 40. The movement of the module cover 30 due to the swelling can be guided by the bolt B. The bolts include a first bolt B1 that sequentially passes through the pack cover 40 and the module cover 30 from above and is fastened to the cross beam 22, and a second bolt B2 that sequentially passes through the pack cover 40 and the module cover 30 from above and is fastened to the tray partition wall 120.

[0039] The pack cover 40 may include a plurality of cover protrusions 40a protruding from the inner surface of the pack cover 40. In this case, the first upper elastic member 50A and the second upper elastic member 50B are disposed between a pair of adjacent cover protrusions 40a, and the cover protrusions 40a can function as stoppers to prevent the first upper elastic member 50A and the second upper elastic member 50B from detaching from a predetermined position. The cover protrusions 40a may have a form extending long along the width direction (Y-axis direction) of the pack cover 40. The first bolt B1 and the second bolt B2 pass through the cover protrusions 40a.

[0040] The pack cover 40 may include a cover receiving groove 40b formed on the upper surface of the pack cover 40 so that the first bolt B1 and the second bolt B2 are not exposed above the pack cover 40. The cover receiving groove 40b is formed at a position corresponding to the cover protrusion 40a. The first bolt B1 and the second bolt B2 pass through the cover receiving groove 40b.

[0041] Referring to FIGS. 1 to 4 and FIG. 6, the battery pack 1 may further include a lower elastic member 60. The lower elastic member 60 is interposed between the pack tray 20 and the tray base 110. As the tray base 110 moves toward the base plate of the pack tray 20 due to the swelling of the battery module 10, the lower elastic member 60 absorbs the volume expansion due to swelling while being compressed.

[0042] The lower elastic member 60 may include a first lower elastic member 60A disposed at a position corresponding to the first cell laminate 200A and a second lower elastic member 60B disposed at a position corresponding to the second cell laminate 200B.

[0043] The tray base 110 is fastened to the tray partition wall by a third bolt B3 passing through the pack tray 20 and the tray base 110. The movement of the tray base 110 due to swelling may be guided by the third bolt B3.

[0044] The pack tray 20 may include a tray protrusion 20a protruding from the inner surface of the base plate of the pack tray 20. In this case, the first lower elastic member 60A and the second lower elastic member 60B are respectively disposed between the adjacent tray protrusions 20a and the cross beam 22. The tray protrusion 20a and the cross beam 22 can function as stoppers to prevent the first lower elastic member 60A and the second lower elastic member 60B from detaching from a predetermined position. The third bolt B3 passes through the tray protrusion 20a.

[0045] The pack tray 20 may include a tray receiving groove 20b formed on the lower surface of the base plate of the pack tray 20 so that the third bolt B3 is not exposed below the base plate of the pack tray 20. The tray receiving groove 20b is formed at a position corresponding to the tray protrusion 20a. The third bolt B3 passes through the tray receiving groove 20b.

[0046] On the one hand, as the upper elastic member 50 and the lower elastic member 60, for example, a leaf spring or a coil spring can be applied. In the case of a leaf spring or a coil spring, compared with the buffer pad applied for absorbing the swelling of a conventional battery cell, it has the characteristic that even if the deformation of the elastic member due to swelling becomes large, the pressure applied to the battery cell increases more constantly.

[0047] As described above, the present invention has been described with reference to the limited embodiments and the drawings. However, the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made within the equivalent scope of the technical idea and the claims of the present invention by those having ordinary knowledge in the technical field to which the present invention pertains.

Explanation of Reference Numerals

[0048] 1 Battery Pack 10 Battery Modules 20 Pack Tray 30 Module Cover 40 Pack Cover 50 Upper Elastic Member

Claims

1. A plurality of cell stacks, A pack tray for accommodating the plurality of cell stacks, A pack cover for covering the cell stack, An upper elastic member interposed between the uppermost layer of the cell stack and the pack cover, and absorbing the volume expansion due to swelling while being compressed as the uppermost layer of the cell stack moves toward the pack cover due to the swelling of the cell stack, A module cover interposed between the upper elastic member and the uppermost layer of the cell stack, A battery pack including: Each of the cell stacks includes a plurality of battery cells stacked in a horizontal posture along a direction perpendicular to the pack tray, and a partition wall extends between adjacent cell stacks, The module cover and the pack cover are fastened to the pack tray by a first bolt passing through the module cover and the pack cover, The movement of the module cover due to the swelling is guided by the first bolt, Battery pack.

2. The battery pack according to claim 1, wherein the upper elastic member is disposed at a position corresponding to the cell stack.

3. The battery pack according to claim 2, wherein the first bolt is fastened to the partition wall through the pack cover.

4. The pack cover includes a plurality of cover protrusions protruding from an inner surface of the pack cover, The battery pack according to claim 3, wherein the upper elastic member is disposed between a pair of adjacent cover protrusions.

5. The pack cover includes a cover receiving groove formed on an upper surface of the pack cover so that the first bolt is not exposed above the pack cover, The battery pack according to claim 4, wherein the cover receiving groove is formed at a position corresponding to the cover protrusion.

6. The battery pack further includes: A lower elastic member interposed between the pack tray and the lowermost layer of the cell stack, and absorbing the volume expansion due to swelling while being compressed as the lowermost layer of the cell stack moves toward the pack tray due to the swelling of the cell stack.

7. The battery pack according to claim 6, wherein the lower elastic member is disposed at a position corresponding to the cell stack.

8. An automobile including the battery pack according to any one of claims 1 to 7.

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