Battery pack having a structure capable of swelling control and Vehicle including the same

Abstract

A battery pack according to one embodiment of the present invention comprises: a plurality of battery modules; a pack tray accommodating the plurality of battery modules; a module cover covering an opening formed on the upper part of the pack tray; a pack cover covering the module cover; and an upper elastic member interposed between the module cover and the pack cover, which absorbs volume expansion due to swelling while being compressed as the module cover moves toward the pack cover due to swelling of the battery modules.

Description

Technology 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 invention relates to a battery pack having a structure capable of minimizing the amount of swelling occurring along the stacking direction of a cell stack by minimizing the stacking thickness of a single cell stack, and also having a structure capable of increasing the pressure applied to the battery cell relatively consistently as the amount of swelling increases, and an automobile including the same. Background Technology

[0002] In the case of conventional battery packs, to control battery cell swelling, it was common to have a structure in which cushioning pads are inserted between adjacent battery cells and / or at the outermost edge of the cell stack, or a structure in which empty space is secured within the pack housing to account for volume expansion due to battery cell swelling, or a structure in which the pack housing can absorb swelling by deforming according to the swelling of the battery cells.

[0003] In such conventional battery pack structures, as the number of battery cells constituting the cell stack increases, it is required to secure larger empty spaces and / or apply a greater number of buffer pads due to the amount of swelling. In addition, in these conventional structures, the stacking direction of the battery cells is typically parallel to the ground or the bottom surface of the pack housing. This structure has disadvantages in terms of securing structural rigidity and high energy density of the battery pack.

[0004] In addition, when using a cushioning pad to absorb swelling, there was a problem in that the force required to compress the cushioning pad increased as the amount of swelling increased, thereby causing the pressure applied to the battery cell to increase explosively. The problem to be solved

[0005] The present invention is conceived in consideration of the aforementioned problems and has the primary purpose of resolving the decrease in energy density caused by empty spaces for absorbing the volume expansion of battery cells due to swelling, securing the structural rigidity of the battery pack, and preventing the pressure applied to the battery cells from increasing explosively as the amount of swelling increases.

[0006] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by those skilled in the art from the description of the invention below. means of solving the problem

[0007] A battery pack according to one embodiment of the present invention for solving the above-described problem comprises: a plurality of battery modules; a pack tray accommodating the plurality of battery modules; a module cover covering an opening formed on the upper part of the pack tray; a pack cover covering the module cover; and an upper elastic member interposed between the module cover and the pack cover, which absorbs volume expansion due to swelling while being compressed as the module cover moves toward the pack cover due to swelling of the battery modules.

[0008] The battery module may include: a module tray comprising a tray base and a tray partition extending along a direction perpendicular to the tray base to divide a seating 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.

[0009] 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.

[0010] 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.

[0011] The above pack tray may include: a dividing beam that divides the receiving 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 length direction of the pack tray.

[0012] The module cover and the pack cover are fastened to the pack tray by means of bolts penetrating the module cover and the pack cover, and the movement of the module cover due to swelling can be guided by the bolts.

[0013] The above bolt may include: a first bolt that passes through the pack cover and the module cover sequentially and is fastened to the cross beam; and a second bolt that passes through the pack cover and the module cover sequentially and is fastened to the tray bulkhead.

[0014] The above pack cover has a plurality of cover protrusions formed protruding on the 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.

[0015] The above pack cover has a cover receiving groove formed on the upper surface of the pack cover so that the first bolt and the second bolt are not exposed to the upper part of the pack cover, and the cover receiving groove may be formed at a position corresponding to the cover protrusion.

[0016] The battery pack may further include a lower elastic member interposed between the pack tray and the tray base, which absorbs volume expansion due to swelling as the tray base moves toward the pack tray due to swelling of the battery module.

[0017] 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.

[0018] The above tray base can be fastened to the tray bulkhead by a third bolt penetrating the pack tray and the tray base, and the movement of the tray base due to swelling can be guided by the third bolt.

[0019] The above pack tray has a tray protrusion formed protruding on the inner surface of the pack tray, and the first lower elastic member and the second lower elastic member may be disposed between the tray protrusion and the cross beam that are adjacent to each other.

[0020] The above pack tray is provided with a tray receiving groove formed on the lower surface of the pack tray so that the third bolt is not exposed to the lower part of the pack tray, and the tray receiving groove may be formed at a position corresponding to the tray protrusion.

[0022] Meanwhile, an automobile according to one embodiment of the present invention for solving the above-described problem includes a battery pack according to one embodiment of the present invention as described above. Effects of the invention

[0023] According to one aspect of the present invention, the reduction in energy density caused by empty space for absorbing the volume expansion of a battery cell due to swelling is resolved, the structural rigidity of the battery pack is secured, and the pressure applied to the battery cell is prevented from increasing explosively as the amount of swelling increases. Brief explanation of the drawing

[0024] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a drawing showing a battery pack according to one embodiment of the present invention. Figure 2 is an exploded perspective view of the battery pack shown in Figure 1. Figure 3 is a partial enlarged view of Figure 2. FIG. 4 is a drawing showing a battery module of the present invention. FIGS. 5 and 6 are partial cross-sectional views showing a cross-section of a battery pack according to one embodiment of the present invention cut along the AA' line. Specific details for implementing the invention

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention; therefore, it should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing 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 busbar frame assemblies (300).

[0029] The module tray (100) comprises a tray base (110) and a tray partition (120). The tray base (110) supports a cell stack (200) and is positioned on the inner bottom surface of a pack tray (20). The tray partition (120) extends along a direction perpendicular to the tray base (110) and divides the seating space on the tray base (110) along the width direction (a direction parallel to the X-axis) of the tray base (110).

[0030] The cell stack (200) is placed on a 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 placed on the tray base (110) and is positioned on one side of the tray partition (120). The second cell stack (200B) is placed on the tray base (110) and is positioned on the other side of the tray partition (120).

[0031] Each of the first cell stack (200A) and the second cell stack (200B) comprises a plurality of battery cells (210) stacked along a direction perpendicular to the tray base (110). The battery cells (210) may be pouch-type battery cells.

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

[0033] Each of the above pair of busbar frame assemblies (300) includes a busbar frame (310) and a busbar (320). The busbar frame (310) has a lead slit (310a) through which the electrode lead (211) of a battery cell (210) can be drawn out. The busbar (320) is fixed on the busbar frame (310) and can be joined to the electrode lead (211) of each of the plurality of battery cells (210) by welding or the like.

[0035] The above pack tray (20) accommodates a plurality of battery modules (10) in a receiving space formed therein. The above pack tray (20) includes a base plate forming the bottom and a side plate forming the side wall. The above pack tray (20) is equipped with a dividing beam (21) and a plurality of cross beams (22) to divide the receiving space inside and to increase the structural rigidity of the battery pack (1).

[0036] The above-mentioned dividing beam (21) divides the receiving space of the battery module (10) formed inside the pack tray (20) along the width direction (direction parallel to the Y-axis) of the pack tray (20). The above-mentioned cross beam (22) divides the space divided by the dividing beam (21) along the length direction (direction parallel to the X-axis) of the pack tray (20). The above-mentioned cross beam (22) is interposed between each adjacent battery module (10), and is also interposed between a pair of battery modules (10) located at the outermost among a plurality of battery modules (10) arranged along the length direction (direction parallel to the X-axis) of the battery pack (1) and the inner surface of the pack tray (20). Accordingly, a cross beam (22) is located on one side and the other side of the width direction (direction parallel to the X-axis) of all battery modules (10).

[0038] The module cover (30) covers an opening formed on the upper part of the pack tray (20) and faces the battery module (10). The pack cover (40) is positioned on the upper part of 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 volume expansion due to swelling by being compressed as the module cover (30) moves toward the pack cover (40) due to swelling of the battery module (10). The module cover (30) may include a first module cover (30A) that covers battery modules (10) located on one side of the split beam (21) within the battery module (10) receiving space divided by the split beam (21), and a second module cover (30B) that covers battery modules (10) located on the other side. In this way, when multiple module covers (30A, 30B) are provided, the swelling of each of the battery modules (10) housed in different spaces can be controlled individually, so even pressure can be applied to the multiple battery modules (10).

[0039] The upper elastic member (50) may include a first upper elastic member (50A) positioned at a location corresponding to the first cell stack (200A) and a second upper elastic member (50B) positioned at a location corresponding to the second cell stack (200B). Thus, the battery pack (1) according to one embodiment of the present invention has a structure that can individually control swelling for each battery module (10) and also individually control swelling for each of the first cell stack (200A) and the second cell stack (200B).

[0041] The module cover (30) and pack cover (40) are fastened to the pack tray (20) by bolts penetrating the module cover (30) and pack cover (40). The movement of the module cover (30) due to swelling can be guided by the bolt (B). The bolt includes a first bolt (B1) which is fastened to the cross beam (22) by sequentially penetrating the pack cover (40) and module cover (30) from the top, and a second bolt (B2) which is fastened to the tray partition (120) by sequentially penetrating the pack cover (40) and module cover (30) from the top.

[0042] The pack cover (40) may have a plurality of cover protrusions (40a) formed protruding on 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 positioned between a pair of adjacent cover protrusions (40a), and the cover protrusions (40a) may function as stoppers to prevent the first upper elastic member (50A) and the second upper elastic member (50B) from deviating from a predetermined position. The cover protrusions (40a) may have a shape that extends long along the width direction (a direction parallel to the Y-axis) of the pack cover (40). The first bolt (B1) and the second bolt (B2) penetrate the cover protrusions (40a).

[0043] The above pack cover (40) may be provided with 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 to the upper surface of 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).

[0045] Referring to FIG. 6 together with FIG. 1 to 4, 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). The lower elastic member (60) absorbs volume expansion due to swelling as it is compressed as the tray base (110) moves toward the base plate of the pack tray (20) due to swelling of the battery module (10).

[0046] The lower elastic member (60) may include a first lower elastic member (60A) positioned at a location corresponding to the first cell stack (200A) and a second lower elastic member (60B) positioned at a location corresponding to the second cell stack (200B).

[0047] The above tray base (110) is fastened to the tray partition by a third bolt (B3) that penetrates the pack tray (20) and the tray base (110). The movement of the above tray base (110) due to swelling can be guided by the third bolt (B3).

[0048] The above pack tray (20) may be provided with a tray protrusion (20a) formed protruding on 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 positioned between adjacent tray protrusions (20a) and cross beams (22). The tray protrusions (20a) and cross beams (22) can function as stoppers to prevent the first lower elastic member (60A) and the second lower elastic member (60B) from deviating from a predetermined position. The third bolt (B3) penetrates the tray protrusion (20a).

[0049] The above pack tray (20) may be provided with 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 to the lower part of 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).

[0050] Meanwhile, for the upper elastic member (50) and lower elastic member (60), for example, a leaf spring or a coil spring may be applied. In the case of a leaf spring or a coil spring, compared to a cushioning pad conventionally applied to absorb swelling of a battery cell, the increase in pressure applied to the battery cell due to the deformation of the elastic member caused by swelling has a more consistent characteristic.

[0052] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols

[0053] 1: Battery pack 10: Battery module 100: Module Tray 110: Tray Base 120: Tray bulkhead 200: Cell stack 200A: First cell stack 200B: Second cell stack 210: Battery cell 211: Electrode Lead 300: Busbar frame assembly 310: Busbar frame 310a: Lead slit 320: Busbar 20: Pack Tray 20a: Tray protrusion 20b: Tray receiving groove 21: Split beam 22: Cross Beam 30: Module Cover 40: Pack Cover 40a: Cover protrusion 40B: Cover receiving groove 50: Upper elastic member 50A: First upper elastic member 50B: Second upper elastic member 60: Lower elastic member 60A: First lower elastic member 60B: Second lower elastic member B1: 1st bolt B2: Second Bolt B3: Third Bolt

Claims

Claim 1 A battery pack comprising: a plurality of battery modules formed by stacking a plurality of battery cells; a pack tray accommodating the plurality of battery modules; a module cover covering an opening formed on the upper part of the pack tray; a pack cover covering the module cover; and an upper elastic member interposed between the module cover and the pack cover, which absorbs volume expansion due to swelling while being compressed as the module cover moves toward the pack cover due to swelling of the battery modules, and which is arranged parallel to a direction perpendicular to the stacking direction of the plurality of battery cells. Claim 2 A battery pack according to claim 1, wherein the battery module comprises: a module tray including a tray base and a tray partition extending along a direction perpendicular to the tray base and dividing a seating space on the tray base along the width direction of the tray base; a first cell stack disposed on the tray base and disposed on one side of the tray partition; and a second cell stack disposed on the tray base and disposed on the other side of the tray partition. Claim 3 A battery pack according to claim 2, wherein the upper elastic member comprises: 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. Claim 4 A battery pack according to paragraph 2, wherein each of the first cell stack and the second cell stack comprises a plurality of battery cells stacked along a direction perpendicular to the tray base. Claim 5 A battery pack according to paragraph 3, wherein the pack tray comprises: a dividing beam that divides the receiving 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 length direction of the pack tray. Claim 6 A battery pack according to claim 5, wherein the module cover and the pack cover are fastened to the pack tray by a bolt penetrating the module cover and the pack cover, and the movement of the module cover due to swelling is guided by the bolt. Claim 7 A battery pack according to claim 6, characterized in that the bolt comprises: a first bolt that sequentially penetrates the pack cover and the module cover and is fastened to the cross beam; and a second bolt that sequentially penetrates the pack cover and the module cover and is fastened to the tray partition. Claim 8 A battery pack according to claim 7, wherein the pack cover has a plurality of cover protrusions formed protruding on the inner surface of the pack cover, and the first upper elastic member and the second upper elastic member are disposed between a pair of adjacent cover protrusions. Claim 9 A battery pack according to claim 8, wherein the pack cover has a cover receiving groove formed on the upper surface of the pack cover so as not to expose the first bolt and the second bolt to the upper surface of the pack cover, and the cover receiving groove is formed at a position corresponding to the cover protrusion. Claim 10 A battery pack according to claim 5, wherein the battery pack further comprises a lower elastic member interposed between the pack tray and the tray base, which 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. Claim 11 A battery pack according to claim 10, wherein the lower elastic member comprises: 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. Claim 12 A battery pack according to claim 11, wherein the tray base is fastened to the tray partition by a third bolt penetrating the pack tray and the tray base, and the movement of the tray base due to swelling is guided by the third bolt. Claim 13 A battery pack according to claim 12, wherein the pack tray has a tray protrusion formed protruding on the inner surface of the pack tray, and the first lower elastic member and the second lower elastic member are disposed between the tray protrusion and the cross beam that are adjacent to each other. Claim 14 A battery pack according to claim 13, wherein the pack tray has a tray receiving groove formed on the lower surface of the pack tray so as not to expose the third bolt to the lower part of the pack tray, and the tray receiving groove is formed at a position corresponding to the tray protrusion. Claim 15 An automobile comprising a battery pack according to any one of paragraphs 1 through 14.

Images