Cell stack assembly and battery pack including same

Abstract

The present invention relates to a cell stack assembly and a battery pack including the same. The cell stack assembly of the present invention includes a cell stack in which a plurality of battery cells are stacked, each having an electrode lead extending from one or both sides thereof, and a separator provided to contact one side of at least one battery cell in the cell stack, the separator including a hollow portion therein and protrusions on both side surfaces thereof.

Description

[Technical Field]

[0001] The present invention relates to a cell stack assembly and a battery pack including the same. The cell stack assembly of the present invention includes a separator having a hollow interior and protrusions on both sides. The battery pack of the present invention including the cell stack assembly is characterized in that the separator applied to each cell stack assembly suppresses heat transfer in various ways.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0016354, filed February 7, 2023, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Currently widely used types of secondary batteries include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, and nickel zinc batteries. The operating voltage of such a unit secondary battery cell, i.e., a unit battery cell, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, a battery pack may be configured by connecting a plurality of battery cells in series. Alternatively, a battery pack may be configured by connecting a number of battery cells in parallel depending on the required charge / discharge capacity of the battery pack. Therefore, the number of battery cells included in the battery pack may be variously set depending on the required output voltage or charge / discharge capacity.

[0004] When constructing a battery pack by connecting a plurality of battery cells in series / parallel, a common method is to first construct a battery module including at least one battery cell, and then use this at least one battery module to add other components to construct the battery pack.

[0005] A conventional battery module generally includes at least one cell stack containing battery cells, and a box-shaped metal housing structure, i.e., a module frame, that houses the at least one cell stack.

[0006] In addition, to solve the problem of the weight and volume of the module frame itself reducing the energy density of the entire battery pack and increasing the weight of the entire battery pack, a cell stack assembly that does not have a module frame configuration that surrounds and protects the cell stack may be used instead of a conventional battery module.

[0007] Fig. 1 is a perspective view of a conventional cell stack assembly 60 that does not include a module frame. Referring to Fig. 1, a plurality of battery cells 10 are stacked in a row to form a cell stack 20, and bus bar frames 30 including bus bars connected to the electrode leads of each cell are attached to the front and rear surfaces of the cell stack 20. Also shown are end plates 40 that are attached to the bus bar frame 30 to protect the electrode leads and bus bars.

[0008] 2 shows the cell stack assembly 60 of FIG. 1, which is provided with support beams 50 capable of supporting and protecting the cell stacks 20. Referring to FIG. 2, the support beams 50 are provided on both sides of the cell stacks 20 to support each cell stack 20 while simultaneously protecting the cell stacks 20 from external impacts.

[0009] FIG. 3 shows a pack case 70 included in a conventional battery pack in which the cell stack assembly 60 of FIG. 2 is housed.

[0010] When a cell stack assembly 60 including a support beam 50 is housed in a pack case 70 having the structure shown in Figure 3, the support beam 50 can adequately separate and protect a pair of adjacent cell stacks 20.

[0011] However, the support beams 50 of each cell stack assembly 60 smoothly transfer heat with the support beams 50 of other adjacent cell stack assemblies 60, and if thermal runaway occurs in any one cell stack 20, there is no way to prevent high-temperature heat from being transferred to the other cell stacks 20.

[0012] In addition, since the cells included in the cell stack assembly 60 are stacked together under pressure so that they are in contact with each other to form a single cell stack 20, there is a problem that if thermal runaway occurs in one cell within the cell stack assembly 60, there is no way to prevent high-temperature heat from being transferred to other cells. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Korean Patent Publication No. 10-2022-0014027 Summary of the Invention [Problem to be solved by the invention]

[0014] Therefore, an object of the present invention is to provide a cell stack assembly having a structure capable of suppressing heat transfer that occurs in various forms, and a battery pack including the same.

[0015] Another object of the present invention is to provide a cell stack assembly that is lightweight while employing a separation member that suppresses heat transfer, and a battery pack including the same.

[0016] Other objects and advantages of the present invention will become apparent from the following description and become more clearly apparent from the embodiments of the present invention. Also, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0017] According to the present invention, there is provided a cell stack assembly including: a cell stack in which a plurality of battery cells are stacked, each having an electrode lead extending from one or both sides; and a separator member provided to contact one side of at least one battery cell in the cell stack, wherein the separator member includes a hollow portion therein and protrusions on both side surfaces.

[0018] At least one of an outer surface and an inner surface of the separating member may be coated with a thin metal film.

[0019] The protrusions may form any one of a dot pattern, a stripe pattern, a lattice pattern, and a honeycomb pattern.

[0020] The separating member includes a first support portion and a second support portion that respectively connect the upper and lower ends of both sides including the protrusion, and the thickness of the first support portion and the second support portion may be increased toward the edge.

[0021] The separating member may include any one of glass and stainless steel.

[0022] The separating members may be attached to both sides of the cell stack.

[0023] According to the present invention, there is provided a battery pack including a pack case that houses the above-mentioned cell stack assembly, the pack case including a base plate that supports a lower portion of the cell stack assembly, and a side wall that is coupled to an edge of the base plate to support a side of the cell stack assembly.

[0024] At least one of an outer surface and an inner surface of the separating member may be coated with a thin metal film.

[0025] The protrusions may form any one of a dot pattern, a stripe pattern, a lattice pattern, and a honeycomb pattern.

[0026] The separating member includes a first support portion and a second support portion that respectively connect the upper and lower ends of both sides including the protrusion, and the thickness of the first support portion and the second support portion may be increased toward the edge.

[0027] The separating member may include any one of glass and stainless steel.

[0028] At least one of an outer surface and an inner surface of the separating member may be coated with a thin metal film.

[0029] The separating members may be attached to both sides of the cell stack.

[0030] The pack case may further include a partition wall coupled to the base plate and interposed between any pair of adjacently arranged cell stack assemblies to separate them. [Effects of the Invention]

[0031] According to the present invention, the thermal safety of the cell stack assembly and the battery pack can be improved.

[0032] Furthermore, the present invention can reduce the weight of the cell stack assembly and the battery pack, thereby improving the energy density. [Brief explanation of the drawings]

[0033] [Figure 1] 1 shows a conventional cell stack assembly. [Figure 2] 1 shows a conventional cell stack assembly equipped with support beams. [Figure 3] 1 shows a conventional battery pack. [Figure 4] 1 is a perspective view of a cell stack assembly according to a first embodiment of the present invention. [Figure 5]10 shows another embodiment of a cell stack assembly in which a module frame surrounding the cell stack is applied. [Figure 6] 2 is a perspective view of a separation member included in the cell stack assembly according to the first embodiment of the present invention. FIG. [Figure 7] FIG. 7 is a vertical cross-sectional perspective view of FIG. 6. [Figure 8] FIG. 7 is a cross-sectional perspective view of FIG. 6. [Figure 9] 8A and 8B are enlarged views of the upper and lower ends of the separating member of FIG. 7. [Figure 10] This shows that heat is transferred through a separating member whose outer surface is coated with a thin metal film. [Figure 11] This shows that heat is transferred through a separating member whose inner surface is coated with a thin metal film. [Figure 12] 1 is a perspective view of a pack case included in a battery pack in which a cell stack assembly according to a first embodiment of the present invention is housed; [Figure 13] FIG. 10 is a vertical cross-sectional perspective view of a separation member included in a cell stack assembly according to a second embodiment of the present invention. [Figure 14] FIG. 10 is a cross-sectional perspective view of a separation member included in a cell stack assembly according to a second embodiment of the present invention. [Figure 15] 14 shows an enlarged view of the upper and lower ends of the separating member of FIG. 13. [Figure 16] FIG. 10 is a perspective view of a cell stack assembly according to a third embodiment of the present invention. [Figure 17] FIG. 10 is a perspective view of a pack case included in a battery pack accommodating a cell stack assembly according to a third embodiment of the present invention. [Figure 18] 10 is a perspective view of a separation member included in a cell stack assembly according to a fourth embodiment of the present invention. [Figure 19] 10 is a perspective view of a separation member included in a cell stack assembly according to a fifth embodiment of the present invention. [Figure 20]13 is a perspective view of a separation member included in a cell stack assembly according to a sixth embodiment of the present invention. [Figure 21] 13 is a perspective view of a separation member included in a cell stack assembly according to a seventh embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before that, the terms and words used in the specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concepts of the terms to best describe his own invention.

[0035] Therefore, 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 the entire technical idea of ​​the present invention, and there may be various equivalents and modifications that can replace them at the time of this application.

[0036] Furthermore, in the description of the present invention, if it is determined that a detailed description of related publicly known structures or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0037] The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and therefore the shapes and sizes of components in the drawings may be exaggerated, omitted, or shown in a schematic manner for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0038] The present invention relates to a cell stack assembly 100 and a battery pack including the same. The cell stack assembly 100 of the present invention includes a separator 140 having a hollow interior and protrusions 141 on both sides. The battery pack of the present invention including the cell stack assembly 100 is characterized in that the separator 140 applied to each cell stack assembly 100 suppresses the transfer of heat H in various ways.

[0039] Figures 4 to 12 relate to a cell stack assembly 100 according to a first embodiment of the present invention and a battery pack including the same, Figures 13 to 15 relate to a cell stack assembly 100 according to a second embodiment, Figures 16 to 17 relate to a cell stack assembly 100 according to a third embodiment of the present invention and a battery pack including the same, and Figures 18 to 21 relate to cell stack assemblies 100 according to fourth to seventh embodiments of the present invention, respectively.

[0040] Hereinafter, a cell stack assembly 100 and a battery pack according to various embodiments of the present invention will be described with reference to the above drawings.

[0041] (First embodiment) Cell stack assembly 100

[0042] FIG. 4 is a perspective view of a cell stack assembly 100 according to the first embodiment of the present invention.

[0043] 4, the cell stack assembly 100 includes a cell stack 110 and a separation member 140. More specifically, the cell stack assembly 100 includes a cell stack 110 in which a plurality of battery cells 111, each having an electrode lead (not shown) extending from one or both sides thereof, are stacked in one direction, bus bar frames 120 each including a bus bar 121 electrically connected to each electrode lead of the cell stack 110 and coupled to a front and rear surface of the cell stack 110, end plates 130 coupled to the bus bar frame 120 to cover the bus bar 121, and a separation member 140 provided to contact one side of at least one battery cell 111 in the cell stack 110.

[0044] The cell stack assembly 100 of the present invention may have a structure in which the internal cells 111 and separators 140 are exposed to the outside, as shown in Figure 4 above, but it may also have a structure in which the cells 111 and separators 140 are sealed and not exposed to the outside.

[0045] FIG. 5 shows a cell stack assembly 100 according to another embodiment of the present invention, in which a module frame 150 surrounding a cell stack 110 is applied.

[0046] The module frame 150 surrounds and covers the cell stack 110, and is coupled to the module frame 150 or end plates 130 to protect each cell 111 from the outside.

[0047] The separating member 140 is inserted between any pair of cells 111 among the plurality of cells 111 included in the cell stack 110, as shown in FIG.

[0048] As described above, the separating members 140 interposed between the cells 111 separate the cells 111, thereby blocking the transfer of heat H between the cells 111. That is, when one of the cells 111 experiences thermal runaway and releases high-temperature heat H, the separating members 140 prevent the heat H from being transferred to other adjacent cells 111.

[0049] FIG. 6 is a perspective view of a separation member 140 included in the cell stack assembly 100 according to the first embodiment of the present invention.

[0050] The separating member 140 may be made of glass, which has low thermal conductivity, or stainless steel, but any material that is highly safe against high temperatures (H) can be used.

[0051] The separator 140 of the present invention is characterized by effectively blocking the transfer of heat H that occurs in various ways, such as conduction, convection, and radiation.

[0052] As shown in FIG. 6, the separating member 140 includes protrusions 141 protruding in a predetermined pattern on both sides.

[0053] The protrusions 141 have the effect of reducing the contact area with the cells 111 and narrowing the path through which heat H is transferred from the cells 111 to the separating member 140 .

[0054] The separating member 140 also has improved structural stability since the protrusions 141 have a stable pattern shape.

[0055] 7 and 8 are cross-sectional perspective views of the separating member 140 of Fig. 6. Specifically, Fig. 7 shows a cross section taken along line A-A'' of Fig. 6, and Fig. 8 shows a cross section taken along line B-B'' of Fig. 6.

[0056] 7 and 8, the separating member 140 has a hollow structure with an open interior. That is, the separating member 140 includes a hollow portion 142 therein.

[0057] The hollow portion 142 of the separating member 140 maintains a vacuum state.

[0058] The separation member 140 effectively blocks the transfer of heat H that occurs in the form of conduction and convection inside the separation member 140 due to the hollow portion 142 and the vacuum structure of the hollow portion 142 .

[0059] The separating member 140 includes a first support portion 140a and a second support portion 140b that respectively connect the upper and lower ends of both sides including the protrusion 141, and a third support portion and a fourth support portion that respectively connect the side ends of both sides.

[0060] FIG. 9 shows an enlarged view of the upper end (FIG. 9(a)) and the lower end (FIG. 9(b)) of the separating member 140 of FIG.

[0061] 9, the heat H transferred to one side of the separating member 140 moves to the other side in a conductive form via the first supporting portion 140a corresponding to the upper end of the separating member 140 and the second supporting portion 140b corresponding to the lower end of the separating member 140. Although not shown, the third supporting portion and the fourth supporting portion also serve as the only paths through which the heat H is transferred by conduction, just like the first supporting portion 140a and the second supporting portion 140b.

[0062] The outer surface of the separating member 140 may be coated with a thin metal film capable of reflecting radiant heat H. That is, the thin metal film reflects the heat H that moves in the form of radiation, so that only a portion of the heat H is transferred to the separating member 140.

[0063] FIG. 10 is a simplified illustration showing that heat H is transferred through a separating member 140 having a thin metal film coated on its outer surface.

[0064] 10, it can be seen that the heat H moving in a radiant form toward the separating member 140 is partially reflected on the surface of the separating member 140 and not absorbed, but is only partially absorbed by the separating member 140.

[0065] The metal thin film can be coated not only on the outer surface of the separating member 140 but also on the inner surface where the hollow portion 142 is located.

[0066] FIG. 11 above simply shows that heat H is transferred through a separating member 140 having an inner surface coated with a thin metal film.

[0067] 11, it can be seen that the heat H moving in the form of radiation toward the separating member 140 is absorbed by the surface of the separating member 140, and the heat H radiated through the hollow portion 142 is partially reflected by the thin metal film coated on the inner surface.

[0068] Battery pack

[0069] FIG. 12 is a perspective view of a pack case 1000 included in a battery pack in which a cell stack assembly 100 according to the first embodiment of the present invention is housed.

[0070] The pack case 1000 includes a base plate 1100 and a side wall 1200. Specifically, as shown in FIG. 12 , the pack case 1000 includes the base plate 1100 that supports the lower part of the cell stack assembly 100, and the side wall 1200 that is coupled to the edge of the base plate 1100 so as to support the side of the cell stack assembly 100.

[0071] The pack case 1000 further includes a plurality of partition walls 1300 coupled to the base plate 1100 so as to separate a pair of adjacently arranged cell stack assemblies 100 from each other.

[0072] The partition walls 1300 serve to separate the cell stack assemblies 100 and to block the transfer of heat H between them.

[0073] In the battery pack, since a separation member 140 is applied to each cell stack assembly 100 contained therein, even if a thermal H runaway phenomenon occurs in any one cell stack assembly 100, the phenomenon of high-temperature heat H being transferred to the entire cell stack assembly 100 can be delayed.

[0074] (Second embodiment) Cell stack assembly 100

[0075] 13 and 14 are cross-sectional perspective views of a separation member 140 included in a cell stack assembly 100 according to the second embodiment.

[0076] The thicknesses of the first support portion 140a, the second support portion 140b, the third support portion, and the fourth support portion of the separating member 140 become thicker toward the edges and thinner toward the center. That is, the thicknesses of the first to fourth support portions connecting both side surfaces of the separating member 140 including the protrusion 141 are thinner than the thicknesses of the first to fourth support portions of the separating member 140 of the cell stack assembly 100 according to the first embodiment. Therefore, the transfer of heat H through the first to fourth support portions can be restricted, and in particular, the amount of heat H transferred by conduction can be significantly reduced.

[0077] FIG. 15 shows an enlarged view of the upper end (FIG. 15(a)) and the lower end (FIG. 15(b)) of the separating member 140 of FIG.

[0078] 15, the heat H transferred to one side of the separating member 140 moves to the other side in a conductive form via the first supporting portion 140a corresponding to the upper end of the separating member 140 and the second supporting portion 140b corresponding to the lower end thereof. Although not shown, the third supporting portion and the fourth supporting portion also serve as the only path through which the heat H moves by conduction in the same manner as the first supporting portion 140a and the second supporting portion 140b.

[0079] However, as shown in FIG. 15, the thickness of the first support portion 140a and the second support portion 140b connecting both sides of the separation member 140 is reduced, so the amount of heat H that moves may decrease.

[0080] (Third embodiment) Cell stack assembly 100

[0081] FIG. 16 is a perspective view of a cell stack assembly 100 according to a third embodiment of the present invention.

[0082] 16, the cell stack assembly 100 includes a cell stack 110 and a separator 140. More specifically, as shown in FIG. 16, the cell stack assembly 100 includes a cell stack 110 in which a plurality of battery cells 111, each having an electrode lead (not shown) extending from one or both sides thereof, are stacked in one direction, bus bar frames 120 each including a bus bar 121 electrically connected to each electrode lead of the cell stack 110 and coupled to the front and rear surfaces of the cell stack 110, end plates 130 coupled to the bus bar frame 120 to cover the bus bar 121, and separators 140 provided on both sides of the cell stack 110 to contact one side of the outermost cell, respectively.

[0083] The cell stack assembly 100 of the present invention may have a structure in which the internal cells 111 and separation members 140 are exposed to the outside, as shown in Figure 16 above, but it may also have a structure in which the cells 111 and separation members 140 are sealed and not exposed to the outside.

[0084] 16, the separation members 140 are provided on both sides of the cell stack 110 to contact the outer surfaces of the outermost cells 111. In this case, the separation members 140 may be coupled to and fixed to the bus bar frame 120.

[0085] As described above, the separating member 140 attached to one side of the outermost cell 111 of the cell stack 110 serves to support both sides of the cell stack 110 and to prevent heat H from being released to the outside from inside the cell stack 110. That is, when the cell stack 110 experiences thermal runaway and releases high-temperature heat H, the separating member 140 serves to prevent the heat H from being transferred to other adjacent cell stacks 110.

[0086] Battery pack

[0087] FIG. 17 is a perspective view of a pack case 1000 included in a battery pack in which a cell stack assembly 100 according to a third embodiment of the present invention is housed.

[0088] The pack case 1000 includes a base plate 1100 and a side wall 1200. Specifically, as shown in FIG. 17 , the pack case 1000 includes the base plate 1100 that supports the lower part of the cell stack assembly 100, and the side wall 1200 that is coupled to the edge of the base plate 1100 so as to support the side of the cell stack assembly 100.

[0089] A pair of cell stacks 110 arranged adjacent to each other in the pack case 1000 have separation members 140 provided on both sides of each cell stack 110. In other words, two separation members 140 are in contact with each other between the pair of cell stacks 110.

[0090] The separating members 140 separate the cell stacks 110 and prevent heat H from being transferred from one cell stack 110 to another adjacent cell stack 110.

[0091] In the battery pack, since a separation member 140 is applied to each cell stack assembly 100 contained therein, even if a thermal H runaway phenomenon occurs in any one cell stack assembly 100, the phenomenon of high-temperature heat H being transferred to the entire cell stack assembly 100 can be delayed.

[0092] (Fourth embodiment) Cell stack assembly 100

[0093] FIG. 18 is a perspective view of a separation member 140 included in a cell stack assembly 100 according to a fourth embodiment of the present invention.

[0094] The separating member 140 of the present invention may have protrusions 141 formed in various patterns, and may have a dot pattern as shown in FIG.

[0095] (Fifth embodiment) Cell stack assembly 100

[0096] FIG. 19 is a perspective view of a separation member 140 included in a cell stack assembly 100 according to a fifth embodiment of the present invention.

[0097] The separating member 140 of the present invention may have protrusions 141 formed in various patterns, and may have a grid pattern as shown in FIG.

[0098] (Sixth embodiment) Cell stack assembly 100

[0099] FIG. 20 is a perspective view of a separation member 140 included in a cell stack assembly 100 according to a sixth embodiment of the present invention.

[0100] The separating member 140 of the present invention may have protrusions 141 formed in various patterns, and may have a stripe pattern as shown in Fig. 20. In this case, the protrusions 141 extend along the height direction of the separating member 140 and are spaced apart at predetermined intervals along the longitudinal direction of the separating member 140.

[0101] (Seventh embodiment) Cell stack assembly 100

[0102] FIG. 21 is a perspective view of a separation member 140 included in a cell stack assembly 100 according to a seventh embodiment of the present invention.

[0103] The separating member 140 of the present invention may have various patterns of protrusions 141, and may have a stripe pattern as shown in Fig. 21. In this case, the protrusions 141 extend along the length of the separating member 140 and are spaced apart at predetermined intervals along the height of the separating member 140.

[0104] The present invention has been described in more detail above through the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore, there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0105] 10: (Prior Art) Battery Cell 20: (Conventional technology) Cell stack 30: (Prior Art) Busbar Frame 40: (Prior Art) End Plate 50: (Prior Art) Support beam 60: (Prior Art) Cell stack assembly 70: (Conventional technology) Pack case 100: Cell stack assembly 110: Cell stack 111: Cell 120: Busbar frame 121: Busbar 130: End plate 140: Separation member 140a: First support part 140b: Second support part 141:Protrusion 142:Hollow part 150:Module frame 1000: Pack case 1100: Base plate 1200: Side wall 1300: Bulkhead H: Heat

Claims

1. a cell stack in which a plurality of battery cells each having an electrode lead led out from one side or both sides are stacked; a separator member provided to contact one side of at least one battery cell of the cell stack, The separating member is A cell stack assembly including a hollow portion therein and protrusions on both side surfaces.

2. The cell stack assembly according to claim 1 , wherein at least one of the outer and inner surfaces of the separator is coated with a thin metal film.

3. The cell stack assembly according to claim 1 , wherein the protrusions form one of a dot pattern, a stripe pattern, a grid pattern, and a honeycomb pattern.

4. the separating member includes a first support portion and a second support portion that respectively connect upper and lower ends of both side surfaces including the protrusion, The cell stack assembly according to claim 1 , wherein the thickness of the first support portion and the second support portion increases toward the edge.

5. The cell stack assembly according to claim 1 , wherein the separating member includes one of glass and stainless steel.

6. The cell stack assembly according to claim 1 , wherein the separating members are attached to both side surfaces of the cell stack.

7. a pack case that houses the cell stack assembly according to claim 1; The pack case is a base plate supporting a lower portion of the cell stack assembly; a sidewall coupled to an edge of the base plate to support a side of the cell stack assembly.

8. The battery pack according to claim 7 , wherein at least one of an outer surface and an inner surface of the separating member is coated with a thin metal film.

9. The battery pack of claim 7 , wherein the protrusions form one of a dot pattern, a stripe pattern, a lattice pattern, and a honeycomb pattern.

10. the separating member includes a first support portion and a second support portion that respectively connect upper and lower ends of both side surfaces including the protrusion, The battery pack according to claim 7 , wherein the thickness of the first support portion and the second support portion increases toward the edge.

11. The battery pack according to claim 7 , wherein the separating member includes one of glass and stainless steel.

12. The battery pack according to claim 7 , wherein at least one of an outer surface and an inner surface of the separating member is coated with a thin metal film.

13. The battery pack according to claim 7 , wherein the separators are attached to both sides of the cell stack.

14. 8. The battery pack according to claim 7, wherein the pack case further includes a partition wall coupled to the base plate and interposed between any pair of adjacently arranged cell stack assemblies to separate them.

Images