Cell case, battery cell and battery module

Abstract

A cell case according to an embodiment of the present invention can accommodate an electrode assembly connected to an electrode tab. The cell case comprises: a cup portion recessed to form a receiving space in which the electrode assembly is accommodated; and a pressurizing portion provided in the cup portion to face an edge region adjacent to the electrode tab of the accommodated electrode assembly, configured to pressurize the edge region, wherein the pressurizing portion may include an inlet configured to form an internal space and configured to allow gas to flow from the receiving space into the internal space.

Description

Technology Field

[0001] The present invention relates to a cell case, a battery cell, and a battery module for improving surface pressure imbalance applied to a battery cell. Background Technology

[0002] With the technological development and increasing demand for electric vehicles and mobile devices, the demand for secondary batteries as an energy source is rising. Unlike primary batteries, secondary batteries can be reused through charging even after a single use. A secondary battery consists of a positive electrode and a negative electrode. When a metal is oxidized at the positive electrode, electricity is generated by the movement of electrons emitted from the metal. The metal oxidized at the positive electrode moves through the electrolyte to the negative electrode and is reduced.

[0003] To manufacture such a secondary battery, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to produce a positive electrode and a negative electrode, and an electrode assembly is formed by stacking them on both sides of a separator. Then, the electrode assembly is housed in a case, and after injecting an electrolyte, it is sealed.

[0004] Secondary batteries are classified into pouch type and can type depending on the material of the case housing the electrode assembly. Pouch-type secondary batteries are formed by housing an electrode assembly in a pouch made of a flexible polymer material. Can-type secondary batteries, on the other hand, are formed by housing an electrode assembly in a case made of materials such as metal or plastic.

[0005] A pouch, which is a case for a pouch-type secondary battery, is manufactured by performing press processing on a flexible pouch film to form a cup portion. Once the cup portion is formed, an electrode assembly is housed in the electrode receiving space of the cup portion, and the pouch is sealed by fusing the edges of the cup portion to form a side portion.

[0006] Furthermore, a battery module is manufactured by arranging multiple such secondary batteries, i.e., battery cells, and housing them in a housing. Additionally, a battery pack may be manufactured by combining multiple battery modules or housing multiple battery modules in a separate housing.

[0007] Meanwhile, as charging and discharging proceed, a swelling phenomenon occurs in which the volume of the battery cells expands. When battery cells swell due to this swelling, an imbalance in surface pressure occurs between the battery cells within the battery module.

[0008] In particular, this surface pressure imbalance phenomenon may result from thickness variations occurring in the center and edge regions of the electrode assembly due to the stacked structure of the electrode assembly and the structure for electrical connection.

[0009] Furthermore, imbalances in surface pressure applied to battery cells cause problems that reduce the lifespan of battery cells and battery modules. Moreover, this can lead to so-called "sudden drop" phenomena, such as a rapid decrease in battery cell capacity or a sudden increase in resistance. The problem to be solved

[0010] One problem that the present invention aims to solve is to provide a cell case, a battery cell, and a battery module that improve surface pressure imbalance applied to a battery cell by providing a pressure member for applying pressure to the edge area of ​​an electrode assembly in the cup portion of the cell case. means of solving the problem

[0011] A cell case according to an embodiment of the present invention can accommodate an electrode assembly connected to an electrode tab. The cell case comprises: a cup portion recessed to form a receiving space in which the electrode assembly is accommodated; and a pressurizing portion provided in the cup portion to face an edge region adjacent to the electrode tab of the accommodated electrode assembly, configured to pressurize the edge region, wherein the pressurizing portion may include an inlet configured to form an internal space and configured to allow gas to flow from the receiving space into the internal space.

[0012] The volume of the internal space of the above pressurizing part can be varied by the inflow of gas.

[0013] The above-mentioned pressure part may protrude from the inner surface of the cup part with respect to the depth direction of the cup part.

[0014] The above-mentioned pressure member may face at least one of the two sides of the edge region of the above-mentioned electrode assembly.

[0015] The above-mentioned pressurizing member may include a coupling surface coupled to the cup portion; a pressurizing surface facing the edge region of the received electrode assembly; and a connecting surface connecting the coupling surface and the pressurizing surface, wherein the inlet is provided.

[0016] The above inlet may include a valve that moves gas by the pressure difference between the internal pressure of the receiving space and the internal pressure of the internal space.

[0017] The above valve can be configured to allow gas to pass through while blocking the passage of liquid.

[0018] The above valve may protrude from the end of the electrode assembly.

[0019] The above pressurizing unit may further include an electrolyte contained in the internal space.

[0020] The cell case may be configured such that the electrode tabs are connected to each side of the electrode assembly, and the pressurizing part is provided in the cup portion to face the edge regions located on each side of the received electrode assembly.

[0021] The length of the above-mentioned pressure part may correspond to the width of the above-mentioned electrode assembly.

[0022] The ratio of the width of the above-mentioned pressurizing part to the length of the above-mentioned electrode assembly may be 0.12 or more and 0.16 or less.

[0023] The above cup portions are formed as a pair spaced apart from each other when the cell case is unfolded, and the above pressurizing portions may be provided in each of the pair of cup portions.

[0024] A battery cell according to an embodiment of the present invention comprises: an electrode assembly connected to an electrode tab; and a cell case that accommodates the electrode assembly and an electrolyte. The cell case comprises: a cup portion recessed to form a receiving space in which the electrode assembly is accommodated; and a pressurizing portion provided in the cup portion to face an edge region adjacent to the electrode tab of the accommodated electrode assembly, and configured to pressurize the edge region. The pressurizing portion may include an inlet configured to form an internal space and configured to allow gas to flow from the receiving space into the internal space.

[0025] A battery module according to an embodiment of the present invention comprises: a housing; and a plurality of battery cells electrically connected and disposed adjacently to each other within the housing, wherein at least one of the plurality of battery cells comprises: an electrode assembly connected to an electrode tab; and a cell case that accommodates the electrode assembly and an electrolyte, wherein the cell case comprises: a cup portion recessed to form a receiving space in which the electrode assembly is accommodated; and a pressurizing portion provided in the cup portion to face an edge region adjacent to the electrode tab of the accommodated electrode assembly, and configured to pressurize the edge region, wherein the pressurizing portion may include an inlet configured to form an internal space and configured to allow gas to flow from the receiving space into the internal space. Effects of the invention

[0026] According to a preferred embodiment of the present invention, a pressure member for applying pressure to the edge area of ​​an electrode assembly is provided in the cup portion of a cell case, thereby improving the surface pressure imbalance applied to the battery cell.

[0027] In addition, as charging and discharging proceed, gas flows into the internal space of the pressurizing part, and through a structure in which the pressurizing part expands, the surface pressure imbalance applied to the battery cell can be improved more efficiently.

[0028] In addition, by improving the surface pressure applied to the battery cell, the lifespan of the battery cell and battery module can be increased, and sudden drop phenomena, such as a rapid decrease in battery cell capacity or a rapid increase in resistance, can be improved.

[0029] In addition to this, the configurations according to the preferred embodiments of the present invention may include effects that are easily predictable by those skilled in the art. Brief explanation of the drawing

[0030] 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 schematic diagram illustrating the interior of a battery module according to one embodiment of the present invention. FIG. 2 is an assembly diagram of a battery cell according to one embodiment of the present invention. FIG. 3 is a drawing of a cell case in an unfolded state according to one embodiment of the present invention. Figure 4 is a drawing showing a part of the AA' cross-section of Figure 3. FIG. 5 is a drawing illustrating the interior of a battery cell according to one embodiment of the present invention. FIG. 6 is a drawing for explaining the size of the pressurizing part of a cell case according to one embodiment of the present invention. FIG. 7 is a drawing illustrating a pressurized portion in which an electrolyte is contained in an internal space in a cell case according to another embodiment of the present invention. Specific details for implementing the invention

[0031] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0032] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0033] Furthermore, 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 invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0034] Each component of the present invention is schematically illustrated in the drawings, and the size or thickness of the lines of the components may be expressed somewhat exaggerated for ease of understanding.

[0035] FIG. 1 is a schematic diagram showing the interior of a battery module (1) according to an embodiment of the present invention. FIG. 2 is an assembly diagram of a battery cell (10) according to an embodiment of the present invention. FIG. 3 is a diagram showing a cell case (200) in an unfolded state according to an embodiment of the present invention. FIG. 4 is a diagram showing a part of the AA' cross-section of FIG. 3.

[0036] A battery module (1) according to one embodiment of the present invention may include a housing (20) and a plurality of battery cells (10) as illustrated in FIG. 1. Here, the plurality of battery cells (10) may be arranged adjacent to each other inside the housing (20) and may be electrically connected. At this time, the plurality of battery cells (10) may be connected in various forms and arranged inside the housing (20). For example, the plurality of battery cells (10) may all be connected in series or all be connected in parallel. In addition, the plurality of battery cells (10) may be connected in a mixed form of series and parallel.

[0037] In a battery module (1) according to one embodiment of the present invention, the housing (20) serves to accommodate a plurality of batteries and may have various structures. For example, the housing (20) may have a hollow rectangular box structure in which a space is formed to accommodate a plurality of battery cells (10) inside. In addition, the housing (20) may be composed of various materials. For example, the housing (20) may be composed of a metal material such as an aluminum alloy or a polymer-based material. If the housing (20) is composed of a metal material, an insulating coating layer may be formed on the surface of the housing (20).

[0038] Referring to FIG. 2, a battery cell (10) according to one embodiment of the present invention is a secondary battery capable of charging and discharging, and may include an electrode assembly (100) and a cell case (200) that accommodates the electrode assembly (100). The electrode assembly (100) may be formed by alternately stacking electrodes and separators. Electrodes such as positive and negative electrodes may be manufactured by applying a slurry, which is a mixture of an electrode active material, a binder, and a plasticizer, to a positive current collector and a negative current collector. Separators may be stacked between the electrodes to form an electrode assembly (100), and the electrode assembly (100) may be accommodated in the cell case (200), and after injecting an electrolyte, the cell case (200) may be sealed.

[0039] In addition, in a battery cell (10) according to one embodiment of the present invention, the electrode assembly (100) may include electrode tabs (110). The electrode tabs (110) are respectively connected to the positive and negative electrodes of the electrode assembly (100) and protrude outward from the electrode assembly (100), so as to serve as a path through which electrons can move between the inside and outside of the electrode assembly (100). A plurality of electrode tabs (110) may protrude in different directions from the electrode assembly (100), but are not limited thereto, and a plurality of electrode tabs (110) may protrude in parallel in the same direction or protrude in various directions.

[0040] In addition, in a battery cell (10) according to one embodiment of the present invention, the electrode assembly (100) may include an electrode lead (120) connected to an electrode tab (110) to supply electricity to the outside of the battery cell (10). The electrode lead (120) may be connected to the electrode tab (110) by spot welding or the like. The electrode assembly (100) may include an insulating part (130) surrounding a part of the electrode lead (120). The insulating part (130) may be positioned between the cell case (200) to insulate the electrode lead (120) from the cell case (200).

[0041] A cell case (200) according to one embodiment of the present invention may be manufactured from a highly flexible material to accommodate an electrode assembly (100) inside. By drawing molding a flexible cell case (200) using a punch or the like, a portion of the cell case (200) may be stretched to form an indented cup portion (210) having a pocket-shaped receiving space (220), thereby manufacturing the cell case (200). The cell case (200) may accommodate and seal the electrode assembly (100) such that a portion of the electrode lead (120) is exposed.

[0042] When forming a cup portion (210) in a cell case (200), only one cup portion (210) may be formed in a cell case (200), but is not limited thereto, and two cup portions (210) may be drawn and formed adjacent to each other in a cell case (200). Then, as shown in FIG. 2, two adjacent cup portions (210) may be formed. Each cup portion (210) may have the same depth, but is not limited thereto, and the depths of each cup portion (210) may differ from each other. After housing an electrode assembly (100) in one cup portion (210), the cell case (200) may be folded around an axis so that another cup portion (210) faces the cup portion (210). Accordingly, the other cup portion (210) may accommodate the electrode assembly (100) from the upper side. Since two cup portions (210) accommodate one electrode assembly (100), an electrode assembly (100) with a thicker thickness can be accommodated than when there is only one cup portion (210).

[0043] Additionally, by folding the cell case (200), a folding section connecting two cup sections (210) can be formed. Since the folding section is formed by folding, it is integrally connected, so the number of sides to be sealed can be reduced when performing a sealing process later. Therefore, the process speed can be improved and the number of sealing processes can be reduced. In particular, if the cross-section of the cup section (210) is close to a rectangle, the cell case (200) with the folding section formed can be sealed by sealing three sides. For convenience of explanation, the present disclosure describes the cell case (200) including the folding section. However, the concept of the present invention may also be applied to a cell case (200) that does not include the folding section.

[0044] When an electrode lead (120) is connected to an electrode tab (110) of an electrode assembly (100) and an insulating portion (130) is formed on a part of the electrode lead (120), the electrode assembly (100) is accommodated in a receiving space (220) provided in a cup portion (210), and another cup portion (210) can cover the electrode assembly (100). After that, a part of the side portion (230) extending from the cup portion (210) on the side other than where the folding portion is located is sealed, an electrolyte is injected into the receiving space (220) through the unsealed side portion (230), and after the electrolyte is injected, the unsealed side portion (230) can be sealed.

[0045] Meanwhile, as described above, as charging and discharging progresses, a swelling phenomenon occurs in which the volume of the battery cell (10) expands. And when the battery cell (10) swells due to the swelling phenomenon, an imbalance in surface pressure occurs between the battery cells (10) and the battery cells (10) inside the battery module (1) shown in FIG. 1.

[0046] In particular, this surface pressure imbalance phenomenon may result from the thickness variation occurring in the center region and the edge region (140) of the electrode assembly (100) due to the stacked structure of the electrode assembly (100) and the structure for electrical connection. More specifically, the edge region (140) of the electrode assembly (100) may be an area adjacent to the electrode tab (110). This is because a welding process is performed while pressing the electrode tabs (110) to connect the electrode leads (120) to the electrode tabs (110) connected to the stacked electrodes. Accordingly, a thickness variation may occur in the edge region (140) compared to the center region of the electrode assembly (100), and this may cause a surface pressure imbalance between adjacent battery cells (10) as charging and discharging proceeds.

[0047] Furthermore, the surface pressure imbalance applied to the aforementioned battery cell (10) causes a problem in which the lifespan of the battery cell (10) and the battery module (1) is reduced. Moreover, it may lead to a so-called sudden drop phenomenon, such as a rapid decrease in the capacity of the battery cell (10) or a rapid increase in resistance.

[0048] Accordingly, a cell case (200) according to one embodiment of the present invention may include a pressurizing part (240) provided in a cup part (210), as shown in FIGS. 2 and 3. Here, the pressurizing part (240) may be provided in the cup part (210) so as to face an edge region (140) adjacent to the electrode tab (110) of the received electrode assembly (100) when the electrode assembly (100) is received in the cup part (210). The pressurizing part (240) may be configured to pressurize the edge region (140) of the received electrode assembly (100).

[0049] More specifically, in a cell case (200) according to one embodiment of the present invention, the pressurizing part (240) may be configured to form an internal space (241) as shown in FIG. 4. The pressurizing part (240) may include an inlet (242) configured to allow gas to flow from the receiving space (220) into the internal space (241). Here, the volume of the internal space (241) of the pressurizing part (240) may be varied by the inflow of gas.

[0050] That is, in a cell case (200) according to one embodiment of the present invention, the pressurizing part (240) can be inflated by the inflow of gas. Here, the gas may include gases generated by charging and discharging. In addition, the pressurizing part (240) may be made of a highly flexible material for this purpose. Furthermore, the pressurizing part (240) can be inflated by the inflow of gas and pressurize the edge region (140) of the electrode assembly (100) when the electrode assembly (100) is received in the cup part (210).

[0051] Furthermore, in a cell case (200) according to one embodiment of the present invention, a pressurizing member (240) may protrude from the inner surface of the cup portion (210) with respect to the depth direction of the cup portion (210). Additionally, the pressurizing member (240) may be provided in the cup portion (210) to face at least one of the two sides of the edge region (140) of the received electrode assembly (100). Furthermore, as described above, a pair of cup portions (210) may be formed spaced apart from each other when the cell case (200) is unfolded. At this time, the pressurizing member (240) may be provided in each of the pair of cup portions (210).

[0052] For example, as illustrated in FIG. 3, a pressure member (240) may be provided on each of the pair of cup members (210). In this case, both sides of the edge region (140) of the electrode assembly (100) may face the pressure member (240). As another example, the pressure member (240) may be provided on only one of the pair of cup members (210). In this case, either of the two sides of the edge region (140) of the electrode assembly (100) may face the pressure member (240).

[0053] And through this, when the electrode assembly (100) is received in the cup portion (210), the pressurizing portion (240) pressurizes the edge region (140) of the received electrode assembly (100) to improve the surface pressure imbalance applied to the battery cell (10). Additionally, by improving the surface pressure applied to the battery cell (10), the lifespan of the battery cell (10) and the battery module (1) can be increased, and sudden drop phenomena such as a rapid decrease in the capacity of the battery cell (10) or a rapid increase in resistance can be improved.

[0054] Additionally, in a cell case (200) according to one embodiment of the present invention, the pressurizing portion (240) may include a coupling surface (243), a pressurizing surface (244), and a connecting surface (245). Here, the coupling surface (243) may be coupled to the cup portion (210). The pressurizing surface (244) may face the edge region (140) of the received electrode assembly (100), and as described above, when the pressurizing portion (240) swells, it may pressurize the edge region (140) of the electrode assembly (100).

[0055] Additionally, the connecting surface (245) may be provided with an inlet (242) that connects the coupling surface (243) and the pressurizing surface (244). That is, the inlet (242), which allows gas to flow from the receiving space (220) into the internal space (241), may be provided on the connecting surface (245) that connects the coupling surface (243) and the pressurizing surface (244), rather than on the coupling surface (243) that is coupled to the cup portion (210) or the pressurizing surface (244) that pressurizes the edge area (140) of the electrode assembly (100). As will be described later, by providing the inlet (242) on the connecting surface (245), the flow of gas into the internal space (241) can be facilitated, and damage to the electrode assembly can be minimized when the pressurizing portion (240) is inflated and pressurizes the edge area (140) of the electrode assembly (100) that is received.

[0056] Referring again to FIG. 2 and FIG. 3, a pair of cup portions (210) may be formed spaced apart from each other when the cell case (200) is unfolded. At this time, a pressurizing portion (240) may be provided in each of the pair of cup portions (210). The pressurizing portion (240) may press both sides of the edge region (140) of the received electrode assembly (100). Thus, the surface pressure imbalance applied to the battery cell (10) can be improved more efficiently.

[0057] FIG. 5 is a drawing showing the interior of a battery cell (10) according to one embodiment of the present invention.

[0058] As described above, the pressurizing unit (240) can pressurize the edge region (140) of the received electrode assembly (100) as gas is introduced from the receiving space (220) into the internal space (241) through the inlet (242). At this time, the inlet (242) may include a valve (246) that moves the gas due to the pressure difference between the internal pressure of the receiving space (220) and the internal pressure of the internal space (241).

[0059] Here, the valve (246) may include a valve (246) having a structure that moves gas only in one direction, that is, from the receiving space (220) to the internal space (241). For example, the valve (246) provided in the pressurizing part (240) may be an aroma valve. Through this, the gas generated by charging and discharging is allowed to flow from the receiving space (220) to the internal space (241), causing the pressurizing part (240) to expand and pressurize the edge region (140) of the received electrode assembly (100).

[0060] In addition, in a battery cell (10) according to one embodiment of the present invention, an electrolyte may be received together with the electrode assembly (100) in the receiving space (220) of the electrode assembly (100). Accordingly, the valve (246) described above may be configured to allow gas to pass through while blocking the passage of liquid. For example, the valve (246) provided in the pressurizing part (240) may include a membrane having micropores and made of a hydrophobic material. Accordingly, the electrolyte in the receiving space (220) can be more effectively prevented from flowing into the interior of the pressurizing part (240).

[0061] Additionally, in a cell case (200) according to one embodiment of the present invention, a valve (246) may be provided in a pressurizing part (240) so as to protrude from the end of the electrode assembly (100), as shown in FIG. 5. This is to prevent the electrode assembly (100) from being damaged by the valve (246) when the edge region (140) of the electrode assembly (100) is pressurized through the pressurizing part (240).

[0062] FIG. 6 is a drawing for explaining the size of a pressurizing part (240) of a cell case (200) according to an embodiment of the present invention. The length of the pressurizing part (240) described below may be the length in the vertical direction of FIG. 6, and the width of the pressurizing part (240) may be the length in the horizontal direction of FIG. 6. In addition, the width of the electrode assembly (100) may be the length in the vertical direction of FIG. 6, and the length of the electrode assembly (100) may be the length in the horizontal direction of FIG. 6.

[0063] Referring to FIG. 2 and FIG. 6 together, the electrode tab (110) may be connected to each side of the electrode assembly (100). The pressing portion (240) may be provided in the cup portion (210) so as to face the edge regions (140) located on each side of the received electrode assembly (100). That is, the pressing portion (240) of the cell case (200) according to one embodiment of the present invention may press the edge regions (140) located on each side of the electrode assembly (100). Here, the length (L1) of the pressing portion (240) may correspond to the width (L4) of the received electrode assembly (100). That is, the length (L1) of the pressing portion (240) may be the same length as the width (L4) of the received electrode assembly (100), or may be a similar length. And through this, the surface pressure imbalance applied to the battery cell (10) can be improved more efficiently.

[0064] Additionally, in a cell case (200) according to one embodiment of the present invention, the ratio of the width (L2, L3) of the pressurizing part (240) to the length (L5) of the electrode assembly (100), i.e., (L2+L3) / L5, may be 0.12 or more and 0.16 or less.

[0065] If the ratio of the width (L2, L3) of the pressurizing part (240) to the length (L5) of the electrode assembly (100) is small, the width of the edge region (140) of the electrode assembly (100) being pressed by the pressurizing part (240) is small, so the effect of improving the surface pressure imbalance may be insufficient. And if the ratio of the width (L2, L3) of the pressurizing part (240) to the length (L5) of the electrode assembly (100) is large, interference between adjacent battery cells (10) caused by the pressurizing part (240) may occur, which may instead lead to a problem where the surface pressure imbalance becomes even greater. Accordingly, in the cell case (200) according to one embodiment of the present invention, the ratio of the width (L2, L3) of the pressurizing part (240) to the length (L5) of the electrode assembly (100), (L2+L3) / L5, may preferably be 0.12 or more and 0.16 or less.

[0066] FIG. 7 is a drawing illustrating a pressurized portion (240) in which an electrolyte (247) is contained in an internal space (241) in a cell case (200) according to another embodiment of the present invention.

[0067] Below, details that overlap with the previously explained content will be omitted, and the focus will be on the differences.

[0068] In a cell case (200) according to another embodiment of the present invention, the pressurizing part (240) may further include an electrolyte (247) contained in an internal space (241). Here, the electrolyte (247) may be the same as the electrolyte contained in the receiving space (220) together with the electrode assembly (100) in the battery cell (10) described above.

[0069] More specifically, the electrolyte (247) contained in the internal space (241) of the pressurizing part (240) can be heated and vaporized by the heat generated as charging and discharging proceeds. Accordingly, the pressurizing part (240) can swell and pressurize the edge region (140) of the contained electrode assembly (100).

[0070] At this time, the inlet port (242) may include a valve (246) having a structure that moves gas only in one direction, that is, from the receiving space (220) to the internal space (241), as described above, so that the edge region (140) of the received electrode assembly (100) can be pressurized more efficiently. In addition, the valve (246) described above may be configured to allow gas to pass through but block the passage of liquid, so that the electrolyte in the receiving space (220) can be prevented from flowing into the internal space (241) of the pressurizing part (240), or the electrolyte (247) in the internal space (241) can be prevented from flowing out.

[0071] Additionally, in a cell case (200) according to another embodiment of the present invention, the amount of electrolyte (247) contained in the internal space (241) of the pressurizing part (240) is not particularly limited. This is because, as described above, the contained electrolyte (247) can be heated and vaporized by the heat generated as charging and discharging proceeds, and gas can be introduced into the internal space (241) of the pressurizing part (240) through the inlet (242). Therefore, even if the electrolyte (247) contained in the internal space (241) is completely vaporized in the internal space (241), the pressurizing part (240) can still be pressurized by the gas introduced into the internal space (241), thus allowing the edge region (140) of the contained electrode assembly (100) to be pressurized.

[0072] Additionally, the electrolyte (247) contained in the internal space (241) of the pressurizing part (240) in the cell case (200) according to another embodiment of the present invention may be the same as the electrolyte contained together with the electrode assembly (100) in the battery cell (10) described above. Accordingly, even if the pressure inside the battery cell (10) increases as charging and discharging proceeds and the pressurizing part (240) ruptures, causing the electrolyte (247) to leak out of the pressurizing part (240), the performance of the battery cell (10) can be maintained without issue. Furthermore, even if the pressurizing part (240) ruptures, the electrolyte (247) can be replenished into the receiving space (220), thus providing an additional effect of maintaining the performance of the battery cell (10).

[0073] To summarize the above, the present invention can improve the imbalance of surface pressure applied to the battery cell (10) by providing a pressure part (240) for applying pressure to the edge region (140) of the electrode assembly (100) in the cup part (210) of the cell case (200). Additionally, as charging and discharging proceed, gas is introduced into the internal space (241) of the pressure part (240), causing the pressure part (240) to expand, thereby improving the imbalance of surface pressure applied to the battery cell (10) more efficiently. Furthermore, by improving the surface pressure applied to the battery cell (10), the lifespan of the battery cell (10) and the battery module (1) can be increased, and sudden drop phenomena, such as a rapid decrease in the capacity of the battery cell (10) or a rapid increase in resistance, can be improved.

[0074] The above description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention.

[0075] Accordingly, the embodiments disclosed in this invention are intended to explain, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments.

[0076] The scope of protection of the present invention shall be interpreted by the claims below, and all technical ideas within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention. Explanation of the symbols

[0077] 1: Battery module 10: Battery cell 20: Housing 100: Electrode assembly 110: Electrode tab 120: Electrode lead 130: Insulation part 140: Edge area 200: Cell Case 210: Cup 220: Capacity 230: Side 240: Pressurizing part 241: Interior space 242: Inlet 243: Joining surface 244: Pressurized surface 245: Connection surface 246: Valve 247: Electrolyte L1: Length of the pressurized section L2, L3: Width of the pressurized section L4: Width of electrode assembly L5: Length of electrode assembly

Claims

Claim 1 A cell case for accommodating an electrode assembly connected to an electrode tab, comprising: a cup portion recessed to form a receiving space in which the electrode assembly is accommodated; and a pressurizing portion provided in the cup portion to face an edge region adjacent to the electrode tab of the accommodated electrode assembly, configured to pressurize the edge region, wherein the pressurizing portion is configured to form an internal space and includes an inlet configured to allow gas to flow from the receiving space into the internal space. Claim 2 In claim 1, the pressurizing part is a cell case in which the volume of the internal space is varied by the inflow of gas. Claim 3 In claim 1, the pressurizing part is a cell case protruding from the inner surface of the cup part with respect to the depth direction of the cup part. Claim 4 In claim 1, the pressurizing part is a cell case facing at least one of the two sides of the edge region of the received electrode assembly. Claim 5 In claim 1, the cell case comprises: a coupling surface coupled to the cup portion; a pressure surface facing the edge region of the received electrode assembly; and a connecting surface connecting the coupling surface and the pressure surface, wherein the inlet is provided. Claim 6 In claim 1, the cell case comprising a valve that moves gas by the pressure difference between the internal pressure of the receiving space and the internal pressure of the internal space. Claim 7 In paragraph 6, the valve is a cell case configured to allow gas to pass through and block the passage of liquid. Claim 8 In paragraph 6, the valve is a cell case protruding from the end of the electrode assembly. Claim 9 In claim 1, the pressurizing part further comprises a cell case containing an electrolyte contained in the internal space. Claim 10 In claim 1, the electrode tab is connected to each side of the electrode assembly, and the pressure member is provided in the cup portion to face the edge region located on each side of the received electrode assembly. Claim 11 In item 10, the length of the above-mentioned pressurizing part is a cell case corresponding to the width of the above-mentioned electrode assembly. Claim 12 A cell case according to claim 10, wherein the ratio of the width of the pressurizing part to the length of the received electrode assembly is 0.12 or more and 0.16 or less. Claim 13 In claim 1, the cup portions are spaced apart from each other and formed as a pair when the cell case is unfolded, and the pressurizing portions are cell cases provided in each of the pair of cup portions. Claim 14 A battery cell comprising: an electrode assembly connected to an electrode tab; and a cell case accommodating the electrode assembly and an electrolyte, wherein the cell case comprises: a cup portion recessed to form a receiving space in which the electrode assembly is accommodated; and a pressurizing portion provided in the cup portion to face an edge region adjacent to the electrode tab of the accommodated electrode assembly, configured to pressurize the edge region, wherein the pressurizing portion comprises an inlet configured to form an internal space and configured to allow gas to flow from the receiving space into the internal space. Claim 15 A battery module comprising: a housing; and a plurality of battery cells arranged adjacently to each other within the housing and electrically connected, wherein at least one of the plurality of battery cells is an electrode assembly connected to an electrode tab; and a cell case that accommodates the electrode assembly and an electrolyte, wherein the cell case comprises: a cup portion recessed to form a receiving space in which the electrode assembly is accommodated; and a pressurizing portion provided in the cup portion to face an edge region adjacent to the electrode tab of the accommodated electrode assembly, configured to pressurize the edge region, wherein the pressurizing portion is configured to form an internal space and includes an inlet configured to allow gas to flow from the receiving space into the internal space.

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