Battery module, battery pack and device including the battery module

Abstract

The present invention relates to a battery module including an expansion mitigation unit, and more particularly, to a battery module including a cell stack having one or more battery cells stacked therein and a module housing for accommodating the cell stack therein, and the battery module has an expansion mitigation unit having a protrusion capable of applying pressure to at least a portion of an outermost battery cell arranged on an outermost portion of the cell stack.

Description

Technical Field

[0001] This application claims the benefit of priority to Korean Patent Application No. 2021-0003604, filed on January 11, 2021, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to a battery module including a swelling mitigation unit. More specifically, the present invention relates to a battery module including a swelling mitigation unit capable of applying pressure to a battery cell, wherein the swelling mitigation unit is disposed at and / or in a housing of a module housing to mitigate the behavior of lithium plating, thereby preventing the life of the battery cell from being shortened. Background Art

[0003] As the demand for mobile devices such as smartphones increases, the demand for secondary batteries used as their energy sources also increases. In addition, secondary batteries are used in electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (P-HEV), energy storage systems (ESS), etc.

[0004] The demand for lithium secondary batteries, one of the secondary batteries, is unstoppably high. Lithium secondary batteries operate because lithium ions are repeatedly inserted into and deintercalated from the negative electrode and the positive electrode. In an electrolyte containing lithium salts, lithium ions can move between electrodes, but electrons cannot move between electrodes.

[0005] Lithium precipitation (i.e., so-called Li-plating) causes side reactions with the electrolyte and changes the kinetic balance of the secondary battery. As a result, the capacity and cycle life of the battery are reduced, and safety-related problems such as loss of overcharge control function arise. During repeated charging and discharging, lithium metal is dendritically precipitated on the surface of one electrode, thereby seriously threatening the safety of the battery. In the case where the dendritically precipitated metallic lithium penetrates the separator and contacts the other electrode, an internal short circuit occurs, and due to the rapid chemical reaction, the temperature of the battery is increased. As a result, the battery cell or module may catch fire, which may cause dangerous consequences such as explosion. Lithium plating occurs more frequently around the position where the electrode tab of the battery cell protrudes from it, and as the number of times and cycles of charging and discharging increase, the battery cell swells at the position where the electrode tab of the battery cell protrudes from it. This phenomenon occurs more significantly in a battery module including a plurality of stacked battery cells than in a unit battery cell. The cycle life of the battery cells constituting the battery module may be shorter than that of the unit battery cell, and the scale of the accident may increase due to the plurality of battery cells.

[0006] Figures 1 to 3 A conventional battery module 100 is shown. Figures 1 to 3, the battery module 100 is configured so that a cell stack 200 consisting of a plurality of stacked battery cells 21, 22, ..., n-1 and n is accommodated in a module housing (not shown in the figure). The wide outer surfaces of the two battery cells 21 and n disposed on the outermost sides of the cell stack 200 may face the first side cover 130 and the second side cover 140 of the module housing, respectively, the expansion control pad 180 may be located between each of the outermost battery cells and a corresponding one of the side covers of the module housing, and the resin layer 400 configured to fix the cell stack 200 may be inserted between the cell stack 200 and the lower cover 120. In order to ensure the stability of the battery cells 21, 22, ..., n-1 and n constituting the cell stack 200, an adhesive 300 may be inserted between the facing battery cells at a predetermined area.

[0007] The battery cells 21, 22, ..., n-1, and n in the conventional battery module 100 repeatedly expand and contract during charging and discharging, and the electrode active material may be separated or degraded due to such deformation of the battery cells, and a side reaction may occur, whereby the battery performance may be degraded. In order to solve the above-mentioned problems, an expansion control pad 180 is generally provided between the module housing and each of the outermost battery cells or between the battery cells, wherein when the battery cell expands, the expansion mitigation pad is compressed to perform a buffering operation, thereby controlling the expansion of the battery cell.

[0008] like Figure 3 As shown in , when the battery cell expands, the volume increment of the middle portion of the battery cell and the volume increment of the edge of the battery cell are different from each other. That is, when the volume of the battery cell expands, the middle portion of the battery cell expands into a pot shape compared to the edge of the battery cell. If the entire surface of the expanded battery cell is uniformly supported, the battery cell is deformed by the gas generated in the battery cell and the lithium plating caused thereby.

[0009] Figure 4 2 is a schematic diagram illustrating battery cells before and after deformation using, for example, one outermost battery cell 21 among conventional battery cells 21, 22, ..., n-1, and n. Such expansion may occur in all battery cells including the outermost battery cell. Figure 4 , the portion of the battery cell 21 adjacent to the electrode tab and the electrode lead 2 expands relatively significantly. Since the expansion of the middle portion is suppressed, the left and right portions of the battery cell where the electrode tab is located expand due to the gas generated in the battery cell. As charging and discharging are continuously performed, the battery cell is more significantly deformed. Each battery cell expands, and the cell stack 200 in which a plurality of battery cells are connected to each other is more significantly deformed, which shortens the life of the battery module 100 and also causes accidents such as fire.

[0010] In order to extend the life of the battery cells 21, 22, ..., n-1, and n in the battery module 100 and improve the stability of the battery module, it is necessary to mitigate the expansion of the battery cells in the battery module 100 due to lithium plating. However, there are limitations in suppressing the lithium plating phenomenon due to the electrochemical mechanism of the battery cells.

[0011] Patent document 1 discloses a lithium secondary battery, which is configured so that microcapsules are formed between a negative electrode and a separator, the microcapsules include a stabilizing material configured to stabilize lithium precipitated from the negative electrode when the secondary battery is overcharged, and the surface of the microcapsule is formed as a thermoplastic resin layer, which is configured to collapse when the secondary battery is overcharged so as to discharge the stabilizing material.

[0012] Patent document 2 discloses a lithium precipitation detection method, which observes the voltage change of a secondary battery based on the SOC during battery charging to detect lithium precipitation from the negative electrode in real time, characterized in that the point where the battery voltage rise rate slows down is determined as the point where lithium precipitation occurs.

[0013] Patent Documents 1 and 2 disclose technologies for ensuring safety of lithium secondary batteries against lithium precipitation, but do not disclose a battery module including a swelling mitigation unit capable of mitigating swelling of battery cells provided in the battery module that occurs during charge and discharge of the battery module.

[0014] In a battery module including a cell stack composed of a plurality of stacked battery cells, no effective means capable of solving the problems caused by deformation of the battery cells has been proposed.

[0015] (Patent Document 1) Korean Patent Application Publication No. 2017-0111566

[0016] (Patent Document 2) Korean Patent Application Publication No. 2017-0023583 Summary of the invention

[0017] Technical issues

[0018] The present invention has been made in view of the above problems, and an object of the present invention is to provide a battery module including a swelling mitigation unit capable of preventing shortening of the life of battery cells in the battery module while using conventional battery modules and battery cells without change.

[0019] Another object of the present invention is to provide a battery module including a swelling mitigation unit capable of quickly moving gas generated during use of the battery module to the periphery of a battery cell instead of staying in an electrode assembly of the battery cell.

[0020] Technical Solution

[0021] In order to achieve the above objectives, a battery module according to the present invention includes: a cell stack, which is composed of one or more stacked battery cells; and a module shell, which is configured to accommodate the cell stack therein, wherein an expansion reduction unit is arranged to face the outermost battery cell arranged at the outermost side of the cell stack, and the expansion reduction unit has a protrusion configured to apply pressure to at least a portion of the battery cell.

[0022] The expansion mitigation unit may be located between an outermost battery cell disposed at an outermost side of the cell stack and the module case.

[0023] The swelling mitigation unit may be disposed to face two outermost battery cells disposed at outermost sides of the cell stack.

[0024] The convex portion of the swelling mitigation unit may be located only at a predetermined region of a middle portion of the outermost battery cell.

[0025] The convex portion of the expansion mitigation unit may be made of an elastic material.

[0026] The convex portion of the swelling mitigation unit may be deformed into a concave shape when a predetermined pressure or more is applied thereto.

[0027] An adhesive may be interposed between the facing surfaces of the battery cells.

[0028] The adhesive may be applied to the entire facing surface of the battery cell.

[0029] The expansion mitigation unit may be integrally formed at the side cover of the module housing.

[0030] In addition, the present invention provides a battery pack including the battery module and a device including the battery pack.

[0031] In the present invention, one or more configurations that do not conflict with each other may be selected and combined from among the above configurations.

[0032] Beneficial Effects

[0033] In the battery module according to the present invention, in order to suppress abnormal expansion of the battery cells and the battery module according to the number of times of charging and discharging, an expansion reduction unit is provided at each outermost battery cell, thereby preventing the life of the battery cell from being shortened and improving the stability of the battery cell.

[0034] The convex portion of the expansion mitigation unit is deformed into a concave shape when a predetermined pressure or higher is applied thereto, thereby reducing the pressure applied to the central portion of the battery cell and the battery module. As a result, the outer periphery of the electrode joint does not expand, thereby reducing the occurrence of lithium plating, and thus, preventing the internal temperature of the battery cell from increasing and accidents related to the battery module such as fire depending thereon.

[0035] Since the swelling mitigation unit according to the present invention is easily provided in a conventional battery module without modification, it is unnecessary to change the battery module manufacturing process, which is economically advantageous.

[0036] Since the adhesive layer is applied to the entirety of each of the facing surfaces of adjacent battery cells in the battery module, gas generated in the battery cells during charge and discharge can move to the outer periphery of the battery cells, thereby preventing uneven degradation of the battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram of a conventional battery module.

[0038] Figure 2 It is along Figure 1 A cross-sectional view taken along line AA'.

[0039] Figure 3 yes Figure 1 An exploded perspective view of a battery module is shown in FIG.

[0040] Figure 4 is a schematic diagram illustrating a conventional battery cell before and after its deformation.

[0041] Figure 5 is an exploded perspective view of a battery module according to a first embodiment of the present invention.

[0042] Figure 6 It is along Figure 5 A cross-sectional view taken along line AA'.

[0043] Figure 7 is an exploded perspective view of a battery module according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0044] In the present application, it should be understood that the terms "include", "have", "comprises", etc. indicate the existence of the described features, numbers, steps, operations, elements, components or a combination thereof, but do not exclude the existence or addition of one or more other features, numbers, steps, operations, elements, components or a combination thereof.

[0045] In addition, the same reference numerals will be used throughout the drawings to represent components that perform similar functions or operations. Where a component is referred to as being connected to another component in the specification, not only may this component be directly connected to another component, but this component may also be indirectly connected to another component via other components. In addition, unless otherwise specified, including a specific element does not mean that other elements are not included, but rather means that these elements may be further included.

[0046] Hereinafter, a battery module according to the present invention will be described with reference to the accompanying drawings.

[0047] Figure 5 is an exploded perspective view of a battery module according to a first embodiment of the present invention, and Figure 6 It is along Figure 5 A cross-sectional view taken along line AA'.

[0048] Reference Figure 5 and Figure 6 , a battery module 1000 according to the first embodiment of the present invention may include a cell stack 1200 consisting of a plurality of stacked battery cells (reference numerals not shown) and an expansion mitigation unit 1500 disposed in a module housing (reference numerals not shown) having a substantially hexahedral shape.

[0049] The module housing may include an upper cover 1110, a lower cover 1120, a first side cover 1130 and a second side cover 1140 facing each other so as to be positioned toward a side surface (i.e., a wide surface) of the cell stack 1200, and a front cover 1150 and a rear cover 1160 at the surface of the cell stack where the electrode terminals are provided.

[0050] Here, the front cover 1150 and the rear cover 1160 are arranged to face the direction in which the electrode leads of the battery cells are positioned so as to protect the electrode leads and the bus bars 1170, and a pair of side covers 1130 and 1140 protect the side surfaces (XZ plane) of the cell stack 1200 housed in the module housing.

[0051] The upper cover 1110 and the lower cover 1120 protect the upper portion and the lower portion of the cell stack 1200 , respectively.

[0052] The upper cover 1110, the lower cover 1120, the pair of side covers 1130 and 1140, the front cover 1150, and the rear cover 1160 may be independently manufactured and then assembled with each other. Alternatively, some of the covers may be integrally formed as desired.

[0053] The battery cells having the above configuration are disposed in close contact with each other in the module case in a state in which the side surfaces (XZ plane) of the battery cells stand parallel to the first and second side covers 1130 and 1140 of the module case.

[0054] The cell stack 1200 accommodated in the internal space of the module housing is configured such that a plurality of battery cells are stacked with wide surfaces of the battery cells in close contact with each other, and each of the battery cells includes a cell housing (not shown) configured to accommodate an electrode assembly (not shown) and an electrode lead (not shown).

[0055] The cell case is a bag-shaped cell case (made of a laminated sheet), wherein at least one electrode assembly is accommodated in a accommodating portion, and the edge of the accommodating portion is melted, whereby the accommodating portion is hermetically sealed, and a pair of electrode leads are connected to opposite sides or one side of the electrode assembly so as to protrude outward from the cell case. Of course, the positive electrode connector and the negative electrode connector of the electrode assembly may be electrically connected to each other, respectively, and may be exposed outward from the cell case, or the electrode lead may be directly connected to the electrode assembly without a connector.

[0056] The electrode assembly may be a jelly roll type battery assembly, a stacked type electrode assembly, a stacked and folded type electrode assembly, or a laminated and stacked type electrode assembly, the jelly roll type battery assembly being configured to have a structure in which a long sheet type positive electrode and a long sheet type negative electrode are wound so that a separator is interposed therebetween, the stacked type electrode assembly being configured to have a structure in which a rectangular positive electrode and a rectangular negative electrode are stacked so that a separator is interposed therebetween, the stacked and folded type electrode assembly being configured to have a structure in which a unit cell is wound using a long separation film, the laminated and stacked type electrode assembly being configured to have a structure in which battery cells are stacked so that a separator is interposed therebetween and then attached to each other. However, the present invention is not limited thereto.

[0057] Obviously, in addition to the commonly used liquid electrolyte, the electrolyte in the battery cell can also be replaced by a solid electrolyte or a gel-type quasi-solid electrolyte obtained by adding additives to the solid electrolyte. The gel-type quasi-solid electrolyte has an intermediate phase between liquid and solid.

[0058] The electrode assembly is housed in a cell shell, and the cell shell is generally configured to have a laminate structure including an inner layer, a metal layer, and an outer layer. The inner layer is arranged to be in direct contact with the battery assembly, so the inner layer must exhibit high insulation properties and high resistance to electrolyte solutions. In addition, the inner layer must exhibit high sealing properties so that the cell shell is hermetically sealed relative to the outside, that is, the thermal bonding sealing portion between the inner layers must exhibit excellent thermal bonding strength. The inner layer can be made of a material selected from polyolefin resins, polyurethane resins, and polyimide resins such as polypropylene, polyethylene, polyvinyl acetate, or polybutylene that exhibit excellent chemical resistance and high sealing properties. However, the present invention is not limited thereto, and it is most preferred to use polypropylene that exhibits excellent mechanical and physical properties such as tensile strength, stiffness, surface hardness, and impact strength and excellent chemical resistance.

[0059] The metal layer disposed adjacent to the inner layer corresponds to a barrier layer configured to prevent moisture or various gases from penetrating into the battery from the outside. As a preferred material for the metal layer, a lightweight and easily formable aluminum thin film can be used.

[0060] The outer layer is disposed on the other surface of the metal layer. The outer layer may be made of a heat-resistant polymer that exhibits excellent tensile strength, moisture permeability resistance, and air permeability resistance so that the outer layer exhibits high heat resistance and chemical resistance while protecting the electrode assembly. As an example, the outer layer may be made of nylon or polyethylene terephthalate. However, the present invention is not limited thereto.

[0061] The expansion mitigation unit 1500 according to the first embodiment of the present invention may be located between the pair of side covers 1130 and 1140 of the module case and the cell stack 1200 .

[0062] The expansion mitigation unit 1500 may include a substantially flat flat portion 1520 and a convex portion 1510 formed to protrude toward the cell stack 1200 based on a wide surface (XZ plane) of the flat portion 1520. Specifically, the convex portion 1510 may be located at a middle portion of the flat portion 1520 in the longitudinal direction (X-axis direction), and the convex portion 1510 may be positioned to be in close contact with a middle portion of an outermost surface (X-axis direction in the XZ plane) of a battery cell located at the outermost side of the cell stack 1200. In addition, the portion of the convex portion 1510 that is disposed to be in close contact with the outermost surface of the outermost battery cell of the cell stack 1200 may be flat or arc-shaped.

[0063] In the initial stage of charging and discharging, the middle part of the battery cell expands. Therefore, as described above, the convex portion 1510 of the expansion mitigation unit 1500 can be set to be in close contact with a predetermined area of ​​the middle part of the battery cell so that the expansion is reduced by its deformation when a predetermined pressure is applied thereto, which is conducive to extending the life. In the present invention, the convex portion 1510 of the expansion mitigation unit 1500 is positioned to be in close contact with the outermost battery cell of the battery cell stack 1200 or adjacent to the outermost battery cell of the battery cell stack 1200 so as to face the outermost battery cell of the battery cell stack. When the battery cell expands during the battery cell charging and the pressure in the battery cell reaches a predetermined pressure or higher, the convex surface of the convex portion 1510 is deformed in a direction toward each of the side covers 1130 and 1140 of the module housing. During the discharge of the battery cell, the battery cell shrinks, and the deformed convex portion 1510 returns to the outermost battery cell corresponding thereto. At this time, the flat portion 1520 is not deformed, that is, the initial shape of the flat portion is maintained.

[0064] When the battery cell expands by a predetermined volume or more during the charging and discharging of the battery cell, whereby the pressure applied to the convex portion 1510 is equal to or higher than the predetermined pressure, the convex portion 1510 is generally deformed into a concave shape. The convex surface of the convex portion 1510 is generally permanently deformed in a direction toward each of the side covers 1130 and 1140 of the module housing, whereby the convex portion 1510 has a concave shape. As a result, no pressure is applied to the battery cell that has expanded to a predetermined or greater level. The convex portion 1510 is deformed so as to be closer to each of the side covers 1130 and 1140 of the module housing than the flat portion 1520. In the present invention, the expansion mitigation unit 1500 that is deformed during the charging and discharging of the battery cell can be used to adjust the degree of pressure applied to the battery cell during the charging and discharging of the battery cell. The battery cell naturally expands due to its charging and discharging, and thus can provide the pressure most suitable for improving the safety and life of the battery cell.

[0065] In the present invention, the expansion mitigation unit 1500 may be made of an elastic material so as to suppress the expansion of the battery cell in the initial stage. When the battery cell expands, the expansion pressure of the battery cell is applied to the convex portion 1510 of the expansion mitigation unit 1500 positioned in close contact with the battery cell. The convex portion 1510 protruding toward the side surface of the battery cell may be deformed due to the expansion of the battery cell. If the convex portion 1510 is made of a non-elastic material, the convex portion may be broken due to the expansion pressure of the battery cell, whereby the battery cell may be damaged, which may cause accidents such as fire. Therefore, when the expansion mitigation unit 1500 is made of an elastic material, the expansion mitigation unit is easily deformed when the battery cell expands, which is conducive to preventing accidents. In addition, no matter how the battery cell is deformed due to its expansion and / or contraction, the flat portion 1520 of the expansion mitigation unit 1500 remains flat, which is conducive to reducing the deformation of the battery cell caused by lithium plating due to the gas generated in the battery cell moving to the opposite end of the battery cell.

[0066] The convex portion 1510 may be brought into close contact with the entire or a portion of the battery cell in the height direction (Z-axis direction). Specifically, the convex portion may be symmetrically arranged from the center of the battery cell to the opposite sides in the height direction. As a result, the convex portion 1510 is brought into close contact with the outside of the battery cell housing from the center of the battery cell to the opposite ends of the battery cell in the height direction where expansion is relatively easy, which helps to reduce expansion.

[0067] Here, the expansion mitigation unit 1500 may be made of an elastic metal or a synthetic resin. Specifically, the expansion mitigation unit may be made of a soft elastic material such as polyurethane (PU) or ethylene propylene diene monomer (EPDM). Since the above elastic materials have excellent vibration absorption and compression rejection, the battery module 1000 may have excellent dimensional stability even if multiple battery cells expand. In the present invention, the material used for the expansion mitigation unit is not limited to the above materials, as long as the expansion mitigation unit can suppress the expansion of the battery cell and deform after the shape of the expansion mitigation unit is maintained until the pressure in the battery cell reaches a predetermined pressure.

[0068] Although in Figure 5 Although not shown, the expansion mitigation unit 1500 according to the first embodiment of the present invention may be configured such that the convex portion 1510 is formed at the middle portion of the flat portion 1520, and one or more convex portions 1510 may be formed. However, the number of convex portions 1510 is not particularly limited as long as the expansion of the battery cell due to lithium plating can be mitigated.

[0069] In addition, if Figure 6 As shown in , an adhesive 1300 may be applied between side surfaces (XZ plane) of adjacent battery cells to bond the battery cells to each other. Preferably, the adhesive 1300 is applied to the entire side surfaces of the adjacent battery cells.

[0070] The adhesive 1300 may be applied to all side surfaces of the battery cells 121, 122, ... and m that are arranged in close contact with each other to constitute the battery cell stack 1200, whereby the adjacent battery cells may be stably coupled to each other in close contact with each other, and thus the battery cell stack 1200 may have a more stable structure. Therefore, the battery cell stack 1200 may be stably accommodated in the module housing without providing the resin layer 400 used in the conventional battery module on the lower cover 1120.

[0071] A resin layer configured to fix the stacked battery cells to the lower surface of the module case in a conventional battery module is not used, which facilitates the gas generated in each battery cell to move toward all peripheries of the battery cell. As a result, the gas generated in the battery cell can be diffused quickly and efficiently, whereby the gas does not stay in the electrode assembly, which facilitates mitigation of expansion of the battery cell and prevention of shortening of the life.

[0072] The adhesive 1300 may be made of polyolefin such as polyethylene (PE), cast polypropylene (cPP), or polypropylene (PP), or a copolymer thereof.

[0073] Figure 7is an exploded perspective view of a battery module 2000 according to a second embodiment of the present invention.

[0074] The second embodiment is the same as the first embodiment except that the expansion mitigation unit 2500 is integrally formed at each of the pair of side covers 2130 and 2140 of the module case. Therefore, only the expansion mitigation unit 2500 will be described hereinafter.

[0075] In the second embodiment of the present invention, the expansion mitigation unit 2500 may be formed at a middle portion of each of the first side cover 2130 and the second side cover 2140 of the module case in the longitudinal direction (X-axis direction). Here, each side cover may constitute a flat portion of the expansion mitigation unit 2500, and a portion of the side cover may be bent so as to protrude toward the cell stack 2200.

[0076] Figure 7 The expansion mitigation unit 2500 is shown to be located at the middle portion of each of the side covers 2130 and 2140 of the module housing in the height direction (Z-axis direction). However, the present invention is not limited thereto, as long as the expansion mitigation unit is disposed above the entire side cover in the height direction (Z-axis direction) and the side covers 2130 and 2140, the upper cover 2110, and the lower cover 2120 are coupled to each other to constitute the module housing. In addition, as Figure 7 As shown in , the expansion mitigation unit 2500 may be a quadrilateral. Alternatively, the expansion mitigation unit may be a polygon, a circle, or an ellipse. However, the shape of the expansion mitigation unit is not particularly limited as long as the expansion mitigation unit can be elastically deformed due to the expansion of the battery cell.

[0077] The battery module according to the present invention described above is suitable for various devices or vehicles such as electric vehicles or hybrid vehicles.

[0078] Although the specific details of the present invention have been described in detail, it will be understood by those skilled in the art that the detailed description thereof only discloses the preferred embodiments of the present invention and therefore does not limit the scope of the present invention. Therefore, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope and technical ideas of the present invention, and it is obvious that such changes and modifications fall within the scope of the appended claims.

[0079] (Description of Reference Symbols)

[0080] 1: Side surface of battery cell

[0081] 2: Electrode leads

[0082] 21, 22, 121, 122, m, n-1, n: battery cells

[0083] 100: Conventional battery module

[0084] 110, 1110, 2110: Top cover

[0085] 120, 1120, 2120: bottom cover

[0086] 130, 1130, 2130: First side cover

[0087] 140, 1140, 2140: Second side cover

[0088] 150, 1150, 2150: Front cover

[0089] 160, 1160, 2160: rear cover

[0090] 170, 1170, 2170: Busbar

[0091] 180:Expansion Control Pad

[0092] 200, 1200, 2200: Cell stacking

[0093] 300, 1300: Adhesive

[0094] 400: Resin layer

[0095] 1500, 2500, 3500: Expansion reduction unit

[0096] 1510, 2510: convex part

[0097] 1520, 2520: Flat part

[0098] 1000: Battery module according to the first embodiment of the present invention

[0099] 2000: Battery module according to the second embodiment of the present invention

[0100] Industrial Applicability

[0101] The present invention relates to a battery module comprising a cell stack consisting of one or more stacked battery cells and a module housing configured to accommodate the cell stack therein, wherein an expansion mitigation unit is arranged to face an outermost battery cell arranged at the outermost side of the cell stack, and the expansion mitigation unit has a protrusion configured to apply pressure to at least a portion of the battery cell, and therefore the present invention has industrial applicability.

Claims

1. A battery module, comprising: A cell stack, the cell stack consisting of one or more stacked battery cells; as well as a module housing configured to accommodate the battery cell stack therein, wherein an expansion mitigation unit is disposed between the outermost battery cell disposed at the outermost side of the battery cell stack and the module housing, the expansion mitigation unit having a flat portion and a convex portion configured to pressurize at least part of the battery cell, wherein the convex portion of the expansion mitigation unit is deformed into a concave shape when a predetermined pressure or higher pressure is applied thereto, Wherein, regardless of how the battery cell is deformed due to its expansion and / or contraction, the flat portion of the expansion mitigation unit remains flat, thereby mitigating deformation of the battery cell caused by lithium plating due to gas generated in the battery cell moving to opposite ends of the battery cell.

2. The battery module according to claim 1, wherein: The swelling mitigation unit is disposed to face the outermost battery cell disposed at the outermost side of the cell stack.

3. The battery module according to claim 2, wherein: The swelling mitigation unit is disposed to face two outermost battery cells disposed at the outermost sides of the cell stack.

4. The battery module according to claim 1, wherein: The convex portion of the swelling mitigation unit is located only at a predetermined area of ​​a middle portion of the outermost battery cell.

5. The battery module according to claim 1, wherein: The convex portion of the expansion mitigation unit is made of an elastic material.

6. The battery module according to claim 1, wherein: An adhesive is interposed between the facing surfaces of the battery cells.

7. The battery module according to claim 6, wherein: The adhesive is applied to the entire facing surfaces of the battery cell.

8. The battery module according to claim 1, wherein: The expansion mitigation unit is integrally formed at a side cover of the module housing. 9 . A battery pack comprising the battery module according to claim 1 .

10. A device comprising the battery pack according to claim 9.

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