Battery cells, battery packs, and automobiles including the same

Abstract

A battery cell according to one embodiment of the present invention includes an electrode assembly including a first electrode, a second electrode, and a separator interposed therebetween, and a battery housing that receives the electrode assembly via an opening formed on one side, and at least a portion of an inner surface of the battery housing is coated with a heat-resistant coating.

Description

[Technical Field]

[0001] The present invention relates to a battery cell, a battery pack, and a vehicle including the same.

[0002] This application claims priority based on Korean Patent Application No. 10-2023-0081280 filed on June 23, 2023, and Korean Patent Application No. 10-2024-0075265 filed on June 10, 2024, the entire contents of which are incorporated herein by reference in their entirety in their specifications and drawings. [Background technology]

[0003] Secondary batteries, which are easily applicable to a range of products and have electrical properties such as high energy density, are commonly used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs), which are powered by electrical sources. These secondary batteries are not only advantageous in that they can dramatically reduce the use of fossil fuels, but also have the advantage of not producing any by-products from energy use, making them environmentally friendly, and are attracting attention as a new energy source for improving energy efficiency.

[0004] 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 multiple battery cells in series. Alternatively, a battery pack may be configured by connecting multiple 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 and / or charge / discharge capacity.

[0005] However, in the case of a conventional battery cell structure, when a thermal event such as a fire and / or explosion occurs, flames may erupt from the sidewall of the battery can rather than from the vent. Therefore, a design that improves the safety of the battery cell is required to prevent such side rupture and prevent the flame from spreading to surrounding battery cells, causing a chain reaction of fire and / or explosion. Summary of the Invention [Problem to be solved by the invention]

[0006] One object of the present invention is to prevent damage to the side of the battery housing in the event of a fire and / or explosion inside the battery cell.

[0007] More specifically, the present invention aims to prevent failure of the beading of the battery housing in the event of a fire and / or explosion inside the battery cell.

[0008] Another object of the present invention is to prevent damage to the side surface of the battery housing, thereby preventing the spread of fire to surrounding battery cells.

[0009] In another aspect, the present invention aims to prevent chain fires by preventing the flame from spreading to surrounding battery cells.

[0010] However, the technical problems that the present invention aims to solve are not limited to the above problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention provided below. [Means for solving the problem]

[0011] To solve the above problems, a battery cell according to one embodiment of the present invention includes an electrode assembly including a first electrode, a second electrode, and a separator interposed therebetween, and a battery housing that receives the electrode assembly through an opening formed on one side, wherein at least a portion of an inner surface of the battery housing is coated with a heat-resistant coating.

[0012] In one aspect of the present invention, the battery housing may include a beading portion in which at least a portion of a side surface is recessed inward.

[0013] Preferably, the heat-resistant coating can cover at least a portion of the beading portion.

[0014] In another aspect of the present invention, the beading portion may include an upper surface positioned above the innermost point of the indentation, and a lower surface positioned below the innermost point of the indentation.

[0015] Preferably, the heat-resistant coating covers the lower surface of the beading portion.

[0016] In yet another embodiment of the present invention, the cover region of the heat-resistant coating has a width in the winding axis direction that is 24% or more of the total height of the battery housing before deformation.

[0017] In one aspect of the present invention, the heat-resistant coating may cover at least a portion of an area extending from an innermost point recessed inwardly of the beading portion in a direction opposite to the opening portion.

[0018] In another aspect of the present invention, the heat-resistant coating may cover at least a portion of an area extending from a point where a flat section of an upper surface of the beading portion starts in a direction opposite to the open portion.

[0019] In one embodiment of the present invention, the heat resistant coating may include at least one of PI, PAI, silicone, and epoxide.

[0020] For example, the thermally resistant coating may include ceramic particles.

[0021] In another aspect of the present invention, the heat resistant coating can include at least one of TiO2 and Al2O3.

[0022] In yet another embodiment of the present invention, the heat-resistant coating may include a first heat-resistant coating coated on the battery housing, and a second heat-resistant coating coated on the first heat-resistant coating.

[0023] In yet another embodiment of the present invention, the heat-resistant coating may have a thickness of 5 μm to 40 μm.

[0024] Meanwhile, the present invention provides a battery pack, which includes at least one battery cell according to the above-described embodiment.

[0025] The present invention also provides a motor vehicle, the motor vehicle including at least one battery pack according to the above-described embodiments. [Effects of the Invention]

[0026] According to the present invention, in the event of a fire and / or explosion occurring inside the battery cell, damage to the side portion of the battery housing can be prevented.

[0027] More specifically, the present invention can prevent damage to the beading portion of the battery housing in the event of a fire and / or explosion inside the battery cell.

[0028] Furthermore, according to the present invention, damage to the side surface of the battery housing can be prevented, thereby preventing the spread of flames to the surrounding battery cells.

[0029] In another aspect, the present invention can prevent chain fires by preventing the flame from spreading to surrounding battery cells.

[0030] However, the effects obtained by the present invention are not limited to the effects described above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0031] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concepts of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a diagram illustrating a battery cell according to an embodiment of the present invention; [Figure 2] FIG. 2 is a vertical cross-sectional perspective view of FIG. [Figure 3] FIG. 2 is a longitudinal cross-sectional view of the battery cell of FIG. 1. [Figure 4] 1 is a diagram illustrating a state in which a heat-resistant coating according to an embodiment of the present invention is applied to a battery housing before deformation. [Figure 5] 10 is a diagram illustrating a state in which a heat-resistant coating according to an embodiment of the present invention is applied to a deformed battery housing. FIG. [Figure 6] FIG. 6 is an enlarged view of the periphery of the beading portion in FIG. 5. [Figure 7] 4A and 4B are diagrams illustrating a heat-resistant coating according to another embodiment of the present invention. [Figure 8] 1 is a diagram for explaining the shape of a heat-resistant coating according to an embodiment of the present invention. FIG. [Figure 9] FIG. 4 is a diagram illustrating the shape of a heat-resistant coating according to another embodiment of the present invention. [Figure 10] 10A and 10B are diagrams illustrating the shape of a heat-resistant coating according to still another embodiment of the present invention. [Figure 11] 10A and 10B are diagrams illustrating a process of damage to a battery housing due to a flame when a thermal event occurs inside a battery cell according to a comparative example of the present invention. [Figure 12] 10A and 10B are diagrams illustrating a process of preventing damage to a battery housing due to a fire when a thermal event occurs inside a battery cell according to an embodiment of the present invention. [Figure 13] 1 is a diagram illustrating a battery pack including a battery cell according to an embodiment of the present invention; [Figure 14] FIG. 14 is a diagram for explaining a vehicle including the battery pack of FIG. 13. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and claims should not be construed as being limited to their ordinary and dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical concept of the present invention, in accordance with the principle that the inventor himself can appropriately define the concept of terms in order to best describe the invention. Therefore, it should be understood that the configurations shown in the embodiments described in this specification are merely the most preferred embodiment of the present invention and do not represent the entire technical concept of the present invention, and therefore various equivalents and modifications that can be substituted therefor may exist at the time of filing this application.

[0034] In order to facilitate understanding of the invention, the accompanying drawings may not be drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used to refer to the same components in different embodiments.

[0035] When two comparison objects are identical, it means that they are "substantially identical." Therefore, "substantially identical" can include cases where there is a deviation that is considered to be a low level in the art, for example, a deviation within 5%. Furthermore, when a parameter in a given region is uniform, it can mean that the parameter is uniform on average.

[0036] Although terms such as "first" and "second" are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and it goes without saying that a first component is also a second component unless otherwise specified.

[0037] Throughout the specification, unless specifically stated to the contrary, each element may be singular or plural.

[0038] When any structure is disposed "on (or under)" a component or "above (or below)" a component, it can mean not only that the structure is disposed in contact with the upper surface (or lower surface) of the component, but also that other structures can be interposed between the component and any structure disposed on (or below) the component.

[0039] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the components can be directly coupled or connected to each other, but that other components may be "intervening" between the components, or that each component may be "coupled," "coupled," or "connected" via other components.

[0040] Throughout the specification, "A and / or B" means A, B, or A and B, unless otherwise specified, and "C through D" means at least C and at most D, unless otherwise specified.

[0041] Fig. 1 is a diagram for explaining a battery cell 1 according to one embodiment of the present invention, and Fig. 2 is a vertical cross-sectional perspective view of Fig. 1. Fig. 3 is a vertical cross-sectional view of the battery cell 1 of Fig. 1.

[0042] 1 to 3, a battery cell 1 according to one embodiment of the present invention includes an electrode assembly 10, a battery housing 20, and a current collector 30. The battery cell 1 may further include a housing cover 40 and / or a terminal 50 and / or a second current collector 60 and / or a seal gasket G1.

[0043] The housing cover 40 may have a vent 41 formed to prevent an increase in internal pressure due to gas generated inside the battery housing 20. The present invention is not limited by the shape of the battery and may be applied to batteries of other shapes, for example, prismatic batteries.

[0044] The electrode assembly 10 includes a first uncoated region 11 and a second uncoated region 12. More specifically, the electrode assembly 10 has a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis, defining a core and an outer circumferential surface. That is, the electrode assembly 10 according to the present invention may be a jelly roll-type electrode assembly 10. The electrode assembly 10 may be wound around a winding center hole H1. In this case, an additional separator may be provided on the outer circumferential surface of the electrode assembly 10 for insulation from the battery housing 20. The electrode assembly 10 may have a winding structure known in the art without limitation. Meanwhile, in the present invention, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate may be any active material known in the art without limitation.

[0045] 1 to 3, the battery housing 20 is a generally cylindrical container having an opening on one side and is made of a conductive metal material. The side surface of the battery housing 20 and the bottom surface opposite the opening are generally formed integrally. That is, the battery housing 20 generally has an open upper end in its height direction and a closed lower end. The bottom surface of the battery housing 20 may have a generally flat shape. The bottom surface of the battery housing 20 may constitute an outer surface 20b of a closed portion. In this case, the outer surface 20b of the closed portion may function as a second electrode terminal. The battery housing 20 accommodates the electrode assembly 10 through an opening formed on one side in its height direction. The battery housing 20 may also accommodate an electrolyte through the opening.

[0046] The battery housing 20 may include a beading portion 21 formed at an end adjacent to an opening formed at an upper end of the battery housing 20. The battery housing 20 may further include a crimping portion 22 formed on the beading portion 21. At least a portion of the side surface of the battery housing 20 has an inwardly recessed shape. Specifically, the beading portion 21 has an inwardly recessed shape around the outer periphery of the battery housing 20 to a predetermined depth. More specifically, the beading portion 21 may have an inwardly recessed shape in a region between an opening formed on one side of the battery housing 20 and a receiving portion that receives the electrode assembly 10.

[0047] The beading portion 21 may provide a support surface on which at least a portion of the periphery of the current collector 30 (described later) may be seated and coupled. That is, at least a portion of the periphery of the current collector 30 and / or the periphery of the housing cover 40 may be seated on the upper surface of the beading portion 21. In order to stably support at least a portion of the periphery of the current collector 30, the upper surface of the beading portion 21 may have a shape that extends along a direction approximately parallel to the lower surface of the battery housing 20, i.e., along a direction approximately perpendicular to the sidewall of the battery housing 20.

[0048] In one embodiment of the present invention, at least a portion of the inner surface of the battery housing 20 may be coated with a heat-resistant coating C.

[0049] For example, referring to FIGS. 2 and 3 , the heat-resistant coating C may be configured to cover at least a portion of the inner surface of the battery housing 20. The heat-resistant coating C may be, for example, a thin film coating having a heat resistance function. The heat-resistant coating C may be applied to an area where an internal flame concentrates when a thermal event occurs inside the battery cell 1. The heat-resistant coating C may have heat resistance and chemical resistance. That is, the heat-resistant coating C may be configured to meet predetermined standards for heat resistance and chemical resistance. For example, the heat-resistant coating C may be configured to meet predetermined standards in a CV test that tests for electrolyte side reactions within the operating voltage range of the battery cell 1 and an HF test that tests for the generation of HF, a byproduct generated when the internal material of the battery cell 1 reacts with the electrolyte and that reduces cell safety. In particular, the heat-resistant coating C may be configured to prevent side rupture due to an internal flame inside the battery cell 1. Accordingly, the heat-resistant coating C may be provided on at least a portion of the inner surface of the battery housing 20.

[0050] According to the above-described configuration, the heat-resistant coating C is provided on the inner surface of the battery housing 20, which can effectively prevent lateral rupture even if a thermal event occurs inside the battery cell 1. This can prevent a single cell ignition from leading to a chain reaction explosion.

[0051] In another aspect of the present invention, the beading portion 21 may be configured to include an upper surface located above the innermost point of the indentation and a lower surface located below the innermost point of the indentation.

[0052] For example, referring to FIG. 3, the beading portion 21 may have a recessed shape around the outer periphery of the battery housing 20 to a predetermined depth, with an upper surface positioned above and a lower surface positioned below the innermost point. The upper surface may include a flat section. Meanwhile, the lower surface may include a flat section. The flat section may extend in a direction perpendicular to the winding axis direction of the electrode assembly 10 and be flat. In one embodiment, as shown in FIG. 3, the upper surface and the lower surface of the beading portion 21 may have symmetrical shapes with respect to a virtual plane passing through the innermost point of the beading portion 21. Alternatively, in another embodiment, as shown in FIG. 5, the upper surface and the lower surface of the beading portion 21 may have asymmetrical shapes with respect to a virtual plane passing through the innermost point of the beading portion 21.

[0053] FIG. 4 is a diagram illustrating a state in which a heat-resistant coating C according to one embodiment of the present invention is applied to a battery housing 20 before deformation, and FIG. 5 is a diagram illustrating a state in which a heat-resistant coating C according to one embodiment of the present invention is applied to a battery housing 20 after deformation.

[0054] 4 and 5, after the electrode assembly 10 is inserted, the battery housing 20 may undergo a beading portion 21 forming process, in which at least a portion of the outer circumferential surface of the battery housing 20 is recessed inward. Meanwhile, the heat-resistant coating C may be applied to the inner surface of the battery housing 20 before the beading portion 21 forming process. The heat-resistant coating C may be formed at a location spaced a predetermined distance D from the open end of the battery housing 20. For example, referring to FIG. 4, when the total height L1 of the battery housing 20 before deformation is 100%, the heat-resistant coating C may be formed at a location spaced about 10% of the total height L1 of the battery housing 20 before deformation from the open end of the upper part of the battery housing 20. In one embodiment, the heat-resistant coating C may be formed at a location spaced about 9.76% of the total height L1 of the battery housing 20 before deformation from the open end of the upper part of the battery housing 20. Here, "deformation" refers to the beading portion 21 forming process.

[0055] In another aspect of the present invention, the heat-resistant coating C may be provided to have a width L2 of approximately 24% or more of the total height L1 of the battery housing 20 before deformation. In one embodiment, the heat-resistant coating C may be provided to have a width L2 of approximately 24.68% or more of the total height L1 of the battery housing 20 before deformation. Therefore, the lower end of the heat-resistant coating C may be configured to be located at a point away from the upper open end of the battery housing 20 that is approximately 35% or more of the total height L1 of the battery housing 20 before deformation.

[0056] Preferably, the heat-resistant coating C may be applied to a position where flames are concentrated inside the battery housing 20. As a result, the length N from the lower end of the heat-resistant coating C to the bottom of the battery housing 20 may be less than approximately 64.64% of the total height L1 of the battery housing 20 before deformation.

[0057] Meanwhile, in another embodiment, the width of the heat-resistant coating C may be further increased. That is, an embodiment is possible in which the lower end of the heat-resistant coating C extends to the closed portion at the bottom of the battery housing 20. In this case, the heat-resistant coating C can cover most of the inner surface of the battery housing 20, thereby further improving the effect of preventing side rupture, in which the side of the battery housing 20 is damaged, even if a thermal event such as a fire and / or explosion occurs inside the battery cell 1. That is, the heat-resistant coating C may be provided from the open end at the top of the battery housing 20 to a point 100% full. In this case, an embodiment may be possible in which the heat-resistant coating C continues to the lower end of the battery housing 20.

[0058] Referring to FIG. 5 , which shows the state after the beading portion 21 formation process, the heat-resistant coating C may be configured to cover at least a portion of the area extending from the innermost recess of the beading portion 21 in the direction opposite the opening. For example, referring to FIG. 5 , if a virtual plane passing through the innermost point of the beading portion 21, i.e., a horizontally extending plane, is defined as plane X, the heat-resistant coating C may be configured to extend downward from the point where plane X intersects with the battery housing 20. Here, "deformation" refers to the formation of the beading portion 21. The overall height L3 of the battery housing 20 after deformation is smaller than the overall height L1 of the battery housing 20 before deformation.

[0059] Generally, when a thermal event such as a fire and / or explosion occurs inside a battery cell 1, the flame is ejected to the outside through the vent. If the flame contacts the beading portion 21, which is recessed toward the inside of the battery housing 20, the flame at the beading portion 21 may damage the battery housing 20, potentially causing a lateral rupture of the side of the battery housing 20, particularly the beading portion 21. This abnormal ignition may spread the flame to the surrounding battery cells 1, significantly increasing the possibility of a chain reaction of fires and / or explosions. Therefore, it is desirable to improve heat resistance, particularly around the beading portion 21. In the present invention, by applying a heat-resistant coating C to the beading portion 21, damage to the beading portion 21 can be effectively prevented even if a fire inside the battery cell 1 contacts the beading portion 21.

[0060] FIG. 6 is an enlarged view of the beading portion 21 and its periphery in FIG. 5, and FIG. 7 is a view for explaining a heat-resistant coating C according to another embodiment of the present invention.

[0061] 6, the heat-resistant coating C may be configured to cover at least a portion of the beading portion 21. Desirably, the heat-resistant coating C may be configured to cover at least a portion of the lower surface of the beading portion 21. For example, the heat-resistant coating C may be configured to cover at least a portion of the area extending from the innermost point of the beading portion 21 inwardly recessed to the opposite direction from the open portion. More specifically, the heat-resistant coating C may be configured to cover at least a portion of the area extending downward from the innermost point of the beading portion 21 inwardly recessed.

[0062] As described above, when a thermal event occurs inside the battery cell 1, the flame generally advances toward the lower surface of the beading portion 21, and therefore, of the upper and lower surfaces of the beading portion 21, the lower surface is relatively more vulnerable to the flame. When a thermal event occurs in the electrode assembly 10, the flame generated in the electrode assembly 10 generally advances upward. That is, an edge flow occurs inside the battery housing 20, in which the flame generated in the electrode assembly 10 flows upward along the inner surface of the battery housing 20. Therefore, it is preferable to apply the heat-resistant coating C preferentially to the lower surface of the beading portion 21.

[0063] In another embodiment, the heat-resistant coating C may be configured to cover at least a portion of an area extending in a direction opposite to the open portion from a point where the flat section of the upper surface of the beading portion 21 starts. More specifically, the heat-resistant coating C may be configured to cover at least a portion of an area extending downward from a point where the flat section of the upper surface of the beading portion 21 starts.

[0064] For example, referring to FIG. 7 , the upper surface of the beading portion 21 may include a flat section. The flat section may extend in a direction perpendicular to the winding axis direction of the electrode assembly 10 and be flat. When the imaginary plane on which the flat section of the upper surface of the beading portion 21 extends is defined as plane Y, the heat-resistant coating C may extend downward from the point where plane Y intersects with the battery housing 20. That is, when a flame travels from the bottom to the top, the flame may be blocked by the current collecting plate, which may prolong the time the flame remains near the beading portion 21. Therefore, it is preferable that the heat-resistant coating C cover not only the bottom surface of the beading portion 21 but also the side surfaces. The side surfaces of the beading portion 21 refer to areas including the innermost point of the beading portion 21.

[0065] 1 to 3, in another aspect of the present invention, a current collector 30 according to an embodiment of the present invention is accommodated inside a battery housing 20 and is electrically connected to the electrode assembly 10 and the battery housing 20. That is, the current collector 30 electrically connects the electrode assembly 10 and the battery housing 20. The current collector 30 includes a support portion 31 located on one side of the electrode assembly 10, a tab coupling portion 32 extending from the support portion 31 and coupled to the first uncoated portion 11, and a housing coupling portion 33 extending from the support portion 31 and coupled to the inner surface of the battery housing 20. The current collector 30 may include a hole H2 in the center for injecting an electrolyte.

[0066] The housing coupling portion 33 may include a contact portion 33a coupled to the inner surface of the battery housing 20 and a connection portion 33b connecting the support portion 31 and the contact portion 33a. In one embodiment of the present invention, the tab coupling portion 32 may have a width greater than that of the connection portion 33b. In another embodiment of the present invention, the contact portion 33a may have a width greater than that of the connection portion 33b.

[0067] The contact portion 33a is coupled to the inner surface of the battery housing 20. Preferably, the contact portion 33a may be coupled to the beading portion 21 of the battery housing 20. In this case, for stable contact and coupling, both the beading portion 21 and the contact portion 33a may have a shape that extends in a direction substantially parallel to the lower surface of the battery housing 20, i.e., in a direction substantially perpendicular to the sidewall of the battery housing 20.

[0068] In another embodiment of the present invention, the housing coupling portion 33 of the current collector 30 may be welded to the beading portion 21 while being placed on the beading portion 21. At this time, the contact portion 33a of the housing coupling portion 33 may be coupled to the beading portion 21. With this structure, the contact portion 33a physically covers the upper surface of the beading portion 21. However, the side and lower surfaces of the beading portion 21, which are not physically protected by the contact portion 33a, are vulnerable to fire. Therefore, it is more preferable that the heat-resistant coating C be configured to extend downward from the point where the flat section of the upper surface of the beading portion 21 begins.

[0069] In one embodiment of the present invention, the heat-resistant coating C may include a resin and ceramic particles.

[0070] In this case, the resin may be configured to include at least one of PI, PAI, silicone, and epoxide. Meanwhile, the ceramic may be configured to include at least one of TiO2 and Al2O3. For example, when the heat-resistant coating C includes TiO2, it was confirmed that the time to develop a hole in the side wall of the battery housing 20 increased from an average of 14.0 seconds to 38.8 seconds in a flame evaluation.

[0071] On the other hand, it has been confirmed that when the heat-resistant coating C of the present invention contains silicone, its chemical resistance is improved. In particular, it has been confirmed that changing the composition of the silicone coating (increasing the amount of organic components) improves its chemical resistance. However, it goes without saying that the types of resin and ceramic contained in the heat-resistant coating C of the present invention are not limited to the above examples. The type of resin and / or ceramic can be selected based on heat resistance, chemical resistance, electrolyte stability, etc. In other words, the heat-resistant coating C can be configured to satisfy predetermined standard heat resistance conditions and predetermined standard chemical resistance conditions.

[0072] In another aspect of the present invention, the ceramic may be contained in the form of particles. In one embodiment, the heat-resistant coating C may be formed in a form in which ceramic particles are contained in a resin base. That is, the heat-resistant coating C may contain ceramic particles. In this case, the melting point of the ceramic particles may be, for example, about 1000°C or higher.

[0073] When the melting point of the ceramic particles contained in the heat-resistant coating C is about 1000°C or higher, the possibility of side rupture is significantly reduced. Furthermore, when the heat-resistant coating C is configured in the form of ceramic particles contained in a resin base as described above, the ceramic content can be easily adjusted, thereby improving manufacturing convenience.

[0074] In another embodiment of the present invention, the heat-resistant coating C may be configured to include a first heat-resistant coating C coated on the battery housing 20 and a second heat-resistant coating C coated on the first heat-resistant coating C.

[0075] That is, the heat-resistant coating C may be configured in a form in which a plurality of coatings are overlapped. Furthermore, the heat-resistant coating C may further include a third heat-resistant coating C. In addition, the heat-resistant coating C may further include up to a kth heat-resistant coating C, which is applied in the kth order. In this case, the first heat-resistant coating C and the second heat-resistant coating C may be configured to be different types from each other.

[0076] This structure allows for improved heat and chemical resistance through the application of multiple coatings. Furthermore, by applying multiple heat-resistant coatings C with different compositions, it is possible to overcome the limitations of the heat and chemical resistance of a single material.

[0077] In yet another embodiment of the present invention, the heat-resistant coating C may be configured to have a thickness of about 5 μm to 40 μm. Desirably, the heat-resistant coating C may be configured to have a thickness of about 15 μm to 30 μm.

[0078] For example, if the thickness of the heat-resistant coating C is less than about 5 μm, there is a high possibility that heat resistance will not be ensured. On the other hand, if the thickness of the heat-resistant coating C is greater than about 40 μm, the coating becomes too thick, and the internal space of the battery housing 20 becomes too narrow. This inevitably reduces the volume of the electrode assembly 10 housed inside the battery cell 1, ultimately resulting in a decrease in energy density. Therefore, the heat-resistant coating C of the present invention is preferably configured to have a thickness of about 5 μm to 40 μm, and more preferably to have a thickness of about 15 μm to 30 μm.

[0079] Fig. 8 is a diagram illustrating the shape of a heat-resistant coating C according to one embodiment of the present invention, Fig. 9 is a diagram illustrating the shape of a heat-resistant coating C according to another embodiment of the present invention, and Fig. 10 is a diagram illustrating the shape of a heat-resistant coating C according to yet another embodiment of the present invention.

[0080] 8, the heat-resistant coating C may be configured to have a generally strip-like shape with a certain width. That is, the heat-resistant coating C may be configured in a strip-like shape extending downward to a certain length L2 from a point spaced a certain distance D from an opening formed on one side of the battery housing 20 in the height direction.

[0081] In another embodiment, the heat-resistant coating C may be configured to have a partially coated shape within a region extending downward from a point spaced a predetermined distance D from an opening formed on one side of the battery housing 20 in the height direction.

[0082] For example, referring to FIG. 9, the heat-resistant coating C may be configured to have a substantially diagonal line pattern. Alternatively, referring to FIG. 10, the heat-resistant coating C may be configured to have a substantially lattice pattern. As such, the shape of the heat-resistant coating C is not limited to a stripe shape and may be configured in various shapes. Alternatively, although not shown in the drawings, the upper and lower edges of the heat-resistant coating C may be configured to have curved shapes. That is, the heat-resistant coating C is provided on an area of ​​the battery housing 20 that is easily accessible to flames generated inside the battery housing 20, and may be applied in various shapes depending on the situation. For example, the heat-resistant coating C may be applied by covering the uncoated area with masking tape and then applying a coating agent. In this case, the shape of the heat-resistant coating C can be varied depending on the punched shape of the masking tape. As long as the masking tape can be applied to the inner wall of the battery housing 20, the heat-resistant coating C may be applied in various shapes, such as horizontal or vertical, linear or curved.

[0083] According to this configuration, the amount of material used for the heat-resistant coating C can be reduced while the heat-resistant performance of the heat-resistant coating C can be significantly ensured.

[0084] FIG. 11 is a diagram illustrating the process of damage to the battery housing 20 due to a flame when a thermal event occurs inside the battery cell 1 according to a comparative example of the present invention, and FIG. 12 is a diagram illustrating the process of preventing damage to the battery housing 20 due to a flame when a thermal event occurs inside the battery cell 1 according to one embodiment of the present invention.

[0085] 11, when a thermal event occurs in a conventional battery cell 1, an edge flow of the internal flame occurs, causing the flame to contact the underside and side of the beading portion 21 in a concentrated manner. This can damage the underside and / or side of the beading portion 21, creating a hole in the sidewall or beading portion 21 of the battery cell 1, potentially causing a side rupture in which flames are ejected toward the hole. In this case, not only the battery cell 1 where the thermal event occurred, but also other battery cells 1 located around the battery cell 1 are affected, potentially causing a chain reaction of fires.

[0086] 12, a heat-resistant coating C is applied to a battery cell 1 according to one embodiment of the present invention, and more specifically, the heat-resistant coating C is applied to the beading portion 21, thereby effectively preventing damage to the side surface and / or the beading portion 21 of the battery cell 1. More specifically, referring to Fig. 12, a flame contacts the lower surface of the beading portion 21, but the heat-resistant coating C protects the lower surface of the beading portion 21, thereby effectively preventing the flame from damaging the beading portion 21 and / or the side surface of the battery cell 1. This makes it possible to prevent a chain fire phenomenon.

[0087] FIG. 13 is a diagram illustrating a battery pack 3 including a battery cell 1 according to one embodiment of the present invention.

[0088] 13, a battery pack 3 according to one embodiment of the present invention includes a battery assembly in which a plurality of battery cells 1 according to one embodiment of the present invention are electrically connected, as described above, and a pack housing 2 that accommodates the battery assembly. For ease of illustration, components such as bus bars for electrical connections, a cooling unit, and power terminals are omitted from the drawings of the present invention.

[0089] FIG. 14 is a diagram illustrating an automobile 5 including the battery pack 3 of FIG.

[0090] 14, an automobile 5 according to an embodiment of the present invention is, for example, an electric automobile, a hybrid automobile, or a plug-in hybrid automobile, and includes a battery pack 3 according to an embodiment of the present invention. The automobile 5 includes a four-wheeled automobile and a two-wheeled automobile. The automobile 5 operates by receiving power from the battery pack 3 according to an embodiment of the present invention.

[0091] Although the present invention has been described above using limited embodiments and drawings, it goes without saying that the present invention is not limited thereto, and that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims set forth below. [Explanation of symbols]

[0092] 1 battery cell 2-pack housing 3 Battery Pack 5. Automobiles 10 Electrode assembly 11 First plain section 12 Second plain section 20 Battery Housing 20b Outer surface of closure 21 Beading section 22 Crimping section 30 Current collector 31 Support part 33 Housing joint 40 Housing cover 41 Vent C Heat-resistant coating G1 seal gasket H1 Winding center hole H2 hole

Claims

1. an electrode assembly including a first electrode, a second electrode, and a separator interposed therebetween; a battery housing that accommodates the electrode assembly through an opening formed on one side thereof, At least a portion of the inner surface of the battery housing is coated with a heat-resistant coating.

2. The battery housing includes: The battery cell according to claim 1 , wherein at least a portion of the side surface includes an inwardly recessed beading portion.

3. The battery cell of claim 2 , wherein the heat-resistant coating covers at least a portion of the beading portion.

4. The beading portion is an upper surface located above the innermost point of the inward recess; a lower surface located below the innermost point of the inward recess; The battery cell of claim 2 or 3, comprising:

5. The battery cell according to claim 4 , wherein the heat-resistant coating covers a lower surface of the beading portion.

6. The battery cell according to claim 1 , wherein the cover area of ​​the heat-resistant coating has a width in the winding axis direction that is 24% or more of the total height of the battery housing before deformation.

7. The battery cell according to claim 2 or 3, wherein the heat-resistant coating covers at least a portion of an area extending from an innermost point recessed inwardly of the beading portion in a direction opposite to the opening.

8. The battery cell according to claim 2 or 3, wherein the heat-resistant coating covers at least a portion of an area extending from a point where a flat section of an upper surface of the beading portion starts in a direction opposite to the opening.

9. The battery cell of claim 1 , wherein the heat-resistant coating comprises at least one of PI, PAI, silicone, and epoxide.

10. The battery cell of claim 1 , wherein the heat-resistant coating comprises ceramic particles.

11. The heat-resistant coating is TiO ２ and Al ２ O ３ The battery cell according to claim 1 , comprising at least one of:

12. The heat-resistant coating is a first heat-resistant coating coated on the battery housing; a second heat-resistant coating coated on the first heat-resistant coating; The battery cell of claim 1 , comprising:

13. The battery cell according to any one of claims 1 to 3, wherein the heat-resistant coating has a thickness of 5 μm to 40 μm.

14. A battery pack comprising at least one battery cell according to any one of claims 1 to 3.

15. A motor vehicle comprising at least one battery pack according to claim 14.

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