Battery cell, battery pack including battery cell and vehicle

Abstract

A battery cell according to one embodiment of the present invention comprises: an electrode assembly comprising a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode; and a battery case for accommodating the electrode assembly through an opening formed on one side thereof, in which at least one region of an inner surface of the battery case is coated with a heat-resistant coating.

Description

Technical Field

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

[0002] This application claims priority to Korean Patent Application No. 10-2023-0081280 filed in Korea on June 23, 2023, and Korean Patent Application No. 10-2024-0075265 filed in Korea on June 10, 2024, the disclosures of which are incorporated herein by reference. Background Art

[0003] Since secondary batteries can be easily applied to various types of products and have electrical properties such as high energy density, secondary batteries are generally used not only in portable devices, but also in electric vehicles (EV) or hybrid electric vehicles (HEV) and electric scooters powered by electric drive sources. Secondary batteries can significantly reduce the use of fossil fuels. In addition to the main advantages, another advantage is that secondary batteries do not produce by-products due to the use of energy. Due to these advantages, secondary batteries are receiving attention as a more environmentally friendly and energy-saving new energy source.

[0004] The types of secondary batteries widely used at present include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. The unit secondary battery cell (i.e., unit battery cell) has an operating voltage of about 2.5V to 4.5V. Therefore, when a higher output voltage is required, a plurality of battery cells can be connected in series to form a battery pack. In addition, according to the required charge / discharge capacity of the battery pack, a battery pack can be formed by connecting a plurality of battery cells in parallel. Therefore, the number of battery cells included in the battery pack can be set differently according to the required output voltage or charge / discharge capacity.

[0005] Meanwhile, in existing battery cell structures, when a thermal event such as a fire and / or explosion occurs, in some cases, the flame is not released into the atmosphere through a vent, but may burst from the side wall of the battery can. Therefore, a safety reinforcement design for the battery cell is required to prevent the side from rupturing, thereby preventing the spread of fire and / or explosion caused by the flame propagating to adjacent battery cells. Summary of the invention

[0006] Technical issues

[0007] The present disclosure is directed to preventing damage to the sides of a battery case when an event such as a fire and / or explosion occurs in a battery cell.

[0008] More specifically, the present disclosure is directed to preventing damage to a curled edge portion of a battery case when an incident such as a fire and / or explosion occurs in a battery cell.

[0009] Additionally, the present disclosure is directed to preventing flame propagation to adjacent battery cells by preventing damage to the sides of the battery casing.

[0010] On the other hand, the present disclosure is directed to preventing the spread of fire by preventing the flames from propagating to adjacent battery cells.

[0011] The technical problems to be solved by the present disclosure are not limited to the above-mentioned problems, and those skilled in the art will clearly understand these and other problems from the following description.

[0012] Technical Solution

[0013] In order to solve the above problems, a battery cell according to an embodiment of the present disclosure includes: an electrode assembly, the electrode assembly including a first electrode, a second electrode and a separator inserted between the first electrode and the second electrode; and a battery case, the battery case accommodating the electrode assembly through an opening formed on one side, wherein at least a portion of the inner surface of the battery case is coated with a heat-resistant coating.

[0014] In one aspect of the present disclosure, the battery case may include a bead portion recessed inward from at least a portion of the one side.

[0015] Preferably, the heat-resistant coating may cover at least a portion of the curling portion.

[0016] In another aspect of the present disclosure, the curling portion may include an upper surface located at a higher position than an innermost point of the recess; and a lower surface located at a lower position than the innermost point of the recess.

[0017] Preferably, the heat-resistant coating may cover the lower surface of the curling portion.

[0018] In another aspect of the present disclosure, in the first item,

[0019] The length of the covered region of the heat-resistant coating in the winding axis direction may have a width of 24% or more of the total length of the battery case before deformation.

[0020] In one aspect of the present disclosure, the heat-resistant coating may cover at least a portion of a region extending from an innermost point of the depression of the curling portion in a direction opposite to the opening portion.

[0021] In another aspect of the present disclosure, the heat-resistant coating may cover at least a portion of a region extending from a starting point of a flat region of an upper surface of the beaded portion in a direction opposite to the opening portion.

[0022] In one aspect of the present disclosure, the heat-resistant coating may include at least one of PI, PAI, silicone, or epoxy.

[0023] For example, the heat-resistant coating may include ceramic particles.

[0024] In another aspect of the present disclosure, the heat-resistant coating may include at least one of TiO 2 or Al 2 O 3 .

[0025] In another aspect of the present disclosure, the heat-resistant coating may include: a first heat-resistant coating, the first heat-resistant coating being coated on the battery case; and a second heat-resistant coating, the second heat-resistant coating being coated on the first heat-resistant coating.

[0026] In another aspect of the present disclosure, the heat-resistant coating may have a thickness of 5 micrometers to 40 micrometers.

[0027] Meanwhile, the present disclosure provides a battery pack including at least one battery cell according to the above-mentioned embodiments.

[0028] Furthermore, the present disclosure provides a vehicle including at least one battery pack according to the above-described embodiments.

[0029] Beneficial Effects

[0030] According to the present disclosure, when an event such as a fire and / or an explosion occurs in a battery cell, damage to the side surface of the battery case can be prevented.

[0031] More specifically, according to the present disclosure, when an event such as a fire and / or an explosion occurs in a battery cell, damage to a curled edge portion of a battery case can be prevented.

[0032] Furthermore, according to the present disclosure, it is possible to prevent flame from propagating to adjacent battery cells by preventing damage to the sides of the battery case.

[0033] On the other hand, according to the present disclosure, it is possible to prevent the spread of fire by preventing the flame from propagating to adjacent battery cells.

[0034] However, the effects obtainable by the present disclosure are not limited to the above-described effects, and those skilled in the art will clearly understand these and other effects from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the following detailed description, serve to provide a better understanding of the technical aspects of the present disclosure, and therefore, the present disclosure should not be construed as being limited to the accompanying drawings.

[0036] Figure 1 is a schematic diagram showing a battery cell according to an embodiment of the present disclosure.

[0037] Figure 2 yes Figure 1Longitudinal cross-sectional perspective view.

[0038] Figure 3 yes Figure 1 Longitudinal cross-section of a battery cell.

[0039] Figure 4 is a schematic diagram showing a heat-resistant coating according to an embodiment of the present disclosure applied to a battery case before deformation.

[0040] Figure 5 is a schematic diagram showing a heat-resistant coating according to an embodiment of the present disclosure applied to a battery case after deformation.

[0041] Figure 6 yes Figure 5 An enlarged view of the curled edge and its vicinity.

[0042] Figure 7 is a schematic diagram of a heat-resistant coating according to another embodiment of the present disclosure.

[0043] Figure 8 is a schematic diagram showing the shape of a heat-resistant coating according to an embodiment of the present disclosure.

[0044] Fig. 9 is a schematic diagram illustrating the shape of a heat-resistant coating according to another embodiment of the present disclosure.

[0045] Fig.10 is a schematic diagram illustrating the shape of a heat-resistant coating according to still another embodiment of the present disclosure.

[0046] Fig.11 is a schematic diagram illustrating damage to a battery case caused by flame when a thermal event occurs in a battery cell according to a comparative example of the present disclosure.

[0047] Fig.12 is a schematic diagram illustrating preventing damage to a battery case caused by flame when a thermal event occurs in a battery cell according to an embodiment of the present disclosure.

[0048] Fig.13 is a schematic diagram illustrating a battery pack including a battery cell according to an embodiment of the present disclosure.

[0049] Fig.14 It is shown that Fig.13 Schematic diagram of a vehicle with a battery pack. DETAILED DESCRIPTION

[0050] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before describing, it should be understood that the terms or words used in the specification and the appended claims should not be interpreted as limited to the general meaning and dictionary meaning, but on the basis of the principle that the inventor is allowed to appropriately define the terms for the best interpretation, based on the meaning and concept corresponding to the technical aspects of the present disclosure. Therefore, the embodiments described herein and the illustrations in the accompanying drawings are provided to describe the exemplary embodiments of the present disclosure by way of example, and are not intended to fully describe the technical aspects of the present disclosure, so it should be understood that various other equivalents and modifications may be proposed to it when filing a patent application.

[0051] In addition, to help understand the present disclosure, the drawings are not drawn to scale and the sizes of some elements may be exaggerated. Likewise, the same reference numerals may be attached to the same elements in different embodiments.

[0052] The term "same" may mean "substantially the same". Thus, "substantially the same" may include being the same but having, for example, a difference of 5% or less that is considered a low level in the corresponding technical field. In addition, when a parameter is referred to as being uniform in a certain area, it may mean that the parameter is uniform in a general sense.

[0053] The terms "first", "second", etc. are used to describe different elements, but these elements are not limited by these terms. These terms are used to distinguish one element from another element, and unless otherwise specified, the first element may be the second element.

[0054] Throughout the specification, unless otherwise specified, each element may be in the singular or in the plural.

[0055] It will be understood that when an element is referred to as being “on (or under)”, it may exist on the upper surface (or lower surface), or intermediate elements may exist between the element and other elements disposed on (or under) the element.

[0056] It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, the element may be directly connected to the other element, but each element may be “connected” or “coupled” to each other through another element, or intervening elements may be present.

[0057] In the specification, “A and / or B” means A or B or both unless otherwise specified, and “C to D” means C or more and D or less unless otherwise specified.

[0058] Figure 1 is a schematic diagram showing a battery cell 1 according to an embodiment of the present disclosure, and Figure 2 yes Figure 1Longitudinal cross-sectional perspective view. Figure 3 yes Figure 1 A longitudinal cross-sectional view of a battery cell 1 is shown.

[0059] Reference Figures 1 to 3 , the battery cell 1 according to an embodiment of the present disclosure includes an electrode assembly 10, a battery case 20, and a current collector 30. The battery cell 1 may further include a case cover 40 and / or a terminal 50 and / or a second current collector 60 and / or a sealing gasket G1.

[0060] The case cover 40 may include a vent 41 to prevent an increase in internal pressure due to gas generated in the battery case 20. The present disclosure is not limited by the shape of the battery and may be applied to batteries of other shapes (eg, square batteries).

[0061] The electrode assembly 10 includes a first uncoated portion 11 and a second uncoated portion 12. More specifically, the electrode assembly 10 has a structure in which the first electrode and the second electrode are wound around a winding axis, and a separator is interposed between the first electrode and the second electrode, thereby defining a core portion and a peripheral surface. That is, the electrode assembly 10 applied to the present disclosure may be a core-wound electrode assembly 10. The electrode assembly 10 may be wound around the winding center hole H1. In this case, the electrode assembly 10 may further include an additional separator located on the peripheral surface to be insulated from the battery case 20. The electrode assembly 10 may have any known winding structure without limitation. At the same time, in the present disclosure, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate may include any known active material without limitation.

[0062] Reference Figures 1 to 3 The battery case 20 is a generally cylindrical container having an opening on one side and is made of a conductive metal. The side surface of the battery case 20 and the lower surface on the opposite side of the opening are generally formed integrally. That is, the battery case 20 generally has an open top and a closed bottom in the height direction. The lower surface of the battery case 20 may have a generally flat shape. The lower surface of the battery case 20 may form an outer surface 20a of the closed portion. In this case, the outer surface 20a of the closed portion may be used as a second electrode terminal. The battery case 20 accommodates the electrode assembly 10 by forming an opening on one side in the height direction. The battery case 20 may simultaneously accommodate the electrolyte through the opening.

[0063] The battery case 20 may include a curling portion 21 located at an end portion adjacent to the opening portion at the top of the battery case 20. The battery case 20 may also include a clamping portion 22 located on the curling portion 21. At least a portion of the side of the battery case 20 is recessed inwardly. Specifically, the curling portion 21 has a shape that is recessed to a predetermined depth along the periphery from the outer peripheral surface of the battery case 20. More specifically, the curling portion 21 may be recessed inwardly from the area between the opening portion on one side of the battery case 20 and the accommodating portion that accommodates the electrode assembly 10.

[0064] The beading portion 21 may provide a support surface to which at least a portion of an edge of the current collector 30 described below is mounted and coupled. That is, at least a portion of an edge of the current collector 30 and / or an edge of the case cover 40 of the present disclosure may be mounted on the upper surface of the beading portion 21. In order to stably support at least a portion of the edge of the current collector 30, the upper surface of the beading portion 21 may extend in a direction substantially parallel to the lower surface of the battery case 20 (i.e., substantially perpendicular to the side wall of the battery case 20).

[0065] In one aspect of the present disclosure, at least a portion of the inner surface of the battery case 20 may be coated with a heat-resistant coating C.

[0066] For example, refer to Figure 2 and Figure 3 , the heat-resistant coating C may be configured to cover at least a portion of the inner surface of the battery case 20. The heat-resistant coating C may be, for example, a thin film coating having a heat-resistant function. When a thermal event occurs in the battery cell 1, the heat-resistant coating C may be applied to the area where the flame is concentrated. 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 heat resistance requirements and predetermined chemical resistance requirements. For example, the heat-resistant coating C may be configured to meet predetermined requirements in a CV test and an HF test, the CV test tests the electrolyte side reactions within the operating voltage range of the battery cell 1, and the HF test tests the byproducts produced by the reaction between the material in the battery cell 1 and the electrolyte solution and the generation of HF that reduces the stability of the cell. In particular, the heat-resistant coating C may be configured to prevent side ruptures caused by flames in the battery cell 1. Therefore, the heat-resistant coating C may be present in at least a portion of the inner surface of the battery case 20.

[0067] By the above configuration, the heat-resistant coating C exists on the inner surface of the battery case 20, and when a thermal event occurs in the battery cell 1, side rupture can be effectively prevented. Therefore, the spread of fire or explosion in the single cell can be prevented.

[0068] In another aspect of the present disclosure, the beaded portion 21 may include an upper surface located at a higher position than the innermost point of the recess and a lower surface located at a lower position than the innermost point of the recess.

[0069] For example, refer to Figure 3 , the curling portion 21 may be recessed from the outer peripheral surface of the battery case 20 along the periphery to a predetermined depth, and in this case, may have an upper surface located at an upper position and a lower surface located at a lower position relative to the innermost point. In this case, the upper surface may include a flat area. At the same time, the lower surface may include a flat area. The flat area may extend in a direction perpendicular to the winding axis direction of the electrode assembly 10 and may be flat. As an embodiment, as Figure 3 As shown in FIG. 1 , the upper surface of the curling portion 21 and the lower surface of the curling portion 21 may have a symmetrical shape with respect to an imaginary plane passing through the innermost point of the curling portion 21. Alternatively, as another embodiment, Figure 5 As shown, the upper surface of the beaded portion 21 and the lower surface of the beaded portion 21 may have an asymmetrical shape with respect to an imaginary plane passing through the innermost point of the beaded portion 21 .

[0070] Figure 4 is a schematic diagram showing a heat-resistant coating C according to an embodiment of the present disclosure applied to a battery case 20 before deformation, and Figure 5 is a schematic diagram showing the heat-resistant coating C according to an embodiment of the present disclosure applied to the battery case 20 after deformation.

[0071] Reference Figure 4 and Figure 5 , after the electrode assembly 10 is inserted, the battery case 20 may undergo a process of forming a curling portion 21 that is recessed inward from at least a portion of the outer peripheral surface of the battery case 20. Meanwhile, before the process of forming the curling portion 21, a heat-resistant coating C may be applied to the inner surface of the battery case 20. In this case, the heat-resistant coating C may be disposed at a predetermined distance D from the opening of the battery case 20. For example, referring to Figure 4 , when the total length L1 of the battery case 20 before deformation is 100%, the heat-resistant coating C can be set at a position of about 10% of the total length L1 of the battery case 20 before deformation, away from the top open end of the battery case 20. As an embodiment, the heat-resistant coating C can be set at a position of about 9.76% of the total length L1 of the battery case 20 before deformation, away from the top open end of the battery case 20. Here, deformation refers to the process of forming the curling portion 21.

[0072] In another aspect of the present disclosure, the heat-resistant coating C may have a width L2 of about 24% or more of the total length L1 of the battery case 20 before deformation. As an embodiment, the heat-resistant coating C may have a width L2 of about 24.68% or more of the total length L1 of the battery case 20 before deformation. Therefore, the lower end of the heat-resistant coating C may be disposed away from the top open end of the battery case 20 at a position of about 35% or more of the total length L1 of the battery case 20 before deformation.

[0073] Preferably, the heat-resistant coating C may be applied to a location where flames concentrate within the battery case 20. Therefore, a length N from a lower end of the heat-resistant coating C to the bottom of the battery case 20 may be less than about 64.64% of a total length L1 of the battery case 20 before deformation.

[0074] At the same time, as another embodiment, the width of the heat-resistant coating C can be further increased. That is, an embodiment in which the lower end of the heat-resistant coating C extends to the closed portion on the bottom of the battery case 20 is possible. In this case, because the heat-resistant coating C can cover most of the inner surface of the battery case 20, when a thermal event such as a fire and / or explosion occurs in the battery cell 1, the effect of preventing the side rupture or side damage of the battery case 20 can be further improved. That is, the heat-resistant coating C can extend from the top open end of the battery case 20 to the 100% point. In this case, the heat-resistant coating C can extend to the lower end of the battery case 20.

[0075] Next, refer to Figure 5 , which shows that after the process of forming the curling portion 21, the heat-resistant coating C can be configured to cover at least a portion of the area extending from the innermost point of the depression of the curling portion 21 in the direction opposite to the opening. Figure 5 , when a plane extending in the horizontal direction (i.e., an imaginary plane passing through the innermost point of the curling portion 21) is a plane X, the heat-resistant coating C may extend downward from the point where the plane X intersects the battery case 20. Here, deformation refers to the formation of the curling portion 21. The total length L3 of the battery case 20 after deformation is less than the total length L1 of the battery case 20 before deformation.

[0076] Typically, when a thermal event such as a fire and / or explosion occurs in a battery cell 1, the flame is released into the atmosphere through the ventilation portion. In this process, when the flame contacts the inwardly recessed curling portion 21 of the battery housing 20, the battery housing 20 is likely to be damaged by the flame at the curling portion 21, thereby causing the side of the battery housing 20 (especially the side at the curling portion 21) to rupture. In such a fire situation, the risk of flame propagation to adjacent battery cells 1 and the spread of fire and / or explosion is very high. Therefore, it is preferred to increase the heat resistance at or around the curling portion 21. By applying a heat-resistant coating C to the curling portion 21, the present disclosure can effectively prevent damage to the curling portion 21 when the flame inside the battery cell 1 contacts the curling portion 21.

[0077] Figure 6 yes Figure 5 An enlarged view of the curling portion 21 and its vicinity, and Figure 7 is a schematic diagram of a heat-resistant coating C according to another embodiment of the present disclosure.

[0078] Reference Figure 6 , the heat-resistant coating C may be configured to cover at least a portion of the curling portion 21. Preferably, the heat-resistant coating C may be configured to cover at least a portion of the lower surface of the curling portion 21. For example, the heat-resistant coating C may be configured to cover at least a portion of an area extending from the innermost point of the depression of the curling portion 21 in a direction opposite to the opening. More specifically, the heat-resistant coating C may be configured to cover at least a portion of an area extending downward from the innermost point of the depression of the curling portion 21.

[0079] As described above, generally, when a thermal event occurs in the battery cell 1, the flame moves toward the lower surface of the curling portion 21, so the lower surface of the curling portion 21 is more susceptible to the flame than the upper surface. Generally, the thermal event occurs in the electrode assembly 10, and the flame generated from the electrode assembly 10 moves upward. That is, edge flow occurs in the battery case 20 (that is, the flame generated from the electrode assembly 10 flows upward along the inner surface of the battery case 20). Therefore, preferably, the heat-resistant coating C is first applied to the lower surface of the curling portion 21.

[0080] As 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 opening portion from a starting point of the flat area on the upper surface of the curling portion 21. More specifically, the heat-resistant coating C may be configured to cover at least a portion of an area extending downward from a starting point of the flat area on the upper surface of the curling portion 21.

[0081] For example, refer to Figure 7, the upper surface of the curling portion 21 may include a flat area. In this case, the flat area may extend in a direction perpendicular to the winding axis direction of the electrode assembly 10 and may be flat. In this case, when the imaginary plane extending from the flat area of ​​the upper surface of the curling portion 21 is plane Y, the heat-resistant coating C may extend downward from the point where plane Y intersects with the battery case 20. That is, when the flame moves upward, the flame may be blocked by the current collector and stay longer at or near the curling portion 21. Therefore, in addition to the lower surface of the curling portion 21, the heat-resistant coating C preferably also covers the side. The side of the curling portion 21 refers to the area including the innermost point of the curling portion 21.

[0082] In another aspect of the present disclosure, referring again to Figures 1 to 3 , the current collector 30 according to an embodiment of the present disclosure is housed in the battery case 20, and is electrically connected to the electrode assembly 10 and is also electrically connected to the battery case 20. That is, the current collector 30 electrically connects the electrode assembly 10 to the battery case 20. The current collector 30 includes a support portion 31 located on one surface of the electrode assembly 10, a joint coupling portion 32 extending from the support portion 31 and coupled to the first non-coating portion 11, and a case coupling portion 33 extending from the support portion 31 and coupled to the inner surface of the battery case 20. The current collector 30 may include a current collector 30 hole H2 located in the center for injecting an electrolyte solution.

[0083] The housing coupling portion 33 may include a contact portion 33a coupled to the inner surface of the battery housing 20 and a connecting portion 33b connecting the support portion 31 to the contact portion 33a. In one aspect of the present disclosure, the joint coupling portion 32 may have a greater width than the connecting portion 33b. In another aspect of the present disclosure, the contact portion 33a may have a greater width than the connecting portion 33b.

[0084] The contact portion 33a is coupled to the inner surface of the battery case 20. Preferably, the contact portion 33a may be coupled to the crimping portion 21 of the battery case 20. In this case, for stable contact and coupling, both the crimping portion 21 and the contact portion 33a may extend in a direction substantially parallel to the lower surface of the battery case 20 (i.e., substantially perpendicular to the side wall of the battery case 20).

[0085] In another aspect of the present disclosure, the shell coupling portion 33 of the current collector 30 can be placed on the curling portion 21 and connected by welding in this state. In this case, the contact portion 33a of the shell coupling portion 33 can be connected to the curling portion 21. Through the above structure, the upper surface of the curling portion 21 can be physically covered by the contact portion 33a. However, the side of the curling portion 21 and the lower surface of the curling portion 21 cannot be physically protected by the contact portion 33a and are in a state vulnerable to flame damage. Therefore, more preferably, the heat-resistant coating C can extend downward from the starting point of the flat area on the upper surface of the curling portion 21.

[0086] In one aspect of the present disclosure, the heat-resistant coating C may include resin and ceramic particles.

[0087] In this case, the resin may include at least one of PI, PAI, silicone or epoxy. Meanwhile, the ceramic may include at least one of, for example, TiO2 or Al2O3. For example, the flame test confirmed that when the heat-resistant coating C includes TiO2, the time to generate the sidewall pores of the battery case 20 increases from 14.0 seconds to 38.8 seconds on average.

[0088] At the same time, it has been confirmed that when the heat-resistant coating C of the present disclosure includes silicone, chemical resistance is improved. In particular, it has been confirmed that chemical resistance is improved by changing the silicone coating component (increasing the amount of organic matter). However, the types of resins and ceramics included in the heat-resistant coating C of the present disclosure are not limited to the exemplary types. The type of resin and / or ceramic can be selected based on heat resistance, chemical resistance and electrolyte solution stability. That is, the heat-resistant coating C can be configured to meet a predetermined heat resistance requirement and a predetermined chemical resistance requirement.

[0089] In another aspect of the present disclosure, ceramics may be included, for example, in the form of particles. As an embodiment, the heat-resistant coating C may include ceramic particles in a resin base. That is, the heat-resistant coating C may include ceramic particles. In this case, the melting point of the ceramic particles may be, for example, above about 1000°C.

[0090] As described above, when the melting point of the ceramic particles included in the heat-resistant coating C is about 1000° C. or more, the risk of side cracking is significantly reduced. In addition, when the heat-resistant coating C includes ceramic particles in the resin base, the ceramic content can be easily adjusted. That is, the convenience of manufacturing can be improved.

[0091] In another aspect of the present disclosure, the heat-resistant coating C may include a first heat-resistant coating C coated on the battery case 20 and a second heat-resistant coating C coated on the first heat-resistant coating C.

[0092] That is, the heat-resistant coating C may include a plurality of coatings overlapping each other. In addition, the heat-resistant coating C may further include a third heat-resistant coating C. In addition, the heat-resistant coating C may further include a kth heat-resistant coating C. In this case, the types of the first heat-resistant coating C and the second heat-resistant coating C may be different.

[0093] Through the above structure, multiple coatings can improve heat resistance and chemical resistance. In addition, when multiple heat-resistant coatings C with different components are applied, the limitations of a single material in terms of heat resistance and chemical resistance can be overcome.

[0094] In another aspect of the present disclosure, the thickness of the heat-resistant coating C may be about 5 to 40 micrometers. Preferably, the thickness of the heat-resistant coating C may be about 15 to 30 micrometers.

[0095] For example, when the thickness of the heat-resistant coating C is less than about 5 microns, it is likely that the heat resistance performance cannot be ensured. On the contrary, when the thickness of the heat-resistant coating C is greater than about 40 microns, the coating is too thick and the internal space of the battery case 20 is too narrow. The volume of the electrode assembly 10 that can be accommodated in the battery cell 1 is reduced, and the final energy density is reduced. Therefore, the thickness of the heat-resistant coating C of the present disclosure is preferably about 5 microns to 40 microns, and the thickness is more preferably about 15 microns to 30 microns.

[0096] Figure 8 is a schematic diagram showing the shape of a heat-resistant coating C according to an embodiment of the present disclosure, and Fig. 9 is a schematic diagram showing the shape of a heat-resistant coating layer C according to another embodiment of the present disclosure. Fig.10 is a schematic diagram showing the shape of a heat-resistant coating layer C according to still another embodiment of the present disclosure.

[0097] Reference Figure 8 The heat-resistant coating C may be formed into a substantially strip shape having a constant width. That is, the heat-resistant coating C may be formed into a strip shape extending downward to a constant length L2 from a position at a predetermined distance D from an opening formed at one side of the battery case 20 in the height direction.

[0098] As another embodiment, the heat-resistant coating layer C may be formed in a partially coated shape in a region extending downward from a position a predetermined distance D from an opening portion formed at one side of the battery case 20 in the height direction.

[0099] For example, refer to Fig. 9 , the heat-resistant coating C may be formed into a substantially diagonal pattern. Fig.10, the heat-resistant coating C can be formed into a roughly grid pattern. As described above, the shape of the heat-resistant coating C is not limited to the strip shape, and the heat-resistant coating C can be formed into various shapes. Although not shown in the figure, the upper and lower edges of the heat-resistant coating C may have a curved shape. That is, the heat-resistant coating C can be arranged in the area reached by the flame generated in the battery housing 20, and can be applied in different shapes in some cases. For example, the heat-resistant coating C can be formed by covering the uncoated area with a masking tape and applying a coating agent. In this case, the shape of the heat-resistant coating C can vary according to the stamping shape of the masking tape. As described above, as long as the masking tape is applied to the inner wall of the battery housing 20, a heat-resistant coating C of different shapes (e.g., a horizontal shape, a vertical shape, a linear shape, or a curved shape) can be applied.

[0100] Through the above configuration, the material of the heat-resistant coating C can be reduced, and at the same time, the heat resistance of the heat-resistant coating C can be significantly improved.

[0101] Fig.11 is a schematic diagram showing damage to the battery case 20 caused by flame when a thermal event occurs in the battery cell 1 according to a comparative example of the present disclosure, and Fig.12 is a schematic diagram illustrating preventing damage to the battery case 20 caused by flame when a thermal event occurs in the battery cell 1 according to an embodiment of the present disclosure.

[0102] Reference Fig.11 When a thermal event occurs in the existing battery cell 1, the flame strongly contacts the lower surface and the side surface of the curling portion 21 due to the edge flow of the flame. As a result, the lower surface and / or the side surface of the curling portion 21 are broken, thereby generating a hole in the battery cell 1 or the side wall of the curling portion 21, causing the side surface to break or the flame to break out from the hole. In this case, not only the battery cell 1 where the thermal event occurs but also other battery cells 1 adjacent to the battery cell 1 are affected, causing the fire to spread.

[0103] In contrast, reference Fig.12 , since the heat-resistant coating C is applied to the battery cell 1 according to the embodiment of the present disclosure (more specifically, the heat-resistant coating C is applied to the curling portion 21), damage to the side of the battery cell 1 and / or the curling portion 21 can be effectively prevented. More specifically, referring to Fig.12 When the flame contacts the lower surface of the curling portion 21, the heat-resistant coating C can protect the lower surface of the curling portion 21, thereby effectively preventing the flame from causing damage to the curling portion 21 and / or the side of the battery cell 1. Therefore, the spread of fire can be prevented.

[0104] Fig.13 is a schematic diagram showing a battery pack 3 including a battery cell 1 according to an embodiment of the present disclosure.

[0105] Reference Fig.13 The battery pack 3 according to an embodiment of the present disclosure includes a battery assembly and a battery pack housing 2 accommodating the battery assembly, wherein the battery assembly includes a plurality of battery cells 1 electrically connected according to the embodiment of the present disclosure as described above. For ease of illustration, some components such as bus bars for electrical connection, cooling units, and power terminals are omitted.

[0106] Fig.14 It is shown that Fig.13 Schematic diagram of a vehicle 5 with a battery pack 3 .

[0107] Reference Fig.14 The vehicle 5 according to the embodiment of the present disclosure may include, for example, an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, and includes the battery pack 3 according to the embodiment of the present disclosure. The vehicle 5 includes a four-wheel vehicle and a two-wheel vehicle. According to the embodiment of the present disclosure, the vehicle 5 runs using the power supplied from the battery pack 3.

[0108] Although the present disclosure has been described above by means of a limited number of embodiments and drawings, the present disclosure is not limited thereto, and it will be apparent to those skilled in the art that various changes and modifications may be made to the present disclosure within the technical aspects of the present disclosure and the appended claims and their equivalents.

Claims

1. A battery cell, comprising: an electrode assembly, the electrode assembly comprising a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode; as well as a battery case, wherein the battery case accommodates the electrode assembly through an opening formed at one side, Wherein, at least a portion of the inner surface of the battery housing is coated with a heat-resistant coating.

2. The battery cell according to claim 1, wherein: The battery case includes a curling portion recessed inward from at least a portion of the one side.

3. The battery cell according to claim 2, wherein: The heat-resistant coating covers at least a portion of the curled edge portion.

4. The battery cell according to claim 2, wherein: The curling portion comprises: an upper surface located at a higher position than an innermost point of the recess; and A lower surface is located at a lower position than the innermost point of the recess.

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

6. The battery cell according to claim 1, wherein: The length of the covered area of ​​the heat-resistant coating in the winding axis direction has a width of 24% or more of the total length of the battery case before deformation.

7. The battery cell according to claim 2, wherein: The heat-resistant coating covers at least a portion of a region extending from an innermost point of the depression of the curling portion in a direction opposite to the opening portion.

8. The battery cell according to claim 2, wherein: The heat-resistant coating layer covers at least a portion of a region extending from a starting point of a flat region of an upper surface of the curled portion in a direction opposite to the opening.

9. The battery cell according to claim 1, wherein: The heat-resistant coating includes at least one of PI, PAI, silicone or epoxy.

10. The battery cell according to claim 1, wherein: The heat-resistant coating includes ceramic particles.

11. The battery cell according to claim 1, wherein: The heat-resistant coating includes at least one of TiO2 or Al2O3.

12. The battery cell according to claim 1, wherein: The heat-resistant coating comprises: A first heat-resistant coating layer, the first heat-resistant coating layer being coated on the battery housing; and A second heat-resistant coating layer is coated on the first heat-resistant coating layer.

13. The battery cell according to claim 1, wherein: The heat-resistant coating has a thickness of 5 micrometers to 40 micrometers.

14. A battery pack comprising at least one battery cell according to any one of claims 1 to 13.

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

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