Electrode assembly and secondary battery including the same

Abstract

The invention relates to an electrode assembly and a secondary battery including the same. An electrode assembly according to an embodiment of the present invention is formed by a positive electrode, a separator, and a negative electrode wound together, and may include a protective member disposed to face an end portion of at least one of the positive electrode and the negative electrode, and in which a flame retardant is filled.

Description

Technical Field

[0001] Cross - reference to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0125849, filed on September 30, 2022, which is hereby incorporated by reference in its entirety. Technical Field

[0004] The present invention relates to an electrode assembly and a device including the same, and more particularly, to an electrode assembly capable of improving safety and a secondary battery including the same. Background Art

[0005] Recently, as the demand for portable electronic products such as laptops, camcorders, and mobile phones has rapidly increased, and the development of electric vehicles, energy storage batteries, robots, satellites, etc. has been regularized, a lot of research has been conducted on secondary batteries used as driving power sources.

[0006] According to the shape of the battery case, rechargeable batteries are divided into coin type batteries, cylindrical type batteries, prismatic type batteries and pouch type batteries. The electrode assembly installed inside the battery case is a chargeable and dischargeable power generation device having a structure in which electrodes and separators are stacked.

[0007] When the charge / discharge cycle of a secondary battery including such an electrode assembly is repeated, expansion of the electrode assembly may occur and the winding center portion of the electrode assembly may be deformed. If the winding center portion of the electrode assembly is not maintained in its original shape and is deformed, an internal short circuit or disconnection may occur during the charge / discharge cycle, thereby significantly reducing safety. Summary of the invention

[0008] Technical issues

[0009] Embodiments of the present invention provide an electrode assembly capable of improving safety and a secondary battery including the electrode assembly.

[0010] The objects of the present invention are not limited to the above contents, but other objects not described herein will be clearly understood by those skilled in the art from the following description.

[0011] Technical Solution

[0012] The electrode assembly according to an embodiment of the present invention may be provided by winding a positive electrode, a separator, and a negative electrode, and includes a protection member arranged to face an end of at least one of the positive electrode or the negative electrode and filled with a flame retardant.

[0013] According to an embodiment, the protection member may be arranged to face an electrode having a relatively shorter length among the positive electrode and the negative electrode.

[0014] According to an embodiment, the protection member may be arranged on the separator to face a start end at which the positive electrode starts winding.

[0015] According to an embodiment, the negative electrode may include an extension region extending beyond the positive electrode in a direction opposite to a winding direction of the electrode assembly, and the protection member may overlap the extension region of the negative electrode.

[0016] According to an embodiment, the protective member may include: a first insulating layer, which is arranged on the separator and has a plurality of holes, in which a flame retardant is filled; a second insulating layer, which is arranged on the first insulating layer and is arranged to be oriented toward a winding center portion of the electrode assembly; and an adhesive layer, which is arranged between the first insulating layer and the second insulating layer.

[0017] According to an embodiment, a thickness of the second insulating layer may be less than a thickness of the first insulating layer and greater than or equal to a thickness of the adhesive layer.

[0018] According to an embodiment, the thickness of the first insulating layer may be 50% to 70% of the total thickness of the protective member, the thickness of the second insulating layer may be 20% to 30% of the total thickness of the protective member, and the thickness of the adhesive layer may be 10% to 20% of the total thickness of the protective member.

[0019] According to an embodiment, a melting temperature of the second insulating layer may be lower than a melting temperature of the first insulating layer.

[0020] According to an embodiment, the first insulating layer may include at least one of polyimide (PI) or polyethylene terephthalate (PET), and the second insulating layer may include any one of polyethylene (PE), polypropylene (PP), and polyurethane (PU).

[0021] According to an embodiment, the first insulating layer may include: a first insulating region; and a second insulating region arranged at each of two sides of the first insulating region, wherein the plurality of holes may be defined in the first insulating region but not in the second insulating region.

[0022] According to an embodiment, the flame retardant may include a flame retardant liquid containing fluorine.

[0023] According to an embodiment, the positive electrode may include: a positive electrode collector; a first active material layer arranged on an upper portion of the positive electrode collector; and a second active material layer arranged on a lower portion of the positive electrode collector, wherein the protective member may contact a starting end of at least one of the positive electrode collector, the first active material layer, or the second active material layer.

[0024] According to an embodiment, the electrode assembly may further include a negative electrode tab electrically connected to the negative electrode, wherein a width of the protection member may be less than or equal to a spacing distance between a start end of the positive electrode and the negative electrode tab.

[0025] According to an embodiment, the protection member may have the same thickness as that of the positive electrode.

[0026] According to an embodiment, the electrode assembly may further include a fire extinguishing agent filled in the protection member.

[0027] A secondary battery according to an embodiment of the present invention may include the above-mentioned electrode assembly.

[0028] Beneficial Effects

[0029] According to an embodiment of the present invention, the electrode assembly may include a protective member facing the winding start end of the positive electrode. The protective member may prevent cracks from occurring at a portion of the negative electrode in contact with the winding start end of the positive electrode to prevent disconnection or short circuit, thereby improving the safety of the secondary battery.

[0030] In addition, according to an embodiment of the present invention, the winding center portion of the electrode assembly can easily maintain the original shape of the winding center portion by the protective member. Therefore, internal short circuits can be prevented from occurring during the charge / discharge cycle of the secondary battery including the electrode assembly to ensure safety.

[0031] In addition, according to an embodiment of the present invention, a filling member containing a flame retardant may be filled into the protective member. The protective member containing such a flame retardant may prevent the temperature of the secondary battery from rising and causing ignition or explosion.

[0032] In addition, various effects directly or indirectly determined by the present disclosure can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a perspective view of a secondary battery including an electrode assembly according to a first embodiment of the present invention.

[0034] Figure 2 It's a picture. Figure 1 An exploded perspective view of an electrode assembly in an unfolded state before being wound.

[0035] Figure 3 It's a picture.Figure 1 A cross-sectional view of an unfolded state of an electrode assembly before being wound.

[0036] Figure 4 are a plan view and a cross-sectional view of a protective member according to the present invention.

[0037] Figure 5 It's a picture. Figure 2 An enlarged cross-sectional view of the periphery of the winding center portion after the electrode assembly is wound.

[0038] Figure 6 is a cross-sectional view illustrating an unfolded state of an electrode assembly before being wound according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0039] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. However, the present invention can be implemented in several different forms and is not limited or constrained by the following embodiments.

[0040] In order to explain the present invention clearly, the detailed description of the parts not related to the specification or the related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and in this specification, the reference numerals are added to the components in each figure. In this case, the same or similar reference numerals are assigned to the same or similar elements throughout the specification.

[0041] In addition, the terms or words used in the specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention based on the principle that the inventor can appropriately define the concepts of the terms in order to best describe and interpret his or her invention.

[0042] Secondary battery including an electrode assembly according to a first embodiment

[0043] Figure 1 is a perspective view of a secondary battery including an electrode assembly according to a first embodiment of the present invention, and Figure 2 It's a picture. Figure 1 An exploded perspective view of an electrode assembly in an unfolded state before being wound.

[0044] Reference Figures 1 to 2 , a secondary battery 10 according to an embodiment of the present invention may include an electrode assembly 100 and a battery case 180 .

[0045] The electrode assembly 100 may be accommodated in a battery case 180. The battery case 180 may include a battery can 182 and a cap assembly 181.

[0046] The battery can 182 may include a receiving portion 183 in which the electrode assembly 100 is received. The electrolyte may be injected into the receiving portion 183 so that the electrode assembly 100 is completely immersed in the battery can 182. The upper portion of the battery can 182 may be opened to serve as an inflow channel for the electrode assembly 100. The battery can 182 may include metal. For example, the battery can 182 may include stainless steel.

[0047] Since the battery can 182 accommodates the electrode assembly 100, the battery can 182 may be provided in a shape corresponding to the shape of the electrode assembly 100. For example, the battery can 182 may be provided in a cylindrical shape so as to accommodate the electrode assembly 100 provided in a wound shape.

[0048] The cap assembly 181 may be mounted on the battery can 182 to cover the opened upper portion of the battery can 182 and be coupled to the battery can 182. The cap assembly 181 may be provided by sequentially stacking a safety belt, a current blocking element, a positive temperature coefficient (PTC) element, and a top cover. The top cover is seated on the uppermost portion of the cap assembly 181 and is coupled to the uppermost portion of the cap assembly 181 to transmit the current generated in the secondary battery to the outside.

[0049] One of the battery can 182 and the cap assembly 181 may be electrically connected to the positive electrode tab 171 of the electrode assembly 100, and the other of the battery can 182 and the cap 181 may be electrically connected to the negative electrode tab 172 of the electrode assembly 100. For example, the cap assembly 181 may be electrically connected to the positive electrode tab 171 by a welding process, and the bottom surface of the battery can 182 may be electrically connected to the negative electrode tab 172 by a welding process. As another example, one of the battery can 182 and the cap assembly 181 may be electrically connected to the positive electrode tab 171 and the negative electrode tab 172.

[0050] The electrode assembly 100 may be a chargeable and dischargeable power generation element. The electrode assembly 100 has a structure in which the electrode 130 and the separator 160 are combined and alternately stacked. The electrode assembly 100 may be arranged in a shape in which the electrode 130 and the separator 160 are alternately combined to be wound. The electrode assembly 100 may have a structure in which its diameter is radially expanded in proportion to the number of winding rotations. Here, the electrode assembly 100 may be wound into a cylindrical shape wound around a winding center portion (or central axis) C. For example, the electrode 130 may include a positive electrode 110 and a negative electrode 120, and the separator 160 may include a first separator 140 and a second separator 150. The electrode assembly 100 may be an electrode assembly in a wound form, which is wound into a cylindrical shape by stacking the positive electrode 110, the first separator 140, the negative electrode 120 and the second separator 150 sequentially.

[0051] The positive electrode 110 may include: a positive electrode collector 113; a first positive electrode active material layer 111, the first positive electrode active material layer 111 is arranged on the outer surface (e.g., the surface facing the winding outer portion O) 123b of the positive electrode collector 113; and a second positive electrode active material layer 112, the second positive electrode active material layer 112 is arranged on the inner surface (e.g., the surface facing the winding center portion C) of the positive electrode collector 113. The positive electrode collector 113 may extend beyond at least one of the first positive electrode active material layer 111 or the second positive electrode active material layer 111 toward the winding outer portion O. A region on which at least one of the first positive electrode active material layer 111 or the second positive electrode active material layer 111 is not arranged but on which the positive electrode collector 113 is arranged may be a positive electrode uncoated portion 115. At least one positive electrode tab 171 may be fused to the positive electrode collector 113 of the positive electrode uncoated portion 115 by a method such as welding.

[0052] The positive electrode current collector 113 may be provided as a foil made of, for example, an aluminum material. At least one of the first positive electrode active material layer 111 or the second positive electrode active material layer may include, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound containing at least one of these and a mixture thereof.

[0053] The negative electrode 120 may include: a negative electrode collector 123; a first negative electrode active material layer 121, the first negative electrode active material layer 121 is arranged on the outer surface of the negative electrode collector 123 (for example, the surface facing the winding outer part O); and a second negative electrode active material layer 122, the second negative electrode active material layer 122 is arranged on the inner surface of the negative electrode collector 123 (for example, the surface facing the winding center part C). According to the formation positions of the first negative electrode active material layer 121 and the second negative electrode active material layer 122, the negative electrode 120 may be divided into a negative electrode coating portion 125 (or coating portion) and a negative electrode uncoated portion (or uncoated portion) 125. The negative electrode coating portion may be a region on which the first negative electrode active material layer 121 and the second negative electrode active material layer 122 are arranged. The negative electrode uncoated portion 125 may be a region on which at least one of the first negative electrode active material layer 121 or the second negative electrode active material layer 122 is not arranged. At least one negative electrode tab 172 may be fused to the negative electrode collector 123 of the negative electrode uncoated portion 125 by a method such as welding.

[0054] The negative electrode current collector 123 may be provided as a foil made of, for example, copper (Cu) or nickel (Ni) material. At least one of the first negative electrode active material layer 121 or the second negative electrode active material layer 122 may include, for example, synthetic graphite, lithium metal, lithium alloy, carbon, petroleum coke, activated carbon, graphite, silicon compound, tin compound, titanium compound or alloy thereof. At least one of the first negative electrode active material layer 121 or the second negative electrode active material layer 122 may include, for example, non-graphite SiO (silicon oxide) or SiC (silicon carbide).

[0055] The separator 160 may be arranged between the positive electrode 110 and the negative electrode 120 to separate and electrically insulate the positive electrode 110 from the negative electrode 120. The separator 160 may include a first separator 140 and a second separator 150. The first separator 140 may be stacked on the outside of the positive electrode 110 or the negative electrode 120. The second separator 150 may be stacked on the outside of the other of the positive electrode 110 and the negative electrode 120. For example, when the first separator 140 is stacked on the outside of the positive electrode 110, the first separator 140 may be arranged between the first positive active material layer 121 and the second negative active material layer 112. When the second separator 150 is stacked on the outside of the negative electrode 120, the second separator 150 may be arranged between the second positive active material layer 122 and the first negative active material layer 111. When a stack body in which the positive electrode 110 , the first separator 140 , the negative electrode 120 , and the second separator 150 are sequentially stacked is wound, a wound type electrode assembly 100 in which the second separator 150 is disposed on the outermost surface may be provided.

[0056] At least one of the first separator 140 or the second separator 150 may be, for example, a multilayer film made of polyethylene, polypropylene or a combination thereof, or a polymer film for a solid polymer electrolyte or a gel-type polymer electrolyte such as polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile or polyvinylidene fluoride hexafluoropropylene copolymer.

[0057] The electrode assembly 100 according to the present invention may include a protective member 200, which is arranged to face the end of at least one of the positive electrode 110 or the negative electrode 120. The protective member 200 may be arranged to face the start end of the shorter electrode of the positive electrode 110 and the negative electrode 120. The protective member 200 may be arranged closer to the winding center portion C than to the winding outer portion O. The protective member 200 may be arranged to be long along the width direction of the first separator 140 or the second separator 150. The protective member 200 may be arranged in parallel to at least one of the positive electrode tab 171 or the negative electrode tab 172.

[0058] Figure 3 It's a picture. Figure 2 A cross-sectional view of an electrode assembly in an unfolded state before being wound. Figure 3, the positive electrode 110, the first separator 140, the negative electrode 120, and the second separator 150 are illustrated as being spaced apart from each other, but the positive electrode 110, the first separator 140, the negative electrode 120, and the second separator 150 may be in close contact with each other after winding.

[0059] Reference Figure 3 , since the negative electrode 120 is arranged to surround the positive electrode 110 when wound, the negative electrode 120 may be configured to be longer than the positive electrode 110. The negative electrode 120 may include an extension region 126 extending beyond the positive electrode 110 in a direction opposite to the winding direction WD of the electrode assembly. The winding direction WD may refer to a direction in which the negative electrode 120 and the positive electrode 110 are wound. Figure 3 , the winding direction WD may be in a clockwise direction.

[0060] The protective member 200 may overlap the extension region 126 of the negative electrode 120 and may be arranged to face the winding start end AE of the positive electrode 110. The protective member 200 may be arranged on the first separator 140 and in contact with the winding start end AE of the positive electrode 110. The protective member 200 may be in contact with the winding start end AE of at least one of the first positive active material layer 111, the second positive active material layer 112, or the positive current collector 113.

[0061] The protective member 200 may be disposed on one surface of the first separator 140 facing the winding center portion C. The protective member 200 may have a thickness T corresponding to the thickness of the positive electrode 110. The thickness T of the protective member 200 may be the same as the thickness of the positive electrode 110. For example, the thickness of the protective member 200 may be 90 μm to 150 μm, and in the present invention, the thickness of the protective member 200 is not limited. Since the thickness of the positive electrode 110 may vary according to the product characteristics of the electrode assembly, the thickness of the protective member may be set to be the same as the thickness of the positive electrode according to the product characteristics.

[0062] The protective member 200 may be arranged to be wound from the winding start end AE of the positive electrode 110 toward the winding center portion C. The protective member 200 may extend from the winding start end AE of the positive electrode 110 toward the winding center portion C. As an example, the protective member 200 may be arranged between the winding start end AE of the positive electrode 110 and the winding start end CE of the negative electrode 120. As another example, the protective member 200 may be arranged between the winding start end AE of the positive electrode 110 and the negative electrode tab 172. The width W of the protective member 200 may be less than or equal to the distance D from the winding start end AE of the positive electrode to the negative electrode tab 172. For example, the width W of the protective member 200 may be 10 mm to 21 mm. The protective tab 173 may be attached to the negative electrode tab 172 or the positive electrode tab (e.g., Figure 1The protective tab 173 may relieve the step portion provided by the electrode tabs 171 and 172 to prevent the separators 140, 150 facing the electrode tabs 171, 172 from being damaged.

[0063] The protective member 200 may cover the step portion of the winding start end AE of the positive electrode 110. The protective member 200 may remove the step portion of the winding start end AE corresponding to the maximum thickness of the positive electrode 110. The negative electrode 120 that shrinks and expands when charging and discharging of the secondary battery is performed is not bent to the winding start end AE of the positive electrode 110 by the protective member 200. The winding start end AE of the positive electrode can be prevented from contacting the negative electrode. Therefore, since cracks of the first separator 140 are prevented from occurring through the winding start end AE of the positive electrode 110, an electrical short circuit between the negative electrode 120 and the positive electrode 110 can be prevented.

[0064] In addition, the winding center portion C of the electrode assembly may be easily maintained in a circular shape by the protection member 200. Therefore, an internal short circuit may be prevented from occurring during a charge / discharge cycle of a secondary battery including the electrode assembly to ensure safety.

[0065] Figure 4 are a plan view and a cross-sectional view of a protective member according to the present invention, and Figure 5 It's a picture. Figure 2 FIG. 1 is an enlarged cross-sectional view of the periphery of the winding center portion C after the electrode assembly is wound.

[0066] Reference Figure 4 and Figure 5 The protective member 200 may be provided in the form of an insulating tape. The protective member 200 may include a first insulating layer 301, an adhesive layer 201, and a second insulating layer 302 sequentially stacked on one surface of the first separator 140.

[0067] The adhesive layer 201 may be disposed between the first insulating layer 301 and the second insulating layer 302 to allow the first insulating layer 301 and the second insulating layer 302 to adhere to each other. In addition, the protective member 200 may be attached to the first separator 140 by the second adhesive layer 202. The second adhesive layer 202 may be disposed between the first insulating layer 301 and the first separator 140.

[0068] The first insulating layer 301 may include a first insulating region 310 and a second insulating region 320 .

[0069] The first insulating region 310 may include a first surface 311, a second surface 312, and a third surface 313. The first surface 311 may be arranged to face the winding center portion C (or the second insulating layer 302). The second surface 312 may be arranged to face the direction opposite to the first surface 311 (or toward the second adhesive layer 202 or the first separator 140). The third surface 313 may be provided in plurality between the first surface 311 and the second surface 312. The plurality of third surfaces 313 may be arranged to intersect the first surface 311 and the second surface 312.

[0070] The first insulating region 310 may include a plurality of holes 330. The first filling member 340 may be filled into the plurality of holes 330. For example, the first filling member 340 may be a flame retardant liquid (or flame retardant) containing fluorine (F). Figure 1 When the secondary battery 10 in the embodiment of the present invention is in an abnormal operation state such as an overcurrent state or a high temperature state, the first filling member 340 in a liquid state may flow out from the protective member 200. The first filling member 340 may flow out to the winding center portion C in the abnormal operation state of the secondary battery 10 to cool the electrode assembly. The first filling member 340 may prevent the temperature of the secondary battery from rising and causing ignition or explosion.

[0071] The second insulating region 320 may be arranged to surround a portion of the first insulating region 310. As an example, the second insulating region 320 may be arranged to surround the plurality of third surfaces 313 of the first insulating region 310 but not the first surface 311 and the second surface 312. As another example, the second insulating region 320 may be arranged to surround the second surface 312 and the plurality of third surfaces 313 of the first insulating region 310 but not the first surface 311. The second insulating region 320 may be used to confine the first filling member 340 within the first insulating region 310 to prevent the first filling member 340 in a liquid state from flowing out during normal operation of the secondary battery.

[0072] The first insulating region 310 and the second insulating region 320 may be made of different materials, or may be integrally formed with the same material. At least one of the first insulating region 310 or the second insulating region 320 may be made of an electrically insulating plastic material. Each of the first insulating region 310 and the second insulating region 320 may be made of a material having a higher melting point than that of the second insulating layer 302 and not easily melted at high temperatures. For example, the first insulating layer 301 including the first insulating region 310 and the second insulating region 320 may include at least one of polyimide (PI) or polyethylene terephthalate (PET).

[0073] The second insulating layer 302 may be disposed on the adhesive layer 201 to face the winding center portion C. The second insulating layer 302 may be disposed closer to the winding center portion C than at least one of the adhesive layer 201 or the first insulating layer 301.

[0074] The second insulating layer 302 and the adhesive layer 201 may be configured to be easily melted at high temperatures. For example, the second insulating layer 302 and the adhesive layer 201 may be configured to melt when the internal temperature of the secondary battery exceeds 100 degrees Celsius. When the second insulating layer 302 and the adhesive layer 201 are melted at high temperatures, the flame retardant 340 inside the first insulating layer 301 may flow out from the protective member 200. The second insulating layer 302 may be made of a material having a melting point lower than that of the first insulating layer 301. For example, the second insulating layer 302 may include any one of polyethylene (PE), polypropylene (PP), and polyurethane (PU).

[0075] The first insulating layer 301 provided in the protective member 200 may be provided to be thicker than the thicknesses of each of the adhesive layer 201 and the second insulating layer 302. The second insulating layer 302 may be provided to have a thickness equal to or greater than the thickness of the adhesive layer 201. The thickness T301 of the first insulating layer 301 may account for 50% to 70% of the total thickness of the protective member 200. The thickness T302 of the second insulating layer 302 may account for 20% to 30% of the total thickness of the protective member 200. The thickness T201 of the adhesive layer 201 may account for 10% to 20% of the total thickness of the protective member 200. Since the first insulating layer 301 is provided to be thicker than each of the adhesive layer 201 and the second insulating layer 302, the proportion of the first filling member 340 filled in the first insulating layer 301 in the protective member 200 may be increased. Therefore, the protective member including the first filling member 340 can prevent ignition or explosion caused by an increase in the temperature of the secondary battery.

[0076] Electrode assembly according to a second embodiment

[0077] Figure 6 is a cross-sectional view showing an unfolded state before the electrode assembly according to the second embodiment of the present invention is wound.

[0078] The electrode assembly according to the second embodiment of the present invention may be the same as Figures 1 to 5 the illustrated electrode assembly according to the first embodiment of the present invention, except that the first filling member 340 and the second filling member 600 are filled in the plurality of holes 330. Therefore, a detailed description of the same components will be cited from Figures 1 to 5 the description.

[0079] Refer to Figure 6, the protective member 200 may include a plurality of holes 330. Some of the plurality of holes 330 may be filled with a first filling member 340. Other holes of the plurality of holes 330 may be filled with a second filling member 600. The first filling member 340 and the second filling member 600 may be made of different materials. The first filling member 340 may include a flame retardant liquid. As an example, the second filling member 600 may include a fire extinguishing agent 610. As another example, the second filling member 600 may be arranged in a form in which a shell 620 surrounds a core containing the fire extinguishing agent 610. Since the shell 620 melts when the secondary battery is ignited, the fire extinguishing agent 610 contained in the core may be discharged toward the winding center portion C. The fire extinguishing agent 610 contained in the second filling member 600 may not chemically react with the flame retardant contained in the first filling member 340.

[0080] The fire extinguishing agent 610 may be discharged toward the winding center C when the secondary battery is ignited to extinguish the fire in a short time and prevent the fire of the ignited electrode assembly 100 from spreading to the adjacent electrode assembly 100 .

[0081] The secondary battery including the electrode assembly described above can be applied to various devices. The secondary battery including the electrode assembly described above can be applied to vehicles such as electric bicycles, electric vehicles, hybrid vehicles, etc., but is not limited thereto, and can be applied to various devices that can use the battery module.

[0082] While embodiments of the present invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.

[0083] [Description of Reference Signs]

[0084] 100: Electrode assembly

[0085] 110: First electrode

[0086] 120: Second electrode

[0087] 140: First separator

[0088] 150: Second separator

[0089] 171, 172: Electrode tabs

[0090] 200: Protective components

[0091] 340, 600: Filling components

Claims

1. An electrode assembly, in which a positive electrode, a separator and a negative electrode are wound, and the electrode assembly include: A protection member is arranged to face an end of at least one of the positive electrode or the negative electrode and a flame retardant is filled in the protection member.

2. The electrode assembly according to claim 1, in, The protection member is arranged to face an electrode having a relatively shorter length among the positive electrode and the negative electrode.

3. The electrode assembly according to claim 1, in, The protection member is arranged on the separator so as to face a start end at which the positive electrode starts to be wound.

4. The electrode assembly according to claim 1, in, The negative electrode includes an extension region extending beyond the positive electrode in a direction opposite to a winding direction of the electrode assembly, and The protection member overlaps the extension region of the negative electrode.

5. The electrode assembly according to claim 1, in, The protection member comprises: a first insulating layer, the first insulating layer being arranged on the separator and having a plurality of holes, the flame retardant being filled in the plurality of holes; a second insulating layer disposed on the first insulating layer and arranged to be oriented toward a winding center portion of the electrode assembly; and An adhesive layer is disposed between the first insulating layer and the second insulating layer.

6. The electrode assembly according to claim 5, in, The thickness of the second insulating layer is smaller than that of the first insulating layer and greater than or equal to that of the adhesive layer.

7. The electrode assembly according to claim 5, in, The thickness of the first insulating layer is 50% to 70% of the total thickness of the protection member. The thickness of the second insulating layer is 20% to 30% of the total thickness of the protection member, and The thickness of the adhesive layer is 10% to 20% of the total thickness of the protection member.

8. The electrode assembly according to claim 5, in, The melting temperature of the second insulating layer is lower than the melting temperature of the first insulating layer.

9. The electrode assembly according to claim 5, in, The first insulating layer includes at least one of polyimide (PI) or polyethylene terephthalate (PET), and The second insulating layer includes any one of polyethylene (PE), polypropylene (PP), and polyurethane (PU).

10. The electrode assembly according to claim 5, in, The first insulating layer comprises: a first insulating region; and a second insulating region, the second insulating region being arranged at each of the two sides of the first insulating region, The plurality of holes are defined in the first insulating region but not in the second insulating region.

11. The electrode assembly according to claim 1, in, The flame retardant includes a flame retardant liquid containing fluorine.

12. The electrode assembly according to claim 1, in, The positive electrode comprises: positive electrode current collector; a first active material layer disposed on an upper portion of the positive electrode current collector; and a second active material layer disposed on a lower portion of the positive electrode current collector, The protective member is in contact with a starting end of at least one of the positive electrode current collector, the first active material layer, or the second active material layer.

13. The electrode assembly according to claim 1, further comprising a negative electrode tab electrically connected to the negative electrode, in, The width of the protection member is less than or equal to a spacing distance between a starting end of the positive electrode and the negative electrode tab.

14. The electrode assembly according to claim 1, in, The protection member has the same thickness as that of the positive electrode. 15 . The electrode assembly according to claim 1 , further comprising a fire extinguishing agent filled in the protection member. 16 . A secondary battery comprising the electrode assembly according to claim 1 .

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