Electrode assembly for secondary battery and cylindrical secondary battery including the same

Abstract

The present invention relates to an electrode assembly for a secondary battery, which is formed by winding up an electrode laminate including: a positive electrode including a positive electrode current collector and a positive electrode active material layer formed on at least one surface of the positive electrode current collector; a negative electrode including a negative electrode current collector and a negative electrode active material layer formed on at least one surface of the negative electrode current collector; and a separator interposed between the positive electrode and the negative electrode, wherein one end of the negative electrode in the longitudinal direction toward the center of the winding is a negative electrode uncoated portion where no negative electrode active material layer is formed; and the positive electrode is provided with a ceramic-containing film member at one end of the positive electrode in the longitudinal direction toward the center of the winding.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0141905, filed October 28, 2022, and Korean Patent Application No. 10-2023-0141161, filed October 20, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to an electrode assembly for a secondary battery that can prevent an internal short circuit caused by damage to a separator, and a cylindrical secondary battery including the same. [Background technology]

[0003] Depending on the shape of the battery case, secondary batteries are classified into cylindrical batteries and prismatic batteries, in which the electrode assembly is housed in a cylindrical or prismatic metal can, and pouch batteries, in which the electrode assembly is housed in a pouch-shaped case made of an aluminum laminate sheet.

[0004] The electrode assembly housed in the battery case is a chargeable and dischargeable power generating element having a laminated structure of a positive electrode / separator / negative electrode, and can be classified into a jelly roll structure in which a separator is interposed between long sheet-like positive and negative electrodes coated with an active material and wound up, a stack structure in which a number of positive and negative electrodes of a predetermined size are stacked in order with a separator interposed therebetween, and a stack / folding type electrode assembly having a structure in which a bicell or full cell in which a predetermined number of positive and negative electrodes are stacked with a separator interposed therebetween is wound up.

[0005] Among these, jelly-roll type electrode assemblies are widely produced due to their advantages of being easy to manufacture and having a high energy density per weight. A jelly-roll type electrode assembly can be manufactured by assembling a laminate of long sheet-shaped positive and negative electrodes with a separator interposed therebetween, and winding the laminate in the length direction of the sheet with one end of the electrode laminate in contact with a winding core.

[0006] Specifically, as shown in FIG. 6, separators 1a and 1b are first inserted onto the core and fixed in an overlapping state. Then, as the core rotates, negative electrode 2 is inserted, followed by positive electrode 3 after a time lag. Once positive electrode 3 is inserted, the core rotates a predetermined number of times to form a jelly roll, as shown in FIG. 7. That is, separators 1a and 1b, negative electrode 2, and positive electrode 3 are positioned outward from the center of the jelly roll. Although FIG. 7 shows internal spaces between the negative electrode, separator, and positive electrode as they rotate, this is intentionally shown as spaced apart for clarity; in reality, the negative electrode, separator, and positive electrode come into close contact with each other during rotation and are wound into a solid cylindrical shape.

[0007] Meanwhile, electrodes may be deformed due to repeated expansion and contraction during battery charging and discharging. In particular, since jelly-roll-type electrode assemblies have a densely packed shape, such deformation can cause an increase in the internal temperature. If the electrodes are deformed or the internal temperature increases excessively, the separator in the electrode assembly may be damaged, which may lead to a short circuit between the positive and negative electrodes. This can further increase the internal temperature of the electrode assembly, potentially causing serious safety issues such as fire or explosion. Therefore, a solution to this safety issue is needed. Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE INVENTION An object of the present invention is to provide an electrode assembly for a secondary battery and a cylindrical secondary battery that eliminate the above-mentioned safety problems by introducing a ceramic-containing film member. [Means for solving the problem]

[0009] The present invention relates to a battery comprising a positive electrode including a positive electrode current collector and a positive electrode active material layer formed on at least one surface of the positive electrode current collector; a negative electrode including a negative electrode current collector and a negative electrode active material layer formed on at least one surface of the negative electrode current collector; an electrode assembly in a wound electrode stack including the positive electrode and the negative electrode; and a separator interposed between the positive electrode and the negative electrode, one end of the negative electrode in the longitudinal direction toward the center of the winding is a negative electrode uncoated portion on which no negative electrode active material layer is formed, The positive electrode has a ceramic-containing film member at one end of the positive electrode that faces the center of the winding, among both ends in the length direction, to provide an electrode assembly for a secondary battery.

[0010] The present invention also provides a secondary battery electrode assembly, a battery can in which the electrode assembly is housed; and a cap assembly for sealing the open end of the battery can. [Effects of the Invention]

[0011] When a cylindrical secondary battery is manufactured using the electrode assembly for a secondary battery according to the present invention, deformation of the electrodes during charging and discharging and resulting damage to the separator can be prevented, ultimately reducing the risk of an internal short circuit, thereby improving the safety of the secondary battery. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram illustrating an electrode stack according to one embodiment of the present invention. [Figure 2] 1 is a diagram showing a comparison of the state of the center of winding in a jelly roll-type electrode assembly when a ceramic-containing film member is not introduced (left side) and when it is introduced (right side). [Figure 3] 1 is a diagrammatic view of a ceramic-containing film member according to one embodiment of the present invention. [Figure 4] 4A to 4C are diagrams showing various shapes that the AA' cross section of the ceramic-containing film member shown in FIG. 3 may have. [Figure 5]FIG. 10 is a graph showing the results of measuring the voltage change over time of the secondary batteries manufactured in the examples and comparative examples. [Figure 6] 1 is a diagram illustrating a process in which a separator, a negative electrode, and a positive electrode are placed on a core when manufacturing a jelly roll-type electrode assembly by a conventional method. [Figure 7] 7A to 7C are diagrams showing the process of forming a jelly roll as the core rotates in the state shown in FIG. 6. [Figure 8] 1 is a vertical cross-sectional perspective view of a cylindrical secondary battery according to one embodiment of the present invention. [Figure 9] 1A and 1B are diagrams illustrating the structure of a cap assembly according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily understand the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0014] In the drawings, parts that are not related to the description of the present invention will be omitted.

[0015] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary and dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that an inventor can appropriately define the concept of a term in order to best explain his or her invention.

[0016] As mentioned above, repeated expansion and contraction during charging and discharging of a secondary battery can deform the electrodes and damage the separator, resulting in a short circuit between the positive and negative electrodes. In cylindrical secondary batteries, pressure is concentrated at the center of the winding, which can make this problem more frequent. In particular, if the positive electrode is a free edge positive electrode that does not include a non-coating portion, this problem becomes more severe due to the large thickness difference.

[0017] Therefore, the inventors discovered that by introducing a ceramic-containing film member into the end portion of each longitudinal end of the positive electrode that faces the center of the winding, it is possible to prevent deformation of the electrode and reduce thickness differences, thereby solving the problems of separator damage and internal short circuits that occur at the center of the winding of the electrode assembly.

[0018] Each of the components of the present invention will be described in more detail below.

[0019] [Electrode assembly] The electrode assembly for a secondary battery according to the present invention is in the form of a wound electrode laminate including: a positive electrode including a positive electrode current collector and a positive electrode active material layer formed on at least one surface of the positive electrode current collector; a negative electrode including a negative electrode including a negative electrode active material layer formed on at least one surface of the negative electrode current collector; and a separator interposed between the positive electrode and the negative electrode; and the negative electrode has a structure in which one of both longitudinal end portions of the negative electrode facing the center of the winding is a negative electrode uncoated portion where no negative electrode active material layer is formed, and the positive electrode has a ceramic-containing film member at one of both longitudinal end portions facing the center of the winding.

[0020] As shown in FIG. 1, the electrode laminate may have a structure in which a separator 1b, a positive electrode 3 having a positive electrode active material layer 3a provided on both sides of a positive electrode current collector 3b, a separator 1a, and a negative electrode 2 having a negative electrode active material layer 2a provided on both sides of a negative electrode current collector 2b are laminated in this order.

[0021] Meanwhile, the ceramic-containing film member may be provided in an area that coincides with or is wider than the negative electrode uncoated region across the separator. That is, the area 31a where the ceramic-containing film member is provided preferably coincides with or is wider than the negative electrode uncoated region 21a across the separator 1a. Referring to FIG. 1, it can be seen that the ceramic-containing film member 31 attached to the end of the positive electrode 3 is formed wider (longer in the drawing) so as to completely cover the negative electrode uncoated region 21a located at the end of the negative electrode 2 that is to become the winding center C.

[0022] Preferably, the ceramic-containing film member is provided on both sides of the positive electrode.

[0023] In one embodiment of the present invention, the ceramic-containing film member is a polymer film having a melting point of 130°C or higher to which ceramic is added. As a preferred example, ceramic 51 may be contained in a polymer film 50 in the form of stripes at regular intervals, as shown in Figure 3. Figure 4 is a schematic diagram showing a cross section of part A-A' in Figure 3, in which the polymer film and ceramic may be alternately attached as shown in (a), ceramic 51 may be substituted for part of the polymer film as shown in (b), or ceramic 51 may be attached or coated on one or both sides of polymer film 50 as shown in (c) and (d).

[0024] The ceramic-incorporated film has higher physical rigidity and fixing strength than conventional polymer films due to the high strength properties of ceramics, and can more effectively suppress changes in electrode length during charge and discharge, thereby preventing damage to the separator due to electrode deformation. Specifically, the ceramic-containing film member may have a tensile strength of 200 N / cm to 400 N / cm, preferably 250 N / cm to 350 N / cm, and more preferably 280 N / cm to 320 N / cm.

[0025] In one embodiment of the present invention, the ceramic-containing film member is a polymer film containing ceramic in stripes at regular intervals, and the width of one row of the ceramic (w in FIG. 4) may be 1 mm to 3 mm, and the spacing between the stripes (y in FIG. 4) may be 7 mm to 10 mm.

[0026] On the other hand, the area of ​​the ceramic-containing film member on the surface that contacts the separator can be 5% or more of the total area of ​​the ceramic-containing film member, but considering flexibility during winding, it is preferably 10% or less. The thickness of the ceramic-containing film member can be 20 μm or more and 170 μm or less, preferably 150 μm or less, more preferably 50 μm or less. It is preferable that the thickness of the ceramic-containing film member is in the above range because the effects of the present invention can be achieved without reducing the energy density.

[0027] The polymer may be at least one selected from the group consisting of polyimide, polypropylene, polyethylene terephthalate, polystyrene, polycarbonate, and polysulfone, and is preferably at least one selected from the group consisting of polyimide, polypropylene, and polyethylene terephthalate. In particular, the ceramic-containing film member may be a polymer tape having ceramic introduced thereinto in stripes, as described above.

[0028] The ceramic is at least one selected from the group consisting of glass fiber, tungsten carbide (WC), Al2O3, Cr2O3, SiO2, MnO, ZnO, SnO, PbO, TiO2, B4C, TiC, SiC, AlN, Si3N4, MgB2, TiB2, TiAl, NiTi, and Al2Si2O5(OH)4. In consideration of electrical stability and strength, glass fiber, Al2O 3、and SiC, and glass fiber is most preferred.

[0029] Meanwhile, the positive electrode, negative electrode, and separator can be any electrode that is commonly used in secondary batteries, and the following description may be referred to for preferred examples.

[0030] The positive electrode 3 is a sheet-shaped positive electrode and can include a positive electrode current collector 3b made of a thin metal plate with excellent conductivity, such as aluminum foil, and a positive electrode active material layer 3a coated on both sides thereof. The negative electrode 2 is a sheet-shaped negative electrode and can include a negative electrode current collector 2b made of a thin metal plate with excellent conductivity, such as copper (Cu) or nickel (Ni) foil, and a negative electrode active material layer 2a coated on both sides thereof.

[0031] The positive electrode active material layer may include a lithium metal oxide containing lithium and a transition metal such as cobalt, manganese, and / or nickel as a positive electrode active material, and may further include a conductive material and / or a binder, as necessary. The positive electrode active material, conductive material, and binder may be any of various materials commonly used in the manufacture of secondary batteries, without limitation.

[0032] Meanwhile, at the longitudinal end of the positive electrode toward the winding center, the end of the positive electrode active material layer and the end of the positive electrode current collector may coincide. That is, the longitudinal end of the positive electrode toward the winding center does not have a positive electrode uncoated portion. More specifically, both longitudinal end portions may be free edge positive electrodes that do not include a positive electrode uncoated portion. In this case, the positive electrode uncoated portion refers to a region of the positive electrode where the positive electrode active material layer is not formed.

[0033] When a positive electrode includes a positive electrode uncoated portion, active material slurry scattered during the formation of the positive electrode active material layer may adhere to the uncoated portion, forming an island-like positive electrode active material layer. This may cause an internal short circuit when the electrode laminate contracts and expands during the charge and discharge process of the battery.

[0034] To prevent this, it is preferable to introduce a free-edge positive electrode. However, as mentioned above, when an electrode stack including a free-edge positive electrode is wound, the thickness difference makes it more likely that the separator will be damaged and an internal short circuit will occur at the center of the winding.

[0035] Therefore, in such a free edge positive electrode, the need for the ceramic-containing film member of the present invention is even greater, and the effect of applying the ceramic-containing film member can be further maximized.

[0036] The negative electrode active material layer may include a negative electrode active material such as a carbonaceous material, such as natural graphite or artificial graphite; a metal or an alloy of the metal; an oxide of the metal; or a composite of the metal and carbon, and may further include a conductive material and / or a binder, as necessary. The negative electrode active material, conductive material, and binder may be any of various materials commonly used in the manufacture of secondary batteries, without limitation.

[0037] The separators 1a and 1b included in the electrode laminate may be conventional porous polymer films, such as polyolefin porous polymer films made of ethylene homopolymer, propylene homopolymer, ethylene-butene copolymer, ethylene-hexene copolymer, or ethylene-methacrylate copolymer, either alone or in combination. Alternatively, polyolefin porous polymer films coated with inorganic particles (e.g., Al2O3) or conventional porous nonwoven fabrics, such as nonwoven fabrics made of high-melting-point glass fibers or polyethylene terephthalate fibers, may be used, but are not limited thereto.

[0038] Meanwhile, in an electrode assembly according to an embodiment of the present invention, an electrode laminate is wound in the R direction as shown in Fig. 1, and after winding, portion C may form the winding center. The electrode assembly wound in this manner may be in the form of, for example, a jelly roll.

[0039] The center of the winding of the electrode assembly is shown diagrammatically in Figure 2. The left-hand diagram shows a conventional electrode assembly in which a ceramic-containing film member is not formed at the end of the positive electrode 3. In this case, if the negative electrode uncoated portion 21 is deformed due to stress applied to the electrode during charging and discharging, the separator 1a may also be damaged, potentially causing a short circuit between the positive electrode 3 and the negative electrode uncoated portion 21.

[0040] In contrast, when a ceramic-containing film member 31 is attached to the end of the positive electrode 3 as shown in the right-hand figure, it has the effect of fixing the positive electrode 3, making it possible to withstand the stress applied to the electrode during the charge / discharge process and also preventing deformation of the negative electrode uncoated portion 21.

[0041] Meanwhile, the ceramic-containing film member may have ceramic introduced in stripes horizontally in the winding direction of the electrode stack. Referring to Figure 3, the ceramic-containing film member may be arranged so that part C is located at the center of the winding and part E is located at the end of the winding. This is advantageous in terms of having the strength to withstand stress acting in the winding direction.

[0042] [Cylindrical secondary battery] A cylindrical secondary battery according to the present invention includes the electrode assembly, a battery can in which the electrode assembly is housed, and a cap assembly that seals the open end of the battery can. Specifically, the cylindrical secondary battery 100 shown in Fig. 8 can be manufactured by housing a jelly-roll-type electrode assembly 120 in a battery can 130, injecting an electrolyte into the battery can 130, and then attaching and sealing a cap assembly 140 to the open top of the battery can 130. In this case, the cap assembly 140 is electrically connected to the electrode assembly 120 via an electrode tab (e.g., a positive electrode tab) extending from the electrode assembly 120.

[0043] As described above, the electrode assembly 120 has a structure in which the positive electrode 3, the negative electrode 2, and the separator 1 interposed between them are wound into a round shape, and a circular center pin 150 is inserted into the winding core (the center of the jelly roll). The center pin 150 is generally made of a metal material to provide a predetermined strength, and has a hollow circular structure made by bending a plate material into a round shape. The center pin 150 functions to fix and support the electrode assembly and also acts as a passage for releasing gas generated by internal reactions during charge / discharge and operation.

[0044] Referring to FIG. 9 , which illustrates the typical structure of the cap assembly 140, the top cap 10 protrudes to form the positive electrode terminal, has an exhaust port (not shown) perforated therein, and has a safety vent 20 positioned at the bottom of the top cap. A portion of the top surface of the CID filter 30 is connected to the safety vent 20, and a portion of the bottom surface is connected to the electrode of the electrode assembly 120. When gas is generated from the electrode assembly 120 due to overcharging, high temperature, or other reasons, and the internal pressure increases, the safety vent 20 reverses its shape and protrudes upward, allowing the gas to be exhausted. At this time, the CID filter 30 also moves upward, rupturing the area of ​​the notch T and cutting off the current flow. This prevents further overcharging and battery explosion.

[0045] The cap assembly also includes an insulating gasket 32 ​​that provides airtightness between the top cap 10 and the battery can 130. The top cap 10 may be crimped onto a bead portion 60 formed on the battery can 130 and secured by a crimping portion 70. The top cap 10 is a component made of a conductive metal material and covers the top opening of the battery can 130. The top cap 10 is electrically connected to the positive electrode of the electrode assembly 120 and is electrically insulated from the battery can 130 by the gasket 32. Therefore, the top cap 10 can function as a positive electrode terminal of the cylindrical secondary battery. The top cap 10 has a protrusion formed at its center that protrudes upward, and the protrusion may be in contact with an external power source to apply current from the external power source.

[0046] Meanwhile, the electrolyte may be any solution that allows the movement of lithium ions generated by an electrochemical reaction at the electrodes during charging and discharging, and may be, for example, a non-aqueous organic solvent in which a lithium salt is dissolved.

[0047] The lithium salt can be any compound capable of providing the lithium ions used in lithium secondary batteries, without particular limitations. Specifically, examples of the lithium salt include LiPF, LiClO, LiAsF, LiBF, LiSBF, LiAlO, LiAlCl, LiCF, SO, LiCF, SO, LiN(C, F, SO), LiN(C, F, SO), LiN(CF, SO), LiCl, LiI, and LiB(C, O) . The concentration of the lithium salt can be varied within a range typically used, but is generally within the range of 0.1 to 5.0 M, preferably 0.1 to 3.0 M.

[0048] The non-aqueous organic solvent may be any solvent that can act as a medium for the movement of ions involved in the electrochemical reaction of the battery, including, for example, cyclic carbonate solvents such as ethylene carbonate (EC), propylene carbonate (PC), and vinylene carbonate, linear carbonate solvents such as dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, and ethyl methyl carbonate (EMC), and mixtures thereof.

[0049] The cylindrical secondary battery can be applied to various devices, for example, electric vehicles such as electric bicycles, electric vehicles, and hybrid electric vehicles (HEVs).

[0050] Therefore, according to another embodiment of the present invention, there is provided a battery module including the cylindrical secondary battery as a unit cell, and a battery pack including the same.

[0051] The battery module or battery pack can be used as a power source for one or more medium- to large-sized devices, such as power tools; electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); or power storage systems.

[0052] The present invention will be described in more detail below with reference to specific examples. [Mode for Carrying Out the Invention]

[0053] <Example: Manufacturing of Cylindrical Secondary Battery> Example 1 Li[Ni 0.60 Co 0.20 Mn 0.20A lithium nickel cobalt manganese oxide having a composition of 02, a carbon black conductive material, and a PVDF binder were mixed in N-methylpyrrolidone at a weight ratio of 95:2:3 to prepare a positive electrode slurry. The positive electrode slurry was applied to one side of an aluminum current collector, dried, and then roll-pressed to prepare a positive electrode.

[0054] Graphite, SBR-CMC binder, and carbon black conductive material were mixed in a weight ratio of 95:3.5:1.5 with water as a solvent to prepare anode slurry. The anode slurry was applied to a copper foil as an anode current collector, dried, and then roll-pressed to prepare an anode.

[0055] Next, a ceramic filament tape (3M Scotch Filament Tape 8915) made of polypropylene fabric containing glass fiber was attached to the end of the positive electrode that was to become the center of winding, as shown in Figure 1. At this time, the area where the ceramic filament tape 31 was attached was set to cover the entire area corresponding to the negative electrode uncoated portion 21 located at the center of winding.

[0056] Then, a sheet-shaped polyethylene separator 1b, the positive electrode 3 with the ceramic filament tape 31 attached, the polyethylene separator 1a, and the negative electrode 2 were stacked in this order and then wound up together in the R direction to manufacture a jelly roll-shaped electrode assembly.

[0057] The electrode assembly was placed inside a battery case, an electrolyte was injected into the case, and the top of the case was sealed with a cap assembly to fabricate a cylindrical secondary battery. The electrolyte was prepared by dissolving 1M LiPF6 in a mixed organic solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7.

[0058] Comparative Example 1 A cylindrical secondary battery was manufactured in the same manner as in Example 1, except that the ceramic filament tape was not attached to the end of the positive electrode.

[0059] <Experimental example: Performance evaluation of cylindrical secondary batteries> The cylindrical secondary batteries prepared in the examples and comparative examples were charged at a constant current of 0.3 C at 25° C. until the voltage reached 4.2 V. After charging, the cells were rested for about 50 hours and the voltage change over time was measured and shown in FIG.

[0060] 5, it can be seen that the voltage retention ratio is higher when a ceramic-containing film member is attached to the end of the positive electrode according to one embodiment of the present invention than when it is not. That is, it can be assumed that separator damage occurred in Comparative Example 1, while separator damage was prevented in Example 1 by the introduction of the ceramic-containing film member. [Explanation of symbols]

[0061] 1, 1a, 1b separator 2 negative electrode 21 Negative electrode uncoated area 21a Negative electrode uncoated area 2a Negative active material layer 2b Negative electrode current collector 3 Positive electrode 3a Cathode active material layer 3b Positive electrode current collector 31 Ceramic-containing film component 31a: Region provided with ceramic-containing film member 50 Polymer Film 51 Ceramic 10 Top Cap 20 Safety Vent 30 CID filters T-notch 40 Electrode tab 32 Gasket 60 Bead section 70 Crimping part 100 Cylindrical secondary battery 120 Electrode assembly 130 Battery Can 140 Cap Assembly 150 center pin

Claims

1. a positive electrode including a positive electrode current collector and a positive electrode active material layer formed on at least one surface of the positive electrode current collector; a negative electrode including a negative electrode current collector and a negative electrode active material layer formed on at least one surface of the negative electrode current collector; an electrode assembly in a wound state, the electrode assembly including a separator interposed between the positive electrode and the negative electrode, one end of the negative electrode in the longitudinal direction toward the center of the winding is a negative electrode uncoated portion on which no negative electrode active material layer is formed, The electrode assembly for a secondary battery includes a ceramic-containing film member at one of both longitudinal ends of the positive electrode that is closest to the center of the winding.

2. The electrode assembly for a secondary battery according to claim 1 , wherein the ceramic-containing film member is provided in an area that is the same as or larger than the area of ​​the negative electrode uncoated portion across the separator.

3. The electrode assembly for a secondary battery according to claim 1 , wherein the ceramic-containing film member is provided on both sides of the positive electrode.

4. 2. The electrode assembly for a secondary battery according to claim 1, wherein an end of the positive electrode active material layer coincides with an end of the positive electrode current collector at an end toward the center of winding, among both longitudinal ends of the positive electrode.

5. 2. The electrode assembly for a secondary battery according to claim 1, wherein the ceramic-containing film member has a tensile strength of 200 N / cm to 400 N / cm.

6. 2. The electrode assembly for a secondary battery according to claim 1, wherein the ceramic-containing film member is a polymer film having a melting point of 130[deg.] C. or higher to which ceramic is added.

7. 7. The electrode assembly for a secondary battery according to claim 6, wherein the area of ​​the exposed ceramic on the surface of the ceramic-containing film member that contacts the separator is 5% or more of the total area of ​​the ceramic-containing film member.

8. 7. The electrode assembly for a secondary battery according to claim 6, wherein the polymer is at least one selected from the group consisting of polyimide, polypropylene, polyethylene terephthalate, polystyrene, polycarbonate, and polysulfone.

9. The ceramic is made of glass fiber, tungsten carbide, and Al. ２ O ３ , Cr ２ O ３ , SiO ２ , MnO, ZnO, SnO, PbO, TiO ２ , B ４ C, TiC, SiC, AlN, Si ３ N ４ , MgB ２ , TiB ２ , TiAl, NiTi, and Al ２ Si ２ O ５ (OH) ４ The electrode assembly for a secondary battery according to claim 6 , wherein the electrode assembly is at least one selected from the group consisting of:

10. 2. The electrode assembly for a secondary battery according to claim 1, wherein the ceramic-containing film member has ceramic introduced therein in stripes that are horizontal to the winding direction of the electrode laminate.

11. The electrode assembly for a secondary battery according to any one of claims 1 to 10; a battery can in which the electrode assembly is housed; a cap assembly that seals the open end of the battery can.

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