Electrode assembly

Abstract

The electrode assembly of the present invention can prevent the separator from folding by providing a protective block composed of a first protective panel and a second protective panel extending perpendicularly from one side of the first protective panel in a) a corner in the length direction, b) a corner in the width direction, or c) a corner in both the length direction and the width direction of the electrode stack.

Description

[Technical field]

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2021-0134888 filed on October 12, 2021, and Korean Patent Application No. 10-2022-0129405 filed on October 11, 2022, and all contents disclosed in the documents of the relevant Korean patent applications are incorporated as part of this specification.

[0002] The present invention relates to an electrode assembly that includes a protective block. [Background technology]

[0003] The development of portable electronic devices such as mobile phones and laptops has led to a rapid increase in the demand for secondary batteries as their energy source. Recently, the use of secondary batteries as the power source for hybrid electric vehicles (HEVs) and electric vehicles (EVs) has become a reality. As a result, much research has been conducted into secondary batteries that can meet various requirements. In particular, the demand for lithium secondary batteries with high energy density, high discharge voltage and output is on the rise.

[0004] However, lithium secondary batteries have a fundamental problem of low safety. If a defect such as a micro short occurs at a local part of the battery element during use of the secondary battery, it can cause phenomena such as an internal temperature rise and gas generation, and the shape of the internal elements such as the electrodes can be deformed due to the temperature rise and gas generation. Such shape deformation can accelerate the occurrence of additional short circuits and also increase the possibility of the battery catching fire due to the short circuit.

[0005] A lithium secondary battery includes an electrode assembly in which a positive electrode and a negative electrode, each coated with a positive active material and a negative active material, are disposed with a separator therebetween, and a battery case, which is an exterior material that hermetically houses the electrode assembly together with an electrolyte.

[0006] The electrode assembly, which is composed of an electrode laminate having a positive electrode / separator / negative electrode structure constituting the lithium secondary battery, can be largely classified into a jelly roll type (wound type), a stack type, and a mixed type of these, a stack / folding type, depending on its structure.

[0007] The jelly roll type electrode assembly is manufactured by coating the metal foil used as the current collector with an electrode active material, drying and pressing it, cutting it into a band shape of a desired width and length, separating the anode and cathode using a separator, and winding it into a spiral shape. The jelly roll type electrode assembly is suitable for cylindrical batteries.

[0008] The stack type or stack / fold type electrode assembly has a structure in which positive and negative electrode units are sequentially stacked with a separator sandwiched between the electrode laminates, and it is easy to obtain a rectangular shape.

[0009] Stack type or stack / fold type lithium secondary batteries can be made by repeatedly stacking mono cells with a positive electrode / separator / negative electrode / separator structure, folding them using a continuous separator film, or adding positive electrodes above and below a half cell with a separator / negative electrode / separator structure.

[0010] Meanwhile, in stack type or stack / fold type lithium secondary batteries, low voltage defective cells may be found, in which the battery exhibits a voltage drop exceeding the self-discharge rate, and this is mainly caused by the edge of the separator being folded or torn during the assembly process, causing the positive and negative electrodes to directly face each other and thus causing an electrical short circuit between them.Therefore, there is a need to develop an electrode assembly that can solve the above problems. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Korean Patent Publication No. 10-2018-0081926 Summary of the Invention [Problem to be solved by the invention]

[0012] As a result of extensive research to solve the above problems, it was found that if the corners of the electrode stack are covered with a protection block consisting of a first protection panel and a second protection panel extending perpendicularly from one side of the first protection panel in the overall length direction, the phenomenon of the separator being bent or torn does not occur.

[0013] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide an electrode assembly in which a separator is not damaged. [Means for solving the problem]

[0014] In order to achieve the above objective, The present invention relates to an electrode laminate; a protective block for enclosing the corners of the electrode stack; and a fixing tape wound on the outer surface of the electrode stack and the outer surface of the protection block in a full width direction or full length direction; The protection block provides an electrode assembly including a first protection panel and a second protection panel extending perpendicularly from one side of the first protection panel in the overall length direction.

[0015] In one embodiment of the invention, the protection block comprises: a) Wrapping the corners of the electrode laminate along its entire length; b) Electrode tab of electrode laminate B Enveloping the corners in the full width direction excluding c) The overall length and thickness of the electrode stack B It may also be one that covers the corners in the entire width direction excluding the corners. In one embodiment of the present invention, the number of protective blocks a) surrounding the corners in the full length direction of the electrode stack may be four, and each protective block may be provided at one of the corners in the full length direction of the electrode stack.

[0016] In one embodiment of the present invention, the electrode layer of the electrode laminate B The number of protective blocks surrounding the corners in the entire width direction excluding the corners may be four, and one may be provided at each corner in the entire width direction of the electrode stack.

[0017] In one embodiment of the present invention, the number of protective blocks surrounding the corners of the electrode stack in the overall length direction is four, B The number of protective blocks surrounding the corners in the overall width direction excluding the corners may be four, and one may be provided at each of the corners in the overall length direction and the overall width direction of the electrode stack.

[0018] In one embodiment of the present invention, each guard block may have a separation distance to an adjacent guard block.

[0019] In one embodiment of the present invention, the protective block may be made of one or more materials selected from the group consisting of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide, ethylene vinyl acetate, and acrylate-based compounds.

[0020] In an embodiment of the present invention, the fixing tapes may be provided at a plurality of positions and positioned so as to be spaced apart from each other.

[0021] In one embodiment of the present invention, the fixing tape may be wound around the outer surface of the electrode stack and the outer surface of the protection block in the full width direction by one or more turns.

[0022] In an embodiment of the present invention, the fixing tapes may be fixed at symmetrical positions based on a full-width line at a midpoint in the full-length direction of the electrode assembly.

[0023] In one embodiment of the present invention, the fixing tape may be wound around the outer surface of the electrode stack and the outer surface of the protection block in the overall length direction by one or more turns.

[0024] In an embodiment of the present invention, the fixing tapes may be fixed at symmetrical positions based on a full-length line on a midpoint in a full-width direction of the electrode assembly.

[0025] In an embodiment of the present invention, the electrode stack may have a separator interposed between a positive electrode and a negative electrode, and a length in a total length direction of the electrode stack may be longer than a length in a total width direction perpendicular to the total length direction. Effect of the Invention

[0026] The electrode assembly of the present invention has a protective block formed of a first protective panel and a second protective panel extending perpendicularly from one side of the first protective panel in the overall length direction at a) a corner in the overall length direction, b) a corner in the overall width direction, or c) each of the corners in the overall length direction and the overall width direction of the electrode laminate, thereby preventing a phenomenon in which the separator is folded.

[0027] In addition, by preventing the separator from folding, the problem of battery short circuit caused by the separator folding can be solved. [Brief description of the drawings]

[0028] [Figure 1] 1 is a perspective view of an electrode assembly according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a front view of an electrode assembly according to an embodiment of the present invention. [Diagram 3] FIG. 4 is a perspective view of an electrode assembly according to another embodiment of the present invention. [Figure 4] FIG. 4 is a perspective view of an electrode assembly according to another embodiment of the present invention. [Diagram 5] FIG. 1 is a perspective view of a conventional electrode assembly. [Figure 6] 1 is a photograph showing a separator folded in a conventional electrode assembly. [Figure 7] FIG. 2 is a front view of an electrode assembly 200 including an alternative form of protective block 220. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may, however, be embodied in several different forms and should not be construed as limited to the embodiments set forth herein.

[0030] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0031] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited manner based on their ordinary or dictionary meaning, but should be interpreted in a meaning and concept that corresponds to the technical idea of ​​the present invention, based on the principle that an inventor can appropriately define the concept of a term in order to explain his / her invention in the best possible manner.

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may, however, be embodied in several different forms and should not be construed as limited to the embodiments set forth herein.

[0033] The present invention relates to an electrode assembly, and the electrode assembly 100 of the present invention is electrode stack 110; A protective block 120 that encases the corners of the electrode stack 110; and A fixing tape 130 is wound on the outer surface of the electrode stack 110 and the outer surface of the protection block 120 in the width direction or the entire length direction; The protection block 120 includes a first protection panel 121 and a second protection panel 122 extending perpendicularly from one side of the first protection panel 121 in the overall length direction.

[0034] The protective block 120 that encases the corners of the electrode stack 110 is a) Wrapping the corners of the electrode laminate 110 in the overall length direction y; b) Electrode tabs of the electrode laminate 110 BEncompassing the corners in the width direction x except for 111a and 112a, or c) The overall length direction y of the electrode laminate 110 and the electrode B It may be one that covers all corners in the width direction x excluding 111a and 112a.

[0035] The protection block 120 may be composed of a first protection panel 121 and a second protection panel 122 extending in a perpendicular direction from one side of the first protection panel 121 in the overall length direction.

[0036] Specifically, for example, the protection block 120 is TIFF0007652483000001.tif2947" may have a shape similar to the character.

[0037] Also, the first and second protection panels 121 and 122 may have a shape similar to a rectangle.

[0038] In addition, the protective block 120 is a high-strength insulating material, and specifically, may be a block made of one or more materials selected from the group consisting of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide, ethylene vinyl acetate, and acrylate-based compounds.

[0039] The fixing tapes 130 may serve to maintain the shape of the electrode assembly 100 from being deformed, and may be provided at a plurality of positions and positioned to be spaced apart from each other.

[0040] In an embodiment of the present invention, the fixing tape 130 may be wound around the outer surface of the electrode stack 110 and the outer surface of the protection block 120 in the width direction x by one or more turns.

[0041] Also, the fixing tapes 130 may be fixed at symmetrical positions based on a full-width line at a midpoint in the full-length direction y of the electrode assembly 100 .

[0042] The fixing tapes 130 may preferably be three to five in number.

[0043] In another embodiment of the present invention, the fixing tape 130 may be wound on the outer surface of the electrode stack 110 and the outer surface of the protection block 120 in the overall length direction y by one or more turns.

[0044] Also, the fixing tapes 130 may be fixed at symmetrical positions based on a full length line at the midpoint of the electrode assembly 100 in the full width direction x.

[0045] The fixing tapes 130 may preferably be two to four in number.

[0046] FIG. 1 is a perspective view of an electrode assembly according to an embodiment of the present invention, and FIG. 2 is a front view of the electrode assembly according to an embodiment of the present invention.

[0047] 1 and 2, an electrode assembly 100 according to one embodiment of the present invention may include an electrode stack 110; a protective block 120 that encloses corners of the electrode stack 110 in a full-length direction y; and a fixing tape 130 that is wound in a full-width direction x on an outer surface of the electrode stack 110 and an outer surface of the protective block 120.

[0048] The number of the protection blocks 120 may be four, one at each corner in the overall length direction y of the electrode stack 110. Also, the protection blocks 120 may have a separation distance from each other.

[0049] The area of ​​the electrode assembly 100 covered by the protective block 120 is not particularly limited, and may be, for example, 30 to 70% of the total surface area of ​​the outer periphery of the electrode assembly 100 in the overall length direction y.

[0050] The fixing tape 130 may be wrapped around the outer surface of the electrode stack 110 and the outer surface of the protective block 120 in the full-length direction y, but when the protective block 120 covers a corner in the full-length direction y, it is preferable that the fixing tape 130 is wrapped around the outer surface of the electrode stack 110 and the outer surface of the protective block 120 in the full-width direction x.

[0051] FIG. 3 is a perspective view of an electrode assembly according to another embodiment of the present invention.

[0052] Referring to FIG. 3, an electrode assembly 100 according to another embodiment of the present invention includes an electrode stack 110; B It may include a protection block 120 that covers the corners in the width direction x except for 111a and 112a, and a fixing tape 130 that is wound on the outer surface of the electrode stack 110 and the outer surface of the protection block 120 in the overall length direction y.

[0053] The protection blocks 120 are four in number, and the electrode terminals of the electrode stack 110 are B One protection block may be provided at each corner in the width direction x, except for 111a and 112a. Also, the protection block 120 may have a separation distance from adjacent protection blocks.

[0054] If the protective block 120 covers the entire corner of the entire width direction x, B Since disconnection may occur in 111a and 112a, the protection block 120 is B The electrode may be arranged to cover the corners in the width direction x except for the corners 111a and 112a. B The protection blocks 120 provided at the corners of the width direction x except for the corners 111a and 112a are formed by a second protection panel 122 extending vertically from one side of the first protection panel 121 in the full length direction. B It may be an extension from the portion excluding 111a and 112a.

[0055] The area of ​​the electrode assembly 100 covered by the protective block 120 is not particularly limited, and may be, for example, 30 to 70% of the total surface area of ​​the outer circumferential surface of the electrode assembly 100 in the width direction x.

[0056] The fixing tape 130 may be wrapped around the outer surface of the electrode stack 110 and the outer surface of the protective block 120 in the full-width direction x, but when the protective block 120 covers a corner in the full-width direction x, it is preferable that the fixing tape 130 is wrapped around the outer surface of the electrode stack 110 and the outer surface of the protective block 120 in the full-length direction y.

[0057] FIG. 4 is a perspective view of an electrode assembly according to another embodiment of the present invention.

[0058] 4, an electrode assembly 100 according to another embodiment of the present invention includes an electrode stack 110; B It may also include a protective block 120 that covers the corners in the width direction x excluding 111a and 112a, and a plurality of fixing tapes 130 that are wound on the outer surface of the electrode stack 110 and the outer surface of the protective block 120 in the width direction x.

[0059] The number of the protection blocks 120 is eight, specifically, four protection blocks are provided at each corner of the electrode stack 110 in the overall length direction y. B There may be four protection blocks, one at each corner in the width direction x, excluding 111a and 112a. Also, the protection blocks 120 may have a separation distance from adjacent protection blocks.

[0060] If the protective block 120 covers the entire corner of the entire width direction x, B Since disconnection may occur in 111a and 112a, the protection block 120 is B The electrode may be arranged to cover the corners in the width direction x except for the corners 111a and 112a. BThe protection blocks 120 provided at the corners of the width direction x except for 111a and 112a are formed by a second protection panel 122 extending vertically from one side of the first protection panel 121 in the length direction. B It may be an extension from the portion excluding 111a and 112a.

[0061] The area of ​​the electrode assembly 100 covered by the protective block 120 is not particularly limited, and may be, for example, 30 to 70% of the total surface area of ​​the outer circumferential surface of the electrode assembly 100 in the width direction x and length direction y.

[0062] The fixing tape 130 may be wrapped around the outer surface of the electrode stack 110 and the outer surface of the protective block 120 in the full-length direction y, but when the protective block 120 covers corners in the full-width direction x and full-length direction y, it is preferable that the fixing tape 130 is wrapped around the outer surface of the electrode stack 110 and the outer surface of the protective block 120 in the full-length direction y.

[0063] The electrode assembly 100 of the present invention includes the above-mentioned protective block 120, which prevents the end of the separator 113 from being exposed to the outside. This prevents the separator from being folded due to an external force caused by injection of an electrolyte, etc., and solves problems such as battery short circuit. In addition, the electrode assembly 100 can be protected from external impact.

[0064] The protective block 120 is arranged in the longitudinal direction y of the electrode stack 110 and in the longitudinal direction of the electrode stack 110. B The folding phenomenon of the separator can be most effectively prevented when the protective block 120 a) covers the corners in the full-width direction x of the electrode stack 110 except for the corners 111a and 112a. B This may be more effective than covering all corners in the width direction x except for 111a and 112a. That is, the larger the area covered by the protection block 120, the more effectively the folding phenomenon of the separator caused by an external force can be prevented.

[0065] The electrode stack 110 may have a separator 113 interposed between a positive electrode 111 and a negative electrode 112, and may have a length in a total length direction y of the electrode stack 110 that is longer than a length in a total width direction x perpendicular to the total length direction y.

[0066] The electrode stack 110 may be a stack type electrode stack 110 including a plurality of unit cells, each having a separator 113 interposed between a positive electrode 111 and a negative electrode 112. The electrode stack 110 may also be an electrode stack 110 in which the outermost layer of the electrode stack 110 is made of a separator. In addition to this, a lamination / stack type electrode stack in which a plurality of unit cells are laminated may also be used, and the structure of the electrode stack 110 may be applied to all of the electrode stacks 110 described in this specification.

[0067] The positive electrode 111 is a positive electrode terminal. B 111a, and the negative electrode 112 is a negative electrode terminal B 112a.

[0068] FIG. 5 is a perspective view of a conventional electrode assembly.

[0069] Referring to FIG. 5, a conventional electrode assembly 10 includes an electrode stack 20 and a fixing tape 30 wound around the outer surface of the electrode stack 20 in a full width direction x.

[0070] The electrode stack 20 and fixing tape 30 are the same as those of the present invention described above.

[0071] The conventional electrode assembly 10 does not include a protection block that encloses the corners of the electrode stack in the overall length direction, and the separator is exposed to the outside.

[0072] In general, the electrode assembly is subjected to external forces from all directions, and the areas other than the areas wrapped with multiple fixing tapes are vulnerable to the external forces. In particular, the edges of the separator are more vulnerable to external forces, and even a small external force can cause the separator to fold (Figure 6).

[0073] However, the electrode assembly 100 according to one embodiment of the present invention includes a protection block 120 composed of a first protection panel 121 and a second protection panel 122 extending perpendicularly from one side of the first protection panel in the overall length direction. The protection block 120 is provided at each of a) a corner in the overall length direction y, b) a corner in the overall width direction x, or c) a corner in the overall length direction y and the overall width direction x of the electrode stack 110, so that the separator is not exposed to the outside, and the above-mentioned problem of the separator being folded due to an external force can be solved.

[0074] FIG. 7 is a front view of the electrode assembly 200 including the protective blocks 220 that encase the corners and sides of the electrode stack 210 in the overall length direction y.

[0075] Referring to FIG. 7, the protection block 220 may be composed of a rectangular panel 221 and two extensions 222 extending from both ends of the rectangular panel 221 in the full length direction in the same direction perpendicular to the rectangular panel 221.

[0076] Specifically, for example, the protection block 220 is TIFF0007652483000002.tif5249" may have a shape similar to the character.

[0077] Also, the two extensions 222 may have a shape similar to a rectangle.

[0078] When the electrode stack 210 is inserted into the protective block 220, if the inner height of the protective block 220 is not sufficient during the insertion process, the separator 213 may be folded by an external force, or the anode 212 or the cathode 211 may be damaged. In addition, if the inner height of the protective block 220 is higher than the height of the electrode stack 210, the electrode stack 210 may move inside the protective block 220, causing damage.

[0079] However, in the electrode assembly 100 according to the embodiment of the present invention, the protection block 120 including the first protection panel 121 and the second protection panel 122 extending in a perpendicular direction from one side of the first protection panel in the overall length direction is disposed at a) a corner in the overall length direction y of the electrode stack 110, b) an electrode tab. B 111a, 112a except for the corners in the width direction x, or c) the full length direction y and the electrode B The protection blocks 120 are provided at each corner in the width direction x except for 111a and 112a, and are spaced apart from adjacent protection blocks. Therefore, the problems occurring in the protection block 220 shown in FIG. 7 can be solved as described above.

[0080] That is, in the electrode assembly 100 according to the embodiment of the present invention, the separator 113 does not fold, and therefore problems such as battery short circuit can be solved.

[0081] As described above, the present invention has been described using limited examples and drawings, but the present invention is not limited thereto, and it is of course possible for a person having ordinary knowledge in the technical field to which the present invention pertains to make various modifications and variations within the technical spirit of the present invention and the equivalent scope of the following claims. [Explanation of symbols]

[0082] 10, 100, 200: Electrode assembly 20, 110, 210: Electrode laminate 111, 211: Positive electrode 21a, 111a: Positive electrode B 112, 212: negative electrode 22a, 112a: negative electrode B 113, 213: Separation membrane 120, 220: Protective blocks 121: First protective panel 122: Second protective panel 30, 130: Fixed tape 221: Square Panel 222: Extension

Claims

1. Electrode stack; A protective block that encases the corners of the electrode stack; and a fixing tape wound on an outer surface of the electrode stack and an outer surface of the protection block in a full width direction or full length direction; the protection block includes a first protection panel and a second protection panel extending perpendicularly from one side of the first protection panel in the overall length direction, The protection block is b) wrapping the corners of the electrode stack in the width direction excluding the electrode tabs; or c) wrapping the corners of the electrode stack along its entire length and its entire width, excluding the electrode tabs; Electrode assembly.

2. The protective block b) covers corners of the electrode stack in the overall width direction excluding the electrode tabs, b) the number of the protection blocks surrounding the corners in the entire width direction excluding the electrode tabs of the electrode laminate is four; The electrode assembly according to claim 1 , wherein the electrode laminate is provided at each of its corners in the width direction.

3. The protective block c) covers the corners of the electrode stack in the overall length direction and the overall width direction excluding the electrode tabs; c) the number of the protection blocks surrounding the corners in the full length direction of the electrode stack is four, and the number of the protection blocks surrounding the corners in the full width direction excluding the electrode tabs is four; The electrode assembly according to claim 1 , wherein the electrode laminate is provided at each of corners in the overall length and width directions.

4. 4. The electrode assembly of claim 1, wherein each guard block has a separation distance to an adjacent guard block.

5. 2. The electrode assembly according to claim 1, wherein the protective block is a block made of one or more materials selected from the group consisting of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide, ethylene vinyl acetate, and acrylate-based compounds.

6. The electrode assembly of claim 1 , wherein the fixing tape is provided at a plurality of positions and positioned so as to be spaced apart from each other.

7. The electrode assembly according to claim 1 , wherein the fixing tape is wound around the outer surface of the electrode stack and the outer surface of the protection block in a width direction thereof at least once.

8. 2. The electrode assembly according to claim 1, wherein the plurality of fixing tapes are fixed at positions symmetrical with respect to a full width line on a midpoint of the electrode assembly in the overall length direction.

9. The electrode assembly according to claim 1 , wherein the fixing tape is wound around the outer surface of the electrode stack and the outer surface of the protection block at least once in the overall length direction.

10. 2. The electrode assembly according to claim 1, wherein the fixing tapes are fixed at positions symmetrical with respect to a full-length line on a midpoint in a full-width direction of the electrode assembly.

11. In the electrode stack, a separator is interposed between a positive electrode and a negative electrode, The electrode assembly of claim 1 , wherein a length in a total length direction of the electrode stack is longer than a length in a total width direction perpendicular to the total length direction.

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