Electrode assembly and electrochemical device

Abstract

The application discloses an electrode assembly and an electrochemical device, comprising a first electrode sheet, a separator, a second electrode sheet, a first tab and a second tab. The separator is arranged between the first electrode sheet and the second electrode sheet, the polarities of the first electrode sheet and the second electrode sheet are opposite; the first tab is connected to the first electrode sheet; the second tab is connected to the second electrode sheet; the separator comprises a separator body, a first heat insulation layer block and a second heat insulation layer block, the first heat insulation layer block is connected to one side of the separator body close to the first tab, the first heat insulation layer block is opposite to the first tab, the second heat insulation layer block is connected to one side of the separator body close to the second tab, and the second heat insulation layer block is opposite to the second tab.

Description

Technical Field

[0001] This application relates to the field of electrochemical energy storage technology, and in particular to an electrode assembly and an electrochemical device. Background Technology

[0002] The battery cell of an electrochemical device includes an electrode assembly, which comprises a first electrode, a separator, a second electrode, a first tab, and a second tab. The first and second electrodes have opposite polarities. The first tab is connected to the first electrode, and the second tab is connected to the second electrode. In current electrode assemblies, the current at the first and second tabs is relatively large during charging and discharging, resulting in high temperatures at these locations. This could cause thermal shrinkage of the separator at the corresponding tab location, potentially leading to a short circuit risk at the connection point between the first and second electrodes. Utility Model Content

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes an electrode assembly that can reduce the risk of thermal shrinkage of the insulating membrane at the corresponding tab location.

[0004] This application also proposes an electrochemical device having the above-described electrode assembly.

[0005] An electrode assembly according to a first aspect of this application includes a first electrode, a separator, a second electrode, a first tab, and a second tab. The separator is disposed between the first electrode and the second electrode, the first electrode and the second electrode having opposite polarities; the first tab is connected to the first electrode; the second tab is connected to the second electrode; the separator includes a separator body, a first heat-insulating layer block, and a second heat-insulating layer block, the first heat-insulating layer block being connected to the side of the separator body near the first tab and opposite to the first tab, and the second heat-insulating layer block being connected to the side of the separator body near the second tab and opposite to the second tab.

[0006] The electrode assembly according to the first aspect of this application has at least the following beneficial effects: by providing a first heat insulation block on the side of the separator membrane near the first electrode tab, with the first heat insulation block facing the first electrode tab, the high temperature near the first electrode tab is not easily conducted to the separator body; by providing a second heat insulation block on the side of the separator membrane near the second electrode tab, with the second heat insulation block facing the second electrode tab, the high temperature near the second electrode tab is not easily conducted to the separator body, thereby suppressing the risk of thermal shrinkage of the separator membrane at the corresponding electrode tab position, and thus reducing the risk of short circuit between the first electrode and the second electrode at the connection electrode tab position.

[0007] According to some embodiments of this application, the electrode assembly has a wound structure, at least two first tabs are provided and spaced apart along the length direction of the first electrode sheet, at least two first heat insulation layer blocks are arranged at intervals along the length direction of the separator, and the first heat insulation layer blocks are opposite to the first tabs one by one, at least two second tabs are provided and spaced apart along the length direction of the second electrode sheet, at least two second heat insulation layer blocks are arranged at intervals along the length direction of the separator, and the second heat insulation layer blocks are opposite to the second tabs one by one.

[0008] According to some embodiments of this application, the first electrode sheet is provided with a first electrode tab groove, the first electrode tab is connected to the first electrode tab groove, the first electrode tab groove is rectangular, and the projection of the first electrode tab groove along the thickness direction of the separator film is entirely within the range of the first heat insulation layer block; the second electrode sheet is provided with a second electrode tab groove, the second electrode tab is connected to the second electrode tab groove, the second electrode tab groove is rectangular, and the projection of the second electrode tab groove along the thickness direction of the separator film is entirely within the range of the second heat insulation layer block.

[0009] According to some embodiments of this application, the first heat insulation block is rectangular, with dimension A along the length of the insulating membrane and dimension B along the width of the insulating membrane. The first tab groove is C along the length of the first electrode and dimension D along the width of the first electrode, satisfying A > C and B > D. The second heat insulation block is rectangular, with dimension E along the length of the insulating membrane and dimension F along the width of the insulating membrane. The second tab groove is G along the length of the second electrode and dimension H along the width of the second electrode, satisfying E > G and F > H.

[0010] According to some embodiments of this application, the coating tolerance of the separator is J, the coating allowance of the separator is K, the first heat insulation layer satisfies: A=C+J+2K, and B=D+J+K; the second heat insulation layer satisfies E=G+J+2K, and F=H+J+K.

[0011] According to some embodiments of this application, the first electrode is configured as an aluminum electrode, the second electrode is configured as a nickel electrode, the thickness of the first heat insulation layer is X, and the thickness of the second heat insulation layer is Y, satisfying X > Y.

[0012] According to some embodiments of this application, the thickness of the first heat insulation layer block satisfies: 3μm≤X≤6μm.

[0013] According to some embodiments of this application, the thickness of the second heat insulation layer block satisfies: 2μm≤Y≤5μm.

[0014] According to some embodiments of this application, the diaphragm body includes a mesh base layer and ceramic layers connected to both sides of the mesh base layer along the thickness direction.

[0015] An electrochemical device according to a second aspect of this application includes the electrode assembly described above.

[0016] The electrochemical device according to the second aspect of this application has at least the following beneficial effects: due to the use of the above-described electrode assembly, the electrochemical device is less prone to the risk of short circuit between the first electrode and the second electrode, and its resistance to needle penetration is improved, resulting in higher stability in use.

[0017] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 This is a cross-sectional schematic diagram of the electrode assembly according to an embodiment of this application;

[0020] Figure 2 This is a cross-sectional schematic diagram of a partial structure of the electrode assembly according to an embodiment of this application;

[0021] Figure 3 This is an exploded view of a partial structure of the electrode assembly according to an embodiment of this application.

[0022] Figure label:

[0023] First electrode plate 100, first electrode ear canal 110;

[0024] Separator 200, membrane body 210, first heat insulation layer 220, second heat insulation layer 230;

[0025] Second electrode plate 300, second electrode ear canal 310;

[0026] First pole ear 400;

[0027] Second pole ear 500. Detailed Implementation

[0028] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0029] In the description of this application, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0030] In the description of this application, "multiple" refers to two or more. The use of "first" and "second" is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or the order in which the technical features are indicated.

[0031] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0032] There are also some existing separator membranes 200 that have an integral heat insulation strip along their length edges, resulting in good overall heat insulation at the edges of the separator membrane 200. However, this type of separator membrane 200 requires a large amount of heat insulation material, and the heat insulation layer in some areas is opposite to the tabs, while the heat insulation layer in other areas is offset from the tabs, resulting in a low effective utilization rate of the heat insulation layer.

[0033] Reference Figures 1 to 3 The electrode assembly of this embodiment includes a first electrode 100, a separator 200, a second electrode 300, a first tab 400, and a second tab 500. The separator 200 is disposed between the first electrode 100 and the second electrode 300, and the first electrode 100 and the second electrode 300 have opposite polarities. The first tab 400 is connected to the first electrode 100; the second tab 500 is connected to the second electrode 300. The separator 200 includes a separator body 210, a first heat insulation layer 220, and a second heat insulation layer 230. The first heat insulation layer 220 is connected to the side of the separator body 210 near the first tab 400 and is opposite to the first tab 400. The second heat insulation layer 230 is connected to the side of the separator body 210 near the second tab 500 and is opposite to the second tab 500.

[0034] By providing a first heat insulation block 220 on the side of the separator 200 near the first tab 400, with the first heat insulation block 220 facing the first tab 400, the high temperature near the first tab 400 is not easily conducted to the separator body 210. By providing a second heat insulation block 230 on the side of the separator 200 near the second tab 500, with the second heat insulation block 230 facing the second tab 500, the high temperature near the second tab 500 is not easily conducted to the separator body 210, thereby suppressing the risk of thermal shrinkage of the separator 200 at the corresponding tab position, and thus reducing the risk of short circuit between the first electrode 100 and the second electrode 300 at the connection tab position.

[0035] Specifically, the first heat insulation layer 220 and the second heat insulation layer 230 are made of the same material, namely inorganic ceramic material and organic aramid material, which makes the heat insulation layer have strong thermal stability and low thermal conductivity, which can effectively block heat diffusion. This makes the structure of the isolation membrane 200 relatively stable and not easy to shrink in a relatively high temperature environment.

[0036] In the embodiment, reference Figure 1 and Figure 2 The electrode assembly has a wound structure. Two or more first tabs 400 are provided and are arranged at intervals along the length direction of the first electrode 100. Two or more first heat insulation blocks 220 are arranged at intervals along the length direction of the separator 200. The first heat insulation blocks 220 are opposite to the first tabs 400. Two or more second tabs 500 are provided and are arranged at intervals along the length direction of the second electrode 300. Two or more second heat insulation blocks 230 are arranged at intervals along the length direction of the separator 200. The second heat insulation blocks 230 are opposite to the second tabs 500.

[0037] There is a gap between the first insulation layer blocks 220, that is, no insulation layer is provided between two adjacent first insulation layer blocks 220; there is a gap between the second insulation layer blocks 230, that is, no insulation layer is provided between two adjacent second insulation layer blocks 230. Therefore, it is not necessary to arrange insulation layers at the entire edge of the isolation membrane 200, which helps to reduce the material consumption of insulation layers and reduce material costs, maintains a good insulation effect, and makes the effective utilization rate of insulation layers high.

[0038] Specifically, the first electrode 100 can be connected to two, three or more first tabs 400, and the corresponding insulating membrane 200 can also be provided with two, three or more first heat insulation blocks 220. Those skilled in the art can choose according to actual needs; the second electrode 300 can be connected to two, three or more second tabs 500, and the corresponding insulating membrane 200 can also be provided with two, three or more second heat insulation blocks 230. Those skilled in the art can choose according to actual needs.

[0039] In the embodiment, reference Figure 2 and Figure 3 The first electrode 100 is provided with a first electrode ear groove 110, and a first electrode ear 400 is connected to the first electrode ear groove 110. The first electrode ear groove 110 is rectangular, and the projection of the first electrode ear groove 110 along the thickness direction of the separator 200 is entirely within the range of the first heat insulation layer block 220. The second electrode 300 is provided with a second electrode ear groove 310, and a second electrode ear 500 is connected to the second electrode ear groove 310. The second electrode ear groove 310 is rectangular, and the projection of the second electrode ear groove 310 along the rear direction of the separator 200 is entirely within the range of the second heat insulation layer block 230.

[0040] The first heat insulation layer 220 mentioned above can effectively block the high heat generated at the first tab 400 from being transferred to the diaphragm body 210, and the second heat insulation layer 230 mentioned above can effectively block the high heat generated at the second tab 500 from being transferred to the diaphragm body 210, resulting in a better user experience.

[0041] In the embodiment, reference Figure 2 and Figure 3 The first heat insulation block 220 is rectangular, with dimension A along the length of the separator 200 and dimension B along the width of the separator 200. The first electrode groove 110 has dimension C along the length of the first electrode 100 and dimension D along the width of the first electrode 100, satisfying A > C and B > D. The second heat insulation block 230 is rectangular, with dimension E along the length of the separator 200 and dimension F along the width of the separator 200. The second electrode groove 310 has dimension G along the length of the second electrode 300 and dimension H along the width of the second electrode 300, satisfying E > G and F > H.

[0042] The length and width of the first heat insulation layer 220 are both larger than the length and width of the first electrode groove 110, so that the projection of the first electrode groove 110 along the thickness direction of the separator 200 can be entirely within the range of the first heat insulation layer 220; the length and width of the second heat insulation layer 230 are both larger than the length and width of the second electrode groove 310, so that the projection of the second electrode groove 310 along the thickness direction of the separator 200 can be entirely within the range of the second heat insulation layer 230, thus better meeting the heat insulation requirements of the separator 200.

[0043] In the embodiment, reference Figure 2 and Figure 3The coating tolerance of the separator 200 is J, and the coating allowance is K. The first heat insulation layer 220 satisfies: A=C+J+2K, and B=D+J+K; the second heat insulation layer 230 satisfies: E=G+J+2K, and F=H+J+K. Specifically, both the first heat insulation layer 220 and the second heat insulation layer 230 are manufactured by coating heat insulation material. During the coating of the separator 200, the coating equipment has coating tolerances. Therefore, when the length and width dimensions of the first heat insulation layer 220 and the second heat insulation layer 230 satisfy the above relationships, under the existing production methods, the waste of heat insulation material can be reduced, the utilization rate of the heat insulation layer can be made more efficient, and the heat insulation effect can be maintained at a high level.

[0044] Specifically, in this application, the coating tolerance is 2mm≤J≤4mm. The coating tolerance can be selected from, for example, 2mm, 2.5mm, 3mm, 3.5mm or 4mm, or any value between the two values. Those skilled in the art can make specific selections according to actual needs.

[0045] Specifically, in this application, the coating allowance is 1mm≤K≤2mm. The coating allowance can be selected, for example, 1mm, 1.5mm or 2mm, or any value between the two values. Those skilled in the art can make specific selections according to actual needs.

[0046] In the embodiment, reference Figure 2 and Figure 3 The first electrode 400 is configured as an aluminum electrode, and the second electrode 500 is configured as a nickel electrode. The thickness of the first heat insulation layer 220 is X, and the thickness of the second heat insulation layer 230 is Y, satisfying X > Y. Aluminum electrodes are typically used for positive electrodes, and nickel electrodes are typically used for negative electrodes. During the charging and discharging process of the battery cell, due to the differences in conductivity, current carrying capacity, and thermal stability between the aluminum and nickel tabs, and the increased resistance of the aluminum tabs due to oxidation or poor contact, the heating degree of the aluminum tabs is usually significantly greater than that of the nickel tabs. Therefore, when the thickness of the first heat insulation layer 220 is greater than that of the second heat insulation layer 230, that is, the heat insulation capacity of the first heat insulation layer 220 is greater than that of the second heat insulation layer 230, it is more reasonable to use the thicker first heat insulation layer 220 to insulate the aluminum tab with a higher heating degree, and to use the relatively thinner second heat insulation layer 230 to insulate the nickel tab with a relatively lower heating degree. The use of the heat insulation layer is more flexible and the utilization rate of the heat insulation material is improved.

[0047] In the embodiment, reference Figure 2 The thickness of the first insulation layer 220 satisfies: 3μm≤X≤6μm. The aforementioned thickness of the first insulation layer 220 can meet the insulation requirements of conventional aluminum tabs, and the utilization rate of the insulation material is relatively high.

[0048] In the embodiment, reference Figure 2 The thickness of the second insulation layer 230 satisfies the following condition: 2μm ≤ Y ≤ 5μm. The aforementioned thickness of the second insulation layer 230 meets the insulation requirements of conventional nickel tabs and demonstrates a high utilization rate of the insulation material.

[0049] Specifically, in this application, the first electrode 100 is a positive electrode, and the first tab 400 is a positive tab; the second electrode 300 is a negative electrode, and the second tab 500 is a negative tab. It is conceivable that in some other embodiments, the first electrode 100 may also be a negative electrode, with the corresponding first tab 400 being a negative tab; in this case, the second electrode 300 is a positive electrode, and the second tab 500 is a positive tab.

[0050] In this embodiment, the diaphragm body 210 includes a mesh base layer and ceramic layers connected to both sides of the mesh base layer along its thickness direction. The diaphragm body 210 employs a composite structure, exhibiting good mechanical strength and wettability. Specifically, the mesh base layer is made of PPS material, and the ceramic coating is one or more of zirconium dioxide, alumina, and boehmite, along with a hydrophilic polymer material. Combined with the first insulation layer 220 and the second insulation layer 230, the overall puncture resistance is strong, contributing to improved needle puncture resistance of the separator 200.

[0051] This application also discloses an electrochemical device employing the aforementioned electrode assembly. Due to the use of this electrode assembly, the electrochemical device is less prone to the risk of short circuit between the first electrode 100 and the second electrode 300, and its resistance to needle penetration is improved, resulting in higher stability in use.

[0052] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0053] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. An electrode assembly, characterized in that, include: A first electrode (100), a separator (200), and a second electrode (300), wherein the separator (200) is disposed between the first electrode (100) and the second electrode (300), and the first electrode (100) and the second electrode (300) have opposite polarities; The first electrode tab (400) is connected to the first electrode plate (100); The second electrode tab (500) is connected to the second electrode plate (300); The insulating membrane (200) includes a membrane body (210), a first heat insulation block (220), and a second heat insulation block (230). The first heat insulation block (220) is connected to the side of the membrane body (210) near the first tab (400) and is opposite to the first tab (400). The second heat insulation block (230) is connected to the side of the membrane body (210) near the second tab (500) and is opposite to the second tab (500).

2. The electrode assembly according to claim 1, characterized in that: The electrode assembly has a wound structure. At least two first tabs (400) are provided and are arranged at intervals along the length direction of the first electrode (100). At least two first heat insulation blocks (220) are arranged at intervals along the length direction of the separator (200). The first heat insulation blocks (220) are opposite to the first tabs (400). At least two second tabs (500) are provided and are arranged at intervals along the length direction of the second electrode (300). At least two second heat insulation blocks (230) are arranged at intervals along the length direction of the separator (200). The second heat insulation blocks (230) are opposite to the second tabs (500).

3. The electrode assembly according to claim 1, characterized in that: The first electrode (100) is provided with a first electrode tab groove (110), and the first electrode tab (400) is connected to the first electrode tab groove (110). The first electrode tab groove (110) is rectangular, and the projection of the first electrode tab groove (110) along the thickness direction of the insulating membrane (200) is entirely within the range of the first heat insulation layer block (220). The second electrode (300) is provided with a second electrode tab groove (310), and the second electrode tab (500) is connected to the second electrode tab groove (310). The second electrode tab groove (310) is rectangular, and the projection of the second electrode tab groove (310) along the thickness direction of the insulating membrane (200) is entirely within the range of the second heat insulation layer block (230).

4. The electrode assembly according to claim 3, characterized in that: The first heat insulation block (220) is rectangular. The dimension of the first heat insulation block (220) along the length direction of the isolation membrane (200) is A, and the dimension of the first heat insulation block (220) along the width direction of the isolation membrane (200) is B. The dimension of the first tab groove (110) along the length direction of the first electrode plate (100) is C, and the dimension of the first tab groove (110) along the width direction of the first electrode plate (100) is D, satisfying A > C and B > D. The second heat insulation block (230) is rectangular. The dimension of the second heat insulation block (230) along the length direction of the isolation membrane (200) is E, and the dimension of the second heat insulation block (230) along the width direction of the isolation membrane (200) is F. The dimension of the second tab groove (310) along the length direction of the second electrode plate (300) is G, and the dimension of the second tab groove (310) along the width direction of the second electrode plate (300) is H, satisfying E > G and F > H.

5. The electrode assembly according to claim 4, characterized in that: The coating tolerance of the isolation membrane (200) is J, the coating allowance of the isolation membrane (200) is K, the first heat insulation block (220) satisfies: A=C+J+2K, and B=D+J+K; the second heat insulation block (230) satisfies E=G+J+2K, and F=H+J+K.

6. The electrode assembly according to claim 1, characterized in that: The first electrode (400) is configured as an aluminum electrode, the second electrode (500) is configured as a nickel electrode, the thickness of the first heat insulation block (220) is X, and the thickness of the second heat insulation block (230) is Y, satisfying X > Y.

7. The electrode assembly according to claim 6, characterized in that: The thickness of the first heat insulation layer (220) satisfies: 3μm≤X≤6μm.

8. The electrode assembly according to claim 6, characterized in that: The thickness of the second heat insulation layer (230) satisfies: 2μm≤Y≤5μm.

9. The electrode assembly according to claim 1, characterized in that: The diaphragm body (210) includes a mesh base layer and ceramic layers connected to both sides of the mesh base layer along the thickness direction.

10. An electrochemical device, characterized in that, Includes the electrode assembly as described in any one of claims 1 to 9.

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