Battery cell electrode sheet, battery cell, battery, battery pack, and electric device

Abstract

Disclosed are a battery cell electrode sheet, a battery cell, a battery, a battery pack, and an electric device. The battery cell electrode sheet comprises: a substrate, comprising a tab region and a coating region, wherein the tab region is located on one side of the coating region in a first direction; and a grafting member, extending from the end portion of the battery cell electrode sheet in the first direction toward the coating region and covering at least part of at least one surface of the tab region. In the solution of the present disclosure, the grafting member extends from the end portion of the battery cell electrode sheet in the first direction toward the coating region and covers at least part of the at least one surface of the tab region, and forms a tab together with the tab region, such that the current-carrying area of the tab can be increased, thereby reducing the internal resistance of the tab and improving the current-carrying capability of the tab, effectively mitigating the problem of excessive temperature rise of the tab during fast charging.

Description

An electrode tab of an electric cell, an electric cell, a battery, a battery pack and an electric device

[0001] Cross Reference to Related Applications

[0002] The present disclosure claims the priority of the Chinese patent publication with the publication number 202421540815.4 and the publication name "An electrode tab of an electric cell, an electric cell, a battery, a battery pack and an electric device" filed on July 1, 2024 with the Chinese Patent Office, the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of batteries, in particular to an electrode tab of an electric cell, an electric cell, a battery, a battery pack and an electric device. BACKGROUND

[0004] With the continuous acceleration of the pace of life, people hope that electronic products can be charged in a shorter time to obtain higher use frequency and better practical experience, which puts higher requirements on the fast charging performance of the battery.

[0005] However, the tab of the electrode tab in the battery in the related art is generally a single-layer foil material with a relatively small thickness, and the overcurrent area of the tab is small, which leads to a too high temperature rise of the tab during fast charging of the battery, and further leads to that the fast charging performance of the battery cannot meet the market demand and affects the service life and safety performance of the battery. SUMMARY

[0006] In view of the existing problems, the present disclosure provides an electrode tab, which comprises:

[0007] a base material comprising a tab area and a coating area, wherein the tab area is located on one side of the coating area along a first direction;

[0008] a grafting piece covering at least part of the surface of the tab area from the end of the electrode tab along the first direction towards the coating area.

[0009] Exemplarily, the grafting piece is welded to the tab area.

[0010] Exemplarily, the grafting piece covers at least part of the surface of the tab area and is welded to the tab area through at least one weld seam; or,

[0011] the grafting piece is in a U-shaped structure as a whole and covers at least part of the surface of the end of the electrode tab along the first direction and the tab area, and is welded to the tab area through at least one weld seam;

[0012] The welds extend along a second direction, which is perpendicular to the first direction.

[0013] The grafting member is welded to the tab area by the welds which are spaced along the first direction.

[0014] The welds have a width along the first direction which is greater than or equal to 1 mm.

[0015] The welds are made by an ultrasonic roll welding process.

[0016] A coating is further included, which covers at least one surface of the coated area of the substrate.

[0017] The thickness of the grafting member on the surface of the tab area is less than or equal to the thickness of the coating on the surface of the coated area on the same side.

[0018] The electrode tab is a positive electrode tab, the substrate is a smooth aluminum foil, and the coating is a positive active material coating; or,

[0019] The electrode tab is a negative electrode tab, the substrate is a smooth copper foil, and the coating is a negative active material coating.

[0020] When the electrode tab is the positive electrode tab, the grafting member is a smooth aluminum foil;

[0021] When the electrode tab is the negative electrode tab, the grafting member is a smooth copper foil.

[0022] Another aspect of the present disclosure provides an electrode, including a positive electrode tab, a negative electrode tab, and a separator, the separator being disposed between the positive electrode tab and the negative electrode tab, wherein at least one of the positive electrode tab and the negative electrode tab includes the electrode tab described above.

[0023] The positive electrode tab, the negative electrode tab, and the separator are wound to form a wound electrode; or,

[0024] The positive electrode tab, the negative electrode tab, and the separator are stacked to form a stacked electrode.

[0025] Another aspect of the present disclosure provides a battery, including a housing, a cover, and the electrode described above, the housing and the cover enclosing a receiving space, and the electrode being received in the receiving space.

[0026] Another aspect of the present disclosure provides a battery pack, including the battery described above.

[0027] Another aspect of the present disclosure provides a power consuming device comprising the battery described above, or comprising the battery pack described above.

[0028] According to the electrode tab of the battery cell, the battery cell, the battery, the battery pack and the power consuming device of the present disclosure, the grafting member in the electrode tab covers at least part of the surface of the tab area from the end of the electrode tab along the first direction towards the coating area, and forms a tab with the tab area, thereby reducing the internal resistance of the tab and improving the overcurrent capacity of the tab, effectively improving the problem of excessive temperature rise of the tab during fast charging. BRIEF DESCRIPTION OF DRAWINGS

[0029] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the figures. The drawings provided in connection with the present disclosure are intended to further explain, by way of example, various embodiments of the present disclosure, and constitute a part of this specification. The drawings provided in connection with the present disclosure do not constitute an entire scope of the present disclosure, and are used to explain the present disclosure together with embodiments of the present disclosure, and do not constitute a limitation of the present disclosure. In the drawings, like reference numerals refer to like parts or steps throughout the figures.

[0030] FIG. 1A shows a structural schematic diagram of an electrode tab of a related art battery cell;

[0031] FIG. 1B shows a structural schematic diagram of an electrode tab of a related art battery cell wound to form a jelly-roll type battery cell;

[0032] FIG. 2 shows a structural schematic diagram of an electrode tab of an embodiment of the present disclosure;

[0033] FIG. 3 shows a view of the electrode tab in FIG. 2 along the A-A direction according to an embodiment of the present disclosure;

[0034] FIG. 4 shows an enlarged view of the area in FIG. 3 according to an embodiment of the present disclosure;

[0035] FIG. 5 shows a structural schematic diagram of an electrode tab according to another embodiment of the present disclosure;

[0036] FIG. 6 shows a view of the electrode tab in FIG. 5 along the A-A direction according to an embodiment of the present disclosure;

[0037] FIG. 7 shows an enlarged view of the area in FIG. 6 according to an embodiment of the present disclosure;

[0038] FIG. 8 shows a structural schematic diagram of an electrode tab wound to form a jelly-roll type battery cell according to an embodiment of the present disclosure.

[0039] Reference numerals: 110 - substrate; 120 - coating layer; 210 - substrate; 220 - grafting member; 230 - coating layer; 240 - weld. DETAILED DESCRIPTION

[0040] In the following description, numerous specific details are set forth to provide a more thorough understanding of the present disclosure. However, it will be apparent to one of skill in the art upon

[0041] It should be understood that the present disclosure can be carried out in many different forms without necessarily departing from the spirit or scope of the present disclosure. Rather, these examples are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. In the drawings, the sizes and relative sizes of layers and regions can be exaggerated for clarity. Like reference numerals can be used to denote like elements throughout.

[0042] It should be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present disclosure.

[0043] Spatially relative terms, such as "beneath", "below", "lower", "under", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0044] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0045] In the related art, as shown in FIGS. 1A and 1B, the electrode tab of the battery generally includes a substrate 110 and a coating layer 120. The substrate 110 includes a coated area and a tab area, and the tab area is located on one side of the coated area along a first direction. The coating layer 120 covers both surfaces of the coated area of the substrate. The tab area serves as the tab of the electrode tab, and the tab of the electrode tab in the related art is a single-layer substrate with a relatively small thickness. The overcurrent area of the tab is small, which leads to a high temperature rise of the tab during fast charging of the battery, and further leads to that the fast charging performance of the battery cannot meet the market demand, and affects the service life and safety performance of the battery.

[0046] It should be noted that although the electrode tab shown in FIGS. 1A and 1B has the tab area located on both sides of the coated area along the first direction, this is an intermediate product produced to improve production efficiency. In the actual electrode tab used in the battery, the tab area is located on one side of the coated area along the first direction. Taking the electrode tab wound into a wound electrode shown in FIG. 1B as an example, the electrode tab is wound into a wound electrode along a direction perpendicular to the first direction. After winding is completed, the wound electrode is cut to form two electrodes symmetrically arranged along the first direction. The tab area of the electrode tab in each electrode is located on one side of the coated area along the first direction.

[0047] In view of the above technical problems, the present disclosure provides an electrode tab, an electrode, a battery, a battery pack and an electrical equipment to solve the above problems.

[0048] Referring to FIGS. 2 to 7, an electrode tab according to an embodiment of the present disclosure is exemplarily described. As shown in FIGS. 2 to 7, the electrode tab of the present disclosure includes a substrate (also referred to as a current collector) 210 and a grafting piece 220, wherein: the substrate 210 includes a tab area and a coated area, and the tab area is located on one side of the coated area along a first direction; and the grafting piece 220 covers at least part of the area of at least one surface of the tab area from the end of the electrode tab along the first direction towards the coated area. The tab area of the substrate 210 and the grafting piece 220 together constitute the tab of the electrode tab. Exemplarily, the first direction can be the length direction or the width direction of the electrode tab, and the present disclosure does not limit this.

[0049] It is worth mentioning that although the structure of the electrode tab of the battery cell shown in FIGS. 2 and 5 is that the tab area is located on both sides of the coated area along the first direction, this is an intermediate product produced for the purpose of improving production efficiency, and in the actual battery cell used in the battery, the tab area is located on one side of the coated area along the first direction, which is equivalent to cutting the battery cell tab shown in FIGS. 2 and 5 into two battery cell tabs symmetrical along the first direction after manufacturing, and the tab area in each battery cell tab is located on one side of the coated area along the first direction; or, after manufacturing the jelly-roll type battery cell shown in FIG. 8, cutting the battery cell tab into two battery cells symmetrical along the first direction, and the tab area in the battery cell tab of each battery cell is located on one side of the coated area along the first direction.

[0050] In the above-mentioned scheme, the tab of the battery cell tab of the present disclosure is equivalent to additionally providing a grafting member on the tab area of the substrate, and the outer end of the tab along the first direction is connected with the cover plate of the battery to realize the flow of current, and the grafting member covers at least part of the area of at least one surface of the tab area from the end of the battery cell tab along the first direction towards the coated area, which can increase the contact area connected with the cover plate on the basis of the original tab area, i.e. can increase the overcurrent area of the tab, thereby reducing the internal resistance of the tab and improving the overcurrent capacity of the tab, effectively improving the problem of excessive temperature rise of the tab during fast charging.

[0051] In one example, as shown in FIGS. 2 to 7, the battery cell tab of the present disclosure further comprises a coating layer 230 covering at least one surface of the coated area of the substrate 210. Preferably, the coating layer 230 covers both surfaces of the coated area.

[0052] In one example, the battery cell tab can be a positive electrode tab or a negative electrode tab, when the battery cell tab is a positive electrode tab, the substrate 210 is an aluminum foil with a smooth surface, and the coating layer 230 is a positive active material coating layer; when the battery cell tab is a negative electrode tab, the substrate 210 is a copper foil with a smooth surface, and the coating layer 230 is a negative active material coating layer. Exemplarily, the substrate 210 can also be of other suitable materials, which are not limited by the present disclosure.

[0053] Specifically, the material of the positive active material coating layer can be lithium-containing olivine-type phosphates, lithium transition metal oxides and their respective modified compounds. The lithium-containing olivine-type phosphates can include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP for short)), a composite of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite of lithium manganese iron phosphate and carbon, but are not limited to the above examples. The material of the negative active material coating layer can be at least one of artificial graphite, natural graphite, mesocarbon microbeads, hard carbon, soft carbon, silicon, silicon-oxygen, silicon-carbon and silicon alloy, but is not limited to the above examples.

[0054] In one example, when the electrode tab of the battery cell is a positive electrode tab, the grafting piece 220 is a smooth aluminum foil; when the electrode tab of the battery cell is a negative electrode tab, the grafting piece 220 is a smooth copper foil. Preferably, the material of the grafting piece 220 is the same as the material of the base material of the electrode tab of the battery cell. Illustratively, the material of the grafting piece can also be any other suitable material, which is not limited in the present disclosure.

[0055] In one example, the grafting piece 220 is welded to the tab area.

[0056] In one example, as shown in FIGS. 2-4, the grafting piece 220 is in a U-shaped structure as a whole, covering at least part of the area of the end of the electrode tab along the first direction and covering at least part of the area of both surfaces of the tab area, and being welded to the tab area by at least one welding seam 240. Illustratively, the grafting piece 220 should cover at least part of the area of each of the two surfaces of the tab area. Illustratively, since the grafting piece 220 is an integrally formed U-shaped structure, the grafting piece is naturally and tightly connected to the end of the electrode tab, so that only one welding seam is needed to tightly weld the grafting piece 220 to the tab area. Illustratively, the welding seam should be close to one end of the grafting piece 220 of the U-shaped structure, away from the end of the electrode tab.

[0057] In another example, as shown in FIGS. 5-7, the grafting piece 220 covers at least part of the area of one surface of the tab area and is welded to the tab area by at least one welding seam 240. Illustratively, the grafting piece 220 covers at least part of the area of one surface of the tab area from the end of the electrode tab along the first direction towards the coating area.

[0058] In one example, the grafting piece 220 is welded to the tab area by a plurality of welding seams 240 arranged at intervals along the first direction. Where the grafting piece 220 is in a U-shaped structure as a whole, covering at least part of the area of the end of the electrode tab along the first direction and covering at least part of the area of both surfaces of the tab area, although only one welding seam 240 can achieve the tight connection of the grafting piece 220 to the tab area, the present disclosure does not specifically limit the number of welding seams 240; where the grafting piece 220 covers at least part of the area of one surface of the tab area, since the grafting piece 220 only covers at least part of the area of one surface of the tab area, the grafting piece 220 is not naturally and tightly connected to the end of the electrode tab, and if there is only one welding seam 240, the area of the grafting piece 220 away from the welding seam 240 is prone to curling, wrinkling and other problems, and preferably a plurality of welding seams 240 are needed to tightly weld the grafting piece 220 to the tab area.

[0059] In one example, no matter whether the grafting piece 220 only covers at least part of the surface of the tab area or the grafting piece 220 covers at least part of the surfaces of the tab area, the grafting piece 220 extends from the end of the electrode tab along the first direction to cover the tab area of the coating area. In the battery in which the electrode tab is located, the end of the electrode tab along the first direction forms the tab area, and the tab is formed by welding the grafting piece 220 at the end to connect with the external circuit. The contact area of the end of the tab connected with the external circuit can be effectively increased, and the internal resistance of the tab can be reduced and the overcurrent area of the tab can be increased, effectively improving the problem of excessive temperature rise of the tab during fast charging of the battery.

[0060] In one example, the welding seam 240 extends along the second direction, and the second direction is perpendicular to the first direction. For example, if the first direction is the length direction of the electrode tab, the second direction is the width direction of the electrode tab; if the first direction is the width direction of the electrode tab, the second direction is the length direction of the electrode tab.

[0061] In one example, the width of the welding seam 240 along the first direction is greater than or equal to 1 mm, for example, the width of the welding seam 240 along the first direction can be 1 mm, 2 mm, 4 mm, 5.5 mm, etc. Preferably, the width of the welding seam 240 along the first direction ranges from 2 mm to 5 mm, for example, 2 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, etc.

[0062] In one example, the welding seam 240 is made by an ultrasonic roll welding process. In other embodiments, the welding seam 240 can also be made by various welding processes conventional in the art, which are not limited in the present disclosure.

[0063] In one example, the thickness of the grafting piece 220 on the surface of the tab area should be less than or equal to the thickness of the coating 230 on the surface of the coating area on the same side, so as to prevent the electrode tab from being unable to be processed into an electrode cell due to the thickness of the grafting piece 220 being greater than the coating 230, for example, being unable to be wound to form a wound electrode cell.

[0064] So far, the structure of the electrode tab of the present disclosure has been introduced. The complete electrode tab can also include other component structures, which are not described here.

[0065] In summary, the grafting piece in the electrode tab of the present disclosure covers at least part of the surface of the tab area from the end of the electrode tab along the first direction to the coating area, and forms a tab with the tab area, thereby reducing the internal resistance of the tab and improving the overcurrent capacity of the tab, effectively improving the problem of excessive temperature rise of the tab during fast charging, improving the safety of the battery in which the electrode tab is located, and prolonging the service life of the battery.

[0066] The embodiments of the present disclosure further provide an electric core, which comprises a positive electrode sheet, a negative electrode sheet and a separation layer, wherein at least one of the positive electrode sheet and the negative electrode sheet comprises the electric core sheet described above. The separation layer is arranged between the positive electrode sheet and the negative electrode sheet to prevent the positive electrode sheet and the negative electrode sheet from directly contacting and causing short circuit. Exemplarily, the separation layer and the coating layer of the positive electrode sheet and the coating layer of the negative electrode sheet are all formed with pores for ion movement.

[0067] In one example, as shown in FIG. 8, the positive electrode sheet, the negative electrode sheet and the separation layer are wound to form a wound electric core, more specifically, the positive electrode sheet, the negative electrode sheet and the separation layer are wound along a direction perpendicular to the first direction to form the wound electric core; or the positive electrode sheet, the negative electrode sheet and the separation layer are laminated to form a laminated electric core. It is worth noting that FIG. 8 shows an intermediate product of the wound electric core formed for the purpose of improving efficiency. After the wound electric core as shown in FIG. 8 is manufactured, the electric core sheet will be cut into two electric cores symmetrical along the first direction, and the tab area in the electric core sheet of each electric core is located on one side of the coating area along the first direction. Exemplarily, the tabs of the positive electrode sheet and the tabs of the negative electrode sheet in the wound electric core and the laminated electric core are located on the same side. Exemplarily, before the positive electrode sheet, the negative electrode sheet and the separation layer are wound or laminated, a step of die cutting the tabs of the positive electrode sheet and the tabs of the negative electrode sheet is further included to remove part of the tabs to make the shape of the tabs meet the requirements. Exemplarily, before the positive electrode sheet, the negative electrode sheet and the separation layer are wound or laminated, a step of slitting the positive electrode sheet, the negative electrode sheet and the separation layer is further included.

[0068] In one example, taking the wound electric core formed by winding the positive electrode sheet, the negative electrode sheet and the separation layer and the negative electrode sheet as the electric core sheet described above as an example, in the manufacturing process, a conventional negative electrode sheet is first provided, i.e. a negative electrode sheet only comprising a base material and a coating layer is provided, and a grafting piece is also provided; then the grafting piece is welded to the tab area of the base material; finally, the welded negative electrode sheet is wound or laminated with the positive electrode sheet and the separation layer.

[0069] In one example, the shape of the electric core can be a short electric core or a long electric core with a relatively thin thickness, or a rectangular block-shaped electric core with a slightly thicker thickness, which can be, for example but not limited to, a square aluminum shell electric core, etc. The shape of the electric core can also be a cylindrical electric core.

[0070] The introduction to the structure of the electric core of the present disclosure is completed so far. The complete electric core can further comprise other component structures, which are not described herein.

[0071] In summary, at least one of the positive electrode tab and the negative electrode tab of the battery cell of the present disclosure includes the battery cell tab described above, the grafting member in the battery cell tab covers at least part of the surface of the tab area from the end of the battery cell tab along the first direction towards the coating area, and forms a tab with the tab area, thereby reducing the internal resistance of the tab and improving the overcurrent capacity of the tab, effectively improving the problem of excessive temperature rise of the tab during fast charging, improving the safety of the battery and prolonging the service life of the battery.

[0072] The present disclosure also provides a battery, which includes a shell, a cover plate, and the battery cell described above. The shell and the cover plate form an accommodation space, and the battery cell is accommodated in the accommodation space.

[0073] In one example, the tab in the battery cell tab in the battery is generally connected with the cover plate to achieve electrical connection with the external circuit, and the tab in the battery cell tab in the present disclosure is jointly formed by the tab area of the original base material and the welded grafting member, which can effectively increase the contact area of the tab and the cover plate, thereby reducing the internal resistance of the tab and improving the overcurrent capacity of the tab, effectively improving the problem of excessive temperature rise of the tab during fast charging, improving the safety of the battery and prolonging the service life of the battery.

[0074] In one example, a plurality of battery cells are arranged in the battery, and an exhaust channel is arranged between any adjacent battery cells. The exhaust channel can be used to prevent the accumulation of gas inside the battery between the battery cells, thereby avoiding safety problems such as swelling, cracking, and even explosion of the battery. The exhaust channel is arranged in the cross beam or the longitudinal beam between the adjacent battery cells.

[0075] In one example, a cold plate is further arranged on the top and / or bottom of the battery cell, and the cold plate is bonded to the battery cell by a heat-conducting structural adhesive for controlling the temperature of the battery cell.

[0076] The structure of the battery of the present disclosure has been introduced so far. For a complete battery, other component structures can also be included, which are not described here.

[0077] The present disclosure also provides a battery pack, which includes the battery described above. For a complete battery pack, other component structures can also be included, which are not described here.

[0078] The present disclosure also provides an electric device, which includes the battery described above or the battery pack described above. The electric device includes an electric vehicle, a hybrid vehicle, and an industrial device, all of which are within the protection scope of the present disclosure.

[0079] While example embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the example embodiments are only exemplary and not intended to limit the scope of the disclosure. Those of ordinary skill in the art can make various changes and modifications of the embodiments described herein without departing from the scope and spirit of the disclosure. All such changes and modifications are intended to be included within the scope of the disclosure as defined in the appended claims.

[0080] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the disclosure can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0081] Similarly, it is to be understood that the various features of the disclosure described herein are sometimes individually referenced in each of the examples, drawings, and description of the disclosure. However, these are not intended to be mutually exclusive aspects of the disclosure. Rather, the individual feature(s) can be combined in any combination so long as the technical effects of the disclosure are preserved. Thus, each of the dependent claims appended hereto incorporates text of the independent claims in their entirety and should be afforded like scope.

[0082] Those skilled in the art will appreciate that all features described herein (including all accompanying claims, abstract and drawings), and steps of any method or process so described, can be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Each feature will be understood to be present in every embodiment comprising said feature whether or not the feature is recited in the same claim or described in the abstract.

[0083] Furthermore, those skilled in the art will recognize that references in the specification to "one embodiment", "an embodiment", "an example embodiment", mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily referring to a single, "one embodiment".

[0084] It is noted that the foregoing examples have been presented by way of explanation of the present disclosure, not limitation. Variations on the examples as well as numerous combinations thereof are possible without departing from the scope of the present disclosure.

Claims

An electrode tab of an electric cell, characterized by The application relates to an electrode tab of a battery cell, comprising: a base material (210) comprising a tab area and a coating area, wherein the tab area is located on one side of the coating area along a first direction; a grafting member (220) covering at least part of the surface of the tab area from the end of the electrode tab along the first direction towards the coating area. The electrode tab of claim 1, wherein The grafting member (220) is welded to the tab area. The electrode tab of claim 2, wherein The grafting member (220) covers at least part of the surface of the tab area and is welded to the tab area through at least one welding seam (240); or, The grafting member (220) is in a U-shaped structure as a whole and covers at least part of the surface of the tab area and the end of the electrode tab along the first direction, and is welded to the tab area through at least one welding seam (240); The welding seam (240) extends along a second direction, and the second direction is perpendicular to the first direction. The electrode tab of claim 3, wherein The grafting member (220) is welded to the tab area through a plurality of welding seams (240) arranged at intervals along the first direction. The electrode tab of claim 3, wherein The width of the welding seam (240) along the first direction is greater than or equal to 1 mm. The electrode tab of claim 3, wherein The welding seam (240) is made through an ultrasonic roll welding process. The electrode tab of any one of claims 1 to 6, wherein Further comprising a coating layer (230) covering at least one surface of the coating area of the base material (210). The electrode tab of claim 7, wherein The thickness of the grafting member (220) on the surface of the tab area is less than or equal to the thickness of the coating layer (230) on the surface of the coating area located on the same side. According to claim 7, wherein The electrode tab is a positive electrode tab, the base material (210) is a smooth aluminum foil, and the coating layer (230) is a positive active material coating layer (230); or The electrode tab is a negative electrode tab, the base material (210) is a smooth copper foil, and the coating layer (230) is a negative active material coating layer (230). The electrode tab of claim 9, wherein When the electrode tab is the positive electrode tab, the grafting member (220) is a smooth aluminum foil; When the electrode tab is the negative electrode tab, the grafting member (220) is a smooth copper foil. An electric double layer capacitor comprising: The application relates to a battery cell, comprising a positive electrode tab, a negative electrode tab and a separator, wherein at least one of the positive electrode tab and the negative electrode tab comprises the electrode tab according to any one of claims 1-10. The electric cell according to claim 11, wherein The positive electrode tab, the negative electrode tab and the separator are wound to form a wound battery cell; or The positive electrode tab, the negative electrode tab and the separator are laminated to form a laminated battery cell. A battery characterized by The application relates to a battery, comprising a shell, a cover plate and the battery cell according to any one of claims 11-12, wherein the shell and the cover plate form a containing space, and the battery cell is arranged in the containing space. A battery pack characterized by The application relates to a battery according to claim 13. An electric device characterized by comprising: The application relates to a battery according to claim 13 or a battery pack according to claim 14.

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