Pole piece, electrochemical device, and electronic device

Abstract

The application relates to the technical field of electrochemical energy storage, in particular to a pole piece, an electrochemical device and an electronic equipment. The pole piece comprises a current collector, an active material layer, a tab, a bonding piece and an insulating coating. In the thickness direction, the current collector comprises opposite first and second sides. The active material layer is arranged on at least one side of the current collector, and the active material layer and the current collector enclose a containing groove. The tab is partially located in the containing groove, and the tab is connected to the current collector. The bonding piece is located in the containing groove, and the bonding piece is connected to and covers one side of the tab away from the current collector. The insulating coating is located in the containing groove, and the insulating coating is distributed around the outer periphery of the tab. The electrochemical device comprises the pole piece, and the electronic equipment comprises the electrochemical device. The pole piece, the electrochemical device and the electronic equipment can improve the energy density of the electrochemical device.

Description

Technical Field

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

[0002] In the field of electrochemical energy storage technology, in order to avoid problems such as short circuits and lithium plating around the tabs, adhesive tape is usually applied to the tabs and welding positions. However, applying adhesive tape will increase the overall thickness of the battery cell, which will reduce the energy density of the electrochemical device. Utility Model Content

[0003] This application aims to address at least one of the technical problems existing in the prior art. To achieve the above objective, this application proposes an electrode capable of improving the energy density of electrochemical devices.

[0004] This application also proposes an electrochemical device including the aforementioned electrodes.

[0005] This application also proposes electronic devices that include the aforementioned electrochemical devices.

[0006] To solve the above-mentioned technical problems, this application provides an electrode sheet, including a current collector, an active material layer, a tab, an adhesive, and an insulating coating; Along the thickness direction, the current collector includes a first side and a second side opposite to each other; An active material layer is disposed on at least one side of the current collector, and the active material layer and the current collector enclose a receiving groove; The tab portion is located in the receiving groove, and the tab is connected to the current collector; The adhesive is located in the receiving groove, and the adhesive connects to and covers the side of the electrode tab away from the current collector; The insulating coating is located in the receiving groove and is distributed around the outer periphery of the electrode tab.

[0007] The electrode sheet according to the embodiments of this application has at least the following beneficial effects: By attaching adhesive paper to the electrode tab and arranging an insulating coating on the outer periphery of the electrode tab, this application can effectively block the electrode tab and effectively avoid problems such as short circuit and lithium plating caused by high current density around the electrode tab. On this basis, by setting a receiving groove, this application can accommodate the electrode tab, adhesive and insulating coating in the receiving groove, avoiding the increase in thickness caused by local outward protrusion of the electrode sheet, thereby helping to improve the energy density of the electrochemical device.

[0008] According to some embodiments of this application, the electrode includes a plurality of receiving grooves, including a first receiving groove and a second receiving groove. An active material layer is provided on both the first side and the second side of the current collector. The first side of the current collector and the active material layer on the same side enclose the first receiving groove, and the second side of the current collector and the active material layer on the same side enclose the second receiving groove. Both the first receiving groove and the second receiving groove contain an electrode tab, an adhesive, and an insulating coating.

[0009] According to some embodiments of this application, along the thickness direction, the first receiving groove and the second receiving groove are symmetrically arranged on the first side and the second side.

[0010] According to some embodiments of this application, at least one of the tabs, adhesive, and insulating coating is symmetrically arranged on opposite sides of the current collector along the thickness direction.

[0011] According to some embodiments of this application, the sum of the thicknesses of the tab and the adhesive is less than or equal to the depth of the receiving groove, and the thickness of the insulating coating is less than or equal to the depth of the receiving groove.

[0012] According to some embodiments of this application, the sum of the thicknesses of the tab and the adhesive is equal to the thickness of the insulating coating.

[0013] According to some embodiments of this application, within the receiving groove, the projection of the adhesive along the thickness direction covers the tab.

[0014] According to some embodiments of this application, the tabs and the active material layer are arranged at intervals, and the insulating coating includes a first insulating portion and a second insulating portion connected together. Along the width direction, the first insulating part is located between the tab and the active material layer, and the sum of the dimensions of the first insulating part and the adhesive is equal to the dimension of the receiving groove; Along the length direction, the second insulating part is located between the tab and the active material layer, and the sum of the dimensions of the second insulating part and the adhesive is equal to the dimension of the receiving groove.

[0015] This application also provides an electrochemical device comprising the electrode shown in any of the above embodiments.

[0016] The electrochemical device according to the embodiments of this application has at least the following beneficial effects: by using the above-mentioned electrode, it is beneficial to improve the energy density of the electrochemical device and effectively avoid short circuits, so as to ensure the safety of the electrochemical device.

[0017] This application also provides an electronic device that includes the electrochemical device described in the above embodiments.

[0018] The electronic device according to the embodiments of this application has at least the following beneficial effects: by employing the above-described electrochemical device, the battery life of the electronic device can be improved.

[0019] 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

[0020] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the structure of the electrode sheet in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of an electrode sheet according to another embodiment of this application; Figure 3 This is a top view of the electrode sheet in an embodiment of this application.

[0021] Reference numerals: current collector 110, first side 111, second side 112, tab 120, adhesive 130, insulating coating 140, first insulating part 141, second insulating part 142, active material layer 150; First receiving tank 210, second receiving tank 220. Detailed Implementation

[0022] 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.

[0023] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this application.

[0024] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0025] 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.

[0026] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are 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.

[0027] The embodiments of this application are described below with reference to the accompanying drawings: refer to Figures 1 to 3 According to an embodiment of this application, the electrode sheet includes a current collector 110, an active material layer 150, a tab 120, an adhesive 130, and an insulating coating 140. Along the thickness direction, the current collector 110 includes a first side 111 and a second side 112 opposite to each other. The active material layer 150 is disposed on at least one side of the current collector 110, and the active material layer 150 and the current collector 110 enclose a receiving groove. The tab 120 is partially located in the receiving groove and is connected to the current collector 110. The adhesive 130 is located in the receiving groove and connects to and covers the side of the tab 120 away from the current collector 110. The insulating coating 140 is located in the receiving groove and is distributed around the outer periphery of the tab 120. Therefore, by covering the side of the tab 120 away from the current collector 110 with the adhesive 130, and by distributing the insulating coating 140 around the outer periphery of the tab 120, the tab 120 can be protected, reducing problems such as short circuits and lithium plating caused by concentrated current density around the tab 120, thus improving the safety of the electrode. At the same time, since the active material layer 150 and the current collector 110 form a receiving groove, and a part of the tab 120, the adhesive 130 and the insulating coating 140 are all contained in the receiving groove, the local thickness of the electrode is avoided, and the electrode is flatter overall, which is beneficial to improving the energy density of the electrochemical device.

[0028] Specifically, the electrode has two mutually perpendicular thickness directions, width directions, and length directions, and can be wound along the length direction to fabricate an electrochemical device. Along the thickness direction, the current collector 110 has opposing first sides 111 and second sides 112. An active material layer 150 is disposed on at least one side of the current collector 110; that is, the active material layer 150 may be disposed only on the first side 111, only on the second side 112, or simultaneously on both sides. The active material layer 150 and the current collector 110 enclose a receiving groove, wherein the active material layer 150 constitutes the sidewall of the receiving groove, and the current collector 110 constitutes the bottom wall of the receiving groove. A portion of the tab 120 is located in the receiving groove, and another portion extends out of the receiving groove along the width direction. The portion of the tab 120 located in the receiving groove is connected to the current collector 110. Specifically, the tab 120 and the current collector 110 can be fixedly connected by welding to ensure the conductivity between them. The adhesive 130 is located in the receiving groove. The adhesive 130 is a piece of adhesive tape that connects to and completely covers the side of the tab 120 facing away from the current collector 110. Along the thickness direction, the surface of the adhesive 130 facing away from the tab 120 is closer to the current collector 110 than the surface of the active material layer 150 facing away from the current collector 110. This can also be understood as the thickness of the adhesive 130 being less than the thickness of the active material layer 150. The insulating coating 140 is located in the receiving groove. The insulating coating 140 is a mixture of ceramic and adhesive. Similarly, the thickness of the insulating coating 140 is less than the thickness of the active material layer 150. The insulating coating 140 is distributed around the outer periphery of the portion of the tab 120 located in the receiving groove. Specifically, it can connect to the current collector 110 and cover the outer periphery of the portion of the tab 120 located in the receiving groove, or it can only cover the area of ​​the current collector 110 corresponding to the outer periphery of the tab 120. Therefore, while taking into account the barrier of the tab 120, it can effectively avoid the increase in local thickness of the electrode caused by the outward protrusion of the adhesive 130 and the insulating coating 140, which is beneficial to improving the energy density of the electrochemical device.

[0029] refer to Figures 1 to 3In some embodiments, the electrode includes multiple receiving grooves, including a first receiving groove 210 and a second receiving groove 220. An active material layer 150 is provided on both the first side 111 and the second side 112 of the current collector 110. The first side 111 of the current collector 110 and the active material layer 150 on the same side enclose the first receiving groove 210, and the second side 112 of the current collector 110 and the active material layer 150 on the same side enclose the second receiving groove 220. Both the first receiving groove 210 and the second receiving groove 220 contain tabs 120, adhesives 130, and insulating coatings 140. Current transmission from both sides of the current collector 110 via at least two tabs 120 is achieved, which helps to shorten the average transmission distance of electrons within the electrode, allowing the current to be more evenly concentrated on the tabs 120 from both sides of the electrode. This avoids excessive current concentration in localized areas of the electrode, thereby helping to reduce the internal resistance of the electrode and improve the power performance and cycle life of the battery.

[0030] Specifically, along the thickness direction of the electrode, the current collector 110 has a first side 111 and a second side 112, and the active material layer 150 is simultaneously disposed on both the first side 111 and the second side 112 of the current collector 110, that is, both sides of the current collector 110 are covered by the active material layer 150. Among them, the active material layer 150 on the first side 111 of the current collector 110 and the surface of the first side 111 of the current collector 110 form a first receiving groove 210, and the active material layer 150 on the second side 112 of the current collector 110 and the surface of the second side 112 of the current collector 110 form a second receiving groove 220. The sidewalls of the grooves are formed by the active material layer 150 on the corresponding side, and the bottom wall of the grooves is formed by the surface of the current collector 110 on the corresponding side. The first receiving groove 210 houses a tab 120, an adhesive component 130, and an insulating coating 140. The second receiving groove 220 also houses a tab 120, an adhesive component 130, and an insulating coating 140. The tab 120, adhesive component 130, and insulating coating 140 in both receiving grooves are independently configured components. For the connection between the tab 120 and the current collector 110, the tab 120 in both receiving grooves is fixedly connected to the corresponding surface of the current collector 110 by welding. The adhesive 130 in both receiving slots are adhesive tapes, which cover and connect to the side of the tab 120 in the corresponding receiving slot that faces away from the current collector 110. The surface of the adhesive tape facing away from the tab 120 is closer to the current collector 110 than the surface of the active material layer 150 facing away from the current collector 110, meaning the thickness of the adhesive tape is less than the thickness of the active material layer 150. The insulating coatings 140 in both receiving slots are mixtures of ceramic and adhesive. The thickness of the insulating coatings 140 is also less than the thickness of the active material layer 150. The insulating coatings 140 are distributed around the outer periphery of the tab 120 in the corresponding receiving slot. They can connect to the corresponding surface of the current collector 110 and cover the outer periphery of the tab 120 located in the receiving slot, or they can only cover the outer periphery of the tab 120 and connect to the insulating coating 140. Providing tabs 120 on both sides of the electrode sheet allows for a more uniform current distribution, which helps reduce problems such as lithium plating and localized overheating caused by localized current concentration, thus extending the battery's cycle life. In addition, the adhesive 130 and insulating coating 140 in each receiving groove can respectively form a barrier protection for the corresponding tabs 120, reducing the risk of short circuits around the tabs 120 on both sides, which is beneficial to improving the safety of the electrode. Furthermore, the tabs 120, adhesive 130 and insulating coating 140 are all housed in the corresponding receiving groove, which can prevent local bulging on the electrode surface and help ensure the energy density of the electrochemical device.

[0031] Taking the first side 111 of the current collector 110 as an example, the specific structural arrangement of this side is as follows: The surface of the first side 111 of the current collector 110 is covered with an active material layer 150. The active material layer 150 is partially removed from the first side 111 of the current collector 110, so that the active material layer 150 and the surface of the first side 111 of the current collector 110 enclose each other to form a first receiving groove 210. The active material layer 150 constitutes the sidewall of the first receiving groove 210. The removal of the active material layer 150 results in the exposed area of ​​the current collector 110 constituting the bottom wall of the first receiving groove 210. A part of the tab 120 is located inside the first receiving groove 210. The part of the tab 120 located inside the first receiving groove 210 is fixedly connected to the surface of the first side 111 of the current collector 110 by welding to ensure that the current can be stably conducted between the tab 120 and the current collector 110. The other part of the tab 120 extends out of the first receiving groove 210 along the width direction. The adhesive 130 is an adhesive tape. The adhesive tape completely covers the side surface of the tab 120 located in the first receiving groove 210 and facing away from the current collector 110 along the thickness direction. The adhesive tape adheres to the surface of the tab 120 by its own adhesiveness. There is a height difference between the side surface of the adhesive tape facing away from the tab 120 and the top of the side wall of the first receiving groove 210 (i.e., the side surface of the active material layer 150 facing away from the current collector 110). The thickness of the adhesive tape is less than the thickness of the active material layer 150, so that the adhesive tape is confined inside the first receiving groove 210 and does not exceed the surface of the active material layer 150.

[0032] The insulating coating 140 is a mixture of ceramic and adhesive. The insulating coating 140 is fixed in the first receiving groove 210 by coating. It is continuously distributed around the outer periphery of the portion of the first receiving groove 210 surrounding the tab 120. Along the thickness direction, one side of the insulating coating 140 is in contact with the surface of the first side 111 of the current collector 110, and the other side does not exceed the surface of the active material layer 150 away from the side of the current collector 110. That is, the thickness of the insulating coating 140 is also less than the thickness of the active material layer 150.

[0033] In this structural arrangement on the first side 111, the adhesive 130 covers the side of the tab 120 facing away from the current collector 110, and the insulating coating 140 surrounds the outer periphery of the tab 120. Together, they form a protective enclosure for the tab 120, reducing the risk of short circuits between the tab 120 and surrounding components, thus improving the safety of the electrode. Simultaneously, the thickness of both the adhesive 130 and the insulating coating 140 is less than the thickness of the active material layer 150, and both are confined within the first receiving groove 210. This avoids localized increases in electrode thickness caused by protrusions from the surface of the active material layer 150, helping to maintain the flatness of the electrode. This improves space utilization when the electrode is wound into an electrochemical device, and helps maintain the energy density of the electrochemical device.

[0034] refer to Figures 1 to 3In other embodiments, there are multiple first receiving grooves 210 and multiple second receiving grooves 220. Specifically, along the thickness direction of the electrode, the current collector 110 has a first side 111 and a second side 112. The active material layer 150 covers both the first side 111 and the second side 112 of the current collector 110. On the first side 111 of the current collector 110, the active material layer 150 forms multiple recesses that are spaced apart. Each recess and the surface of the first side 111 of the current collector 110 enclose a first receiving groove 210. The multiple first receiving grooves 210 are arranged sequentially along the length direction of the electrode. Each first receiving groove 210 has a sidewall formed by the active material layer 150 at the corresponding position and a bottom wall formed by the corresponding surface of the first side 111 of the current collector 110. Similarly, on the second side 112 of the current collector 110, the active material layer 150 also forms a plurality of spaced depressions. Each depression and the surface of the second side 112 of the current collector 110 enclose a second receiving groove 220. The plurality of second receiving grooves 220 are arranged sequentially along the length of the electrode, and the structure of each second receiving groove 220 is consistent with the first receiving groove 210.

[0035] Each first receiving groove 210 independently houses an electrode tab 120, an adhesive 130, and an insulating coating 140. A portion of the electrode tab 120 is located inside the first receiving groove 210 and is fixedly connected to the surface of the first side 111 of the current collector 110 by welding to ensure stable current conduction. The other portion of the electrode tab 120 extends outside the first receiving groove 210. The adhesive 130 adheres to and covers the side of the electrode tab 120 located inside the first receiving groove 210 and facing away from the current collector 110 by its own adhesiveness. The surface of the adhesive tape facing away from the electrode tab 120 does not extend beyond the top of the corresponding sidewall of the first receiving groove 210, that is, the thickness of the adhesive tape is less than the thickness of the active material layer 150. The insulating coating 140 is fixed in the first receiving groove 210 by a coating process, surrounding the corresponding tab 120 located on the outer periphery of the portion of the first receiving groove 210. The thickness of the insulating coating 140 is also less than the thickness of the active material layer 150, and it is in contact with the surface of the first side 111 of the current collector 110. The structure, connection method and positional relationship of the tab 120, the adhesive 130 and the insulating coating 140 inside each second receiving groove 220 are consistent with the corresponding components inside the first receiving groove 210.

[0036] Therefore, by employing a structure with multiple first receiving tanks 210 and multiple second receiving tanks 220, this application creates multiple tabs 120 distributed along the length of the electrode to collect current from both sides of the current collector 110. This shortens the current transmission path, reduces the overall internal resistance of the electrode, and ensures the power performance of the electrochemical device. Furthermore, the uniform current distribution reduces the risk of lithium plating and localized overheating caused by excessive local current density, helping to extend the cycle life of the electrochemical device and ensuring its safety.

[0037] refer to Figures 1 to 3 In some embodiments, the first receiving groove 210 and the second receiving groove 220 are symmetrically arranged on the first side 111 and the second side 112 along the thickness direction. Specifically, along the thickness direction of the electrode, the projections of the first receiving groove 210 and the second receiving groove 220 in the thickness direction completely overlap, and their groove depths and opening dimensions are consistent, forming a symmetrical arrangement structure. Because the first receiving groove 210 and the second receiving groove 220 are symmetrically arranged along the thickness direction, the mass distribution and structural stress on both sides of the current collector 110 are more uniform, which helps to reduce local performance differences caused by structural unevenness. At the same time, the symmetrical arrangement allows the current paths on both sides of the current collector 110 to be completely symmetrical, further optimizing the uniformity of current distribution, which helps to reduce the risk of lithium plating and improve the cycle life of the battery.

[0038] refer to Figures 1 to 3 In some embodiments, at least one of the tabs 120, the adhesive 130, and the insulating coating 140 is symmetrically arranged on opposite sides of the current collector 110 along the thickness direction.

[0039] Specifically, along the thickness direction of the electrode sheet, the first receiving groove 210 houses an electrode tab 120, an adhesive element 130, and an insulating coating 140. The second receiving groove 220 also houses an electrode tab 120, an adhesive element 130, and an insulating coating 140. The electrode tab 120 in the first receiving groove 210 is welded to the surface of the first side 111 of the current collector 110, and the electrode tab 120 in the second receiving groove 220 is welded to the surface of the second side 112 of the current collector 110. The projections of the two electrode tabs 120 in the thickness direction completely overlap, forming a symmetrical arrangement of the electrode tabs 120 relative to the current collector 110. Alternatively, the adhesive element 130 is adhesive tape. The adhesive element 130 in the first receiving groove 210 adheres to and covers the side of the corresponding electrode tab 120 facing away from the current collector 110 through its own adhesiveness. Similarly, the adhesive element 130 in the second receiving groove 220 adheres to and covers the side of the corresponding electrode tab 120 facing away from the current collector 110. The two adhesive elements 130... The dimensions and thickness of the electrodes 120 are consistent, and they are symmetrically arranged relative to the current collector 110 in the thickness direction. And / or, the insulating coating 140 is a mixture of ceramic and adhesive. The insulating coating 140 in the first receiving groove 210 is fixed in the groove by a coating process and surrounds the outer periphery of the corresponding electrode 120. The insulating coating 140 in the second receiving groove 220 is fixed in the same way and surrounds the outer periphery of the corresponding electrode 120. The specifications and coverage of the two insulating coatings 140 are consistent, and they are symmetrically arranged relative to the current collector 110 in the thickness direction. It should be understood that the electrode 120, adhesive 130 and insulating coating 140 can be symmetrically arranged individually, or two or three can be symmetrically arranged together.

[0040] If the tabs 120 are symmetrically arranged, the current paths and conductivity on both sides of the current collector 110 tend to be consistent, which helps to reduce the internal resistance of the electrode and reduce energy loss during charging and discharging, thereby improving the power performance of the battery. If the adhesive 130 is symmetrically arranged, the coverage and adhesion of the adhesive tape on both sides to the corresponding tabs 120 are consistent, which can form a balanced protection for the tabs 120 from both sides, avoiding the risk of exposure of the tabs 120 due to insufficient protection on one side of the adhesive tape, which helps to reduce the probability of short circuits around the tabs 120 and improve the safety of the electrode. If the insulating coating 140 is symmetrically arranged, the protective effect of the insulating coating 140 on the outer periphery of the tabs 120 on both sides is consistent, which can reduce the electrical isolation failure problem caused by uneven thickness or incomplete coverage of the insulating coating 140 on one side, further enhancing the electrical safety of the electrode.

[0041] refer to Figures 1 to 3 In some embodiments, the sum of the thicknesses of the tab 120 and the adhesive 130 is less than or equal to the depth of the receiving groove, and the thickness of the insulating coating 140 is less than or equal to the depth of the receiving groove.

[0042] Specifically, along the thickness direction of the electrode, the current collector 110 has a opposite side surface, and the active material layer 150 covers the side surface of the current collector 110. The active material layer 150 and the side surface of the current collector 110 enclose a receiving groove. The depth of the receiving groove is the vertical distance from the side surface of the active material layer 150 away from the side surface of the current collector 110 to the side surface of the current collector 110, which is the thickness of the single-sided active material layer 150. A portion of the tab 120 is located within the receiving groove. The adhesive 130 is stacked with the tab 120, and the sum of the thicknesses of the tab 120 and the adhesive 130 is less than or equal to the depth of the receiving groove. This ensures that the surface of the adhesive 130 facing away from the tab 120 does not exceed the surface of the active material layer 150 facing away from the current collector 110. The thickness of the insulating coating 140 is its dimension along the thickness direction of the electrode sheet. The thickness of the insulating coating 140 is less than or equal to the depth of the receiving groove, ensuring that the surface of the insulating coating 140 facing away from the current collector 110 also does not exceed the surface of the active material layer 150 facing away from the current collector 110. Thus, both the adhesive 130 and the insulating coating 140 are completely confined within the receiving groove, resulting in a uniform overall electrode thickness. During the winding and fabrication of the electrochemical device, this reduces internal gaps caused by local protrusions, improves the space utilization of the electrode within the battery casing, and consequently enhances the energy density of the electrochemical device.

[0043] refer to Figures 1 to 3In some embodiments, the sum of the thicknesses of the tab 120 and the adhesive 130 is equal to the thickness of the insulating coating 140. Specifically, along the thickness direction of the electrode, the sum of the thicknesses of the tab 120 and the adhesive 130 is equal to the thickness of the insulating coating 140. The surface of the insulating coating 140 facing away from the current collector 110 is on the same plane as the surface of the adhesive 130 facing away from the tab 120, and this plane can be flush with the surface of the active material layer 150 facing away from the current collector 110. Thus, the electrode surface is flatter, which is beneficial to make fuller use of the internal space of the electrochemical device and further improve the energy density of the electrochemical device.

[0044] refer to Figures 1 to 3 In some embodiments, the adhesive 130 projects along the thickness direction to cover the tab 120 within the receiving groove, so that the side of the tab 120 located within the receiving groove and facing away from the current collector 110 can be completely covered by the adhesive 130. This can prevent direct contact between the tab 120 and adjacent components, avoid short circuits caused by tiny burrs or protrusions on the surface of the tab 120 piercing the diaphragm, and prevent lithium plating around the tab 120, thus helping to improve the safety and cycle life of the electrode.

[0045] Specifically, when the adhesive 130 and the tab 120 are projected along the thickness direction of the electrode sheet, the projection area of ​​the adhesive 130 can completely cover the portion of the tab 120 located within the receiving groove. That is, within the receiving groove, the outer periphery of the adhesive 130 can be flush with the outer periphery of the tab 120 within the receiving groove. At this time, the projection boundary of the adhesive 130 coincides with the projection boundary of the tab 120. Alternatively, the outer periphery of the adhesive 130 can extend beyond the outer periphery of the tab 120 within the receiving groove, extending to the outside of the projection boundary of the tab 120. Both configurations achieve complete coverage of the portion of the tab 120 within the receiving groove by the adhesive 130. The insulating coating 140 is distributed around the outer periphery of the portion of the tab 120 within the receiving groove. The insulating coating 140 and the tab 120 do not overlap within the receiving groove, together forming a protective layer for the tab 120.

[0046] refer to Figures 1 to 3 In some embodiments, the tab 120 and the active material layer 150 are arranged at intervals, and the insulating coating 140 includes a first insulating portion 141 and a second insulating portion 142 connected together. Along the width direction, the first insulating part 141 is located between the tab 120 and the active material layer 150, and the sum of the dimensions of the first insulating part 141 and the adhesive 130 is equal to the dimension of the receiving groove. Along the length direction, the second insulating portion 142 is located between the tab 120 and the active material layer 150, and the sum of the dimensions of the second insulating portion 142 and the adhesive 130 is equal to the dimension of the receiving groove.

[0047] This allows the tab 120 to be isolated from the active material layer 150 by the insulating coating 140, effectively preventing the current around the tab 120 from coming into contact with the active material layer 150 and causing problems such as short circuits and lithium plating, which is beneficial to ensuring the cycle performance of the electrochemical device.

[0048] Specifically, along the width direction of the electrode (i.e., the length direction of the receiving groove), a first insulating portion 141 is located between the tab 120 and the active material layer 150, and the sum of the dimensions of the first insulating portion 141 and the adhesive 130 is equal to the dimension of the receiving groove along this direction. Along the length direction of the electrode (i.e., the width direction of the receiving groove), two second insulating portions 142 are located on both sides of the tab 120. One end of the first insulating portion 141 is connected to one of the second insulating portions 142, and the other end of the first insulating portion 141 is connected to the other second insulating portion 142. The sum of the dimensions of the two second insulating portions 142 and the adhesive 130 is equal to the dimension of the receiving groove along this direction. Thus, the tab 120 and the active material layer 150 are physically isolated by the insulating coating 140. Simultaneously, the displacement of the tab 120 within the receiving groove is further restricted, ensuring the stability of the connection between the tab 120 and the current collector 110, thereby guaranteeing the continuity of current transmission and improving the performance stability of the electrochemical device.

[0049] refer to Figures 1 to 3 This application provides an electrochemical device, including a positive electrode, a negative electrode, an electrolyte, and a separator, wherein the separator is located between the positive and negative electrodes, and the positive electrode used in the electrochemical device is the electrode described above. The electrochemical device can be any device that performs an electrochemical reaction to convert chemical energy into electrical energy, and specific non-limiting examples include all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries.

[0050] refer to Figures 1 to 3 This application provides an electronic device that includes the electrochemical device described above. The application of the electrochemical device is not particularly limited; it can be used in any electronic device known in the prior art. By employing the electrochemical device, the electronic device can be powered more stably, thus improving its battery life.

[0051] For example, electronic devices include, but are not limited to, mobile phones, smartphones, laptops, tablets, wearable devices, smartwatches, smart bracelets, smart glasses, power banks, televisions, game consoles, game controllers, digital cameras, smart speakers, headphones, keyboards, mice, monitors, drones, audio equipment, home appliances, toys, power tools, automobiles, motorcycles, electric bicycles, bicycles, robots, robot dogs, industrial robots, fitness robots, etc.

[0052] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. An electrode, characterized in that, include: A current collector, along its thickness direction, includes opposing first and second sides; An active material layer is disposed on at least one side of the current collector, and the active material layer and the current collector together enclose a receiving groove; The electrode tab is partially located in the receiving groove and is connected to the current collector. An adhesive element, located in the receiving groove, connects to and covers the side of the electrode tab opposite to the current collector; An insulating coating is located in the receiving groove, and the insulating coating is distributed around the outer periphery of the electrode tab.

2. The electrode sheet according to claim 1, characterized in that, The electrode includes a plurality of receiving grooves, including a first receiving groove and a second receiving groove. The active material layer is provided on both the first and second sides of the current collector. The first receiving groove is enclosed by the active material layer on the first side of the current collector and the active material layer on the same side. The second receiving groove is enclosed by the active material layer on the second side of the current collector and the active material layer on the same side. Both the first receiving groove and the second receiving groove contain the tab, the adhesive, and the insulating coating.

3. The electrode sheet according to claim 2, characterized in that, Along the thickness direction, the first receiving groove and the second receiving groove are symmetrically arranged on the first side and the second side.

4. The electrode sheet according to claim 3, characterized in that, Along the thickness direction, at least one of the tabs, the adhesive, and the insulating coating is symmetrically arranged on opposite sides of the current collector.

5. The electrode sheet according to claim 1, characterized in that, The sum of the thicknesses of the tab and the adhesive is less than or equal to the depth of the receiving groove, and the thickness of the insulating coating is less than or equal to the depth of the receiving groove.

6. The electrode sheet according to claim 5, characterized in that, The sum of the thicknesses of the tab and the adhesive is equal to the thickness of the insulating coating.

7. The electrode sheet according to claim 1, characterized in that, Within the receiving groove, the projection of the adhesive along the thickness direction covers the tab.

8. The electrode sheet according to claim 4, characterized in that, The tabs are arranged at intervals from the active material layer, and the insulating coating includes a first insulating portion and a second insulating portion connected together. Along the width direction, the first insulating portion is located between the tab and the active material layer, and the sum of the dimensions of the first insulating portion and the adhesive is equal to the dimension of the receiving groove; Along the length direction, the second insulating portion is located between the tab and the active material layer, and the sum of the dimensions of the second insulating portion and the adhesive is equal to the dimension of the receiving groove.

9. An electrochemical device, characterized in that, The electrode includes any one of claims 1 to 8.

10. An electronic device, characterized in that, Includes the electrochemical device as described in claim 9.

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