Pole piece, electrochemical device, and electronic device

Abstract

The application discloses a pole piece, an electrochemical device and an electronic device, comprising: a main body part and a transition part. The main body part comprises two large faces opposite in a first direction, and a peripheral surface located between and intersecting with the two large faces, the peripheral surface comprises intersecting first and second side surfaces, the first and second side surfaces define a concave corner region, the included angle between the first and second side surfaces is, and the first direction is the thickness direction of the pole piece; the transition part is located in the corner region and connected to the first and second side surfaces, the transition part has a transition surface, the transition surface is a smooth surface and smoothly connected to the first and second side surfaces. Thus, the curvature discontinuity of the pole piece in the corner region is reduced. Therefore, when the pole piece is stacked to form a special-shaped battery cell, a transition unit can be formed in the corner space of the special-shaped battery cell, the curvature discontinuity of the special-shaped battery cell at the corner is reduced, and the wetting effect of the active material near the corner region is improved.

Description

Technical Field

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

[0002] Irregularly shaped battery cells are created by shaping the battery cell into an irregular form based on the traditional stacking process, in order to better adapt to the irregular spaces inside the terminal device. However, irregularly shaped battery cells with corners, such as L-shaped cells, tend to spread along a straight surface due to the abrupt curvature change at the corners. This makes it easy for dead zones to form in the electrolyte flow at the corners, resulting in insufficient wetting of the active material near the corners. Consequently, the gas generated in this area during the formation stage cannot be effectively replaced and discharged, forming a bubble retention zone. The retained gas hinders further electrolyte wetting, which not only increases the impedance of the electrochemical device but also reduces its service life. Utility Model Content

[0003] This application aims to at least solve one of the technical problems existing in the prior art. To this end, this application proposes an electrode that can be used to form an electrochemical device, reducing the curvature abrupt change at the corner of the cell inside the electrochemical device, thereby improving the wetting effect of the active material at the corner, reducing the internal resistance of the electrochemical device, and extending the service life of the electrochemical device.

[0004] This application also provides an electrochemical device including the above-described electrode.

[0005] This application also provides an electronic device including the above-described electrochemical device.

[0006] The electrode sheet according to a first aspect embodiment of this application includes: a main body portion and a transition portion.

[0007] The main body includes two large surfaces facing away from each other in a first direction, and a peripheral surface located between and intersecting the two large surfaces. The peripheral surface includes an intersecting first side surface and a second side surface. The first side surface and the second side surface define a concave corner area. The included angle between the first side surface and the second side surface is θ. The first direction is the thickness direction of the electrode sheet. The transition portion is located in the corner area and connects to the first side surface and the second side surface. The transition portion has a transition surface, which is a smooth surface and is smoothly connected to the first side surface and the second side surface.

[0008] The electrode sheet according to the embodiments of this application has at least the following beneficial effects: In this embodiment, the electrode includes a transition portion located in the corner region. The transition surface of the transition portion is a smooth surface and is smoothly connected to the first and second side surfaces forming the corner region, thereby reducing the abrupt curvature change of the electrode in the corner region. Therefore, when the electrodes are stacked to form a non-circular battery cell, a transition unit can be formed in the corner space of the non-circular battery cell, thereby reducing the abrupt curvature change of the non-circular battery cell at the corner, and thus improving the electrolyte wetting effect of the active material near the corner region, thereby reducing the internal resistance of the electrochemical device and extending the service life of the electrochemical device.

[0009] According to some embodiments of this application, the transition surface is an arc surface and is tangent to the first side surface and the second side surface.

[0010] According to some embodiments of this application, the main body includes a main current collector and a main active material layer, the main active material layer being located on at least one side of the main current collector in the first direction, and the transition portion includes a sub-current collector and a sub-active material layer, the sub-current collector being connected to the main current collector, and the sub-active material layer being located on at least one side of the sub-current collector in the first direction. The sub-active material layer has a gas guide groove that extends to the transition surface.

[0011] According to some embodiments of this application, the roughness of the inner wall surface of the air guide groove is Ra1, and the roughness of the surface of the sub-active material layer facing away from the sub-collector is Ra2, where Ra1≤Ra2.

[0012] According to some embodiments of this application, the air guide groove is formed by embossing on the sub-active material layer.

[0013] According to some embodiments of this application, the inner wall surface of the air guide groove is further provided with a hydrophobic layer, which has a porous structure.

[0014] An electrochemical device according to a second aspect of this application includes: a housing and a battery cell. The housing has a receiving cavity. The battery cell includes a separator and a plurality of electrodes as described in the first aspect embodiment. The plurality of electrodes includes a first electrode and a second electrode with opposite polarities. The first electrode and the second electrode are alternately stacked. The separator is located between the first electrode and the second electrode. Each first side and each second side together form a corner space. Each transition portion is stacked to form a transition unit located in the corner space.

[0015] The electrochemical device according to the embodiments of this application has at least the following beneficial effects: The electrode sheet of the first aspect embodiment is stacked to form a transition unit located in the corner space, thereby reducing the curvature change of the irregularly shaped cell at the corner, thereby improving the electrolyte wetting effect of the active material near the corner area, so as to reduce the internal resistance of the electrochemical device and improve the service life of the electrochemical device of this embodiment.

[0016] According to some embodiments of this application, the main body includes a main current collector and a main active material layer, the main active material layer being located on at least one side of the main current collector in the first direction, and the transition portion includes a sub-current collector and a sub-active material layer, the sub-current collector being connected to the main current collector, and the sub-active material layer being located on at least one side of the sub-current collector in the first direction. The sub-active material layer has a gas guide groove that extends to the transition surface and forms an opening on the transition surface. The outer shell has an exhaust reservation position for setting an exhaust structure during the electrochemical device formation stage. The opening faces the exhaust reservation position.

[0017] According to some embodiments of this application, the air guide groove disposed on the first electrode is defined as the first air guide groove, and the air guide groove disposed on the second electrode is defined as the second air guide groove, and the first air guide groove and the second air guide groove are alternately disposed.

[0018] An electronic device according to a third aspect of this application includes an electrochemical device according to a second aspect of this application.

[0019] The electronic device according to the embodiments of this application has at least the following beneficial effects: The electrochemical device of the second aspect embodiment has a transition unit in the corner space of the battery cell inside the electrochemical device, thereby reducing the curvature change of the irregularly shaped battery cell at the corner, thereby improving the electrolyte wetting effect of the active material near the corner area, so as to reduce the internal resistance of the electrochemical device and improve the service life of the electrochemical device, thereby improving the service life of the electronic device of this embodiment.

[0020] 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

[0021] 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 according to the first aspect of this application; Figure 2 for Figure 1 A structural diagram from another perspective; Figure 3This is a schematic diagram of the structure of another electrode sheet according to the first aspect of this application; Figure 4 for Figure 3 A magnified view of a portion of region A in the middle; Figure 5 This is a schematic diagram of the structure of the battery cell in the electrochemical device according to the second aspect of this application; Figure 6 for Figure 5 A magnified view of a portion of region B in the middle.

[0022] Figure label: Current collector 10; Active material layer 20, main active material layer 21, sub-active material layer 22; gas guide groove 2201, first gas guide groove 2211, second gas guide groove 2221; Main body 100, large surface 110, peripheral surface 120, first side surface 121, second side surface 122; Transition section 200, transition surface 210; Corner area 300; First electrode 1000, second electrode 2000, transition unit 3000, corner space 4000. Detailed Implementation

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] Definitions: Smooth surface: A surface without sharp points, creases, edges, or abrupt changes.

[0028] Irregularly shaped battery cells are created by shaping the battery cell into an irregular form based on the traditional stacking process, in order to better adapt to the irregular spaces inside the terminal device. However, irregularly shaped battery cells with corners, such as L-shaped cells, tend to spread along a straight surface due to the abrupt curvature change at the corners. This makes it easy for dead zones to form in the electrolyte flow at the corners, resulting in insufficient wetting of the active material near the corners. Consequently, the gas generated in this area during the formation stage cannot be effectively replaced and discharged, forming a bubble retention zone. The retained gas hinders further electrolyte wetting, which not only increases the impedance of the electrochemical device but also reduces its service life.

[0029] In view of the above background, this application proposes an electrode that can be used to form an electrochemical device, reduce the curvature abrupt change at the corner of the cell inside the electrochemical device, thereby improving the wetting effect of the active material at the corner, reducing the internal resistance of the electrochemical device, and extending the service life of the electrochemical device.

[0030] Combination Figures 1 to 6 In explaining this application, the center line in the figure should not be interpreted as the actual outline of the electrode, but is only used to show the position of the transition section 200 more clearly.

[0031] Please refer to the details. Figures 1 to 3In this embodiment, the electrode is, for example, a cathode or an anode. When the electrode is a cathode, the cathode includes a current collector 10 and an active material layer 20 coated on the surface of the current collector 10. The current collector 10 can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, or titanium, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). The active material layer 20 is formed by coating and rolling a positive electrode active material, which includes one or more of lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials of batteries can also be used. These positive electrode active materials can be used alone or in combination of two or more. Examples of lithium phosphates include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4, also known as LFP), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.1 5Al0.05 At least one of O2 and its modified compounds.

[0032] When the electrode is an anode, the current collector 10 can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, or titanium, etc. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). The active material layer 20 is formed by coating and rolling a negative electrode active material, which can be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0033] The electrode includes a main body 100 and a transition portion 200 (e.g., composed of a current collector 10 and an active material layer 20). Figure 1 and Figure 3 The main body 100 includes two large surfaces 110 in a first direction and a peripheral surface 120 located between and intersecting the two large surfaces 110. For example, if both sides of the electrode have active material layers 20, then the large surface 110 is the surface of the active material facing away from the current collector 10, and the peripheral surface 120 is jointly formed by the side surfaces of the two active material layers 20 and the side surface of the current collector 10; when the electrode has an active material layer 20 on only one side (such as the electrode located on the outermost layer of a laminated cell), one large surface 110 is the surface of the current collector 10 facing away from the active material, and another large surface 110 is the surface of the active material layer 20 facing away from the current collector 10, and the peripheral surface 120 is jointly formed by the side surface of one active material layer 20 and the side surface of one current collector 10.

[0034] Circumferential surface 120 includes intersecting first side surface 121 and second side surface 122 (e.g. Figure 2As shown, the first side surface 121 and the second side surface 122 define a concave corner area 300. For example, if the electrode has an L-shaped structure, the peripheral surface 120 includes only one first side surface 121 and one second side surface 122. The included angle between the first side surface 121 and the second side surface 122 is 90° to form a right-angled corner area 300. However, this is not a limitation. Depending on the electronic device to be installed, the electrode may have two, three, or four corner areas 300, and the included angle between the first side surface 121 and the second side surface 122 is not limited to 90°; it may also be 60°, 70°, 80°, 100°, 110°, or 120°, etc. A transition portion 200 is located in the corner area 300 and connects to the first side surface 121 and the second side surface 122. The transition portion 200 has a transition surface 210, which is a smooth surface and smoothly connects to the first side surface 121 and the second side surface 122. For example, the transition surface 210 is a smooth curved surface such as an arc surface, parabolic surface, or elliptical surface. Taking an arc surface as an example, the arc surface is tangentially connected to the first side surface 121 and the second side surface 122, respectively. The transition surface 210 can also be composed of a flat surface and arc surfaces located on both sides of the flat surface. The two arc surfaces are tangentially connected to the flat surface and tangentially connected to the first side surface 121 and the second side surface 122, respectively, to ensure that the curvature of the corner area 300 changes continuously and avoids abrupt curvature changes, as long as the transition surface 210 has no stepped protrusions or sharp edges. Therefore, when stacking electrode sheets to form a shaped battery cell, a transition unit 3000 can be formed within the corner space 4000 of the shaped battery cell, thereby reducing the curvature abrupt change of the shaped battery cell at the corner, and thus improving the electrolyte wetting effect of the active material near the corner area 300, thereby reducing the internal resistance of the electrochemical device and improving the service life of the electrochemical device.

[0035] Reference Figure 3 and Figure 4In some embodiments, the main body 100 includes a main current collector and a main active material layer 21, the main active material layer 21 being located on at least one side of the main current collector in a first direction. The transition portion 200 includes a sub-current collector and a sub-active material layer 22, the sub-current collector being connected to the main current collector, and the sub-active material layer 22 being located on at least one side of the sub-current collector in the first direction. The current collector 10 includes a main current collector and a sub-current collector, and the active material layer 20 includes a main active material layer 21 and a sub-active material layer 22. The sub-active material layer 22 has a gas guide groove 2201, which can be, for example, a straight groove or a curved groove. Depending on the area of ​​the transition portion 200, the number of gas guide grooves 2201 can be one, two, three, or four, to ensure the coverage area of ​​the gas guide grooves 2201. The gas guide grooves 2201 extend along the transition surface 210 to form an opening on the transition surface 210. On the one hand, the gas guide groove 2201 can provide an additional permeation channel for the electrolyte. That is, after the electrochemical device is injected with electrolyte, the electrolyte can quickly diffuse into the interior of the sub-active material layer 22 through the gas guide groove 2201, effectively improving the wetting effect of the sub-active material layer. On the other hand, the bubbles generated during the electrochemical device formation stage (the process of activating the electrode active material) and the circulation process can be directly discharged to the outside of the transition surface 210 through the gas guide groove 2201, reducing the accumulation of bubbles in the corner area 300 to form "gas resistance", reducing the resistance of bubbles to electrolyte wetting, thereby improving the wetting effect of the active material in the corner area 300, ensuring that the active material in the corner area 300 is always in a good electrochemical reaction state, reducing the internal resistance of the electrochemical device, and improving the service life of the electrochemical device.

[0036] Based on the above embodiments, the inner wall surface of the air guide groove 2201 is a smooth surface. For example, the cross-section of the air guide groove 2201 is semi-circular, arc-shaped or U-shaped, without sharp edges, so that the bubbles can flow evenly along the smooth surface.

[0037] In some embodiments, the roughness of the inner wall surface of the gas guide groove 2201 is Ra1, and the roughness of the surface of the current collector 10 on the back side of the sub-active material layer 22 is Ra2, where Ra1 ≤ Ra2. Specifically, bubbles are easily trapped on rough surfaces due to capillary adsorption. Based on this, this embodiment makes the inner wall surface roughness of the gas guide groove 2201 even lower to improve the smoothness of the inner wall surface of the gas guide groove 2201, thereby reducing the adhesion between the bubbles and the wall surface, reducing the flow resistance of the bubbles, and making it easier for the bubbles to be discharged along the gas guide groove 2201. This further reduces the accumulation of bubbles in the corner area 300 to form "gas resistance", thereby reducing the obstruction of the bubbles to the electrolyte wetting, and thus improving the wetting effect of the active material in the corner area 300. This ensures that the active material in the corner area 300 is always in a good electrochemical reaction state, reduces the internal resistance of the electrochemical device, and improves the service life of the electrochemical device. Meanwhile, the smoother inner wall of the air guide groove 2201 can effectively guide the electrolyte to quickly penetrate the active material in the corner area 300 along the groove, further shortening the wetting path and time.

[0038] Based on the above embodiments, the gas guide groove 2201 is formed by embossing on the sub-active material layer 22. Specifically, the embossed sub-active material layer 22 only changes the surface morphology of the sub-active material layer 22 without removing or damaging the active material, so as to ensure the energy density of the electrode. On the other hand, the inner wall surface of the embossed gas guide groove 2201 is uniformly smooth, requiring no additional polishing treatment, which makes the structure processing of this embodiment simpler and reduces processing costs.

[0039] It should be noted that embossing is a common processing method in the present invention and is not considered as an innovative point of this application.

[0040] In some embodiments, the inner wall surface of the gas guide groove 2201 is further provided with a hydrophobic layer, which has a porous structure. The hydrophobic layer is made of one or more of polytetrafluoroethylene (PTFE), perfluorooctyltriethoxysilane (FAS-13), and polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP). The hydrophobicity reduces the adhesion between bubbles and the wall surface, making it easier for bubbles to flow along the gas guide groove 2201. This, in turn, makes it easier to remove bubbles from the corner region 300, reducing bubble aggregation and thus reducing the resistance of bubbles to electrolyte wetting, improving the wetting effect of the active material in the corner region 300. The porous structure of the hydrophobic layer allows lithium ions to pass through, thereby reducing the internal resistance of the electrochemical device.

[0041] Reference Figure 5 and Figure 6The electrochemical device of the second aspect embodiment includes any device in which an electrochemical reaction occurs to interconvert chemical energy and electrical energy. 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. The electrochemical device includes a casing and a battery cell. The casing is, for example, an aluminum casing, a steel casing, or a soft-shell membrane, and has a receiving cavity. The battery cell includes a separator and multiple electrodes, among which a first electrode 1000 and a second electrode 2000 of opposite polarities are included; that is, if the first electrode 1000 is the anode, then the second electrode 2000 is the cathode, and vice versa. Figure 5 As shown in the example, the first electrode 1000 and the second electrode 2000 are alternately stacked. The first electrode 1000 is the cathode (dashed line portion), and the second electrode 2000 is the anode. The edge of the second electrode 2000 protrudes beyond the edge of the first electrode 1000 to improve lithium plating. A separator is located between the first electrode 1000 and the second electrode 2000. Each first side 121 and each second side 122 together form a corner space 4000. Each transition portion 200 is stacked to form a transition unit 3000 located in the corner space 4000, thereby eliminating the curvature abrupt change of the cell at the corner, thereby improving the wetting effect of the active material near the corner, reducing the internal resistance of the electrochemical device, and extending the service life of the electrochemical device in this embodiment.

[0042] It should be noted that since the electrochemical device of this embodiment adopts all the technical features of the electrode of the first aspect embodiment, the electrochemical device of this embodiment has all the beneficial effects brought by the first aspect embodiment, which will not be repeated here.

[0043] In some embodiments, the main body 100 includes a main current collector and a main active material layer 21, the main active material layer 21 being located on at least one side of the main current collector in a first direction. The transition portion 200 includes a sub-current collector and a sub-active material layer 22, the sub-current collector being connected to the main current collector, and the sub-active material layer 22 being located on at least one side of the sub-current collector in the first direction. The sub-active material layer 22 has a gas guide groove 2201 extending to a transition surface 210 and forming an opening on the transition surface 210. The outer casing has a venting pre-reservation position, which is used to set up a venting structure during the electrochemical device formation stage, with the opening facing the venting pre-reservation position. Exemplarily, the outer casing is a steel shell, and the venting pre-reservation position is provided with a vent hole, with the opening facing the vent hole; or the outer casing is a soft film such as an aluminum-plastic film, and the venting pre-reservation position is provided with a gas bag to contain the gas generated during the formation process. Finally, the gas bag is removed and the remaining portion is sealed to ensure that no gas accumulates inside the battery cell.

[0044] Specifically, during venting, the air guide groove 2201 allows bubbles to flow more easily to the vent hole without having to meander inside the cell, making it easier to remove the bubbles and reducing the amount of bubbles remaining inside the cell. This further reduces the obstruction of bubbles to electrolyte wetting, ensuring that the active material in the corner space 4000 is fully wetted, thereby reducing the internal resistance of the electrochemical device and improving the service life of the electrochemical device in this embodiment.

[0045] In some embodiments, the gas guide groove 2201 disposed on the first electrode 1000 is defined as the first gas guide groove 2211, and the gas guide groove 2201 disposed on the second electrode 2000 is defined as the second gas guide groove 2221. The first gas guide groove 2211 and the second gas guide groove 2221 are staggered. For example, the included angle between the extending directions of the first gas guide groove 2211 and the second gas guide groove 2221 is 30°, 45°, or 60°, or within the range of any two of the above values. The staggered gas guide grooves 2201 form a cross-flow guiding network, thereby increasing the gas guiding range, effectively avoiding the "exhaust blind zone" caused by a single-direction gas guide groove 2201, thereby improving exhaust efficiency, further reducing the accumulation of bubbles in the corner area 300, and ensuring uniform wetting effect of the electrolyte on the active material.

[0046] The electronic device of the third aspect embodiment of this application is not particularly limited to any electronic device known in the prior art, including but 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, and android robots. The electronic device includes the electrochemical device of the third aspect embodiment. The corner space 4000 of the battery cell inside the electrochemical device has a transition unit 3000, thereby reducing the curvature abrupt change of the irregularly shaped battery cell at the corner, and thus improving the wetting effect of the active material in the corner space 4000, thereby reducing the internal resistance of the electrochemical device and increasing its service life, thereby improving the service life of the electronic device of this embodiment.

[0047] It should be noted that since the electronic device of this embodiment adopts all the technical features of the electrochemical device of the second aspect embodiment, the electronic device of this embodiment has all the beneficial effects brought by the second aspect embodiment, which will not be repeated here.

[0048] 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, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of this application. Furthermore, in the description of this application, the reference to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., means that the 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. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

Claims

1. An electrode, characterized in that, include: The main body includes two large surfaces facing away from each other in a first direction, and a peripheral surface located between the two large surfaces and intersecting the two large surfaces. The peripheral surface includes an intersecting first side surface and a second side surface, the first side surface and the second side surface defining a concave corner area. The first direction is the thickness direction of the electrode sheet. A transition portion is located in the corner area and connects the first side and the second side. The transition portion has a transition surface, which is a smooth surface and is smoothly connected to the first side and the second side.

2. The electrode sheet according to claim 1, characterized in that, The transition surface is an arc surface and is tangent to the first side surface and the second side surface.

3. The electrode sheet according to claim 1, characterized in that, The main body includes a main current collector and a main active material layer, the main active material layer being located on at least one side of the main current collector in the first direction; the transition part includes a sub-current collector and a sub-active material layer, the sub-current collector being connected to the main current collector, and the sub-active material layer being located on at least one side of the sub-current collector in the first direction. The sub-active material layer has a gas guide groove that extends to the transition surface.

4. The electrode sheet according to claim 3, characterized in that, The roughness of the inner wall of the air guide groove is Ra1, and the roughness of the surface of the sub-active material layer facing away from the sub-collector is Ra2, where Ra1≤Ra2.

5. The electrode sheet according to claim 4, characterized in that, The air guide groove is formed by embossing on the sub-active material layer.

6. The electrode sheet according to claim 3, characterized in that, The inner wall of the air guide groove is also provided with a hydrophobic layer, which has a porous structure.

7. An electrochemical device, characterized in that, include: The outer shell has a receiving cavity; A battery cell includes a separator and a plurality of electrodes as described in any one of claims 1 to 6, wherein the plurality of electrodes include a first electrode and a second electrode with opposite polarities, the first electrode and the second electrode are alternately stacked, the separator is located between the first electrode and the second electrode, each of the first side and each of the second side together constitute a corner space, and each of the transition portions is stacked to form a transition unit located in the corner space.

8. The electrochemical device according to claim 7, characterized in that, The main body includes a main current collector and a main active material layer, the main active material layer being located on at least one side of the main current collector in the first direction; the transition part includes a sub-current collector and a sub-active material layer, the sub-current collector being connected to the main current collector, and the sub-active material layer being located on at least one side of the sub-current collector in the first direction. The sub-active material layer has a gas guide groove that extends to the transition surface and forms an opening on the transition surface. The outer shell has an exhaust reservation position for setting an exhaust structure during the electrochemical device formation stage. The opening faces the exhaust reservation position.

9. The electrochemical device according to claim 8, characterized in that, The air guide groove disposed on the first electrode is defined as the first air guide groove, and the air guide groove disposed on the second electrode is defined as the second air guide groove, and the first air guide groove and the second air guide groove are alternately disposed.

10. An electronic device, characterized in that, The electrochemical device includes any one of claims 7 to 9.

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