Pole piece and battery

Abstract

The utility model relates to battery technology field discloses a kind of pole piece and battery.The pole piece includes pole piece main body and multiple tabs connected to pole piece main body, wherein, pole piece main body and tab are arranged along first direction, multiple tabs are along second direction, first direction is perpendicular to second direction.Pole piece main body includes cutting edge away from tab side, the surface of cutting edge has first adhesive layer, first adhesive layer is covered on the surface of cutting edge along second direction and third direction, to make first adhesive layer cover burr projecting from cutting edge, third direction is the thickness direction of pole piece main body, third direction is perpendicular to first direction, and perpendicular to second direction.Along first direction, the size d1 μm of first adhesive layer projecting from cutting edge surface is 5 μm~100 μm, the size d2 mm of first adhesive layer in the part of the large surface of pole piece main body is less than or equal to 5 mm.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to an electrode and a battery. Background Technology

[0002] Current lithium-ion battery manufacturing processes generally fall into two categories: lamination and winding. The electrode production process typically includes four steps: coating, rolling, splitting, and die-cutting. Splitting involves dividing the electrode in half, while die-cutting cuts the electrode into equal-sized pieces. During splitting and die-cutting, burrs are easily generated in the cut surfaces. These burrs can puncture the separator during the subsequent winding of the positive electrode, separator, and negative electrode to assemble the battery, causing the positive and negative electrodes to come into contact and potentially short-circuit. Increased heat generation can also lead to thermal runaway, potentially resulting in battery fire or explosion, compromising battery safety. Utility Model Content

[0003] To address the safety concerns of existing batteries, this invention provides an electrode and battery that prevent burrs from piercing the separator, thereby improving battery safety.

[0004] In a first aspect, the present invention includes an electrode sheet, comprising an electrode sheet body and a plurality of electrode tabs connected to the electrode sheet body, wherein the electrode sheet body and the electrode tabs are arranged along a first direction, and the plurality of electrode tabs are arranged along a second direction, wherein the first direction is perpendicular to the second direction; The electrode body includes a cut edge on the side away from the tab. The surface of the cut edge has a first adhesive layer. The first adhesive layer covers the surface of the cut edge along the second direction and the third direction, so that the first adhesive layer covers the burrs protruding from the cut edge. The third direction is the thickness direction of the electrode body. The third direction is perpendicular to the first direction and perpendicular to the second direction. Along the first direction, the first adhesive layer protrudes from the cut edge surface by a dimension d1μm of 5μm to 100μm, and the first adhesive layer located on the large surface of the electrode body by a dimension d2 mm is less than or equal to 5mm.

[0005] Secondly, the present invention includes a battery comprising the electrode plates as described in the first aspect.

[0006] The above solution has the following beneficial effects: By forming a first adhesive layer on the surface of the cut edge, ensuring that the first adhesive layer completely covers the surface of the cut edge, and by controlling the size of the first adhesive layer in the first direction and its size on the main surface of the electrode body, it is possible to ensure that the first adhesive layer covers the burrs formed by the cut edge, preventing the burrs from protruding from the electrode surface. Subsequently, when the positive electrode, separator, and negative electrode are wound, the burrs will not pierce the separator, thus avoiding short circuits caused by contact between the positive and negative electrode sheets, thereby improving the battery's safety performance. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of an overall structure of the electrode sheet without the first adhesive layer in an embodiment of this utility model; Figure 2 This is a top view of an embodiment of the present invention where the electrode sheet is not coated with the first adhesive layer; Figure 3 This is a schematic diagram of an overall structure in which the electrode sheet is coated with a first adhesive layer in an embodiment of this utility model; Figure 4 This is a top view of the electrode sheet coated with a first adhesive layer in an embodiment of the present invention; Figure 5 This is a top view of the electrode sheet coated with a second adhesive layer in an embodiment of this utility model; Figure 6 This is a schematic diagram of the structure of a battery in one embodiment of the present invention; Figure 7 This is a cross-sectional structural diagram of a battery in an embodiment of this utility model; Figure 8 This is a schematic cross-sectional view of an electrode assembly in an embodiment of the present invention.

[0008] In the picture: 100-Electrode; 101-Cut edge; 110-Electrode body; 111-Current collector; 112-Active material layer; 120-Taper; 130-First adhesive layer; 140-Second adhesive layer; 100a-Positive electrode; 100b-Negative electrode; 200-Separator; 1000-Battery; 1100-Casing; 1200-Cover assembly; 1300-Electrode assembly. Detailed Implementation

[0009] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0010] refer to Figure 1 In this embodiment of the invention, the electrode 100 may include an electrode body 110 and a plurality of tabs 120 connected to the electrode body 110. The electrode body 110 and the tabs 120 are arranged along a first direction, and the plurality of tabs 120 are arranged along a second direction. Furthermore, if a third direction is defined as the thickness direction of the electrode body 110, then the first direction, the second direction, and the third direction are perpendicular to each other. The first direction can be considered as the width direction of the electrode 100, and the second direction can be considered as the length direction of the electrode 100.

[0011] In this embodiment, the electrode 100 can be a positive electrode or a negative electrode.

[0012] The positive electrode is one of the core components in a battery that carries the positive electrode active material. During charging, metal ions (such as lithium ions) are released from the crystal lattice of the positive electrode active material (oxidation reaction), migrate through the electrolyte, and intercalate into the negative electrode. During discharging, metal ions (such as lithium ions in a lithium battery) are released from the negative electrode and intercalated into the crystal lattice of the positive electrode active material (reduction reaction), thus realizing the storage and release of lithium ions.

[0013] A positive electrode generally includes a positive current collector and a positive active material layer. The positive active material layer is coated on at least one surface of the positive current collector and includes: a positive active material, a conductive agent, and a binder. The positive active material includes, but is not limited to, at least one of the following: lithium phosphates, lithium transition metal oxides and their respective modified compounds, or other conventional materials that can be used as positive active materials for batteries. These positive active materials can be used alone or in combination. The lithium phosphates include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also abbreviated 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. Lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also known as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25O2 (also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0014] The positive electrode conductive agent includes, but is not limited to, one or more combinations of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black, Super P, etc.), carbon nanotubes, graphene and carbon nanofibers.

[0015] The positive electrode binder includes, but is not limited to, one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, carboxymethyl chitosan, etc.

[0016] During battery charging, active ions (such as Li) from the positive electrode are embedded in the negative electrode, while electrons from the positive electrode are transferred to the negative electrode through an external circuit to maintain charge balance. During discharge, active ions (such as Li) previously embedded in the negative electrode can be released, while electrons from the negative electrode are transferred to the negative electrode through an external circuit to maintain charge balance, thus achieving energy storage and release.

[0017] The negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector. The negative electrode current collector is a conductive metal foil, which can be made of stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium with a silver-plated surface. The composite current collector may 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, copper, 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 negative electrode active layer includes a negative electrode active material, a conductive agent, and a binder.

[0018] The negative electrode active material can be carbon-based materials such as graphite, porous carbon, hard carbon, soft carbon, and mesophase carbon microspheres, or silicon-based materials such as elemental silicon, silicon oxides, silicon-carbon composites, and silicon-nitrogen composites. The conductive agent can be conductive carbon black, carbon nanotubes, etc., and the binder can be styrene-butadiene rubber, polyacrylic acid, etc.

[0019] The tab is located on one side of the positive / negative current collector and is formed separately from or integrally with the current collector. It is electrically connected to the current collector to conduct the current on the corresponding current collector. Generally, the tab can be made of a metal material with good conductivity (such as copper, aluminum, or nickel).

[0020] Combination Figure 1 and Figure 2 The electrode body 110 may include a current collector 111 and an active material layer 112 coated on two large surfaces of the current collector 111 arranged in a third direction.

[0021] refer to Figure 3 The electrode body 110 includes a cut edge 101 on the side away from the tab 120. Here, the cut edge 101 of the electrode body 110 is also the cut edge 101 of the current collector 111. The surface of the cut edge 101 has a first adhesive layer 130. The first adhesive layer 130 can cover the surface of the cut edge 101 along a second direction and a third direction, that is, the first adhesive layer 130 can completely cover the cut edge 101. Furthermore, along the first direction, the dimension d1μm of the first adhesive layer 130 protruding from the surface of the cut edge 101 is 5μm~100μm, and the dimension d2mm of the portion of the first adhesive layer 130 located on the large surface of the electrode body 110 is less than or equal to 5mm.

[0022] In specific implementation, the dimension d1μm of the first adhesive layer 130 protruding from the surface of the cut edge 101 can be 5μm, 8μm, 12μm, 16μm, 20μm, 25μm, 30μm, 35μm, 40μm, 50μm, 60μm, 65μm, 70μm, 75μm, 80μm, 90μm, 100μm, etc. The dimension d2 mm of the portion of the first adhesive layer 130 located on the large surface of the electrode body 110 can be 0.1mm, 0.25mm, 0.5mm, 0.7mm, 0.9mm, 1mm, 1.3mm, 1.6mm, 1.8mm, 2mm, 2.5mm, 2.8mm, 3.3mm, 3.8mm, 4.1mm, 4.5mm, 4.8mm, 5mm, etc.

[0023] It is understandable that after the electrode body 110 is cut, the side of the electrode body 110 away from the tab 120 is the cut edge, which is prone to burrs during the cutting process. By coating the surface of the cut edge 101 with a first adhesive layer 130, the first adhesive layer 130 can extend from the cut edge 101 to the large surface of the electrode body 110, ensuring that the first adhesive layer 130 completely covers the surface of the cut edge 101. Furthermore, by controlling the width of the first adhesive layer 130 to be relatively large, the first adhesive layer 130 can effectively seal the burrs generated. Subsequently, during the winding process of the electrode 100, because the burrs are covered by the first adhesive layer 130, they will not puncture the separator, thus ensuring the safety performance of the battery 1000.

[0024] Furthermore, the first adhesive layer 130 formed by the cut edge 101 can extend along the first direction to the large surface of the current collector 111, which can also ensure the adhesion effect between the first adhesive layer 130 and the cut edge 101, and the first adhesive layer 130 will not fall off from the cut edge 101.

[0025] In related technologies, adhesives are sometimes applied to the cross-section of the electrode to solve the burr problem. However, the adhesives currently used are usually water-based or oil-based. Water-based and oil-based adhesives not only have slow curing speeds and poor environmental resistance (water-based adhesives are prone to failure in humid environments, and oil-based adhesives tend to become sticky at high temperatures), but they are also difficult to recycle, leading to low production efficiency and high production costs.

[0026] In view of the problems existing in the existing adhesives, the first adhesive layer 130 in this embodiment can be one of the following: a photocurable first adhesive layer, a hot melt adhesive first adhesive layer, and a reactive first adhesive layer.

[0027] Understandably, when using a UV-curable adhesive to form the first adhesive layer 130, the fast curing speed of the UV-curable adhesive can effectively improve production efficiency. Furthermore, UV-curable adhesives contain almost no volatile organic compounds (VOCs), require no water or organic solvents as a carrier, and are environmentally friendly, posing no threat to the health of workers.

[0028] When a hot melt adhesive is used to form the first adhesive layer 130, the rapid curing speed of the hot melt adhesive effectively improves production efficiency. Furthermore, the hot melt adhesive can be remelted after heating, exhibiting strong reversibility, facilitating recycling, and reducing production costs.

[0029] When a reactive adhesive is used to form the first adhesive layer 130, the reactive adhesive has a wide temperature range, is solvent-resistant, and is resistant to aging, so it can maintain its state during long-term use of the battery, thereby ensuring the safety performance of the battery for a long time.

[0030] Furthermore, when the first adhesive layer 130 is formed on the surface of the cut edge 101, it can be achieved, for example, by coating, thereby making it easier to control the size of the first adhesive layer 130 and avoid the width of the first adhesive layer 130 being too large or too small.

[0031] In one optional embodiment, when the first adhesive layer 130 in this embodiment is a photocurable adhesive layer, the viscosity of the photocurable adhesive can be 500 mPa·s to 10000 mPa·s. The viscosity of the photocurable adhesive can be understood as its resistance to flow; a higher viscosity means weaker flowability. When the viscosity of the photocurable adhesive is in the range of 500 mPa·s to 10000 mPa·s, the viscosity is neither too high nor too low. When the photocurable adhesive is applied to the surface of the cut edge 101, it can prevent the adhesive from flowing too quickly and being wasted, while ensuring complete coating on the surface of the cut edge 101.

[0032] For example, the viscosity of the light-curing adhesive can be 500 mPa·s, 650 mPa·s, 800 mPa·s, 1000 mPa·s, 2000 mPa·s, 3000 mPa·s, 4000 mPa·s, 5000 mPa·s, 6000 mPa·s, 7000 mPa·s, 8000 mPa·s, 9000 mPa·s, 10000 mPa·s, etc.

[0033] The photocurable adhesive can be one of acrylic adhesives, polyurethane adhesives, or epoxy resin modified adhesives, thereby forming an acrylic adhesive layer, a polyurethane adhesive layer, or an epoxy resin modified adhesive layer on the surface of the cut edge 101. Since the current collector 111 is made of copper or aluminum, the above-mentioned adhesives have strong adhesion to metals and can be stably bonded to the surface of the cut edge 101, thereby preventing the first adhesive layer 130 from falling off the surface of the electrode 100 during repeated use of the battery, thus improving the battery's safety performance.

[0034] In this embodiment, the photocurable adhesive requires light to trigger a chemical reaction to complete the fixing and molding process. When forming the first adhesive layer 130 using the photocurable adhesive, after applying the photocurable adhesive to the surface of the cut edge 101, a UV lamp can be used to irradiate the surface of the cut edge 101, thereby allowing the photocurable adhesive to cure. For the photocurable adhesive in this embodiment, the curing time is less than or equal to 20 seconds. Therefore, when forming the first adhesive layer 130 using the photocurable adhesive in this embodiment, the curing time is very short, which can shorten the time of the electrode 100 in the adhesive coating and edge sealing process, thereby effectively improving production efficiency.

[0035] In one optional embodiment, when the first adhesive layer 130 in this embodiment is a hot melt adhesive layer, the viscosity of the hot melt adhesive can be between 500 mPa·s and 10000 mPa·s. It is understood that when the viscosity of the hot melt adhesive is in the range of 500 mPa·s to 10000 mPa·s, the viscosity is neither too high nor too low. When applied to the surface of the cut edge 101, it achieves both good adhesion and uniform coating, ensuring that the width of the first adhesive layer 130 is equal at all parts of the cut edge 101. This effectively seals the edge of the electrode 100, preventing burrs from piercing the diaphragm.

[0036] For example, the viscosity of hot melt adhesives can be 500 mPa·s, 650 mPa·s, 800 mPa·s, 1000 mPa·s, 2000 mPa·s, 3000 mPa·s, 4000 mPa·s, 5000 mPa·s, 6000 mPa·s, 7000 mPa·s, 8000 mPa·s, 9000 mPa·s, 10000 mPa·s, and so on.

[0037] Hot melt adhesives can be ethylene-vinyl acetate copolymer adhesives, polyolefin adhesives, polyurethane adhesives, styrene-butadiene-styrene block copolymer adhesives, or styrene-isoprene block copolymer adhesives, to form an ethylene-vinyl acetate copolymer adhesive layer, a polyolefin adhesive layer, a polyurethane adhesive layer, a styrene-butadiene-styrene block copolymer adhesive layer, or a styrene-isoprene block copolymer adhesive layer on the surface of the cut edge 101. Because hot melt adhesives have relatively high viscosity and maintain a certain degree of fluidity at high temperatures, they can ensure adhesion to the surface of the cut edge 101.

[0038] In this embodiment, the hot melt adhesive needs to be heated and melted before being applied to the surface of the cut edge 101, and then cooled and solidified. The cooling and solidification temperature can be room temperature, so environmental requirements are not high. After the hot melt adhesive is applied to the surface of the cut edge 101, the curing time of the hot melt adhesive is less than or equal to 1 minute. The short curing time can shorten the time of the electrode 100 in the adhesive coating and sealing process, thereby effectively improving production efficiency.

[0039] In one optional embodiment, when the first adhesive layer 130 in this embodiment is a reactive adhesive layer, the viscosity of the reactive adhesive can be between 500 mPa·s and 10000 mPa·s. It is understood that when the viscosity of the reactive adhesive is in the range of 500 mPa·s to 10000 mPa·s, the viscosity is neither too high nor too low. When applied to the surface of the cut edge 101, it achieves both good adhesion of the reactive adhesive and uniform coating, thereby ensuring that the width of the first adhesive layer 130 is equal at all parts of the cut edge 101. This effectively seals the edge of the electrode 100, preventing burrs from piercing the diaphragm 200.

[0040] For example, the viscosity of the reactive adhesive layer can be 500 mPa·s, 650 mPa·s, 800 mPa·s, 1000 mPa·s, 2000 mPa·s, 3000 mPa·s, 4000 mPa·s, 5000 mPa·s, 6000 mPa·s, 7000 mPa·s, 8000 mPa·s, 9000 mPa·s, 10000 mPa·s, etc.

[0041] The reactive adhesive can be one of a reactive polyurethane adhesive, a reactive epoxy resin adhesive, or a reactive phenolic resin adhesive, to form a reactive polyurethane adhesive layer, a reactive epoxy resin adhesive layer, or a reactive phenolic resin adhesive layer on the surface of the cut edge 101. Because reactive adhesives have relatively high viscosity and maintain a certain degree of fluidity at high temperatures, they can ensure adhesion to the surface of the cut edge 101.

[0042] In this implementation scheme, for example, for reactive phenolic resin adhesives, heating is required during the curing process. The heating temperature can be controlled according to the desired viscosity to meet different production needs. When the reactive adhesive is coated on the surface of the cut edge 101, the curing time of the reactive adhesive is less than or equal to 10 minutes. This short curing time reduces the time required for the electrode 100 in the adhesive coating and sealing process, thereby effectively improving production efficiency.

[0043] In the above embodiments, the first adhesive layer 130 is one of a photocurable adhesive layer, a hot melt adhesive layer, and a reactive adhesive layer, and is only used as an example. In practical applications, the first adhesive layer 130 can also be an adhesive layer structure formed by other adhesives. In this case, the viscosity of the adhesive forming the corresponding first adhesive layer 130 can be controlled at 500 mPa·s to 10000 mPa·s to ensure the quality of the first adhesive layer 130 coated on the surface of the cut edge 101.

[0044] In some embodiments, continue to refer to Figure 3When the first adhesive layer 130 is formed on the surface of the cut edge 101, the dimension d3μm of the first adhesive layer 130 along the third direction can be 50μm~500μm, that is, the thickness of the first adhesive layer 130 is 50μm~500μm. Since the burrs of the cut edge 101 may protrude from the surface of the current collector 111 along the thickness direction, when the thickness of the first adhesive layer 130 is controlled within the range of 50μm~500μm, the thickness of the first adhesive layer 130 is relatively large. In this way, it can be ensured that the first adhesive layer 130 completely covers the cut edge 101 in the thickness direction and covers the burrs protruding from the surface of the current collector 111, thereby protecting the safety of the battery.

[0045] For example, the dimension d3μm of the first adhesive layer 130 along a third direction can be 50μm, 60μm, 75μm, 90μm, 100μm, 120μm, 135μm, 150μm, 170μm, 185μm, 200μm, 220μm, 250μm, 280μm, 300μm, 325μm, 350μm, 380μm, 400μm, 430μm, 470μm, 500μm, etc.

[0046] As an optional implementation, the dimension d3μm of the first adhesive layer 130 along the third direction can be 150μm~350μm. This ensures that the first adhesive layer 130 can completely cover the burrs, and also ensures that the thickness of the electrode 100 at the part of the first adhesive layer 130 is not too large, thus preventing uneven thickness of the electrode 100 during the winding process.

[0047] In this embodiment, the dimension d3μm of the first adhesive layer 130 along a third direction can be, for example, 150μm, 160μm, 175μm, 180μm, 200μm, 215μm, 240μm, 250μm, 270μm, 280μm, 300μm, 315μm, 330μm, 350μm, etc.

[0048] In some embodiments, reference Figure 3 and Figure 4 When adhesive is applied to the cut edge 101, the adhesive has a certain fluidity. A portion of the adhesive flows to the large surface of the current collector 111, so that the part of the large surface of the current collector 111 close to the cut edge 101 also forms the first adhesive layer 130. This ensures that the cut edge 101 can be safely covered by the first adhesive layer 130.

[0049] As mentioned above, the large surface of the current collector 111 is coated with an active material layer 112. In practical applications, along the first direction, there is a gap between the active material layer 112 and the portion of the first adhesive layer 130 located on the large surface, or the first adhesive layer 130 may also cover a portion of the active material layer 112.

[0050] Since the coating area of ​​the active material layer 112 varies among different electrode models 100, when the distance between the active material layer 112 and the cut edge 101 is large, a certain distance can be maintained between the first adhesive layer 130 and the active material layer 112 to isolate them from each other. Since the active material layer 112 is the core functional layer for energy storage and conversion in the battery, by isolating the first adhesive layer 130 from the active material layer 112, the first adhesive layer 130 will not cover the active material layer 112 during its formation, thereby ensuring the battery's charge and discharge performance.

[0051] When the gap between the active material layer 112 and the cut edge 101 is small, the first adhesive layer 130 can cover a portion of the active material layer 112, thereby ensuring that the area of ​​the first adhesive layer 130 on the large surface is sufficient, thus ensuring the coverage effect of burrs.

[0052] Based on this, the dimension d2 mm of the portion of the first adhesive layer 130 located on the large surface of the current collector 111 in the first direction can be 0.5 mm to 1.5 mm. Specifically, the dimension d2 mm of the portion of the first adhesive layer 130 located on the large surface of the current collector 111 in the first direction can be 0.5 mm, 0.6 mm, 0.75 mm, 0.8 mm, 0.9 mm, 1 mm, 1.15 mm, 1.25 mm, 1.35 mm, 1.5 mm, etc.

[0053] In some embodiments, reference Figure 5 The electrode body 110 may also be provided with a second adhesive layer 140 on each of its two sides along the second direction, and the second adhesive layer 140 may cover the corresponding side. Since the sides of the electrode body 110 are also cut, by covering the two sides of the electrode body 110 with the second adhesive layer 140, the burrs on the two sides of the electrode body 110 can be covered by the second adhesive layer 140, thereby preventing the burrs from puncturing the diaphragm.

[0054] The thickness and other parameters of the second adhesive layer 140 can be designed according to actual needs, as long as the second adhesive layer 140 can completely cover the burrs on the side. For example, the dimension d4μm of the second adhesive layer 140 protruding from the side along the second direction can be 5 μm to 100 μm. Specifically, d4μm can be 5μm, 8μm, 12μm, 16μm, 20μm, 25μm, 30μm, 35μm, 40μm, 50μm, 60μm, 65μm, 70μm, 75μm, 80μm, 90μm, 100μm, etc.

[0055] In some embodiments, when applying adhesive to the cut edge 101 to form a first adhesive layer 130 or forming a second adhesive layer 140 on the side of the electrode body 110, the process can be performed, for example, by dispensing. This allows for precise control of the size of the adhesive layer 130 or the second adhesive layer 140, thereby ensuring that the formed first adhesive layer 130 or the second adhesive layer 140 meets production requirements.

[0056] Taking the first adhesive layer 130 as an example, when applying adhesive to the cut edge 101 by dispensing, a dispensing device can be used, which is placed on one side of the cut edge 101 of the electrode 100. Keeping the dispensing device stationary, the electrode 100 is driven to move along the second direction, allowing different parts of the electrode 100 to pass through the dispensing device. The dispensing speed of the dispensing device remains uniform, and the electrode 100 maintains a stable moving speed. This ensures that the amount of adhesive applied to each part of the cut edge 101 of the electrode 100 is the same, thus forming a first adhesive layer 130 with uniform width and thickness on the cut edge 101.

[0057] In other embodiments, when applying adhesive to the cut edge 101 to form the first adhesive layer 130, a dip-coating method can also be used. This method allows the cut edge 101 of the electrode 100 to be immersed in the adhesive, thereby enabling rapid application of adhesive to the surface of the cut edge 101 and improving work efficiency. Furthermore, the dip-coating method also ensures that the width and thickness of the first adhesive layer 130 formed on the surface of the cut edge 101 are uniform, thus guaranteeing the sealing effect of the electrode 100.

[0058] For example, when the adhesive is applied to the cut edge 101 of the electrode 100 by dip coating, a container with an open top can be provided, the interior of which is filled with adhesive. The electrode 100 is driven to move from top to bottom toward the container, thereby causing the electrode 100 to extend into the container through the opening, and the cut edge 101 of the electrode 100 is immersed in the adhesive, such that the surface of the cut edge 101 is covered with adhesive.

[0059] In this embodiment, the electrode 100 moves along a first direction to move closer to or further away from the container. At this time, the height of the electrode 100 immersed in the adhesive can be controlled by controlling the moving speed of the electrode 100, thereby controlling the area occupied by the first adhesive layer 130 on the large surface of the current collector 111.

[0060] As an optional implementation, when coating the cut edge 101 of the electrode 100 with an acrylic UV-curable adhesive with a viscosity of 2000 mPa·s, the cut edge 101 of the electrode 100 can be immersed in the acrylic UV-curable adhesive by dip coating. Then, after curing by UV lamp irradiation, the electrode 100 with the cut edge 101 sealed is obtained by winding. At this time, the dimension of the first adhesive layer 130 along the first direction (width of the first adhesive layer 130) is 20 μm, the dimension along the third direction (thickness of the first adhesive layer 130) is 320 μm, and the dimension of the first adhesive layer 130 located on the large surface of the current collector 111 along the first direction is 1 mm. In this way, the formed electrode 100 can ensure a good sealing effect. Subsequently, the electrode 100 and the separator 200 are wound together to form an electrode assembly 1300. After the electrode assembly 1300 is assembled to form a battery, the resulting battery product can avoid short circuits caused by the burrs of the electrode 100 piercing the separator 200, thereby ensuring the safety performance of the battery 1000.

[0061] It should be noted that the electrode 100 in this embodiment can be either a positive electrode or a negative electrode, and this embodiment does not limit it.

[0062] Based on the same design concept, referencing Figures 6 to 8 This utility model embodiment can also provide a battery 1000, which may include a housing 1100, a cover assembly 1200, and two sets of electrode assemblies 1300. The housing 1100 has an opening at the top, the cover assembly 1200 covers the opening of the housing 1100, and both sets of electrode assemblies 1300 are disposed inside the housing 1100.

[0063] Battery 1000 can store chemical energy and controllably convert chemical energy into electrical energy. In recyclable batteries, the active materials can be activated by charging after discharge so that the battery can continue to be used.

[0064] Each electrode assembly 1300 may include a positive electrode 100a, a negative electrode 100b, and a separator 200. The separator 200 is located between the positive electrode 100a and the negative electrode 100b to isolate them and prevent short circuits caused by contact. The positive electrode 100a, separator 200, and negative electrode 100b can be simultaneously wound to form the electrode assembly 1300 in a wound state. Here, both the positive electrode 100a and the negative electrode 100b can be the electrode 100 described in the foregoing embodiments.

[0065] For the positive electrode 100a, it includes a plurality of positive electrode tabs 120, which are stacked in the thickness direction of the electrode assembly 1300 after the positive electrode 100a is wound. Similarly, the negative electrode 100b includes a plurality of negative electrode tabs 120, which are stacked in the thickness direction of the electrode assembly after the negative electrode 100b is wound.

[0066] Two sets of electrode assemblies 1300 are stacked inside the housing 1100. The cover plate assembly 1200 has an adapter plate on the side facing the inside of the housing 1100. When the electrode assembly 1300 is placed inside the housing 1100, the positive electrode tab 120 and the negative electrode tab 120 are both located on the side of the electrode assembly 1300 facing the cover plate assembly 1200 and are respectively welded to the adapter plate.

[0067] Compared to traditional electrodes and batteries, the electrode 100 in this embodiment of the invention has a first adhesive layer 130 formed on the surface of the cut edge 101, which is formed by cutting the electrode body 110 away from the tab 120. The first adhesive layer 130 completely covers the cut edge 101, which can seal the burrs generated by cutting the cut edge 101 and prevent the burrs from protruding from the surface of the electrode 100. After the electrode 100 is subsequently wound with the separator 200 to assemble the battery 1000, the burrs on the electrode 100 will not pierce the separator 200. This can prevent the positive electrode 100a and the negative electrode 100b on both sides of the separator 200 from contacting, thereby preventing the battery 1000 from short-circuiting, preventing the battery 1000 from catching fire and exploding, and effectively improving the safety performance of the battery 1000.

[0068] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this utility model without departing from the spirit and scope of this utility model. Therefore, if these modifications and variations of this utility model fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. An electrode sheet, characterized in that, It includes an electrode body and a plurality of tabs connected to the electrode body, wherein the electrode body and the tabs are arranged along a first direction, and the plurality of tabs are arranged along a second direction, wherein the first direction is perpendicular to the second direction; The electrode body includes a cut edge on the side away from the tab. The surface of the cut edge has a first adhesive layer. The first adhesive layer covers the surface of the cut edge along the second direction and the third direction, so that the first adhesive layer covers the burrs protruding from the cut edge. The third direction is the thickness direction of the electrode body. The third direction is perpendicular to the first direction and perpendicular to the second direction. Along the first direction, the first adhesive layer protrudes from the cut edge surface by a dimension d1μm of 5μm to 100μm, and the first adhesive layer located on the large surface of the electrode body by a dimension d2 mm is less than or equal to 5 mm.

2. The electrode sheet according to claim 1, characterized in that, The first adhesive layer is one of a photocurable first adhesive layer, a hot melt adhesive first adhesive layer, and a reactive first adhesive layer.

3. The electrode sheet according to claim 1, characterized in that, The electrode body includes a current collector and an active material layer coated on two large surfaces of the current collector arranged along the third direction. The first adhesive layer extends along the first direction to the portion of the large surface near the cut edge.

4. The electrode sheet according to claim 3, characterized in that, Along the first direction, there is a gap between the active material layer and the portion of the first adhesive layer located on the large surface, or the first adhesive layer covers a portion of the active material layer.

5. The electrode sheet according to claim 4, characterized in that, The dimension d2 mm of the portion of the first adhesive layer located on the large surface along the first direction is 0.5 mm to 1.5 mm.

6. The electrode sheet according to claim 1, characterized in that, The dimension d3μm of the first adhesive layer along the third direction is 50μm~500μm.

7. The electrode sheet according to claim 6, characterized in that, The dimension d3μm of the first adhesive layer along the third direction is 150μm~350μm.

8. The electrode sheet according to claim 1, characterized in that, The viscosity of the adhesive that forms the first adhesive layer is 500 mPa·s to 10000 mPa·s.

9. The electrode sheet according to claim 1, characterized in that, The electrode body has a second adhesive layer on each of its two sides along the second direction, and the second adhesive layer covers the sides.

10. A battery, characterized in that, Including the electrode as described in any one of claims 1 to 9.

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