Tab anti-tearing method, tab, electrode assembly and battery

Abstract

The invention provides an anti-tearing method of a tab, the tab, an electrode assembly and a battery, and the anti-tearing method of the tab comprises the following steps: arranging an adhesive material on a welding part of the tab to form a buffer piece which at least partially covers the tab; the adhesive material is arranged at the welding part where the tab is easy to tear to form the buffer part, and the buffer part at least partially covers the welding part, so that the tab is prevented from being torn at the welding part, and the reject ratio of tab tearing is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and particularly to a method for preventing ear tabs from tearing, an ear tab, an electrode assembly, and a battery. Background Art

[0002] In related technologies, the phenomenon of ear tab tearing is common in the battery production process, mainly manifested as the tearing of one to multiple layers at the proximal end of the ear tab. The tearing of the ear tab will affect the electrical performance and safety performance of the battery.

[0003] Therefore, in related technologies, there is a technical problem that the ear tab is prone to tearing, which affects the electrical performance and safety performance of the battery. Summary of the Invention

[0004] Embodiments of the present invention provide a method for preventing ear tabs from tearing, an ear tab, an electrode assembly, and a battery, which can improve the technical problem that the ear tab in the prior art is prone to tearing and affects the electrical performance and safety performance of the battery.

[0005] In a first aspect, embodiments of the present invention provide a method for preventing ear tabs from tearing, including:

[0006] Providing an adhesive material on the welding part of the ear tab to form a buffer member that at least partially covers the welding part.

[0007] In one embodiment, the volume of the adhesive liquid of the adhesive material is a, the unit of a is milliliter, the surface area of the welding part is b, the unit of b is square millimeter, the surface tension of the adhesive material is c, the unit of c is millinewton per meter, the viscosity of the adhesive liquid of the adhesive material is d, the unit of d is millipascal·second, and the value range of the correlation coefficient k is 15 to 20, where a = (b×k) / (c×d).

[0008] In one embodiment, the range of the volume of the adhesive liquid of the adhesive material is 0.05 milliliter to 0.3 milliliter, and / or, the range of the surface area of the welding part is 60 square millimeters to 96 square millimeters, and / or, the range of the surface tension of the adhesive material is 30 millinewtons per meter to 40 millinewtons per meter, and / or, the range of the viscosity of the adhesive liquid of the adhesive material is 200 millipascal·seconds to 500 millipascal·seconds.

[0009] In one embodiment, the adhesive material is any one of acrylic glue, modified epoxy acrylic structural glue, cyan-red acrylic ab glue, and acrylate structural glue.

[0010] In a second aspect, embodiments of the present invention provide an ear tab, on which a welding part is formed, and the ear tab is provided with a buffer member that at least partially covers the welding part.

[0011] Among them, the welding part of the ear tab is used to weld with a connecting piece, and both ends of the connecting piece are respectively connected to the core package and the top cover assembly to form an electric current loop.

[0012] In one embodiment, the tensile shear strength of the buffer ranges from 10 MPa to 30 MPa.

[0013] In one embodiment, along the thickness direction of the tab, the thickness of the buffer ranges from 0.5 mm to 3.5 mm.

[0014] In one embodiment, the ratio between the contact area of the buffer and the welding part and the surface area of the welding part ranges from 0.8 to 1.5.

[0015] In one embodiment, the buffer is a glue material, and the glue material is any one of acrylic glue, modified epoxy acrylic structural glue, blue-red acrylic ab glue, and acrylate structural glue.

[0016] In a third aspect, an embodiment of the present invention provides an electrode assembly, including the tab as described in any of the above embodiments.

[0017] In a fourth aspect, an embodiment of the present invention provides a battery, including the tab as described in any of the above embodiments, or the electrode assembly as described in the above embodiments.

[0018] Beneficial effects of the embodiments of the present invention:

[0019] In the embodiments of the present invention, by providing a glue material at the welding part where the tab is prone to tearing to form a buffer for preventing the tab from tearing, and the buffer at least partially covers the welding part, thereby preventing the tab from tearing at the welding part position and reducing the defect rate of tab tearing. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 It is a schematic structural diagram of a pole piece provided by an embodiment of the present invention before forming a welding part;

[0022] Figure 2 It is a schematic structural diagram of a pole piece provided by an embodiment of the present invention after forming a welding part;

[0023] Figure 3 It is a schematic structural diagram of a pole piece provided by an embodiment of the present invention;

[0024] Figure 4 It is a schematic structural diagram of a tab provided by an embodiment of the present invention. Detailed implementation manners

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention. In addition, it should be understood that the specific implementation manners described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In the present invention, unless otherwise stated, the orientation words such as "upper" and "lower" generally refer to the upper and lower in the actual use or working state of the device, specifically the drawing direction in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0026] In addition, the terms "first", "second" and similar words do not denote any order, quantity or importance, but are only used to distinguish different technical features. The term "a plurality of" and similar words mean two or more, unless otherwise clearly defined.

[0027] Please refer to Figures 1 to 4 , the anti-tearing method of the tab provided by the embodiment of the present invention includes: arranging a glue material on the welding part 2 of the tab 1 to form a buffer member 3 that at least partially covers the welding part 2.

[0028] In this embodiment, by arranging a glue material at the welding part 2 of the tab 1 where tearing is likely to occur, a buffer member 3 for preventing the tab 1 from tearing is formed. The buffer member 3 at least partially covers the welding part 2, thereby preventing the tab 1 from tearing at the position of the welding part 2, reducing the defective rate of the tab 1 tearing, and alleviating the technical problem that the tab 1 in the related art is prone to tearing and affects the electrical performance and safety performance of the battery.

[0029] The technical solutions of the present application will be described below in combination with specific embodiments.

[0030] It should be noted that the proximal end of the tab 1 refers to the end of the tab 1 close to the electrode tab 4 or the core package, which is the part in direct contact with the ultrasonic welding head.

[0031] In one embodiment, please refer to Figure 1 and Figure 2 , by forming a welding part 2 on the tab 1, the welding part 2 includes a plurality of welding marks, and the welding of multiple layers of tabs 1 and the welding of multiple layers of tabs 1 and the connecting piece are realized through the welding part 2.

[0032] It can be understood that Figure 1 the tab 1 in Figure 2The figure in the middle is a schematic diagram of welding the tab 1 by means of an ultrasonic welding head. Among them, when a welding part 2 is formed on the tab 1, multiple layers of tabs 1 are welded and attached at the position of the welding part 2, and a concave structure is formed.

[0033] Among them, the concave structure refers to: Figure 2 The circular pit within the dashed box in the figure. This pit is the weld mark formed by the downward pressure of the ultrasonic welding head. It can be understood that by using welding heads with different numbers and shapes, pits with different numbers and shapes will be obtained. The pits are used to realize the welding of the welding part 2 of the tab 1 and the connecting piece.

[0034] Among them, when the ultrasonic welding head presses down on the tab to form a weld mark, the tab 1 is welded to the connecting piece on one side at the weld mark. After the welding is completed, a buffer member 3 covering at least part of the welding part 2 is formed on the other side of the tab 1, so that during the movement of the tab 1, the tab 1 is prevented from being torn due to the large stress at the weld mark position.

[0035] Among them, the welding part 2 is Figure 2 The area within the dashed box in the figure. Compared with other parts of the tab 1, the above-mentioned concave structure is also formed on the welding part 2, that is, the surface of the welding part 2 is uneven.

[0036] It can be understood that since there are multiple concave structures in the welding part 2, when the ultrasonic welding head presses down to form the concave structure, the welding part 2 can also be made to sink as a whole.

[0037] It should be noted that at the concave structure, relatively large stress is likely to be generated, resulting in tearing of the welding part 2 at this position. Therefore, please refer to Figure 3 . By forming a buffer member 3 on the surface of the welding part 2, the stress received by the welding part 2 at the concave structure is reduced by using the buffer member 3, thereby reducing the occurrence of tearing of the welding part 2.

[0038] In one embodiment, the buffer member 3 is formed on the welding part 2 by means of a glue coating process. The volume of the glue liquid of the glue material is a, and the unit of a is milliliter. The surface area of the welding part 2 is b, and the unit of b is square millimeter. The surface tension of the glue material is c, and the unit of c is millinewton per meter. The viscosity of the glue liquid of the glue material is d, and the unit of d is millipascal·second. The value range of the correlation coefficient k is 15 to 20, where a = (b×k) / (c×d).

[0039] Among them, the specific value of k can be but is not limited to 15, 17, 19, 20.

[0040] It can be understood that the unit of k is used to balance the units on both sides of the equation so that the numerical values and units on both sides of the equation are the same.

[0041] It is understandable that by making the adhesive material satisfy a = (b × k) / (c × d), the tearing defect rate of the tab 1 can be further reduced.

[0042] In some embodiments, the buffer member 3 can also be formed on the welding portion 2 by adhesion.

[0043] In one embodiment, the range of the volume of the adhesive liquid of the adhesive material is 0.05 ml to 0.3 ml, the surface area of the welding portion 2 is in the range of 60 square millimeters to 96 square millimeters, the surface tension of the adhesive material is in the range of 30 mN / m to 40 mN / m, and the viscosity of the adhesive liquid of the adhesive material is in the range of 200 mPa·s to 500 mPa·s.

[0044] Among them, the volume of the adhesive liquid of the adhesive material can specifically but not limitedly be 0.05, 0.13, 0.28, 0.30.

[0045] Among them, the surface area of the welding portion 2 can specifically but not limitedly be 60 square millimeters, 64 square millimeters, 80 square millimeters, 96 square millimeters.

[0046] Among them, the surface tension of the adhesive material can specifically but not limitedly be 30 mN / m, 33 mN / m, 36 mN / m, 40 mN / m.

[0047] Among them, the viscosity of the adhesive liquid of the adhesive material can specifically but not limitedly be 200 mPa·s, 300 mPa·s, 100 mPa·s, 500 mPa·s.

[0048] Among them, this application provides three groups of embodiments and one group of comparative examples, as shown in the following table:

[0049]

[0050] Among them, cell numbers one, two, and three respectively correspond to Embodiment 1, Embodiment 2, Embodiment 3, and Comparative Example 1. Embodiment 1, Embodiment 2, and Embodiment 3 all satisfy the ranges of the volume of the adhesive liquid of the adhesive material, the surface area of the welding portion 2, the surface tension of the adhesive material, and the viscosity of the adhesive liquid of the adhesive material.

[0051] In some embodiments, the tensile shear strength of the buffer member 3 ranges from 10 MPa to 30 MPa.

[0052] In some embodiments, along the thickness direction of the tab 1, the thickness of the buffer member 3 ranges from 0.5 mm to 3.5 mm.

[0053] In some embodiments, the ratio between the contact area of the buffer member 3 and the welding portion 2 and the surface area of the welding portion 2 ranges from 0.8 to 1.5.

[0054] In some embodiments, the adhesive material is any one of acrylic adhesives, modified epoxy acrylic structural adhesives, blue-red acrylic AB adhesives, and acrylate structural adhesives.

[0055] Among them, for Embodiment 1: The volume a of the adhesive liquid of the adhesive material is 0.30 milliliters, the weld mark area b of the welded part 2 is 96 square millimeters, the surface tension c of the adhesive material is 30 millinewtons per meter, and the viscosity d of the adhesive liquid of the adhesive material is 200 millipascal·seconds; at this time, a = (b × k) / (c × d) is satisfied, and the defective rate of the tearing of the tab 1 using the adhesive material in Embodiment 1 is 500 ppm.

[0056] Among them, for Embodiment 2: The volume a of the adhesive liquid of the adhesive material is 0.13 milliliters, the weld mark area b of the welded part 2 is 80 square millimeters, the surface tension c of the adhesive material is 33 millinewtons per meter, and the viscosity d of the adhesive liquid of the adhesive material is 300 millipascal·seconds; at this time, a = (b × k) / (c × d) is satisfied, and the defective rate of the tearing of the tab 1 using the adhesive material in Embodiment 2 is 300 ppm.

[0057] It should be noted that when the viscosity is less than 200 millipascal·seconds, it is difficult for the adhesive material to flow and be positioned. After coating, the adhesive material is prone to flowing, difficult to stay at the position where bonding is required, likely to cause uneven distribution of the adhesive material, affecting the bonding effect, not conducive to precisely controlling the position of the adhesive material, and bringing inconvenience to the operation; when the viscosity is greater than 500 millipascal·seconds, the excessive viscosity makes it difficult to evenly coat the adhesive material, and a greater pressure and force are required to push the adhesive material away, which not only increases the operation difficulty but also may result in uneven coating thickness of the adhesive material, affecting the overall bonding effect.

[0058] Among them, when the viscosity is less than 200 millipascal·seconds, it will cause an insufficient thickness and strength of the adhesive layer to be formed on the tab surface, and the adhesive material cannot fully fill the pits on the tab surface. After curing, the effective contact area and intermolecular force between the adhesive layer and the tab are small, resulting in a reduction in bonding strength and easy occurrence of degumming.

[0059] Among them, when the viscosity is greater than 500 millipascal·seconds, it will also lead to poor wettability. The adhesive material is difficult to fully wet the tab surface and cannot fit well with the surface of the adherend, and voids or bubbles will be formed between the adhesive layer and the tab. These defects will weaken the adhesion between the adhesive material and the tab and reduce the reliability of the bonding.

[0060] Among them, when the viscosity is greater than 500 millipascal·seconds, the excessive viscosity will hinder the chemical reaction inside the adhesive material, slow down the curing process, and prolong the overall curing time. For large-scale production, it will reduce the production efficiency.

[0061] Among them, when the viscosity is greater than 500 mPa·s, high-viscosity adhesive materials may generate relatively large internal stresses during the curing process. When the internal stress exceeds a certain limit, it may cause the adhesive layer to crack by itself, or stress concentration may occur at the interface between the tab and the adhesive layer, thereby reducing the bonding strength. Especially for the bonding of tabs, such internal stresses may damage the tabs.

[0062] It should be noted that when the surface tension is greater than 40 mN / m, there will be problems such as poor wetting, bubble residue, and edge shrinkage, which are specifically as follows:

[0063] Poor wetting: The adhesive material is difficult to spread on the surface of the tab, forming water droplet-like shapes and unable to fully cover and wet the surface of the tab, resulting in a reduced contact area between the adhesive material and the tab and a deteriorated bonding effect.

[0064] Bubble residue: During the coating process of the adhesive material, due to the large surface tension, air bubbles are difficult to discharge and easily remain in the adhesive layer. These bubbles will become weak points in the adhesive layer, reducing the strength and density of the adhesive layer and affecting the bonding performance of the adhesive material.

[0065] Edge shrinkage: During the curing process of the adhesive material, the large surface tension will cause the adhesive material to shrink towards the center, resulting in a thinning of the edge of the adhesive layer or even a lack of adhesive, affecting the integrity and reliability of the bonding.

[0066] It should be noted that when the surface tension is less than 30 mN / m, it is difficult to form a stable adhesive layer due to the too small surface tension: During the curing process, due to the small surface tension, the adhesive material cannot well maintain its shape and position, is prone to deformation and displacement, and is difficult to form a uniform and stable adhesive layer, thereby affecting the bonding effect and the performance of the adhesive layer; and the adsorption of dust and other impurities is enhanced: The adhesive material with a small surface tension has a higher surface energy and is more likely to adsorb dust, impurities, etc. in the surrounding environment. These impurities mixed into the adhesive layer will reduce the purity and performance of the adhesive material, affecting the bonding strength and durability.

[0067] For Example 3: The volume a of the adhesive liquid of the adhesive material is 0.05 mL, the weld mark area b of the welding part 2 is 60 mm², the surface tension c of the adhesive material is 40 mN / m, and the viscosity d of the adhesive liquid of the adhesive material is 500 mPa·s; at this time, a = (b×k) / (c×d) is satisfied, and the tearing failure rate of the tab 1 using the adhesive material in Example 3 is 500 ppm.

[0068] For Comparative Example 1: The volume a of the adhesive liquid of the adhesive material is 0.28 mL, the weld mark area b of the welding part 2 is 64 mm², the surface tension c of the adhesive material is 36 mN / m, and the viscosity d of the adhesive liquid of the adhesive material is 100 mPa·s; at this time, a = (b×k) / (c×d) is not satisfied, and the tearing failure rate of the tab 1 using the adhesive material in Comparative Example 1 is 1000 ppm.

[0069] It can be understood that the cell serial numbers one, two, and three are three groups of embodiments respectively, and the cell serial number four is a comparative example. Among them, the three groups of embodiments of Example 1, Example 2, and Example 3 satisfy the above formula a = (b×k) / (c×d), which can reduce the defective rate of the tearing of tab 1 to 500 ppm; while the comparative example one does not satisfy the above formula a = (b×k) / (c×d). Compared with Example 1, Example 2, and Example 3, the defective rate of the tearing of tab 1 is 1000 ppm, which is significantly higher than that of Example 1, Example 2, and Example 3 that satisfy the above formula a = (b×k) / (c×d).

[0070] In this embodiment, the range of the volume of the glue liquid of the glue material is 0.05 ml to 0.3 ml, the range of the surface area of the welding part 2 is 60 square millimeters to 96 square millimeters, the range of the surface tension of the glue material is 30 mN / m to 40 mN / m, and the range of the viscosity of the glue liquid of the glue material is 200 mPa·s to 500 mPa·s; and it satisfies a = (b×k) / (c×d), so that the defective rate of the tearing of tab 1 is reduced to less than or equal to 500 ppm.

[0071] In one embodiment, the glue material is any one of acrylic glue, modified epoxy acrylic structural glue, cyan-red acrylic ab glue, and acrylic ester structural glue.

[0072] Among them, the glue material includes monomer structure, cross-linking agent, initiator, plasticizer, and solvent.

[0073] Among them, the monomer structure includes at least one of acrylate monomer, methyl acrylate, ethyl acrylate, and butyl acrylate; the monomer structure is the main component of the glue material, and the monomer structure accounts for 60% to 80% of the total mass of the glue material.

[0074] Among them, the cross-linking agent includes divinylbenzene or trimethylolpropane triacrylate. The cross-linking agent is used to form a three-dimensional network structure to enhance the cohesion and stability of the glue material. The cross-linking agent accounts for 3% to 10% of the total mass of the glue material.

[0075] Among them, the initiator includes at least one of benzoyl peroxide or azobisisobutyronitrile, which initiates the polymerization reaction of the monomer structure. The initiator accounts for 0.5% to 2% of the total mass of the glue material.

[0076] Among them, the plasticizer includes at least one of dibutyl phthalate or triphenyl phosphate, which can increase the flexibility of the glue material and improve the operability of the glue material. The plasticizer accounts for 5% to 15% of the total mass of the glue material.

[0077] Among them, the solvent includes at least one of ethyl acetate, toluene, and acetone, which is used to adjust the viscosity of the glue material. The solvent accounts for 10% to 30% of the total mass of the glue material.

[0078] It is understandable that selecting any one of the above-mentioned adhesives as acrylic adhesive, modified epoxy acrylic structural adhesive, blue-red acrylic AB adhesive, or acrylate structural adhesive can achieve good adhesion and polymerization performance.

[0079] This application also provides a preparation method for the adhesive. Taking the acrylic adhesive as an example for illustration, when the adhesive is of other adhesive structures, the steps are the same. The specific steps are as follows:

[0080] The first step: Prepare a reaction vessel;

[0081] Specifically, select a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser as the reaction vessel. It should be noted that before use, the reaction vessel can be cleaned and dried to ensure its cleanliness and dryness, and to ensure that no impurities affect the reaction;

[0082] The second step: Carry out the polymerization reaction;

[0083] First, perform pre-mixing; add accurately weighed acrylate monomers, cross-linking agents, plasticizers, and initiators into the three-necked flask, turn on the stirrer, and stir at a speed of 200 r / min to 300 r / min for 15 minutes to 30 minutes to fully mix all the raw materials evenly.

[0084] Secondly, carry out heating polymerization; place the three-necked flask in a constant temperature water bath or oil bath, and slowly heat up to 70 to 90 °C. During the heating process, the initiator decomposes to generate free radicals, which initiate the polymerization reaction of acrylate monomers. Keep the temperature and stirring speed unchanged, and react for 3 hours to 6 hours, and observe the viscosity change of the reaction system;

[0085] Finally, adjust the viscosity; after the reaction is completed, add an appropriate amount of solvent to adjust the viscosity according to the actual viscosity of the adhesive. If the viscosity is high, slowly drop the solvent and continue stirring until the viscosity reaches 200 to 500 millipascal-seconds; it should be noted that during the addition of the solvent, stir evenly to avoid too large local viscosity differences;

[0086] The third step: Carry out post-treatment;

[0087] First, carry out degassing; since bubbles may be generated during the reaction process, which will affect the quality and use performance of the adhesive, degassing treatment is required; place the reacted adhesive in a vacuum environment for a period of time, for example, place it at a vacuum degree of 0.08 MPa to 0.1 MPa for 30 minutes to 60 minutes to allow the bubbles to escape;

[0088] Secondly, carry out filtration; use a filter screen or filter cloth to filter the adhesive to remove any unreacted solid particles or impurities that may exist in the adhesive to obtain a pure adhesive;

[0089] Finally, perform packaging and storage; put the prepared adhesive material into a well-sealed container, and mark information such as the name, composition, preparation date, and shelf life of the adhesive material on the container. It should be noted that during storage, the container containing the adhesive material needs to be placed in a cool, dry, and well-ventilated place to avoid direct sunlight and high-temperature environments that may cause the adhesive material to fail.

[0090] In a second aspect, please refer to Figures 1 to 3 , an embodiment of the present invention provides an electrode assembly, including a pole piece 4 and a tab 1. The tab 1 can be integrally extended from the pole piece 4 or independently arranged with the pole piece 4 and then formed by a connection method such as welding. A welding portion 2 is formed on the tab 1, and a buffer member 3 is provided on the tab 1 to at least partially cover the welding portion 2.

[0091] Among them, the welding portion 2 of the tab 1 is used for welding with a connection piece, and both ends of the connection piece are respectively connected to a core package and a top cover assembly to form a current loop.

[0092] Among them, the connection between the connection piece and the welding portion 2 of the tab 1 is first achieved by a welding mark. During the transportation of the tab 1 and the connection piece, there is a defect that the stress at the welding mark position of the tab 1 is large and it is easy to tear. Therefore, in this application, after the tab 1 and the connection piece are welded, a buffer member 3 is formed on the welding portion 2, and the buffer member 3 plays an effect of buffering the stress at the welding mark position to prevent the welding portion of the tab from tearing.

[0093] Among them, the pole piece 4 can be a positive pole piece or a negative pole piece.

[0094] Among them, the core package includes a plurality of the above-mentioned electrode assemblies. More specifically, it includes a positive pole piece, a negative pole piece, and a separator located between the positive pole piece and the negative pole piece.

[0095] Among them, the positive pole piece and the negative pole piece are arranged at intervals periodically.

[0096] Among them, the top cover assembly is used to jointly surround the core package with the housing. The housing covers the side and bottom surfaces of the core package, and the top cover assembly is used to cover the top surface of the core package. The top cover assembly is connected to the connection piece and is used to electrically connect the current of the core package to an external circuit through the top cover assembly.

[0097] It can be understood that the welding portion 2 is the position where the tab 1 contacts the ultrasonic welding head. Since the welding portion 2 is prone to tearing, a buffer member 3 is provided on the surface of the welding portion 2 so that the buffer member 3 at least partially covers the welding portion 2, thereby preventing the tab 1 from tearing and reducing the defect rate of tab tearing.

[0098] In one embodiment, the tensile shear strength range of the buffer member 3 is from 10 MPa to 30 MPa.

[0099] Among them, the tensile shear strength of the buffer member 3 can be any one of 10 MPa, 15 MPa, 20 MPa, 25 MPa, and 30 MPa.

[0100] It can be understood that the tensile shear strength range of the buffer member 3 is 10 MPa to 30 MPa, so that the buffer member 3 can better reduce the defective rate of the tearing of the tab 1.

[0101] In one embodiment, in the thickness direction of the electrode tab 4, that is, in the thickness direction of the tab 1, the thickness range of the buffer member 3 is 0.5 mm to 3.5 mm.

[0102] Among them, the thickness of the buffer member 3 can be any one of 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, and 3.5 mm.

[0103] It can be understood that when the thickness of the buffer member 3 is less than 0.5 mm, the anti-tearing effect of the buffer member 3 on the tab 1 in the electrode tab 4 is poor; when the thickness of the buffer member 3 is greater than 3.5 mm, during the subsequent process of attaching the insulating glue to the tab 1, the thickness of the buffer member 3 will affect the fitting effect of the insulating glue at the buffer member 3. At the same time, it will also increase the probability of short circuit between the positive and negative electrodes of the battery.

[0104] In one embodiment, the ratio range of the contact area between the buffer member 3 and the welding part 2 to the surface area of the welding part 2 is 0.8 to 1.5.

[0105] Among them, the ratio of the contact area between the buffer member 3 and the welding part 2 to the surface area of the welding part 2 can be any one of 0.8, 1, 1.2, 1.3, and 1.5.

[0106] It can be understood that when the ratio of the contact area between the buffer member 3 and the welding part 2 to the surface area of the welding part 2 is less than 0.8, the anti-tearing effect of the buffer member 3 on the tab 1 in the electrode tab 4 is poor; when the ratio of the contact area between the buffer member 3 and the welding part 2 to the surface area of the welding part 2 is greater than 1.5, during the subsequent process of attaching the insulating glue to the tab 1, it will affect the fitting effect of the insulating glue at the buffer member 3. At the same time, it will also increase the probability of short circuit between the positive and negative electrodes of the battery.

[0107] In one embodiment, the surface area range of the welding part 2 is 30 square millimeters to 100 square millimeters.

[0108] Among them, the surface area of the welding part 2 is Figure 3 the surface area of the tab 1 within the range of the dashed line frame in

[0109] Among them, the surface area of the welding part 2 can be any one of 30 square millimeters, 50 square millimeters, 70 square millimeters, 90 square millimeters, and 100 square millimeters.

[0110] It can be understood that when the surface area of the welding part 2 is less than 30 square millimeters, the surface area of the welding part 2 is too small, which will affect the conduction of the current in the battery and cause the battery to overheat; when the surface area of the welding part 2 is greater than 100 square millimeters, the surface area of the welding part 2 is too large, which will affect the bonding effect of the insulating glue at the buffer part 3 during the subsequent process of pasting the insulating glue on the tab 1. At the same time, it will also increase the probability of short circuit between the positive and negative electrodes of the battery.

[0111] In one embodiment, in the thickness direction of the tab 1, the buffer part 3 and the welding part 2 are arranged in coincidence.

[0112] It can be understood that by arranging the buffer part 3 and the welding part 2 in coincidence, when the volume and size of the buffer part 3 are small, the welding part 2 of the tab 1 can be better protected, so that the welding part 2 is not easily torn, and the defective rate of tab 1 tearing is reduced.

[0113] In one embodiment, the buffer part 3 is a glue material, and the glue material is any one of acrylic glue, modified epoxy acrylic structural glue, cyan red acrylic ab glue, and acrylic ester structural glue.

[0114] Among them, the glue material includes a monomer structure, a crosslinking agent, an initiator, a plasticizer, and a solvent.

[0115] Among them, the monomer structure includes at least one of acrylate monomer, methyl acrylate, ethyl acrylate, and butyl acrylate; the monomer structure is the main component of the glue material, and the monomer structure accounts for 60% to 80% of the total mass of the glue material.

[0116] Among them, the crosslinking agent includes divinylbenzene or trimethylolpropane triacrylate. The crosslinking agent is used to form a three-dimensional network structure to enhance the cohesion and stability of the glue material, and the crosslinking agent accounts for 3% to 10% of the total mass of the glue material.

[0117] Among them, the initiator includes at least one of benzoyl peroxide or azobisisobutyronitrile, which initiates the polymerization reaction of the monomer structure, and the initiator accounts for 0.5% to 2% of the total mass of the glue material.

[0118] Among them, the plasticizer includes at least one of dibutyl phthalate or triphenyl phosphate, which can increase the flexibility of the glue material and improve the operability of the glue material, and the plasticizer accounts for 5% to 15% of the total mass of the glue material.

[0119] Among them, the solvent includes at least one of ethyl acetate, toluene, and acetone, which is used to adjust the viscosity of the glue material, and the solvent accounts for 10% to 30% of the total mass of the glue material.

[0120] It can be understood that selecting any one of the above-mentioned adhesives as acrylic adhesive, modified epoxy acrylic structural adhesive, blue-red acrylic AB adhesive, or acrylate structural adhesive can achieve good adhesion and polymerization performance.

[0121] In a third aspect, an embodiment of the present invention provides an electrode assembly, including the electrode sheet 4 as described in any one of the above embodiments.

[0122] In a fourth aspect, an embodiment of the present invention provides a battery, including the electrode sheet 4 as described in any one of the above embodiments, or the electrode tab 1, or the electrode assembly as described in the above embodiments.

[0123] The present invention provides a method for preventing the electrode tab 1 from tearing. By setting an adhesive at the welding part 2 of the electrode tab 1 to form a buffer member 3, the buffer member 3 acts on the welding part 2, avoiding the tearing of the welding part 2 and reducing the defective rate of the tearing of the electrode tab 1.

[0124] The above has introduced the embodiments of the present invention in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for preventing a tab (1) from tearing, characterized in that: include: A glue material is provided on the welding portion (2) of the pole lug (1) to form a buffer member (3) that at least partially covers the welding portion (2).

2. The method for preventing the tab (1) from tearing according to claim 1, characterized in that: The volume of the adhesive liquid of the adhesive material is a, the unit of a is milliliter, the surface area of ​​the welding part (2) is b, the unit of b is square millimeter, the surface tension of the adhesive material is c, the unit of c is millinewtons per meter, the viscosity of the adhesive liquid of the adhesive material is d, the unit of d is millipascal seconds, and the value range of the correlation coefficient k is 15 to 20, wherein a=(b×k) / (c×d).

3. The method for preventing the tab (1) from tearing according to claim 2, characterized in that: The volume of the adhesive liquid of the adhesive material ranges from 0.05 ml to 0.3 ml, and / or the surface area of ​​the welding portion (2) ranges from 60 square millimeters to 96 square millimeters, and / or the surface tension of the adhesive material ranges from 30 millinewtons per meter to 40 millinewtons per meter, and / or the viscosity of the adhesive liquid of the adhesive material ranges from 200 milliPa·s to 500 milliPa·s.

4. The method for preventing the tab (1) from tearing according to claim 1, characterized in that: The adhesive material is any one of acrylic adhesive, modified epoxy acrylic structural adhesive, blue-red acrylic AB adhesive, and acrylate structural adhesive.

5. A tab (1), characterized in that: A welding portion (2) is formed on the pole lug (1), and the pole lug (1) is provided with a buffer member (3) which at least partially covers the welding portion (2).

6. The electrode tab (1) according to claim 5, characterized in that: The tensile shear strength of the buffer (3) ranges from 10 MPa to 30 MPa.

7. The electrode tab (1) according to claim 5, characterized in that: Along the thickness direction of the pole lug (1), the thickness of the buffer member (3) ranges from 0.5 mm to 3.5 mm.

8. The electrode tab (1) according to claim 5, characterized in that: The ratio of the contact area between the buffer component (3) and the welding portion (2) to the surface area of ​​the welding portion (2) is in the range of 0.8 to 1.

5.

9. The electrode tab (1) according to claim 5, characterized in that: The buffer (3) is a glue material, and the glue material is any one of acrylic glue, modified epoxy acrylic structural glue, blue-red acrylic AB glue, and acrylate structural glue.

10. An electrode assembly, characterized in that: It comprises the electrode lug (1) as claimed in any one of claims 5 to 9.

11. A battery, characterized in that: It comprises the electrode tab (1) as claimed in any one of claims 5 to 9, or the electrode assembly as claimed in claim 10.

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