Anti-tearing method for tab, and tab, electrode assembly and battery

Abstract

Provided in the present application are an anti-tearing method for a tab, and a tab, an electrode assembly and a battery. The anti-tearing method for a tab comprises: arranging an adhesive material on a welding portion of a tab, so as to form a buffering member that at least partially covers the tab. An adhesive material is arranged at a welding portion where a tab is prone to tearing, so as to form a buffering member, and the buffering member at least partially covers the welding portion, thereby preventing the tearing of the tab at the welding portion and reducing the defect rate caused by the tearing of the tab.

Description

Tear-resistant methods for electrodes, electrodes, electrode assemblies and batteries

[0001] This application claims priority to Chinese Patent Application No. 202510199722.2, filed on February 21, 2025, entitled “Tear-resistant method, tab, electrode assembly and battery”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of power battery technology, specifically to a method for preventing the tab from tearing, the tab, the electrode assembly, and the battery. Background Technology

[0003] In related technologies, tab tearing is a common phenomenon in battery production, mainly manifested as one to multiple layers of tearing near the tab. Tab tearing can affect the battery's electrical and safety performance. Invention Overview

[0004] In related technologies, the tabs are prone to tearing, which affects the battery's electrical and safety performance.

[0005] The embodiments of this application provide a method for preventing the tab from tearing, the tab, the electrode assembly, and the battery, which can improve the technical problem in the prior art where the tab is easily torn, affecting the electrical performance and safety performance of the battery.

[0006] In a first aspect, embodiments of this application provide a method for preventing the tab from tearing, comprising:

[0007] Adhesive material is applied to the welded portion of the electrode tab to form a buffer that at least partially covers the welded portion.

[0008] Secondly, embodiments of this application provide an electrode tab with a welded portion formed thereon, and the electrode tab is provided with a buffer member that at least partially covers the welded portion.

[0009] Thirdly, embodiments of this application provide an electrode assembly including the tab as described in any of the above embodiments.

[0010] Fourthly, embodiments of this application provide a battery including tabs as described in any of the above embodiments, or electrode assemblies as described in the above embodiments.

[0011] The beneficial effects of the embodiments of this application are as follows:

[0012] In the embodiments of this application, by providing adhesive material at the welded portion where the tab is prone to tearing, a buffer is formed to prevent the tab from tearing. The buffer at least partially covers the welded portion, thereby preventing the tab from tearing at the welded portion and reducing the defect rate of tab tearing. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 is a schematic diagram of the structure of the electrode sheet before the welding part is formed according to an embodiment of this application;

[0015] Figure 2 is a schematic diagram of the structure of the electrode sheet after the welding part is formed according to an embodiment of this application;

[0016] Figure 3 is a schematic diagram of the structure of the electrode provided in an embodiment of this application;

[0017] Figure 4 is a schematic diagram of the electrode structure provided in an embodiment of this application. Implementation methods of this application

[0018] Please refer to Figures 1 to 4. The anti-tear method for the electrode tab provided in the embodiments of this application includes: providing adhesive material on the welding part 2 of the electrode tab 1 to form a buffer 3 that at least partially covers the welding part 2.

[0019] In this embodiment, by providing adhesive material at the welded portion 2 where the tab 1 is prone to tearing, a buffer 3 is formed to prevent the tab 1 from tearing. The buffer 3 at least partially covers the welded portion 2, thereby preventing the tab 1 from tearing at the welded portion 2, reducing the defect rate of the tab 1 tearing, and alleviating the technical problem in the related art that the tab 1 is prone to tearing, which affects the electrical performance and safety performance of the battery.

[0020] The technical solution of this application will now be described in conjunction with specific embodiments.

[0021] It should be noted that the proximal end of tab 1 refers to the end of tab 1 that is close to the electrode 4 or the core package and is in direct contact with the ultrasonic welding head.

[0022] In one embodiment, referring to Figures 1 and 2, a welding portion 2 is formed on the tab 1, the welding portion 2 including multiple solder marks, and the welding portion 2 realizes the welding of the multi-layer tab 1 and the welding of the multi-layer tab 1 to the connecting piece.

[0023] It is understandable that the tab 1 in Figure 1 is not in contact with the ultrasonic welding head for welding. Figure 2 is a schematic diagram of the welding of the tab 1 by means of the ultrasonic welding head. When a welding part 2 is formed on the tab 1, the multi-layer tab 1 is welded and attached at the welding part 2 position, and a concave structure is formed.

[0024] The recessed structure refers to the circular pit within the dashed frame in Figure 2. This pit is a weld mark formed by the pressure of the ultrasonic welding head. It can be understood that using different numbers and shapes of welding heads will result in different numbers and shapes of pits. The pits are used to achieve the welding of the welding part 2 of the electrode 1 to the connecting piece.

[0025] In this process, the ultrasonic welding head presses down on the electrode tab to form a weld mark. At the weld mark, the electrode tab 1 is welded to the connecting piece on one side. After the welding is completed, a buffer 3 that at least partially covers the welded part 2 is formed on the other side of the electrode tab 1. This prevents the electrode tab 1 from tearing due to the high stress at the weld mark position during the movement of the electrode tab 1.

[0026] The welding part 2 is the area within the dashed box in Figure 2. Compared to other parts of the tab 1, the welding part 2 also has the aforementioned recessed structure, meaning that the surface of the welding part 2 is uneven.

[0027] It is understandable that, since the welded part 2 has multiple concave structures, while the ultrasonic welding head presses down to form concave structures, the welded part 2 can also be made to appear as a whole sunken.

[0028] It should be noted that large stresses are easily generated at the recessed structure, which can cause the weld 2 at that location to tear. Therefore, as shown in Figure 3, by forming a buffer 3 on the surface of the weld 2, the stress on the weld 2 at the recessed structure is reduced, thereby reducing the occurrence of tearing of the weld 2.

[0029] In one embodiment, the buffer 3 is formed on the welding part 2 using an adhesive coating process. The volume of the adhesive liquid is a, where a is milliliters; the surface area of ​​the welding part 2 is b, where b is square millimeters; the surface tension of the adhesive liquid is c, where c is millinewtons per meter; the viscosity of the adhesive liquid is d, where d is millipascals per second; and the correlation coefficient k ranges from 15 to 20, where a = (b × k) / (c × d).

[0030] The value of k can be, but is not limited to, 15, 17, 19, or 20.

[0031] Understandably, the units of k are used to balance the units on both sides of the equation so that the values ​​and units on both sides are the same.

[0032] It is understandable that by making the adhesive material satisfy a=(b×k) / (c×d), the tear defect rate of tab 1 can be further reduced.

[0033] In some embodiments, the buffer 3 may also be formed on the welded portion 2 by adhesive bonding.

[0034] In one embodiment, the volume of the adhesive liquid ranges from 0.05 ml to 0.3 ml, the surface area of ​​the welded part 2 ranges from 60 square millimeters to 96 square millimeters, the surface tension of the adhesive liquid ranges from 30 millinewtons to 40 millinewtons, and the viscosity of the adhesive liquid ranges from 200 millipascals to 500 millipascals.

[0035] The specific volume of the adhesive liquid can be, but is not limited to, 0.05, 0.13, 0.28, or 0.30.

[0036] The surface area of ​​the welded part 2 may be, but is not limited to, 60 square millimeters, 64 square millimeters, 80 square millimeters, or 96 square millimeters.

[0037] The surface tension of the adhesive material can be, but is not limited to, 30 millinewtons per meter, 33 millinewtons per meter, 36 millinewtons per meter, or 40 millinewtons per meter.

[0038] The viscosity of the adhesive solution can be, but is not limited to, 200 mPa·s, 300 mPa·s, 400 mPa·s, or 500 mPa·s.

[0039] This application provides three sets of embodiments and one set of comparative examples, as detailed in the table below:

[0040] Cell serial number, solder area (mm²), surface tension (mN / m), adhesive viscosity (mPa·s), adhesive volume (mL), tear defect rate (ppm): I 9630 2000 0.30 500 II 8033300 0.13 300 III 6040 5000 0.05 500 IV 6436 1000 0.28 1000

[0041] Among them, the cell serial numbers one, two, and three correspond to Examples one, two, and three and Comparative Example four, respectively. Examples one, two, and three all satisfy the range of the above-mentioned adhesive liquid volume, the surface area of ​​the welding part 2, the surface tension of the adhesive material, and the adhesive liquid viscosity of the adhesive material.

[0042] In some embodiments, the tensile shear strength of the buffer 3 ranges from 10 MPa to 30 MPa.

[0043] In some embodiments, the thickness of the buffer 3 ranges from 0.5 mm to 3.5 mm along the thickness direction of the tab 1.

[0044] In some embodiments, the ratio between the contact area of ​​the buffer 3 and the welded portion 2 and the surface area of ​​the welded portion 2 ranges from 0.8 to 1.5.

[0045] In some embodiments, the adhesive material is any one of acrylic adhesive, modified epoxy acrylic structural adhesive, cyan and red acrylic AB adhesive, and acrylate structural adhesive.

[0046] In Example 1, the volume a of the adhesive solution is 0.30 ml, the solder area b of the welding part 2 is 96 square millimeters, the surface tension c of the adhesive solution is 30 millinewtons per meter, and the viscosity d of the adhesive solution is 200 millipascals per second. At this time, a = (b × k) / (c × d) is satisfied, and the tear defect rate of the tab 1 of the adhesive solution in Example 1 is 500 ppm.

[0047] In Example 2, the volume a of the adhesive solution is 0.13 ml, the welding area b of the welding part 2 is 80 square millimeters, the surface tension c of the adhesive solution is 33 millinewtons per meter, and the viscosity d of the adhesive solution is 300 millipascals per second. At this time, a = (b × k) / (c × d) is satisfied, and the tear defect rate of the tab 1 of the adhesive solution in Example 2 is 300 ppm.

[0048] It is important to note that when the viscosity is less than 200 mPa·s, the adhesive is difficult to flow and position. After application, the adhesive tends to flow and is difficult to maintain at the bonding location, leading to uneven distribution and affecting the bonding effect. It is also difficult to accurately control the position of the adhesive, causing inconvenience to the operation. When the viscosity is greater than 500 mPa·s, the excessively high viscosity makes it difficult to apply the adhesive evenly. Greater pressure and force are required to spread the adhesive, which not only increases the difficulty of operation but may also lead to uneven coating thickness, affecting the overall bonding effect.

[0049] When the viscosity is less than 200 mPa·s, it will be impossible to form a glue layer with sufficient thickness and strength on the surface of the tab. The glue material cannot fully fill the pits on the surface of the tab. After curing, the effective contact area and intermolecular forces between the glue layer and the tab are small, which leads to a decrease in bonding strength and easy delamination.

[0050] In particular, when the viscosity is greater than 500 mPa·s, it will also lead to poor wettability. The adhesive material will not be able to fully wet the surface of the tab and will not be able to adhere well to the surface of the object to be bonded. This will form gaps or air bubbles 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 bond.

[0051] When the viscosity is greater than 500 mPa·s, the excessively high viscosity will hinder the chemical reaction inside the adhesive, slow down the curing process, prolong the overall curing time, and reduce production efficiency for large-scale production.

[0052] When the viscosity is greater than 500 mPa·s, the high viscosity adhesive may generate large internal stress during the curing process. When the internal stress exceeds a certain limit, it may cause the adhesive layer to crack or cause stress concentration at the interface between the tab and the adhesive layer, thereby reducing the bonding strength. In particular, for the bonding of the tab, this internal stress may damage the tab.

[0053] It should be noted that when the surface tension is greater than 40 millinewtons per meter, problems such as poor wetting, residual air bubbles, and edge shrinkage may occur, as detailed below:

[0054] Poor wetting: The adhesive material is difficult to spread on the surface of the electrode, and will form water droplets. It cannot fully cover and wet the surface of the electrode, resulting in a reduced contact area between the adhesive material and the electrode and a poorer bonding effect.

[0055] Residual air bubbles: During the adhesive coating process, due to the high surface tension, air bubbles are difficult to expel and tend to remain in the adhesive layer. These air bubbles will become weak points in the adhesive layer, reducing the strength and density of the adhesive layer and affecting the adhesive performance.

[0056] Edge shrinkage: During the curing process of the adhesive, the large surface tension will cause the adhesive to shrink towards the center, resulting in thinning of the adhesive layer at the edges or even missing adhesive, which will affect the integrity and reliability of the bond.

[0057] It is important to note that when the surface tension is less than 30 millinewtons per meter, it is difficult to form a stable adhesive layer due to the low surface tension. During the curing process, the adhesive cannot maintain its shape and position well due to the low surface tension, and it is prone to deformation and displacement, making it difficult to form a uniform and stable adhesive layer, thus affecting the bonding effect and the performance of the adhesive layer. Furthermore, the adsorption of dust and other impurities is enhanced: the surface energy of the adhesive with low surface tension is higher, making it easier to adsorb dust and impurities from the surrounding environment. These impurities mixed into the adhesive layer will reduce the purity and performance of the adhesive, affecting the bonding strength and durability.

[0058] For Example 3: the volume a of the adhesive is 0.05 ml, the solder area b of the welding part 2 is 60 square millimeters, the surface tension c of the adhesive is 40 millinewtons per meter, and the viscosity d of the adhesive is 500 millipascals per second; at this time, a = (b × k) / (c × d) is satisfied, and the tear defect rate of the tab 1 of the adhesive in Example 3 is 500 ppm.

[0059] For Comparative Example 4: the volume of the adhesive liquid a is 0.28 ml, the solder area b of the welded part 2 is 64 square millimeters, the surface tension c of the adhesive liquid is 36 millinewtons, and the viscosity d of the adhesive liquid is 100 millipascals per second; at this time, a = (b × k) / (c × d) is not satisfied, and the tear defect rate of the tab 1 of the adhesive liquid in Comparative Example 4 is 1000 ppm.

[0060] It is understandable that cell serial numbers one, two, and three are three sets of embodiments, and cell serial number four is a comparative example. Among them, embodiments one, two, and three satisfy the above formula a=(b×k) / (c×d), which can reduce the defect rate of tab 1 tearing to 500ppm. However, comparative example four does not satisfy the above formula a=(b×k) / (c×d). Compared with embodiments one, two, and three, its tab 1 tearing defect rate is 1000ppm, which is significantly higher than the tab 1 tearing defect rate of embodiments one, two, and three that satisfy the above formula a=(b×k) / (c×d).

[0061] In this embodiment, the volume of the adhesive liquid is in the range of 0.05 ml to 0.3 ml, the surface area of ​​the welded part 2 is in the range of 60 square millimeters to 96 square millimeters, the surface tension of the adhesive is in the range of 30 millinewtons to 40 millinewtons, and the viscosity of the adhesive liquid is in the range of 200 mPa·s to 500 mPa·s; and a = (b × k) / (c × d) is satisfied, thereby reducing the defect rate of tab 1 tearing to less than or equal to 500 ppm.

[0062] In one embodiment, the adhesive is any one of acrylic adhesive, modified epoxy acrylic structural adhesive, cyan and red acrylic AB adhesive, and acrylate structural adhesive.

[0063] The adhesive material includes monomer structure, crosslinking agent, initiator, plasticizer, and solvent.

[0064] The monomer structure includes at least one of acrylate monomers, methyl acrylate, ethyl acrylate, and butyl acrylate; the monomer structure is the main component of the adhesive material, accounting for 60% to 80% of the total mass of the adhesive material.

[0065] The crosslinking agent includes divinylbenzene or trimethylolpropane triacrylate. The crosslinking agent is used to form a three-dimensional network structure, enhance the cohesion and stability of the adhesive material, and accounts for 3% to 10% of the total mass of the adhesive material.

[0066] 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 adhesive material.

[0067] The plasticizer includes at least one of dibutyl phthalate or triphenyl phosphate, which can increase the flexibility of the adhesive and improve its handling performance. The plasticizer accounts for 5% to 15% of the total mass of the adhesive.

[0068] The solvent includes at least one of ethyl acetate, toluene, and acetone, used to adjust the viscosity of the adhesive, and the solvent accounts for 10% to 30% of the total mass of the adhesive.

[0069] It is understandable that choosing any one of the above adhesives, such as acrylic adhesive, modified epoxy acrylic structural adhesive, blue and red acrylic AB adhesive, or acrylic ester structural adhesive, can achieve good adhesion and polymerization performance.

[0070] This application also provides a method for preparing an adhesive material. Taking acrylic adhesive as an example, the steps are the same when the adhesive material is of other adhesive structures. The specific steps are as follows:

[0071] Step 1: Prepare the reaction vessel;

[0072] Specifically, a three-necked flask equipped with a stirrer, thermometer, and reflux condenser is selected as the reaction vessel. It should be noted that the reaction vessel should be cleaned and dried before use to ensure that it is clean and dry and that no impurities will affect the reaction.

[0073] Step 2: Conduct the polymerization reaction;

[0074] First, premix the ingredients. Accurately weigh the acrylate monomer, crosslinking agent, plasticizer, and initiator into a three-necked flask, turn on the stirrer, and stir at 200 rpm to 300 rpm for 15 to 30 minutes to ensure that the ingredients are fully mixed.

[0075] Next, heat polymerization is carried out; place the three-necked flask in a constant temperature water bath or oil bath, and slowly heat it 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 constant, and react for 3 to 6 hours, and observe the viscosity change of the reaction system.

[0076] Finally, viscosity adjustment is performed. After the reaction is complete, add an appropriate amount of solvent to adjust the viscosity based on the actual viscosity of the adhesive. If the viscosity is high, add the solvent slowly dropwise while continuously stirring until the viscosity reaches 200 to 500 mPa·s. It is important to note that during the solvent addition process, stirring should be done thoroughly to avoid excessive local viscosity differences.

[0077] Step 3: Post-processing;

[0078] First, degassing is performed. Since bubbles may be generated during the reaction, affecting the quality and performance of the adhesive, degassing is necessary. The reacted adhesive is placed in a vacuum environment for a period of time, for example, 30 to 60 minutes at a vacuum of 0.08 MPa to 0.1 MPa, to allow the bubbles to escape.

[0079] Secondly, filtration is performed; filter the adhesive material using a filter screen or filter cloth to remove any unreacted solid particles or impurities that may be present in the adhesive material, and obtain pure adhesive material.

[0080] Finally, package and store the adhesive. Pack the prepared adhesive into a well-sealed container and label the container with the name, ingredients, preparation date, and shelf life of the adhesive. Note that during storage, the container containing the adhesive should be placed in a cool, dry, and well-ventilated place, avoiding direct sunlight and high temperatures, which may cause the adhesive to fail.

[0081] Secondly, referring to Figures 1 to 3, embodiments of this application provide an electrode assembly, including an electrode sheet 4 and an electrode tab 1. The electrode tab 1 can be integrally extended from the electrode sheet 4, or it can be independently disposed from the electrode sheet 4 and formed by a connection method such as welding. A welding portion 2 is formed on the electrode tab 1, and a buffer member 3 is provided on the electrode tab 1 that at least partially covers the welding portion 2.

[0082] Among them, the welding part 2 of the electrode 1 is used to weld with the connecting piece, and the two ends of the connecting piece are respectively connected to the core package and the top cover assembly to form a current loop.

[0083] In this process, the welding part of the connecting piece and the tab 1 is first welded by a welding stamp. During the transportation of the tab 1 and the connecting piece, the tab 1 has a defect of high stress and easy tearing at the welding stamp position. Therefore, after the tab 1 and the connecting piece are welded, a buffer 3 is formed on the welding part 2. The buffer 3 plays the role of buffering the stress at the welding stamp position and preventing the welding part of the tab from tearing.

[0084] Among them, electrode 4 can be a positive electrode or a negative electrode.

[0085] The core package includes the aforementioned multiple electrode components, more specifically, a positive electrode, a negative electrode, and a separator located between the positive and negative electrodes.

[0086] The positive and negative electrodes are arranged at periodic intervals.

[0087] The top cover assembly is used to surround the core package together with the housing. The housing covers the sides and bottom of the core package, and the top cover assembly covers the top surface of the core package. The top cover assembly is connected to the connecting piece and is used to electrically connect the current of the core package to the external circuit through the top cover assembly.

[0088] It is understandable that the welding part 2 is the position where the electrode tab 1 contacts the ultrasonic welding head. Since the welding part 2 is prone to tearing, a buffer 3 is provided on the surface of the welding part 2 so that the buffer 3 at least partially covers the welding part 2, thereby preventing the electrode tab 1 from tearing and reducing the defect rate of the electrode tab 1 tearing.

[0089] In one embodiment, the tensile shear strength of the buffer 3 ranges from 10 MPa to 30 MPa.

[0090] The tensile shear strength of the buffer 3 can be any one of 10 MPa, 15 MPa, 20 MPa, 25 MPa, or 30 MPa.

[0091] Understandably, the tensile shear strength of the buffer 3 ranges from 10 MPa to 30 MPa, which allows the buffer 3 to better reduce the failure rate of the tab 1 tearing.

[0092] In one embodiment, the thickness of the buffer 3 ranges from 0.5 mm to 3.5 mm along the thickness direction of the electrode 4, that is, along the thickness direction of the tab 1.

[0093] The thickness of the buffer 3 can be any one of 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, or 3.5 mm.

[0094] Understandably, when the thickness of the buffer 3 is less than 0.5 mm, the buffer 3 provides poor anti-tear effect on the tab 1 in the electrode sheet 4; when the thickness of the buffer 3 is greater than 3.5 mm, the thickness of the buffer 3 will affect the adhesion of the insulating adhesive to the tab 1 in the subsequent process, and will also increase the probability of short circuit between the positive and negative electrodes of the battery.

[0095] In one embodiment, the ratio between the contact area of ​​the buffer 3 and the welded part 2 and the surface area of ​​the welded part 2 ranges from 0.8 to 1.5.

[0096] The ratio between the contact area of ​​the buffer 3 and the welded part 2 and the surface area of ​​the welded part 2 can be any one of 0.8, 1, 1.2, 1.3, or 1.5.

[0097] It is understandable that when the ratio between the contact area of ​​the buffer 3 and the welding part 2 and the surface area of ​​the welding part 2 is less than 0.8, the buffer 3 will have a poor anti-tear effect on the tab 1 in the electrode sheet 4. When the ratio between the contact area of ​​the buffer 3 and the welding part 2 and the surface area of ​​the welding part 2 is greater than 1.5, the bonding effect of the insulating adhesive on the buffer 3 will be affected when applying insulating adhesive to the tab 1 in the subsequent process. At the same time, it will also increase the probability of short circuit between the positive and negative electrodes of the battery.

[0098] In one embodiment, the surface area of ​​the welded portion 2 ranges from 30 square millimeters to 100 square millimeters.

[0099] The surface area of ​​the welded part 2 is the surface area of ​​the tab 1 within the dashed box in Figure 3.

[0100] The surface area of ​​the welded part 2 can be any one of 30 square millimeters, 50 square millimeters, 70 square millimeters, 90 square millimeters, or 100 square millimeters.

[0101] Understandably, 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 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 adhesive at the buffer 3 when applying insulating adhesive to the tab 1 in the subsequent process. At the same time, it will also increase the probability of short circuit between the positive and negative electrodes of the battery.

[0102] In one embodiment, the buffer 3 is arranged to overlap with the welded part 2 in the thickness direction of the tab 1.

[0103] It is understandable that by making the buffer 3 overlap with the welded part 2, the welded part 2 of the tab 1 can be better protected even when the volume and size of the buffer 3 are small, making the welded part 2 less likely to be torn and reducing the defect rate of the tab 1 being torn.

[0104] In one embodiment, the buffer 3 is an adhesive material, which is any one of acrylic adhesive, modified epoxy acrylic structural adhesive, cyan and red acrylic AB adhesive, and acrylate structural adhesive.

[0105] The adhesive material includes monomer structure, crosslinking agent, initiator, plasticizer, and solvent.

[0106] The monomer structure includes at least one of acrylate monomers, methyl acrylate, ethyl acrylate, and butyl acrylate; the monomer structure is the main component of the adhesive material, accounting for 60% to 80% of the total mass of the adhesive material.

[0107] The crosslinking agent includes divinylbenzene or trimethylolpropane triacrylate. The crosslinking agent is used to form a three-dimensional network structure, enhance the cohesion and stability of the adhesive material, and accounts for 3% to 10% of the total mass of the adhesive material.

[0108] 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 adhesive material.

[0109] The plasticizer includes at least one of dibutyl phthalate or triphenyl phosphate, which can increase the flexibility of the adhesive and improve its handling performance. The plasticizer accounts for 5% to 15% of the total mass of the adhesive.

[0110] The solvent includes at least one of ethyl acetate, toluene, and acetone, used to adjust the viscosity of the adhesive, and the solvent accounts for 10% to 30% of the total mass of the adhesive.

[0111] It is understandable that choosing any one of the above adhesives, such as acrylic adhesive, modified epoxy acrylic structural adhesive, blue and red acrylic AB adhesive, or acrylic ester structural adhesive, can achieve good adhesion and polymerization performance.

[0112] Thirdly, embodiments of this application provide an electrode assembly including an electrode 4 as described in any of the above embodiments.

[0113] Fourthly, embodiments of this application provide a battery including an electrode 4 as described in any of the above embodiments, or an electrode tab 1, or an electrode assembly as described in the above embodiments.

[0114] This application provides a method for preventing the tab 1 from tearing. By providing adhesive material at the welding part 2 of the tab 1 to form a buffer 3, the buffer 3 acts on the welding part 2 to prevent the welding part 2 from tearing and reduce the defect rate of the tab 1 tearing.

Claims

1. A method for preventing tearing of a tab (1), comprising: Adhesive material is provided on the welding part (2) of the tab (1) to form a buffer (3) that at least partially covers the welding part (2).

2. The method for preventing tearing of the tab (1) according to claim 1, wherein, The multilayer tabs (1) are welded and attached at the welding part (2) and have a recessed structure.

3. The method for preventing tearing of the tab (1) according to claim 1, wherein, The volume of the adhesive liquid is a, where a is milliliters; the surface area of ​​the welded part (2) is b, where b is square millimeters; the surface tension of the adhesive liquid is c, where c is millinewtons per meter; the viscosity of the adhesive liquid is d, where d is millipascals per second; and the correlation coefficient k ranges from 15 to 20, where a = (b × k) / (c × d).

4. The method for preventing tearing of the tab (1) according to claim 3, wherein, The volume of the adhesive liquid ranges from 0.05 ml to 0.3 ml.

5. The method for preventing tearing of the tab (1) according to claim 3, wherein, The surface area of ​​the welded part (2) ranges from 60 square millimeters to 96 square millimeters.

6. The method for preventing tearing of the tab (1) according to claim 3, wherein, The surface tension of the adhesive material ranges from 30 millinewtons per meter to 40 millinewtons per meter.

7. The method for preventing tearing of the tab (1) according to claim 3, wherein, The viscosity of the adhesive is in the range of 200 mPa·s to 500 mPa·s.

8. The method for preventing tearing of the tab (1) according to claim 1, wherein, The adhesive material is any one of acrylic adhesive, modified epoxy acrylic structural adhesive, blue and red acrylic AB adhesive, and acrylic ester structural adhesive.

9. The method for preventing tearing of the tab (1) according to claim 8, wherein, The adhesive material includes monomer structure, crosslinking agent, initiator, plasticizer, and solvent.

10. The method for preventing tearing of the tab (1) according to claim 9, wherein, The monomer structure includes at least one of acrylate monomers, methyl acrylate, ethyl acrylate, and butyl acrylate; the monomer structure is the main component of the adhesive material, accounting for 60% to 80% of the total mass of the adhesive material.

11. The method for preventing tearing of the tab (1) according to claim 9, wherein, 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 adhesive material. The crosslinking agent accounts for 3% to 10% of the total mass of the adhesive material.

12. The method for preventing tearing of the tab (1) according to claim 9, wherein, 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 adhesive material.

13. The method for preventing tearing of the tab (1) according to claim 9, wherein, The plasticizer includes at least one of dibutyl phthalate or triphenyl phosphate, which can increase the flexibility of the adhesive and improve its handling performance. The plasticizer accounts for 5% to 15% of the total mass of the adhesive.

14. The method for preventing tearing of the tab (1) according to claim 9, wherein, The solvent includes at least one of ethyl acetate, toluene, and acetone, and is used to adjust the viscosity of the adhesive material. The solvent accounts for 10% to 30% of the total mass of the adhesive material.

15. A type of electrode (1), wherein, A welding portion (2) is formed on the electrode tab (1), and a buffer (3) is provided on the electrode tab (1) to at least partially cover the welding portion (2).

16. The electrode tab (1) according to claim 5, wherein, The tensile shear strength of the buffer (3) ranges from 10 MPa to 30 MPa.

17. The electrode tab (1) according to claim 5, wherein, Along the thickness direction of the tab (1), the thickness of the buffer (3) ranges from 0.5 mm to 3.5 mm.

18. The electrode tab (1) according to claim 5, wherein, The ratio between the contact area of ​​the buffer (3) and the weld (2) and the surface area of ​​the weld (2) is in the range of 0.8 to 1.

5.

19. An electrode assembly comprising the tab (1) as described in any one of claims 5 to 9.

20. A battery comprising a tab (1) as described in any one of claims 15 to 19, or an electrode assembly as described in claim 19.

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