Battery

Abstract

The invention provides a battery which comprises a battery cell and an outer package, the battery cell and the outer package are connected through a battery protection double-sided tape, the battery protection double-sided tape comprises surface adhesive layers and a base material, the two sides of the base material are respectively compounded with one surface adhesive layer, and raw materials for preparing the surface adhesive layers comprise 50-95 parts of matrix resin, 1-50 parts of tackifying resin and 0-5 parts of a curing agent. The matrix resin comprises modified ethylene propylene diene monomer rubber grafted with a functional group, the functional group comprises carboxyl and / or hydroxyl, and the curing agent comprises at least one of amino resin, azopyridine and isocyanate. According to the battery, the battery cell and the outer package are well attached by utilizing the battery protection double-sided adhesive tape, so that the effect of fixing parts in the battery cell can be achieved, and the possibility of relative displacement of the battery cell and the outer package in the stages of battery liquid injection, formation and the like can be reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular, relates to a battery. Background Art

[0002] Adhesive tape products are widely used in various links of battery production. In existing battery products, adhesive tape products are usually used to achieve relative fixation between the battery pole group and the outer packaging material of the battery pole group. Therefore, on the one hand, it is beneficial to improve the formation uniformity and cell stability of the battery product during the formation process, and avoid displacement or deformation of the cell during the formation process. On the other hand, it is beneficial to improve the drop resistance of the battery product, and avoid the battery pole group from breaking or tearing due to the relative movement between the battery pole group and the outer packaging material of the battery pole group during the drop resistance test.

[0003] The battery product's battery pole group and the battery pole group outer packaging material are filled with electrolyte, so the tape products used as the battery pole group and the battery pole group outer packaging material should meet the requirements of electrolyte resistance. Otherwise, as the storage time and use time increase, the tape products will become ineffective and it will be difficult to effectively fix the battery pole group, thus reducing the stability and safety of the battery product.

[0004] With the development of science and technology, the requirements for battery products in various fields are getting higher and higher. The stability and safety of battery products are the performance indicators that the industry focuses on. How to further improve the stability and safety of battery products has great technical and economic value. Summary of the invention

[0005] In order to overcome the deficiencies and shortcomings of the prior art, an object of the present invention is to provide a battery having excellent structural stability and safety.

[0006] According to one aspect of the present invention, a battery is provided, comprising a battery cell and an outer package, wherein the battery cell and the outer package are connected by a battery protective double-sided tape, wherein the battery protective double-sided tape comprises a surface adhesive layer and a substrate, wherein both sides of the substrate are respectively compounded with a layer of the surface adhesive layer, and wherein, calculated by weight, the raw materials for preparing the surface adhesive layer comprise 50 to 95 parts of a main resin, 1 to 50 parts of a tackifying resin, and 0 to 5 parts of a curing agent, wherein the main resin comprises a modified ethylene propylene diene monomer rubber having a grafted functional group, wherein the functional group comprises a carboxyl group and / or a hydroxyl group, and the curing agent comprises at least one of an amino resin, a nitrogen pyridine, and an isocyanate.

[0007] The battery provided by this scheme uses a battery protection double-sided tape to well fit the battery cell and the outer packaging, which can not only fix the components in the battery cell, but also reduce the possibility of relative displacement between the battery cell and the outer packaging during the battery injection, formation and other stages. By optimizing the raw material composition ratio of the surface adhesive layer of the battery protection tape and using modified EPDM rubber grafted with carboxyl and / or hydroxyl groups, it can not only improve the peeling force of the surface adhesive layer on metal and substrate, but also improve the electrolyte resistance of the surface adhesive layer. Even if it is immersed in the electrolyte, it has good bonding performance, thereby improving the structural stability of the battery using the battery protection tape. It should be noted that EPDM (ethylene-propylene-diene monomer) is a copolymer of ethylene, propylene and a small amount of non-conjugated dienes, and is a type of EPDM. Because its main chain is composed of chemically stable saturated hydrocarbons and contains only unsaturated double bonds in the side chains, it has excellent aging resistance such as ozone resistance, heat resistance, and weather resistance, and has been widely used in the fields of automotive parts, waterproof materials for construction, wire and cable sheaths, heat-resistant hoses, tapes, automotive seals, etc. However, EPDM has a low surface energy, poor viscosity, and is easy to debond and lose adhesion, which limits the application of EPDM in the field of tapes.

[0008] On the one hand, by adopting modified EPDM rubber grafted with carboxyl and / or hydroxyl groups, and adjusting the ratio of the main resin and the tackifying resin in the surface adhesive layer, the bonding performance of the surface adhesive layer when immersed in the electrolyte can be improved, thereby reducing the probability of large displacement between the battery core and the outer packaging, preventing the battery core and the outer packaging from colliding and causing the battery structure to be destroyed, improving the stability of the electrode interface, and reducing the side reactions inside the battery. Specifically, the carboxyl and / or hydroxyl groups can affect the electronic distribution of the modified EPDM rubber, not only promoting the crosslinking degree of the surface adhesive layer formed by the main resin and the tackifying resin, but also the carboxyl and / or hydroxyl groups can increase the hydrogen bond content in the surface adhesive layer, thereby improving the compactness and permeation resistance of the surface adhesive layer, so that the surface adhesive layer that meets the above-mentioned formula requirements has good bonding performance after being immersed in the electrolyte, further improving the protection effect of the battery. On the other hand, the battery core is usually composed of a positive electrode, a separator, and a negative electrode, and the positive electrode current collector and / or the negative electrode current collector are generally exposed on the outermost side of the battery core. The battery using the double-sided battery protection tape has excellent structural tightness. The double-sided battery protection tape can fix the battery cell to prevent the components of the battery cell such as the positive electrode, diaphragm, and negative electrode from scattering, and improve the tightness between the components inside the battery cell. In addition, the battery using the double-sided battery protection tape has a tight fit between the battery cell and the outer packaging, which reduces the relative displacement between the battery cell and the outer packaging during the battery injection and formation stages, further improving the structural stability of the battery using the double-sided battery protection tape.

[0009] Preferably, in the surface adhesive layer, the grafting rate of the modified EPDM rubber in the main resin is 0.5-2%. By regulating the grafting rate of the modified EPDM rubber, the electrolyte resistance and bonding performance of the surface adhesive layer can be improved at the same time, so that the surface adhesive layer has good bonding performance before and after the electrolyte is soaked, thereby improving the structural stability of the battery in the stages of injection, formation, circulation, etc., thereby improving the electrochemical performance of the battery.

[0010] Preferably, the main resin also includes EPDM rubber. By using unmodified EPDM rubber and modified EPDM rubber grafted with carboxyl and / or hydroxyl groups as the main resin, the peeling force of the surface adhesive layer on the metal material can be further increased, that is, the bonding effect of the surface adhesive layer on the battery cell and / or outer packaging can be improved. Thus, the structural stability and cycle stability of the battery can be improved.

[0011] Preferably, the mass ratio of EPDM rubber to modified EPDM rubber is 60 to 90: 10 to 40. When the feeding amount of EPDM rubber and modified EPDM rubber in the main resin meets the above mass ratio range, the bonding performance of the surface adhesive layer to the battery cell, the outer packaging and the substrate is within an excellent range, so as to enhance the protective effect of the battery protective double-sided tape on the battery cell.

[0012] Preferably, in the surface adhesive layer, the tackifying resin includes a hydrogenated petroleum resin with a softening point of 100 to 150° C. By selecting a hydrogenated petroleum resin with a softening point of 100 to 150° C. as the tackifying resin, the surface adhesive layer formed by cross-linking the tackifying resin with the main resin has excellent electrolyte resistance and adhesion, and the battery exhibits excellent stability and structural density, preventing the loosening of the internal structure of the battery due to the loss of adhesion of the surface adhesive layer, thereby achieving the purpose of reducing burrs and leakage of the battery cell.

[0013] Preferably, the substrate includes a first base film, a second base film and a disbondable adhesive layer disposed between the first base film and the second base film. By providing a disbondable adhesive layer in the substrate, the anti-drop performance of the battery using the battery protection double-sided adhesive tape can be improved, wherein the disbondable adhesive layer has viscosity before being soaked in the electrolyte, and the viscosity of the disbondable adhesive layer to the first base film and the second base film will be significantly reduced under the immersion of the electrolyte. Generally speaking, the toughness and strength of the battery outer packaging material are significantly higher than the toughness and strength of the bonding surface of the battery cell surface. Therefore, during the drop of the battery product, the pulling force applied by the battery pole group outer packaging material to the conventional double-sided tape is greater than the pulling force applied by the battery pole group bonding surface to the double-sided tape. The difference in the above pulling force easily causes the double-sided tape to be attached to the side of the battery cell bonding surface to collapse and tear. In a more stringent drop test, there is even a phenomenon of aluminum foil tearing, which has an adverse effect on the anti-drop performance of the battery. By providing a debonding adhesive layer in the structure of the battery protection double-sided tape, the viscosity of the debonding adhesive layer decreases after the battery is formed, and a certain range of looseness occurs between the first base film and the second base film. In the process of the battery falling, it is not easy for the side of the battery protection double-sided tape adhered to the bonding surface of the battery cell to collapse or tear due to the difference in pulling force, thereby reducing the probability of burrs generated by the current collector at the bonding surface of the battery cell due to collapse and tearing, further improving the battery's anti-drop performance, and preventing the battery from leaking, short circuiting and other safety risks due to falling.

[0014] In the composition of the surface adhesive layer used in this solution, by adjusting the composition of the surface adhesive layer, industry insiders can flexibly make the surface adhesive layer reflect pressure sensitivity or heat sensitivity according to actual needs.

[0015] Preferably, in at least one surface adhesive layer, the mass ratio of the main resin to the tackifying resin is 50-70:20-50. The surface adhesive layer satisfying the above component composition exhibits pressure sensitivity, that is, the surface adhesive layer has excellent bonding properties both at room temperature and when immersed in electrolyte, and has strong bonding to metal materials and substrates.

[0016] When the surface adhesive layer is pressure-sensitive, preferably, the thickness of the surface adhesive layer is 2 to 4 μm.

[0017] Preferably, in at least one surface adhesive layer, the mass ratio of the main resin to the tackifying resin is 80 to 95: 1 to 10. The surface adhesive layer satisfying the above component composition exhibits heat sensitivity, that is, the surface adhesive layer has low viscosity at room temperature, but exhibits high peeling force in a high temperature environment.

[0018] When the surface adhesive layer is heat-sensitive, preferably, the thickness of the surface adhesive layer is 3 to 6 μm.

[0019] When the surface adhesive layer is heat-sensitive, preferably, calculated by weight, the raw materials used to prepare the surface adhesive layer include 80 to 95 parts of a main resin, 1 to 10 parts of a tackifying resin, and 0 to 2 parts of a curing agent.

[0020] Preferably, the surface adhesive layer further comprises a pigment, and the pigment comprises at least one of phthalocyanine blue, titanium dioxide, inorganic cobalt blue and inorganic cobalt green. By introducing the pigment into the raw material for preparing the surface adhesive layer, it is convenient for the adhesive machine or the staff to identify and locate the adhesive during the adhesive application process.

[0021] Preferably, the first base film includes at least one of polyethylene terephthalate (PET), polyimide (PI), and polypropylene (PP).

[0022] Preferably, the second base film includes at least one of polyethylene terephthalate (PET), polyimide (PI), and polypropylene (PP).

[0023] Preferably, the first base film has a thickness of 1 to 6 μm.

[0024] Preferably, the second base film has a thickness of 1 to 6 μm.

[0025] Preferably, the thickness of the debonding layer is 1 to 3 μm.

[0026] Preferably, the thickness of the battery protection double-sided tape is 8 to 25 μm.

[0027] Preferably, the battery protection double-sided adhesive tape further includes a release layer, and the release layer is composited with at least one surface adhesive layer.

[0028] Preferably, the outer packaging includes at least one of an aluminum-plastic film, an aluminum shell, and a steel shell.

[0029] Preferably, the battery includes at least one of a lithium-ion battery, a sodium-ion battery, and a lead-acid battery.

[0030] Preferably, the battery cell includes a first surface and a second surface arranged back to back, and the battery protective double-sided tape is attached to the edge of the battery cell, with any continuous layer of surface adhesive layer adhered to the first surface and the second surface of the battery cell, so that the battery protective double-sided tape is U-shaped and wraps around the edge of the battery cell.

[0031] Preferably, the surface adhesive layer disposed on one side of the substrate is a pressure-sensitive adhesive layer, and the surface adhesive layer disposed on the other layer of the substrate is a heat-sensitive adhesive layer. The battery protection double-sided adhesive tape is bonded to the battery cell with the pressure-sensitive adhesive layer; the battery protection double-sided adhesive tape is bonded to the outer packaging with the heat-sensitive adhesive layer. When the outer packaging is made of film materials such as aluminum-plastic film, a heat-sensitive adhesive layer is usually used for bonding to reduce wrinkles generated by the aluminum-plastic film during the bonding process.

[0032] Preferably, the battery protective double-sided tape is arranged on at least one set of opposite sides of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the interlayer structure of the battery protection double-sided tape used in the present invention;

[0034] Figure 2 A schematic diagram of the structure in which the battery protection double-sided tape is attached to the first surface of the battery;

[0035] Figure 3 A schematic diagram of the structure in which the battery protection double-sided tape is attached to the second surface of the battery;

[0036] Figure 4 Schematic diagram of the battery protection double-sided tape wrapped in a U shape around the edge of the battery cell.

[0037] The meanings of the reference numerals are as follows:

[0038] 1. battery cell; 11. first surface; 12. second surface;

[0039] 2. Battery protection double-sided tape; 21. First surface adhesive layer; 22. First base film; 23. Debondable adhesive layer; 24. Second base film; 25. Second surface adhesive layer. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the drawings in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0041] Example 1

[0042] This embodiment provides a battery protection double-sided adhesive tape and a battery.

[0043] (1) Battery protection double-sided tape

[0044] like Figure 1 As shown, the battery protection double-sided tape 2 includes a surface adhesive layer and a substrate, and the two sides of the substrate are respectively compounded with a layer of surface adhesive layer. The substrate includes a first base film 22, a second base film 24, and a debondable adhesive layer 23 disposed between the first base film 22 and the second base film 24, the surface adhesive layer disposed on one side of the substrate is the first surface adhesive layer 21, and the surface adhesive layer disposed on the other layer of the substrate is the second surface adhesive layer 25.

[0045] That is to say, the battery protection double-sided tape 2 includes a first surface adhesive layer 21, a first base film 22, a debonding adhesive layer 23, a second base film 24, and a second surface adhesive layer 25, which are arranged in sequence. Among them, the thickness of the first surface adhesive layer 21 is 3 μm, the thickness of the first base film 22 is 3 μm, the thickness of the debonding adhesive layer 23 is 2 μm, the thickness of the second base film 24 is 3 μm, and the thickness of the second surface adhesive layer 25 is 4 μm, so the thickness of the battery protection double-sided tape 2 is 15 μm.

[0046] Specifically, the first surface adhesive layer 21 is a pressure-sensitive adhesive layer, which is formed by curing glue A, wherein the glue A includes 60 parts of main resin, 35 parts of tackifying resin, 2 parts of curing agent and 10 parts of pigment. Among them, the main resin includes EPDM rubber and modified EPDM rubber in a mass ratio of 90:10, and the grafting rate of carboxyl groups in the modified EPDM rubber is 1%. The tackifying resin is a hydrogenated petroleum resin with a softening point of 125±5°C, the curing agent is an amino resin, and the pigment is phthalocyanine blue.

[0047] The second surface adhesive layer 25 is a heat-sensitive adhesive layer, which is formed by curing glue B, wherein the glue B includes 87 parts of main resin, 6 parts of tackifying resin and 1 part of curing agent. The main resin includes EPDM rubber and modified EPDM rubber in a mass ratio of 60:40, and the grafting rate of carboxyl groups in the modified EPDM rubber is 1%. The tackifying resin is a hydrogenated petroleum resin with a softening point of 105±5°C, and the curing agent is an amino resin.

[0048] The first base film 22 is made of polyethylene terephthalate (PET), and the second base film 24 is made of polyethylene terephthalate (PET).

[0049] The debondable adhesive layer 23 is formed by curing the glue C, which includes 80 parts of ethylene vinyl acetate and 20 parts of hydrogenated rosin resin.

[0050] The preparation method of the battery protection double-sided tape 2 includes the following operations:

[0051] Using a coating process, glue A is coated on the surface of the release film to form a first surface adhesive layer 21; then, the first base film is attached to the side of the first surface adhesive layer 21 away from the release film; glue C is coated on the surface of the first base film away from the first surface adhesive layer 21 to form a debonding adhesive layer 23 and then attached to the second base film 24; glue B is coated on the side of the second base film 24 away from the debonding adhesive layer 23 to form a second surface adhesive layer 25, thereby obtaining a battery protection double-sided tape 2.

[0052] The method for preparing carboxyl-modified EPDM rubber comprises the following steps:

[0053] Calculated by weight, 1.5-2.5 parts of carboxyl modified raw materials, 95-99 parts of ethylene propylene diene rubber, a catalyst and a solvent are mixed, and reacted at a reaction temperature of 80±5° C. in a nitrogen environment to prepare a carboxyl modified ternary rubber, wherein the grafting rate of the carboxyl group is 1%.

[0054] In other embodiments, the amount of main resin added, the type of tackifying resin, the softening point and the amount added, the mass ratio of EPDM rubber to modified EPDM rubber in glue A can be adjusted according to actual needs, and the addition of curing agent and / or pigment can be omitted; or the amount of main resin added, the type of tackifying resin, the softening point and the amount added, the mass ratio of EPDM rubber to modified EPDM rubber in glue B can be adjusted, and the addition of curing agent can be omitted; or the type and thickness of the first base film 22, the second base film 24, the debonding adhesive layer 23, the thickness of the first surface adhesive layer 21 and / or the second surface adhesive layer 25 can be adjusted independently; or the preparation method of the modified EPDM rubber can be adjusted. The premise is that it does not affect the normal use of the battery protection double-sided tape 2.

[0055] (2)Battery

[0056] The battery comprises a battery core 1 and an outer package, wherein the battery core 1 and the outer package are connected via a battery protection double-sided adhesive tape 2. The outer package is made of an aluminum-plastic film.

[0057] The method for preparing the battery includes the following operations:

[0058] The separator, the negative electrode sheet, the separator and the positive electrode sheet are stacked or wound into a battery cell 1, the battery cell 1 is fixed with the battery protection double-sided tape 2, and then packaged with an outer package, and a battery is formed through the steps of drying, injection, and formation. In addition, in the electrolyte used, the mass content of lithium salt (1 mol / L LiPF6) is 12.5%, and the mass content of organic solvent is 87.5%: calculated by mass ratio, ethylene carbonate: propylene carbonate: diethyl carbonate: ethyl propionate = 30:10:30:30 in the organic solvent.

[0059] Specifically, the specific bonding method of the battery protection double-sided tape 2 is as follows: Figure 2 and Figure 3 As shown, the battery protective double-sided tape 2 is attached to the four edge positions of the battery cell 1. The battery protective double-sided tape 2 is attached to the battery cell 1 with the first surface adhesive layer 21 (pressure-sensitive adhesive layer); the battery protective double-sided tape 2 is attached to the outer packaging with the second surface adhesive layer 25 (heat-sensitive adhesive layer). The battery cell 1 includes a first surface 11 and a second surface 12 that are arranged back to back. The continuous first surface adhesive layer 21 is attached to the first surface 11 and the second surface 12 of the battery cell 1, so that the battery protective double-sided tape 2 wraps around the edge of the battery cell 1 in a U shape, as shown in FIG. Figure 4 shown.

[0060] Example 2

[0061] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the first surface adhesive layer 21, the main resin in the glue A used to prepare the first surface adhesive layer 21 is adjusted, specifically, the modified EPDM rubber with the same mass and a hydroxyl grafting rate of 1% is used to replace the modified EPDM rubber in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with Example 1.

[0062] The preparation method of hydroxyl-modified EPDM rubber refers to the method provided in CN115386021A to prepare carboxyl-modified ternary rubber, and the grafting rate of carboxyl groups is 1%.

[0063] Example 3

[0064] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the first surface adhesive layer 21, the main resin in the glue A used to prepare the first surface adhesive layer 21 is adjusted, specifically, the modified EPDM rubber with the same mass and a carboxyl grafting rate of 0.3% is used to replace the modified EPDM rubber in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with Example 1.

[0065] Among them, the preparation method of carboxyl-modified EPDM rubber uses acrylic acid monomer as carboxyl-modified raw material to prepare carboxyl-modified ternary rubber, including the following operations:

[0066] Calculated by weight, 0.5 to 1 part of carboxyl modified raw material, 97 to 99 parts of ethylene propylene diene rubber, a catalyst and a solvent are mixed, and reacted at a reaction temperature of 80±5° C. in a nitrogen environment to prepare a carboxyl modified ternary rubber, wherein the grafting rate of the carboxyl group is 0.3%.

[0067] Example 4

[0068] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the first surface adhesive layer 21, the main resin in the glue A used to prepare the first surface adhesive layer 21 is adjusted, specifically, the modified EPDM rubber with the same mass and a carboxyl grafting rate of 0.5% is used to replace the modified EPDM rubber in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with Example 1.

[0069] Among them, the preparation method of carboxyl-modified EPDM rubber uses acrylic acid monomer as carboxyl-modified raw material to prepare carboxyl-modified ternary rubber, including the following operations:

[0070] Calculated by weight, 1 to 2 parts of carboxyl modified raw materials, 97 to 99 parts of ethylene propylene diene monomer rubber, a catalyst and a solvent are mixed, and reacted at a reaction temperature of 80±5° C. in a nitrogen environment to prepare a carboxyl modified ternary rubber, wherein the grafting rate of the carboxyl group is 0.5%.

[0071] Example 5

[0072] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the first surface adhesive layer 21, the main resin in the glue A used to prepare the first surface adhesive layer 21 is adjusted, specifically, the modified EPDM rubber with the same mass and a carboxyl grafting rate of 2% is used to replace the modified EPDM rubber in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with Example 1.

[0073] Among them, the preparation method of carboxyl-modified EPDM rubber uses acrylic acid monomer as carboxyl-modified raw material to prepare carboxyl-modified ternary rubber, including the following operations:

[0074] Calculated by weight, 2.5-4.5 parts of carboxyl modified raw materials, 95-99 parts of ethylene propylene diene rubber, a catalyst and a solvent are mixed, and reacted at a reaction temperature of 80±5° C. in a nitrogen environment to prepare a carboxyl modified ternary rubber, wherein the grafting rate of the carboxyl group is 2%.

[0075] Example 6

[0076] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the first surface adhesive layer 21, the main resin in the glue A used to prepare the first surface adhesive layer 21 is adjusted, specifically, the modified EPDM rubber with the same mass and a carboxyl grafting rate of 2.5% is used to replace the modified EPDM rubber in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with Example 1.

[0077] Among them, the preparation method of carboxyl-modified EPDM rubber uses acrylic acid monomer as carboxyl-modified raw material to prepare carboxyl-modified ternary rubber, including the following operations:

[0078] Calculated by weight, 3 to 5 parts of carboxyl modified raw materials, 95 to 99 parts of ethylene propylene diene rubber, a catalyst and a solvent are mixed, and reacted at a reaction temperature of 80±5° C. in a nitrogen environment to prepare a carboxyl modified ternary rubber, wherein the grafting rate of the carboxyl group is 2.5%.

[0079] Example 7

[0080] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the first surface adhesive layer 21, the tackifying resin in the glue A used to prepare the first surface adhesive layer 21 is adjusted, specifically, the tackifying resin in Example 1 is replaced by an equal mass of hydrogenated rosin resin with a softening point of 105±5°C. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0081] Example 8

[0082] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the first surface adhesive layer 21, the proportions of the main resin and the tackifying resin in the glue A used to prepare the first surface adhesive layer 21 are adjusted. Specifically, the main resin is 50 parts and the tackifying resin is 20 parts. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0083] Example 9

[0084] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the first surface adhesive layer 21, the proportions of the main resin and the tackifying resin in the glue A used to prepare the first surface adhesive layer 21 are adjusted. Specifically, the main resin is 70 parts and the tackifying resin is 50 parts. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0085] Comparative Example 1

[0086] This comparative example refers to the preparation method provided in Example 1 to prepare a double-sided tape and a battery. The difference between this comparative example and Example 1 is that in the process of preparing the first surface adhesive layer 21, the main resin in the glue A used to prepare the first surface adhesive layer 21 is adjusted, specifically, the unmodified EPDM rubber of the same mass is used to replace the modified EPDM rubber in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with Example 1.

[0087] Comparative Example 2

[0088] This comparative example refers to the preparation method provided in Example 1 to prepare a double-sided tape and a battery. The difference between this comparative example and Example 1 is that in the process of preparing the first surface adhesive layer 21, the main resin in the glue A used to prepare the first surface adhesive layer 21 is adjusted, specifically, the modified EPDM rubber in Example 1 is replaced by an equal mass of styrene-isoprene-styrene block copolymer (SIS). The grafting rate of the hydroxyl-modified styrene-isoprene-styrene block copolymer is 1%. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0089] Test Example 1

[0090] Test object: The glue A provided in Examples 1 to 9 and the glue A provided in Comparative Examples 1 to 2 are used to prepare single-sided tapes, respectively. Specifically, the single-sided tape comprises a first surface adhesive layer and a first base film which are compounded in sequence. The first surface adhesive layer is a pressure-sensitive adhesive layer, which is formed by the glue A provided in Examples 1 to 9 and the glue A provided in Comparative Examples 1 to 2, respectively. The above-mentioned single-sided adhesive layer is used as a test object.

[0091] Test items and test methods:

[0092] (1) Peel force test before immersion in electrolyte:

[0093] S1. In an environment of 23±2℃ and 50±5%RH, adhere copper foil to the pressure-sensitive adhesive surface of the test object.

[0094] S2. Then, 5000NS tape and steel plate are attached to the side of the copper foil facing away from the test object in sequence, and 5000NS tape is attached to the side of the test object facing away from the copper foil as a traction tape.

[0095] S3. Then use Kejian tensile gauge to clamp the steel plate and traction tape respectively for peeling force test. The peeling speed is 50mm / min and the peeling angle is 180°. Record the peeling force data and take the average value of a 60mm section after the reading stabilizes (if a severe jagged curve appears, take the average value of the maximum value of the curve every 10mm after stabilization). The judgment standard is the average of 5 parallel samples.

[0096] (2) Peel force test after immersion in electrolyte:

[0097] S1. In an environment of 23±2℃ and 50±5%RH, adhere copper foil to the pressure-sensitive adhesive surface of the test object.

[0098] S2. The composite structure formed by bonding the copper foil and the test object is then immersed in an electrolyte at a temperature of 85±1°C for 4 hours. The components of the electrolyte used are as follows: the mass content of lithium salt (1 mol / L LiPF6) is 12.5%, and the mass content of the organic solvent is 87.5%: calculated by mass ratio, in the organic solvent, ethylene carbonate: propylene carbonate: diethyl carbonate: ethyl propionate = 30:10:30:30.

[0099] S3. After the immersion is completed, the composite structure is taken out from the electrolyte.

[0100] S4. Restore the test environment to 23±2℃, 50±5%RH, and stick 5000NS tape and steel plate on the side of the copper foil facing away from the test object in sequence, and stick 5000NS tape on the side of the test object facing away from the copper foil as a traction tape.

[0101] S5. Then use Kejian tensile gauge to clamp the steel plate and traction tape respectively for peeling force test. The peeling speed is 50mm / min and the peeling angle is 180°. Record the peeling force data and take the average value of a 60mm section after the reading stabilizes (if a severe jagged curve appears, take the average value of the maximum value of the curve every 10mm after stabilization). The judgment standard is the average of 5 parallel samples.

[0102] Test results: as shown in Table 1.

[0103] Table 1. Peel force test results of pressure-sensitive adhesive layer

[0104]

[0105] Result analysis:

[0106] By comparing the peeling force test performance of Examples 1 to 9 with that of Comparative Examples 1 to 2 in Table 1, it can be found that the pressure-sensitive adhesive layer provided by Examples 1 to 9 has excellent bonding performance and electrolyte resistance compared with the pressure-sensitive adhesive layer provided by Comparative Examples 1 to 2, which is reflected in that the peeling force of the pressure-sensitive adhesive layer provided by Examples 1 to 9 after soaking in electrolyte is ≥ 0.05 N / mm. Among them, the pressure-sensitive adhesive layer of Comparative Example 1 uses unmodified EPDM rubber as the main resin, and the pressure-sensitive adhesive layer of Comparative Example 2 uses SIS and unmodified EPDM rubber as the main resin, but the pressure-sensitive adhesive layers of Comparative Examples 1 to 2 all show lower peeling force after soaking in electrolyte, which shows that when modified EPDM rubber with hydroxyl and / or carboxyl groups is introduced into the main resin, the obtained pressure-sensitive adhesive layer has both better bonding performance and electrolyte resistance.

[0107] Comparing the pressure-sensitive adhesive layers provided in Example 1 with those provided in Example 2, it can be found that the adhesive tape of Example 1 exhibits higher electrolyte resistance than the adhesive tape of Example 2, which is reflected in the excellent peeling force after being soaked in electrolyte. This shows that, compared with hydroxyl-modified EPDM rubber, the surface adhesive layer using carboxyl-modified EPDM rubber as the subject resin has better electrolyte resistance.

[0108] By comparing the adhesive tapes provided in Example 1 with those provided in Examples 3 to 6, it can be found that as the grafting rate of the modified EPDM rubber increases, the peeling force of the surface adhesive layer before being soaked in the electrolyte also increases, but the peeling force of the surface adhesive layer after being soaked in the electrolyte shows a trend of first increasing and then decreasing. Compared with the surface adhesive layers provided in Examples 3 and 6, the peeling force of the surface adhesive layers provided in Examples 1 and Examples 4 to 5 before and after being soaked in the electrolyte is greater than 0.08N / mm, which shows that when the grafting rate of the modified EPDM rubber is 0.5 to 2%, the surface adhesive layer has a relatively high peeling force before and after being soaked in the electrolyte, and in particular, the surface adhesive layer has excellent bonding performance after being soaked in the electrolyte.

[0109] By comparing the adhesive tapes provided in Example 1 with those provided in Example 7, it can be found that although the peeling forces of the surface adhesive layers provided in Example 1 and Example 7 before immersion in the electrolyte are similar, the peeling force of the surface adhesive layer provided in Example 1 after immersion in the electrolyte is higher, reflecting better electrolyte resistance. That is to say, when the softening point is 100-150°C, the use of hydrogenated petroleum resin as the tackifying resin can make the surface adhesive layer formed by cross-linking the tackifying resin and the main resin have excellent electrolyte resistance and bonding properties.

[0110] Example 10

[0111] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the second surface adhesive layer 25, the main resin in the glue B used to prepare the second surface adhesive layer 25 is adjusted, specifically, the modified EPDM rubber with the same mass and a carboxyl grafting rate of 0.5% is used to replace the modified EPDM rubber in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with Example 1.

[0112] Among them, the preparation method of carboxyl-modified EPDM rubber uses acrylic acid monomer as carboxyl-modified raw material to prepare carboxyl-modified ternary rubber, including the following operations:

[0113] Calculated by weight, 1 to 2 parts of carboxyl modified raw materials, 97 to 99 parts of ethylene propylene diene monomer rubber, a catalyst and a solvent are mixed, and reacted at a reaction temperature of 80±5° C. in a nitrogen environment to prepare a carboxyl modified ternary rubber, wherein the grafting rate of the carboxyl group is 0.5%.

[0114] Embodiment 11

[0115] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the second surface adhesive layer 25, the main resin in the glue B used to prepare the second surface adhesive layer 25 is adjusted, specifically, the modified EPDM rubber with the same mass and a carboxyl grafting rate of 2% is used to replace the modified EPDM rubber in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with Example 1.

[0116] Among them, the preparation method of carboxyl-modified EPDM rubber uses acrylic acid monomer as carboxyl-modified raw material to prepare carboxyl-modified ternary rubber, including the following operations:

[0117] Calculated by weight, 2.5-4.5 parts of carboxyl modified raw materials, 95-99 parts of ethylene propylene diene rubber, a catalyst and a solvent are mixed, and reacted at a reaction temperature of 80±5° C. in a nitrogen environment to prepare a carboxyl modified ternary rubber, wherein the grafting rate of the carboxyl group is 2%.

[0118] Example 12

[0119] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the second surface adhesive layer 25, the proportions of the main resin and the tackifying resin in the glue A used to prepare the second surface adhesive layer 25 are adjusted. Specifically, the main resin is 80 parts and the tackifying resin is 3 parts. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0120] Example 13

[0121] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the second surface adhesive layer 25, the proportions of the main resin and the tackifying resin in the glue A used to prepare the second surface adhesive layer 25 are adjusted. Specifically, the main resin is 95 parts and the tackifying resin is 10 parts. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0122] Comparative Example 3

[0123] This comparative example refers to the preparation method provided in Example 1 to prepare a double-sided tape and a battery. The difference between this comparative example and Example 1 is that in the process of preparing the second surface adhesive layer 25, the main resin in the glue A used to prepare the second surface adhesive layer 25 is adjusted, specifically, the unmodified EPDM rubber of the same mass is used to replace the modified EPDM rubber in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with Example 1.

[0124] Comparative Example 4

[0125] This comparative example refers to the preparation method provided in Example 1 to prepare a double-sided tape and a battery. The difference between this comparative example and Example 1 is that in the process of preparing the second surface adhesive layer 25, the main resin in the glue A used to prepare the second surface adhesive layer 25 is adjusted, specifically, the modified EPDM rubber in Example 1 is replaced by styrene-isoprene-styrene block copolymer (SIS) of equal mass. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0126] Test Example 2

[0127] Test object: The glue B provided in Example 1 and Examples 10 to 13 and the glue B provided in Comparative Examples 3 to 4 were used to prepare single-sided tapes, respectively. Specifically, the single-sided tapes included a second surface adhesive layer and a second base film which were compounded in sequence. The second surface adhesive layer was a heat-sensitive adhesive layer, which was formed by the glue B provided in Example 1 and Examples 10 to 13 and the glue B provided in Comparative Examples 3 to 4, respectively. The above-mentioned single-sided adhesive layers were used as test objects.

[0128] Test items and test methods:

[0129] (1) Peel force test before hot pressing:

[0130] S1. Under the environment of 23±2℃ and 50±5%RH, affix 5000NS tape as a traction tape on the side of the second basement membrane of the test object facing away from the heat-sensitive adhesive layer.

[0131] S2. Then, lay the test object with the traction tape on the steel plate with the thermal adhesive facing the steel plate, and use the Kejian tensile tester to clamp the steel plate and the traction tape for peeling force test. When the peeling force is ≤0.05N / mm, it is considered qualified.

[0132] (2) Peel force test after hot pressing and before immersion in electrolyte:

[0133] S1. In an environment of 23±2℃, 50±5%RH, lay the test object flat on a steel plate with the heat-sensitive adhesive surface facing the steel plate, stick copper foil on the pressure-sensitive adhesive surface of the test object, and then hot-press the composite structure composed of the copper foil, the test object and the steel plate. The hot-pressing temperature is 85℃, the hot-pressing pressure is 600kg, and the hot-pressing time is 30 minutes.

[0134] S2. The test environment was restored to 23±2°C and 50±5%RH, and then a 5000NS tape was attached to the side of the second base film of the test object facing away from the heat-sensitive adhesive layer as a traction tape.

[0135] S3. Then use Kejian tensile gauge to clamp the steel plate and traction tape respectively for peeling force test. The peeling speed is 50mm / min and the peeling angle is 180°. Record the peeling force data and take the average value of a 60mm section after the reading stabilizes (if a severe jagged curve appears, take the average value of the maximum value of the curve every 10mm after stabilization). The judgment standard is the average of 5 parallel samples.

[0136] (3) Peel force test after hot pressing and immersion in electrolyte:

[0137] S1. In an environment of 23±2℃, 50±5%RH, lay the test object flat on a steel plate with the heat-sensitive adhesive surface facing the steel plate, stick copper foil on the pressure-sensitive adhesive surface of the test object, and then hot-press the composite structure composed of the copper foil, the test object and the steel plate. The hot-pressing temperature is 85℃, the hot-pressing pressure is 600kg, and the hot-pressing time is 30 minutes.

[0138] S2. Then immerse the composite structure in an electrolyte at a temperature of 85±1°C for 4 hours. The components of the electrolyte used are as follows: the mass content of lithium salt (1 mol / L LiPF6) is 12.5%, and the mass content of the organic solvent is 87.5%: calculated by mass ratio, in the organic solvent, ethylene carbonate: propylene carbonate: diethyl carbonate: ethyl propionate = 30:10:30:30.

[0139] S3. After the immersion is completed, the composite structure is taken out from the electrolyte.

[0140] S4. Restore the test environment to 23±2°C and 50±5%RH, and then stick 5000NS tape as a traction tape on the side of the second base film of the test object facing away from the heat-sensitive adhesive layer.

[0141] S5. Then use Kejian tensile gauge to clamp the steel plate and traction tape respectively for peeling force test. The peeling speed is 50mm / min and the peeling angle is 180°. Record the peeling force data and take the average value of a 60mm section after the reading stabilizes (if a severe jagged curve appears, take the average value of the maximum value of the curve every 10mm after stabilization). The judgment standard is the average of 5 parallel samples.

[0142] Test results: as shown in Table 2.

[0143] Table 2. Peel force test results of thermal adhesive layer

[0144]

[0145]

[0146] Result analysis:

[0147] By comparing the peeling force test performance of Example 1, Examples 10 to 13 with Comparative Examples 3 to 4 in Table 1, it can be found that compared with the thermosensitive adhesive layer provided by Comparative Examples 3 to 4, the thermosensitive adhesive layer provided by Example 1 and Examples 10 to 13 has excellent adhesion performance and electrolyte resistance after hot pressing, which is reflected in that the peeling force of the thermosensitive adhesive layer provided by Example 1 and Examples 10 to 13 after hot pressing and before soaking in electrolyte is ≥0.15 N / mm, and the peeling force after hot pressing and soaking in electrolyte is ≥0.15 N / mm. Among them, the thermal adhesive layer of Comparative Example 1 uses unmodified EPDM rubber as the main resin, and the thermal adhesive layer of Comparative Example 2 uses styrene-isoprene-styrene block copolymer (SIS) and unmodified EPDM rubber as the main resin. However, the thermal adhesive layers of Comparative Examples 1 to 2 all show low peeling force after being immersed in electrolyte. This shows that when modified EPDM rubber with hydroxyl and / or carboxyl groups is introduced into the main resin, the obtained thermal adhesive layer has both better bonding performance and electrolyte resistance.

[0148] By comparing the adhesive tapes provided in Example 1 with those provided in Examples 10 to 11, it can be found that as the grafting rate of the modified EPDM rubber increases, the peeling force of the surface adhesive layer before being soaked in the electrolyte also increases, but the peeling force of the surface adhesive layer after being soaked in the electrolyte shows a trend of first increasing and then decreasing. The peeling forces of the surface adhesive layers provided in Examples 1 and Examples 10 to 11 before and after being soaked in the electrolyte are both within the excellent range, which indicates that when the grafting rate of the modified EPDM rubber is 0.5 to 2%, the peeling force of the surface adhesive layer before hot pressing is small, and it has good bonding properties after hot pressing, before being soaked in the electrolyte, and after hot pressing and then soaking in the electrolyte.

[0149] Furthermore, by comparing the peeling force test results of the pressure-sensitive adhesive layer shown in Table 1 with the peeling force test results of the heat-sensitive adhesive layer shown in Table 2, it can be found that when the mass ratio of the main resin to the tackifying resin in the surface adhesive layer is 50-70:20-50, the surface adhesive layer exhibits pressure sensitivity. When the mass ratio of the main resin to the tackifying resin in the surface adhesive layer is 80-95:1-10, the surface adhesive layer exhibits heat sensitivity.

[0150] Embodiment 15

[0151] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protection double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the battery protection double-sided tape, polyethylene terephthalate (PET) with a thickness of 4 μm is used as the substrate, replacing the substrate (first base film 22, debondable adhesive layer and second base film 24) in Example 1. Specifically, the battery protection double-sided tape includes a first surface adhesive layer 21, a substrate and a second surface adhesive layer 25 which are compounded in sequence. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0152] Test Example 3

[0153] Test objects: the batteries provided in Examples 1 to 15 and the batteries provided in Comparative Examples 1 to 4.

[0154] Test items and test methods:

[0155] (1) 1.8m vertical directional drop test: The six faces and four corners of the lithium battery are placed toward the ground, and then the lithium battery is dropped vertically from a height of 1.8m. After the drop test, the lithium battery voltage is tested. If the voltage change is less than 60mV, it is judged as passed, otherwise it is not passed; if the battery smokes and catches fire, it is judged as not passed.

[0156] The drop test pass rate is calculated according to formula (1).

[0157]

[0158] Test results: as shown in Table 3

[0159] Table 3. Battery drop test results

[0160]

[0161]

[0162] Result analysis:

[0163] It can be seen from the performance results of Examples 1 to 15 and Comparative Examples 1 to 4 that for the battery using the battery protective double-sided tape, the components in the battery cell are well fixed and the possibility of relative displacement between the battery cell and the outer packaging is reduced, which is reflected in that the battery passed the drop test.

[0164] Furthermore, by comparing the performance results of Example 1 with those of Example 15 in Table 3, it can be found that by providing a debonding adhesive layer in the substrate of the battery protection double-sided tape, the drop resistance of the battery to which the battery protection double-sided tape is applied can be improved.

[0165] Example 16

[0166] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protection double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the battery protection double-sided tape, glue B is used instead of glue A in Example 1, so that the first surface glue layer 21 is a heat-sensitive glue layer with a thickness of 3 μm. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0167] Embodiment 17

[0168] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protection double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that: in the process of preparing the battery protection double-sided tape, glue A is used instead of glue B in Example 1, so that the second surface adhesive layer 25 is a pressure-sensitive adhesive layer with a thickness of 4 μm. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0169] Embodiment 18

[0170] This embodiment refers to the preparation method provided in Example 1 to prepare a battery protective double-sided tape 2 and a battery. The difference between this embodiment and Example 1 is that during the preparation of the battery, a steel shell is used for the outer packaging. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0171] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A battery, characterized in that: It includes a battery cell and an outer package, wherein the battery cell and the outer package are connected by a battery protection double-sided tape, wherein the battery protection double-sided tape includes a surface adhesive layer and a substrate, and both sides of the substrate are respectively compounded with a layer of the surface adhesive layer. Calculated by weight, the raw materials used to prepare the surface adhesive layer include 50 to 95 parts of a main resin, 1 to 50 parts of a tackifying resin, and 0 to 5 parts of a curing agent. The main resin includes a modified EPDM rubber with a grafted functional group, the functional group includes a carboxyl group and / or a hydroxyl group, and the curing agent includes at least one of an amino resin, a nitrogen pyridine, and an isocyanate.

2. The battery according to claim 1, characterized in that: In the surface rubber layer, the grafting rate of the modified EPDM rubber in the main resin is 0.5-2%.

3. The battery according to claim 1, characterized in that: The main resin also includes EPDM rubber.

4. The battery according to claim 3, characterized in that: The mass ratio of the EPDM rubber to the modified EPDM rubber is 60-90:10-40.

5. The battery according to claim 1, characterized in that: In the surface adhesive layer, the tackifying resin includes a hydrogenated petroleum resin having a softening point of 100 to 150°C.

6. The battery according to claim 1, characterized in that: The substrate comprises a first base film, a second base film and a releasable adhesive layer disposed between the first base film and the second base film.

7. The battery according to claim 1, characterized in that: In at least one layer of the surface adhesive layer, the mass ratio of the main resin to the tackifying resin is 50-70:20-50.

8. The battery according to claim 1, characterized in that: In at least one layer of the surface adhesive layer, the mass ratio of the main resin to the tackifying resin is 80-95:1-10.

9. The battery according to claim 1, characterized in that: The battery protection double-sided adhesive tape has a thickness of 8 to 25 μm.

10. The battery according to any one of claims 1 to 9, characterized in that: The battery cell includes a first surface and a second surface arranged back to back, and the battery protective double-sided tape is attached to the edge of the battery cell. Any layer of the surface adhesive layer is simultaneously attached to the first surface and the second surface, so that the battery protective double-sided tape is U-shaped and wraps around the edge of the battery cell.

Images