Battery protection double-sided tape and battery using same

Abstract

The invention provides a battery protection double-sided tape and a battery using the same. The battery protection double-sided tape comprises a first adhesive layer, a protection function layer and a second adhesive layer which are sequentially stacked, the protection function layer comprises a first supporting layer and a second supporting layer; a connecting layer is further arranged between the first supporting layer and the second supporting layer, and the glass transition temperature Tg of the connecting layer is larger than or equal to-25 DEG C; the connecting layer comprises a reactive polymeric substance, and the mass content of the reactive polymeric substance in the connecting layer is not less than 60%; the reactive polymeric substance is selected from at least one of the following polymers A-D, the structural formula of the polymer A is # imgabs0, the structural formula of the polymer B is # imgabs1, and R is independently selected from at least one of H and CH3; r'is independently selected from at least one of H, CH3, CH2CH3 and CH2 (CH2) CH3, the structural formula of the polymer C is # imgabs2, and the polymer D is obtained by condensation polymerization of isocyanate with the functionality of at least 2 and polyol with the functionality of at least 2.

Description

Technical Field

[0001] The invention belongs to the field of batteries, and in particular relates to a battery protection double-sided adhesive tape and a battery using the same. Background Art

[0002] Secondary batteries have the characteristics of high operating voltage, high energy density, low self-discharge, multiple cycles, long service life, and high environmental protection. They are widely used in mobile phones, automobiles, notebooks and other fields. In existing secondary battery products, the battery pole group and the outer packaging film of the battery pole group are generally bonded by double-sided tape to achieve relative fixation. Generally speaking, the outer packaging film of the battery pole group mainly chooses aluminum-plastic film, and the bonding surface of the battery pole group is aluminum foil or polyethylene diaphragm. The toughness and strength of the aluminum-plastic film are significantly higher than the toughness and strength of the bonding surface of the battery pole group. Therefore, during the falling process of the secondary battery product, the pulling force applied by the aluminum-plastic film to the double-sided tape is greater than the pulling force applied by the bonding surface of the battery pole group to the double-sided tape. The difference in the above pulling force can easily cause the double-sided tape to collapse and tear on the side of the battery pole group. In more stringent drop tests, there is even a phenomenon of aluminum foil tearing, which has an adverse effect on the drop resistance of the secondary battery.

[0003] With the development of science and technology, various fields have higher and higher requirements for secondary batteries. For example, higher energy density, more stable performance and greater safety are required for secondary batteries. Therefore, based on the development of higher energy density of secondary batteries, the current collector of secondary batteries is getting thinner and thinner, from the previous thickness of 6-10μm aluminum foil to 4-6μm. This makes it easier for the current collector of the battery cell to burr and tear during the falling process of the secondary battery, thus affecting the stability and safety of the secondary battery. In this context, it is of great significance to further optimize the stability and safety of secondary batteries. Summary of the invention

[0004] In order to improve the anti-drop performance of a battery, the present invention provides a battery protection double-sided adhesive tape and a battery using the same.

[0005] According to one aspect of the present invention, a battery protection double-sided tape is provided, which comprises a first adhesive layer, a protective functional layer, and a second adhesive layer which are sequentially stacked; the protective functional layer comprises a first supporting layer and a second supporting layer; and a connecting layer is further provided between the first supporting layer and the second supporting layer, and the glass transition temperature Tg of the connecting layer is ≥-25°C; the connecting layer comprises a reactive polymer substance, and the mass content of the reactive polymer substance in the connecting layer is not less than 60%; the reactive polymer substance is selected from at least one polymer of the following A to D, and the structural formula of polymer A is The structural formula of polymer B is R is independently selected from at least one of H and CH3; R' is independently selected from at least one of H, CH3, CH2CH3, and CH2(CH2)CH3; the structural formula of polymer C is The polymer D is obtained by polycondensation of an isocyanate having a functionality of at least 2 and a polyol having a functionality of at least 2.

[0006] The present invention can make the battery protection double-sided adhesive have a responsive viscosity change by selecting at least one of polymers A to D. Specifically, when the battery protection double-sided adhesive provided by the present invention is immersed in an organic acid ester solution at 85°C for 4 hours, the peeling force retention rate between the connecting layer and the first supporting layer and the second supporting layer does not exceed 80%. Furthermore, the present invention can improve the penetration of the electrolyte into the connecting layer and accelerate the decrease of the peeling force of the connecting layer by controlling the glass transition temperature of the connecting layer to meet a specific range, thereby improving the battery's anti-drop ability and adapting to the industry development of secondary batteries. Among them, the glass transition temperature (Glass Transition Temperatur

[0007] Preferably, the glass transition temperature T of the connecting layer is g =-25℃~0℃.

[0008] Preferably, the area of ​​the connecting layer independently satisfies a or b; a. The area of ​​the connecting layer is 20-70% of the first supporting layer; b. The area of ​​the connecting layer is 20-70% of the second supporting layer. Further, the area of ​​the connecting layer will affect the peeling force retention rate between the first supporting layer and the second supporting layer, respectively. Specifically, when the area of ​​the connecting layer is too high, it will affect the penetration of the electrolyte; when the area of ​​the connecting layer is too low, it will affect the bonding effect of the connecting layer with the first supporting layer and the second supporting layer, respectively.

[0009] Preferably, the connection layer includes adhesive areas; in the connection layer, the number of adhesive areas is not less than 1; and the maximum diameter of the adhesive areas is 0.1 to 1 mm; and the concentricity between the adhesive areas is 0.2 to 2 mm.

[0010] Preferably, a blank portion is provided between the first supporting layer and the second supporting layer; the blank portion and the connecting layer are in the same plane, and the blank portion and the connecting layer are parallel to the first supporting layer and the second supporting layer; wherein the connecting layer is composed of a number greater than or equal to 1 rectangular adhesive area with a width of 1 to 5 mm, and the blank portion is composed of a number greater than or equal to 1 rectangular adhesive-free area with a width of 1 to 5 mm; and the rectangular adhesive-free area and the rectangular adhesive area are spaced apart.

[0011] Preferably, the connecting layer further comprises a viscous substance having a mass content of no more than 50%, and the viscous substance comprises at least one of rosin resin, terpene phenol resin, and petroleum resin. In the present invention, the glass transition temperature of the polymer A used is 60 to 70°C, the glass transition temperature of the polymer B is -30 to -45°C, the glass transition temperature of the polymer C is -10 to 15°C, and the glass transition temperature of the polymer D is 45 to 60°C. In the present invention, the sensitivity of the responsive viscosity change of the battery protection double-sided tape is improved by introducing a viscous substance.

[0012] Preferably, the mass content of the adhesive substance in the connecting layer is 20-50%.

[0013] Preferably, the connection layer further includes a curing agent with a mass content of no more than 3%, and the curing agent includes at least one of amino resin and nitrogen pyridine. Further, by introducing the curing agent, on the one hand, the polymer B can be promoted to form a firm three-dimensional network to prevent the formed connection layer from dissolving in the electrolyte and affecting its electrochemical performance; on the other hand, the peeling force of the connection layer can be further accelerated to reduce, thereby improving the drop resistance of the battery.

[0014] Preferably, the first adhesive layer comprises 40-80% functional polymer A and 18-50% hydrogenated petroleum resin in terms of mass percentage; wherein the functional polymer A comprises at least one of styrene-isoprene-styrene block copolymer (SIS), polystyrene-polybutadiene-styrene block copolymer (SBS), styrene-butadiene rubber (SBR), hydrogenated styrene-polybutadiene-styrene block copolymer (SEBS), amorphous α-olefin copolymer (APAO), polyolefin elastomer (POE), polypropylene (PP), and polyisobutylene (PIB). The first adhesive layer provided by the present invention is pressure-sensitive, has a high peeling force after contacting the surface of the battery cell, and has good electrolyte resistance.

[0015] Preferably, the softening point of the hydrogenated petroleum resin is between 100 and 150°C.

[0016] Preferably, the first adhesive layer further comprises a pigment, and the mass content of the pigment is not higher than 20%.

[0017] Preferably, the pigment includes at least one of phthalocyanine blue, titanium dioxide, inorganic cobalt blue and inorganic cobalt green.

[0018] Preferably, the second adhesive layer comprises 80-95% functional polymer B and 5-20% hydrogenated petroleum resin by weight percentage; wherein the functional polymer B comprises at least one of styrene-isoprene-styrene block copolymer (SIS), polystyrene-polybutadiene-styrene block copolymer (SBS), styrene-butadiene rubber (SBR), hydrogenated styrene-polybutadiene-styrene block copolymer (SEBS), amorphous α-olefin copolymer (APAO), polyolefin elastomer (POE), polypropylene (PP), and polyisobutylene (PIB). The second adhesive layer provided by the present invention is heat-sensitive, has a high peeling force after contacting the protective layer of the battery, and has good electrolyte resistance.

[0019] Preferably, the softening point of the hydrogenated petroleum resin is between 100 and 150°C.

[0020] Preferably, the thickness of the connecting layer is 1 to 3 μm; and / or the thickness of the first adhesive layer is 2 to 4 μm; and / or the thickness of the second adhesive layer is 3 to 6 μm.

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

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

[0023] A second aspect of the present invention provides a battery, comprising a battery cell, a protective layer and the battery protective double-sided tape as described above; wherein a first adhesive layer is attached to the surface of the battery cell, and an inner surface of the protective layer is attached to a second adhesive layer.

[0024] Preferably, the protective layer includes at least one of an aluminum-plastic film, a steel shell, an aluminum shell, and a plastic shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A cross-sectional view of the battery protection double-sided tape provided in Example 1 of the present invention;

[0026] Figure 2 A schematic diagram of the structure of a battery provided in Example 1 of the present invention;

[0027] Figure 3 Another schematic diagram of the structure of the battery provided in Example 1 of the present invention;

[0028] Figure 4 This is a schematic diagram of a battery protective double-sided adhesive tape in a battery provided in Example 1 of the present invention being wrapped around the edge of a battery cell in a U shape;

[0029] Figure 5A schematic diagram of the adhesive area of ​​the connecting layer of the battery protection double-sided tape provided in Example 11 of the present invention;

[0030] Figure 6 A schematic diagram of a connecting layer and a blank portion in a battery protection double-sided tape provided in Example 12 of the present invention;

[0031] The above-mentioned reference numerals have the following meanings:

[0032] 1. battery cell; 11. first surface; 12. second surface;

[0033] 2. Battery protection double-sided tape; 21. First adhesive layer; 22. First support layer; 23. Connecting layer; 231. Adhesive area; 232. Adhesive-free area; 24. Second support layer; 25. Second adhesive layer; DETAILED DESCRIPTION

[0034] 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.

[0035] Example 1

[0036] 1. Preparation of battery protection double-sided tape

[0037] The raw materials required for preparing the battery protection double-sided adhesive tape 2 in this embodiment are shown in Table 1.

[0038] Specifically, the battery protection double-sided tape 2 is prepared in this embodiment as follows: a coating process is adopted to coat the adhesive of the first adhesive layer 21 on the surface of the release film to form the first adhesive layer 21; then the first support layer 22 is attached to the side of the first adhesive layer 21 away from the release film; the adhesive of the connecting layer 23 is coated on the surface of the first support layer 22 away from the first adhesive layer 21 to form the connecting layer 23, and then the second support layer 24 is attached; the adhesive of the second adhesive layer 25 is coated on the side of the second support layer 24 away from the connecting layer 23 to form the second adhesive layer 25, and the battery protection double-sided tape 2 is obtained. Figure 1 shown.

[0039] Table 1. Raw materials required for this example

[0040]

[0041] 2. Preparation of Cells

[0042] The separator, negative electrode sheet, separator and positive electrode sheet are stacked or wound together to form a battery cell. The outside of the battery cell 1 is fixed with the above-mentioned battery protection double-sided tape 2, and then hot-pressed with aluminum-plastic film. After drying, liquid injection, formation and other steps, a battery is formed.

[0043] In the battery, the packaging film wraps the battery cell 1, see Figure 2 and Figure 3 As shown, the battery cell 1 includes a first surface 11 and a second surface 12 which are arranged back to back, and the battery protective double-sided tape 2 is attached to the four edge positions of the battery cell 1. The first adhesive layer 21 is attached to the first surface 11 and the second surface 12 at the same time, so that the battery protective double-sided tape 2 is U-shaped and wraps around the four edges of the battery cell 1, so that one side of the first adhesive layer 21 in the battery protective double-sided tape 2 is attached to the surface of the battery cell 1, and one side of the second adhesive layer 25 is attached to the surface of the aluminum-plastic film, as shown in FIG. Figure 4 shown.

[0044] The thickness of the aluminum foil in the battery cell is 4 μm, and the area of ​​the connecting layer 23 is completely consistent with that of the first supporting layer 22 and the second supporting layer 24. In addition, in the electrolyte used, 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, ethylene carbonate: propylene carbonate: diethyl carbonate: ethyl propionate = 30:10:30:30 in the organic solvent.

[0045] Example 2

[0046] This embodiment prepares a battery protective double-sided tape and a battery using the same with reference to the formula and method provided in Example 1. The difference from Example 1 is that when preparing the battery protective double-sided tape, this embodiment replaces polymer A with polymer C in an equal mass fraction. Except for the above difference, the operating steps for preparing the battery protective double-sided tape and a battery using the same in this embodiment are strictly consistent with those in Example 1.

[0047] Example 3

[0048] This embodiment prepares a battery protective double-sided tape and a battery using the same with reference to the formula and method provided in Example 1. The difference from Example 1 is that when preparing the battery protective double-sided tape, this embodiment replaces polymer A with polymer D in equal mass fraction. Except for the above difference, the operating steps for preparing the battery protective double-sided tape and a battery using the same in this embodiment are strictly consistent with those in Example 1.

[0049] Example 4

[0050] This embodiment prepares a battery protection double-sided tape and a battery using the same with reference to the formula and method provided in Example 1. The difference from Example 1 is that when preparing the battery protection double-sided tape in this embodiment, the formula for preparing the connecting layer 23 is 98% polymer B and 2% nitrogen pyridine, calculated by mass percentage. Except for the above differences, the operating steps for preparing the battery protection double-sided tape and a battery using the same in this embodiment are strictly consistent with those in Example 1.

[0051] Example 5

[0052] This embodiment refers to the formula and method provided in Example 4 to prepare a battery protection double-sided tape and a battery using the same. The difference from Example 4 is that when preparing the battery protection double-sided tape in this embodiment, the T of the connection layer 23 prepared is g =10°C. Except for the above differences, the steps for preparing the battery protective double-sided tape and the battery using the same in this embodiment are strictly consistent with those in Example 4. Specifically, in this embodiment, the formula of the connecting layer 23 is: 77.5% polymer B, 2.5% amino resin, 22% petroleum resin, so as to make the T of the connecting layer 23 g The value is adjusted from -23℃ to 10℃.

[0053] Example 6

[0054] This embodiment refers to the formula and method provided in Example 4 to prepare a battery protection double-sided tape and a battery using the same. The difference from Example 4 is that when preparing the battery protection double-sided tape in this embodiment, the Tg of the prepared connection layer 23 is 0°C. In addition to the above differences, the operation steps of preparing the battery protection double-sided tape and the battery using the same in this embodiment are strictly consistent with those in Example 4. Specifically, in this embodiment, the formula of the connection layer 23 is: 98.6% polymer B, 1.3% amino resin, 0.1% terpene phenol resin, so as to increase the Tg of the connection layer 23. g The value is adjusted from -23℃ to 0℃.

[0055] Example 7

[0056] This embodiment refers to the formula and method provided in Example 4 to prepare a battery protection double-sided tape and a battery using the same. The difference from Example 4 is that when preparing the battery protection double-sided tape in this embodiment, the Tg of the prepared connection layer 23 is -25°C. In addition to the above differences, the operation steps of preparing the battery protection double-sided tape and the battery using the same in this embodiment are strictly consistent with those in Example 4. Specifically, in this embodiment, the formula of the connection layer 23 is: 99.6% polymer B, 0.3% nitrogen pyridine, and 0.1% rosin resin, so as to increase the Tg of the connection layer 23. g The value was adjusted from -23℃ to -25℃.

[0057] Example 8

[0058] This embodiment prepares a battery protection double-sided tape and a battery using the same with reference to the formula and method provided in Embodiment 4. The difference from Embodiment 4 is that when preparing the battery protection double-sided tape, this embodiment uses an amino resin of equal mass fraction to replace nitrogen pyridine. Except for the above difference, the operating steps for preparing the battery protection double-sided tape and a battery using the same in this embodiment are strictly consistent with those in Embodiment 4.

[0059] Example 9

[0060] This embodiment prepares a battery protection double-sided tape and a battery using the same with reference to the formula and method provided in Embodiment 1. The difference from Embodiment 1 is that when preparing the battery protection double-sided tape, this embodiment uses terpene phenol resin in an equal mass fraction to replace rosin resin. Except for the above difference, the operating steps for preparing the battery protection double-sided tape and a battery using the same in this embodiment are strictly consistent with those in Embodiment 1.

[0061] Example 10

[0062] This embodiment prepares a battery protection double-sided tape and a battery using the same with reference to the formula and method provided in Embodiment 1. The difference from Embodiment 1 is that when preparing the battery protection double-sided tape, this embodiment uses an equal mass fraction of petroleum resin instead of rosin resin. Except for the above difference, the operating steps for preparing the battery protection double-sided tape and a battery using the same in this embodiment are strictly consistent with those in Embodiment 1.

[0063] Embodiment 11

[0064] This embodiment refers to the formula and method provided in Example 4 to prepare the battery protection double-sided tape and the battery using it. The difference from Example 4 is that when preparing the battery protection double-sided tape in this embodiment, the area of ​​the connection layer 23 prepared is 60% of the first support layer 22. In addition to the above differences, the operation steps of preparing the battery protection double-sided tape and the battery using it in this embodiment are strictly consistent with those in Example 1. Specifically, in this embodiment, the connection layer 23 includes glue areas 231, the number of glue areas 231 is not less than 1, and the maximum diameter of the glue areas is 0.5mm; the concentricity between the glue areas is 1mm, and the structural schematic diagram of the connection layer 23 is as shown in FIG. Figure 5 shown.

[0065] Example 12

[0066] This embodiment refers to the formula and method provided in Example 4 to prepare a battery protection double-sided tape and a battery using the same. The difference from Example 4 is that when preparing the battery protection double-sided tape in this embodiment, the area of ​​the prepared connecting layer 23 is 60% of the first support layer 22. In addition to the above differences, the operating steps of preparing the battery protection double-sided tape and the battery using the same in this embodiment are strictly consistent with those in Example 1. Specifically, in this embodiment, a blank portion is also provided between the first support layer 22 and the second support layer 24; the blank portion and the connecting layer 23 are in the same plane, and the blank portion and the connecting layer 23 are parallel to the first support layer 22 and the second support layer 24; wherein the connecting layer 23 is composed of a number of 2mm wide rectangular adhesive areas 231 greater than or equal to 1, and the blank portion is composed of a number of 2mm wide rectangular non-adhesive areas 232 greater than or equal to 1; the rectangular non-adhesive areas 231 and the rectangular adhesive areas 232 are arranged at intervals, and the structural schematic diagram of the connecting layer 23 is shown in FIG. Figure 6 shown.

[0067] Comparative Example 1

[0068] This comparative example refers to the formula and method provided in Example 1 to prepare the battery protection double-sided tape and the battery using the same. The difference from Example 1 is that the battery protection double-sided tape used in this comparative example refers to the formula and ratio of the third pressure-sensitive adhesive layer provided in Example 3 of CN114958230B to prepare the connecting layer 23 (thickness of 6 μm), and the thickness of the aluminum foil in the battery is 10 μm. In addition to the above differences, the operation steps of preparing the battery protection double-sided tape and using the same battery in this comparative example are strictly consistent with Example 1. Specifically, in this comparative example, the formula of the connecting layer 23 is: 80% ethylene vinyl acetate, 20% hydrogenated rosin resin.

[0069] Comparative Example 2

[0070] This comparative example refers to the formula and method provided in Example 1 to prepare the battery protection double-sided tape and the battery using the same. The difference from Example 1 is that the battery protection double-sided tape used in this comparative example refers to the formula and ratio of the third pressure-sensitive adhesive layer provided in Example 3 of CN114958230B to prepare the connecting layer 23 (thickness of 6 μm), and the thickness of the aluminum foil in the battery is 4 μm. In addition to the above differences, the operation steps of preparing the battery protection double-sided tape and using the same battery in this comparative example are strictly consistent with Example 1. Specifically, in this comparative example, the formula of the connecting layer 23 is: 80% ethylene vinyl acetate, 20% hydrogenated rosin resin.

[0071] Comparative Example 3

[0072] This comparative example refers to the formula and method provided in Example 4 to prepare a battery protective double-sided tape and a battery using the same. The difference from Example 4 is that when preparing the battery protective double-sided tape in this comparative example, the T of the obtained connecting layer 23 isg =-45°C. Except for the above differences, the operation steps of preparing the battery protective double-sided adhesive tape and the battery using the same in this comparative example are strictly consistent with those in Example 4. Specifically, in this comparative example, the formula of the connecting layer 23 is 99.8% polymer B, 0.1% nitrogen pyridine, and 0.1% rosin resin, so as to make the T of the connecting layer 23 g The value is adjusted from -23℃ to -45℃.

[0073] Test Case

[0074] 1. Test subjects

[0075] The battery protection double-sided adhesive tapes and batteries prepared in Examples 1 to 12 and Comparative Examples 1 to 3.

[0076] 2. Test Method

[0077] (1) Drop test:

[0078] ①1.8m vertical directional drop test: Make the six faces and four corners of the lithium battery face the ground, and then drop the lithium battery vertically from a height of 1.8m. After the drop test, test the lithium battery voltage. 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.

[0079] ②2m vertical directional drop test: Make the 6 faces and 4 corners of the lithium battery face the ground, and then drop the lithium battery vertically from a height of 2m. After the drop test, test the lithium battery voltage. 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.

[0080] The drop test pass rate is calculated according to formula (1).

[0081]

[0082] (2) Peeling force before electrolyte soaking:

[0083] S1. The first support layer 22, the connecting layer 23, and the second support layer 24 are composited as test objects, and 5000NS tape is affixed to the surfaces of the first support layer 22 and the second support layer 24;

[0084] S2. Then use the Kejian tensile gauge to clamp the 5000NS tapes on both sides of the test object 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.

[0085] 3. Test results and analysis

[0086] The test results of this test case are shown in Table 2.

[0087] It can be seen from Comparative Examples 1 and 2 that the protective tape in the prior art can be applied to thicker aluminum foils, but in the face of the battery industry's pursuit of higher energy density (the thickness of the aluminum foil is reduced from 10μm to 4μm), the anti-drop performance of the protective tape provided in the prior art is significantly reduced, indicating that the existing protective tape cannot meet the more stringent requirements of the battery industry. In practical applications, the peeling force of the connecting layer 23 before soaking in the electrolyte is ≥0.01N / mm to meet the actual use requirements. However, through the peeling force test of the connecting layer 23 of Comparative Examples 1 to 2 before soaking in the electrolyte, it can be seen that although the peeling force of Comparative Examples 1 to 2 can meet the actual use requirements, it does not have good anti-drop performance. This may be because its peeling force before soaking in the electrolyte is too high, which makes it unable to respond quickly to changes in viscosity.

[0088] It can be seen from Examples 1 to 7 and Comparative Example 3 that, on the one hand, the present invention can ensure that the connection layer 23 has a responsive viscosity change without affecting the performance of the battery by regulating the type of the introduced reactive polymer substance. On the second aspect, the present invention can improve the penetration of the electrolyte into the connection layer 23 and accelerate the decrease of the peeling force of the connection layer 23 by regulating the glass transition temperature of the connection layer 23. It can be proved that the battery protection double-sided adhesive provided by the present invention can give the battery good anti-drop performance without affecting the electrical performance of the battery, adapt to the latest development of the battery industry, and improve the market competitiveness of the enterprise itself.

[0089] Specifically, it can be seen from Examples 1 to 4 that using different reactive polymer substances in the connecting layer 23 will affect the anti-drop performance and peeling force performance of the battery, which may be because different reactive polymer substances will affect the penetration rate of the electrolyte into the connecting layer 23. Among them, although Examples 1 to 3 have good anti-drop performance, due to their low peeling force, they may cause sliding problems between the connecting layer 23 and the first supporting layer 22 and the second supporting layer 24 during application.

[0090] Based on Examples 4 to 8, it can be seen that in the connecting layer 23, when the reactive polymer is polymer B, the glass transition temperature of the connecting layer 23 can be adjusted by changing the content or type of the curing agent used in the connecting layer 23. It can be seen from the data that when the glass transition temperature of the connecting layer 23 is within a certain range, it has good anti-drop performance. As the glass transition temperature of the connecting layer 23 decreases, the peeling force of the connecting layer 23 also increases, which helps to improve the sliding problem that may occur between the connecting layer 23 and the first supporting layer 22 and the second supporting layer 24.

[0091] Similarly, by combining the data of Example 1 and Examples 9-10, it can be seen that the type of adhesive substance used in the connecting layer 23 will affect the glass transition temperature of the connecting layer 23, and further affect the sensitivity of the responsive viscosity change of the connecting layer 23. Among them, in the connecting layer 23, polymer A, polymer C, and polymer D can adjust the glass transition temperature of the connecting layer 23 by introducing the mass content and type of adhesive substance. In addition, the type of adhesive substance will also affect the peeling force of the connecting layer 23.

[0092] In addition, the use of a non-full coating method to prepare the connecting layer 23 in the battery protection double-sided tape can not only improve the bonding effect between the adhesive layers, but also improve the penetration of the electrolyte. It can be seen from the data of Example 4, Example 11 and Example 12 that although the area of ​​the connecting layer 23 in Example 4 is higher, its drop resistance can be further improved by designing the structure of the connecting layer 23. In addition, although the effective area of ​​the connecting layer 23 in Example 11 and Example 12 is the same, different settings will affect the peeling force of the connecting layer 23.

[0093] Table 2. Test results of this test case

[0094]

[0095] 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 protection double-sided tape, characterized in that: The battery protection double-sided tape comprises a first adhesive layer, a protective functional layer, and a second adhesive layer which are stacked in sequence; The protective functional layer includes a first supporting layer and a second supporting layer; Furthermore, a connecting layer is provided between the first supporting layer and the second supporting layer, and the glass transition temperature T of the connecting layer is g ≥-25℃; The connecting layer includes a reactive polymer substance, and the mass content of the reactive polymer substance in the connecting layer is not less than 60%; The reactive polymer is selected from at least one polymer of the following A to D, The structural formula of polymer A is The structural formula of polymer B is R is independently selected from at least one of H and CH3; R' is independently selected from at least one of H, CH3, CH2CH3, and CH2(CH2)CH3; The structural formula of polymer C is The polymer D is obtained by polycondensation of an isocyanate having a functionality of at least 2 and a polyol having a functionality of at least 2.

2. The battery protection double-sided tape as claimed in claim 1, characterized in that: The glass transition temperature T of the connecting layer g =-25℃~0℃.

3. The battery protection double-sided tape as claimed in claim 1, characterized in that: The area of ​​the connecting layer independently satisfies a or b; a. The area of ​​the connecting layer is 20 to 70% of the first supporting layer; b. The area of ​​the connecting layer is 20-70% of the area of ​​the second supporting layer.

4. The battery protection double-sided tape according to any one of claims 1 to 3, characterized in that: The connecting layer includes a glue area; In the connecting layer, the number of the adhesive areas is not less than 1; Moreover, the maximum diameter of the adhesive area is 0.1-1 mm; and the concentricity between the adhesive areas is 0.2-2 mm.

5. The battery protection double-sided tape according to any one of claims 1 to 3, characterized in that: A blank portion is also provided between the first supporting layer and the second supporting layer; The blank portion and the connecting layer are in the same plane, and the blank portion and the connecting layer are parallel to the first supporting layer and the second supporting layer; The connection layer is composed of 1 or more rectangular adhesive areas with a width of 1 to 5 mm, and the blank portion is composed of 1 or more rectangular adhesive-free areas with a width of 1 to 5 mm; Furthermore, the rectangular non-glue area and the rectangular glue area are arranged at intervals.

6. The battery protection double-sided tape as claimed in claim 1, characterized in that: The connecting layer further comprises a viscous substance with a mass content not higher than 50%, and the viscous substance comprises at least one of rosin resin, terpene phenol resin and petroleum resin.

7. The battery protection double-sided tape as claimed in claim 1, characterized in that: The connection layer further comprises a curing agent with a mass content of no more than 3%, and the curing agent comprises at least one of amino resin and nitrogen pyridine.

8. The battery protection double-sided tape as claimed in claim 1, characterized in that: Calculated by mass percentage, the first adhesive layer includes 40-80% functional polymer A and 18-50% hydrogenated petroleum resin; The functional polymer A includes at least one of styrene-isoprene-styrene block copolymer, polystyrene-polybutadiene-styrene block copolymer, styrene-butadiene rubber, hydrogenated styrene-polybutadiene-styrene block copolymer, amorphous α-olefin copolymer, polyolefin elastomer, polypropylene and polyisobutylene.

9. The battery protection double-sided tape as claimed in claim 1, characterized in that: Calculated by mass percentage, the second adhesive layer includes 80-95% functional polymer B and 5-20% hydrogenated petroleum resin; Wherein, the functional polymer B includes at least one of styrene-isoprene-styrene block copolymer, polystyrene-polybutadiene-styrene block copolymer, styrene-butadiene rubber, hydrogenated styrene-polybutadiene-styrene block copolymer, amorphous α-olefin copolymer, polyolefin elastomer, polypropylene, and polyisobutylene.

10. The battery protection double-sided tape according to any one of claims 1 to 9, characterized in that: The thickness of the connecting layer is 1 to 3 μm; and / or, the thickness of the first adhesive layer is 2 to 4 μm; And / or, the thickness of the second adhesive layer is 3-6 μm.

11. A battery, characterized in that: The battery comprises a battery cell, a protective layer and the battery protective double-sided tape according to any one of claims 1 to 10; wherein a first adhesive layer is attached to the surface of the battery cell, and an inner surface of the protective layer is attached to a second adhesive layer.

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