Conductive hot melt adhesive and battery

Abstract

The application discloses a conductive hot melt adhesive and a battery. The conductive hot melt adhesive comprises a base and a conductive filler, has a Vicat softening point of 60-130 DEG C, and has a first state and a second state. In the first state, the conductive hot melt adhesive is in a solid state, and in the second state, the conductive hot melt adhesive can soften and flow. The conductive hot melt adhesive is arranged between positive and negative electrode components of the battery. The conductive hot melt adhesive is arranged between the positive and negative electrode components of the battery. When the temperature is lower than the Vicat softening point of the conductive hot melt adhesive, the positive and negative electrode components cannot be conducted through the conductive hot melt adhesive; when the temperature is higher than the Vicat softening point, the conductive hot melt adhesive softens and flows and conducts the positive and negative electrode components, so that the battery can be short-circuited through the flowing conductive hot melt adhesive to realize rapid discharge, the voltage and energy of the battery are rapidly reduced to a safety threshold, accidents such as fire and explosion caused by thermal runaway of the battery can be effectively prevented, and the use safety performance of the battery is improved.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, and more specifically, relates to a conductive hot melt adhesive used in a battery and a battery. Background Technology

[0002] Rechargeable batteries are widely used in many fields due to their advantages such as high energy density and long battery life. When batteries are used under high-power, high-current, or high-temperature conditions, they generate a lot of heat, causing their temperature to rise. If the battery continues to operate under these conditions, its internal chemical system will deteriorate further, leading to thermal runaway and potentially causing fires or explosions. Preventing battery fires or explosions during use and ensuring battery safety has always been a key focus and challenge for battery manufacturers.

[0003] To address these issues, some have proposed incorporating NTC (Negative Temperature Coefficient) devices into the battery cell. These devices could be placed between the positive and negative electrodes, in the empty foil area of ​​the electrode, or embedded in the separator. During high-temperature abuse, the NTC device can discharge the battery, reducing its voltage and energy, thereby mitigating the risk of heat diffusion and improving battery safety. However, NTC devices can cause slow battery discharge and capacity loss. Furthermore, adding NTC devices to the cell introduces additional processes and costs due to the added components, and the devices also occupy internal battery space, affecting energy density. Embedding the NTC device in the separator can also cause a sharp increase in the separator's impedance at room temperature, thus affecting the battery's rate capability and discharge performance. Summary of the Invention

[0004] The purpose of this invention is to provide a conductive hot melt adhesive for use in batteries, which can improve battery safety performance.

[0005] Another object of the present invention is to provide a battery with high safety performance.

[0006] To achieve the aforementioned primary objective, the present invention adopts the following technical solution:

[0007] A conductive hot melt adhesive includes: a matrix and a conductive filler. The matrix is ​​one or more of polyolefins, ethylene and its copolymers, benzoic acid, vanillin, azobenzene, polyesters, polyurethanes, polyamides, and paraffin wax. The conductive filler is at least one of carbon, elemental metal powder, alloy powder, metal oxide powder, and conductive non-metallic compound powder. The Vicat softening point of the conductive hot melt adhesive is 60–130°C. The conductive hot melt adhesive has a first state and a second state. In the first state, the conductive hot melt adhesive is solid, and in the second state, the conductive hot melt adhesive is softenable and flowable.

[0008] Optionally, the matrix of the conductive hot melt adhesive described above is a substance that can transform from a solid to a liquid state at 60–130°C.

[0009] The conductive hot melt adhesive described above may optionally have a viscosity of 2500–8000 cps at 130°C.

[0010] The conductive hot melt adhesive described above may optionally have a resistance of 0.01 to 100 Ω.

[0011] To achieve the second objective mentioned above, the present invention adopts the following technical solution:

[0012] A battery includes a cell, a positive electrode component, a negative electrode component, and the aforementioned conductive hot melt adhesive.

[0013] In the battery described above, optionally, the conductive hot melt adhesive is attached to the surface of the insulating substrate layer.

[0014] In the battery described above, optionally, the conductive hot melt adhesive is attached to the battery cell, the insulating substrate layer is located on the side of the conductive hot melt adhesive away from the battery cell, and there is a gap between the conductive hot melt adhesive and the positive electrode component and / or the negative electrode component.

[0015] In the battery described above, the gap may optionally be 0.1 mm to 100 mm.

[0016] In the battery described above, optionally, the conductive hot melt adhesive is attached to the battery cell, the insulating substrate layer is located on the side of the conductive hot melt adhesive away from the battery cell, the conductive hot melt adhesive is in contact with the positive electrode component and the negative electrode component respectively, and the conductive hot melt adhesive on the insulating substrate layer is discontinuous.

[0017] In the battery described above, optionally, the spacing between the non-continuously arranged conductive hot melt adhesives is 0.1 mm to 100 mm.

[0018] In the battery described above, optionally, the conductive hot melt adhesive is attached to the top or bottom of the battery cell, and the conductive hot melt adhesive and the first and second electrodes of the battery cell are opposite each other on the same side, and there is a gap between the conductive hot melt adhesive and the first and second electrodes.

[0019] Optionally, in the battery described above, the cell is a stacked cell, comprising a first electrode and a second electrode stacked together, with a separator between the first electrode and the second electrode, and empty foil areas at the tails of the first electrode and the second electrode. The outermost layers of the cell are the first electrode and the second electrode, respectively. The conductive hot melt adhesive is attached to the outside of the empty foil area at the tail of the outermost first electrode, and there is a gap between the conductive hot melt adhesive and the empty foil area at the tail of the outermost second electrode.

[0020] In the battery described above, optionally, the conductive hot melt adhesive is attached to the first and second flexible tabs of the battery cell, and the conductive hot melt adhesive is in contact with the first and second flexible tabs respectively.

[0021] Optionally, the battery described above may also include an encapsulation film for encapsulating the battery cell. The first and second tabs of the battery extend from the top sealing edge of the encapsulation film, and the conductive hot melt adhesive is attached to the top sealing edge, with the conductive hot melt adhesive in contact with the first and second tabs respectively.

[0022] As can be seen from the above technical solution, this invention designs a conductive hot melt adhesive for batteries with a Vicat softening point of 60-130℃. The conductive hot melt adhesive is placed between the positive and negative electrode components of the battery, allowing direct bonding and contact between the adhesive and the battery. The conductive hot melt adhesive has two states: solid and softened / flowing. When the temperature is below the Vicat softening point, the adhesive is solid, and the positive and negative electrode components cannot conduct electricity through it. When the temperature is equal to or higher than the Vicat softening point, the adhesive softens and flows, thus conducting electricity between the positive and negative electrode components. The battery can then achieve rapid discharge by short-circuiting through the flowing adhesive, quickly reducing the battery voltage and energy to a safe threshold. This effectively prevents accidents such as fires and explosions caused by thermal runaway, improving battery safety. Furthermore, compared to NTC devices, the conductive hot melt adhesive can be placed at any location on the battery as needed, without increasing the number of battery components, controlling costs, and not occupying too much internal battery space, thus reducing the impact on battery energy density. Attached Figure Description

[0023] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the conductive hot melt adhesive applied to the insulating substrate layer in Embodiment 1 of the present invention;

[0025] Figure 2 This is a schematic diagram of the conductive hot melt adhesive being applied to the end of the core in Embodiment 3 of the present invention;

[0026] Figure 3 This is a schematic diagram of the conductive hot melt adhesive being applied to the empty foil area of ​​the electrode sheet in Embodiment 5 of the present invention;

[0027] Figure 4 This is a schematic diagram of the conductive hot melt adhesive being applied between the positive and negative soft tabs of the battery cell in Embodiment 7 of the present invention;

[0028] Figure 5 This is a schematic diagram of the conductive hot melt adhesive applied to the insulating substrate layer in Embodiment 7 of the present invention;

[0029] Figure 6 This is a schematic diagram of the conductive hot melt adhesive being applied between the positive and negative terminals of the battery in Embodiment 8 of the present invention. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings. In the detailed description of the embodiments of the present invention, for ease of explanation, the drawings illustrating the device structure will be partially enlarged without adhering to the general scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of the present invention. It should be noted that the drawings are in a simplified form and use non-precise scales, solely for the purpose of conveniently and clearly illustrating the embodiments of the present invention. Additionally, in the description of this application, terms such as "first" and "second" are used only to distinguish descriptions and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Terms such as "positive," "negative," "bottom," "upper," and "lower" indicate orientation or positional relationships based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] The conductive hot melt adhesive of this invention is a conductive hot melt adhesive used in batteries. As shown in Figure 1, the conductive hot melt adhesive 2 can be attached to the insulating substrate layer 1. When the insulating substrate layer 1 and the conductive hot melt adhesive 2 are combined and applied to the battery, the insulating substrate layer 1 itself is non-conductive, serving as a skeletal support for the conductive hot melt adhesive 2. The conductive hot melt adhesive 2 is disposed on the insulating substrate layer 1, and the insulating substrate layer 1 utilizes its own wettability with the conductive hot melt adhesive 2 to maintain the conductive hot melt adhesive 2 in a certain initial state and with continuous conductivity.

[0033] The conductive hot melt adhesive 2 comprises a matrix and conductive fillers, which are uniformly mixed. The matrix acts as an adhesive, binding the conductive fillers together to form conductive pathways, thereby achieving conductive connections between areas contacted by the conductive hot melt adhesive 2. The conductive fillers are bound by the matrix. The conductive hot melt adhesive 2 of this invention has a Vicat softening point of 60–130°C and exists in two states: a first state and a second state. The first state is a cured state at room temperature, and the second state is a softened and flowing state at high temperature (when the temperature reaches the Vicat softening point). That is, the conductive hot melt adhesive 2 can soften and flow at temperatures equal to or higher than the Vicat softening point. In both states, the conductive fillers can form conductive pathways under the adhesive effect of the matrix, thus enabling the conductive hot melt adhesive 2 to conduct electricity. The ratio of matrix and conductive filler in conductive hot melt adhesive is adjusted according to the materials of the matrix and conductive filler selected. When different materials are selected for the matrix and conductive filler, the ratio of the two substances will also be different. This invention does not limit the ratio of the two materials. The desired Vicat softening point and the conductivity of conductive hot melt adhesive can be achieved by adjusting the ratio of different materials.

[0034] When conductive hot melt adhesive is used in a battery, preferably, the Vicat softening point of conductive hot melt adhesive 2 is 90–110°C. More preferably, the viscosity of conductive hot melt adhesive 2 at 130°C is 2500–8000 cps.

[0035] In some optional embodiments, the thickness of the conductive hot melt adhesive is 1–100 μm, preferably 4–30 μm. Optionally, the resistance of the conductive hot melt adhesive is 0.01–100 Ω.

[0036] The insulating substrate layer of the present invention is a polymer layer that is not conductive. The material of the insulating substrate layer may be one or more of polyolefins and their modified polymers, polyurethanes, and polyesters. Further, the polyolefin may be one or more of polyethylene, polypropylene, polyvinyl chloride, and polybutene, and the modified polymer of the polyolefin may be one or more of ethylene-acrylic acid modified polymers, propylene-maleic anhydride grafted modified polymers, and propylene-acrylic acid modified polymers.

[0037] The matrix of this invention is a material that can soften and flow at high temperatures, that is, it can transform from a solid to a liquid state at 60–130°C. Optionally, the matrix may be one or more of polyolefins, ethylene and its copolymers, benzoic acid, vanillin, azobenzene, polyesters, polyurethanes, polyamides, and paraffin wax; furthermore, the polyolefin may be polyethylene or polypropylene; the olefin copolymer may be ethylene-vinyl acetate, ethylene-acrylic acid copolymer, propylene-vinyl acetate, propylene-acrylic acid copolymer, butene-vinyl acetate, etc.

[0038] The conductive filler of this invention can be at least one of carbon, elemental metal powder, alloy powder, metal oxide powder, and conductive non-metallic compound powder. Further, the carbon can be one or more of conductive carbon black, carbon nanotubes, graphene, graphite, or graphite nanosheets, wherein the conductive carbon black can be one or more of acetylene black, superconducting carbon black N293, highly conductive carbon black N472, ultra-high conductive carbon black BP2000, and Japanese superconducting carbon black CB3100. The elemental metal can be at least one of gold, silver, platinum, copper, aluminum, nickel, zinc, and tin. The alloy can be at least one of brass, cupronickel, bronze, silver-aluminum alloy, copper-silver alloy, nickel-aluminum alloy, silver-plated copper, silver-plated aluminum, and silver-plated zinc. The metal oxide can be aluminum oxide, copper oxide, nickel oxide, zinc oxide, calcium oxide, rare earth metal oxide, or a composite oxide of two or more metals. The conductive non-metallic compound can be at least one of carbon compound, silicon compound, nitrogen compound, selenium compound, and carbonitridium compound. The crystal grain size D1 of the conductive filler is: 0.01μm≤D1≤20μm.

[0039] The conductive hot melt adhesive of this invention can be applied to batteries such as secondary lithium-ion batteries or lithium metal batteries. Batteries typically include a cell, a positive electrode component, and a negative electrode component. The cell can be a stacked cell or a wound cell. In use, the conductive hot melt adhesive is applied to an insulating substrate layer, with the adhesive side facing up, and then attached to the cell. The conductive hot melt adhesive is in direct contact with the cell. The conductive hot melt adhesive can be applied at any position on the cell, as long as it is close to the positive and negative electrode components. A gap is maintained between the conductive hot melt adhesive and the positive and / or negative electrode components, or the conductive hot melt adhesive is not discontinuously disposed between the positive and negative electrode components. Therefore, in the first state, the conductive hot melt adhesive does not form a conductive connection between the positive and negative electrode components. However, at high temperatures, the conductive hot melt adhesive softens and flows in the second state, thereby enabling the conductive hot melt adhesive to conduct electricity between the positive and negative electrode components, allowing the battery to discharge through the conductive hot melt adhesive.

[0040] The positive and negative electrode components of a battery can be positive and negative tabs, positive and negative electrode plates, or positive and negative current collectors, etc. For example, conductive hot melt adhesive can be placed near the positive and negative tabs, positive and negative electrode plates, positive and negative current collectors, tabs and plates with opposite polarity, tabs and current collectors with opposite polarity, or current collectors and plates with opposite polarity. In specific applications, conductive hot melt adhesive can be attached to the top or bottom of the battery cell (e.g., Figure 2 As shown), it can also be attached to the empty foil at the end of the electrode sheet of the battery cell (such as...). Figure 3 As shown), it can also be attached between the positive and negative soft tabs of the battery cell (such as...). Figure 4 As shown in Figure 6, the conductive hot melt adhesive can be applied between the positive and negative terminals of the battery. The spacing between the discontinuous conductive hot melt adhesives can be 0.1mm to 100mm, preferably between 0.5mm and 10mm; the gap between the conductive hot melt adhesive and the positive and negative electrode components can be 0.1mm to 100mm, preferably between 0.5mm and 10mm. This can prevent the conductive hot melt adhesive from short-circuiting the positive and negative electrode components when the battery temperature is below the Vicat softening point of the conductive hot melt adhesive, and can also allow the positive and negative electrode components of the battery to be connected through the softening flow of the conductive hot melt adhesive at high temperatures, thus achieving discharge.

[0041] The present invention will be further described below through specific embodiments. Unless otherwise specified, the reagents, materials and instruments used in the following description are all conventional reagents, materials and instruments, which are commercially available, and the reagents involved can also be synthesized by conventional synthetic methods.

[0042] Example 1

[0043] The conductive hot melt adhesive in this embodiment is prepared by esterification and polycondensation. First, the matrix is ​​esterified, and then conductive filler is added to carry out a reduced-pressure polycondensation reaction to obtain the conductive hot melt adhesive. When used, the conductive hot melt adhesive can be attached to the insulating substrate layer.

[0044] The conductive hot melt adhesive in this embodiment is prepared by the following method:

[0045] (1) Long-chain fatty diacid, medium-chain fatty diacid and branched diol with 8 or less carbon atoms are mixed in the following mass ratio: 20-30: 20-30: 15-30. The first esterification reaction is carried out under the action of Sb(AC)3 catalyst and under the protection of nitrogen or argon atmosphere. The reaction temperature is between 190 and 210°C. The reaction is stopped when the amount of water produced reaches more than 96% of the theoretical amount.

[0046] (2) Add the following to the system in step (1): 10-15 parts by mass of terephthalic acid, 5-10 parts by mass of dimer acid, 5-8 parts by mass of hexamethylenediamine, 10-15 parts by mass of butanediol and 5-8 parts by mass of glycerol, and carry out a second esterification reaction at a reaction temperature of 190-210℃.

[0047] (3) Add the following to the system in step (2): 3-8 parts by weight of thermoplastic elastomer, 1-6 parts by weight of coupling agent, 1-5 parts by weight of heat stabilizer, 10-30 parts by weight of conductive copper powder and 10-30 parts by weight of CNT carbon nanotubes, 1-3 parts by weight of copper oxide powder and 1-3 parts by weight of titanium carbide. Continue the reduced pressure polycondensation reaction for 30-40 minutes. After the polycondensation is completed, discharge the material to obtain conductive hot melt adhesive.

[0048] The obtained conductive hot melt adhesive and propylene-maleic anhydride grafted modified polymer were cast into a 15μm film by a melt extruder at a thickness ratio of 3:1 to obtain a conductive hot melt adhesive attached to an insulating substrate layer.

[0049] Example 2

[0050] The conductive hot melt adhesive in this embodiment is prepared by a melt reaction. First, the matrix is ​​added to a melt reaction furnace and stirred evenly. Then, conductive filler is added to the melt and stirred evenly to obtain the conductive hot melt adhesive. When in use, the conductive hot melt adhesive is attached to the insulating substrate layer.

[0051] The conductive hot melt adhesive in this embodiment is prepared by the following method:

[0052] (1) Weigh the following substances according to the following mass parts: 20-40 parts of ethylene-ethyl acetate, 20-40 parts of ethylene-acrylic acid copolymer, 10-20 parts of xylene, 5-10 parts of coal-based synthetic wax, 5-15 parts of copper powder, 5-10 parts of carbon nanotubes, 10-20 parts of silane coupling agent, 5-10 parts of silicate, 3-8 parts of polypropylene wax, 1-5 parts of thiobisphenol type antioxidant, and 1-5 parts of heat stabilizer.

[0053] (2) Add ethylene-ethyl acetate, ethylene-acrylic acid copolymer, thiobisphenol type antioxidant, xylene, and coal-based synthetic wax into a melting reactor and stir until homogeneous;

[0054] (3) Place copper powder, carbon nanotubes, silane coupling agent and silicates in a container, stir thoroughly, filter and dry.

[0055] (4) Add the product obtained in step (3) to the melt in step (2) and stir continuously until uniform to obtain conductive hot melt adhesive.

[0056] The obtained conductive hot melt adhesive and propylene-acrylic acid copolymer were co-extruded into a 30μm film by a melt extruder at a thickness ratio of 1:1, resulting in a conductive hot melt adhesive attached to an insulating substrate layer.

[0057] The synthesis methods provided in Examples 1 and 2 are merely examples of the conductive hot melt adhesive preparation method of the present invention. The conductive hot melt adhesive of the present invention is not limited to the above two preparation methods. When different raw materials are selected, appropriate preparation methods can be adopted accordingly, which will not be listed one by one here.

[0058] Example 3

[0059] The battery in this embodiment includes a wound cell, which includes a positive electrode 100 (first electrode), a negative electrode 101 (second electrode), and a separator 106 disposed between the positive electrode 100 and the negative electrode 101. Figure 2 As shown, in this embodiment, the conductive hot melt adhesive obtained in Example 1, attached to the insulating substrate layer, is thermally bonded to the top of the wound battery cell (the end of the battery cell with the tab is the top, and the other end of the battery cell opposite to the end with the tab is the tail). The conductive hot melt adhesive 2 and the positive electrode 100 and negative electrode 101 of the battery cell are on the same side with the edges of the conductive hot melt adhesive, and there is a gap between the conductive hot melt adhesive 2 and the positive electrode 100 and negative electrode 101. The insulating substrate layer 1 is located on the side of the conductive hot melt adhesive 2 away from the battery cell. In the first state, because there is a gap between the conductive hot melt adhesive 2 and the positive electrode 100 and negative electrode 101 of the battery cell, the conductive hot melt adhesive 2 cannot conduct electricity between the positive electrode 100 and negative electrode 101, which can prevent the battery from discharging. The battery in this embodiment has a capacity of 5500mAh and a voltage of 4.55V.

[0060] Example 4

[0061] In this embodiment, the conductive hot melt adhesive prepared in Example 2 is thermally bonded to the tail end of the wound battery cell. The conductive hot melt adhesive and the positive and negative electrode sheets of the battery cell are positioned on the same side opposite to each other, with gaps between them. The insulating substrate layer is located on the side of the conductive hot melt adhesive away from the battery cell. In the first state, there are gaps between the conductive hot melt adhesive and the positive and negative electrode sheets of the battery cell, preventing conductivity between them. The battery in this embodiment has a capacity of 5500mAh and a voltage of 4.55V.

[0062] Example 5

[0063] The battery of this embodiment includes a stacked cell, which includes a positive electrode 100 and a negative electrode 101 stacked together. A separator 106 is disposed between the positive electrode 100 and the negative electrode 101. Both the positive electrode 100 and the negative electrode 101 have empty foil areas without active material coating. The outermost layers of the cell are the positive electrode 100 and the negative electrode 101. In this embodiment, the conductive hot melt adhesive prepared in Example 1 is applied to the empty foil area at the end of the stacked cell, and the cell is finished with conductive hot melt adhesive. Figure 3 As shown, in this embodiment, conductive hot melt adhesive 2 is attached to the outside of the empty aluminum foil 100a at the tail of the outermost positive electrode 100 of the battery cell, and the outside of the empty copper foil 101a at the tail of the outermost negative electrode 101 of the battery cell is also covered (not shown). The insulating substrate layer 1 is located on the side of the conductive hot melt adhesive 2 away from the electrode (battery cell). There is a gap between the conductive hot melt adhesive 2 and the empty foil area of ​​the outermost negative electrode 101 of the battery cell, so that in the first state, the conductive hot melt adhesive 2 cannot conduct electricity between the positive electrode 100 and the negative electrode 101. The battery of this embodiment has a capacity of 10000mAh and a voltage of 4.35V.

[0064] Example 6

[0065] The cell structure in this embodiment is the same as that in Embodiment 5, except that in this embodiment, the conductive hot melt adhesive prepared in Embodiment 2 is applied to the empty foil at the end of the stacked cell for finishing. The conductive hot melt adhesive wraps the empty aluminum foil at the end of the positive electrode and the empty copper foil at the end of the negative electrode, with gaps between the adhesive and the empty aluminum and copper foils. The insulating substrate layer is located on the side of the conductive hot melt adhesive away from the electrode. In the first state, the conductive hot melt adhesive cannot conduct electricity between the positive and negative electrode. The battery in this embodiment has a capacity of 10000mAh and a voltage of 4.42V.

[0066] Example 7

[0067] The battery in this embodiment includes a wound cell. In this embodiment, the conductive hot melt adhesive obtained in Example 2 is applied to the positive electrode soft tab (first soft tab) and the negative electrode soft tab (second soft tab) of the wound cell. Figure 4 As shown, conductive hot melt adhesive is applied to the positive electrode tab 102 and the negative electrode tab 103 of the battery cell. The conductive hot melt adhesive is in contact with the positive and negative electrode tabs, respectively, and the insulating substrate layer 1 is on the side of the conductive hot melt adhesive away from the electrode tabs. Figure 5As shown, the conductive hot melt adhesive 2 on the insulating substrate layer 1 is discontinuous, with a 0.5mm gap a between the discontinuous conductive hot melt adhesive 2 sections. This gap a separates the section of conductive hot melt adhesive 2 in contact with the positive electrode tab and the section in contact with the negative electrode tab, thus preventing the conductive hot melt adhesive 2 from conducting through the positive electrode tab 102 and the negative electrode tab 103 in the first state. The battery in this embodiment has a capacity of 4500mAh and a voltage of 4.48V.

[0068] Example 8

[0069] In this embodiment, the conductive hot melt adhesive prepared in Example 1 is applied to the positive tab (first tab) and negative tab (second tab) of the battery that protrude from the encapsulation film after the battery cell is encapsulated with the encapsulation film. Figure 5 As shown, after the wound battery cell is encapsulated with an aluminum-plastic film, the positive electrode 10 and negative electrode 20 of the battery are led out from the top sealing edge 11 of the aluminum-plastic film (the sealing edge on the side where the electrode leads out of the encapsulation film is the top sealing edge). Conductive hot melt adhesive is attached to the top sealing edge 11 between the positive electrode 10 and the negative electrode 20. Conductive hot melt adhesive 2 is in contact with the positive electrode 10 and the negative electrode 20 respectively. The insulating substrate layer is on the side of the conductive hot melt adhesive 2 away from the top sealing edge (battery cell). The conductive hot melt adhesive 2 on the insulating substrate layer is discontinuous, and the conductive hot melt adhesive 2 has a 2mm gap a, so that in the first state, the conductive hot melt adhesive 2 cannot conduct electricity between the positive electrode 10 and the negative electrode 20. The battery in this embodiment has a capacity of 4500mAh and a voltage of 4.48V.

[0070] Comparative Example 1

[0071] The battery in Comparative Example 1 is the same as the battery in Example 3, but the conductive hot melt adhesive of the present invention is not used in the battery.

[0072] Comparative Example 2

[0073] The battery in Comparative Example 2 is the same as the battery in Example 5, but the conductive hot melt adhesive of the present invention is not used in the battery.

[0074] Comparative Example 3

[0075] The battery in Comparative Example 3 is the same as the battery in Example 6, but the conductive hot melt adhesive of the present invention is not used in the battery.

[0076] Comparative Example 4

[0077] The battery in Comparative Example 4 is the same as the battery in Example 7, but the conductive hot melt adhesive of the present invention is not used in the battery.

[0078] Comparative Example 5

[0079] The battery in Comparative Example 5 is the same as the battery in Example 8, but the conductive hot melt adhesive of the present invention is not used in the battery.

[0080] The batteries of Examples 3-8 and Comparative Examples 1-5 were subjected to high-temperature external short-circuit test according to Clause 6.2 of GB / T31241-2014, overcharge test according to Clause 6.3 of GB / T31241-2014, forced discharge test according to Clause 6.4 of GB / T31241-2014, and thermal abuse test according to Clause 7.8 of GB / T31241-2014. The test results are shown in Table 1.

[0081] Table 1

[0082]

[0083]

[0084] As can be seen from the results in Table 1, the safety performance of the battery is significantly improved after using the conductive hot melt adhesive of the present invention. This is because the conductive hot melt adhesive of the present invention is disposed between the positive and negative electrode components of the battery in a way that maintains a gap, or the conductive hot melt adhesive is disposed between the positive and negative electrode components of the battery in a discontinuous way. Under normal conditions, the conductive hot melt adhesive is similar to conventional insulating adhesive and does not conduct electricity between the positive and negative electrode components of the battery. However, when the battery encounters high current, overcharging, over-discharging, thermal abuse, etc., the high-temperature softening and flowing characteristics of the conductive hot melt adhesive can conduct electricity between the positive and negative electrode components it is connected to, thereby discharging the battery and allowing the battery voltage and energy to be quickly reduced to the safety threshold. This effectively prevents accidents such as fire and explosion caused by thermal runaway of the battery and improves the safety performance of the battery.

[0085] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the present invention.

Claims

1. A battery, comprising a cell, a positive electrode component, a negative electrode component, a conductive hot melt adhesive, and an insulating substrate layer, wherein the conductive hot melt adhesive is attached to the insulating substrate layer, the conductive hot melt adhesive is bonded to the cell, the insulating substrate layer is located on the side of the conductive hot melt adhesive away from the cell, a gap exists between the conductive hot melt adhesive and the positive electrode component and / or the negative electrode component, or the conductive hot melt adhesive is in contact with the positive electrode component and the negative electrode component respectively, and the conductive hot melt adhesive on the insulating substrate layer is discontinuous; the conductive hot melt adhesive comprises: Matrix and conductive filler; The matrix is ​​one or more of polyolefins, ethylene copolymers, benzoic acid, vanillin, azobenzene, polyesters, polyurethane, polyamide, and paraffin wax, and the conductive filler is at least one of carbon, elemental metal powder, alloy powder, metal oxide powder, and conductive non-metallic compound powder. The conductive hot melt adhesive has a Vicat softening point of 60–130°C. The conductive hot melt adhesive has a first state and a second state. In the first state, the conductive hot melt adhesive is solid and does not form a conductive connection between the positive electrode component and the negative electrode component. In the second state, the conductive hot melt adhesive can soften and flow, and the conductive hot melt adhesive conducts electricity between the positive electrode component and the negative electrode component.

2. The battery as described in claim 1, characterized in that: The matrix is ​​a substance that can transform from a solid to a liquid state at 60–130°C.

3. The battery as described in claim 1, characterized in that: The viscosity of the conductive hot melt adhesive at 130°C is 2500–8000 cps.

4. The battery as described in claim 1, characterized in that: The resistance of the conductive hot melt adhesive is 0.01 to 100 Ω.

5. The battery as described in claim 1, characterized in that: The gap is 0.1mm to 100mm.

6. The battery as described in claim 1, characterized in that: The interval between the discontinuously arranged conductive hot melt adhesives is 0.1mm to 100mm.

7. The battery as described in claim 1, characterized in that: The conductive hot melt adhesive is attached to the top or tail of the battery cell. The conductive hot melt adhesive and the first and second electrodes of the battery cell are located on the same side with the edges of the conductive hot melt adhesive, and there is a gap between the conductive hot melt adhesive and the first and second electrodes.

8. The battery as described in claim 1, characterized in that: The battery cell is a stacked battery cell, comprising a first electrode and a second electrode stacked together, with a separator between the first electrode and the second electrode, and empty foil areas at the tails of the first electrode and the second electrode. The outermost layers of the battery cell are the first electrode and the second electrode, respectively. The conductive hot melt adhesive is attached to the outside of the empty foil area at the tail of the outermost first electrode, and there is a gap between the conductive hot melt adhesive and the empty foil area at the tail of the outermost second electrode.

9. The battery as claimed in claim 1, characterized in that: The conductive hot melt adhesive is attached to the first and second soft tabs of the battery cell, and the conductive hot melt adhesive is in contact with the first and second soft tabs respectively.

10. The battery as claimed in claim 1, characterized in that: It also includes an encapsulation film for packaging the battery cell, with the first and second tabs of the battery extending from the top sealing edge of the encapsulation film, and the conductive hot melt adhesive being attached to the top sealing edge, with the conductive hot melt adhesive in contact with the first and second tabs respectively.

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