Heating film and preparation method thereof, battery module, battery pack and electric equipment

Abstract

The invention provides a heating film and a preparation method thereof, a battery module, a battery pack and electric equipment, the heating film comprises a first insulating layer, a metal layer, a heating layer and a second insulating layer, the first insulating layer is formed on a first side of the metal layer, the heating layer is formed on a second side of the metal layer, and the heating layer is electrically connected with the metal layer; wherein the first side and the second side are two opposite sides in the thickness direction of the metal layer; the second insulating layer is formed on the side, away from the metal layer, of the heating layer. The metal layer is further connected with a wire. Wherein the first insulating layer and the second insulating layer are photocuring coatings. The high-temperature and high-humidity resistance of the heating film is improved.

Description

Technical Field

[0001] The present application relates to the technical field of heating films, and in particular to a heating film and a preparation method thereof, a battery module, a battery pack and electrical equipment. Background Art

[0002] In view of the fact that the battery may fail to charge or have low charging and discharging efficiency when working in a low temperature environment, the relevant technology usually configures a device for heating the battery. The device for heating the battery can generally use a heating film to achieve heating, among which the positive temperature coefficient (PTC) heating film (hereinafter referred to as the heating film) is widely used due to its advantages such as softness and bendability, high heating rate, and self-temperature control.

[0003] However, the heating film in the related art has the problem of poor resistance to high temperature and high humidity. Summary of the invention

[0004] In order to overcome the above-mentioned defects under the related art, the purpose of the present application is to provide a heating film and its preparation method, a battery module, a battery pack and electrical equipment. The present application is conducive to improving the high temperature and high humidity resistance of the heating film.

[0005] On the one hand, the present application provides a heating film, comprising a first insulating layer, a metal layer, a heating layer, and a second insulating layer, wherein the first insulating layer is formed on a first side of the metal layer, the heating layer is formed on a second side of the metal layer, and the heating layer is electrically connected to the metal layer; wherein the first side and the second side are opposite sides in a thickness direction of the metal layer; the second insulating layer is formed on a side of the heating layer away from the metal layer, and the metal layer is further connected to a wire;

[0006] Wherein, the first insulating layer and the second insulating layer are both photocurable coatings.

[0007] In a possible implementation, the photocurable coating includes a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

[0008] In a possible implementation, a third insulating layer is further included, and the third insulating layer is located between the metal layer and the heating layer; the third insulating layer is provided with a groove, and the groove is connected to the metal layer to expose part of the metal layer, and the heating layer is electrically connected to the metal layer through the groove.

[0009] In a possible implementation manner, the third insulating layer includes a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

[0010] In a possible implementation manner, the thickness of the first insulating layer, the second insulating layer and the third insulating layer are all 80-150 μm.

[0011] In a possible implementation manner, the dielectric strengths of the first insulating layer, the second insulating layer, and the third insulating layer are all greater than or equal to 10 KV / mm.

[0012] In a possible implementation, the surface resistivity of the first insulating layer, the second insulating layer and the third insulating layer are all greater than or equal to 1*10 12 Ω·cm.

[0013] In a possible implementation, the water vapor transmission rates of the first insulating layer, the second insulating layer and the third insulating layer are all less than or equal to 1 g / m 2 / day.

[0014] In a possible implementation manner, the metal layer includes an aluminum foil layer, a rolled copper layer, or an electrolytic copper layer.

[0015] In a possible implementation manner, the thickness of the metal layer is 20-80 μm, and the volume resistivity of the metal layer is ≤0.001 Ω·cm.

[0016] In a possible implementation manner, the sum of the thicknesses of the metal layer, the first insulating layer, and the third insulating layer is 100-180 μm.

[0017] In a possible implementation, the heating layer includes a positive temperature coefficient heating layer.

[0018] In a possible implementation, the positive temperature coefficient heating layer includes a polymer matrix and a conductive filler, the polymer matrix includes polyethylene, polypropylene or polyvinyl chloride, and the conductive filler includes carbon black, graphite, copper powder, silver powder, tin oxide or zinc oxide.

[0019] In a possible implementation manner, the metal layer is electrically connected to the wire via a conductive adhesive layer, and a fourth insulating layer is further provided at the connection position between the metal layer and the wire.

[0020] In a possible implementation, the conductive adhesive layer includes a two-component epoxy resin conductive adhesive layer or a two-component acrylate conductive adhesive layer, the volume resistivity of the conductive adhesive layer is ≤0.001Ω·cm, and the contact resistance between the conductive adhesive layer and the metal layer or the wire is ≤0.05Ω.

[0021] In a possible implementation manner, the fourth insulating layer includes a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

[0022] In another aspect, the present application provides a method for preparing a heating film, comprising:

[0023] providing a metal layer;

[0024] Preparing a first insulating layer on a first side of the metal layer;

[0025] A heat generating layer is prepared on the second side of the metal layer, and the heat generating layer is electrically connected to the metal layer; wherein the first side and the second side are opposite sides in the thickness direction of the metal layer;

[0026] A second insulating layer is prepared on a side of the heat generating layer away from the metal layer;

[0027] electrically connecting a wire to the metal layer;

[0028] Wherein, the first insulating layer and the second insulating layer are both photocurable coatings.

[0029] In a possible implementation, the photocurable coating includes a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

[0030] In a possible implementation, the first insulating layer is formed on the first side of the metal layer by spraying or inkjet printing an insulating material and then curing it under light;

[0031] And / or, the second insulating layer is formed on the side of the heating layer away from the metal layer by spraying or inkjet printing an insulating material and then curing it under light.

[0032] In a possible implementation, the method further includes:

[0033] A third insulating layer is prepared on the second side of the metal layer, and the third insulating layer is located between the metal layer and the heating layer; wherein the third insulating layer is formed with a groove, the groove is connected to the metal layer to expose part of the metal layer, and the heating layer is electrically connected to the metal layer through the groove.

[0034] In a possible implementation manner, the third insulating layer includes a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

[0035] In a possible implementation manner, preparing a third insulating layer on the second side of the metal layer includes:

[0036] Covering the second side of the metal layer with a shielding layer;

[0037] Spraying insulating material onto the metal layer covered with the shielding layer and curing it by light;

[0038] The shielding layer is removed to form the third insulating layer.

[0039] In a possible implementation manner, preparing a heating layer on the second side of the metal layer includes:

[0040] Printing a heating layer paste on a side of the third insulating layer away from the metal layer;

[0041] The printed heating layer slurry is baked and cured to form the heating layer.

[0042] In a possible implementation, the heating layer includes a positive temperature coefficient heating layer.

[0043] In a possible implementation, the positive temperature coefficient heating layer includes a polymer matrix and a conductive filler, the polymer matrix includes polyethylene, polypropylene or polyvinyl chloride, and the conductive filler includes carbon black, graphite, copper powder, silver powder, tin oxide or zinc oxide.

[0044] In a possible implementation, the baking temperature of the heating layer slurry is 80-150° C.; the baking time of the heating layer slurry is 15-30 min.

[0045] In a possible implementation, the second insulating layer is formed on the side of the heat generating layer away from the third insulating layer by spraying or inkjet printing an insulating material and then curing it through light.

[0046] In a possible implementation manner, electrically connecting the wire to the metal layer includes:

[0047] Coating a conductive adhesive layer at a position of the metal layer for connecting the conductive wire, and bonding the conductive wire to the conductive adhesive layer;

[0048] A fourth insulating layer is coated on the bonding position between the metal layer and the wire.

[0049] In a possible implementation, the conductive adhesive layer includes a two-component epoxy resin conductive adhesive layer or a two-component acrylate conductive adhesive layer, the volume resistivity of the conductive adhesive layer is ≤0.001Ω·cm, and the contact resistance between the conductive adhesive layer and the metal layer or the wire is ≤0.05Ω.

[0050] In a possible implementation manner, the fourth insulating layer includes a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

[0051] On the other hand, the present application provides a battery module, comprising any heating film as described above.

[0052] On the other hand, the present application provides a battery pack comprising at least one battery module as described above.

[0053] On the other hand, the present application provides an electrical device, including the battery pack as described above.

[0054] The present application provides a heating film and a preparation method thereof, a battery module, a battery pack and an electrical device. The heating film includes a first insulating layer, a metal layer, a heating layer and a second insulating layer. The first insulating layer is formed on the first side of the metal layer, and the heating layer is formed on the second side of the metal layer. The heating layer is electrically connected to the metal layer; wherein the first side and the second side are opposite sides in the thickness direction of the metal layer; the second insulating layer is formed on the side of the heating layer away from the metal layer, and the metal layer is also connected to a wire; wherein the first insulating layer and the second insulating layer are both photocured coatings. The present application forms a first insulating layer on the first side of the metal layer, and forms a second insulating layer on one side of the heating layer. The first insulating layer and the second insulating layer are both selected as photocured coatings. Since the water vapor permeability of the photocured coating is relatively low, the high temperature and high humidity resistance of the heating film is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the following is a brief introduction to the drawings required for use in the embodiments or the related technical descriptions. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0056] Figure 1 It is a simplified structural diagram of a heating film in the related art;

[0057] Figure 2 A simplified structural diagram of a heating film provided in one embodiment of the present application;

[0058] Figure 3 A flow chart for preparing a heating film according to an embodiment of the present application.

[0059] Reference numerals:

[0060] 11- bottom floor;

[0061] 12-surface layer;

[0062] 13-PTC heating layer;

[0063] 14-current carrying bar;

[0064] 15- second adhesive layer;

[0065] 16- conductive thread;

[0066] 100-metal layer;

[0067] 200-third insulating layer;

[0068] 300-heating layer;

[0069] 400- second insulating layer;

[0070] 500-wire. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0072] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0073] As described in the background technology, the heating film in the related art solution has problems such as poor resistance to high temperature and humidity and complex preparation process. Figure 1 This is a simplified diagram of the structure of the heating film in the related technology. Please refer to Figure 1 In the related art, the heating film includes a bottom layer 11 and a surface layer 12 that are arranged relatively, and a PTC heating layer 13 and a current-carrying bar 14 are also arranged between the bottom layer 11 and the surface layer 12. Both the bottom layer 11 and the surface layer 12 can be a polyimide film (PI) layer or a polyethylene terephthalate film (PET) layer. The bottom layer 11 is bonded to the current-carrying bar 14 and the first side of the PTC heating layer 13 through a first adhesive layer (not shown in the figure), and the surface layer 12 is bonded to the second side of the PTC heating layer 13 through a second adhesive layer 15. The current-carrying bar 14 is electrically connected to the conductive wire 16, and is connected to an external power supply device through the conductive wire 16.

[0074] Since the bottom layer 11 and the surface layer 12 are both polyimide film layers or polyethylene terephthalate film layers, and the thickness is generally less than or equal to 150 μm, the water vapor transmission rate is generally greater than 50 g / m 2 / day, the PTC heating layer 13 is easily aged by the infiltrated moisture under high temperature conditions, and the heating film has poor resistance to high temperature and high humidity.

[0075] Furthermore, since the bottom layer 11 and the surface layer 12 are both polyimide film layers or polyethylene terephthalate film layers, the corresponding first adhesive layer and the second adhesive layer 15 need to be configured to be bonded to the PTC heating layer 13 and the current carrying bar 14. The first adhesive layer and the second adhesive layer 15 are usually made of hot melt adhesive, which needs to be heated before the adjacent layers can be bonded together. Therefore, the preparation process is relatively complicated, which makes the quality control of the heating film more difficult and the yield is low.

[0076] The current carrying bar 14 is generally formed by printing silver paste into a specific pattern on the surface of the surface layer 12 and then baking and curing it at a baking temperature of 80 to 150° C. for 5 to 30 minutes. The preparation process of the current carrying bar 14 is complex and time-consuming.

[0077] When installing the current-carrying bar 14 and the conductive wire 16, it is necessary to first use a laser to remove the surface film at the connection of the conductive wire 16, and then rivet the connection of the conductive wire 16 and use tin wire to heat and melt to weld the conductive wire 16 and the rivet together. The location where the conductive wire 16 is welded also needs to be hot-pressed with a layer of insulating material to play an insulating protection role. The insulating material is generally composed of silicone skin and hot melt adhesive film, and the hot pressing conditions are generally a temperature of 160-200°C, a pressure of 0.1-0.25MPa, and a hot pressing time of 95-105s. The installation process is complicated, time-consuming and labor-intensive, and the insulating material needs to be thermally cured, which consumes a lot of energy, increasing the production cost of the heating film.

[0078] In view of this, the embodiments of the present application aim to provide a heating film and a preparation method thereof, a battery module, a battery pack and an electrical device, by forming a first insulating layer on the first side of the metal layer, forming a second insulating layer on one side of the heating layer, and the first insulating layer and the second insulating layer are both selected as photocurable coatings. Since the water vapor permeability of the photocurable coating is relatively low, the high temperature and high humidity resistance of the heating film is improved.

[0079] The contents of the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings so that those skilled in the art can understand the contents of the present application in more detail.

[0080] Figure 2 A simplified structural diagram of a heating film provided in one embodiment of the present application.

[0081] Please refer to Figure 2, this embodiment provides a heating film, including a first insulating layer (not shown in the figure), a metal layer 100, a heating layer 300 and a second insulating layer 400. The first insulating layer is formed on the first side of the metal layer 100. For example, the first insulating layer can be formed on the metal layer 100 by spraying or inkjet printing. The heating layer 300 is formed on the second side of the metal layer 100 and is electrically connected to the metal layer 100. Among them, the first side and the second side are opposite sides in the thickness direction of the metal layer 100. For example, the heating layer 300 can be made of PTC material, and the heating layer 300 can be formed on the metal layer 100 by printing, baking and other processes. The second insulating layer 400 is formed on the side of the heating layer 300 away from the metal layer 100. For example, the second insulating layer 400 can also be formed on the heating layer 300 by spraying or inkjet printing. The metal layer 100 is also connected to a wire 500, which is used to connect to an external power source to supply power to the metal layer 100. When the metal layer 100 is energized, the heating layer 300 connected thereto can generate heat, thereby achieving the purpose of heating.

[0082] In this embodiment, the first insulating layer and the second insulating layer 400 are both light-cured flexible coatings. Since the water vapor permeability of the light-cured coatings is low, the high temperature and high humidity resistance of the heating film is improved. For example, the light-cured flexible coating can be a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

[0083] From the above description, it can be known that in this embodiment, a first insulating layer is formed on the first side of the metal layer 100, and a second insulating layer 400 is formed on one side of the heating layer 300, and the first insulating layer and the second insulating layer 400 are both photocurable flexible coatings. Since the water vapor permeability of the photocurable coating is relatively low, the high temperature and high humidity resistance of the heating film is improved.

[0084] Please continue to refer to Figure 2 , this embodiment further includes a third insulating layer 200, which is formed on the second side of the metal layer 100 and is located between the metal layer 100 and the heating layer 300. The third insulating layer 200 is provided with a groove, and the groove is connected to the metal layer 100 to expose a portion of the metal layer 100, and the heating layer 300 is electrically connected to the metal layer 100 through the groove. Exemplarily, the third insulating layer 200 can also be formed on the metal layer 100 by spraying or inkjet printing; a shielding layer can be used to shield a portion of the metal layer 100 before preparing the third insulating layer 200, and then the shielding layer can be removed after the third insulating layer 200 is prepared to form a groove.

[0085] The third insulating layer 200 of this embodiment exposes part of the metal layer 100 through the grooves, so as to act as a current-carrying bar and be electrically connected to the heating layer 300, which is beneficial to reducing the number of parts of the heating film and simplifying the manufacturing process.

[0086] Optionally, the third insulating layer 200 of the present embodiment includes a polyurethane-modified acrylate layer or a silicone-modified acrylate layer, so that it has a lower water vapor permeability to further prevent external water vapor from corroding the internal heating layer 300 .

[0087] Optionally, in this embodiment, the thickness of the first insulating layer, the second insulating layer 400 and the third insulating layer 200 can be selected to be 80-150 μm, so as to ensure that the first insulating layer, the third insulating layer 200 and the second insulating layer 400 can have better performance.

[0088] The dielectric strength of the first insulating layer, the second insulating layer 400 and the third insulating layer 200 are all greater than or equal to 10 KV / mm, thereby ensuring that the heating film has good insulation performance and a strong voltage bearing capacity, so that the heating film can work stably for a long time.

[0089] The surface resistivity of the first insulating layer, the second insulating layer 400 and the third insulating layer 200 is greater than or equal to 1*10 12 Ω·cm, thereby reducing the current passing capacity of the heating film surface and ensuring its insulation performance; a higher surface resistivity can also ensure that the heating film has better corrosion resistance and wear resistance, which is beneficial to prolonging its service life.

[0090] The water vapor transmission rates of the first insulating layer, the second insulating layer 400 and the third insulating layer 200 are all less than or equal to 1 g / m 2 / day, thereby preventing the heating layer in the heating film from being corroded and ensuring the stability of the heating film when working in a high temperature and high humidity environment.

[0091] The metal layer 100 of this embodiment includes an aluminum foil layer, a rolled copper layer or an electrolytic copper layer, so that the metal layer 100 has good moisture resistance and a good printing effect, and it is convenient to prepare other film layers on the metal layer 100.

[0092] The thickness of the metal layer 100 can be selected to be 20-80 μm, and the volume resistivity of the metal layer 100 is ≤0.001 Ω·cm, thereby ensuring that the metal layer 100 has good conductive properties.

[0093] In this embodiment, the sum of the thicknesses of the metal layer 100, the first insulating layer and the third insulating layer 200 can be selected to be 100-180 μm, thereby ensuring that the metal layer 100, the first insulating layer and the third insulating layer 200 have good mechanical properties and durability, and reducing their production costs while meeting the requirements.

[0094] The heating layer 300 of this embodiment can be made of PTC material, that is, the heating layer includes a positive temperature coefficient heating layer. Therefore, the heating layer 300 can limit the flow of current when the temperature rises to a certain level, playing a protective role; and when the temperature drops below its specific temperature, the resistance will return to a lower level.

[0095] The positive temperature coefficient heating layer includes a polymer matrix and a conductive filler, wherein the polymer matrix includes polyethylene, polypropylene or polyvinyl chloride, and the conductive filler includes carbon black, graphite, copper powder, silver powder, tin oxide or zinc oxide.

[0096] Exemplarily, the metal layer 100 of this embodiment is electrically connected to the wire 500 through a conductive adhesive layer, thereby ensuring the conductivity between the metal layer 100 and the wire 500. A fourth insulating layer is also provided at the connection position between the metal layer 100 and the wire 500. It can be understood that the position of the metal layer 100 for connecting the wire can be located at the end of the metal layer 100; the fourth insulating layer covers the connection position between the metal layer 100 and the wire 500 to ensure the insulation of this position.

[0097] In this embodiment, the conductive adhesive layer includes a two-component epoxy resin conductive adhesive layer or a two-component acrylate conductive adhesive layer, the volume resistivity of the conductive adhesive layer is ≤0.001Ω·cm, and the contact resistance between the conductive adhesive layer and the metal layer 100 or the wire 500 is ≤0.05Ω, thereby ensuring good conductivity between the metal layer 100 and the wire 500.

[0098] The fourth insulating layer includes a polyurethane-modified acrylate layer or a silicone-modified acrylate layer, which has a low water vapor permeability while ensuring insulation, thereby preventing corrosion to the internal heating layer 300 .

[0099] Figure 3 A flow chart for preparing a heating film according to an embodiment of the present application.

[0100] Please refer to Figure 3 This embodiment also provides a method for preparing a heating film, comprising:

[0101] Step S110: providing a metal layer.

[0102] Exemplarily, the metal layer can be an aluminum foil layer, a rolled copper layer or an electrolytic copper layer, so that the metal layer has a good printing effect and is convenient for preparing other film layers on the metal layer. The thickness of the metal layer can be selected to be 20 to 80 μm, and the volume resistivity of the metal layer is ≤0.001Ω·cm, so as to ensure that the metal layer has good conductive properties.

[0103] Step S120 , preparing a first insulating layer on the first side of the metal layer.

[0104] Exemplarily, the first insulating layer may be a photocurable coating, which is formed on the first side of the metal layer by spraying or inkjet printing an insulating material and then curing it under light. The first insulating layer includes a polyurethane modified acrylate layer or a silicone modified acrylate layer.

[0105] Step S130: preparing a heat generating layer on the second side of the metal layer, wherein the heat generating layer is electrically connected to the metal layer; wherein the first side and the second side are opposite sides in the thickness direction of the metal layer.

[0106] Exemplarily, the preparation of the heat generating layer may be carried out according to the following steps:

[0107] First, the heat generating layer paste is printed on the second side of the metal layer.

[0108] Then, the printed heating layer slurry is baked and cured to form a heating layer.

[0109] The heating layer slurry is a slurry of PTC material, and the heating layer includes a positive temperature coefficient heating layer.

[0110] The positive temperature coefficient heating layer includes a polymer matrix and a conductive filler, the polymer matrix includes polyethylene, polypropylene or polyvinyl chloride, and the conductive filler includes carbon black, graphite, copper powder, silver powder, tin oxide or zinc oxide.

[0111] The baking temperature of the heating layer slurry can be 80-150° C.; the baking time of the heating layer slurry can be 15-30 minutes.

[0112] Step S140: prepare a second insulating layer on the side of the heating layer away from the metal layer.

[0113] Exemplarily, the second insulating layer can also be a photocurable coating, which is formed on the side of the heating layer away from the third insulating layer by spraying or inkjet printing the insulating material and curing it with light. The second insulating layer includes a polyurethane modified acrylate layer or a silicone modified acrylate layer.

[0114] Step S150: electrically connecting the wire to the metal layer.

[0115] Exemplarily, electrically connecting the wire to the metal layer may be performed according to the following steps:

[0116] First, a conductive adhesive layer is coated on the position of the metal layer for connecting the wire, and the wire is bonded to the conductive adhesive layer. It is understandable that the position of the metal layer for connecting the wire can be located at the end of the metal layer.

[0117] Then, a fourth insulating layer is coated on the bonding position between the metal layer and the wire. The fourth insulating layer can also be a photocurable coating. The fourth insulating layer is formed on the bonding position between the metal layer and the wire by spraying or inkjet printing the insulating material and then curing it with light.

[0118] The conductive adhesive layer includes a two-component epoxy resin conductive adhesive layer or a two-component acrylate conductive adhesive layer, the volume resistivity of the conductive adhesive layer is ≤0.001Ω·cm, and the contact resistance between the conductive adhesive layer and the metal layer or wire is ≤0.05Ω. The fourth insulating layer includes a polyurethane modified acrylate layer or a silicone modified acrylate layer.

[0119] The method of this embodiment further includes preparing a third insulating layer on the second side of the metal layer, the third insulating layer being located between the metal layer and the heating layer, wherein the third insulating layer is formed with a groove, the groove is connected to the metal layer to expose a portion of the metal layer, and the heating layer is electrically connected to the metal layer through the groove.

[0120] Exemplarily, the third insulating layer may also be a photocurable coating, and the third insulating layer may also be formed on the second side of the metal layer by spraying or inkjet printing an insulating material and then curing it under light. The third insulating layer includes a polyurethane modified acrylate layer or a silicone modified acrylate layer.

[0121] Specifically, the preparation of the third insulating layer can be carried out according to the following steps:

[0122] First, a shielding layer is covered on the second side of the metal layer, and the shielding layer can shield a part of the metal layer to prevent the insulating material from sticking to it.

[0123] Then, an insulating material is sprayed onto the metal layer covered with the shielding layer and cured by light, thereby forming an insulating layer on the second side of the metal layer.

[0124] Finally, the blocking layer is removed, and a groove connected to the metal layer is formed in the area shielded by the blocking layer, thereby forming a third insulating layer.

[0125] In this embodiment, the first insulating layer, the second insulating layer, the third insulating layer and the fourth insulating layer are all polyurethane-modified acrylate layers or silicone-modified acrylate layers, thereby ensuring that the heating film has a lower water vapor permeability and enhancing the heating film's ability to withstand high temperature and high humidity.

[0126] The metal layer can concentrate the heat and infrared radiation emitted by the heating layer to the second insulating layer, and at the same time play a role in heat distribution and heat preservation. The metal layer has good ductility. Compared with the current-carrying bar prepared by silver paste in the related art, the metal layer of this embodiment has better bending resistance. And since there is no need to prepare a special current-carrying bar, it is helpful to reduce the number of parts of the heating film and simplify the preparation process.

[0127] In this embodiment, the first insulating layer, the second insulating layer, the third insulating layer and the fourth insulating layer can be formed into a light-cured flexible coating by spraying insulating materials and then curing them under light. Compared with the solutions of related technologies, there is no need to heat and cure the adhesive layer to connect the adjacent film layers, which is more energy-efficient and efficient, and can avoid direct damage or hidden internal damage to the heating layer during heating and curing. At the same time, since there is no need to set the adhesive layer, the thermal resistance is also reduced and the heat transfer effect is improved.

[0128] In this embodiment, the metal layer and the wire are bonded by a conductive adhesive layer, which can not only maintain the reliability of the electrical connection between the two, but also form a conductive connection at room temperature. The preparation process does not require high-temperature curing, and the construction process is simple. It can also achieve electrical connection of different types of electrode materials, such as copper, aluminum and carbon fiber. The way of bonding the metal layer and the wire by a conductive adhesive layer is also convenient for subsequent maintenance.

[0129] This embodiment also provides a battery module, including the above-mentioned heating film.

[0130] It is understandable that, since the above-mentioned heating film is provided in the battery module, it is possible to ensure normal heating of the battery module while improving the high temperature and high humidity resistance of the heating film, thereby facilitating extending the performance and service life of the battery module.

[0131] This embodiment also provides a battery pack, including the above-mentioned battery module.

[0132] Specifically, one or more battery modules may be arranged in the battery pack as required. Since the battery pack adopts the above-mentioned battery module, it has better working stability, which is beneficial to improving its charging and discharging performance and extending the service life of the battery pack.

[0133] This embodiment also provides an electrical device, including the above-mentioned battery pack.

[0134] Specifically, the electrical equipment includes vehicles (such as new energy vehicles), aircraft, ships, computers, energy storage cabinets, etc. Since the electrical equipment adopts the above-mentioned battery pack, the electrical equipment has better working stability, which is beneficial to improving its charging and discharging performance and extending its service life.

[0135] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0136] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0137] It should be noted that in the description of this application, the terms "first" and "second" are only used to facilitate the description of different components, and cannot be understood as indicating or implying a sequential relationship, relative importance, or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0138] The various embodiments or implementation methods in the present application are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0139] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In the present application, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A heating film, characterized in that: The invention comprises a first insulating layer, a metal layer (100), a heating layer (300) and a second insulating layer (400), wherein the first insulating layer is formed on a first side of the metal layer (100), the heating layer (300) is formed on a second side of the metal layer (100), and the heating layer (300) is electrically connected to the metal layer (100); wherein the first side and the second side are opposite sides of the metal layer (100) in a thickness direction; the second insulating layer (400) is formed on a side of the heating layer (300) away from the metal layer (100), and the metal layer (100) is further connected to a wire (500); Wherein, the first insulating layer and the second insulating layer (400) are both photocurable coatings.

2. The heating film according to claim 1, characterized in that: The photocurable coating comprises a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

3. The heating film according to claim 1, characterized in that: The invention also comprises a third insulating layer (200), wherein the third insulating layer (200) is located between the metal layer (100) and the heating layer (300); the third insulating layer (200) is provided with a groove, wherein the groove is connected to the metal layer (100) to expose a part of the metal layer (100), and the heating layer (300) is electrically connected to the metal layer (100) through the groove.

4. The heating film according to claim 3, characterized in that: The third insulating layer (200) comprises a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

5. The heating film according to claim 3, characterized in that: The thickness of the first insulating layer, the second insulating layer (400) and the third insulating layer (200) are all 80-150 μm.

6. The heating film according to claim 3, characterized in that: The dielectric strength of the first insulating layer, the second insulating layer (400) and the third insulating layer (200) are all greater than or equal to 10 KV / mm.

7. The heating film according to claim 3, characterized in that: The surface resistivity of the first insulating layer, the second insulating layer (400) and the third insulating layer (200) are all greater than or equal to 1*10 12 Ω·cm.

8. The heating film according to claim 3, characterized in that: The water vapor transmission rates of the first insulating layer, the second insulating layer (400) and the third insulating layer (200) are all less than or equal to 1 g / m 2 / day.

9. The heating film according to claim 1, characterized in that: The metal layer (100) comprises an aluminum foil layer, a rolled copper layer or an electrolytic copper layer.

10. The heating film according to claim 8, characterized in that: The thickness of the metal layer (100) is 20 to 80 μm, and the volume resistivity of the metal layer (100) is ≤0.001 Ω·cm.

11. The heating film according to claim 1, characterized in that: The sum of the thicknesses of the metal layer (100), the first insulating layer and the third insulating layer (200) is 100 to 180 μm.

12. The heating film according to claim 1, characterized in that: The heating layer (300) comprises a positive temperature coefficient heating layer.

13. The heating film according to claim 12, characterized in that: The positive temperature coefficient heating layer comprises a polymer matrix and a conductive filler, wherein the polymer matrix comprises polyethylene, polypropylene or polyvinyl chloride, and the conductive filler comprises carbon black, graphite, copper powder, silver powder, tin oxide or zinc oxide.

14. The heating film according to claim 1, characterized in that: The metal layer (100) and the wire (500) are electrically connected via a conductive adhesive layer, and a fourth insulating layer is also provided at the connection position between the metal layer (100) and the wire (500).

15. The heating film according to claim 14, characterized in that: The conductive adhesive layer comprises a two-component epoxy resin conductive adhesive layer or a two-component acrylate conductive adhesive layer, the volume resistivity of the conductive adhesive layer is ≤0.001Ω·cm, and the contact resistance between the conductive adhesive layer and the metal layer (100) or the wire (500) is ≤0.05Ω.

16. The heating film according to claim 14, characterized in that: The fourth insulating layer includes a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

17. A method for preparing a heating film, characterized in that: include: providing a metal layer; Preparing a first insulating layer on a first side of the metal layer; A heat generating layer is prepared on the second side of the metal layer, and the heat generating layer is electrically connected to the metal layer; wherein the first side and the second side are opposite sides in the thickness direction of the metal layer; A second insulating layer is prepared on a side of the heat generating layer away from the metal layer; electrically connecting a wire to the metal layer; Wherein, the first insulating layer and the second insulating layer are both photocurable coatings.

18. The method for preparing a heating film according to claim 17, characterized in that: The photocurable coating comprises a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

19. The method for preparing a heating film according to claim 17, characterized in that: The first insulating layer is formed on the first side of the metal layer by spraying or inkjet printing an insulating material and then curing it under light; And / or, the second insulating layer is formed on the side of the heating layer away from the metal layer by spraying or inkjet printing an insulating material and then curing it under light.

20. The method for preparing a heating film according to claim 17, characterized in that: Also includes: A third insulating layer is prepared on the second side of the metal layer, and the third insulating layer is located between the metal layer and the heating layer; wherein the third insulating layer is formed with a groove, the groove is connected to the metal layer to expose part of the metal layer, and the heating layer is electrically connected to the metal layer through the groove.

21. The method for preparing a heating film according to claim 20, characterized in that: The third insulating layer includes a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

22. The method for preparing a heating film according to claim 20, characterized in that: The step of preparing a third insulating layer on the second side of the metal layer comprises: Covering the second side of the metal layer with a shielding layer; Spraying insulating material onto the metal layer covered with the shielding layer and curing it by light; The shielding layer is removed to form the third insulating layer.

23. The method for preparing a heating film according to claim 20, characterized in that: The step of preparing a heat generating layer on the second side of the metal layer comprises: Printing a heating layer paste on a side of the third insulating layer away from the metal layer; The printed heating layer slurry is baked and cured to form the heating layer.

24. The method for preparing a heating film according to claim 23, characterized in that: The heat generating layer includes a positive temperature coefficient heating layer.

25. The method for preparing a heating film according to claim 24, characterized in that: The positive temperature coefficient heating layer comprises a polymer matrix and a conductive filler, wherein the polymer matrix comprises polyethylene, polypropylene or polyvinyl chloride, and the conductive filler comprises carbon black, graphite, copper powder, silver powder, tin oxide or zinc oxide.

26. The method for preparing a heating film according to claim 23, characterized in that: The baking temperature of the heating layer slurry is 80-150° C.; the baking time of the heating layer slurry is 15-30 minutes.

27. The method for preparing a heating film according to claim 17, characterized in that: The electrically connecting the wire to the metal layer comprises: Coating a conductive adhesive layer at a position of the metal layer for connecting the wire, and bonding the wire to the conductive adhesive layer; A fourth insulating layer is coated on the bonding position between the metal layer and the wire.

28. The method for preparing a heating film according to claim 27, characterized in that: The conductive adhesive layer includes a two-component epoxy resin conductive adhesive layer or a two-component acrylate conductive adhesive layer, the volume resistivity of the conductive adhesive layer is ≤0.001Ω·cm, and the contact resistance between the conductive adhesive layer and the metal layer or the wire is ≤0.05Ω.

29. The method for preparing a heating film according to claim 27, characterized in that: The fourth insulating layer is a polyurethane-modified acrylate layer or a silicone-modified acrylate layer.

30. A battery module, characterized in that: Comprising the heating film as claimed in any one of claims 1-16.

31. A battery pack, characterized in that: Comprising at least one battery module as claimed in claim 30.

32. An electrical equipment, characterized in that: Comprising a battery pack as claimed in claim 31.

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