Battery pack and electric equipment

Abstract

The invention discloses a battery pack and electric equipment. The battery pack comprises a first battery cell, a second battery cell and an insulating layer, the first battery cell comprises a first electrode assembly; the second battery cell comprises a second electrode assembly, the first electrode assembly is connected with the second electrode assembly in series, the first battery cell and the second battery cell are stacked in the first direction, and the first direction is the thickness direction of the battery pack. The insulating layer has ductility and is located between the first electrode assembly and the second electrode assembly in the first direction, and the orthographic projection of the insulating layer overlaps the orthographic projection of the first electrode assembly and the orthographic projection of the second electrode assembly. The battery pack reduces the risk of fire or explosion when the battery pack is punctured by metal nails.

Description

Technical Field

[0001] This application belongs to the technical field of energy storage, and particularly relates to a battery pack and an electrical device. Background Art

[0002] As Figure 1 shown, the battery pack 100 generally includes a plurality of battery cells 10 to increase the overall capacity of the secondary battery, and the plurality of battery cells 10 are stacked in the thickness direction. For two battery cells 10 connected in series in the secondary battery, for the convenience of description, one of them is defined as the first battery cell 101, and the other is defined as the second battery cell 102. The negative terminal 13 of the first battery cell 101 is electrically connected to the positive terminal 14 of the second battery cell 102, so that the first battery cell 101 and the second battery cell 102 are connected in series. In the nail penetration test, the metal nail 200 pierces the housings and electrode plates of the first battery cell 101 and the second battery cell 102. The metal nail 200 makes electrical connection with the negative electrode plate 122 of the first battery cell 101 and also makes electrical connection with the negative electrode plate 122 of the second battery cell 102. The electrons provided by the negative electrode plate 122 of the second battery cell 102 reach the negative electrode plate 122 of the first battery cell 101 via the metal nail 200, and then pass through the negative terminal 13 of the first battery cell 101 and the positive terminal 14 of the second battery cell 102 in sequence to reach the positive electrode plate 121 of the second battery cell 102. The lithium ions provided by the negative electrode plate 122 of the second battery cell 102 pass through the separator 123 of the second battery cell 102 to reach the positive electrode plate 121 of the second battery cell 102, thus forming a short - circuit loop, which easily causes the battery cell 10 to catch fire or explode, and there are certain safety hazards. Summary of the Invention

[0003] In view of the above situation, it is necessary to provide a battery pack that can reduce the possibility of the battery cell catching fire or exploding when the battery pack is penetrated by a metal nail.

[0004] The first aspect of the embodiment of this application provides a battery pack, which includes a first battery cell, a second battery cell and an insulating layer. The first battery cell includes a first electrode assembly; the second battery cell includes a second electrode assembly. The first electrode assembly is connected in series with the second electrode assembly. The first battery cell and the second battery cell are stacked along a first direction, and the first direction is the thickness direction of the battery pack. Along the first direction, the insulating layer is located between the first electrode assembly and the second electrode assembly, and the orthographic projection of the insulating layer overlaps with the orthographic projections of both the first electrode assembly and the second electrode assembly.

[0005] In this battery pack, an insulating layer is provided between the first electrode assembly and the second electrode assembly. When a metal nail passes through the first battery cell and the second battery cell, the insulating layer can enter the interior of the electrode assembly under the drive of the metal nail, thereby being connected in series into the short - circuit loop, which is beneficial to reducing the short - circuit current, and thus reducing the risk of the battery pack catching fire or exploding.

[0006] In one or more embodiments of the present application, the first battery cell includes a first housing, and a first electrode assembly is received in the first housing; the second battery cell includes a second housing, and a second electrode assembly is received in the second housing; along a first direction, an insulating layer is located between the first housing and the second housing, and the insulating layer is located outside the first housing and the second housing. Arranging the insulating layer between the first housing and the second housing is beneficial to reducing the difficulty of arranging the insulating layer.

[0007] In one or more embodiments of the present application, the first battery cell includes a first housing, and a first electrode assembly is received in the first housing; the second battery cell includes a second housing, and a second electrode assembly is received in the second housing; the insulating layer is disposed inside at least one of the first housing and the second housing. In this way, the position of the insulating layer is constrained by at least one of the first housing and the second housing, which is beneficial to reducing the risk of the insulating layer falling off; and, compared with the solution where the insulating layer is disposed outside the battery cell, the distance between the insulating layer and the electrode assembly along the first direction is smaller, and the insulating layer can be connected in series with the electrode assembly and the metal nail by extending a shorter distance along the first direction, which is beneficial to increasing the probability of the insulating layer taking effect.

[0008] In one or more embodiments of the present application, along the first direction, the area of the overlapping part of the orthographic projection of the first electrode assembly and the orthographic projection of the insulating layer is S1, the area of the orthographic projection of the first electrode assembly is S2, and 0.3S2 ≤ S1 ≤ S2. Setting S1 ≥ 0.3S2 ensures that the area of the overlapping part of the orthographic projection of the first electrode assembly and the orthographic projection of the insulating layer is not too small, which is beneficial to increasing the possibility that the metal nail passes through the insulating layer when the battery pack is punctured by the metal nail, that is, increasing the possibility of the insulating layer taking effect.

[0009] In one or more embodiments of the present application, the first electrode assembly has a first surface facing the insulating layer along a first direction. The area of the first surface covered by the positive projection of the insulating layer along the first direction is the first region, and the remaining area is the second region. The second region is located in the middle of the first surface. When observed along the first direction, the first surface has a first side, a second side, a third side, and a fourth side. The first side and the second side are oppositely arranged along a second direction, and the third side and the fourth side are oppositely arranged along a third direction. The first direction, the second direction, and the third direction are perpendicular to each other in pairs. The second region has a first edge, a second edge, a third edge, and a fourth edge. The first side and the second side are oppositely arranged along the second direction, and the third side and the fourth side are oppositely arranged along the third direction. The first side and the first edge are on the same side of the first electrode assembly, the second side and the second edge are on the same side of the first electrode assembly, the third side and the third edge are on the same side of the first electrode assembly, and the fourth side and the fourth edge are on the same side of the electrode assembly. Along the second direction, the minimum distance from the first side to the second side is W1, the minimum distance from the first side to the first edge is D1, D1≥0.2W1, the minimum distance from the second side to the second edge is D2, D2≥0.2W1; along the third direction, the minimum distance from the third side to the fourth side is W2; the minimum distance from the third side to the third edge is D3, D3≥0.25W2, and the minimum distance from the fourth side to the fourth edge is D4, D4≥0.25W2. Compared with the middle part of the first electrode assembly, its edge position is more likely to be pierced during the use of the battery pack. Therefore, setting the insulating layer at the edge position of the first electrode assembly is beneficial to improving the safety of the battery pack.

[0010] In one or more embodiments of the present application, along the first direction, the thickness of the insulating layer is T1, and 0.1mm≤T1≤10mm. Setting T1≥0.1mm, the thickness of the insulating layer is not too small, which is beneficial to increasing the length of the insulating layer extending along the first direction driven by the metal nail, so as to reduce the risk that the insulating layer fails to be connected in series between the electrode assembly and the metal nail; setting T1≤10mm, the thickness of the insulating layer is not too large, which is beneficial to improving the energy density of the battery assembly.

[0011] In one or more embodiments of the present application, 0.5mm≤T1≤1mm. Setting T1≥0.5mm is beneficial to further increasing the length of the insulating layer extending along the first direction driven by the metal nail, so as to reduce the risk that the insulating layer fails to be connected in series between the electrode assembly and the metal nail; setting T1≤1mm is beneficial to further improving the energy density of the battery assembly.

[0012] In one or more embodiments of the present application, along the first direction, the thickness of the insulating layer is T1, and the thickness of the first battery cell is T2, where 0.05 ≤ T1 / T2 ≤ 1.5. Determining the thickness of the insulating layer according to the thickness of the first battery cell is conducive to adapting the thickness of the insulating layer to the thickness of the first battery cell; moreover, setting T1 / T2 ≥ 0.05 ensures that the thickness of the insulating layer is not too small, which is beneficial to increasing the length of the insulating layer extending along the first direction driven by the metal nail, thereby reducing the risk that the insulating layer fails to be connected in series between the electrode assembly and the metal nail; setting T1 / T2 ≤ 1.5 ensures that the thickness of the insulating layer is not too large, which is beneficial to improving the energy density of the battery assembly.

[0013] In one or more embodiments of the present application, the resistivity of the insulating layer is ρ, where 100 Ω·cm ≤ ρ ≤ 10 25 Ω·cm. Setting ρ ≥ 100 Ω·cm ensures that the resistivity of the insulating layer is not too small, which is beneficial to improving the effect of the insulating layer in reducing the short-circuit current. Setting ρ ≤ 10 25 Ω·cm ensures that the resistivity of the insulating layer is not too high, which is beneficial to reducing the difficulty of material selection for the insulating layer.

[0014] In one or more embodiments of the present application, 10 22 Ω·cm ≤ ρ ≤ 10 25 Ω·cm. Setting ρ ≥ 10 22 Ω·cm is beneficial to further improving the effect of the insulating layer in reducing the short-circuit current.

[0015] In one or more embodiments of the present application, the insulating layer is an insulating gel, and the materials of the insulating gel include at least one of polyethylene terephthalate, polybutylene terephthalate, polyarylate, etc., bisphenol A epoxy resin, bisphenol F epoxy resin, polyphenol glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, glycidyl ester epoxy resin, glycidylamine epoxy resin, polyisocyanate polyurethane, polyurethane resin, acrylic resin and its modified resin, polyalkyl silicone resin, polyaryl silicone resin, polyalkylaryl silicone resin, homogeneous polyesterimide resin, monoether polyesterimide resin, bisether anhydride polyesterimide resin, polyetherimide resin, polybismaleimide resin, norbornenedicarboxylic acid modified polyesterimide resin, polyamideimide resin, polybismaleimide, norbornene-capped polyimide resin, natural rubber or synthetic rubber. Compared with a solid insulating layer, the gel-state insulating layer has higher fluidity, which is beneficial to increasing the probability of generating the insulating layer.

[0016] In one or more embodiments of the present application, the insulating layer is double-sided adhesive paper, which includes a base material layer and adhesive layers provided on both sides of the base material layer. The adhesive layers are respectively adhered to the first electrode assembly and the second electrode assembly. The material of the base material layer includes at least one of polyethylene terephthalate, polyimide, polyethylene, polypropylene, polyvinyl chloride, kraft paper, cotton cloth, synthetic fiber cloth, metal foil, and glass fiber; the material of the adhesive layer includes at least one of rubber-based adhesives, silicone-based adhesives, hot melt adhesives, water-based adhesives, polyurethane-based adhesives, epoxy-based adhesives, and polyimide-based adhesives.

[0017] In one or more embodiments of the present application, the insulating layer is a separator film, which includes a separator film base material layer. The material of the separator film base material layer includes at least one of polyethylene, polypropylene, polyimide, polyamide, polysulfone, polyacrylonitrile, polyester, cellulose, polyether ether ketone, polyphenylene sulfide, polyacrylate, polyethylene terephthalate, polyparaphenylene terephthalamide, polyarylether sulfone ketone, aramid, or arsulfonamide.

[0018] In one or more embodiments of the present application, the separator film further includes a separator film adhesive layer provided on at least one surface of the separator film base material layer, and the side of the separator film adhesive layer away from the separator film base material layer faces the first electrode assembly and / or the second electrode assembly. The material of the separator film adhesive layer includes at least one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyimide, polyvinyl alcohol, sodium carboxymethyl cellulose, and acrylate.

[0019] The second aspect of the embodiments of the present application provides an electrical device, which includes the battery pack as described in any one of the foregoing embodiments. Description of the Drawings

[0020] Figure 1 is a schematic diagram of the short-circuit principle when the battery pack in the prior art is punctured by a metal nail.

[0021] Figure 2 is a schematic diagram of the structure of the battery pack in one embodiment of the present application.

[0022] Figure 3 is a schematic diagram of the structure of the battery cell in one embodiment of the present application.

[0023] Figure 4 is Figure 3 the schematic cross-sectional structure diagram at IV-IV.

[0024] Figure 5 is a schematic diagram of the structure of the battery pack in one embodiment of the present application when it is punctured by a metal nail.

[0025] Figure 6 is a schematic diagram of the structure of the battery pack in one embodiment of the present application.

[0026] Figure 7 It is a schematic structural diagram of a first electrode assembly in an embodiment of the present application.

[0027] Figure 8 It is a schematic structural diagram of an electrical device in an embodiment of the present application.

[0028] Description of main element symbols

[0029] 100. Battery pack; 10. Battery cell; 11. Housing; 12. Electrode assembly; 121. Positive electrode sheet; 1211. Positive current collector; 1212. Positive active material layer; 122. Negative electrode sheet; 1221. Negative current collector; 1222. Negative active material layer; 123. Separator; 13. Negative terminal; 14. Positive terminal; 101. First battery cell; 1011. First housing; 1012. First electrode assembly; 10121. First surface; 10121a. First region; 10121b. Second region; 1013. First side; 1014. Second side; 1015. Third side; 1016. Fourth side; 1017. First edge; 1018. Second edge; 1019. Third edge; 1020. Fourth edge; 102. Second battery cell; 1021. Second housing; 1022. Second electrode assembly; 20. Insulating layer; 1000. Electrical device; 200. Metal nail; X. First direction; Y. Second direction; Z. Third direction.

[0030] The following specific embodiments will further illustrate the present application in conjunction with the above-mentioned drawings. Specific embodiments

[0031] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0032] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element. When an element is considered to be "disposed" on another element, it can be directly disposed on the other element or there may be an intermediate element.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0034] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is more than two, unless otherwise specifically defined.

[0035] In the description of the embodiments of the present application, the term "vertical" is used to describe the ideal state between two components. In the actual production or use state, there may be a state approximately vertical between two components. The two components described as "vertical" may not be absolute straight lines or planes, and may also be approximately straight lines or planes. From a macroscopic perspective, as long as the overall extension direction is a straight line or a plane, the components can be considered as "straight lines" or "planes".

[0036] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments may be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Without conflict, the various embodiments in the present application can be combined with each other.

[0037] A first aspect of an embodiment of the present application provides a battery pack, which includes a first battery cell, a second battery cell and an insulating layer. The first battery cell includes a first electrode assembly; the second battery cell includes a second electrode assembly. The first electrode assembly is connected in series with the second electrode assembly. The first battery cell and the second battery cell are stacked along a first direction, and the first direction is the thickness direction of the battery pack. The insulating layer has ductility. Along the first direction, the insulating layer is located between the first electrode assembly and the second electrode assembly, and the orthographic projection of the insulating layer overlaps with the orthographic projections of both the first electrode assembly and the second electrode assembly.

[0038] In this battery pack, an insulating layer is provided between the first electrode assembly and the second electrode assembly. When a metal nail penetrates through the first battery cell and the second battery cell, the insulating layer can be driven by the metal nail to enter the interior of the electrode assembly, thereby being connected in series into the short-circuit loop, which is beneficial to reducing the short-circuit current and thus reducing the risk of the battery pack catching fire or exploding.

[0039] The following further describes the embodiments of the present application with reference to the accompanying drawings.

[0040] As Figure 2 shown, an embodiment of the present application provides a battery pack 100, which includes a plurality of battery cells 10. The plurality of battery cells 10 are stacked along a first direction X, and the first direction X is the thickness direction of the battery pack 100 and also the thickness direction of a single battery cell 10.

[0041] In some embodiments, all the battery cells 10 are connected in series with each other.

[0042] In some embodiments, a part of the plurality of battery cells 10 are connected in series, and a part of the battery cells 10 are connected in parallel.

[0043] In some embodiments, as Figure 3 and Figure 4 shown, the battery cell 10 includes a housing 11, an electrode assembly 12, a negative terminal 13, and a positive terminal 14. The electrode assembly 12 is received in the housing 11. The electrode assembly 12 is configured to store and release electrical energy. The negative terminal 13 is connected to the electrode assembly 12 and extends out of the housing 11. The positive terminal 14 is connected to the electrode assembly 12 and extends out of the housing 11. The positive terminal 14 and the negative terminal 13 are configured to connect the battery cell 10 to an external circuit.

[0044] In some embodiments, the housing 11 is a rigid housing 11, such as a steel shell; in other embodiments, the housing 11 is a packaging bag.

[0045] In some embodiments, as Figure 4 shown, the electrode assembly 12 includes a positive electrode plate 121, a negative electrode plate 122, and a separator 123. The positive electrode plate 121, the separator 123, and the negative electrode plate 122 are stacked in sequence. The positive terminal 14 is connected to the positive electrode plate 121, and the negative terminal 13 is connected to the negative electrode plate 122.

[0046] In some embodiments, as Figure 4 shown, the positive electrode plate 121 includes a positive current collector 1211 and a positive active material layer 1212. The positive active material layer 1212 is provided on at least one surface of the positive current collector 1211 along its thickness direction.

[0047] In some embodiments, the positive current collector 1211 is a metal layer. By way of example, the positive current collector 1211 may be a metal layer including at least one of aluminum, nickel, tantalum, and titanium, such as an aluminum foil.

[0048] In some embodiments, the positive active material layer 1212 includes a positive active material, and the positive active material includes at least one of lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium iron phosphate, lithium manganese iron phosphate, or lithium manganate.

[0049] In some embodiments, as Figure 4 shown, the negative electrode plate 122 includes a negative current collector 1221 and a negative active material layer 1222. The negative active material layer 1222 is provided on at least one surface of the negative current collector 1221 along its thickness direction.

[0050] In some embodiments, the negative current collector 1221 is a metal layer. By way of example, the negative current collector 1221 may be a metal layer including at least one of copper, nickel, tantalum, and titanium, such as a copper foil.

[0051] In some embodiments, as Figure 4 shown, the negative electrode active material layer 1222 includes a negative electrode active material, and the negative electrode active material includes at least one of graphite, hard carbon, soft carbon, silicon, silicon oxide material, and silicon carbon material.

[0052] In some embodiments, as Figure 4 shown, the positive electrode sheet 121, the separator 123, and the negative electrode sheet 122 are stacked and wound to form a wound structure.

[0053] In some embodiments, a plurality of positive electrode sheets 121, multiple layers of separator 123, and a plurality of negative electrode sheets 122 are stacked to form a stacked structure. For any adjacent positive electrode sheet 121 and a negative electrode sheet 122, the separator 123 is disposed therebetween at intervals.

[0054] In some embodiments, the separator 123 is a film material capable of insulating, such as a polyethylene film, a polypropylene film, a polyester film, or a polyimide film.

[0055] In some embodiments, the battery cell 10 further includes an electrolyte (not shown in the figure), and the electrolyte is housed in the housing 11.

[0056] In some embodiments, the electrolyte includes an electrolyte salt. The electrolyte salt includes at least one of an organic lithium salt or an inorganic lithium salt.

[0057] In some embodiments, the electrolyte salt includes, but is not limited to, at least one of lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl)imide LiN(CF3SO2)2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO2F)2) (LiFSI), lithium hexafluorocaesium (LiCsF6), lithium perchlorate (LiClO4), or lithium trifluoromethanesulfonate (LiCF3SO3).

[0058] In some embodiments, as Figure 2As shown, two of the multiple battery cells 10 are connected in series with each other. For ease of distinction, one is the first battery cell 101 and the other is the second battery cell 102. The housing 11 of the first battery cell 101 is the first housing 1011, and the electrode assembly 12 of the first battery cell 101 is the first electrode assembly 1012; the housing 11 of the second battery cell 102 is the second housing 1021, and the electrode assembly 12 of the second battery cell 102 is the second electrode assembly 1022. The first battery cell 101 is connected in series with the second battery cell 102, and the first electrode assembly 1012 is connected in series with the second electrode assembly 1022. The battery pack 100 further includes an insulating layer 20. The insulating layer 20 has ductility. Along the first direction X, the insulating layer 20 is located between the first electrode assembly 1012 and the second electrode assembly 1022, and the orthographic projection of the insulating layer 20 overlaps with the orthographic projections of both the first electrode assembly 1012 and the second electrode assembly 1022. Herein, the fact that the insulating layer 20 has ductility means that during a nail penetration test, when the metal nail 200 penetrates the battery pack 100, the material of the insulating layer 20 can be extended and enter the interior of the electrode assembly 12 under the drive of the metal nail 200, thereby blocking the electrical connection between the electrode assembly 12 and the metal nail 200.

[0059] In this battery pack 100, as Figure 5 shown, an insulating layer 20 is provided between the first electrode assembly 1012 and the second electrode assembly 1022. When the metal nail 200 penetrates the first battery cell 101 and the second battery cell 102, the insulating layer 20 can enter the interior of the electrode assembly 12 under the drive of the metal nail 200, thereby being connected in series into the short - circuit loop, which is beneficial to reducing the short - circuit current and thus reducing the risk of fire or explosion of the battery pack 100.

[0060] In some embodiments, as Figure 2 shown, along the first direction X, the insulating layer 20 is located between the first housing 1011 and the second housing 1021, and the insulating layer 20 is located outside the first housing 1011 and the second housing 1021. Arranging the insulating layer 20 between the first housing 1011 and the second housing 1021 is beneficial to reducing the difficulty of arranging the insulating layer 20.

[0061] In some embodiments, as Figure 6 shown, the insulating layer 20 is provided inside at least one of the first housing 1011 and the second housing 1021. In this way, restricting the position of the insulating layer 20 by at least one of the first housing 1011 and the second housing 1021 is beneficial to reducing the risk of the insulating layer 20 falling off; and, compared with the scheme of arranging the insulating layer 20 outside the battery cell 10, the distance between the insulating layer 20 and the electrode assembly 12 along the first direction X is smaller, and the insulating layer 20 can be connected in series with the electrode assembly 12 and the metal nail 200 by extending a shorter distance along the first direction X, which is beneficial to increasing the probability of the insulating layer 20 taking effect.

[0062] In some embodiments, along the first direction X, the area of the overlapping part of the orthographic projection of the first electrode assembly 1012 and the orthographic projection of the insulating layer 20 is S1, and the area of the orthographic projection of the first electrode assembly 1012 is S2, where 0.3S2 ≤ S1 ≤ S2. By setting S1 ≥ 0.3S2, the area of the overlapping part of the orthographic projection of the first electrode assembly 1012 and the orthographic projection of the insulating layer 20 is not too small, which is beneficial to increasing the possibility that the metal nail 200 passes through the insulating layer 20 when the battery pack 100 is punctured by the metal nail 200, that is, increasing the possibility that the insulating layer 20 plays a role.

[0063] In some embodiments, as Figure 2 shown, along the first direction X, the thickness of the insulating layer 20 is T1, where 0.1 mm ≤ T1 ≤ 10 mm. By setting T1 ≥ 0.1 mm, the thickness of the insulating layer 20 is not too small, which is beneficial to increasing the length that the insulating layer 20 extends along the first direction X driven by the metal nail 200, so as to reduce the risk that the insulating layer 20 fails to be connected in series between the electrode assembly 12 and the metal nail 200; by setting T1 ≤ 10 mm, the thickness of the insulating layer 20 is not too large, which is beneficial to increasing the energy density of the battery pack 100.

[0064] In some embodiments, 0.5 mm ≤ T1 ≤ 1 mm. By setting T1 ≥ 0.5 mm, it is beneficial to further increase the length that the insulating layer 20 extends along the first direction X driven by the metal nail 200, so as to reduce the risk that the insulating layer 20 fails to be connected in series between the electrode assembly 12 and the metal nail 200; by setting T1 ≤ 1 mm, it is beneficial to further increase the energy density of the battery pack 100.

[0065] In some embodiments, along the first direction X, the thickness of the insulating layer 20 is T1, and the thickness of the first battery cell 101 is T2, where 0.05 ≤ T1 / T2 ≤ 1.5. Determining the thickness of the insulating layer 20 according to the thickness of the first battery cell 101 is beneficial to making the thickness of the insulating layer 20 adapt to the thickness of the first battery cell 101; moreover, by setting T1 / T2 ≥ 0.05, the thickness of the insulating layer 20 is not too small, which is beneficial to increasing the length that the insulating layer 20 extends along the first direction X driven by the metal nail 200, so as to reduce the risk that the insulating layer 20 fails to be connected in series between the electrode assembly 12 and the metal nail 200; by setting T1 / T2 ≤ 1.5, the thickness of the insulating layer 20 is not too large, which is beneficial to increasing the energy density of the battery pack 100.

[0066] In some embodiments, the resistivity of the insulating layer 20 is ρ, where 100 Ω·cm ≤ ρ ≤ 10 25 Ω·cm. By setting ρ ≥ 100 Ω·cm, the resistivity of the insulating layer 20 is not too small, which is beneficial to improving the effect of the insulating layer 20 in reducing the short-circuit current. By setting ρ ≤ 10 25Ω·cm, the resistivity of the insulating layer 20 is not too high, which is beneficial to reducing the material selection difficulty of the insulating layer 20.

[0067] In some embodiments, 10 22 Ω·cm ≤ ρ ≤ 10 25 Ω·cm. Setting ρ ≥ 10 22 Ω·cm is beneficial to further improving the effect of the insulating layer 20 in reducing the short-circuit current.

[0068] In some embodiments, the insulating layer 20 is an insulating gel, and the materials of the insulating gel include at least one of polyethylene terephthalate, polybutylene terephthalate, polyarylate, etc., bisphenol A epoxy resin, bisphenol F epoxy resin, polyphenol glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, glycidyl ester epoxy resin, glycidylamine epoxy resin, polyisocyanate polyurethane, polyurethane resin, acrylic resin and its modified resin, polyalkyl silicone resin, polyaryl silicone resin, polyalkylaryl silicone resin, homogeneous polyesterimide resin, monoether polyesterimide resin, bisether anhydride polyesterimide resin, polyetherimide resin, polybismaleimide resin, norbornenedicarboxylic acid modified polyesterimide resin, polyamideimide resin, polybismaleimide, norbornene-terminated polyimide resin, natural rubber or synthetic rubber. Compared with the solid insulating layer 20, the gel-state insulating layer 20 has higher fluidity, which is beneficial to increasing the possibility of the generation probability of the insulating layer 20.

[0069] In some embodiments, the insulating layer is double-sided adhesive paper, and the double-sided adhesive paper includes a base material layer and adhesive layers provided on both sides of the base material layer. The adhesive layers respectively bond the first electrode assembly and the second electrode assembly. The materials of the base material layer include at least one of polyethylene terephthalate, polyimide, polyethylene, polypropylene, polyvinyl chloride, kraft paper, cotton cloth, synthetic fiber cloth, metal foil, and glass fiber; the materials of the adhesive layer include at least one of rubber-based adhesives, silicone-based adhesives, hot melt adhesives, water-based adhesives, polyurethane-based adhesives, epoxy-based adhesives, and polyimide-based adhesives.

[0070] In some embodiments, the insulating layer is a separator film, and the separator film includes a separator film base material layer. The materials of the separator film base material layer include at least one of polyethylene, polypropylene, polyimide, polyamide, polysulfone, polyacrylonitrile, polyester, cellulose, polyether ether ketone, polyphenylene sulfide, polyacrylate, polyethylene terephthalate, polybenzamide, polyarylether sulfone ketone, aramid, or arsulfonamide.

[0071] In one or more embodiments of the present application, the separator further includes a separator adhesive layer disposed on at least one surface of the separator substrate layer, and the side of the separator adhesive layer away from the separator substrate layer faces the first electrode assembly and / or the second electrode assembly. The material of the separator adhesive layer includes at least one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyimide, polyvinyl alcohol, sodium carboxymethyl cellulose, and acrylate.

[0072] In some embodiments, as Figure 7 shown, the first electrode assembly 1012 has a first surface 10121, the first surface 10121 faces the insulating layer 20 along the first direction X, the region of the first surface 10121 covered by the positive projection of the insulating layer 20 along the first direction X is the first region 10121a, and the remaining region is the second region 10121b. The second region 10121b is located in the middle of the first surface 10121. Specifically, when observed along the first direction X, the first surface 10121 has a first side 1013, a second side 1014, a third side 1015, and a fourth side 1016. The first side 1013 and the second side 1014 are oppositely arranged along the second direction Y, the third side 1015 and the fourth side 1016 are oppositely arranged along the third direction Z, and the first direction X, the second direction Y, and the third direction Z are perpendicular to each other in pairs. The second region 10121b has a first edge 1017, a second edge 1018, a third edge 1019, and a fourth edge 1020. The first side 1013 and the second side 1014 are oppositely arranged along the second direction Y, the third side 1015 and the fourth side 1016 are oppositely arranged along the third direction Z. The first side 1013 and the first edge 1017 are on the same side of the first electrode assembly 1012, the second side 1014 and the second edge 1018 are on the same side of the first electrode assembly 1012, the third side 1015 and the third edge 1019 are on the same side of the first electrode assembly 1012, and the fourth side 1016 and the fourth edge 1020 are on the same side of the electrode assembly 12. Along the second direction Y, the minimum distance from the first side 1013 to the second side 1014 is W1, the minimum distance from the first side 1013 to the first edge 1017 is D1, D1≥0.2W1, the minimum distance from the second side 1014 to the second edge 1018 is D2, D2≥0.2W1. Along the third direction Z, the minimum distance from the third side 1015 to the fourth side 1016 is W2; the minimum distance from the third side 1015 to the third edge 1019 is D3, D3≥0.25W2, and the minimum distance from the fourth side 1016 to the fourth edge 1020 is D4, D4≥0.25W2. Compared with the middle part of the first electrode assembly 1012 (corresponding to the second region 10121b), its edge position (corresponding to the first region 10121a) is more likely to be punctured during the use of the battery pack 100. Therefore, disposing the insulating layer 20 at the edge position of the first electrode assembly 1012 is beneficial to improving the safety of the battery pack 100.

[0073] As Figure 8 shown, an embodiment of the present application further provides an electrical device 1000, which includes a battery pack 100 involved in any of the foregoing embodiments.

[0074] In some embodiments, the electrical device 1000 includes, but is not limited to, mobile phones, laptop computers, power tools, and electric toys.

[0075] To verify the effects of the solutions in the embodiments of the present application, the inventors conducted the following experiments. The experimental work included 24 experimental groups, one of which was a comparative group, and the remaining 23 were embodiments. Each experimental group included 50 secondary batteries.

[0076] The preparation process of the battery pack 100 in Embodiment 1 includes the following steps:

[0077] (1) Preparation of the positive electrode sheet 121: Mix the active material lithium cobalt oxide (LiCoO2), conductive carbon black (Super P), CNT (carbon nanotube), and polyvinylidene fluoride (PVDF) in a weight ratio of 97.5:0.5:0.5:1.5, add N-methylpyrrolidone (NMP) as a solvent, and formulate a positive electrode active material with a solid content of 75 wt%, and stir evenly for standby. Use an aluminum foil with a thickness of 10 μm as the positive electrode current collector 1211. Use a slot coater to evenly coat the above-mentioned active material on one surface of the positive electrode current collector 1211 along its thickness direction, and then dry it at 90 °C to obtain a positive electrode sheet 121 with a single-sided coating of the positive electrode active material. Then repeat the above coating steps on the other surface of the positive electrode current collector 1211 along its thickness direction to obtain a positive electrode sheet 121 with both sides coated with the positive electrode active material layer 1212. At this time, the thickness of each positive electrode active material layer 1212 is 90 μm. Then cold press the coated positive electrode sheet 121. After cold pressing, the thickness of the positive electrode active material layer 1212 is 80 μm. Then weld the positive terminal 14 to the part of the positive electrode current collector 1211 not covered by the positive electrode active material layer 1212.

[0078] (2) Preparation of the negative electrode sheet 122: Mix artificial graphite as the active material, conductive carbon black (Super P), styrene-butadiene rubber (SBR), and CMC (sodium carboxymethyl cellulose) in a weight ratio of 97:0.5:1.3:1.2, add deionized water as a solvent, and formulate a negative electrode active material with a weight percentage of 50 wt%. Stir evenly and set aside. Use a copper foil with a thickness of 10 μm as the negative electrode current collector 1221. Use a slot coater to evenly coat the above-mentioned negative electrode active material on one surface of the negative electrode current collector 1221 along its thickness direction, and then dry it at 110 °C to obtain a negative electrode sheet 122 with a single-sided coated negative electrode active material layer 1222. Then repeat the above steps on the other surface of the negative electrode current collector 1221 along its thickness direction to obtain a negative electrode sheet 122 with both sides coated with the negative electrode active material layer 1222. At this time, the thickness of each negative electrode active material layer 1222 is 90 μm. Then cold press the coated negative electrode sheet 122, and the thickness of the negative electrode active material layer 1222 after cold pressing is 80 μm. After that, weld the negative terminal 13 to the part of the negative electrode current collector 1221 that is not covered by the negative electrode active material layer 1222.

[0079] (3) Preparation of the electrolyte: In a dry argon atmosphere, first mix ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a mass ratio of EC:EMC:DEC = 30:50:20 to form a basic organic solvent, and then add lithium hexafluorophosphate (LiPF6) as a lithium salt to the basic organic solvent, dissolve and mix evenly to obtain an electrolyte with a lithium salt concentration of 1.15 mol / L.

[0080] (4) Preparation of the separator: Use a 7-μm-thick polyethylene porous polymer film as the separator 123.

[0081] (5) Preparation of the electrode assembly 12: Stack and wind the positive electrode sheet 121, the separator 123, and the negative electrode sheet 122 to obtain the electrode assembly 12.

[0082] (6) Assembly of the battery cell 10: Place the aluminum plastic film formed with a pit into the assembly fixture with the pit surface facing up, place the electrode assembly 12 into the pit, and apply an external force to press it tightly. Then cover another aluminum plastic film formed with a pit with the pit surface facing down on the electrode assembly 12, and thermally seal three edges of the two aluminum plastic films by thermal pressing. The un-thermally sealed edge is the side where the negative terminal 13 and the positive terminal 14 extend out of the housing 11, and this edge forms a top seal after thermal sealing. After that, inject the electrolyte through the un-thermally sealed edge, and through processes such as vacuum packaging, standing, thermal pressing formation, and shaping, the battery cell 10 is obtained.

[0083] (7) Assembly of the battery pack 100: Take a circuit board and two battery cells 10 manufactured by the foregoing steps. Electrically connect the negative terminal 13 of one battery cell 10 to the circuit board, and electrically connect the positive terminal 14 of the other battery cell 10 to the circuit board, so that the two battery cells 10 are connected in series. Coat an insulating layer 20 between the two battery cells 10. Among them, the polyalkyl silicone resin material used in the material of the insulating layer 20 is polydimethylsiloxane; the bisether anhydride type polyesterimide resin material used is sulfonated bisether anhydride polyesterimide; the polyaryl silicone resin material used is polyphenylsiloxane; the polyphenol type glycidyl ether epoxy resin material used is tetraphenylethane type epoxy resin; the monoether type polyesterimide resin material used is mono-phenyl ether tetracarboxylic dianhydride (MEPA) based resin; the polyalkylaryl silicone resin material used is methylphenyl silicone resin.

[0084] The preparation method of the battery pack 100 in the comparative example is basically the same as that in Example 1, and the difference is that the secondary battery in the comparative example does not have the insulating layer 20.

[0085] The preparation process of the battery pack 100 in Examples 2 to 10 is basically the same as that in Example 1, and the difference is that some parameters of the battery pack 100 in Examples 2 to 10 are different from those in Example 1. The specific differences can be seen in Table 1.

[0086] The preparation process of the battery pack 100 in Examples 11 to 14 is basically the same as that in Example 1, and the difference is that the material of the insulating layer 20 used in the battery pack 100 in Examples 11 to 14 is different from that in Example 1. The specific differences can be seen in Table 1.

[0087] After the battery pack 100 is prepared according to the foregoing steps, the volume energy density of the battery packs 100 in Examples 1 to 10 is tested. The specific process of the test is as follows:

[0088] 1) Maintain the test temperature at 25 °C;

[0089] 2) Let the battery pack 100 stand for 30 min;

[0090] 3) Constant current charge at 5C to 4.25V, and then constant voltage charge to 3C;

[0091] 4) Constant current charge at 3C to 4.35V, and then constant voltage charge to 1.5C;

[0092] 5) Constant current charge at 1.5C to 4.45V, and then constant voltage charge to 0.05C;

[0093] 6) Stand for 5 min;

[0094] 7) Constant current discharge at 0.7C to 3V, and record the discharge capacity;

[0095] 8) Let it stand for 5 min;

[0096] 9) Calculate the volume energy density. The volume energy density = discharge energy / (length of battery pack 100 × width of secondary battery × thickness). The volume energy density of battery packs 100 in the same group is averaged.

[0097] Perform nail penetration tests on battery packs 100 in all experimental groups. The specific process of the test is as follows:

[0098] Place battery pack 100 in a normal temperature environment. Charge battery pack 100 at a constant current of 0.5C until the voltage reaches 4.2V, and then charge it at a constant voltage until the current reaches 0.025C. Transfer battery pack 100 to the nail penetration test equipment. Keep the test environment temperature at 25°C. Pierce battery pack 100 with a steel nail. The diameter of the steel nail is 3mm, the length of the steel nail tip is 16 ± 0.5mm, the total length of the steel nail is 100 ± 0.5mm, and the steel nail passes through battery pack 100 at a uniform speed of 150mm / s and stays for 60 min. If battery pack 100 does not catch fire or explode, it is considered to pass. Subsequently, calculate the passing rate of the nail penetration test. The passing rate = the number of battery packs 100 that did not catch fire or explode / 50.

[0099] The differences in parameters between Example 2 to Example 23 and those in Example 1 are listed in Table 1. Except for the differences listed in Table 1, other parameters are the same as those in Example 1. In each of the examples, D1 = D2 and D3 = D4.

[0100] In Example 21, a double-sided adhesive tape is pasted between the first electrode assembly and the second electrode assembly to obtain a battery pack. The material of the base layer in the double-sided adhesive tape used is polyethylene, and the material of the adhesive layer is polydimethylsiloxane.

[0101] In Example 22, the material of the base layer of the separator used is polyethylene.

[0102] In Example 23, the material of the base layer of the separator used is polyethylene, and the binder in the adhesive layer of the separator is polyvinylidene fluoride.

[0103] The experimental results are recorded in Table 1.

[0104] Table 1

[0105]

[0106]

[0107]

[0108]

[0109]

[0110] Note: In Table 1, " / " indicates no such data.

[0111] As can be seen from Table 1, compared with Comparative Example 1, the battery packs 100 in Examples 1 to 14 have a higher passing rate in the nail penetration test. It can be seen that by providing an insulating layer 20 between the first electrode assembly 12 and the second electrode assembly 12, when the metal nail 200 penetrates through the first battery cell 101 and the second battery cell 102, the insulating layer 20 can enter the interior of the electrode assembly 12 under the drive of the metal nail 200, and thus be connected in series to the short-circuit loop, which is beneficial to reducing the short-circuit current, and thereby reducing the risk of the battery pack 100 catching fire or exploding.

[0112] In Examples 2 to 5, the battery pack 100 satisfies 0.1 mm ≤ T1 ≤ 10 mm. Compared with Example 1, the battery packs 100 in Examples 2 to 5 have a higher passing rate in the nail penetration test. It can be seen that by setting T1 ≥ 0.1 mm, the thickness of the insulating layer 20 is not too small, which is beneficial to increasing the length of the insulating layer 20 extending along the first direction X under the drive of the metal nail 200, so as to reduce the risk that the insulating layer 20 fails to be connected in series between the electrode assembly 12 and the metal nail 200; compared with Example 6, the average volume energy density of the battery packs 100 in Examples 2 to 5 is higher. It can be seen that by setting T1 ≤ 10 mm, the thickness of the insulating layer 20 is not too large, which is beneficial to increasing the energy density of the battery pack 100.

[0113] In Examples 3 and 4, the battery pack 100 satisfies 0.5 mm ≤ T1 ≤ 1 mm. Compared with Example 2, the battery packs 100 in Examples 3 and 4 have a higher passing rate in the nail penetration test. It can be seen that by setting T1 ≥ 0.5 mm, it is beneficial to further increase the length of the insulating layer 20 extending along the first direction X under the drive of the metal nail 200, so as to reduce the risk that the insulating layer 20 fails to be connected in series between the electrode assembly 12 and the metal nail 200; compared with Example 5, the average volume energy density of the battery packs 100 in Examples 3 and 4 is higher. It can be seen that by setting T1 ≤ 1 mm, it is beneficial to further increase the energy density of the battery pack 100.

[0114] In Embodiment 8 and Embodiment 9, the battery pack 100 satisfies 0.05 ≤ T1 / T2 ≤ 1.5. Compared with Embodiment 7, the passing rate of the battery pack 100 in the nail penetration test in Embodiment 8 and Embodiment 9 is higher. It can be seen that by setting T1 / T2 ≥ 0.05, the thickness of the insulating layer 20 is not too small, which is beneficial to increasing the length of the insulating layer 20 extending along the first direction X driven by the metal nail 200, so as to reduce the risk that the insulating layer 20 fails to be connected in series between the electrode assembly 12 and the metal nail 200. Compared with Embodiment 10, the average volume energy density of the battery pack 100 in Embodiment 8 and Embodiment 9 is higher. It can be seen that by setting T1 / T2 ≤ 1.5, the thickness of the insulating layer 20 is not too large, which is beneficial to increasing the energy density of the battery pack 100.

[0115] In Embodiments 12 to 14, the battery pack 100 satisfies 100 Ω·cm ≤ ρ ≤ 10 25 Ω·cm. Compared with Embodiment 11, the passing rate of the battery pack 100 in the nail penetration test in Embodiments 12 to 14 is higher. It can be seen that by setting ρ ≥ 100 Ω·cm, the resistivity of the insulating layer 20 is not too small, which is beneficial to enhancing the effect of the insulating layer 20 in reducing the short-circuit current. On this basis, by setting ρ ≤ 10 25 Ω·cm, it is beneficial to reducing the material selection difficulty of the insulating layer 20.

[0116] In Embodiments 13 and 14, the battery pack 100 satisfies 10 22 Ω·cm ≤ ρ ≤ 10 25 Ω·cm. Compared with Embodiment 12, the passing rate of the battery pack 100 in the nail penetration test in Embodiments 13 and 14 is higher. It can be seen that by setting ρ ≥ 10 22 Ω·cm, it is beneficial to further enhancing the effect of the insulating layer 20 in reducing the short-circuit current.

[0117] In Embodiments 3, 15 to 17, when D1 / W1 < 0.2, the passing rate of the nail penetration test is relatively low; when D1 / W1 ≥ 0.2 and as D1 / W1 increases, the passing rate of the nail penetration test increases. This is because the area ratio of the insulating layer 20 increases, which is beneficial to enhancing the effect of the insulating layer 20 in reducing the short-circuit current, thereby reducing the possibility of the battery pack 100 catching fire or exploding.

[0118] In Embodiments 3, 18 to 20, when D3 / W2 < 0.25, the passing rate of the nail penetration test is relatively low; when D3 / W2 ≥ 0.25 and as D3 / W2 increases, the passing rate of the nail penetration test increases. This is because the area ratio of the insulating layer 20 increases, which is beneficial to enhancing the effect of the insulating layer 20 in reducing the short-circuit current, thereby reducing the possibility of the battery pack 100 catching fire or exploding.

[0119] In Example 21, the insulating layer material is replaced with double-sided adhesive paper, which can also improve the passing rate of the nail penetration test of the battery pack 100 compared with the comparative example.

[0120] In Examples 22 and 23, the insulating layer is replaced with a separator substrate layer or a separator substrate layer plus a separator adhesive layer. Compared with the comparative example, the passing rate of the nail penetration test of the battery pack 100 in Examples 22 and 23 is also improved. Additionally, it can be seen that the insulating layer with a separator adhesive layer in Example 23 has a more obvious improvement in the passing rate of the nail penetration test of the battery pack 100 compared to the insulating layer with only a separator substrate layer.

[0121] Those of ordinary skill in the art of this technology should recognize that the above embodiments are only used to illustrate the present application, rather than to limit the present application. As long as within the scope of the substantial spirit of the present application, appropriate changes and variations made to the above embodiments fall within the scope of the disclosure of the present application.

Claims

1. A battery pack, characterized in that: include: A first battery cell, the first battery cell comprising a first electrode assembly; a second battery cell, the second battery cell comprising a second electrode assembly, the first electrode assembly being connected in series with the second electrode assembly, the first battery cell and the second battery cell being stacked along a first direction, the first direction being a thickness direction of the battery pack; An insulating layer, along the first direction, the insulating layer is located between the first electrode assembly and the second electrode assembly, and the orthographic projection of the insulating layer overlaps with the orthographic projections of the first electrode assembly and the second electrode assembly.

2. The battery pack according to claim 1, wherein: The first battery cell includes a first shell, and the first electrode assembly is accommodated in the first shell; The second battery cell includes a second shell, and the second electrode assembly is accommodated in the second shell; The battery assembly meets one of the following conditions: a. Along the first direction, the insulating layer is located between the first shell and the second shell, and the insulating layer is located outside the first shell and the second shell; b. The insulating layer is disposed inside at least one of the first shell and the second shell.

3. The battery pack according to claim 1, wherein: Along the first direction, an area of ​​an overlapping portion of an orthographic projection of the first electrode assembly and an orthographic projection of the insulating layer is S1, an orthographic projection area of ​​the first electrode assembly is S2, and 0.3S2≤S1≤S2.

4. The battery pack according to claim 3, characterized in that: The first electrode assembly has a first surface, the first surface faces the insulating layer along the first direction, the area of ​​the first surface covered by the orthographic projection of the insulating layer along the first direction is the first area, and the remaining area is the second area; The second area is located in the middle of the first surface. When viewed along the first direction, the first surface has a first side, a second side, a third side and a fourth side. The first side and the second side are arranged opposite to each other along the second direction. The third side and the fourth side are arranged opposite to each other along the third direction. The first direction, the second direction and the third direction are perpendicular to each other. The second region has a first edge, a second edge, a third edge and a fourth edge, the first edge and the second edge are arranged opposite to each other along a second direction, the third edge and the fourth edge are arranged opposite to each other along a third direction, the first side and the first edge are located on the same side of the first electrode assembly, the second side and the second edge are located on the same side of the first electrode assembly, the third side and the third edge are located on the same side of the first electrode assembly, and the fourth side and the fourth edge are located on the same side of the electrode assembly; Along the second direction, the minimum distance from the first side to the second side is W1, the minimum distance from the first side to the first edge is D1, D1≥0.2W1, and the minimum distance from the second side to the second edge is D2, D2≥0.2W1; Along the third direction, the minimum distance from the third side to the fourth side is W2; the minimum distance from the third side to the third edge is D3, D3≥0.25W2, and the minimum distance from the fourth side to the fourth edge is D4, D4≥0.25W2.

5. The battery pack according to any one of claims 1 to 4, characterized in that: Along the first direction, the thickness of the insulating layer is T1, 0.1 mm≤T1≤10 mm.

6. The battery pack according to claim 5, characterized in that: 0.5mm≤T1≤1mm.

7. The battery pack according to any one of claims 1 to 4, characterized in that: Along the first direction, the thickness of the insulating layer is T1, the thickness of the first battery cell is T2, and 0.05≤T1 / T2≤1.

5.

8. The battery pack according to claim 1, wherein: The resistivity of the insulating layer is ρ, 100Ω·cm≤ρ≤10 25 Ω·cm.

9. The battery pack according to claim 8, characterized in that: 10 22 Ω·cm≤ρ≤10 25 Ohm cm.

10. The battery pack according to claim 1, wherein: The insulating layer is an insulating gel, and the material of the insulating gel includes at least one of polyethylene terephthalate, polybutylene terephthalate, polyarylate, bisphenol A epoxy resin, bisphenol F epoxy resin, polyphenol glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, polyisocyanate polyurethane, polyurethane resin, acrylic resin and modified resin thereof, polyalkyl silicone resin, polyaryl silicone resin, polyalkylaryl silicone resin, homopolymer polyesterimide resin, monoether polyesterimide resin, bisether anhydride polyesterimide resin, polyetherimide resin, polybismaleimide resin, nadic acid modified polyesterimide resin, polyamideimide resin, polybismaleimide, nadic acid terminated polyimide resin, natural rubber or synthetic rubber.

11. The battery pack according to claim 1, wherein: The insulating layer is a double-sided adhesive tape, and the double-sided adhesive tape includes a base material layer and adhesive layers arranged on both sides of the base material layer, and the adhesive layers are respectively bonded to the first electrode assembly and the second electrode assembly; The material of the substrate layer includes at least one of polyethylene terephthalate, polyimide, polyethylene, polypropylene, polyvinyl chloride, kraft paper, cotton cloth, synthetic fiber cloth, metal foil, and glass fiber; The material of the adhesive layer includes at least one of a rubber-based adhesive, a silicone-based adhesive, a hot melt adhesive, a water-based adhesive, a polyurethane-based adhesive, an epoxy-based adhesive, and a polyimide-based adhesive.

12. The battery pack according to claim 1, wherein: The insulating layer is an isolation membrane, which includes an isolation membrane substrate layer, and the material of the isolation membrane substrate layer includes at least one of polyethylene, polypropylene, polyimide, polyamide, polysulfone, polyacrylonitrile, polyester, cellulose, polyetheretherketone, polyphenylene sulfide, polyacrylate, polyethylene terephthalate, polyparaphenylamide, polyarylethersulfoneketone, aramid or aromatic sulfone.

13. The battery pack according to claim 12, characterized in that: The isolation film also includes an isolation film bonding layer arranged on at least one surface of the isolation film substrate layer, and the isolation film bonding layer is away from the isolation film substrate layer. The side of the isolation film bonding layer faces the first electrode assembly and / or the second electrode assembly, and the material of the isolation film bonding layer includes at least one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyimide, polyvinyl alcohol, sodium carboxymethyl cellulose, and acrylate.

14. An electrical device, characterized in that: A battery pack comprising the battery pack as claimed in any one of claims 1 to 13.

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