Shell and preparation method thereof, battery and electric equipment

Abstract

The invention discloses a shell and a preparation method thereof, a battery and electric equipment, the shell comprises a heat-conducting insulating layer, the heat-conducting insulating layer is arranged on at least part of the inner surface of the shell, the heat conductivity coefficient of the heat-conducting insulating layer is 0.03 W / mK to 10 W / mK, and the resistance of the heat-conducting insulating layer under the high voltage of 1000 V is 100 M omega to 100 G omega. Therefore, the heat conduction capability and the heat dissipation performance of the heat conduction insulating layer are improved, and the heat dissipation effect of the shell is improved.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular, to a shell and a preparation method thereof, a battery and an electrical device. Background Art

[0002] Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as in military equipment and aerospace and other fields. With the increase in battery energy density and the reduction in manufacturing costs, people have higher demands for battery charging speed. On the one hand, the increase in charging speed is conducive to market demand, but on the other hand, during fast charging, the greater the charging current, the more irreversible heat is generated inside the battery, and the electrode components cannot dissipate heat in time, resulting in an increase in battery surface temperature, increasing the risk of thermal runaway of the battery. Summary of the invention

[0003] In view of the technical problems existing in the background technology, the present application provides a shell, which can improve the heat dissipation effect of the shell and reduce the probability of thermal runaway of the battery.

[0004] A first aspect of the present application provides a shell, comprising a thermally conductive insulating layer, wherein the thermally conductive insulating layer is arranged on at least a portion of the inner surface of the shell, the thermal conductivity of the thermally conductive insulating layer is 0.03W / mK-10W / mK, and the resistance of the thermally conductive insulating layer under a high voltage of 1000V is 100MΩ-100GΩ.

[0005] The shell provided in the present application has a thermally conductive insulating layer on at least part of the inner surface of the shell. By making the thermal conductivity and resistance of the thermally conductive insulating layer within the above-mentioned ranges, the thermal conductivity and insulation properties of the thermally conductive insulating layer can be improved at the same time, while reducing the risk of short circuit inside the shell. When the battery temperature rises during fast charging, the heat dissipation rate of the shell can be increased, the heat dissipation effect of the shell can be improved, the temperature of the battery surface can be reduced, and the probability of thermal runaway of the battery can be reduced.

[0006] According to some embodiments of the present application, the thermal conductivity of the thermally conductive insulating layer is 0.2W / mK-10W / mK, and the resistance of the thermally conductive insulating layer under a high voltage of 1000V is 500MΩ-50GΩ. Thus, the thermal conductivity and insulation performance of the thermally conductive insulating layer are improved, and the heat dissipation effect of the housing is improved.

[0007] According to some embodiments of the present application, the leakage current of the thermally conductive insulation layer is 0-10 mA.

[0008] According to some embodiments of the present application, the leakage current of the thermally conductive insulation layer is 0.01 mA-1 mA.

[0009] Thus, by setting the leakage current of the thermally conductive insulating layer to be within the above range, the withstand voltage performance of the thermally conductive insulating layer is improved.

[0010] According to some embodiments of the present application, the thermally conductive insulating layer includes 1 to 50 parts by weight of a thermally conductive filler and 50 to 95 parts by weight of a prepolymer. Thus, by making the contents of the thermally conductive filler and the prepolymer within the above range, the insulation performance and thermal conductivity of the thermally conductive insulating layer can be improved, and the heat dissipation effect of the housing can be improved.

[0011] According to some embodiments of the present application, the content of the thermally conductive filler is 10 parts by weight to 30 parts by weight, and the content of the prepolymer is 70 parts by weight to 90 parts by weight, thereby improving the insulation performance and thermal conductivity of the thermally conductive insulation layer and improving the heat dissipation effect of the housing.

[0012] According to some embodiments of the present application, the thermally conductive filler includes at least one of inorganic particles having a dielectric constant of 5 or more and inorganic particles having ion conductivity but not storing ions. Thus, the thermal conductivity of the thermally conductive insulating layer is improved, and the heat dissipation effect of the housing is improved.

[0013] According to some embodiments of the present application, the inorganic particles having a dielectric constant of 5 or more include boehmite, aluminum oxide, zinc oxide, silicon oxide, titanium oxide, zirconium oxide, barium oxide, calcium oxide, magnesium oxide, nickel oxide, tin oxide, cerium oxide, yttrium oxide, hafnium oxide, aluminum hydroxide, magnesium hydroxide, silicon carbide, boron carbide, aluminum nitride, silicon nitride, boron nitride, magnesium fluoride, calcium fluoride, barium fluoride, barium sulfate, magnesium aluminum silicate, lithium magnesium silicate, sodium magnesium silicate, bentonite, hectorite, zirconium titanate, barium titanate, Pb(Zr,Ti)O3, Pb 1-m La m Zr 1-n Ti n O3、Pb(Mg 1 / 3 Nb 2 / 3 ) 3- At least one of PbTiO3 and its respective modified inorganic particles has 0<m<1 and 0<n<1. Thus, the thermal conductivity of the thermally conductive insulating layer is improved, and the heat dissipation effect of the housing is improved.

[0014] According to some embodiments of the present application, the inorganic particles having ion conductivity but not storing ions include Li3PO4, lithium titanium phosphate Li x 1Ti y1 (PO4)3, Lithium Aluminum Titanate Phosphate Li x2 Al y2 Ti z1 (PO4)3, (LiAlTiP) x3 O y3 Type glass, lanthanum titanate lithium Li x4 Lay4 TiO3, Lithium Germanium Phosphate Thiophosphate x5 Ge y5 P z2 S w 、Lithium Nitride Li x6 N y6 、SiS2 glass Li x7 Si y7 S z3 and P2S5 glass Li x8 P y8 S z4 At least one of 0<x1<2, 0<y1<3, 0<x2<2, 0<y2<1, 0<z1<3, 0<x3<4, 0<y3<13, 0<x4<2, 0<y4<3, 0<x5<4, 0<y5<1, 0<z2<1, 0<w<5, 0<x6<4, 0<y6<2, 0<x7<3, 0<y7<2, 0<z3<4, 0<x8<3, 0<y8<3, 0<z4<7. Thus, the thermal conductivity of the thermally conductive insulating layer is improved, and the heat dissipation effect of the shell is improved.

[0015] According to some embodiments of the present application, the prepolymer includes at least one of polyimide, phenolic resin, urea-formaldehyde resin or epoxy resin. Thus, the prepolymer of the above type can improve the insulation performance and electrolyte resistance of the thermally conductive insulating layer, and improve the stability of the thermally conductive insulating layer.

[0016] According to some embodiments of the present application, the thermally conductive insulating layer further comprises at least one of a dispersant and a curing agent, thereby improving the uniformity and curing rate of the thermally conductive insulating layer.

[0017] According to some embodiments of the present application, the dispersant includes at least one of sodium carboxymethyl cellulose, styrene-butadiene rubber, polyvinyl pyrrolidone, sodium lauryl sulfate, methyl amyl alcohol, polyacrylamide or guar gum. Thus, the uniformity of the thermally conductive insulating layer is improved, and then the insulation performance and thermal conductivity of the thermally conductive insulating layer are improved, and the heat dissipation effect of the shell is improved.

[0018] According to some embodiments of the present application, the curing agent includes at least one of hexamethylenetetramine, ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, p-phenylenediamine, m-phenylenediamine, terephthalic acid, terephthalic acid, maleic anhydride or phthalic anhydride, thereby increasing the curing rate of the thermally conductive insulating layer.

[0019] According to some embodiments of the present application, the thickness of the thermally conductive insulating layer is 1 μm-1000 μm.

[0020] According to some embodiments of the present application, the thickness of the thermally conductive insulating layer is 20 μm-200 μm.

[0021] Therefore, by setting the thickness of the heat-conductive insulating layer within the above range, the heat-conductive insulating layer can improve its thermal conductivity and insulation performance, thereby improving the heat dissipation effect of the housing.

[0022] According to some embodiments of the present application, the shell includes a bottom wall and a side wall, the side wall is connected to the edge of the bottom wall, the bottom wall and the side wall form a receiving cavity with an opening, and the thermally conductive insulating layer is provided on at least a portion of the inner surface of the side wall and the bottom wall. Thus, the shell can be used to accommodate the electrode assembly, and when the temperature of the electrode assembly rises during fast charging, the thermally conductive insulating layer can improve the heat dissipation capacity of the shell to the electrode assembly, reduce the accumulation of heat inside the shell, and reduce the risk of thermal runaway of the battery.

[0023] According to some embodiments of the present application, the thermally conductive insulating layer is provided on the entire inner surface of the side wall and the entire inner surface of the bottom wall. Thus, when the temperature of the electrode assembly rises during fast charging, the thermally conductive insulating layer can improve the heat dissipation capacity of the housing to the electrode assembly, reduce the accumulation of heat inside the housing, and reduce the risk of thermal runaway of the battery.

[0024] The second aspect of the present application provides a method for preparing a shell, comprising: forming a heat-conducting insulating layer on at least part of the inner surface of the shell, the thermal conductivity of the heat-conducting insulating layer is 0.03W / mK-10W / mK, and the resistance of the heat-conducting insulating layer under a high voltage of 1000V is 100MΩ-100GΩ. Thus, the prepared shell has excellent insulation and thermal conductivity, which can improve the heat dissipation effect of the shell. When the battery temperature rises during fast charging, the heat can be quickly dissipated from the shell, thereby improving the heat dissipation capacity of the shell, reducing the temperature of the battery surface, and reducing the probability of thermal runaway of the battery.

[0025] According to some embodiments of the present application, the method includes: mixing 1 to 50 parts by weight of a thermally conductive filler, 50 to 95 parts by weight of a prepolymer, and a solvent into a slurry, and forming the slurry on at least a portion of the inner surface of the housing to form the thermally conductive insulating layer. Thus, the thermal conductivity and insulating properties of the thermally conductive insulating layer are improved, and the electrolyte resistance of the thermally conductive insulating layer is improved.

[0026] According to some embodiments of the present application, the method further comprises: adding at least one of a dispersant and a curing agent into the slurry to form the thermally conductive insulating layer, thereby improving the uniformity and curing ability of the thermally conductive insulating layer.

[0027] According to some embodiments of the present application, the method further comprises: before forming the thermally conductive insulating layer, cleaning and activating the shell, thereby improving the bonding force between the thermally conductive insulating layer and the inner surface of the shell and reducing the risk of the thermally conductive insulating layer falling off.

[0028] The third aspect of the present application provides a battery, comprising the housing provided in the first aspect of the present application or the housing prepared by the method provided in the second aspect of the present application. Thus, the battery has excellent heat dissipation effect and can reduce the risk of thermal runaway of the battery.

[0029] According to some embodiments of the present application, the shell includes a bottom wall and a side wall, the side wall is connected to the edge of the bottom wall, the bottom wall and the side wall form a receiving cavity with an opening, the battery also includes a positive electrode sheet, a negative electrode sheet and a diaphragm, the positive electrode sheet, the negative electrode sheet and the diaphragm are located in the receiving cavity, the positive electrode sheet includes a positive electrode collector, the negative electrode sheet includes a negative electrode collector, the positive projection of the diaphragm on the side wall is located within the range of the positive projection of the negative electrode collector on the side wall and does not overlap, or the positive projection of the diaphragm on the side wall is located within the range of the positive projection of the positive electrode collector on the side wall and does not overlap; the inner surface of the bottom wall is provided with the thermally conductive insulating layer, and the thermally conductive insulating layer is in contact with the negative electrode collector or the positive electrode collector. Thus, while improving the heat dissipation effect of the shell, the risk of corrosion caused by the contact between the negative electrode collector or the positive electrode collector and the shell is reduced.

[0030] According to some embodiments of the present application, the orthographic projection of the separator on the side wall is within the range of the orthographic projection of the negative electrode current collector on the side wall and does not overlap, thereby reducing the risk of corrosion caused by the contact between the negative electrode current collector and the shell.

[0031] According to some embodiments of the present application, the negative electrode current collector includes a first region and a second region, the orthographic projection of the first region on the side wall coincides with the orthographic projection of the separator on the side wall, and the orthographic projection of the second region on the side wall is located within the orthographic projection range of the thermally conductive insulating layer on the side wall. Thus, the risk of short circuit caused by the contact between the negative electrode current collector and the shell is reduced.

[0032] According to some embodiments of the present application, along the extension direction of the negative electrode current collector, the length of the second region is D, and satisfies 1 mm≤D≤5 mm.

[0033] According to some embodiments of the present application, the end of the orthographic projection of the thermally conductive insulating layer on the side wall close to the opening of the accommodating cavity overlaps with the end of the orthographic projection of the diaphragm on the side wall away from the opening of the accommodating cavity, thereby reducing the risk of overlapping of the current collector and the shell.

[0034] According to some embodiments of the present application, along the extension direction of the negative electrode current collector, the height of the thermally conductive insulating layer on the side wall is H, and H is ≥ 5 mm, thereby reducing the risk of short circuit caused by the contact between the negative electrode current collector and the shell.

[0035] According to some embodiments of the present application, 1 cm ≤ H ≤ 3 cm, thereby reducing the risk of short circuit caused by the contact between the negative electrode current collector and the shell.

[0036] According to some embodiments of the present application, the battery includes: a top cover assembly, which is suitable for closing the opening of the accommodating cavity; the side walls are provided with the thermally conductive insulation layer, and the thermally conductive insulation layer is spaced apart from one end of the top cover assembly close to the top cover assembly and one end of the top cover assembly close to the shell.

[0037] According to some embodiments of the present application, the distance between one end of the thermally conductive insulating layer close to the top cover assembly and one end of the top cover assembly close to the shell is L, 2mm≤L≤5mm. Thus, when the top of the shell is welded, the influence of the thermally conductive insulating layer on welding is reduced.

[0038] The fourth aspect of the present application provides an electrical device, comprising the battery provided in the third aspect of the present application. Thus, the electrical device has excellent heat dissipation capability.

[0039] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0041] Figure 1 It is a schematic structural diagram of a shell according to one embodiment of the present application.

[0042] Figure 2 It is a schematic structural diagram of a shell of another embodiment of the present application.

[0043] Figure 3 Schematic diagram of a positive electrode current collector, a negative electrode current collector and a separator according to an embodiment of the present application.

[0044] Figure 4 It is a schematic structural diagram of a shell of another embodiment of the present application.

[0045] Figure 5 yes Figure 4 Magnified view of a local area.

[0046] Figure 6 It is a schematic structural diagram of a shell of another embodiment of the present application.

[0047] Figure 7is a schematic diagram of a battery according to one embodiment of the present application.

[0048] Figure 8 yes Figure 7 An exploded view of a battery according to an embodiment of the present application is shown.

[0049] Fig. 9 is a schematic diagram of a battery module according to an embodiment of the present application.

[0050] Fig.10 It is a schematic diagram of a battery pack according to one embodiment of the present application.

[0051] Fig.11 yes Fig.10 An exploded view of a battery pack according to an embodiment of the present application is shown.

[0052] Fig.12 It is a schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application.

[0053] Description of reference numerals:

[0054] 100: shell; 101: bottom wall; 102: side wall; 110: cover plate; 120: lower plastic; 130: thermally conductive insulating layer; 200: electrode assembly; 210: negative electrode current collector; A: first area; B: second area; 220: positive electrode current collector; 230: diaphragm; 1: battery pack; 2: upper box; 3: lower box; 4: battery module; 5 battery. DETAILED DESCRIPTION

[0055] The following is a detailed description of the embodiments of the technical solution of the present application. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0056] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0057] For simplicity, only some numerical ranges are specifically disclosed herein. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and any upper limit can be combined with any other upper limit to form an unspecified range. In addition, each separately disclosed point or single value can itself be combined as a lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unspecified range.

[0058] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0060] At present, from the perspective of market development, the application of batteries is becoming more and more extensive. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of battery application areas, its market demand is also constantly expanding.

[0061] The heat generated inside the battery includes reversible chemical heat caused by entropy change and irreversible Joule heat, among which Joule heat is proportional to the square of the current, that is, during fast charging, the greater the charging current, the more irreversible heat is generated inside the battery. Since the heat dissipation path inside the battery is long, the battery cannot dissipate heat in time. When the temperature accumulates to a certain level, side reactions will occur inside the battery, such as the decomposition of the solid electrolyte membrane (SEI membrane), and most of the side reactions occurring inside the battery are exothermic reactions, which will lead to further accumulation of heat and further increase the risk of thermal runaway of the battery.

[0062] The shell proposed in the present application is provided with a thermally conductive insulating layer on at least part of the inner surface of the shell. By making the thermal conductivity and resistance of the thermally conductive insulating layer within a certain range, the insulation performance and thermal conductivity of the thermally conductive insulating layer can be improved at the same time, the heat dissipation effect of the shell can be improved, and the risk of thermal runaway of the battery can be reduced.

[0063] The shell disclosed in the embodiment of the present application is suitable for lithium-ion batteries and sodium-ion batteries, and the battery disclosed in the embodiment of the present application can be used in various energy storage systems that use batteries as power sources or use batteries as energy storage elements. Electrical equipment may include, but is not limited to, mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.

[0064] A first aspect of the present application provides a shell, comprising a thermally conductive insulation layer, wherein the thermally conductive insulation layer is arranged on at least a portion of the inner surface of the shell, the thermal conductivity of the thermally conductive insulation layer is 0.03W / mK-10W / mK, and the resistance of the thermally conductive insulation layer under a high voltage of 1000V is 100MΩ-100GΩ.

[0065] The shell provided in the present application is provided with a thermally conductive insulating layer on at least part of the inner surface of the shell. By making the thermal conductivity and resistance of the thermally conductive insulating layer within the above-mentioned ranges, the thermal conductivity and insulation properties of the thermally conductive insulating layer can be improved at the same time, while preventing a short circuit from occurring inside the shell. The rate at which heat is transferred from the inside of the shell to the outside of the shell is increased, the heat dissipation effect of the shell is improved, the accumulation of heat inside the shell is reduced, the temperature of the battery surface is lowered, and the probability of thermal runaway of the battery is reduced.

[0066] According to some embodiments of the present application, the thermal conductivity of the thermally conductive insulating layer is 0.03W / mK-10W / mK, for example, it can be 0.03W / mK, 1W / mK, 2W / mK, 3W / mK, 4W / mK, 5W / mK, 6W / mK, 7W / mK, 8W / mK, 9W / mK or 10W / mK, etc., or it can be a range composed of any of the above numerical values. Thus, the thermal conductivity of the thermally conductive insulating layer is improved, and the heat inside the shell is quickly transferred to the outside of the shell, thereby improving the heat dissipation effect of the shell, reducing the accumulation of heat inside the shell, and reducing the risk of thermal runaway of the battery. According to some specific embodiments of the present application, the thermal conductivity of the thermally conductive insulating layer is 0.2W / mK-10W / mK.

[0067] In the present application, the thermal conductivity of the thermally conductive insulating layer is tested according to the GB / T10295-2008 test standard.

[0068] According to some embodiments of the present application, the resistance of the thermally conductive insulating layer under a high voltage of 1000V is 100MΩ-100GΩ, for example, it can be 100MΩ, 500MΩ, 1GΩ, 10GΩ, 20GΩ, 30GΩ, 40GΩ, 50GΩ, 60GΩ, 70GΩ, 80GΩ, 90GΩ or 100GΩ, etc., or it can be a range composed of any of the above numerical values. Thus, the insulation performance of the thermally conductive insulating layer is improved and the risk of short circuit in the shell is reduced. According to some specific embodiments of the present application, the resistance of the thermally conductive insulating layer under a high voltage of 1000V can be 500MΩ-50GΩ.

[0069] In the present application, the test method for the resistance of the thermally conductive insulating layer under a high voltage condition of 1000V is: using a withstand voltage tester, the negative pole of the withstand voltage tester is connected to the side of the shell body that is not provided with the thermally conductive insulating layer, and the positive pole of the withstand voltage tester is connected to the thermally conductive insulating layer on the shell body, and the test is performed in accordance with GB / T 1408.2-2016 to read the resistance value.

[0070] According to some embodiments of the present application, the leakage current of the thermally conductive insulating layer may be 0-10 mA, for example, 0, 1 mA, 2 mA, 3 mA, 4 mA, 5 mA, 6 mA, 7 mA, 8 mA, 9 mA or 10 mA, etc., or may be a range of any of the above values. Thus, while improving the thermal conductivity and insulation performance of the thermally conductive insulating layer, the withstand voltage of the thermally conductive insulating layer is improved. According to some specific embodiments of the present application, the leakage current of the thermally conductive insulating layer may be 0.01 mA-1 mA.

[0071] In this application, the leakage current of the thermally conductive insulation layer is tested according to GB / T 1408.2-2016.

[0072] According to some embodiments of the present application, the thermally conductive insulating layer may include 1 to 50 parts by weight of a thermally conductive filler and 50 to 95 parts by weight of a prepolymer. Thus, by making the contents of the thermally conductive filler and the prepolymer in the thermally conductive insulating layer within the above range, the thermal conductivity and insulation performance of the thermally conductive insulating layer are improved.

[0073] According to some embodiments of the present application, the thermally conductive insulating layer may include 1 to 50 parts by weight of a thermally conductive filler, for example, 1 part by weight, 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight or 50 parts by weight, etc., or may be a range consisting of any of the above numerical values. According to some specific embodiments of the present application, the thermally conductive insulating layer may include 10 to 30 parts by weight of a thermally conductive filler. Thus, by making the content of the thermally conductive filler within the above range, while improving the thermal conductivity of the thermally conductive insulating layer, the brittleness of the thermally conductive insulating layer is reduced, the mechanical strength and density of the thermally conductive insulating layer are improved, and the stability of the thermally conductive insulating layer is improved.

[0074] According to some embodiments of the present application, the thermally conductive insulating layer may include 50-95 parts by weight of prepolymer, for example, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight or 95 parts by weight, etc., or may be a range consisting of any of the above numerical values. According to some specific embodiments of the present application, the thermally conductive insulating layer may include 70-90 parts by weight of prepolymer. Thus, by making the content of the prepolymer within the above range, while improving the insulation performance of the thermally conductive insulating layer, the electrolyte resistance of the thermally conductive insulating layer is improved, the risk of the thermally conductive insulating layer falling off due to long-term immersion in the electrolyte is reduced, and the influence of the prepolymer on the thermal conductivity of the thermally conductive insulating layer is reduced.

[0075] According to some embodiments of the present application, the volume average particle size D of the thermal conductive filler is v 50 can be 50nm-2000nm, for example, 50nm, 100nm, 500nm, 1000nm, 1500nm or 2000nm, or can be a range of any of the above values. In this way, the uniformity of the thermally conductive filler in the thermally conductive insulating layer is improved, the thermal conductivity of the thermally conductive insulating layer as a whole is improved, the heat dissipation effect of the shell is improved, the temperature of the shell surface is reduced, and the risk of thermal runaway of the battery is reduced. According to some specific embodiments of the present application, the volume average particle size D of the thermally conductive filler is v 50 can be 100nm-1000nm.

[0076] In this application, the volume average particle size D v50 refers to the particle size corresponding to the cumulative volume distribution percentage reaching 50%, for example, referring to the standard GB / T 19077-2016 / ISO 13320:2009, using a laser particle size analyzer (MalvernMaster Size2000) for measurement. The specific test process is: take an appropriate amount of the sample to be tested (the sample concentration is sufficient to ensure 8%-12% shading), add 20ml of deionized water, and ultrasonicate for 5min (53KHz / 120W) to ensure that the sample is completely dispersed, and then measure the sample according to the GB / T19077-2016 / ISO 13320:2009 standard.

[0077] According to some embodiments of the present application, the thermally conductive filler includes at least one of inorganic particles having a dielectric constant of 5 or more and inorganic particles having ion conductivity but not storing ions. Thus, the thermal conductivity of the thermally conductive insulating layer is improved, and the heat dissipation effect of the housing is improved.

[0078] According to some embodiments of the present application, the inorganic particles having a dielectric constant of 5 or more include boehmite, aluminum oxide, zinc oxide, silicon oxide, titanium oxide, zirconium oxide, barium oxide, calcium oxide, magnesium oxide, nickel oxide, tin oxide, cerium oxide, yttrium oxide, hafnium oxide, aluminum hydroxide, magnesium hydroxide, silicon carbide, boron carbide, aluminum nitride, silicon nitride, boron nitride, magnesium fluoride, calcium fluoride, barium fluoride, barium sulfate, magnesium aluminum silicate, lithium magnesium silicate, sodium magnesium silicate, bentonite, hectorite, zirconium titanate, barium titanate, Pb(Zr,Ti)O3, Pb 1-m La m Zr 1-n Ti n O3、Pb(Mg 1 / 3 Nb 2 / 3 ) 3- At least one of PbTiO3 and its respective modified inorganic particles has 0<m<1 and 0<n<1. Thus, the thermal conductivity of the thermally conductive insulating layer is improved, and the heat dissipation effect of the housing is improved.

[0079] According to some embodiments of the present application, the inorganic particles having ion conductivity but not storing ions include Li3PO4, lithium titanium phosphate Li x 1Ti y1 (PO4)3, Lithium Aluminum Titanate Phosphate Li x2 Al y2 Ti z1 (PO4)3, (LiAlTiP) x3 O y3 Type glass, lanthanum titanate lithium Li x4 La y4 TiO3, Lithium Germanium Phosphate Thiophosphate x5 Ge y5 P z2S w 、Lithium Nitride Li x6 N y6 、SiS2 glass Li x7 Si y7 S z3 and P2S5 glass Li x8 P y8 S z4 At least one of 0<x1<2, 0<y1<3, 0<x2<2, 0<y2<1, 0<z1<3, 0<x3<4, 0<y3<13, 0<x4<2, 0<y4<3, 0<x5<4, 0<y5<1, 0<z2<1, 0<w<5, 0<x6<4, 0<y6<2, 0<x7<3, 0<y7<2, 0<z3<4, 0<x8<3, 0<y8<3, 0<z4<7. Thus, the thermal conductivity of the thermally conductive insulating layer is improved, and the heat dissipation effect of the shell is improved.

[0080] According to some embodiments of the present application, the weight average molecular weight of the prepolymer can be 500-10000, for example, 500, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000 or 10000, or the like, or a range consisting of any of the above numerical values. Thus, the brittleness of the polymer is reduced. According to some specific embodiments of the present application, the weight average molecular weight of the prepolymer can be 1000-5000.

[0081] According to some embodiments of the present application, the prepolymer may include at least one of polyimide, phenolic resin, urea-formaldehyde resin or epoxy resin. Thus, the prepolymer of the above type can improve the insulation performance of the thermally conductive insulating layer and reduce the risk of short circuit in the housing.

[0082] According to some embodiments of the present application, the thermally conductive insulating layer may further include a dispersant, and the content of the dispersant may be 0.1 parts by weight to 10 parts by weight, for example, 0.1 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight or 10 parts by weight, or the like, or may be a range of any of the above numerical values. Thus, the uniformity of the thermally conductive filler in the prepolymer is improved, and the probability of agglomeration of the thermally conductive filler in the prepolymer is reduced. According to some specific embodiments of the present application, the content of the dispersant may be 0.5 parts by weight to 5 parts by weight.

[0083] According to some embodiments of the present application, the dispersant may include at least one of sodium carboxymethyl cellulose, styrene-butadiene rubber, polyvinyl pyrrolidone, sodium lauryl sulfate, methyl amyl alcohol, polyacrylamide or guar gum. Thus, the above-mentioned dispersants can improve the uniformity of the dispersion of the thermal conductive filler in the prepolymer and reduce the probability of agglomeration of the thermal conductive filler in the prepolymer.

[0084] According to some embodiments of the present application, the thermally conductive insulating layer may further include a curing agent, and the content of the curing agent may be 1-20 parts by weight, for example, 1 part by weight, 3 parts by weight, 5 parts by weight, 7 parts by weight, 9 parts by weight, 11 parts by weight, 13 parts by weight, 15 parts by weight, 17 parts by weight or 20 parts by weight, or may be a range of any of the above numerical values. Thus, the efficiency of curing the thermally conductive insulating layer on the housing is improved. According to some specific embodiments of the present application, the content of the curing agent may be 5-10 parts by weight.

[0085] According to some embodiments of the present application, the curing agent may include at least one of hexamethylenetetramine, ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, p-phenylenediamine, m-phenylenediamine, terephthalic acid, terephthalic acid, maleic anhydride or phthalic anhydride. Thus, the curing efficiency of the thermally conductive insulating layer can be improved by adding the above-mentioned curing agents to the thermally conductive insulating layer.

[0086] According to some specific embodiments of the present application, the thermally conductive insulating layer comprises 1 to 50 parts by weight of a thermally conductive filler, 50 to 95 parts by weight of a prepolymer, 0.1 to 10 parts by weight of a dispersant, and 1 to 20 parts by weight of a curing agent. Thus, while improving the thermal conductivity and insulation performance of the thermally conductive insulating layer, the probability of agglomeration of the thermally conductive filler in the prepolymer is reduced, thereby improving the curing efficiency of the thermally conductive insulating layer.

[0087] According to some specific embodiments of the present application, the thickness of the thermally conductive insulating layer may be 1 μm-1000 μm, for example, 1 μm, 10 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1000 μm, etc., or may be a range composed of any of the above numerical values. Thus, while improving the thermal conductivity and insulation performance of the thermally conductive insulating layer, the space of the shell occupied by the thermally conductive insulating layer is reduced, and the energy density of the battery is improved. According to some specific embodiments of the present application, the thickness of the thermally conductive insulating layer may be 20 μm-200 μm.

[0088] The thickness of the thermally conductive insulating layer in this application is tested according to ISO2360 standard.

[0089] According to some embodiments of the present application, reference Figure 1The housing 100 may include a bottom wall 101 and a side wall 102, wherein the side wall 102 is connected to the edge of the bottom wall 101, the bottom wall 101 and the side wall 102 form a receiving cavity with an opening, and the heat-conducting insulating layer 130 is provided on a part of the inner surface of the side wall 102 and the bottom wall 101. Thus, the heat dissipation effect of the housing 100 is improved, the temperature of the surface of the housing 100 is reduced, and the risk of thermal runaway of the battery is reduced.

[0090] According to some embodiments of the present application, the thermally conductive insulating layer is disposed on the entire inner surface of the side wall and the entire inner surface of the bottom wall. Thus, when the battery temperature rises, the heat can be quickly dissipated from the housing 100, thereby improving the heat dissipation capacity of the housing 100, reducing the temperature of the battery surface, and reducing the probability of thermal runaway of the battery.

[0091] The second aspect of the present application provides a method for preparing a shell, comprising: forming a heat-conducting insulating layer on at least part of the inner surface of the shell, the thermal conductivity of the heat-conducting insulating layer is 0.03W / mK-10W / mK, and the resistance of the heat-conducting insulating layer under a high voltage of 1000V is 100MΩ-100GΩ. Thus, the prepared shell 100 has excellent insulation and thermal conductivity, which can improve the heat dissipation effect of the shell 100. When the battery temperature rises during fast charging, the heat can be quickly dissipated from the shell 100, thereby improving the heat dissipation capacity of the shell 100, reducing the temperature of the battery surface, and reducing the probability of thermal runaway of the battery.

[0092] According to some embodiments of the present application, the thermally conductive insulating layer may be formed by single-layer coating or multi-layer coating.

[0093] According to some embodiments of the present application, the thermally conductive insulating layer may be formed by at least one of spray coating, dip coating, flow coating or blade coating.

[0094] According to some embodiments of the present application, the method includes: mixing 1 to 50 parts by weight of a thermally conductive filler, 50 to 95 parts by weight of a prepolymer, and a solvent into a slurry, and forming the slurry on the housing to form the thermally conductive insulating layer. Thus, the insulation performance and thermal conductivity of the thermally conductive insulating layer are improved, and the heat dissipation effect of the housing is improved.

[0095] According to some embodiments of the present application, the content of the solvent in the slurry can be 30 parts by weight to 90 parts by weight, for example, 30 parts by weight, 40 parts by weight, 50 parts by weight, 60 parts by weight, 70 parts by weight, 80 parts by weight or 90 parts by weight, or can be a range of any of the above values. Thus, the uniformity of the slurry is improved, the thermal conductivity and insulation performance of the thermally conductive insulating layer as a whole are improved, the electrolyte resistance of the thermally conductive insulating layer is improved, the probability of the thermally conductive insulating layer falling off is reduced, the risk of thermal runaway of the battery is reduced, and the service life of the battery is increased.

[0096] According to some embodiments of the present application, the method further comprises: adding at least one of a dispersant and a curing agent into the slurry to form the thermally conductive insulating layer, thereby improving the uniformity and curing ability of the thermally conductive insulating layer.

[0097] According to some embodiments of the present application, the method includes: mixing 1 to 50 parts by weight of a thermally conductive filler, 50 to 95 parts by weight of a prepolymer, 0.1 to 10 parts by weight of a dispersant, 5 to 10 parts by weight of a curing agent, and a solvent into a slurry, and forming the slurry on the housing to form the thermally conductive insulating layer. Thus, the insulation performance and thermal conductivity of the thermally conductive insulating layer are improved, and the heat dissipation effect of the housing is improved.

[0098] According to some embodiments of the present application, the solvent may include at least one of water, methanol, ethanol, n-butanol, acetone, and N-methylpyrrolidone.

[0099] According to some embodiments of the present application, the slurry can form the thermally conductive insulating layer by thermal curing, and the thermal curing temperature can be 100°C-200°C, for example, it can be 100°C, 120°C, 140°C, 160°C, 180°C or 200°C, etc., or it can be a range composed of any of the above numerical values.

[0100] According to some embodiments of the present application, the method further includes: before forming the thermally conductive insulating layer, cleaning and activating the shell. Specifically, the oil and impurities on the shell surface can be removed by at least one of plasma surface cleaning, acid cleaning or alkaline cleaning, so that the surface of the shell is rich in active groups such as -OH and -COOH, which can react with active groups such as -OH, -COOH, -NH2, and -C2H4O in the thermally conductive insulating layer slurry, and the thermally conductive insulating layer is bonded to the surface of the shell through covalent bonds, thereby improving the bonding force between the thermally conductive insulating layer and the shell, and reducing the risk of the thermally conductive insulating layer falling off when immersed in high temperature or electrolyte for a long time.

[0101] The third aspect of the present application provides a battery, comprising the housing provided in the first aspect of the present application or the housing prepared by the method provided in the second aspect of the present application. Thus, the heat dissipation effect of the battery housing can be improved, the temperature of the battery surface can be reduced, and the risk of thermal runaway of the battery can be reduced.

[0102] According to some embodiments of the present application, reference Figure 2 and Figure 3The housing 100 includes a bottom wall 101 and a side wall 102, wherein the side wall 102 is connected to the edge of the bottom wall 101, and the bottom wall 101 and the side wall 102 form a receiving cavity with an opening. The battery 5 also includes a positive electrode sheet, a negative electrode sheet and a separator 230, wherein the positive electrode sheet, the negative electrode sheet and the separator 230 are located in the receiving cavity, the positive electrode sheet includes a positive electrode collector 220, the negative electrode sheet includes a negative electrode collector 210, and the separator The orthographic projection of the separator 230 on the side wall 102 is within the range of the orthographic projection of the negative electrode collector 210 on the side wall 102 and does not overlap, or the orthographic projection of the separator 230 on the side wall 102 is within the range of the orthographic projection of the positive electrode collector 220 on the side wall 102 and does not overlap; the inner surface of the bottom wall 101 is provided with the thermally conductive insulating layer 130, and the thermally conductive insulating layer 130 is in contact with the negative electrode collector 210 or the positive electrode collector 220. Specifically, an insulating film (not shown in the figure) is provided on the outer surface of the electrode assembly 200 to insulate the electrode assembly 200 from the housing 100, and a heat-conducting insulating layer 130 is provided between the negative electrode current collector 210 and the bottom wall 101 of the housing 100 and the side wall 102 of the housing 100. The heat generated inside the battery 5 can be directly dissipated to the outside of the battery 5 through the negative electrode current collector 210, the heat-conducting insulating layer 130 and the bottom wall 101 of the housing, while improving the heat dissipation effect of the housing 100, and reducing the risk of corrosion caused by the contact between the negative electrode current collector 210 and the bottom wall 101 of the housing 100; or a heat-conducting insulating layer 130 is provided between the positive electrode current collector 220 and the bottom wall 101 of the housing 100 and the side wall 102 of the housing 100. As a result, the heat generated inside the battery 5 can be directly dissipated to the outside of the battery 5 through the positive electrode current collector 220, the heat-conducting insulating layer 130 and the bottom wall 101 of the housing, thereby improving the heat dissipation effect of the housing 100.

[0103] According to some embodiments of the present application, the orthographic projection of the separator 230 on the side wall is located within the range of the orthographic projection of the negative electrode current collector 210 on the side wall and does not overlap.

[0104] According to some embodiments of the present application, reference Figure 4 When the inner surface of the side wall 102 of the shell 100 is provided with the thermally conductive insulating layer 130, the thermally conductive insulating layer 130 can insulate the electrode assembly 200 from the shell 100, without providing an insulating film on the outer surface of the electrode assembly 200, thereby reducing the volume occupied by the electrode assembly 200 and improving the energy density of the battery 5.

[0105] According to some embodiments of the present application, reference Figure 3, the negative electrode current collector 210 includes a first region A and a second region B, the orthographic projection of the first region A on the side wall 102 coincides with the orthographic projection of the diaphragm on the side wall 102, and the orthographic projection of the second region B on the side wall 102 is located within the orthographic projection range of the thermally conductive insulating layer 130 on the side wall 102. Specifically, the size of the first region A of the negative electrode current collector 210 may be the same as that of the diaphragm, the second region B of the negative electrode current collector 210 extends toward the bottom wall 101 of the housing 100, and the thermally conductive insulating layer 130 is provided between the second region B and the bottom wall 101 of the housing 100. Thus, the heat generated inside the battery 5 can be directly dissipated to the outside of the battery 5 through the negative electrode current collector 210, the thermally conductive insulating layer 130 and the bottom wall 101 of the housing, while improving the heat dissipation effect of the housing 100, and reducing the risk of corrosion caused by the contact between the negative electrode current collector 210 and the bottom wall 101 of the housing 100.

[0106] According to some embodiments of the present application, reference Figure 3 , along the extension direction of the negative electrode current collector 210, the length of the second region B is D, and satisfies 1mm≤D≤5mm, for example, it can be 1mm, 2mm, 3mm, 4mm or 5mm, etc., or can be a range composed of any of the above values.

[0107] According to some embodiments of the present application, the end of the orthographic projection of the thermally conductive insulating layer 130 on the side wall 102 close to the opening of the accommodating cavity overlaps with the end of the orthographic projection of the diaphragm 230 on the side wall away from the opening of the accommodating cavity, thereby reducing the risk of overlapping between the current collector and the shell.

[0108] According to some embodiments of the present application, reference Figure 2 , along the extension direction of the negative electrode current collector 210, the height of the thermally conductive insulating layer 130 on the side wall 102 is H, H ≥ 5mm, for example, it can be 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm or 40mm, or it can be a range of any of the above values. Thus, while improving the heat dissipation effect, the content of active material on the negative electrode sheet is increased, and the energy density of the battery 5 is increased. According to some specific embodiments of the present application, 1cm ≤ H ≤ 3cm.

[0109] According to some embodiments of the present application, the battery includes: a top cover assembly, the top cover assembly is suitable for closing the opening of the accommodating cavity; the side wall 102 is provided with the thermally conductive insulating layer 130, and the end of the thermally conductive insulating layer 130 close to the top cover assembly is spaced apart from the end of the top cover assembly close to the shell 100. Therefore, when the shell 100 and the top cover assembly are welded, the influence of the thermally conductive insulating layer 130 on the welding is reduced.

[0110] According to some embodiments of the present application, reference Figure 4-Figure 6 , the distance between the end of the heat-conducting insulating layer 130 close to the top cover assembly and the end of the top cover assembly close to the shell 100 is L, 2mm≤L≤5mm, for example, it can be 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, or it can be a range composed of any of the above values. Specifically, when the top of the shell 100 is provided with a lower plastic 120 and a cover plate 110, by making the value of L within the above range, when the shell 100 and the top cover assembly are welded, the influence of the heat-conducting insulating layer 130 on the welding can be reduced.

[0111] [Positive electrode]

[0112] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector.

[0113] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is disposed on any one or both of the two facing surfaces of the positive electrode current collector.

[0114] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0115] In some embodiments, when the battery is a lithium-ion battery, the positive electrode active material may adopt a positive electrode active material for lithium-ion batteries that is well known in the art. As an example, the positive electrode active material may include at least one of the following materials: a lithium-containing phosphate with an olivine structure, a lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333)、LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.8 Co 0.15 Al 0.05 O2) and its modified compounds, etc. Examples of lithium-containing phosphates with an olivine structure may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0116] For example, when the battery is a sodium ion battery, as an example, the positive electrode active material may include but is not limited to at least one of a layered transition metal oxide, a polyanion compound, and a Prussian blue analog.

[0117] Examples of the layered transition metal oxides include:

[0118] Na 1-x Cu h Fe k Mn l M 1 m O 2-y , where M 1 It is one or more of Li, Be, B, Mg, Al, K, Ca, Ti, Co, Ni, Zn, Ga, Sr, Y, Nb, Mo, In, Sn and Ba, 0 <x≤0.33,0<h≤0.24,0≤k≤0.32,0<l≤0.68,0≤m<0.1,h+k+l+m=1,0≤y<0.2;

[0119] Na 0.67 Mn 0.7 Ni z M 2 0.3-z O2, where M2 is one or more of Li, Mg, Al, Ca, Ti, Fe, Cu, Zn and Ba, and 0 < z ≤ 0.1;

[0120] Na a Li b Ni c Mn d Fe e O2, where 0.67 < a ≤ 1, 0 < b < 0.2, 0 < c < 0.3, 0.67 < d + e < 0.8, and b + c + d + e = 1.

[0121] As an example of the above polyanion compound, for example, the following can be listed:

[0122] A 1 f M 3 g (PO4) i O j X 1 3-j , where A 1 is one or more of H, Li, Na, K and NH4, M 3 is one or more of Ti, Cr, Mn, Fe, Co, Ni, V, Cu and Zn, X 1 is one or more of F, Cl and Br, 0 < f ≤ 4, 0 < g ≤ 2, 1 ≤ i ≤ 3, 0 ≤ j ≤ 2;

[0123] Na n M 4 PO4X 2 , where M 4 is one or more of Mn, Fe, Co, Ni, Cu and Zn, X 2 is one or more of F, Cl and Br, 0 < n ≤ 2;

[0124] Na p M 5 q (SO4)3, where M 5 is one or more of Mn, Fe, Co, Ni, Cu and Zn, 0 < p ≤ 2, 0 < q ≤ 2;

[0125] Na s Mn t Fe 3-t (PO4)2(P2O7), where 0 < s ≤ 4, 0 ≤ t ≤ 3, for example, t is 0, 1, 1.5, 2 or 3.

[0126] As an example of the above Prussian blue analog, for example, the following can be listed:

[0127] A u M 6 v [M 7 (CN)6] w ·xH2O, wherein A is H + 、NH4 + 、an alkali metal cation, or an alkaline earth metal cation, or one or more of them, M 6 and M 7 are each independently one or more of transition metal cations, 0 < u ≤ 2, 0 < v ≤ 1, 0 < w ≤ 1, 0 < x < 6. For example, A is H + 、Li + 、Na + 、K + 、NH4 + 、Rb + 、Cs + 、Fr + 、Be 2+ 、Mg 2+ 、Ca 2+ 、Sr 2+ 、Ba 2+ and Ra 2+ 、or one or more of them, M 6 and M 7 are each independently cations of one or more transition metal elements selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, and W.

[0128] The modified compounds of the above materials may be doping modification and / or surface coating modification of the materials.

[0129] In some embodiments, the positive electrode active material layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0130] In some embodiments, the positive electrode active material layer may further optionally include a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0131] In some embodiments, the positive electrode sheet can be prepared in the following manner: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0132] [Negative electrode]

[0133] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode active material layer includes a negative electrode active material.

[0134] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material layer is disposed on any one or both of the two facing surfaces of the negative electrode current collector.

[0135] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, copper foil may be used. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0136] In some embodiments, the negative electrode active material may adopt the negative electrode active material for the battery known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0137] In some embodiments, the negative electrode active material layer may further include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).

[0138] In some embodiments, the negative electrode active material layer may further include a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0139] In some embodiments, the negative electrode active material layer may further optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0140] In some embodiments, the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0141] [Electrolytes]

[0142] The electrolyte plays a role in conducting ions between the positive electrode and the negative electrode. The present application has no specific restrictions on the type of electrolyte, which can be selected according to needs.

[0143] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.

[0144] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0145] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.

[0146] In some embodiments, the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.

[0147] [Isolation film]

[0148] In some embodiments, the battery further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical stability and mechanical stability can be selected.

[0149] In some embodiments, the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0150] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.

[0151] The present application has no particular limitation on the shape of the battery, which may be cylindrical, square or any other shape. For example, Figure 7 The battery 5 is a square structure as an example.

[0152] In some embodiments, reference Figure 8 The outer package may include a shell 100 and a cover plate 110. The positive electrode sheet, the negative electrode sheet and the separator may form an electrode assembly 200 through a winding process or a lamination process. The electrode assembly 200 is encapsulated in the accommodating cavity. The electrolyte is infiltrated in the electrode assembly 200. The number of electrode assemblies 200 contained in the battery 5 may be one or more, and those skilled in the art may select according to specific actual needs.

[0153] In some embodiments, batteries may be assembled into a battery module. The number of batteries contained in the battery module may be one or more. The specific number may be selected by those skilled in the art according to the application and capacity of the battery module.

[0154] Fig. 9 4 is an example of a battery module. Fig. 9 In the battery module 4, the multiple batteries 5 can be arranged in sequence along the length direction of the battery module 4. Of course, they can also be arranged in any other manner. Further, the multiple batteries 5 can be fixed by fasteners.

[0155] Optionally, the battery module 4 may further include a housing having a receiving space, and the plurality of batteries 5 are received in the receiving space.

[0156] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.

[0157] Fig.10 and Fig.11 1 is a battery pack 1 as an example. Fig.10 and Fig.11 The battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery modules 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0158] The fourth aspect of the present application provides an electric device, the electric device comprising the battery provided in the third aspect of the present application. The electric device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but is not limited thereto.

[0159] Fig.12 The power consumption device is taken as an example. The power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the power consumption device's requirements for high power and high energy density of the battery, a battery pack or a battery module can be used.

[0160] As another example, the device may be a mobile phone, a tablet computer, a notebook computer, etc. The device is usually required to be light and thin, and a battery may be used as a power source.

[0161] In order to make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail with reference to the embodiments and the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its applications. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0162] Example 1

[0163] 1. Preparation of positive electrode sheet

[0164] The positive electrode active material LiFePO4, the conductive agent carbon black (Super P), and the binder polyvinylidene fluoride (PVDF) are fully stirred and mixed in a proper amount of solvent N-methylpyrrolidone (NMP) at a mass ratio of 80:15:5 to form a uniform positive electrode slurry; the positive electrode slurry is evenly coated on the surface of the positive electrode current collector aluminum foil, and after drying and cold pressing, a positive electrode sheet is obtained.

[0165] 2. Preparation of negative electrode sheet

[0166] Kuraray Type 1 hard carbon is used as the negative electrode active material. The hard carbon negative electrode active material, conductive agent carbon black (Super P), and binder carboxymethyl cellulose (CMC) are fully stirred and mixed in a proper amount of solvent deionized water at a mass ratio of 90:5:5 to form a uniform negative electrode slurry; the negative electrode slurry is evenly coated on the surface of the negative electrode current collector aluminum foil, and after drying and cold pressing, a negative electrode sheet is obtained.

[0167] 3. Preparation of electrolyte

[0168] Ethylene carbonate (EC) and diethyl carbonate (DEC) are mixed in equal volumes to obtain an organic solvent, and then NaPF6 is dissolved in the organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0169] 4. Isolation film

[0170] A porous polyethylene membrane was used as the separator.

[0171] 5. Preparation of electrode assembly

[0172] The positive electrode sheet, the separator, and the negative electrode sheet are wound in sequence so that the separator is located between the positive electrode sheet and the negative electrode sheet to play an isolating role, thereby obtaining an electrode assembly.

[0173] 6. Prepare the shell

[0174] The thermal conductive filler, prepolymer, curing agent and dispersant are fully stirred and mixed in a suitable amount of solvent in a mass ratio of 2:89:2:7 to form a uniform slurry, and the slurry is applied to the bottom and side walls of the shell, wherein the side wall coating height H is 5 mm. After heating and curing, a shell with a thermal conductive insulating layer attached to the inner wall is obtained.

[0175] 7. Assemble the electrode assembly and the shell.

[0176] The preparation methods of the batteries and shells in Examples 2 to 25 and Comparative Examples 1 to 4 are the same as those in Example 1, and the differences are detailed in Table 1.

[0177]

[0178]

[0179]

[0180] Performance Testing

[0181] 1. Thermal conductivity test method

[0182] Test standard GB / T10295-2008

[0183] 2. Resistance test method

[0184] Use a withstand voltage tester, connect the negative pole of the withstand voltage tester to the shell without a thermal insulation layer, and connect the positive pole of the withstand voltage tester to the thermal insulation layer. Perform the test in accordance with GB / T 1408.2-2016 and read the resistance value.

[0185] 3. Leakage current test method

[0186] Use a withstand voltage tester, connect the negative electrode of the withstand voltage tester to the side of the shell body not provided with the thermally conductive insulating layer, and connect the positive electrode of the withstand voltage tester to the thermally conductive insulating layer on the shell body. Test according to GB / T 1408.2-2016 and read the resistance value.

[0187] 4. Test method for corrosion of exterior test

[0188] The shell is assembled with an electrode assembly, the battery is charged to a state of charge (SOC) of 33%, a wire is used to connect the negative electrode and the shell, the battery is left to stand for 10 days, the shell is disassembled and the corrosion condition is observed.

[0189] 5. Electrolyte resistance test

[0190] Place the shell with a thermal insulating layer in the electrolyte. After immersing the shell at 60°C for 1500 hours, overlap the negative electrode of the withstand voltage tester with the side of the shell without a thermal insulating layer, and overlap the positive electrode with the thermal insulating layer on the shell. The given voltage DC is 2700V and the test time is 60s. Determine whether the film layer is broken down. Repeat 25 times.

[0191] 6. 4C fast charging heat dissipation experiment

[0192] The shell with a thermal insulating layer was assembled with the electrode assembly, and the battery was charged and discharged for 10 cycles at a rate of 4C, and the temperature of the large surface of the battery was recorded.

[0193] 7. Voltage test after immersion in electrolyte

[0194] Take out the sample soaked in electrolyte, dip it in ethanol to clean the residual electrolyte on the surface, turn on the voltage tester, overlap the negative electrode with the side of the shell without the thermal conductive insulation layer, overlap the positive electrode with the thermal conductive insulation layer on the shell, give a voltage DC of 2700V, test time of 60s, and judge whether the film layer is broken down.

[0195] The test results of Examples 1 to 25 and Comparative Examples 1 to 4 are shown in Table 2.

[0196] Table 2

[0197]

[0198]

[0199] Conclusion: It can be seen from Examples 1 to 25 and Comparative Examples 1 to 4 that the battery assembled into the shell proposed in the present application can simultaneously reduce the temperature of the large surface of the battery cell, improve the pressure resistance of the thermal conductive insulation layer, and reduce the probability of corrosion caused by the contact between the positive electrode collector or the negative electrode collector and the bottom wall of the shell.

[0200] 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 them; 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 by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A housing, characterized in that: include: A heat-conducting insulating layer is provided on at least a portion of the inner surface of the shell, the thermal conductivity of the heat-conducting insulating layer is 0.03W / mK-10W / mK, and the resistance of the heat-conducting insulating layer under a high voltage of 1000V is 100MΩ-100GΩ.

2. The housing according to claim 1, characterized in that The thermal conductivity of the thermally conductive insulating layer is 0.2W / mK-10W / mK, and the resistance of the thermally conductive insulating layer under a high voltage of 1000V is 500MΩ-50GΩ.

3. The housing according to claim 1 or 2, characterized in that: The leakage current of the thermally conductive insulating layer is 0-10 mA, and can be optionally 0.01 mA-1 mA.

4. The housing according to any one of claims 1 to 3, characterized in that: The thermally conductive insulating layer comprises 1 to 50 parts by weight of a thermally conductive filler and 50 to 95 parts by weight of a prepolymer.

5. The housing according to any one of claims 1 to 4, characterized in that: The thermally conductive insulating layer comprises 10 to 30 parts by weight of a thermally conductive filler and 70 to 90 parts by weight of a prepolymer.

6. The housing according to claim 4 or 5, characterized in that: The thermally conductive filler includes at least one of inorganic particles having a dielectric constant of 5 or more and inorganic particles having ion conductivity but not storing ions.

7. The housing according to claim 6, characterized in that Satisfy at least one of the following conditions: The inorganic particles having a dielectric constant of 5 or more include boehmite, aluminum oxide, zinc oxide, silicon oxide, titanium oxide, zirconium oxide, barium oxide, calcium oxide, magnesium oxide, nickel oxide, tin oxide, cerium oxide, yttrium oxide, hafnium oxide, aluminum hydroxide, magnesium hydroxide, silicon carbide, boron carbide, aluminum nitride, silicon nitride, boron nitride, magnesium fluoride, calcium fluoride, barium fluoride, barium sulfate, magnesium aluminum silicate, lithium magnesium silicate, sodium magnesium silicate, bentonite, hectorite, zirconium titanate, barium titanate, Pb(Zr,Ti)O3, Pb 1-m La m Zr 1-n Ti n O3、Pb(Mg 1 / 3 Nb 2 / 3 ) at least one of O3PbTiO3 and their respective modified inorganic particles, 0<m<1, 0<n<1; The inorganic particles having ion conductivity but not storing ions include Li3PO4, lithium titanium phosphate Li x 1Ti y1 (PO4)3, Lithium Aluminum Titanate Phosphate Li x2 Al y2 Ti z1 (PO4)3, (LiAlTiP) x3 O y3 Type glass, lanthanum titanate lithium Li x4 La y4 TiO3, Lithium Germanium Phosphate Thiophosphate x5 Ge y5 P z2 S w 、Lithium Nitride Li x6 N y6 、SiS2 glass Li x7 Si y7 S z3 and P2S5 glass Li x8 P y8 S z4 At least one of the following, 0<x1<2, 0<y1<3, 0<x2<2, 0<y2<1, 0<z1<3, 0<x3<4, 0<y3<13, 0<x4<2, 0<y4<3, 0<x5<4, 0<y5<1, 0<z2<1, 0<w<5, 0<x6<4, 0<y6<2, 0<x7<3, 0<y7<2, 0<z3<4, 0<x8<3, 0<y8<3, 0<z4<7.

8. The housing according to any one of claims 4 to 7, characterized in that: The prepolymer includes at least one of polyimide, phenolic resin, urea-formaldehyde resin or epoxy resin.

9. The housing according to any one of claims 4 to 8, characterized in that: The thermally conductive insulating layer further includes at least one of a dispersant and a curing agent.

10. The housing according to claim 9, characterized in that Satisfy at least one of the following conditions: The dispersant comprises at least one of sodium carboxymethyl cellulose, styrene-butadiene rubber, polyvinyl pyrrolidone, sodium lauryl sulfate, methyl amyl alcohol, polyacrylamide or guar gum; The curing agent includes at least one of hexamethylenetetramine, ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, p-phenylenediamine, m-phenylenediamine, terephthalic acid, terephthalic acid, maleic anhydride or phthalic anhydride.

11. The housing according to any one of claims 1 to 10, characterized in that: The thickness of the thermally conductive insulating layer is 1 μm-1000 μm, and can be optionally 20 μm-200 μm.

12. The housing according to any one of claims 1 to 11, characterized in that: The shell includes a bottom wall and a side wall, the side wall is connected to the edge of the bottom wall, the bottom wall and the side wall form a receiving cavity with an opening, and the thermal conductive insulation layer is arranged on at least part of the inner surface of the side wall and the bottom wall.

13. The housing according to claim 12, characterized in that The thermally conductive insulating layer is disposed on the entire inner surface of the side wall and the entire inner surface of the bottom wall.

14. A method for preparing a housing, characterized in that: include: A heat-conducting insulating layer is formed on at least a portion of the inner surface of the shell, the thermal conductivity of the heat-conducting insulating layer is 0.03W / mK-10W / mK, and the resistance of the heat-conducting insulating layer under a high voltage of 1000V is 100MΩ-100GΩ.

15. The method according to claim 14, characterized in that The method comprises: mixing 1 to 50 parts by weight of a thermally conductive filler, 50 to 95 parts by weight of a prepolymer and a solvent into a slurry, and forming the slurry on at least a portion of the inner surface of the housing to form the thermally conductive insulating layer.

16. The method according to claim 15, characterized in that Also includes: At least one of a dispersant and a curing agent is added to the slurry to form the thermally conductive insulating layer.

17. The method according to any one of claims 14 to 16, characterized in that: The method further comprises: cleaning and activating the housing before forming the thermally conductive insulating layer.

18. A battery, characterized in that: A shell comprising any one of claims 1-13 or a shell prepared by the method according to any one of claims 14-17.

19. The battery according to claim 18, characterized in that The shell comprises a bottom wall and a side wall, the side wall is connected to the edge of the bottom wall, the bottom wall and the side wall form a receiving cavity with an opening, the battery further comprises a positive electrode sheet, a negative electrode sheet and a separator, the positive electrode sheet, the negative electrode sheet and the separator are located in the receiving cavity, the positive electrode sheet comprises a positive electrode collector, the negative electrode sheet comprises a negative electrode collector, the positive projection of the separator on the side wall is located within the range of the positive projection of the negative electrode collector on the side wall and does not overlap, or the positive projection of the separator on the side wall is located within the range of the positive projection of the positive electrode collector on the side wall and does not overlap; The inner surface of the bottom wall is provided with the thermally conductive insulating layer, and the thermally conductive insulating layer is in contact with the negative electrode current collector or the positive electrode current collector.

20. The battery according to claim 19, characterized in that The orthographic projection of the separator on the side wall is located within the range of the orthographic projection of the negative electrode current collector on the side wall and does not overlap.

21. The battery according to claim 20, characterized in that The negative electrode current collector includes a first region and a second region, wherein the orthographic projection of the first region on the side wall coincides with the orthographic projection of the separator on the side wall, and the orthographic projection of the second region on the side wall is within the orthographic projection range of the thermally conductive insulating layer on the side wall.

22. The battery according to claim 21, characterized in that Along the extension direction of the negative electrode current collector, the length of the second region is D, and satisfies 1 mm≤D≤5 mm.

23. The battery according to any one of claims 20 to 22, characterized in that: An end of the orthographic projection of the heat-conducting insulating layer on the side wall close to the opening of the accommodating cavity coincides with an end of the orthographic projection of the diaphragm on the side wall away from the opening of the accommodating cavity.

24. The battery according to claim 23, characterized in that Along the extension direction of the negative electrode current collector, the height of the thermally conductive insulating layer on the side wall is H, H≥5mm, optionally, 1cm≤H≤3cm.

25. The battery according to any one of claims 20 to 24, characterized in that: The battery comprises: a top cover assembly, which is suitable for closing the opening of the accommodating cavity; the side walls are provided with the thermally conductive insulating layer, and an end of the thermally conductive insulating layer close to the top cover assembly is spaced apart from an end of the top cover assembly close to the shell.

26. The battery according to claim 25, characterized in that The distance between one end of the heat-conducting insulation layer close to the top cover assembly and one end of the top cover assembly close to the shell is L, and 2mm≤L≤5mm.

27. An electrical equipment, characterized in that: A battery comprising any one of claims 18 to 26.

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