Battery case, method for manufacturing the same, battery cell, battery device, and electric device

Abstract

The application discloses a battery shell and a manufacturing method thereof, a battery monomer, a battery device and a power utilization device. The battery shell comprises a shell body and an insulating coating. The insulating coating is arranged on the outer surface of the shell body. The insulating coating comprises an insulating coating arranged on the outer surface of the shell body. The voltage resistance U of the insulating coating, the thickness T0 of the insulating coating and the tensile strength A of the insulating coating satisfy the formula A(U-T0a)=T0b, wherein a is an insulating field intensity coefficient, a=0.2-50 V / μm, and b is a tensile strength correction coefficient of the insulating coating, b=30-90 VMPa / μm. According to the battery shell, the insulating protection performance of the insulating coating can be ensured, the safety performance of the battery shell can be improved, and a long-term safe operation mechanism of the battery can be established.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery casing and its manufacturing method, a battery cell, a battery device, and an electrical device. Background Technology

[0002] With the continuous development of the new energy industry, the application fields of batteries are also increasing. To prevent short circuits during the use of multiple batteries, insulation structures are typically installed on the battery casing. However, the insulation structures in these technologies have a high risk of failure, directly affecting the safety of battery use. Summary of the Invention

[0003] The first aspect of this application proposes a battery casing that has the advantage of high safety performance.

[0004] A battery casing according to a first aspect embodiment of this application includes: a casing body; and an insulating coating disposed on the outer surface of the casing body, wherein the withstand voltage U of the insulating coating, the thickness T0 of the insulating coating, and the tensile strength A of the insulating coating satisfy: A(U-T0) a) = T0 b, where: a is the insulation field strength coefficient, a = 0.2~50V / μm, and b is the tensile strength correction coefficient of the insulating coating, b = 30~90V. MPa / μm.

[0005] According to the battery casing of the first aspect of this application, the relationship between the voltage resistance U, thickness T0, and tensile strength A is satisfied by A(U-T0). a) = T0 b. In the preparation process of the insulating coating, based on the above relationship, by adjusting the values ​​of tensile strength and thickness, the withstand voltage can meet the design requirements of the insulating coating, so as to ensure the insulating protection performance of the insulating coating, thereby improving the safety performance of the battery casing and helping to establish a long-term safe operation mechanism for the battery.

[0006] In some embodiments of this application, the insulation field strength coefficient a = 0.3~25V / μm; and / or, the withstand voltage U of the insulating coating satisfies: 1000V≤U≤6000V; and / or, the thickness T0 of the insulating coating satisfies: 50μm≤T0≤5000μm; and / or, the tensile strength A of the insulating coating satisfies: A≥1MPa; and / or, the tensile strength A of the insulating coating satisfies: A≤20MPa.

[0007] In some embodiments of this application, the withstand voltage U of the insulating coating satisfies: 1250V≤U≤3000V; and / or, the thickness T0 of the insulating coating satisfies: 75μm≤T0≤2500μm; and / or, the tensile strength A of the insulating coating satisfies: A≥1.5MPa; and / or, the tensile strength A of the insulating coating satisfies: A≤10MPa.

[0008] In some embodiments of this application, the maximum thickness of the insulating coating is T01, the minimum thickness of the insulating coating is T02, and T01 and T02 satisfy: 0 < T01 - T02 ≤ 5000 μm; and / or; the thickness of the shell body is t0, which satisfies: 100 μm ≤ t0 ≤ 800 μm.

[0009] In some embodiments of this application, T01 and T02 satisfy: 0 < T01 - T02 ≤ 2500 μm; and / or; the thickness t0 of the shell body satisfies: 125 μm ≤ t0 ≤ 400 μm.

[0010] In some embodiments of this application, the thickness T0 of the insulating coating, the coverage area S of the insulating coating on the outer surface of the shell body, the resistivity ρ of the insulating coating, and the insulation resistance R of the insulating coating satisfy: T0 ≥ (R S) / ρ, where S, R, and ρ are only numerical values, T0 is in micrometers, R is in ohms, S is in square micrometers, and ρ is in ohms. centimeter.

[0011] In some embodiments of this application, the shell body includes a first sidewall, a second sidewall, and a connecting portion. The first sidewall and the second sidewall are arranged at an angle. The connecting portion connects the first sidewall and the second sidewall. The insulating coating includes a first insulating portion, a second insulating portion, and a third insulating portion. The first insulating portion is disposed on the first sidewall, the second insulating portion is disposed on the second sidewall, and the third insulating portion is disposed on the connecting portion and connects the first insulating portion and the second insulating portion. The thickness of the third insulating portion is greater than the thickness of the first insulating portion and / or the thickness of the third insulating portion is greater than the thickness of the second insulating portion.

[0012] In some embodiments of this application, the thickness T1 of the first insulating portion satisfies: 50μm≤T1≤200μm; and / or, the thickness T2 of the second insulating portion satisfies: 50μm≤T2≤200μm; and / or, the thickness T3 of the third insulating portion satisfies: 80μm≤T3≤450μm.

[0013] In some embodiments of this application, the thickness T1 of the first insulating portion satisfies: 75μm≤T1≤100μm; and / or, the thickness T2 of the second insulating portion satisfies: 75μm≤T2≤100μm; and / or, the thickness T3 of the third insulating portion satisfies: 100μm≤T3≤225μm.

[0014] In some embodiments of this application, the connecting part is arc-shaped, and the fillet radius r of the connecting part and the thickness T3 of the third insulating part satisfy: T3=C / r, where C is the coupling coefficient between the fillet radius r of the connecting part and the thickness T3 of the third insulating part, and the range of C is 10000~2500000. The units of T3 and r are micrometers.

[0015] In some embodiments of this application, the third insulating portion includes an underlayer coating that connects the first insulating portion and the second insulating portion. The first insulating portion, the second insulating portion, and the underlayer coating all include an attachment layer and an outer insulating layer. In any one of the first insulating portion, the second insulating portion, and the underlayer coating, the attachment layer is located between the shell body and the outer insulating layer.

[0016] In some embodiments of this application, the thickness of the attachment layer is t1, and the thickness of the outer insulation layer is t2; wherein t1 and t2 satisfy: 10μm≤|t2—t1|≤150μm; and / or, the thickness of the shell body is t0, and t0, t1 and t2 satisfy: 0.0125≤|t2—t1| / t0≤1.5.

[0017] In some embodiments of this application, t1 and t2 satisfy: 15μm≤|t2—t1|≤75μm; and / or, the thickness of the shell body is t0, and t0, t1 and t2 satisfy: 0.015≤|t2—t1| / t0≤0.75.

[0018] In some embodiments of this application, the third insulating portion further includes an insulating reinforcing layer disposed on the side of the bottom coating away from the shell body and covering at least a portion of the connecting portion.

[0019] In some embodiments of this application, the insulating reinforcement layer is an adhesive layer; and / or, the insulating reinforcement layer and the underlying coating are an integral structure.

[0020] In some embodiments of this application, the insulating reinforcement layer at least covers a portion of the first insulating portion; and / or, the insulating reinforcement layer at least covers a portion of the second insulating portion; and / or, the first insulating portion, the second insulating portion, and the bottom coating are integrally coated on the outer surface of the shell body.

[0021] In some embodiments of this application, the shell body is cylindrical, the outer peripheral wall of the shell body forms the second sidewall, a limiting groove is formed on the outer peripheral surface of the second sidewall, the insulating coating further includes an insulating filling portion, the insulating filling portion is disposed in the limiting groove, and the second insulating portion is located on the outer peripheral side of the insulating filling portion and covers the insulating filling portion.

[0022] In some embodiments of this application, the insulating filler is an adhesive layer; and / or, the insulating filler and the second insulating part are an integral structure; and / or, the thickness T2 of the second insulating part and the thickness T4 of the insulating filler satisfy: 300μm≤T2+T4≤4000μm; and / or, along the radial direction of the shell body, the depth of the insulating filler is the same as the depth of the limiting groove, and the outer peripheral surface of the insulating filler is flush with the outer peripheral surface of the shell body.

[0023] In some embodiments of this application, the thickness T2 of the second insulating portion and the thickness T4 of the insulating filling portion satisfy: 400μm≤T2+T4≤2000μm.

[0024] The second aspect of this application discloses a method for manufacturing a battery casing.

[0025] A method for manufacturing a battery casing according to a second aspect of this application includes: providing a casing body; and preparing an insulating coating on the outer surface of the casing body, including: selecting the thickness T0 and tensile strength A of the insulating coating according to the required insulation withstand voltage U of the battery casing, wherein the withstand voltage U, the thickness T0, and the tensile strength A of the insulating coating satisfy: A(U-T0) a) = T0 b, where a is the insulation field strength coefficient, a = 0.2~50V / μm; b is the tensile strength correction coefficient, b = 30~90V·MPa / μm, and the unit of U is V.

[0026] According to the battery casing manufacturing method of the second aspect of this application, the relationship between the withstand voltage U, thickness T0, and tensile strength A is constructed to satisfy A(U-T0). a) = T0 b. In the preparation process of the insulating coating, based on the above relationship, by adjusting the values ​​of tensile strength and thickness, the withstand voltage can meet the design requirements of the insulating coating, so as to ensure the insulating protection performance of the insulating coating, thereby improving the safety performance of the battery casing and helping to establish a long-term safe operation mechanism for the battery.

[0027] The third aspect of this application proposes a battery cell.

[0028] A battery cell according to a third aspect of this application includes: a battery casing as described in the first aspect of the application; and an electrode assembly disposed within the battery casing.

[0029] According to the battery cell of the third aspect embodiment of this application, the relationship between the withstand voltage U, thickness T0 and tensile strength A is satisfied by A(U-T0). a) = T0 b. In the preparation process of the insulating coating, based on the above relationship, by adjusting the values ​​of tensile strength and thickness, the withstand voltage can meet the design requirements of the insulating coating, so as to ensure the insulating protection performance of the insulating coating, thereby improving the safety performance of the battery casing and helping to establish a long-term safe operation mechanism for the battery.

[0030] The fourth aspect of this application discloses a battery device.

[0031] A battery device according to a fourth aspect of this application includes: a housing; and a plurality of battery cells described in the third aspect of the present application, wherein the battery cells are disposed within the housing.

[0032] According to the battery device of the fourth aspect of this application, the relationship between the withstand voltage U, thickness T0, and tensile strength A is constructed to satisfy A(U-T0). a) = T0 b. In the preparation process of the insulating coating, based on the above relationship, by adjusting the values ​​of tensile strength and thickness, the withstand voltage can meet the design requirements of the insulating coating, so as to ensure the insulating protection performance of the insulating coating, thereby improving the safety performance of the battery casing and helping to establish a long-term safe operation mechanism for the battery.

[0033] The fifth aspect of this application discloses an electrical device.

[0034] The electrical device according to the fifth aspect of this application includes: the battery device of the fourth aspect of the present application.

[0035] According to the fifth aspect embodiment of the present application, the electrical device is constructed such that the relationship between the withstand voltage U, the thickness T0, and the tensile strength A satisfies A(U-T0). a) = T0 b. In the preparation process of the insulating coating, based on the above relationship, by adjusting the values ​​of tensile strength and thickness, the withstand voltage can meet the design requirements of the insulating coating, so as to ensure the insulating protection performance of the insulating coating, thereby improving the safety performance of the battery casing and helping to establish a long-term safe operation mechanism for the battery.

[0036] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of a battery casing according to an embodiment of this application; Figure 2 This is a cross-sectional view of the battery casing according to an embodiment of this application; Figure 3 yes Figure 2 Enlarged view of region A in the middle; Figure 4 yes Figure 2 Enlarged view of region B in the middle; Figure 5 This is a schematic diagram of the insulating coating and the casing body of the battery casing according to an embodiment of this application; Figure 6 This is a schematic diagram of a battery cell according to an embodiment of this application; Figure 7 This is a schematic diagram of a battery device according to an embodiment of this application.

[0038] Figure label: 1000, Battery assembly; 100, Battery cell; 200, Housing; 10, Battery casing; 1, Casing body; 11, First sidewall; 12, Second sidewall; 13, Connecting part; 14, Limiting groove; 2, Insulating coating; 20a, Adhesive layer; 20b, Outer insulating layer; 21, First insulating part; 22, Second insulating part; 23, Third insulating part; 231, Undercoating layer; 232, Insulating reinforcement layer; 24, Insulating filling part; 20, Terminal post. Detailed Implementation

[0039] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0040] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0041] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0042] In the description of this application, "multiple" means two or more.

[0043] The battery casing 10 according to a first aspect embodiment of the present application is described below with reference to the accompanying drawings.

[0044] like Figures 1 to 4 As shown, the battery casing 10 according to the first aspect of the present application includes: a casing body 1 and an insulating coating 2. The insulating coating 2 is disposed on the outer surface of the casing body 1. The withstand voltage U of the insulating coating 2, the thickness T0 of the insulating coating 2, and the tensile strength A of the insulating coating 2 satisfy: A(U-T0) a) = T0 Where: a is the insulation field strength coefficient, that is, a is the dielectric strength of the insulating coating 2, a = 0.2~50V / μm; b is the tensile strength correction coefficient of the insulating coating 2, b = 30~90V. MPa / μm. Where U is in V (volts), the greater the tensile strength A of the insulating coating 2, the stronger the long-term adhesion of the insulating coating 2 to the shell body 1.

[0045] In formula A(U-T0) a) = T0 b in: T0 a: Thickness Dielectric strength is understood as the theoretical breakdown voltage, but the actual breakdown voltage (withstand voltage) deviates from the theoretical breakdown voltage due to internal defects (bubbles, impurities, microcracks), etc. This deviation is achieved through (U-T0). a) indicates.

[0046] A represents the tensile strength, reflecting the cohesive force of the insulating coating 2 material. High tensile strength indicates strong cohesive force, making it less prone to cracking, powdering, and peeling during repeated temperature changes in the battery. Therefore, the tensile strength of the insulating coating 2 affects its adhesion and voltage resistance to the casing 1 during long-term battery use; through A(U-T0) a) It can comprehensively reflect the long-term electrical resistance of the insulating coating 2 under repeated temperature changes of the battery.

[0047] b is the tensile strength correction factor for insulating coating 2. Considering the thickness tolerance fluctuations and actual effects of insulating coating 2 during preparation, the influence of thickness is identified by increasing the factor, i.e., T0 b can effectively correct the influence of thickness tolerance fluctuations on tensile strength during the preparation of insulating coating 2.

[0048] Therefore, by constructing a relationship between voltage withstand voltage U, thickness T0, and tensile strength A, the relationship A(U-T0) can be satisfied. a) = T0 b can accurately reflect the relationship between the tensile strength, withstand voltage, and thickness of the insulating coating 2. Therefore, during the preparation of the insulating coating 2, the tensile strength and thickness values ​​can be adjusted according to the above relationship to ensure that the withstand voltage meets the design requirements of the insulating coating 2, thereby improving the insulation protection performance of the insulating coating 2. This can improve the safety performance of the battery casing and help establish a long-term safe operation mechanism for the battery.

[0049] It should be noted that when the insulating coating 2 has a multilayer structure, the dielectric strength 'a' of each layer satisfies a = 0.2~50V / μm, while the withstand voltage U and tensile strength A represent the overall performance of the insulating coating 2. Here, 'a' can be 0.2V / μm, 0.5V / μm, 1V / μm, 3V / μm, 5V / μm, 10V / μm, 20V / μm, 30V / μm, 50V / μm, etc., and 'b' can be 30V / μm. MPa / μm, 40V MPa / μm, 50V MPa / μm, 60V MPa / μm, 70V MPa / μm, 80V MPa / μm, 90V MPa / μm, etc., are not specifically limited here.

[0050] According to the battery casing 10 of the first aspect of the present application, the relationship between the voltage withstand U, thickness T0 and tensile strength A is satisfied by constructing a structure that satisfies A(U-T0). a) = T0 b. In the preparation process of insulating coating 2, by adjusting the values ​​of tensile strength and thickness, based on the above relationship, the withstand voltage meets the design requirements of insulating coating 2, so as to ensure the insulation protection performance of insulating coating 2, thereby improving the safety performance of battery casing and helping to establish a long-term safe operation mechanism for battery.

[0051] The tensile strength A is primarily tested using a tensile test method, according to standards such as GB / T228.1-2021. An axial load is applied to the sample using a universal testing machine until fracture, and the strength is calculated using the maximum load and the original cross-sectional area. The withstand voltage U can be measured using GB / T1408.1-2016, "Electrical Strength Test Methods for Insulating Materials Part 1: Power Frequency Tests," which standardizes the power frequency withstand voltage test procedure for insulating materials. Thickness can be measured using methods such as eddy current thickness measurement and ultrasonic thickness measurement, referring to standard GB / T4957-2003.

[0052] In some embodiments of this application, the insulation field strength coefficient a = 0.3~25V / μm. Therefore, by increasing the insulation field strength coefficient, i.e., the lower limit of the dielectric strength, the voltage threshold for breakdown of the insulating coating 2 can be increased, thereby improving the insulation performance of the insulating coating 2. In addition, by controlling the upper limit of the insulation field strength coefficient, the material requirements for the insulating coating 2 can be reduced, thereby reducing the manufacturing cost of the insulating coating 2.

[0053] In some embodiments of this application, the withstand voltage U of the insulating coating 2 satisfies: 1000V ≤ U ≤ 6000V. Therefore, while satisfying the withstand voltage performance of the insulating coating 2, the risk of breakdown due to an excessively low withstand voltage can be avoided. Simultaneously, the problem of increased production costs due to the need for a thicker protective coating caused by an excessively high withstand voltage can be avoided. In other words, the manufacturing cost of the insulating coating 2 can be reduced while ensuring its withstand voltage performance. The withstand voltage of the insulating coating 2 can be 1000V, 2000V, 3000V, 4000V, 5000V, 6000V, etc.

[0054] In some embodiments of this application, the withstand voltage U of the insulating coating 2 satisfies: 1250V≤U≤3000V. Therefore, the lower limit of the withstand voltage of the insulating coating 2 can be increased to improve its insulation performance, and by lowering the upper limit of the withstand voltage, the performance requirements of the material used to prepare the insulating coating 2 can be reduced, thereby lowering the preparation cost of the insulating coating 2.

[0055] In some embodiments of this application, the thickness T0 of the insulating coating 2 satisfies: 50μm ≤ T0 ≤ 5000μm. If the insulating coating 2 is too thin, its withstand voltage is too low, making it susceptible to breakdown and puncture, thus increasing the risk of failure. Conversely, if the insulating coating 2 is too thick, it occupies more space in the thickness direction of the casing 1, resulting in an excessively large overall size of the battery casing 10, which is detrimental to controlling the size of the battery cell 100 and also increases production costs. Therefore, by controlling the thickness of the insulating coating 2 within the range of 50μm to 5000μm, the risk of insulation failure due to an excessively thin insulating coating 2 can be avoided, while the excessive size of the battery casing 10 and increased production costs due to an excessively thick insulating coating 2 can also be avoided. This allows for control of the size and production cost of the battery casing 10 while ensuring the insulating protective performance of the insulating coating 2. The thickness of the insulating coating 2 can be 50μm, 100μm, 200μm, 500μm, 1000μm, 2000μm, 3000μm, 4000μm, 5000μm, etc., and no specific limitation is made here.

[0056] In some embodiments of this application, the thickness T0 of the insulating coating 2 satisfies: 75μm≤T0≤2500μm. This increases the lower limit of the insulating coating 2's thickness, ensuring sufficient thickness to guarantee insulation performance. Furthermore, it allows for better control of the maximum thickness of the insulating coating 2, reducing its fabrication difficulty and decreasing the required materials, thus lowering its fabrication cost.

[0057] In some embodiments of this application, the tensile strength A of the insulating coating 2 satisfies: A ≥ 1 MPa. When the tensile strength of the insulating coating 2 is too low, the adhesion of the insulating coating 2 to the shell body 1 decreases, posing a risk of insulation failure due to the insulating coating 2 detaching. Therefore, by controlling the tensile strength of the insulating coating 2 to a range not lower than 1 MPa, the adhesion of the insulating coating 2 to the shell body 1 can be improved, ensuring a firm connection between the insulating coating 2 and the shell body 1, thereby enhancing the insulation protection performance of the insulating coating 2.

[0058] In some embodiments of this application, the tensile strength A of the insulating coating 2 satisfies: A≥1.5MPa. This increases the tensile strength of the insulating coating 2, reducing the risk of it detaching, and improves its adhesion to the shell body 1, thus ensuring its insulating and protective performance.

[0059] In some embodiments of this application, the tensile strength A of the insulating coating 2 satisfies: A ≤ 20 MPa. This reduces the process requirements for preparing the insulating coating 2, thus lowering the difficulty of its preparation. For example, the tensile strength of the insulating coating 2 can be 1 MPa, 2 MPa, 3 MPa, 5 MPa, 7 MPa, 9 MPa, 10 MPa, 12 MPa, 15 MPa, 18 MPa, 20 MPa, etc.

[0060] In some embodiments of this application, the tensile strength A of the insulating coating 2 satisfies: A≤10MPa. Therefore, by reducing the tensile strength requirement of the insulating coating 2, the process requirements for preparing the insulating coating 2 can be reduced, i.e., the difficulty of preparing the insulating coating 2 can be lowered.

[0061] In some embodiments of this application, the maximum thickness of the insulating coating 2 is T01, and the minimum thickness of the insulating coating 2 is T02, where T01 and T02 satisfy: 0 < T01 - T02 ≤ 5000 μm. It should be noted that the aforementioned range of T0 refers to the fact that thickness tests at any location of the insulating coating 2 all meet the above thickness range. That is, the maximum thickness difference between different locations of the insulating coating 2 is controlled within a range not exceeding 5000 μm. This avoids large surface differences on the outer surface of the insulating coating 2, thereby preventing the risk of localized breakage or even detachment of the insulating coating 2 due to excessive thickness differences, thus ensuring the reliability of the connection between the insulating coating 2 and the shell body 1. The maximum thickness difference between different locations of the insulating coating 2 can be 50 μm, 100 μm, 200 μm, 500 μm, 1000 μm, 2000 μm, 3000 μm, 4000 μm, 5000 μm, etc., and no specific limitation is made here.

[0062] In some embodiments, the first insulating portion 21 and the second insulating portion 22 have the same thickness. The minimum thickness of the insulating coating 2 is the thickness of the first insulating portion 21 and the second insulating portion 22, and the maximum thickness of the insulating coating 2 is the sum of the thicknesses of the insulating filler portion 24 and the second insulating portion 22.

[0063] In some embodiments of this application, the maximum thickness of the insulating coating 2 is T01, and the minimum thickness of the insulating coating 2 is T02, wherein T01 and T02 satisfy: 0 < T01 - T02 ≤ 2500 μm. This effectively reduces the maximum thickness difference between different locations of the insulating coating 2, thereby avoiding the risk of localized breakage or even detachment of the insulating coating 2 due to excessive thickness differences, thus ensuring the reliability of the connection between the insulating coating 2 and the shell body 1.

[0064] In some embodiments of this application, the thickness t0 of the shell body 1 satisfies: 100μm ≤ t0 ≤ 800μm. If the shell body 1 is too thin, its mechanical strength is insufficient, and its resistance to deformation and corrosion is poor; if the shell body 1 is too thick, its weight is excessive, its cost increases, and it is detrimental to heat dissipation. Therefore, by controlling the thickness of the shell body 1 within the range of 100μm to 800μm, the shell body 1 has a certain thickness, improving its mechanical strength, resistance to deformation, and corrosion resistance, while avoiding excessive thickness, thereby controlling the weight and production cost of the shell body 1 and improving its heat dissipation performance. The thickness of the shell body 1 can be 100μm, 150μm, 200μm, 250μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, etc., and no specific limitation is made here.

[0065] In some embodiments of this application, the thickness t0 of the shell body 1 satisfies: 125μm≤t0≤400μm. Therefore, by increasing the lower limit of the shell body 1's thickness, the mechanical strength, deformation resistance, and corrosion resistance of the shell body 1 can be improved; furthermore, the upper limit requirement for the shell body 1's thickness can be reduced, thereby controlling the weight and production cost of the shell body 1 and improving its heat dissipation performance.

[0066] In some embodiments of this application, the thickness T0 of the insulating coating 2, the coverage area S of the insulating coating 2 on the outer surface of the shell body 1, the resistivity ρ of the insulating coating 2, and the insulation resistance R of the insulating coating 2 satisfy: T0 ≥ (R S) / ρ, where S, R, and ρ are only numerical values, T0 is in micrometers, R is in ohms, S is in square micrometers, and ρ is in ohms. Centimeters. It should be noted that R is the minimum insulation resistance of the insulating coating 2 designed for the battery casing 10. For example, if the insulation resistance of the insulating coating 2 needs to be greater than or equal to 2MΩ, then R is 200000. In other words, the larger the coverage area of ​​the insulating coating 2 on the outer surface of the casing 1 and / or the smaller the resistivity of the insulating coating 2, the thicker the insulating coating 2 needs to be to ensure its insulating protective performance against the casing 1. Conversely, the smaller the coverage area of ​​the insulating coating 2 on the outer surface of the casing 1 and / or the larger the resistivity of the insulating coating 2, the thinner the insulating coating 2 needs to be to reduce its production cost. Therefore, the minimum thickness of the insulating coating 2 can be accurately calculated based on the coverage area S of the insulating coating 2 on the outer surface of the casing 1, the resistivity ρ of the insulating coating 2, and the insulation resistance R of the insulating coating 2, to ensure its insulating performance.

[0067] In some embodiments of this application, the shell body 1 includes a first sidewall 11, a second sidewall 12, and a connecting portion 13. The first sidewall 11 and the second sidewall 12 are arranged at an angle, and the connecting portion 13 connects the first sidewall 11 and the second sidewall 12. The insulating coating 2 includes a first insulating portion 21, a second insulating portion 22, and a third insulating portion 23. The first insulating portion 21 is disposed on the first sidewall 11, the second insulating portion 22 is disposed on the second sidewall 12, and the third insulating portion 23 is disposed on the connecting portion 13 and connects the first insulating portion 21 and the second insulating portion 22. The thickness of the third insulating portion 23 is greater than the thickness of the first insulating portion 21 and / or the thickness of the third insulating portion 23 is greater than the thickness of the second insulating portion 22.

[0068] It should be noted that in related technologies, during the coating process of the insulating coating, due to the influence of the shape of the outer surface of the connecting part, the third insulating part is prone to gaps (i.e., exposed outer surface of the shell body), which may lead to insulation failure. In other words, the thickness of the portion of the insulating coating 2 located at the connecting part 13 is greater than the thickness of the portion of the insulating coating 2 located on the first sidewall 11 and / or greater than the thickness of the portion of the insulating coating 2 located on the second sidewall 12. The greater thickness can improve the insulation protection effect of the third insulating part 23 at the connecting part 13, thereby effectively avoiding the risk of insulation failure at the connecting part 13 and improving the insulation protection performance of the insulating coating 2.

[0069] In some embodiments of this application, the thickness of the first insulating portion 21 is T1, the thickness of the second insulating portion 22 is T2, and the thickness of the third insulating portion 23 is T3, wherein 2≤T3 / T1≤10; and / or, 2≤T3 / T2≤10; and / or, 30μm≤T3-T1≤300μm; and / or, 30μm≤T3-T2≤300μm. This avoids the risk of breakage or even detachment at the connection between the third insulating portion 23 and the first insulating portion 21 and the second insulating portion 22 due to excessive thickness differences. Simultaneously, it avoids the risk that insufficient thickness of the third insulating portion 23 will affect the insulation protection effect on the connecting portion 13, thereby improving the insulation protection performance of the third insulating portion 23.

[0070] In some embodiments of this application, the thickness T1 of the first insulating portion 21 satisfies: 50μm ≤ T1 ≤ 200μm. If the thickness of the first insulating portion 21 is too thin, its voltage withstand capability is too low, making it susceptible to breakdown and puncture, thus increasing the risk of failure. Conversely, if the thickness of the first insulating portion 21 is too thick, the space occupied in the thickness direction of the casing body 1 increases, resulting in an excessively large overall size of the battery casing 10, which is detrimental to controlling the size of the battery casing 10 and also increases production costs. Therefore, by controlling the thickness of the first insulating portion 21 within the range of 50μm to 200μm, the risk of insulation failure due to an excessively thin first insulating portion 21 can be avoided, while the excessive size of the battery casing 10 and increased production costs due to an excessively thick first insulating portion 21 can be avoided. This allows for control of the size and production cost of the battery casing 10 while ensuring the insulation protection performance of the first insulating portion 21. The thickness of the first insulating part 21 can be 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 120μm, 150μm, 180μm, 200μm, etc., and no specific limitation is made here.

[0071] In some embodiments of this application, the thickness T1 of the first insulating portion 21 satisfies: 75μm≤T1≤100μm. Therefore, by increasing the lower limit of the thickness of the first insulating portion 21, the insulation performance of the first insulating portion 21 can be improved; furthermore, by reducing the upper limit of the thickness of the first insulating portion 21, while ensuring the insulation performance of the first insulating portion 21, the thickness of the first insulating portion 21 and the materials required for its fabrication can be effectively controlled, thereby reducing the fabrication difficulty and cost of the first insulating portion 21.

[0072] In some embodiments of this application, the thickness T2 of the second insulating portion 22 satisfies: 50μm ≤ T2 ≤ 200μm. If the thickness of the second insulating portion 22 is too thin, its voltage withstand capability is too low, making it susceptible to breakdown and puncture, thus increasing the risk of failure. Conversely, if the thickness of the second insulating portion 22 is too thick, the space occupied in the thickness direction of the casing body 1 increases, resulting in an excessively large overall size of the battery casing 10. This is detrimental to controlling the size of the battery cell 100 and also increases production costs. Therefore, by controlling the thickness of the second insulating portion 22 within the range of 50μm to 200μm, the risk of insulation failure due to an excessively thin second insulating portion 22 can be avoided. Simultaneously, the excessively large size of the battery casing 10 and increased production costs due to an excessively thick second insulating portion 22 can be avoided. Thus, while ensuring the insulation protection performance of the second insulating portion 22, the size and production cost of the battery casing 10 can be controlled. The thickness of the second insulating part 22 can be 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 120μm, 150μm, 180μm, 200μm, etc., and no specific limitation is made here.

[0073] In some embodiments of this application, the thickness T1 of the second insulating portion 22 satisfies: 75μm≤T2≤100μm. Therefore, by increasing the lower limit of the thickness of the second insulating portion 22, the insulation performance of the second insulating portion 22 can be improved; furthermore, by reducing the upper limit of the thickness of the second insulating portion 22, while ensuring the insulation performance of the second insulating portion 22, the thickness of the second insulating portion 22 and the materials required for its fabrication can be effectively controlled, thereby reducing the fabrication difficulty and cost of the second insulating portion 22.

[0074] In some embodiments of this application, the thickness T3 of the third insulating portion 23 satisfies: 80μm ≤ T3 ≤ 450μm. When the thickness of the third insulating portion 23 is too small, the voltage withstand capability of the portion of the insulating coating 2 located at the connection portion 13 is too low, making it susceptible to breakdown, puncture, or gaps, thus increasing the risk of insulation failure at the connection portion 13. Conversely, when the thickness of the third insulating portion 23 is too large, the space occupied in the thickness direction of the shell body 1 increases, resulting in an excessively large overall size of the battery shell 10, which is detrimental to controlling the size of the battery cell 100 and also increases production costs. Therefore, by controlling the thickness of the third insulating portion 23 within the range of 80μm to 450μm, the risk of insulation failure at the connection portion 13 can be reduced, while avoiding excessive thickness leading to an excessively large size of the battery shell 10 and increased production costs. This allows for control of the size and production cost of the battery shell 10 while ensuring the insulating protective performance of the insulating coating 2. The thickness of the third insulating part 23 can be 80μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, etc., and no specific limitation is made here.

[0075] In some embodiments of this application, the thickness T1 of the third insulating portion 23 satisfies: 100μm≤T3≤225μm. Therefore, by increasing the lower limit of the thickness of the third insulating portion 23, the insulation performance of the third insulating portion 23 can be improved; furthermore, by reducing the upper limit of the thickness of the third insulating portion 23, while ensuring the insulation performance of the third insulating portion 23, the thickness of the third insulating portion 23 and the materials required for its fabrication can be effectively controlled, thereby reducing the fabrication difficulty and cost of the third insulating portion 23.

[0076] In some embodiments of this application, the connecting portion 13 is arc-shaped. The radius r of the fillet of the connecting portion 13 and the thickness T3 of the third insulating portion 23 satisfy: T3 = C / r, where C is the coupling coefficient between the radius r of the fillet of the connecting portion 13 and the thickness T3 of the third insulating portion 23, and C ranges from 10,000 to 2,500,000. The units of T3 and r are micrometers. The range of r is 100 to 5,000 μm. That is, the smaller the radius of the fillet of the connecting portion 13, the larger the thickness of the third insulating portion 23; the larger the radius of the fillet of the connecting portion 13, the smaller the thickness of the third insulating portion 23. The smaller the radius of the fillet of the connecting portion 13, the greater the curvature of the connecting portion 13, i.e., the more curved the connecting portion 13; conversely, the larger the radius of the fillet of the connecting portion 13, the smaller the curvature of the connecting portion 13, i.e., the straighter the connecting portion 13. In other words, the greater the curvature of the connecting part 13, the greater the thickness of the third insulating part 23, ensuring that the third insulating part 23 can completely cover the connecting part 13, so as to avoid the risk of insulation failure caused by the connection part 13 being left blank (i.e. the outer surface of the shell body 1 being exposed), thereby improving the insulation protection performance of the insulating coating 2 at the connecting part 13, and thus improving the safety performance of the battery shell 10.

[0077] By controlling the coupling coefficient C within the range of 10,000 to 2,500,000, two advantages can be achieved: firstly, an excessively thin third insulating part 23 due to a too-small coupling coefficient can be avoided, which would negatively impact insulation performance; secondly, an excessively thick third insulating part 23 due to a too-large coupling coefficient can be avoided, which would increase the size and production cost of the battery casing 10. In other words, the size and production cost of the battery casing 10 can be controlled while ensuring the insulation performance of the third insulating part 23. For example, the coupling coefficient C can be 10,000, 20,000, 50,000, 100,000, 200,000, 500,000, 1000,000, 1,500,000, 2,000,000, 2,500,000, etc., without specific limitations.

[0078] In some embodiments of this application, such as Figure 5As shown, the third insulating part 23 includes a bottom coating 231, which connects the first insulating part 21 and the second insulating part 22. The first insulating part 21, the second insulating part 22, and the bottom coating 231 each include an adhesion layer 20a and an outer insulating layer 20b. In any one of the first insulating part 21, the second insulating part 22, and the bottom coating 231, the adhesion layer 20a is located between the shell body 1 and the outer insulating layer 20b. That is, the outer insulating layer 20b of the first insulating part 21, the second insulating part 22, and the bottom coating 231 are respectively attached to the outer surface of the corresponding adhesion layer 20a and connected to the shell body 1 through the corresponding adhesion layer 20a. In other words, the insulating coating 2 is attached to the shell body 1 through the adhesion layer 20a. The adhesion layer 20a effectively enhances the adhesion of the insulating coating 2 to the shell body 1, preventing the insulating coating 2 from falling off the shell body 1, thereby ensuring the insulating protective effect of the insulating coating 2 on the shell body 1.

[0079] In some embodiments, the adhesion layer 20a may be made of a flexible material with high adhesion and high insulation, such as polyurethane, methyl acrylate, ethyl acrylate, and butyl acrylate, which can improve the adhesion of the insulating coating 2 to the surface of the shell body 1. The outer insulation layer 20b may be made of a weather-resistant material, such as epoxy resin and acrylate, which can improve the insulation effect and service life of the insulating coating 2.

[0080] In some embodiments of this application, the thickness of the adhesion layer 20a is t1, and the thickness of the outer insulating layer 20b is t2; wherein t1 and t2 satisfy: 10μm≤|t2—t1|≤150μm. It should be noted that the thicknesses of the adhesion layer 20a and the outer insulating layer 20b of the first insulating portion 21, the second insulating portion 22, and the bottom coating 231 all satisfy the above relationship.

[0081] In other words, the thickness difference between the adhesion layer 20a and the outer insulating layer 20b is controlled within the range of 10μm to 150μm. Taking a fixed thickness for the adhesion layer 20a and an outer insulating layer 20b thickness greater than that for the adhesion layer 20a as an example, if the thickness difference between the adhesion layer 20a and the outer insulating layer 20b is too large (i.e., the outer insulating layer 20b is too thick), it may lead to stress concentration at the interface, reducing the bonding force between the adhesion layer 20a and the outer insulating layer 20b, and increasing the risk of peeling off the outer insulating layer 20b. Conversely, if the thickness difference between the adhesion layer 20a and the outer insulating layer 20b is too small (i.e., the outer insulating layer 20b is too thin), it will result in reduced insulation performance of the outer insulating layer 20b. Therefore, by controlling the thickness difference between the adhesion layer 20a and the outer insulating layer 20b within the range of 10μm to 150μm, the bonding force between the adhesion layer 20a and the outer insulating layer 20b can be guaranteed, as well as the insulation performance of the outer insulating layer 20b. The thickness difference between the attachment layer 20a and the outer insulating layer 20b can be 10μm, 20μm, 30μm, 50μm, 70μm, 90μm, 100μm, 120μm, 150μm, etc., and no specific limitation is made here.

[0082] In some embodiments of this application, t1 and t2 satisfy: 15μm ≤ |t2—t1| ≤ 75μm. This reduces the thickness difference between the adhesion layer 20a and the outer insulating layer 20b, thereby mitigating process defects caused by an excessive thickness difference between the two layers and improving the yield of the battery casing 10.

[0083] In some embodiments of this application, the thickness of the shell body 1 is t0, and t0, t1, and t2 satisfy: 0.0125 ≤ |t2—t1| / t0 ≤ 1.5. Since different shell bodies 1 have different wall thicknesses, rigidities, and deformation ranges, by designing the ratio between the thickness difference of the attachment layer 20a and the outer insulating layer 20b and the thickness of the shell body 1, the deformation stress of the shell body 1 can be adapted to while also considering the safety margin of the insulating coating 2 to prevent damage due to stress, thus ensuring the insulation performance of the insulating coating 2. For example, |t2—t1| / t0 can be 0.0125, 0.025, 0.05, 0.1, 0.2, 0.3, 0.5, 0.7, 0.9, 1.0, 1.2, 1.4, 1.5, etc.

[0084] In some embodiments of this application, t0, t1, and t2 satisfy: 0.015 ≤ |t2—t1| / t0 ≤ 0.75. Therefore, while adapting to the deformation stress of the shell body 1, it also takes into account the safety margin of the insulating coating 2 in case of stress damage, thus ensuring the insulation performance of the insulating coating 2.

[0085] In some embodiments of this application, the third insulating portion 23 further includes an insulating reinforcing layer 232, which is disposed on the side of the bottom coating 231 away from the shell body 1 and covers at least a portion of the connecting portion 13. Thus, by providing the insulating reinforcing layer 232 on the outer side of the bottom coating 231, i.e., the side of the bottom coating 231 away from the shell body 1, the insulating reinforcing layer 232 can cover areas on the bottom coating 231 that are blank, have uneven thickness, or poor adhesion. In other words, the insulating reinforcing layer 232 can cover defective areas on the bottom coating 231 where there is a risk of insulation failure. Therefore, the bottom coating 231 and the insulating reinforcing layer 232 jointly provide insulating protection for the connecting portion 13, thereby improving the insulating protection performance of the insulating coating 2 on the shell body 1, and consequently improving the safety performance of the battery casing 10.

[0086] It should be noted that in the battery casing 10 with rounded corners, because the sprayed material is not easily maintained at the rounded corners in a liquid state, the thickness of the adhesion layer 20a in the bottom coating 231 of the third insulating part 23 is less than the thickness of the adhesion layer 20a in the first insulating part 21 and the second insulating part 22. Similarly, the thickness of the outer insulating layer 20b in the bottom coating 231 of the third insulating part 23 is less than the thickness of the outer insulating layer 20b in the first insulating part 21 and the second insulating part 22. Therefore, by providing an insulating reinforcing layer 232 on the outside of the bottom coating 231, the rounded corners on the casing body 1 can be reinforced, preventing exposed white areas.

[0087] In some embodiments of this application, the insulating reinforcement layer 232 is a dispensing layer, that is, the insulating reinforcement layer 232 can be formed on the insulating coating layer 2 by dispensing process, which is convenient for local application.

[0088] In some embodiments of this application, the insulating reinforcing layer 232 and the underlying coating 231 are an integral structure. That is, after the insulating coating 2 is cured, the insulating reinforcing layer 232 and the underlying coating 231 are connected to form an integral structure. This ensures the stability of the connection between the insulating reinforcing layer 232 and the underlying coating 231 and improves the reliability of the overall structure of the insulating coating 2.

[0089] In some embodiments of this application, the insulating reinforcement layer 232 at least partially covers the first insulating portion 21. That is, while the insulating reinforcement layer 232 covers the outer surface of the underlying coating 231, a portion of the insulating reinforcement layer 232 extends to the first sidewall 11 to at least cover the connection point between the first insulating portion 21 and the underlying coating 231. Therefore, the coverage area of ​​the insulating reinforcement layer 232 on the insulating coating 2 can be significantly increased, thereby increasing the insulating protection area of ​​the insulating reinforcement layer 232 on the shell body 1. This avoids the risk of insulation failure at the connecting portion 13 and the connection point between the connecting portion 13 and the first sidewall 11, thus improving the insulating protection performance of the insulating coating 2.

[0090] In some embodiments of this application, the insulating reinforcement layer 232 at least partially covers the second insulating portion 22. That is, while the insulating reinforcement layer 232 covers the outer surface of the underlying coating 231, a portion of the insulating reinforcement layer 232 extends to the second sidewall 12 to at least cover the connection point between the second insulating portion 22 and the underlying coating 231. Therefore, the coverage area of ​​the insulating reinforcement layer 232 on the insulating coating 2 can be significantly increased, thereby increasing the insulating protection area of ​​the insulating reinforcement layer 232 on the shell body 1. This avoids the risk of insulation failure at the connecting portion 13 and the connection point between the connecting portion 13 and the second sidewall 12, thus improving the insulating protection performance of the insulating coating 2.

[0091] In some embodiments of this application, the first insulating portion 21, the second insulating portion 22, and the undercoat 231 are integrally coated on the outer surface of the shell body 1. That is, the first insulating portion 21, the second insulating portion 22, and the undercoat 231 can be formed simultaneously in a single process. For example, the coating can be simultaneously applied to the outer surfaces of the first sidewall 11, the connecting portion 13, and the second sidewall 12, and then cured to simultaneously form the first insulating portion 21, the second insulating portion 22, and the undercoat 231. This eliminates the need for sequential production of the first insulating portion 21, the second insulating portion 22, and the undercoat 231, thus significantly reducing the production steps of the insulating coating 2 and improving the efficiency of coating the insulating coating 2 on the outer surface of the shell body 1. Furthermore, the connection strength between the undercoat 231 and the first insulating portion 21 and the second insulating portion 22 can be guaranteed, thereby reducing the risk of the undercoat 231 detaching and ensuring the insulating effect of the undercoat 231 at the connecting portion 13.

[0092] It should be noted that the coatings of the first insulating part 21, the second insulating part 22 and the bottom coating 231 can be sprayed on the outer surface of the shell body 1, and the coatings of the first insulating part 21, the second insulating part 22 and the bottom coating 231 can also be printed on the outer surface of the shell body 1. Here, there are no specific restrictions on the way the first insulating part 21, the second insulating part 22 and the bottom coating 231 are coated on the outer surface of the shell body 1.

[0093] In some embodiments of this application, such as Figure 4As shown, the shell body 1 is cylindrical, and the outer peripheral wall of the shell body 1 forms a second side wall 12. A limiting groove 14 is formed on the outer peripheral surface of the second side wall 12. The insulating coating 2 also includes an insulating filling part 24, which is disposed in the limiting groove 14. The second insulating part 22 is located on the outer peripheral side of the insulating filling part 24 and covers the insulating filling part 24. That is, the insulating filling part 24 is located inside the part of the second insulating part 22 that is opposite to the limiting groove 14. The insulating filling part 24 can fill at least part of the space of the limiting groove 14. The insulating filling part 24 can support the part of the second insulating part 22 that is opposite to the limiting groove 14 and the inner bottom wall of the limiting groove 14, thereby reducing the deformation of the part of the second insulating part 22 that is opposite to the limiting groove 14 toward the limiting groove 14, thereby improving the insulating protection performance of the insulating coating 2 at the limiting groove 14.

[0094] The limiting groove 14 can be an annular shape extending circumferentially along the shell body 1, or the limiting groove 14 can be an arc shape extending circumferentially along the shell body 1 and have multiple grooves arranged at intervals along the circumferential direction of the shell body 1. No specific restrictions are made here.

[0095] In some embodiments of this application, the insulating filler 24 is a dispensing layer. That is, the insulating filler 24 can be formed in the limiting groove 14 by a dispensing process, which facilitates local application.

[0096] In some embodiments of this application, the insulating filler portion 24 and the second insulating portion 22 are integrally formed. That is, after the insulating coating 2 is cured, the insulating filler portion 24 and the second insulating portion 22 are connected to form an integral structure. This ensures the stability of the connection between the insulating filler portion 24 and the second insulating portion 22 and improves the reliability of the overall structure of the insulating coating 2.

[0097] In some embodiments, the insulating reinforcing layer 232 is made of the same material as the insulating filler 24 and the outer insulating layer 20b. This improves the adhesion of the insulating reinforcing layer 232 to the outer insulating layer 20b and reduces the variety of materials required to prepare the insulating coating 2, thereby simplifying material management.

[0098] In some embodiments, the insulating reinforcing layer 232 and the insulating filler 24 are made of different materials than the outer insulating layer 20b. That is, the insulating reinforcing layer 232 and the insulating filler 24 can be made of different materials than the outer insulating layer 20b, as long as the insulating performance and adhesion of the insulating reinforcing layer 232 and the insulating filler 24 are guaranteed. For example, resins, etc., are used. There are no specific limitations on the materials of the insulating reinforcing layer 232 and the insulating filler 24.

[0099] In some embodiments of this application, the thickness T2 of the second insulating portion 22 and the thickness T4 of the insulating filling portion 24 satisfy: 300μm≤T2+T4≤4000μm; wherein, when the sum of the thicknesses of the second insulating portion 22 and the insulating filling portion 24 is too small, the voltage withstand performance of the portion of the insulating coating 2 located at the connection portion 13 is too low and easily broken down and punctured, which increases the risk of insulation failure at the limiting groove 14; conversely, when the sum of the thicknesses of the second insulating portion 22 and the insulating filling portion 24 is too large, the space occupied in the thickness direction of the shell body 1 increases, resulting in an excessively large overall size of the battery shell 10, which is not conducive to controlling the size of the battery cell 100, and the production cost also increases accordingly. Therefore, by controlling the sum of the thicknesses of the second insulating portion 22 and the insulating filling portion 24 within the range of 1000μm to 4000μm, the risk of insulation failure at the limiting groove 14 can be reduced. Simultaneously, excessive thickness can be avoided, preventing the battery casing 10 from becoming too large and increasing production costs. Thus, while ensuring the insulating protective performance of the insulating coating 2, the size and production cost of the battery casing 10 can be controlled. The sum of the thicknesses of the second insulating portion 22 and the insulating filling portion 24 can be 300μm, 500μm, 1000μm, 1500μm, 2000μm, 2500μm, 3000μm, 3500μm, 4000μm, etc., without specific limitations.

[0100] In some embodiments of this application, the thickness T2 of the second insulating portion 22 and the thickness T4 of the insulating filling portion 24 satisfy: 400μm≤T2+T4≤2000μm. Therefore, by increasing the lower limit of the thickness of the portion of the insulating coating 2 opposite to the limiting groove 14, the insulating protection performance of the insulating coating 2 for the area of ​​the limiting groove 14 can be improved. Furthermore, by reducing the upper limit of the thickness of the portion of the insulating coating 2 opposite to the limiting groove 14, while ensuring the insulating protection performance of the insulating coating 2 for the area of ​​the limiting groove 14, the thickness of the insulating coating 2 and the materials required for its preparation can be effectively controlled, thereby reducing the difficulty and cost of preparing the insulating coating 2.

[0101] In some embodiments of this application, the depth of the insulating filling portion 24 along the radial direction of the shell body 1 is the same as the depth of the limiting groove 14, and the outer peripheral surface of the insulating filling portion 24 is flush with the outer peripheral surface of the shell body 1. That is, the insulating filling portion 24 can better fill the limiting groove 14 and avoid the insulating filling portion 24 occupying the space on the outer peripheral side of the shell body 1, thereby improving the supporting effect of the insulating filling portion 24 on the second insulating portion 22, that is, ensuring the straightness of the second insulating portion 22 along the axial direction of the shell body 1, and reducing the space occupied by the insulating coating 2 on the outer peripheral side of the shell body 1.

[0102] A method for manufacturing a battery casing 10 according to a second aspect of this application is described below with reference to the accompanying drawings.

[0103] A method for manufacturing a battery casing 10 according to a second aspect embodiment of this application includes: providing a casing body 1; and preparing an insulating coating 2 on the outer surface of the casing body 1, including: selecting the thickness T0 and tensile strength A of the insulating coating 2 according to the required insulation withstand voltage U of the battery casing 10, wherein the withstand voltage U, the thickness T0, and the tensile strength A of the insulating coating 2 satisfy: A(U-T0) a) = T0 b, where a is the insulation field strength coefficient, a = 0.2~50V / μm; b is the tensile strength correction coefficient, b = 30~90V·MPa / μm; the unit of U is V. It should be noted that the insulation field strength coefficient a and the tensile strength A can be achieved by selecting materials and additives that meet the design requirements, which will not be elaborated upon here.

[0104] According to the manufacturing method of the battery casing 10 of the second aspect embodiment of this application, the relationship between the withstand voltage U, the thickness T0 and the tensile strength A is constructed to satisfy A(U-T0). a) = T0 b. In the preparation process of insulating coating 2, by adjusting the values ​​of tensile strength and thickness, based on the above relationship, the withstand voltage meets the design requirements of insulating coating 2, so as to ensure the insulation protection performance of insulating coating 2, thereby improving the safety performance of battery casing and helping to establish a long-term safe operation mechanism for battery.

[0105] The following description, with reference to the accompanying drawings, describes a battery cell 100 according to a third aspect of this application.

[0106] like Figure 6 As shown, a battery cell 100 according to a third aspect embodiment of this application includes: a battery casing 10 and an electrode assembly, the electrode assembly being disposed within the battery casing 10. The battery casing 10 is provided with terminal posts 20.

[0107] According to the battery cell 100 of the third aspect embodiment of this application, the relationship between the withstand voltage U, thickness T0 and tensile strength A is constructed to satisfy A(U-T0). a) = T0 b. In the preparation process of insulating coating 2, by adjusting the values ​​of tensile strength and thickness, based on the above relationship, the withstand voltage meets the design requirements of insulating coating 2, so as to ensure the insulation protection performance of insulating coating 2, thereby improving the safety performance of battery casing and helping to establish a long-term safe operation mechanism for battery.

[0108] like Figure 7 As shown, a battery device 1000 according to a fourth aspect embodiment of this application includes: a housing 200 and a plurality of battery cells 100, wherein the battery cells 100 are disposed within the housing 200.

[0109] According to the battery device 1000 of the fourth aspect embodiment of this application, the relationship between the withstand voltage U, thickness T0 and tensile strength A is constructed to satisfy A(U-T0). a) = T0 b. In the preparation process of insulating coating 2, by adjusting the values ​​of tensile strength and thickness, based on the above relationship, the withstand voltage meets the design requirements of insulating coating 2, so as to ensure the insulation protection performance of insulating coating 2, thereby improving the safety performance of battery casing and helping to establish a long-term safe operation mechanism for battery.

[0110] An electrical device according to a fifth aspect of this application includes a battery device 1000.

[0111] According to the fifth aspect embodiment of the present application, the electrical device is constructed such that the relationship between the withstand voltage U, the thickness T0, and the tensile strength A satisfies A(U-T0). a) = T0 b. In the preparation process of insulating coating 2, by adjusting the values ​​of tensile strength and thickness, based on the above relationship, the withstand voltage meets the design requirements of insulating coating 2, so as to ensure the insulation protection performance of insulating coating 2, thereby improving the safety performance of battery casing and helping to establish a long-term safe operation mechanism for battery.

[0112] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0113] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery casing, characterized in that, include: Shell body; An insulating coating is provided on the outer surface of the shell body. The withstand voltage U of the insulating coating, the thickness T0 of the insulating coating, and the tensile strength A of the insulating coating satisfy: A(U-T0) a) = T0 Where: a is the insulation field strength coefficient, a = 0.2~50V / μm, and b is the tensile strength correction coefficient of the insulating coating, b = 30~90V. MPa / μm.

2. The battery casing according to claim 1, characterized in that, The insulation field strength coefficient a = 0.3~25V / μm; and / or, the withstand voltage U of the insulating coating satisfies: 1000V≤U≤6000V; and / or, the thickness T0 of the insulating coating satisfies: 50μm≤T0≤5000μm; and / or, the tensile strength A of the insulating coating satisfies: A≥1MPa; and / or, the tensile strength A of the insulating coating satisfies: A≤20MPa.

3. The battery casing according to claim 2, characterized in that, The withstand voltage U of the insulating coating satisfies: 1250V≤U≤3000V; and / or, the thickness T0 of the insulating coating satisfies: 75μm≤T0≤2500μm; and / or, the tensile strength A of the insulating coating satisfies: A≥1.5MPa; and / or, the tensile strength A of the insulating coating satisfies: A≤10MPa.

4. The battery casing according to claim 1, characterized in that, The maximum thickness of the insulating coating is T01, and the minimum thickness of the insulating coating is T02. T01 and T02 satisfy: 0 < T01 - T02 ≤ 5000 μm; and / or; the thickness of the shell body is t0, which satisfies: 100 μm ≤ t0 ≤ 800 μm.

5. The battery casing according to claim 4, characterized in that, T01 and T02 satisfy: 0 < T01 - T02 ≤ 2500 μm; and / or; the thickness of the shell body, t0, satisfies: 125 μm ≤ t0 ≤ 400 μm.

6. The battery casing according to claim 1, characterized in that, The thickness T0 of the insulating coating, the coverage area S of the insulating coating on the outer surface of the shell body, the resistivity ρ of the insulating coating, and the insulation resistance R of the insulating coating satisfy: T0 ≥ (R S) / ρ, where S, R, and ρ are only numerical values, T0 is in micrometers, R is in ohms, S is in square micrometers, and ρ is in ohms. centimeter.

7. The battery casing according to claim 1, characterized in that, The shell body includes a first sidewall, a second sidewall, and a connecting portion. The first sidewall and the second sidewall are arranged at an angle. The connecting portion connects the first sidewall and the second sidewall. The insulating coating includes a first insulating portion, a second insulating portion, and a third insulating portion. The first insulating portion is disposed on the first sidewall, the second insulating portion is disposed on the second sidewall, and the third insulating portion is disposed on the connecting portion and connects the first insulating portion and the second insulating portion. The thickness of the third insulating portion is greater than the thickness of the first insulating portion and / or the thickness of the third insulating portion is greater than the thickness of the second insulating portion.

8. The battery casing according to claim 7, characterized in that, The thickness T1 of the first insulating part satisfies: 50μm≤T1≤200μm; And / or, the thickness T2 of the second insulating portion satisfies: 50μm≤T2≤200μm; And / or, the thickness T3 of the third insulating portion satisfies: 80μm≤T3≤450μm.

9. The battery casing according to claim 8, characterized in that, The thickness T1 of the first insulating part satisfies: 75μm≤T1≤100μm; And / or, the thickness T2 of the second insulating portion satisfies: 75μm≤T2≤100μm; And / or, the thickness T3 of the third insulating part satisfies: 100μm≤T3≤225μm.

10. The battery casing according to claim 7, characterized in that, The connecting part is arc-shaped, and the radius r of the fillet of the connecting part and the thickness T3 of the third insulating part satisfy: T3=C / r, where C is the coupling coefficient between the radius r of the fillet of the connecting part and the thickness T3 of the third insulating part, and the range of C is 10000~2500000. The units of T3 and r are micrometers.

11. The battery casing according to claim 7, characterized in that, The third insulating portion includes a bottom coating that connects the first insulating portion and the second insulating portion. The first insulating portion, the second insulating portion, and the bottom coating each include an attachment layer and an outer insulating layer. In any one of the first insulating portion, the second insulating portion, and the bottom coating, the attachment layer is located between the shell body and the outer insulating layer.

12. The battery casing according to claim 11, characterized in that, The thickness of the adhesion layer is t1, and the thickness of the outer insulation layer is t2; Where t1 and t2 satisfy: 10μm≤|t2—t1|≤150μm; And / or, the thickness of the shell body is t0, and t0, t1 and t2 satisfy: 0.0125≤|t2—t1| / t0≤1.

5.

13. The battery casing according to claim 12, characterized in that, t1 and t2 satisfy: 15μm≤|t2—t1|≤75μm; And / or, the thickness of the shell body is t0, and t0, t1 and t2 satisfy: 0.015≤|t2—t1| / t0≤0.

75.

14. The battery casing according to claim 11, characterized in that, The third insulating portion further includes an insulating reinforcement layer, which is disposed on the side of the bottom coating away from the shell body and covers at least a portion of the connecting portion.

15. The battery casing according to claim 14, characterized in that, The insulating reinforcement layer is an adhesive layer; and / or, the insulating reinforcement layer and the underlying coating are an integral structure.

16. The battery casing according to claim 14, characterized in that, The insulating reinforcement layer at least covers a portion of the first insulating part; and / or, the insulating reinforcement layer at least covers a portion of the second insulating part; and / or, the first insulating part, the second insulating part, and the bottom coating are integrally coated on the outer surface of the shell body.

17. The battery casing according to claim 7, characterized in that, The shell body is cylindrical, and the outer peripheral wall of the shell body forms the second side wall. A limiting groove is formed on the outer peripheral surface of the second side wall. The insulating coating also includes an insulating filling part, which is disposed in the limiting groove. The second insulating part is located on the outer peripheral side of the insulating filling part and covers the insulating filling part.

18. The battery casing according to claim 17, characterized in that, The insulating filling part is an adhesive layer; And / or, the insulating filling portion and the second insulating portion are an integral structure; And / or, the thickness T2 of the second insulating portion and the thickness T4 of the insulating filling portion satisfy: 300μm≤T2+T4≤4000μm; And / or, along the radial direction of the shell body, the depth of the insulating filling portion is the same as the depth of the limiting groove, and the outer peripheral surface of the insulating filling portion is flush with the outer peripheral surface of the shell body.

19. The battery casing according to claim 18, characterized in that, The thickness T2 of the second insulating part and the thickness T4 of the insulating filling part satisfy: 400μm≤T2+T4≤2000μm.

20. A method for manufacturing a battery casing, characterized in that, include: Provide the shell body; An insulating coating is prepared on the outer surface of the casing body, comprising: selecting the thickness T0 and tensile strength A of the insulating coating according to the required insulation withstand voltage U of the battery casing, wherein the withstand voltage U, the thickness T0, and the tensile strength A of the insulating coating satisfy: A(U-T0) a) = T0 b, where a is the insulation field strength coefficient, a = 0.2~50V / μm; b is the tensile strength correction coefficient, b = 30~90V·MPa / μm, and the unit of U is V.

21. A single battery cell, characterized in that, include: Battery casing according to any one of claims 1-19; The electrode assembly is located inside the battery casing.

22. A battery device, characterized in that, include: Box; Multiple battery cells according to claim 21, wherein the battery cells are disposed within the housing.

23. An electrical appliance, characterized in that, include: The battery device according to claim 22.

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