Battery pack cover, battery pack, and vehicle

Abstract

The present disclosure discloses a battery pack cover, a battery pack, and a vehicle. The battery pack cover (100) includes a first substrate (10) having a thickness of a1 (mm) and a thermal conductivity of b1 (W / (m·K)), and a second substrate (20) located on one side of the first substrate (10), the second substrate (20) having a thickness of a2 (mm) and a thermal conductivity of b2 (W / (m·K)), where the first substrate (10) and the second substrate (20) satisfy the condition 6.67 < a1 / b1 + a2 / b2 < 100.04.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and benefit of Chinese Patent Application No. 202310123761.5.X, filed with the State Intellectual Property Office of China on February 2, 2023, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to the field of vehicles, and more particularly to a battery pack cover, a battery pack, and a vehicle. [Background technology]

[0003] In the field of power batteries, existing packaging structures still have problems such as large size, heavy weight, and inconvenience for high integration with vehicles.

[0004] Therefore, current battery pack covers, battery packs and vehicles still need improvement. Summary of the Invention

[0005] The present application aims to alleviate or solve, at least to some extent, at least one of the problems set forth above.

[0006] In one aspect of the present application, the present application provides a battery pack cover including a first substrate with a thickness of a1 (mm) and a thermal conductivity of b1 (W / (m·K)), and a second substrate located on one side of the first substrate, with a thickness of a2 (mm) and a thermal conductivity of b2 (W / (m·K)). The first substrate and the second substrate satisfy the condition of 6.67 < a1 / b1 + a2 / b2 < 100.04. Therefore, the battery pack cover has an excellent heat insulation effect and can be used as a sealing structure for the battery pack. Also, the battery pack cover has excellent support performance and may be used as a vehicle body floor structure, whereby the battery pack cover can be highly integrated with the vehicle body floor. This saves installation space, reduces the weight of the entire vehicle, and meets the safety requirements under extreme operating conditions.

[0007] In another aspect of the present application, the present application provides a battery pack including a battery, a tray, and the above-mentioned battery pack cover, wherein the battery pack cover and the tray are connected to form a housing cavity for housing the battery. Therefore, the battery pack has all the features and advantages of the above-mentioned battery pack cover. Details will not be described again here.

[0008] In yet another aspect of the present application, the present application provides a vehicle including a vehicle body floor, and the vehicle body floor includes the above-mentioned battery pack cover. Therefore, the vehicle has all the features and advantages of the above-mentioned battery pack cover. Details will not be described again here.

[0009] The above and / or additional aspects and advantages of the present application will become apparent and will be easily understood from the description of the embodiments with reference to the following drawings.

Brief Description of the Drawings

[0010] [Figure 1] It is a structural diagram of a vehicle body chassis assembly according to an embodiment of the present application. [Figure 2] 1 is a structural diagram of a battery pack cover according to an embodiment of the present application. [Figure 3] 1 is a structural diagram of a battery pack cover according to an embodiment of the present application. [Figure 4] 1 is a structural diagram of a battery pack cover according to an embodiment of the present application. [Figure 5] 1 is a structural diagram of a battery pack cover according to an embodiment of the present application. [Figure 6] 1 is a structural diagram of reinforcing fibers in a composite plate according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0011]

[0013] The embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, in which the same or similar reference numerals represent 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 are only used to explain the present application, and should not be construed as limiting the present application.

[0012] In one aspect, the present application proposes a battery pack cover 100 including a first substrate 10, the first substrate 10 having a thickness a1 (mm) and a thermal conductivity b1 (W / (m·K)), and a second substrate 20, the second substrate 20 being located on one side of the first substrate 10, the second substrate 20 having a thickness a2 (mm) and a thermal conductivity b2 (W / (m·K)). Through detailed theoretical analysis and experimental research, the inventors have found that the thermal resistance of the battery pack cover 100 is primarily limited by the thermal conductivity and thickness of the materials. The first substrate 10 and the second substrate 20 satisfy the condition 6.67≦a1 / b1+a2 / b2≦100.04. Within this formula, the battery pack cover 100 has good thermal insulation performance, and the battery pack can meet the condition that the time required for the battery pack to drop from 20°C to 0°C in a -10°C environment exceeds 15 hours. This allows the battery pack to balance thermal insulation performance and energy density, promoting full utilization of battery performance. The battery pack cover 100 has excellent thermal insulation properties and can be used as a sealing structure for the battery pack. In addition, the battery pack cover has excellent support properties and can be used as a vehicle floor structure, allowing the battery pack cover 100 to be highly integrated with the vehicle floor. This saves installation space, reduces the overall vehicle weight, and meets safety requirements under extreme operating conditions.

[0013] According to some embodiments of the present application, the thickness a1 of the first substrate 10 may be 0.4 mm to 2.5 mm. When the thickness of the first substrate 10 is 0.4 mm to 2.5 mm, the first substrate 10 has higher strength and better load-bearing support effect, occupies less space, and has less impact on the weight of the entire vehicle.

[0014] According to some embodiments of the present application, the thermal conductivity b1 of the first substrate 10 may be 40 W / (m·K) to 80 W / (m·K), which can improve the uniform thermal performance of the battery pack cover 100.

[0015] According to some embodiments of the present application, the first substrate 10 may be a metal plate, and the type of the metal plate is not particularly limited. Specifically, the metal plate may be a galvanized steel plate. In some embodiments, the density of the galvanized surface of the galvanized steel plate is 40 g / m or less. 2 ~80g / m 2The battery pack cover 100 may have a better load-bearing function through the metal plate construction. According to some embodiments of the present application, the second substrate 20 may be a composite plate. The composite plate may be a resin-based composite plate. The composite plate has a lower thermal conductivity and better thermal insulation performance than a metal plate. The composite plate also has electrical insulation properties and can effectively meet the high-voltage safety requirements of the battery pack cover 100. The composite plate includes a matrix resin and reinforcing fibers. The matrix resin of the composite plate may include at least one of epoxy resin, polyamide resin, polyurethane resin, polyimide resin, polysulfone resin, and phenolic resin. According to some other embodiments of the present application, the reinforcing fibers may be a fiber material having a melting point of 700°C or higher. Specifically, the reinforcing fibers may include at least one of glass fiber and ceramic fiber. See FIG. 6. Because the reinforcing fibers in the composite plate are arranged in a woven layup with excellent woven anisotropy, the reinforcing fibers in the composite plate may be laminated in any manner, including, but not limited to, the manner shown in FIG. 6. Glass fiber is used as an example. The orientation of adjacent glass fibers in the same fiber layer may be perpendicular to each other, which can effectively improve the support performance and tensile strength of the composite plate. The included angle between the orientation of glass fibers in adjacent fiber layers laminated in the first direction is not particularly limited. Those skilled in the art may adjust the included angle between the orientation of glass fibers in adjacent fiber layers based on actual conditions.

[0016] According to some embodiments of the present application, the thickness of the second substrate 20 may be 0.5 mm to 2.5 mm. According to some embodiments of the present application, the thickness of the second substrate 20 may be 0.8 mm to 2.0 mm. When the thickness of the second substrate 20 is 0.5 mm to 2.5 mm, the thickness of the second substrate 20 is appropriate, and the battery pack cover 100 occupies a small space. This ensures effective support strength and can delay heat transfer in the event of thermal runaway. In the event of a fire, if the second substrate 20 is a composite plate within the above thickness range, the matrix resin of the composite material gradually carbonizes and falls off as the temperature rises. However, the reinforcing fibers have good high-temperature resistance. When the matrix resin carbonizes and falls off, the physical structure of the reinforcing fibers is still maintained, allowing for significant delay in heat transfer. In addition, the physical structure of the reinforcing fiber may provide additional support between the battery pack and the metal plate, thereby avoiding arcing between the battery pack and the metal plate due to an excessively small gap, and effectively improving the breakdown voltage resistance performance of the battery pack cover 100.

[0017] According to some embodiments of the present application, the thermal conductivity b2 of the second substrate 20 may be 0.03 W / (m·K) to 0.12 W / (m·K). Therefore, the heat insulating performance of the battery pack cover 100 can be significantly improved through the configuration of the second substrate 20, thereby effectively solving the problem of low power consumption of the battery pack at low temperatures.

[0018] See Figures 2 and 3. According to some embodiments of the present application, the first substrate 10 may be a full layer of metal plate.

[0019] See FIG. 3. According to some embodiments of the present application, when the first substrate 10 is a full-layer metal plate, the second substrate 20 may be located on only one side of the metal plate, and the second substrate 20 may be a composite plate. In this case, the surface of the metal plate away from the composite plate may have a corrosion-resistant layer, and the material of the corrosion-resistant layer may be epoxy resin. In actual use, the composite plate needs to be arranged facing the functional module, such as facing the battery module. The composite plate is used to cover one side of the metal plate, and a corrosion-resistant layer may be formed on the surface of the metal plate not covered by the composite plate through an electrophoresis process to ensure the corrosion resistance of the metal plate, thereby achieving a balance between the thermal insulation performance and the electrical insulation performance of the battery pack cover plate 100.

[0020] According to some embodiments of the present application, the electrophoresis process for forming the anticorrosion layer on the surface of the metal plate is not particularly limited, as long as the formed anticorrosion layer can improve the corrosion resistance of the metal plate. The electrophoresis process may include pretreatment of the metal plate, acid cleaning, alkali cleaning, phosphate treatment, epoxy coating, electrodeposition coating, baking, etc.

[0021] According to some embodiments of the present application, when the first substrate 10 is a full-layer metal plate and the second substrate 20 is located on one side surface of the metal plate, the orthogonal projection of the second substrate 20 onto the first substrate 10 may be located inside the first substrate 10. That is, the second substrate 20 is disposed on a partial region of at least one side surface of the first substrate 10. According to some embodiments of the present application, the second substrate 20 may be a composite material plate. The second substrate 20 may be disposed to correspond to a battery; for example, the second substrate 20 may completely cover the top surface of the battery.

[0022] Specifically, see FIG. 5 . The first substrate 10 is a full-layer metal plate, and the second substrate 20 is a composite plate, which is disposed on a partial region of one side surface of the first substrate 10. The surface of the metal plate on which the composite plate is disposed, but not covered by the composite plate, may be subjected to a surface anticorrosion treatment such as electrophoresis. During battery pack assembly, the composite plate may be disposed facing the battery, thereby fully utilizing the insulating performance of the battery pack cover 100 and effectively preventing arc discharge after short circuits or thermal runaway. When the composite plate is disposed on a partial region of one side surface of the metal plate, the edge of the metal plate extends beyond the edge of the composite plate. During manufacturing of the battery pack cover plate 100, a processing process such as a stamping process is used to form a hole structure in the edge region of the metal plate extending beyond the composite plate for connection with other components. This configuration prevents the composite plate from interfering with the hole structure. Therefore, after the composite plate is fixed to the metal plate through processes such as hot pressing or adhesive bonding, there is no need to re-form the hole structure in the composite plate through a stamping process. This simplifies the process flow and improves product yield. According to some other embodiments of the present application, when the composite plate is disposed on a partial region of one side surface of the metal plate, the distance between the edge of the metal plate and the edge of the composite plate may be 10 mm to 40 mm, thereby leaving a sufficient processing area for the hole structure. The surface of the metal plate may further have a corrosion-resistant layer, which may be made of epoxy resin. This allows the battery pack cover 100 to meet the thermal and electrical insulation requirements. When the battery pack cover 100 is used as a vehicle floor, this is beneficial for a fixed connection between the vehicle floor and the tray.

[0023] In the description of this application, "plurality" means two or more.

[0024] When the first substrate 10 is a metal plate, the thermal conductivity of the metal plate can be understood to be the thermal conductivity of the first substrate 10. When the reinforcing structure is disposed around the first substrate 10, the thermal conductivity is calculated based on the heat transfer in the direction Z of the first substrate 10, so that only the part of the metal plate with good thermal conductivity needs to be calculated. In this case, the thermal conductivity of the first substrate 10 is still the thermal conductivity of the metal plate.

[0025] According to some embodiments of the present application, the battery pack cover 100 may further include a third substrate 30, which is a composite plate. The third substrate 30 is located on the side of the first substrate 10 that is farther from the second substrate 20, i.e., the first substrate 10 is sandwiched between the second substrate 20 and the third substrate 30. The thickness a3 (mm) and thermal conductivity b3 (W / (m·K)) of the third substrate 30 must satisfy 6.67≦a1 / b1+a2 / b2+a3 / b3≦100.04. When the battery pack cover 100 includes a first substrate 10, a second substrate 20, and a third substrate 30 sandwiched between the first substrate 10 and the second substrate 20, a better corrosion protection effect against the metal plate can be achieved through the composite material plate, and higher structural strength and thermal resistance, as well as better thermal insulation performance, can be achieved when compared with a battery pack cover 100 including only the first substrate 10 and the second substrate 20.

[0026] According to some embodiments of the present application, the thickness of the third substrate 30 may be 0.5 mm to 2.5 mm. When the thickness of the third substrate 30 is 0.5 mm to 2.5 mm, the thickness of the third substrate 30 is appropriate, and the battery pack cover 100 occupies a small space. In the event of a thermal runaway such as a flame combustion, a physical gap may be formed accordingly, and the breakdown voltage resistance performance of the battery pack cover 100 can be effectively improved through the physical gap.

[0027] According to some embodiments of the present application, the thermal conductivity b3 of the third substrate 30 may be 0.03 W / (m·K) to 0.12 W / (m·K). Therefore, the heat insulating performance of the battery pack cover 100 can be significantly improved through the configuration of the third substrate 30, thereby effectively solving the problem of low power consumption of the battery pack at low temperatures.

[0028] See FIG. 2. According to some embodiments of the present application, when the first substrate 10 is a full layer of metal plate, the metal plate may be sandwiched between the first composite plate (i.e., the second substrate 20) and the second composite plate (i.e., the third substrate 30). The two composite plates are used to completely cover the upper and lower surfaces of the metal plate, which can effectively improve the overall rigidity of the battery pack cover 100. The composite plate can also effectively isolate the metal plate from a complex external environment and achieve anti-corrosion effects. According to some other embodiments of the present application, when the metal plate is sandwiched between the first composite plate (i.e., the second substrate 20) and the second composite plate (i.e., the third substrate 30), the dimensions of the metal plate need to be smaller than the dimensions of the composite plate, thereby achieving complete coverage of the metal plate by the composite plate.

[0029] According to some embodiments of the present application, the distance between the edge of the first composite plate and the edge of the metal plate when orthogonally projected onto the first composite plate may be 2 mm to 10 mm, thereby sealing the edge of the metal plate and physically isolating the metal plate from the outside world, while also meeting the requirements for thermal insulation, electrical insulation, and strength of the battery pack cover 100 and preventing the metal plate from rusting or corroding.

[0030] According to some embodiments of the present application, the battery pack cover 100 may further include a reinforcing structure, which is a composite plate, and the reinforcing structure is at least partially disposed around the metal plate. Specifically, see FIG. 4 . The composite plate may include a first composite plate (i.e., the second substrate 20) and a second composite plate (i.e., the third substrate 30). The metal plate of the first substrate 10 may include at least one sub-metal plate 111, and a third composite plate 123 (i.e., the reinforcing structure) of the frame structure is disposed around the sub-metal plate 111. The metal plate (including at least one sub-metal plate 111) and the third composite plate 123 together form an intermediate plate, which is sandwiched between the first composite plate (i.e., the second substrate 20) and the second composite plate (i.e., the third substrate 30). The two composite plates are used to completely cover the upper and lower surfaces of the metal plate, effectively improving the overall rigidity and thermal insulation performance of the battery pack cover 100. The composite plates also effectively isolate the metal plate from the complex external environment and provide corrosion protection. Furthermore, the metal plate can be divided into multiple sub-metal plates fastened to each other via a third composite plate, effectively reducing the overall weight of the battery pack cover 100. During assembly of the battery pack cover 100, hanging points may be provided on the third composite plate to prevent corrosion or rust of the metal plates due to cutting. Furthermore, by providing hanging points on the third composite plate to fasten the battery pack cover 100, the metal processing techniques required for all layers of the metal plate structure can be omitted, significantly reducing preparation costs.

[0031] According to some embodiments of the present application, the distance between the edge of the secondary metal plate and the outer edge of the third composite material plate is 10 mm to 50 mm, thereby realizing corrosion protection of the edge and ensuring the overall rigidity of the upper cover. The outer edge of the third composite material plate 123 is the edge of the third composite material plate 123 that is away from the secondary metal plate 111. In this way, the edge of the metal plate is sealed and physically isolated from the outside world, while meeting the electrical insulation performance and strength requirements of the battery pack cover 100 and preventing the metal plate from rusting or corroding.

[0032] According to some embodiments of the present application, the method for combining and fixing the metal plate and the composite plate in the present application is not particularly limited. For example, a hot pressing process may be used, in which the composite plate flows during the hot pressing to fill the surface of the metal plate, and then the composite plate is fixed to the metal plate after hardening, thereby realizing the composite formation of the metal plate and the composite plate.

[0033] The battery pack cover 100 of the present application has at least the following advantages.

[0034] 1. In the present application, the strength and rigidity of the battery pack cover 100 are substantially improved by composite formation of a metal plate and a high-strength, high-modulus composite material plate, thereby providing better protection for the cells against the impact of the battery pack cover 100.

[0035] 2. Because the thermal conductivity of the composite plate is lower than that of the metal plate, the battery pack cover 100 of this application has higher thermal resistance and better thermal insulation performance than the battery pack cover 100 made of pure metal, thereby effectively solving the problem of low power consumption of the battery pack at low temperatures.

[0036] 3. The surface of the battery pack cover 100 in this application that comes into contact with the current-carrying components inside the battery pack is a composite material plate, so the electrical insulation properties of the composite material plate can meet the high-voltage safety requirements and prevent the risk of arc discharge caused by small electrical gaps.

[0037] 4. When a battery pack experiences thermal runaway, the protective layer on the metal surface of a conventional metal battery pack cover 100 is burned by the flame and peeled off, exposing the metal. When the battery pack cover 100 of the present application is burned by the flame, the reinforcing fiber of the battery pack cover can provide physical isolation, thereby preventing arc discharge and dielectric breakdown caused by contact between the metal plate and the conductor, and improving the safety of passengers in the vehicle.

[0038] In the description of this application, the orientations or positional relationships indicated by terms such as "width," "thickness," "top," and "bottom" are based on the orientations or positional relationships shown in the accompanying drawings, and are intended merely to facilitate and simplify the description of this application, and are not intended to indicate or suggest that the devices or elements described have a particular orientation or are required to be constructed and operated in a particular orientation. Therefore, such terms should not be understood as limitations on this application.

[0039] In this application, all numerical values ​​disclosed herein are approximate, regardless of whether the word "about" or "approximately" is used. Each numerical value may vary by less than 10%, or by a difference considered reasonable by one of ordinary skill in the art, such as 1%, 2%, 3%, 4%, or 5%.

[0040] According to some embodiments of the present application, a method for measuring a thickness of a substrate includes measuring the thickness of the substrate using a Vernier scale.

[0041] According to some embodiments of the present application, a method for measuring the thermal conductivity of a substrate includes conducting a test according to ASTM C518-21 test method.

[0042] In another aspect of the present application, the present application proposes a battery pack including a battery, a tray, and the above-mentioned battery pack cover 100, where the battery pack cover 100 and the tray are connected to form a receiving cavity for receiving the battery. Therefore, the battery pack has all the features and advantages of the above-mentioned battery pack cover 100. The details will not be described again here.

[0043] According to some embodiments of the present application, the second substrate 20 may be disposed facing the receiving cavity in the battery pack, so that the excellent thermal and electrical insulating properties of the second substrate 20 can be utilized to improve the structural stability and safety performance of the battery pack.

[0044] In yet another aspect of the present application, the present application provides a vehicle including a vehicle floor, the vehicle floor including the above-described battery pack cover 100. Thus, the vehicle has all the features and advantages of the above-described battery pack cover 100, the details of which will not be described again here.

[0045] See Figure 1. According to some embodiments of the present application, a vehicle may include a body chassis assembly, which includes a body floor, a functional module 200, and a tray 300. The body floor and the tray 300 sandwich the functional module 200, and the body floor and the tray are connected to form a receiving cavity for receiving the functional module.

[0046] According to some embodiments of the present application, the metal plate should cover the functional module as much as possible, for example, the area of ​​the metal plate may match the cross-sectional area of ​​the functional module, which can effectively improve the pedal strength of the vehicle floor.

[0047] According to some embodiments of the present application, silicone foam may be used to fit and compress the surface of the vehicle body floor and the bottom beams of the entire vehicle to achieve a sealing effect.

[0048] According to some embodiments of the present application, the functional module may include a battery module. Specifically, the functional module may include at least one of a cell, a battery module, and a battery pack.

[0049] The solution of the present application will be described below using specific embodiments. Please note that the following embodiments are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If no specific techniques or conditions are specified in the embodiments, they shall be in accordance with the techniques or conditions described in the literature or product instructions in the field. All reagents and equipment used without indicating the manufacturer are conventional products available on the market.

[0050] The structure of the battery pack cover in Examples 1 to 16 and 22 is shown in Figure 3, where the second substrate covers one side surface of the first substrate. The structure of the battery pack cover in Examples 17, 20 and 21 is shown in Figure 2, where the first substrate is sandwiched between the second substrate and the third substrate. The structure of the battery pack cover in Example 18 is shown in Figure 4, where the first substrate is sandwiched between the second substrate and the third substrate, and the first substrate includes two sub-metal plates, and a reinforcing structure is disposed around the sub-metal plates. The structure of the battery pack cover in Example 19 is shown in Figure 5, where the second substrate is disposed in a partial region of one side surface of the first substrate.

[0051] The structure of the battery pack cover in Comparative Examples 1 and 2 is shown in Figure 3, where the second substrate covers one side of the first substrate. The specific parameters of the substrates in each Example and Comparative Example are shown in Table 1. [Table 1]

[0052] The following performance tests were conducted on the battery pack covers provided in the above examples and comparative examples.

[0053] Deformation: A force of 75 kgf was applied to a 10 mm diameter round rod to press into one side of the battery pack cover, and the depth of deformation was tested using a vernier scale and a spirit level.

[0054] Insulation performance: The time required for the battery pack temperature to drop from 20°C to 0°C in a -10°C environment.

[0055] Electrical insulation and high voltage resistance: In accordance with GB / T 1408.1-2016 - Electrical strength of insulating materials - Test methods - Part 1: Tests at power frequencies, DC 1000V was applied to both main surfaces of the battery pack cover for 60 seconds to test insulation resistance. In accordance with GB / T 1408.1-2016 - Electrical strength of insulating materials - Test methods - Part 1: Tests at power frequencies, AC 3000V was applied to both main surfaces of the battery pack cover for 60 seconds to record breakdown and sparks, and test leakage current.

[0056] High temperature and high voltage resistance: A flame from a butane torch (with a flame temperature of approximately 1000°C) was used to spray perpendicularly onto the battery pack cover, and the side on which the composite plate was located was placed in the outer flame area for 30 minutes, and the AC 1000V dielectric withstand voltage after being exposed to the fire was recorded.

[0057] The test results are shown in Table 2. [Table 2]

[0058] The test results show that the insulation performance, extrusion resistance, high-voltage resistance, and high-temperature and high-voltage resistance of the battery pack covers in Examples 1 to 22 all meet the specifications. Specifically, for the battery pack covers in Examples 1 to 22, the time required for the battery pack temperature to drop from 20°C to 0°C in a -10°C environment is longer than 10 hours. For the battery pack covers in Examples 1 to 22, when a 75 kgf force is applied to one side of the battery pack cover with a 10 mm diameter round rod and the deformation depth is tested using a vernier scale and a spirit level, the battery pack cover deforms by less than 2 mm. In accordance with GB / T 1408.1-2016 - Electrical Strength of Insulating Materials - Test Methods - Part 1: Tests at Power Frequencies, when DC 1000 V is applied to both main surfaces of the battery pack covers in Examples 1 to 22 for 60 seconds, the insulation resistance exceeds 50 GΩ. According to "GB / T 1408.1-2016 - Electrical Strength of Insulating Materials - Test Methods - Part 1: Tests at Power Frequencies," when AC 3000V is applied to the two main surfaces of the battery pack covers in Examples 1 to 22 for 60 seconds, no breakdown or sparks occur, and the leakage current is less than 3mA. When a flame from a butane torch (with a flame temperature of approximately 1000°C) is used to spray perpendicularly onto the battery pack covers in Examples 1 to 22, and the side on which the composite plate is located is placed in the flame in the outer flame area for 30 minutes, the requirement for AC 1000V dielectric withstand voltage after being exposed to the fire is met.

[0059] In Comparative Example 1, the thickness of the first substrate was 0.8 mm, the thermal conductivity of the first substrate was 46 W / (m·K), and the thickness of the second substrate was 0.8 mm, the thermal conductivity of the second substrate was 0.15 W / (m·K), where a1 / b1 + a2 / b2 was 5.351, which does not satisfy 6.67≦a1 / b1 + a2 / b2≦100.04. The thermal conductivity of the second substrate was too high, and the insulating performance of the battery pack cover was insufficient. In a -10°C environment, it took only 9.2 hours for the battery pack temperature to drop from 20°C to 0°C. In Comparative Example 2, the first substrate was 0.5 mm thick and had a thermal conductivity of 30 W (m·K), while the second substrate was 2.5 mm thick and had a thermal conductivity of 0.2 W / (m·K). Here, a1 / b1 + a2 / b2 was 125.017, which does not satisfy the relationship 6.67≦a1 / b1 + a2 / b2≦100.04. The test results showed that when AC 3000V was applied to both sides of the battery pack cover for 60 seconds, breakdown and sparks occurred, and the leakage current was 5.2 mA, which did not meet the dielectric withstand voltage performance requirements.

[0060] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. All patents and publications referenced in this application are incorporated herein by reference in their entirety. The terms "comprises" or "comprises" are open expressions, i.e., include the content specified in this application but do not exclude other content.

[0061] In the description herein, references such as "one embodiment," "another embodiment," and the like mean that a specific feature, structure, material, or characteristic described with reference to that embodiment is included in at least one embodiment of the present application. In the description herein, exemplary expressions of the aforementioned terms do not necessarily refer to the same embodiment or example. Also, in the description herein, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more of the embodiments or examples. Furthermore, a person skilled in the art may combine and associate different embodiments or examples, and features of different embodiments or examples, described herein without mutually contradicting each other. It should also be noted that the terms "first" and "second" used herein are intended for descriptive purposes only and should not be understood as an indication or suggestion of the relative importance of the technical features indicated or as an implicit indication of their quantity.

[0062] Although the embodiments of the present application have been illustrated and described above, it should be understood that the foregoing embodiments are exemplary and should not be construed as limitations on the present application. Those skilled in the art may make changes, modifications, substitutions, and variations to the foregoing embodiments within the scope of the present application. [Explanation of symbols]

[0063] 10 First substrate 20 Second substrate 30 Third board 100 Battery Pack Covers 111 Sub-metal plate 123 Third Composite Plate 200 Functional Modules 300 trays

Claims

1. A first substrate (10), the thickness of which is a １ (mm), and the thermal conductivity of the first substrate (10) is b １ (W / (m·K)) a first substrate (10); A second substrate (20), the second substrate (20) being located on one side surface of the first substrate (10), the thickness of the second substrate (20) being a ２ (mm), and the thermal conductivity of the second substrate (20) is b ２ (W / (m·K)) Equipped with The first substrate (10) and the second substrate (20) are 6.67≦a １ / b １ +a ２ / b ２ ≦100.04 Satisfy the condition that Battery pack cover (100).

2. a １ is 0.4 mm to 2.5 mm, and b １ The battery pack cover (100) of claim 1, wherein the thermal conductivity is 40 W / (m·K) to 80 W / (m·K).

3. The battery pack cover (100) of claim 2, wherein the first substrate (10) is a metal plate.

4. 4. The battery pack cover (100) of claim 3, further comprising a reinforcing structure, the reinforcing structure being a composite plate, the reinforcing structure being at least partially disposed around the metal plate.

5. a ２ is 0.5 mm to 2.5 mm, and b ２ The battery pack cover (100) of claim 1, wherein the resistance is 0.03 W / (m·K) to 0.12 W(m·K).

6. The battery pack cover (100) of claim 5, wherein the second substrate (20) is a composite plate.

7. 7. The battery pack cover (100) of claim 6, wherein an orthogonal projection of the second substrate (20) onto the first substrate (10) is located inside the first substrate (10).

8. a ２ The battery pack cover (100) of claim 6, wherein the thickness is between 0.8 mm and 2.0 mm.

9. The battery pack cover (100) further comprises a third substrate (30), the third substrate (30) being a composite plate, the third substrate (30) being located on the side of the first substrate (10) that is farther from the second substrate (20), and the thickness of the third substrate (30) is ３ (mm), and the thermal conductivity of the third substrate (30) is b ３ (W / (m·K)), where 6.67≦a １ / b １ +a ２ / b ２ +a ３ / b ３ 10. The battery pack cover (100) of claim 1, wherein: ≦100.

04.

10. a ３ is 0.5 mm to 2.5 mm, and b ３ The battery pack cover (100) of claim 9, wherein the thermal conductivity is 0.03 W / (m·K) to 0.12 W / (m·K).

11. 11. The battery pack cover (100) of claim 6, wherein the material of the composite plate comprises a matrix resin and reinforcing fibers, the matrix resin comprising at least one of an epoxy resin, a polyamide resin, a polyurethane resin, a polyimide resin, a polysulfone resin, and a phenolic resin, and the reinforcing fibers comprising at least one of glass fibers and ceramic fibers.

12. 12. A battery pack comprising: a battery; a tray; and the battery pack cover according to any one of claims 1 to 11, wherein the battery pack cover and the tray are connected to form a housing cavity for housing the battery.

13. The battery pack according to claim 12, wherein the second substrate (20) is disposed so as to face the receiving cavity.

14. A vehicle comprising a body floor, the body floor comprising a battery pack cover (100) according to any one of claims 1 to 11.

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