Heated film, battery pack, and vehicle

Abstract

The application discloses a heating film, a battery pack and a vehicle, the heating film comprising: a flexible base layer; a functional layer located on one side of the flexible base layer, the functional layer comprising a plurality of substructures arranged in an array, the substructures being circular, rectangular or parallelogram in shape; a plurality of conductive electrodes located on the side of the functional layer away from the flexible base layer, the plurality of conductive electrodes comprising first conductive electrodes and second conductive electrodes arranged at intervals and electrically opposite; and a buffer structure located on the side of the functional layer away from the flexible base layer and between the first conductive electrodes and the second conductive electrodes. Thus, the heating film is conducive to realizing uniform heat dissipation without dead angles, reducing the problems of local overheating or cold zones of traditional heating films, improving the electric-thermal conversion efficiency, having a wide temperature resistance range, meeting the use requirements of the vehicle in a low-temperature environment, and being low in cost and easy to realize industrial production.

Description

Technical Field

[0001] This application relates to the field of cryogenic heating technology, specifically to heating films, battery packs, and vehicles. Background Technology

[0002] In low-temperature environments, lithium-ion batteries experience increased electrolyte viscosity and hindered lithium-ion migration, leading to capacity decay, decreased charge / discharge efficiency, and the risk of lithium plating. To address this issue, low-temperature battery heating technology has emerged, primarily divided into external heating and internal self-heating. External heating technology has become the mainstream solution due to its simple structure, fast response, and stable control. External heating technology heats the battery surface or the surrounding environment through an additional heat source. Related technologies utilize heating films for external battery heating; however, traditional heating films suffer from localized overheating or cold spots. Therefore, further improvements to heating films are still needed.

[0003] It should be noted that the above statements are only used to provide background information related to this application and do not necessarily constitute prior art. Utility Model Content

[0004] In a first aspect, this application proposes a heating film comprising: a flexible base layer; a functional layer located on one side of the flexible base layer, the functional layer comprising an array of substructures arranged in a circular, rectangular, or parallelogram shape; a plurality of conductive electrodes located on the side of the functional layer away from the flexible base layer, the plurality of conductive electrodes comprising a first conductive electrode and a second conductive electrode spaced apart and having opposite electrical polarities; and a buffer structure located on the side of the functional layer away from the flexible base layer, and positioned between the first conductive electrode and the second conductive electrode. The heating film of this application, with its array of functional layers on the surface of the flexible base layer, can reduce costs, facilitate uniform heat dissipation without dead zones, reduce the problem of localized overheating or cold spots in traditional heating films, improve electrothermal conversion efficiency, and has a wide temperature resistance range, meeting the requirements for vehicle use in low-temperature environments.

[0005] In addition, the heating film according to the above embodiments of this application may also have the following additional technical features:

[0006] In some embodiments of this application, the functional layer includes multiple substructures, each with a width of 0.2mm to 1.5mm and a distance of 1mm to 2mm between them. This dense arrangement of substructures facilitates uniform heat dissipation without dead zones, reducing the problem of localized overheating or cold spots in traditional heating films.

[0007] In some embodiments of this application, the ratio of the projected area of ​​the functional layer on the flexible substrate to the area of ​​the surface of the flexible substrate facing the functional layer is greater than or equal to 95%. This is beneficial for improving the electrothermal conversion efficiency.

[0008] In some embodiments of this application, the functional layer is tin oxide, indium oxide, and graphene; wherein, based on the total mass of the functional layer, the sum of the mass fractions of tin oxide and indium oxide is greater than or equal to 90%, and the mass fraction of graphene is 5% to 10%. Therefore, the aforementioned material composition has a high thermal response speed, which is beneficial for improving electrothermal conversion efficiency and has a long service life.

[0009] In some embodiments of this application, the thickness of the functional layer is 0.02 mm to 0.1 mm. This facilitates more uniform heating.

[0010] In some embodiments of this application, the thickness of the buffer structure is 0.1 mm to 0.2 mm. This helps to improve the buffering effect and mitigate thermal expansion.

[0011] In some embodiments of this application, the thicknesses of the first conductive electrode and the second conductive electrode are each independently 0.05 mm to 0.1 mm. This is beneficial for improving the heating power of the heating film.

[0012] In some embodiments of this application, the thickness of the flexible base layer is 0.1 mm to 0.3 mm. This balances flexibility and mechanical strength, thereby improving heating efficiency.

[0013] In some embodiments of this application, the thickness of the heating film is less than or equal to 0.3 mm. This allows for improved space utilization while maintaining heating speed.

[0014] In some embodiments of this application, the flexible base layer is made of polyethylene terephthalate. This allows for cost reduction while achieving reliable insulation and mechanical support.

[0015] In some embodiments of this application, the material of the buffer structure is polyimide, polyvinyl chloride, or thermally conductive adhesive. This is beneficial for further improving the buffering effect and mitigating thermal expansion.

[0016] In a second aspect, this application proposes a battery pack including a battery and the heating film described in the first aspect, wherein the heating film is at least partially attached to the surface of the battery, and the flexible base layer is disposed facing the battery. Therefore, this battery pack has a wide temperature resistance range, meeting the requirements for vehicle use in low-temperature environments.

[0017] In some embodiments of this application, the width of the buffer structure is L1, the widths of the first conductive electrode and the second conductive electrode are both L2, the width of the functional layer is L3, the width of the flexible base layer is L4, and the width of the battery is L, satisfying the following relationship:

[0018] (L1+2L2) / L3≥99%,

[0019] L3 / L4 ≥ 99%,

[0020] 0 ≤ L3 / L-1 ≤ 0.5%.

[0021] By satisfying the above relationships, the reliability and safety of the heating film under the multidimensional requirements of electro-thermal-mechanical systems can be ensured, while adapting to the stringent space constraints of the battery pack and improving the safety of the battery pack.

[0022] In a third aspect, this application proposes a vehicle including the battery pack described in the second aspect. This allows the vehicle to operate at low temperatures and has a longer service life. Attached Figure Description

[0023] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0024] Figure 1 This is a schematic diagram of the structure of a heating film according to an embodiment of this application;

[0025] Figure 2 This is a side view of the structure of a heating film according to an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of an embodiment of the present application where the functional layer is circular;

[0027] Figure 4 This is a schematic diagram of an embodiment of this application where the functional layer is rectangular;

[0028] Figure 5 This is a schematic diagram of an embodiment of this application where the functional layer is a parallelogram.

[0029] Explanation of reference numerals in the attached drawings: 1-flexible base layer, 2-functional layer, 3-buffer structure, 4-first conductive electrode, 5-second conductive electrode, 6-substructure. Detailed Implementation

[0030] The embodiments of this application are described in detail below, with examples of these embodiments shown in the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0031] 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 pertains; the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit this application; unless otherwise stated, the values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this application).

[0032] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are open-ended expressions, meaning they include what is specified in this application but do not exclude other aspects.

[0033] In the description of this application, all figures disclosed herein, whether or not the words "approximately" or "about" are used, are approximate values. Each figure may vary by less than 10% or by a difference that is considered reasonable by one of the art, such as 1%, 2%, 3%, 4%, or 5%.

[0034] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0035] In the description of this application, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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.

[0036] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. "First feature" and "second feature" may include one or more of the indicated feature.

[0037] In the description of this application, "A and / or B" can include any of the cases of A alone, B alone, or A and B, where A and B are merely examples and can be any technical feature connected by "and / or" in this application.

[0038] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0039] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0040] In the first aspect of this application, a heating film is provided, referring to... Figure 1 The heating film comprises: a flexible base layer 1; a functional layer 2, located on one side of the flexible base layer, the functional layer comprising an array of substructures arranged in an array, the substructures being circular, rectangular, or parallelogram-shaped; multiple conductive electrodes, located on the side of the functional layer away from the flexible base layer, the multiple conductive electrodes including a first conductive electrode 4 and a second conductive electrode 5 spaced apart and having opposite electrical polarities; and a buffer structure 3, located on the side of the functional layer away from the flexible base layer, and situated between the first and second conductive electrodes. The heating film of this application, with its array of functional layers on the surface of the flexible base layer, can reduce costs, facilitate uniform heat dissipation without dead zones, reduce the problem of localized overheating or cold spots in traditional heating films, improve electrothermal conversion efficiency, and has a wider temperature resistance range, meeting the requirements for vehicle use in low-temperature environments.

[0041] In addition, the heating film according to the above embodiments of this application may also have the following additional technical features:

[0042] In some embodiments of this application, the functional layer includes multiple substructures, the width of which is 0.2mm to 1.5mm (e.g., 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1mm, 1.2mm, or 1.5mm, etc.), and the distance between the substructures is 1mm to 2mm (e.g., 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, or 2mm, etc.). The substructures of the functional layer are circular in shape (e.g., ...). Figure 3 As shown), rectangle (as shown) Figure 4 (as shown) or parallelogram (such as) Figure 5 As shown (in the image), it can be formed through a nanoscale coating process. It can be understood that, referring to... Figure 4 Adjacent substructures can be connected end-to-end to form a continuous structure, facilitating continuous coating and improving production efficiency. Furthermore, the dense arrangement of substructures helps achieve uniform heat dissipation without dead zones, reducing the problems of localized overheating or cold spots inherent in traditional heating films.

[0043] In some embodiments of this application, the ratio of the projected area of ​​the functional layer on the flexible substrate to the area of ​​the surface of the flexible substrate facing the functional layer is greater than or equal to 95%, for example, it can be 95%, 96%, 97%, 98%, or 99%. This is beneficial for improving the electrothermal conversion efficiency.

[0044] In some embodiments of this application, the functional layer is tin oxide, indium oxide, and graphene; wherein, based on the total mass of the functional layer, the sum of the mass fractions of tin oxide and indium oxide is greater than or equal to 90%, for example, it can be 90%, 91%, 92%, 93%, 94%, or 95%, etc., and the mass fraction of graphene is 5% to 10%, for example, it can be 5%, 6%, 7%, 8%, 9%, or 10%, etc. Tin oxide and indium oxide have an oxygen-deficient N-type semiconductor structure, and graphene has excellent electrical properties and thermal conductivity. The aforementioned material composition has a high thermal response speed, which is beneficial to improving the electrothermal conversion efficiency, enabling the heating film to heat up quickly, and extending its service life.

[0045] In some embodiments of this application, the thickness of the functional layer is 0.02 mm to 0.1 mm, for example, it can be 0.02 mm, 0.04 mm, 0.06 mm, 0.08 mm, or 0.1 mm. A thickness within this range facilitates more uniform heating.

[0046] In some embodiments of this application, the thickness of the buffer structure is 0.1 mm to 0.2 mm, for example, it can be 0.1 mm, 0.12 mm, 0.14 mm, 0.16 mm, 0.18 mm, or 0.2 mm. A thickness within this range is beneficial for improving the buffering effect and mitigating thermal expansion.

[0047] In some embodiments of this application, the thickness of the first conductive electrode and the second conductive electrode are each independently 0.05 mm to 0.1 mm, for example, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, or 0.1 mm. The first and second conductive electrodes can be made of copper strips. This is beneficial for improving the heating power of the heating film.

[0048] In some embodiments of this application, the thickness of the flexible base layer is 0.1mm to 0.3mm, for example, it can be 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, or 0.3mm. A thickness within the above range balances flexibility and mechanical strength, thereby improving heating efficiency.

[0049] In some embodiments of this application, the thickness of the heating film is less than or equal to 0.3 mm, for example, it can be 0.22 mm, 0.24 mm, 0.26 mm, 0.28 mm, or 0.3 mm, etc. (See reference...) Figure 2The thickness of the buffer structure is H1, the thickness of the first and second conductive electrodes is H2, the thickness of the functional layer is H3, the thickness of the flexible base layer is H4, and the thickness of the heating film is H1 + H3 + H4. The thickness of the heating film within the above range can improve space utilization while maintaining heating speed.

[0050] In some embodiments of this application, the flexible base layer is made of polyethylene terephthalate (PET). This allows for cost reduction while achieving reliable insulation and mechanical support.

[0051] In some embodiments of this application, the material of the buffer structure is polyimide (PI), polyvinyl chloride (PVC), or thermally conductive adhesive. This is beneficial for further improving the buffering effect and mitigating thermal expansion.

[0052] The heating film described in this application has at least the following advantages:

[0053] (1) The shape and thickness of the functional layer are controllable, which can achieve uniform heat dissipation without dead corners, reduce the problem of local overheating or cold areas in traditional heating films, and reduce costs, making it easy to achieve industrial production.

[0054] (2) It effectively improves the electrothermal conversion efficiency, has a wide temperature range, and meets the requirements for vehicle use in low-temperature environments.

[0055] In a second aspect, this application proposes a battery pack including a battery and the heating film described in the first aspect. The heating film is at least partially attached to the surface of the battery, and the flexible base layer is disposed facing the battery. A first conductive electrode and a second conductive electrode are supplied with current via an external power source. When the vehicle's built-in temperature sensor detects that the battery pack temperature is below 0°C, a DC power supply mode is used to create an electric field that causes the functional layer to release periodic far-infrared spectral lines of specific wavelengths, achieving rapid and uniform heating inside the battery. The internal temperature difference of the battery is ≤2°C, and heating stops when the battery temperature exceeds 35°C. Therefore, this battery pack has a wide temperature resistance range, meeting the requirements for vehicle use in low-temperature environments.

[0056] It should be noted that this heating film can be used not only for battery packs but also for the interior surfaces of vehicles, thereby increasing the temperature inside the vehicle. Those skilled in the art can flexibly configure it according to specific needs.

[0057] In some embodiments of this application, reference is made to Figure 2 The width of the buffer structure is L1, the widths of the first conductive electrode and the second conductive electrode are both L2, the width of the functional layer is L3, the width of the flexible base layer is L4, and the width of the battery is L, satisfying the following relationship:

[0058] (L1+2L2) / L3≥99%,

[0059] L3 / L4 ≥ 99%,

[0060] 0 ≤ L3 / L-1 ≤ 0.5%.

[0061] By satisfying the above relationships, the buffer structure, the first conductive electrode, and the second conductive electrode can cover most of the functional layer, which in turn can cover most of the flexible substrate and the battery. This ensures the reliability and safety of the heating film under the multi-dimensional requirements of electro-thermal-mechanical systems, while also adapting to the stringent space constraints of the battery pack and improving the safety of the battery pack.

[0062] In a third aspect, this application proposes a vehicle including the battery pack described in the second aspect. This allows the vehicle to operate at low temperatures and has a longer service life.

[0063] The following specific embodiments illustrate the solution of this application. It should be noted that these embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product manual. Materials whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0064] Examples of implementations of this application are shown in Table 1.

[0065] Table 1. Examples and Test Results

[0066]

[0067] Test method:

[0068] (1) Heating rate: The surface temperature change of the thermally conductive film is recorded in real time using a high-precision temperature sensor (such as a thermocouple). The heating rate is obtained by calculating the ratio of the temperature difference to the duration over a specific time period, using the following formula:

[0069] Heating rate = (Terminal temperature - Initial temperature) / Heating time, where the units of terminal temperature and initial temperature are °C, and the unit of heating time is min;

[0070] (2) Electrothermal conversion efficiency:

[0071] Input power measurement: Use tools such as power meters and multimeters to measure the voltage, current and power factor of the equipment, and calculate the input electrical energy (unit: watts / W). Output heat measurement: Measure the heat energy generated by the heating equipment through heat flow sensors or calorimeters, usually in joules (J).

[0072] Efficiency calculation: According to the formula: electrothermal conversion efficiency = (output useful heat / input total electrical energy) × 100%, the calculation results need to exclude the influence of environmental heat loss (such as thermal radiation and convection).

[0073] As can be seen from Table 1, the heating film of this application has an electrothermal conversion efficiency of ≥99%, which can achieve efficient and uniform heating of the battery, battery pack and the whole vehicle.

[0074] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A heating film, characterized in that, include: Flexible base layer; A functional layer is located on one side of the flexible base layer. The functional layer includes multiple substructures arranged in an array. The shape of the substructures is circular, rectangular, or parallelogram. Multiple conductive electrodes are located on the side of the functional layer away from the flexible base layer. The multiple conductive electrodes include a first conductive electrode and a second conductive electrode that are spaced apart and have opposite electrical properties. A buffer structure is located on the side of the functional layer away from the flexible base layer and between the first conductive electrode and the second conductive electrode.

2. The heating film according to claim 1, characterized in that, The functional layer includes multiple substructures, each with a width of 0.2mm to 1.5mm and a distance of 1mm to 2mm between them. The ratio of the projected area of ​​the functional layer on the flexible substrate to the area of ​​the surface of the flexible substrate facing the functional layer is greater than or equal to 95%.

3. The heating film according to claim 1 or 2, characterized in that, The functional layer comprises tin oxide, indium oxide, and graphene; wherein, based on the total mass of the functional layer, the sum of the mass fractions of the tin oxide and the indium oxide is greater than or equal to 90%, and the mass fraction of the graphene is 5% to 10%.

4. The heating film according to claim 3, characterized in that, The thickness of the functional layer is 0.02mm to 0.1mm.

5. The heating film according to claim 1, characterized in that, The thickness of the buffer structure is 0.1 mm to 0.2 mm; and / or The thickness of the first conductive electrode and the second conductive electrode are each independently 0.05 mm to 0.1 mm; and / or The thickness of the flexible base layer is 0.1mm to 0.3mm.

6. The heating film according to claim 1, characterized in that, The thickness of the heating film is less than or equal to 0.3 mm.

7. The heating film according to claim 1, characterized in that, The flexible base layer is made of polyethylene terephthalate; and / or The material of the buffer structure is polyimide, polyvinyl chloride, or thermally conductive adhesive.

8. A battery pack, characterized in that, The device includes a battery and a heating film according to any one of claims 1 to 7, wherein the heating film is at least partially attached to the surface of the battery, and the flexible base layer is disposed toward the battery.

9. The battery pack according to claim 8, characterized in that, The width of the buffer structure is L1, the widths of the first conductive electrode and the second conductive electrode are the same, both being L2, the width of the functional layer is L3, the width of the flexible base layer is L4, and the width of the battery is L, satisfying the following relationship: (L1+2L2) / L3≥99%, L3 / L4 ≥ 99%, 0 ≤ L3 / L-1 ≤ 0.5%.

10. A vehicle, characterized in that, The battery pack includes any one of claims 8 to 9.

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