Heat-conducting insulating film for high-power PTC (Positive Temperature Coefficient)

Abstract

The utility model relates to a heat-conducting insulating film for a high-power PTC (Positive Temperature Coefficient), which comprises a polyimide film layer, a heat-conducting layer is arranged on one surface of the polyimide film layer, a heat-conducting silica gel layer is arranged on the other surface of the polyimide film layer, the heat-conducting layer comprises a slip agent layer and a thermoplastic heat-conducting layer, the slip agent layer is sprayed on one surface of the thermoplastic heat-conducting layer, and the thermoplastic heat-conducting layer is coated on the other surface of the heat-conducting silica gel layer. And the other surface of the thermoplastic heat conduction layer is attached to the polyimide film layer. The heat-conducting insulating film for the high-power PTC is low in thermal resistance, good in heat-conducting effect and good in lubricity, and can prevent the situation of interface separation failure during high and low temperature work.

Description

Technical Field

[0001] This utility model relates to the field of thermally conductive insulating films, and in particular to a thermally conductive insulating film for high-power PTC. Background Technology

[0002] Positive temperature coefficient (PTC) thermistor ceramics are ferroelectric ceramics with semiconductor properties. Their resistance increases and power decreases as temperature rises, and decreases and power increases as temperature falls, producing a thermostat-like effect. Existing high-power PTC ceramic electric heating components often employ a PTC ceramic sheet covered with planar electrodes, pressed or welded to a metal electrode sheet, and then coated with a polyimide (PI) insulating film and a thermally conductive silicone sheet for heat conduction and insulation. While the thermally conductive silicone sheet has good thermal conductivity, the high rigidity of the polyimide film results in poor wetting ability at the thermal interface, leading to a high overall thermal resistance. This results in poor heat dissipation, severely hindering the removal of heat from the PTC ceramic, causing low thermal efficiency and decreased reliability over long-term use. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a thermally conductive insulating film for high-power PTC. This thermally conductive insulating film not only has low thermal resistance and good thermal conductivity, but also has good lubricity, which can prevent interface separation failure during high and low temperature operation.

[0004] The technical solution adopted by this utility model to solve its technical problem is: a thermally conductive insulating film for high-power PTC, including a polyimide film layer, a thermally conductive layer is provided on one side of the polyimide film layer, and a thermally conductive silicone layer is provided on the other side of the polyimide film layer. The thermally conductive layer includes a slip agent layer and a thermoplastic thermally conductive layer. The slip agent layer is sprayed on one side of the thermoplastic thermally conductive layer, and the other side of the thermoplastic thermally conductive layer is attached to the polyimide film layer.

[0005] In one embodiment, the thermal conductivity of the thermally conductive silicone layer of the high-power PTC thermally conductive insulating film is 3 W / m·K-8 W / m·K, and the thermal conductivity of the thermoplastic thermally conductive layer is 0.4 W / m·K-4 W / m·K.

[0006] In one embodiment, the slip agent layer of the high-power PTC thermally conductive insulating film is talc or boron nitride, and the powder particles of the slip agent layer are 0.1um-3um.

[0007] In one embodiment, the thickness of the thermoplastic thermally conductive layer of the high-power PTC thermally conductive insulating film is 0.01mm-0.1mm.

[0008] In one embodiment, the thickness of the thermally conductive silicone layer of the thermally conductive insulating film for the high-power PTC is 0.15mm-0.3mm.

[0009] The beneficial effects of this application are as follows:

[0010] This application provides a thermally conductive insulating film for high-power PTC devices. The thermally conductive insulating film uses a polyimide film layer as a carrier, and a thermoplastic thermally conductive layer and a thermally conductive silicone layer are respectively disposed on both sides of the polyimide film layer. A lubricant layer is disposed on the side of the thermoplastic thermally conductive layer away from the polyimide film layer. The resulting thermally conductive insulating film has excellent thermal properties, which significantly reduces the overall thermal resistance. It also has good lubrication properties, which can prevent interface separation failure caused by device expansion and contraction during high and low temperature operation.

[0011] This high-power PTC thermally conductive insulating film uses a polyimide film layer as a carrier and is formed by a thermally conductive silicone layer with a thermal conductivity of 3W / m·K-8W / m·K and a thermoplastic thermally conductive layer with a thermal conductivity of 0.4W / m·K-4W / m·K. The resulting thermally conductive insulating film has low thermal resistance and good thermal conductivity.

[0012] The thermally conductive insulating film for high-power PTC uses a slip agent layer to greatly reduce the friction on the surface of the polyimide layer, reducing the possibility of damage to the polyimide film layer due to scratches from foreign objects, thereby extending the product's service life. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a thermally conductive insulating film for a high-power PTC according to an embodiment of this application;

[0014] in:

[0015] 1. Polyimide film layer; 2. Thermally conductive silicone layer; 3. Thermoplastic thermally conductive layer; 4. Slip agent layer. Detailed Implementation

[0016] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0017] like Figure 1 As shown, an embodiment of this application provides a thermally conductive insulating film for high-power PTC, including a polyimide film layer 1. A thermally conductive layer is disposed on one side of the polyimide film layer 1, and a thermally conductive silicone layer 2 is disposed on the other side of the polyimide film layer 1. The thermally conductive layer includes a slip agent layer 4 and a thermoplastic thermally conductive layer 3. The slip agent layer 4 is sprayed on one side of the thermoplastic thermally conductive layer 3, and the other side of the thermoplastic thermally conductive layer 3 is attached to the polyimide film layer 1.

[0018] Specifically, using a polyimide film layer 1 as a carrier, a thermoplastic thermally conductive layer 3 is attached to one side of the polyimide film layer 1. The thermoplastic thermally conductive layer 3 includes polyethylene-styrene copolymer, polyethylene-styrene-butadiene copolymer, polyethylene, polypropylene, hydrocarbon resin, EVA resin, etc., and has a certain thermal conductivity. A slip agent layer 4 is attached to the side of the thermoplastic thermally conductive layer 3 away from the polyimide film layer 1, giving the surface of the polyimide film better lubricity. This not only reduces the friction on the surface of the polyimide layer but also improves scratch resistance, preventing damage caused by punctures from metallic foreign objects during construction. When the device reaches the softening point of the thermoplastic thermally conductive layer 3 and the slip agent layer 4, the thermoplastic material and the slip agent layer 4 soften until they become a paste, exhibiting excellent interfacial wetting ability. This better wets the two-phase interface, thereby reducing thermal resistance and improving thermal conductivity. A thermally conductive silicone layer 2 is attached to the other side of the polyimide film layer 1, which provides good thermal conductivity and insulation properties.

[0019] In the above structure, a thermally conductive insulating film is formed by sequentially configuring a thermally conductive silicone layer 2, a polyimide film layer 1, a thermoplastic thermally conductive layer 3, and a lubricant layer 4. This thermally conductive insulating film has excellent thermal properties, which significantly reduces the overall thermal resistance, and also has good lubrication properties, which can prevent interface separation failure caused by the expansion and contraction of the device during high and low temperature operation.

[0020] like Figure 1 As shown, in one embodiment, the thermal conductivity of the thermally conductive silicone layer 2 of the high-power PTC thermally conductive insulating film is 3 W / m·K to 8 W / m·K, and the thermal conductivity of the thermoplastic thermally conductive layer 3 is 0.4 W / m·K to 4 W / m·K. The thermal conductivity of the thermally conductive silicone layer 2 is 3 W / m·K, 4.5 W / m·K, 6.2 W / m·K, 7 W / m·K, and 8 W / m·K, preferably 7 W / m·K. The thermal conductivity of the thermoplastic thermally conductive layer 3 is 0.4 W / m·K, 1.2 W / m·K, 2.4 W / m·K, 3 W / m·K, and 4 W / m·K, preferably 3 W / m·K. This configuration not only results in low thermal resistance but also good thermal conductivity.

[0021] like Figure 1 As shown, in one embodiment, the slip agent layer 4 of the high-power PTC thermally conductive insulating film is talc or boron nitride, and the particle size of the slip agent layer 4 is 0.1µm-3µm. The particle sizes of the slip agent layer 4 are 0.1µm, 0.2µm, 0.3µm, 0.5µm, 1.5µm, 2µm, 2.6µm, and 3µm, with 0.5µm boron nitride being preferred. This arrangement provides excellent lubrication, significantly reducing friction on the polyimide layer surface and minimizing damage to the polyimide film layer 1 caused by foreign object scratches, thereby extending the product's service life.

[0022] like Figure 1 As shown, in one embodiment, the thickness of the thermoplastic thermally conductive layer 3 of the high-power PTC thermally conductive insulating film is 0.01mm-0.1mm. The thicknesses of the thermally conductive layer are 0.01mm, 0.02mm, 0.04mm, 0.05mm, 0.08mm, and 0.1mm, with 0.02mm being preferred. This thermoplastic thermally conductive layer 3 not only has low thermal resistance but also good interfacial wetting effect.

[0023] like Figure 1 As shown, in one embodiment, the thickness of the thermally conductive silicone layer 2 of the high-power PTC thermally conductive insulating film is 0.15mm-0.3mm. The thicknesses of the thermally conductive silicone layer 2 are 0.15mm, 0.2mm, 0.26mm, and 0.3mm, with 0.2mm being preferred. This configuration of the thermally conductive silicone layer 2 provides good thermal conductivity and insulation performance.

[0024] Optimal Implementation Example:

[0025] Step 1: Attach a thermoplastic thermally conductive layer 3 to one side of the polyimide film layer 1. The thermal conductivity of the thermoplastic thermally conductive layer 3 is 3 W / m·K, and the thickness of the thermoplastic thermally conductive layer 3 is 0.02 mm.

[0026] Step 2: Spray a slip agent layer on the side of the thermoplastic thermally conductive layer 3 away from the polyimide film layer 1. The slip agent layer uses boron nitride with particles of 0.5um.

[0027] Step 3: Attach a thermally conductive silicone layer 2 to the other side of the polyimide film layer 1. The thermal conductivity of the thermally conductive silicone layer 2 is 7 W / m·K, and the thickness of the thermally conductive silicone layer 2 is 0.2 mm.

[0028] The thermal resistance of the thermally conductive insulating film formed above is approximately 0.18℃. 2 / W.

[0029] A conventional high-power PTC thermally conductive insulating film consists of a thermally conductive silicone layer 2 with a thermal conductivity of 5 W / m·K bonded to one side of a polyimide film layer 1, with a thermal resistance of approximately 0.4 °C. 2 / W. Patent document "CN219279780U" describes attaching thermally conductive silicone layers 2 with a thermal conductivity of 5 W / m·K to both sides of a polyimide film layer 1, resulting in a thermal resistance of approximately 0.3℃. 2 / W. The thermal resistance of this application is reduced by 55% and 40% respectively compared to the previous two methods. This thermally conductive insulating film has excellent thermal properties and good lubrication properties, which can prevent interface separation failure caused by device expansion and contraction during high and low temperature operation.

[0030] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A thermally conductive insulating film for high-power PTC, characterized in that, The device includes a polyimide film layer (1), a thermally conductive layer is provided on one side of the polyimide film layer (1), and a thermally conductive silicone layer (2) is provided on the other side of the polyimide film layer (1). The thermally conductive layer includes a slip agent layer (4) and a thermoplastic thermally conductive layer (3). The slip agent layer (4) is sprayed on one side of the thermoplastic thermally conductive layer (3), and the other side of the thermoplastic thermally conductive layer (3) is attached to the polyimide film layer (1).

2. The thermally conductive insulating film for high-power PTC according to claim 1, characterized in that, The thermal conductivity of the thermally conductive silicone layer (2) is 3W / m·K-8W / m·K, and the thermal conductivity of the thermoplastic thermally conductive layer (3) is 0.4W / m·K-4W / m·K.

3. The thermally conductive insulating film for high-power PTC according to claim 1, characterized in that, The slip agent layer (4) is talc or boron nitride, and the powder particles of the slip agent layer (4) are 0.1um-3um.

4. The thermally conductive insulating film for high-power PTC according to claim 1, characterized in that, The thickness of the thermoplastic thermally conductive layer (3) is 0.01mm-0.1mm.

5. The thermally conductive insulating film for high-power PTC according to claim 1, characterized in that, The thickness of the thermally conductive silicone layer (2) is 0.15mm-0.3mm.

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