Technical Field

The present application relates to an insulating composite plate, and more particularly to an insulating composite plate with an electromagnetic shielding function for applications requiring simultaneous electromagnetic shielding and insulation.

Background Art

Insulating plates are used to insulate various electronic devices or components to avoid failures caused by electronic short circuits and breakdowns between electronic devices or units, or electronic components in electronic devices or units, and to reduce the risks of fire of electronic devices or components, thereby ensuring the normal operation of various types of electronic components. For different uses of insulating plates, insulating films are required to have different operating characteristics.

Therefore, it is desirable to provide an insulating plate having excellent properties.

Summary of the Invention

According to a first aspect of the present application, an insulating composite plate is provided, comprising:

an upper plate layer and a lower plate layer, the upper plate layer and the lower plate layer being made of a thermoplastic material; and

a middle plate layer located between the upper plate layer and the lower plate layer, the middle plate layer being a metal mesh;

the upper surface of the middle plate layer and the lower surface of the upper plate layer are bonded together, and the lower surface of the middle plate layer and the upper surface of the lower plate layer are bonded together.

In the plate as described above, the upper plate layer and the lower plate layer are bonded together at the position of the openings of the metal mesh.

The plate as described above is characterized in that:

the insulating composite plate is configured for molding into a battery pack cover shape;

the battery pack cover is configured for mounting on a battery pack housing. The plate as described above is characterized in that:

the insulating composite plate is formed to have four walls extending from its peripheral edges to form a battery pack cover.

The plate as described above is characterized in that:

the thermoplastic material is a thermoplastic resin.

The plate as described above is characterized in that:

the insulating composite plate is made by cast heat press molding or co-extrusion process; in the manufacturing process, the thermoplastic material on the upper plate layer and/or the lower plate layer penetrates the openings of the metal mesh in a molten state, and comes into contact with the lower plate layer or the upper plate layer on the other side of the metal mesh; after the thermoplastic material in a molten state is solidified, the upper plate layer is integrated with the lower plate layer so that the metal mesh is locked between the upper plate layer and the lower plate layer.

In the plate as described above, the plate upper layer and the plate lower layer are bonded together without using an additional medium.

In the plate as described above, the thermoplastic resin forming the upper plate layer and the lower plate layer penetrates the openings of the metal mesh in a molten state, so that the upper plate layer and the lower plate layer are bonded together. In the plate as described above, the upper plate layer and the lower plate layer are made of the same material.

In the plate as described above, the plate upper layer and the plate lower layer are made of different kinds of materials.

In the plate as described above, the thermoplastic material may be selected from PP, PC or PET.

In the plate as described above, the thermoplastic material is PP. In the plate as described above, neither the upper plate layer nor the lower plate layer contains a flame retardant.

In the plate as described above, the upper plate layer and the lower plate layer contain a flame retardant.

In the plate as described above, the flame retardant is a halogen-containing flame retardant or a halogen-free flame retardant, the halogen-containing flame retardant being a bromine-containing flame retardant or a chlorine-containing flame retardant, the halogen-free flame retardant being a phosphorus-containing flame retardant or a nitrogen-containing or silicon-containing or sulfur- containing or inorganic flame retardant.

With the plate as described above, in the case of using a flame retardant in the upper plate layer and the lower plate layer, the flame retardancy rating of the plate is V-2 or VTM-2 or higher, or V-0 or VTM- 0, and meets the RoHS standard.

In the plate as described above, the metal mesh is made of copper, or another metal, or an alloy.

In the plate as described above, the metal mesh is made of copper or an alloy thereof.

In the plate as described above, the metal mesh has a specification of 20 openings to 400 openings, or 50 openings to 100 openings.

In the plate as described above, the thickness of the upper plate layer is 0.05 mm to 4.0 mm, or 0.43 mm to 2 mm; the thickness of the middle plate layer is 0.05 mm to 0.4 mm; the thickness of the lower plate layer is 0.05 mm to 4.0 mm, or 0.43 mm to 2 mm.

In the plate as described above, the plate has a thickness of 0.15 mm to 5.0 mm, or 0.75 mm to 4 mm, or 1.5 mm to 3 mm, the plate has a CTI of 250 volts or higher, or 600 volts or higher, and the plate has an RTI of 90°C or higher.

The plate as described above is produced by cast heat press molding or co-extrusion process.

According to a second aspect of the present application, a method for producing an insulating composite plate is provided, the method comprising:

(a) extruding particles of a first thermoplastic material on an extruder to melt it to form a first thermoplastic material in a molten state;

(b) the first thermoplastic material in a molten state flows out of the extruder and enters a head die through a connecting pipe and is formed into a first plate thermoplastic material in the head die;

(c) providing a metal mesh;

(d) simultaneously conveying the metal mesh and the first plate thermoplastic material to a cooling molding roll so that the first plate thermoplastic material is press-fitted on one surface of the metal mesh to form a press-fitted sheet composed of the first plate thermoplastic material and the metal mesh;

(f) extruding particles of a second thermoplastic material on the extruder to melt it to form a second thermoplastic material in a molten state;

(g) the second thermoplastic material in a molten state flows out of the extruder and enters the head die through the connecting pipe and is formed into a second plate thermoplastic material in the head die;

(h) simultaneously conveying the press-fitted sheet and the second plate thermoplastic material to the cooling molding roll so that the second plate thermoplastic material is press-fitted on the other surface of the metal mesh, forming the insulating composite plate comprising a middle plate layer composed of the metal mesh and an upper plate layer and a lower plate layer respectively composed of the first plate thermoplastic material and the second plate thermoplastic material.

In the method for producing an insulating composite plate as described above, the first thermoplastic material and the second thermoplastic material are each selected from PP, PC or PET. In the method for producing an insulating composite plate as described above, the first thermoplastic material and the second thermoplastic material are the same or different.

In the method for producing an insulating composite plate as described above, the metal mesh is provided by unwinding from a metal mesh roll to convey the metal mesh to the cooling molding roll.

In the method for producing an insulating composite plate as described above, the press-fitted sheet formed in step (d) is wound into a press-fitted sheet roll, and the press-fitted sheet is unwound from the press-fitted sheet roll to convey the press-fitted sheet to the cooling molding roll. In the method for producing an insulating composite plate as described above, the thicknesses of the upper plate layer and the lower plate layer are determined by controlling the speed at which the first plate thermoplastic material and the second plate thermoplastic material exit the head die and the rotational speed of the cooling molding roll.

The method for producing an insulating composite plate as described above comprises step (i) of heating the press-fitted sheet before step (h).

In the method for producing an insulating composite plate as described above, the thermoplastic material on the upper plate layer and/or the lower plate layer penetrates the openings of the metal mesh in a molten state, and comes into contact with the lower plate layer or the upper plate layer on the other side of the metal mesh; after the thermoplastic material in the molten state is solidified, the upper plate layer is integrated with the lower plate layer so that the metal mesh is locked between the upper plate layer and the lower plate layer.

According to a third aspect of the present application, a method for producing an insulating composite plate is provided, the method comprising:

(a) extruding particles of a first thermoplastic material on a first extruder to melt it to form a first thermoplastic material in a molten state;

(b) the first thermoplastic material in a molten state flows out of the first extruder and enters a first head die through a first connecting pipe and is formed into a first plate thermoplastic material in the first head die;

(c) extruding particles of a second thermoplastic material on a second extruder to melt it to form a second thermoplastic material in a molten state;

(d) the second thermoplastic material in a molten state flows out of the second extruder and enters a second head die through a second connecting pipe and is formed into a second plate thermoplastic material in the second head die;

(e) providing a metal mesh;

(f) simultaneously conveying the metal mesh, the first plate thermoplastic material, and the second plate thermoplastic material to a cooling molding roll so that the first plate thermoplastic material and the second plate thermoplastic material are respectively press-fitted on the two opposing surfaces of the metal mesh, forming the insulating composite plate comprising a middle plate layer composed of the metal mesh and an upper plate layer and a lower plate layer respectively composed of the first plate thermoplastic material and the second plate thermoplastic material. In the method for producing an insulating composite plate as described above, the first thermoplastic material and the second thermoplastic material in a molten state penetrate the openings of the metal mesh to come into contact with each other; after the first thermoplastic material and the second thermoplastic material in a molten state are solidified, they are integrated so that the metal mesh is locked between the upper plate layer and the lower plate layer.

In the method for producing an insulating composite plate as described above, the first thermoplastic material and the second thermoplastic material are each selected from PP, PC or PET.

In the method for producing an insulating composite plate as described above, the first thermoplastic material and the second thermoplastic material are the same or different.

In the method for producing an insulating composite plate as described above, the metal mesh is provided by unwinding from a metal mesh roll to convey the metal mesh to the cooling molding roll.

In the method for producing an insulating composite plate as described above, the thicknesses of the upper plate layer and the lower plate layer are determined by controlling the speed at which the first plate thermoplastic material and the second plate thermoplastic material exit the head die and the rotational speed of the cooling molding roll.

A composite plate provided by the present application has excellent insulation performance and electromagnetic shielding function, and is applicable to isolating various electronic components. Brief Description of the Drawings

These and other features and advantages of the present application can be better understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same parts, wherein:

Figure 1 is a schematic cross-sectional view of an insulating composite plate according to an embodiment of the present application; Figure 2 is another schematic cross-sectional view of the insulating composite plate shown in Figure 1 for schematically illustrating a state where the upper plate layer 101 and the lower plate layer 103 penetrate the openings 105 of the metal mesh 102 to be bonded together;

Figures 3A and 3B illustrate a cast heat press molding process of an insulating composite plate according to an embodiment of the present application;

Figure 4 shows a co-extrusion process of producing an insulating composite plate according to an embodiment of the present application;

Figure 5 is a top view of a metal mesh in an insulating composite plate of the present application;

Figure 6 is a schematic view of a battery pack cover made of an insulating composite plate of the present application;

Figure 7 is a schematic view of the battery pack cover in Figure 6 on the battery pack housing.

Specific Embodiments

Various embodiments of the present application will be described below with reference to the accompanying drawings, which form a part of this Specification. It should be understood that, although terms indicating directions, such as "front", "back", "upper", "lower", "left", and "right", are used in this application to describe various exemplary structural components and elements, these terms are used herein for convenience of illustration only and are determined on the basis of the exemplary orientations shown in the figures. Since the embodiments disclosed in the present application can be set in different directions, these terms indicating directions are merely illustrative and should not be construed as limiting. In the following drawings, the same reference numerals are used for the same components, and similar reference numerals are used for similar components to avoid redundant description.

Figure 1 shows a schematic cross-sectional view of an insulating composite plate 100 according to an embodiment of the present application. As shown in Figure 1, the plate 100 comprises an upper plate layer 101, a middle plate layer 102, and a lower plate layer 103 bonded together. The upper plate layer 101 and the lower plate layer 103 are made of a thermoplastic material so that the plate 100 has a good insulation effect. The thermoplastic material may be a thermoplastic resin. The thermoplastic materials used to make the upper plate layer 101 and the lower plate layer 103 may be the same or different. The thermoplastic material used to make the upper plate layer 101 and the lower plate layer 103 may be PP, PC or PET. In one embodiment, PP is used as the material of the upper plate layer 101 and the lower plate layer 103. The reasons are as follows: (1) PP is a non-toxic, odorless, tasteless milky white crystalline polymer with a density of 0.90 g/cm ³ to 0.91 g/cm ³ , which is one of the lightest varieties in all plastics. Therefore, when PP is selected as the material of the upper plate layer 101 and the lower plate layer 103, a plate 100 with a lighter overall weight can be obtained to meet the requirements for plate weight in an actual application (such as a battery pack cover plate for an electric vehicle); (2) In addition, PP as a hydrophobic polymer material with excellent electrical insulation properties. Use of PP as the material of the upper plate layer 101 and that of the lower plate layer 103 can allow the plate 100 to deliver better insulation performance; (3) The molding performance of PP is good, making it easy to obtain the plate 100 through a molding process; (4) PP has a melting point of 164°C to 170°C, and has good heat resistance. A product can be used under 125°C for a long period of time. It is not deformed under 150°C without external force, so that the plate 100 delivers the high-temperature resistance required in practical applications (for example, when it is used as a battery pack cover); (5) PP has very good chemical stability. Except being corroded by concentrated sulfuric acid, concentrated nitric acid, or strong oxidants, it is relatively stable to other chemical reagents, so that it can meet the solvent resistance performance requirement on the plate 100 in a practical application (such as the battery pack cover of an electric vehicle).

Optionally, a flame retardant or no flame retardant may be added to the thermoplastic material of the upper plate layer 101 and/or the lower plate layer 103. When a flame retardant is added to the thermoplastic material of the upper plate layer 101 and/or the lower plate layer 103, the flame retardant is a halogen-containing flame retardant or a halogen-free flame retardant, the halogen- containing flame retardant being a bromine-containing flame retardant or a chlorine-containing flame retardant, the halogen-free flame retardant being a phosphorus-containing flame retardant or a nitrogen-containing or silicon-containing or sulfur-containing or inorganic flame retardant. Whatever kind of flame retardant is added to the thermoplastic material of the upper plate layer 101 and/or the lower plate layer 103, the RoHS standard is met. In addition, the plate retardancy rating can reach V- 2 or VTM-2 or higher, and can even reach V-0 or VTM-0.

The middle plate layer 102 is located between the upper plate layer 101 and the lower plate layer 103. The middle plate layer 102 is a metal mesh, so that the insulating composite plate 100 of the present application has an electromagnetic shielding function. The metal mesh of the middle plate layer 102 is embedded in the surfaces of the upper plate layer 101 and the lower plate layer 103 to form a firm connection between the upper plate layer 101, the middle plate layer 102, and the lower plate layer 103. Figure 5 shows a schematic structural diagram for the metal mesh. The metal mesh may be copper or another metal, or an alloy of copper or another metal. In one embodiment, the metal mesh is copper or an alloy thereof. In another embodiment, the metal mesh is elemental copper. Due to the good ductility of copper, when elemental copper is used to manufacture the metal mesh of the middle plate layer 102, it is advantageous for the subsequent thermoforming to form the metal mesh. The number of openings of the metal mesh is related to the electromagnetic shielding effect and the forming and processing of a product. For the electromagnetic shielding effect of the metal mesh, the larger the number of openings of the metal mesh is, the better it is; for the forming and processing of a metal mesh product, the smaller the number of openings of the metal mesh is, the better it is. Considering the two factors comprehensively, the number of openings of the metal mesh is usually 20 to 400, or 50 to 300, or 50 to 200, or 50 to 100, or 80. The diameter of a metal wire may be 0.01 mm to 0.2 mm, the spacing between adjacent metal wires may be 0.05 mm to 0.3 mm, and the thickness of the metal mesh may be 0.05 mm to 0.4 mm. The number of metal mesh openings disclosed in the present application makes it possible to achieve a good electromagnetic shielding effect while facilitating the forming and processing of a product.

In the process of bonding the upper plate layer 101, the middle plate layer 102, and the lower plate layer 103, at least one of the upper plate layer 101 and the lower plate layer 103 is in a molten state. Thus, the thermoplastic materials of the upper plate layer 101 and/or the lower plate layer 103 in a molten state penetrate the openings of the metal mesh to come into contact with the lower plate layer 103 or the upper plate layer 101 on the other side of the metal mesh. After the molten thermoplastic material cools and solidifies, it is bonded to the lower plate layer and/or the upper plate layer 101 to form an insulating composite plate of the present application.

Figure 2 is another schematic cross-sectional view of the plate 100, for schematically showing a state where the upper plate layer 101 and the lower plate layer 103 are bonded together through the openings of the metal mesh. As shown in Figure 2, at the position of the mesh openings 105 of the metal mesh of the middle plate layer 102, the thermoplastic materials of the upper plate layer 101 and/or the lower plate layer 103 penetrate the openings 105 of the metal mesh and are bonded together. As shown in Figure 2, the portions of the upper plate layer 101 and the lower plate layer 103 that penetrate the mesh openings 105 of the metal mesh are bonded as if formed integrally. By this type of bonding, the upper plate layer 101 and the lower plate layer 103 can be bonded together without using any other medium, for example, glue. In addition, the method for bonding the upper plate layer 101 and the lower plate layer 103 of the insulating composite plate 100 of the present application is such that the upper plate layer 101 and the lower plate layer 103 are tightly bonded together for a long time, as if formed integrally. Therefore, there is no separation between the upper plate layer 101, the middle plate layer 102, and the lower plate layer 103. In addition, there is no gap between the upper plate layer 101, the middle plate layer 102, and the lower plate layer 103. Thus, moisture cannot enter between the upper plate layer 101, the middle plate layer 102, and the lower plate layer 103 to corrode the metal mesh of the middle plate layer 102.

The thickness of the upper plate layer 101 of the insulating composite plate 100 of the present application is 0.05 mm to 4.0 mm, the thickness of the middle plate layer 102 is 0.05 mm to 0.4 mm, or 0.43 mm to 2 mm, the thickness of the lower plate layer 103 is 0.05 mm to 4.0 mm, or 0.43 mm to

2 mm, and the total thickness of the plate is 0.15 mm to 5.0 mm, or 0.75 mm to 4 mm, or 1.5 mm to

3 mm. The thickness of an insulating composite plate of the present application can meet the customer requirements for the mechanical properties of plates. The Comparative Tracking Index (CTI) of the insulating composite plate 100 of the present application may be 250 volts or higher, and may even reach 600 volts or higher, particularly when the thermoplastic material used for manufacturing the insulating composite plate 100 of the present application is PP, PC or PET. When, for example, PP is selected as a thermoplastic material for manufacturing the insulating composite plate 100 of the present application, the insulating composite plate 100 of the present application can reach a higher CTI. The Relative Thermal Index (RTI) of the insulating composite plate 100 of the present application can reach 90°C or higher.

The insulating composite plate 100 of the present application has the following benefits:

The insulating composite plate 100 of the present application has a good insulating effect because of the upper plate layer 101 and the lower plate layer 103 made of a thermoplastic material. In addition, since the middle plate layer 102 of the insulating composite plate 100 of the present application is a metal mesh, the insulating composite plate 100 of the present application also has the function of electromagnetic shielding.

The inventors have noticed that in applications requiring insulation of components, insulating plates are generally used for the purpose of insulation; in applications requiring electromagnetic shielding, metal plates are generally used for electromagnetic shielding; in applications requiring both insulation and electromagnetic shielding, a combination of insulating plates and metal plates is needed. In the insulating composite plate 100 of the present application, an insulating material and a metal mesh are combined so as to meet the application requirements for both insulation and battery shielding.

In addition, the inventors have observed that, due to the heavy weight of a metal plate, electromagnetic shielding by a metal plate causes an increase in the weight of an apparatus or a device using the metal plate. Consequently, various problems occur, such as an increase in energy consumption of the apparatus or the device. The insulating composite plate 100 of the present application has a relatively small weight because the plate 100 of the present application has the upper plate layer 101 and the lower plate layer 103 made of a thermoplastic material. Therefore, compared with the use of a metal plate for electromagnetic shielding, electromagnetic shielding using the insulating plate 100 of the present application reduces the weight of an apparatus or device, and thus avoids the problems caused when the dead weight of the metal plate is too large, for example, reducing the apparatus or device weight, which in turn reduces energy consumption.

In addition, the upper plate layer 101 and the lower plate layer 103 of the insulating composite plate 100 of the present application are bonded together through the openings of the metal mesh of the middle plate layer 102 in a molten state during the forming process, as if formed integrally. Thus, the upper plate layer 101 and the lower plate layer 103 can be firmly and tightly bonded together for a long time without separation. In addition, there is no gap between the upper plate layer 101, the middle plate layer 102, and the lower plate layer 103. Thus, moisture cannot enter between the upper plate layer 101, the middle plate layer 102, and the lower plate layer 103 to corrode the metal mesh of the middle plate layer 102. Moreover, the metal mesh of the middle plate layer 102 is embedded or at least partially embedded in the surfaces of the upper plate layer 101 and the lower plate layer 103, further strengthening the bonding strength between the layers of the plate 100.

The insulating composite plate 100 of the present application is suitable for use in various applications requiring electromagnetic shielding and insulation. In particular, the insulating composite plate 100 of the present application is particularly suitable for use as a battery pack cover for an electric vehicle due to the benefits described above. At present, global energy and the environment are facing enormous challenges. As a major petroleum consumer and carbon dioxide emitter, the automobile industry needs to undergo revolutionary changes. In order to reduce carbon dioxide emissions, a consensus has been reached on the development of new energy vehicles on a global scale. From a long-term point of view, pure electric drive including pure electric and fuel cell technologies will be the main technical direction of new energy vehicles. In the short term, oil/electric hybrid power and plug-in oil/electric hybrid power will be an important transition route. At present, the research and development hot spots of electric vehicles are mainly the improvement of operating range. The direction of improvement is, on the one hand, from the improvement of battery technology, and on the other hand, from the reduction in the vehicle body weight under the premise of ensuring the safety of vehicles. Since the battery in an electric vehicle emits electromagnetic waves during operation, electromagnetic interference with other electronic components of the vehicle is easily generated and the human body is adversely affected. The current solution is to add a metal cover plate above the battery. However, a metal cover plate is relatively heavy. Therefore, adding a metal cover plate above a vehicle battery increases the weight of the vehicle body, and thus leads to higher vehicle energy consumption, which is not conducive to improving the operating range of the electric vehicle. A battery pack cover for an electric vehicle produced by using the insulating plate 100 of the present application not only enables a battery pack cover to have a good insulating effect but also has the function of electromagnetic shielding. In addition, since a battery pack cover made of the insulating composite plate 100 of the present application has a significantly smaller dead weight compared with a metal plate in the prior art, the vehicle body weight is reduced and thus the vehicle energy consumption is reduced. Therefore, the development expectation of increasing the operating range of electric vehicles is met. Moreover, since the layers of the insulating composite plate 100 of the present application can be firmly and tightly bonded together for a long time without separation, no gap exists between the layers of the plate, so that moisture cannot enter between the layers of the plate to corrode the metal mesh of the middle plate layer 1. Thus, the insulating composite plate 100 of the present application can maintain an excellent electromagnetic shielding effect for a long time.

Figure 6 is a schematic view of a battery pack cover 600 made of the insulating composite plate 100 according to the present application. The battery pack cover 600 is formed in a shape of four walls extending from the peripheral edges for covering the battery pack housing, so that the four walls of the battery pack cover 600 extending from the peripheral edges surround the four walls of the battery pack housing. Figure 7 shows a schematic view of the battery pack cover 600 in Figure 6 covered on the battery pack housing.

Figures 3A and 3B are schematic views of a cast heat press molding process of the plate 100 according to an embodiment of the present application. The cast heat press molding process comprises an extrusion apparatus 301 and a molding apparatus 302. The extrusion apparatus 301 comprises a head die 305, a body 309, and a hopper 307. The hopper 307 is for receiving a thermoplastic material. The head die 305 has an inlet end 352 and an outlet end 351. The body 309 has a body outlet end 321; the body outlet end 321 and the inlet end 352 of the head die 305 are connected by a pipe 330 for conveying a material to the head die 305. The body 309 also has a feed inlet 323 connected to the hopper 307 for receiving a material from the hopper 307. The body 309 is provided with a drive mechanism, for example, a drive screw (not shown). The head die 305 has a suitable width and thickness for accommodating a material transferred from the body 309, and the die cavity of the head die 305 is substantially flat, so that a material transferred from the body can be molded into a flat shape. The molding apparatus 302 has a plurality of rollers 328 for cooling and molding.

The cast heat press molding process shown in Figures. 3 A and 3B is as follows:

As shown in Figure 3A, particles of a first thermoplastic material are added to the hopper 307. The particles of the first thermoplastic material enter the body 309 through the feed inlet of the body 309. The particles of the first thermoplastic material are melted in the body 309 to form a molten state and are mixed uniformly and then, by the drive mechanism of the body, are fed via the pipe 330 to the head die 305 through the inlet end 352 of the head die 305. In the head die 305, the first thermoplastic material in a molten state is molded to form a first plate thermoplastic material 360. The first plate thermoplastic material 360 is output from the outlet end 351 of the head die 305 to the molding roll 328 of the molding apparatus 302.

When the first plate thermoplastic material 360 is fed to the molding roll 328, the metal mesh 102 is unwound from the metal mesh roll 12 so that the unwound metal mesh 102 and the first plate thermoplastic material 360 are in an up-down positional relationship while being conveyed to the molding roll 328 of the molding apparatus 302, successively passing between the molding rolls 328.1 and 328.2 and between the molding rolls 328.2 and 328.3. The molding rolls 388.1, 328.2 and 328.3 apply tensile and compressive forces to the first plate thermoplastic material 360 and the metal mesh 102, so that the metal mesh 102 is embedded or at least partially embedded in the surface of the first plate thermoplastic material 360 to form a press-fitted plate 310. Then, the press-fitted plate 310 is rolled into a press-fitted plate roll. As needed, the metal mesh 102 and the first plate thermoplastic material 360 may pass through a plurality of rollers, or may pass only two rollers.

Next, as shown in Figure 3B, after the first step, the second step of the cast heat press molding process is shown in Figure 3B. Similar to the first step, particles of a second thermoplastic material are added into the body 309 from the hopper 307. The particles of the second thermoplastic material may be the same as or different from the particles of the first thermoplastic material. The particles of the second thermoplastic material enter the body 309 through the feed inlet of the body 309. The particles of the second thermoplastic material are melted in the body 309 to form a molten state and are mixed uniformly and then, by the drive mechanism of the body, are fed via the pipe 330 to the head die 305 through the inlet end 352 of the head die 305. In the head die 305, the second thermoplastic material in a molten state is molded to form a second plate thermoplastic material 380 in a molten state. The second plate thermoplastic material 380 is output from the outlet end 351 of the head die 305 to the molding roll 328 of the molding apparatus 302.

While the second plate thermoplastic material 380 is output from the outlet end 351 of the head die 305 to the molding roll 328 of the molding apparatus 302, the press-fitted plate 310 formed as shown in Figure 3A is unwound from the press-fitted plate roll. Thus, the unwound press-fitted plate 310 and the second plate thermoplastic material 380 are simultaneously conveyed to the molding roll 328 of the molding apparatus 302, successively passing between the molding rolls 328.1 and 328.2 and between the molding rolls 328.2 and 328.3. In the process, one side of the metal mesh 102 of the press-fitted plate 310 faces the second plate thermoplastic material 380. The molding roll 328 applies tensile and compressive forces to the second plate thermoplastic material 380 and the press-fitted plate 310 such that the metal mesh 102 of the press-fitted plate 310 is embedded or at least partially embedded in the second plate thermoplastic material 380. In addition, the second plate thermoplastic material 380 is in a molten state when it exits the outlet end 351 of the head die. Therefore, when the molding roll 328 presses the second plate thermoplastic material 380 and the press-fitted plate 310, the second plate thermoplastic material 380 in a molten state may flow through the openings in the metal mesh 102 to come into contact with the first plate thermoplastic material 360 of the press-fitted plate 310 and solidify after being cooled by the molding roll 328. As a result, the second plate thermoplastic material 380 and the first plate thermoplastic material 360, as if integrally molded, can remain firmly and tightly bonded together over a long period of time. In addition, before the unwinding of the press-fitted plate roll to convey the press-fitted plate 310 or the conveyance of the press-fitted plate 310 to the molding roll 328, as needed, the press-fitted plate 310 may be selectively heated so that the first plate thermoplastic material 360 therein reaches a molten state, thereby achieving a firmer and tighter bonding between the first plate thermoplastic material 360 and the second plate thermoplastic material 380.

By the above-mentioned cast heat press molding process shown in Figures 3A and 3B , the insulating composite plate 100 of the present application is obtained.

In the above-mentioned cast heat press molding process, desired thicknesses of the upper plate layer 101 and the lower plate layer 103 can be obtained by controlling the speed at which the first plate thermoplastic material and the second plate thermoplastic material exit the head die 305 and the rotational speed of the molding roll 328.

Figure 4 shows a co-extrusion process for producing an insulating composite plate according to the present application, the process comprising two extrusion apparatuses and one molding apparatus. As shown in Figure 4, a first extrusion apparatus 301.1 produces the first plate thermoplastic material 360, and a second extrusion apparatus 301.2 produces the second plate thermoplastic material 380; the first plate thermoplastic material 360, the metal mesh 102, and the second plate thermoplastic material 380 are molded together by the molding apparatus 302 to produce the plate 100.

Particles of the first thermoplastic material are added into the body 309.1 through the hopper 307.1. The first thermoplastic material melts in the body 309.1 to form a molten state and, by the drive mechanism of the body 309.1, is fed via the pipe 330.1 to the head die 305.1 through the inlet end 352.1 of the head die 305.1. In the head die 305.1, the first thermoplastic material in a molten state is molded to form a first plate thermoplastic material 360 in a molten state. The second plate thermoplastic material 360 is output from the outlet end 351.1 of the head die 305.1 to the molding roll 328 of the molding apparatus 302. At the same time, particles of the second thermoplastic material are added into the body 309.2 through the hopper 307.2. The particles of the second thermoplastic material can be the same as or different from the particles of the first thermoplastic material. The second thermoplastic material melts in the body 309.2 to form a molten state and, by the drive mechanism of the body 309.2, is fed via the pipe 330.2 to the head die 305.2 through the inlet end 352.2 of the head die 305.2. In the head die 305.2, the second thermoplastic material in a molten state is molded to form a second plate thermoplastic material 380 in a molten state. The second plate thermoplastic material 380 is output from the outlet end 351.2 of the head die 305.2 to the molding roll 328 of the molding apparatus 302.

At the same time, the metal mesh 102 is unwound from the metal mesh roll 12 so that the unwound metal mesh 102, the first plate thermoplastic material 360, and the second plate thermoplastic material 380 are simultaneously conveyed to the molding roll 328 of the molding apparatus 302, successively passing between the molding rolls 328.1 and 328.2 and between the molding rolls 328.2 and 328.3. In this process, the metal mesh 102 is located between the first plate thermoplastic material 360 and the second plate thermoplastic material 380. The molding rolls 328.1, 328.2, and 328.3 apply tensile and compressive forces to the first plate thermoplastic material 360, the second plate thermoplastic material 380, and the metal mesh 102 such that the metal mesh 102 is embedded or at least partially embedded in the surfaces of the first plate thermoplastic material 360 and the second plate thermoplastic material 380. In addition, the first plate thermoplastic material 360 and the second plate thermoplastic material 380 are in a molten state when exiting the outlet ends 351.1 and 351.2 of the head die. Therefore, when the molding roll 328 presses the first plate thermoplastic material 360, the second plate thermoplastic material 380, and the press-fitted plate 310, the first plate thermoplastic material 360 and the second plate thermoplastic material 380 in a molten state may flow through the openings in the metal mesh 102 to come into contact with each other and solidify after being cooled by the molding roll 328. As a result, the second plate thermoplastic material 380 and the first plate thermoplastic material 360, as if integrally molded, can remain firmly and tightly bonded together over a long period of time.

As needed, the metal mesh 102, the first plate thermoplastic material 360, and the second plate thermoplastic material 380 may pass through a plurality of rollers, or may pass through only two rollers.

In the composite plate 100 made by the above-mentioned two processes, the upper plate layer

101 and the lower plate layer 103 are bonded together without using an additional medium (e.g., glue), as if formed integrally. Therefore, the middle plate layer 102, the upper plate layer 101, and the lower plate layer 103 of the metal mesh can be firmly and tightly bonded together for a long time, not prone to separation. In addition, there is no gap between the middle plate layer 102, the upper plate layer 101, and the lower plate layer 103. Thus, moisture cannot enter between the middle plate layer 102, the upper plate layer 101, and the lower plate layer 103 to corrode the metal mesh.

The following are embodiments of composite plate samples produced by cast heat press molding. The materials used in these embodiments were as follows: PP, manufactured by ITW Electronic Components/Products (Shanghai) Co., Ltd. under the trade name Formex GK; the copper mesh was an 80-opening commercial copper mesh, wherein the diameter of the copper wire was 0.1 mm, the spacing of adjacent copper wires was 0.2 mm, the thickness was 0.15 mm, and the copper content was 99.8%.

Embodiment 1

Using the method of cast heat press molding, PP particles were plasticized and molded to obtain an upper plate layer. The thickness of the upper plate layer obtained by molding was 0.13 mm. The upper plate layer obtained by molding and the copper mesh placed between the head die and the roller were cooled and molded at the same time by the roller to obtain a press-fitted plate. The PP particles were then plasticized and molded to obtain a lower plate layer, which was kept 0.76 mm thick. The press-fitted plate of the previously molded upper plate layer and the copper mesh was placed between the head die and the roller, and was rolled, cooled, and molded together with the lower plate layer to obtain an insulating composite plate.

Embodiment 2

Using the method of cast heat press molding, PP particles were plasticized and molded to obtain an upper plate layer. The thickness of the upper plate layer obtained by molding was 0.25 mm. The upper plate layer obtained by molding and the copper mesh placed between the head die and the roller were cooled and molded at the same time by the roller to obtain a press-fitted plate. The PP particles were then plasticized and molded to obtain a lower plate layer, which was kept 2.5 mm thick. The press-fitted plate of the previously molded upper plate layer and the copper mesh was placed between the head die and the roller, and was rolled, cooled, and molded together with the lower plate layer to obtain an insulating composite plate. Embodiment 3

Using the method of cast heat press molding, PP particles were plasticized and molded to obtain an upper plate layer. The thickness of the upper plate layer obtained by molding was 0.43 mm. The upper plate layer obtained by molding and the copper mesh placed between the head die and the roller were cooled and molded at the same time by the roller to obtain a press-fitted plate. The PP particles were then plasticized and molded to obtain a lower plate layer, which was kept 2.5 mm thick. The press-fitted plate of the previously molded upper plate layer and the copper mesh was placed between the head die and the roller, and was rolled, cooled, and molded together with the lower plate layer to obtain an insulating composite plate.

Embodiment 4

Using the method of cast heat press molding, PP particles were plasticized and molded to obtain an upper plate layer. The thickness of the upper plate layer obtained by molding was 0.13 mm. The upper plate layer obtained by molding and the copper mesh placed between the head die and the roller were cooled and molded at the same time by the roller to obtain a press-fitted plate. The PP particles were then plasticized and molded to obtain a lower plate layer, which was kept 0.76 mm thick. The press-fitted plate of the previously molded upper plate layer and the copper mesh was placed between the head die and the roller, and was rolled, cooled, and molded together with the lower plate layer to obtain an insulating composite plate.

The four samples produced were compared to observe their surface effects. In addition, the four samples and aluminum foils were respectively used to wrap self-made battery packs; the battery packs were energized and different frequencies were configured. The electric field intensities outside the battery packs before and after the four samples produced and the aluminum foils were used to wrap the battery packs were tested to obtain the differences in electric field intensity outside the battery packs before and after the four samples produced and the aluminum foils were used to wrap the battery packs. These differences reflected the electromagnetic shielding effects of the four samples produced and the aluminum foils. The following table lists the results of the experiment on the differences in electric field intensity outside the battery packs before and after the four samples produced and the aluminum foils were respectively used to wrap the battery packs at 50 MHz:

layer/mm

Thickness of 2.50 2.50 2.50 0.76

the lower plate

layer/mm

Difference in 28.26 28.33 28.45 28.12 28.21 electric field

intensity

dBuV/m

Plate surface There were There were Very smooth There were

effect obvious folds. slight folds. obvious folds.

The experimental results showed that the four insulating composite plates produced by compounding PP and a copper mesh according to the present invention effectively decreased the electric field intensities outside the wrapped battery packs (see the measured differences in electric field intensity outside the battery packs before and after the battery packs were wrapped); in addition, the electromagnetic shielding effect of the four insulating composite plates produced was similar to that of the aluminum foils (having the same thickness as the intermediate copper mesh of the four insulating composite plates produced). Therefore, an insulating composite plate of the present invention has a good electromagnetic shielding effect. In addition, when the thickness of the upper plate layer of an insulating composite plate of the present invention is greater than 0.43 mm, since in this case the upper plate layer has a large thickness and a high strength, the upper plate layer is not easily deformed when being pressed together with the copper mesh and the lower plate layer. Therefore, an insulating composite plate produced has a good surface effect, smooth and aesthetically pleasing.

While some features of the present invention have been particularly illustrated and described above with reference to specific embodiments, it should be understood that various improvements and alterations may be made by those of ordinary skill in the present art without departing from the spirit and scope of the present invention as defined by the Claims attached.