Plate type heat pipe

Abstract

The utility model relates to a plate type heat pipe which comprises a first heat conducting plate and a second heat conducting plate. The first heat conduction plate is provided with a first side face and a third side face, and a plurality of first working grooves are formed in the first side face. The second heat conducting plate is provided with a second side surface and a fourth side surface, and a plurality of second working grooves are formed in the second side surface; a first capillary structure layer is arranged on the first side surface and the inner wall of the first working groove; a second capillary structure layer is arranged on the second side surface and the inner wall of the second working groove; the first heat-conducting plate is attached to the second heat-conducting plate, the edge of the first heat-conducting plate is connected with the edge of the second heat-conducting plate in a welded mode, a first working cavity is defined by the first working groove and the second side face, and a second working cavity is defined by the second working groove and the first side face. The plate type heat pipe internally contains more working cavities with capillary structure layers, the space in the heat pipe is fully utilized, and compared with a traditional plate type heat pipe with the same size, the area of the capillary structure layers at the evaporation end and the cooling end is increased, and the heat dissipation efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the field of heat pipes, in particular to a plate heat pipe. Background Art

[0002] A heat pipe is a commonly used heat dissipation component for electronic devices. A capillary structure layer and a working medium are arranged inside it. The working process is as follows: the working medium absorbs heat and vaporizes at the evaporation end, and then moves through the inner cavity of the heat pipe to the cooling end. The gaseous working medium liquefies when encountering cold at the cooling end, and then returns to the evaporation end under the action of the capillary structure layer. The working medium circulates, continuously transferring the heat at the evaporation end to the cooling end to achieve heat dissipation at the evaporation end.

[0003] Currently, heat pipes are generally divided into two categories, namely tubular heat pipes and plate heat pipes. The existing plate heat pipes are in a plate shape, with a cavity arranged inside, and a capillary structure layer is arranged on the side wall of the cavity. For specific reference, existing technologies such as CN200910308623.4 - plate heat pipes can be referred to. The forming difficulty of the capillary structure layer of the plate heat pipe is lower, but under the same volume, the evaporation area of the capillary structure layer of the plate heat pipe is smaller than that of the tubular heat pipe, and the heat dissipation efficiency is lower than that of the tubular heat pipe. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is to provide a plate heat pipe with high heat dissipation efficiency.

[0005] To solve the above problems, the technical scheme adopted by the utility model is: a plate heat pipe, comprising a first heat conducting plate and a second heat conducting plate;

[0006] The first heat conducting plate has a first side surface and a third side surface, and a plurality of mutually parallel first working grooves are arranged on the first side surface;

[0007] The second heat conducting plate has a second side surface and a fourth side surface, and a plurality of mutually parallel second working grooves are arranged on the second side surface. The distance between two adjacent second working grooves is the same as the notch width of the first working groove, and the distance between two adjacent first working grooves is the same as the notch width of the second working groove;

[0008] A first capillary structure layer is arranged on the first side surface and the inner wall of the first working groove, and a second capillary structure layer is arranged on the second side surface and the inner wall of the second working groove;

[0009] The first heat conducting plate and the second heat conducting plate are attached, and the edge of the first heat conducting plate is welded to the edge of the second heat conducting plate. The first working groove and the second side surface enclose a first working cavity, and the second working groove and the first side surface enclose a second working cavity.

[0010] Further, a first working fluid injection channel is provided on the first side surface. The first working fluid injection channel is perpendicular to the first working grooves and communicates with all the first working grooves, and one end of the first working fluid injection channel extends to the edge of the first side surface; a second working fluid injection channel is provided on the second side surface. The second working fluid injection channel is perpendicular to the second working grooves and communicates with all the second working grooves, and one end of the second working fluid injection channel extends to the edge of the second side surface; the first working fluid injection channel and the second working fluid injection channel enclose a working fluid injection hole, and the orifice of the working fluid injection hole is closed.

[0011] Further, a third heat conducting plate is further included. The third heat conducting plate has a fifth side surface and a sixth side surface;

[0012] A plurality of mutually parallel third working grooves are provided on the third side surface of the first heat conducting plate, and the third working grooves and the first working grooves are staggered;

[0013] A plurality of mutually parallel fourth working grooves are provided on the fifth side surface. The distance between two adjacent fourth working grooves is equal to the notch width of the third working grooves, and the distance between two adjacent third working grooves is equal to the notch width of the fourth working grooves;

[0014] A third capillary structure layer is provided on the inner wall of the third working grooves and the third side surface, and a fourth capillary structure layer is provided on the inner wall of the fourth working grooves and the fifth side surface;

[0015] The third heat conducting plate is attached to the first heat conducting plate, and the edge of the third heat conducting plate is welded to the edge of the first heat conducting plate. The third working grooves and the fifth side surface enclose a third working chamber, and the fourth working grooves and the third side surface enclose a fourth working chamber.

[0016] Further, welding grooves are provided at the edges of the first heat conducting plate and the second heat conducting plate.

[0017] Further, the first heat conducting plate and the second heat conducting plate are copper plates.

[0018] Further, the first capillary structure layer and the second capillary structure layer are copper powder sintered layers.

[0019] Further, the first working grooves and the second working grooves are semi-circular grooves.

[0020] The beneficial effects of the present utility model are as follows: After the first heat conduction plate and the third heat conduction plate are bonded and welded in the present utility model, the first side surface between two adjacent first working grooves and the second working groove enclose a working cavity, and the second side surface between two adjacent second working grooves and the second working groove enclose a working cavity, so that the heat pipe contains more working cavities with capillary structure layers inside, making full use of the space inside the heat pipe. Compared with the traditional plate heat pipe of the same volume, the area of the capillary structure layer at the evaporation end and the cooling end increases, and the heat dissipation efficiency is improved. Brief Description of the Drawings

[0021] Figure 1 is a schematic cross-sectional view of the heat pipe according to the first embodiment of the present utility model;

[0022] Figure 2 is a schematic view of the first side surface of the first heat conduction plate after being processed through step S2 in the first embodiment;

[0023] Figure 3 is a schematic cross-sectional view of the first heat conduction plate after being processed through step S2 in the first embodiment;

[0024] Figure 4 is a schematic view of the second side surface of the second heat conduction plate after being processed through step S2 in the first embodiment;

[0025] Figure 5 is a schematic cross-sectional view of the second heat conduction plate after being processed through step S2 in the first embodiment;

[0026] Figure 6 is a schematic cross-sectional view of the first heat conduction plate after being processed through step S4 in the first embodiment;

[0027] Figure 7 is a schematic cross-sectional view of the second heat conduction plate after being processed through step S4 in the first embodiment;

[0028] Figure 8 is a schematic cross-sectional view of the heat pipe according to the second embodiment of the present utility model;

[0029] Figure 9 is a schematic view of the third side surface of the first heat conduction plate after being processed through step S2 in the second embodiment;

[0030] Figure 10 is a schematic cross-sectional view of the first heat conduction plate after being processed through step S2 in the second embodiment;

[0031] Figure 11 is a schematic view of the fifth side surface of the third heat conduction plate after being processed through step S2 in the second embodiment;

[0032] Figure 12 is a schematic cross-sectional view of the third heat conduction plate after being processed through step S2 in the second embodiment;

[0033] Figure 13 It is a schematic diagram of the fifth side of the first heat conduction plate after being processed through step S4 in the second embodiment;

[0034] Figure 14 It is a schematic cross-sectional view of the third heat conduction plate after being processed through step S4 in the second embodiment;

[0035] Reference numerals: 1—the first heat conduction plate; 2—the second heat conduction plate; 3—the first side; 4—the first working groove; 5—the second side; 6—the second working groove; 7—the first capillary structure layer; 8—the second capillary structure layer; 9—the first working fluid injection channel; 10—the second working fluid injection channel; 11—the third side; 12—the fourth side; 13—the third heat conduction plate; 14—the fifth side; 15—the sixth side; 16—the third working groove; 17—the fourth working groove; 18—the third capillary structure layer; 19—the fourth capillary structure layer; 30—the welding groove. Detailed implementation manners

[0036] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0037] Embodiment 1

[0038] The plate heat pipe of the present embodiment, as Figure 1 shown, includes a first heat conduction plate 1 and a second heat conduction plate 2. The first heat conduction plate 1 and the second heat conduction plate 2 are made of plates with high thermal conductivity, such as stainless steel, etc., and preferably made of copper plates, and the shape is rectangular. The first heat conduction plate 1 has a first side 3 and a third side 11, and the second heat conduction plate 2 has a second side 5 and a fourth side 12. The two sides of the first heat conduction plate 1 are the first side 3 and the third side 11 respectively, and the two sides of the second heat conduction plate 2 are the second side 5 and the fourth side 12 respectively.

[0039] A plurality of mutually parallel first working grooves 4 are provided on the first side 3; there is a spacing between the two ends of the first working groove 4 and the ends of the first heat conduction plate 1, that is, the two ends of the first working groove 4 do not extend to the ends of the first heat conduction plate 1. A plurality of mutually parallel second working grooves 6 are provided on the second side 5, and there is a spacing between the two ends of the second working groove 6 and the ends of the second heat conduction plate 2, and the two ends of the second working groove 6 do not extend to the ends of the second heat conduction plate 2. The first heat conduction plate 1 and the second heat conduction plate 2 have the same thickness, the first working groove 4 and the second working groove 6 have the same depth, and the depth of the first working groove 4 is about 2 / 3 of the thickness of the first heat conduction plate 1, making full use of the internal space of the first heat conduction plate 1 while ensuring the strength of the heat pipe.

[0040] The spacing between adjacent first working grooves 4 is the same, and the spacing between adjacent second working grooves 6 is also the same. The notch widths of all the first working grooves 4 are the same, and the notch widths of all the second working grooves 6 are also the same. The notch width of the first working groove 4 is the same as that of the second working groove 6. The spacing between adjacent second working grooves 6 is the same as the notch width of the first working groove 4, and the spacing between adjacent first working grooves 4 is the same as the notch width of the second working groove 6.

[0041] A first capillary structure layer 7 is provided on the first side surface 3 and the inner wall of the first working groove 4, and a second capillary structure layer 8 is provided on the second side surface 5 and the inner wall of the second working groove 6. The first capillary structure layer 7 and the second capillary structure layer 8 are used to promote the reflux of the working fluid at the cooling end. Specifically, a copper powder sintered layer can be adopted, that is, copper powder is first sprayed and then sintered to form a capillary structure layer.

[0042] The first heat conducting plate 1 and the second heat conducting plate 2 are attached, and the edges of the first heat conducting plate 1 and the second heat conducting plate 2 are welded. The first working groove 4 and the second side surface 5 enclose a first working chamber, and the second working groove 6 and the first side surface 3 enclose a second working chamber. A working fluid (not shown in the figure) is filled in the first working chamber and the second working chamber. The working fluid can be a common working fluid such as water.

[0043] For the heat pipe of this embodiment, one end of the first working chamber and the second working chamber serves as the evaporation end, which is installed near the heat source of the electronic device or contacts the heat source of the electronic device (such as components like the main board), and the other end serves as the cooling end, away from the heat source of the electronic device, so as to dissipate heat from the electronic device.

[0044] The heat pipe of the present utility model contains multiple first working chambers and second working chambers inside. The area of the capillary structure layer is larger, making the evaporation area of the working fluid larger and the heat absorption efficiency higher, thus the heat dissipation effect is better. In addition, when preparing the heat pipe of the present utility model, copper powder can be sprayed on the first side surface 3, the inner wall of the first working groove 4, the second side surface 5, and the inner wall of the second working groove 6. The process difficulty is relatively low, and the side surfaces of the first heat conducting plate 1 and the second heat conducting plate 2 can be sprayed comprehensively, rather than only being sprayed at local positions, further reducing the spraying difficulty.

[0045] The specific preparation steps of the plate heat pipe of this embodiment are as follows:

[0046] S1. Obtain the first heat conducting plate 1 and the second heat conducting plate 2. The first heat conducting plate 1 and the second heat conducting plate 2 are made of materials with high thermal conductivity, preferably copper plates. The first heat conducting plate 1 and the second heat conducting plate 2 are rectangular plates. The first heat conducting plate 1 and the second heat conducting plate 2 with the same size are obtained by cutting and blanking, and the edges of the first heat conducting plate 1 and the second heat conducting plate 2 are subjected to capillary treatment, and then cleaned. The thickness, length and width of the first heat conducting plate 1 and the second heat conducting plate 2 are flexibly designed according to the actual application environment.

[0047] S2. The first heat conducting plate 1 has a first side 3 and a third side 11. A plurality of mutually parallel first working grooves 4 are machined on the first side 3. There is a spacing between the two ends of the first working groove 4 and the end of the first heat conducting plate 1, as Figure 2 and Figure 3 shown. The second heat conducting plate 2 has a second side 5 and a fourth side 12. A plurality of mutually parallel second working grooves 6 are machined on the second side 5 of the second heat conducting plate 2. There is a spacing between the two ends of the second working groove 6 and the end of the second heat conducting plate 2, as Figure 4 and Figure 5 shown. The first heat conducting plate 1 and the second heat conducting plate 2 can be milled by a lathe such as a milling machine or a machining center. The depth of the first working groove 4 is about 2 / 3 of the thickness of the first heat conducting plate 1, and the depth of the second working groove 6 is about 2 / 3 of the thickness of the second heat conducting plate 2.

[0048] The spacing between two adjacent second working grooves 6 is the same as the notch width of the first working groove 4, and the spacing between two adjacent first working grooves 4 is the same as the notch width of the second working groove 6, so that the first side 3 between two adjacent first working grooves 4 and the second working groove 6 can enclose a first working cavity, and the second side 5 between two adjacent second working grooves 6 and the first working groove 4 can enclose a second working cavity, which can make full use of the internal space of the heat pipe, increase the number of working cavities, increase the area of the capillary structure layer, and improve the heat dissipation efficiency.

[0049] S3. Spray a first capillary structure forming layer on the inner wall of the first working groove 4 and the first side 3, and spray a second capillary structure forming layer on the inner wall of the second working groove 6 and the second side 5.

[0050] Since the first heat conducting plate 1 and the second heat conducting plate 2 are plate-shaped, both the first working groove 4 and the second working groove 6 are in an open space. The first capillary structure forming layer and the second capillary structure forming layer are obtained by spraying. The first capillary structure forming layer on the inner wall of the first working groove 4 and the first side surface 3 is formed simultaneously, and the first capillary structure forming layer on the second working groove 6 and the second side surface 5 is formed simultaneously, with high spraying efficiency. Compared with traditional heat pipes, there is no need to fill copper powder into a narrow space, the spraying process has low difficulty and high controllability, and the thickness uniformity of the first capillary structure forming layer and the second capillary structure forming layer is higher. After sintering, a first capillary structure layer and a second capillary structure layer with uniform thickness can be obtained. In addition, during spraying, the entire first side surface 3 and the second side surface 5 can be sprayed without fixed-point spraying, further reducing the difficulty of the spraying process.

[0051] S4. Sinter the first heat conducting plate 1 and the second heat conducting plate 2. The first capillary structure forming layer forms the first capillary structure layer 7, and the second capillary structure forming layer forms the second capillary structure layer 8. The cross-section of the sintered first heat conducting plate 1 is as Figure 6 shown, and the cross-section of the sintered second heat conducting plate 2 is as Figure 7 shown.

[0052] S5. Bond the first heat conducting plate 1 and the second heat conducting plate 2, ensuring that the first working groove 4 is aligned with the second side surface 5 on one side of the second working groove 6, the second working groove 6 is aligned with the first side surface 3 on one side of the first working groove 4, and weld the edges of the first heat conducting plate 1 and the second heat conducting plate 2 together. After the edges of the first heat conducting plate 1 and the second heat conducting plate 2 are welded together, the first heat conducting plate 1 and the second heat conducting plate 2 form a heat pipe.

[0053] S6. Inject a working fluid into the first working groove 4 and the second working groove 6. The working fluid can be a common working fluid such as water.

[0054] To facilitate injecting the working fluid into the first working groove 4 and the second working groove 6, a first working fluid injection channel 9 is provided on the first side surface 3. The first working fluid injection channel 9 is perpendicular to the first working groove 4 and communicates with all the first working grooves 4, and one end of the first working fluid injection channel 9 extends to the edge of the first side surface 3; a second working fluid injection channel 10 is provided on the second side surface 5. The second working fluid injection channel 10 is perpendicular to the second working groove 6 and communicates with all the second working grooves 6, and one end of the second working fluid injection channel 10 extends to the edge of the second side surface 5; the first working fluid injection channel 9 and the second working fluid injection channel 10 enclose a working fluid injection hole, and the orifice of the working fluid injection hole is closed.

[0055] After machining the first working groove 4, a first working fluid injection channel 9 perpendicular to the first working groove 4 and communicating with all the first working grooves 4 is machined at one end of the first working groove 4, and one end of the first working fluid injection channel 9 extends to the side of the first heat conducting plate 1. After machining the second working groove 6, a second working fluid injection channel 10 perpendicular to the second working groove 6 and communicating with all the second working grooves 6 is machined at one end of the second working groove 6, and one end of the second working fluid injection channel 10 extends to the side of the second heat conducting plate 2. The first working fluid injection channel 9 can connect all the first working grooves 4, and the second working fluid injection channel 10 can connect all the second working grooves 6. The first working fluid injection channel 9 and the second working fluid injection channel 10 can be grooves with a semi-circular cross-section.

[0056] The first working fluid injection channel 9 and the second working fluid injection channel 10 can be machined in step S2 by milling, or can be machined after step S4 and before step S5. Preferably, they are machined in step S2. In subsequent steps, a capillary structure layer can also be formed on the inner walls of the first working fluid injection channel 9 and the second working fluid injection channel 10.

[0057] After the first heat conducting plate 1 and the second heat conducting plate 2 are bonded, the first working fluid injection channel 9 and the second working fluid injection channel 10 enclose a working fluid injection hole. After the first heat conducting plate 1 and the second heat conducting plate 2 are welded, working fluid is injected into the first working groove 4 and the second working groove 6. Vacuum is drawn through the working fluid injection hole and working fluid is injected. After the working fluid injection is completed, the orifice of the working fluid injection hole is closed. Specifically, a copper plug can be set at the orifice of the working fluid injection hole, and the copper plug is welded and connected to the inner wall of the working fluid injection hole, so as to completely close the orifice of the working fluid injection hole.

[0058] The first working groove 4 and the second working groove 6 can be groove bodies with a rectangular cross-section. Preferably, the first working groove 4 and the second working groove 6 are semi-circular grooves. In step S3, when spraying the capillary structure forming layer, the capillary structure forming layer can more evenly cover the inner walls of the first working groove 4 and the second working groove 6, reducing the spraying difficulty.

[0059] In step S3, the spraying process of the first capillary structure forming layer and the second capillary structure forming layer includes: first spraying an adhesive layer, and then spraying a copper powder layer on the surface of the adhesive. The adhesive plays a bonding role, enabling the copper powder to be stably held on the first heat conducting plate 1 and the second heat conducting plate 2. The adhesive can use existing metal bonding adhesives.

[0060] In step S4, a sintering furnace is used to sinter the first heat conducting plate 1 and the third heat conducting plate 13. When sintering, an inert gas and a reducing gas are continuously introduced into the sintering furnace. During sintering, the adhesive volatilizes and decomposes to produce gaseous substances. Therefore, an inert gas and a reducing gas are continuously introduced into the sintering furnace to promote the discharge of the gas generated by the decomposition of the adhesive and prevent the copper powder from being oxidized.

[0061] To ensure the stable connection between the first heat conducting plate 1 and the second heat conducting plate 2 and the tightness of the welding joint, welding grooves 30 are provided at the edges of the first heat conducting plate 1 and the second heat conducting plate 2. Before step S5, specifically, after step S4, the welding grooves 30 are machined at the edges of the first side 3 and the second side 5; in step S5, the welding grooves 30 are filled with welds.

[0062] Embodiment 2

[0063] The cross-section of the plate heat pipe in this embodiment is as Figure 8 shown. On the basis of Embodiment 1, a third heat conducting plate 13 is added. The third heat conducting plate 13 has a fifth side 14 and a sixth side 15;

[0064] On the third side 11 of the first heat conducting plate 1, a plurality of mutually parallel third working grooves 16 are provided, and the third working grooves 16 are staggered with the first working grooves 4;

[0065] On the fifth side 14, a plurality of mutually parallel fourth working grooves 17 are provided. The distance between two adjacent fourth working grooves 17 is equal to the notch width of the third working grooves 16, and the distance between two adjacent third working grooves 16 is equal to the notch width of the fourth working grooves 17;

[0066] On the inner wall of the third working grooves 16 and the third side 11, a third capillary structure layer 18 is provided. On the inner wall of the fourth working grooves 17 and the fifth side 14, a fourth capillary structure layer 19 is provided;

[0067] The third heat conducting plate 13 is attached to the first heat conducting plate 1, and the edge of the third heat conducting plate 13 is welded to the edge of the first heat conducting plate 1. The third working grooves 16 and the fifth side 14 enclose a third working chamber, and the fourth working grooves 17 and the third side 11 enclose a fourth working chamber. A working medium is provided in the third working chamber and the fourth working chamber.

[0068] In the preparation process of the heat pipe in this embodiment, on the basis of Embodiment 1, the following processes are added to each step:

[0069] In step S1, the third heat conducting plate 13 is obtained. The third heat conducting plate 13 has a fifth side 14 and a sixth side 15.

[0070] In step S2, a plurality of mutually parallel third working grooves 16 are machined on the third side 11 of the first heat conducting plate 1. The third working grooves 16 are staggered with the first working grooves 4, and there is a distance between the two ends of the third working grooves 16 and the ends of the first heat conducting plate 1, as Figure 13 and Figure 14As shown in the figure. A plurality of mutually parallel fourth working grooves 17 are machined on the fifth side surface 14 of the third heat conducting plate 13. There is a spacing between the two ends of the fourth working groove 17 and the end of the third heat conducting plate 13. The spacing between two adjacent fourth working grooves 17 is equal to the notch width of the third working groove 16, and the spacing between two adjacent third working grooves 16 is equal to the notch width of the fourth working groove 17.

[0071] In step S3, a third capillary structure forming layer is sprayed on the inner wall of the third working groove 16 and the third side surface 11, and a fourth capillary structure forming layer is sprayed on the inner wall of the fourth working groove 17 and the fifth side surface 14.

[0072] In step S4, the first heat conducting plate 1 and the third heat conducting plate 13 are sintered. The third capillary structure forming layer forms a third capillary structure layer 18, and the fourth capillary structure forming layer forms a fourth capillary structure layer 19.

[0073] In step S5, the third heat conducting plate 13 is attached to the first heat conducting plate 1, ensuring that the fourth working groove 17 is aligned with the third side surface 11 on one side of the third working groove 16, the third working groove 16 is aligned with the fifth side surface 14 on one side of the fourth working groove 17, and the edges of the third heat conducting plate 13 and the first heat conducting plate 1 are welded into one body.

[0074] In step S6, a working medium is injected into the third working groove 16 and the fourth working groove 17.

[0075] The heat pipe of this embodiment has a three-layer structure, with more internal working cavities, further improving the utilization rate of the internal space of the heat pipe and having a higher heat dissipation efficiency.

[0076] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Plate heat pipe, characterized in that: It includes a first heat conducting plate (1) and a second heat conducting plate (2); The first heat conducting plate (1) has a first side surface (3) and a third side surface (11), and a plurality of mutually parallel first working grooves (4) are arranged on the first side surface (3); The second heat conducting plate (2) has a second side surface (5) and a fourth side surface (12), and a plurality of mutually parallel second working grooves (6) are arranged on the second side surface (5). The distance between two adjacent second working grooves (6) is the same as the notch width of the first working groove (4), and the distance between two adjacent first working grooves (4) is the same as the notch width of the second working groove (6); A first capillary structure layer (7) is arranged on the first side surface (3) and the inner wall of the first working groove (4), and a second capillary structure layer (8) is arranged on the second side surface (5) and the inner wall of the second working groove (6); The first heat conducting plate (1) and the second heat conducting plate (2) are attached, and the edge of the first heat conducting plate (1) is welded to the edge of the second heat conducting plate (2). The first working groove (4) and the second side surface (5) enclose a first working cavity, and the second working groove (6) and the first side surface (3) enclose a second working cavity.

2. The plate heat pipe according to claim 1, characterized in that: A first working medium injection channel (9) is arranged on the first side surface (3). The first working medium injection channel (9) is perpendicular to the first working groove (4) and communicates with all the first working grooves (4), and one end of the first working medium injection channel (9) extends to the edge of the first side surface (3); a second working medium injection channel (10) is arranged on the second side surface (5). The second working medium injection channel (10) is perpendicular to the second working groove (6) and communicates with all the second working grooves (6), and one end of the second working medium injection channel (10) extends to the edge of the second side surface (5); the first working medium injection channel (9) and the second working medium injection channel (10) enclose a working medium injection hole, and the orifice of the working medium injection hole is closed.

3. The plate heat pipe according to claim 1, characterized in that: It further includes a third heat conducting plate (13), and the third heat conducting plate (13) has a fifth side surface (14) and a sixth side surface (15); A plurality of mutually parallel third working grooves (16) are arranged on the third side surface (11) of the first heat conducting plate (1), and the third working grooves (16) are staggered with the first working grooves (4); A plurality of mutually parallel fourth working grooves (17) are arranged on the fifth side surface (14). The distance between two adjacent fourth working grooves (17) is equal to the notch width of the third working groove (16), and the distance between two adjacent third working grooves (16) is equal to the notch width of the fourth working groove (17); A third capillary structure layer (18) is arranged on the inner wall of the third working groove (16) and the third side surface (11), and a fourth capillary structure layer (19) is arranged on the inner wall of the fourth working groove (17) and the fifth side surface (14); The third heat conducting plate (13) is attached to the first heat conducting plate (1), and the edges of the third heat conducting plate (13) are welded to the edges of the first heat conducting plate (1). The third working groove (16) and the fifth side surface (14) enclose a third working cavity, and the fourth working groove (17) and the third side surface (11) enclose a fourth working cavity.

4. The plate heat pipe according to claim 1, characterized in that: Welding grooves (30) are provided at the edges of the first heat conducting plate (1) and the second heat conducting plate (2).

5. The plate heat pipe according to claim 1, characterized in that: The first heat conducting plate (1) and the second heat conducting plate (2) are copper plates.

6. The plate heat pipe according to claim 1, characterized in that: The first capillary structure layer (7) and the second capillary structure layer (8) are copper powder sintered layers.

7. The plate heat pipe according to claim 1, wherein: The first working groove (4) and the second working groove (6) are semi-circular grooves.

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