Thermally conductive overmold and method of processing a thermally conductive portion thereof

Abstract

The application provides a heat-conducting upper plastic and a processing method of a heat-conducting part of the upper plastic. The heat-conducting upper plastic comprises a plastic part and a heat-conducting part. The plastic part is in a cylindrical shape with an open upper end, and the lower end of the plastic part is provided with a through mounting hole. The heat-conducting part is matched with the mounting hole and is connected to the mounting hole. The heat-conducting part can prevent heat accumulation on the upper plastic. The processing method of the heat-conducting part comprises the following steps: A, green body preparation; B, primary sintering; C, secondary sintering; and D, hot isostatic pressing. The heat-conducting upper plastic has good heat dissipation performance, and the processing method can improve the quality of the finished heat-conducting part.

Description

Technical Field

[0001] This invention relates to the field of mechanical technology, and more specifically to a method for processing thermally conductive plastic substrates and their thermally conductive components. Background Technology

[0002] The plastic coating on the battery top cover serves to insulate, position, protect against corrosion, reinforce, and conduct heat between the cover and the rivet blocks. Therefore, the plastic coating needs not only good mechanical strength and heat resistance, but also excellent thermal conductivity to quickly dissipate heat generated during equipment operation, preventing heat buildup that could lead to performance degradation and shortened lifespan.

[0003] Currently, commercially available thermally conductive top plastics typically use either PA66 or LCP plastics. It's clear that the inherent properties of these materials limit their thermal conductivity. Ultimately, heat buildup occurs at the top plastic area, and after prolonged use, the top plastic fails, directly impacting the stability and safety of the battery top cover. Summary of the Invention

[0004] The first objective of this invention is to address the aforementioned problems in the existing technology by providing a thermally conductive top plastic with good thermal conductivity and a compact structure.

[0005] A second objective of this invention is to provide a processing method for preparing the thermally conductive portion in the aforementioned thermally conductive plastic.

[0006] To achieve the above objectives, the first objective of this invention can be achieved through the following technical solution:

[0007] A thermally conductive upper plastic part includes a plastic part and a thermally conductive part, characterized in that the plastic part is cylindrical and open at the upper end, the lower end of the plastic part has a through mounting hole, the thermally conductive part matches the mounting hole and is connected to the mounting hole, and the thermally conductive part can prevent heat from accumulating on the upper plastic part.

[0008] The heat-conducting component comprises, by weight ratio:

[0009] Alumina (AL2O3) 85-91 parts

[0010] Zirconium oxide (ZrO2) 8.5-11 parts

[0011] Yttrium trioxide (Y2O3) 0.4–0.7 parts.

[0012] In the aforementioned thermally conductive plastic, the thermally conductive part comprises, by weight percentage, the following components:

[0013] Alumina (AL2O3) 89.7 parts

[0014] Zirconium oxide (ZrO2) 9.38 parts

[0015] 0.52 parts of yttrium trioxide (Y2O3).

[0016] In the above-mentioned thermally conductive plastic, the thermally conductive part is either PPS plastic or thermally conductive silicone.

[0017] In the above-mentioned thermally conductive plastic, the plastic part is either PPS plastic or LCP plastic, and the working temperature of the plastic part is -80℃ to 600℃.

[0018] In the aforementioned thermally conductive plastic, the diameter of the mounting hole is larger than the size of the thermally conductive part, and when the plastic part is deformed by force, the inner edge of the mounting hole can abut against the outer edge of the thermally conductive part.

[0019] To achieve the above objectives, the second objective of this invention can be achieved through the following technical solution:

[0020] A method for processing a heat-conducting part, characterized by comprising the following steps:

[0021] A. Green body preparation: The heat-conducting components in a set ratio are thoroughly mixed to obtain the material. The material is then mixed with water at a weight ratio of 1:0.5 and a sheet-like green body is prepared.

[0022] B. Single sintering: High-temperature short-time sintering at 1500-1560℃ (3-10 min) is used to quickly achieve densification of the green body, while avoiding excessive growth of ZrO2 grains and instability of the tetragonal phase.

[0023] C. Secondary sintering: The billet after primary sintering is subjected to long-term sintering at 1400-1450℃ for 2-5 hours to eliminate thermal stress and phase transformation stress and promote uniform distribution of yttrium oxide.

[0024] D. Hot isostatic pressing: The billet after secondary sintering is subjected to a mild process of 1400-1480℃, 160-180 MPa, and 1-2 h to ensure complete densification while maintaining the tetragonal ZrO2 phase content, ultimately ensuring the high toughness and high strength of the thermally conductive part of the finished product.

[0025] In the above-mentioned thermally conductive plastic, after step B is completed, it is converted into secondary sintering at a cooling rate of 8-10℃ / min to reduce thermal shock and phase transformation cracks.

[0026] In the above-described processing method for the heat-conducting part, step D is performed in an inert gas environment.

[0027] In the above-described processing method for the heat-conducting part, the inert gas in step D is argon.

[0028] In the above-described processing method for the heat-conducting part, the heat-conducting part undergoes surface treatment after step D.

[0029] Compared with existing technologies, the heat-conducting part in the upper plastic of this thermally conductive type can effectively avoid heat accumulation at the upper plastic area, thus having a better heat dissipation effect, which indirectly improves the stability and safety of the battery top cover.

[0030] Compared to pure alumina, high-zirconium ZTA, and 96% alumina ceramics, the core advantage of this thermal conductive part formulation lies in its excellent engineering balance between cost, hardness, toughness, and stability, making it a "high-performance, high-toughness" ZTA.

[0031] Al2O3 (89.7%, main phase) provides the finished thermally conductive part with high hardness (≈16–18 GPa), high wear resistance, high temperature resistance, acid and alkali resistance, low cost, and low density. It ensures the overall rigidity, thermal conductivity, and high-temperature dimensional stability of the thermally conductive part.

[0032] The ZrO2 content (9.38%, toughening phase) is in the low zirconium range (5%–15%), which is just enough to effectively toughen the material without significantly reducing hardness and wear resistance. Fine particles are uniformly dispersed in Al2O3 to achieve stress-induced phase transformation toughening.

[0033] A trace amount of Y2O3 (0.52%, stabilizer) enters the ZrO2 lattice to stabilize the tetragonal phase to room temperature, ensuring that phase transformation toughening can be effectively triggered. Around 0.5% is a stable dosage: sufficiently stable, does not introduce excessive impurities, and does not significantly increase costs.

[0034] Specifically, the finished thermally conductive part has the following characteristics:

[0035] 1. Significantly improved toughness (50%–100% stronger than pure Al2O3)

[0036] Pure Al2O3: Fracture toughness ≈ 3–4 MPa·m¹ / ²

[0037] Thermal conductivity of this part: ≈ 5–6 MPa·m¹ / ²

[0038] The thermally conductive part exhibits significantly improved resistance to impact, chipping, cracking, and thermal shock, making it suitable for dynamic loads, vibrations, and temperature fluctuations.

[0039] 2. Hardness and wear resistance are close to those of pure alumina (far superior to high-zirconium ZTA).

[0040] Vickers hardness: ≈ 1600–1800 HV

[0041] Wear resistance: Slightly better or comparable to pure Al2O3 (hardness + toughness synergistic wear resistance)

[0042] 3. High strength and good reliability

[0043] Flexural strength: ≈ 450–600 MPa (pure Al2O3: 300–400 MPa)

[0044] 4. Excellent thermal and chemical stability

[0045] Its coefficient of thermal expansion and thermal conductivity are close to those of pure Al2O3.

[0046] It is resistant to thermal shock, has low deformation, and is suitable for high-temperature / rapid thermal cycling.

[0047] Its resistance to acids and alkalis, oxidation, and chemical corrosion is comparable to that of pure Al2O3.

[0048] 5. Significant cost advantage (far lower than pure ZrO2 and high-zirconium ZTA)

[0049] The main component is Al2O3 (which is inexpensive), with small amounts of ZrO2 and Y2O2. The sintering temperature and process difficulty are close to those of ordinary Al2O3, making it easy to mass-produce and with a high yield.

[0050] 6. Moderate density, easy to process

[0051] Density ≈ 4.1–4.3 g / cm³ (lower than pure ZrO2)

[0052] It has good rigidity, is not easily deformed, and can be precision machined (high dimensional accuracy and good surface finish).

[0053] Meanwhile, the thermal conductive part has achieved a targeted breakthrough in addressing the technical challenges of composite sintering of alumina, zirconium oxide, and yttrium oxide:

[0054] 1. Solved the problem of unstable crystal structure between components: By optimizing the component ratio of the thermally conductive part, the yttrium oxide (Y2O3) is controlled at 0.4-0.7 parts (optimal 0.52 parts). This ratio is the optimal part stability range of zirconium oxide (ZrO2). It can effectively stabilize the tetragonal phase of zirconium oxide and prevent irreversible phase transformation during sintering, which can lead to ceramic cracking and pulverization. At the same time, it can retain the phase transformation toughening effect of zirconium oxide. With the addition of 81-85 parts of alumina (Al2O3), a balance of "high thermal conductivity + high toughness" is achieved, which solves the problems of crystal structure instability and insufficient toughness caused by improper addition of yttrium oxide in the traditional ratio.

[0055] 2. Resolves the contradiction between sintering process and component characteristics: A three-stage sintering process of "one-time high-temperature short-time sintering + two-time low-temperature long-time sintering + hot isostatic pressing" is adopted to precisely match the component characteristics of alumina, zirconium oxide, and yttrium oxide. The first sintering (1500-1560℃, 3-10min) quickly achieves densification of the green body, avoiding grain coarsening of zirconium oxide under prolonged high temperature and instability failure of yttrium oxide. The second sintering (1400-1450℃, 2-5h) eliminates thermal stress and phase transformation stress, promotes uniform diffusion of yttrium oxide, and further improves the degree of densification. Hot isostatic pressing (1400-1480℃, 160-180MPa, 1-2h) achieves complete densification under mild conditions, maintains the tetragonal phase content of zirconium oxide, and completely solves the core contradiction that "alumina needs high temperature and long firing, while zirconium oxide and yttrium oxide are afraid of high temperature and long firing," which greatly improves the preparation yield and performance stability of the thermally conductive part.

[0056] 3. Solved the problems of impurity phase formation and excessive internal stress during sintering: Argon gas is used as an inert protective atmosphere during hot isostatic pressing, which can effectively isolate air and prevent zirconium oxide and yttrium oxide from reacting with oxygen and nitrogen to form impurity phases, thus avoiding ceramic embrittlement and cracking; at the same time, the cooling rate after the first sintering is controlled at 8-10℃ / min to reduce thermal shock and phase transformation cracks, further reduce internal stress, and ensure the structural integrity of the heat-conducting part.

[0057] 4. Improved connection stability between the heat-conducting part and the plastic part: The diameter of the mounting hole is larger than that of the heat-conducting part. When the plastic part is subjected to force or heat and deforms, the inner edge of the mounting hole can tightly abut against the outer edge of the heat-conducting part, avoiding stress concentration that could cause the heat-conducting part to fall off or break. At the same time, the plastic part is made of PPS or LCP plastic with a working temperature of -80℃ to 600℃, which matches the high temperature resistance of the heat-conducting part, improving the overall heat resistance and service life of the upper plastic part.

[0058] 5. Excellent thermal conductivity and balanced overall performance: The thermally conductive part is mainly composed of alumina, which ensures good thermal conductivity. Combined with the optimized ratio of zirconium oxide and yttrium oxide, the thermally conductive part also has the characteristics of high toughness, high strength, high temperature resistance and excellent insulation. It is suitable for the use of high-end electronic equipment and mechanical equipment, and solves the problems of single performance and poor stability of existing thermally conductive plastic thermally conductive parts. Attached Figure Description

[0059] Figure 1 These are thermal imaging photos of PA66 plastic material.

[0060] Figure 2 It uses thermal imaging data of the plastic on the ceramic heat-conducting part.

[0061] Figure 3It uses thermal imaging data of the plastic on the PPS thermal conductive part.

[0062] Figure 4 This is thermal imaging data of the plastic on the thermally conductive part of this thermally conductive silicone.

[0063] Figure 5 This is a schematic diagram of the three-dimensional structure of the plastic.

[0064] Figure 6 This is a cross-sectional structural diagram of the plastic material.

[0065] In the diagram, 1 is the plastic part; 2 is the heat-conducting part; and 3 is the mounting hole. Detailed Implementation

[0066] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention.

[0067] Example 1

[0068] This thermally conductive upper plastic part includes a plastic part 1 and a thermally conductive part 2. The plastic part 1 is made of PPS plastic and has a working temperature of 240℃. The plastic part 1 is cylindrical with an open top and a through mounting hole 3 at the bottom. The diameter of the mounting hole 3 is 0.5mm larger than that of the thermally conductive part 2. See [reference needed]. Figure 5 and Figure 6 As shown.

[0069] The heat-conducting part 2 can prevent heat from accumulating on the upper plastic part.

[0070] The thermally conductive component comprises, by weight, 89.7 parts of alumina (Al2O3), 9.38 parts of zirconium oxide (ZrO2), and 0.52 parts of yttrium oxide (Y2O3);

[0071] The processing method for the heat-conducting part includes the following steps:

[0072] A. Green body preparation: The alumina, zirconium oxide and yttrium oxide components in the above weight ratio are put into a mixing device and mixed thoroughly to obtain a uniform material; the material is mixed with water at a weight ratio of 1:0.5, stirred evenly, and then a sheet-shaped green body is prepared by pressing molding process. The thickness of the green body is set to 2mm according to the actual use requirements.

[0073] B. Single sintering: The green blank is placed in a sintering furnace and heated to 550°C at a heating rate of 0.8°C / min, and then rapidly heated to 1530°C at a heating rate of 10°C / min. It is held for 6 minutes to quickly achieve densification of the green blank, while avoiding excessive growth of ZrO2 grains and instability of the tetragonal phase.

[0074] C. Secondary sintering: After the first sintering is completed, the temperature is lowered to 1420℃ at a cooling rate of 9℃ / min and held for 3 hours to eliminate thermal stress and phase transformation stress, promote the uniform distribution of yttrium oxide, and further improve the densification of ceramics.

[0075] D. Hot Isostatic Pressing: The billet after secondary sintering is placed in a hot isostatic pressing equipment, and high-purity argon gas (purity ≥99.999%) is introduced as an inert protective atmosphere. The pressure is first increased to 50MPa, and then the temperature is raised to 1450℃, so that the pressure increases to 170MPa. The temperature is held for 1.5h to ensure complete densification while maintaining the content of ZrO2 tetragonal phase.

[0076] Depending on the specific circumstances, nitrogen can also be used instead of argon.

[0077] E. Surface treatment: After hot isostatic pressing, the surface of the heat-conducting part is ground and polished to remove surface impurities and burrs, so that the surface roughness of the heat-conducting part meets the installation requirements.

[0078] F. Assembly: Install the treated heat-conducting part into the mounting hole of the plastic part. Since the diameter of the mounting hole is larger than the size of the heat-conducting part, when the plastic part is deformed by force, the inner edge of the mounting hole can tightly abut against the outer edge of the heat-conducting part, thus achieving a stable connection between the heat-conducting part and the plastic part.

[0079] Zirconia acts like a "buffer" for alumina, solving the problem of traditional ceramics being "too hard but easily broken".

[0080] Trace amounts of yttrium oxide enter the zirconium oxide lattice, stabilizing the tetragonal phase to room temperature and ensuring that the phase transformation toughening energy can be effectively triggered. Yttrium oxide acts as a "stabilizer".

[0081] The parameters of the finished thermally conductive part in this embodiment are as follows compared to those of 96% alumina ceramic:

[0082] I. Mechanical Properties:

[0083] II. Electrical Properties

[0084] The dielectric constant of the thermally conductive part is 12.35 and the dielectric loss is 0.089% at 1MHz.

[0085] Conversely, 96% alumina ceramic has a dielectric constant of 9.4 and a dielectric loss of 0.0002% at 1MHz.

[0086] It can be seen that the dielectric constant of this heat-conducting part is not significantly different from that of 96 alumina ceramic. The key difference lies in the dielectric loss; the loss of the heat-conducting part is hundreds of times that of ordinary 96 alumina ceramic, meaning that this heat-conducting plate dissipates heat much faster.

[0087] Meanwhile, the heat-conducting part is made of a highly insulating material, which can meet the requirements of leakage current ≤0.2mA within 2s under 1500V voltage and insulation resistance ≥200MΩ under 500V voltage.

[0088] Table 1: Temperature test data of PA66 plastic applied to various locations on the battery top cover.

[0089]

[0090] Table 2: Temperature test data of the thermally conductive silicone coating applied to various locations on the battery top cover.

[0091]

[0092] Table 3: Temperature test data of PPS plastic thermal conductive parts applied at various locations on the battery top cover.

[0093]

[0094] Table 4: Temperature test data of the upper plastic coating of the ceramic thermal conductive part applied at various locations on the battery top cover.

[0095]

[0096] The four tables above show the temperature performance of the battery top cover made of PA66 plastic, silicone, PPS, and ceramic thermal conductive parts during a fixed-time overcurrent test.

[0097] It can be seen that:

[0098] 1. Performance of standard PA66 plastic group

[0099] Riveted block (polar heating core): The temperature of 6 measuring points is concentrated at 93~95.2℃, with an average temperature as high as 93.8℃. The heat source is severely congested and cannot be dissipated.

[0100] Cover plate (outer shell heat dissipation structure): The temperature at the measuring point is only 70.9~78.1℃, with an average of 74.3℃, and the heat dissipation end receives almost no heat.

[0101] Obviously, the top plastic of PA66 plastic material has poor thermal conductivity and high thermal resistance. When a large current flows, the heat generated by the electrode is blocked, and the cooling rate is extremely slow. The temperature difference between the hot and cold ends is as high as 19.5℃, and the problem of local hot spots is extremely prominent.

[0102] 2. The plastic coating with this ceramic thermal conductive part

[0103] The average temperature of the heat source end of the riveting block is 90.1℃, which is 3.7℃ lower than that of the PA66 plastic solution, and the temperature rise of the core heat source is significantly suppressed.

[0104] Heat dissipation end of the cover: The average temperature of the plane is 82.8℃, which is 8.5℃ higher than that of the PA66 plastic solution, indicating that the heat is efficiently conducted to the overall structure of the top cover to participate in heat dissipation.

[0105] Temperature uniformity:

[0106] The overall temperature difference dropped sharply to 7.3℃, which is more than 62% smaller than that of PA66 plastic. The temperature uniformity of the entire cover plate was greatly improved, with no extreme local high temperatures.

[0107] At the same time, by Figure 1 and Figure 2 The thermal imaging clearly shows that the heat from the PA66 plastic solution is concentrated at a very small heat-generating point, resulting in a concentrated and glaring light spot, indicating poor heat dissipation. Conversely, the heat from the upper plastic part using thermally conductive silicone is distributed more evenly, demonstrating better heat dissipation.

[0108] To improve heat dissipation performance, PPS plastic and thermally conductive silicone can be used to replace the aforementioned heat-conducting components. Figure 3 and Figure 4 It can be seen that the heat from the plastic is spread out and distributed evenly, resulting in good heat dissipation.

[0109] Example 2

[0110] This thermally conductive upper plastic part includes a plastic part 1 and a thermally conductive part 2. The plastic part 1 is made of PPS plastic and its working temperature is 260℃. The plastic part 2 is cylindrical with an open top and a through mounting hole 3 at the bottom. The diameter of the mounting hole 3 is 0.3mm larger than that of the thermally conductive part.

[0111] The heat-conducting part 2 comprises, by weight, 85 parts of aluminum oxide (Al2O3), 11 parts of zirconium oxide (ZrO2), and 0.7 parts of yttrium oxide (Y2O3);

[0112] The processing method for the heat-conducting part includes the following steps:

[0113] A. Green body preparation: The alumina, zirconium oxide and yttrium oxide components in the above weight ratio are thoroughly mixed to obtain a uniform material; the material is mixed with water at a weight ratio of 1:0.5, stirred evenly, and then pressed into sheet-shaped green bodies;

[0114] B. One-time sintering: The green billet is placed in a sintering furnace and heated to 500°C at a heating rate of 0.5°C / min, and then heated to 1500°C at a heating rate of 8°C / min. The temperature is held for 10 minutes to achieve rapid densification of the alumina matrix.

[0115] C. Secondary sintering: After the first sintering is completed, the temperature is lowered to 1400℃ at a cooling rate of 8℃ / min and held for 5 hours to eliminate internal stress and promote uniform diffusion of yttrium oxide.

[0116] D. Hot isostatic pressing: The billet after secondary sintering is placed in a hot isostatic pressing equipment, high-purity argon is introduced, pre-pressurized to 40MPa, heated to 1400℃, pressure increased to 160MPa, and held at the temperature for 2 hours to ensure that the billet is completely densified.

[0117] E. Surface treatment: Grind and clean the surface of the heat-conducting part to remove the surface oxide layer and impurities;

[0118] F. Assembly: Install the heat-conducting part into the mounting hole of the plastic part to complete the overall assembly.

[0119] The parameters of the finished thermally conductive part in this embodiment are as follows compared to those of 96% alumina ceramic:

[0120] II. Mechanical Properties:

[0121] II. Electrical Properties

[0122] The dielectric constant of the thermally conductive part is 12.33 and the dielectric loss is 0.091% at 1MHz.

[0123] Conversely, 96% alumina ceramic has a dielectric constant of 9.4 and a dielectric loss of 0.0002% at 1MHz.

[0124] It can be seen that the dielectric constant of this heat-conducting part is not significantly different from that of 96 alumina ceramic. The key difference lies in the dielectric loss; the loss of the heat-conducting part is hundreds of times that of ordinary 96 alumina ceramic, meaning that this heat-conducting plate dissipates heat much faster.

[0125] Meanwhile, the heat-conducting part is made of a highly insulating material, which can meet the requirements of leakage current ≤0.2mA within 2s under 1500V voltage and insulation resistance ≥200MΩ under 500V voltage.

[0126] Example 3

[0127] This thermally conductive upper plastic includes a plastic part 1 and a thermally conductive part 2. The plastic part 1 is made of LCP plastic and its working temperature is 270℃. The plastic part 1 is cylindrical with an open top and a through mounting hole 3 at the bottom. The diameter of the mounting hole 3 is 0.6mm larger than that of the thermally conductive part 2.

[0128] The thermally conductive component comprises, by weight, 91 parts of alumina (Al2O3), 8.5 parts of zirconium oxide (ZrO2), and 0.4 parts of yttrium oxide (Y2O3);

[0129] The processing method for the heat-conducting part includes the following steps:

[0130] A. Green body preparation: The alumina, zirconium oxide and yttrium oxide components in the above weight ratio are thoroughly mixed to obtain a uniform material; the material is mixed with water at a weight ratio of 1:0.5, stirred evenly, and then pressed into sheet-shaped green bodies;

[0131] B. First sintering: The green billet is placed in a sintering furnace and heated to 600°C at a heating rate of 1°C / min, and then heated to 1560°C at a heating rate of 12°C / min. It is held for 3 minutes to rapidly densify while avoiding coarsening of ZrO2 grains.

[0132] C. Secondary sintering: After the first sintering is completed, the temperature is lowered to 1450℃ at a rate of 10℃ / min and held for 2 hours to eliminate internal stress.

[0133] D. Hot isostatic pressing: The billet after secondary sintering is placed in a hot isostatic pressing equipment, high-purity argon is introduced, pre-pressurized to 60MPa, heated to 1480℃, pressure increased to 180MPa, and held at that temperature for 1 hour.

[0134] E. Surface treatment: Polish the surface of the heat-conducting part to improve surface smoothness;

[0135] F. Assembly: Install the heat-conducting part into the mounting hole of the plastic part to complete the overall assembly.

[0136] The parameters of the finished thermally conductive part in this embodiment are as follows compared to those of 96% alumina ceramic:

[0137] III. Mechanical Properties:

[0138] II. Electrical Properties

[0139] The dielectric constant of the thermally conductive part is 12.33 and the dielectric loss is 0.086% at 1MHz.

[0140] Conversely, 96% alumina ceramic has a dielectric constant of 9.4 and a dielectric loss of 0.0002% at 1MHz.

[0141] It can be seen that the dielectric constant of this heat-conducting part is not significantly different from that of 96 alumina ceramic. The key difference lies in the dielectric loss; the loss of the heat-conducting part is hundreds of times that of ordinary 96 alumina ceramic, meaning that this heat-conducting plate dissipates heat much faster.

[0142] Meanwhile, the heat-conducting part is made of a highly insulating material, which can meet the requirements of leakage current ≤0.2mA within 2s under 1500V voltage and insulation resistance ≥200MΩ under 500V voltage.

[0143] This heat-conducting part has higher mechanical strength and stable heat dissipation performance.

[0144] However, it also has obvious drawbacks, namely: the dielectric constant increases and the dielectric loss increases significantly, which ultimately leads to a significant decrease in the electrical performance of the heat-conducting part.

[0145] Conversely, since the heat-conducting part is used for heat dissipation of the battery cover, the degradation of electrical performance will not have a negative impact on its application.

[0146] The technical solutions of the present invention described above provide solutions that are significantly different from those of the prior art, addressing the problem that existing technical solutions are too simplistic. The parts not covered in this application are the same as or can be implemented using existing technologies, and will not be described in detail here.

[0147] The technical solutions in the above embodiments have clearly and completely described the content of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. A thermally conductive upper plastic, comprising a plastic part and a thermally conductive part, characterized in that, The aforementioned plastic part is cylindrical with an open top, and the lower end of the plastic part has a through mounting hole. The aforementioned heat-conducting part matches the mounting hole and is connected to the mounting hole. The heat-conducting part can prevent heat from accumulating on the upper plastic part.

2. The thermally conductive plastic coating according to claim 1, characterized in that, The heat-conducting component comprises, by weight ratio: Alumina (AL2O3) 85-91 parts Zirconium oxide (ZrO2) 8.5-11 parts Yttrium trioxide (Y2O3) 0.4–0.7 parts.

3. The thermally conductive top plastic according to claim 2, characterized in that, The heat-conducting component comprises, by weight ratio, the following: Alumina (AL2O3) 89.7 parts Zirconium oxide (ZrO2) 9.38 parts 0.52 parts of yttrium trioxide (Y2O3).

4. The thermally conductive top plastic according to claim 1, characterized in that, The thermally conductive part is either PPS plastic or thermally conductive silicone.

5. The thermally conductive plastic coating according to claim 1, characterized in that, The plastic part is made of either PPS or LCP plastic, and the operating temperature of the plastic part is -80℃ to 600℃.

6. The thermally conductive plastic coating according to claim 1, characterized in that, The diameter of the mounting hole is larger than that of the heat-conducting part, so that when the plastic part is deformed by force, the inner edge of the mounting hole can abut against the outer edge of the heat-conducting part.

7. A method for processing a heat-conducting part, characterized in that, The processing method of the heat-conducting part, comprising the upper plastic as described in any one of claims 1-3, includes the following steps: A. Green body preparation: The heat-conducting components in a set ratio are thoroughly mixed to obtain the material. The material is then mixed with water at a weight ratio of 1:0.5 and a sheet-like green body is prepared. B. Single sintering: High-temperature short-time sintering at 1500-1560℃ (3-10 min); C. Secondary sintering: The billet after primary sintering is sintered at 1400-1450℃ for 2-5 hours. D. Hot isostatic pressing: The billet after secondary sintering is subjected to a mild process of 1400-1480℃, 160-180 MPa, and 1-2 h to ensure complete densification while maintaining the content of ZrO2 tetragonal phase.

8. The processing method for the heat-conducting part according to claim 7, characterized in that, After step B is completed, the process is converted to secondary sintering at a cooling rate of 8-10℃ / min to reduce thermal shock and phase transformation cracks.

9. The processing method for the heat-conducting part according to claim 7, characterized in that, Step D involves processing in an inert gas environment.

10. The processing method of the heat-conducting part according to claim 7, characterized in that, After step D, the heat-conducting part undergoes surface treatment.

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