Cooling structure for DC capacitor and inverter

Abstract

The utility model relates to a cooling structure for a DC capacitor, and the structure comprises a housing which is configured to define a first cavity and a second cavity, the first cavity is used for accommodating the DC capacitor, and the second cavity is used for allowing a refrigerant to flow through; and at least one heat pipe, a first end portion of the heat pipe is combined with a first shell wall portion of the shell defining the first cavity and forms a heat flow path therebetween, and a second end portion of the heat pipe is combined with a second shell wall portion of the shell defining the second cavity and forms a heat flow path therebetween. The utility model also relates to an inverter with the cooling structure.

Description

TECHNICAL FIELD

[0001] The utility model relates to cooling technical field, especially a cooling structure for DC (Direct Current, direct current) capacitor and inverter with the cooling structure. BACKGROUND

[0002] Recently, various efforts have been made for the miniaturization and light weight of inverters for electric vehicles or automobiles. A particularly prominent problem is that while miniaturization and light weight are pursued, heat dissipation of various internal components also needs to be achieved to ensure the durability of the inverter. In terms of DC capacitors, which directly affect the durability of the inverter, the temperature of the DC capacitors is currently managed using air-cooled or water-cooled cooling methods.

[0003] Generally, in an inverter using an indirect cooling method for DC capacitors, a DC capacitor is mounted in an inverter housing, and a dedicated cooling device using a natural air cooling method or a cooling water circulation method is provided on the opposite side of the housing where the DC capacitor is installed. In this cooling device, heat is transferred from the DC capacitor to the coolant (i.e., cooling air or cooling water) through the housing. This cooling method greatly limits the arrangement position and size design of the DC capacitor. In addition, the dedicated cooling water flow path design used in the cooling device increases the design difficulty, and in addition, an additional flow path sealing design is required, such as using friction stir welding technology to connect a sealing plate to close the opening of the cooling water chamber. The manufacturing process of the entire inverter device is complicated, and the reliability of the device is low. SUMMARY

[0004] The utility model aims at solving at least one of the above problems and / or other problems in the prior art.

[0005] To achieve the above-mentioned purpose, according to one aspect of the utility model, a cooling structure for DC capacitor is provided, characterized in that it comprises:

[0006] an outer shell made of a heat-conducting material, which is configured to define a first cavity for accommodating a DC capacitor and a second cavity for allowing a coolant to flow through; and

[0007] at least one heat pipe, a first end of the heat pipe being combined with a first shell wall part of the outer shell defining the first cavity and forming a heat flow path therebetween, and a second end of the heat pipe being combined with a second shell wall part of the outer shell defining the second cavity and forming a heat flow path therebetween.

[0008] The heat from the DC capacitor is continuously transferred to the refrigerant, and the arrangement of the heat pipe eliminates the need to limit the second cavity to the upper and lower parts of the first cavity, greatly increasing the flexibility of the inverter design, simplifying the sealing design of the shell and the first and second cavities, and increasing the reliability of the entire inverter device.

[0009] According to an embodiment of the present application, the first end and / or the second end of the heat pipe is embedded in a corresponding groove formed on the outer surface of the corresponding shell wall part. By this configuration, the positioning and installation of the heat pipe are facilitated, and the maintenance or replacement of parts is also facilitated.

[0010] According to an embodiment of the present application, a thermally conductive filling material is provided between the first end and / or the second end of the heat pipe and the inner wall of the corresponding groove. In this way, the heat dissipation of the DC capacitor is ensured with maximum heat transfer efficiency.

[0011] According to an embodiment of the present application, a circumferential rib extending circumferentially along the groove is formed on the inner two side walls of the groove, for fixing the heat pipe by press fitting and forming thermal contact with the heat pipe. Therefore, the fixing strength of the heat pipe and the sufficient heat contact area with the shell wall part are ensured.

[0012] According to an embodiment of the present application, the circumferential ribs are arranged at intervals along the longitudinal extension direction of the groove. In this way, it is ensured that each part in the extension direction of the heat pipe is fixed and installed, preventing the occurrence of peristalsis or displacement.

[0013] According to an embodiment of the present application, a longitudinal rib extending longitudinally along the groove is formed on the inner bottom wall of the groove, and the longitudinal rib is configured to engage with and form thermal contact with the bottom surface of the heat pipe embedded in the groove. By this means, the outer peripheral surface of the heat pipe does not need to be strictly consistent with the inner wall arc of the groove on the shell wall part, and the groove bottom wall and the heat pipe still have a sufficient density of heat transfer flow paths.

[0014] According to an embodiment of the present application, the first shell wall part and the second shell wall part are a shell wall formed integrally on the same side of the housing via the intermediate shell wall part, and the intermediate part of the heat pipe between the first end and the second end is embedded in the groove formed in the intermediate shell wall part. From the appearance, the heat pipe is embedded in the housing, ensuring that the heat pipe is always kept in a fixed position, so that heat transfer is carried out with the expected thermal conductivity and thermal performance, and in addition, the heat pipe is prevented from peristalsis or disembedding from the groove in the case of vibration or impact of the entire device.

[0015] According to one embodiment of the present invention, the first shell wall portion and the second shell wall portion are located at different height planes. Therefore, the characteristic that the heat pipe can be extended as needed in the longitudinal length is advantageously utilized, so that the size and positioning of the first cavity and the second cavity in terms of height are not limited in any way.

[0016] According to another aspect of the present invention, an inverter is provided, including a DC capacitor, wherein the inverter includes the cooling structure for the DC capacitor described above.

[0017] According to one embodiment of this invention, the DC capacitor is a DC-Link capacitor. A DC-Link capacitor (DC-support capacitor) is used to connect the intermediate voltage link between the DC power supply and the inverter. It plays an important role in the power conversion system, providing energy storage and smoothing DC voltage.

[0018] The cooling structure of this invention enables the miniaturization and weight reduction of the inverter while simultaneously dissipating heat from the DC capacitor, preventing it from overheating and being damaged. In particular, the use of heat pipes allows for greater flexibility in the arrangement and design of the DC capacitor, thus broadening the application range of inverter products with this cooling structure. Attached Figure Description

[0019] The features and advantages of this utility model will become clear from the following detailed description provided with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and therefore should not be considered as limitations on this utility model, wherein:

[0020] Figure 1 A schematic diagram of an inverter according to an exemplary embodiment of the present invention is shown, wherein a cooling structure for a DC capacitor is shown.

[0021] Figure 2 Show along Figure 1 The diagram shows a cross-sectional view of the inverter obtained by the AA line.

[0022] Figure 3 Show Figure 2 The arrangement of heat pipes in the cooling structure shown.

[0023] Figure 4 schematically shown Figure 2 The structure of the groove in the cooling structure shown.

[0024] Figure 5 The heat pipes are arranged in a press-fit manner. Figure 4 In the groove shown.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Inverter; 10. DC capacitor; 20. Cooling structure; 201. Housing; 202. Heat pipe; 202a. First end; 202b. Second end; 201a. First shell wall portion; 201b. Second shell wall portion; 201c. Intermediate shell wall portion; V1. First cavity; V2. Second cavity; Pa. Flow path; R. Groove; M. Thermally conductive filling material; CRb. Circumferential rib; LRb. Longitudinal rib. Detailed Implementation

[0027] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to more fully understand and implement the present invention. However, it will be apparent to those skilled in the art that implementations of the present invention may not include some of these specific details. Furthermore, it should be understood that the present invention is not limited to the specific embodiments described. Rather, the present invention can be conceived to be implemented with any combination of the features and elements described below, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are for illustrative purposes only and should not be construed as elements or limitations of the claims unless expressly set forth in the claims.

[0028] The terms "first" and "second" are used below to describe the elements of this application. These terms are used only to distinguish the individual elements and not to limit the nature, order, or number of these elements. The terms "comprising" and "having" are used to indicate an open-ended inclusion and mean that there may be additional elements / components besides those listed.

[0029] Combination Figure 1 and Figure 2 As shown, the inverter 1 according to the present invention includes a DC capacitor 10 and a cooling structure 20 for the DC capacitor. The cooling structure includes a housing 201 made of a thermally conductive material (e.g., metal) and at least one heat pipe 202. The housing 201 is configured to define a first cavity V1 and a second cavity V2. The DC capacitor 10 is arranged in the first cavity V1. A flow path Pa for refrigerant (e.g., cooling water) is arranged in the second cavity V2. The first cavity and the second cavity are sealed to each other. A first end 202a of the heat pipe 202 is coupled to a first shell wall portion 201a of the housing defining the first cavity and forms a heat flow path therebetween. A second end 202b of the heat pipe 202 opposite to the first end is coupled to a second shell wall portion 201b of the housing defining the second cavity and forms a heat flow path therebetween. Figure 1In the illustrated embodiment, the first shell wall portion 201a is located at the top of the first cavity V1, and the second shell wall portion 201b is located at the top of the second cavity V2. The first shell wall portion 201a and the second shell wall portion 201b are formed as an integral shell wall via the intermediate shell wall portion 201c. In the illustrated embodiment, the first shell wall portion 201a and the second shell wall portion 201b are located at different height planes.

[0030] Referring to Figure 2 As shown, the first end portion 202a of the heat pipe 202 is embedded in a recess R formed on the outer surface of the first shell wall portion 201a. The second end portion 202b of the heat pipe 202 is embedded in a recess R formed on the outer surface of the second shell wall portion 201b. The intermediate portion of the heat pipe between the first end portion and the second end portion is embedded in a recess formed on the intermediate shell wall portion 201c. As shown, the heat pipe 202 is arranged in a generally vertically standing Z-shaped manner. According to the present application, the routing of the heat pipe is flexibly arranged according to the specific positional relationship between the first cavity and the second cavity, and the flexibly arranged heat pipe is conducive to conducting heat from the DC capacitor in the first cavity to the refrigerant in the second cavity, thereby reducing the temperature of the DC capacitor.

[0031] Referring to Figure 3 As shown, in an advantageous embodiment, a thermally conductive filling material M (such as thermally conductive glue or solder) is provided between the first end portion of the heat pipe 202 and the inner wall of the recess R on the first shell wall portion, and / or a thermally conductive filling material M (such as thermally conductive glue or solder) is provided between the second end portion of the heat pipe 202 and the inner wall of the recess on the second shell wall portion. By applying thermally conductive glue or solder, the gap between the heat pipe and the inner wall of the recess is filled, which is more conducive to heat conduction and achieves efficient heat transfer at both ends of the heat pipe. In addition, the application of solder also facilitates the anchoring of the heat pipe in the recess, enhancing the bonding strength of the heat pipe and the shell wall portion. Of course, solder can also be provided between the intermediate portion of the heat pipe between the first end portion and the second end portion and the inner wall of the recess on the corresponding intermediate shell wall portion to strengthen the fixation of the heat pipe.

[0032] Optionally or additionally, circumferential ribs CRb extending circumferentially along the recess are formed on the two inner side walls of the recess R, as shown in Figure 4 The circumferential ribs extend along the curvature of the inner wall of the recess. Advantageously, the circumferential ribs CRb are arranged at intervals along the longitudinal extension direction of the recess. The circumferential ribs CRb achieve a press fit between the heat pipe 202 and the inner wall of the recess, thereby fixing the heat pipe in the recess, and the engagement surface between the heat pipe and the circumferential ribs is tightly fitted, which facilitates the formation of a low-thermal-resistance heat flow path between the two. Of course, the gap between the circumferential ribs can also be filled with thermally conductive glue or solder to make full use of all possible heat flow paths between the heat pipe and the inner wall of the recess for heat transfer. In Figure 4In the illustrated embodiment, the inner bottom wall of the recess R is formed with a longitudinal rib LRb extending along the longitudinal direction of the recess, which is configured to engage with and form thermal contact with the bottom surface of the heat pipe embedded in the recess. With the press fit of the longitudinal rib with the bottom surface of the heat pipe, it is also beneficial to avoid the existence of a large gap between the bottom surface of the heat pipe and the bottom of the inner wall of the recess, thus further improving the heat transfer efficiency. In this way, a supporting force is applied to both sides and the bottom of the heat pipe, ensuring that the heat pipe is fixed from at least three connection points (supporting points) to prevent the heat pipe from moving or shifting.

[0033] Referring to Figure 5 As shown, the first end or the second end of the heat pipe 202 is embedded in the corresponding recess R. Due to the extrusion force exerted by the circumferential rib CRb on both sides of the heat pipe, the heat pipe is advantageously anchored in the recess.

[0034] In the inverter according to the present application, the cooling structure 20 is directly integrated on the shell of the inverter 1, or in other words, the shell of the cooling structure 20 is formed in one piece with the shell of the inverter. In addition, the recess on the shell for embedding the heat pipe can be formed simultaneously during the manufacturing process of the shell, without the need to involve excessive process steps and the manufacturing of other components.

[0035] Although in the illustrated embodiment, the first shell wall portion and the second shell wall portion are located on the same side of the shell, it can be understood that the first shell wall portion and the second shell wall portion can be located on different sides of the shell, for example, the first shell wall portion is located on the top of the shell, and the second shell wall portion is located on the circumferential side or the bottom of the shell. The size and area of the first shell wall portion and the second shell wall portion are selected and positioned according to the specific configuration of the DC capacitor cavity and the refrigerant flow cavity.

[0036] In this context, the combination of the end of the heat pipe and the shell wall portion means that there is a physical engagement between the two, an engagement surface is formed, and heat can be transferred between the two through this engagement surface. Therefore, although the end of the heat pipe is shown in the figure to have almost half of its circumferential surface exposed to the air, it can be understood that the cooling structure according to the present application also includes the case where the corresponding end of the heat pipe is embedded in the shell wall portion, i.e. the end of the heat pipe is inserted into the embedded hole formed in the shell wall portion and the circumferential surface of the heat pipe is completely surrounded by the heat-conducting material of the shell.

[0037] Therefore, according to the cooling structure according to the present application, by flexibly routing the heat pipe in the shell originally possessed by the inverter, a directional heat transfer path is formed between the DC capacitor containing cavity and the refrigerant flow cavity, which advantageously guides heat from the DC capacitor to the refrigerant in the refrigerant flow cavity, so that the arrangement relationship between the DC capacitor containing cavity and the refrigerant flow cavity is no longer limited to the position relationship of being stacked one above the other, greatly improving the flexibility of inverter design, which is beneficial to improve the durability of the inverter and realize the miniaturization and light weight of the inverter.

[0038] Industrial applicability

[0039] The cooling structure according to the present application can be applied to power electronic components with inverters, such as frequency converters, DC-DC converters, battery thermal management systems, etc.

[0040] The working principle of the cooling structure according to the present application will be explained below in connection with Figure 1 and Figure 2

[0041] The first end portion of the heat pipe is in thermal contact with the first shell wall portion. Thus, the heat (heat generated by the DC capacitor) accumulated in the first cavity is conducted to the first end portion of the heat pipe via the heat-conductive pad or the first shell wall portion. The working medium inside the heat pipe in the region of the first end portion of the heat pipe absorbs this part of the heat and changes from liquid to gaseous state and flows from the first end portion of the heat pipe to the second end portion of the heat pipe. Since the second end portion of the heat pipe is in thermal contact with the second shell wall portion of the coolant flow cavity and the coolant has a lower temperature, the gaseous working medium flowing to the second end portion of the heat pipe liquefies upon cooling and releases heat, and this part of the released heat is transferred to the coolant in the second cavity (coolant flow cavity) via the wall of the heat pipe and the second shell wall portion, and the coolant carries away this part of the heat, thereby reducing the temperature of the DC capacitor. The liquefied working medium flows back to the first end portion of the heat pipe under the action of capillary force, then absorbs heat in the region of the first end portion of the heat pipe, vaporizes and gasifies, flows to the second end portion of the heat pipe and liquefies. In this way, the heat is continuously transferred from the DC capacitor to the coolant and carried away by the coolant. The coolant can be cooling water or cooling air.

[0042] Generally, the thermal conductivity of a heat pipe is 10-1000 times that of solid copper. With the help of a heat pipe, the heat transfer efficiency can be effectively improved. In addition, the wiring of the heat pipe is simple and easy to implement, which is conducive to flexible arrangement of the DC capacitor cavity and the coolant flow cavity or other heat dissipation devices, improves the design flexibility and has higher reliability.

[0043] Various modifications and variations to the disclosed embodiments of the present application can be made without departing from the scope or spirit of the present application. Other embodiments of the present application will be apparent from consideration of the specification and practice of the present application disclosed herein. For example, it will be apparent to one of skill in the art that the application can be practiced without the specific details set forth above. Further, it will be apparent that various implementations utilizing the principles of the present application can be achieved with less than all the features shown and described above. It will also be apparent that features described for one or more implementations can be combined with features described for one or more other implementations. Other implementations can be apparent to those of ordinary skill in the art given the benefit of this disclosure. Accordingly, the specification and examples should be considered exemplary only, with the true scope and spirit of the application indicated by the following claims.​

Claims

1. A cooling structure for a DC capacitor, characterized by, Comprising: an outer shell made of a thermally conductive material, configured to define a first cavity for accommodating a DC capacitor and a second cavity for passing a coolant therethrough; and at least one heat pipe, a first end portion of the heat pipe being combined with and forming a heat flow path between a first shell wall portion of the outer shell defining the first cavity, and a second end portion of the heat pipe being combined with and forming a heat flow path between a second shell wall portion of the outer shell defining the second cavity. The first end portion and / or the second end portion of the heat pipe is embedded in a corresponding groove formed on an outer surface of the corresponding shell wall portion.

2. The cooling structure according to claim 1, characterized by A thermally conductive filling material is provided between the first end portion and / or the second end portion of the heat pipe and an inner wall of the corresponding groove.

3. The cooling structure according to claim 2, characterized by Circumferential ribs extending circumferentially along the groove are formed on both inner side walls of the groove, for fixing the heat pipe by press fitting and forming thermal contact with the heat pipe.

4. The cooling structure according to claim 3, characterized by The circumferential ribs are arranged at intervals along a longitudinal extension direction of the groove.

5. The cooling structure according to claim 4, characterized by A longitudinal rib extending longitudinally along the groove is formed on an inner bottom wall of the groove, configured to engage and form thermal contact with a bottom surface of the heat pipe embedded in the groove.

6. The cooling structure according to claim 5, characterized by The first shell wall portion and the second shell wall portion are located on the same side of the outer shell and are formed as an integral shell wall via an intermediate shell wall portion, and an intermediate portion of the heat pipe between the first end portion and the second end portion is embedded in a groove formed in the intermediate shell wall portion.

7. The cooling structure according to any one of claims 1 to 6, characterized by The first shell wall portion and the second shell wall portion are located in different height planes.

8. The cooling structure according to claim 7, characterized by The inverter comprises a cooling structure according to any one of claims 1-8.

9. An inverter comprising a DC capacitor, characterized by The DC capacitor is a DC-Link capacitor.

10. The inverter of claim 9, wherein, ​

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