Thin film capacitor and current conversion unit having same

Abstract

The utility model relates to a film capacitor and a current conversion unit with the same. The thin film capacitor comprises a capacitor shell, the capacitor shell is provided with an end wall and a peripheral wall arranged in the circumferential direction of the end wall, the end wall and the peripheral wall jointly define a containing space of the capacitor shell, and the end wall is constructed to be a heat conduction metal wall; the busbar is arranged in the accommodating space of the capacitor shell and is provided with a connecting end which is opposite to the end wall and extends out of the accommodating space; the capacitor cores are arranged in the accommodating space of the capacitor shell and are respectively connected to the busbar; and the sealing glue is filled in the accommodating space of the capacitor shell and separates the plurality of capacitor cores from the heat-conducting metal wall.

Description

Technical Field

[0001] The utility model relates to power supply equipment, in particular to a film capacitor and a current conversion unit having the same. Background Art

[0002] In recent years, environmental protection related markets such as electric vehicles, hybrid electric vehicles, solar and wind power generation systems have expanded rapidly around the world. In such devices, capacitors and power modules are the core system components in motor drive controllers, which directly affect the size and life of the controller. Among various capacitors, film capacitors are more suitable for high-power devices because of their non-polarity, high voltage resistance and high stability.

[0003] Traditional film capacitors, such as DC capacitors, can be electrically connected to power semiconductor devices such as IGBT modules and share a heat sink. During operation, the capacitor core generates heat, which is dissipated outward through the capacitor's internal potting material, the capacitor housing, and the heat sink. Generally speaking, the heat dissipation effect is not ideal.

[0004] According to the industry's capacitor specification standards, the maximum operating temperature of capacitors is generally 105°C, and when the operating temperature exceeds 85°C, it needs to be derated. It can be said that the operating temperature seriously affects the life and application of capacitors.

[0005] Therefore, there is a certain demand in the industry for improving capacitors to enhance their heat dissipation capabilities. Utility Model Content

[0006] The utility model aims to provide a film capacitor, which can at least solve some of the above technical problems.

[0007] The utility model also aims to provide a current conversion unit using the improved film capacitor.

[0008] According to one aspect of the utility model, a film capacitor is provided, comprising: a capacitor housing, having an end wall and a peripheral wall arranged along the circumference of the end wall, and the end wall and the peripheral wall jointly enclose a storage space of the capacitor housing, wherein the end wall is configured as a heat-conducting metal wall; a busbar, arranged in the storage space of the capacitor housing and having a connecting end extending from the storage space with its back facing the end wall; a plurality of capacitor cores connected in parallel, arranged in the storage space of the capacitor housing and respectively connected to the busbar; and a sealing glue filled in the storage space of the capacitor housing and separating the plurality of capacitor cores from the heat-conducting metal wall.

[0009] According to the film capacitor provided by the present solution, the end wall of the capacitor housing is constructed as a heat-conducting metal wall, so that the heat generated by the capacitor core during operation can be discharged through the sealing glue and the heat-conducting metal wall, preventing heat from accumulating inside the film capacitor, improving the heat dissipation efficiency, and extending the service life of the film capacitor. In addition, the sealing glue completely separates the capacitor core from the heat-conducting metal wall, preventing the capacitor core from directly contacting the metal wall and causing a short circuit.

[0010] In some embodiments, the peripheral wall of the capacitor housing is configured as a heat-conductive metal wall, and the sealing glue separates the plurality of capacitor cores from the end wall and the peripheral wall of the capacitor housing.

[0011] According to the film capacitor provided by this solution, the end wall and the peripheral wall of the capacitor shell are constructed as heat-conducting metal walls, and the heat generated by the capacitor core can be dissipated through the end wall and the peripheral wall, further improving the heat dissipation efficiency and improving the working environment of the capacitor core.

[0012] In some embodiments, the heat-conducting metal wall is an aluminum wall. The heat-conducting metal wall constructed in this way has good thermal conductivity and low cost.

[0013] In some embodiments, the film capacitor further comprises a plurality of heat sinks disposed on an end wall of the capacitor housing, wherein the plurality of heat sinks are arranged at intervals on the entire surface of the end wall.

[0014] In some embodiments, at least a portion of the plurality of heat sinks are integrally formed with the capacitor housing, or at least a portion of the plurality of heat sinks are detachably connected to the capacitor housing.

[0015] In some embodiments, the busbar includes a first pole and a second pole insulated from each other and each having a connection end, wherein the plurality of capacitor cores are each connected to the first pole at their first end, and the plurality of capacitor cores are each connected to the second pole at their second end.

[0016] In some embodiments, the first pole and the second pole are arranged opposite to each other and spaced apart, and the plurality of capacitor cores are arranged between the first pole and the second pole.

[0017] In some embodiments, the busbar includes a first pole and a second pole insulated from each other, and also includes a common pole, wherein the first pole, the second pole and the common pole are each formed with a connecting end, wherein a first group of capacitor cores among the multiple capacitor cores are each connected to the first pole with their first ends, and a second group of capacitor cores among the multiple capacitor cores are each connected to the second pole with their first ends, and the first group of capacitor cores and the second group of capacitor cores are each connected to the common pole with their second ends.

[0018] In some embodiments, the first pole and the second pole are arranged side by side, the common pole and the first pole and the second pole are opposite to each other and spaced apart, wherein a first group of capacitor cores is arranged between the first pole and the common pole, and the second group of capacitor cores is arranged between the second pole and the common pole.

[0019] According to another aspect of the utility model, a current conversion unit is provided, comprising: a unit housing; an electrical network accommodated in the unit housing and configured to convert the received current; wherein the electrical network comprises the aforementioned thin film capacitor.

[0020] Some of the other features and advantages of the present invention will be apparent to those skilled in the art after reading this application, and the other parts will be described in the following specific embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, wherein:

[0022] Figure 1 is a three-dimensional cross-sectional view of a current conversion unit according to an embodiment of the utility model;

[0023] Figure 2 is a planar cross-sectional view of a current conversion unit according to an embodiment of the utility model;

[0024] Figure 3 is a schematic diagram of a film capacitor according to a first embodiment of the utility model at an angle;

[0025] Figure 4 yes Figure 3 A schematic diagram of the film capacitor from another angle is shown;

[0026] Figure 5 is an exploded schematic diagram of a film capacitor according to a first embodiment of the utility model;

[0027] Figure 6 It is a schematic diagram of an exploded view of a film capacitor according to a second embodiment of the utility model.

[0028] Description of reference numerals:

[0029] 1-current conversion unit; 2-unit housing; 3-film capacitor; 4-capacitor housing; 41-

[0030] End wall; 42-peripheral wall; 43-accommodation space; 5-busbar; 51-first pole; 511-first connection

[0031] Terminal; 52-second pole; 521-second connection terminal; 53-common pole; 531-third connection terminal;

[0032] 54-insulating layer; 6-capacitor core; 61-first group of capacitor cores; 62-second group of capacitor cores

[0033] Sub; 7-sealing glue; 8-heat sink DETAILED DESCRIPTION

[0034] Now, with reference to the accompanying drawings, schematic schemes of the thin film capacitor and the current conversion unit having the same disclosed by the utility model are described in detail. Although the drawings are provided to present some embodiments of the utility model, the drawings do not have to be drawn according to the dimensions of the specific embodiments, and certain features may be enlarged, removed or partially cut to better illustrate and explain the disclosure of the utility model. Some components in the drawings can be adjusted in position according to actual needs without affecting the technical effect. The phrase "in the drawings" or similar terms appearing in the specification do not necessarily refer to all drawings or examples.

[0035] Certain directional terms used to describe the drawings below, such as "inside", "outside", "above", "below" and other directional terms, will be understood to have their normal meanings and refer to those directions involved when the drawings are normally viewed. Unless otherwise specified, the directional terms described in this specification are basically in accordance with the conventional directions understood by those skilled in the art.

[0036] The terms "first", "first", "second", "second" and the like used in the present invention do not indicate any order, quantity or importance, but are used to distinguish one component from other components.

[0037] The utility model aims to provide a film capacitor, which is suitable for current conversion units such as rectifiers, inverters, DC-DC converters, etc. The film capacitor has a shell containing a capacitor core configured such that the end wall (or "bottom wall") is a heat-conducting metal wall, or the end wall and the peripheral wall arranged around the end wall are both heat-conducting metal walls, so that the heat generated by the capacitor core during operation can be quickly dissipated through the heat-conducting metal wall, avoiding heat accumulation in the film capacitor, improving the working environment of the capacitor core, and increasing the working stability and service life of the film capacitor.

[0038] Figure 1 and Figure 2 The current conversion unit 1 using the thin film capacitor 3 is shown, wherein the current conversion unit 1 is a three-dimensional cross-sectional view ( Figure 1 ) and plan section view ( Figure 2) is shown, and part of the layout inside the unit housing 2 of the current conversion unit 1 is exposed. The unit housing 2 of the current conversion unit 1 contains an electrical network that performs the current conversion function (AC-DC, or DC-AC, or DC-DC), and the electrical network is composed of many electrical components, and the film capacitor 3 is one of the electrical components, which is usually connected with, for example, an IGBT module, a PCB, etc. In one embodiment, the current conversion unit 1 can be a rectifier, an inverter, or a DC-DC converter in a UPS or UPM.

[0039] Figures 3 to 5 The film capacitor 3 according to the first embodiment of the utility model is shown. As shown in the figure, the film capacitor 3 includes a capacitor housing 4 and an element accommodated in the capacitor housing 4, such as a capacitor core 6. The capacitor housing 4 has an end wall 41 and a peripheral wall 42 arranged circumferentially around the end wall 41. The figure shows that the capacitor housing 4 is constructed in a square shape, and its end wall 41 has four side edges connected in sequence, and the four connected wall segments are sequentially connected to the four side edges to form a peripheral wall 42. The end wall 41 and the peripheral wall 42 are jointly enclosed to form a receiving space 43 of the capacitor housing 4. Of course, the configuration of the capacitor housing 4 can have other deformations to adapt to different installation environments. In one embodiment, the end wall 41 of the capacitor housing 4 is made of a heat-conducting metal material, thereby forming a heat-conducting metal wall. Such an end wall 41 allows the heat generated by the capacitor core 6 during operation to be quickly discharged, thereby improving the heat dissipation efficiency. The peripheral wall 42 can be made of plastic. In another embodiment, the end wall 41 and the peripheral wall 42 are both heat-conducting metal walls made of a heat-conducting metal material, which can further improve the heat dissipation efficiency of the capacitor core 6. Any suitable heat-conducting metal material, such as aluminum or copper, can be selected to prepare the heat-conducting metal wall.

[0040] The capacitor core 6 and the busbar 5 are both fixedly arranged in the accommodating space 43 of the capacitor housing 4. Figure 5As shown, a plurality of capacitor cores 6 are arranged in an array and connected in parallel in the electrical network of the current conversion unit 1. The busbar 5 is used to connect each capacitor core 6 to other devices, such as a PCB. In the embodiment shown, the busbar 5 includes a first pole 51 and a second pole 52, each of which is plate-shaped and has a plurality of junctions. The first pole 51 and the second pole 52 are opposite to each other and spaced apart, wherein the first pole 51 is closer to the end wall 41 of the capacitor housing 4 than the second pole 52. The capacitor core 6 is arranged between the first pole 51 and the second pole 52, and each capacitor core 6 is connected to the first pole 51 at one end and to the second pole 52 at the other end. An insulating layer 54 is provided between the first pole 51 and the second pole 52 to isolate the first pole 51 from the second pole 52 to prevent the first pole 51 from forming a short circuit with the second pole 52. One of the first pole 51 and the second pole 52 can be a positive pole, and the other can be a negative pole. The first pole 51 has a first connection end 511 extending away from the end wall 41 and out of the capacitor housing 4, and the second pole 52 has a second connection end 521 extending away from the end wall 41 and out of the capacitor housing 4. Through the first connection end 511 and the second connection end 521 of the busbar 5, the film capacitor 3 can be connected to other devices.

[0041] After the capacitor core 6 and the busbar 5 are arranged in the accommodation space 43 of the capacitor housing 4, a sealing and insulating sealant 7, such as epoxy resin, is filled into the accommodation space 43. The sealant 7 encapsulates all the capacitor cores 6, separates these capacitor cores 6 from the heat-conducting metal wall of the capacitor housing 4, and prevents them from directly contacting and forming a short circuit. In the illustrated embodiment, the sealant 7 encapsulates both the capacitor core 6 and the busbar 5 in the accommodation space 43 of the capacitor housing 4, and only the first connection end 511 and the second connection end 521 of the busbar 5 are exposed. The capacitor housing 4 can be open on the side opposite to the end wall 41, and after the capacitor core 6 and the busbar 5 and other components are loaded through the open side, a flat surface is constructed on the open side by the injected sealant 7. The heat generated by the capacitor core 6 during operation is dissipated layer by layer through the sealant 7 and the heat-conducting metal wall, and the heat dissipation efficiency is significantly improved compared with the traditional housing.

[0042] In addition, a plurality of heat sinks 8 may be arranged on the end wall 41 of the capacitor housing 4, each heat sink 8 being substantially perpendicular to the end wall 41, and all heat sinks 8 may be evenly spaced and arranged on the entire surface of the end wall 41. After passing through the heat-conducting metal wall, the heat of the capacitor core 6 is further conducted by the heat sink 8 and quickly leaves the film capacitor 3. The heat sink 8 may be integrally formed with the capacitor housing 4, or may be detachably mounted on the end wall 41 of the capacitor housing 4.

[0043] Figure 6A film capacitor 3 according to a second embodiment of the utility model is shown. Similar to the first embodiment, the film capacitor 3 may also include a capacitor housing 4 and an element accommodated in the capacitor housing 4, such as a capacitor core 6. The capacitor housing 4 has an end wall 41 and a peripheral wall 42 arranged circumferentially around the end wall 41. The figure shows that the capacitor housing 4 is constructed in a square shape, and its end wall 41 has four side edges connected in sequence, and the four connected wall segments are sequentially connected to the four end edges to form a peripheral wall 42, so that the end wall 41 and the peripheral wall 42 jointly enclose a storage space 43 of the capacitor housing 4. Of course, the configuration of the capacitor housing 4 can have other deformations to adapt to different installation environments. In one embodiment, the end wall 41 of the capacitor housing 4 is made of a heat-conducting metal material, thereby forming a heat-conducting metal wall. Such an end wall 41 allows the heat generated by the capacitor core 6 during operation to be quickly discharged, thereby improving the heat dissipation efficiency. The peripheral wall 42 can be made of plastic. In another embodiment, the end wall 41 and the peripheral wall 42 are both made of heat-conducting metal materials, which can further improve the heat dissipation efficiency of the capacitor core 6. Any suitable heat-conducting metal material, such as aluminum or copper, can be selected to prepare the heat-conducting metal wall.

[0044] The capacitor core 6 and the busbar 5 are both fixedly arranged in the accommodating space 43 of the capacitor housing 4. Figure 6As shown, the plurality of capacitor cores 6 of the film capacitor 3 are divided into two groups, namely the first group of capacitor cores 61 and the second group of capacitor cores 62, each group of capacitor cores is arranged in an array and connected in parallel to the electrical network of the current conversion unit 1. The busbar 5 is used to connect each capacitor core 6 to other devices, such as a PCB. In the embodiment shown, the busbar 5 includes a first pole 51, a second pole 52 and a common pole 53, each of which is plate-shaped and has a plurality of junctions. The first pole 51 and the second pole 52 are arranged side by side and are closer to the end wall 41 of the capacitor housing 4 than the common pole 53. In one embodiment, the first pole 51 and the second pole 52 can be substantially in the same horizontal plane. The common pole 53 and the first pole 51 and the second pole 52 are arranged opposite to each other and spaced apart, so that a containing partition is formed between the first pole 51 and the common pole 53, and between the second pole 52 and the common pole 53. The first group of capacitor cores 61 is arranged in a compartment formed by the first pole 51 and the common pole 53, and each capacitor core 6 in the first group of capacitor cores 61 is connected to the first pole 51 at one end and to the common pole 53 at the other end. The second group of capacitor cores 62 is arranged in a compartment formed by the second pole 52 and the common pole 53, and each capacitor core 6 in the second group of capacitor cores 62 is connected to the second pole 52 at one end and to the common pole 53 at the other end. An insulating layer 54 is provided between the first pole 51 and the second pole 52 to isolate the first pole 51 from the second pole 52 to prevent the first pole 51 and the second pole 52 from forming a short circuit. The insulating layer 54 also isolates the common pole 53 from the first pole 51 and the second pole 52. One of the first pole 51 and the second pole 52 may be a positive pole, and the other may be a negative pole. The first pole 51 has a first connection end 511 extending away from the end wall 41 and out of the capacitor housing 4, the second pole 52 has a second connection end 521 extending away from the end wall 41 and out of the capacitor housing 4, and the common pole 53 has a third connection end 531 extending away from the end wall 41 and out of the capacitor housing 4. Through the first connection end 511, the second connection end 521 and the third connection end 531 of the busbar 5, the film capacitor 3 can be connected to other devices, such as a PCB.

[0045] After the capacitor core 6 and the busbar 5 are arranged in the accommodation space 43 of the capacitor housing 4, a sealing and insulating sealant 7, such as epoxy resin, is filled into the accommodation space 43. The sealant 7 encapsulates all the capacitor cores 6, separates these capacitor cores 6 from the heat-conducting metal wall of the capacitor housing 4, and prevents them from directly contacting and forming a short circuit. In the illustrated embodiment, the sealant 7 encapsulates both the capacitor core 6 and the busbar 5 in the accommodation space 43 of the capacitor housing 4, and only the first connection end 511, the second connection end 521 and the third connection end 531 of the busbar 5 are exposed. The capacitor housing 4 can be open on the side opposite to the end wall 41, and after the capacitor core 6 and the busbar 5 and other components are loaded through the open side, a flat surface is constructed on the open side by the injected sealant 7. The heat generated by the capacitor core 6 during operation is dissipated layer by layer through the sealant 7 and the heat-conducting metal wall, and the heat dissipation efficiency is significantly improved compared with the traditional housing.

[0046] In addition, a plurality of heat sinks 8 may be arranged on the end wall 41 of the capacitor housing 4, each heat sink 8 being substantially perpendicular to the end wall 41, and all heat sinks 8 may be evenly spaced and arranged on the entire surface of the end wall 41. After passing through the heat-conducting metal wall, the heat of the capacitor core 6 is further conducted by the heat sink 8 and quickly leaves the film capacitor 3. The heat sink 8 may be integrally formed with the capacitor housing 4, or may be detachably mounted on the end wall 41 of the capacitor housing 4.

[0047] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0048] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes, modifications and combinations made by any technician in the field without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A film capacitor, characterized in that: include: A capacitor housing (4) comprising an end wall (41) and a peripheral wall (42) arranged along the circumference of the end wall (41), wherein the end wall (41) and the peripheral wall (42) together enclose a receiving space (43) of the capacitor housing (4), wherein the end wall (41) is configured as a heat-conducting metal wall; A busbar (5) arranged in the accommodation space (43) of the capacitor housing (4) and having a connection end extending out of the accommodation space (43) facing away from the end wall (41); A plurality of capacitor cores (6) connected in parallel are arranged in the accommodation space (43) of the capacitor housing (4) and are each connected to the busbar (5); The sealing glue (7) is filled in the accommodating space (43) of the capacitor housing (4) and separates the plurality of capacitor cores (6) from the heat-conducting metal wall.

2. The film capacitor according to claim 1, characterized in that: The peripheral wall (42) of the capacitor housing (4) is constructed as a heat-conducting metal wall, and the sealing glue (7) separates the plurality of capacitor cores (6) from the end wall (41) and the peripheral wall (42) of the capacitor housing (4).

3. The film capacitor according to claim 1, characterized in that: The heat-conducting metal wall is an aluminum wall.

4. The film capacitor according to claim 1, characterized in that: It also comprises a plurality of heat sinks (8) arranged on the end wall (41) of the capacitor housing (4), wherein the plurality of heat sinks (8) are arranged at intervals on the entire surface of the end wall (41).

5. The film capacitor according to claim 4, characterized in that: At least a portion of the plurality of heat sinks (8) are integrally formed with the capacitor housing (4), or at least a portion of the plurality of heat sinks (8) are detachably connected to the capacitor housing (4).

6. The film capacitor according to any one of claims 1 to 5, characterized in that: The busbar (5) comprises a first pole (51) and a second pole (52) which are insulated from each other and each have a connection end, wherein each of the plurality of capacitor cores (6) is connected to the first pole (51) at its first end, and each of the plurality of capacitor cores (6) is connected to the second pole (52) at its second end.

7. The film capacitor according to claim 6, characterized in that: The first pole (51) and the second pole (52) are arranged opposite to each other and spaced apart, and the plurality of capacitor cores (6) are arranged between the first pole (51) and the second pole (52).

8. The film capacitor according to any one of claims 1 to 5, characterized in that: The busbar (5) includes a first pole (51) and a second pole (52) insulated from each other, and also includes a common pole (53), wherein the first pole (51), the second pole (52) and the common pole (53) are each formed with a connection end, wherein a first group of capacitor cores (61) among the plurality of capacitor cores (6) are each connected to the first pole (51) with their first end, and a second group of capacitor cores (62) among the plurality of capacitor cores (6) are each connected to the second pole (52) with their first end, and the first group of capacitor cores (61) and the second group of capacitor cores (62) are each connected to the common pole (53) with their second end.

9. The film capacitor according to claim 8, characterized in that: The first pole (51) and the second pole (52) are arranged side by side, the common pole (53) and the first pole (51) and the second pole (52) are arranged opposite to each other and spaced apart, wherein the first group of capacitor cores (61) is arranged between the first pole (51) and the common pole (53), and the second group of capacitor cores (62) is arranged between the second pole (52) and the common pole (53).

10. A current conversion unit, comprising: Unit housing (1); An electrical network, housed in the unit housing (1) and configured to convert the received electric current; Characterized in that the electrical network comprises the film capacitor according to any one of claims 1 to 9.

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