Busbar structure and capacitor

Abstract

This utility model discloses a busbar structure and a capacitor. The busbar structure adopts a wrapping layout for the positive and negative polarity layers of the busbar structure, which enables the conductive layers of each polarity to be more compactly stacked in space, thereby further optimizing the current path, effectively suppressing voltage spikes and oscillations during high current switching, and thus significantly reducing parasitic inductance.

Description

Technical Field

[0001] This utility model relates to the field of electronic components technology, and in particular to a busbar structure and a capacitor. Background Technology

[0002] The installed capacity and future development trend of silicon carbide inverter motors in new energy vehicles reflect the rapid penetration and potential of this technology in the electric vehicle field. With the maturity of silicon carbide technology and the reduction in cost, the application of silicon carbide inverters in new energy vehicles is rapidly increasing. Especially in high-performance models and high-voltage platforms above 800V, silicon carbide inverters have become the mainstream choice.

[0003] In existing technologies, the high inductance of traditional film capacitors used in silicon carbide inverters operating under high voltage, high power, and high frequency conditions can cause circuit oscillations during rapid switching of large currents. This not only affects system stability but may also lead to electromagnetic interference. While the inductance of busbar support capacitors in IGBT inverters is below 15nH, the inductance requirement for film capacitors in silicon carbide inverters is as low as 6–8nH. Therefore, a new busbar structure is urgently needed to address the problem of excessively high parasitic inductance in traditional capacitors during high-current switching. Utility Model Content

[0004] Embodiments of this utility model provide a busbar structure and a capacitor, which aim to solve the problem of excessive parasitic inductance when performing high current switching in traditional capacitors under the prior art.

[0005] This utility model provides a busbar structure, including a first polar conductive layer, a second polar conductive layer and an insulating layer. The first polar conductive layer and the second polar conductive layer partially overlap to form an overlapping area. The insulating layer is disposed between the first polar conductive layer and the second polar conductive layer. The second polar conductive layer includes a first surface and a second surface. The first polar conductive layer near the first surface is bent from one edge of the overlapping area and covers the second surface.

[0006] In the busbar structure provided by this utility model, the first polar conductive layer near the first surface is bent from one edge of the overlapping area along the length direction of the busbar and covers the second surface.

[0007] The busbar structure provided by this utility model also includes an AC terminal assembly disposed near the overlapping area. The AC terminal assembly includes a first AC terminal and a second AC terminal. The first AC terminal and the second AC terminal are respectively connected to the first polar conductive layer and the second polar conductive layer. A plurality of the AC terminal assemblies are disposed at intervals along the length direction of the busbar.

[0008] In the busbar structure provided by this utility model, each AC terminal is provided with two first AC terminals and one second AC terminal. The two first AC terminals are respectively disposed on both sides of the second AC terminal along the length direction of the busbar. The first AC terminal and the second AC terminal are respectively connected to the first polar conductive layer and the second polar conductive layer.

[0009] In the busbar structure provided by this utility model, a clearance hole is provided on the first polar conductive layer, and the second AC terminal passes through the clearance hole to connect to the second polar conductive layer.

[0010] In the busbar structure provided by this utility model, the first AC terminal includes a first plug-in end and a first solder end, and the second AC terminal includes a second plug-in end and a second solder end. The first solder end and the second solder end are respectively connected to the first polar conductive layer and the second polar conductive layer. The first solder end is bent in a first direction relative to the first plug-in end, and the second solder end is bent in a second direction relative to the second plug-in end. The first plug-in end and the second plug-in end extend in a direction away from the overlapping area, and the first direction is opposite to the second direction.

[0011] In the busbar structure provided by this utility model, the busbar further includes current dispersing holes, and a plurality of the current dispersing holes are evenly distributed on the first polar conductive layer and the second polar conductive layer.

[0012] In the busbar structure provided by this utility model, the first polar conductive layer and the second polar conductive layer are provided with a plurality of first core connecting parts and second core connecting parts continuously along the length direction of the busbar on the side away from the overlapping area. The first core connecting parts and the second core connecting parts are respectively used to connect the two poles of a plurality of capacitor cores arranged continuously along the direction close to the overlapping area. A plurality of current dispersing holes are provided between adjacent first core connecting parts and second core connecting parts, arranged at intervals along the direction close to the overlapping area.

[0013] The busbar structure provided by this utility model also includes a DC terminal assembly, wherein the DC terminal assembly and the AC terminal assembly are arranged far apart from each other along the length direction of the busbar.

[0014] Secondly, this utility model also discloses a capacitor, including the busbar structure as described in any of the preceding claims.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] In the technical solution of this utility model, by adopting a wrapping layout for the positive and negative polarity layers of the busbar structure, the conductive layers of each polarity are more compactly stacked in space, thereby further optimizing the current path, effectively suppressing voltage spikes and oscillations during high current switching, and thus significantly reducing parasitic inductance. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 A three-dimensional schematic diagram of the busbar structure in the existing technology's old scheme;

[0019] Figure 2 This is a three-dimensional schematic diagram of the busbar structure according to an embodiment of the present invention;

[0020] Figure 3 This is a rear view of the busbar structure according to an embodiment of the present utility model;

[0021] Figure 4 This is a cross-sectional schematic diagram A of the busbar structure according to an embodiment of the present invention;

[0022] Figure 5 B is a partially enlarged view of cross-sectional schematic diagram A of the busbar structure of this utility model embodiment;

[0023] Figure 6 This is a front view of the busbar structure according to an embodiment of the present utility model;

[0024] Figure 7 This is a bottom view of the busbar structure according to an embodiment of the present utility model;

[0025] Figure 8 This is a partially enlarged view (C) of a three-dimensional schematic diagram of the busbar structure according to an embodiment of the present invention.

[0026] Figure 9 This is a left view of the busbar structure according to an embodiment of the present utility model;

[0027] Figure 10 This is a schematic diagram of the capacitor core according to an embodiment of the present invention;

[0028] Figure 11 This is a schematic diagram of the capacitor housing according to an embodiment of the present invention;

[0029] Figure 12 This is a cross-sectional view of the capacitor according to an embodiment of the present invention;

[0030] Figure 13 This is a bottom view of the capacitor according to an embodiment of the present invention;

[0031] Figure 14 A magnetic field simulation diagram of the busbar structure in the existing technology's older scheme;

[0032] Figure 15 This is a magnetic field simulation diagram of the busbar structure according to an embodiment of the present invention.

[0033] Figure label explanation:

[0034] 10. Busbar component; 11. First polarity conductive layer; 111. Clearance hole; 113. First core connection part; 12. Second polarity conductive layer; 121. First surface; 122. Second surface; 123. Second core connection part; 13. Insulating layer; 14. Overlapping area; 15. Current dispersion hole;

[0035] 20. AC terminal assembly; 21. First AC terminal; 211. First plug-in terminal; 212. First solder terminal; 22. Second AC terminal; 221. Second plug-in terminal; 222. Second solder terminal;

[0036] 30. DC terminal assembly; 31. First DC terminal; 32. Second DC terminal;

[0037] 40. Core; 50. Housing; 60. Heat dissipation aluminum plate. Detailed Implementation

[0038] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0039] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0040] This invention provides a busbar structure designed to solve the problem of excessively high parasitic inductance during high-current switching in traditional capacitors. (Refer to...) Figures 1 to 9The busbar structure includes a first polar conductive layer 11, a second polar conductive layer 12, and an insulating layer 13. The first polar conductive layer 11 and the second polar conductive layer 12 partially overlap to form an overlap region 14. The insulating layer 13 is disposed between the first polar conductive layer 11 and the second polar conductive layer 12. The second polar conductive layer 12 includes a first surface 121 and a second surface 122. The first polar conductive layer 11 near the first surface 121 is bent from one edge of the overlap region 14 and covers the second surface 122. The first polar conductive layer 11 and the second polar conductive layer 12 are typically made of highly conductive metal materials, such as copper or silver-coated copper, to ensure good electrical conductivity. The insulating layer 13 can be made of epoxy resin composite material or other materials with good insulation and thermal properties to ensure electrical and thermal isolation between the two conductive layers. The first polar conductive layer 11 and the second polar conductive layer 12 are defined as the negative busbar and the positive busbar. The first polar conductive layer 11 and the second polar conductive layer 12 partially overlap to form an overlap region 14. At one edge of the overlap region 14, a portion of the first polar conductive layer 11 is bent using a mechanical bending device, causing it to wrap around and cover the other side of the second polar conductive layer 12. This forms a sandwich-like wrapping structure, maximizing the symmetry of the current path. The side of the second polar conductive layer 12 closest to the first polar conductive layer 11 before bending and the other side closest to the first polar conductive layer 11 after bending are defined as the first side 121 and the second side 122, respectively. During the process, the assembled busbar structure is placed in a hot-pressing fixture to compress the interlayer distance, further reducing parasitic inductance. Furthermore, after bending and assembly, appropriate surface treatment or coating can be applied to the bending area to prevent fatigue cracks at the bending point and extend the service life of the busbar.

[0041] In the technical solution of this utility model, by adopting a wrapping layout for the positive and negative polarity layers of the busbar structure, the conductive layers of each polarity are more compactly stacked in space, thereby further optimizing the current path, effectively suppressing voltage spikes and oscillations during high current switching, and thus significantly reducing parasitic inductance.

[0042] In one embodiment, reference is made to Figure 4 , Figure 5 and Figure 9The first polar conductive layer 11, close to the first surface 121, is bent from the overlapping area 14 along one edge of the busbar length direction and covers the second surface 122. Bending the first polar conductive layer 11 along one edge of the busbar length direction can minimize the length of the bending edge, reduce the performance loss of the conductive layer due to bending, and shorten the size of the bending fixture, which is convenient for production. At the same time, since other functional structural components will be set along the length direction of the busbar, bending the first polar conductive layer 11 along one edge of the busbar length direction also simplifies the structure of the busbar, making it less likely to interfere with other functional structural components.

[0043] Furthermore, referring to Figure 2 , Figure 4 , Figure 6 and Figure 7 The busbar structure also includes AC terminal assemblies 20 disposed near the overlapping area 14. Each AC terminal assembly 20 includes a first AC terminal 21 and a second AC terminal 22, which are respectively connected to the first polar conductive layer 11 and the second polar conductive layer 12. Multiple AC terminal assemblies 20 are spaced apart along the length of the busbar. Multiple AC terminal assemblies 20 are disposed at the edge of the overlapping area 14, each assembly containing a first AC terminal 21 and a second AC terminal 22. The first AC terminal 21 and the second AC terminal 22 are typically made of a highly conductive metal material, such as copper, and are precision-formed and surface-treated to ensure good conductivity and durability in electrical connections. The first AC terminal 21 is connected to the first polar conductive layer 11, typically by welding or crimping, to firmly fix the terminal to a specific point on the busbar, ensuring reliable current transmission. The second AC terminal 22 is connected to the second polar conductive layer 12, also using welding or crimping processes to achieve stable electrical contact. To ensure reliable connections and reduce parasitic inductance, the terminal connection area should be as short as possible and close to the conductive layer surface to avoid excess wires or connectors affecting the overall inductance. Multiple AC terminal assemblies 20 are spaced evenly along the length of the busbar to ensure efficient space utilization and facilitate system heat dissipation and electromagnetic compatibility. During actual assembly, according to design parameters, fixtures or tooling are used to install the AC terminals one by one into their preset positions, ensuring a tight bond to the conductive layer, followed by necessary soldering or crimping. To enhance the electrical performance of the terminal connections, conductive paste or tin plating can be applied between the terminals and the conductive layer to reduce contact resistance and improve overall conductivity.

[0044] In one embodiment, reference is made to Figure 2 , Figure 4 , Figure 6 and Figure 7Each AC terminal has two first AC terminals 21 and one second AC terminal 22. The two first AC terminals 21 are respectively located on both sides of the second AC terminal 22 along the length of the busbar. The first AC terminals 21 and the second AC terminals 22 are respectively connected to the first polarity conductive layer 11 and the second polarity conductive layer 12. The first polarity conductive layer 11 is the positive electrode, and the second polarity conductive layer 12 is the negative electrode. The second AC terminal 22 is soldered to the second polarity electrode layer. The two first AC terminals 21 are symmetrically located on both sides of the second AC terminal 22 with a certain distance between them, forming a "positive-negative-positive" sandwich structure. This achieves mutual coupling and cancellation of the magnetic fields of adjacent terminals, reduces parasitic inductance, and improves the working efficiency and stability of the inverter.

[0045] In one embodiment, reference is made to Figure 6 and Figure 8 A clearance hole 111 is formed on the first polar conductive layer 11, and the second AC terminal 22 passes through the clearance hole 111 to connect to the second polar conductive layer 12. The clearance hole 111 is formed in the middle of the first polar conductive layer 11. The clearance hole 111 can be square or circular, depending on the cross-sectional shape of the second AC terminal 22. The wall of the clearance hole 111 is mechanically chamfered and then coated with a voltage-resistant insulating varnish. The second AC terminal 22 passes through the clearance hole 111 to connect to the second polar conductive layer 12, maintaining a gap between itself and the outer wall of the clearance hole 111. The presence of the clearance hole 111 achieves zero-misalignment connection between layers, further reducing parasitic inductance.

[0046] In one embodiment, reference is made to Figure 8The first AC terminal 21 includes a first plug-in end 211 and a first solder end 212, and the second AC terminal 22 includes a second plug-in end 221 and a second solder end 222. The first solder end 212 and the second solder end 222 are respectively connected to the first polar conductive layer 11 and the second polar conductive layer 12. The first solder end 212 is bent in a first direction relative to the first plug-in end 211, and the second solder end 222 is bent in a second direction relative to the second plug-in end 221. The first plug-in end 211 and the second plug-in end 221 extend away from the overlapping area 14, and the first direction is opposite to the second direction. The first AC terminal 21 is stamped and divided into the first plug-in end 211 and the first solder end 212. Similarly, the second AC terminal 22 is divided into the second plug-in end 221 and the second solder end 222. The plug-in end refers to the end that makes an external connection, and the solder end refers to the end that is soldered to the conductive layer of the corresponding polarity. During implementation, the first welding end 212 is bent upwards by 90° relative to the first insertion end 211 on a bending machine, and the second welding end 222 is bent downwards by 90° relative to the second insertion end 221, ensuring that the two bending directions are opposite. The bending point is set at 1 / 3 of the terminal length to avoid stress concentration at the bend. After assembling the AC terminal and the conductive layer of the corresponding polarity, a hot-pressing process is performed to ensure a tight fit between the terminal and the conductive layer. The reverse bending causes the current paths of adjacent terminals to flow in opposite parallel directions, and the magnetic fields cancel each other out, reducing additional inductance.

[0047] In one embodiment, reference is made to Figure 2 , Figure 4 and Figure 7 The busbar also includes current dispersing holes 15, with multiple current dispersing holes 15 evenly distributed on the first polar conductive layer 11 and the second polar conductive layer 12. The first polar conductive layer 11 and the second polar conductive layer 12 are respectively provided with uniformly distributed circular current dispersing holes 15, forming an array. In the prior art, the core 40 connecting parts are spaced apart, while in the present invention, the core 40 connecting parts are connected, and circular current dispersing holes 15 are provided in the connected areas. When current passes through the main area of ​​the core 40 connecting part, the holes form additional current paths, which helps to evenly distribute the current density, improve the electric field distribution, reduce parasitic inductance, and enhance the thermal conductivity and electromagnetic compatibility performance of the busbar, thereby supporting the stable operation of the inverter in a high-frequency, high-current environment.

[0048] Furthermore, referring to Figure 2 , Figure 4 and Figure 7On the side of the first polar conductive layer 11 and the second polar conductive layer 12 away from the overlapping region 14, a plurality of first core connecting portions 113 and second core connecting portions 123 are continuously provided along the length direction of the busbar. The first core connecting portions 113 and the second core connecting portions 123 are respectively used to connect the two poles of a plurality of capacitor cores 40 continuously arranged along the direction close to the overlapping region 14. Between adjacent first core connecting portions 113 and second core connecting portions 123, a plurality of current dispersing holes 15 are provided at intervals along the direction close to the overlapping region 14. The overlapping region 14 extends the first polar conductive layer 11 and the second polar conductive layer along the upper and lower sides, respectively. A plurality of consecutive first core connecting portions 113 and second core connecting portions 123 are processed for the extended first polar conductive layer 11 and the second polar conductive layer, respectively. Each connecting portion has a fixed width and is correspondingly welded to the gold-plated polar end of a capacitor core 40. In the interval area between adjacent connecting portions, circular current dispersing holes 15 are arranged along the direction close to the overlapping region 14, with a fixed hole spacing, forming a regular array. During assembly, the gold-plated surfaces of the arrayed capacitor cores 40 are laser-welded to the corresponding connection parts and then solidified by hot pressing. The layout of adjacent connection parts and current dispersion holes 15 in this embodiment not only optimizes the distribution of electric field current but also improves the thermal management and electromagnetic compatibility of the busbar, thereby meeting the requirements for high performance and high stability in power electronics applications.

[0049] In one embodiment, reference is made to Figure 2 , Figure 4 , Figure 6 , Figure 7 and Figure 9 The busbar structure also includes a DC terminal assembly 30, which includes a first DC terminal 31 and a second DC terminal 32 respectively connected to the first polar conductive layer 11 and the second polar conductive layer 12. The DC terminal assembly 30 and the AC terminal assembly 20 are arranged far apart from each other along the length of the busbar. The DC terminal assembly 30 includes a first DC terminal 31 connected to the first polar conductive layer 11 and a second DC terminal 32 connected to the second polar conductive layer 12. The first DC terminal 31 is connected to the first polar conductive layer 11 by welding or mechanical clamping, and the second DC terminal 32 is connected to the second polar conductive layer 12 and is also fixed by welding or other fastening processes. To optimize the space utilization and electrical performance of the busbar, the DC terminal assembly 30 is arranged in a region far away from the AC terminal assembly 20 along the length of the busbar, that is, a certain gap is left between the AC terminals and the DC terminals, and the DC terminal assembly 30 is far apart from the AC terminal assembly 20 along the length of the busbar. This design can reduce the impact of high-frequency interference, improve the electromagnetic compatibility of the system, and facilitate subsequent heat dissipation and maintenance. To achieve good conductivity, conductive adhesive can be applied to the contact surface between the terminal and the conductive layer, or a surface plating treatment can be performed.

[0050] To further illustrate the superior performance of the busbar structure of this utility model, refer to... Figure 14 and Figure 15 The following lists the simulation test results of the old busbar structure under the prior art and the busbar structure of the present utility model embodiment.

[0051] according to Figure 14 and Figure 15 As can be seen, the magnetic field lines in the simulation diagram of the old design are randomly distributed, with a maximum magnetic field strength of 256.9 A / m. The magnetic field lines in the simulation diagram of the design in this patent are more uniformly distributed, with a maximum magnetic field strength of 155 A / m. Therefore, the busbar structure of this invention has lower parasitic inductance.

[0052] This utility model also discloses a capacitor, including the busbar structure as described in any of the above embodiments. (Refer to...) Figures 10 to 13 The capacitor comprises 24 metallized film cores 40 arranged in 3 rows and 8 columns. The gold-plated surfaces of the cores 40 are laser-welded to the corresponding connection parts of the busbar assembly 10. A heat dissipation aluminum plate 60 is embedded at the bottom of the capacitor's plastic casing 50. The heat dissipation aluminum plate 60 and the casing 50 are integrally injection molded. Specifically, molten PPS plastic is injected into a mold containing the aluminum plate for integral molding. The heat dissipation aluminum plate 60 improves heat dissipation efficiency, ensuring that it maintains an ideal temperature rise level during operation and extending its service life. After the busbar assembly 10, assembled with the cores 40, is installed into the casing 50, epoxy resin is poured in and cured in stages with increasing temperature to achieve internal sealing. In addition, to better monitor the temperature changes of the capacitor and prevent overheating and burnout, an NTC thermistor is integrated into the plastic casing.

[0053] This capacitor structure not only improves electrical performance by optimizing the geometry and layout of the busbar, but also effectively controls changes in parasitic parameters, enhancing the system's anti-interference capability and reliability. It is widely used in complex power electronic systems involving high frequency and high current, meeting the demands of modern new energy electric vehicles, inverters, and other equipment for high-performance capacitors, and possesses significant potential for widespread adoption and application.

[0054] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A busbar structure, characterized in that, It includes a first polar conductive layer, a second polar conductive layer, and an insulating layer. The first polar conductive layer and the second polar conductive layer partially overlap to form an overlapping area. The insulating layer is disposed between the first polar conductive layer and the second polar conductive layer. The second polar conductive layer includes a first surface and a second surface. The first polar conductive layer near the first surface is bent from one edge of the overlapping area and covers the second surface.

2. The busbar structure according to claim 1, characterized in that, The first polar conductive layer near the first surface is bent from one edge of the overlapping area along the length direction of the busbar and covers the second surface.

3. The busbar structure according to claim 2, characterized in that, It also includes an AC terminal assembly disposed near the overlapping area. The AC terminal assembly includes a first AC terminal and a second AC terminal. The first AC terminal and the second AC terminal are respectively connected to the first polar conductive layer and the second polar conductive layer. A plurality of the AC terminal assemblies are disposed at intervals along the length direction of the busbar.

4. The busbar structure according to claim 3, characterized in that, Each of the AC terminals is provided with two first AC terminals and one second AC terminal. The two first AC terminals are respectively located on both sides of the second AC terminal along the length direction of the busbar. The first AC terminals and the second AC terminals are respectively connected to the first polar conductive layer and the second polar conductive layer.

5. The busbar structure according to claim 4, characterized in that, A clearance hole is provided on the first polar conductive layer, and the second AC terminal passes through the clearance hole to connect to the second polar conductive layer.

6. The busbar structure according to claim 5, characterized in that, The first AC terminal includes a first plug-in terminal and a first solder terminal, and the second AC terminal includes a second plug-in terminal and a second solder terminal. The first solder terminal and the second solder terminal are respectively connected to the first polar conductive layer and the second polar conductive layer. The first solder terminal is bent in a first direction relative to the first plug-in terminal, and the second solder terminal is bent in a second direction relative to the second plug-in terminal. The first plug-in terminal and the second plug-in terminal extend in a direction away from the overlapping area, and the first direction is opposite to the second direction.

7. The busbar structure according to claim 1, characterized in that, The busbar also includes current dispersing holes, and a plurality of the current dispersing holes are evenly distributed on the first polar conductive layer and the second polar conductive layer.

8. The busbar structure according to claim 7, characterized in that, On the side of the first polar conductive layer and the second polar conductive layer away from the overlapping area, a plurality of first core connecting portions and second core connecting portions are continuously provided along the length direction of the busbar. The first core connecting portions and the second core connecting portions are respectively used to connect the two poles of a plurality of capacitor cores arranged continuously along the direction close to the overlapping area. A plurality of current dispersing holes are provided between adjacent first core connecting portions and second core connecting portions, arranged at intervals along the direction close to the overlapping area.

9. The busbar structure according to claim 3, characterized in that, It also includes a DC terminal assembly, which includes a first DC terminal and a second DC terminal respectively connected to the first polar conductive layer and the second polar conductive layer. The DC terminal assembly and the AC terminal assembly are arranged far apart from each other along the length of the busbar.

10. A capacitor, characterized in that, Includes the busbar structure as described in any one of claims 1 to 9.

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