A type of automotive bus capacitor directly potted into the control box

Abstract

This invention relates to the field of bus capacitors, specifically to an automotive bus capacitor directly potted into a control box. The invention includes a control box with a baffle wall. The baffle wall and the side wall of the control box enclose an area forming a potting zone for injecting potting compound. A cooling water channel is located at the bottom of the potting zone. A first copper busbar is located at the top of the cooling water channel, with one end extending outside the control box. Several capacitor cores are located at the top of the first copper busbar and are fixedly connected to it. A second copper busbar is fixedly connected to the top of the capacitor cores, with one end extending outside the control box and the other end bent and extending into the cooling water channel's effective range. By employing the technical solution of this invention, through direct potting and the extension of the second copper busbar and efficient utilization of the cooling water channel, the bus capacitor becomes lighter, smaller, more integrated, lower cost, and higher performance.

Description

Technical Field

[0001] This invention relates to the field of bus capacitor technology, and more specifically, to an automotive bus capacitor that is directly potted into a control box. Background Technology

[0002] In motor controllers, the DC power from the battery pack serves as the input power and needs to be connected to the motor controller via a DC bus. This connection is called DC-LINK or DC support, and the capacitor used is called a bus capacitor, support capacitor, or DC-Link capacitor. Because the motor controller receives a high effective value or peak value of pulse current from the battery pack, it generates a high pulse voltage on the DC support, which the motor controller cannot withstand. Therefore, a bus capacitor is required for this connection. With the rapid rise and growth of the new energy vehicle market, higher demands are being placed on automotive bus DC support capacitors for lightweight, miniaturized, integrated, low-cost, and high-performance products.

[0003] In current technology, commercially available mass-produced automotive bus capacitors typically involve encapsulating the capacitor core within a plastic or aluminum casing before assembling it into the motor control box. This process adds an extra casing, requiring additional mounting holes and space for matching materials. Furthermore, the casing itself restricts heat dissipation, limiting the capacitor's ability to withstand high temperatures due to space constraints. Therefore, a more efficient and lightweight automotive bus capacitor that can be directly encapsulated in the control box is needed. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an automotive bus capacitor that is directly encapsulated in the control box. Through direct encapsulation and the extension of the second copper busbar and the efficient utilization of the cooling water channels, the bus capacitor becomes lighter, smaller, more integrated, lower in cost, and higher in performance.

[0005] This invention is achieved through the following technical solution: an automotive bus capacitor that is directly potted into a control box, including a control box, a baffle wall on the control box, the area surrounded by the baffle wall and the side wall of the control box forming a potting area, the potting area being used to inject potting compound, and a cooling water channel being provided at the bottom of the potting area; A first copper busbar is provided at the top of the cooling water channel. One end of the first copper busbar extends outside the control box. Several cores are provided at the top of the first copper busbar. The cores are fixedly connected to the first copper busbar. A second copper busbar is fixedly connected to the top of the cores. One end of the second copper busbar extends outside the control box. The other end of the second copper busbar is bent and extends into the working range of the cooling water channel.

[0006] Furthermore, the cooling water channel has several bends and detours.

[0007] Furthermore, the control box is provided with a controller housing area and an interface area. The first copper busbar and the second copper busbar both extend from the interface area to the outside of the control box. The core and the retaining wall are arranged in a T-shape. The controller housing area and the interface area are located on both sides of the retaining wall and each has two side walls shared with the retaining wall in two directions.

[0008] Furthermore, it also includes a connector module, which provides a wiring port. The connector module has a slot at the bottom and is snapped into the side wall shared by the controller chassis area and the retaining wall.

[0009] Furthermore, both the first and second copper busbars are provided with extension branches, which extend through the retaining wall to the controller chassis area.

[0010] Furthermore, the extension branches all extend through the connector module to the controller chassis area.

[0011] Furthermore, a first insulating layer is provided between the first copper busbar, the second copper busbar, and the control box.

[0012] Furthermore, the second copper busbar extends to one end within the cooling water channel's effective range, bends, and extends along the bottom of the core. A second insulating layer is provided between the second copper busbar, the bottom of the core, and the first copper busbar.

[0013] Furthermore, a locking protrusion is provided at the bottom of the potting area, and the locking protrusion is located on one side of the second copper busbar at the bottom of the core.

[0014] Furthermore, a heat-conducting plate is provided at the bottom of the cooling water channel, and the extended area of ​​the heat-conducting plate corresponds to the area of ​​the first copper busbar and the second copper busbar located at the bottom of the core.

[0015] The technical solution of the present invention has at least the following beneficial effects: In this solution, the bus capacitor is directly encapsulated into the control box, thus eliminating the need for the outer casing and corresponding connection structures required for bus capacitor encapsulation in conventional methods, achieving overall weight reduction for the control box and bus capacitor. The retaining wall can form a groove-shaped encapsulation area with the side wall of the control box; the bus capacitor can be placed in the encapsulation area and potting compound injected to achieve direct encapsulation.

[0016] In addition to weight reduction, because the bus capacitor has no outer casing, heat dissipation does not need to pass through the casing as a medium and can be directly dissipated. Therefore, it can share the heat dissipation structure with the control box. The cooling water channel is directly integrated into the potting area, providing a cooling source for the bus capacitor and reducing its temperature. At the same time, it can also dissipate heat for other electrical components in the control box, such as the controller, by further extending the structure, thus achieving high utilization and structural reuse of the heat dissipation structure.

[0017] The first and second copper busbars connect to both ends of the capacitor core, extending the positive and negative terminals and providing connectors for circuit wiring. Besides conducting electricity, copper itself has excellent thermal conductivity, thus enhancing the heat dissipation capacity of the bus capacitor by extending the copper structure. The second copper busbar, which originally only connected to the top of the capacitor core, is bent and extended from the top to the bottom, allowing it to also dissipate heat through the cooling water channels and transferring the heat dissipation effect to the top of the bus capacitor, achieving a uniform heat dissipation effect.

[0018] Compared with existing technologies, this solution achieves a smaller size and stronger heat dissipation effect for automotive bus capacitors through direct potting, extension of the second copper bus, and efficient utilization of cooling water channels, thus meeting market demands for lightweight, miniaturized, integrated, low-cost, and high-performance products. Attached Figure Description

[0019] Figure 1 This is an isometric view of an embodiment of the automotive bus capacitor directly encapsulated in the control box according to the present invention; Figure 2 This is an isometric view of an embodiment of the automotive bus capacitor directly encapsulated in the control box according to the present invention, after the encapsulating adhesive has been removed. Figure 3 This is a top view of an embodiment of the automotive bus capacitor directly encapsulated in the control box according to the present invention, after the encapsulating adhesive has been removed. Figure 4 This is a top view of an embodiment of the automotive bus capacitor directly encapsulated in the control box according to the present invention, after removing the second copper busbar. Figure 5 This is a top view schematic diagram of the cooling water channel in an embodiment of the automotive bus capacitor directly encapsulated in the control box according to the present invention. Figure 6 This is a cross-sectional schematic diagram of an embodiment of the automotive bus capacitor directly encapsulated in the control box according to the present invention; Figure 7 for Figure 6 An enlarged schematic diagram of the filling area in the diagram; Figure 8 The temperature thermal map of the automotive bus capacitor before improvement, which is directly potted into the control box according to the present invention. Figure 9 This is a thermal image of the automotive bus capacitor after the improvement of the method of directly potting the bus capacitor into the control box according to the present invention.

[0020] Reference numerals: 1. Control box; 2. Retaining wall; 3. Potting area; 4. Cooling water channel; 5. First copper busbar; 6. Core; 7. Second copper busbar; 8. Controller chassis area; 9. Interface area; 10. Connector module; 11. Slot; 12. Extension branch; 13. Second insulation layer; 14. Engaging protrusion; 15. Heat-conducting sheet; 401. Bending and tortuous section. Detailed Implementation

[0021] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] The following detailed description illustrates the specific implementation method: Example 1 As attached Figures 1-9As shown, an automotive bus capacitor directly potted into a control box includes a control box 1. The control box 1 is made of aluminum to reduce weight. A baffle 2 is provided on the control box 1. The area enclosed by the baffle 2 and the side wall of the control box 1 forms a potting area 3. The potting area 3 is slightly larger than the volume of the required capacitor core 6 to reduce ineffective areas. The potting area 3 is used to inject potting compound. A cooling water channel 4 is provided at the bottom of the potting area 3. The cooling water channel 4 has several bends and detours 401. The control box 1 is connected to a pump body that drives the liquid in the cooling water channel 4 to form a circulation. The pump body can be a pump body from the bus capacitor application scenario. Therefore, the control box 1 itself only needs to integrate an interface connected to the pump body. The cooling water temperature in the cooling water channel 4 is ≤65℃, and the cooling water flow rate is 8L / min.

[0025] The top of the cooling water channel 4 is provided with a first copper busbar 5. One end of the first copper busbar 5 extends to the outside of the control box 1. The top of the first copper busbar 5 is provided with several cores 6. The cores 6 are fixedly connected to the first copper busbar 5 by welding. The top of the cores 6 is welded and fixed with a second copper busbar 7. One end of the second copper busbar 7 extends to the outside of the control box 1, and the other end of the second copper busbar 7 is bent and extends into the working range of the cooling water channel 4.

[0026] The control box 1 is provided with a controller housing area 8 and an interface area 9. The first copper busbar 5 and the second copper busbar 7 both extend from the interface area 9 to the outside of the control box 1. The core 6 and the retaining wall 2 are arranged in a T-shape. The controller housing area 8 and the interface area 9 are located on both sides of the retaining wall 2 and each has two side walls in two directions that are shared with the retaining wall 2.

[0027] In this embodiment, the bus capacitor is directly encapsulated into the control box 1, thus eliminating the need for the outer shell and corresponding connection structure used in conventional bus capacitor encapsulation methods, achieving weight reduction for both the control box 1 and the bus capacitor. The retaining wall 2 forms a groove-shaped encapsulation area 3 with the side wall of the control box 1. The bus capacitor is placed in the encapsulation area 3 and encapsulated directly with potting compound. The capacitor core 6 is directly encapsulated into the control box 1, saving the need for an outer shell. Only one retaining wall 2 needs to be cast on the chassis, eliminating the need for reserved space for the capacitor core 6 shell and mounting holes, resulting in a smaller overall volume of the control box 1. Furthermore, there is no need to consider the dimensional chain assembly tolerance design between the capacitor and the chassis. Directly encapsulating the capacitor core 6 into the control box 1 eliminates scrap caused by manufacturing errors; and the elimination of bolts to fix the outer shell saves bolt costs. The overall encapsulation eliminates the failure risk that bolt tightening may cause, enhancing the overall structural strength, better conforming to design specifications, and improving the product's mechanical properties.

[0028] The core 6 and the retaining wall 2 are arranged in a T-shape. The controller chassis area 8 and the interface area 9 are located on both sides of the retaining wall 2, and each has two side walls in two directions that are shared with the retaining wall 2, which further improves the structural utilization rate, makes the overall structure more compact, reduces space waste, and further reduces weight.

[0029] Automotive bus capacitors are mostly used in environments reaching 95℃, while the melting point of the polypropylene film used for winding the cells is around 125℃. Furthermore, the design requires that the maximum temperature of the capacitor core 6 during use should not exceed 105℃. If the usage exceeds this limit, the risk of product failure will increase exponentially. Since the product carries a large current and generates significant heat, it is necessary to further reduce the temperature of the bus capacitor during operation.

[0030] Besides weight reduction, because the bus capacitor has no outer casing, heat dissipation does not need to pass through the casing and can be directly dissipated, resulting in better heat dissipation. It also allows for efficient sharing of the heat dissipation structure with the control box 1. The cooling water channel 4 is directly integrated into the potting area 3, providing a cooling source for the bus capacitor and reducing its temperature. Simultaneously, it can further extend to dissipate heat from other electrical components within the control box 1, such as the controller, achieving high utilization and structural reuse of the heat dissipation structure. The cooling water channel 4 can increase the flow area through the bends and detours 401, enhancing its heat dissipation effect.

[0031] The first copper busbar 5 and the second copper busbar 7 are connected to both ends of the capacitor core 6. Their function is to extend the positive and negative terminals of the capacitor core 6 and provide connectors, offering circuit wiring ports. Besides conducting electricity, copper itself has good thermal conductivity, thus enhancing the heat dissipation capacity of the bus capacitor by extending the copper structure. Therefore, the second copper busbar 7, which originally only needed to connect to the top of the capacitor core 6, is bent and extended from the top to the bottom of the capacitor core 6, allowing it to also dissipate heat through the cooling water channel 4 and conduct the heat dissipation effect to the top of the bus capacitor, achieving a uniform heat dissipation effect. The first copper busbar 5 is already located at the top of the cooling water channel 4, so it does not need to be extended to achieve good heat dissipation and conduction.

[0032] A temperature comparison was performed on the core 6 before and after the improvement of the cooling water channel 4 for heat dissipation, such as... Figure 8 , Figure 9 As shown, the temperature has been further reduced by approximately 4°C compared to before the improvement, resulting in a significant decrease in the internal temperature of the product. This allows the product to operate normally under more extreme conditions, and the electrical performance of the bus capacitors has been enhanced.

[0033] Compared with existing technologies, by directly potting and extending the second copper busbar 7 and making efficient use of the cooling water channel 4, the automotive bus capacitor obtained by this solution has a smaller size and a stronger heat dissipation effect, so as to meet the market's demand for lightweight, miniaturized, integrated, low-cost and high-performance products.

[0034] Example 2 The difference from the above embodiment is that it also includes a connector module 10, which provides a wiring port. The connector module 10 has a slot 11 at its bottom, and the connector module 10 is snapped into the side wall shared by the controller chassis area 8 and the retaining wall 2 through the slot 11. Both the first copper busbar 5 and the second copper busbar 7 have extension branches 12, which extend through the retaining wall 2 to the controller chassis area 8. The extension branches 12 also extend through the connector module 10 to the controller chassis area 8.

[0035] The connector module 10 provides a wiring port that can be connected to the controller signal in the controller chassis area 8 to provide a controller signal connection interface, or electrically connected to the first copper busbar 5 and the second copper busbar 7 to facilitate the expansion of circuit connections. The connector module 10 is directly snapped onto the retaining wall 2 via the slot 11. During subsequent potting, due to the snap-fit ​​connection, part of the connector module 10 is located within the potting area 3, allowing it to be directly fixed to the retaining wall 2 using potting compound, eliminating the need for a separate fixing structure.

[0036] During potting, the core 6 needs to be fixed to prevent displacement. Therefore, the first copper busbar 5 and the second copper busbar 7 extend to form branches 12. These branches 12 pass through the connector module 10 and extend to the controller chassis area 8. The branches 12 can then be electrically connected in the controller chassis area 8 for control purposes. The branches 12 and connector module 10 form a snap-fit ​​connection, effectively constraining the first and second copper busbars 5 and 7 during potting, and thus maintaining the stability of the core 6 during the potting process. Furthermore, the extension of the first and second copper busbars 5 and 7 to the controller chassis area 8 allows them to conduct heat using their thermal conductivity, transferring heat from the controller chassis area 8 and utilizing the cooling characteristics of the cooling water channel 4 to cool the controller chassis area 8.

[0037] Example 3 The difference from the above embodiment is that a first insulating layer is provided between the first copper busbar 5, the second copper busbar 7, and the control box 1. The second copper busbar 7 extends to one end within the working range of the cooling water channel 4, bends, and extends along the bottom of the core 6. A second insulating layer 13 is provided between the second copper busbar 7, the bottom of the core 6, and the first copper busbar 5. A locking protrusion 14 is provided at the bottom of the potting area 3, located on one side of the second copper busbar 7 at the bottom of the core 6. A heat-conducting plate 15 is provided at the bottom of the cooling water channel 4, and the extended area of ​​the heat-conducting plate 15 corresponds to the area of ​​the first copper busbar 5 and the second copper busbar 7 located at the bottom of the core 6.

[0038] A first insulating layer is provided between the first copper busbar 5, the second copper busbar 7, and the control box 1 to prevent short circuits caused by electrical conductivity between the first copper busbar 5, the second copper busbar 7, and the aluminum control box 1. The second copper busbar 7 extends into the effective range of the cooling water channel 4 and then extends along the bottom of the core 6 to increase the heat exchange area between the second copper busbar 7 and the cooling water channel 4. However, since the second copper busbar 7 connects to the top of the core 6, a second insulating layer 13 is required to prevent electrical conductivity between the second copper busbar 7 and the bottom of the core 6, thus preventing the positive and negative terminals of the core 6 from being connected. A portion of both the first insulating layer and the second insulating layer 13 can be filled into the reserved space during potting to form the insulation.

[0039] Since both the first copper busbar 5 and the second copper busbar 7 are partially located at the bottom of the core 6, a locking protrusion 14 is provided to prevent them from contacting each other. The locking protrusion 14 can separate the first copper busbar 5 and the second copper busbar 7. At the same time, when the core 6 is placed into the potting area 3, the locking protrusion 14 can be used for positioning to facilitate quick determination and stabilization of the position of the core 6.

[0040] The heat-conducting plate 15 can further extend the cooling effect of the cooling water channel 4, so that the bottom of the cooling water channel 4 can exchange heat through the heat-conducting plate 15. The heat-conducting plate 15 is set according to the area of ​​the first copper busbar 5 and the second copper busbar 7 at the bottom of the core 6, so as to enhance the heat exchange effect with the first copper busbar 5 and the second copper busbar 7 and improve the cooling performance.

[0041] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An automotive bus capacitor directly potted into a control box, characterized in that, Includes a control box (1), a baffle (2) is provided on the control box (1), the baffle (2) and the side wall of the control box (1) form a potting area (3), the potting area (3) is used to inject potting glue, and a cooling water channel (4) is provided at the bottom of the potting area (3). The top of the cooling water channel (4) is provided with a first copper busbar (5), one end of the first copper busbar (5) extends to the outside of the control box (1), the top of the first copper busbar (5) is provided with several cores (6), the cores (6) are fixedly connected to the first copper busbar (5), the top of the cores (6) is fixedly connected with a second copper busbar (7), one end of the second copper busbar (7) extends to the outside of the control box (1), and the other end of the second copper busbar (7) is bent and extends into the working range of the cooling water channel (4); The second copper busbar (7) extends to one end within the range of the cooling water channel (4), bends, and extends along the bottom of the core (6). A second insulating layer (13) is provided between the second copper busbar (7), the bottom of the core (6), and the first copper busbar (5). A portion of the second insulating layer (13) is formed by filling the reserved space with potting compound during potting.

2. The automotive bus capacitor directly potted into the control box according to claim 1, characterized in that, The cooling water channel (4) is provided with several bends and detours (401).

3. The automotive bus capacitor directly potted into the control box according to claim 1, characterized in that, The control box (1) is provided with a controller chassis area (8) and an interface area (9). The first copper busbar (5) and the second copper busbar (7) both extend from the interface area (9) to the outside of the control box (1). The core (6) and the retaining wall (2) are arranged in a T-shape. The controller chassis area (8) and the interface area (9) are located on both sides of the retaining wall (2) and both have two side walls that are shared with the retaining wall (2).

4. The automotive bus capacitor directly potted into the control box according to claim 3, characterized in that, It also includes a connector module (10), which is used to provide a wiring port. The connector module (10) has a slot (11) at the bottom. The connector module (10) is snapped into the side wall shared by the controller chassis area (8) and the retaining wall (2) through the slot (11).

5. The automotive bus capacitor directly potted into the control box according to claim 4, characterized in that, Both the first copper busbar (5) and the second copper busbar (7) are provided with extension branches (12), which extend through the retaining wall (2) to the controller chassis area (8).

6. The automotive bus capacitor directly potted into the control box according to claim 5, characterized in that, The extension branches (12) all pass through the connector module (10) and extend to the controller chassis area (8).

7. The automotive bus capacitor directly potted into the control box according to claim 1, characterized in that, A first insulating layer is provided between the first copper busbar (5), the second copper busbar (7), and the control box (1).

8. The automotive bus capacitor directly potted into the control box according to claim 1, characterized in that, The bottom of the potting area (3) is provided with a locking protrusion (14), which is located on one side of the second copper busbar (7) at the bottom of the core (6).

9. The automotive bus capacitor directly potted into the control box according to claim 1, characterized in that, The bottom of the cooling water channel (4) is provided with a heat-conducting plate (15), and the extended area of ​​the heat-conducting plate (15) corresponds to the area of ​​the first copper busbar (5) and the second copper busbar (7) located at the bottom of the core (6).

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