Integrated heat dissipation, easy to replace core, low inductance on-board film capacitor

Abstract

The present invention discloses an integrated heat dissipation easy-to-replace core low-inductance vehicle-mounted film capacitor, which relates to the field of capacitors and includes an integrated flow channel aluminum shell, one side of the integrated flow channel aluminum shell is evenly spaced along its length direction with upper and lower rows of capacitor core placement grooves, and a film capacitor core package is placed in the capacitor core placement groove; any pole of each film capacitor core package can be detachably connected to busbar one, and the other pole can be detachably connected to busbar two; busbar one and busbar two are respectively welded with DC side terminal one and DC side terminal two, and the AC sides of busbar one and busbar two are both led out with AC side terminals. The present invention packages a single film capacitor core and connects it to the busbar through bolts and nuts, and each film capacitor core package is isolated from each other and placed in an independent capacitor core placement groove, so that damage between film capacitor cores does not affect each other, and the film capacitor core is easy to disassemble and replace, reducing the replacement and maintenance costs.

Description

Technical Field

[0001] The invention belongs to the field of capacitors, and in particular relates to a low-inductance vehicle-mounted film capacitor with integrated heat dissipation and an easily replaceable core. Background Art

[0002] As electric vehicle motor controllers develop towards high voltage, high power density, high operating frequency, efficient heat dissipation, and high integration, higher requirements are placed on the integration, high temperature resistance, and low inductance of film capacitors. In motor controllers, film capacitors play the role of smoothing and filtering, absorbing ripple, etc. Higher integration can improve the performance of film capacitors and increase the power density of motor controllers. Excessively high operating temperatures can cause thermal damage to film capacitors, leading to short circuits, which seriously affect the performance and reliability of motor controllers. The inductance on the AC side of the capacitor affects the voltage amplitude of the power module, thereby affecting the efficiency and stability of the electronic control system. Therefore, designing high temperature resistant, low inductance, integrated film capacitors has become an urgent problem to be solved in this field.

[0003] The film capacitors in the prior art usually have a high-temperature resistant heat sink at the bottom or top, which has an inefficient heat dissipation effect, low integration, and high cost. At the same time, the existing film capacitors are usually capacitors with non-detachable or non-replaceable capacitor cores, with high maintenance costs and low maintainability. In addition, the low-inductance film capacitors currently on the market are still lacking in integration, high heat dissipation, easy core replacement, low inductance, etc. For example, although some products have done well in integration and low inductance, they may still need to be improved in high heat dissipation and easy core replacement. Similarly, some products may perform well in high heat dissipation and easy core replacement, but may not be ideal in terms of integration and low inductance.

[0004] Therefore, in view of the above problems, it is necessary to propose a low-inductance vehicle-mounted film capacitor with integrated heat dissipation and easy-to-replace core. Summary of the invention

[0005] The purpose of the present invention is to provide an integrated heat dissipation, easily replaceable core, low inductance vehicle-mounted film capacitor to solve the above-mentioned problems existing in the prior art, achieve efficient heat dissipation of the film capacitor, achieve easy replacement and disassembly of the capacitor core, and achieve high integration and low inductance of the film capacitor.

[0006] To achieve the above-mentioned purpose, the present invention provides the following solution: an integrated heat dissipation, easy-to-replace core, low-inductance vehicle-mounted film capacitor, comprising an integrated flow channel aluminum shell, one side of the integrated flow channel aluminum shell is evenly spaced along its length direction with upper and lower rows of capacitor core placement grooves, and film capacitor core packages are placed in the capacitor core placement grooves; any pole of each of the film capacitor core packages can be detachably connected to busbar one, and the other pole can be detachably connected to busbar two; busbar one and busbar two are respectively welded with DC side terminal one and DC side terminal two, and AC side terminals are led out from the AC sides of busbar one and busbar two.

[0007] The above-mentioned structure of the integrated heat dissipation easy-to-replace core low-inductance vehicle-mounted film capacitor discloses at least the following beneficial effects: the film capacitor core is individually packaged, the capacitor core is connected to the busbar through bolts and nuts, and each film capacitor core package is isolated from each other and placed in an independent capacitor core placement groove, so that damage to the film capacitor cores will not affect each other, and the film capacitor core is easy to disassemble and replace, reducing the replacement and maintenance costs.

[0008] Optionally, the two rows of capacitor core placement slots are staggered and alternately distributed. The integrated flow channel aluminum shell can provide effective isolation protection to avoid chain effects caused by damage to a certain film capacitor core package.

[0009] Optionally, the integrated flow channel aluminum shell has a flow channel that bypasses the periphery of the capacitor core placement slots, one end of the flow channel is arranged on one side of the integrated flow channel aluminum shell to form a flow channel inlet, and the other end of the flow channel passes through the integrated flow channel aluminum shell to form a flow channel outlet on the other side.

[0010] The flow channel of the above structure is used to circulate the coolant. This heat dissipation method can effectively control the capacitor core to work normally within a controllable temperature range. At the same time, since the flow channel is set in the integrated flow channel aluminum shell made of aluminum alloy, the high thermal conductivity of the aluminum alloy and the coolant will effectively take away the heat loss generated by the film capacitor core, which can effectively control the temperature of the film capacitor. Since the temperature of the film capacitor core can be controlled, the high temperature resistance and high ripple current resistance of the film capacitor can be effectively improved.

[0011] Optionally, the flow channels are arranged at intervals along the width direction of the integrated flow channel aluminum housing. The multiple flow channels are evenly spaced along the width direction of the integrated flow channel aluminum housing, and each flow channel can transport coolant to achieve efficient heat dissipation.

[0012] Optionally, the flow path of the flow channel is distributed in a serpentine shape.

[0013] Optionally, the film capacitor core package includes a shell, a film capacitor core and two lead terminals, the positive and negative electrodes of the film capacitor core are respectively connected to the two lead terminals, and the film capacitor core is arranged in the shell and is insulated and sealed by a packaging material.

[0014] Optionally, the lead terminals are connected to the positive and negative ends of the film capacitor core by soldering.

[0015] Optionally, the lead terminal is connected with a rivet nut, and the busbar 1 and the busbar 2 are provided with a plurality of bolt holes corresponding to the positions of the lead terminals, and the hexagon socket bolts are passed through the bolt holes and fastened to the rivet nuts to achieve a detachable connection. When a film capacitor core is damaged, a new capacitor core can be replaced by removing the bolts and nuts, thereby effectively reducing the maintenance cost of the vehicle-mounted film capacitor and improving the maintenance efficiency.

[0016] Optionally, the connection between the AC side terminal and the busbar is provided with a bending pressure difference feature. Appropriate bending pressure difference design of the AC side terminal can effectively reduce the parasitic inductance, which is matched with the parallel design of the busbar and the capacitor core flow direction. Through simulation, under the same material conditions, compared with the unbent terminal, its parasitic inductance is reduced by 23%, so it can effectively reduce the voltage amplitude of the power module and improve the circuit protection performance.

[0017] Optionally, the AC side terminal is connected with a rivet nut. The AC side terminal is used to connect with the power module, and the rivet nut is provided to facilitate disassembly and replacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the assembly of an embodiment of the present invention;

[0020] Figure 2 Schematic diagram of the structure of busbar 1 and busbar 2 in an embodiment of the present invention;

[0021] Figure 3 It is a schematic diagram of the structure of the film capacitor core package in an embodiment of the present invention;

[0022] Figure 4 It is a schematic diagram of the structure of the film capacitor core package after removing the shell in the embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of the structure of an aluminum housing with integrated flow channel in an embodiment of the present invention;

[0024] Figure 6 It is a cross-sectional view of an aluminum housing with integrated flow channel in an embodiment of the present invention;

[0025] Among them, 1. busbar one; 11. DC side terminal one; 12. hexagon socket bolt; 13. rivet nut; 2. busbar two; 21. DC side terminal two; 22. AC side terminal; 23. bending pressure difference characteristic part; 3. film capacitor core package; 31. packaging material; 32. lead terminal; 33. shell; 34. film capacitor core; 35. welding point; 4. integrated flow channel aluminum shell; 41. flow channel inlet; 42. flow channel outlet; 43. capacitor core placement groove; 44. flow channel. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The embodiments of the present invention provide a solution for efficient heat dissipation, easy replacement, low inductance, and high integration design of vehicle-mounted film capacitors and other electronic component capacitors. In order to make the above-mentioned purposes, features, and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0028] Reference Figures 1 to 6 As shown, the present invention provides an integrated heat dissipation and easy-to-replace core low-inductance vehicle-mounted film capacitor, comprising a busbar 1, a busbar 2, a film capacitor core package 3 and an integrated flow channel aluminum shell 4; wherein, the busbar 1 and the busbar 2 are respectively welded with a DC side terminal 11 and a DC side terminal 21, and the DC side can be connected to the output end of the power battery; the AC side of the busbar 1 and the busbar 2 is provided with an AC side terminal 22, and a pressure rivet nut 13 is fixed on the AC side terminal 22, and the AC side terminal 22 is used to connect with the power module; a plurality of bolt holes are reserved on the busbar 1 and the busbar 2, which are used to connect and fix with the film capacitor core package 3 through the hexagon socket bolts 12; the integrated flow channel aluminum shell 4 is provided with regularly arranged capacitor core placement grooves 43 for placing the film capacitor core package 3, and the film capacitor core package 3 can be taken out from the capacitor core placement groove 43, and the connection method of nuts and bolts is used to improve the detachability of the capacitor. The specific structure of the assembly consisting of busbar 1, busbar 2, film capacitor core package 3 and integrated flow channel aluminum shell 4 is shown in Figure 1 shown.

[0029] In this embodiment, the shell 33 of the film capacitor core package 3 is made of PPS (polyphenylene sulfide), the packaging material 31 is made of epoxy resin, the busbar 1, busbar 2 and the lead terminal 32 are made of copper, the film capacitor core 34 is a polypropylene film capacitor, the integrated flow channel aluminum shell 4 is aluminum alloy, the hexagon socket bolt 12 is carbon steel, and the rivet nut 13 is carbon steel.

[0030] Further optimization scheme, such as Figure 2 As shown, each AC side terminal 22 is provided with a bending pressure difference feature portion 23 at the connection with the busbar (busbar 1 and busbar 2) to reduce the flow path of the terminal current and reduce the capacitor inductance. The bending pressure difference design of the AC side terminal 22, and the parallel flow of the busbar and the capacitor core current, using the principle of topological cancellation, under the same design conditions, compared with other terminal designs, this design can effectively reduce parasitic inductance.

[0031] Further optimized solution, the film capacitor core package 3 includes a shell 33, a film capacitor core 34, a lead terminal 32 and a packaging material 31; the film capacitor core 34 and two lead terminals 32 (positive terminal and negative terminal) are arranged in the shell 33 and sealed by the potting packaging material 31, and its structure is as follows Figure 3 and Figure 4 As shown, firstly, two lead terminals 32 are soldered to the positive and negative ends of the film capacitor core 34 through the solder joints 35, and then the film capacitor core 34 with the lead terminals 32 is placed in the housing 33, and finally the film capacitor core 34 is insulated and packaged by the packaging material 31. Figure 3 shown.

[0032] To further optimize the solution, in order to facilitate replacement and disassembly, a rivet nut 13 is installed on the lead terminal 32, and the rivet nut 13 can be connected and fixed with the hexagon socket bolt 12 in the busbar, so as to connect the film capacitor core package 3 with busbar 1 and busbar 2 2.

[0033] Further optimization scheme, such as Figure 5 and Figure 6As shown, a plurality of flow channels 44 are arranged in the integrated flow channel aluminum housing 4, bypassing between the capacitor core placement grooves 43. The two ends of the flow channel 44 are respectively arranged on both sides of the length direction of the integrated flow channel aluminum housing 4, and a flow channel inlet 41 and a flow channel outlet 42 are respectively formed on the side of the integrated flow channel aluminum housing 4. Specifically, the flow channel 44 is a serpentine flow channel 44, which is integrated in the aluminum housing, and a capacitor core placement groove 43 is left. The placement grooves are separated by aluminum walls, and the capacitor cores can be placed independently; while playing a role in heat dissipation, it plays a protective and isolating role for the capacitor as a whole and a single capacitor core, avoiding damage to a capacitor core and affecting other cores.

[0034] In a specific embodiment, the number of flow channels 44 is three, and the three flow channels 44 are evenly spaced along the width direction of the integrated flow channel aluminum housing 4. Each flow channel 44 can transport coolant to achieve efficient heat dissipation.

[0035] like Figure 1 As shown, the assembly sequence of the assembly of this embodiment is: first, the film capacitor core package 3 is assembled with the busbar 1 and the busbar 2; second, the film capacitor core package 3 is placed in the capacitor core placement groove 43 in the integrated flow channel aluminum shell 4.

[0036] like Figure 2 As shown, busbar 1, busbar 2, DC side terminal 11 and DC side terminal 21 are made of copper blanks by laser cutting and sheet metal bending processes; the DC side terminals are fixed to the busbars by laser welding or reflow welding; and the rivet nuts 13 on the terminals are assembled by a riveting machine.

[0037] like Figure 3 and Figure 4 As shown, the film capacitor core 34 is made by evaporation, slitting, winding, hot pressing, gold spraying and other processes; the lead terminal 32 is made by laser cutting and sheet metal bending of copper blanking; the rivet nut 13 on the lead terminal 32 is assembled by a riveting machine; the lead terminal 32 and the film capacitor core 34 are assembled by a soldering process; the shell 33 of the film capacitor core package 3 is made by machining; finally, the film capacitor core package 3 is formed by epoxy resin casting and packaging using a fixture.

[0038] like Figure 5 and Figure 6 As shown, the integrated flow channel aluminum housing 4 is made by 3D printing or machining and welding processes; the flow channel inlet 41 and the flow channel outlet 42 can be connected to the vehicle liquid cooling circulation system.

[0039] The working principle of the embodiment of the present invention is as follows:

[0040] The integrated heat dissipation easy-to-replace core low-inductance vehicle-mounted film capacitor (hereinafter referred to as film capacitor) of this embodiment is applied to the motor controller. In the motor controller, when the film capacitor is working, a large amount of ripple current will flow through the film capacitor core 34 to generate heat loss. Due to the function of the integrated flow channel aluminum housing 4, the high thermal conductivity of the aluminum alloy and the coolant will effectively take away the heat loss generated by the film capacitor core 34, and the temperature of the film capacitor can be effectively controlled.

[0041] In addition to thermal damage, in a high-frequency and high-voltage working environment, the film capacitor core 34 may also experience electrical breakdown and other phenomena, thereby causing core damage. By soldering the lead-out terminal 32 on the film capacitor core 34, the rivet nut 13 on the lead-out terminal 32 can be connected and fixed with the hexagon socket bolt 12 to connect the film capacitor core package 3 with the busbar 1 and the busbar 2 2. When a core is damaged, the film capacitor core package 3 can be disassembled and replaced.

[0042] The AC side of the film capacitor is connected to the power module, and the low inductance of the AC side terminal 22 will effectively reduce the oscillation amplitude of the power module under high frequency and high voltage operation, thereby stabilizing the voltage to protect the power module and other electronic components. By reasonably bending and breaking the AC side terminal 22, the current flow path of the AC side terminal 22 can be shortened. In addition, since the busbar of this structure is parallel to the current flow direction of the capacitor core, when a loop is formed, a busbar must be parallel and opposite to the current flow direction of the capacitor core, meeting the requirements of the topological circuit magnetic cancellation design loop. Therefore, the inductance can be effectively reduced according to the topological cancellation principle.

[0043] The embodiments of the present invention have at least the following technical effects and advantages:

[0044] 1. In terms of heat dissipation, the prior art film capacitors usually have a high temperature resistant heat dissipation device at the bottom or top, which has an inefficient heat dissipation effect. At the same time, the design of the heat dissipation device at the bottom or top increases the volume of the capacitor and the drive motor controller, which violates the development direction of the drive motor controller towards high power density, high efficiency and integration. The embodiment of the present invention integrates the aluminum housing with the flow channel 44, which is distributed in a serpentine shape and wraps the film capacitor core 34, achieving efficient heat dissipation while also playing a protective role.

[0045] 2. In terms of replaceable capacitor cores, in the existing film capacitors used in motor controllers, several to dozens of film capacitor cores 34 are often installed inside the PPS housing, connected to the busbar, and encapsulated by epoxy resin casting. However, when the capacitor is thermally damaged due to excessive temperature, the internal capacitor cores will damage each other, and replacement is difficult, so only the entire capacitor can be replaced, resulting in high replacement costs. In the embodiment of the present invention, the film capacitor core 34 is individually encapsulated, and the capacitor core is connected to the busbar through bolts and nuts. Each capacitor core is independently placed in an aluminum housing with a flow channel 44, so that the damage between the cores does not affect each other, and the cores are easy to disassemble and replace, reducing the replacement and maintenance costs.

[0046] 3. In terms of low inductance, the existing thin film capacitors used in motor controllers have changed the overall shape of the capacitor to reduce the inductance through the principle of topological cancellation. However, due to the need to consider a specific overall shape, its application in the market is not common. The embodiment of the present invention changes the shape of the busbar AC side terminal 22, bends the terminal to reduce the break difference, and based on the common square capacitors on the market, realizes the low inductance technology of the capacitor without changing the overall shape of the capacitor.

[0047] In summary, the present embodiment integrates the aluminum shell 33 and the flow channel 44 into an integrated design, which improves the heat dissipation and thermal management efficiency of the capacitor. The thin film capacitor core 34 can be wrapped and dissipated through the design of the serpentine flow channel 44, and at the same time, it also plays a better protective role. The present embodiment independently connects and assembles the busbar and the thin film capacitor core 34, which improves the detachability and replaceability and maintainability of the capacitor, and reduces the cost of repairing damaged capacitors. The present embodiment bends the busbar AC side terminal 22 with a pressure difference design, which effectively reduces the parasitic inductance of the AC side terminal 22, and protects the power module and circuit system. The present embodiment takes various factors into consideration, and the integrated design of the thin film capacitor can be beneficial to improving the power density and integration of the motor controller system.

[0048] The details not described in detail in the present invention are all conventional technical means known to those skilled in the art.

[0049] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0050] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An integrated heat dissipation and easy-to-replace core low-inductance vehicle-mounted film capacitor, characterized in that: The invention comprises an integrated flow channel aluminum shell (4), wherein one side of the integrated flow channel aluminum shell (4) is provided with upper and lower rows of capacitor core placement grooves (43) at equal intervals along its length direction, the two rows of capacitor core placement grooves (43) are staggered and alternately distributed, and thin film capacitor core packages (3) are placed in the capacitor core placement grooves (43); any pole of each of the thin film capacitor core packages (3) can be detachably connected to busbar one (1), and the other pole can be detachably connected to busbar two (2); the busbar one (1) and the busbar two (2) are respectively welded with A DC side terminal (11) and a DC side terminal (21) are provided, and the AC sides of the busbar (1) and the busbar (2) are both led out with an AC side terminal (22); the integrated flow channel aluminum housing (4) has a flow channel (44) inside that bypasses the periphery of each capacitor core placement slot (43); one end of the flow channel (44) is arranged on one side of the integrated flow channel aluminum housing (4) to form a flow channel inlet (41), and the other end of the flow channel (44) passes through the integrated flow channel aluminum housing (4) to form a flow channel outlet (42) on the other side.

2. The integrated heat dissipation and easy-to-replace core low-inductance vehicle-mounted film capacitor according to claim 1 is characterized in that: A plurality of flow channels (44) are arranged at intervals along the width direction of the integrated flow channel aluminum housing (4).

3. The integrated heat dissipation and easy-to-replace core low-inductance vehicle-mounted film capacitor according to claim 1 is characterized in that: The flow path of the flow channel (44) is distributed in a serpentine shape.

4. The integrated heat dissipation easy-to-replace core low-inductance vehicle-mounted film capacitor according to claim 1, characterized in that: The film capacitor core package (3) comprises a shell (33), a film capacitor core (34) and two lead terminals (32); the positive and negative electrodes of the film capacitor core (34) are respectively connected to the two lead terminals (32); the film capacitor core (34) is arranged in the shell (33) and is insulated and sealed by a packaging material (31).

5. The integrated heat dissipation and easy-to-replace core low-inductance vehicle-mounted film capacitor according to claim 4 is characterized in that: The lead-out terminal (32) is soldered to the positive and negative ends of the film capacitor core (34) via solder joints (35).

6. The integrated heat dissipation and easy-to-replace core low-inductance vehicle-mounted film capacitor according to claim 4 is characterized in that: The lead-out terminal (32) is connected to a rivet nut (13); the busbar 1 (1) and the busbar 2 (2) are provided with a plurality of bolt holes corresponding to the positions of the lead-out terminals (32); and the hexagon socket bolts (12) are passed through the bolt holes and fastened to the rivet nuts (13) to achieve a detachable connection.

7. The integrated heat dissipation and easy-to-replace core low-inductance vehicle-mounted film capacitor according to claim 1, characterized in that: The connection between the AC side terminal (22) and the busbar is provided with a bending and breaking difference characteristic portion (23).

8. The integrated heat dissipation easy-to-replace core low-inductance vehicle-mounted film capacitor according to claim 7, characterized in that: A rivet nut (13) is connected to the AC side terminal (22).

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