Busbar heat dissipation structure and motor controller

Abstract

The present invention provides a busbar heat dissipation structure, addressing the technical field of heat dissipation structures for new energy vehicles and resolving the low heat dissipation efficiency of existing busbars. The structure comprises a main housing made of a thermally conductive material, containing a primary heat source and a cold source, and a busbar and a clamping assembly mounted on its top surface. The clamping assembly is capable of compressing the busbar to increase the contact area between the busbar and the main housing. The present invention is designed to achieve busbar heat dissipation, meeting the demand for high busbar heat dissipation efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat dissipation structures of new energy vehicles, and in particular relates to a heat dissipation structure of a busbar and a motor controller. Background Art

[0002] The motor controller is a core subcomponent of new energy vehicles. It can realize active control of the motor through various instructions from the electric vehicle, convert the DC power of the battery into AC power for the motor, and the motor then drives the tires to rotate, completing the entire process. In the process of converting DC power into AC power, the high-frequency switching of the internal power module itself will cause it to heat up seriously. Generally, there is a heat source on the lower side of the power module, such as a water channel, to help it dissipate heat. The heat dissipation principle in the existing technology is as follows: Figure 1 , which includes a controller 101, a power module 102, a cold source 103, and other components 104. The other components, for example, share an inner cavity of a motor controller with the power module 2, which includes capacitors and busbars.

[0003] The existing heat dissipation solution for motor controllers focuses on the heat dissipation of power modules, with less attention paid to the heat dissipation of sub-components (for example, busbars or capacitors). The water channel design is also based on the heat dissipation of power modules or power conversion devices such as MOSFETs. When setting the heat source in finite element simulation, the heat source is only injected into the power module or MOSFET.

[0004] Defects of the existing technology:

[0005] 1. Ignoring the fact that capacitor cores are prone to failure or even explosion when heated, as well as the heating of busbars and other components when subjected to excessive high voltage and high current. When the busbar heats up, it reduces the ability of carriers to pass through, resulting in a decrease in current conduction capacity, which in turn exacerbates the heating condition;

[0006] 2. If the busbar is coated, it will gradually oxidize and turn black after temperatures reach 140°C, losing its protective properties. Motor controllers often have compact internal structures, and the high temperatures on the busbar surface can burn sensitive components like circuit boards, injection molded parts, and wiring harnesses. Failure of these components can have immeasurable consequences, and in severe cases, even be life-threatening.

[0007] 3. A small number of existing motor controller solutions focus on busbars and capacitors. For example, solutions include applying silicone grease to the bottom of the capacitor, adding metal sheets, and adding bosses and gaskets, washers, or fins to the busbar side.

[0008] The above technical solutions all lead to the same goal, which is to use thermally conductive connecting materials (such as thermal grease, thermal pads, etc.) to transfer the heat of the sub-components to the metal housing of the motor controller, and then dissipate the heat through the metal housing of the motor controller. This heat dissipation solution of conduction plus natural convection does have a certain heat dissipation effect, but it ignores the fact that the metal housing of the motor controller is in the inner cavity of the new energy vehicle. For pure electric vehicles, the inner cavity ambient temperature is mainly affected by the motor, electronic control and the external environment. It is generally several tens of degrees higher than the room temperature, ranging from about 50-85°C. For hybrid vehicles, the ambient temperature is even more severe, the engine temperature is extremely high, and the ambient temperature can even reach 105°C and above. In such a high-temperature environment, even if the heat is transferred to the main housing of the motor controller and then to other low-temperature areas, the heat dissipation effect is very unsatisfactory.

[0009] Therefore, after meeting the heat dissipation needs of the main heat source of the power module or MOSFET, the current heat dissipation solution is difficult to take into account the heat dissipation needs of heat-generating components such as busbars and capacitors, and even has no heat dissipation design for them. Summary of the Invention

[0010] The purpose of the present invention is to provide a busbar heat dissipation structure to solve the technical problem of low busbar heat dissipation efficiency in existing products. The technical solution of this case has many technical benefits, as described below:

[0011] On one hand, the present invention provides a busbar heat dissipation structure, comprising a main shell made of a material with a high thermal conductivity coefficient, wherein a main heat source and a cold source are contained in the main shell, and a busbar and a clamping assembly are mounted on the top surface of the main shell, wherein:

[0012] The pressing assembly can press the busbar in the vertical direction to increase the contact area between the busbar and the main shell.

[0013] On the other hand, a motor controller is provided, which is equipped with part or all of the heat dissipation structure described above.

[0014] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0015] This case uses a clamping assembly to compress the busbar and remove the air in the gap between the busbar and the main shell. The main shell is made of a material with a high thermal conductivity coefficient. A small amount of air exists in the gap. Since the thermal conductivity of air is extremely low, at 0.023W / m·K, it will reduce the heat exchange efficiency between the two. The clamping assembly realizes the conduction and forced convection heat dissipation between the busbar and the main shell, and can actively dissipate heat by using the cold source, eliminating the traditional passive heat dissipation solution of adding thermal pads and fins. The heat dissipation efficiency is greatly improved. The heat transfer coefficient of passive heat dissipation by natural convection of air is generally 5W / m 2·K, while forced air cooling, the active heat dissipation driven by the fan, has a heat transfer coefficient of tens or even 100W / m 2 K, it can be seen that different heat exchange methods will lead to differences in the magnitude of heat exchange efficiency;

[0016] In addition, the heat dissipation design of the busbar and capacitors is taken into consideration, which can prevent the core of the capacitor in the motor controller from being damaged by breakdown when used at high temperatures. It can also prevent the busbar from having reduced overcurrent capacity at extremely high temperatures, and the surface protective coating from oxidizing and turning black, thereby losing its function of protecting the busbar. The parts surrounding the busbar (especially some heat-sensitive electronic components, such as PCB boards) and connectors can also be prevented from being damaged by high temperatures, causing the entire electric drive system to fail.

[0017] The motor controller provided in this case utilizes the existing active heat dissipation channels in the motor controller, eliminating the need for additional bosses, fins, etc. to occupy the internal installation space of the controller, thereby reducing the overall size and cost of the motor controller and reducing the already valuable space inside the car. It has great application value and significance. 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0019] Figure 1 This is a schematic diagram of the heat dissipation principle of the controller in the prior art;

[0020] Figure 2 This is a heat dissipation principle diagram of the busbar heat dissipation structure of the present invention;

[0021] Figure 3 A schematic diagram of the busbar heat dissipation structure of the present invention pressing the busbar in a rotational manner;

[0022] Figure 4 This is a three-dimensional diagram of the busbar heat dissipation structure of the present invention;

[0023] Figure 5 Schematic diagram of heat dissipation at points a and b of the busbar heat dissipation structure of the present invention;

[0024] in:

[0025] 1. Busbar; 2. Capacitor housing; 21. Capacitor; 22. Lug; 3. Main heat source; 4. Rotating part; 5. Thermal pad; 6. Main housing; 61. First step; 62. Second step; 7. Cold source; 8. Negative housing; 9. Handle. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present invention, those skilled in the art will appreciate that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0028] It should also be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. The illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0029] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that aspects can be practiced without these specific details. In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. The terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise stated, "multiple" means two or more.

[0030] like Figure 1The heat dissipation structure of the busbar 1 shown includes a main shell 6 made of a material with a high thermal conductivity coefficient, for example, made of metal or other high thermal conductivity materials. The main shell 6 contains a main heat source 3 and a cold source 7, and the busbar 1 and a clamping assembly are installed on the top surface of the main shell 6. The main heat source 3 is, for example, a chip, or a field effect tube or a transistor and its main circuit control function components. The main heat source in the actual motor controller is not necessarily a power module (3), but can also be a MOSFET or any power conversion device. The cold source 7 can be installed using the existing technology, for example, a fixed or detachable method. The present case does not improve the cold source 7, and the cold source 7 of the existing technology can be used as a heat dissipation component. The cold source 7 will not be described in detail here. The clamping assembly can clamp the busbar 1 in the vertical direction or horizontal direction to increase the contact area between the busbar 1 and the main shell 6. It should be pointed out that the cold source 7 is installed in the conventional manner. Figure 3 The direction is used as a reference, which is the compression in the vertical direction. It is not used as a specific limitation on the compression component of the forced heat exchange proposed in this case. In order to facilitate the understanding of the technical solution, the vertical direction is used as an example for explanation.

[0031] After the compression assembly compresses the busbar 1, the air in the gap between the busbar 1 and the main shell 6 is discharged, thereby increasing the contact area between the busbar 1 and the main shell 6, and making the busbar 1 tightly fit on the main shell 6. A high thermal conductivity insulating connecting material layer or pad can also be filled or installed between the busbar 1 and the main shell 6 to replace the air gap with the high thermal conductivity insulating material (the thermal conductivity of the high thermal conductivity insulating material is much higher than that of air), thereby improving the heat conduction efficiency. Under the action of the cold source 7, the busbar 1 can be heat exchanged, thereby reducing the operating temperature of the busbar 1.

[0032] Through the setting of the clamping assembly, the busbar 1 and the main shell 6 are cooled by conduction and forced convection, and the cold source 7 can be used for active heat dissipation, abandoning the traditional passive heat dissipation scheme of adding thermal pads 5 and fins. The heat dissipation efficiency is greatly improved. The heat transfer coefficient of passive heat dissipation by natural convection of air is generally 5W / m2K, while the heat transfer coefficient of active heat dissipation driven by forced air cooling and fans reaches tens or even 100W / m2K. It can be seen that different heat exchange methods will bring about differences in the magnitude of heat exchange efficiency. In addition, the heat dissipation design of the busbar 1 is taken into consideration, which can prevent the core of the capacitor 21 in the motor controller from being broken down and damaged when used at higher temperatures. It can also prevent the busbar 1 from having a reduced overcurrent capacity at extremely high temperatures, and the surface protective coating from oxidizing and blackening, thereby losing its function of protecting the busbar 1. The parts and connectors around the busbar 1 can also be prevented from being damaged by high temperatures, causing the entire electric drive system to fail.

[0033] As some embodiments provided in this case, the pressing assembly presses the busbar 1 in a rotating manner, or presses the busbar 1 in a rotational manner. The following is an explanation of the pressing in the rotational and rotational manners, see below:

[0034] Press busbar 1 by rotating

[0035] The pressing assembly includes a secondary housing and a rotating member 4 mounted on the secondary housing in a rotating manner. The secondary housing spans the busbar 1 and is connected to the main housing 6, for example, by welding or bolting. External force drives the rotating member 4 to rotate to press the busbar 1, for example, Figure 3 As shown, the rotating member 4 is a bolt that can freely pass through the auxiliary housing, with one end in contact with the busbar 1 and the other end extending out of the auxiliary housing with a protruding section. When an external force acts on the protruding section, the bolt rotates and moves in the vertical direction, thereby pressing the busbar 1 and discharging the air in the gap between the busbar 1 and the main housing 6.

[0036] Rotation method:

[0037] like Figure 4 As shown, one end of the rotating member 4 is provided with a rotating handle 9 through gear transmission. The rotation of the handle 9 drives the rotating member 4 to move in the vertical direction, thereby pressing the busbar 1.

[0038] The embodiment provided above can be further modified. For example, the end of the rotating member 4 that contacts the busbar 1 can be provided with a tower-shaped or conical structure to increase the contact area with the busbar 1, thereby increasing the pressing force and preventing air infiltration.

[0039] As some embodiments provided in this case, as the third implementation method provided in this case, the clamping assembly includes a sub-shell and a spring latch installed on the sub-shell. The spring latch can be a product of existing technology. The opening or closing of the spring latch can adjust the gap between the busbar 1 and the main shell 6. After pressing the latch, the latch presses the busbar 1. When heat dissipation is not required, press the switch of the spring latch, the latch is retracted, and the clamping of the busbar 1 is released.

[0040] In some or all of the embodiments provided above, the compression assembly also includes a thermal pad 5 made of a flexible thermally conductive material, for example, made of soft silicone filled with metal particles. The thermal pad 5 is arranged between the busbar 1 and the main shell 6 to increase the heat exchange efficiency of the busbar 1 and the main shell 6.

[0041] As some embodiments provided in this case, the capacitor 21 is cooled. For example, the main housing 6 is arranged in a stepped structure, which includes a first step 61 and a second step 62. The busbar 1 is installed on the first step 61, and the capacitor housing 2 is installed on the second step 62. A plurality of capacitors 21 are installed on the bottom surface of the capacitor housing 2 and a lug 22 is installed on the side. The lug 22 is installed with a pressure structure. The pressure structure, for example, a bolt, can press the capacitor housing 2, and the air between the capacitor housing 2 and the second step 62 is discharged. The principle is the same as that of the busbar 1 pressing component, which increases the contact area between the capacitor housing 2 and the second step 62.

[0042] The insulating thermal pad 5 is located on the lower side of the busbar 1 and the film capacitor 21 and is in a compressed state. The designed compression rate is 30%, the thickness is 1.5mm, and the thickness after compression is 1.05mm. The insulating thermal pad 5 has a single-sided adhesive backing, and the adhesive side is located close to the main shell 6. The other side is made of wear-resistant material to prevent the insulating thermal pad 5 from being cut and having insufficient insulation performance, which in turn causes device failure. The main shell 6 is made of metal aluminum, which is cheap and has good thermal conductivity. It can quickly and efficiently conduct heat to the coolant. It is generally the cavity of the motor controller, which can not only install and fix the various sub-components to protect them, but also improve the heat dissipation efficiency by changing the thickness and shape. The coolant is a medium for forced water cooling, and heat exchange with the outside world is achieved through the water inlet and outlet on the main shell 6.

[0043] The aforementioned thermal pad 5 can also be installed in this embodiment, and its shape or size is adapted to the main housing 6 .

[0044] As some embodiments provided in this case, a thermal grease layer is provided on the second step 62 to improve the heat exchange efficiency between the capacitor housing 2 and the second step 62 , or a thermal pad 5 is provided on the second step 62 .

[0045] Another aspect provides a motor controller equipped with some or all of the above heat dissipation structures. Leveraging the existing active heat dissipation channels within the motor controller, this eliminates the need for additional bosses, fins, or other components that occupy internal mounting space within the controller, reducing the overall size and cost of the motor controller, further freeing up already valuable space within the vehicle interior. This approach offers significant application value and significance.

[0046] Figure 6 Figure 1 shows the temperature sampling of the finite element simulation models. One model uses natural convection cooling with the cooling medium removed, while another uses forced convection cooling with the cooling medium dissipating the heat. The temperature differences obtained after the finite element simulation are shown in Table 1 below. It can be seen that the heat dissipation capabilities of the two different cooling methods are completely different. The proposed method of using forced convection cooling through the main heat dissipation channel significantly improves the heat dissipation effect, while the traditional cooling method is far less effective than the proposed method.

[0047] Table 1

[0048]

[0049] The above is a detailed introduction to the product provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only intended to help understand the core ideas of the present invention. It should be pointed out that, for those skilled in the art, without departing from the principles of the invention, several improvements and modifications can be made to the invention, and these improvements and modifications also fall within the scope of protection of the invention claims.

Claims

1. A heat dissipation structure of a busbar, characterized in that: It includes a main shell made of thermal conductivity material, a main heat source and a cold source are arranged in the main shell, and a busbar and a pressing assembly are installed on the top surface of the main shell, wherein: The compression assembly is capable of compressing the non-bolted portion of the busbar so that air in the gap between the non-bolted portion of the busbar and the main casing is discharged, and the busbar is pressed tightly against the main casing to increase the contact area between the busbar and the main casing; The pressing assembly includes a secondary housing and a rotating member rotatably mounted on the secondary housing, wherein the secondary housing spans the busbar and is connected to the main housing, wherein: rotating the rotating member can press the busbar; or The pressing assembly includes a secondary housing and a spring latch mounted on the secondary housing. The opening or closing of the spring latch can adjust the gap between the busbar and the main housing.

2. The heat dissipation structure according to claim 1, characterized in that: The contact end between the rotating member and the busbar is arranged in a tower-shaped structure to increase the contact area with the busbar.

3. The heat dissipation structure according to claim 1, characterized in that: The compression assembly further includes a thermal pad made of a flexible thermally conductive material, and the thermal pad is arranged between the busbar and the main shell to increase the heat exchange efficiency between the busbar and the main shell.

4. The heat dissipation structure according to claim 1, characterized in that: The main shell is arranged in a stepped structure, which includes a first step and a second step. The busbar is installed on the first step, and the capacitor shell is installed on the second step. A plurality of capacitors are installed on the bottom surface of the capacitor shell and a lug is installed on the side. The lug is installed with a pressure structure. The pressure structure can press the capacitor shell to increase the contact area between the capacitor shell and the second step.

5. The heat dissipation structure according to claim 4, characterized in that: A thermally conductive silicone grease layer is provided on the second step to improve the heat exchange efficiency between the capacitor housing and the second step.

6. The heat dissipation structure according to claim 4, characterized in that: A thermal pad is provided on the second step.

7. A motor controller, characterized in that: A heat dissipation structure according to any one of claims 1 to 6 is installed.

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