Heat conduction cooling structure and liquid cooling BDU

Abstract

The invention discloses a heat conduction cooling structure which comprises a liquid cooling plate and a copper bar of a strip-shaped plate structure. Two contacts of each relay fixedly arranged in the liquid cooling BDU are electrically and fixedly connected with a copper bar respectively, and one end, fixedly connected with the contacts, of each copper bar in the length direction is a contact connecting end; the relay is characterized in that the outer plate surface, deviating from the relay, of the contact connecting end in the thickness direction is a contact heat dissipation plane; the insulation isolation stop block is filled and fixedly arranged between the two contact connecting ends on each relay and is used for realizing electrical isolation; the outer end planes, deviating from the relay, of all the insulation isolation check blocks in the thickness direction of the contact connecting end and the contact heat dissipation plane are located on the same plane and jointly form a first plane. And the heat-conducting insulating layer is paved and covered on the first plane and is cushioned between the liquid cooling plate and the first plane. The invention further discloses a liquid cooling BDU adopting the heat conduction cooling structure. The relay contact cooling device has the advantages that efficient cooling can be achieved at the relay contact, and the like.

Description

Technical Field

[0001] This invention belongs to the field of BDU (Boiler Duct), specifically relating to a thermally conductive cooling structure and a liquid-cooled BDU. Background Technology

[0002] BDU (Battery Energy Distribution Unit) refers to the battery energy distribution unit (also known as the battery circuit breaker unit). As a dedicated distribution box for the power battery of electric vehicles, it can provide one or more functions such as pre-charging, supercharging, discharge control, circuit overload and short circuit protection, high voltage sampling, and low voltage control for the high voltage system of new energy vehicles, thereby protecting and monitoring the operation of the high voltage system.

[0003] The two contacts on the high-voltage side of the relay in the BDU frequently open and close. When they are connected, a large current is conducted, causing the contacts and the copper busbars they are connected to to heat up. With the increasing charging and discharging power of new energy vehicles and the frequent occurrence of high-power operating conditions, higher requirements are placed on the heat dissipation and operational reliability of the BDU (especially at the contacts of its core relay).

[0004] The prior art disclosure number US2025 / 0007033A1 discloses a "BDU device and battery pack" that uses liquid cooling for heat dissipation, but its technical solution still has the following shortcomings: 1. See its appendix Figure 2 As shown, in this technical solution, the copper busbar 210 generates heat, which is then transferred to the component 300 through heat exchange via the air layer between the copper busbar 210 and the component 300. The component 300 then achieves heat conduction and liquid cooling through contact with the liquid cooling plate 410. Furthermore, a vertical electrical insulating isolator is used between the two contacts of the same relay (including the copper busbar 210 and the component 300 connected to the contacts) to isolate the electric arc (correspondingly, the insulating cover plate 120 in this technical solution also has an electrical avoidance hole 124 to allow space for the vertical electrical insulating isolator (see its appendix)). Figure 3 As shown).

[0005] Due to the above structure, there is a large gap between the liquid cooling plate and the relay contacts (and copper busbars) in its technical solution, making it difficult to form a good thermal contact and heat transfer effect, resulting in a smaller thermal conduction area and lower thermal conduction efficiency.

[0006] 2. Due to the above structure, BDU products are relatively large, making it difficult to meet the requirements for small and compact products; and the overall assembly of the products is also more complex, which leads to higher product manufacturing costs.

[0007] Based on this, the applicant's primary consideration is to design a more compact thermal cooling structure and a liquid-cooled BDU with better thermal conductivity and cooling effect. Summary of the Invention

[0008] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: How to provide a more compact thermal cooling structure and a liquid-cooled BDU with better thermal conductivity and cooling effect.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A thermally conductive cooling structure includes a liquid cooling plate and a copper busbar in the form of a strip plate; In a liquid-cooled BDU, each relay has two contacts that are electrically fixedly connected to a copper busbar, with one end of the copper busbar fixedly connected to the contact along its length as the contact connection end; characterized in that: The contact connection end is a heat dissipation plane that is away from the outer plate surface of the relay in the thickness direction; It also includes an insulating isolation block that is fixedly installed between the two contact connection ends on each relay and is used to achieve electrical isolation; all the insulating isolation blocks are on the same plane as the contact heat dissipation plane and together form a first plane, away from the outer end plane of the relay in the thickness direction of the contact connection end. It also includes a thermally conductive insulating layer that is laid flat to cover the first plane and placed between the liquid cooling plate and the first plane.

[0010] A liquid-cooled BDU includes a housing and a liquid-cooled plate, the liquid-cooled plate having an inlet and an outlet for communicating with the liquid-cooled inner cavity in the liquid-cooled plate; characterized in that it further includes the aforementioned heat-conducting cooling structure.

[0011] Compared with existing technologies, the advantages of the thermally conductive cooling structure and liquid-cooled BDU of the present invention are: 1. Higher thermal conductivity and better cooling effect The heat transfer distance between the liquid cooling plate and the contact connection points on each copper busbar is equal to the thickness of the thermal insulation layer. The thickness of the thermal insulation layer is easy to control, so the heat transfer distance can be significantly shortened by controlling the thickness of the thermal insulation layer. At the same time, because the first plane includes the outer end plane of the insulating isolation block, the surface area of ​​the first plane is larger than the surface area of ​​the contact heat dissipation plane on the copper busbar. Since the thermal insulation layer also covers the first plane, the thermal contact area of ​​the thermal insulation layer must be larger than the surface area of ​​the contact heat dissipation plane, thus obtaining a larger and more effective heat conduction area and improving the heat conduction efficiency, thereby achieving a more efficient cooling effect.

[0012] 2. The tight fit between the thermally conductive insulating layer and the first plane can minimize the air cavities or gaps formed on the contact surface due to unevenness, effectively solving factors that affect thermal conductivity, such as uneven compression.

[0013] 3. The above-mentioned heat conduction and cooling structure is more streamlined and compact, occupies less space, and can help reduce the overall size of BDU, better meet the needs of compact miniaturization, and make room for more usable space for new energy vehicles. Attached Figure Description

[0014] Figure 1 This is a three-dimensional structural diagram of the liquid-cooled BDU of the present invention. Figure 2 This is a schematic diagram of the upper and lower housings of the liquid-cooled BDU of the present invention after the liquid cooling plate has been disassembled. Figure 3 This is a side view of the liquid cooling plate in the liquid-cooled BDU of the present invention. Figure 4 This is an exploded view of the liquid-cooled BDU of the present invention. Figure 5 This is a top view of the liquid-cooled BDU of the present invention (upper housing removed). Figure 6 This is a perspective view of the liquid-cooled BDU of the present invention (upper housing removed). Figure 7 This is a perspective view of the liquid-cooled BDU of the present invention (with the upper housing and thermally conductive insulating pad removed). Figure 8 This is a cross-sectional view of the lower housing and relay of the liquid-cooled BDU of the present invention. Figure 9 for Figure 8 Enlarged view of a part Figure 10 This is a partial cross-sectional view of the liquid-cooled BDU of the present invention. Figure 11 This is a schematic diagram of the relay and copper busbar components in the liquid-cooled BDU of the present invention. Figure 12 for Figure 11 Cross-sectional view of the leftmost relay and copper busbar section. The diagram is marked as follows: 0.1 First plane 1.0 upper shell: 1.01 boss 1.1 Lower housing: 1.11 L-shaped flange 1.2 Copper busbar: 1.21 Contact connection end, 1.22 Injection molded flat plate, 1.23 S-shaped bend section, 1.24 Laterally outward extending end section 2 Temperature Measuring Cloth Wiring Area 3. Relay: 3.1 Insulating isolation block, 3.2 Positioning groove 5 thermally conductive insulating pads 6. Liquid Cooling Plate: 6.1 Rectangular protrusion, 6.2 Cross-shaped through groove, 6.3 Liquid inlet pipe, 6.4 Liquid outlet pipe 8 flat bolts 9.1 NTC 12 fuses 13 compression springs Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings.

[0016] I. Thermal Conductive Cooling Structure The first embodiment, as follows Figures 1 to 12 As shown: A thermally conductive cooling structure includes a liquid cooling plate and a copper busbar in the form of a strip plate; In the liquid-cooled BDU, each of the two contacts of the relays fixedly installed in the liquid-cooled BDU is electrically connected to a copper busbar, and one end of the copper busbar fixedly connected to the contact in the length direction is the contact connection end. The contact connection end is a heat dissipation plane that is away from the outer plate surface of the relay in the thickness direction; It also includes an insulating isolation block that is fixedly installed between the two contact connection ends on each relay and is used to achieve electrical isolation; all the insulating isolation blocks are on the same plane as the contact heat dissipation plane and together form a first plane, away from the outer end plane of the relay in the thickness direction of the contact connection end. It also includes a thermally conductive insulating layer that is laid flat to cover the first plane and placed between the liquid cooling plate and the first plane.

[0017] The descriptions in this section are all existing technologies and will not be elaborated upon: The relays in a liquid-cooled BDU are arranged in pairs (usually two pairs side-by-side). One pair of relays controls the opening and closing of the positive terminal, and the other pair controls the opening and closing of the negative terminal. The other end of each copper busbar along its length serves as the external terminal for both the positive and negative high-voltage interfaces on the liquid-cooled BDU.

[0018] The thickness of the insulating isolation block is greater than or equal to the thickness of the copper busbar, and the contact surface between the insulating isolation block and the relay housing is a concave-convex mating surface.

[0019] The contact surface between the insulating isolation block and the relay housing is a concave-convex mating surface, which creates a tortuous gap between the insulating isolation block and the relay housing (in the cross-section along the width of the copper busbar). The tortuous gap has better electrical isolation effect, effectively preventing the generation of electric arcs and short circuit accidents.

[0020] As can be seen, this technical solution can achieve ideal electrical isolation within the limited space between the two contact terminals on a single relay. This helps improve the compactness of the BDU while effectively ensuring electrical safety.

[0021] When implementing, the CTI value (Comparative Tracking Index) of the insulating barrier should be greater than or equal to 400V (according to IEC 60664-1, the higher the CTI value, the smaller the creepage distance and the higher the electrical safety; for example, the preferred materials are nylon (PA), PP (partial) or PBT (the CTI of these materials can be ≥600V).

[0022] The thermally conductive insulating layer has a double-layer structure. The first layer of the double-layer structure is an insulating film for bonding and covering each of the contact heat dissipation planes, and the second layer of the double-layer structure is a thermally conductive pad that is laid flat and covers the first plane.

[0023] The above-mentioned double-layer thermally conductive and insulating layer can effectively avoid the electrical insulation risk between the contact heat dissipation planes of two adjacent contact connection ends by using the insulating film; at the same time, it can also use the insulating film to make the contact heat dissipation plane have a better waterproof sealing effect, effectively avoiding electrical faults caused by humid environments.

[0024] During implementation, the thickness of the insulating film should be less than 0.1 mm. The insulating film can be PET film (polyester film), PI film (polyimide film), PP film (polypropylene film), PTFE film (polytetrafluoroethylene film) or PEN film (polyethylene naphthalate film) with a CTI value ≥ 600V.

[0025] In practice, the thermal pad can be made from a mixture of acrylic resin and aluminum oxide.

[0026] The thickness of the thermally conductive insulating layer is 0.5-3mm.

[0027] The thermally conductive insulating layer has a simple structure and its thickness can be precisely controlled according to different customized requirements.

[0028] Each relay contact is provided with a threaded connection hole, and the contact heat dissipation surface is provided with a countersunk connection hole that is directly opposite the threaded hole; It also includes a flat bolt, the bolt section of which passes through the countersunk connection hole and is screwed into the threaded connection hole by threads, and the bolt head of the flat bolt is entirely accommodated in the countersunk connection hole.

[0029] Using flat bolts to fix the copper busbar and contacts is a simple, low-cost, and easy-to-assemble method. At the same time, using flat bolts also allows the contact heat dissipation surface to effectively form a plane, resulting in better planar contact, preventing air blockage, and improving heat conduction.

[0030] Embodiment 2 (not shown in the figure): The difference between this embodiment and the first embodiment is that: The thickness of the insulating isolation block can also be less than the thickness of the copper busbar. In this case, it is necessary to make full use of the insulating structure of the relay housing (e.g., outward protrusion) to achieve the function of electrical isolation together with the insulating isolation block.

[0031] The thermally conductive insulating layer is a single-layer structure, and the single-layer structure is a thermally conductive insulating pad.

[0032] In this way, a single-layer thermally conductive insulating pad can simultaneously serve the functions of heat conduction, insulation, and sealing, and can make the thermally conductive cooling structure more streamlined.

[0033] In practice, the thermally conductive insulating pad is made of thermally conductive insulating plastic and insulating thermally conductive filler; the thermally conductive insulating plastic is PPS, PA6, PA66, PC, PP, LCP, PPA or PEEK, and the thermally conductive filler is AL2O3 or AIN.

[0034] 3rd embodiment (not shown in the figure): The difference between this embodiment and the first embodiment is that the contact connection end of the copper busbar is welded and fixed to the contact through an intermediate connector.

[0035] 4th embodiment (not shown in the figure): The difference between this embodiment and the first embodiment is that the contact connection end of the copper busbar is integrally formed with a conductive plug, and the conductive plug is inserted into the corresponding socket on the contact with an interference fit.

[0036] II. Liquid-cooled BDU The liquid-cooled BDU includes a housing and a liquid-cooled plate, the liquid-cooled plate having an inlet and an outlet for communicating with the liquid-cooled inner cavity in the liquid-cooled plate; it also includes the heat-conducting cooling structure described in the first embodiment.

[0037] The outer casing includes an upper casing and a lower casing, both made of insulating plastic. The contact connection ends of the copper busbars on all relays are integrally formed with the lower housing through injection molding, and injection molded flat plates are formed on the horizontal perimeter of the contact connection ends. The surface of the injection molded flat plate is flush with the first plane and together they form a heat-conducting and cooling plane. The heat-conducting insulation layer covers the heat-conducting and cooling plane.

[0038] In this way, each copper busbar is integrally molded within the plastic shell of the liquid-cooled BDU, which greatly simplifies the assembly and fixing structure of the copper busbar within the shell and can effectively help improve production efficiency.

[0039] At the same time, this solution also allows the relay contacts to face downwards, and the relay contacts to be quickly fixed to the copper busbar by means of a flat bolt, thereby improving the assembly and connection efficiency between the copper busbar and the relay.

[0040] The upper and lower housings are fixedly connected by a snap-fit ​​structure. After the upper and lower housings are snapped together, the inner top surface of the upper housing can abut against the end face of all relays facing away from the contacts in the height direction, thus fixing the relays inside the housing.

[0041] By adopting this solution, the relay can be pressed tightly inside the upper and lower housings after the upper and lower housings are fastened together, thus completing the fixed installation of the relay inside the housing without the need for additional fasteners. This greatly improves the assembly efficiency of the relay inside the housing and the assembly efficiency of the housing itself.

[0042] The inner top surface of the upper housing is provided with protrusions that are directly opposite each relay. A compression spring is sleeved on the outside of each protrusion. After the upper housing and the lower housing are fastened and fixed, the inner top surface of the upper housing is elastically pressed and fixed to each relay by the compression springs.

[0043] The aforementioned protrusion and compression spring configuration allows the protrusion to limit the compression spring, while the compression spring provides elastic compression and vibration damping.

[0044] Each relay has a positioning groove at the center of its end face away from the contact in the height direction. The positioning groove is directly opposite to the protrusion and the compression spring. When the upper housing and the lower housing are fixedly connected, each of the limiting protrusions and the compression spring is inserted into the corresponding positioning groove to realize the assembly and fixation of each relay inside the housing.

[0045] The above-mentioned positioning groove, along with the protrusion and compression spring, enables the relay to achieve better elastic support and positioning while eliminating the need for bolt fixing and pre-reserved space and structural design. This simplifies assembly, allows for a more compact relay arrangement, and reduces space occupation, further enhancing the compactness of the liquid-cooled BDU structural design.

[0046] The outer bottom of the lower housing is concave and forms a receiving cavity that can accommodate the liquid cooling plate and allow the liquid cooling plate to be fixedly installed. The top surface of the receiving cavity is provided with a hollow area that allows the thermally conductive insulating layer to be fully exposed. The surface of the liquid cooling plate has a rectangular protrusion at the position opposite the hollow area for contacting and connecting with the heat-conducting cooling plane.

[0047] This allows the rectangular protrusions on the liquid cooling plate to achieve contact heat conduction with the thermally conductive insulation layer, thus better ensuring the water-cooled heat absorption and cooling effect.

[0048] Meanwhile, based on the thermally conductive cooling plane, thermally conductive insulation layer, and liquid cooling plate mounting structure of this technical solution, it can flexibly accommodate active liquid cooling, shared battery pack liquid cooling, and passive heat dissipation methods (such as air-cooled modules or heat dissipation fins), effectively solving the problem of high heat generation of BDU during fast charging and high-power charging and discharging.

[0049] The rectangular protrusions on the liquid cooling plate are multiple, each corresponding to a contact connection end of a copper busbar, and the intersection of four adjacent rectangular protrusions forms a cross-shaped through groove.

[0050] The advantages of the number of rectangular protrusions and the cross-shaped through-slot structure they form are: 1. Reduce the contact area between the liquid cooling plate and the thermally conductive insulation layer, reduce the stress on the outer shell, and reduce the risk of deformation of the outer shell structure.

[0051] 2. Optimize thermal conductivity to ensure efficient heat conduction over time, avoiding the situation where air entrapment easily occurs when a large flat surface is bonded to a thermally conductive insulating layer, which in turn increases thermal resistance and reduces thermal conductivity efficiency.

[0052] The liquid cooling plate is a strip-shaped plate structure extending in the direction of the relay arrangement inside the liquid-cooled BDU. The shell of the liquid cooling plate is provided with a coolant cavity extending in its own length direction. One end of the liquid cooling plate in the length direction is fixedly provided with an inlet interface pipe and an outlet interface pipe that are axially aligned with the length direction of the liquid cooling plate and communicate with the coolant cavity.

[0053] In this way, the inlet and outlet pipes are aligned with the flow channel, resulting in lower flow resistance, faster coolant flow, and improved heat absorption and dissipation efficiency.

[0054] A temperature measuring cloth routing area is formed between the copper busbar connected to one of the contacts on each relay and the relay. The temperature measuring cloth routing area is formed by the copper busbar extending laterally outward along the length of the relay from the contact connection end, then bending along the height of the relay, and together with the outer side of the adjacent relay. It also includes surface-mount NTCs that correspond one-to-one with each relay, and the NTCs are fixedly installed on the inner side of the horizontally outward-extending length of the copper busbar.

[0055] The NTC is fixedly installed at the point closest to the contact connection of the copper busbar. Based on the excellent thermal conductivity of the copper busbar, the true temperature of the contact can be measured more accurately, providing accurate temperature data for the control decision of the liquid-cooled BDU, thereby achieving more precise, safe and correct control.

[0056] At the same time, setting up the NTC here can better avoid interference from other heat sources, and the bending structure of the copper busbar can also form a shield for protection.

[0057] In addition, the temperature measuring cloth routing area formed between the copper busbar and the relay also forms a corridor through which the wire harness can pass along the direction of all the relays, ensuring the orderly and neat wiring of the wire harness.

[0058] See Figure 10 As shown in the red dashed box, the copper busbars on each relay, starting from the contact connection end and extending to the outer end, have an S-shaped bend and a laterally outward extending end. The S-shaped bend first extends upward along the height of the relay and then bends away from the relay. The end of the S-shaped bend extends laterally outward to form the laterally outward extending end. The entire S-shaped bend is embedded and fixed inside the lower housing by injection molding. The lower side and end of the laterally outward extending end are also embedded and fixed inside the lower housing by injection molding.

[0059] The advantages of the above-mentioned copper busbar's S-shaped bend and outwardly extending end section, which are integrally injection molded with the lower shell, are: 1. The copper busbar is integrally formed with the upper and lower housings and the part covered by it has better electrical insulation properties. It also effectively reduces the processing steps that previously required spraying insulating material on the parts of the copper busbar that do not need to be connected to the external power supply. This significantly improves the processing efficiency of the copper busbar installation process and the processing of the lower housing.

[0060] 2. The S-shaped bend section gives the copper busbar higher structural strength, and the part of the copper busbar embedded and fixed in the lower shell also forms an additional skeleton for the lower shell, which can significantly improve the structural strength of the lower shell, effectively help improve the drop resistance and impact resistance of the lower shell and the product as a whole, and significantly improve product quality.

[0061] An L-shaped retaining edge is formed on the plastic-coated position below the starting position of the contact connection end on the S-shaped bend of the copper busbar. This edge is designed to be inserted into the edges of both ends of the thermally conductive insulating layer along the width direction of the liquid cooling plate, and the cross-section is rotated at 90°.

[0062] With the above structure, the two ends of the thermally conductive insulation layer along the width direction of the liquid cooling plate can be inserted into the L-shaped baffle, thereby enabling the two ends of the thermally conductive insulation layer to completely isolate the conductive part of the copper busbar from the liquid cooling plate, achieving a reliable electrical safety protection effect.

[0063] The above are merely preferred embodiments of the present invention. It should be noted that any modifications and improvements made by those skilled in the art without departing from the present technical solution should also be considered to fall within the scope of protection claimed in this claim.

Claims

1. A thermally conductive cooling structure, comprising a liquid cooling plate and a copper busbar in the form of a strip plate; In a liquid-cooled BDU, each relay has two contacts that are electrically fixedly connected to a copper busbar, with one end of the copper busbar fixedly connected to the contact along its length as the contact connection end; characterized in that: The contact connection end is a heat dissipation plane that is away from the outer plate surface of the relay in the thickness direction; It also includes an insulating isolation block that is fixedly installed between the two contact connection ends on each relay and is used to achieve electrical isolation; all the insulating isolation blocks are on the same plane as the contact heat dissipation plane and together form a first plane, away from the outer end plane of the relay in the thickness direction of the contact connection end. It also includes a thermally conductive insulating layer that is laid flat to cover the first plane and placed between the liquid cooling plate and the first plane.

2. The thermally conductive cooling structure according to claim 1, characterized in that: The thickness of the insulating isolation block is greater than or equal to the thickness of the copper busbar, and the contact surface between the insulating isolation block and the relay housing is a concave-convex mating surface.

3. The thermally conductive cooling structure according to claim 1, characterized in that: The thermally conductive insulating layer has a double-layer structure. The first layer of the double-layer structure is an insulating film for bonding and covering each of the contact heat dissipation planes, and the second layer of the double-layer structure is a thermally conductive pad that is laid flat and covers the first plane.

4. The thermally conductive cooling structure according to claim 1, characterized in that: Each relay contact is provided with a threaded connection hole, and the contact heat dissipation surface is provided with a countersunk connection hole that is directly opposite the threaded hole; It also includes a flat bolt, the bolt section of which passes through the countersunk connection hole and is screwed into the threaded connection hole by threads, and the bolt head of the flat bolt is entirely accommodated in the countersunk connection hole.

5. A liquid-cooled BDU, comprising a housing and a liquid-cooling plate, the liquid-cooling plate having an inlet and an outlet for communicating with a liquid-cooled internal cavity within the liquid-cooling plate; characterized in that: It also includes the thermally conductive cooling structure as described in any one of claims 1 to 4.

6. The liquid-cooled BDU according to claim 5, characterized in that: The outer casing includes an upper casing and a lower casing, both made of insulating plastic. The contact connection ends of the copper busbars on all relays are integrally formed with the lower housing through injection molding, and injection molded flat plates are formed on the horizontal perimeter of the contact connection ends. The surface of the injection molded flat plate is flush with the first plane and together they form a heat-conducting and cooling plane. The heat-conducting insulation layer covers the heat-conducting and cooling plane.

7. The liquid-cooled BDU according to claim 6, characterized in that: The upper and lower housings are fixedly connected by a snap-fit ​​structure. After the upper and lower housings are snapped together, the inner top surface of the upper housing can abut against the end face of all relays facing away from the contacts in the height direction, thus fixing the relays inside the housing.

8. The liquid-cooled BDU according to claim 7, characterized in that: The inner top surface of the upper housing is provided with protrusions that are directly opposite each relay. A compression spring is sleeved on the outside of each protrusion. After the upper housing and the lower housing are fastened and fixed, the inner top surface of the upper housing is elastically pressed and fixed to each relay by the compression springs.

9. The liquid-cooled BDU according to claim 8, characterized in that: Each relay has a positioning groove at the center of its end face away from the contact in the height direction. The positioning groove is directly opposite to the protrusion and the compression spring. When the upper housing and the lower housing are fixedly connected, each of the limiting protrusions and the compression spring is inserted into the corresponding positioning groove to realize the assembly and fixation of each relay inside the housing.

10. The liquid-cooled BDU according to claim 6, characterized in that: The outer bottom of the lower housing is concave and forms a receiving cavity that can accommodate the liquid cooling plate and allow the liquid cooling plate to be fixedly installed. The top surface of the receiving cavity is provided with a hollow area that allows the thermally conductive insulating layer to be fully exposed. The surface of the liquid cooling plate has a rectangular protrusion at the position opposite the hollow area for contacting and connecting with the heat-conducting cooling plane.

11. The liquid-cooled BDU according to claim 10, characterized in that: The rectangular protrusions on the liquid cooling plate are multiple, each corresponding to a contact connection end of a copper busbar, and the intersection of four adjacent rectangular protrusions forms a cross-shaped through groove.

12. The liquid-cooled BDU according to claim 5, characterized in that: The liquid cooling plate is a strip-shaped plate structure extending in the direction of the relay arrangement inside the liquid-cooled BDU. The shell of the liquid cooling plate is provided with a coolant cavity extending in its own length direction. One end of the liquid cooling plate in the length direction is fixedly provided with an inlet interface pipe and an outlet interface pipe that are axially aligned with the length direction of the liquid cooling plate and communicate with the coolant cavity.

13. The liquid-cooled BDU according to claim 5, characterized in that: A temperature measuring cloth routing area is formed between the copper busbar connected to one of the contacts on each relay and the relay. The temperature measuring cloth routing area is formed by the copper busbar extending laterally outward along the length of the relay from the contact connection end, then bending along the height of the relay, and together with the outer side of the adjacent relay. It also includes surface-mount NTCs that correspond one-to-one with each relay, and the NTCs are fixedly installed on the inner side of the horizontally outward-extending length of the copper busbar.

14. The liquid-cooled BDU according to claim 6, characterized in that: Each relay's copper busbar, starting from the contact connection end and extending to the outer end, has an S-shaped bend and a laterally outward extending end section. The S-shaped bend first extends upward along the height of the relay and then bends away from the relay. The end of the S-shaped bend extends laterally outward to form the laterally outward extending end section. The entire S-shaped bend is embedded and fixed inside the lower housing by injection molding. The lower side and end of the laterally outward extending end section are also embedded and fixed inside the lower housing by injection molding.

15. The liquid-cooled BDU according to claim 14, characterized in that: An L-shaped retaining edge is formed on the plastic-coated position below the starting position of the contact connection end on the S-shaped bend of the copper busbar. This edge is designed to be inserted into the edges of both ends of the thermally conductive insulating layer along the width direction of the liquid cooling plate, and the cross-section is rotated at 90°.

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