An upper cover structure of a junction box, a battery pack, and a battery system

Abstract

The application provides an upper cover structure of a junction box, a battery pack and a battery system, and relates to the technical field of power batteries. The upper cover structure of the junction box comprises an upper cover body used for being combined with a junction box base to form a seal; one side of the upper cover body facing the junction box base is provided with a mounting position used for accommodating a heating element; an inner heat conduction layer is arranged between the mounting position and the heating element, and the inner heat conduction layer can wrap at least part of the surface of the heating element; one side of the upper cover body away from the junction box base is provided with an auxiliary cold plate, the auxiliary cold plate is attached to the surface of the upper cover body, and the auxiliary cold plate is internally provided with a fluid channel used for taking away heat through the flow of a cooling medium. The protection level of the junction box can be guaranteed, and the heating element can be cooled in time, so that the system can realize higher-rate fast charging and larger-current continuous discharging, and the performance upper limit of the battery system is improved.

Description

Technical Field

[0001] This application relates to the field of power battery technology, and in particular to a junction box cover structure, a battery pack, and a battery system. Background Technology

[0002] Commercial vehicle battery systems typically consist of multiple standard battery packs. To ensure safe maintenance, each battery pack has a manual maintenance device (MSD) on its front panel, allowing manual disconnection of the high-voltage circuit during maintenance or in case of a malfunction, preventing the risk of electric shock. Simultaneously, to meet the vehicle's range and power requirements, the battery pack needs to achieve high-rate fast charging and high-current continuous discharge capabilities, placing higher demands on the heat dissipation performance of each component in the battery system. Furthermore, to ensure stable operation of the battery pack in complex and harsh environments, its casing and external components must have a high protection rating (such as IP68 / IP69K), meaning a high level of dustproof and waterproof sealing capabilities.

[0003] In existing technologies, the MSD (Medium-to-Device Adapter) is typically a separate unit located on the front panel of the battery pack, distinct from the high-voltage connector. To reduce costs and optimize space utilization, a "three-in-one" junction box solution has emerged, integrating the positive and negative high-voltage connectors with the MSD into a single unit. This junction box also consists of a base and a top cover, the latter of which can be fitted with fuses or solid copper busbars as needed. To ensure consistency with the overall protection level of the battery pack, both the separate MSD and the junction box are generally made of plastic and feature a precision structural design to achieve high airtightness. Plastic materials possess excellent insulation, corrosion resistance, and molding sealing properties, effectively meeting protection requirements.

[0004] However, existing technologies have significant drawbacks. When fuses are installed inside the MSD or junction box, the high insulation and airtightness of their plastic casing create a nearly enclosed environment for heat accumulation. During operation, especially under high current conditions, fuses generate a large amount of heat, but the extremely poor thermal conductivity of the plastic casing prevents this heat from being dissipated to the external environment in a timely and effective manner. This causes the fuse body temperature to rise continuously, leading to overheating. This overheating problem has a series of serious consequences: First, to prevent the fuse from accidentally blowing due to overheating, the system must limit the output / input current of the battery pack, severely restricting the battery pack's overcurrent capacity and making high-rate fast charging and high-current continuous discharge difficult to achieve; second, the accumulated heat is conducted to the battery cells inside the battery pack through the connecting copper busbars, adversely affecting cell lifespan.

[0005] Therefore, there is an urgent need to provide a junction box cover structure, battery pack, and battery system that can meet high protection levels while improving heat dissipation performance, thereby improving the overall performance of the battery system. Utility Model Content

[0006] This application provides a top cover structure for a junction box, a battery pack, and a battery system to solve the heat dissipation problem in current junction boxes, achieving a high protection level while improving heat dissipation performance and enhancing the overall performance of the battery system.

[0007] In a first aspect, this application provides a top cover structure for a junction box, comprising: a top cover body for sealing with a junction box base; a mounting position on the side of the top cover body facing the junction box base for accommodating a heating element; an inner heat-conducting layer disposed between the mounting position and the heating element, the inner heat-conducting layer being capable of covering at least a portion of the surface of the heating element; and an auxiliary cold plate disposed on the side of the top cover body away from the junction box base, the auxiliary cold plate being attached to the surface of the top cover body, the auxiliary cold plate having a fluid channel inside for carrying away heat through the flow of a cooling medium.

[0008] Through the above solutions, the top cover ensures a high protection rating (e.g., IP68 / IP69K) for the entire junction box. This is a fundamental prerequisite, guaranteeing the battery pack's sealing and safety in harsh environments (such as rain and water washing), preventing dust and moisture intrusion that could lead to electrical short circuits. Pre-set mounting positions allow for precise and secure installation of the heating elements inside the top cover, simplifying the assembly process and ensuring structural reliability and consistency. Gaps inevitably exist between the heating elements and the mounting positions; air, being a poor conductor of heat, severely hinders heat transfer. An inner thermally conductive layer (such as thermally conductive adhesive) effectively eliminates air, establishing an efficient initial heat conduction path. Filling the space between the heating elements and the mounting positions with thermally conductive adhesive, and ensuring the adhesive partially covers the surface of the heating elements, allows the adhesive to more fully and quickly dissipate heat from the heating elements. The auxiliary cold plate, acting as a highly efficient heat exchanger, becomes the "final outlet" for heat, rapidly carrying away heat conducted from the top cover through flowing coolant, fundamentally solving the problem of heat accumulation. The auxiliary cold plate, bonded to the surface of the top cover, allows for a very direct heat transfer path. Heat is transferred directly from the heating element, the inner heat-conducting layer, and the top cover to the auxiliary cold plate, and this bonding minimizes thermal resistance along this path. This application, without compromising the original seal, significantly reduces the operating temperature of heating elements such as fuses by constructing a synergistic heat dissipation scheme that combines optimized internal thermal conductivity with efficient external liquid cooling. With the temperature of these components reduced, the system can tolerate a larger overcurrent, enabling faster charging at higher rates and continuous discharge with greater current, fully utilizing the battery's energy and raising the performance ceiling of the battery system. This design cleverly integrates the cooling system with the junction box cover without occupying excessive space, making it ideal for application in space-constrained standard battery packs for commercial vehicles. Furthermore, the junction box cover is easier to maintain, reducing maintenance costs.

[0009] In one possible design, a perforated structure is provided at the position corresponding to the mounting position on the upper cover body, and a heat spreader is provided in the perforated structure; the heat spreader and the upper cover body are sealed together, the heat spreader is located between the inner heat-conducting layer and the auxiliary cold plate, the inner side of the heat spreader is in contact with the inner heat-conducting layer, and the outer side of the heat spreader is in contact with the auxiliary cold plate.

[0010] The above solution addresses the issue that plastic, being a poor conductor of heat, is a major obstacle to heat transfer. By creating a perforated structure, a "window" is created in the insulation wall, establishing a fast, low-thermal-resistance channel for heat transfer and removing the biggest obstacle to outward heat transfer. The vapor chamber has an extremely high equivalent thermal conductivity, far superior to metal. Embedding it into the perforated window not only fills the channel and seals the top cover, but also allows for the rapid and even diffusion of concentrated heat generated directly below the heating element across the entire vapor chamber area, preventing localized overheating. The vapor chamber is precisely positioned in the center of the heat dissipation path, with its inner side in contact with the inner heat-conducting layer, forming a sequential heat transfer path: inner heat-conducting layer, vapor chamber (heat equalization and diffusion), and auxiliary cold plate (final heat dissipation). This allows the heat generated by the heating element to be transferred directly and without loss to the vapor chamber—the core heat dissipation engine—through the inner heat-conducting layer, achieving highly efficient internal heat collection. Because the vapor chamber evenly distributes the heat, its contact with the auxiliary cooling plate is no longer an inefficient "point-to-point" heat exchange, but a highly efficient "large-area to large-area" heat exchange, maximizing the utilization of the auxiliary cooling plate's full heat dissipation capacity. The vapor chamber makes the heat flow distribution more uniform, avoiding localized overheating of the auxiliary cooling plate, making the liquid cooling system's workload more stable, resulting in better overall system thermal management and a longer lifespan.

[0011] In one possible design, a stepped structure is set around the hollow structure, and the heat dissipation plate is set on the stepped structure. The stepped structure provides an installation position for the heat spreader, allowing for quick and accurate positioning during installation, simplifying the assembly process and improving production efficiency. The stepped structure provides vertical support (perpendicular to the main surface of the upper cover), ensuring the heat spreader is securely embedded in the upper cover, preventing displacement under vibration or impact, and enhancing the product's mechanical reliability, making it particularly suitable for the harsh operating conditions of commercial vehicles. Furthermore, the flat stepped surface provides an ideal contact plane for sealing between the heat spreader and the upper cover (e.g., applying sealant or placing a sealing ring), helping to form a uniform clamping force and ensuring reliable sealing, thereby guaranteeing a high overall protection rating (IP68 / IP69K).

[0012] In one possible design, a thermal pad is placed between the heat spreader and the auxiliary cold plate.

[0013] Even with precision machining of the surfaces of the vapor chamber and auxiliary cold plate, microscopic air gaps still exist using the above-described method. The thermal pad can fill these tiny gaps, effectively eliminating air (a poor conductor of heat), significantly reducing the contact thermal resistance between the two and improving heat transfer efficiency. The thermal pad typically possesses good compressibility and elasticity, absorbing dimensional and assembly tolerances between the vapor chamber and auxiliary cold plate, ensuring good contact across different production batches and assemblies. Simultaneously, its elasticity can cushion vibrations during vehicle operation, preventing overheating due to poor contact caused by vibration. Furthermore, the thermal pad has excellent insulation properties, providing an additional electrical isolation safety barrier while conducting heat efficiently, preventing accidental electrical short circuits between the vapor chamber (usually metal) and the auxiliary cold plate (usually metal).

[0014] In one possible design, a piping structure is also included, which connects the auxiliary cold plate and the main liquid cooling plate of the battery pack housing to connect the fluid channels of the auxiliary cold plate with the coolant circuit of the main liquid cooling plate of the battery pack housing.

[0015] Through the above solution, the piping structure design integrates the local heat dissipation system of the junction box with the main cooling system of the battery pack, achieving unified and coordinated thermal management of the entire battery pack (including cells and external electrical components), simplifying the system architecture. The existing powerful heat dissipation capacity of the main liquid cooling plate of the battery pack (such as large-area heat sinks and fans) can be utilized to dissipate heat from the junction box, resulting in a large coolant circulation flow, high heat dissipation efficiency, and a more uniform temperature field throughout the system. Furthermore, there is no need to equip the junction box with a separate cooling system (such as a water pump or radiator), making full use of existing resources, significantly reducing costs and system complexity, while also reducing potential failure points and facilitating maintenance.

[0016] In one possible design, the inner thermally conductive layer is made of thermally conductive adhesive.

[0017] The above method utilizes a paste-like consistency in the thermally conductive adhesive before curing, which allows it to fully fill all irregular gaps between the heating element (such as a fuse) and the mounting position, achieving a perfect fit and minimizing contact thermal resistance. After curing, the thermally conductive adhesive possesses a certain bonding strength, which can assist in fixing the heating element and enhance its stability under vibration. The thermally conductive adhesive typically has high insulation properties, providing additional electrical insulation protection for the heating element while conducting heat, and preventing moisture intrusion, thus improving reliability. In one possible design, the heating element is a fuse or a copper busbar.

[0018] The above solution addresses the issue of overheating fuses limiting battery pack current capacity. The junction box's top cover design effectively dissipates heat, ensuring proper fuse operation and unlocking the potential for fast charging and continuous high-current discharge. Furthermore, the top cover design also effectively controls the temperature of the copper busbars, improving the long-term reliability of the system, as high currents also generate heat. Secondly, this application provides a battery pack, including a housing and standard battery cells housed within the housing. A junction box is provided on the front panel of the housing, and the junction box includes the cover structure of any of the junction boxes in the first aspect. By applying this advanced top cover heat dissipation structure, the battery pack can achieve faster charging rates and continuous discharge with larger currents, thereby improving the overall vehicle operating efficiency. It effectively prevents fault risks caused by overheating inside the junction box (such as accelerated fuse aging and decreased insulation performance), reduces the potential risk of thermal runaway propagation, and extends the battery pack's lifespan. It ensures that the battery pack maintains its high IP68 / IP69K protection standard while achieving efficient heat dissipation, adapting to various harsh environments.

[0019] In one possible design, the junction box is a three-in-one structure that integrates the positive connector, the negative connector, and the manual maintenance device (MSD) into one unit.

[0020] The above solution concentrates the heat-generating points of multiple high-current paths into a structure with efficient heat dissipation, achieving unified management of heat in the high-voltage connection area and resulting in better heat dissipation. Thirdly, this application provides a battery system comprising multiple battery packs, at least one of which is the battery pack of the second aspect.

[0021] The beneficial effects of the battery system provided in the third aspect and the various possible designs of the third aspect can be found in the first aspect and the various possible implementations of the first aspect, and will not be repeated here.

[0022] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific implementation methods of this application are described below. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a junction box structure provided in one embodiment of this application.

[0025] Figure 2 This is a schematic diagram of the top cover structure of a junction box provided in one embodiment of this application.

[0026] Figure 3 This is a schematic diagram of the hollow structure in the top cover structure of the junction box provided in one embodiment of this application.

[0027] Figure 4 for Figure 2 The top view of the junction box provided in the image.

[0028] Figure 5 for Figure 4 A cross-sectional view along the AA1 direction.

[0029] Figure 6 for Figure 4 A cross-sectional view along the BB1 ​​direction.

[0030] Explanation of reference numerals in the attached figures: 10. Junction box; 100. Top cover body; 101. Mounting position; 102. Partition; 110. Inner heat-conducting layer; 120. Auxiliary cold plate; 121. Fluid channel; 130. Heat spreader; 131. Hollow structure; 132. Stepped structure; 140. Heat-conducting pad; 150. Piping structure; 200. Junction box base; 300. Heating element. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0033] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists, A and B exist simultaneously, or B exists. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0035] The directional terms appearing in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. For example, in the description of this application, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures. They are only for the convenience of describing this application and 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 this application.

[0036] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0037] In the description of this application, unless otherwise stated, "multiple" means two or more (including two), and similarly, "multiple groups" means two or more (including two groups).

[0038] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, "connection" or "joining" in mechanical structures can refer to a physical connection, such as a fixed connection, for example, a connection fixed by a partition, such as a connection fixed by screws, bolts, or other partitions; a physical connection can also be a detachable connection, such as a snap-fit ​​or interlocking connection; a physical connection can also be an integral connection, such as a connection formed by welding, bonding, or integral molding. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] As the background technology shows, current junction boxes have the problem of not being able to simultaneously achieve high protection level and heat dissipation performance. This may lead to the output / input current inside the battery pack, which severely restricts the battery pack's overcurrent capacity, making it difficult to achieve high-rate fast charging and high-current continuous discharge. Secondly, the accumulated high heat will be conducted to the battery cells inside the battery pack through the connecting copper busbar, which will have an adverse effect on the life of the battery cells.

[0040] In view of this, embodiments of this application provide a top cover structure for a junction box, a battery pack, and a battery system. The top cover structure of the junction box includes a top cover body for sealing with a junction box base. The side of the top cover body facing the junction box base has a mounting position for accommodating a heating element. An inner heat-conducting layer is provided between the mounting position and the heating element, capable of covering at least a portion of the surface of the heating element. An auxiliary cold plate is provided on the side of the top cover body facing away from the junction box base, the auxiliary cold plate being attached to the surface of the top cover body. The auxiliary cold plate has fluid channels inside for carrying away heat through the flow of a cooling medium. This allows heat to be transferred sequentially from the heating element through the inner heat-conducting layer to the auxiliary cold plate, ensuring the protection level of the junction box while enabling timely cooling of the heating element. This allows the system to achieve higher-rate fast charging and higher-current continuous discharge, fully utilizing the battery's energy and improving the performance ceiling of the battery system. To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0041] Figure 1 This is a schematic diagram of the junction box 10 provided in this embodiment. Figure 2 This is a schematic diagram of the upper cover structure of the junction box 10 provided in this embodiment. Figure 3 This is a schematic diagram of the hollow structure 131 in the upper cover structure of the junction box 10 provided in this embodiment. Please refer to the reference. Figures 1 to 3 This application provides a top cover structure for a junction box 10, including a top cover body 100, an inner heat-conducting layer 110, and an auxiliary cold plate 120.

[0042] In this embodiment, the junction box 10 includes a junction box base 200 and an upper cover body 100. The upper cover body 100 is used to cover the junction box base 200 to form a sealed cavity. Components such as a positive connector, a negative connector, and a manual maintenance device (MSD) can be installed in the cavity.

[0043] In this embodiment, the upper cover body 100 has a mounting position 101 on the side (inner side) facing the junction box base 200, which is used to accommodate the heating element 300. An inner heat-conducting layer 110 is provided between the mounting position 101 and the heating element 300, which can cover at least part of the surface of the heating element 300. An auxiliary cold plate 120 is provided on the side of the upper cover body 100 away from the junction box base 200. The auxiliary cold plate 120 is attached to the surface of the upper cover body 100, and a fluid channel 121 is provided inside the auxiliary cold plate 120 for carrying away heat through the flow of the cooling medium.

[0044] Through the above embodiments, the top cover body 100 ensures a high protection level (e.g., IP68 / IP69K) for the junction box 10 as a whole. This is a fundamental prerequisite, ensuring the sealing and safety of the battery pack in harsh environments (e.g., rain, water washing), preventing dust and moisture intrusion that could lead to electrical short circuits. The pre-set mounting position 101 allows the heating element 300 to be precisely and securely installed inside the top cover, simplifying the assembly process and ensuring structural reliability and consistency. Gaps inevitably exist between the heating element 300 and the mounting position 101; air, being a poor conductor of heat, severely hinders heat transfer. The inner thermally conductive layer 110 (e.g., thermally conductive adhesive) effectively eliminates air, establishing an efficient initial heat conduction path. Filling the space between the heating element 300 and the mounting position 101 with thermally conductive adhesive, and ensuring that the adhesive partially covers the surface of the heating element 300, allows the adhesive to more fully and quickly dissipate heat from the heating element 300. The auxiliary cooling plate 120, acting as a highly efficient heat exchanger, serves as the "final outlet" for heat, rapidly carrying away heat conducted from the top cover through flowing coolant, fundamentally solving the problem of heat accumulation. The auxiliary cooling plate 120's attachment to the surface of the top cover body 100 ensures a very direct heat transfer path, with heat transferred directly from the heating element 300, the inner thermally conductive layer 110, and the top cover body 100 to the auxiliary cooling plate 120. This attachment minimizes thermal resistance along this path. Without compromising the original seal, this application significantly reduces the operating temperature of heating elements such as fuses 300 by constructing a synergistic heat dissipation scheme combining optimized internal thermal conductivity and efficient external liquid cooling. With the temperature of heating elements such as fuses 300 reduced, the system can tolerate a larger overcurrent, thereby achieving higher-rate fast charging and continuous discharge with a larger current, fully utilizing the battery's energy and increasing the performance ceiling of the battery system. This design cleverly integrates the cooling system with the top cover of the junction box 10 without taking up too much extra space. It is very suitable for application in standard battery packs for commercial vehicles where space is limited. In addition, the top cover of the junction box 10 is easier to maintain, reducing maintenance costs.

[0045] In this embodiment, a partition 102 may also be provided on the inner side of the upper cover body 100 for electrical isolation between internal components, such as separating the internal positive connector, negative connector and heating element 300.

[0046] Figure 4 for Figure 2 A top view of junction box 10 provided in the image. Figure 5 for Figure 4 A cross-sectional view along the AA1 direction. Figure 6 for Figure 4 A sectional view along the BB1 ​​direction. Please refer to... Figures 3 to 6 In this embodiment, a hollow structure 131 is provided on the upper cover body 100 at the position corresponding to the mounting position 101, and a heat spreader 130 is provided at the hollow structure 131; the heat spreader 130 and the upper cover body 100 are sealed together, the heat spreader 130 is located between the inner heat-conducting layer and the auxiliary cold plate 120, the inner side of the heat spreader 130 is in contact with the inner heat-conducting layer 110, and the outer side of the heat spreader 130 is in contact with the auxiliary cold plate 120.

[0047] In the above embodiments, plastic is a poor conductor of heat and a major obstacle in the heat transfer path. By setting the hollow structure 131, it is equivalent to opening a "window" in the heat insulation wall, establishing a fast channel with low thermal resistance for heat, and removing the biggest obstacle to heat transfer outward. The effective thermal conductivity of the heat spreader 130 is extremely high, far superior to that of metal. Embedding it into the hollow window not only fills the channel to achieve the sealing function of the upper cover body 100, but also enables the concentrated heat generated directly below the heating element 300 to be quickly and evenly diffused to the entire area of ​​the heat spreader 130, avoiding local high temperatures. The heat spreader 130 is precisely placed in the middle of the heat dissipation path, and the inner side of the heat spreader 130 is in contact with the inner heat-conducting layer 110, forming a path in which the inner heat-conducting layer 110, the heat spreader 130 (heat spreader, diffusion), and the auxiliary cold plate 120 (final heat dissipation) are transferred sequentially. This allows the heat generated by the heating element 300 to be transferred directly and without loss to the core heat dissipation engine, the vapor chamber 130, through the inner heat-conducting layer 110, achieving efficient heat collection from within. Since the vapor chamber 130 evenly distributes the heat, its contact with the auxiliary cold plate 120 is no longer an inefficient "point-to-point" heat exchange, but a highly efficient "large-area to large-area" heat exchange, maximizing the utilization of the auxiliary cold plate 120's full heat dissipation capacity. The vapor chamber 130 makes the heat flow distribution more uniform, avoiding localized overheating of the auxiliary cold plate 120, resulting in a more stable workload for the liquid cooling system, better overall system thermal management, and a longer lifespan.

[0048] In this embodiment, the inner thermal conductive layer 110 is a thermally conductive adhesive.

[0049] Through the above embodiments, the thermally conductive adhesive, before curing, is in a paste form, which can fully fill all irregular gaps between the heating element 300 (such as a fuse) and the mounting position 101, achieving complete adhesion and minimizing contact thermal resistance. After curing, the thermally conductive adhesive has a certain bonding strength, which can play a supporting role in fixing the heating element 300 and enhancing its stability in vibration environments. The thermally conductive adhesive typically has high insulation properties, providing additional electrical insulation protection for the heating element 300 while conducting heat, and preventing moisture intrusion, thus improving reliability. In this embodiment, the heating element 300 is a fuse or a copper busbar.

[0050] Through the above embodiments, overheating of the fuse will limit the overcurrent capacity of the battery pack. The design of the top cover structure of the junction box 10 enables effective heat dissipation, thereby ensuring the normal operation of the fuse and releasing the potential for fast charging and continuous high-current discharge.

[0051] High currents also generate heat when passing through the copper busbar. The design of this top cover structure can effectively control the temperature of the copper busbar and improve the long-term reliability of the system.

[0052] Please continue to refer to this. Figure 3 In this embodiment, a stepped structure 132 is provided around the hollow structure 131, and the heat dissipation plate 130 is provided on the stepped structure 132. In this embodiment, the material of the heat spreader 130 can be a metal plate or a flat metal plate with a vacuum cavity inside (copper is a commonly used material).

[0053] The inner wall of the heat spreader 130 can be equipped with a special capillary structure and filled with a small amount of working fluid (such as water, methanol, etc.) to achieve cooling and heat transfer.

[0054] Through the above embodiments, the stepped structure 132 provides a mounting position 101 for the heat spreader 130, allowing for quick and accurate positioning of the heat spreader 130 at this mounting position 101 during installation, simplifying the assembly process and improving production efficiency. The stepped structure 132 provides vertical support (perpendicular to the large surface direction of the upper cover body 100), enabling the heat spreader 130 to be securely embedded in the upper cover body 100, preventing displacement under vibration or impact conditions, and improving the mechanical reliability of the product, making it particularly suitable for the harsh operating conditions of commercial vehicles. Furthermore, the flat stepped surface provides an ideal contact plane for sealing between the heat spreader 130 and the upper cover body 100 (such as applying sealant or placing a sealing ring), helping to form a uniform clamping force, ensuring reliable sealing, and thus guaranteeing a high overall protection level (IP68 / IP69K).

[0055] In this embodiment, a heat-conducting pad 140 is provided between the heat spreader 130 and the auxiliary cold plate 120.

[0056] Through the above embodiments, even though the surfaces of the heat spreader 130 and the auxiliary cold plate 120 are precision-machined, microscopically uneven air gaps still exist. The thermally conductive pad 140 can fill these tiny gaps, effectively eliminating air (a poor conductor of heat), significantly reducing the contact thermal resistance between the two, and improving heat conduction efficiency. The thermally conductive pad 140 typically has good compressibility and elasticity, which can absorb the dimensional and assembly tolerances between the heat spreader 130 and the auxiliary cold plate 120, ensuring good contact in different batches of production and assembly. At the same time, its elasticity can buffer vibrations during vehicle operation, preventing overheating caused by poor contact due to vibration. Furthermore, the thermally conductive pad 140 has good insulation properties, providing an additional electrical isolation safety barrier while conducting heat efficiently, preventing accidental electrical short circuits between the heat spreader 130 (typically metal) and the auxiliary cold plate 120 (typically metal).

[0057] Please refer to Figure 5 In this embodiment, an accommodating groove is provided on the inner side of the auxiliary cold plate 120 (the side facing the cover body), and the heat-conducting pad 140 is disposed in the accommodating groove. The large surface area of ​​the heat-conducting pad 140 is appropriately smaller than the large surface area of ​​the accommodating groove because when the auxiliary cold plate 120 is pressed and assembled with the upper cover body, the heat-conducting pad 140 will be compressed and deformed. The reserved area difference provides the necessary space margin for the lateral expansion of the heat-conducting pad 140, thereby ensuring that it can be compressed evenly and fully to achieve the best contact and heat conduction effect, while avoiding excessive assembly stress due to lack of expansion space.

[0058] In this embodiment, a pipeline structure 150 is also included. The pipeline structure 150 is connected between the auxiliary cold plate 120 and the main liquid cooling plate of the battery pack housing, and is used to connect the fluid channel 121 of the auxiliary cold plate 120 with the coolant circuit of the main liquid cooling plate of the battery pack housing.

[0059] In this embodiment, the pipeline structure 150 may include two pipeline bodies, one for the inflow and one for the outflow of coolant. Connecting joints may be connected to both ends of the pipeline bodies, enabling communication with the coolant inside the auxiliary cold plate 120 and with the coolant in the main liquid-cooled plate of the battery pack housing, respectively.

[0060] Through the above embodiments, the design of the piping structure 150 integrates the local heat dissipation system of the junction box 10 with the main cooling system of the battery pack, achieving unified and coordinated thermal management of the entire battery pack (including cells and external electrical components), and simplifying the system architecture. The existing powerful heat dissipation capacity of the main liquid cooling plate of the battery pack (such as large-area heat dissipation fins and fans) can be utilized to dissipate heat from the junction box 10. The coolant circulation flow is large, the heat dissipation efficiency is high, and the temperature field of the entire system is more uniform. There is no need to equip the junction box 10 with a separate independent cooling system (such as a water pump or radiator), making full use of existing resources, significantly reducing costs and system complexity, while also reducing potential failure points and facilitating maintenance.

[0061] Based on the above embodiments, this application also provides a battery pack, including a housing and standard battery cells housed in the housing. A junction box 10 is provided on the front end plate of the housing, and the junction box 10 includes the top cover structure of the junction box 10 in any of the above embodiments. By applying this advanced top cover heat dissipation structure, the battery pack can achieve faster charging rates and continuous discharge with larger currents, thereby improving the overall vehicle operating efficiency. It effectively prevents fault risks caused by overheating inside the junction box 10 (such as accelerated fuse aging and decreased insulation performance), reduces the potential risk of thermal runaway propagation, and extends the battery pack's lifespan. It ensures that while achieving efficient heat dissipation, the battery pack maintains its high IP68 / IP69K protection standard, adapting to various harsh environments.

[0062] In this embodiment, the junction box 10 is a three-in-one structure that integrates the positive connector, the negative connector, and the manual maintenance device (MSD).

[0063] Through the above embodiments, the heat points of multiple high-current paths are concentrated in a structure with efficient heat dissipation, realizing unified management of heat in the high-voltage connection area and achieving better heat dissipation effect. Based on the above embodiments, this application also provides a battery system comprising multiple battery packs, wherein at least one battery pack is a battery pack as described in any of the above embodiments.

[0064] Since the structure of the junction box cover and the battery pack, as well as their beneficial effects, have been described in detail in the previous embodiments, they will not be repeated here.

[0065] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A top cover structure for a junction box, characterized in that, include: The upper cover body is used to close and seal with the junction box base; The upper cover body has a mounting position on the side facing the junction box base, the mounting position being used to accommodate a heating element; An inner heat-conducting layer is provided between the mounting position and the heating element, and the inner heat-conducting layer can cover at least part of the surface of the heating element; An auxiliary cooling plate is provided on the side of the upper cover body away from the junction box base. The auxiliary cooling plate is attached to the surface of the upper cover body and has a fluid channel inside for carrying away heat through the flow of cooling medium.

2. The upper cover structure according to claim 1, characterized in that, A hollow structure is provided on the upper cover body at the position corresponding to the mounting position, and a heat dissipation plate is provided in the hollow structure. The temperature distribution plate and the upper cover body are sealed together. The temperature distribution plate is located between the inner heat-conducting layer and the auxiliary cold plate. The inner side of the temperature distribution plate is in contact with the inner heat-conducting layer, and the outer side of the temperature distribution plate is in contact with the auxiliary cold plate.

3. The upper cover structure according to claim 2, characterized in that, A stepped structure is provided around the hollow structure, and the heat dissipation plate is placed on the stepped structure.

4. The upper cover structure according to claim 2, characterized in that, A thermally conductive pad is provided between the heat exchange plate and the auxiliary cold plate.

5. The cover structure according to any one of claims 1-4, characterized in that, It also includes a piping structure that connects the auxiliary cold plate and the main liquid cooling plate of the battery pack housing, for connecting the fluid channel of the auxiliary cold plate with the coolant circuit of the main liquid cooling plate of the battery pack housing.

6. The upper cover structure according to claim 1, characterized in that, The inner thermally conductive layer is a thermally conductive adhesive.

7. The upper cover structure according to claim 1, characterized in that, The heating element is a fuse or a copper busbar.

8. A battery pack, characterized in that, The device includes a housing and a standard battery cell housed within the housing. A junction box is provided on the front end plate of the housing, and the junction box includes a cover structure as described in any one of claims 1 to 7.

9. The battery pack according to claim 8, characterized in that, The junction box is a three-in-one structure that integrates the positive connector, the negative connector, and the manual maintenance device (MSD).

10. A battery system, characterized in that, It comprises multiple battery packs, at least one of which is the battery pack according to claim 8 or 9.

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