A liquid cooling system for a battery circuit unit

Abstract

The utility model provides a kind of liquid cooling system of battery circuit unit, including at least two heat exchangers;The heat exchanger is respectively fixed on the electrically conductive row inside battery circuit unit;The heat exchanger includes heat exchanger body, and with the import pipeline and export pipeline being communicated with heat exchanger body inside;Shell is provided with import header and export header;The import header one end is respectively communicated with the import pipeline of each heat exchanger;The export header one end is respectively communicated with the export pipeline of each heat exchanger;The other end of the import header and export header is respectively communicated with the export pipeline of battery heat exchange unit in battery cooling liquid circulating system;Battery cooling liquid is circulated in the heat exchanger.The utility model does not need to construct independent cooling circuit, can effectively reduce battery circuit unit temperature, improve loop current-carrying capacity and system stability.

Description

Technical Field

[0001] This utility model belongs to the field of battery pack technology, specifically relating to a liquid cooling system for a battery circuit breaker unit. Background Technology

[0002] With the rapid development of new energy vehicle technology, in order to alleviate consumers' anxiety about driving range, vehicle manufacturers have been increasing the rated voltage platform of power battery systems from the traditional 400V to 800V and higher levels to achieve higher peak charging and discharging power and faster recharge speed. However, the increase in voltage platform is accompanied by a sharp increase in the heat generation of the battery cells under high-rate charging and discharging conditions, and the battery pack cooling system must bear a greater heat dissipation load.

[0003] Currently, most mainstream battery thermal management solutions focus on cell-level liquid cooling: liquid cooling plates are placed between each cell assembly, and the coolant is circulated through a refrigeration unit or PTC heater-circulating water pump to actively control the temperature of the cells. While this solution can effectively suppress excessive cell temperature, the battery disconnect unit (BDU) is often overlooked in actual vehicle applications.

[0004] As a key module in the battery pack used for high-current devices such as main negative relays, main positive relays, pre-charge relays, and Hall sensors, the Battery Duct Connector (BDU) achieves electrical connection and circuit continuity with the battery cells through conductive busbars. When the battery system is charging and discharging at high power, the conductive busbars and relay contacts inside the BDU generate heat comparable to that of the battery cells.

[0005] 1) Conductor bus resistance effect: For every 10°C increase in surface temperature of the conductor bus, its resistance increases by about 3.5%, resulting in a decrease in the current carrying capacity of the circuit;

[0006] 2) Risk of localized overheating: Uneven heating of relay contacts and conductors can easily lead to thermal stress concentration, accelerating component aging, and even causing contact erosion or "cold solder joints".

[0007] 3) System derating and reliability: In order to avoid BDU overheating, the battery management system (BMS) often adopts current limiting and derating strategies, which in turn affects the vehicle's power output and driving range; at the same time, abnormal BDU temperature will also reduce the long-term stability of the vehicle's electrical system.

[0008] To address the heat dissipation requirements of BDUs, existing technologies mainly employ the following approaches:

[0009] 1) Air cooling or forced fan cooling

[0010] Heat sinks and fans are installed on the BDU housing to improve the heat transfer coefficient through convection. However, the limited space within the vehicle restricts the airflow arrangement, and the fan's noise, reliability, and dust and water resistance design also bring additional costs and maintenance difficulties.

[0011] 2) Independent liquid cooling circuit

[0012] A separate low-flow liquid cooling circuit was designed for the BDU, using miniature cold plates or shell-and-tube heat exchangers to cool the busbars. However, this approach increases the number of piping branches and cooling elements in the liquid cooling system, raising system complexity, cost, and the risk of piping leaks. It also makes it difficult to optimize in conjunction with the overall thermal management of the battery pack.

[0013] 3) Improved thermal conductivity structure

[0014] By adding a thermally conductive pad or adhesive between the conductive busbar and the housing, heat is conducted to the outer casing, and then dissipation relies on the vehicle body structure. This type of passive cooling method is limited by the heat conduction path, resulting in limited cooling efficiency and making it difficult to meet the cooling requirements under high-rate operating conditions.

[0015] In summary, how to effectively reduce the temperature of key components such as the internal busbars and relays of the BDU, improve the current carrying capacity of the circuit, and ensure the stability of the battery system without significantly increasing the complexity of the vehicle's liquid cooling system has become a technical challenge that needs to be addressed by existing technologies. Utility Model Content

[0016] The purpose of this invention is to address the shortcomings of the aforementioned background technology and provide a liquid cooling system for a battery circuit breaker unit (BDU) that can effectively reduce the BDU temperature, improve the circuit current carrying capacity, and enhance system stability without the need for an independent cooling circuit.

[0017] The technical solution adopted by this utility model is: a liquid cooling system for a battery circuit breaker unit, wherein the battery circuit breaker unit includes a housing and circuit components disposed within the housing; the circuit components are fixedly installed inside the housing via conductive busbars;

[0018] It includes at least two heat exchangers; the heat exchangers are respectively fixed on the conductive busbar inside the battery circuit breaker unit;

[0019] The heat exchanger includes a heat exchanger body, and an inlet pipe and an outlet pipe that are connected to the interior of the heat exchanger body.

[0020] The casing is equipped with an inlet manifold and an outlet manifold;

[0021] One end of the inlet manifold is connected to the inlet pipe of each heat exchanger; one end of the outlet manifold is connected to the outlet pipe of each heat exchanger.

[0022] The other ends of the inlet manifold and the outlet manifold are respectively connected to the outlet pipe of the battery heat exchange unit in the battery coolant circulation system; and in the direction of battery coolant flow, the connection point between the inlet manifold and the outlet pipe of the battery heat exchange unit is in front, and the connection point between the outlet manifold and the outlet pipe of the battery heat exchange unit is behind.

[0023] Battery coolant circulates within the heat exchanger.

[0024] In the above technical solution, the battery heat exchange unit is a liquid cooling plate.

[0025] In the above technical solution, the outlet main pipe is composed of two parallel branch pipes: a first outlet main pipe and a second outlet main pipe.

[0026] The first and second outlet manifolds are connected to the outlet pipes of each heat exchanger via a single port at their common end.

[0027] The other end of the first outlet manifold is connected to the outlet pipe of the battery heat exchange unit;

[0028] The other end of the second outlet manifold is connected to the inlet pipe of the battery heat exchange unit.

[0029] In the above technical solution, a first solenoid valve is installed on the second outlet main pipe; a second solenoid valve is installed on the inlet main pipe; and a third solenoid valve is installed on the first outlet main pipe.

[0030] It also includes a control unit and a temperature sensor. The temperature sensor is in contact with the battery, and its signal output is electrically connected to the signal input of the control unit. The control unit's signal output is electrically connected to the signal inputs of the first, second, and third solenoid valves. The control unit is constructed or configured to operate based on the battery temperature.

[0031] When the temperature is higher than the first threshold, that is, when the battery liquid cooling system is in cooling mode, the first solenoid valve is closed and the second and third solenoid valves are opened.

[0032] When the temperature is below the second threshold, i.e. when the battery liquid cooling system is in heating mode, the second solenoid valve and the first solenoid valve are opened and the third solenoid valve is closed.

[0033] When the temperature is between the first threshold and the second threshold, i.e. when the battery liquid cooling system is not working, the first solenoid valve, the second solenoid valve, and the third solenoid valve are closed simultaneously.

[0034] The above technical solution also includes a temperature sensor, which is in contact with the battery and electrically connected to the control unit.

[0035] In the above technical solution, the common end of the first outlet main pipe and the second outlet main pipe, as well as the end of the inlet main pipe that connects to each heat exchanger, all extend into the shell and the ends are closed structures; the pipe walls of the two main pipes are uniformly provided with a number of distribution holes along the length direction, and each distribution hole is located inside the shell and is connected to the inlet pipe of the corresponding heat exchanger one by one.

[0036] In the above technical solution, the heat exchanger is disposed on the conductive busbar on one side of the heating device in the battery circuit breaker unit or on the body of the heating device.

[0037] In the above technical solution, heat exchangers are installed on the conductive busbars surrounding the Hall sensor, main negative relay, precharge relay, precharge resistor, main fuse, and main positive relay; a heat exchanger is installed on the main positive relay.

[0038] In the above technical solution, the heat exchanger body is fixed to the surface of the conductive busbar and the heating element by thermally conductive structural adhesive.

[0039] In the above technical solution, the battery coolant circulation system includes a heater, a cooler, a circulating water pump, and a battery heat exchange unit; the heater, cooler, circulating water pump, and battery heat exchange unit are connected by pipelines; battery coolant flows through the pipelines; the battery heat exchange unit contacts the battery for heat exchange; the signal output terminal of the control unit is electrically connected to the signal input terminals of the heater, cooler, and circulating water pump. The control unit is constructed or configured to operate based on the battery temperature:

[0040] When the temperature exceeds the first threshold, the heater is turned off and the cooler and circulating water pump are turned on.

[0041] When the temperature is below the second threshold, the refrigerator is shut down and the heater and circulating water pump are turned on.

[0042] When the temperature is between the first threshold and the second threshold, the heater, cooler, and circulating water pump are simultaneously shut down.

[0043] The beneficial effects of this invention are as follows: In the same liquid cooling circuit, a branch is branched off from the battery liquid cooling plate outlet, which cools the key components inside the BDU (Block Utility Unit) via at least two heat exchangers that are in direct contact with the busbar, before returning to the main circuit. This invention utilizes the existing cooling cycle at the battery end, eliminating the need for additional independent circuits or pumps, thus minimizing system complexity and cost increases. The heat exchangers are directly fixed to the busbar, shortening the heat conduction path and significantly reducing the temperature of the busbar and relays inside the BDU. The reduced temperature decreases the resistance of the busbar, increasing the maximum current carrying capacity. Simultaneously, it avoids device aging or contact erosion caused by overheating, improving system reliability.

[0044] Furthermore, this utility model limits the battery-side heat exchange unit to a liquid cooling plate, sharing the same structural form and pipeline interface with the heat exchanger of the BDU, thereby achieving a high degree of consistency between the BDU heat exchanger and the battery liquid cooling plate in manufacturing and installation, simplifying component standardization and inventory management; avoiding the leakage risk caused by heterogeneous pipeline interfaces, and enhancing the integrated reliability of the overall pipeline system.

[0045] Furthermore, this invention divides the main outlet pipe into two branch pipes—one connected to the outlet pipe of the battery liquid cooling plate and the other connected to the inlet pipe of the battery liquid cooling plate—and connects them respectively to the outlet pipes of each parallel heat exchanger. In cooling mode, the coolant flowing through the BDU can return to the main circulation through the low-temperature branch pipe connected to the battery liquid cooling plate outlet, achieving efficient heat dissipation. In heating mode, the higher-temperature coolant flowing through the BDU can return to the battery through the high-temperature branch pipe connected to the battery liquid cooling plate inlet, achieving secondary preheating of the battery. Both cooling and heating flow directions can be met with just two fixed branch pipes, eliminating the need for additional independent circuits or pumps, thus maintaining the flexibility of thermal management while reducing system complexity and cost.

[0046] Furthermore, this invention arranges three sets of solenoid valves on the inlet manifold, the first outlet manifold, and the second outlet manifold, and switches them by the control unit based on the battery temperature signal: regardless of whether the system is in cooling or heating mode, the coolant flowing through the battery will immediately flow through the BDU parallel heat exchanger to effectively cool the internal conductive busbars and relays of the BDU; in heating mode, the coolant flowing through the BDU remains at a high temperature and is returned to the battery heat exchange unit after switching through the first outlet manifold for battery preheating;

[0047] In cooling mode, the coolant flowing through the BDU returns to the cooling circulation system through the second outlet manifold, eliminating the need for a separate circuit and thus achieving temperature control for both the BDU and the battery.

[0048] Furthermore, this invention incorporates a temperature sensor in close contact with the battery at the BDU or battery pack, feeding the temperature signal back to the control unit. This enables real-time monitoring of the cell and BDU temperatures, ensuring accurate and reliable operation of valves / pumps / heating / cooling devices. Combined with threshold logic closed-loop control, it significantly improves temperature control accuracy and response speed, preventing overheating or undercooling.

[0049] Furthermore, the distribution holes of this invention are arranged at equal intervals along the pipe wall and connected to each heat exchanger in a one-to-one manner. This ensures that the coolant flow rate entering each parallel heat exchanger is equal, avoiding local overcooling or overheating caused by differences in flow path resistance, and improving overall heat dissipation consistency. After sealing the pipe ends, all coolant can only enter the heat exchanger through the distribution holes, eliminating the risk of pipe end leakage and ensuring long-term reliable operation of the system under high pressure (e.g., ≤1.2MPa) and vibration environments. All main pipe ends extend into the housing, so that the connection between the heat exchanger and the main pipe is hidden inside the housing. This not only saves external space but also reduces the interference of exposed pipes on the overall vehicle layout, improving system integration and maintenance convenience. Through the one-to-one distribution method, each loop can obtain stable and predictable flow rate and temperature drop, keeping the internal components of the BDU within a safe temperature range and reducing electrical risks such as increased conductor resistance and relay contact failure caused by overheating. Whether in cooling or heating mode, the uniform distribution of the flow orifices can adapt to different flow rates and temperature differences, ensuring that the BDU can obtain sufficient and balanced cooling in any temperature control mode, further improving the response efficiency and energy efficiency of the vehicle's thermal management system.

[0050] Furthermore, the heat exchanger body of this invention adopts a microchannel structure, and its inlet / outlet pipes can be arranged at any edge of the body. The microchannel structure is characterized by small channel diameter and high channel density, which significantly increases the heat exchange area per unit volume and the convective heat transfer coefficient; it can achieve higher heat dissipation capacity within a limited BDU space, while maintaining a smaller heat exchanger size, providing greater flexibility for the overall vehicle layout.

[0051] Furthermore, this invention places the heat exchanger directly on the busbar or device body where the internal heat-generating components (such as relays and Hall sensors) of the BDU are located. Utilizing the shortest heat conduction path, heat from localized high-heat-flux areas is rapidly transferred to the heat exchanger, suppressing hotspot formation; achieving targeted, point-to-point cooling, avoiding the thermal hysteresis effect of passive heat dissipation methods, and improving heat dissipation response efficiency.

[0052] Furthermore, this invention arranges heat exchangers around typical high-heat areas inside the BDU, such as the Hall effect sensor, main negative / main positive relay, pre-charge relay, and pre-charge resistor. This provides concentrated and balanced cooling for multiple key heat-generating points, further suppressing local temperature peaks. The distributed microchannel heat exchanger combination ensures the uniformity of the temperature field throughout the BDU, improving the reliability of component coordination.

[0053] Furthermore, this invention employs thermally conductive structural adhesive to fix the heat exchanger body to the surface of the conductive busbar and the heat source device, forming a highly efficient thermal contact interface. The thermally conductive adhesive fills the tiny gaps between the conductive busbar and the heat exchanger, eliminating contact thermal resistance and ensuring rapid heat transfer; it also reduces mechanical fasteners, simplifies the installation process, and improves structural compactness and vibration resistance.

[0054] Furthermore, this utility model's battery coolant circulation system integrates a heater, a cooler, and a circulating water pump. The control unit automatically switches between these components based on battery temperature. Under high-temperature conditions (temperature above a first threshold), the cooler and circulating water pump are quickly activated to force cooling of the battery. Under low-temperature conditions (temperature below a second threshold), the heater and circulating water pump are quickly activated to efficiently preheat the battery. Under medium-temperature conditions (between the thresholds), the heater, cooler, and circulating water pump are shut off, achieving zero-power standby. By activating the corresponding devices as needed, energy waste from continuous operation is avoided. The coordinated operation of the heating / cooling devices and the pump allows the system to complete temperature adjustment within seconds, improving the battery's low-temperature start-up performance and high-temperature safety margin. No additional piping branches or independent circulation loops are required; a single heating / cooling-pump control combination can manage temperature under all operating conditions. The centralized control unit reduces external wiring and calibration complexity, improving the reliability and maintenance convenience of the vehicle's thermal management system. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the pipeline architecture of this utility model;

[0056] Figure 2 This is an external schematic diagram of the present invention;

[0057] Figure 3 This is a schematic diagram of the internal structure of this utility model;

[0058] Figure 4 This is a schematic diagram of the heat exchanger of this utility model;

[0059] Figure 5 This is an installation diagram of the heat exchanger of this utility model;

[0060] Figure 6 This is a schematic diagram of the end of the inlet manifold of this utility model;

[0061] Figure 7 This is a schematic diagram of the end of the outlet manifold of this utility model.

[0062] Among them, 1-upper shell, 2-lower shell, 3-inlet manifold, 4-outlet manifold, 41-first inlet manifold, 42-second inlet manifold, 5-conductive busbar, 6-heat exchanger, 61-heat exchanger body, 62-heat exchanger inlet pipe, 63-heat exchanger outlet pipe, 7-Hall sensor, 8-main negative relay, 9-pre-charge relay, 10-main positive relay, 11-pre-charge resistor, 12-main fuse, 13-thermal conductive adhesive, 14-cooled component (conductive busbar or heating element body), 15-distribution hole. Detailed Implementation

[0063] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but these descriptions do not constitute a limitation on the present invention.

[0064] like Figure 1 As shown, this utility model provides a liquid cooling system for a battery circuit breaker unit, the battery circuit breaker unit including a housing and circuit components disposed within the housing; the circuit components are fixedly installed inside the housing via conductive busbars 5;

[0065] It includes at least two heat exchangers 6; the heat exchangers 6 are respectively fixed on the conductive busbar 5 inside the battery circuit breaker unit;

[0066] like Figure 2 As shown, the heat exchanger 6 includes a heat exchanger body 61, and an inlet pipe and an outlet pipe that are connected to the interior of the heat exchanger body 61.

[0067] The casing is equipped with an inlet manifold 3 and an outlet manifold 4;

[0068] One end of the inlet manifold 3 is connected to the inlet pipe of each heat exchanger 6; one end of the outlet manifold 4 is connected to the outlet pipe of each heat exchanger 6.

[0069] The other ends of the inlet manifold 3 and the outlet manifold 4 are respectively connected to the outlet pipe of the battery heat exchange unit in the battery coolant circulation system; and in the direction of battery coolant flow, the connection point between the inlet manifold 3 and the outlet pipe of the battery heat exchange unit is in front, and the connection point between the outlet manifold 4 and the outlet pipe of the battery heat exchange unit is behind.

[0070] Battery coolant circulates within the heat exchanger 6.

[0071] Specifically, the battery heat exchange unit is a liquid cooling plate, and the inlet and outlet of the liquid cooling plate are connected to the battery coolant circulation system pipeline.

[0072] The housing consists of an upper housing 1 and a matching lower housing, which are secured together by interlocking snaps and concealed screws, enabling rapid assembly and reliable sealing. The upper housing 1 is injection molded from high-temperature resistant engineering plastic, with a flat top to support subsequent functional modules and cover plates; the lower housing has a reinforcing rib structure at the bottom to enhance overall bending rigidity and provide stable support for the internal conductive busbar 5 and heat exchanger 6.

[0073] The inlet manifold 3 and outlet manifold 4 are pre-positioned on the mounting platform on one side of the lower housing using plastic slots, and O-ring grooves are reserved inside the slots to ensure the sealing of the quick-connect pipe interface.

[0074] In this embodiment, the liquid cooling plate is made of a high thermal conductivity aluminum alloy sheet. Internally, several parallel rectangular flow channels are formed through chemical etching or precision milling. The channel width is approximately 1.0–1.5 mm, and the spacing is 0.3 mm, providing a large heat exchange interface within a limited volume. Each end of the flow channel has a manifold to evenly distribute the inlet coolant to each microchannel and collect the heat-absorbing return water before sending it to the outlet. To prevent leakage, both the inlet and outlet of the plate are sealed with fluororubber O-rings and reliably connected to the main circuit pipeline via flanges or threaded interfaces.

[0075] The outer surface of the liquid cooling plate can be anodized, which improves corrosion resistance and achieves a balance between electrical insulation and heat dissipation efficiency. The back of the plate can be fitted with elastic support pads or silicone pads to ensure a tight fit with the cell module or module side panel during installation, minimizing thermal resistance. During installation, the liquid cooling plate is pressed against the battery module side frame using bolts or clips, creating a stable thermal contact between the plate and the cell casing. This liquid cooling plate can be placed on the side of a single row of cells within the battery pack, or installed in groups between multiple rows of cells in the module, flexibly adapting to different battery pack layouts. Through this structural design, the liquid cooling plate can efficiently conduct the heat generated by the cells to the coolant, providing a stable and uniform cold source for the subsequent secondary cooling process flowing through the internal heat exchanger 6 of the BDU.

[0076] Specifically, such as Figure 1 As shown, the outlet main pipe 4 consists of two parallel branch pipes, the first outlet main pipe 41 and the second outlet main pipe 42.

[0077] The first outlet manifold 41 and the second outlet manifold 42 are connected to the outlet pipes of each heat exchanger 6 through a single port at their common end.

[0078] The other end of the first outlet manifold 41 is connected to the outlet pipe of the battery heat exchange unit;

[0079] The other end of the second outlet manifold 42 is connected to the inlet pipe of the battery heat exchange unit.

[0080] The common end of the first outlet main pipe 41 and the second outlet main pipe 42, as well as the end of the inlet main pipe 3 that connects to each heat exchanger 6, all extend into the shell and the ends are closed structures; the pipe walls of the two main pipes are evenly provided with a number of distribution holes 15 along the length direction, and each distribution hole 15 is located inside the shell and is connected to the inlet pipe of the corresponding heat exchanger 6 one by one.

[0081] Preferably, in this embodiment, the outlet main pipe 4 adopts an integrated dual-branch pipe structure, the main body of which is made of corrosion-resistant stainless steel or aluminum alloy, and is arranged horizontally on the rear side of the battery circuit breaker unit housing. This dual-branch pipe consists of a horizontal manifold and two vertical branch pipes. The manifold has a continuous rectangular flow channel inside, and its two ends can be tightly connected to the outlet pipe of the liquid cooling plate in the battery coolant circulation system or the interface plate of the BDU housing using welded flanges. The first outlet branch pipe branches out from the upper side of the manifold, and its diameter is typically 8mm. It is connected to the outlet pipe of the battery heat exchange unit via a quick-connect snap-fit ​​connector or a threaded adapter; a fluororubber O-ring is provided at the pipe end to ensure no leakage under the highest system operating pressure (≤1.2MPa). The second outlet branch pipe branches out from the lower side of the manifold, also with a diameter of 8mm, and is connected to the inlet pipe of the battery heat exchange unit via the same type of connector.

[0082] The inlet manifold 3 is a distribution manifold formed by integral extrusion or welding, with a closed end. Several distribution holes 15 are evenly distributed along its length, each corresponding spatially to the inlet pipe of the heat exchanger 6. All distribution holes 15 are located inside the shell. External threads or pressed-formed flared ends are machined into the distribution holes 15. The threaded end is inserted into a high-pressure resistant coolant hose (i.e., the inlet pipe of the heat exchanger 6) and tightened with a sealing nut, or directly connected to a one-time quick-connect fitting with a double snap ring structure, achieving zero-leakage sealing using internal fluororubber O-rings. The hoses branch off from the inlet manifold 3 and extend downwards to the inlet interface of their respective heat exchangers 6. The length and layout of all branch hoses (i.e., the inlet pipes of the heat exchangers 6) have been optimized to minimize bending radii, reduce pressure drop, and balance flow rates.

[0083] The common end of the first outlet main pipe 41 and the second outlet main pipe 42 is similar in structure to the inlet main pipe 3, with a closed end. Several distribution holes 15 are evenly distributed along the length of the pipe wall, each spatially corresponding to the inlet interface of the corresponding heat exchanger 6. All distribution holes 15 are located inside the shell. The hot and coolant flowing through each heat exchanger 6 can smoothly converge into the outlet main pipe 4, and the merged fluid returns to the circulation system via the main channel of the outlet main pipe 4. The inner diameter of the outlet branch pipes and the number of distribution holes 15 are precisely matched according to the flow requirements of the heat exchanger 6. If necessary, flow balancing holes can be lined inside the main pipe to further balance the return pressure of each branch.

[0084] Specifically, a first solenoid valve is installed on the second outlet manifold 42; a second solenoid valve is installed on the inlet manifold 3; and a third solenoid valve is installed on the first outlet manifold 41. All three solenoid valves are one-way valves, allowing only the coolant in their respective pipes to flow according to the specified flow rate. Figure 1The arrows indicate the direction of flow. Specifically, the second solenoid valve allows coolant to flow into the battery disconnect unit's cooling system; the first and third solenoid valves allow coolant to flow out of the battery disconnect unit's cooling system.

[0085] It also includes a control unit and a temperature sensor. The temperature sensor is in contact with the battery, and its signal output is electrically connected to the signal input of the control unit. The control unit's signal output is electrically connected to the signal inputs of the first, second, and third solenoid valves. The control unit is configured or set to operate based on the battery temperature.

[0086] When the temperature is higher than the first threshold, that is, when the battery liquid cooling system is in cooling mode, the first solenoid valve is closed and the second and third solenoid valves are opened.

[0087] When the temperature is below the second threshold, i.e. when the battery liquid cooling system is in heating mode, the second solenoid valve and the first solenoid valve are opened and the third solenoid valve is closed.

[0088] When the temperature is between the first threshold and the second threshold, i.e. when the battery liquid cooling system is not working, the first solenoid valve, the second solenoid valve, and the third solenoid valve are closed simultaneously.

[0089] In this embodiment, in order to take into account the temperature control requirements of the battery pack and the circuit breaker unit (BDU) under both heating and cooling conditions, a first solenoid valve, a second solenoid valve, and a third solenoid valve are respectively installed in the second outlet manifold 42, the inlet manifold 3, and the first outlet manifold 41 of the circuit breaker unit. The control unit switches the three sets of solenoid valves in coordination according to the battery temperature signal.

[0090] When the battery is in cooling mode and the temperature is higher than the first threshold, the control unit closes the first solenoid valve on the second outlet manifold 42 and opens the second solenoid valve on the inlet manifold 3 and the third solenoid valve on the first outlet manifold 41. At this time, the circulating water pump after the chiller or PTC first introduces the low-temperature coolant into the liquid cooling plate to cool the battery. The higher-temperature coolant at the outlet of the liquid cooling plate flows to the next stage, and is diverted into the inlet manifold 3 through the opened second solenoid valve. Then it passes through the heat exchanger 6 connected in parallel on the internal conductive busbar 5 of the BDU, quickly removes the heat of the internal components of the BDU, and flows back to the liquid cooling plate manifold through the third solenoid valve into the first outlet manifold 41, thereby cooling the BDU.

[0091] When the battery is in heating mode and its temperature is below the second threshold, the control unit opens the second and first solenoid valves and closes the third solenoid valve. At this time, the circulating water pump heated by the PTC first sends the high-temperature hot and cold liquid into the liquid cooling plate to preheat the battery. The coolant at the outlet temperature of the liquid cooling plate continues to flow through the opened second solenoid valve into the BDU heat exchanger 6, prioritizing cooling and protection of the internal conductive busbar 5 and relays of the BDU. Then, it flows through the opened first solenoid valve into the second outlet manifold 42 and finally returns to the inlet pipe of the liquid cooling plate. This process cools the BDU while retaining sufficient residual heat to return to the battery for heating. Since the BDU temperature is significantly higher than the battery temperature, even the liquid temperature used to heat the battery is still lower than the temperature of the BDU itself, and therefore can be used to cool the BDU.

[0092] When the battery temperature is within the intermediate temperature range between the preset first and second thresholds, the control unit simultaneously closes the first, second, and third solenoid valves. This prevents the circulating coolant flowing through the battery liquid cooling plate from being diverted to the BDU, and the BDU heat exchanger 6 stops liquid cooling, relying solely on passive heat dissipation to maintain a stable temperature. Through this solenoid valve switching strategy, coolant can flow through the BDU under different operating conditions to achieve temperature control protection for the circuit breaker unit. Simultaneously, in heating mode, the waste heat absorbed by the BDU can be recycled back to the battery, achieving cascaded heat utilization and maximizing energy efficiency.

[0093] The control unit can be any device with data receiving, storage, and transmission functions. The technical solution claimed in this utility model only relates to the device for acquiring and calculating the necessary data for temperature signals. In the technical solution claimed in this utility model, the controller is only used to receive and store pulse signals acquired by the temperature sensor; the calculation and analysis of the pulse signals by the controller are not part of the technical solution claimed in this utility model. This utility model is only a data acquisition device, not a data processing device; that is, how to calculate the powertrain angular domain torsional vibration signal is not the technical problem this utility model aims to solve. The technical problem solved by this utility model is how to simply, efficiently, and stably acquire and summarize the relevant data required for calculating the powertrain angular domain torsional vibration signal without affecting engine operation, facilitating subsequent calculation and analysis.

[0094] Specifically, the heat exchanger body 61 adopts a microchannel heat exchanger 6, and its inlet pipe 62 and outlet pipe 63 are respectively arranged on adjacent sides, opposite sides or the same side of the heat exchanger body 61.

[0095] Preferably, in this embodiment, the heat exchanger body 61 is a square cavity structure, which is made of aluminum alloy sheet through extrusion forming and brazing splicing processes. Multiple microchannels with a cross-section of 1mm × 1mm are formed inside the cavity. These microchannels are arranged parallel to each other along the thickness direction of the sheet, with a wall thickness of approximately 0.3mm between the channels to ensure maximum heat exchange area and minimum thermal resistance within a limited volume. The cavity is anodized to enhance corrosion resistance and provide necessary electrical insulation.

[0096] The heat exchanger body 61 is equipped with inlet pipe 62 and outlet pipe 63 connection sections. Each connection section is a cylindrical tube neck integrally brazed with the microchannel cavity, with standard threads machined on its outer surface and an O-ring groove at the root of the thread. External stainless steel or aluminum alloy pipes are connected to the tube neck via threads, with the O-ring located inside the mating surface. Tightening the nut achieves zero-leakage sealing under high pressure (≤1.2MPa) and high vibration conditions. The brazed seam between the tube neck of inlet pipe 62 and outlet pipe 63 and the cavity of the heat exchanger body 61 is approximately 0.5mm wide. The filler metal is filled through capillary action, ensuring pressure resistance and corrosion resistance. Both inlet pipe 62 and outlet pipe 63 are flexible hoses.

[0097] To accommodate different spatial layouts within the BDU, the inlet and outlet necks can be arranged on adjacent sides, opposite sides, or the same side of the microchannel cavity: when the space is narrow and the pipelines need to be arranged in parallel, the inlet and outlet necks can be placed on the same side to reduce the overall length; when it is necessary to achieve flow splitting and return on both sides of the cavity, the necks can be arranged on opposite sides; if it is necessary to fit the side wall of the shell or a corner, the pipeline can be led out in the direction of the corner by using the adjacent side arrangement method.

[0098] This structure not only ensures the high-efficiency heat transfer performance of the microchannel heat exchanger, but also enables reliable, detachable, tool-free, and rapid assembly with the external inlet manifold 3 and outlet manifold 4 through the use of standard tube neck + O-ring + threaded connection.

[0099] like Figure 3 Specifically, the heat exchanger 6 is disposed on the conductive busbar 5 on one side of the heating device within the battery circuit breaker unit or on the body of the heating device. The heat exchanger 6 is disposed on the conductive busbar 5 surrounding the Hall effect sensor, main negative relay 8, pre-charge relay 9, pre-charge resistor 11, main fuse 12, and main positive relay 10; the heat exchanger 6 is disposed on the main positive relay 10.

[0100] like Figure 5 As shown, the heat exchanger body 61 is fixed to the conductive busbar 5 and the surface of the heating device by thermally conductive structural adhesive 13. Figure 5 The middle arrow indicates the direction of heat conduction.

[0101] Preferably, in this embodiment, all heat exchanger bodies 61 are square cavities, each heat exchanger 6 having a side length of approximately 20–30 mm and a thickness of 4–6 mm. They are pre-brazed and anodized in the form of square plates. Each square cavity has a Φ6 mm cylindrical neck at the center of its corresponding side, serving as the inlet and outlet pipe interfaces, respectively. The outer side of the neck is machined with standard threads and equipped with O-ring grooves to facilitate high-pressure sealing with the conduit via nut tightening.

[0102] Inside the BDU, multiple square heat exchangers 6 are sequentially attached along the conductive busbar 5 and the surface of the heating devices: a pair of square heat exchangers 6 are attached to the side of the conductive busbar 5 at the positions of the Hall sensor 7 and the main negative relay 8; two square heat exchangers 6 are attached to the conductive busbar 5 where the pre-charge relay 9 and the pre-charge resistor 11 are located to cover their respective heating areas; at the main positive relay 10, a square heat exchanger 6 is attached to its mating surface to ensure the shortest possible flow path distance between the neck and the branch pipe connection on the side wall of the casing. A 0.2mm thick high thermal conductivity structural adhesive is applied between all square heat exchangers 6 and the conductive busbar 5 or the surface of the device body. After the adhesive film initially sets, it is fixed with a light pressure clamp until the thermally conductive adhesive is fully cured to ensure minimal interfacial thermal resistance.

[0103] After bonding, the inlet neck of each square heat exchanger 6 is connected to the distribution branch of the inlet main pipe 3 via a flexible hose (i.e., inlet pipe) and a quick-connect fitting; the outlet neck is similarly connected to the corresponding branch of the outlet main pipe 4. The entire bonding process requires no drilling or machining; it only requires cleaning the surface, applying adhesive, bonding, initial curing, and quick-connect fitting. This allows for the efficient networking of multiple square microchannel heat exchangers 6 within a confined space, ensuring that all key components of the BDU receive uniform and stable liquid cooling protection under any operating conditions.

[0104] Specifically, the battery coolant circulation system includes a heater, a cooler, a circulating water pump, and a battery heat exchange unit; the heater, cooler, circulating water pump, and battery heat exchange unit are connected by pipelines; battery coolant flows through the pipelines; the battery heat exchange unit contacts the battery for heat exchange; the signal output terminal of the control unit is electrically connected to the signal input terminals of the heater, cooler, and circulating water pump. The control unit is constructed or configured to operate based on the battery temperature:

[0105] When the temperature exceeds the first threshold, the heater is turned off and the cooler and circulating water pump are turned on.

[0106] When the temperature is below the second threshold, the refrigerator is shut down and the heater and circulating water pump are turned on.

[0107] When the temperature is between the first threshold and the second threshold, the heater, cooler, and circulating water pump are simultaneously shut down.

[0108] Preferably, in this embodiment, the battery coolant circulation system consists of four main parts: a heater, a chiller, a circulating water pump, and a battery liquid cooling plate. The heater uses a PTC heating element, whose resistance network automatically limits the current after reaching a predetermined temperature; the chiller is a small compressor-driven chiller unit, and the refrigerant is delivered after the circulating water / ethylene glycol solution is cooled to a set temperature through an evaporator; the circulating water pump is a bidirectional adjustable speed centrifugal pump, which can quickly switch the flow rate or close the flow path according to system requirements; the battery liquid cooling plate is manufactured according to the aforementioned microchannel structure and is tightly fitted to the battery module shell.

[0109] The entire system piping uses 1.2MPa pressure-resistant hoses and aluminum alloy fittings, with flanges and O-rings or quick-connect clips at the interfaces to ensure leak-free operation under high vibration and temperature difference conditions. The control unit receives signals from temperature sensors at the battery side panel and liquid cooling plate outlet, driving the opening / closing and speed adjustment of the three-way valve, PTC, chiller, and water pump to achieve closed-loop temperature management: priority cooling under high temperature conditions, priority heating under low temperature conditions, and shutdown / standby under medium temperature conditions. This ensures continuous and efficient temperature control protection for both the battery and BDU within the same cooling circuit, regardless of whether it's cooling or heating mode.

[0110] The control unit employs an automotive-grade MCU architecture and features two Pt100 platinum resistance or semiconductor temperature sensors, respectively attached to the battery module side panel and the coolant manifold, for real-time acquisition of battery pack and coolant temperatures. The MCU's digital output directly drives the solid-state relay of the PTC heater, the solenoid valve of the chiller, and the inverter driver of the water pump. Through vehicle bus (CAN) communication, the control unit can also coordinate with the body controller to ensure that the cooling logic is consistent with the vehicle's thermal management strategy.

[0111] During operation, when the battery side panel temperature sensor detects a temperature higher than the first threshold (e.g., 45°C), the control unit shuts off the PTC heater output, sends a cooling command to the Chiller, and starts the circulating water pump to a preset speed (e.g., 2,000 rpm), allowing the coolant to be cooled in series via the liquid cooling plate and BDU heat exchanger 6. When the temperature is lower than the second threshold (e.g., 5°C), the control unit shuts off the Chiller compressor and starts the PTC heater, while maintaining the water pump operation to ensure a rapid rise in coolant temperature. When the temperature is between the two (5°C–45°C), the control unit issues a "shutdown" command, stopping the PTC, Chiller, and water pump, and putting the system into a low-power standby state.

[0112] In addition, the control unit has over-temperature protection and flow detection functions: if the flow sensor feedback is lower than the set value (e.g., <2L / min), or the pressure sensor detects abnormal pressure in the circuit, the cooler and heater will be immediately shut down, and an alarm signal will be issued; if the temperature continues to exceed the second threshold for more than two minutes, it will enter forced circulation or derating mode to improve system safety and reliability. This specific embodiment can not only dissipate heat quickly under high-temperature conditions, but also preheat efficiently in low-temperature environments, meeting the temperature management requirements of the battery and BDU across the entire temperature range.

[0113] In this invention, the control unit serves only as a hardware device with signal receiving, storage, and output functions. Its main function is to receive pulse signals from the temperature sensor and directly output on / off control signals for the electronic valve (and circulating water pump, heater / cooler) according to preset threshold logic. The control unit contains only minimal hardware / firmware logic for comparing the pulse temperature signal acquired by the sensor with the preset threshold and generating digital output signals to open or close the electronic valve, circulating water pump, and heater / cooler based on the comparison result. This logic is limited to hardware or simple firmware decision functions for "above / below the threshold" and does not involve more advanced temperature algorithm calculations, curve fitting, or machine learning analysis. This invention only protects the structure and function of the hardware device—that is, the temperature data acquisition path and the control signal output path—to provide stable and real-time hardware interface support for subsequent software algorithms and decision logic, without involving the specific signal processing or control algorithms themselves.

[0114] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A liquid cooling system for a battery circuit breaker unit, the battery circuit breaker unit comprising a housing and circuit components disposed within the housing; the circuit components being fixedly mounted inside the housing via conductive busbars; characterized in that: It includes at least two heat exchangers; the heat exchangers are respectively fixed on the conductive busbar inside the battery circuit breaker unit; The heat exchanger includes a heat exchanger body, and an inlet pipe and an outlet pipe that are connected to the interior of the heat exchanger body. The casing is equipped with an inlet manifold and an outlet manifold; One end of the inlet manifold is connected to the inlet pipe of each heat exchanger; one end of the outlet manifold is connected to the outlet pipe of each heat exchanger. The other ends of the inlet manifold and the outlet manifold are respectively connected to the outlet pipe of the battery heat exchange unit in the battery coolant circulation system; and in the direction of battery coolant flow, the connection point between the inlet manifold and the outlet pipe of the battery heat exchange unit is in front, and the connection point between the outlet manifold and the outlet pipe of the battery heat exchange unit is behind. Battery coolant circulates within the heat exchanger.

2. The liquid cooling system of the battery circuit breaker unit according to claim 1, characterized in that: The battery heat exchange unit is a liquid cooling plate.

3. The liquid cooling system of the battery circuit breaker unit according to claim 1, characterized in that: The main outlet pipe consists of two parallel branch pipes: the first main outlet pipe and the second main outlet pipe. The first and second outlet manifolds are connected to the outlet pipes of each heat exchanger via a single port at their common end. The other end of the first outlet manifold is connected to the outlet pipe of the battery heat exchange unit; The other end of the second outlet manifold is connected to the inlet pipe of the battery heat exchange unit.

4. The liquid cooling system of the battery circuit breaker unit according to claim 3, characterized in that: A first solenoid valve is installed on the second outlet main pipe; a second solenoid valve is installed on the inlet main pipe; and a third solenoid valve is installed on the first outlet main pipe. It also includes a control unit and a temperature sensor. The temperature sensor is in contact with the battery. The signal output terminal of the temperature sensor is electrically connected to the signal input terminal of the control unit. The signal output terminal of the control unit is electrically connected to the signal input terminals of the first solenoid valve, the second solenoid valve, and the third solenoid valve.

5. The liquid cooling system of the battery circuit breaker unit according to claim 3, characterized in that: The common end of the first and second outlet main pipes, as well as the end of the inlet main pipe that connects to each heat exchanger, all extend into the shell and the ends are closed structures. The pipe walls of the two main pipes are uniformly provided with several distribution holes along the length direction. Each distribution hole is located inside the shell and is connected to the inlet pipe of the corresponding heat exchanger.

6. The liquid cooling system of the battery circuit breaker unit according to claim 1, characterized in that: The heat exchanger body adopts a microchannel heat exchanger, and its inlet pipe and outlet pipe are respectively set on adjacent sides, opposite sides or the same side of the heat exchanger body.

7. The liquid cooling system of the battery circuit breaker unit according to claim 1, characterized in that: The heat exchanger is installed on the conductive busbar on one side of the heating device within the battery circuit breaker unit or on the body of the heating device.

8. The liquid cooling system of the battery circuit breaker unit according to claim 6, characterized in that: Heat exchangers are installed on the conductive busbars surrounding the Hall effect sensor, main negative relay, pre-charge relay, pre-charge resistor, main fuse, and main positive relay; a heat exchanger is installed on the main positive relay.

9. The liquid cooling system of the battery circuit breaker unit according to claim 6, characterized in that: The heat exchanger body is fixed to the surface of the conductive busbar and the heating element by thermally conductive structural adhesive.

10. The liquid cooling system of the battery circuit breaker unit according to claim 4, characterized in that: The battery coolant circulation system includes a heater, a cooler, a circulating water pump, and a battery heat exchange unit; the heater, cooler, circulating water pump, and battery heat exchange unit are connected by pipelines; the battery coolant flows in the pipelines; the battery heat exchange unit is in contact with the battery to exchange heat; the signal output terminal of the control unit is electrically connected to the signal input terminals of the heater, cooler, and circulating water pump.

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