A low-temperature environment power battery pack preheating device and a preheating method

Abstract

The application discloses a low-temperature environment power battery pack preheating device and a preheating method, which comprise a battery pack shell and a heat storage box, recesses are formed in the two side walls of the battery pack shell, temperature adjusting boxes are fixedly installed in the recesses, the temperature adjusting boxes are arranged at equal intervals, two air deflectors are arranged between the adjacent temperature adjusting boxes, the air deflector at the end is connected with the heat storage box, and a fan is installed at the front end of the recess. The heat storage box filled with high specific heat capacity heat storage oil liquid is arranged, and a heat exchange pipeline is arranged, so that the waste heat generated by battery heat dissipation during vehicle operation can be effectively stored. When preheating is needed, the stored heat energy is introduced into the battery pack according to needs through a three-way electromagnetic valve and the fan, the energy consumption of direct use of battery electric energy or PTC heating is greatly reduced, and the whole vehicle energy utilization efficiency is improved. The temperature sensor is arranged to realize accurate monitoring of the heat storage amount.

Description

Technical Field

[0001] This invention relates to the field of power battery pack technology, specifically to a preheating device and method for power battery packs in low-temperature environments. Background Technology

[0002] With the increasing prevalence of new energy vehicles in cold regions, the severe impact of low temperatures on the performance and lifespan of power batteries has become a critical challenge that the industry urgently needs to overcome. At low temperatures, the rate of internal chemical reactions in the battery decreases significantly, leading to a sharp increase in internal resistance, a drastic reduction in usable capacity, a decrease in charging efficiency, and potential safety hazards such as lithium deposition. Therefore, effective preheating of the battery pack is a necessary measure to ensure vehicle start-up in low temperatures, improve range, and guarantee safe operation.

[0003] Currently, mainstream battery preheating technologies mainly include the following categories: 1. Air-heated preheating: Air is heated by a PTC heater or waste heat from the motor, and then blown into the battery pack by a fan. This solution has a simple structure, but the heat density of the hot air is low, the heat transfer efficiency is not high, and there are problems such as poor temperature uniformity within the battery pack, slow preheating speed, and high energy consumption. 2. Liquid-heated preheating: Heat is conducted by heating the coolant and allowing it to flow through a liquid cooling plate inside the battery pack. This solution has high heat transfer efficiency, but the system is complex, there is a risk of leakage, and in extremely cold environments, preheating the coolant itself also requires additional energy consumption. 3. Direct electric heating: Such as placing a heating film on the surface of the battery cells. This solution has a fast response, but it is prone to uneven heating of the battery cells, generating local thermal stress, which affects battery life in the long term. Therefore, a preheating device and method for power battery packs in low-temperature environments are proposed. Summary of the Invention

[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a preheating device and method for power battery packs in low-temperature environments, which solves the comprehensive technical problems existing in current power battery low-temperature preheating technologies, such as uneven preheating, high energy consumption, single function, and low energy utilization rate between systems.

[0005] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a low-temperature environment power battery pack preheating device, comprising a battery pack shell and a heat storage box. Grooves are provided on both sides of the battery pack shell. Temperature regulating boxes are fixedly installed inside the grooves. Several temperature regulating boxes are arranged at equal intervals. Adjacent temperature regulating boxes are connected by two air guide plates. The air guide plate at the far end is connected to the heat storage box. A fan is installed at the front end of the groove. The air input end of the fan is connected to the frontmost temperature regulating box by a connecting pipe. The air output end of the fan extends into the interior of the battery pack shell. Three through holes are provided at the end of the battery pack shell. The heat storage box is fixedly installed at the end of the battery pack shell. The heat storage box has a heat storage cavity inside, which is filled with heat storage oil. A three-way solenoid valve is installed on the side wall of the heat storage box and communicates with the inside of the battery pack shell through the three-way solenoid valve. Adjustment cavities are respectively provided on both sides of the inside of the heat storage box, and adjustment mechanisms are provided inside each adjustment cavity.

[0006] As a further preferred embodiment of the present invention, a main pipe is installed on the top of the heat storage box, and the bottom two ends of the main pipe are respectively connected to the regulating cavity. Three branch pipes are installed on the side wall of the main pipe, and the ends of the branch pipes are respectively connected to the top output end of the three-way solenoid valve.

[0007] As a further preferred embodiment of the present invention, the heat storage cavity is provided with three inlet pipes, the ends of which are respectively connected to the side output end of the three-way solenoid valve. Heat exchange pipes are installed on both sides of the inlet pipes. The heat exchange pipes are U-shaped and the ends of the heat exchange pipes are fixedly connected to outlet pipes. The ends of the outlet pipes extend into the main pipe. A temperature sensor is also installed on the inner wall of the heat storage cavity.

[0008] As a further preferred embodiment of the present invention, the adjusting mechanism includes an adjusting plate, a screw, and a motor. The motor is mounted on the side wall of the heat storage box, and the power output end of the motor extends into the adjusting cavity and is connected to the screw. The screw is rotatably mounted inside the adjusting cavity and is threadedly connected to the adjusting plate. A sealing gasket is installed on the surface of the adjusting plate, and the side wall of the sealing gasket is in close contact with the inner wall of the adjusting cavity.

[0009] As a further preferred embodiment of the present invention, a positioning rod is fixedly installed at the lower end of the inner cavity of the regulating cavity. The positioning rod passes through the regulating plate and is movably connected to the regulating plate. Two connecting holes are opened on the inner wall of the regulating cavity. The connecting holes are respectively connected to the air guide plate. Filter sponges are installed on both sides of the inner cavity of the regulating cavity. The two filter sponges are respectively installed on the outside of the connecting holes and located on both sides of the regulating plate. A drain solenoid valve is installed at the bottom of the regulating cavity.

[0010] As a further preferred embodiment of the present invention, a semiconductor cooling chip is installed in the middle of the temperature regulating box. The semiconductor cooling chip divides the interior of the temperature regulating box into a cold cavity and a hot cavity. The cold end of the semiconductor cooling chip is located in the cold cavity and the cold cavity is close to the battery pack shell. The hot end of the semiconductor cooling chip is located in the hot cavity.

[0011] As a further preferred embodiment of the present invention, air guide blocks are installed on the inner walls of both the cold cavity and the hot cavity, and the air guide blocks are in the form of isosceles trapezoids.

[0012] As a further preferred embodiment of the present invention, return air pipes are respectively installed on both sides of the inner wall of the battery pack casing, the end of the return air pipes is connected to the wind power output end of the fan, and a plurality of nozzles are provided on the side wall of the return air pipes.

[0013] As a further preferred embodiment of the present invention, the air guide plate has a plurality of air guide holes equidistantly arranged inside, and a diversion hole is connected between adjacent air guide holes.

[0014] A method for preheating a power battery pack in a low-temperature environment, based on the low-temperature power battery pack preheating device according to any one of claims 1-9, includes the following steps: S1: Status judgment: Monitor the battery pack temperature and the heat storage box temperature. When the battery pack temperature is lower than the preset threshold, preheating is started. S2: Mode Selection and Cooperative Execution: Select the preheating mode based on the temperature of the thermal storage tank. If the temperature of the heat storage box is higher than that of the battery pack and reaches the usable heat standard, the waste heat recovery mode is activated: the three-way solenoid valve is controlled to introduce the air in the battery pack into the heat exchange tube in the heat storage chamber for heating, and at the same time the fan drives the hot air to circulate into the battery pack through the temperature control box air duct. If the heat storage is insufficient or rapid heating is required, the active heating mode will be activated simultaneously or independently: the hot end of the semiconductor cooling chip in the temperature control box will be turned on to directly heat the air flowing through it. S3: Dynamic adjustment: During the preheating process, the airflow ratio to different air ducts is dynamically allocated by moving the adjustment plate of the adjustment mechanism, and combined with the independent temperature control of the temperature control box, the internal temperature difference of the battery pack is reduced. S4: Termination: When the battery pack temperature reaches the target temperature and is evenly distributed, preheating stops, the regulating plate of the regulating mechanism moves, and it switches to cooling mode. (III) Beneficial Effects This invention provides a preheating device and method for power battery packs in low-temperature environments. It has the following beneficial effects: This system achieves efficient energy storage and on-demand utilization, significantly reducing system energy consumption: By setting up a heat storage tank filled with high-specific-heat-capacity thermal storage oil and configuring heat exchange pipelines, it can effectively store waste heat generated by battery dissipation during vehicle operation. When preheating is required, the stored heat energy is introduced into the battery pack on demand through a three-way solenoid valve and a fan, greatly reducing the energy consumption of directly using battery power or PTC heating, and improving the overall vehicle energy utilization efficiency. The installation of temperature sensors enables precise monitoring of the stored heat.

[0015] It provides active, uniform, and finely adjustable preheating / cooling capabilities: multiple temperature-regulating boxes with integrated semiconductor cooling chips are arranged equidistantly on both sides of the battery pack, forming an independent and controllable microenvironment temperature control unit. By switching the current direction of the semiconductor cooling chips, the same device can actively heat or cool the battery sidewalls. Combined with a parallel air duct system consisting of a fan and air guide plates, and the guiding effect of the air guide blocks, cold or hot air can be evenly delivered to the inside of the battery pack, effectively solving the problem of uneven temperature distribution in traditional solutions and improving thermal management and battery consistency.

[0016] A flexible and intelligent multi-mode thermal management path has been constructed: through the coordinated design of a three-way solenoid valve, an adjustment mechanism (motor-driven screw drives the adjustment plate) and multiple connecting ventilation ducts, the system can intelligently switch working modes according to the battery temperature status and requirements.

[0017] Preheating mode: Hot air is drawn from the heat storage tank or the semiconductor cooling chip is activated to heat the battery pack.

[0018] Heat dissipation mode: The semiconductor cooling chip is activated to cool the battery pack and send cool air into the battery pack. At the same time, the regulating plate can control part of the airflow to exchange heat with the heat storage chamber. Attached Figure Description

[0019] Figure 1 This is a structural diagram of the low-temperature environment power battery pack preheating device and preheating method described in this invention; Figure 2 This is an external structural diagram of the heat storage box described in this invention; Figure 3 This is a diagram showing the internal structure of the heat storage box described in this invention; Figure 4 This is an external structural diagram of the temperature control box described in this invention; Figure 5 This is a diagram showing the internal structure of the temperature control box described in this invention; Figure 6 This is a diagram showing the internal structure of the battery pack casing of the present invention.

[0020] In the diagram: 1. Battery pack casing; 2. Heat storage box; 3. Groove; 4. Temperature control box; 5. Air guide plate; 6. Fan; 7. Branch pipe; 8. Main pipe; 9. Three-way solenoid valve; 10. Outlet pipe; 11. Temperature sensor; 12. Heat storage chamber; 13. Inlet pipe; 14. Heat exchange tube; 15. Adjusting plate; 16. Screw; 17. Motor; 18. Connection hole; 19. Filter sponge; 20. Positioning rod; 21. Sealing gasket; 22. Drain solenoid valve; 23. Semiconductor cooling chip; 24. Air guide hole; 25. Diverter hole; 26. Air guide block; 27. Through hole; 28. Return air pipe; 29. ​​Nozzle. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figure 1-6 This invention provides a technical solution: a low-temperature environment power battery pack preheating device, including a battery pack shell 1 and a heat storage box 2. Grooves 3 are provided on both side walls of the battery pack shell 1. Temperature regulating boxes 4 are fixedly installed inside the grooves 3. Several temperature regulating boxes 4 are arranged at equal intervals. Adjacent temperature regulating boxes 4 are connected by two air guide plates 5. The air guide plate 5 at the far end is connected to the heat storage box 2. A fan 6 is installed at the front end of the grooves 3. The air input end of the fan 6 is connected to the frontmost temperature regulating box 4 via a connecting pipe. The air output end of the fan 6 extends into the interior of the battery pack shell 1. Three through holes 27 are provided at the end of the battery pack shell 1. The heat storage box 2 is fixedly installed at the end of the battery pack shell 1. A heat storage chamber 12 is provided inside the heat storage box 2. The heat storage chamber 12 is filled with heat storage oil. A three-way solenoid valve 9 is installed on the side wall of the heat storage box 2 and communicates with the interior of the battery pack shell 1 through the three-way solenoid valve 9. Adjustment chambers are provided on both sides of the interior of the heat storage box 2, and adjustment mechanisms are provided inside each adjustment chamber. By physically coupling the three major functional modules of active temperature control (temperature control box 4), air circulation (fan 6, air guide plate 5), and waste heat storage / utilization (heat storage box 2), a comprehensive solution framework for power batteries that combines preheating, heat dissipation, and energy recovery is provided. The system has a high degree of integration and saves layout space. Further improvements include a main pipe 8 installed at the top of the thermal storage tank 2, with its bottom ends connected to the regulating chambers. Three branch pipes 7 are installed on the side wall of the main pipe 8, with their ends connected to the top output of the three-way solenoid valve 9. By connecting the top main pipe 8 to the regulating chambers on both sides and the three branch pipes 7 to the three-way solenoid valve 9, a centralized airflow distribution hub is established. This structure simplifies the piping layout, allowing the airflow from the three-way solenoid valve 9 (whether from inside the battery pack or the thermal storage chamber 12) to be conveniently and controllably distributed to the regulating chambers on both sides via the main pipe 8, achieving airflow convergence and redistribution, and laying the foundation for subsequent precise adjustment.

[0023] Further improvements include three inlet pipes 13 inside the heat storage chamber 12. The ends of the inlet pipes 13 are connected to the side output ends of the three-way solenoid valve 9. Heat exchange pipes 14 with a U-shaped structure are installed on both sides of the inlet pipes 13. An outlet pipe 10 is fixedly connected to the end of the heat exchange pipe 14, and the end of the outlet pipe 10 extends into the main pipe 8. A temperature sensor 11 is also installed on the inner wall of the heat storage chamber 12. The U-shaped heat exchange pipe 14 significantly extends the heat exchange path and time between the airflow and the heat storage oil, thereby greatly improving the efficiency and rate of waste heat storage or release. The temperature sensor 11 can monitor the temperature of the heat storage oil in real time and accurately, providing key data input for the system to intelligently judge the heat storage status and switch the working mode.

[0024] Further improvements include an adjustment plate 15, a screw 16, and a motor 17. The motor 17 is mounted on the side wall of the heat storage tank 2. The power output end of the motor 17 extends into the adjustment cavity and is connected to the screw 16. The screw 16 is rotatably mounted inside the adjustment cavity and threadedly connected to the adjustment plate 15. A sealing gasket 21 is installed on the surface of the adjustment plate 15, and the side wall of the sealing gasket 21 is in close contact with the inner wall of the adjustment cavity. The adjustment mechanism uses a design where the motor 17 drives the screw 16, which in turn drives the adjustment plate 15 with the sealing gasket 21 to make linear motion. Its advantage is that it realizes stepless, precise, and reliable mechanical adjustment of the opening and closing size or ratio of the air duct in the adjustment cavity. The sealing gasket 21 ensures the sealing of the adjustment plate 15 at different positions, preventing airflow short-circuiting, thereby enabling precise control of the airflow ratio to different targets (such as to the battery pack or for heat exchange), adapting to complex thermal management needs.

[0025] Further improvements include a positioning rod 20 fixedly installed at the lower end of the regulating cavity, which passes through and is movably connected to the regulating plate 15. Two connection holes 18 are formed on the inner wall of the regulating cavity, communicating with the air guide plate 5. Filter sponges 19 are installed on both sides of the regulating cavity, respectively, outside the connection holes 18 and located on both sides of the regulating plate 15. A drain solenoid valve 22 is installed at the bottom of the regulating cavity. The regulating plate 15 opens / closes the corresponding connection holes 18. The filter sponges 19 filter water vapor and particles in the circulating air. During the movement of the regulating plate 15, the filter sponges 19 are squeezed, squeezing out the water inside, which is then drained through the drain solenoid valve 22.

[0026] Further improvements include a thermoelectric cooler 23 installed in the middle of the temperature control box 4. The thermoelectric cooler 23 divides the interior of the temperature control box 4 into a cold cavity and a hot cavity, with the cold end of the thermoelectric cooler 23 located in the cold cavity, which is close to the battery pack casing 1, and the hot end of the thermoelectric cooler 23 located in the hot cavity. Installing the thermoelectric cooler 23 in the middle of the temperature control box 4 and separating its cold and hot ends into the cold and hot cavities respectively provides the system with bidirectional active temperature control capabilities. By simply changing the direction of the current, the same device can achieve heating (hot cavity operation) or cooling (cold cavity operation), thus flexibly handling two completely different operating conditions: low-temperature preheating and high-temperature heat dissipation. This replaces the traditional independent heating and cooling systems, simplifies the structure, and improves the response speed.

[0027] Further improvements include the installation of air guide blocks 26 on the inner walls of both the cold and hot chambers. These air guide blocks 26 are isosceles trapezoidal in shape. Installing isosceles trapezoidal air guide blocks 26 on the inner walls of the cold and hot chambers effectively guides the airflow smoothly through the chambers, reducing eddies and dead zones, ensuring sufficient and uniform heat exchange between the airflow and the cold or hot end surface of the semiconductor cooling chip 23, thereby improving the efficiency of temperature rise or fall of the air in a single flow.

[0028] Further improvements include the installation of return air ducts 28 on both sides of the inner wall of the battery pack casing 1. The ends of the return air ducts 28 are connected to the air output end of the fan 6, and several nozzles 29 are installed on the side walls of the return air ducts 28. The beneficial effect of having return air ducts 28 connected to the output end of the fan 6 on the inner wall of the battery pack casing 1, and multiple nozzles 29 arranged on them, is the creation of a forced circulation air duct. The airflow driven by the fan 6, after passing through the temperature control box 4 or being heated / cooled by the heat storage box 2, is evenly blown onto the battery modules through the nozzles 29, and then flows back through the through-holes 27 at the end of the battery pack casing 1, and may eventually be drawn back into the system for recirculation. This greatly enhances the temperature uniformity inside the battery pack, avoiding localized overheating or overcooling.

[0029] Further improvements include the inclusion of several equidistant air guide holes 24 within the air guide plate 5, with diversion holes 25 connecting adjacent air guide holes 24. The beneficial effect of having air guide holes 24 and connecting diversion holes 25 within the air guide plate 5 is the achievement of refined airflow distribution and uniform flow. This allows the airflow to be divided into multiple fine streams as it passes through the air guide plate 5, and the pressure is distributed within the plate through the diversion holes 25. This ensures a more uniform airflow volume from each air guide hole 24, thereby guaranteeing a balanced airflow supply to each temperature control box 4 or air intake area along the length of the battery pack. This is a key structure for improving overall temperature consistency.

[0030] A method for preheating a power battery pack in a low-temperature environment includes the following steps: S1: Status judgment: Monitor the battery pack temperature and the temperature of the heat storage box 2. When the battery pack temperature is lower than the preset threshold, preheating is started. S2: Mode Selection and Cooperative Execution: Select the preheating mode based on the temperature of heat storage tank 2. If the temperature of the heat storage box 2 is higher than the temperature of the battery pack and reaches the usable heat standard, the waste heat recovery mode is activated: control the three-way solenoid valve 9 to introduce the air in the battery pack into the heat exchange tube 14 in the heat storage chamber 12 for heating, and at the same time the fan 6 drives the hot air to circulate into the battery pack through the air duct of the temperature control box 4. If the heat storage is insufficient or rapid heating is required, the active heating mode is activated simultaneously or independently: the hot end of the semiconductor cooling chip 23 in the temperature control box 4 is turned on to directly heat the flowing air. S3: Dynamic adjustment: During the preheating process, the airflow ratio to different air ducts is dynamically allocated by moving the adjustment plate 15 of the adjustment mechanism, and combined with the independent temperature control of the temperature control box 4, the internal temperature difference of the battery pack is reduced. S4: Termination: When the battery pack temperature reaches the target temperature and is evenly distributed, preheating stops, and the adjustment plate 15 of the adjustment mechanism moves to adjust to cooling mode.

[0031] Working principle: 1. System initialization and status monitoring After the vehicle is powered on or the battery management system is activated, the preheating device starts. The system first collects key sensor data, including: the temperature of multiple monitoring points inside the battery pack; the temperature of the heat storage oil in the heat storage chamber 12; and the state of charge of the battery pack.

[0032] 2. Preheating Demand Assessment and Model Decision Compare the lowest temperature of the battery pack with a preset preheating trigger threshold (e.g., 0°C): If the lowest temperature of the battery pack is greater than or equal to the threshold, it is determined that no preheating is required, and the battery enters hibernation or temperature maintenance mode.

[0033] If the battery pack's minimum temperature is below the threshold, preheating is required, and the mode decision logic is initiated. Prioritize the waste heat utilization conditions: If the temperature of the heat storage oil in the heat storage chamber 12 is higher than the minimum temperature of the battery pack and the temperature difference exceeds the set value (e.g., 5°C), then prioritize entering the "waste heat recovery preheating main mode".

[0034] Auxiliary / rapid heating judgment: If the temperature of the heat storage oil in the heat storage chamber 12 is insufficient, or if the conditions are met but rapid heating is required, the decision is made to simultaneously or subsequently activate the "active electric heating auxiliary mode".

[0035] 3. Multi-mode collaborative preheating execution Based on the decision made in step 2, execute the corresponding preheating process: 3.1 Waste heat recovery preheating main mode execution Airflow switching: Control the three-way solenoid valve 9 to connect the through hole 27 at the end of the battery pack outer shell 1 with the inlet pipe 13 of the heat storage chamber 12, while closing or reducing the branch pipe 7 leading to the main pipe 8.

[0036] Waste heat exchange: When the fan 6 is started, the cold air inside the battery pack is drawn out through the through hole 27 and enters the inlet pipe 13 and U-shaped heat exchange pipe 14 in the heat storage chamber 12 through the three-way solenoid valve 9. The cold air undergoes full heat exchange with the high-temperature heat storage oil and is rapidly heated.

[0037] Heat transfer: Heated air flows out from the outlet pipe 10 of the heat exchange tube 14 and enters the main pipe 8. The regulating mechanism in the regulating chambers on both sides is controlled to open the passage leading to the connecting hole 18 of the air guide plate 5. After being distributed by the regulating chamber, the hot air is evenly delivered to all temperature regulating boxes 4 through each air guide plate 5 (at this time, the semiconductor cooling chip 23 is usually not working).

[0038] Circulating heating: Finally, under the negative pressure of fan 6, all the hot air is collected through the connecting pipe and drawn into fan 6, and then pumped into return air pipe 28 from the fan 6's air output end. It is then evenly blown onto the surface of the battery module through nozzle 29, completing one heating cycle. This process continues, forming a closed hot air circulation.

[0039] 3.2 Active electric heating auxiliary mode is executed. Activate the active heat source: control the semiconductor cooling chip 23 in all or designated areas of the temperature control box 4 to be energized, so that its hot end works (heat is generated on the hot cavity side).

[0040] Airflow configuration: Adjust the three-way solenoid valve 9 and / or the regulating mechanism to ensure that the airflow mainly passes through the hot cavity of the temperature control box 4. As the air flows through the hot cavity, it is directly heated by the hot end of the semiconductor cooling chip 23.

[0041] Collaborative or independent operation: This mode can operate in conjunction with the waste heat recovery mode (in which case the air flowing through the hot chamber is "reheated"), or operate independently when waste heat is insufficient. The heated air is also blown to the battery through the circulating air path driven by fan 6.

[0042] 4. Dynamic adjustment and optimization of the preheating process During the preheating process, the system makes real-time dynamic adjustments to optimize the effect: Uniformity adjustment: Based on the temperature difference of each monitoring point in the battery pack, the air volume of different air ducts is dynamically distributed by controlling the heating power of the temperature control box 4 in different areas (adjusting the current of the semiconductor cooling chip 23) and / or adjusting the opening of the adjustment mechanism of the corresponding air guide plate 5, so as to reduce the temperature difference in the battery pack.

[0043] Energy efficiency optimization and regulation: Real-time monitoring of the temperature drop of the heat storage oil in the heat storage chamber 12. When the temperature of the heat storage oil in the heat storage chamber 12 drops to near the internal temperature of the battery pack, the system gradually reduces its reliance on the waste heat recovery mode and smoothly transitions to the active electric heating mode as the main mode to avoid inefficient heat exchange.

[0044] Fan speed adjustment: Adjust the fan speed according to the preheating stage (rapid heating period, heat preservation period) to balance heating speed and energy consumption.

[0045] 5. Preheating terminated When the minimum temperature of the battery pack reaches or exceeds the preset target operating temperature (e.g., 10-15℃), and the maximum temperature difference within the battery pack is within the allowable range, preheating is considered complete. The system sequentially shuts down the thermoelectric cooler 23 and the fan 6, and resets the three-way solenoid valve 9 and the regulating mechanism to their default states, ending the preheating process. The thermoelectric cooler 23, fan 6, three-way solenoid valve 9, and regulating mechanism can participate in the cooling process during the daily use of the battery pack.

[0046] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0047] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A low-temperature environment power battery pack preheating device, comprising a battery pack shell (1) and a heat storage box (2), characterized in that: The battery pack housing (1) has grooves (3) on both sides of its outer wall. Temperature control boxes (4) are fixedly installed inside the grooves (3). Several temperature control boxes (4) are arranged and distributed at equal intervals. Adjacent temperature control boxes (4) are connected by two air guide plates (5). The air guide plate (5) at the end is connected to the heat storage box (2). A fan (6) is installed at the front end of the groove (3). The air input end of the fan (6) is connected to the front end temperature control box (4) by a connecting pipe. The air output end of the fan (6) extends into the interior of the battery pack housing (1). Three through holes (27) are opened at the end of the battery pack housing (1). The heat storage box (2) is fixedly installed at the end of the battery pack shell (1). The heat storage box (2) is provided with a heat storage chamber (12), which is filled with heat storage oil. A three-way solenoid valve (9) is installed on the side wall of the heat storage box (2) and is connected to the inside of the battery pack shell (1) through the three-way solenoid valve (9). Adjustment chambers are provided on both sides of the inside of the heat storage box (2), and adjustment mechanisms are provided inside each adjustment chamber.

2. The low-temperature environment power battery pack preheating device according to claim 1, characterized in that: The top of the heat storage box (2) is equipped with a main pipe (8), and the bottom two ends of the main pipe (8) are respectively connected to the regulating cavity. Three branch pipes (7) are installed on the side wall of the main pipe (8), and the ends of the branch pipes (7) are respectively connected to the top output end of the three-way solenoid valve (9).

3. The low-temperature environment power battery pack preheating device according to claim 1, characterized in that: The heat storage chamber (12) is provided with three inlet pipes (13). The ends of the inlet pipes (13) are connected to the side output end of the three-way solenoid valve (9). Heat exchange pipes (14) are installed on both sides of the inlet pipes (13). The heat exchange pipes (14) are U-shaped. The ends of the heat exchange pipes (14) are fixedly connected to the outlet pipes (10). The ends of the outlet pipes (10) extend into the main pipe (8). Temperature sensors (11) are also installed on the inner wall of the heat storage chamber (12).

4. The low-temperature environment power battery pack preheating device according to claim 1, characterized in that: The adjustment mechanism includes an adjustment plate (15), a screw (16) and a motor (17). The motor (17) is installed on the side wall of the heat storage box (2). The power output end of the motor (17) extends into the adjustment cavity and is connected to the screw (16). The screw (16) is rotatably installed inside the adjustment cavity and is threadedly connected to the adjustment plate (15). A sealing gasket (21) is installed on the surface of the adjustment plate (15). The side wall of the sealing gasket (21) is in close contact with the inner wall of the adjustment cavity.

5. The low-temperature environment power battery pack preheating device according to claim 1, characterized in that: A positioning rod (20) is fixedly installed at the lower end of the regulating cavity. The positioning rod (20) passes through the regulating plate (15) and is movably connected to the regulating plate (15). Two connecting holes (18) are opened on the inner wall of the regulating cavity. The connecting holes (18) are respectively connected to the air guide plate (5). Filter sponges (19) are installed on both sides of the inner cavity. The two filter sponges (19) are respectively installed on the outside of the connecting holes (18) and located on both sides of the regulating plate (15). A drain solenoid valve (22) is installed at the bottom of the regulating cavity.

6. The low-temperature environment power battery pack preheating device according to claim 1, characterized in that: A semiconductor cooling chip (23) is installed in the middle of the temperature control box (4). The semiconductor cooling chip (23) divides the interior of the temperature control box (4) into a cold cavity and a hot cavity. The cold end of the semiconductor cooling chip (23) is located in the cold cavity and the cold cavity is close to the battery pack shell (1). The hot end of the semiconductor cooling chip (23) is located in the hot cavity.

7. A low-temperature environment power battery pack preheating device according to claim 6, characterized in that: Air guide blocks (26) are installed on the inner walls of both the cold cavity and the hot cavity. The air guide blocks (26) are in the shape of an isosceles trapezoid.

8. The low-temperature environment power battery pack preheating device according to claim 1, characterized in that: The inner walls of the battery pack housing (1) are respectively equipped with return air pipes (28), the end of the return air pipes (28) is connected to the wind power output end of the fan (6), and a number of nozzles (29) are provided on the side wall of the return air pipes (28).

9. A low-temperature environment power battery pack preheating device according to claim 1, characterized in that: The air guide plate (5) has several air guide holes (24) equidistantly arranged inside, and a diversion hole (25) is connected between adjacent air guide holes (24).

10. A method for preheating a power battery pack in a low-temperature environment, based on the low-temperature power battery pack preheating device according to any one of claims 1-9, characterized in that, Includes the following steps: S1: Status judgment: Monitor the battery pack temperature and the heat storage box temperature. When the battery pack temperature is lower than the preset threshold, preheating is started. S2: Mode Selection and Cooperative Execution: Select the preheating mode based on the temperature of the thermal storage tank. If the temperature of the heat storage box is higher than that of the battery pack and reaches the usable heat standard, the waste heat recovery mode is activated: the three-way solenoid valve is controlled to introduce the air in the battery pack into the heat exchange tube in the heat storage chamber for heating, and at the same time the fan drives the hot air to circulate into the battery pack through the temperature control box air duct. If the heat storage is insufficient or rapid heating is required, the active heating mode will be activated simultaneously or independently: the hot end of the semiconductor cooling chip in the temperature control box will be turned on to directly heat the air flowing through it. S3: Dynamic adjustment: During the preheating process, the airflow ratio to different air ducts is dynamically allocated by moving the adjustment plate of the adjustment mechanism, and combined with the independent temperature control of the temperature control box, the internal temperature difference of the battery pack is reduced. S4: Termination: When the battery pack temperature reaches the target temperature and is evenly distributed, preheating stops, the adjustment plate of the adjustment mechanism moves, and it is adjusted to cooling mode.

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