Phase change cold storage type vehicle-mounted charging device

Abstract

The invention relates to the technical field of electric vehicle charging, in particular to a phase change cold storage type vehicle-mounted charging device which comprises the following cooperative work modules: a composite phase change cold storage module comprising a multi-cavity honeycomb structure; the gradient flow channel unit is integrated in the composite phase change cold storage module, a secondary refrigerant flow channel adopts a variable cross-section multi-return-stroke design, the height of the cross section of the flow channel is decreased progressively in the flowing direction, and the density of corrugated plate fins is increased progressively in the flowing direction; the two-stage cooling capacity distribution module comprises a first-stage conical throttle valve and a second-stage micro-channel heat transfer pipe; the vehicle-mounted coupling heat management module is used for switching a phase change cooling loop and a vehicle-mounted air conditioner loop through an electromagnetic three-way valve and additionally arranging a check valve on a secondary refrigerant outlet pipe of a charging pile, so that a cold storage mechanism of pre-charging cold by using valley electricity is realized; and an intelligent control module. By combining the phase change material, the gradient flow channel design, the intelligent control algorithm and the secondary cooling capacity distribution strategy, the device effectively reduces the temperature rise in the battery charging process, ensures the charging safety and optimizes the energy utilization.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle charging, and in particular to a phase-change cold storage type vehicle-mounted charging device. Background Art

[0002] With the widespread adoption of DC fast-charging technology for electric vehicles (charging rate ≥ 4C), power batteries face severe thermal management challenges during fast charging. Existing thermal management systems have the following technical deficiencies that need to be addressed: 1. Fast charging temperature rise out of control problem; During high-rate charging, the delayed diffusion rate of lithium ions in the electrode solid phase leads to increased polarization, and the battery's instantaneous heat generation can reach 5-8 times that of conventional charging. Traditional liquid cooling systems, due to delayed thermal response (>30 seconds), are unable to promptly suppress localized temperature rises in the battery cell, causing hotspot temperatures to exceed 60°C. Experiments have shown that if the peak temperature during a single fast charge exceeds 45°C, the battery capacity decay rate will increase by over 40%. If it exceeds 60°C, the SEI film decomposition reaction will accelerate, potentially leading to thermal runaway.

[0003] 2. Battery pack temperature gradient imbalance problem; The individual cells in the battery pack have significant temperature differences due to position differences (such as edge and center cells), manufacturing process fluctuations (such as electrode coating thickness errors), and uneven contact thermal resistance. Existing air cooling / liquid cooling systems are difficult to achieve uniform heat dissipation: Liquid cooling plates usually use a serpentine flow channel design, resulting in a temperature difference of >15°C between the coolant inlet and outlet areas; When the temperature difference between battery cells is greater than 10°C, the internal resistance difference increases, triggering a circulation effect, accelerating the overcharging and aging of low-resistance batteries and the undercharging and capacity loss of high-resistance batteries, shortening the overall life by 30%.

[0004] Therefore, there is an urgent need for a phase change cold storage vehicle-mounted charging device to solve the above problems. Summary of the Invention

[0005] Based on the above objectives, the present invention provides a phase change cold storage vehicle charging device, including the following modules working in conjunction with each other: The composite phase-change cold storage module includes a multi-cavity honeycomb structure, which is formed by welding corrugated plates and connecting plates to form a phase-change material storage space, and the interior is filled with composite phase-change material. The openings in the connecting plates connect adjacent honeycomb cavities, and the capillary force drives the liquid phase-change material to flow. The gradient flow channel unit is integrated into the composite phase change cold storage module. The refrigerant flow channel adopts a variable cross-section multi-return design. The cross-sectional height of the flow channel decreases along the flow direction, and the density of the corrugated plate fin increases along the flow direction. A two-stage cooling distribution module includes a first-stage conical throttle valve and a second-stage microchannel heat transfer tube. The conical throttle valve is installed on the inlet manifold and dynamically adjusts the branch flow rate based on the refrigerant inlet pressure. The inner wall of the microchannel heat transfer tube is coated with a carbon nanotube coating and is hard-connected to the battery cooling plate via a quick-connect connector. The vehicle-mounted coupled thermal management module switches the phase-change cooling circuit and the vehicle air conditioning circuit via a solenoid three-way valve. A check valve is added to the refrigerant outlet pipe of the charging pile to implement a cold storage mechanism that utilizes valley electricity for pre-charging. The intelligent control module dynamically adjusts the coolant flow rate and circuit switching logic based on the phase change material deformation data detected by the battery surface temperature sensor, coolant flow meter and resistance strain gauge, and simultaneously implements the residual cold recovery strategy after charging is completed.

[0006] Preferably, the gradient channel unit's flow channel cross-sectional height decrease rate is dynamically adjusted based on feedback values ​​of the brine inlet pressure and outlet flow rate to ensure that the terminal flow rate is not lower than the critical flow rate for preventing local solidification of the phase change material; the corrugated plate fin density increase rate is determined by experimentally calibrating the balance between the heat exchange efficiency and pressure drop at the end of the flow channel, specifically including: Establish a heat exchange efficiency model for the final section of the flow channel. Input parameters include the specific heat capacity of the refrigerant, the latent heat release rate of the phase change material, and the ambient temperature fluctuation range. Through prototype testing of variable fin density, heat exchange efficiency and pressure drop data at different densities were collected; With the constraints of heat exchange efficiency decrease rate ≤ 10% and pressure rise increase rate ≤ 15%, the optimal range of fin density increase rate was fitted.

[0007] Preferably, the connected pore diameter of the multi-cavity honeycomb structure is determined by capillary force model calculation, specifically including: Measure the surface tension coefficient and density of the composite phase change material in liquid state, and calculate the basic pore diameter in combination with the gravitational acceleration; The material wettability correction coefficient is calibrated through contact angle experiments. The correction coefficient is negatively correlated with the wetting angle of the phase change material to the connected plate. The final connected pore diameter is generated based on the product of the basic pore diameter and the correction coefficient to ensure that the flow rate driven by the capillary force matches the heat absorption rate of the coolant.

[0008] Preferably, the number of microchannels of the secondary microchannel heat transfer tube is determined based on a unit time cooling demand distribution model, and the model input parameters include: The peak heating power of the battery pack is calculated by multiplying the battery charge and discharge rate by the internal resistance; The latent heat release rate of the phase change material is obtained by multiplying the solidification ratio by the total latent heat value in real time; The ambient temperature compensation coefficient is obtained by mapping the temperature-heat dissipation efficiency curve based on the historical data of the vehicle temperature control system.

[0009] Preferably, the intelligent control module executes the following control logic: When the difference between the maximum and minimum temperatures of the battery pack exceeds a preset temperature difference threshold, the variable flow pump is activated to adjust the coolant flow. The adjustment range is dynamically generated based on the temperature difference suppression efficiency mapping table trained with historical charging data. When the maximum battery temperature exceeds the phase change cooling activation threshold, the system switches to the phase change cooling circuit and increases the flow rate. The activation threshold is dynamically adjusted according to the real-time solidification ratio of the phase change material: the lower the solidification ratio, the lower the activation threshold is to start strong cooling earlier. After charging is completed, the duration and air volume of the vehicle air-conditioning fan extracting cold air are controlled based on the residual cooling capacity of the phase change module and the target temperature drop value of the passenger compartment.

[0010] Preferably, the adjustment amplitude of the variable flow pump is dynamically generated by the following process: A mapping table between coolant flow rate and temperature difference suppression efficiency was constructed, and a neural network model was trained on historical charging data. Input variables included battery pack temperature distribution variance, ambient humidity, and charging current rate. Collect battery pack temperature distribution variance in real time and obtain humidity data through on-board environmental sensors; The input variables are imported into the trained neural network model to output the optimal flow regulation ratio. The regulation direction is in the same direction as the positive and negative values ​​of the temperature distribution variance.

[0011] Preferably, the composite phase change material is a paraffin-based composite material, and its component ratio is determined by orthogonal test optimization: Taking the maximization of latent heat value and the achievement of thermal conductivity as the optimization goals, a three-factor five-level orthogonal table of paraffin wax, expanded graphite, and epoxy resin was set up; The latent heat value, thermal conductivity and viscosity under different ratios were tested, and the viscosity was continuously measured within the phase change temperature range using a rotational viscometer; The optimal ratio of comprehensive performance is calculated by weighted scoring method, with the latent heat value weight ≥ 70% and the thermal conductivity coefficient weight ≤ 30%.

[0012] Preferably, the critical value of the insertion and extraction force of the quick connect connector is determined by a vibration adaptability test: Simulate vehicle vibration spectrum and test joint sealing performance on a vibration table with a frequency of 5–200 Hz and an acceleration of 3g; Gradually increase the insertion and extraction force until the leakage rate exceeds the sealing threshold, and record the critical insertion and extraction force for leakage; Set 90% of the critical insertion and extraction force as the upper limit of the connector design insertion and extraction force.

[0013] Preferably, the activation conditions of the cold storage mechanism using valley electricity pre-charging include: When the real-time electricity price of the power grid is lower than the preset electricity price threshold, the data of the power market trading platform is obtained through the charging pile communication module; The remaining cold storage capacity of the phase change material is lower than the safety margin threshold, which is calculated by fitting the deformation sensor data with the solidification ratio model; The next planned charging time interval is greater than the effective duration of cold storage, which is determined by the time difference between the travel nodes predicted by the on-board navigation system.

[0014] Preferably, the safety margin threshold is dynamically calculated by the following process: Calculate the correlation between the average temperature rise rate of the battery pack and the cooling coefficient of the phase change material during the historical charging cycle; Correct the predicted temperature rise rate based on the current battery health status; With the constraint of maintaining safe temperature control for the next charging cycle, the required minimum cold storage capacity is reversed, and 120% of it is set as the safety margin threshold.

[0015] Beneficial effects of the present invention: 1. By incorporating a composite phase-change cold storage module and an intelligent control module, this invention utilizes phase-change materials to absorb significant amounts of charging heat during the charging process, thus avoiding the inherent inability of traditional liquid cooling systems to respond promptly. Specifically, the instant switching and flow regulation of the phase-change cooling circuit rapidly suppresses localized temperature rises in the battery pack, preventing hotspots from exceeding 60°C. This effectively slows the rate of battery capacity decay and prevents thermal runaway caused by excessive temperatures, thereby enhancing battery safety and service life.

[0016] 2. The gradient flow channel unit design of the present invention utilizes a variable-cross-section, multi-pass coolant flow channel, enabling adaptive adjustment of the coolant flow rate and flow path based on the thermal requirements of the battery pack. In particular, the decreasing flow channel cross-section and increasing corrugated fin density minimize temperature differences and achieve uniform heat dissipation. Furthermore, the secondary cooling capacity distribution module precisely distributes cooling capacity, ensuring temperature balance among individual battery cells, preventing overcharging and undercharging caused by internal resistance differences between cells and significantly extending the overall battery life.

[0017] 3. This invention utilizes an intelligent control module to dynamically adjust coolant flow and circuit switching based on real-time data from battery surface temperature sensors and coolant flowmeters. This module precisely adjusts the cooling strategy based on battery pack temperature distribution, coolant flow, and battery heating, ensuring a rapid response to temperature rises during fast charging. This significantly improves the system's response speed and regulation accuracy, preventing overheating.

[0018] 4. The phase-change cooling system in this invention pre-stores cold energy through a valley-time pre-charging cold storage mechanism. Combined with the onboard coupled thermal management module's check valve and electromagnetic three-way valve switching technology, this ensures flexible switching of the cooling circuit based on battery temperature changes during charging. This not only improves cooling efficiency but also effectively reduces the thermal load on the battery from the air conditioning system, lowering energy consumption. This highly efficient cold energy distribution and storage mechanism ensures energy-efficient operation of the system while ensuring battery temperature control. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0020] Figure 1 This is a schematic diagram of module connections of the device of the present invention; Figure 2 A flow chart showing the steps for calculating the connected pore diameter of a multi-cavity honeycomb structure in the device of the present invention; Figure 3 This is a fast charging temperature rise comparison curve of the present invention. DETAILED DESCRIPTION

[0021] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It is also noted that, to provide a more detailed description, the following embodiments are best and preferred embodiments, and those skilled in the art may employ alternative methods for implementing certain known technologies. Furthermore, the accompanying drawings are intended only to provide a more detailed description of the embodiments and are not intended to limit the present invention.

[0022] See Figure 1-Figure 3 , an embodiment of the present invention provides a phase-change cold storage on-board charging device. The composite phase-change cold storage module adopts a multi-cavity honeycomb structure. A plurality of phase-change material storage spaces are formed by welding corrugated plates and connecting plates, and the interior is filled with composite phase-change materials. The composite phase-change material can absorb the heat generated by battery charging during the charging process and effectively control the temperature through the phase change process. The openings in the connecting plate connect the adjacent honeycomb cavities, and use capillary force to promote the flow of liquid phase-change materials, thereby enhancing the efficiency of heat exchange. Through this design, a rapid response can be achieved and the local temperature rise of the battery can be suppressed, avoiding battery attenuation or thermal runaway due to high temperature. The application of phase change materials effectively improves the response speed of thermal management, ensures that the temperature does not rise rapidly, and guarantees the charging safety of the battery.

[0023] The gradient flow channel unit is integrated into the composite phase change cold storage module, and the coolant flow channel adopts a variable cross-section multi-return design. The height of the flow channel cross section decreases along the flow direction, while the density of the corrugated plate fins increases along the flow direction. This design can accurately adjust the flow path of the fluid according to the changes in battery temperature, so that the coolant can be more efficiently distributed in the battery pack, avoiding the situation of excessive coolant temperature difference and insufficient local heat dissipation in traditional liquid cooling systems, thereby improving the overall heat dissipation efficiency. Through this optimized flow channel design, the cooling capacity can be distributed more evenly, the temperature difference between different battery cells in the battery pack can be reduced, and the battery aging problem caused by uneven temperature can be reduced.

[0024] The two-stage cooling distribution module consists of a first-stage conical throttle valve and a second-stage microchannel heat transfer tube. The conical throttle valve, located on the inlet manifold, dynamically adjusts cooling distribution based on the coolant inlet pressure, ensuring that coolant flows to different battery sections as needed. The inner wall of the microchannel heat transfer tube is coated with a carbon nanotube coating, which offers excellent thermal conductivity, enhancing heat exchange. Quick-connect connectors provide a rigid connection to the battery cooling plate, ensuring system stability and tightness. This cascaded cooling distribution design enables precise cooling of different battery cells, significantly improving cooling efficiency and reducing battery damage caused by overcooling or overheating.

[0025] The vehicle-mounted coupled thermal management module uses a solenoid three-way valve to switch between the phase-change cooling circuit and the vehicle air conditioning circuit. A check valve is added to the refrigerant outlet pipe of the charging station, enabling a cold storage mechanism that utilizes off-peak electricity for pre-charging and cooling. This design pre-charges the system during off-peak periods, storing a certain amount of cold energy through phase-change cooling for rapid release during peak charging times, reducing the burden on the grid and improving charging efficiency.

[0026] The intelligent control module dynamically adjusts the coolant flow rate and circuit switching logic based on phase change material deformation data detected by battery surface temperature sensors, coolant flow meters, and resistance strain gauges. This intelligent control system accurately determines the battery's temperature distribution and cooling requirements based on real-time data, adjusting the cooling strategy in real time to ensure temperatures remain within a safe range. The system also implements a strategy to recover residual cooling energy after charging. By optimizing cooling energy utilization, it reduces unnecessary energy consumption and improves overall system efficiency.

[0027] Through the coordinated work of various modules, the heat generated during the battery charging process can be precisely controlled to avoid problems such as overheating and overcooling, thereby improving the safety and efficiency of battery charging, extending the battery life, and improving the overall performance and energy saving effects of the system.

[0028] In one possible implementation, in this embodiment, the rate of decrease in the height of the flow channel cross section of the gradient flow channel unit is dynamically adjusted based on real-time feedback of the refrigerant inlet pressure and outlet flow rate. This means that when the refrigerant flows into the flow channel, the system monitors the inlet pressure and outlet flow rate, and uses these data to adjust the shape and size of the flow channel to ensure that the flow rate at the end of the flow channel remains in a suitable range to avoid the situation where the flow rate is too low. Low flow rate may cause local solidification of the phase change material, thereby affecting the cooling effect and causing thermal runaway. Through this dynamic adjustment method, the flow rate is ensured to be above the critical flow rate, which avoids the solidification of the phase change material and thus ensures the stability and efficiency of the cooling system.

[0029] To optimize the balance between heat exchange efficiency and pressure drop, an experimental calibration method was used to determine the incremental rate of corrugated fin density. Specifically, a heat exchange efficiency model for the final section of the flow channel was established. This model accounts for factors such as the specific heat capacity of the refrigerant, the latent heat release rate of the phase change material, and the range of ambient temperature fluctuations. Changes in these factors directly affect the relationship between heat exchange efficiency and pressure drop. Based on this, prototype testing was conducted to collect heat exchange efficiency and pressure drop data for different corrugated fin configurations with different densities, further analyzing the trade-off between them.

[0030] After experimental calibration, the system was constrained to maintain a 10% drop in heat exchange efficiency and a 15% increase in pressure rise. This meant that during the design process, the goal was to maintain high heat exchange efficiency while minimizing pressure drop, ensuring the system's overall performance remained within the optimal range. Through this experimental verification and data fitting, the optimal range for the corrugated fin density increase rate was ultimately determined, enabling the system to balance heat exchange efficiency and flow resistance at varying flow rates, improving thermal management effectiveness.

[0031] Dynamically adjusting the height of the flow channel cross section ensures that the flow rate is always within the appropriate range, effectively preventing local solidification of the phase change material, thereby ensuring the stability and efficient cooling performance of the system under different working conditions. Secondly, through precise experimental calibration and optimization of the density increase rate, the relationship between heat exchange efficiency and fluid pressure drop is balanced, improving heat exchange performance while avoiding energy loss. These optimization measures enable the system to not only respond quickly to different working conditions, but also maintain efficient and stable performance during long-term operation, improving the overall thermal management effect, extending the battery life, and improving the safety and efficiency of the charging process.

[0032] In one possible implementation, in this embodiment, the surface tension coefficient and density of the composite phase change material in liquid state are first measured. The surface tension coefficient reflects the mutual attraction between the molecules of the material, while the density determines the mass-volume relationship of the material. Next, the basic pore size, that is, the initial size of the connected pores, is calculated by combining the acceleration of gravity. The calculation of the basic pore size is based on the capillary force theory. The capillary force can drive the liquid phase change material to flow in the honeycomb structure, and the flow rate is closely related to the size of the pore size. The basic pore size provides a preliminary reference value for subsequent pore size optimization.

[0033] Next, contact angle experiments are used to calibrate the wettability correction factor of the phase change material on the connecting plate. The wettability correction factor describes the material surface's affinity for the phase change liquid, specifically the extent to which the liquid spreads across the solid surface. The correction factor is negatively correlated with the wetting angle between the phase change material and the connecting plate, meaning that the stronger the wettability of the phase change material, the larger the correction factor. Contact angle experiments quantify the material's wettability and, in turn, correct the pore size calculations to ensure that the actual pore size better matches actual flow requirements.

[0034] The final connected pore diameter is generated by multiplying the base pore diameter by the correction factor. This ensures a more precise match between the capillary flow rate and the heat absorption rate of the coolant. A pore diameter that is too large or too small can result in an incompatible flow rate, thus affecting cooling efficiency. Therefore, precise calculation and correction ensure that the flow rate matches the heat exchange requirements, avoiding issues such as the phase change material failing to absorb heat in time due to too low a flow rate, or uneven cooling due to too high a flow rate.

[0035] By precisely calculating the interconnected pore diameters, the liquid phase-change material can flow more smoothly within the honeycomb structure, avoiding localized cooling failures caused by insufficient capillary forces. Furthermore, the optimized pore size design matches the heat absorption rate of the phase-change material, improving the thermal management performance of the entire on-board charging device. Ultimately, this meticulous pore size calculation and optimization not only improves charging efficiency but also extends battery life, enhancing system safety and reliability.

[0036] In one possible implementation, the peak heat generation power of the battery pack is first calculated. This is accomplished by multiplying the battery's charge / discharge rate by its internal resistance. The charge / discharge rate reflects the rate at which the battery discharges or charges, while the internal resistance determines the degree of heat generated during the charge / discharge process. These two parameters can be used to determine the heat release rate of the battery pack at maximum power, providing basic data for cooling system design.

[0037] Second, the model needs to determine the latent heat release rate of the PCM. This rate is calculated by multiplying the solidification ratio by the total latent heat value of the PCM in real time. As the PCM undergoes a phase change (e.g., from liquid to solid), a certain amount of latent heat is released or absorbed. The solidification ratio describes the degree to which the PCM transforms to a solid state within a specific timeframe, while the total latent heat value reflects the amount of heat released during complete solidification. Therefore, by monitoring the solidification ratio and latent heat value in real time, the PCM heat release rate can be accurately calculated, thereby optimizing cooling.

[0038] The ambient temperature compensation coefficient is derived by fitting the temperature-heat dissipation efficiency curve based on historical data from the vehicle's temperature control system. As the ambient temperature changes, the heat dissipation efficiency also varies. Therefore, the temperature compensation coefficient adjusts the system's cooling requirements based on the current in-vehicle temperature and environmental conditions. For example, when the external temperature is high, the temperature control system may require higher cooling efficiency. The temperature compensation coefficient helps adjust the system's heat dissipation capacity to suit different operating environments.

[0039] Using the above input parameters, the cooling demand allocation model calculates the required number of microchannels per unit time. This cooling demand allocation takes into account the combined effects of battery heat generation, heat release from the phase change material, and environmental factors. By optimizing the number of microchannels, the system improves heat exchange efficiency while maintaining a low pressure drop, ensuring that the battery pack remains within a safe and efficient temperature range during charging.

[0040] By accurately calculating the required number of microchannels based on the battery pack's heat generation power, the latent heat release rate of the phase change material, and changes in ambient temperature, the system's thermal management capabilities can be significantly improved. Secondly, by adjusting the cooling system in real time to adapt to varying ambient temperatures and charging states, the cooling effect is optimized and energy efficiency is improved. Furthermore, precise allocation of cooling demand avoids unnecessary energy waste, thereby improving the overall system performance and battery life. These innovative measures enable the phase change cold storage on-board charging device to provide higher cooling efficiency and better temperature control in practical applications, ensuring the safety and reliability of the vehicle during charging.

[0041] In one possible implementation, when the difference between the maximum and minimum temperatures of the battery pack exceeds a preset temperature difference threshold, the intelligent control module activates the variable flow pump to adjust the flow of the coolant. The temperature difference threshold can be set according to the specific application scenario to ensure the temperature uniformity of the battery pack. When the temperature difference is too large, it means that part of the battery pack is overheating, and the flow rate needs to be adjusted to improve the cooling efficiency. The adjustment range is dynamically generated based on the temperature difference suppression efficiency mapping table trained with historical charging data. This mapping table optimizes the temperature difference suppression strategy by analyzing historical charging data, making the flow regulation more accurate and efficient.

[0042] When the maximum temperature of the battery pack exceeds the activation threshold of phase change cooling, the intelligent control module will switch to the phase change cooling circuit and increase the flow rate to improve cooling efficiency. The dynamic adjustment of the activation threshold is one of the core of this control logic. Specifically, the activation threshold is dynamically corrected according to the real-time solidification ratio of the phase change material. When the solidification ratio of the phase change material is low, it means that the phase change material has not yet completely released heat. At this time, strong cooling needs to be started earlier to avoid excessive battery temperature affecting safety. By monitoring the solidification ratio in real time, the system can start the strong cooling strategy in advance to ensure that the battery pack is always within a safe temperature range.

[0043] After charging is complete, the intelligent control module controls the duration and volume of cooling air drawn by the onboard air conditioning fan based on the residual cooling capacity of the phase change module and the target passenger compartment temperature drop. The phase change module accumulates a certain amount of cooling capacity during charging. After charging, if the interior temperature is high, the system uses this residual cooling capacity to lower the interior temperature to the target value through the air conditioning fan. By precisely controlling the duration and volume of cooling air drawn by the fan, the system can effectively regulate the interior temperature while avoiding energy waste.

[0044] This intelligent control logic enables precise temperature control and cooling management, ensuring that the temperature of the battery pack remains within a safe range during the charging process, thereby improving charging efficiency and battery life. When the temperature difference of the battery pack is too large, the system adjusts the coolant flow rate to balance the temperature distribution of the battery, effectively preventing local overheating. The switching and flow increase of the phase change cooling circuit can respond quickly when the battery temperature exceeds the preset threshold, ensuring stable temperature control during the charging process. The air conditioning temperature adjustment after charging is completed not only improves the comfort in the car, but also optimizes the efficiency of the cooling capacity and avoids unnecessary energy waste. Overall, this control logic can improve the overall performance of the on-board charging system and battery safety, while providing a more comfortable in-car environment for passengers.

[0045] In one possible implementation, historical charging data is first analyzed to establish a mapping between coolant flow rate and temperature differential suppression efficiency. This process uses a neural network model for training to accurately predict the cooling system's effectiveness in suppressing battery pack temperature differentials under different flow conditions. The training input variables include the battery pack temperature distribution variance, ambient humidity, and charging current rate. The battery pack temperature distribution variance describes the differences between various temperature points within the battery pack. Ambient humidity affects the variation in cooling effectiveness, while the charging current rate is directly related to the heat generation rate of the battery pack.

[0046] During charging, the system collects the battery pack's temperature distribution variance in real time and acquires ambient humidity data through onboard environmental sensors. These sensors continuously monitor the battery pack's temperature and provide precise humidity readings for the vehicle's interior. A greater temperature distribution variance indicates a more uneven heat distribution in the battery pack, requiring appropriate adjustments to the cooling system.

[0047] Real-time data collected, such as the battery pack temperature distribution variance, ambient humidity, and charging current rate, is fed into a trained neural network model. This neural network analyzes the relationship between the input variables and the flow regulation effect, outputting the optimal flow regulation ratio. This allows the system to dynamically calculate the most appropriate coolant flow rate based on the current state, effectively reducing temperature differences within the battery pack and ensuring battery safety and charging efficiency.

[0048] The output regulation ratio also includes the direction of regulation. Specifically, the direction of flow regulation is inversely proportional to the positive or negative value of the temperature distribution variance. A positive temperature distribution variance indicates a large temperature difference within the battery pack, requiring the system to increase flow to improve cooling and balance the battery pack temperature. A negative temperature distribution variance indicates a relatively uniform battery pack temperature, requiring the system to reduce flow to conserve energy and avoid overcooling.

[0049] By dynamically adjusting the coolant flow rate, the system can respond to changes in battery pack temperature in real time, effectively suppressing excessive temperature differences, thereby improving charging efficiency and extending battery life. Furthermore, by utilizing a neural network model for training and real-time flow adjustment, the system can precisely control the cooling effect based on real-time data on ambient humidity, battery temperature, and charging current, avoiding excessive or insufficient cooling, thereby improving energy efficiency and charging safety. Overall, this technology enhances the intelligence level of phase-change cold storage on-board charging devices, making temperature management more precise and efficient.

[0050] In one possible implementation, the composite phase-change material in this embodiment utilizes a combination of paraffin wax, expanded graphite, and epoxy resin. The paraffin wax provides phase-change energy storage, the expanded graphite enhances thermal conductivity, and the epoxy resin serves as a matrix material to ensure structural stability. When optimizing the formulation, the goal is to maximize the latent heat of the composite (i.e., its ability to absorb and release heat during phase change) while ensuring that the thermal conductivity meets certain standards for efficient heat transfer.

[0051] To determine the optimal ratio, a three-factor, five-level orthogonal experimental design was used. The experimental factors included the ratios of paraffin wax, expanded graphite, and epoxy resin, with each factor set at five different levels to cover a wide range of possible combinations. The advantage of an orthogonal design is that it can obtain valid results with a small number of experiments, reducing experimental costs and improving efficiency.

[0052] After determining different ratio combinations, each ratio is tested for performance, mainly testing three parameters: Latent heat value: Test the latent heat value of the material at each ratio to evaluate the heat stored and released during the phase change process.

[0053] Thermal Conductivity: This measures a material's ability to conduct heat, assessing how efficiently it transfers heat during charging. The addition of expanded graphite can help improve thermal conductivity.

[0054] Viscosity: Viscosity is a key factor affecting material flowability and heat transfer efficiency during phase change. A rotational viscometer is used to continuously measure viscosity within the phase change temperature range to ensure that the material maintains proper flowability during operation.

[0055] After all tests were completed, a weighted scoring method was used to comprehensively evaluate the performance of each ratio. The weight of latent heat was set to ≥70%, and the weight of thermal conductivity was set to ≤30%. This is because latent heat plays a primary role in the performance of phase change materials, while thermal conductivity is a secondary factor. This weighted scoring method can quantitatively score each ratio and determine the ratio with the best overall performance.

[0056] Through this optimization process, the performance of the composite phase change material has been significantly improved. First, maximizing the latent heat value ensures that the material effectively absorbs and releases heat during the charging process, enhancing the system's heat storage capacity and improving cooling efficiency. Secondly, the optimization of the thermal conductivity coefficient ensures the thermal conductivity of the material, allowing heat to be quickly transferred from the battery pack to the cooling system to avoid local overheating. Proper adjustment of the viscosity ensures that the material has good fluidity during the phase change process, avoiding the impact of excessive flow resistance on the heat dissipation effect. Overall, this optimization scheme enables the composite phase change material to maintain good thermal conductivity and fluidity while meeting high latent heat energy storage by precisely adjusting the ratio of paraffin wax, expanded graphite and epoxy resin, thereby improving the thermal management performance and system reliability of the phase change cold storage on-board charging device.

[0057] In one possible implementation, the quick-connect connector in an on-board charging device needs to maintain a good seal under vibration. To simulate the vibrations experienced in actual vehicle use, the connector is first tested on a vibration table. The vibration table's frequency range is set to 5 to 200 Hz, with an acceleration of 3g. This frequency range covers the common vibration spectrum in a vehicle environment, such as vibrations caused by engine operation and road unevenness. This test accurately simulates the vibration conditions that the connector may encounter during actual use, ensuring its performance in this environment.

[0058] The joint's sealing performance is tested in a simulated vibration environment. During the test, the joint is subjected to the vibration frequency and acceleration generated by the shaker to simulate various vibration conditions that may occur during vehicle operation. The core of the test is to determine whether the joint can maintain its original sealing performance under these vibration conditions.

[0059] During the sealing performance test, the insertion and removal force is gradually increased until the connector leakage rate exceeds the set sealing threshold. This process aims to determine the maximum insertion and removal force of the connector during continuous insertion and removal operations. Insertion and removal force refers to the amount of force required to connect the connector. Excessive insertion and removal force can cause the connector seal to fail or even damage, so a critical value needs to be found.

[0060] As the insertion and removal force gradually increases, when the joint's leakage rate exceeds the set sealing threshold, the joint's sealing performance is considered to have reached a critical point. This insertion and removal force value is the critical leakage insertion and removal force, an important indicator of whether the joint's sealing performance can be maintained under external vibration.

[0061] To ensure the connector design meets long-term use requirements, the upper limit of the connector insertion and removal force is set at 90% of the critical leakage insertion and removal force. This setting ensures that the connector seal will not fail or be damaged due to excessive insertion and removal force during normal use, thereby improving system reliability and safety. This setting prevents frequent failures or water or air leaks caused by excessive insertion and removal force in actual use.

[0062] By simulating the vehicle-mounted vibration spectrum for testing, the sealing performance of the connector in the vehicle environment can be ensured. Even if vibration occurs during driving, the connector can still maintain a stable sealing state, avoiding leakage problems caused by vibration. Setting the upper limit of the connector design plug-in and pull-out force to 90% of the leakage critical plug-in and pull-out force can effectively prevent sealing failure caused by excessive plug-in and pull-out, and extend the service life of the device. Overall, this technology optimizes the plug-in and pull-out performance of the on-board charging device, enhances its adaptability in complex dynamic environments, and enables the device to maintain good sealing and performance stability during long-term use.

[0063] In one possible implementation, one of the activation conditions for valley-hour pre-cooling is when the real-time grid electricity price is below a preset threshold. Electricity prices fluctuate in the electricity market, typically at night or during off-peak hours, when grid prices are lower. Charging the onboard cold storage device is therefore more economical. The charging station communication module can access data from the electricity market trading platform in real time and, by connecting to the electricity market system, determine whether the current grid electricity price is below a preset threshold. If the price is low, the system triggers the pre-cooling mechanism, using the valley-hour electricity price to charge the cold storage device, thereby reducing charging costs and maximizing resource utilization.

[0064] Another activation condition is that the remaining cold storage capacity of the phase change material is lower than the safety margin threshold. In order to ensure that the on-board charging system can still effectively cool during long-term use, the system needs to monitor the remaining cold storage capacity of the phase change material in real time. When the cold storage capacity of the phase change material is insufficient to meet the needs of the next charging cycle, the cold storage device will be activated. Using the deformation sensor data and calculating with the solidification ratio fitting model, the remaining cold storage capacity of the phase change material can be evaluated in real time. If the remaining capacity is lower than the set safety margin threshold, it means that the storage capacity of the cold storage device is insufficient, and the system will start the pre-charging mechanism to supplement the cold storage capacity.

[0065] The pre-cooling mechanism also relies on whether the next scheduled charging interval is greater than the effective cold storage duration. The onboard navigation system can determine the next charging interval based on the predicted time difference between travel nodes. If the planned charging interval is greater than the effective cold storage duration (i.e., the cooling capacity of the cold storage device will gradually decrease during this interval), the system will activate the pre-cooling function. This way, the onboard charger replenishes cooling capacity using off-peak electricity prices before charging, ensuring that good cooling is maintained during the charging process.

[0066] The core advantage of this activation condition mechanism lies in intelligently managing the cold storage capacity of the on-board charger through rational scheduling and price fluctuations in the power market. First, charging by taking advantage of off-peak electricity prices not only reduces charging costs but also improves energy efficiency. Second, by real-time monitoring of cold storage capacity and predicting charging periods, the cold storage device maintains optimal cooling during the charging process, avoiding reduced charging efficiency or excessive temperatures that could affect charging safety due to insufficient cold storage. Finally, combined with the predictive capabilities of the on-board navigation system, it accurately determines charging time and cooling requirements, rationally scheduling charging and cold storage operations, and enhancing the intelligence and adaptability of the on-board charger. This comprehensive mechanism improves the efficiency, stability, and energy efficiency of the charging system.

[0067] In one possible implementation, during actual use, there is a certain correlation between the battery pack's temperature rise rate and the phase-change material's cooling coefficient. By statistically analyzing the battery pack's temperature rise rate during historical charging cycles and combining it with the phase-change material's cooling coefficient during different charging cycles, the system can determine the relationship between the two. This process helps the system accurately assess how the phase-change material's cooling effect affects the battery pack's temperature rise under different charging loads, providing important basic data for subsequent dynamic calculations.

[0068] The battery's health status directly affects its temperature rise rate. Battery health status changes over time due to factors such as battery aging, increased charge cycles, and wear and tear. Therefore, to improve calculation accuracy, the system monitors the battery's health status in real time and adjusts the predicted temperature rise rate based on the current battery status. This correction ensures that the temperature rise prediction more closely matches the actual battery condition, avoiding inadequate or excessive temperature control due to changes in battery health status.

[0069] To ensure safe temperature control of the battery pack during the next charging cycle, the system reversely calculates the minimum required cooling capacity based on the corrected temperature rise rate prediction. This process takes into account multiple factors, including charging current, charging time, and ambient temperature, to calculate the minimum cooling capacity required to keep the battery temperature within a safe range under specific conditions.

[0070] Ultimately, the minimum required cold storage capacity was increased by 120% to establish a safety margin threshold. This 120% margin ensures sufficient cooling capacity to prevent battery overheating and other potential safety issues during charging, such as sudden increases in battery load or drastic changes in ambient temperature. The purpose of establishing a safety margin threshold is to provide additional safety measures for the on-board charger to adapt to varying operating environments and battery conditions.

[0071] By comprehensively considering historical data, battery health status, and the cooling capacity of phase change materials, the system can dynamically adjust the safety margin threshold to ensure that the on-board charging device can provide sufficient cooling capacity under various charging conditions, avoiding safety hazards caused by battery overheating or insufficient cooling. In addition, this process can achieve adaptive adjustment for different charging cycles, optimize the configuration of cooling capacity in real time according to the health status and charging load of different batteries, and improve the overall performance and safety of the on-board charging device. In short, by dynamically calculating the safety margin threshold, it is possible to improve charging efficiency and battery life while ensuring safe temperature control. Figure 3 It can be seen that the present invention has a lower temperature and smoother control during fast charging.

[0072] The present invention encompasses any alternatives, modifications, equivalents, and solutions that fall within the spirit and scope of the present invention. To provide a thorough understanding of the present invention, specific details are described in detail below in connection with the preferred embodiments of the present invention, but those skilled in the art will be able to fully understand the present invention without these detailed descriptions. Furthermore, to avoid unnecessary confusion regarding the essence of the present invention, well-known methods, processes, procedures, components, and circuits have not been described in detail.

[0073] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A phase change cold storage vehicle charging device, characterized in that: Includes the following modules that work together: The composite phase-change cold storage module includes a multi-cavity honeycomb structure, which is formed by welding corrugated plates and connecting plates to form a phase-change material storage space, and the interior is filled with composite phase-change material. The openings in the connecting plates connect adjacent honeycomb cavities, and the capillary force drives the liquid phase-change material to flow. The gradient flow channel unit is integrated into the composite phase change cold storage module. The refrigerant flow channel adopts a variable cross-section multi-return design. The cross-sectional height of the flow channel decreases along the flow direction, and the density of the corrugated plate fin increases along the flow direction. A two-stage cooling distribution module includes a first-stage conical throttle valve and a second-stage microchannel heat transfer tube. The conical throttle valve is installed on the inlet manifold and dynamically adjusts the branch flow rate based on the refrigerant inlet pressure. The inner wall of the microchannel heat transfer tube is coated with a carbon nanotube coating and is hard-connected to the battery cooling plate via a quick-connect connector. The vehicle-mounted coupled thermal management module switches the phase-change cooling circuit and the vehicle air conditioning circuit via a solenoid three-way valve. A check valve is added to the refrigerant outlet pipe of the charging pile to implement a cold storage mechanism that utilizes valley electricity for pre-charging. The intelligent control module dynamically adjusts the coolant flow rate and circuit switching logic based on the phase change material deformation data detected by the battery surface temperature sensor, coolant flow meter and resistance strain gauge, and simultaneously implements the residual cold recovery strategy after charging is completed.

2. A phase change cold storage vehicle-mounted charging device according to claim 1, characterized in that: The gradient channel unit's channel cross-sectional height decrease rate is dynamically adjusted based on feedback from the coolant inlet pressure and outlet flow rate to ensure that the terminal flow rate is no less than the critical flow rate for preventing local solidification of the phase change material. The corrugated plate fin density increase rate is determined by experimentally calibrating the balance between the heat exchange efficiency and pressure drop at the end of the channel, specifically including: Establish a heat exchange efficiency model for the final section of the flow channel. Input parameters include the specific heat capacity of the refrigerant, the latent heat release rate of the phase change material, and the ambient temperature fluctuation range. Through prototype testing of variable fin density, heat exchange efficiency and pressure drop data at different densities were collected; With the constraints of heat exchange efficiency decrease rate ≤ 10% and pressure rise increase rate ≤ 15%, the optimal range of fin density increase rate was fitted.

3. A phase change cold storage vehicle-mounted charging device according to claim 2, characterized in that: The connected pore diameter of the multi-cavity honeycomb structure is determined by capillary force model calculation, specifically including: Measure the surface tension coefficient and density of the composite phase change material in liquid state, and calculate the basic pore diameter in combination with the gravitational acceleration; The material wettability correction coefficient is calibrated through contact angle experiments. The correction coefficient is negatively correlated with the wetting angle of the phase change material to the connected plate. The final connected pore diameter is generated based on the product of the basic pore diameter and the correction coefficient to ensure that the flow rate driven by the capillary force matches the heat absorption rate of the coolant.

4. The phase change cold storage vehicle-mounted charging device according to claim 1, characterized in that: The number of microchannels in the secondary microchannel heat transfer tube is determined based on a unit time cooling demand distribution model, and the model input parameters include: The peak heating power of the battery pack is calculated by multiplying the battery charge and discharge rate by the internal resistance; The latent heat release rate of the phase change material is obtained by multiplying the solidification ratio by the total latent heat value in real time; The ambient temperature compensation coefficient is obtained by mapping the temperature-heat dissipation efficiency curve based on the historical data of the vehicle temperature control system.

5. The phase change cold storage vehicle-mounted charging device according to claim 1, characterized in that: The intelligent control module executes the following control logic: When the difference between the maximum and minimum temperatures of the battery pack exceeds a preset temperature difference threshold, the variable flow pump is activated to adjust the coolant flow. The adjustment range is dynamically generated based on the temperature difference suppression efficiency mapping table trained with historical charging data. When the maximum battery temperature exceeds the phase change cooling activation threshold, the system switches to the phase change cooling circuit and increases the flow rate. The activation threshold is dynamically adjusted according to the real-time solidification ratio of the phase change material: the lower the solidification ratio, the lower the activation threshold is to start strong cooling earlier. After charging is completed, the duration and air volume of the vehicle air-conditioning fan extracting cold air are controlled based on the residual cooling capacity of the phase change module and the target temperature drop value of the passenger compartment.

6. A phase change cold storage vehicle-mounted charging device according to claim 5, characterized in that: The adjustment amplitude of the variable flow pump is dynamically generated by the following process: A mapping table between coolant flow rate and temperature difference suppression efficiency was constructed, and a neural network model was trained on historical charging data. Input variables included battery pack temperature distribution variance, ambient humidity, and charging current rate. Collect battery pack temperature distribution variance in real time and obtain humidity data through on-board environmental sensors; The input variables are imported into the trained neural network model to output the optimal flow regulation ratio. The regulation direction is in the same direction as the positive and negative values ​​of the temperature distribution variance.

7. The phase change cold storage vehicle-mounted charging device according to claim 1, characterized in that: The composite phase change material is a paraffin-based composite material, and its component ratio is determined by orthogonal test optimization: Taking the maximization of latent heat value and the achievement of thermal conductivity as the optimization goals, a three-factor five-level orthogonal table of paraffin wax, expanded graphite, and epoxy resin was set up; The latent heat value, thermal conductivity and viscosity under different ratios were tested, and the viscosity was continuously measured within the phase change temperature range using a rotational viscometer; The optimal ratio of comprehensive performance is calculated by weighted scoring method, with the latent heat value weight ≥ 70% and the thermal conductivity coefficient weight ≤ 30%.

8. The phase change cold storage vehicle-mounted charging device according to claim 1, characterized in that: The critical value of the insertion and extraction force of the quick-connect connector is determined by vibration adaptability testing: Simulate vehicle vibration spectrum and test joint sealing performance on a vibration table with a frequency of 5–200 Hz and an acceleration of 3g; Gradually increase the insertion and extraction force until the leakage rate exceeds the sealing threshold, and record the critical insertion and extraction force for leakage; Set 90% of the critical insertion and extraction force as the upper limit of the connector design insertion and extraction force.

9. The phase change cold storage vehicle-mounted charging device according to claim 1, characterized in that: The activation conditions of the cold storage mechanism using valley electricity pre-charging include: When the real-time electricity price of the power grid is lower than the preset electricity price threshold, the data of the power market trading platform is obtained through the charging pile communication module; The remaining cold storage capacity of the phase change material is lower than the safety margin threshold, which is calculated by fitting the deformation sensor data with the solidification ratio model; The next planned charging time interval is greater than the effective duration of cold storage, which is determined by the time difference between the travel nodes predicted by the on-board navigation system.

10. The phase change cold storage vehicle-mounted charging device according to claim 9, characterized in that: The safety margin threshold is dynamically calculated through the following process: Calculate the correlation between the average temperature rise rate of the battery pack and the cooling coefficient of the phase change material during the historical charging cycle; Correct the predicted temperature rise rate based on the current battery health status; With the constraint of maintaining safe temperature control for the next charging cycle, the required minimum cold storage capacity is reversed, and 120% of it is set as the safety margin threshold.

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