A phase change cold storage type vehicle-mounted charging device

Abstract

The present application relates to electric vehicle charging technology field, especially to a kind of phase change cold accumulation type vehicle-mounted charging device, including the following modules of coordinated work: composite phase change cold accumulation module, including multi-cavity honeycomb structure;Gradient flow channel unit is integrated in composite phase change cold accumulation module interior, and cold accumulator flow channel adopts variable cross section multi-return design, flow channel cross section height decreases along flow direction, and corrugated sheet fin density increases along flow direction;Two-stage cold distribution module, including primary conical throttle valve and secondary microchannel heat pipe;Vehicle-mounted coupling thermal management module, through electromagnetic three-way valve switching phase change cooling circuit and vehicle-mounted air conditioning circuit, and in the cold accumulator outlet pipe of charging pile, additional check valve is added, realizes the cold accumulation mechanism using valley electricity pre-charging;Intelligent control module.By combining phase change material, gradient flow channel design, intelligent control algorithm and two-stage cold distribution strategy, the device effectively reduces the temperature rise in battery charging process, ensures charging safety and optimizes energy utilization.

Description

TECHNICAL FIELD

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

[0002] With the popularization of electric vehicle direct current fast charging technology (charging rate ≥ 4C), power batteries face severe thermal management challenges during fast charging. The existing thermal management system has the following technical defects to be solved:

[0003] 1. Fast charging temperature rise out of control problem;

[0004] During high-rate charging, the polarization of lithium ions in the electrode solid phase diffusion rate lags behind, resulting in increased polarization, and the instantaneous heat power of the battery can reach 5-8 times that of conventional charging. The traditional liquid cooling system cannot timely suppress the local temperature rise of the battery cell due to the delay of thermal response (> 30 seconds), resulting in a hotspot temperature exceeding 60℃. Experiments show that if the temperature peak value of single fast charging is > 45℃, the battery capacity attenuation rate will increase by more than 40%; if > 60℃, the SEI film decomposition reaction will accelerate, which may cause thermal runaway.

[0005] 2. Battery pack temperature gradient imbalance problem;

[0006] Due to the difference in position (such as edge and center cells), manufacturing process fluctuation (such as electrode coating thickness error) and uneven contact thermal resistance, significant temperature difference is generated in each single cell in the battery pack. The existing air cooling / liquid cooling system is difficult to achieve uniform heat dissipation:

[0007] The liquid cooling plate usually adopts a serpentine flow channel design, resulting in a temperature difference > 15℃ between the inlet and outlet areas of the cooling liquid;

[0008] When the temperature difference between the cells is > 10℃, the internal resistance difference is expanded, causing circulating current effect, accelerating the overcharge aging of low internal resistance cells, capacity loss of high internal resistance cells, and overall life shortening by 30%.

[0009] Therefore, there is an urgent need for a phase change cold storage type vehicle-mounted charging device to solve the above problems. SUMMARY

[0010] Based on the above purpose, the present application provides a phase change cold storage type vehicle-mounted charging device, which comprises the following modules working cooperatively:

[0011] The composite phase change cold storage module comprises a multi-cavity honeycomb structure, and the multi-cavity honeycomb structure is formed by welding a corrugated plate and a connecting plate to form a phase change material storage space, which is filled with a composite phase change material; the connecting plate is perforated to connect adjacent honeycomb cavities, and the liquid phase change material is driven to flow by capillary force;

[0012] The gradient flow channel unit is integrated in the composite phase change cold storage module, the cold carrier flow channel adopts a variable cross-section multi-return design, the flow channel cross-section height decreases along the flow direction, and the corrugated plate fin density increases along the flow direction;

[0013] The two-stage cold distribution module includes a one-stage conical throttle valve and a two-stage micro-channel heat transfer pipe, the conical throttle valve is arranged in the inlet header, and the branch flow is dynamically adjusted according to the inlet pressure of the cold carrier; the inner wall of the micro-channel heat transfer pipe is coated with a carbon nanotube coating, and is hard connected with the battery cooling plate through a quick connection joint;

[0014] The vehicle-mounted coupled thermal management module switches the phase change cooling circuit and the vehicle-mounted air conditioning circuit through an electromagnetic three-way valve, and adds a check valve at the outlet pipe of the cold carrier of the charging pile, so that the cold storage mechanism using valley electricity pre-charging is realized;

[0015] The intelligent control module dynamically adjusts the cold carrier flow and the switching logic of the circuit based on the battery surface temperature sensor, the cold carrier flow meter and the deformation data of the phase change material detected by the resistance strain gauge, and simultaneously executes the residual cold recovery strategy after charging is completed.

[0016] Preferably, the flow channel cross-section height decreasing rate of the gradient flow channel unit is dynamically adjusted according to the feedback values of the inlet pressure and the outlet flow rate of the cold carrier, so as 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 fin density increasing rate of the corrugated plate is determined by experimentally calibrating the balance relationship between the heat exchange efficiency and the pressure drop of the flow channel tail section, and specifically includes:

[0017] A heat exchange efficiency model of the flow channel tail section is established, and the input parameters include the specific heat capacity of the cold carrier, the latent heat release rate of the phase change material and the environmental temperature fluctuation range;

[0018] Through the prototype test of the variable fin density, the heat exchange efficiency and pressure drop data under different densities are collected;

[0019] Taking the heat exchange efficiency decreasing rate ≤10% and the pressure rise increasing amplitude ≤15% as constraint conditions, the optimal interval of the fin density increasing rate is fitted.

[0020] Preferably, the communication aperture of the multi-cavity honeycomb structure is determined by a capillary force model, and specifically includes:

[0021] The surface tension coefficient and the density of the composite phase change material in the liquid state are measured, and the basic aperture is calculated in combination with the gravitational acceleration;

[0022] The material wettability correction coefficient is calibrated through a contact angle experiment, and the correction coefficient is negatively correlated with the wetting angle of the phase change material to the connecting plate;

[0023] Based on the product of the basic aperture and the correction coefficient, the final communication aperture is generated, so as to ensure that the flow rate driven by the capillary force matches the heat absorption rate of the cold carrier.

[0024] Preferably, the number of microchannels of the secondary microchannel heat pipe is determined based on a unit time cold demand distribution model, and the model input parameters include:

[0025] The battery pack peak heat power is calculated by the product of the battery charge-discharge rate and the internal resistance;

[0026] The latent heat release rate of the phase change material is obtained by the real-time product of the solidification ratio and the total latent heat value;

[0027] The ambient temperature compensation coefficient is obtained from the temperature-heat dissipation efficiency curve mapped according to the historical data of the vehicle temperature control system.

[0028] Preferably, the intelligent control module executes the following control logic:

[0029] When the difference between the highest temperature and the lowest temperature of the battery pack exceeds the preset temperature difference threshold, the variable flow pump is started to adjust the load refrigerant flow, and the adjustment range is dynamically generated based on the temperature difference suppression efficiency mapping table trained by the historical charging data;

[0030] When the highest temperature of the battery exceeds the phase change cooling activation threshold, switch to the phase change cooling circuit and increase the flow, and the activation threshold is dynamically corrected according to the real-time solidification ratio of the phase change material: the lower the solidification ratio, the lower the activation threshold to start strong cooling in advance;

[0031] After charging, based on the residual cold of the phase change module and the target temperature drop value of the passenger compartment, control the time length and air volume of the vehicle air conditioner fan to extract cold air.

[0032] Preferably, the adjustment range of the variable flow pump is dynamically generated by the following process:

[0033] A load refrigerant flow-temperature difference suppression efficiency mapping table is constructed, and the historical charging data is trained based on a neural network model, and the input variables include the temperature distribution variance of the battery pack, the ambient humidity and the charging current rate;

[0034] The temperature distribution variance of the battery pack is collected in real time, and the humidity data is obtained through the vehicle-mounted environmental sensor;

[0035] The input variables are imported into the trained neural network model, and the optimal flow adjustment ratio is output, and the adjustment direction and the positive and negative values of the temperature distribution variance are in the same direction.

[0036] Preferably, the composite phase change material is a paraffin-based composite material, and the component allocation ratio is determined by orthogonal test optimization:

[0037] The three-factor five-level orthogonal table of paraffin, expanded graphite and epoxy resin is set to maximize the latent heat value and meet the optimization target of the thermal conductivity coefficient;

[0038] Test latent heat value, thermal conductivity and viscosity under different proportions, wherein the viscosity is continuously measured by a rotary viscometer in the phase change temperature range;

[0039] Calculate the optimal proportion of comprehensive performance by weighted scoring method, latent heat value weight ≥ 70%, thermal conductivity weight ≤ 30%.

[0040] Preferably, the plug-in force critical value of the quick connection joint is determined by vibration suitability test:

[0041] Simulate the vehicle-mounted vibration spectrum, test the sealing performance of the joint on a vibration table with a frequency of 5-200 Hz and an acceleration of 3g;

[0042] Increase the plug-in force step by step until the leakage rate exceeds the sealing threshold, and record the leakage critical plug-in force;

[0043] Set 90% of the critical plug-in force as the upper limit of the plug-in force designed for the joint.

[0044] Preferably, the activation condition of the cold storage mechanism using valley electricity pre-charging includes:

[0045] The real-time electricity price of the power grid is lower than the preset electricity price threshold, and the power market transaction platform data is obtained through the charging pile communication module;

[0046] The remaining cold storage capacity of the phase change material is lower than the safety margin threshold, which is calculated through the deformation sensor data and the solidification ratio fitting model;

[0047] The next planned charging time interval is greater than the cold storage effective duration, which is determined by the travel node time difference predicted by the vehicle-mounted navigation system.

[0048] Preferably, the safety margin threshold is dynamically calculated by the following process:

[0049] Statistically correlate the average temperature rise rate of the battery pack and the cold consumption coefficient of the phase change material in the historical charging period;

[0050] Correct the temperature rise rate prediction value according to the current battery health state;

[0051] Constrain the minimum cold storage capacity required to maintain the safety temperature control of the next charging cycle, and set 120% of it as the safety margin threshold.

[0052] The beneficial effects of the present application are:

[0053] 1、The application introduces a composite phase change cold storage module and an intelligent control module, and uses a phase change material to absorb a large amount of charging heat during the charging process, thereby avoiding the defects that the traditional liquid cooling system cannot respond in time. In particular, through the instant switching and flow regulation of the phase change cooling circuit, the local temperature rise of the battery pack can be quickly inhibited, the hotspot temperature can be prevented from exceeding 60℃, the battery capacity attenuation rate can be effectively slowed down, and the problem of thermal runaway caused by excessively high temperature can be avoided, thereby improving the safety and service life of the battery.

[0054] 2、Through the gradient flow channel unit design of the application, the cooling agent flow channel with variable cross-section and multiple return strokes is used to enable the flow rate and flow path of the cooling liquid to be adaptively adjusted according to the heat demand of the battery pack. In particular, the decreasing design of the flow channel cross-section and the increasing density of the corrugated plate fins can ensure that the temperature difference is minimized and uniform heat dissipation is achieved. In addition, the secondary cold quantity distribution module ensures the temperature balance of each single cell of the battery through accurate cold quantity distribution, avoids the overcharge and undercharge problems caused by the internal resistance difference between the cells, and significantly prolongs the overall service life of the battery.

[0055] 3、The application uses an intelligent control module to dynamically adjust the cooling agent flow and circuit switching based on real-time battery surface temperature sensors, cooling agent flow meters and other data. The intelligent control module accurately adjusts the cooling strategy according to the battery pack temperature distribution, cooling agent flow and battery heating condition, ensures rapid response to temperature rise during rapid charging, greatly improves the response speed and adjustment accuracy of the system, and avoids the occurrence of excessively high temperature.

[0056] 4、The phase change cooling system in the application realizes the pre-storage of cold quantity through the cold storage mechanism of valley power pre-charging and cooling, and combines the check valve and electromagnetic three-way valve switching technology of the vehicle-mounted coupled thermal management module to ensure that the cooling circuit can be flexibly switched according to the battery temperature change during the charging process, thereby not only improving the cooling efficiency but also effectively reducing the thermal load of the air conditioning system on the battery and reducing the energy consumption. This efficient cold quantity distribution and storage mechanism can ensure battery temperature control while achieving energy-saving operation of the system. BRIEF DESCRIPTION OF DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0058] Fig. 1 It is a schematic diagram of the module connection of the device of the application;

[0059] Fig. 2 It is a step flow chart of calculating the communication aperture of the multi-cavity honeycomb structure in the device of the application;

[0060] Fig. 3 The fast charging temperature rise comparison curve of the application. DETAILED DESCRIPTION

[0061] The application will be described in detail below with reference to the drawings and specific embodiments. It should be noted here that in order to make the embodiments more detailed, the following embodiments are the best, preferred embodiments, and other alternative ways can also be implemented by those skilled in the art for some known technologies; and the drawings are only used to describe the embodiments more specifically, and are not intended to specifically limit the application.

[0062] Please refer to Figs. 1-3 The application provides a phase change cold storage type vehicle-mounted 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 composite phase change material is filled in the spaces. The composite phase change material can absorb the heat generated during battery charging and effectively control the temperature through the phase change process. The connecting plate openings make the adjacent honeycomb cavities communicate, and the capillary force is used to push the liquid phase change material to flow, thereby enhancing the heat exchange efficiency. Through this design, the battery local temperature rise can be quickly reacted and inhibited, and the battery attenuation or thermal runaway caused by high temperature can be avoided. The application of the phase change material effectively improves the response speed of the thermal management, ensures that the temperature does not rise rapidly, and guarantees the charging safety of the battery.

[0063] The gradient flow channel unit is integrated in the composite phase change cold storage module, and the carrier refrigerant flow channel adopts a variable cross-section multi-return design. The height of the flow channel cross section decreases along the flow direction, and 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 change of the battery temperature, so that the cooling liquid can be more efficiently distributed in the battery pack, avoiding the situation that the temperature difference of the cooling liquid is too large and the local heat dissipation is insufficient in the traditional liquid cooling system, thereby improving the overall heat dissipation efficiency. Through this optimized flow channel design, the cold can be more evenly distributed, 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.

[0064] The double-stage cold distribution module includes a first-stage conical throttle valve and a second-stage micro-channel heat transfer pipe. The conical throttle valve is arranged in the inlet liquid collecting pipe, and dynamically adjusts the cold distribution according to the pressure of the carrier refrigerant inlet, so that the cooling liquid can flow to different parts of the battery according to the actual needs. The inner wall of the micro-channel heat transfer pipe is coated with a carbon nanotube coating, which has good thermal conductivity, thereby enhancing the heat exchange effect, and is hard connected with the battery cooling plate through a quick connection joint, thereby ensuring the stability and tightness of the system. Through this cascading cold distribution design, accurate cooling of different battery monomers can be realized, the cooling effect is greatly improved, and the battery damage caused by overcooling or overheating is reduced.

[0065] The vehicle-mounted coupling thermal management module switches the phase change cooling circuit and the vehicle-mounted air conditioning circuit through an electromagnetic three-way valve, and adds a check valve at the outlet pipe of the charging pile coolant, thereby realizing the pre-charging cold storage mechanism using valley electricity. This design can pre-charge the system during off-peak electricity, store a certain amount of cold energy through phase change cooling, so as to quickly release during peak charging, reduce the burden on the power grid during charging, and improve the charging efficiency.

[0066] The intelligent control module dynamically adjusts the coolant flow and the switching logic of the circuit by detecting the deformation data of the phase change material through the battery surface temperature sensor, the coolant flow meter and the resistance strain gauge. This intelligent control system can accurately determine the temperature distribution and cooling demand of the battery according to real-time data, so as to adjust the cooling strategy in real time and ensure that the temperature is within a safe range. At the same time, the system also executes the residual cold recovery strategy after charging, optimizes the utilization of cold energy, reduces unnecessary energy consumption, and improves the overall energy efficiency of the system.

[0067] Through the coordinated work of each module, the heat generated during the battery charging process can be accurately controlled, and problems such as overheating and overcooling can be avoided, thereby improving the safety and efficiency of battery charging, prolonging the service life of the battery, and improving the overall performance and energy-saving effect of the system.

[0068] In one possible implementation, in the present embodiment, the height decrement rate of the flow channel cross section of the gradient flow channel unit is dynamically adjusted according to the real-time feedback of the inlet pressure and outlet flow rate of the coolant. This means that when the coolant flows into the flow channel, the system monitors the pressure at the inlet and the outlet flow rate, and adjusts the shape and size of the flow channel using these data to ensure that the flow rate at the end of the flow channel remains within a suitable range, avoiding low flow rates. Low flow rate may cause local solidification of the phase change material, 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, avoiding the solidification of the phase change material, thereby ensuring the stability and efficiency of the cooling system.

[0069] In order to optimize the balance between heat exchange efficiency and pressure drop, an experimental calibration method is used to determine the increment rate of the corrugated fin density. Specifically, a heat exchange efficiency model for the end section of the flow channel is first established, which takes into account factors such as the specific heat capacity of the coolant, the latent heat release rate of the phase change material, and the fluctuation range of the ambient temperature. Changes in these factors will directly affect the relationship between heat exchange efficiency and pressure drop. On this basis, through prototype testing, heat exchange efficiency and pressure drop data under different densities of corrugated fin configurations are collected, and the balance between them is further analyzed.

[0070] After experimental calibration, the system sets constraints that the heat exchange efficiency reduction rate cannot exceed 10%, and the pressure rise increase cannot exceed 15%. This means that during the design process, the goal is to maintain high efficiency of heat exchange efficiency while controlling the pressure drop not to be too large, so as to ensure that the overall performance of the system is within the optimal interval. Through this experimental verification and data fitting, the optimal interval of the increasing rate of the corrugated plate fin density is finally determined, so that under different flow rates, the system can balance the heat exchange efficiency and flow resistance, and improve the effect of thermal management.

[0071] The height of the flow channel cross section is dynamically adjusted to ensure that the flow rate is always within the appropriate range, effectively preventing local solidification of the phase change material, thereby ensuring the stability and high cooling performance of the system under different working conditions. Secondly, through precise experimental calibration and density increasing rate optimization, the relationship between heat exchange efficiency and fluid pressure drop is balanced, improving the heat exchange performance while avoiding energy loss. These optimization measures not only enable the system to quickly respond to different working conditions, but also maintain high efficiency and stable performance during long-term operation, improving the overall thermal management effect, prolonging the service life of the battery, and improving the safety and efficiency during the charging process.

[0072] In one possible implementation, in the present embodiment, the surface tension coefficient and density of the composite phase change material in the 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. Then, the basic pore diameter, i.e. the initial size of the connecting holes, is calculated by combining the acceleration of gravity. The calculation of the basic pore diameter is based on the capillary force theory, which 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 diameter. The basic pore diameter provides a preliminary reference value for subsequent pore diameter optimization.

[0073] Next, the wettability correction coefficient of the phase change material to the connecting plate material is calibrated through the contact angle experiment. The wettability correction coefficient describes the affinity of the material surface to the phase change liquid, i.e. the extent of the liquid spreading on the solid surface. The correction coefficient is negatively correlated with the wetting angle between the phase change material and the connecting plate material, meaning that the stronger the wettability of the phase change material, the larger the correction coefficient. Through the contact angle experiment, the wettability of the material can be quantified, and the pore diameter calculation result can be corrected, so that the actual pore diameter is more consistent with the actual flow demand.

[0074] Based on the product of the basic pore diameter and the correction coefficient, the final connecting pore diameter can be generated. In this way, the final pore diameter can more accurately match the flow rate driven by capillary force and the heat absorption rate of the coolant. Pore diameter that is too large or too small can lead to inappropriate flow rate, thereby affecting the cooling effect; therefore, through accurate calculation and correction, the flow rate and heat exchange demand can be matched, avoiding the problem of phase change material not being able to absorb heat in time due to low flow rate, or uneven cooling due to high flow rate.

[0075] By precisely calculating the connected aperture, the flow of liquid phase change material within the honeycomb structure can be ensured to be smoother, avoiding the problem of local cooling failure caused by insufficient capillary force. At the same time, the optimized aperture design is matched with the heat absorption rate of the phase change material, improving the thermal management performance of the entire vehicle charging device. Ultimately, this fine aperture calculation and optimization not only improves the charging efficiency, but also prolongs the service life of the battery and improves the safety and reliability of the system.

[0076] In one possible implementation, the peak heat generation power of the battery pack is first calculated. This process is done by multiplying the battery's charge-discharge rate by the battery's internal resistance. The charge-discharge rate reflects the rate at which the battery discharges or charges, while the battery's internal resistance determines the extent to which the battery generates heat during charging and discharging. Through these two parameters, the heat release rate of the battery pack at maximum power can be obtained, providing basic data for the design of the cooling system.

[0077] Secondly, the model needs to determine the latent heat release rate of the phase change material. This rate is obtained by multiplying the solidification ratio with the real-time total latent heat value of the phase change material. As the phase change process of the phase change material (such as the change from liquid to solid), a certain amount of latent heat will be released or absorbed. The solidification ratio describes the degree of phase change material conversion to solid at a certain time, while the total latent heat value reflects the heat released during the complete solidification of the material. Therefore, by monitoring the solidification ratio and latent heat value in real time, the heat release rate of the phase change material can be accurately calculated, thereby optimizing the cooling effect.

[0078] The ambient temperature compensation coefficient is obtained by fitting the temperature-heat dissipation efficiency curve based on the historical data of the vehicle temperature control system. As the ambient temperature changes, the heat dissipation efficiency will also change, so the temperature compensation coefficient can adjust the cooling demand of the system according to the current vehicle temperature and environmental conditions. For example, when the external temperature is high, the temperature control system may need higher cooling efficiency, and the temperature compensation coefficient can help adjust the heat dissipation capacity of the system to adapt to different working environments.

[0079] Through the input of the above parameters, the unit time cold demand distribution model can calculate the required number of microchannels. The distribution of cold demand takes into account the comprehensive influence of battery heat generation, phase change material heat release, and environmental factors. By optimizing the number of microchannels, the system can maintain a low pressure drop while improving heat exchange efficiency, thereby ensuring that the battery pack maintains a safe and efficient temperature range during charging.

[0080] 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 the change in ambient temperature, the system's thermal management capabilities can be significantly improved. Second, by adjusting the cooling system in real-time to adapt to different ambient temperatures and charging states, the cooling effect is optimized and energy utilization efficiency is improved. In addition, precise cold demand allocation can also avoid unnecessary energy waste, thereby improving the overall performance of the system and the service life of the battery. These innovative measures enable the phase change cold storage vehicle-mounted charging device to provide higher cooling efficiency and better temperature control effect in practical applications, ensuring the safety and reliability of the vehicle during charging.

[0081] In one possible implementation, when the difference between the highest temperature and the lowest temperature of the battery pack exceeds a preset temperature difference threshold, the intelligent control module starts the variable flow pump to adjust the flow of the refrigerant. The temperature difference threshold can be set according to specific application scenarios to ensure the temperature uniformity of the battery pack. When the temperature difference is too large, it means that the battery pack is overheating in some areas, and the cooling efficiency needs to be improved by adjusting the flow. The adjustment range is dynamically generated based on the temperature difference suppression efficiency mapping table trained by historical charging data. This mapping table optimizes the temperature difference suppression strategy through analysis of historical charging data, making the flow adjustment more accurate and efficient.

[0082] When the highest temperature of the battery pack exceeds the activation threshold of the phase change cooling, the intelligent control module switches to the phase change cooling circuit and increases the flow to improve the cooling efficiency. Dynamic adjustment of the activation threshold is one of the cores 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 fully released heat, and at this time, strong cooling needs to be started earlier to avoid high 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.

[0083] After charging is completed, the intelligent control module controls the extraction time and air volume of the vehicle-mounted air conditioner fan according to the residual cold of the phase change module and the target temperature drop value of the passenger compartment. The phase change module will accumulate a certain amount of cold during charging, and after charging is completed, if the temperature inside the vehicle is high, the system will use this residual cold to lower the temperature inside the vehicle to the target value through the air conditioner fan. By accurately controlling the extraction time and air volume of the fan, the system can effectively adjust the temperature inside the vehicle while avoiding energy waste.

[0084] The intelligent control logic enables precise temperature control and cooling management, ensuring that the battery pack's temperature remains within a safe range during charging, thereby improving charging efficiency and battery lifespan. When the battery pack's temperature difference is too large, the system adjusts the refrigerant flow to balance the temperature distribution of the batteries, effectively preventing local overheating. The switching and increased flow of the phase change cooling circuit can quickly respond when the battery temperature exceeds the preset threshold, ensuring stable temperature control during charging. The air conditioning temperature adjustment after charging not only improves the comfort of the vehicle interior but also optimizes the efficiency of cold energy use, avoiding unnecessary energy waste. Overall, this control logic can improve the overall performance of the vehicle-mounted charging system and battery safety, while providing a more comfortable in-vehicle environment for passengers.

[0085] In one possible implementation, first, a mapping relationship between refrigerant flow and temperature difference suppression efficiency is constructed by analyzing historical charging data. This process uses a neural network model to train to accurately predict the cooling system's effect on battery pack temperature difference suppression under different flow conditions. The input variables for training include battery pack temperature distribution variance, environmental humidity, and charging current rate. Battery pack temperature distribution variance is a parameter that describes the differences between various temperature points within the battery pack, environmental humidity affects the change in cooling effect, and charging current rate is directly related to the heat generation rate of the battery pack.

[0086] During charging, the system collects the battery pack's temperature distribution variance in real time and obtains environmental humidity data through on-board environmental sensors. These sensors continuously monitor the battery pack's temperature state and provide accurate humidity values for the vehicle's interior environment. The larger the temperature distribution variance, the more uneven the heat distribution of the battery pack, and the cooling system needs to make corresponding adjustments.

[0087] The real-time collected data such as battery pack temperature distribution variance, environmental humidity, and charging current rate are input into the trained neural network model. This neural network model analyzes the relationship between input variables and flow adjustment effects and outputs the optimal flow adjustment ratio. In this way, the system can dynamically calculate the most suitable refrigerant flow based on the current state to effectively reduce the temperature difference within the battery pack, ensuring the safety of the battery and the efficiency of the charging process.

[0088] The output adjustment ratio also includes the adjustment direction. Specifically, the adjustment direction of the flow is positively related to the positive or negative value of the temperature distribution variance. If the temperature distribution variance is positive, it indicates that there is a large temperature difference within the battery pack, and the system needs to increase the flow to improve the cooling effect and balance the battery pack temperature; if the temperature difference variance is negative, it indicates that the battery pack temperature is relatively uniform, and the system may reduce the flow to save energy and avoid excessive cooling.

[0089] By dynamically adjusting the flow rate of the cold carrier, the system can respond to the temperature changes of the battery pack in real time, effectively suppress the situation of excessive temperature difference, thereby improving the charging efficiency and prolonging the service life of the battery. In addition, by using neural network model for training and real-time adjustment of flow, the system can accurately control the cooling effect according to the real-time data of environmental humidity, battery temperature and charging current, avoid excessive or insufficient cooling, and thus improve the energy utilization efficiency and charging safety. Overall, this technology improves the intelligent level of the phase change cold storage type vehicle-mounted charging device, making the temperature management more accurate and efficient.

[0090] In one possible implementation, the composite phase change material in the embodiment of the present application adopts a combination of paraffin, expanded graphite and epoxy resin, where paraffin is responsible for providing phase change energy storage capability, expanded graphite is used to improve thermal conductivity, and epoxy resin serves as the base material to ensure the structural stability of the composite material. In the ratio optimization, the goal is to maximize the latent heat value of the composite material (i.e. the heat absorption and release capacity during phase change), while ensuring that the thermal conductivity coefficient can reach a certain standard to achieve efficient heat conduction.

[0091] In order to determine the optimal ratio, a three-factor five-level orthogonal experiment design is adopted. The experimental factors include the proportions of paraffin, expanded graphite and epoxy resin, and five different levels are set for each factor, covering a variety of possible combinations. The advantage of orthogonal experiment is that it can obtain effective results with fewer experimental times, reducing experimental cost and improving efficiency.

[0092] After determining different ratio combinations, performance tests are conducted on each ratio, mainly testing three parameters:

[0093] Latent heat value: test the latent heat value of the material under each ratio to evaluate its heat storage and release during phase change.

[0094] Thermal conductivity: measure the thermal conductivity of the material to evaluate its heat transfer efficiency during charging. The addition of expanded graphite helps to improve the thermal conductivity.

[0095] Viscosity: viscosity is an important factor affecting the flowability of the material and the heat transfer efficiency during phase change. A rotary viscometer is used to continuously measure the viscosity within the phase change temperature range, ensuring that the material can maintain appropriate flowability during operation.

[0096] After all tests are completed, a weighted scoring method is used to comprehensively evaluate the performance of each ratio. The weight of latent heat value is set to ≥70%, and the weight of thermal conductivity is set to ≤30%, because latent heat value occupies a major position in the performance of phase change material, while thermal conductivity is a secondary factor. Through the weighted scoring method, each ratio can be quantitatively scored, and the ratio with the best comprehensive performance can be determined.

[0097] Through this optimization process, the performance of the composite phase change material is significantly improved. First, maximizing the latent heat value can ensure that the material effectively absorbs and releases heat during the charging process, enhancing the heat storage capacity of the system and improving the cooling efficiency. Second, the optimization of the thermal conductivity ensures the heat transfer performance of the material, allowing heat to quickly transfer from the battery pack to the cooling system, avoiding local overheating. Proper adjustment of the viscosity ensures good flowability of the material during the phase change process, avoiding excessive flow resistance that affects heat dissipation. Overall, this optimization scheme precisely adjusts the ratio of paraffin, expanded graphite and epoxy resin, so that the composite phase change material can meet the high latent heat energy storage while maintaining good thermal conductivity and flowability, thereby improving the thermal management performance and system reliability of the phase change cold storage type vehicle-mounted charging device.

[0098] In one possible implementation, in a vehicle-mounted charging device, the quick connection connector needs to maintain good sealing in a vibrating environment. In order to simulate the vibration in the actual use environment of the vehicle, first of all, test on the vibration table. The frequency range of the vibration table is set to 5-200Hz, and the acceleration is 3g. This frequency band covers the common vibration spectrum in the vehicle environment, such as engine operation and road unevenness. This test can accurately simulate the vibration conditions that the connector may encounter in actual use, ensuring its performance in this environment.

[0099] In the simulated vibration environment, test the sealing performance of the connector. During the test, the connector will be subjected to the vibration frequency and acceleration generated by the vibration table to simulate various vibration states that may occur during vehicle use. The core of the test is to determine whether the connector can maintain its original sealing effect under these vibration conditions.

[0100] In the sealing performance test, gradually increase the insertion force until the leakage rate of the connector exceeds the set sealing threshold. This process aims to find the maximum insertion force value of the connector during continuous insertion and removal operations. The insertion force refers to the force required to connect the connector, and excessive insertion force may cause the connector to fail or be damaged, so a critical value needs to be found.

[0101] During the gradual increase of the insertion force, when the leakage rate of the connector exceeds the set sealing threshold, it is considered that the sealing performance of the connector has reached a critical point. This insertion force value is the leakage critical insertion force, which is an important indicator of whether the sealing performance of the connector can be maintained under external vibration.

[0102] To ensure that the joint design meets the requirements for long-term use, the upper limit of the joint design insertion force is set to 90% of the leakage critical insertion force. This setting can ensure that the joint will not fail or be damaged due to excessive insertion force during normal use, thereby improving the reliability and safety of the system. Through this setting, frequent failures or water or gas leaks caused by excessive insertion force in actual use can be prevented.

[0103] By simulating the vehicle vibration spectrum for testing, the sealing performance of the joint in the vehicle environment can be ensured, even if vibrations occur during vehicle driving, the joint can still maintain a stable sealing state, avoiding leakage problems caused by vibrations. By setting the upper limit of the joint design insertion force to 90% of the leakage critical insertion force, it can effectively prevent sealing failure due to excessive insertion, prolong the service life of the device. Overall, this technical optimization improves the insertion performance of the vehicle charging device, enhances its adaptability in complex dynamic environments, and enables the device to maintain good sealing and performance stability over a long period of use.

[0104] In one possible implementation, one of the activation conditions for valley electricity pre-charging cold is that the real-time electricity price of the power grid is lower than the preset electricity price threshold. There are price fluctuations in the electricity market, and the electricity price of the power grid is usually low during the night or low-load period, so charging the vehicle cold storage device at this time has high economic efficiency. The charging pile communication module can obtain real-time data from the electricity market trading platform by connecting to the electricity market system to determine whether the current electricity price of the power grid is lower than the preset threshold. If the price is low, the system can trigger the pre-charging cold mechanism to charge the cold storage device using the low-price electricity, thereby reducing the charging cost and maximizing resource utilization.

[0105] Another activation condition is that the remaining cold storage capacity of the phase change material is lower than the safety margin threshold. To ensure that the vehicle charging system can still effectively cool for a long time, 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 demand of the next charging cycle, the cold storage device will be activated. Using deformation sensor data, the remaining cold storage capacity of the phase change material can be evaluated in real time by fitting with the solidification ratio model. 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 cold mechanism to supplement the cold storage capacity.

[0106] The pre-chilling mechanism also depends on whether the interval of the next planned charging time is greater than the effective duration of the cold storage. The vehicle navigation system can determine the time interval of the next charging through the predicted travel node time difference. If the planned charging time interval is greater than the effective duration of the cold storage material (i.e., the cooling capacity of the cold storage device will gradually decrease within the time interval), the system will start the pre-chilling function. In this way, the vehicle charging device has already supplemented the cooling capacity through the off-peak electricity price before charging, thereby ensuring that the cooling effect can be maintained during the charging process.

[0107] The core advantage of this activation condition mechanism is to intelligently manage the cold storage capacity of the vehicle charging device through reasonable time scheduling and electricity market price fluctuations. First, charging at off-peak electricity prices not only reduces charging costs but also improves energy utilization efficiency. Second, by monitoring the cold storage capacity in real time and predicting the charging period, the cold storage device can maintain optimal cooling effect during the charging process, avoiding reduced charging efficiency or excessive temperature affecting charging safety due to insufficient cold storage. Finally, combined with the prediction function of the vehicle navigation system, the charging time and cooling demand can be accurately determined, and the charging and cold storage operations can be reasonably scheduled to enhance the intelligence and adaptability of the vehicle charging device. This comprehensive mechanism improves the efficiency, stability, and energy saving of the charging system.

[0108] In one possible implementation, during actual use, there is a certain correlation between the temperature rise rate of the battery pack and the cooling capacity consumption coefficient of the phase change material. By statistically analyzing the temperature rise rate of the battery pack in historical charging cycles and combining the cooling capacity consumption of the phase change material in different charging cycles, the system can obtain the relationship between the two. This process can help the system accurately assess how the cooling effect of the phase change material affects the temperature rise of the battery pack under different charging loads, thereby providing important basic data for subsequent dynamic calculations.

[0109] The health status of the battery directly affects its temperature rise rate. The health status of the battery changes over time, such as battery aging, increasing number of charging times, and wear and tear, which can cause changes in the temperature rise rate. Therefore, to improve the accuracy of the calculation, the system needs to monitor the health status of the battery in real time and correct the predicted value of the temperature rise rate according to the current state of the battery. Through this correction process, the temperature rise prediction can be closer to the actual situation of the battery, avoiding the situation of insufficient or excessive temperature control due to changes in the health status of the battery.

[0110] To ensure the safe temperature control of the battery pack in the next charging cycle, the system will back-calculate the minimum cold storage capacity required according to the corrected temperature rise rate prediction value. This process needs to consider various factors, including charging current, charging time, ambient temperature, etc., to calculate the minimum cooling capacity required to maintain the battery temperature within a safe range under specific conditions.

[0111] Finally, the required minimum cold storage capacity is increased by 120% to set the safety margin threshold. This 120% margin is to ensure that sudden situations that may occur during charging, such as sudden increase in battery load or drastic change in environmental temperature, can provide sufficient cooling capacity to prevent safety problems caused by overheating of the battery. The purpose of setting the safety margin threshold is to provide additional safety for the on-board charging device to adapt to different use environments and battery states.

[0112] By considering historical data, battery health status and cooling capacity of phase change material, the system can dynamically adjust the safety margin threshold, ensuring that the on-board charging device can provide sufficient cooling capacity under various charging conditions, avoiding safety hazards caused by overheating or insufficient cooling of the battery. In addition, this process can achieve adaptive adjustment for different charging cycles, according to the health status of different batteries and charging load, real-time optimization of cooling capacity configuration, and improvement of the overall performance and safety of the on-board charging device. In summary, by dynamically calculating the safety margin threshold, the charging efficiency and battery life can be improved while ensuring safe temperature control, and the charging efficiency and battery life can be improved according to Fig. 3 It can be known that the temperature is lower and the control is more gentle during fast charging.

[0113] The present application encompasses any substitutions, modifications, equivalent methods and schemes made on the essence and scope of the present application. In order to make the public have a thorough understanding of the present application, specific details are described in the following preferred embodiments of the present application, and the present application can also be fully understood without the description of these details to those skilled in the art. In addition, in order to avoid unnecessary confusion to the essence of the present application, well-known methods, processes, procedures, elements and circuits, etc. are not described in detail.

[0114] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A phase change cold accumulation type vehicle-mounted charging device characterized by comprising: The application relates to a vehicle-mounted phase change thermal management system, which comprises the following modules which cooperate with each other: a composite phase change cold storage module, which comprises a multi-cavity honeycomb structure, the multi-cavity honeycomb structure is formed by welding a corrugated plate and a connecting plate to form a phase change material storage space, and the phase change material storage space is filled with a composite phase change material; the connecting plate is provided with an opening to connect adjacent honeycomb cavities, and liquid phase change material is driven to flow through capillary force; a gradient flow channel unit, which is integrated in the composite phase change cold storage module, the cold carrier flow channel adopts a variable cross-section multi-return design, the height of the cross section of the flow channel decreases along the flow direction, and the density of the corrugated plate fins increases along the flow direction; a two-stage cold quantity distribution module, which comprises a first-stage conical throttle valve and a second-stage micro-channel heat transfer pipe, the conical throttle valve is arranged in an inlet liquid collecting pipe, and branch flow is dynamically adjusted according to the inlet pressure of the cold carrier; the inner wall of the micro-channel heat transfer pipe is coated with a carbon nanotube coating, and the micro-channel heat transfer pipe is hard-connected with a battery cooling plate through a quick connection joint; a vehicle-mounted coupling thermal management module, which switches the phase change cooling circuit and the vehicle-mounted air conditioning circuit through an electromagnetic three-way valve, and an inverse check valve is additionally arranged at the outlet pipe of the cold carrier of a charging pile to realize the cold storage mechanism of pre-charging by valley electricity; an intelligent control module, which dynamically adjusts the cold carrier flow and the switching logic of the circuit based on the surface temperature sensor of the battery, the cold carrier flowmeter and the phase change material deformation data detected by the resistance strain gauge, and simultaneously executes the residual cold quantity recovery strategy after charging is completed. The height decreasing rate of the cross section of the flow channel of the gradient flow channel unit is dynamically adjusted according to the feedback values of the inlet pressure of the cold carrier and the outlet flow speed, so that the end flow speed is not lower than the critical flow speed for preventing local solidification of the phase change material; the density increasing rate of the corrugated plate fins is determined by experimentally marking the balance relationship between the heat exchange efficiency and the pressure drop of the end section of the flow channel, and specifically comprises the following steps: establishing a heat exchange efficiency model of the end section of the flow channel, and inputting parameters including the specific heat capacity of the cold carrier, the latent heat release rate of the phase change material and the environmental temperature fluctuation range; collecting the heat exchange efficiency and pressure drop data under different densities through sample test of the variable fin density; taking the heat exchange efficiency decreasing rate <=10% and the pressure rise increasing amplitude <=15% as constraint conditions, and fitting the optimal interval of the fin density increasing rate; the connecting hole diameter of the multi-cavity honeycomb structure is determined through a capillary force model, and specifically comprises the following steps: measuring the surface tension coefficient and the density of the composite phase change material in the liquid state, and calculating the basic hole diameter in combination with the gravitational acceleration; marking a material wettability correction coefficient through a contact angle experiment, and the correction coefficient is negatively correlated with the wetting angle of the phase change material to the connecting plate material; generating the final connecting hole diameter based on the product of the basic hole diameter and the correction coefficient, so as to ensure that the flow speed driven by the capillary force matches the heat absorption rate of the cold carrier.

2. The phase change cold accumulation type vehicle-mounted charging device according to claim 1, characterized in that, the number of micro-channels of the second-stage micro-channel heat transfer pipe is determined based on a unit time cold quantity demand distribution model, and the model input parameters comprise: the peak heat generation power of the battery pack, which is calculated by multiplying the battery charging and discharging rate and the internal resistance; the latent heat release rate of the phase change material, which is obtained by multiplying the solidification proportion and the total latent heat value in real time; an environmental temperature compensation coefficient, which is obtained by mapping a temperature-heat dissipation efficiency curve fitted according to historical data of the vehicle-mounted temperature control system.

3. The phase change cold accumulation type 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 temperature of the battery pack exceeds a preset temperature difference threshold, a variable flow pump is started to adjust the flow of the secondary refrigerant, and the adjustment range is dynamically generated based on a temperature difference suppression efficiency mapping table trained by historical charging data; When the maximum temperature of the battery exceeds a phase change cooling activation threshold, the phase change cooling loop is switched on and the flow is increased, and the activation threshold is dynamically corrected according to the real-time solidification ratio of the phase change material: the lower the solidification ratio, the lower the activation threshold to start strong cooling in advance; After charging is completed, the time length and air volume of the air fan of the vehicle-mounted air conditioner are controlled based on the residual cold capacity of the phase change module and the target temperature drop value of the passenger compartment.

4. The phase change cold accumulation type vehicle-mounted charging device according to claim 3, characterized in that, The adjustment range of the variable flow pump is dynamically generated by the following process: A secondary refrigerant flow-temperature difference suppression efficiency mapping table is constructed, and historical charging data is trained based on a neural network model, and the input variables include the temperature distribution variance of the battery pack, the environmental humidity and the charging current rate; The temperature distribution variance of the battery pack is collected in real time, and the humidity data is obtained through the vehicle-mounted environmental sensor; The input variables are input into the trained neural network model, and the optimal flow adjustment ratio is output, and the adjustment direction is positively correlated with the positive or negative value of the temperature distribution variance.

5. The phase change cold accumulation type vehicle-mounted charging device according to claim 1, characterized in that, The composite phase change material is a paraffin-based composite material, and the component ratio is determined by orthogonal test optimization: The orthogonal table of three factors and five levels of paraffin, expanded graphite and epoxy resin is set to maximize the latent heat value and meet the optimization target of the thermal conductivity coefficient; The latent heat value, thermal conductivity coefficient and viscosity under different ratios are tested, and the viscosity is continuously measured by a rotary viscometer in the phase change temperature interval; The optimal ratio of comprehensive performance is calculated by the weighted scoring method, and the latent heat value weight is ≥70% and the thermal conductivity coefficient weight is ≤30%.

6. The phase change cold accumulation type vehicle-mounted charging device according to claim 1, characterized in that, The plug-in force critical value of the quick connection joint is determined by vibration adaptability test: The joint sealing performance is tested on a vibration table with a frequency of 5-200 Hz and an acceleration of 3g to simulate the vehicle-mounted vibration spectrum; The plug-in force is gradually increased until the leakage rate exceeds the sealing threshold, and the critical plug-in force of leakage is recorded; 90% of the critical plug-in force is set as the upper limit of the designed plug-in force of the joint.

7. The phase change cold accumulation type vehicle-mounted charging device according to claim 1, characterized in that, The activation conditions of the regenerator mechanism using valley electricity pre-chilling include: The real-time electricity price of the power grid is lower than the preset electricity price threshold, and the power market transaction platform data is obtained through the charging pile communication module; The residual regenerative capacity of the phase change material is lower than the safety margin threshold, which is calculated by the deformation sensor data and the solidification ratio fitting model; The next planned charging time interval is greater than the regenerative effective time length, which is determined by the travel node time difference predicted by the vehicle-mounted navigation system.

8. The phase change cold accumulation type vehicle-mounted charging device according to claim 7, characterized in that, The safety margin threshold is dynamically calculated by the following process: The correlation between the average temperature rise rate of the battery pack and the cold consumption coefficient of the phase change material in the historical charging period is statistically analyzed; The temperature rise rate prediction value is corrected according to the current battery health state; The minimum regenerative capacity required to maintain safe temperature control in the next charging period is back calculated as a constraint, and 120% of it is set as the safety margin threshold.

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