Cooperative control method and system for low-temperature charging of electric vehicle

Abstract

The invention discloses an electric vehicle low-temperature charging cooperative control method and system. The method comprises the following steps: determining battery allowable charging power based on a battery SOC and a battery temperature; if the battery allowable charging power is greater than or equal to the vehicle-mounted charging power, not heating the battery, continuously charging the battery, and returning to the step of determining the battery allowable charging power based on the battery SOC and the battery temperature; if the allowable charging power of the battery is smaller than the vehicle-mounted charging power, the battery is heated until the temperature of the battery reaches the reference target temperature, and the heating power of the battery is controlled in a predictive gradient heating mode so that heating and heat dissipation of the battery can be balanced until the SOC of the battery reaches 100%. The method has the advantages that the charging efficiency and safety in a low-temperature environment are improved, and the battery is prevented from being exhausted.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electric vehicle battery management, and particularly relates to a low-temperature charging collaborative control method and system for electric vehicles. BACKGROUND

[0002] When an electric vehicle is subjected to slow charging in a low-temperature environment, it faces many technical problems. Due to the increased viscosity of the electrolyte and the reduced ion migration rate of the lithium ion battery under low-temperature conditions, the internal resistance of the battery is significantly increased, which greatly reduces the allowable charging power of the battery. In order to improve the charging efficiency, the battery usually needs to be heated at the same time. However, the power of the on-board charger (OBC) is limited. When the battery heating power exceeds the OBC power, the battery is actually in a discharging state, which may cause the battery to run out of power when the battery has a low power, causing serious problems such as power failure of the vehicle high-voltage system and even breakdown.

[0003] The existing solutions in the industry have obvious defects: the static power limiting method sets the heating power to be no more than 50% of the self-heating power, but fails to consider the influence of the dynamic change of the state of charge (SOC) of the battery, and there is still a risk of power depletion in the low-power range; the traditional PID temperature control method does not combine the charging power map for predictive control, resulting in a lag in heating response and easy occurrence of temperature overshoot; and the existing technology lacks consideration of battery heat dissipation compensation, especially when the ambient temperature is lower than-20℃ in a high-cold region, due to the lack of an accurate environmental heat dissipation model, resulting in a significant increase in heating energy consumption. These technical defects seriously restrict the charging efficiency and safety of electric vehicles in low-temperature environments.

[0004] In view of the above problems, the existing technology needs to be improved. SUMMARY

[0005] The purpose of the present application is to solve the problems in the background art, and to provide a low-temperature charging collaborative control method and system for electric vehicles, a computer device and a storage medium, which have the advantages of improving the charging efficiency and safety in low-temperature environments and avoiding battery power depletion.

[0006] The technical solution adopted by the present application is as follows: a low-temperature charging collaborative control method for electric vehicles, comprising the following steps: determining the allowable charging power of the battery based on the SOC and the temperature of the battery; if the allowable charging power of the battery is greater than or equal to the on-board charging power, the battery is not heated, the battery is continuously charged, and the step of determining the allowable charging power of the battery based on the SOC and the temperature of the battery is returned to; If the battery's allowable charging power is less than the vehicle's charging power, the battery is heated until the battery temperature reaches the baseline target temperature. A predictive gradient heating method is used to control the battery heating power to balance the battery's heating and heat dissipation until the battery's SOC reaches 100%.

[0007] Furthermore, the allowable charging power of the battery is determined by looking up the SOC-Temperature-Allowable Charging Power MAP table based on the battery SOC and battery temperature.

[0008] Furthermore, the first heating power P for heating the battery heat_1 Determined based on the battery's state of charge (SOC): If SOC < SOC1, then P heat_1 =A1×P obc ; If SOC1 ≤ SOC < SOC2, then P heat_1 =P obc -B1×(SOC2-SOC)×P obc ; If SOC ≥ SOC², then P heat_1 The maximum power that allows the battery to heat up; Where SOC is the real-time battery SOC value; SOC1 and SOC2 are the set first and second SOC thresholds, respectively; P obc The on-board charging power is denoted by A1 and B1, which are the first and second power coefficients, respectively, where A1 < 1 and B1 < 0.1.

[0009] Furthermore, the process for determining the reference target temperature is as follows: Query the SOC-Temperature-Allowable Charging Power MAP table to determine all critical battery temperatures corresponding to the allowable charging power of the battery with the same on-board charging power, and use the minimum temperature value among all critical battery temperatures as the benchmark target temperature.

[0010] Furthermore, the method of controlling the battery heating power using predictive gradient heating to balance battery heating and heat dissipation includes: Controlling the battery temperature to maintain at T i ; Predict whether there is a state of charge (SOC) critical point that requires preheating of the battery; If present, after the battery's SOC reaches the critical SOC point, increase the battery heating power until the battery temperature reaches T. i+1 , will T i Updated to T i+1 To determine whether the battery's SOC has reached 100%; If not, then determine whether the battery SOC has reached 100%; If the battery's SOC has not reached 100%, the system will return to control the battery temperature to maintain at T. i Steps; Among them, T i This represents the preset target temperature for temperature rise, where i is the number of the target temperature, starting from 1. i+1 >T i .

[0011] Furthermore, the controlled battery temperature is maintained at T i The second battery heating power P heat_2 Determined by the following formula: P heat_2 =hA×(T i -Tenv); Where hA is the battery heat dissipation coefficient; Tenv is the ambient temperature.

[0012] Furthermore, the prediction of whether there is a SOC critical point requiring preheating of the battery includes: Based on battery SOC and T i Locate the SOC-Temperature-Allowable Charging Power MAP table and determine the temperature range in the MAP table at T. i If there is an allowable charging power lower than the vehicle charging power among all allowable charging powers corresponding to the battery SOC, then it is predicted that there is an SOC critical point that requires preheating of the battery; otherwise, it is predicted that there is no SOC critical point that requires preheating of the battery.

[0013] Furthermore, if there exists a SOC critical point that requires preheating of the battery, the SOC value of the SOC critical point is determined by the following formula: (SOC i -SOC 点 ) / v soc_i =(T i+1 -T i ) / V T ; Among them, SOC i To maintain the battery temperature at T i At that time, the battery's allowable power obtained from the table is less than the SOC value corresponding to the on-board charging power at that moment; SOC 点 v is the SOC value at the critical point of SOC. soc_i For battery temperature from T i Upgrade to T i+1 The rate of change of SOC during the process is related to the battery charging power and the battery heating power; V T For battery SOC from SOC 点 Rise to SOC iThe rate of temperature rise during the process is related to the battery heating power.

[0014] Furthermore, the third heating power P of the battery after increasing the battery heating power... heat_3 Determined based on the battery's state of charge (SOC): If SOC < SOC1, then P heat_3 =A1×P obc ; If SOC1 ≤ SOC < SOC2, then P heat_3 =P obc -B1×(SOC2-SOC)×P obc ; If SOC ≥ SOC², then P heat_3 The maximum power that allows the battery to heat up; Where SOC is the real-time battery SOC value; SOC1 and SOC2 are the set first and second SOC thresholds, respectively; P obc The on-board charging power is denoted by A1 and B1, which are the first and second power coefficients, respectively, where A1 < 1 and B1 < 0.1.

[0015] A low-temperature charging collaborative control system for electric vehicles, comprising: A permissible charging power determination module is used to determine the permissible charging power of the battery based on the battery SOC and battery temperature. The charging module determines the difference between the battery's allowable charging power and the vehicle's charging power. If the allowable charging power is greater than or equal to the vehicle's charging power, the battery is charged only. If the allowable charging power is less than the vehicle's charging power, a gradient heating signal is sent to the predictive gradient heating module while the battery is being charged. The predictive gradient heating module is used to heat the battery until the battery temperature reaches the reference target temperature when a gradient heating signal is received. The predictive gradient heating method controls the battery heating power to balance the heating and heat dissipation of the battery until the battery SOC reaches 100%.

[0016] A computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the electric vehicle low-temperature charging coordinated control method as described above.

[0017] A storage medium storing a computer program that, when executed by a processor, implements the steps of the electric vehicle cryogenic charging coordinated control method as described in any of the preceding claims.

[0018] The beneficial effects of this invention are as follows: This invention achieves a balance between charging efficiency and safety in low-temperature environments by dynamically adjusting the synergistic relationship between battery heating power and on-board charging power, thus avoiding battery depletion and improving the reliability of the charging process. Attached Figure Description

[0019] Figure 1 This is a flowchart of the control method of the present invention. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0021] In existing technologies, there is a mismatch between battery heating power and charging power during slow charging of electric vehicles at low temperatures. Traditional methods employ fixed power limits or delayed temperature control, leading to the risk of battery depletion during low-charge phases, overcharging due to delayed temperature regulation response, and significantly increased heating energy consumption in extremely cold regions. Especially in scenarios where on-board charger power is limited, static heating strategies struggle to adapt to dynamic changes in battery state of charge, and conventional heat dissipation compensation mechanisms lack environmental temperature adaptability.

[0022] To address these issues, researchers discovered that the root cause lies in the static decoupling control of charging power and heating power. By analyzing the coupling relationship between the battery's thermodynamic and electrochemical characteristics, they recognized the necessity of establishing a dynamic correlation model between charging power and battery state. Further research revealed the nonlinear characteristics of the battery's allowable charging power to vary with temperature and state of charge, providing a theoretical basis for dynamic coordinated control. Based on this, they proposed using the battery's real-time state parameters as the core variables for coordinated control, achieving dynamic optimization of energy distribution through predictive gradient heating.

[0023] Therefore, this invention proposes a low-temperature charging cooperative control method for electric vehicles, such as... Figure 1 As shown, it includes the following steps: Determine the allowable charging power of the battery based on battery SOC and battery temperature; If the battery's allowable charging power is greater than or equal to the vehicle's charging power, then the battery will not be heated, the battery will continue to be charged, and the process will return to the step of determining the battery's allowable charging power based on the battery's SOC and battery temperature. If the battery's allowable charging power is less than the vehicle's charging power, the battery is heated until the battery temperature reaches the baseline target temperature. A predictive gradient heating method is used to control the battery heating power to balance the battery's heating and heat dissipation until the battery's SOC reaches 100%.

[0024] The battery's allowable charging power refers to the maximum safe charging power acceptable to the battery under its current state. This can be obtained in real-time by querying a pre-set state-of-charge-temperature-power mapping table. This parameter comprehensively reflects the battery's polarization characteristics and thermal stability limitations. The benchmark target temperature refers to the minimum critical temperature required for the battery's allowable charging power to reach the onboard charging power. This minimum critical temperature value is determined by reversely querying the mapping table, ensuring the economic efficiency of the heating target. Predictive gradient heating is a control strategy that increases the battery temperature in stages. It adjusts the heating power in advance by calculating the temperature rise requirement at future state points. This can be implemented using a feedforward-feedback composite control algorithm, which effectively avoids temperature overshoot.

[0025] Specifically, the system continuously monitors battery state of charge (SOC) and ambient temperature parameters, obtaining the real-time allowable charging power through a lookup table. When the allowable power is detected to be lower than the onboard charging power, a temperature boosting program is initiated, first heating the battery to a baseline target temperature. During this process, the heating power is dynamically adjusted based on the predicted temperature rise requirements for subsequent charging stages according to the current SOC, maintaining a balance between battery heat dissipation and heating power. When the SOC reaches a preset inflection point, the heating power reserve is increased in advance to ensure a smooth temperature transition in subsequent charging stages. The entire control process forms a closed-loop feedback loop, continuously correcting the heating strategy until charging is complete.

[0026] This invention achieves dynamic power allocation by establishing a two-parameter correlation model, introduces a feedforward mechanism for predictive gradient heating to effectively eliminate the temperature hysteresis effect, and achieves precise control of heating energy consumption by establishing a mathematical model of heat dissipation coefficient and ambient temperature.

[0027] Through the above technical solution, this invention effectively prevents the risk of battery over-discharge caused by excessive heating power during low-temperature slow charging, and solves the temperature overshoot problem existing in traditional control methods. While ensuring charging safety, it significantly reduces ineffective heating energy consumption in cold environments, achieving synergistic optimization of charging efficiency and energy utilization.

[0028] This invention further proposes to determine the allowable charging power of a battery by looking up a SOC-temperature-allowable charging power MAP table based on the battery's SOC and battery temperature.

[0029] Here, SOC refers to the battery's state of charge, which can be calculated by integrating voltage and current data collected in real time by the battery management system, characterizing the battery's current energy storage level. Temperature refers to the real-time temperature value of the battery cell or module, which can be monitored at multiple points using temperature sensors placed inside the battery, reflecting the thermal state of the battery's operating environment. The SOC-Temperature-Allowable Charging Power MAP table is a two-dimensional data mapping table pre-calibrated through battery charge-discharge characteristic experiments. It can be implemented by constructing a matrix structure using allowable charging power values ​​under different SOC and temperature combinations, establishing a dynamic correlation between battery state parameters and charging power.

[0030] Specifically, by acquiring battery SOC and temperature parameters in real time as input conditions, two-dimensional interpolation is performed in a pre-calibrated MAP table to match the allowable charging power corresponding to the current state. When the battery is in a low-temperature environment, the MAP table dynamically adjusts the allowable charging power according to the real-time changes in SOC. This mechanism, by using SOC and temperature as joint input variables, allows the set value of the charging power to be updated in real time with changes in battery energy storage state and environmental conditions, thereby avoiding the problem of uncontrolled discharge in the low SOC range caused by fixed power limits.

[0031] This invention achieves real-time matching between charging power and battery state of energy by introducing a MAP table that correlates SOC and temperature. Through this technical solution, the invention enables adaptive adjustment of charging power based on battery state of energy and ambient temperature, ensuring that the charging power remains within safe limits across different SOC ranges.

[0032] The present invention further proposes a first heating power P for heating the battery. heat_1 Determined based on the battery's state of charge: If SOC < SOC1, then P heat_1 =A1×P obc ; If SOC1 ≤ SOC < SOC2, then P heat_1 =P obc -B1×(SOC2-SOC)×P obc ; If SOC ≥ SOC², then P heat_1 The maximum power that allows the battery to heat up; Where SOC is the real-time battery SOC value; SOC1 and SOC2 are the set first and second SOC thresholds, respectively; P obc The on-board charging power is defined as follows: A1 and B1 are the first and second power coefficients, respectively, both of which are calibrated values. Among them, A1 < 1, preferably A1 = 0.6-0.8, and B1 < 0.1, preferably B1 = 0.02-0.06.

[0033] SOC1 refers to the critical value that defines the low state of charge (SOC) range. Specifically, it can be implemented using the SOC value corresponding to the battery's safe discharge boundary, used to limit heating power during low charge stages to prevent over-discharge. SOC2 refers to the critical value that defines the high SOC range. Specifically, it can be implemented using the SOC value corresponding to the battery's charging efficiency inflection point, used to remove heating power limitations during high charge stages to increase the rate of temperature rise. On-board charging power refers to the fixed charging power output of the on-board charger, which can be obtained from charger specifications or real-time power monitoring data, serving as a benchmark reference value for heating power adjustment. The maximum allowable battery heating power refers to the highest heating power that the battery thermal management system can provide, which can be determined by the heater's rated power or the battery's temperature rise safety limit, used to maximize heating efficiency within a safe range.

[0034] Specifically, when the state of charge (SOC) is below SOC1, the heating power is limited to a fixed percentage of the onboard charging power, thus reducing heating demand and preventing excessive net discharge due to simultaneous charging and heating. When the SOC rises to between SOC1 and SOC2, the heating power increases linearly with increasing SOC, dynamically adjusting to ensure a complementary relationship between heating and charging power, maintaining a balance in total battery power consumption. When the SOC exceeds SOC2, the heating power switches to its maximum value to accelerate battery temperature rise. At this point, the battery has sufficient charge reserves, allowing for a priority increase in heating power. This segmented control strategy dynamically adjusts the heating power based on real-time feedback from the SOC, ensuring a match between heating demands and charging safety at different charge levels.

[0035] The heating power is dynamically limited based on the changes in SOC, and the specific thresholds are shown in Table 1.

[0036] Table 1. Power limiting strategy based on SOC hierarchical structure. This invention achieves dynamic constraint on heating power through state-of-charge (POC) threshold division. By controlling the correlation between POC and heating power, it proactively reduces heating power during low-charge stages to avoid the risk of battery depletion. Through this technical solution, the invention dynamically adjusts heating power based on the battery's real-time POC during low-temperature charging. In the low POC stage, power limiting prevents over-discharge, while in the medium-to-high POC stages, heating capacity is gradually released, ensuring both charging safety and improved heating efficiency during high-charge stages.

[0037] This invention further proposes the following process for determining the benchmark target temperature: Query the SOC-Temperature-Allowable Charging Power MAP table to determine all critical battery temperatures corresponding to the allowable charging power of the battery with the same onboard charging power. The minimum temperature value among all critical battery temperatures that is greater than the battery temperature is taken as the benchmark target temperature T. target .

[0038] The critical battery temperature refers to the temperature threshold at which the battery's allowable charging power equals the vehicle's charging power under specific SOC conditions. This parameter reflects the dynamic balance between charging power and temperature. The reference target temperature refers to the minimum temperature limit required to achieve charging power matching. By selecting the minimum value from the set of critical temperatures, heating energy consumption can be minimized while meeting charging requirements.

[0039] Specifically, during low-temperature charging, the system iterates through the data points in the SOC-Temperature-Allowable Charging Power MAP table to select all temperature values ​​where the allowed charging power equals the current onboard charging power. Since the critical temperatures corresponding to different SOCs vary, the minimum temperature value (greater than the current battery temperature) is selected as the heating target, which avoids energy waste caused by setting the temperature too high.

[0040] This invention achieves precise optimization of temperature setpoints by dynamically querying the MAP table and selecting the minimum critical temperature under multiple SOC conditions. Compared to static temperature control strategies, this method avoids ineffective heating caused by excessively high temperature settings in the low SOC stage, while preventing increased energy consumption due to temperature redundancy in the high SOC stage.

[0041] Through the above technical solution, this invention dynamically matches the critical temperature parameters between the on-board charging power and the battery's allowable charging power, thereby controlling the heating target temperature to the minimum necessary level while ensuring charging power requirements are met, significantly reducing energy loss during battery heating. Simultaneously, based on the minimum temperature selection mechanism under multiple SOC conditions, it avoids the risk of charging interruptions caused by temperature setting deviations in traditional methods, improving charging reliability in low-temperature environments.

[0042] This invention further proposes a predictive gradient heating method to control the battery heating power to achieve a balance between battery heating and heat dissipation, including the following steps: Controlling the battery temperature to maintain at T i ; Predict whether there is a state of charge (SOC) critical point that requires preheating of the battery; If present, after the battery's SOC reaches the critical SOC point, increase the battery heating power until the battery temperature reaches T. i+1 , will T i Updated to T i+1To determine whether the battery's SOC has reached 100%; If not, then determine whether the battery SOC has reached 100%; If the battery's SOC has not reached 100%, the system will return to control the battery temperature to maintain at T. i Steps; Among them, T i This represents the preset target temperature for temperature rise, where i is the number of the target temperature, starting from 1. i+1 >T i T1≥T target When T1=T target At that time, the battery temperature begins to execute a predictive gradient heating strategy from the moment T1 is reached, and when T1 > T target When the battery temperature reaches T target The battery is then continuously heated at the first heating power until the temperature reaches T1, and then the predictive gradient heating strategy is implemented.

[0043] Among them, controlling the battery temperature to be maintained at T i This refers to stabilizing the battery temperature at a preset target temperature by adjusting the heating power. Specifically, this can be achieved using a power compensation formula based on the heat dissipation coefficient, for example, setting the heating power to be equal to the heat dissipation power to maintain a constant temperature. This feature avoids temperature overshoot by balancing heating and heat dissipation. Predicting the existence of a SOC critical point requiring preheating involves dynamically determining whether preheating is necessary for future charging stages based on the charging power MAP table. This can be achieved by querying the critical point at which the charging power can change with SOC at the current temperature. This feature, combined with a charging power prediction model, identifies SOC change trends in advance, preventing charging interruptions due to heating delays. i+1 >T i This refers to a gradual increase in the target temperature, which can be achieved by using a preset sequence of multiple temperature thresholds, such as setting multiple target temperatures at 5°C intervals. This feature enables precise adjustment of the heating process through staged temperature control.

[0044] Specifically, during battery charging, the temperature is first maintained at the initial target temperature T. i At this point, the heating power and heat dissipation power are balanced. By querying the charging power MAP table in real time, it is determined whether there is a critical point at the current temperature where the allowable charging power is lower than the on-board charging power due to changes in SOC. If such a critical point exists, the heating power is actively increased when the battery SOC approaches the critical value, raising the temperature to the next gradient target temperature T. i+1Simultaneously, the target temperature parameter is updated. This process is repeated until the battery is fully charged, all temperature rise gradients are completed, there is no SOC critical point, or the charging device is disconnected to terminate charging. If no critical point exists, the current temperature is maintained until charging is complete. This method dynamically predicts the relationship between SOC and temperature, proactively adjusting the heating strategy before the charging power decreases, thus avoiding temperature fluctuations caused by response lag in traditional control.

[0045] This invention combines the prediction mechanism of the charging power MAP table to decompose the temperature rise target into a multi-stage gradient. When the SOC changes to the critical point, the heating power is actively adjusted, which avoids the lag in temperature control and prevents the risk of power consumption in the low SOC segment.

[0046] Through the above technical solution, this invention solves the problems of heating delay and temperature overshoot caused by unpredictable changes in charging power during low-temperature charging. Furthermore, by combining gradient temperature control with SOC critical point prediction, it avoids the risk of battery depletion at low SOC levels. The dynamic query mechanism of the charging power MAP table ensures real-time matching between heating power adjustments and battery state changes, and the staged temperature rise control achieves a continuous balance between the heating process and heat dissipation capacity.

[0047] This invention further proposes a method to control the battery temperature and maintain it at T. i The second battery heating power P heat_2 Determined by the following formula: P heat_2 =hA×(T i -Tenv); Where hA is the battery heat dissipation coefficient; Tenv is the ambient temperature.

[0048] The battery heat dissipation coefficient refers to the heat dissipation capacity of the battery system under a unit temperature difference. This can be achieved through experimental testing or thermodynamic model calibration, and is used to quantify the battery's own heat dissipation characteristics. Ambient temperature refers to the real-time temperature of the external space where the battery is located. This can be achieved by collecting data from a temperature sensor and inputting it into the control system, reflecting the heat dissipation conditions under actual operating conditions. The target temperature rise is the setpoint for the battery temperature to be maintained. This can be determined through table lookup or predictive algorithms, and is used to guide the adjustment of heating power.

[0049] Specifically, during battery charging, when it's necessary to maintain the target temperature, the control system dynamically calculates the minimum heating power required to maintain the target temperature based on real-time ambient temperature data and a preset battery heat dissipation coefficient. This calculation process is based on the principle of thermal balance, matching the heating power with the heat dissipation power to achieve a dynamic balance between heating and heat dissipation at the target temperature. For example, when the ambient temperature decreases, the difference between the target temperature and the ambient temperature increases, and the heating power increases accordingly to compensate for the increased heat dissipation loss; when the ambient temperature rises, the difference decreases, and the heating power automatically decreases to avoid energy waste.

[0050] This invention introduces a closed-loop regulation mechanism by incorporating the product relationship between the heat dissipation coefficient and ambient temperature, which can automatically optimize the heating power output based on real-time environmental changes. Through this technical solution, the invention achieves dynamic matching between heating power and heat dissipation conditions, maintaining the target temperature while avoiding energy waste caused by overheating, and significantly reducing the heating energy consumption of the battery system, especially in cold regions.

[0051] This invention further proposes a method for predicting whether there is a SOC critical point that requires preheating of the battery, including: based on the battery SOC and T... i Locate the SOC-Temperature-Allowable Charging Power MAP table and determine the temperature range in the MAP table at T. i If there is an allowable charging power lower than the vehicle charging power among all allowable charging powers corresponding to the battery SOC, then it is predicted that there is an SOC point that requires preheating of the battery; otherwise, it is predicted that there is no such SOC point.

[0052] The SOC-Temperature-Allowable Charging Power MAP table is a pre-established two-dimensional data table reflecting the allowable charging power of the battery under different combinations of SOC and temperature. It can be generated through experimental calibration or simulation modeling and is used to dynamically correlate battery state parameters with charging power limits. The preheated SOC critical point refers to the critical position where the battery SOC may trigger insufficient power during charging. It is determined by retrospectively tracing the critical conditions in the MAP table where the allowable charging power is lower than the on-board charging power, and is used to identify the risk of future charging power degradation in advance. The target temperature T is [not specified in the original text]. i This refers to the battery temperature setpoint that needs to be maintained at the current stage. Specifically, a stepped temperature control strategy can be adopted to gradually increase the setpoint to balance heating energy consumption and charging speed.

[0053] Specifically, this method monitors the battery's state of charge (SOC) and the current temperature control target (T) in real time. i Query the pre-stored MAP table data and filter out the data in T. iRecord all allowable charging power values ​​above the current SOC at the specified temperature. If a situation is found where the allowable charging power is lower than the vehicle's charging power, it is determined that insufficient power will occur when the SOC reaches the corresponding critical point during future charging. In this case, heating should be triggered at the SOC point before the critical point. For example, when the battery SOC is 30%, T... i At 10℃, a lookup of the MAP table reveals that the allowable charging power corresponding to a SOC of 40% is already lower than the onboard charging power. Therefore, it is determined that the battery heating power needs to be increased before the SOC reaches 40%. This means calculating the SOC critical point between 30% and 40% based on the SOC change rate and temperature rise rate, and increasing the heating power when the SOC reaches this critical point. This process couples the SOC change trend with temperature parameters, retrospectively tracing the power decay point in the MAP table to achieve real-time matching between heating actions and dynamic SOC changes.

[0054] This invention establishes a predictive model of SOC changes and power decay through forward lookup of MAP table data, enabling heating to occur before actual power insufficiency, effectively avoiding response delays and temperature overshoot. Through this technical solution, the invention can accurately predict the potential power decay critical point during battery charging, initiating the heating process before the SOC reaches the critical value. This avoids battery temperature fluctuations and low SOC depletion caused by heating delays, and simultaneously reduces unnecessary heating energy consumption by dynamically matching heating power with SOC change trends.

[0055] This invention further proposes that if there is a SOC critical point that requires preheating of the battery, the SOC value of the SOC critical point is determined by the following formula: (SOC i -SOC 点 ) / v soc_i =(T i+1 -T i ) / V T ; Among them, SOC i This refers to maintaining the battery temperature at T. i When the battery's allowable power obtained from the table is less than the SOC value corresponding to the vehicle's charging power at that moment, this can be achieved by consulting the SOC-Temperature-Allowable Charging Power MAP table, which represents the SOC critical value at which the allowable charging power is insufficient under the current temperature. 点 This refers to the SOC trigger value that requires preheating, specifically calculated using a dynamic equilibrium equation, and is used to trigger preheating when the SOC rises to the critical point. soc_i This refers to the battery temperature from T i Upgrade to T i+1The SOC change rate during the process is specifically related to the allocation ratio of battery charging power and heating power, reflecting the coupling relationship between SOC change and energy consumption. For example, SOC change rate (% / h) = [battery charging power (W) × charge / discharge efficiency] / [battery capacity (Wh)] × 100%, while battery charging power = on-board charging power - battery heating power. T This refers to the battery's SOC (State of Charge) from SOC (State of Charge). 点 Rise to SOC i The rate of temperature rise during the process is specifically determined by the battery heating power and is used to quantify the efficiency of temperature increase.

[0056] Specifically, this formula establishes a dynamic balance between the rate of change of SOC and the rate of temperature rise, thereby controlling the SOC... 点 With SOC i The percentage difference is related to the time required for the temperature to rise. When the SOC rises to SOC... 点 At that time, the system starts heating to raise the temperature to T. i+1 When SOC just reaches SOC i At this point, the allowed charging power will not fall below the onboard charging power, avoiding insufficient charging power due to temperature rise lag. v is calculated in real-time using the third heating power. soc_i and V T Dynamically adjust the trigger timing of the SOC point to ensure that the SOC is close to the SOC. i The temperature rise is completed beforehand. For example, when the battery is in a low-temperature environment and has a high SOC, v soc_i The higher proportion of charging power may slow down the rate of SOC increase; in this case, the SOC point can be appropriately shifted later. When the SOC is low, the increased proportion of heating power leads to a decrease in V. soc_i To speed things up, the SOC point needs to be triggered earlier to prevent the battery from running out.

[0057] This invention quantifies the dynamic coupling relationship between SOC and temperature rise, and predicts and adjusts the preheating trigger point in real time during the charging process. This avoids energy waste caused by heating too early and prevents charging interruption caused by heating too late.

[0058] Through the above technical solution, this invention can accurately predict the timing of preheating, completing the temperature rise before the battery's SOC reaches the critical SOC value, effectively avoiding the risk of power depletion due to delayed temperature rise during low-temperature charging. Simultaneously, by dynamically coordinating the power allocation between charging and heating, it prevents energy imbalance caused by overheating in the low SOC segment, improving the safety and efficiency of the charging process in low-temperature environments.

[0059] This invention further proposes that when the SOC point requiring preheating of the battery is predicted, the third heating power P of the battery should be increased. heat_3Adjust according to the battery's SOC, using the same method as described above (P). heat_1 Same, that is: If SOC < SOC1, then P heat_1 =A1×P obc ; If SOC1 ≤ SOC < SOC2, then P heat_1 =P obc -B1×(SOC2-SOC)×P obc ; If SOC ≥ SOC², then P heat_1 The maximum power that allows the battery to heat up; Where SOC is the real-time battery SOC value; SOC1 and SOC2 are the set first and second SOC thresholds, respectively; P obc The on-board charging power is defined as follows: A1 and B1 are the first and second power coefficients, respectively, both of which are calibrated values. Among them, A1 < 1, preferably A1 = 0.6-0.8, and B1 < 0.1, preferably B1 = 0.02-0.06.

[0060] Among them, the third heating power P heat_3 This refers to the dynamically adjusted power output value during the preheating phase. Specifically, this is achieved by sending a PWM signal from the vehicle controller to the heating film actuator. The power value setting must meet the safety verification requirements of real-time collected battery temperature, voltage, and internal resistance parameters. This feature is used to establish sufficient temperature reserves before the SOC critical point arrives, shortening the time required to reach the target temperature rise.

[0061] Specifically, when the battery management system detects that the current SOC value is approaching the critical point requiring preheating, the heating control module immediately switches the power output to the preset heating power. At this time, the battery temperature rises to the target temperature T at a certain rate. i+1 This process is achieved through real-time monitoring of the temperature rise curve and the dynamic balance of the heat dissipation model. This invention dynamically adjusts the heating power to complete the temperature increase before the SOC critical value is reached, ensuring that the charging power is not lower than the on-board charging power level when the SOC rises to the critical value.

[0062] Through the above technical solution, the present invention effectively avoids the problem of power depletion caused by continuous discharge in the low SOC segment. The battery temperature quickly reaches the working range under the prediction mechanism, so that the charging power can be restored to the normal level in time, ensuring the safety and efficiency of the charging process.

[0063] This invention further proposes a low-temperature charging coordinated control system for electric vehicles that implements the above control method, comprising: A permissible charging power determination module is used to determine the permissible charging power of the battery based on the battery SOC and battery temperature. The charging module determines the difference between the battery's allowable charging power and the vehicle's charging power. If the allowable charging power is greater than or equal to the vehicle's charging power, the battery is charged only. If the allowable charging power is less than the vehicle's charging power, a gradient heating signal is sent to the predictive gradient heating module while the battery is being charged. The predictive gradient heating module is used to heat the battery until the battery temperature reaches the reference target temperature when a gradient heating signal is received. The predictive gradient heating method controls the battery heating power to balance the heating and heat dissipation of the battery until the battery SOC reaches 100%.

[0064] The allowable charging power determination module dynamically adjusts the upper limit of charging power by acquiring real-time battery SOC and temperature data. Specifically, this can be implemented using a SOC-temperature-allowable charging power MAP table lookup method, matching the maximum safe charging power under the current state. The charging judgment module is a logic unit that switches the charging mode based on the comparison between the allowable charging power and the on-board charging power. This can be implemented using a threshold comparator and a signal trigger, initiating a gradient heating process when the allowable power is insufficient. The predictive gradient heating module is a heating control unit that combines temperature rise prediction and heat dissipation compensation. This can be implemented using a phased temperature rise target setting and an SOC point prediction algorithm, maintaining thermal balance by gradually increasing the heating power and matching heat dissipation requirements. The functions of each module have been described in detail in the control methods above and will not be repeated here.

[0065] Specifically, the allowable charging power determination module continuously monitors the battery's SOC and temperature, and obtains the current allowable charging power by looking up a table. The determination module compares the allowable power with the vehicle's onboard power; if the allowable power is insufficient, it triggers a gradient heating signal. Upon receiving the signal, the predictive gradient heating module first heats the battery to a baseline target temperature, and then enters the gradient heating phase: controlling the battery temperature to be maintained at T... i This involves predicting whether a preheating process is needed for subsequent State of Charge (SOC) points. If a SOC point requires preheating, the heating power is increased to raise the temperature to T when the SOC reaches that point. i+1 After updating the temperature rise target, the temperature is maintained; if it does not exist, the State of Charge (SOC) is continuously monitored until fully charged. This process ensures that the heating power is always dynamically matched with the charging progress through the coordinated control of staged temperature rise and SOC prediction.

[0066] This invention eliminates the lag effect by adjusting heating power in advance through phased temperature rise targets and SOC point prediction; it also reduces the impact of ambient temperature fluctuations on energy consumption by establishing a heat dissipation model to calculate the heating power and heat dissipation balance point in real time. This invention achieves dynamic coordinated control of charging and heating during low-temperature charging, effectively preventing battery depletion caused by excessive heating power in the low SOC stage. A predictive gradient heating strategy eliminates the response delay of traditional temperature control, avoiding energy waste caused by temperature overshoot. Combined with the dynamic compensation mechanism of the ambient heat dissipation model, it significantly reduces heating energy consumption in cold regions, improving low-temperature charging efficiency and safety.

[0067] A computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the electric vehicle low-temperature charging coordinated control method as described above.

[0068] A storage medium storing a computer program that, when executed by a processor, implements the steps of the electric vehicle low-temperature charging coordinated control method described above.

[0069] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0070] Those skilled in the art will also understand that the various illustrative logic blocks, units, and steps listed in the embodiments of the present invention can be implemented by electronic hardware, computer software, or a combination of both. To clearly demonstrate the substitutability of hardware and software, the functions of the various illustrative components, units, and steps described above have been generally described. Whether such functionality is implemented through hardware or software depends on the specific application and the overall system design requirements. Those skilled in the art can implement the described functions using various methods for each specific application, but such implementation should not be construed as exceeding the scope of protection of the embodiments of the present invention.

[0071] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Contents not described in detail in this specification belong to prior art known to those skilled in the art.

Claims

1. A method for coordinated control of low-temperature charging of electric vehicles, characterized in that: Determine the allowable charging power of the battery based on battery SOC and battery temperature; If the battery's allowable charging power is greater than or equal to the vehicle's charging power, then the battery will not be heated, the battery will continue to be charged, and the process will return to the step of determining the battery's allowable charging power based on the battery's SOC and battery temperature. If the battery's allowable charging power is less than the vehicle's charging power, the battery is heated until the battery temperature reaches the baseline target temperature. A predictive gradient heating method is used to control the battery heating power to balance the battery's heating and heat dissipation until the battery's SOC reaches 100%.

2. The electric vehicle low-temperature charging coordinated control method according to claim 1, characterized in that: The allowable charging power of the battery is determined by looking up the SOC-Temperature-Allowable Charging Power MAP table based on the battery's SOC and temperature.

3. The electric vehicle low-temperature charging coordinated control method according to claim 1, characterized in that, The first heating power P for heating the battery heat_1 Determined based on the battery's state of charge (SOC): If SOC < SOC1, then P heat_1 =A1×P obc ; If SOC1 ≤ SOC < SOC2, then P heat_1 =P obc -B1×(SOC2-SOC)×P obc ; If SOC ≥ SOC², then P heat_1 The maximum power that allows the battery to heat up; Where SOC is the real-time battery SOC value; SOC1 and SOC2 are the set first and second SOC thresholds, respectively; P obc The on-board charging power is denoted by A1 and B1, which are the first and second power coefficients, respectively, where A1 < 1 and B1 < 0.

1.

4. The electric vehicle low-temperature charging coordinated control method according to claim 1, characterized in that, The process for determining the reference target temperature is as follows: Query the SOC-Temperature-Allowable Charging Power MAP table to determine all critical battery temperatures corresponding to the allowable charging power of the battery with the same on-board charging power, and use the minimum temperature value among all critical battery temperatures as the benchmark target temperature.

5. The electric vehicle low-temperature charging coordinated control method according to claim 1, characterized in that, The method of controlling the battery heating power using a predictive gradient heating approach to balance battery heating and heat dissipation includes: Controlling the battery temperature to maintain at T i ; Predict whether there is a state of charge (SOC) critical point that requires preheating of the battery; If present, after the battery's SOC reaches the critical SOC point, increase the battery heating power until the battery temperature reaches T. i+1 , will T i Updated to T i+1 To determine whether the battery's SOC has reached 100%; If not, then determine whether the battery SOC has reached 100%; If the battery's SOC has not reached 100%, the system will return to control the battery temperature to maintain at T. i Steps; Among them, T i This represents the preset target temperature for temperature rise, where i is the number of the target temperature, starting from 1. i+1 >T i .

6. The electric vehicle low-temperature charging coordinated control method according to claim 5, characterized in that, The battery temperature is maintained at T. i The second battery heating power P heat_2 Determined by the following formula: P heat_2 =hA×(T i -Tenv); Where hA is the battery heat dissipation coefficient; Tenv is the ambient temperature.

7. The electric vehicle low-temperature charging coordinated control method according to claim 5, characterized in that, The prediction of whether there is a SOC critical point that requires preheating of the battery includes: Based on battery SOC and T i Locate the SOC-Temperature-Allowable Charging Power MAP table and determine the temperature range in the MAP table at T. i If there is an allowable charging power lower than the vehicle charging power among all allowable charging powers corresponding to the battery SOC, then it is predicted that there is an SOC critical point that requires preheating of the battery; otherwise, it is predicted that there is no SOC critical point that requires preheating of the battery.

8. The electric vehicle low-temperature charging coordinated control method according to claim 5, characterized in that, If there is a SOC critical point that requires preheating of the battery, the SOC value of the SOC critical point is determined by the following formula: (SOC i -SOC 点 ) / v soc_i =(T i+1 -T i ) / V T ; Among them, SOC i To maintain the battery temperature at T i At that time, the battery's allowable power obtained from the table is less than the SOC value corresponding to the on-board charging power at that moment; SOC 点 v is the SOC value at the critical point of SOC. soc_i For battery temperature from T i Upgrade to T i+1 SOC change rate during the process; V T For battery SOC from SOC 点 Rise to SOC i The rate of temperature rise during the process.

9. The electric vehicle low-temperature charging coordinated control method according to claim 5, characterized in that: The third heating power P of the battery after increasing the battery heating power heat_3 Determined based on the battery's state of charge (SOC): If SOC < SOC1, then P heat_3 =A1×P obc ; If SOC1 ≤ SOC < SOC2, then P heat_3 =P obc -B1×(SOC2-SOC)×P obc ; If SOC ≥ SOC², then P heat_3 The maximum power that allows the battery to heat up; Where SOC is the real-time battery SOC value; SOC1 and SOC2 are the set first and second SOC thresholds, respectively; P obc The on-board charging power is denoted by A1 and B1, which are the first and second power coefficients, respectively, where A1 < 1 and B1 < 0.

1.

10. A low-temperature charging collaborative control system for electric vehicles, characterized in that, include: A permissible charging power determination module is used to determine the permissible charging power of the battery based on the battery SOC and battery temperature. The charging module determines the difference between the battery's allowable charging power and the vehicle's charging power. If the allowable charging power is greater than or equal to the vehicle's charging power, the battery is charged only. If the allowable charging power is less than the vehicle's charging power, a gradient heating signal is sent to the predictive gradient heating module while the battery is being charged. The predictive gradient heating module is used to heat the battery until the battery temperature reaches the reference target temperature when a gradient heating signal is received. The predictive gradient heating method controls the battery heating power to balance the heating and heat dissipation of the battery until the battery SOC reaches 100%.

11. A computer device, comprising a memory and a processor, characterized in that: The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the electric vehicle low-temperature charging cooperative control method as described in any one of claims 1 to 9.

12. A storage medium storing a computer program, characterized in that: When the computer program is executed by the processor, it implements the steps of the electric vehicle low-temperature charging cooperative control method as described in any one of claims 1 to 9.

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