Sodium-ion start-stop battery low-temperature starting and back-charge adaptive control method and system based on MCU-BMS cooperation

Abstract

The application relates to a sodium-ion start-stop battery low-temperature starting and self-adaptive control method and system based on MCU-BMS cooperation. The method comprises the following steps: collecting cell temperature, pole or shell temperature and environmental temperature to form a temperature feature set; collecting terminal voltage and current and calculating an equivalent internal resistance parameter; determining a starting capability window from the temperature feature set and the equivalent internal resistance parameter and controlling starting discharge, recording starting electric parameter features to generate a recharging boundary condition; combining the temperature feature set, the equivalent internal resistance parameter and the recharging boundary condition to generate a target recharging voltage and its change rate constraint and implementing recharging, and updating control parameters according to recharging execution results and battery state feedback. The system comprises a sodium-ion start-stop battery body, a temperature sensing component, an electric parameter collecting component, an MCU controller, a BMS and a recharging adjusting interface. The application can limit starting voltage collapse and current impact at low temperature, improve cold starting success rate, and simultaneously make the recharging voltage adaptively and smoothly adjusted with the internal resistance, and improve low-temperature recharging stability.

Description

Technical Field

[0001] This application relates to the field of sodium-ion start-stop batteries, and in particular to an adaptive control method and system for low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration. Background Technology

[0002] Vehicle start-stop batteries provide energy for engine starting, powering onboard electrical systems, and supporting frequent charging and discharging during start-stop operations. In low-temperature environments such as northern winters, vehicle starting demands are often concentrated in cold-start conditions, requiring the starter motor to have a high instantaneous power output capability. Existing start-stop batteries (including lead-acid batteries and some lithium-ion battery systems) typically exhibit increased internal resistance, decreased usable capacity, and intensified polarization under low-temperature conditions. This leads to a significant drop in terminal voltage at the moment of starting, resulting in problems such as insufficient starter motor speed, difficulty in engine ignition, or start-up failure, affecting the vehicle's availability and reliability in low-temperature environments.

[0003] Meanwhile, after the vehicle starts successfully, the power system (such as the generator or related power management unit) usually needs to recharge the start-stop battery to restore its state of charge. However, under low-temperature conditions, the battery's charging acceptance capability changes significantly with temperature and internal resistance: on the one hand, the increased internal resistance of the battery makes it easier for the terminal voltage to rise rapidly during charging, easily leading to "false voltage" phenomena; on the other hand, if the recharge voltage control strategy based on normal temperature or a fixed threshold is still used, it may result in insufficient charging due to setting the recharge voltage too low, or excessive polarization, frequent current limiting, recharge oscillation, etc., due to setting the recharge voltage too high, thereby affecting recharge efficiency, comfort, and system stability, and even adversely affecting battery life and safety.

[0004] In recent years, sodium-ion batteries have been applied in the field of start-stop batteries due to their resource availability, power characteristics, and adaptability under specific operating conditions. However, sodium-ion start-stop batteries also suffer from changes in internal resistance and polarization characteristics at low temperatures. Furthermore, the vehicle and battery sides are typically managed and protected by the vehicle controller, microcontroller, and battery management system, respectively. Without an effective coordination mechanism, issues such as disconnection between start-up and recharge control, difficulty in updating control parameters in a timely manner based on the actual battery state, fluctuations during recharge, and frequent triggering of protection strategies can easily occur. Therefore, how to simultaneously ensure the start-up power supply capability of sodium-ion start-stop batteries under low-temperature conditions, and enable the power system to adaptively adjust the voltage during the recharge process based on battery temperature and internal resistance, has become a pressing technical problem to be solved in this field. Summary of the Invention

[0005] The purpose of this application is to solve the problems of difficulty in low-temperature start-up and difficulty in adapting low-temperature recharge voltage.

[0006] According to one aspect of this application, a method for adaptive control of low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration is provided, comprising: S10. Collect the cell temperature, terminal or casing temperature and ambient temperature of the sodium-ion start-stop battery to generate a temperature feature set for low-temperature control. S20. Collect the terminal voltage and current information of the sodium-ion start-stop battery, and calculate the equivalent internal resistance parameter in combination with the temperature feature set; S30. Determine the start-up capability window based on the temperature feature set and the equivalent internal resistance parameter, and control the start-up discharge of the sodium-ion start-stop battery within the start-up capability window; record the voltage response characteristics and current characteristics during the start-up phase, and generate recharge boundary conditions. S40. Based on the temperature feature set, the equivalent internal resistance parameter, and the recharge boundary condition, generate a target recharge voltage and its rate of change constraint, so that the target recharge voltage is adaptively adjusted as the equivalent internal resistance parameter changes. S50. The sodium-ion start-stop battery is recharged according to the target recharge voltage and its rate of change constraint, and the abnormal changes in terminal voltage during the recharge process are suppressed by adjusting the target recharge voltage and / or tightening the rate of change constraint. S60. Receive the recharge execution result and battery status feedback, and update the temperature feature set, the equivalent internal resistance parameter, and / or the target recharge voltage and its rate of change constraint accordingly.

[0007] Preferably, the step S10 generates a temperature feature set including: The cell temperature and the terminal or casing temperature are sampled at least twice redundantly and a consistency check is performed. The consistency check includes at least drift judgment, jump judgment or out-of-bounds judgment. When redundancy inconsistency is determined, the alternative temperature value after consistency verification is used to participate in the generation of temperature feature set, and the corresponding derating or protection flag is output.

[0008] Preferably, the temperature feature set includes: Low temperature rating and temperature difference characterization, wherein the low temperature rating is obtained by mapping the cell temperature to the ambient temperature, and the temperature difference characterization is calculated by the difference between the cell temperature and the terminal or casing temperature and / or the difference between the cell temperature and the ambient temperature; The low temperature level is used in S30 to select the start-up capability window parameter set corresponding to the low temperature level, and in S40 to select the initial recharge voltage parameter set corresponding to the low temperature level.

[0009] Preferably, the calculation of the equivalent internal resistance parameter in step S20 includes: A short-time current disturbance is applied to a sodium-ion start-stop battery and the terminal voltage response is collected. The equivalent internal resistance parameter is calculated based on the short-time current disturbance and the terminal voltage response. The validity of the equivalent internal resistance parameters is determined based on the consistency of the equivalent internal resistance parameters obtained from at least two short-time current disturbances and / or the fitting residual of the terminal voltage response. When the equivalent internal resistance parameter is determined to be invalid, a short-time current disturbance is reapplied and recalculated, or the equivalent internal resistance parameter of the previous control cycle is used in subsequent S30 and S40.

[0010] Preferably, S30 determining the startup capability window includes: The upper limit of the allowable start-up discharge current and / or the lower limit of the allowable start-up terminal voltage are determined based on the temperature feature set and the equivalent internal resistance parameter, and the start-up capability window is formed by the upper limit of the start-up discharge current and / or the lower limit of the start-up terminal voltage. During the startup control process, when the startup terminal voltage is detected to be lower than the startup terminal voltage lower limit and / or the startup discharge current reaches the startup discharge current upper limit, the startup discharge control quantity is adjusted to make the startup process meet the startup capability window constraint.

[0011] Preferably, the step S30 of generating the recharge boundary conditions includes: The voltage response characteristics and current characteristics during the startup phase are statistically analyzed or extracted to obtain one or more of the following: recharge initiation voltage limit, recharge initiation current limit, and recharge voltage rise rate limit, which constitute the recharge boundary conditions. When generating the target recharge voltage and its rate of change constraint, S40 uses the recharge boundary condition as the initial recharge constraint input.

[0012] Preferably, the generation of the target recharge voltage and its rate of change constraint in S40 includes: The target recharge voltage is updated according to a preset control cycle, and an upper limit is set for the difference between the target recharge voltages of two adjacent control cycles to form the rate of change constraint. The initial value of the target recharge voltage is determined by the temperature feature set and the equivalent internal resistance parameter, and is subject to the recharge boundary conditions during the update process.

[0013] Preferably, the process of S50 suppressing abnormal changes in terminal voltage during the recharge process includes: When the terminal voltage rise rate exceeds the preset threshold during the recharge process and / or the terminal voltage rises abnormally without an increase in the recharge current, and the temperature feature set is characterized as a low temperature level, the low temperature polarization criterion is determined to be met, thereby reducing the target recharge voltage and / or tightening the rate of change constraint of the target recharge voltage. When the low temperature level characterized by the temperature feature set reaches the preset threshold and the equivalent internal resistance parameter is higher than the preset threshold, an intermittent pulse reheating and recharging strategy is adopted to adjust the recharge voltage in a pulse manner to promote temperature rise. When the cell temperature rises to a preset threshold and / or the equivalent internal resistance parameter decreases to a preset threshold, the target recharge voltage and its rate of change constraint are relaxed as a release condition, and continuous recharge is resumed.

[0014] The present invention also provides an adaptive control system for low-temperature start-up and recharge of sodium-ion start-stop battery based on MCU-BMS collaboration, which is applied to the adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop battery based on MCU-BMS collaboration as described above, and includes: sodium-ion start-stop battery body, temperature sensing component, electrical parameter acquisition component, MCU controller, BMS and recharge adjustment interface. The sodium-ion start-stop battery body includes a cell, terminals or a casing; the temperature sensing component is respectively arranged in the cell, terminals or casing and the environment and outputs a temperature signal; the electrical parameter acquisition component is electrically connected to the terminals of the sodium-ion start-stop battery body and outputs terminal voltage signal and current signal. The MCU controller is electrically or communicatively connected to the temperature sensing component and the electrical parameter acquisition component to receive the temperature signal, terminal voltage signal and current signal, and is connected to the vehicle charging side through the recharge adjustment interface to output the recharge voltage setting signal; the MCU controller is also connected to the start-up circuit of the sodium-ion start-stop battery body to output the start-up discharge control signal. The BMS is communicatively connected to the MCU controller. The BMS outputs a battery status feedback signal to the MCU controller, and the MCU controller sends back the start-up phase electrical parameter characteristic signal and / or recharge execution result signal to the BMS.

[0015] Preferably, a bidirectional communication interface is provided between the MCU controller and the BMS. The bidirectional communication interface includes: a first bus interface circuit electrically connected to the communication port of the MCU controller, a second bus interface circuit electrically connected to the communication port of the BMS, and a bus connection line connecting the first bus interface circuit and the second bus interface circuit. The first bus interface circuit and / or the second bus interface circuit include at least a bus transceiver, a terminal matching unit, and a connector unit. The terminal matching unit is electrically connected to the bus connection line, and the connector unit is used to detachably connect the bus connection line to the MCU controller and the BMS.

[0016] This application offers the following advantages: It establishes a temperature feature set by analyzing the cell temperature, terminal or casing temperature, and ambient temperature of the sodium-ion start-stop battery. Combined with terminal voltage and current calculations of equivalent internal resistance parameters, it establishes a unified state characterization basis for startup and recharge. Based on this, it determines the startup capability window and constrains the startup discharge, suppressing transient voltage drops at low temperatures and improving cold start success rate and startup stability. During the startup phase, it further records voltage response and current characteristics to form recharge boundary conditions, generating a target recharge voltage and its rate of change constraint. This allows the recharge voltage to adaptively adjust with changes in equivalent internal resistance, avoiding insufficient recharge due to increased internal resistance at low temperatures or misjudgments, frequent current limiting, and recharge oscillations caused by artificially high terminal voltage, thus improving recharge efficiency and controllability. During recharge, it suppresses abnormal changes in terminal voltage and combines feedback to update temperature characteristics, equivalent internal resistance, and recharge control parameters, forming a closed-loop self-correction mechanism that enhances robustness and consistency under different low-temperature operating conditions and load fluctuations. In terms of the system, through the signal connection and interaction of temperature sensing components, electrical parameter acquisition components, MCU controller, BMS and recharge adjustment interface, a closed-loop link is realized, which is battery status perception - start-up control - recharge voltage setting - recharge execution - feedback update. This makes the vehicle-side recharge adjustment and battery-side status management coordinated and consistent, improving the vehicle availability and battery safety in low-temperature environments. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a logic block diagram of the adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration, as described in one embodiment of this application. Detailed Implementation

[0019] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0020] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] Please refer to Figure 1 One embodiment of this application provides an adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration, including: S10. Collect the cell temperature, terminal or casing temperature, and ambient temperature of the sodium-ion start-stop battery to generate a temperature feature set for low-temperature control. It should be noted that the temperature feature set is not merely a simple collection of temperature sample values, but rather a control input set after organizing and preprocessing multi-point temperature information for the purpose of low-temperature control. Specifically, the cell temperature is collected to characterize the thermal state of the battery body; the terminal or casing temperature is collected to characterize the thermal state of the end conductive path and the influence of external heat transfer; and the ambient temperature is collected to characterize external cooling conditions and temperature change trends. To improve the reliability of low-temperature determination, at least two temperature information streams can be redundantly checked and anomaly eliminated to avoid misjudgments caused by sensor drift or local temperature differences. Based on this, the temperature data is normalized, graded, or combined to form a temperature feature set that can be used for control decisions, providing stable input for subsequent equivalent internal resistance estimation, start-up capability assessment, and recharge constraint generation.

[0023] S20. Collect the terminal voltage and current information of the sodium-ion start-stop battery, and calculate the equivalent internal resistance parameter by combining it with the temperature feature set. In this step, it should be noted that the equivalent internal resistance parameter reflects the conductivity and polarization degree of the sodium-ion start-stop battery under low-temperature conditions, serving as a crucial bridge connecting "temperature state" and "voltage control strategy." The terminal voltage and current information can be obtained from real-time sampling of the electrical parameter acquisition circuit. Combining it with the temperature feature set allows for adaptation to the increase in internal resistance and polarization characteristics at low temperatures. The calculation of the equivalent internal resistance parameter can use a short-time perturbation method to obtain the voltage response, thereby obtaining an internal resistance estimate representative of the current operating condition without affecting the overall vehicle power supply stability. The validity of the calculation process can be verified, for example, by checking the consistency of multiple perturbations or the fitting error of the response curve to determine whether the estimate is usable, thus avoiding deviations introduced by factors such as abnormal sampling and sudden changes in contact resistance.

[0024] S30. Determine the starting capability window based on the temperature feature set and equivalent internal resistance parameters, and control the starting discharge of the sodium-ion start-stop battery within the starting capability window. Record the voltage response characteristics and current characteristics during the starting phase to generate recharge boundary conditions. In this step, it should be noted that the starting capability window is used to transform "whether it can start reliably at low temperatures" into an executable constraint boundary, ensuring that the starting control is neither overly conservative nor excessively drained. The starting capability window can be jointly determined by the temperature feature set and equivalent internal resistance parameters, and its meaning can be understood as: the allowable starting discharge intensity and its duration range under the current low temperature and internal resistance conditions. Starting control is performed within the window, which can limit excessive voltage drop and current surge while ensuring the starter's requirements. Simultaneously, the voltage response characteristics and current characteristics during the starting phase are recorded and organized into recharge boundary conditions. These boundary conditions characterize "the voltage / current response state of the battery immediately after starting and its sensitivity to the recharge voltage increase," providing initial constraints for subsequent recharge strategies and avoiding control oscillations or misjudgments caused by immediate recharge after starting.

[0025] In this step, it should be noted that, in addition to the target recharge voltage and its rate of change constraint, the recharge control parameters generated by S40 may also include a recharge current limiting threshold and / or a recharge voltage limiting threshold. These thresholds can be configured in segments according to the low-temperature level to match the charging acceptance capability of the sodium-ion start-stop battery in different temperature ranges. Specifically, the low-temperature levels in the temperature feature set can be divided into a first low-temperature range, a second range, and a third range, and different sets of recharge constraint parameters can be selected for different ranges. For example, when the cell temperature is in the first low-temperature range (e.g., below -10℃), the upper limit of the recharge current is set to the first threshold (e.g., 3A), and the rate of increase of the recharge voltage is correspondingly tightened. When the cell temperature is in the second range (e.g., from -10℃ to 10℃), the upper limit of the recharge current is set to the second threshold (e.g., 14A), and a higher rate of increase of the recharge voltage is allowed. When the cell temperature is in the third range (e.g., above 10℃), the upper limit of the recharge current is released or set to a higher upper limit, thereby gradually transitioning the recharge strategy from a conservative approach at low temperatures to a more open approach at room temperature. The above threshold values ​​are only examples. In actual applications, they can be adjusted according to battery specifications, vehicle generator capacity, and calibration results. At the same time, the segmented current limiting threshold can be generated in conjunction with the target recharge voltage and its rate of change constraint, so that the recharge process can achieve smoother adaptive adjustment under multiple constraints of "voltage setting - current constraint - rate of change limit", thereby more effectively suppressing the terminal voltage high caused by low temperature polarization and recharge oscillation.

[0026] S50. Recharge the sodium-ion start-stop battery according to the target recharge voltage and its rate of change constraint, and suppress abnormal changes in terminal voltage during the recharge process by adjusting the target recharge voltage and / or tightening the rate of change constraint. In this step, it should be noted that the recharge execution follows a combined control approach of "target voltage + rate of change constraint": on the one hand, the voltage is set or adjusted according to the target recharge voltage; on the other hand, voltage changes are constrained to reduce terminal voltage spikes caused by low-temperature polarization. Suppression of abnormal terminal voltage changes can be manifested as follows: when the terminal voltage shows an abnormal upward trend that does not conform to the current recharge intensity, the abnormality is suppressed by reducing the target recharge voltage and / or further tightening the rate of change constraint, avoiding misjudging the voltage rise caused by polarization as full charging or triggering frequent protection. This process can be coordinated with the real-time status of the vehicle-side generator / power management to ensure that the recharge adjustment meets both the vehicle's power supply boundaries and the battery's acceptable low-temperature charging capability.

[0027] S60. Receive the recharge execution result and battery status feedback, and update the temperature feature set, equivalent internal resistance parameter, and / or target recharge voltage and its rate of change constraint accordingly. In this step, it should be noted that the recharge execution result and battery status feedback constitute the input source for closed-loop self-calibration. The recharge execution result can reflect the deviation between the target recharge voltage setting and the actual terminal voltage response, the effectiveness of the rate of change constraint, and whether abnormal trends occur during the recharge process; the battery status feedback can reflect battery temperature evolution, internal resistance changes, and state changes after recharge. Based on the above feedback, the temperature feature set, equivalent internal resistance parameter, and target recharge voltage and rate of change constraint are updated, enabling the control parameters to gradually converge with changes in ambient temperature, differences in startup events, and differences in recharge response, forming an interpretable and iterative low-temperature startup and recharge collaborative closed loop.

[0028] The technical solution implemented in this embodiment can use multi-point temperature characteristics and equivalent internal resistance as a unified state characterization basis in low-temperature environments. First, it constrains the discharge by using a start-up capability window, reducing voltage sag and high-current surges during startup, thereby improving the cold-start success rate and startup stability of sodium-ion start-stop batteries. After startup, it utilizes startup electrical parameters to form recharge boundary conditions, allowing recharge control to seamlessly integrate with startup conditions. Furthermore, it generates target recharge voltage and rate of change constraints based on temperature characteristics, equivalent internal resistance, and recharge boundary conditions, enabling the recharge voltage to adaptively and smoothly adjust with changes in internal resistance. This suppresses artificially high terminal voltage and recharge oscillations caused by low-temperature polarization, reduces frequent current limiting and misjudgments, and improves low-temperature recharge efficiency and consistency. Simultaneously, it continuously updates control parameters through recharge execution results and battery status feedback, enhancing robustness and repeatability under different low-temperature levels, different load fluctuations, and different individual differences, thus addressing both the core requirements of low-temperature startability and low-temperature rechargeability.

[0029] Furthermore, the temperature feature set generated by S10 includes: The cell temperature and the terminal or casing temperature should be sampled at least twice redundantly and a consistency check should be performed. The consistency check should include at least drift detection, jump detection or out-of-bounds detection.

[0030] When redundancy inconsistency is determined, the alternative temperature value after consistency verification is used to participate in the generation of temperature feature set, and the corresponding derating or protection flag is output.

[0031] In this embodiment, it should be noted that the "dual-point redundant sampling" is not limited to simply adding a temperature sensor. Rather, it addresses the characteristics of temperature measurement in low-temperature start-stop scenarios, which are easily affected by installation location, thermal coupling differences, and sensor drift. It configures at least two independent sampling channels for cell temperature and electrode or casing temperature, or uses two sampling paths for cross-validation at the same location to improve the reliability of temperature input. During consistency verification, two temperature curves of the same measured object can be compared: drift judgment is used to identify systematic errors caused by long-term slow shifts; jump judgment is used to identify instantaneous changes, poor contact, or sampling anomalies; and out-of-bounds judgment is used to identify abnormal values ​​exceeding reasonable physical ranges. These judgments can be performed in a rolling time window, ensuring that anomaly identification is not overly sensitive to short-term noise while quickly detecting anomalies during critical start-up and recharge phases, thereby preventing erroneous temperatures from entering subsequent equivalent internal resistance estimation, start-up capability assessment, and recharge constraint generation processes.

[0032] When redundancy inconsistency is detected, the "alternative temperature value" is not arbitrary but selected and shaped based on the verification results of redundant channels. For example, the temperature of the channel that has passed the boundary judgment and shows a continuous trend is selected as the alternative value, or when both temperatures are within the boundary but there is a deviation, the more conservative temperature is used as the alternative value to participate in the temperature feature set generation, so that the control strategy converges in the direction with higher low-temperature risk. At the same time, in order to make the system traceable and controllable, the output derating or protection flag can be used as a strategy input to prompt subsequent discharge and recharge regulation to enter a more conservative control mode, such as limiting the upper limit of the start-up capability window, tightening the rate of change of the recharge voltage, or delaying the recharge release, thereby explicitly incorporating the "measurement unreliable" state into the control closed loop, rather than just recording the fault at the bottom level.

[0033] The technical solution implemented in this embodiment can significantly improve the stability and reliability of temperature input under low-temperature start-stop conditions, reduce the risk of misjudgment caused by single-point temperature drift, instantaneous jumps, or out-of-range anomalies, and make the temperature feature set more consistent with the actual thermal state of the battery. This reduces the deviation in equivalent internal resistance estimation, start-up capability window setting, and recharge voltage adaptive adjustment from the source. Furthermore, in cases of redundancy inconsistency, abnormal states are exposed in advance and linked for control by replacing temperature values ​​and derating / protection flags. This allows the system to automatically switch to a conservative strategy in the event of sensor or thermal coupling anomalies, reducing phenomena such as low-temperature start-up failures, recharge oscillations, and frequent protection triggers, thereby improving the robustness and safety of vehicle start-up and recharge control in low-temperature scenarios.

[0034] Furthermore, the temperature feature set includes: Low temperature rating and temperature difference characterization: The low temperature rating is obtained by mapping the cell temperature to the ambient temperature, and the temperature difference characterization is calculated by the difference between the cell temperature and the terminal or casing temperature and / or the difference between the cell temperature and the ambient temperature.

[0035] In S30, the low temperature level is used to select the start-up capability window parameter set corresponding to the low temperature level, and in S40, it is used to select the initial parameter set of the recharge voltage corresponding to the low temperature level.

[0036] In this embodiment, it should be noted that the temperature feature set does not simply use the collected multi-point temperature data directly for control. Instead, it uses "low temperature level" and "temperature difference characterization" to structurally express the key influencing factors of low-temperature conditions, enabling subsequent startup and recharge control to quickly switch to the matching parameter set under different low-temperature states. Specifically, the low-temperature level is obtained by mapping the cell temperature to the ambient temperature. The cell temperature reflects the actual thermal state of the battery, while the ambient temperature reflects the external cooling intensity and the duration of the low temperature. The combination of the two can more accurately distinguish between different scenarios such as "the battery has been fully cooled" and "the ambient temperature is low but the battery still has residual heat." The mapping can adopt a hierarchical or interval classification method to convert continuous temperature input into a finite number of manageable low-temperature levels, thereby facilitating the configuration, calibration, and online selection of strategy parameters.

[0037] Temperature difference characterization reflects the differences in heat distribution and heat transfer between the battery's interior and terminals, as well as between the battery and the external environment. The difference between the cell temperature and the terminal or casing temperature indicates the degree to which the terminal conductive path is affected by cooling and the difference in heat conduction. The difference between the cell temperature and the ambient temperature reflects the overall temperature gradient between the battery and the external environment and its recovery potential. By incorporating these differences into the temperature feature set, the control strategy can focus not only on "how low the current temperature is," but also on "whether the temperature distribution is uniform and whether the recovery trend is feasible," thus providing more interpretable input for startup capability assessment and recharge voltage setting.

[0038] The roles of low-temperature rating and temperature difference characterization in the control link are explicitly tied to parameter set selection: During startup, the low-temperature rating is used to select the startup capability window parameter set corresponding to that low-temperature rating. This allows startup control to adopt a more conservative window boundary for operating conditions with higher internal resistance and deeper low temperatures, reducing the risk of transient voltage drops and high-current surges during startup. During recharge, the low-temperature rating is used to select the initial recharge voltage parameter set corresponding to that low-temperature rating. This ensures that the recharge voltage starts from an initial value matched to the low-temperature state, avoiding falsely high terminal voltages, misjudgments, or oscillations caused by directly using initial values ​​at room temperature under low-temperature conditions. Temperature difference characterization can serve as a correction basis within the aforementioned parameter set, distinguishing different thermal distribution scenarios within the same low-temperature rating, making parameter selection more refined while maintaining a clear structure.

[0039] The technical solution implemented in this embodiment can transform multi-point temperature information into calibrable and manageable low-temperature levels and temperature difference characteristics, providing a unified and clear entry point for the selection of control parameters for low-temperature start-up and low-temperature recharge, thereby reducing strategy inconsistencies caused by temperature input fluctuations or scenario differences. By selecting the parameter set of the start-up capability window driven by the low-temperature level, the start-up discharge boundary can be matched more stably under different cold-start conditions, improving the start-up success rate and power supply stability during the start-up process. By selecting the initial parameter set of the recharge voltage driven by the low-temperature level and correcting it in conjunction with the thermal distribution differences reflected by the temperature difference characterization, the recharge control under low-temperature conditions can be smoother and more in line with the actual acceptable capacity of the battery, reducing misjudgments and oscillations caused by artificially high recharge voltages, and improving recharge efficiency and overall robustness in low-temperature scenarios.

[0040] Furthermore, the equivalent internal resistance parameters calculated for S20 include: A short-time current disturbance is applied to the sodium-ion start-stop battery and the terminal voltage response is collected. The equivalent internal resistance parameter is calculated based on the short-time current disturbance and the terminal voltage response.

[0041] The validity of the equivalent internal resistance parameters is determined based on the consistency of the equivalent internal resistance parameters obtained from at least two short-time current disturbances and / or the fitting residuals of the terminal voltage response.

[0042] When the equivalent internal resistance parameter is determined to be invalid, a short-time current disturbance is reapplied and the calculation is recalculated, or the equivalent internal resistance parameter of the previous control cycle is used in subsequent S30 and S40.

[0043] In this embodiment, it should be noted that the equivalent internal resistance parameter is used to characterize the conductivity and polarization of the sodium-ion start-stop battery under low-temperature conditions, which directly affects the assessment of output capability during the start-up phase and the judgment of chargeability during the recharge phase. To obtain an equivalent internal resistance parameter that reflects the current operating conditions, this embodiment adopts a short-time current perturbation method: without affecting the stability of the vehicle's power supply, the battery current undergoes controlled changes, and the response process of the terminal voltage is simultaneously collected. By establishing a correspondence between the current change caused by the short-time current perturbation and the terminal voltage change, an equivalent internal resistance parameter matching the current temperature state can be obtained, thereby avoiding the deviation caused by relying solely on static voltage or a single sampling. This is especially suitable for operating conditions where the internal resistance rises rapidly and polarization is significant at low temperatures.

[0044] To improve the reliability of the equivalent internal resistance parameter, this embodiment introduces an effectiveness determination mechanism. This mechanism is based on at least two types of information: first, "consistency of multiple disturbances," meaning that at least two short-time current disturbance calculations are performed within adjacent or the same control cycle. If the deviation of the equivalent internal resistance parameter obtained from the two calculations is within the allowable range, the estimation result is considered stable. Second, "response fitting residual," which involves matching the terminal voltage response curve with a preset response model or fitting relationship. When the residual exceeds a preset threshold, it is determined that the response may be affected by noise, sampling anomalies, or changes in connection status, thereby reducing its usability. Through the above determination, "usable internal resistance estimates" can be distinguished from "abnormal or unstable internal resistance estimates," avoiding the direct input of abnormal estimation results into subsequent control during critical low-temperature stages, which could lead to strategy misadjustment.

[0045] When the equivalent internal resistance parameter is determined to be invalid, this embodiment provides two processing paths to ensure the continuity of the control link: one is to reapply a short-time current disturbance and recalculate to obtain an updated equivalent internal resistance parameter; the other is to use the equivalent internal resistance parameter of the previous control cycle as a substitute input in subsequent S30 and S40 when immediate recalculation is not possible or recalculation is still unstable. By adopting the "recalculation priority, substitute fallback" approach, robustness can be improved while ensuring real-time performance, and abrupt changes in the calculation of the startup capability window or target recharge voltage due to individual disturbance failures can be avoided.

[0046] The technical solution implemented in this embodiment can obtain equivalent internal resistance parameters highly correlated with the current operating conditions through short-term disturbances in low-temperature environments, providing a more accurate state basis for capability assessment during startup and adaptive voltage adjustment during recharge. Simultaneously, by determining the validity of multiple disturbance consistency and response fitting residuals, the impact of sampling noise, connection status fluctuations, or transient disturbance anomalies on internal resistance estimation can be suppressed, reducing the transmission of internal resistance estimation errors to subsequent control links and lowering the risk of misadjustment in startup and recharge control. When estimation is invalid, recalculation or using the result from the previous cycle as a fallback ensures the continuity of control parameters and avoids strategy jumps, thereby improving the stability and reliability of the low-temperature startup and recharge process.

[0047] Furthermore, the S30 determines the startup capability window to include: The upper limit of the allowable starting discharge current and / or the lower limit of the allowable starting terminal voltage are determined based on the temperature characteristic set and the equivalent internal resistance parameter, and the starting capability window is formed by the upper limit of the starting discharge current and / or the lower limit of the starting terminal voltage.

[0048] During the startup control process, when the startup terminal voltage is detected to be lower than the lower limit of the startup terminal voltage and / or the startup discharge current reaches the upper limit of the startup discharge current, the startup discharge control quantity is adjusted to ensure that the startup process meets the startup capability window constraint.

[0049] In this embodiment, it should be noted that the "start-up capability window" is used to convert the output capability of the sodium-ion start-stop battery under low-temperature conditions into an executable boundary constraint, making the start-up discharge control data-driven and adaptively adjustable under different low-temperature levels and internal resistance variations. The start-up capability window consists of an upper limit for the allowable start-up discharge current and / or a lower limit for the allowable start-up terminal voltage. The upper limit for the start-up discharge current is used to limit the current surge during start-up, and the lower limit for the start-up terminal voltage is used to ensure that the supply voltage of the starter motor and key on-board control devices is not lower than the minimum operating voltage. The upper limit for the allowable start-up discharge current and the lower limit for the start-up terminal voltage are not fixed constants, but are determined based on a temperature characteristic set and an equivalent internal resistance parameter: the temperature characteristic set reflects the low-temperature level and thermal state, and the equivalent internal resistance parameter reflects the current conductivity and polarization degree. Both are used together to evaluate the current intensity and voltage drop range that can be withstood during the start-up phase, thereby obtaining a window boundary that matches the current operating conditions.

[0050] The startup control process is dynamically adjusted within the constraints of this window. When the startup terminal voltage is detected to be lower than the lower limit, it indicates that the voltage drop caused by the current startup discharge has approached or exceeded the allowable range. At this time, the startup discharge control quantity is adjusted to bring the terminal voltage back to the allowable range. When the startup discharge current is detected to reach the upper limit, it indicates that the startup current surge has approached or reached the upper limit threshold. At this time, the startup discharge control quantity is adjusted to limit the current from continuing to rise. The adjustment can adopt a gradual convergence method, so that the startup process meets the starter requirements while avoiding voltage collapse and excessive current surge caused by increased internal resistance at low temperatures, and provides a stable electrical parameter basis for subsequent startup characteristic recording and recharge boundary condition generation.

[0051] The technical solution implemented in this embodiment can constrain the start-up discharge in low-temperature environments through a dual-boundary approach of "upper current limit + lower voltage limit". This allows the start-up control to no longer rely on a single threshold or empirical setting, but to dynamically match the start-up intensity according to the temperature and internal resistance state. This reduces the risk of insufficient starter speed and controller power failure caused by excessive voltage drop during start-up, and suppresses connection heating and increased polarization caused by large current surges. At the same time, through dynamic adjustment at the window boundary trigger, it can reduce fluctuations and instability in the start-up process, improve the success rate of cold starts and the power supply stability during the start-up process, and provide a more controllable initial state for the subsequent recharge phase.

[0052] Furthermore, the S30 generates the recharge boundary conditions, including: By statistically analyzing or extracting the voltage and current characteristics during the startup phase, one or more of the following can be obtained: recharge initiation voltage limit, recharge initiation current limit, and recharge voltage rise rate limit, which constitute the recharge boundary conditions.

[0053] When generating the target recharge voltage and its rate of change constraints, S40 uses the recharge boundary conditions as the initial recharge constraint input.

[0054] In this embodiment, it should be noted that the startup phase and the recharge phase are continuous in time and strongly correlated in electrochemical state: startup discharge will cause phenomena such as rapid voltage drop, intensified polarization, and short-term increase in equivalent internal resistance. If the recharge voltage is rapidly increased immediately after startup according to the conventional recharge strategy, it is easy to cause "artificially high" voltage, frequent current limiting, or recharge oscillation. Therefore, in this embodiment, not only startup discharge control is completed in S30, but also the voltage response characteristics and current characteristics of the startup phase are statistically analyzed or extracted to form recharge boundary conditions that can constrain the initial stage of recharge, so as to achieve strategy inheritance and smooth connection between startup and recharge.

[0055] The "statistics or extraction" can be performed on key segments of the startup process, such as the peak range of the startup current, the vicinity of the lowest point of the terminal voltage, and the recovery phase after startup, thereby obtaining indicators reflecting the startup stress level and recovery capability. Based on the above indicators, one or more of the following can be constructed: a recharge initiation voltage limit, a recharge initiation current limit, and a recharge voltage rise rate limit: the recharge initiation voltage limit is used to define the starting point of the initial recharge voltage setting to avoid starting with an excessively high voltage and causing artificially high terminal voltage; the recharge initiation current limit is used to constrain the acceptable current of the battery before it has recovered after startup to avoid recharge current surges; the recharge voltage rise rate limit is used to control the rate at which the recharge voltage rises, allowing the recharge to gradually transition from a startup stress state to a stable recharge state. These limits are not required to be fixed and can adaptively vary with changes in startup characteristics under different vehicles, different battery types, and different low-temperature levels.

[0056] When generating the target recharge voltage and its rate of change constraints, S40 uses the recharge boundary conditions as initial recharge constraint inputs. These constraints limit the initial segment of the recharge strategy in terms of amplitude, rate, and current, ensuring that the initial value, rise rate, and allowable recharge intensity of the target recharge voltage match the actual electrical parameters after startup. This way, even if the subsequent recharge voltage adaptively adjusts with temperature characteristics and equivalent internal resistance, the recharge boundary conditions still ensure that the recharge strategy unfolds more smoothly and conservatively within the high-risk range immediately following startup, reducing control repetitions and protection triggers.

[0057] The technical solution implemented in this embodiment can transform the voltage / current response information during the startup phase into initial constraints that can be directly used during the recharge phase, thereby avoiding the problem of "immediately charging after startup" caused by the separation of startup and recharge strategies. By using one or more constraints among recharge initiation voltage limit, recharge initiation current limit, and recharge voltage rise rate limit, the high terminal voltage and recharge oscillation caused by residual polarization after startup at low temperatures can be suppressed, reducing frequent current limiting and protection triggering, making the recharge process smoother and more stable. At the same time, the boundary conditions are updated with startup events, which can improve the adaptability and consistency of the recharge strategy under different low temperature conditions and different battery states, improve low temperature recharge efficiency, and improve the overall vehicle user experience.

[0058] Furthermore, the S40 generates the target recharge voltage and its rate of change constraints, including: The target recharge voltage is updated according to a preset control cycle, and an upper limit is set for the difference between the target recharge voltages of two adjacent control cycles to form a rate of change constraint.

[0059] The initial value of the target recharge voltage is determined by the temperature feature set and the equivalent internal resistance parameter, and is subject to the recharge boundary conditions during the update process.

[0060] In this embodiment, it should be noted that the generation of the target recharge voltage and its rate of change constraint is primarily achieved by transforming the low-temperature recharge process from a "fixed threshold set all at once" to a continuous control method that "updates on a rolling basis according to the control cycle and limits the adjustment speed." Specifically, the system uses a preset control cycle as the update interval. Within each control cycle, the target recharge voltage is calculated or corrected once based on the current temperature feature set, equivalent internal resistance parameters, and recharge boundary conditions. Simultaneously, to avoid control repetitions caused by short-term abnormal voltage spikes due to polarization at low temperatures, or recharge strategy jumps caused by generator-side fluctuations, this embodiment sets an upper limit on the difference between the target recharge voltages of two adjacent control cycles, thus controlling the rate of change of the target recharge voltage and forming a rate of change constraint. This rate of change constraint can be understood as a limitation on "how much can be adjusted at most per control cycle" for the recharge voltage. Its function is to suppress artificially high values, misjudgments, and oscillations caused by rapid surges in the recharge voltage, ensuring a smooth evolution of the recharge voltage over time.

[0061] The initial value of the target recharge voltage does not start from an arbitrary default value, but is jointly determined by a temperature feature set and an equivalent internal resistance parameter. The temperature feature set reflects the low-temperature level and thermal state trend, while the equivalent internal resistance parameter reflects the current charging acceptability and polarization risk. Both are used to select or calculate the initial setting of the recharge voltage, ensuring that recharging starts from a set of initial values ​​that match the current low-temperature state, avoiding instability or frequent protection triggers caused by using room-temperature initial values ​​at low temperatures. Simultaneously, recharge boundary conditions are introduced as constraints during the update process. In the initial stage immediately after startup, the target recharge voltage is limited by constraints such as the recharge initiation voltage, recharge initiation current, or recharge voltage rise rate, thus achieving a smooth transition from startup to recharge. As the battery state gradually recovers and the boundary conditions are met for release or relaxation, the target recharge voltage is gradually released under the rate of change constraint, improving recharge efficiency.

[0062] The technical solution implemented in this embodiment can transform the recharge voltage adjustment process into a controllable continuous transition by updating the target recharge voltage difference between adjacent cycles on a rolling basis. This significantly reduces recharge oscillations and frequent current limiting caused by high terminal voltage, generator fluctuations, or parameter mutations during low-temperature recharge. The target recharge voltage starts from a reasonable initial value determined by temperature characteristics and equivalent internal resistance, and is constrained by recharge boundary conditions during the update process. This avoids voltage surges and misjudgments caused by immediate recharge after startup, making the recharge strategy more aligned with the rechargeable capacity changes of sodium-ion start-stop batteries at low temperatures. This ensures stability while improving low-temperature recharge efficiency and consistency.

[0063] Furthermore, S50 suppresses abnormal changes in terminal voltage during the recharge process by including: When the terminal voltage rises faster than a preset threshold during the recharge process and / or the terminal voltage rises abnormally without an increase in the recharge current, and the temperature feature set indicates a low temperature level, the low temperature polarization criterion is satisfied, thereby reducing the target recharge voltage and / or tightening the rate of change constraint of the target recharge voltage.

[0064] When the low temperature level characterized by the temperature feature set reaches the preset threshold and the equivalent internal resistance parameter is higher than the preset threshold, an intermittent pulse reheat and recharge strategy is adopted to adjust the recharge voltage in a pulse manner to promote temperature rise.

[0065] When the cell temperature rises to a preset threshold and / or the equivalent internal resistance parameter decreases to a preset threshold, the target recharge voltage and its rate of change constraint are relaxed as a release condition, and continuous recharge is resumed.

[0066] In this embodiment, it should be noted that sodium-ion start-stop batteries are more prone to increased polarization and "falsely high terminal voltage" during low-temperature recharging. This means the terminal voltage rises rapidly at the beginning or during recharging, but this rise does not necessarily represent an increase in actual charging capacity. If the recharging voltage is continued to be increased in the conventional way, it can easily trigger frequent current limiting, control oscillations, or misjudgment of full charge. This embodiment introduces logic to suppress abnormal changes in terminal voltage in S50. A low-temperature polarization criterion is established based on the observable relationship between the terminal voltage rise rate and the recharging current change: when the terminal voltage rise rate exceeds a preset threshold, and / or when an abnormal rise in terminal voltage occurs without an increase in the recharging current, and the temperature feature set indicates a low-temperature level, the low-temperature polarization criterion is satisfied. The key design point of this criterion is to use "whether the voltage rise matches the current intensity" as the basis for anomaly identification, thereby distinguishing between voltage rise caused by normal recharging and falsely high voltage caused by polarization.

[0067] Once the low-temperature polarization criterion is met, this embodiment does not directly cut off the recharge process. Instead, it adjusts the process using a "soft suppression" method, that is, reducing the target recharge voltage and / or tightening the rate of change constraint of the target recharge voltage. This makes the recharge voltage rise more gradually and the recharge intensity more conservative, thereby suppressing the continued abnormal rise of the terminal voltage and avoiding repeated control. Since the recharge strategy of this application adopts a combination of target recharge voltage and rate of change constraint control, a rapid response to anomalies can be achieved through two paths: adjusting the target value and tightening the rate of change. This reduces the risk at low temperatures while maintaining the continuity and recoverability of the recharge process.

[0068] When the low-temperature level characterized by the temperature feature set reaches a preset threshold and the equivalent internal resistance parameter is higher than the preset threshold, it indicates that the battery is in a more "cold and high-resistance" constrained operating condition. Simply reducing the target recharge voltage may lead to excessively low recharge efficiency, making it difficult to promote battery warming. This embodiment employs an intermittent pulsed recharge-temperature recovery strategy under these conditions: the recharge voltage is adjusted via pulses to input energy with a small duty cycle, reducing continuous polarization accumulation through intermittent recharge. Simultaneously, under controllable heat input, it promotes a rise in cell temperature and a decrease in equivalent internal resistance. The pulsed recharge phase can still be linked to the target recharge voltage and rate of change constraints, such as limiting the pulse amplitude, pulse rise speed, or pulse duration to ensure a smooth and controllable recharge process.

[0069] The pulsed recharge mechanism is not maintained indefinitely. When the cell temperature rises to a preset threshold and / or the equivalent internal resistance parameter decreases to a preset threshold, the system relaxes the constraints on the target recharge voltage and its rate of change, and resumes continuous recharge, as a release condition. This release mechanism allows the recharge control to automatically "shift from conservative to relaxed" as the battery's thermal state improves, avoiding insufficient recharge due to prolonged excessive current limiting, and also avoiding premature relaxation before the battery has warmed up, which could lead to repolarization anomalies.

[0070] The technical solution implemented in this embodiment can construct an observable polarization criterion by relating the terminal voltage rise rate to the recharge current during low-temperature recharge, promptly identify abnormal trends such as artificially high terminal voltage, and achieve flexible suppression by reducing the target recharge voltage and / or tightening the rate of change constraint, thereby reducing frequent current limiting, misjudgment, and recharge oscillation. In more stringent low-temperature and high-internal-resistance operating conditions, an intermittent pulse temperature recovery and recharge strategy is introduced, which can improve the temperature recovery efficiency while controlling polarization risk. After the cell temperature rises and the internal resistance decreases, the conservative constraint is automatically released and continuous recharge is resumed, thus taking into account low-temperature safety, recharge stability, and recharge efficiency, and improving the overall availability and consistency of sodium-ion start-stop batteries in winter start-stop scenarios.

[0071] This application also provides an adaptive control system for low-temperature start-up and recharge of sodium-ion start-stop battery based on MCU-BMS collaboration, which is applied to the adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop battery based on MCU-BMS collaboration as described above. Further, it includes: sodium-ion start-stop battery body, temperature sensing component, electrical parameter acquisition component, MCU controller, BMS, and recharge adjustment interface.

[0072] The sodium-ion start-stop battery body includes a cell, terminals or a casing. Temperature sensing components are respectively arranged in the cell, terminals or casing and in the environment, and output temperature signals. Electrical parameter acquisition components are electrically connected to the terminals of the sodium-ion start-stop battery body and output terminal voltage and current signals.

[0073] The MCU controller is electrically or communicatively connected to the temperature sensing component and the electrical parameter acquisition component to receive temperature, terminal voltage, and current signals. It also connects to the vehicle's charging side via the recharge adjustment interface to output a recharge voltage setting signal. The MCU controller is also connected to the start-up circuit of the sodium-ion start-stop battery to output a start-up discharge control signal.

[0074] The BMS communicates with the MCU controller. The BMS outputs a battery status feedback signal to the MCU controller, and the MCU controller sends back the electrical parameter characteristic signals of the startup phase and / or the recharge execution result signal to the BMS.

[0075] In this embodiment, it should be noted that the system constructs a collaborative closed loop using a dual-path architecture of "sodium-ion start-stop battery body - acquisition component - MCU controller - recharge adjustment interface - vehicle charging side" and "MCU controller - BMS". The focus is not on simply stacking hardware modules, but on providing a unified data foundation and feasible execution channel for low-temperature start control and low-temperature recharge adaptive control through clearly defined signal sources, destinations, and connections. Specifically, the sodium-ion start-stop battery body includes cells and terminals or a casing, providing electrical connection ports for start-up power supply and recharge power reception, as well as a clearly defined measured object for temperature sampling. Temperature sensing components are respectively arranged in the cells, terminals or casing, and environmental locations, forming multi-point sensing of the battery's thermal state and external cooling conditions, and outputting temperature signals to the control link. The electrical parameter acquisition component is electrically connected to the battery terminals, forming acquisition channels for terminal voltage and current signals, thereby ensuring that the electrical parameter inputs relied upon by the control strategy come from the actual port state of the battery rather than indirect estimation.

[0076] The MCU controller is centrally located for execution and coordination. On one hand, it receives temperature, terminal voltage, and current signals through electrical or communication connections with temperature sensing components and electrical parameter acquisition components, providing input for low-temperature state identification, equivalent internal resistance estimation, start-up capability assessment, and recharge parameter generation. On the other hand, it establishes an execution link with the vehicle's charging side through the recharge adjustment interface to output a recharge voltage setting signal, enabling the vehicle-side generator or power regulation unit to adjust the recharge voltage according to control requirements. Simultaneously, the MCU controller connects to the start-up circuit of the sodium-ion start-stop battery to output a start-up discharge control signal during the start-up phase, thereby achieving controllable constraints on the start-up discharge process. By incorporating the start-up circuit and the recharge adjustment interface into the MCU controller's connection system, "start-up control" and "recharge control" can form a continuous strategy execution path under the same control entity, avoiding the separation of the two-stage control.

[0077] The communication connection between the BMS and the MCU controller is used to construct a "policy-state" closed loop: the BMS outputs battery state feedback signals to the MCU controller, enabling the MCU's control parameters to be adjusted in response to changes in battery state; simultaneously, the MCU controller sends back characteristic signals of electrical parameters during the startup phase and / or recharge execution results signals to the BMS, allowing the BMS to obtain external execution information about startup events and the recharge process for subsequent state diagnosis, recording, and coordinated control. This bidirectional information path ensures that the state management at the battery end and the execution adjustment at the vehicle end are aligned, especially in low-temperature environments, avoiding misjudgments and repeated adjustments caused by relying solely on information from one side.

[0078] The technical solution implemented in this embodiment can establish a unified data entry point required for low-temperature control through multi-point temperature sampling and terminal voltage / current sampling, providing a stable and traceable input foundation for low-temperature start-up and low-temperature recharge adaptive control. By connecting the start-up circuit and the recharge adjustment interface simultaneously through the MCU controller, a continuous execution link is formed from start-up discharge constraints to recharge voltage setting, improving the controllability of the low-temperature start-up phase and the feasibility of the recharge phase. Furthermore, the closed-loop interaction between battery status and execution results is achieved through bidirectional communication between the MCU and the BMS, enabling control parameters to be dynamically adjusted according to changes in low-temperature operating conditions and battery status. This reduces terminal voltage spikes, frequent current limiting, and control oscillations during low-temperature recharge, improving vehicle availability, recharge stability, and system safety in winter start-stop scenarios.

[0079] Furthermore, a bidirectional communication interface is provided between the MCU controller and the BMS. The bidirectional communication interface includes: a first bus interface circuit electrically connected to the communication port of the MCU controller, a second bus interface circuit electrically connected to the communication port of the BMS, and a bus connection line connecting the first bus interface circuit and the second bus interface circuit.

[0080] The first bus interface circuit and / or the second bus interface circuit include at least a bus transceiver, a terminal matching unit, and a connector unit. The terminal matching unit is electrically connected to the bus connection line, and the connector unit is used to detachably connect the bus connection line to the MCU controller and the BMS.

[0081] In this embodiment, it should be noted that, to achieve stable coordination between the MCU controller and BMS during low-temperature start-up and recharge control, a bidirectional communication interface is provided between them, and a reliable vehicle communication link is achieved using a structured approach of "interface circuit—connection line—detachable connection". The bidirectional communication interface includes a first bus interface circuit, a second bus interface circuit, and a bus connection line: the first bus interface circuit is electrically connected to the communication port of the MCU controller, used to convert the communication signals from the MCU controller side into levels and driving capabilities suitable for bus transmission; the second bus interface circuit is electrically connected to the communication port of the BMS, used to complete signal conversion between the BMS side and the bus side; the bus connection line connects the first bus interface circuit and the second bus interface circuit, forming a bidirectional information transmission channel between the MCU and the BMS. By placing the bus interface circuits near the controllers at both ends, the signal integrity issues caused by the controller ports directly driving long wiring harnesses can be reduced, making the communication link more adaptable to the vehicle wiring environment.

[0082] The first bus interface circuit and / or the second bus interface circuit include at least a bus transceiver, a termination matching unit, and a connector unit. The bus transceiver is used to convert between controller port signals and bus signals. The termination matching unit is electrically connected to the bus connection lines and is used for impedance matching and reflection suppression of the bus lines to reduce the risk of communication errors caused by long wiring harnesses, branch lines, or electromagnetic interference. The connector unit is used to provide a detachable electrical connection between the bus connection lines and the MCU controller and BMS, making the communication interface easy to assemble and maintain. The introduction of detachable connections also facilitates the rapid replacement of wiring harnesses, controllers, or BMS during vehicle production or after-sales maintenance, while reducing the impact of poor connector contact caused by long-term vibration and temperature cycling on communication stability.

[0083] The technical solution implemented in this embodiment can improve the stability and anti-interference capability of bidirectional communication between the MCU controller and BMS under the conditions of low temperature and electromagnetic interference in the vehicle environment through a dual-ended bus interface structure of "transceiver + terminal matching + detachable connection". This reduces the risk of collaborative control failure caused by bus reflection and bit errors. At the same time, the detachable connection improves the convenience of system assembly and maintenance, reduces the interruption of status feedback or failure of execution information return caused by connection failure, thereby providing a reliable communication foundation for the closed-loop coordination of low temperature start-up and recharge adaptive control.

[0084] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. An adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration, characterized in that, include: S10. Collect the cell temperature, terminal or casing temperature and ambient temperature of the sodium-ion start-stop battery to generate a temperature feature set for low-temperature control. S20. Collect the terminal voltage and current information of the sodium-ion start-stop battery, and calculate the equivalent internal resistance parameter in combination with the temperature feature set; S30. Determine the start-up capability window based on the temperature feature set and the equivalent internal resistance parameter, and control the start-up discharge of the sodium-ion start-stop battery within the start-up capability window. Record the voltage response and current characteristics during the startup phase to generate recharge boundary conditions; S40. Based on the temperature feature set, the equivalent internal resistance parameter, and the recharge boundary condition, generate a target recharge voltage and its rate of change constraint, so that the target recharge voltage is adaptively adjusted as the equivalent internal resistance parameter changes. S50. The sodium-ion start-stop battery is recharged according to the target recharge voltage and its rate of change constraint, and the abnormal changes in terminal voltage during the recharge process are suppressed by adjusting the target recharge voltage and / or tightening the rate of change constraint. S60. Receive the recharge execution result and battery status feedback, and update the temperature feature set, the equivalent internal resistance parameter, and / or the target recharge voltage and its rate of change constraint accordingly.

2. The adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration according to claim 1, characterized in that, The temperature feature set generated by S10 includes: The cell temperature and the terminal or casing temperature are sampled at least twice redundantly and a consistency check is performed. The consistency check includes at least drift judgment, jump judgment or out-of-bounds judgment. When redundancy inconsistency is determined, the alternative temperature value after consistency verification is used to participate in the generation of temperature feature set, and the corresponding derating or protection flag is output.

3. The adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration according to claim 1, characterized in that, The temperature feature set includes: Low temperature rating and temperature difference characterization, wherein the low temperature rating is obtained by mapping the cell temperature to the ambient temperature, and the temperature difference characterization is calculated by the difference between the cell temperature and the terminal or casing temperature and / or the difference between the cell temperature and the ambient temperature; The low temperature level is used in S30 to select the start-up capability window parameter set corresponding to the low temperature level, and in S40 to select the initial recharge voltage parameter set corresponding to the low temperature level.

4. The adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration according to claim 1, characterized in that, The S20 calculation of the equivalent internal resistance parameters includes: A short-time current disturbance is applied to a sodium-ion start-stop battery and the terminal voltage response is collected. The equivalent internal resistance parameter is calculated based on the short-time current disturbance and the terminal voltage response. The validity of the equivalent internal resistance parameters is determined based on the consistency of the equivalent internal resistance parameters obtained from at least two short-time current disturbances and / or the fitting residual of the terminal voltage response. When the equivalent internal resistance parameter is determined to be invalid, a short-time current disturbance is reapplied and recalculated, or the equivalent internal resistance parameter of the previous control cycle is used in subsequent S30 and S40.

5. The adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration according to claim 1, characterized in that, The S30 determination of the startup capability window includes: The upper limit of the allowable start-up discharge current and / or the lower limit of the allowable start-up terminal voltage are determined based on the temperature feature set and the equivalent internal resistance parameter, and the start-up capability window is formed by the upper limit of the start-up discharge current and / or the lower limit of the start-up terminal voltage. During the startup control process, when the startup terminal voltage is detected to be lower than the startup terminal voltage lower limit and / or the startup discharge current reaches the startup discharge current upper limit, the startup discharge control quantity is adjusted to make the startup process meet the startup capability window constraint.

6. The adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration according to claim 1, characterized in that, The S30 generation of recharge boundary conditions includes: The voltage response characteristics and current characteristics during the startup phase are statistically analyzed or extracted to obtain one or more of the following: recharge initiation voltage limit, recharge initiation current limit, and recharge voltage rise rate limit, which constitute the recharge boundary conditions. When generating the target recharge voltage and its rate of change constraint, S40 uses the recharge boundary condition as the initial recharge constraint input.

7. The adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration according to claim 1, characterized in that, The S40 generates the target recharge voltage and its rate of change constraint, including: The target recharge voltage is updated according to a preset control cycle, and an upper limit is set for the difference between the target recharge voltages of two adjacent control cycles to form the rate of change constraint. The initial value of the target recharge voltage is determined by the temperature feature set and the equivalent internal resistance parameter, and is subject to the recharge boundary conditions during the update process.

8. The adaptive control method for low-temperature start-up and recharge of sodium-ion start-stop batteries based on MCU-BMS collaboration according to claim 1, characterized in that, The S50 method for suppressing abnormal changes in terminal voltage during the recharge process includes: When the terminal voltage rise rate exceeds the preset threshold during the recharge process and / or the terminal voltage rises abnormally without an increase in the recharge current, and the temperature feature set is characterized as a low temperature level, the low temperature polarization criterion is determined to be met, thereby reducing the target recharge voltage and / or tightening the rate of change constraint of the target recharge voltage. When the low temperature level characterized by the temperature feature set reaches the preset threshold and the equivalent internal resistance parameter is higher than the preset threshold, an intermittent pulse reheating and recharging strategy is adopted to adjust the recharge voltage in a pulse manner to promote temperature rise. When the cell temperature rises to a preset threshold and / or the equivalent internal resistance parameter decreases to a preset threshold, the target recharge voltage and its rate of change constraint are relaxed as a release condition, and continuous recharge is resumed.

9. A sodium-ion start-stop battery low-temperature start-up and recharge adaptive control system based on MCU-BMS collaboration, applied to the sodium-ion start-stop battery low-temperature start-up and recharge adaptive control method based on MCU-BMS collaboration as described in any one of claims 1-8, characterized in that, include: Sodium-ion start-stop battery body, temperature sensing component, electrical parameter acquisition component, MCU controller, BMS and recharge regulation interface; The sodium-ion start-stop battery body includes a cell, terminals or a casing; the temperature sensing component is respectively arranged in the cell, terminals or casing and the environment and outputs a temperature signal; the electrical parameter acquisition component is electrically connected to the terminals of the sodium-ion start-stop battery body and outputs terminal voltage signal and current signal. The MCU controller is electrically or communicatively connected to the temperature sensing component and the electrical parameter acquisition component to receive the temperature signal, terminal voltage signal and current signal, and is connected to the vehicle charging side through the recharge adjustment interface to output the recharge voltage setting signal; the MCU controller is also connected to the start-up circuit of the sodium-ion start-stop battery body to output the start-up discharge control signal. The BMS is communicatively connected to the MCU controller. The BMS outputs a battery status feedback signal to the MCU controller, and the MCU controller sends back the start-up phase electrical parameter characteristic signal and / or recharge execution result signal to the BMS.

10. The adaptive control system for low-temperature start-up and recharge of sodium-ion start-stop battery based on MCU-BMS collaboration according to claim 9, characterized in that, The MCU controller and the BMS are provided with a bidirectional communication interface. The bidirectional communication interface includes: a first bus interface circuit electrically connected to the communication port of the MCU controller, a second bus interface circuit electrically connected to the communication port of the BMS, and a bus connection line connecting the first bus interface circuit and the second bus interface circuit. The first bus interface circuit and / or the second bus interface circuit include at least a bus transceiver, a terminal matching unit, and a connector unit. The terminal matching unit is electrically connected to the bus connection line, and the connector unit is used to detachably connect the bus connection line to the MCU controller and the BMS.

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