A method and device for under-voltage protection of a battery pack in park mode

Abstract

The application discloses a kind of battery pack under parking mode under-voltage protection method and device, it is related to the field of automobile electronics, the method comprises: obtaining the system power consumption after being set vehicle main circuit breaker is disconnected, and according to the system maintenance time and system power consumption that user pre-set, determine the battery capacity threshold that being set vehicle needs to reserve;According to the cell voltage-capacity curve that is built, battery capacity threshold is converted into cell voltage threshold;Cell voltage-capacity curve is used to characterize the mapping relationship between battery voltage and battery capacity in the process of battery discharge;Determine the real-time cell minimum voltage of battery pack, under the condition that real-time cell minimum voltage is less than cell voltage threshold, trigger parking mode under-voltage protection and disconnect main circuit breaker.The application can return to PM UVP demand itself, ensure that low-voltage battery pack can maintain a period of power supply demand after CB is disconnected, avoid over-discharge of low-voltage battery pack.

Description

Technical Field

[0001] This invention relates to the field of automotive electronics, and more specifically to a method and apparatus for undervoltage protection of a battery pack in parking mode. Background Technology

[0002] With the popularization of new energy vehicles, the level of vehicle intelligence is constantly improving. When the vehicle is in Park Mode (PM) and not in motion, the high voltage (HV) system is usually disconnected to save energy and ensure vehicle safety. However, some critical vehicle systems, such as the Battery Management System (BMS), telematics unit, anti-theft system, and keyless entry, still require continuous power to maintain basic monitoring, communication, and security functions. These functions are usually powered by low-voltage battery packs, such as 12V or 24V battery packs, which serve as the vehicle's starting power and backup power during operation.

[0003] To ensure the vehicle can still start normally after prolonged periods of inactivity and to prevent damage to the low-voltage battery pack from over-discharge due to continuous low-current discharge, a reasonable Park Mode Undervoltage Protection (PMUVP) strategy must be designed in the BMS. The core objective of this strategy is to proactively disconnect the low-voltage battery pack's circuit breaker (CB) when it is determined that the battery charge is insufficient to support critical systems until the next predetermined maintenance cycle, such as ensuring the vehicle can still start after being inactive for 6 months. This protects the battery from over-discharge, ensuring the low-voltage battery pack retains sufficient residual state of charge (SOC), while avoiding premature CB disconnection that could lead to vehicle malfunction.

[0004] In existing technologies, mainstream PM UVP strategies typically rely on the battery pack's State of Charge (SOC) for judgment. By estimating the real-time SOC, PM UVP is initiated and the battery bank (CB) is disconnected when the real-time SOC does not exceed a preset trigger threshold. However, issues with both the accuracy of SOC estimation and the setting of the trigger threshold can lead to premature or delayed PM UVP triggering. Premature PM UVP triggering will prematurely disconnect the CB, causing immediate failure of vehicle remote control, status monitoring, and other functions. It may even prevent the vehicle from being woken up due to a BMS power failure, resulting in a false sense of vehicle depletion, a poor user experience, and potentially requiring unnecessary roadside assistance. Conversely, delayed PM UVP triggering will disconnect the CB too late, with the CB only acting when the battery is almost depleted, i.e., the true SOC value is close to 0%. This can lead to deep over-discharge of the battery, causing irreversible chemical damage, significantly shortening battery life, and even posing safety hazards.

[0005] Therefore, how to provide a method to trigger PM UVP at a more accurate and appropriate time, so as to avoid triggering PM UVP prematurely or delayedly, is an important issue that the industry urgently needs to address. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a method and apparatus for undervoltage protection of a battery pack in parking mode, thereby solving the problem that existing PM UVP triggering strategies are prone to premature or delayed triggering.

[0007] According to a first aspect, embodiments of the present invention provide an undervoltage protection method for a battery pack in parking mode, the method comprising: The system power consumption after the main circuit breaker of the vehicle to be configured is disconnected is obtained, and the battery capacity threshold that the vehicle to be configured needs to reserve is determined based on the system maintenance time and system power consumption preset by the user. Based on the constructed cell voltage-capacity curve, the battery capacity threshold is converted into the cell voltage threshold. The cell voltage-capacity curve is used to characterize the mapping relationship between battery voltage and battery capacity during the battery pack discharge process. The cell voltage-capacity curve is constructed based on the battery pack model information, ambient temperature, health status, and discharge rate. Determine the real-time minimum cell voltage of the battery pack. If the real-time minimum cell voltage is less than the cell voltage threshold, trigger the parking mode undervoltage protection and disconnect the main circuit breaker.

[0008] In conjunction with the first aspect, in the first embodiment of the first aspect, the step of converting the battery capacity threshold into a cell voltage threshold based on the constructed cell voltage-capacity curve specifically includes: Determine the battery pack model information and use it as the first index information; Based on the first index information, match the cell voltage-capacity curve of the same model sample battery to the vehicle to be set; Determine the operating data and use the model information as the second index information; the operating data includes health status, ambient temperature, and discharge rate. Based on the second index information, match the cell voltage-capacity curve with the same operating data for the vehicle to be configured; Using the battery capacity threshold as the third index information, the battery capacity threshold is converted into the cell voltage threshold based on the cell voltage-capacity curve under the same operating data.

[0009] In conjunction with the first aspect, in the second embodiment of the first aspect, determining the real-time minimum cell voltage of the battery pack, and triggering the parking mode undervoltage protection and disconnecting the main circuit breaker when the real-time minimum cell voltage is determined to be less than the cell voltage threshold, specifically includes: Determine the real-time cell voltage of each cell in the series-connected battery pack at each moment; The minimum value among all real-time cell voltages at each moment is taken as the real-time minimum cell voltage at the corresponding moment. If the real-time minimum cell voltage is determined to be less than the cell voltage threshold, the parking mode undervoltage protection is triggered and the main circuit breaker is disconnected.

[0010] In conjunction with the first aspect, in the third embodiment of the first aspect, the cell voltage-capacity curve is constructed in the following manner: Each sample battery with different model information and different health status was placed under various ambient temperatures and constant current discharge was performed on each sample battery with an initial state of charge of 100% at different discharge rates. The battery voltage and battery capacity of each sample battery during the discharge process were determined. Based on the battery voltage and battery capacity of the sample batteries, a mapping relationship between battery voltage and battery capacity is established to obtain the cell voltage-capacity curve of each sample battery during the discharge process. Establish cell voltage-capacity curves and establish the mapping relationship between cell voltage-capacity curves and model information, health status, and discharge rate.

[0011] In conjunction with the first aspect, in the fourth embodiment of the first aspect, the establishment of the cell voltage-capacity curve and the establishment of the mapping relationship between the cell voltage-capacity curve and model information, health status, and discharge rate specifically includes: Based on the battery voltage and battery capacity during the discharge process of the sample batteries under different health conditions, ambient temperatures, and discharge rates, cell voltage-capacity curves of the sample batteries were established to obtain cell voltage-capacity curves of the same model of sample batteries under different conditions. Establish the mapping relationship between cell voltage-capacity curves and health status, ambient temperature, and discharge rate to obtain several offline tables for sample batteries of the same model; An offline table compiles sample battery information for all models, and a mapping relationship is established between the offline table and the model information.

[0012] In conjunction with the first aspect, in the fifth embodiment of the first aspect, the cell voltage-capacity curve is constructed in the following manner: Each sample battery with different model information and different health status was placed under various ambient temperatures to determine the initial state of charge of the sample batteries. Each sample battery was subjected to constant current discharge at different discharge rates, and the battery voltage and battery capacity of each sample battery during the discharge process were determined. Based on the battery voltage and battery capacity of the sample batteries, a mapping relationship between battery voltage and battery capacity is established to obtain the cell voltage-capacity curve of each sample battery during the discharge process. Establish cell voltage-capacity curves and establish the mapping relationship between cell voltage-capacity curves and initial state of charge, model information, health status, and discharge rate.

[0013] In conjunction with the first aspect, in the sixth embodiment of the first aspect, the method further includes the following steps: The system power consumption after the main circuit breaker of the vehicle to be configured is disconnected is obtained. Based on the system maintenance time and system power consumption preset by the user, the battery reference threshold that the vehicle to be configured needs to reserve is determined. Based on the battery reference threshold and the preset gain coefficient, the battery capacity threshold is determined.

[0014] According to a second aspect, embodiments of the present invention also provide an undervoltage protection device for a battery pack in parking mode, the device comprising: The capacity calculation module is used to obtain the system power consumption after the main circuit breaker of the vehicle to be set is disconnected, and to determine the battery capacity threshold that the vehicle to be set needs to reserve based on the system maintenance time and system power consumption preset by the user. The capacity mapping module is used to convert the battery capacity threshold into the cell voltage threshold based on the constructed cell voltage-capacity curve. The cell voltage-capacity curve is used to characterize the mapping relationship between battery voltage and battery capacity during the battery pack discharge process. The cell voltage-capacity curve is constructed based on the battery pack model information, ambient temperature, health status and discharge rate. The undervoltage protection module is used to determine the real-time minimum cell voltage of the battery pack. If the real-time minimum cell voltage is determined to be less than the cell voltage threshold, the parking mode undervoltage protection is triggered and the main circuit circuit breaker is disconnected.

[0015] According to a third aspect, embodiments of the present invention also provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the undervoltage protection method for a battery pack in parking mode as described above.

[0016] According to a fourth aspect, embodiments of the present invention also provide a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the undervoltage protection method for a battery pack in parking mode as described above.

[0017] The undervoltage protection method and apparatus for a battery pack in parking mode of the present invention obtains the system power consumption after the main circuit breaker of the vehicle to be set is disconnected, and determines the battery capacity threshold that the vehicle to be set needs to reserve based on the user-preset system maintenance time and system power consumption. Then, according to the constructed cell voltage-capacity curve, the battery capacity threshold is converted into a cell voltage threshold, so that PM UVP triggering is linked to the actual remaining usable capacity of the battery pack, and does not rely on the state of charge as PM, which is calculated in real time and has accumulated errors. The direct basis of UVP ensures that, under any battery aging level, temperature, or load conditions, the battery charge remaining in the battery pack before the main circuit breaker disconnects can maintain the vehicle system for the preset system maintenance time. This completely avoids premature or late triggering due to inaccurate SOC estimation or unreasonable fixed thresholds. Furthermore, since the cell voltage threshold parameter has a corresponding mapping relationship with the battery capacity threshold, health status, ambient temperature, and discharge rate, the specific value of the cell voltage threshold will be dynamically adjusted adaptively according to the battery capacity threshold, health status, ambient temperature, and discharge rate. This allows the cell voltage threshold to automatically and continuously adapt to the performance degradation throughout the battery's entire life cycle and respond to real-time changes in ambient temperature and load current. This adaptive capability ensures that the protection strategy maintains consistent performance throughout the vehicle's entire lifespan and under various geographical and climatic conditions. This setting returns to the PM UVP requirement itself, ensuring that the low-voltage battery pack can maintain power supply for a period of time after the CB disconnects, preventing over-discharge of the low-voltage battery pack. Attached Figure Description

[0018] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings: Figure 1 A flowchart illustrating the undervoltage protection method for a battery pack in parking mode provided by the present invention is shown. Figure 2 The invention illustrates an offline table for 100% of the low-voltage battery pack in the undervoltage protection method for the battery pack in parking mode, constructed based on cell voltage-capacity. Figure 3 The following is an offline table showing the low-voltage battery pack of xx1% in the parking mode undervoltage protection method provided by the present invention, which is constructed based on cell voltage-capacity. Figure 4 The following is an offline table showing the xx2% low-voltage battery pack in the undervoltage protection method for the battery pack in parking mode provided by the present invention, which is constructed based on the cell voltage-capacity. Figure 5 The following is an offline table showing the xx3% low-voltage battery pack in the undervoltage protection method for the battery pack in parking mode provided by the present invention, which is constructed based on the cell voltage-capacity. Figure 6 A schematic diagram of the undervoltage protection device for the battery pack in parking mode provided by the present invention is shown. Figure 7 A schematic diagram of the hardware structure of the electronic device provided in an embodiment of this application is shown. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] With the popularization of new energy vehicles, the level of vehicle intelligence is constantly improving. When the vehicle is not in motion (PM), the vehicle's power supply (HV) is usually disconnected to save energy and ensure vehicle safety. However, some critical vehicle systems, such as the BMS itself, telematics unit, anti-theft system, and keyless entry, still require continuous power to maintain basic monitoring, communication, and security functions. These functions are usually powered by low-voltage battery packs, such as 12V or 24V battery packs, which serve as the vehicle's starting power and backup power during operation.

[0021] To ensure the vehicle can still start normally after prolonged periods of inactivity and to prevent over-discharge damage to the low-voltage battery pack due to continuous low-current discharge, a reasonable PMUVP strategy must be designed in the BMS. The core objective of this strategy is to proactively disconnect the CB (Continuous Circuit Breaker) of the low-voltage battery pack when it is determined that the battery charge is insufficient to support the operation of critical systems until the next predetermined maintenance cycle, such as ensuring the vehicle can still start after 6 months of inactivity. This protects the battery from over-discharge, ensuring the low-voltage battery pack retains sufficient remaining SOC (State of Charge), while avoiding premature disconnection of the CB that could lead to vehicle malfunction.

[0022] In existing technologies, mainstream PM UVP strategies typically determine the battery pack's state of charge (SOC) based on the battery pack's SOC. The specific control logic is as follows: First, the state of charge (SOC) of the battery pack is estimated in real time using the ampere-hour integration method, open-circuit voltage method, or a data-driven model. When the real-time SOC does not exceed a preset trigger threshold, PM UVP is performed, and the battery bank (CB) is disconnected. In particular, some PM UVP strategies also introduce a temperature compensation mechanism, which is used to slightly increase the trigger threshold at low temperatures to compensate for the reduction in usable battery capacity at low temperatures.

[0023] However, current SOC estimation processes are affected by various factors, including current measurement accuracy, temperature, battery aging, self-discharge, and resting time. Especially in parking mode, the current is extremely low, and the noise component in the measurement process is significant, leading to the accumulation of ampere-hour integration errors. Prolonged resting also causes voltage-based SOC estimations to be affected by hysteresis. These errors can cause the estimated real-time SOC to deviate significantly from the battery's true remaining capacity. Batteries exhibit significant differences in discharge curves under different health conditions, discharge rates (and temperatures), and the actual remaining ampere-hour capacity corresponding to a statically fixed trigger threshold may differ by several times under these different operating conditions. For example, the actual usable capacity corresponding to 10% SOC of an aged battery at low temperatures may be far lower than that of a new battery at room temperature. Current temperature compensation mechanisms are too simplistic and lack adaptability. Under extreme low-temperature conditions, some battery capacity is frozen, resulting in an actual usable capacity far lower than the estimated value. However, this capacity may slowly release over time, and simple temperature compensation mechanisms cannot accurately assess this complex effect.

[0024] Either of the above issues can cause PM UVP to trigger prematurely or delayed. When PM UVP triggers prematurely, the CB will be disconnected prematurely, causing functions such as vehicle remote control and status monitoring to immediately fail. It may even fail to wake up due to BMS power failure, resulting in a false sense of vehicle depletion, a poor user experience, and potentially requiring unnecessary roadside assistance. When PM UVP triggers delayedly, the CB will be disconnected too late, with the CB only activating when the battery is almost depleted, i.e., the true SOC value is close to 0%. This can lead to deep over-discharge of the battery, causing irreversible chemical damage, significantly shortening battery life, and even posing safety hazards.

[0025] Specifically, due to an underestimation of SOC and an overly conservative trigger threshold setting, PM UVP may be triggered prematurely when the low-voltage battery pack still has sufficient charge. Conversely, due to an overestimation of SOC and a trigger threshold that fails to adequately reflect capacity degradation under harsh operating conditions, PM UVP may be delayed until the low-voltage battery pack is almost completely depleted.

[0026] In conclusion, how to provide a method to trigger PM UVP at a more accurate and appropriate time, thereby avoiding premature or delayed triggering of PM UVP, is an important issue that the industry urgently needs to address.

[0027] To address the aforementioned issues, this specification provides an undervoltage protection method for the battery pack in parking mode. This method aims to ensure that the low-voltage battery pack maintains its power supply for a period of time after the CB (Power Supply Control) is disconnected, based on the PM (Power, Voltage, and Power) requirements themselves, thus preventing over-discharge of the low-voltage battery pack. The undervoltage protection method for the battery pack in parking mode provided in this specification can be applied to electronic devices, including laptops, desktop computers, smartphones, smart wearable devices, and tablets. Furthermore, the undervoltage protection method for the battery pack in parking mode provided in this specification can also be applied to applications running on the aforementioned electronic devices. Figure 1 This is a flowchart illustrating the undervoltage protection method for a battery pack in parking mode according to an embodiment of the present invention. Figure 1 As shown, the method may include the following steps: S101. Obtain the system power consumption after the main circuit breaker of the vehicle to be configured is disconnected, and determine the battery capacity threshold that the vehicle to be configured needs to reserve based on the user-preset system maintenance time and system power consumption. .

[0028] Based on the original PM UVP requirements, after the circuit breaker CB is disconnected, the remaining power of the vehicle's low-voltage battery pack should be sufficient to sustain the vehicle system for a certain period of time, for example, enough to sustain the vehicle system for 6 months. In this embodiment of the invention, the system power consumption after the main circuit breaker controlling the power supply to the low-voltage battery pack is disconnected is multiplied by the system sustainment time to determine the battery capacity threshold that the battery pack should reserve under normal temperature conditions when the main circuit breaker is disconnected. Specifically:

[0029] in, This indicates the battery capacity threshold, in Ah. This indicates system power consumption, measured in mA / h. This indicates the system uptime, expressed in hours (h).

[0030] For example, for a certain vehicle, after the main circuit breaker is disconnected, the system power consumption, including the BMS and low-voltage battery pack self-discharge, is 0.7 mA / h. Assuming the user requires that the remaining charge of the low-voltage battery pack after PM UVP triggering can still sustain the vehicle system operation for 6 months, and the user-preset system maintenance time is 6 months, the battery capacity threshold... The value is: 0.7 6 30 24 / 1000 = 3.024Ah.

[0031] In this embodiment of the invention, the user can set the specific duration of the system maintenance time according to actual usage needs, and can pre-set several baseline maintenance times for user reference. To prevent the system maintenance time set by the user from deviating from actual needs, minimum and maximum maintenance times can also be pre-set, and the system maintenance time set by the user must not exceed the time range constrained by the minimum and maximum maintenance times.

[0032] The system power consumption is obtained by acquiring the power consumption of the BMS and the self-discharge of the low-voltage battery pack within a preset time period, and dividing the power consumption by the duration represented by the preset time period. The system power consumption can be the average power consumption over a period of time.

[0033] S102. Based on the constructed cell voltage-capacity curve, set the battery capacity threshold. Converted to cell voltage threshold The unit is V.

[0034] In this embodiment of the invention, the cell voltage-capacity curve is used to characterize the mapping relationship between battery voltage and battery capacity during the battery pack discharge process. The cell voltage-capacity curve is constructed based on parameters affecting the battery pack discharge performance, such as battery pack model information, ambient temperature, State of Health (SOH), and discharge rate. The cell voltage-capacity curve can be obtained by conducting experiments on sample batteries of the same model as the low-voltage battery pack of the vehicle to be tested, collecting relevant SOH, ambient temperature, battery voltage, and other information, and then establishing the curve based on this information.

[0035] Because the low-voltage battery packs installed on different vehicles have individual differences, in order to meet the PMUVP triggering requirements of different vehicle models, in this embodiment of the invention, the experimental process will select sample battery packs of multiple models, and the cell voltage-capacity curve will include the battery pack model information as a parameter.

[0036] Based on the cell voltage-capacity curve, the mapping relationship between battery voltage and battery capacity can be determined when a sample battery of the same model as the low-voltage battery pack of the vehicle to be tested is discharged under the same SOH, ambient temperature, and discharge rate conditions. Then, based on the mapping relationship between battery voltage and battery capacity, the result can be obtained when the sample battery discharges to the battery capacity threshold under the same SOH, ambient temperature, and conditions. The corresponding battery voltage at that time is the battery capacity of the low-voltage battery pack when discharged to the battery capacity threshold. The corresponding battery voltage at that time is the aforementioned cell voltage threshold. Then, based on the cell voltage-capacity curve, the calculated battery capacity threshold is... Cell voltage threshold converted to low-voltage battery pack .

[0037] Since ambient temperature and State of Harshness (SOH), which characterizes battery aging, both affect the charge and discharge performance of the low-voltage battery pack, and different discharge rates also affect the rate of energy consumption of the low-voltage battery pack, in this embodiment of the invention, the cell voltage-capacity curve is constructed based on the aforementioned parameters affecting the discharge performance of the low-voltage battery pack. By considering the influence of different ambient temperatures, SOH, and discharge rates on the discharge characteristics of the battery pack of the vehicle to be tested, the battery capacity threshold is then determined. Converted to cell voltage threshold Cell voltage threshold Discharge the low-voltage battery pack of the vehicle to be configured to the battery capacity threshold. The corresponding battery voltage at that time. Due to the cell voltage threshold... This parameter is related to the battery capacity threshold. There is a corresponding mapping relationship between SOH, ambient temperature, and discharge rate, therefore the cell voltage threshold... The specific value will depend on the battery capacity threshold. The system adaptively and dynamically adjusts the SOH, ambient temperature, and discharge rate to optimize the cell voltage threshold. It can automatically and continuously adapt to the performance degradation throughout the entire battery life cycle and respond to real-time changes in ambient temperature and load current. This adaptive capability enables the protection strategy to maintain consistent performance throughout the vehicle's entire lifespan and under various geographical and climatic conditions.

[0038] S103. Determine the real-time minimum cell voltage of the battery pack. In determining the real-time minimum cell voltage Less than the cell voltage threshold In the event of this, the PM UVP is triggered and the main circuit breaker is disconnected.

[0039] In this embodiment of the invention, the minimum real-time battery cell voltage of the vehicle to be configured is obtained at each moment. The obtained real-time minimum cell voltage The cell voltage threshold obtained by conversion The comparison will be performed, and the minimum real-time cell voltage will be determined at a certain moment. Less than the cell voltage threshold In this case, a PM UVP trigger signal is generated and sent via the Controller Area Network (CAN) bus to notify other controllers in the vehicle, thereby driving the hardware circuit of the vehicle to be configured to disconnect the main circuit breaker of the low-voltage battery pack.

[0040] At the minimum voltage of the battery cell Less than the cell voltage threshold In the event of this, the PM UVP is triggered and the main circuit breaker is disconnected, using the reserved cell voltage threshold. This ensures that the low-voltage battery pack can maintain the vehicle system's preset operating time even after the main circuit breaker is disconnected, preventing certain systems in the vehicle from lacking power and failing to operate normally after the main circuit breaker is disconnected, and also preventing the low-voltage battery pack from being over-discharged.

[0041] Specifically, it can save key data each time a PM UVP trigger signal is generated, such as timestamps and real-time minimum cell voltage. Cell voltage threshold Parameters such as SOH and ambient temperature are used for subsequent analysis and optimization of cell voltage-capacity curves.

[0042] The undervoltage protection method for the battery pack in parking mode of the present invention obtains the system power consumption after the main circuit breaker of the vehicle to be set is disconnected, and determines the battery capacity threshold that the vehicle to be set needs to reserve based on the user-preset system maintenance time and system power consumption. Then, according to the constructed cell voltage-capacity curve, the battery capacity threshold is converted into a cell voltage threshold, so that PM UVP triggering is linked to the actual remaining usable capacity of the battery pack, and does not rely on the state of charge as PM calculated in real time and subject to cumulative error. The direct basis of UVP ensures that, under any battery aging level, temperature, or load conditions, the battery charge remaining in the battery pack before the main circuit breaker disconnects can maintain the vehicle system for the preset system maintenance time. This completely avoids premature or late triggering due to inaccurate SOC estimation or unreasonable fixed thresholds. Furthermore, since the cell voltage threshold parameter has a corresponding mapping relationship with the battery capacity threshold, health status, ambient temperature, and discharge rate, the specific value of the cell voltage threshold will be dynamically adjusted adaptively according to the battery capacity threshold, health status, ambient temperature, and discharge rate. This allows the cell voltage threshold to automatically and continuously adapt to the performance degradation throughout the battery's entire life cycle and respond to real-time changes in ambient temperature and load current. This adaptive capability ensures that the protection strategy maintains consistent performance throughout the vehicle's entire lifespan and under various geographical and climatic conditions. This setting returns to the PM UVP requirement itself, ensuring that the low-voltage battery pack can maintain power supply for a period of time after the CB disconnects, preventing over-discharge of the low-voltage battery pack.

[0043] In this embodiment of the invention, step S102 specifically includes: S1021. Determine the battery pack model information and use it as the primary index information. The model information is obtained from vehicle information, battery nameplate, product specifications, or official parameters.

[0044] S1022. Based on the first index information, match the cell voltage-capacity curve of the same model sample battery to the vehicle to be set.

[0045] Based on the first index information, the battery cell voltage-capacity curves of the same model sample battery can be matched to the vehicle to be set. Each battery cell voltage-capacity curve is constructed under test environments consisting of different SOH, ambient temperature and discharge rate. By simulating different test environments, the battery cell voltage-capacity curve under each test environment can be constructed.

[0046] S1023. Determine the operating data and use the model information as the second index information. The operating data includes SOH, ambient temperature, and discharge rate.

[0047] S1024. Based on the second index information, match the cell voltage-capacity curve with the same operating data for the vehicle to be set.

[0048] The operating data of the vehicle to be set is used as various environmental parameters in the test environment, namely the SOH, ambient temperature and discharge rate of the test environment, so that the vehicle to be set can match the cell voltage-capacity curve under the same operating data.

[0049] S1025. Using the battery capacity threshold as the third index information, convert the battery capacity threshold into a cell voltage threshold based on the cell voltage-capacity curve under the same operating data.

[0050] Battery capacity threshold As the corresponding battery capacity in the cell voltage-capacity curve, this allows us to find the sample battery discharged to the battery capacity threshold. The corresponding battery voltage at that time is the converted cell voltage threshold. .

[0051] In this embodiment of the invention, step S103 specifically includes: S1031. Determine the real-time cell voltage of each cell in the series-connected battery pack at each moment.

[0052] Assuming the low-voltage battery pack of the vehicle to be configured consists of 12 cells connected in series, the real-time cell voltage of each of the 12 cells is obtained at each moment through various sensors, and the results are obtained accordingly. , … , Indicates the first Energy-saving cells in the first Real-time cell voltage at any given moment.

[0053] S1032. Take the minimum value among all real-time cell voltages at each moment as the corresponding real-time minimum cell voltage. .

[0054] In this embodiment of the invention, considering the worst-case scenario, the minimum value among the real-time cell voltages corresponding to each cell at each moment is selected as the real-time minimum cell voltage. For example, the second cell of the low-voltage battery pack in the... The real-time cell voltage at time t is the minimum among all cells, and the low-voltage battery pack is at the t... Real-time minimum cell voltage at any given moment That is .

[0055] S1033, Determine the real-time minimum cell voltage Less than the cell voltage threshold In the event of this, the parking mode undervoltage protection is triggered and the main circuit breaker is disconnected.

[0056] In this embodiment of the invention, the method may further include the following steps: S201. Obtain the system power consumption after the main circuit breaker of the vehicle to be configured is disconnected, and determine the battery baseline threshold that the vehicle to be configured needs to reserve based on the user-preset system maintenance time and system power consumption. According to the battery reference threshold And a preset gain coefficient, to determine the battery capacity threshold. Specifically:

[0057] in, This indicates the battery capacity threshold, in Ah. This indicates the battery's baseline threshold, expressed in mA / h. This indicates system power consumption, measured in mA / h. This indicates the system uptime, expressed in hours (h). This represents the gain coefficient.

[0058] For example, for a certain vehicle, after the main circuit breaker is disconnected, the system power consumption, including the BMS and low-voltage battery pack self-discharge, is 0.7 mA / h. Assuming the user requires that the remaining charge of the low-voltage battery pack after PM UVP triggering should still be sufficient to sustain the vehicle system operation for 6 months, and the user-preset system sustainment time is 6 months, the battery baseline threshold... The value is: 0.7 6 30 24 / 1000 = 3.024Ah.

[0059] Considering the aging of components in vehicles due to long-term use, possible minor loads, and extreme computational conditions, a battery baseline threshold is established. Multiply by a preset gain factor of 1.12, which is a safety factor, so that when PM UVP is triggered under any operating condition, the low-voltage battery pack will still have at least 3.024 kWh remaining. 1.12 = 3.4Ah of actual usable capacity.

[0060] S202. Based on the constructed cell voltage-capacity curve, set the battery capacity threshold. Converted to cell voltage threshold (Unit: V). Details are as follows: Figure 1 The steps in step S102 are shown in the diagram and will not be described in detail here.

[0061] S203. Determine the real-time minimum cell voltage of the battery pack. In determining the real-time minimum cell voltage Less than the cell voltage threshold In this case, PM UVP is triggered and the main circuit breaker is disconnected. Details are as follows: Figure 1 Step S103 is shown in the diagram and will not be elaborated upon here.

[0062] In this embodiment of the invention, the cell voltage-capacity curve is obtained through the following steps: S301. Place each sample battery with different model information and different SOH under various ambient temperatures, and perform constant current discharge on each sample battery with an initial state of charge of 100% at different discharge rates, and determine the battery voltage and battery capacity of each sample battery during the discharge process.

[0063] Since the discharge performance of battery packs varies at different State of Emergency (SOH), in order to better simulate the discharge process of various battery packs and obtain more reliable and complete discharge data, sample batteries with the same model information at each SOH will be selected for testing. By increasing the amount of sample data, the entire life cycle of the sample battery, various discharge rates, and the temperature range of various driving environments of the vehicle will be covered.

[0064] In this embodiment of the invention, each sample battery can be first charged to its full charge voltage, which is the battery voltage corresponding to a 100% State of Charge (SOC). This ensures that each sample battery is fully charged before constant current discharge. The sample batteries are then placed in different test environments and discharged from their full charge voltage to a cutoff voltage (the battery voltage corresponding to a 0% SOC) using different discharge rates. The battery voltage and capacity of each sample battery during the complete discharge process under different test environments are recorded, and these data are subsequently used to construct a cell voltage-capacity curve.

[0065] It should be noted that the discharge rate is determined by both the discharge current during the discharge process of the sample battery and its nominal rated capacity.

[0066] S302. Based on the battery voltage and battery capacity of the sample batteries, establish the mapping relationship between battery voltage and battery capacity to obtain the cell voltage-capacity curve of each sample battery during the discharge process.

[0067] By obtaining the battery voltage and battery capacity during the complete discharge process of a sample battery, a mapping relationship between the battery voltage and battery capacity during the discharge process can be constructed, thus obtaining the battery voltage mapped to a certain battery capacity.

[0068] S303. Establish the cell voltage-capacity curve and establish the mapping relationship between the cell voltage-capacity curve and model information, SOH and discharge rate.

[0069] The process of establishing the mapping relationship described above can employ mean filtering to ensure stable values ​​at each point. Furthermore, this mapping relationship is established through offline data acquisition in a laboratory environment; that is, it uses sample data from offline testing of the battery samples, and does not rely on online data acquisition. The cell voltage-capacity curves, which establish mapping relationships with model information, SOH, and discharge rate, can all be stored in a pre-set database for easy retrieval of cell voltage thresholds. Retrieve and use at any time.

[0070] For example, first, based on the battery voltage and capacity during the discharge process of sample batteries under different SOH, ambient temperature, and discharge rate, cell voltage-capacity curves of sample batteries are established to obtain cell voltage-capacity curves of the same model of sample batteries under various conditions. Then, the mapping relationship between cell voltage-capacity curves and SOH, ambient temperature, and discharge rate is established to obtain several offline tables of sample batteries of the same model. These offline tables are based on battery capacity thresholds. Using SOH, ambient temperature, and discharge rate as index information, the required cell voltage threshold can be found in the offline table by searching for the dynamic voltage threshold. For example, by conducting the above tests on a sample battery of a certain model, the mapping relationship between battery voltage and battery capacity during the discharge process can be obtained. Based on this mapping relationship, a cell voltage-capacity curve can be constructed, and a battery capacity threshold can be used as the basis for this curve. State of Altitude (SOH), ambient temperature, and discharge rate are used as index information for this curve. For this model of sample battery, a cell voltage-capacity curve can be established for different SOH, ambient temperature, and discharge rate conditions. Each cell voltage-capacity curve is used to retrieve the battery capacity threshold under different SOH, ambient temperature, and discharge rate conditions. The obtained battery voltage can be converted, and offline tables can be constructed under various conditions based on the cell voltage-capacity curve, SOH, ambient temperature, and discharge rate. One offline table can be constructed for each condition.

[0071] The process involves compiling offline tables of sample batteries for all models, then establishing a mapping between these offline tables and the model information. This yields all offline tables, which in turn represent all cell voltage-capacity curves. A dynamic voltage threshold data table is then constructed based on these offline tables, using model information as its index. This dynamic voltage threshold data table can be implemented using a lookup table format to ensure accurate subsequent searches for cell voltage thresholds. It can quickly locate the target.

[0072] like Figures 2 to 5 As shown, Figures 2 to 5 Low-voltage battery packs of a certain type with different state of harm (SOH) in a certain vehicle were discharged to a certain cell voltage threshold. The corresponding offline tables can be retrieved for different SOH (State of Health) levels, i.e., low-voltage battery packs in different battery aging stages. The dynamic voltage thresholds in the offline tables represent the cell voltage thresholds under various conditions. Cell voltage threshold obtained by mapping conversion .

[0073] Figures 2 to 5 The medium temperature refers to the ambient temperature in the test environment, and the current ratio is the discharge ratio in the test environment. Specifically, 100% SOH corresponds to a low-voltage battery pack at the Begin Of Life (BOL) stage, xx1% SOH and xx2% SOH correspond to battery packs at the Middle Of Life (MOL) stage, xx1% is greater than xx2%, and xx3% SOH corresponds to a low-voltage battery pack at the End Of Life (EOL) stage.

[0074] It should be noted that the mapping relationship between battery voltage and battery capacity during the sample battery discharge process can also be displayed by constructing a multi-dimensional matrix, etc. There are no restrictions on the specific form of displaying the mapping relationship between battery voltage and battery capacity during the sample battery discharge process.

[0075] Considering that the actual testing process cannot simulate all test environments and in order to simplify the stored data structure and reduce hardware ROM space, in this embodiment of the invention, the data of the offline table is fitted and calculated by multi-dimensional linear interpolation to simulate more cell voltage-capacity curves under SOH, ambient temperature and discharge rate. That is, dynamic voltage thresholds under more conditions are obtained by fitting the data using multi-dimensional linear interpolation.

[0076] By performing multiple one-dimensional linear interpolations, the cell voltage-capacity curve corresponding to the interpolated environmental parameters can be obtained. Using this multi-dimensional linear interpolation method, while ensuring the accuracy of key data points, software storage space can be effectively saved. This not only makes efficient use of computing resources but also simplifies online calculations and improves the efficiency of BMS software operation.

[0077] The battery capacity threshold will be subsequently determined using the cell voltage-capacity curve. Cell voltage threshold converted to low-voltage battery pack Similarly, multi-dimensional linear interpolation can be used to quickly find the required cell voltage threshold. .

[0078] In this embodiment of the invention, the cell voltage-capacity curve can also be obtained through the following steps: S401. Place each sample battery with different model information and different SOH under various ambient temperatures to determine the initial state of charge of the sample batteries. Perform constant current discharge on each sample battery at different discharge rates and determine the battery voltage and battery capacity of each sample battery during the discharge process.

[0079] Considering that the discharge capacity varies with different initial SOCs, the battery voltage corresponding to a certain battery capacity may also differ depending on the initial SOC. In this embodiment of the invention, the battery voltage and battery capacity of each sample battery will be further tested under various SOH, ambient temperature, and discharge rate conditions based on different initial SOCs.

[0080] S402. Based on the battery voltage and battery capacity of the sample batteries, establish a mapping relationship between battery voltage and battery capacity to obtain the cell voltage-capacity curve of each sample battery during the discharge process. The specific details are as shown in step S202, and will not be repeated here.

[0081] By obtaining the battery voltage and battery capacity during the complete discharge process of a sample battery, a mapping relationship between the battery voltage and battery capacity during the discharge process can be constructed, thus obtaining the battery voltage mapped to a certain battery capacity.

[0082] S403. Establish the cell voltage-capacity curve and establish the mapping relationship between the cell voltage-capacity curve and the initial state of charge, model information, SOH and discharge rate.

[0083] The method for establishing the mapping relationship between the cell voltage-capacity curve and the initial state of charge, model information, SOH and discharge rate is shown in step S203, and will not be repeated here.

[0084] The difference lies in the subsequent search for the cell voltage threshold. The required index entries now include data on the initial state of charge.

[0085] The undervoltage protection device for the battery pack in parking mode provided in the embodiments of the present invention will be described below. The undervoltage protection device for the battery pack in parking mode and the undervoltage protection method for the battery pack in parking mode described below can be referred to each other.

[0086] To address the aforementioned issues, this specification provides an undervoltage protection device for the battery pack in parking mode. This device aims to address the PM UVP requirements themselves, ensuring that the low-voltage battery pack can maintain its power supply for a period of time after the CB is disconnected, thus preventing over-discharge of the low-voltage battery pack. Figure 5 This is a schematic diagram of the undervoltage protection device for the battery pack in parking mode according to an embodiment of the present invention, as shown below. Figure 5 As shown, the device may include: The capacity calculation module 10 is used to obtain the system power consumption after the main circuit breaker of the vehicle to be configured is disconnected, and to determine the battery capacity threshold that the vehicle to be configured needs to reserve based on the user-preset system maintenance time and system power consumption. .

[0087] According to the original requirements of PM UVP, after the circuit breaker CB is disconnected, the remaining power of the vehicle's low-voltage battery pack should be sufficient to sustain the vehicle system for a certain period of time, for example, enough to sustain the vehicle system for 6 months. In this embodiment of the invention, the system power consumption after the main circuit breaker controlling the power supply to the low-voltage battery pack is disconnected is multiplied by the system sustainment time to determine the battery capacity threshold that the battery pack should reserve under normal temperature conditions when the main circuit breaker is disconnected.

[0088] In this embodiment of the invention, the user can set the specific duration of the system maintenance time according to actual usage needs, and can pre-set several baseline maintenance times for user reference. To prevent the system maintenance time set by the user from deviating from actual needs, minimum and maximum maintenance times can also be pre-set, and the system maintenance time set by the user must not exceed the time range constrained by the minimum and maximum maintenance times.

[0089] The system power consumption is obtained by acquiring the power consumption of the BMS and the self-discharge of the low-voltage battery pack within a preset time period, and dividing the power consumption by the duration represented by the preset time period. The system power consumption can be the average power consumption over a period of time.

[0090] The capacity mapping module 20 is used to map the battery capacity threshold based on the constructed cell voltage-capacity curve. Converted to cell voltage threshold The unit is V.

[0091] In this embodiment of the invention, the cell voltage-capacity curve is used to characterize the mapping relationship between battery voltage and battery capacity during the battery pack discharge process. The cell voltage-capacity curve is constructed based on parameters affecting the battery pack discharge performance, such as battery pack model information, ambient temperature, state of equilibrium (SOH), and discharge rate. The cell voltage-capacity curve can be obtained by conducting experiments on sample batteries of the same model as the low-voltage battery pack of the vehicle to be tested, collecting relevant information such as SOH, ambient temperature, and battery voltage, and then establishing the curve based on this information.

[0092] Because the low-voltage battery packs installed on different vehicles have individual differences, in order to meet the PMUVP triggering requirements of different vehicle models, in this embodiment of the invention, the experimental process will select sample battery packs of multiple models, and the cell voltage-capacity curve will include the battery pack model information as a parameter.

[0093] Based on the cell voltage-capacity curve, the mapping relationship between battery voltage and battery capacity can be determined when a sample battery of the same model as the low-voltage battery pack of the vehicle to be tested is discharged under the same SOH, ambient temperature, and discharge rate conditions. Then, based on the mapping relationship between battery voltage and battery capacity, the result can be obtained when the sample battery discharges to the battery capacity threshold under the same SOH, ambient temperature, and conditions. The corresponding battery voltage at that time is the battery capacity of the low-voltage battery pack when discharged to the battery capacity threshold. The corresponding battery voltage at that time is the aforementioned cell voltage threshold. Then, based on the cell voltage-capacity curve, the calculated battery capacity threshold is... Cell voltage threshold converted to low-voltage battery pack .

[0094] Since ambient temperature and State of Harshness (SOH), which characterizes battery aging, both affect the charge and discharge performance of the low-voltage battery pack, and different discharge rates also affect the rate of energy consumption of the low-voltage battery pack, in this embodiment of the invention, the cell voltage-capacity curve is constructed based on the aforementioned parameters affecting the discharge performance of the low-voltage battery pack. By considering the influence of different ambient temperatures, SOH, and discharge rates on the discharge characteristics of the battery pack of the vehicle to be tested, the battery capacity threshold is then determined. Converted to cell voltage threshold Cell voltage threshold Discharge the low-voltage battery pack of the vehicle to be configured to the battery capacity threshold. The corresponding battery voltage at that time. Due to the cell voltage threshold... This parameter is related to the battery capacity threshold. There is a corresponding mapping relationship between SOH, ambient temperature, and discharge rate, therefore the cell voltage threshold... The specific value will depend on the battery capacity threshold. The system adaptively and dynamically adjusts the SOH, ambient temperature, and discharge rate to optimize the cell voltage threshold. It can automatically and continuously adapt to the performance degradation throughout the entire battery life cycle and respond to real-time changes in ambient temperature and load current. This adaptive capability enables the protection strategy to maintain consistent performance throughout the vehicle's entire lifespan and under various geographical and climatic conditions.

[0095] The undervoltage protection module 30 is used to determine the real-time minimum cell voltage of the battery pack. In determining the real-time minimum cell voltage Less than the cell voltage threshold In the event of this, the PM UVP is triggered and the main circuit breaker is disconnected.

[0096] In this embodiment of the invention, the minimum real-time battery cell voltage of the vehicle to be configured is obtained at each moment. The obtained real-time minimum cell voltage The cell voltage threshold obtained by conversion The comparison will be performed, and the minimum real-time cell voltage will be determined at a certain moment. Less than the cell voltage threshold In this case, a PM UVP trigger signal is generated and sent via the Controller Area Network (CAN) bus to notify other controllers in the vehicle, thereby driving the hardware circuit of the vehicle to be configured to disconnect the main circuit breaker of the low-voltage battery pack.

[0097] Specifically, it can save key data each time a PM UVP trigger signal is generated, such as timestamps and real-time minimum cell voltage. Cell voltage threshold Parameters such as SOH and ambient temperature are used for subsequent analysis and optimization of cell voltage-capacity curves.

[0098] At the minimum voltage of the battery cell Less than the cell voltage threshold In the event of this, the PM UVP is triggered and the main circuit breaker is disconnected, using the reserved cell voltage threshold. This ensures that the low-voltage battery pack can maintain the vehicle system's preset operating time even after the main circuit breaker is disconnected, preventing certain systems in the vehicle from lacking power and failing to operate normally after the main circuit breaker is disconnected, and also preventing the low-voltage battery pack from being over-discharged.

[0099] The undervoltage protection device for the battery pack in parking mode of the present invention obtains the system power consumption after the main circuit breaker of the vehicle to be set is disconnected, and determines the battery capacity threshold that the vehicle to be set needs to reserve based on the user-preset system maintenance time and system power consumption. Then, according to the constructed cell voltage-capacity curve, the battery capacity threshold is converted into a cell voltage threshold, so that PM UVP triggering is linked to the actual remaining usable capacity of the battery pack, and does not rely on the state of charge as PM calculated in real time and subject to cumulative error. The direct basis of UVP ensures that, under any battery aging level, temperature, or load conditions, the battery charge remaining in the battery pack before the main circuit breaker disconnects can maintain the vehicle system for the preset system maintenance time. This completely avoids premature or late triggering due to inaccurate SOC estimation or unreasonable fixed thresholds. Furthermore, since the cell voltage threshold parameter has a corresponding mapping relationship with the battery capacity threshold, health status, ambient temperature, and discharge rate, the specific value of the cell voltage threshold will be dynamically adjusted adaptively according to the battery capacity threshold, health status, ambient temperature, and discharge rate. This allows the cell voltage threshold to automatically and continuously adapt to the performance degradation throughout the battery's entire life cycle and respond to real-time changes in ambient temperature and load current. This adaptive capability ensures that the protection strategy maintains consistent performance throughout the vehicle's entire lifespan and under various geographical and climatic conditions. This setting returns to the PM UVP requirement itself, ensuring that the low-voltage battery pack can maintain power supply for a period of time after the CB disconnects, preventing over-discharge of the low-voltage battery pack.

[0100] Figure 7 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 7 As shown, the electronic device may include: a processor 710, a communication interface 720, a memory 730, and a communication bus 740, wherein the processor 710, the communication interface 720, and the memory 730 communicate with each other via the communication bus 740. The processor 710 can call logical commands in the memory 730 to execute an undervoltage protection method for the battery pack in parking mode, the method including: The system power consumption after the main circuit breaker of the vehicle to be configured is disconnected is obtained, and the battery capacity threshold that the vehicle to be configured needs to reserve is determined based on the system maintenance time and system power consumption preset by the user. Based on the constructed cell voltage-capacity curve, the battery capacity threshold is converted into the cell voltage threshold. The cell voltage-capacity curve is used to characterize the mapping relationship between battery voltage and battery capacity during the battery pack discharge process. The cell voltage-capacity curve is constructed based on the battery pack model information, ambient temperature, health status, and discharge rate. Determine the real-time minimum cell voltage of the battery pack. If the real-time minimum cell voltage is less than the cell voltage threshold, trigger the parking mode undervoltage protection and disconnect the main circuit breaker.

[0101] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0102] On the other hand, the present invention also provides a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, wherein when the program instructions are executed by a computer, the computer is able to execute the undervoltage protection method for the battery pack in parking mode provided by the above methods, the method comprising: The system power consumption after the main circuit breaker of the vehicle to be configured is disconnected is obtained, and the battery capacity threshold that the vehicle to be configured needs to reserve is determined based on the system maintenance time and system power consumption preset by the user. Based on the constructed cell voltage-capacity curve, the battery capacity threshold is converted into the cell voltage threshold. The cell voltage-capacity curve is used to characterize the mapping relationship between battery voltage and battery capacity during the battery pack discharge process. The cell voltage-capacity curve is constructed based on the battery pack model information, ambient temperature, health status, and discharge rate. Determine the real-time minimum cell voltage of the battery pack. If the real-time minimum cell voltage is less than the cell voltage threshold, trigger the parking mode undervoltage protection and disconnect the main circuit breaker.

[0103] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0104] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for undervoltage protection of a battery pack in parking mode, characterized in that, The method includes: The system power consumption after the main circuit breaker of the vehicle to be configured is disconnected is obtained, and the battery capacity threshold that the vehicle to be configured needs to reserve is determined based on the system maintenance time and system power consumption preset by the user. Based on the constructed cell voltage-capacity curve, the battery capacity threshold is converted into the cell voltage threshold. The cell voltage-capacity curve is used to characterize the mapping relationship between battery voltage and battery capacity during the battery pack discharge process. The cell voltage-capacity curve is constructed based on the battery pack model information, ambient temperature, health status, and discharge rate. Determine the real-time minimum cell voltage of the battery pack. If the real-time minimum cell voltage is less than the cell voltage threshold, trigger the parking mode undervoltage protection and disconnect the main circuit breaker.

2. The undervoltage protection method for the battery pack in parking mode according to claim 1, characterized in that, The process of converting the battery capacity threshold into a cell voltage threshold based on the constructed cell voltage-capacity curve specifically includes: Determine the battery pack model information and use it as the first index information; Based on the first index information, match the cell voltage-capacity curve of the same model sample battery to the vehicle to be set; Determine the operating data and use the model information as the second index information; the operating data includes health status, ambient temperature, and discharge rate. Based on the second index information, match the cell voltage-capacity curve with the same operating data for the vehicle to be configured; Using the battery capacity threshold as the third index information, the battery capacity threshold is converted into the cell voltage threshold based on the cell voltage-capacity curve under the same operating data.

3. The undervoltage protection method for the battery pack in parking mode according to claim 1, characterized in that, The process of determining the real-time minimum cell voltage of the battery pack, and triggering the parking mode undervoltage protection and disconnecting the main circuit breaker when the real-time minimum cell voltage is determined to be less than the cell voltage threshold, specifically includes: Determine the real-time cell voltage of each cell in the series-connected battery pack at each moment; The minimum value among all real-time cell voltages at each moment is taken as the real-time minimum cell voltage at the corresponding moment. If the real-time minimum cell voltage is determined to be less than the cell voltage threshold, the parking mode undervoltage protection is triggered and the main circuit breaker is disconnected.

4. The undervoltage protection method for the battery pack in parking mode according to claim 1, characterized in that, The cell voltage-capacity curve is constructed in the following manner: Each sample battery with different model information and different health status was placed under various ambient temperatures and constant current discharge was performed on each sample battery with an initial state of charge of 100% at different discharge rates. The battery voltage and battery capacity of each sample battery during the discharge process were determined. Based on the battery voltage and battery capacity of the sample batteries, a mapping relationship between battery voltage and battery capacity is established to obtain the cell voltage-capacity curve of each sample battery during the discharge process. Establish cell voltage-capacity curves and establish the mapping relationship between cell voltage-capacity curves and model information, health status, and discharge rate.

5. The undervoltage protection method for the battery pack in parking mode according to claim 4, characterized in that, The process of establishing a cell voltage-capacity curve and establishing a mapping relationship between the cell voltage-capacity curve and model information, health status, and discharge rate specifically includes: Based on the battery voltage and battery capacity during the discharge process of the sample batteries under different health conditions, ambient temperatures, and discharge rates, cell voltage-capacity curves of the sample batteries were established to obtain cell voltage-capacity curves of the same model of sample batteries under different conditions. Establish the mapping relationship between cell voltage-capacity curves and health status, ambient temperature, and discharge rate to obtain several offline tables for sample batteries of the same model; An offline table compiles sample battery information for all models, and a mapping relationship is established between the offline table and the model information.

6. The undervoltage protection method for the battery pack in parking mode according to claim 1, characterized in that, The cell voltage-capacity curve is constructed in the following manner: Each sample battery with different model information and different health status was placed under various ambient temperatures to determine the initial state of charge of the sample batteries. Each sample battery was subjected to constant current discharge at different discharge rates, and the battery voltage and battery capacity of each sample battery during the discharge process were determined. Based on the battery voltage and battery capacity of the sample batteries, a mapping relationship between battery voltage and battery capacity is established to obtain the cell voltage-capacity curve of each sample battery during the discharge process. Establish cell voltage-capacity curves and establish the mapping relationship between cell voltage-capacity curves and initial state of charge, model information, health status, and discharge rate.

7. The undervoltage protection method for the battery pack in parking mode according to claim 1, characterized in that, The method further includes the following steps: The system power consumption after the main circuit breaker of the vehicle to be configured is disconnected is obtained. Based on the system maintenance time and system power consumption preset by the user, the battery reference threshold that the vehicle to be configured needs to reserve is determined. Based on the battery reference threshold and the preset gain coefficient, the battery capacity threshold is determined.

8. An undervoltage protection device for a battery pack in parking mode, characterized in that, The device includes: The capacity calculation module is used to obtain the system power consumption after the main circuit breaker of the vehicle to be set is disconnected, and to determine the battery capacity threshold that the vehicle to be set needs to reserve based on the system maintenance time and system power consumption preset by the user. The capacity mapping module is used to convert the battery capacity threshold into the cell voltage threshold based on the constructed cell voltage-capacity curve. The cell voltage-capacity curve is used to characterize the mapping relationship between battery voltage and battery capacity during the battery pack discharge process. The cell voltage-capacity curve is constructed based on the battery pack model information, ambient temperature, health status and discharge rate. The undervoltage protection module is used to determine the real-time minimum cell voltage of the battery pack. If the real-time minimum cell voltage is determined to be less than the cell voltage threshold, the parking mode undervoltage protection is triggered and the main circuit circuit breaker is disconnected.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the undervoltage protection method for the battery pack in parking mode as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the undervoltage protection method for the battery pack in parking mode as described in any one of claims 1 to 7.

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