Intelligent charging control strategy for low-voltage storage battery of electric vehicle

Abstract

The invention provides an intelligent charging control strategy for a low-voltage storage battery of an electric vehicle, and relates to the technical field of electric control of new energy vehicles. According to the invention, the electricity supplementing parameters are dynamically adjusted in combination with the environment temperature, precise electricity supplementing at different environment temperatures is realized, and the electricity supplementing efficiency is improved; excessive charging and insufficient charging are avoided, and damage to the storage battery is reduced, so that the service life of the storage battery is prolonged; stable power supply of the low-voltage storage battery is guaranteed, and the safety and reliability of whole vehicle operation are improved; and the charging requirements in multiple scenes such as low temperature, high temperature and normal temperature are met, and the usability of the electric vehicle in different environments is improved.

Description

Technical Field

[0001] This invention relates to the field of electric control technology for new energy vehicles, and more specifically, to an intelligent charging control strategy for low-voltage batteries in electric vehicles. Background Technology

[0002] With the rapid development of the new energy vehicle industry, electric vehicles have become the core direction for replacing traditional fuel vehicles. Their electrical architecture differs fundamentally from that of traditional fuel vehicles. As the core energy storage component of the vehicle's low-voltage electrical system, the low-voltage battery undertakes key functions such as starting assistance and power supply for onboard electronic devices. Its power supply stability directly affects the safety and reliability of the entire vehicle. Compared to traditional fuel vehicles, electric vehicles' low-voltage batteries are more prone to power depletion. However, electric vehicles have advantages such as high electrical architecture integration, complete energy management system functions, and coordinated control of multiple energy components, making it easier to achieve refined power replenishment control of the low-voltage battery compared to traditional fuel vehicles. Theoretically, electric vehicles can replenish the low-voltage battery through the high-voltage power battery via a DC / DC converter (DC-DC converter). By dynamically adjusting the power replenishment parameters based on the vehicle's operating status and power information, a good hardware foundation and control conditions are provided for optimizing the power replenishment strategy. However, ambient temperature, as a key factor affecting battery performance, significantly alters the state of charge and charge / discharge characteristics of low-voltage batteries. In low-temperature environments, the reaction rate of battery active materials decreases, internal resistance increases, and the actual usable capacity is greatly reduced. Furthermore, the phenomenon of "pseudo-discharge" is prone to occur. Under such conditions, conventional charging strategies may lead to insufficient or excessive charging. In high-temperature environments, the self-discharge rate of batteries accelerates, and prolonged full-charge states can exacerbate battery aging. At the same time, heat accumulation during charging may pose safety risks. Existing charging strategies often employ fixed thresholds or single-parameter control, failing to fully consider the dynamic impact of ambient temperature on the battery's state of charge. This makes it difficult to adapt to the charging needs in various scenarios, including low-temperature, high-temperature, and normal-temperature environments, resulting in problems such as low charging efficiency, significant battery life loss, and insufficient reliability. In summary, given the technical challenges of low-voltage batteries in electric vehicles, such as high risk of battery depletion, significant impact of ambient temperature, and poor adaptability of existing charging strategies, there is an urgent need to develop an intelligent charging control strategy that can dynamically adjust based on ambient temperature. This strategy would fully leverage the advantages of the electric vehicle's electrical architecture, accurately match charging needs in different scenarios, ensure stable power supply to low-voltage batteries, extend battery life, and improve the overall reliability of the vehicle. This has significant practical implications and application value. Summary of the Invention This invention provides an intelligent charging control strategy for low-voltage batteries in electric vehicles, including a timed clock wake-up charging process and an arbitrary wake-up source wake-up backup voltage charging process, wherein: The timer clock wake-up and power replenishment process includes: S1. The controller is woken up by the real-time clock RTC and reads data such as the number of power replenishment cycles, ambient temperature, and battery voltage information. S2. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the voltage threshold, it indicates that there is a need for recharge and the battery needs to be recharged. S3. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the voltage threshold, read the recharge time and lock the recharge time. S4. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the voltage threshold, a network request is made. At this time, a message is sent on the CAN network. The power battery SOC information sent by the BMS is used to determine whether high voltage needs to be applied. When the power battery SOC sent by the BMS is greater than 10%, a request is made to apply high voltage. The arbitrary wake-up source wake-up fallback voltage replenishment process includes: A1. The controller is woken up by any wake-up source and reads the number of power-up cycles, ambient temperature, and battery voltage information. A2. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the backup voltage, it indicates that there is a need for recharge and the battery needs to be recharged. A3. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the fallback voltage, read the recharge time and lock the recharge time. A4. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the fallback voltage, a network request is made. At this time, a message is sent on the CAN network. The power battery SOC information sent by the BMS is used to determine whether high voltage needs to be applied. When the power battery SOC sent by the BMS is greater than 10%, a request is made to apply high voltage.

[0003] As a preferred technical solution of this application, the timer clock wake-up and power replenishment process further includes: S5. No need to replenish power if any of the following conditions are not met: the number of times the power replenishment is less than or equal to the calibrated threshold, the battery voltage is less than or equal to the voltage threshold, or the power battery SOC sent by the BMS is greater than 10%. At this time, the network is released, the controller is allowed to hibernate, and the next RTC wake-up time is written. S6. After requesting high voltage, the controller controls the vehicle to connect to high voltage and enables the DC-DC converter to enter BUCK mode. If the DC-DC converter enters BUCK mode within the calibrated time, the low-voltage battery starts charging. Otherwise, the charging fails, the charging ends, the charging count is incremented by 1, the network is released, the controller is allowed to sleep, and the next RTC wake-up time is written. S7. During the charging process, if the charging time is reached, the charging current is reached, or the power battery SOC is ≤5%, the charging ends, the charging count is incremented by 1, the network is released, the controller is allowed to hibernate, and the next RTC wake-up time is written.

[0004] As a preferred technical solution of this application, the arbitrary wake-up source wake-up backup voltage replenishment process further includes: A5. No need to replenish power if any of the following conditions are not met: the number of times the power replenishment is less than or equal to the calibrated threshold, the battery voltage is less than or equal to the fallback voltage, or the power battery SOC sent by the BMS is greater than 10%. In this case, release the network, allow the controller to hibernate, and write the next RTC wake-up time. A6. After requesting high voltage, the controller controls the vehicle to apply high voltage and enables the DC-DC converter to enter BUCK mode. If the DC-DC converter enters BUCK mode within the calibrated time, the low-voltage battery begins to charge. Otherwise, the charging fails, the charging ends, the charging count is incremented by 1, the network is released, the controller is allowed to sleep, and the next RTC wake-up time is written. A7. During the charging process, if the charging time is reached, the charging current is reached, or the power battery SOC is ≤5%, the charging ends, the charging count is incremented by 1, the network is released, the controller is allowed to hibernate, and the next RTC wake-up time is written.

[0005] Compared with the prior art, the beneficial effects of the present invention are as follows: In the scheme of this application: This application can solve common problems in practical applications such as the high risk of low-voltage battery depletion in electric vehicles, the significant impact of ambient temperature, and the poor adaptability of existing charging strategies. Specific beneficial effects include: 1. Improve charging efficiency: By dynamically adjusting the charging parameters in conjunction with the ambient temperature, precise charging can be achieved under different ambient temperatures, thereby improving charging efficiency; 2. Extend battery life: Avoid overcharging and undercharging to reduce damage to the battery and thus extend its service life; 3. Improve vehicle reliability: Ensure stable power supply from low-voltage batteries, thereby improving the safety and reliability of vehicle operation; 4. Enhanced environmental adaptability: Adapts to charging needs in various scenarios such as low temperature, high temperature, and normal temperature, improving the usability of electric vehicles in different environments. Attached Figure Description

[0006] Figure 1 The flowchart for the timer clock wake-up and power replenishment process provided in this application; Figure 2 A flowchart for providing fallback voltage power replenishment for any wake-up source provided in this application. Detailed Implementation

[0007] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0008] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.

[0009] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0010] For an example, please refer to... Figures 1-2 A smart charging control strategy for low-voltage batteries in electric vehicles includes a timed clock wake-up charging process and an arbitrary wake-up source wake-up fallback voltage charging process. Conventional timed wake-up can meet the charging needs of most idle scenarios, while fallback charging triggered by an arbitrary wake-up source can cover sudden voltage drops within the timed period, avoiding the omission of extreme cases by a single process. The timer clock wake-up and power replenishment process includes: S1. The controller is woken up by the real-time clock (RTC) and reads data such as the number of times the battery was recharged, ambient temperature, and battery voltage. The RTC wake-up method has low power consumption and can continue to work after the vehicle is stopped without consuming too much power. At the same time, by reading three key types of information, namely the number of times the battery was recharged, ambient temperature, and battery voltage, it provides comprehensive data support for subsequent battery recharge decisions and ensures the accuracy of the battery recharge decision. S2. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the voltage threshold, it indicates that there is a need for recharge and the battery needs to be recharged. Too many recharge cycles will lead to frequent charging and discharging of the battery, which will accelerate electrode aging. The voltage threshold is a "critical point for recharge" set based on actual usage needs. The dual conditions can balance the necessity of recharge and the protection of battery life. S3. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the voltage threshold, read the recharge time and lock the recharge time. Locking the recharge time can prevent the recharge duration from getting out of control due to parameter fluctuations during the recharge process, ensuring that the recharge meets the requirements without exceeding them, and at the same time providing a clear basis for the subsequent recharge termination conditions, thus improving the stability of the recharge process. S4. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the voltage threshold, a network request is made. At this time, a message is sent on the CAN network. Based on the power battery SOC information sent by the BMS, it is determined whether high voltage needs to be applied. When the power battery SOC sent by the BMS is greater than 10% (calibrable), a high voltage request is made. The introduction of power battery SOC judgment avoids forced recharge when the power battery is low, protects the power battery from over-discharge damage, and enables efficient communication between the controller and BMS through the CAN network, ensuring timely and accurate SOC information transmission and improving the safety of recharge decision-making. S5. No power replenishment is required if any of the following conditions are not met: the number of power replenishment attempts is less than or equal to the calibrated threshold, the battery voltage is less than or equal to the voltage threshold, or the power battery SOC sent by the BMS is greater than 10% (calibrable). In this case, the network is released, the controller is allowed to hibernate, and the next RTC wake-up time is written. Continuously occupying the network or the controller working when no power replenishment is required will cause invalid energy consumption. Presetting the next wake-up time can ensure that power replenishment monitoring is not interrupted, which saves energy and can respond to subsequent power replenishment needs in a timely manner. S6. After requesting high voltage, the controller controls the vehicle to connect to high voltage and enables the DC-DC converter to enter BUCK mode. If the DC-DC converter enters BUCK mode within the calibrated time, the low-voltage battery begins to charge. Otherwise, the charging fails, the charging ends, the charging count is incremented by 1, the network is released, the controller is allowed to hibernate, and the next RTC wake-up time is written. If the DC-DC converter cannot enter BUCK mode for a long time, continuing to try will waste the power battery and may damage electrical components. Timely termination and status update can avoid the risk from expanding and ensure system stability. S7. During the charging process, if the charging time is reached, the charging current is reached, or the power battery SOC is ≤5% (calibrable), the charging ends, the charging count is incremented by 1, the network is released, the controller is allowed to hibernate, and the next RTC wake-up time is written. Reaching the charging time standard can meet the basic charging requirements, reaching the current standard means that the battery is close to full charge (current decreases), and continuing to charge will lead to overcharging. The power battery SOC ≤5% is the critical value to avoid deep discharge. The combination of the three can cover various risk scenarios during the charging process. The wake-up fallback voltage replenishment process for any wake-up source includes: A1. The controller is woken up by any wake-up source and reads the number of power replenishment times, ambient temperature, and battery voltage information. There is a time interval between timed wake-ups, during which the voltage may drop suddenly due to unexpected power consumption (such as electronic devices not being turned off). Any wake-up source can achieve "real-time monitoring and real-time judgment" to fill the response gap in the timed process. A2. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the backup voltage, it indicates that there is a need for recharge and the battery needs to be recharged. The backup voltage is lower than the normal voltage threshold and is only for the "severe power depletion" scenario. It can prevent recharge from being triggered by slight voltage fluctuations. At the same time, the limit on the number of recharge cycles can prevent the backup recharge from being frequently activated, balancing emergency recharge and battery protection. A3. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the backup voltage, read the recharge time and lock the recharge time. Backup recharge is for emergency scenarios with even lower voltage. If the recharge time is out of control, it may result in insufficient recharge (unable to start the vehicle) or excessive recharge (damage to the battery). Locking the time can ensure the accuracy of emergency recharge. A4. When the number of recharge cycles is less than or equal to the calibrated threshold and the battery voltage is less than or equal to the backup voltage, a network request is made. At this time, a message is sent on the CAN network. The SOC information of the power battery sent by the BMS is used to determine whether high voltage needs to be applied. When the SOC of the power battery sent by the BMS is greater than 10% (calibrable), a high voltage request is made. Although backup recharge is for emergency use, the risk of deep discharge of the power battery still exists. The SOC threshold limit can avoid "saving the low-voltage battery while damaging the high-voltage battery" and ensure the overall safety of the vehicle battery system. A5. No power replenishment is required if any of the following conditions are not met: the number of power replenishment attempts is less than or equal to the calibrated threshold, the battery voltage is less than or equal to the fallback voltage, or the power battery SOC sent by the BMS is greater than 10% (calibrable). In this case, the network is released, the controller is allowed to hibernate, and the next RTC wake-up time is written. If the fallback power replenishment does not meet the start-up conditions, continuous operation is meaningless. Hibernation can save energy, and the preset next wake-up time can ensure that regular monitoring can still be carried out afterward, avoiding the omission of regular power replenishment after emergency scenarios. A6. After requesting high voltage, the controller controls the vehicle to connect to high voltage and enables the DC-DC converter to enter BUCK mode. If the DC-DC converter enters BUCK mode within the calibrated time, the low-voltage battery begins to recharge. Otherwise, the recharge fails, the recharge ends, the recharge count is incremented by 1, the network is released, the controller is allowed to hibernate, and the next RTC wake-up time is written. The risk of DC-DC failure still exists in emergency scenarios. Timely termination of the failure process can avoid wasting the power battery power. Updating the recharge count can prevent repeated attempts in the same fault scenario and protect the electrical system. A7. During the charging process, if the charging time, charging current, or power battery SOC ≤ 5% (calibrable) is detected, the charging ends, the charging count is incremented by 1, the network is released, the controller is allowed to hibernate, and the next RTC wake-up time is written. Here, "charging time reached" means the charging duration has reached the initially locked charging time; "charging current reached" mainly considers that although the charging time has not yet arrived, the battery's charging current is already very small, and charging can be stopped. This strategy is for battery protection, avoiding excessive charging that could affect battery life; "power battery SOC ≤ 5% (calibrable)" mainly considers that the charging process will consume power from the power battery. If too much power is consumed, charging should also stop to avoid the power battery's SOC being too low and still consuming power, thus affecting its lifespan.

[0011] Furthermore, in S2, the calibration threshold for the number of recharge cycles is determined based on actual needs. The number of recharge cycles should not be too many during a single shutdown cycle to avoid affecting the battery's lifespan. The voltage threshold is determined by referring to a table based on the current ambient temperature to achieve recharge under different ambient temperatures. Different batteries (such as lead-acid batteries and lithium batteries) have different cycle life characteristics, and the calibration threshold can be adapted accordingly. Ambient temperature directly affects the battery's voltage-capacity relationship, and the dynamic threshold can correct the interference of temperature on voltage judgment to ensure that the recharge decision is in line with the actual situation.

[0012] Furthermore, in S3, the locked charging time is obtained by looking up a table based on the current battery voltage and ambient temperature. The lower the current battery voltage or ambient temperature, the longer the charging time, so as to achieve the purpose of the longer charging time when the charging demand is higher.

[0013] Furthermore, in S4, the high voltage is requested only when the SOC of the power battery sent by the BMS is greater than 10% (which can be calibrated). This is to ensure that the power battery is charged only when its SOC is relatively sufficient, so as to avoid the power battery being consumed when its SOC is too low, which would affect the life of the power battery.

[0014] Furthermore, in S5, the next RTC wake-up time is obtained by looking up a table based on the current battery voltage and ambient temperature. The principle is that the lower the current battery voltage or ambient temperature, the shorter the next RTC wake-up time, so that it can enter the next RTC wake-up for power replenishment more quickly.

[0015] Furthermore, in S7, the replenishment time reaches the replenishment duration that was initially locked. The reason why the charging current is reached is that although the charging time has not yet arrived, the charging current of the battery is already very small and the charging can be stopped. This strategy is to protect the battery and avoid excessive charging that may affect the battery life. The SOC of the power battery should be ≤5% (can be calibrated) because the power battery will consume power during the charging process. If too much power is consumed, the charging should be stopped to avoid the power battery's lifespan being affected by the continued consumption of power battery power when the SOC is too low.

[0016] Furthermore, in A2, the calibration threshold for the number of recharge cycles is determined based on actual needs. The number of recharge cycles should not be too many during a single shutdown cycle to avoid affecting the battery's lifespan. The backup voltage is determined by referring to a table based on the current ambient temperature. Under the same ambient temperature, the backup voltage is lower than the voltage threshold when the RTC is woken up, so that the power replenishment is only triggered when the battery voltage is indeed very low. The backup voltage power replenishment serves as the last line of defense for the power replenishment function, ensuring that the battery can be replenished in time under various operating conditions as long as it is depleted.

[0017] Furthermore, in A3, the charging time is obtained by looking up a table based on the current battery voltage and ambient temperature. The lower the current battery voltage or ambient temperature, the longer the charging time, so as to achieve the purpose of longer charging time for higher charging demand.

[0018] Furthermore, in A4, it is required that the power battery SOC sent by the BMS be greater than 10% (which can be calibrated) before requesting high voltage. This is to ensure that the power battery is charged only when its SOC is relatively sufficient, so as to avoid the power battery being consumed when its SOC is too low, which would affect the life of the power battery.

[0019] Furthermore, in A5, the next RTC wake-up time is obtained by looking up a table based on the current battery voltage and ambient temperature. The lower the current battery voltage or ambient temperature, the shorter the next RTC wake-up time, thus enabling faster entry into the next RTC wake-up for power replenishment.

[0020] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] Obviously, the embodiments described above are merely some embodiments of the present invention, not all embodiments. The accompanying drawings show preferred embodiments of the present invention, but do not limit the patent scope of the present invention. The present invention can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this invention.

Claims

1. An intelligent control strategy for low-voltage battery charging of an electric vehicle, characterized in that, The method comprises a timing clock wake-up power compensation process and an arbitrary wake-up source wake-up bottom voltage power compensation process, wherein: The timing clock wake-up power compensation process comprises: S1. The controller is woken up by a real-time clock (RTC), and data compensation times, an ambient temperature, and a battery voltage are read; S2. When the compensation times are less than or equal to a calibration threshold value and the battery voltage is less than or equal to a voltage threshold value, it is indicated that power compensation is required, and the battery needs to be compensated for power; S3. When the compensation times are less than or equal to the calibration threshold value and the battery voltage is less than or equal to the voltage threshold value, a compensation time is read and locked; S4. When the compensation times are less than or equal to the calibration threshold value and the battery voltage is less than or equal to the voltage threshold value, a network is requested, at this time, a message is sent on a CAN network, power battery SOC information sent by a BMS is used to determine whether high voltage needs to be applied, and when the power battery SOC sent by the BMS is greater than 10%, the high voltage is requested to be applied; The arbitrary wake-up source wake-up bottom voltage power compensation process comprises: A1. The controller is woken up by an arbitrary wake-up source, and compensation times, an ambient temperature, and a battery voltage are read; A2. When the compensation times are less than or equal to a calibration threshold value and the battery voltage is less than or equal to a bottom voltage, it is indicated that power compensation is required, and the battery needs to be compensated for power; A3. When the compensation times are less than or equal to the calibration threshold value and the battery voltage is less than or equal to the bottom voltage, a compensation time is read and locked; A4. When the compensation times are less than or equal to the calibration threshold value and the battery voltage is less than or equal to the bottom voltage, a network is requested, at this time, a message is sent on a CAN network, power battery SOC information sent by a BMS is used to determine whether high voltage needs to be applied, and when the power battery SOC sent by the BMS is greater than 10%, the high voltage is requested to be applied.

2. The control strategy according to claim 1, wherein, The timing clock wake-up power compensation process further comprises: S5. When any one of the compensation times being less than or equal to the calibration threshold value, the battery voltage being less than or equal to the voltage threshold value, or the power battery SOC sent by the BMS being greater than 10% is not satisfied, power compensation is not required, at this time, the network is released, the controller is allowed to sleep, and a next RTC wake-up time is written; S6. After the high voltage is requested to be applied, the controller controls the vehicle to apply the high voltage and enables a DCDC to enter a BUCK mode, if the DCDC enters the BUCK mode within a calibration time, the low-voltage battery starts to be compensated for power; otherwise, power compensation fails, power compensation ends, the compensation times are increased by 1, the network is released, the controller is allowed to sleep, and the next RTC wake-up time is written; S7. During the power compensation, if it is detected that the compensation time is reached, or the compensation current is reached, or the power battery SOC is less than or equal to 5%, the power compensation ends, the compensation times are increased by 1, the network is released, the controller is allowed to sleep, and the next RTC wake-up time is written.

3. The control strategy according to claim 1, wherein, The arbitrary wake-up source wake-up bottom voltage power compensation process further comprises: A5. When any one of the compensation times being less than or equal to the calibration threshold value, the battery voltage being less than or equal to the bottom voltage, or the power battery SOC sent by the BMS being greater than 10% is not satisfied, power compensation is not required, at this time, the network is released, the controller is allowed to sleep, and a next RTC wake-up time is written; A6, after requesting high voltage, the controller controls the vehicle to high voltage and enables DCDC to enter BUCK mode, if DCDC enters BUCK mode within the calibration time, the low voltage battery starts to charge; otherwise, the charging fails, the charging ends, the charging times increases by 1, the network is released, the controller is allowed to sleep and the next RTC wake-up time is written; A7, during the charging process, if the charging time reaches, or the charging current reaches, or the power battery SOC is less than or equal to 5%, the charging ends, the charging times increases by 1, the network is released, the controller is allowed to sleep and the next RTC wake-up time is written.

4. The control strategy according to claim 1, wherein, In S3, the locked charging time is obtained based on the current battery voltage and the ambient temperature, the lower the current battery voltage or the ambient temperature, the longer the charging time, so as to achieve the purpose of the higher the charging demand, the longer the charging time.

5. The control strategy according to claim 2, wherein, In S5, the next RTC wake-up time written is obtained based on the current battery voltage and the ambient temperature, the principle is the lower the current battery voltage or the ambient temperature, the shorter the next RTC wake-up time written.

6. The control strategy according to claim 2, wherein, In S7, the charging time reaches is that the charging time has reached the locked charging time at the beginning.

7. The control strategy according to claim 1, wherein, In A2, the calibration threshold of the charging times is based on the actual demand; The bottom voltage is determined based on the current ambient temperature, and the bottom voltage is smaller than the voltage threshold of the RTC wake-up time at the same ambient temperature, so as to trigger the charging only when the battery voltage is really small.

8. The control strategy according to claim 1, wherein, In A3, the charging time is obtained based on the current battery voltage and the ambient temperature, the lower the current battery voltage or the ambient temperature, the longer the charging time, so as to achieve the purpose of the higher the charging demand, the longer the charging time.

9. The control strategy according to claim 1, wherein, In A4, the power battery SOC greater than 10% is required to be sent by the BMS before requesting high voltage, in order to charge when the power battery SOC is relatively sufficient.

10. The control strategy according to claim 3, wherein, In A5, the next RTC wake-up time written is obtained based on the current battery voltage and the ambient temperature, the lower the current battery voltage or the ambient temperature, the shorter the next RTC wake-up time written.

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