Low voltage battery charging control system and method

Abstract

The application belongs to the technical field of electric vehicles, and discloses a low-voltage battery charging control system and method. Specifically, the system comprises a high-voltage power supply device, a high-voltage conversion device and a low-voltage battery connected in sequence, and a vehicle controller in communication with the low-voltage battery and the high-voltage conversion device. The low-voltage battery detects the current battery state when the vehicle is in a high-voltage state, starts the charging mode when the current battery level is lower than a preset threshold, and sends a charging request according to the current battery state. The vehicle controller sends a voltage control instruction to the high-voltage conversion device in response to the charging request. The high-voltage conversion device converts the high-voltage power distribution output by the high-voltage power supply device and outputs the converted low-voltage power distribution to the low-voltage battery for charging. The charging request voltage is accurately estimated according to the current battery state, so that the low-voltage battery is always in the best charging state, the battery charging efficiency is improved, and the impact of vehicle load fluctuation on the service life of the battery is effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle technology, and in particular to a low-voltage battery charging control system and method. Background Technology

[0002] Current low-voltage battery charging methods generally use a fixed voltage, without considering the impact of battery status and load fluctuations on the charging current. This results in low charging efficiency for low-voltage batteries and also affects their lifespan.

[0003] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The main objective of this invention is to provide a low-voltage battery charging control system and method, which aims to solve the technical problem that existing low-voltage battery charging uses a fixed voltage, resulting in low charging efficiency and affecting battery life.

[0005] To achieve the above objectives, the present invention provides a low-voltage battery charging control system, which includes: a high-voltage power supply device, a high-voltage conversion device, and a low-voltage battery connected in sequence, and a vehicle controller that is communicatively connected to the low-voltage battery and the high-voltage conversion device respectively.

[0006] The low-voltage battery is used to detect the current battery status when the vehicle is in a high-voltage state, and to activate the charging mode when the current battery level is lower than a preset threshold, and to issue a charging request based on the current battery status.

[0007] The vehicle controller is used to send voltage control commands to the high-voltage conversion device in response to the charging request;

[0008] The high-voltage conversion device is used to convert the high-voltage power distribution output by the high-voltage power supply device in response to the voltage control command, and output the converted low-voltage power distribution to the low-voltage battery for charging.

[0009] Optionally, the low-voltage battery is further configured to query the corresponding optimal charging current and optimal voltage based on the current battery state, calculate the output voltage based on the optimal charging current and optimal voltage, and issue a charging request based on the output voltage.

[0010] Optionally, the low-voltage battery charging control system further includes a low-voltage load, and a target connection point is provided on the connection line between the high-voltage conversion device and the low-voltage battery, and the low-voltage load is connected to the target connection point;

[0011] The high-voltage conversion device is also used to supply power to the low-voltage load;

[0012] The low-voltage battery is also used to determine the load current corresponding to the low-voltage load, the first wiring harness resistance between the high-voltage conversion device and the target connection point, and the second wiring harness resistance between the target connection point and the low-voltage battery; calculate a first voltage based on the load current, the optimal charging current and the first wiring harness resistance; calculate a second voltage based on the optimal charging current and the second wiring harness resistance; and calculate an output voltage based on the first voltage, the second voltage and the optimal voltage.

[0013] Optionally, the current battery state includes the current temperature and current charge level, and the low-voltage battery stores different temperatures, different charges, and corresponding optimal charging current and optimal voltage.

[0014] Optionally, the high-voltage conversion device is communicatively connected to the low-voltage battery;

[0015] The high-voltage conversion device is also used to detect the actual output current and actual output voltage of the high-voltage conversion device when the low-voltage battery is in a charging state, and to send the actual output current and actual output voltage of the high-voltage conversion device to the low-voltage battery.

[0016] The low-voltage battery is further configured to, when in a charging state, detect the actual charging current and actual input voltage of the low-voltage battery. When the actual charging current of the low-voltage battery is less than the optimal charging current, the actual output current of the high-voltage conversion device is less than the target output current, and the first current difference is equal to the second current difference, calculate the first wire harness resistivity and the second wire harness resistivity under the current state based on the actual output voltage of the high-voltage conversion device and the actual input voltage of the low-voltage battery. Based on the first wire harness resistivity and the second wire harness resistivity, recalculate the corrected output voltage according to the current state, and issue a charging request based on the corrected output voltage. The first current difference is the current difference between the target output current and the actual output current of the high-voltage conversion device, and the second current difference is the current difference between the optimal charging current and the actual charging current of the low-voltage battery.

[0017] Optionally, the low-voltage battery is further configured to, when the actual charging current of the low-voltage battery is greater than the optimal charging current, the actual output current of the high-voltage conversion device is greater than the target output current, and the third current difference is equal to the fourth current difference, calculate the first wire harness resistivity and the second wire harness resistivity under the current state based on the actual output voltage of the high-voltage conversion device and the actual input voltage of the low-voltage battery; recalculate the corrected output voltage based on the first wire harness resistivity and the second wire harness resistivity according to the current state; and issue a charging request based on the corrected output voltage, wherein the third current difference is the current difference between the actual output current of the high-voltage conversion device and the target output current, and the fourth current difference is the current difference between the actual charging current of the low-voltage battery and the optimal charging current.

[0018] Optionally, the low-voltage battery is further configured to, when the actual charging current of the low-voltage battery is less than the optimal charging current and the actual output current of the high-voltage conversion device is equal to the target output current, calculate the target load current under the current state based on the actual output voltage of the high-voltage conversion device and the actual input voltage of the low-voltage battery, recalculate the corrected output voltage based on the target load current and the current state, and issue a charging request based on the corrected output voltage.

[0019] Optionally, the low-voltage battery is further configured to, when the actual charging current of the low-voltage battery is greater than the optimal charging current and the actual output current of the high-voltage conversion device is equal to the target output current, calculate the target load current under the current state based on the actual output voltage of the high-voltage conversion device and the actual input voltage of the low-voltage battery, recalculate the corrected output voltage based on the target load current and the current state, and issue a charging request based on the corrected output voltage.

[0020] Optionally, the low-voltage battery is also used to send a charging stop request to the vehicle controller when it detects that the current power level has reached the preset threshold.

[0021] The vehicle controller is also used to send a stop charging command to the high-voltage conversion device in response to the charging stop request.

[0022] In addition, to achieve the above objectives, the present invention also proposes a low-voltage battery charging control method, which is applied to the low-voltage battery charging control system described above. The low-voltage battery charging control system includes: a high-voltage power supply device, a high-voltage conversion device, and a low-voltage battery connected in sequence, and a vehicle controller that is communicatively connected to the low-voltage battery and the high-voltage conversion device respectively.

[0023] The low-voltage battery charging control method includes:

[0024] When the vehicle is in a high-voltage state, the low-voltage battery detects the current battery status. When the current battery level is lower than a preset threshold, it starts the charging mode and issues a charging request based on the current battery status.

[0025] The vehicle controller responds to the charging request by sending a voltage control command to the high-voltage conversion device;

[0026] The high-voltage conversion device responds to the voltage control command to convert the high-voltage power distribution output by the high-voltage power supply device, and outputs the converted low-voltage power distribution to the low-voltage battery for charging.

[0027] The low-voltage battery charging control system proposed in this invention includes: a high-voltage power supply device, a high-voltage conversion device, and a low-voltage battery connected in sequence; and a vehicle controller communicatively connected to both the low-voltage battery and the high-voltage conversion device. When the vehicle is in a high-voltage state, the low-voltage battery detects its current battery status. If the current battery level is below a preset threshold, it activates the charging mode and issues a charging request based on the current battery status. The vehicle controller responds to the charging request by sending a voltage control command to the high-voltage conversion device. The high-voltage conversion device responds to the voltage control command by converting the high-voltage power output from the high-voltage power supply device to a low-voltage power output for charging the low-voltage battery. Through this method, the charging request voltage is accurately estimated based on the current battery status, and the output voltage of the high-voltage conversion device is dynamically adjusted, ensuring the low-voltage battery is always in the optimal charging state. This improves battery charging efficiency and effectively avoids the impact of vehicle load fluctuations on battery lifespan. Attached Figure Description

[0028] Figure 1 This is a structural block diagram of the first embodiment of the low-voltage battery charging control system of the present invention;

[0029] Figure 2 This is a schematic diagram showing the relationship between the requested voltage, charging current, and battery capacity of the low-voltage battery charging control system of the present invention.

[0030] Figure 3 This is a block diagram illustrating the low-voltage battery principle of the low-voltage battery charging control system of the present invention.

[0031] Figure 4 This is a structural block diagram of a second embodiment of the low-voltage battery charging control system of the present invention;

[0032] Figure 5 This is a schematic diagram showing the arrangement of the high-voltage conversion device, load, and low-voltage battery in the low-voltage battery charging control system of the present invention.

[0033] Figure 6 This is a structural block diagram of the third embodiment of the low-voltage battery charging control system of the present invention;

[0034] Figure 7 This is a current change curve during the charging process of the low-voltage battery charging control system of the present invention.

[0035] Figure 8 This is a schematic diagram illustrating the specific working process of the low-voltage battery charging control system of the present invention.

[0036] Figure 9 This is a flowchart illustrating the first embodiment of the low-voltage battery charging control method of the present invention.

[0037] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0038] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0039] This invention provides a low-voltage battery charging control method, referring to... Figure 1 , Figure 1 This is a structural block diagram of the first embodiment of the low-voltage battery charging control system of the present invention.

[0040] In this embodiment, the low-voltage battery 30 charging control system includes: a high-voltage power supply device 10, a high-voltage conversion device 20 and a low-voltage battery 30 connected in sequence, and a vehicle controller 40 that is communicatively connected to the low-voltage battery 30 and the high-voltage conversion device 20 respectively.

[0041] The low-voltage battery 30 is used to detect the current battery status when the vehicle is in a high-voltage state, and to activate the charging mode when the current battery level is lower than a preset threshold, and to issue a charging request based on the current battery status.

[0042] It should be understood that the low-voltage battery 30 includes a power supply module, a detection module, a data acquisition module, a communication module, and a control module. The power supply module of the low-voltage battery 30 is mainly used for powering the vehicle load; the detection module is mainly used for real-time monitoring of the low-voltage battery 30's status, specifically for detecting the battery's temperature, voltage, current, etc.; the communication module is mainly used for information exchange with the vehicle controller 40; and the control module is mainly used for controlling the normal on / off switching of the internal relays of the low-voltage battery 30 to achieve normal charging and discharging.

[0043] It should be noted that the low-voltage battery 30 interacts with the vehicle controller 40, driving the vehicle controller 40 to apply high voltage to the entire vehicle. After the vehicle is under high voltage, the vehicle controller 40 feeds back the vehicle status to the low-voltage battery 30. When the vehicle is under high voltage, the low-voltage battery 30 detection module monitors the current battery status in real time, including at least the current battery level. It determines whether the current battery level is below a preset threshold, which is a pre-set critical value used to distinguish whether the battery has reached full charge. If the current battery level is below the preset threshold, it indicates that the battery is not fully charged. At this time, the low-voltage battery 30 control module activates the charging mode, estimates the requested charging voltage based on the current battery status, generates a charging request based on the estimated charging voltage, and sends it to the vehicle controller 40.

[0044] The vehicle controller 40 is used to send voltage control commands to the high-voltage conversion device 20 in response to the charging request.

[0045] It should be understood that when the vehicle controller 40 receives a charging request, it parses the charging request, determines the charging voltage requested by the low-voltage battery 30, generates a voltage control command based on the charging voltage, and sends it to the high-voltage conversion device 20.

[0046] The high-voltage conversion device 20 is used to convert the high-voltage power distribution output by the high-voltage power supply device 10 in response to the voltage control command, and output the converted low-voltage power distribution to the low-voltage battery 30 for charging.

[0047] It should be noted that the high-voltage conversion device 20 includes: a transformer module, a detection module, a communication module, and a control module. The transformer module converts high voltage to low voltage, supplying power to the low-voltage load 50 for normal operation and the low-voltage battery 30 for normal charging. The detection module primarily detects the status of the high-voltage conversion device 20, such as output voltage and output current, facilitating real-time monitoring of the output status by the low-voltage battery 30. The communication module mainly interacts with the vehicle controller 40, enabling real-time monitoring of the high-voltage conversion device 20's status by the vehicle controller 40. The control module primarily controls the output voltage of the high-voltage conversion device 20.

[0048] It should be understood that the high-voltage power supply device 10 is a power battery used to output high-voltage power distribution, and the high-voltage conversion device 20 converts the high voltage to low voltage to output low-voltage power distribution. In specific implementation, the high-voltage conversion device 20 determines the output voltage according to the voltage control command, and the control module of the high-voltage conversion device 20 performs conversion control according to the output voltage, so that the low-voltage power distribution converted by the high-voltage power supply device 10 through the high-voltage conversion device 20 meets the charging needs of the low-voltage battery 30.

[0049] Furthermore, the low-voltage battery 30 is also used to query the corresponding optimal charging current and optimal voltage according to the current battery state, calculate the output voltage according to the optimal charging current and optimal voltage, and issue a charging request according to the output voltage.

[0050] In the specific implementation, a mapping table between battery status, optimal charging current and optimal voltage is stored in advance. The optimal charging current and optimal voltage can be determined by querying the mapping table based on the current battery status. The output voltage of the high voltage conversion device 20 is estimated based on the optimal charging current and optimal voltage, and a charging request is generated based on the output voltage and sent to the vehicle controller 40.

[0051] Optionally, the load voltage and line loss voltage in the power supply circuit are estimated, and the output voltage is determined based on the load voltage, line loss voltage and the optimal voltage, so that the low-voltage power distribution output by the high-voltage conversion device 20 meets the charging requirements of the low-voltage battery 30.

[0052] Specifically, the current battery status includes the current temperature and current charge level, and the low-voltage battery 30 stores different temperatures, different charges, and corresponding optimal charging current and optimal voltage.

[0053] Understandably, based on the cell materials and characteristics selected for the low-voltage battery 30, and taking into account factors such as temperature rise, the optimal charging current and optimal voltage of the low-voltage battery 30 under different states (temperature and charge) are determined through experimental testing. The optimal charging current refers to the maximum allowable charging current of the battery under the current state, representing the best charging state most suitable for the current state, which can extend the battery's lifespan. The optimal voltage refers to the maximum allowable voltage of the battery under the current state, representing the most suitable charging voltage for the battery under the current state, which allows the battery to reach the optimal charging current under the current state.

[0054] like Figure 2 As shown, Figure 2 This is a schematic diagram of the relationship between the requested voltage, charging current and the amount of electricity in the low-voltage battery charging control system of the present invention. At any given moment during the entire charging process, the optimal voltage and optimal charging current corresponding to the amount of electricity are unique. Figure 2 The voltage-to-charge curve shows that the requested voltage increases as the charge increases throughout the charging process. Figure 2 The current-to-charge curves show that in the early stages of charging, the charging current increases with the increase of the charge; in the later stages of charging, the charging current decreases with the increase of the charge.

[0055] Referring to Table 1, which is a schematic diagram of the mapping relationship of the present invention, the table includes two query dimensions: temperature and power. The values ​​stored in the table include voltage value U and current value I. For example, when the current temperature is 25°C and the current power is 85%, the optimal charging current is determined to be I by looking up the table. BAT1 The optimal voltage is U BAT1 .

[0056] Table 1:

[0057]

[0058] Furthermore, the low-voltage battery 30 is also used to send a charging stop request to the vehicle controller 40 when it detects that the current power level has reached the preset threshold.

[0059] The vehicle controller 40 is also used to send a stop charging command to the high-voltage conversion device 20 in response to the charging stop request.

[0060] It should be noted that the low-voltage battery 30 detection module monitors the current battery level in real time. When the current battery level reaches a preset threshold, indicating that the battery is fully charged, a charging stop request is generated and sent to the vehicle controller 40. This causes the vehicle controller 40 to control the high-voltage conversion device 20 to stop supplying low-voltage power to the low-voltage battery 30. In specific implementation, the low-voltage battery 30 estimates the load voltage and line loss voltage, generates the charging stop request based on these voltages, and the vehicle controller 40 controls the output voltage of the high-voltage conversion device 20 to be the sum of the load voltage and the line loss voltage.

[0061] In the specific implementation, refer to Figure 3 , Figure 3 This is a block diagram of the low-voltage battery principle of the low-voltage battery charging control system of the present invention. The internal detection module of the low-voltage battery 30 detects the voltage and current of the low-voltage battery 30 in real time. Based on the detected voltage and current, it determines whether the low-voltage battery 30 is currently in a charging state, thereby evaluating whether the entire charging system is normal.

[0062] The low-voltage battery charging control system proposed in this embodiment includes: a high-voltage power supply device, a high-voltage conversion device, and a low-voltage battery connected in sequence, and a vehicle controller communicatively connected to the low-voltage battery and the high-voltage conversion device respectively. When the vehicle is in a high-voltage state, the low-voltage battery detects its current battery status. If the current battery level is lower than a preset threshold, it activates the charging mode and issues a charging request based on the current battery status. The vehicle controller responds to the charging request and sends a voltage control command to the high-voltage conversion device. The high-voltage conversion device responds to the voltage control command and converts the high-voltage power output from the high-voltage power supply device, outputting the converted low-voltage power to the low-voltage battery for charging. Through this method, the charging request voltage is accurately estimated based on the current battery status, and the output voltage of the high-voltage conversion device is dynamically adjusted, ensuring that the low-voltage battery is always in the optimal charging state, improving battery charging efficiency, and effectively avoiding the impact of vehicle load fluctuations on battery life.

[0063] refer to Figure 4 , Figure 4 This is a structural block diagram of a second embodiment of the low-voltage battery charging control system of the present invention.

[0064] Based on the first embodiment described above, the low-voltage battery 30 charging control system of this embodiment further includes a low-voltage load 50, and a target connection point 60 is provided on the connection line between the high-voltage conversion device 20 and the low-voltage battery 30, and the low-voltage load 50 is connected to the target connection point 60.

[0065] The high-voltage conversion device 20 is also used to supply power to the low-voltage load 50.

[0066] The low-voltage battery 30 is also used to determine the load current corresponding to the low-voltage load 50, the first wiring harness resistance between the high-voltage conversion device 20 and the target connection point 60, and the second wiring harness resistance between the target connection point 60 and the low-voltage battery 30; calculate a first voltage based on the load current, the optimal charging current and the first wiring harness resistance; calculate a second voltage based on the optimal charging current and the second wiring harness resistance; and calculate an output voltage based on the first voltage, the second voltage and the optimal voltage.

[0067] Specifically, the output voltage is calculated using the following formula:

[0068] U AB =(I BAT +∑(I 低压负载 ))R AB ;

[0069] U BD =I BAT R BD ;

[0070] U = UAB +U BD +U BAT ;

[0071] Where, ∑(I 低压负载 ) represents the load current, R AB R is the resistance of the first wire harness. BD For the second wire harness resistor, I BAT For optimal charging current, U AB For the first voltage, U BD For the second voltage, U BAT U is the optimal voltage, and U is the output voltage.

[0072] It should be understood that, optionally, the measured load current, first harness resistance, and second harness resistance can be pre-stored, and the parameters required for calculation can be obtained from the corresponding storage area when calculating the output voltage.

[0073] It should be noted that the first voltage represents the voltage drop of the main trunk wiring harness, and the second voltage represents the voltage drop of the battery terminal wiring harness. (Refer to...) Figure 5 , Figure 5 This is a schematic diagram of the high-voltage conversion device, load, and low-voltage battery arrangement in the low-voltage battery charging control system of the present invention. Target connection point 60 is... Figure 5 At point B in the diagram, assuming time T1, the optimal charging current is found to be I based on the current battery state of low-voltage battery 30. BAT1 The optimal voltage is U BAT1 The voltage drop across the main trunk line (i.e., the voltage across section AB) is U. AB1 The voltage drop across the battery terminal harness (i.e., the voltage in segment BD) is represented by U. BD1 The output voltage U1 is calculated using the following formula:

[0074] U1=U AB1 +U BD1 +U BAT1 .

[0075] Assuming at time T2, the optimal charging current is found to be I based on the current battery state of low-voltage battery 30. BAT2 The optimal voltage is U BAT2 The voltage of segment AB is U AB2 The voltage of segment BD is U BD2 The output voltage U1 is calculated using the following formula:

[0076] U2=U AB2 +U BD2 +U BAT2 .

[0077] Among them, the voltage U in segment AB AB2 for:

[0078] U AB2=I AB2 R AB =(I BAT2 +I BC2 )R AB ;

[0079] Current I in segment BC BC2 for:

[0080] I BC2 =∑(I 低压负载 ) = I bC201 +I BC202 +……+I BC20n ;

[0081] BD segment voltage U BD2 for:

[0082] U BD2 =I AD2 R AB =I BAT2 R BD ;

[0083] Specifically, the resistance of the first wire harness and the resistance of the second wire harness are calculated as follows:

[0084] The resistance of segment BD is:

[0085] R BD =ρ1L BD / S BD ;

[0086] Where ρ1 is the resistivity of the BD segment wire harness; L BD S is the length of the BD harness; BD This represents the cross-sectional area of ​​the BD harness.

[0087] The resistance of segment AB is:

[0088] R AB =ρ2L AB / S AB ;

[0089] Where ρ2 is the resistivity of the AB segment of the wire harness; L AB S is the length of the AB harness; AB Let AB be the cross-sectional area of ​​the wire harness.

[0090] It should be noted that there are a large number of low-voltage loads (50V), and the power consumption of the same load may fluctuate during normal operation. Furthermore, the shutdown of different loads will also cause fluctuations in the overall vehicle power consumption, resulting in variations in the load current I. BC2The voltage fluctuates significantly. By using the above estimation method, the requested output voltage of the low-voltage battery 30 is calculated in real time, and the requested output voltage is always kept at the optimal voltage value so that the low-voltage battery 30 can always be charged with the optimal charging current in the current state, which greatly improves the charging efficiency of the low-voltage battery 30.

[0091] Optionally, the low-voltage battery 30 is further configured to, when detecting a change in charge or a change in temperature, query the change in current and the change in voltage based on the change in charge or the change in temperature, calculate the change in output voltage based on the change in current and the change in voltage, and issue a charging adjustment request based on the change in voltage.

[0092] In one implementation, the low-voltage battery 30 queries a first current and a first voltage based on the charge level and temperature before the change, and queries a second current and a second voltage based on the charge level and temperature after the change. It determines the current change based on the first and second currents, and the voltage change based on the second current and second voltage. The output voltage change is then calculated using the following formula:

[0093] ΔU=I ΔBAT (R AB +R BD )+U ΔBAT .

[0094] Where ΔU is the change in output voltage; I ΔBAT U is the change in current; ΔBAT This represents the change in voltage.

[0095] The vehicle controller 40 sends a charging adjustment request to the vehicle controller 40 based on the voltage change, and the vehicle controller 40 controls the high voltage conversion device 20 to adjust the output voltage according to the charging adjustment request.

[0096] In this embodiment, the output voltage of the charging request is accurately estimated based on the current battery status, load voltage, and wiring harness loss voltage. The output voltage of the high-voltage conversion device is dynamically adjusted so that the low-voltage battery is always in the optimal charging state, which greatly improves the charging efficiency of the low-voltage battery and effectively avoids the impact of vehicle load fluctuations on battery life.

[0097] refer to Figure 6 , Figure 6 This is a structural block diagram of the third embodiment of the low-voltage battery charging control system of the present invention.

[0098] Based on the second embodiment described above, the high-voltage conversion device 20 in this embodiment is communicatively connected to the low-voltage battery 30;

[0099] The high-voltage conversion device 20 is also used to detect the actual output current and actual output voltage of the high-voltage conversion device 20 when the low-voltage battery 30 is in a charging state, and to send the actual output current and actual output voltage of the high-voltage conversion device 20 to the low-voltage battery 30.

[0100] It should be understood that the high-voltage conversion device 20 communicates with the low-voltage battery 30 to determine the state of the low-voltage battery 30 based on the interaction information. When it is determined that the low-voltage battery 30 is in a charging state, the detection module of the high-voltage conversion device 20 detects the actual output current and actual output voltage of the high-voltage conversion device 20 and communicates with the low-voltage battery 30 to send the actual output current and actual output voltage.

[0101] The low-voltage battery 30 is further configured to, when in a charging state, detect the actual charging current and actual input voltage of the low-voltage battery 30. When the actual charging current of the low-voltage battery 30 is less than the optimal charging current, the actual output current of the high-voltage conversion device 20 is less than the target output current, and the first current difference is equal to the second current difference, calculate the first wire harness resistivity and the second wire harness resistivity under the current state based on the actual output voltage of the high-voltage conversion device 20 and the actual input voltage of the low-voltage battery 30. Based on the first wire harness resistivity and the second wire harness resistivity, recalculate the corrected output voltage according to the current state, and issue a charging request based on the corrected output voltage. The first current difference is the current difference between the target output current and the actual output current of the high-voltage conversion device 20, and the second current difference is the current difference between the optimal charging current and the actual charging current of the low-voltage battery 30.

[0102] It should be noted that, referring to Figure 7 , Figure 7 This is a current change curve during the charging process of the low-voltage battery charging control system of the present invention. The actual current during the charging process fluctuates around the target current value under the influence of interference factors. In severe cases, it may exceed the maximum allowable charging current of the low-voltage battery 30, affecting the service life of the low-voltage battery 30.

[0103] In the specific implementation, it is assumed that the actual charging current detected in real time by the low-voltage battery 30 detection module is I. 10 (Optimal charging current is I1), actual input voltage is U 10 (Optimal voltage is U1), the actual output current detected in real time by the detection module of the high-voltage converter 20 is I. A0 The actual output voltage is U A0 Target output current I A The ideal current for the main circuit is calculated based on the optimal charging current and load current: I A =I1+In , among which, I n This is the load current. (Refer to...) Figure 8 , Figure 8 This is a schematic diagram illustrating the specific workflow of the low-voltage battery charging control system of the present invention. The vehicle is in a high-voltage state. The low-voltage battery detection module monitors the battery charge in real time. When the battery charge is less than 100%, the battery starts charging. The low-voltage battery detection module detects the current temperature and charge of the battery and looks up the optimal battery voltage U using a table. BAT and optimal charging current I BAT According to the optimal charging current I BAT Estimate the voltage drop U of the wiring harness on the main road. AB and the voltage drop U of the wiring harness at the battery end BD The control module sends a charging request voltage U, U = U AB +U BD +U BAT The vehicle controller receives a battery charging request voltage U and sends an output voltage command U to the high-voltage converter. Upon receiving the output voltage command, the high-voltage converter outputs voltage U as required. The low-voltage battery begins charging according to the requested voltage U, and the actual charging current I at the battery terminal is monitored in real time by the low-voltage battery detection module. 10 The actual output current I of the main circuit is detected by the high-voltage conversion device's detection module. A0 Based on the monitored data, it can be determined whether the estimation of the wire harness resistivity or the estimation of the load power is inaccurate, and then the estimated parameters and the output voltage of the charging request can be corrected.

[0104] If I 10 <I1 and I A0 <I A And I A -I A0 =I1-I 10 If the charging current is less than the target value, it is determined that the estimated wire harness resistance is too high. The wire harness resistivity ρ will vary slightly due to differences in wire harness temperature and conduction current. In this embodiment, the actual input voltage U of the currently detected low-voltage battery 30 is used as the reference value. 10 And the actual output voltage U of the high voltage converter 20 A0 ,pass:

[0105] U AB =I AB R AB =(I BAT +I BC )R AB =(I BAT +I BC )ρ2L AB / S AB ;as well as

[0106] I BC =∑(I 低压负载 ) = I BC201 +I BC202 +……+I BC20n ;

[0107] The resistivity ρ2 under the current state is derived and calculated, where I BAT That is, I1.

[0108] pass:

[0109] U BD =I BAT R BD =I BAT ρ1L BD / S BD ;

[0110] The resistivity ρ1 under the current state is derived and calculated.

[0111] Based on the derived and calculated actual resistivity and the current state, the requested output voltage under the current state is re-estimated, and a charging request is issued. When the vehicle controller 40 receives the charging request, it sends an output voltage command to the high-voltage conversion device 20, which then outputs the corresponding voltage. Although an overestimation of the wiring harness resistivity will not affect the battery's lifespan, it will affect the charging efficiency of the low-voltage battery 30. Real-time verification and correction can effectively solve the problem of an overestimation of the wiring harness resistivity, thereby improving the charging efficiency of the low-voltage battery 30.

[0112] The low-voltage battery 30 is further configured to, when the actual charging current of the low-voltage battery 30 is greater than the optimal charging current, the actual output current of the high-voltage conversion device 20 is greater than the target output current, and the third current difference is equal to the fourth current difference, calculate the first wire harness resistivity and the second wire harness resistivity under the current state based on the actual output voltage of the high-voltage conversion device 20 and the actual input voltage of the low-voltage battery 30, recalculate the corrected output voltage based on the first wire harness resistivity and the second wire harness resistivity according to the current state, and issue a charging request based on the corrected output voltage, wherein the third current difference is the current difference between the actual output current of the high-voltage conversion device 20 and the target output current, and the fourth current difference is the current difference between the actual charging current of the low-voltage battery 30 and the optimal charging current.

[0113] It should be understood that, with reference Figure 8 , if I 10 >I1 and I A0 >I A And I A0 -I A =I10 If -I1 is detected, the reason for the charging current exceeding the target value is that the estimated wire harness resistance is too low. The wire harness resistivity ρ will vary slightly due to differences in wire harness temperature and conduction current. The actual input voltage U of the currently detected low-voltage battery 30 is then used. 10 And the actual output voltage U of the high voltage converter 20 A0 ,pass:

[0114] U AB =I AB R AB =(I BAT +I BC )R AB =(I BAT +I BC )ρ2L AB / S AB ;as well as

[0115] I BC =∑(I 低压负载 ) = I BC201 +I BC202 +……+I BC20n ;

[0116] The resistivity ρ2 under the current state is derived and calculated, where I BAT That is, I1.

[0117] pass:

[0118] U BD =I BAT R BD =I BAT ρ1L BD / S BD ;

[0119] The resistivity ρ1 under the current state is derived and calculated.

[0120] Based on the derived and calculated actual resistivity and the current state, the requested output voltage under the current state is re-estimated, and a charging request is issued. When the vehicle controller 40 receives the charging request, it sends an output voltage command to the high-voltage conversion device 20, which then outputs the corresponding voltage. Although a lower estimated wire harness resistivity will improve charging efficiency, it will affect the lifespan of the low-voltage battery 30. Real-time verification and correction can effectively solve the problem of an underestimated wire harness resistivity, thereby improving the lifespan of the low-voltage battery 30.

[0121] The low-voltage battery 30 is also used to calculate the target load current under the current state based on the actual output voltage of the high-voltage conversion device 20 and the actual input voltage of the low-voltage battery 30 when the actual charging current is less than the optimal charging current and the actual output current of the high-voltage conversion device 20 is equal to the target output current, recalculate the corrected output voltage based on the target load current and the current state, and issue a charging request based on the corrected output voltage.

[0122] It should be noted that, referring to Figure 8 , if I 10 <I1 and I A0 =I A The reason why the charging current is greater than the target value is that the power consumption estimate at the load end is too low. The load end has a large number of loads, and the power consumption will fluctuate at different times. This is determined by the currently detected actual input voltage U of the low-voltage battery 30. 10 And the actual output voltage U of the high voltage converter 20 A0 ,pass:

[0123] U AB =I AB R AB =(I BAT +I BC )R AB =(I BAT +I BC )ρ2L AB / S AB ;as well as

[0124] I BC =∑(I 低压负载 ) = I BC201 +I BC202 +……+I BC20n ;

[0125] The load-side power consumption in the current state is calculated. Based on the calculated load-side power consumption and the current state, the requested output voltage in the current state is re-estimated, and a charging request is issued. When the vehicle controller 40 receives the charging request, it sends an output voltage command to the high-voltage converter 20, which then outputs the corresponding voltage. Although an underestimation of the load-side power consumption will not affect the battery's lifespan, it will affect the charging efficiency of the low-voltage battery 30. Real-time verification and correction can effectively solve the problem of underestimating the load-side power consumption, thereby improving the charging efficiency of the low-voltage battery 30.

[0126] The low-voltage battery 30 is further configured to, when the actual charging current of the low-voltage battery 30 is greater than the optimal charging current and the actual output current of the high-voltage conversion device 20 is equal to the target output current, calculate the target load current under the current state based on the actual output voltage of the high-voltage conversion device 20 and the actual input voltage of the low-voltage battery 30, recalculate the corrected output voltage based on the target load current and the current state, and issue a charging request based on the corrected output voltage.

[0127] It should be understood that, with reference Figure 8 , if I 10 >I1 and I A0 =I A If the charging current is less than the target value, it is determined that the estimated power consumption at the load end is too high. The load end has a large number of loads, and the power consumption will fluctuate at different times. This is determined by the currently detected actual input voltage U of the low-voltage battery 30. 10 And the actual output voltage U of the high voltage converter 20 A0 ,pass:

[0128] U AB =I AB R AB =(I BAT +I BC )R AB =(I BAT +I BC )ρ2L AB / S AB ;as well as

[0129] I BC =∑(I 低压负载 ) = I BC201 +I BC202 +……+I BC20n ;

[0130] The load-side power consumption in the current state is calculated. Based on the calculated load-side power consumption and the current state, the requested output voltage in the current state is re-estimated, and a charging request is issued. When the vehicle controller 40 receives the charging request, it sends an output voltage command to the high-voltage conversion device 20. Upon receiving the output voltage command, the high-voltage conversion device 20 outputs the corresponding voltage. Although a higher estimated load-side power consumption can improve charging efficiency, it will affect the lifespan of the low-voltage battery 30. Real-time verification and correction can effectively solve the problem of an underestimated load-side power consumption, thereby improving the lifespan of the low-voltage battery 30.

[0131] It should be noted that I 10 =I1andI A0 =I A The low-voltage battery 30 was determined to be in the optimal charging state.

[0132] In this embodiment, by accurately identifying interference factors during the charging process and promptly correcting the output voltage of the charging request, the impact of vehicle load fluctuations and wiring harness resistivity estimation deviations on the output voltage can be effectively avoided. This prevents interference from causing deviations in the charging current value, which would affect the charging efficiency and lifespan of the low-voltage battery, thereby improving the charging stability of the low-voltage battery.

[0133] Reference Figure 9 , Figure 9 This is a flowchart illustrating the first embodiment of the low-voltage battery charging control method of the present invention.

[0134] like Figure 9 As shown, the low-voltage battery charging control method proposed in this embodiment of the invention is applied to the low-voltage battery charging control system described above. The low-voltage battery charging control system includes: a high-voltage power supply device, a high-voltage conversion device, and a low-voltage battery connected in sequence, and a vehicle controller that is communicatively connected to the low-voltage battery and the high-voltage conversion device, respectively.

[0135] The low-voltage battery charging control method includes:

[0136] Step S10: When the vehicle is in a high-voltage state, the low-voltage battery detects the current battery status. When the current battery level is lower than a preset threshold, the charging mode is activated, and a charging request is issued according to the current battery status.

[0137] Step S20: The vehicle controller responds to the charging request by sending a voltage control command to the high-voltage conversion device.

[0138] Step S30: The high-voltage conversion device responds to the voltage control command to convert the high-voltage power distribution output by the high-voltage power supply device, and outputs the converted low-voltage power distribution to the low-voltage battery for charging.

[0139] It should be understood that the above are merely illustrative examples and do not constitute any limitation on the technical solutions of the present invention. In specific applications, those skilled in the art can make settings as needed, and the present invention does not impose any restrictions on this.

[0140] The low-voltage battery charging control system proposed in this embodiment includes: a high-voltage power supply device, a high-voltage conversion device, and a low-voltage battery connected in sequence, and a vehicle controller communicatively connected to the low-voltage battery and the high-voltage conversion device respectively. When the vehicle is in a high-voltage state, the low-voltage battery detects its current battery status. If the current battery level is lower than a preset threshold, it activates the charging mode and issues a charging request based on the current battery status. The vehicle controller responds to the charging request and sends a voltage control command to the high-voltage conversion device. The high-voltage conversion device responds to the voltage control command and converts the high-voltage power output from the high-voltage power supply device, outputting the converted low-voltage power to the low-voltage battery for charging. Through this method, the charging request voltage is accurately estimated based on the current battery status, and the output voltage of the high-voltage conversion device is dynamically adjusted, ensuring that the low-voltage battery is always in the optimal charging state, improving battery charging efficiency, and effectively avoiding the impact of vehicle load fluctuations on battery life.

[0141] It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of this invention. In practical applications, those skilled in the art can select some or all of the workflow to achieve the purpose of this embodiment according to actual needs, and no restrictions are imposed here.

[0142] In addition, for technical details not described in detail in this embodiment, please refer to the low-voltage battery charging control system provided in any embodiment of the present invention, which will not be repeated here.

[0143] In one embodiment, the low-voltage battery issues a charging request based on the current battery state, including:

[0144] The low-voltage battery queries the corresponding optimal charging current and optimal voltage according to the current battery state, calculates the output voltage based on the optimal charging current and optimal voltage, and issues a charging request based on the output voltage.

[0145] In one embodiment, the low-voltage battery charging control system further includes a low-voltage load, and a target connection point is provided on the connection line between the high-voltage conversion device and the low-voltage battery, and the low-voltage load is connected to the target connection point;

[0146] The method further includes:

[0147] The high-voltage conversion device supplies power to the low-voltage load;

[0148] The low-voltage battery calculates its output voltage based on the optimal charging current and the optimal voltage, including:

[0149] The low-voltage battery determines the load current corresponding to the low-voltage load, the first wiring harness resistance between the high-voltage conversion device and the target connection point, and the second wiring harness resistance between the target connection point and the low-voltage battery. It calculates a first voltage based on the load current, the optimal charging current, and the first wiring harness resistance, calculates a second voltage based on the optimal charging current and the second wiring harness resistance, and calculates an output voltage based on the first voltage, the second voltage, and the optimal voltage.

[0150] In one embodiment, the current battery state includes the current temperature and the current charge level, and the low-voltage battery stores different temperatures, different charges, and corresponding optimal charging current and optimal voltage.

[0151] In one embodiment, the high-voltage conversion device is communicatively connected to the low-voltage battery;

[0152] After step S30, the method further includes:

[0153] When the low-voltage battery is in a charging state, the high-voltage conversion device detects the actual output current and actual output voltage of the high-voltage conversion device and sends the actual output current and actual output voltage of the high-voltage conversion device to the low-voltage battery.

[0154] When the low-voltage battery is in a charging state, the actual charging current and actual input voltage of the low-voltage battery are detected. When the actual charging current of the low-voltage battery is less than the optimal charging current, the actual output current of the high-voltage conversion device is less than the target output current, and the first current difference is equal to the second current difference, the first wire harness resistivity and the second wire harness resistivity under the current state are calculated based on the actual output voltage of the high-voltage conversion device and the actual input voltage of the low-voltage battery. Based on the first wire harness resistivity and the second wire harness resistivity, the corrected output voltage is recalculated according to the current state, and a charging request is issued based on the corrected output voltage. Here, the first current difference is the current difference between the target output current and the actual output current of the high-voltage conversion device, and the second current difference is the current difference between the optimal charging current and the actual charging current of the low-voltage battery.

[0155] In one embodiment, after detecting the actual charging current and actual input voltage of the low-voltage battery when the low-voltage battery is in a charging state, the method further includes:

[0156] When the actual charging current of the low-voltage battery is greater than the optimal charging current, the actual output current of the high-voltage converter is greater than the target output current, and the third current difference is equal to the fourth current difference, the low-voltage battery calculates the first and second wire harness resistivity under the current state based on the actual output voltage of the high-voltage converter and the actual input voltage of the low-voltage battery. Based on the first and second wire harness resistivity, the corrected output voltage is recalculated according to the current state, and a charging request is issued based on the corrected output voltage. The third current difference is the current difference between the actual output current of the high-voltage converter and the target output current, and the fourth current difference is the current difference between the actual charging current of the low-voltage battery and the optimal charging current.

[0157] In one embodiment, after detecting the actual charging current and actual input voltage of the low-voltage battery when the low-voltage battery is in a charging state, the method further includes:

[0158] When the actual charging current of the low-voltage battery is less than the optimal charging current and the actual output current of the high-voltage conversion device is equal to the target output current, the low-voltage battery calculates the target load current under the current state based on the actual output voltage of the high-voltage conversion device and the actual input voltage of the low-voltage battery. Based on the target load current, the corrected output voltage is recalculated according to the current state, and a charging request is issued based on the corrected output voltage.

[0159] In one embodiment, after detecting the actual charging current and actual input voltage of the low-voltage battery when the low-voltage battery is in a charging state, the method further includes:

[0160] When the actual charging current of the low-voltage battery is greater than the optimal charging current and the actual output current of the high-voltage conversion device is equal to the target output current, the low-voltage battery calculates the target load current under the current state based on the actual output voltage of the high-voltage conversion device and the actual input voltage of the low-voltage battery. Based on the target load current, the corrected output voltage is recalculated according to the current state, and a charging request is issued based on the corrected output voltage.

[0161] In one embodiment, after step S30, the method further includes:

[0162] When the low-voltage battery detects that the current power level has reached the preset threshold, it sends a charging stop request to the vehicle controller.

[0163] The vehicle controller responds to the charging stop request by sending a stop charging command to the high-voltage conversion device.

[0164] Furthermore, it should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0165] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0166] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as read-only memory (ROM) / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0167] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A low-voltage battery charging control system, characterized in that, The low-voltage battery charging control system includes: a high-voltage power supply device, a high-voltage conversion device, and a low-voltage battery connected in sequence; a vehicle controller that is communicatively connected to the low-voltage battery and the high-voltage conversion device respectively; and a low-voltage load. A target connection point is provided on the connection line between the high-voltage conversion device and the low-voltage battery, and the low-voltage load is connected to the target connection point. The low-voltage battery is used to detect the current battery status when the vehicle is in a high-voltage state, and to activate the charging mode when the current battery level is lower than a preset threshold, and to issue a charging request based on the current battery status. The vehicle controller is used to send voltage control commands to the high-voltage conversion device in response to the charging request; The high-voltage conversion device is used to convert the high-voltage power distribution output by the high-voltage power supply device in response to the voltage control command, and output the converted low-voltage power distribution to the low-voltage battery for charging. The low-voltage battery is also used to query the corresponding optimal charging current and optimal voltage according to the current battery state, calculate the output voltage according to the optimal charging current and optimal voltage, and issue a charging request according to the output voltage; The high-voltage conversion device is also used to supply power to the low-voltage load; The low-voltage battery is also used to determine the load current corresponding to the low-voltage load, the first wire harness resistance between the high-voltage conversion device and the target connection point, the second wire harness resistance between the target connection point and the low-voltage battery, calculate a first voltage based on the load current, the optimal charging current and the first wire harness resistance, calculate a second voltage based on the optimal charging current and the second wire harness resistance, and calculate an output voltage based on the first voltage, the second voltage and the optimal voltage. The low-voltage battery is also used to detect the actual charging current and actual input voltage of the low-voltage battery when it is in a charging state, and to obtain the actual output current and actual output voltage of the high-voltage conversion device. Based on the relationship between the actual charging current, the optimal charging current, the actual output current and the target output current, the first wire harness resistivity and the second wire harness resistivity in the current state are calculated according to the actual output voltage and the actual input voltage. Based on the first wire harness resistivity and the second wire harness resistivity, the corrected output voltage is recalculated according to the current state.

2. The low-voltage battery charging control system as described in claim 1, characterized in that, The current battery status includes the current temperature and current charge level. The low-voltage battery stores different temperatures, different charges, and the corresponding optimal charging current and optimal voltage.

3. The low-voltage battery charging control system as described in claim 1, characterized in that, The high-voltage conversion device is communicatively connected to the low-voltage battery; The high-voltage conversion device is also used to detect the actual output current and actual output voltage of the high-voltage conversion device when the low-voltage battery is in a charging state, and to send the actual output current and actual output voltage of the high-voltage conversion device to the low-voltage battery. The low-voltage battery is further configured to, when in a charging state, detect the actual charging current and actual input voltage of the low-voltage battery. When the actual charging current of the low-voltage battery is less than the optimal charging current, the actual output current of the high-voltage conversion device is less than the target output current, and the first current difference is equal to the second current difference, calculate the first wire harness resistivity and the second wire harness resistivity under the current state based on the actual output voltage of the high-voltage conversion device and the actual input voltage of the low-voltage battery. Based on the first wire harness resistivity and the second wire harness resistivity, recalculate the corrected output voltage according to the current state, and issue a charging request based on the corrected output voltage. The first current difference is the current difference between the target output current and the actual output current of the high-voltage conversion device, and the second current difference is the current difference between the optimal charging current and the actual charging current of the low-voltage battery.

4. The low-voltage battery charging control system as described in claim 3, characterized in that, The low-voltage battery is further configured to, when the actual charging current of the low-voltage battery is greater than the optimal charging current, the actual output current of the high-voltage conversion device is greater than the target output current, and the third current difference is equal to the fourth current difference, calculate the first and second wire harness resistivity under the current state based on the actual output voltage of the high-voltage conversion device and the actual input voltage of the low-voltage battery; recalculate the corrected output voltage based on the first and second wire harness resistivity and the current state; and issue a charging request based on the corrected output voltage. The third current difference is the current difference between the actual output current of the high-voltage conversion device and the target output current, and the fourth current difference is the current difference between the actual charging current of the low-voltage battery and the optimal charging current.

5. The low-voltage battery charging control system as described in claim 3, characterized in that, The low-voltage battery is also used to calculate the target load current under the current state based on the actual output voltage of the high-voltage conversion device and the actual input voltage of the low-voltage battery when the actual charging current of the low-voltage battery is less than the optimal charging current and the actual output current of the high-voltage conversion device is equal to the target output current, recalculate the corrected output voltage based on the target load current and the current state, and issue a charging request based on the corrected output voltage.

6. The low-voltage battery charging control system as described in claim 3, characterized in that, The low-voltage battery is also used to calculate the target load current under the current state based on the actual output voltage of the high-voltage conversion device and the actual input voltage of the low-voltage battery when the actual charging current of the low-voltage battery is greater than the optimal charging current and the actual output current of the high-voltage conversion device is equal to the target output current, recalculate the corrected output voltage based on the target load current and the current state, and issue a charging request based on the corrected output voltage.

7. The low-voltage battery charging control system as described in any one of claims 1-6, characterized in that, The low-voltage battery is also used to send a charging stop request to the vehicle controller when it detects that the current power level has reached the preset threshold. The vehicle controller is also used to send a stop charging command to the high-voltage conversion device in response to the charging stop request.

8. A low-voltage battery charging control method, characterized in that, The low-voltage battery charging control method is applied to the low-voltage battery charging control system as described in any one of claims 1-7. The low-voltage battery charging control system includes: a high-voltage power supply device, a high-voltage conversion device and a low-voltage battery connected in sequence, and a vehicle controller that is communicatively connected to the low-voltage battery and the high-voltage conversion device respectively. The low-voltage battery charging control method includes: When the vehicle is in a high-voltage state, the low-voltage battery detects the current battery status. When the current battery level is lower than a preset threshold, it starts the charging mode and issues a charging request based on the current battery status. Issuing a charging request based on the current battery status includes: the low-voltage battery queries the corresponding optimal charging current and optimal voltage based on the current battery status, calculates the output voltage based on the optimal charging current and optimal voltage, and issues a charging request based on the output voltage. The vehicle controller responds to the charging request by sending a voltage control command to the high-voltage conversion device; The high-voltage conversion device responds to the voltage control command to convert the high-voltage power distribution output by the high-voltage power supply device, and outputs the converted low-voltage power distribution to the low-voltage battery for charging; The step of calculating the output voltage based on the optimal charging current and the optimal voltage includes: the high-voltage conversion device supplying power to the low-voltage load; the low-voltage battery determining the load current corresponding to the low-voltage load, the first wiring harness resistance between the high-voltage conversion device and the target connection point, and the second wiring harness resistance between the target connection point and the low-voltage battery; calculating a first voltage based on the load current, the optimal charging current, and the first wiring harness resistance; calculating a second voltage based on the optimal charging current and the second wiring harness resistance; and calculating the output voltage based on the first voltage, the second voltage, and the optimal voltage. The method further includes: when the low-voltage battery is in a charging state, detecting the actual charging current and actual input voltage of the low-voltage battery, and obtaining the actual output current and actual output voltage of the high-voltage conversion device; based on the relationship between the actual charging current, the optimal charging current, the actual output current, and the target output current, calculating the first wire harness resistivity and the second wire harness resistivity under the current state according to the actual output voltage and the actual input voltage; and recalculating the corrected output voltage based on the first wire harness resistivity and the second wire harness resistivity according to the current state.

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