Battery charging method, device, battery management device and storage medium

Abstract

The present application relates to a battery charging method, device, battery management equipment and storage medium. It includes: when a vehicle is connected to a charging device, the voltage of each battery in the battery pack of the vehicle is obtained, the maximum voltage among the voltages of each battery in the battery pack is determined, and the difference between the voltage of each battery and the maximum voltage is determined to obtain the voltage difference corresponding to each battery; when the battery imbalance of the battery pack is determined according to each voltage difference, the battery pack is grouped according to each voltage difference to obtain at least one battery group, and the difference between the voltages of different batteries in the same battery group is less than or equal to a preset threshold; the battery group is charged according to the charging demand parameters corresponding to the battery group, and the minimum voltage among the voltages of each battery in the battery group during the charging process is determined, and the battery group is charged when the difference between the minimum voltage and the maximum voltage is less than or equal to the preset threshold. This method can reduce resource waste.

Description

Technical Field

[0001] The present application relates to the field of new energy vehicle technology, and in particular to a battery charging method, device, battery management equipment, storage medium and computer program product. Background Art

[0002] At present, the power system of new energy vehicles is provided by battery packs. Since the power and voltage platform of a single battery is low and cannot meet the power requirements of various high-voltage components of the whole vehicle, the power system of new energy vehicles relies on multiple single batteries to form a high-voltage system to provide power requirements for all high-voltage components of the whole vehicle.

[0003] Since the battery system is composed of multiple batteries connected in series or in parallel, it is easy to cause problems with battery capacity consistency. The performance of the entire system will depend on the worst cell, that is, the "barrel effect" of capacity will occur. When charging, the worst cell will reach the cutoff first, and when discharging, it will also reach the cutoff first, resulting in overall capacity attenuation and poor consistency. In severe cases, users will feel a capacity drop. Therefore, in order to maintain battery consistency, the balancing method of the battery system has received more and more attention.

[0004] At present, vehicles mainly rely on passive balancing methods to solve the problem of battery capacity inconsistency. However, since the principle of passive balancing is to discharge batteries with higher voltages and release them in the form of heat energy using resistors, this wastes battery power and causes a waste of resources. Summary of the invention

[0005] Based on this, it is necessary to provide a battery charging method, device, battery management equipment, computer-readable storage medium and computer program product that can reduce resource waste in response to the above technical problems.

[0006] On the one hand, the present application provides a battery charging method, including: when a vehicle is connected to a charging device, obtaining the voltage of each battery in a battery pack of the vehicle, determining the maximum voltage among the voltages of each battery in the battery pack, and determining the difference between the voltage of each battery and the maximum voltage, to obtain a voltage difference corresponding to each battery; in a case where the battery imbalance of the battery pack is determined according to each of the voltage differences, grouping the battery pack according to each of the voltage differences to obtain at least one battery group, wherein the difference between the voltages of different batteries in the same battery group is less than or equal to a preset threshold; for each of the battery groups, determining a charging requirement parameter corresponding to the battery group, charging the battery group according to the charging requirement parameter corresponding to the battery group, and determining the minimum voltage among the voltages of each battery in the battery group during the charging process, and completing the charging of the battery group when the difference between the minimum voltage and the maximum voltage is less than or equal to the preset threshold.

[0007] On the other hand, the present application also provides a battery charging device, including: a voltage difference determination module, which is used to obtain the voltage of each battery in the battery pack of the vehicle when the vehicle is connected to the charging equipment, determine the maximum voltage among the voltages of each battery in the battery pack, and determine the difference between the voltage of each battery and the maximum voltage, so as to obtain the voltage difference corresponding to each battery; a battery grouping module, which is used to group the battery pack according to each voltage difference when the battery imbalance of the battery pack is determined according to each voltage difference, so as to obtain at least one battery group, and the difference between the voltages of different batteries in the same battery group is less than or equal to a preset threshold; a battery charging module, which is used to determine the charging requirement parameters corresponding to each battery group, charge the battery group according to the charging requirement parameters corresponding to the battery group, and determine the minimum voltage among the voltages of each battery in the battery group during the charging process, and complete the charging of the battery group when the difference between the minimum voltage and the maximum voltage is less than or equal to the preset threshold.

[0008] On the other hand, the present application also provides a battery management device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps in the above-mentioned battery charging method when executing the computer program.

[0009] On the other hand, the present application also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps in the above-mentioned battery charging method are implemented.

[0010] On the other hand, the present application also provides a computer program product, including a computer program, which implements the steps in the above-mentioned battery charging method when executed by a processor.

[0011] The battery charging method, device, battery management device, storage medium and computer program product determine the minimum voltage of the voltages of each battery in the battery group during the charging process, and complete the charging of the battery group when the difference between the minimum voltage and the maximum voltage is less than or equal to the preset threshold. Since the difference between the voltages of different batteries in the same battery group is less than or equal to the preset threshold, when the difference between the minimum voltage of the voltages of each battery in the battery group and the maximum voltage of the voltages of each battery in the battery group is less than or equal to the preset threshold, it means that the difference between the voltage of each battery in the battery group and the maximum voltage is less than or equal to the preset threshold, so that the voltage of each battery in the battery group is close to the maximum voltage, so that after the charging of each battery group is completed, the voltage of each battery in the battery group is close to the maximum voltage, and the voltage difference between each battery is less than or equal to the preset threshold. The voltage difference between each battery is less than or equal to the preset threshold, which means that each battery in the battery group is balanced, so that the charging method is adopted to make each battery in the battery group balanced, which reduces resource waste compared to the battery balancing method of discharging. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] FIG1 is an application scenario diagram of a battery charging method in some embodiments;

[0014] FIG2 is a schematic flow chart of a battery charging method in some embodiments;

[0015] FIG3 is a schematic diagram of an OCV-SOC curve in some embodiments;

[0016] FIG4 is a schematic diagram of a DC charging equalization system structure in some embodiments;

[0017] FIG5 is a schematic diagram of an AC charging equalization system structure in some embodiments;

[0018] FIG6 is a schematic diagram of the structure of an AC charging equalization system in some other embodiments;

[0019] FIG7 is a schematic diagram of charging a battery in some embodiments;

[0020] FIG8 is a block diagram of a battery charging device in some embodiments;

[0021] FIG. 9 is a diagram of the internal structure of a battery management device in some embodiments. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] The battery charging method provided in the embodiment of the present application can be applied to the application scenario of Figure 1, which includes a vehicle and a charging device, and the vehicle includes a battery management device, a vehicle control device, a charging circuit and a battery pack. The vehicle can be any vehicle, which can be a passenger car, a bus, a truck or a traction vehicle, etc. It can be a car, a sports utility vehicle, a truck or a bus, a fuel vehicle or a new energy vehicle, an unmanned vehicle, an automatic driving vehicle, a semi-automatic driving vehicle or a non-automatic driving vehicle. The charging device can be an AC charging device or a DC charging device. The AC charging device outputs AC, such as an AC charging pile. The DC charging device outputs DC, such as a DC charging pile.

[0024] Battery management equipment may include equipment for a battery management system (Battery Management System). The battery management system can monitor, manage and maintain the status of the battery pack to ensure safe, efficient and long-life operation of the battery.

[0025] The vehicle control device is used to realize the intelligent control and automation functions of the vehicle. The vehicle control device can be, for example, a VCU (Vehicle Control Unit) in the vehicle. The VCU is responsible for receiving signals from other control modules and performing corresponding operations to realize the intelligent control and automation functions of the vehicle. The battery pack is composed of multiple single cells connected in series. The charging circuit is a circuit used to charge the battery pack. The charging circuit can support AC charging equipment and DC charging equipment. For example, there can be an on-board charging device, namely an on-board charger (OBC), in the charging circuit. The OBC can convert the AC power output by the AC charging pile into the DC power required by the power battery to realize the charging of the power battery. The OBC can communicate with the BMS and the vehicle monitoring system, and dynamically output the current and voltage that are most suitable for the power battery state according to the instructions of the BMS, and select the optimal charging mode for the battery pack. The charging circuit can also include a DC conversion device, namely a DCDC converter. The DCDC converter is a power converter whose main function is to convert a DC (Direct Current) voltage into another DC voltage. The input end of the DC conversion device has positive and negative poles, and the output end also has positive and negative poles.

[0026] Specifically, when the vehicle is connected to the charging device, the battery management device obtains the voltage of each battery in the battery pack of the vehicle, determines the maximum voltage among the voltages of each battery in the battery pack, and determines the difference between the voltage of each battery and the maximum voltage, and obtains the voltage difference corresponding to each battery. In the case of determining that the battery pack is unbalanced according to each voltage difference, the battery management device groups the battery pack according to each voltage difference to obtain at least one battery group, and the difference between the voltages of different batteries in the same battery group is less than or equal to a preset threshold. The battery management device can charge each battery group in turn, and in the process of charging each battery group, determine the charging requirement parameters corresponding to the battery group, charge the battery group according to the charging requirement parameters corresponding to the battery group, and determine the minimum voltage among the voltages of each battery in the battery group during the charging process. When the difference between the minimum voltage and the maximum voltage is less than or equal to the preset threshold, the charging of the battery group is completed. In this way, the batteries in the battery pack can be balanced. The battery charging method provided by this scheme, in principle, uses an external charging method to supplement and balance the batteries with lower voltages. External charging is divided into two forms: DC charging and AC charging. Since the voltage platform of a single battery is relatively low, it is technically difficult to achieve energy supplement for a single battery. Low-voltage batteries can be grouped for low-voltage supplementation until the voltage of this group of batteries is close to the battery with the highest voltage. During DC charging, DC-DC, i.e., DCDC, can be used to convert high voltage into low voltage. During AC charging, when entering the intelligent balancing stage before charging, OBC can be used to output AC power as a lower voltage platform. According to the battery group platform that needs low-voltage supplementation, OBC can adjust the power size of the DC output end in real time, that is, convert AC power into DC power.

[0027] In some embodiments, as shown in FIG2 , a battery charging method is provided, which can be performed by a battery management device, and includes the following steps 202 to 206. Among them:

[0028] Step 202, when the vehicle is connected to the charging device, the voltage of each battery in the battery pack of the vehicle is obtained, the maximum voltage among the voltages of the batteries in the battery pack is determined, and the difference between the voltage of each battery and the maximum voltage is determined to obtain the voltage difference corresponding to each battery.

[0029] Specifically, when the battery management device in the vehicle detects that the charging gun of the charging device is inserted into the charging interface in the vehicle, it is determined that the vehicle is connected to the charging device. There may be at least one of a DC charging interface or an AC charging interface in the vehicle. The DC charging interface is a fast charging interface, which is used to insert the charging gun of the DC charging device, and the AC charging interface is a slow charging interface, which is used to insert the charging gun of the AC charging device.

[0030] In some embodiments, the battery management device can obtain the voltage values ​​of all single cells by sampling the low-voltage battery cells. In this application, the battery refers to a single cell.

[0031] In some embodiments, when there are M batteries in a battery pack, the battery management device can obtain the current voltages of the M batteries, obtain the maximum voltage from the voltages of the M batteries, and then determine the difference between the voltage of the battery and the maximum voltage for each of the M batteries to obtain the voltage difference corresponding to the battery.

[0032] In some embodiments, when the battery management device determines that the vehicle is connected to the charging device, the battery management system can notify the vehicle control device VCU that the vehicle is connected to the charging device, and the vehicle control device VCU determines whether charging is allowed. When it is determined that charging is allowed, an instruction indicating that charging is allowed is returned to the battery management device. When it is determined that charging is not allowed, an instruction indicating that charging is not allowed is returned to the battery management device. The vehicle control device VCU can determine whether charging is allowed based on the current state of the vehicle, or determine whether charging is allowed based on the current state of the battery pack. For example, if the battery pack fails, it is determined that charging is not allowed, otherwise, it is determined that charging is allowed.

[0033] In some embodiments, when the battery management device recognizes a CC2 signal or a CC signal, it can determine whether the vehicle and the charging gun are correctly connected based on the CC2 signal or the CC signal. The CC signal usually appears in slow charging scenarios. The CC signal usually refers to a charging connection confirmation signal, which is used to confirm whether the electrical connection between the charging gun and the vehicle is successful. The CC2 signal usually appears in DC fast charging scenarios, and is similar to the CC signal of slow charging, and is a signal for charging connection confirmation.

[0034] Step 204 , when the battery pack is determined to be unbalanced according to the voltage differences, the battery pack is grouped according to the voltage differences to obtain at least one battery group, wherein the voltage difference between different batteries in the same battery group is less than or equal to a preset threshold.

[0035] Specifically, the preset threshold can be set as needed, for example, 5mv (millivolts). The battery management device can sort the voltage differences in order from large to small or from small to large to obtain a voltage difference sequence, and then divide the voltage difference sequence to obtain multiple voltage difference sub-sequences, and group the batteries corresponding to each voltage difference in the same voltage difference sub-sequence into a battery group. The difference between the maximum voltage difference and the minimum voltage difference in each voltage difference sub-sequence is less than or equal to the preset threshold. For example, if the preset threshold is 5mv, the batteries with a voltage difference in the range of 10mv-15mv can be grouped into one battery group, and the batteries with a voltage difference in the range of 15mv-20mv can be grouped into another battery group.

[0036] Step 206, for each battery group, determine the charging requirement parameters corresponding to the battery group, charge the battery group according to the charging requirement parameters corresponding to the battery group, and determine the minimum voltage among the voltages of each battery in the battery group during the charging process. When the difference between the minimum voltage and the maximum voltage is less than or equal to a preset threshold, the charging of the battery group is completed.

[0037] The charging requirement parameter may include at least one parameter such as voltage or current required for charging.

[0038] Specifically, the battery management device may obtain the remaining capacity of the batteries in the battery group, and determine the charging demand parameters corresponding to the batteries respectively according to the remaining capacity of the batteries in the battery group.

[0039] In some embodiments, the battery management device may control the charging circuit or the charging device to charge the battery group according to the charging requirement parameters corresponding to the battery group.

[0040] In some embodiments, each battery group is charged in sequence. When one battery group is fully charged, the next battery group is charged until all battery groups are fully charged. In the process of charging the battery groups, since the voltage of the batteries in the battery group increases, the battery management device can obtain the voltage of the batteries in the battery group in real time, and compare the minimum voltage of the voltages of the batteries in the battery group with the maximum voltage. If it is determined that the difference between the minimum voltage and the maximum voltage is less than or equal to a preset threshold, the battery group is stopped from being charged. For example, the preset threshold is 5mv, and V max Represents the maximum voltage, V min represents the minimum voltage, then when V max -V minWhen the voltage is less than or equal to 5mv, the battery group is stopped from being charged, and the charging of the battery group is completed. Then, the next battery group is started to be charged until all battery groups are fully charged. Each battery group is charged in sequence, so that the charging process of each battery group does not interfere with each other, thereby improving the charging effect.

[0041] In some embodiments, when all battery groups have completed charging, the battery in the battery pack is balanced, and then the battery management device can charge the battery pack as a whole, thereby completing the charging of the battery pack. Charging the battery pack as a whole can be understood as a normal charging mode. It can be seen that in the entire charging process, there are two stages of charging, the first stage is lower than the balanced charging mode, and the second stage is a normal charging mode. Through two stages of charging, while making the batteries balanced, the charging efficiency is accelerated and resource waste is reduced.

[0042] In the above-mentioned battery charging method, the minimum voltage among the voltages of each battery in the battery group during the charging process is determined, and the charging of the battery group is completed when the difference between the minimum voltage and the maximum voltage is less than or equal to the preset threshold. Since the difference between the voltages of different batteries in the same battery group is less than or equal to the preset threshold, when the difference between the minimum voltage among the voltages of each battery in the battery group and the maximum voltage among the voltages of each battery in the battery group is less than or equal to the preset threshold, it means that the difference between the voltage of each battery in the battery group and the maximum voltage is less than or equal to the preset threshold, so that the voltage of each battery in the battery group is close to the maximum voltage, so that after the charging of each battery group is completed, the voltage of each battery in the battery group is close to the maximum voltage, and the voltage difference between each battery is less than or equal to the preset threshold. The voltage difference between each battery is less than or equal to the preset threshold, which means that each battery in the battery group is balanced, so that the charging method is adopted to make each battery in the battery group balanced, which reduces resource waste compared to the battery balancing method of discharging. That is, compared with passive balancing control (that is, relying on the combination of BMS application layer balancing algorithm and hardware topology structure, BMS obtains the single cell voltage of each battery through battery cell sampling, and then takes the lowest single cell voltage as the benchmark, and actively discharges the single cell voltage that is higher than a certain threshold of the lowest single cell voltage, and the discharge sequence also needs sequential control, such as the balanced MOS switch control, which is generally divided into odd-even sequence control to open. When the high-voltage battery is actively discharged and the lowest voltage battery is less than a certain threshold, the BMS opens the MOS switch of the corresponding battery from the board), it reduces resource waste.

[0043] In some embodiments, determining the charging demand parameters corresponding to the battery grouping includes: determining the maximum remaining capacity ratio from the remaining capacity ratios of each battery in the battery group; determining the minimum remaining capacity ratio from the remaining capacity ratios of each battery in the battery group; determining the difference between the maximum remaining capacity ratio and the minimum remaining capacity ratio to obtain the remaining capacity ratio difference; determining the charging demand parameters corresponding to the battery grouping based on the remaining capacity ratio difference and the rated capacity.

[0044] Among them, the remaining capacity ratio of the battery is the battery SOC. The battery SOC (State of Charge) parameter refers to the battery's state of charge, that is, the available state of the remaining power in the battery. It is the ratio of the remaining capacity of the battery to its fully charged capacity after it has been used for a period of time or has been left unused for a long time, and is usually expressed as a percentage. The SOC value range is 0~1. When SOC=0, it means that the battery is fully discharged, and when SOC=1, it means that the battery is fully charged. The rated capacity refers to the rated capacity of the battery in the battery pack.

[0045] Specifically, the battery management device can calculate the product of the remaining capacity percentage difference and the rated capacity to obtain the difference capacity. max Represents the maximum remaining capacity ratio, using SOC min Represents the minimum remaining capacity ratio, I represents the difference capacity, and C represents the 额定容量 represents the rated capacity, then the difference capacity I=(SOC max -SOC min )×C 额定容量 The battery management device can determine the voltage and current parameters required for charging based on the difference capacity and obtain the charging demand parameters.

[0046] In some embodiments, there is a corresponding relationship between the battery voltage and the battery's remaining capacity percentage, and the battery's remaining capacity percentage can be determined based on the battery voltage. For example, the battery management device can determine the maximum remaining capacity percentage and the minimum remaining capacity percentage based on the OCV-SOC curve. The OCV-SOC curve is a relationship curve between the battery's SOC and the open circuit voltage (OCV). The battery management device can determine the maximum remaining capacity percentage based on the above-mentioned maximum voltage and OCV-SOC curve, and determine the minimum remaining capacity percentage based on the minimum voltage among the voltages of each battery in the battery group and the OCV-SOC curve. For example, with V max Represents the maximum voltage, V min represents the minimum voltage, then SOC max =V max Fitting (OCV-SOC curve), SOC min =V minFitting (OCV-SOC curve). Among them, V max Fitting (OCV-SOC curve) means determining OCV=V from the OCV-SOC curve. max The value of SOC in the case of V min Fitting (OCV-SOC curve) means determining OCV=V from the OCV-SOC curve. min The value of SOC under the condition of .

[0047] Taking the lithium iron phosphate battery as an example, as shown in FIG3, a schematic diagram of the OCV-SOC curve of the lithium iron phosphate battery in some embodiments is provided, the horizontal axis represents SOC, the vertical axis represents the static open circuit voltage, the dotted line represents the measured curve (discrete curve), and the solid line represents the fitting curve (a continuous curve obtained by fitting the discrete curve). Different battery materials may have differences in the OCV-SOC curve. In this embodiment, according to the difference in the remaining capacity ratio and the rated capacity, the charging demand parameters corresponding to the battery grouping can be accurately obtained.

[0048] In some embodiments, each battery in the battery pack belongs to the same battery type, and the remaining capacity ratio of each battery is determined according to the open circuit voltage-remaining capacity ratio curve corresponding to the battery type. The method also includes: determining multiple preset remaining capacity ratios; for each of the preset remaining capacity ratios, using a first voltage test method to determine the open circuit voltage of the test battery when the test battery of the battery type meets the preset remaining capacity ratio, and obtain the first open circuit voltage corresponding to the preset remaining capacity ratio; for each of the preset remaining capacity ratios, using a second voltage test method to determine the open circuit voltage of the test battery when the test battery meets the preset remaining capacity ratio, and obtain the second open circuit voltage corresponding to the preset remaining capacity ratio; for each of the preset remaining capacity ratios, determining the target open circuit voltage corresponding to the preset remaining capacity ratio according to the first open circuit voltage and the second open circuit voltage corresponding to the preset remaining capacity ratio; based on the target open circuit voltages corresponding to each of the preset remaining capacity ratios, generating the open circuit voltage-remaining capacity ratio curve corresponding to the battery type.

[0049] Among them, each battery in the battery pack belongs to the same battery type (can be any battery type, not limited), and the battery type can be divided according to the material of the battery. For the convenience of description, the battery type to which each battery in the battery pack belongs is called the target battery type. The test battery belongs to the target battery type, and the target battery type can be but is not limited to a lithium iron phosphate battery.

[0050] The open circuit voltage-remaining capacity ratio curve is the OCV-SOC curve. The first voltage test method and the second voltage test method are two different methods of generating the OCV-SOC curve. For example, the first voltage test method is the static method, and the second voltage test method is the trickle method. The trickle method uses a smaller current (usually less than C / 20 times) to perform a complete charge and discharge test, where C is the rated capacity.

[0051] Multiple preset remaining capacity ratios can be determined as needed, and the value range of each preset remaining capacity ratio is [0%, 100%]. The test battery meets the preset remaining capacity ratio, which means that the remaining capacity ratio of the test battery is consistent with the preset remaining capacity ratio.

[0052] Specifically, in the process of determining the first open circuit voltage using the first voltage testing method, for each preset remaining capacity ratio, the battery management device can charge and discharge the test battery so that the remaining capacity ratio of the test battery is consistent with the preset remaining capacity ratio, and then, collect the open circuit voltage of the test battery, and use the collected open circuit voltage as the first open circuit voltage corresponding to the preset remaining capacity ratio.

[0053] Similarly, in the process of determining the second open circuit voltage using the second voltage testing method, for each preset remaining capacity ratio, the battery management device can charge and discharge the test battery so that the remaining capacity ratio of the test battery is consistent with the preset remaining capacity ratio, and then, collect the open circuit voltage of the test battery, and use the collected open circuit voltage as the second open circuit voltage corresponding to the preset remaining capacity ratio.

[0054] Although both the first voltage test method and the second voltage test method involve charging and discharging the test battery and collecting the open circuit voltage of the test battery, the charging and discharging are different, or the way or timing of collecting the open circuit voltage is different.

[0055] In some embodiments, for each preset remaining capacity ratio, the battery management device can perform a weighted average of the first open circuit voltage corresponding to the preset remaining capacity ratio and the second open circuit voltage corresponding to the preset remaining capacity ratio, and use the result of the weighted average as the target open circuit voltage corresponding to the preset remaining capacity ratio.

[0056] In some embodiments, the battery management device can generate a discrete OCV-SOC curve based on the target open circuit voltage corresponding to each preset remaining capacity ratio, and the points on the curve are: (SOC=preset remaining capacity ratio, OCV=target open circuit voltage corresponding to each preset remaining capacity ratio). Then, the battery management device can convert the discrete OCV-SOC curve into a continuous OCV-SOC curve. The open circuit voltage-remaining capacity ratio curve corresponding to the battery type is a continuous OCV-SOC curve.

[0057] In this embodiment, the target open circuit voltage corresponding to the preset remaining capacity percentage is determined based on the open circuit voltages obtained by the first voltage testing method and the second voltage testing method respectively, so that the target open circuit voltage can be closer to the actual open circuit voltage, thereby improving the accuracy of the generated open circuit voltage-remaining capacity percentage curve.

[0058] In some embodiments, the first open circuit voltage and the second open circuit voltage are obtained when the test battery is at a specified temperature, and the specified temperature is consistent with the current temperature of the battery pack. The method also includes: determining at least one first type of proportion range and at least one second type of proportion range according to the multiple preset remaining capacity proportions; determining the target open circuit voltage corresponding to the preset remaining capacity proportion according to the first open circuit voltage and the second open circuit voltage corresponding to the preset remaining capacity proportion, including: when the preset remaining capacity proportion belongs to the first type of proportion range, weighted averaging the first open circuit voltage and the second open circuit voltage corresponding to the preset remaining capacity proportion to obtain the target open circuit voltage corresponding to the preset remaining capacity proportion; when the preset remaining capacity proportion belongs to the second type of proportion range, selecting the target open circuit voltage corresponding to the preset remaining capacity proportion from the first open circuit voltage and the second open circuit voltage corresponding to the preset remaining capacity proportion according to the specified temperature.

[0059] Among them, each proportion range is represented by two different preset remaining capacity proportions. For example, if 0% and 25% are two preset remaining capacity proportions, the proportion range is [0%, 25%]. For the open circuit voltage of the test battery determined by the first voltage test method, within the first type of proportion range, the change rate of the open circuit voltage of the test battery is greater than or equal to the preset change rate threshold (which can be an empirical value); and within the second type of proportion range, the change rate of the open circuit voltage of the test battery is less than the change rate threshold. Similarly, for the open circuit voltage of the test battery determined by the second voltage test method, within the first type of proportion range, the change rate of the open circuit voltage of the test battery is greater than or equal to the change rate threshold; and within the second type of proportion range, the change rate of the open circuit voltage of the test battery is less than the change rate threshold. The change rate of the open circuit voltage is used to describe how fast the open circuit voltage changes with SOC. There can be multiple first type proportion ranges, and there can also be multiple second type proportion ranges.

[0060] The above “open circuit voltage-remaining capacity percentage curve corresponding to the battery type” is a curve measured when the test battery is at a specified temperature. The specified temperature is consistent with the current temperature of the battery pack. The temperature of the battery can be the temperature of the battery itself or the temperature of the environment surrounding the battery.

[0061] Specifically, if the change rate of the open circuit voltage is greater than or equal to the preset change rate threshold, it can be understood that the open circuit voltage changes rapidly (non-steady change), and if the change rate of the open circuit voltage is less than the change rate threshold, it can be understood that the open circuit voltage changes steadily. In the case of steady change, the change of the open circuit voltage is greatly affected by temperature; in the case of non-steady change, the change of the open circuit voltage is mainly affected by the test method (first voltage test method, second voltage test method).

[0062] Therefore, if the preset remaining capacity ratio belongs to the first type of ratio range, it indicates that the open circuit voltage at the preset remaining capacity ratio is in a non-steady change. Therefore, the target open circuit voltage is determined by taking a weighted average of the first open circuit voltage and the second open circuit voltage. This can reduce the error caused by the test and improve the accuracy of the target open circuit voltage.

[0063] If the preset remaining capacity ratio belongs to the second type of ratio range, it indicates that the open circuit voltage at the preset remaining capacity ratio is in a stable change, so that the target open circuit voltage is selected from the first open circuit voltage and the second open circuit voltage according to the specified temperature, which can reduce the error caused by the temperature and improve the accuracy of the target open circuit voltage. Since the battery voltage is usually higher at a higher temperature, if the specified temperature is greater than or equal to the preset temperature threshold (which can be determined based on experience), the larger of the first open circuit voltage and the second open circuit voltage can be used as the target open circuit voltage; if the specified temperature is less than the temperature threshold, the smaller of the first open circuit voltage and the second open circuit voltage can be used as the target open circuit voltage.

[0064] In this embodiment, for the preset remaining capacity proportions in the proportion ranges belonging to different types, an adaptive method is adopted to reduce the error and determine the target open circuit voltage, thereby improving the accuracy of the open circuit voltage.

[0065] In some embodiments, when determining that the batteries in a battery pack are unbalanced based on each voltage difference value, the battery pack is grouped according to each voltage difference value to obtain at least one battery group, including: counting the number of voltage difference values ​​that are greater than a voltage difference threshold value among each voltage difference value to obtain a target number; when the target number reaches a preset number threshold, determining that the batteries in the battery pack are unbalanced, and grouping the battery pack according to each voltage difference value to obtain at least one battery group.

[0066] Specifically, the voltage difference threshold can be pre-set as needed, and the voltage difference threshold is, for example, 10mv. The quantity threshold can be set as needed, for example, N, where N is greater than or equal to 1. The data threshold can also be determined based on the minimum output power of the OBC or DCDC, or can be calculated by investigating relevant data. For the M battery differences obtained above, if there are N or more battery differences among the M battery differences that are greater than the voltage difference threshold, for example, 10mv, it is determined that the batteries in the battery pack are unbalanced.

[0067] Since the charging of the battery group is completed when the difference between the minimum voltage and the maximum voltage is less than or equal to the preset threshold, it means that after charging the batteries in the battery group, the voltage of the batteries in the battery group will not exceed the determined maximum voltage, and the maximum voltage is the maximum voltage before charging the entire battery pack, so the maximum voltage is relatively low, so charging the battery group can be understood as low-voltage charging. Furthermore, since the purpose of charging the battery group is to reduce the voltage difference between the batteries in the battery group, that is, to reduce the capacity gap between the batteries in the battery group, so that the batteries in the battery group are as balanced as possible, charging the battery group can be further understood as a charging method of a low-voltage charging equalization mode. The target number reaches the preset number threshold, which can be understood as satisfying one of the conditions for entering the low-voltage charging equalization mode.

[0068] In this embodiment, when the target number reaches a preset number threshold, it is determined that the batteries of the battery pack are unbalanced, thereby improving the accuracy of determining the battery unbalance.

[0069] In some embodiments, the charging device is a DC charging device, and the battery charging method provided in the present application may be based on a DC charging system, as shown in FIG4 , which shows a schematic diagram of the structure of a DC charging system. In FIG4 , the batteries in the battery pack are combined in series, the positive electrode of the battery pack is connected to the positive electrode of the DC charging device through a first positive relay, the negative electrode of the battery pack is connected to the negative electrode of the DC charging device through a first negative relay, the positive electrode of the DC charging device is connected to the input positive electrode of the DC conversion device in the vehicle through a second positive relay, and the negative electrode of the DC charging device is connected to the input negative electrode of the DC conversion device through a second negative relay. For each battery in the battery pack, the positive electrode of the battery is connected to the output positive electrode of the DC conversion device through a corresponding first semiconductor switch, and the negative electrode of the battery is connected to the output negative electrode of the DC conversion device through a corresponding second semiconductor switch.

[0070] Among them, the battery pack is B in Figure 4 1 -B n The positive pole of the battery pack is B. 1 The positive electrode of the battery pack is the negative electrode of battery B. nThe input positive pole of the DC conversion device is the positive pole of the input terminal of the DC conversion device, and the input negative pole of the DC conversion device is the negative pole of the input terminal of the DC conversion device. The output positive pole of the DC conversion device is the positive pole of the output terminal of the DC conversion device, and the output negative pole of the DC conversion device is the negative pole of the output terminal of the DC conversion device. The DC conversion device receives the current input by the DC charging device and outputs the current to the battery pack to charge the battery pack.

[0071] The positive electrode of each battery corresponds to its own first semiconductor switch, and the negative electrode of each battery corresponds to its own second semiconductor switch. The first semiconductor switch corresponding to the positive electrode of the battery is a semiconductor switch on the line from the positive electrode of the battery to the positive electrode of the DC conversion device. When the first semiconductor switch is closed, the positive electrode of the battery is connected to the positive electrode of the DC conversion device. Similarly, the second semiconductor switch corresponding to the negative electrode of the battery is a semiconductor switch on the line from the negative electrode of the battery to the negative electrode of the DC conversion device. When the second semiconductor switch is closed, the negative electrode of the battery is connected to the negative electrode of the DC conversion device. The semiconductor switch is, for example, a MOS (metal oxide semiconductor field effect transistor) switch. In FIG. 4, C 1 -C n+1 is the first semiconductor switch, D 1 -D n+1 is the second semiconductor switch.

[0072] Specifically, each battery group is charged in sequence. Before charging each battery group, the battery management device can also control the first positive relay to open and the second positive relay to close. In order to charge the battery group according to the charging requirement parameters corresponding to the battery group, the battery management device can control the first semiconductor switch and the second semiconductor switch corresponding to each battery in the battery group to close, and control the first semiconductor switch and the second semiconductor switch corresponding to the remaining batteries in the battery group to open (if the first semiconductor switch and the second semiconductor switch corresponding to the remaining batteries are already in the disconnected state, there is no need to control the disconnection), and send the charging requirement parameters corresponding to the battery group to the DC charging device, so that the DC charging device charges the battery group according to the charging requirement parameters corresponding to the battery group. For example, if B 1 and B 3 To form a battery group, when B 1 and B 3 When the battery group is charged at low voltage, the B 1 The positive electrode corresponds to C 1 , B 1 The negative pole corresponds to D 2 , B 3 The positive electrode corresponds to C 3 , B 3 The negative pole corresponds to D 4, so the battery management device can close C 1 and D 2 , and close C 3 and D 4 , so that B 1 and B 3 Form a parallel circuit to 1 and B 3 The remaining batteries in the battery pack refer to batteries other than the batteries in the battery pack being charged.

[0073] In some embodiments, the battery management device may control the first semiconductor switch and the second semiconductor switch to close before, at the same time, or after sending the charging requirement parameters corresponding to the battery group to the DC charging device. The battery management device may send the charging requirement parameters to the DC charging device by sending a BCL (Battery Charger Link) message. The BCL message carries the charging requirement parameters.

[0074] In this embodiment, the DC charging system can be used to charge the battery packs in groups, thereby improving the balance of the batteries in the battery pack.

[0075] In some embodiments, when the last battery group stops charging, the second positive relay is controlled to be disconnected, and the first positive relay is controlled to be closed, so that the battery pack as a whole is charged using a DC charging device. Specifically, when the last battery group stops charging, the second negative relay can also be controlled to be disconnected, and the first negative relay can be controlled to be closed. As shown in FIG. 4 , when the second positive relay and the second negative relay are in an open state, and the first negative relay and the first positive relay are in a closed state, the DC charging device can be used to charge the batteries in series at the same time.

[0076] In some embodiments, the battery management device can control the opening and closing of the relay through the VCU. For example, when receiving the charging permission instruction sent by the VCU and determining that the batteries of the battery pack are unbalanced, the battery management device can send a balanced charging instruction to the VCU so that the VCU controls the second positive relay to close.

[0077] In this embodiment, the DC charging system can first improve the balance of the battery, and then charge the battery pack as a whole on this basis, thereby improving the charging effect of the battery pack.

[0078] In some embodiments, the charging device is an AC charging device, and the battery charging method provided in the present application may be based on an AC charging system, as shown in FIG5 , which shows a schematic diagram of the structure of an AC charging system. In FIG5 , the batteries in the battery pack are combined in series, the positive electrode of the AC charging device is connected to the input positive electrode of the on-board charging device in the vehicle through the third positive relay, the negative electrode of the AC charging device is connected to the input negative electrode of the on-board charging device through the third negative relay, the positive electrode of the battery pack is connected to the output positive electrode of the on-board charging device through the fourth positive relay, and the negative electrode of the battery pack is connected to the output negative electrode of the on-board charging device through the fourth negative relay. For each battery in the battery pack, the positive electrode of the battery is connected to the output positive electrode of the on-board charging device through the corresponding first semiconductor switch, and the negative electrode of the battery is connected to the output negative electrode of the on-board charging device through the corresponding second semiconductor switch.

[0079] Among them, the input positive pole of the on-board charging device refers to the positive pole of the input end of the on-board charging device, and the input negative pole of the on-board charging device refers to the negative pole of the input end of the on-board charging device. The output positive pole of the on-board charging device refers to the positive pole of the output end of the on-board charging device, and the output negative pole of the on-board charging device refers to the negative pole of the output end of the on-board charging device.

[0080] Specifically, each battery group is charged in sequence, and before charging each battery group, the battery management device can control the fourth positive relay to be disconnected and the third positive relay to be closed. In order to charge the battery group according to the charging requirement parameters corresponding to the battery group, the battery management device can control the first semiconductor switch and the second semiconductor switch corresponding to each battery in the battery group to be closed, control the first semiconductor switch and the second semiconductor switch corresponding to the remaining batteries in the battery group to be disconnected, and send the charging requirement parameters corresponding to the battery group to the on-board charging device, so that the on-board charging device charges the battery group according to the charging requirement parameters corresponding to the battery group.

[0081] In some embodiments, the battery management device may control the first semiconductor switch and the second semiconductor switch to close before, simultaneously with, or after sending the charging requirement parameter corresponding to the battery group to the on-board charging device.

[0082] In FIG5 , the two charging stages share a vehicle-mounted charging device. Of course, different vehicle-mounted charging devices can be used in the two charging stages. As shown in FIG6 , a structural schematic diagram of another AC charging system is shown. In FIG6 , the AC charging device is connected to two independent vehicle-mounted charging devices, namely, a first vehicle-mounted charging device and a second vehicle-mounted charging device. The battery charging method provided in the present application can be based on the AC charging system in FIG6 .

[0083] In this embodiment, the battery packs can be charged in groups through the AC charging system, thereby improving the balance of the batteries in the battery pack, improving the consistency of the batteries, and protecting the health of the batteries.

[0084] In some embodiments, controlling the third positive relay to close includes: upon receiving a charging permission instruction sent by the vehicle control device and determining that the batteries in the battery pack are unbalanced, sending a balanced charging instruction to the vehicle control device so that the vehicle control device controls the third positive relay to close.

[0085] Specifically, when the last battery group stops charging, the battery management device can control the fourth positive relay to close so as to charge the entire battery pack using the on-board charging device. During the charging of the entire battery pack, each first semiconductor switch and each second semiconductor switch are in an open state.

[0086] In this embodiment, when a charging permission instruction is received from the vehicle control device and it is determined that the batteries in the battery pack are unbalanced, a balanced charging instruction is sent to the vehicle control device so that the vehicle control device controls the third positive relay to close, so that charging can be carried out while ensuring that charging is permitted, thereby ensuring the safety of charging.

[0087] As shown in Figure 7, a schematic diagram of charging the battery is provided. For BMS, VCU, OBC or DCDC, when a wake-up signal triggered by hardware wake-up or network management wake-up is detected, initialization is performed and it is determined whether the initialization is successful. After the BMS is successfully initialized, when the charging gun is inserted into the vehicle, it is determined whether it is in AC charging mode or DC charging mode, and the result of the judgment is sent to the VCU. After receiving the result of the judgment, the VCU determines whether to send a charging permission instruction. If so, a charging permission instruction is sent to the BMS. If not, a charging prohibition instruction is sent to the BMS.

[0088] When the BMS receives the instruction to allow charging, it determines whether to enter the low-voltage charging equalization stage (i.e., the group charging stage). If it is determined that the battery does not need to be equalized, it further determines whether there is no preset mode, and in the absence of a preset mode, it determines whether it is necessary to enter the normal charging stage (normal AC / DC charging stage). If so, it can enter the normal charging stage, and in the normal charging stage, it can determine whether it is full or charging is prohibited due to a fault. If so, the BMS ends charging and enters the dormant state without other requirements. If it is determined that the battery needs to be equalized, an instruction to enter the low-voltage charging equalization stage is sent to the VCU. When the VCU determines that it is necessary to enter the low-voltage charging equalization stage, it sends an instruction to close the corresponding relay to the OBC or DCDC. When the VCU determines that it does not need to enter the low-voltage charging equalization stage, it determines whether it is full or charging is prohibited for the entire vehicle. If so, it sends an instruction to the BMS that charging is not allowed. After entering the low-voltage charging equalization stage, the BMS can determine in real time whether the low-voltage charging equalization stage is over, and in the case of DC charging, it sends a BCL message to the DC charging pile, and the BCL message carries the charging demand parameters.

[0089] After the OBC or DCDC is successfully initialized, when it receives the enable command sent by the VCU, the OBC or DCDC enters the working state. After determining that it has entered the working state, if it receives the command sent by the VCU to disconnect its relay, it enters the sleep state.

[0090] In some embodiments, when the vehicle is connected to a DC charging gun, the BMS identifies the charging gun, and the VCU determines whether the vehicle status allows charging at this time, and then sends it to the BMS through a CAN message. After the BMS recognizes the VCU permission instruction, it starts to exchange messages with the charging pile, and finally during charging, the BMS sends the charging voltage and charging current requirements to the charging pile through a message. When fully charged, the BMS sends a BST stop message and finally stops the charging process. When the BMS detects that it is necessary to enter the low-voltage charging balancing stage, the fast charging positive relay (the relay connected to the positive pole of the DC charging pile) is disconnected during charging, and the relay of the DCDC corresponding circuit is closed. Then, the charging requirement voltage and current of the low-voltage charging balancing stage are sent through the BMS. According to the corresponding low-voltage charging balancing stage BMS strategy, the MOS switch on the corresponding balancing topology structure is controlled to be closed, thereby forming a corresponding balancing charging circuit. A balancing charging circuit refers to a circuit for charging battery groups.

[0091] In some embodiments, when the BMS recognizes that the AC charging gun is connected, it enters the AC charging stage. If the BMS recognizes that it needs to enter the low-voltage charging equalization stage, it controls the main positive relay (such as the fourth positive relay mentioned above) to disconnect, and the OBC converts the required voltage of the low-voltage charging equalization stage and inputs it to the entire equalization charging circuit. It also controls the MOS switch according to the corresponding charging equalization stage strategy to allow the single battery to be equalized. The battery charging method provided by this application helps to standardize the functions of the industry algorithm software and is easier to upgrade and iterate.

[0092] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0093] Based on the same inventive concept, the embodiment of the present application also provides a battery charging device for implementing the battery charging method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more battery charging device embodiments provided below can refer to the limitations on the battery charging method above, and will not be repeated here.

[0094] In some embodiments, as shown in FIG. 8 , a battery charging device is provided, including: a voltage difference determination module 802 , a battery grouping module 804 , and a battery charging module 806 , wherein:

[0095] The voltage difference determination module 802 is used to obtain the voltage of each battery in the battery pack of the vehicle when the vehicle is connected to the charging device, determine the maximum voltage among the voltages of the batteries in the battery pack, and determine the difference between the voltage of each battery and the maximum voltage, so as to obtain the voltage difference corresponding to each battery.

[0096] The battery grouping module 804 is used to group the battery groups according to the voltage differences when determining that the battery groups are unbalanced according to the voltage differences to obtain at least one battery group, wherein the voltage difference between different batteries in the same battery group is less than or equal to a preset threshold.

[0097] The battery charging module 806 is used to determine the charging requirement parameters corresponding to each battery group, charge the battery group according to the charging requirement parameters corresponding to the battery group, and determine the minimum voltage among the voltages of each battery in the battery group during the charging process. When the difference between the minimum voltage and the maximum voltage is less than or equal to a preset threshold, the charging of the battery group is completed.

[0098] In some embodiments, the battery charging module 806 is also used to determine the maximum remaining capacity ratio from the remaining capacity ratios of each battery in the battery pack; determine the minimum remaining capacity ratio from the remaining capacity ratios of each battery in the battery group; determine the difference between the maximum remaining capacity ratio and the minimum remaining capacity ratio to obtain the remaining capacity ratio difference; determine the charging demand parameters corresponding to the battery group based on the remaining capacity ratio difference and the rated capacity.

[0099] In some embodiments, the battery grouping module 804 is also used to count the voltage difference values ​​that are greater than the voltage difference threshold among the voltage difference values ​​to obtain a target number; when the target number reaches a preset number threshold, it is determined that the batteries in the battery group are unbalanced, and the battery group is grouped according to the voltage difference values ​​to obtain at least one battery grouping.

[0100] In some embodiments, the charging device is a DC charging device, the batteries in the battery pack are combined in series, the positive electrode of the battery pack is connected to the positive electrode of the DC charging device through a first positive relay, the negative electrode of the battery pack is connected to the negative electrode of the DC charging device through a first negative relay, the positive electrode of the DC charging device is connected to the input positive electrode of the DC conversion device in the vehicle through a second positive relay, and the negative electrode of the DC charging device is connected to the input negative electrode of the DC conversion device through a second negative relay. For each battery in the battery pack, the positive electrode of the battery is connected to the output positive electrode of the DC conversion device through a corresponding first semiconductor switch, and the negative electrode of the battery is connected to the output negative electrode of the DC conversion device through a corresponding second semiconductor switch. Each battery group is charged in sequence. Before charging each battery group, the battery charging module 806 is also used to control the first positive relay to be disconnected and the second positive relay to be closed; the battery charging module 806 is also used to control the first semiconductor switch and the second semiconductor switch corresponding to each battery in the battery group to be closed, and control the first semiconductor switch and the second semiconductor switch corresponding to the remaining batteries in the battery pack to be disconnected; the charging requirement parameters corresponding to the battery group are sent to the DC charging device, so that the DC charging device charges the battery group according to the charging requirement parameters corresponding to the battery group.

[0101] In some embodiments, the battery charging module 806 is further configured to control the second positive relay to be disconnected and the first positive relay to be closed when the last battery group in the sequence stops charging, so as to charge the entire battery group using a DC charging device.

[0102] In some embodiments, the charging device is an AC charging device, the batteries in the battery pack are combined in series, the positive electrode of the AC charging device is connected to the input positive electrode of the on-board charging device in the vehicle through a third positive relay, the negative electrode of the AC charging device is connected to the input negative electrode of the on-board charging device through a third negative relay, the positive electrode of the battery pack is connected to the output positive electrode of the on-board charging device through a fourth positive relay, and the negative electrode of the battery pack is connected to the output negative electrode of the on-board charging device through a fourth negative relay. For each battery in the battery pack, the positive electrode of the battery is connected to the output positive electrode of the on-board charging device through a corresponding first semiconductor switch, and the negative electrode of the battery is connected to the output positive electrode of the on-board charging device through a corresponding second semiconductor switch. The switch is connected to the output negative pole of the on-board charging device, and each battery group is charged in sequence. Before charging each battery group, the battery charging module 806 is also used to control the fourth positive relay to open and the third positive relay to close; the battery charging module 806 is also used to control the first semiconductor switch and the second semiconductor switch corresponding to each battery in the battery group to close, and control the first semiconductor switch and the second semiconductor switch corresponding to the remaining batteries in the battery pack to open; the charging requirement parameters corresponding to the battery group are sent to the on-board charging device, so that the on-board charging device charges the battery group according to the charging requirement parameters corresponding to the battery group.

[0103] In some embodiments, the battery charging module 806 is further used to send a balanced charging instruction to the vehicle control device upon receiving a charging permission instruction sent by the vehicle control device and determining that the batteries in the battery pack are unbalanced, so that the vehicle control device controls the third positive relay to close.

[0104] Each module in the above-mentioned battery charging device can be implemented in whole or in part by software, hardware or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of the processor in the battery management device in the form of hardware, or can be stored in the memory in the battery management device in the form of software, so that the processor can call and execute the corresponding operations of each of the above modules.

[0105] In some embodiments, a battery management device is provided, which may be a server, and its internal structure diagram may be shown in FIG9. The battery management device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The system bus may be, but is not limited to, a CAN bus, an SPI bus or an I2C bus. The processor of the battery management device is used to provide computing and control capabilities. The memory of the battery management device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the battery management device is used to store data involved in the battery charging method. The input / output interface of the battery management device is used to exchange information between the processor and an external device. The communication interface of the battery management device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a battery charging method is implemented.

[0106] Those skilled in the art will understand that the structure shown in FIG. 9 is merely a block diagram of a partial structure related to the scheme of the present application, and does not constitute a limitation on the battery management device to which the scheme of the present application is applied. The specific battery management device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0107] In some embodiments, a battery management device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned battery charging method when executing the computer program.

[0108] In some embodiments, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned battery charging method are implemented.

[0109] In some embodiments, a computer program product is provided, comprising a computer program, which implements the steps in the above-mentioned battery charging method when executed by a processor.

[0110] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0111] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0112] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0113] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A battery charging method, characterized in that: The method comprises: When the vehicle is connected to the charging device, the voltage of each battery in the battery pack of the vehicle is obtained, the maximum voltage among the voltages of the batteries in the battery pack is determined, and the difference between the voltage of each battery and the maximum voltage is determined to obtain the voltage difference corresponding to each battery; In the case where the battery pack is determined to be unbalanced according to each of the voltage differences, the battery pack is grouped according to each of the voltage differences to obtain at least one battery group, wherein the difference between the voltages of different batteries in the same battery group is less than or equal to a preset threshold; For each of the battery groups, the maximum remaining capacity ratio is determined from the remaining capacity ratios of each battery in the battery pack, the minimum remaining capacity ratio is determined from the remaining capacity ratios of each battery in the battery group, the difference between the maximum remaining capacity ratio and the minimum remaining capacity ratio is determined, and the remaining capacity ratio difference is obtained, and the charging requirement parameters corresponding to the battery group are determined according to the remaining capacity ratio difference and the rated capacity, the battery group is charged according to the charging requirement parameters corresponding to the battery group, and the minimum voltage among the voltages of each battery in the battery group during the charging process is determined, and the charging of the battery group is completed when the difference between the minimum voltage and the maximum voltage is less than or equal to the preset threshold.

2. The method according to claim 1, characterized in that The batteries in the battery pack belong to the same battery type, and the remaining capacity ratio of each battery is determined according to an open circuit voltage-remaining capacity ratio curve corresponding to the battery type. The method further includes: Determine multiple preset remaining capacity ratios; For each of the preset remaining capacity ratios, a first voltage test method is used to determine the open circuit voltage of the test battery when the test battery of the battery type meets the preset remaining capacity ratio, and obtain a first open circuit voltage corresponding to the preset remaining capacity ratio; For each of the preset remaining capacity ratios, a second voltage test method is used to determine the open circuit voltage of the test battery when the test battery satisfies the preset remaining capacity ratio, and obtain a second open circuit voltage corresponding to the preset remaining capacity ratio; For each of the preset remaining capacity ratios, determining a target open circuit voltage corresponding to the preset remaining capacity ratio according to a first open circuit voltage and a second open circuit voltage corresponding to the preset remaining capacity ratio; Based on the target open circuit voltages corresponding to the preset remaining capacity percentages, an open circuit voltage-remaining capacity percentage curve corresponding to the battery type is generated.

3. The method according to claim 2, characterized in that The first open circuit voltage and the second open circuit voltage are obtained when the test battery is at a specified temperature, and the specified temperature is consistent with the current temperature of the battery pack. The method further includes: According to the multiple preset remaining capacity proportions, at least one first type of proportion range and at least one second type of proportion range are determined, each of the proportion ranges is represented by two different preset remaining capacity proportions, within the first type of proportion range, the change rate of the open circuit voltage of the test battery is greater than or equal to a preset change rate threshold, and within the second type of proportion range, the change rate of the open circuit voltage of the test battery is less than the change rate threshold; The determining, according to the first open circuit voltage and the second open circuit voltage corresponding to the preset remaining capacity ratio, a target open circuit voltage corresponding to the preset remaining capacity ratio, comprises: When the preset remaining capacity ratio belongs to the first type of ratio range, weighted averaging the first open circuit voltage and the second open circuit voltage corresponding to the preset remaining capacity ratio is performed to obtain a target open circuit voltage corresponding to the preset remaining capacity ratio; When the preset remaining capacity ratio belongs to the second type of ratio range, according to the specified temperature, a target open circuit voltage corresponding to the preset remaining capacity ratio is selected from the first open circuit voltage and the second open circuit voltage corresponding to the preset remaining capacity ratio.

4. The method according to claim 1, characterized in that: In the case where the battery unbalance of the battery group is determined according to each of the voltage differences, the battery group is grouped according to each of the voltage differences to obtain at least one battery group, including: Counting the number of voltage difference values ​​greater than the voltage difference threshold among the voltage difference values ​​to obtain a target number; When the target number reaches a preset number threshold, it is determined that the batteries of the battery group are unbalanced, and the battery group is grouped according to each of the voltage differences to obtain at least one battery group.

5. The method according to any one of claims 1 to 4, characterized in that: The charging device is a DC charging device, the batteries in the battery pack are combined in series, the positive electrode of the battery pack is connected to the positive electrode of the DC charging device through a first positive relay, the negative electrode of the battery pack is connected to the negative electrode of the DC charging device through a first negative relay, the positive electrode of the DC charging device is connected to the input positive electrode of the DC conversion device in the vehicle through a second positive relay, and the negative electrode of the DC charging device is connected to the input negative electrode of the DC conversion device through a second negative relay. For each battery in the battery pack, the positive electrode of the battery is connected to the output positive electrode of the DC conversion device through a corresponding first semiconductor switch, and the negative electrode of the battery is connected to the output negative electrode of the DC conversion device through a corresponding second semiconductor switch. Each of the battery groups is charged in sequence. Before charging each of the battery groups, the method further includes: Controlling the first positive relay to be opened, and controlling the second positive relay to be closed; The charging of the battery group according to the charging requirement parameters corresponding to the battery group includes: Controlling the first semiconductor switch and the second semiconductor switch corresponding to each battery in the battery group to be closed, and controlling the first semiconductor switches and the second semiconductor switches corresponding to the remaining batteries in the battery group to be opened; The charging requirement parameters corresponding to the battery group are sent to the DC charging device, so that the DC charging device charges the battery group according to the charging requirement parameters corresponding to the battery group.

6. The method according to claim 5, characterized in that The method further comprises: When the last battery group in sequence stops charging, the second positive relay is controlled to be opened, and the first positive relay is controlled to be closed, so as to charge the entire battery group using the DC charging device.

7. The method according to any one of claims 1 to 4, characterized in that: The charging device is an AC charging device, the batteries in the battery pack are combined in series, the positive electrode of the AC charging device is connected to the input positive electrode of the on-board charging device in the vehicle through a third positive relay, the negative electrode of the AC charging device is connected to the input negative electrode of the on-board charging device through a third negative relay, the positive electrode of the battery pack is connected to the output positive electrode of the on-board charging device through a fourth positive relay, and the negative electrode of the battery pack is connected to the output negative electrode of the on-board charging device through a fourth negative relay. For each battery in the battery pack, the positive electrode of the battery is connected to the output positive electrode of the on-board charging device through a corresponding first semiconductor switch, and the negative electrode of the battery is connected to the output negative electrode of the on-board charging device through a corresponding second semiconductor switch. Each of the battery groups is charged in sequence. Before charging each of the battery groups, the method further includes: Controlling the fourth positive relay to be disconnected, and controlling the third positive relay to be closed; The charging of the battery group according to the charging requirement parameters corresponding to the battery group includes: Controlling the first semiconductor switch and the second semiconductor switch corresponding to each battery in the battery group to be closed, and controlling the first semiconductor switches and the second semiconductor switches corresponding to the remaining batteries in the battery group to be opened; The charging requirement parameters corresponding to the battery group are sent to the on-board charging device, so that the on-board charging device charges the battery group according to the charging requirement parameters corresponding to the battery group.

8. The method according to claim 7, characterized in that The controlling the third positive relay to close comprises: When receiving a charge permission instruction sent by a vehicle control device and determining that the batteries of the battery pack are unbalanced, a balanced charge instruction is sent to the vehicle control device so that the vehicle control device controls the third positive relay to close.

9. A battery charging device, characterized in that: The device comprises: A voltage difference determination module is used to obtain the voltage of each battery in the battery pack of the vehicle when the vehicle is connected to the charging device, determine the maximum voltage among the voltages of the batteries in the battery pack, and determine the difference between the voltage of each battery and the maximum voltage, so as to obtain the voltage difference corresponding to each battery; A battery grouping module, configured to group the battery group according to the voltage differences to obtain at least one battery group when the battery imbalance of the battery group is determined according to the voltage differences to obtain at least one battery group, wherein the voltage difference between different batteries in the same battery group is less than or equal to a preset threshold; A battery charging module is used to determine, for each battery group, a maximum remaining capacity ratio from the remaining capacity ratios of each battery in the battery pack, determine a minimum remaining capacity ratio from the remaining capacity ratios of each battery in the battery group, determine a difference between the maximum remaining capacity ratio and the minimum remaining capacity ratio, obtain a remaining capacity ratio difference, determine a charging requirement parameter corresponding to the battery group according to the remaining capacity ratio difference and a rated capacity, charge the battery group according to the charging requirement parameter corresponding to the battery group, and determine a minimum voltage among the voltages of each battery in the battery group during the charging process, and complete the charging of the battery group when the difference between the minimum voltage and the maximum voltage is less than or equal to the preset threshold.

10. The device according to claim 9, characterized in that The charging device is a DC charging device, and the batteries in the battery pack are combined in series. The positive electrode of the battery pack is connected to the positive electrode of the DC charging device through a first positive relay, and the negative electrode of the battery pack is connected to the negative electrode of the DC charging device through a first negative relay. The positive electrode of the DC charging device is connected to the input positive electrode of the DC conversion device in the vehicle through a second positive relay, and the negative electrode of the DC charging device is connected to the input negative electrode of the DC conversion device through a second negative relay. For each battery in the battery pack, the positive electrode of the battery is connected to the output positive electrode of the DC conversion device through a corresponding first semiconductor switch, and the negative electrode of the battery is connected to the output negative electrode of the DC conversion device through a corresponding second semiconductor switch.

11. The device according to claim 9, characterized in that The charging device is an AC charging device, and the batteries in the battery pack are combined in series. The positive electrode of the AC charging device is connected to the input positive electrode of the on-board charging device in the vehicle through a third positive relay, and the negative electrode of the AC charging device is connected to the input negative electrode of the on-board charging device through a third negative relay. The positive electrode of the battery pack is connected to the output positive electrode of the on-board charging device through a fourth positive relay, and the negative electrode of the battery pack is connected to the output negative electrode of the on-board charging device through a fourth negative relay. For each battery in the battery pack, the positive electrode of the battery is connected to the output positive electrode of the on-board charging device through a corresponding first semiconductor switch, and the negative electrode of the battery is connected to the output negative electrode of the on-board charging device through a corresponding second semiconductor switch.

12. A battery management device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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