A battery charging method, device, medium and BMS system

Abstract

The present application relates to the technical field of battery, especially a battery charging method, device, medium and BMS system. The present application adopts SOC to judge the charging stage when the highest single voltage is less than or equal to the platform period, and adopts the highest single voltage to judge the charging stage when the highest single voltage is greater than the platform period, which can avoid the problem that the charging stage rises too fast in the low temperature charging stage in the traditional judgment strategy, and improve the judgment accuracy of the charging stage. At the same time, the current charging stage is judged in real time, and the charging stage can be raised or lowered with the changes of SOC, the highest single voltage and temperature, which improves the charging experience of the user.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a battery charging method, apparatus, medium, and BMS system. Background Technology

[0002] As the penetration rate of electric vehicles continues to increase, end consumers are demanding more from their vehicle usage experience. As an important parameter closely related to user perception, charging time has an undeniable impact on the user experience.

[0003] For battery charging, especially lithium iron phosphate batteries, there is a plateau period in the change of the highest single-cell voltage during the charging process. During this plateau period, the highest single-cell voltage remains almost unchanged, making it impossible to determine the transition of charging stages based on this. Furthermore, because the highest single-cell voltage of the battery rises rapidly when charging at low temperatures, the charging stages increase rapidly. However, when the charging current decreases due to the increase in charging stages, the charging stages in the traditional charging calculation strategy cannot be reduced again, causing the charging current to remain at a small value. This results in the actual charging process taking a very long time.

[0004] Traditional charging control strategies rely on the State of Charge (SOC) value to determine the charging stage. However, when the calculated SOC value deviates significantly, there may be errors in determining the charging stage, potentially leading to overcharging risks. During low-temperature charging, the internal resistance of individual battery cells is high, and a large charging current can cause a significant increase in the highest voltage of a single battery cell. This results in the charging stage rapidly advancing to a higher level, leading to charging with a smaller current and a longer remaining charging time. Summary of the Invention

[0005] This invention discloses a battery charging method, apparatus, medium, and BMS system, which can select the SOC or the highest single cell voltage of the battery to determine the current charging stage in real time at an appropriate stage, thereby optimizing the charging strategy.

[0006] To achieve the above objectives, a battery charging method is provided, the specific method of which is as follows:

[0007] Determine the highest single-cell voltage of the battery to be charged during the charging plateau period and set it as the first threshold voltage.

[0008] When the battery to be charged is in a charging state, if the highest single cell voltage of the battery to be charged is within the first threshold voltage, the charging stage is determined in real time based on the current SOC of the battery to be charged, and the charging strategy is determined in real time based on the charging stage.

[0009] When the battery to be charged is in a charging state, if the current highest single cell voltage of the battery to be charged is greater than the first threshold voltage, the charging stage is determined in real time based on the current highest single cell voltage of the battery to be charged, and the charging strategy is determined in real time based on the charging stage.

[0010] The advantage of this embodiment is that it uses SOC to determine the charging stage when the highest single-cell voltage is lower than the plateau period, and uses the highest single-cell voltage to determine the charging stage when the highest single-cell voltage is higher than the plateau period. This avoids the problem of the charging stage rising too quickly due to the low temperature charging stage in the traditional judgment strategy, and improves the accuracy of the charging stage judgment. At the same time, it uses a real-time judgment method to determine the current charging stage. As SOC, highest single-cell voltage and temperature change, the charging stage can rise or fall, which improves the user's charging experience.

[0011] Furthermore, when the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, or when the highest single-cell voltage of the battery to be charged changes from above the first threshold voltage to within the first threshold voltage, the judgment method for the current charging stage must be changed only after the preset conditions are met.

[0012] The advantage of this embodiment is that it adopts a hysteresis control strategy during the charging phase, which can effectively prevent frequent increases and decreases during the charging phase and avoid damage to the battery caused by frequent switching of charging modes.

[0013] Optionally, the preset condition is a first time threshold and a second time threshold;

[0014] When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, it is determined whether the time the battery to be charged maintains the first threshold voltage is greater than the first time threshold. If it is greater than the first time threshold, it is allowed to switch from judging the charging stage in real time from the current SOC to judging the charging stage in real time from the highest single-cell voltage.

[0015] When the highest single-cell voltage of the battery to be charged changes from being greater than the first threshold voltage to being within the first threshold voltage, it is determined whether the time during which the battery to be charged maintains a voltage greater than the first threshold voltage is greater than a second time threshold. If it is greater than the second time threshold, it is allowed to switch from judging the charging stage in real time based on the current highest single-cell voltage to judging the charging stage in real time based on the current SOC.

[0016] Optionally, the preset conditions are a second threshold voltage and a third threshold voltage, wherein the second threshold voltage is greater than the first threshold voltage and the third threshold voltage;

[0017] When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, it is determined whether the highest single-cell voltage of the battery to be charged is greater than the second threshold voltage. If it is greater than the second threshold voltage, it is allowed to switch from judging the charging stage in real time from the current SOC to judging the charging stage in real time from the highest single-cell voltage.

[0018] When the highest single-cell voltage of the battery to be charged changes from greater than the first threshold voltage to within the first threshold voltage, it is determined whether the highest single-cell voltage of the battery to be charged is less than the third threshold voltage. If it is less than the third threshold voltage, the charging stage can be determined in real time by the current highest single-cell voltage, or by the current SOC.

[0019] Preferably, the preset conditions are a second threshold voltage and a third time threshold, wherein the second threshold voltage is greater than the first threshold voltage;

[0020] When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, it is determined whether the highest single-cell voltage of the battery to be charged is greater than the second threshold voltage. If it is greater than the second threshold voltage, it is allowed to switch from judging the charging stage in real time from the current SOC to judging the charging stage in real time from the highest single-cell voltage.

[0021] When the highest single-cell voltage of the battery to be charged changes from above the first threshold voltage to below the first threshold voltage, it is determined whether the time it takes for the battery to enter the first threshold voltage range is greater than a third time threshold. If it is greater than the third time threshold, the charging stage can be determined in real time by the current highest single-cell voltage instead of by the current SOC.

[0022] As a preferred method, the specific method for determining the highest single-cell voltage of the battery to be charged during the charging plateau period is as follows:

[0023] Select the same type of battery as the battery to be charged as the test battery, place the test battery at different temperatures to start charging, and record the curve of the highest single cell voltage of the test battery changing with time during each charging.

[0024] Expert analysis determined the highest single-cell voltage of the battery under different temperatures during its plateau period.

[0025] The highest single-cell voltage during the current plateau period is determined based on the actual charging temperature of the battery to be charged.

[0026] This embodiment introduces temperature as a determining factor for judging the highest single-cell voltage during the plateau period, which can improve the accuracy of the calculation of the highest single-cell voltage during the plateau period, thereby improving charging efficiency and quality.

[0027] Optionally, the specific method for determining the highest single-cell voltage of the battery under charge during the charging plateau period is as follows:

[0028] Based on the model of the battery to be charged and the current charging temperature, the map table is queried to obtain the information.

[0029] Optionally, the specific method for determining the highest single-cell voltage of the battery under charge during the charging plateau period is as follows:

[0030] After determining the model of the battery to be charged and the current charging temperature, the data is obtained through a predictive model.

[0031] Preferably, the charging stage is determined in real time based on the current SOC or the current highest single-cell voltage of the battery to be charged. The specific method is as follows:

[0032] The current SOC value or highest single-cell voltage of the battery to be charged is used, along with the current charging temperature and the battery model, to query the map table and obtain the current charging stage.

[0033] The advantage of this embodiment is that it introduces a temperature factor, and the criteria for judging the charging stage vary at different temperatures, which is more in line with real-world usage scenarios and improves the stability and accuracy of the charging stage judgment.

[0034] Optionally, the charging stage can be determined in real time based on the current SOC or the current highest single-cell voltage of the battery to be charged. The specific method is as follows:

[0035] Select a judgment model based on the current charging temperature and the model of the battery to be charged, and input the current SOC value or the current highest single cell voltage of the battery to be charged into the judgment model to obtain the current charging stage;

[0036] The judgment model is a random forest model.

[0037] Optionally, the charging strategy is constant current charging, which maintains a constant charging current with different charging voltages at different stages.

[0038] Optionally, the charging strategy is constant voltage charging, in which the same charging voltage is used at different stages, and the charging current continuously decreases.

[0039] Optionally, the charging strategy is to set a constant charging current for different charging stages, and continuously increase the charging voltage in each stage to keep the charging current constant.

[0040] Preferably, in each charging stage, the charging voltage is less than a preset upper voltage limit; if the current charging voltage cannot maintain a constant charging current, then the charging is performed at the preset upper voltage limit.

[0041] To achieve the above objectives, another aspect is to provide a battery charging device, including: a plateau voltage calculation module, a charging stage judgment module, and a charging strategy judgment module;

[0042] The plateau voltage calculation module determines the highest single-cell voltage of the battery to be charged during the charging plateau period and sets it as the first threshold voltage.

[0043] The charging stage determination module determines the charging stage in real time based on the current SOC of the battery when the battery is in a charging state, if the current highest single-cell voltage of the battery is within the first threshold voltage; and if the current highest single-cell voltage of the battery is greater than the first threshold voltage when the battery is in a charging state.

[0044] The charging strategy determination module determines the charging strategy in real time based on the charging stage.

[0045] Furthermore, the charging method is either DC charging or AC charging.

[0046] Furthermore, when the current highest single-cell voltage of the battery to be charged is greater than the first threshold voltage, it is determined whether the current highest single-cell voltage is greater than the minimum threshold for single-cell voltage that is not allowed to be reduced.

[0047] If the voltage exceeds the minimum threshold of the single cell voltage, the currently determined charging stage can only be increased, not decreased, until it is fully charged;

[0048] If the voltage is less than the minimum threshold of the single-cell voltage, the currently determined charging stage can be increased or decreased.

[0049] To achieve the above objectives, another aspect is to provide a storage medium storing a plurality of instructions that are applicable to a processor for loading to execute the battery charging method described above.

[0050] To achieve the above objectives, another aspect is to provide a BMS system, including the aforementioned battery charging device and / or the aforementioned storage medium.

[0051] It should be noted that the terms "first," "second," and similar terms used in this article are merely for describing the constituent elements of the technical solution and do not constitute a limitation on the technical solution, nor should they be interpreted as an indication or implication of the importance of the corresponding elements; elements with terms such as "first," "second," or similar terms indicate that at least one of the elements is included in the corresponding technical solution. Attached Figure Description

[0052] To more clearly illustrate the technical solution of the present invention and facilitate a further understanding of its technical effects, features, and objectives, the present invention will be described in detail below with reference to the accompanying drawings. The drawings constitute an essential part of the specification and are used together with Embodiment 1 of the present invention to illustrate the technical solution of the present invention, but do not constitute a limitation on the present invention.

[0053] The same reference numerals in the attached diagrams represent the same parts, specifically:

[0054] Figure 1 This is a schematic diagram of the charging process of the present invention. Detailed Implementation

[0055] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Of course, the specific embodiments described below are merely illustrative of the technical solutions of the present invention, and not intended to limit the invention. Furthermore, the parts described in the embodiments or drawings are merely illustrative examples of relevant parts of the present invention, and not the entirety of the invention.

[0056] Example 1:

[0057] A battery charging method, such as Figure 1 As shown, the specific steps are as follows:

[0058] S1. Determine the highest single-cell voltage of the battery to be charged during the charging plateau period and set it as the first threshold voltage.

[0059] Specifically, the method for determining the highest single-cell voltage of the battery during the charging plateau period is as follows:

[0060] Based on the model of the battery to be charged and the current charging temperature, the map table is queried to obtain the information.

[0061] S2. When the battery to be charged is in a charging state, determine whether the current highest single cell voltage of the battery to be charged is less than or equal to the first threshold voltage or greater than the first threshold voltage.

[0062] S3. If the highest single-cell voltage of the battery to be charged is within the first threshold voltage, the charging stage is determined in real time based on the current SOC of the battery to be charged, and the charging strategy is determined in real time based on the charging stage.

[0063] If the highest single-cell voltage of the battery to be charged is greater than the first threshold voltage, the charging stage is determined in real time based on the highest single-cell voltage of the battery to be charged, and the charging strategy is determined in real time based on the charging stage.

[0064] Specifically, the charging stage is determined in real time based on the current SOC or the current highest single-cell voltage of the battery to be charged. The specific method is as follows:

[0065] Select a judgment model based on the current charging temperature and the model of the battery to be charged, and input the current SOC value or the current highest single cell voltage of the battery to be charged into the judgment model to obtain the current charging stage;

[0066] The judgment model is a random forest model.

[0067] S4. When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, or when the highest single-cell voltage of the battery to be charged changes from above the first threshold voltage to within the first threshold voltage, the judgment method of the current charging stage must be changed after the preset conditions are met.

[0068] Specifically, the preset conditions are a first time threshold and a second time threshold;

[0069] When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, it is determined whether the time the battery to be charged maintains the first threshold voltage is greater than the first time threshold. If it is greater than the first time threshold, it is allowed to switch from judging the charging stage in real time from the current SOC to judging the charging stage in real time from the highest single-cell voltage.

[0070] When the highest single-cell voltage of the battery to be charged changes from being greater than the first threshold voltage to being within the first threshold voltage, it is determined whether the time during which the battery to be charged maintains a voltage greater than the first threshold voltage is greater than a second time threshold. If it is greater than the second time threshold, it is allowed to switch from judging the charging stage in real time based on the current highest single-cell voltage to judging the charging stage in real time based on the current SOC.

[0071] S5. Charge the battery to be charged according to the charging strategy.

[0072] Specifically, the charging strategy is constant current charging, which maintains a constant charging current with different charging voltages at different stages.

[0073] Specifically, the charging method is AC charging.

[0074] Example 2:

[0075] A battery charging method, such as Figure 1 As shown, the specific steps are as follows:

[0076] S1. Determine the highest single-cell voltage of the battery to be charged during the charging plateau period and set it as the first threshold voltage.

[0077] Specifically, the method for determining the highest single-cell voltage of the battery during the charging plateau period is as follows:

[0078] After determining the model of the battery to be charged and the current charging temperature, the data is obtained through a predictive model.

[0079] S2. When the battery to be charged is in a charging state, determine whether the current highest single cell voltage of the battery to be charged is less than or equal to the first threshold voltage or greater than the first threshold voltage.

[0080] S3. If the highest single-cell voltage of the battery to be charged is within the first threshold voltage, the charging stage is determined in real time based on the current SOC of the battery to be charged, and the charging strategy is determined in real time based on the charging stage.

[0081] If the highest single-cell voltage of the battery to be charged is greater than the first threshold voltage, the charging stage is determined in real time based on the highest single-cell voltage of the battery to be charged, and the charging strategy is determined in real time based on the charging stage.

[0082] Specifically, the charging stage is determined in real time based on the current SOC or the current highest single-cell voltage of the battery to be charged. The specific method is as follows:

[0083] Select a judgment model based on the current charging temperature and the model of the battery to be charged, and input the current SOC value or the current highest single cell voltage of the battery to be charged into the judgment model to obtain the current charging stage;

[0084] The judgment model is a random forest model.

[0085] S4. When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, or when the highest single-cell voltage of the battery to be charged changes from above the first threshold voltage to within the first threshold voltage, the judgment method of the current charging stage must be changed after the preset conditions are met.

[0086] Specifically, the preset conditions are a second threshold voltage and a third threshold voltage, wherein the second threshold voltage is greater than the first threshold voltage and the third threshold voltage;

[0087] When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, it is determined whether the highest single-cell voltage of the battery to be charged is greater than the second threshold voltage. If it is greater than the second threshold voltage, it is allowed to switch from judging the charging stage in real time from the current SOC to judging the charging stage in real time from the highest single-cell voltage.

[0088] When the highest single-cell voltage of the battery to be charged changes from greater than the first threshold voltage to within the first threshold voltage, it is determined whether the highest single-cell voltage of the battery to be charged is less than the third threshold voltage. If it is less than the third threshold voltage, the charging stage can be determined in real time by the current highest single-cell voltage, or by the current SOC.

[0089] S5. Charge the battery to be charged according to the charging strategy.

[0090] Specifically, the charging strategy is constant voltage charging, which uses the same charging voltage at different stages, while the charging current continuously decreases.

[0091] Specifically, the charging method is DC charging.

[0092] Example 3:

[0093] A battery charging method, such as Figure 1 As shown, the specific steps are as follows:

[0094] S1. Determine the highest single-cell voltage of the battery to be charged during the charging plateau period and set it as the first threshold voltage.

[0095] Specifically, the method for determining the highest single-cell voltage of the battery during the charging plateau period is as follows:

[0096] Select the same type of battery as the battery to be charged as the test battery, place the test battery at different temperatures to start charging, and record the curve of the highest single cell voltage of the test battery changing with time during each charging.

[0097] Expert analysis determined the highest single-cell voltage of the battery under different temperatures during its plateau period.

[0098] The highest single-cell voltage during the current plateau period is determined based on the actual charging temperature of the battery to be charged.

[0099] S2. When the battery to be charged is in a charging state, determine whether the current highest single cell voltage of the battery to be charged is less than or equal to the first threshold voltage or greater than the first threshold voltage.

[0100] S3. If the highest single-cell voltage of the battery to be charged is within the first threshold voltage, the charging stage is determined in real time based on the current SOC of the battery to be charged, and the charging strategy is determined in real time based on the charging stage.

[0101] If the highest single-cell voltage of the battery to be charged is greater than the first threshold voltage, the charging stage is determined in real time based on the highest single-cell voltage of the battery to be charged, and the charging strategy is determined in real time based on the charging stage.

[0102] Specifically, the charging stage is determined in real time based on the current SOC or the current highest single-cell voltage of the battery to be charged. The specific method is as follows:

[0103] The current SOC value or highest single-cell voltage of the battery to be charged is used, along with the current charging temperature and the battery model, to query the map table and obtain the current charging stage.

[0104] Furthermore, when the current highest single-cell voltage of the battery to be charged is greater than the first threshold voltage, it is determined whether the current highest single-cell voltage is greater than the minimum threshold for single-cell voltage that is not allowed to be reduced.

[0105] If the voltage exceeds the minimum threshold of the single cell voltage, the currently determined charging stage can only be increased, not decreased, until it is fully charged.

[0106] If the voltage is less than the minimum threshold of the single-cell voltage, the currently determined charging stage can be increased or decreased.

[0107] S4. When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, or when the highest single-cell voltage of the battery to be charged changes from above the first threshold voltage to within the first threshold voltage, the judgment method of the current charging stage must be changed after the preset conditions are met.

[0108] Specifically, the preset conditions are a second threshold voltage and a third time threshold, wherein the second threshold voltage is greater than the first threshold voltage;

[0109] When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, it is determined whether the highest single-cell voltage of the battery to be charged is greater than the second threshold voltage. If it is greater than the second threshold voltage, it is allowed to switch from judging the charging stage in real time from the current SOC to judging the charging stage in real time from the highest single-cell voltage.

[0110] When the highest single-cell voltage of the battery to be charged changes from above the first threshold voltage to below the first threshold voltage, it is determined whether the time it takes for the battery to enter the first threshold voltage range is greater than a third time threshold. If it is greater than the third time threshold, the charging stage can be determined in real time by the current highest single-cell voltage instead of by the current SOC.

[0111] S5. Charge the battery to be charged according to the charging strategy.

[0112] Specifically, the charging strategy is to set a constant charging current for different charging stages, and to continuously increase the charging voltage in each stage to keep the charging current constant.

[0113] Specifically, the charging method is AC charging.

[0114] As can be seen from step S1 of Examples 1, 2 and 3, the highest single-cell voltage during the plateau period can be measured by testing the same type of test battery at the same temperature, or it can be obtained by looking up a table or data interaction. Alternatively, it can be calculated by selecting the corresponding AI prediction model based on the battery model and charging temperature. Of course, other methods can also be used to obtain the voltage.

[0115] As can be seen from step S3 of Embodiments 1, 2 and 3, the way to determine the charging stage in real time based on the current SOC or the current highest single-cell voltage of the battery to be charged can be to input the current highest single-cell voltage or SOC value into a table for query, or to input the current highest single-cell voltage or SOC value into a classification model, or of course, other methods.

[0116] As can be seen from step S4 of Embodiments 1, 2 and 3, when the voltage fluctuates up and down during the plateau period, preset conditions can be set to avoid frequent switching of the charging strategy. The preset conditions can be time conditions, voltage magnitude conditions, time conditions combined with voltage magnitude conditions, or other comprehensive conditions.

[0117] As can be seen from step S5 of Embodiments 1, 2 and 3, the charging strategy can be constant current, constant voltage, or a combination of phased constant current and constant voltage, and of course, other charging strategies are also possible.

[0118] Example 4:

[0119] A battery charging device includes: a plateau voltage calculation module, a charging stage judgment module, and a charging strategy judgment module;

[0120] The plateau voltage calculation module determines the highest single-cell voltage of the battery to be charged during the charging plateau period and sets it as the first threshold voltage.

[0121] The charging stage determination module determines the charging stage in real time based on the current SOC of the battery when the battery is in a charging state, if the current highest single-cell voltage of the battery is within the first threshold voltage; and if the current highest single-cell voltage of the battery is greater than the first threshold voltage when the battery is in a charging state.

[0122] The charging strategy determination module determines the charging strategy in real time based on the charging stage.

[0123] In this embodiment, the plateau voltage calculation module can be a remote server or a local storage device in the vehicle; the charging stage judgment module and the charging strategy judgment module can be a local controller with calculation function in the vehicle, or a remote server or terminal.

[0124] It should be noted that the above embodiments are only for more clearly illustrating the technical solution of the present invention. Those skilled in the art will understand that the implementation of the present invention is not limited to the above content. Any obvious changes, substitutions or replacements made based on the above content do not exceed the scope of the technical solution of the present invention. Other implementations will also fall within the scope of the present invention without departing from the concept of the present invention.

Claims

1. A battery charging method, characterized in that, The specific method is as follows: Determine the highest single-cell voltage of the battery to be charged during the charging plateau period and set it as the first threshold voltage. When the battery to be charged is in a charging state, if the highest single cell voltage of the battery to be charged is within the first threshold voltage, the charging stage is determined in real time based on the current SOC of the battery to be charged, and the charging strategy is determined in real time based on the charging stage. When the battery to be charged is in a charging state, if the current highest single cell voltage of the battery to be charged is greater than the first threshold voltage, the charging stage is determined in real time based on the current highest single cell voltage of the battery to be charged, and the charging strategy is determined in real time based on the charging stage.

2. The battery charging method as described in claim 1, characterized in that, When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, or when the highest single-cell voltage of the battery to be charged changes from above the first threshold voltage to within the first threshold voltage, the judgment method for the current charging stage must be changed only after the preset conditions are met.

3. The battery charging method as described in claim 2, characterized in that, The preset conditions are a first time threshold and a second time threshold; When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, it is determined whether the time the battery to be charged maintains the first threshold voltage is greater than the first time threshold. If it is greater than the first time threshold, it is allowed to switch from judging the charging stage in real time from the current SOC to judging the charging stage in real time from the highest single-cell voltage. When the highest single-cell voltage of the battery to be charged changes from being greater than the first threshold voltage to being within the first threshold voltage, it is determined whether the time during which the battery to be charged maintains a voltage greater than the first threshold voltage is greater than a second time threshold. If it is greater than the second time threshold, it is allowed to switch from judging the charging stage in real time based on the current highest single-cell voltage to judging the charging stage in real time based on the current SOC.

4. The battery charging method as described in claim 2, characterized in that, The preset conditions are a second threshold voltage and a third threshold voltage, wherein the second threshold voltage is greater than the first threshold voltage and the third threshold voltage; When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, it is determined whether the highest single-cell voltage of the battery to be charged is greater than the second threshold voltage. If it is greater than the second threshold voltage, it is allowed to switch from judging the charging stage in real time from the current SOC to judging the charging stage in real time from the highest single-cell voltage. When the highest single-cell voltage of the battery to be charged changes from greater than the first threshold voltage to within the first threshold voltage, it is determined whether the highest single-cell voltage of the battery to be charged is less than the third threshold voltage. If it is less than the third threshold voltage, the charging stage can be determined in real time by the current highest single-cell voltage, or by the current SOC.

5. The battery charging method as described in claim 2, characterized in that, The preset conditions are a second threshold voltage and a third time threshold, wherein the second threshold voltage is greater than the first threshold voltage; When the highest single-cell voltage of the battery to be charged changes from within the first threshold voltage to above the first threshold voltage, it is determined whether the highest single-cell voltage of the battery to be charged is greater than the second threshold voltage. If it is greater than the second threshold voltage, it is allowed to switch from judging the charging stage in real time from the current SOC to judging the charging stage in real time from the highest single-cell voltage. When the highest single-cell voltage of the battery to be charged changes from above the first threshold voltage to below the first threshold voltage, it is determined whether the time it takes for the battery to enter the first threshold voltage range is greater than a third time threshold. If it is greater than the third time threshold, the charging stage can be determined in real time by the current highest single-cell voltage instead of by the current SOC.

6. The battery charging method as described in claim 1, characterized in that, The specific method for determining the highest single-cell voltage of the battery during the charging plateau period is as follows: Select the same type of battery as the battery to be charged as the test battery, place the test battery at different temperatures to start charging, and record the curve of the highest single cell voltage of the test battery changing with time during each charging. Expert analysis determined the highest single-cell voltage of the battery under different temperatures during its plateau period. The highest single-cell voltage during the current plateau period is determined based on the actual charging temperature of the battery to be charged.

7. The battery charging method as described in claim 1, characterized in that, The specific method for determining the highest single-cell voltage of the battery during the charging plateau period is as follows: Based on the model of the battery to be charged and the current charging temperature, the map table is queried to obtain the information.

8. The battery charging method as described in claim 1, characterized in that, The specific method for determining the highest single-cell voltage of the battery during the charging plateau period is as follows: After determining the model of the battery to be charged and the current charging temperature, the data is obtained through a predictive model.

9. The battery charging method as described in claim 1, characterized in that, The charging stage is determined in real time based on the current SOC or the current highest single-cell voltage of the battery to be charged. The specific method is as follows: The current SOC value or highest single-cell voltage of the battery to be charged is used, along with the current charging temperature and the battery model, to query the map table and obtain the current charging stage.

10. The battery charging method as described in claim 1, characterized in that, The charging stage is determined in real time based on the current SOC or the current highest single-cell voltage of the battery to be charged. The specific method is as follows: Select a judgment model based on the current charging temperature and the model of the battery to be charged, and input the current SOC value or the current highest single cell voltage of the battery to be charged into the judgment model to obtain the current charging stage; The judgment model is a random forest model.

11. The battery charging method as described in claim 1, characterized in that, The charging strategy is constant current charging, which maintains a constant charging current with different charging voltages at different stages.

12. The battery charging method as described in claim 1, characterized in that, The charging strategy is constant voltage charging, which uses the same charging voltage at different stages, while the charging current continuously decreases.

13. The battery charging method as described in claim 1, characterized in that, The charging strategy involves setting a constant charging current for different charging stages and continuously increasing the charging voltage within each stage to maintain a constant charging current.

14. The battery charging method as described in claim 13, characterized in that, In each charging stage, the charging voltage is less than the preset upper voltage limit; if the current charging voltage cannot maintain a constant charging current, the charging is performed at the preset upper voltage limit.

15. The battery charging method as described in claim 1, characterized in that, The charging method is either DC charging or AC charging.

16. The battery charging method as described in claim 1, characterized in that, When the highest single-cell voltage of the battery to be charged is greater than the first threshold voltage, it is determined whether the highest single-cell voltage is greater than the minimum threshold voltage of the single-cell voltage that is not allowed to be reduced. If the voltage exceeds the minimum threshold of the single cell voltage, the currently determined charging stage can only be increased, not decreased, until it is fully charged; If the voltage is less than the minimum threshold of the single-cell voltage, the currently determined charging stage can be increased or decreased.

17. A battery charging device, characterized in that, include: Platform voltage calculation module, charging stage judgment module, and charging strategy judgment module; The plateau voltage calculation module determines the highest single-cell voltage of the battery to be charged during the charging plateau period and sets it as the first threshold voltage. The charging stage determination module determines the charging stage in real time based on the current SOC of the battery when the battery is in a charging state, if the current highest single-cell voltage of the battery is within the first threshold voltage; and if the current highest single-cell voltage of the battery is greater than the first threshold voltage when the battery is in a charging state. The charging strategy determination module determines the charging strategy in real time based on the charging stage.

18. A storage medium, characterized in that, The storage medium stores a plurality of instructions which are adapted for loading by a processor to execute the battery charging method according to any one of claims 1 to 16.

19. A BMS system, characterized in that, Includes the battery charging device of claim 17 and / or the storage medium of claim 18.

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