SOC correction method for battery

Abstract

The invention provides an SOC correction method for a battery, and the method comprises the steps: entering an SOC correction process when a target battery is in a charging state and meets a correction starting condition; according to the current characteristic data of the target battery, a current calibration value is obtained from a first experiment data table, and a request current is sent to a charger according to the current calibration value; when a current difference value between a response current received by the target battery and the request current is within a threshold range, obtaining an SOC calibration value of the target battery from a second experimental data table according to current characteristic data of the target battery, and updating an SOC correction value; when the target battery meets the correction exit condition, the SOC value of the target battery is corrected through the SOC correction value, the estimated value of the SOC is adjusted under the condition of charging and not full charging, then more accurate battery management experience is provided for a user, and under the conditions of long-time use and plug-in and plug-out at any time, the user experience is improved. And the intelligent level of the charging system is improved.

Description

Technical Field

[0001] The present invention relates to the field of new energy, and in particular to a method for correcting the SOC of a battery. Background Art

[0002] In the actual long-term use of battery packs and chargers, existing technologies mostly rely on the MAP table of the battery manufacturer to control charging. These MAP tables are based on experimental data, and the power curve and charging strategy provided by the battery manufacturer jointly determine the charging process. This charging method has a certain degree of standardization and versatility, can adapt to different types of battery packs, and meet the basic charging requirements in most usage scenarios.

[0003] For example, charging is performed according to the national standard charging MAP table. The charging process usually follows a pre-set standard curve, and the performance of various types of batteries at different charging stages is verified through experiments to determine the appropriate charging power and current. These data are provided by battery manufacturers to ensure charging safety and efficiency in common usage scenarios. For another example, charging is performed according to the power curve of the battery manufacturer, and the charging system adjusts the charging power at different stages. This method can ensure that the battery maintains a reasonable power input in most charging stages, reduce the risk of overcharging or undercharging, and at the same time, ensure the service life of the battery.

[0004] Existing charging system designs usually assume that users can plug and unplug at will, that is, users do not need to care about the details of the charging process, and the charger will automatically adjust the charging parameters to ensure charging safety. However, the habit of plugging and unplugging may cause the battery to fail to be fully charged in some cases, or the charging efficiency may be affected due to improper current control.

[0005] The state of charge (SOC) of a battery is the ratio of the available power in the battery to the rated capacity, reflecting the remaining power of the battery. In current technology, the accumulated error caused by inaccurate remaining power during the long-term use of the battery pack cannot be effectively corrected.

[0006] As the SOC error gradually accumulates, the actual battery power will not match the estimated SOC value, which will affect the charging management system's accurate prediction of the remaining power, and thus affect the user experience. For example, the battery shows that the power is sufficient, but it is suddenly exhausted during use, or the battery shows that the power is insufficient but it can still continue to work. This accumulation of SOC errors is particularly obvious when the battery is not fully charged for a long time, resulting in the charging system being unable to provide accurate power estimates at critical time points, which may cause problems such as unreasonable charging and inaccurate battery life prediction, affecting the performance of the device and user experience.

[0007] Most existing technologies rely on correcting the SOC after the voltage reaches the fully charged state. However, in real-world usage scenarios, users often do not frequently charge the battery to full charge, especially when the battery is plugged in and unplugged at any time, and the battery may be partially charged for a long time.

[0008] How to provide a battery SOC correction method that can perform SOC calibration without relying on full battery charge, correct the battery SOC value while charging, and reduce SOC errors is of great significance to improving the user's battery management experience. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a battery SOC correction method, which adjusts the estimated SOC value when charging and not fully charged, thereby providing users with a more accurate battery management experience, and improving the intelligence level of the charging system when used for a long time and plugged in and unplugged at any time.

[0010] In order to solve the above problems, the present invention provides a battery SOC correction method, comprising: monitoring a target battery in a charging state; setting a correction counter and a preset cumulative value; cyclically judging whether the target battery meets the correction start condition in the current judgment step, and when the target battery meets the correction start condition in the current judgment step, the count value of the correction counter is increased by one; when the count value reaches the preset cumulative value, it is judged that the target battery meets the correction start condition, and the target battery enters the SOC correction process; according to the current characteristic data of the target battery, a current calibration value is obtained from a pre-established first experimental data table and a request current is requested to be sent to a charger; the response current received by the target battery is collected, and it is judged whether the current difference between the response current and the request current is within a threshold range; when the current difference is within the threshold range, according to the current characteristic data of the target battery, the SOC calibration value of the target battery is obtained from a pre-established second experimental data table, and the SOC correction value is updated accordingly; when the target battery meets the correction exit condition, the SOC value of the target battery is corrected by the SOC correction value, and the target battery exits the SOC correction process.

[0011] In some embodiments, when the target battery enters the SOC correction process, the count value of the correction counter is cleared.

[0012] In some embodiments, the correction start condition is that the voltage of each cell of the target battery is within a correction voltage range.

[0013] In some embodiments, the correction exit condition is that the voltage of at least one cell of the target battery exceeds the correction voltage range.

[0014] In some embodiments, the step of the target battery entering the SOC correction process further includes: setting a correction flag and assigning the correction flag to a valid value; after the target battery exits the SOC correction process, clearing the correction flag; and using whether the value of the correction flag is the valid value as a necessary condition for determining whether the target battery is in the SOC correction process.

[0015] In some embodiments, the current characteristic data includes a voltage and a temperature of the target battery.

[0016] In some embodiments, the first experimental data table includes the correspondence between voltage, temperature and current.

[0017] In some embodiments, the threshold range is between -1A and 1A.

[0018] In some embodiments, the second experimental data table includes a correspondence between voltage, temperature and SOC value.

[0019] The above technical solution, when the target battery is in a charging state, enters the SOC correction process when the target battery meets the correction start condition; obtains the current calibration value from a pre-established first experimental data table according to the current characteristic data of the target battery and uses it to request the charger to send a request current; when the current difference between the response current received by the target battery and the request current is within a threshold range, obtains the SOC calibration value of the target battery from a pre-established second experimental data table according to the current characteristic data of the target battery and updates the SOC correction value; when the target battery meets the correction exit condition, the SOC value of the target battery is corrected with the SOC correction value. The above method adjusts the estimated value of SOC when charging and not fully charged, thereby providing users with a more accurate battery management experience, and improves the intelligence level of the charging system when used for a long time and plugged in and unplugged.

[0020] It should be understood that the above general description and the detailed description below are exemplary and explanatory only and cannot limit the present invention. The techniques, methods and devices known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered as part of the authorization specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments of the present invention are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 is a flow chart of a battery SOC correction method provided by one embodiment of the present invention; Figure 2 It is a flowchart of the steps of determining whether the target battery meets the correction start condition provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The battery SOC correction method of the present invention is applicable to a battery in a charging state. During the execution of the battery SOC correction method, the battery is always being charged.

[0025] Figure 1 FIG. 1 is a flow chart of a battery SOC correction method provided by an embodiment of the present invention. Figure 1 As shown, the SOC correction method of the battery includes: step S11, monitoring the target battery in the charging state; step S12, judging whether the target battery meets the correction start condition, and when the target battery meets the correction start condition, the target battery enters the SOC correction process; step S13, according to the current characteristic data of the target battery, obtaining the current calibration value from the pre-established first experimental data table and using it to request the charger to send a request current; step S14, collecting the response current received by the target battery, and judging whether the current difference between the response current and the request current is within the threshold range; step S15, when the current difference is within the threshold range, according to the current characteristic data of the target battery, obtaining the SOC calibration value of the target battery from the pre-established second experimental data table, and using it to update the SOC correction value; step S16, judging whether the target battery meets the correction exit condition; step S17, when the target battery meets the correction exit condition, correcting the SOC value of the target battery with the SOC correction value, and the target battery exits the SOC correction process.

[0026] Referring to step S11, the target battery in the charging state is monitored. The battery SOC correction method of the present invention is applicable to the battery usage scenario of plug-and-play, and can correct the SOC estimation value of the target battery when the target battery is in the charging stage. If the target battery has reached a fully charged state or is in an idle state, it does not fall within the scope of application of this method and can be corrected by other means, for example, using SOC-OCV correction or fast correction.

[0027] In this embodiment, when the target battery is in a charging state, the current value of the target battery is monitored to be a negative value.

[0028] Referring to step S12, it is determined whether the target battery meets the correction start condition. When the target battery meets the correction start condition, the target battery enters the SOC correction process. When executing this step, it is ensured that the voltage reported by the charging report of the target battery is in a normal state. When the correction start condition is met, the target battery enters the SOC correction process. If the target battery does not meet the correction start condition, the target battery continues to charge until the target battery meets the correction start condition.

[0029] The battery SOC correction method of the present invention is applicable to a battery in a charging state. As charging proceeds, the characteristic data of the target battery changes continuously.

[0030] In this step, the step of judging whether the target battery meets the correction start condition further includes: setting a correction counter and a preset cumulative value; cyclically judging whether the target battery meets the correction start condition in the current judgment step, when the target battery meets the correction start condition in the current judgment step, the count value of the correction counter is increased by one; when the count value reaches the preset cumulative value, the target battery meets the correction start condition. The cyclic judgment can be carried out in a periodic cycle manner, triggering the judgment and executing the corresponding steps at a fixed time interval.

[0031] Figure 2 It is a flowchart of the steps of determining whether the target battery meets the correction start condition provided by an embodiment of the present invention.

[0032] like Figure 2As shown, the steps of judging whether the target battery satisfies the correction start condition include: step S121, setting a correction counter and a preset cumulative value; step S122, judging whether the target battery satisfies the correction start condition in the current judgment step; step S123, when the target battery satisfies the correction start condition in the current judgment step, the count value of the correction counter is increased by one; step S124, judging whether the count value reaches the preset cumulative value; step S125, when the count value reaches the preset cumulative value, the target battery satisfies the correction start condition.

[0033] Specifically, the execution of step S122 to step S124 is triggered at a fixed time interval, for example, the execution is triggered every 1ms; when the target battery does not meet the correction start condition in the current judgment step S122, wait to judge whether the target battery meets the correction start condition again in the next execution of judgment step S122; when the count value does not reach the preset cumulative value, wait to execute step S12 next time; when the count value reaches the preset cumulative value, the target battery meets the correction start condition and the cycle ends. Further, after the target battery meets the correction start condition, the count value of the correction counter is cleared.

[0034] In this embodiment, the initial value of the count value of the correction counter is set to zero, and the preset cumulative value is set to 1000.

[0035] In this embodiment, the correction start condition is that the voltage of each cell of the target battery is within the correction voltage range. The correction voltage range can be determined according to the charging experiment curve. For example, the correction voltage range is set to [3.30V, 3.35V]. When the voltage of each cell of the target battery is within the correction voltage range in step S122, the count value of the correction counter is increased by one.

[0036] This step finds a reasonable voltage region of the target battery in the charging platform area by setting the correction counter and the correction start condition, and then finds a reasonable SOC correction time. In addition, the method of setting the correction counter can also avoid erroneous triggering of the SOC correction process.

[0037] This step also sets a correction flag. When the target battery enters the SOC correction process, the correction flag is assigned a valid value. Whether the value of the correction flag is the valid value is used as a necessary condition for determining whether the target battery is in the SOC correction process.

[0038] In this embodiment, the initial value of the correction flag is 0, and the effective value is 1. Accordingly, when the target battery enters the SOC correction process, the correction flag is assigned a value of 1. When determining whether the target battery is in the SOC correction process, the value of the correction flag being 1 is a necessary condition.

[0039] Step S13, according to the current characteristic data of the target battery, obtain the current calibration value from the pre-established first experimental data table and use it to request the charger to send a request current. Wherein, the current characteristic data includes the voltage and temperature of the target battery.

[0040] The first experimental data table includes the corresponding relationship among voltage, temperature and current. The first experimental data table is generated according to experiments. For example, the effective range of the voltage range in the first experimental data table in this embodiment is divided into continuous intervals, namely [0mV, 2750mV), [2750mV, 2800mV), [2800mV, 2900mV), [2900mV, 3000mV), [3000mV, 3200mV), [3200mV, 3300mV), [3300mV, 3400mV), [3400mV, 3450mV), [3450mV, 3475mV), [3475mV, 3480mV), [3480mV, 3485mV) and greater than or equal to 3485mV. The effective range of the temperature range in the first experimental data table is divided into continuous intervals, namely [0°C, 2°C), [2°C, 7°C), [7°C, 15℃), [15℃, 20℃), [20℃, 25℃), [25℃, 35℃), [35℃, 40℃), [40℃, 45℃), [45℃, 50℃), [50℃, 55℃), [55℃, 56℃) and greater than or equal to 56℃. A table is formed with a continuous temperature range interval and a continuous voltage range interval to ensure that the corresponding current calibration value can be found in the table according to the voltage and temperature in the current characteristic data of the target battery. According to the voltage and temperature in the current characteristic data of the target battery, the temperature interval and voltage interval are matched from the first experimental data table to obtain the current calibration value corresponding to the current characteristic data. For example, if the voltage in the current characteristic data is 3481mV and the temperature is 42℃, the current calibration value obtained from the first experimental data table is 14A.

[0041] In this step, the battery management system (BMS) of the target battery sends a request to the charger based on a controller area network (CAN) protocol message, and sends a request current to the charger. The magnitude of the requested current is the current calibration value. In a specific embodiment, a battery charger link (BCL) message is used to send the request message to the charger.

[0042] In the battery SOC correction method, the target battery is in a charging state. As charging proceeds, the current characteristic data of the target battery is constantly changing. The current calibration value obtained by matching the current calibration value according to the current characteristic data can be dynamically adjusted. Especially at the end of battery charging, precise control of the current can avoid the problem of overcharging or undercharging the battery. The requested current is dynamically adjusted and the voltage is kept stable through BCL message acquisition, ensuring efficient charging management of the system. Compared with many existing fixed curve technical solutions, this has greater flexibility and accuracy.

[0043] Referring to step S14, the response current received by the target battery is collected to determine whether the current difference between the response current and the request current is within a threshold range. The response current is the current collected by the target battery after the charger sends a small charging current to the target battery according to the request current. If the current difference is not within the threshold range, step S13 may be continued until the current difference between the response current and the request current is within the threshold range in the determination of step S14.

[0044] In this embodiment, the threshold range is between -1A and 1A.

[0045] Referring to step S15, when the current difference is within the threshold range, the SOC calibration value of the target battery is obtained from a pre-established second experimental data table according to the current characteristic data of the target battery, and the SOC correction value is updated accordingly.

[0046] In this step, the second experimental data table includes the correspondence between voltage, temperature and SOC value. The second experimental data table can be generated by combining the experimental data table and the MAP table of the target battery.

[0047] This step may be performed multiple times, each time obtaining the current SOC calibration value from the second experimental data table according to the voltage and temperature in the current characteristic data of the target battery, and updating the SOC correction value according to the SOC calibration value.

[0048] Referring to step S16, it is determined whether the target battery meets the correction exit condition. When the target battery does not meet the correction exit condition, step S15 is continued.

[0049] Referring to step S17, the SOC value of the target battery is corrected with the SOC correction value, and the target battery exits the SOC correction process. In this step, the SOC correction value is the SOC correction value last updated in step S15.

[0050] In this embodiment, the correction start condition is that the voltage of each cell of the target battery is within the correction voltage range, and correspondingly, the correction exit condition is that the voltage of at least one cell of the target battery exceeds the correction voltage range. In specific judgment, the maximum and minimum values ​​of the voltages of all cells in the target battery are found, the correction start condition is that the maximum and minimum values ​​are both within the correction voltage range, and the correction exit condition is that the maximum and / or minimum value exceeds the correction voltage range.

[0051] As mentioned above, a correction flag is set in step S12. When the target battery enters the SOC correction process, the correction flag is assigned a valid value. Whether the value of the correction flag is the valid value is used as a necessary condition for determining whether the target battery is in the SOC correction process. Accordingly, in this step, when the target battery exits the SOC correction process, the correction flag is cleared.

[0052] The description of the above embodiment focuses on the execution process of the battery SOC correction method provided by the present invention under normal procedures. The absence of an abnormal processing procedure does not mean that there is no abnormal processing procedure in the above embodiment.

[0053] The above technical solution, when the target battery is in a charging state, when the target battery meets the correction start condition, it enters the SOC correction process; according to the current characteristic data of the target battery, a current calibration value is obtained from a pre-established first experimental data table and a request current is sent to the charger; when the current difference between the response current received by the target battery and the request current is within a threshold range, according to the current characteristic data of the target battery, the SOC calibration value of the target battery is obtained from a pre-established second experimental data table and the SOC correction value is updated; when the target battery meets the correction exit condition, the SOC value of the target battery is corrected with the SOC correction value. The above method adjusts the estimated value of SOC when charging and not fully charged, thereby providing users with a more accurate battery management experience, and improving the intelligence level of the charging system when used for a long time and plugged in and unplugged.

[0054] It should be noted that, in this document, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion. The various embodiments in this specification are described in a related manner, and the same and similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0055] The above is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. It should be noted that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A battery SOC correction method, characterized in that: include: Monitor the target battery's state of charge; Set correction counter and preset cumulative value; cyclically judging whether the target battery satisfies a correction start condition in a current judging step, and when the target battery satisfies the correction start condition in the current judging step, the count value of the correction counter is increased by one; When the count value reaches the preset cumulative value, it is determined that the target battery meets the correction start condition, and the target battery enters the SOC correction process; according to the current characteristic data of the target battery, a current calibration value is obtained from a pre-established first experimental data table and a request current is sent to the charger; Collect the response current received by the target battery, and determine whether the current difference between the response current and the request current is within a threshold range; when the current difference is within the threshold range, obtain the SOC calibration value of the target battery from a pre-established second experimental data table based on the current characteristic data of the target battery, and update the SOC correction value accordingly; when the target battery meets the correction exit condition, correct the SOC value of the target battery with the SOC correction value, and the target battery exits the SOC correction process.

2. The method according to claim 1, characterized in that When the target battery enters the SOC correction process, the count value of the correction counter is reset.

3. The method according to claim 1, characterized in that The correction start condition is that the voltage of each cell of the target battery is within a correction voltage range.

4. The method according to claim 3, characterized in that The correction exit condition is that the voltage of at least one cell of the target battery exceeds the correction voltage range.

5. The method according to claim 1, characterized in that The step of the target battery entering the SOC correction process further includes: setting a correction flag and assigning the correction flag to a valid value; after the target battery exits the SOC correction process, clearing the correction flag; and using whether the value of the correction flag is the valid value as a necessary condition for determining whether the target battery is in the SOC correction process.

6. The method according to claim 1, characterized in that The current characteristic data includes a voltage and a temperature of the target battery.

7. The method according to claim 1, characterized in that The first experimental data table includes the corresponding relationship among voltage, temperature and current.

8. The method according to claim 1, characterized in that The threshold range is between -1A and 1A.

9. The method according to claim 1, characterized in that: The second experimental data table includes the correspondence between voltage, temperature and SOC value.

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