Calibration method for soc, micro control unit and battery management system

Abstract

The application provides a calibration method of an SOC, a micro control unit and a battery management system. The calibration method comprises the following steps: calibrating the total available electric quantity of a lithium battery by using a preset factor to obtain a calibrated total electric quantity, and calibrating the current SOC value by using the calibrated total electric quantity, wherein the preset factor comprises at least one of the following: the current SOC value, the charging frequency, the dynamic reserved electric quantity and the temperature; calibrating the residual electric quantity of the lithium battery by using a preset condition to obtain a calibrated residual electric quantity, and calibrating the current SOC value by using the calibrated residual electric quantity, wherein the preset condition comprises at least one of the following: a fullness judging condition and a discharging factor, and the fullness judging condition is used to represent whether the residual electric quantity reaches the full residual electric quantity, and the full residual electric quantity is the sum of the total available electric quantity and the dynamic reserved electric quantity, thereby solving the problem that the SOC value is difficult to be estimated accurately in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium battery, in particular to a SOC calibration method, a micro control unit, a computer readable storage medium, a processor and a battery management system. BACKGROUND

[0002] High-precision state of charge (SOC) estimation is one of the key technologies of a battery management system (BMS). In the prior art, SOC is estimated by using an ampere-hour integration method, an open-circuit voltage method, an internal resistance method, a neural network and a Kalman filtering method. The ampere-hour integration method, also known as a current integration method or a coulomb counting method, is widely used in estimating the SOC of a lithium battery. However, the state of charge of the battery is affected by the discharge current, the internal temperature of the battery, self-discharge, aging and other factors. The accuracy of each algorithm design, hardware circuit and current sampling chip selection is different, so the algorithm is easily affected by the aging degree of the battery, the current temperature of the battery pack and the performance of the hardware sampling circuit. Long-term use will cause accumulated errors. The open-circuit voltage method requires a long time to stand the battery pack, so the estimation accuracy of the above-mentioned SOC estimation methods is poor.

[0003] Therefore, there is an urgent need for a method for more accurately estimating SOC. SUMMARY

[0004] The main purpose of the present application is to provide a SOC calibration method, a micro control unit, a computer readable storage medium, a processor and a battery management system to solve the problem that it is difficult to accurately estimate the SOC value in the prior art.

[0005] According to one aspect of an embodiment of the present application, a SOC calibration method is provided, which includes: using a preset factor to calibrate the total available electric quantity of a lithium battery to obtain a calibrated total electric quantity, and using the calibrated total electric quantity to calibrate the current SOC value, the preset factor including at least one of the following: the current SOC value, the number of charging times, a dynamic reserved electric quantity, a temperature; using a preset condition to calibrate the residual electric quantity of the lithium battery to obtain a calibrated residual electric quantity, and using the calibrated residual electric quantity to calibrate the current SOC value, the preset condition including at least one of the following: a fullness judgment condition and a discharge factor, the fullness judgment condition being used to represent whether the residual electric quantity reaches a full residual electric quantity, the full residual electric quantity being the sum of the total available electric quantity and the dynamic reserved electric quantity.

[0006] Optionally, the lithium battery comprises a battery pack including a plurality of single batteries, and a preset factor is used to calibrate a total available electric quantity of the lithium battery to obtain a calibrated total electric quantity, including: in a case that the lithium battery is in a discharging state and a preset discharging condition is met, calculating a product of an open circuit SOC value and the total available electric quantity to obtain a current residual electric quantity, and calculating a sum of a single discharging quantity of the battery pack and the current residual electric quantity to obtain a preset total electric quantity, the open circuit SOC value is calculated by using an open circuit voltage method, the single discharging quantity is calculated by using an ampere-hour integration method, and the preset discharging condition includes that the battery pack is in a full state, the current residual electric quantity is greater than or equal to the total available electric quantity, a current discharging current is within a preset discharging current range, a current discharging temperature is within a preset discharging temperature range, and an open circuit voltage value of the single battery is equal to a first open circuit voltage threshold; calculating a difference between the preset total electric quantity and the total available electric quantity to obtain a target difference; and according to the target difference and a target difference range, the total available electric quantity is calibrated to obtain the calibrated total electric quantity.

[0007] Optionally, the target difference range includes a target difference upper limit and a target difference lower limit, and according to the target difference and the target difference range, the total available electric quantity is calibrated to obtain the calibrated total electric quantity, including: in a case that the target difference is greater than or equal to the target difference upper limit, the total available electric quantity is updated as a sum of the preset total electric quantity and the target difference upper limit to obtain the calibrated total electric quantity; in a case that the target difference is less than or equal to the target difference lower limit, the total available electric quantity is updated as a difference between the preset total electric quantity and the target difference lower limit to obtain the calibrated total electric quantity; and in a case that the target difference is within the target difference range, the total available electric quantity is updated as the preset total electric quantity to obtain the calibrated total electric quantity.

[0008] Optionally, a preset factor is used to calibrate a total available electric quantity of the lithium battery to obtain a calibrated total electric quantity, including: determining a total charging number of the lithium battery and a change threshold, the change threshold being a change threshold of the total available electric quantity when the lithium battery is charged each time; calculating a product of the total charging number and the change threshold to obtain a target change threshold; and calculating a difference between the current total available electric quantity and the target change threshold to obtain the calibrated total electric quantity.

[0009] Optionally, the total available power of the lithium battery is calibrated by using a preset factor to obtain a calibrated total power, including: calculating a product of a first predetermined value and a total charging times to obtain a first target value, and calculating a product of a second predetermined value and a minimum discharging temperature to obtain a second target value; calculating a sum of a dynamic reserved power initial value, the first target value and the second target value to obtain the dynamic reserved power; calculating a difference between the total available power and the dynamic reserved power to obtain the calibrated total power.

[0010] Optionally, the total available power of the lithium battery is calibrated by using a preset factor to obtain a calibrated total power, including: in a case that a current ambient temperature of the lithium battery is lower than a preset temperature value, determining a low-temperature compensation power; updating the total available power by using a difference between a current actual total available power of the lithium battery and the low-temperature compensation power to obtain the calibrated total power.

[0011] Optionally, the lithium battery includes a battery pack, and the remaining power of the lithium battery is calibrated by using a preset condition to obtain a calibrated remaining power, including: in a case that the lithium battery is in a charging state, determining whether a current charging state reaches a full state and whether a current remaining power reaches a full remaining power according to at least the current charging state, the current remaining power and a fullness determination condition, the full state being determined based on a charging current, a charging voltage of the battery pack and a charging power within a preset time; in a case that the current charging state reaches the full state and the current remaining power reaches the full remaining power, determining the full remaining power as the calibrated remaining power.

[0012] Optionally, in a case that the lithium battery is in a charging state, whether a current charging state reaches a full state and whether a current remaining power reaches a full remaining power are determined according to at least the current charging state, the current remaining power and a fullness determination condition, including: determining whether the current charging state reaches a quasi-full state and whether the current remaining power reaches a quasi-full remaining power according to at least the current charging state, the current remaining power and a quasi-fullness determination condition, the quasi-full remaining power being a product of the total available power and a third target value, the third target value being less than 1, the quasi-full state being determined based on a charging current, a charging voltage of the battery pack and a charging power within a preset time, the quasi-full state and the full state being two different states; in a case that the current charging state reaches the quasi-full state and the current remaining power reaches the quasi-full remaining power, determining whether the current charging state reaches the full state and whether the current remaining power reaches the full remaining power according to at least the current charging state, the current remaining power and the fullness determination condition again.

[0013] Optionally, after determining whether the current charging state reaches the quasi-full state and whether the current remaining capacity reaches the quasi-full remaining capacity according to at least the current charging state, the current remaining capacity and the quasi-judgment full condition, the calibration method further comprises: in the case that the current charging state does not reach the quasi-full state and the current remaining capacity is less than the quasi-full remaining capacity, controlling the lithium battery to continue charging and using the ampere-hour integration method to continue calculating the current remaining capacity until the current charging state reaches the quasi-full state and the current remaining capacity reaches the quasi-full remaining capacity; in the case that the current charging state does not reach the quasi-full state and the current remaining capacity is equal to the quasi-full remaining capacity, controlling the lithium battery to continue charging until the current charging state reaches the quasi-full state; in the case that the current charging state reaches the quasi-full state and the current remaining capacity is less than the quasi-full remaining capacity, controlling the lithium battery to continue charging and using the ampere-hour integration method to continue calculating the remaining capacity until the remaining capacity reaches the quasi-full remaining capacity.

[0014] Optionally, after determining whether the current charging state reaches the full state and whether the current remaining capacity reaches the full remaining capacity according to at least the current charging state, the current remaining capacity and the judgment full condition, the calibration method further comprises: in the case that the current charging state does not reach the full state and the current remaining capacity is less than or equal to the full remaining capacity, controlling the lithium battery to continue charging until the charging state reaches the full state and the remaining capacity reaches the full remaining capacity.

[0015] Optionally, the remaining capacity of the lithium battery is calibrated by using a preset condition to obtain a calibrated remaining capacity, comprising: in the case that the lithium battery is in a discharging state or a static state, calculating the difference between the actual total available capacity, the single discharging capacity and the self-consumption capacity to obtain the calibrated remaining capacity, wherein the single discharging capacity is determined based on at least a discharging factor; in the case that the lithium battery is in a charging state, calculating the difference between the current remaining capacity and the self-consumption capacity to obtain the calibrated remaining capacity.

[0016] Optionally, the lithium battery comprises a battery pack including a plurality of single batteries, and the process of determining the discharge factor corresponding to the single-discharge electric quantity in the case that the lithium battery is in a discharging state comprises: determining whether the ampere-hour integral residual electric quantity is greater than the open-circuit voltage residual electric quantity in the case that the open-circuit voltage value of the single battery is equal to a second open-circuit voltage threshold; calculating a difference value between the ampere-hour integral residual electric quantity and the open-circuit voltage residual electric quantity to obtain a residual electric quantity difference value in the case that the ampere-hour integral residual electric quantity is greater than the open-circuit voltage residual electric quantity; calculating a ratio of the residual electric quantity difference value to the open-circuit voltage residual electric quantity to obtain a first adjustment coefficient, and calculating a product of the current discharge factor and the first adjustment coefficient to obtain an adjusted discharge factor.

[0017] Optionally, the lithium battery comprises a battery pack including a plurality of single batteries, and the process of determining the discharge factor corresponding to the single-discharge electric quantity in the case that the lithium battery is in a discharging state comprises: determining whether the ampere-hour integral residual electric quantity is greater than the open-circuit voltage residual electric quantity in the case that the open-circuit voltage value of the single battery is equal to a third open-circuit voltage threshold; calculating a sum of the current discharge factor and an acceleration factor to obtain an adjusted discharge factor in the case that the ampere-hour integral residual electric quantity is greater than the open-circuit residual voltage electric quantity.

[0018] Optionally, the lithium battery comprises a battery pack, and the process of determining the self-consumption electric quantity comprises: obtaining the self-consumption electric quantity, wherein DC self is the self-consumption electric quantity, I self is the self-consumption electric quantity, I Ssysself is the self-consumption electric quantity, I battself is the self-consumption electric quantity, I Ssysself is an estimated value of the self-air discharge of the battery pack, and I battself is an estimated value of the self-loop loss current of the battery pack.

[0019] Optionally, the current SOC value is corrected by using the calibrated residual electric quantity, comprising: updating the SOC value to 100% in the case that the calibrated residual electric quantity reaches the total available electric quantity.

[0020] According to another aspect of the embodiments of the present application, a micro control unit is also provided, which comprises: a first calibration unit configured to calibrate the total available capacity of the lithium battery by using a preset factor, to obtain a calibrated total capacity, and to calibrate the current SOC value by using the calibrated total capacity, wherein the preset factor comprises at least one of the current SOC value, the number of charging times, the dynamic reserved capacity, and the temperature; and a second calibration unit configured to calibrate the remaining capacity of the lithium battery by using a preset condition, to obtain a calibrated remaining capacity, and to calibrate the current SOC value by using the calibrated remaining capacity, wherein the preset condition comprises at least one of a fullness judging condition and a discharge factor, and the fullness judging condition is used to represent whether the remaining capacity reaches a full remaining capacity, and the full remaining capacity is the sum of the total available capacity and the dynamic reserved capacity.

[0021] According to still another aspect of the embodiments of the present application, a computer readable storage medium is also provided, which comprises a stored program, wherein the program performs any one of the SOC calibration methods.

[0022] According to still another aspect of the embodiments of the present application, a processor is also provided, which is used to run a program, wherein the program performs any one of the SOC calibration methods when running.

[0023] According to an aspect of the embodiments of the present application, a battery management system is also provided, which comprises a micro control unit and a lithium battery, and the micro control unit is configured to perform any one of the SOC calibration methods.

[0024] In the SOC calibration method, the current SOC value, the number of charging times, the dynamic reserved capacity, or the temperature is used to calibrate the total available capacity of the lithium battery, to obtain a calibrated total capacity, and the calibrated total capacity is used to correct the current SOC value. The fullness judging condition or the discharge factor is used to calibrate the remaining capacity of the lithium battery, to obtain a calibrated remaining capacity, and the calibrated remaining capacity is used to calibrate the current SOC value. In the calibration method, the influence of the current SOC value, the number of charging times, the dynamic reserved capacity, or the temperature on the total available capacity of the lithium battery is considered to calibrate the total available capacity, to obtain a calibrated total capacity, and the influence of whether the current remaining capacity reaches a full remaining capacity or the discharge factor on the remaining capacity of the lithium battery is considered to calibrate the remaining capacity. This ensures that the obtained SOC value of the lithium battery is relatively accurate, avoids the situation that the SOC value suddenly changes during the operation of the vehicle, ensures the stability of the battery management system, and ensures that the user has a good experience, thereby solving the problem that it is difficult to accurately estimate the SOC value in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this specification. The embodiments of this application, and of the

[0026] Figure 1 A flow chart of a calibration method of a SOC according to an embodiment of the application is shown;

[0027] Figure 2 A schematic diagram of open circuit voltage change during discharging according to an embodiment of the application is shown;

[0028] Figure 3 A schematic diagram of relationship between discharging temperature and discharging capacity according to an embodiment of the application is shown;

[0029] Figure 4 A structural schematic diagram of a micro control unit according to an embodiment of the application is shown.

[0030] Wherein, the above-mentioned drawings include the following reference signs:

[0031] 100, first open circuit voltage threshold; 200, third open circuit voltage threshold; 300, second open circuit voltage threshold. DETAILED DESCRIPTION

[0032] It should be noted that the embodiments and features in the application can be combined with each other without conflict. The application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0033] In order to enable persons skilled in the art to better understand the application scheme, the technical solutions in the embodiments of the application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by persons skilled in the art without creative labor should belong to the protection scope of the application.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0035] As mentioned in the background, it is difficult to accurately estimate the SOC in the prior art. In order to solve the above problems, in a typical embodiment of the present application, a SOC calibration method, a micro control unit, a computer readable storage medium, a processor and a battery management system are provided.

[0036] According to an embodiment of the present application, a SOC calibration method is provided.

[0037] Figure 1 is a flowchart of the SOC calibration method according to an embodiment of the present application. As shown in Figure 1 , the calibration method comprises the following steps:

[0038] Step S101, calibrating the total available power of the lithium battery by using a preset factor to obtain a calibrated total power, and calibrating the current SOC value by using the calibrated total power, wherein the preset factor includes at least one of the following: the current SOC value, the number of charging times, the dynamic reserved power, and the temperature;

[0039] Step S102, calibrating the remaining power of the lithium battery by using a preset condition to obtain a calibrated remaining power, and calibrating the current SOC value by using the calibrated remaining power, wherein the preset condition includes at least one of the following: a full condition and a discharge factor, the full condition is used to represent whether the remaining power reaches a full remaining power, and the full remaining power is the sum of the total available power and the dynamic reserved power.

[0040] The calibration method of the SOC described above, using the current SOC value, the number of charges, the dynamic reserved capacity or the temperature, calibrates the total available capacity of the lithium battery to obtain a calibrated total capacity, and then uses the calibrated total capacity to correct the current SOC value. The remaining capacity of the lithium battery is calibrated using the full remaining capacity condition or the discharge factor to obtain a calibrated remaining capacity, and then the calibrated remaining capacity is used to calibrate the current SOC value. In the calibration method of the present application, the influence of the current SOC value, the number of charges, the dynamic reserved capacity or the temperature on the total available capacity of the lithium battery is considered to calibrate the total available capacity to obtain a calibrated total capacity, and the influence of whether the current remaining capacity reaches the full remaining capacity or the discharge factor on the remaining capacity of the lithium battery is considered to calibrate the remaining capacity. This ensures that the obtained SOC value of the lithium battery is relatively accurate, avoids the situation that the SOC value suddenly changes during the operation of the vehicle, ensures the stability of the battery management system, and ensures that the user has a good use experience, thereby solving the problem that it is difficult to accurately estimate the SOC value in the prior art.

[0041] In actual application process, in some special scenarios, for example, after the lithium battery is initially put into use after leaving the factory, the following method can be used to calculate the SOC value. Specifically, the discharge temperature and discharge current are determined after the battery pack is fully charged, and the discharge capacity is the same each time. After standing for a predetermined time, the data is recorded. Repeat the above process and change the discharge current from 1A to 8A and the discharge temperature from -5°C to 65°C. Among them, every 1A is as a gear, and every 10°C is as a gear. The internal resistance of the battery cell is calculated. The BMS (Battery Management System, BMS for short) will calculate the open circuit voltage V OCV

[0042] V OCV = f(V CELL , T CELL , I CELL , DCIR OCV ),

[0043] wherein V CELL is the voltage of the single battery in the battery pack, T CELL is the discharge temperature of the single battery, I CELL is the discharge current of the single battery, and DCIR OCV is the internal resistance of the single battery. Specifically, the determination method of V CELL is

[0044] V CELL = V CELLpack -ICELL xR0,

[0045] wherein, V CELLpack is the actual voltage of the single battery collected by the BMS system, R0is the resistance between the internal series nodes of the battery pack. Specifically, the determination method of DCIR OCV is

[0046] DCIR OCV = f(V CELL , I CELL , T CELL ).

[0047] Then, according to the open circuit voltage V OCV and the discharge temperature T CELL , the remaining capacity RC OCVcell is calculated, and then

[0048] RC OCVcell = f(V OCV , T CELL ).

[0049] According to the current actual estimated total available capacity FCC and the open circuit voltage method, the SOC value is calculated, specifically

[0050]

[0051] wherein, Npal is the number of parallel single batteries in the battery pack, RC OCVcell-i is the remaining capacity of the i-th single battery.

[0052] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from here.

[0053] In the actual application process, after the lithium battery is discharged and charged for many times, the total available capacity of the lithium battery will change, for example, with the use of the lithium battery, the total available capacity of the lithium battery will be smaller and smaller than the total available capacity of the lithium battery when it is first put into use. Therefore, in order to make the total available capacity of the lithium battery more accurate, further ensure that the obtained SOC value is more accurate, in an embodiment of the present application, for example, Figure 2The lithium battery includes a battery pack, the battery pack includes a plurality of single batteries, and a total available electric quantity of the lithium battery is calibrated by a preset factor to obtain a calibrated total electric quantity. In a case where the lithium battery is in a discharging state and a preset discharging condition is met, a product of an open circuit SOC value (i.e., a current SOC value of the lithium battery) and the total available electric quantity is calculated to obtain a current residual electric quantity, and a sum of a single discharging electric quantity of the battery pack and the current residual electric quantity is calculated to obtain a preset total electric quantity. The open circuit SOC value is calculated by an open circuit voltage method, the single discharging electric quantity is calculated by an ampere-hour integration method, and the preset discharging condition includes that the battery pack is in a full state, the current residual electric quantity is greater than or equal to the total available electric quantity, a current discharging current is within a preset discharging current range, a current discharging temperature is within a preset discharging temperature range, and an open circuit voltage value of the single battery is equal to a first open circuit voltage threshold 100. A difference between the preset total electric quantity and the total available electric quantity is calculated to obtain a target difference. The target difference and a target difference range are used to calibrate the total available electric quantity to obtain the calibrated total electric quantity.

[0054] In another embodiment of the present application, the target difference range includes a target difference upper limit and a target difference lower limit. The target difference and the target difference range are used to calibrate the total available electric quantity to obtain the calibrated total electric quantity. In a case where the target difference is greater than or equal to the target difference upper limit, the total available electric quantity is updated to a sum of the preset total electric quantity and the target difference upper limit to obtain the calibrated total electric quantity. In a case where the target difference is less than or equal to the target difference lower limit, the total available electric quantity is updated to a difference between the preset total electric quantity and the target difference lower limit to obtain the calibrated total electric quantity. In a case where the target difference is within the target difference range, the total available electric quantity is updated to the preset total electric quantity to obtain the calibrated total electric quantity. This ensures that the total available electric quantity can be calibrated simply, and the calibrated total electric quantity is used to calibrate the SOC value, further ensuring that the obtained SOC value is more accurate.

[0055] In a specific embodiment of the present application, the preset total electric quantity FCC LEARN == DC AH + SOC OCV × FCC, where DC AH is a single discharging electric quantity obtained by an ampere-hour integration method, SOC OCV is an open circuit SOC value obtained by an open circuit voltage method, i.e., a current SOC value, and FCC is a total available electric quantity. Then, a target difference = FCC LEARN - FCC is calculated. In a case where FCC LEARN - FCC ≥ FCC LEARN-thresholdmaxIn the case of calibrating total power consumption, FCC 校准 =FCC LEARN +FCC LEARN-thresholdmax In the FCC LEARN -FCC≤FCC LEARN-thresholdmin In the case of total calibrated power (FCC) 校准 =FCC LEARN -FCC LEARN-thresholdmin Among them, FCC LEARN-thresholdmax The upper limit of the target difference, FCC LEARN-thresholdmin This is the lower limit of the target difference. (In the FCC) LEARN -FCC is in [FCC LEARN-thresholdmin FCC LEARN-thresholdmax In the case of […], the FCC 校准 =FCC LEARN This ensures that the total calibration power obtained is neither less than nor greater than the total available power, thus guaranteeing that the total calibration power obtained is relatively accurate.

[0056] In practical applications, the above-mentioned preset discharge conditions can also be the standard discharge mode, specifically, as follows: Figure 2 As shown, the current state of charge (Currsaturated) of the above battery pack is fully charged (i.e., Mainsaturated), CC AH ≥FCC (Current remaining battery power is greater than or equal to total available battery power), I minqualified ≤I PACK ≤I maxqualified (The current discharge current is within the preset discharge current range), T minqualified ≤T PACK ≤T maxqualified (The current discharge temperature is within the preset discharge temperature range) and V minOCVofCELL =V cent1ofCELL (The open-circuit voltage of a single cell is equal to the first open-circuit voltage threshold of 100).

[0057] Specifically, during the calibration of the total available power, if the FCC value of the total available power decreases, the SOH (State of Health) value is immediately updated, indicating that the battery's health status is gradually declining.

[0058] In yet another embodiment of the present application, the total available capacity of the lithium battery is calibrated by using a preset factor to obtain a calibrated total capacity, comprising: determining the total number of charging times of the lithium battery and a change threshold, the change threshold being the change threshold of the total available capacity of the lithium battery at each charging time; calculating the product of the total number of charging times and the change threshold to obtain a target change threshold; and calculating the difference between the current total available capacity and the target change threshold to obtain the calibrated total capacity. In actual application, as the number of charging times increases, the total available capacity of the lithium battery will gradually decrease, so in this embodiment, the total number of charging times is used to calibrate the total available capacity, which ensures that the calibrated total capacity is more accurate.

[0059] Specifically, since the lithium batteries of different manufacturers have different change thresholds, the size of the change threshold is not limited in the present application, and can be flexibly adjusted according to the situation of the lithium battery.

[0060] In a specific embodiment of the present application, the total number of charging times Timer dc is a function of the total available capacity FCC, so the target change threshold can be Timer dc × FCC, so that the calibrated total capacity FCC 校准 = FCC PRE -Timer dc × FCC, FCC PRE is the current total available capacity, and FCC PRE > Timer dc × FCC.

[0061] In actual application, in order to ensure that the lithium battery still maintains a certain amount of power after the SOC is 0, so that the BMS system can work normally, further ensuring the stability of the BMS system and the normal work of other circuits, in another embodiment of the present application, the total available capacity of the lithium battery is calibrated by using a preset factor to obtain a calibrated total capacity, comprising: calculating the product of a first predetermined value and the total number of charging times to obtain a first target value, and calculating the product of a second predetermined value and the minimum discharge temperature to obtain a second target value; calculating the sum of the dynamic reserved initial capacity, the first target value and the second target value to obtain the dynamic reserved capacity; and calculating the difference between the total available capacity and the dynamic reserved capacity to obtain the calibrated total capacity.

[0062] Specifically, through experiments, it is known that the dynamic reserved capacity Q REV is a bivariate linear function of the total number of charging times and the discharge temperature, so Q REV = f(Timer dc , T min) = Q0 + a x Timer dc + b x T min , where a is a first predetermined value, Timer dc is a total number of charging, b is a second predetermined value, T min is a minimum discharging temperature, Q0 is an initialized reserved capacity of the lithium battery when it is manufactured, and a and b can be set according to a calibration test before the lithium battery is manufactured, and then there is a calibrated total capacity FCC 校准 = FCC - Q REV .

[0063] In an embodiment of the present application, a preset factor is used to calibrate the total available capacity of the lithium battery to obtain a calibrated total capacity, including: determining a low-temperature compensation capacity when the current ambient temperature of the lithium battery is lower than a preset temperature value; updating the total available capacity by using the difference between the current actual total available capacity of the lithium battery and the low-temperature compensation capacity to obtain the calibrated total capacity. In this embodiment, the influence of low temperature on the total available capacity of the lithium battery is considered, so that the calibrated total capacity obtained is more accurate, and the SOC value obtained subsequently is further ensured to be more accurate.

[0064] In a specific embodiment of the present application, FCC 校准 = FCC pack - f (T < T LOWTemp ), where FCC pack is an actual total available capacity, and f (T < T LOWTemp ) is a low-temperature compensation function, by which a low-temperature compensation capacity can be determined. In addition, in the above embodiment, the preset temperature value can be 5°C. Of course, the preset temperature value is not limited to 5°C, and can also be other temperature values, and the specific size can be adjusted according to the actual situation of the lithium battery.

[0065] Specifically, in the present application, the discharge capacity of the lithium battery under different currents at different discharging temperatures is tested, and the minimum value is taken as the calculation value, and the maximum available capacity in theory is calculated by the difference method, to obtain the relationship between the discharging temperature and the discharge capacity as shown in Figure 3 .

[0066] In actual application process, in order to protect lithium battery, the charger is usually disconnected to stop charging when the battery pack is full. In this case, if the current remaining power is less than the total available power, it will cause the lithium battery to be unable to be fully charged, that is, the SOC value of the lithium battery is forced to be set to 100%, and in the subsequent discharging process of the lithium battery, a sudden change will occur. If the current remaining power has reached the total available power, but has not reached the preset full condition, the SOC value will be greater than 100%. The above two cases will bring bad user experience to the user. Therefore, in order to avoid the above situation of the lithium battery, in another embodiment of the present application, the above lithium battery includes a battery pack, and the remaining power of the above lithium battery is calibrated by using a preset condition to obtain a calibrated remaining power, comprising: in the case that the above lithium battery is in a charging state, at least according to the current charging state, the current remaining power and the full condition, it is determined whether the current charging state reaches the full state and whether the current remaining power reaches the full remaining power, the full state is determined based on the charging current, the charging voltage of the above battery pack and the charging power in the preset time; in the case that the current charging state reaches the full state and the current remaining power reaches the full remaining power, the full remaining power is determined as the calibrated remaining power.

[0067] In another embodiment of the present application, when the lithium battery is in the charging state, whether the current charging state reaches the full state and whether the current remaining capacity reaches the full remaining capacity are determined according to at least the current charging state, the current remaining capacity and the saturation condition, including: determining whether the current charging state reaches the quasi-full state and whether the current remaining capacity reaches the quasi-full remaining capacity according to at least the current charging state, the current remaining capacity and the quasi-saturation condition, the quasi-full remaining capacity being the product of the total available capacity and a third target value, the third target value being less than 1, the quasi-full state being determined based on the charging current, the charging voltage of the battery pack and the charging capacity within a preset time, and the quasi-full state and the full state being two different states; and when the current charging state reaches the quasi-full state and the current remaining capacity reaches the quasi-full remaining capacity, determining whether the current charging state reaches the full state and whether the current remaining capacity reaches the full remaining capacity according to at least the current charging state, the current remaining capacity and the saturation condition. In this embodiment, the current charging state and the current remaining capacity are first determined according to the quasi-saturation condition to determine whether the current charging state reaches the quasi-full state and whether the current remaining capacity reaches the quasi-full remaining capacity, and when the current charging state reaches the quasi-full state and the current remaining capacity reaches the quasi-full remaining capacity, the current charging state and the current remaining capacity are determined according to the saturation condition to determine whether the current charging state reaches the full state and whether the current remaining capacity reaches the full remaining capacity. This ensures that the current charging state and the current remaining capacity can be accurately determined, further avoids the sudden change of the SOC value of the lithium battery, and further ensures a good user experience.

[0068] In a specific embodiment of the present application, the third target value can be 0.99, i.e., the quasi-full remaining capacity can be represented as 0.99xFCC. Of course, in actual application, the third target value is not limited to 0.99, and the third target value can also be other suitable values less than 1.

[0069] In order to further ensure that the current charging state of the lithium battery reaches the quasi-saturated state and the current remaining capacity reaches the quasi-full remaining capacity, in another embodiment of the present application, after determining whether the current charging state reaches the quasi-full state and whether the current remaining capacity reaches the quasi-full remaining capacity according to the current charging state, the current remaining capacity and the quasi-saturation condition, the calibration method further comprises: in the case that the current charging state does not reach the quasi-full state and the current remaining capacity is less than the quasi-full remaining capacity, controlling the lithium battery to continue charging and using the ampere-hour integration method to continue calculating the current remaining capacity until the current charging state reaches the quasi-full state and the current remaining capacity reaches the quasi-full remaining capacity; in the case that the current charging state does not reach the quasi-full state and the current remaining capacity is equal to the quasi-full remaining capacity, controlling the lithium battery to continue charging until the current charging state reaches the quasi-full state; in the case that the current charging state reaches the quasi-full state and the current remaining capacity is less than the quasi-full remaining capacity, controlling the lithium battery to continue charging and using the ampere-hour integration method to continue calculating the current remaining capacity until the current remaining capacity reaches the quasi-full remaining capacity.

[0070] In actual application, in the case that the current charging state (Currsaturated) does not reach the quasi-full state (Subsaturated) and the current remaining capacity is less than the quasi-full remaining capacity (CC AH <0.99×FCC), the lithium battery is controlled to continue charging and the current remaining capacity is calculated, i.e. until the current charging state (Currsaturated) reaches the quasi-full state (Subsaturated) and the current remaining capacity reaches the quasi-full remaining capacity (CC AH =0.99×FCC). In the case that the current charging state (Currsaturated) does not reach the quasi-full state (Subsaturated) and the current remaining capacity is equal to the quasi-full remaining capacity (CC AH =0.99×FCC), the lithium battery is controlled to continue charging until the charging state (Currsaturated) reaches the quasi-full state (Subsaturated). In the case that the current charging state (Currsaturated) reaches the quasi-full state (Subsaturated) and the current remaining capacity is less than the quasi-full remaining capacity (CC AH <0.99×FCC), the lithium battery is controlled to continue charging and the current remaining capacity is calculated, i.e. until the current remaining capacity reaches the quasi-full remaining capacity (CCAH = 0.99 x FCC).

[0071] In one embodiment of the present application, after determining whether the current state of charge reaches the full state of charge and whether the current remaining capacity reaches the full remaining capacity according to the current state of charge, the current remaining capacity and the full state condition, the calibration method further comprises: in the case that the current state of charge does not reach the full state of charge and the current remaining capacity is less than or equal to the full remaining capacity, controlling the lithium battery to continue charging until the state of charge reaches the full state of charge and the remaining capacity reaches the full remaining capacity. In this embodiment, the remaining capacity of the lithium battery is controlled to reach the full remaining capacity, so that the lithium battery has a dynamic reserved capacity, and the lithium battery can still be used for a shorter period of time when the battery capacity is low, i.e. the SOC value is low, and will not suddenly power off, which can ensure a good user experience.

[0072] In actual application, in the case that the current state of charge (Currsaturated) does not reach the full state of charge (Main saturated) and the current remaining capacity is less than or equal to the full remaining capacity (CC AH ≤ FCC + Q REV ), the lithium battery is controlled to continue charging and the current remaining capacity is calculated, i.e. until the current state of charge (Currsaturated) reaches the full state of charge (Main saturated) and the current remaining capacity is equal to the full remaining capacity (CC AH = FCC + Q REV ).

[0073] Specifically, when the current remaining capacity CC AH reaches FCC + Q REV , the SOC value is set to 100%, i.e. after the SOC value is 100%, even if the lithium battery continues to charge, the SOC value will not continue to increase. When the BMS system starts discharging, CC AH = FCC.

[0074] Specifically, after the current remaining capacity CC AH > FCC, since the SOC value will be greater than 100% at this time, the above situation is not allowed in actual application, so the SOC value is set to 100% and will not change. After the lithium battery starts discharging, the current remaining capacity CC AH= FCC, the BMS system starts the discharge counting. That is, more dynamic reserved power is stored in the lithium battery, and when the remaining power of the lithium battery is small, for example, the SOC value is less than 5%, the lithium battery can still work for a long time and will not be powered off quickly, further ensuring that the user has a good experience.

[0075] In order to further ensure that the obtained calibrated remaining power is accurate, in another embodiment of the present application, a preset condition is used to calibrate the remaining power of the lithium battery to obtain the calibrated remaining power, including: in the case that the lithium battery is in a discharge state or a static state, calculating the difference between the actual total available power, the single discharge power and the self-consumption power to obtain the calibrated remaining power, wherein the single discharge power is determined based on at least the discharge factor; in the case that the lithium battery is in a charging state, calculating the difference between the current remaining power and the self-consumption power to obtain the calibrated remaining power.

[0076] Specifically, in the case that the lithium battery is in a discharge state or a static state, the calibrated remaining power is

[0077]

[0078] Wherein, RC AH is the calibrated remaining power, FCC pack is the actual total available power, DC AH is the single discharge power, DC self is the self-consumption power, F is the discharge factor, I pack is the actual discharge current, I self is the self-consumption current.

[0079] Specifically, in the case that the lithium battery is in a charging state, the calibrated remaining power is

[0080]

[0081] Wherein, CC0 is the remaining power at t1, CC AH is the charge power from t to t1, CC0+CC AH is the current remaining power.

[0082] In actual application, in the case that the single discharge power exceeds the current estimated total available capacity FCC of the battery pack, the single discharge power is allowed to be greater than the total available capacity FCC, and can be discharged to DC AH ≥ FCC+Q REV , and DC AH is continuously calculated, and the current remaining power RC AH is set to 0, and the SOC is set to 0. In the case that DC AH≥ FCC + Q REV , the integral discharge process ends. When the current BMS system starts charging, the current remaining capacity CC AH = FCC - DC AH At this time, if DC AH < 0, the SOC shows 0 when charging starts. And continue to charge until CC AH > Q REV , the SOC exits the 0 value, and as the charging continues, the SOC value starts to increase. The above process can make the actual discharge capacity exceed the total available capacity, that is, the user can be reminded in time to charge, and the rated mileage can be increased, further ensuring that the user's experience is good.

[0083] In another embodiment of the application, as shown in Figure 2 , the above lithium battery includes a battery pack, and the battery pack includes a plurality of single batteries. In the case that the lithium battery is in a discharge state, the process of determining the discharge factor corresponding to the single discharge capacity includes: in the case that the open circuit voltage value of the single battery is equal to a second open circuit voltage threshold 300, determining whether the ampere-hour integral remaining capacity is greater than the open circuit voltage remaining capacity; in the case that the ampere-hour integral remaining capacity is greater than the open circuit voltage remaining capacity, calculating the difference between the ampere-hour integral remaining capacity and the open circuit voltage remaining capacity to obtain a remaining capacity difference; calculating the ratio of the remaining capacity difference to the open circuit voltage remaining capacity to obtain a first adjustment coefficient, and calculating the product of the current discharge factor and the first adjustment coefficient to obtain an adjusted discharge factor. In this embodiment, when the ampere-hour integral remaining capacity is greater than the open circuit voltage remaining capacity, it indicates that the ampere-hour integral method is calculated slower than the open circuit voltage method. Therefore, the current discharge factor F can be adjusted at this time so that the discharge process can be accelerated next time until the remaining capacities calculated by the open circuit voltage method and the ampere-hour integral method are the same.

[0084] Specifically, the ampere-hour integral remaining capacity value is the remaining capacity of the lithium battery calculated by the ampere-hour integral method, and the open circuit voltage remaining capacity is the remaining capacity of the lithium battery calculated by the open circuit voltage method.

[0085] In actual application, as shown in Figure 2 , when the open circuit voltage value of the single battery is equal to the second open circuit voltage threshold 300, that is, V minOCVofCELL = V cent2ofCELL , the current remaining capacity is calculated by the ampere-hour integral method to obtain the ampere-hour integral remaining capacity RC AH = FCC pack - DC AH . If RC AH < RC OCV, it indicates that the ampere-hour integral method first reaches the second open-circuit voltage threshold 300 (V cent2ofCELL ), in which case the ampere-hour integral method can continue to run until the open-circuit voltage is 0. If RC AH > RC OCV , it indicates that the ampere-hour integral method is calculated slower than the open-circuit voltage method, so at this time the current discharge factor F can be adjusted, so

[0086]

[0087]

[0088] In order to further ensure that the subsequent calibrated residual capacity is relatively accurate, in another embodiment of the application, as shown in Figure 2 , the above lithium battery includes a battery pack, and the above battery pack includes a plurality of single batteries. In the case that the above lithium battery is in a discharged state, the process of determining the discharge factor corresponding to the single discharge capacity includes: in the case that the open-circuit voltage value of the single battery is equal to the third open-circuit voltage threshold 200, determining whether the ampere-hour integral residual capacity is greater than the open-circuit residual voltage capacity; in the case that the ampere-hour integral residual capacity is greater than the open-circuit residual voltage capacity, calculating the sum of the current discharge factor and the acceleration factor to obtain the adjusted discharge factor. In this embodiment, when the ampere-hour integral residual capacity is greater than the open-circuit residual voltage capacity, it indicates that the open-circuit voltage method judges that the lithium battery will be empty. At this time, an acceleration factor can be temporarily added in the ampere-hour integral method to prevent the BMS system from causing a system safety failure due to entering an under-voltage protection before the SOC value changes to 0.

[0089] In actual application, as shown in Figure 2 , in the case that the open-circuit voltage value of the single battery is equal to the third open-circuit voltage threshold 200, that is, V minOCVofCELL = V cent3ofCELL , an acceleration factor is added in the discharge factor, so the single discharge capacity can be expressed as , wherein F is the discharge factor, and F L is the acceleration factor. Of course, after DC AH ≥ FCC, the acceleration factor F L can be set to 0.

[0090] In order to further ensure that the calibrated residual capacity is relatively accurate, in another embodiment of the application, the above lithium battery includes a battery pack, and the process of determining the self-consumption capacity includes: using to obtain the self-consumption capacity, wherein DC self is the self-consumption capacity, I self = I Ssysself + I battself , ISsysself is an estimated value of the self-air discharge of the battery pack, battself is an estimated value of the self-loop loss current of the battery pack.

[0091] In actual application,

[0092] In an embodiment of the present application, the current SOC value is corrected by using the calibrated remaining capacity, including: when the calibrated remaining capacity reaches the total available capacity, the SOC value is updated to 100%.

[0093] In a specific embodiment of the present application, the calculation method of the SOC value can be RC AH is the remaining capacity calculated by the ampere-hour integration method, FCC pack is the actual total available capacity.

[0094] The embodiment of the present application further provides a micro control unit. It should be noted that the micro control unit of the embodiment of the present application can be used to execute the calibration method for the SOC provided by the embodiment of the present application. The micro control unit provided by the embodiment of the present application is introduced as follows.

[0095] Figure 4 is a structural schematic diagram of the micro control unit according to the embodiment of the present application. As Figure 4 shown, the micro control unit includes:

[0096] The first calibration unit 10 is configured to calibrate the total available capacity of the lithium battery by using a preset factor to obtain a calibrated total capacity, and calibrate the current SOC value by using the calibrated total capacity, wherein the preset factor includes at least one of the following: the current SOC value, the number of charging times, the dynamic reserved capacity, and the temperature.

[0097] The second calibration unit 20 is configured to calibrate the remaining capacity of the lithium battery by using a preset condition to obtain a calibrated remaining capacity, and calibrate the current SOC value by using the calibrated remaining capacity, wherein the preset condition includes at least one of the following: a fullness judgment condition and a discharge factor, the fullness judgment condition is used to represent whether the remaining capacity reaches a full remaining capacity, and the full remaining capacity is the sum of the total available capacity and the dynamic reserved capacity.

[0098] The first calibration unit is configured to calibrate the total available capacity of the lithium battery by using the current SOC value, the number of charging times, the dynamic reserved capacity or the temperature to obtain a calibrated total capacity, and then correct the current SOC value by using the calibrated total capacity. The second calibration unit is configured to calibrate the residual capacity of the lithium battery by using the full residual condition or the discharge factor to obtain a calibrated residual capacity, and then calibrate the current SOC value by using the calibrated residual capacity. In the micro control unit, the influence of the current SOC value, the number of charging times, the dynamic reserved capacity or the temperature on the total available capacity of the lithium battery is considered to calibrate the total available capacity to obtain the calibrated total capacity, and the influence of whether the current residual capacity reaches the full residual capacity or the discharge factor on the residual capacity of the lithium battery is considered to calibrate the residual capacity. In this way, the obtained SOC value of the lithium battery is more accurate, the situation of sudden change of the SOC value during the operation of the vehicle is avoided, the stability of the battery management system is ensured, and the user experience is good, thereby solving the problem that it is difficult to accurately estimate the SOC value in the prior art.

[0099] In actual application, in some special scenarios, for example, after the lithium battery is initially put into use after leaving the factory, the following method can be used to calculate the SOC value. Specifically, the discharge temperature and discharge current are determined after the battery pack is fully charged, and the discharge capacity is the same each time. After standing for a predetermined time, the data is recorded. Repeat the above process and change the discharge current from 1A to 8A and the discharge temperature from -5°C to 65°C. Among them, every 1A is a gear, and every 10°C is a gear. The cell internal resistance is calculated. The BMS (Battery Management System, BMS for short) calculates the open circuit voltage V OCV

[0100] V OCV =f(V CELL ,T CELL ,I CELL ,DCIR OCV ),

[0101] Among them, V CELL is the voltage of a single battery in the battery pack, T CELL is the discharge temperature of the single battery, I CELL is the discharge current of the single battery, and DCIR OCV is the internal resistance of the single battery. Specifically, the determination method of V CELL is

[0102] V CELL =VCELLpack -I CELL ×R0,

[0103] Among them, V CELLpack R0 represents the actual voltage of a single battery cell collected by the BMS system, and R0 represents the resistance between series nodes within the battery pack. Specifically, DCIR... OCV The method for determining is as follows

[0104] DCIR OCV =f(V CELL ,I CELL ,T CELL ).

[0105] Then, based on the above open-circuit voltage V OCV and discharge temperature T CELL Calculate the remaining RC power OCVcell Then there is

[0106] RC OCVcell =f(V OCV ,T CELL ).

[0107] Then, based on the current estimated total available power (FCC) and using the open-circuit voltage method, the SOC value is calculated, specifically as follows:

[0108]

[0109] Where Npal is the number of individual cells connected in parallel in the battery pack, and RC OCVcell-i Let be the remaining charge of the i-th individual cell.

[0110] In practical applications, after multiple discharges and charges, the total usable capacity of a lithium battery changes. For example, as the lithium battery is used, its total usable capacity decreases, becoming less than the initial usable capacity. Therefore, to ensure a more accurate total usable capacity and further guarantee an accurate SOC value, one embodiment of this application, such as... Figure 2As shown, the lithium battery includes a battery pack, which includes multiple individual cells. The first calibration unit includes a first calculation module, a second calculation module, and a first calibration module. The first calculation module is used to calculate the product of the open-circuit SOC value (i.e., the current SOC value of the lithium battery) and the total available capacity when the lithium battery is in a discharge state and meets preset discharge conditions, to obtain the current remaining capacity. It also calculates the sum of the single discharge capacity of the battery pack and the current remaining capacity to obtain the preset total capacity. The open-circuit SOC value is calculated using the open-circuit voltage method, and the single discharge capacity is... The preset discharge conditions, calculated using the ampere-hour integration method, include: the battery pack being fully charged, the current remaining charge being greater than or equal to the total available charge, the current discharge current being within a preset discharge current range, the current discharge temperature being within a preset discharge temperature range, and the open-circuit voltage of the individual cells being equal to a first open-circuit voltage threshold. The second calculation module is used to calculate the difference between the preset total charge and the total available charge to obtain a target difference. The first calibration module is used to calibrate the total available charge based on the target difference and the target difference range to obtain the calibrated total charge.

[0111] In another embodiment of this application, the target difference range includes an upper limit and a lower limit. The first calibration module includes a first update submodule, a second update submodule, and a third update submodule. The first update submodule is used to update the available total power to the sum of the preset total power and the upper limit of the target difference when the target difference is greater than or equal to the upper limit of the target difference, thus obtaining the calibrated total power. The second update submodule is used to update the available total power to the difference between the preset total power and the lower limit of the target difference when the target difference is less than or equal to the lower limit of the target difference, thus obtaining the calibrated total power. The third update submodule is used to update the available total power to the preset total power when the target difference is within the target difference range, thus obtaining the calibrated total power. This ensures that the available total power can be calibrated relatively simply, and the subsequent calibration of the SOC value using the calibrated total power further ensures that the obtained SOC value is relatively accurate.

[0112] In one specific embodiment of this application, the aforementioned preset total power FCC LEARN ==DC AH +SOC OCV ×FCC, where DC AH To obtain the single discharge quantity using the ampere-hour integration method, SOC OCV The open-circuit SOC value is calculated using the open-circuit voltage method, which is also the current SOC value. FCC represents the total available energy. Then, the target difference is calculated as FCC.LEARN -FCC. In the FCC LEARN -FCC≥FCC LEARN-thresholdmax In the case of calibrating total power consumption, FCC 校准 =FCC LEARN +FCC LEARN-thresholdmax In the FCC LEARN -FCC≤FCC LEARN-thresholdmin In the case of calibrating total power consumption, FCC 校准 =FCC LEARN -FCC LEARN-thresholdmin Among them, FCC LEARN-thresholdmax The upper limit of the target difference, FCC LEARN-thresholdmin This is the lower limit of the target difference. (In the FCC) LEARN -FCC is in [FCC LEARN-thresholdmin FCC LEARN-thresholdmax In the case of […], the FCC 校准 =FCC LEARN This ensures that the total calibration power obtained is neither less than nor greater than the total available power, thus guaranteeing that the total calibration power obtained is relatively accurate.

[0113] In practical applications, the above-mentioned preset discharge conditions can also be the standard discharge mode, specifically, as follows: Figure 2 As shown, the current state of charge (Currsaturated) of the above battery pack is fully charged (i.e., Mainsaturated), CC AH ≥FCC (Current remaining battery power is greater than or equal to total available battery power), I minqualified ≤I PACK ≤I maxqualified (The current discharge current is within the preset discharge current range), T minqualified ≤T PACK ≤T maxqualified (The current discharge temperature is within the preset discharge temperature range) and V minOCVofCELL =V cent1ofCELL (The open-circuit voltage of a single cell is equal to the first open-circuit voltage threshold of 100).

[0114] Specifically, during the calibration of the total available power, if the FCC value of the total available power decreases, the SOH (State of Health) value is immediately updated, indicating that the battery's health status is gradually declining.

[0115] In yet another embodiment of the present application, the first calibration unit comprises a first determining module, a third calculating module and a fourth calculating module. The first determining module is configured to determine the total charging times of the lithium battery and a variation threshold, wherein the variation threshold is the variation threshold of the total available capacity of the lithium battery in each charging. The third calculating module is configured to calculate the product of the total charging times and the variation threshold to obtain a target variation threshold. The fourth calculating module is configured to calculate the difference between the current total available capacity and the target variation threshold to obtain the calibration total capacity. In actual application, as the charging times increase, the total available capacity of the lithium battery gradually decreases. Therefore, in this embodiment, the total charging times is used to calibrate the total available capacity, so as to ensure that the calibration total capacity is more accurate.

[0116] Specifically, since the variation threshold of the lithium battery of different manufacturers is different, the size of the variation threshold is not limited in the present application, and can be flexibly adjusted according to the situation of the lithium battery.

[0117] In a specific embodiment of the present application, the total charging times Timer dc is a function of the total available capacity FCC, so the target variation threshold can be Timer dc × FCC, so that the calibration total capacity FCC 校准 = FCC PRE -Timer dc × FCC, FCC PRE is the current total available capacity, and FCC PRE > Timer dc × FCC.

[0118] In actual application, in order to ensure that the lithium battery still maintains a certain amount of capacity after the SOC is 0, so that the BMS system can work normally, further ensure the stability of the BMS system, and the normal work of other circuits, in another embodiment of the present application, the first calibration unit comprises a fifth calculating module, a sixth calculating module and a seventh calculating module. The fifth calculating module is configured to calculate the product of a first predetermined value and the total charging times to obtain a first target value, and calculate the product of a second predetermined value and the minimum discharge temperature to obtain a second target value. The sixth calculating module is configured to calculate the sum of the dynamic reserved capacity initial value, the first target value and the second target value to obtain the dynamic reserved capacity. The seventh calculating module is configured to calculate the difference between the total available capacity and the dynamic reserved capacity to obtain the calibration total capacity.

[0119] Specifically, through experiments, it is known that the dynamic reserved capacity Q REV is a bivariate linear function of the total charging times and the discharge temperature, so QREV =f(Timer) dc ,T min )=Q0+a×Timer dc +b×T min Where a is the first predetermined value, and Timer dc Let T be the total number of charging cycles, b be the second predetermined value, and T be the total number of charging cycles. min The minimum discharge temperature is given by Q0, which is the initial reserve capacity of the lithium battery at the factory. a and b can be set according to the actual application during calibration testing before the lithium battery leaves the factory. Therefore, the total calibrated capacity (FCC) is given. 校准 =FCC-Q REV .

[0120] In one embodiment of this application, the first calibration unit further includes a second determining module and a first updating module. The second determining module is used to determine the low-temperature compensation charge when the ambient temperature of the lithium battery is currently lower than a preset temperature value. The first updating module is used to update the total available charge using the difference between the actual available charge of the lithium battery and the low-temperature compensation charge, thus obtaining the calibrated total charge. This embodiment considers the impact of low temperature on the total available charge of the lithium battery, ensuring that the obtained calibrated total charge is relatively accurate, further ensuring the accuracy of the subsequently obtained SOC value.

[0121] In one specific embodiment of this application, the FCC 校准 =FCC pack -f(T<T LOWTemp ), of which FCC pack For the actual total available electricity, f(T < T) LOWTemp The low-temperature compensation function is used to determine the low-temperature compensation charge. Furthermore, in the above embodiment, the preset temperature value can be 5°C. Of course, the preset temperature value is not limited to 5°C and can be other temperatures; the specific value can be adjusted according to the actual situation of the lithium battery.

[0122] Specifically, in this application, the discharge capacity of lithium batteries at different discharge temperatures and different currents is tested, and the minimum value is taken as the calculated value. The theoretically usable maximum capacity is then calculated using the difference method, resulting in the following... Figure 3 The relationship between discharge temperature and discharge capacity is shown.

[0123] In actual application process, in order to protect lithium battery, the charger is usually disconnected to stop charging when the battery pack is full. In this case, if the current remaining power is less than the total available power, it will cause the lithium battery to be unable to be fully charged, that is, the SOC value of the lithium battery is forced to be set to 100%, and in the subsequent discharging process of the lithium battery, a sudden change will occur. If the current remaining power has reached the total available power, but has not reached the preset full condition, the SOC value will be greater than 100%. The above two cases will bring bad user experience to the user. Therefore, in order to avoid the above situation of the lithium battery, in another embodiment of the present application, the above lithium battery includes a battery pack, and the second calibration unit includes a third determination module and a fourth determination module. The third determination module is used to determine whether the current charging state reaches the full state and whether the current remaining power reaches the full remaining power based on at least the current charging state, the current remaining power and the full condition when the lithium battery is in the charging state. The full state is determined based on the charging current, the charging voltage of the battery pack and the charging power within the preset time. The fourth determination module is used to determine the full remaining power as the calibration remaining power when the current charging state reaches the full state and the current remaining power reaches the full remaining power.

[0124] In another embodiment of the present application, the third determining module comprises a first determining sub-module and a second determining sub-module. The first determining sub-module is configured to determine whether the current charging state reaches a quasi-full state and whether the current residual capacity reaches a quasi-full residual capacity according to the current charging state, the current residual capacity and a quasi-judgment full condition. The quasi-full residual capacity is a product of the total available capacity and a third target value, and the third target value is less than 1. The quasi-full state is determined based on the charging current, the charging voltage of the battery pack and the charging capacity within a preset time. The quasi-full state and the full state are two different states. The second determining sub-module is configured to determine whether the current charging state reaches the full state and whether the current residual capacity reaches a full residual capacity according to the current charging state, the current residual capacity and the judgment full condition when the current charging state reaches the quasi-full state and the current residual capacity reaches the quasi-full residual capacity. In this embodiment, the current charging state of the lithium battery and the current residual capacity are first determined according to the quasi-judgment full condition. When the current charging state reaches the quasi-full state and the current residual capacity reaches the quasi-full residual capacity, the current charging state and the current residual capacity are further determined according to the judgment full condition. In this way, it can be ensured that the current charging state of the lithium battery and the current residual capacity can be accurately determined, and the sudden change of the SOC value of the lithium battery can be further avoided, and the user experience can be further improved.

[0125] In a specific embodiment of the present application, the third target value can be 0.99, that is, the quasi-full residual capacity can be represented as 0.99xFCC. Of course, in actual application, the third target value is not limited to 0.99, and the third target value can also be other suitable values less than 1.

[0126] In order to further ensure that the current charge state of the lithium battery reaches the quasi-saturated state and the current remaining capacity reaches the quasi-full remaining capacity, in another embodiment of the present application, the micro control unit further comprises a first control unit, a second control unit and a third control unit, wherein the first control unit is configured to, after determining whether the current charge state reaches the quasi-full state and the current remaining capacity reaches the quasi-full remaining capacity according to at least the current charge state, the current remaining capacity and the quasi-full condition, control the lithium battery to continue charging and calculate the current remaining capacity by using the ampere-hour integration method until the current charge state reaches the quasi-full state and the current remaining capacity reaches the quasi-full remaining capacity, in the case that the current charge state does not reach the quasi-full state and the current remaining capacity is less than the quasi-full remaining capacity; the second control unit is configured to control the lithium battery to continue charging until the current charge state reaches the quasi-full state, in the case that the current charge state does not reach the quasi-full state and the current remaining capacity is equal to the quasi-full remaining capacity; and the third control unit is configured to control the lithium battery to continue charging and calculate the current remaining capacity by using the ampere-hour integration method until the current remaining capacity reaches the quasi-full remaining capacity, in the case that the current charge state reaches the quasi-full state and the current remaining capacity is less than the quasi-full remaining capacity.

[0127] In actual application, in the case that the current charge state (Currsaturated) does not reach the quasi-full state (Subsaturated) and the current remaining capacity is less than the quasi-full remaining capacity (CC AH <0.99×FCC), the lithium battery is controlled to continue charging and the current remaining capacity is calculated, i.e. until the current charge state (Currsaturated) reaches the quasi-full state (Subsaturated) and the current remaining capacity reaches the quasi-full remaining capacity (CC AH =0.99×FCC). In the case that the current charge state (Currsaturated) does not reach the quasi-full state (Subsaturated) and the current remaining capacity is equal to the quasi-full remaining capacity (CC AH =0.99×FCC), the lithium battery is controlled to continue charging until the charge state (Currsaturated) reaches the quasi-full state (Subsaturated). In the case that the current charge state (Currsaturated) reaches the quasi-full state (Subsaturated) and the current remaining capacity is less than the quasi-full remaining capacity (CC AHIn the case that the current state of charge (Currsaturated) does not reach the full state (Main saturated) and the current remaining capacity (CC until the current state of charge (Currsaturated) reaches the full state (Main saturated) and the current remaining capacity (CC AH = 0.99 x FCC).

[0128] In an embodiment of the present application, the micro control unit further comprises a fourth control module configured to, after determining that the current state of charge reaches the full state and the current remaining capacity reaches the full remaining capacity, control the lithium battery to continue charging in the case that the current state of charge does not reach the full state and the current remaining capacity is less than or equal to the full remaining capacity, until the state of charge reaches the full state and the remaining capacity reaches the full remaining capacity. In this embodiment, the remaining capacity of the lithium battery is controlled to reach the full remaining capacity, so that the lithium battery has a dynamic reserved capacity, and the lithium battery can still be used for a shorter period of time when the battery capacity is low, i.e. the SOC value is low, and the lithium battery will not suddenly power off, which can ensure a good user experience.

[0129] In actual application, in the case that the current state of charge (Currsaturated) does not reach the full state (Main saturated) and the current remaining capacity (CC AH ≤ FCC + Q REV , the lithium battery is controlled to continue charging and the current remaining capacity is calculated, i.e. until the current state of charge (Currsaturated) reaches the full state (Main saturated) and the current remaining capacity (CC AH = FCC + Q REV .

[0130] Specifically, when the current remaining capacity (CC AH reaches FCC + Q REV , the SOC value is set to 100%, i.e. after the SOC value is 100%, even if the lithium battery continues to charge, the SOC value will not continue to increase. When the BMS system starts discharging, CC AH = FCC.

[0131] Specifically, when the current remaining capacity (CC AH>FCC, the SOC value will be greater than 100%, the actual application process does not allow the above situation, so the amplitude limiting processing, so the SOC value is set to 100%, and no longer change. After the lithium battery begins to discharge, the current remaining power CC AH =FCC, the BMS system begins to discharge counting. That is, the lithium battery will be stored in more dynamic reserve power, the subsequent in the lithium battery remaining power is less, for example, the SOC value is less than 5%, the lithium battery can work for a long time, and will not be quickly powered off, further guarantee the user's experience is good.

[0132] In order to further ensure that the obtained calibrated remaining power is more accurate, in another embodiment of the application, the second calibration unit comprises an eighth calculation module and a ninth calculation module, wherein the eighth calculation module is configured to calculate the difference between the actual total available power, the single discharge power and the self-consumption power to obtain the calibrated remaining power when the lithium battery is in a discharge state or a static state, and the single discharge power is determined based on at least the discharge factor; and the ninth calculation module is configured to calculate the difference between the current remaining power and the self-consumption power to obtain the calibrated remaining power when the lithium battery is in a charging state.

[0133] Specifically, when the lithium battery is in a discharge state or a static state, the calibrated remaining power is calculated as follows:

[0134]

[0135] Wherein, RC AH is the calibrated remaining power, FCC pack is the actual total available power, DC AH is the single discharge power, DC self is the self-consumption power, F is the discharge factor, I pack is the actual discharge current, I self is the self-consumption current.

[0136] Specifically, when the lithium battery is in a charging state, the calibrated remaining power is calculated as follows:

[0137]

[0138] Wherein, CC0 is the remaining power at t1, CC AH is the charge power from t to t1, CC0+CC AH is the current remaining power.

[0139] In the actual application process, when the single discharge capacity exceeds the current estimated total available capacity FCC of the battery pack, the single discharge capacity is allowed to be greater than the total available capacity FCC, and can be discharged to DC AH ≥ FCC + Q REV , and the current remaining capacity RC AH is continuously calculated as DC AH = FCC - DC AH ≥ FCC + Q REV , and the integral discharge process ends. When the current BMS system starts charging, the current remaining capacity CC AH = FCC - DC AH , at this time if DC AH < 0, the SOC shows 0 when charging starts. And continue to charge until CC AH > Q REV , the SOC exits the 0 value, and as the charging continues, the SOC value starts to increase. The above process can make the actual discharge capacity exceed the total available capacity, that is, the user can be reminded in time to charge, and the rated mileage can be increased, further ensuring that the user has a good experience.

[0140] In another embodiment of the application, as shown in Figure 2 , the above lithium battery includes a battery pack, the battery pack includes a plurality of single batteries, and the eighth calculation module includes a third determination submodule, a first calculation submodule and a second calculation submodule. The third determination submodule is configured to determine whether the ampere-hour integral remaining capacity is greater than the open circuit voltage remaining capacity when the open circuit voltage value of the single battery is equal to the second open circuit voltage threshold 300. The first calculation submodule is configured to calculate the difference between the ampere-hour integral remaining capacity and the open circuit voltage remaining capacity to obtain a remaining capacity difference when the ampere-hour integral remaining capacity is greater than the open circuit voltage remaining capacity. The second calculation submodule is configured to calculate the ratio of the remaining capacity difference to the open circuit voltage remaining capacity to obtain a first adjustment coefficient, and calculate the product of the current discharge factor and the first adjustment coefficient to obtain an adjusted discharge factor. In this embodiment, when the ampere-hour integral remaining capacity is greater than the open circuit voltage remaining capacity, it indicates that the ampere-hour integral method is slower than the open circuit voltage method, so the current discharge factor F can be adjusted at this time to accelerate the discharge in the next discharge process until the remaining capacities calculated by the open circuit voltage method and the ampere-hour integral method are the same.

[0141] Specifically, the ampere-hour integral remaining capacity value is the remaining capacity of the lithium battery calculated by the ampere-hour integral method, and the open circuit voltage remaining capacity is the remaining capacity of the lithium battery calculated by the open circuit voltage method.

[0142] In the actual application process, as shown inFigure 2 As shown, when the open-circuit voltage of a single cell is equal to the second open-circuit voltage threshold of 300, i.e., V minOCVofCELL =V cent2ofCELL The remaining energy is calculated using the ampere-hour integral method, and the remaining energy RC is obtained by ampere-hour integral. AH =FCC pack -DC AH If RC AH <RC OCV This indicates that the ampere-hour integration method first reaches the second open-circuit voltage threshold of 300 (V). cent2ofCELL In this case, the ampere-hour integration method can continue to run until the open-circuit voltage is 0. If RC AH >RC OCV This indicates that the ampere-hour integration method is slower than the open-circuit voltage method. Therefore, the current discharge factor F can be adjusted at this point, resulting in:

[0143]

[0144]

[0145] To further ensure the accuracy of the remaining battery power obtained after calibration, in another embodiment of this application, such as... Figure 2 As shown, the lithium battery includes a battery pack, which in turn includes multiple individual cells. The eighth calculation module further includes a fourth determination submodule and a third calculation submodule. The fourth determination submodule is used to determine whether the remaining ampere-hour integrated capacity is greater than the remaining open-circuit voltage capacity when the open-circuit voltage of the individual cell is equal to a third open-circuit voltage threshold of 200. The third calculation submodule is used to calculate the sum of the current discharge factor and acceleration factor when the remaining ampere-hour integrated capacity is greater than the remaining open-circuit voltage capacity, thus obtaining the adjusted discharge factor. In this embodiment, when the remaining ampere-hour integrated capacity is greater than the remaining open-circuit voltage capacity, it indicates that the open-circuit voltage method determines the lithium battery is about to be discharged. At this time, an acceleration factor can be temporarily added to the ampere-hour integrated method to prevent the BMS system from entering undervoltage protection before the SOC value changes to 0, thus preventing a system safety failure.

[0146] In practical applications, such as Figure 2 As shown, when the open-circuit voltage of a single cell is equal to the third open-circuit voltage threshold, i.e., V minOCVofCELL =V cent3ofCELL By adding an acceleration factor to the discharge factor, the amount of electricity discharged in a single cycle can be expressed as: Where F is the discharge factor, F L As an acceleration factor. Of course, in DC AH After reaching ≥FCC, the acceleration factor F can be increased. L Set to 0.

[0147] To further ensure accurate calibration of remaining battery power, in another embodiment of this application, the lithium battery includes a battery pack, and the eighth or ninth calculation module includes a fourth calculation submodule for employing... The above-mentioned self-consumption power is obtained, where DC self For the aforementioned self-consumption of electricity, I self =I Ssysself +I battself I Ssysself I is an estimated value for the air discharge of the aforementioned battery pack itself. battself This is an estimated value for the current loss in the circuit of the aforementioned battery pack.

[0148] In practical applications,

[0149] In one embodiment of this application, the second calibration unit includes a second update module, which is used to update the SOC value to 100% when the remaining calibration power reaches the total available power.

[0150] In one specific embodiment of this application, the SOC value can be calculated as follows: Among them, RC AH The remaining electricity is calculated using the ampere-hour integration method, FCC pack This represents the actual total available power.

[0151] The aforementioned microcontroller unit includes a processor and a memory. The first calibration unit and the second calibration unit are stored in the memory as program units, and the processor executes the program units stored in the memory to achieve the corresponding functions.

[0152] The processor contains a core, which retrieves the corresponding program units from memory. One or more cores can be configured, and adjusting core parameters can address the difficulty in accurately estimating SOC values ​​in existing technologies.

[0153] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0154] This invention provides a computer-readable storage medium storing a program that, when executed by a processor, implements the aforementioned SOC calibration method.

[0155] This invention provides a processor for running a program, wherein the program executes the calibration method of the SOC.

[0156] In a typical embodiment of the present application, a battery management system is also provided, which comprises a micro control unit and a lithium battery, and the micro control unit is configured to execute any of the above SOC calibration methods.

[0157] The battery management system comprises a micro control unit and a lithium battery, and the micro control unit is configured to execute any of the above SOC calibration methods. In the calibration method, the total available capacity of the lithium battery is calibrated by using the current SOC value, the number of charges, the dynamic reserved capacity or the temperature to obtain a calibrated total capacity, and the current SOC value is corrected by using the calibrated total capacity. The remaining capacity of the lithium battery is calibrated by using the full remaining capacity condition or the discharge factor to obtain a calibrated remaining capacity, and the current SOC value is calibrated by using the calibrated remaining capacity. In the calibration method, the influence of the current SOC value, the number of charges, the dynamic reserved capacity or the temperature on the total available capacity of the lithium battery is considered to calibrate the total available capacity to obtain the calibrated total capacity, and the influence of whether the current remaining capacity reaches the full remaining capacity or the discharge factor on the remaining capacity of the lithium battery is considered to calibrate the remaining capacity. This ensures that the obtained SOC value of the lithium battery is relatively accurate, avoids the situation that the SOC value suddenly changes during the operation of the vehicle, ensures the stability of the battery management system, and ensures that the user has a good use experience, thereby solving the problem that it is difficult to accurately estimate the SOC value in the prior art.

[0158] An apparatus is provided, and the apparatus includes a processor, a memory, and a program stored on the memory and executable on the processor. When the processor executes the program, at least the following steps are implemented:

[0159] In step S101, the total available capacity of the lithium battery is calibrated by using a preset factor to obtain a calibrated total capacity, and the current SOC value is calibrated by using the calibrated total capacity. The preset factor includes at least one of the following: the current SOC value, the number of charges, the dynamic reserved capacity, and the temperature.

[0160] In step S102, the remaining capacity of the lithium battery is calibrated by using a preset condition to obtain a calibrated remaining capacity, and the current SOC value is calibrated by using the calibrated remaining capacity. The preset condition includes at least one of the following: the full remaining capacity condition and the discharge factor. The full remaining capacity condition is used to represent whether the remaining capacity reaches the full remaining capacity, and the full remaining capacity is the sum of the total available capacity and the dynamic reserved capacity.

[0161] The apparatus in this document can be a server, a PC, a PAD, a mobile phone, etc.

[0162] The application also provides a computer program product, which is suitable for executing a program including at least the following method steps when executed on a data processing device:

[0163] In step S101, the total available power of the lithium battery is calibrated by using a preset factor to obtain a calibrated total power, and the current SOC value is calibrated by using the calibrated total power, wherein the preset factor includes at least one of the current SOC value, the number of charging times, the dynamic reserved power and the temperature.

[0164] In step S102, the residual power of the lithium battery is calibrated by using a preset condition to obtain a calibrated residual power, and the current SOC value is calibrated by using the calibrated residual power, wherein the preset condition includes at least one of a full-charge condition and a discharge factor, the full-charge condition is used to represent whether the residual power reaches a full-charge residual power, and the full-charge residual power is the sum of the total available power and the dynamic reserved power.

[0165] In the above embodiments of the application, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0166] In several embodiments provided in the present application, it should be understood that the disclosed technical contents can be implemented by other ways. Among them, the above-described device embodiments are only schematic, for example, the division of the above units can be a logical function division, and actual implementation can have another division way, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed units can be indirect coupling or communication connection through some interfaces, units or modules, which can be electrical or other forms.

[0167] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place or distributed on multiple units. Part or all of the units can be selected to achieve the purpose of the embodiment scheme according to actual needs.

[0168] In addition, each functional unit in each embodiment of the application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0169] The integrated unit described above, if realized in the form of a software function unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on such understanding, the technical solutions of the present application, essentially or in other words, the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a number of instructions to make a computer device (which can be a personal computer, a server or a network device, etc.) execute all or part of the steps of the above-mentioned method of various embodiments of the present application. The aforementioned storage medium includes: a U disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a mobile hard disk, a magnetic disk or an optical disk, and various media that can store program codes.

[0170] From the above description, it can be seen that the above-mentioned embodiments of the present application realize the following technical effects:

[0171] 1) In the calibration method of the SOC of the present application, the current SOC value, the number of charges, the dynamic reserved capacity or the temperature is used to calibrate the total available capacity of the lithium battery, to obtain a calibrated total capacity, and then the calibrated total capacity is used to correct the current SOC value. The remaining capacity of the lithium battery is calibrated by using the full condition or the discharge factor, to obtain a calibrated remaining capacity, and then the calibrated remaining capacity is used to calibrate the current SOC value. In the calibration method of the present application, the influence of the current SOC value, the number of charges, the dynamic reserved capacity or the temperature on the total available capacity of the lithium battery is considered to calibrate the total available capacity and obtain the calibrated total capacity; and the influence of whether the current remaining capacity reaches the full remaining capacity or the discharge factor on the remaining capacity of the lithium battery is considered to calibrate the remaining capacity. This ensures that the obtained SOC value of the lithium battery is relatively accurate, avoids the situation that the SOC value suddenly changes during vehicle operation, ensures the stability of the battery management system, and ensures that the user's use experience is good, thereby solving the problem that it is difficult to accurately estimate the SOC value in the prior art.

[0172] 2) In the micro control unit of the application, the first calibration unit is used to calibrate the total available capacity of the lithium battery by using the current SOC value, the number of charging times, the dynamic reserved capacity or the temperature, to obtain the calibrated total capacity, and then correct the current SOC value by using the calibrated total capacity. The second calibration unit is used to calibrate the remaining capacity of the lithium battery by using the full remaining capacity condition or the discharge factor, to obtain the calibrated remaining capacity, and then calibrate the current SOC value by using the calibrated remaining capacity. In the micro control unit of the application, the influence of the current SOC value, the number of charging times, the dynamic reserved capacity or the temperature on the total available capacity of the lithium battery is considered to calibrate the total available capacity to obtain the calibrated total capacity, and the influence of the current remaining capacity reaching the full remaining capacity or the discharge factor on the remaining capacity of the lithium battery is considered to calibrate the remaining capacity. In this way, the obtained SOC value of the lithium battery is relatively accurate, the situation of sudden change of the SOC value during the running of the vehicle is avoided, the stability of the battery management system is ensured, and the user's use experience is good, thereby solving the problem that it is difficult to accurately estimate the SOC value in the prior art.

[0173] 3) The battery management system of the application comprises a micro control unit and a lithium battery, and the micro control unit is used to execute any one of the above-mentioned SOC calibration methods. In the calibration method, the total available capacity of the lithium battery is calibrated by using the current SOC value, the number of charging times, the dynamic reserved capacity or the temperature to obtain the calibrated total capacity, and then the current SOC value is corrected by using the calibrated total capacity. The remaining capacity of the lithium battery is calibrated by using the full remaining capacity condition or the discharge factor to obtain the calibrated remaining capacity, and then the current SOC value is calibrated by using the calibrated remaining capacity. In the calibration method of the application, the influence of the current SOC value, the number of charging times, the dynamic reserved capacity or the temperature on the total available capacity of the lithium battery is considered to calibrate the total available capacity to obtain the calibrated total capacity, and the influence of the current remaining capacity reaching the full remaining capacity or the discharge factor on the remaining capacity of the lithium battery is considered to calibrate the remaining capacity. In this way, the obtained SOC value of the lithium battery is relatively accurate, the situation of sudden change of the SOC value during the running of the vehicle is avoided, the stability of the battery management system is ensured, and the user's use experience is good, thereby solving the problem that it is difficult to accurately estimate the SOC value in the prior art.

[0174] The above only describes the preferred embodiments of the application and is not intended to limit the application. Those skilled in the art can make various changes and modifications to the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A calibration method of a SOC, characterized by, The calibration method comprises: The total available capacity of the lithium battery is calibrated by using a preset factor to obtain a calibrated total capacity, and the current SOC value is calibrated by using the calibrated total capacity; The remaining capacity of the lithium battery is calibrated by using a preset condition to obtain a calibrated remaining capacity, and the current SOC value is calibrated by using the calibrated remaining capacity, the preset condition comprising at least one of a fullness judging condition and a discharge factor, the fullness judging condition being used to represent whether the remaining capacity reaches a full remaining capacity, the full remaining capacity being a sum of the total available capacity and a dynamic reserved capacity, In a case where the preset factor comprises a charging number, the total available capacity of the lithium battery is calibrated by using a preset factor to obtain a calibrated total capacity, comprising: determining a total charging number of the lithium battery and a change threshold, the change threshold being a change threshold of the total available capacity when the lithium battery is charged each time; calculating a product of the total charging number and the change threshold to obtain a target change threshold; calculating a difference between the current total available capacity and the target change threshold to obtain the calibrated total capacity; Or, In a case where the preset factor comprises a dynamic reserved capacity, the total available capacity of the lithium battery is calibrated by using a preset factor to obtain a calibrated total capacity, comprising: calculating a product of a first predetermined value and a total charging number to obtain a first target value, and calculating a product of a second predetermined value and a minimum discharge temperature to obtain a second target value; calculating a sum of a dynamic reserved capacity initial value, the first target value and the second target value to obtain the dynamic reserved capacity; calculating a difference between the total available capacity and the dynamic reserved capacity to obtain the calibrated total capacity.

2. The calibration method of claim 1, wherein, The lithium battery comprises a battery pack, the battery pack comprising a plurality of single batteries, in a case where the preset factor comprises the current SOC value, the total available capacity of the lithium battery is calibrated by using a preset factor to obtain a calibrated total capacity, comprising: In a case where the lithium battery is in a discharging state and a preset discharging condition is met, a product of an open-circuit SOC value and the total available capacity is calculated to obtain the current remaining capacity, and a sum of a single discharging capacity of the battery pack and the current remaining capacity is calculated to obtain a preset total capacity, the open-circuit SOC value being calculated by using an open-circuit voltage method, the single discharging capacity being calculated by using an ampere-hour integration method, the preset discharging condition comprising that the battery pack is in a full state, the current remaining capacity is greater than or equal to the total available capacity, a current discharging current is within a preset discharging current range, a current discharging temperature is within a preset discharging temperature range, and an open-circuit voltage value of the single battery is equal to a first open-circuit voltage threshold value; A difference between the preset total capacity and the total available capacity is calculated to obtain a target difference value; The total available capacity is calibrated according to the target difference value and a target difference value range to obtain the calibrated total capacity.

3. The method of calibration of claim 2, wherein, The target difference range includes a target difference upper limit and a target difference lower limit, and the available total capacity is calibrated according to the target difference and the target difference range to obtain the calibrated total capacity, including: In a case where the target difference is greater than or equal to the target difference upper limit, the available total capacity is updated as a sum of the preset total capacity and the target difference upper limit to obtain the calibrated total capacity; In a case where the target difference is less than or equal to the target difference lower limit, the available total capacity is updated as a difference between the preset total capacity and the target difference lower limit to obtain the calibrated total capacity; In a case where the target difference is within the target difference range, the available total capacity is updated as the preset total capacity to obtain the calibrated total capacity.

4. The method of calibration of claim 1, wherein, In a case where the preset factor includes temperature, the available total capacity of the lithium battery is calibrated by using the preset factor to obtain the calibrated total capacity, including: In a case where the current ambient temperature of the lithium battery is lower than a preset temperature value, a low-temperature compensation capacity is determined; The available total capacity is updated by using a difference between the current actual available total capacity of the lithium battery and the low-temperature compensation capacity to obtain the calibrated total capacity.

5. The method of calibration of claim 1, wherein, The lithium battery includes a battery pack, and the remaining capacity of the lithium battery is calibrated by using a preset condition to obtain the calibrated remaining capacity, including: In a case where the lithium battery is in a charging state, whether the current charging state reaches a full state and whether the current remaining capacity reaches a full remaining capacity are determined according to at least the current charging state, the current remaining capacity and a fullness determination condition, the full state being determined based on a charging current, a charging voltage of the battery pack and a charging capacity within a preset time; In a case where the current charging state reaches the full state and the current remaining capacity reaches the full remaining capacity, the full remaining capacity is determined as the calibrated remaining capacity.

6. The method of calibration of claim 5, wherein, In a case where the lithium battery is in a charging state, whether the current charging state reaches a full state and whether the current remaining capacity reaches a full remaining capacity are determined according to at least the current charging state, the current remaining capacity and a fullness determination condition, including: Whether the current charging state reaches a quasi-full state and whether the current remaining capacity reaches a quasi-full remaining capacity are determined according to at least the current charging state, the current remaining capacity and a quasi-fullness determination condition, the quasi-full remaining capacity being a product of the available total capacity and a third target value, the third target value being less than 1, the quasi-full state being determined based on a charging current, a charging voltage of the battery pack and a charging capacity within a preset time, the quasi-full state and the full state being two different states; In a case where the current charging state reaches the quasi-full state and the current remaining capacity reaches the quasi-full remaining capacity, whether the current charging state reaches the full state and whether the current remaining capacity reaches the full remaining capacity are further determined according to at least the current charging state, the current remaining capacity and the fullness determination condition.

7. The method of calibration of claim 6, wherein, After determining, based at least on the current charging state, the current remaining battery level, and the quasi-fullness condition, whether the current charging state has reached a quasi-fully charged state and whether the current remaining battery level has reached a quasi-fully charged remaining battery level, the calibration method further includes: If the current charging state has not reached the near-fully charged state and the current remaining power is less than the near-fully charged remaining power, the lithium battery is controlled to continue charging and the ampere-hour integration method is used to continue calculating the current remaining power until the current charging state reaches the near-fully charged state and the current remaining power reaches the near-fully charged remaining power. If the current charging state has not reached the near-fully charged state and the current remaining power is equal to the near-fully charged remaining power, the lithium battery is controlled to continue charging until the current charging state reaches the near-fully charged state. When the current charging state reaches the near-fully charged state and the current remaining power is less than the near-fully charged remaining power, the lithium battery is controlled to continue charging and the remaining power is calculated using the ampere-hour integration method until the remaining power reaches the near-fully charged remaining power.

8. The method of calibration of claim 6, wherein, After determining, based at least on the current charging state, the current remaining battery level, and the saturation condition, whether the current charging state has reached the fully charged state and whether the current remaining battery level has reached the fully charged remaining battery level, the calibration method further includes: If the current charging state has not reached the fully charged state and the current remaining power is less than or equal to the fully charged remaining power, the lithium battery is controlled to continue charging until the charging state reaches the fully charged state and the remaining power reaches the fully charged remaining power.

9. The calibration method according to any one of claims 1 to 8, characterized in that, The remaining capacity of the lithium battery is calibrated using preset conditions to obtain the calibrated remaining capacity, including: When the lithium battery is in a discharging state or a stationary state, the difference between the actual total available capacity, the capacity of a single discharge, and the capacity consumed by the battery itself is calculated to obtain the calibrated remaining capacity. The capacity of a single discharge is determined at least based on the discharge factor. When the lithium battery is in a charging state, the difference between the current remaining power and the power consumed by the battery is calculated to obtain the calibrated remaining power.

10. The method of calibration of claim 9, wherein, The lithium battery includes a battery pack, which includes multiple individual cells. When the lithium battery is in a discharging state, the process of determining the discharge factor corresponding to the single discharge capacity includes: If the open-circuit voltage of the single cell is equal to the second open-circuit voltage threshold, determine whether the remaining charge value of the ampere-hour integration is greater than the remaining charge value of the open-circuit voltage. If the remaining charge after ampere-hour integration is greater than the remaining charge after open-circuit voltage, the difference between the remaining charge after ampere-hour integration and the remaining charge after open-circuit voltage is calculated to obtain the remaining charge difference. Calculate the ratio of the remaining power difference to the remaining power at the open circuit voltage to obtain a first adjustment coefficient, and then calculate the product of the current discharge factor and the first adjustment coefficient to obtain the adjusted discharge factor.

11. The method of calibration of claim 9, wherein, The lithium battery comprises a battery pack including a plurality of single batteries, and in a case where the lithium battery is in a discharging state, the process of determining the discharge factor corresponding to the single discharging electric quantity comprises: in a case where the open circuit voltage value of the single battery is equal to a third open circuit voltage threshold value, determining whether the ampere-hour integral residual electric quantity value is greater than an open circuit residual voltage electric quantity; in a case where the ampere-hour integral residual electric quantity is greater than the open circuit residual voltage electric quantity, calculating a sum of the current discharge factor and an acceleration factor to obtain an adjusted discharge factor.

12. The method of calibrating of claim 9, wherein, The lithium battery comprises a battery pack, and the process of determining the self-consumption electric quantity comprises: Adopting , obtaining the self-consumed electric quantity, wherein, is the self-consumed electric quantity, , is the estimated value of the self-air discharge of the battery pack, is the estimated value of the self-loop loss current of the battery pack.

13. The method of calibrating of claim 1, wherein, The SOC value is corrected by using the calibrated residual electric quantity, comprising: in a case where the calibrated residual electric quantity reaches the total available electric quantity, updating the SOC value to 100%.

14. A micro control unit, characterized by The micro control unit comprises: a first calibration unit configured to calibrate the total available electric quantity of the lithium battery by using a preset factor to obtain a calibrated total electric quantity, and to calibrate the current SOC value by using the calibrated total electric quantity; a second calibration unit configured to calibrate the residual electric quantity of the lithium battery by using a preset condition to obtain a calibrated residual electric quantity, and to calibrate the current SOC value by using the calibrated residual electric quantity, the preset condition comprising at least one of a fullness judgment condition and a discharge factor, the fullness judgment condition being used to represent whether the residual electric quantity reaches a full residual electric quantity, the full residual electric quantity being a sum of the total available electric quantity and a dynamic reserved electric quantity, wherein, in a case where the preset factor comprises a charging number, the first calibration unit comprises a first determination module, a third calculation module and a fourth calculation module, wherein the first determination module is configured to determine a total charging number of the lithium battery and a change threshold value, the change threshold value being a change threshold value of the total available electric quantity when the lithium battery is charged each time; the third calculation module is configured to calculate a product of the total charging number and the change threshold value to obtain a target change threshold value; and the fourth calculation module is configured to calculate a difference between the current total available electric quantity and the target change threshold value to obtain the calibrated total electric quantity; or, in a case where the preset factor comprises a dynamic reserved electric quantity, the first calibration unit comprises a fifth calculation module, a sixth calculation module and a seventh calculation module, the fifth calculation module is configured to calculate a product of a first predetermined value and a total charging number to obtain a first target value, and to calculate a product of a second predetermined value and a minimum discharging temperature to obtain a second target value; the sixth calculation module is configured to calculate a sum of a dynamic reserved electric quantity initial value, the first target value and the second target value to obtain the dynamic reserved electric quantity; and the seventh calculation module is configured to calculate a difference between the total available electric quantity and the dynamic reserved electric quantity to obtain the calibrated total electric quantity.

15. A computer-readable storage medium, characterized in that, The computer readable storage medium comprises a stored program, wherein the program executes the calibration method of the SOC according to any one of claims 1 to 13.

16. A processor, comprising: The processor is configured to run a program, wherein the program executes the calibration method of the SOC according to any one of claims 1 to 13 when running.

17. A battery management system, characterized by, Comprising: a micro control unit for performing the calibration method of the SOC according to any one of claims 1 to 13 and a lithium battery.

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