A SOC correction method, system and device for the end of discharge of a battery system

Abstract

The present invention discloses a method, a system and a device for correcting the SOC at the end of the discharge of a battery system. The method is applied to an energy storage device, which includes a battery system and a battery management system, and the battery system includes battery cells; the method is executed by the battery management system and includes obtaining the historical discharge current value of the battery cells; determining the discharge rate of the battery system according to the historical discharge current value; obtaining the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system; calculating the true value of the SOC of the battery system according to the temperature information of the battery system, the historical minimum voltage value and the discharge rate of the battery system; and correcting the displayed value of the SOC of the battery system according to the true value of the SOC of the battery system. The technical solution provided by the embodiments of the present invention can solve the problem that the existing battery management system is not accurate enough in SOC correction.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management systems, and particularly to a method, system and device for correcting the state of charge (SOC) at the end of battery system discharge. Background Art

[0002] With the development of new energy vehicles, electric vehicles have gradually become the main means of transportation for people's daily travel. The power of electric vehicles mainly comes from the battery system, and the power performance of the battery system directly affects the performance of the whole vehicle.

[0003] The existing battery management systems have the problem of inaccurate SOC correction. At the end of the battery system discharge, if the calculated SOC value by the battery management system has a large deviation, the maximum performance of the battery cannot be exerted, and the user experience is not good. Therefore, it is particularly important to correct the SOC deviation at the end of battery discharge. Summary of the Invention

[0004] The present invention provides a method, system and device for correcting the SOC at the end of battery system discharge to solve the problem of inaccurate SOC correction in the existing battery management systems.

[0005] According to one aspect of the present invention, there is provided a method for correcting the SOC at the end of battery system discharge, which is applied to an energy storage device. The energy storage device includes a battery system and a battery management system, and the battery system includes battery cells. The method is executed by the battery management system and includes:

[0006] Obtaining the historical discharge current value of the battery cells;

[0007] Determining the discharge rate of the battery system according to the historical discharge current value;

[0008] Obtaining the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system;

[0009] Calculating the true SOC value of the battery system according to the temperature information of the battery system, the historical minimum voltage value and the discharge rate of the battery system;

[0010] Correcting the displayed SOC value of the battery system according to the true SOC value of the battery system.

[0011] Further, the obtaining the historical discharge current value of the battery cells includes:

[0012] Dividing a preset time period into a plurality of sampling intervals;

[0013] Obtaining the historical discharge current value of each battery cell of the battery system within each sampling interval.

[0014] Further, determining the discharge rate of the battery system according to the historical discharge current value includes:

[0015] Taking the average value of the historical discharge current values of each battery cell in the battery system within each sampling interval to generate a historical average discharge current value;

[0016] Calculating the discharge rate of the battery system according to the historical average discharge current value and the available capacity of the battery system.

[0017] Further, obtaining the temperature information of the battery system and the historical minimum voltage value of the battery cells in the battery system includes:

[0018] Obtaining the current temperature information of the battery cells in the battery system;

[0019] Obtaining the historical minimum voltage value of each battery cell in the battery system within each sampling interval.

[0020] Further, calculating the true SOC value of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system includes:

[0021] Taking the average value of the historical minimum voltage values of each battery cell in the battery system within each sampling interval to generate a historical average minimum voltage value;

[0022] According to the current temperature information of the battery cells in the battery system, looking up a table to obtain the first preset temperature value and the second preset temperature value closest to the current temperature information of the battery cells; wherein, the current temperature information of the battery cells is between the first preset temperature value and the second preset temperature value;

[0023] According to the discharge rate of the battery system, looking up a table to obtain the first preset discharge rate and the second preset discharge rate closest to the discharge rate; wherein, the discharge rate of the battery system is between the first preset discharge rate and the second preset discharge rate;

[0024] Based on the temperature-voltage-discharge rate curve, determining the first SOC value of the battery system according to the first preset temperature value, the first preset discharge rate, and the second preset discharge rate;

[0025] Based on the temperature-voltage-discharge rate curve, determining the second SOC value of the battery system according to the second preset temperature value, the first preset discharge rate, and the second preset discharge rate;

[0026] Calculating the true SOC value of the battery system by interpolation according to the first SOC value and the second SOC value.

[0027] Further, based on the temperature-voltage-discharge rate curve, determining the first SOC value of the battery system according to the first preset temperature value, the first preset discharge rate, and the second preset discharge rate includes:

[0028] Based on the temperature-voltage-discharge rate curve, obtain, by looking up a table, the first preset SOC value of the battery system corresponding to the first preset discharge rate and the second preset SOC value of the battery system corresponding to the second preset discharge rate at the first preset temperature value;

[0029] Calculate the first SOC value of the battery system according to the first preset SOC value and the second preset SOC value;

[0030] The first SOC value of the battery system is calculated by the following formula:

[0031]

[0032] where SOC1 is the first SOC value of the battery system, SOC 11 is the first preset SOC value of the battery system, SOC 12 is the second preset SOC value of the battery system, A is the discharge rate of the battery system, A1 is the first preset discharge rate, and A2 is the second preset discharge rate.

[0033] Further, based on the temperature-voltage-discharge rate curve, determining the second SOC value of the battery system according to the second preset temperature value, the first preset discharge rate, and the second preset discharge rate includes:

[0034] Based on the temperature-voltage-discharge rate curve, obtain, by looking up a table, the third preset SOC value of the battery system corresponding to the first preset discharge rate and the fourth preset SOC value of the battery system corresponding to the second preset discharge rate at the second preset temperature value;

[0035] Calculate the second SOC value of the battery system according to the third preset SOC value and the fourth preset SOC value;

[0036] The second SOC value of the battery system is calculated by the following formula:

[0037]

[0038] where SOC2 is the second SOC value of the battery system, SOC 21 is the third preset SOC value of the battery system, and the SOC 22is the fourth preset SOC value of the battery system, A is the discharge rate of the battery system, A1 is the first preset discharge rate, and A2 is the second preset discharge rate.

[0039] Further, based on the first SOC value and the second SOC value, the true SOC value of the battery system is calculated by interpolation, and the calculation is performed through the following formula:

[0040]

[0041] Among them, SOC 真实 is the true SOC value of the battery system, T is the current temperature information of the battery cells of the battery system, T1 is the first preset temperature value, T2 is the second preset temperature value, SOC1 is the first SOC value of the battery system, and SOC2 is the second SOC value of the battery system.

[0042] Further, based on the true SOC value of the battery system, the SOC display value of the battery system is corrected, including:

[0043] Obtain the current SOC display value of the battery system;

[0044] Compare the current SOC display value of the battery system with the true SOC value of the battery system to generate a comparison result;

[0045] According to the comparison result, adjust the correction parameter of the SOC display value to match the SOC display value at the next moment with the true SOC value of the battery system;

[0046] Among them, the SOC display value at the next moment is calculated through the following formula:

[0047]

[0048] Among them, SOC 下一时刻 is the SOC display value at the next moment, SOC 当前 is the current SOC display value of the battery system, M is the correction parameter, K is the life state coefficient of the battery system, T is the current temperature information of the battery cells of the battery system, Q T is the capacity of the battery system at temperature T, and I is the historical discharge current value of the battery cell.

[0049] In a second aspect, an embodiment of the present invention provides a battery management system, including:

[0050] An acquisition module for acquiring the historical discharge current value of the battery cell;

[0051] A calculation unit for determining the discharge rate of the battery system according to the historical discharge current value;

[0052] The acquisition module is further configured to acquire the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system;

[0053] The calculation unit is further configured to calculate the true SOC value of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system;

[0054] A correction module for correcting the SOC display value of the battery system according to the true SOC value of the battery system.

[0055] In a third aspect, an embodiment of the present invention provides an energy storage device, including: a battery system and the battery management system described in the second aspect, where the battery system includes battery cells; the battery management system is used to execute the SOC correction method at the end of the discharge of the battery system.

[0056] The technical solution of the embodiment of the present invention obtains the historical discharge current value of the battery cells; determines the discharge rate of the battery system according to the historical discharge current value; obtains the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system; calculates the true SOC value of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system; corrects the SOC display value of the battery system according to the true SOC value of the battery system. The SOC correction method at the end of the discharge of the battery system provided by the embodiment of the present invention calculates the true SOC value of the battery system by obtaining the temperature information, the historical minimum voltage value, and the discharge rate of the battery system, realizes more accurate calculation of the true SOC value of the battery system, and corrects the SOC display value of the battery system by the true SOC value of the battery system, solving the problem that the existing battery management system corrects the SOC inaccurately.

[0057] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. Description of the Drawings

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0059] Figure 1 It is a flowchart of a SOC correction method at the end of battery system discharge provided by an embodiment of the present invention;

[0060] Figure 2 It is a flowchart of another SOC correction method at the end of battery system discharge provided by an embodiment of the present invention;

[0061] Figure 3 It is a flowchart of yet another SOC correction method at the end of battery system discharge provided by an embodiment of the present invention;

[0062] Figure 4 It is a flowchart of yet another SOC correction method at the end of battery system discharge provided by an embodiment of the present invention;

[0063] Figure 5 It is a flowchart of yet another SOC correction method at the end of battery system discharge provided by an embodiment of the present invention;

[0064] Figure 6 It is a temperature-voltage-discharge rate curve graph provided by an embodiment of the present invention;

[0065] Figure 7 It is a flowchart of yet another SOC correction method at the end of battery system discharge provided by an embodiment of the present invention;

[0066] Figure 8 It is a flowchart of yet another SOC correction method at the end of battery system discharge provided by an embodiment of the present invention;

[0067] Figure 9 It is a flowchart of yet another SOC correction method at the end of battery system discharge provided by an embodiment of the present invention;

[0068] Figure 10 It is a schematic structural diagram of a battery management system provided by an embodiment of the present invention;

[0069] Figure 11 It is a schematic structural diagram of an energy storage device provided by an embodiment of the present invention. Detailed implementation manners

[0070] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0071] It should be noted that the terms "first", "second", etc. in the specification, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0072] Figure 1 is a flowchart of a method for correcting the SOC at the end of battery system discharge provided by an embodiment of the present invention. Refer to Figure 1 , the method for correcting the SOC at the end of battery system discharge provided by an embodiment of the present invention is applied to an energy storage device. The energy storage device includes a battery system and a battery management system, and the battery system includes battery cells; the method is executed by the battery management system and includes:

[0073] S101. Obtain the historical discharge current value of the battery cell.

[0074] Specifically, there may be multiple battery cells in the battery system, and the battery cells can be connected in series or in parallel. The historical discharge current value refers to the discharge current values of the battery cells at different sampling times within a certain period of the past.

[0075] S102. Determine the discharge rate of the battery system according to the historical discharge current value.

[0076] Specifically, the discharge rate of the battery system is a measure of the discharge speed, which refers to the current intensity required for the battery system to discharge its rated capacity within a certain period of time. Calculate the discharge rate of the battery system according to the historical discharge current value.

[0077] S103. Obtain the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system.

[0078] Specifically, temperature has a great influence on the discharge function of the battery system. When the temperature changes, parameters such as the power of the battery system will also change accordingly. Obtaining the temperature information of the battery system can calculate the true value of the SOC (State Of Charge) of the battery system more accurately. The historical minimum voltage value refers to the minimum voltage value of each battery cell within each sampling interval within a certain period of the past.

[0079] S104. Calculate the true SOC value of the battery system based on the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system.

[0080] Specifically, the SOC value refers to the ratio of the remaining capacity of the battery system after being used for a period of time or left unused for a long time to the capacity in the fully charged state. The true SOC value of the battery system can be calculated based on the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system.

[0081] S105. Correct the SOC display value of the battery system according to the true SOC value of the battery system.

[0082] Specifically, at the end of the discharge of the battery system, if the SOC display value calculated by the battery management system is higher than the actual SOC value, the change rate of the SOC display value is accelerated to correct the SOC display value; if the SOC display value calculated by the battery management system is lower than the actual SOC value, the change rate of the SOC display value is slowed down to correct the SOC display value. Ensure that there is no large error between the SOC display value and the actual SOC value of the battery system.

[0083] The SOC correction method at the end of the discharge of the battery system provided in this embodiment determines the discharge rate of the battery system by obtaining the historical discharge current value of the battery cell, obtains the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system, and calculates the true SOC value of the battery system. And according to the true SOC value of the battery system, the SOC display value of the battery system is corrected. The technical solution provided in this embodiment realizes the calculation of the true SOC value of the battery system, and corrects the SOC display value of the battery system through the true SOC value of the battery system. Such a setting solves the problem that the existing battery management system corrects the SOC inaccurately, gives full play to the battery performance, and improves the user experience.

[0084] Optionally, Figure 2 is a flowchart of another SOC correction method at the end of the discharge of the battery system provided by the embodiment of the present invention. On the basis of the above embodiment, refer to Figure 2 , the SOC correction method at the end of the discharge of the battery system provided in this embodiment includes:

[0085] S201. Divide a preset time period into multiple sampling intervals.

[0086] Specifically, the preset time period can be any historical time period during which the battery system operates. For example, it can be a historical time period adjacent to the current moment, such as the previous 30s, 60s, 90s, etc. of the current moment. Dividing the preset time into multiple sampling intervals facilitates the collection of multiple groups of data.

[0087] S202. Obtain the historical discharge current values of each battery cell of the battery system within each sampling interval.

[0088] Specifically, since the battery system continuously operates within the preset time period, the magnitudes of the historical discharge current values of each battery cell of the battery system within each sampling interval are not all the same.

[0089] S102. Determine the discharge rate of the battery system according to the historical discharge current values.

[0090] S103. Obtain the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system.

[0091] S104. Calculate the true SOC value of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system.

[0092] S105. Correct the SOC display value of the battery system according to the true SOC value of the battery system.

[0093] Optionally, Figure 3 is another flowchart of the SOC correction method at the end of the battery system discharge provided by the embodiment of the present invention. On the basis of the above embodiment, refer to Figure 3 , the SOC correction method at the end of the battery system discharge provided by this embodiment includes:

[0094] S101. Obtain the historical discharge current value of the battery cell.

[0095] S301. Take the average value of the historical discharge current values of each battery cell of the battery system within each sampling interval to generate a historical average discharge current value.

[0096] Specifically, the historical average discharge current value can be calculated by the following formula:

[0097]

[0098] where I 平均 is the historical average discharge current value of the battery cell, I is the historical discharge current value of the battery cell, t is the preset time period, is the sum of the currents within the preset time period. The ratio of the sum of the currents within the preset time period to the preset time period is the historical average discharge current value.

[0099] S302. Calculate the discharge rate of the battery system according to the historical average discharge current value and the available capacity of the battery system.

[0100] Specifically, the discharge rate of the battery system can be calculated by the following formula:

[0101]

[0102] Among them, A is the discharge rate of the battery system, K is the battery life state coefficient, Q T is the available capacity of the battery at temperature T. The discharge rate of the battery system can be obtained by dividing the historical average discharge current value by the product of the battery life state coefficient and the available capacity of the battery at temperature T.

[0103] S103. Obtain the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system.

[0104] S104. Calculate the true value of the SOC of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system.

[0105] S105. Correct the displayed value of the SOC of the battery system according to the true value of the SOC of the battery system.

[0106] Optionally, Figure 4 is a flowchart of another method for correcting the SOC at the end of the discharge of the battery system provided by the embodiment of the present invention. On the basis of the above embodiment, refer to Figure 4 , the method for correcting the SOC at the end of the discharge of the battery system provided by this embodiment includes:

[0107] S101. Obtain the historical discharge current value of the battery cell.

[0108] S102. Determine the discharge rate of the battery system according to the historical discharge current value.

[0109] S401. Obtain the current temperature information of the battery cells in the battery system.

[0110] Specifically, the current temperature information of the battery cells in the battery system reflects the current working state of the battery system, and the temperature change will cause changes in various battery parameters.

[0111] S402. Obtain the historical minimum voltage value of each battery cell in the battery system at each sampling interval.

[0112] Specifically, since the battery system continuously operates within a preset time period, the historical minimum voltage value of each battery cell in the battery system changes at each sampling interval. The historical minimum voltage value is the minimum voltage value among the voltage values of each battery cell in the battery system at each sampling interval.

[0113] S104. Calculate the true value of the SOC of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system.

[0114] S105. Correct the SOC display value of the battery system according to the true SOC value of the battery system.

[0115] Optionally, Figure 5 FIG. is another flowchart of the SOC correction method at the end of the discharge of the battery system provided by the embodiment of the present invention. On the basis of the above embodiment, refer to Figure 5 , the SOC correction method at the end of the discharge of the battery system provided in this embodiment includes:

[0116] S101. Obtain the historical discharge current value of the battery cell.

[0117] S102. Determine the discharge rate of the battery system according to the historical discharge current value.

[0118] S103. Obtain the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system.

[0119] S501. Take the average value of the historical minimum voltage values of the battery cells of the battery system in each sampling interval to generate a historical average minimum voltage value.

[0120] Specifically, the historical average minimum voltage value can be calculated by the following formula:

[0121]

[0122] where V 平均 is the historical average minimum voltage value, is the sum of the minimum voltages within a preset time period. It can be understood that the ratio of the sum of the minimum voltages within a preset time period to the preset time period is the historical average minimum voltage value.

[0123] S502. According to the current temperature information of the battery cells of the battery system, look up a table to obtain the first preset temperature value and the second preset temperature value closest to the current temperature information of the battery cells.

[0124] Specifically, the battery management system can pre-store a temperature table of the battery cells. After looking up the table to obtain the first preset temperature value and the second preset temperature value closest to the current temperature information of the battery cells of the battery system, by means of interpolation, determine the first preset temperature value and the second preset temperature value that make the magnitude of the current temperature information of the battery cells of the battery system fall between the first preset temperature value and the second preset temperature value. Exemplarily, the temperature table of the battery cells can include multiple preset temperature values, such as 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, etc. If the current temperature of the battery cells of the battery system is 25°C, then set the first preset temperature value to 20°C and the second preset temperature value to 30°C.

[0125] S503. Obtain the first preset discharge rate and the second preset discharge rate closest to the discharge rate of the battery system by looking up a table according to the discharge rate of the battery system.

[0126] Specifically, the battery management system can pre-store a discharge rate table of the battery cell. After obtaining the first preset discharge rate and the second preset discharge rate closest to the discharge rate of the battery system by looking up the table, the first preset discharge rate and the second preset discharge rate that make the magnitude of the discharge rate of the battery system fall between the first preset discharge rate and the second preset discharge rate are determined by interpolation.

[0127] S504. Based on the temperature-voltage-discharge rate curve, determine the first SOC value of the battery system according to the first preset temperature value, the first preset discharge rate, and the second preset discharge rate.

[0128] Specifically, the temperature-voltage-discharge rate curve is used to represent the relationship between voltage and SOC value at a certain temperature and discharge rate. Exemplarily, Figure 6 is a temperature-voltage-discharge rate curve diagram provided by an embodiment of the present invention. Refer to Figure 6 . When the temperature remains unchanged, the horizontal axis represents voltage, the vertical axis represents the SOC value corresponding to the voltage, and each curve corresponds to the relationship between voltage and SOC value at a certain discharge rate. When the first preset temperature value, the first preset discharge rate, and the second preset discharge rate are determined, the corresponding SOC value can be obtained according to the voltage.

[0129] S505. Based on the temperature-voltage-discharge rate curve, determine the second SOC value of the battery system according to the second preset temperature value, the first preset discharge rate, and the second preset discharge rate.

[0130] Specifically, when the temperature changes, the temperature-voltage-discharge rate curve will also change accordingly. When the second preset temperature value, the first preset discharge rate, and the second preset discharge rate are determined, the corresponding SOC value can be obtained according to the voltage.

[0131] S506. Calculate the true SOC value of the battery system by interpolation according to the first SOC value and the second SOC value.

[0132] Specifically, the true SOC value refers to the actual SOC value of the current battery system. The true SOC value of the battery system calculated by interpolation is between the first SOC value and the second SOC value.

[0133] S105. Correct the SOC display value of the battery system according to the true SOC value of the battery system.

[0134] Optionally,Figure 7 This is another flowchart of the SOC correction method at the end of battery system discharge provided by an embodiment of the present invention. Based on the above embodiment, refer to Figure 7 , the SOC correction method at the end of battery system discharge provided by this embodiment includes:

[0135] S101. Obtain the historical discharge current value of the battery cell.

[0136] S102. Determine the discharge rate of the battery system according to the historical discharge current value.

[0137] S103. Obtain the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system.

[0138] S501. Take the average value of the historical minimum voltage values of the battery cells of the battery system in each sampling interval to generate a historical average minimum voltage value.

[0139] S502. According to the current temperature information of the battery cells of the battery system, look up a table to obtain the first preset temperature value and the second preset temperature value that are closest to the current temperature information of the battery cells.

[0140] S503. According to the discharge rate of the battery system, look up a table to obtain the first preset discharge rate and the second preset discharge rate that are closest to the discharge rate.

[0141] S601. Based on the temperature-voltage-discharge rate curve, look up a table to obtain the first preset SOC value of the battery system corresponding to the first preset discharge rate and the second preset SOC value of the battery system corresponding to the second preset discharge rate at the first preset temperature value.

[0142] Specifically, Table 1 shows the SOC values corresponding to different discharge rates at the first preset temperature. When the historical minimum voltage value of the battery cells of the battery system is determined, the first preset SOC value of the battery system corresponding to the first preset discharge rate can be obtained as SOC 11 , and the second preset SOC value of the battery system corresponding to the second preset discharge rate is SOC 21 .

[0143] Table 1 is the SOC values corresponding to different discharge rates at the first preset temperature.

[0144] Serial number Discharge rate A <![CDATA[V 平均 > 1 <![CDATA[A1]]> <![CDATA[SOC 11 > 2 <![CDATA[A2]]> <![CDATA[SOC 12 >

[0145] S602. Calculate the first SOC value of the battery system according to the first preset SOC value and the second preset SOC value.

[0146] The first SOC value of the battery system is calculated by the following formula:

[0147]

[0148] Among them, SOC1 is the first SOC value of the battery system, and SOC 11 is the first preset SOC value of the battery system, and SOC 12 is the second preset SOC value of the battery system, A is the discharge rate of the battery system, A1 is the first preset discharge rate, and A2 is the second preset discharge rate.

[0149] Specifically, it can be known from the calculation formula that the result of dividing the difference between the second preset SOC value and the first preset SOC value of the battery system by the difference between the second preset discharge rate and the first preset discharge rate, multiplying by the difference between the discharge rate of the battery system and the first preset discharge rate, and then adding the first preset SOC value of the battery system can obtain the first SOC value of the battery system. Calculating the SOC value by the interpolation method can ensure that the calculation result is between the first preset SOC value and the second preset SOC value, reducing the calculation error.

[0150] S505. Based on the temperature-voltage-discharge rate curve, determine the second SOC value of the battery system according to the second preset temperature value, the first preset discharge rate, and the second preset discharge rate.

[0151] S506. Calculate the true SOC value of the battery system by interpolation according to the first SOC value and the second SOC value.

[0152] S105. Correct the SOC display value of the battery system according to the true SOC value of the battery system.

[0153] Optionally, Figure 8 is another flowchart of the SOC correction method at the end of the battery system discharge provided by the embodiment of the present invention. On the basis of the above embodiment, refer to Figure 8 , the SOC correction method at the end of the battery system discharge provided by this embodiment includes:

[0154] S101. Obtain the historical discharge current value of the battery cell.

[0155] S102. Determine the discharge rate of the battery system according to the historical discharge current value.

[0156] S103. Obtain the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system.

[0157] S501. Take the average value of the historical minimum voltage values of the battery cells of the battery system in each sampling interval to generate a historical average minimum voltage value.

[0158] S502. Obtain the first preset temperature value and the second preset temperature value closest to the current temperature information of the battery cells of the battery system by looking up a table according to the current temperature information of the battery cells of the battery system.

[0159] S503. Obtain the first preset discharge rate and the second preset discharge rate closest to the discharge rate of the battery system by looking up a table according to the discharge rate of the battery system.

[0160] S504. Based on the temperature-voltage-discharge rate curve, determine the first SOC value of the battery system according to the first preset temperature value, the first preset discharge rate and the second preset discharge rate.

[0161] S701. Based on the temperature-voltage-discharge rate curve, obtain the third preset SOC value of the battery system corresponding to the first preset discharge rate and the fourth preset SOC value of the battery system corresponding to the second preset discharge rate at the second preset temperature by looking up a table.

[0162] Specifically, Table 2 shows the SOC values corresponding to different discharge rates at the second preset temperature. When the historical minimum voltage value of the battery cells of the battery system is determined, the third preset SOC value of the battery system corresponding to the first preset discharge rate can be obtained as SOC 21 , and the fourth preset SOC value of the battery system corresponding to the second preset discharge rate is SOC 22 .

[0163] Table 2 is a table of SOC values corresponding to different discharge rates at the second preset temperature.

[0164] Serial number Discharge rate A <![CDATA[V 平均 > 1 <![CDATA[A1]]> <![CDATA[SOC 21 > 2 <![CDATA[A2]]> <![CDATA[SOC 22 >

[0165] S702. Calculate the second SOC value of the battery system according to the third preset SOC value and the fourth preset SOC value.

[0166] The second SOC value of the battery system is calculated by the following formula:

[0167]

[0168] where SOC2 is the second SOC value of the battery system, SOC 21 is the third preset SOC value of the battery system, and the SOC 22 is the fourth preset SOC value of the battery system, A is the discharge rate of the battery system, A1 is the first preset discharge rate, and A2 is the second preset discharge rate.

[0169] Specifically, it can be known from the calculation formula that the result of dividing the difference between the fourth preset SOC value and the third preset SOC value of the battery system by the difference between the second preset discharge rate and the first preset discharge rate, multiplying the difference between the discharge rate of the battery system and the first preset discharge rate, and then adding the third preset SOC value of the battery system can obtain the second SOC value of the battery system. Calculating the SOC value by interpolation can ensure that the calculation result is between the third preset SOC value and the fourth preset SOC value, reducing the calculation error.

[0170] S506. Calculate the true SOC value of the battery system by interpolation according to the first SOC value and the second SOC value.

[0171] S105. Correct the SOC display value of the battery system according to the true SOC value of the battery system.

[0172] Optionally, calculating the true SOC value of the battery system by interpolation according to the first SOC value and the second SOC value is calculated by the following formula:

[0173]

[0174] where SOC 真实 is the true SOC value of the battery system, T is the current temperature information of the battery cells of the battery system, T1 is the first preset temperature value, T2 is the second preset temperature value, SOC1 is the first SOC value of the battery system, and SOC2 is the second SOC value of the battery system.

[0175] Specifically, it can be known from the calculation formula that the result of dividing the difference between the second SOC value and the first SOC value by the difference between the second preset temperature value and the first preset temperature value, multiplying the current temperature information of the battery cells of the battery system and the first preset temperature value, and then adding the first SOC value can obtain the true SOC value of the battery system. Calculating the SOC value by interpolation can ensure that the calculation result is the true SOC value of the battery system, providing accurate data for the subsequent correction of the SOC of the battery system.

[0176] Optionally, Figure 9 is another flowchart of the SOC correction method at the end of the discharge of the battery system provided by the embodiment of the present invention. On the basis of the above embodiment, see Figure 9 , the SOC correction method at the end of the discharge of the battery system provided by this embodiment includes:

[0177] S101. Obtain the historical discharge current value of the battery cells.

[0178] S102. Determine the discharge rate of the battery system according to the historical discharge current value.

[0179] S103. Obtain the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system.

[0180] S104. Calculate the true value of the SOC of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system.

[0181] S801. Obtain the current SOC display value of the battery system.

[0182] Specifically, the current SOC display value of the battery system is the SOC value calculated by the battery system based on the estimation of the discharge situation. Since the actual discharge situation of the battery system is more complex than the estimated situation, there may be a certain error between the SOC display value and the true SOC value.

[0183] S802. Compare the current SOC display value of the battery system with the true SOC value of the battery system to generate a comparison result.

[0184] Specifically, since there may be an error between the current SOC display value of the battery system and the true SOC value of the battery system, according to the comparison, it can be obtained that the current SOC display value of the battery system is greater than the true SOC value of the battery system, the current SOC display value of the battery system is equal to the true SOC value of the battery system, or the current SOC display value of the battery system is less than the true SOC value of the battery system.

[0185] S803. Adjust the correction parameter of the SOC display value according to the comparison result to match the SOC display value at the next moment with the true SOC value of the battery system.

[0186] Optionally, the SOC display value at the next moment is calculated by the following formula:

[0187]

[0188] where, SOC 下一时刻 is the SOC display value at the next moment, SOC 当前 is the current SOC display value of the battery system, M is the correction parameter, K is the life state coefficient of the battery system, T is the current temperature information of the battery cells of the battery system, Q T is the capacity of the battery system at temperature T, and I is the historical discharge current value of the battery cells.

[0189] Specifically, according to the calculation formula, the next moment's SOC display value can be obtained by subtracting the correction parameter multiplied by the total current of the battery cells of the battery system from the current SOC display value of the battery system and then dividing the result by the product of the battery system's life state coefficient and the capacity of the battery system at temperature T. If the current SOC display value of the battery system is greater than the true SOC value of the battery system, then make M>1 to accelerate the change rate of the SOC display value; if the current SOC display value of the battery system is equal to the true SOC value of the battery system, then make M = 1 to keep the change rate of the SOC display value unchanged; if the current SOC display value of the battery system is less than the true SOC value of the battery system, then make M<1 to slow down the change rate of the SOC display value.

[0190] Optionally, Table 3 is the pulse discharge power table of the battery system. Referring to Table 3, the maximum power that the battery can discharge can be found by corresponding the true SOC value to the pulse discharge power table, so as to ensure that the output power is the maximum power that the battery can truly output.

[0191] Table 3 is the pulse discharge power table of the battery system.

[0192] SOC / T -30℃ -20℃ -10℃ 0℃ 10℃ 20℃ 30℃ 40℃ 50℃ 55℃ 0％ 0 0 0 0 0 0 0 0 0 0 10％ 4 7 12 19 35 52 65 65 49 37 20％ 14 28 31 54 78 81 111 116 92 44 30％ 19 41 49 71 86 90 127 127 101 45 40％ 24 50 59 74 91 95 128 128 102 45 50％ 29 58 68 88 117 124 130 130 103 46 60％ 34 63 81 95 133 133 133 133 105 47 70％ 36 65 84 97 137 137 137 137 108 48 80％ 38 69 86 100 141 141 141 141 112 50 90％ 42 72 89 103 145 145 145 145 115 51 100％ 46 81 94 109 154 154 154 154 122 54

[0193] Optionally, Figure 10 is a schematic structural diagram of a battery management system provided by an embodiment of the present invention. On the basis of the above embodiment, referring to Figure 10 the battery management system 10 provided by the embodiment of the present invention includes:

[0194] An acquisition module 11, configured to acquire the historical discharge current value of the battery cells;

[0195] A calculation unit 12, configured to determine the discharge rate of the battery system according to the historical discharge current value;

[0196] The acquisition module 11 is further configured to acquire the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system;

[0197] The calculation unit 12 is further configured to calculate the true SOC value of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system;

[0198] A correction module 13, configured to correct the SOC display value of the battery system according to the true SOC value of the battery system.

[0199] The battery management system provided by the embodiment of the present invention includes an acquisition module, a calculation unit, and a correction module. After the acquisition module obtains the historical discharge current value of the battery cell, the temperature information of the battery system, and the historical minimum voltage value of the battery cells in the battery system, the calculation unit determines the discharge rate of the battery system according to the historical discharge current value, and calculates the true SOC value of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system. Then, the correction module corrects the SOC display value of the battery system according to the true SOC value of the battery system calculated by the calculation unit. The battery management system provided by this embodiment realizes more accurate calculation of the true SOC value of the battery system, and corrects the SOC display value of the battery system through the true SOC value of the battery system. It solves the problem that the existing battery management system is not accurate enough in SOC correction.

[0200] Optionally, the acquisition module 11 is specifically configured to divide a preset time period into multiple sampling intervals; and acquire the historical discharge current values of the battery cells in the battery system in each sampling interval.

[0201] Optionally, the calculation unit 12 is specifically configured to take the average value of the historical discharge current values of the battery cells in the battery system in each sampling interval to generate a historical average discharge current value; and calculate the discharge rate of the battery system according to the historical average discharge current value and the available capacity of the battery system.

[0202] Optionally, the acquisition module 11 is further configured to acquire the current temperature information of the battery cells in the battery system; and acquire the historical minimum voltage values of the battery cells in the battery system in each sampling interval.

[0203] Optionally, the calculation unit 12 is further configured to average the historical minimum voltage values of the battery cells of the battery system within each sampling interval to generate a historical average minimum voltage value; obtain, by looking up a table, a first preset temperature value and a second preset temperature value that are closest to the current temperature information of the battery cells of the battery system according to the current temperature information of the battery cells of the battery system; wherein, the current temperature information of the battery cells is between the first preset temperature value and the second preset temperature value; obtain, by looking up a table, a first preset discharge rate and a second preset discharge rate that are closest to the discharge rate of the battery system according to the discharge rate of the battery system; wherein, the discharge rate of the battery system is between the first preset discharge rate and the second preset discharge rate; based on the temperature-voltage-discharge rate curve, determine a first SOC value of the battery system according to the first preset temperature value, the first preset discharge rate, and the second preset discharge rate; based on the temperature-voltage-discharge rate curve, determine a second SOC value of the battery system according to the second preset temperature value, the first preset discharge rate, and the second preset discharge rate; and calculate the true SOC value of the battery system by interpolation according to the first SOC value and the second SOC value.

[0204] Optionally, the calculation unit 12 is specifically configured to, based on the temperature-voltage-discharge rate curve, obtain, by looking up a table, a first preset SOC value of the battery system corresponding to the first preset discharge rate and a second preset SOC value of the battery system corresponding to the second preset discharge rate at the first preset temperature value;

[0205] Calculate a first SOC value of the battery system according to the first preset SOC value and the second preset SOC value;

[0206] The first SOC value of the battery system is calculated by the following formula:

[0207]

[0208] Wherein, SOC1 is the first SOC value of the battery system, SOC 11 is the first preset SOC value of the battery system, SOC 12 is the second preset SOC value of the battery system, A is the discharge rate of the battery system, A1 is the first preset discharge rate, and A2 is the second preset discharge rate.

[0209] Optionally, the calculation unit 12 is specifically further configured to, based on the temperature-voltage-discharge rate curve, obtain, by looking up a table, a third preset SOC value of the battery system corresponding to the first preset discharge rate and a fourth preset SOC value of the battery system corresponding to the second preset discharge rate at the second preset temperature value;

[0210] Calculate the second SOC value of the battery system according to the third preset SOC value and the fourth preset SOC value;

[0211] The second SOC value of the battery system is calculated by the following formula:

[0212]

[0213] where SOC2 is the second SOC value of the battery system, SOC 21 is the third preset SOC value of the battery system, and the SOC 22 is the fourth preset SOC value of the battery system, A is the discharge rate of the battery system, A1 is the first preset discharge rate, and A2 is the second preset discharge rate.

[0214] Optionally, the calculation unit 12 is specifically configured to calculate the true SOC value of the battery system by interpolation according to the first SOC value and the second SOC value, and calculate it by the following formula:

[0215]

[0216] where SOC 真实 is the true SOC value of the battery system, T is the current temperature information of the battery cells of the battery system, T1 is the first preset temperature value, and T2 is the second preset temperature value.

[0217] Optionally, the calibration module 13 is specifically configured to obtain the current SOC display value of the battery system;

[0218] Compare the current SOC display value of the battery system with the true SOC value of the battery system to generate a comparison result;

[0219] According to the comparison result, adjust the correction parameter of the SOC display value to match the SOC display value at the next moment with the true SOC value of the battery system;

[0220] where the SOC display value at the next moment is calculated by the following formula:

[0221]

[0222] where SOC 下一时刻 is the SOC display value at the next moment, SOC 当前 is the current SOC display value of the battery system, M is the correction parameter, K is the life state coefficient of the battery system, T is the current temperature information of the battery cells of the battery system, and Q T is the capacity of the battery system at temperature T.

[0223] Optionally, Figure 11 is a schematic structural diagram of an energy storage device provided by an embodiment of the present invention. On the basis of the above embodiment, refer to Figure 11 , the energy storage device 30 provided by the embodiment of the present invention includes the battery management system 10 described in any of the above embodiments. The battery system 20 includes battery cells. The battery management system 10 is used to execute the SOC correction method at the end of the discharge of the battery system 20 described in any of the above embodiments. The energy storage device 30 proposed in this embodiment includes the battery management system 10 in any of the above embodiments and has the beneficial effects of the battery management system 10 in any of the above embodiments, which will not be elaborated here.

[0224] It should be understood that various forms of the processes shown above can be used, steps can be reordered, added, or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, which is not limited herein.

[0225] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for correcting the SOC at the end of battery system discharge, characterized in that, The method is applied to an energy storage device, which includes a battery system and a battery management system. The battery system includes battery cells. The method is executed by the battery management system and includes: Obtain the historical discharge current value of the battery cells; Determine the discharge rate of the battery system according to the historical discharge current value; Obtain the temperature information of the battery system and the historical minimum voltage value of the battery cells in the battery system; Calculate the true SOC value of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system; Correct the displayed SOC value of the battery system according to the true SOC value of the battery system; Among them, the obtaining of the historical discharge current value of the battery cells includes: Divide a preset time period into multiple sampling intervals; Obtain the historical discharge current value of each battery cell in the battery system within each sampling interval; Among them, the determining of the discharge rate of the battery system according to the historical discharge current value includes: Take the average value of the historical discharge current values of each battery cell in the battery system within each sampling interval to generate a historical average discharge current value; Calculate the discharge rate of the battery system according to the historical average discharge current value and the available capacity of the battery system; Among them, the obtaining of the temperature information of the battery system and the historical minimum voltage value of the battery cells in the battery system includes: Obtain the current temperature information of the battery cells in the battery system; Obtain the historical minimum voltage value of each battery cell in the battery system within each sampling interval; Among them, the calculating of the true SOC value of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system includes: According to the current temperature information of the battery cells in the battery system, look up a table to obtain the first preset temperature value and the second preset temperature value that are closest to the current temperature information of the battery cells. Among them, the current temperature information of the battery cells is between the first preset temperature value and the second preset temperature value; According to the discharge rate of the battery system, look up a table to obtain the first preset discharge rate and the second preset discharge rate that are closest to the discharge rate. Among them, the discharge rate of the battery system is between the first preset discharge rate and the second preset discharge rate; Based on the temperature-voltage-discharge rate curve, determine the first SOC value of the battery system according to the first preset temperature value, the first preset discharge rate, and the second preset discharge rate; Based on the temperature-voltage-discharge rate curve, determine the second SOC value of the battery system according to the second preset temperature value, the first preset discharge rate, and the second preset discharge rate; Calculate the true SOC value of the battery system by interpolation according to the first SOC value and the second SOC value.

2. The method according to claim 1, wherein The calculating of the true SOC value of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system includes: The historical minimum voltage values of each battery cell in the battery system within each sampling interval are averaged to generate a historical average minimum voltage value.

3. The method according to claim 1, wherein The determining of the first SOC value of the battery system based on the temperature-voltage-discharge rate curve according to the first preset temperature value, the first preset discharge rate, and the second preset discharge rate includes: Based on the temperature-voltage-discharge rate curve, look up the table to obtain the first preset SOC value of the battery system corresponding to the first preset discharge rate and the second preset SOC value of the battery system corresponding to the second preset discharge rate at the first preset temperature value; Calculate the first SOC value of the battery system according to the first preset SOC value and the second preset SOC value; Wherein, the first SOC value of the battery system is calculated by the following formula: ； Among them, SOC1 is the first SOC value of the battery system, and SOC 11 is the first preset SOC value of the battery system, and SOC 12 is the second preset SOC value of the battery system, A is the discharge rate of the battery system, A1 is the first preset discharge rate, and A2 is the second preset discharge rate.

4. The method according to claim 1, characterized in that, The determining of the second SOC value of the battery system based on the temperature-voltage-discharge rate curve according to the second preset temperature value, the first preset discharge rate, and the second preset discharge rate includes: Based on the temperature-voltage-discharge rate curve, look up the table to obtain the third preset SOC value of the battery system corresponding to the first preset discharge rate and the fourth preset SOC value of the battery system corresponding to the second preset discharge rate at the second preset temperature value; Calculate the second SOC value of the battery system according to the third preset SOC value and the fourth preset SOC value; Wherein, the second SOC value of the battery system is calculated by the following formula: ; wherein, SOC2 is the second SOC value of the battery system, and SOC 21 is the third preset SOC value of the battery system, and the SOC 22 is the fourth preset SOC value of the battery system, A is the discharge rate of the battery system, A1 is the first preset discharge rate, and A2 is the second preset discharge rate.

5. The method according to claim 1, wherein The interpolation calculation of the true SOC value of the battery system according to the first SOC value and the second SOC value is calculated by the following formula: ； where SOC 真实 is the true value of the SOC of the battery system, T is the current temperature information of the battery cells of the battery system, T1 is the first preset temperature value, T2 is the second preset temperature value, SOC1 is the first SOC value of the battery system, and SOC2 is the second SOC value of the battery system.

6. The method according to claim 1, wherein The correction of the SOC display value of the battery system according to the true SOC value of the battery system includes: Obtain the current SOC display value of the battery system; Compare the current SOC display value of the battery system with the true SOC value of the battery system to generate a comparison result; According to the comparison result, adjust the correction parameter of the SOC display value to match the SOC display value at the next moment with the true SOC value of the battery system; Wherein, the SOC display value at the next moment is calculated by the following formula: ; among them, SOC 下一时刻 is the SOC display value at the next moment, SOC 当前 is the current SOC display value of the battery system, M is the correction parameter, K is the life state coefficient of the battery system, T is the current temperature information of the battery cells of the battery system, Q T is the capacity of the battery system at temperature T, and I is the historical discharge current value of the battery cells.

7. A battery management system, characterized in that, Including: An acquisition module for acquiring the historical discharge current value of the battery cell; A calculation unit for determining the discharge rate of the battery system according to the historical discharge current value; The acquisition module is further configured to acquire the temperature information of the battery system and the historical minimum voltage value of the battery cells of the battery system; The calculation unit is further configured to calculate the true SOC value of the battery system according to the temperature information of the battery system, the historical minimum voltage value, and the discharge rate of the battery system; A correction module for correcting the SOC display value of the battery system according to the true SOC value of the battery system; wherein, the acquisition module includes: a sampling interval division unit and an interval discharge current acquisition unit; The sampling interval division unit is configured to divide a preset time period into multiple sampling intervals; The interval discharge current acquisition unit is used to acquire the historical discharge current values of each battery cell of the battery system within each sampling interval; Among them, the calculation unit includes: a historical average discharge current calculation component and a discharge rate calculation component; The historical average discharge current calculation component is used to take the average of the historical discharge current values of each battery cell of the battery system within each sampling interval to generate a historical average discharge current value; The discharge rate calculation component is used to calculate the discharge rate of the battery system according to the historical average discharge current value and the available capacity of the battery system; Among them, the acquisition module further includes: a temperature information acquisition unit and a historical minimum voltage value acquisition unit; The temperature information acquisition unit is used to acquire the current temperature information of the battery cells in the battery system; The historical minimum voltage value acquisition unit is used to acquire the historical minimum voltage values of each battery cell of the battery system within each sampling interval; Among them, the calculation unit further includes: a preset temperature value acquisition component, a preset discharge rate acquisition component, a first SOC determination component, a second SOC value determination component, and an SOC true value determination component; The preset temperature value acquisition component is used to look up a table according to the current temperature information of the battery cells of the battery system to obtain a first preset temperature value and a second preset temperature value that are closest to the current temperature information of the battery cells; wherein, the current temperature information of the battery cells is between the first preset temperature value and the second preset temperature value; The preset discharge rate acquisition component is used to look up a table according to the discharge rate of the battery system to obtain a first preset discharge rate and a second preset discharge rate that are closest to the discharge rate; wherein, the discharge rate of the battery system is between the first preset discharge rate and the second preset discharge rate; The first SOC determination component is used to determine the first SOC value of the battery system based on the temperature-voltage-discharge rate curve according to the first preset temperature value, the first preset discharge rate, and the second preset discharge rate; The second SOC value determination component is used to determine the second SOC value of the battery system based on the temperature-voltage-discharge rate curve according to the second preset temperature value, the first preset discharge rate, and the second preset discharge rate; The SOC true value determination component is used to calculate the true SOC value of the battery system by interpolation according to the first SOC value and the second SOC value.

8. An energy storage device, characterized in that, Including: A battery system and the battery management system according to claim 7, wherein the battery system includes battery cells; the battery management system is used to execute the SOC correction method at the end of discharge of the battery system according to any one of claims 1 to 6.

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