A method and device for correcting the state of charge of an automotive battery system

Abstract

The present invention discloses a method and device for correcting the state of charge of an automotive battery system, which relates to the field of battery technology. According to the correspondence between the linear working range of the voltage-current curve of the battery and the working conditions, this correction method can determine whether the current working condition is suitable for SOC correction, and perform SOC correction only when the voltage-current curve is in the linear working range, reducing the error introduced by the correction and improving the reliability of SOC. At the same time, before executing the SOC correction strategy, it is first determined whether the current working condition corresponds to the linear working range of the voltage-current curve of the battery. Only when the working condition corresponds to the linear working range of the voltage-current curve of the battery, SOC correction is performed, reducing the error introduced by the correction and improving the reliability of SOC. Further, after meeting the SCO correction enabling condition, the difference between the currently measured voltage and the ampere-hour back-calculated voltage is used to determine whether to enable SOC correction, avoiding the frequent jitter of SOC caused by frequent activation of SOC correction.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly relates to a method and device for correcting the state of charge of an automotive battery system. Background Art

[0002] As a core component of new energy vehicles, the power battery system is crucial for the development of new energy vehicles. The battery management system (BMS) is the core component of the power battery system, and the state of charge (SOC) of the power supply system is the core technical parameter of the BMS. As a direct reflection of the battery power, the SOC provides a reference for the driver to estimate the remaining mileage on the one hand, and provides an important basis for battery management and maintenance on the other hand. In addition, the SOC is the basis for other control algorithms of the BMS. Without accurate SOC, no matter how many protection functions are added, the BMS cannot work properly because the battery will often be in a protected state, and the battery life cannot be extended either. Therefore, its accuracy and robustness are extremely important.

[0003] In related technologies, the commonly used SOC correction methods include the open circuit voltage method and the ampere-hour integration method. Among them, the open circuit voltage method uses the corresponding relationship between the open circuit voltage (OCV) and the SOC to obtain the battery SOC in the steady state (also called the static state). The ampere-hour integration method is to measure the current of the battery by using a current sensor during the operation of the battery, perform an integration operation on the charge and discharge current of the battery with respect to time, and then estimate the dynamic SOC value of the battery.

[0004] Since the ampere-hour integration method has high requirements for the current sampling accuracy, otherwise large cumulative errors may occur after long-term operation, a method combining the open circuit voltage method and the ampere-hour integration method is also adopted. After the battery has been running for a long time, the SOC error accumulated by the ampere-hour integration is relatively large, and the open circuit voltage of the battery after it is in the static or pseudo-static state needs to be used to correct the SOC. This correction method is called the pseudo-static correction method, that is, the method of using the pseudo-static state to correct the SOC of the ampere-hour integration method of the battery. Ah The process is mostly to simply determine that when the current (I) of the current high-voltage bus is less than a certain threshold (for example, 10 A) and lasts for a certain period of time (for example, 10 s), it is considered that the current battery is in a pseudo-static state, and then the OCV of the current battery is deduced by using the formula U = OCV ± IR (where OCS represents the open circuit voltage) of the open circuit voltage method, and then the SOC of the open circuit voltage method is obtained according to the OCV-SOC relationship table. OCV Finally, directly correct the SOC Ah to SOC OCV .

[0005] However, the above-mentioned pseudo-static correction method has the following deficiencies: When using the pseudo-static correction SOC under certain working conditions, new errors will be introduced to the SOC, reducing the reliability of the SOC. Summary of the Invention

[0006] It should be noted that one contribution of the present inventor to the prior art is to discover the reason for introducing new errors to the SOC when using the pseudo-static correction SOC under certain working conditions: Since the open-circuit voltage OCV is used to correct the SOC Ah When, it is necessary to convert the measured voltage value U into the open-circuit voltage OCV. According to the conversion formula U = OCV ± IR, the applicable condition for the conversion is based on the linear relationship between U and I. However, under certain working conditions, the voltage-current curve (i.e., the U-I curve) of the battery will show a non-linear relationship (i.e., a non-straight line relationship). When the battery is in this non-linear relationship, using the converted open-circuit voltage OCV to correct the SOC Ah will inevitably introduce new errors and reduce the reliability of the SOC.

[0007] Based on the above discovery, the object of the present invention is to at least solve one of the technical problems existing in the prior art, and provide a method and device for correcting the state of charge of an automotive battery system. According to the corresponding relationship between the linear working range of the voltage-current curve of the battery and the working conditions, it is possible to determine whether the current working condition is suitable for SOC correction, and perform SOC correction only when the voltage-current curve is in the linear working range, reducing the errors introduced by the correction and improving the reliability of the SOC.

[0008] To achieve the above object of the invention, the following technical solutions are provided:

[0009] In the first aspect, an embodiment of the present invention provides a method for correcting the state of charge of an automotive battery system, the correction method comprising:

[0010] Determine whether the current working condition meets the SOC correction suitability condition; wherein, the SOC correction suitability condition is that the voltage-current curve of the battery is in the linear working range;

[0011] When the current working condition meets the SOC correction suitability condition, execute a preset SOC correction strategy to correct the current SOC.

[0012] Compared with the prior art, the method for correcting the state of charge of an automotive battery system provided in the first aspect of the present invention determines whether the current working condition corresponds to the linear working range of the voltage-current curve of the battery before executing the SOC correction strategy, and performs SOC correction only when the working condition is in the linear working range of the voltage-current curve of the battery, reducing the errors introduced by the correction and improving the reliability of the SOC.

[0013] Further, the process of determining whether the current working condition meets the SOC correction suitability condition specifically includes:

[0014] Determine the current working condition data of the battery; wherein, the working condition data includes voltage data, current data, temperature data, and SOC data;

[0015] Determine whether the current working condition meets the SOC correction suitability condition according to a preset matching rule; wherein, the matching rule is the corresponding relationship between the pre-configured working condition and the voltage-current curve.

[0016] Further, the process of executing a preset SOC correction strategy to correct the current SOC when the current working condition meets the SOC correction suitability condition specifically includes:

[0017] When the current working condition meets the SOC correction suitability condition, determine whether it meets the SOC correction enabling condition; wherein, the SOC correction enabling condition is that the difference between the currently measured voltage and the ampere-hour back-calculated voltage is greater than a preset enabling threshold, the currently measured voltage is the voltage obtained by a voltage sensor, and the ampere-hour back-calculated voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table;

[0018] When meeting the SCO correction enabling condition, execute a preset SOC correction strategy to correct the current SOC.

[0019] Further, after meeting the SCO correction enabling condition, it is determined whether to enable SOC correction through the difference between the currently measured voltage and the ampere-hour back-calculated voltage, avoiding the frequent jitter of SOC caused by the frequent activation of SOC correction.

[0020] Further, the preset correction strategy is: correcting the initial value of SOC of the ampere-hour integration method through the open-circuit voltage method.

[0021] Further, the preset correction strategy is:

[0022] Determine the current voltage confidence level of the battery; wherein, the voltage confidence level is the square of the product of the voltage value measured by the voltage sensor and the measurement accuracy of the voltage sensor;

[0023] Determine the current current confidence level of the battery; wherein, the current confidence level is the square of the product of the current value measured by the current sensor and the measurement accuracy of the current sensor;

[0024] Determine the correction weight according to the voltage confidence level and the current confidence level; wherein, the correction weight is the ratio of the current confidence level to the voltage confidence level;

[0025] Update the initial SOC value of the ampere-hour integration method with the sum of the current SOC value determined by the ampere-hour integration method and the correction increment; wherein, the correction increment is the product of the difference between the current measured voltage and the ampere-hour back-calculated voltage and the correction weight.

[0026] In a second aspect, an embodiment of the present invention provides a device for correcting the state of charge of an automotive battery system, the device comprising:

[0027] A suitability condition determination module, configured to determine whether the current working condition meets the SOC correction suitability condition; wherein, the SOC correction suitability condition is that the voltage-current curve of the battery is in the linear working range;

[0028] A correction execution module, configured to execute a preset SOC correction strategy to correct the current SOC when the current working condition meets the SOC correction suitability condition.

[0029] Compared with the prior art, the method for correcting the state of charge of an automotive battery system provided in the second aspect of the present invention determines whether the current working condition corresponds to the linear working range of the voltage-current curve of the battery before executing the SOC correction strategy, and performs SOC correction only when the working condition is in the linear working range of the voltage-current curve of the battery, reducing the error introduced by the correction and improving the reliability of the SOC.

[0030] Further, the suitability condition determination module is further configured to:

[0031] Determine the current working condition data of the battery; wherein, the working condition data includes voltage data, current data, temperature data, and SOC data;

[0032] Determine whether the current working condition meets the SOC correction suitability condition according to a preset matching rule; wherein, the matching rule is the pre-configured correspondence between the working condition and the voltage-current curve.

[0033] Further, the correction execution module is further configured to:

[0034] When the current working condition meets the SOC correction suitability condition, determine whether it meets the SOC correction start condition; wherein, the SOC correction start condition is that the difference between the current measured voltage and the ampere-hour back-calculated voltage is greater than a preset start threshold, the current measured voltage is the voltage obtained by a voltage sensor, and the ampere-hour back-calculated voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table;

[0035] When meeting the SCO correction start condition, execute a preset SOC correction strategy to correct the current SOC.

[0036] Further, after meeting the SCO correction enabling condition, it is determined whether to enable SOC correction by the difference between the currently measured voltage and the voltage deduced from ampere-hour, avoiding the frequent jitter of SOC caused by frequent activation of SOC correction.

[0037] Further, the preset correction strategy is: correcting the initial SOC value of the ampere-hour integration method by the open-circuit voltage method.

[0038] Further, the preset correction strategy is:

[0039] Determine the current voltage confidence level of the battery; wherein, the voltage confidence level is the square of the product of the voltage value measured by the voltage sensor and the measurement accuracy of the voltage sensor;

[0040] Determine the current current confidence level of the battery; wherein, the current confidence level is the square of the product of the current value measured by the current sensor and the measurement accuracy of the current sensor;

[0041] Determine the correction weight according to the voltage confidence level and the current confidence level; wherein, the correction weight is the ratio of the current confidence level to the voltage confidence level;

[0042] Update the initial SOC value of the ampere-hour integration method by the sum of the current SOC value determined by the ampere-hour integration method and the correction increment; wherein, the correction increment is the product of the difference between the currently measured voltage and the voltage deduced from ampere-hour and the correction weight.

[0043] In a third aspect, an embodiment of the present invention provides an electronic device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, where when the processor executes the program, it implements a method for correcting the state of charge of an automotive battery system as described in any one of the embodiments of the first aspect of the present invention.

[0044] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, where the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to cause a computer to execute a method for correcting the state of charge of an automotive battery system as described in any one of the embodiments of the first aspect of the present invention.

[0045] Since the embodiments of the third and fourth aspects of the present invention execute a method for correcting the state of charge of an automotive battery system as described in any one of the embodiments of the first aspect of the present invention, the embodiments of the third and fourth aspects of the present invention have all the beneficial effects of the embodiments of the first aspect.

[0046] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the present invention. Description of the Drawings

[0047] The present invention will be further described below in conjunction with the accompanying drawings and embodiments;

[0048] Figure 1 It is a schematic flow chart of a method for correcting the state of charge of an automotive battery system in one embodiment.

[0049] Figure 2 It is a schematic flow chart of a method for correcting the state of charge of an automotive battery system in another embodiment.

[0050] Figure 3 It is a structural block diagram of a device for correcting the state of charge of an automotive battery system in one embodiment.

[0051] Figure 4 It is an architecture diagram of a method for correcting the state of charge of a battery in one embodiment.

[0052] Figure 5 It is a schematic diagram of regression fitting of battery characteristic curves under various actual vehicle operating conditions.

[0053] Figure 6 It is a structural block diagram of a computer device in one embodiment. Detailed Embodiments

[0054] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The role of the drawings is to supplement the description in the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the protection scope of the present invention.

[0055] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variation thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, the elements defined by the statement "include..." do not exclude the existence of additional identical elements in the process, method, article or device including the said elements.

[0056] The battery in the embodiments of the present invention can be a battery in which both the positive electrode and the negative electrode can release and receive energy-carrying particles, which is not limited herein. In terms of battery types, the battery can be, but is not limited to, a lithium iron phosphate system battery or a silicon-added system battery. The lithium iron phosphate system battery is a lithium-ion battery in which the positive electrode active material contains lithium iron phosphate, and the silicon-added system battery is a lithium-ion battery in which the negative electrode active material contains silicon. In terms of battery scale, the battery can be a single battery cell, or a battery module or a battery pack, which is not specifically limited in the embodiments of the present invention.

[0057] To facilitate the description of the SOC correction problem of the battery in the real-time state, two concepts, pseudo-static and static, are defined here. We define that the process in which the current continuously remains less than a certain threshold (for example, ±10 A) and can last for a certain period of time (for example, 1 - 10 min) is called a pseudo-static process, and remaining greater than this period of time (for example, more than 10 min) is called static. When the battery is in the static state, the voltage change range is very small. In the pseudo-static state, depending on the working conditions, due to different polarization magnitudes, the voltage may rise or fall significantly.

[0058] To facilitate the understanding of the present invention, before describing the embodiments of the present invention, it is necessary to make a necessary explanation of the SOC correction method in the prior art. Since the current sensor is bound to have measurement errors and its measurement accuracy cannot reach 1, the SOC error accumulated by ampere-hour integration is relatively large after the battery has been running for a long time. It is necessary to use the open-circuit voltage of the battery after it is in the static or pseudo-static state to correct the SOC. This correction method is called the pseudo-static correction method, that is, the method of using the pseudo-static state to correct the SOC of the ampere-hour integration method of the battery. Ah The process is mostly to simply determine that when the current of the current high-voltage bus (I) is less than a certain threshold (for example, 10 A) and lasts for a certain period of time (for example, 10 s), it is considered that the current battery is in the pseudo-static state. After the pseudo-static state ends, the OCV of the current battery is inversely deduced through the formula U = OCV ± IR of the open-circuit voltage method (where OCS represents the open-circuit voltage), and then the SOC of the open-circuit voltage method is obtained according to the OCV-SOC relationship table. OCV Finally, directly correct the SOC Ah to SOC OCV ; where U and I in the formula U = OCV ± IR can be measured by a voltage sensor and a current sensor.

[0059] The inventor of the present invention found that using the open-circuit voltage OCV to correct the SOC AhWhen it is necessary to convert the measured voltage value U into the open-circuit voltage OCV, according to the conversion formula U = OCV ± IR, the applicable condition for the conversion is based on the linear relationship between U and I. However, under certain working conditions, the voltage-current curve (i.e., U-I curve) of the battery will show a non-linear relationship (i.e., non-linear relationship). When the battery is in this non-linear relationship, using the calculated open-circuit voltage OCV to correct the SOC Ah will inevitably introduce new errors and reduce the reliability of the SOC.

[0060] Furthermore, the inventor also found that the open-circuit voltage method calculates the SOC based on the voltage value measured by the voltage sensor, and the ampere-hour integration method calculates the SOC based on the current value measured by the current sensor. Since the ampere-hour integration method needs to integrate the current over time, this integration process will accumulate the errors of the current sensor, while the open-circuit voltage method calculates based on the instantaneous value measured by the voltage sensor and will not accumulate the errors of the voltage sensor. Therefore, the SOC calculated by the ampere-hour integration Ah can be converted into the corresponding voltage value, that is, the ampere-hour back-calculated voltage. By comparing the difference between the ampere-hour back-calculated voltage and the measured voltage obtained by the voltage sensor, the SOC Ah is judged whether the accumulated error is too large and whether the SOC needs to be corrected Ah That is, the condition for starting the SOC correction is reached. That is, the inventor found that the difference between the current measured voltage and the ampere-hour back-calculated voltage can characterize the degree of error accumulation caused by the current sensor. By comparing this difference with the preset start threshold obtained from historical experimental data, the timing for correcting the SOC can be accurately determined.

[0061] Based on the above findings, the following will describe in detail a method and device for correcting the state of charge of an automotive battery system provided by the present invention through multiple embodiments.

[0062] As Figure 1 shown, in one embodiment, a method for correcting the state of charge of an automotive battery system is provided. This correction method runs on a battery management system (Battery Management System, BMS). The battery management system includes a current sensor, a voltage sensor, and a computer device with data transmission and processing capabilities. The computer device can estimate and correct the SOC of the battery and transmit the estimated and corrected SOC data to the display instrument of the vehicle. This correction method includes the following steps:

[0063] Step S102: The computer device determines the current working condition data of the battery.

[0064] It is understandable that the battery management system obtains the operating condition data under various operating conditions through corresponding sensors and reports it to the computer device. These operating condition data include necessary data such as voltage data, current data, temperature data, SOC data, current range and direction, charge and discharge history, and driving conditions.

[0065] As Figure 6 shown, obtaining real vehicle data needs to cover as many operating conditions as possible, such as idling, low-speed driving, medium-speed driving, high-speed driving, low and medium-speed acceleration and deceleration driving, high-speed acceleration and deceleration driving, etc. This can identify the working intervals suitable for enabling pseudo-static correction under various operating conditions to increase the chance of pseudo-static correction.

[0066] Step S104: The computer device determines whether the current operating condition meets the SOC correction suitability condition according to a preset matching rule; wherein, the matching rule is the corresponding relationship between the pre-configured operating condition and the voltage-current curve, and the SOC correction suitability condition is that the voltage-current curve of the battery is in the linear working interval.

[0067] As Figure 6 shown, the pre-configured corresponding relationship between the operating condition and the voltage-current curve is obtained by performing regression fitting on the voltage-current curve of the battery according to the real vehicle data (i.e., operating condition data) obtained in step S102 and the least squares optimization theory, and obtaining the linear working interval of the voltage-current (for example, for a certain battery in the comprehensive endurance condition, within ±60A, 25 - 35°C, and the SOC is between 35% and 85%, the relationship between the voltage and current of the battery can ensure linearity).

[0068] Step S106: When the current operating condition meets the SOC correction suitability condition, the computer device executes a preset SOC correction strategy to correct the current SOC.

[0069] Before the SOC correction is required, the computer device determines whether the current operating condition meets the SOC correction suitability condition under the current operating condition by using the preset matching rule according to the current operating condition fed back by the battery management system. For example, for a certain battery in the comprehensive endurance condition, within ±60A, 25 - 35°C, and the SOC is between 35% and 85%; it is determined that the relationship between the current voltage and current of the battery is in the linear working interval. Specifically, fitting the various operating condition data with a linear equation (y = kx + b) can be achieved using the Excel fitting function or the curve fitting toolbox of MATLAB, which is relatively simple. At this time, the computer device executes the preset SOC correction strategy to correct the current SOC. In one example, the preset correction strategy is to correct the initial value of the SOC of the ampere-hour integration method through the open-circuit voltage method.

[0070] It should be noted that the calculation formula of the ampere-hour integration method is:

[0071]

[0072] Among them, SOC 修正值 is the corrected value of the battery state of charge, and SOC 初始值 is the initial value of the battery state of charge, Q 额定 is the rated capacity of the battery, I is the measured value of the current sensor. When the battery system is in the charging or feedback state, I < 0. When the battery system is in the discharging state, I > 0.

[0073] The specific process of correcting the initial value of SOC of the ampere-hour integration method by the open-circuit voltage method is as follows:

[0074] When the battery has just ended static or pseudo-static, obtain the current voltage value U of the battery through the voltage sensor 测量 , and calculate the open-circuit voltage Uocv according to the formula U 测量 = Uocv ± IR of the open-circuit voltage method; then determine the SOC corresponding to the open-circuit voltage Uocv according to the OCV-SOC relationship table ocv . Use this SOC ocv to correct the SOC 初始值 in the ampere-hour integration method formula, and the corrected ampere-hour integration method formula is as follows:

[0075]

[0076] It can be understood that since the correction method provided in this embodiment can determine whether the current working condition meets the SOC correction suitable condition before correcting the SOC, that is, it can ensure that the SOC correction is performed when the voltage-current curve of the battery is in the linear working range, reducing the error introduced by the correction and improving the reliability of the SOC.

[0077] Such as Figure 2 and Figure 5 shown, in one embodiment, a method for correcting the state of charge of an automotive battery system is provided. This correction method runs on a battery management system (Battery Management System, BMS). The battery management system includes a current sensor, a voltage sensor, and a computer device with data transmission and processing capabilities. The computer device can estimate and correct the SOC of the battery and transmit the estimated and corrected SOC data to the display instrument of the vehicle. This correction method includes the following steps:

[0078] Step S202: The computer device determines the current working condition data of the battery.

[0079] It is understandable that the battery management system obtains the operating condition data under various operating conditions through corresponding sensors and reports it to the computer device. These operating condition data include necessary data such as voltage data, current data, temperature data, SOC data, current range and direction, charge and discharge history, and driving conditions.

[0080] As Figure 6 shown, obtaining real vehicle data needs to cover as many operating conditions as possible, such as idling, low-speed driving, medium-speed driving, high-speed driving, low and medium-speed acceleration and deceleration driving, high-speed acceleration and deceleration driving, etc. This can identify the working intervals suitable for enabling pseudo-static correction under various operating conditions to increase the opportunity of pseudo-static correction.

[0081] Step S204: The computer device determines whether the current operating condition meets the SOC correction suitability condition according to a preset matching rule; wherein, the matching rule is the corresponding relationship between the pre-configured operating condition and the voltage-current curve, and the SOC correction suitability condition is that the voltage-current curve of the battery is in the linear working interval.

[0082] As Figure 6 shown, the pre-configured corresponding relationship between the operating condition and the voltage-current curve is obtained by performing regression fitting on the voltage-current curve of the battery according to the real vehicle data (i.e., operating condition data) obtained in step S102 and the least squares optimization theory, and obtaining the linear working interval of the voltage-current (for example, for a certain battery in the comprehensive endurance condition, within ±60A, 25-35°C, and SOC between 35% and 85%, the relationship between the voltage and current of the battery can ensure linearity). Specifically, fitting the various operating condition data with a linear equation (y = kx + b) can be achieved using the Excel fitting function or the curve fitting toolbox of MATLAB, which is relatively simple.

[0083] Step S206: When the current operating condition meets the SOC correction suitability condition, the computer device determines whether it meets the SOC correction enabling condition; wherein, the SOC correction enabling condition is that the difference between the currently measured voltage and the ampere-hour back-calculated voltage is greater than a preset enabling threshold, the currently measured voltage is the voltage obtained through the voltage sensor, and the ampere-hour back-calculated voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table.

[0084] Specifically, in an example, define the measured voltage as Umeas, the ampere-hour back-calculated voltage as ULUT(SOCah), and the difference between the two as DeltaV. Then the SOC correction enabling condition can be expressed by the following formula:

[0085] DeltaV = |Umeas - ULUT(SOCah)| ≥ a certain threshold (for example, 10mv, can be calibrated)

[0086] It should be noted that the open-circuit voltage method calculates the SOC based on the voltage value measured by the voltage sensor, and the ampere-hour integration method calculates the SOC based on the current value measured by the current sensor. Since the ampere-hour integration method needs to integrate the current over time, this integration process will accumulate the errors of the current sensor, while the open-circuit voltage method calculates based on the instantaneous value measured by the voltage sensor and will not accumulate the errors of the voltage sensor. Therefore, the SOC calculated by the ampere-hour integration can be Ah converted into the corresponding voltage value, that is, the ampere-hour back-calculated voltage. By comparing the difference between the ampere-hour back-calculated voltage and the measured voltage obtained by the voltage sensor, the SOC can be judged. Ah Whether the error accumulated in Ah is too large and whether the SOC needs to be corrected. Ah That is, the condition for starting the SOC correction is met. The difference between the current measured voltage and the ampere-hour back-calculated voltage can characterize the degree of error accumulation caused by the current sensor. The characterization relationship of this degree can be calibrated through prior experiments to determine the starting threshold. Comparing this difference with the preset starting threshold obtained from historical experimental data can accurately determine the timing when the SOC needs to be corrected, avoiding the frequent jitter of the SOC caused by frequent activation of the SOC correction.

[0087] In this embodiment, determining the correction timing requires testing data to understand the polarization recovery characteristics of the battery core and obtaining the battery DC internal resistance data R, reducing the error caused by using the pseudo-static 0th-order model (U = OCV ± IR).

[0088] Step S208: When the computer device meets the SCO correction start condition, execute the preset SOC correction strategy to correct the current SOC.

[0089] It can be understood that in an example of this embodiment, the preset SOC correction strategy can be to correct the initial value of the SOC of the ampere-hour integration method by the open-circuit voltage method. The specific process is as described in the above embodiment and will not be elaborated here.

[0090] In another example, the preset SOC correction strategy includes the following steps:

[0091] Step S2081: Determine the current voltage confidence level of the battery; wherein, the voltage confidence level is the square of the product of the voltage value measured by the voltage sensor and the voltage sensor measurement accuracy.

[0092] That is, voltage confidence level = (voltage measurement value * voltage measurement accuracy)^2

[0093] Step S2082: Determine the current current confidence level of the battery; wherein, the current confidence level is the square of the product of the current value measured by the current sensor and the current sensor measurement accuracy.

[0094] That is, current confidence = (current measurement value * current measurement accuracy)^2

[0095] Step S2083: Determine a correction weight according to the voltage confidence and the current confidence; wherein, the correction weight is the ratio of the current confidence to the voltage confidence.

[0096] That is, the pseudo-static correction weight α = current measurement confidence / voltage measurement confidence

[0097] Step S2084: Update the initial SOC value of the ampere-hour integration method by using the sum of the current SOC value determined by the ampere-hour integration method and the correction increment; wherein, the correction increment is the product of the difference between the currently measured voltage and the voltage inversely deduced by ampere-hour and the correction weight.

[0098] In summary, the formula for updating the initial SOC value of the ampere-hour integration method is as follows:

[0099] SOC 新初始值 = SOC 旧初始值 + α * DeltaV

[0100] wherein, SOC 旧初始值 is the initial SOC value when calculating SOC by the ampere-hour integration method currently, and SOC 新初始值 is the updated initial SOC value.

[0101] It should be noted that the unit of DeltaV is V, but after multiplying by the pseudo-static correction weight α, a correction amount with the same dimension as SOC can be obtained.

[0102] It should be noted that in the correction method provided in this embodiment, based on the statistical probability theory, the confidence of the voltage and current is evaluated by the magnitudes of the voltage and current measurement variances. Assuming that the current and voltage measurement values conform to the Gaussian normal distribution law, the confidence of the two respectively represents the uncertainty of the single-sampling voltage and current. At the same time, the pseudo-static correction weight is the ratio of the current measurement confidence to the voltage measurement confidence, and its physical meaning is that when the voltage measurement is unreliable, the weight of the voltage correction is reduced, and more trust is placed in the result of calculating SOC (ampere-hour integration method) according to the current, and vice versa. Further, the update of the pseudo-static correction SOC is continuously iteratively updated in each calculation cycle, and is continuously corrected to the accurate value according to the correction weight and the current error, while ensuring that the SOC does not have a large jump.

[0103] It should be noted that the Gaussian normal distribution law in probability and statistics theory mentioned in the embodiments of the present invention means that a single measurement and observation of an object may be affected by random errors. However, after multiple measurements and samplings of a large number of samples, the measured values will fluctuate around a relatively stable average value, and the random errors will cancel each other out positively and negatively. Using this principle, within each sampling period, the sampling of voltage and current has a certain degree of uncertainty (i.e., including random errors). Therefore, in each SOC calculation step, it is necessary to consider the impact of this uncertainty on SOC calculation, and determine which of the SOC calculated by the ampere-hour integration method of the circuit and the SOC calculated by the open-circuit voltage method of voltage is more reliable by evaluating this impact, which has a similar idea to the Kalman filtering algorithm.

[0104] Generally speaking, the correction method provided by the embodiments of the present invention identifies the conditions applicable to pseudo-static correction under different working conditions through a large amount of real vehicle voltage-current data (IV curve), and proposes a SOC correction method based on pseudo-static confidence evaluation based on these conditions, improving the reliability and engineering practicability of pseudo-static correction SOC.

[0105] As Figure 3 shown, in one embodiment, a state of charge correction device for an automotive battery system is provided. The device includes:

[0106] A suitable condition determination module 110, configured to determine whether the current working condition meets the SOC correction suitable condition; wherein, the SOC correction suitable condition is that the voltage-current curve of the battery is in the linear working range;

[0107] A correction execution module 120, configured to execute a preset SOC correction strategy to correct the current SOC when the current working condition meets the SOC correction suitable condition.

[0108] In some embodiments, the suitable condition determination module 110 is further configured to:

[0109] Determine the current working condition data of the battery; wherein, the working condition data includes voltage data, current data, temperature data, and SOC data;

[0110] Determine whether the current working condition meets the SOC correction suitable condition according to a preset matching rule; wherein, the matching rule is the pre-configured correspondence between the working condition and the voltage-current curve.

[0111] In some embodiments, the correction execution module is further configured to:

[0112] When the current operating condition meets the SOC correction suitability condition, determine whether the SOC correction start condition is met; wherein, the SOC correction start condition is that the difference between the currently measured voltage and the ampere-hour back-calculated voltage is greater than a preset start threshold, the currently measured voltage is the voltage obtained by a voltage sensor, and the ampere-hour back-calculated voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table;

[0113] When the SCO correction start condition is met, execute a preset SOC correction strategy to correct the current SOC.

[0114] In an alternative embodiment, the preset correction strategy is: correct the initial SOC value of the ampere-hour integration method by the open-circuit voltage method.

[0115] In another alternative embodiment, the preset correction strategy is:

[0116] Determine the current voltage confidence level of the battery; wherein, the voltage confidence level is the square of the product of the voltage value measured by the voltage sensor and the measurement accuracy of the voltage sensor;

[0117] Determine the current current confidence level of the battery; wherein, the current confidence level is the square of the product of the current value measured by the current sensor and the measurement accuracy of the current sensor;

[0118] Determine a correction weight according to the voltage confidence level and the current confidence level; wherein, the correction weight is the ratio of the current confidence level to the voltage confidence level;

[0119] Update the initial SOC value of the ampere-hour integration method by using the sum of the currently determined SOC value by the ampere-hour integration method and the correction increment; wherein, the correction increment is the product of the difference between the currently measured voltage and the ampere-hour back-calculated voltage and the correction weight.

[0120] It should be noted that the device embodiment of the present invention is based on the same inventive concept as the above method embodiment, and will not be elaborated here.

[0121] Figure 4 The internal structure diagram of a computer device in an embodiment is shown. This computer device can specifically be the computer device in a battery management system. Such as Figure 4As shown, the computer device includes a processor, a memory, a network interface, an input device, and a display screen connected via a system bus. Among them, the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor can implement a method for correcting the state of charge of an automotive battery system. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can execute a correction of the state of charge of an automotive battery system. Those skilled in the art can understand, Figure 4 The structure shown in is only a block diagram of some structures related to the solution of the present invention, and does not constitute a limitation on the computer device to which the solution of the present invention is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0122] In one embodiment, a device for correcting the state of charge of an automotive battery system provided in the present application can be implemented in the form of a computer program, and the computer program can run on a computer device as shown in Figure 4 The memory of the computer device may store each program module that constitutes the device for correcting the state of charge of an automotive battery system. For example, Figure 3 the suitable condition determination module 110 and the correction execution module 120 shown in. The computer program constituted by each program module enables the processor to execute the steps in the method for correcting the state of charge of an automotive battery system in each embodiment of the present application described in this specification.

[0123] For example, Figure 4 the computer device shown in can execute the steps of determining the current working condition data of the battery and determining whether the current working condition meets the SOC correction suitable condition according to a preset matching rule through the suitable condition determination module 110 in a device for correcting the state of charge of an automotive battery system as shown in Figure 3 Among them, the working condition data includes voltage data, current data, temperature data, and SOC data; among them, the matching rule is the corresponding relationship between the pre-configured working condition and the voltage-current curve. Through the correction execution module 120, when the current working condition meets the SOC correction suitable condition, execute the preset SOC correction strategy to correct the current SOC.

[0124] In one embodiment, an electronic device is provided, including: a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it performs the steps of the above-mentioned method for correcting the state of charge of an automotive battery system. The steps of the method for correcting the state of charge of an automotive battery system here may be the steps in the method for correcting the state of charge of an automotive battery system in each of the above embodiments.

[0125] In one embodiment, a computer-readable storage medium is provided. The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the steps of the above-mentioned method for correcting the state of charge of an automotive battery system. The steps of the method for correcting the state of charge of an automotive battery system here may be the steps in the method for correcting the state of charge of an automotive battery system in each of the above embodiments.

[0126] Those of ordinary skill in the art can understand that all or part of the processes of implementing the methods in the above embodiments can be completed by instructing relevant hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it may include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided in the present application may include non-volatile and / or volatile memories. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0127] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

Claims

1. A method for correcting the state of charge of an automotive battery system, characterized in that, the correction method includes: Determine whether the current working condition meets the SOC correction suitability condition; wherein, the SOC correction suitability condition is that the voltage-current curve of the battery is in the linear working range; When the current working condition meets the SOC correction suitability condition, execute a preset SOC correction strategy to correct the current SOC.

2. The method for correcting the state of charge of an automotive battery system according to claim 1, characterized in that, The process of determining whether the current working condition meets the SOC correction suitability condition specifically includes: Determine the current working condition data of the battery; wherein, the working condition data includes voltage data, current data, temperature data and SOC data; Determine whether the current working condition meets the SOC correction suitability condition according to a preset matching rule; wherein, the matching rule is the corresponding relationship between the pre-configured working condition and the voltage-current curve.

3. The method for correcting the state of charge of an automotive battery system according to claim 1, characterized in that, The process of executing a preset SOC correction strategy to correct the current SOC when the current working condition meets the SOC correction suitability condition specifically includes: When the current working condition meets the SOC correction suitability condition, determine whether it meets the SOC correction activation condition; wherein, the SOC correction activation condition is that the difference between the currently measured voltage and the ampere-hour back-calculated voltage is greater than a preset activation threshold, the currently measured voltage is the voltage obtained by a voltage sensor, and the ampere-hour back-calculated voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table; When meeting the SCO correction activation condition, execute a preset SOC correction strategy to correct the current SOC.

4. The method for correcting the state of charge of an automotive battery system according to claim 1 or 3, characterized in that, The preset SOC correction strategy is: Correct the initial value of SOC of the ampere-hour integration method by the open-circuit voltage method.

5. The method for correcting the state of charge of an automotive battery system according to claim 3, characterized in that, The preset SOC correction strategy is: Determine the current voltage confidence level of the battery; wherein, the voltage confidence level is the square of the product of the voltage value measured by the voltage sensor and the measurement accuracy of the voltage sensor; Determine the current current confidence level of the battery; wherein, the current confidence level is the square of the product of the current value measured by the current sensor and the measurement accuracy of the current sensor; Determine the correction weight according to the voltage confidence level and the current confidence level; wherein, the correction weight is the ratio of the current confidence level to the voltage confidence level; Update the initial value of SOC of the ampere-hour integration method by using the sum of the current SOC value determined by the ampere-hour integration method and the correction increment; wherein, the correction increment is the product of the difference between the currently measured voltage and the ampere-hour back-calculated voltage and the correction weight.

6. An apparatus for correcting the state of charge of an automotive battery system, characterized in that, the apparatus includes: A suitability condition determination module for determining whether the current working condition meets the SOC correction suitability condition; wherein, the SOC correction suitability condition is that the voltage-current curve of the battery is in the linear working range; A correction execution module, configured to execute a preset SOC correction strategy to correct the current SOC when the current working condition meets the SOC correction suitability condition.

7. An apparatus for correcting the state of charge of an automotive battery system according to claim 6, wherein, the suitability condition determination module is further configured to: determine the current working condition data of the battery; wherein, the working condition data includes voltage data, current data, temperature data, and SOC data; determine whether the current working condition meets the SOC correction suitability condition according to a preset matching rule; wherein, the matching rule is a pre-configured correspondence between the working condition and the voltage-current curve.

8. An apparatus for correcting the state of charge of an automotive battery system according to claim 6, wherein, the correction execution module is further configured to: when the current working condition meets the SOC correction suitability condition, determine whether it meets the SOC correction activation condition; wherein, the SOC correction activation condition is that the difference between the currently measured voltage and the ampere-hour back-calculated voltage is greater than a preset activation threshold, the currently measured voltage is the voltage obtained by a voltage sensor, and the ampere-hour back-calculated voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table; when the SCO correction activation condition is met, execute a preset SOC correction strategy to correct the current SOC.

9. An apparatus for correcting the state of charge of an automotive battery system according to claim 6 or 8, wherein, the preset SOC correction strategy is: correct the initial SOC value of the ampere-hour integration method by the open-circuit voltage method.

10. An apparatus for correcting the state of charge of an automotive battery system according to claim 8, wherein, the preset SOC correction strategy is: determine the current voltage confidence level of the battery; wherein, the voltage confidence level is the square of the product of the voltage value measured by the voltage sensor and the measurement accuracy of the voltage sensor; determine the current current confidence level of the battery; wherein, the current confidence level is the square of the product of the current value measured by the current sensor and the measurement accuracy of the current sensor; determine a correction weight according to the voltage confidence level and the current confidence level; wherein, the correction weight is the ratio of the current confidence level to the voltage confidence level; update the initial SOC value of the ampere-hour integration method by using the sum of the current SOC value determined by the ampere-hour integration method and the correction increment; wherein, the correction increment is the product of the difference between the currently measured voltage and the ampere-hour back-calculated voltage and the correction weight.

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