CN114763076A - Method and device for correcting charge state of automobile battery system - Google Patents

Abstract

The invention discloses a method and a device for correcting the state of charge of an automobile battery system, and relates to the technical field of batteries. The correction method can determine whether the current working condition is suitable for the current working condition according to the corresponding relationship between the linear working interval of the voltage-current curve of the battery and the working condition. SOC correction is performed, and the SOC correction is performed only when the voltage-current curve is in the working range of a straight line, so as to reduce the error introduced by the correction and improve the reliability of the SOC. At the same time, before executing the SOC correction strategy, first determine whether the current working condition corresponds to the voltage-current curve of the battery in the linear working range, and only perform SOC correction when the voltage-current curve of the battery is in the working condition corresponding to the linear working range. Reduce the error introduced by the correction and improve the reliability of the SOC. Further, after the SCO correction start condition is met, the difference between the current measured voltage and the ampere-hour reverse voltage is used to determine whether the SOC correction needs to be turned on, so as to avoid frequent SOC jitter caused by frequently starting the SOC correction.

Description

A method and device for correcting state of charge of a vehicle battery system

technical field

The invention relates to the technical field of batteries, in particular to a method and device for correcting the state of charge of an automobile battery system.

Background technique

As the core component of new energy vehicles, the power battery system is crucial to the development of new energy vehicles. The battery management system (Battery Management System, BMS) is the core component of the power battery system, and the state of charge (State Of Charge, SOC) of the power system is the core technical parameter of the BMS. As a direct reflection of battery power, SOC provides a reference for the driver to estimate the remaining mileage on the one hand, and an important basis for battery management and maintenance on the other hand. In addition, SOC is the basis of other BMS control algorithms. If there is no accurate SOC, add more The protection function also cannot make the BMS work normally, because the battery will be constantly in the protection state, and it cannot prolong the life of the battery, so its accuracy and robustness are extremely important.

In the related art, commonly used SOC correction methods include an open circuit voltage method and an ampere-hour integration method. Among them, the open circuit voltage method uses the corresponding relationship between the open circuit voltage (Open-Circuit Voltage, OCV) and the SOC to obtain the SOC of the battery in a steady state (also called static state). The ampere-hour integration rule is to use a current sensor to measure the current of the battery during the working process of the battery, integrate the charging and discharging current of the battery with time, and then estimate the dynamic SOC value of the battery.

Since the ampere-hour integration method has high requirements on the current sampling accuracy, otherwise a large cumulative error may occur after long-term operation. There are also methods that combine the open-circuit voltage method and the ampere-hour integration method. After the battery runs for a long time, the SOC error accumulated by the ampere-hour integration is relatively large, and the SOC needs to be corrected by using the open circuit voltage of the battery in static or pseudo-static state. This correction method is called pseudo-static correction method, that is, a method of correcting the SOC _Ah of the battery ampere-hour integral method using pseudo-static correction. After a period of time (for example, 10s), the current battery is considered to be in pseudo-static state, and then the OCV of the current battery is deduced by the formula of the open circuit voltage method U=OCV±IR (where OCS represents the open circuit voltage), and then according to the OCV-SOC relationship table The SOC _OCV of the open circuit voltage method is obtained, and finally the SOC _Ah is directly corrected to SOC _OCV .

However, the above pseudo-static correction method has the following shortcomings: when using the pseudo-static correction SOC under certain operating conditions, it will introduce new errors to the SOC and reduce the reliability of the SOC.

SUMMARY OF THE INVENTION

It should be noted that one of the contributions of the present inventor to the prior art is to discover the reason why a new error will be introduced to the SOC when using the pseudo-static correction SOC under certain operating conditions: due to the use of the open circuit voltage OCV 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, it can be known that the applicable condition of conversion is a linear relationship based on UI. However, under certain operating conditions, the voltage-current curve (ie, UI curve) of the battery will exhibit a nonlinear relationship (ie, a nonlinear relationship). When the battery is in this nonlinear relationship, the converted open circuit voltage OCV is used to correct it. SOC _Ah , will inevitably introduce new errors and reduce the reliability of SOC.

Based on the above findings, the purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a method and device for correcting the state of charge of an automobile battery system, according to the linear working interval and working conditions of the voltage-current curve of the battery. It can determine whether the current operating condition is suitable for SOC correction, and perform SOC correction only when the voltage-current curve is in the linear operating range, reducing errors introduced by correction and improving SOC reliability.

In order to realize the above-mentioned purpose of the invention, the following technical solutions are provided:

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

determining whether the current operating condition complies with the SOC correction suitable condition; wherein, the SOC correction suitable condition is that the voltage-current curve of the battery is in a linear working range;

When the current operating conditions meet the suitable conditions for SOC correction, a preset SOC correction strategy is executed to correct the current SOC.

Compared with the prior art, in a method for correcting the state of charge of a vehicle battery system provided by the first aspect of the present invention, before executing the SOC correction strategy, it is first determined whether the current operating condition corresponds to the voltage-current curve of the battery in a linear operating range. , when the voltage-current curve of the battery is in the working condition corresponding to the linear working range, the SOC correction is performed to reduce the error introduced by the correction and improve the reliability of the SOC.

Further, the process of determining whether the current operating condition meets the SOC correction suitable conditions specifically includes:

determining current operating condition data of the battery; wherein, the operating condition data includes voltage data, current data, temperature data and SOC data;

Whether the current operating condition meets the SOC correction suitable condition is determined according to a preset matching rule; wherein, the matching rule is a pre-configured corresponding relationship between the operating conditions and the voltage-current curve.

Further, the process of executing a preset SOC correction strategy to correct the current SOC when the current operating condition meets the suitable conditions for SOC correction, specifically includes:

When the current operating condition meets the SOC correction suitable condition, it is determined whether the SOC correction start condition is met; wherein, the SOC correction start condition is that the difference between the current measured voltage and the ampere-hour reverse voltage is greater than the preset start threshold, and the current The measured voltage is the voltage obtained by the voltage sensor, and the ampere-hour inversion voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table;

When the SCO correction opening condition is met, a preset SOC correction strategy is executed to correct the current SOC.

Further, after meeting the SCO correction turn-on condition, it is judged whether the SOC correction needs to be turned on by the difference between the current measured voltage and the ampere-hour reversed voltage, so as to avoid frequent SOC jitter caused by frequently starting the SOC correction.

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

Further, the preset correction strategy is:

determining 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;

determining the 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 degree and the current confidence degree; wherein, the correction weight is the ratio of the current confidence degree and the voltage confidence degree;

Utilize the sum of the current SOC value determined by the ampere-hour integral method and the correction increment to update the SOC initial value of the ampere-hour integral method; wherein, the correction increment is the difference between the current measured voltage and the ampere-hour reverse voltage and the The product of the correction weights.

In a second aspect, an embodiment of the present invention provides an apparatus for correcting the state of charge of a vehicle battery system, the apparatus comprising:

a suitable condition determination module, 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 a straight working range;

The correction execution module is configured to execute a preset SOC correction strategy to correct the current SOC when the current operating condition meets the suitable conditions for SOC correction.

Compared with the prior art, in a method for correcting the state of charge of a vehicle battery system provided by the second aspect of the present invention, before executing the SOC correction strategy, it is first determined whether the current operating condition corresponds to the voltage-current curve of the battery in a linear operating range. , when the voltage-current curve of the battery is in the working condition corresponding to the linear working range, the SOC correction is performed to reduce the error introduced by the correction and improve the reliability of the SOC.

Further, the suitable condition determination module is also used for:

determining current operating condition data of the battery; wherein, the operating condition data includes voltage data, current data, temperature data and SOC data;

Whether the current operating condition meets the SOC correction suitable condition is determined according to a preset matching rule; wherein, the matching rule is a pre-configured corresponding relationship between the operating conditions and the voltage-current curve.

Further, the correction execution module is also used for:

When the current operating condition meets the SOC correction suitable condition, it is determined whether the SOC correction start condition is met; wherein, the SOC correction start condition is that the difference between the current measured voltage and the ampere-hour reverse voltage is greater than the preset start threshold, and the current The measured voltage is the voltage obtained by the voltage sensor, and the ampere-hour inversion voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table;

When the SCO correction opening condition is met, a preset SOC correction strategy is executed to correct the current SOC.

Further, after meeting the SCO correction turn-on condition, it is judged whether the SOC correction needs to be turned on by the difference between the current measured voltage and the ampere-hour reversed voltage, so as to avoid frequent SOC jitter caused by frequently starting the SOC correction.

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

Further, the preset correction strategy is:

determining 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;

determining the 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 degree and the current confidence degree; wherein, the correction weight is the ratio of the current confidence degree and the voltage confidence degree;

Utilize the sum of the current SOC value determined by the ampere-hour integral method and the correction increment to update the SOC initial value of the ampere-hour integral method; wherein, the correction increment is the difference between the current measured voltage and the ampere-hour reverse voltage and the The product of the correction weights.

In a third aspect, an embodiment of the present invention provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and running on the processor, when the processor executes the program, the computer program as described in the first embodiment of the present invention is implemented. In one aspect, a method for correcting the state of charge of a vehicle battery system according to any one of the embodiments.

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 the embodiment of the first aspect of the present invention. A method for correcting the state of charge of a vehicle battery system according to any one of the above.

Since the embodiments of the third aspect and the fourth aspect of the present invention implement the method for correcting the state of charge of a vehicle battery system according to any one of the embodiments of the first aspect of the present invention, the third and fourth aspects of the present invention Embodiments of the aspect have all of the benefits of the embodiments of the first aspect.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

Below in conjunction with accompanying drawing and embodiment, the present invention is further described;

FIG. 1 is a schematic flowchart of a method for correcting the state of charge of a vehicle battery system in one embodiment.

FIG. 2 is a schematic flowchart of a method for correcting the state of charge of a vehicle battery system in another embodiment.

FIG. 3 is a structural block diagram of an apparatus for correcting the state of charge of a vehicle battery system in one embodiment.

FIG. 4 is a structural diagram of a battery state-of-charge correction method in one embodiment.

Figure 5 is a schematic diagram of the regression fitting of the battery characteristic curve under various actual vehicle operating conditions.

FIG. 6 is a structural block diagram of a computer device in one embodiment.

Detailed ways

This part will describe the specific embodiments of the present invention in detail, and the preferred embodiments of the present invention are shown in the accompanying drawings. Each technical feature and overall technical solution of the invention should not be construed as limiting the protection scope of the invention.

It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element defined by the phrase "comprises" does not preclude the presence of additional identical elements in a process, method, article, or device that includes the element.

The battery in the embodiment of the present invention may be a battery in which both the positive electrode and the negative electrode can be detached 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. Lithium-ion batteries containing silicon. In terms of battery scale, the battery may be a single battery cell, or a battery module or a battery pack, which is not specifically limited in the embodiment of the present invention.

In order to conveniently describe the SOC correction problem of the battery in real-time state, two concepts are defined here, pseudo-static and static. We define the process that the current continues to be less than a certain threshold (for example, ±10A) and can last for a period of time (for example, 1-10min) is called a pseudo-static process, and the process that remains longer than this period of time (for example, more than 10min) is called static. When the battery is in static state, the voltage variation range is very small. In pseudo-static state, the voltage may rise or drop by a large margin due to the different polarizations according to different working conditions.

In order to facilitate the understanding of the present invention, before describing the embodiments of the present invention, it is necessary to describe the SOC correction method in the prior art. Due to the inevitable measurement error of the current sensor, its measurement accuracy cannot reach 1. After the battery runs for a long time, the SOC error accumulated by the ampere-hour integration is relatively large. It is necessary to use the open-circuit voltage of the battery in static or pseudo-static state to correct the SOC. This correction method is called pseudo-static correction method, that is, a method of correcting the SOC _Ah of the battery ampere-hour integral method using pseudo-static correction. After a period of time (for example, 10s), the current battery is considered to be in pseudo-static state. After the pseudo-static state is over, the OCV of the current battery is deduced by the formula of the open circuit voltage method U=OCV±IR (where OCS represents the open circuit voltage), and then according to the OCV The SOC _OCV of the open-circuit voltage method is obtained from the -SOC relationship table, and finally SOC _Ah is directly corrected to SOC _OCV ; where U and I in the formula U=OCV±IR can be obtained by measuring the voltage sensor and the current sensor.

The inventors found that when using the open circuit voltage OCV to correct the SOC _Ah , the measured voltage value U needs to be converted into the open circuit voltage OCV. According to the conversion formula U=OCV±IR, the applicable condition of conversion is a linear relationship based on UI. However, under certain operating conditions, the voltage-current curve (ie UI curve) of the battery will show a nonlinear relationship (ie, a nonlinear relationship). When the battery is in this nonlinear relationship, the converted open circuit voltage OCV is used to correct it. SOC _Ah , will inevitably introduce new errors and reduce the reliability of SOC.

Further, the inventors have also found that the open-circuit voltage method calculates the SOC according to the voltage value measured by the voltage sensor, and the ampere-hour integration method calculates the SOC according to the current value measured by the current sensor. Perform integration, this integration process will accumulate the error of the current sensor, while the open-circuit voltage method is calculated based on the instantaneous value measured by the voltage sensor, and will not accumulate the error of the voltage sensor, so the SOC _Ah calculated by the ampere-hour integration can be converted into the corresponding The voltage value, that is, the ampere-hour reverse voltage. By comparing the difference between the ampere-hour reverse voltage and the measured voltage measured by the voltage sensor, it is judged whether the accumulated error in SOC _Ah is too large, and whether SOC _Ah needs to be corrected. SOC correction turn-on condition. That is, the inventor found that the difference between the current measured voltage and the ampere-hour reverse voltage can represent the degree of error accumulation caused by the current sensor, and the difference is compared with the preset turn-on threshold obtained through historical experimental data. Yes, so the timing when SOC needs to be corrected can be accurately determined.

Based on the above findings, a method and device for correcting the state of charge of a vehicle battery system provided by the present invention will be described in detail below through multiple embodiments.

As shown in FIG. 1 , in one embodiment, a method for correcting the state of charge of an automobile battery system is provided. The correcting method runs on a battery management system (Battery Management System, BMS). The battery management system includes a current sensor, a 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 car. The correction method includes the following steps:

Step S102: The computer device determines the current operating condition data of the battery.

It can be understood that the battery management system obtains the working condition data under each working condition through the corresponding sensor and reports it to the computer equipment. These working condition data include voltage data, current data, temperature data, SOC data, current range and direction, charging. Necessary data such as discharge history and driving conditions.

As shown in Figure 6, the acquisition of real vehicle data needs to cover as many working conditions as possible, such as idling, low-speed driving, medium-speed driving, high-speed driving, low-medium-speed acceleration and deceleration driving, high-speed acceleration and deceleration driving, etc. A working range suitable for enabling pseudo-static correction under various working conditions is selected to improve the chance of pseudo-static correction.

Step S104: the computer device determines whether the current operating condition complies with the SOC correction suitable condition according to the preset matching rule; wherein, the matching rule is a pre-configured corresponding relationship between the operating condition and the voltage-current curve, and the SOC correction suitable condition The voltage-current curve of the battery is in a straight line working range.

As shown in FIG. 6 , the pre-configured corresponding relationship between the working conditions and the voltage-current curve is based on the actual vehicle data (ie, the working condition data) obtained in step S102 and the least squares optimization theory, to determine the voltage-current curve of the battery. Perform regression fitting on the curve to obtain the linear working range of voltage-current (for example, a certain battery is within ±60A, 25-35°C, SOC is between 35%-85%, and the battery voltage The relationship with the current can be guaranteed to be linear).

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

Before the SOC correction needs to be performed, the computer device uses a preset matching rule to determine whether the current operating conditions meet the SOC correction suitable conditions according to the current operating conditions fed back by the battery management system. For example, if a certain battery is within ±60A, 25 to 35°C, and SOC is between 35% and 85% in the comprehensive battery life condition, it is determined that the current relationship between the voltage and current of the battery is in the linear working range. Specifically, it is relatively simple to perform linear equation (y=kx+b) fitting on the data of various working conditions, which can be realized by using the Excel fitting function or the curve fitting toolbox of MATLAB. At this time, the computer device executes a preset SOC correction strategy to correct the current SOC. In one example, the preset correction strategy is to correct the initial SOC value of the ampere-hour integration method by the open circuit voltage method.

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

Among them, the SOC _{correction value is} the correction value of the battery state of charge, the initial SOC value is the _{initial value of} the battery state of charge, Q is the _rated capacity of the battery, and 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 discharge state, I>0.

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

When the battery has just finished static or pseudo-static, the current voltage value U _measurement of the battery is obtained through the voltage sensor, and the open circuit voltage Uocv is calculated according to the formula of the open circuit voltage method U _measurement = Uocv ± IR; The SOC ocv corresponding to the voltage _Uocv . Modify the SOC _ocv to the _{initial value} of SOC in the ampere-hour integral method formula, and obtain the revised ampere-hour integral method formula as follows:

It can be understood that, because the correction method provided in this embodiment can determine in advance whether the current operating condition meets the suitable conditions for SOC correction 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 operating range, Reduce the error introduced by the correction and improve the reliability of the SOC.

As shown in FIG. 2 and FIG. 5 , in one embodiment, a method for correcting the state of charge of an automobile battery system is provided. The correcting method runs on a battery management system (Battery Management System, BMS). The battery management system includes: Current sensor, voltage sensor and computer equipment with data transmission and processing capabilities, the computer equipment can estimate and correct the SOC of the battery, and transmit the estimated and corrected SOC data to the display instrument of the car. The correction method includes the following steps:

Step S202: The computer device determines the current operating condition data of the battery.

It can be understood that the battery management system obtains the working condition data under each working condition through the corresponding sensor and reports it to the computer equipment. These working condition data include voltage data, current data, temperature data, SOC data, current range and direction, charging. Necessary data such as discharge history and driving conditions.

As shown in Figure 6, the acquisition of real vehicle data needs to cover as many working conditions as possible, such as idling, low-speed driving, medium-speed driving, high-speed driving, low-medium-speed acceleration and deceleration driving, high-speed acceleration and deceleration driving, etc. A working range suitable for enabling pseudo-static correction under various working conditions is selected to improve the chance of pseudo-static correction.

Step S204: The computer device determines whether the current operating condition complies with the SOC correction suitable condition according to the preset matching rule; wherein, the matching rule is a pre-configured corresponding relationship between the operating condition and the voltage-current curve, and the SOC correction suitable condition The voltage-current curve of the battery is in a straight line working range.

As shown in FIG. 6 , the pre-configured corresponding relationship between the working conditions and the voltage-current curve is based on the actual vehicle data (ie, the working condition data) obtained in step S102 and the least squares optimization theory, to determine the voltage-current curve of the battery. Perform regression fitting on the curve to obtain the linear working range of voltage-current (for example, a certain battery is within ±60A, 25-35°C, SOC is between 35%-85%, and the battery voltage The relationship with the current can be guaranteed to be linear). Specifically, it is relatively simple to perform linear equation (y=kx+b) fitting on the data of various working conditions, which can be realized by using the Excel fitting function or the curve fitting toolbox of MATLAB.

Step S206 : when the current operating condition meets the SOC correction suitable condition, the computer device determines whether the SOC correction start condition is met; wherein, the SOC correction start condition is that the difference between the current measured voltage and the ampere-hour reverse voltage is greater than a preset start Threshold, the currently measured voltage is the voltage obtained by the voltage sensor, and the ampere-hour inversion voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table.

Specifically, in an example, the measured voltage is defined as Umeas, the ampere-hour reverse voltage is defined as ULUT (SOCah), and the difference between the two is DeltaV, then the SOC correction turn-on condition can be expressed as the following formula:

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

It should be noted that the open-circuit voltage method calculates the SOC according to the voltage value measured by the voltage sensor, and the ampere-hour integration method calculates the SOC according to the current value measured by the current sensor. Since the ampere-hour integration method needs to integrate the current over time, this The integration process will accumulate the error of the current sensor, while the open-circuit voltage method is calculated based on the instantaneous value measured by the voltage sensor, and will not accumulate the error of the voltage sensor. Therefore, the SOC _Ah calculated by the ampere-hour integration can be converted into the corresponding voltage value, namely Ampere-hour reverse voltage, by comparing the difference between the ampere-hour reverse voltage and the measured voltage measured by the voltage sensor, to determine whether the accumulated error in SOC _Ah is too large, and whether SOC _Ah needs to be corrected, that is, the SOC correction opening condition is reached. . The difference between the current measured voltage and the ampere-hour reverse voltage can characterize the degree of error accumulation caused by the current sensor, and the characterization relationship of this degree can be calibrated by performing experiments in advance to determine the turn-on threshold. The difference is compared with a preset turn-on threshold obtained through historical experimental data, so as to accurately determine when the SOC needs to be corrected, and avoid frequent SOC jitters caused by frequent SOC corrections.

In this embodiment, the determination of the correction timing requires testing data to find out the polarization rebound characteristics of the battery cell, and obtain the battery DC internal resistance data R, which reduces the error caused by using the pseudo-static 0-order model (U=OCV±IR).

Step S208: When the computer device meets the SCO correction enabling condition, executes a preset SOC correction strategy to correct the current SOC.

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

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

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 measurement accuracy of the voltage sensor.

That is, voltage confidence=(voltage measurement value*voltage measurement accuracy)^2

Step S2082: Determine the 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.

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

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

That is, pseudo-static correction weight α=confidence of current measurement/confidence of voltage measurement

Step S2084: Use the sum of the current SOC value determined by the ampere-hour integral method and the correction increment to update the SOC initial value of the ampere-hour integral method; wherein, the correction increment is the sum of the current measured voltage and the ampere-hour reversed voltage. The product of the difference and the correction weight.

In summary, the formula for updating the initial SOC value of the Ampere-hour integration method is as follows:

SOC _{new initial value} = SOC _{old initial value} + α*DeltaV

Wherein, the _{old initial value} of the SOC is the initial value of the SOC when the SOC is currently calculated by the ampere-hour integration method, and the _{new initial value} of the SOC is the initial value of the SOC after the update.

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

It should be noted that, in the correction method provided in this embodiment, based on the statistical probability theory, the magnitude of the voltage and current measurement variance is used to evaluate the confidence of the two. Assuming that the current and voltage measurement values conform to the Gaussian normal distribution law, then The confidence levels of the two represent the uncertainty of a single sampled voltage and current, respectively. 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 the result of calculating the SOC (Ampere-hour integration method) based on the current is more believed. ,vice versa. Further, the update of the pseudo-static correction SOC is iteratively updated every calculation cycle, and is continuously corrected to an accurate value according to the correction weight and the current error, while ensuring that the SOC does not undergo a large jump.

It should be noted that the Gaussian normal distribution law in the probability and statistics theory mentioned in the embodiment of the present invention means that a single measurement and observation of an object may be affected by random errors, but after multiple measurements and sampling of a large number of samples, The measured value will fluctuate around a relatively stable average value, and random errors will cancel each other out. Using this principle, in each sampling period, the sampling of voltage and current has a certain uncertainty (that is, contains random errors), so this uncertainty needs to be considered in each SOC calculation step. By evaluating this effect, it is determined 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 the voltage is more reliable. It has a similar idea to the Kalman filter algorithm.

In a nutshell, the correction method provided by the embodiment of the present invention identifies the conditions under which the pseudo-static correction can be applied under different operating conditions through a large amount of actual vehicle voltage-current data (IV curves), and based on the conditions, proposes an SOC based on the pseudo-static confidence evaluation. Correction method to improve the reliability and engineering practicability of pseudo-static correction SOC.

As shown in FIG. 3 , in one embodiment, an apparatus for correcting the state of charge of an automobile battery system is provided, and the apparatus includes:

The suitable condition determination module 110 is configured to determine whether the current operating condition meets the SOC correction suitable condition; wherein, the SOC correction suitable condition is that the voltage-current curve of the battery is in a straight working range;

The correction execution module 120 is configured to execute a preset SOC correction strategy to correct the current SOC when the current operating condition meets the SOC correction suitable condition.

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

determining current operating condition data of the battery; wherein, the operating condition data includes voltage data, current data, temperature data and SOC data;

Whether the current operating condition meets the SOC correction suitable condition is determined according to a preset matching rule; wherein, the matching rule is a pre-configured corresponding relationship between the operating conditions and the voltage-current curve.

In some embodiments, the modification execution module is further configured to:

When the current operating condition meets the SOC correction suitable condition, it is determined whether the SOC correction start condition is met; wherein, the SOC correction start condition is that the difference between the current measured voltage and the ampere-hour reverse voltage is greater than the preset start threshold, and the current The measured voltage is the voltage obtained by the voltage sensor, and the ampere-hour inversion voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table;

When the SCO correction opening condition is met, a preset SOC correction strategy is executed to correct the current SOC.

In an optional embodiment, the preset correction strategy is: correcting the initial SOC value of the ampere-hour integration method by the open circuit voltage method.

In another optional embodiment, the preset correction strategy is:

determining 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;

determining the 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 degree and the current confidence degree; wherein, the correction weight is the ratio of the current confidence degree and the voltage confidence degree;

Utilize the sum of the current SOC value determined by the ampere-hour integral method and the correction increment to update the SOC initial value of the ampere-hour integral method; wherein, the correction increment is the difference between the current measured voltage and the ampere-hour reverse voltage and the The product of the correction weights.

It should be noted that the apparatus embodiments of the present invention and the above-mentioned method embodiments are based on the same inventive concept, and are not repeated here.

Figure 4 shows an internal structure diagram of a computer device in one embodiment. The computer device may specifically be a computer device in a battery management system. As shown in FIG. 4 , the computer equipment includes a processor, a memory, a network interface, an input device, and a display screen connected through a system bus. Wherein, 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 also stores 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 a vehicle battery system. A computer program may also be stored in the internal memory, and when executed by the processor, the computer program may cause the processor to perform a state-of-charge correction of a vehicle battery system. Those skilled in the art can understand that the structure shown in FIG. 4 is only a block diagram of a partial structure related to the solution of the present invention, and does not constitute a limitation on the computer equipment to which the solution of the present invention is applied. Include more or fewer components than shown in the figures, or combine certain components, or have a different arrangement of components.

In one embodiment, the apparatus for correcting the state of charge of a vehicle battery system provided by the present application may be implemented in the form of a computer program, and the computer program may be executed on the computer device as shown in FIG. 4 . The memory of the computer device can store various program modules constituting the apparatus for correcting the state of charge of a vehicle battery system, for example, the suitable condition determination module 110 and the correction execution module 120 shown in FIG. 3 . The computer program constituted by each program module enables the processor to execute the steps in a method for correcting the state of charge of a vehicle battery system according to various embodiments of the present application described in this specification.

For example, the computer device shown in FIG. 4 can use the suitable condition determination module 110 in an apparatus for correcting the state of charge of an automobile battery system as shown in FIG. The step of whether the current operating condition complies with the SOC correction suitable conditions, wherein the operating condition data includes voltage data, current data, temperature data and SOC data; wherein, the matching rule is a pre-configured operating condition and a voltage-current curve corresponding relationship. The step of executing a preset SOC correction strategy to correct the current SOC is performed by the correction execution module 120 when the current operating condition meets the SOC correction suitable condition.

In one embodiment, an electronic device is provided, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the above-mentioned car battery when executing the program The steps of the system state of charge correction method. The steps of the method for correcting the state of charge of a vehicle battery system herein may be the steps in the method for correcting the state of charge of a vehicle battery system in the above-mentioned various embodiments.

In one embodiment, a computer-readable storage medium is provided, and the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to cause a computer to execute the above-mentioned state of charge of a vehicle battery system The steps to correct the method. The steps of the method for correcting the state of charge of a vehicle battery system herein may be the steps in the method for correcting the state of charge of a vehicle battery system in the above-mentioned various embodiments.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented by instructing relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium , when the program is executed, it may include the flow of the above-mentioned method embodiments. Wherein, any reference to memory, storage, database or other medium used in the various embodiments provided in this application may include non-volatile and/or volatile memory. Nonvolatile 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 (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous chain Road (Synchlink) DRAM (SLDRA), memory bus (Rambus) direct RAM (RDRA), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features It is considered to be the range described in this specification.

Claims (10)

1. A method for correcting the state of charge of an automobile battery system, wherein the correcting method comprises: determining whether the current operating condition complies with the SOC correction suitable condition; wherein, the SOC correction suitable condition is that the voltage-current curve of the battery is in a linear working range; When the current operating conditions meet the suitable conditions for SOC correction, a preset SOC correction strategy is executed to correct the current SOC. 2 . The method for correcting the state of charge of an automobile battery system according to claim 1 , wherein the process of determining whether the current operating condition meets the suitable conditions for SOC correction specifically includes: 3 . determining current operating condition data of the battery; wherein, the operating condition data includes voltage data, current data, temperature data and SOC data; Whether the current operating condition meets the SOC correction suitable condition is determined according to a preset matching rule; wherein, the matching rule is a pre-configured corresponding relationship between the operating conditions and the voltage-current curve. 3 . The method for correcting the state of charge of an automobile battery system according to claim 1 , wherein when the current operating condition meets the SOC correction suitable conditions, a preset SOC correction strategy is executed to correct the current SOC. 4 . process, including: When the current operating condition meets the SOC correction suitable condition, it is determined whether the SOC correction start condition is met; wherein, the SOC correction start condition is that the difference between the current measured voltage and the ampere-hour reverse voltage is greater than the preset start threshold, and the current The measured voltage is the voltage obtained by the voltage sensor, and the ampere-hour inversion voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table; When the SCO correction opening condition is met, a preset SOC correction strategy is executed to correct the current SOC. 4. The method for correcting the state of charge of a vehicle battery system according to claim 1 or 3, wherein the preset correction strategy is: The SOC initial value of the ampere-hour integration method is corrected by the open-circuit voltage method. 5. The method for correcting the state of charge of a vehicle battery system according to claim 1 or 3, wherein the preset correction strategy is: determining the current voltage confidence of the battery; wherein the voltage confidence is the square of the product of the voltage value measured by the voltage sensor and the measurement accuracy of the voltage sensor; determining the 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 degree and the current confidence degree; wherein, the correction weight is the ratio of the current confidence degree to the voltage confidence degree; Utilize the sum of the current SOC value determined by the ampere-hour integration method and the correction increment to update the SOC initial value of the ampere-hour integral method; wherein, the correction increment is the difference between the current measured voltage and the ampere-hour reverse voltage and the The product of the correction weights. 6. A device for correcting the state of charge of an automobile battery system, characterized in that the device comprises: a suitable condition determination module, 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 a straight working range; The correction execution module is configured to execute a preset SOC correction strategy to correct the current SOC when the current operating condition meets the suitable conditions for SOC correction. 7. The device for correcting the state of charge of an automobile battery system according to claim 6, wherein the suitable condition determination module is further used for: determining current operating condition data of the battery; wherein, the operating condition data includes voltage data, current data, temperature data and SOC data; It is determined whether the current operating condition meets the SOC correction suitable condition according to a preset matching rule; wherein, the matching rule is a pre-configured corresponding relationship between the operating conditions and the voltage-current curve. 8. The device for correcting the state of charge of an automobile battery system according to claim 6, wherein the correction execution module is further used for: When the current operating condition meets the SOC correction suitable condition, it is determined whether the SOC correction start condition is met; wherein, the SOC correction start condition is that the difference between the current measured voltage and the ampere-hour reverse voltage is greater than the preset start threshold, and the current The measured voltage is the voltage obtained by the voltage sensor, and the ampere-hour inversion voltage is the open-circuit voltage determined according to the ampere-hour integration method and the OCV-SOC relationship table; When the SCO correction opening condition is met, a preset SOC correction strategy is executed to correct the current SOC. 9. A vehicle battery system state-of-charge correction device according to claim 6 or 8, wherein the preset correction strategy is: The SOC initial value of the ampere-hour integration method is corrected by the open-circuit voltage method. 10. A vehicle battery system state-of-charge correction device according to claim 6 or 8, wherein the preset correction strategy is: determining the current voltage confidence of the battery; wherein the voltage confidence is the square of the product of the voltage value measured by the voltage sensor and the measurement accuracy of the voltage sensor; determining the 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 degree and the current confidence degree; wherein, the correction weight is the ratio of the current confidence degree to the voltage confidence degree; Utilize the sum of the current SOC value determined by the ampere-hour integration method and the correction increment to update the SOC initial value of the ampere-hour integral method; wherein, the correction increment is the difference between the current measured voltage and the ampere-hour reverse voltage and the The product of the correction weights.

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