CN118226262A

CN118226262A - Battery state of charge estimation method and device, energy storage power station and storage medium

Info

Publication number: CN118226262A
Application number: CN202310961994.2A
Authority: CN
Inventors: 张玉; 尹雪芹; 曹虎; 尹小强; 周心焰
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2023-07-31
Filing date: 2023-07-31
Publication date: 2024-06-21

Abstract

The invention discloses a battery state of charge estimation method and device, an energy storage power station and a storage medium, wherein the battery state of charge estimation method comprises the following steps: acquiring battery state parameters and state-of-charge correction method characteristic parameters; determining a characteristic parameter preset interval in the current battery state according to the battery state parameters; and determining a target state of charge estimation mode according to the current state of the battery, the state of charge correction method characteristic parameters and the characteristic parameter preset interval to obtain a state of charge value of the battery, so that the state of charge of the battery can be estimated more accurately, the SOC estimation error is reduced, the method has stronger instantaneity, flexibility and adaptability, and the performance and reliability of a battery management system are improved.

Description

Battery state of charge estimation method and device, energy storage power station and storage medium

Technical Field

The present invention relates to the field of battery energy storage technologies, and in particular, to a battery state of charge estimation method, a battery state of charge estimation device, an energy storage power station, and a computer readable storage medium.

Background

In recent years, as lithium ion battery energy storage systems are widely used in power service fields such as power transmission, power generation, power distribution, electricity consumption and the like, much attention has been paid to how to better utilize batteries. The accurate monitoring of SOC (State of Charge) has become a hot spot in research in the field of battery management systems and even in the field of battery energy storage power stations. The battery SOC reflects the actual available power of the battery and is a very important parameter in the operation of the energy storage power station. Therefore, accurate estimation of SOC has high value, for example: correctly reporting the energy condition of the power station battery so as to be used by a customer according to the requirement; the overcharge and overdischarge of the battery are prevented, and the service life of the battery is prolonged; avoid the occurrence of SOC jump and improve the customer satisfaction.

Currently, commonly used methods for SOC estimation include open circuit voltage method and ampere-hour integration method. Among them, the open circuit voltage method is a method of estimating SOC by measuring an open circuit voltage of a battery. By modeling the relationship between voltage and SOC, the current state of charge of the battery can be inferred from its open circuit voltage value. The ampere-hour integration law estimates SOC by integrating battery charge and discharge current. The method is based on the principle of conservation of charge quantity, and the current SOC is calculated by integrating and accumulating the current and combining the rated capacity and the charge and discharge efficiency of the battery.

However, for the whole charge-discharge process of the battery, each stage, such as the initial stage, the middle stage or the final stage of charge-discharge, the voltage of the battery is different from the variation of the SOC, and the SOC value is estimated by using the open-circuit voltage method or the ampere-hour integration method alone, so that the estimated SOC value has relatively large deviation.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, an object of the present invention is to provide a battery state of charge estimation method, which can more accurately estimate the state of charge of a battery, reduce SOC estimation errors, and have strong real-time performance, flexibility and adaptability, thereby improving the performance and reliability of a battery management system.

A second object of the present invention is to provide a battery state of charge estimation device.

A third object of the present invention is to propose an energy storage plant.

A fourth object of the present invention is to propose a computer readable storage medium.

To achieve the above object, a battery state of charge estimation method according to an embodiment of the first aspect of the present invention includes: acquiring battery state parameters and state-of-charge correction method characteristic parameters; determining a characteristic parameter preset interval in the current battery state according to the battery state parameters; and determining a target state of charge estimation mode according to the current state of the battery, the state of charge correction method characteristic parameters and the characteristic parameter preset interval so as to obtain a state of charge value of the battery.

According to the battery state of charge estimation method provided by the embodiment of the invention, the characteristic parameter preset interval under the current battery state is determined by acquiring the battery state parameter and the state of charge correction method characteristic parameter in real time, and the acquired current battery state parameter, the state of charge correction method characteristic parameter and the characteristic parameter preset interval are combined, so that a proper estimation mode can be flexibly selected according to specific charge and discharge conditions to adapt to battery state of charge estimation requirements under different working conditions and battery states, thereby obtaining more accurate battery state of charge values, improving the accuracy of SOC estimation, reducing SOC estimation errors, having stronger instantaneity, flexibility and adaptability, and improving the performance and reliability of a battery management system.

In some embodiments, the state of charge correction method feature parameter includes a cell voltage or a battery SOC value, the battery state parameter includes a battery current and a battery temperature, and determining a feature parameter preset interval in a current battery state according to the battery state parameter includes: determining a current battery state according to the battery current or the battery voltage, and determining a corresponding battery SOC-voltage curve under the current battery state according to the battery current and the battery temperature; and determining a non-platform area of the battery cell voltage or the battery SOC value on the battery SOC-voltage curve as the preset interval of the characteristic parameter. By considering the influence of battery current and temperature on the battery SOC-voltage relationship, the selected characteristic parameter preset interval is ensured to accurately reflect the state of charge range in the current battery state, so that the accuracy and precision of state of charge estimation are improved.

In some embodiments, determining a target state of charge estimation mode according to the current state of the battery, the state of charge correction method feature parameter and the feature parameter preset interval to obtain a state of charge value of the battery includes: determining that the battery is in a charged state; if the characteristic parameters of the charge state correction method are in a non-platform area on a battery charging SOC-voltage curve, obtaining a charge state value of the battery according to the battery voltage and the battery charging SOC-voltage curve; and if the characteristic parameters of the charge state correction method are in a platform area on a battery charging SOC-voltage curve, obtaining the charge state value of the battery according to an ampere-hour integration method.

In some embodiments, determining a target state of charge estimation mode according to the current state of the battery, the state of charge correction method feature parameter and the feature parameter preset interval to obtain a state of charge value of the battery includes: determining that the battery is in a discharged state; if the characteristic parameters of the charge state correction method are in a non-platform area on a battery discharging SOC-voltage curve, obtaining a charge state value of the battery according to the battery voltage and the battery discharging SOC-voltage curve; and if the characteristic parameters of the charge state correction method are in a platform area on a battery discharging SOC-voltage curve, obtaining the charge state value of the battery according to an ampere-hour integration method.

In some embodiments, obtaining the battery state of charge value according to an ampere-hour integration method comprises: acquiring an SOC value, a battery temperature, a charge-discharge current and a battery SOH value at the last moment; and carrying out ampere-time integral operation according to the SOC value, the battery temperature, the charge-discharge current and the battery SOH value at the last moment to obtain the battery state-of-charge value, so that the real-time state-of-charge of the battery can be reflected more accurately, and the accuracy of SOC estimation is improved.

Performing ampere-time integral operation according to the SOC value, the battery temperature, the charge-discharge current and the battery SOH value at the previous time to obtain the battery state of charge value, including: obtaining the battery state of charge value according to the SOC value at the last moment, the battery temperature, the charge and discharge current and the battery SOH value through the following formula:

Wherein, SOC _N is the state of charge value of the battery, SOC _P is the SOC value of the last moment, η is the coulombic efficiency of charging and discharging of the battery, I is the charging and discharging current, K _C is the charging and discharging current correction factor, K _T is the temperature correction factor, SOH is the battery health, and C _R is the rated capacity of the battery.

In some embodiments, determining a target state of charge estimation mode according to the current state of the battery, the state of charge correction method feature parameter and the feature parameter preset interval to obtain a state of charge value of the battery includes: determining that the battery is in a static state; if the characteristic parameters of the charge state correction method are in a non-platform area on a battery static state of charge (SOC) -voltage curve, obtaining a charge state value of the battery according to battery voltage and the battery static state of charge (SOC) -voltage curve; and if the characteristic parameters of the charge state correction method are in a platform area on a battery static state SOC-voltage curve, updating the charge state value of the battery according to the battery static time.

In some embodiments, updating the battery state of charge value according to the battery rest period includes: if the static time length of the battery is longer than or equal to the preset time length, the state of charge value of the battery is adjusted according to the state of charge change amount of static unit time; and if the standing time of the battery is less than the preset time, maintaining the current state of charge value of the battery.

In order to achieve the above object, a battery state of charge estimation device according to an embodiment of a second aspect of the present invention includes: at least one processor; a memory communicatively coupled to the at least one processor; the memory stores a computer program executable by the at least one processor, which when executed by the at least one processor implements the battery state of charge estimation method described in the above embodiments.

According to the battery state of charge estimation device of the embodiment of the invention, the battery state of charge estimation method described in the above embodiment is adopted. By combining the current battery state parameters, the characteristic parameters of the charge state correction method and the preset intervals of the characteristic parameters, a proper estimation mode can be flexibly selected to adapt to battery charge state estimation requirements under different working conditions and battery states, so that a more accurate battery charge state value is obtained, the accuracy of SOC estimation is improved, the SOC estimation error is reduced, and the method has strong instantaneity, flexibility and adaptability and improves the performance and reliability of a battery management system.

To achieve the above object, an energy storage power station according to an embodiment of a third aspect of the present invention includes: the battery state of charge estimation device of the above embodiment and an energy storage battery, wherein the battery state of charge estimation device is connected with the energy storage battery.

According to the energy storage power station disclosed by the embodiment of the invention, the state of charge of the energy storage battery is accurately estimated by using the battery state of charge estimation method disclosed by the embodiment of the invention, so that the accuracy of battery SOC estimation is improved, the SOC estimation error is reduced, and the method has stronger instantaneity, flexibility and adaptability, and the performance and reliability of the energy storage power station are improved.

To achieve the above object, a computer-readable storage medium of a fourth aspect of the present invention has stored thereon a computer program which, when executed by a processor, implements the battery state of charge estimation method described in the above embodiment.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

FIG. 1 is a flow chart of a battery state of charge estimation method according to one embodiment of the invention;

FIG. 2 is a graph of battery charge SOC versus voltage at different rates at the same temperature according to one embodiment of the invention;

FIG. 3 is a graph of battery discharge SOC versus voltage for different rates at the same temperature in accordance with one embodiment of the present invention;

FIG. 4 is an overall flow chart of a method of estimating state of charge of a battery at different states according to one embodiment of the invention;

fig. 5 is a block diagram of a battery state of charge estimation apparatus according to one embodiment of the present invention;

figure 6 is a block diagram of an energy storage power station according to one embodiment of the present invention.

Reference numerals:

An energy storage power station 1;

A battery state of charge estimation device 10; an energy storage battery 20;

A processor 11; a memory 12.

Detailed Description

Embodiments of the present invention will be described in detail below, by way of example with reference to the accompanying drawings.

A battery state of charge estimation method according to an embodiment of the present invention is described below with reference to fig. 1 to 4.

Fig. 1 is a flowchart of a battery state of charge estimation method according to an embodiment of the present invention, and as shown in fig. 1, the battery state of charge estimation method according to an embodiment of the present invention at least includes the following steps S1 to S3.

S1, acquiring battery state parameters and state-of-charge correction method characteristic parameters.

The battery state parameter may be a physical quantity or index describing the current state of the battery, such as battery current, battery voltage, battery temperature, battery capacity, and battery state of health (SOH), among others. These parameters may be obtained in a variety of ways and methods, such as sensor measurements, battery management systems, embedded measurements, or mathematical model algorithms, and the specific selection will depend on the specific application scenario and requirements.

The characteristic parameters of the state of charge correction method can be understood as parameters for selecting the correction state of charge estimation method, so as to select a proper estimation method based on the parameters corresponding to the specific state and stage of battery charge and discharge, thereby improving estimation accuracy and reliability. For example, the cell voltage or the battery SOC value may be a characteristic parameter of the state of charge correction method.

S2, determining a characteristic parameter preset interval in the current battery state according to the battery state parameters.

The preset interval of the characteristic parameters is a value range or interval of the characteristic parameters determined under a specific battery state, and can be used for guiding the selection or correction of the state of charge estimation method so as to improve the accuracy and reliability of estimation.

Specifically, a correlation model between the battery state parameters and the characteristic parameters can be established through experimental tests, data analysis or mathematical modeling, and state parameters such as current and temperature of the battery are obtained by using methods such as battery management system or sensor measurement and the like, and are monitored in real time. And then, inputting the current battery state parameters into the association model by using the established association model, so as to obtain the corresponding preset interval of the characteristic parameters.

And S3, determining a target state of charge estimation mode according to the current state of the battery, the characteristic parameters of the state of charge correction method and a preset interval of the characteristic parameters so as to obtain a state of charge value of the battery.

The target state of charge estimation mode refers to a specific algorithm or model for estimating the state of charge of the battery, which is determined based on the current state of the battery, the characteristic parameter of the state of charge correction method and a preset interval of the characteristic parameter, for example, an open circuit voltage algorithm or an ampere-hour integration method or other estimation methods.

When the battery is in different states, such as charging or discharging or standing, the change curves of the voltage and the SOC are different, and different voltage and SOC change conditions exist in preset intervals of the characteristic parameters of the state-of-charge correction method, and the state-of-charge value deviation obtained by adopting different SOC estimation methods under the different voltage and SOC change conditions is large.

By selecting a proper estimation mode, the battery state-of-charge estimation requirements under different working conditions and battery states are adapted, and therefore a more accurate battery state-of-charge value is obtained.

In some embodiments, the target state of charge estimation method may include using a physical model-based algorithm, combining current and temperature information of the battery, and performing interpolation or fitting according to a battery SOC-voltage curve in a preset interval of the characteristic parameter, so as to estimate a current state of charge value of the battery. And combining the information such as the current, the temperature and the SOH value of the battery to perform ampere-hour integral operation so as to obtain a more accurate battery state of charge value.

In some embodiments, determining the preset interval of the characteristic parameter in the current battery state according to the battery state parameter specifically includes: the current value of the battery is measured to judge whether the battery is in a charging state, a discharging state or a standing state currently. According to the magnitude and direction of the current, the current charge and discharge state of the battery can be determined. For example, it is defined that: a negative current indicates that the battery is charging, a positive current indicates that the battery is discharging, and a current close to zero indicates that the battery is in a rest state; or defined as: a positive current indicates that the battery is charging, a negative current indicates that the battery is discharging, and a current near zero indicates that the battery is in a rest state. In addition, the current battery state may also be determined from the battery voltage. For example, the voltage of the battery may gradually increase in a charged state, and the voltage of the battery may gradually decrease in a discharged state, and the voltage of the battery remains relatively stable in a stationary state.

Further, on the basis of the determined current battery state, the battery SOC-voltage curve corresponding to the current battery state can be determined by combining parameters such as battery current, battery temperature and the like. This curve describes the relationship between battery SOC (state of charge) and voltage. Through analysis and modeling, the voltage characteristics of the battery under different SOCs can be obtained, and an SOC-voltage curve is formed. This curve can be used as a reference to help estimate the current state of charge of the battery.

It should be noted that the relationship between the voltage variation of the battery and the charge/discharge state may be affected by the type and specification of the battery. Therefore, in practical applications, specific analysis and modeling are required for a specific type of battery to obtain more accurate battery state estimation results.

In some embodiments, considering the influence of factors such as temperature, current conditions and multiplying power (charge and discharge rate of a battery) on a battery SOC-voltage curve, a plurality of curves can be established to describe the battery SOC-voltage relationship under different conditions through experimental measurement, modeling simulation or calculation based on battery characteristic parameters. As shown in fig. 2 and 3, taking a lithium iron phosphate battery as an example, fig. 2 shows SOC-voltage curves of batteries at the same temperature and different charge rates in a charged state. Fig. 3 shows battery SOC-voltage curves for the same temperature and different discharge rates in the discharged state.

Further, according to the obtained battery SOC-voltage curve, determining a non-platform area of the battery cell voltage or the battery SOC value on the curve as a preset area of the characteristic parameter for further charge state estimation.

The reason that the non-platform area of the battery SOC-voltage curve is used as the preset area of the characteristic parameter is that the non-platform area reflects the non-linear behavior of the battery and the sensitivity of the change of the state of charge. In the non-platform area, larger change and response exist between the voltage or SOC value and the state of charge of the battery, so that the actual state of charge of the battery can be reflected more accurately by selecting the non-platform area as a preset area of the characteristic parameters. For example: as shown in fig. 2 and 3, the preset interval of the characteristic parameter may be that the SOC is below 20% or above 80%, and the voltage in this interval has a relatively obvious change along with the change of the SOC.

In some embodiments, the target state of charge estimation mode is determined according to the current state of charge, the characteristic parameter of the state of charge correction method and the preset interval of the characteristic parameter, so as to obtain the state of charge value of the battery, which can be divided into the following three cases for detailed description.

For the first case, if it is determined that the battery is in a state of charge, it is necessary to determine the region where the state of charge correction method characteristic parameter (i.e., the cell voltage or the battery SOC value) is on the battery charge SOC-voltage curve, so as to ensure that an appropriate target state of charge estimation mode is adopted to obtain the battery state of charge value.

Specifically, the region where the characteristic parameter is on the battery charge SOC-voltage curve may be determined by comparing the relationship between the characteristic parameter and the curve. If the characteristic parameters of the charge state correction method are in the non-platform area on the battery charging SOC-voltage curve, interpolation or fitting is carried out according to the battery voltage and the battery charging SOC-voltage curve so as to obtain the corresponding charge state value of the battery. This may be achieved by using numerical analysis or mathematical modeling techniques. Common methods include linear interpolation, polynomial fitting, curve fitting, and the like.

If the characteristic parameter of the state of charge correction method is in a plateau region on the battery charge SOC-voltage curve, i.e. a region in which the voltage in the battery charge SOC-voltage curve remains relatively stable, the state of charge value of the battery cannot be accurately estimated directly by the battery voltage. This is because in the plateau region, the voltage change of the battery is not significant and does not provide enough information to determine a specific state of charge. In this case, the state of charge value of the battery can be estimated more accurately using the ampere-hour integration method.

For the second case, if it is determined that the battery is in a discharge state, it is also possible to determine the region where the characteristic parameter is on the battery discharge SOC-voltage curve by comparing the relationship between the characteristic parameter and the curve. If the characteristic parameters of the charge state correction method are in the non-platform area on the battery discharging SOC-voltage curve, interpolation or fitting operation is carried out according to the battery voltage and the battery discharging SOC-voltage curve so as to obtain the corresponding charge state value of the battery. And if the characteristic parameters of the charge state correction method are in a platform area on the battery discharging SOC-voltage curve, obtaining the charge state value of the battery according to an ampere-hour integration method.

In some embodiments, the SOC value, battery temperature, charge-discharge current, and battery SOH value at the last time need to be obtained before the battery state-of-charge value is calculated according to the ampere-hour integration method. The SOC value represents the state of charge of the battery, the battery temperature represents the current temperature, the charge/discharge current represents the current direction and magnitude of the battery, and the SOH value represents the health of the battery.

Further, an ampere-hour integral operation is performed according to the SOC value, the battery temperature, the charge-discharge current and the battery SOH value at the last moment, so as to obtain the battery state of charge value. The specific formula is as follows:

The SOC _N is a state of charge value of the battery, the SOC _P is a SOC value of the last moment, η is a coulomb efficiency of charging and discharging of the battery, and the SOC is used for considering a capacity loss in a charging and discharging process, and the SOC value can be approximately 1 at normal temperature, which represents a ratio between an actual discharge capacity and a charge capacity. I is charge-discharge current (positive in discharge and negative in charge), and K _C is a charge-discharge current correction factor for considering the influence of charge-discharge current on the state of charge of the battery. K _T is a temperature correction factor for taking into account the effect of battery temperature on the state of charge of the battery. SOH is the battery health for taking into account the effects of battery aging and capacity fade on the state of charge of the battery. C _R is the battery rated capacity, i.e., the nominal capacity of the battery at design time.

In some embodiments, in order to more accurately estimate the state of charge of the battery, the test system may perform charge and discharge experiments under different multiplying power and different temperature conditions, and perform fitting according to experimental data, so as to obtain a charge and discharge current correction factor (K _C), a temperature correction factor (K _T) and a battery health (SOH) suitable for different conditions.

For the third case, if it is determined that the battery is in a stationary state, that is, the battery is not subjected to the charge-discharge operation. This can be determined by monitoring the magnitude of the current. If the current is close to zero or very small, the battery can be considered to be in a stationary state. And in a static state, judging whether the characteristic parameters are in a non-platform area on a static state SOC-voltage curve of the battery according to the characteristic parameters (namely the battery voltage or the battery SOC value) of the charge state correction method. If the characteristic parameter is in the non-platform area, the state of charge of the battery is obviously changed. At this time, interpolation or fitting operation may be performed according to the battery voltage and the battery rest SOC-voltage curve to obtain a corresponding battery state of charge value.

If the characteristic parameters of the charge state correction method are in a platform area on a battery static state of charge (SOC) -voltage curve, the charge state change of the battery is not obvious, and the voltage is kept relatively stable. In this case, an accurate state of charge value cannot be directly obtained from the battery voltage. Accordingly, the battery state of charge value may be updated according to the battery rest period.

The standing time period of the battery refers to the time period during which the battery stands without performing a charge and discharge operation. In general, the self-discharge rate of the battery is relatively small, and the longer the standing time period is, the smaller the change in the state of charge is. Therefore, the state of charge value of the battery can be updated by using the information of the standing time of the battery so as to more accurately reflect the current state of charge of the battery.

Specifically, if the resting time period of the battery is greater than or equal to the preset time period, it is indicated that the battery has been resting for a relatively long time period. In this case, the state of charge value of the battery can be adjusted by standing the state of charge change amount per unit time. In this way, the state of charge of the battery can be updated to more accurately reflect the current state based on the self-discharge or other effects of the battery during rest.

If the standing time of the battery is less than the preset time, the standing time of the battery is relatively short. In this case, in order to avoid excessive adjustment based on a short rest period, it may be selected to maintain the state of charge value of the current battery unchanged. This is because the change in state of charge of the battery may not be noticeable or reliable for a short rest period, and thus maintaining the current value may avoid unnecessary adjustments.

Further, it is noted that the setting of the preset time period needs to be based on knowledge of the characteristics and the use environment of the battery, and takes into account the self-discharge rate of the battery during standing and the reliability of the change in the state of charge.

Fig. 4 is an overall flowchart of a battery state of charge estimation method under different states according to an embodiment of the present invention, as shown in fig. 4, including the steps of:

S10, starting.

S11, acquiring parameters such as current, voltage, temperature and the like of the battery through a battery management system.

S12, judging whether the battery is in a charging state, if so, proceeding to step S13, and if not, proceeding to step S17.

S13, judging whether the characteristic parameters of the charge state correction method are in a characteristic parameter preset interval (a non-platform area on a battery charge SOC-voltage curve) in a charge state, if so, entering a step S14, and if not, entering a step S15.

S14, correcting the SOC value according to the temperature, the current and the cell voltage.

S15, introducing corresponding correction factors to conduct ampere-hour integral calculation according to the current temperature, current and SOH of the battery.

S16, obtaining the SOC value at the current moment in the charging state.

S17, judging whether the battery is in a discharging state, if so, proceeding to step S18, and if not, proceeding to step S22.

S18, judging whether the characteristic parameters of the charge state correction method are in a characteristic parameter preset interval (a non-platform area on a battery discharging SOC-voltage curve) in a discharging state, if so, proceeding to step S19, and if not, proceeding to step S20.

S19, correcting the SOC value according to the temperature, the current and the cell voltage.

S20, introducing corresponding correction factors to conduct ampere-hour integral calculation according to the current temperature, current and SOH of the battery.

S21, obtaining the SOC value at the current moment in the discharging state.

S22, judging whether the battery is in a static state, if so, proceeding to step S23, otherwise, proceeding to step S

S23, judging whether the characteristic parameters of the charge state correction method are in a characteristic parameter preset interval (a non-platform area on a battery static state SOC-voltage curve) in a static state, if so, proceeding to step S24, and if not, proceeding to step S25.

S24, correcting the SOC value according to the temperature, the current and the cell voltage.

S25, judging whether the standing time is greater than or equal to the preset time, if so, entering step S26, and if so, entering step S27.

S26, adjusting the SOC value of the battery according to the state of charge variation of the standing unit time.

S27, keeping the SOC value unchanged.

S28, ending.

In summary, the characteristic parameter preset interval of the current battery state (i.e. the charging state, the discharging state, and the standing state) is determined by acquiring the battery state parameter and the characteristic parameter of the charge state correction method in real time, and the non-platform area of the battery cell voltage or the battery SOC value on the battery SOC-voltage curve is determined as the characteristic parameter preset interval. When the cell voltage or the battery SOC value is in a non-plateau region on the battery SOC-voltage curve, the battery state of charge value may be obtained from the battery current, the battery temperature, and the battery cell voltage. When the battery cell voltage or the battery SOC value is in a platform region on a battery SOC-voltage curve, corresponding correction factors can be introduced to conduct ampere-hour integral calculation according to the SOC value, the battery temperature, the charge-discharge current and the battery SOH value at the last moment, so that a more accurate battery state-of-charge value is obtained, the accuracy of SOC estimation is improved, the SOC estimation error is reduced, and the method has strong instantaneity, flexibility and adaptability, and the performance and reliability of a battery management system are improved.

A battery state of charge estimation device according to an embodiment of the present invention is described below with reference to fig. 5.

Fig. 5 is a block diagram of a battery state of charge estimation device according to an embodiment of the present invention, and as shown in fig. 5, a battery state of charge estimation device 10 according to an embodiment of the present invention includes at least one processor 11 and a memory 12.

The memory 12 is communicatively connected to the at least one processor 11, and the memory 12 stores a computer program executable by the at least one processor 11, where the at least one processor 11 executes the computer program to implement the battery state of charge estimation method of the above embodiments.

In the embodiment, the battery state of charge estimation device 10 is an electronic device, has functions of monitoring, calculating and correcting the battery state of charge, and can be widely applied to the fields of electric automobiles, battery energy storage systems and the like, so as to provide key battery state information for users and improve the use efficiency and reliability of batteries.

According to the battery state-of-charge estimation device 10 of the embodiment of the present invention, by adopting the battery state-of-charge estimation method of the above embodiment, and combining the current battery state parameter, the characteristic parameter of the state-of-charge correction method and the preset interval of the characteristic parameter, a suitable estimation mode can be flexibly selected to adapt to the battery state-of-charge estimation requirements under different working conditions and battery states, so as to obtain a more accurate battery state-of-charge value, improve the accuracy of SOC estimation, reduce the SOC estimation error, and have stronger instantaneity, flexibility and adaptability, and improve the performance and reliability of the battery management system.

An energy storage power station according to an embodiment of the invention is described below with reference to fig. 6.

Fig. 6 is a block diagram of an energy storage power station according to an embodiment of the invention, as shown in fig. 6, the energy storage power station 1 of an embodiment of the invention comprises an energy storage battery 20 and a battery state of charge estimation device 10 as described in the above embodiments.

The energy storage battery 20 is a device for storing electric energy, and is typically composed of a plurality of battery cells, such as a lithium iron phosphate battery, a lithium ion battery, a lead acid battery, a sodium ion battery, and the like. These battery cells are capable of storing electrical energy and releasing it when needed for supply to an electrical power system or load.

In some embodiments, the battery state of charge estimation device 10 is coupled to the energy storage battery 20 to enable communication and data interaction. The method and the device have the advantages that various parameters of the battery, such as current, voltage, temperature and the like, are obtained in real time, and the state of charge of the battery is accurately estimated and predicted by using an algorithm and a model, so that an important basis is provided for battery management and control.

According to the energy storage power station 1 of the embodiment of the invention, the state of charge of the energy storage battery 20 is accurately estimated by using the battery state of charge estimation method described in the embodiment, so that the accuracy of battery SOC estimation is improved, the SOC estimation error is reduced, and the method has strong instantaneity, flexibility and adaptability, and the performance and reliability of the energy storage power station 1 are improved.

The embodiment of the invention also provides a computer readable storage medium, on which a computer program is stored, which when executed by a processor implements the battery state of charge estimation method described in the above embodiment. The specific implementation of the battery state of charge estimation method may be described with reference to the above embodiments.

The computer readable storage medium according to the embodiments of the present invention may include, but is not limited to, a phase change memory (PRAM), a Static Random Access Memory (SRAM), a Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), a Read Only Memory (ROM), an Electrically Erasable Programmable Read Only Memory (EEPROM), a flash memory, or other optical and magnetic storage media, which are not described in detail herein.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method of estimating a state of charge of a battery, comprising:

Acquiring battery state parameters and state-of-charge correction method characteristic parameters;

determining a characteristic parameter preset interval in the current battery state according to the battery state parameters;

and determining a target state of charge estimation mode according to the current state of the battery, the state of charge correction method characteristic parameters and the characteristic parameter preset interval so as to obtain a state of charge value of the battery.

2. The battery state of charge estimation method according to claim 1, wherein the state of charge correction method characteristic parameters include a cell voltage or a battery SOC value, the battery state parameters include a battery current and a battery temperature, and determining a characteristic parameter preset interval in a current battery state according to the battery state parameters includes:

Determining a current battery state according to the battery current or the battery voltage;

Determining a corresponding battery SOC-voltage curve under the current battery state according to the battery current and the battery temperature;

And determining a non-platform area of the battery cell voltage or the battery SOC value on the battery SOC-voltage curve as the preset interval of the characteristic parameter.

3. The battery state of charge estimation method according to claim 2, wherein determining a target state of charge estimation manner according to the current battery state, the state of charge correction method characteristic parameter, and the characteristic parameter preset interval to obtain a battery state of charge value comprises:

Determining that the battery is in a charged state;

If the characteristic parameters of the charge state correction method are in a non-platform area on a battery charging SOC-voltage curve, obtaining a charge state value of the battery according to the battery voltage and the battery charging SOC-voltage curve;

and if the characteristic parameters of the charge state correction method are in a platform area on a battery charging SOC-voltage curve, obtaining the charge state value of the battery according to an ampere-hour integration method.

4. The battery state of charge estimation method according to claim 2, wherein determining a target state of charge estimation manner according to the current battery state, the state of charge correction method characteristic parameter, and the characteristic parameter preset interval to obtain a battery state of charge value comprises:

Determining that the battery is in a discharged state;

if the characteristic parameters of the charge state correction method are in a non-platform area on a battery discharging SOC-voltage curve, obtaining a charge state value of the battery according to the battery voltage and the battery discharging SOC-voltage curve;

And if the characteristic parameters of the charge state correction method are in a platform area on a battery discharging SOC-voltage curve, obtaining the charge state value of the battery according to an ampere-hour integration method.

5. The battery state of charge estimation method according to claim 3 or 4, wherein obtaining the battery state of charge value according to an ampere-hour integration method comprises:

Acquiring an SOC value, a battery temperature, a charge-discharge current and a battery SOH value at the last moment;

and carrying out ampere-time integral operation according to the SOC value at the last moment, the battery temperature, the charge and discharge current and the battery SOH value to obtain the battery state of charge value.

6. The battery state of charge estimation method according to claim 5, wherein performing an ampere-hour integration operation based on the SOC value at the previous time, the battery temperature, the charge-discharge current, and the battery SOH value to obtain the battery state of charge value, comprises:

obtaining the battery state of charge value according to the SOC value at the last moment, the battery temperature, the charge and discharge current and the battery SOH value through the following formula:

Wherein, SOC _N is the state of charge value of the battery, SOC _P is the SOC value of the last moment, η is the coulombic efficiency of charging and discharging of the battery, I is the charging and discharging current, K _C is the charging and discharging current correction factor, K _T is the temperature correction factor, SOH battery health, and C _R is the rated capacity of the battery.

7. The battery state of charge estimation method according to claim 2, wherein determining a target state of charge estimation manner according to the current battery state, the state of charge correction method characteristic parameter, and the characteristic parameter preset interval to obtain a battery state of charge value comprises:

Determining that the battery is in a static state;

If the characteristic parameters of the charge state correction method are in a non-platform area on a battery static state of charge (SOC) -voltage curve, obtaining a charge state value of the battery according to battery voltage and the battery static state of charge (SOC) -voltage curve;

And if the characteristic parameters of the charge state correction method are in a platform area on a battery static state SOC-voltage curve, updating the charge state value of the battery according to the battery static time.

8. The battery state of charge estimation method according to claim 7, wherein updating the battery state of charge value according to the battery rest period comprises:

If the static time length of the battery is longer than or equal to the preset time length, the state of charge value of the battery is adjusted according to the state of charge change amount of static unit time;

And if the standing time of the battery is less than the preset time, maintaining the current state of charge value of the battery.

9. A battery state of charge estimation apparatus, comprising:

at least one processor;

a memory communicatively coupled to the at least one processor;

Stored in the memory is a computer program executable by the at least one processor, which when executed by the at least one processor implements the battery state of charge estimation method of any one of claims 1-8.

10. An energy storage power station comprising an energy storage battery and the battery state of charge estimation device of claim 9, the battery state of charge estimation device being connected to the energy storage battery.

11. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the battery state of charge estimation method according to any one of claims 1-8.