CN103499794B - A kind of energy-storage battery Residual capacity prediction method and device - Google Patents

Abstract

A kind of energy-storage battery Residual capacity prediction method and device. The SOC (residual capacity) of the method and device real-time estimation energy-storage battery, mainly comprises the following steps: obtain the parameters such as battery cell voltage, battery temperature, battery pack current; Ampere-hour integration real-time estimation SOCi (based on the residual capacity of electric current), history by electric current discharge and recharge ampere-hour data; And proofread and correct under given conditions estimation SOCv (based on the residual capacity of voltage) by open-circuit voltage; One of them is set to the SOC of energy-storage battery group SOCi and SOCv, and SOC and history are discharged and recharged to ampere-hour data scheduled store. Being embodied as the scheduling of energy-storage system energy provides Data support, makes full use of energy-storage battery capacity, prevents that super-charge super-discharge from occurring, and improves the objects such as battery.

Description

A method and device for estimating the remaining capacity of an energy storage battery

technical field

The invention belongs to the technical field of battery management, in particular to battery management applied to large-scale energy storage systems.

Background technique

Due to the inherent intermittent and random characteristics of new energy generation such as wind energy and solar energy, it will have adverse effects on the safe and stable operation of the power grid. The development of energy storage technology can improve its operation quality. A reasonable and efficient battery management system plays a vital role in the life of the battery stack and the safety of the entire energy storage system.

The rise of the battery management system is closely related to the promotion of electric vehicles in recent years. The battery management system of electric vehicles mainly includes functions such as battery protection, battery instantaneous power estimation, mileage estimation, and insulation detection. The application of power batteries to wind power energy storage is still in its infancy in China. Unlike electric vehicles, the number of batteries required for general energy storage is large and the cost is huge. How to make full use of the capacity of energy storage batteries and prolong their service life, It is the top priority of long-term operation and development of energy storage projects.

This application aims at the energy dispatching requirements of the energy storage system, and proposes a relatively accurate and reliable remaining capacity estimation method and device, which can estimate the SOC of the battery pack in real time, record historical operation data, and make full use of the battery capacity under the premise of protecting the battery safety. service life.

Contents of the invention

The object of the present invention is to provide an accurate and practical method and device for estimating the remaining capacity of an energy storage battery.

This application specifically adopts the following technical solutions:

A method for estimating the remaining capacity of an energy storage battery, characterized in that: the estimation method measures parameters such as the voltage of a battery cell, the temperature of a battery, and the current of a series battery pack, and uses a combination of an ampere-hour integral of the current and correction of the open circuit voltage of a cell method, real-time estimation of the remaining capacity SOCi of the battery pack based on the current data of the battery pack and the remaining capacity SOCv of the battery pack based on the voltage data of the battery pack, and use one of the SOCi and SOCv to set the remaining capacity SOC of the battery pack; At the same time as the integration, the historical charging and discharging ampere-hour data is accumulated, and the historical charging and discharging ampere-hour and remaining capacity SOC are regularly input to the memory for storage.

Further, the estimation method specifically includes the following steps:

(1) Read the SOC initial value of the remaining capacity of the battery pack in the memory, and the initial value of the historical charging and discharging ampere-hour data;

(2) Obtain corresponding voltage data, temperature data, and current data by measuring parameters such as the battery cell voltage, battery temperature, and series battery pack current;

(3) By accumulating the current data, the current of the battery pack is integrated in ampere hours, and the remaining capacity SOCi of the battery pack based on the current data of the battery pack is calculated, and the SOCi is set as the remaining capacity SOC of the battery pack. Discharge ampere-hour data;

(4) Measure the resting time of the energy storage battery. When the resting time reaches the desired time, according to the cell voltage and battery temperature of the energy storage battery, the remaining capacity SOCv of the battery pack based on the battery cell voltage data is obtained;

(5) judge the difference between SOCv and SOCi, when the difference between the two is greater than the set threshold value, set SOCv as the SOC of the battery pack;

(6) Periodically write the historical charging and discharging ampere-hour data and SOC of the energy storage battery pack into the non-volatile memory.

Further, said calculating SOCi comprises the following steps:

3.1 Determine the current direction of the battery pack. If the current is positive, it means that the energy storage battery is charging, and the ampere-hour integration result increases. If the current is negative, it means that the energy storage battery is discharging, and the ampere-hour integration result decreases;

3.2 Periodically execute the ampere-hour integral calculation of the battery pack current. This application sets the ampere-hour integral calculation cycle to 1 millisecond:

Ah _(k) = Ah _(k-1) +I _k

SOCi=SOC0+Ah _(k) /(K*Cnom);

Among them, Ah _(k) : the ampere-hour integral value at the current moment; Ah _(k-1) : the ampere-hour integral value obtained during the last ampere-hour integral operation; I _k : the current current value, when the energy storage battery is charged, I _k is Positive, I _k is negative during discharge; SOCi: battery pack remaining capacity based on battery pack current data; SOC0: battery pack remaining capacity SOC initial value; Cnom: battery rated capacity;

K: unit conversion coefficient, which is the number of times of ampere-hour integration calculations completed within one hour, if the ampere-hour integration period is 1 millisecond, then K=3600s/1ms=3600000;

3.3 Periodically execute historical charging and discharging ampere-hour accumulation. The historical charging and discharging ampere-hour represents the total ampere-hours of charging and discharging of the energy storage battery since the first operation of the energy storage system:

When the energy storage battery is charging:

Total_In_Ah _(k) = Total_In_Ah _(k-1) + I _k

Total_Ah_In＝Total_Ah_In0+Total_In_Ah _(k) /K

When the energy storage battery is discharged:

Total_Out_Ah _(k) = Total_Out_Ah _(k-1) + I _k

Total_Ah_Out＝Total_Ah_Out0+Total_Out_Ah _(k) /K

Among them, Total_In_Ah _(k) : the historical charging ampere-hour integral value at the current moment; Total_In_Ah _(k-1) : the historical charging ampere-hour integral value of the last historical charging and discharging ampere-hour integration; Total_Ah_In: historical charging ampere-hour; Total_Ah_In0: The initial value of historical charging ampere-hour; Total_Out_Ah _(k) : the historical discharge ampere-hour integral value at the current moment; Total_Out_Ah _(k-1) : the historical discharge ampere-hour integral value of the last historical charge-discharge ampere-hour integration; Total_Ah_Out: historical discharge Ah; Total_Ah_Out0: Initial value of historical discharge Ah; K: Same as the definition of K in step 3.2

Further, the calculation of SOCv includes the following steps:

4.1 Judging whether the battery resting time has reached the expected time value;

4.2 When the standing time reaches the expected time value, judge whether the maximum battery voltage is in the high battery range or whether the minimum battery voltage is in the low battery range;

4.3 If the two conditions in 4.2 are met at the same time, then estimate SOCv according to the corresponding relationship between battery open circuit voltage and SOC at different temperatures.

Further, the desired time is 120 seconds;

The high and low battery intervals correspond to 90%-100% and 0%-10% of the SOC respectively.

Further, when the difference between SOCv and SOCi is greater than 2%, SOCv is taken as the new SOC value of the battery pack.

Further, in the case of open-circuit voltage correction, if the highest cell voltage falls into the high-charge range, the SOC value corresponding to the highest cell voltage is used as the SOCv of the battery pack; if the lowest cell voltage falls into the low-charge range , the SOC value corresponding to the lowest cell voltage is set as the SOCv of the battery pack.

The present application also discloses a device for estimating the remaining capacity of an energy storage battery using the above method for estimating the remaining capacity, including:

The cell voltage and temperature acquisition part measures the battery cell voltage data and temperature data, and transmits the voltage and temperature data to the battery information computing part through the CAN bus;

The battery pack current acquisition part measures the current data of the battery pack and transmits it to the battery information calculation part through the SCI bus;

The battery information calculation unit receives the cell voltage data, temperature data, and battery pack current data, estimates SOCi and SOCv, and sets one of the SOCi and SOCv as the SOC of the battery pack, and accumulates historical charging and discharging ampere hours, Control the reading and writing of the battery information storage unit;

The battery information storage unit stores the SOC of the battery pack and historical charging and discharging ampere hours in real time.

Further, the unit voltage and temperature acquisition part mainly includes LT6802-2 dedicated battery management chip, surface mount thermistor, MCU1 for reading the voltage and temperature data of the unit, and CAN communication interface.

LT6802-2 transmits the measured cell voltage and temperature data to MCU1 through the SPI bus;

MCU1 uploads the single voltage and temperature data to the battery information computing department through CAN communication;

The surface mount thermistor is fixed on the pole of the battery.

Further, the battery pack current acquisition part mainly includes a bidirectional Hall current sensor, a current signal conditioning circuit, and a current signal reading processor MCU2.

The bidirectional Hall current sensor is connected in series with the total positive terminal of the battery pack, and can output bidirectional analog voltage according to different current directions;

The current signal conditioning circuit judges the direction of the analog voltage output by the bidirectional Hall current sensor, outputs the direction signal to MCU2, filters the positive analog voltage output by the bidirectional Hall current sensor and connects it to MCU2, and inverts the negative analog voltage And after filtering, connect to MCU2;

The current signal reading processor MCU2 reads the above-mentioned current direction signal, judges the current direction, and performs AD conversion on the analog voltage output by the bidirectional Hall current sensor, calculates the current value, accumulates the battery current value in real time, and periodically The current value and the accumulated result of the current value are transmitted to the processor MCU3 of the battery information operation part through the SCI bus. After each current accumulation result is transmitted to MCU3, the current accumulation result in MCU2 is cleared.

Further, the battery information calculation unit includes a battery information calculation processor MCU3 and a CAN communication interface.

MCU3 receives the monomer voltage and temperature data uploaded by MCU1, and the current value and current accumulation value uploaded by MCU2. Estimate the SOCi of the battery pack by accumulating current data; judge the standing time, estimate the SOCv of the battery pack according to the voltage and temperature of the cells, and finally set one of the SOCi and SOCv as the SOC of the battery pack.

Further, the battery information calculation unit, while estimating the SOC, accumulates the historical charging and discharging ampere hours, and writes the historical charging and discharging ampere hours and SOC into the battery information storage unit.

Further, the battery information storage unit is composed of a non-volatile memory with a model number of FM3164 and its peripheral circuits.

The processor MCU3 of the battery information calculation part performs read and write operations on the above-mentioned non-volatile memory through the IIC bus.

The application has the following beneficial effects:

Use ampere-hour integration to estimate the remaining capacity of the energy storage system and historical charge and discharge data in real time. Make full use of the resting time of the battery, realize the open circuit voltage correction simply and conveniently, reduce the estimation error caused by the ampere-hour integration, and improve the SOC estimation accuracy. Ultimately, reliable data support is provided for the energy dispatch of the energy storage system, and the capacity of the energy storage battery is fully utilized.

Description of drawings

Figure 1 is a schematic flow chart of the method for estimating the remaining capacity of an energy storage battery in this application;

Fig. 2 is a schematic structural diagram of the device for estimating the remaining capacity of the energy storage battery of the present application;

Figure 3 is a bidirectional Hall current sensor output signal processing circuit.

detailed description

The embodiment of the present invention is described in detail below according to accompanying drawing:

As shown in Figure 1, it is a schematic flow chart of the method for estimating the remaining capacity of the energy storage battery in this application. The method for estimating the remaining capacity of the energy storage battery includes the following steps:

1. Read the initial value of the SOC of the energy storage battery and the initial value of the historical charging and discharging ampere hours, read three times in a row, and judge the reading results. If the results are the same three times, enter the next step, otherwise read the initial value again.

2. Circularly detect the cell voltage, temperature and battery current of the energy storage battery pack.

3. Judging the current, if the current of the battery pack is non-zero, perform ampere-hour integration to estimate the remaining capacity SOCi of the battery pack based on the current data of the battery pack, assign SOCi to the remaining capacity SOC of the battery pack, and accumulate the historical charging and discharging ampere-hours . The specific calculation formula is as follows:

Ah _(k) = Ah _(k-1) +I _k

SOCi=SOC0+Ah _(k) /(K*Cnom);

Total_In_Ah _(k) = Total_In_Ah _(k-1) +I _k (I>0)

Total_Ah_In＝Total_Ah_In0+Total_In_Ah _(k) /K(I>0)

Total_Out_Ah _(k) = Total_Out_Ah _(k-1) +I _k (I<0)

Total_Ah_Out＝Total_Ah_Out0+Total_Out_Ah _(k) /K(I<0)

Ah _(k) —Ampere-hour integral value at the current moment

Ah _(k-1) — the ampere-hour integral value obtained during the last ampere-hour integral calculation

I _k — current current value, I _{k is positive when the energy storage battery is charging, and I k is} negative when discharging

SOCi—Battery pack remaining capacity based on battery pack current data;

SOC0—the initial value of SOC of the remaining capacity of the battery pack

Cnom—battery rated capacity

K: unit conversion coefficient, which is the number of times of ampere-hour integration calculations completed within one hour, if the ampere-hour integration period is 1 millisecond, then K=3600s/1ms=3600000;

Total_In_Ah _(k) — historical charging ampere-hour integral value at the current moment

Total_In_Ah _(k-1) — the historical charge and discharge ampere-hour integration value of the last historical charge and discharge ampere-hour integration

Total_Ah_In—historical charging AhIn

Total_Ah_In0—the initial value of historical charging AhIn0

Total_Out_Ah _(k) — historical discharge ampere-hour integral value at the current moment

Total_Out_Ah _(k-1) — the historical discharge ampere-hour integration value of the last historical charge and discharge ampere-hour integration

Total_Ah_Out—Historical discharge Ah

Total_Ah_Out0—the initial value of historical discharge ampere hours;

4. If the current of the battery pack is zero, start timing and judge the resting time of the battery, correct the open-circuit voltage of the SOC, and estimate the remaining capacity SOCv of the battery pack based on the voltage data, as follows:

When the battery resting time reaches 120 seconds, the voltage of each cell of the energy storage battery pack is judged. When a single battery falls into the high or low power range, the SOCv of the battery pack is estimated according to the temperature of the battery and the voltage of the single cell. The following table shows the corresponding relationship between the open circuit voltage and SOC of a certain brand of lithium iron phosphate single battery at different temperatures:

SOC room temperature 60℃ 0°C 100% 3.406V 3.381V 3.371V 90% 3.379V 3.335V 3.335V 80% 3.336V 3.334V 3.332V 70% 3.335V 3.308V 3.305V 60% 3.309V 3.302V 3.292V 50% 3.297V 3.301V 3.289V 40% 3.294V 3.290V 3.286V 30% 3.270V 3.259V 3.268V 20% 3.237V 3.231V 3.234V 10% 3208V 3.198V 3.206V 0% 2.774V 2.768V 2.747V

The open-circuit voltage of a single battery refers to the voltage after the ohmic voltage drop and polarization voltage are removed from the external voltage of the battery. The method and device approach the open-circuit voltage of the battery through the external voltage after the battery has been left standing for a period of time.

Moreover, the open-circuit voltage of the battery and the SOC of the single battery, especially the lithium-ion single battery, have a relatively linear correspondence in the high interval and the low interval of the charging interval. In the present invention, the high charge interval is set at 90%-100%, and the low charge interval is set at 0%-10%.

In addition, the SOC of the battery pack is different from the SOC of the single battery. In the high-charge interval, in order to prevent overcharged cells in the battery pack, the SOC of the battery pack should be corrected to the SOC corresponding to the highest cell voltage; in the low-charge interval, in order to prevent over-discharged cells in the battery pack , the SOC of the battery pack should be corrected to the SOC corresponding to the lowest cell voltage. The specific correction formula is as follows:

SOCv=90%+(Vmax-Vsoc90%)/[(Vsoc100%-Vsoc90%)/10]

Or SOCv=(Vmin-Vsoc0%)/[(Vsoc10%-Vsoc0%)/10]

Vmax—the highest monomer voltage

Vmin—minimum monomer voltage

Vsoc100% - 100% SOC corresponding to the monomer voltage

Vsoc90% - 90% SOC corresponding to the monomer voltage

Vsoc10% - 10% SOC corresponding to the monomer voltage

Vsoc0% - 0% SOC corresponding to the monomer voltage

5. Under normal circumstances, the SOC of the battery pack is the SOCi obtained by integrating the current ampere-hour. Since there is a certain error in the current measurement, the ampere-hour integral operation will continuously accumulate this error. After the energy storage battery has undergone multiple charge-discharge cycles, The error caused by the ampere-hour integration makes the SOC estimation result seriously distorted. Therefore, under the condition that the open circuit voltage correction is satisfied, setting the open circuit voltage correction result SOCv as the SOC of the energy storage battery pack can effectively eliminate the cumulative error caused by the ampere-hour integration. In this application, when the difference between SOCv and SOCi is greater than 2%, SOCv is set as the SOC of the energy storage battery pack. At the same time, assign SOCv to SOC0 as the initial value of the new remaining capacity of the battery pack, and clear the ampere-hour integral value Ah _(k) at the current moment to participate in the ampere-hour integral calculation of the next cycle.

6. Periodically store the SOC and historical charge and discharge ampere hours in the fixed physical address of the non-volatile memory. Every time the energy storage system is powered on, read the stored SOC and historical charge and discharge ampere hours, and perform the following assignment operations:

SOC0=SOC

Total_Ah_In0=Total_Ah_In

Total_Ah_Out0=Total_Ah_Out

Through the above operations, the continuity of the estimation of the remaining capacity of the energy storage battery can be guaranteed, that is, the remaining capacity data of the energy storage battery will not be lost due to maintenance of the energy storage system or unexpected power failure.

Figure 2 is a schematic structural diagram of the device for estimating the remaining capacity of the energy storage battery in this application. The device for estimating the remaining capacity of the energy storage battery in this application includes the following parts:

1. Unit voltage and temperature acquisition unit, including dedicated battery management chip LT6802-2, surface-mounted thermistor, 8-bit single-chip MCU1, and CAN communication interface.

The LT6802-2 described above can complete the detection of 12 single cell voltages and two-way temperature at most. According to the number of single cells connected in series in the energy storage battery pack, the number of single cell voltage and temperature acquisition units can be flexibly configured. The body voltage and temperature acquisition part shares a CAN bus with the battery information calculation part for data communication, which can realize the single voltage and temperature detection of more single cells.

The MCU1 controls the start and stop of the LT6802-2 voltage and temperature detection through SPI communication, reads the voltage and temperature detection results, and uploads the detection results to the battery information operation part through the CAN bus.

The thermistor is a surface mount package and is fixed on the pole of the battery.

2. The current acquisition part of the battery pack includes a bidirectional Hall current sensor, a current signal conditioning circuit, and an 8-bit single-chip microcomputer MCU2.

As shown in Figure 3, the bidirectional Hall current sensor is connected in series to the general positive terminal of the battery pack, and outputs an analog voltage to the direction judgment part of the current signal conditioning circuit. When charging, the bidirectional Hall current sensor outputs a positive analog voltage, which is input to the AD port of MCU2 through the filter part for analog-to-digital conversion, and the current direction signal is high level, which is read by the corresponding IO port of MCU2; The current sensor outputs a negative analog voltage, which becomes a positive voltage after the inverting part, and is input to the AD port of MCU2 through the filter part for analog-to-digital conversion, and the current direction signal is low level, which is read by the corresponding IO port of MCU2.

MCU2 converts the above-mentioned digital quantities after AD conversion, calculates the current value of the battery pack, and accumulates it, and periodically transmits the current value and the current accumulation value to the battery information operation part through the SCI bus.

3. The battery information computing department, including 16 single-chip MCU3 and CAN communication interface.

The MCU3 performs data communication with at least one cell voltage and temperature acquisition unit through the CAN bus, receives the cell voltage and temperature data uploaded by the cell voltage and temperature acquisition unit, and performs SOC estimation.

The read and write operation of FM3164 in the battery information storage part is controlled through the IIC bus. After SOC estimation and historical charge and discharge ampere hours are accumulated, the SOC and historical charge and discharge ampere hours are stored and read when the energy storage system is powered on next time. Get the initial information of SOC and historical charging and discharging ampere hours.

For energy storage projects, due to the huge cost of energy storage batteries and the long service life of the batteries, the actual capacity of the batteries will decline significantly in the middle and late stages of system operation. If the Cnom in the remaining capacity estimation formula still adopts the factory value of the battery, the SOC estimation result will have a large error. According to the historical charging and discharging ampere-hour data recorded in the system, consulting the relevant battery aging curve can provide a reference for the recalibration of the rated capacity.

The applicant of the present invention has explained and described the embodiment of the present invention in detail in conjunction with the accompanying drawings, but those skilled in the art should understand that the above embodiment is only a preferred embodiment of the present invention, and the detailed description is only to help readers better To understand the spirit of the present invention rather than limit the protection scope of the present invention, on the contrary, any improvement or modification made based on the spirit of the present invention shall fall within the protection scope of the present invention.

Claims (11)

1. A method for estimating the remaining capacity of an energy storage battery. The estimation method measures the voltage of a battery cell, the temperature of a battery, and the current parameters of a battery pack in series, and adopts the method of combining the ampere-hour integral of the current with the correction of the open circuit voltage of the cell. Estimate the remaining capacity SOCi of the battery pack based on the battery pack current data and the remaining capacity SOCv based on the battery pack cell voltage data, and use one of the SOCi and SOCv to set the remaining capacity SOC of the battery pack; , accumulating historical charging and discharging ampere hours, and regularly inputting historical charging and discharging ampere hours and remaining capacity SOC to the memory for storage; it is characterized in that the estimation method specifically includes the following steps: (1) Read the SOC initial value of the remaining capacity of the battery pack in the memory, and the initial value of the historical charging and discharging ampere hours; (2) Obtain corresponding voltage data, temperature data, and current data by measuring the battery cell voltage, battery temperature, and current parameters of the series battery pack; (3) By accumulating the current data, the current of the battery pack is integrated in ampere hours, and the remaining capacity SOCi of the battery pack based on the current data of the battery pack is calculated, and the SOCi is set as the remaining capacity SOC of the battery pack. Discharge ampere hours; (4) Measure the resting time of the energy storage battery. When the resting time reaches the desired time, according to the cell voltage and battery temperature of the energy storage battery, the remaining capacity SOCv of the battery pack based on the battery cell voltage data is obtained; 4.1 Judging whether the battery resting time has reached the expected time value; 4.2 When the standing time reaches the expected time value, judge whether the maximum battery voltage is in the high battery range or whether the minimum battery voltage is in the low battery range; 4.3 If the two conditions in 4.2 are met at the same time, then estimate the SOCv according to the corresponding relationship between the battery open circuit voltage and SOC at different temperatures; (5) judge the difference between SOCv and SOCi, when the difference between the two is greater than the set threshold value, set SOCv as the SOC of the battery pack; (6) Periodically write the historical charging and discharging ampere hours of the energy storage battery pack and the remaining capacity SOC of the battery pack into the non-volatile memory. 2. The method for estimating the remaining capacity of an energy storage battery according to claim 1, wherein calculating the SOCi comprises the following steps: 2.1 Judge the current direction of the battery pack. If the current is positive, it means that the energy storage battery is charging, and the ampere-hour integration result increases. If the current is negative, it means that the energy storage battery is discharging, and the ampere-hour integration result decreases; 2.2 Periodically execute the ampere-hour integral operation of the battery pack current, and set the ampere-hour integral operation period to 1 millisecond: Ah _(k) = Ah _(k-1) +I _k SOCi＝SOC0+Ah _(k) /(K*Cnom) Among them, Ah _(k) : the ampere-hour integral value at the current moment; Ah _(k-1) : the ampere-hour integral value obtained during the last ampere-hour integral operation; I _k : the current current value, when the energy storage battery is charged, I _k is Positive, I _k is negative during discharge; SOCi: remaining capacity of the battery pack based on the current data of the battery pack; SOC0: initial value of SOC of the remaining capacity of the battery pack; Cnom: rated battery capacity; The number of time-integrated operations, when the ampere-hour integration period is 1 millisecond, then K=3600s/1ms=3600000; 2.3 Periodically perform historical charging and discharging ampere-hour accumulation. The historical charging and discharging ampere-hour represents the total ampere-hours of charging and discharging of the energy storage battery since the first operation of the energy storage system: When the energy storage battery is charging: Total_In_Ah _(k) = Total_In_Ah _(k-1) + I _k Total_Ah_In＝Total_Ah_In0+Total_In_Ah _(k) /K When the energy storage battery is discharged: Total_Out_Ah _(k) = Total_Out_Ah _(k-1) + I _k Total_Ah_Out＝Total_Ah_Out0+Total_Out_Ah _(k) /K Among them, Total_In_Ah _(k) : the historical charging ampere-hour integral value at the current moment; Total_In_Ah _(k-1) : the historical charging ampere-hour integral value of the last historical charging and discharging ampere-hour integration; Total_Ah_In: historical charging ampere-hour; Total_Ah_In0: The initial value of historical charging ampere-hour; Total_Out_Ah _(k) : the historical discharge ampere-hour integral value at the current moment; Total_Out_Ah _(k-1) : the historical discharge ampere-hour integral value of the last historical charge-discharge ampere-hour integration; Total_Ah_Out: historical discharge Ah; Total_Ah_Out0: Initial value of historical discharge Ah; K: Same as the definition of K in step 3.2. 3. The method for estimating the remaining capacity of an energy storage battery according to claim 2, characterized in that: The expected time value is 120 seconds; The high battery interval and the low battery interval correspond to 90%-100% and 0%-10% of the SOC respectively. 4. The method for estimating the remaining capacity of an energy storage battery according to claim 1, characterized in that: In 4.3 of step (4), in the case of conforming to the open circuit voltage correction, if the highest cell voltage falls into the high-power range, the SOC value corresponding to the highest cell voltage is used as the SOCv of the battery pack; if the lowest cell voltage If it falls into the low battery range, the SOC value corresponding to the lowest cell voltage is used as the SOCv of the battery pack. 5. The method for estimating the remaining capacity of an energy storage battery according to claim 1, characterized in that: When the difference between SOCv and SOCi is greater than 2%, set SOCv as the new SOC value of the battery pack. 6. A device for estimating the remaining capacity of an energy storage battery based on the remaining capacity estimating method according to any one of the preceding claims, comprising: The cell voltage and temperature acquisition part measures the battery cell voltage data and temperature data, and transmits the voltage and temperature data to the battery information computing part through the CAN bus; The battery pack current acquisition part measures the current data of the battery pack and transmits it to the battery information calculation part through the SCI bus; The battery information calculation unit receives the cell voltage data, temperature data, and battery pack current data, estimates SOCi and SOCv, and sets one of the SOCi and SOCv as the SOC of the battery pack, and accumulates historical charging and discharging ampere hours, Control the reading and writing of the battery information storage unit; The battery information storage unit stores the SOC of the battery pack and historical charging and discharging ampere hours in real time. 7. The device for estimating the remaining capacity of an energy storage battery according to claim 6, characterized in that: The monomer voltage and temperature acquisition part mainly includes LT6802-2 battery management chip, surface-mounted thermistor, MCU1 for reading monomer voltage and temperature data, and CAN communication interface; LT6802-2 transmits the measured cell voltage and the temperature data measured by the surface mount thermistor to the MCU1 through the SPI bus; MCU1 uploads the single voltage and temperature data to the battery information computing department through CAN communication; Wherein, the surface-mounted thermistor is fixed at the pole of the battery. 8. The device for estimating the remaining capacity of an energy storage battery according to claim 6, characterized in that: The battery pack current acquisition unit includes a bidirectional Hall current sensor, a current signal conditioning circuit, and a current signal reading processor MCU2; The bidirectional Hall current sensor is connected in series with the total positive terminal of the battery pack, and can output bidirectional analog voltage according to different current directions; The current signal conditioning circuit judges the direction of the analog voltage output by the bidirectional Hall current sensor, outputs the direction signal to the current signal reading processor MCU2, filters the positive analog voltage output by the bidirectional Hall current sensor, and then connects it to the current signal Read the processor MCU2, the negative analog voltage is reversed and filtered, then connected to the current signal to read the processor MCU2; The current signal reading processor MCU2 reads the direction signal output by the current signal conditioning circuit, judges the current direction, and performs AD conversion on the analog voltage output by the bidirectional Hall current sensor, calculates the current value, and accumulates the battery current value in real time. Periodically transmit the current value and the accumulated result of the current value to the processor MCU3 of the battery information operation part through the SCI bus. After each current accumulation result is transmitted to the processor MCU3 of the battery information operation part, the current signal reads the The current accumulation result is cleared. 9. The device for estimating the remaining capacity of an energy storage battery according to claim 6, characterized in that: The battery information operation unit includes a battery information operation processor MCU3 and a CAN communication interface; The processor MCU3 of the battery information operation part receives the cell voltage and temperature data uploaded by the cell voltage and temperature acquisition part, the current value and the current accumulation value uploaded by the battery pack current acquisition part, and estimates the SOCi of the battery pack by accumulating the current data ; Judging the standing time, estimating the SOCv of the battery pack according to the voltage and temperature of the cells, and finally setting one of the SOCi and SOCv as the SOC of the battery pack. 10. The device for estimating the remaining capacity of an energy storage battery according to claim 9, characterized in that: said battery information calculation unit, while performing SOC estimation, accumulates historical charging and discharging ampere hours, and calculates said The historical charging and discharging ampere hours and SOC are written into the battery information storage unit. 11. The device for estimating the remaining capacity of an energy storage battery according to claim 6, characterized in that: The battery information storage unit is composed of a non-volatile memory with a model number of FM3164 and its peripheral circuits; The processor MCU3 of the battery information calculation unit performs read and write operations on the above-mentioned non-volatile memory through the IIC bus.