CN117406096A

CN117406096A - Method and device for updating voltage value of lithium iron phosphate battery SOC correction point

Info

Publication number: CN117406096A
Application number: CN202311400383.7A
Authority: CN
Inventors: 李建杰; 易行云; 陈斌斌
Original assignee: Xinwangda Power Technology Co ltd
Current assignee: Xinwangda Power Technology Co ltd
Priority date: 2023-10-26
Filing date: 2023-10-26
Publication date: 2024-01-16

Abstract

The invention discloses a voltage value updating method and a device of an SOC correction point of a lithium iron phosphate battery, which are characterized in that the maximum first voltage corresponding to each integral battery charge state variable is obtained based on the first voltage of each single core in the lithium iron phosphate battery, and the first differential pressure of the default voltage corresponding to each maximum first voltage and the integral battery charge state variable is calculated to obtain the maximum first differential pressure; when the maximum first differential pressure is determined to be larger than a preset differential pressure threshold value, calculating a second differential pressure of each maximum first voltage and the standby voltage corresponding to each integral battery charge state variable to obtain a maximum second differential pressure; when the maximum second differential pressure is not larger than the preset differential pressure threshold value, taking the maximum first voltage corresponding to each integral battery charge state variable as a default voltage; compared with the prior art, the technical scheme of the invention can realize the update of the voltage value of the SOC correction point of the lithium iron phosphate battery, and simultaneously avoid the problem of poor applicability of the correction point caused by inconsistent battery cells.

Description

Method and device for updating voltage value of lithium iron phosphate battery SOC correction point

Technical Field

The invention relates to the technical field of battery management systems, in particular to a voltage value updating method and device of an SOC correction point of a lithium iron phosphate battery.

Background

The SOC estimation of the power battery is one of the core functions of the battery management system, and the accurate SOC estimation has important significance in ensuring the safe and reliable work of the power battery, improving the high-efficiency utilization of stored electric energy and power, optimizing energy management and safety management, preventing the overcharge and overdischarge of the power battery, ensuring the long-service-life operation of the power battery and the like; however, the power battery has the characteristics of fewer measurable parameters, characteristic coupling, nonlinearity, strong time variability and the like, and the power battery state estimation with high accuracy and strong robustness faces great challenges for the application of the electric automobile and the requirements of full working conditions, wide temperature range and the like, and is always a difficult point of technical attack of the industry and a front-edge hot spot of international academic research; in particular, for a lithium iron phosphate battery, due to the platfonn of an OCV curve, great difficulty is brought to accurate estimation of the SOC, a point capable of carrying out SOC correction is found, and the accumulated SOC error caused by long-term operation in a platfonn period is particularly important to be eliminated.

Currently, there are two main methods for correcting SOC errors of lithium iron phosphate batteries: one is to perform OCV correction in a low SOC region, i.e., a region where the OCV curve slope is large; one is to correct the SOC value by the charging end according to the correspondence between the voltage value and the SOC, that is, the charging amount is corrected to the extent within the correction range, that is, the full charge is corrected to 100%.

The first mode requires a more severe condition, the battery needs to be discharged to a lower SOC state, and then the battery is kept stand for a long time enough, and the condition is not met in the actual application process of the vehicle; the scene required by the second mode has higher frequency in practical application, so that the scene is more commonly used; however, because the correction mode mainly includes setting a set of fixed voltage and SOC corresponding points in the BMS, when the consistency of the battery cells in the battery pack is poor or the battery ages, the corresponding relationship will lose accuracy, so that the method cannot well eliminate errors.

Disclosure of Invention

The invention aims to solve the technical problems that: the voltage value updating method and the device for the SOC correction point of the lithium iron phosphate battery are provided, the voltage value of the SOC correction point of the lithium iron phosphate battery is updated, and meanwhile the problem of poor applicability of the correction point caused by inconsistent battery cells is avoided.

In order to solve the technical problems, the invention provides a voltage value updating method of an SOC correction point of a lithium iron phosphate battery, which comprises the following steps:

when it is determined that a lithium iron phosphate battery enters a charging state and the temperature of the lithium iron phosphate battery is greater than a preset temperature threshold, acquiring a first voltage of each single core in the lithium iron phosphate battery under each integral battery charge state variable in a preset integral battery charge state variable range, and acquiring a maximum first voltage corresponding to each integral battery charge state variable based on the first voltage;

Selecting a default voltage corresponding to each integrated battery charge state variable, and calculating a first differential pressure between each maximum first voltage and the corresponding default voltage to obtain a maximum first differential pressure in all first differential pressures;

when the maximum first differential pressure is determined to be larger than a preset differential pressure threshold, acquiring standby voltage corresponding to each integral battery charge state variable, and calculating second differential pressure of each maximum first voltage and the corresponding standby voltage to obtain the maximum second differential pressure in all second differential pressures;

and when the maximum second differential pressure is not larger than the preset differential pressure threshold, taking the maximum first voltage corresponding to each integral battery charge state variable as the default voltage corresponding to each integral battery charge state variable.

In one possible implementation manner, under each integrated battery charge state variable within a preset integrated battery charge state variable range, a first voltage of each single core in the lithium iron phosphate battery is obtained, and based on the first voltage, a maximum first voltage corresponding to each integrated battery charge state variable is obtained, which specifically includes:

acquiring a default voltage sequence of the lithium iron phosphate battery, and simultaneously acquiring an integral battery charge state variable of the lithium iron phosphate battery;

Judging whether the integral battery charge state variable is the maximum integral battery charge state variable within a preset integral battery charge state variable range, if not, acquiring first voltage of each single core of the lithium iron phosphate battery under the integral battery charge state variable, and acquiring the maximum first voltage corresponding to the integral battery charge state variable based on a plurality of first voltages;

after the maximum first voltage corresponding to the integral battery charge state variable is obtained, carrying out left translation processing on the default voltage sequence, deleting a first default voltage sequence variable in the default voltage sequence, and placing the maximum first voltage at the last position of the default voltage sequence as a last default voltage sequence variable of the default voltage sequence;

acquiring a current integral battery charge state variable again, taking the current integral battery charge state variable as the integral battery charge state variable when judging that the current integral battery charge state variable and the integral battery charge state variable change, and judging whether the integral battery charge state variable is the maximum integral battery charge state variable within a preset integral battery charge state variable range again;

Acquiring a current default voltage sequence until the integral battery charge state variable is judged to be the maximum integral battery charge state variable within a preset integral battery charge state variable range and the current integral battery charge state variable and the integral battery charge state variable are unchanged;

and obtaining the maximum first voltage corresponding to each integrated battery charge state variable based on the current default voltage sequence.

In one possible implementation manner, before selecting the default voltage corresponding to each integrated battery charge state variable, the method further includes:

selecting a plurality of first single battery cells, after confirming that the first single battery cells are in an empty state, placing the plurality of first single battery cells in an environment with a first preset temperature for standing treatment, respectively charging the plurality of first single battery cells, and recording voltage data corresponding to each first integral battery charge state variable of each first single battery cell in a preset integral battery charge state variable range in the charging process;

averaging all voltage data corresponding to each first integrated battery charge state variable to obtain average voltage data, and taking the average voltage data as a first default voltage corresponding to each first integrated battery charge state variable at the first preset temperature;

Selecting a plurality of second single battery cells, after confirming that the second single battery cells are in an empty state, placing the second single battery cells in an environment with a second preset temperature for standing treatment, respectively charging the second single battery cells, and recording voltage data corresponding to each second integral battery charge state variable of each second single battery cell in a preset integral battery charge state variable range in the charging process;

carrying out averaging treatment on all voltage data corresponding to each second integral battery charge state variable to obtain average voltage data, and taking the average voltage data as a second default voltage corresponding to each second integral battery charge state variable at the second preset temperature;

selecting a plurality of third single battery cells, after confirming that the third single battery cells are in an empty state, placing the third single battery cells in an environment with a second preset temperature for standing treatment, respectively charging the third single battery cells, and recording voltage data corresponding to each third integrated battery charge state variable of each third sample battery in a preset integrated battery charge state variable range in the charging process;

And carrying out averaging treatment on all voltage data corresponding to each third integrated battery charge state variable to obtain average voltage data, and taking the average voltage data as a third default voltage corresponding to each third integrated battery charge state variable at the third preset temperature.

The invention provides a voltage value updating method of an SOC correction point of a lithium iron phosphate battery, which further comprises the following steps:

and acquiring a first battery temperature corresponding to each integral battery charge state variable of the lithium iron phosphate battery in a preset integral battery charge state variable range, and acquiring the first battery temperatures corresponding to a plurality of integral battery charge state variables.

In one possible implementation manner, selecting the default voltage corresponding to each integrated battery charge state variable further includes:

acquiring the first battery temperature corresponding to each integrated battery charge state variable to obtain a plurality of first battery temperatures, and calculating an average value of the plurality of first battery temperatures to obtain a first battery temperature average value;

and determining a preset temperature corresponding to each integral battery charge state variable according to the first battery temperature average value, and selecting a default voltage corresponding to each integral battery charge state variable based on the preset temperature.

and when the maximum second differential pressure is determined to be larger than the preset differential pressure threshold, taking the maximum first voltage corresponding to each integrated battery charge state variable as the standby voltage corresponding to each integrated battery charge state variable.

and when the maximum first differential pressure is not larger than a preset differential pressure threshold, taking the maximum first voltage corresponding to each integral battery charge state variable as the default voltage corresponding to each integral battery charge state variable.

The invention also provides a voltage value updating device of the lithium iron phosphate battery SOC correction point, which comprises the following components: the device comprises a first voltage acquisition module, a first verification module, a second verification module and a first default voltage updating module;

the first voltage obtaining module is used for obtaining a first voltage of each single core of the lithium iron phosphate battery under each integral battery charge state variable in a preset integral battery charge state variable range when the lithium iron phosphate battery is determined to enter a charge state and the temperature of the lithium iron phosphate battery is greater than a preset temperature threshold value, and obtaining a maximum first voltage corresponding to each integral battery charge state variable based on the first voltage;

The first verification module is used for selecting a default voltage corresponding to each integrated battery charge state variable, and calculating a first differential pressure between each maximum first voltage and the corresponding default voltage to obtain a maximum first differential pressure in all first differential pressures;

the second verification module is used for acquiring standby voltage corresponding to each integral battery charge state variable when the maximum first differential pressure is determined to be greater than a preset differential pressure threshold value, and calculating second differential pressures of each maximum first voltage and the corresponding standby voltage to obtain the maximum second differential pressure in all the second differential pressures;

and the first default voltage updating module is configured to, when it is determined that the maximum second differential pressure is not greater than the preset differential pressure threshold, use the maximum first voltage corresponding to each integrated battery charge state variable as the default voltage corresponding to each integrated battery charge state variable.

In one possible implementation manner, the first voltage obtaining module is configured to obtain, in each integrated battery state of charge variable within a preset integrated battery state of charge variable range, a first voltage of each single core in the lithium iron phosphate battery, and obtain, based on the first voltage, a maximum first voltage corresponding to each integrated battery state of charge variable, where the maximum first voltage specifically includes:

In one possible implementation manner, before the first verification module is configured to select the default voltage corresponding to each integrated battery charge state variable, the first verification module further includes:

The invention provides a voltage value updating device of an SOC correction point of a lithium iron phosphate battery, which further comprises: a first battery temperature acquisition module;

the first battery temperature obtaining module is configured to obtain a first battery temperature corresponding to each integrated battery charge state variable of the lithium iron phosphate battery within a preset integrated battery charge state variable range, and obtain the first battery temperatures corresponding to a plurality of integrated battery charge state variables.

In one possible implementation manner, the first verification module is configured to select a default voltage corresponding to each integrated battery charge state variable, and further includes:

The invention provides a voltage value updating device of an SOC correction point of a lithium iron phosphate battery, which further comprises: a standby voltage update module;

and the standby voltage updating module is further configured to, when it is determined that the maximum second differential pressure is greater than the preset differential pressure threshold, use the maximum first voltage corresponding to each integrated battery charge state variable as the standby voltage corresponding to each integrated battery charge state variable.

The invention provides a voltage value updating device of an SOC correction point of a lithium iron phosphate battery, which further comprises: a second default voltage update module;

and the second default voltage updating module is configured to, when it is determined that the maximum first differential pressure is not greater than a preset differential pressure threshold, use the maximum first voltage corresponding to each integrated battery charge state variable as the default voltage corresponding to each integrated battery charge state variable.

The invention also provides a terminal device, which comprises a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, wherein the voltage value updating method of the lithium iron phosphate battery SOC correction point is realized when the processor executes the computer program.

The invention also provides a computer readable storage medium, which comprises a stored computer program, wherein the computer program is used for controlling equipment where the computer readable storage medium is located to execute the voltage value updating method of the lithium iron phosphate battery SOC correction point according to any one of the above steps when running.

Compared with the prior art, the voltage value updating method and device for the SOC correction point of the lithium iron phosphate battery have the following beneficial effects:

when the lithium iron phosphate battery is determined to enter a charging state and the temperature of the lithium iron phosphate battery is larger than a preset temperature threshold value, acquiring a first voltage of each single core in the lithium iron phosphate battery under each integral battery charge state variable in a preset integral battery charge state variable range, and acquiring a maximum first voltage corresponding to each integral battery charge state variable based on the first voltage; selecting a default voltage corresponding to each integrated battery charge state variable, and calculating a first differential pressure between each maximum first voltage and the corresponding default voltage to obtain the maximum first differential pressure in all the first differential pressures; when the maximum first differential pressure is determined to be greater than a preset differential pressure threshold, acquiring standby voltage corresponding to each integrated battery charge state variable, and calculating second differential pressure of each maximum first voltage and the corresponding standby voltage to obtain the maximum second differential pressure in all second differential pressures; when the maximum second differential pressure is not larger than the preset differential pressure threshold value, taking the maximum first voltage corresponding to each integral battery charge state variable as the default voltage corresponding to each integral battery charge state variable; compared with the prior art, the technical scheme of the invention can effectively solve the problem faced when the voltage value of the current correction point is fixed by updating the voltage value of the SOC correction point of the lithium iron phosphate battery, so that the accuracy of correcting the SOC error subsequently is improved based on the updated voltage value.

Drawings

FIG. 1 is a schematic flow chart of an embodiment of a method for updating a voltage value of an SOC correction point of a lithium iron phosphate battery according to the present invention;

FIG. 2 is a schematic diagram of an embodiment of a voltage value updating device for an SOC correction point of a lithium iron phosphate battery according to the present invention;

FIG. 3 is a schematic diagram of a second table variable U16_ChgVvsSOC_Def for one embodiment provided by the present invention;

FIG. 4 is a schematic diagram of a charging process temporary table variable U16_ChgVvsSOC_temp for one embodiment provided herein;

FIG. 5 is a schematic diagram of a default voltage sequence for one embodiment provided by the present invention;

FIG. 6 is a schematic diagram of a default voltage sequence movement for one embodiment provided by the present invention;

fig. 7 is a charging map representation of one embodiment provided by the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Referring to fig. 1, fig. 1 is a flow chart of an embodiment of a method for updating a voltage value of an SOC correction point of a lithium iron phosphate battery according to the present invention, as shown in fig. 1, the method includes steps 101 to 104, specifically as follows:

step 101: when it is determined that a lithium iron phosphate battery enters a charging state and the temperature of the lithium iron phosphate battery is larger than a preset temperature threshold, acquiring a first voltage of each single core in the lithium iron phosphate battery under each integral battery charge state variable in a preset integral battery charge state variable range, and acquiring a maximum first voltage corresponding to each integral battery charge state variable based on the first voltage.

In one embodiment, a first table variable u16_chgvvcsoc_ Upt is further set in the BMS program of the battery management system, and the data type is uint16, the size is 3×11, and is used for storing the voltage point for correcting the battery state of charge variable in actual operation, and the variable table is also used for storing the new correction voltage point obtained by self-learning of the subsequent program.

In one embodiment, a second table variable u16_chgvvsosoc_def is set in the BMS program of the battery management system, the data type is uint16, the size is 3×11, and the data is used for storing measured default relationship data, each row represents a temperature point (0 ℃, 15 ℃, 25 ℃) and each column represents a voltage value corresponding to the SOC point (from 90% to 100%); as shown in fig. 3, fig. 3 is a schematic diagram of a second table variable u16_chgvvsosc_def.

In an embodiment, whether the battery management system BMS is powered on for the first time is determined, if yes, default data stored by the u16_chgvvsosc_def is given to a new variable u16_chgvvsosc_ Upt, so that the new variable u16_chgvvsosc_ Upt is used in an actual running process.

In an embodiment, when it is determined that the temperature of the lithium iron phosphate battery is not greater than a preset temperature threshold, the program is run and online learning of new data is not performed. Preferably, the preset temperature threshold is 0 ℃.

In one embodiment, a temporary charging process table variable U16_chgvvssoc_temp is set in a BMS program of the battery management system, and the data type is uint16, the size is 3×11, and the temporary charging process table variable U16_chgvvssoc_temp is used for recording the data of the voltage, the current and the temperature of each single battery cell of the lithium iron phosphate battery in the charging process; as shown in fig. 4, fig. 4 is a schematic diagram of a charging process temporary table variable u16_chgvvsocsoc_temp.

In an embodiment, when obtaining a first voltage of each single core of the lithium iron phosphate battery under each integrated battery state-of-charge variable within a preset integrated battery state-of-charge variable range, and obtaining a maximum first voltage corresponding to each integrated battery state-of-charge variable based on the first voltage, the method specifically includes steps S11-S16.

S11: and acquiring a default voltage sequence of the lithium iron phosphate battery, and simultaneously acquiring an integral battery charge state variable of the lithium iron phosphate battery.

In step S11, the charging process temporary table variable u16_chgvvssoc_temp is obtained, and the voltage values stored in the charging process temporary table variable u16_chgvvssoc_temp are ordered to obtain a default voltage sequence of the lithium iron phosphate battery; based on the value variable of 3×11, the length of the default voltage sequence is 11, as shown in fig. 5, and fig. 5 is a schematic diagram of the default voltage sequence.

In step S11, an initial value of an integrated battery state-of-charge variable is obtained, the initial value of the integrated battery state-of-charge variable is substituted into an integrated battery state-of-charge variable calculation formula, and an integrated battery state-of-charge variable of the lithium iron phosphate battery is calculated, wherein the integrated battery state-of-charge variable calculation formula is as follows:

wherein SOC is ₀ For integrating the initial value of the charge state variable of the battery, for storing the SOC at the last power-down _AH When the power is on, the memory is read to obtain the initial value; i is current; q_max is the nominal capacity of the battery at normal temperature.

S12: judging whether the integral battery charge state variable is the maximum integral battery charge state variable within a preset integral battery charge state variable range, if not, acquiring the first voltage of each single core of the lithium iron phosphate battery under the integral battery charge state variable, and acquiring the maximum first voltage corresponding to the integral battery charge state variable based on a plurality of first voltages.

In step S12, the maximum integrated battery state of charge variable is 100%, and when it is determined that the integrated battery state of charge variable is not the maximum integrated battery state of charge variable within the preset integrated battery state of charge variable range, the lithium iron phosphate battery is considered to be still in a charged state.

In step S12, since the number of single-core monomers in the common lithium iron phosphate battery is generally about 2 to 20, based on the currently calculated integrated battery charge state variable, the first voltage of each single-core monomer in the lithium iron phosphate battery in the integrated battery charge state variable is obtained, and based on the plurality of first voltages, the maximum first voltage corresponding to the integrated battery charge state variable is obtained, that is, the maximum voltage of the single-core monomer in the lithium iron phosphate battery in the integrated battery charge state variable is determined.

In step S12, a first current of each single core of the lithium iron phosphate battery under the integrated battery charge state variable is further obtained, and a maximum first current corresponding to the integrated battery charge state variable is obtained based on the plurality of first currents.

In step S12, a first temperature of each single core of the lithium iron phosphate battery under the integrated battery charge state variable is further obtained, and based on the plurality of first temperatures, a lowest first temperature corresponding to the integrated battery charge state variable is obtained.

S13: and after the maximum first voltage corresponding to the integral battery charge state variable is obtained, carrying out left translation processing on the default voltage sequence, deleting a first default voltage sequence variable in the default voltage sequence, and placing the maximum first voltage at the last position of the default voltage sequence as a last default voltage sequence variable of the default voltage sequence.

In step S13, the movement manner of the default voltage sequence is shown in fig. 6, fig. 6 is a schematic diagram of movement of the default voltage sequence, and from the left side, the previous unit is sequentially covered with the data of the next unit, and finally the data of the last unit is covered with the new data, so as to complete the translation processing of the data.

In step S13, when it is determined that the integrated battery state of charge variable of the lithium iron phosphate battery changes by 1%, recording voltage, current and temperature data corresponding to each single cell in the lithium iron phosphate battery, acquiring a maximum first voltage, a maximum first current and a minimum first temperature corresponding to the integrated battery state of charge variable based on the voltage, current and temperature data corresponding to each single cell, storing the maximum first voltage, the maximum first current and the minimum first temperature into a temporary charging process table variable u16_chgvvsoc_temp set in the battery management system BMS program, and moving the default voltage sequence, and simultaneously moving the current, the voltage and the temperature data in the temporary charging process table variable u16_chgvvssoc_temp left by one time.

S14: and re-acquiring a current integral battery charge state variable, taking the current integral battery charge state variable as the integral battery charge state variable when judging that the current integral battery charge state variable and the integral battery charge state variable change, and re-judging whether the integral battery charge state variable is the maximum integral battery charge state variable within a preset integral battery charge state variable range.

S15: and acquiring a current default voltage sequence until the integral battery charge state variable is judged to be the maximum integral battery charge state variable in a preset integral battery charge state variable range and the current integral battery charge state variable and the integral battery charge state variable are unchanged.

S16: and obtaining the maximum first voltage corresponding to each integrated battery charge state variable based on the current default voltage sequence.

Step 102: and selecting a default voltage corresponding to each integrated battery charge state variable, and calculating a first differential pressure between each maximum first voltage and the corresponding default voltage to obtain the maximum first differential pressure in all the first differential pressures.

In an embodiment, a plurality of first single battery cells are selected, after the first single battery cells are confirmed to be in an empty state and placed in an environment with a first preset temperature for standing treatment, the plurality of first single battery cells are respectively charged, and in the charging process, voltage data corresponding to each first integrated battery charge state variable of each first single battery cell in a preset integrated battery charge state variable range are recorded.

Specifically, a plurality of first single battery cells are selected, the plurality of first single battery cells are subjected to discharge treatment at normal temperature, and the first single battery cells are determined to be in an emptying state when the voltage of the plurality of first single battery cells is cut-off voltage.

Preferably, the number of the plurality of first single battery cells is set to be 3.

Specifically, the plurality of first monomer battery cells are placed in an environment with a first preset temperature for standing for 6 hours, wherein the first preset temperature is 0 ℃.

Specifically, the charging map table is charged to soc=100%, that is, full charge, with a specified current, as shown in fig. 7, and fig. 7 shows the intention of the charging map.

Specifically, the preset integral battery state of charge variable ranges from soc=90% to 100%, and each first integral battery state of charge variable ranges from soc=90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% and 100%. During charging, voltage data of each 1% of SOC of the plurality of first single battery cells in the soc=90% -100% process are recorded respectively.

In an embodiment, all voltage data corresponding to each first integrated battery state of charge variable is averaged to obtain first average voltage data, and the first average voltage data is used as a first default voltage corresponding to each first integrated battery state of charge variable at the first preset temperature.

Specifically, voltage data of a plurality of first single battery cells under each first integral battery charge state variable is obtained, and first average voltage data is calculated for all the voltage data under each first integral battery charge state variable.

In an embodiment, a plurality of second single battery cells are selected, after the second single battery cells are confirmed to be in an empty state and placed in an environment with a second preset temperature for standing treatment, the plurality of second single battery cells are respectively charged, and in the charging process, voltage data corresponding to each second integral battery charge state variable of each second single battery cell in a preset integral battery charge state variable range are recorded.

Specifically, a plurality of second single battery cells are selected, the second single battery cells are subjected to discharge treatment at normal temperature, and the second single battery cells are determined to be in an empty state until the voltage of the second single battery cells is cut-off voltage.

Preferably, the number of the plurality of second single battery cells is set to be 3.

Specifically, the plurality of second monomer cells are placed in an environment with a second preset temperature for 6 hours, wherein the second preset temperature is 15 ℃.

Specifically, the charge map table is charged with a specified current until soc=100%, i.e., full charge.

Specifically, the preset integral battery state of charge variable ranges from soc=90% to 100%, and each second integral battery state of charge variable ranges from soc=90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% and 100%. During charging, voltage data of each 1% of SOC of the plurality of second single battery cells in the soc=90% -100% process are recorded respectively.

Preferably, each second integrated battery state of charge variable within the predetermined integrated battery state of charge variable range is the same as each first integrated battery state of charge variable within the predetermined integrated battery state of charge variable range.

In an embodiment, all the voltage data corresponding to each second integrated battery state of charge variable are averaged to obtain second average voltage data, and the second average voltage data is used as a second default voltage corresponding to each second integrated battery state of charge variable at the second preset temperature.

Specifically, second voltage data of a plurality of second single battery cells under each second integral battery charge state variable are obtained, and second average voltage data is calculated for all the voltage data under each second integral battery charge state variable.

In an embodiment, a plurality of third single battery cells are selected, after the third single battery cells are confirmed to be in an empty state and are placed in an environment with a second preset temperature for standing treatment, the third single battery cells are respectively charged, and in the charging process, voltage data corresponding to each third integrated battery charge state variable of each third sample battery in a preset integrated battery charge state variable range are recorded.

Specifically, a plurality of third single battery cells are selected, the third single battery cells are subjected to discharge treatment at normal temperature, and the third single battery cells are determined to be in an empty state when the voltage of the third single battery cells is cut-off voltage.

Preferably, the number of the plurality of third single battery cells is set to be 3.

Specifically, the plurality of third monomer cells are placed in an environment of a third preset temperature for 6 hours, wherein the second preset temperature is 25 ℃.

Specifically, the preset integral battery state of charge variable ranges from soc=90% to 100%, and each third integral battery state of charge variable ranges from soc=90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% and 100%. During charging, voltage data of each 1% of SOC of the plurality of third single battery cells in the soc=90% -100% process are recorded respectively.

Preferably, each third integrated battery state of charge variable in the preset integrated battery state of charge variable range is the same as the value of each first integrated battery state of charge variable in the preset integrated battery state of charge variable range and each second integrated battery state of charge variable in the preset integrated battery state of charge variable range, respectively.

In an embodiment, all the voltage data corresponding to the state of charge variable of each third integrated battery are averaged to obtain third average voltage data, and the third average voltage data is used as a third default voltage corresponding to the state of charge variable of each third integrated battery at the third preset temperature.

Specifically, third voltage data of a plurality of third single battery cells under each third integral battery charge state variable are obtained, and third average voltage data is calculated for all the voltage data under each third integral battery charge state variable.

In one embodiment, after obtaining the first average voltage data, the second average voltage data and the third average voltage data, an initial voltage and SOC relationship data table is obtained based on the first average voltage data, the second average voltage data and the third average voltage data, and the initial voltage and SOC relationship data table records a set of correspondence tables of voltages and SOCs at different temperatures.

Preferably, the obtained initial voltage and SOC relation data table is stored in a second table variable u16_chgvvsosc_def set inside the battery management system BMS program.

In an embodiment, a first battery temperature corresponding to each integrated battery charge state variable in a preset integrated battery charge state variable range of the lithium iron phosphate battery is obtained, and the first battery temperatures corresponding to a plurality of integrated battery charge state variables are obtained.

Specifically, based on a temporary table variable in the charging process, a first battery temperature corresponding to each integral battery charge state variable in a preset integral battery charge state variable range in the charging process of the lithium iron phosphate battery is obtained.

In an embodiment, the first battery temperature corresponding to each integrated battery charge state variable is obtained to obtain a plurality of first battery temperatures, and an average value of the plurality of first battery temperatures is calculated to obtain a first battery temperature average value; and determining a preset temperature corresponding to each integral battery charge state variable according to the first battery temperature average value, and selecting a default voltage corresponding to each integral battery charge state variable based on the preset temperature.

Specifically, after a first battery temperature average value is calculated, comparing the first battery temperature average value with a preset temperature, wherein the preset temperature comprises 0 ℃, 15 ℃ and 25 ℃; when the average value of the first battery temperature is larger than 0 ℃ but not larger than 15 ℃, determining that the preset temperature corresponding to each integral battery charge state variable is 0 ℃, and when the average value of the first battery temperature is larger than 15 ℃ but not larger than 25 ℃, determining that the preset temperature corresponding to each integral battery charge state variable is 15 ℃; and when the average value of the first battery temperature is larger than 25 ℃, determining that the preset temperature corresponding to each integrated battery charge state variable is 25 ℃.

Specifically, based on the preset temperature, selecting a default voltage corresponding to each integrated battery charge state variable from the initial voltage and SOC relation data table.

In an embodiment, after the maximum first voltage corresponding to each integrated battery charge state variable is obtained, validity of the obtained maximum first voltage corresponding to each integrated battery charge state variable is further required to be judged, a first differential pressure corresponding to each integrated battery charge state variable is calculated by subtracting the maximum first voltage corresponding to each integrated battery charge state variable from the default voltage corresponding to each integrated battery charge state variable, and the maximum first differential pressure is obtained based on all the first differential pressures.

Step 103: and when the maximum first differential pressure is determined to be greater than a preset differential pressure threshold, acquiring standby voltage corresponding to each integral battery charge state variable, and calculating second differential pressure of each maximum first voltage and the corresponding standby voltage to obtain the maximum second differential pressure in all second differential pressures.

In one embodiment, the predetermined differential pressure threshold is 5mv.

In an embodiment, when it is determined that the maximum first differential pressure is greater than a preset differential pressure threshold, the learning data is considered to be in doubt, and a standby voltage corresponding to each integrated battery charge state variable is obtained, where the standby voltage is voltage data stored in a standby variable u16_chgvvsssoc_bckup.

In an embodiment, the second differential pressure corresponding to each integrated battery state of charge variable is calculated by subtracting the maximum first voltage corresponding to each integrated battery state of charge variable from the standby voltage corresponding to each integrated battery state of charge variable, and the maximum second differential pressure is obtained based on all the second differential pressures.

Preferably, when the maximum first differential pressure is determined to be greater than a preset differential pressure threshold, whether the U8_needledVerifly is set is further determined, if not, the variable U8_needledVerifly is set, and the maximum first voltage corresponding to each integral battery charge state variable is stored into a standby variable U16_chgVvsSOC_Bckup for secondary validity determination of the acquired data next time, and meanwhile, a flag bit U8_needledVerifly is set to stop the learning.

In an embodiment, when it is determined that the maximum first differential pressure is not greater than a preset differential pressure threshold, the learning is considered to be effective, the maximum first voltage corresponding to each integrated battery charge state variable is used as the default voltage corresponding to each integrated battery charge state variable, and the default voltage corresponding to each integrated battery charge state variable is stored in a first table variable u16_chgvvssoc_ Upt, so that the learning is completed, and online updating of SOC correction points is realized.

Step 104: and when the maximum second differential pressure is not larger than the preset differential pressure threshold, taking the maximum first voltage corresponding to each integral battery charge state variable as the default voltage corresponding to each integral battery charge state variable.

In an embodiment, when it is determined that the maximum second differential pressure is not greater than the preset differential pressure threshold, the learning is considered to be effective, after the maximum first voltage corresponding to each integrated battery charge state variable is used as the default voltage corresponding to each integrated battery charge state variable, the default voltage corresponding to each integrated battery charge state variable is stored in a first table variable u16_chgvvssoc_ Upt, the learning is completed, and online updating of SOC correction points is achieved.

In an embodiment, when the maximum second differential pressure is determined to be greater than a preset differential pressure threshold, the learning data is considered to be in doubt, whether the u8_ NeedSecondVer ify is set is further determined, if not, the adjusting variable u8_ NeedSecondVer ify is set, the maximum first voltage corresponding to each integrated battery charge state variable is used as the standby voltage corresponding to each integrated battery charge state variable, and the standby voltage is stored into a standby variable u16_chgvvsssoc_bckup for next secondary validity determination of the learned data, and meanwhile, the flag bit u8_ NeedSecondVer ify is set to stop the learning.

Embodiment 2, referring to fig. 2, fig. 2 is a schematic structural diagram of an embodiment of a voltage value updating device of an SOC correction point of a lithium iron phosphate battery according to the present invention, and as shown in fig. 2, the device includes a first voltage obtaining module 201, a first verifying module 202, a second verifying module 203, and a first default voltage updating module 204, which are specifically as follows:

the first voltage obtaining module 201 is configured to obtain, when it is determined that the lithium iron phosphate battery is in a charging state and the temperature of the lithium iron phosphate battery is greater than a preset temperature threshold, a first voltage of each single core of the lithium iron phosphate battery under each integral battery charge state variable within a preset integral battery charge state variable range, and obtain a maximum first voltage corresponding to each integral battery charge state variable based on the first voltage.

The first verification module 202 is configured to select a default voltage corresponding to each integrated battery charge state variable, calculate a first differential pressure between each maximum first voltage and the corresponding default voltage, and obtain a maximum first differential pressure among all the first differential pressures.

The second verification module 203 is configured to obtain a standby voltage corresponding to each integrated battery charge state variable when the maximum first differential pressure is determined to be greater than a preset differential pressure threshold, and calculate a second differential pressure between each maximum first voltage and the corresponding standby voltage, so as to obtain a maximum second differential pressure in all the second differential pressures.

The first default voltage updating module 204 is configured to, when it is determined that the maximum second differential pressure is not greater than the preset differential pressure threshold, use the maximum first voltage corresponding to each integrated battery state of charge variable as the default voltage corresponding to each integrated battery state of charge variable.

In an embodiment, the first voltage obtaining module 201 is configured to obtain, for each integrated battery state of charge variable within a preset integrated battery state of charge variable range, a first voltage of each single core of the lithium iron phosphate battery, and obtain, based on the first voltage, a maximum first voltage corresponding to each integrated battery state of charge variable, where the maximum first voltage specifically includes: acquiring a default voltage sequence of the lithium iron phosphate battery, and simultaneously acquiring an integral battery charge state variable of the lithium iron phosphate battery; judging whether the integral battery charge state variable is the maximum integral battery charge state variable within a preset integral battery charge state variable range, if not, acquiring first voltage of each single core of the lithium iron phosphate battery under the integral battery charge state variable, and acquiring the maximum first voltage corresponding to the integral battery charge state variable based on a plurality of first voltages; after the maximum first voltage corresponding to the integral battery charge state variable is obtained, carrying out left translation processing on the default voltage sequence, deleting a first default voltage sequence variable in the default voltage sequence, and placing the maximum first voltage at the last position of the default voltage sequence as a last default voltage sequence variable of the default voltage sequence; acquiring a current integral battery charge state variable again, taking the current integral battery charge state variable as the integral battery charge state variable when judging that the current integral battery charge state variable and the integral battery charge state variable change, and judging whether the integral battery charge state variable is the maximum integral battery charge state variable within a preset integral battery charge state variable range again; acquiring a current default voltage sequence until the integral battery charge state variable is judged to be the maximum integral battery charge state variable within a preset integral battery charge state variable range and the current integral battery charge state variable and the integral battery charge state variable are unchanged; and obtaining the maximum first voltage corresponding to each integrated battery charge state variable based on the current default voltage sequence.

In one embodiment, the first verification module 202 is configured to, before selecting the default voltage corresponding to each integrated battery state of charge variable, further include: selecting a plurality of first single battery cells, after confirming that the first single battery cells are in an empty state, placing the plurality of first single battery cells in an environment with a first preset temperature for standing treatment, respectively charging the plurality of first single battery cells, and recording voltage data corresponding to each first integral battery charge state variable of each first single battery cell in a preset integral battery charge state variable range in the charging process; averaging all voltage data corresponding to each first integrated battery charge state variable to obtain average voltage data, and taking the average voltage data as a first default voltage corresponding to each first integrated battery charge state variable at the first preset temperature; selecting a plurality of second single battery cells, after confirming that the second single battery cells are in an empty state, placing the second single battery cells in an environment with a second preset temperature for standing treatment, respectively charging the second single battery cells, and recording voltage data corresponding to each second integral battery charge state variable of each second single battery cell in a preset integral battery charge state variable range in the charging process; carrying out averaging treatment on all voltage data corresponding to each second integral battery charge state variable to obtain average voltage data, and taking the average voltage data as a second default voltage corresponding to each second integral battery charge state variable at the second preset temperature; selecting a plurality of third single battery cells, after confirming that the third single battery cells are in an empty state, placing the third single battery cells in an environment with a second preset temperature for standing treatment, respectively charging the third single battery cells, and recording voltage data corresponding to each third integrated battery charge state variable of each third sample battery in a preset integrated battery charge state variable range in the charging process; and carrying out averaging treatment on all voltage data corresponding to each third integrated battery charge state variable to obtain average voltage data, and taking the average voltage data as a third default voltage corresponding to each third integrated battery charge state variable at the third preset temperature.

In an embodiment, the device for updating the voltage value of the SOC correction point of the lithium iron phosphate battery provided by the embodiment of the present invention further includes: a first battery temperature acquisition module.

In an embodiment, the first battery temperature obtaining module is configured to obtain a first battery temperature corresponding to each integrated battery charge state variable of the lithium iron phosphate battery within a preset integrated battery charge state variable range, so as to obtain the first battery temperatures corresponding to a plurality of integrated battery charge state variables.

In one embodiment, the first verification module 202 is configured to select a default voltage corresponding to each integrated battery state of charge variable, and further includes: acquiring the first battery temperature corresponding to each integrated battery charge state variable to obtain a plurality of first battery temperatures, and calculating an average value of the plurality of first battery temperatures to obtain a first battery temperature average value; and determining a preset temperature corresponding to each integral battery charge state variable according to the first battery temperature average value, and selecting a default voltage corresponding to each integral battery charge state variable based on the preset temperature.

In an embodiment, the device for updating the voltage value of the SOC correction point of the lithium iron phosphate battery provided by the embodiment of the present invention further includes: and a standby voltage updating module.

In an embodiment, the standby voltage updating module is further configured to, when it is determined that the maximum second differential pressure is greater than the preset differential pressure threshold, use the maximum first voltage corresponding to each integrated battery charge state variable as the standby voltage corresponding to each integrated battery charge state variable.

In an embodiment, the device for updating the voltage value of the SOC correction point of the lithium iron phosphate battery provided by the embodiment of the present invention further includes: and a second default voltage updating module.

In an embodiment, the second default voltage updating module is configured to, when it is determined that the maximum first differential pressure is not greater than a preset differential pressure threshold, use the maximum first voltage corresponding to each integrated battery charge state variable as the default voltage corresponding to each integrated battery charge state variable.

It will be clear to those skilled in the art that, for convenience and brevity of description, reference may be made to the corresponding process in the foregoing method embodiment for the specific working process of the above-described apparatus, which is not described in detail herein.

It should be noted that, the embodiment of the voltage value updating device of the SOC correction point of the lithium iron phosphate battery is merely illustrative, where the module described as a separate component may or may not be physically separated, and the component displayed as a module may or may not be a physical unit, may be located in one place, or may be distributed over a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

On the basis of the embodiment of the method for updating the voltage value of the lithium iron phosphate battery SOC correction point, another embodiment of the invention provides a terminal device for updating the voltage value of the lithium iron phosphate battery SOC correction point, which comprises a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, wherein the processor executes the computer program to realize the method for updating the voltage value of the lithium iron phosphate battery SOC correction point according to any embodiment of the invention.

Illustratively, in this embodiment the computer program may be partitioned into one or more modules, which are stored in the memory and executed by the processor to perform the present invention. The one or more modules may be a series of computer program instruction segments capable of performing a specific function for describing the execution of the computer program in a voltage value update terminal device of the lithium iron phosphate battery SOC correction point.

The voltage value updating terminal equipment of the lithium iron phosphate battery SOC correction point can be computing equipment such as a desktop computer, a notebook computer, a palm computer and a cloud server. The voltage value updating terminal device of the lithium iron phosphate battery SOC correction point can comprise, but is not limited to, a processor and a memory.

The processor may be a central processing unit (Central Processing Unit, CPU), other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. The general processor may be a microprocessor or any conventional processor, etc., and the processor is a control center of the terminal device for updating the voltage value of the SOC correction point of the lithium iron phosphate battery, and is connected to various parts of the terminal device by various interfaces and lines.

The memory may be used to store the computer program and/or module, and the processor may implement various functions of the terminal device for updating the voltage value of the lithium iron phosphate battery SOC correction point by running or executing the computer program and/or module stored in the memory and invoking data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function, and the like; the storage data area may store data created according to the use of the cellular phone, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, memory, plug-in hard disk, smart Media Card (SMC), secure Digital (SD) Card, flash Card (Flash Card), at least one disk storage device, flash memory device, or other volatile solid-state storage device.

On the basis of the embodiment of the method for updating the voltage value of the lithium iron phosphate battery SOC correction point, another embodiment of the invention provides a storage medium, which comprises a stored computer program, wherein when the computer program runs, equipment where the storage medium is located is controlled to execute the method for updating the voltage value of the lithium iron phosphate battery SOC correction point according to any embodiment of the invention.

In this embodiment, the storage medium is a computer-readable storage medium, and the computer program includes computer program code, where the computer program code may be in a source code form, an object code form, an executable file, or some intermediate form, and so on. The computer readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-only Memory (ROM), a random access Memory (RAM, random Access Memory), an electrical carrier wave signal, a telecommunication signal, a software distribution medium, and so forth. It should be noted that the computer readable medium contains content that can be appropriately scaled according to the requirements of jurisdictions in which such content is subject to legislation and patent practice, such as in certain jurisdictions in which such content is subject to legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals.

In summary, according to the method and the device for updating the voltage value of the SOC correction point of the lithium iron phosphate battery, when the lithium iron phosphate battery is determined to enter a charging state and the temperature of the lithium iron phosphate battery is higher than a preset temperature threshold, a first voltage of each single unit core in the lithium iron phosphate battery is obtained under each integral battery charge state variable in a preset integral battery charge state variable range, and a maximum first voltage corresponding to each integral battery charge state variable is obtained based on the first voltage; selecting a default voltage corresponding to each integrated battery charge state variable, and calculating a first differential pressure between each maximum first voltage and the corresponding default voltage to obtain a maximum first differential pressure in all first differential pressures; when the maximum first differential pressure is determined to be larger than a preset differential pressure threshold, acquiring standby voltage corresponding to each integral battery charge state variable, and calculating second differential pressure of each maximum first voltage and the corresponding standby voltage to obtain the maximum second differential pressure in all second differential pressures; when the maximum second differential pressure is not larger than the preset differential pressure threshold, taking the maximum first voltage corresponding to each integral battery charge state variable as the default voltage corresponding to each integral battery charge state variable; compared with the prior art, the technical scheme of the invention can realize the update of the voltage value of the SOC correction point of the lithium iron phosphate battery, and simultaneously avoid the problem of poor applicability of the correction point caused by inconsistent battery cells.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and substitutions can be made by those skilled in the art without departing from the technical principles of the present invention, and these modifications and substitutions should also be considered as being within the scope of the present invention.

Claims

1. The method for updating the voltage value of the SOC correction point of the lithium iron phosphate battery is characterized by comprising the following steps of:

2. The method for updating a voltage value of an SOC correction point of a lithium iron phosphate battery according to claim 1, wherein the method for updating a voltage value of an SOC correction point of a lithium iron phosphate battery is characterized by obtaining a first voltage of each single cell in the lithium iron phosphate battery under each integrated battery state of charge variable within a preset integrated battery state of charge variable range, and obtaining a maximum first voltage corresponding to each integrated battery state of charge variable based on the first voltage, and specifically includes:

3. The method for updating the voltage value of the SOC calibration point of a lithium iron phosphate battery according to claim 1, further comprising, before selecting the default voltage corresponding to each integrated battery state of charge variable:

4. The method for updating a voltage value of an SOC calibration point of a lithium iron phosphate battery according to claim 3, further comprising:

5. The method for updating a voltage value of an SOC calibration point of a lithium iron phosphate battery according to claim 4, wherein selecting a default voltage corresponding to each integrated battery state of charge variable further comprises:

6. The method for updating the voltage value of the SOC correction point of a lithium iron phosphate battery according to claim 1, further comprising:

7. The method for updating the voltage value of the SOC correction point of a lithium iron phosphate battery according to claim 1, further comprising:

8. The utility model provides a voltage value updating device of lithium iron phosphate battery SOC correction point which characterized in that includes: the device comprises a first voltage acquisition module, a first verification module, a second verification module and a first default voltage updating module;

9. A terminal device comprising a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, the processor implementing the method for updating the voltage value of the lithium iron phosphate battery SOC correction point according to any of claims 1 to 7 when the computer program is executed.

10. A computer readable storage medium, characterized in that the computer readable storage medium comprises a stored computer program, wherein the computer program when run controls a device in which the computer readable storage medium is located to perform the method for updating the voltage value of the SOC correction point of the lithium iron phosphate battery according to any one of claims 1 to 7.