CN115684966A - Lithium ion battery SOC correction method, system, equipment and medium - Google Patents

Lithium ion battery SOC correction method, system, equipment and medium Download PDF

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CN115684966A
CN115684966A CN202211128448.2A CN202211128448A CN115684966A CN 115684966 A CN115684966 A CN 115684966A CN 202211128448 A CN202211128448 A CN 202211128448A CN 115684966 A CN115684966 A CN 115684966A
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voltage
capacity
soc
target battery
battery
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陈群
胡浩
吴文贵
童天辰
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Shitu Technology Hangzhou Co ltd
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Shitu Technology Hangzhou Co ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention discloses a lithium ion battery SOC correction method, a system, equipment and a medium, wherein the lithium ion battery SOC correction method comprises the steps of obtaining the static voltage of a target battery; judging whether the static voltage is in a voltage platform area of the target battery; if the target battery is not in the voltage leveling area, correcting the current SOC of the target battery through an OCV-SOC curve of the lithium ion battery; if the target battery is located in the voltage platform area, requesting a cloud end to calculate an SOC (system on chip) correction value, calling voltage information and current information of the target battery before standing to calculate the change capacity after the target battery enters the voltage platform area by the cloud end, obtaining the interval capacity and the interval SOC value corresponding to the voltage platform area by the cloud end, calculating a correction value SOCx according to the change capacity, the interval capacity and the interval SOC value, and correcting the current SOC of the target battery according to the correction value SOCx. According to the invention, the existing BMS hardware is not required to be modified, the modification cost is reduced, the SOC of the lithium ion battery is modified in the voltage platform area, and the SOC estimation precision of the lithium ion battery is improved.

Description

Lithium ion battery SOC correction method, system, equipment and medium
Technical Field
The invention relates to the technical field of battery management, in particular to a lithium ion battery SOC correction method, a lithium ion battery SOC correction system, lithium ion battery SOC correction equipment and a lithium ion battery SOC correction medium.
Background
The lithium battery can not be used without a battery management system BMS, the battery management system BMS is used as a key part for ensuring the normal and safe use of the battery and prolonging the service life of the battery, and one of the core functions is SOC estimation. The state of charge SOC is the state of charge, which reflects the current remaining capacity of the battery, which is defined as the percentage of the current remaining capacity of the battery to the total capacity.
The conventional common SOC estimation method comprises ampere-hour integration and static voltage correction, wherein the current sampling error of the ampere-hour integration causes inevitable error in the long-term use process; a common SOC correction method is to correct the SOC by looking up a table through an OCV curve using a static voltage. However, when the method is applied to a lithium ion battery system of an LFP (lithium iron phosphate) system, the lithium ion battery of the LFP (lithium iron phosphate) system has an obvious OCV voltage platform, and the acquisition precision of the cell voltage is limited, so that the SOC value of the platform area cannot be accurately corrected.
In the prior art, for example, chinese patent publication No. CN110967644a discloses a correction method of battery pack SOC, a battery management system and a vehicle, introduces SOC correction using capacity differentiation in an SOC-OCV non-attenuation region, and corrects the SOC value of the battery pack during charging of the battery pack; the influence of battery aging on the SOC value calculation of the battery pack is avoided, and the accuracy of the corrected SOC value of the battery pack is improved. This patent only corrects to the SOC interval in non-attenuation district, in addition, need utilize the electric core of different attenuation degrees to carry out the OCV test, discerns non-attenuation district, and is higher to the degree of dependence of electric core research and development data.
Disclosure of Invention
In order to solve the problems, the technical scheme provided by the invention is as follows:
a lithium ion battery SOC correction method comprises
Acquiring the static voltage of a target battery; acquiring the voltage, the current and the temperature of a monomer in real time in the charging and discharging process of the target battery;
judging whether the static voltage is in a voltage plateau area of the target battery;
if the static voltage is not in the voltage leveling area, correcting the current SOC of the target battery through an OCV-SOC curve of the lithium ion battery;
if the static voltage is in the voltage platform area, requesting a cloud end to calculate an SOC correction value, calling voltage information and current information of the target battery before standing to calculate the change capacity after the target battery enters the voltage platform area, obtaining the interval capacity and the interval SOC value corresponding to the voltage platform area by the cloud end, calculating a correction value SOCx according to the change capacity, the interval capacity and the interval SOC value, and correcting the current SOC of the target battery according to the correction value SOCx.
The invention is further configured in such a way that the cloud calls a voltage charging/discharging curve and a current charging/discharging curve of the target battery before standing, calculates a capacity differential curve of the target battery in the charging/discharging process before standing, and calculates the area of the capacity differential curve according to the voltage of the target battery at the end of charging/discharging so as to obtain the change capacity of the target battery after entering the voltage leveling area.
The invention further sets the change capacity of the target battery entering the voltage platform area in the charging/discharging process to be Qs; the interval capacity corresponding to the voltage leveling area is Qc; the SOC values of the interval corresponding to the voltage platform area are SOCa and SOCb, wherein SOCb is larger than SOCa;
during charging of the target battery, the correction value SOCx = SOCa + Qs/Qc x (SOCb-SOCa), where the change capacity Qs is the capacity accumulated after the target battery enters the voltage plateau;
the correction value SOCx = SOCb-Qs/Qc × (SOCb-SOCa) during the discharge of the target battery, where the change capacity Qs is a capacity consumed after the target battery enters the voltage plateau region.
The invention further provides that the cloud end stores the charging/discharging curve of the target battery under typical temperature and without capacity attenuation, and records the charging/discharging curve of the target battery in each complete charging so as to obtain charging/discharging capacity differential curves under different temperatures and different capacity attenuation degrees.
The method is further configured that when the cloud computing SOC correction value is requested, the charging/discharging capacity differential curve corresponding to the temperature and the capacity attenuation degree is searched in the cloud database by taking the temperature and the capacity attenuation degree as indexes;
if the charging/discharging capacity differential curve corresponding to the temperature and the capacity attenuation degree exists in the cloud database, calling the charging/discharging capacity differential curve corresponding to the temperature and the capacity attenuation degree, and calculating the interval capacity and the interval SOC value corresponding to the voltage leveling platform area;
if the charging/discharging capacity differential curve corresponding to the temperature and the capacity attenuation degree does not exist in the cloud database, calling the charging/discharging capacity differential curve adjacent to the temperature and the capacity attenuation degree, and calculating the interval capacity and the interval SOC value corresponding to the voltage platform area by utilizing an interpolation algorithm.
The method is further configured to obtain the current SOC0 of the target battery if the static voltage is in the voltage platform area, receive the cloud return correction value SOCx, and correct the SOC change rate of the target battery in the charging process by increasing or decreasing the SOC change rate if the absolute value SOCx-SOC0 is greater than or equal to n and n is a first correction threshold value.
The method is further configured to obtain the current SOC0 of the target battery if the static voltage is not in the voltage plateau region, query a corrected value SOCx corresponding to an OCV-SOC curve of the lithium ion battery according to the static voltage, and correct the SOC change rate of the target battery in the charging process by increasing or decreasing the SOC change rate if the absolute value SOCx-SOC0 is greater than or equal to m and m is a second corrected threshold value.
A lithium ion battery SOC correction system adopts the lithium ion battery SOC correction method, and comprises the following steps:
a target battery to be corrected;
the battery management unit BMS is used for acquiring the static voltage of the target battery and acquiring the voltage, current and temperature data of the battery in real time in the charging process of the target battery; when the static voltage of the target battery is in a non-voltage plateau area, judging whether to correct the current SOC of the target battery or not through an OCV-SOC curve of the lithium ion battery; when the static voltage of the target battery is in a voltage platform area, sending a calculation request to a cloud end, and judging whether to correct the current SOC of the target battery according to a correction value returned by the cloud end;
the cloud storage and calculation unit is used for storing a charging/discharging curve of the target battery under typical temperature and no capacity attenuation and recording the charging/discharging curve of each complete charging of the target battery; acquiring a calculation request sent by a battery management unit BMS, calling voltage information and current information of the target battery before standing to calculate the change capacity after entering a voltage platform area, acquiring the interval capacity and the interval SOC value corresponding to the voltage platform area, calculating a correction value according to the change capacity, the interval capacity and the interval SOC value, and returning the correction value to the battery management unit BMS;
the data transmission unit is used for transmitting a calculation request, static voltage, cell voltage, current and temperature data which are sent to the cloud storage and calculation unit by the battery management unit BMS; and the correction value is used for transmitting the correction value returned by the cloud storage and calculation unit to the battery management unit BMS.
An electronic device comprising a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to execute the lithium ion battery SOC correction method described above.
A storage medium having stored thereon computer program instructions which, when executed by a processor, implement the above-described lithium ion battery SOC correction method.
Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:
the lithium ion battery SOC correction method of the invention carries out classified correction on a voltage platform area and a non-voltage platform area of static voltage, obtains a correction value by directly inquiring an OCV-SOC curve of a lithium ion battery for a target battery of which the static voltage is in the non-voltage platform area, and compares the correction value with the current SOC of the target battery to judge whether to carry out SOC correction; for a target battery with static voltage in a voltage platform area, a calculation request is sent to a cloud end, the cloud end calls voltage information and current information of the target battery before standing to calculate the change capacity after the target battery enters the voltage platform area, the interval capacity and the interval SOC value corresponding to the voltage platform area are obtained, a correction value is calculated according to the change capacity, the interval capacity and the interval SOC value and returned to a battery management unit BMS, and the battery management unit BMS judges whether the current SOC of the target battery is corrected according to the correction value returned by the cloud end.
According to the invention, the charge/discharge information of the target battery is continuously stored by using the super-large storage space and the computing capability of the cloud, when the static voltage of the target battery is in the voltage platform area, the change capacity after the target battery enters the voltage platform area is calculated by combining the voltage information and the current information before the target battery is stood, the interval capacity and the interval SOC value corresponding to the voltage platform area are calculated by the complete charge/discharge information of the target battery in the past, so that the corrected value is calculated and returned to the battery management unit BMS, the existing BMS hardware is not required to be modified, the modification cost is reduced, the SOC of the lithium ion battery is modified in the voltage platform area, and the SOC estimation precision is improved.
The cloud storage and calculation unit can also establish charge and discharge curves of the target battery under different temperatures and different capacity attenuation degrees to obtain corresponding capacity differential curves, and when the cloud storage and calculation unit receives a calculation request of the battery management unit BMS, the cloud storage and calculation unit can call the capacity differential curves with the same temperature and the same attenuation degree as the current battery state, so that the correction error is further reduced.
Drawings
Fig. 1 is a flowchart of a lithium ion battery SOC correction method according to an embodiment of the present invention.
Fig. 2 is a graph of OCV-SOC of a lithium ion battery according to an embodiment of the present invention.
Fig. 3 is a typical standard charging voltage-SOC variation graph according to an embodiment of the present invention.
FIG. 4 is a graph of typical differential standard charge capacity (dQ/dV-V) curves for an embodiment of the present invention.
Fig. 5 is a block diagram of a system for correcting the SOC of a lithium ion battery according to an embodiment of the present invention.
FIG. 6 is a schematic diagram of an apparatus according to an embodiment of the present invention.
Detailed Description
For a further understanding of the present invention, reference will now be made in detail to the embodiments illustrated in the drawings.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as being fixedly connected, integrally connected, or detachably connected; either mechanically or electrically, or internally communicating two elements; they may be directly connected or indirectly connected through an intermediate, and those skilled in the art will understand the specific meanings of the above terms according to specific situations.
Example 1
With reference to fig. 1 to 4, the technical scheme of the invention is a lithium ion battery SOC correction method, which comprises the steps of
Acquiring the static voltage of a target battery; acquiring the voltage, the current and the temperature of a monomer in real time in the charging and discharging process of the target battery;
judging whether the static voltage is in a voltage plateau area of the target battery;
if the static voltage is not in the voltage leveling area, correcting the current SOC of the target battery through an OCV-SOC curve of the lithium ion battery;
if the static voltage is in the voltage platform area, requesting a cloud end to calculate an SOC correction value, calling voltage information and current information of the target battery before standing to calculate the change capacity after the target battery enters the voltage platform area, obtaining the interval capacity and the interval SOC value corresponding to the voltage platform area by the cloud end, calculating a correction value SOCx according to the change capacity, the interval capacity and the interval SOC value, and correcting the current SOC of the target battery according to the correction value SOCx.
In the above embodiment, the lithium ion battery SOC correction method of this embodiment classifies and corrects the voltage plateau area and the non-voltage plateau area of the static voltage, obtains a correction value by directly querying an OCV-SOC curve of the lithium ion battery for the target battery with the static voltage in the non-voltage plateau area, and compares the correction value with the current SOC of the target battery to determine whether to perform SOC correction; for a target battery with static voltage in a voltage platform area, a calculation request is sent to a cloud end, the cloud end calls voltage information and current information of the target battery before standing to calculate the change capacity after the target battery enters the voltage platform area, the interval capacity and the interval SOC value corresponding to the voltage platform area are obtained, a correction value is calculated according to the change capacity, the interval capacity and the interval SOC value and returned to a battery management unit BMS, and the battery management unit BMS judges whether the current SOC of the target battery is corrected according to the correction value returned by the cloud end.
In the above embodiment, the determination condition current of the static voltage is less than x and lasts for more than y time; for example, the specific determination conditions: the current was less than 1A for more than 1h. The monitoring and the judgment of the static voltage are managed by a battery management unit BMS.
In this embodiment, the cloud calls a voltage charging/discharging curve and a current charging/discharging curve of the target battery before standing, calculates a capacity differential curve during the charging/discharging process of the target battery before standing, and calculates an area of the capacity differential curve according to a voltage of the target battery at the end of charging/discharging, so as to obtain a change capacity of the target battery after entering the voltage plateau area.
In this embodiment, the variable capacity of the target battery entering the voltage plateau region during the charge/discharge process is Qs; the interval capacity corresponding to the voltage leveling area is Qc; the SOC values of the interval corresponding to the voltage platform area are SOCa and SOCb, wherein SOCb is larger than SOCa;
during charging of the target battery, the corrected value SOCx = SOCa + Qs/Qc × (SOCb-SOCa), where the varied capacity Qs is the accumulated capacity of the target battery after entering the voltage plateau;
the correction value SOCx = SOCb-Qs/Qc × (SOCb-SOCa) during the discharge of the target battery, where the change capacity Qs is a capacity consumed after the target battery enters the voltage plateau region.
In the above embodiment, the varied capacity Qs is obtained by the cloud calling a voltage charge/discharge curve and a current charge/discharge curve of the target battery before standing, calculating a capacity differential curve during charge/discharge of the target battery before standing, and calculating an area of the capacity differential curve from a voltage at the end of charge/discharge of the target battery.
In the above embodiment, the interval capacity Qc corresponding to the voltage plateau area is obtained according to the existing complete charge/discharge curve of the cloud, and in order to obtain a more accurate (smaller deviation) complete charge/discharge curve, a database is established by using the factors affecting the complete charge/discharge curve, namely, the temperature and the capacity fading degree, as the variation, so that the cloud stores a large number of completely charged charge/discharge curves at different temperatures and with different capacity fading degrees, which will be described in detail below.
In this embodiment, the cloud stores a charging/discharging curve of the target battery at a typical temperature without capacity fading in advance, and records a charging/discharging curve of the target battery in each complete charging in a subsequent charging/discharging process of the target battery to obtain differential curves of charging/discharging capacities at different temperatures and different capacity fading degrees.
In the above embodiment, the charging information of the target battery is continuously stored by using the ultra-large storage space and the computing capability of the cloud, when the static voltage of the target battery is in the voltage platform area, the change capacity after the target battery enters the voltage platform area is calculated by combining the voltage information and the current information before the target battery stands, the interval capacity and the interval SOC value corresponding to the voltage platform area are calculated by the complete charging and discharging information of the target battery in the past, so that the correction value is calculated and returned to the battery management unit BMS, the existing BMS hardware does not need to be modified, the modification cost is reduced, the SOC of the lithium ion battery is modified in the voltage platform area, and the SOC estimation precision is improved
In this embodiment, when a cloud is requested to calculate an SOC correction value, a charging/discharging capacity differential curve corresponding to a temperature and a capacity attenuation degree is searched in the cloud database by using the temperature and the capacity attenuation degree as indexes;
if the charging/discharging capacity differential curve corresponding to the temperature and the capacity attenuation degree exists in the cloud database, calling the charging/discharging capacity differential curve corresponding to the temperature and the capacity attenuation degree, and calculating interval capacity and an interval SOC value corresponding to the voltage platform area;
if the charging/discharging capacity differential curve corresponding to the temperature and the capacity attenuation degree does not exist in the cloud database, calling the charging/discharging capacity differential curve adjacent to the temperature and the capacity attenuation degree, and calculating the interval capacity and the interval SOC value corresponding to the voltage platform area by utilizing an interpolation algorithm.
In the above embodiment, the cloud storage and calculation unit establishes the charge and discharge curves of the target battery at different temperatures and different capacity attenuation degrees to obtain corresponding capacity differential curves, and when the cloud storage and calculation unit receives a calculation request of the battery management unit BMS, the cloud storage and calculation unit may call the capacity differential curve at the same temperature and the same attenuation degree as the current battery state, so as to further reduce the corrected error.
In this embodiment, if the static voltage is in the voltage plateau, obtaining the current SOC0 of the target battery, and receiving the cloud return correction value SOCx, and if | SOCx-SOC0| ≧ n, where n is a first correction threshold, performing correction by increasing or decreasing the SOC change rate of the target battery during charging.
In this embodiment, if the static voltage is not in the voltage plateau region, obtaining the current SOC0 of the target battery, and querying a correction value SOCx corresponding to an OCV-SOC curve of the lithium ion battery according to the static voltage, and if | SOCx-SOC0| ≧ m, where m is a second correction threshold, correcting by increasing or decreasing the SOC change rate of the target battery in the charging process.
In the above embodiment, the first modification threshold and the second modification threshold may have different values, and the first modification threshold and the second modification threshold may also have the same value.
In the above embodiment, whether the static voltage is in the voltage leveling area and | SOCx-SOC0| ≧ n, or the static voltage is not in the voltage leveling area and | SOCx-SOC0| ≧ m, the SOC change rate of the target battery is adjusted according to the subsequent operating condition. For example, the current reported value SOC0 is 30%, the correction value SOCx queried by the static cell voltage is 40%, the error at this time is-10%, and the SOC needs to be corrected in the increasing direction, but the SOC0 cannot be directly changed to 40% because the SOC cannot change suddenly. Assuming that the latter condition is continued charging and the rate of correction is assumed to be 1%/min, it is necessary to add 1% per minute to the ampere-hour integral (SOC is greater), i.e., increase the rate of change of SOC. Assuming the latter condition is sustained discharge, and also assuming a correction rate of 1%/min, it is necessary to add 1% to the ampere-hour integral (SOC decreasing), i.e., to reduce or slow down the rate of change of SOC, per minute.
To further illustrate the present solution, examples are given:
as shown in fig. 2, it is a lithium ion battery OCV-SOC curve diagram, the lithium ion battery OCV has obvious voltage plateau regions [ V1, V2] and [ V3, V4], and the interval SOC values corresponding to the voltage plateau regions [ V1, V2] and [ V3, V4] are SOC1, SOC2, SOC3, SOC4; when the battery management unit BMS acquires the static voltage V0, starting a correction process;
if the static voltage V0 is not in the voltage plateau region, that is, V0 is greater than V1 or V2 is greater than V0 is greater than V3 or V4 is less than V0, the correction value SOCx is obtained by querying the OCV-SOC curve, and whether to correct the SOC is determined according to the difference between the correction value SOCx and the current SOC0 reported by the battery management unit BMS, and the correction steps are as described above and are not repeated.
As shown in fig. 3, a typical standard charging voltage-SOC variation graph is shown,stored in the cloud, and two voltage platform areas V5 and V6 exist as the OCV-SOC curve diagram]And [ V7, V8 ]]The differential capacity curve (dQ/dV-V) of the complete charging process can be obtained by differentiating the voltage by the capacity by using the voltage variation curve of the complete charging process, a typical differential capacity curve of the charging process is shown in figure 4, a peak point exists between V5 and V6, a peak point exists between V7 and V8, and a voltage plateau area [ V5, V6 ] can be obtained by the area below the differential capacity curve]Interval capacity Q of 56 Or voltage plateau [ V7, V8 ]]Interval capacity Q of 78 。
If the static voltage V0 is in the voltage platform area, the battery management unit BMS acquires the static voltage V1 after constant current charging<V0<V2 is taken as an example, the cloud calls a voltage charging curve and a current charging curve of the target battery before standing, a capacity differential curve in the charging process of the target battery before standing is calculated, the area of the capacity differential curve is calculated to obtain the change capacity Q1 of the target battery after entering the voltage leveling area, and the corrected value SOCx = SOC1+ Q is calculated 1 /Q 56 And (SOC 2-SOC 1), returning the corrected value SOCx to the battery management unit BMS, and judging whether to correct the SOC according to the difference between the corrected value SOCx and the current SOC0 reported by the battery management unit BMS.
Example 2
With reference to fig. 5, the technical solution of the present invention is a lithium ion battery SOC correction system, and the lithium ion battery SOC correction method according to embodiment 1 includes:
a target battery 10 to be corrected;
the battery management unit BMS20 is used for collecting the static voltage of the target battery and simultaneously collecting the voltage, current and temperature data of the single battery in real time in the charging process of the target battery; when the static voltage of the target battery is in a non-voltage plateau area, judging whether to correct the current SOC of the target battery or not through an OCV-SOC curve of the lithium ion battery; when the static voltage of the target battery is in a voltage platform area, sending a calculation request to a cloud end, and judging whether to correct the current SOC of the target battery according to a correction value returned by the cloud end;
the cloud storage and calculation unit 30 is used for storing a charging/discharging curve of the target battery under typical temperature and no capacity attenuation and recording a charging/discharging curve of each complete charging of the target battery; acquiring a calculation request sent by a battery management unit BMS, calling voltage information and current information of the target battery before standing to calculate the change capacity after entering a voltage platform area, acquiring the interval capacity and the interval SOC value corresponding to the voltage platform area, calculating a correction value according to the change capacity, the interval capacity and the interval SOC value, and returning the correction value to the battery management unit BMS;
the data transmission unit 40 is used for transmitting the calculation request, the static voltage, the cell voltage, the current and the temperature data which are sent to the cloud storage and calculation unit by the battery management unit BMS; and the correction value is used for transmitting the correction value returned by the cloud storage and calculation unit to the battery management unit BMS.
Example 3
With reference to fig. 6, an electronic device includes a memory 200 and a processor 100, where the memory stores a computer program, and the computer program, when executed by the processor 100, causes the processor 100 to execute the lithium ion battery SOC correction method according to embodiment 1.
Example 4
A storage medium having stored thereon computer program instructions which, when executed by a processor, implement the above-described lithium ion battery SOC correction method.
The present invention and its embodiments have been described above schematically, without limitation, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching, without departing from the spirit of the invention, the person skilled in the art shall not inventively design the similar structural modes and embodiments to the technical solution, but shall fall within the scope of the invention.

Claims (10)

1. A lithium ion battery SOC correction method is characterized by comprising
Acquiring the static voltage of a target battery; acquiring the voltage, the current and the temperature of a monomer in real time in the charging and discharging process of the target battery;
judging whether the static voltage is in a voltage plateau area of the target battery;
if the static voltage is not in the voltage leveling area, correcting the current SOC of the target battery through an OCV-SOC curve of the lithium ion battery;
if the static voltage is in the voltage platform area, requesting a cloud end to calculate an SOC correction value, calling voltage information and current information of the target battery before standing to calculate the change capacity after the target battery enters the voltage platform area, obtaining the interval capacity and the interval SOC value corresponding to the voltage platform area by the cloud end, calculating a correction value SOCx according to the change capacity, the interval capacity and the interval SOC value, and correcting the current SOC of the target battery according to the correction value SOCx.
2. The method of claim 1, wherein the cloud calls a voltage charge/discharge curve and a current charge/discharge curve of the target battery before standing, calculates a capacity differential curve during the charge/discharge process of the target battery before standing, and calculates an area of the capacity differential curve according to a voltage at the end of the charge/discharge of the target battery to obtain a changed capacity of the target battery after entering the voltage leveling zone.
3. The method of claim 2, wherein the variation capacity of the target battery entering the voltage leveling zone during the charging/discharging process is Qs; the interval capacity corresponding to the voltage leveling area is Qc; the SOC values of the interval corresponding to the voltage platform area are SOCa and SOCb, wherein SOCb is larger than SOCa;
during charging of the target battery, the corrected value SOCx = SOCa + Qs/Qc × (SOCb-SOCa), where the varied capacity Qs is the accumulated capacity of the target battery after entering the voltage plateau;
the correction value SOCx = SOCb-Qs/Qc × (SOCb-SOCa) during the discharge of the target battery, where the change capacity Qs is a capacity consumed after the target battery enters the voltage plateau region.
4. The method of claim 3, wherein the cloud stores a charging/discharging curve of the target battery at a typical temperature without capacity fading, and the cloud records the charging/discharging curve of the target battery in each complete charging so as to obtain differential curves of charging/discharging capacities at different temperatures and different capacity fading degrees.
5. The method of claim 4, wherein when requesting a cloud to calculate the SOC correction value, using the temperature and the capacity fade degree as an index, searching a charging/discharging capacity differential curve corresponding to the temperature and the capacity fade degree in the cloud database;
if the charging/discharging capacity differential curve corresponding to the temperature and the capacity attenuation degree exists in the cloud database, calling the charging/discharging capacity differential curve corresponding to the temperature and the capacity attenuation degree, and calculating the interval capacity and the interval SOC value corresponding to the voltage leveling platform area;
if the charging/discharging capacity differential curve corresponding to the temperature and the capacity attenuation degree does not exist in the cloud database, calling the charging/discharging capacity differential curve adjacent to the temperature and the capacity attenuation degree, and calculating the interval capacity and the interval SOC value corresponding to the voltage platform area by utilizing an interpolation algorithm.
6. The method of any one of claims 1 to 5, wherein if the static voltage is in the voltage plateau region, obtaining a current SOC0 of the target battery, and receiving the cloud return correction value SOCx, and if | SOCx-SOC0| ≧ n, where n is a first correction threshold, correcting by increasing or decreasing the SOC change rate of the target battery during charging.
7. The method of any one of claims 1 to 5, wherein if the static voltage is not in the voltage plateau region, obtaining a current SOC0 of the target battery, and querying a correction value SOCx corresponding to an OCV-SOC curve of the lithium ion battery according to the static voltage, and if | SOCx-SOC0| ≧ m, m is a second correction threshold, performing correction by increasing or decreasing the SOC change rate of the target battery during charging.
8. A lithium ion battery SOC correction system, characterized in that the lithium ion battery SOC correction method according to any one of claims 1 to 7 is adopted, and the method includes:
a target battery to be corrected;
the battery management unit BMS is used for acquiring the static voltage of the target battery and acquiring the voltage, current and temperature data of the battery in real time in the charging process of the target battery; when the static voltage of the target battery is in a non-voltage plateau area, judging whether to correct the current SOC of the target battery or not through an OCV-SOC curve of the lithium ion battery; when the static voltage of the target battery is in a voltage platform area, sending a calculation request to a cloud end, and judging whether to correct the current SOC of the target battery according to a correction value returned by the cloud end;
the cloud storage and calculation unit is used for storing a charging/discharging curve of the target battery under typical temperature and no capacity attenuation and recording the charging/discharging curve of each complete charging of the target battery; acquiring a calculation request sent by a battery management unit BMS, calling voltage information and current information of the target battery before standing to calculate the change capacity after entering a voltage platform area, acquiring the interval capacity and the interval SOC value corresponding to the voltage platform area, calculating a correction value according to the change capacity, the interval capacity and the interval SOC value, and returning the correction value to the battery management unit BMS;
the data transmission unit is used for transmitting a calculation request, static voltage, cell voltage, current and temperature data which are sent to the cloud storage and calculation unit by the battery management unit BMS; and the correction value is used for transmitting the correction value returned by the cloud storage and calculation unit to the battery management unit BMS.
9. An electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and wherein the computer program, when executed by the processor, causes the processor to perform the lithium ion battery SOC correction method of any of claims 1 to 7.
10. A storage medium having stored thereon computer program instructions which, when executed by a processor, implement the lithium ion battery SOC correction method of any one of claims 1 to 7.
CN202211128448.2A 2022-09-16 2022-09-16 Lithium ion battery SOC correction method, system, equipment and medium Pending CN115684966A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116298931A (en) * 2023-05-12 2023-06-23 四川新能源汽车创新中心有限公司 Cloud data-based lithium ion battery capacity estimation method
CN116699448A (en) * 2023-08-09 2023-09-05 合肥工业大学 Lithium phosphate battery platform-stage SOC correction method, device and system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116298931A (en) * 2023-05-12 2023-06-23 四川新能源汽车创新中心有限公司 Cloud data-based lithium ion battery capacity estimation method
CN116298931B (en) * 2023-05-12 2023-09-01 四川新能源汽车创新中心有限公司 Cloud data-based lithium ion battery capacity estimation method
CN116699448A (en) * 2023-08-09 2023-09-05 合肥工业大学 Lithium phosphate battery platform-stage SOC correction method, device and system
CN116699448B (en) * 2023-08-09 2023-12-26 合肥工业大学 Lithium phosphate battery platform-stage SOC correction method, device and system

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