CN117293979B - Battery equalization control method, storage medium and electronic device - Google Patents
Battery equalization control method, storage medium and electronic device Download PDFInfo
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- CN117293979B CN117293979B CN202311586227.4A CN202311586227A CN117293979B CN 117293979 B CN117293979 B CN 117293979B CN 202311586227 A CN202311586227 A CN 202311586227A CN 117293979 B CN117293979 B CN 117293979B
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- 238000000034 method Methods 0.000 title claims abstract description 47
- 239000000178 monomer Substances 0.000 claims abstract description 48
- 230000001960 triggered effect Effects 0.000 claims abstract description 9
- 230000004044 response Effects 0.000 claims abstract description 8
- 238000007599 discharging Methods 0.000 claims description 13
- 238000006243 chemical reaction Methods 0.000 abstract description 6
- 230000000694 effects Effects 0.000 description 6
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 6
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000013507 mapping Methods 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000012163 sequencing technique Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
- H02J7/0014—Circuits for equalisation of charge between batteries
- H02J7/0016—Circuits for equalisation of charge between batteries using shunting, discharge or bypass circuits
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4207—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells for several batteries or cells simultaneously or sequentially
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/44—Methods for charging or discharging
- H01M10/441—Methods for charging or discharging for several batteries or cells simultaneously or sequentially
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/00306—Overdischarge protection
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
- H02J7/0048—Detection of remaining charge capacity or state of charge [SOC]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
- H01M2010/4271—Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
-
- 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
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Secondary Cells (AREA)
Abstract
The application discloses a battery balance control method, a storage medium and electronic equipment, wherein the method comprises the following steps: determining an equalization target capacity in response to a battery equalization operation being triggered; determining the current residual capacity of each cell unit according to an OCV-SOC characteristic curve, and determining the cell unit with the current residual capacity higher than the balance target capacity as the balance cell unit, wherein for the cell unit with the open-circuit voltage in a capacity non-mappable interval in the OCV-SOC characteristic curve, the lower limit residual capacity corresponding to the capacity non-mappable interval in which the open-circuit voltage of the cell unit is positioned is taken as the current residual capacity; and determining the balanced discharge time of each balanced battery cell monomer according to the current residual capacity and the balanced target capacity of each balanced battery cell monomer, and controlling each balanced battery cell monomer to discharge the balanced discharge time, so that the purpose of balancing the battery can be achieved, and the occurrence of reaction caused by overdischarge of the battery cell monomer in a capacity unmapped interval can be avoided.
Description
Technical Field
The present disclosure relates to the field of battery technologies, and in particular, to a battery equalization control method, a storage medium, and an electronic device.
Background
Currently, a ternary lithium ion battery and a lithium iron phosphate battery are mostly used as power batteries of electric automobiles. The two system batteries show various external characteristics with a great difference, wherein an OCV-SOC characteristic curve (open-circuit voltage-battery residual capacity characteristic curve) is ideal, and the curve slope of the ternary lithium ion battery can better map the SOC of a single body according to the voltage of the single body. As shown in FIG. 1, the OCV-SOC curve of lithium iron phosphate has a very small slope in two sections of 30% -50% and 60% -99% of SOC, which is not beneficial to obtaining a corresponding SOC value by using OCV voltage mapping.
For a battery with an imperfect OCV-SOC curve, such as a lithium iron phosphate battery, in the battery equalization operation, if the SOC is estimated by adopting the OCV-SOC curve, estimation deviation is very easy to occur, so that not only can a good equalization effect be not obtained, but also the equalization function can be reacted. Accordingly, it is desirable to provide a battery equalization control method suitable for batteries with non-ideal OCV-SOC curves.
Disclosure of Invention
The application aims to overcome the defect that a battery with an undesirable OCV-SOC curve such as a lithium iron phosphate battery cannot achieve a good balancing effect in the prior art, and provides a battery balancing control method, a storage medium and electronic equipment.
The technical scheme of the application provides a battery equalization control method, which comprises the following steps:
determining an equalization target capacity in response to a battery equalization operation being triggered;
determining the current residual capacity of each cell unit according to an OCV-SOC characteristic curve, and determining the cell unit with the current residual capacity higher than the balance target capacity as the balance cell unit, wherein for the cell unit with the open-circuit voltage in a capacity non-mappable interval in the OCV-SOC characteristic curve, the lower limit residual capacity corresponding to the capacity non-mappable interval in which the open-circuit voltage of the cell unit is positioned is taken as the current residual capacity;
and determining the balanced discharge time of each balanced cell unit according to the current residual capacity and the balanced target capacity of each balanced cell unit, and controlling each balanced cell unit to discharge the balanced discharge time.
Further, the determining the equalization target capacity specifically includes:
acquiring an open-circuit voltage of each cell unit, and selecting the cell unit with the open-circuit voltage in a capacity mappable interval in an OCV-SOC characteristic curve as a reference cell unit;
determining the current residual capacity of each reference cell unit according to an OCV-SOC characteristic curve;
determining a preset number of reference cell monomers with lower current residual capacity as target cell monomers;
and calculating the current residual capacity average value of the target battery cell monomer as an equilibrium target capacity.
Further, before the responding to the battery equalization operation is triggered, the method further comprises:
if the real-time battery pack electric quantity is within the preset balanced electric quantity range, the open-circuit voltage corresponding to the preset balanced electric quantity range is a capacity mappable interval in the OCV-SOC characteristic curve, and/or
The lowest temperature of the battery pack is greater than or equal to a preset temperature threshold, and/or
And starting the vehicle after the standing time of the battery pack is greater than or equal to the preset standing time, and triggering the battery balancing operation.
Further, the battery equalization control method further includes:
in response to the completion of battery pack charging, selecting a cell unit with an open-circuit voltage greater than or equal to a preset open-circuit voltage as an equalization cell unit, wherein the preset open-circuit voltage is in a capacity mappable interval in an OCV-SOC characteristic curve;
determining the residual capacity corresponding to the preset open-circuit voltage as an equalization target capacity according to an OCV-SOC characteristic curve, and the current residual capacity of each equalization battery cell;
and determining the balanced discharge time of each balanced cell unit according to the current residual capacity and the balanced target capacity of each balanced cell unit, and controlling each balanced cell unit to discharge the balanced discharge time.
Further, the determining the balanced discharge time of each balanced cell unit according to the current remaining capacity and the balanced target capacity of each balanced cell unit specifically includes:
calculating a capacity difference value between the current residual capacity and the balance target capacity;
the equilibrium discharge time is calculated according to the following formula:
T=ΔSOC*S/I
wherein T is the balanced discharge time, delta SOC is the capacity difference, S is the nominal capacity of the battery cell, and I is the balanced effective current.
Further, before the controlling each of the balanced cell units to discharge the balanced discharge time, the method further includes:
if the real-time battery pack capacity is greater than the lower limit balance capacity, and/or
The output current of the battery pack is smaller than the upper limit equalizing current
And controlling each balanced cell unit to discharge the balanced discharge time.
Further, when the control of discharging each of the balance battery cell units for the balance discharging time is executed, if the vehicle enters a dormant state, the current discharging progress is stored, and the discharging operation is continuously executed when the vehicle is awakened next time.
Further, when the balanced discharge time of each balanced cell unit is controlled to be discharged, if a new balanced discharge strategy is received, the balanced discharge time of each balanced cell unit is controlled according to the new balanced discharge strategy.
The technical scheme of the application also provides a storage medium which stores computer instructions and is used for executing the battery balance control method when the computer executes the computer instructions.
The technical scheme of the application also provides electronic equipment, which comprises at least one processor; the method comprises the steps of,
a memory communicatively coupled to the at least one processor; wherein,
the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the battery equalization control method as previously described.
After the technical scheme is adopted, the method has the following beneficial effects:
when the equalization operation is executed, for the battery cell with the open-circuit voltage in the capacity unmapped section in the OCV-SOC characteristic curve, the lower limit residual capacity corresponding to the capacity unmapped section with the open-circuit voltage is used as the current residual capacity of the battery cell, so that whether the battery cell is the equalization battery cell which needs to be discharged and the corresponding equalization discharge time are judged, the purpose of battery equalization can be achieved, and the occurrence of reaction caused by overdischarge of the battery cell in the capacity unmapped section can be avoided.
Drawings
The disclosure of the present application will become more readily understood with reference to the accompanying drawings. It should be understood that: the drawings are for illustrative purposes only and are not intended to limit the scope of the present application. In the figure:
FIG. 1 is a schematic diagram of the OCV-SOC characteristics of a lithium iron phosphate battery;
FIG. 2 is a flow chart of a battery equalization control method in an embodiment of the present application;
FIG. 3 is a flow chart of a battery equalization control method in accordance with a preferred embodiment of the present application;
fig. 4 is a schematic diagram of a hardware structure of an electronic device according to an embodiment of the present application.
Detailed Description
Specific embodiments of the present application are further described below with reference to the accompanying drawings.
It is easy to understand that, according to the technical solution of the present application, those skilled in the art may replace various structural manners and implementation manners without changing the true spirit of the present application. Accordingly, the following detailed description and drawings are merely illustrative of the present application and are not intended to be exhaustive or to be limiting of the application.
Terms of orientation such as up, down, left, right, front, rear, front, back, top, bottom, etc. mentioned or possible to be mentioned in the present specification are defined with respect to the configurations shown in the drawings, which are relative concepts, and thus may be changed according to different positions and different use states thereof. These and other directional terms should not be construed as limiting terms. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between the two components. The above-described specific meanings belonging to the present application are understood as appropriate by those of ordinary skill in the art.
The battery equalization control method in the embodiment of the present application, as shown in fig. 2, includes:
step S201: determining an equalization target capacity in response to a battery equalization operation being triggered;
step S202: determining the current residual capacity of each cell unit according to an OCV-SOC characteristic curve, and determining the cell unit with the current residual capacity higher than the balance target capacity as the balance cell unit, wherein for the cell unit with the open-circuit voltage in a capacity non-mappable interval in the OCV-SOC characteristic curve, the lower limit residual capacity corresponding to the capacity non-mappable interval in which the open-circuit voltage of the cell unit is positioned is taken as the current residual capacity;
step S203: and determining the balanced discharge time of each balanced cell unit according to the current residual capacity and the balanced target capacity of each balanced cell unit, and controlling each balanced cell unit to discharge the balanced discharge time.
Specifically, when the power battery pack and the vehicle state satisfy the battery equalization condition, the battery equalization operation is triggered, and then the equalization target capacity is determined according to the remaining capacity condition of each cell in the battery pack. And the balance target capacity is the target capacity of the battery cell after the battery cell performs balance discharge.
The OCV-SOC characteristic curve is a curve showing a correspondence relationship between an Open Circuit Voltage (OCV) and a remaining capacity (SOC) of a battery cell, fig. 1 shows an example of the OCV-SOC characteristic curve, wherein the open circuit voltage includes a capacity mappable interval and a capacity unmapped interval, the OCV-SOC characteristic curve has an obvious slope in the capacity mappable interval, the remaining capacity corresponding to each open circuit voltage is different, and the open circuit voltage corresponding to the remaining capacity in fig. 1 is 0% -30%, 50% -60%, 99% -100% is the capacity mappable interval; the OCV-SOC characteristic curve has a slope of almost 0 in the capacity non-mappable region, one open circuit voltage corresponds to a plurality of remaining capacities, and in fig. 1, the open circuit voltage corresponding to 30% -50% and 60% -99% of the remaining capacities is the capacity non-mappable region, and in this region, it is impossible to estimate an accurate remaining capacity from the open circuit voltage.
Step S202 determines the current residual capacity of each battery cell according to the OCV-SOC characteristic curve, and can directly determine the current residual capacity of the battery cell according to the OCV-SOC characteristic curve for the battery cell with the open circuit voltage in the capacity mappable interval in the OCV-SOC characteristic curve. Regarding a battery cell with the open-circuit voltage in a capacity unmapped section in the OCV-SOC characteristic curve, taking the lower limit residual capacity corresponding to the capacity unmapped section with the open-circuit voltage of the battery cell as the current residual capacity; taking the OCV-SOC characteristic curve of fig. 1 as an example, if the open-circuit voltage of the cell is 3.3V, the corresponding residual capacity interval is 30% -50%, and the lower limit residual capacity is 30%, then 30% is taken as the current residual capacity corresponding to the cell. In short, since the accurate residual capacity of the battery cell in the capacity non-mappable interval cannot be accurately determined, the minimum residual capacity corresponding to the capacity non-mappable interval is selected as the current residual capacity, so that the battery cell is prevented from being excessively discharged during battery equalization.
After determining the current residual capacity of the battery cell monomer of each battery cell monomer, taking the battery cell monomer with the current residual capacity being larger than the balance target capacity as the balance battery cell monomer, and discharging the balance battery cell monomer to change the residual capacity of the balance battery cell monomer to the balance target capacity. And then controlling the balanced discharge time of each balanced cell monomer, and realizing balanced discharge operation of the balanced cell monomers by setting the balanced discharge time.
In a power battery pack of an electric automobile, an equalization action is generally executed by a battery management system in the electric automobile, an equalization channel is integrated on a sampling channel of each battery cell on hardware, a resistor for consuming electric quantity of the battery cell and a MOSFET for switching the channel exist on the equalization channel, when the battery cell is subjected to equalization discharge, the MOSFET corresponding to the battery cell is turned on, and the electric quantity of the battery cell is consumed by the on resistor; and controlling the MOSFET to be conducted according to the balanced discharge time, so as to control the discharge time of the battery cell monomer.
When the equalization operation is executed, for the cell unit with the open-circuit voltage in the capacity unmapped interval in the OCV-SOC characteristic curve, the lower limit residual capacity corresponding to the capacity unmapped interval with the open-circuit voltage is used as the current residual capacity of the cell unit, so that whether the cell unit is the equalization cell unit needing to be discharged and the corresponding equalization discharge time are judged, the purpose of balancing the battery can be achieved, and the occurrence of reaction caused by overdischarge of the cell unit in the capacity unmapped interval can be avoided.
In one embodiment, the determining the equalization target capacity specifically includes:
acquiring an open-circuit voltage of each cell unit, and selecting the cell unit with the open-circuit voltage in a capacity mappable interval in an OCV-SOC characteristic curve as a reference cell unit;
determining the current residual capacity of each reference cell unit according to an OCV-SOC characteristic curve;
determining a preset number of reference cell monomers with lower current residual capacity as target cell monomers;
and calculating the current residual capacity average value of the target battery cell monomer as an equilibrium target capacity.
Specifically, firstly, a cell monomer with an open-circuit voltage in a capacity mappable interval in an OCV-SOC characteristic curve is selected as a reference cell monomer, and the current residual capacity of the reference cell monomer is determined. And sequencing the reference cell monomers according to the current residual capacity, selecting a preset number of reference cell monomers with lower current residual capacity as target cell monomers, and calculating the average value of the current residual capacities of all the target cell monomers as an equalization target capacity. The preset number may be set to 3 or more.
According to the embodiment of the application, the battery cell monomer with the open-circuit voltage in the capacity mappable interval is selected as the reference battery cell monomer, the reference battery cell monomer can obtain accurate current residual capacity, the balance target capacity of battery balance operation is determined according to the reference battery cell, and the obtained balance target capacity is accurate and reasonable.
In one embodiment, before the responding to the battery equalization operation is triggered, the method further comprises:
if the real-time battery pack electric quantity is within the preset balanced electric quantity range, the open-circuit voltage corresponding to the preset balanced electric quantity range is a capacity mappable interval in the OCV-SOC characteristic curve, and/or
The lowest temperature of the battery pack is greater than or equal to a preset temperature threshold, and/or
And starting the vehicle after the standing time of the battery pack is greater than or equal to the preset standing time, and triggering the battery balancing operation.
Specifically, the battery needs to allow battery equalization operations when set conditions are satisfied:
firstly, the real-time battery pack electric quantity is in a preset balance electric quantity range, and an open circuit voltage range corresponding to the preset balance electric quantity range is a capacity mappable interval in an OCV-SOC characteristic curve. Taking the OCV-SOC characteristic curve of fig. 1 as an example, the preset equalization amount range may be set to 30% or less. When the battery pack electric quantity is in a preset balance electric quantity range, the battery capacity of most of the battery core monomers in the battery pack is about the preset balance electric quantity range, so that the accurate current residual capacity can be ensured to be matched with most of the battery core monomers, and a better battery balance effect is achieved.
And secondly, the lowest temperature of the battery pack is above a preset temperature threshold. The temperature of each battery cell in the battery pack or the temperature of different areas is obtained, wherein the lowest temperature is the lowest temperature of the battery pack. Since the OCV-SOC characteristic curve of the battery varies due to the influence of the temperature condition, the OCV-SOC characteristic curve in the normal temperature range is generally used in practical engineering applications, and is not suitable for low temperature conditions, in order to avoid inaccurate battery capacity determined according to the preset OCV-SOC characteristic curve at low temperature, a preset temperature threshold is set, and is generally set to 18-23 ℃, and when the lowest temperature of the battery pack is greater than or equal to the preset temperature threshold, the battery equalization operation is allowed.
Thirdly, starting the vehicle after the standing time of the battery pack is more than or equal to the preset standing time. In the use process of the battery pack, chemical reaction can be generated in the battery due to the effects of various factors such as charge and discharge, temperature, use time and the like. If these chemical reactions are not balanced, the calculation of the remaining capacity of the battery may be inaccurate. Therefore, the battery is kept still for a preset standing time period to balance the internal reaction, so that the more accurate residual capacity can be obtained by determining, and the effectiveness of the balancing operation is ensured. Wherein the preset rest time period is at least set to 1 hour.
In one embodiment, the battery equalization control method further includes:
in response to the completion of battery pack charging, selecting a cell unit with an open-circuit voltage greater than or equal to a preset open-circuit voltage as an equalization cell unit, wherein the preset open-circuit voltage is in a capacity mappable interval in an OCV-SOC characteristic curve;
determining the residual capacity corresponding to the preset open-circuit voltage as an equalization target capacity according to an OCV-SOC characteristic curve, and the current residual capacity of each equalization battery cell;
and determining the balanced discharge time of each balanced cell unit according to the current residual capacity and the balanced target capacity of each balanced cell unit, and controlling each balanced cell unit to discharge the balanced discharge time.
Specifically, the battery pack is charged, a battery cell monomer with an open-circuit voltage greater than or equal to a preset open-circuit voltage is selected as an equalization battery cell monomer, and the residual capacity corresponding to the preset open-circuit voltage is used as an equalization target capacity. Taking the OCV-SOC characteristic curve of fig. 1 as an example, the preset open circuit voltage may be set to an open circuit voltage corresponding to 99% of the remaining capacity, and the equalization target capacity is 99%. And then controlling the balance battery cell unit to discharge until the residual capacity is 99%, and completing the battery balance operation.
According to the battery pack balancing method and device, battery balancing is performed after battery pack charging is completed, the times of battery pack balancing operation are increased, and the situation that the battery pack cannot perform balancing operation for a long time due to the fact that the battery pack does not meet balancing conditions is avoided.
In one embodiment, the determining the balanced discharge time of each balanced cell unit according to the current remaining capacity and the balanced target capacity of each balanced cell unit specifically includes:
calculating a capacity difference value between the current residual capacity and the balance target capacity;
the equilibrium discharge time is calculated according to the following formula:
T=ΔSOC*S/I，
wherein T is balanced discharge time, delta SOC is the capacity difference, S is the nominal capacity of the battery cell unit, I is balanced effective current, the balanced effective current is obtained by testing the whole battery pack in advance, the whole battery pack is controlled to run under NEDC standard endurance working condition, the battery pack is controlled to perform balanced operation in the running process, the current integral of the real-time balanced current and the running time of at least one sample battery cell unit is obtained, the monomer balanced current of each sample battery cell unit is calculated by dividing the current integral by the running time, and the average value of the monomer balanced currents of all sample battery cell units is calculated as the balanced effective current of the battery pack; preferably, a whole vehicle test can be performed on at least two battery packs of the same battery, each battery pack correspondingly obtains an equilibrium effective current, an average value is calculated, and the average value is used as the equilibrium effective current of the battery.
According to the embodiment of the application, according to the capacity difference value between the current residual capacity and the balance target capacity of the balance battery cell monomers, the nominal capacity and the balance effective current of the battery cell monomers are combined, and the balance discharge time of each battery cell monomer is calculated.
In one embodiment, before the controlling each of the balanced cell units to discharge the balanced discharge time, the method further includes:
if the real-time battery pack capacity is greater than the lower limit balance capacity, and/or
The output current of the battery pack is smaller than the upper limit equalizing current
And controlling each balanced cell unit to discharge the balanced discharge time.
Before the battery cell monomer is controlled to discharge, judging whether the battery meets the balanced discharge condition, wherein the real-time battery pack electric quantity is larger than the lower limit balanced electric quantity, and the lower limit balanced electric quantity is set to be 5% -10% so as to prevent the battery cell monomer from excessively low electric quantity after discharge, and the safety of the battery pack is influenced; and secondly, the output current of the battery pack is smaller than the upper limit balanced current, the upper limit balanced current can be set to be 200A, when the input current of the battery pack is larger than the upper limit balanced current, the requirement of the vehicle is larger, the main task of the battery cell unit is to provide power for the vehicle, and at the moment, the battery cell unit is not allowed to perform balanced discharge.
In one embodiment, when the control is performed to discharge the balanced discharge time of each balanced cell unit, if the vehicle enters a sleep state, the current discharge progress is stored, and the discharge operation is continuously performed when the vehicle is awakened next time.
In the embodiment of the application, when the battery cell unit performs balanced discharge, if the discharge time does not reach the corresponding balanced discharge time, the vehicle is in a dormant state, the discharged time is subtracted from the balanced discharge time and is stored as new balanced discharge time, and after the vehicle is awakened next time, balanced discharge operation is continuously performed when the balanced discharge condition is met, so that the balanced discharge operation can be performed completely, and the effect of balancing the battery is achieved.
In one embodiment, when the controlling of the discharging of each balanced cell unit to the balanced discharging time is performed, if a new balanced discharging strategy is received, the discharging of each balanced cell unit to the balanced discharging time is controlled according to the new balanced discharging strategy.
As an example, if the battery pack capacity satisfies the equalization condition when 30% or less, an equalization discharge strategy is generated, but since the vehicle does not satisfy the rest time, the equalization discharge operation is not performed all the time, and during the waiting period for the equalization discharge operation to be performed, the user charges the vehicle and generates a new equalization discharge strategy after full charge, at this time, the cell unit is controlled to perform the equalization discharge operation according to the new equalization discharge strategy, and the two equalization discharge strategies cannot be overlapped, so that the over discharge of the battery is avoided and the equalization effect is ensured.
Fig. 3 is a flowchart of a battery equalization control method according to a preferred embodiment of the present application, taking a lithium iron phosphate battery as an example, and specifically includes:
step S301: if the real-time battery pack capacity is below 30%, and/or
The minimum temperature of the battery pack is greater than or equal to 20 ℃, and/or
The standing time of the battery pack is more than or equal to 1 hour, and then the battery balancing operation is triggered;
step S302: acquiring an open circuit voltage of each cell unit, and selecting the cell units with the open circuit voltage of 0% -30% and 99% -100% as reference cell units;
step S303: determining the current residual capacity of each reference cell unit according to an OCV-SOC characteristic curve;
step S304: determining 3 reference cell monomers with lower current residual capacity as target cell monomers;
step S305: calculating the current residual capacity average value of the target battery cell monomer as an equilibrium target capacity;
step S306: determining the current residual capacity of each cell unit according to the OCV-SOC characteristic curve, determining the cell unit with the current residual capacity higher than the balance target capacity as the balance cell unit, wherein for the cell unit with the open circuit voltage of about 3.3V, determining the current residual capacity of the cell unit to be 30%, and then executing steps S309-S310;
step S307: responding to the completion of battery pack charging, and selecting a battery cell monomer with an open-circuit voltage greater than or equal to 3.34V as an equalization battery cell monomer;
step S308: determining 99% of the residual capacity corresponding to 3.34V as an equalization target capacity, determining the current residual capacity of each equalization battery cell according to the OCV-SOC characteristic curve, and then executing steps S309-S310;
step S309: determining the balanced discharge time of each balanced cell unit according to the current residual capacity and the balanced target capacity of each balanced cell unit;
step S310: if the real-time battery pack capacity is greater than 5%, and/or
The output current of the battery pack is less than 200A
And controlling each balanced cell unit to discharge the balanced discharge time.
If the vehicle enters a sleep state during the execution of step S310, the current discharging progress is stored and the execution is continued when the vehicle is awakened next time; if a new balanced discharge strategy is received, step S310 is performed according to the new balanced discharge strategy.
The technical solution of the present application also provides a storage medium storing computer instructions for executing the battery equalization control method in any of the foregoing embodiments when the computer executes the computer instructions.
Fig. 4 shows an electronic device of the present application, comprising:
at least one processor 401; the method comprises the steps of,
a memory 402 communicatively coupled to the at least one processor 401; wherein,
the memory 402 stores instructions executable by the at least one processor 401 to enable the at least one processor 401 to perform all the steps of the battery equalization control method in any of the method embodiments described above.
In fig. 4, a processor 401 is taken as an example:
the electronic device may further include: an input device 403 and an output device 404.
The processor 401, memory 402, input device 403, and output device 404 may be connected by a bus or other means, which is illustrated as a bus connection.
The memory 402 is used as a non-volatile computer readable storage medium, and may be used to store a non-volatile software program, a non-volatile computer executable program, and modules, such as program instructions/modules corresponding to the battery balancing control method in the embodiment of the present application, for example, the method flow shown in fig. 2 or 3. The processor 401 executes various functional applications and data processing by running nonvolatile software programs, instructions, and modules stored in the memory 402, that is, implements the battery equalization control method in the above-described embodiment.
Memory 402 may include a storage program area that may store an operating system, at least one application program required for functionality, and a storage data area; the storage data area may store data created according to the use of the battery equalization control method, and the like. In addition, memory 402 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 402 may optionally include memory remotely located with respect to processor 401, which may be connected via a network to a device performing the battery equalization control method. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The input device 403 may receive input user clicks and generate signal inputs related to user settings and function control of the battery equalization control method. The output 404 may include a display device such as a display screen.
The battery equalization control method of any of the method embodiments described above is performed when executed by the one or more processors 401, with the one or more modules stored in the memory 402.
What has been described above is merely illustrative of the principles and preferred embodiments of the present application. It should be noted that, for a person skilled in the art, embodiments which are obtained by appropriately combining the technical solutions respectively disclosed in the different embodiments are also included in the technical scope of the present invention, and that several other modifications are possible on the basis of the principles of the present application and should also be regarded as the protection scope of the present application.
Claims (8)
1. A battery equalization control method, characterized by comprising:
determining an equalization target capacity in response to a battery equalization operation being triggered;
determining the current residual capacity of each cell unit according to an OCV-SOC characteristic curve, and determining the cell unit with the current residual capacity higher than the balance target capacity as the balance cell unit, wherein for the cell unit with the open-circuit voltage in a capacity non-mappable interval in the OCV-SOC characteristic curve, the lower limit residual capacity corresponding to the capacity non-mappable interval in which the open-circuit voltage of the cell unit is positioned is taken as the current residual capacity;
determining the balanced discharge time of each balanced cell unit according to the current residual capacity and the balanced target capacity of each balanced cell unit, and controlling each balanced cell unit to discharge the balanced discharge time;
before the response to the battery equalization operation is triggered, further comprising:
if the real-time battery pack electric quantity is within the preset balanced electric quantity range, the open-circuit voltage corresponding to the preset balanced electric quantity range is a capacity mappable interval in the OCV-SOC characteristic curve, and/or
The lowest temperature of the battery pack is greater than or equal to a preset temperature threshold, and/or
After the standing time of the battery pack is longer than or equal to the preset standing time, starting the vehicle, and triggering the battery balancing operation;
the battery equalization control method further comprises the following steps:
in response to the completion of battery pack charging, selecting a cell unit with an open-circuit voltage greater than or equal to a preset open-circuit voltage as an equalization cell unit, wherein the preset open-circuit voltage is in a capacity mappable interval in an OCV-SOC characteristic curve and is an open-circuit voltage corresponding to 99% of residual capacity;
determining the residual capacity corresponding to the preset open-circuit voltage as an equalization target capacity according to an OCV-SOC characteristic curve, and the current residual capacity of each equalization battery cell;
and determining the balanced discharge time of each balanced cell unit according to the current residual capacity and the balanced target capacity of each balanced cell unit, and controlling each balanced cell unit to discharge the balanced discharge time.
2. The battery equalization control method according to claim 1, wherein said determining an equalization target capacity specifically comprises:
acquiring an open-circuit voltage of each cell unit, and selecting the cell unit with the open-circuit voltage in a capacity mappable interval in an OCV-SOC characteristic curve as a reference cell unit;
determining the current residual capacity of each reference cell unit according to an OCV-SOC characteristic curve;
determining a preset number of reference cell monomers with lower current residual capacity as target cell monomers;
and calculating the current residual capacity average value of the target battery cell monomer as an equilibrium target capacity.
3. The battery equalization control method according to claim 1, wherein the determining the equalization discharge time of each of the equalization cells according to the current remaining capacity and the equalization target capacity of each of the equalization cells specifically comprises:
calculating a capacity difference value between the current residual capacity and the balance target capacity;
the equilibrium discharge time is calculated according to the following formula:
T=ΔSOC*S/I，
wherein T is the balanced discharge time, delta SOC is the capacity difference, S is the nominal capacity of the battery cell, and I is the balanced effective current.
4. The battery equalization control method of claim 1, wherein prior to said controlling each of said equalization cells to discharge said equalization discharge time, further comprising:
if the real-time battery pack capacity is greater than the lower limit balance capacity, and/or
The output current of the battery pack is smaller than the upper limit equalizing current
And controlling each balanced cell unit to discharge the balanced discharge time.
5. The battery equalization control method according to claim 1, wherein when the control of discharging the equalization cells for the equalization discharge time is performed, if the vehicle enters a sleep state, a current discharge progress is stored and a discharge operation is continued when the vehicle is awakened next time.
6. The battery equalization control method of claim 1, wherein when said controlling each of said equalization cells to discharge said equalization discharge time is performed, if a new equalization discharge strategy is received, each of said equalization cells is controlled to discharge said equalization discharge time according to said new equalization discharge strategy.
7. A storage medium storing computer instructions which, when executed by a computer, are adapted to carry out the battery equalization control method of any of claims 1-6.
8. An electronic device comprising at least one processor; the method comprises the steps of,
a memory communicatively coupled to the at least one processor; wherein,
the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the battery equalization control method of any of claims 1-6.
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