CN112909362B - Cell voltage correction method, device, equipment and medium - Google Patents

Cell voltage correction method, device, equipment and medium Download PDF

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Publication number
CN112909362B
CN112909362B CN202110155156.7A CN202110155156A CN112909362B CN 112909362 B CN112909362 B CN 112909362B CN 202110155156 A CN202110155156 A CN 202110155156A CN 112909362 B CN112909362 B CN 112909362B
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current
module
voltage
cross
master
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CN112909362A (en
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王杰炜
王险峰
李红星
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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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
    • H01M10/4285—Testing apparatus
    • 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 method, a device, equipment and a medium for correcting cell voltage. The method comprises the following steps: acquiring first current of a master module and a slave module and first voltage of each battery cell under the first current; calculating a first sampling voltage difference based on the first voltage of each cell; determining a second current meeting the trigger condition with the first current, and acquiring a second voltage of each battery cell under the second current; calculating a second sampling voltage difference according to the second voltage of each battery cell; obtaining a correction resistance value of the cross-module connecting piece according to the first current, the second current, the first sampling pressure difference and the second sampling pressure difference; calculating a current compensation pressure difference across the module connectors; and acquiring the current sampling voltage of the cross-module battery cell influenced by the cross-module connecting piece in the master-slave module under the current to obtain the current correction voltage of the cross-module battery cell. The cell voltage correction method, the device, the equipment and the medium provided by the embodiment of the invention realize correction of the cross-module cell acquisition voltage.

Description

Cell voltage correction method, device, equipment and medium
The application is a divisional application provided by the invention with the application number of 201811201749.7, the application date of 2018, 10, 16 and the name of cell voltage correction method, device, equipment and medium.
Technical Field
The invention relates to the field of new energy, in particular to a method, a device, equipment and a medium for correcting cell voltage.
Background
In the battery management system, the connection mode between the battery modules may be a master-slave connection mode, which is called master-slave module. The master-slave module is usually a master with a slave, the master control board is located on the master module, and the slave module has no control board. The master module and the slave module are connected with the cascade wire harness through a cross-module connecting piece. Because there is a certain impedance across the module connector, when a large current flows, a voltage drop occurs across the module connector.
And under the master-slave connection mode, the battery cell connected with the cross-module connecting piece in the slave module is a cross-module battery cell. When sampling the cross-module cell, the cross-module connector and the cross-module cell are generally integrated. At this moment, the sampling voltage across the module electric core can be influenced by the cross-module connecting piece, so that the voltage of the battery pack is large when the battery pack is charged, and the voltage is small when the battery pack is discharged.
Due to the existence of the voltage drop of the cross-module connecting piece, the voltage sampling of the cross-module battery cell is affected, so that the calculation of the State of Charge (SOC) of the cross-module battery cell is not accurate, and other problems related to the SOC of the cross-module battery cell are caused, and therefore the sampling voltage of the battery cell affected by the cross-module connecting piece needs to be corrected.
Disclosure of Invention
The cell voltage correction method, the device, the equipment and the medium provided by the embodiment of the invention realize correction of the acquired voltage of the cross-module cell influenced by the cross-module connecting piece.
According to an aspect of an embodiment of the present invention, there is provided a cell voltage correction method, including:
calculating a corrected resistance value of a cross-module connecting piece in the master-slave module based on the acquired first current of the master-slave module, the first voltage of each battery cell in the master-slave module under the first current, the second current of the master-slave module and the second voltage of each battery cell in the master-slave module under the second current;
calculating the current compensation pressure difference of the cross-module connecting piece according to the corrected resistance value and the acquired current of the master module and the slave module;
acquiring the current sampling voltage of a cross-module battery cell influenced by a cross-module connecting piece in a master-slave module under the current, and correcting the current sampling voltage based on the current compensation pressure difference to obtain the current correction voltage of the cross-module battery cell;
the first current and the second current meet a preset trigger condition, the trigger condition is that a current difference value between the first current and the second current meets a preset threshold value, and the second current is stable in a preset time period.
According to another aspect of the embodiments of the present invention, there is provided a cell voltage correction apparatus, including:
the resistance calculation module is used for calculating a corrected resistance value of a cross-module connecting piece in the master-slave module based on the acquired first current of the master-slave module, the first voltage of each battery cell in the master-slave module under the first current, the second current of the master-slave module and the second voltage of each battery cell in the master-slave module under the second current;
the compensation pressure difference calculation module is used for calculating the current compensation pressure difference of the cross-module connecting piece according to the corrected resistance value and the acquired current of the master module and the slave module;
the correction module is used for acquiring the current sampling voltage of the cross-module battery cell influenced by the cross-module connecting piece in the master-slave module under the current, and correcting the current sampling voltage based on the current compensation pressure difference to obtain the current correction voltage of the cross-module battery cell;
the first current and the second current meet a preset trigger condition, the trigger condition is that a current difference value between the second current and the first current meets a preset threshold value, and the second current is stable in a preset time period.
According to still another aspect of the embodiments of the present invention, there is provided a cell voltage correction apparatus, including:
a memory for storing a program;
and the processor is used for operating the program stored in the memory so as to execute the cell voltage correction method provided by the embodiment of the invention.
According to a further aspect of the embodiments of the present invention, there is provided a computer-readable storage medium, on which computer program instructions are stored, wherein the computer program instructions, when executed by a processor, implement the cell voltage correction method according to the embodiments of the present invention.
According to the method, the device, the equipment and the medium for correcting the cell voltage, provided by the embodiment of the invention, the correction resistance value of the cross-module connecting piece is obtained by utilizing the first current and the second current of the master-slave module which meet the preset trigger condition and the second voltage of each cell under the first current and the second current of each cell in the master-slave module under the first current, and the real-time correction of the corrected cross-module cell collected voltage is realized according to the correction resistance value.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly described below, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a master-slave module according to an embodiment of the present invention;
fig. 2 illustrates a flow diagram of a method of cell voltage correction provided in accordance with some embodiments of the present invention;
fig. 3 is a schematic structural diagram of a cell voltage correction apparatus according to some embodiments of the present invention;
fig. 4 is a schematic diagram illustrating a hardware structure of a cell voltage correction apparatus according to some embodiments of the present invention.
Detailed Description
Features and exemplary embodiments of various aspects of the present invention will be described in detail below, and in order to make objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention. It will be apparent to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
First, a cell voltage correction method provided by an embodiment of the present invention is described in detail with reference to the accompanying drawings.
Fig. 1 is a schematic structural diagram of a master-slave module 100 according to an exemplary embodiment of the invention. As shown in fig. 1, the master-slave module includes a master module 101 having a Micro Controller Unit (MCU) and a slave module 102 without a MCU. The master module 101 and the slave module 102 are connected by a cross-module connection 103 and a cascade harness. The main module 101 includes 6 battery cells, i.e., C1 to C6. The slave module 102 includes 6 battery cells, i.e., C7-C12. The number of the battery cells in the master module and the number of the battery cells in the slave module are not specifically limited in the embodiments of the present invention.
The battery cell C7 connected to the cross-module connector 103 in the slave module 102 is a cross-module battery cell. The current sensor 104 is used for collecting the current of the master module and the slave module. Temperature sensors 105 and 106 are used to collect the temperature across the module connector 103.
The MCU in the master module 101 needs to acquire voltage data of 12 cells in the master module 101 and the slave module 102, and in addition, the voltage drop across the module connector 103 requires 13 sampling nodes. However, there are only 12 voltage sampling channels for many sampling chips in the market, and in order to meet sampling requirements, the cross-module connecting piece 103 and the battery cell C7 need to be taken as a whole as a battery cell. At this time, the sampling voltage across the module cell C7 is affected by the cross-module connection part 103, which causes the voltage of the battery pack to be large during charging and small during discharging.
The acquired voltage across the module cell C7 is the voltage V between the port a and the port B in fig. 1AB. The a port is a common port between the cell C6 and the cross-module connector 103, and the B port is a common port between the cell C7 and the cell C8. Also can be usedThat is, the collected voltage V across the module cell C7ABIs the voltage across the module connector 103 and the cell C7.
In order to correct the voltage across the module cell, an embodiment of the present invention provides a cell voltage correction method. Fig. 2 is a schematic flow chart of a cell voltage correction method according to an embodiment of the present invention. As shown in fig. 2, a cell voltage correction method 200 in the embodiment of the present invention includes the following steps:
s210, calculating a corrected resistance value of the cross-module connecting piece in the master module and the slave module based on the acquired first current of the master module and the slave module, the first voltage of each battery cell in the master module and the slave module under the first current, the second current of the master module and the slave module and the second voltage of each battery cell in the master module and the slave module under the second current.
In the embodiment of the invention, the cross-module connecting piece in the master module and the slave module can be a copper bar.
In the embodiment of the present invention, the self-factors of the master module and the slave module, such as the material of the cross-module connecting member in the master module and the slave module, the direct current resistance of the battery cells in the master module and the slave module, the installation mode of the master module and the slave module, and the layout of the sampling points in the master module and the slave module, may affect the calculation of the resistance value of the cross-module connecting member. In other words, the calculation of the cross-module connector resistance in each master-slave module is interfered by the factors of each master-slave module.
In the embodiment of the present invention, for the cross-module connecting pieces in different master-slave modules, the calculation of the resistance value of the cross-module connecting piece in different master-slave modules can be realized according to the obtained first current of each master-slave module, the first voltage of each battery cell under the first current of each master-slave module, the second current of each master-slave module, and the second voltage of each battery cell under the second current of each master-slave module. That is to say, the resistance value of the cross-module connecting piece in each master-slave module can be respectively calculated according to the current and the cell voltage of each master-slave module, so that the interference of the factors of the master-slave module to the calculation of the resistance value of the cross-module connecting piece can be avoided, and the method has better adaptability.
In the embodiment of the invention, the calculation of the resistance value of the cross-module connecting piece is not only influenced by the factors of the master module and the slave module, but also influenced by the application environment of the master module and the slave module.
As an example, charging device parameters for the cells in the master-slave module, such as charging device parameters in a 4S store, may have an effect on the charging current of the cells in the master-slave module. Different temperatures in different regions can cause different temperatures of the environment where the battery cell is located, and the environment temperature of the battery cell can affect both the charging current and the discharging current of the battery cell. In addition, the cell temperature also affects the current of the cell. Because the calculation of the resistance value of the cross-module connecting piece needs to utilize the electric core current, the application environment of the master module and the slave module can also influence the calculation of the resistance value of the cross-module connecting piece. It should be noted that the current of the master module and the slave module is the current of the battery cells in the master module and the slave module.
Therefore, in order to avoid the influence of environmental factors on the calculation of the resistance value of the cross-module connection element and improve the adaptivity of the calculation of the resistance value of the cross-module connection element, the first current and the second current need to be set to meet a preset trigger condition. The preset trigger condition is that a current difference value between the first current and the second current meets a preset threshold value, and the second current is stable in a preset time period.
The triggering conditions of the first current and the second current are set according to a preset corresponding relation between the battery cell temperature and the battery cell current, charging equipment parameters of the battery cell and the temperature of the environment where the battery cell is located. For different master and slave modules, the threshold value of the current difference value of the first current and the second current and the stable time period value of the second current can be set according to actual application requirements and application scenes.
S220, calculating the current compensation pressure difference of the cross-module connecting piece according to the corrected resistance value and the collected current of the master module and the slave module.
In an embodiment of the invention, the present compensation differential pressure Δ V across the modular connection is equal to the product of the corrected resistance value across the modular connection and the present current of the master and slave modules. The current of the master module and the slave module can be obtained from the current sensor of the master module and the slave module. The current compensated differential pressure Δ V across the module connection is the differential pressure across the module connection.
As one example, the current of the master and slave modules in the vehicle changes in real time during the operation of the vehicle. According to the current of the master module and the slave module of the vehicle and the calculated correction resistance value of the cross-module connecting piece, the current compensation differential pressure of the cross-module connecting piece can be obtained, so that the real-time correction of the cross-module battery core voltage is realized.
And S230, acquiring the current sampling voltage of the cross-module battery cell influenced by the cross-module connecting piece in the master-slave module at the current, and correcting the current sampling voltage based on the current compensation pressure difference to obtain the current correction voltage of the cross-module battery cell.
In the embodiment of the invention, if the master module and the slave module can meet the requirement of having stable large charging current for a continuous period of time, namely the master module and the slave module can carry out quick charging, the static current and the charging current of the master module and the slave module can be utilized to calculate the correction resistance value of the cross-module connecting piece. That is, the first current is the quiescent current of the master/slave module, and the second current is the charging current of the master/slave module.
The static current is a small current of the master module and the slave module under a static working condition, namely, the self-consumed current of the master module and the slave module under the condition that the master module and the slave module are not influenced by external factors.
In the embodiment of the invention, when the master module and the slave module perform quick charging, the correction resistance value of the cross-module connecting piece can also be calculated by using the two charging currents of the master module and the slave module which meet the triggering condition.
When the correction resistance value of the cross-module connecting piece is calculated by using the static current and the charging current, or calculated by using two charging currents of the master module and the slave module which meet the triggering condition, the current correction voltage of the cross-module battery cell is the difference value obtained by subtracting the current compensation differential pressure of the cross-module connecting piece from the current sampling voltage of the cross-module battery cell.
In an embodiment of the present invention, as the lifetime of the master/slave module increases, the resistance across the module connector may degrade due to wear. In order to confirm the attenuation condition of the resistance value of the cross-module connecting piece in time, when the main module and the slave module meet the preset service time and the main module and the slave module do not carry out quick charging in the preset time period after the preset service time is met, the corrected resistance value of the cross-module connecting piece is calculated by using the discharge current of the main module and the slave module meeting the triggering condition.
As one example, the usage time of the master-slave module in the vehicle may be expressed by the mileage of the vehicle. And when the driving mileage of the vehicle reaches the preset mileage, judging whether the vehicle is subjected to quick charging within a preset time period after reaching the preset mileage.
And if the vehicle is charged quickly within a preset time period, calculating the correction resistance value of the cross-module connecting piece by using the static current and the charging current of the master module and the slave module which meet the triggering condition or the two charging currents of the master module and the slave module which meet the triggering condition.
If the vehicle is not charged quickly in a preset time period, the corrected resistance value of the cross-module connecting piece is calculated in time to confirm the attenuation condition of the resistance value of the cross-module connecting piece, and the corrected resistance value of the cross-module connecting piece is calculated by using the discharging current of the master module and the slave module which meet the triggering condition. That is, the first current and the second current are both discharge currents of the master module and the slave module.
It should be noted that the number of the preset mileage of the vehicle may be multiple. As an example, the preset mileage may be 5000 km, 5050 km, 5100 km, 5150 km … … 100000 km.
And when the driving mileage of the vehicle is less than 5000 kilometers of the minimum preset mileage, calculating the correction resistance value of the cross-module connecting piece by using the static current and the charging current of the master module and the slave module which meet the triggering condition when the vehicle is charged quickly.
When the driving mileage of the vehicle reaches any preset mileage in the above examples, whether the vehicle is subjected to quick charging within a preset time period after reaching the preset mileage is judged, so that whether the charging current of the master module and the slave module or the discharging current of the master module and the slave module is adopted to calculate the correction resistance value of the cross-module connecting piece is determined.
When the corrected resistance value of the cross-module connecting piece is calculated by using the discharge current of the master module and the slave module, the current corrected voltage of the cross-module battery cell is the sum of the current sampling voltage of the cross-module battery cell and the current compensation differential pressure of the cross-module connecting piece.
In the embodiment of the invention, before the driving mileage of the vehicle does not reach the preset mileage, the static current and the charging current of the master module and the slave module which meet the triggering condition or the two charging currents of the master module and the slave module which meet the triggering condition can be used for calculating the corrected resistance value of the cross-module connecting piece.
It is worth mentioning that before the driving mileage of the vehicle does not reach the preset mileage, the discharging current of the master module and the slave module can be used for calculating the correction resistance value of the cross-module connecting piece. In other words, before the driving mileage of the vehicle does not reach the preset mileage, when the vehicle is charged quickly, the correction resistance value of the cross-module connecting piece can be calculated by using the quiescent current and the charging current of the master-slave module or the two charging currents of the master-slave module meeting the triggering condition; when the vehicle is running, the corrected resistance value of the cross-module connecting piece can be calculated by using the discharge current of the master module and the slave module which meet the triggering condition.
According to the cell voltage correction method provided by the embodiment of the invention, the correction resistance value of the cross-module connecting piece is calculated by using the first current and the second current which meet the trigger condition, and the voltage of each cell under the first current and the voltage of each cell under the second current, and the correction of the cross-module cell acquisition voltage is realized by using the correction resistance value of the cross-module connecting piece.
The calculation of the resistance of the cross-module connector will be described in detail below by taking the first current as a quiescent current and the second current as a charging current.
In an embodiment of the present invention, when the first current is a static current and the second current is a charging current, the step S210 specifically includes the following steps:
s2101 obtains the static current and the first voltage of each cell under the static current.
As one example, the battery pack in the vehicle includes a master-slave module, and the battery modules in the battery pack are all connected in series, i.e., the current of the battery pack is the current of the master-slave module. Therefore, the quiescent current Is of the master module and the slave module can be obtained from the current sensor of the battery pack. The first voltage for each cell in the master-slave module may be obtained from an MCU of a cell management unit in a battery management system of the vehicle.
As a specific example, referring to fig. 1, the voltage of each of the 12 cells in the master-slave module under the quiescent current may be obtained from the MCU in the master module.
The low-voltage side power supply can be used for supplying power to devices such as a current sensor and a battery cell management unit in the battery management system so as to obtain the voltage of each battery cell in the master-slave module under the Is and the Is of the master-slave module.
S2102 of calculating a first sampling differential pressure based on the first voltage of each cell, where the first sampling differential pressure is a difference between a first voltage across the module cells and an average of first voltages of all cells except the module cells in the master-slave module.
As an example, with continued reference to fig. 1, the voltage V of the cross-module cell C7 under Is calculated according to the voltage of each of the 12 cells in the master-slave module under Is7And the average value V of the voltages of the 11 cells except the cell C7 in the master-slave module under IsavgDifference Δ V betweend。ΔVdThe cell intrinsic differential pressure due to the cell inconsistency, that is, the first sampling differential pressure. Wherein the voltage V of the cross-module cell C7 under Is7I.e. the voltage between the a-port and the B-port, taken under the condition Is.
S2103, determining a charging current satisfying the trigger condition with the quiescent current, and obtaining a second voltage of each battery cell under the charging current.
In the embodiment of the invention, when the master module and the slave module are charged, the charging current of the master module and the slave module Is continuously collected, and the collected charging current Is compared with the Is until the charging current meeting the trigger condition with the Is obtained. And after the charging current Ic meeting the trigger condition with the Is obtained, acquiring a second voltage of each battery cell in the master-slave module under the Ic.
As an example, the trigger condition is that the current difference of the quiescent current and the charging current is 100 amperes (a), and the current difference is continuously stable for 6 seconds. That is, the charging current was stable for 6 seconds. As a specific example, the quiescent current of the master/slave module is 1A, and if the charging currents of the master/slave module collected within 6 seconds are all 101A, it is considered that the quiescent current 1A and the charging current 101A satisfy the trigger condition. And when the charging current meeting the trigger condition with the static current is determined, acquiring a second voltage of each battery cell in the master-slave module under 101A.
S2104, calculating a second sampling differential pressure according to the second voltage of each cell, where the second sampling differential pressure is a difference between the second voltage across the module cell and an average of the second voltages of all cells in the master-slave module except the across-module cell.
With continued reference to fig. 1, based on the voltage of each of the 12 cells in the foregoing master-slave module at Ic, a voltage V of a cross-module cell C7 at Ic is calculated7' and the average value V of the voltages at Ic of the remaining 11 cells except the cell C7 in the master-slave moduleavg' difference between DeltaVb。ΔVbThen the sampling pressure differential affected by the cross-module connection. Wherein the voltage V of the cross-module cell C7 under Ic7', is the voltage between the A port and the B port collected under the condition of Ic.
And S2105, obtaining a corrected resistance value of the cross-module connecting piece according to the static current, the charging current, the first sampling pressure difference and the second sampling pressure difference.
In an embodiment of the present invention, S2105 includes the steps of:
and A, calculating a current difference value between the quiescent current and the charging current.
As an example, the current difference between the foregoing quiescent current Is and charging current Ic Is Ic-Is.
And B, obtaining a voltage difference value between the first sampling pressure difference and the second sampling pressure difference according to the first sampling pressure difference and the second sampling pressure difference.
As an example, the foregoing first sampled pressure differential Δ VdAnd a second sampled differential pressure Δ VbThe difference between the voltages is DeltaVb–ΔVd。
And C, calculating the absolute value of the ratio of the voltage difference value to the current difference value, and taking the absolute value as the correction resistance value of the cross-module connecting piece.
As an example, the corrected resistance value R of the cross-module connectorbThe calculation can be made using the following expression:
Figure BDA0002934452660000101
in an embodiment of the present invention, from S220, the current compensated pressure differential Δ V across the module connection may be calculated using the following expression:
ΔV＝Rb*Ip (2)
wherein Ip is the current Ip of the master module and the slave module.
In the embodiment of the present invention, according to S230, the corrected voltage V across the module cell can be knownrThe calculation can be made using the following expression:
Vr＝Vm-ΔV (3)
wherein, VmThe current Ip is the current that crosses the acquired voltage of the module cell.
As an example, for a master module and a slave module in a vehicle, when the driving mileage of the vehicle is less than the minimum preset mileage, or the driving mileage of the vehicle reaches the preset mileage and the quick charging is performed within a preset time period after the preset mileage is reached, the static current and the charging current of the master module and the slave module which meet the trigger condition are used to calculate the corrected resistance value of the cross-module connecting piece.
It should be noted that, when the vehicle is charged quickly, the correction voltage across the module electric core may also be calculated by using two charging currents meeting the trigger condition, and the specific calculation method is similar to the method for calculating the correction voltage across the module electric core by using the quiescent current and the charging current meeting the trigger condition in the above example, and is not described herein again.
However, when the driving mileage of the vehicle reaches the preset mileage and the vehicle is not charged quickly in the preset time period after reaching the preset mileage, in order to calculate the corrected resistance value of the cross-module connecting piece in time, the corrected resistance value of the cross-module connecting piece is calculated by adopting the discharging current of the master module and the slave module. That is, the first current and the second current are both discharge currents of the master module and the slave module.
The calculation of the resistance value of the cross-module connector will be described below by taking the first current and the second current as discharge currents as an example.
As an example, when it Is detected that the vehicle travels to a preset mileage, and the vehicle Is not rapidly charged within a preset time period after reaching the preset mileage, that Is, the resistance value of the cross-module connection Is not updated within the preset time period, the travel current of the vehicle, that Is, the first discharge current Is 'of the master-slave module Is continuously collected, and the voltage of each battery cell in the master-slave module under Is' Is collected.
As a specific example, the preset mileage of the vehicle is 5000 kilometers, and the vehicle is not fast charged within 48 hours after the vehicle travels to 5000 kilometers, that is, the resistance value of the cross-module connection part is not updated within 48 hours, and the travel current of the vehicle is continuously collected.
Then, according to the voltage of each battery cell in the master-slave module under Is', calculating a first sampling pressure difference delta V under Isd’。ΔVd' and the first sampling differential pressure DeltaV under the quiescent current IsdThe calculation method is similar and will not be described herein again.
It should be noted that before the second discharge current satisfying the trigger condition with Is' Is not collected, the correction resistance value of the cross-module battery cell voltage Is still corrected by using the correction resistance value of the cross-module connecting piece calculated according to the quiescent current and the charging current.
In the driving process of the vehicle, the collected discharging current of the master-slave module Is compared with the first discharging current Is 'until the second discharging current Ic' meeting the triggering condition with the first discharging current Is 'Is determined, and the voltage of each battery cell in the master-slave module under the Ic' Is collected.
Then, according to the voltage of each battery cell in the master-slave module under the Ic ', a second sampling pressure difference delta V under the Ic' is calculatedb’。ΔVb' calculation method and charging current IcSecond sampled differential pressure Δ VbThe calculation method is similar and will not be described herein again.
The current difference between the first discharge current Is 'and the second discharge current Ic' and the stable time period of the current difference may be set according to an actual application scenario.
In an embodiment of the present invention, a corrected resistance value across the module connector may be calculated using a method similar to step S2105. Correction resistance value R of cross-module connecting piecebThe calculation can be made using the following expression:
Figure BDA0002934452660000121
wherein, according to S230, the corrected voltage V of the cross-module battery cell can be knownrThe calculation can be made using the following expression:
Vr＝Vm+ΔV (5)
wherein, VmThe current Ip of the master-slave module is the acquisition voltage of the battery cell of the slave-slave module, Δ V ═ Rb*Ip。
It is worth mentioning that when the driving mileage of the vehicle reaches a certain preset mileage, the charging current of the master module and the slave module or the discharging current of the master module and the slave module is selected to be used for updating the corrected resistance value of the cross-module connecting piece according to whether the vehicle is subjected to quick charging within a preset time period after the driving mileage reaches the preset mileage.
If the vehicle is charged quickly within a preset time period after reaching a preset mileage, updating the correction resistance value of the cross-module connecting piece by using the charging current and the quiescent current meeting the trigger condition or two charging currents meeting the trigger condition; and if the vehicle is not charged quickly within a preset time period after reaching the preset mileage, updating the correction resistance value of the cross-module connecting piece by using the discharge current meeting the trigger condition.
In the embodiment of the invention, the corrected resistance value of the cross-module connecting piece is calculated under the charging condition or the discharging condition according to the use condition of the master module and the slave module, so that the accuracy of the calculation of the resistance value of the cross-module connecting piece is ensured.
In the embodiment of the invention, the complexity of the road condition of the vehicle in the driving process is considered, and the accuracy of calculating the resistance value of the cross-module connecting piece under the discharging condition is further improved. In some embodiments of the present invention, S210 comprises the steps of:
s2101-1, a plurality of pairs of currents of the master module and the slave module are obtained, and each pair of currents in the plurality of pairs of currents comprises a first current of the master module and a second current of the master module and the slave module which meet triggering conditions.
In the embodiment of the invention, in order to ensure the accuracy of the resistance value of the cross-module connecting piece calculated by using the discharge current, the resistance values to be corrected of the plurality of cross-module connecting pieces are calculated by using the discharge currents of a plurality of pairs of master modules and slave modules which meet the preset trigger condition. Each pair of discharge currents comprises a first discharge current and a second discharge current which meet a preset trigger condition.
S2102-1, calculating a plurality of resistance values to be corrected across the module connecting member based on the acquired first current of each pair of currents, the first voltage of each cell at the first current of each pair of currents, the second current of each pair of currents, and the second voltage of each cell at the second current of each pair of currents.
As a specific example, first of all, a first discharge current I of a first pair of discharge currents is obtained1And I1Voltage of each lower cell.
Then, based on I1Calculating a first sampling pressure difference delta V of the voltage of each lower battery cell1。ΔV1Is I1The voltage of the lower cross-module cell and all the cells except the cross-module cell in the master-slave module are in I1The difference between the average values of the lower voltages.
Then, determining the sum of1Second discharge current I satisfying trigger condition1', and obtaining I1Voltage of each cell, and according to I1' calculating a second sampling voltage difference DeltaV of the voltage of each lower battery cell1'. Wherein, is Δ V1' is a cross-module cell in I1Voltage at' with all cells in the master-slave module except the cross-module cells at I1' difference between average values of lower voltages.
Further, according to I1、I1’、ΔV1And Δ V1', obtaining a first resistance value R to be corrected of the cross-module connecting piece1. Wherein, a first resistance value R to be corrected of the cross-module connecting piece1The calculation method of (3) can refer to S2105, and is not described herein again.
Finally, R is calculated as described above using the first pair of discharge currents1And calculating the resistance value to be corrected of the corresponding cross-module connecting piece under each pair of discharge current conditions by a similar method.
It should be noted that, in step S2102-1, the resistance values to be corrected calculated according to the pairs of discharge currents are all the resistance values to be corrected of the same cross module connecting component. When the battery pack includes a plurality of master-slave modules, the method similar to that in step S2102-1 can be used for obtaining a plurality of resistance values to be corrected of the cross-module connecting members in each master-slave module for the cross-module connecting members in each master-slave module.
S2103-1, determining a correction resistance value of the cross-module connecting piece according to the resistance values to be corrected.
As an example, first, a maximum resistance value to be corrected and a minimum resistance value to be corrected among a plurality of resistance values to be corrected of the cross-module connecting member calculated from the plurality of pairs of discharge currents are removed; and then averaging the residual resistance values to be corrected after the maximum resistance value to be corrected and the minimum resistance value to be corrected are removed, and taking the obtained resistance average value as the correction resistance value of the cross-module connecting piece.
In the embodiment of the invention, the correction resistance value of the cross-module connecting piece can also be determined by using a filtering algorithm such as an arithmetic mean filtering method, a weighted recursive mean filtering method and the like.
In the embodiment of the invention, the number of the resistance values to be corrected, which need to be calculated, can be set according to the running environments of different vehicles, namely the number of times of triggering the resistance values to be corrected of the cross-module connecting piece is triggered and calculated. As an example, since the driving environment of the off-road vehicle is severe, the number of times of triggering of the off-road vehicle may be set to be larger than that of the home car when calculating the correction resistance value across the module connecting member.
According to the cell voltage correction method provided by the embodiment of the invention, voltage fluctuation caused by the cross-module connecting piece in the master module and the slave module is corrected by using the calculated correction resistance value of the cross-module connecting piece, so that the problem of inaccurate sampling voltage of the cross-module cell is solved.
In the embodiment of the invention, statistical analysis may be performed on the data according to a large range of sample measurement to obtain a fixed resistance value of the cross-module connecting member, and the voltage of the cross-module battery cell may be corrected by using the resistance value.
In some embodiments of the present invention, before S210, the cell voltage correction method further includes:
s200, collecting the temperature of two ends of the cross-module connecting piece.
As an example, as the service life of a vehicle increases, cross-module connections in the master and slave modules of the vehicle may become aged and loose, and thus, before calculating the corrected resistance value of the cross-module connections, it is necessary to determine that the cross-module connections are not faulty.
In the embodiment of the invention, whether faults such as aging, loosening and the like occur in the cross-module connecting piece can be judged according to the temperatures of the two ends of the cross-module connecting piece and the temperatures of the master module and the slave module.
As an example, referring to fig. 1, a first end of the cross-module connector is connected with the cell C6 in the main module. And selecting a first temperature sampling point at the first end of the cross-module connecting piece, and acquiring the temperature of the first temperature sampling point by using a temperature sensor. The temperature of the first temperature sampling point is the temperature of the first end of the cross-module connecting piece.
The second end of the cross-module connector is connected with the battery cell C7 in the slave module. And selecting a second temperature sampling point at the second end of the cross-module connecting piece, and acquiring the temperature of the second temperature sampling point by using the temperature sensor. And the temperature of the second temperature sampling point is the temperature of the second end of the cross-module connecting piece.
S201, determining that the temperatures at two ends of the cross-module connecting piece are smaller than the temperature threshold of the master module and the slave module.
In the embodiment of the invention, the temperature of the master module and the temperature of the slave module are the temperature collected by the temperature sensor at the temperature sampling point of the master module and the slave module. That is, the temperature of the master/slave module is the average temperature in the space of the master/slave module. The temperature of the master-slave module is also the cell temperature of all the cells included in the master-slave module.
If the temperatures at the two ends of the cross-module connecting piece are both smaller than the temperature threshold of the master module and the slave module, the cross-module connecting piece is free of faults, and the voltage of the battery cell influenced by the cross-module connecting piece can be corrected according to the methods from S210 to S230.
If the temperature of any one of the two ends of the cross-module connecting piece is greater than the temperature threshold of the master module and the slave module, or the temperatures of the two ends of the cross-module connecting piece are both greater than the temperature threshold of the master module and the slave module, the faults such as looseness or damage of the cross-module connecting piece are represented, and fault information is sent to the whole vehicle to inform risks.
According to the cell voltage correction method provided by the embodiment of the invention, before the correction resistance value of the cross-module connecting piece is calculated, whether the cross-module connecting piece has a fault is determined by using the temperatures at the two ends of the cross-module connecting piece and the temperature thresholds of the master module and the slave module, so that the fault monitoring of the cross-module connecting piece is realized.
In some embodiments of the present invention, the cell voltage correction method further includes:
and S240, calculating the attenuation degree of the cross-module connecting piece based on the corrected resistance value and the preset corresponding relation between the resistance value and the attenuation degree of the cross-module connecting piece.
As one example, wear may occur on the cross-module connections in the master and slave modules of the vehicle due to the continued use of the vehicle. That is, the resistance across the modular connector is constantly decaying. In order to ensure the normal operation of the vehicle, the resistance across the module connecting piece needs to be monitored to prevent the risk of excessive loss across the module connecting piece.
In the embodiment of the invention, when the correction resistance value of the cross-module connecting piece is calculated, the attenuation degree corresponding to the correction resistance value of the cross-module connecting piece can be obtained according to the corresponding relation between the pre-acquired resistance value of the cross-module connecting piece and the attenuation degree.
And S250, judging whether the cross-module connecting piece needs to be replaced or not based on the attenuation degree of the cross-module connecting piece and a preset attenuation degree threshold value.
In an embodiment of the present invention, if the attenuation across the modular connector is less than a predetermined attenuation threshold, the cross-modular connector does not need to be replaced. That is, the cross-module connector can continue to be used without excessive loss.
If the attenuation degree of the cross-module connecting piece is larger than or equal to the attenuation degree threshold value, the cross-module connecting piece needs to be replaced. That is, excessive wear occurs across the modular connector, requiring replacement of a new one to ensure safe operation of the vehicle.
The following describes a cell voltage correction apparatus provided in an embodiment of the present invention with reference to specific embodiments. Fig. 3 shows a schematic structural diagram of a cell voltage correction apparatus 300 according to an embodiment of the present invention, where the apparatus includes:
the resistance calculation module 310 is configured to calculate a corrected resistance value of the cross-module connecting member in the master-slave module based on the acquired first current of the master-slave module, the first voltage of each battery cell in the master-slave module under the first current, the second current of the master-slave module, and the second voltage of each battery cell in the master-slave module under the second current.
And a compensation differential pressure calculation module 320 for calculating the current compensation differential pressure across the module connecting member according to the corrected resistance value and the collected current of the master module and the slave module.
The correction module 330 is configured to obtain a current sampling voltage of the inter-module battery cell, which is affected by the inter-module connecting member in the master-slave module at the current, and correct the current sampling voltage based on the current compensation differential pressure to obtain a current correction voltage of the inter-module battery cell.
The first current and the second current meet a preset trigger condition, the trigger condition is that a current difference value between the second current and the first current meets a preset threshold value, and the second current is stable in a preset time period.
In the embodiment of the present invention, the trigger condition is set according to a preset correspondence between the cell temperature and the cell current, a charging device parameter of the cell, and a temperature of an environment in which the cell is located.
In an embodiment of the present invention, the resistance calculating module 310 is specifically configured to:
acquiring a first current and a first voltage of each battery cell under the first current;
calculating a first sampling pressure difference based on the first voltage of each battery cell, wherein the first sampling pressure difference is a difference value between the first voltage of the battery cell across the module and an average value of the first voltages of all the battery cells except the battery cell across the module in the master module and the slave module;
determining a second current meeting the trigger condition with the first current, and acquiring a second voltage of each battery cell under the second current;
calculating a second sampling pressure difference according to the second voltage of each battery cell, wherein the second sampling pressure difference is a difference value between the second voltage of the cross-module battery cell and an average value of the second voltages of all the battery cells except the cross-module battery cell in the master module and the slave module;
and obtaining a corrected resistance value of the cross-module connecting piece according to the first current, the second current, the first sampling pressure difference and the second sampling pressure difference.
In an embodiment of the present invention, the resistance calculating module 310 is further specifically configured to:
calculating a current difference between the first current and the second current;
obtaining a voltage difference value between the first sampling pressure difference and the second sampling pressure difference according to the first sampling pressure difference and the second sampling pressure difference;
and calculating the absolute value of the ratio of the voltage difference value to the current difference value, and taking the absolute value as the correction resistance value of the cross-module connecting piece.
In the embodiment of the invention, the first current is the static current of the master module and the slave module or the charging current of the master module and the slave module, and the second current is the charging current of the master module and the slave module.
In an embodiment of the present invention, the modification module 320 is specifically configured to:
and subtracting the difference value of the current compensation differential pressure from the current sampling voltage to obtain the current correction voltage.
In an embodiment of the invention, the first current and the second current are both discharge currents of the master module and the slave module.
In an embodiment of the present invention, the modification module 320 is specifically configured to:
and taking the sum of the current sampling voltage and the current compensation differential pressure as the current correction voltage.
In an embodiment of the present invention, the resistance calculating module 310 is specifically configured to:
acquiring a plurality of pairs of currents of a master module and a slave module, wherein each pair of currents in the plurality of pairs of currents comprises a first current of the master module and a second current of the master module and the slave module which meet triggering conditions;
calculating a plurality of resistance values to be corrected across the module connecting piece based on the acquired first current of each pair of currents, the first voltage of each cell at the first current of each pair of currents, the second current of each pair of currents, and the second voltage of each cell at the second current of each pair of currents;
and determining a correction resistance value of the cross-module connecting piece according to the plurality of resistance values to be corrected.
In an embodiment of the present invention, the cell voltage correction apparatus further includes a fault monitoring apparatus, and the fault monitoring apparatus is configured to:
the temperature across both ends of the module connector is collected.
And determining that the temperatures at the two ends of the cross-module connecting piece are smaller than the temperature threshold values of the master module and the slave module.
In an embodiment of the present invention, the cell voltage correction apparatus further includes an attenuation determination apparatus, where the attenuation determination apparatus is configured to:
calculating the attenuation degree of the cross-module connecting piece based on the corrected resistance value and the preset corresponding relation between the resistance value and the attenuation degree of the cross-module connecting piece;
judging whether the cross-module connecting piece needs to be replaced or not based on the attenuation degree of the cross-module connecting piece and a preset attenuation degree threshold value;
if the attenuation degree of the cross-module connecting piece is smaller than the attenuation degree threshold value, the cross-module connecting piece does not need to be replaced;
if the attenuation degree of the cross-module connecting piece is larger than or equal to the attenuation degree threshold value, the cross-module connecting piece needs to be replaced.
According to the cell voltage correction device provided by the embodiment of the invention, the correction resistance value of the cross-module connecting piece is calculated by using the current of the master module and the slave module which meet the preset trigger condition and the voltage of the cell in the master module and the slave module under the current, and the correction of the voltage acquired by the cross-module cell is realized according to the correction resistance value.
Other details of the cell voltage correction apparatus according to the embodiment of the present invention are similar to those of the cell voltage correction method according to the embodiment of the present invention described above with reference to fig. 2, and are not described again here.
The cell voltage correction method and apparatus according to the embodiment of the present invention described in conjunction with fig. 2 to 3 may be implemented by a cell voltage correction device. Fig. 4 is a schematic diagram illustrating a hardware configuration 400 of the cell voltage correction apparatus according to the embodiment of the present invention.
As shown in fig. 4, the cell voltage correction apparatus 400 in this embodiment includes: a processor 401, a memory 402, a communication interface 403 and a bus 410, wherein the processor 401, the memory 402 and the communication interface 403 are connected by the bus 410 and complete the communication with each other.
In particular, the processor 401 described above may include a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or may be configured as one or more integrated circuits implementing embodiments of the present invention.
Memory 402 may include mass storage for data or instructions. By way of example, and not limitation, memory 402 may include an HDD, floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Memory 402 may include removable or non-removable (or fixed) media, where appropriate. The memory 402 may be internal or external to the cell voltage modification apparatus 400, where appropriate. In a particular embodiment, the memory 402 is a non-volatile solid-state memory. In a particular embodiment, the memory 402 includes Read Only Memory (ROM). Where appropriate, the ROM may be mask-programmed ROM, Programmable ROM (PROM), Erasable PROM (EPROM), Electrically Erasable PROM (EEPROM), electrically rewritable ROM (EAROM), or flash memory or a combination of two or more of these.
The communication interface 403 is mainly used for implementing communication between modules, apparatuses, units and/or devices in the embodiments of the present invention.
The bus 410 includes hardware, software, or both that couple the components of the cell voltage modification apparatus 400 to one another. By way of example, and not limitation, a bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hypertransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an infiniband interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a video electronics standards association local (VLB) bus, or other suitable bus or a combination of two or more of these. Bus 410 may include one or more buses, where appropriate. Although specific buses have been described and shown in the embodiments of the invention, any suitable buses or interconnects are contemplated by the invention.
That is, the cell voltage correction apparatus 400 shown in fig. 4 may be implemented to include: a processor 401, a memory 402, a communication interface 403, and a bus 410. The processor 401, memory 402 and communication interface 403 are coupled by a bus 410 and communicate with each other. The memory 402 is used to store program code; the processor 401 reads the executable program code stored in the memory 402 to execute a program corresponding to the executable program code, so as to implement the method for correcting the cell voltage according to any embodiment of the present invention, thereby implementing the method and apparatus for correcting the cell voltage described in conjunction with fig. 2 to 3.
The embodiment of the invention also provides a computer storage medium, wherein the computer storage medium is stored with computer program instructions; the computer program instructions, when executed by a processor, implement the method for correcting cell voltage provided by the embodiments of the present invention.
It is to be understood that the invention is not limited to the specific arrangements and instrumentality described above and shown in the drawings. A detailed description of known methods is omitted herein for the sake of brevity. In the above embodiments, several specific steps are described and shown as examples. However, the method processes of the present invention are not limited to the specific steps described and illustrated, and those skilled in the art can make various changes, modifications and additions or change the order between the steps after comprehending the spirit of the present invention.
The functional blocks shown in the above-described structural block diagrams may be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, it may be, for example, an electronic circuit, an Application Specific Integrated Circuit (ASIC), suitable firmware, plug-in, function card, or the like. When implemented in software, the elements of the invention are the programs or code segments used to perform the required tasks. The program or code segments may be stored in a machine-readable medium or transmitted by a data signal carried in a carrier wave over a transmission medium or a communication link. A "machine-readable medium" may include any medium that can store or transfer information. Examples of a machine-readable medium include electronic circuits, semiconductor memory devices, ROM, flash memory, Erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, Radio Frequency (RF) links, and so forth. The code segments may be downloaded via computer networks such as the internet, intranet, etc.
It should also be noted that the exemplary embodiments mentioned in this patent describe some methods or systems based on a series of steps or devices. However, the present invention is not limited to the order of the above-described steps, that is, the steps may be performed in the order mentioned in the embodiments, may be performed in an order different from the order in the embodiments, or may be performed simultaneously.
As described above, only the specific embodiments of the present invention are provided, and it can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the system, the module and the unit described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again. It should be understood that the scope of the present invention is not limited thereto, and any equivalent modifications or substitutions can be easily made by those skilled in the art within the technical scope of the present invention.

Claims (10)

1. A cell voltage correction method, characterized in that the method comprises:
acquiring first current of a master module and a slave module and first voltage of each battery cell in the master module and the slave module under the first current;
calculating a first sampling pressure difference based on the first voltage of each cell, wherein the first sampling pressure difference is a difference value between the first voltage of the cross-module cell in the master-slave module and an average value of the first voltages of all cells except the cross-module cell in the master-slave module;
determining a second current meeting a trigger condition with the first current, and acquiring a second voltage of each battery cell under the second current;
calculating a second sampling pressure difference according to the second voltage of each battery cell, wherein the second sampling pressure difference is a difference value between the second voltage of the cross-module battery cell and an average value of the second voltages of all the battery cells except the cross-module battery cell in the master-slave module;
obtaining a correction resistance value of the cross-module connecting piece according to the first current, the second current, the first sampling pressure difference and the second sampling pressure difference;
calculating the current compensation differential pressure of the cross-module connecting piece according to the correction resistance value and the acquired current of the master module and the slave module;
acquiring the current sampling voltage of a cross-module battery cell influenced by the cross-module connecting piece in the master module and the slave module under the current, and correcting the current sampling voltage based on the current compensation pressure difference to obtain the current correction voltage of the cross-module battery cell;
the first current and the second current meet a preset trigger condition, the trigger condition is that a current difference value between the first current and the second current meets a preset threshold value, and the second current is stable within a preset time period;
the obtaining a corrected resistance value of the cross-module connecting piece according to the first current, the second current, the first sampling pressure difference and the second sampling pressure difference comprises:
calculating a current difference between the first current and the second current;
obtaining a voltage difference value between the first sampling pressure difference and the second sampling pressure difference according to the first sampling pressure difference and the second sampling pressure difference;
and calculating the absolute value of the ratio of the voltage difference value to the current difference value, and taking the absolute value as the correction resistance value of the cross-module connecting piece.
2. The method of claim 1, wherein the trigger condition is set according to a preset correspondence between a cell temperature and a cell current, a charging device parameter of the cell, and a temperature of an environment in which the cell is located.
3. The method of claim 1, wherein the first current is a quiescent current of the master module and the slave module or a charging current of the master module and the slave module, and the second current is a charging current of the master module and the slave module.
4. The method of claim 3, wherein the modifying the current sample voltage based on the current compensation voltage difference to obtain a current modified voltage across the module cells comprises:
and subtracting the difference value of the current compensation differential pressure from the current sampling voltage to obtain the current correction voltage.
5. The method of claim 1, wherein the first current and the second current are both discharge currents of the master-slave module.
6. The method of claim 5, wherein the modifying the current sample voltage based on the current compensated voltage differential to obtain a current modified voltage across the module cells comprises:
and taking the sum of the current sampling voltage and the current compensation differential pressure as the current correction voltage.
7. The method of claim 1, further comprising, prior to the calculating a corrected resistance value across module connections in the master and slave modules based on the obtained first current for the master and slave modules, a first voltage per cell in the master and slave modules at the first current, a second current for the master and slave modules, and a second voltage per cell in the master and slave modules at the second current:
collecting temperatures at two ends of the cross-module connecting piece;
and determining that the temperatures at the two ends of the cross-module connecting piece are smaller than the temperature threshold of the master module and the slave module.
8. A cell voltage correction apparatus, characterized in that the apparatus comprises:
a resistance calculation module to: acquiring a first current of a master module and a first voltage of each battery cell in the master module and the slave module under the first current; calculating a first sampling pressure difference based on the first voltage of each cell, wherein the first sampling pressure difference is a difference value between the first voltage of the cross-module cell in the master-slave module and an average value of the first voltages of all cells except the cross-module cell in the master-slave module; determining a second current meeting a trigger condition with the first current, and acquiring a second voltage of each battery cell under the second current; calculating a second sampling pressure difference according to the second voltage of each battery cell, wherein the second sampling pressure difference is a difference value between the second voltage of the cross-module battery cell and an average value of the second voltages of all the battery cells except the cross-module battery cell in the master-slave module; obtaining a correction resistance value of the cross-module connecting piece according to the first current, the second current, the first sampling pressure difference and the second sampling pressure difference;
the compensation pressure difference calculation module is used for calculating the current compensation pressure difference of the cross-module connecting piece according to the corrected resistance value and the acquired current of the master module and the slave module;
the correction module is used for acquiring the current sampling voltage of a cross-module battery cell influenced by the cross-module connecting piece in the master module and the slave module under the current, and correcting the current sampling voltage based on the current compensation differential pressure to obtain the current correction voltage of the cross-module battery cell;
the first current and the second current meet a preset trigger condition, the trigger condition is that a current difference value between the second current and the first current meets a preset threshold value, and the second current is stable in a preset time period;
the resistance calculation module is specifically further configured to:
calculating a current difference between the first current and the second current;
obtaining a voltage difference value between the first sampling pressure difference and the second sampling pressure difference according to the first sampling pressure difference and the second sampling pressure difference;
and calculating the absolute value of the ratio of the voltage difference value to the current difference value, and taking the absolute value as the correction resistance value of the cross-module connecting piece.
9. A cell voltage correction apparatus, characterized in that the apparatus comprises:
a memory for storing a program;
a processor configured to execute the program stored in the memory to perform the cell voltage correction method according to any one of claims 1 to 8.
10. A computer-readable storage medium having stored thereon computer program instructions, which, when executed by a processor, implement the cell voltage correction method according to any one of claims 1 to 7.
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