CN110048487B - Control method and system for battery charging and discharging - Google Patents
Control method and system for battery charging and discharging Download PDFInfo
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- CN110048487B CN110048487B CN201910407036.4A CN201910407036A CN110048487B CN 110048487 B CN110048487 B CN 110048487B CN 201910407036 A CN201910407036 A CN 201910407036A CN 110048487 B CN110048487 B CN 110048487B
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- 238000007599 discharging Methods 0.000 title claims abstract description 77
- 238000000034 method Methods 0.000 title claims abstract description 62
- 238000006243 chemical reaction Methods 0.000 claims description 14
- 238000001514 detection method Methods 0.000 claims description 11
- 238000012163 sequencing technique Methods 0.000 claims description 11
- 210000004027 cell Anatomy 0.000 description 93
- 230000000875 corresponding effect Effects 0.000 description 19
- 238000005215 recombination Methods 0.000 description 7
- 230000006798 recombination Effects 0.000 description 7
- 238000004364 calculation method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000004146 energy storage Methods 0.000 description 4
- 210000004460 N cell Anatomy 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000007792 addition Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
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- 230000002596 correlated effect Effects 0.000 description 1
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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
- H01M10/44—Methods for charging or discharging
- H01M10/441—Methods for charging or discharging for several batteries or cells simultaneously or sequentially
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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
- H02J7/0019—Circuits for equalisation of charge between batteries using switched or multiplexed charge circuits
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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
- H02J7/0063—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with circuits adapted for supplying loads from the battery
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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Abstract
The application discloses a battery charging and discharging control method and a system thereof, wherein the battery charging and discharging control method specifically comprises the following steps: detecting a state of each battery cell; selecting a plurality of appointed battery units to combine into a series circuit for charging/discharging according to the states of all the battery units; after a period of time, the battery cells are recombined according to the current states of all the battery cells to obtain a new series circuit, and the battery cells in the new series circuit are charged/discharged. This application can carry out charge-discharge dynamic balance control to the group battery, on the basis of guaranteeing the stable input/output of series battery group, realizes being full of group battery and puts, and the redundant configuration has been avoided to all capacity ability of make full use of group battery.
Description
Technical Field
The application relates to the field of batteries, in particular to a battery charging and discharging control method and a system thereof.
Background
In the prior art, due to the problems of production process and the like, the capacity of a single battery is small, and the requirement of a load on energy storage capacity is difficult to meet, so that the batteries are inevitably used in a group. In order to meet the required current, voltage or power requirements, a large number of single batteries are required to be connected in series and in parallel to form a large-scale battery system. In the battery grouping technology, the small-capacity single battery grouping or net formation has great advantages in the aspects of safety, reliability and management and control performance of the energy storage system compared with the large-capacity single battery. This has been demonstrated in a number of practical applications, for example, a tesla Model S electric vehicle employs 8127 cells 18650 small capacity cells. However, the battery cells have inevitable inconsistency, and even the batteries of the same manufacturer and the same batch have common differences in parameters such as charge and discharge characteristics, temperature characteristics, capacity, internal resistance, and the like, and the differences continue to increase during the use of the batteries. In order to solve the problem caused by the inconsistency of the single batteries, ensure good performance of the batteries and prolong the service life of the batteries, the batteries need to be managed and controlled reasonably and effectively except for capacity grading and screening of the single batteries.
The conventional battery management system mainly adopts equalization technology, including active equalization and passive equalization. The passive equalization discharges the batteries with high voltage by adding a bypass resistor to each battery and the like, so that the voltages of the batteries in the series battery pack are balanced, the equalization problem in the charging process is mainly solved, the discharge equalization cannot be helped, meanwhile, an equalization circuit can cause certain energy loss, and the energy use efficiency of a battery system is reduced; active balancing realizes energy transfer between adjacent batteries by adding energy storage or conversion devices such as capacitors and transformers, and has low balancing loss, but has the disadvantages of multiple components, complex structure, high cost, low balancing efficiency and difficulty in fully utilizing all capacities of the battery pack. Therefore, a suitable control method for charging and discharging the battery is needed, so that a new battery grouping mode can be generated again, and the battery in the large-scale energy storage system after the battery is grouped is charged and discharged efficiently based on the mode.
Disclosure of Invention
The application aims to provide a battery charging and discharging control method and a battery charging and discharging control system, which can realize dynamic balance of a battery pack in the charging and discharging processes, solve the problem of battery consistency and improve the capacity utilization rate of the battery pack.
In order to achieve the above object, the present application provides a method for controlling charging and discharging of a battery, which specifically includes the following steps: detecting a state of each battery cell; selecting a plurality of appointed battery units to combine into a series circuit for charging/discharging according to the states of all the battery units; and according to the current states of all the battery units, continuously recombining to obtain a new series circuit, and charging/discharging the battery units in the new series circuit.
As above, at any time during the charging and discharging process, the terminal voltage, the current, the internal resistance, and the state of charge information data of each battery cell are obtained through detection and calculation, and the current state of the battery cell is determined according to the state of charge data.
As above, wherein, during the charge and discharge, when the charge/discharge time reaches a designated value, the battery cells are recombined to form a new series circuit according to the current state of the battery cells.
As described above, the charging and discharging of the battery cell specifically includes the following substeps: according to the current state of the battery units, a plurality of appointed battery units are selected from the N battery units, the battery units are connected into the circuit to form a series battery pack, and the battery units in the series battery pack are charged/discharged.
As above, the step of forming the battery cell access circuit into the series battery pack specifically includes the following steps: sequencing all the battery units; according to the sequencing result, selecting a plurality of appointed battery units, and summing the terminal voltage values of the battery units to ensure that the summing result does not exceed the appointed range of the direct current bus voltage; and according to the selection result, connecting a plurality of specified battery units into the circuit to form a series battery pack.
In the charging process, the n battery units with low state of charge values are selected according to the sequencing result, so that the sum of the terminal voltages of the n battery units does not exceed the specified range of the direct-current bus voltage.
As above, during the discharging process, the n 'battery cells with high state of charge values are selected according to the sorting result, so that the sum of the terminal voltages of the n' battery cells does not exceed the specified range of the dc bus voltage.
A control system for charging and discharging a battery specifically comprises a battery pack, a detection unit, a control unit, an energy conversion unit and a load; the battery pack comprises battery units, a series switch Ss (i) and a parallel switch Sp (i), wherein the series switch Ss (i) and the parallel switch Sp (i) are connected with the battery units, and the terminal voltages of the battery units are used for meeting the voltage requirements of a load or a system; the detection unit is used for detecting and calculating terminal voltage, current, internal resistance and charge state information data of each battery unit in the battery pack; the control unit controls the combination mode of the batteries in the battery pack according to the current state of the battery unit and the load requirement provided by the energy conversion unit; the energy conversion unit also converts the direct current output by the combined battery pack to match the voltage requirement of the load.
As described above, one end of series switch ss (i) is connected to one positive end of battery cell b (i), the other end of series switch ss (i) is connected to one end of parallel switch sp (i), and the other end of parallel switch sp (i) is connected to one negative end of battery cell b (i).
As above, the series switch ss (i) corresponding to the battery cell to be charged or discharged is closed, and the parallel switch sp (i) is opened; otherwise, the corresponding series switch ss (i) is opened, and the parallel switch sp (i) is closed.
The application has the following beneficial effects:
(1) the control method and the system for battery charging and discharging can perform segmented control in the charging and discharging processes, dynamically adjust the combination of the battery units connected into the series circuit based on the current state of the battery units in each fixed time, dynamically select the combination of the battery units with the lowest charge state in the charging process, and dynamically select the combination with the highest charge state in the discharging process.
(2) The battery charging and discharging control method and the battery charging and discharging control system can perform charging and discharging dynamic balance control on the battery pack, full charging and discharging of the battery pack are achieved on the basis of ensuring stable input/output of the series battery pack, all capacity capabilities of the battery pack are fully utilized, and redundant configuration is avoided.
(3) The battery charging and discharging control method and the battery charging and discharging control system can provide a new battery grouping mode, and balance control of battery charging and discharging is achieved based on the mode.
(4) According to the battery charging and discharging control method and the battery charging and discharging control system, each battery unit is connected with the series switch and the parallel switch, and the battery units can be connected into or disconnected from the series circuit at any time through combined control of the two switches.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art according to the drawings.
FIG. 1 is a schematic diagram of an internal structure of a control system for charging and discharging a battery according to an embodiment of the present application;
fig. 2 is a circuit diagram of internal connections of a battery pack provided according to an embodiment of the present application;
fig. 3 is a flowchart of a control method for charging and discharging a battery according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application are clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The application relates to a control method and a system for battery charging and discharging. According to the method and the device, dynamic balance of the battery pack in the charging and discharging processes can be achieved, the problem of battery consistency is solved, and the capacity utilization rate of the battery pack is improved.
As shown in fig. 1, a schematic diagram of an internal structure of a battery charging and discharging control system provided by the present application specifically includes a battery pack 101, a detection unit 102, a control unit 103, an energy conversion unit 104, and a load 105.
Wherein the battery pack 101 is used to provide a corresponding voltage to the load 105 by charging or discharging. As shown in fig. 2, a connection circuit diagram of battery cells in a battery pack is shown.
Specifically, the battery pack 101 includes N battery cells b (i), a plurality of series switches ss (i), and a plurality of parallel switches sp (i). Wherein the battery unit b (i) includes one or more single batteries (not shown in the figure).
The number of series switches ss (i) and parallel switches sp (i) is equal to the number of battery cells.
Preferably, the single batteries are integrated in the battery units b (i) through a direct parallel connection or a parallel connection and then a series connection.
Further, one end of series switch ss (i) is connected to one positive end of battery cell b (i), the other end of series switch ss (i) is connected to one end of parallel switch sp (i), and the other end of parallel switch sp (i) is connected to one negative end of battery cell b (i). The series switch ss (i) is connected in series with the battery cell b (i), and the parallel switch sp (i) is connected in parallel with the series switch ss (i) and the battery cell b (i) through the above connection.
The detection unit 102 is connected to the battery pack 101, and is configured to detect and calculate information data such as terminal voltage, current, internal resistance, and SOC (state of charge) of each battery cell in the battery pack 101, and determine a current state of the battery cell in the battery pack according to the SOC data.
Specifically, the SOC data may be calculated according to parameters such as the detected terminal voltage, current, internal resistance, and the like, and the calculation method may refer to a calculation method of the SOC in the prior art.
The control unit 103 is connected to the detection unit 102, the battery pack 101, and the energy conversion unit 104, respectively, where the energy conversion unit 104 can obtain a voltage requirement of a load, and the control unit 103 is configured to control the battery combination mode in the battery pack to charge/discharge the battery units according to a result obtained by sorting the current states of the battery units and the load requirement provided by the energy conversion unit 105, so as to control the series switch and the parallel switch to be turned on or off.
Wherein, in the charging process: the control unit 103 selects n battery units with low SOC values according to the sorting result, so that the sum of the terminal voltages of the n battery units does not exceed the specified range of the DC bus voltage, and the n battery units are charged; in the discharging process: the control unit 103 selects n ' battery cells with high SOC values according to the sorting result, so that the sum of the terminal voltages of the n ' battery cells does not exceed the specified range of the dc bus voltage, and discharges the n ' battery cells.
Specifically, according to whether the formula is satisfied or not
And selecting the battery unit for charging. Where U' (i) is the terminal voltage of the ith cell, U is the dc bus voltage of the system, n is the number of cells to be summed, and i is 1, 2, …, n. And if the sum of the terminal voltages of the n battery units is equal to the direct current bus voltage of the system, charging the n battery units.
For another example, if
If the calculation result of (1) does not exceed the specified range of U, the n battery units are still charged.
In particular, also according to the formula
And selecting the battery unit for discharging. Where n 'is the number of cells to be summed, i is 1, 2, …, n'. . If the sum of the terminal voltages of the n 'battery cells is equal to the direct-current voltage, the n' battery cells are discharged.
For another example, if
If the calculation result of (c) does not exceed the specified range of U, the n' battery cells are still discharged.
Preferably, the specified range is set by a person and can be modified, and thus is not limited.
The energy conversion unit 104 is connected to the battery pack 101 and the load 105, and the energy conversion unit 104 performs energy transfer with the load and the battery pack, and is configured to convert the dc power output by the combined battery pack to match the voltage requirement of the load.
Fig. 3 is a flowchart illustrating a method for controlling charging and discharging of a battery according to the present application.
Step S310: the state of each battery cell is detected.
Specifically, the detection unit 102 detects the state of each battery cell in the battery pack 101 at any time, among others. The state is determined by information data such as the SOC value detected by the detection unit 102.
Step S320: according to the states of all the battery units, a plurality of appointed battery units are selected to be combined into a series circuit for charging/discharging.
Specifically, the control unit 103 performs selection of a battery cell and charging/discharging thereof according to the battery state detected by the detection unit 102. And according to the states of the battery units, selecting N battery units from the N battery units, and connecting the N battery units to the circuit to form a series battery pack.
In the charging process, the following substeps are specifically included:
step D1: and according to the states of the battery units, selecting N battery units from the N battery units, and connecting the N battery units to the circuit to form a series battery pack.
The method for forming the series battery pack by selecting the n battery units and connecting the n battery units to the access circuit comprises the following steps:
step W1: the battery cells are sorted.
Specifically, the battery units are sorted according to the SOC value of the battery units. The magnitude of the SOC value is positively correlated with the voltage of the battery cell, and therefore, the larger the SOC value is, the larger the terminal voltage of the battery cell is, and the smaller the SOC value is.
Step W2: and according to the sequencing result, selecting a plurality of designated battery units with lower SOC values for summation.
Specifically, according to whether the formula is satisfied or not
And determining the selected battery unit. Where U' (i) is the terminal voltage of the ith cell, U is the dc bus voltage of the system, n is the number of cells to be summed, and i is 1, 2, …, n.
Illustratively, if the number of battery cells in the battery pack is 10, the dc bus voltage of the system is 100V, the terminal voltages of the battery cells will be added in order from low to high, if the sum of the terminal voltages added up from the last battery cell to the 2 nd battery cell is equal to 100V, n is 9, and if the sum of the terminal voltages of the last to 4 th battery cells is equal to 100V, n is 7.
It is noted that since there may be real-time, subtle errors and losses in the terminal voltages of the cells, the sum of the terminal voltages of the cells is approximately equal to the dc bus voltage, also referred to herein as equal.
In another case, if the terminal voltage of the battery cell does not exceed the specified range of the dc bus voltage, the value of n can still be determined. For example, if the sum of the terminal voltages of n battery cells is 110V, the terminal voltage of the battery cell does not exceed the specified range of the dc bus voltage, and the value of n can be determined.
Preferably, the designated range is set according to the specific situation of the system, and the specific numerical value is not limited herein.
Step W3: and connecting the n battery units into the circuit to form a series battery pack according to the selection result.
The sum of the terminal voltages of the n battery cells is made not to exceed the specified range of the dc bus voltage by step W2, thereby determining the number and positions of the battery cells connected in the series circuit.
Specifically, forming the series battery pack may be implemented by turning off series switches corresponding to the n battery cells and turning off parallel switches corresponding to the n battery cells.
Illustratively, if the states of B (1), B (3), B (5) and B (7) are poor, the battery packs are connected into the circuit preferentially to form a series battery pack, specifically, a series switch Ss (1) corresponding to B (1) is closed, and a parallel switch Sp (1) is opened; the series switch Ss (3) corresponding to the B (3) is closed, and the parallel switch Sp (3) is opened; the series switch Ss (5) corresponding to the B (5) is closed, and the parallel switch Sp (5) is opened; and the series switch Ss (7) corresponding to the B (7) is closed, and the parallel switch Sp (7) is opened. And (4) the corresponding series switches Ss (i) of the rest N-N battery units which do not need to be connected into the circuit are opened, the parallel switches Sp (i) are closed, and the N-N battery units temporarily exit the series battery pack.
It should be noted that B (1), B (3), B (5), and B (7) are only examples, and the type or number of the battery cells in actual cases is not limited herein.
Preferably, the number of the remaining N-N battery cells that do not require access to the circuit should be much larger than 1.
Step D2: in response to the completion of the series connection of the battery packs, the battery packs are charged.
Specifically, the corresponding battery cell is charged according to the connected battery pack.
Specifically, the following sub-steps are specifically included in the discharging process:
step P1: according to the states of the battery units, N' battery units are selected from the N battery units and connected into a circuit to form a series battery pack.
The method for forming the series battery pack by selecting the n 'battery units and connecting the n' battery units to the circuit comprises the following steps:
step Q1: the battery cells are sorted.
Preferably, similar to the sorting method in step W1, the battery cells are sorted from high to low according to their SOC values, and the larger the SOC value, the earlier the battery cells are sorted.
Step Q2: and according to the sequencing result, selecting a plurality of specified battery units with higher SOC values for summation.
Specifically, several battery units with higher SOC values are selected, for example, the terminal voltages of the first 5 battery units are selected from 10 battery units for summation.
The values of a plurality of battery units can be obtained through the formula
Specifically, n 'is the number of cells to be summed, and i is 1, 2, …, n'. In step Q2, if the terminal voltages of the first 5 battery cells satisfy the rated dc voltage, n 'is 5, and if the terminal voltages of the first 3 battery cells are equal to the dc bus voltage, n' is 3.
Further, if the terminal voltage of the battery unit does not exceed the specified range of the rated direct current voltage, the value of n' can still be determined.
Step Q3: and according to the selection result, connecting the n' battery units into the circuit to form a series battery pack.
The number and location of the battery cells connected into the series circuit are determined by the sum of the terminal voltages of the n' battery cells not exceeding the specified range of the dc bus voltage, via step Q2.
Specifically, forming the series battery pack may be implemented by opening series switches corresponding to n' battery cells and closing parallel switches corresponding to n battery cells.
For example, if the states of B (2), B (4), B (6), and B (8) are good, the series switch Ss (2) corresponding to B (2) is closed, and the parallel switch Sp (2) is opened; the series switch Ss (4) corresponding to the B (4) is closed, and the parallel switch Sp (4) is opened; the series switch Ss (6) corresponding to the B (6) is closed, and the parallel switch Sp (6) is opened; and the series switch Ss (8) corresponding to the B (8) is closed, and the parallel switch Sp (8) is opened. The remaining N-N' battery cells that do not require access circuitry are temporarily removed from access to the series battery pack.
Preferably, the number of the remaining N-N' battery cells that do not require access to the circuit should be much larger than 1.
Step P2: in response to the completion of the series connection of the battery packs, the battery packs are discharged.
Specifically, the corresponding battery cell is discharged according to the connected battery pack.
Step S330: it is determined whether the charge/discharge has reached a specified time or whether the difference between the maximum and minimum state of charge values in all of the battery cells exceeds a specified threshold.
If the difference between the maximum and minimum state of charge values in all the battery units exceeds the specified threshold value, step S320 is executed again, the states of the battery units are determined, and the battery units are continuously recombined into a series circuit for charging/discharging according to the states.
And if the specified time is not reached or the difference value of the maximum SOC value and the minimum SOC value in all the current battery units does not exceed the specified threshold value, continuing charging/discharging.
Wherein the recombination of the battery cells can be performed after a designated interval during the charge/discharge process. The value of the designated interval is set by human and can be modified, and the specific value is not limited in the present embodiment.
Specifically, during the charging process, if N battery cells with lower states of charge are being charged, after a specified time interval is reached, the N battery cells are subjected to state judgment together with the remaining N-N battery cells, and are recombined, i.e., steps W1-W3 are performed.
For example, if the total number of the battery units is 20, the battery units with the lower states of charge are selected to form a series battery pack to be charged, after a specified time interval is reached, the states of the 8 battery units and the remaining 12 battery units are judged again, the battery units are recombined to obtain a new series battery pack, and then the charging is continued.
According to the above charging method, overcharge or skip charge of the battery cell can be prevented.
The recombination of the battery units can be carried out according to the difference value of the maximum SOC and the minimum SOC in all the current battery units as a recombination triggering condition.
Specifically, when the difference between the SOC of a certain cell and the SOC of a certain cell in the N cells exceeds the predetermined threshold while the N cells are charged, steps W1-W3 are executed again to select a new cell to be charged.
Specifically, the principle of the recombination of the battery cells during the discharge process is similar to that of the recombination of the battery cells during the charge process. Specifically, in the discharging process, if N ' battery cells with higher states of charge are being discharged, after a specified time interval is reached, the N ' battery cells are subjected to state judgment together with the remaining N-N ' battery cells, and are recombined, i.e., steps Q1-Q3 are performed.
Furthermore, the recombination of the battery units can be carried out according to the difference value of the maximum SOC and the minimum SOC in all the current battery units as a recombination triggering condition.
Specifically, when the difference between the SOC value of a certain cell and the SOC of a certain cell exceeds a predetermined threshold value among the N cells during the discharge of the N' cells, steps Q1 to Q3 are executed again to select a new cell to be discharged.
Specifically, the corresponding series switches ss (i)/sp (i) may be turned off/disconnected according to the reselected battery cell to form a series battery pack, and the reselected battery cell may be charged/discharged. The reference step and the specific connection manner of the charging/discharging method can refer to the description in step S320, which is not described herein again.
By continuously recombining the battery packs, it can be achieved that all the battery cells can be fully charged during the charging process; during the discharge process, all the battery units can be emptied as much as possible. In the control method for charging and discharging, no extra battery energy loss exists, full charging and discharging of the battery pack can be realized, and the arrangement utilization efficiency and the energy conversion efficiency of the battery pack are improved.
Step S340: in response to all battery cells being fully charged or empty, the charging or discharging process ends.
Wherein all the battery units are charged and discharged by continuously carrying out new combination until the charging/discharging task is completed.
The application has the following beneficial effects:
(1) the control method and the system for charging and discharging the battery can perform segmented control in the charging and discharging processes, dynamically adjust the combination of the battery units connected into the series circuit based on the current state of the battery units in each time, dynamically select the combination of the battery units with the lowest charge state in the charging process, and dynamically select the combination with the highest charge state in the discharging process.
(2) The battery charging and discharging control method and the battery charging and discharging control system can perform charging and discharging dynamic balance control on the battery pack, full charging and discharging of the battery pack are achieved on the basis of ensuring stable input/output of the series battery pack, all capacity capabilities of the battery pack are fully utilized, and redundant configuration is avoided.
(3) The battery charging and discharging control method and the battery charging and discharging control system can provide a new battery grouping mode, and balance control of battery charging and discharging is achieved based on the mode.
(4) According to the battery charging and discharging control method and the battery charging and discharging control system, each battery unit is connected with the series switch and the parallel switch, and the battery units can be connected into or disconnected from the series circuit at any time through combined control of the two switches.
Although the present application has been described with reference to examples, which are intended to be illustrative only and not to be limiting of the application, changes, additions and/or deletions may be made to the embodiments without departing from the scope of the application.
The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (10)
1. A method for controlling charging and discharging of a battery is characterized by comprising the following steps:
detecting a state of each battery cell;
selecting a plurality of appointed battery units to combine into a series circuit for charging/discharging according to the states of all the battery units;
according to the current states of all the battery units, continuously recombining to obtain a new series circuit, and charging/discharging the battery units in the new series circuit;
when the battery units are discharged, if the difference between the SOC value of a certain battery unit and the SOC of the certain battery unit exceeds a specified threshold, the following steps are executed again to select a new discharged battery unit, and the steps specifically include:
sequencing all the battery units;
according to the sequencing result, selecting a plurality of specified battery units with higher SOC values for summation;
according to the selection result, connecting a plurality of appointed battery units into a circuit to form a series battery pack;
in the discharging process, if N ' battery units with higher charge states are discharging, after a specified time interval is reached, the N ' battery units and the rest N-N ' battery units are subjected to state judgment together to be recombined into a new series battery pack.
2. The method of claim 1, wherein the terminal voltage, current, internal resistance, and state of charge information data of each cell are detected and calculated at any time during the charging and discharging process, and the current state of the cell is determined according to the state of charge data.
3. The method of controlling charge and discharge of a battery according to claim 2, wherein the battery cells are recombined to form a new series circuit according to the current states of the battery cells when the charge/discharge time reaches a designated value during the charge and discharge.
4. The method for controlling charging and discharging of a battery according to claim 3, wherein the charging and discharging of the battery cell specifically includes the substeps of:
according to the current state of the battery units, a plurality of appointed battery units are selected from the N battery units, the battery units are connected into the circuit to form a series battery pack, and the battery units in the series battery pack are charged/discharged.
5. The method for controlling the charging and discharging of the battery according to claim 4, wherein the step of connecting the battery cells to the circuit to form a series battery pack specifically comprises the steps of:
sequencing all the battery units;
according to the sequencing result, selecting a plurality of appointed battery units, and summing the terminal voltage values of the battery units to ensure that the summing result does not exceed the appointed range of the direct current bus voltage;
and according to the selection result, connecting a plurality of specified battery units into the circuit to form a series battery pack.
6. The method of claim 5, wherein during the charging process, the n battery cells with low state of charge values are selected according to the sorting result, so that the sum of the terminal voltages of the n battery cells does not exceed the specified range of the DC bus voltage.
7. The battery charging and discharging control method according to claim 5, wherein during the discharging process, the n 'battery cells with high state of charge values are selected according to the sorting result, so that the sum of the terminal voltages of the n' battery cells does not exceed the specified range of the dc bus voltage.
8. A control system for charging and discharging a battery is characterized by specifically comprising a battery pack, a detection unit, a control unit, an energy conversion unit and a load;
the battery pack comprises battery units, and a series switch Ss (i) and a parallel switch Sp (i) which are connected with the battery units, wherein the terminal voltages of the battery units are used for meeting the requirement voltage of a load or a system;
the detection unit is used for detecting and calculating terminal voltage, current, internal resistance and charge state information data of each battery unit in the battery pack;
the control unit controls the combination mode of the batteries in the battery pack according to the current state of the battery unit and the load requirement provided by the energy conversion unit;
the energy conversion unit is used for converting the direct current output by the combined battery pack so as to match the voltage requirement of the load;
when the control unit controls the battery combination mode to discharge the battery units, and the difference value between the SOC value of a certain battery unit and the SOC of the certain battery unit exceeds a specified threshold value, the following steps are executed again to select a new discharged battery unit, and the steps specifically include:
sequencing all the battery units;
according to the sequencing result, selecting a plurality of specified battery units with higher SOC values for summation;
according to the selection result, connecting a plurality of appointed battery units into a circuit to form a series battery pack;
in the discharging process, if N ' battery units with higher charge states are discharging, after a specified time interval is reached, the N ' battery units and the rest N-N ' battery units are subjected to state judgment together to be recombined into a new series battery pack.
9. The battery charging and discharging control system according to claim 8, wherein one end of the series switch ss (i) is connected to one end of the positive pole of the battery cell b (i), the other end of the series switch ss (i) is connected to one end of the parallel switch sp (i), and the other end of the parallel switch sp (i) is connected to one end of the negative pole of the battery cell b (i).
10. The battery charging and discharging control system according to claim 8, wherein the series switch ss (i) corresponding to the battery cell to be charged or discharged is closed, and the parallel switch sp (i) is opened; otherwise, the corresponding series switch ss (i) is opened, and the parallel switch sp (i) is closed.
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| CN110797590B (en) * | 2019-09-16 | 2022-08-23 | 安徽绿沃循环能源科技有限公司 | Energy storage power station efficiency improving method and system based on secondary utilization of battery pack |
| CN110970969B (en) * | 2019-11-01 | 2021-10-15 | 武汉船用电力推进装置研究所（中国船舶重工集团公司第七一二研究所） | Alternate rest balance topology and control method of lithium ion power battery for electric ship |
| CN110899151B (en) * | 2019-11-29 | 2021-04-27 | 南京涛博能源科技有限公司 | Device and method for rapidly screening charging and discharging characteristics of lithium battery |
| CN111276765A (en) * | 2020-03-12 | 2020-06-12 | 姜家刚 | Battery core capacity grading device and equipment |
| CN112600265B (en) * | 2020-12-02 | 2021-11-30 | 刘铭新 | Battery pack charging/discharging method and device suitable for low-temperature environment |
| CN112737015B (en) * | 2020-12-22 | 2023-05-16 | 西安科技大学 | Lithium battery balance control system and control method based on SOC |
| CN113517745A (en) * | 2021-08-18 | 2021-10-19 | 四川中青轩宇科技有限公司 | Intermittent charging system and method |
| CN113629821B (en) * | 2021-09-02 | 2024-04-12 | 阳光电源股份有限公司 | Energy storage system and control method thereof |
| CN113629822A (en) * | 2021-09-02 | 2021-11-09 | 阳光电源股份有限公司 | Energy storage system and control method thereof |
| CN114726033A (en) * | 2022-03-28 | 2022-07-08 | 清华大学 | Battery system charging and discharging control method based on dynamic reconfigurable battery network |
| WO2023240454A1 (en) * | 2022-06-14 | 2023-12-21 | 宁德时代新能源科技股份有限公司 | Control method and control apparatus of energy storage system, and energy storage system |
| CN116345618B (en) * | 2023-03-08 | 2024-02-20 | 湖南旭联科技有限公司 | Recombination discharging method and system for multiple mobile energy storage batteries |
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| CN105531866B (en) * | 2013-04-30 | 2018-03-20 | 英属盖曼群岛商立凯绿能移动科技股份有限公司 | Large Electric car power supply structure and its battery case have holidays by turns sequence control method |
| CN104734236B (en) * | 2013-12-19 | 2018-01-19 | 北汽福田汽车股份有限公司 | Battery set charge/discharge device and method |
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