CN118473065B - Layered active equalization circuit and method for retired power battery pack - Google Patents
Layered active equalization circuit and method for retired power battery pack Download PDFInfo
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- CN118473065B CN118473065B CN202410938038.7A CN202410938038A CN118473065B CN 118473065 B CN118473065 B CN 118473065B CN 202410938038 A CN202410938038 A CN 202410938038A CN 118473065 B CN118473065 B CN 118473065B
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- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000004804 winding Methods 0.000 claims abstract description 43
- 230000002457 bidirectional effect Effects 0.000 claims abstract description 40
- 238000010521 absorption reaction Methods 0.000 claims abstract description 15
- 239000011159 matrix material Substances 0.000 claims abstract description 9
- 238000004146 energy storage Methods 0.000 claims description 97
- 238000007599 discharging Methods 0.000 claims description 34
- 238000007600 charging Methods 0.000 claims description 33
- 230000007423 decrease Effects 0.000 claims description 23
- 239000003990 capacitor Substances 0.000 claims description 16
- 230000005284 excitation Effects 0.000 claims description 11
- 238000012546 transfer Methods 0.000 claims description 11
- 230000001066 destructive effect Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 10
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 241000022852 Letis Species 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
- H02J7/0014—Circuits for equalisation of charge between batteries
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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
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/44—Methods for charging or discharging
- H01M10/441—Methods for charging or discharging for several batteries or cells simultaneously or sequentially
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
- H02J7/0048—Detection of remaining charge capacity or state of charge [SOC]
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0038—Circuits or arrangements for suppressing, e.g. by masking incorrect turn-on or turn-off signals, e.g. due to current spikes in current mode control
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0048—Circuits or arrangements for reducing losses
- H02M1/0054—Transistor switching losses
- H02M1/0058—Transistor switching losses by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
- H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
- H02M3/33584—Bidirectional converters
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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
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
- H01M2010/4271—Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
-
- 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
- H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J2207/20—Charging or discharging characterised by the power electronics converter
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
The invention discloses a layered active equalization circuit of a retired power battery pack, which comprises a retired power battery, wherein the retired power battery pack comprisesBattery packBattery packPositive and primary side switching tubeIs connected with one end of the primary side switch tubeThe other end of the primary winding of the bidirectional flyback transformer is connected with a battery group through leakage inductancenegative pole connection; battery teamCompleting the balance in the battery pairs and the balance among the battery pairs, and jointly completing the top-layer balance by the retired power battery pack, the switch matrix and the bidirectional flyback transformer; the two-layer equalization circuit structure shortens the equalization path and reduces the equalization time; the LCD lossless absorption network is also added to absorb voltage spikes caused by leakage inductance; the invention also discloses a layered active equalization method of the retired power battery pack, which comprises the steps of firstly performing battery pair internal equalization; and then carrying out battery pair-to-pair equalization and finally carrying out group-to-group equalization.
Description
Technical Field
The invention belongs to the technical field of battery pack equalization, in particular relates to a layered active equalization circuit of a retired power battery pack, and also relates to a layered active equalization method of the retired power battery pack, which is suitable for equalizing the SOC value of a battery in the retired power battery pack.
Background
With the increase of energy shortage and environmental pollution problems in recent years, the new energy automobile industry is rapidly developing, and a large number of lithium ion power batteries are applied to new energy automobiles as main energy sources. With the increase of the service life of new energy automobiles, a large number of lithium ion power batteries are retired from the new energy automobiles. Generally, the rated capacity of the retired battery is still 70% -80% of the initial rated capacity, and after sorting and recombination, part of retired power battery can still be used in echelon products in the fields of base station preparation, energy storage, charging and electricity changing and the like. The secondary use performance and service life of the retired battery can be affected due to obvious inconsistency of the retired battery. Therefore, the echelon utilization technology of the retired power battery becomes a research hot spot at home and abroad, and the retired battery is balanced in the echelon utilization process, so that the method has important significance in the aspects of preventing the battery from being overcharged and overdischarged, ensuring the available capacity of the battery pack, ensuring the safe operation and the like.
Common battery equalization includes passive equalization and active equalization, where passive equalization is energy-consuming equalization, typically converting excess electrical energy into thermal energy for consumption, but continuously losing energy in the form of thermal energy affects the battery's life. Active equalization is of the non-energy consuming type and generally comprises of the lc-based type, the transformer-based type, the DC-DC converter-based type, etc. Compared with passive equalization, active equalization has a relatively complex structure, but has high equalization speed and high energy utilization rate, and is more suitable for the equalization technology of retired power batteries. In the prior art, the single-inductance type equalizing circuit has the problems of low equalizing speed, difficult design and high cost when a single transformer is applied to a long-string retired power battery pack, and the problem of voltage peak caused by leakage inductance exists in a bidirectional flyback transformer.
Disclosure of Invention
The invention aims to solve the problems in the prior art, and provides a layered active equalization circuit of a retired power battery pack and a layered active equalization method of the retired power battery pack.
The above object of the present invention is achieved by the following technical means:
A layered active equalization circuit of a retired power battery pack comprises retired power batteries, a switch matrix and a bidirectional flyback transformer; the retired power battery pack comprises Battery packI epsilon { 1-n }, battery groupThe positive electrode of (a) is connected with the primary side switch tube through a switch K 2i-1 Is connected with one end of the primary side switch tubeIs arranged at the other end of the pipe and is leakage inductanceIs connected with one end of the leakage inductanceThe other end of the primary winding of the bidirectional flyback transformer is connected with one end of the primary winding of the bidirectional flyback transformer, and the other end of the primary winding of the bidirectional flyback transformer is connected with the battery group through a switch K 2i Is connected with the negative electrode of the battery;
battery pack Positive electrode of (c) and battery packIs connected with the negative electrode of the battery groupNegative electrode of (c) and battery packPositive electrode connection of battery small groupThe positive pole of (a) is connected with the power bus V BUS, and the battery groupIs grounded (connected to GND); the bidirectional flyback transformer adopts a heteropolarity wiring mode.
Battery packs as described aboveComprising a battery unitBattery unitEnergy storage inductance L 3i, degaussing resistor R 3i, switching tube Q 6i-1 and switching tube Q 6i, one end of energy storage inductance L 3i connected in parallel with degaussing resistor R 3i and battery unitIs provided, and battery cellThe other end of the energy storage inductance L 3i connected in parallel with the degaussing resistor R 3i is connected with one end of the switching tube Q 6i-1 and one end of the switching tube Q 6i, and the battery unitThe positive electrode of (a) is connected with the other end of the switch tube Q 6i-1, and the battery unitNegative electrode of (2) and switch tube Q the other end of 6i is connected; battery cellPositive electrode of (a) as a battery packPositive electrode of (a), battery cellIs used as a battery groupIs a negative electrode of (a).
Battery cell as described aboveComprising single batterySingle batteryEnergy storage inductance L 3i-2, degaussing resistor R 3i-2, switching tube Q 6i-5 and switching tube Q 6i-4, one end of energy storage inductance L 3i-2 connected in parallel with degaussing resistor R 3i-2 and single batteryIs provided with a negative electrode and a single batteryThe other end of the energy storage inductance L 3i-2 connected in parallel with the degaussing resistor R 3i-2 is connected with one end of the switch tube Q 6i-5 and one end of the switch tube Q 6i-4, and the single batteryThe positive electrode of (a) is connected with the other end of the switch tube Q 6i-5, and a single batteryNegative electrode of (2) and switch tube Q the other end of 6i-4 is connected; single batteryIs used as a battery unitPositive electrode of (a) single batteryIs used as a battery cellIs a negative electrode of (a).
Battery cell as described aboveComprising single batterySingle batteryEnergy storage inductance L 3i-1, degaussing resistor R 3i-1, switching tube Q 6i-3 and switching tube Q 6i-2, one end of energy storage inductance L 3i-1 connected in parallel with degaussing resistor R 3i-1 and single batteryIs provided with a negative electrode and a single batteryThe other end of the energy storage inductance L 3i-1 connected in parallel with the degaussing resistor R 3i-1 is connected with one end of the switch tube Q 6i-3 and one end of the switch tube Q 6i-2, and the single batteryThe positive electrode of (a) is connected with the other end of the switch tube Q 6i-3, and a single batteryNegative electrode of (2) and switch tube Q the other end of 6i-2 is connected; single batteryIs used as a battery unitPositive electrode of (a) single batteryIs used as a battery cellIs a negative electrode of (a).
The layered active equalization circuit of retired power battery pack also comprises an LCD lossless absorption network, wherein the LCD lossless absorption network comprises an inductorDiodeDiodeAnd capacitorInductance (inductance)One end of (2) and primary side switch tubeIs connected with one end of the switch K 2i-1, and is an inductorAnd the other end of the diodeIs connected with the cathode of the diodePositive electrode and capacitor of (a)One end of (2) and diodeIs connected with the negative electrode of the capacitorThe other end and the primary side of the switch tubeIs equal to leakage inductanceOne end of the connection is connected with a diodeThe positive pole of which is connected to the primary winding at the end connected to the switch K 2i.
A layered active equalization method of a retired power battery pack utilizes a layered active equalization circuit of the retired power battery pack, which comprises the following steps:
step 1, firstly, balancing the inside of a battery pair;
step2, when all the battery units are Middle single batterySOC value of (c) and single batteryThe absolute value of the difference of the SOC values of (2) is less than or equal to the set in-battery-pair equalization threshold, and when all the battery cells areMiddle single batterySOC value of (c) and single batteryAfter the absolute value of the difference value of the SOC values is smaller than or equal to a set battery in-pair equalization threshold value, carrying out battery in-pair equalization;
Step 3, when all the battery packs are Middle battery unitAverage SOC value of (a) and battery cellAnd (3) after the absolute value of the difference value of the average SOC value is smaller than or equal to a set battery inter-pair equalization threshold value, finally performing inter-group equalization.
The battery in-pair equalization includes battery cells as described aboveIs balanced and battery unit in battery pairIs balanced in the battery pair;
Battery cell The in-cell balance of (a) is: single batteryThe SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-5 is turned on, the switch tube Q 6i-4 is turned off, and the single battery is at the momentThe switching tube Q 6i-5 and the energy storage inductor L 3i-2 form a loop, and the single batteryThe energy of (a) is stored in the energy storage inductor L 3i-2, and the single batteryThe SOC value of (2) decreases; when the single battery is usedWhen charging is started, the switching tube Q 6i-5 is turned off, the switching tube Q 6i-4 is turned on, and the single batteryThe switching tube Q 6i-4 and the energy storage inductance L 3i-2 form a loop, and the energy stored in the energy storage inductance L 3i-2 is transferred to the single batteryIn the battery cellThe SOC value of (2) rises;
Single battery The SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-5 is turned off, the switch tube Q 6i-4 is turned on, and the single batteryThe switching tube Q 6i-4 and the energy storage inductor L 3i-2 form a loop, and the single batteryThe energy of (a) is stored in the energy storage inductor L 3i-2, and the single batteryThe SOC value of (2) decreases; when the single battery is usedDuring charging, the switching tube Q 6i-5 is turned on, the switching tube Q 6i-4 is turned off, and the single batteryThe switching tube Q 6i-5 and the energy storage inductance L 3i-2 form a loop, and the energy stored in the energy storage inductance L 3i-2 is transferred to the single batteryIn the battery cellThe SOC value of (c) rises.
Battery cell as described aboveThe in-cell balance of (a) is: single batteryThe SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-3 is turned on, the switch tube Q 6i-2 is turned off, and the single batteryThe switching tube Q 6i-3 and the energy storage inductor L 3i-1 form a loop, and the single batteryThe energy of (a) is stored in the energy storage inductor L 3i-1, and the single batteryThe SOC value of (2) decreases; when the single battery is usedDuring charging, the switching tube Q 6i-3 is turned off, the switching tube Q 6i-2 is turned on, and the single batteryThe switching tube Q 6i-2 and the energy storage inductance L 3i-1 form a loop, and the energy stored in the energy storage inductance L 3i-1 is transferred to the single batteryIn the battery cellThe SOC value of (2) rises;
Single battery The SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-3 is turned off, the switch tube Q 6i-2 is turned on, and the single batteryThe switching tube Q 6i-2 and the energy storage inductor L 3i-1 form a loop, and the single batteryThe energy of (a) is stored in the energy storage inductor L 3i-1, and the single batteryThe SOC value of (2) decreases; when the single battery is usedDuring charging, the switching tube Q 6i-3 is turned on, the switching tube Q 6i-2 is turned off, and the single batteryThe switching tube Q 6i-3 and the energy storage inductance L 3i-1 form a loop, and the energy stored in the energy storage inductance L 3i-1 is transferred to the single batteryIn the battery cellThe SOC value of (c) rises.
Battery packs as described aboveThe inter-battery equalization of (a) is: battery cellSubtracting the battery cell from the average SOC value of (a)When the difference value of the average SOC values of the battery cells is larger than the set battery inter-pair equalization threshold valueDischarging, switching tube Q 6i-1 is on, switching tube Q 6i is off, and battery unitEnergy is stored in the energy storage inductor L 3i, and the battery unitThe average SOC value of (a) decreases; battery cellAfter the discharge is finished, the battery unitStarting charging, switching tube Q 6i-1 is turned off, switching tube Q 6i is turned on, and energy storage inductor L 3i transfers stored energy to a battery unitIn the battery cellThe average SOC value of (2) rises;
Battery cell Subtracting the battery cell from the average SOC value of (a)When the difference value of the average SOC values of the battery cells is larger than the set battery inter-pair equalization threshold valueDischarging, switching tube Q 6i is on, switching tube Q 6i-1 is off, and battery unitEnergy is stored in the energy storage inductor L 3i, and the battery unitThe average SOC value of (a) decreases; battery cellAfter the discharge is finished, the battery unitStarting charging, switching tube Q 6i is turned off, switching tube Q 6i-1 is turned on, and energy storage inductor L 3i transfers stored energy to a battery unitIn the battery cellThe average SOC value of (a) rises.
Inter-group equalization as described above includes a boost mode and a buck mode;
the boost mode is: battery pack The difference of the average SOC value of the decommissioned power battery pack minus the average SOC value of the decommissioned power battery pack is larger than a set top-layer equalization threshold, and a switch is closedAnd a switchBattery packReleasing energy, battery packPrimary side switch tube connected with primary side of bidirectional flyback transformerConduction and secondary side switch tubeShut down, battery packExcitation inductance with released energy stored in primary winding in the form of magnetic energyIn (a) and (b); up to the primary side switch tubeSwitch-off and secondary side switch tubeIs conducted by the body diode of the primary winding and the exciting inductance of the primary windingThe energy stored in the medium flows to the retired power battery pack and the battery packThe average SOC value of (c) decreases.
The buck mode as described above is: average SOC value of retired power battery minus battery packThe difference value of the average SOC values of (2) is larger than the set top-level equalization threshold value, and the switch is closedAnd a switchRetired power battery pack releases energy, and secondary side switch tubeThe energy released by the power battery pack is stored in the excitation inductor at the secondary side; up to the secondary side switch tubeSwitch-off, primary side switch tubeThe body diode of the transformer is conducted, and the energy stored by the excitation inductance of the secondary side is transferred to the battery group through the bidirectional flyback transformerBattery packThe average SOC value of (a) rises.
Compared with the prior art, the invention has the following beneficial effects:
(1) The two-layer equalization circuit structure of the invention adopts the advantages of combining the inductance with the bidirectional flyback transformer, shortens the equalization path and reduces the equalization time. Meanwhile, the problem that the equalization speed of a single inductance type equalization circuit is low and the problem that the single transformer is difficult to design and high in cost when applied to a long-string retired power battery pack are avoided;
(2) Aiming at the problem of voltage spike caused by leakage inductance of a bidirectional flyback transformer, an LCD lossless absorption network is added into the bidirectional flyback transformer to provide a follow current loop for leakage inductance current, so that soft switching of a power switching tube can be realized while the switching tube is damaged due to overhigh spike voltage, switching loss is reduced, and the working efficiency of the bidirectional flyback transformer is improved.
(3) The combined structure of the switch matrix and the single-magnetic core single-secondary side bidirectional flyback transformer reduces the dependence on multiple windings, and can realize bidirectional energy transmission while reducing devices.
Drawings
FIG. 1 is a circuit block diagram of the present invention;
FIG. 2 (a) is a battery cell of the present invention In-cell-pair equalization of cellsA balanced mode diagram of the discharge;
FIG. 2 (b) is a battery cell of the present invention In-cell-pair equalization of cellsA charged equalization modal map;
FIG. 3 is a battery pack in the underlying equalization circuit of the present invention A circuit schematic diagram of cell pair-to-pair equalization;
FIG. 4 (a) is a battery pack of the present invention operating in Boost mode during n-3 time group equalization A schematic circuit diagram for transmitting to the retired power battery pack;
FIG. 4 (b) shows the energy transfer from a retired power battery pack to a battery pack during n 3-time battery equalization in the Buck mode of the present invention A schematic circuit diagram for carrying out transfer;
FIG. 5 (a) shows a primary side switching tube of the present invention The LCD lossless absorption network under the condition of turn-off works in a circuit schematic diagram of a mode one;
FIG. 5 (b) shows a primary side switching tube of the present invention The LCD lossless absorption network under the condition of turn-off works in a circuit schematic diagram of a second mode;
FIG. 5 (c) shows a primary side switching tube of the present invention The LCD lossless absorption network under the turn-off condition works in a circuit schematic diagram of a third mode;
fig. 6 is a graph showing the result of the equilibrium simulation in a state of rest performed on simulation software using 12 retired batteries under the circuit configuration of the present invention.
Detailed Description
The present invention will be further described in detail below in conjunction with the following examples, which are provided to illustrate and explain the present invention and are not to be limiting, for the purpose of those of ordinary skill in the art.
Example 1:
As shown in fig. 1, a layered active equalization circuit of a retired power battery pack comprises the retired power battery pack, a switch matrix and a bidirectional flyback transformer;
retired power battery pack includes n battery packs N battery packsIs marked as、、…、；i∈{1~n}；
2N battery cellsIs marked as、、····、；
4N single batteryIs marked as、、····、；
3N energy storage inductors L i, which are marked as L 1、L2、····、L3n;
3n demagnetizing resistors R i, denoted as R 1、R2、····、R3n;
6n switching transistors Q i, denoted Q 1、Q2、····、Q6n;
The switch matrix includes 2n switches K i, 2n switches K i denoted K 1,K2、····、K2n;
Battery cell Comprising single batterySingle batteryEnergy storage inductance L 3i-2, degaussing resistor R 3i-2, switching tube Q 6i-5 and switching tube Q 6i-4, one end of energy storage inductance L 3i-2 connected in parallel with degaussing resistor R 3i-2 and single batteryIs provided with a negative electrode and a single batteryThe other end of the energy storage inductance L 3i-2 connected in parallel with the degaussing resistor R 3i-2 is connected with one end of the switch tube Q 6i-5 and one end of the switch tube Q 6i-4, and the single batteryThe positive electrode of (a) is connected with the other end of the switch tube Q 6i-5, and a single batteryNegative electrode of (2) and switch tube Q the other end of 6i-4 is connected; single batteryIs used as a battery unitPositive electrode of (a) single batteryIs used as a battery cellThe control terminal of the switching tube herein is used to control the on and off of the switching tube from "one end" to "the other end".
Battery cellComprising single batterySingle batteryEnergy storage inductance L 3i-1, degaussing resistor R 3i-1, switching tube Q 6i-3 and switching tube Q 6i-2, one end of energy storage inductance L 3i-1 connected in parallel with degaussing resistor R 3i-1 and single batteryIs provided with a negative electrode and a single batteryThe other end of the energy storage inductance L 3i-1 connected in parallel with the degaussing resistor R 3i-1 is connected with one end of the switch tube Q 6i-3 and one end of the switch tube Q 6i-2, and the single batteryThe positive electrode of (a) is connected with the other end of the switch tube Q 6i-3, and a single batteryNegative electrode of (2) and switch tube Q the other end of 6i-2 is connected; single batteryIs used as a battery unitPositive electrode of (a) single batteryIs used as a battery cellIs a negative electrode of (a).
The demagnetizing resistor is connected in parallel with two ends of the energy storage inductor to play a role in preventing magnetic saturation.
Battery packComprising a battery unitBattery unitEnergy storage inductance L 3i, degaussing resistor R 3i, switching tube Q 6i-1 and switching tube Q 6i, one end of energy storage inductance L 3i connected in parallel with degaussing resistor R 3i and battery unitIs provided, and battery cellThe other end of the energy storage inductance L 3i connected in parallel with the degaussing resistor R 3i is connected with one end of the switching tube Q 6i-1 and one end of the switching tube Q 6i, and the battery unitThe positive electrode of (a) is connected with the other end of the switch tube Q 6i-1, and the battery unitNegative electrode of (2) and switch tube Q the other end of 6i is connected; battery cellPositive electrode of (a) as a battery packPositive electrode of (a), battery cellIs used as a battery groupIs a negative electrode of (a).
Battery packPositive electrode of (c) and battery packIs connected with the negative electrode of the battery groupNegative electrode of (c) and battery packPositive electrode connection of battery small groupThe positive pole of (a) is connected with the power bus V BUS, and the battery groupIs grounded (connected to GND);
battery pack The positive electrode of (a) is connected with the primary side switch tube through a switch K 2i-1 Is connected with one end of the primary side switch tubeIs arranged at the other end of the pipe and is leakage inductanceIs connected with one end of the leakage inductanceAnd one end of the primary winding of the bidirectional flyback transformer (excitation inductance of the primary winding of the bidirectional flyback transformer)Is connected with the other end of the primary winding of the bidirectional flyback transformer (the excitation inductance of the primary winding of the bidirectional flyback transformer)The other end of (3) is connected with the battery group through a switch K 2i Is connected to the negative electrode of the battery.
The bidirectional flyback transformer adopts a heteropolarity wiring mode (namely a wiring mode that the polarities of a primary winding and a secondary winding are opposite); the bidirectional flyback transformer adopts a single magnetic core and single secondary side structure.
The layered active equalization circuit of retired power battery pack also comprises an LCD lossless absorption network, wherein the LCD lossless absorption network comprises an inductorDiodeDiodeAnd capacitorInductance (inductance)One end of (2) and primary side switch tubeIs connected with one end of the switch K 2i-1, and is an inductorAnd the other end of the diodeIs connected with the cathode of the diodePositive electrode and capacitor of (a)One end of (2) and diodeIs connected with the negative electrode of the capacitorThe other end and the primary side of the switch tubeIs equal to leakage inductanceOne end of the connection is connected with a diodeOne end of the positive electrode of the primary winding connected to the switch K 2i (excitation inductance of the primary winding)One end connected to the switch K 2i).
Example 2:
The method for layered active equalization of the retired power battery pack, which utilizes the layered active equalization circuit of the retired power battery pack described in the embodiment 1, specifically comprises the following steps:
The balancing of the retired power battery pack comprises bottom layer balancing and top layer balancing, wherein the bottom layer balancing comprises battery in-pair balancing and battery in-pair balancing, and the top layer balancing is inter-group balancing.
Step 1, firstly, balancing the inside of a battery pair;
In-pair battery equalization including battery cells Is balanced and battery unit in battery pairIs balanced in the battery pair;
Battery cell The specific process of the battery in-pair equalization is as follows:
When the single battery is used SOC value of (c) and single batteryWhen the absolute value of the difference value of the SOC values of the battery cells is greater than the set in-pair equalization thresholdPerforming battery pair internal equalization;
Single battery The SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-5 is turned on, the switch tube Q 6i-4 is turned off, and the single battery is at the momentThe switching tube Q 6i-5 and the energy storage inductor L 3i-2 form a loop, and the single batteryStarting discharging, and continuously rising current flowing through two ends of energy storage inductor L 3i-2 to obtain single batteryThe energy of (a) is stored in the energy storage inductor L 3i-2, and the single batteryThe SOC value of (2) decreases; when the single battery is usedWhen charging is started, the switching tube Q 6i-5 is turned off, the switching tube Q 6i-4 is turned on, and the single batteryThe switching tube Q 6i-4 and the energy storage inductance L 3i-2 form a loop, and the energy stored in the energy storage inductance L 3i-2 is transferred to the single batteryIn the battery cellThe SOC value of (c) rises.
Single batteryThe SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-5 is turned off, the switch tube Q 6i-4 is turned on, and the single batteryThe switching tube Q 6i-4 and the energy storage inductor L 3i-2 form a loop, and the single batteryThe energy of (a) is stored in the energy storage inductor L 3i-2, and the single batteryThe SOC value of (2) decreases; when the single battery is usedDuring charging, the switching tube Q 6i-5 is turned on, the switching tube Q 6i-4 is turned off, and the single batteryThe switching tube Q 6i-5 and the energy storage inductance L 3i-2 form a loop, and the energy stored in the energy storage inductance L 3i-2 is transferred to the single batteryIn the battery cellThe SOC value of (c) rises.
When the single battery is usedSOC value of (c) and single batteryWhen the absolute value of the difference between the SOC values is equal to or less than the set in-battery-pair equalization threshold, the battery cellThe battery pair internal equalization is completed;
Battery cell The specific process of the battery in-pair equalization is as follows:
When the single battery is used SOC value of (c) and single batteryWhen the absolute value of the difference value of the SOC values of the battery cells is greater than the set in-pair equalization thresholdPerforming battery pair internal equalization;
Single battery The SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-3 is turned on, the switch tube Q 6i-2 is turned off, and the single batteryThe switching tube Q 6i-3 and the energy storage inductor L 3i-1 form a loop, and the single batteryStarting discharging, and continuously rising current flowing through two ends of energy storage inductor L 3i-1 to obtain single batteryThe energy of (a) is stored in the energy storage inductor L 3i-1, and the single batteryThe SOC value of (2) decreases; when the single battery is usedWhen charging is started, the switching tube Q 6i-3 is turned off, the switching tube Q 6i-2 is turned on, and the single batteryThe switching tube Q 6i-2 and the energy storage inductance L 3i-1 form a loop, and the energy stored in the energy storage inductance L 3i-1 is transferred to the single batteryIn the battery cellThe SOC value of (c) rises.
Single batteryThe SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-3 is turned off, the switch tube Q 6i-2 is turned on, and the single batteryThe switching tube Q 6i-2 and the energy storage inductor L 3i-1 form a loop, and the single batteryThe energy of (a) is stored in the energy storage inductor L 3i-1, and the single batteryThe SOC value of (2) decreases; when the single battery is usedDuring charging, the switching tube Q 6i-3 is turned on, the switching tube Q 6i-2 is turned off, and the single batteryThe switching tube Q 6i-3 and the energy storage inductance L 3i-1 form a loop, and the energy stored in the energy storage inductance L 3i-1 is transferred to the single batteryIn the battery cellThe SOC value of (c) rises.
The battery in-pair equalization threshold can be set according to the requirement, for example, 1%;
When the single battery is used SOC value of (c) and single batteryWhen the absolute value of the difference between the SOC values is equal to or less than the set in-battery-pair equalization threshold, the battery cellThe cell-in-pair equalization of (c) is completed.
Step2, when all the battery units areMiddle single batterySOC value of (c) and single batteryThe absolute value of the difference of the SOC values of (2) is less than or equal to the set in-battery-pair equalization threshold, and when all the battery cells areMiddle single batterySOC value of (c) and single batteryAfter the absolute value of the difference value of the SOC values is smaller than or equal to a set battery in-pair equalization threshold value, carrying out battery in-pair equalization;
battery pack The balancing between the battery pairs is completed, and the specific process is as follows:
When the battery unit Average SOC value of (a) and battery cellWhen the absolute value of the difference value of the average SOC value of the battery is larger than the set balance threshold value between the battery pairs, the battery groupPerforming battery pair-to-pair equalization;
Assume a battery cell Subtracting the battery cell from the average SOC value of (a)When the difference of the average SOC values of the battery cells is larger than the set balance threshold value between the battery pairs, the battery cells are firstly used for balancing the battery cellsStarting discharging, switching tube Q 6i-1 is turned on, switching tube Q 6i is turned off, current flowing through two ends of energy storage inductor L 3i continuously rises, and battery unitEnergy is stored in the energy storage inductor L 3i, and the battery unitThe average SOC value of (a) decreases; battery cellAfter the discharge is finished, the battery unitStarting charging, switching tube Q 6i-1 is turned off, switching tube Q 6i is turned on, and energy storage inductor L 3i transfers stored energy to a battery unitIn the battery cellThe average SOC value of (2) rises;
Battery cell The average SOC value of (a) is the single batterySOC value of (c) and single batteryDividing the sum of SOC values of (2); battery cellThe average SOC value of (a) is the single batterySOC value of (c) and single batteryDividing the sum of SOC values of (2);
The battery inter-pair equalization threshold may be set at self-demand, for example, to 1% or 0.5%.
Battery cellSubtracting the battery cell from the average SOC value of (a)When the difference value of the average SOC values of the battery cells is larger than the set in-pair equalization threshold valueDischarging, switching tube Q 6i is on, switching tube Q 6i-1 is off, and battery unitEnergy is stored in the energy storage inductor L 3i, and the battery unitThe average SOC value of (a) decreases; battery cellAfter the discharge is finished, the battery unitStarting charging, switching tube Q 6i is turned off, switching tube Q 6i-1 is turned on, and energy storage inductor L 3i transfers stored energy to a battery unitIn the battery cellThe average SOC value of (a) rises. .
When the battery unitAverage SOC value of (a) and battery cellWhen the absolute value of the difference value of the average SOC values is smaller than or equal to the set battery inter-pair equalization threshold value, the battery packThe balance among the battery pairs is completed;
Step 3, when all the battery packs are Middle battery unitAverage SOC value of (a) and battery cellAnd (3) after the absolute value of the difference value of the average SOC value is smaller than or equal to a set battery inter-pair equalization threshold value, finally performing inter-group equalization.
The retired power battery pack, the switch matrix and the bidirectional flyback transformer jointly complete inter-group equalization, and the specific process is as follows:
When the inter-group equalization is carried out, the equalization circuit is switched back and forth under the two modes of Boost and Buck according to the average SOC value of the battery pack and the average SOC value of the retired power battery pack. In Boost mode (Boost mode), energy is transferred from the battery group with the highest average SOC value to the retired power battery group, so that the average SOC value of the battery group with the highest average SOC value is reduced; in the Buck mode (step-down mode), energy is transferred from the retired power battery pack to the battery pack having the lowest average SOC value, and the average SOC value of the battery pack having the lowest average SOC value is increased.
Battery packIs the average SOC value of the battery cellAnd battery unitAverage SOC value of (a) dividing the sum by 2; the average SOC value of the retired power battery pack is the sum of the SOC values of all the single batteries divided by the number of the single batteries;
as shown in fig. 4 (a), the equalization process when the top-level equalization circuit operates in Boost mode is: when the battery is assembled The difference of the average SOC value of the retired power battery pack subtracted by the average SOC value is greater than a set top-level equalization threshold, the battery packReleasing energy. First of all the switches in the switch matrix are closedAnd a switchMake the battery small groupPrimary side switch tube connected with primary side of bidirectional flyback transformerConduction and secondary side switch tubeShut down, battery packThe voltage at two ends is added on the primary winding of the bidirectional flyback transformer, the voltage direction of the primary winding is positive and negative (the positive direction of the voltage, namely the current direction, the current is from top to bottom), the voltage direction of the secondary winding is negative and positive from top to bottom (namely the current direction, the current is from top to bottom) due to the opposite polarity of the voltage of the primary winding and the voltage of the secondary winding of the bidirectional flyback transformer, and the secondary switching tubeThe body diode of (2) is in an off state, no current flows through the secondary winding, and the exciting inductance of the primary winding flowsIs continuously increased, and the battery packExcitation inductance with released energy stored in primary winding in the form of magnetic energyIn the middle, up to the primary side switch tubeExcitation inductor when offThe voltage at the two ends is reversed, the voltage direction of the primary winding is changed into positive and negative, the voltage direction of the secondary winding is changed into positive and negative, and the secondary switching tubeIs conducted by the body diode of the primary winding and the exciting inductance of the primary windingThe energy stored in the battery pack flows to the retired power battery pack to complete the battery packEnergy transfer to retired power battery pack, battery packThe average SOC value of (c) decreases.
The top-level equalization threshold may be set at the discretion of the needs, for example to 1% or 0.5%.
The working principle of the Buck mode and the boost mode is the same, as shown in fig. 4 (b), and the balancing process when the top-layer balancing circuit works in the Buck mode is as follows: when the average SOC value of the retired power battery pack subtracts the battery packWhen the difference value of the average SOC values of the (B) is larger than the set top-layer equalization threshold value, the retired power battery pack transmits energy to the battery small pack through the bidirectional flyback transformerMiddle and secondary side switch tubeConduction and switch in switch matrixAnd a switchClosing, the voltage at two ends of the retired power battery pack is applied to the secondary winding of the bidirectional flyback transformer, and the primary winding and the secondary winding of the bidirectional flyback transformer have opposite polarities and the primary switching tubeThe body diode of (c) is in an off state so that no current still flows through the primary winding. The energy released by the retired power battery pack is stored in the excitation inductance of the secondary side until the secondary side switch tubeTurn-off, reverse voltage of the two ends of the excitation inductance of the secondary winding, primary switch tubeThe body diode of the transformer is conducted, and the energy stored by the excitation inductance of the secondary side is transferred to the battery group through the bidirectional flyback transformerBattery packThe average SOC value of (a) rises.
The layered active equalization circuit of retired power battery pack also comprises an LCD lossless absorption network, wherein the LCD lossless absorption network comprises an inductorDiodeDiodeAnd capacitorInductance (inductance)One end of (2) and primary side switch tubeIs connected with one end of the switch K 2i-1, and is an inductorAnd the other end of the diodeIs connected with the cathode of the diodePositive electrode and capacitor of (a)One end of (2) and diodeIs connected with the negative electrode of the capacitorThe other end and the primary side of the switch tubeIs equal to leakage inductanceOne end of the connection is connected with a diodeOne end of the positive electrode of the primary winding connected to the switch K 2i (excitation inductance of the primary winding)One end connected to the switch K 2i);
as shown in fig. 5 (a), 5 (b) and 5 (c), the switching tube is switched on the primary side The three working mode diagrams of the LCD lossless absorption network under the condition of shutdown comprise the following specific steps:
Step S1: working in first working mode, capacitance in the process of group equalization And leakage inductanceAlso stores a certain amount of energy, so when the primary side is switched on and offWhen the valve is closed, the leakage inductance flows throughDoes not abrupt change in current, diodeConducting and capacitanceLeakage inductanceExciting inductanceForm a follow current loop, the capacitorLeakage inductanceExciting inductanceResonance occurs. Initial energy of resonant tankBased on the following formula:
（1）
In the method, in the process of the invention, Is a capacitorThe voltage across the two terminals of the capacitor,To flow through leakage inductanceCurrent of (1), letIs the resonant frequencyBased on the following formula:
（2）
In the resonant current (Flow through leakage inductance)Current of (c) is based on the following formula:
（3）
In the method, in the process of the invention, The time of resonance in the first working mode; the resonant voltage peak value is obtained by combining the formula (1), the formula (2) and the formula (3)(Capacitance)Voltage across the terminals), resonance voltage peakBased on the following formula:
（4）
In the primary side switch tube Drain-source voltage of (2)Based on the following formula:
（5）
In the method, in the process of the invention, Is gradually increased from zero, i.e. primary side switching tubeZero voltage turn-off is achieved.
Step S2: working in working mode two, primary side switch tubeStill turned off, diodeAnd diodeAll are in the cut-off state, the secondary side switch tubeIs turned on by the body diode of (c), at this time, exciting inductanceThe stored energy is transferred to the retired power battery pack through the bidirectional flyback transformer, the retired power battery pack is continuously charged, and the duration of the second working mode is short. Peak resonance voltageThe voltage remains substantially unchanged and remains at the inverse maximum (i.e., the voltage is at its maximum and the voltage direction is opposite to the positive direction).
Step S3: working in working mode three, primary side switch tubeStill in the off state, diodeConduction diodeAnd in the process, the LCD absorption network returns part of energy to the battery group participating in balancing in the third working mode (namely the battery group with the highest average SOC value). The three duration of the working mode is also shorter, and the capacitor is at the endAnd also stores a small amount of energy. The three steps are that the primary side switch tubeThe working principle of the LCD lossless absorption network under the condition of turn-off is used for absorbing the switching tube at the primary sideBy leakage inductance when turned offThe soft switching of the switching tube is realized while the voltage spike is caused, the switching loss is reduced, and the working efficiency of the bidirectional flyback transformer is improved.
In order to more intuitively understand the process of transferring energy between single batteries, fig. 6 is a diagram of an equilibrium simulation result in a static state performed on simulation software (MATLAB/simulink) by using 12 retired batteries under the circuit structure of the present invention; wherein the battery capacity of 12 batteries is 3.8V/2.7Ah, and the initial SOC values of 12 batteries are 51%, 52%, 42%, 45%, 53%, 59%, 63%, 52%, 61%, 60%, 49% and 56% in sequence. As can be seen from fig. 6, the cell-to-cell inconsistency in the initial condition is relatively strong, the cell-to-cell inconsistency after equalization is significantly improved, the equalization time is short, and the equalization speed is fast.
It should be noted that the embodiments described in the present invention are merely illustrative of the spirit of the present invention. Those skilled in the art to which the invention pertains may make various modifications or additions to the described embodiments or substitutions in a similar manner without departing from the spirit of the invention or beyond the scope of the appended claims.
Claims (8)
1. The layered active equalization circuit of the retired power battery pack comprises retired power batteries and is characterized by further comprising a switch matrix and a bidirectional flyback transformer; retired power battery pack includes n battery packsI epsilon { 1-n }, battery groupThe positive electrode of (a) is connected with the primary side switch tube through a switch K 2i-1 Is connected with one end of the primary side switch tubeIs arranged at the other end of the pipe and is leakage inductanceIs connected with one end of the leakage inductanceThe other end of the primary winding of the bidirectional flyback transformer is connected with one end of the primary winding of the bidirectional flyback transformer, and the other end of the primary winding of the bidirectional flyback transformer is connected with the battery group through a switch K 2i Is connected with the negative electrode of the battery;
battery pack Positive electrode of (c) and battery packIs connected with the negative electrode of the battery groupNegative electrode of (c) and battery packPositive electrode connection of battery small groupThe positive pole of (a) is connected with the power bus V BUS, and the battery groupIs grounded; the bidirectional flyback transformer adopts a heteropolarity wiring mode;
battery pack Comprising a battery unitBattery unitEnergy storage inductance L 3i, degaussing resistor R 3i, switching tube Q 6i-1 and switching tube Q 6i, one end of energy storage inductance L 3i connected in parallel with degaussing resistor R 3i and battery unitIs provided, and battery cellThe other end of the energy storage inductance L 3i connected in parallel with the degaussing resistor R 3i is connected with one end of the switching tube Q 6i-1 and one end of the switching tube Q 6i, and the battery unitThe positive electrode of (a) is connected with the other end of the switch tube Q 6i-1, and the battery unitNegative electrode of (2) and switch tube Q the other end of 6i is connected; battery cellPositive electrode of (a) as a battery packPositive electrode of (a), battery cellIs used as a battery groupIs a negative electrode of (a);
The battery pack The inter-battery equalization of (a) is: battery cellSubtracting the battery cell from the average SOC value of (a)When the difference value of the average SOC values of the battery cells is larger than the set battery inter-pair equalization threshold valueDischarging, switching tube Q 6i-1 is on, switching tube Q 6i is off, and battery unitEnergy is stored in the energy storage inductor L 3i, and the battery unitThe average SOC value of (a) decreases; battery cellAfter the discharge is finished, the battery unitStarting charging, switching tube Q 6i-1 is turned off, switching tube Q 6i is turned on, and energy storage inductor L 3i transfers stored energy to a battery unitIn the battery cellThe average SOC value of (2) rises;
Battery cell Subtracting the battery cell from the average SOC value of (a)When the difference value of the average SOC values of the battery cells is larger than the set battery inter-pair equalization threshold valueDischarging, switching tube Q 6i is on, switching tube Q 6i-1 is off, and battery unitEnergy is stored in the energy storage inductor L 3i, and the battery unitThe average SOC value of (a) decreases; battery cellAfter the discharge is finished, the battery unitStarting charging, switching tube Q 6i is turned off, switching tube Q 6i-1 is turned on, and energy storage inductor L 3i transfers stored energy to a battery unitIn the battery cellThe average SOC value of (a) rises.
2. The layered active equalization circuit of a retired power battery of claim 1, wherein the battery cellsComprising single batterySingle batteryEnergy storage inductance L 3i-2, degaussing resistor R 3i-2, switching tube Q 6i-5 and switching tube Q 6i-4, one end of energy storage inductance L 3i-2 connected in parallel with degaussing resistor R 3i-2 and single batteryIs provided with a negative electrode and a single batteryThe other end of the energy storage inductance L 3i-2 connected in parallel with the degaussing resistor R 3i-2 is connected with one end of the switch tube Q 6i-5 and one end of the switch tube Q 6i-4, and the single batteryThe positive electrode of (a) is connected with the other end of the switch tube Q 6i-5, and a single batteryNegative electrode of (2) and switch tube Q the other end of 6i-4 is connected; single batteryIs used as a battery unitPositive electrode of (a) single batteryIs used as a battery cellIs a negative electrode of (a).
3. The layered active equalization circuit of a retired power battery of claim 2, wherein the battery cellsComprising single batterySingle batteryEnergy storage inductance L 3i-1, degaussing resistor R 3i-1, switching tube Q 6i-3 and switching tube Q 6i-2, one end of energy storage inductance L 3i-1 connected in parallel with degaussing resistor R 3i-1 and single batteryIs provided with a negative electrode and a single batteryThe other end of the energy storage inductance L 3i-1 connected in parallel with the degaussing resistor R 3i-1 is connected with one end of the switch tube Q 6i-3 and one end of the switch tube Q 6i-2, and the single batteryThe positive electrode of (a) is connected with the other end of the switch tube Q 6i-3, and a single batteryNegative electrode of (2) and switch tube Q the other end of 6i-2 is connected; single batteryIs used as a battery unitPositive electrode of (a) single batteryIs used as a battery cellIs a negative electrode of (a).
4. A layered active equalization circuit for a retired power battery according to claim 3, further comprising an LCD non-destructive absorption network comprising inductorsDiodeDiodeAnd capacitorInductance (inductance)One end of (2) and primary side switch tubeIs connected with one end of the switch K 2i-1, and is an inductorAnd the other end of the diodeIs connected with the cathode of the diodePositive electrode and capacitor of (a)One end of (2) and diodeIs connected with the negative electrode of the capacitorThe other end and the primary side of the switch tubeIs equal to leakage inductanceOne end of the connection is connected with a diodeThe positive pole of which is connected to the primary winding at the end connected to the switch K 2i.
5. A layered active equalization method for a retired power battery, using a layered active equalization circuit for a retired power battery as set forth in claim 4, comprising the steps of:
step 1, firstly, balancing the inside of a battery pair;
step2, when all the battery units are Middle single batterySOC value of (c) and single batteryThe absolute value of the difference of the SOC values of (2) is less than or equal to the set in-battery-pair equalization threshold, and when all the battery cells areMiddle single batterySOC value of (c) and single batteryAfter the absolute value of the difference value of the SOC values is smaller than or equal to a set battery in-pair equalization threshold value, carrying out battery in-pair equalization;
Step 3, when all the battery packs are Middle battery unitAverage SOC value of (a) and battery cellAfter the absolute value of the difference value of the average SOC value is smaller than or equal to a set battery inter-pair equalization threshold value, finally performing inter-group equalization;
The battery pack The inter-battery equalization of (a) is: battery cellSubtracting the battery cell from the average SOC value of (a)When the difference value of the average SOC values of the battery cells is larger than the set battery inter-pair equalization threshold valueDischarging, switching tube Q 6i-1 is on, switching tube Q 6i is off, and battery unitEnergy is stored in the energy storage inductor L 3i, and the battery unitThe average SOC value of (a) decreases; battery cellAfter the discharge is finished, the battery unitStarting charging, switching tube Q 6i-1 is turned off, switching tube Q 6i is turned on, and energy storage inductor L 3i transfers stored energy to a battery unitIn the battery cellThe average SOC value of (2) rises;
Battery cell Subtracting the battery cell from the average SOC value of (a)When the difference value of the average SOC values of the battery cells is larger than the set battery inter-pair equalization threshold valueDischarging, switching tube Q 6i is on, switching tube Q 6i-1 is off, and battery unitEnergy is stored in the energy storage inductor L 3i, and the battery unitThe average SOC value of (a) decreases; battery cellAfter the discharge is finished, the battery unitStarting charging, switching tube Q 6i is turned off, switching tube Q 6i-1 is turned on, and energy storage inductor L 3i transfers stored energy to a battery unitIn the battery cellThe average SOC value of (a) rises.
6. The method for layered active equalization of a retired power battery pack of claim 5, wherein said in-pair battery equalization comprises battery cellsIs balanced and battery unit in battery pairIs balanced in the battery pair;
Battery cell The in-cell balance of (a) is: single batteryThe SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-5 is turned on, the switch tube Q 6i-4 is turned off, and the single battery is at the momentThe switching tube Q 6i-5 and the energy storage inductor L 3i-2 form a loop, and the single batteryThe energy of (a) is stored in the energy storage inductor L 3i-2, and the single batteryThe SOC value of (2) decreases; when the single battery is usedWhen charging is started, the switching tube Q 6i-5 is turned off, the switching tube Q 6i-4 is turned on, and the single batteryThe switching tube Q 6i-4 and the energy storage inductance L 3i-2 form a loop, and the energy stored in the energy storage inductance L 3i-2 is transferred to the single batteryIn the battery cellThe SOC value of (2) rises;
Single battery The SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-5 is turned off, the switch tube Q 6i-4 is turned on, and the single batteryThe switching tube Q 6i-4 and the energy storage inductor L 3i-2 form a loop, and the single batteryThe energy of (a) is stored in the energy storage inductor L 3i-2, and the single batteryThe SOC value of (2) decreases; when the single battery is usedDuring charging, the switching tube Q 6i-5 is turned on, the switching tube Q 6i-4 is turned off, and the single batteryThe switching tube Q 6i-5 and the energy storage inductance L 3i-2 form a loop, and the energy stored in the energy storage inductance L 3i-2 is transferred to the single batteryIn the battery cellThe SOC value of (c) rises.
7. The method of layered active equalization of a retired power battery of claim 6, wherein the cellsThe in-cell balance of (a) is: single batteryThe SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-3 is turned on, the switch tube Q 6i-2 is turned off, and the single batteryThe switching tube Q 6i-3 and the energy storage inductor L 3i-1 form a loop, and the single batteryThe energy of (a) is stored in the energy storage inductor L 3i-1, and the single batteryThe SOC value of (2) decreases; when the single battery is usedDuring charging, the switching tube Q 6i-3 is turned off, the switching tube Q 6i-2 is turned on, and the single batteryThe switching tube Q 6i-2 and the energy storage inductance L 3i-1 form a loop, and the energy stored in the energy storage inductance L 3i-1 is transferred to the single batteryIn the battery cellThe SOC value of (2) rises;
Single battery The SOC value of (2) minus the cellWhen the difference value of the SOC values of the battery pair is larger than the set internal balance threshold value, the single batteryDischarging, single batteryCharging; when the single battery is usedDuring discharging, the switch tube Q 6i-3 is turned off, the switch tube Q 6i-2 is turned on, and the single batteryThe switching tube Q 6i-2 and the energy storage inductor L 3i-1 form a loop, and the single batteryThe energy of (a) is stored in the energy storage inductor L 3i-1, and the single batteryThe SOC value of (2) decreases; when the single battery is usedDuring charging, the switching tube Q 6i-3 is turned on, the switching tube Q 6i-2 is turned off, and the single batteryThe switching tube Q 6i-3 and the energy storage inductance L 3i-1 form a loop, and the energy stored in the energy storage inductance L 3i-1 is transferred to the single batteryIn the battery cellThe SOC value of (c) rises.
8. The method of layered active equalization of a retired power battery of claim 7, wherein the inter-group equalization includes a boost mode and a buck mode;
the boost mode is: battery pack The difference of the average SOC value of the decommissioned power battery pack minus the average SOC value of the decommissioned power battery pack is larger than a set top-layer equalization threshold, and a switch is closedAnd a switchBattery packReleasing energy, battery packPrimary side switch tube connected with primary side of bidirectional flyback transformerConduction and secondary side switch tubeShut down, battery packExcitation inductance with released energy stored in primary winding in the form of magnetic energyIn (a) and (b); up to the primary side switch tubeSwitch-off and secondary side switch tubeIs conducted by the body diode of the primary winding and the exciting inductance of the primary windingThe energy stored in the medium flows to the retired power battery pack and the battery packThe average SOC value of (a) decreases;
The buck mode is: average SOC value of retired power battery minus battery pack The difference value of the average SOC values of (2) is larger than the set top-level equalization threshold value, and the switch is closedAnd a switchRetired power battery pack releases energy, and secondary side switch tubeThe energy released by the power battery pack is stored in the excitation inductor at the secondary side; up to the secondary side switch tubeSwitch-off, primary side switch tubeThe body diode of the transformer is conducted, and the energy stored by the excitation inductance of the secondary side is transferred to the battery group through the bidirectional flyback transformerBattery packThe average SOC value of (a) rises.
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