CN106300545B - A kind of active equalization control device and control method for liquid metal cell - Google Patents

A kind of active equalization control device and control method for liquid metal cell Download PDF

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Publication number
CN106300545B
CN106300545B CN201610841712.5A CN201610841712A CN106300545B CN 106300545 B CN106300545 B CN 106300545B CN 201610841712 A CN201610841712 A CN 201610841712A CN 106300545 B CN106300545 B CN 106300545B
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soc
liquid metal
metal cell
balanced
control
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CN106300545A (en
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王康丽
朱方方
蒋凯
程时杰
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Huazhong University of Science and Technology
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Huazhong University of Science and Technology
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014Circuits for equalisation of charge between batteries
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014Circuits for equalisation of charge between batteries
    • H02J7/0019Circuits for equalisation of charge between batteries using switched or multiplexed charge circuits

Abstract

The present invention provides a kind of active equalization control device and control method for liquid metal cell, which includes balance module, data acquisition module, SOC computing module and control module;Balance module with by the balanced circuit of balancing battery group composition, it include multiple concatenated liquid metal cells by balancing battery group, the current signal of data collecting module collected liquid metal cell, current signal is transferred to SOC computing module, SOC computing module calculates the SOC of each liquid metal cell, and the SOC of each liquid metal cell is transferred to control module, control module calculates the very poor of SOC according to the SOC of each liquid metal cell, and the driving signal in balanced circuit is controlled according to the very poor output of SOC, driving signal controls the on-off in balanced circuit, realize the equalizaing charge and balanced discharge to liquid metal cell group, it realizes by balancing battery group SOC balance, improve the capacity utilization of battery pack, extend the cycle life of battery pack.

Description

A kind of active equalization control device and control method for liquid metal cell
Technical field
The invention belongs to electrochemical energy storage field, specially a kind of active equalization control device for liquid metal cell and Control method.
Technical background
With the high speed development of global economy, energy and environmental problem is increasingly serious, the scale of renewable energy utilize at For the hot spot of countries in the world research and development.Renewable energy intermittence and wave can be effectively solved by extensive energy storage technology Dynamic property bring problems improve safety, the stability of electric system simultaneously for " peak load shifting " of electric system, Reducing power supply cost has great significance.Liquid metal cell has service life length, capacity as a kind of novel energy-storage battery Greatly, the high advantage of multiplying power has broad application prospects in extensive energy storage field.
Liquid metal cell is a kind of high-temperature battery, and operating temperature positive and negative anodes metal at 300 DEG C~700 DEG C, operation is in Liquid, electrolyte are molten state inorganic salts, inside battery because electrode and electrolyte density difference and due to immiscible characteristic from It is dynamic to be divided into three layers.The structure design of full liquid keeps liquid metal cell mass transfer velocity fast, and battery efficiency is high.Due to having abandoned routine Battery diaphragm, liquid metal cell performance are stablized, are lasted a long time, it is contemplated that the service life 15 years or more.
For applied to extensive energy storage, liquid metal cell must connect to meet the requirement of voltage class, be used in series The inconsistency of battery pack can become larger in the process, due to the presence of battery " short -board effect ", the capacity utilization of battery pack It can significantly reduce, cycle life can also shorten dramatically, it is therefore necessary to Balance route be taken to battery pack to improve the whole of battery pack Body performance.Common energy consumption type shunt resistance equalizing circuit is since energy consumption is high, and euqalizing current is small, and equalization efficiency is low, is not suitable for big The series connection liquid metal cell group of capacity, capacitive equalizing circuit can only realize electric voltage equalization, and liquid metal cell voltage exists It is relatively flat in 10%~90% range of state-of-charge (SOC), and nominal voltage only has 0.9V, therefore even if liquid metal cell When SOC is very poor larger, pressure difference remains unchanged very little between single battery, and along with the conduction voltage drop of switching device, therefore balanced energy is very Hardly possible transfer, or even can not shift, it cannot achieve liquid metal cell SOC balance, cause equalization efficiency low and liquid metal cell Big inconsistency.
Summary of the invention
In view of the foregoing drawbacks, the present invention provides a kind of active equalization control device and controlling party for liquid metal cell Method, it is intended to solve due to liquid metal cell voltage to be 10%~90% very flat to cause to use in liquid metal cell SOC Voltage is the technical issues of balanced variable cannot achieve liquid metal cell SOC balance.
To achieve the above object, the present invention provides a kind of active equalization control device for liquid metal cell, including
Data acquisition module, input terminal are connect with by each liquid metal cell in balancing battery group, for detecting simultaneously Output is by the current signal of each liquid metal cell in balancing battery group;
SOC computing module, input terminal are connected to the current signal output end of the data acquisition module, for according to each The current signal of liquid metal cell calculates the SOC of each liquid metal cell;
Control module, SOC signal input part are connected to the output end of the SOC computing module, the control module Feedback current input terminal is connect with the feedback end of the balance module;For calculating SOC according to the SOC of each liquid metal cell It is very poor, and according to the very poor output drive signal of SOC, and adjust the driving signal in real time according to fed-back current signals;With And
Balance module, have multiple battery terminal connections, respectively with by each liquid metal cell in balancing battery group just Pole is connected with cathode, and the control terminal of the balance module is connected to the driving signal output end of the control module;For passing through It is connected to form balanced circuit with by balancing battery group, and is made according to the driving signal by liquid metal cell in balancing battery group Equalizaing charge and balanced discharge, and the fed-back current signals are exported in real time, realize the transfer of energy between liquid metal cell.
Data acquisition module is detected by liquid metal cell current signal each in balancing battery group, and by collected electricity Stream signal is transferred to SOC computing module, and SOC computing module calculates the SOC of liquid metal cell according to the current signal received, And the SOC signal of liquid metal cell is transferred to control module, control module is according to the liquid gold transmitted by SOC computing module Belong to battery SOC and calculate that SOC is very poor, adjust target value further according to euqalizing current in the very poor determining balanced circuit of SOC, and by liquid Liquid metal cell corresponding to metal battery SOC maximum value is as balanced discharge object, by liquid metal cell SOC minimum value Corresponding liquid metal cell is as equalizaing charge object, according to equalizaing charge object, balanced discharge to picture and balanced electricity Stream adjustment target value determines balance module control terminal driving signal, and is received by feedback current input terminal and fed back by balance module The fed-back current signals for holding output, adjust driving signal in real time, and liquid metal cell passes through balanced circuit equalizaing charge and equilibrium Energy transfer between liquid metal cell is realized in electric discharge, if the very poor of SOC is not zero, control module continues output drive signal, The equalizaing charge and balanced discharge for controlling liquid metal cell, the pole SOC of liquid metal cell is made by energy transfer repeatedly Difference is zero, realizes the SOC balance of liquid metal cell.
Further, the balance module includes two switching tubes, 2n two-way switch pipe and a balanced inductance L;Its In, a switching tube is denoted as switching tube P1, a switching tube is denoted as switching tube Qn+1, n two-way switch pipe be denoted as two-way opened respectively Close pipe P2, two-way switch pipe P3... two-way switch pipe Pn+1, remaining n two-way switch pipe is denoted as two-way switch pipe Q respectively1, it is double To switching tube Q2... two-way switch pipe Qn
The two-way switch pipe PiFirst terminal connects liquid metal cell Ci-1Cathode, the two-way switch pipe PiSecond end Son is connected with equilibrium one end inductance L, the two-way switch pipe QjFirst terminal and liquid metal cell CjAnode connection, it is described double To switching tube QjSecond terminal is connected with the balanced inductance L other end;The two-way switch pipe PiControl terminal and the two-way switch pipe QjControl terminal is connect with the driving signal output end of control module;Wherein, 2 < i < n+1,1 < j < n;
The switching tube P1Cathode is connected with the one end balanced inductance L, the switching tube P1It is positive and positive by balancing battery group Connection;The switching tube Qn+1Anode is connected with the balanced inductance L other end, the switching tube Qn+1Cathode is born with by balancing battery group Pole connection;The switching tube P1Control terminal and the switching tube Qn+1Control terminal connects with the driving signal output end of control module It connects;
The two-way switch pipe can control two-way circulating for electric current, for controlling the disconnection and conducting in balanced circuit, and For preventing liquid metal cell short-circuit;
The switching tube can control electric current and be connected and disconnect from positive to cathode, be used to control the disconnected of balanced circuit It opens and is connected;
Described by balancing battery group includes liquid metal cells that n is sequentially connected in series.
Further, two-way switch pipe includes the first metal-oxide-semiconductor and the second metal-oxide-semiconductor in the balance module, the first metal-oxide-semiconductor Source electrode is connect with the source electrode of the second metal-oxide-semiconductor, and the drain electrode of the first metal-oxide-semiconductor is the first terminal of two-way switch pipe, the leakage of the second metal-oxide-semiconductor The grid of the extremely Second terminal of two-way switch, the grid of the first metal-oxide-semiconductor and the second metal-oxide-semiconductor is all the control of two-way switch pipe End.
Further, the equal metal-oxide-semiconductor of switching tube, anode of the metal-oxide-semiconductor drain electrode for switching tube, the cathode of metal-oxide-semiconductor source switch pipe, Metal-oxide-semiconductor grid is the control terminal of switching tube, and the conducting resistance of metal-oxide-semiconductor is small, can reduce the pressure drop in balancing procedure.
As another object of the present invention, the present invention provides a kind of active equalization control device for liquid metal cell Control method, include the following steps:
(1) current signal of each liquid metal cell is acquired;
(2) SOC of each liquid metal cell is calculated according to the current signal of each liquid metal cell;
(3) to the SOC of each liquid metal cell according to being ranked up from big to small, according to formula Δ SOC=SOCmax- SOCminIt is very poor to calculate SOC, wherein Δ SOC is that SOC is very poor, SOCmaxFor the SOC of maximum liquid metal cell, SOCminFor most The SOC of small liquid metal cell;
(4) if Δ SOC > 0, determine in balanced circuit that euqalizing current adjusts target value according to Δ SOC, and by maximum liquid Liquid metal cell corresponding to metal battery SOC, will be corresponding to minimum liquid metal cell SOC as balanced discharge object Liquid metal cell is as equalizaing charge object;Otherwise (7) are entered step;
(5) target value is adjusted according to balanced discharge object, equalizaing charge object and euqalizing current, determines equilibrium circuit Control signal;
(6) real time equaliser electric current in balanced circuit is detected, and target value is adjusted according to real time equaliser electric current and euqalizing current Correct the control signal in balanced circuit, return step (1);
(7) driving signal for making all liquid metal cells neither discharge nor charge, return step (1) are exported;
It is big according to euqalizing current in the very poor determining balanced circuit SOC using the SOC of liquid metal cell as control variable It is small, it can quickly and accurately realize the equilibrium of liquid metal cell SOC.
Further, pass through formula in the step (2)Calculate liquid metal cell SOC, wherein t is liquid metal pool charging time or discharge time, SOC0For electric discharge initial time or the liquid for the initial time that charges State metal battery SOC, QNFor liquid metal cell capacity, η is coulombic efficiency, and when liquid metal cell electric discharge, η=1, I are Discharge current, and be positive value, when liquid metal cell charging, η < 1, I are charging current, and are negative value.
Further, root according to euqalizing current in the very poor determining balanced circuit of SOC adjusts target in the step (4) Value, comprising the following steps:
(41) as Δ SOC >=0.2, big step equilibrium is carried out using 0.5C euqalizing current, otherwise, enters step (42);
(42) it as 0.1≤Δ SOC < 0.2, carries out becoming step equilibrium using euqalizing current is become, euqalizing current is according to formula IL =44.44 Δ SOC variation, otherwise, enters step (43);
(43) as 0.05≤Δ SOC < 0.1, Conventional equalization is carried out using 0.2C euqalizing current and is otherwise entered step (24);
(44) as 0 < Δ SOC < 0.05, small step equilibrium is carried out using 0.1C euqalizing current, otherwise, is exited according to liquid The process of the very poor determining euqalizing current of metal battery SOC;
Wherein, Δ SOC is that SOC is very poor, ILFor euqalizing current;
According to the very poor size of SOC, variable step equilibrium is carried out using different euqalizing currents, when SOC is very poor very big, is adopted Balanced with big step, rapid drop SOC's is very poor, SOC is very poor gradually become smaller during, gradually change balance policy, can Balancing speed is enough improved, can also guarantee the accuracy of equalization.
Contemplated above technical scheme through the invention, compared with prior art, the invention has the benefit that
1, using the SOC of liquid metal cell as Balance route variable in the present invention, the driving letter of output control balance module Number, and whether it is whether zero as liquid metal cell SOC reach balanced standard using the very poor of SOC, it solves due to liquid Metal battery voltage is 10%~90% very flat to cause to use voltage can not be real for balanced variable in liquid metal cell SOC The problem of liquid metal cell SOC balance.
2, the electric current for passing through real-time detection liquid metal cell in the present invention, calculates the SOC of liquid metal cell, according to Euqalizing current size in the very poor determining balanced circuit SOC, realizes the rate of transfer charge amount between control liquid metal cell, realizes Expeditiously balanced liquid metal pool SOC.
3, by euqalizing current in closed-loop control equilibrium circuit in the present invention, make by balanced liquid metal cell group specified The very poor interior euqalizing current of SOC is constant, improves in balancing procedure by the Stability and dependability of balancing battery group.
4, at balanced initial stage, liquid metal cell SOC difference is big, balanced using big step, rapid drop liquid metal cell SOC difference, phase, liquid metal cell SOC difference are caused by liquid metal cell capacity attenuation is inconsistent after equalization, the difference It is smaller, using small euqalizing current, can be improved the accuracy of equalization, avoid liquid metal cell SOC excessively balanced, promoted balancing speed and The accuracy of equalization, and according to the very poor real-time adjustment balance policy of SOC, also improve balanced inductance work in continuous current mode Weigh speed.
Detailed description of the invention
Fig. 1 is the functional block diagram of active equalization control device provided by the invention;
Fig. 2 for the present invention provide in embodiment equalizing circuit module with by the circuit diagram of balancing battery group;
Fig. 3 is the related figure of liquid metal cell balancing procedure in embodiment provided by the invention: where (a) is equilibrium Current graph is (b) the driving signal figure of equalizaing charge process two-way switch pipe, is (c) balanced discharge process two-way switch pipe Driving signal figure;
Fig. 4 provides the flow chart that euqalizing current is determined in step in embodiment (4) for the present invention;
The simulation model figure of active equalization control device in embodiment is provided in Fig. 5 present invention;
Euqalizing current curve of the battery model under static condition in balancing procedure in embodiment is provided in Fig. 6 present invention Figure;
It provides in embodiment in Fig. 7 present invention by the battery model in balancing procedure under balancing battery group static condition SOC curve graph;
It provides in embodiment in Fig. 8 present invention by the battery model in balancing procedure under balancing battery group charged state SOC curve graph;
The battery for not applied active equalization control in embodiment under balancing battery group charged state is provided in Fig. 9 present invention The SOC curve graph of model.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and It is not used in the restriction present invention.
As shown in Figure 1, provided by the present invention for the active equalization control device of liquid metal cell, including data acquisition Current signal is transferred to SOC meter for acquiring the current signal of liquid metal cell, and by current signal output end by module Module is calculated, the current signal input of SOC computing module and the current signal output end of data acquisition module connect, SOC module The SOC of each liquid metal cell is calculated according to the current signal received, and by SOC signal output end that each liquid is golden The SOC for belonging to battery is transferred to control module, and control module input terminal is connect with SOC computing module SOC signal output end, controls mould Block calculates very poor, the minimum value of the SOC of the very poor maximum value and liquid metal cell for liquid metal cell SOC of SOC of SOC, And using the corresponding liquid metal cell of SOC maximum value of liquid metal cell as balanced discharge object, and liquid metal is electric The corresponding liquid metal cell of SOC minimum value in pond is adjusted as equalizaing charge object according to the very poor determining euqalizing current of SOC Target value adjusts the control terminal that target value determines balance module according to equalizaing charge object, balanced discharge object and euqalizing current Driving signal, the driving signal output end of the control terminal of balance module and control module connects, the connection battery of balance module End is connect with by balancing battery group, forms balanced circuit, and balance module receives driving signal by control terminal, realizes balanced circuit Disconnection and conducting, realize the charge and discharge of liquid metal cell, realize the transfer of liquid metal cell energy, balance module Feedback end exports feedback equalization electric current to control module feedback current input terminal in real time, control module according to feedback equalization electric current with Euqalizing current adjusts the driving signal of target value adjustment output, keeps constant euqalizing current, is conducive to improve by balancing battery The stability of group.The present invention is control variable with liquid metal cell SOC simultaneously, controls balance module according to the very poor output of SOC Driving signal, and whether be zero as liquid metal cell and whether reach the standard of SOC balance solve using the very poor of SOC Since liquid metal cell open-circuit voltage is 10%~90% very flat to cause to use voltage to be equal in liquid metal cell SOC Weigh variable can not real liquid metal cell SOC balance the problem of.
As shown in Fig. 2, balance module and by balancing battery group in embodiment provided by the invention, including switching tube is (wherein, One switching tube is denoted as switching tube P1, another switching tube is denoted as switching tube Qn+1), 2n two-way switch pipe (wherein, n it is two-way Switching tube is denoted as two-way switch pipe P respectively2, two-way switch pipe P3..., two-way switch pipe Pn+1, n two-way switch pipe remember respectively For two-way switch pipe Q1, two-way switch pipe Q2..., two-way switch pipe Qn) and balanced inductance L, it include liquid by balancing battery group Metal battery C1To liquid metal cell Cn, and liquid metal cell C1To liquid metal cell CnIt is sequentially connected in series;
Switching tube P1For metal-oxide-semiconductor, which has the parasitic diode be connected from source electrode to drain electrode, switching tube P1Source electrode with The connection of the one end balanced inductance L, switching tube P1Drain electrode and liquid metal cell C1Anode connection;Two-way switch pipe Pn+1By metal-oxide-semiconductor Z1 With metal-oxide-semiconductor Z2There is the parasitic diode be connected from source electrode to drain electrode, two-way switch pipe P in composition, the metal-oxide-semiconductor2To two-way switch pipe PnWith two-way switch pipe Q1To two-way switch pipe QnStructure and two-way switch pipe Pn+1It is identical, two-way switch pipe Pn+1First terminal It is connected with balanced inductance one end, two-way switch pipe Pn+1Second terminal and liquid metal cell CnCathode is connected, two-way switch pipe P2 To two-way switch pipe PnWith liquid metal cell C1To liquid metal cell CnRelationship is connect with two-way switch pipe Pn+1With liquid metal Battery C1To liquid metal cell CnConnection relationship is identical, two-way switch pipe P2To two-way switch pipe PnWith the connection of balanced inductance L Relationship is the same as two-way switch pipe Pn+1It is identical as the connection relationship of balanced inductance L.
Switching tube Qn+1For metal-oxide-semiconductor, which has the parasitic diode be connected from source electrode to drain electrode, switching tube Qn+1Leakage Pole is connected with the balanced inductance L other end, switching tube Qn+1Source electrode and liquid metal cell C1Cathode is connected;Two-way switch pipe QnFirst Terminal and liquid metal cell CnAnode is connected, two-way switch pipe QnSecond terminal is connected with the balanced inductance L other end, two-way opened Close pipe Q1Extremely to switching tube Qn-1With liquid metal cell C1To liquid metal cell CnConnection relationship is the same as two-way switch pipe QnWith liquid State metal battery C1To liquid metal cell CnConnection relationship is identical, two-way switch pipe Q1To two-way switch pipe Qn-1With balanced inductance The connection relationship of L is the same as two-way switch pipe QnIt is identical as the connection relationship of balanced inductance L.
Switching tube uses metal-oxide-semiconductor, it is small to can use its saturation conduction resistance, to reduce pressure drop in balancing procedure, simultaneously The two-way switch pipe being connected in series by two metal-oxide-semiconductors can be realized the double-direction control to electric current, while can prevent from posting due to metal-oxide-semiconductor The presence of raw diode causes by balancing battery group short circuit.Consider switching interval in balancing procedure, it is balanced terminate and by Working conditions, the inductive currents such as balancing battery group is out of service can pass through switching tube P1, switching tube Qn+1Middle parasitic diode into Row afterflow, and avoid generating due to voltage spikes breakdown switch pipe.
Data acquisition module is detected by liquid metal cell C in balancing battery group1To liquid metal cell CnElectric current letter Number, collected current signal is transferred to SOC computing module by data acquisition module, calculates liquid gold by SOC computing module Belong to battery C1To liquid metal cell CnSOC, and the SOC signal of liquid metal cell is transferred to control module, it is assumed that at this time The maximum value of the SOC of liquid metal cell corresponds to liquid metal cell C2, the minimum value of the SOC of liquid metal cell corresponds to liquid Metal battery Cn, then liquid metal cell C2For equalizaing charge object, liquid metal cell CnFor balanced discharge object, and calculate SOC's is very poor, according to the very poor determining euqalizing current of SOC, and exports the driving signal of control balance module, control module generates Driving signal makes two-way switch Q2Along liquid metal cell C2Anode is connected to the direction balanced inductance L, makes two-way switch P3Along Balanced inductance L is to liquid metal cell C2Negative electrode side is to conducting, liquid metal cell C2, two-way switch pipe Q2, equilibrium inductance L and Two-way switch pipe P3Constitute balanced circuit, liquid metal cell C2Discharged by balanced circuit to balanced inductance L, euqalizing current by Gradually rise, after rising to certain value, driving signal makes two-way switch pipe Q2With two-way switch pipe P3It is turned off, makes switching tube Qn+1 Along liquid metal cell CnCathode is connected to balanced inductance, two-way switch pipe PnAlong balanced inductance to liquid metal cell Cn Anode conducting, liquid metal cell Cn, switching tube Qn+1, equilibrium inductance L and two-way switch pipe PnConstitute balanced circuit, balanced inductance L passes through balanced circuit to electric liquid metal cell CnCharging.
As shown in Fig. 3 (b), PWM 1 is liquid metal cell C2Two-way switch pipe Q during balanced discharge2And two-way switch Pipe P3Control signal, as shown in Fig. 3 (c), PWM 2 be liquid metal cell CnTwo-way switch pipe Q during equalizaing chargen+1With Two-way switch pipe PnControl signal allow two-way switch pipe Q as shown in Fig. 3 (a)2With two-way switch pipe P3Conducting, liquid metal Battery C2Electric discharge, euqalizing current is gradually increasing, and when euqalizing current rises to certain value, makes two-way switch pipe Q2With to switching tube P3 Cut-off, makes two-way switch pipe PnWith switching tube Qn+1Conducting, inductance L is to liquid metal cell C at this timenCharging, euqalizing current is gradually It reduces.If the turn-on time of two-way switch pipe and two-way switch pipe is reduced, euqalizing current minor swing may be implemented, be conducive to by The stability of balancing battery group.
The present invention provides a kind of control method of active equalization control device for liquid metal cell, including it is following Step:
(1) each liquid metal cell and current signal are acquired;
(2) SOC of each liquid metal cell is calculated according to the electric current of each liquid metal cell;Liquid metal cell SOC is for the control variable as active equalization control method;
(3) to the SOC of each liquid metal cell according to being ranked up from big to small, according to formula Δ SOC=SOCmax- SOCminIt is very poor to calculate SOC, wherein Δ SOC is that SOC is very poor, SOCmaxFor the SOC of maximum liquid metal cell, SOCminFor most The SOC of small liquid metal cell;
(4) if Δ SOC > 0, determine in balanced circuit that euqalizing current adjusts target value according to Δ SOC, and by maximum liquid Liquid metal cell corresponding to metal battery SOC, will be corresponding to minimum liquid metal cell SOC as balanced discharge object Liquid metal cell is as equalizaing charge object;Otherwise (7) are entered step;Target value is adjusted with the very poor determining euqalizing current of SOC, And using the minimum and maximum corresponding liquid metal cell of liquid metal cell SOC as balanced discharge object and equalizaing charge pair As can quickly and accurately realize the SOC balance of liquid metal cell.
(5) target value is adjusted according to balanced discharge object, equalizaing charge object and euqalizing current, determines equilibrium circuit Control signal;
(6) real time equaliser electric current in balanced circuit is detected, and target value is adjusted according to real time equaliser electric current and euqalizing current Correct the control signal in balanced circuit, return step (1);Closed-loop control is carried out to euqalizing current, guarantees euqalizing current specified It is constant in very poor, be conducive to improve by the stability of balancing battery group.
(7) the control signal in balanced circuit is to make all liquid metal cells and do not discharge also not charge, return step (1)。
In another embodiment provided by the invention, liquid metal cell SOC, formula are calculated using current integration method are as follows:
Wherein, t is liquid metal pool charging time or discharge time, SOC0For electric discharge initial time or charging initial time Liquid metal cell SOC, QNFor liquid metal cell capacity, η is coulombic efficiency, when liquid metal cell electric discharge, η=1, I is discharge current, and is positive value, and when liquid metal cell charging, η < 1, I are charging current, and is negative value.
As shown in figure 4, according to the very poor of liquid metal cell SOC in step (2) in another embodiment provided by the invention Determine euqalizing current, comprising the following steps:
(21) as Δ SOC >=0.2, big step equilibrium is carried out using 0.5C euqalizing current, otherwise, enters step (22);
(22) as 0.1≤Δ SOC < 0.2, equilibrium is walked using the change for becoming euqalizing current, euqalizing current is according to formula IL= 44.44 Δ SOC variation, otherwise, enters step (23);
(23) as 0.05≤Δ SOC < 0.1, Conventional equalization is carried out using 0.2C euqalizing current and is otherwise entered step (24);
(24) as 0 < Δ SOC < 0.05, small step equilibrium is carried out using 0.1C euqalizing current, otherwise, is exited according to liquid The process of the very poor determining euqalizing current of metal battery SOC;
Δ SOC is the difference of maximum liquid metal cell SOC and the smallest liquid metal cell SOC.
It is very poor for different SOC, using different balance policies, at balanced initial stage, the SOC difference of liquid metal cell Greatly, big step equilibrium is carried out using big euqalizing current, quickly reduces the SOC difference of liquid metal cell, in the balanced prometaphase, liquid The SOC difference of metal battery is balanced reduced due to walking greatly, at this time using the very poor determining euqalizing current according to SOC, avoid by Change too fast influence by the stability of balancing battery group in euqalizing current, mid-term, uses Conventional equalization, equal at this time after equalization Weigh the later period, as liquid metal cell capacity attenuation it is inconsistent caused by liquid metal cell SOC difference, the SOC difference is small, adopts It is balanced with the small step of small euqalizing current, it can be improved the accuracy of equalization, avoid liquid metal cell SOC excessively balanced, using different equal Weighing apparatus electric current promotes balancing speed and the accuracy of equalization simultaneously, in addition, the curent change span in balanced inductance is small to make balanced inductance work Make to improve balancing speed in continuous current mode.
As shown in figure 5, utilizing MATLAB/SIMULINK simulation software in the present embodiment, the master of liquid metal cell is built The model of dynamic equalising control device carries out simulating, verifying.
It include concatenated battery model 1, battery model 2 and battery model 3 by balancing battery group, battery model 1 exports electricity Pressure is V1, and the SOC initial value of battery model 1 is SOC1, and 2 output voltage of battery model is V2, the SOC initial value of battery model 2 For SOC2,3 output voltage of battery model is V3, and the SOC initial value of battery model 3 is SOC3.Battery model 1 is to battery model 3 Nominal voltage be 0.9V, rated capacity is 20Ah, and battery model 1 to battery model 3 is by mixed pulses power Performance test and the second order thevenin equivalent circuit model for carrying out parameter identification foundation, battery model 1 to battery model 3 can be counted Respective real-time SOC is calculated, and exports the SOC of real-time battery model by the port SOC.
Equalizing circuit, including the balanced inductance of two switching tubes, six two-way switch pipes and one, pass through the electricity of equalizing circuit Pressure input terminal is connected with three battery model voltage output ends, make equalizing circuit with by the balanced circuit of balancing battery composition.
The very poor module of SOC, the very poor module of SOC are very poor and very poor by SOC by acquiring each battery model SOC calculating SOC Oscilloscope display SOC is very poor.
Control module includes equalizaing charge controller and device for controlling equalized-discharge, and device for controlling equalized-discharge is for controlling liquid Metal battery passes through the process of balanced circuit balanced discharge, and equalizaing charge controller passes through equilibrium for controlling liquid metal cell The process of circuit equalizaing charge according to the very poor determining euqalizing current of hydraulic pressure metal battery SOC and needs to access in balanced circuit Hydraulic pressure metal battery, generate the driving signal PMW1 to PWM4 of switching tube in equalizing circuit and acquire in ultramagnifier balanced electricity Stream adjusts driving signal PWM1 to PWM4 in real time.
When external charge electric current is zero, indicate to be in static condition by balancing battery group.When external charge electric current is greater than zero When, it indicates to be in charged state by balancing battery group.
The very poor oscillograph of SOC is very poor for real-time display SOC, and euqalizing current oscillograph is used for real-time display euqalizing current.
Simulation implementation example one:
The SOC initial value that battery model 1 is arranged is 80%, and the SOC initial value of setting battery model 2 is 70%, setting electricity The SOC initial value of pool model 3 is 75%, and setting external charge electric current is zero, i.e., is in static condition by balancing battery group, according to The very poor control euqalizing current of battery model SOC, as shown in fig. 6, SOC is very poor between 0.05 to 0.1 at balanced initial stage, it is balanced Current average is 4A;In the balanced later period, SOC is very poor between 0 to 0.05, and euqalizing current average value is 2A;Simulating, verifying is carried out, It is illustrated in figure 7 balancing procedure battery model SOC change curve under static condition, it is about basic in each battery model SOC value of 2715s Unanimously, battery model SOC value is about 74.65%.Whole process, equalization efficiency are about 81.58%.Initial by balancing battery group After SOC reaches unanimity, balance control system is balanced using small step, is still able to maintain by the consistency of balancing battery group SOC, And in each very poor range of SOC, the stabilization of inductive current is conducive to attenuation systems fluctuation.Simulation result shows active equalization control Device processed can be realized to by quick, the efficient equilibrium of balancing battery group, to improve by the consistency and appearance of balancing battery group Measure utilization rate.
Simulation implementation example two:
The SOC initial value that battery model 1 is arranged is 35%, and the SOC initial value of setting battery model 2 is 40%, setting electricity The SOC initial value of pool model 3 is 45%, and setting external charge electric current is greater than zero, i.e., is in charged state by balancing battery group, right It is above-mentioned to be controlled by balancing battery group application active equalization, single battery SOC change curve is obtained as shown in figure 8, big as seen from the figure It is about reached unanimity substantially in 2672S by balancing battery group SOC, is about 98% by balancing battery group SOC in 4000S.
Simulation comparison embodiment one:
The SOC initial value that battery model 1 is arranged is 35%, and the SOC initial value of setting battery model 2 is 40%, setting electricity The SOC initial value of pool model 3 is 45%, and setting charging current is 10A, is controlled active equalization is not applied by balancing battery group, Fig. 9 be by balancing battery group in the charge state not to by balancing battery group carry out Balance route battery model SOC curve graph, It does not control by balancing battery group progress active equalization, in 3786S, by balancing battery group charge cutoff, battery model 1 to electricity The SOC of pool model 3 is followed successively by 0.9%, 0.95%, 1.0%, still very big by the inconsistency of balancing battery group.Battery model 1 It is first filled, battery model 2 and battery model 3 can still be filled with certain electricity at this time, but since battery model 1 is full of, need to stop It charges, causes low by the balancing battery pack charge capacity charging capacity more total than all battery models to by balancing battery group.
Emulation embodiment two applies less being applied by balancing battery group for active equalization control compared with simulation comparison example one Balance route by the balancing battery group constant-current charge time it is longer, obviously mentioned by the consistency of balancing battery group and capacity utilization Height illustrates that the active equalization control device can be realized in the charge state and is formed to by concatenated liquid metal by balancing battery By balancing battery group fast uniform.
As it will be easily appreciated by one skilled in the art that the foregoing is merely illustrative of the preferred embodiments of the present invention, not to The limitation present invention, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should all include Within protection scope of the present invention.

Claims (7)

1. a kind of active equalization control device for liquid metal cell characterized by comprising
Data acquisition module, input terminal are connect with by each liquid metal cell in balancing battery group, for acquiring by balanced electricity The current signal of each liquid metal cell of Chi Zuzhong;
SOC computing module, input terminal are connected to the current signal output end of the data acquisition module, for according to each liquid The current signal of metal battery calculates the SOC of each liquid metal cell;
Control module, SOC signal input part are connected to the output end of the SOC computing module, the feedback of the control module The connection of the feedback end of current input terminal and balance module;For very poor according to the SOC of each liquid metal cell calculating SOC, and root Target value is adjusted according to the very poor determining euqalizing current of SOC, and defeated according to real time equaliser electric current and euqalizing current adjustment target value adjustment Driving signal out;And
Balance module, have multiple battery terminal connections, respectively with by balancing battery group each liquid metal cell anode and it is negative Pole connection;The control terminal of the balance module is connected to the driving signal output end of the control module, for by with it is equal Weighing apparatus battery pack is connected to form balanced circuit, and makes to be filled by liquid metal cell equilibrium in balancing battery group according to the driving signal Electricity and balanced discharge realize the transfer of energy between liquid metal cell;The feedback end of the balance module is fed back to control module Current input terminal real time equaliser electric current;
It is described that target value is adjusted according to the very poor determining euqalizing current of SOC, it specifically includes:
As Δ SOC >=0.2, it is balanced that big step is carried out using big euqalizing current;It is balanced using becoming as 0.1≤Δ SOC < 0.2 Electric current carries out becoming step equilibrium;As 0.05≤Δ SOC < 0.1, using Conventional equalization;As 0 < Δ SOC < 0.05, use is small It is balanced that euqalizing current carries out small step, wherein Δ SOC is that SOC is very poor.
2. active equalization control device according to claim 1, which is characterized in that the balance module includes two switches The balanced inductance L of pipe, 2n two-way switch pipe and one;Wherein, a switching tube is denoted as switching tube P1, another switching tube is denoted as Switching tube Qn+1, n two-way switch pipe be denoted as two-way switch pipe P respectively2, two-way switch pipe P3... two-way switch pipe Pn+1, remain Remaining n two-way switch pipe is denoted as two-way switch pipe Q respectively1, two-way switch pipe Q2... two-way switch pipe Qn
The two-way switch pipe PiFirst terminal connects liquid metal cell Ci-1Cathode, the two-way switch pipe PiSecond terminal and The one end balanced inductance L is connected, the two-way switch pipe QjFirst terminal and liquid metal cell CjAnode connection, the two-way opened Close pipe QjSecond terminal is connected with the balanced inductance L other end;The two-way switch pipe PiControl terminal and the two-way switch pipe QjControl End processed is connect with the driving signal output end of control module;Wherein, 2 < i < n+1,1 < j < n;
The switching tube P1Cathode is connected with the one end balanced inductance L, the switching tube P1Anode connects with by balancing battery group anode It connects;The switching tube Qn+1Anode is connected with the balanced inductance L other end, the switching tube Qn+1Cathode with by balancing battery group cathode Connection;The switching tube P1Control terminal and the switching tube Qn+1Control terminal is connect with the driving signal output end of control module;
The two-way switch pipe can control two-way circulating for electric current, for controlling the disconnection and conducting in balanced circuit, and be used for Prevent liquid metal cell short-circuit;
The switching tube can control electric current and circulate from positive to cathode, be used to control the disconnection and conducting in balanced circuit;
Described by balancing battery group includes liquid metal cells that n is sequentially connected in series.
3. active equalization control device according to claim 2, which is characterized in that two-way switch pipe in the balance module Including the first metal-oxide-semiconductor and the second metal-oxide-semiconductor, the source electrode of the first metal-oxide-semiconductor is connect with the source electrode of the second metal-oxide-semiconductor, the drain electrode of the first metal-oxide-semiconductor For the first terminal of two-way switch pipe, the drain electrode of the second metal-oxide-semiconductor is the Second terminal of two-way switch, the grid of the first metal-oxide-semiconductor and The grid of second metal-oxide-semiconductor is all the control terminal of two-way switch pipe.
4. active equalization control device according to claim 2, which is characterized in that switching tube is metal-oxide-semiconductor, metal-oxide-semiconductor leakage The extremely anode of switching tube, metal-oxide-semiconductor source electrode are the cathode of switching tube, and metal-oxide-semiconductor grid is the control terminal of switching tube.
5. a kind of control method for the active equalization control device of liquid metal cell as described in claim 1, It is characterized in that, includes the following steps:
(1) current signal of each liquid metal cell is acquired;
(2) SOC of each liquid metal cell is calculated according to the current signal of each liquid metal cell;
(3) to the SOC of each liquid metal cell according to being ranked up from big to small, according to formula Δ SOC=SOCmax-SOCminMeter It is very poor to calculate SOC, wherein Δ SOC is that SOC is very poor, SOCmaxFor liquid metal cell SOC maximum value, SOCmin
For liquid metal cell SOC minimum value;
(4) if Δ SOC > 0, determine in balanced circuit that euqalizing current adjusts target value according to Δ SOC, and by maximum liquid metal Liquid metal cell corresponding to battery SOC is as balanced discharge object, by liquid corresponding to minimum liquid metal cell SOC Metal battery is as equalizaing charge object;Otherwise (7) are entered step;
(5) target value is adjusted according to balanced discharge object, equalizaing charge object and euqalizing current, determines the control in equilibrium circuit Signal;
(6) real time equaliser electric current in balanced circuit is detected, and according to real time equaliser electric current and euqalizing current adjustment target value amendment The control signal in balanced circuit, return step (1);
(7) output makes the driving signal of all liquid metal cells neither balanced discharge also Unbalance charging, return step (1);
It is described that target value is adjusted according to the very poor determining euqalizing current of SOC, it specifically includes:
As Δ SOC >=0.2, it is balanced that big step is carried out using big euqalizing current;It is balanced using becoming as 0.1≤Δ SOC < 0.2 Electric current carries out becoming step equilibrium;As 0.05≤Δ SOC < 0.1, using Conventional equalization;As 0 < Δ SOC < 0.05, use is small It is balanced that euqalizing current carries out small step, wherein Δ SOC is that SOC is very poor.
6. control method according to claim 5, which is characterized in that pass through formula in the step (2)Calculate the SOC of liquid metal cell, wherein t is the liquid metal pool charging time or puts Electric time, SOC0For electric discharge initial time or the liquid metal cell SOC, Q of the initial time that chargesNFor liquid metal cell capacity, η is coulombic efficiency, and when liquid metal cell electric discharge, η=1, I are discharge current, and is positive value, when liquid metal cell charges When, η < 1, I are charging current, and are negative value.
7. control method according to claim 5, which is characterized in that very poor determining balanced according to SOC in the step (4) Euqalizing current adjusts target value in circuit, comprising the following steps:
(41) as Δ SOC >=0.2, big step equilibrium is carried out using 0.5C euqalizing current, otherwise, enters step (42);
(42) it as 0.1≤Δ SOC < 0.2, carries out becoming step equilibrium using euqalizing current is become, euqalizing current is according to formula IL= 44.44 Δ SOC variation, otherwise, enters step (43);
(43) as 0.05≤Δ SOC < 0.1, Conventional equalization is carried out using 0.2C euqalizing current and otherwise enters step (44);
(44) as 0 < Δ SOC < 0.05, small step equilibrium is carried out using 0.1C euqalizing current, otherwise, is exited according to liquid metal The process of the very poor determining euqalizing current of battery SOC;
Wherein, Δ SOC is that SOC is very poor, ILFor euqalizing current.
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