CN103730936B - The balanced management method of electric automobile power battery balanced management system - Google Patents

The balanced management method of electric automobile power battery balanced management system Download PDF

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CN103730936B
CN103730936B CN201410002969.2A CN201410002969A CN103730936B CN 103730936 B CN103730936 B CN 103730936B CN 201410002969 A CN201410002969 A CN 201410002969A CN 103730936 B CN103730936 B CN 103730936B
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battery
voltage
battery module
cell
microcontroller
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CN103730936A (en
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张向文
崔继友
许勇
党选举
伍锡如
莫太平
潘明
任风华
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Guilin University of Electronic Technology
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Guilin University of Electronic Technology
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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Abstract

Electric automobile power battery balanced management system of the present invention and balanced management method, the cell of native system battery pack is divided into the individual identical battery module of M by series sequence, each battery module connects each resistance, electric capacity equalizing circuit respectively, and coaxial Multiple coil DC-DC converter.Microcontroller is connected with battery management system and obtains power battery pack status data, and the signal of microcontroller connects each electric capacity, resistance equalizing circuit, and connects pulse driver unit and converter.This balanced management method, microcontroller first obtains battery pack nominal parameter, determines controling parameters.Obtain current operation variable again, calculate the maximal deviation sum voltage decentralization of voltage between battery module.By battery pack charging, leave standstill and the different conditions of electric discharge, select to start the different criterions of equalization operation, carry out the equilibrium of intermodule with converter, electric capacity, resistance equalizing circuit carry out the equilibrium between monomer.The multiple equalizing circuit of the present invention is had complementary advantages, and improves balancing speed and efficiency.

Description

The balanced management method of electric automobile power battery balanced management system
Technical field
The present invention relates to the power control technology field of new-energy automobile, be specially a kind of electric automobile power battery balanced management system and balanced management method.
Background technology
At present, new-energy automobile is the focus of development of automobile research, electric automobile emphasis more wherein.Power battery pack is the critical component of restriction electric vehicle industrialization process.There is " wooden pail effect " in power battery pack, namely battery pack and performance are determined by wherein the poorest battery, and therefore the consistency of battery in battery pack is one of key index judging battery performance quality.Study battery balanced management system and become the necessary means solving battery in battery pack inconsistency.But, domestic and international battery balanced administrative skill mainly concentrates in the management to battery pack entirety, judge that whether its battery charging and discharging completes according to battery pack cut-ff voltage, the basic demand of electric automobile can only be met, effectively can not solve the harmful effect that battery inconsistency causes.
Now there is the report of electrokinetic cell balanced management method, as 2011, Li Pinghe He Minghua in 2011, the 35th phase " power technology " 1214-1217 page is published an article " a kind of lithium battery pack equalizing circuit and control strategy design thereof ", this article devises a kind of energy transfer equalizing circuit, realize the two-way transfer of energy, in control strategy, use heuristic search algorithm to plan energy transfer pathway, but this equalization methods realize more complicated.The energy transfer equalizing circuit of its design utilizes the energy-storage travelling wave tube such as electric capacity, inductance as energy transition, energy is transferred to the low monomer of energy from the monomer that energy is high, realizes the equilibrium of battery pack self-energy.But difficulty of matching is large in the circuit of reality, and electromagnetic interference is serious, and battery pack self-energy transfer equilibrium is difficult to realize.Although search balancing energy path by complicated algorithm can improve balancing speed and equalization efficiency to a certain extent, when number of monomers is many time, obvious this algorithm amount of calculation is very large, increases the weight of the burden of MCU, and balancing speed can significantly decline.
The problem of more complicated is realized in order to overcome above-mentioned equalization methods, notification number is CN202127255, name is called that the scheme of the utility model patent proposition of " a kind of power battery full-balance controller for electric automobile " is the dump energy situation according to battery, automatic switchover balanced mode, when dump energy is less than or equal to 30% time, MCU external active equalization control circuit is the cell charging that electricity is minimum; When dump energy is more than or equal to 70% time, MCU utilizes external passive equalizing circuit gating metal-oxide-semiconductor, is the cell electric discharge that electricity is the highest; When dump energy is between 30%-70%, MCU opens active equalization circuit and passive equalizing circuit simultaneously.The scheme of this patent, on the basis not increasing too many hardware cost, had both completed the conforming operation of electrokinetic cell, had also reduced power consumption.Although this patent reduces the complexity of equalization methods to a certain extent, but be based on passive equalizing circuit when implementing, reduce balancing speed and equalization efficiency, and adopting unitary variant---battery dump energy is as the Rule of judgment of equalization operation, have ignored cell operating status and electric automobile during traveling state to the impact of equalization operation, battery balanced situation can not be reflected fully effectively.
Summary of the invention
The object of the invention is to design a kind of electric automobile power battery balanced management system, the cell of connecting in electric automobile power battery group is divided into multiple identical module, each battery module connects the equilibrium that with it corresponding resistance balance module and electric capacity balance module carry out between cell respectively, and coaxial Multiple coil DC-DC converter connects the equilibrium that each battery module carries out between battery module.Microcontroller contact resistance balance module and electric capacity balance module, coaxial Multiple coil DC-DC converter connects voltage acquisition comparison circuit, and the output of voltage acquisition comparison circuit connects microcontroller.Microcontroller connects battery management system through field control technology bus.
Another object of the present invention designs the balanced management method of above-mentioned electric automobile power battery balanced management system, microcontroller obtains battery voltage, electric current, battery pack dump energy and monomer battery voltage data from battery management system, according to the operating state of battery and the operation conditions of electric automobile, select corresponding equalization operation criterion; According to the voltage difference between voltage difference between cell or battery module, calculate balanced step-length; After a balanced step-length operation, battery standing a period of time, after cell voltage is basicly stable, then start the equalization operation of next stage.
The electric automobile power battery balanced management system of the present invention's design, comprises microcontroller, and this battery balanced management system is connected with battery management system, and battery management system is furnished with the testing circuit of the current operational factor obtaining power battery pack.Cell in native system electric automobile power battery group is divided into the individual identical battery module of M by series sequence, and 2≤M≤40, comprise m cell 2≤m≤8 in each battery module.Each battery module connects resistance equalizing circuit corresponding with it and electric capacity equalizing circuit respectively, and coaxial Multiple coil DC-DC converter is connected with each battery module.
Described microcontroller is connected with battery management system through field control technology bus (Controller Area Network, CAN), obtains the nominal parameter of power battery pack and the battery status data of current operating parameter, and stores.The signal output part of microcontroller connects the control end of each electric capacity equalizing circuit and resistance equalizing circuit respectively through electronic switch array, namely microcontroller connects through electronic switch array or cuts out the electric capacity equalizing circuit corresponding with certain battery module or resistance equalizing circuit.One road signal access pulse driver unit of microcontroller, the pulse-width signal that pulse driver unit exports is connected each control end of coaxial Multiple coil DC-DC converter with the control signal that microcontroller exports.
Resistance equalizing circuit and electric capacity equalizing circuit are used for realizing bottom equilibrium, the equilibrium namely in battery module between cell; Coaxial Multiple coil DC-DC converter is used for realizing top layer equilibrium, balanced namely between module with module.
Described coaxial Multiple coil DC-DC converter comprises transformer, power switch unit, rectifier diode and filter capacitor.Converter is inverse-excitation type structure; The number of transformer secondary is that the number of turn of the number M of battery module, a M secondary is identical; The input one end on former limit connects the positive pole of battery pack, the other end is connected to ground through a power switch, every road secondary output port is connected the two ends of filter capacitor respectively with a rectifier diode through a power switch unit, filter capacitor and corresponding battery module parallel connection of each secondary, the control signal of microcontroller connects pulse driver unit, control the duty ratio of the pulse-width signal that it exports, pulse driver unit signal output part connects the power switch unit on former limit.The signal end of microcontroller also connects the power switch unit of each secondary connection, controls its conducting and shutoff.
The former limit input voltage (i.e. the output voltage of battery pack) of coaxial Multiple coil DC-DC converter is connected with end of oppisite phase with the in-phase end of voltage acquisition comparison circuit respectively with a certain road secondary output voltage, and the output of voltage acquisition comparison circuit is connected with microcontroller.Microcontroller is by the output signal of voltage acquisition comparison circuit, judge the relation of coaxial Multiple coil DC-DC converter input voltage and output voltage, and then regulable control signal makes coaxial Multiple coil DC-DC converter input and each road secondary exports in strict linear relationship, realizes voltage between each battery module and reaches consistent.
Described resistance equalizing circuit comprises discharge resistance and field effect transistor, described discharge resistance number and field effect transistor number equal cell number m in battery module, the i.e. corresponding discharge resistance of each cell and a field effect transistor, each cell connects the discharge resistance of its correspondence through the field effect transistor of correspondence.When the resistance equalizing circuit controlling certain battery module connected by microcontroller through electronic switch array, microcontroller controls shutoff and the conducting of each field effect transistor in this battery module selectively, when certain field effect transistor conducting, the cell of its correspondence is in parallel with its discharge resistance.
Described electric capacity equalizing circuit comprises balanced electric capacity and switch arrays, and in each electric capacity equalizing circuit, the number of balanced electric capacity is m-1, and the switch number of switch arrays is m, i.e. the switch of the corresponding switch arrays of each cell.Each switch of switch arrays all has a fixed contact and 2 movable contacts, and the fixed contact of each switch connects one end of each balanced electric capacity respectively, 2 ends of 2 corresponding cells of movable contacts difference of each switch.When microcontroller connects the electric capacity equalizing circuit of certain battery module through electronic switch array, in this battery module of microprocessor controls, in switch arrays, the fixed contact of each switch connects different movable contacts in turn, and the balanced electric capacity that each Switch Controller is answered is in parallel in turn with adjacent two cells.
The microcontroller of native system connects warning device and/or display unit.
The balanced management method of the above-mentioned electric automobile power battery balanced management system of the present invention's design, microcontroller obtains battery pack nominal parameter by field control technology bus from battery management system: monomer number m in battery pack rated capacity, cell rated voltage v, battery pack rated voltage U, battery module number M and each battery module;
Microprocessor, according to receiving battery relevant parameter from battery management system above, according to the relation of electric vehicle motion performance and balanced intensity, in conjunction with the operating state of battery pack, determines the occurrence of the controling parameters of following battery pack as follows:
Monomer battery voltage higher limit v the upper limitfor 115% ~ 125% of cell rated voltage,
Monomer battery voltage lower limit v lower limitfor 80% ~ 90% of cell rated voltage,
The lower limit SOC of battery pack dump energy lower limitfor 10% ~ 20% of battery pack specified electric quantity,
The higher limit ε of cell voltage decentralization under charged state cHbe 6 ~ 9%,
The higher limit ε of cell voltage decentralization under discharge condition dHbe 4 ~ 6%,
The higher limit ε of the cell voltage decentralization under static condition sHbe 2 ~ 4%,
The lower limit Δ v of the monomer battery voltage maximum deviation in each battery module lower limitbe 30 ~ 50(mv),
The lower limit Δ U of maximum voltage difference between battery module lower limitbe 0.4 ~ 0.8(V),
The lower limit Δ I of battery pack current change lower limitfor-20 ~-10(A);
Equalizing coefficient n is directly proportional to battery rated capacity, when battery rated capacity is XAH, then gets n=X.
Concrete steps are as follows:
I, microcontroller calculates battery voltage decentralization ε
Microcontroller obtains battery pack by field control technology bus from battery management system and respectively runs the currency voltage V of variable, electric current I, the voltage of each cell and battery pack dump energy soco
Calculate the maximum deviation Δ U of the voltage between battery module;
Calculate monomer battery voltage maximum deviation Δ v in each battery module j, j is battery module numbering;
Calculate the mean value of monomer battery voltage
Calculate the maximum v of monomer battery voltage in battery pack mar;
Calculate the minimum value v of monomer battery voltage in battery pack min;
Calculate present battery group voltage decentralization ϵ = Σ i = 1 Mm ( v i - v ‾ ) 2 Mm - 1 ,
In formula: v ifor the voltage of cell i, for the mean value of all monomer battery voltages, Mm is total number of this power battery pack cell.
As ε < 2%, represent that consistency of battery pack is fine, without the need to equalization operation; Repeat this step I, the voltage decentralization ε that monitoring power battery pack is current.
II, microcontroller calculates balanced times N
Microcontroller calculates balanced times N according to the result of step I
N=(v max-v min) × ε × n, in formula, n is equalizing coefficient.
III, microcontroller selects equalization operation according to battery pack operating state
As battery current I > 0, be charged state, proceed to step IV;
As battery current I=0, be static condition, proceed to step V;
As battery current I < 0, be discharge condition, proceed to step VI.
IV, the equalization operation of charged state
In charging process, equalization operation is under the prerequisite preventing cell from overcharging, as far as possible, battery capacity is maximized on the one hand, is on the other hand under the prerequisite improving equalization efficiency, shortens the charging interval as far as possible.In charging process, change in voltage is obvious, and the voltage fluctuation that causes of charging is wanted and the unbalanced differentiation of voltage between module or monomer.In order to shorten the charging interval as far as possible, the criterion that equalization operation starts suitably reduces.
If IV-1 v max> v the upper limit, microcontroller prompting overcharges, and gives the alarm, and suspends charging; Otherwise proceed to step IV-2;
If IV-2 ε > ε cHand SOC>=SOC lower limit/ 2 enter step IV-3, otherwise return step I;
IV-3, open coaxial Multiple coil DC-DC converter, carry out the energy trasfer between battery module, the voltage difference automatic equalization of intermodule; To Δ U < Δ U lower limit, enter step IV-4;
IV-4, coaxial Multiple coil DC-DC converter is closed; By the inclined extent of the monomer battery voltage of each battery module, the switching of each switch in electronic switch array, the balanced electric capacity that each Switch Controller is answered is in parallel in turn with adjacent two cells, and energy flows between neighboring unit cell.By the electric capacity equalizing circuit of each battery module, carry out the equalization operation between cell in each battery module, balanced number of times is the N of step II gained, afterwards, closes the electric capacity equalizing circuit of each battery module; Proceed to step IV-5;
IV-5, the resistance equalizing circuit of each battery module is connected with electronic switch array, if the voltage difference between the cell in each battery module is all less than or equal to Δ v lower limit, return step I;
If the voltage difference in certain battery module between cell is greater than Δ v lower limit, the field effect transistor conducting that the cell that in this battery module of microprocessor controls, voltage is the highest is corresponding, the voltage difference between the cell that voltage is minimum to this monomer battery voltage and this battery module is less than Δ v lower limit, the field effect transistor that this cell of microprocessor controls is corresponding turns off, and then repeats judgement above and operation, and the voltage difference to each battery module between cell is less than or equal to Δ v lower limit, return step I.
V, the equalization operation of process is left standstill
In battery standing process, self-discharge of battery can cause the inconsistency of battery.Although battery self discharge rate is very little, along with battery charging and discharging number of times increases, the self-discharge rate of each cell there will be difference, when time of repose is longer, may occurs that certain cell is crossed and put, so also need balanced management under static condition.In addition, leave standstill the equalization problem solving battery in process, also indirectly decrease the pressure of charge and discharge process balanced management.In the process of leaving standstill, monomer voltage change is less, and equalizing criterions needs corresponding raising.
If V-1 v min< v lower limit, pointed out and put, gave the alarm, prompting charging; Otherwise proceed to step V-2;
If V-2 ε > ε sHand SOC>=SOC lower limit/ 2 enter step V-3, otherwise return step I;
V-3, open coaxial Multiple coil DC-DC converter, the energy between battery module carries out automatic equalization, to Δ U < Δ U lower limit, proceed to step V-4;
V-4, coaxial Multiple coil DC-DC converter is closed, by the inclined extent of each capacitance module monomer battery voltage, the switching of each switch in electronic switch array, the balanced electric capacity that each Switch Controller is answered is in parallel in turn with adjacent two cells, and energy flows between neighboring unit cell.By the electric capacity equalizing circuit of each battery module, carry out the equalization operation between cell in each battery module, balanced number of times is the N of step II gained, afterwards, closes the electric capacity equalizing circuit of each battery module; Proceed to step V-5;
V-5, the resistance equalizing circuit of each battery module is connected with electronic switch array, if the voltage difference between the cell in each battery module is all less than or equal to Δ v lower limit, return step I;
If the voltage difference in certain battery module between cell is greater than Δ v lower limit, the field effect transistor conducting that the cell that in this battery module of microprocessor controls, voltage is the highest is corresponding, the voltage difference between the cell that voltage is minimum to this monomer battery voltage and this battery module is less than Δ v lower limit, the field effect transistor that this cell of microprocessor controls is corresponding turns off, and then repeats judgement above and operation, and the voltage difference to each battery module between each cell is less than or equal to Δ v lower limit, return step I.
VI, the equalization operation of discharge process
Because equalization operation can affect to some extent on the exercise performance of electric automobile, in discharge process, first balanced management should be noted that and is ensureing under the prerequisite that cell is only put, reduce equalization operation number of times and do not use dissipativeness equalizing circuit, reducing the dissipation of the energy content of battery.
If VI-1 v min< v lower limit, pointed out and put, gave the alarm, prompting charging; Otherwise proceed to step VI-2;
VI-2, when electric motor car is at the uniform velocity transport condition, if ε > 2 is ε dHand SOC>=2SOC lower limitenter step VI-3, otherwise return step I;
When electric motor car is the state of giving it the gun, and because acceleration performance affects comparatively large by cell voltage decentralization, improves equalization operation standard, if and SOC>=2SOC lower limit, enter step VI-3, otherwise return step I;
When electric motor car is Reduced Speed Now state; If for the situation of bringing to a halt, suspend equalization operation, return step I; Otherwise be common Reduced Speed Now, if ε>=2 ε dHand SOC>=2SOC lower limit, enter step VI-3, otherwise return step I;
VI-3, open coaxial Multiple coil DC-DC converter, the energy between battery module carries out automatic equalization, to Δ U < Δ U lower limit, proceed to step VI-4;
VI-4, coaxial Multiple coil DC-DC converter is closed; By the inclined extent of each capacitance module monomer battery voltage, the switching of each switch in electronic switch array, the balanced electric capacity that each Switch Controller is answered is in parallel in turn with adjacent two cells, and energy flows between neighboring unit cell.By the electric capacity equalizing circuit of each battery module, in each battery module, carry out the equalization operation between cell, balanced number of times is the N of step II gained, afterwards, to calculate in each module maximum voltage difference Δ v between cell, as Δ v > Δ v lower limit, re-start the equalization operation of electric capacity equalizing circuit; Otherwise, close the electric capacity equalizing circuit of each battery module, return step I.
Cell is as ε < 2%, and represent that consistency of battery pack is fine, without the need to equalization operation, microcontroller sends signal to display unit, display unit display battery voltage decentralization ε < 2%.
When certain monomer battery voltage occurs too high or too low, or when battery pack occurs overcurrent, overvoltage, overcharges and crosses the situation such as to put for the moment, microcontroller transmits a signal to warning device, warning device action sound and/or light warning.During appearance alarm condition, display unit shows relative alarm information simultaneously.
Microcontroller is by the electric discharge of battery pack, charging and standing specific works state, and battery pack balancing situation and battery pack dump energy are sent to display unit display.
Microcontroller, by judging the low and high level that voltage acquisition comparison circuit outputs signal, control impuls driver element, the duty ratio of the pulse width modulated wave regulating it to export, exports and input voltage ratio to adjust coaxial Multiple coil DC-DC converter.When opening coaxial Multiple coil DC-DC converter, microcontroller leads to the power switch unit connecing transformer primary side input through pulse driver unit guide, during this power switch unit conducting, the rectifier diode that each secondary output of coaxial Multiple coil DC-DC converter transformer connects all ends, now each filter capacitor powers to corresponding power battery module, transformer primary side is equivalent to a pure inductance, stores the energy obtained by power battery pack.Microcontroller turns off the power switch unit of connection transformer former limit input, the power switch unit conducting that each secondary output connects, and the energy transferring that former limit stores, to secondary, provides electric current to each battery module, charges to filter capacitor simultaneously.Microcontroller receiver voltage gathers the output signal of comparison circuit, and the power switch unit connect by controlling former limit turns off and ON time, and it is M/mono-that former limit inputs that secondary is exported, and is namely the mean value of voltage between battery module.
Between battery module, voltage-regulation process is as follows:
If a jth battery module voltages is U in M battery module j, j=1,2 ... M, in the control signal of microcontroller, pulse width modulated wave duty ratio is δ, and transformer each secondary number of turn is identical, and former and deputy limit turn ratio is N1:N2.U 0for the average voltage of each battery module of battery pack, R jrepresent the internal resistance of a jth battery module, Δ U jrepresent voltage and the battery module average voltage U of a jth battery module 0deviation, Δ U j=U j– U 0.I jrepresent a jth battery module electric current, E jafter representing coaxial Multiple coil DC-DC converter inversion dividing potential drop, a jth secondary is added in a jth battery module both end voltage.
The voltage of a jth battery module is U j=U 0+ Δ U j, U m=U 0one Δ U m;
Then: E j = M &times; N 2 N 1 &times; &delta; &times; U 0
When time, E j=U 0, E m=U 0, suppose battery module 1 and battery module 2 voltage subaverage, then battery module 1 and battery module 2 have charging current, and all the other modules are all in electric discharge.The discharging current Ij that calculating can obtain the battery module of j=3 ~ M is:
I j = - 1 N [ &Delta; U 1 R 1 ( 1 - &Delta; U 1 U 0 ) + &Delta; U 2 R 2 ( 1 - &Delta; U 2 U 0 ) ] - - - ( 3 )
Euqalizing current is:
I 1 = &Delta; U 1 R 1 - I j - - - ( 4 )
I 2 = &Delta; U 2 R 2 - I j - - - ( 5 )
From formula (4) and (5), flow through the euqalizing current I of each battery module 1, I 2with the voltage of this battery module and the poor Δ U of each battery module average voltage jlinear, the Δ U of certain battery module jlarger, the euqalizing current flowing through this module is larger.Therefore multi output DC-DC converter can according to the energy of the inconsistent degree automatic equalization battery module of each battery module voltages.
Connect certain electric capacity equalizing circuit when carrying out equalization operation, the fixed contact of each switch of switch arrays of microprocessor controls electric capacity equalizing circuit connects its movable contact successively, two cells that the switching of switch makes each balanced electric capacity be adjacent are in parallel in turn, if the voltage of balanced electric capacity is greater than the voltage of cell in parallel process, balanced electric capacity charges to cell, otherwise cell is to balanced capacitor charging; By the balanced times N of step II, repeat N operation, by each balanced electric capacity, the energy of the cell that energy is high flows to the cell that energy is low, realizes the equilibrium between cell in same battery module.
When the resistance equalizing circuit that electronic switch array connects certain battery module carries out equalization operation, the conducting of this resistance equalizing circuit field effect transistor of microprocessor controls and shutoff, the voltage difference between the cell in this battery module is greater than Δ v lower limittime, the field effect transistor that the cell that in this battery module of microcontroller conducting, voltage is the highest is corresponding, the discharge resistance of this cell and its correspondence is in parallel, by the electric discharge of this discharge resistance, reduce this monomer battery voltage, the voltage difference that the voltage to this cell is down to the cell minimum with voltage in this battery module is less than or equal to Δ v lower limittime, microcontroller turns off field effect transistor corresponding to this cell, terminates the electric discharge to this cell; If the voltage difference between the cell now in this battery module is still greater than Δ v lower limit, more as mentioned above equalization discharge is carried out to the cell that in this battery module, now voltage is the highest; As above operate successively, the voltage difference to this battery module between each cell is less than or equal to Δ v lower limittime, microcontroller turns off resistance equalizing circuit corresponding to this battery module by electronic switch array.
Compared with prior art, the advantage of electric automobile power battery balanced management system of the present invention and balanced management method is: 1, comprehensive coaxial Multiple coil DC-DC converter, electric capacity equalizing circuit and resistance equalizing circuit, carry out the equilibrium of top layer (between battery module) and bottom (between the monomer in module) respectively, multiple equalizing circuit is had complementary advantages, not only increase balancing speed, also significantly increase equalization efficiency, also avoid the adverse effect that single equilibrium mode may be brought simultaneously; 2, select battery voltage decentralization, battery pack dump energy and monomer voltage as the reference quantity of equalization operation, pointedly equalization operation is carried out to cell, the inconsistency of remarkable reduction battery, it also avoid cell simultaneously and occurs overcharging or crossing the phenomenon of putting; 3, according to the different operating state of electrokinetic cell, adjustment equalizing criterions, adopt different equalization operation criterions, particularly when battery discharge, consider the different equalization operation of electric automobile at the uniform velocity, when slowing down and give it the gun, adapt to battery operating state complicated and changeable, improve battery pack balancing efficiency, increase battery pack useful life; 4, microcontroller connects warning device and display unit, and display unit shows each relevant parameter state of battery pack in real time, and the situations such as warning device is put overcharging, crossing in time, overcurrent, overvoltage are reported to the police, to protect battery pack.
Accompanying drawing explanation
Fig. 1 is the overall structure schematic diagram of this electric automobile power battery balanced management system embodiment;
Fig. 2 is the structural representation of coaxial Multiple coil DC-DC converter in Fig. 1;
Fig. 3 is the connection diagram of battery module 1 and its resistance equalizing circuit 1 in Fig. 1;
Fig. 4 is the connection diagram of battery module 1 and its electric capacity equalizing circuit 1 in Fig. 1;
Fig. 5 is the general flow chart of the management method embodiment of this electric automobile power battery balanced management system;
Fig. 6 is the equalization operation flow chart under the charged state of the embodiment of the present invention;
Fig. 7 is the equalization operation flow chart under the static condition of the embodiment of the present invention;
Fig. 8 is the equalization operation flow chart under the discharge condition of the embodiment of the present invention.
Embodiment
Below in conjunction with the drawings and specific embodiments, electric automobile power battery balanced management system embodiment is described in further detail to the present invention
This electric automobile power battery balanced management system embodiment overall structure as shown in Figure 1, comprise microcontroller, this routine battery balanced management system is connected with battery management system, and battery management system is furnished with the testing circuit obtaining the current operational factor of power battery pack.Cell in this routine electric automobile power battery group is 12 altogether, is divided into 3 identical battery modules, comprises 4 cells, i.e. B11 ~ B14, B21 ~ B24, B31 ~ B34, B41 ~ B44 in each battery module by series sequence.Each battery module connects resistance equalizing circuit corresponding with it and electric capacity equalizing circuit respectively, and coaxial Multiple coil DC-DC converter is connected with each battery module.
Described microcontroller is connected with battery management system through field control technology bus, the signal output part of microcontroller connects the control end of each electric capacity equalizing circuit and resistance equalizing circuit respectively through electronic switch array, namely microcontroller can connect through electronic switch array or cut out the electric capacity equalizing circuit corresponding with certain battery module or resistance equalizing circuit.One road signal C of microcontroller pB0access pulse driver unit, the output signal C of the pulse-width signal PWM that pulse driver unit exports and microcontroller pB1, C pB2, C pB3connect each control end of coaxial Multiple coil DC-DC converter.
The structure of described coaxial Multiple coil DC-DC converter as shown in Figure 2, comprises transformer T1, power switch unit, rectifier diode and filter capacitor, and converter is inverse-excitation type structure, and the number of turn of 3 secondary is identical; The input one end on former limit is connected with the positive pole of battery pack, the other end on former limit is connected to ground through a power switch unit Q1, every road secondary output port is connected the two ends of filter capacitor respectively with a rectifier diode (D2, D3, D4) through a power switch unit (Q2, Q3, Q4), filter capacitor and corresponding battery module parallel connection of each secondary.This example is for reaching good filter effect, each filter capacitor is small one and large one two Capacitance parallel connections, and as shown in Figure 2, C1 and C4 parallel connection is the filter capacitor of first via secondary, C2 and C5 parallel connection is the filter capacitor of the second road secondary, C3 and C6 parallel connection is the filter capacitor of the 3rd road secondary.The control signal C of microcontroller pB0connect pulse driver unit U1, control the duty ratio of the pulse-width signal PWM that it exports, pulse driver unit signal output part connects the power switch unit Q1 that former limit connects, the signal C of microcontroller pB1, C pB2, C pB3connect power switch unit Q2, Q3, Q4 of each secondary, control their conducting and shutoff.
The former limit input voltage of the coaxial Multiple coil DC-DC converter of this example is connected with end of oppisite phase with the in-phase end of voltage acquisition comparison circuit U1 respectively with first via secondary output voltage, the output P of voltage acquisition comparison circuit U1 lMbe connected with microcontroller.Microcontroller is by the output signal P of voltage acquisition comparison circuit U1 lMjudge the relation of coaxial Multiple coil DC-DC converter input voltage and output voltage, and then regulate each control signal, the input of coaxial Multiple coil DC-DC converter and each secondary are exported in strict linear relationship.
The structure of the resistance equalizing circuit 1 of this routine battery module 1 as shown in Figure 3, comprises a 4 discharge resistance R11 ~ R14 and 4 field effect transistor Q11 ~ Q14, and each cell connects the discharge resistance of its correspondence through the field effect transistor of correspondence.Field effect transistor Q11 and discharge resistance R11 as corresponding in cell B11.When microcontroller connects the resistance equalizing circuit of the first battery module through electronic switch array, the shutoff conducting of the field effect transistor that each cell of microprocessor controls is corresponding.When microcontroller sends a high level to certain field effect transistor, this field effect transistor conducting, the cell of its correspondence is in parallel with its discharge resistance; When microcontroller sends a low level to certain field effect transistor, then this field effect transistor turns off, and the cell of its correspondence and its discharge resistance disconnect.The structure of the resistance equalizing circuit of other battery module is identical therewith.
The structure of the corresponding electric capacity equalizing circuit 1 of this routine battery module 1 as shown in Figure 4, comprises 3 balanced electric capacity C11 ~ C13 and the electronic switch array having 4 switch S 11 ~ S14, i.e. the switch of the corresponding switch arrays of each cell.Switch S 11 ~ S14 all has a fixed contact and 2 movable contacts, and the fixed contact of 4 switches connects one end of 3 balanced electric capacity C11 ~ C13 respectively, 2 ends of 2 corresponding 1 cells of movable contacts difference of each switch.As shown in Figure 4, the fixed contact of switch S 11 is connected to the outer end of balanced electric capacity C11, and its 2 movable contacts connect the two ends of cell B11 respectively.By that analogy.When each switch S 11 ~ S14 fixed contact of switch arrays is all connected with the movable contact in left side, B11 and C11 is in parallel, B12 and C12 is in parallel, B13 and C13 is in parallel, when each switch S 11 to S14 fixed contact of switch arrays is all connected with the movable contact on right side, B12 and C11 is in parallel, B13 and C12 is in parallel, B14 and C13 is in parallel.The structure of the electric capacity equalizing circuit of other battery module is identical therewith.
The microcontroller of this example connects warning device and display unit.
The balanced management embodiment of the method for electric automobile power battery balanced management system
This balanced management embodiment of the method is the balanced management method adopting above-mentioned electric automobile power battery balanced management system embodiment, microcontroller obtains this routine battery pack nominal parameter by field control technology bus from battery management system: cell rated voltage v=3.2(v), battery pack rated voltage U=38.4(v), battery pack rated capacity 30AH, cell sum 12, be divided into three battery modules.
Microprocessor is according to receiving battery relevant parameter from battery management system above, and this example determines the occurrence of the controling parameters of following battery pack as follows:
Monomer battery voltage higher limit v the upper limitbe 3.85 (V),
Monomer battery voltage lower limit v lower limitbe 2.80 (V),
The lower limit soc of battery pack dump energy lower limitfor 20% of battery pack specified electric quantity,
The higher limit ε of cell voltage decentralization under charged state cHbe 8%,
The higher limit ε of cell voltage decentralization under discharge condition dHbe 5%,
The higher limit ε of the cell voltage decentralization under static condition sHbe 3%,
The lower limit Δ U of maximum voltage difference between battery module lower limitbe 0.8 (V),
The lower limit Δ υ of maximum voltage deviation between cell in each battery module lower limitfor 30mv,
The lower limit Δ I of battery pack current change lower limitfor-10 (A);
Equalizing coefficient n is directly proportional to battery rated capacity, this routine n=30.
When certain monomer battery voltage occurs too high or too low, or when battery pack occurs overcurrent, overvoltage, overcharges and crosses the situation such as to put for the moment, microcontroller transmits a signal to warning device, warning device action sound and light warning.During appearance alarm condition, display unit shows relative alarm information simultaneously.
Microcontroller is by the electric discharge of battery pack, charging and standing specific works state, and battery pack balancing situation and remaining capacity SOC are sent to display unit display.
As shown in Figure 5, concrete steps are as follows for this routine balancing procedure:
I, microcontroller calculates battery voltage decentralization ε
Microcontroller obtains battery pack by field control technology bus from battery management system and respectively runs the currency voltage V of variable, electric current I, each monomer voltage and battery pack dump energy soc;
Calculate the maximum deviation Δ U of the voltage between battery module;
Calculate the voltage maximum deviation Δ v in each battery module between cell 1, Δ v 2, Δ v 3;
Calculate the mean value of monomer battery voltage
Calculate the maximum v of monomer voltage in battery pack max;
Calculate the minimum value v of monomer voltage in battery pack min;
Calculate present battery group voltage decentralization, &epsiv; = &Sigma; i = 1 Mm ( v i - v &OverBar; ) 2 Mm - 1 ,
In formula: v ifor the voltage of cell i, for the mean value of all monomer battery voltages, Mm is total number of this power battery pack cell.
As ε < 2%, represent that consistency of battery pack is fine, without the need to equalization operation; Repeat this step I, the voltage decentralization ε that monitoring power battery pack is current.Microcontroller sends signal to display unit, display unit display battery voltage decentralization ε < 2%.
II, microcontroller calculates balanced times N
Microcontroller calculates balanced times N according to the result of step I
N=(v max-v min) × ε × n, in formula, n=30 is equalizing coefficient.
III, microcontroller selects equalization operation according to battery pack operating state
As battery current I > 0, be charged state, proceed to step IV;
As battery current I=0, be static condition, proceed to step V;
As battery current I < 0, be discharge condition, proceed to step VI.
IV, the equalization operation of charged state
This flow chart of steps as shown in Figure 6.
If IV-1 v max> v the upper limit, microcontroller prompting overcharges, and gives the alarm, and suspends charging; Otherwise proceed to step IV-2;
If IV-2 ε > ε cHand SOC>=SOC lower limit/ 2 enter step IV-3, otherwise return step I;
IV-3, Δ U > U lower limitopen coaxial Multiple coil DC-DC converter, carry out the energy trasfer between battery module, the voltage difference automatic equalization of intermodule; To Δ U≤U lower limit, enter step IV-4;
IV-4, coaxial Multiple coil DC-DC converter is closed; By the inclined extent of the monomer battery voltage of each battery module, the switching of each switch in electronic switch array, the balanced electric capacity that each Switch Controller is answered is in parallel in turn with adjacent two cells, and energy flows between neighboring unit cell.By the electric capacity equalizing circuit of each battery module, in each battery module, carry out equalization operation between cell, balanced number of times is the N of step II gained; Afterwards, close the electric capacity equalizing circuit of each battery module, proceed to step IV-5;
IV-5, the resistance equalizing circuit of each battery module is connected with electronic switch array;
If the voltage difference between the cell in each battery module is all less than or equal to Δ v lower limit(this example is 50mv), returns step I;
If the voltage difference in certain battery module between cell is greater than Δ v lower limit, the field effect transistor conducting that the cell that in this battery module of microprocessor controls, voltage is the highest is corresponding, the voltage difference between the cell that voltage is minimum to this monomer battery voltage and this battery module is less than Δ v lower limit, the field effect transistor that this cell of microprocessor controls is corresponding turns off, and then repeats judgement above and operation, and the voltage difference to each battery module between cell is less than or equal to Δ v lower limit, epicycle equalization operation terminates, and returns step I.
V, the equalization operation of process is left standstill
This flow chart of steps as shown in Figure 7.
If V-1 v min< v lower limit, pointed out and put, gave the alarm, prompting charging; Otherwise proceed to step V-2;
If V-2 ε > ε sHand SOC>=SOC lower limit/ 2 enter step V-3, otherwise return step I;
V-3, open coaxial Multiple coil DC-DC converter, the energy between battery module carries out automatic equalization, to Δ U < Δ U lower limit, proceed to step V-4;
V-4, coaxial Multiple coil DC-DC converter is closed, by the inclined extent of each capacitance module monomer battery voltage, the switching of each switch in electronic switch array, the balanced electric capacity that each Switch Controller is answered is in parallel in turn with adjacent two cells, and energy flows between neighboring unit cell.By the electric capacity equalizing circuit of each battery module, in each battery module, carry out equalization operation between cell, balanced number of times is the N of step II gained; Afterwards, close the electric capacity equalizing circuit of each battery module, proceed to step V-5;
V-5, the resistance equalizing circuit of each battery module is connected with electronic switch array;
If the voltage difference between the monomer in each battery module is all less than or equal to Δ v lower limit, return step I;
If the voltage difference in certain battery module between cell is greater than Δ v lower limit, the field effect transistor conducting that the cell that in this battery module of microprocessor controls, voltage is the highest is corresponding, the voltage difference to this monomer battery voltage and this battery module between the minimum cell of voltage is less than Δ v lower limit, the field effect transistor that this cell of microprocessor controls is corresponding turns off, and then repeats judgement above and operation, and the voltage difference to each battery module between cell is less than or equal to Δ v lower limit, epicycle equalization operation terminates, and returns step I.
VI, the equalization operation of discharge process
This flow chart of steps as shown in Figure 8.
If VI-1 v min< v lower limit, pointed out and put, gave the alarm, prompting charging; Otherwise proceed to step VI-2;
VI-2, when electric motor car is at the uniform velocity transport condition, if ε > is ε dHand SOC>=2SOC lower limit, enter step VI-3, otherwise return step I;
When electric motor car is the state of giving it the gun, if ε > is ε dH/ 2 and SOC>=2SOC lower limit, enter step VI-3, otherwise return step I;
When electric motor car is Reduced Speed Now state, if for the situation of bringing to a halt, suspend equalization operation, return step I; Otherwise be common Reduced Speed Now, if ε > is ε dHand SOC>=2SOC lower limit, enter step VI-3, otherwise return step I;
VI-3, open coaxial Multiple coil DC-DC converter, the energy between battery module carries out automatic equalization, to Δ U < Δ U lower limit, proceed to step VI-4;
VI-4, coaxial Multiple coil DC-DC converter is closed; By the inclined extent of each capacitance module monomer battery voltage, the switching of each switch in electronic switch array, the balanced electric capacity that each Switch Controller is answered is in parallel in turn with adjacent two cells, and energy flows between neighboring unit cell.By the electric capacity equalizing circuit of each battery module, carry out the equalization operation between cell in each battery module, balanced number of times is the N of step II gained; Afterwards, maximum voltage difference Δ v between cell is calculated in each battery module, if Δ v > Δ v lower limit, re-start the equalization operation of electric capacity equalizing circuit; Otherwise, close the electric capacity equalizing circuit of each battery module, return step I.
When opening coaxial Multiple coil DC-DC converter, microcontroller leads to the power switch unit Q1 of connection transformer T1 former limit input through pulse driver unit guide, during the Q1 conducting of this power switch unit, each rectifier diode D2, D3, D4 that coaxial Multiple coil DC-DC converter transformer T1 secondary output connects end, now each filter capacitor C1 and C4, C2 and C5, C3 and C6 power to corresponding power battery module, and the former limit of transformer T1 stores the energy obtained by power battery pack.Microcontroller turns off the power switch unit Q1 of connection transformer T1 former limit input, the power switch unit Q2 to Q4 that connects of each secondary output of conducting again, the energy transferring that former limit stores, to secondary, provides electric current to each battery module, charges to each filter capacitor simultaneously.Multi output DC-DC converter is according to the energy of each battery module of inconsistent degree automatic equalization of voltage between each battery module.
As shown in Figure 4, when microcontroller connects the electric capacity equalizing circuit of battery module 1 through electronic switch array, in the switch arrays of the electric capacity equalizing circuit 1 of this battery module 1 correspondence of microprocessor controls, movable contact on the left of it first connected by the fixed contact of each switch S 11 ~ S14, cell B11, B12 and B13 respectively with balanced electric capacity C11, C12 and C13 is in parallel, if the voltage of the balanced electric capacity of parallel process is greater than the voltage of cell, balanced electric capacity charges to cell, otherwise, cell is to balanced capacitor charging, until B11 and C11, B12 and C12, the voltage of B13 and C13 is equal, the switch S 11 of microcontroller again in control switch array, S12, S13 connect movable contact on the right side of it, and now B12 and C11, B13 and C12, B14 and C13 are in parallel, until the voltage of both sides in parallel is equal, by the balanced number of times M of step II, repeatedly carry out N operation, realize the flowing of energy between cell by balanced electric capacity and reach balanced.
As shown in Figure 3, when microcontroller carries out equalization operation through the resistance equalizing circuit 1 of electronic switch array connection battery module 1, the conducting of this resistance equalizing circuit field effect transistor of microprocessor controls and shutoff, when the voltage difference of this example between cell is greater than 30mv, the field effect transistor that the cell that in this battery module of microcontroller conducting, voltage is the highest is corresponding, the discharge resistance of this cell and its correspondence is in parallel, this cell is discharged by this discharge resistance, reduce this monomer battery voltage, when the voltage difference that voltage to this cell is down to the cell minimum with voltage in this battery module is less than or equal to 30mv, microcontroller turns off field effect transistor corresponding to this cell, terminate the electric discharge to this cell, if the voltage difference between the cell now in this battery module is still greater than 30mv, then carries out equalization discharge as mentioned above to the cell that in this battery module, now voltage is the highest, as above operate successively, when the voltage difference to this battery module between each cell is less than or equal to 30mv, microcontroller turns off the electronic switch of resistance equalizing circuit corresponding to this battery module.
Adopt the balanced management method of this routine electric automobile power battery balanced management system at 25 DEG C, 12 LiFePO4 cells are when initial condition, cell maximum voltage difference is 200mV, after the equalization operation of this method, the maximum difference of monomer battery voltage is only 30mV, battery decentralization is less than 2%, temperature rise is less than 10 DEG C, and battery pack extends one times useful life.And do not adopt this balanced management system to carry out balanced same battery group, within the same cycle of operation, the maximum absolute difference of monomer battery voltage is up to 200mV.
Above-described embodiment, be only the specific case further described object of the present invention, technical scheme and beneficial effect, the present invention is not defined in this.All make within scope of disclosure of the present invention any amendment, equivalent replacement, improvement etc., be all included within protection scope of the present invention.

Claims (5)

1. the balanced management method of electric automobile power battery balanced management system, described electric automobile power battery balanced management system, comprise microcontroller, microcontroller connects battery management system through field control technology bus, and battery management system is furnished with the testing circuit obtaining power battery pack current operating parameter;
Cell in electric automobile power battery group is divided into the individual identical battery module of M by series sequence, and 2≤M≤40, comprise m cell 2≤m≤8 in each battery module; Each battery module connects resistance equalizing circuit corresponding with it and electric capacity equalizing circuit respectively, and coaxial Multiple coil DC-DC converter is connected with each battery module;
Described microcontroller obtains nominal parameter and the current operating parameter of power battery pack by battery management system, and stores; The signal output part of microcontroller connects the control end of each electric capacity equalizing circuit and resistance equalizing circuit respectively through electronic switch array, one road signal access pulse driver unit of microcontroller, the pulse-width signal that pulse driver unit exports is connected each control end of coaxial Multiple coil DC-DC converter with the control signal that microcontroller exports;
Described coaxial Multiple coil DC-DC converter comprises transformer, power switch unit, rectifier diode and filter capacitor, and converter is inverse-excitation type structure; The number of transformer secondary is that the number of turn of the number M of battery module, a M secondary is identical; The input one end on former limit connects battery anode, the other end on former limit is connected to ground through a power switch unit, every road secondary output port is connected the two ends of filter capacitor respectively with a rectifier diode through a power switch unit, filter capacitor and corresponding battery module parallel connection of each secondary, the control signal of microcontroller connects pulse driver unit, and pulse driver unit signal output part connects the power switch unit on former limit; The signal end of microcontroller also connects the power switch unit of each secondary connection; The former limit input voltage of coaxial Multiple coil DC-DC converter is connected with end of oppisite phase with the in-phase end of voltage acquisition comparison circuit respectively with a certain road secondary output voltage, and the output of voltage acquisition comparison circuit is connected with microcontroller;
Described resistance equalizing circuit comprises discharge resistance and field effect transistor, described discharge resistance number and field effect transistor number equal cell number m in battery module, and in each resistance equalizing circuit, each cell connects the discharge resistance of its correspondence through the field effect transistor of correspondence; When microcontroller connects the resistance equalizing circuit of certain battery module through electronic switch array, when microcontroller is selected to control certain field effect transistor conducting, the cell of its correspondence is in parallel with its discharge resistance;
Described electric capacity equalizing circuit comprises balanced electric capacity and switch arrays, in each electric capacity equalizing circuit, the number of balanced electric capacity is m-1, the switch number of switch arrays is m, each switch of switch arrays all has a fixed contact and 2 movable contacts, the fixed contact of each switch connects one end of each balanced electric capacity respectively, 2 ends of 2 corresponding cells of movable contacts difference of each switch; When microcontroller connects the electric capacity equalizing circuit of certain battery module through electronic switch array, in this battery module of microprocessor controls, in switch arrays, the fixed contact of each switch connects different movable contacts successively, and two cells that the balanced electric capacity that each Switch Controller is answered is adjacent are in parallel in turn;
It is characterized in that:
Microcontroller obtains battery pack nominal parameter by field control technology bus from battery management system: cell number m in battery pack rated capacity, cell rated voltage v, battery pack rated voltage U, battery module number M and each battery module;
Microprocessor, according to the battery relevant parameter received from battery management system above, determines the occurrence of the controling parameters of following battery pack as follows:
Monomer battery voltage higher limit v the upper limitfor 115% ~ 125% of cell rated voltage,
Monomer battery voltage lower limit v lower limitfor 80% ~ 90% of cell rated voltage,
The lower limit SOC of battery pack dump energy lower limitfor 20% of battery pack specified electric quantity,
The higher limit ε of cell voltage decentralization under charged state cHbe 7% ~ 9%,
The higher limit ε of cell voltage decentralization under discharge condition dHbe 4% ~ 6%,
The higher limit ε of the cell voltage decentralization under static condition sHbe 2% ~ 4%,
The lower limit Δ U of maximum voltage difference between battery module lower limitfor 400mV ~ 800mV,
The lower limit Δ v of the monomer battery voltage maximum deviation in each battery module lower limitfor 30mV ~ 50mV,
The lower limit Δ I of battery pack current change lower limitfor-20A ~-10A;
Equalizing coefficient n is directly proportional to battery rated capacity, when battery rated capacity is XAH, then gets n=X;
Concrete steps are as follows:
I, microcontroller calculate battery voltage decentralization ε
Microcontroller obtains from battery management system currency voltage V, electric current I, the monomer battery voltage minimum value v that battery pack respectively runs variable by field control technology bus min, monomer battery voltage maximum v max, battery pack remaining capacity SOC;
Calculate the maximum deviation Δ U of the voltage between battery module;
Calculate monomer battery voltage maximum deviation Δ v in each battery module j, j is battery module numbering;
Calculate the mean value of monomer battery voltage
Calculate the maximum v of monomer battery voltage in battery pack max;
Calculate the minimum value v of monomer battery voltage in battery pack min;
Calculate present battery group voltage decentralization,
In formula: v ifor the voltage of cell i, for the mean value of all monomer battery voltages, Mm is total number of this power battery pack cell;
As ε < 2%, represent that consistency of battery pack is fine, without the need to equalization operation; Repeat this step I, the voltage decentralization ε that monitoring power battery pack is current;
II, microcontroller calculate balanced times N
Microcontroller calculates balanced times N according to the result of step I
N=(v max-v min) × ε × n, in formula, n is equalizing coefficient;
III, microcontroller select equalization operation according to battery pack operating state
As battery current I > 0, be charged state, proceed to step IV;
As battery current I=0, be static condition, proceed to step V;
As battery current T < 0, be discharge condition, proceed to step VI;
The equalization operation of IV, charged state
If IV-1 is v max> v the upper limit, microcontroller prompting overcharges, and gives the alarm, and suspends charging; Otherwise proceed to step IV-2;
If IV-2 ε > is ε cHand SOC>=SOC lower limit/ 2 enter step IV-3, otherwise return step I;
IV-3, open coaxial Multiple coil DC-DC converter, carry out the energy trasfer between battery module, the voltage difference automatic equalization of intermodule; To Δ U < Δ U lower limit, enter step IV-4;
IV-4, close coaxial Multiple coil DC-DC converter; By the inclined extent of each battery module monomer battery voltage, the switching of each switch in electronic switch array, the balanced electric capacity that each Switch Controller is answered is in parallel in turn with adjacent two cells, by the electric capacity equalizing circuit of each battery module, the equalization operation between cell is carried out in each battery module, balanced number of times is the N of Step II gained, afterwards, closes the electric capacity equalizing circuit of each battery module; Proceed to step IV-5;
IV-5, connect the resistance equalizing circuit of each battery module with electronic switch array; If the voltage difference in certain battery module between cell is greater than Δ v lower limit, the field effect transistor conducting that the cell that in this battery module of microprocessor controls, voltage is the highest is corresponding, the voltage difference between the cell that voltage is minimum to this monomer battery voltage and this battery module is less than Δ v lower limit, the field effect transistor that this cell of microprocessor controls is corresponding turns off, and then repeat judgement above and operation, the voltage difference to each battery module between cell is less than or equal to Δ v lower limit, epicycle equalization operation terminates, and returns step I;
The equalization operation of V, standing process
If V-1 is v min< v lower limit, pointed out and put, gave the alarm, prompting charging; Otherwise proceed to step V-2;
If V-2 ε > is ε sHand SOC>=SOC lower limit/ 2 enter step V-3, otherwise return step I;
V-3, open coaxial Multiple coil DC-DC converter, the energy between battery module carries out automatic equalization, to Δ U < Δ U lower limit, proceed to step V-4;
V-4, close coaxial Multiple coil DC-DC converter, by the inclined extent of the monomer battery voltage of each battery module, the switching of each switch in electronic switch array, the balanced electric capacity that each Switch Controller is answered is in parallel in turn with adjacent two cells, by the electric capacity equalizing circuit of each battery module, in each battery module, carry out the equalization operation between cell, balanced number of times is the N of Step II gained; Afterwards, close the electric capacity equalizing circuit of each battery module, proceed to step V-5;
V-5, connect the resistance equalizing circuit of each battery module with electronic switch array;
If the voltage difference in certain battery module between cell is greater than Δ v lower limit, the field effect transistor conducting that the cell that in this battery module of microprocessor controls, voltage is the highest is corresponding, the voltage difference between the cell that voltage is minimum to this monomer battery voltage and this battery module is less than Δ v lower limit, the field effect transistor that this cell of microprocessor controls is corresponding turns off, and then repeat judgement above and operation, the voltage difference to modules between cell is less than or equal to Δ v lower limit, epicycle equalization operation terminates, and returns step I;
The equalization operation of VI, discharge process
If VI-1 is v min< v lower limit, pointed out and put, gave the alarm, prompting charging; Otherwise proceed to step VI-2;
VI-2, when electric motor car is at the uniform velocity transport condition, if ε > is ε dHand SOC > 2SOC lower limitenter step VI-3, otherwise return step I;
When electric motor car is the state of giving it the gun, if ε > is ε dH/ 2 and SOC > 2SOC lower limit, enter step VI-3, otherwise return step I;
When electric motor car is Reduced Speed Now state, if for the situation of bringing to a halt, suspend equalization operation, return step I; Otherwise be common Reduced Speed Now, if ε > 2 is ε dHand SOC>=2SOC lower limit, enter step IV-3, otherwise return step I;
VI-3, open coaxial Multiple coil DC-DC converter, the energy between battery module carries out automatic equalization, to Δ U < Δ U lower limit, proceed to step VI-4;
VI-4, close coaxial Multiple coil DC-DC converter circuit, by the inclined extent of each battery module monomer battery voltage, the switching of each switch in electronic switch array, the balanced electric capacity that each Switch Controller is answered is in parallel in turn with adjacent two cells, by the electric capacity equalizing circuit of each battery module, in each battery module, carry out equalization operation between cell, balanced number of times is the N of Step II gained; Afterwards, maximum voltage difference Δ v between cell is calculated in each module, if Δ v > Δ v lower limit, re-start the equalization operation of electric capacity equalizing circuit; Otherwise, close the electric capacity equalizing circuit of each battery module, return step I.
2. the balanced management method of electric automobile power battery balanced management system according to claim 1, is characterized in that:
Described microcontroller connects warning device and display unit,
As ε < 2%, microcontroller sends signal to display unit, display unit display battery voltage decentralization ε < 2%;
When certain monomer battery voltage occurs too high or too low, or when battery pack there is overcurrent, overvoltage, overcharge and cross to one's heart's content condition a period of time, microcontroller transmits a signal to warning device, and warning device action sound and/or light are reported to the police, and display unit shows relative alarm information simultaneously;
Microcontroller is by the electric discharge of battery pack, charging and standing specific works state, and battery pack balancing situation and battery pack dump energy are sent to display unit display.
3. the balanced management method of electric automobile power battery balanced management system according to claim 1, is characterized in that:
Microcontroller is by judging the low and high level that voltage acquisition comparison circuit outputs signal, the duty ratio of the pulse width modulated wave that control impuls driver element regulates it to export; When coaxial Multiple coil DC-DC converter circuit connected by microcontroller, microcontroller leads to the power switch unit connecing transformer primary side input through pulse driver unit guide, during this power switch unit conducting, each rectifier diode that coaxial Multiple coil DC-DC converter transformer secondary output connects all ends, now each filter capacitor powers to corresponding power battery module, and transformer primary side stores the energy obtained by power battery pack; Microcontroller turns off the power switch unit of connection transformer former limit input, the power switch unit that each secondary output of conducting connects, the energy transferring that former limit stores is to secondary, there is provided electric current to each battery module, simultaneously to filter capacitor charging, the difference flowing through the euqalizing current of each battery module and the voltage of corresponding battery module and each battery module average voltage is linear; Microcontroller receiver voltage gathers the output signal of comparison circuit, by control power switch unit that former limit connects and secondary connect shutoff and the ON time of power switch unit, make secondary output voltage be M/mono-of former limit input voltage, namely secondary output voltage is the mean value of voltage between battery module.
4. the balanced management method of electric automobile power battery balanced management system according to claim 1, is characterized in that:
Connect certain electric capacity equalizing circuit when carrying out equalization operation, the fixed contact of each switch of switch arrays of microprocessor controls electric capacity equalizing circuit connects its movable contact successively, two cells that the switching of switch makes each balanced electric capacity be adjacent are in parallel in turn, if the voltage of balanced electric capacity is greater than the voltage of cell in parallel process, balanced electric capacity charges to cell, otherwise cell is to balanced capacitor charging; By the balanced times N of Step II, repeat N operation.
5. the balanced management method of electric automobile power battery balanced management system according to claim 1, is characterized in that:
When the resistance equalizing circuit that described microcontroller electronic switch array connects certain battery module carries out equalization operation, the conducting of this resistance equalizing circuit field effect transistor of microprocessor controls and shutoff, the voltage difference between the cell in this battery module is greater than Δ v lower limittime, the field effect transistor that the cell that in this battery module of microcontroller conducting, voltage is the highest is corresponding, the discharge resistance of this cell and its correspondence is in parallel, this cell is discharged by this discharge resistance, is reduced this monomer battery voltage, and the voltage difference that the voltage to this cell is down to the cell minimum with voltage in this battery module is less than or equal to Δ v lower limittime, microcontroller turns off field effect transistor corresponding to this cell, terminates the electric discharge to this cell; If the voltage difference between the cell now in this battery module is still greater than Δ v lower limit, more as mentioned above equalization discharge is carried out to the cell that in this battery module, now voltage is the highest; As above operate successively, the voltage difference to this battery module between each cell is less than or equal to Δ v lower limittime, microcontroller turns off resistance equalizing circuit corresponding to this battery module by electronic switch array.
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