CN109687548B - Supplementary electric formula of storage battery initiative balancing unit - Google Patents
Supplementary electric formula of storage battery initiative balancing unit Download PDFInfo
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- CN109687548B CN109687548B CN201811617879.9A CN201811617879A CN109687548B CN 109687548 B CN109687548 B CN 109687548B CN 201811617879 A CN201811617879 A CN 201811617879A CN 109687548 B CN109687548 B CN 109687548B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
- H02J7/0014—Circuits for equalisation of charge between batteries
- H02J7/0019—Circuits for equalisation of charge between batteries using switched or multiplexed charge circuits
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4207—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells for several batteries or cells simultaneously or sequentially
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
- H02J7/0014—Circuits for equalisation of charge between batteries
- H02J7/0016—Circuits for equalisation of charge between batteries using shunting, discharge or bypass circuits
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
- H01M2010/4271—Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
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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
Abstract
A supplementary power type active equalization device for a storage battery pack comprises at least one equalization function module, a DC/DC module, an active equalization power supply battery and an MCU (microprogrammed control unit), wherein the equalization function module comprises a bidirectional isolation switch array of a group of single batteries, an arbitration unit, an isolation charging module and an isolation measurement module. Each balancing function module can independently complete the active balancing of a group of single batteries under the coordination of the MCU and the active balancing power supply battery. The arbitration unit is responsible for arbitrating the switches corresponding to the equalized batteries in the bidirectional isolating switch array, the independent gating mechanism of the arbitration unit can avoid the risk of short circuit of the batteries from hardware, and the arbitration unit is also required to control the time division multiplexing of the isolating charging module and the isolating measurement module so as to prevent the charging module and the measurement module from influencing each other. The charging energy of the invention is from the battery pack, the accuracy and the safety of charging and measuring are ensured by the arbitration unit, and the expansion of the equalizing battery pack is realized by the multiplexing of a plurality of functional modules.
Description
Technical Field
The invention relates to the technical field of battery pack balance management, in particular to an active balance system of a supplementary electric storage battery pack.
Background
The storage battery is often used by connecting the storage battery in series to increase the voltage, but due to the influence of various different factors of different single batteries, characteristics of the single batteries are inconsistent. This inconsistency greatly affects the performance of the entire battery pack, and the "barrel effect" exhibited causes the entire battery pack to be affected. Sometimes, the service life and the use safety of the whole battery pack are even seriously influenced. The balance management technology dynamically adjusts the energy balance of each single battery in the battery pack by monitoring the state parameters of the single batteries in real time, and is a fundamental way for solving the problem of inconsistency. According to the equalization energy transfer mode, equalization management techniques can be divided into two main categories, namely passive equalization and active equalization. The active equalization has the characteristic of high precision, the charging type active equalization avoids the defects of energy waste and heating of the discharging type equalization, and the charging type active equalization has the advantages of energy conservation, environmental protection and safety.
Disclosure of Invention
The invention aims to provide a storage battery electricity supplementing type active balancing device, which achieves the balancing effect on the premise of safety and energy saving by performing active charging type balancing on batteries with low electric quantity in a storage battery pack.
Specifically, the invention provides a storage battery supplementary electric type active balancing device which is characterized by comprising the following components: the system comprises at least one equalization function module, a DC/DC converter, an active equalization power supply battery, an isolation measurement module and an isolation charging module, wherein all series-connected equalized battery packs of the equalization function module are connected to the active equalization power supply battery through the DC/DC converter; each balancing function module further comprises a bidirectional isolating switch array, the anode and the cathode of the balanced single battery of each balancing function module are connected to the bidirectional isolating switch array, the isolation measurement module circularly detects the voltage of the balanced single battery, and the MCU stores the information of the single battery with low electric quantity detected by the isolation measurement module; and the isolation charging module charges the single battery with low electric quantity according to the single battery information with low electric quantity provided by the MCU.
Furthermore, each balancing function module further comprises an arbitration unit, and each balancing function module further comprises an arbitration unit, wherein hardware of the arbitration unit is provided with an independent gating mechanism, so that when the bidirectional isolating switch array acts on the single batteries, at most only the positive end of one single battery is gated, and at most only the negative end of one battery is gated; one end of the arbitration unit is connected to the MCU, and the other end of the arbitration unit is respectively connected to the bidirectional isolating switch array, the isolating charging module and the isolating measurement module; when the MCU does not store the information of the single batteries with low electric quantity, the arbitration unit arbitrates the bidirectional isolating switch array, so that only one single battery is detected each time, and the isolation charging module is arbitrated not to work; when the MCU stores the information of the single batteries with low electric quantity, the arbitration unit arbitrates the bidirectional isolating switch array, so that only one single battery is charged at each time, and the isolation measurement module is arbitrated not to work.
Further, the MCU is a single chip microcomputer, an ARM or a DSP.
Further, the active equalization power supply battery is a rechargeable battery capable of realizing energy storage and with a conventional voltage of 12V or 24V.
Furthermore, the positive and negative ends of a single battery can be gated by selecting the bidirectional isolating switches of the positive and negative ends of the single battery;
the current direction of the switches in the bidirectional isolating switch array can flow in the forward direction or in the reverse direction.
Further, the isolation charging module outputs a constant current; according to the control of the MCU, stopping outputting the current when the output voltage is higher than a certain value; the input and the output of the isolation charging module are electrically isolated.
Further, the analog measurement end and the digital transmission end of the isolation measurement module are electrically isolated.
In another aspect, the present invention provides a method for balancing control by the storage battery supplementary electric active balancing apparatus, which comprises a measuring apparatus for measuring the voltage and current of the battery,
the method comprises the following steps:
recording selected data for the battery packs being equalized for use, said data comprising:
data (a), the maximum available capacity C0 of the battery pack;
the data (b) is obtained by testing, in the charging process of the single battery of the model, a region AC with the terminal voltage changing along with the SOC is selected, the mean value of the SOC in the region is Sac, the open-circuit voltage value UOac of the single battery of the model is Uhc when the single battery of the model is charged by a constant current Ih, the terminal voltage of the single battery of the model where the SOC is Sac is Uhc, and in the region, the change value of the terminal voltage Uhc and the fixed ratio value Rhc of the change value of the SOC are obtained;
data (c) is obtained through testing, in the discharging process of the single battery of the model, a region AD with terminal voltage changing sharply along with the SOC is selected, the mean value of the SOC in the region is Sad, the open-circuit voltage value UOad of the single battery of the model is discharged at a constant current Ih, the terminal voltage of the single battery of the model where the SOC is Sad is Uhd, and in the region, the change value of the terminal voltage Uhd and the fixed proportion value Rhd of the change value of the SOC are obtained;
the method further comprises the steps of:
step (1), recording the average current Ivs in the latest ts time, the average terminal voltage Uvn of the single batteries and the average value Uvs of the average terminal voltages of all the single batteries in the use process of the batteries,
equivalently, when charging or discharging at an Ivs constant current, the voltage of the single battery is Uvn, and the average voltage of all the single battery voltages in the battery pack is Uvs;
step (2), judging whether the battery pack accords with AC regional characteristics or AD regional characteristics, equating the average voltage Uvs of all the single battery voltages to be Uvhs which is the average equivalent voltage of all the single battery voltages under the condition of charging or discharging with a constant current Ih, and judging whether the battery pack accords with the method that,
judging method (a), the AC regional characteristic judging method is that Uvhs is larger than Uhc, and the difference value between Uvhs and Uhc is in a certain range, then the battery pack is considered to be in accordance with the AC regional characteristic,
judging method (b), the AD regional characteristic judging method is that Uvhs is less than Uhd, and the difference value of Uvhs and Uhc is in a certain range, the battery pack is considered to accord with the AD regional characteristic,
under constant current charging and constant current discharging, at a certain specific SOC value, the difference between the cell terminal voltage and the open circuit voltage (U-OCV) is in a substantially fixed proportion to I, so that the ratio (Uvhs-UOac)/Ih between the difference between the cell terminal voltage Uvhs and the open circuit voltage UOac when the SOC value is Sac and the constant current charging current Ih is equal to the ratio (Uvs-UOac)/Ivs between the difference between the cell terminal voltage Uvs and the open circuit voltage when the SOC value is svc and the Ivs, that is, the cell terminal voltage Uvhs = (Uvs-UOac): ih/Ivs + UOac) equivalent to Ih constant current charging, and similarly, when the SOC value is Sad, the Ivs constant current discharging is equivalent to Ih discharging terminal voltage relationship: uvhs = (Uvs-UOad) × Ih/Ivs + UOad;
step (3), when the characteristics of the battery in use accord with the region characteristics in the step (2), respectively calculating the difference value of the SOC of the single battery and the SOC of the battery pack in the region,
when the Ivs is charged with constant current, the monomer voltage Uvn is equivalent to the equivalent voltage Uvhn under the Ih charging, uvhn = (Uvn-UOac) × Ih/Ivs + UOac, and then the monomer voltage Uvn is equivalent to the difference Uvhs between Uvhs under the constant current charging Ih
＝(Uvn-UOac)*Ih/Ivs+UOac–((Uvs-UOac)*Ih/Ivs+UOac)
＝(Uvn-Uvs)*Ih/Ivs，
Similarly, when Ivs is discharged in constant current, the difference Uvhn-Uvhs =between Uvhn and Uvhs
＝(Uvn-UOad)*Ih/Ivs+UOad–((Uvs-UOad)*Ih/Ivs+UOad)
The calculation formula of = Uvn-Uvs, ih/Ivs, charging and discharging Uvhn-Uvhs is the same,
the constant current Ih charging or discharging end voltage curve is linearly equivalent near a certain SOC, the end voltage variation value is in proportional relation with the SOC variation value, under Ih constant current charging, when the SOC is Sac, the ratio is Rhc, under Ih constant current discharging, when the SOC is Sad, the ratio is Rhd, therefore, the difference between the cell SOC and the battery pack SOC is obtained by that the voltage variation value under charging or discharging is equal to Rhc or Rhd than the SOC variation value, and the difference between the cell SOC and the battery pack SOC is:
deviation value Secn of single battery and battery pack average SOC during constant current charging in AC region
＝(Uvhn-Uvhs)/Rhc
＝(Uvn-Uvs)*Ih/(Ivs*Rhc)，
The deviation value Sedn between the single battery and the average SOC of the battery pack during constant current discharge in the AD area
＝(Uvhn-Uvhs)/Rhd
＝(Uvn-Uvs)*Ih/(Ivs*Rhd)；
And (4) after the deviation value Secn and the deviation value Sedn are obtained simultaneously, the change values of the electric quantity of all the single batteries are equal according to the equal current in the series battery pack, the product of the estimated value Cn of the maximum available capacity of the single batteries and the change value of the SOC is obtained, and the product of the maximum available capacity C0 of the battery pack and the change value of the average SOC is equal, and Cn is obtained, so that
＝(Sac-Sdc)*C0/((Secn+Sac)-(Sedn+Sad))，
Then calculating the balance electric quantity Qn required by the deviation of the single battery pack from the middle value Sm
＝(Secn+Sac-Sm)*Cn-(Sac-Sm)*C0；
And (5) carrying out energy balance on the single battery according to the balance electric quantity Qn.
The invention has the beneficial effects that: the charging energy comes from the battery pack itself, and a spare battery or other energy sources are not needed; the arbitration unit enables only one single battery to be gated, and switches at the positive and negative ends of the other batteries are in an off state, so that the risk of short circuit of the batteries is eliminated; the arbitration unit arbitrates the isolated charging and the isolated measurement module for time division multiplexing, so that mutual influence is avoided; the expandable function module brings convenience and flexibility.
Drawings
Fig. 1 is a schematic block diagram of a supplementary power active equalization device for a storage battery pack according to the present invention.
FIG. 2 is a schematic diagram of an unbalanced state and an equalized target state in the equalizing method of the present invention;
fig. 3 is a flowchart of the battery pack equalization control of the present invention.
Detailed Description
The following describes embodiments of the present invention with reference to the drawings.
Fig. 1 is a schematic block diagram of a secondary battery pack charging type active balancing apparatus according to the present invention, which includes at least one balancing function module, and in one embodiment, the number of the balancing function modules is 3. All the series-connected equalized battery packs of the at least one equalization function module, in one embodiment, 12 series-connected batteries of one equalization function module, 12 × 3=36 series-connected equalized battery packs, are connected to an active equalization power supply battery through a DC/DC converter, the active equalization power supply battery is connected to an MCU, the MCU is further connected to an isolation measurement module and an isolation charging module of each equalization function module, and the isolation charging module is controlled to charge the corresponding single battery according to a measurement result of the isolation measurement module on the single battery of the corresponding equalization function module; each balancing function module further comprises a bidirectional isolating switch array, the anode and the cathode of the balanced single battery of each balancing function module are connected to the bidirectional isolating switch array, the isolation measurement module circularly detects the voltage of the balanced single battery, and the MCU stores the information of the single battery with low electric quantity detected by the isolation measurement module; and the isolation charging module charges the single battery with low electric quantity according to the single battery information with low electric quantity provided by the MCU.
The storage battery is a lithium battery; the active balanced power supply battery is a lead-acid battery, and the standard voltage of the battery is 24V in a preferred embodiment; the DC/DC can output 24V direct current voltage; the MCU is a single chip microcomputer, ARM or DSP, and in a preferred embodiment, the MCU is an ARM microcontroller. The isolation charging module is powered by an isolation power supply and can output a constant current of 200mA, 400mA or 600mA, in a preferred embodiment, a current of 400mA is output, and the output current is 0 when the output voltage is higher than 4.3V; the isolation measurement module is powered by an isolation power supply and uses a 16-bit high-precision analog-to-digital converter; the bidirectional isolating switch array can gate the positive end and the negative end of each single battery; the arbitration unit ensures that only one single battery is gated at the same time, and simultaneously ensures that the isolation acquisition and isolation measurement module performs time division multiplexing, namely, only one module acts at the same time. More specifically, the arbitration unit hardware is provided with an independent gating mechanism, so that when the bidirectional isolating switch array acts on the single batteries, at most only the positive end of one single battery is gated, and at most only the negative end of one battery is gated; one end of the arbitration unit is connected to the MCU, and the other end of the arbitration unit is respectively connected to the bidirectional isolating switch array, the isolating charging module and the isolating measurement module; when the MCU does not store the information of the single batteries with low electric quantity, the arbitration unit arbitrates the bidirectional isolating switch array, so that only one single battery is detected each time, and the isolation charging module is arbitrated not to work; when the MCU stores the information of the single batteries with low electric quantity, the arbitration unit arbitrates the bidirectional isolating switch array, so that only one single battery is charged at each time, and meanwhile, the isolation measurement module is arbitrated not to work.
The positive and negative ends of a single battery can be gated by selecting the bidirectional isolating switches at the positive and negative ends of the single battery, and the current directions of the switches in the bidirectional isolating switch array can flow in the forward direction or the reverse direction.
The voltage of all the series-connected equalized battery packs of the 3 equalizing functional modules is between 80V and 160V, the DC/DC charges the storage battery, the storage battery is guaranteed to have certain electric quantity, and meanwhile the storage battery provides working voltage for the MCU.
After each module of the storage battery electricity supplementing type active equalization device is electrified and initialized, the isolation measurement module performs training collection on 12 single batteries under the arbitration of the arbitration unit, and the isolation charging module does not work at the moment. And transmitting the collected information of all 12 single batteries to the MCU. The 3 modules are executed in parallel and simultaneously without mutual influence; the analog measurement end and the digital transmission end of the isolation measurement module are electrically isolated.
The MCU judges the batteries needing charging equalization in the 3 functional modules, and under the arbitration of the arbitration unit, the charging modules are guaranteed to be in action, and only one battery is charged at the same time. The 3 modules are executed in parallel and simultaneously without mutual influence. The isolation charging module outputs constant current; according to the control of the MCU, stopping outputting current when the output voltage is higher than a certain value; the input and the output of the isolation charging module are electrically isolated.
Therefore, the battery with low electric quantity can gradually supplement the electric quantity lower than that of other batteries under the continuous charge equalization, and the storage battery pack electricity supplementing type active equalization device is effective.
Example 2
Fig. 2 is a schematic diagram of an unbalanced state and an equalization target state when equalization is performed by the equalization apparatus shown in fig. 1.
As shown in the figure, it is assumed that the lithium battery pack is formed by connecting 6 single batteries in series, the 6 single batteries are represented by 6 rectangles respectively, the length of the rectangle represents the capacity of the battery, the 6 battery capacities are large or small, the 6 single batteries are connected in series, so that the current is the same, the change of the electric quantity is the same, and the blue dotted line represents the change of the electric quantity of the battery pack.
As can be seen from the unbalanced state (left diagram), the capacities and the SOCs of the 6 single batteries are different, the remaining battery capacity (blue dotted line) of the battery pack is shifted up when the battery pack is charged, the charging must be stopped when the full charge point of the battery pack No. 5 is reached, and therefore the charging is a cut-off line of the charging capacity, the remaining battery capacity (blue dotted line) of the battery pack is shifted down when the battery pack is discharged, and the discharging must be stopped when the full charge point of the battery pack No. 4 is reached, and therefore the discharging is a cut-off line of the discharging capacity. In the unbalanced state, the capacity of the battery pack is lost to some extent, and the capacity loss is determined by the difference between the capacities and the difference between the SOCs.
It can be seen from the target state (right diagram) to be achieved by the equalization control described in the present invention that the single battery is individually charged and discharged by the equalization device, so that the cut-off line of the charging electric quantity of the battery pack is consistent with the electric quantity full point of the single battery No. 4 with the minimum capacity, and the cut-off line of the discharging electric quantity of the battery pack is consistent with the electric quantity discharging completion point of the single battery No. 4 with the minimum capacity. The specific control method is to make the SOC of all the single batteries reach a certain intermediate value when the single batteries are charged or discharged.
Compared with the balanced target state and the unbalanced state, the available capacity of the battery pack reaching the balanced target state is obviously improved, and the full electric quantity point of the other 5 single batteries except the No. 4 battery in use avoid the charging cut-off point and the discharging cut-off point of the battery pack to the maximum extent, so that a certain guarantee margin is reserved for the capacity stability of the battery pack.
Fig. 2 is a flow chart of the equalization control according to the method of the present invention. Before executing the flow, the following data should be acquired first:
data (a), the maximum available capacity C0 of the battery pack, which may not be updated;
the data (b) is obtained by testing, in the charging process of the single battery of the model, a region AC with terminal voltage changing sharply along with the SOC is selected, the mean value of the SOC in the region is Sac, the open-circuit voltage value UOac of the single battery of the model is Uhc when the single battery of the model is charged by a constant current Ih, the terminal voltage of the single battery of the model where the SOC is Sac is Uhc, and the data (b) can not be updated when the change value of the terminal voltage Uhc and the change value of the SOC are a fixed proportion value Rhc;
and data (c) is obtained through testing, in the discharging process of the single battery of the model, a region AD in which the terminal voltage changes sharply along with the SOC is selected, the average value of the SOC in the region is Sad, the open-circuit voltage value UOad of the single battery of the model is discharged at a constant current Ih, the terminal voltage of the single battery of the model where the SOC is Sad is Uhd, and the data (c) can not be updated in the region, wherein the change value of the terminal voltage Uhd is a fixed proportion value Rhd of the change value of the SOC.
Data (d) is (Sac + Sad)/2 = sm when the areas AC and AD are selected.
Based on the above data, the program of the equalization control is divided into two parts, one part is equalization calculation, and the other part is equalization execution.
The equalization calculation is performed every ts time in the timing, and the steps are as follows:
(a1) Sampling and computing
Firstly, calculating the average value of sampling values of all single voltages and currents in ts time, assuming that k is a positive integer greater than 2 by k single batteries, the average voltage value of the single batteries is { Uv1, uv2, \ 8230;, uvk }, the average current is Ivs, and the average voltage value of the single batteries is Uvs = (Uv 1+ Uv2+ \ 8230; + Uvk)/k;
(a2) Judgment of
When charging, judging whether (Uvs-UOac) Ih/Ivs + UOac is larger than Uhc and the difference value with Uhc is in a certain range, then the battery pack is considered to accord with the AC region characteristic,
during discharging, judging whether (Uvs-UOad). Ih/Ivs + UOad is smaller than Uhd or not, and if the difference value between the Uhd and the (Uos-Iih) is within a certain range, determining that the battery pack conforms to the AD regional characteristics;
if yes, executing the next step (a 3), if not, not processing, and continuing to execute the sampling and calculation of (a 1);
(a3) Calculating SOC deviation value
Average SOC deviation value Secn between the nth single battery and the battery pack during charging
＝(Uvn-Uvs)*Ih/(Ivs*Rhc)，
Average SOC deviation value Sedn between the nth single battery and the battery pack during discharging
＝(Uvn-Uvs)*Ih/(Ivs*Rhd)，
According to the formula, the charging deviation and the discharging deviation arrays of all the single batteries relative to the average SOC of the battery pack are obtained as
{Sec1,Sec2,…,Seck}，
{Sed1,Sed2,…,Sedk}；
The equalization is executed in a timing mode, and the steps are as follows:
(b1) Judging whether a brand-new group of charging and discharging SOC deviation arrays are obtained, if so, calculating the balance electric quantity required by each battery, and executing balance, otherwise, not processing;
(b2) Calculating balance electric quantity, executing balance
Calculating formula Qon =according to balanced electric quantity of nth single battery
(Secn-Sedn) C0 h/2, wherein 0-straw-h-straw-1, adjusting the value according to the engineering condition,
calculating to obtain the balance electric quantity needed by all the single batteries
{Qo1,Qo2,…,Qok}，
And judging whether all the single batteries need to be balanced or not according to-Qd < Qon < Qc, if Qon is in accordance with the Qon, the nth single battery does not need to be balanced, otherwise, a balancing circuit is used for balancing electric quantity, the electric quantity is discharged regularly, and is charged if the electric quantity is negative, wherein the values of Qd and Qc are adjusted according to engineering test conditions.
The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention, so that various changes, modifications and equivalents of the embodiments of the present invention may be made within the scope of the claims of the present invention.
Claims (6)
1. A method for equalization control using a battery recharging active equalization apparatus, said battery recharging active equalization apparatus comprising: the battery pack to be equalized in series is connected to an active equalization power supply battery through a DC/DC converter, the active equalization power supply battery is connected to an MCU, the MCU is connected to an isolation measurement module and an isolation charging module of each equalization function module, and the isolation charging module is controlled to charge corresponding single batteries according to the measurement result of the isolation measurement module on the single batteries; each balancing function module further comprises a bidirectional isolating switch array, the positive electrode and the negative electrode of the balanced single battery of each balancing function module are connected to the bidirectional isolating switch array, the storage battery electricity supplementing type active balancing device comprises a measuring device for measuring the voltage and the current of the battery, and the method is characterized by comprising the following steps of:
recording selected data for the battery pack of the type being equalized for use, the data including:
data (a), the maximum available capacity C0 of the battery pack;
the data (b) is obtained by testing, in the charging process of the single battery of the model, a region AC with the terminal voltage changing along with the SOC is selected, the mean value of the SOC in the region is Sac, the open-circuit voltage value UOac of the single battery of the model is Uhc when the single battery of the model is charged by a constant current Ih, the terminal voltage of the single battery of the model where the SOC is Sac is Uhc, and in the region, the change value of the terminal voltage Uhc and the fixed ratio value Rhc of the change value of the SOC are obtained;
data (c) is obtained through testing, in the discharging process of the single battery of the model, a region AD with terminal voltage changing sharply along with the SOC is selected, the mean value of the SOC in the region is Sad, the open-circuit voltage value UOad of the single battery of the model is discharged at a constant current Ih, the terminal voltage of the single battery of the model where the SOC is Sad is Uhd, and in the region, the change value of the terminal voltage Uhd and the fixed proportion value Rhd of the change value of the SOC are obtained;
the method comprises the following steps:
step (1), recording the average current Ivs in the latest ts time, the average terminal voltage Uvn of the single batteries and the average value Uvs of the average terminal voltages of all the single batteries in the use process of the batteries,
equivalently, when the Ivs constant current is used for charging or discharging, the voltage of the single battery is Uvn, and the average voltage of all the single battery voltages in the battery pack is Uvs;
step (2), judging whether the battery pack accords with AC regional characteristics or AD regional characteristics, equating the average voltage Uvs of all the single battery voltages to be Uvhs which is the average equivalent voltage of all the single battery voltages under the condition of charging or discharging with a constant current Ih, and judging whether the battery pack accords with the method that,
the AC region characteristics are determined by Uvhs being greater than Uhc and Uvhs
If the difference value of the battery pack and the Uhc is within a certain range, the battery pack is considered to be in accordance with the AC region characteristic,
judging method (b), the AD regional characteristic judging method is that Uvhs is smaller than Uhd, and the difference value between Uvhs and Uhc is in a certain range, the battery pack is considered to accord with the AD regional characteristic,
under constant current charging and constant current discharging, at a certain specific SOC value, the difference between the cell terminal voltage and the open circuit voltage (U-OCV) is in a substantially fixed proportion to I, so that the ratio (Uvhs-UOac)/Ih between the difference between the cell terminal voltage Uvhs and the open circuit voltage UOac when the SOC value is Sac and the constant current charging current Ih is equal to the ratio (Uvs-UOac)/Ivs between the difference between the cell terminal voltage Uvs and the open circuit voltage when the SOC value is svc and the Ivs, that is, the cell terminal voltage Uvhs = (Uvs-UOac): ih/Ivs + UOac) equivalent to Ih constant current charging, and similarly, when the SOC value is Sad, the Ivs constant current discharging is equivalent to Ih discharging terminal voltage relationship: uvhs = (Uvs-UOad) × Ih/Ivs + UOad;
step (3), when the in-use characteristics of the battery conform to the region characteristics in the step (2), respectively calculating the difference value between the SOC of the single battery and the SOC of the battery pack in the region,
when the Ivs is charged with constant current, the monomer voltage Uvn is equivalent to the equivalent voltage Uvhn, uvhn = (Uvn-UOac) × Ih/Ivs + UOac under the Ih charging, and the equivalent voltage is equivalent to the difference Uvhn-Uvhs between Uvhn and Uvhs under the constant current charging Ih
=(Uvn-UOac)*Ih/Ivs+UOac – ( (Uvs-UOac)*Ih/Ivs+UOac)
=(Uvn- Uvs)*Ih/Ivs，
Similarly, when Ivs discharges at constant current, the difference Uvhn-Uvhs = Uvhs between Uvhn and Uvhs
=(Uvn-UOad)*Ih/Ivs+UOad – ( (Uvs-UOad)*Ih/Ivs+UOad)
=(Uvn- Uvs)*Ih/Ivs，
The constant current Ih charging or discharging end voltage curve is linearly equivalent near a certain SOC, the end voltage variation value is in proportional relation with the SOC variation value, the ratio is Rhc when the SOC is Sac under Ih constant current charging, the ratio is Rhd when the SOC is Sac, the ratio is Rhd when the SOC is Sad, therefore, the difference between the SOC of the single battery and the SOC of the battery pack is obtained by the voltage variation value ratio SOC variation value under charging or discharging being equal to Rhc or Rhd:
deviation value Secn between the single battery and the average SOC of the battery pack during constant current charging in the AC region
=(Uvhn-Uvhs)/ Rhc
=(Uvn-Uvs) *Ih/( Ivs *Rhc)，
The deviation value Sedn between the single battery and the average SOC of the battery pack during constant current discharge in the AD area
=(Uvhn-Uvhs)/ Rhd
=(Uvn-Uvs) *Ih/( Ivs *Rhd)；
And (4) after the deviation value Secn and the deviation value Sedn are obtained simultaneously, the change values of the electric quantity of all the single batteries are equal according to the equal current in the series battery pack, the product of the estimated value Cn of the maximum available capacity of the single batteries and the change value of the SOC is obtained, and the product of the maximum available capacity C0 of the battery pack and the change value of the average SOC is equal, and Cn is obtained, so that
= (Sac- Sad)* C0/((Secn+Sac)- (Sedn+Sad))，
Then calculating the balance electric quantity Qn required by the deviation of the single battery pack from the middle value Sm
=(Secn+Sac-Sm)* Cn-(Sac-Sm) *C0；
And (5) carrying out energy balance on the single battery according to the balance electric quantity Qn.
2. The method according to claim 1, wherein the isolation measurement module cyclically detects the voltage of the equalized single battery, and the MCU stores the information of the single battery with low electric quantity detected by the isolation measurement module; and the isolation charging module charges the single battery with low electric quantity according to the single battery information with low electric quantity provided by the MCU.
3. The method according to claim 2, wherein each equalization function module further comprises an arbitration unit, and hardware of the arbitration unit is provided with an independent gating mechanism, so that when the bidirectional isolating switch array acts on the single batteries, only the positive end of at most one single battery is gated, and only the negative end of at most one battery is gated; one end of the arbitration unit is connected to the MCU, and the other end of the arbitration unit is respectively connected to the bidirectional isolating switch array, the isolating charging module and the isolating measurement module; when the MCU does not store the information of the single batteries with low electric quantity, the arbitration unit arbitrates the bidirectional isolating switch array, so that only one single battery is detected each time, and the isolation charging module is arbitrated not to work; when the MCU stores the information of the single batteries with low electric quantity, the arbitration unit arbitrates the bidirectional isolating switch array, so that only one single battery is charged at each time, and meanwhile, the isolation measurement module is arbitrated not to work.
4. The method of claim 2, wherein the MCU is a single chip, an ARM, or a DSP.
5. The method according to any one of claims 1-3, wherein the active equalization power supply battery is a rechargeable battery capable of realizing energy storage and with a normal voltage of 12V or 24V.
6. The method of any of claims 1-4, wherein the isolated charging module outputs a constant current; according to the control of the MCU, stopping outputting current when the output voltage is higher than a certain value; the input and output ends of the isolated charging module are electrically isolated.
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| CN110112812B (en) * | 2019-06-26 | 2020-12-22 | 珠海格力电器股份有限公司 | Battery module active equalization method and system, control device and storage medium |
| CN110239396B (en) * | 2019-06-26 | 2021-09-17 | 山东大学 | Battery pack balancing module, system and control method based on bidirectional flyback converter |
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