CN112104043A - Lithium battery equalization control circuit with charging and power supplementing functions and control method thereof - Google Patents
Lithium battery equalization control circuit with charging and power supplementing functions and control method thereof Download PDFInfo
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- CN112104043A CN112104043A CN202010998734.9A CN202010998734A CN112104043A CN 112104043 A CN112104043 A CN 112104043A CN 202010998734 A CN202010998734 A CN 202010998734A CN 112104043 A CN112104043 A CN 112104043A
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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
- H01M10/44—Methods for charging or discharging
- H01M10/441—Methods for charging or discharging for several batteries or cells simultaneously or sequentially
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/00302—Overcharge protection
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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
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/00308—Overvoltage protection
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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
The invention discloses a lithium battery equalization control circuit with charging and power supplementing functions and a control method thereofcAnd discharge MOS tube QdThe second end of the MCU main control unit is connected with the input end of the charge and discharge control unit, and the output end of the charge and discharge control unit is respectively connected with the charging MOS tube QcGrid and discharge MOS tube QdThe charging MOS transistor QcThe two ends of the charging circuit are connected in parallel with a charging compensation circuit; a corresponding control method is also disclosed. According to the invention, the charging and electricity supplementing circuit is added, so that the opening time of passive equalization is greatly prolonged, the equalization efficiency is obviously improved, and the lithium battery equalization error and error are reducedProbability and high cost performance.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a lithium battery equalization control circuit with a charging and power-supplementing function and a control method thereof.
Background
With the continuous progress of society, lithium batteries are suddenly increased as new energy, and the application of lithium batteries is gradually popularized in various fields, especially electric vehicles, such as electric cars, electric buses, electric vans, electric trucks, electric taxis and the like, and is gradually put into the market.
A lithium battery pack is composed of N strings of battery cores, and according to chemical characteristics, if the voltage difference between two strings of battery cores is too large, imbalance of electric quantity can be caused, for example, the voltage of one string of battery cores is 3.6V, the voltage of the other string of battery cores is 2.5V, and the battery is easily scrapped due to too large difference. If the difference between the maximum cell voltage and the minimum cell voltage reaches a certain limit, which results in a high probability of failure, neither discharge nor charge should be continued. In order to avoid this situation as much as possible, the BMS provided with the lithium battery is designed with a voltage balancing function. The BMS Battery Management System is called a Battery Management System, i.e., a module dedicated to the operation Management of the lithium Battery.
Voltage equalization is divided into two types, active and passive: passive equalization is to design hardware voltage, and use a voltage comparator, when the voltage of a certain string of batteries is too high compared with the voltage of other batteries (for example, the phase difference reaches 50 ms), or use another element to consume the electric quantity of the high-voltage battery, or pour the electric quantity of the high-voltage battery into the low-voltage battery; the active equalization is the same in principle, but more details of equalization can be controlled by a program, a serial-parallel decoder is used for making a switching circuit, a control system is only equalized in the charging process, and the equalized voltage threshold value and the like can be set more flexibly.
The lithium battery has special voltage platform characteristics, particularly the lithium iron phosphate battery, in the platform stage, more than about 85% of capacity is gathered in a voltage region of dozens of millivolts, a cell voltage-SOC (state of charge) correlation curve is very flat, the cell voltage-SOC correlation curve becomes a little steeper along with the increase of the internal resistance of a cell at the end of charging and discharging, but the capacity of the two stages of charging and discharging is usually only about 10% of the total capacity.
Based on this characteristic of lithium cell, when current many strings of lithium cell BMS battery management system's passive balanced function used, had following limitation:
1. the equalization time is shorter. The start time of the passive equalization can be arranged at the charging end of the battery module, but the capacity of the charging end only occupies less than 5% of the capacity of the battery cell, so that the start time of the passive equalization is short.
2. The phenomena of error equalization and error equalization exist. Some BMSs are balancing time prolonging, balancing start voltage is reduced to a lithium battery voltage platform, but the existing battery cell voltage acquisition circuit has deviation in identifying real battery cell voltage precision due to the reason of precision, so that the balance is not started on the battery cell with higher SOC, the balance is started on the battery cell with lower SOC by mistake instead, and the nonuniformity of the module battery cell SOC is further deteriorated.
Disclosure of Invention
The invention provides a lithium battery equalization control circuit with a charging and power supplementing function and a control method thereof to solve the technical problem.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
according to a first aspect of the embodiments of the present invention, a lithium battery equalization control circuit is provided, including an MCU main control unit, a charge and discharge control unit, and a battery core group formed by a plurality of battery cells connected in series, where a first end of the MCU main control unit is electrically connected to each battery cell through a collection and equalization circuit unit, and the charge and discharge control unit includes an MOS drive circuit and a charging MOS transistor QcAnd discharge MOS tube QdThe second end of the MCU main control unit is connected with the input end of the charge and discharge control unit, and the output end of the charge and discharge control unit is respectively connected with the charging MOS tube QcGrid and discharge MOS tube QdGrid of (1), charging MOS tube QcDrain electrode of and discharge MOS tube QdIs connected with the drain electrode of the discharge MOS tube QdThe source electrode of the charging MOS tube Q is connected with the negative electrode of the electric core groupcThe two ends of the charging circuit are connected in parallel with a charging compensation circuit.
Preferably, the charging and power-supplementing circuit comprises a power-supplementing MOS tube QbAnd a compensation resistor RpThe power supply MOS tube QbDrain electrode of and charging MOS tube QcIs connected with the drain electrode of the resistor RpAre respectively connected with a power-compensating MOS tube QbSource electrode, charging MOS tube QcOf the substrate.
Preferably, the acquisition and equalization circuit unit includes a sampling circuit and a plurality of cell equalization circuits connected in parallel to two ends of the cell, and the cell equalization circuits are electrically connected to the sampling circuit.
Preferably, the cell balancing circuit includes a balancing resistor and a balancing MOS transistor connected in series, a drain of the balancing MOS transistor is connected to an anode of the cell, two ends of the balancing resistor are respectively connected to a cathode of the cell and a source of the balancing MOS transistor, and a gate of the balancing MOS transistor is electrically connected to the sampling circuit.
Preferably, if the voltage value of one of the battery cells is greater than the equalization start voltage, and the difference between the battery cell voltage value and the lowest battery cell voltage value is greater than a first difference, the passive equalization of the battery cell is started; and if the voltage value of one of the battery cells after the passive equalization is started is smaller than the equalization starting voltage, or the voltage value of the battery cell after the passive equalization is started is larger than the equalization starting voltage and the difference value between the battery cell voltage value and the lowest battery cell voltage value is smaller than a second difference value, the passive equalization of the battery cell is closed.
Preferably, the battery cores are lithium iron phosphate batteries, the balanced starting voltage of each battery core is 3.45V, the first difference is 50mV, and the second difference is 20 mV.
Preferably, the battery core group is a lithium iron phosphate battery, and when the battery core is subjected to overvoltage protection and the highest battery core voltage value is less than 3.55V or the lowest battery core voltage value is greater than the battery core overvoltage protection recovery voltage value, the charging and power supplementing circuit is started; and if the difference value between the highest cell voltage value and the lowest cell voltage value is smaller than the second difference value and the highest cell voltage value is larger than the equalizing starting voltage or the highest cell voltage value is larger than the cell over-charging protection voltage, closing the charging and electricity supplementing circuit.
Preferably, the cell equalizing start voltage is 3.45V, the cell overvoltage protection recovery voltage value is 3.34V, the cell overcharge protection voltage is 3.65V, and the second difference is 20 mV.
According to a second aspect of the embodiments of the present invention, there is provided a lithium battery equalization control method, which is applied to the lithium battery equalization control circuit described above, where the battery CELL group includes n battery CELLs CELLiI and n are positive integers, i is more than or equal to 1 and less than or equal to n, and the electric core group is a lithium iron phosphate battery, and the method comprises the following steps:
101, the MCU main control unit charges the MOS tube QcCharging the cell group and acquiring the voltage value of each cell through the acquisition and equalization circuit unit;
step 102, when the voltage value U of the ith battery cell CELLiAfter the voltage is higher than the equilibrium starting voltage, if the difference value between the ith CELL voltage value and the lowest CELL voltage value is larger than the first difference value, the CELL CELL is openediIs balanced to the switch QiCELL CELL of open CELLiPassive equalization of (2);
step 103, charging the MOS transistor QcContinuously charging the cell group until the highest cell voltage value UCELLmaxOver-charge protection is triggered to turn off the charging MOS tube Q by more than 3.65Vc；
104, in the charging process, when the highest cell voltage value U is obtainedCELLmax<3.55V and lowest cell voltage value UCELLminThe voltage value is higher than the overvoltage protection recovery voltage value of the battery cell, and the power-supplementing MOS tube Q is openedbContinuously supplementing electricity through an electricity supplementing circuit when the highest cell voltage value U is reachedCELLmaxWhen the voltage is higher than the overcharge protection voltage of the battery cell, the power-supplementing MOS tube Q is closedb；
Step 105, the highest cell voltage value U thereafterCELLmaxIn the falling process, when the highest cell voltage value U is obtainedCELLmax<3.55V and lowest cell voltage value UCELLminThe power supply MOS tube Q is restarted when the voltage value is higher than the cell overvoltage protection recovery voltage valuebStep 104 is repeatedly executed, so that the voltage of each cell which starts the balancing is always kept above the balancing starting voltage;
step 106, when the CELL CELL of the balance is startediVoltage value U of CELLiWith the lowest cell voltage value UCELLminIs less than the secondDifference value, and CELL CELLiVoltage value U of CELLiWhen the voltage is larger than the balanced starting voltage or the CELL CELLiVoltage value U of CELLi CELL CELL is closed when the voltage is lower than the balanced starting voltageiCELL of the equalization switchiCELL CELL is closediPassive equalization of (2);
step 107, when the difference value U between the highest cell voltage value and the lowest cell voltage valueCELLmax-UCELLminLess than the second difference and the highest cell voltage value UCELLmaxWhen the voltage is larger than the balanced opening voltage, the power-supplementing MOS tube Q is closedbAnd closing all the passive equalization of the started passive equalization cells.
Preferably, the balanced starting voltage of each battery cell is 3.45V, the battery cell overvoltage protection recovery voltage value is 3.34V, the battery cell overcharge protection voltage is 3.65V, the first difference is 50mV, and the second difference is 20 mV.
Compared with the prior art, the charging and power supplementing circuit is added in the charging control loop of the BMS battery management system, so that the starting time of passive equalization is greatly prolonged, the equalization efficiency is obviously improved, the probability of lithium battery equalization error and error is reduced, and the cost performance is high; through this electricity circuit that mends that charges, can be under certain conditions can control the voltage of all series connection electricity cores within less scope (like 20 mV), and can not trigger the monomer protection of charging, by voltage breakdown's risk when reducing the monomer and overcharging the charge switch cut off the heavy current when protecting, increase BMS reliability of work.
Drawings
Fig. 1 is a circuit diagram of a lithium battery equalization control circuit with charging and power supplementing functions according to the present invention.
In the figure, 1-MCU main control unit, 2-charge and discharge control unit, 3-acquisition and equalization circuit unit, 4-charge compensation circuit, 5-MOS drive circuit, and 6-sampling circuit.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments shown in the drawings. These embodiments are not intended to limit the present invention, and structural, methodological, or functional changes made by those skilled in the art according to these embodiments are included in the scope of the present invention.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.
As shown in fig. 1, a lithium battery equalization control circuit with charging and power-compensating functions comprises an MCU main control unit 1, a charging and discharging control unit 2 and a plurality of battery cells connected in series to form a battery cell group, wherein a first end of the MCU main control unit 1 is electrically connected with each battery cell through a collecting and equalizing circuit unit 3, the charging and discharging control unit 1 comprises an MOS drive circuit 5 and a charging MOS transistor QcAnd discharge MOS tube QdThe second end of the MCU main control unit 1 is connected with the input end of the charge and discharge control unit 2, and the output end of the charge and discharge control unit 2 is respectively connected with a charging MOS (metal oxide semiconductor) tube QcGrid and discharge MOS tube QdGrid of (1), charging MOS tube QcDrain electrode of and discharge MOS tube QdIs connected with the drain electrode of the discharge MOS tube QdThe source electrode of the charging MOS tube Q is connected with the negative electrode of the electric core groupcAnd the two ends of the charging circuit are connected in parallel with a charging compensation circuit 4.
The electric core group adopted by the invention generally consists of n electric cores CELLiAre connected in series, wherein i and n are positive integers, and i is more than or equal to 1 and less than or equal to n. The MCU main control unit 1 is a main control chip and peripheral circuits of the BMS battery management system, is used for acquiring battery core data and driving the charge and discharge control unit 2, and realizes the balance control of the lithium battery.
In an embodiment of the present invention, the charge compensation circuit 4 may include a compensation MOS transistor QbAnd a compensation resistor RpWherein the MOS tube Q is compensatedbDrain electrode of and charging MOS tube QcIs connected with the drain electrode of the resistor RpAre respectively connected with a power-compensating MOS tube QbSource electrode, charging MOS tube QcOf the substrate.
The acquisition and equalization circuit unit 3 comprises a sampling circuit 6 for acquiring voltage values of each battery cell and a plurality of battery cell equalization circuits which are connected in parallel at two ends of each battery cell and used for equalizing the voltage of each battery cell, and the battery cell equalization circuits are electrically connected with the sampling circuit 6.
Specifically, each CELL balancing circuit includes a balancing resistor and a balancing MOS transistor connected in series, a drain of the balancing MOS transistor is connected to an anode of the CELL, and two ends of the balancing resistor are respectively connected to a cathode of the CELL and a source of the balancing MOS transistor, as shown in fig. 1, connected in parallel to the CELLnEqualizing resistance R at both endsnAnd balanced MOS transistor QnAnd the grid electrode of each equalizing MOS tube is connected to the sampling circuit 6. The structure of the sampling circuit 6 and the connection between the gate of the equalizing MOS transistor and the sampling circuit 6 are conventional circuits, and are not described herein.
Here, the passive equalization logic of each cell is as follows: if the voltage value of one of the battery cells is greater than the balance starting voltage, and the difference value between the battery cell voltage value and the lowest battery cell voltage value is greater than a first difference value, starting the passive balance of the battery cell; and if the voltage value of one of the battery cells after the passive equalization is started is smaller than the equalization starting voltage, or the voltage value of the battery cell after the passive equalization is started is larger than the equalization starting voltage and the difference value between the battery cell voltage value and the lowest battery cell voltage value is smaller than a second difference value, the passive equalization of the battery cell is closed.
Here, the electric core group generally adopts the lithium iron phosphate battery, all generally is equipped with overvoltage protection. The on and off conditions of the charging and replenishing circuit 4 are as follows: when the cell overvoltage protection is performed, and the highest cell voltage value is less than 3.55V or the lowest cell voltage value is greater than the cell overvoltage protection recovery voltage value, the charging and power supplementing circuit is started, namely, the power supplementing MOS tube Q is startedb(ii) a If the difference value between the highest cell voltage value and the lowest cell voltage value is smaller than the second difference value and the highest cell voltage value is larger than the equilibrium starting voltage or the highest cell voltage value is larger than the cell overcharge protection voltage, the charging and electricity supplementing circuit is closed, namely the electricity supplementing MOS tube Q is turned offb。
The balance starting voltage of each battery cell is 3.45V, the battery cell overvoltage protection recovery voltage value is 3.34V, the battery cell overcharge protection voltage is 3.65V, and the second difference value is 20 mV. These values are chosen based on a number of tests and experience.
The invention connects a charging and power supplementing circuit 4 composed of an electronic switch and a power resistor in series with a lithium battery BMS charging loop control switch in parallel, and constructs a novel BMS battery management system connected with a battery core group. After the lithium battery is fully charged and meets a certain voltage condition, the charging and electricity supplementing circuit 4 is started, so that the low-current charging of the battery can be realized, the equalization time is prolonged, the risks of equalization error and error equalization are reduced, and the voltage of all series-connected battery cells in the module can be controlled in a smaller range (such as 20 mV) under a certain condition, the single charging protection is prevented from being triggered, the probability of turning off a charging protection switch under a high-current condition is reduced, and the reliability of the system is improved.
Based on the lithium battery equalization control circuit, the invention provides a lithium battery equalization control method, which comprises the following steps:
101, the MCU main control unit charges the MOS tube QcCharging the cell group and acquiring the voltage value of each cell through the acquisition and equalization circuit unit;
step 102, when the voltage value U of the ith battery cell CELLiAfter the voltage is higher than the equilibrium starting voltage, if the difference value between the ith CELL voltage value and the lowest CELL voltage value is larger than the first difference value, the CELL CELL is openediIs balanced to the switch QiCELL CELL of open CELLiPassive equalization of (2);
step 103, charging the MOS transistor QcContinuously charging the cell group until the highest cell voltage value UCELLmaxOver-charge protection is triggered to turn off the charging MOS tube Q by more than 3.65Vc；
104, in the charging process, when the highest cell voltage value U is obtainedCELLmax<3.55V and lowest cell voltage value UCELLminThe voltage value is higher than the overvoltage protection recovery voltage value of the battery cell, and the power-supplementing MOS tube Q is openedbContinuously supplementing electricity through an electricity supplementing circuit when the highest cell voltage value U is reachedCELLmaxWhen the voltage is higher than the overcharge protection voltage of the battery cell, the power-supplementing MOS tube Q is closedb. At this time, the batteryAt the end stage of charging, the CELL voltage-SOC curve is steeper, and the CELL voltage can be maintained above the equilibrium starting voltage by a smaller electricity supplementing current, namely CELLnThe passive equalization of (2) can continue;
step 105, the highest cell voltage value U thereafterCELLmaxIn the falling process, when the highest cell voltage value U is obtainedCELLmax<3.55V and lowest cell voltage value UCELLminThe power supply MOS tube Q is restarted when the voltage value is higher than the cell overvoltage protection recovery voltage valuebStep 104 is repeatedly executed, so that the voltage of each cell which starts the balancing is always kept above the balancing starting voltage;
step 106, when the CELL CELL of the balance is startediVoltage value U of CELLiWith the lowest cell voltage value UCELLminIs less than the second difference, and the CELL CELLiVoltage value U of CELLiWhen the voltage is larger than the balanced starting voltage or the CELL CELLiVoltage value U of CELLi CELL CELL is closed when the voltage is lower than the balanced starting voltageiCELL of the equalization switchiCELL CELL is closediPassive equalization of (2);
step 107, when the difference value U between the highest cell voltage value and the lowest cell voltage valueCELLmax-UCELLminLess than the second difference and the highest cell voltage value UCELLmaxWhen the voltage is larger than the balanced opening voltage, the power-supplementing MOS tube Q is closedbAnd closing all the passive equalization of the started passive equalization cells.
Therefore, the balance of the lithium battery module is completed, and the voltage difference values of all the series-connected battery cores are controlled to be smaller than the second difference value.
The balance starting voltage of each battery cell is 3.45V, the battery cell overvoltage protection recovery voltage value is 3.34V, the battery cell overcharge protection voltage is 3.65V, the first difference value is 50mV, and the second difference value is 20 mV.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.
Claims (10)
1. The utility model provides a lithium cell equalization control circuit of function of replenishing electricity charges in area, a serial electric core group of forming is established ties including MCU main control unit, charge-discharge control unit and a plurality of electricity core, the first end of MCU main control unit is connected with each electricity core electricity through gathering and equalizer circuit unit, charge-discharge control unit includes MOS drive circuit, the MOS pipe Q that chargescAnd discharge MOS tube QdThe second end of the MCU main control unit is connected with the input end of the charge and discharge control unit, and the output end of the charge and discharge control unit is respectively connected with the charging MOS tube QcGrid and discharge MOS tube QdGrid of (1), charging MOS tube QcDrain electrode of and discharge MOS tube QdIs connected with the drain electrode of the discharge MOS tube QdThe source electrode of the charging MOS tube Q is connected with the negative electrode of the electric core groupcThe two ends of the charging circuit are connected in parallel with a charging compensation circuit.
2. The lithium battery equalization control circuit with charging and power-supplementing functions as claimed in claim 1, wherein the charging and power-supplementing circuit comprises a power-supplementing MOS (metal oxide semiconductor) tube QbAnd a compensation resistor RpThe power supply MOS tube QbDrain electrode of and charging MOS tube QcIs connected with the drain electrode of the resistor RpAre respectively connected with a power-compensating MOS tube QbSource electrode, charging MOS tube QcOf the substrate.
3. The lithium battery equalization control circuit with the charging and power supplementing function according to claim 2, wherein the acquisition and equalization circuit unit comprises a sampling circuit and a plurality of cell equalization circuits connected in parallel to two ends of the cell, and the cell equalization circuits are electrically connected with the sampling circuit.
4. The lithium battery equalization control circuit with the charging and power supplementing function according to claim 3, wherein the cell equalization circuit comprises an equalization resistor and an equalization MOS (metal oxide semiconductor) tube which are connected in series, a drain electrode of the equalization MOS tube is connected with an anode of the cell, two ends of the equalization resistor are respectively connected with a cathode of the cell and a source electrode of the equalization MOS tube, and a grid electrode of the equalization MOS tube is electrically connected with the sampling circuit.
5. The lithium battery equalization control circuit with the charging and power-supplementing function according to claim 4, wherein if the voltage value of one of the battery cells is greater than the equalization start voltage, and the difference between the battery cell voltage value and the lowest battery cell voltage value is greater than a first difference, the passive equalization of the battery cell is started; and if the voltage value of one of the battery cells after the passive equalization is started is smaller than the equalization starting voltage, or the voltage value of the battery cell after the passive equalization is started is larger than the equalization starting voltage and the difference value between the battery cell voltage value and the lowest battery cell voltage value is smaller than a second difference value, the passive equalization of the battery cell is closed.
6. The lithium battery equalization control circuit with the charging and power-supplementing function according to claim 5, wherein the battery core group is a lithium iron phosphate battery, the equalization starting voltage of each battery core is 3.45V, the first difference is 50mV, and the second difference is 20 mV.
7. The lithium battery equalization control circuit with the charging and power-supplementing function according to claim 5, wherein the battery core group is a lithium iron phosphate battery, and when the cell overvoltage protection is performed and the highest cell voltage value is less than 3.55V or the lowest cell voltage value is greater than the cell overvoltage protection recovery voltage value, the charging and power-supplementing circuit is started; and if the difference value between the highest cell voltage value and the lowest cell voltage value is smaller than the second difference value and the highest cell voltage value is larger than the equalizing starting voltage or the highest cell voltage value is larger than the cell over-charging protection voltage, closing the charging and electricity supplementing circuit.
8. The lithium battery equalization control circuit with the charging and power-supplementing function according to claim 7, wherein the equalization start voltage of each battery cell is 3.45V, the battery cell overvoltage protection recovery voltage value is 3.34V, the battery cell overcharge protection voltage value is 3.65V, and the second difference value is 20 mV.
9. A lithium battery equalization control method is applied to the lithium battery equalization control circuit of any one of claims 3 to 8, and the battery core group comprises n battery CELLs CELLiI and n are positive integers, i is more than or equal to 1 and less than or equal to n, and the electric core group is a lithium iron phosphate battery, and is characterized by comprising the following steps:
101, the MCU main control unit charges the MOS tube QcCharging the cell group and acquiring the voltage value of each cell through the acquisition and equalization circuit unit;
step 102, when the voltage value U of the ith battery cell CELLiAfter the voltage is higher than the equilibrium starting voltage, if the difference value between the ith CELL voltage value and the lowest CELL voltage value is larger than the first difference value, the CELL CELL is openediIs balanced to the switch QiCELL CELL of open CELLiPassive equalization of (2);
step 103, charging the MOS transistor QcContinuously charging the cell group until the highest cell voltage value UCELLmaxOver-charge protection is triggered to turn off the charging MOS tube Q by more than 3.65Vc；
104, in the charging process, when the highest cell voltage value U is obtainedCELLmax<3.55V and lowest cell voltage value UCELLminThe voltage value is higher than the overvoltage protection recovery voltage value of the battery cell, and the power-supplementing MOS tube Q is openedbContinuously supplementing electricity through an electricity supplementing circuit when the highest cell voltage value U is reachedCELLmaxWhen the voltage is higher than the overcharge protection voltage of the battery cell, the power-supplementing MOS tube Q is closedb；
Step 105, the highest cell voltage value U thereafterCELLmaxIn the falling process, when the highest cell voltage value U is obtainedCELLmax<3.55V and lowest cell voltage value UCELLminHigher than the over-voltage protection recovery voltage value of the battery coreRe-starting the power-compensating MOS transistor QbStep 104 is repeatedly executed, so that the voltage of each cell which starts the balancing is always kept above the balancing starting voltage;
step 106, when the CELL CELL of the balance is startediVoltage value U of CELLi With the lowest cell voltage value UCELLminIs less than the second difference, and the CELL CELLiVoltage value U of CELLi Greater than the equilibrium turn-on voltage or CELL CELLiVoltage value U of CELLi CELL CELL is closed when the voltage is lower than the balanced starting voltageiIs balanced to the switch QiCELL CELL is closediPassive equalization of (2);
step 107, when the difference value U between the highest cell voltage value and the lowest cell voltage valueCELLmax-UCELLminLess than the second difference and the highest cell voltage value UCELLmaxWhen the voltage is larger than the balanced opening voltage, the power-supplementing MOS tube Q is closedbAnd closing all the passive equalization of the started passive equalization cells.
10. The lithium battery equalization control method of claim 9, wherein the equalization start voltage of each cell is 3.45V, the cell overvoltage protection recovery voltage value is 3.34V, the cell overcharge protection voltage value is 3.65V, the first difference is 50mV, and the second difference is 20 mV.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010998734.9A CN112104043A (en) | 2020-09-22 | 2020-09-22 | Lithium battery equalization control circuit with charging and power supplementing functions and control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202010998734.9A CN112104043A (en) | 2020-09-22 | 2020-09-22 | Lithium battery equalization control circuit with charging and power supplementing functions and control method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112531834A (en) * | 2020-11-27 | 2021-03-19 | 杭州微慕科技有限公司 | Battery pack charging and discharging control system and method |
| CN112701766A (en) * | 2021-03-23 | 2021-04-23 | 广东高斯宝电气技术有限公司 | Single battery passive equalization circuit structure and battery pack passive equalization control method |
| CN116169738A (en) * | 2022-12-07 | 2023-05-26 | 浙江高泰昊能科技有限公司 | BMS active equalization circuit and working method thereof |
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2020
- 2020-09-22 CN CN202010998734.9A patent/CN112104043A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112531834A (en) * | 2020-11-27 | 2021-03-19 | 杭州微慕科技有限公司 | Battery pack charging and discharging control system and method |
| CN112701766A (en) * | 2021-03-23 | 2021-04-23 | 广东高斯宝电气技术有限公司 | Single battery passive equalization circuit structure and battery pack passive equalization control method |
| CN112701766B (en) * | 2021-03-23 | 2021-06-25 | 广东高斯宝电气技术有限公司 | Single battery passive equalization circuit structure and battery pack passive equalization control method |
| CN116169738A (en) * | 2022-12-07 | 2023-05-26 | 浙江高泰昊能科技有限公司 | BMS active equalization circuit and working method thereof |
| CN116169738B (en) * | 2022-12-07 | 2024-04-16 | 浙江高泰昊能科技有限公司 | BMS active equalization circuit and working method thereof |
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