Background technology
Electrokinetic cell is the power supply with electric loading such as electric tool, electric automobile, electric bicycle, emergency lighting.Electrokinetic cell is the battery pack that is in series by a plurality of cells, and the cell quantity of the high more required series connection of voltage is many more.Owing to the control precision reason of production process, the various electrochemical parameters of each cell there are differences, and the capacity of each cell, charge-discharge characteristic, initial condition are difficult to accomplish in full accord.A plurality of cells are connected into after battery pack makes electrokinetic cell, and the characteristic of each cell and the difference of state just are retained in the battery pack.Battery pack is in charging and discharge process, the electric current that each cell passed through in the battery pack is identical, because the existence of differences such as the characteristic of each battery and initial condition, the charged ability of each battery can not be not fully exerted, thereby the charging and the discharging efficiency of battery pack or electrokinetic cell have been reduced, more serious situation is, when the initial condition of each battery of forming battery pack and charge differ greatly, the part battery " overcharges " in the time of can causing charging, and part battery during discharge " is crossed and put "." overcharge " and " cross put " all can cause the irreversible damage of battery, the battery that damages can generate heat in charging that continues and discharge process in a large number, have a strong impact on the whole discharging efficiency and the overall useful life of electrokinetic cell, return charge and discharge process and bring potential safety hazard.
Patent ZL00137155.X discloses and a kind of series battery charge and discharge has been carried out the control circuit scheme; after this scheme will be formed each battery series connection of battery pack; detect the voltage of each battery in real time in charging and discharge process; the electric current of temperature and battery pack; the way of taking to reduce charge power or discharge power is protected each battery in the battery pack; this method can avoid battery " to overcharge " effectively; " cross and put "; " overheated "; but can not compensate the difference of initial condition of each battery of forming series battery and the difference of charge; the charged ability of each battery still can not be not fully exerted, and has still reduced the charging and the discharging efficiency of battery pack or electrokinetic cell.
Known another kind is to adopt equalizing circuit to carry out the serial connection charge controlling schemes; i.e. each battery two ends of battery pack after series connection clamp circuit in parallel; when certain battery reaches assigned voltage; clamp circuit work; method by shunting no longer raises the voltage of this battery, thereby reaches the purpose of protection battery.Clamp circuit has absorbed when this battery charges normal so-called energy more than needed, and this part energy dissipates by the heating of clamp circuit, is charged to the lithium battery of 4.2V for a joint, and when charging current is 5 ampere-hours, the dissipation power of clamp circuit heating can reach 21 watts.When the clamp circuit of a plurality of batteries is worked simultaneously, total heating power of clamp circuit is multiplied, for jumbo electrokinetic cell, need to use bigger charging current, the dissipation power of clamp circuit heating will be higher, a large amount of heatings cause control appliance huge, and the efficiency of energy utilization of charging process is low, also influences device security.
Summary of the invention
The object of the present invention is to provide a kind of circuit that series battery charge and discharge are controlled, the charged ability of each battery that is connected in the battery pack is not fully exerted, improve the service efficiency of electrokinetic cell, effectively avoid each over-charging of battery in the series battery, cross to put and take place, prolong the useful life of battery with overheated situation.In charging and the discharge process electric current of battery pack is monitored in real time,, guarantee to avoid the time safe in utilization the accidental damage of battery fortuitous events such as external short circuit, overcurrent enforcement hardware protection.
Invention solves the technical scheme that its technical problem adopted
Referring to Fig. 1, Fig. 2, Fig. 3, at the difference of the initial condition of each battery in the series battery and the difference of charge, traditional charging modes charges to the series connected battery group and discharges control, the charged ability of each battery can not be not fully exerted, the charging of battery pack or electrokinetic cell and the technical problem of discharging efficiency have been reduced, the present invention adopts the technical scheme that change over switch 2 is set between the battery 1 adjacent in the series connected battery group, charging and discharge process are by microcontroller 10 controls, and charging process adopts multistage constant current charge from high to low.Microcontroller 10 sends charge current level control coding to charging control circuit 11, after 22 decodings of control decoding circuit, deliver to current control circuit 20, control code conversion after current control circuit 20 will be deciphered is a current controling signal, deliver to constant-current control circuit 18, the electric current that constant-current control circuit 18 is adjusted charge circuit reaches the rated current value of corresponding charge level.In every grade of charging control, voltage detecting circuit 3 detects the terminal voltage of each battery in the series battery in real time, A/D change-over circuit 4 is converted to digital signal with voltage signal and gives microcontroller 10, when the terminal voltage that detects certain battery reaches the assigned voltage of this charge level, microcontroller 10 sends control signal to battery control switching circuit 12, battery control switching circuit 12 drives corresponding change over switch 2, stop this battery charge, calculate simultaneously the battery charging voltage and, and send the signal that changes AC/DC change-over circuit 19 output voltages to charging control circuit 11 on this basis, adjust through the output voltage of control decoding circuit 22 and 21 pairs of AC/DC change-over circuits 19 of voltage control circuit.
When the terminal voltage of all batteries of connecting all reaches assigned voltage, microcontroller 10 sends the signal of next charge level to charge controller 11, after 22 decodings of control decoding circuit, deliver to current control circuit 20, constant-current control circuit 18 is adjusted to the electric current of charge circuit in the electric current of next charge level defined, microcontroller 10 is sent control signal to battery switching circuit 12 simultaneously, discharges all change over switches, and all batteries enter other charged state of next stage.
After last other charging of level was finished, batteries charging finished.
In the charge or discharge process; current sensor 14 detects the charge or discharge electric current in real time; protective circuit 15 is compared the electric current that records with rated current; when overcurrent or short circuit take place; protective circuit 15 is sent control signal to charge/discharge switching circuit 16; cut off the charge/discharge loop, battery is protected.
In charging process, electric quantity metering circuit 13 to time integral, obtains the charge or discharge electric current ampere-hour number (AH) and gives microcontroller 10.Microcontroller 10 reads the ampere-hour number at interval with regular time in the charging process, calculate increment and with the terminal voltage of the current battery that is charging with multiply each other, obtain electric work increment (WH), microcontroller 10 is with electric work increment accumulative total, obtain the electric work amount of current battery pack, give LCD 6 and show.
In the discharge process, microcontroller 10 reads the ampere-hour number at interval with regular time, calculate decrement and with the terminal voltage of the current battery that is discharging with multiply each other, obtain electric work decrement (WH), microcontroller 10 deducts the electric work decrement and recomputates current electric work amount on the basis of the current electric work numerical quantity of battery pack, give LCD 6 and show.
Microcontroller 10 is saved in the electric work amount information of battery pack in the nonvolatile storage of electric quantity metering circuit 13, and the electric work amount information of battery pack can not lost because of power down.
Temperature sensor 5 is attached on each battery; directly measure the temperature of each battery; and send microcontroller 10 with the temperature signal of each battery; when certain battery occurring when overheated; microcontroller 10 sends control signal to charge/discharge switching circuit 16; turn-off the charge/discharge loop, realize the overtemperature protection to battery, LCD 6 shows overtemperature protection information simultaneously.
DC/DC translation circuit 8 obtains power supply from battery pack, is transformed into low-voltage, is the power supply of microcontroller 10 and each functional circuit.The switching of control switch 9 control DC/DC translation circuits 8.
During charging, (17c) (7a, 7b 7c) connect with electrokinetic cell connector 7 for 17a, 17b with charger connector 17.
During discharge, (23a, 23c) (7a 7c) connects with electrokinetic cell connector 7 with discharge load connector 23.
Beneficial effect of the present invention
The invention provides a kind of circuit that series battery charge and discharge are controlled, in charging process, each battery in the battery pack is carried out switching controls, efficiently solve the difference of the initial condition of each battery in the series battery, the difference of charge is to the influence of series connected battery group charge/discharge usefulness, the charged ability of each battery in the series battery is not fully exerted, improved the service efficiency of electrokinetic cell, effectively avoid each over-charging of battery in the series battery, cross to put and take place, prolong the useful life of battery with overheated situation.In charging and the discharge process electric current of battery pack is monitored in real time,, guarantee to avoid the time safe in utilization the accidental damage of battery fortuitous events such as external short circuit, overcurrent enforcement hardware protection.
Description of drawings
Fig. 1 is the functional circuit connection layout of the electrokinetic cell inside of multiple batteries series connection.
Fig. 2 is the charger function circuit connection diagram.
Fig. 3 is the discharge load connection layout.
Fig. 4 is the functional circuit connection layout of the electrokinetic cell inside of 4 batteries series connection.
Fig. 5 is the microcontroller program flow diagram
Among the figure, 1; battery, 2; change over switch; 3; voltage detecting circuit, 4; the A/D change-over circuit, 5; temperature sensor; 6; liquid crystal display circuit, 7; the electrokinetic cell connector, 8; the DC/DC translation circuit; 9; control switch, 10, microcontroller; 11; charging control circuit, 12; the battery control switching circuit, 13; the electric quantity metering circuit; 14; current sensor, 15; protective circuit, 16; the charge and discharge switch circuit; 17; the charger connector, 18; constant-current control circuit, 19; the AC/DC change-over circuit; 20; current control circuit; 21; voltage control circuit, 22; the control decoding circuit, 23; the discharge load connector; 24; use electric loading, 25; series battery
Embodiment
Referring to Fig. 3 and Fig. 4, the application of the present embodiment electrokinetic cell that series connection constitutes at 4 batteries.
Microcontroller 10 adopts the AT89S52 single-chip microcomputer; change over switch 2 adopts the JQX-15F electromagnetic relay; voltage detecting circuit 3 adopts the high common-mode voltage difference of MAX472 amplifier; A/D change-over circuit 4 adopts AD78888 passage analog-digital conversion ic; battery 1 uses 3.6V4AH lithium battery 4 joints; battery control switching circuit 12 adopts the 74hc373 integrated circuit; temperature sensor 5 adopts the LM75 digital temperature sensor; liquid crystal display circuit 6 adopts the standard character Liquid Crystal Module; DC/DC translation circuit 8 adopts MC33163 voltage raising and reducing integrated circuit; charging control circuit 11 adopts the 74hc373 integrated circuit; electric quantity metering circuit 13 adopts the DS2751AE integrated circuit with current time integration and current digital output; current sensor 14 adopts the sample resistance of 10 milliohms; protective circuit 15 adopts the LM358 operational amplifier; charge/discharge switching circuit 16 adopts the MTB30P06 field effect transistor; constant-current control circuit 18 adopts the MTB30P06 field effect transistor; current control circuit 20 adopts 1 Europe; 0.5 Europe; 0.2 Europe; 0.1 the sample resistance in Europe; and 2N8550 constitutes 4 grades of electric currents; voltage control circuit 21 adopts 1 74HC154 integrated circuit; control decoding circuit 22 adopts 2 74HC154, presses Fig. 4 and connects.
Work out microcontroller 10 programs by Fig. 5.
(17c) (7a, 7b 7c) connect, and AD/DC change-over circuit 19 is connected with the AC220V power supply, drive control switch 9, and battery pack is charged with electrokinetic cell connector 7 for 17a, 17b with charger connector 17.
(17a, 17c) (23a 23c) connects, and drives control switch 9, and battery pack is discharged with discharge load connector 23 with charger connector 17.