CN204068216U

CN204068216U - The balanced protection circuit of lithium battery

Info

Publication number: CN204068216U
Application number: CN201420447032.1U
Authority: CN
Inventors: 黄国文; 杨圣峯; 何鹏; 彭建普
Original assignee: Guangxi Zhuo Neng New Energy Technology Co Ltd
Current assignee: Guangxi Zhuo Neng New Energy Technology Co Ltd
Priority date: 2014-08-08
Filing date: 2014-08-08
Publication date: 2014-12-31
Anticipated expiration: 2024-08-08

Abstract

The utility model relates to the balanced protection circuit of lithium battery, and it comprises: sample circuit, balancing circuitry, under-voltage protecting circuit, comparison circuit, drive circuit, the first reference voltage, the second reference voltage, supply voltage and State-output circuit; Comparison circuit, for the first reference voltage and the second reference voltage being compared with the sampling battery voltage of corresponding lithium battery respectively, and exports one first level signal; State-output circuit, for the first level signal exported according to all comparison circuits, exports a second electrical level signal; Drive circuit, for according to second electrical level signal and the first corresponding level signal, judges whether the balancing circuitry output drive signal to correspondence; Balancing circuitry, for the drive singal according to correspondence, the positive pole controlling corresponding lithium battery is connected with negative pole, to make to carry out discharge process to the lithium battery of correspondence.The utility model has the low advantage of cost of manufacture.

Description

The balanced protection circuit of lithium battery

Technical field

The utility model relates to the protective circuit technology of lithium battery, is specifically related to the protective circuit technology of multi-series lithium battery.

Background technology

Now commercially the protective circuit of multi-string lithium ion battery has following situation:

1. hardware Acquisition Circuit and MCU control;

2. the IC that goes here and there single gathers and controls more;

3. many single-unit cascade IC gather and control;

Scheme 1 software and hardware combining, adds the complexity of circuit, with high costs; Scheme 2 is confined to the function of IC, joint number is restricted (although it maximumly can detect that n batteries is connected, but can might not use from 2-n joint), or end balance (namely just starting balancing circuitry under the fast full condition of single battery) that can only charge; Scheme 3 is that cost is high equally, or only has end equilibrium function.

Because the consensus of cell in lithium ion battery bag causes cell to overcharge and after to one's heart's content condition; protective circuit on market just can process for the problem that monomer battery voltage pressure reduction is smaller; long-term accumulation; monomer battery voltage pressure reduction will increase gradually; after whole charge and discharge process completes; battery does not still reach the balance of voltage; the balancing circuitry of multi-string lithium ion battery bag circuit protection plate was lost efficacy gradually; the power output of battery strings reduces simultaneously, and the useful life of power brick shortens.

Utility model content

The purpose of this utility model is the balanced protection circuit proposing a kind of lithium battery, the problem that its energy workout cost is high.

In order to achieve the above object, the technical scheme that adopts of the utility model is as follows:

A kind of balanced protection circuit of lithium battery, the quantity of described lithium battery is at least two, and all lithium batteries are connected in series, described balanced protection circuit comprises: all identical with the quantity of described lithium battery and the sample circuit, balancing circuitry, under-voltage protecting circuit, comparison circuit and the drive circuit that connect one to one with described lithium battery, one first reference voltage, one second reference voltage, a supply voltage and a State-output circuit;

Described sample circuit, for obtaining the sampling battery voltage of corresponding lithium battery;

Described under-voltage protecting circuit, for judging whether the sampling battery voltage of corresponding lithium battery is greater than described first reference voltage, if so, then disconnects with corresponding balancing circuitry, if not, then the positive pole and the negative pole that control the lithium battery in corresponding balancing circuitry disconnect;

Described comparison circuit, for the first reference voltage and the second reference voltage being compared with the sampling battery voltage of corresponding lithium battery respectively, and exports one first level signal;

Described State-output circuit, for the first level signal exported according to all comparison circuits, exports a second electrical level signal;

Described drive circuit, for according to second electrical level signal and the first corresponding level signal, judges whether the balancing circuitry output drive signal to correspondence;

Described balancing circuitry, for the drive singal according to correspondence, the positive pole controlling corresponding lithium battery is connected with negative pole, to make to carry out discharge process to the lithium battery of correspondence;

Described supply voltage, for providing operating voltage for sample circuit, under-voltage protecting circuit, comparison circuit and State-output circuit.

The balanced protection circuit of another kind of lithium battery of the present utility model, the quantity of described lithium battery is at least two, and all lithium batteries are connected in series, described balanced protection circuit comprises: all identical with the quantity of described lithium battery and the sample circuit, balancing circuitry and the under-voltage protecting circuit that connect one to one with described lithium battery, at least one primary control comparison circuit, a final stage control comparison circuit, a reference voltage output circuit and a supply voltage;

At least one primary control comparison circuit be designated as respectively the 1st grade of control comparison circuit, the 2nd grade control comparison circuit ..., N level controls comparison circuit, N >=1 and be natural number; Described primary control comparison circuit comprises elementary comparison circuit, elementary first State-output circuit, elementary second State-output circuit, primary control circuit and first stage drive circuit; Wherein, the 1st grade of control comparison circuit provides operating voltage by described supply voltage;

Final stage controls comparison circuit and comprises final stage comparison circuit, final stage State-output circuit and final driving circuit;

Elementary comparison circuit, first stage drive circuit, final stage comparison circuit are all identical with the quantity of lithium battery with the quantity of final driving circuit and connect one to one with lithium battery respectively;

Described reference voltage output circuit, for export (N+2) individual reference voltage, described (N+2) individual reference voltage be designated as respectively the 1st reference voltage, the 2nd reference voltage ..., N+2 reference voltage; 1st reference voltage < the 2nd reference voltage < ... < N+2 reference voltage;

Described under-voltage protecting circuit, for judging whether the sampling battery voltage of corresponding lithium battery is greater than described 1st reference voltage, if so, then disconnects with corresponding balancing circuitry, if not, then the positive pole and the negative pole that control the lithium battery in corresponding balancing circuitry disconnect;

Described multiple primary control comparison circuit, successively for the sampling battery voltage of the lithium battery according to correspondence, judges whether that controlling corresponding balancing circuitry carries out discharge process to the lithium battery of correspondence, specific as follows:

Described 1st grade of control comparison circuit, for the 1st reference voltage and the 2nd reference voltage being compared with the sampling battery voltage of corresponding lithium battery respectively by its elementary comparison circuit, and exports one the 11st elementary level signal; One the 12nd elementary level signal is exported according to all 11st elementary level signals by its elementary first State-output circuit; One the 13rd elementary level signal is exported according to all 11st elementary level signals by its elementary second State-output circuit; Judge whether to export the 11st elementary drive singal to the first stage drive circuit of correspondence according to the 12nd elementary level signal and the 13rd elementary level signal by its primary control circuit, and judge whether to provide operating voltage to the 2nd grade of control comparison circuit; By its first stage drive circuit according to the 11st elementary drive singal and the 11st elementary level signal, judge whether that the balancing circuitry to correspondence exports the 12nd elementary drive singal;

Described 2nd grade of control comparison circuit, for the 2nd reference voltage and the 3rd reference voltage being compared with the sampling battery voltage of corresponding lithium battery respectively by its elementary comparison circuit, and exports one the 21st elementary level signal; One the 22nd elementary level signal is exported according to all 21st elementary level signals by its elementary first State-output circuit; One the 23rd elementary level signal is exported according to all 21st elementary level signals by its elementary second State-output circuit; Judge whether to export the 21st elementary drive singal to the first stage drive circuit of correspondence according to the 22nd elementary level signal and the 23rd elementary level signal by its primary control circuit, and judge whether that controlling comparison circuit to 3rd level provides operating voltage; By its first stage drive circuit according to the 21st elementary drive singal and the 21st elementary level signal, judge whether that the balancing circuitry to correspondence exports the 22nd elementary drive singal;

……；

Described N level controls comparison circuit, for N reference voltage and N+1 reference voltage being compared with the sampling battery voltage of corresponding lithium battery respectively by its elementary comparison circuit, and exports the elementary level signal of a N1; The elementary level signal of a N2 is exported according to the elementary level signal of all N1 by its elementary first State-output circuit; The elementary level signal of a N3 is exported according to the elementary level signal of all N1 by its elementary second State-output circuit; Judge whether to export the elementary drive singal of N1 to the first stage drive circuit of correspondence according to the elementary level signal of N2 and the elementary level signal of N3 by its primary control circuit, and judge whether that controlling comparison circuit to final stage provides operating voltage; By its first stage drive circuit according to the elementary drive singal of N1 and the elementary level signal of N1, judge whether to export the elementary drive singal of N2 to the balancing circuitry of correspondence;

Described final stage controls comparison circuit, for N+1 reference voltage and N+2 reference voltage being compared with the sampling battery voltage of corresponding lithium battery respectively by its final stage comparison circuit, and exports one first final stage level signal; One second final stage level signal is exported according to all first final stage level signals by its final stage State-output circuit; Judge whether to export final stage drive singal to the balancing circuitry of correspondence according to the second final stage level signal and the first corresponding final stage level signal by its final driving circuit;

Described balancing circuitry, for according to the 12nd elementary drive singal of correspondence or the 22nd elementary drive singal or the elementary drive singal of N2 or final stage drive singal, the positive pole controlling corresponding lithium battery is connected with negative pole, to make to carry out discharge process to the lithium battery of correspondence;

Described supply voltage, for providing operating voltage for sample circuit and under-voltage protecting circuit.

Preferably, described sample circuit comprises the first to the 5th resistance and differential amplifier, the inverting input of differential amplifier is connected with the negative pole of corresponding lithium battery by the 3rd resistance, the normal phase input end of differential amplifier is connected with the positive pole of corresponding lithium battery by the 4th resistance, the normal phase input end of differential amplifier is also by the 5th grounding through resistance, the inverting input of differential amplifier is also by the first grounding through resistance, the inverting input of differential amplifier is also connected with the output of differential amplifier by the second resistance, the output of differential amplifier exports the sampling battery voltage of corresponding lithium battery.

Preferably; described under-voltage protecting circuit comprises the 6th to the 9th resistance, operational amplifier and the first triode; the inverting input of operational amplifier is connected with the sampling battery voltage of corresponding lithium battery by the 6th resistance; the normal phase input end of operational amplifier is connected with the 1st reference voltage by the 7th resistance; the output of operational amplifier is connected with the base stage of the first triode by the 8th resistance; the output of operational amplifier is also by the 9th grounding through resistance; the grounded emitter of the first triode, the collector electrode of the first triode is connected with the control end of balancing circuitry.

Preferably, described balancing circuitry comprises photoelectrical coupler, tenth to the 12 resistance and the first metal-oxide-semiconductor, the drain electrode of the first metal-oxide-semiconductor is connected with the positive pole of corresponding lithium battery by the 11 resistance, the source electrode of the first metal-oxide-semiconductor connects with the negative pole of corresponding lithium battery, the transistor emitter output of photoelectrical coupler is connected with the grid of the first metal-oxide-semiconductor, the transistor emitter output of photoelectrical coupler is also connected with the negative pole of corresponding lithium battery by the 12 resistance, the transistor collector input of photoelectrical coupler is connected with the positive pole of corresponding lithium battery by the 11 resistance, the diode input of photoelectrical coupler all connects with the output of corresponding under-voltage protecting circuit and the output of corresponding drive circuit.

Preferably, described elementary comparison circuit comprises the 13 to the 16 resistance, first voltage comparator, second voltage comparator, first diode and the second diode, the normal phase input end of the first voltage comparator is connected with N reference voltage by the 14 resistance, the inverting input of the first voltage comparator is connected with described sampling battery voltage by the 13 resistance, the inverting input of the second voltage comparator is connected with N+1 reference voltage by the 16 resistance, the normal phase input end of the second voltage comparator is connected with described sampling battery voltage by the 15 resistance, the output of the first voltage comparator is connected with the anode of the first diode, the negative electrode of the first diode and the corresponding input of elementary first State-output circuit, the corresponding first input end of first stage drive circuit and the input of the correspondence of elementary second State-output circuit connect, the output of the second voltage comparator is connected with the anode of the second diode, and the negative electrode of the second diode is connected with the negative electrode of the first diode.

Preferred further, described elementary first State-output circuit comprises the first State-output electronic circuit identical with the quantity of lithium battery, each first State-output electronic circuit comprises the 17 resistance, 18 resistance and the second triode, the base stage of the second triode is connected with the output of corresponding elementary comparison circuit by the 18 resistance, the base stage of the second triode is also connected with described supply voltage by the 17 resistance, the grounded collector of the second triode, the emitter of the second triode is connected with the first input end of primary control circuit, the emitter of the second triode of one of them the first State-output electronic circuit is also connected with described supply voltage by 1 the 19 resistance,

Described elementary second State-output circuit comprises three diode identical with the quantity of lithium battery and the 23 resistance, 3rd triode and the 20 to the 22 resistance, each the 3rd diode forms a series arm with one the 23 corresponding resistant series, one end of each series arm connects with the output of corresponding elementary comparison circuit, the other end of each series arm is connected with the base stage of the 3rd triode, the base stage of the 3rd triode is by the 22 grounding through resistance, the emitter of the 3rd triode is by the 21 grounding through resistance, the emitter of the 3rd triode is connected with the second input of primary control circuit, the collector electrode of the 3rd triode is connected with described supply voltage by the 20 resistance,

Described primary control circuit comprises reduction voltage circuit, the 24 to the 37 resistance, the 3rd to the 4th metal-oxide-semiconductor, the 4th to the 6th triode, the 4th diode, the 5th diode, first to fourth electric capacity, tertiary voltage comparator and the 4th voltage comparator, described reduction voltage circuit is used for described supply voltage to be converted to a comparison voltage, the inverting input of tertiary voltage comparator is connected with described comparison voltage by the 24 resistance, the normal phase input end of tertiary voltage comparator is connected with one end of the 25 resistance, the other end of the 25 resistance is as the second input of the primary control circuit of the corresponding levels, the inverting input of the 4th voltage comparator is connected with one end of the 26 resistance, the other end of the 26 resistance is as the first input end of the primary control circuit of the corresponding levels, the normal phase input end of the 4th voltage comparator is connected with comparison voltage by the 27 resistance, the output of tertiary voltage comparator is connected with the base stage of the 4th triode by the 28 resistance, the base stage of the 4th triode is by the 30 grounding through resistance, the grounded emitter of the 4th triode, the emitter of the 4th triode is connected with the second input of corresponding first stage drive circuit by the first electric capacity, the collector electrode of the 4th triode is connected with the grid of the second metal-oxide-semiconductor, the collector electrode of the 4th triode is connected with the drain electrode of the second metal-oxide-semiconductor by the 31 resistance, the source electrode of the second metal-oxide-semiconductor and the second input of corresponding first stage drive circuit, the base stage of the 4th triode is all connected by the output of the 29 resistance with the 4th voltage comparator with the base stage of the 5th triode, the base stage of the 5th triode is connected with the source electrode of the 4th metal-oxide-semiconductor by the 37 resistance, the grounded collector of the 5th triode and being connected with the source electrode of the 3rd metal-oxide-semiconductor by the second electric capacity, the source electrode of the 3rd metal-oxide-semiconductor is used for providing operating voltage for the primary control comparison circuit of next stage, the emitter of the 5th triode is connected with the drain electrode of the 3rd metal-oxide-semiconductor by the 32 resistance, the emitter of the 5th triode is connected with the grid of the 3rd metal-oxide-semiconductor, the drain electrode of the second metal-oxide-semiconductor is all connected with the source electrode of the 4th metal-oxide-semiconductor with the drain electrode of the 3rd metal-oxide-semiconductor, the drain electrode of the 4th metal-oxide-semiconductor is connected with described supply voltage, the first input end of primary control circuit at the corresponding levels is connected with the base stage of the 34 resistance with the 6th triode by the 4th diode successively, the first input end of primary control circuit at the corresponding levels is connected with the base stage of the 35 resistance with the 6th triode by the 5th diode successively, the base stage of the 6th triode is by the 36 grounding through resistance, the grounded emitter of the 6th triode and being connected with the source electrode of the 4th metal-oxide-semiconductor by the 3rd electric capacity, the collector electrode of the 6th triode is connected with the grid of the 4th metal-oxide-semiconductor, the collector electrode of the 6th triode is connected with described supply voltage by the 33 resistance,

Described just stage drive circuit, comprise the 38 to the 42 resistance, 6th diode and the 7th triode, the collector electrode of the 7th triode is connected with one end of the 38 resistance, the other end of the 38 resistance is as the second input of first stage drive circuit, the base stage of the 7th triode is connected with the negative electrode of the 6th diode by the 39 resistance, the anode of the 6th diode is as the first input end of first stage drive circuit, the base stage of the 7th triode is by the 41 grounding through resistance, the anode of the 6th diode is by the 40 grounding through resistance, the emitter of the 7th triode is by the 42 grounding through resistance, the emitter of the 7th triode connects with the control end of corresponding balancing circuitry.

Preferably, described final stage comparison circuit comprises the 43 to the 46 resistance, 5th voltage comparator, 6th voltage comparator, 7th diode and the 8th diode, the normal phase input end of the 5th voltage comparator is connected with N+1 reference voltage by the 44 resistance, the inverting input of the 5th voltage comparator is connected with described sampling battery voltage by the 43 resistance, the inverting input of the 6th voltage comparator is connected with N+2 reference voltage by the 46 resistance, the normal phase input end of the 6th voltage comparator is connected with described sampling battery voltage by the 45 resistance, the output of the 5th voltage comparator is connected with the anode of the 7th diode, the negative electrode of the 7th diode connects with the corresponding input of final stage State-output circuit and the first input end of corresponding final driving circuit, the output of the 6th voltage comparator is connected with the anode of the 8th diode, and the negative electrode of the 8th diode is connected with the negative electrode of the 7th diode.

Preferred further, described final stage State-output circuit comprises nine diode identical with the quantity of lithium battery and the 43 resistance, 8th triode and the 44 to the 45 resistance, each the 9th diode forms a series arm with one the 43 corresponding resistant series, one end of each series arm connects with the output of corresponding final stage comparison circuit, the other end of each series arm is connected with the base stage of the 8th triode, the base stage of the 8th triode is by the 45 grounding through resistance, the grounded emitter of the 8th triode and being connected with the source electrode of the 5th metal-oxide-semiconductor by the 4th electric capacity, the source electrode of the 5th metal-oxide-semiconductor is connected with the second input of final driving circuit, the collector electrode of the 8th triode is connected with described supply voltage by the 44 resistance and is connected with the drain electrode of described 5th metal-oxide-semiconductor, the collector electrode of the 8th triode is connected with the grid of the 5th metal-oxide-semiconductor,

Described final driving circuit, comprise the 48 to the 50 resistance, tenth diode and the 9th triode, the collector electrode of the 9th triode is connected with one end of the 48 resistance, the other end of the 48 resistance is as the second input of final driving circuit, the base stage of the 9th triode is connected with the negative electrode of the tenth diode by the 47 resistance, the anode of the tenth diode is as the first input end of final driving circuit, the base stage of the 9th triode is by the 49 grounding through resistance, the anode of the 9th diode is by the 46 grounding through resistance, the emitter of the 9th triode is by the 50 grounding through resistance, the emitter of the 9th triode connects with the control end of corresponding balancing circuitry.

The utility model has following beneficial effect:

Under charging, electric discharge, leaving standstill three kinds of situations, the balance of real-time controlling lithium battery, ensures the consistency of lithium battery voltage, thus makes the life of lithium battery string, volume output promotes, and improves stability and the reliability of lithium battery string.And the utility model is without the need to using MCU and IC, and cost is low.

Accompanying drawing explanation

Fig. 1 is the functional-block diagram of the balanced protection circuit of the lithium battery of the utility model embodiment one;

Fig. 2 is the functional-block diagram of the balanced protection circuit of the lithium battery of the utility model embodiment two;

Fig. 3 is the syndeton schematic diagram that in Fig. 2, the 1st grade of control comparison circuit and final stage control comparison circuit;

Fig. 4 is the circuit diagram of the sample circuit of Fig. 2;

Fig. 5 is the circuit diagram of the under-voltage protecting circuit of Fig. 2;

Fig. 6 is the circuit diagram of the balancing circuitry of Fig. 2;

Fig. 7 is the circuit diagram of the elementary comparison circuit of Fig. 3;

Fig. 8 is the circuit diagram of the elementary first State-output circuit of Fig. 3;

Fig. 9 is the circuit diagram of the elementary second State-output circuit of Fig. 3;

Figure 10 is the circuit diagram of the primary control circuit of Fig. 3;

Figure 11 is the circuit diagram of the first stage drive circuit of Fig. 3;

Figure 12 is the circuit diagram of the final stage comparison circuit of Fig. 3;

Figure 13 is the circuit diagram of the final stage State-output circuit of Fig. 3;

Figure 14 is the circuit diagram of the final driving circuit of Fig. 3.

Embodiment

Below, by reference to the accompanying drawings and embodiment, the utility model is described further.

Embodiment one

As shown in Figure 1, a kind of balanced protection circuit of lithium battery, the quantity of described lithium battery is at least two, and all lithium batteries are connected in series.Described balanced protection circuit comprises: all identical with the quantity of described lithium battery and the sample circuit, balancing circuitry, under-voltage protecting circuit, comparison circuit and the drive circuit that connect one to one with described lithium battery, one first reference voltage, one second reference voltage, a supply voltage and a State-output circuit.

Described sample circuit (can with reference to figure 4), for obtaining the sampling battery voltage of corresponding lithium battery, described sampling battery voltage can be the half of the virtual voltage of lithium battery.Normal voltage range due to lithium battery is 3-4.2V, and therefore, the first reference voltage is 1.5V, and the second reference voltage is 2.1V.First reference voltage and the second reference voltage can by supply voltage by voltage conversion circuit transformations.

Described under-voltage protecting circuit (can with reference to figure 5); for judging whether the sampling battery voltage of corresponding lithium battery is greater than described first reference voltage; if; then disconnect with corresponding balancing circuitry; to make balancing circuitry not by the control of under-voltage protecting circuit; if not, then the positive pole and the negative pole that control the lithium battery in corresponding balancing circuitry disconnect, and stop discharge process to make balancing circuitry to lithium battery.

Described comparison circuit (can with reference to figure 7 or Figure 12), for the first reference voltage and the second reference voltage being compared with the sampling battery voltage of corresponding lithium battery respectively, and exports one first level signal.Such as, if sampling battery voltage is between the first reference voltage and the second reference voltage, then the first level signal is low level signal, otherwise is high level signal.

Described State-output circuit (can with reference to Figure 13), for the first level signal exported according to all comparison circuits, exports a second electrical level signal.Such as, if the first all level signals is low level signal, then second electrical level signal is also low level signal, if wherein there is one first level signal to be high level signal, then second electrical level signal is high level signal.

Described drive circuit (can with reference to Figure 14), for according to second electrical level signal and the first corresponding level signal, judges whether the balancing circuitry output drive signal to correspondence.Such as, second electrical level signal is low level signal, then illustrate that the first corresponding level signal is also low level signal, drive circuit is output drive signal not, if second electrical level signal is high level signal, and the first level signal of correspondence is high level signal, then drive circuit output drive signal is to the balancing circuitry that connect corresponding to it.

Described balancing circuitry (can with reference to figure 6); for the drive singal according to correspondence; the positive pole controlling corresponding lithium battery is connected with negative pole; to make to carry out discharge process to the lithium battery of correspondence, until the sampling battery voltage that under-voltage protecting circuit determines corresponding lithium battery is less than or equal to described first reference voltage.

Described supply voltage, for providing operating voltage for sample circuit, under-voltage protecting circuit, comparison circuit and State-output circuit.Supply voltage can be provided by DC power supply, also by civil power through direct current transformation circuit conversion, or can be provided by power-supply battery.

Embodiment two

Shown in composition graphs 2 to Figure 14, the balanced protection circuit of another kind of lithium battery, the present embodiment is described for two lithium batteries and two-step evolution comparison circuit.Two lithium batteries are connected in series.Described balanced protection circuit comprises: two sample circuits, two balancing circuitrys, two under-voltage protecting circuits, a primary control comparison circuit, final stages control comparison circuit, a reference voltage output circuit and a supply voltage VCC.

Because the primary control comparison circuit of the present embodiment only has one, institute thinks the 1st grade of control comparison circuit.1st grade of control comparison circuit comprises elementary comparison circuit, elementary first State-output circuit, elementary second State-output circuit, primary control circuit and first stage drive circuit.1st grade of control comparison circuit provides operating voltage by described supply voltage.

Final stage controls comparison circuit and comprises final stage comparison circuit, final stage State-output circuit and final driving circuit.

Elementary comparison circuit, first stage drive circuit, final stage comparison circuit are all identical with the quantity of lithium battery with the quantity of final driving circuit and connect one to one with lithium battery respectively.

Described reference voltage output circuit, for exporting 3 reference voltages, 3 reference voltages are designated as the 1st reference voltage, the 2nd reference voltage, the 3rd reference voltage respectively.1st reference voltage < the 2nd reference voltage < the 3rd reference voltage.Normal voltage range due to lithium battery is 3-4.2V, and therefore, the 1st reference voltage is 1.5V, and the 2nd reference voltage is 1.8V, and the 3rd reference voltage is 2.1V.1st reference voltage, the 2nd reference voltage and the 3rd reference voltage all can by supply voltage VCC by voltage conversion circuit transformations.

As shown in Figure 4, described sample circuit, for obtaining the sampling battery voltage of corresponding lithium battery.Quantity due to sample circuit is 2, is designated as the 1st sample circuit and the 2nd sample circuit respectively.1st sample circuit is made up of resistance R1, resistance R12 to R14, differential amplifier U1.2nd sample circuit is made up of resistance R3 to R7, differential amplifier U11.Concrete annexation is described with the 2nd sample circuit, the inverting input of differential amplifier U11 is connected with the negative pole B1 of corresponding lithium battery by resistance R3, the normal phase input end of differential amplifier U11 is connected with the positive pole B2 of corresponding lithium battery by resistance R4, the normal phase input end of differential amplifier U11 is also by resistance R6 ground connection, the inverting input of differential amplifier U11 is also by resistance R7 ground connection, the inverting input of differential amplifier U11 is also connected with the output of differential amplifier U11 by resistance R5, the output of differential amplifier U11 exports the sampling battery voltage BATV2 of corresponding lithium battery.Differential amplifier U11 and differential amplifier U1 all has supply voltage VCC to power.The syndeton of the 1st sample circuit and the syndeton of the 2nd sample circuit similar, difference is only that the inverting input of the differential amplifier U1 of the 1st sample circuit is by the direct ground connection of resistance R12, therefore, an earth resistance of an inverting input can be omitted, this is the positive pole of the lithium battery connecing correspondence due to terminal B1, and the direct ground connection of the negative pole of this lithium battery.Sampling battery voltage is the half of the virtual voltage of lithium battery.

As shown in Figure 5, described under-voltage protecting circuit, for judging whether the sampling battery voltage of corresponding lithium battery is greater than described 1st reference voltage; if; then disconnect with corresponding balancing circuitry, if not, then the positive pole and the negative pole that control the lithium battery in corresponding balancing circuitry disconnect.Quantity due to under-voltage protecting circuit is 2, is designated as the 1st under-voltage protecting circuit and the 2nd under-voltage protecting circuit respectively.1st under-voltage protecting circuit is made up of resistance R109 to R112, triode Q13 and operational amplifier U29.2nd under-voltage protecting circuit is made up of resistance R113 to R116, triode Q15 and operational amplifier U30.The explanation of syndeton is carried out for the 1st under-voltage protecting circuit; the inverting input of operational amplifier U29 is connected with the sampling battery voltage BATV1 of corresponding lithium battery by resistance R109; the normal phase input end of operational amplifier U29 is connected with the 1st reference voltage by resistance R110; the output of operational amplifier U29 is connected with the base stage of triode Q13 by resistance R111; the output of operational amplifier U29 is also by resistance R112 ground connection; the grounded emitter of triode Q13, the collector electrode of triode Q13 connects with the control end DISC_01 of corresponding balancing circuitry.

Shown in composition graphs 7 to Figure 11, described 1st grade of control comparison circuit, for the 1st reference voltage and the 2nd reference voltage being compared with the sampling battery voltage of corresponding lithium battery respectively by its elementary comparison circuit, and exports one the 11st elementary level signal; One the 12nd elementary level signal is exported according to all 11st elementary level signals by its elementary first State-output circuit; One the 13rd elementary level signal is exported according to all 11st elementary level signals by its elementary second State-output circuit; Judge whether to export the 11st elementary drive singal to the first stage drive circuit of correspondence according to the 12nd elementary level signal and the 13rd elementary level signal by its primary control circuit, and judge whether that controlling comparison circuit to final stage provides operating voltage; By its first stage drive circuit according to the 11st elementary drive singal and the 11st elementary level signal, judge whether that the balancing circuitry to correspondence exports the 12nd elementary drive singal.

As shown in Figure 7, the quantity of elementary comparison circuit is 2, is designated as the 1st elementary comparison circuit and the 2nd elementary comparison circuit respectively.1st elementary comparison circuit is made up of resistance R166 to R167, voltage comparator U43-A, voltage comparator U43-B, diode D2 and diode D3.2nd elementary comparison circuit is made up of resistance R2, resistance R161 to R163, voltage comparator U42-A, voltage comparator U42-B, diode D4 and diode D5.Annexation explanation is carried out for the 1st elementary comparison circuit, the normal phase input end of voltage comparator U43-B is connected with the 1st reference voltage by resistance R164, the inverting input of voltage comparator U43-B is connected with sampling battery voltage BATV1 by resistance R166, the inverting input of voltage comparator U43-A is connected with the 2nd reference voltage by resistance R167, the normal phase input end of voltage comparator U43-A is connected with described sampling battery voltage BATV1 by resistance R165, the output of voltage comparator U43-B is connected with the anode of diode D2, the negative electrode of diode D2 and the corresponding input (DRIVE1) of elementary first State-output circuit, the corresponding first input end (DRIVE1) of first stage drive circuit and the input (DRIVE1) of the correspondence of elementary second State-output circuit connect, the output of voltage comparator U43-1 is connected with the anode of diode D3, and the negative electrode of diode D3 is connected with the negative electrode of diode D2.

As shown in Figure 8, described elementary first State-output circuit comprises 2 the first State-output electronic circuits, is designated as the 1st electronic circuit and the 2nd electronic circuit respectively.1st electronic circuit is made up of resistance R671, resistance R672 and triode Q113, and the 2nd electronic circuit is made up of resistance R674, resistance R675 and triode Q114.Syndeton explanation is carried out for the 1st electronic circuit, the base stage of triode Q113 is connected with the output (DRIVE1) of corresponding elementary comparison circuit by resistance R672, the base stage of triode Q113 is also connected with described supply voltage VCC by resistance R671, the grounded collector of triode Q113, the emitter of triode Q113 is connected with the first input end (STATE00) of primary control circuit.1st electronic circuit and the difference of the 2nd electronic circuit are only that the emitter of the triode Q113 of the 1st electronic circuit is also connected with described supply voltage VCC by a resistance R673.

As shown in Figure 9, described elementary second State-output circuit comprises diode D162, diode D163, resistance R376, resistance R377, triode Q29, resistance R390, resistance R389 and resistance R713.Diode D162 connects with resistance R376 formation one first series arm, one end of first series arm connects with the output (DRIVE1) of corresponding elementary comparison circuit, the other end of the first series arm is connected with the base stage of triode Q29, diode D163 connects with resistance R377 formation one second series arm, one end of second series arm connects with the output (DRIVE2) of corresponding elementary comparison circuit, the other end of the second series arm is connected with the base stage of triode Q29, the base stage of triode Q29 is by resistance R390 ground connection, the emitter of triode Q29 is by resistance R713 ground connection, the emitter of triode Q29 is connected with second input (STATE01) of primary control circuit, the collector electrode of triode Q29 is connected with described supply voltage VCC by resistance R389.

As shown in Figure 10, the syndeton of described primary control circuit is: comprise the reduction voltage circuit that supply voltage VCC to be converted to a comparison voltage by, described contrast potential is 1/3 of supply voltage VCC, described reduction voltage circuit comprises resistance R711 and resistance R712, supply voltage VCC is successively by resistance R711 and resistance R712 ground connection, and the connected node of resistance R711 and resistance R712 is for exporting described comparison voltage.The inverting input of voltage comparator U100 is connected with described contrast potential by resistance R445, the normal phase input end of voltage comparator U100 is connected with one end of resistance R446, the other end of resistance R446 is as second input (STATE01) of the primary control circuit of the corresponding levels, the inverting input of voltage comparator U115 is connected with one end of resistance R437, the other end of resistance R437 is as the first input end (STATE00) of the primary control circuit of the corresponding levels, the normal phase input end of voltage comparator U115 is connected with comparison voltage by resistance R618, the output of voltage comparator U100 is connected with the base stage of triode Q37 by resistance R449, the base stage of triode Q37 is by resistance R448 ground connection, the grounded emitter of triode Q37, the emitter of triode Q37 is connected with second input (CHANNEL0) of corresponding first stage drive circuit by electric capacity C11, the collector electrode of triode Q37 is connected with the grid of metal-oxide-semiconductor Q35, the collector electrode of triode Q37 is connected with the drain electrode of metal-oxide-semiconductor Q35 by resistance R444, the source electrode of metal-oxide-semiconductor Q35 and second input (CHANNEL0) of corresponding first stage drive circuit, the base stage of triode Q37 is all connected with the output of voltage comparator U115 by resistance R436 with the base stage of triode Q98, the base stage of triode Q98 is connected with the source electrode of metal-oxide-semiconductor Q33 by resistance R716, the grounded collector of triode Q98 and being connected with the source electrode of metal-oxide-semiconductor Q27 by electric capacity C12, the source electrode of metal-oxide-semiconductor Q27 is used for providing operating voltage (POWER00) for final stage controls comparison circuit, the emitter of triode Q98 is connected with the drain electrode of metal-oxide-semiconductor Q27 by resistance R714, the emitter of triode Q98 is connected with the grid of metal-oxide-semiconductor Q27, the drain electrode of metal-oxide-semiconductor Q35 is all connected with the source electrode of metal-oxide-semiconductor Q33 with the drain electrode of metal-oxide-semiconductor Q27, the drain electrode of metal-oxide-semiconductor Q33 is connected with described supply voltage VCC, the first input end of primary control circuit at the corresponding levels leads to diode D197 successively and is connected with the base stage of triode Q80 with resistance R577, the first input end of primary control circuit at the corresponding levels is connected with the base stage of triode Q80 with resistance R578 by diode D198 successively, the base stage of triode Q80 is by resistance R435 ground connection, the grounded emitter of triode Q80 and being connected with the source electrode of metal-oxide-semiconductor Q33 by electric capacity C17, the collector electrode of triode Q80 is connected with the grid of metal-oxide-semiconductor Q33, the collector electrode of triode Q80 is connected with described supply voltage VCC by resistance R434.

As shown in figure 11, described just stage drive circuit is 2, is designated as the 1st first stage drive circuit and the 2nd just stage drive circuit respectively.1st first stage drive circuit is made up of resistance R442, resistance R443, resistance R698, resistance R715, resistance R447, diode D214 and triode Q36.2nd first stage drive circuit is made up of resistance R456, resistance R457, resistance R699, resistance R717, resistance R458, diode D215 and triode Q40.Syndeton explanation is carried out for the 1st first stage drive circuit, the collector electrode of triode Q36 is connected with one end of resistance R442, the other end of resistance R442 is as second input (CHANNEL0) of the 1st first stage drive circuit, the base stage of triode Q36 is connected with the negative electrode of diode D214 by resistance 698, the anode of D diode 214 is as the first input end (DRIVE1) of the 1st first stage drive circuit, the base stage of triode Q36 is by resistance R443 ground connection, the anode of diode D214 is by resistance R715 ground connection, the emitter of triode Q35 is by resistance R447 ground connection, the emitter of triode Q36 connects with the control end (DISC_01) of corresponding balancing circuitry.

In conjunction with shown in Figure 12 to Figure 14, described final stage controls comparison circuit, for the 3rd reference voltage and the 2nd reference voltage being compared with the sampling battery voltage of corresponding lithium battery respectively by its final stage comparison circuit, and exports one first final stage level signal; One second final stage level signal is exported according to all first final stage level signals by its final stage State-output circuit; Judge whether to export final stage drive singal to the balancing circuitry of correspondence according to the second final stage level signal and the first corresponding final stage level signal by its final driving circuit.

As shown in figure 12, described final stage comparison circuit is 2, is designated as the 1st final stage comparison circuit and the 2nd final stage comparison circuit respectively.1st final stage comparison circuit is made up of resistance R324 to R327, voltage comparator U85-A, voltage comparator U85-B, diode D80 and diode D81, and the 2nd final stage comparison circuit is made up of resistance R328 to R331, voltage comparator U86-A, voltage comparator U86-B, diode D82 and diode D83.Syndeton explanation is carried out for the 1st final stage comparison circuit, the normal phase input end of voltage comparator U85-B is connected with the 2nd reference voltage by resistance R324, the inverting input of voltage comparator U85-B is connected with described sampling battery voltage by resistance R326, the inverting input of voltage comparator U85-A is connected with the 3rd reference voltage by resistance R327, the normal phase input end of voltage comparator U85-A is connected with described sampling battery voltage by resistance R325, the output of voltage comparator U85-B is connected with the anode of diode D80, the negative electrode of diode D80 connects with the input (DRIVE31) of the corresponding of final stage State-output circuit and the first input end (DRIVE31) of corresponding final driving circuit, the output of voltage comparator U85-A is connected with the anode of diode D81, and the negative electrode of diode D81 is connected with the negative electrode of diode D80.

As shown in figure 13, described final stage State-output circuit comprises diode D148, resistance R421, diode D149, resistance R422, resistance R590, resistance R589, metal-oxide-semiconductor 85, electric capacity C19 and triode Q86.Diode D148 connects with resistance R421 formation 1 the 3rd series arm, one end of 3rd series arm connects with the output (DRIVE31) of corresponding final stage comparison circuit, the other end of the 3rd series arm is connected with the base stage of triode Q86, diode D149 connects with resistance R422 formation 1 the 4th series arm, one end of 4th series arm connects with the output (DRIVE32) of corresponding final stage comparison circuit, the other end of the 4th series arm is connected with the base stage of triode Q86, the base stage of triode Q86 is by resistance R590 ground connection, the grounded emitter of triode Q86 and being connected with the source electrode of metal-oxide-semiconductor Q85 by electric capacity C19, the source electrode of metal-oxide-semiconductor Q85 is connected with second input (CHANNEL03) of final driving circuit, the collector electrode of triode Q86 is connected with described supply voltage VCC by resistance R589 and is connected with the drain electrode of metal-oxide-semiconductor Q85, the collector electrode of triode Q86 is connected with the grid of metal-oxide-semiconductor Q85.

As shown in figure 14, described final driving circuit is 2, is designated as the 1st final driving circuit and the 2nd final driving circuit respectively.1st final driving circuit is made up of resistance R574, resistance R575, resistance R576, resistance R616, resistance R889, diode D161 and triode Q34, and the 2nd final driving circuit is made up of resistance R580, resistance R582, resistance R581, resistance R617, resistance R890, diode D185 and triode Q82.Syndeton explanation is carried out for the 1st final driving circuit, the collector electrode of triode Q34 is connected with one end of resistance R574, the other end of resistance R574 is as second input (CHANNEL03) of the 1st final driving circuit, the base stage of triode Q34 is connected with the negative electrode of diode D161 by resistance R616, the anode of diode D161 is as the first input end (DRIVE31) of the 1st final driving circuit, the base stage of triode Q34 is by resistance R575 ground connection, the anode of diode D161 is by resistance R889 ground connection, the emitter of triode Q34 is by resistance R576 ground connection, the emitter of triode Q34 connects with the control end (DISC_01) of corresponding balancing circuitry.

As shown in Figure 6, described balancing circuitry, for according to the 12nd elementary drive singal of correspondence or final stage drive singal, the positive pole controlling corresponding lithium battery is connected by power discharge resistance with negative pole, to make to carry out discharge process to the lithium battery of correspondence.Described balancing circuitry is 2, is designated as the 1st balancing circuitry and the 2nd balancing circuitry respectively.1st balancing circuitry is made up of photoelectrical coupler U9, resistance R82 (i.e. power discharge resistance), resistance R48, resistance R46 and metal-oxide-semiconductor Q6, and the 2nd balancing circuitry is made up of photoelectrical coupler U8, resistance R81 (i.e. another power discharge resistance), resistance R45, resistance R43 and metal-oxide-semiconductor Q5.Syndeton explanation is carried out for the 1st balancing circuitry, the drain electrode of metal-oxide-semiconductor Q6 is connected with the positive pole B1 of corresponding lithium battery by resistance R82, the source electrode of metal-oxide-semiconductor Q6 connects with the negative pole B-of corresponding lithium battery, the transistor emitter output of photoelectrical coupler U9 is connected with the grid of metal-oxide-semiconductor Q6, the transistor emitter output of photoelectrical coupler U9 is also connected with the negative pole B-of corresponding lithium battery by resistance R46, the transistor collector input of photoelectrical coupler U9 is connected with the positive pole B1 of corresponding lithium battery by resistance R48, the diode input of photoelectrical coupler U9 all connects with the output (DISC_01) of corresponding under-voltage protecting circuit and the output (DISC_01) of corresponding drive circuit.

Described supply voltage VCC, for providing operating voltage for sample circuit and under-voltage protecting circuit.

The operation principle of the present embodiment is as follows:

Arranging the 1st reference voltage is 1.5V, and the 2nd reference voltage is 1.8V, and the 3rd reference voltage is 2.1V.User also can as required, and add the quantity of reference voltage and arrange, as 1.5V, 1.65V, 1.8V, 1.95V, 2.1V, reference voltage is more, and precision is higher.

Lithium battery was ganged up row's pin and was connected with sample circuit, exported the voltage half that BATV (i.e. sampling battery voltage) is single lithium battery.

In under-voltage protecting circuit; BATV and 1.5V is compared; if BATV>1.5V; triode Q13 ends, and under-voltage protecting circuit and balancing circuitry disconnect, and do not process; if BATV≤1.5V; then by the control end ground connection of balancing circuitry, single lithium battery voltage is not processed lower than during 3.0V, thus protection lithium battery can not over-discharge can.

When BATV>1.5V, single lithium battery voltage processes, described in specific as follows according to the method for Approach by inchmeal:

First, determine the condition that balancing circuitry starts, the condition triggered is exactly that monomer lithium electricity battery pressure reduction exceeds higher limit, higher limit is chosen and is determined according to reference voltage value, as the 1st reference voltage selects 1.5V, the 2nd reference voltage selects 1.8V, illustrates that cell voltage does not process between 3.0-3.6V, but outside this voltage range, namely single lithium battery voltage difference will carry out discharge process higher than the lithium battery of 0.6V.The present embodiment has 1 primary control comparison circuit and 1 final stage to control comparison circuit, from entirety, is secondary comparison process, and the order of startup is the conditional decision according to power supply. specific as follows:

A. due to power supply order, first (principle of elementary comparison circuit is that lithium battery is pressed between 1.5-1.8V to start the 1st grade of control comparison circuit, DRIVEn low level output, otherwise high level output, n=1,2), the sampling battery voltage BATVn of single lithium battery can be analyzed whether between 1.5-1.8V (3.0-3.6V), if, elementary comparison circuit exports DRIVEn low level, otherwise DRIVEn exports high level, having 3 kinds of situation: situation 1:DRIVEn entirely is here high level (sampling battery voltage is all higher than 1.8V); Situation 2:DRIVEn is low level (sampling battery voltage is between 1.5-1.8V) entirely; Situation 3:DRIVEn has for low and high level entirely (sampling battery voltage have between 1.5-1.8V, also have higher than 1.8V's).

B. elementary first State-output circuit, it is whether the sampling battery voltage gathering single lithium battery has between 1.5-1.8V, if single lithium battery has 1 at least within the scope of this (DRIVEn has at least 1 to export as low level), STATE00 just can draw ground, output low level; Elementary second State-output circuit, sampling battery voltage has 1 at least higher than 1.8V (DRIVEn has at least 1 to export as high level), STATE01 just can export high level, 3 kinds of combinations can be obtained by elementary first State-output circuit and elementary second State-output circuit, combination 1 (STATE00:STATE01=00, the sampling battery voltage of single lithium battery is between 1.5-1.8V); Combination 2 (STATE00:STATE01=01, the sampling battery voltage of single lithium battery is existing also to be had higher than 1.8V's between 1.5-1.8V); Combination 3 (STATE00:STATE01=11, the sampling battery voltage of single lithium battery is entirely on 1.8V);

C. be input in primary control circuit 3 kinds of possible composite signals, if the situation of combination 1, whole circuit will not do Balance Treatment and (close metal-oxide-semiconductor Q33, metal-oxide-semiconductor Q35, CHANNEL0 no-output), also do not control comparison circuit to final stage to power (closing metal-oxide-semiconductor Q27, POWER00 no-output) simultaneously, make it lose efficacy.If the situation of combination 2: close final stage control comparison circuit and power (closing metal-oxide-semiconductor Q27, POWER00 no-output), open elementary drive circuitry (opening metal-oxide-semiconductor Q33, metal-oxide-semiconductor Q35, CHANNEL0 output drive signal).If the situation of combination 3: open final stage control comparison circuit and power (open metal-oxide-semiconductor Q27, POWER00 exports), close elementary drive circuitry (close metal-oxide-semiconductor Q33, metal-oxide-semiconductor Q35, CHANNEL0 export).

The principle that final stage controls comparison circuit and the 1st grade of control comparison circuit is similar, just a reference source voltage range is different, final stage is the higher limit of reference voltage, be equivalent to eliminate elementary first State-output circuit and primary control circuit, because battery voltage limit value is 4.2V, it directly can judge the cell voltage whether having the single lithium battery exceeding 4.2V in final stage comparison circuit, thus open balancing circuitry, final stage State-output circuit provides final driving circuit supply power voltage, and final driving circuit just can drive the single lithium battery of corresponding balancing circuitry to correspondence to discharge in conjunction with final stage comparison circuit.

Balancing circuitry adopts photoelectric coupler isolation to control, the control preventing the pressure reduction problem between lithium battery string (high voltage) and control circuit (low-voltage) from causing and safety problem.

From above-mentioned two embodiments, embodiment one only has one-level to control comparison circuit and 2 reference voltages, and precision is lower, and embodiment two has Two-stage control comparison circuit and 3 reference voltages, and precision comparatively embodiment one is high.Therefore, if the progression controlling comparison circuit is more, reference voltage is more, and precision is higher.

The utility model cost of manufacture is low, use simple, can arbitrarily combine, the artificial voltage difference standard that single lithium battery is set, under charging, electric discharge, leaving standstill 3 kinds of situations, real-time ensuring lithium battery balance coupling, improves the useful life of multi-series lithium battery, adds stability and the reliability of multi-series lithium battery.

For a person skilled in the art, according to technical scheme described above and design, other various corresponding change and distortion can be made, and all these change and distortion all should belong within the protection range of the utility model claim.

Claims

1. the balanced protection circuit of lithium battery, the quantity of described lithium battery is at least two, and all lithium batteries are connected in series, it is characterized in that, described balanced protection circuit comprises: all identical with the quantity of described lithium battery and the sample circuit, balancing circuitry, under-voltage protecting circuit, comparison circuit and the drive circuit that connect one to one with described lithium battery, one first reference voltage, one second reference voltage, a supply voltage and a State-output circuit;

2. the balanced protection circuit of lithium battery, the quantity of described lithium battery is at least two, and all lithium batteries are connected in series, it is characterized in that, described balanced protection circuit comprises: all identical with the quantity of described lithium battery and the sample circuit, balancing circuitry and the under-voltage protecting circuit that connect one to one with described lithium battery, at least one primary control comparison circuit, a final stage control comparison circuit, a reference voltage output circuit and a supply voltage;

……；

3. balanced protection circuit as claimed in claim 2, it is characterized in that, described sample circuit comprises the first to the 5th resistance and differential amplifier, the inverting input of differential amplifier is connected with the negative pole of corresponding lithium battery by the 3rd resistance, the normal phase input end of differential amplifier is connected with the positive pole of corresponding lithium battery by the 4th resistance, the normal phase input end of differential amplifier is also by the 5th grounding through resistance, the inverting input of differential amplifier is also by the first grounding through resistance, the inverting input of differential amplifier is also connected with the output of differential amplifier by the second resistance, the output of differential amplifier exports the sampling battery voltage of corresponding lithium battery.

4. balanced protection circuit as claimed in claim 2, it is characterized in that, described under-voltage protecting circuit comprises the 6th to the 9th resistance, operational amplifier and the first triode, the inverting input of operational amplifier is connected with the sampling battery voltage of corresponding lithium battery by the 6th resistance, the normal phase input end of operational amplifier is connected with the 1st reference voltage by the 7th resistance, the output of operational amplifier is connected with the base stage of the first triode by the 8th resistance, the output of operational amplifier is also by the 9th grounding through resistance, the grounded emitter of the first triode, the collector electrode of the first triode is connected with the control end of balancing circuitry.

5. balanced protection circuit as claimed in claim 2, it is characterized in that, described balancing circuitry comprises photoelectrical coupler, tenth to the 12 resistance and the first metal-oxide-semiconductor, the drain electrode of the first metal-oxide-semiconductor is connected with the positive pole of corresponding lithium battery by the 11 resistance, the source electrode of the first metal-oxide-semiconductor connects with the negative pole of corresponding lithium battery, the transistor emitter output of photoelectrical coupler is connected with the grid of the first metal-oxide-semiconductor, the transistor emitter output of photoelectrical coupler is also connected with the negative pole of corresponding lithium battery by the 12 resistance, the transistor collector input of photoelectrical coupler is connected with the positive pole of corresponding lithium battery by the 11 resistance, the diode input of photoelectrical coupler all connects with the output of corresponding under-voltage protecting circuit and the output of corresponding drive circuit.

6. balanced protection circuit as claimed in claim 2, it is characterized in that, described elementary comparison circuit comprises the 13 to the 16 resistance, first voltage comparator, second voltage comparator, first diode and the second diode, the normal phase input end of the first voltage comparator is connected with N reference voltage by the 14 resistance, the inverting input of the first voltage comparator is connected with described sampling battery voltage by the 13 resistance, the inverting input of the second voltage comparator is connected with N+1 reference voltage by the 16 resistance, the normal phase input end of the second voltage comparator is connected with described sampling battery voltage by the 15 resistance, the output of the first voltage comparator is connected with the anode of the first diode, the negative electrode of the first diode and the corresponding input of elementary first State-output circuit, the corresponding first input end of first stage drive circuit and the input of the correspondence of elementary second State-output circuit connect, the output of the second voltage comparator is connected with the anode of the second diode, and the negative electrode of the second diode is connected with the negative electrode of the first diode.

7. balanced protection circuit as claimed in claim 6, it is characterized in that, described elementary first State-output circuit comprises the first State-output electronic circuit identical with the quantity of lithium battery, each first State-output electronic circuit comprises the 17 resistance, 18 resistance and the second triode, the base stage of the second triode is connected with the output of corresponding elementary comparison circuit by the 18 resistance, the base stage of the second triode is also connected with described supply voltage by the 17 resistance, the grounded collector of the second triode, the emitter of the second triode is connected with the first input end of primary control circuit, the emitter of the second triode of one of them the first State-output electronic circuit is also connected with described supply voltage by 1 the 19 resistance,

8. balanced protection circuit as claimed in claim 2, it is characterized in that, described final stage comparison circuit comprises the 43 to the 46 resistance, 5th voltage comparator, 6th voltage comparator, 7th diode and the 8th diode, the normal phase input end of the 5th voltage comparator is connected with N+1 reference voltage by the 44 resistance, the inverting input of the 5th voltage comparator is connected with described sampling battery voltage by the 43 resistance, the inverting input of the 6th voltage comparator is connected with N+2 reference voltage by the 46 resistance, the normal phase input end of the 6th voltage comparator is connected with described sampling battery voltage by the 45 resistance, the output of the 5th voltage comparator is connected with the anode of the 7th diode, the negative electrode of the 7th diode connects with the corresponding input of final stage State-output circuit and the first input end of corresponding final driving circuit, the output of the 6th voltage comparator is connected with the anode of the 8th diode, and the negative electrode of the 8th diode is connected with the negative electrode of the 7th diode.

9. balanced protection circuit as claimed in claim 8, it is characterized in that, described final stage State-output circuit comprises nine diode identical with the quantity of lithium battery and the 43 resistance, 8th triode and the 44 to the 45 resistance, each the 9th diode forms a series arm with one the 43 corresponding resistant series, one end of each series arm connects with the output of corresponding final stage comparison circuit, the other end of each series arm is connected with the base stage of the 8th triode, the base stage of the 8th triode is by the 45 grounding through resistance, the grounded emitter of the 8th triode and being connected with the source electrode of the 5th metal-oxide-semiconductor by the 4th electric capacity, the source electrode of the 5th metal-oxide-semiconductor is connected with the second input of final driving circuit, the collector electrode of the 8th triode is connected with described supply voltage by the 44 resistance and is connected with the drain electrode of described 5th metal-oxide-semiconductor, the collector electrode of the 8th triode is connected with the grid of the 5th metal-oxide-semiconductor,