CN204668925U - There is the lithium battery protection circuit of overtemperature protection - Google Patents
There is the lithium battery protection circuit of overtemperature protection Download PDFInfo
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- CN204668925U CN204668925U CN201420795414.3U CN201420795414U CN204668925U CN 204668925 U CN204668925 U CN 204668925U CN 201420795414 U CN201420795414 U CN 201420795414U CN 204668925 U CN204668925 U CN 204668925U
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Abstract
The utility model discloses a kind of lithium battery protection circuit with overtemperature protection, comprise li-ion cell protection IC, charge and discharge protecting switching tube and lithium battery overheating protection circuit, lithium battery overheating protection circuit is used for carrying out overtemperature protection to lithium battery, it comprises temperature sensing circuit, overheated comparison circuit, fuse and second protection switch, and the temperature that temperature sensing circuit detects described charge and discharge protecting switching tube place detects voltage with output temperature; Overheated comparison circuit exports overheating detection signal when temperature detection voltage exceeds preset range; Fuse is serially connected with in the charging and discharging circuit of lithium battery, and described second protection switch series is connected between described fusible link and ground, and its control end is taken over hot detection signal and closed to blow a fuse according to during overheating detection signal.Compared with prior art, the utility model to make switching tube adstante febre, can cut off charging and discharging circuit in former li-ion cell protection fault in time, reminding user lithium battery fault.
Description
Technical field
The utility model relates to a kind of lithium battery protection circuit, especially designs the overtemperature protection of lithium battery.
Background technology
In recent years, PDA, digital camera, mobile phone, the increasing product such as portable audio device and bluetooth equipment adopts lithium battery as main power source, it is little that lithium battery has volume, energy density is high, memory-less effect, cycle life is high, high-voltage battery and the advantage such as self-discharge rate is low, with NI-G, Ni-MH battery is not quite alike, lithium battery must consider charging, fail safe during electric discharge, to prevent deterioration in characteristics. overcharging for lithium battery, over-discharge can, overcurrent and short-circuit protection are very important, because lithium ion battery energy density is high, therefore the fail safe guaranteeing battery is difficult to, under overcharged state, after battery temperature rises, energy is by surplus, so electrolyte decomposition and produce gas, because interior pressing rises and the danger that spontaneous combustion occurs or breaks, otherwise under over-discharge state, electrolyte causes battery behavior and durability deterioration because decomposing, thus reduces chargeable number of times, the protective circuit of lithium ion battery be exactly to guarantee such overcharge and discharge condition time fail safe, and prevent deterioration in characteristics.
The protective circuit of traditional lithium ion battery generally comprises surcharge protection (overvoltage protection) and transient discharge protection (under-voltage protection); the protective circuit of lithium battery is made up of li-ion cell protection IC and two power MOSFET; wherein li-ion cell protection IC monitors cell voltage, when have overcharge and discharge condition time control corresponding power MOSFET action to cut off charging and discharging circuit or charging and discharging circuit.But when power MOSFET failed shorted or li-ion cell protection IC fault to such an extent as to power MOSFET frequent movement time; lithium battery protection circuit cannot normally work; user is also difficult to place of pinpointing the problems, and damages even cause danger to make lithium battery may be in the state of overcharging for a long time.
Therefore, be badly in need of a kind of safe and reliable lithium battery protection circuit.
Utility model content
The purpose of this utility model is to provide a kind of lithium battery protection circuit with overtemperature protection, can detection power MOSFET fault, safe and reliable.
In order to realize there is object, the utility model discloses a kind of lithium battery protection circuit with overtemperature protection, comprise li-ion cell protection IC, charge and discharge protecting switching tube and lithium battery overheating protection circuit, described charge and discharge protecting switching tube is connected afterwards and is serially connected with the charging and discharging circuit of lithium battery, described li-ion cell protection IC controls described charge and discharge protecting switching tube and disconnects when lithium battery fault, described lithium battery overheating protection circuit is used for carrying out overtemperature protection to lithium battery, it comprises temperature sensing circuit, overheated comparison circuit, fuse and second protection switch, the temperature that described temperature sensing circuit detects described charge and discharge protecting switching tube place detects voltage with output temperature, the more described temperature detection voltage of described overheated comparison circuit and preset range also export overheating detection signal when described temperature detection voltage exceeds preset range, and when the temperature that described temperature sensing circuit detects is greater than preset temperature, described temperature detection voltage exceeds preset range, described fuse is serially connected with in the charging and discharging circuit of described lithium battery, overheating detection signal described in the control termination of described second protection switch, one end of fuse described in input termination, output head grounding, and according to described overheating detection signal closes.
Compared with prior art, the utility model near described charge and discharge protecting switching tube set temperature testing circuit to detect the temperature at described charge and discharge protecting switching tube place, when charge and discharge protecting switching tube burn short circuit or li-ion cell protection IC fault make charge and discharge protecting switching tube frequent movement time, described charge and discharge protecting switching tube sends amount of heat, temperature detection voltage is made to exceed preset range (being greater than or less than preset value), overheated comparison circuit exports overheating detection signal, second protection switch closes thereupon, one end ground short circuit of fuse is to blow a fuse, the charging and discharging circuit of lithium battery disconnects, the charging of available protecting lithium battery, can in time with reminding user lithium battery fault.
Preferably; described temperature sensing circuit comprises the first bleeder circuit; described first bleeder circuit comprises thermistor RN and resistance R2; be serially connected with after described thermistor RN connects with resistance R2 between a reference voltage and ground; described first bleeder circuit exports the first branch pressure voltage by the output between described resistance R2 and thermistor RN; and described thermistor RN closes on described charge and discharge protecting switching tube, described first branch pressure voltage is described temperature detection voltage.
Preferably, described lithium battery protection circuit also comprises the second bleeder circuit, described second bleeder circuit comprises resistance R3 and resistance R4, described resistance R3 and resistance R4 is serially connected with between a reference voltage and ground after connecting, and described second bleeder circuit exports the second branch pressure voltage by the output between described resistance R3 and resistance R4; Thermistor RN is negative temperature system thermistor, described overheated comparison circuit comprises comparator A1 and is connected to the feedback resistance R6 between the inverting input of described comparator A1 and output, the in-phase input end of described comparator A1 connects described second branch pressure voltage, first branch pressure voltage described in the anti-phase input termination of described comparator A1, controls the overheating detection signal that described comparator A1 exports high level when being greater than preset temperature with the temperature detected at thermistor RN.
Particularly, described temperature sensing circuit also comprises the first electric capacity C1 be serially connected with between described first bleeder circuit output and ground, and is serially connected with the second electric capacity C2 between the output of described second bleeder circuit and ground.
Preferably; described second protection switch comprises the first metal-oxide-semiconductor and resistance R5; the grid (G) of described first metal-oxide-semiconductor connects described overheating detection signal; drain electrode (D) connects one end of described fuse; source electrode (S) ground connection; described resistance R5 is connected between the grid (G) of described first metal-oxide-semiconductor and ground; conducting when receiving overheating detection signal to make described first metal-oxide-semiconductor; big current is flowed through, the blown fuse be connected with the first metal-oxide-semiconductor between the drain electrode (D) of the first metal-oxide-semiconductor and source electrode (S).
Particularly, the output of described overheated comparison circuit is connected with the grid (G) of the first metal-oxide-semiconductor with diode D1 by resistance R7.
Particularly, filter capacitor C5 is also serially connected with between the grid (G) of described first metal-oxide-semiconductor and ground.
Preferably, described lithium battery protection circuit also comprises lithium battery secondary voltage protective circuit, described lithium battery has multiple batteries battery core, described charge and discharge protecting switching tube comprises charge protection metal-oxide-semiconductor and discharge prevention metal-oxide-semiconductor, the charging control pin of described li-ion cell protection IC connects the control end of described charge protection metal-oxide-semiconductor and exceedes charge protection metal-oxide-semiconductor disconnection described in overvoltage threshold values time control system at the voltage of single battery battery core, the control of discharge pin of described li-ion cell protection IC connects the control end of described discharge prevention metal-oxide-semiconductor and disconnects lower than controlling described discharge prevention metal-oxide-semiconductor during under-voltage threshold values at the voltage of single battery battery core, described lithium battery secondary voltage protective circuit is used for carrying out secondary overvoltage protection to lithium battery, and it comprises voltage collection circuit and voltage comparator circuit, and described voltage collection circuit obtains the voltage of each battery battery core in each lithium battery, described voltage comparator circuit compares voltage and the preset voltage value of each battery battery core, and when the magnitude of voltage of arbitrary described battery battery core exceeds preset voltage value by output output overvoltage detection signal, described preset voltage value is greater than described overvoltage threshold values, the control end of described second protection switch connects the output of described voltage comparator circuit by diode D2, close according to described overvoltage detection signal to make described second protection switch.Compared with prior art; the utility model is provided with a kind of lithium battery secondary voltage protective circuit; for carrying out secondary overvoltage protection to lithium battery, not only can ensure when li-ion cell protection IC or two power MOSFET fault, the charging of available protecting lithium battery; prevent the many degree chargings of lithium battery to such an extent as to cause danger; safe and reliable, and when former li-ion cell protection lost efficacy, fusible link fuses; charging and discharging circuit open circuit, with reminding user lithium battery fault.
Particularly, described lithium battery has N batteries battery core, N be more than or equal to 2 integer, described voltage collection circuit comprises N-1 road voltage subtraction device, and the inverting input of voltage subtraction device described in N-1 road connects Section 2 saves described battery battery core positive pole to N respectively, the in-phase input end of voltage subtraction device described in N-1 road connects Section 1 saves described battery battery core positive pole to N-1 respectively, described in Yi Shi N-1 road, the output of voltage subtraction device exports the voltage of Section 2 to N batteries battery core respectively, and the voltage of first segment battery battery core equals the voltage of first segment battery battery core positive pole.
Particularly, described plurality of voltages subtracter comprises LM324 chip and subtracter peripheral circuit.
Particularly, described lithium battery has N batteries battery core, N be more than or equal to 2 integer, described voltage comparator circuit comprises N road voltage comparator, described in N road, the in-phase input end of voltage comparator connects the voltage of first segment to N batteries battery core, the reference voltage of the anti-phase input termination preset voltage value size of voltage comparator described in N road, described in N road, the output of voltage comparator is connected to the output of described voltage comparator circuit, to export the overvoltage detection signal of high level when the voltage of arbitrary described battery battery core is greater than preset voltage value.
Particularly, described voltage comparator circuit comprises LM339 chip and comparator peripheral circuit.
Accompanying drawing explanation
Fig. 1 is lithium battery protection circuit circuit diagram described in the utility model.
Fig. 2 is the partial circuit figure of voltage collection circuit described in the utility model.
Fig. 3 is the circuit diagram of follower described in the utility model.
Fig. 4 is the partial circuit figure of voltage comparator circuit described in the utility model.
Embodiment
By describing technology contents of the present utility model, structural feature in detail, realized object and effect, accompanying drawing is coordinated to be explained in detail below in conjunction with execution mode.
With reference to figure 1, the utility model discloses a kind of lithium battery protection circuit 100, comprise li-ion cell protection IC10, charge and discharge protecting switching tube and lithium battery overheating protection circuit, in the present embodiment, described charge and discharge protecting switching tube comprises charge protection metal-oxide-semiconductor Q1 and discharge prevention metal-oxide-semiconductor Q2, described charge protection metal-oxide-semiconductor Q1 and discharge prevention metal-oxide-semiconductor Q2 is serially connected with the charging and discharging circuit of lithium battery, described li-ion cell protection IC controls described charge protection metal-oxide-semiconductor Q1 or discharge prevention metal-oxide-semiconductor Q2 and disconnects when lithium battery fault, described lithium battery has N batteries battery core B1-BN, N be more than or equal to 2 integer.Described lithium battery overheating protection circuit is used for carrying out overtemperature protection to lithium battery; namely, when li-ion cell protection IC10, charge protection metal-oxide-semiconductor Q1 or discharge prevention metal-oxide-semiconductor Q2 fault are to make charge protection metal-oxide-semiconductor Q1 or discharge prevention metal-oxide-semiconductor Q2 send amount of heat, the charging and discharging circuit controlling lithium battery disconnects.
Continue with reference to figure 1, described lithium battery overheating protection circuit comprises temperature sensing circuit, overheated comparison circuit 16, fuse 13 and second protection switch 14, the temperature that described temperature sensing circuit detects described charge and discharge protecting switching tube place detects voltage with output temperature, and exports the temperature detection voltage exceeding preset range when the temperature detected is greater than preset temperature; The more described temperature detection voltage of described overheated comparison circuit 16 and preset range also export overheating detection signal when described temperature detection voltage exceeds preset range; The charging positive pole C+ of lithium battery described in described fuse 13 1 termination and electric discharge positive pole P+, the total positive pole B+ of another termination battery battery core; Overheating detection signal described in the control termination of described second protection switch 14, one end of fuse 13 described in input termination, output head grounding, and according to described overheating detection signal closes.Wherein, B-is total negative pole of battery battery core, and C-is charging negative pole, and P+ is load positive pole, and P-is load negative pole.
In the present embodiment, continue with reference to figure 1, described second protection switch 14 comprises the first metal-oxide-semiconductor Q3 and resistance R5, the grid (G) of described first metal-oxide-semiconductor Q3 connects described overheating detection signal, drain electrode (D) connects one end (discharge and recharge positive pole C+ or the total positive pole B+ of battery battery core) of described fuse 13, source electrode (S) ground connection, described resistance R5 is connected between the grid (G) of described first metal-oxide-semiconductor and ground, conducting when receiving overheating detection signal to make described first metal-oxide-semiconductor Q3, to make one end ground connection of fuse 13, being equivalent to fuse 13 is directly connected between discharge and recharge positive pole C+ and ground, charging and discharging circuit is shorted, fuse 13 fuses, the charging and discharging circuit of lithium battery disconnects.Wherein, the input that (D) can connect fuse 13 of draining also can connect the output of fuse 13.Certainly, described second protection switch 14 also can be made up of other switching tube, is not limited in the range of structures of above-mentioned metal-oxide-semiconductor Q3 composition.
In the present embodiment, described temperature sensing circuit comprises the first bleeder circuit, and described first bleeder circuit comprises thermistor RN and resistance R2, and described thermistor RN closes on described charge protection metal-oxide-semiconductor Q1 and discharge prevention metal-oxide-semiconductor Q2; Be serially connected with after described thermistor RN connects with resistance R2 between a reference voltage and ground, described first bleeder circuit exports the first branch pressure voltage U1 by the output B between described resistance R2 and thermistor RN, and described first branch pressure voltage is described temperature detection voltage.Two inputs of described overheated comparison circuit 16 connect output B and a predeterminated voltage of described first bleeder circuit respectively, more described first branch pressure voltage U1 and predeterminated voltage, and overheating detection signal (certainly, also can be set to export overheating detection signal when the second branch pressure voltage U2 is less than described first branch pressure voltage U1) is exported when described second branch pressure voltage U2 is greater than described first branch pressure voltage U1.
Preferably, continues with reference to figure 1, is also serially connected with filter capacitor C5 between the grid (G) of described first metal-oxide-semiconductor Q3 and ground.
Preferably, continue with reference to figure 1, described lithium battery protection circuit also comprises the second bleeder circuit, described second bleeder circuit comprises resistance R3 and resistance R4, described resistance R3 and resistance R4 is serially connected with between a reference voltage and ground after connecting, and described second bleeder circuit exports the second branch pressure voltage U2 by the output C between described resistance R3 and resistance R4; Thermistor RN is negative temperature system thermistor, described overheated comparison circuit 16 comprises comparator A1 and is connected to the feedback resistance R6 between the inverting input of described comparator A1 and output, the in-phase input end of described comparator A1 meets described second branch pressure voltage U2, first branch pressure voltage U1 described in the anti-phase input termination of described comparator A1, when being greater than preset temperature with the temperature detected at thermistor RN, first branch pressure voltage U1 is less than the second branch pressure voltage U2, and described comparator A1 exports the overheating detection signal of high level.Wherein, described comparator A1 is chip LM324.In the present embodiment, described first metal-oxide-semiconductor is N-channel MOS pipe.Wherein, described lithium battery protection circuit 100 also comprises the first electric capacity C1 between output B and ground being serially connected with described first bleeder circuit, and is serially connected with the second electric capacity C2 between the output C of described second bleeder circuit and ground.
Preferably, continue with reference to figure 1, the output of described overheated comparison circuit 16 is connected with the grid (G) of the first metal-oxide-semiconductor with diode D1 by resistance R7.
Continue with reference to figure 1, the charging control pin CO of described li-ion cell protection IC10 connects the control end of described charge protection metal-oxide-semiconductor Q1 and exceedes charge protection metal-oxide-semiconductor Q1 described in overvoltage threshold values time control system at the voltage of single battery battery core and disconnect, the control of discharge pin DO of described li-ion cell protection IC10 connects the control end of described discharge prevention metal-oxide-semiconductor Q2 and disconnects lower than controlling described discharge prevention metal-oxide-semiconductor Q2 during under-voltage threshold values at the voltage of single battery battery core, described lithium battery protection circuit 100 also comprises lithium battery secondary voltage protective circuit, described lithium battery secondary overvoltage protective circuit is used for carrying out second protection to lithium battery, namely at li-ion cell protection IC10, charge protection metal-oxide-semiconductor Q1, discharge prevention metal-oxide-semiconductor Q2 fault, the single battery battery core voltage of lithium battery disconnects the charging and discharging circuit of lithium battery when exceeding overvoltage threshold values.Wherein, described li-ion cell protection IC10 not only can carry out overvoltage and under-voltage protection, can also detect the magnitude of current of discharge and recharge by resistance RX and carry out overcurrent protection.In the present embodiment, overvoltage threshold values is 4.2V, and described under-voltage threshold values is 2.5V.
Continue with reference to figure 1, described lithium battery secondary voltage protective circuit comprises voltage collection circuit 11 and voltage comparator circuit 12, and described voltage collection circuit 11 obtains the voltage of each battery battery core B1-BN in described lithium battery; Described voltage comparator circuit 12 compares the voltage of each battery battery core B1-BN and the preset voltage value of 4.3V, and being exported the overvoltage detection signal of high level by output when the magnitude of voltage of arbitrary described battery battery core B1, B2 or BN exceeds 4.3V, described preset voltage value is greater than described overvoltage threshold values; The control end of described second protection switch 14 connects the output of described voltage comparator circuit 12 by diode D2; close according to described overvoltage detection signal to make described second protection switch 14; now one end ground connection of fuse 13; fuse 13 is directly connected between discharge and recharge positive pole C+ and ground; charging and discharging circuit is shorted; fuse 13 fuses, and the charging and discharging circuit of lithium battery disconnects.
It is noted that described preset voltage value, overvoltage threshold values are and the concrete numerical value of described under-voltage threshold values is in no way limited within the scope of above-mentioned 4.3V, 4.2V and 2.5V, technical staff can arrange required numerical values recited according to actual needs.With reference to figure 1 and Fig. 2, described voltage collection circuit 11 comprises N-1 road voltage subtraction device, described in N-1 road, voltage subtraction device connects the cathode voltage of N batteries battery core respectively, calculate the difference of Section 2 to the cathode voltage of cathode voltage joint last with it (Section 1 is to the N-1 joint) battery battery core of N batteries battery core to obtain the voltage of Section 2 to N batteries battery core, the voltage VB1 of first segment battery battery core B1 equals the cathode voltage SB1 of first segment battery battery core B1.
With reference to figure 2, illustrate that wherein Section 1 connects the voltage computational methods of battery battery core B1-B5 to the 5th: Fig. 2 gathers the four road voltage subtraction devices of Section 2 to the voltage of Section 5 battery battery core B2-B5, described 4 road voltage subtraction devices comprise four high guaily unit integrated circuit D1 and peripheral circuit thereof: four high guaily unit integrated circuit D1 is LM324 chip, 4 pin of four high guaily unit integrated circuit D1 meet reference voltage V CC by resistance R10, the 11 pin ground connection of four high guaily unit integrated circuit D1, resistance R41 (the first feedback resistance) is serially connected with between 1 pin (the first output) of four high guaily unit integrated circuit D1 and 2 pin (the first inverting input), 2 pin (the first inverting input) of four high guaily unit integrated circuit D1 connect the positive pole of battery battery core B2 to receive the cathode voltage SB2 of battery battery core B2 by resistance 11, 3 pin (the first in-phase input end) of four high guaily unit integrated circuit D1 connect the positive pole of battery battery core B3 to receive the cathode voltage SB3 of battery battery core B3 by resistance 21, 3 pin of four high guaily unit integrated circuit D1 are by resistance R31 ground connection, the i.e. cathode voltage SB2 of the anti-phase input termination battery battery core B2 of first via voltage subtraction device, in-phase input end meets the cathode voltage SB3 of battery battery core B3, four high guaily unit integrated circuit D1 calculates the difference of the cathode voltage SB3 of battery battery core B3 and the cathode voltage SB2 of battery battery core B2, with the voltage VB3 making 1 pin of four high guaily unit integrated circuit D1 (the first output) export battery B3.Resistance R42 (the second feedback resistance) is serially connected with between 7 pin (the second output) of four high guaily unit integrated circuit D1 and 6 pin (the second inverting input), 6 pin (the second inverting input) of four high guaily unit integrated circuit D1 connect the positive pole of battery battery core B1 to receive the cathode voltage SB1 of battery battery core B1 by resistance 12, 5 pin (the second in-phase input end) of four high guaily unit integrated circuit D1 connect the positive pole of battery battery core B2 to receive the cathode voltage SB2 of battery battery core B2 by resistance 22, 5 pin of four high guaily unit integrated circuit D1 are by resistance R32 ground connection, 7 pin (the second output) of four high guaily unit integrated circuit D1 export the voltage VB2 of battery B2.Resistance R43 (the 3rd feedback resistance) is serially connected with between 8 pin (the 3rd output) of four high guaily unit integrated circuit D1 and 9 pin (the 3rd inverting input), 9 pin (the 3rd inverting input) of four high guaily unit integrated circuit D1 connect the positive pole of battery battery core B4 to receive the cathode voltage SB4 of battery battery core B4 by resistance 13, 10 pin (the 3rd in-phase input end) of four high guaily unit integrated circuit D1 connect the positive pole of battery battery core B5 to receive the cathode voltage SB5 of battery battery core B5 by resistance 23, 10 pin of four high guaily unit integrated circuit D1 are by resistance R33 ground connection, 8 pin (the 3rd output) of four high guaily unit integrated circuit D1 export the voltage VB5 of battery B5.Resistance R44 (the 4th feedback resistance) is serially connected with between 14 pin (the 4th output) of four high guaily unit integrated circuit D1 and 13 pin (the 4th inverting input), 13 pin (the 4th inverting input) of four high guaily unit integrated circuit D1 connect the positive pole of battery battery core B3 to receive the cathode voltage SB3 of battery battery core B3 by resistance 14, 12 pin (the 4th in-phase input end) of four high guaily unit integrated circuit D1 connect the positive pole of battery battery core B4 to receive the cathode voltage SB4 of battery battery core B4 by resistance 24, 12 pin of four high guaily unit integrated circuit D1 are by resistance R34 ground connection, 14 pin (the 4th output) of four high guaily unit integrated circuit D1 export the voltage VB4 of battery B4.The voltage VB4 of first segment battery battery core B1 equals the cathode voltage SB4 of first segment battery battery core B1.
Preferably, is also serially connected with filter capacitor C41 between 1 pin of described four high guaily unit integrated circuit D1 and 2 pin, is also serially connected with filter capacitor C10 between 4 pin and ground, is also serially connected with filter capacitor C42 between 6 pin and 7 pin, is also serially connected with filter capacitor C43 between 8 pin and 9 pin, is also serially connected with filter capacitor C44 between 13 pin and 14 pin.
Preferably, described voltage collection circuit 11 also comprises N road follower, the input of N road follower connects the positive pole of N batteries battery core respectively, export termination N-1 road voltage subtraction device, for the cathode voltage SB1-SBN to gather N batteries battery core, and the cathode voltage SB1-SBN of N batteries battery core is delivered to N-1 road voltage subtraction device.With reference to figure 3, for Section 1 is to No. four followers 15 corresponding to Section 4 battery battery core, gather the voltage of battery battery core B1-B4 end respectively to obtain voltage SB1-SB4.No. four followers 15 comprise four high guaily unit integrated circuit D3 and peripheral circuit thereof, and the model of four high guaily unit integrated circuit D3 is LM324.
With reference to figure 1 and 3, described voltage comparator circuit 12 comprises N road voltage comparator, whether the voltage that voltage comparator described in N road compares N batteries battery core B1-BN respectively exceeds preset voltage value, if then export the overvoltage detection signal of high level, the overvoltage detection signal conducting of described first metal-oxide-semiconductor Q3 foundation high level is to make fuse 13 circuit fusing, and the charging and discharging circuit of lithium battery disconnects.
With reference to figure 4, illustrate that wherein Section 1 connects the voltage compare method of battery battery core B1-B4 to the 4th: be 4 road comparators in Fig. 4, comprise four road voltage comparator D2 and peripheral circuits thereof, four road voltage comparator D2 are chip LM339, 3 pin of four road voltage comparator D2 meet VCC by R51, 12 pin ground connection, inverting input (4 pin of four road voltage comparator circuits, 6 pin, 8 pin and 10 pin) respectively by resistance R52, R53, R54 and R55 connects the reference voltage of 4.3V (preset voltage value), in-phase input end (5 pin of four road voltage comparator circuits, 7 pin, 9 pin and 11 pin) respectively by resistance R61, R62, R63 and R64 meets the voltage VB1 of first segment battery battery core, the voltage VB2 of second section battery battery core, 1 pin (the second output) of the voltage VB3 of the 3rd batteries battery core and the voltage VB4 of the 4th batteries battery core, four road voltage comparator D2, 2 pin (the first output), 13 pin (the 4th output), 14 pin (the 3rd output) connect A point respectively, export the comparative result of the reference voltage of VB1-VB4 and 4.3V respectively, at arbitrary voltage VB1, VB2, when VB3 or VB4 is greater than 4.3V (preset voltage value), A point exports the overvoltage detection signal of high level.
Preferably, is also serially connected with filter capacitor C61 between 5 pin of described four road voltage comparator D2 and ground, is also serially connected with filter capacitor C62 between 7 pin and ground, is also serially connected with filter capacitor C63 between 9 pin and ground, is also serially connected with filter capacitor C64 between 11 pin and ground.
Wherein, N-1 road voltage subtraction device and N road voltage comparator also can be the subtracter and voltage comparator that are made up of other chips and peripheral circuit, are not limited in above-mentioned scope.
With reference to figure 1; the course of work of the present utility model is described; when lithium cell charging, li-ion cell protection IC works, and detects the voltage and current of every batteries battery core in real time; and after lithium battery is full of electricity; li-ion cell protection IC detects that the voltage of battery battery core arrives the charging control pin CO output low level of 4.2V, li-ion cell protection IC, the drain electrode (D) of charge protection metal-oxide-semiconductor Q1 and source electrode (S) open circuit; charging and discharging lithium battery loop disconnects, and lithium battery is filled electricity.
If when the charge protection metal-oxide-semiconductor Q1 of lithium battery or discharge prevention metal-oxide-semiconductor Q2 is burnt open circuit or other faults is occurred, charge protection metal-oxide-semiconductor Q1 or discharge prevention metal-oxide-semiconductor Q2 can generate heat because of fault, thermistor RN detects the voltage when heat exceeds preset value and drops to preset voltage value (the second branch pressure voltage U2) once, therefore the first branch pressure voltage U1 is less than the second branch pressure voltage U2, comparator A1 exports the overheating detection signal of high level, the drain electrode (D) of the first metal-oxide-semiconductor and source electrode (S) short circuit, fuse 13 is serially connected with between charging end positive pole C+ and ground, fuse 13 fusing is burnt, charging and discharging circuit disconnects.
If the charge protection metal-oxide-semiconductor Q1 fault of lithium battery or li-ion cell protection IC fault make charging control pin, CO exports high level always; because charge protection metal-oxide-semiconductor Q1 can not disconnect when the voltage of battery battery core exceeds 4.2V; therefore battery battery core continues charging; when the voltage of battery battery core is greater than 4.3V; voltage comparator circuit 12 exports the overvoltage detection signal of high level by A point; the drain electrode (D) of the first metal-oxide-semiconductor and source electrode (S) short circuit; fuse 13 is serially connected with between charging end positive pole C+ and ground; fuse 13 fusing is burnt, and charging and discharging circuit disconnects.
Preferably, in order to timely reminding user, also has warning circuit in described lithium battery secondary voltage protective circuit, and described warning circuit can be connected to buzzer between A point and ground and/or light-emitting diode, is used for li-ion cell protection fault for reminding.
Wherein, total positive pole B+ of voltage reference circuit 20 one end lithium battery, for providing corresponding reference voltage for lithium battery secondary voltage protective circuit, thus powers to lithium battery secondary voltage protective circuit.
Above disclosedly be only preferred embodiment of the present utility model, certainly can not limit the interest field of the utility model with this, therefore according to the equivalent variations that the utility model claim is done, still belong to the scope that the utility model is contained.
Claims (10)
1. one kind has the lithium battery protection circuit of overtemperature protection; comprise li-ion cell protection IC and charge and discharge protecting switching tube; described charge and discharge protecting switching tube is serially connected with the charging and discharging circuit of lithium battery; described li-ion cell protection IC controls described charge and discharge protecting switching tube and disconnects when lithium battery fault; it is characterized in that; also comprising lithium battery overheating protection circuit, for carrying out overtemperature protection to lithium battery, comprising:
Temperature sensing circuit, the temperature detecting described charge and discharge protecting switching tube place detects voltage with output temperature;
Overheated comparison circuit, the more described temperature detection voltage of described overheated comparison circuit and preset range also export overheating detection signal when described temperature detection voltage exceeds preset range, and when the temperature that described temperature sensing circuit detects is greater than preset temperature, described temperature detection voltage exceeds preset range;
Fuse, is serially connected with in the charging and discharging circuit of described lithium battery;
Second protection switch, overheating detection signal described in the control termination of described second protection switch, one end of fuse described in input termination, output head grounding, and according to described overheating detection signal closes.
2. there is the lithium battery protection circuit of overtemperature protection as claimed in claim 1; it is characterized in that; described temperature sensing circuit comprises the first bleeder circuit; described first bleeder circuit comprises thermistor RN and resistance R2; be serially connected with after described thermistor RN connects with resistance R2 between a reference voltage and ground; described first bleeder circuit exports the first branch pressure voltage by the output between described resistance R2 and thermistor RN; and described thermistor RN closes on described charge and discharge protecting switching tube, described first branch pressure voltage is described temperature detection voltage.
3. there is the lithium battery protection circuit of overtemperature protection as claimed in claim 2, it is characterized in that, also comprise the second bleeder circuit, described second bleeder circuit comprises resistance R3 and resistance R4, described resistance R3 and resistance R4 is serially connected with between a reference voltage and ground after connecting, and described second bleeder circuit exports the second branch pressure voltage by the output between described resistance R3 and resistance R4; Thermistor RN is negative temperature system thermistor, described overheated comparison circuit comprises comparator A1 and is connected to the feedback resistance R6 between the inverting input of described comparator A1 and output, the in-phase input end of described comparator A1 connects described second branch pressure voltage, first branch pressure voltage described in the anti-phase input termination of described comparator A1, controls the overheating detection signal that described comparator A1 exports high level when being greater than preset temperature with the temperature detected at thermistor RN.
4. there is the lithium battery protection circuit of overtemperature protection as claimed in claim 3; it is characterized in that; described temperature sensing circuit also comprises the first electric capacity C1 be serially connected with between described first bleeder circuit output and ground, and is serially connected with the second electric capacity C2 between the output of described second bleeder circuit and ground.
5. there is the lithium battery protection circuit of overtemperature protection as claimed in claim 1; it is characterized in that; described second protection switch comprises the first metal-oxide-semiconductor and resistance R5; the grid (G) of described first metal-oxide-semiconductor connects described overheating detection signal; drain electrode (D) connects one end of described fuse; source electrode (S) ground connection, described resistance R5 is connected between the grid (G) of described first metal-oxide-semiconductor and ground, conducting when receiving overheating detection signal to make described first metal-oxide-semiconductor.
6. have the lithium battery protection circuit of overtemperature protection as claimed in claim 5, it is characterized in that, the output of described overheated comparison circuit is connected with the grid (G) of the first metal-oxide-semiconductor with diode D1 by resistance R7.
7. there is the lithium battery protection circuit of overtemperature protection as claimed in claim 5, it is characterized in that, between the grid (G) of described first metal-oxide-semiconductor and ground, be also serially connected with filter capacitor C5.
8. there is the lithium battery protection circuit of overtemperature protection as claimed in claim 1, it is characterized in that, also comprise lithium battery secondary voltage protective circuit, described lithium battery has multiple batteries battery core, described charge and discharge protecting switching tube comprises charge protection metal-oxide-semiconductor and discharge prevention metal-oxide-semiconductor, the charging control pin of described li-ion cell protection IC connects the control end of described charge protection metal-oxide-semiconductor and exceedes charge protection metal-oxide-semiconductor disconnection described in overvoltage threshold values time control system at the voltage of single battery battery core, the control of discharge pin of described li-ion cell protection IC connects the control end of described discharge prevention metal-oxide-semiconductor and disconnects lower than controlling described discharge prevention metal-oxide-semiconductor during under-voltage threshold values at the voltage of single battery battery core, described lithium battery secondary voltage protective circuit is used for carrying out secondary overvoltage protection to lithium battery, and it comprises:
Voltage collection circuit, obtains the voltage of each battery battery core in each lithium battery;
Voltage comparator circuit, compares voltage and the preset voltage value of each battery battery core, and when the magnitude of voltage of arbitrary described battery battery core exceeds preset voltage value by output output overvoltage detection signal, described preset voltage value is greater than described overvoltage threshold values;
The control end of described second protection switch connects the output of described voltage comparator circuit by diode D2, close according to described overvoltage detection signal to make described second protection switch.
9. there is the lithium battery protection circuit of overtemperature protection as claimed in claim 8, it is characterized in that, described lithium battery has N batteries battery core, N be more than or equal to 2 integer, described voltage collection circuit comprises N-1 road voltage subtraction device, and the inverting input of voltage subtraction device described in N-1 road connects Section 2 saves described battery battery core positive pole to N respectively, the in-phase input end of voltage subtraction device described in N-1 road connects Section 1 saves described battery battery core positive pole to N-1 respectively, described in Yi Shi N-1 road, the output of voltage subtraction device exports the voltage of Section 2 to N batteries battery core respectively, and the voltage of first segment battery battery core equals the voltage of first segment battery battery core positive pole.
10. there is the lithium battery protection circuit of overtemperature protection as claimed in claim 8, it is characterized in that, described lithium battery has N batteries battery core, N be more than or equal to 2 integer, described voltage comparator circuit comprises N road voltage comparator, described in N road, the in-phase input end of voltage comparator connects the voltage of first segment to N batteries battery core, the reference voltage of the anti-phase input termination preset voltage value size of voltage comparator described in N road, described in N road, the output of voltage comparator is connected to the output of described voltage comparator circuit, to export the overvoltage detection signal of high level when the voltage of arbitrary described battery battery core is greater than preset voltage value.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420795414.3U CN204668925U (en) | 2014-12-15 | 2014-12-15 | There is the lithium battery protection circuit of overtemperature protection |
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| CN201420795414.3U CN204668925U (en) | 2014-12-15 | 2014-12-15 | There is the lithium battery protection circuit of overtemperature protection |
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| CN204668925U true CN204668925U (en) | 2015-09-23 |
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| CN201420795414.3U Expired - Fee Related CN204668925U (en) | 2014-12-15 | 2014-12-15 | There is the lithium battery protection circuit of overtemperature protection |
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| CN (1) | CN204668925U (en) |
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