Multi-charging protection circuit of lithium battery

Abstract

The utility model relates to a multi-charging protection circuit of a lithium battery. The multi-charging protection circuit comprises a fuse, a charging control switch module, a discharge control switch module, a battery charging and discharging management module, a temperature sensor and a charging counting acquisition module, the fuse is electrically connected with one end of the charging control switch module and one end of the discharge control switch module, and the other end of the discharge control switch module is grounded; the battery charging and discharging management module is respectively connected with the charging control switch module, the discharge control switch module, the temperature sensor and the charging counting acquisition module; according to the utility model, the temperature of the lithium battery acquired by the temperature sensor is acquired, and the on-off of the charging control switch module is controlled according to the temperature, so that the charging on-off of the lithium battery is controlled, and potential safety hazards such as battery combustion caused by overhigh temperature of the battery in the charging process of the lithium battery are prevented; and meanwhile, the current discharge control switch module is arranged to discharge the instantaneous large current, so that the instantaneous overlarge current is prevented from damaging electrical components.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium battery charging control technical field, concretely relates to a multiple charging protection circuit of lithium battery. BACKGROUND

[0002] Now lithium battery has been widely used in various 3C consumer electronic products, and the protection of lithium battery is usually taken in the form of pure IC \ MOS protection circuit when cooperating with the whole machine product, which only has the functions of overcharge, overdischarge, overcurrent and short circuit, and only protects the service life of lithium battery. However, in the actual application scene, it is also necessary to monitor the real-time remaining capacity, battery temperature, actual use frequency and fault condition of the battery at any time, and the user needs to obtain these parameters of the battery to further measure the use condition of the battery and ensure the safety of the battery. However, the existing lithium battery protection circuit does not have this function. UTILITY MODEL CONTENTS

[0003] In order to solve the technical problems that the existing technology cannot protect the charging according to the battery temperature during charging, the utility model provides a multiple charging protection circuit of lithium battery.

[0004] The technical scheme for solving the above technical problems of the utility model is as follows:

[0005] A multiple charging protection circuit of lithium battery, comprising a fuse, a charging control switch module, a discharge control switch module, a battery charging and discharging management module, a temperature sensor, a charging count acquisition module, a first charging connection end and a second charging connection end; the first charging connection end is used for connecting the positive electrode of the output end of a charging device, and the second charging connection end is used for connecting the negative electrode of the output end of the charging device;

[0006] One end of the fuse is electrically connected with the first charging connection end, and the other end of the fuse is electrically connected with one end of the charging control switch module and one end of the discharge control switch module respectively, the other end of the discharge control switch module is grounded, and the other end of the charging control switch module is used for connecting the positive electrode of a lithium battery; one end of the charging count acquisition module is electrically connected with the second charging connection end, and the other end of the charging count acquisition module is grounded, and the other end of the charging count acquisition module is used for connecting the negative electrode of the lithium battery; wherein the lithium battery comprises a plurality of electric cores connected in series;

[0007] The output end of the temperature sensor is electrically connected with the temperature data input end of the battery charging and discharging management module, the charging end voltage measurement input end of the battery charging and discharging management module is used for connecting the anode of the lithium battery, the battery end voltage measurement input end of the battery charging and discharging management module is used for connecting between two adjacent battery cells, the driving output end of the battery charging and discharging management module is respectively electrically connected with the controlled end of the charging control switch module and the controlled end of the discharge control switch module, and the two coulomb counting access ends of the battery charging and discharging management module are respectively electrically connected with the two ends of the charging counting acquisition module.

[0008] The battery charging and discharging management module can control the on-off of the charging control switch module according to the temperature of the lithium battery collected by the temperature sensor, so that the charging on-off of the lithium battery is controlled, and the safety hidden danger, such as battery combustion, caused by the too high battery temperature of the lithium battery during the charging process is prevented.

[0009] On the basis of the above technical scheme, the utility model still can make improvement as follows.

[0010] Further, the charging control switch module comprises a first MOS tube and a second MOS tube, the drain of the first MOS tube is electrically connected with the drain of the second MOS tube, the source of the first MOS tube is electrically connected with the other end of the fuse, the source of the second MOS tube is used for connecting the anode of the lithium battery, and the driving output end of the battery charging and discharging management module is respectively electrically connected with the gate of the first MOS tube and the gate of the second MOS tube.

[0011] The beneficial effect of the above further scheme is that the on-off control of charging is realized by two MOS tubes, and only when the two MOS tubes are simultaneously turned on, the whole charging control switch module is turned on, so that the safety control ability of the charging and discharging on-off control is improved.

[0012] Further, the charging control switch module further comprises a first resistor, a second resistor, a first bidirectional voltage stabilizing diode and a second bidirectional voltage stabilizing diode; one end of the first resistor is electrically connected with the gate of the first MOS tube, one end of the second resistor is electrically connected with the gate of the second MOS tube, the drive output end of the battery charging and discharging management module is electrically connected with the other end of the first resistor and the other end of the second resistor respectively; one end of the first bidirectional voltage stabilizing diode is electrically connected with the source of the first MOS tube, the other end of the first bidirectional voltage stabilizing diode is electrically connected with the other end of the first resistor; one end of the second bidirectional voltage stabilizing diode is electrically connected with the source of the second MOS tube, the other end of the second bidirectional voltage stabilizing diode is electrically connected with the other end of the second resistor.

[0013] The beneficial effect of the above further scheme is that the voltage stability between the source and the gate of the MOS tube can be improved by connecting the bidirectional voltage stabilizing diode between the source and the gate of the two MOS tubes.

[0014] Further, the battery charging and discharging management module comprises a battery charging and discharging management chip, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a ninth resistor, the model of the battery charging and discharging management chip is BQ28Z610, the drive output end of the battery charging and discharging management chip comprises a first drive output end and a second drive output end;

[0015] One end of the third resistor is electrically connected with the other end of the fuse, the other end of the third resistor is electrically connected with one end of the fourth resistor, the other end of the fourth resistor is electrically connected with the first drive output end, one end of the fourth resistor is electrically connected with the gate of the first MOS tube and the controlled end of the discharge control switch module respectively;

[0016] One end of the fifth resistor is used for electrically connecting with the positive pole of the lithium battery, the other end of the fifth resistor is electrically connected with one end of the sixth resistor, the other end of the sixth resistor is electrically connected with the second drive output end, one end of the sixth resistor is electrically connected with the gate of the second MOS tube;

[0017] One end of the seventh resistor is electrically connected with the battery end voltage measurement input end of the battery charging and discharging management chip, the other end of the seventh resistor is used for connecting between two adjacent battery cells; one end of the eighth resistor is electrically connected with the other end of the fuse, the other end of the eighth resistor is electrically connected with the sensing input end of the battery charging and discharging management chip; one end of the ninth resistor is used for connecting the positive pole of the lithium battery, the other end of the ninth resistor is electrically connected with the charging end voltage measurement input end of the battery charging and discharging management chip.

[0018] The beneficial effect of the further scheme is that the BQ28Z610 battery charge and discharge management chip provides a battery pack-based integrated solution with a flash programmable custom reduced instruction set CPU (RISC), security protection and authentication function, which is suitable for series lithium ion and lithium polymer battery packs, and improves the convenience of battery charge and discharge management.

[0019] Further, the discharge control switch module comprises a transistor and a tenth resistor, an emitter of the transistor is electrically connected with the other end of the fuse, a collector of the transistor is electrically connected with one end of the tenth resistor, the other end of the tenth resistor is grounded, and a base of the transistor is electrically connected with one end of the fourth resistor.

[0020] The beneficial effect of the further scheme is that the discharge control switch module comprises a transistor and a tenth resistor, an emitter of the transistor is electrically connected with the other end of the fuse, a collector of the transistor is electrically connected with one end of the tenth resistor, the other end of the tenth resistor is grounded, and a base of the transistor is electrically connected with one end of the fourth resistor.

[0021] Further, the charge count acquisition module comprises an eleventh resistor, a twelfth resistor and a thirteenth resistor, one end of the eleventh resistor is electrically connected with one coulomb count access end of the battery charge and discharge management chip, the other end of the eleventh resistor is electrically connected with one end of the thirteenth resistor, one end of the thirteenth resistor is electrically connected with the second charge connection end, the other end of the thirteenth resistor is grounded, and the other end of the thirteenth resistor is used for connecting the negative electrode of the lithium battery; one end of the twelfth resistor is electrically connected with another coulomb count access end of the battery charge and discharge management chip, and the other end of the twelfth resistor is electrically connected with the other end of the thirteenth resistor.

[0022] Further, the charge count acquisition module further comprises a first capacitor, a second capacitor and a third capacitor, one end of the first capacitor is electrically connected with one coulomb count access end of the battery charge and discharge management chip, the other end of the first capacitor is grounded, one end of the second capacitor is electrically connected with another coulomb count access end of the battery charge and discharge management chip, and the other end of the second capacitor is grounded; one end of the third capacitor is electrically connected with one coulomb count access end of the battery charge and discharge management chip, and the other end of the third capacitor is electrically connected with another coulomb count access end of the battery charge and discharge management chip.

[0023] The beneficial effect of the further scheme is that the capacitor is connected between the two coulomb counting access ends of the battery charge and discharge management chip and the ground wire, thereby filtering the noise of each coulomb counting access end to the ground; meanwhile, the capacitor is connected between the two coulomb counting access ends, thereby filtering the noise between the two coulomb counting access ends of the battery charge and discharge management chip, so as to improve the accuracy and stability of the coulomb counting.

[0024] Further, the temperature sensor is a thermistor, one end of the thermistor is electrically connected with the temperature data input end of the battery charge and discharge management chip, and the other end of the thermistor is grounded.

[0025] Further, the external output module comprises a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a first unidirectional voltage stabilizing diode and a second unidirectional voltage stabilizing diode.

[0026] One end of the thirteenth resistor is electrically connected with the serial clock end of the battery charge and discharge management chip, the other end of the thirteenth resistor is electrically connected with one end of the fifteenth resistor and the negative electrode of the second unidirectional voltage stabilizing diode respectively, the other end of the fifteenth resistor is used for connecting the serial clock end of the external signal processing device, and the positive electrode of the second unidirectional voltage stabilizing diode is electrically connected with the second charging connection end.

[0027] One end of the fourteenth resistor is electrically connected with the serial data end of the battery charge and discharge management chip, the other end of the fourteenth resistor is electrically connected with one end of the sixteenth resistor and the negative electrode of the first unidirectional voltage stabilizing diode respectively, the other end of the sixteenth resistor is used for connecting the serial data end of the external signal processing device, and the positive electrode of the first unidirectional voltage stabilizing diode is electrically connected with the second charging connection end.

[0028] Further, the fuse is a safety fuse, the rated current of the safety fuse is 10A, and the rated voltage of the safety fuse is 24V.

[0029] The beneficial effect of the further scheme is that when the charging current is too large, the safety fuse is fused to cut off the charging circuit, thereby ensuring the safety of the charging circuit and the battery. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the utility model;

[0031] Figure 2 It is a circuit principle diagram of the charging control switch module;

[0032] Figure 3 It is a circuit principle diagram of the utility model. DETAILED DESCRIPTION

[0033] The principles and characteristics of the present application are described below in conjunction with the accompanying drawings, which are provided only for explanation of the present application and are not intended to limit the scope of the present application.

[0034] As shown in Figure 1 The present embodiment provides a multiple charging protection circuit for lithium battery, a fuse, a charging control switch module, a discharge control switch module, a battery charging and discharging management module, a temperature sensor, a charging count collection module, a first charging connection end PA and a second charging connection end PN; the first charging connection end PA is used for connecting the positive pole of the output end of a charging device, and the second charging connection end PN is used for connecting the negative pole of the output end of the charging device;

[0035] One end of the fuse is electrically connected with the first charging connection end PA, and the other end of the fuse is electrically connected with one end of the charging control switch module and one end of the discharge control switch module respectively, the other end of the discharge control switch module is grounded, and the other end of the charging control switch module is used for connecting the positive pole of the lithium battery; one end of the charging count collection module is electrically connected with the second charging connection end PN, and the other end of the charging count collection module is grounded, and the other end of the charging count collection module is used for connecting the negative pole of the lithium battery; wherein the lithium battery comprises a plurality of electric cores connected in series;

[0036] The output end of the temperature sensor is electrically connected with the temperature data input end of the battery charging and discharging management module, the charging end voltage measurement input end of the battery charging and discharging management module is used for connecting the positive pole of the lithium battery, the battery end voltage measurement input end of the battery charging and discharging management module is used for connecting between two adjacent electric cores, and the drive output end of the battery charging and discharging management module is electrically connected with the controlled end of the charging control switch module and the controlled end of the discharge control switch module respectively; the two coulomb count access ends of the battery charging and discharging management module are electrically connected with the two ends of the charging count collection module respectively. If the lithium battery comprises two electric cores connected in series, the two electric cores are a first electric core and a second electric core respectively, the positive pole of the second electric core is electrically connected with the negative pole of the first electric core, the negative pole of the second electric core is the negative pole of the lithium battery, and the positive pole of the first electric core is the positive pole of the lithium battery. The battery end voltage measurement input end of the battery charging and discharging management module is electrically connected with the positive pole of the second electric core.

[0037] The battery charging and discharging management module acquires the temperature of the lithium battery collected by the temperature sensor, and controls the on-off of the charging control switch module according to the temperature, so as to control the on-off of the lithium battery, and prevent the lithium battery from catching fire due to high temperature during charging. Meanwhile, the discharge control switch module is grounded under the control of the battery charging and discharging management module, so as to facilitate the discharge of the charging current and prevent the instantaneous overcurrent from damaging the electrical components.

[0038] As shown in Figure 2 , the charging control switch module comprises a first MOS tube Q1 and a second MOS tube Q2, the drain of the first MOS tube Q1 is electrically connected with the drain of the second MOS tube Q2, the source of the first MOS tube Q1 is electrically connected with the other end of the fuse, the source of the second MOS tube Q2 is used for connecting the positive electrode of the lithium battery, and the driving output end of the battery charging and discharging management module is electrically connected with the gate of the first MOS tube Q1 and the gate of the second MOS tube Q2 respectively. The on-off control of charging is realized by two MOS tubes, and the whole charging control switch module is only turned on when the two MOS tubes are turned on at the same time, so as to improve the safety control ability of the charging and discharging on-off control.

[0039] The charging control switch module further comprises a first resistor R1, a second resistor R2, a first bidirectional voltage stabilizing diode D1 and a second bidirectional voltage stabilizing diode D2; one end of the first resistor R1 is electrically connected with the gate of the first MOS tube Q1, one end of the second resistor R2 is electrically connected with the gate of the second MOS tube Q2, and the driving output end of the battery charging and discharging management module is electrically connected with the other end of the first resistor R1 and the other end of the second resistor R2 respectively; one end of the first bidirectional voltage stabilizing diode D1 is electrically connected with the source of the first MOS tube Q1, and the other end of the first bidirectional voltage stabilizing diode D1 is electrically connected with the other end of the first resistor R1; one end of the second bidirectional voltage stabilizing diode D2 is electrically connected with the source of the second MOS tube Q2, and the other end of the second bidirectional voltage stabilizing diode D2 is electrically connected with the other end of the second resistor R2. By connecting the bidirectional voltage stabilizing diode D2 between the source and the gate of the two MOS tubes, the voltage stability between the source and the gate of the MOS tube can be improved.

[0040] As shown in Figure 3 , the charging control switch module can select a MOS tube integrated chip U2 with the specification of PAN1220Q / CSP-10, the internal circuit of the MOS tube integrated chip U2 is the circuit structure shown in Figure 2 , the S1 pin of the MOS tube integrated chip U2 is connected with the source of the first MOS tube Q1 in Figure 2 , and the S2 pin of the MOS tube integrated chip U2 is connected with the source of the second MOS tube Q2 in Figure 2The source of the second MOS Q2 in the figure.

[0041] In some embodiments, the battery charging and discharging management module includes a battery charging and discharging management chip U2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9. The model of the battery charging and discharging management chip U2 is BQ28Z610. The driving output end of the battery charging and discharging management chip U2 includes a first driving output end DSG and a second driving output end CHG. The resistance values of the third resistor R3 and the fifth resistor R5 are both 10 megaohms. The resistance values of the fourth resistor R4 and the sixth resistor R6 are both 5.1 kiloohms.

[0042] One end of the third resistor R3 is electrically connected to the other end of the fuse. The other end of the third resistor R3 is electrically connected to one end of the fourth resistor R4. The other end of the fourth resistor R4 is electrically connected to the first driving output end DSG. One end of the fourth resistor R4 is electrically connected to the gate of the first MOS Q1 and the controlled end of the discharge control switch module, respectively.

[0043] One end of the fifth resistor R5 is used to be electrically connected to the positive electrode of the lithium battery. The other end of the fifth resistor R5 is electrically connected to one end of the sixth resistor R6. The other end of the sixth resistor R6 is electrically connected to the second driving output end CHG. One end of the sixth resistor R6 is electrically connected to the gate of the second MOS Q2.

[0044] One end of the seventh resistor R7 is electrically connected to the battery end voltage measurement input end VC1 of the battery charging and discharging management chip U2. The other end of the seventh resistor R7 is used to be connected between two adjacent battery cells. One end of the eighth resistor R8 is electrically connected to the other end of the fuse. The other end of the eighth resistor R8 is electrically connected to the sensing input end PACK of the battery charging and discharging management chip U2. One end of the ninth resistor R9 is used to be connected to the positive electrode of the lithium battery. The other end of the ninth resistor R9 is electrically connected to the charging end voltage measurement input end VC2 of the battery charging and discharging management chip U2. The power input pin PBI of the battery charging and discharging management chip U2 is grounded through the eighth capacitor C8 in series. The battery end voltage measurement input end VC1 is electrically connected to one end of the sixth capacitor C6. The charging end voltage measurement input end VC2 is electrically connected to the other end of the sixth capacitor C6, so as to filter out the noise between the battery end voltage measurement input end VC1 and the charging end voltage measurement input end VC2. The battery end voltage measurement input end VC1 is also electrically connected to one end of the seventh capacitor C7. The other end of the seventh capacitor C7 is grounded, so as to filter out the noise of the battery end voltage measurement input end VC1 by using the seventh capacitor C7.

[0045] BQ28Z610 battery charge and discharge management chip provides a battery pack based on the integrated solution, the solution has flash programmable custom RISC, security and authentication function, suitable for series lithium ion and lithium polymer battery pack, improve the convenience of battery charge and discharge management.

[0046] In some embodiments, the leakage control switch module includes a triode Q3 and a tenth resistor R10, the emitter of the triode Q3 is electrically connected with the other end of the fuse, the collector of the triode Q3 is electrically connected with one end of the tenth resistor R10, the other end of the tenth resistor R10 is grounded, and the base of the triode Q3 is electrically connected with one end of the fourth resistor R4. The triode Q3 is specifically selected as a PNP triode. The PNP triode is composed of two P-type semiconductors and one N-type semiconductor, so it is called PNP triode. It can also be described as a triode with current flowing from the emitter E. When the first drive output end DSG is low, the external charging device is cut off, and a large instantaneous current appears, the base of the triode Q3 is pulled low to low, the triode Q3 is turned on, the large instantaneous current flows from the emitter of the triode Q3 to the collector, and is discharged through the tenth resistor 10 to reduce the large instantaneous current on the charging circuit.

[0047] In some embodiments, the charge count acquisition module includes an eleventh resistor R11, a twelfth resistor R12 and a thirteenth resistor R13, one end of the eleventh resistor R11 is electrically connected with one coulomb count access end SRN of the battery charge and discharge management chip U2, the other end of the eleventh resistor R11 is electrically connected with one end of the thirteenth resistor R13, one end of the thirteenth resistor R13 is electrically connected with the second charge connection end PN, the other end of the thirteenth resistor R13 is grounded, and the other end of the thirteenth resistor R13 is used for connecting the negative electrode of the lithium battery; one end of the twelfth resistor R12 is electrically connected with another coulomb count access end SRP of the battery charge and discharge management chip U2, and the other end of the twelfth resistor R12 is electrically connected with the other end of the thirteenth resistor R13.

[0048] In some embodiments, the charging count collection module further comprises a first capacitor C1, a second capacitor C2 and a third capacitor C3, one end of the first capacitor C1 is electrically connected with one coulomb count access end SRN of the battery charging and discharging management chip U2, the other end of the first capacitor C1 is grounded, one end of the second capacitor C2 is electrically connected with another coulomb count access end SRP of the battery charging and discharging management chip U2, the other end of the second capacitor C2 is grounded; one end of the third capacitor C3 is electrically connected with one coulomb count access end SRN of the battery charging and discharging management chip U2, the other end of the third capacitor C3 is electrically connected with another coulomb count access end SRP of the battery charging and discharging management chip U2. The capacitors are respectively connected between the two coulomb count access ends of the battery charging and discharging management chip U2 and the ground wire to filter out the noise of each coulomb count access end to the ground; at the same time, the capacitors are connected between the two coulomb count access ends to filter out the noise between the two coulomb count access ends of the battery charging and discharging management chip U2, so as to improve the accuracy and stability of the coulomb count.

[0049] In some embodiments, the temperature sensor is a thermistor PT1, one end of the thermistor PT1 is electrically connected with a temperature data input end TS1 of the battery charging and discharging management chip U2, the other end of the thermistor PT1 is grounded.

[0050] As shown in Figure 1 and 3 In some embodiments, the temperature sensor is a thermistor PT1, one end of the thermistor PT1 is electrically connected with a temperature data input end TS1 of the battery charging and discharging management chip U2, the other end of the thermistor PT1 is grounded.

[0051] One end of the thirteenth resistor R13 is electrically connected with a serial clock end SCL of the battery charging and discharging management chip U2, the other end of the thirteenth resistor R13 is electrically connected with one end of the fifteenth resistor R15 and a negative electrode of the second unidirectional voltage stabilizing diode D4 respectively, the other end of the fifteenth resistor R15 is used for accessing a serial clock end of an external signal processing device, the positive electrode of the second unidirectional voltage stabilizing diode D4 is electrically connected with the second charging connection end PN.

[0052] In some embodiments, the fuse is a fuse wire, the rated current of the fuse wire is 10A, and the rated voltage of the fuse wire is 24V. When the charging current is too large, the fuse wire is fused to cut off the charging circuit, thereby ensuring the safety of the charging circuit and the battery. One end of the fuse is electrically connected to one end of the fourth capacitor C4, and the other end of the fourth capacitor C4 is grounded. By arranging the fourth capacitor C4, the noise of the input voltage at one end of the fuse can be filtered out, thereby improving the stability of the charging voltage.

[0053] The battery charge and discharge management chip U2 is provided with a coulomb counter. The working principle of the coulomb counter is to connect a detection resistor, such as the thirteenth resistor R13 in the embodiment, in the charging or discharging path of the battery. The ADC measures the voltage on the detection resistor, and then transmits the current value when the battery is charging or discharging. The real-time counter RTC integrates the current into the coulomb information to provide a timing basis. The coulomb counter provides accurate short-term SOC reporting accuracy during charging or discharging. The remaining capacity RM and the full charging capacity FCC information can be reported through the charging coulomb counter CCR and the discharging coulomb counter DCR, and the SOC can be reported through the RM and FCC SOC-RM / FCC. In addition, it can also provide remaining time estimation, such as emptying time TTE and full charging time TTF.

[0054] The temperature protection principle of the lithium battery is as follows:

[0055] The battery charge and discharge management chip U2 can set the charging temperature to 0-45℃ and the discharging temperature to -20-60℃ through a programmable communication IC. When the communication IC reads the external NTC value through the TS1 pin, the value is converted by the ADC module inside the battery charge and discharge management chip U2. According to the state of the battery at this time, whether it is discharging or charging, it is judged whether the temperature value at this time exceeds the range. When the battery temperature exceeds the range during discharging, the battery charge and discharge management chip U2 sets the first drive output end DSG to low, so that the first MOS tube Q1 is disconnected, and the first charging connection end PA loses power, i.e. the one end of the third resistor R3 connected to the MOS tube loses power, so as to close the discharging channel.

[0056] When the battery temperature exceeds the range during charging, the one end of the fifth resistor R5 is connected to the positive electrode of the lithium battery and continuously supplies power. The battery charge and discharge management chip U2 sets the second drive output end CHG to low, and the one end voltage of the sixth resistor R6 is pulled low, so that the second MOS tube Q2 is cut off, thereby closing the charging channel.

[0057] The charge and discharge management principle is as follows:

[0058] (1) Normal state, i.e. normal charging state:

[0059] In the normal charging state, the first driving output end DSG and the second driving output end CHG of the battery charge and discharge management chip U2 are in high level state, the first MOS Q1 and the second MOS Q2 are turned on, and the battery is normally charged.

[0060] In the normal discharging state, the first driving output end DSG of the battery charge and discharge management chip U2 is in high level state, the second driving output end CHG is in high level state, the first MOS Q1 and the first MOS Q1 are continuously turned on, and the positive electrode of the lithium battery is turned on with the first charging connection end PA.

[0061] (2) Overcharge protection

[0062] During charging, the battery charge and discharge management chip U2 always monitors the voltage difference between the battery voltage measurement input end VC1 and the charging voltage measurement input end VC2 and the ground end VSS, and when any voltage difference is greater than the corresponding overcharge cutoff voltage, the battery charge and discharge management chip U2 sets the first driving output end DSG to low level to close the first MOS, at this time the charging loop is cut off, and the battery can only be discharged. For example: when the battery is discharged, the load can be connected to the drain of the first MOS Q1 or the second MOS Q2 to supply power for the battery discharge.

[0063] (3) Over-discharge protection

[0064] During discharging, the battery charge and discharge management chip U2 always monitors the voltage difference between the battery voltage measurement input end VC1 and the charging voltage measurement input end VC2 and the ground end VSS, and when any voltage difference is less than the corresponding over-discharge cutoff voltage, the battery charge and discharge management chip U2 will change the second driving output end CHG to low level to close the second MOS, at this time the discharging loop is cut off.

[0065] The above only describes the preferred embodiments of the present application, and does not limit the present application, any modification, equivalent replacement, improvement, etc. within the concept and principle of the present application, should be included in the protection scope of the present application.

Claims

1. A multi-charge protection circuit for a lithium battery, characterized in that: The fuse, the charging control switch module, the discharge control switch module, the battery charging and discharging management module, the temperature sensor, the charging count acquisition module, the first charging connection end (PA) and the second charging connection end (PN); the first charging connection end (PA) is used for connecting the positive electrode of the output end of the charging device, and the second charging connection end (PN) is used for connecting the negative electrode of the output end of the charging device; One end of the fuse is electrically connected with the first charging connection end (PA), and the other end of the fuse is electrically connected with one end of the charging control switch module and one end of the discharge control switch module respectively, the other end of the discharge control switch module is grounded, and the other end of the charging control switch module is used for connecting the positive electrode of the lithium battery; one end of the charging count acquisition module is electrically connected with the second charging connection end (PN), and the other end of the charging count acquisition module is grounded, and the other end of the charging count acquisition module is used for connecting the negative electrode of the lithium battery; wherein the lithium battery comprises a plurality of electric cores connected in series. The output end of the temperature sensor is electrically connected with the temperature data input end of the battery charging and discharging management module, the charging end voltage measurement input end of the battery charging and discharging management module is used for connecting the positive electrode of the lithium battery, the battery end voltage measurement input end of the battery charging and discharging management module is used for connecting between two adjacent electric cores, and the drive output end of the battery charging and discharging management module is electrically connected with the controlled end of the charging control switch module and the controlled end of the discharge control switch module respectively; the two coulomb count access ends of the battery charging and discharging management module are electrically connected with the two ends of the charging count acquisition module respectively.

2. The multiple charge protection circuit for a lithium battery according to claim 1, wherein: The charging control switch module comprises a first MOS tube (Q1) and a second MOS tube (Q2), the drain of the first MOS tube (Q1) is electrically connected with the drain of the second MOS tube (Q2), the source of the first MOS tube (Q1) is electrically connected with the other end of the fuse, the source of the second MOS tube (Q2) is used for connecting the positive electrode of the lithium battery, and the drive output end of the battery charging and discharging management module is electrically connected with the gate of the first MOS tube (Q1) and the gate of the second MOS tube (Q2) respectively.

3. The multiple charge protection circuit for a lithium battery of claim 2, wherein: The charging control switch module further comprises a first resistor (R1), a second resistor (R2), a first bidirectional voltage stabilizing diode (D1) and a second bidirectional voltage stabilizing diode (D2); one end of the first resistor (R1) is electrically connected with the gate of the first MOS tube (Q1), one end of the second resistor (R2) is electrically connected with the gate of the second MOS tube (Q2), the drive output end of the battery charging and discharging management module is electrically connected with the other end of the first resistor (R1) and the other end of the second resistor (R2) respectively; one end of the first bidirectional voltage stabilizing diode (D1) is electrically connected with the source of the first MOS tube (Q1), the other end of the first bidirectional voltage stabilizing diode (D1) is electrically connected with the other end of the first resistor (R1); one end of the second bidirectional voltage stabilizing diode (D2) is electrically connected with the source of the second MOS tube (Q2), the other end of the second bidirectional voltage stabilizing diode (D2) is electrically connected with the other end of the second resistor (R2).

4. The multiple charge protection circuit for a lithium battery of claim 2, wherein: The battery charging and discharging management module comprises a battery charging and discharging management chip (U2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6), a seventh resistor (R7), an eighth resistor (R8) and a ninth resistor (R9), the model of the battery charging and discharging management chip (U2) is BQ28Z610, the drive output end of the battery charging and discharging management chip (U2) comprises a first drive output end and a second drive output end; one end of the third resistor (R3) is electrically connected with the other end of the fuse, the other end of the third resistor (R3) is electrically connected with one end of the fourth resistor (R4), the other end of the fourth resistor (R4) is electrically connected with the first drive output end, one end of the fourth resistor (R4) is electrically connected with the gate of the first MOS tube (Q1) and the controlled end of the discharge control switch module respectively; one end of the fifth resistor (R5) is used for being electrically connected with the positive electrode of the lithium battery, the other end of the fifth resistor (R5) is electrically connected with one end of the sixth resistor (R6), the other end of the sixth resistor (R6) is electrically connected with the second drive output end, one end of the sixth resistor (R6) is electrically connected with the gate of the second MOS tube (Q2); one end of the seventh resistor (R7) is electrically connected with the battery end voltage measurement input end of the battery charging and discharging management chip (U2), the other end of the seventh resistor (R7) is used for being connected between two adjacent battery cells; one end of the eighth resistor (R8) is electrically connected with the other end of the fuse, the other end of the eighth resistor (R8) is electrically connected with the sensing input end of the battery charging and discharging management chip (U2); one end of the ninth resistor (R9) is used for connecting the positive electrode of the lithium battery, the other end of the ninth resistor (R9) is electrically connected with the charging end voltage measurement input end of the battery charging and discharging management chip (U2).

5. The multiple charge protection circuit for a lithium battery of claim 4, wherein: The leakage control switch module comprises a triode (Q3) and a tenth resistor (R10), one end of the tenth resistor (R10) is electrically connected to the other end of the fuse, the other end of the tenth resistor (R10) is grounded, and the base of the triode (Q3) is electrically connected to one end of the fourth resistor (R4).

6. The multiple charge protection circuit for a lithium battery of claim 4, wherein: The charge count acquisition module comprises an eleventh resistor (R11), a twelfth resistor (R12) and a thirteenth resistor (R13), one end of the eleventh resistor (R11) is electrically connected to one of the coulomb count access ends of the battery charge and discharge management chip (U2), the other end of the eleventh resistor (R11) is electrically connected to one end of the thirteenth resistor (R13), one end of the thirteenth resistor (R13) is electrically connected to the second charging connection end (PN), the other end of the thirteenth resistor (R13) is grounded, and the other end of the thirteenth resistor (R13) is used for connecting the negative electrode of the lithium battery; one end of the twelfth resistor (R12) is electrically connected to the other coulomb count access end of the battery charge and discharge management chip (U2), and the other end of the twelfth resistor (R12) is electrically connected to the other end of the thirteenth resistor (R13).

7. The multiple charge protection circuit for a lithium battery of claim 6, wherein: The charge count acquisition module further comprises a first capacitor (C1), a second capacitor (C2) and a third capacitor (C3), one end of the first capacitor (C1) is electrically connected to one of the coulomb count access ends of the battery charge and discharge management chip (U2), the other end of the first capacitor (C1) is grounded, one end of the second capacitor (C2) is electrically connected to the other coulomb count access end of the battery charge and discharge management chip (U2), and the other end of the second capacitor (C2) is grounded; one end of the third capacitor (C3) is electrically connected to one of the coulomb count access ends of the battery charge and discharge management chip (U2), and the other end of the third capacitor (C3) is electrically connected to the other coulomb count access end of the battery charge and discharge management chip (U2).

8. The multiple charge protection circuit for a lithium battery of claim 4, wherein: The temperature sensor is a thermistor (PT1), one end of the thermistor (PT1) is electrically connected to the temperature data input end of the battery charge and discharge management chip (U2), and the other end of the thermistor (PT1) is grounded.

9. The multiple charge protection circuit for a lithium battery of claim 4, wherein: The external output module comprises a thirteenth resistor (R13), a fourteenth resistor (R14), a fifteenth resistor (R15), a sixteenth resistor (R16), a first unidirectional voltage stabilizing diode (D3) and a second unidirectional voltage stabilizing diode (D4). One end of the thirteenth resistor (R13) is electrically connected with the serial clock end of the battery charging and discharging management chip (U2), the other end of the thirteenth resistor (R13) is respectively electrically connected with one end of the fifteenth resistor (R15) and the negative electrode of the second unidirectional voltage stabilizing diode (D4), the other end of the fifteenth resistor (R15) is used for accessing the serial clock end of the external signal processing device, and the positive electrode of the second unidirectional voltage stabilizing diode (D4) is electrically connected with the second charging connection end (PN). One end of the fourteenth resistor (R14) is electrically connected with the serial data end of the battery charging and discharging management chip (U2), the other end of the fourteenth resistor (R14) is respectively electrically connected with one end of the sixteenth resistor (R16) and the negative electrode of the first unidirectional voltage stabilizing diode (D3), the other end of the sixteenth resistor (R16) is used for accessing the serial data end of the external signal processing device, and the positive electrode of the first unidirectional voltage stabilizing diode (D3) is electrically connected with the second charging connection end (PN).

10. The multiple charge protection circuit for a lithium battery of claim 1, wherein: The fuse is a fuse, the rated current of the fuse is 10A, and the rated voltage of the fuse is 24V.

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