CN212518490U - Lithium battery protection circuit - Google Patents
Lithium battery protection circuit Download PDFInfo
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- CN212518490U CN212518490U CN202021640173.7U CN202021640173U CN212518490U CN 212518490 U CN212518490 U CN 212518490U CN 202021640173 U CN202021640173 U CN 202021640173U CN 212518490 U CN212518490 U CN 212518490U
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Abstract
The embodiment of the utility model provides a lithium battery protection circuit, lithium battery protection circuit includes: the device comprises a lithium battery pack, a battery protection module and a charge and discharge control module; the battery protection module comprises a first resistor, a first capacitor, a second resistor and a battery protection chip; the lithium battery protection circuit also comprises a load input end and a load output end; the input end of the first resistor is connected with the anode of the lithium battery pack and the load input end; the output end of the first resistor is connected with the battery protection chip and the input end of the first capacitor; the output end of the first capacitor is connected with the battery protection chip, the negative electrode of the lithium battery pack and the charge and discharge control module; the input end of the second resistor is connected with the battery protection chip; the output end of the second resistor is connected with the charge-discharge control module and the load output end; the anode of the lithium battery pack is connected with the load input end; the charge and discharge control module is connected with the load output end; the safety and the stability of the work of the lithium battery can be protected in the process of charging or discharging the lithium battery.
Description
Technical Field
The utility model relates to the technical field of circuits, concretely relates to lithium battery protection circuit.
Background
Currently, problems occurring in the lithium battery pack during use generally include that the battery voltage is too high due to overcharge, the battery voltage is too low due to overdischarge, a short circuit occurs inside the battery, or the current is too large due to other reasons, and therefore, in order to protect the lithium battery to safely operate during use, a lithium battery protection circuit capable of protecting the lithium battery to safely operate needs to be designed.
SUMMERY OF THE UTILITY MODEL
An embodiment of the utility model provides a lithium battery protection circuit can charge or the in-process that discharges at the lithium cell, protects the security and the stability of lithium cell work.
The utility model provides a first aspect of the embodiment provides a lithium battery protection circuit, include: the device comprises a lithium battery pack, a battery protection module and a charge and discharge control module; the battery protection module comprises a first resistor, a first capacitor, a second resistor and a battery protection chip; the charge and discharge control module comprises a first field effect tube and a second field effect tube; the lithium battery protection circuit also comprises a load input end and a load output end which are used for connecting a load; wherein the content of the first and second substances,
the input end of the first resistor is connected with the anode of the lithium battery pack, and the input end of the first resistor is also connected with the load input end;
the output end of the first resistor is connected with the battery protection chip, and the output end of the first resistor is also connected with the input end of the first capacitor;
the output end of the first capacitor is connected with the battery protection chip; the output end of the first capacitor is also connected with the negative electrode of the lithium battery pack; the output end of the first capacitor is also connected with the charge and discharge control module;
the input end of the second resistor is connected with the battery protection chip; the output end of the second resistor is connected with the charge and discharge control module; the output end of the second resistor is also connected with the load output end;
the anode of the lithium battery pack is connected with the load input end; the charge and discharge control module is connected with the load output end; and the charge and discharge control module is connected with the negative electrode of the lithium battery pack.
Optionally, the battery protection module further includes a third resistor, and an input end of the third resistor is connected to an external temperature detection device; the output end of the third resistor is connected with the charge and discharge control module; the third resistor is also connected with the load output end.
Optionally, the battery protection chip includes: the system comprises an overcharge/discharge detection circuit, an oscillation control module, a frequency division control module, an output control module, a short circuit detection module, an overcurrent detection module and a charge detection module; the battery protection chip further includes: an over-discharge protection control pin, a detection pin, an over-charge protection control pin, a blank pin, a power supply pin and a grounding pin; wherein the content of the first and second substances,
the overcharge/discharge detection circuit is respectively connected with the power supply pin and the grounding pin; the overcharge/discharge detection circuit is also connected with the oscillation control module;
the oscillation control module is also connected with the short circuit detection module, the overcurrent detection module, the charging detection module and the frequency division control module;
the frequency division control module is also connected with the output control module;
the output control module is respectively connected with the over-discharge protection control pin and the over-charge protection control pin;
the short circuit detection module, the overcurrent detection module and the charging detection module are also connected with the detection pins;
the power supply pin is connected with the output end of the first resistor and the input end of the first capacitor;
the grounding pin is connected with the output end of the first capacitor and the negative electrode of the lithium battery pack;
the overdischarge protection control pin is connected with the first field effect transistor; the overcharge protection control pin is connected with the second field effect transistor;
the detection pin is connected with the input end of the second resistor.
Optionally, the overcharge/discharge detection circuit includes an overcharge detection resistor, a first variable resistor, a first amplifier, an overdischarge detection resistor, a second variable resistor, a second amplifier, and a first power supply; wherein the content of the first and second substances,
one end of the first variable resistor is connected with the power supply pin and one section of the second variable resistor; the other end of the first variable resistor is connected with one end of the overcharge detection resistor and the positive input end of the first amplifier;
the other end of the overcharge detection resistor is connected with the grounding pin and the negative electrode of the first power supply;
the other end of the second variable resistor is connected with one end of the over-discharge detection resistor and the positive electrode input end of the second amplifier;
the other end of the over-discharge detection resistor is connected with the grounding pin and the negative electrode of the first power supply;
the anode of the first power supply is respectively connected with the cathode input end of the first amplifier and the cathode input end of the second amplifier;
the output end of the first amplifier and the output end of the second amplifier are respectively connected with the oscillation control module.
Optionally, the short-circuit detection module includes a third amplifier and a second power supply, and an anode input end of the third amplifier is connected to an anode of the second power supply; the negative electrode input end of the third amplifier is connected with the detection pin;
the overcurrent detection module comprises a fourth amplifier and a third power supply, and the positive electrode input end of the fourth amplifier is connected with the positive electrode of the third power supply; the negative electrode input end of the fourth amplifier is connected with the detection pin;
the charging detection module comprises a fifth amplifier and a fourth power supply, and the positive electrode input end of the fifth amplifier is connected with the positive electrode of the fourth power supply; the negative electrode input end of the fifth amplifier is connected with the detection pin;
the negative electrodes of the second power supply, the third power supply and the fourth power supply are connected with the grounding pin in an equipotential manner; and the output ends of the third amplifier, the fourth amplifier and the fifth amplifier are respectively connected with the oscillation control module.
Optionally, the battery protection chip further includes a charging control circuit, and the charging control circuit is connected to the output control module and the detection pin.
Optionally, a first source port of the first field effect transistor is connected to a negative electrode of the lithium battery pack, an output terminal of the first capacitor, and a ground pin of the battery protection chip, respectively;
a second port of the source electrode of the first field effect transistor is respectively connected with an output port of the second resistor and an output port of the load;
a first port of a drain electrode of the first field effect transistor is connected with a second port of the drain electrode of the first field effect transistor;
a first gate port of the first field effect transistor is connected with the overdischarge protection control pin; and a second gate port of the first field effect transistor is connected with the overcharge protection control pin.
Optionally, a first port of a source of the second field effect transistor is connected to an output port of the second resistor and an output port of the load, respectively;
a second port of a source electrode of the second field effect transistor is respectively connected with a negative electrode of the lithium battery pack, an output end of the first capacitor and a grounding pin of the battery protection chip;
the first port of the drain electrode of the second field effect transistor is connected with the first port of the drain electrode and the second port of the drain electrode of the first field effect transistor;
a second gate port of the first field effect transistor is connected with the overdischarge protection control pin; and a first gate port of the first field effect transistor is connected with the overcharge protection control pin.
Implement the embodiment of the utility model provides a, following beneficial effect has at least:
it can be seen, through the utility model provides an in the embodiment of the lithium battery protection circuit, include: the device comprises a lithium battery pack, a battery protection module and a charge and discharge control module; the battery protection module comprises a first resistor, a first capacitor, a second resistor and a battery protection chip; the charging and discharging control module comprises a first field effect tube and a second field effect tube; the lithium battery protection circuit also comprises a load input end and a load output end which are used for connecting a load; the input end of the first resistor is connected with the anode of the lithium battery pack, and the input end of the first resistor is also connected with the load input end; the output end of the first resistor is connected with the battery protection chip, and the output end of the first resistor is also connected with the input end of the first capacitor; the output end of the first capacitor is connected with the battery protection chip; the output end of the first capacitor is also connected with the negative electrode of the lithium battery pack; the output end of the first capacitor is also connected with a charge-discharge control module; the input end of the second resistor is connected with the battery protection chip; the output end of the second resistor is connected with the charge and discharge control module; the output end of the second resistor is also connected with the load output end; the anode of the lithium battery pack is connected with the load input end; the charge and discharge control module is connected with the load output end; the charge and discharge control module is connected with the negative electrode of the lithium battery pack, so that the working safety and stability of the lithium battery can be protected in the process of charging or discharging the lithium battery.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a lithium battery protection circuit according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a battery protection chip according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another lithium battery protection circuit provided in an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The terms "first," "second," and the like in the description and in the claims, and in the drawings described above, are used for distinguishing between different objects and not necessarily for describing a particular sequential or chronological order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.
Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by a person skilled in the art that the described embodiments of the invention can be combined with other embodiments.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a lithium battery protection circuit according to an embodiment of the present invention, as shown in fig. 1, the schematic structural diagram of the lithium battery protection circuit of the present invention may include: the device comprises a lithium battery pack, a battery protection module and a charge and discharge control module; the battery protection module comprises a first resistor R1, a first capacitor C1, a second resistor R2 and a battery protection chip U1; the charging and discharging control module comprises a first field effect transistor Q1 and a second field effect transistor Q2; the lithium battery protection circuit further comprises a load input end P + and a load output end P-which are used for connecting a load; wherein the content of the first and second substances,
the input end of the first resistor R1 is connected with the positive pole B + of the lithium battery pack, and the input end of the first resistor R1 is also connected with the load input end;
the output end of the first resistor R1 is connected with the battery protection chip, and the output end of the first resistor R1 is also connected with the input end of the first capacitor C1;
the output end of the first capacitor C1 is connected with the battery protection chip U1; the output end of the first capacitor C1 is also connected with the negative electrode B-of the lithium battery pack; the output end of the first capacitor C1 is also connected with the charge and discharge control module;
the input end of the second resistor R2 is connected with the battery protection chip U1; the output end of the second resistor R2 is connected with the charge and discharge control module; the output end of the second resistor R2 is also connected with the load output end P-;
the anode B + of the lithium battery pack is connected with the load input end P +; the charge and discharge control module is connected with the load output end P < - >; the charge and discharge control module is connected with a negative electrode B-of the lithium battery pack.
The first resistor R1 is used for limiting current, stabilizing the battery voltage VCC, and enhancing the electrostatic discharge protection; the second resistor R2 is used for limiting current; c1 is used to filter and stabilize the battery voltage VCC.
The first field effect transistor Q1 is used for charge control; the second field effect transistor Q2 is used for discharge control. In specific implementation, the charging can be carried out by turning on the first field effect transistor Q1; the discharge can be performed by turning on the second field effect transistor Q2.
Optionally, the battery protection chip U1 includes: the system comprises an overcharge/discharge detection circuit, an oscillation control module, a frequency division control module, an output control module, a short circuit detection module, an overcurrent detection module and a charge detection module; the battery protection chip further includes: an over-discharge protection control pin OD, a detection pin CS, an over-charge protection control pin OC, a blank pin NC, a power supply pin VDD and a grounding pin GND; wherein the content of the first and second substances,
the overcharge/discharge detection circuit is respectively connected with the power supply pin VDD and the grounding pin GND; the overcharge/discharge detection circuit is also connected with the oscillation control module;
the oscillation control module is also connected with the short circuit detection module, the overcurrent detection module, the charging detection module and the frequency division control module;
the frequency division control module is also connected with the output control module;
the output control module is respectively connected with the over-discharge protection control pin OD and the over-charge protection control pin OC;
the short circuit detection module, the overcurrent detection module and the charging detection module are also connected with the detection pin CS;
the power supply pin VDD is connected with the output end of the first resistor R1 and the input end of the first capacitor C1;
the grounding pin GND is connected with the output end of the first capacitor C1 and the negative electrode B-of the lithium battery pack;
the over-discharge protection control pin OD is connected with the first field effect transistor Q1; the overcharge protection control pin OC is connected with the second field effect transistor Q2;
the detection pin CS is connected to an input terminal of the second resistor R2.
Referring to fig. 2, fig. 2 is a schematic structural diagram of a battery protection chip according to an embodiment of the present invention; when the battery voltage VCC exceeds a preset over-discharge detection voltage VODP and is less than a preset over-charge detection voltage VOCP, the detection voltage VCS is greater than a preset charger detection voltage VCH and is less than a preset over-discharge over-current detection voltage VOI1, the over-charge protection control pin OC and the over-discharge protection control pin OD of the battery protection chip both output high levels, so that the first field effect transistor Q1 and the second field effect transistor Q2 are simultaneously conducted, and the lithium battery enters a normal working state.
In the charging overcharge, when the battery voltage VCC is higher than the overcharge detection voltage VOCP and the charging time exceeds the preset overcharge delay time TOC, the charging can be stopped by turning off the first fet Q1 for charge control, and the overcharge protection state is entered.
The overcharge delay time may be 70ms, for example.
The overcharge protection state can be released and the first field effect transistor Q1 can be turned back on when either of the following conditions is satisfied:
the battery voltage VCC drops to be lower than the preset overcharge release voltage VOCR through self-discharge of the battery; alternatively, the first and second electrodes may be,
the battery voltage VCC drops below the preset overcharge detection voltage VOCP and a load is connected.
In a specific implementation, when the battery voltage VCC is higher than the preset overcharge detection voltage VOCP, the overcharge protection state is not released even in the case where one load is connected.
In the discharge overcharge, when the battery voltage VCC falls below the overdischarge detection voltage VODP and the state continues for a time exceeding the preset discharge detection delay time TOD, the discharge-controlled second fet Q2 may be turned off to stop the discharge, and the overdischarge protection state is entered.
The over-discharge protection state is released and the second fet Q2 is turned back on when either:
the lithium battery pack is connected with a charger, if the detection voltage VCS between the CS pin and the GND is lower than the preset charger detection voltage VCH, when the battery voltage VCC is higher than the preset overdischarge detection voltage VODP, the overdischarge protection state is released, and the conduction of the second field effect transistor Q2 is restored; alternatively, the first and second electrodes may be,
the lithium battery pack is connected with the charger, if the detection voltage VCS between the CS pin and the GND is higher than the detection voltage VCH of the charger, when the battery voltage VCC is higher than the overdischarge release voltage VODR, the overdischarge protection state is released, and the conduction of the second field effect transistor Q2 is restored; alternatively, the first and second electrodes may be,
when the charger is not connected, if the battery voltage VCC is recovered to be higher than the overdischarge release voltage VODR, the overdischarge protection state is released, and the second fet Q2 is turned on again.
The discharge current can be continuously monitored by the detection voltage VCS between the CS pin and GND. If the detection voltage VCS is higher than the preset overcurrent protection voltage and exceeds the preset overcurrent delay period, the overcurrent protection circuit is started, and the second field effect transistor Q2 for discharge control can be turned off. When the load is unloaded and the positive electrode B + and the negative electrode B-of the lithium battery pack are in high resistance, the overcurrent protection is removed, and the second field effect transistor Q2 can be restored to be conducted.
The detection of the load after the overcharge is realized by detecting a detection voltage VCS between the CS pin and the GND. When a load is connected to the lithium battery pack after overcharging, the discharge current flows through the parasitic diode of the first fet Q1 to form a diode voltage drop between the CS pin and GND. The load is detectable if the detection voltage VCS is higher than a preset load detection threshold voltage VLD.
When over-discharging, the discharge control second field effect transistor Q2 is turned off, so that discharge over-charging is prohibited. But charging overcharge by the parasitic diode of the second fet Q2 is permitted. When the charger is connected to the lithium battery pack, the charging process can be detected if the 8 detection voltage VCS between the CS pin and GND is lower than the preset charger detection voltage VCH.
Alternatively, the overcharge/discharge detection circuit includes an overcharge detection resistor Rc1, a first variable resistor Rs1, a first amplifier K1, an overdischarge detection resistor Rc2, a second variable resistor Rs2, a second amplifier K2, and a first power supply E1; wherein the content of the first and second substances,
one end of the first variable resistor Rs1 is connected to the power supply pin VDD and one section of the second variable resistor Rs 2; the other end of the first variable resistor Rs1 is connected to one end of the overcharge detection resistor Rc1 and the positive input terminal of the first amplifier K1;
the other end of the overcharge detection resistor Rc1 is connected to the ground pin VDD and the negative electrode of the first power supply E1;
the other end of the second variable resistor Rs2 is connected to one end of the overdischarge detection resistor Rc2 and the positive input end of the second amplifier;
the other end of the over-discharge detection resistor Rc2 is connected to the ground pin GND and the negative electrode of the first power supply E1;
the positive pole of the first power supply E1 is respectively connected with the negative pole input end of the first amplifier K1 and the negative pole input end of the second amplifier K2;
the output end of the first amplifier K1 and the output end of the second amplifier K2 are respectively connected with the oscillation control module.
Optionally, the short circuit detection module comprises a third amplifier K3 and a second power supply E2, and a positive input terminal of the third amplifier K3 is connected with a positive electrode of the second power supply E2; the negative electrode input end of the third amplifier K3 is connected with the detection pin CS;
the over-current detection module comprises a fourth amplifier K4 and a third power supply E3, wherein the positive input end of the fourth amplifier K4 is connected with the positive electrode of the third power supply E3; the negative electrode input end of the fourth amplifier K4 is connected with the detection pin CS;
the charging detection module comprises a fifth amplifier K5 and a fourth power supply E4, wherein the positive input end of the fifth amplifier K5 is connected with the positive electrode of the fourth power supply E4; the negative electrode input end of the fifth amplifier K5 is connected with the detection pin CS;
the cathodes of the second power supply E2, the third power supply E3 and the fourth power supply E4 are connected with the ground pin GND in an equal potential; the output ends of the third amplifier K3, the fourth amplifier K4 and the fifth amplifier K5 are respectively connected with the oscillation control module.
Optionally, the battery protection chip further includes a charging control circuit, and the charging control circuit is connected to the output control module and the detection pin CS.
The charging control circuit is used for charging the 0V battery. In particular, it can be used to recharge batteries that have self-discharged to 0V. When the charger voltage connected between the battery anode B + and the battery cathode B-is higher than the charger starting voltage VOV for charging the 0V battery, the grid electrode of the first field effect transistor Q1 for charge control is fixed to the voltage of the VDD pin, and the voltage difference between the grid electrode and the source electrode of the first field effect transistor Q1 is higher than the conducting voltage due to the charger voltage, so that the first field effect transistor Q1 for charge control is turned on to start charging. The second fet Q2 is still off, and the charging current flows through its internal parasitic diode. And when the battery voltage VCC is higher than the overdischarge detection voltage VODP, entering a normal working state.
Optionally, the source first port S1 of the first field effect transistor Q1 is respectively connected to the negative electrode of the lithium battery pack, the output end of the first capacitor C1, and the ground pin GND of the battery protection chip;
a second source port S2 of the first field effect transistor Q1 is respectively connected with an output port P-of the second resistor R2 and an output port P-of a load;
the drain electrode first port D1 of the first field effect transistor Q1 is connected with the drain electrode second port of the first field effect transistor Q1;
a gate first port G1 of the first field effect transistor Q1 is connected with the over-discharge protection control pin OD; the gate second port G2 of the first field effect transistor Q1 is connected to the overcharge protection control pin OC.
Optionally, the source first port S2 of the second field effect transistor Q2 is respectively connected with the output port of the second resistor R2 and the output port P-of the load;
a second port of a source electrode of the second field effect transistor Q2 is respectively connected with a negative electrode of the lithium battery pack, an output end of the first capacitor and a grounding pin of the battery protection chip;
the drain first port D1 of the second field effect transistor Q2 is connected with the drain first port D1 and the drain second port D2 of the first field effect transistor Q1;
a gate second port G2 of the second field effect transistor Q2 is connected to the over-discharge protection control pin OD; the gate first port G1 of the second field effect transistor Q2 is connected to the overcharge protection control pin OC.
It can be seen that, in the embodiment of the present invention, the lithium battery protection circuit includes a lithium battery pack, a battery protection module and a charge and discharge control module; the battery protection module comprises a first resistor, a first capacitor, a second resistor and a battery protection chip; the lithium battery protection circuit also comprises a load input end and a load output end which are used for connecting a load; the input end of the first resistor is connected with the anode of the lithium battery pack, and the input end of the first resistor is also connected with the load input end; the output end of the first resistor is connected with the battery protection chip, and the output end of the first resistor is also connected with the input end of the first capacitor; the output end of the first capacitor is connected with the battery protection chip; the output end of the first capacitor is also connected with the negative electrode of the lithium battery pack; the output end of the first capacitor is also connected with a charge-discharge control module; the input end of the second resistor is connected with the battery protection chip; the output end of the second resistor is connected with the charge and discharge control module; the output end of the second resistor is also connected with the load output end; the anode of the lithium battery pack is connected with the load input end; the charge and discharge control module is connected with the load output end; the charge and discharge control module is connected with the negative electrode of the lithium battery pack, so that the working safety and stability of the lithium battery can be protected in the process of charging or discharging the lithium battery.
Further, please refer to fig. 3, fig. 3 is a schematic structural diagram of another lithium battery protection circuit according to an embodiment of the present invention. Wherein, the utility model provides a lithium battery protection circuit can include: the device comprises a lithium battery pack, a battery protection module and a charge and discharge control module; the battery protection module comprises a first resistor R1, a first capacitor C1, a second resistor R2 and a battery protection chip U1; the charging and discharging control module comprises a first field effect transistor Q1 and a second field effect transistor Q2; the lithium battery protection circuit further comprises a load input end P + and a load output end P-which are used for connecting a load; the battery protection module further comprises a third resistor R3, and the input end of the third resistor R3 is connected with an external temperature detection device; the output end of the third resistor is connected with the charge and discharge control module; the third resistor R3 is also connected with the load output end P-; wherein the content of the first and second substances,
the input end of the first resistor R1 is connected with the positive pole B + of the lithium battery pack, and the input end of the first resistor R1 is also connected with the load input end;
the output end of the first resistor R1 is connected with the battery protection chip, and the output end of the first resistor R1 is also connected with the input end of the first capacitor C1;
the output end of the first capacitor C1 is connected with the battery protection chip U1; the output end of the first capacitor C1 is also connected with the negative electrode B-of the lithium battery pack; the output end of the first capacitor C1 is also connected with the charge and discharge control module;
the input end of the second resistor R2 is connected with the battery protection chip U1; the output end of the second resistor R2 is connected with the charge and discharge control module; the output end of the second resistor R2 is also connected with the load output end P-;
the anode B + of the lithium battery pack is connected with the load input end P +; the charge and discharge control module is connected with the load output end P < - >; the charge and discharge control module is connected with a negative electrode B-of the lithium battery pack.
The third resistor R3 is used to limit current and stabilize the detection voltage VCS.
The input end of the third resistor R3 is connected with the input end T of the external temperature detection device, and the output end of the third resistor R3 is connected with the second source port S2 of the first field effect transistor Q1, the first source port S1 of the second field effect transistor Q2, the output end of the second resistor and the load output end P-.
It can be seen that, in the embodiment of the present invention, the lithium battery protection circuit includes a lithium battery pack, a battery protection module and a charge and discharge control module; the battery protection module comprises a first resistor, a first capacitor, a second resistor and a battery protection chip; the lithium battery protection circuit also comprises a load input end and a load output end which are used for connecting a load; the input end of the first resistor is connected with the anode of the lithium battery pack, and the input end of the first resistor is also connected with the load input end; the output end of the first resistor is connected with the battery protection chip, and the output end of the first resistor is also connected with the input end of the first capacitor; the output end of the first capacitor is connected with the battery protection chip; the output end of the first capacitor is also connected with the negative electrode of the lithium battery pack; the output end of the first capacitor is also connected with a charge-discharge control module; the input end of the second resistor is connected with the battery protection chip; the output end of the second resistor is connected with the charge and discharge control module; the output end of the second resistor is also connected with the load output end; the anode of the lithium battery pack is connected with the load input end; the charge and discharge control module is connected with the load output end; the charge and discharge control module is connected with the negative electrode of the lithium battery pack, so that the working safety and stability of the lithium battery can be protected in the process of charging or discharging the lithium battery.
Optionally, the battery protection chip U1 includes: the system comprises an overcharge/discharge detection circuit, an oscillation control module, a frequency division control module, an output control module, a short circuit detection module, an overcurrent detection module and a charge detection module; the battery protection chip further includes: an over-discharge protection control pin OD, a detection pin CS, an over-charge protection control pin OC, a blank pin NC, a power supply pin VDD and a grounding pin GND; wherein the content of the first and second substances,
the overcharge/discharge detection circuit is respectively connected with the power supply pin VDD and the grounding pin GND; the overcharge/discharge detection circuit is also connected with the oscillation control module;
the oscillation control module is also connected with the short circuit detection module, the overcurrent detection module, the charging detection module and the frequency division control module;
the frequency division control module is also connected with the output control module;
the output control module is respectively connected with the over-discharge protection control pin OD and the over-charge protection control pin OC;
the short circuit detection module, the overcurrent detection module and the charging detection module are also connected with the detection pin CS;
the power supply pin VDD is connected with the output end of the first resistor R1 and the input end of the first capacitor C1;
the grounding pin GND is connected with the output end of the first capacitor C1 and the negative electrode B-of the lithium battery pack;
the over-discharge protection control pin OD is connected with the first field effect transistor Q1; the overcharge protection control pin OC is connected with the second field effect transistor Q2;
the detection pin CS is connected to an input terminal of the second resistor R2.
Optionally, the overcharge/discharge detection circuit includes an overcharge detection resistor Rc1, a first variable resistor Rs1, a first amplifier K1, an overdischarge detection resistor Rc2, a second variable resistor Rs2, a second amplifier K2, and a first power supply E1; wherein the content of the first and second substances,
one end of the first variable resistor Rs1 is connected to the power supply pin VDD and one section of the second variable resistor Rs 2; the other end of the first variable resistor Rs1 is connected to one end of the overcharge detection resistor Rc1 and the positive input terminal of the first amplifier K1;
the other end of the overcharge detection resistor Rc1 is connected to the ground pin VDD and the negative electrode of the first power supply E1;
the other end of the second variable resistor Rs2 is connected to one end of the overdischarge detection resistor Rc2 and the positive input end of the second amplifier;
the other end of the over-discharge detection resistor Rc2 is connected to the ground pin GND and the negative electrode of the first power supply E1;
the positive pole of the first power supply E1 is respectively connected with the negative pole input end of the first amplifier K1 and the negative pole input end of the second amplifier K2;
the output end of the first amplifier K1 and the output end of the second amplifier K2 are respectively connected with the oscillation control module.
Optionally, the short circuit detection module comprises a third amplifier K3 and a second power supply E2, and a positive input terminal of the third amplifier K3 is connected with a positive electrode of the second power supply E2; the negative electrode input end of the third amplifier K3 is connected with the detection pin CS;
the over-current detection module comprises a fourth amplifier K4 and a third power supply E3, wherein the positive input end of the fourth amplifier K4 is connected with the positive electrode of the third power supply E3; the negative electrode input end of the fourth amplifier K4 is connected with the detection pin CS;
the charging detection module comprises a fifth amplifier K5 and a fourth power supply E4, wherein the positive input end of the fifth amplifier K5 is connected with the positive electrode of the fourth power supply E4; the negative electrode input end of the fifth amplifier K5 is connected with the detection pin CS;
the cathodes of the second power supply E2, the third power supply E3 and the fourth power supply E4 are connected with the ground pin GND in an equal potential; the output ends of the third amplifier K3, the fourth amplifier K4 and the fifth amplifier K5 are respectively connected with the oscillation control module.
Optionally, the battery protection chip further includes a charging control circuit, and the charging control circuit is connected to the output control module and the detection pin CS.
The charging control circuit is used for charging the 0V battery. In particular, it can be used to recharge batteries that have self-discharged to 0V. When the charger voltage connected between the battery anode B + and the battery cathode B-is higher than the charger starting voltage VOV for charging the 0V battery, the grid electrode of the first field effect transistor Q1 for charge control is fixed to the voltage of the VDD pin, and the voltage difference between the grid electrode and the source electrode of the first field effect transistor Q1 is higher than the conducting voltage due to the charger voltage, so that the first field effect transistor Q1 for charge control is turned on to start charging. The second fet Q2 is still off, and the charging current flows through its internal parasitic diode. And when the battery voltage VCC is higher than the overdischarge detection voltage VODP, entering a normal working state.
Optionally, the source first port S1 of the first field effect transistor Q1 is respectively connected to the negative electrode of the lithium battery pack, the output end of the first capacitor C1, and the ground pin GND of the battery protection chip;
a second source port S2 of the first field effect transistor Q1 is respectively connected with an output port P-of the second resistor R2 and an output port P-of a load;
the drain electrode first port D1 of the first field effect transistor Q1 is connected with the drain electrode second port of the first field effect transistor Q1;
a gate first port G1 of the first field effect transistor Q1 is connected with the over-discharge protection control pin OD; the gate second port G2 of the first field effect transistor Q1 is connected to the overcharge protection control pin OC.
Optionally, the source first port S2 of the second field effect transistor Q2 is respectively connected with the output port of the second resistor R2 and the output port P-of the load;
a second port of a source electrode of the second field effect transistor Q2 is respectively connected with a negative electrode of the lithium battery pack, an output end of the first capacitor and a grounding pin of the battery protection chip;
the drain first port D1 of the second field effect transistor Q2 is connected with the drain first port D1 and the drain second port D2 of the first field effect transistor Q1;
a gate second port G2 of the second field effect transistor Q2 is connected to the over-discharge protection control pin OD; the gate first port G1 of the second field effect transistor Q2 is connected to the overcharge protection control pin OC.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
Claims (8)
1. A lithium battery protection circuit, comprising: the device comprises a lithium battery pack, a battery protection module and a charge and discharge control module; the battery protection module comprises a first resistor, a first capacitor, a second resistor and a battery protection chip; the charge and discharge control module comprises a first field effect tube and a second field effect tube; the lithium battery protection circuit also comprises a load input end and a load output end which are used for connecting a load; wherein the content of the first and second substances,
the input end of the first resistor is connected with the anode of the lithium battery pack, and the input end of the first resistor is also connected with the load input end;
the output end of the first resistor is connected with the battery protection chip, and the output end of the first resistor is also connected with the input end of the first capacitor;
the output end of the first capacitor is connected with the battery protection chip; the output end of the first capacitor is also connected with the negative electrode of the lithium battery pack; the output end of the first capacitor is also connected with the charge and discharge control module;
the input end of the second resistor is connected with the battery protection chip; the output end of the second resistor is connected with the charge and discharge control module; the output end of the second resistor is also connected with the load output end;
the anode of the lithium battery pack is connected with the load input end; the charge and discharge control module is connected with the load output end; and the charge and discharge control module is connected with the negative electrode of the lithium battery pack.
2. The circuit of claim 1, wherein the battery protection module further comprises a third resistor, and an input end of the third resistor is connected with an external temperature detection device; the output end of the third resistor is connected with the charge and discharge control module; the third resistor is also connected with the load output end.
3. The circuit of claim 1 or 2, wherein the battery protection chip comprises: the system comprises an overcharge/discharge detection circuit, an oscillation control module, a frequency division control module, an output control module, a short circuit detection module, an overcurrent detection module and a charge detection module; the battery protection chip further includes: an over-discharge protection control pin, a detection pin, an over-charge protection control pin, a blank pin, a power supply pin and a grounding pin; wherein the content of the first and second substances,
the overcharge/discharge detection circuit is respectively connected with the power supply pin and the grounding pin; the overcharge/discharge detection circuit is also connected with the oscillation control module;
the oscillation control module is also connected with the short circuit detection module, the overcurrent detection module, the charging detection module and the frequency division control module;
the frequency division control module is also connected with the output control module;
the output control module is respectively connected with the over-discharge protection control pin and the over-charge protection control pin;
the short circuit detection module, the overcurrent detection module and the charging detection module are also connected with the detection pins;
the power supply pin is connected with the output end of the first resistor and the input end of the first capacitor;
the grounding pin is connected with the output end of the first capacitor and the negative electrode of the lithium battery pack;
the overdischarge protection control pin is connected with the first field effect transistor; the overcharge protection control pin is connected with the second field effect transistor;
the detection pin is connected with the input end of the second resistor.
4. The circuit of claim 3, wherein the overcharge/discharge detection circuit comprises an overcharge detection resistor, a first variable resistor, a first amplifier, an overdischarge detection resistor, a second variable resistor, a second amplifier, and a first power supply; wherein the content of the first and second substances,
one end of the first variable resistor is connected with the power supply pin and one section of the second variable resistor; the other end of the first variable resistor is connected with one end of the overcharge detection resistor and the positive input end of the first amplifier;
the other end of the overcharge detection resistor is connected with the grounding pin and the negative electrode of the first power supply;
the other end of the second variable resistor is connected with one end of the over-discharge detection resistor and the positive electrode input end of the second amplifier;
the other end of the over-discharge detection resistor is connected with the grounding pin and the negative electrode of the first power supply;
the anode of the first power supply is respectively connected with the cathode input end of the first amplifier and the cathode input end of the second amplifier;
the output end of the first amplifier and the output end of the second amplifier are respectively connected with the oscillation control module.
5. The circuit of claim 4, wherein the short detection module comprises a third amplifier and a second power supply, and wherein a positive input of the third amplifier is connected to a positive terminal of the second power supply; the negative electrode input end of the third amplifier is connected with the detection pin;
the overcurrent detection module comprises a fourth amplifier and a third power supply, and the positive electrode input end of the fourth amplifier is connected with the positive electrode of the third power supply; the negative electrode input end of the fourth amplifier is connected with the detection pin;
the charging detection module comprises a fifth amplifier and a fourth power supply, and the positive electrode input end of the fifth amplifier is connected with the positive electrode of the fourth power supply; the negative electrode input end of the fifth amplifier is connected with the detection pin;
the negative electrodes of the second power supply, the third power supply and the fourth power supply are connected with the grounding pin in an equipotential manner; and the output ends of the third amplifier, the fourth amplifier and the fifth amplifier are respectively connected with the oscillation control module.
6. The circuit of claim 5, wherein the battery protection chip further comprises a charge control circuit, and the charge control circuit is connected to the output control module and the detection pin.
7. The circuit according to any one of claims 4-6, wherein the first source port of the first FET is connected to the negative electrode of the lithium battery pack, the output terminal of the first capacitor, and the ground pin of the battery protection chip, respectively;
a second port of the source electrode of the first field effect transistor is respectively connected with an output port of the second resistor and an output port of the load;
a first port of a drain electrode of the first field effect transistor is connected with a second port of the drain electrode of the first field effect transistor;
a first gate port of the first field effect transistor is connected with the overdischarge protection control pin; and a second gate port of the first field effect transistor is connected with the overcharge protection control pin.
8. The circuit of claim 7, wherein the first source port of the second fet is connected to the output port of the second resistor and the output port of the load, respectively;
a second port of a source electrode of the second field effect transistor is respectively connected with a negative electrode of the lithium battery pack, an output end of the first capacitor and a grounding pin of the battery protection chip;
the first port of the drain electrode of the second field effect transistor is connected with the first port of the drain electrode and the second port of the drain electrode of the first field effect transistor;
a second gate port of the first field effect transistor is connected with the overdischarge protection control pin; and a first gate port of the first field effect transistor is connected with the overcharge protection control pin.
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| CN202021640173.7U CN212518490U (en) | 2020-08-07 | 2020-08-07 | Lithium battery protection circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| TWI759238B (en) * | 2021-07-22 | 2022-03-21 | 華碩電腦股份有限公司 | Battery apparatus and battery protection method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| TWI759238B (en) * | 2021-07-22 | 2022-03-21 | 華碩電腦股份有限公司 | Battery apparatus and battery protection method thereof |
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