CN213243575U

CN213243575U - Battery protection circuit

Info

Publication number: CN213243575U
Application number: CN202021552610.XU
Authority: CN
Inventors: 臧传美
Original assignee: Zhejiang Aerlang Technology Co Ltd
Current assignee: Zhejiang Aerlang Technology Co Ltd
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2021-05-18
Anticipated expiration: 2030-07-30

Abstract

The utility model discloses a battery protection circuit, relate to the electron technical field, this circuit includes that voltage judges the processing unit, the locking unit charges, first switch drive unit, second switch drive unit, overcurrent protection unblock unit and overcurrent protection unit, under-voltage at the battery, battery charging and battery discharge judge the processing unit through voltage respectively when overflowing, the locking unit that charges cuts off the discharge route with the first switch drive unit of overcurrent protection unit control, judge through voltage when the battery is excessive pressure that processing unit control second switch drive unit cuts off the charge route, accomplish to trun into when discharging through overcurrent protection unblock unit control overcurrent protection unit output and do not have overcurrent signal to first switch drive unit and then trigger first switch drive unit and open the discharge route, make the battery can be for external load stable power supply. The circuit effectively protects the safety, stability and reliability of the battery under various conditions in a hardware mode, and is simple and low in cost.

Description

Battery protection circuit

Technical Field

The utility model relates to the field of electronic technology, especially, relate to a battery protection circuit.

Background

The electric balance car mainly comprises a single wheel and two wheels, the operation principle of the electric balance car is mainly established on Dynamic Stabilization (Dynamic Stabilization), a gyroscope and an acceleration sensor inside the car body are used for detecting the change of the posture of the car body, a servo control system is used for accurately driving a motor to perform corresponding adjustment so as to keep the balance of the car body, and the electric balance car is a novel green product used by modern people as a walking tool and leisure and entertainment.

With the improvement of safety requirements of the balance car, the rechargeable battery is also required to have a higher-level safety function as a power source of the balance car. When the battery is in an overcurrent state in the discharging process, the overcurrent protection unit is usually used for controlling the cut-off of the discharging path so as to ensure the safety of the battery, and in practical application, when the battery is charged and is disconnected from the charger and then is connected with the balance car for discharging, the battery discharging interface can receive a period of high level to trigger the opening and locking of the overcurrent protection function, the battery discharging path is cut off, and the overcurrent protection cannot be automatically unlocked, so that the battery cannot stably supply power for the balance car.

SUMMERY OF THE UTILITY MODEL

In order to overcome the deficiency of the prior art, one of the purposes of the utility model is to provide a battery protection circuit, it is through overcurrent protection unblock unit with hardware form control overcurrent protection unit output do not have overcurrent signal to first switch drive unit and then trigger first switch drive unit and open the discharge path between battery negative pole and the burden interface that discharges, make the battery can be for the stable power supply of external load, safe and reliable.

The utility model discloses an one of the purpose adopts following technical scheme to realize:

a battery protection circuit comprising:

the first end and the second end of the voltage judgment processing unit are respectively connected to the positive electrode and the negative electrode of the battery, and the third end and the fourth end of the voltage judgment processing unit are respectively connected with the first switch driving unit and the second switch driving unit;

the first end of the charging locking unit is connected to the charging negative interface, and the second end of the charging locking unit is connected with the first switch driving unit;

the first end and the second end of the first switch driving unit are respectively connected to the negative electrode of the battery and the discharging negative interface, the third end of the first switch driving unit is connected with the voltage judgment processing unit, and the fourth end of the first switch driving unit is connected with the charging locking unit and the overcurrent protection unit;

the first end and the second end of the second switch driving unit are respectively connected to the negative electrode of the battery and the charging negative interface, and the third end of the second switch driving unit is connected with the voltage judgment processing unit;

the first end and the second end of the overcurrent protection unlocking unit are respectively connected to the positive electrode of the battery and the charging negative interface, and the third end of the overcurrent protection unlocking unit is connected with the overcurrent protection unit;

the first end of the overcurrent protection unit is connected to the discharging negative interface, and the second end and the third end of the overcurrent protection unit are respectively connected with the overcurrent protection unlocking unit and the first switch driving unit;

the overcurrent protection unlocking unit outputs an unlocking signal to the overcurrent protection unit when the battery is disconnected from charging and supplies power to a load, the overcurrent protection unit outputs a no overcurrent signal to the first switch driving unit when receiving the unlocking signal, and the first switch driving unit opens a discharging passage between the negative electrode of the battery and the discharging negative interface when receiving the no overcurrent signal.

Further, still include:

and the first end of the charging port electrification preventing unit is connected with the second switch driving unit, and the second end of the charging port electrification preventing unit is connected with the charging negative interface and is configured to close a path between the charging negative interface and the negative electrode of the battery in a normal discharging process.

Further, still include:

the current detection unit is connected with the negative electrode of the battery at a first end, connected with the first switch driving unit and the second switch driving unit at a second end, and configured to output a voltage signal to the first switch driving unit and the second switch driving unit when the charging current or the discharging current of the battery is detected so as to enable the first switch driving unit and the second switch driving unit to be switched on or switched off.

Further, the first switch driving unit includes:

a first driving unit, a first end of which is connected to the voltage judgment processing unit, a second end of which is connected to the first switching unit, and configured to output a first level to the first switching unit when receiving the signal output from the voltage judgment processing unit;

and the first end of the first switch unit is connected with the first driving unit, the charging locking unit and the overcurrent protection unit, and the second end and the third end of the first switch unit are respectively connected to the negative electrode of the battery and the discharging negative interface, so that the first switch unit is configured to open a discharging path between the negative electrode of the battery and the discharging negative interface when receiving the no overcurrent signal or disconnect the discharging path between the negative electrode of the battery and the discharging negative interface when receiving the overcurrent signal output by the overcurrent protection unit or the first level or the locking signal output by the charging locking unit.

Further, the second switch driving unit includes:

a second driving unit, a first end of which is connected to the voltage judgment processing unit, a second end of which is connected to the second switch unit, and configured to output a second level to the second switch unit when receiving the signal output from the voltage judgment processing unit;

and the first end of the second switch unit is connected with the second driving unit, the second end and the third end of the second switch unit are respectively connected with the negative electrode of the battery and the charging negative interface, and the second switch unit is configured to disconnect a charging path between the negative electrode of the battery and the charging negative interface when receiving the second level.

Further, the first driving unit includes: the circuit comprises a first current limiting resistor, an RC filter circuit, a first pull-down resistor, a first triode, a first diode and a first pull-up resistor;

the first current limiting resistor is connected between the third end of the voltage judging and processing unit and the RC filter circuit in series;

the first pull-down resistor is connected between the base electrode of the first triode and the emitting electrode of the first triode;

the RC filter circuit is connected between the base electrode of the first triode and the emitting electrode of the first triode;

a collector of the first triode is connected to the positive electrode of the battery through the first pull-up resistor, and the collector of the first triode is connected with the first end of the first switch unit;

the first diode is connected between the emitter of the first triode and the collector of the first triode;

the first switching unit includes: the source electrode of each MOS tube is connected with the negative electrode of the battery, the drain electrode of each MOS tube is connected with the negative discharging interface, and the grid electrode of each MOS tube is connected with the second end of the charging locking unit, the second end of the first driving unit and the third end of the overcurrent protection unit.

Further, the second driving unit includes: the second current limiting resistor, the second diode, the second pull-down resistor, the second triode, the second pull-up resistor and the third diode;

the second current limiting resistor is connected between the fourth end of the voltage judging and processing unit and the anode of the second diode;

the cathode of the second diode is connected with the base electrode of the second triode;

the second pull-down resistor is connected between the base electrode of the second triode and the emitting electrode of the second triode;

the third diode is connected between the collector of the second triode and the emitter of the second triode;

a collector of the second triode is connected with the positive electrode of the battery through the second pull-up resistor, and the collector of the second triode is connected with the first end of the second switch unit;

the second switching unit includes: the drain electrode of each MOS tube is connected with the cathode of the battery, the source electrode of each MOS tube is connected with the charging negative interface, and the grid electrode of each MOS tube is connected with the second end of the second driving unit.

Further, the charge lock unit includes: the fourth diode, the third current-limiting resistor, the third pull-up resistor and the third triode;

the cathode of the fourth diode is connected with a charging negative interface, and the anode of the fourth diode is connected to the base electrode of the third triode through the third current-limiting resistor;

the third pull-up resistor is connected between an emitter of the third triode and a base of the third triode, the emitter of the third triode is connected with the fourth end of the first switch driving unit, and a collector of the third triode is grounded.

Further, the overcurrent protection unlocking unit includes: the optical coupler OC1, a fourth current-limiting resistor, a first voltage-dividing resistor and an energy-storage capacitor;

a first input pin of the optical coupler OC1 is connected to the positive pole of the battery through the fourth current-limiting resistor, a second input pin of the optical coupler OC1 is connected to a charging negative interface, and the first voltage-dividing resistor is connected between the first input pin and the second input pin of the optical coupler OC 1;

the energy storage capacitor is connected between the anode of the battery and the second input pin of the optical coupler OC 1;

a first output pin of the optical coupler OC1 is grounded, and a second output pin of the optical coupler OC1 is connected with a second end of the overcurrent protection unit.

Further, the overcurrent protection unit includes: a fifth current limiting resistor, a second voltage dividing resistor, a third pull-down resistor and a fourth triode;

the fifth current-limiting resistor is connected between the discharging negative interface and the base electrode of the fourth triode;

the second voltage-dividing resistor is connected between the discharge negative interface and the emitter of the fourth triode;

the third pull-down resistor is connected between the base electrode and the emitting electrode of the fourth triode;

the base electrode of the fourth triode is connected with the third end of the overcurrent protection unlocking unit, the collector electrode of the fourth triode is connected with the fourth end of the first switch driving unit, and the emitter electrode of the fourth triode is connected to the negative electrode of the battery.

Compared with the prior art, the beneficial effects of the utility model reside in that:

the utility model discloses accomplish to trun into when discharging to through overcurrent protection unblock unit with hardware form control overcurrent protection unit output through battery charging and do not have overcurrent signal to first switch drive unit and then trigger first switch drive unit and open the discharge path between battery negative pole and the negative interface that discharges, make the battery can be for the stable power supply of external load, safe and reliable.

Drawings

Fig. 1 is a schematic diagram of a battery protection circuit according to a first embodiment of the present invention;

fig. 2 is a schematic circuit diagram of a charging locking unit according to a second embodiment of the present invention;

fig. 3 is a schematic circuit diagram of an overcurrent protection unlocking unit in the third embodiment of the present invention;

fig. 4 is a schematic circuit diagram of an overcurrent protection unit according to a third embodiment of the present invention;

fig. 5 is a schematic circuit diagram of a voltage determination processing unit according to a fourth embodiment of the present invention;

fig. 6 is a schematic circuit diagram of a first driving unit according to a fifth embodiment of the present invention;

fig. 7 is a schematic circuit diagram of a first switch unit according to a fifth embodiment of the present invention;

fig. 8 is a schematic structural diagram of a battery protection circuit according to a sixth embodiment of the present invention;

fig. 9 is a schematic circuit diagram of a second driving unit and a second switching unit according to a sixth embodiment of the present invention;

fig. 10 is a schematic structural diagram of a battery protection circuit according to a seventh embodiment of the present invention;

fig. 11 is a schematic circuit diagram of a charging port electrification preventing unit according to a seventh embodiment of the present invention.

Wherein: 80. an overcurrent protection unit; 90. an overcurrent protection unlocking unit; 100. a voltage judgment processing unit; 110. a charging lock unit; 120. a first switch driving unit; 130. a second switch driving unit; 140. A voltage judging unit; 150. a judgment signal processing unit; 160. a processing subunit; 170. a first drive unit; 180. a first switch unit; 190. a second driving unit; 200. a second switching unit; 210. a charging port electrification preventing unit; 220. a current detection unit; b +, battery positive pole; b-, a battery cathode; p +, positive discharge interface; p-, a discharging negative interface; c +, charging positive interface; c-, a charging negative interface.

Detailed Description

The present invention will now be described in more detail with reference to the accompanying drawings, and it is to be understood that the following description of the present invention is made only by way of illustration and not by way of limitation with reference to the accompanying drawings. The current limiting resistor, the pull-up resistor, the pull-down resistor and the voltage dividing resistor in each embodiment are all resistor networks, and may be one resistor element, or may be a circuit formed by connecting a plurality of resistor elements with different and/or same resistance values in series and/or in parallel. The energy storage capacitor in each embodiment is a capacitor network, and may be a capacitor element, or a circuit in which a plurality of capacitor elements having different and/or the same capacitance values are connected in series and/or in parallel. The chip model and the pins in the various embodiments can be adjusted according to the needs. Some units in various embodiments also have power supply ports, and power supply of the units is provided by the battery in the scheme, and the power supply positive pole and the power supply negative pole of the units are respectively connected with the battery positive pole and the battery negative pole, namely, the grounding of each unit in various embodiments means that the battery negative pole is connected. The various embodiments may be combined with each other to form other embodiments not shown in the following description.

Example one

The embodiment I provides a battery protection circuit, which aims to control an overcurrent protection unit 80 to output a no-overcurrent signal to a first switch driving unit 120 to trigger the first switch driving unit 120 to open a discharge path between a battery cathode B and a discharge negative interface P through an overcurrent protection unlocking unit 90 in a hardware mode, effectively protects the safety of a battery, is stable and reliable, has a simple circuit and low cost, and solves the problem that the overcurrent protection function cannot be unlocked when charging is completed and power is supplied to a load.

The first switch driving unit 120 is controlled by the charge locking unit 110 in a hardware manner to rapidly cut off the discharging path when the battery is charged, and the voltage judgment processing unit 100 triggers the first switch driving unit 120 in a hardware manner to cut off the discharging path or triggers the second switch driving unit 130 to cut off the charging path when the battery is under-voltage or over-voltage.

Referring to fig. 1, a battery protection circuit includes: the charging device comprises a voltage judgment processing unit 100, a charging locking unit 110, a first switch driving unit 120, a second switch driving unit 130, an overcurrent protection unlocking unit 90 and an overcurrent protection unit 80.

The first terminal and the second terminal of the voltage determination processing unit 100 are respectively connected to the battery anode B + and the battery cathode B-, and the third terminal and the fourth terminal thereof are respectively connected to the first switch driving unit 120 and the second switch driving unit 130. The first terminal of the charging locking unit 110 is connected to the charging negative interface C-, and the second terminal thereof is connected to the first switch driving unit 120. The first switch driving unit 120 has a first terminal and a second terminal respectively connected to the battery negative electrode B-and the discharging negative interface P-, a third terminal connected to the voltage determination processing unit 100, and a fourth terminal connected to the charging locking unit 110 and the overcurrent protection unit 80. The first terminal and the second terminal of the second switch driving unit 130 are respectively connected to the battery negative electrode B-and the charging negative interface C-, and the third terminal thereof is connected to the voltage judgment processing unit 100. The first end and the second end of the overcurrent protection unlocking unit 90 are respectively connected to the battery anode B + and the charging negative interface C-, and the third end of the overcurrent protection unlocking unit is connected with the overcurrent protection unit 80. A first end of the over-current protection unit 80 is connected to the discharging negative interface P-, and a second end and a third end thereof are respectively connected to the over-current protection unlocking unit 90 and the first switch driving unit 120.

When the battery is disconnected from the charger after charging is completed and the battery is connected with the load and discharged, the charging negative interface C-is changed from a low level to be suspended, the discharging negative interface P-has a high level for a period of time, the overcurrent protection unlocking unit 90 outputs an unlocking signal to the overcurrent protection unit 80, the overcurrent protection unit 80 outputs a no overcurrent signal to the first switch driving unit 120 when receiving the unlocking signal, the first switch driving unit 120 opens a discharging path between the battery negative electrode B-and the discharging negative interface P-when receiving the no overcurrent signal, so that the battery can stably supply power for the external load, the discharging negative interface P-is changed into a low level, the locked overcurrent protection function of the overcurrent protection unit 80 is released, and the overcurrent protection unit 80 recovers normal overcurrent detection work.

When the battery is in an overcurrent discharging process, the discharging negative interface P-is in a high level, the overcurrent protection unit 80 outputs an overcurrent signal to the first switch driving unit 120, so that the first switch driving unit 120 cuts off a discharging path between the battery cathode B-and the discharging negative interface P-, the battery is ensured not to cause potential safety hazards due to overcurrent, and the safety is improved.

When the battery is charged, the charging negative interface C-is at a low level, and the charging locking unit 110 outputs a locking signal to the first switch driving unit 120. The first switch driving unit 120 disconnects a discharge path between the battery negative electrode B-and the discharge negative interface P-upon receiving the lock-up signal. The circuit is effectively protected. The first switch driving unit 120 is controlled by the charging locking unit 110 in a hardware manner to rapidly cut off a battery discharging path when the battery is charged, so that the danger of short circuit of a battery discharging loop can not be caused even if the discharging interface has external interference, the safety of the battery is effectively protected, the operation is stable and reliable, and the power supply unit is not required to supply power for the charging locking unit 110 independently.

The voltage determination processing unit 100 outputs a signal to the first switch driving unit 120 or/and the second switch driving unit 130 according to the battery voltage. The voltage determination processing unit 100 outputs a level signal to the first switch driving unit 120 when the battery voltage is lower than a first threshold voltage, or outputs a level signal to the second switch driving unit 130 when the battery voltage is higher than a second threshold voltage. The first switch driving unit 120 disconnects a discharge path between the battery negative electrode B-and the discharge negative interface P-upon receiving the level signal output from the voltage determination processing unit 100. The second switch driving unit 130 disconnects the charging path between the battery negative electrode B-and the charging negative interface C-upon receiving the level signal output from the voltage determination processing unit 100. When the battery is under-voltage or over-voltage, the voltage judgment processing unit 100 triggers the first switch driving unit 120 to cut off the discharging path or triggers the second switch driving unit 130 to cut off the charging path in a hardware mode, so that the safety of the battery is protected.

Specifically, when the voltage determination processing unit 100 detects that the cell voltage in the battery is lower than the first threshold voltage 2.30V during the discharging process of the battery, a level signal is output to the first switch driving unit 120, and the first switch driving unit 120 cuts off a discharging path between the battery negative electrode B-and the discharging negative interface P-. In the charging process of the battery, when the voltage judgment processing unit 100 detects that the cell voltage in the battery is higher than the second threshold voltage by 4.35V, a level signal is output to the second switch driving unit 130, and the second switch driving unit 130 cuts off a charging path between the battery cathode B-and the charging negative interface C-, so that potential safety hazards caused by overvoltage of the battery are avoided, and the safety is improved. In other embodiments, the first threshold voltage and the second threshold voltage may have other voltage values.

Example two

The second embodiment is an improvement on the first embodiment, and the charging locking unit 110 includes a fourth diode, a third current limiting resistor, a third pull-up resistor, and a third triode. The cathode of the fourth diode is connected with the charging negative interface C-, and the anode of the fourth diode is connected to the base electrode of the third triode through the third current limiting resistor; the third pull-up resistor is connected between the emitter of the third triode and the base of the third triode, the emitter of the third triode is connected to the fourth terminal of the first switch driving unit 120, and the collector of the third triode is grounded.

In this embodiment, the fourth diode in the charging locking unit 110 is a diode D10, the third current-limiting resistor is a resistor R20, the third pull-up resistor is a resistor R21, and the third transistor is a transistor D11, as shown in fig. 2, the cathode of the diode D10 is connected to the charging negative interface C-, the anode of the diode D10 is connected to one end of a resistor R20, one end of the resistor R21 and the base of the transistor D11 are both connected to the other end of the resistor R20, the emitter of the transistor D11 and the other end of the resistor R21 are both connected to the fourth end of the first switch driving unit 120, and the collector of the transistor D11 is grounded.

When the battery is connected with the charger for charging, the charging negative interface C-is at a low level, the diode D10 is turned on, so that the transistor D11 is turned on, and the emitter of the transistor D11 outputs a low level, that is, the first level output from the output DO terminal of the charging locking unit 110 to the first switch driving unit 120 is a low level, so that the first switch driving unit 120 cuts off the discharging path of the battery, and the operation is stable and reliable.

EXAMPLE III

The third embodiment is an improvement on the first embodiment or the second embodiment, when the battery is charged and discharged, the overcurrent protection unlocking unit 90 controls the overcurrent protection unit 80 to output a no-overcurrent signal to the first switch driving unit 120 in a hardware form to trigger the first switch driving unit 120 to open a discharge path between the battery cathode B and the discharge negative interface P, so that the battery can stably supply power for an external load, and the battery is safe and reliable.

The overcurrent protection unlocking unit 90 comprises an optocoupler OC1, a fourth current limiting resistor, a first voltage dividing resistor and an energy storage capacitor. A first input pin of the optical coupler OC1 is connected to the battery anode B + through a fourth current-limiting resistor, a second input pin of the optical coupler OC1 is connected to the charging negative interface C-, and a first voltage-dividing resistor is connected between the first input pin and the second input pin of the optical coupler OC 1; the energy storage capacitor is connected between the battery anode B + and a second input pin of the optical coupler OC 1; a first output pin of the optical coupler OC1 is grounded, and a second output pin of the optical coupler OC1 is connected with a second end of the overcurrent protection unit 80.

In this embodiment, the fourth current-limiting resistor in the overcurrent protection unlocking unit 90 is a resistor R22, the first voltage-dividing resistor is a resistor R23, and an energy storage capacitor is composed of a capacitor C13 and a capacitor C14, as shown in fig. 3, a pin 2 of the optocoupler OC1 and one end of the resistor R23 are both connected to the charging negative interface C-, the other end of the resistor R23 and one end of the resistor R22 are both connected to a pin 1 of the optocoupler OC1, the other end of the resistor R22 is connected to the battery anode B +, the capacitor C13 and the capacitor C14 are connected in series between the battery anode B + and a pin 2 of the optocoupler OC1, a pin 4 of the optocoupler OC1, that is, a third end (DO _ LOCK end) of the overcurrent protection unlocking unit 90 is connected to the second end of the overcurrent protection unit 80. When the charging negative interface C-is changed from a low level to a suspension state, the resistor R22 and the resistor R23 can play a role in releasing charges on the capacitor C13 and the capacitor C14, so that the resistor R22, the resistor R23, the capacitor C13 and the capacitor C14 form a discharge loop, and the pin 1 of the optocoupler OC1 generates a high level for a certain time, so that the pin 4 of the optocoupler OC1 maintains a low level for a certain time, that is, the DO _ LOCK end also maintains a low level for a certain time. The optical coupler OC1 has an isolation effect, the input end and the output end are completely electrically isolated, an output end signal has no influence on the input end, the anti-interference capability is strong, and the work is stable.

The overcurrent protection unit 80 includes a fifth current-limiting resistor, a second voltage-dividing resistor, a third pull-down resistor, and a fourth triode; the fifth current-limiting resistor is connected between the discharging negative interface P-and the base electrode of the fourth triode; the second voltage-dividing resistor is connected between the discharging negative interface P-and the emitter of the fourth triode; the third pull-down resistor is connected between the base electrode and the emitting electrode of the fourth triode; the base of the fourth triode is connected with the third end of the overcurrent protection unlocking unit 90, the collector of the fourth triode is connected with the fourth end of the first switch driving unit 120, and the emitter of the fourth triode is connected with the cathode B-of the battery.

In this embodiment, the fifth current-limiting resistor in the overcurrent protection unit 80 is a resistor R16, the second voltage-dividing resistor is a resistor R17, the third pull-down resistor is a resistor R18, and the fourth triode is a triode D6, as shown in fig. 4, one end of the resistor R16 and one end of the resistor R17 are connected to the P- (D) terminal of the negative discharge interface, the other end of the resistor R16, one end of the resistor R18, and the base of the triode D6 are connected to the DO _ LOCK terminal and to the third terminal of the overcurrent protection unlocking unit 90, the other end of the resistor R17, the other end of the resistor R18, and the emitter of the triode D6 are connected to the battery negative electrode B-, and the collector of the triode D6 is connected to the fourth terminal of the.

When the battery is charged and disconnected from the charger and the battery is connected with the charger and discharged, the charging negative interface C-is changed from a low level to a floating state, charges are stored in the capacitor C13 and the capacitor C14, the resistor R22 and the resistor R23 can play a role of releasing the charges on the capacitor C13 and the capacitor C14, the resistor R22, the resistor R23, the capacitor C13 and the capacitor C14 form a discharge loop, the pin 1 of the optocoupler OC1 generates a high level for a certain time, the light-emitting ends (namely the pin 1 and the pin 2) of the optocoupler OC1 can be maintained to be turned on within a period of time, the optocoupler OC1 is delayed to be turned off, the light-receiving end of the optocoupler OC1 is also turned on within a period of time (namely the pin 3 and the pin 4), the pin 4 of the optocoupler OC1 maintains a low level for a certain time, namely the DO _ LOCK end outputs a low-level unlocking signal to the overcurrent protection unit 80, the triode D6 in the overcurrent protection unit 80 is turned off, and the collector of the triode D6 outputs a no And after the low-level unlocking signal maintaining time is over, the discharging path of the battery is normal, the overcurrent protection unit 80 continues to output no overcurrent signals to keep the battery discharging normally, and further, the external load is stably supplied with power, and the safety and the reliability are realized.

Example four

The fourth embodiment is an improvement on the basis of the third embodiment, the voltage determining unit 140 detects the voltages of the corresponding battery cells, and when any one of the battery cells in the battery is overvoltage, the first switch driving unit 120 is triggered to cut off the charging path of the battery, or when the battery cell is undervoltage, the second switch driving unit 130 is triggered to cut off the discharging path, so that the safety of the battery is effectively protected. The voltage judging unit 140 only needs to compare the voltage magnitude and output a low level signal, and does not need to process data, so that programming is not needed, and no working method or improvement thereof is involved.

Referring to fig. 5, the voltage determination processing unit 100 includes a plurality of voltage determination units 140 and a determination signal processing unit 150, the battery includes a plurality of electrically connected cells, the number of the voltage determination units 140 corresponds to the number of the cells, each voltage determination unit 140 is correspondingly connected to one cell, the determination signal processing unit 150 includes processing sub-units 160 corresponding to the number of the cells, and each processing sub-unit 160 corresponds to the voltage determination unit 140 of one cell. The voltage determination unit 140 is configured to detect a cell voltage and output a low level signal to the corresponding processing subunit 160 when the cell voltage is lower than a first threshold voltage or higher than a second threshold voltage.

Taking one voltage determination unit 140 and the corresponding processing subunit 160 as an example, the voltage determination unit 140 includes a chip U1, a resistor R1, a capacitor C1, a resistor R14, and a resistor R15, one end of the resistor R1 is connected to the positive electrode of the cell, the other end of the resistor R1 is connected to the VDD pin 5 of the chip U1 and one end of the capacitor C1, the other end of the capacitor C1 is connected to the negative electrode of the cell and the VSS pin 6 of the chip U1, the CO pin 3 of the chip U1 is connected to the input end of the corresponding processing subunit 160 through the resistor R15, the DO pin 1 of the chip U1 is connected to the input end of the corresponding processing subunit 160 through the resistor R14, and the chip U1 detects a voltage between the VDD pin 5 and the VSS pin 6, that is a cell voltage. In other embodiments, the VM pin 2 of the chip U1 may be connected to the current detection unit via the resistor R40, and the chip U1 outputs a voltage signal to the second switch driving unit 130 to cut off the battery charging path when detecting the voltage variation of the current detection unit. When the current detection unit 220 detects an overcurrent or a charger is connected, it may output a signal to the processing sub-unit 160, or directly output the signal to the first switch driving unit 120 or the second switch driving unit 130. When the current detection unit 220 detects that the current is abnormal, signals are output to the processing subunit 160 through the CO pin 3 and the DO pin 1 of the chip U1.

The corresponding processing subunit 160 comprises a fifth current-limiting resistor R41, a sixth current-limiting resistor R54, a triode Q1 and a triode Q10, wherein the emitting electrodes of the triode Q1 and the triode Q10 are connected with the corresponding positive electrodes of the battery cells, the base electrode of the triode Q1 is connected with the CO pin 3 of the chip U1, the base electrode of the triode Q10 is connected with the DO pin 1 of the chip U1, the collector electrode of the triode Q1 is a CO signal end, and the collector electrode of the triode Q10 is a DO signal end. The average normal voltage of the battery cells is 3.7V, when the cell voltage is higher than the second threshold voltage of 4.35V, the CO pin 3 of the chip U1 outputs a low level signal to the input terminal of the corresponding processing subunit 160, and when the cell voltage is lower than the first threshold voltage of 2.30V, the DO pin 1 of the chip U1 outputs a low level signal to the input terminal of the corresponding processing subunit 160.

As shown in fig. 5, another voltage determination unit 140 is composed of a chip U2, a resistor R2, a capacitor C2, a resistor R16 and a resistor R17, and a processing subunit 160 corresponding thereto is composed of a seventh current-limiting resistor R42, an eighth current-limiting resistor R55, a transistor Q2 and a transistor Q11; the chip U3, the resistor R3, the capacitor C3, the resistor R18 and the resistor R19 form a third voltage determination unit 140, and the ninth current-limiting resistor R43, the tenth current-limiting resistor R56, the triode Q3 and the triode Q11 form a processing subunit 160 corresponding thereto; by analogy, the figure exemplarily includes ten voltage determination units 140 and corresponding processing sub-units 160. The CO signal terminal and the DO signal terminal of each processing subunit 160 are electrically connected to the All-CO signal terminal and the All-DO signal terminal through corresponding current limiting resistors, respectively, and the All-DO signal terminal and the All-CO signal terminal are used as the third terminal and the fourth terminal of the voltage determination processing unit 100 and are connected to the first switch driving unit 120 and the second switch driving unit 130, respectively. In an embodiment, the model of the chip in the voltage determination unit 140 may adopt DW 01.

When any one of the battery cells has a fault, the corresponding processing subunit 160 can output a signal to the first switch driving unit 120 through the third terminal of the voltage determination processing unit 100 to cut off a discharging path, or output a signal to the second switch driving unit 130 through the fourth terminal of the voltage determination processing unit 100 to cut off a charging path, so that the battery stops charging or discharging, the fault battery cell is prevented from being continuously damaged, and the fault battery cell and the whole circuit are effectively protected from being safe.

EXAMPLE five

The fifth embodiment is an improvement on the fourth embodiment, and the first switch driving unit 120 cuts off a discharging path in a hardware form when the battery is charged or discharged under-voltage or when the battery is over-current in the discharging process, so as to protect the safety of the battery.

The first switch driving unit 120 includes a first driving unit 170 and a first switching unit 180. The first driving unit 170 has a first terminal connected to the voltage determination processing unit 100, and a second terminal connected to the first switching unit 180, and is configured to output a first level to the first switching unit 180 when receiving a signal output from the voltage determination processing unit 100. The first switch unit 180 has a first end connected to the first driving unit 170, the charge locking unit 110 and the overcurrent protection unit 80, and a second end and a third end connected to the battery cathode B-and the discharge negative interface P-, respectively, and is configured to open a discharge path between the battery cathode B-and the discharge negative interface P-upon receiving no overcurrent signal, or to open a discharge path between the battery cathode B-and the discharge negative interface P-upon receiving an overcurrent signal or a first level output from the overcurrent protection unit 80 or a locking signal output from the charge locking unit 110.

The first driving unit 170 includes a first current limiting resistor, an RC filter circuit, a first pull-down resistor, a first triode, a first diode, and a first pull-up resistor. The first current limiting resistor is connected in series between the third terminal of the voltage judging and processing unit 100 and the RC filter circuit; the first pull-down resistor is connected between the base electrode of the first triode and the emitting electrode of the first triode; the RC filter circuit is connected between the base electrode of the first triode and the emitting electrode of the first triode; a collector of the first triode is connected to the battery anode B + through a first pull-up resistor, and the collector of the first triode is connected to the first end of the first switching unit 180; the first diode is connected between the emitter of the first triode and the collector of the first triode.

In this embodiment, the first current-limiting resistor is a resistor RQD1, an RC filter circuit is composed of a resistor R14, a capacitor C11, and a capacitor C12, the first pull-down resistor is a resistor R15, the first triode is a triode D4, the first diode is a diode D5, the first pull-up resistor is a resistor R13, as shown in fig. 6, one end of the resistor RQD1 is connected to the All-DO signal terminal of the voltage determination processing unit 100, the other end of the resistor RQD1 is connected to one end of a resistor R14, the other end of the resistor R14, one end of the resistor R15, one end of the capacitor C11, one end of the capacitor C12 is connected to the base of the triode D4, the other end of the resistor R15 is connected to the other, the other end of the capacitor C12, the emitter of the triode D4 and the anode of the diode D5 are connected with the cathode B-, the collector of the triode D4, the cathode of the diode D5 and one end of the resistor R13 are connected with the first switch unit 180, and the other end of the resistor R13 is connected with the anode B + of the battery. In other embodiments, the other end of the resistor R13 may be connected to the positive electrode of any cell of the battery to obtain a high voltage, so that the first switch unit 180 is in a conducting state under normal conditions of the battery.

The first switching unit 180 comprises at least one MOS transistor, a source electrode of each MOS transistor is connected with the battery cathode B-, a drain electrode of each MOS transistor is connected with the discharging negative interface P-, and a gate electrode of each MOS transistor is connected with the second end of the charging locking unit 110, the second end of the first driving unit 170 and the third end of the overcurrent protection unit 80. The parallel connection of a plurality of MOS tubes can reduce the current flowing through each MOS tube, and the device is safer. In other embodiments, the first switching unit 180 may be composed of other power switching devices such as IGBTs and thyristors, and the connection relationship of the power switching devices may also be adaptively changed.

In this embodiment, as shown in fig. 7, the first switch unit 180 includes an NMOS transistor Q1, an NMOS transistor Q2, and an NMOS transistor Q3 connected in parallel, a source of each NMOS transistor is connected to the battery negative electrode B-, a drain of each NMOS transistor is connected to the discharging negative interface P-, and a gate of each NMOS transistor is connected to the charging locking unit 110, the first driving unit 170, and the overcurrent protection unit 80.

When the battery is connected with the charger for charging, the charging cathode C-is changed to a low level, the second end of the charging locking unit 110 is changed to a low level, that is, the gate of the NMOS transistor in the first switch unit 180 is a low level, and the NMOS transistor is turned off, so that the discharging path is cut off, and the charging circuit is stable and reliable.

When the voltage of the battery cell is lower than the first threshold voltage in the discharging process of the battery, the DO pin 1 of the corresponding voltage judging unit 140 outputs a low level, the triode Q10 is turned on, the voltage of the battery cell anode B1 corresponding to the voltage judging unit 140 enables the ALL-DO signal end to have a high level through the turned-on triode Q10, the triode D4 in the first driving unit 170 is enabled to be switched on, the second end connected to the first switching unit 180 is pulled to the low level, the NMOS transistor in the first switching unit 180 is turned off, the discharging path is cut off when the battery cell is undervoltage, and the safety of the battery is effectively protected.

When the battery is in an overcurrent discharging process, the on-resistance of each MOS transistor in the first switch driving unit 120 is used as a detection basis, the collector of the triode D6 in the overcurrent protection unit 80 outputs a low-level overcurrent signal to the first switch driving unit 120, and the NMOS transistor in the first switch unit 180 is turned off, so that a discharging path is cut off during overcurrent, and the safety of the battery is effectively protected.

EXAMPLE six

The sixth embodiment is an improvement on the fourth or fifth embodiment, and the second switch driving unit 130 cuts off the charging path in a hardware manner when the battery is overcharged, so as to protect the battery.

Referring to fig. 8, the second switch driving unit 130 includes a second driving unit 190 and a second switch unit 200. The second driving unit 190 has a first terminal connected to the voltage determination processing unit and a second terminal connected to the second switching unit 200, and is configured to output a second level to the second switching unit 200 when receiving the signal output from the voltage determination processing unit 100. The second switching unit 200 has a first terminal connected to the second driving unit 190, and a second terminal and a third terminal respectively connected to the battery negative electrode B-and the charging negative interface C-, and is configured to disconnect a charging path between the battery negative electrode B-and the charging negative interface C-when receiving the second level.

The second driving unit 190 includes a second current limiting resistor, a second diode, a second pull-down resistor, a second transistor, a second pull-up resistor, and a third diode, and the second diode and the third diode may protect the second transistor. The second current limiting resistor is connected between the fourth end of the voltage judgment processing unit 100 and the anode of the second diode; the cathode of the second diode is connected with the base electrode of the second triode; the second pull-down resistor is connected between the base electrode of the second triode and the emitting electrode of the second triode; the third diode is connected with the collector electrode of the second triode and the emitter electrode of the second triode; the collector of the second triode is connected to the positive electrode B + of the battery through a second pull-up resistor, and the collector of the second triode is connected to the first terminal of the second switching unit 200.

In this embodiment, the second current-limiting resistor is a resistor RQC1, the second diode is a diode D2, the second pull-down resistor is a resistor R12, the second triode is a transistor D1, the second pull-up resistor is a resistor R11, and the third diode is a diode D3, as shown in fig. 9, one end of the resistor RQC1 is connected to the All-CO signal terminal of the voltage determination processing unit 100, the other end of the resistor RQC1 is connected to the anode of the diode D2, the cathode of the diode D2 and one end of the resistor R12 are connected to the base of the triode D1, the other end of the resistor R12, the emitter of the triode D1 and the anode of the diode D3 are connected to the charging negative interface C-, the collector of the triode D1, the cathode of the diode D3, one end of the resistor R11 is connected to the first end of the second switching unit 200, and the other end of the resistor. In other embodiments, the other end of the resistor R11 may be connected to the positive electrode of any cell of the battery to obtain a high voltage, so that the second switching unit 200 is in a conducting state under normal conditions of the battery.

The second switch unit 200 includes at least one MOS transistor, the drain of each MOS transistor is connected to the battery cathode B-, the source of each MOS transistor is connected to the charging negative interface C-, and the gate of each MOS transistor is connected to the second end of the second driving unit 190. As shown in fig. 8, the second switch unit 200 in this embodiment includes an NMOS transistor Q5, a drain of the NMOS transistor Q5 is connected to the battery negative B-, a source of the NMOS transistor Q5 is connected to the charging negative, and a gate of the NMOS transistor Q5 is connected to the second driving unit 190. In other embodiments, the second switching unit 200 may be composed of other power switching devices such as IGBTs and thyristors, and the connection relationship of the power switching devices may also be adaptively changed.

When the voltage of the battery cell is higher than the second threshold voltage in the battery charging process, the CO pin of the corresponding voltage judgment unit 140 outputs a low level, so that the triode Q1 is turned on, the voltage of the battery cell positive electrode B1 corresponding to the voltage judgment unit 140 enables the ALL-CO signal terminal to have a high level through the turned-on triode Q1, the ALL-CO signal terminal is connected with the first end of the second driving unit 190, the high level signal enables the triode D1 in the second driving unit 190 to be turned on, the second end connected to the second switch unit 200 is pulled to a low level, the NMOS transistor in the second switch unit 200 is turned off, the charging path is cut off when the battery cell is in overvoltage, and the battery is protected.

EXAMPLE seven

The seventh embodiment is an improvement on the above embodiments, and ensures the safety of the charging port and the battery during the discharging process by preventing the charging port charging unit 210 from ensuring that the charging port cannot output current during the normal discharging process.

Referring to fig. 10, the battery protection circuit further includes a charging port electrification preventing unit 210 having a first end connected to the second switch driving unit 130 and a second end connected to the charging negative interface C-configured to close a path between the charging negative interface C-and the battery negative electrode B-during a normal discharging process. The charging port electrification preventing unit 210 can prevent the charging port from being electrified, and reduce circuit loss.

The charging port electrification preventing unit 210 includes a plurality of diodes connected in parallel, an anode of each diode is connected to the second end of the second switch driving unit 130, a cathode of each diode is connected to the charging negative interface C-, and the plurality of diodes can be coupled to bear a larger current and perform a shunting function. As shown in fig. 11, the charging port electrification preventing unit 210 in this embodiment includes a diode D7, a diode D8, a diode D9, and a diode D18 connected in parallel, an anode of each diode is connected to the second end of the second switch driving unit 130, and a cathode of each diode is connected to the charging negative port C-.

In some other embodiments, the battery protection circuit further includes a current detection unit 220, a first terminal of which is connected to the battery cathode B-, and a second terminal of which is connected to the first switch driving unit 120 and the second switch driving unit 130, and configured to output a signal to the voltage determination processing unit 100 and output a voltage signal to the first switch driving unit 120 and the second switch driving unit 130 by the voltage determination processing unit 100 when the battery charging current or discharging current is detected, or directly output a voltage signal to the first switch driving unit 120 and the second switch driving unit 130, so as to turn on or off the first switch driving unit 120 and the second switch driving unit 130. The current detection unit 220 is used for detecting the current condition when the battery is charged or discharged, so as to accurately grasp the working state of the battery. In the case of the current detection unit 220, the first terminal of the overcurrent protection unit 80 may be connected to the current detection unit 220. Preferably, the current detection unit 220 is formed of a sampling resistor having a resistance of the order of milliohms.

It should be noted that, in the above embodiment, the first switch driving unit 120, the second switch driving unit 130, the charging locking unit 110, the overcurrent protection unit 80, the overcurrent protection unlocking unit 90, the charging port charging prevention unit 210, and the current detection unit 220 in the battery protection circuit are all disposed on the negative electrode side of the battery, and in other embodiments, the first switch driving unit 120, the second switch driving unit 130, the charging locking unit 110, the overcurrent protection unit 80, the overcurrent protection unlocking unit 90, the charging port charging prevention unit 210, and the current detection unit 220 are all disposed on the positive electrode side of the battery, which can also achieve the same technical effect.

It should be noted that, in the above embodiment of the battery protection circuit, each included unit is only divided according to functional logic, but is not limited to the above division as long as the corresponding function can be realized; in addition, the specific names of the functional units are also only for the convenience of distinguishing from each other, and are not used to limit the protection scope of the present invention.

Various other modifications and changes may be made by those skilled in the art based on the above-described technical solutions and concepts, and all such modifications and changes are intended to fall within the scope of the claims.

Claims

1. A battery protection circuit, comprising:

2. The battery protection circuit of claim 1, further comprising:

3. The battery protection circuit of claim 1, further comprising:

4. The battery protection circuit of claim 1, wherein the first switch driving unit comprises:

and the first end of the first switch unit is connected with the first driving unit, the charging locking unit and the overcurrent protection unit, the second end and the third end of the first switch unit are respectively connected with the negative electrode of the battery and the discharging negative interface, and the first switch unit is configured to open a discharging path between the negative electrode of the battery and the discharging negative interface when receiving the no overcurrent signal or disconnect the discharging path between the negative electrode of the battery and the discharging negative interface when receiving the overcurrent signal output by the overcurrent protection unit or the first level or the locking signal output by the charging locking unit.

5. The battery protection circuit of claim 1, wherein the second switch driving unit comprises:

6. The battery protection circuit of claim 4, wherein the first driving unit comprises: the circuit comprises a first current limiting resistor, an RC filter circuit, a first pull-down resistor, a first triode, a first diode and a first pull-up resistor;

7. The battery protection circuit of claim 5, wherein the second driving unit comprises: the second current limiting resistor, the second diode, the second pull-down resistor, the second triode, the second pull-up resistor and the third diode;

8. The battery protection circuit of claim 1, wherein the charge locking unit comprises: the fourth diode, the third current-limiting resistor, the third pull-up resistor and the third triode;

9. The battery protection circuit of claim 1, wherein the overcurrent protection unlocking unit comprises: the optical coupler OC1, a fourth current-limiting resistor, a first voltage-dividing resistor and an energy-storage capacitor;

10. The battery protection circuit of claim 1, wherein the over-current protection unit comprises: a fifth current limiting resistor, a second voltage dividing resistor, a third pull-down resistor and a fourth triode;