WO2021258366A1 - Control circuit, battery management system and electrochemical device - Google Patents

Abstract

The present application provides a control circuit. The control circuit comprises a charging wake-up circuit, a switch module, and a micro-controller; the switch module is electrically connected to a cell unit and a power supply loop of an external port, and the switch module is used for controlling the turn-on or turn-off of the power supply loop; the cell unit is electrically connected to the external port by means of the micro-controller and the switch module, the micro-controller is electrically connected to the switch module by means of the charging wake-up circuit, and the micro-controller is also electrically connected to the switch module; and the charging wake-up circuit is used for converting a signal inputted from the external port into a drive signal to awake the micro-controller by means of the drive signal, so as to control the turn-on or turn-off of the switch module by means of a control signal of the micro-controller. The present application further provides a battery management system and an electrochemical device. The control circuit provided in the present application has a simple structure and low costs, and is stable and reliable in performance.

Description

Control circuit, battery management system and electrochemical device Technical field

This application relates to the field of battery technology, and in particular to a control circuit, a battery management system and an electrochemical device having the control circuit.

Background technique

With the gradual improvement of people's quality of life, lithium batteries are gradually moving into people's daily lives. Lithium battery is a kind of secondary battery, which can be used repeatedly in charge and discharge cycle. After the power of the lithium battery is used up, it needs to be charged before it can be used. To this end, we have added a battery management system to manage the charging and discharging of lithium batteries. When the power of the lithium battery is used up, in the process of charging the lithium battery, the battery management system needs to be awakened when the charger is connected to the lithium battery to perform charging management. In the prior art, in order to ensure that the battery management system manages the charging of the lithium battery in real time, the battery management system usually does not enter a sleep state. This will cause problems such as high self-consumption of the battery management system.

Summary of the invention

In view of the foregoing, it is necessary to provide a control circuit, a battery management system and an electrochemical device having the control circuit. The battery management system can be put into a sleep state in time to save power.

An embodiment of the present application provides a control circuit applied to an electrochemical device. The control circuit includes a charging wake-up circuit, a switch module, and a microcontroller; the switch module is used to electrically connect to the cell unit of the electrochemical device In the power supply circuit connected to the external port of the electrochemical device, and used to control the on or off of the power supply circuit; the microcontroller is electrically connected to the switch module, and the microcontroller is used to control the switch module On or off; the charging and wake-up circuit includes a first resistor and a photocoupler, one end of the first resistor is electrically connected to the switch module, and the other end of the first resistor is electrically connected to the photocoupler Connected, the photocoupler is also electrically connected with the switch module; and the charging wake-up circuit is used for electrically connecting with the external port and the microcontroller, and is used for converting the signal input from the external port into The driving signal is used to wake up the microcontroller to control the on or off of the switch module.

According to some embodiments of the present application, the charging wake-up circuit detects the voltage across the switch module after the external port is connected to the charger, and when the voltage is greater than a preset voltage, turns on the photoelectric The coupler generates a driving signal that triggers the microcontroller to wake up the microcontroller to control the switch module to conduct. By adopting this technical solution, the microcontroller can be awakened to control the switch module to be turned on in time after the charger is connected, and the battery management system in the dormant state can be awakened to manage the charge and discharge of the battery cell. The circuit structure is simple and the performance is stable. reliable.

According to some embodiments of the present application, the charging wake-up circuit further includes a diode, the anode of the diode is electrically connected to the first resistor, and the cathode of the diode is electrically connected to the photocoupler.

According to some embodiments of the present application, the switch module includes a first electronic switch and a second electronic switch, the first end of the first electronic switch is electrically connected to the discharge pin of the microcontroller, and the first electronic switch The second end of the switch is used to electrically connect the negative electrode of the cell unit, the third end of the first electronic switch is electrically connected to the third end of the second electronic switch, and the first end of the second electronic switch is The second end of the second electronic switch is electrically connected to the charging pin of the microcontroller, the second end of the second electronic switch is used to electrically connect to the negative electrode of the external port, and the third end of the second electronic switch is electrically connected to the first electronic switch. The third end of the switch.

According to some embodiments of the present application, the photocoupler includes a switch unit and a light-emitting unit, one end of the light-emitting unit is electrically connected to the cathode of the diode, and the other end of the light-emitting unit is used to connect to the external port. The negative electrode is electrically connected, the first end of the switch unit is used to receive the light emitted by the light-emitting unit, the second end of the switch unit is grounded, and the third end of the switch unit is electrically connected to the microcontroller.

According to some embodiments of the present application, the second terminal of the first electronic switch is also electrically connected to the anode of the diode through the first resistor, and the second terminal of the second electronic switch is also connected to the light emitting unit. The other end is electrically connected.

According to some embodiments of the present application, the control circuit further includes a second resistor and a power source, and the third terminal of the switch unit is also electrically connected to the power source through the second resistor.

According to some embodiments of the present application, the switch module further includes a third electronic switch and a third resistor, the first end of the third electronic switch is connected to the pre-discharge pin of the microcontroller, and the third electronic switch The second end of the switch is used to electrically connect with the negative electrode of the battery cell unit, and the third end of the third electronic switch is connected between the first electronic switch and the second electronic switch through the third resistor. between.

An embodiment of the present application provides a battery management system, which includes the control circuit described above.

According to some embodiments of the present application, the control circuit further includes a collection module, which is configured to be electrically connected between the battery cell unit and the microcontroller, and is used to collect the parameters of the battery cell unit.

An embodiment of the present application provides an electrochemical device, the electrochemical device includes a battery cell unit, and the control circuit as described above, and the control circuit is used to control the charge and discharge of the battery cell unit.

The control circuit provided by the embodiment of the present application and the battery management system and electrochemical device having the control circuit detect the voltage difference between the two ends of the switch module after the charger is connected through the charging wake-up circuit, and the voltage When the voltage is greater than the preset voltage, the photocoupler in the charging wake-up circuit is turned on. A drive signal that triggers the microcontroller is generated, so that the microcontroller wakes up the battery management system, and sends a control signal to turn on the switch module to form a charging and discharging loop to control the charging and discharging of the battery cell unit. Therefore, when the charger is connected to the battery cell unit, the battery management system is awakened for charging management, and the battery management system enters a sleep state after the charging is completed, so as to avoid power loss or secondary overcharging of the battery cell unit. The control circuit and the battery management system provided by the embodiments of the present application have simple circuits, low cost, and stable and reliable performance.

Description of the drawings

Fig. 1 is a block diagram of an electrochemical device according to a first preferred embodiment of the present application.

Fig. 2 is a block diagram of an electrochemical device according to a second preferred embodiment of the present application.

Fig. 3 is a circuit diagram of a first embodiment of a control circuit in the battery management system in Fig. 1.

Fig. 4 is a circuit diagram of a second embodiment of the control circuit in the battery management system in Fig. 1.

Symbol description of main components

Control circuit 100

Battery management system 200

Cell unit 300

External port 400

Charger 500

Electrochemical device 600

Charging wake-up circuit 10

Switch module 11

Microcontroller 12

Collection module 13

Power supply 14

Pre-discharge switch module 15

First resistor R1

Second resistance R2

The third resistor R3

Fourth resistor R4

Diode D1

The first electronic switch K1

The second electronic switch K2

The third electronic switch K3

Optocoupler U1

Switch unit 16

Light-emitting unit 17

The following specific embodiments will further illustrate this application in conjunction with the above-mentioned drawings.

detailed description

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is a part of the embodiments of the present invention, not all the embodiments.

In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly defined and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. ; It can be a mechanical connection, an electrical connection or a mutual communication; it can be a direct connection or an indirect connection through an intermediate connection, and it can be the internal communication between two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be immediately based on specific circumstances.

The terms "first", "second" and "third" in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific sequence. In addition, the term "including" and any variations of them are intended to cover non-exclusive inclusion.

Based on the implementation manners in this application, all other implementation manners obtained by those of ordinary skill in the art without creative work fall within the protection scope of this application.

Please refer to FIG. 1. FIG. 1 is a block diagram of a preferred embodiment of an electrochemical device according to the present application. The electrochemical device 600 includes a cell unit 300 and a control circuit 100 electrically connected to the cell unit 300. The control circuit 100 is located in the battery management system 200 and is used to control the battery management system 200 to perform charge and discharge management of the battery cell unit 300. The control circuit 100 is electrically connected between the battery cell unit 300 and the external port 400 to form a power supply loop. The control circuit 100 is used to control the power supply loop to be turned on or off, thereby controlling the battery management system 200 The charge and discharge management of the battery cell unit 300 is performed.

The control circuit 100 includes a charging wake-up circuit 10, a switch module 11 and a microcontroller 12.

Specifically, in the embodiment of the present application, the switch module 11 is located in the power supply circuit between the negative electrode of the battery cell unit 300 and the external port 400, and the microcontroller 12 is connected to the battery cell unit 300 and the charging wake-up Between circuit 10. The charging wake-up circuit 10 is connected between the microcontroller 12 and the switch module 11. The microcontroller 12 is also electrically connected to the switch module 11. The charging wake-up circuit 10 is used to convert a signal input from the external port 400 into a drive signal, wake up the microcontroller 12 through the drive signal, and drive the microcontroller 12 through the control signal of the microcontroller 12 The switch module 11 is turned on or off.

In an embodiment, the control circuit 100 further includes an acquisition module 13, as shown in FIG. 2. The acquisition module 13 is electrically connected between the battery cell unit 300 and the microcontroller 12. The acquisition module 13 is used for sampling the parameters (such as voltage, current, etc.) of the battery cell unit 300.

In one embodiment, the control circuit 100 further includes a power source 14, and the power source 14 is connected to the microcontroller 12 through the charging wake-up circuit 10. The power supply 14 is used to provide electric energy Vcc to the microcontroller 12, for example, Vcc is 3.3V.

In one embodiment, the positive electrode of the external port 400 can be electrically connected to the positive electrode of a charger 500, and the negative electrode of the external port 400 can be electrically connected to the negative electrode of the charger 500.

Please refer to FIG. 3, which is a circuit diagram of the first embodiment of the control circuit 100 according to the present application.

In this embodiment, the switch module 11 includes a first electronic switch K1 and a second electronic switch K2. The first end of the first electronic switch K1 is connected to the discharge pin DSG of the microcontroller 12, the second end of the first electronic switch K1 is connected to the negative electrode of the cell unit 300, and the first electronic The third end of the switch K1 is connected to one end of the second electronic switch K2. The first end of the second electronic switch K2 is connected to the charging pin CHG of the microcontroller 12, the second end of the second electronic switch K2 is connected to the negative electrode of the external port 400, and the second electronic switch The third terminal of K2 is connected to the third terminal of the first electronic switch K2.

In this embodiment, the first electronic switch K1 and the second electronic switch K2 are both N-type field effect transistors. The first end, the second end, and the third end of the first electronic switch K1 and the second electronic switch K2 correspond to the gate, source, and drain of the N-type field effect transistor, respectively.

In this embodiment, the charging wake-up circuit 10 includes a first resistor R1, a diode D1, and a photocoupler U1.

The first resistor R1 is connected in series in the power supply loop as a current limiting resistor. Wherein, one end of the first resistor R1 is electrically connected to the second end of the first electronic switch K1, the other end of the first resistor R1 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to The photocoupler U1 is connected.

In this embodiment, the first end of the photocoupler U1 is connected to the cathode of the diode D1, and the second end of the photocoupler U1 is connected to the second end of the second electronic switch K2, so The third end of the photocoupler is grounded, and the fourth end of the photocoupler is connected to the microcontroller 12. The fourth terminal of the photocoupler U1 is also connected to the power source 14 through a second resistor R2. The second resistor R2 is a pull-up resistor.

Specifically, the photocoupler U1 includes a switch unit 16 and a light-emitting unit 17. The switch unit 16 may be a photosensitive triode, and the light-emitting unit 17 may be a light-emitting diode. One end of the light emitting unit 17 is connected to the cathode of the diode D1, and the other end of the light emitting unit 17 is connected to the cathode of the external port 400. The first end of the switch unit 16 is used to receive the light emitted by the light emitting unit 17, the second end of the switch unit 16 is grounded, and the third end of the switch unit 16 is connected to the microcontroller 12. The third terminal of the switch unit 16 is also connected to the power source 14 through the second resistor R2. The first end, the second end and the third end of the switch unit 16 respectively correspond to the base, emitter and collector of the photosensitive transistor. The first end of the photocoupler U1 corresponds to one end of the light emitting unit 17, the second end of the photocoupler U1 corresponds to the other end of the light emitting unit 17, and the third end of the photocoupler U1 corresponds to The second terminal of the switch unit 16 and the fourth terminal of the photocoupler U1 correspond to the third terminal of the switch unit 16.

In this embodiment, the second end of the first electronic switch K1 is also connected to the charging wake-up circuit 10. Specifically, the second terminal of the first electronic switch K1 is connected to the anode of the diode D1 through the first resistor R1. The second end of the second electronic switch K2 is connected to the second end of the photocoupler U1.

In this embodiment, the diode D1 is a unidirectional diode, which is used to prevent the reverse direction voltage and avoid damage caused by the reverse voltage at both ends of the photocoupler U1 exceeding 6V. The diode D1 is a BAV21 with a directional withstand voltage of 250V, and a forward conduction voltage of 0.7V. The photocoupler U1 is used to detect the voltage across the switch module 11. When the charger 500 is connected, the voltage difference between the cell unit 300 and the charger 500 can cause the photocoupler U1 to conduct, thereby generating a driving signal that triggers the microcontroller 12 (Such as a low-level signal) to generate a control signal through the microcontroller 12 to control the switch module 11 to turn on, and activate the battery management system 200 to perform charge and discharge management of the battery cell unit 300. In an embodiment, the photocoupler U1 may be a general low-speed photocoupler, such as LTV-217, with a forward conduction voltage of 1.2V.

In this embodiment, when the load is an inductive load, the terminal voltage of the negative electrode of the external port 400 is at most twice the terminal voltage of the positive electrode of the external port 400 when the switch module 11 is turned off. At this time, the voltage at both ends of the charging and wake-up circuit 10 is the maximum voltage of the reversed cell unit 300, and the diode D1 can prevent the reverse voltage from damaging the components.

In this embodiment, the first resistor R1 is used to limit the operating current of the charging and wake-up circuit 10 to ensure that the photocoupler U1 is normally driven.

In one embodiment, the first resistor R1 is used as a current limiting resistor in series in the circuit, and the resistance value of R1 determines the operating current of the circuit. The magnitude of the working current is equal to the voltage U _{10 across the switch module 11 minus the voltage U 20} across the first resistor R1, minus the conduction voltage U _{30 of the} diode D1, and minus the conduction of the photocoupler U1 After the voltage U _{40 is} divided by the resistance value of the first resistor R1, that is, the working current=(U ₁₀ -U ₂₀ -U ₃₀ -U ₄₀ )/R1.

When the switch module 11 is turned on, it can be obtained that the circuit turn-on voltage is 1.2V+0.7V+1mA×R1=2.2V. When the voltage difference between the charger 500 and the cell unit 300 is less than the circuit conduction voltage (such as 2.2V), the battery management system 200 will not be activated. That is, after the battery cell unit 300 is fully charged, the battery management system 200 is not allowed to be activated, so as to avoid recharging the battery cell unit 300 after it is fully charged, which will cause the life of the battery cell unit 300 to decrease and the battery cell unit 300 to be fully charged. Status of lithium analysis risk. When the battery cell unit 300 does not reach a fully charged state, the voltage of the battery cell unit 300 will be lower than the voltage of the charger 500. When the voltage difference between the charger 500 and the cell unit 300 reaches the circuit conduction voltage, the battery management system 200 is activated to manage the charge and discharge of the cell unit 300.

It should be noted that the maximum voltage difference between the charger 500 and the cell unit 300 is equal to the output voltage of the charger minus the discharge protection voltage of the cell unit 300. For example, when the charger output voltage is 83V and the discharge protection voltage of the cell unit 300 is 60V, the maximum voltage difference is 23V. Therefore, the maximum operating current=(23V-1.2V-0.7V)/R1=42mA can be obtained. The maximum working current of the photoelectric coupler U1 can reach 50 mA, which can meet this extreme working requirement.

The charging wake-up circuit 10 is used to convert the signal input from the external port 400 into a drive signal, wake up the microcontroller 12 through the drive signal, and control the microcontroller 12 through the control signal of the microcontroller 12 The switch module 11 is turned on or off. Specifically, when the cell unit 300 enters the sleep state, the first electronic switch K1 and the second electronic switch K2 are in an off state. The charging wake-up circuit 10 detects the voltage across the switch module 11 after the external port 400 is connected to the charger 500, and turns on the photocoupler U1 when the voltage is greater than a preset voltage. Generate a driving signal to trigger the microcontroller 12 (such as a falling edge interrupt trigger signal from 3.3V to 0V), so that the microcontroller 12 wakes up the battery management system 200 and sends a control signal to turn on the switch The module 11 forms a charging and discharging circuit to control the charging and discharging of the battery cell unit 300.

Please refer to FIG. 4, which is a circuit diagram of a second embodiment of the control circuit 100 of the present application.

The difference between the control circuit 100 of this embodiment and the control circuit 100 of the first embodiment is:

In this embodiment, the switch module 11 further includes a pre-discharge switch module 15, and the pre-discharge switch module 15 includes a third electronic switch K3 and a third resistor R3.

One end of the third electronic switch K3 is connected to the negative electrode of the cell unit 300, and the other end of the third electronic switch K3 is connected to the first switch K1 and the second switch K1 through the third resistor R3. Switch between K2.

Specifically, the first end of the third electronic switch K3 is connected to the pre-discharge pin PDSG of the microcontroller 12, and the second end of the third electronic switch K3 is connected to the negative electrode of the cell unit 300, The third terminal of the third electronic switch K3 is connected between the first switch K1 and the second switch K2 through the third resistor R3.

In this embodiment, the second end of the third electronic switch K3 is also connected to the charging wake-up circuit 10. Specifically, the second terminal of the third electronic switch K3 is connected to the anode of the diode D1 through the first resistor R1.

In this embodiment, the third electronic switch K3 is an N-type field effect transistor. The first terminal, the second terminal, and the third terminal of the third electronic switch K3 correspond to the gate, source, and drain of the N-type field effect transistor, respectively.

In one embodiment, the control circuit 100 further includes a fourth resistor R4, and the fourth resistor R4 is a sampling resistor for detecting the charging current of the control circuit 100. One end of the fourth resistor R4 is used to electrically connect the negative electrode of the cell unit 300, and the other end of the fourth resistor R4 is electrically connected to the second end of the first electronic switch K1 and the third electronic switch K3 .

It should be noted that the control circuit 100 of the first embodiment of the present application may also include the fourth resistor R4 (as shown in FIG. 3), and the fourth resistor R4 is a sampling resistor for detecting the control circuit 100 The charging current. One end of the fourth resistor R4 is used to electrically connect the negative electrode of the cell unit 300, and the other end of the fourth resistor R4 is electrically connected to the second end of the first electronic switch K1.

In one embodiment, the circuit diagram of the first embodiment of the control circuit 100 of the present application is taken as an example for description:

When in use, the control circuit 100 does not include the pre-discharge switch module 15, and the cell unit 300 is in a standby state, that is, a non-charging state. In order to avoid power loss, the cell unit 300 enters a sleep state, the first electronic switch K1 and the second electronic switch K2 are both in an off state, and the battery management system 200 is in a sleep state. When the charger is connected through the external port 400, a pressure difference is generated between the battery cell unit 300 and the charger 500, and when the first electronic switch K1 and the second electronic switch K2 are detected When the voltage at the terminal is greater than a preset voltage (such as 2.2V), the switch unit 16 in the photocoupler U1 is triggered to turn on, and a driving signal that triggers the microcontroller 12 (such as a falling edge interrupt from 3.3V to 0V) is generated. Trigger signal) to make the microcontroller 12 wake up the battery management system and send a control signal to turn on the first electronic switch K1 and the second electronic switch K2 to form a charging and discharging circuit to control the battery cell unit 300 Charge and discharge.

In another embodiment, the circuit diagram of the second embodiment of the control circuit 100 of the present application is taken as an example for description:

Since it is necessary to continuously supply power to the loads of the control circuit 100 (such as meters and lights of an electric vehicle) through pre-discharge, the pre-discharge switch module 15 needs to maintain a constant power output. That is, when the first electronic switch K1 and the second electronic switch K2 are in the off state, the third electronic switch K3 is in the on state. When the battery management system 200 is awakened by connecting a charger through the external port 400, the second electronic switch K2 is in a conducting state. Because there is a diode inside the second electronic switch K2, and the discharge direction is turned on. Therefore, the normal output voltage can be obtained in the battery cell unit 300. When the first electronic switch K1 is also in the on state, due to the existence of the pre-discharge switch module 15, the cell unit 300 can still obtain an output voltage.

However, when the output voltage range of the battery cell unit 300 is 81.2V-83V, in the case that both the battery cell unit 300 and the connected charger 500 can activate the control circuit 100, it is not certain that the control circuit 100 can be activated. Whether the driving signal comes from the battery cell unit 300 or the charger 500. Therefore, the battery management system 200 does not enter a sleep state, and needs to determine whether the battery cell unit 300 is charging by detecting the current of the power supply loop.

When the voltage of the battery cell unit 300 is less than 81.2V, the battery cell unit 300 cannot enable the control circuit 100, the battery cell unit 300 can enter a low-power sleep state, and the battery management system 200 also Enter the sleep state; when the charger 500 is connected through the external port 400, the control circuit 100 is enabled, and the microcontroller 12 is triggered to wake up the battery management system 200, so that the battery cell unit 300 enters the normal charging state.

In the control circuit 100 and the battery management system 200 provided with the control circuit 100 in the above-mentioned embodiment, the charging wake-up circuit 10 detects the voltage across the switch module 11 after the charger 500 is connected, and the voltage When the voltage is greater than the preset voltage, the photocoupler U1 in the charging wake-up circuit 10 is turned on. A drive signal (such as a low-level signal) that triggers the microcontroller 12 is generated, so that the microcontroller 12 wakes up the battery management system and sends a control signal to turn on the first electronic switch K1 and the second electronic switch. The switch K2 forms a charging and discharging circuit to control the charging and discharging of the battery cell unit 300. In this way, the control circuit 100 and the battery management system 200 provided by the embodiments of the present application can wake up the battery management system 200 for charging management when the charger 500 is connected to the battery cell unit 300, and put the battery management system 200 to sleep after the charging ends. In order to avoid power loss or secondary overcharging of the battery cell 300, the control circuit 100 has the characteristics of simple circuit, low cost, stable and reliable performance.

Those of ordinary skill in the art should realize that the above embodiments are only used to illustrate the application, and not as a limitation to the application, as long as they are within the essential spirit of the application, the above embodiments are appropriately made. Changes and changes fall within the scope of protection claimed by this application.

Claims (11)

A control circuit applied to an electrochemical device, characterized in that the control circuit includes a charging wake-up circuit, a switch module, and a microcontroller; The switch module is used to electrically connect the cell unit of the electrochemical device and the power supply circuit of the external port of the electrochemical device, and is used to control the on or off of the power supply circuit; The microcontroller is electrically connected to the switch module, and the microcontroller is used to control the on or off of the switch module; The charging wake-up circuit includes a first resistor and a photocoupler. One end of the first resistor is electrically connected to the switch module, and the other end of the first resistor is electrically connected to the photocoupler. The device is also electrically connected with the switch module; and The charging wake-up circuit is used to electrically connect with the external port and the microcontroller, and is used to convert the signal input from the external port into a drive signal to wake up the microcontroller to control the conduction of the switch module. On or off. The control circuit of claim 1, wherein the charging wake-up circuit detects the voltage across the switch module after the external port is connected to the charger, and when the voltage is greater than a preset voltage , Turning on the photocoupler to generate a driving signal that triggers the microcontroller to wake up the microcontroller to control the switching module to conduct. The control circuit according to claim 1, wherein the charging and wake-up circuit further comprises a diode, the anode of the diode is electrically connected to the first resistor, and the cathode of the diode is electrically connected to the photocoupler . The control circuit of claim 3, wherein the switch module comprises a first electronic switch and a second electronic switch, and the first end of the first electronic switch is electrically connected to the discharge pin of the microcontroller , The second terminal of the first electronic switch is used to electrically connect the negative electrode of the cell unit, the third terminal of the first electronic switch is electrically connected to the third terminal of the second electronic switch, and the second The first terminal of the electronic switch is electrically connected to the charging pin of the microcontroller, the second terminal of the second electronic switch is used to electrically connect the negative electrode of the external port, and the third terminal of the second electronic switch is electrically connected Connect the third terminal of the first electronic switch. The control circuit according to claim 4, wherein the photocoupler comprises a switch unit and a light-emitting unit, one end of the light-emitting unit is electrically connected to the cathode of the diode, and the other end of the light-emitting unit is used for It is electrically connected to the negative electrode of the external port, the first end of the switch unit is used to receive the light emitted by the light-emitting unit, the second end of the switch unit is grounded, and the third end of the switch unit is connected to the The microcontroller is electrically connected. The control circuit of claim 5, wherein the second terminal of the first electronic switch is also electrically connected to the anode of the diode through the first resistor, and the second terminal of the second electronic switch is electrically connected to the anode of the diode through the first resistor. It is also electrically connected to the other end of the light-emitting unit. 7. The control circuit of claim 6, wherein the control circuit further comprises a second resistor and a power source, and the third terminal of the switch unit is also electrically connected to the power source through the second resistor. The control circuit according to claim 7, wherein the switch module further comprises a third electronic switch and a third resistor, and the first end of the third electronic switch is connected to the pre-discharge pin of the microcontroller , The second terminal of the third electronic switch is used to electrically connect with the negative electrode of the battery cell unit, and the third terminal of the third electronic switch is connected to the first electronic switch and the electrical outlet through the third resistor. Between the second electronic switch. A battery management system, wherein the battery management system comprises the control circuit according to any one of claims 1 to 8. The battery management system according to claim 9, wherein the control circuit further comprises a collection module, and the collection module is configured to be electrically connected between the battery cell unit and the microcontroller, and is used to collect the battery cell. The parameters of the unit. An electrochemical device, the electrochemical device comprising a battery cell, characterized in that the electrochemical device further comprises the control circuit according to any one of claims 1 to 8, the control circuit is used to control the The charging and discharging of the battery cell unit.

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