Lithium battery safety protection circuit

Abstract

The utility model relates to a lithium battery safety protection circuit comprising an MCU power supply circuit, a single-chip microcomputer MCU, a BMS protection circuit and a charging management circuit. The MCU power supply circuit provides voltage required by the single-chip microcomputer MCU. The single-chip microcomputer MCU is used for controlling and executing program instructions and performing real-time control. The BMS protection circuit is used for monitoring battery parameters to realize circuit protection; and the charging management circuit boosts the input voltage to the required voltage through the DC-DC conversion circuit so as to charge the battery. According to the lithium battery safety protection circuit, a lithium battery protection chip scheme and a single-chip microcomputer scheme are combined, the lithium battery protection chip is used for monitoring the voltage and the current of the lithium battery, the protection function is achieved by controlling the on-off state of the MOS tube, and the single-chip microcomputer can achieve complex protection logic and additional functions by controlling the MOS tube. Double insurance is achieved, the response speed is high, and reliability is high.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, and in particular to a lithium battery safety protection circuit. Background Technology

[0002] Lithium-ion batteries (commonly referred to as lithium batteries) are a type of rechargeable battery that primarily functions by the movement of lithium ions between the positive and negative electrodes. Lithium-ion batteries offer advantages such as high voltage, long cycle life, rapid charging, and a wide operating temperature range. Due to their high energy density and long cycle life, lithium batteries are widely used in various electronic devices. However, lithium batteries pose safety hazards under abnormal conditions such as overcharging, over-discharging, and overcurrent, thus requiring the inclusion of protection circuits.

[0003] Currently, solutions based on lithium battery protection chips implement basic protection functions such as overcharge, over-discharge, and overcurrent protection through dedicated protection chips, but cannot implement complex additional functions (such as status display, communication, etc.). Alternatively, solutions based on microcontrollers can implement complex protection logic and additional functions (such as LED display, communication, etc.) by controlling MOSFETs with a microcontroller. However, using a microcontroller to implement protection programs may have vulnerabilities, leading to protection failure. Utility Model Content

[0004] Therefore, the technical problem to be solved by this utility model is to overcome the shortcomings of the existing technology for lithium batteries, which still have defects in setting up a lithium battery protection board to control the charging and discharging of the battery pack and protect against overcharging and over-discharging of the lithium battery pack when the power supply is working, and cannot achieve effective protection.

[0005] To address the aforementioned technical problems, this utility model provides a lithium battery safety protection circuit, comprising: an MCU power supply circuit, a microcontroller (MCU), a battery management system (BMS) protection circuit, and a charging management circuit. The output terminal of the MCU power supply circuit is connected to the power input terminal of the MCU, and the MCU power supply circuit converts the input high voltage into the voltage required by the MCU to power it. The MCU communicates with the charging management circuit and is used for controlling and executing program instructions and for real-time control. The BMS protection circuit monitors battery parameters to achieve circuit protection. The charging management circuit uses a DC-DC converter circuit to boost the input voltage to the required voltage to charge the battery.

[0006] In one embodiment of this utility model, the MCU power supply circuit includes a sixth resistor, a second MOSFET, a seventh resistor, a ninth resistor, a tenth resistor, a first diode, a third diode, a fourth diode, a fifth diode, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a third MOSFET, a seventh capacitor, an eighth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, and a voltage regulator chip.

[0007] In one embodiment of this utility model, the microcontroller MCU is model BY32F002BF15P7.

[0008] In one embodiment of this utility model, the BMS protection circuit includes a 20th resistor, a 23rd resistor, a 25th resistor, a 28th resistor, a first switching resistor, a second switching resistor, a 16th capacitor, a 17th capacitor, an 18th capacitor, a 19th capacitor, a battery protection chip, a first fuse, a fourth MOSFET, a fifth MOSFET, a sixth MOSFET, a seventh MOSFET, an eighth MOSFET, a 15th capacitor, a 14th capacitor, a seventh diode, an 18th resistor, a 19th resistor, a 21st resistor, a 51st resistor, a 38th resistor, a 24th resistor, a 50th resistor, a 22nd resistor, a 27th resistor, a 29th resistor, a 30th resistor, a 22nd capacitor, a 23rd capacitor, a 29th capacitor, and a 31st capacitor.

[0009] In one embodiment of this utility model, the charging management circuit includes a fifth resistor, a second resistor, a first capacitor, a second capacitor, a first resistor, a sixth capacitor, a sixteenth MOSFET, a fifty-third resistor, a fifty-fifth resistor, a fifty-seventh resistor, a fifty-ninth resistor, a fifteenth transistor, a charging management chip, a first inductor, a fourth resistor, a first MOSFET, a second diode, a third capacitor, a fifth capacitor, a twenty-fifth capacitor, a ninth capacitor, a third resistor, and an eighth resistor.

[0010] In one embodiment of this utility model, the voltage regulator chip is model 78L05.

[0011] In one embodiment of this utility model, the battery protection chip is model JW3313.

[0012] In one embodiment of this utility model, the charging management chip is model CN3300.

[0013] In one embodiment of this utility model, the MCU power supply circuit further includes a first switch.

[0014] In one embodiment of this utility model, the MCU power supply circuit further includes a second switch.

[0015] Compared with the prior art, the above-mentioned technical solution of this utility model has the following beneficial effects:

[0016] The lithium battery safety protection circuit described in this utility model combines a lithium battery protection chip solution and a microcontroller solution. It includes a lithium battery, a lithium battery protection chip, a MOSFET, a microcontroller, buttons, and some resistors and capacitors. The lithium battery protection chip is used to monitor the voltage and current of the lithium battery and realizes the protection function by controlling the switching state of the MOSFET. The microcontroller can realize complex protection logic and additional functions (such as LED display, communication, etc.) by controlling the MOSFET. It achieves double protection, fast response speed, high reliability, and avoids protection failure caused by program bugs. Attached Figure Description

[0017] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0018] Figure 1 This is a circuit diagram of the MCU power supply circuit in a preferred embodiment of the present invention;

[0019] Figure 2 This is a circuit diagram of the microcontroller (MCU) in a preferred embodiment of this utility model;

[0020] Figure 3 This is a circuit diagram of the BMS protection circuit in a preferred embodiment of the present invention;

[0021] Figure 4 This is a circuit diagram of the charging management circuit in a preferred embodiment of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.

[0023] Reference Figure 1-4As shown, the lithium battery safety protection circuit of this utility model includes: an MCU power supply circuit 100, a single-chip microcomputer MCU 200, a BMS protection circuit 300, and a charging management circuit 400; the output terminal of the MCU power supply circuit 100 is connected to the power input terminal of the single-chip microcomputer MCU 200, and the MCU power supply circuit 100 converts the input high voltage into the voltage required by the single-chip microcomputer MCU 200 to power the single-chip microcomputer MCU 200; the single-chip microcomputer MCU 200 communicates with the charging management circuit 400, and the single-chip microcomputer MCU 200 is used to control and execute program instructions and perform real-time control; the BMS protection circuit 300 is used to monitor battery parameters to achieve circuit protection and prevent overcharging, over-discharging, overcurrent, etc.; the charging management circuit 400 uses a DC-DC converter circuit to increase the input voltage to the required voltage to charge the battery.

[0024] Reference Figure 1As shown, the MCU power supply circuit 100 includes a sixth resistor R6, a second MOSFET Q2, a seventh resistor R7, a ninth resistor R9, a tenth resistor R10, a first diode D1, a third diode D3, a fourth diode D4, a fifth diode D5, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a third MOSFET Q3, a seventh capacitor C7, an eighth capacitor C8, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, a thirteenth capacitor C13, a voltage regulator chip U2, a first switch S1, and a second switch S2. The first terminal of the eleventh resistor R11 is connected to the VDD_5V power supply, and the tenth... The second end of resistor R11 is divided into two branches. The first branch is connected in series with the fifth diode D5, and the second branch is connected in series with the thirteenth capacitor C13. The branch containing the fifth diode D5 is connected in series with the fourth diode D4 and the tenth resistor R10, and then connected to the gate of the second MOSFET Q2. The branch containing the thirteenth capacitor C13 is connected in series with the fourteenth resistor R14 and the twelfth resistor R12, and then serves as the power output terminal connected to the voltage input pin of the microcontroller MCU200. The line between the fourth diode D4 and the fifth diode D5, and the line between the thirteenth capacitor C13 and the fourteenth resistor R14, are connected to the first switch S1 and the second switch S2. With S2 in parallel, the gate of the third MOSFET Q3 is connected to the twelfth resistor R12. The source of the third MOSFET Q3 is connected to the line between the thirteenth capacitor C13 and the fourteenth resistor R14. The drain of the third MOSFET Q3 is connected to the line between the fourth diode D4 and the tenth resistor R10. The two ends of the sixth resistor R6 are connected to the source and the gate of the second MOSFET Q2, respectively. The drain of the second MOSFET Q2 is connected in series with the third diode D3 and then connected to the input pin of the voltage regulator chip U2. A branch of the line containing the third diode D3 is connected to the first diode D1. A voltage is generated between the drain of the second MOSFET Q2 and the third diode D3. A branch connects to the seventh resistor R7, which is connected in series with the ninth resistor R9 and then grounded. The twelfth capacitor C12 is connected in parallel with the ninth resistor R9. The seventh capacitor C7 and the eighth capacitor C8 are connected in parallel. The first end of the parallel connection of the seventh capacitor C7 and the eighth capacitor C8 is connected to the input pin of the voltage regulator chip U2, and the second end of the parallel connection of the seventh capacitor C7 and the eighth capacitor C8 is grounded. The tenth capacitor C10 and the eleventh capacitor C11 are connected in parallel. The first end of the parallel connection of the tenth capacitor C10 and the eleventh capacitor C11 is connected to the output pin of the voltage regulator chip U2, and the second end of the parallel connection of the tenth capacitor C10 and the eleventh capacitor C11 is grounded. The GND pin of the voltage regulator chip U2 is grounded.

[0025] Specifically, the voltage regulator chip U2 is model number 78L05.

[0026] Reference Figure 2As shown, the model of the microcontroller MCU200 is BY32F002BF15P7.

[0027] Reference Figure 3As shown, the BMS protection circuit 300 includes the twentieth resistor R20, the twenty-third resistor R23, the twenty-fifth resistor R25, the twenty-eighth resistor R28, the first switching resistor RS1, the second switching resistor RS2, the sixteenth capacitor C16, the seventeenth capacitor C17, the eighteenth capacitor C18, the nineteenth capacitor C19, the battery protection chip U3, the first fuse F1, the fourth MOSFET Q4, the fifth MOSFET Q5, the sixth MOSFET Q6, the seventh MOSFET Q7, the eighth MOSFET Q8, the fifteenth capacitor C15, the fourteenth capacitor C14, the seventh diode D7, the eighteenth resistor R18, the nineteenth resistor R19, the twenty-first resistor R21, the fifty-first resistor R51, and the thirty-eighth resistor. Resistors R38, R24 (24th), R50 (50th), R22 (22nd), R27 (27th), R29 (29th), R30 (30th), C22 (22nd), C23 (23rd), C29 (29th), and C31 (31st) are connected in series with resistor R20 at the VDD pin of battery protection chip U3. The line between the VDD pin of battery protection chip U3 and resistor R20 is connected to capacitor C16 and then grounded. Resistor R20 is connected in series with resistor R23 at the VC3 pin of battery protection chip U3. Resistor R25 is connected in series with resistor R25 at the VC2 pin of battery protection chip U3. The VC1 pin is connected in series with the 28th resistor R28. The GND pin of the battery protection chip U3 is grounded. The 17th capacitor C17 is connected between the VC3 and VC2 pins of the battery protection chip U3. The 18th capacitor C18 is connected between the VC2 and VC1 pins of the battery protection chip U3. The 19th capacitor C19 is connected between the VC1 and GND pins of the battery protection chip U3. The end of the 20th resistor R20 furthest from the battery protection chip U3 is connected in series with the first fuse F1 and then connected to the source of the fourth MOSFET Q4. The 15th capacitor C15 is connected between the drain and source of the fourth MOSFET Q4. The source of MOSFET Q4 is connected in series with the nineteenth resistor R19, which intersects with the gate of the fourth MOSFET Q4. The nineteenth resistor R19, after intersecting with the gate of the fourth MOSFET Q4, is then connected in series with the first terminal of the twenty-first resistor R21. The second terminal of the twenty-first resistor R21 is connected to the eighth MOSFET Q8. The second terminal of the eighth MOSFET Q8 is connected in series with the fiftieth resistor R50 and is connected to the CO pin of the battery protection chip U3. The third terminal of the eighth MOSFET Q8 is grounded. The thirty-eighth resistor R38 and the twenty-fourth resistor R24 ​​are connected in parallel. The first terminal of this parallel connection is grounded, and the second terminal is connected to the TS pin of the battery protection chip U3.The DO pin of battery protection chip U3 is connected in series with the 30th resistor R30 and then to the first terminal of the 7th MOSFET Q7. The second terminal of the 7th MOSFET Q7 is grounded. The third terminal of the 7th MOSFET Q7 is connected to the first terminal of the parallel connection of the first switching resistor RS1 and the second switching resistor RS2. The second terminal of the parallel connection of the first switching resistor RS1 and the second switching resistor RS2 is grounded. The 29th capacitor C29 and the 31st capacitor C31 are connected in series between the second terminal and the third terminal of the 7th MOSFET Q7. The WM pin of battery protection chip U3 is connected in series with the 27th resistor R27 and then to ground. The CS pin of battery protection chip U3 is connected in series with the 22nd capacitor C22 and then to ground. The first terminal of the 23rd capacitor C23 is grounded, and the second terminal of the 23rd capacitor C23 is connected to the battery protection chip U3. The WM pin of battery protection chip U3 is connected to the CS pin of the battery protection chip U3, which is connected to one end of the parallel connection of the first switching resistor RS1 and the second switching resistor RS2. The source of the fourth MOSFET Q4 is connected to the first terminal of the seventh diode D7. The second terminal of the seventh diode D7 is connected to the drain of the fifth MOSFET Q5. The fourteenth capacitor C14 is connected between the source and drain of the fifth MOSFET Q5. The gate of the fifth MOSFET Q5 is connected in series with the fifty-first resistor R51 to the drain of the sixth MOSFET Q6. The source of the fifty-first resistor R51 is grounded. The gate of the fifty-first resistor R51 is connected in series with the twenty-second resistor R22. The first terminal of the eighteenth resistor R18 is connected to the gate of the fifth MOSFET Q5, and the second terminal of the eighteenth resistor R18 is connected to the source of the fifth MOSFET Q5.

[0028] Specifically, the battery protection chip U3 is model JW3313.

[0029] Reference Figure 4As shown, the charging management circuit 400 includes a fifth resistor R5, a second resistor R2, a first capacitor C1, a second capacitor C2, a first resistor R1, a sixth capacitor C6, a sixteenth MOSFET Q16, a fifty-third resistor R53, a fifty-fifth resistor R55, a fifty-seventh resistor R57, a fifty-ninth resistor R59, a fifteenth transistor Q15, a charging management chip U1, a first inductor L1, a fourth resistor R4, a first MOSFET Q1, a second diode D2, a third capacitor C3, a fifth capacitor C5, a twenty-fifth capacitor C25, a ninth capacitor C9, a third resistor R3, and an eighth resistor R8. The fifty-ninth resistor R59 is connected to the base of the fifteenth transistor Q15, and the emitter of the fifteenth transistor Q15... The collector of the fifteenth transistor Q15 is connected in series with resistors R57 and R53, and then connected to the source of the sixteenth MOSFET Q16. The gate of the sixteenth MOSFET Q16 is connected to the line between resistors R57 and R53. The drain of the sixteenth MOSFET Q16 is connected to the VIN pin of the charging management chip U1. The first end of resistor R55 is connected to the drain of the sixteenth MOSFET Q16, and the second end of resistor R55 is grounded. The VCC pin of the charging management chip U1 is connected in series with capacitor C6 and then grounded. The CSN pin of the charging management chip U1 is connected in series with resistors R1 and R2 and then connected to the AD_TYPEC signal. The circuit between the second resistor R2 and the AD_TYPEC signal terminal is connected to the first terminal of the fifth resistor R5. The second terminal of the fifth resistor R5 is grounded. The first capacitor C1 and the second capacitor C2 are connected in parallel. The first terminal of the parallel connection of the first capacitor C1 and the second capacitor C2 is connected to the circuit between the first resistor R1 and the second resistor R2. The second terminal of the parallel connection of the first capacitor C1 and the second capacitor C2 is grounded. The GND pin of the charging management chip U1 is grounded. The point where the CSN pin of the charging management chip U1 intersects with the first resistor R1 is connected to the first terminal of the first inductor L1. The second terminal of the first inductor L1 is connected in series with the first terminal of the second diode D2. The second terminal of the second diode D2 is connected to the third capacitor C3, the fifth capacitor C5, and the second... The first end of the 15-capacitor C25 connected in parallel is connected to the drain of the first MOSFET Q1. The gate of the first MOSFET Q1 is connected to the DRV pin of the charging management chip U1 after being connected in series with the fourth resistor R4. The source of the first MOSFET Q1 is connected to the line between the first inductor L1 and the second diode D2. The FB pin of the charging management chip U1 is connected in series with the third resistor R3. The ninth capacitor C9 and the eighth resistor R8 are connected in parallel. The first end of the parallel connection of the ninth capacitor C9 and the eighth resistor R8 is connected to the line between the FB pin of the charging management chip U1 and the third resistor R3. The second end of the parallel connection of the ninth capacitor C9 and the eighth resistor R8 is grounded.

[0030] Specifically, the charging management chip U1 is model CN3300.

[0031] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A safety protection circuit for a lithium battery, characterized by comprising: include: MCU power supply circuit, microcontroller (MCU), BMS protection circuit and charging management circuit; The output terminal of the MCU power supply circuit is connected to the power input terminal of the microcontroller MCU, and the MCU power supply circuit converts the higher input voltage into the voltage required by the microcontroller MCU to power the microcontroller MCU. The microcontroller (MCU) communicates with the charging management circuit, and the MCU is used to control and execute program instructions and perform real-time control. The BMS protection circuit is used to monitor battery parameters to achieve circuit protection. The charging management circuit uses a DC-DC converter to boost the input voltage to the required voltage in order to charge the battery.

2. The lithium battery safety protection circuit according to claim 1, wherein: The MCU power supply circuit includes a sixth resistor, a second MOSFET, a seventh resistor, a ninth resistor, a tenth resistor, a first diode, a third diode, a fourth diode, a fifth diode, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a third MOSFET, a seventh capacitor, an eighth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, and a voltage regulator chip.

3. The lithium battery safety protection circuit of claim 1, wherein: The microcontroller MCU is model BY32F002BF15P7.

4. The lithium battery safety protection circuit of claim 1, wherein: The BMS protection circuit includes the 20th resistor, the 23rd resistor, the 25th resistor, the 28th resistor, the first switching resistor, the second switching resistor, the 16th capacitor, the 17th capacitor, the 18th capacitor, the 19th capacitor, a battery protection chip, the first fuse, the fourth MOSFET, the fifth MOSFET, the sixth MOSFET, the seventh MOSFET, the eighth MOSFET, the 15th capacitor, the 14th capacitor, the 7th diode, the 18th resistor, the 19th resistor, the 21st resistor, the 51st resistor, the 38th resistor, the 24th resistor, the 50th resistor, the 22nd resistor, the 27th resistor, the 29th resistor, the 30th resistor, the 22nd capacitor, the 23rd capacitor, the 29th capacitor, and the 31st capacitor.

5. The lithium battery safety protection circuit of claim 1, wherein: The charging management circuit includes a fifth resistor, a second resistor, a first capacitor, a second capacitor, a first resistor, a sixth capacitor, a sixteenth MOSFET, a fifty-third resistor, a fifty-fifth resistor, a fifty-seventh resistor, a fifty-ninth resistor, a fifteenth transistor, a charging management chip, a first inductor, a fourth resistor, a first MOSFET, a second diode, a third capacitor, a fifth capacitor, a twenty-fifth capacitor, a ninth capacitor, a third resistor, and an eighth resistor.

6. The lithium battery safety protection circuit of claim 2, wherein: The voltage regulator chip is model 78L05.

7. The lithium battery safety protection circuit of claim 4, wherein: The battery protection chip is model JW3313.

8. The lithium battery safety protection circuit of claim 5, wherein: The charging management chip is model CN3300.

9. The lithium battery safety protection circuit of claim 2, wherein: The MCU power supply circuit also includes a first switch.

10. The lithium battery safety protection circuit of claim 9, wherein: The MCU power supply circuit also includes a second switch.

Images