A lithium battery charge / discharge protection circuit with shutdown protection

Abstract

This utility model relates to the field of lithium power supply unit protection technology, and more particularly to a lithium battery charge and discharge protection circuit with shutdown protection, comprising: a charging protection module, an overcharge and over-discharge protection module, an overcurrent detection module, and a power supply module. Specifically, the overcurrent detection module is electrically connected to MOSFETs Q6.1 and Q6.2, with the drain (D) of MOSFET Q6.1 and the source (S) of MOSFET Q6.2 electrically connected. A capacitor C6, a capacitor C7, a resistor RS4, and a Zener diode U2 are electrically connected between MOSFETs Q6.1 and Q6.2. This utility model uses the charging protection module to perform overall circuit detection and control, preventing the influence of factors such as temperature and voltage on the overall circuit. The overcharge and over-discharge protection module further protects the circuit's safety, and the overcurrent detection module allows for real-time data detection of the entire circuit, enabling rapid processing, analysis, and control.

Description

Technical Field

[0001] This utility model relates to the field of lithium power supply unit protection technology, and in particular to a lithium battery charge and discharge protection circuit with shutdown protection. Background Technology

[0002] With the widespread application of electric equipment, lithium-ion power supply units have become a major energy source due to their advantages such as high energy density and long cycle life. However, during the frequent start-stop processes of motors, lithium-ion power supply units need to withstand large instantaneous current surges, which poses a severe challenge to the lifespan and safety of the power supply units.

[0003] Existing lithium power supply unit protection circuits are mostly designed for conventional charging and discharging scenarios, lacking effective protection against instantaneous current surges during motor start-up and shutdown. This can easily lead to cell damage and affect the stable operation of the equipment. Therefore, developing a lithium power supply unit charging and discharging protection circuit that can effectively cope with instantaneous current surges during motor start-up and shutdown is of great practical significance. Utility Model Content

[0004] This utility model addresses the shortcomings of existing technologies by providing the following technical solution:

[0005] A lithium battery charge and discharge protection circuit with shutdown protection includes: a charging protection module, an overcharge and over-discharge protection module, an overcurrent detection module, and a power supply module;

[0006] The charging protection module includes a chip U1, and the overcharge and over-discharge protection module, the overcurrent detection module, and the power module are all electrically connected to the chip U1.

[0007] Specifically, the overcurrent detection module is electrically connected to MOSFETs Q6.1 and Q6.2. The drain (D) of MOSFET Q6.1 is electrically connected to the source (S) of MOSFET Q6.2. A capacitor C6, a capacitor C7, a resistor RS4, and a Zener diode U2 are electrically connected between MOSFETs Q6.1 and Q6.2. The other end of capacitor C7 is electrically connected to the source (S) of MOSFET Q7. The other end of resistor RS4 is electrically connected to resistor RS3. Resistor RS4 is connected in parallel with Zener diode U2. The other end of resistor RS3 is electrically connected to the source (S) of MOSFET Q8. A resistor RS2 is electrically connected to the gate (G) of MOSFET Q8. Resistor RS2, MOSFET Q7, and MOSFET Q6.1 are connected in parallel.

[0008] The resistor RS2, the drain of the MOSFET Q8, the resistor RCO1, the gate and drain of the MOSFET Q7, the resistor RS1, and the source of the MOSFET Q6.1 are all connected to the main power circuit of the power module through the diode DIN1.

[0009] As an improvement to the above technical solution, the overcharge and over-discharge protection module includes resistors R7 and R8. Resistor R7 is electrically connected to pin 2 of chip U1, and resistor R8 is electrically connected to pin 3 of chip U1. The other ends of resistors R7 and R8 are both electrically connected to the power module through resistor RVCC1.

[0010] As an improvement to the above technical solution, the overcurrent detection module includes capacitors COV1, COVD1, COVC1, COVC2, resistors RNTC1, RTRH1, RVM1, diode D7, resistors RDO1, RCO1, RS1, RVIN1, and capacitor CVIN1.

[0011] Specifically, pin 4 of chip U1 is electrically connected to capacitor COV1 and then grounded; pin 5 of chip U1 is electrically connected to capacitor COVD1 and then grounded; pin 6 of chip U1 is electrically connected to capacitor COVC1 and then grounded; pin 7 of chip U1 is electrically connected to capacitor COVC2 and then grounded; pin 8 of chip U1 is electrically connected to resistor RNTC1 and then grounded; pin 9 of chip U1 is electrically connected to resistor RTRH1 and then grounded; pin 10 of chip U1 is electrically connected to resistor RVM1 and then electrically connected to the power module; pin 11 of chip U1 is electrically connected to diode D7; and the pins of chip U1... 12 is electrically connected to the resistor RDO1. The other end of the diode D7 is electrically connected to the resistor RCO1, the resistor RS1, the gate of the MOSFET Q6.1, and the resistor RDO1. The other end of the resistor RDO1 is electrically connected to the gate of the MOSFET Q6.2. The other end of the resistor RCO1 is electrically connected to the gate of the MOSFET Q7. The other end of the resistor RS1 is electrically connected between the drain of the MOSFET Q7 and the source of the MOSFET Q6.1. Pin 14 of the chip U1 is electrically connected to the resistor RVIN1 and the capacitor CVIN1. There is a resistor Rsense1 between the resistor RVIN1 and the capacitor CVIN1.

[0012] As an improvement to the above technical solution, the power module is composed of several power supply units connected in series;

[0013] Specifically, the positive terminal of one of the power supply units BT1 is electrically connected to pin 19 of the chip U1. A resistor RD1 is electrically connected between the power supply unit BT1 and pin 19 of the chip U1. The other end of the resistor RD1 is electrically connected to the drain (D) terminal of the MOSFET Q1. The gate (G) terminal of the MOSFET Q1 is electrically connected to pin 18 of the chip U1 through a resistor RG1. Pin 17 of the chip U1 is electrically connected to the resistor RG1 through a capacitor C1. Pin 17 of the chip U1 is electrically connected to the source (S) terminal of the MOSFET Q1 and then grounded.

[0014] As an improvement to the above technical solution, pin 28 of the chip U1 is electrically connected between resistor R7 and capacitor RVCC1.

[0015] The beneficial effects of this utility model are:

[0016] The charging protection module performs overall circuit detection and control to prevent factors such as temperature and voltage from affecting the overall circuit. In conjunction with the overcharge and over-discharge protection module, the circuit safety is further protected. With the overcurrent detection module, the overall circuit data can be detected in real time to achieve rapid processing, analysis and control. Attached Figure Description

[0017] Figure 1 This is the overall circuit diagram of this utility model;

[0018] Figure 2 This is a partial circuit diagram of the left half of this utility model;

[0019] Figure 3 This is the right half of the circuit diagram in this utility model. Detailed Implementation

[0020] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0021] Existing lithium power supply unit protection circuits are mostly designed for conventional charging and discharging scenarios, lacking effective protection against instantaneous current surges during motor start-up and shutdown. This can easily lead to cell damage and affect the stable operation of the equipment. Therefore, developing a lithium power supply unit charging and discharging protection circuit that can effectively cope with instantaneous current surges during motor start-up and shutdown is of great practical significance.

[0022] To resolve this issue, please refer to [link / reference]. Figure 1-3A lithium battery charge and discharge protection circuit with shutdown protection includes: a charging protection module, an overcharge and over-discharge protection module, an overcurrent detection module, and a power supply module.

[0023] The charging protection module includes chip U1, an overcharge and over-discharge protection module, an overcurrent detection module, and a power supply module, all of which are electrically connected to chip U1.

[0024] Specifically, the overcurrent detection module is electrically connected to MOSFETs Q6.1 and Q6.2. The drain (D) of MOSFET Q6.1 is electrically connected to the source (S) of MOSFET Q6.2. MOSFETs Q6.1 and Q6.2 are electrically connected to capacitors C6 and C7, resistor RS4, and Zener diode U2. The other end of capacitor C7 is electrically connected to the source (S) of MOSFET Q7. The other end of resistor RS4 is electrically connected to resistor RS3. Resistor RS4 is connected in parallel with Zener diode U2. The other end of resistor RS3 is electrically connected to the source (S) of MOSFET Q8. The gate (G) of MOSFET Q8 is electrically connected to resistor RS2. Resistor RS2, MOSFET Q7, and MOSFET Q6.1 are connected in parallel.

[0025] Resistor RS2, the drain of MOSFET Q8, resistor RCO1, the gate and drain of MOSFET Q7, resistor RS1, and the source of MOSFET Q6.1 are all connected to the main power circuit of the power module through diode DIN1.

[0026] In this embodiment, when the battery is connected to the motor for start-up and stop, in addition to MOSFETs Q6.1 and Q6.2 being turned off, capacitor C6 connected in parallel to MOSFET Q6.1 also provides energy during startup and stores energy during shutdown to smooth voltage fluctuations. However, during the battery shutdown process, if a product such as a motor is connected, a reverse electromotive force may be generated by magnetization due to inertia or other reasons. At this time, the reverse electromotive force will cause the gate voltage of MOSFET Q7 to be greater than its turn-on voltage, turning on MOSFET Q7 and connecting capacitor C7 to the circuit, increasing the capacitance value across MOSFET Q6.1 and reducing voltage fluctuations.

[0027] Furthermore, the electromotive force will turn on the MOSFET Q8, and the energy will be dissipated in the resistors through resistors RS3 and RS4 and Zener diode U2, preventing interference to other parts of the battery pack.

[0028] In one embodiment, see Figure 1-3 The overcharge and over-discharge protection module includes resistors R7 and R8. Resistor R7 is electrically connected to pin 2 of chip U1, and resistor R8 is electrically connected to pin 3 of chip U1. The other ends of resistors R7 and R8 are both electrically connected to the power module through resistor RVCC1.

[0029] Pins 2 and 3 of chip U1 are used for discharge input signal and charging input signal respectively, mainly to work with the charging protection module for further protection.

[0030] In one embodiment, see Figure 1-3 The overcurrent detection module includes capacitors COV1, COVD1, COVC1, COVC2, resistors RNTC1, RTRH1, RVM1, diode D7, resistors RDO1, RCO1, RS1, RVIN1, and capacitor CVIN1.

[0031] Specifically, pin 4 of chip U1 is electrically connected to capacitor COV1 and then grounded; pin 5 of chip U1 is electrically connected to capacitor COVD1 and then grounded; pin 6 of chip U1 is electrically connected to capacitor COVC1 and then grounded; pin 7 of chip U1 is electrically connected to capacitor COVC2 and then grounded; pin 8 of chip U1 is electrically connected to resistor RNTC1 and then grounded; pin 9 of chip U1 is electrically connected to resistor RTRH1 and then grounded; pin 10 of chip U1 is electrically connected to resistor RVM1 and then electrically connected to the power module; pin 11 of chip U1 is electrically connected to diode D7; and pin 12 of chip U1 is electrically connected to... Resistor RDO1 is electrically connected. The other end of diode D7 is electrically connected to resistor RCO1, resistor RS1, the gate of MOSFET Q6.1, and resistor RDO1. The other end of resistor RDO1 is electrically connected to the gate of MOSFET Q6.2. The other end of resistor RCO1 is electrically connected to the gate of MOSFET Q7. The other end of resistor RS1 is electrically connected between the drain of MOSFET Q7 and the source of MOSFET Q6.1. Pin 14 of chip U1 is electrically connected to resistor RVIN1 and capacitor CVIN1. There is resistor Rsense1 between resistor RVIN1 and capacitor CVIN1.

[0032] During discharge, resistors RNTC1 and RTRH1 are connected to the corresponding pins and ground. The charging temperature Rtrh = 2 * Rntc = 50 degrees Celsius, and the discharging temperature NTC = 0.54 * Rntc = 60 degrees Celsius. This is used to detect the temperature of the battery cell during charging and discharging to prevent overheating and protect the battery cell.

[0033] In one embodiment, see Figure 1-3 The power module consists of several power supply units;

[0034] Specifically, the positive terminal of one of the power supply units BT1 is electrically connected to pin 19 of chip U1. A resistor RD1 is electrically connected between power supply unit BT1 and pin 19 of chip U1. The other end of resistor RD1 is electrically connected to the drain terminal of MOSFET Q1. The gate terminal of MOSFET Q1 is electrically connected to pin 18 of chip U1 through resistor RG1. Pin 17 of chip U1 is electrically connected to resistor R1 through capacitor C1. Pin 17 of chip U1 is electrically connected to the source terminal of MOSFET Q1 and then grounded.

[0035] During charging and discharging, the BM3451 collects the voltage of each cell and balances the voltage of each cell by turning on or off the corresponding Q1, Q2, Q3, Q4, Q5 MOS transistors and corresponding current-limiting resistors when charging or discharging.

[0036] In one embodiment, see Figure 1-3 Pin 28 of chip U1 is electrically connected between resistor R7 and capacitor RVCC1.

[0037] Pin 28 of chip U1 provides the power required for the normal operation of the internal circuitry, ensuring the stable operation of the internal logic circuitry, control circuitry, etc.

[0038] The above embodiments are only used to illustrate the technical solution of this utility model, and are not intended to limit it. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A lithium battery charge and discharge protection circuit with shutdown protection, characterized in that, include: Charging protection module, overcharge and over-discharge protection module, overcurrent detection module and power supply module; The charging protection module includes a chip U1, and the overcharge and over-discharge protection module, the overcurrent detection module, and the power module are all electrically connected to the chip U1. Specifically, the overcurrent detection module is electrically connected to MOSFETs Q6.1 and Q6.

2. The drain (D) of MOSFET Q6.1 is electrically connected to the source (S) of MOSFET Q6.

2. A capacitor C6, a capacitor C7, a resistor RS4, and a Zener diode U2 are electrically connected between MOSFETs Q6.1 and Q6.

2. The other end of capacitor C7 is electrically connected to the source (S) of MOSFET Q7. The other end of resistor RS4 is electrically connected to resistor RS3. Resistor RS4 is connected in parallel with Zener diode U2. The other end of resistor RS3 is electrically connected to the source (S) of MOSFET Q8. A resistor RS2 is electrically connected to the gate (G) of MOSFET Q8. Resistor RS2, MOSFET Q7, and MOSFET Q6.1 are connected in parallel. The resistor RS2, the drain of the MOSFET Q8, the resistor RCO1, the gate and drain of the MOSFET Q7, the resistor RS1, and the source of the MOSFET Q6.1 are all connected to the main power circuit of the power module through the diode DIN1.

2. The lithium battery charging and discharging protection circuit with shutdown protection according to claim 1, characterized in that: The overcharge and over-discharge protection module includes resistors R7 and R8. Resistor R7 is electrically connected to pin 2 of chip U1, and resistor R8 is electrically connected to pin 3 of chip U1. The other ends of resistors R7 and R8 are both electrically connected to the power module through resistor RVCC1.

3. The lithium battery charging and discharging protection circuit with shutdown protection according to claim 1, characterized in that: The overcurrent detection module includes capacitors COV1, COVD1, COVC1, COVC2, resistors RNTC1, RTRH1, RVM1, diode D7, resistors RDO1, RCO1, RS1, RVIN1, and capacitor CVIN1. Specifically, pin 4 of chip U1 is electrically connected to capacitor COV1 and then grounded; pin 5 of chip U1 is electrically connected to capacitor COVD1 and then grounded; pin 6 of chip U1 is electrically connected to capacitor COVC1 and then grounded; pin 7 of chip U1 is electrically connected to capacitor COVC2 and then grounded; pin 8 of chip U1 is electrically connected to resistor RNTC1 and then grounded; pin 9 of chip U1 is electrically connected to resistor RTRH1 and then grounded; pin 10 of chip U1 is electrically connected to resistor RVM1 and then electrically connected to the power module; pin 11 of chip U1 is electrically connected to diode D7; and the pins of chip U1... 12 is electrically connected to the resistor RDO1. The other end of the diode D7 is electrically connected to the resistor RCO1, the resistor RS1, the gate of the MOSFET Q6.1, and the resistor RDO1. The other end of the resistor RDO1 is electrically connected to the gate of the MOSFET Q6.

2. The other end of the resistor RCO1 is electrically connected to the gate of the MOSFET Q7. The other end of the resistor RS1 is electrically connected between the drain of the MOSFET Q7 and the source of the MOSFET Q6.

1. Pin 14 of the chip U1 is electrically connected to the resistor RVIN1 and the capacitor CVIN1. There is a resistor Rsense1 between the resistor RVIN1 and the capacitor CVIN1.

4. The lithium battery charging and discharging protection circuit with shutdown protection according to claim 1, characterized in that: The power module is composed of several power supply units connected in series; Specifically, the positive terminal of one of the power supply units BT1 is electrically connected to pin 19 of the chip U1. A resistor RD1 is electrically connected between the power supply unit BT1 and pin 19 of the chip U1. The other end of the resistor RD1 is electrically connected to the drain (D) terminal of the MOSFET Q1. The gate (G) terminal of the MOSFET Q1 is electrically connected to pin 18 of the chip U1 through a resistor RG1. Pin 17 of the chip U1 is electrically connected to the resistor RG1 through a capacitor C1. Pin 17 of the chip U1 is electrically connected to the source (S) terminal of the MOSFET Q1 and then grounded.

5. The lithium battery charging and discharging protection circuit with shutdown protection according to claim 2, characterized in that: Pin 28 of the chip U1 is electrically connected between resistor R7 and capacitor RVCC1.

Images