Battery management system

Abstract

The invention discloses a battery management system, which is applied to a battery system, the battery system comprises a battery pack, and the battery pack comprises a plurality of batteries connected in series and is used for providing electric energy for a load; the battery management system comprises a control device, the control device comprises a main control unit, a micro-control unit, a secondary protection circuit, a positive end discharge NMOS drive control circuit, a sleep activation circuit and an optocoupler isolation circuit, and the main control unit comprises a charge and discharge control circuit; wherein the dormancy activation circuit is used for waking up the battery system when receiving an activation signal; the charge-discharge control circuit is used for controlling a charge path and a discharge path of the battery pack; and the positive end discharge NMOS driving control circuit is used for driving a switch of an MOSFET in the charge and discharge control circuit according to the control signal of the micro-control unit. The battery management system can effectively control the charging and discharging process of the battery and ensure the safety and stability of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management, and particularly to a battery management system. Background Art

[0002] With the rapid development of fields such as electric vehicles, energy storage systems, and portable electronic devices, lithium batteries, as an efficient and environmentally friendly energy storage device, have been widely used. Lithium batteries have advantages such as high energy density, long cycle life, and low self-discharge rate. However, their safety, stability, and life management are still important technical challenges. Especially in a battery pack composed of multiple series-connected lithium batteries, due to the inconsistencies between battery cells (such as capacity, internal resistance, self-discharge rate, etc.), it is easy to cause problems such as voltage imbalance, overcharging, over-discharging, and overcurrent during the charging and discharging process of the battery pack, which will affect the performance and life of the battery pack and even pose safety hazards.

[0003] Existing battery management systems usually monitor parameters such as the voltage, current, and temperature of the battery pack to achieve charge and discharge control and protection of the battery. However, traditional battery management systems have the following problems:

[0004] 1. Imprecise charge and discharge control: Traditional charge and discharge control circuits usually use a single MOSFET to control the charge and discharge path, lacking precise control over the charge and discharge process, which easily leads to overcharging or over-discharging of the battery and affects the battery life.

[0005] 2. Single protection mechanism: Existing battery management systems usually only have a primary protection mechanism (such as overvoltage and undervoltage protection), lacking multiple protection designs and unable to effectively handle complex battery abnormal situations, presenting safety hazards.

[0006] 3. High power consumption: Traditional battery management systems have high power consumption in the standby or sleep mode, resulting in an increased self-discharge rate of the battery and shortening the storage time of the battery.

[0007] 4. The communication interface is vulnerable to interference: The communication interface between the battery management system and external devices usually lacks effective isolation protection, is easily affected by high voltage or current shocks, resulting in damage to the communication interface and affecting the reliability of the system.

[0008] Therefore, this application proposes a battery management system. Summary of the Invention

[0009] The purpose of the present invention is to provide a battery management system that can effectively control the charge and discharge process of the battery and ensure the safety and stability of the battery.

[0010] The purpose of the present invention is achieved by the following technical solutions:

[0011] The present invention provides a battery management system, which is applied to a battery system. The battery system includes a battery pack, and the battery pack includes a plurality of serially connected batteries for supplying electrical energy to a load.

[0012] The battery management system includes: a control device, which includes a main control unit, a micro-control unit, a secondary protection circuit, a positive terminal discharge NMOS drive control circuit, a sleep activation circuit, and an opto-coupler isolation circuit. The main control unit includes a charge and discharge control circuit.

[0013] Among them, the sleep activation circuit is used to wake up the battery system when receiving an activation signal; the charge and discharge control circuit is used to control the charging path and discharging path of the battery pack; the positive terminal discharge NMOS drive control circuit is used to drive the switching of the MOSFET in the charge and discharge control circuit according to the control signal of the micro-control unit.

[0014] The beneficial effects of the above solution include: By integrating a sleep activation circuit, a charge and discharge control circuit, and a positive terminal discharge NMOS drive control circuit, the present invention realizes the intelligent management of the battery system, can effectively control the charging and discharging process of the battery, and ensures the safety and stability of the battery. Through the secondary protection circuit and the opto-coupler isolation circuit, the present invention provides multiple protection mechanisms to prevent problems such as overcharging, over-discharging, and over-current of the battery, and improves the safety and reliability of the system. Through the control signal of the micro-control unit, the present invention can accurately control the switching state of the MOSFET to achieve efficient power distribution and battery management.

[0015] Further, the battery system further includes:

[0016] A charger, which is used to charge the battery pack.

[0017] The beneficial effects of the above solution include: The present invention charges the battery pack through the charger to ensure that the battery pack can be quickly charged when needed, improving the convenience and efficiency of system use. In addition, by setting the charger, it can be avoided that the battery pack is damaged due to overcharging or undercharging, and the service life of the battery is extended.

[0018] Further, the charge and discharge control circuit includes: a main control integrated circuit, and the main control integrated circuit includes:

[0019] MOSFET Q1, which is used to control the discharging path of the battery pack. When MOSFET Q1 is turned on, the current flows from the positive pole of the battery pack to the positive pole of the battery pack for discharging, realizing the distribution of power.

[0020] The beneficial effects of the above solution include: In the present invention, the MOSFET Q1 controls the discharge path of the battery pack, ensuring that the current flows from the positive pole of the battery pack to the positive discharge terminal, realizing the reasonable distribution of power supply, and avoiding damage to the battery pack due to over-discharge. In addition, the on and off of the MOSFET Q1 can respond quickly, ensuring the efficiency and stability of power supply distribution.

[0021] Further, the gate of the MOSFET Q1 is connected to the discharge enable signal pin through the resistor R1 and the resistor R2. The drain of the MOSFET Q1 is connected to the positive pole of the battery pack, and the source of the MOSFET Q1 is connected to the load.

[0022] The beneficial effects of the above solution include: In the present invention, by connecting the gate of the MOSFET Q1 through the resistors R1 and R2, the current can be effectively limited, preventing the MOSFET from being damaged due to excessive current, and improving the reliability and safety of the circuit. In addition, the gate of the MOSFET Q1 is controlled through the discharge enable signal pin, which can accurately control the switching state of the MOSFET and ensure the stability of the discharge path.

[0023] Further, the positive terminal discharge NMOS drive control circuit:

[0024] In response to the power supply being powered on and the charge pump being powered on for a preset duration, it drives the MOSFET of the main control unit to conduct and perform positive terminal discharge.

[0025] The beneficial effects of the above solution include: In the present invention, through the positive terminal discharge NMOS drive control circuit, after the power supply is powered on and the charge pump is powered on, it delays for a preset duration before driving the MOSFET to conduct, ensuring the power supply stability and avoiding circuit anomalies caused by the power supply not being fully stable. In addition, the design of delayed conduction can effectively prevent misoperations and ensure that the circuit performs discharge operations after the power supply is fully stable.

[0026] Further, the microcontroller unit control signals include the MCU_CPEN signal and the MCU_PMONEN signal;

[0027] The MOSFETs in the charge and discharge control circuit include a charging MOSFET and a discharging MOSFET;

[0028] When the MCU_CPEN signal is at a high level, the CHG_EN signal is valid, and the charging MOSFET conducts, and the battery is charged;

[0029] When the MCU_PMONEN signal is at a high level, the DSG_EN signal is valid, and the discharging MOSFET conducts, and the battery discharges.

[0030] The beneficial effects of the above solution include: By using the MCU_CPEN signal and the MCU_PMONEN signal to control the charging MOSFET and the discharging MOSFET respectively, the present invention realizes the separate control of the charging and discharging paths, ensuring the safety and stability of the charging and discharging processes. In addition, the charging and discharging paths are dynamically controlled according to the battery state to avoid overcharging or over-discharging of the battery and extend the battery life.

[0031] Further, the sleep activation circuit includes:

[0032] An activation signal input terminal for receiving an activation signal, where the activation signal includes a low-level activation signal or a key signal;

[0033] MOSFET Q10 for controlling the power enable signal;

[0034] MOSFET Q11 for controlling the activation signal;

[0035] When no activation signal is received, MOSFET Q10 conducts, and the battery system is in the sleep mode;

[0036] When an activation signal is received, MOSFET Q11 conducts, and the battery system is in the activation mode.

[0037] The beneficial effects of the above solution include: With the sleep activation circuit of the present invention, when the system does not receive an activation signal, MOSFET Q10 conducts, the system enters the sleep mode, reducing the self-power consumption and extending the battery storage time. When an activation signal is received, MOSFET Q11 conducts, the system wakes up quickly and resumes the normal working state, improving the response speed of the system and the user experience.

[0038] Further, the optocoupler isolation circuit is used for communication between the microcontroller unit and the main control unit;

[0039] When the main control unit sends data to the microcontroller unit, MOSFET Q5 converts the signal level into a level that the microcontroller unit can receive.

[0040] The beneficial effects of the above solution include: Through the optocoupler isolation circuit, the present invention realizes signal isolation between the microcontroller unit and the main control unit, preventing high voltage or current surges from damaging the communication interface and improving the safety and reliability of the system. In addition, MOSFET Q5 converts the signal level into a level that the microcontroller unit can receive, ensuring the accuracy and stability of signal transmission.

[0041] Further, the secondary protection circuit includes:

[0042] When the battery voltage exceeds the secondary protection voltage setting value, secondary protection is triggered to cut off the charging path or trigger the fuse to prevent overcharging of the battery.

[0043] The beneficial effects of the above solution include: Through the secondary protection circuit in the present invention, when the battery voltage exceeds the set value of the secondary protection voltage, the secondary protection is triggered to cut off the charging path or trigger the fuse, preventing the battery from overcharging and improving the safety of the system. In addition, the secondary protection circuit and the primary protection circuit of the main control unit form a dual protection mechanism to ensure the safe operation of the battery under various abnormal conditions.

[0044] Further, the secondary protection circuit includes a zener diode, one end of the zener diode is connected to the positive pole of the battery pack, and the other end of the zener diode is connected to the ground;

[0045] The output end of the secondary protection circuit is used to output a protection status output signal;

[0046] When the voltage of the battery pack is lower than the set value of the secondary protection voltage, the protection status output signal is a low-level signal and the circuit works normally;

[0047] When the voltage of the battery pack is greater than or equal to the set value of the secondary protection voltage, the zener diode conducts to limit the voltage rise, and the protection status output signal is in a high-impedance state, triggering the protection mechanism of the circuit.

[0048] The beneficial effects of the above solution include: The present invention limits the voltage rise through the zener diode. When the battery voltage exceeds the set value, the zener diode conducts to limit the voltage rise and prevent the battery from overcharging.

[0049] Status indication: Through the protection status output signal, the working status of the circuit can be indicated in real time. When the protection mechanism of the circuit is triggered, a high-impedance state signal is output, which is convenient for system monitoring and maintenance.

[0050] Compared with the prior art, the beneficial effects of the present invention at least include:

[0051] The present invention realizes the intelligent management of the battery system by integrating a sleep activation circuit, a charge and discharge control circuit, and a positive terminal discharge NMOS drive control circuit, can effectively control the charge and discharge process of the battery, and ensure the safety and stability of the battery. The present invention provides a multiple protection mechanism through the secondary protection circuit and the optocoupler isolation circuit to prevent problems such as overcharging, over-discharging, and over-current of the battery, and improves the safety and reliability of the system. The present invention can accurately control the switching state of the MOSFET through the control signal of the microcontroller unit to achieve efficient power distribution and battery management. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is a circuit schematic diagram of the main control unit of an embodiment of the present invention.

[0053] Figure 2It is a circuit schematic diagram of the micro - control unit according to an embodiment of the present invention.

[0054] Figure 3 It is a circuit schematic diagram of the secondary protection circuit according to an embodiment of the present invention.

[0055] Figure 4 It is a circuit schematic diagram of the positive - terminal discharge NMOS drive control circuit according to an embodiment of the present invention.

[0056] Figure 5 It is a circuit schematic diagram of the sleep activation circuit according to an embodiment of the present invention.

[0057] Figure 6 It is a circuit schematic diagram of the opto - coupler isolation circuit according to an embodiment of the present invention.

[0058] Figure 7 It is a structural schematic diagram of the battery management system according to an embodiment of the present invention. Detailed implementation manners

[0059] Now, the exemplary embodiments will be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this invention will be more complete and comprehensive, and will fully convey the concept of the exemplary embodiments to those skilled in the art. Like reference numerals in the figures denote the same or similar structures, and thus their repeated description will be omitted.

[0060] The words expressing positions and directions described in the present invention are all illustrated by taking the accompanying drawings as examples, but can also be changed according to needs, and all the changes made are included in the protection scope of the present invention.

[0061] The battery management system of the present invention is applied to a battery system. The battery system includes a battery pack and a charger. The charger is used to charge the battery pack. The battery pack includes a plurality of batteries connected in series and is used to provide electrical energy for a load. For example: B1, B2, B3, and B4 connected in series. Among them, the battery is a lithium battery.

[0062] Refer to Figure 7 , the battery management system of the present invention includes: a control device. Further, the battery management system may also include a display module, a communication module, and an alarm module.

[0063] During application, the control device is used to implement over - voltage, under - voltage, over - current during charge and discharge, high temperature during charge, and low temperature during discharge protection functions for the battery pack. Preferably, it also has a battery equalization function. The display module is used to display the voltage, current, temperature, power, remaining capacity, and remaining battery life of the battery pack. The communication module is used for the battery management system to communicate with external devices. The alarm module is used to emit an alarm signal when the battery voltage, current, or temperature is abnormal.

[0064] The control device of the present invention includes a main control unit. Further, the control device may further include: a micro control unit and a secondary protection circuit. Further, the control device may further include: a positive terminal discharge NMOS drive control circuit, a sleep activation circuit, and an optocoupler isolation circuit.

[0065] In application, the main control unit is mainly used to control the power distribution and the charging and discharging of the battery. Through the combination of MOSFETs, capacitors, resistors, and diodes, functions such as power distribution, filtering and voltage regulation, current limiting protection, and reverse current protection are achieved. The micro control unit is used to collect the voltage, current, temperature, power, remaining capacity, and remaining battery life of the battery pack. The secondary protection circuit is used to provide additional overvoltage protection during the battery charging process to ensure that the voltage of the battery pack is within a safe range. The positive terminal discharge NMOS drive control circuit is used to drive the switching of the MOSFET in the charge and discharge control circuit according to the control signal of the micro control unit. The sleep activation circuit is used to wake up the battery system when an activation signal is received. The optocoupler isolation circuit is used for communication between the micro control unit and the main control unit.

[0066] In actual application, the main control unit realizes multiple protections for the battery pack, such as overvoltage, undervoltage, overcurrent during charging and discharging, high temperature during charging, and low temperature during discharging, through the positive terminal protection circuit. In addition, the main control unit has a battery equalization function, which is used to balance the voltages of each battery cell to prevent the battery pack from being damaged due to voltage imbalance. The secondary protection circuit provides secondary protection when the primary protection against overvoltage during charging by the main control unit fails. Among them, the set value of the primary protection voltage is less than the set value of the secondary protection voltage.

[0067] Reference Figure 1 Referring to

[0068] In application, the main control integrated circuit FKD3006 is used to execute the main control functions of the circuit, such as controlling the on and off of the current. The auxiliary integrated circuit FKD3115 is connected beside the main control integrated circuit FKD3006 and is used to provide additional control functions or signal processing. The power input terminal (such as the positive terminal B+ of the battery pack) is used to receive external power input. The ground terminal is used to connect to the common ground potential of the circuit. The charge and discharge different port output circuit is used to control the discharge path and the charging path of the battery pack. The battery interface BAT1 is used to connect an external battery as the power source. The fast blow fuse is used to cut off the circuit in case of overcurrent. The communication interface is used for data communication with external devices.

[0069] In actual application, the main control integrated circuit FKD3006 and the auxiliary integrated circuit FKD3115 cooperate with each other through connecting wires and electronic components to achieve precise control and signal processing functions of the circuit.

[0070] The main control integrated circuit FKD3006 of the present invention includes: MOSFET Q1. Further, it also includes: MOSFET Q7. Further, it also includes: a plurality of capacitors and one or more diodes.

[0071] The MOSFET Q1 of the present invention is used to control the discharge path of the battery pack. When MOSFET Q1 is turned on, current flows from the positive electrode B+ of the battery pack to the positive discharge electrode P+ of the battery pack, realizing power distribution.

[0072] During application, the gate of MOSFET Q1 is connected to the discharge enable signal pin DMOS_EN through resistor R1 and resistor R2. The drain of MOSFET Q1 is connected to the positive electrode B+ of the battery pack, and the source of MOSFET Q1 is connected to the load. Among them, resistor R1 is 10MΩ and resistor R2 is 5Ω, which are used for current limiting to prevent excessive current from damaging the MOSFET.

[0073] In actual application, MOSFET Q1 has a low on-resistance and a high switching speed, and is suitable for high-power discharge control.

[0074] The MOSFET Q7 of the present invention is set to a specification of 72V / 30A and is used to quickly cut off the circuit when the circuit has an overload or a short circuit, protecting the circuit and other components from damage.

[0075] During application, when the current in the circuit exceeds the set value of 72V / 30A, MOSFET Q7 can quickly respond and cut off the circuit, thus effectively preventing circuit components from being damaged due to overload and improving the reliability and safety of the entire circuit.

[0076] In actual application, MOSFET Q7 is used to control the current path. When MOSFET Q7 is turned on, current flows from the power input to the load, realizing power distribution.

[0077] A plurality of capacitors (such as capacitor C51 and capacitor C52) of the present invention are respectively connected to the positive electrode B+ of the battery pack and the ground GND, and are used to smooth the voltage fluctuation of the battery pack and prevent voltage mutation from affecting the circuit.

[0078] During application, the capacitance value of the capacitors is 100nF / 50V, which is used for high-frequency filtering to prevent high-frequency noise from interfering with the circuit.

[0079] One or more diodes (such as diode D1) of the present invention are connected to the positive electrode B+ of the battery pack and the ground GND, and are used to prevent reverse current from damaging the circuit.

[0080] When applied, the diode D1 is of the 1N5819 model, which has a low forward voltage drop and a high reverse voltage withstand, and is suitable for protecting the circuit.

[0081] The discharge enable signal interface DMOS_EN of the present invention is used to receive an external control signal (such as a discharge enable signal) to control the switching state of the MOSFET in the circuit, such as starting or closing.

[0082] When applied, a discharge enable signal interface DMOS_EN is connected to the gate of the MOSFET Q1 through the resistor R2 to control the switching state of the MOSFET Q1. Another discharge enable signal interface DMOS_EN is connected to the gate of the MOSFET Q7 through the resistor R75 to control the switching state of the MOSFET Q7.

[0083] In actual application, the discharge enable signal is generated by the microcontroller unit. After the discharge enable signal interface DMOS_EN receives the discharge enable signal, it dynamically controls the discharge path according to the battery state. When the discharge enable signal is at a high level, the discharge enable signal interface DMOS_EN controls the corresponding MOSFET to conduct, and the current flows from the power input to the load, realizing the distribution of the power supply.

[0084] The charge and discharge different-port output circuit of the present invention includes the negative pole P- of the battery pack, the discharge positive pole P+ of the battery pack, and the charge positive pole C+ of the battery pack. The negative pole P- of the battery pack is connected to the reference ground of the CW1573, the discharge positive pole P+ of the battery pack is connected to the discharge MOSFET, and the charge positive pole C+ of the battery pack is connected to the charge MOSFET.

[0085] When applied, the charge and discharge different-port output circuit reduces the cost of the MOSFET through the separated discharge positive pole P+ and charge positive pole C+. For example: a high-power MOSFET is used for the discharge path, and a low-power MOSFET is used for the charge path.

[0086] In actual application, when the voltage of any single battery exceeds the set value (such as 4.25V), the main control IC turns off the charge MOSFET to stop charging. When the voltage of any single battery is lower than the set value (such as 2.8V), the main control IC turns off the discharge MOSFET to stop discharging. The voltage of each battery is balanced through the balancing circuit to prevent the battery pack from being damaged due to voltage imbalance. The fast-blow fuse F1 of the present invention is connected to the positive pole B+ of the battery pack, and the rated current is 30A, which is suitable for high-power discharge scenarios and cuts off the circuit in case of overcurrent to protect the battery and the load.

[0087] The communication interface of the present invention is the communication interface UART.

[0088] During application, the communication interface UART is connected to the microcontroller unit for data communication with external devices.

[0089] In actual application, the communication interface UART is connected to the microcontroller unit through an opto-isolation circuit to prevent high voltage or current surges from damaging the communication interface and to control the charging and discharging paths of the battery.

[0090] The positive terminal discharge NMOS drive control circuit of the present invention is used to protect the positive terminal of the battery pack and drive the MOSFET switch in the charge and discharge control circuit according to the control signal.

[0091] During application, refer to Figure 4 , the positive terminal discharge NMOS drive control circuit uses the CW1005 chip. The CW1005 chip is used to receive an external power supply and output a power supply voltage. The pin VDDCP is connected to the charge pump for generating or regulating the voltage.

[0092] In response to the power supply being powered on and the charge pump being powered on for a preset duration, the MOSFET of the main control unit is driven to conduct for positive terminal discharge. Specifically, after the power supply is powered on and the charge pump is powered on, in order to ensure power supply stability and avoid circuit abnormalities caused by turning on the NMOS transistor when the power supply is not fully stable, it is necessary to wait for a period of time (such as 150 ms) before turning on the NMOS transistor for positive terminal discharge operation.

[0093] In actual application, the CW1005 chip has a CHG pin, the CHG pin is connected to the charging MOSFET for realizing power supply charging; it has a battery pin BAT, the battery pin is connected to the power supply as the energy supply of the circuit; it has a CP_EN pin, the CP_EN pin collects the MCU CPEN signal, and the MCU CPEN signal comes from the microcontroller unit; it has a CHG_EN pin, the CHG_EN pin collects the enable signal for controlling the CHG pin; it has a PCHG pin, the PCHG pin is connected to the CHG pin and the CP_EN pin for controlling power supply charging. Further, the CHG pin is connected to the pre-charge MOSFET; it has a DSG pin, the DSG pin collects the DMOS EN signal for controlling the switching state of the NMOS transistor. Further, the DSG pin is connected to the discharge MOSFET. Preferably, an OR gate circuit is also provided on the CW1005 chip for combining multiple signals; resistors are provided on some pins, such as resistor R61 and resistor R62, for voltage division and current limiting to prevent excessive current from damaging components; capacitors are provided on some pins, such as capacitor C45 and capacitor C47, and the circuit can smooth the voltage fluctuation of the battery pack to prevent voltage mutations from affecting the circuit.

[0094] In the actual application process, the CW1005 chip can collect DO signals, where the DO signals are output signals or detection signals; it can collect the MCU PMONEN signal, and the MCU PMONEN signal is used to control the enabling of the power monitoring function; it can collect the PMONEN signal, and the PMON EN signal is the output or control signal of the power monitoring function; it can collect the PACKDIV signal, and the PACKDIV signal is used to control the voltage division or detection function of the battery pack; it can collect the PCHG_EN signal, and the PCHG_EN signal is used to control the enabling of the PCHG component.

[0095] In a preferred embodiment, both the MCU_CPEN signal and the MCU_PMONEN signal are control signals of the microcontroller unit, which are used to control the charging path and the discharging path. The MOSFETs in the charge and discharge control circuit include a charging MOSFET and a discharging MOSFET. When the MCU_CPEN signal is at a high level, the CHG_EN signal is valid, the charging MOSFET conducts, and the battery starts charging. When the MCU_PMONEN signal is at a high level, the DSG_EN signal is valid, the discharging MOSFET conducts, and the battery starts discharging. It can be seen that through the CW1005 chip and the MCU_CPEN signal, the circuit can control the charging process of the battery to ensure charging safety; through the CW1005 chip and the MCU_PMONEN signal, the circuit can control the discharging process of the battery to ensure discharging safety.

[0096] The sleep activation circuit of the present invention is used to wake up the battery system when an activation signal is received. When a low-level signal or a key press is received, the activation circuit wakes up the battery system; when the activation signal is not received, the system enters the sleep mode.

[0097] During application, the sleep activation circuit includes an activation signal input terminal and a sleep control module. The activation signal input terminal is used to receive the activation signal, and the activation signal includes a low-level activation signal or a key signal; the sleep control module is used to make the battery system enter the sleep mode when the low-level activation signal or the key signal is not received to reduce the self-power consumption and extend the battery storage time.

[0098] During actual application, refer to Figure 5, the sleep activation circuit uses the SIO3401 chip. The sleep activation circuit also includes MOSFET Q10 and MOSFET Q11. MOSFET Q10 is used to control the power enable signal, and MOSFET Q11 is used to control the activation signal. MOSFET Q10 is connected to the output terminal of the SIO3401 chip and is used to control the power enable signal. Specifically, the G terminal (gate) of MOSFET Q10 is connected to ZD3 and AFE_LDO_SRC, the D terminal (drain) of MOSFET Q10 is connected to POWER_EN, and the S terminal (source) of MOSFET Q10 is connected to the ground GND. MOSFET Q11 is connected to the output terminal of the SIO3401 chip and is used to control the activation signal. Specifically, the G terminal (gate) of MOSFET Q11 is connected to R101 and R104, the D terminal (drain) of MOSFET Q11 is connected to D11 and P, and the S terminal (source) of MOSFET Q11 is connected to R99 and the ground GND.

[0099] Furthermore, the SIO3401 chip is provided with a manual activation element switch SW101 and a switch SW102. Specifically, when the switch is pressed, the system is activated. In addition, multiple resistors (such as resistor R90, resistor R93) are provided at the output terminal of the SIO3401 chip for current limiting and voltage division; at least one capacitor (such as capacitor C69, C68) is provided at the output terminal of the SIO3401 chip for storing charge, smoothing voltage or filtering out clutter.

[0100] During the actual application process, the transient voltage suppressor ZD3 is connected to the G terminal (gate) of MOSFET Q10 and AFE_LDO_SRC for current limiting, preventing excessive current from damaging the MOSFET and protecting the circuit from transient overvoltage damage. Preferably, an AFE LDO SRC low-noise amplifier linear voltage regulator can also be set to provide a stable power supply voltage for the sleep activation circuit.

[0101] In some embodiments, the sleep activation circuit is used to control the power enable signal POWER_EN. When the system does not receive the activation signal, MOSFET Q10 conducts, POWER_EN is at a low level, and the system enters the sleep mode to reduce self-power consumption; when MOSFET Q10 is cut off, POWER_EN is at a high level, and the system wakes up.

[0102] In some embodiments, the sleep activation circuit is used to control the activation signal. When the activation signal (such as SW101 or SW102 is pressed) is received, MOSFET Q11 is turned on, the system is activated, POWER_EN is at a high level, and the system resumes normal operation; when MOSFET Q11 is turned off, the system enters the sleep mode. In the sleep state, by controlling the on / off of MOSFET Q10, the power consumption of the circuit can be effectively reduced, achieving an energy-saving effect.

[0103] It can be seen that through MOSFET Q10 and the POWER_EN signal, the sleep mode of the control system is controlled, the self-power consumption is reduced, and the battery storage time is extended. Through MOSFET Q11 and the manual switch, the activation mode of the control system is controlled to ensure that the system can be quickly awakened when needed. Through the AFE_LDO_SRC and POWER_EN signals, the power switch of the system is managed to ensure the power stability of the system in the sleep and activation modes.

[0104] The optocoupler isolation circuit of the present invention is used for communication between the microcontroller unit and the main control unit to isolate the serial communication interface and prevent damage to the communication interface caused by high voltage or current impact. For example: communication interface Rx and communication interface Tx.

[0105] During application, refer to Figure 6 The optocoupler isolation circuit uses an LTV356TD chip. The LTV356TD chip is provided with an MCU_TX1 interface, which is the transmission signal line of the MCU and is used to send data to the BMS; it is provided with an MCU_RX1 interface, which is the reception signal line of the MCU and is used to receive data from the BMS; it is provided with a BMS_TX interface, which is the transmission signal line of the BMS and is used to send data to the MCU; it is provided with a BMS_RX interface, which is the reception signal line of the BMS and is used to receive data from the MCU.

[0106] During actual application, a MOSFET Q5 is provided at the input end and / or output end of the LTV356TD chip. The G terminal (gate) of MOSFET Q5 is connected to the output end of the optocoupler, the D terminal (drain) is connected to MCU_RX1, and the S terminal (source) is connected to the ground GND. It can be seen that MOSFET Q5 is used for signal level conversion, converting the signal output by the optocoupler into a level that can be received by the microcontroller unit.

[0107] In some embodiments, the micro-control unit sends data to the main control unit: the micro-control unit sends data through MCU_TX1. After being limited in current by resistor R39, the data enters the A terminal of U5. U5 converts the electrical signal into an optical signal and then outputs it through the C terminal to BMS_RX, completing the data transmission. In some other embodiments, the main control unit sends data to the micro-control unit: the main control unit sends data through BMS_TX. After entering through the C terminal of U5, U5 converts the optical signal into an electrical signal and outputs it through the C terminal of U7 to the G terminal of MOSFET Q5. MOSFET Q5 converts the signal level into a level that the micro-control unit can receive and outputs it through the D terminal of MOSFET Q5 to MCU_RX1, completing the data reception. It can be seen that through the combination of the optocoupler and MOSFET, the circuit realizes signal isolation and level conversion, ensuring the secure and reliable communication between the micro-control unit and the main control unit.

[0108] Reference Figure 2 , the micro-control unit of the present invention uses a microcontroller MCU. The micro-control unit can receive signals of different voltage nodes through a resistor network (such as resistors R50, R51, R49, and R52) and the MCU World Node pin, and perform status judgment or control. Specifically, by monitoring the CU World Node pin and limiting the current and dividing the voltage through the resistor network, it can ensure that the voltage is within a safe range and prevent excessive current from damaging the micro-control unit or other components.

[0109] During application, the micro-control unit can also control the working state of the MOSFET drive circuit according to the collected data to implement functions such as overvoltage protection, undervoltage protection, overcurrent protection, and temperature protection. In addition, the micro-control unit is also used to implement feedback control according to the voltage and current signals of the battery pack to ensure that the battery pack operates within a safe range.

[0110] During actual application, the micro-control unit is provided with a battery input control terminal for receiving the input voltage, current, and temperature signals of the battery.

[0111] The battery input control terminal integrates: a voltage detection module, a current detection module, and a temperature detection module. Further, the battery input control terminal also integrates: a power detection module, a remaining capacity detection module, and a battery life detection module. Among them, the voltage detection module is used to detect the voltage of the battery pack; the current detection module is used to detect the current of the battery pack. The temperature detection module is used to detect the temperature of the battery pack and trigger a protection mechanism when the temperature exceeds the set value. The power detection module is used to detect the power of the battery pack and trigger a low-power protection when the power is lower than the set value. The remaining capacity detection module is used to detect the remaining capacity of the battery pack and trigger a warning signal when the remaining capacity is lower than the set value. The battery life detection module is used to detect the remaining life of the battery pack and trigger a replacement prompt when the remaining life is lower than the set value.

[0112] Reference Figure 3 For the secondary protection circuit of the present invention, the CW1071 chip is adopted. By integrating a voltage stabilizing diode, voltage dividing resistors and filter capacitors, it can effectively limit the voltage rise and trigger the protection mechanism under overvoltage. Specifically, when the battery voltage exceeds the set value of the secondary protection voltage, the secondary protection circuit triggers secondary protection, cuts off the charging path or triggers the fuse to prevent overcharging of the battery.

[0113] During application, the voltage detection points of the secondary protection circuit are connected to each battery of the battery pack to detect the voltage of each battery; the output terminal of the secondary protection circuit outputs a protection status output signal CO2. In addition, the secondary protection circuit includes multiple capacitors for filtering and voltage stabilization; includes multiple resistors for voltage division and current limiting; includes a voltage stabilizing diode ZD2 for limiting the voltage in the circuit to prevent overvoltage.

[0114] The secondary protection circuit ensures that the voltage of the battery pack is within a safe range through the voltage stabilizing diode ZD2 and the voltage dividing resistor network (such as resistor R70) to prevent overvoltage from damaging the circuit. Through the capacitor network (such as capacitor C53), it smooths the voltage fluctuation of the battery pack to prevent the impact on the circuit caused by voltage mutation. Through the protection status output signal CO2, it indicates the working state of the circuit, that is, normal or protection.

[0115] Specifically, the resistance value of the resistor R70 is 200Ω. One end is connected to the positive electrode B+ of the battery pack, and the other end is connected to the VDD1 pin for current limiting to prevent excessive current from damaging the subsequent circuit. The capacitor C53 is a 100mF / 50V capacitor. One end is connected to the positive electrode B+ of the battery pack, and the other end is connected to the ground GND for filtering and voltage stabilization to smooth the voltage fluctuation of the battery pack and prevent the impact on the circuit caused by voltage mutation. The voltage stabilizing diode ZD2 is a 24V voltage stabilizing diode. One end is connected to the positive electrode B+ of the battery pack, and the other end is connected to the ground GND. When the voltage of the battery pack exceeds 24V, the voltage stabilizing diode ZD2 will conduct, limit the voltage to 24V, and prevent overvoltage from damaging the circuit.

[0116] During actual application, when the voltage of the battery pack is within a safe range, the protection status output signal CO2 is a low-level signal, indicating that the circuit is working normally. When the voltage of the battery pack exceeds the set value of the secondary protection voltage (such as 24V), the voltage stabilizing diode ZD2 conducts, limits the voltage rise, and at the same time the protection status output signal CO2 is in a high-impedance state, indicating that the circuit triggers the protection mechanism, such as overvoltage protection.

[0117] In summary, the present invention realizes overvoltage, undervoltage, overcurrent, and temperature protection through CW1573 and CW1071; controls the charge and discharge path of the battery by driving the MOSFET switch; realizes the wake-up and sleep of the system through the activation circuit and the sleep control module, extending the battery storage time; collects data such as the voltage, current, and temperature of the battery, and adjusts the system working state according to the feedback signal; protects the communication interface through the optocoupler isolation circuit.

[0118] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Without departing from the principles and spirit of the present invention, those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the invention, and all such changes should fall within the protection scope of the claims of the present invention.

Claims

1. A battery management system, characterized in that: Applied to a battery system, the battery system comprises a battery pack, the battery pack comprises a plurality of lithium batteries connected in series, and is used to provide electrical energy to a load; The battery management system comprises: a control device, the control device comprises a main control unit, a micro control unit, a secondary protection circuit, a positive terminal discharge NMOS drive control circuit, a sleep activation circuit and an optical coupling isolation circuit, and the main control unit comprises a charge and discharge control circuit; Among them, the sleep activation circuit is used to wake up the battery system when receiving an activation signal; the charge and discharge control circuit is used to control the charging and discharging paths of the battery pack; the positive discharge NMOS drive control circuit is used to drive the switch of the MOSFET in the charge and discharge control circuit according to the micro-control unit control signal.

2. The battery management system according to claim 1, characterized in that: The battery system further comprises: A charger is used to charge the battery pack.

3. The battery management system according to claim 1, characterized in that: The charge and discharge control circuit comprises: a main control integrated circuit, and the main control integrated circuit comprises: MOSFET Q1 is used to control the discharge path of the battery pack. When MOSFET Q1 is turned on, the current flows from the positive electrode of the battery pack to the positive discharge electrode of the battery pack, thereby realizing power distribution.

4. The battery management system according to claim 3, characterized in that: The gate of the MOSFET Q1 is connected to the discharge enable signal pin through the resistor R1 and the resistor R2, the drain of the MOSFET Q1 is connected to the positive electrode of the battery pack, and the source of the MOSFET Q1 is connected to the load.

5. The battery management system according to claim 1, characterized in that: The positive end discharge NMOS drive control circuit: In response to the power supply being powered on and the charging pump being powered on for a preset period of time, the MOSFET of the main control unit is driven to be turned on to perform positive terminal discharge.

6. The battery management system according to claim 1, characterized in that: The micro-control unit control signal includes an MCU_CPEN signal and an MCU_PMONEN signal; The MOSFET in the charge and discharge control circuit includes a charging MOSFET and a discharging MOSFET; When the MCU_CPEN signal is high, the CHG_EN signal is valid, the charging MOSFET is turned on, and the battery is charged; When the MCU_PMONEN signal is high, the DSG_EN signal is valid, the discharge MOSFET is turned on, and the battery is discharged.

7. The battery management system according to claim 1, characterized in that: The dormancy activation circuit comprises: An activation signal input terminal, used to receive an activation signal, wherein the activation signal includes a low-level activation signal or a key signal; MOSFET Q10, used to control the power enable signal; MOSFET Q11, used to control the activation signal; When no activation signal is received, MOSFET Q10 is turned on and the battery system is in sleep mode; When receiving the activation signal, MOSFET Q11 is turned on and the battery system is in activation mode.

8. The battery management system according to claim 1, characterized in that: The optical coupling isolation circuit is used for communication between the micro control unit and the main control unit; When the main control unit sends data to the micro control unit, MOSFET Q5 converts the signal level into a level that the micro control unit can receive.

9. The battery management system according to claim 1, characterized in that: The secondary protection circuit comprises: When the battery voltage exceeds the secondary protection voltage setting value, the secondary protection is triggered to cut off the charging path or trigger the fuse to prevent the battery from overcharging.

10. The battery management system according to claim 9, characterized in that: The secondary protection circuit includes a voltage stabilizing diode, one end of which is connected to the positive electrode of the battery pack, and the other end of which is connected to the ground; The output end of the secondary protection circuit is used to output a protection status output signal; When the voltage of the battery pack is lower than the secondary protection voltage setting value, the protection status output signal is a low level signal and the circuit works normally; When the voltage of the battery pack is greater than or equal to the secondary protection voltage setting value, the Zener diode is turned on to limit the voltage rise, and the protection status output signal is in a high impedance state, and the circuit triggers the protection mechanism.

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