A lithium battery management system supporting high-side direct drive

Abstract

The utility model discloses a kind of lithium battery management systems supporting high side direct drive, including the main control chip MCU U1 connected by SPI communication protocol interaction, analog front-end acquisition chip U8, voltage acquisition equalization module, temperature acquisition module, current acquisition module, charge-discharge module and pre-charge-discharge module.The utility model utilizes single chip and can be 7-16 string battery sampling, equalization function, single overvoltage protection, single undervoltage protection, total voltage overvoltage protection and total voltage undervoltage protection, most can realize 8-way temperature detection to realize over-temperature low-temperature protection, better to circuit, cell temperature monitoring and protection;And in the current sampling function of setting, charging overcurrent protection and discharge overcurrent protection can be realized, and pre-charging function, pre-discharge function, load detection, charger detection and charge-discharge control and other functions are also collocated and set.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery management system technology, specifically a lithium battery management system that supports high-side direct drive. Background Technology

[0002] Lithium-ion batteries are a widely used type of rechargeable battery, particularly suitable for portable electronic devices and electric vehicles. These batteries are popular because of their high energy density, long lifespan, and relatively light weight.

[0003] With the widespread application of lithium-ion batteries in electric vehicles, energy storage systems, and consumer electronics, battery safety, lifespan, and efficiency have become key challenges. Battery Management Systems (BMS) need to monitor battery status (such as voltage, current, and temperature) in real time and provide protection against overcharge, over-discharge, and short circuits to ensure system safety and battery performance. Traditional BMSs often employ a low-side-drive architecture, where the protection circuit is located at the negative terminal of the battery. This architecture cannot cut off the current path when a ground short circuit occurs at the load end, allowing the battery to continue discharging through the short circuit point. This leads to drawbacks such as thermal runaway risk, high static power consumption, and poor anti-interference capability. High-side-drive architectures, on the other hand, have high system redundancy, high circuit cost, and low reliability. Therefore, we propose a lithium battery management system that supports direct high-side drive. Utility Model Content

[0004] The purpose of this invention is to provide a lithium battery management system that supports high-side direct drive, in order to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a lithium battery management system supporting high-side direct drive, characterized in that it includes: a main control chip MCU U1, an analog front-end acquisition chip U8, a voltage acquisition and equalization module, a temperature acquisition module, a current acquisition module, a charge-discharge module, and a pre-charge-discharge module, wherein the main control chip MCU U1 and the analog front-end acquisition chip U8, the voltage acquisition and equalization module, the temperature acquisition module, the current acquisition module, the charge-discharge module, and the pre-charge-discharge module are connected and interact via the SPI communication protocol;

[0006] The main control chip MCU U1 is used for system module resource allocation and data detection;

[0007] The analog front-end acquisition chip U8 is responsible for acquiring the battery's voltage, temperature, and current parameters, as well as processing pre-charge and discharge signals.

[0008] The voltage acquisition and equalization module is configured as a first voltage acquisition and equalization module and a second voltage acquisition and equalization module. The first voltage acquisition and equalization module and the second voltage acquisition and equalization module, together with the analog front-end acquisition chip U8, complete the real-time acquisition and equalization of the voltage of each battery string in the battery cluster.

[0009] The analog front-end acquisition chip U8 realizes 8-channel temperature sampling and processing, and realizes the functions of high temperature protection during charging, low temperature protection during charging, high temperature protection during discharging, and low temperature protection during discharging.

[0010] The current acquisition module is used to compare the voltage across the analog front-end acquisition chip U8 with the internal current of the analog front-end acquisition chip U8, sample the current, and realize the overcurrent protection function.

[0011] The charging and discharging module controls the on / off state of the charging and discharging MOSFETs according to the MCU's instructions, ensuring that the battery charges and discharges under safe conditions. It can also quickly respond to emergencies by cutting off the circuit to protect the battery from damage.

[0012] The pre-charge / discharge module is used to realize the pre-charge / discharge function of the battery.

[0013] Furthermore, the voltage acquisition and equalization module includes terminal J5, terminal J8, transistor Q34, transistor Q35, resistor R92, resistor R167, resistor R170, resistor R171 and capacitor C72. The first to fifteenth pins of terminal J5 are respectively connected to the positive and negative terminals of multiple battery strings in the battery cluster and the connection.

[0014] The sixth pin of terminal J8 is connected to the positive terminal BAT+ of the battery cluster, along with the positive terminal of the fifteenth battery string, the first pin of terminal J8, the second pin of terminal J8, the third pin of terminal J8, and the fourth pin of terminal J8.

[0015] The fifteenth pin of terminal J5 is connected to the emitter of transistor Q35 and resistor R171. The fourteenth pin of terminal J5 is connected to resistor R92, transistor Q34 and resistor R167. The other end of resistor R167 is connected to capacitor C72 and the thirteenth pin of analog front-end acquisition chip U8. The other end of resistor R92 is connected to the collector of transistor Q35. The base of transistor Q35 is connected to resistor R170. The other end of resistor R170 is connected to resistor R171, capacitor C72 and the fourteenth pin of analog front-end acquisition chip U8.

[0016] The fifth pin of terminal J8 is connected to resistor R28. The other end of resistor R28 is connected to the positive terminal BAT+ of the battery cluster through fuse F2. The other end of fuse F2 is connected to the anode of diode D11. The cathode of diode D11 is connected to transient voltage suppressor TVS5 and resistor R25. Resistor R25 is connected to the forty-fifth pin of analog front-end acquisition chip U8 through capacitors C25, C26, C39, and C69. Transient voltage suppressor TVS5 is grounded through capacitors C25 and C26.

[0017] Furthermore, the temperature acquisition module includes a thermistor NTC1, capacitors C57, C61, and C60, and a terminal J4. The twenty-third pin of the analog front-end acquisition chip U8 is connected to capacitor C57 and the thermistor NTC1, and the other end of capacitor C57 and the thermistor NTC1 is grounded.

[0018] The twenty-fourth pin of the analog front-end acquisition chip U8 is connected to the capacitor C61 and the first pin of the terminal J4. The other end of the capacitor C61 is connected to the second pin of the terminal J4. The twenty-fifth pin of the analog front-end acquisition chip U8 is connected to the capacitor C60 and the third pin of the terminal J4. The other end of the capacitor C60 is connected to the fourth pin of the terminal J4. Two NTC harnesses are externally connected to the terminal J4. The thermistor NTC1 is used to acquire the temperature of the MOSFET. The external NTC harnesses are used to acquire the temperature of the battery cell. The twenty-second pin of the analog front-end acquisition chip U8 is connected to the resistor R190. The eighteenth pin of the analog front-end acquisition chip U8 is connected to the resistor R203. The nineteenth pin of the analog front-end acquisition chip U8 is connected to the resistor R202. The twentieth pin of the analog front-end acquisition chip U8 is connected to the resistor R201.

[0019] Furthermore, the current acquisition module includes current detection resistors RS1 and RS2, capacitors C75, C76, and C77, resistors R180 and R181. The seventeenth pin of the analog front-end acquisition chip U8, the current monitoring input terminal, is connected to capacitors C75, R180, and C76. The sixteenth pin (pin 16) of the analog front-end acquisition chip U8 is connected to capacitors C75, R181, and C77. The other ends of capacitors C76 and C77 are grounded. The other end of resistor R180 is connected to current detection resistors RS1 and RS2. The other end of resistor R181 is connected to the other ends of current detection resistors RS1 and RS2.

[0020] Furthermore, the charging and discharging module includes MOSFETs QM2, QM8, Q24, and Q31, resistor R176, diode D20, capacitor C69, transient voltage suppressor TVS7, and Zener diode DZ5. The 44th pin CP1 of the analog front-end acquisition chip U8 is connected to capacitor C69, and the other end of capacitor C69 is connected to the positive terminal BAT+ of the battery cluster. The 42nd pin CHG of the analog front-end acquisition chip U8 is connected to resistor R176, and the other end of resistor R176 is connected to the anode of diode D20, the base of transistor Q26, and resistor R136. The other end of 136 is connected to the collector of transistor Q26, resistors R133 and R115, transient voltage suppressor TVS7, Zener diode DZ5, resistor R130, and the source of MOSFET QM2. The emitter of transistor Q26 is connected to the base of transistor Q24. The cathode of diode D20 is connected to the emitter of transistor Q24, resistor R155, transient voltage suppressor TVS7, Zener diode DZ5, and resistor R119. The other end of resistor R119 is connected to the gate of MOSFET QM2. Resistor R130 is connected to capacitor C63, and the other end of capacitor C63 is connected to the drain of MOSFET QM2.

[0021] Pin 41 (DSG) of the analog front-end acquisition chip U8 is connected to resistor R178. The other end of resistor R178 is connected to the anode of diode D21, the base of transistor Q32, and resistor R164. The other end of resistor R164 is connected to the collector of transistor Q32, resistors R162 and R163, transient voltage suppressor TVS12, Zener diode DZ7, capacitor C68, and the source of MOSFET QM8. The emitter of transistor Q32 is connected to the base of transistor Q31. The cathode of diode D21 is connected to the emitter of transistor Q31, resistor R163, transient voltage suppressor TVS12, Zener diode DZ7, and resistor R152. The other end of resistor R152 is connected to the gate of MOSFET QM8. Capacitor C68 is connected to resistor R147. The other end of resistor R147 is connected to capacitor C63, the drain of MOSFET QM8, and the drain of MOSFET QM2.

[0022] Furthermore, the pre-charge / discharge module includes MOSFET Q5, MOSFET Q16, diode DZ8, resistors R96 and R33, capacitors C29 and C27. Pin 39 (PDSG) of the analog front-end acquisition chip U8 is connected to resistor R96. The other end of resistor R96 is connected to the anode of diode DZ8, resistor R33, and the gate of MOSFET Q16. The drain of MOSFET Q16 is connected to resistor R77. The other end of resistor R77 is connected to capacitor C29. Pin 40 (PCHG) of the analog front-end acquisition chip U8 is connected to resistor R34. The other end of resistor R34 is connected to the anode of diode DZ4, resistor R32, and the gate of MOSFET Q5. The drain of MOSFET Q5 is connected to capacitor C27 via resistor R30. The cathode of diode DZ4 is connected to the cathode of diode DZ8, resistors R32 and R33, the source of MOSFET Q5, and the source of MOSFET Q16.

[0023] Furthermore, the twentieth pin of the main control chip MCU U1 is connected to the thirty-third pin of the analog front-end acquisition chip U8 through resistor R90, the twenty-first pin of the main control chip MCU U1 is connected to the thirty-fourth pin of the analog front-end acquisition chip U8 through resistor R87, the twenty-second pin of the main control chip MCU U1 is connected to the thirty-second pin of the analog front-end acquisition chip U8 through resistor R93, and the twenty-third pin of the main control chip MCU U1 is connected to the thirty-fifth pin of the analog front-end acquisition chip U8 through resistor R82.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. This utility model utilizes a single chip to perform sampling, equalization, single-cell overvoltage protection, single-cell undervoltage protection, total voltage overvoltage protection, and total voltage undervoltage protection for 7-16 series batteries. It can also achieve up to 8-channel temperature detection to realize over-temperature and low-temperature protection, providing better monitoring and protection of circuit and cell temperatures. In addition, the current sampling function can realize charging overcurrent protection and discharging overcurrent protection. Furthermore, it is equipped with pre-charge function, pre-discharge function, load detection, charger detection, and charge / discharge control functions.

[0026] 2. Moreover, the main control chip MCU U1 serves as the central control of the entire system, allocating resources and detecting data for system modules. The voltage acquisition and equalization module and the analog front-end acquisition chip work together to complete the real-time acquisition and equalization of the voltage of each battery string. All sampled and processed data are transmitted to the main control chip MCU U1 via SPI communication. The main control chip MCU U1 processes the signals to realize the functions of single cell overvoltage protection, single cell undervoltage protection, total voltage overvoltage protection, and total voltage undervoltage protection.

[0027] 3. The analog front-end acquisition chip U8 samples the temperature and transmits all sampled and processed data to the main control chip MCU U1 via SPI communication. The main control chip MCU U1 processes the signal to realize the functions of high temperature protection during charging, low temperature protection during charging, high temperature protection during discharging, and low temperature protection during discharging.

[0028] 4. The analog front-end acquisition chip U8 sends pre-charge and pre-discharge signals to control the pre-charge and pre-discharge MOS to turn on or off, thereby realizing the pre-charge and pre-discharge control of the battery. The charger detection module determines whether the charger is connected by detecting the positive voltage of the charger and transmits the sampled and processed data to the main control chip MCU U1. After processing the signal, the main control chip MCU U1 controls the charging MOS to turn on or off. Subsequently, it detects the positive voltage of the load to determine whether the load is connected and transmits the sampled and processed data to the main control chip MCU U1. After processing the signal, the main control chip MCU U1 controls the discharging MOS to turn on or off. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the system principle of this utility model;

[0030] Figure 2 This is a schematic diagram of the circuit structure of this utility model;

[0031] Figure 3 This is a schematic diagram of the pre-charge and discharge module circuit structure of this utility model;

[0032] Figure 4 This is a schematic diagram of the main control chip MCU U1 of this utility model;

[0033] Figure 5 This is a schematic diagram of the circuit structure of the charging and discharging module of this utility model. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0035] Please see Figures 1-5This utility model provides a technical solution: a lithium battery management system supporting high-side direct drive, comprising: a main control chip MCU U1, an analog front-end acquisition chip U8, a voltage acquisition and equalization module, a temperature acquisition module, a current acquisition module, a charge and discharge module, and a pre-charge and discharge module. The main control chip MCU U1 and the analog front-end acquisition chip U8, the voltage acquisition and equalization module, the temperature acquisition module, the current acquisition module, the charge and discharge module, and the pre-charge and discharge module are connected and interact via the SPI communication protocol.

[0036] The main control chip MCU U1 serves as the central control of the entire system, used for system module resource allocation and data detection.

[0037] The analog front-end acquisition chip U8 is responsible for acquiring the battery's voltage, temperature, and current parameters, as well as processing pre-charge and discharge signals. The analog front-end acquisition chip U8 transmits the collected information to the main control chip MCUU1 and controls the execution of processes such as equalization and pre-charge and discharge according to the instructions of MCUU1.

[0038] The voltage acquisition and equalization module is configured as a first voltage acquisition and equalization module and a second voltage acquisition and equalization module. The first voltage acquisition and equalization module and the second voltage acquisition and equalization module, together with the analog front-end acquisition chip U8, complete the real-time acquisition and equalization of the voltage of each battery string in the battery cluster; to ensure that the individual batteries in the battery pack maintain a consistent working state and avoid safety hazards caused by imbalance.

[0039] The analog front-end acquisition chip U8 implements 8-channel temperature sampling and processing, realizing high-temperature protection during charging, low-temperature protection during charging, high-temperature protection during discharging, and low-temperature protection during discharging; preventing overheating or low-temperature environments from affecting battery performance. Temperature information is also sent to the MCU for processing to implement the corresponding protection functions.

[0040] The current acquisition module compares the voltage across the analog front-end acquisition chip U8 with the internal current of the chip, samples the current, and implements overcurrent protection to ensure that no overcurrent occurs. Once an anomaly is detected, it immediately reports to the MCU so that appropriate measures can be taken.

[0041] The charging and discharging module controls the on / off state of the charging and discharging MOSFETs according to the MCU's instructions, ensuring that the battery charges and discharges under safe conditions. It can also quickly respond to emergencies by cutting off the circuit to protect the battery from damage.

[0042] The pre-charge / discharge module is used to realize the pre-charge / discharge function of the battery, which is crucial for extending battery life.

[0043] This system utilizes a single chip to perform sampling, balancing, individual cell overvoltage protection, individual cell undervoltage protection, total voltage overvoltage protection, and total voltage undervoltage protection for 7-16 battery cells. It can also achieve up to 8-channel temperature detection for over- and under-temperature protection, providing better monitoring and protection of circuit and cell temperatures. Furthermore, the current sampling function enables charging overcurrent protection and discharging overcurrent protection, and it also includes pre-charging, pre-discharging, load detection, charger detection, and charge / discharge control functions. The main control chip, MCU U1, acts as the central controller of the entire system, allocating resources and monitoring data for system modules. The voltage acquisition and balancing module and the analog front-end acquisition chip collaborate to collect and balance the voltage of each battery cell in real time. All sampled and processed data is transmitted to the main control chip, MCU U1, via SPI communication. MCU U1 processes the signals to implement individual cell overvoltage protection, individual cell undervoltage protection, total voltage overvoltage protection, and total voltage undervoltage protection. The analog front-end acquisition chip U8 samples the temperature and transmits all sampled and processed data to the main control chip, MCU U1, via SPI communication. U1 processes the signals to implement high-temperature protection during charging, low-temperature protection during charging, high-temperature protection during discharging, and low-temperature protection during discharging. The analog front-end acquisition chip U8 sends pre-charge and pre-discharge signals to control the pre-charge and pre-discharge MOS transistors to turn on or off, thereby controlling the pre-charge and discharge of the battery. The charger detection module determines whether the charger is connected by detecting the positive voltage of the charger and transmits the sampled and processed data to the main control chip MCU U1. After processing the signal, the main control chip MCU U1 controls the charging MOS transistor to turn on or off. Subsequently, it detects the positive voltage of the load to determine whether the load is connected and transmits the sampled and processed data to the main control chip MCU U1. After processing the signal, the main control chip MCU U1 controls the discharging MOS transistor to turn on or off.

[0044] Please see Figures 1-5 The voltage acquisition and equalization module includes terminal J5, terminal J8, transistor Q34, transistor Q35, resistor R92, resistor R167, resistor R170, resistor R171 and capacitor C72. The first to fifteenth pins of terminal J5 are respectively connected to the positive and negative terminals of multiple battery strings in the battery cluster and the connection.

[0045] The sixth pin of terminal J8 is connected to the positive terminal BAT+ of the battery cluster, along with the positive terminal of the fifteenth battery string, the first pin of terminal J8, the second pin of terminal J8, the third pin of terminal J8, and the fourth pin of terminal J8.

[0046] The fifteenth pin of terminal J5 is connected to the emitter of transistor Q35 and resistor R171. The fourteenth pin of terminal J5 is connected to resistor R92, transistor Q34 and resistor R167. The other end of resistor R167 is connected to capacitor C72 and the thirteenth pin of analog front-end acquisition chip U8. The other end of resistor R92 is connected to the collector of transistor Q35. The base of transistor Q35 is connected to resistor R170. The other end of resistor R170 is connected to resistor R171, capacitor C72 and the fourteenth pin of analog front-end acquisition chip U8. This circuit completes the voltage acquisition of the first string of batteries in the battery cluster. When pin 14 of U8 controls Q35 to conduct, the equalization function of the first string of batteries is realized.

[0047] The fifth pin of terminal J8 is connected to resistor R28. The other end of resistor R28 is connected to the positive terminal BAT+ of the battery pack through fuse F2. Fuse F2 and resistor R28 provide overcurrent protection. The other end of fuse F2 is connected to the anode of diode D11. The cathode of diode D11 is connected to transient voltage suppressor TVS5 and resistor R25. Resistor R25 is connected to the forty-fifth pin of analog front-end acquisition chip U8 through capacitors C25, C26, C39, and C69. Transient voltage suppressor TVS5 is grounded through capacitors C25 and C26.

[0048] Among them, diode D11 serves to prevent reverse connection, transient voltage suppressor TVS5 serves to eliminate voltage spikes, resistor R25 and capacitor C26 form an RC filter, capacitors C39 and C69 adjust the turn-off time of MOSFETs, and pin 44 of analog front-end acquisition chip U8 is the charge pump CP1 pin, which generates VBAT+11.5V voltage to drive the gate of the high-side MOSFET.

[0049] Terminals J5 and J8 are used to connect the individual battery cells in the battery cluster, ensuring that the voltage signal is correctly introduced into the acquisition circuit. Transistors Q34 and Q35, as switching elements, control the current path in the circuit, which is crucial for achieving the equalization function. For example, when the voltage of a battery string is too high, the corresponding MOSFET can be controlled to shunt the current, achieving the equalization purpose. Resistors R92, R167, R170, and R171 are used to limit the current magnitude or divide the voltage, ensuring the stability and safety of the circuit operation. Simultaneously, the resistors also participate in the voltage detection loop, while capacitor C72 is used to filter and smooth the voltage signal, eliminating noise interference and ensuring the accuracy of voltage measurement. Furthermore, multiple components, along with the analog front-end acquisition chip U8, are responsible for processing data from the voltage acquisition and equalization module and performing necessary signal processing tasks, such as voltage sampling and equalization control, for data conversion, processing, and transmission. These components are interconnected through circuitry to form a complete voltage acquisition and equalization system. For example, the voltage acquisition and equalization module connects each battery string in the battery pack to the circuit via terminals, using transistors and resistor networks to acquire and equalize voltage, which is then processed and analyzed by the analog front-end acquisition chip U8. This collaborative approach not only ensures accurate voltage information acquisition but also enables effective management of voltage differences within the battery pack, guaranteeing its safe and efficient operation.

[0050] Please see Figures 1-5 The temperature acquisition module includes a thermistor NTC1, a capacitor C57, a capacitor C61, a capacitor C60, and a terminal J4. The twenty-third pin of the analog front-end acquisition chip U8 is connected to the capacitor C57 and the thermistor NTC1, and the other end of the capacitor C57 and the thermistor NTC1 is grounded.

[0051] The 24th pin of the analog front-end acquisition chip U8 is connected to capacitor C61 and the first pin of terminal J4. The other end of capacitor C61 is connected to the second pin of terminal J4. The 25th pin of the analog front-end acquisition chip U8 is connected to capacitor C60 and the third pin of terminal J4. The other end of capacitor C60 is connected to the fourth pin of terminal J4. Two NTC harnesses are externally connected to terminal J4. The thermistor NTC1 is used to acquire the temperature of the MOSFET, and the external NTC harnesses are used to acquire the temperature of the battery cell. The 22nd pin of the analog front-end acquisition chip U8 is connected to resistor R190, the 18th pin of the analog front-end acquisition chip U8 is connected to resistor R203, the 19th pin of the analog front-end acquisition chip U8 is connected to resistor R202, the 20th pin of the analog front-end acquisition chip U8 is connected to resistor R201, and the 21st pin of the analog front-end acquisition chip U8 is connected to ground through resistors R200, R190, R200, R201, R202, and R203. Unused temperature acquisition pull-down processing.

[0052] The analog front-end acquisition chip U8 serves as the core processing unit, responsible for receiving and analyzing temperature signals from the thermistor NTC1. It enables up to eight temperature sampling channels, allowing simultaneous temperature monitoring at multiple locations. The thermistor NTC1 directly measures temperature changes; its resistance decreases as temperature increases. Connected to key components requiring temperature monitoring, such as MOSFETs and battery cells, the thermistor converts temperature information into electrical signals that are transmitted to the analog front-end acquisition chip U8. Capacitors C57, C61, and C60 filter and smooth the temperature signal, eliminating noise interference and ensuring accurate temperature measurements. These capacitors are connected in parallel with the thermistor NTC1 to help stabilize the voltage signal. Terminal J4 connects to external NTC thermistors or other types of temperature sensors, allowing the temperature acquisition module to be flexibly positioned within the battery pack to obtain more comprehensive temperature data.

[0053] Please see Figures 1-5The current acquisition module includes current sensing resistors RS1 and RS2, capacitors C75, C76, and C77, resistors R180 and R181. The seventeenth pin of the analog front-end acquisition chip U8, the current monitoring input terminal, is connected to capacitors C75, R180, and C76. The sixteenth pin (pin 16) of the analog front-end acquisition chip U8 is connected to capacitors C75, R181, and C77. The other ends of capacitors C76 and C77 are grounded. The other end of resistor R180 is connected to current sensing resistors RS1 and RS2. The other end of resistor R181 is connected to the other ends of current sensing resistors RS1 and RS2. The analog front-end acquisition chip U8 acquires the voltage across RS1 and RS2 and compares this voltage internally to sample the current, thereby monitoring the current and implementing overcurrent protection.

[0054] When current flows through current sensing resistors RS1 and RS2, a small voltage drop is generated across these two resistors. Pin 17 SRN of the analog front-end acquisition chip U8 is connected to one end of capacitor C75, one end of resistor R180, and one end of current sensing resistor RS1; while pin 16 SRP of the analog front-end acquisition chip U8 is connected to the other end of capacitor C75, one end of resistor R181, and one end of current sensing resistor RS2. The voltage difference between current sensing resistors RS1 and RS2 reflects the actual current flowing through the circuit.

[0055] The analog front-end acquisition chip U8 compares the voltage difference between SRN and SRP and converts it into a corresponding current value. The processed current data is then transmitted to the main control chip MCU U1 via SPI communication. Based on the current data obtained from the analog front-end acquisition chip U8, the main control chip MCU U1 can decide whether to take protective measures, such as cutting off the charging or discharging path, according to the preset safety threshold, to avoid safety risks caused by overcurrent.

[0056] Please see Figures 1-5The charging / discharging module includes MOSFETs QM2, QM8, Q24, and Q31, resistor R176, diode D20, capacitor C69, transient voltage suppressor TVS7, and Zener diode DZ5. The 44th pin (CP1) of the analog front-end acquisition chip U8 is connected to capacitor C69, with the other end of C69 connected to the positive terminal BAT+ of the battery cluster. After the charge pump is activated, the voltage at pin CP1 of the analog front-end acquisition chip U8 will increase to approximately VBAT+11V. The 42nd pin (CHG) of the analog front-end acquisition chip U8 is connected to resistor R176, with the other end of resistor R176 connected to the anode and crystal of diode D20. The base of transistor Q26 is connected to resistor R136. The other end of resistor R136 is connected to the collector of transistor Q26, resistors R133 and R115, transient voltage suppressor TVS7, Zener diode DZ5, resistor R130, and the source of MOSFET QM2. The emitter of transistor Q26 is connected to the base of transistor Q24. The cathode of diode D20 is connected to the emitter of transistor Q24, resistor R155, transient voltage suppressor TVS7, Zener diode DZ5, and resistor R119. The other end of resistor R119 is connected to the gate of MOSFET QM2. Resistor R130 is connected to capacitor C63, and the other end of capacitor C63 is connected to the drain of MOSFET QM2.

[0057] Pin 41 (DSG) of the analog front-end acquisition chip U8 is connected to resistor R178. The other end of resistor R178 is connected to the anode of diode D21, the base of transistor Q32, and resistor R164. The other end of resistor R164 is connected to the collector of transistor Q32, resistors R162 and R163, transient voltage suppressor TVS12, Zener diode DZ7, capacitor C68, and the source of MOSFET QM8. The emitter of transistor Q32 is connected to the base of transistor Q31, and the cathode of diode D21 is connected to the emitter of transistor Q31. The emitter, resistor R163, transient voltage suppressor TVS12, Zener diode DZ7, and resistor R152 are connected together. The other end of resistor R152 is connected to the gate of MOSFET QM8. Capacitor C68 is connected to resistor R147. The other end of resistor R147 is connected to capacitor C63, the drain of MOSFET QM8, and the drain of MOSFET QM2. This circuit controls the conduction and turn-off of the charging and discharging MOSFETs, protects the MOSFETs, and accelerates the turn-off of the MOSFETs. Diode D13 and capacitor C54 are connected between charger interfaces CON1 and CON2 to provide freewheeling current.

[0058] During charging control;

[0059] • Pin CP1 of the analog front-end acquisition chip U8 is connected to the positive terminal BAT+ of the battery cluster through capacitor C69. When the charge pump is started, the voltage on this pin will rise to approximately 11V (VBAT+) to drive the gate of the high-side MOSFET. Pin CHG of the analog front-end acquisition chip U8 is connected to the anode of diode D20, the base of transistor Q26, and resistor R136 through resistor R176. This part of the circuit is responsible for sending a charging control signal to MOSFET QM2 to determine when to turn on or off the charging path. When charging is required, the analog front-end acquisition chip U8 will send a control signal, which, after being adjusted by relevant resistors and diodes, reaches the gate of MOSFET QM2, turning on MOSFET QM2 and allowing charging current to flow into the battery.

[0060] During discharge control:

[0061] Pin 41, DSG, of the analog front-end acquisition chip U8 is connected to the anode of diode D21, the base of transistor Q32, and resistor R164 via resistor R178. This part of the circuit is used to control the switching state of MOSFET QM8 to manage the discharge path. When discharge is required, the analog front-end acquisition chip U8 will send a corresponding control signal, which, after being adjusted by the relevant resistors and diodes, acts on the gate of MOSFET QM8, turning on MOSFET QM8 and allowing the discharge current to flow out of the battery.

[0062] Please see Figures 1-5 The pre-charge / discharge module includes MOSFET Q5, MOSFET Q16, diode DZ8, resistors R96 and R33, capacitors C29 and C27. Pin 39 (PDSG) of the analog front-end acquisition chip U8 is connected to resistor R96. The other end of resistor R96 is connected to the anode of diode DZ8, resistor R33, and the gate of MOSFET Q16. The drain of MOSFET Q16 is connected to resistor R77. The other end of resistor R77 is connected to capacitor C29. Pin 40 (PCHG) of the analog front-end acquisition chip U8 is connected to resistor R34. The other end of resistor R34 is connected to the anode of diode DZ4, resistor R32, and the gate of MOSFET Q5. The drain of MOSFET Q5 is connected to capacitor C27 via resistor R30. The cathode of diode DZ4 is connected to the cathode of diode DZ8, resistors R32 and R33, the source of MOSFET Q5, and the source of MOSFET Q16. The 39th and 40th pins of the analog front-end acquisition chip U8 control the on and off states of MOSFETs Q5 and Q16 to achieve the pre-charge and discharge function of the battery.

[0063] The pre-charging path includes:

[0064] Pin 40, PCHG of the analog front-end acquisition chip U8, is connected to the anode of Zener diode DZ4, resistor R32, and the gate of MOSFET Q5 via resistor R34. This part of the circuit is used to send pre-charge commands. When the battery needs to be pre-charged, pin 40, PCHG of the analog front-end acquisition chip U8 sends a control signal. After being adjusted by resistor R34, Zener diode DZ4, resistors R32 and R33, the signal reaches the gate of MOSFET Q5. If the conditions are met, MOSFET Q5 is turned on, allowing a small current to pass through, thus achieving pre-charging. The drain of MOSFET Q5 is connected to resistor R30, and the other end of resistor R30 is connected to capacitor C27. This helps to adjust the operating characteristics of the MOSFET and ensure a smooth pre-charging process.

[0065] Pre-discharge path:

[0066] Pin 39, PDSG, of the analog front-end acquisition chip U8 is connected to the anode of Zener diode DZ8, resistor R33, and the gate of MOSFET Q16 via resistor R96. This part of the circuit is used to send pre-discharge commands. When the battery needs to be pre-discharged, the analog front-end acquisition chip U8 sends a corresponding control signal through its pin 39, PDSG. After being adjusted by resistor R96, Zener diode DZ8, and resistor R33, the signal acts on the gate of MOSFET Q16. When MOSFET Q16 is turned on, a small current discharge of the battery can be achieved, completing the pre-discharge process. The drain of MOSFET Q16 is connected to resistor R77, and the other end of resistor R77 is connected to capacitor C29. This helps to adjust the operating characteristics of the MOSFET and ensure a smooth pre-discharge process.

[0067] Please see Figures 1-5 The 20th pin of the main control chip MCU U1 is connected to the 33rd pin of the analog front-end acquisition chip U8 through resistor R90. The 21st pin of the main control chip MCU U1 is connected to the 34th pin of the analog front-end acquisition chip U8 through resistor R87. The 22nd pin of the main control chip MCU U1 is connected to the 32nd pin of the analog front-end acquisition chip U8 through resistor R93. The 23rd pin of the main control chip MCU U1 is connected to the 35th pin of the analog front-end acquisition chip U8 through resistor R82. This communication is via SPI communication, consisting of SDI, SDO, SCK, and CS signals. The analog front-end acquisition chip U8 and the main control chip MCU U1 complete the mutual signal transmission through this circuit.

[0068] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A lithium battery management system supporting high-side direct drive, characterized in that: include: The system includes a main control chip MCU U1, an analog front-end acquisition chip U8, a voltage acquisition and equalization module, a temperature acquisition module, a current acquisition module, a charge and discharge module, and a pre-charge and discharge module. The main control chip MCU U1 and the analog front-end acquisition chip U8, voltage acquisition and equalization module, temperature acquisition module, current acquisition module, charge and discharge module, and pre-charge and discharge module are connected and interact via the SPI communication protocol. The main control chip MCU U1 is used for system module resource allocation and data detection; The analog front-end acquisition chip U8 is responsible for acquiring the battery's voltage, temperature, and current parameters, as well as processing pre-charge and discharge signals. The voltage acquisition and equalization module is configured as a first voltage acquisition and equalization module and a second voltage acquisition and equalization module. The first voltage acquisition and equalization module and the second voltage acquisition and equalization module, together with the analog front-end acquisition chip U8, complete the real-time acquisition and equalization of the voltage of each battery string in the battery cluster. The analog front-end acquisition chip U8 realizes 8-channel temperature sampling and processing, and realizes the functions of high temperature protection during charging, low temperature protection during charging, high temperature protection during discharging, and low temperature protection during discharging. The current acquisition module is used to compare the voltage across the analog front-end acquisition chip U8 with the internal current of the analog front-end acquisition chip U8, sample the current, and realize the overcurrent protection function. The charging and discharging module controls the on / off state of the charging and discharging MOSFETs according to the MCU's instructions, ensuring that the battery charges and discharges under safe conditions. It can also quickly respond to emergencies by cutting off the circuit to protect the battery from damage. The pre-charge / discharge module is used to realize the pre-charge / discharge function of the battery.

2. A lithium battery management system supporting high-side direct drive according to claim 1, characterized in that: The voltage acquisition and equalization module includes terminal J5, terminal J8, transistor Q34, transistor Q35, resistor R92, resistor R167, resistor R170, resistor R171 and capacitor C72. The first to fifteenth pins of terminal J5 are respectively connected to the positive and negative terminals of multiple battery strings in the battery cluster and the connection. The sixth pin of terminal J8 is connected to the positive terminal BAT+ of the battery cluster, along with the positive terminal of the fifteenth battery string, the first pin of terminal J8, the second pin of terminal J8, the third pin of terminal J8, and the fourth pin of terminal J8. The fifteenth pin of terminal J5 is connected to the emitter of transistor Q35 and resistor R171. The fourteenth pin of terminal J5 is connected to resistor R92, transistor Q34 and resistor R167. The other end of resistor R167 is connected to capacitor C72 and the thirteenth pin of analog front-end acquisition chip U8. The other end of resistor R92 is connected to the collector of transistor Q35. The base of transistor Q35 is connected to resistor R170. The other end of resistor R170 is connected to resistor R171, capacitor C72 and the fourteenth pin of analog front-end acquisition chip U8. The fifth pin of terminal J8 is connected to resistor R28. The other end of resistor R28 is connected to the positive terminal BAT+ of the battery cluster through fuse F2. The other end of fuse F2 is connected to the anode of diode D11. The cathode of diode D11 is connected to transient voltage suppressor TVS5 and resistor R25. Resistor R25 is connected to the forty-fifth pin of analog front-end acquisition chip U8 through capacitors C25, C26, C39, and C69. Transient voltage suppressor TVS5 is grounded through capacitors C25 and C26.

3. A lithium battery management system supporting high-side direct drive according to claim 2, characterized in that: The temperature acquisition module includes a thermistor NTC1, a capacitor C57, a capacitor C61, a capacitor C60, and a terminal J4. The twenty-third pin of the analog front-end acquisition chip U8 is connected to the capacitor C57 and the thermistor NTC1, and the other end of the capacitor C57 and the thermistor NTC1 is grounded. The 24th pin of the analog front-end acquisition chip U8 is connected to the capacitor C61 and the first pin of the terminal J4. The other end of the capacitor C61 is connected to the second pin of the terminal J4. The 25th pin of the analog front-end acquisition chip U8 is connected to the capacitor C60 and the third pin of the terminal J4. The other end of the capacitor C60 is connected to the fourth pin of the terminal J4. Two NTC harnesses are externally connected to the terminal J4. The thermistor NTC1 is used to acquire the temperature of the MOSFET, and the external NTC harnesses are used to acquire the temperature of the battery cell. The 22nd pin of the analog front-end acquisition chip U8 is connected to the resistor R190. The 18th pin of the analog front-end acquisition chip U8 is connected to the resistor R203. The 19th pin of the analog front-end acquisition chip U8 is connected to the resistor R202. The 20th pin of the analog front-end acquisition chip U8 is connected to the resistor R201.

4. A lithium battery management system supporting high-side direct drive according to claim 3, characterized in that: The current acquisition module includes current detection resistors RS1 and RS2, capacitors C75, C76, and C77, resistors R180 and R181. The seventeenth pin of the analog front-end acquisition chip U8, the current monitoring input terminal, is connected to capacitors C75, R180, and C76. The sixteenth pin (pin 16) of the analog front-end acquisition chip U8 is connected to capacitors C75, R181, and C77. The other ends of capacitors C76 and C77 are grounded. The other end of resistor R180 is connected to current detection resistors RS1 and RS2. The other end of resistor R181 is connected to the other ends of current detection resistors RS1 and RS2.

5. A lithium battery management system supporting high-side direct drive according to claim 4, characterized in that: The charging / discharging module includes MOSFETs QM2, QM8, Q24, and Q31, resistor R176, diode D20, capacitor C69, transient voltage suppressor TVS7, and Zener diode DZ5. The 44th pin (CP1) of the analog front-end acquisition chip U8 is connected to capacitor C69, with the other end of C69 connected to the positive terminal (BAT+) of the battery cluster. The 42nd pin (CHG) of the analog front-end acquisition chip U8 is connected to resistor R176, with the other end of R176 connected to the anode of diode D20, the base of transistor Q26, and resistor R136. The other end is connected to the collector of transistor Q26, resistors R133 and R115, transient voltage suppressor TVS7, Zener diode DZ5, resistor R130, and the source of MOSFET QM2. The emitter of transistor Q26 is connected to the base of transistor Q24. The cathode of diode D20 is connected to the emitter of transistor Q24, resistor R155, transient voltage suppressor TVS7, Zener diode DZ5, and resistor R119. The other end of resistor R119 is connected to the gate of MOSFET QM2. Resistor R130 is connected to capacitor C63, and the other end of capacitor C63 is connected to the drain of MOSFET QM2. Pin 41 (DSG) of the analog front-end acquisition chip U8 is connected to resistor R178. The other end of resistor R178 is connected to the anode of diode D21, the base of transistor Q32, and resistor R164. The other end of resistor R164 is connected to the collector of transistor Q32, resistors R162 and R163, transient voltage suppressor TVS12, Zener diode DZ7, capacitor C68, and the source of MOSFET QM8. The emitter of transistor Q32 is connected to the base of transistor Q31. The cathode of diode D21 is connected to the emitter of transistor Q31, resistor R163, transient voltage suppressor TVS12, Zener diode DZ7, and resistor R152. The other end of resistor R152 is connected to the gate of MOSFET QM8. Capacitor C68 is connected to resistor R147. The other end of resistor R147 is connected to capacitor C63, the drain of MOSFET QM8, and the drain of MOSFET QM2.

6. A lithium battery management system supporting high-side direct drive according to claim 5, characterized in that: The pre-charge / discharge module includes MOSFET Q5, MOSFET Q16, diode DZ8, resistors R96 and R33, capacitors C29 and C27. Pin 39 (PDSG) of the analog front-end acquisition chip U8 is connected to resistor R96. The other end of resistor R96 is connected to the anode of diode DZ8, resistor R33, and the gate of MOSFET Q16. The drain of MOSFET Q16 is connected to resistor R77. The other end of resistor R77 is connected to capacitor C29. Pin 40 (PCHG) of the analog front-end acquisition chip U8 is connected to resistor R34. The other end of resistor R34 is connected to the anode of diode DZ4, resistor R32, and the gate of MOSFET Q5. The drain of MOSFET Q5 is connected to capacitor C27 via resistor R30. The cathode of diode DZ4 is connected to the cathode of diode DZ8, resistors R32 and R33, the source of MOSFET Q5, and the source of MOSFET Q16.

7. A lithium battery management system supporting high-side direct drive according to claim 6, characterized in that: The twentieth pin of the main control chip MCU U1 is connected to the thirty-third pin of the analog front-end acquisition chip U8 through resistor R90. The twenty-first pin of the main control chip MCU U1 is connected to the thirty-fourth pin of the analog front-end acquisition chip U8 through resistor R87. The twenty-second pin of the main control chip MCU U1 is connected to the thirty-second pin of the analog front-end acquisition chip U8 through resistor R93. The twenty-third pin of the main control chip MCU U1 is connected to the thirty-fifth pin of the analog front-end acquisition chip U8 through resistor R82.

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