Intelligent lithium ion / sodium ion battery pack BMS management system
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENZHEN HUAYAN JINGCHUANG TECH CO LTD
- Filing Date
- 2025-04-08
- Publication Date
- 2026-05-22
Smart Images
Figure CN224267054U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of battery pack BMS management system, and in particular to an intelligent lithium-ion / sodium-ion battery pack BMS management system. Background Technology
[0002] The existing high-power battery pack BMS technology suffers from problems such as high integration and algorithm accuracy, high hardware requirements, high development costs, large energy loss, low efficiency, few communication protection measures, high integration and complexity, poor compatibility with different types of battery management, high maintenance and upgrade difficulty, inaccurate data measurement, few communication interfaces, and low integration of various functions such as automatic fault alarm.
[0003] 1. Similar products on the market fall into two categories:
[0004] 1) Relay solution:
[0005] ① In battery packs with a working voltage of less than 100V, the relative capacity of the battery pack is not large, and the relay-type management system is composed of multiple circuit subsystems. Therefore, the current consumption is too large when the device is in a static state. Long-term use and storage will result in excessive battery capacity measurement error. During the use of the equipment, due to inaccurate power measurement, there is a safety risk of sudden power failure during use. This is especially dangerous for vehicle products, where sudden power failure during driving is particularly dangerous.
[0006] ② The relay solution is composed of multiple subsystem circuit modules, so it has a complex structure, complicated installation, many wiring harnesses, and high cost.
[0007] ③ The current sampling resolution of the relay solution is not high across the entire current range, and small currents cannot be measured. Therefore, the small current consumption generated by the equipment when it is not in use or is static cannot be effectively measured, resulting in a large SOC error and incorrect power display.
[0008] ④ The relay solution does not have short-circuit protection. Therefore, when a short circuit occurs in the equipment, the battery pack will blow the fuse and lose its function, requiring it to be returned to the factory for repair.
[0009] ⑤ Due to the large cumulative error in SOC metering, the equipment is prone to sudden premature power outages during operation, posing a safety hazard.
[0010] ⑥ The mechanical structure of a relay will wear down over time, which will affect its lifespan and reliability. Frequent operation will accelerate this wear, leading to a decline in relay performance or failure.
[0011] 2) Power MOSFET solution
[0012] ① In BMS management systems with voltages below 100V, products using MOSFET solutions typically employ consumer-grade AFE analog front-end chips for current acquisition. However, the sampling accuracy and voltage range of AFE analog chips are limited. This results in situations where small currents are acquired but large currents are not, and vice versa. Since the operating current of each device is relatively high, small currents cannot be acquired normally. After prolonged use, the system power consumption of the devices suffers from significant SOC calculation errors due to the inability to acquire data.
[0013] ② Since the current sampling rate of existing MOSFET solutions is generally greater than 100ms sampling time, in applications where the current fluctuation of power equipment is large, the coulomb accumulation error will be too large, which will lead to a large SOC metering error.
[0014] ③ The existing MOSFET solution has a limited number of BMS communication interfaces, making it inconvenient to expand various alarm tracking systems.
[0015] ④ Existing MOSFET solutions generally have a coulomb sampling accuracy greater than 1mA, but the sampling range is small and the cost is high. When accumulated over time, this leads to a large loss in the coulomb count, affecting the measurement and accuracy of the SOC.
[0016] 2. The cost is too high. The price of the lithium battery pack is too high, and it has no cost advantage in highly competitive markets such as direct application of lithium batteries or replacement of lead-acid batteries.
[0017] 3. Relay-type BMS protection systems do not have short-circuit protection. Once a short circuit occurs, they rely solely on external fuses for protection, posing a significant safety hazard.
[0018] 4. The relay contacts are mechanical, and high current can easily cause arcing. Over time, the contacts may fail to release or disconnect, resulting in the battery pack being depleted and rendered unusable.
[0019] 5. The number of communication ports is small, the number of peripherals that can be connected is too small, and the expandability is poor.
[0020] 6. Poor current sampling accuracy. The longer the usage time and the lower the temperature environment, the greater the power measurement error will be. Especially in special operation fields, the inaccurate measurement of battery power will pose a great production safety hazard.
[0021] 7. Low-voltage switch control has safety hazards due to high-level input, poor ESD protection at the switch terminals, and high voltage, high static electricity, and reverse polarity can easily damage the entire BMS system.
[0022] 8. The charging and discharging heating system on the BMS does not use PWM drive. When the heating element is activated, the surface temperature of the battery cell will be much higher than the internal temperature, which may damage the battery and pose a safety risk.
[0023] 9. The current sensing resistor of the BMS does not have a hardware auxiliary calibration circuit. When the resistance of the current sensing resistor changes due to heat, the current sampling accuracy will deteriorate accordingly. Utility Model Content
[0024] To address the problems existing in the prior art, this utility model provides an intelligent lithium-ion / sodium-ion battery pack BMS management system.
[0025] To achieve the above objectives, the technical solution of this utility model is as follows:
[0026] This utility model provides an intelligent lithium-ion / sodium-ion battery pack BMS management system, including:
[0027] Battery pack, power MOSFET circuit, AFE battery pack voltage / current acquisition circuit, pre-charge and discharge circuit, discharge circuit, main current sampling circuit, zero current calibration circuit, operational amplifier reference voltage source circuit, current and voltage sampling amplification circuit, central control circuit, charge and discharge current sampling circuit, power supply reference voltage source circuit, communication circuit;
[0028] The corresponding terminals of the central control circuit are electrically connected to the corresponding terminals of the AFE battery pack voltage / current acquisition circuit, power MOSFET circuit, current and voltage sampling amplification circuit, pre-charge and discharge circuit, discharge circuit, charge and discharge current sampling circuit, power reference voltage source circuit, and communication isolation module, respectively.
[0029] The positive terminal of the battery pack is electrically connected to the corresponding terminals of the power MOSFET circuit, the AFE battery pack voltage / current acquisition circuit, and the power reference voltage source circuit, respectively. The negative terminal of the battery pack is electrically connected to the corresponding terminals of the zero current calibration circuit, the AFE battery pack voltage / current acquisition circuit, the main current sampling circuit, the pre-charge-discharge circuit, and the slave discharge circuit, respectively.
[0030] The corresponding terminals of the AFE battery pack voltage / current acquisition circuit are also electrically connected to the corresponding terminals of the power supply reference voltage source circuit, the main current sampling circuit, the pre-charge and discharge circuit, the slave discharge circuit, and the operational amplifier reference voltage source circuit.
[0031] The corresponding terminals of the current and voltage sampling amplification circuit are also electrically connected to the corresponding terminals of the operational amplifier reference voltage source circuit, the main current sampling circuit, the pre-charge-discharge circuit, the slave discharge circuit, and the zero-current calibration circuit.
[0032] Preferably, the current and voltage sampling amplification circuit
[0033] It includes a battery pack charging current acquisition and amplification circuit and a battery pack discharging current acquisition and amplification circuit; the corresponding terminals of the battery pack charging current acquisition and amplification circuit and the battery pack discharging current acquisition and amplification circuit are electrically connected to the corresponding terminals of the central control circuit.
[0034] Preferably, the battery pack charging current acquisition and amplification circuit is used to acquire the current information of the battery pack during the charging process, and has three current levels: 60A-300A, 125mA-75A and 100mA-4A.
[0035] Preferably, the battery pack discharge current acquisition and amplification circuit is used to acquire the current information of the battery pack during the discharge process and can process a current range of 1mA to 3000A.
[0036] The battery pack discharge current acquisition and amplification circuit has five different sampling ranges: 260A-3000A, 60A-300A, 5A-75A, 1mA-1000mA, and 300mA.
[0037] Preferably, the intelligent lithium-ion / sodium-ion battery pack BMS management system further includes a Bluetooth and display module, a programmable voice module, a GPS / GSM tracking and transmission circuit, and the corresponding terminals of the central control circuit are electrically connected to the corresponding terminals of the Bluetooth and display module, the programmable voice module, and the GPS / GSM tracking and transmission circuit, respectively; the corresponding terminals of the GPS / GSM tracking and transmission circuit are also electrically connected to the corresponding terminals of the communication circuit, the charge and discharge current sampling circuit, the Bluetooth and display module, and the programmable voice module, respectively.
[0038] Preferably, the intelligent lithium-ion / sodium-ion battery pack BMS management system further includes a communication activation circuit and an AND gate communication wake-up circuit; the communication circuit is electrically connected to the corresponding terminals of the central control circuit in sequence via the AND gate communication wake-up circuit and the communication activation circuit.
[0039] Preferably, the intelligent lithium-ion / sodium-ion battery pack BMS management system further includes three NTCs, and the corresponding terminals of the central control circuit are electrically connected to the corresponding terminals of the AFE battery pack voltage / current acquisition circuit through the three NTCs.
[0040] Preferably, the power reference voltage source circuit includes a 12V power supply and a 5V power supply; the corresponding terminals of the 12V power supply are electrically connected to the positive terminal of the battery pack, the corresponding terminals of the GPS / GSM tracking and transmission circuit, and the corresponding terminals of the central control circuit, respectively; the corresponding terminals of the 5V power supply are electrically connected to the positive terminal of the battery pack, the central control circuit, the Bluetooth and display module, the programmable voice module, and the corresponding terminals of the GPS / GSM tracking and transmission circuit, respectively.
[0041] The technical solution of this utility model has the following beneficial effects:
[0042] 1. High-power MOSFETs are used to replace traditional relays. The operating current of all systems on the BMS board is collected with an accuracy better than 50uA. The charging and discharging main circuit current collection accuracy range is 1mA-3000A, ensuring the correct SOC of the battery pack during long-term storage or operation. This truly achieves the goal of not damaging the battery pack and ensuring the safety risk of power outages during normal battery pack operation, while also reducing product costs.
[0043] 2. A positive temperature coefficient PTC power resistor is used as the input resistor of the discharge circuit to isolate the discharge circuit from the coulomb counter circuit, reducing the possibility of further damage to components due to high power loss or energy discharge.
[0044] 3. Each power MOSFET uses an independent current sensing resistor. The voltage across each current sensing resistor is integrated and the average value is sent out as the I+ and I- signals. Since the average value of the integrating resistor is greater than that of the current sensing resistor, integration can be performed to reduce measurement error, and a portion of the current can be diverted in parallel to prevent excessive current from damaging internal components when connected to the detection circuit.
[0045] 4. Due to the use of power MOSFETs, parasitic capacitance exists within the MOSFETs. Since high-power output requires numerous power MOSFETs to control the circuit's switching, the resulting capacitance after parallel connection cannot be ignored. This parasitic capacitance slows down the switching on and off of the electronic switch. Currently, there are few temperature sampling ports, leading to inaccurate temperature measurements of certain battery locations, affecting battery efficiency.
[0046] 5. Multiple communication wake-up methods require multiple wake-up interfaces, leading to tight microcontroller interface space. Designs based on semiconductor power devices achieve miniaturization, lower internal resistance, and less heat generation, truly realizing miniaturized high power, which is more suitable for the design and application of battery packs with limited space.
[0047] 6. The cost of power relays and drive circuit systems is relatively high, and the contacts are subject to mechanical wear and tear, resulting in a limited lifespan and high maintenance costs. Using transistor power control circuits can effectively solve the problems of cost and ensuring long-term reliability.
[0048] 7. In high-power load applications, the operating current exceeds 100A, and the battery pack capacity also exceeds 100AH. Relay-controlled overcurrent and short-circuit protection relies entirely on fuses. However, the fuse's melting time varies depending on the load's short-circuit condition, which can easily lead to relay contacts burning out and battery cells breaking down and catching fire due to high-current discharge, causing fatal problems. Electronic power control, on the other hand, can achieve a short-circuit control time of 300-500µs. With the assistance of external fuses, the possibility of unpredictable and fatal hazards caused by short circuits in the battery pack output is greatly reduced.
[0049] 8. Due to the mechanical structure of relay contacts, prolonged operation can lead to poor contact or the contacts failing to release. When the contacts fail to release, the battery pack may be completely discharged to 0% capacity, causing irreversible physical damage. Furthermore, forced charging can result in charging protection failure, potentially leading to a deflagration or explosion. Using electronic transistor control can effectively avoid these problems, improve safety, and reduce battery usage costs for users.
[0050] 9. Existing lithium battery packs typically only have one or two communication channels. Adding other peripherals relies entirely on the device controller for expansion, but most controllers do not support any expansion. This design adds multiple communication interfaces and allows for optional safety warnings and user display interfaces to assist the main device in safety monitoring and alerts, making the application more flexible, convenient, and safer.
[0051] 10. The BMS management system using a relay structure primarily employs Hall effect sensors for current sampling. This results in low sampling resolution, significant current detection errors due to the gaps in the current conductors, and large cumulative errors in energy measurement. Furthermore, the sampled current cannot be corrected by software. In contrast, this design uses a zero-drift high-precision operational amplifier to acquire the voltage across a high-precision current sensing resistor. This amplified voltage is then fed into a voltage subtractor for difference calculation before being sent to the metering system to calculate the energy consumption. The operational amplifier input has a zero-point input hardware calibration circuit. Before current sampling, zero-point calibration is performed to eliminate common-mode drift voltage generated by the operational amplifier, achieving truly accurate current sampling and amplification. The amplified signal is completely free of drift voltage. When there is no current, the operational amplifier output automatically calibrates the midpoint voltage, thus maintaining current detection accuracy better than 0.0025%.
[0052] 11. The low-voltage switch controls the output and shutdown interface of the main power supply. Traditional BMS protection boards have limitations such as narrow output voltage range and the polarity cannot be reversed. In actual use, they are prone to damage due to misoperation. This design does not limit the input voltage range, and the system will not be damaged even if the polarity is reversed.
[0053] 12. Improve automated production processes, reduce material costs, save labor costs, and enhance product quality.
[0054] 13. It can realize the production control board of the entire SMT process, which has lower cost, better quality, reduced number of workers, and is more efficient and environmentally friendly. Attached Figure Description
[0055] Figure 1 This is a circuit diagram of the present invention;
[0056] Figures 2a to 2g This is the circuit schematic of the AFE battery pack voltage / current acquisition circuit;
[0057] Figures 3a to 3e Circuit schematic for the charge / discharge current sampling circuit and system power supply:
[0058] Figures 4a-4c This is the circuit schematic of the operational amplifier reference voltage source circuit;
[0059] Figure 5 to Figure 5k Circuit diagram for collecting battery pack discharge current;
[0060] Figure 6 The circuit diagram of the main current sampling circuit;
[0061] Figures 7a to 7h This is the circuit schematic diagram for a communication circuit.
[0062] Figure 8 This is the circuit schematic of a power MOSFET circuit.
[0063] Figures 9a to 9f The circuit schematic for the power supply of the communication circuit;
[0064] Figure 10 This is the circuit diagram of the central control circuit.
[0065] Figure 11 This is the circuit schematic for three NTCs. Detailed Implementation
[0066] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.
[0067] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0068] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0069] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0070] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0071] Reference Figures 1 to 11 This utility model provides an intelligent lithium-ion / sodium-ion battery pack BMS management system, comprising:
[0072] Battery pack, power MOSFET circuit 100, AFE battery pack voltage / current acquisition circuit 200, pre-charge / discharge circuit 300, discharge circuit 400, main current sampling circuit 500, zero current calibration circuit 600, operational amplifier reference voltage source circuit 700, current and voltage sampling amplification circuit 800, central control circuit 900, charge / discharge current sampling circuit 1000, power supply reference voltage source circuit 1100, communication circuit 1200;
[0073] The corresponding terminals of the central control circuit 900 are electrically connected to the corresponding terminals of the AFE battery pack voltage / current acquisition circuit 200, power MOSFET circuit 100, current and voltage sampling amplification circuit 800, pre-charge and discharge circuit 300, discharge circuit 400, charge and discharge current sampling circuit 1000, power reference voltage source circuit 1100, and communication isolation module 1200, respectively.
[0074] The positive terminal of the battery pack is electrically connected to the corresponding terminals of the power MOSFET circuit 100, the AFE battery pack voltage / current acquisition circuit 800, and the power reference voltage source circuit 1100, respectively. The negative terminal of the battery pack is electrically connected to the corresponding terminals of the zero current calibration circuit 600, the AFE battery pack voltage / current acquisition circuit 800, the main current sampling circuit 500, the pre-charge and discharge circuit 300, and the discharge circuit 400, respectively.
[0075] The corresponding terminals of the AFE battery pack voltage / current acquisition circuit 800 are also electrically connected to the corresponding terminals of the power supply reference voltage source circuit 1100, the main current sampling circuit 500, the pre-charge and discharge circuit 300, the discharge circuit 400, and the operational amplifier reference voltage source circuit 700.
[0076] The corresponding terminals of the current and voltage sampling amplification circuit 800 are also electrically connected to the corresponding terminals of the operational amplifier reference voltage source circuit 700, the main current sampling circuit 500, the pre-charge-discharge circuit 300, the slave discharge circuit 400, and the zero current calibration circuit 600.
[0077] Furthermore, the current and voltage sampling amplification circuit 800 includes a battery pack charging current sampling amplification circuit and a battery pack discharging current sampling amplification circuit; the corresponding terminals of the battery pack charging current sampling amplification circuit and the battery pack discharging current sampling amplification circuit are electrically connected to the corresponding terminals of the central control circuit.
[0078] The battery pack charging current acquisition and amplification circuit is used to acquire current information of the battery pack during the charging process, and has three current ranges: 60A-300A, 125mA-75A, and 100mA-4A. The battery pack discharging current acquisition and amplification circuit is used to acquire current information of the battery pack during the discharging process, and can handle current ranges from 1mA to 3000A; this battery pack discharging current acquisition and amplification circuit has five different sampling ranges: 260A-3000A, 60A-300A, 5A-75A, 1mA-1000mA, and 300mA.
[0079] Furthermore, the intelligent lithium-ion / sodium-ion battery pack BMS management system also includes a Bluetooth and display module 1400, a programmable voice module 1500, and a GPS / GSM tracking and transmission circuit 1600. The corresponding terminals of the central control circuit 900 are electrically connected to the corresponding terminals of the Bluetooth and display module 1400, the programmable voice module 1500, and the GPS / GSM tracking and transmission circuit 1600, respectively. The corresponding terminals of the GPS / GSM tracking and transmission circuit 1600 are also electrically connected to the corresponding terminals of the communication circuit 1200, the charge and discharge current sampling circuit 1000, the Bluetooth and display module 1400, and the programmable voice module 1500, respectively.
[0080] Furthermore, the intelligent lithium-ion / sodium-ion battery pack BMS management system also includes a communication activation circuit 1700 and an AND gate communication wake-up circuit 1800; the communication circuit 1200 is electrically connected to the corresponding terminals of the central control circuit 900 via the AND gate communication wake-up circuit 1800 and the communication activation circuit 1700 in sequence.
[0081] Furthermore, the intelligent lithium-ion / sodium-ion battery pack BMS management system also includes three NTCs (1300), and the corresponding terminals of the central control circuit 900 are electrically connected to the corresponding terminals of the AFE battery pack voltage / current acquisition circuit 200 through the three NTCs (1300).
[0082] Furthermore, the power reference voltage source circuit 1100 includes a 12V power supply and a 5V power supply; the corresponding terminals of the 12V power supply are electrically connected to the positive terminal of the battery pack, the corresponding terminals of the GPS / GSM tracking and transmission circuit 1600, and the corresponding terminals of the central control circuit 900, respectively; the corresponding terminals of the 5V power supply are electrically connected to the positive terminal of the battery pack, the corresponding terminals of the central control circuit 900, the Bluetooth and display module 1400, the programmable voice module 1500, and the corresponding terminals of the GPS / GSM tracking and transmission circuit 1600, respectively.
[0083] Specifically, the technical solution of the present invention is described in detail below:
[0084] The specific details of the AFE battery pack voltage / current acquisition circuit 200 are as follows:
[0085] Reference Figures 2a to 2g As shown:
[0086] 1. AFE battery pack voltage acquisition
[0087] Functional Description: In Figure 2a, U4, U6, and U7 are the connecting cables for each battery string in the battery pack; R12, R21, R33, R46, R60, R72, R83, R90, R95, R102, R111, R118, R1, R8, R17, R28, R39, R57, R64, R79, R88, R93, R98, R105, and R117 are current-limiting and battery energy-balancing resistors; Q4, Q7, Q9, Q11, Q13, and Q14 are the resistors for current limiting and battery energy balancing. 5. Q17, Q19, Q20, Q23, Q25, Q28, Q2, Q3, Q5, Q8, Q10, Q12, Q14, Q16, Q18, Q21, Q22, and Q24 are battery hardware equalization transistors. They send the voltage collected from the cable to U5, which is an AFE analog acquisition chip. The AFE chip has 18-bit, 16-bit, and 14-bit current acquisition resolutions. Finally, U8 reads the data from the AFE's internal registers via SPI communication. U5 sends the collected battery voltage and current analog values to... Figure 2b U8 is used for ADC conversion calculations. U5 and U8 communicate via an SPI interface. Pins 96 and 95 of U8 are connected to pins 36 and 37 of U5. The internal registers of U5 are read and written through the SPI interface, and the actual value is calculated according to the formula based on the read register values.
[0088] 2. AFE current sampling
[0089] Figure 2c R126 and R127 are current sampling resistors. The integration acquisition circuit composed of R314-R339 averages the voltages sampled by R324-R330 and sends them to the I+ and I- networks. Each power MOSFET has an independent current sensing resistor, which is an independent current branch in the current loop, equivalent to a complete parallel branch circuit. The voltages across each current sensing resistor are integrated and averaged to output as the I+ and I- signals. Since the value of the integrating resistor is much larger than that of the current sensing resistor, the shunting effect can be ignored, so there is no resonance and the sampling signal is stable.
[0090] 3. Charge / discharge MOSFET control and drive
[0091] Figure 2ePin 31 of U5 is the output pin of the BMS discharge drive MOSFET. When there is no discharge protection event, it outputs a high level of 12V; when there is a discharge protection event, it outputs a low level. This output is sent to a Darlington push-pull circuit composed of Q41, Q44, Q51, Q47, Q56, Q57, Q42, Q52, Q45, Q48, Q49, Q54, and Q55. This circuit uses two independent push-pull amplification channels (DHG1 and DHG2) to drive the two discharge power MOSFETs (Q93-Q100, Q103-Q108, and Q110-Q117). Since more than 40 power MOSFETs need to be connected in parallel, the parasitic capacitance of the MOSFETs is large and cannot be ignored. Without current amplification of the 12V signal from pin 31 of U5, the output current is insufficient to quickly switch the more than 40 power MOSFETs. Using a push-pull drive provides a sufficiently strong driving capability to quickly switch the discharge power MOSFETs. Due to the large output current capability of the push-pull circuit, it can also effectively prevent MOSFETs from being switched too quickly. The gate-source pin cannot be turned on normally due to leakage current caused by external factors, which causes a drop in drive voltage. When a short circuit occurs in the load, the current of U28B, U29B or U36B detects that the short circuit condition is met, and pin 31 of U5 goes low. The push-pull circuit can quickly discharge the gate-source charge of the MOSFET and close the channel between the drain and the source, avoiding avalanche due to excessive time in the saturation region.
[0092] Pin 34 of U5 is the control pin for the charging drive MOSFET. It outputs 12V when no protection event occurs, and is in a high-impedance open-circuit state when a protection event occurs. Figure 2f Q43, Q53, Q50, and Q46 are Darlington push-pull drive circuits for charging MOSFETs, used to enhance the turn-on and turn-off capabilities of Q69-Q92 charging power MOSFETs.
[0093] 4. Pre-charge and discharge:
[0094] refer to Figure 2g When a battery enters discharge protection or deep discharge mode, normal charging is unlikely to activate it. Furthermore, when the cell voltage is too low, the increased internal resistance of the cell means that direct high-current charging can cause overheating, severely damaging the cell and potentially leading to a charging fire. Therefore, a low-current slow charge is necessary to gradually increase the battery voltage until it recovers from discharge or is activated. If the battery fails to activate when the charger is connected, the CHG_EN pin provides voltage to charge the battery until it is activated or recovers from discharge.
[0095] Control logic:
[0096] 1. When the battery voltage enters the undervoltage protection of the discharge cell, the DSG level changes from 1 to 0, CQ1 is cut off, CQ4 is turned on, CQ5 is turned on, and CQ8 is turned on. R483 is a high-power metal resistor. At this time, R483 is connected in series in the charging circuit through CQ8. The battery charging current I is equal to the charger voltage U1 and the battery pack voltage U2. At this time, the charging current I = (U1-U2) / R483. By simply setting the resistance value of R483 according to the total capacity of the battery pack, a low-voltage charging current that does not damage the battery can be achieved.
[0097] 2. When a single cell is undervoltage, DSG changes from 1 to 0, CQ2 is cut off, CQ3 is turned on, Q145 is turned on, and CQ7 is turned on. After CQ7 is turned on, it will bypass the charging level of the main charging circuit of the battery, forcibly pulling the main charging low. Q53 and Q50 are turned on, the main charging MOSFET drive is 0, and the charger cannot charge through the main charging circuit. At this time, only the pre-charging circuit works.
[0098] 3. When the voltage of a single battery cell exceeds the over-discharge protection recovery voltage, the DSG level changes from 0 to 1. CQ1 is turned on, CQ4 is turned off, CQ5 is turned off, and CQ8 is turned off. The pre-charge transistor Q8 no longer starts small-current charging. After DSG changes to 1, CQ2 is turned on, CQ3 is turned off, Q145 is turned off, and CQ7 is turned off. After CQ7 is turned off, the drive signal of the main charging circuit is no longer bypassed, the main charging circuit enters the normal charging state, and the battery enters the high-current normal charging mode.
[0099] 4. Through the above switching control, the functions of pre-charging in the undervoltage state and main charging in the normal voltage state are realized. Because the switching is implemented purely in hardware, it can improve stability and avoid software errors that may cause control errors and lead to abnormal charging and safety hazards.
[0100] II. Charge / discharge current sampling circuit 1000 and system power supply:
[0101] Reference Figures 3a to 3d As shown:
[0102] 1. Power supply and current consumption acquisition of MCU integrated operational amplifier system
[0103] Figure 3aThe BM6203AH-5V can be input via the battery pack's positive terminal and a DC 12V power supply. After stepping down the 12V input, the BM6203AH-5V outputs 5V, which powers the subsequent stages via D3 and R27. R41 is the system current sampling resistor, and U3 is a differential current amplifier. It amplifies the system current signal by sampling the voltage across R41. U3 is a zero-drift ultra-low-power op-amp with a Voss drift accuracy of 5µV. Therefore, the minimum sampling current resolution is 0.005mV / 200mR = 0.025mA, meaning a system current greater than 25µA can be sampled. The signal differentially sampled by U3 is amplified 150 times and then sent to the ADC port (pin 24) of U8 for sampling. U8 can then perform coulombic measurement of the system current, enabling the main control system to achieve coulombic sampling in any state. This ensures accurate SOC measurement even during long-term storage or operation of the battery pack. The UCT78HC33B provides the 3.3V power supply for the MCU. Q62 is the reference voltage control switch for the integrated operational amplifier in the current acquisition circuit. Q62 is also a controllable power supply electronic switch for the integrated operational amplifier chip in the current acquisition amplifier circuit. Low-power control of the operational amplifier circuit is achieved through the switching control of Q61 and Q62. The VDC power supply is provided by the AFE chip. When the AFE chip is in normal operation, the output voltage of the BM6203AH-5V chip passes through a Schottky diode to output approximately 5V - 0.3V = 4.7V, while the VDC chip provides approximately 5V. At this time, the 5V input voltage of the UCT78HC33B is provided by the VDC chip, supplying power to the microcontroller. When entering low-power sleep mode, the VDC output is 0V, and the input voltage of the UCT78HC33B is provided by the 5V output of the BM6203AH-5V chip, supplying power to the microcontroller.
[0104] 2. Current acquisition of DC 12V and DC 5V power supply circuits
[0105] Figures 3b-3d U14 and U12 are switching buck constant voltage drivers with settable output current. U14 and U12 are 12 / 2A 5V / 1A high-voltage to low-voltage DC power conversion chips, respectively. The power consumption generated by the DC power supply circuit is amplified by U35 and then sent to the microcontroller U8. R415 is the total sampling resistor for DC power supply current. After U35 differentially amplifies the voltage signal across R415, it is sent to the microcontroller U8 to calculate the power consumed by the DC power supply and incorporate it into the SOC compensation algorithm.
[0106] Q58 and Q60 are the enable controls for the DC-DC converter chip. When Q58 and Q60 are enabled to turn on the DC-DC converter chip, U35 can amplify the signal and collect the current. The sampling accuracy of the op-amp is 5uV, and the minimum sampling current is 0.005mV / 50mR=100uA. When Q58 and Q60 are enabled to turn off the DC-DC converter chip, the power supply circuit consumes less than 5uA of current. Therefore, under any conditions, the current consumed by the power supply circuit itself can be accurately collected, ensuring the accuracy of the SOC capacity.
[0107] III. Operational Amplifier Reference Voltage Source Circuit
[0108] Reference Figures 4a-4c The AFE chip provides a high-precision, low-drift voltage reference. Due to the limited load capacity of the voltage reference, a differential amplifier, U31A, a high-precision zero-drift operational amplifier, is used to amplify the voltage reference provided by the AFE chip to a ratio of (200+36) / 200=1.18. Then, a voltage follower U38B is used to achieve an ideal 3.1V voltage source with ultra-high precision, stability, and strong load capacity, providing a high-precision voltage reference for the operational amplifier and the main power supply sampling circuit. Through the controlled electronic switches Q65 and Q61, a high-precision comparison voltage source is provided to U25, U26, U27, U28, U29, U30, U33, and U38. Therefore, the VREF reference voltage pin of the microcontroller can also receive a high-precision reference voltage source with strong load capacity.
[0109] IV. Current and Voltage Sampling Amplification Circuit: 800 pairs of multi-channel high-resolution current acquisition and processing circuits covering an operating range of 1mA-3000A.
[0110] 1. Battery pack charging current acquisition
[0111] Reference Figures 5a to 5e The charging current detection has three levels: 60A-300A, 125mA-75A, and 100mA-4A. During charging, the charging current is calculated by sequentially scanning these three levels, and the system then determines whether to run in main charging mode or pre-charging mode. If no sample value is obtained when detecting the 60A-300A current level for a period of time, the 125mA-75A level is activated for sampling. If no current value is successfully sampled either, the 100mA-4A level is activated. The working principle of these three levels is similar. For example, when the microcontroller polls these three levels and detects a current in the 100mA-4A level, U30A amplifies and compares the difference, while U30B outputs a reverse voltage signal to the U8 MCU. The U8 MCU then... Figure 5dWhen the PDSG is enabled, a pre-charge mode is entered to pre-charge the battery with a small current. After a period of pre-charging, the main charging mode is turned on, which means the charging MOSFET is turned on to charge with a large current. At this time, the U8 MCU will switch the current detection range sequentially until a certain range of 60A-300A or 125mA-75A can be collected normally.
[0112] The advantage of using operational amplifiers U30A, U27A, and U25A for differential operation is that they output a standard 3.1V reference voltage when there is no current. When there is charging current, the output voltage of U30A, U27A, and U25A is 3.1V - [(I+) - (I-)] * Rsense, where Rsense is the value of the main current sampling resistor. When the charging current is larger, the output voltage of U30A is lower, as can be seen from Vout = Vref - Vin. This avoids the situation where the signal amplified by U25A after amplification of a small current does not reach the minimum voltage input resolution of the microcontroller, thus limiting the accuracy of the minimum detection current and ensuring high-precision detection even with small current.
[0113] 2. Battery pack discharge current acquisition
[0114] Reference Figures 5f to 5k 1. U29A, U26A, U28A, and U33A are five differential amplifiers with different amplification factors, used to achieve different current amplification factors for different current ranges, thus preventing voltage overflow after amplification when the current increases. U29B, U26B, U28B, U33B, and U36B are voltage difference comparators. When there is no discharge current, U29B, U26B, U28B, and U33B output a 3.1V reference voltage. As the current increases, the output voltage of U29B, U26B, U28B, and U33B decreases from 3.1V, as shown by Vout=VREF-Vin. This avoids the dead-zone voltage acquisition problem of the U8 microcontroller near 0V.
[0115] 2. Figure 5f It can be seen that when the voltage acquisition is at a maximum of 3000A, and the amplification factor AV=7.5, the differential amplification factor of the last bit is 1, and the output voltage is Vout = 3.1-(0.002*3000*7.5 / 24) = 1.225V. This is within the accuracy of the microcontroller acquisition, which can ensure that the microcontroller can acquire the correct voltage.
[0116] 3. Figure 5iIt can be seen that when the minimum current sampling is 1mA and the amplification factor AV=200, the differential amplification factor of the last bit is 1, and the output voltage is Vout = 3.1-(0.015*0.001*200) = 3.097V. The minimum voltage resolution of the microcontroller is 3.3 / 2^12 = 3.3 / 4096 = 0.0008058594. The sampled voltage is much larger than the voltage acquisition resolution of the microcontroller.
[0117] 4. Figure 5j The system consists of a differential amplifier U36A and a comparator U36B. When the current is 300mA, the output voltage of the differential amplifier is 0.015*0.3*200=0.9V, and the voltage at the negative terminal of U36B is 3.1 / (240+100)*100 =0.91V. Therefore, when the current is less than 300mA, the output is low after comparison by U36B.
[0118] 5. Figures 5f-5j Five different current ranges are available. Sampling can begin with the maximum current range on U32. If no current is sampled, the current can be switched sequentially from U8 down to U32 (Figure 3-). Figure 5j The current sampling range in the program can achieve a sampling range of 1mA-3000A.
[0119] 6. Figure 5k The battery pack discharge current sampling, with a sampling range of 1mA-1000mA, is a core functional part of this technology. The main discharge circuit's current sampling range is 100mA-3000A. When the discharge current is less than 100mA, the main discharge circuit cannot identify it. Prolonged discharge in this case will cause SOC measurement errors, resulting in severely inaccurate charge readings. When the battery pack discharge current is less than 300mA, the MCU controls the SLAVE_DG level to change from 0 to 1, turning on Q118. R292, R293, and R294 are PTC positive temperature coefficient self-recovering thermistor power devices, which limit the maximum discharge current after Q118 is turned on, preventing damage to Q118 due to short circuits or overloads in external devices. After Q118 is turned on, the discharge current flows through R331 to the battery pack's total negative terminal. R331 has a resistance of 0.015R. The voltage Uqi on the differential line QI+QI_ is I*0.015. The Uqi output is sent to the U30 differential amplifier. The U30 is a zero-drift high-precision integrated operational amplifier with an input offset voltage better than 2uV. Therefore, it can detect a load discharge current of 1mA. Even if the external device is in a standby low-current state, as long as the current consumption is greater than 1mA, the BMS system can effectively measure its energy consumption, thereby ensuring that the SOC of the load device under long-term low-current state due to energy consumption is not seriously inaccurate.
[0120] 7. When the battery pack discharge current is greater than 300mA, the MCU will automatically control the Master_DG level to change from 0 to 1, the main discharge circuit will work normally, the Master_DG will be turned on for a certain period of time to ensure that the main discharge circuit is in normal condition, and then the SLAVE_DG will be turned off from 1 to 0 to shut down the small current discharge circuit.
[0121] In summary, when the battery pack discharge current is greater than 300mA, it is sampled by the main discharge circuit and operated under load; when it is less than 300mA, it is sampled by the slave discharge circuit and operated under load.
[0122] V. Precise and stable main current sampling circuit 500
[0123] Reference Figure 6 In high-power multi-MOSFET parallel applications, the traditional approach is to directly connect the drain (D) and source (S) terminals of the power MOSFETs in parallel. However, when multiple power MOSFETs are directly connected in parallel, the inconsistent internal resistance changes of the MOSFETs under high current operation can easily lead to inconsistent current fluctuations in each MOSFET, resulting in oscillation. In this design, each power MOSFET has an independent current sensing resistor, forming an independent current branch in the current loop, equivalent to a complete parallel branch circuit. Figure 6 R323, R324, R325, R326, and R327 are independent current sensing resistors, while R314, R315, R316, R317, R318, R332, R333, R334, R335, and R336 are integrating resistors. The voltage across each current sensing resistor is integrated and the average value is sent out as the I+ and I- signals. Since the value of the integrating resistor is much larger than that of the current sensing resistor, the shunting effect is negligible, thus preventing resonance and ensuring a stable and reliable sampling signal.
[0124] The current calibration switch in the diagram is crucial. Before the microcontroller reads the current AD value from the main current operational amplifier, it first sends a high level to I_CORRECT to turn on the current calibration switch. Since the current calibration switch consists of two MOSFETs connected in parallel, its on-resistance is in the mR range. The integrating resistor formed by R314 R315 R316 R317 R318 R332 R333 R334 R335 R336 from I+ and I- is much larger than the internal resistance of the current calibration switch. It should be set to be at least 100 times larger than the switch's internal resistance. This is equivalent to short-circuiting the input terminals of the operational amplifier and the AFE, thereby enabling the microcontroller to calibrate the Vos drift voltage value of each channel's operational amplifier in the zero-current state. After calibration, the current AD value is calculated, thus achieving true microcontroller software algorithm drift current compensation.
[0125] VI. Description of Communication Circuit 1200:
[0126] Reference Figures 7a to 7h The GPS DTU module communication includes a GPS DTU module communication circuit, a MOSBUS-RUT communication circuit, a CANBUS communication circuit, a serial voice interface circuit, and a communication port.
[0127] 1. GPS DTU module communication circuit
[0128] The GPS DTU module's communication power supply is directly drawn from DC12V. The power supply adopts a non-isolated method and can power DTU load devices with a capacity of up to 12V3A. The data port is isolated for communication.
[0129] 2. MOSBUS-RUT communication circuit
[0130] Because MODBUS-RTU needs to connect to external devices, it uses a method of power and signal isolation for communication, which is safer and more reliable.
[0131] 3. CANBUS communication circuit
[0132] The isolated communication method is adopted. U37 and U40 are data isolation transceivers, U39 and U41 are CAN data transceivers, and U39 and U43 are common-mode filters. This can effectively suppress low differential-mode noise signal interference sources, making it difficult for control signals to be distorted in high-speed signals. In addition, power supply and communication are isolated to ensure that external signal interference can be reduced during CAN communication.
[0133] 4. Serial voice interface circuit
[0134] It serves as an interface for serial voice modules or a UART interface for data isolation, but the power supply is not isolated.
[0135] 5. Communication port definition.
[0136] The J8 socket integrates a display interface, an isolated MODBUS-RTU interface, a serial voice speaker interface, a GPS DTU tracking module interface, a serial Bluetooth communication interface, two CAN interfaces, and two serial ports.
[0137] VII. Power MOSFET circuit 100
[0138] Reference Figure 8 The discharge MOSFET and the charging MOSFET are connected in parallel. A damping resistor is added to the gate. The value of the damping resistor is calculated based on the drive current of the MOSFET drive circuit and the CISS input junction capacitance of the MOSFET to prevent resonance at the gate when the MOSFET is turned on and off.
[0139] VIII. Power Supply for Communication Circuits
[0140] Reference Figures 9a to 9f U14 is a 12V power supply chip that powers the GPS DTU module. It has a current carrying capacity of 12V 3A. When the voltage of a single battery cell is lower than 2.2V, 12V_EN is at a high level, Q60 is turned on, and U14 is turned off to achieve low power consumption.
[0141] U12 is a 5V power supply chip that provides power for isolated communication and voice interfaces. When the system is powered off, in hibernation, without communication, or without charging / discharging current, 5V_EN is at a high level, Q58 is turned on, and U12 is enabled and turned off to achieve low power consumption.
[0142] OPA_EN enables the op-amp power supply and reference voltage. When OPA_EN is high, the op-amp power supply and reference voltage are enabled; when it is low, they are disabled.
[0143] BLE_PWR enables Bluetooth power supply. When BLE_PWR outputs a high level, Q68 and Q64 are turned on to provide power. When BLE_PWR outputs a low level, Q68 and Q64 are turned off to achieve low power consumption.
[0144] When there is no communication or charging / discharging current, the U8 microcontroller will enter sleep mode after 10 seconds. When there is communication, charging / discharging current, or a low-voltage switch is activated, it will automatically wake up and work at full speed.
[0145] 2. Isolated communication power supply
[0146] U11 and U62 are isolated power supply PWM chips. The input power supply comes from a DC 5V power supply, and the communication circuit uses a completely isolated channel powered by this power supply.
[0147] 3. Communication Wake-up
[0148] An optocoupler is used to wake up the BMS via external communication. When an external signal is input, the optocoupler LEDs light up, triggering Q129, Q130, Q131, Q132, Q133, Q134, and Q135 to conduct. The WAKE_UP signal is sent to the AND gate for judgment, and the signal is sent to the interrupt trigger port of the U8 microcontroller to wake up the microcontroller from sleep.
[0149] IX. Description of Central Control Circuit 900
[0150] Reference Figure 10The U8 is a central controller microcontroller system. The control program is written using an RTOS / RTT task programming approach, enabling rapid acquisition of multi-channel ADC data. The acquisition speed for both main and auxiliary current ADCs is better than 1ms. During main current ADC acquisition, a current zero-point calibration is performed to eliminate operational amplifier drift voltage errors. A 32kHz precise clock is used for timing, and the log data in the FLASH memory can be dated. Both the AFE and FLASH memory use SPI communication.
[0151] 10. NTC Temperature Acquisition
[0152] Reference Figure 11 The system uses a B3950 / 100K 1% NTC acquisition probe. To reduce power consumption, the negative terminal of the NTC is used as the common terminal and connected to the gate of the electronic switch. The source of the electronic switch is connected to the MCU's IO pin. The microcontroller uses a polling scan method to turn on the electronic switch. The AFE can acquire the temperatures of three groups of NTCs, PA1, PA2, and PA3, respectively. The U8 MCU reads the temperature from the AFE register to obtain the temperature, thus achieving low power consumption. The advantage of this approach is that when there are not enough AFE temperature acquisition pins, a group scanning design can be used. Theoretically, this NTC grouping can be continuously added, solving the current problem of insufficient AFE temperature acquisition ports.
[0153] The technical solution of this utility model has the following beneficial effects:
[0154] 1. High-power MOSFETs replace traditional relay solutions. The operating current of all systems on the BMS board is collected with an accuracy better than 50uA. The charging / discharging main circuit current collection accuracy ranges from 1mA to 3000A, ensuring correct SOC even during long-term storage or operation of the battery pack. This effectively prevents damage to the battery pack, ensures no power outages during normal battery use, and reduces product costs.
[0155] 2. A positive temperature coefficient PTC power resistor is used as the input resistor of the discharge circuit to isolate the discharge circuit from the coulomb counter circuit, reducing the possibility of further damage to components due to high power loss or energy discharge.
[0156] 3. Each power MOSFET uses an independent current sensing resistor. The voltage across each current sensing resistor is integrated and the average value is sent out as the I+ and I- signals. Since the average value of the integrating resistor is greater than that of the current sensing resistor, integration can be performed to reduce measurement error, and a portion of the current can be diverted in parallel to prevent excessive current from damaging internal components when connected to the detection circuit.
[0157] 4. Due to the use of power MOSFETs, parasitic capacitance exists within the MOSFETs. Since high-power output requires numerous power MOSFETs to control the circuit's switching, the resulting capacitance after parallel connection cannot be ignored. This parasitic capacitance slows down the switching on and off of the electronic switch. Currently, there are few temperature sampling ports, leading to inaccurate temperature measurements of certain battery locations, affecting battery efficiency.
[0158] 5. Multiple communication wake-up methods require multiple wake-up interfaces, leading to tight microcontroller interface space. Designs based on semiconductor power devices achieve miniaturization, lower internal resistance, and less heat generation, truly realizing miniaturized high power, which is more suitable for the design and application of battery packs with limited space.
[0159] 6. The cost of power relays and drive circuit systems is relatively high, and the contacts are subject to mechanical wear and tear, resulting in a limited lifespan and high maintenance costs. Using transistor power control circuits can effectively solve the problems of cost and ensuring long-term reliability.
[0160] 7. In high-power load applications, the operating current exceeds 100A, and the battery pack capacity also exceeds 100AH. Relay-controlled overcurrent and short-circuit protection relies entirely on fuses. However, the fuse's melting time varies depending on the load's short-circuit condition, which can easily lead to relay contacts burning out and battery cells breaking down and catching fire due to high-current discharge, causing fatal problems. Electronic power control, on the other hand, can achieve a short-circuit control time of 300-500µs. With the assistance of external fuses, the possibility of unpredictable and fatal hazards caused by short circuits in the battery pack output is greatly reduced.
[0161] 8. Due to the mechanical structure of relay contacts, prolonged operation can lead to poor contact or the contacts failing to release. When the contacts fail to release, the battery pack may be completely discharged to 0% capacity, causing irreversible physical damage. Furthermore, forced charging can result in charging protection failure, potentially leading to a deflagration or explosion. Using electronic transistor control can effectively avoid these problems, improve safety, and reduce battery usage costs for users.
[0162] 9. Existing lithium battery packs typically only have one or two communication channels. Adding other peripherals relies entirely on the device controller for expansion, but most controllers do not support any expansion. This design adds multiple communication interfaces and allows for optional safety warnings and user display interfaces to assist the main device in safety monitoring and alerts, making the application more flexible, convenient, and safer.
[0163] 10. The BMS management system using a relay structure primarily employs Hall effect sensors for current sampling. This results in low sampling resolution, significant current detection errors due to the gaps in the current conductors, and large cumulative errors in energy measurement. Furthermore, the sampled current cannot be corrected by software. In contrast, this design uses a zero-drift high-precision operational amplifier to acquire the voltage across a high-precision current sensing resistor. This amplified voltage is then fed into a voltage subtractor for difference calculation before being sent to the metering system to calculate the energy consumption. The operational amplifier input has a zero-point input hardware calibration circuit. Before current sampling, zero-point calibration is performed to eliminate common-mode drift voltage generated by the operational amplifier, achieving truly accurate current sampling and amplification. The amplified signal is completely free of drift voltage. When there is no current, the operational amplifier output automatically calibrates the midpoint voltage, thus maintaining current detection accuracy better than 0.0025%.
[0164] 11. The low-voltage switch controls the output and shutdown interface of the main power supply. Traditional BMS protection boards have limitations such as narrow output voltage range and the polarity cannot be reversed. In actual use, they are prone to damage due to misoperation. This design does not limit the input voltage range, and the system will not be damaged even if the polarity is reversed.
[0165] 12. Improve automated production processes, reduce material costs, save labor costs, and enhance product quality.
[0166] 13. It can realize the production control board of the entire SMT process, which has lower cost, better quality, reduced number of workers, and is more efficient and environmentally friendly.
[0167] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.
Claims
1. A smart lithium-ion / sodium-ion battery pack BMS management system, characterized in that, include: Battery pack, power MOSFET circuit, AFE battery pack voltage / current acquisition circuit, pre-charge and discharge circuit, discharge circuit, main current sampling circuit, zero current calibration circuit, operational amplifier reference voltage source circuit, current and voltage sampling amplification circuit, central control circuit, charge and discharge current sampling circuit, power supply reference voltage source circuit, communication circuit; The corresponding terminals of the central control circuit are electrically connected to the corresponding terminals of the AFE battery pack voltage / current acquisition circuit, power MOSFET circuit, current and voltage sampling amplification circuit, pre-charge and discharge circuit, discharge circuit, charge and discharge current sampling circuit, power reference voltage source circuit, and communication isolation module, respectively. The positive terminal of the battery pack is electrically connected to the corresponding terminals of the power MOSFET circuit, the AFE battery pack voltage / current acquisition circuit, and the power reference voltage source circuit, respectively. The negative terminal of the battery pack is electrically connected to the corresponding terminals of the zero current calibration circuit, the AFE battery pack voltage / current acquisition circuit, the main current sampling circuit, the pre-charge-discharge circuit, and the slave discharge circuit, respectively. The corresponding terminals of the AFE battery pack voltage / current acquisition circuit are also electrically connected to the corresponding terminals of the power supply reference voltage source circuit, the main current sampling circuit, the pre-charge and discharge circuit, the slave discharge circuit, and the operational amplifier reference voltage source circuit. The corresponding terminals of the current and voltage sampling amplification circuit are also electrically connected to the corresponding terminals of the operational amplifier reference voltage source circuit, the main current sampling circuit, the pre-charge-discharge circuit, the slave discharge circuit, and the zero-current calibration circuit.
2. The intelligent lithium-ion / sodium-ion battery pack BMS management system according to claim 1, characterized in that, The current and voltage sampling amplification circuit includes a battery pack charging current sampling amplification circuit and a battery pack discharging current sampling amplification circuit; the corresponding terminals of the battery pack charging current sampling amplification circuit and the battery pack discharging current sampling amplification circuit are electrically connected to the corresponding terminals of the central control circuit.
3. The intelligent lithium-ion / sodium-ion battery pack BMS management system according to claim 2, characterized in that, The battery pack charging current acquisition and amplification circuit is used to acquire the current information of the battery pack during the charging process, and has three current levels: 60A-300A, 125mA-75A, and 100mA-4A.
4. The intelligent lithium-ion / sodium-ion battery pack BMS management system according to claim 2, characterized in that, The battery pack discharge current acquisition and amplification circuit is used to acquire the current information of the battery pack during the discharge process, and can process current ranges from 1mA to 3000A. The battery pack discharge current acquisition and amplification circuit has five different sampling ranges: 260A-3000A, 60A-300A, 5A-75A, 1mA-1000mA, and 300mA.
5. The intelligent lithium-ion / sodium-ion battery pack BMS management system according to claim 2, characterized in that, The intelligent lithium-ion / sodium-ion battery pack BMS management system also includes a Bluetooth and display module, a programmable voice module, and a GPS / GSM tracking and transmission circuit. The corresponding terminals of the central control circuit are electrically connected to the corresponding terminals of the Bluetooth and display module, the programmable voice module, and the GPS / GSM tracking and transmission circuit, respectively. The corresponding terminals of the GPS / GSM tracking and transmission circuit are also electrically connected to the corresponding terminals of the communication circuit, the charge and discharge current sampling circuit, the Bluetooth and display module, and the programmable voice module, respectively.
6. The intelligent lithium-ion / sodium-ion battery pack BMS management system according to claim 5, characterized in that, The intelligent lithium-ion / sodium-ion battery pack BMS management system also includes a communication activation circuit and an AND gate communication wake-up circuit; the communication circuit is electrically connected to the corresponding terminals of the central control circuit in sequence via the AND gate communication wake-up circuit and the communication activation circuit.
7. The intelligent lithium-ion / sodium-ion battery pack BMS management system according to claim 6, characterized in that, The intelligent lithium-ion / sodium-ion battery pack BMS management system also includes three NTCs. The corresponding terminals of the central control circuit are electrically connected to the corresponding terminals of the AFE battery pack voltage / current acquisition circuit through the three NTCs.
8. The intelligent lithium-ion / sodium-ion battery pack BMS management system according to claim 7, characterized in that, The power reference voltage source circuit includes a 12V power supply and a 5V power supply; the corresponding terminals of the 12V power supply are electrically connected to the positive terminal of the battery pack, the corresponding terminals of the GPS / GSM tracking and transmission circuit, and the corresponding terminals of the central control circuit, respectively; the corresponding terminals of the 5V power supply are electrically connected to the positive terminal of the battery pack, the central control circuit, the Bluetooth and display module, the programmable voice module, and the corresponding terminals of the GPS / GSM tracking and transmission circuit, respectively.