A 3c level ratio fast charging method and system for an electric bicycle

Abstract

The application provides a 3C-ratio fast charging method and system for an electric bicycle, and relates to the technical field of fast charging. The charging method comprises the following steps: after the fast charging pile and the battery complete communication handshake and access; when the SOC is less than or equal to 10%, pre-charging is carried out at 3A, and the active balancing of the battery cell is simultaneously carried out; when the SOC reaches 10% and the temperature reaches the standard, 200A constant current is output to carry out 3C-ratio charging; during the charging process, differential pressure balancing, temperature current, and power topology phase error three-layer linkage control are carried out; when the SOC rises to 90%, the constant voltage mode is switched, the current gradually decays with the saturation of the lithium embedding of the battery cell, and the battery cell balancing is continuously carried out; when the charging current falls to the cut-off threshold, the power output is cut off, and the heat management module is delayed, cooled and stopped. The charging time of the battery from 10% SOC to 90% SOC can be controlled within 5-10 minutes. Through full-cycle balancing and multi-dimensional linkage control, the problems of the pressure difference and temperature rise of the high-ratio charging battery cell are inhibited, the charging efficiency, the operation safety and the battery consistency are considered, and the fast energy supplement application scene of the electric bicycle is adapted.

Description

Technical Field

[0001] This application relates to the field of fast charging technology, and more specifically, to a 3C-level high-rate fast charging method and system for electric bicycles. Background Technology

[0002] Current electric bicycle charging equipment generally suffers from low charging power and long charging times. Conventional household chargers typically have a power output of 200W-400W and an operating current of only 4A-8A, requiring 6-8 hours to fully charge a 48V 30Ah battery. Even with existing fast charging technologies generally employing a 1C charging rate, charging time still takes 1.5-2 hours, failing to meet users' needs for rapid energy replenishment and on-the-go charging. Furthermore, traditional chargers often use flyback topologies, resulting in low overall power density, poor conversion efficiency, and severely inadequate high-power charging adaptability.

[0003] Existing commercial DC fast charging stations are mainly designed for high-voltage platforms in new energy vehicles, with output voltage ranges mostly between 200V and 750V. They cannot be directly adapted to the 50-200V low-voltage battery systems of electric bicycles. Adding multi-stage step-up / step-down circuits to achieve compatibility would result in a complex overall structure, increased power loss, and aggravated operating temperature rise, leading to poor equipment compatibility and widespread adoption. Furthermore, the industry currently uses a large number of proprietary fast charging protocols with inconsistent communication standards. Even if the new national standard's mutual recognition and collaboration protocols are met, shortcomings remain, including poor compatibility, limited fast charging start-up conditions, and insufficient safety verification dimensions.

[0004] In terms of battery management and balancing control, existing BMS (Battery Management Systems) only have basic voltage detection, temperature acquisition, and simple balancing protection functions, which have significant technical shortcomings when facing high-rate and high-current charging conditions. Ultra-high-rate charging significantly amplifies the polarization differences of individual cells, causing rapid degradation of battery pack voltage consistency. Traditional balancing circuits have slow response speeds and low balancing efficiency, and cannot suppress dynamic voltage differences in real time. At the same time, the abnormal protection response delay of traditional BMS can reach 200ms to 500ms, which is too late to meet the millisecond-level safety control requirements of 3C ultra-high-rate fast charging.

[0005] In terms of heat dissipation and temperature control, existing air-cooled heat dissipation structures have long heat transfer paths and low temperature measurement accuracy, making it impossible to accurately capture the instantaneous temperature rise changes during ultra-high-power fast charging. High-end liquid cooling solutions are costly and bulky, making them difficult to adapt to the miniaturization and low-cost assembly requirements of electric bicycles. Traditional centralized temperature monitoring modes cannot achieve precise temperature control of individual battery cells. During high-current charging, large temperature differences between individual cells and prominent local overheating problems are easily caused, which can easily lead to lithium plating on the negative electrode, battery life degradation, and in severe cases, thermal runaway safety hazards. In addition, existing ultra-high-rate fast charging systems generally rely on 380V three-phase power supply, which cannot be adapted to household 220V mains power scenarios, seriously restricting the widespread application of civilian fast charging technology. Summary of the Invention

[0006] To address the aforementioned technical issues, this invention provides a 3C-level high-rate fast charging method for electric bicycles. By constructing a two-level power conversion fast charging architecture adapted to 220V AC mains power, combined with a multi-dimensional battery access verification mechanism, a segmented high-rate charging strategy, a bidirectional linkage control logic between the BMS and fast charging piles, and full-cycle continuous balancing and gradient heat dissipation prediction technology, ultra-high-rate safe fast charging of low-voltage electric vehicle batteries is achieved. This invention abandons the traditional single constant current and constant voltage charging mode. It solves the problems of slow charging speed, incompatibility between high and low voltage platforms, and low high power conversion efficiency of existing technologies by pre-charge voltage difference correction, 3C high current three-layer linkage power regulation, constant voltage current gradient dynamic balancing, and cutoff timing prediction shutdown control. At the same time, it overcomes the technical defects of high-rate charging cells such as polarization dispersion, large temperature difference between individual cells, response lag, temperature rise runaway, and negative electrode lithium deposition by cell full-time active balancing, fine temperature linkage speed regulation, current gradient lithium intercalation state recognition, and pre-heat dissipation standby mechanism. Under the premise of meeting the new national standard mutual recognition collaborative charging protocol, it significantly improves the fast charging efficiency, charging consistency, and overall safety and stability of low-voltage electric bicycle batteries.

[0007] Firstly, this application proposes a 3C-level high-rate fast charging method for electric bicycles, applied to a fast charging system powered by 220V AC mains, comprising a two-stage power conversion fast charging station and a matching 48V 30Ah fast charging battery. The fast charging station is equipped with a bidirectional interleaved PFC rectifier unit, a three-phase interleaved parallel BUCK buck converter, and a microprocessor control unit; the fast charging battery incorporates an active balancing BMS, a composite heat dissipation structure, and an independent thermal management module; the charging method includes: S1. The fast charging station and the battery complete a communication handshake and verify the battery charging access conditions. Only after the verification is passed will 3C power fast charging be started. S2. When the battery SOC ≤ 10%, it is pre-charged with a current of 3A and the cells are actively balanced simultaneously to eliminate cell polarization and initial voltage difference. S3. When the battery SOC reaches 10% and the cell temperature is below the safe temperature threshold, the fast charging pile outputs a constant current of 200A to achieve 3C rate charging. During the charging process, three-layer linkage control is executed simultaneously. The three-layer linkage control includes differential pressure equalization linkage control, temperature and current linkage control, and power topology phase reversal control. S4. After the SOC reaches 90%, the constant voltage charging mode is switched. The charging current naturally decreases as the lithium intercalation of the cell becomes saturated, and cell balancing is continuously performed. S5. After the charging current drops to the cutoff current threshold, the fast charging pile cuts off the power output, and the thermal management module shuts down after a delay in heat dissipation. The time required to charge the battery from 10% SOC to 90% SOC is controlled within 5 to 10 minutes.

[0008] In one embodiment, S1, the fast charging station and the battery complete a communication handshake and verify the battery charging access conditions, specifically including: The active balancing BMS uploads multi-dimensional status parameters of each individual cell to the microprocessor control unit. The microprocessor control unit pre-stores a parameter threshold matrix adapted to the 200A current 3C fast charging condition and verifies the multi-dimensional status parameters item by item according to the parameter threshold matrix. The 3C power fast charging process is executed only if all state parameters meet the 3C fast charging parameter threshold constraints. If any status parameter does not meet the 3C fast charging parameter threshold constraint, the microprocessor control unit will block the high-power output path of the fast charging pile, maintain the charging circuit conduction, and switch to the current slow charging mode adapted to the current battery status.

[0009] In one embodiment, the active balancing of the battery cells to eliminate cell polarization and initial voltage difference specifically involves: The active balancing BMS and the fast charging pile microprocessor control unit continuously interact in real time, collecting the voltage sampling values ​​of all individual cells cycle by cycle during the pre-charging cycle and calculating the real-time individual cell voltage difference; When the voltage difference reaches the preset start-up threshold, the bidirectional energy transfer balancing circuit of the corresponding cell branch is dynamically switched. Under the state of continuous conduction of the pre-charge charging path, cross-cell energy transfer and allocation are performed synchronously, and the active balancing BMS uploads the balancing circuit switching status to the microprocessor control unit in real time.

[0010] In one embodiment, the charging process involves simultaneous execution of a three-layer linkage control, specifically including: The first layer of differential pressure equalization linkage control: The active equalization BMS periodically collects the voltage of each individual cell, selectively switches the bidirectional energy transfer equalization circuit of the corresponding cell branch according to the voltage difference of the individual cells, and uploads the equalization circuit switching information and real-time individual cell differential pressure data to the microprocessor control unit. The second layer of temperature and current linkage control: The active equalization BMS collects the temperature signal of each individual cell, generates a current adjustment command and sends it to the microprocessor control unit, and synchronously outputs the speed adjustment signal to the thermal management module. The third-layer power topology phase-shift control: The microprocessor control unit receives feedback data uploaded from the first and second layers, and outputs a multi-path drive signal with a fixed phase offset to drive each branch of the three-phase interleaved parallel BUCK buck converter to conduct alternately. The microprocessor control unit dynamically corrects the total output power of the three-phase interleaved parallel BUCK buck converter based on the aforementioned two types of feedback data.

[0011] In one embodiment, S4, the charging current naturally decays as the cell becomes saturated with lithium intercalation, and cell balancing is continuously performed. Specifically, the microprocessor control unit acquires the total circuit current sampling signal at a preset sampling period and stores the real-time current sampling value in a register to complete real-time monitoring. The fast charging pile output voltage is locked and unchanged by the closed-loop voltage regulation loop. As lithium ions continue to be intercalated into the active material of the cell, the open circuit voltage of each cell rises synchronously, the battery pack terminal voltage approaches the fast charging pile output clamping voltage, the circuit voltage difference continues to narrow, and the circuit drive current gradually decreases accordingly. During the complete constant voltage charging period with real-time current reduction, the active balancing BMS continuously collects the voltage of each cell and continuously performs bidirectional energy transfer balancing operations across cells.

[0012] In one embodiment, the 3C-level high-rate fast charging method for electric bicycles further includes: The microprocessor control unit collects the current decay rate during the constant voltage stage in real time, constructs the current gradient change characteristic quantity, and classifies and marks the lithium intercalation saturation state of the battery according to the degree of current gradient decay. The active balancing BMS synchronously records and latches the single-cell balancing configuration parameters corresponding to each gradient interval, so that the energy transfer rhythm of the cell matches the real-time current decay gradient. The microprocessor control unit combines the real-time current decay gradient and the individual unit equalization completion to predict the charging cutoff point in advance and send a heat dissipation pre-start signal to the thermal management module in advance, so that the thermal management module enters a low-speed preheating standby state before the charging circuit is completely disconnected. When the loop current reaches the cutoff current threshold, the microprocessor control unit synchronously completes the linkage timing control of power output cutoff, orderly shutdown of the equalization loop, and heat dissipation delay solidification shutdown.

[0013] On the other hand, this application also proposes a 3C-level high-rate fast charging system for electric bicycles, the system including a fast charging pile body and a 48V 30Ah fast charging battery pack matched with the fast charging pile body, the fast charging pile body being connected to a 220V AC mains input; the system also includes: The fast charging pile body includes a bidirectional interleaved PFC rectifier unit, a three-phase interleaved parallel BUCK step-down converter, and a microprocessor control unit; The bidirectional interleaved PFC rectifier unit is connected to 220V AC power at its input end and to the DC bus of the three-phase interleaved parallel BUCK step-down converter at its output end. The microprocessor control unit forms a drive control link with the bidirectional interleaved PFC rectifier unit and the three-phase interleaved parallel BUCK buck converter, respectively. The fast-charging battery pack incorporates an active balancing BMS, a cell temperature acquisition circuit, a composite heat dissipation structure, and an independent thermal management module. The active balancing BMS is configured with multiple bidirectional energy transfer balancing branches, and the active balancing BMS establishes a bidirectional communication link with the microprocessor control unit. The microprocessor control unit is pre-loaded with a parameter threshold matrix, current gradient analysis program, three-layer linkage control scheduling program, and charging cutoff prediction timing logic adapted to the 200A3C fast charging condition. The system operates as described in the 3C-level high-rate fast charging method for electric bicycles.

[0014] In one embodiment, the bidirectional interleaved PFC rectifier unit is provided with two Boost power branches with a phase offset of 180°. The two Boost branches share the input filter inductor and the output bus capacitor. The microprocessor control unit outputs complementary interleaved drive signals to control the two branches to conduct in a time-sharing manner. The microprocessor control unit collects the input AC voltage and the input bus current in real time, calculates them, and dynamically corrects the duty cycle of the two PFC branches to adapt to the dynamic input power fluctuation of 200A high-power fast charging and suppress power frequency harmonic pulsation.

[0015] In one embodiment, the three power branches of the three-phase interleaved parallel BUCK buck converter are arranged with their phases staggered by 120°, and each branch is equipped with an independent sampling resistor and current sharing adjustment loop; the microprocessor control unit collects the output current sampling signals of the three branches and performs real-time closed-loop adjustment of the branch current sharing; the microprocessor control unit receives the individual cell voltage difference and cell temperature feedback signals uploaded by the active equalization BMS, and synchronously adjusts the overall output current or output voltage reference value of the three-phase BUCK, realizing the linkage control of power topology and battery status.

[0016] In one embodiment, the active balancing BMS internally includes a voltage sampling multiplexer switch array, a bidirectional DC-DC energy transfer sub-branch, and a non-volatile parameter storage area. The non-volatile storage area is used to store the balancing switching thresholds and transfer current configuration parameters corresponding to different current gradients during the constant voltage stage. The active balancing BMS receives gradient synchronization commands from the microprocessor control unit in real time and retrieves the preset balancing parameters for the corresponding interval for matching and operation. The active balancing BMS is configured with orderly shutdown timing logic for the balancing branches, which shuts down each energy transfer branch in stages during the charging cutoff stage to avoid instantaneous voltage surges caused by synchronous shutdown of the branches.

[0017] The beneficial effects of the embodiments of this application compared with the prior art are: First, this invention relies on the conventional 220V mains power supply architecture of household use, and combines a two-stage power conversion structure of bidirectional interleaved PFC rectification and three-phase interleaved parallel BUCK step-down, breaking through the technical bottleneck of low charging power and slow charging speed of traditional electric bicycles. It can achieve 3C ultra-high rate charging of batteries, and accurately control the fast charging time of batteries from 10% SOC to 90% SOC within 5 to 10 minutes. Compared with traditional slow charging and 1C conventional fast charging, it greatly improves charging efficiency, meets the user's need for rapid energy replenishment, and is suitable for popular civilian use scenarios.

[0018] Secondly, this invention establishes a two-way communication verification mechanism between the fast charging pile and the battery BMS. Through the verification of the battery charging access conditions, it can accurately determine whether the battery status meets the 3C ultra-high rate fast charging requirements, and switch between high-power fast charging and conventional slow charging modes as needed. It strictly conforms to the new national standard mutual recognition and collaboration specifications for electric bicycle charging, avoids safety risks under ultra-high rate charging conditions from the source, and improves charging adaptability and safety.

[0019] Third, this invention, in the entire charging sequence, combines pre-charge active balancing, fast charging three-layer linkage control and constant voltage continuous balancing strategy, which can effectively eliminate the initial voltage difference of the cells and the difference in charging polarization, solve the problems of battery cell consistency degradation and temperature rise runaway under ultra-high rate charging, accurately control the battery state throughout the fast charging process, and take into account both ultra-high charging rate and battery charging stability. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a 3C-level high-rate fast charging system provided in one embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of a 3C-level high-rate fast charging method for electric bicycles, provided as an embodiment of the present invention. Detailed Implementation

[0023] It should be understood that, when used in this application specification and the appended claims, the term includes indicating the presence of the described feature, integral, step, operation, element and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0024] It should also be understood that the terms used in this application specification and the appended claims refer to any combination of one or more of the associated listed items and all possible combinations, and include such combinations.

[0025] Example 1: like Figure 1-2 As shown, this application proposes a 3C-level high-rate fast charging method for electric bicycles, which is applied to a fast charging system powered by 220V AC mains and includes a two-stage power conversion fast charging pile and a matching 48V30Ah fast charging battery. The fast charging station is equipped with a bidirectional interleaved PFC rectifier unit, a three-phase interleaved parallel BUCK buck converter, and a microprocessor control unit. The front-end PFC rectifier unit boosts the 220V AC power to a 400V-420V DC bus, while the rear-end interleaved parallel BUCK buck converter reduces the bus voltage to 48V DC output. The matching fast charging battery is a 48V 30Ah lithium-ion battery pack, using 3C high-rate cells with an internal resistance as low as 0.8mΩ. A specially designed thin heat dissipation structure reduces charging temperature rise, and an integrated active balancing BMS and thermal management module are incorporated. During charging, the fast charging station and battery complete a handshake through a mutual recognition and coordination protocol. Based on the voltage and temperature information fed back by the BMS, it charges at a constant current of 200A at an ultra-high rate within the 0% to 90% charge range. Charging from 10% to 90% takes only 5-10 minutes, and a full charge from 10% to 100% takes 10-20 minutes. The battery temperature rise throughout the process does not exceed 8°C, achieving safe and fast charging.

[0026] The system of the present invention consists of two core parts: a fast charging pile subsystem and a fast charging battery subsystem. The fast charging pile and the fast charging battery are physically connected through the power transmission line and signal line of the charging gun.

[0027] 1. Components of the fast charging station subsystem and their connections.

[0028] The fast charging station system is installed inside the charging station enclosure, and its specific components are as follows: (1) Pre-stage PFC rectifier unit ( Figure 1 -Element ①): The input terminal connects to a standard 220V household AC power supply, and the output terminal connects to the DC bus. It adopts a bidirectional interleaved PFC topology, integrating two interleaved parallel boost converters, electrically connected to the live and neutral wires of the input AC power supply. The PFC rectifier unit rectifies and boosts the 220V AC power to a stable 400V-420V DC bus voltage, while simultaneously correcting the power factor to above 0.99, reducing harmonic pollution to the power grid.

[0029] (2) The subsequent interleaved parallel BUCK type buck converter unit ( Figure 1-Element ②): Connected between the DC bus output and the charging output port. It adopts a multi-phase interleaved parallel BUCK topology, integrating three parallel BUCK converters. Each converter includes a high-frequency power switch, a freewheeling diode, and an energy storage inductor. The three converters work together with a control timing that is staggered by 120° phase angles. Under microprocessor control, this unit steps down the 400V-420V bus voltage to 48V DC, outputting a 200A high current to the battery pack. The three-phase interleaved parallel structure increases the output current ripple frequency to three times the switching frequency, significantly reducing the demand for output filter capacitors. Simultaneously, it evenly distributes the losses of each power switch across multiple devices, reducing the thermal stress on individual devices and improving the system's thermal management capabilities.

[0030] (3) DC bus capacitor ( Figure 1 -Element ③): Connected between the positive and negative terminals of the output of the front-stage PFC rectifier unit, the input terminal is electrically connected to the output terminal of the PFC rectifier unit, and the output terminal is electrically connected to the input terminal of the subsequent interleaved parallel BUCK type buck converter unit. It is used for voltage regulation, energy storage and filtering of DC bus ripple.

[0031] (4) Current detection unit ( Figure 1 -Element ④): Connected in series in the fast charging pile output circuit, the input terminal is electrically connected to the output terminal of the BUCK step-down transformer, the output terminal is electrically connected to the charging output port, and the current sampling signal output terminal is electrically connected to the current sampling input terminal of the microprocessor control unit. It is used to collect charging current information in real time and adjust the pulse width with a precision ΔI under the control of the microprocessor.

[0032] (5) Voltage detection unit ( Figure 1 -Element ⑤): Connected across the positive and negative terminals of the fast charging pile output port, with the input terminal electrically connected to the charging output port and the voltage sampling signal output terminal electrically connected to the microprocessor voltage signal input terminal. It is used to collect output voltage information in real time and simultaneously detect abnormal states of the charging voltage circuit.

[0033] (6) Charging output port ( Figure 1 -Element ⑥): Located at the front of the charging gun, it integrates two high-current power transmission pins (positive and negative) and four communication signal pins (compliant with the national standard lithium-ion battery 2+4 interface). The socket body has an embedded temperature sensor that is electrically connected to the microprocessor temperature signal input terminal for physically connecting the fast-charging battery and collecting the interface temperature in real time.

[0034] (7) Microprocessor control unit ( Figure 1-Element ⑦): It adopts a high-performance 32-bit ARM Cortex-M series microcontroller chip, which is electrically connected to the current detection unit, voltage detection unit, temperature sensor, PFC rectifier unit control terminal, and buck converter control terminal, and integrates power drive control logic; it has a built-in mutual recognition and collaborative handshake protocol stack and BMS communication decoding module, and communicates with the battery BMS via CAN bus through the communication signal pin of the charging output port (compliant with GB / T27930-2023 standard).

[0035] 2. Components of the fast-charging battery subsystem and their connections.

[0036] The fast-charging battery subsystem is installed inside the battery pack housing, and its specific components are as follows: (1) High-rate battery cell packs ( Figure 1 -Element ⑧): It consists of 16 high-rate lithium iron phosphate cells with a single cell capacity of 30Ah and a nominal voltage of 3.2V connected in series, with a total nominal voltage of 51.2V; each cell adopts a full tab structure design, with the positive tab and negative tab distributed at the top and bottom of the cell, and the cells are electrically connected in series through connecting pieces; air gaps are left between the cells for heat dissipation.

[0037] (2) Thin heat dissipation structure of the shell ( Figure 1 -Element ⑨): Composed of an aluminum alloy thermally conductive skeleton and a phase change composite material. The thermally conductive skeleton covers the outside of the battery cell assembly and makes thermal contact with the surface of each battery cell. The phase change composite material is filled between the shell and the thermally conductive skeleton to uniformly conduct the heat generated during the charging process of the battery cell to the surface of the shell for heat dissipation.

[0038] (3) Active Balancing BMS Module ( Figure 1 -Element ⑩): Installed on the side of the cell assembly, it integrates a voltage acquisition unit, a temperature acquisition unit, an equalization control unit, and a communication unit. It is electrically connected to the positive and negative terminals of each cell through sampling lines. The input terminal of the voltage acquisition unit is electrically connected to the two poles of each individual cell to monitor the real-time voltage of each cell. The input terminal of the temperature acquisition unit is electrically connected to the temperature sensor attached to the surface of each cell to monitor the real-time temperature of each cell. The output terminal of the equalization control unit is electrically connected to the two ends of the individual cells in the cell assembly that need to be equalized, and is used to perform online equalization of cells with high voltage through active discharge or energy transfer during charging. The communication unit communicates with the fast charging pile microprocessor via the communication signal pin of the charging input port through the CAN bus, reporting the real-time status of the battery to the fast charging pile and receiving charging commands.

[0039] (4) Battery charging input port Installed on the side of the battery pack casing, it integrates two high-current power sockets and four communication signal sockets that are consistent with the national standard lithium-ion battery interface. Temperature sensors are embedded in the sockets and are electrically connected to the input terminal of the temperature acquisition unit of the active balancing BMS module.

[0040] (5) Thermal management module unit ( Figure 1 -element ): Integrated inside the battery pack housing, consisting of a cooling fan and a heat-conducting air duct. The air inlet of the air duct faces the outside of the battery pack, and the air outlet faces the air gap between the battery cells. The cooling fan is electrically connected to the control output terminal of the active balancing BMS module.

[0041] In this embodiment, the 3C-level high-rate fast charging method for electric bicycles specifically includes: S1. The fast charging station and the battery complete a communication handshake and verify the battery charging access conditions. Only after the verification is passed will 3C power fast charging be started. S2. When the battery SOC ≤ 10%, it is pre-charged with a current of 3A and the cells are actively balanced simultaneously to eliminate cell polarization and initial voltage difference. S3. When the battery SOC reaches 10% and the cell temperature is below the safe temperature threshold, the fast charging pile outputs a constant current of 200A to achieve 3C rate charging. During the charging process, three-layer linkage control is executed simultaneously. The three-layer linkage control includes differential pressure equalization linkage control, temperature and current linkage control, and power topology phase reversal control. S4. After the SOC reaches 90%, the constant voltage charging mode is switched. The charging current naturally decreases as the lithium intercalation of the cell becomes saturated, and cell balancing is continuously performed. S5. After the charging current drops to the cutoff current threshold, the fast charging pile cuts off the power output, and the thermal management module shuts down after a delay in heat dissipation. The time required to charge the battery from 10% SOC to 90% SOC is controlled within 5 to 10 minutes.

[0042] This embodiment significantly improves the charging rate of electric bicycles and extends battery cycle life by using handshake access verification, pre-charge equalization, 200A high-current constant 3C rate charging, combined with three-layer linkage control of voltage difference equalization, temperature, current and power topology phase misalignment, constant voltage decay and thermal management linkage shutdown throughout the entire process. Under the premise of effectively eliminating cell polarization and ensuring cell consistency and thermal safety, it can effectively eliminate cell polarization and ensure cell consistency and thermal safety.

[0043] In one embodiment, S1, the fast charging station and the battery complete a communication handshake and verify the battery charging access conditions, specifically including: After the fast charging station subsystem physically connects to the battery charging input port of the fast charging battery subsystem via the charging output port, the microprocessor control unit inside the fast charging station system and the active balancing BMS module inside the fast charging battery subsystem establish a communication link via the CAN bus to complete the communication handshake. Subsequently, the active balancing BMS module collects multi-dimensional status parameters such as voltage, temperature, internal resistance, and SOC of each individual cell in the cell group in real time, and generates data messages from these multi-dimensional status parameters, which are periodically uploaded to the microprocessor control unit through the communication interface. The active balancing BMS uploads multi-dimensional status parameters of each individual cell to the microprocessor control unit. The microprocessor control unit pre-stores a parameter threshold matrix adapted to the 200A current 3C fast charging condition and verifies the multi-dimensional status parameters item by item according to the parameter threshold matrix. The 3C fast charging process is executed only when all state parameters meet the 3C fast charging parameter threshold constraints. At this time, the microprocessor control unit removes the power output shielding of the subsequent interleaved parallel BUCK buck converter, generates a PWM drive signal according to the preset 3C fast charging strategy, controls the BUCK buck converter to start the high-power output path, and formally executes the subsequent 3C fast charging process.

[0044] If any state parameter fails to meet the 3C fast charging parameter threshold constraint, the microprocessor control unit will block the high-power output path of the fast charging pile, maintain the charging circuit conduction, and switch to a slow charging mode adapted to the current battery state. Specifically, the microprocessor control unit will execute a safety protection interrupt, immediately blocking the high-power output path of the fast charging pile, forcibly limiting the PWM drive duty cycle of the subsequent BUCK buck converter to a low level, or cutting off the main power switch. However, at the same time, the microprocessor control unit will maintain the basic conduction state of the charging circuit, such as maintaining trickle or low-current reference conduction, and dynamically adjust the control strategy, actively switching the charging mode to a low-rate current slow charging mode adapted to the current battery state, to protect and repair the battery in abnormal condition, until the fast charging conditions are met in the next state detection cycle.

[0045] In one embodiment, the active balancing of the battery cells to eliminate cell polarization and initial voltage difference specifically involves: The active balancing BMS and the fast charging pile microprocessor control unit continuously interact in real time, collecting the voltage sampling values ​​of all individual cells cycle by cycle during the pre-charging cycle and calculating the real-time individual cell voltage difference; When the voltage difference reaches the preset start-up threshold, the bidirectional energy transfer balancing circuit of the corresponding cell branch is dynamically switched. Under the state of continuous conduction of the pre-charge charging path, cross-cell energy transfer and allocation are performed synchronously, and the active balancing BMS uploads the balancing circuit switching status to the microprocessor control unit in real time.

[0046] Specifically, the control processes include the following: During the pre-charging phase, the microprocessor control unit within the fast charging station subsystem maintains continuous CAN bus data interaction with the active balancing BMS module within the battery subsystem. The active balancing BMS module, according to a set sampling period (milliseconds), uses its built-in voltage acquisition unit to sample the voltage of each of the 16 individual cells connected in series in the cell assembly, obtaining the real-time voltage sample values ​​V1 to V16 for each individual cell.

[0047] The active equalization BMS module or microprocessor control unit calculates the real-time individual cell voltage difference within the current acquisition period based on the received real-time voltage sample values, which is the difference between the maximum and minimum individual cell voltage values ​​Vmax and Vmin at the current moment, ΔV = Vmax. Vmin. The system compares the calculated real-time voltage difference ΔV with the pre-stored preset equalization start threshold ΔVth in real time.

[0048] When the active balancing BMS module determines that the real-time voltage difference ΔV of the current cycle reaches or exceeds the preset start-up threshold ΔVth, it indicates that there is a significant voltage difference or polarization phenomenon between the cells. At this time, the active balancing BMS module dynamically locks the target cell with a high or low voltage according to the voltage distribution, and sends a control drive signal to the bidirectional energy transfer balancing circuit connected to the corresponding cell branch, such as an inductive or capacitive active balancing topology. This balancing circuit, while the pre-charge path is continuously conducting (i.e., the fast charging pile charges the battery pack with pre-charge current), simultaneously performs energy transfer and allocation between cells: transferring excess power from the high-voltage cells to the low-voltage cells through the balancing circuit, thereby realizing the active redistribution of power between cells, quickly reducing the voltage difference between cells, and effectively eliminating cell polarization and initial voltage difference.

[0049] During the balancing circuit operation, the active balancing BMS module packages and uploads balancing circuit switching status data, including the currently operating balancing circuit number, energy transfer direction, balancing current magnitude, and current cell voltage change trend, to the microprocessor control unit of the fast charging pile in real time via CAN communication signals. Based on this data, the microprocessor control unit can monitor the battery's internal balancing progress in real time, serving as an auxiliary basis for subsequent stage switching and ensuring the battery has optimal consistency before entering a high-current charging and discharging state.

[0050] In one embodiment, the charging process involves simultaneous execution of a three-layer linkage control, specifically including: The first layer of differential voltage balancing linkage control: Throughout the 200A high-current charging process, the active balancing BMS module continuously monitors and collects real-time voltage data of each individual cell in the cell group at a preset acquisition cycle. The active balancing BMS module calculates the voltage difference between all individual cells based on the collected real-time voltage values. When it is determined that the voltage of a certain individual cell deviates from the average voltage to a preset balancing threshold, the active balancing BMS module dynamically generates control commands based on the deviation, selectively switching the bidirectional energy transfer balancing circuit corresponding to that cell branch, and performing cross-cell energy transfer allocation for cells with excessive voltage differences. Simultaneously, the active balancing BMS module packages and uploads the currently switched balancing circuit number, balancing current direction, and real-time individual cell voltage difference data to the microprocessor control unit in real time via the CAN bus, serving as the basis for upper-level strategy adjustments.

[0051] The second layer of temperature-current linkage control: While performing cell balancing, the active balancing BMS module continuously collects the surface temperature signal of each individual cell through its temperature acquisition unit. The active balancing BMS module compares the current temperature data with preset safety temperature thresholds (such as the first and second temperature thresholds) step by step, generating a current regulation command to adjust the output current of the fast charging pile. This current regulation command is sent to the microprocessor control unit for the microprocessor to adjust the output duty cycle. Simultaneously, the active balancing BMS module synchronously outputs a speed adjustment signal to the thermal management module inside the fast charging battery subsystem based on changes in cell temperature, driving the cooling fan to adjust its speed according to the temperature gradient, forming a closed-loop linkage cooling mechanism between temperature and current.

[0052] The third-layer power topology phase-shift control: The microprocessor control unit receives and parses the differential voltage data uploaded from the first layer and the current adjustment commands uploaded from the second layer in real time. Based on the above feedback data, the microprocessor control unit outputs multiple PWM drive signals to the downstream interleaved parallel BUCK step-down converters in the fast charging pile subsystem. These multiple drive signals have a predetermined fixed phase offset, namely the 120° phase angle offset required by the three-phase interleaved parallel topology, controlling the three BUCK converter branches to conduct alternately according to a specific phase-shift sequence. At the same time, the microprocessor control unit uses the equalization state information of the first layer and the temperature and current adjustment commands of the second layer as feedback variables, and substitutes them into the built-in power control algorithm to dynamically correct the total output power of the three-phase interleaved parallel BUCK step-down converters in real time. This ensures that during 200A high-current 3C rate charging, the system can reduce power and control temperature in time when the cell temperature difference increases, and fine-tune the charging strategy when the cell voltage difference deviates, achieving the optimal high-power output of the system within the safety boundary.

[0053] In one embodiment, S4, the charging current naturally decreases as the cell becomes lithium-ionized, and cell balancing is continuously performed, specifically as follows: The microprocessor control unit acquires the total circuit current sampling signal at a preset sampling period and stores the real-time current sampling value in the register to complete real-time monitoring. Specifically, the current detection unit with electrical connection acquires the analog signal of the total circuit current of the charging output circuit in real time, and converts it into a digital real-time current sampling value through the internal analog-to-digital converter (ADC). The sampled value is then stored sequentially in the register array inside the microprocessor to complete the real-time trajectory monitoring of the transition from the high-current charging state to the decay stage.

[0054] The output voltage of the fast charging pile is locked and kept constant by the closed-loop voltage regulation circuit. In other words, the closed-loop voltage regulation circuit inside the microprocessor control unit is activated, locking the output voltage of the fast charging pile's charging output port and maintaining it at a preset constant voltage clamp value. This clamp value usually corresponds to the upper limit voltage of the battery pack at 90% SOC and is no longer actively adjusted with changes in current.

[0055] As lithium ions continuously embed into the active material of the battery cell, the open-circuit voltage of each cell rises synchronously, and the battery pack terminal voltage approaches the fast-charging pile's output clamping voltage. The voltage difference in the circuit continuously narrows, and the circuit drive current gradually decreases accordingly. In other words, under the aforementioned constant-voltage clamping state, as the charging process continues, lithium ions (Li+) are continuously extracted from the positive electrode under the drive of the electric field, pass through the separator, and continuously embed into the lattice of the negative electrode cell's active material—this is the lithium intercalation process. As the embedding sites within the active material are gradually occupied by lithium ions, the impedance and concentration polarization of the lithium intercalation reaction increase, leading to a synchronous rise in the open-circuit voltage (OCV) of each individual cell. With the rise in the cell's open-circuit voltage, the overall terminal voltage of the battery pack gradually approaches the fixed clamping voltage output by the fast-charging pile. As the battery pack terminal voltage continuously approaches the fast-charging pile's output clamping voltage, the effective potential difference in the charging circuit—that is, the difference between the fast-charging pile's output voltage and the battery pack terminal voltage—continuously narrows. According to Ohm's law I=ΔU / R, when the terminal voltage of the battery pack on the load side is pushed up to close to the power supply output voltage, the magnitude of the internal drive current loses the support of the external voltage difference, and the drive current of the circuit gradually decreases accordingly, realizing natural and smooth decay without instruction intervention, thereby avoiding the risk of overcharging of the battery cell caused by continuous impact of large current.

[0056] During the complete constant-voltage charging period, in which the charging current decreases in real time, the active balancing BMS module of the fast-charging battery subsystem does not stop working due to the current decay. During this stage, the active balancing BMS module continuously collects the real-time voltage values ​​of each individual cell at a preset cycle, and performs bidirectional energy transfer balancing operations across cells without interruption, based on the subtle differences in lithium insertion speed and open-circuit voltage of each cell. By transferring excess energy from cells with higher voltage to cells with lower voltage, it effectively compensates for the mismatch in individual charging rates caused by differences in cell internal resistance or manufacturing processes, ensuring that all cells reach a fully charged and consistent final state at the end of the constant-voltage stage.

[0057] In one embodiment, the 3C-level high-rate fast charging method for electric bicycles further includes: The microprocessor control unit collects the current decay rate during the constant voltage phase in real time, constructs a current gradient change characteristic, and classifies the battery's lithium intercalation saturation state according to the degree of current gradient decay. Specifically, in constant voltage charging mode, the microprocessor control unit continuously and in real time collects the circuit current through the current detection unit at a period higher than the conventional sampling frequency, and performs differential operations on the collected time-series current data to construct the current gradient change characteristic of the current period, i.e., the rate of decrease of the current over time, di / dt. The microprocessor control unit has a pre-set multi-level lithium intercalation saturation mapping table for the battery. Based on this mapping table, the real-time current gradient change characteristic is compared, and the current lithium intercalation saturation state of the cell is classified and marked according to the different degrees of current gradient decay, for example, divided into rapid lithium intercalation period, moderate saturation period, and near full charge saturation period.

[0058] With the synchronized action of current gradient division and grading marking, the active balancing BMS module and the microprocessor control unit maintain high-frequency bidirectional communication. The active balancing BMS synchronously records and latches the individual cell balancing configuration parameters corresponding to each gradient interval, so that the energy transfer rhythm of the cell matches the real-time current decay gradient. This step ensures that under different operating conditions of gradual current decay during the constant voltage stage, the bidirectional energy transfer rhythm between cells can dynamically match the real-time current decay gradient, avoiding overcharging or undercharging of the cells at the end of a full charge due to excessive or insufficient balancing current.

[0059] The microprocessor control unit combines real-time current decay gradients with the individual cell equalization completion rate to predict the charging cutoff point in advance and sends a pre-start signal for heat dissipation to the thermal management module. This allows the thermal management module to enter a low-speed preheating standby state before the charging circuit is completely disconnected. In other words, the microprocessor control unit performs a weighted fusion calculation using the real-time extracted current gradient change characteristics and the individual cell equalization completion rate (i.e., the progress of each cell in reaching the target voltage) synchronously uploaded by the active equalization BMS module. Based on this fused data, the microprocessor control unit predicts the precise cutoff point of the charging circuit, i.e., the estimated time point when the current cutoff threshold is reached. Before reaching the cutoff point, such as a few seconds before the estimated cutoff, the microprocessor control unit immediately bypasses the conventional judgment logic and sends a pre-start signal for heat dissipation to the thermal management module within the fast-charging battery subsystem. Upon receiving this pre-start signal, the thermal management module does not need to wait for the current to drop to zero; that is, before the high-power output of the charging circuit is completely disconnected, it drives the cooling fan into a low-speed preheating standby state to pre-cool the cells and connecting wires in preparation for the upcoming shutdown heat dissipation.

[0060] When the loop current reaches the cutoff current threshold, the microprocessor control unit synchronously completes the coordinated timing control of power output cutoff, orderly shutdown of the equalization loop, and heat dissipation delay-based shutdown. That is, when the real-time collected loop current eventually reaches the cutoff current threshold Icut set internally by the microprocessor according to the attenuation gradient... When the battery is off, the microprocessor control unit no longer performs a single-path operation, but simultaneously triggers a multi-channel linkage timing control: First, it immediately sets the PWM drive signal of the downstream interleaved parallel BUCK buck converter to zero to cut off the power output of the main power circuit; second, it synchronously sends a balance shutdown command to the active balance BMS module, requiring the orderly shutdown of all bidirectional energy transfer balance circuits in operation; third, it maintains the previously pre-started thermal management module to continue operating, executing the preset delayed heat dissipation solidification shutdown program, that is, the thermal management module operates in a forced air cooling or active heat dissipation mode for a preset delay time, ensuring that the battery cell and system have completely dissipated the residual heat of charging and the temperature has dropped to a safe room temperature before finally issuing the shutdown and power-off command for the thermal management module and the entire system.

[0061] Example 2: This application also proposes a 3C-level high-rate fast charging system for electric bicycles, the system including a fast charging pile body and a 48V 30Ah fast charging battery pack matched with the fast charging pile body, the fast charging pile body being connected to a 220V AC mains input; the system further includes: The fast charging pile body includes a bidirectional interleaved PFC rectifier unit, a three-phase interleaved parallel BUCK step-down converter, and a microprocessor control unit; The bidirectional interleaved PFC rectifier unit is connected to 220V AC power at its input end and to the DC bus of the three-phase interleaved parallel BUCK step-down converter at its output end. The microprocessor control unit forms a drive control link with the bidirectional interleaved PFC rectifier unit and the three-phase interleaved parallel BUCK buck converter, respectively. The fast-charging battery pack incorporates an active balancing BMS, a cell temperature acquisition circuit, a composite heat dissipation structure, and an independent thermal management module. The active balancing BMS is configured with multiple bidirectional energy transfer balancing branches, and the active balancing BMS establishes a bidirectional communication link with the microprocessor control unit. The microprocessor control unit is pre-loaded with a parameter threshold matrix, current gradient analysis program, three-layer linkage control scheduling program, and charging cutoff prediction timing logic adapted to the 200A3C fast charging condition. The system operates as described in the 3C-level high-rate fast charging method for electric bicycles.

[0062] In one embodiment, the bidirectional interleaved PFC rectifier unit is provided with two Boost power branches with a phase offset of 180°. The two Boost branches share the input filter inductor and the output bus capacitor. The microprocessor control unit outputs complementary interleaved drive signals to control the two branches to conduct in a time-sharing manner. The microprocessor control unit collects the input AC voltage and the input bus current in real time, calculates them, and dynamically corrects the duty cycle of the two PFC branches to adapt to the dynamic input power fluctuation of 200A high-power fast charging and suppress power frequency harmonic pulsation.

[0063] In one embodiment, the three power branches of the three-phase interleaved parallel BUCK buck converter are arranged with their phases staggered by 120°, and each branch is equipped with an independent sampling resistor and current sharing adjustment loop; the microprocessor control unit collects the output current sampling signals of the three branches and performs real-time closed-loop adjustment of the branch current sharing; the microprocessor control unit receives the individual cell voltage difference and cell temperature feedback signals uploaded by the active equalization BMS, and synchronously adjusts the overall output current or output voltage reference value of the three-phase BUCK, realizing the linkage control of power topology and battery status.

[0064] In one embodiment, the active balancing BMS internally includes a voltage sampling multiplexer switch array, a bidirectional DC-DC energy transfer sub-branch, and a non-volatile parameter storage area. The non-volatile storage area is used to store the balancing switching thresholds and transfer current configuration parameters corresponding to different current gradients during the constant voltage stage. The active balancing BMS receives gradient synchronization commands from the microprocessor control unit in real time and retrieves the preset balancing parameters for the corresponding interval for matching and operation. The active balancing BMS is configured with orderly shutdown timing logic for the balancing branches, which shuts down each energy transfer branch in stages during the charging cutoff stage to avoid instantaneous voltage surges caused by synchronous shutdown of the branches.

[0065] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A 3C-level high-rate fast charging method for electric bicycles, characterized in that, This invention relates to a fast charging system powered by 220V AC mains, comprising a two-stage power conversion fast charging station and a matching 48V 30Ah fast charging battery. The fast charging station includes a front-stage bidirectional interleaved PFC rectifier unit, a rear-stage three-phase interleaved parallel BUCK buck converter, and a microprocessor control unit. The front-stage bidirectional interleaved PFC rectifier unit boosts the 220V AC power to a 400V-420V DC bus, while the rear-stage three-phase interleaved parallel BUCK buck converter reduces the bus voltage to 48V DC output. The fast charging battery incorporates an active balancing BMS, a composite heat dissipation structure, and an independent thermal management module. The charging method includes: S1. The fast charging station and the battery complete a communication handshake and verify the battery charging access conditions. Only after the verification is passed will 3C power fast charging be started. S2. When the battery SOC ≤ 10%, it is pre-charged with a current of 3A and the cells are actively balanced simultaneously to eliminate cell polarization and initial voltage difference. S3. When the battery SOC reaches 10% and the cell temperature is below the safe temperature threshold, the fast charging pile outputs a constant current of 200A to achieve 3C rate charging. During the charging process, three-layer linkage control is executed simultaneously. The three-layer linkage control includes differential pressure equalization linkage control, temperature and current linkage control, and power topology phase reversal control. S4. After the SOC reaches 90%, the constant voltage charging mode is switched. The charging current naturally decreases as the lithium intercalation of the cell becomes saturated, and cell balancing is continuously performed. S5. After the charging current drops to the cutoff current threshold, the fast charging pile cuts off the power output, and the thermal management module shuts down after a delay in heat dissipation. Among them, the time required to charge the battery from 10% SOC to 90% SOC is controlled within 5 to 10 minutes; The fast charging station completes a communication handshake with the battery and verifies the battery charging access conditions, specifically including: The active balancing BMS uploads multi-dimensional status parameters of each individual cell to the microprocessor control unit. The microprocessor control unit pre-stores a parameter threshold matrix adapted to the 200A current 3C fast charging condition and verifies the multi-dimensional status parameters item by item according to the parameter threshold matrix. The 3C power fast charging process is executed only if all state parameters meet the 3C fast charging parameter threshold constraints. If any state parameter does not reach the 3C fast charging parameter threshold constraint, the microprocessor control unit will block the high-power output path of the fast charging pile, maintain the charging circuit conduction, and switch to the current slow charging mode adapted to the current battery state. The charging process involves simultaneous execution of a three-layer linkage control, specifically including: The first layer of differential pressure equalization linkage control: The active equalization BMS periodically collects the voltage of each individual cell, selectively switches the bidirectional energy transfer equalization circuit of the corresponding cell branch according to the voltage difference of the individual cells, and uploads the equalization circuit switching information and real-time individual cell differential pressure data to the microprocessor control unit. The second layer of temperature and current linkage control: The active equalization BMS collects the temperature signal of each individual cell, generates a current adjustment command and sends it to the microprocessor control unit, and synchronously outputs the speed adjustment signal to the thermal management module. The third-layer power topology phase-shift control: The microprocessor control unit receives feedback data uploaded from the first and second layers, and outputs a multi-path drive signal with a fixed phase offset to drive each branch of the three-phase interleaved parallel BUCK buck converter to conduct alternately. The microprocessor control unit dynamically corrects the total output power of the three-phase interleaved parallel BUCK buck converter based on the aforementioned two types of feedback data.

2. The 3C-level high-rate fast charging method for electric bicycles according to claim 1, characterized in that, The active balancing of the battery cells to eliminate cell polarization and initial voltage difference specifically involves: The active balancing BMS and the fast charging pile microprocessor control unit continuously interact in real time, collecting the voltage sampling values ​​of all individual cells cycle by cycle during the pre-charging cycle and calculating the real-time individual cell voltage difference; When the voltage difference reaches the preset start-up threshold, the bidirectional energy transfer balancing circuit of the corresponding cell branch is dynamically switched. Under the state of continuous conduction of the pre-charge charging path, cross-cell energy transfer and allocation are performed synchronously, and the active balancing BMS uploads the balancing circuit switching status to the microprocessor control unit in real time.

3. The 3C-level high-rate fast charging method for electric bicycles according to claim 2, characterized in that, The charging current naturally decays as the cell becomes saturated with lithium intercalation, and cell balancing is continuously performed. Specifically, the microprocessor control unit acquires the total circuit current sampling signal at a preset sampling period and stores the real-time current sampling value in a register to complete real-time monitoring. The output voltage of the fast charging pile is locked and remains unchanged by the closed-loop voltage regulation loop. As lithium ions continue to intercalate into the active material of the cell, the open-circuit voltage of each cell rises synchronously, the voltage at the battery pack terminal approaches the output clamping voltage of the fast charging pile, the circuit voltage difference continues to narrow, and the circuit drive current gradually decreases accordingly. During the complete constant voltage charging period with real-time current reduction, the active balancing BMS continuously collects the voltage of each cell and continuously performs bidirectional energy transfer balancing operations across cells.

4. A 3C-level high-rate fast charging method for electric bicycles according to any one of claims 1-3, characterized in that, Also includes: The microprocessor control unit collects the current decay rate during the constant voltage stage in real time, constructs the current gradient change characteristic quantity, and classifies and marks the lithium intercalation saturation state of the battery according to the degree of current gradient decay. The active balancing BMS synchronously records and latches the single-cell balancing configuration parameters corresponding to each gradient interval, so that the energy transfer rhythm of the cell matches the real-time current decay gradient. The microprocessor control unit combines the real-time current decay gradient and the individual unit equalization completion to predict the charging cutoff point in advance and send a heat dissipation pre-start signal to the thermal management module in advance, so that the thermal management module enters a low-speed preheating standby state before the charging circuit is completely disconnected. When the loop current reaches the cutoff current threshold, the microprocessor control unit synchronously completes the linkage timing control of power output cutoff, orderly shutdown of the equalization loop, and heat dissipation delay solidification shutdown.

5. A 3C-level high-rate fast charging system for electric bicycles, characterized in that, The system includes a fast charging pile body and a 48V 30Ah fast charging battery pack compatible with the fast charging pile body, wherein the fast charging pile body is connected to a 220V AC power input; the system also includes: The fast charging pile body includes a bidirectional interleaved PFC rectifier unit, a three-phase interleaved parallel BUCK step-down converter, and a microprocessor control unit; The bidirectional interleaved PFC rectifier unit is connected to 220V AC power at its input end and to the DC bus of the three-phase interleaved parallel BUCK step-down converter at its output end. The microprocessor control unit forms a drive control link with the bidirectional interleaved PFC rectifier unit and the three-phase interleaved parallel BUCK buck converter, respectively. The fast-charging battery pack incorporates an active balancing BMS, a cell temperature acquisition circuit, a composite heat dissipation structure, and an independent thermal management module. The active balancing BMS is configured with multiple bidirectional energy transfer balancing branches, and the active balancing BMS establishes a bidirectional communication link with the microprocessor control unit. The microprocessor control unit is pre-configured with a parameter threshold matrix, current gradient analysis program, three-layer linkage control scheduling program, and charging cutoff prediction timing logic adapted to 200A and 3C fast charging conditions. The system operates the 3C-level high-rate fast charging method for electric bicycles as described in any one of claims 1 to 3.

6. A 3C-level high-rate fast charging system for electric bicycles according to claim 5, characterized in that, The bidirectional interleaved PFC rectifier unit is equipped with two Boost power branches with a phase offset of 180°. The two Boost branches share the input filter inductor and the output bus capacitor. The microprocessor control unit outputs complementary interleaved drive signals to control the two branches to conduct in a time-sharing manner. The microprocessor control unit collects the input AC voltage and input bus current in real time and performs calculations to dynamically correct the duty cycle of the two PFC branches, adapting to the dynamic input power fluctuation of 200A high-power fast charging and suppressing power frequency harmonic pulsation.

7. A 3C-level high-rate fast charging system for electric bicycles according to claim 6, characterized in that, The three-phase interleaved parallel BUCK buck converter has three power branches with phases staggered by 120°. Each branch is equipped with an independent sampling resistor and current sharing adjustment loop. The microprocessor control unit collects the output current sampling signals of the three branches and performs real-time closed-loop adjustment of the branch current sharing. The microprocessor control unit receives the individual cell voltage difference and cell temperature feedback signals uploaded by the active equalization BMS and synchronously adjusts the overall output current or output voltage reference value of the three-phase BUCK to realize the linkage control of power topology and battery status.

8. A 3C-level high-rate fast charging system for electric bicycles according to claim 7, characterized in that, The active balancing BMS internally includes a voltage sampling multi-channel selection switch array, a bidirectional DC-DC energy transfer sub-branch, and a non-volatile parameter storage area. The non-volatile storage area is used to store the balancing switching threshold and transfer current configuration parameters corresponding to different current gradients during the constant voltage stage. The active balancing BMS receives gradient synchronization commands from the microprocessor control unit in real time and retrieves the preset balancing parameters for the corresponding interval for matching operation. The active balancing BMS is configured with orderly shutdown timing logic for the balancing branches, which shuts down each energy transfer branch in stages during the charging cutoff stage to avoid instantaneous voltage surges caused by synchronous shutdown of branches.

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