Bms-based fast charging end limit current method, system, and computer program product

Abstract

A kind of fast charging end current limiting method based on BMS, comprising: charging the whole package to the first constant current charging upper limit SOC using the first constant current;Define gradient current reduction charging SOC interval=(the first constant current charging upper limit SOC, the second constant current charging lower limit SOC)], the gradient current reduction charging SOC interval is divided into multiple continuous rising SOC subintervals, for the SOC subinterval where the whole package current SOC is located, according to the current charging current, the constant current charging voltage corresponding to the upper limit SOC of the SOC subinterval in the charging CCV table is inquired, if the maximum single battery voltage of the whole package>the constant current charging voltage corresponding to the upper limit SOC of the SOC subinterval in the charging CCV table, then the current charging current is adjusted to the charging current corresponding to the next higher SOC subinterval in the charging CCV table;The whole package is charged to full power using the second constant current.This application realizes the balance between safe charging and fast charging simultaneously.

Description

Technical Field

[0001] This invention relates to the field of BMS control technology, and specifically to a fast charging terminal current limiting method, system, and computer program product based on BMS. Background Technology

[0002] During fast charging, to prevent overcharging due to high current at the charging end before the state of charge (SOC) is allowed, the battery management system (BMS) typically sets a fixed voltage threshold. When the highest single-cell voltage exceeds this threshold, the battery is charged at a certain rate (with a smaller charging current) until it is fully charged. For example, during fast charging, when the highest single-cell voltage is >3.57V, the battery is charged at a current of 0.1C until it is fully charged.

[0003] Existing technologies only fix the voltage point at the end of the charging process, and the current is generally large before the end-of-charge current limiting strategy is triggered during fast charging, resulting in a virtual voltage caused by the large current. When the end-of-charge current limiting strategy is triggered, the charging current is adjusted from a high rate to a low rate, which involves a process of cell depolarization voltage drop, potentially causing excessively long charging times. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a fast charging end-point current limiting method based on a BMS, comprising: When the current SOC of the entire pack is less than the first constant current charging upper limit SOC, the entire pack is charged to the first constant current charging upper limit SOC using the first constant current. Define the gradient current reduction charging SOC interval as (first constant current charging upper limit SOC, second constant current charging lower limit SOC). When the current SOC of the entire package ∈ the gradient current reduction charging SOC interval, the gradient current reduction charging SOC interval is divided into multiple continuously increasing SOC sub-intervals. For the SOC sub-interval in which the current SOC of the entire package is located, the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table is retrieved according to the current charging current. The maximum single-cell voltage of the entire package is compared with the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table. If the maximum single-cell voltage of the entire package is greater than the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table, the current charging current is adjusted to the charging current corresponding to the next higher SOC sub-interval in the charging CCV table. This process is repeated for all SOC sub-intervals until the current SOC of the entire package reaches the second constant current charging lower limit SOC. When the current SOC of the entire pack is greater than the lower limit SOC of the second constant current charging, the entire pack is charged to full capacity using the second constant current.

[0005] Furthermore, if the maximum single-unit voltage of the entire package is less than or equal to the constant current charging voltage corresponding to the upper limit of the SOC sub-interval described in the charging CCV table, then the current charging current will be maintained for charging.

[0006] Furthermore, the gradient current reduction charging module is also used to adjust the current to the charging current corresponding to the next higher SOC sub-interval in the charging CCV table, and only after the current SOC of the entire package equals (the lower limit SOC of the next higher SOC sub-interval + the SOC hysteresis value) does it look up the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table based on the current charging current, and compare the maximum single-cell voltage of the entire package with the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table. Furthermore, (the lower limit SOC of the next higher SOC sub-interval + the SOC hysteresis value) ∈ the next higher SOC sub-interval.

[0007] Furthermore, the first constant current is greater than the second constant current.

[0008] Furthermore, in the charging CCV table, the charging current gradient corresponding to multiple continuously increasing SOC sub-intervals decreases.

[0009] Furthermore, the upper limit of the first constant current charging SOC is between 70% and 80%.

[0010] Furthermore, the second constant current charging lower limit SOC is between 95% and 99%.

[0011] A fast charging terminal current limiting system based on BMS includes: The first constant current charging module is used to charge the entire package to the first constant current charging upper limit SOC when the current SOC of the entire package is less than the first constant current charging upper limit SOC. The gradient current reduction charging module defines the gradient current reduction charging SOC interval as (first constant current charging upper limit SOC, second constant current charging lower limit SOC). When the current SOC of the entire package is within the gradient current reduction charging SOC interval, the gradient current reduction charging SOC interval is divided into multiple continuously increasing SOC sub-intervals. For the SOC sub-interval where the current SOC of the entire package is located, the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table is retrieved according to the current charging current. The maximum single-cell voltage of the entire package is compared with the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table. If the maximum single-cell voltage of the entire package is greater than the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table, the current charging current is adjusted to the charging current corresponding to the next higher SOC sub-interval in the charging CCV table. All SOC sub-intervals are traversed until the current SOC of the entire package reaches the second constant current charging lower limit SOC. The second constant current charging module is used to charge the entire pack to full capacity using the second constant current when the current SOC of the entire pack is greater than the lower limit SOC of the second constant current charging.

[0012] A computer program product includes a computer program / instructions that, when executed by a processor, implement the aforementioned BMS-based fast charging end-current limiting method.

[0013] The beneficial effects of this invention are as follows: 1. By introducing a CCV (constant current charging voltage) dynamically determined based on real-time SOC and charging current as a safety threshold, replacing the traditional fixed voltage threshold, the current limiting trigger condition is matched with the actual electrochemical state of the battery in real time. This effectively overcomes the problem of inaccurate judgment caused by inaccurate SOC estimation or "false voltage" of high current, enabling more timely and accurate identification of overcharge risks. This fundamentally improves the safety margin of the battery in the high SOC region at the end of fast charging, preventing safety hazards such as overcharging and lithium plating.

[0014] 2. This invention divides the high SOC range into multiple sub-ranges and sets progressively decreasing gradient charging currents. When a voltage anomaly is detected, the current is reduced to the next gradient instead of directly to a minimum trickle current. This step-down strategy can maintain a relatively large charging current in higher SOC ranges while ensuring safety, thus significantly reducing the problem of excessively long charging times caused by prematurely entering minimum current charging in traditional methods, achieving an optimal balance between safety and efficiency.

[0015] 3. A stable state switching mechanism was constructed by setting a preset hysteresis interval for the SOC (e.g., triggering at 85% and exiting at 87%) for the state transition of each SOC sub-interval. This design effectively avoids frequent switching of charging strategies caused by slight fluctuations in the BMS's SOC estimation value near the threshold point, ensuring the smoothness of the charging process and the robustness of system control, improving the user experience and reducing the impact on components. Simultaneously, the state progression path after current reduction is clearly defined, ensuring stable operation and eventual fulfillment of conditions after the current reduction action, smoothly entering the next stage of judgment, fundamentally avoiding the problem of the current limiting strategy failing to exit. This guarantees that the charging process can proceed efficiently according to the preset gradient, preventing unnecessary extension of charging time due to strategy rigidity in a low-current state. Attached Figure Description

[0016] Figure 1 This is a system block diagram of the present invention.

[0017] Figure 2 This refers to the charging process in Example 1. Detailed Implementation

[0018] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0019] Glossary BMS (Battery Management System): The intelligent brain of the battery pack. It is an electronic control system responsible for monitoring and managing the battery's operating status. Its main functions include: monitoring the battery's total voltage, total current, temperature, and the voltage of each individual cell in real time; preventing overcharging, over-discharging, overcurrent, short circuits, and overheating to ensure the battery operates within safe limits; calculating SOC (State of Charge) and SOH (State of Health); and communicating with charging equipment to send commands, instructing the charging equipment on the appropriate current and voltage for charging the battery. This invention utilizes the core control strategy executed by the BMS.

[0020] The Constant Current Charge Voltage Map (CCV) is a data table that has been experimentally determined and stored in the Battery Management System (BMS). In this invention, the CCV is compiled from a large amount of data collected through constant current charging tests on target battery samples under controlled laboratory conditions. It establishes the correspondence between State of Charge (SOC), charging current, and battery voltage under constant current charging conditions. By inputting a target SOC (e.g., 85%) and a charging current (e.g., 100A), the table can be consulted to determine the battery voltage at which the battery reaches 85% SOC under that current.

[0021] Example 1 As users increasingly demand faster charging speeds, fast charging at high SOC levels (typically SOC > 70%) in highway service areas and public charging stations has become commonplace. In this process, the Battery Management System (BMS) faces a core dilemma: if the traditional fixed voltage threshold method is used for end-of-charge current limiting, the high current can cause premature current limiting due to voltage spikes, unnecessarily slowing down the charging speed; conversely, if current limiting is delayed, errors in SOC estimation or sudden voltage spikes may lead to overcharging safety risks.

[0022] This invention addresses the pain points mentioned above in practical applications by providing an intelligent solution. It primarily operates at the end of the fast charging process, specifically during the stage when the battery charge is high and electrochemical polarization is significant. The system dynamically adjusts the charging current through real-time decisions by the Battery Management System (BMS), aiming to achieve the following goals: while ensuring absolute battery safety and preventing overcharging, it minimizes charging time in the high SOC range, improving the user's actual charging experience at the end of fast charging and alleviating charging anxiety. The specific implementation of this system will now be described in detail with reference to the accompanying drawings.

[0023] A fast charging terminal current limiting method based on BMS includes: When the current SOC of the entire pack is less than the first constant current charging upper limit SOC, the entire pack is charged to the first constant current charging upper limit SOC using the first constant current. Define the gradient current reduction charging SOC interval as (first constant current charging upper limit SOC, second constant current charging lower limit SOC). When the current SOC of the entire package ∈ the gradient current reduction charging SOC interval, the gradient current reduction charging SOC interval is divided into multiple continuously increasing SOC sub-intervals. For the SOC sub-interval in which the current SOC of the entire package is located, the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table is retrieved according to the current charging current. The maximum single-cell voltage of the entire package is compared with the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table. If the maximum single-cell voltage of the entire package is greater than the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table, the current charging current is adjusted to the charging current corresponding to the next higher SOC sub-interval in the charging CCV table. This process is repeated for all SOC sub-intervals until the current SOC of the entire package reaches the second constant current charging lower limit SOC. When the current SOC of the entire pack is greater than the lower limit SOC of the second constant current charging, the entire pack is charged to full capacity using the second constant current.

[0024] [First constant current charging upper limit SOC, second constant current charging lower limit SOC] means that the gradient current reduction charging SOC range is between the first constant current charging upper limit SOC and the second constant current charging lower limit SOC. The lower limit of the gradient current reduction charging SOC range does not include the first constant current charging upper limit SOC, and the upper limit of the gradient current reduction charging SOC range includes the second constant current charging lower limit SOC.

[0025] The above technical solution fundamentally solves the problem of premature or delayed current limiting triggering caused by a fixed voltage threshold. By introducing SOC sub-ranges and dynamic CCV, the current limiting trigger point is more precise, avoiding premature current reduction due to high current false voltage and preventing overcharging risks caused by delayed current reduction due to inaccurate SOC. Compared to traditional methods that directly and abruptly reduce the current from a high current to a trickle current, gradient current reduction can maintain a relatively large current in a higher SOC range while ensuring safety, thus significantly shortening the charging time in the high SOC stage.

[0026] As a preferred implementation, if the maximum single-unit voltage of the entire package is less than or equal to the constant current charging voltage corresponding to the upper limit of the SOC sub-interval in the charging CCV table, then the current charging current is maintained for charging.

[0027] This ensures that as long as the battery is healthy (normal voltage), the current will be maintained at a relatively high level, rather than being blindly reduced. This is key to achieving fast charging and avoids unnecessary performance loss. It highlights that the control logic of this invention reduces current on demand, rather than reducing current only when necessary, demonstrating the intelligence and adaptability of the algorithm.

[0028] In a preferred implementation, after the current charging current is adjusted to the charging current corresponding to the next higher SOC sub-interval in the charging CCV table, the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table is retrieved based on the current charging current, and the maximum single-cell voltage of the entire package is compared with the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table.

[0029] This is the core design feature to prevent charging oscillations. By setting a hysteresis range, it ensures that after current reduction is triggered near a certain SOC point (such as 85%), the system will not frequently switch between current reduction and recovery states due to minor fluctuations in SOC. This avoids drastic jumps in charging current, which not only protects the battery but also improves the reliability of the charging station and BMS hardware, providing a smoother and more stable charging experience.

[0030] In a preferred implementation, (the lower bound SOC + SOC hysteresis value of the next higher SOC sub-interval) ∈ the next higher SOC sub-interval. This constraint ensures that the hysteresis mechanism is logically consistent and effective. If the hysteresis point falls outside the next interval, the entire state transition logic will become chaotic.

[0031] In a preferred embodiment, the first constant current is greater than the second constant current. The charging current decreases as the state of charge (SOC) increases, which is fundamental to achieving safe fast charging. In a preferred embodiment, the charging current gradient corresponding to multiple continuously increasing SOC sub-intervals decreases in the charging CCV table. The charging CCV table is the fundamental database upon which the algorithm of this invention operates.

[0032] In a preferred embodiment, the upper limit of the first constant current charging state of charge (SOC) is between 70% and 80%, and the lower limit of the second constant current charging state of charge (SOC) is between 95% and 99%. Entering the gradient current reduction too early (e.g., >90%) will slow down charging, while entering it too late (e.g., <70%) is not very meaningful; entering the final trickle charging stage too late (e.g., <95%) is risky, while entering it too early (e.g., >99%) will result in excessively long charging times.

[0033] To better illustrate the technical solution of this invention, refer to... Figure 2 For example, see below: 1. The BMS power-on self-test is fault-free and recognizes the A+ & CC2 signals. The vehicle is in fast charging mode. The A+ & CC2 signals are key signals used to confirm that the vehicle and the DC charging pile are physically connected and ready, thereby starting the fast charging process. A valid CC2 signal confirms that the charging gun is physically connected reliably. A valid A+ signal confirms that the charging pile itself is ready and has provided auxiliary power. 2. Continuously monitor the total system charge (SOC) of the battery pack (BMS BatteryPack SOC) during fast charging. Proceed to the next step when the SOC is greater than 80%. 3. Determine the SOC status at this time. If 80% < BMS BatteryPack SOC ≤ 85%, proceed to step 4; otherwise, skip to step 6. 4. Real-time determination of the maximum cell voltage (BatteryMAXCellVoltage) and corresponding charging current (BMSBatteryPackCurrent) of the entire pack. Based on this state, the dynamic CCV at 85% SOC is retrieved: V85%. This is compared with the maximum voltage of the entire pack, Vmax. If Vmax > V85%, the charging request current (BCL CurrentNeed BMS) is adjusted to the current corresponding to the charging gradient of 85%-90% SOC, and the process jumps to step 5. If Vmax ≤ V85%, the process returns to the previous step. 5. Real-time determination of actual SOC. Once BMS BatteryPack SOC > 87%, exit the process and proceed to step 6. 6. Determine the SOC status at this time. If 85% < BMS BatteryPack SOC ≤ 90%, proceed to step 7; otherwise, skip to step 9. 7. Real-time determination of the maximum battery cell voltage (BatteryMAXCellVoltage) and corresponding charging current (BMSBatteryPackCurrent). Based on this state, the dynamic CCV at 90% SOC is retrieved: V90%. This is compared with the maximum battery cell voltage Vmax. If Vmax > V90%, the charging request current (BCL CurrentNeed BMS) is adjusted to the current corresponding to the 90%-95% SOC charging gradient in the charging CCV table, and the process jumps to step 8. If Vmax ≤ V90%, the process returns to the previous step. 8. Detect the actual SOC in real time. When the BMS BatteryPack SOC > 92%, exit the process and jump to step 9. 9. Determine the current SOC status. If 90% < BMS BatteryPack SOC ≤ 95%, proceed to step 10; otherwise, skip to step 12. 10. Real-time determination of the maximum battery cell voltage (BatteryMAXCellVoltage) and corresponding charging current (BMSBatteryPackCurrent). Based on this state, retrieve the dynamic CCV (V95%) at 95% SOC. Compare this with the maximum battery cell voltage (Vmax). If Vmax > V95%, adjust the charging request current (BCL CurrentNeed BMS) to the current corresponding to the 95%-98% SOC charging gradient and proceed to step 11. If Vmax ≤ V95%, return to the previous step. 11. Real-time determination of actual SOC. Once BMS BatteryPack SOC > 98%, exit the process and proceed to step 14. 12. Determine the SOC status at this time. If 95% < BMS BatteryPack SOC ≤ 98%, proceed to step 13; otherwise, skip to step 14. 13. Real-time determination of the maximum battery cell voltage (BatteryMAXCellVoltage) and corresponding charging current (BMSBatteryPackCurrent). Based on this charging current, retrieve the dynamic CCV at 98% SOC: V98%, and compare it with the maximum battery cell voltage Vmax. If Vmax > V98%, proceed to step 14. If Vmax ≤ V98%, return to the previous step. 14. The vehicle is charged to 100% SOC at a 0.1C rate.

[0034] The safety threshold (V) in this invention 85% V 90%...) is not fixed, but rather obtained from a table based on real-time current, eliminating the influence of false voltage and making the judgment more accurate. Current reduction is done in steps, decreasing to the next current level only at a time, rather than decreasing to 0.1C in one step, maximizing charging speed within a safe range. Simultaneously, the introduction of a hysteresis exit mechanism is a key design feature to prevent the system from repeatedly oscillating near the critical point, ensuring smooth and reliable control. The algorithm does not rely on the absolutely precise value of SOC, but rather corrects charging behavior in real time using the precisely measurable physical quantity of voltage, making it more adaptable.

[0035] Example 2 A fast charging terminal current limiting system based on BMS, reference Figure 1 ,include: When the current SOC of the entire pack is less than the first constant current charging upper limit SOC, the entire pack is charged to the first constant current charging upper limit SOC using the first constant current. Define the gradient current reduction charging SOC interval as (first constant current charging upper limit SOC, second constant current charging lower limit SOC). When the current SOC of the entire package ∈ the gradient current reduction charging SOC interval, the gradient current reduction charging SOC interval is divided into multiple continuously increasing SOC sub-intervals. For the SOC sub-interval in which the current SOC of the entire package is located, the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table is retrieved according to the current charging current. The maximum single-cell voltage of the entire package is compared with the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table. If the maximum single-cell voltage of the entire package is greater than the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table, the current charging current is adjusted to the charging current corresponding to the next higher SOC sub-interval in the charging CCV table. This process is repeated for all SOC sub-intervals until the current SOC of the entire package reaches the second constant current charging lower limit SOC. When the current SOC of the entire pack is greater than the lower limit SOC of the second constant current charging, the entire pack is charged to full capacity using the second constant current.

[0036] Example 3 A computer program product includes a computer program / instructions that, when executed by a processor, implement the BMS-based fast charging end-current limiting method in Embodiment 1.

[0037] The contents not described in detail in this specification are prior art known to those skilled in the art. Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0038] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0039] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0040] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. A fast charging terminal current limiting method based on BMS, characterized in that, include: When the current SOC of the entire pack is less than the first constant current charging upper limit SOC, the entire pack is charged to the first constant current charging upper limit SOC using the first constant current. Define the gradient current reduction charging SOC interval as (first constant current charging upper limit SOC, second constant current charging lower limit SOC). When the current SOC of the entire package ∈ the gradient current reduction charging SOC interval, divide the gradient current reduction charging SOC interval into multiple continuously increasing SOC sub-intervals. For the SOC sub-interval where the current SOC of the entire package is located, look up the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table according to the current charging current. Compare the maximum single-cell voltage of the entire package with the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table. If the maximum single-cell voltage of the entire package ≤ the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table, maintain the current charging current for charging. If the maximum single-cell voltage of the entire package > If the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval described in the charging CCV table is used, then the current charging current is adjusted to the charging current corresponding to the next higher SOC sub-interval in the charging CCV table. This process is repeated for all SOC sub-intervals until the current SOC of the entire pack reaches the second constant current charging lower limit SOC. After the current charging current is adjusted to the charging current corresponding to the next higher SOC sub-interval in the charging CCV table, and the current SOC of the entire pack is equal to (the lower limit SOC of the next higher SOC sub-interval + the SOC hysteresis value), then the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval described in the charging CCV table is retrieved based on the current charging current. The maximum single-cell voltage of the entire pack is then compared with the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval described in the charging CCV table. When the current SOC of the entire pack is greater than the lower limit SOC of the second constant current charging, the entire pack is charged to full capacity using the second constant current.

2. The fast charging terminal current limiting method based on BMS according to claim 1, characterized in that: (The lower limit SOC+SOC hysteresis value of the next higher SOC sub-interval) ∈ the next higher SOC sub-interval.

3. The fast charging terminal current limiting method based on BMS according to claim 1, characterized in that: The first constant current is greater than the second constant current.

4. The fast charging terminal current limiting method based on BMS according to claim 1, characterized in that: In the charging CCV table, the charging current gradients corresponding to multiple continuously increasing SOC sub-intervals decrease.

5. The fast charging terminal current limiting method based on BMS according to claim 1, characterized in that: The first constant current charging upper limit SOC is between 70% and 80%.

6. The fast charging terminal current limiting method based on BMS according to claim 1, characterized in that: The second constant current charging lower limit SOC is between 95% and 99%.

7. A fast charging terminal current limiting system based on BMS, characterized in that, include: The first constant current charging module is used to charge the entire package to the first constant current charging upper limit SOC when the current SOC of the entire package is less than the first constant current charging upper limit SOC. The gradient current reduction charging module defines the gradient current reduction charging SOC interval as [first constant current charging upper limit SOC, second constant current charging lower limit SOC]. When the current SOC of the entire package ∈ the gradient current reduction charging SOC interval, the gradient current reduction charging SOC interval is divided into multiple continuously increasing SOC sub-intervals. For the SOC sub-interval where the current SOC of the entire package is located, the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table is retrieved according to the current charging current. The maximum single-cell voltage of the entire package is compared with the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table. If the maximum single-cell voltage of the entire package is less than or equal to the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table, the current charging current is maintained for charging. If the maximum single-cell voltage of the entire package is less than or equal to the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table, the current charging current is maintained for charging. If the individual cell voltage is greater than the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table, then the current charging current is adjusted to the charging current corresponding to the next higher SOC sub-interval in the charging CCV table. This process is repeated for all SOC sub-intervals until the current SOC of the entire pack reaches the second constant current charging lower limit SOC. After the current charging current is adjusted to the charging current corresponding to the next higher SOC sub-interval in the charging CCV table, the current SOC of the entire pack is calculated as (lower limit SOC of the next higher SOC sub-interval + SOC hysteresis value). Only then is the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table retrieved based on the current charging current. The maximum individual cell voltage of the entire pack is then compared with the constant current charging voltage corresponding to the upper limit SOC of the SOC sub-interval in the charging CCV table. The second constant current charging module is used to charge the entire pack to full capacity using the second constant current when the current SOC of the entire pack is greater than the lower limit SOC of the second constant current charging.

8. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the BMS-based fast charging end current limiting method as described in any one of claims 1 to 6.

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