A lead-acid battery modular management method and system

Abstract

The present application relates to the technical field of lead-acid battery management, and particularly relates to a modular management method and system for lead-acid batteries. The method realizes communication mutual recognition between the battery and the charger, intelligent charging control, state monitoring and safety protection by integrating a battery management module (BMS) in the interior of a lead-acid battery pack. The system comprises an intelligent battery pack and an external charging device, the intelligent battery pack is composed of a common battery pack and an intelligent battery pack integrated with a BMS, and the BMS has functions of voltage, temperature and current acquisition, Bluetooth communication, SOC / SOH calculation, MAP charging control, alarm protection and the like. The present application can meet the requirements of the new national standard for charging mutual recognition, prevent users from privately modifying, improve charging efficiency and safety, prolong battery life, support mobile phone APP and intelligent charging network access, and realize remote monitoring and management.

Description

Technical Field

[0001] This invention relates to the field of lead-acid battery management technology, and in particular to a modular management method and system for lead-acid batteries, applicable to battery management and charging control in fields such as electric bicycles and energy storage systems. Background Technology

[0002] With the popularization of electric bicycles and the development of new energy technologies, lead-acid batteries are widely used in various scenarios due to their low cost and high reliability. However, traditional lead-acid battery packs are mostly non-intelligent designs, lacking effective status monitoring and charging management functions, leading to many problems during use. According to the "Safety Technical Specifications for Electric Bicycles" (GB17761-2024) and its supporting standards, the new national standard, which will be implemented on September 1, 2025, requires that the charger and battery pack have a mutual recognition protocol during charging of lead-acid batteries. This requirement aims to improve charging safety and prevent risks such as overcharging, bulging, and leakage. However, existing lead-acid battery packs cannot achieve communication handshake and mutual recognition with the charger, thus failing to meet the requirements of the new national standard.

[0003] Currently, the conventional solution on the market is to implement charging management and mutual recognition protocols through an external charging management module. While this external module can achieve the functionality to a certain extent, it has significant drawbacks: consumers can easily remove the module later and continue to use a regular charger for blind charging, thus bypassing safety protection and leading to safety hazards such as overcharging, overheating, or even fire. In addition, the external module increases the system's size and cost, and is inconvenient to install, affecting the user experience.

[0004] On the other hand, existing lead-acid batteries lack intelligent management functions, preventing users from monitoring the battery's remaining capacity and health status in real time. Battery aging or insufficient charge can easily lead to vehicle breakdowns, impacting the user experience. While some high-end batteries employ built-in BMS modules, their complex design, high cost, and failure to fully adapt to the characteristics of lead-acid batteries, such as charging curves and temperature sensitivity, result in ineffective management.

[0005] Furthermore, traditional lead-acid battery charging methods are mostly constant current and constant voltage charging, which has low charging efficiency, long charging time, and cannot dynamically adjust charging parameters according to battery status. This not only affects battery life but also increases energy consumption. In scenarios where the battery is depleted or stored for a long time, the battery is prone to entering a deep discharge state, making it difficult to recharge and further shortening battery life.

[0006] Therefore, there is an urgent need in this field for a highly integrated, cost-optimized lead-acid battery solution with intelligent management functions that can meet the requirements of the new national standards, improve battery safety, extend battery life, be compatible with existing charging equipment, and improve user experience. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a modular management method for lead-acid batteries, characterized by comprising the following steps:

[0008] S1: The battery management module (BMS) is integrated inside the lead-acid battery pack. The BMS has functions such as voltage acquisition, temperature acquisition, current acquisition, Bluetooth communication, charging control, SOC calculation, and SOH calculation. The battery pack consists of a regular pack and a smart pack. The smart pack integrates the BMS board inside the battery pack by replacing one of the battery connector PCB mounting boards in the regular pack with the BMS board. The battery pack includes a top cover, which is installed using sealed potting compound.

[0009] S2: The BMS enables a mutual recognition protocol between the battery pack and the charger, and controls the charging process based on real-time collected battery data;

[0010] S3: Charging is achieved using MAP charging logic. Based on the group voltage, battery temperature and SOC value, a preset MAP table is queried, and a request for current and voltage values ​​is sent to the charger to achieve charging.

[0011] S4: The BMS performs alarm protection functions, determines whether overcharge, overtemperature or overcurrent protection is triggered based on real-time data, and controls the charging switch;

[0012] S5: Connects to external devices via Bluetooth to enable data uploading, status monitoring, and remote management.

[0013] Furthermore, in S1, the BMS comprises two parts: BMS hardware and BMS software. The BMS hardware includes an MCU, a data acquisition circuit, and a charge / discharge control circuit. The BMS software functions include data acquisition, alarm protection, charging control, external communication, SOC calculation, and SOH calculation.

[0014] Furthermore, the BMS communicates with a mobile app, smart charger, or fast charging station via Bluetooth.

[0015] Furthermore, the MAP charging logic includes: the BMS queries the MAP table based on the group voltage and temperature, requests the charger to output the corresponding current and voltage, and when the group voltage exceeds the current MAP limit, it enters the next stage request until charging is completed or the protection condition is triggered.

[0016] Furthermore, the alarm protection functions include: when the battery pack voltage is lower than the set value, the charging MOS is turned on by default to prevent the battery from being discharged due to long-term storage; when the voltage recovers, the BMS restarts and continues to execute the charging control logic.

[0017] Furthermore, the SOC calculation uses a shunt to collect the charging and discharging current, and uses the time-integration method to calculate the SOC coulombic charge; the SOH calculation is based on the comparison between the cumulative full-charge capacity and the initial factory capacity to calculate the real-time SOH value.

[0018] Furthermore, the BMS supports counting the number of charging cycles. When the cumulative charge reaches 90% of the rated capacity, the number of cycles is incremented by one, and the data is saved periodically.

[0019] In addition, the present invention also provides a modular management system for lead-acid batteries, including a battery pack and an external charging device. The battery pack integrates a BMS, which includes an MCU, a data acquisition circuit, and a charge / discharge control circuit. The external charging device includes a smart charger and a fast charging station.

[0020] The embodiments of the present invention have the following technical effects:

[0021] This invention achieves intelligent and modular management of lead-acid batteries, meeting the requirements of the new national standard and improving safety, efficiency, and user experience. The main technical benefits are reflected in the following aspects: First, by integrating a BMS and using a modular design, this invention meets the new national standard's requirements for charging interoperability, effectively preventing unauthorized modifications and fundamentally eliminating the safety hazards caused by blind charging. Second, through optimized MAP charging logic, charging efficiency is significantly improved, reducing charging time from the traditional 8 hours to approximately 5 hours, while also reducing battery wear and extending battery life. Third, precise calculation of SOC and SOH allows users to understand the battery status in real time, avoiding breakdowns and improving ease of use. Fourth, Bluetooth communication and intelligent network access functions enable remote monitoring and batch management, providing operators with efficient management tools. Finally, this system is compatible with existing charging equipment, reducing upgrade costs and having broad application prospects. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a system architecture diagram provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of conventional package welding provided in an embodiment of the present invention;

[0025] Figure 3This is a schematic diagram of the BMS board installed inside the battery pack according to an embodiment of the present invention;

[0026] Figure 4 This is an example diagram of MAP charging provided in an embodiment of the present invention;

[0027] Figure 5 This is a flowchart of the MAP charging control logic provided in an embodiment of the present invention;

[0028] Figure 6 This is a BMS power supply and charging control circuit diagram provided in an embodiment of the present invention;

[0029] Figure 7 This is a normal charging control flowchart provided in an embodiment of the present invention;

[0030] Figure 8 This is a diagram illustrating the voltage change process under a power shortage scenario provided in an embodiment of the present invention.

[0031] Figure 9 This is a flowchart of the reverse discharge and downhill scenario control provided in an embodiment of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are part of this invention.

[0033] The modular management method and system for lead-acid batteries of this invention integrates a battery management module (BMS) inside the lead-acid battery pack to achieve intelligent management functions. The prototype image of the intelligent battery pack shows the overall structure of the battery pack, including the ordinary pack and the intelligent pack sections. The intelligent battery pack integrates a BMS board, replacing a single PCB mounting board for the battery connector strip in a traditional battery pack, achieving a compact structure and cost optimization.

[0034] like Figure 1As shown in the diagram, the overall system architecture of the 48V system consists of a standard battery pack and a smart battery pack. The smart battery pack has BMS management functions, enabling voltage, temperature, and current acquisition, Bluetooth handshake communication, charging management, and SOC / SOH calculation. BMS functions include: battery pack voltage acquisition (collecting the pack voltage value Vbat and calculating the average single-cell voltage Vo = Vbat / 24); real-time battery temperature T for MAP charging and over-temperature protection; real-time charging and discharging current I for determining the battery pack's charging and discharging status and for SOC coulomb calculation; Bluetooth communication for mutual recognition handshake protocols between the battery pack and compatible chargers / fast charging stations, as well as intelligent functions such as connecting to a mobile app; charging management with MAP charging capabilities, enabling a certain degree of fast charging for lead-acid battery packs and extending battery cycle life; and SOC / SOH calculation with coulomb calculation similar to lithium batteries, allowing users to monitor remaining battery power in real time, alleviating range anxiety, and prompting users to replace batteries promptly through SOH calculation.

[0035] like Figure 2 The diagram shown illustrates the connection method of a traditional battery pack. A standard battery pack uses two standard battery connector PCB mounting boards, with the positive and negative leads exiting from both ends. The positive lead requires cross-wire soldering.

[0036] The BMS board replaces one PCB mounting board in the standard battery pack (1S routing method - above). The actual installation diagram within the battery pack is shown below. Figure 3 As shown. This replacement method integrates the battery management module inside the battery pack, resulting in a more compact size and optimized cost, while meeting the charging management and interoperability requirements of the new national standard. Furthermore, the use of a sealed potting compound for the battery pack's top cover prevents users from using modifications or jumper wires to achieve blind charging, thus avoiding safety hazards.

[0037] A lead-acid battery management system (BMS) consists of two parts: BMS hardware and BMS software. The hardware part comprises an MCU, data acquisition circuits, and charge / discharge control circuits. The software's main functions include basic data acquisition, alarm and protection, charging control, external communication, and SOC and SOH calculations.

[0038] SOC / SOH calculation uses a shunt to collect charging and discharging currents and employs a time-integration method to calculate the SOC coulombic capacity. A full charge requires setting the value to 100%, and a full discharge requires setting it to zero. When the MCU powers on, it needs to estimate the current SOC based on the lead-acid battery's OCV. The real-time SOH value is calculated by comparing the accumulated capacity during full charging with the initial factory capacity.

[0039] The number of charge cycles is calculated based on the accumulated power consumption calculated over time. When the accumulated value reaches 90% of the rated capacity, the number of charge cycles is incremented by 1, and the accumulated power consumption is reset to zero, starting the next accumulation cycle. The accumulated power consumption value and the number of charge cycles need to be saved every 30 seconds to ensure that when the MCU is powered off and then powered on again, the calculation can continue based on the previously saved data.

[0040] The alarm protection function requires calculation based on real-time sampling data from the BMS and judgment of the corresponding alarm protection of the BMS according to a preset strategy. If protection is triggered, the battery charging function is disabled according to the preset strategy.

[0041] When a battery is charged with a high current, it can be charged quickly, but some charge will not be fully utilized, wasting some of the battery's capacity. Conversely, charging with a low current allows for a larger charge, but takes longer. Traditional lead-acid batteries typically use a constant current + constant voltage charging scheme, with approximately 90% of the state of charge (SOC) achieved in the constant current phase, usually at a continuous 2A / 3A, resulting in an overall charging time of around 8 hours. Compared to traditional charging methods, introducing MAP (Maximum Amount Modulation) charging can improve the charging efficiency of the constant current phase to some extent, reducing the overall charging time to around 5 hours.

[0042] For the MAP request charging function during charging, the BMS, based on real-time collected group voltage, battery temperature, and real-time SOC value, and according to a preset charging MAP table, sends a current request to the charger / fast charging station via Bluetooth communication, thereby achieving efficient and safe charging control. Figure 4 As shown, the MAP example lists the requested current and voltage values ​​at different voltages and temperatures.

[0043] The overall control logic flowchart is as follows: Figure 5 The diagram illustrates the complete process of MAP charging.

[0044] The 48V system consists of 2V / 24S cells connected in series. The BMS (Battery Management System) collects the group voltage value Vbat in real time and calculates the average single-cell voltage value Vo = Vbat / 24, while simultaneously collecting the real-time battery temperature T. Based on the collected group voltage value Vbat and temperature T, the BMS consults a preset MAP (Battery Mapping Table) to determine the current and voltage values ​​that need to be requested from the charger. For example, at the start of charging, the group voltage is 49.32V (equivalent to 2.055V per cell), and the battery temperature is 5℃. According to the MAP, the current requested current / voltage is 8A / 2.06V, which translates to a total group current / voltage of 8A / 49.44V. The charger outputs a constant current of 8A based on the received requested current / voltage value until the BMS detects that the group voltage exceeds the current MAP limit (e.g., 49.44V). Then, the BMS proceeds to the next requested current / voltage value (10A / 50.4V). This process is repeated until the charging process is complete. The charging will end under one of the following conditions: The battery pack voltage reaches the upper limit (e.g., 2.45*24=58.8V), the charger output current is 0, that is, the current in the constant voltage section slowly drops to 0, at which point the SOC is set to 100%; the user unplugs the charger or the charger is disconnected and power is cut off, etc., and the charging ends; due to various objective or internal battery reasons, the battery temperature T exceeds the set upper limit value, the BMS requests the current to be 0, and the charger ends the charging.

[0045] The charging control circuit and logic control framework diagram is as follows: Figure 6 For example. Figure 6 As shown, a 48V battery pack, controller, and charger form a basic charging and discharging circuit. The BMS controls the charging switch of the battery pack through MOSFET Q1, but does not control the discharging. After the 48V battery pack draws power from its terminals, it outputs a VMOS voltage through the voltage regulator circuit VR. This voltage is used to power the MOSFETs and also to supply 3.3V to the MCU and other digital circuits via the subsequent BUCK output. The MCU controls the high and low levels of the FEET-ON / OFF I / O port to turn the Vgs of NMOS Q1 on and off, thus enabling and disabling charging. When the battery pack voltage is higher than 38V, the MCU operates normally, and the BMS determines the charging MOSFET shutdown condition based on various logic and protection mechanisms. When the battery pack voltage is lower than 38V, the BUCK does not operate and does not output 3.3V, the MCU also does not operate, and the charging MOSFET is on by default (the battery will not be left idle for a long time to deplete its charge). The BUCK enable pin EN allows changing the voltage values ​​of R1 and R2 to meet the actual cutoff voltage requirements.

[0046] Normal charging scenario determination: The BMS collects the current to determine the charging and discharging status. As long as the T / V does not meet the upper limit cutoff condition, the charging MOS remains closed until the cutoff condition is met. Then, a request for zero current is sent to the charger. If the situation remains abnormal, the charging MOS is disconnected. This solution can also accommodate the blind charging needs of existing vehicles, allowing users to continue charging the battery with a small current using a blind charger. It also includes overcharge shutdown control logic. The relevant control process is as follows: Figure 7 As shown.

[0047] Scenario of prolonged battery depletion after riding: The rider continues riding until the voltage drops below 40V, at which point the central control and controller cease to function. The bike then remains parked for an extended period (simulating a long-distance ride followed by prolonged storage). The battery pack becomes severely depleted, and the rider eventually decides to recharge and resume riding. Analyzing the entire process, the battery pack voltage discharges from its normal level of around 48V down to the controller's lower operating voltage limit (approximately 40V). Due to lead-acid battery self-discharge and other factors, it enters a prolonged state of depletion until the voltage drops to approximately 6V. At this point, a blind charger (or regulated power supply) is needed to force-charge the battery back to its normal voltage. The entire process is as follows: Figure 8 Illustration. Explanation: 0~T1 segment: The group voltage discharges to 40V and enters a depleted state; T1~T2 segment: The voltage continues to drop below 38V, and the BUCK enable (EN) is turned off (other values ​​can be set by changing the resistor, such as...). Figure 6 (R1 and R2 can be set to different shutdown values), 3.3V is not output, the MCU does not work, and the charging MOS is turned on by default (the battery will not be left to deplete for a long time); T2~T3 segment: when the battery pack voltage rises back to above 42V after charging, the BUCK enable EN is turned on, and 3.3V is output to power the MCU again. The MCU continues to collect real-time data and continues to perform charging control according to the above normal charging scenario, thereby realizing the logic closed loop.

[0048] From a circuit design perspective, in scenarios where the battery voltage is below 38V but above 6V, the MCU is inactive, while the charging MOSFET remains on. In these conditions, both discharging and blind charging can proceed normally without current flowing through the body diode of the charging MOSFET, preventing overheating and prolonged battery depletion. In practical load scenarios, when the battery voltage is below 38V, discharge current cannot be generated (the central control and controller cannot operate). Therefore, there is no issue of the MCU not operating and generating discharge current, leading to prolonged overheating of the charging MOSFET's body diode.

[0049] In the event of reverse discharge after the charging MOS is disconnected: the shunt amplifier circuit, combined with the comparator output interrupt signal to the MCU, controls the MOS to close quickly, ensuring that the MOS does not overheat rapidly.

[0050] Once the battery is fully charged, the charging MOSFET is disconnected, and the system immediately enters a long downhill scenario: If the rider briefly twists the handlebars (the measured instantaneous discharge current is around 5A), as in the reverse discharge scenario described above, the MCU can still quickly close the MOSFET. The control flowchart for the reverse discharge and downhill scenarios is as follows: Figure 9 As shown.

[0051] Bluetooth enables communication and intelligent network access in various scenarios: Battery pack connection to mobile app / mini-program: Through the BMS integrated Bluetooth BLE 5.2, it connects to a dedicated app / mini-program, compatible with iOS and Android systems, allowing users to view battery status in real time. Simultaneously, the app reports data to the platform, which monitors the battery status and promptly issues warnings to users when anomalies are detected, improving system safety. Battery pack connection to fast charging stations: The battery pack can also connect to fast charging stations via Bluetooth. The fast charging station collects the battery's maximum allowable charging voltage and current via Bluetooth to quickly charge the battery, ensuring safety (compared to blind charging). The fast charging process can also be monitored remotely from the backend, enabling operators to achieve remote batch management, centralized monitoring, data statistics, and remote operation and maintenance functions.

[0052] Through the above specific embodiments, this invention achieves intelligent and modular management of lead-acid batteries, meets the requirements of the new national standard, and improves safety, efficiency, and user experience.

[0053] 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 them; although the present invention 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A modular management method for lead-acid batteries, characterized in that, Includes the following steps: S1: The battery management module is integrated inside the lead-acid battery pack. The battery management module has functions such as voltage acquisition, temperature acquisition, current acquisition, Bluetooth communication, charging control, SOC calculation, and SOH calculation. The battery pack consists of a regular pack and a smart pack. The smart pack integrates the battery management module board by replacing one of the battery connector PCB mounting boards in the regular pack. The battery pack includes a top cover, which is installed using sealed potting compound. The regular pack uses two regular battery connector PCB mounting boards, with the positive and negative wires exiting at both ends. S2: The battery management module realizes the mutual recognition protocol between the battery pack and the charger, and controls the charging process based on the real-time collected battery data; S3: Charging is achieved using MAP charging logic. Based on the group voltage, battery temperature and SOC value, a preset MAP table is queried, and a request for current and voltage values ​​is sent to the charger to achieve charging. S4: The battery management module performs an alarm protection function, determines whether overcharge, overtemperature or overcurrent protection is triggered based on real-time data, and controls the charging switch to be turned on or off. S5: Connects the battery pack to external devices via Bluetooth communication to enable data uploading, status monitoring, and remote management.

2. The modular management method for lead-acid batteries according to claim 1, characterized in that, In S1, the battery management module comprises two parts: battery management module hardware and battery management module software. The battery management module hardware includes an MCU, a data acquisition circuit, and a charge / discharge control circuit. The battery management module software functions include data acquisition, alarm protection, charging control, external communication, SOC calculation, and SOH calculation.

3. The modular management method for lead-acid batteries according to claim 1, characterized in that, In step S2, the battery management module communicates with a mobile app, smart charger, or fast charging station via Bluetooth.

4. The modular management method for lead-acid batteries according to claim 1, characterized in that, In S3, the MAP charging logic includes: the battery management module queries the MAP table based on the group voltage and temperature, requests the charger to output the corresponding current and voltage, and when the group voltage exceeds the current MAP limit, it enters the next stage request until charging is completed or the protection condition is triggered.

5. The modular management method for lead-acid batteries according to claim 1, characterized in that, In S4, the alarm protection function includes: when the battery pack voltage is lower than the set value, the charging MOS is turned on by default to prevent the battery from being discharged due to long-term storage; when the voltage recovers, the battery management module restarts and continues to execute the charging control logic.

6. The modular management method for lead-acid batteries according to claim 2, characterized in that, The SOC calculation uses a shunt to collect the charging and discharging current and employs a time-integration method to calculate the SOC coulomb capacity; the SOH calculation is based on a comparison between the cumulative full-charge capacity and the initial factory capacity to calculate the real-time SOH value.

7. The modular management method for lead-acid batteries according to claim 1, characterized in that, The battery management module supports counting the number of charge cycles. When the cumulative charge reaches 90% of the rated capacity, the cycle count is incremented by one, and the data is saved periodically.

8. A modular management system for lead-acid batteries, used to implement the method described in any one of claims 1-7, characterized in that, It includes a battery pack and an external charging device. The battery pack integrates a battery management module, which includes an MCU, a data acquisition circuit, and a charge / discharge control circuit. The external charging device includes a smart charger and a fast charging station.

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