BMS Charging Mode Control for Parallel Battery Current Protection
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Solution Overview
Problem
Existing battery management systems (BMS) lack a comprehensive charging solution that addresses issues such as overcharging, over-discharging, and damage from circulating currents when multiple BMS units with different voltages or capacities are connected in parallel, and require hardware changes for adjusting maximum charging currents.
Innovation Solution
A charging control method and apparatus for BMS that includes a protection charging mode, high-current charging mode, and float charging mode, with a controllable fuse and semiconductor switches to manage charging currents within specific thresholds, and a microcontroller to switch between modes based on charging states, preventing overcharging and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple BMS units with different voltages or capacities are connected in parallel, then the system can handle diverse charging requirements, but circulating currents cause damage to the BMS units
Solution Approach 1:
The patent applies preliminary action by detecting voltage differences between parallel BMS units before charging begins and pre-adjusting the charging current allocation. The control device calculates the voltage difference and determines compensation currents in advance, preventing circulating currents from causing damage before they can occur during normal operation.
Solution Approach 2:
The patent changes the charging current parameter dynamically based on the charging state and voltage differences. The control device adjusts the charging current allocated to each BMS unit according to its state of charge, voltage level, and capacity, transforming a static current allocation into a dynamic, adaptive parameter that prevents circulating currents while accommodating diverse charging requirements.
2Reliability
If a comprehensive charging solution with multiple protection functions is implemented, then overcharging and damage are prevented, but the system complexity increases
Solution Approach 1:
The patent applies universality by designing a control device that performs multiple functions: detecting charging states, calculating voltage differences, determining charging currents, and protecting against overcharging and circulating currents. This single multi-functional control device replaces what would otherwise require multiple separate protection circuits and control mechanisms, achieving comprehensive protection without proportionally increasing system complexity.
Solution Approach 2:
The patent implements feedback by continuously monitoring the charging state of each BMS unit and using this information to dynamically adjust charging current allocation. The control device receives feedback on voltage, capacity, and charging progress, then modifies its control actions accordingly, creating a closed-loop system that provides reliable protection through intelligent, adaptive control rather than complex hard-wired protection circuits.
3Productivity
If hardware changes are made to adjust maximum charging currents, then charging performance is optimized, but the ease of operation and adaptability decrease
Solution Approach 1:
The patent replaces the mechanical hardware-based current adjustment system with an electronic/software-based control system. Instead of physically changing hardware components to adjust maximum charging currents, the control device uses software algorithms to calculate and enforce current limits based on real-time charging state detection. This substitution allows charging performance optimization through software parameters rather than hardware modifications, significantly improving ease of operation and adaptability.
Data Source
AI summary
The disclosure provides a charging control method and a charging control apparatus for a battery management system. The control method includes: selecting, based on a charging state of the BMS, to enter a corresponding charging mode. The charging mode includes a high-current charging mode, a float charging mode, a stop charging mode, and a protection charging mode. During an initial set time after the BMS starts operating, the BMS operates in the protection charging mode. In the protection charging mode, a battery is charged within a protection charging current threshold. After the initial set time ends, one of the protection charging mode, the high-current charging mode, the float charging mode, and the stop charging mode is selected for entry based on the charging state of the BMS. The disclosure resolves a problem of damage to a plurality of BMSs with different voltages or capacities caused by a relatively high circulating current generated when the BMSs are connected in parallel.