Multi-Pack Battery Charging with Sequential CC and Shared CV
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Solution Overview
Problem
Existing battery systems for electric vehicles are complex, heavy, and costly due to the need for separate dedicated cables and inefficient charging methods, which prolong charging time and complicate fault detection and capacity assessment.
Innovation Solution
A battery system with a charging circuit containing a bidirectional charger and a main processor that sequentially performs constant current (CC) charging and then simultaneous constant voltage (CV) charging across multiple battery packs, using a single bidirectional charger and eliminating the need for dedicated cables, while also enabling efficient discharging and fault/failure monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate dedicated cables and bidirectional chargers are used for each battery pack, then charging capability is improved, but device complexity and weight increase
Solution Approach 1:
A single bidirectional charger is designed to serve multiple battery packs through sequential connection and control. The charger can switch between different battery packs and perform both charging and discharging functions, eliminating the need for separate dedicated chargers for each pack while maintaining full charging capability across all packs.
Solution Approach 2:
Multiple battery packs are connected in series through a single charging circuit rather than requiring separate cables for each pack. The system merges the charging function into one centralized bidirectional charger that can manage multiple packs sequentially, reducing the number of components and simplifying the overall system architecture.
2Manufacturing precision
If sequential CC charging is performed for each battery pack, then charging control precision is improved, but charging time increases
Solution Approach 1:
The charging process is divided into periodic phases: first, sequential constant current (CC) charging is performed for each battery pack to ensure precise control and equalization; then, constant voltage (CV) charging is performed simultaneously for all packs. This periodic switching between sequential and parallel charging modes optimizes both control precision and charging speed.
Solution Approach 2:
Before performing simultaneous CV charging, the system first performs sequential CC charging to bring all battery packs to a standardized state. This preliminary action ensures that all packs are ready for simultaneous charging, preventing imbalances and enabling faster overall charging while maintaining control precision.
3Device complexity
If all CC and CV charging is completed for the first battery pack before charging the second battery pack, then charging control is simplified, but charging time and efficiency deteriorate
Solution Approach 1:
The charging system implements periodic action by first performing sequential CC charging for all battery packs to establish control synchronization, then transitioning to simultaneous CV charging for all packs. This approach maintains simplified control during the CC phase while maximizing efficiency during the CV phase, achieving both control simplicity and high productivity.
Data Source
AI summary
A battery system includes: a charging circuit comprising a bidirectional charger and a main processor; and a plurality of battery packs, wherein each of the plurality of battery packs comprises a battery cell and a battery processor, wherein the main processor is configured to transmit, by using the bidirectional charger, to the battery processor of each of the plurality of battery packs, a charging signal to charge the battery cell of each of the plurality of battery packs, wherein the battery processor is configured to: based on receiving the charging signal, sequentially perform constant current (CC) charging of each of the plurality of battery packs according to a predefined order, and based on the CC charging of the plurality of battery packs being completed, simultaneously perform constant voltage (CV) charging of each of the plurality of battery packs.