Battery Cell Balancing via Host-Slave Voltage Synchronization
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Solution Overview
Problem
Battery systems in electric vehicles face degradation due to uneven electrical properties among cells in series or parallel connections, leading to overcharging and over-discharging issues, which reduce safety and lifespan.
Innovation Solution
A battery system with a host control unit and balance slave controllers that perform cell balancing by calculating and adjusting the balance charge capacity, using a communication bus to synchronize operations and ensure balanced voltage across cells, thereby preventing overcharging and extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cells are connected in series or parallel to form battery systems, then the battery system can provide required voltage and capacity, but voltage inconsistency among cells causes overcharging and over-discharging
Solution Approach 1:
The patent implements independent balance control for each cell by introducing separate balance switches (S1-S4) and balance charging circuits for each cell group. This allows localized adjustment of charging current to address voltage inconsistency in specific cells while maintaining overall system operation, thereby preventing overcharging and over-discharging of individual cells.
Solution Approach 2:
The patent dynamically adjusts the balance charging current parameters based on real-time voltage detection of each cell. The control unit compares voltages among cells and modulates the balance switching elements to change the charging current distribution, ensuring each cell receives appropriate current to maintain voltage consistency and prevent extreme charging states.
2Stability of the object's composition
If balancing technology is implemented to reduce voltage difference among cells, then cell consistency is improved, but system complexity increases
Solution Approach 1:
The patent divides the battery system into multiple independently controllable cell groups (first to fourth cells) with dedicated balance control circuits for each group. This segmentation allows simplified control of each subset while achieving overall system balance, reducing the complexity burden compared to a fully centralized approach.
Solution Approach 2:
The balance control unit serves multiple functions: it detects voltages of all cells, compares voltage differences, controls balance switches, and manages the balance charging process. This multi-functionality consolidates control logic into a single unit, reducing the need for multiple independent control circuits and thereby managing system complexity.
Data Source
AI summary
A battery system, a control method of a cell balance procedure and a calculation method of a balance charge capacity are provided. The battery system includes a plurality of battery units, a communication bus and a host control unit. Each battery unit includes a plurality of cells, an isolated charger, a switch array circuit, a balance slave switch and a balance slave controller. The host control unit includes a balance host controller, a balance host switch and a system current measurement unit. When the error between a balance detection voltage calculated by each balance slave controller and the balance detection voltage calculated by the balance host controller is less than a predetermined value, the balance host switch and the corresponding balance slave switches are in conduction and the specified plurality cells of battery system are charged for keeping cell balance purpose.