Selective Cell Charging for Series Battery Pack Balancing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high power applications like electric vehicles, lithium-ion batteries in series become unbalanced due to heating or physical effects, leading to premature depletion and overcharging dangers, necessitating effective cell balancing for optimal charging and power extraction.
Innovation Solution
A system with a power source, controller, and selective charger that couples the power source to specific battery cells in a series, using multiplexors and current sources to balance charge and prevent overcharging by monitoring voltage and state of charge across cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery cells are arranged in series to provide high voltage for power applications, then the required voltage is achieved, but cell imbalance occurs leading to premature depletion and overcharging dangers
Solution Approach 1:
The patent divides the battery pack into individually addressable cell groups and implements separate charging control for each cell or group. The controller monitors voltage and state of charge for each cell independently and applies charging current selectively to specific cells through multiplexors, enabling granular control to prevent imbalance while maintaining series configuration for high voltage output.
2Ease of manufacture
If all battery cells are charged simultaneously in series, then charging is simple, but cell imbalance prevents maximum charging capacity utilization
Solution Approach 1:
The patent implements dynamic charging control where the system continuously monitors cell voltage and state of charge, and adjusts charging current distribution in real-time. The controller can switch between different charging modes (series charging when cells are balanced, individual cell charging when imbalance is detected) and adjust current magnitude based on cell conditions, maximizing charging capacity while maintaining operational simplicity through automated control.
Solution Approach 2:
The patent introduces multiplexors and current source modules as intermediary components between the power source and battery cells. These intermediaries enable the controller to selectively connect and charge specific cells or cell groups while maintaining the overall series architecture. This intermediary layer provides the flexibility needed for individual cell management without requiring complete system redesign.
3Reliability
If selective cell charging is implemented to balance cells, then cell balance is improved, but system complexity increases with additional components
Solution Approach 1:
The patent designs current source modules and multiplexors that serve multiple functions: they enable selective cell charging for balance, provide voltage monitoring capabilities, support both series and individual charging modes, and can be scaled to different battery pack configurations. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in overall system complexity.
Data Source
AI summary
Described examples include a system having a power source having a first output terminal and a second output terminal and a controller. The system also has a selective charger coupled to the controller, the selective charger configured to couple, in response to instructions from the controller, the first output terminal of the power source to a first node that is configured to be coupled to a first terminal of a selected battery cell of two or more serially coupled battery cells, and couple the second output terminal of the power source to a second node configured to be coupled to a second battery terminal of the selected battery cell.