Local Cell Balancing via Switching and Segmentation
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Solution Overview
Problem
Traditional methods for balancing battery cells in high-cell-count batteries are inefficient due to excessive energy dissipation, complex wiring requirements, and scalability issues, limiting overall battery performance.
Innovation Solution
A system with local sensing and switching circuits that dynamically disconnect underperforming cells from the battery module, using cell controllers to monitor parameters and switch cells between active and inactive modes, minimizing connections and optimizing measurement, data sharing, and decision-making processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistor bleed balancing is used to balance battery cells, then cell voltage equality is improved, but energy efficiency deteriorates due to significant energy dissipation as heat in the shunt resistor
Solution Approach 1:
The patent extracts and removes weak cells from the series connection, disconnecting them via switching circuits. This eliminates the need to dissipate energy from strong cells through resistors, as the weak cells are simply taken out of the circuit rather than having their voltage forced down through energy-wasting resistance.
Solution Approach 2:
The battery module is segmented into individual cell groups with independent switching control. Each cell can be independently disconnected, allowing the system to maintain only the necessary number of cells in series connection, thereby avoiding energy dissipation while maintaining voltage balance.
2Loss of energy
If recharge current modulation is used for cell balancing, then energy efficiency is improved, but device complexity worsens due to numerous wire connections required to each cell
Solution Approach 1:
Instead of modulating current through complex wiring to each cell, the patent extracts the problem of cell imbalance by simply disconnecting weak cells via switching circuits. This reduces wiring complexity while maintaining energy efficiency, as the switching circuits require minimal connections compared to full current modulation wiring.
Solution Approach 2:
The battery system is segmented into independently controllable cell groups with local switching circuits. Each cell controller manages its associated cell's connection status, eliminating the need for complex inter-cell wiring while maintaining efficient energy management through localized control decisions.
3Loss of energy
If charge pumping is used for cell balancing, then energy efficiency is improved, but device complexity worsens due to excessive wiring requirements that prevent scaling to high cell count batteries
Solution Approach 1:
The patent removes weak cells from the series connection using simple switching circuits rather than implementing complex charge pumping mechanisms. This extraction approach achieves energy efficiency without the excessive wiring requirements, enabling scalable deployment in high cell count battery systems.
Solution Approach 2:
The battery module is divided into independently switchable cell groups, each with local control. This segmentation allows the system to scale to high cell counts without proportionally increasing wiring complexity, as each cell group is managed independently with minimal interconnection requirements.
4Reliability
If traditional cell balancing methods are used in high cell count batteries, then cell voltage balance is improved, but productivity deteriorates due to limited scalability and increased packaging size
Solution Approach 1:
The battery system is segmented into independently controllable cell groups with local switching circuits and controllers. This segmentation enables linear scaling with cell count, as each cell or cell group can be managed independently, maintaining voltage balance capability while improving productivity and reducing packaging size requirements.
Solution Approach 2:
Weak cells are extracted and disconnected from the series connection, allowing the battery system to operate with only the necessary number of functional cells. This approach maintains voltage balance while improving scalability, as the system can dynamically adjust the number of active cells based on their performance status.
Data Source
AI summary
A system and method for cell balancing within a battery module includes local sensing and switching at each of the battery cells. A switching circuit is associated with each one of the battery cells to connect or functionally disconnected the battery cell from the battery module. A module controller generates one or more parameter threshold values as maximum operating values for each of the battery cells. Each cell has a cell controller associated therewith to monitor one or more cell parameters, which are communicated to a summing module via a shared monitoring line, averaged, and communicated to the module controller. The cell controllers each receive a parameter threshold value via a shared control line and command the associated switching circuit to functionally disconnect and to bypass the battery cell if the cell parameter exceeds the corresponding parameter threshold value. Methods of checking the battery module are also provided.