Parallel Cell Topology with Dedicated Buck-Boost Controllers
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Solution Overview
Problem
Current battery management systems face challenges in accurately measuring state of charge without user-initiated rest periods and require cell balancing, which limits battery lifetime and flexibility in power source design.
Innovation Solution
A power source configuration with cells connected only in parallel, each with a dedicated buck-boost controller, allowing for individual control and isolation of cells, eliminating the need for cell balancing and enabling accurate state of charge measurement without resting the entire power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cells are connected in series to increase voltage output, then power delivery capability is improved, but cell balancing complexity and measurement accuracy deteriorate
Solution Approach 1:
The battery system is segmented into multiple independent parallel cell groups, where each group can be individually controlled and measured. This segmentation allows the system to maintain high voltage output through series connection of parallel groups while enabling independent measurement and control of each group, thus resolving the contradiction between power delivery capability and measurement accuracy.
Solution Approach 2:
A controller is introduced as an intermediary component that manages the charging and discharging of each parallel cell group independently. The controller enables accurate state of charge measurement by controlling the resting state of individual groups and manages power delivery by coordinating the operation of multiple groups, thereby resolving the measurement accuracy issue while maintaining high power capability.
2Reliability
If cell balancing techniques are implemented to equalize state of charge, then battery reliability is improved, but device complexity and manufacturing constraints increase
Solution Approach 1:
The battery system divides cells into separate parallel groups with independent controllers, allowing each group to be managed independently. This segmentation eliminates the need for complex cell-to-cell balancing within series strings, as each parallel group naturally maintains balanced cells through independent control, thus improving reliability while reducing system complexity.
Solution Approach 2:
The system implements preliminary control measures by independently managing each parallel cell group from the outset, preventing cell imbalance from developing in the first place. This preliminary action approach eliminates the need for corrective balancing operations, reducing both device complexity and manufacturing constraints while maintaining high reliability.
3Duration of action of moving object
If multiple cells are connected in series-parallel combinations to extend runtime, then battery capacity is improved, but flexibility in power source design is reduced
Solution Approach 1:
The battery system is organized into multiple parallel cell groups that can be independently controlled. This segmentation provides design flexibility by allowing different numbers of parallel groups to be configured based on specific runtime and power requirements, while each group can be optimized for its specific function. The modular nature enables versatile design configurations without being constrained by fixed series-parallel combinations.
Solution Approach 2:
The system dynamically manages multiple parallel cell groups with independent controllers, allowing flexible allocation of power resources based on real-time demands. This dynamic control enables the system to adapt to varying runtime and power requirements by adjusting the contribution of each parallel group, providing both extended runtime capability and design flexibility.
4Measurement precision
If cells are allowed to rest for open circuit voltage measurement, then state of charge measurement accuracy is improved, but productivity and response time deteriorate
Solution Approach 1:
The battery system divides cells into separate parallel groups that can be independently controlled and measured. This segmentation allows one or more groups to be placed in resting state for accurate open circuit voltage measurement while other groups continue to supply power to the load. Consequently, the system achieves high measurement accuracy without sacrificing productivity, as the measurement process does not require the entire battery system to stop operating.
Solution Approach 2:
The controller acts as an intermediary that manages the resting state of individual cell groups during measurement. It can isolate specific groups for measurement while maintaining power delivery from other groups, enabling accurate state of charge measurement without impacting overall system productivity and response time.
Data Source
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AI summary
A power source with multiple cells connected in parallel to a common node or power supply point. The individual cells within the power source may also have a dedicated controller for each of the individual cells such that the dedicated controllers are connected on a one to one basis with each of the respective individual cells.