Multi-Level Battery Pack Switching for Weak Cell Isolation
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Solution Overview
Problem
Battery packs in electric vehicles are inefficient due to their fixed structure, which is affected by weak or fully charged cells, leading to premature failure and increased waste and costs, as the performance is dependent on the weakest cells, and current control methods primarily focus on safety rather than optimizing energy use.
Innovation Solution
A multi-level power cell pack switching circuitry that allows reconfiguration of power cells based on performance parameters like current, voltage, and state of charge, enabling dynamic connection and disconnection of cells in series or parallel to optimize performance and extend battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed battery pack structure with series-connected cells is used, then the voltage range is sufficient for motor operation, but the pack performance is limited by the weakest cell and cannot be dynamically optimized
Solution Approach 1:
The battery pack structure is transformed from fixed to dynamic through the introduction of switching circuitry. The patent implements a multi-level switching architecture where cells can be reconfigured between series and parallel connections based on real-time operational conditions, allowing the system to adapt its configuration dynamically rather than being locked into a predetermined arrangement
Solution Approach 2:
The battery pack is divided into modular cell groups that can be independently controlled and reconfigured. The switching circuitry segments the battery into manageable units that can be selectively connected in different configurations, enabling independent optimization of each segment based on its state of charge and health
2Reliability
If redundant cells are added to compensate for weak cells, then the motor needs are better supported, but the material cost and pack capacity increase by more than 60%
Solution Approach 1:
The patent changes the operational parameters of existing cells by dynamically altering their connection configuration. Instead of adding more cells, the system changes how existing cells are connected (series vs. parallel) to match the motor's instantaneous power and torque requirements, extracting maximum performance from the available cell inventory
3Object-affected harmful factors
If the battery pack is disconnected when a single cell reaches safety limits, then cell safety is protected, but the charging/discharging stops even though most cells are not fully charged
Solution Approach 1:
The battery pack is segmented into independently controllable cell groups with individual switching circuitry for each cell. This segmentation allows the system to isolate and protect only the specific cell that has reached safety limits while keeping other healthy cells active and contributing to power delivery
Solution Approach 2:
The problematic cell is extracted from the active circuit through the switching mechanism, removing it from the series chain when it reaches voltage or temperature limits. This extraction allows the remaining cells to continue operating without being constrained by the safety limits of a single degraded cell
4Power
If dozens of cells are connected in series to support high voltage and current, then the motor power needs are met, but the internal impedance and degradation are affected by ambient temperature and load current
Solution Approach 1:
The patent implements dynamic reconfiguration of cell connections based on real-time monitoring of temperature, current, and voltage parameters. The switching circuitry adjusts the series/parallel configuration to maintain optimal internal impedance characteristics under varying thermal and electrical load conditions
Data Source
AI summary
A multi-level power cell pack switching circuitry having a plurality of first level cell circuits, and additional plurality of cell circuits of consecutively progressing levels, with switching and control configured to facilitate dynamically changing serial and/or parallel connections between cells and cell circuits.