Dual-Cell Supervisor Circuit for Automotive Battery Packs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery management systems face challenges in accurately and efficiently monitoring cell voltages, temperatures, and impedance in multi-cell battery systems due to tradeoffs between single-cell and multi-cell supervisor circuits, including impedance measurement complexity, need for external components, and high IC costs.
Innovation Solution
The use of dual-cell supervisor integrated circuits positioned between adjacent battery cells to monitor differential cell voltages and impedance with minimal external components and power consumption, combining advantages of single-cell and multi-cell supervisors by performing impedance measurements with short local wiring and constant die temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multi-cell supervisor circuits are used to monitor six or more battery cells, then the number of ICs is reduced, but impedance measurement complexity increases due to many long wires between the IC and cells
Solution Approach 1:
The patent divides the monitoring function into segments by placing multiple SCSC ICs at different locations in the battery pack, with each SCSC monitoring a subset of cells. This segmentation reduces the wire length and complexity for impedance measurements compared to a single MCSC IC monitoring all cells, while still reducing the total number of ICs compared to using individual supervisors for each cell.
2Quantity of substance
If multi-cell supervisor circuits are used, then fewer ICs are required, but external temperature sensor components and associated connection wiring are required
Solution Approach 1:
The patent merges the temperature sensing function with the voltage monitoring function by integrating temperature sensors directly into the SCSC ICs. This combination eliminates the need for separate external temperature sensor components and their associated wiring, while still allowing fewer ICs to be used compared to individual cell monitoring approaches.
3Device complexity
If single-cell supervisor circuits are mounted close to each cell, then impedance measurement is simplified, but the number of ICs increases to 100 ICs in a typical automotive application
Solution Approach 1:
The patent segments the battery pack into multiple zones, with SCSC ICs placed at strategic locations to monitor subsets of cells in each zone. This segmentation maintains short wire lengths for impedance measurements within each zone while reducing the total number of ICs needed compared to placing an IC at every single cell.
4Reliability
If single-cell supervisor circuits are used, then each cell can be monitored independently, but IC costs increase significantly
Solution Approach 1:
The patent makes the SCSC ICs universal by designing them to monitor multiple cells (typically 2-6 cells per IC) rather than being dedicated to a single cell. This multi-functionality reduces the total number of ICs required, thereby reducing overall IC costs, while still maintaining independent monitoring capability for each cell through the distributed architecture.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A high-voltage automotive battery pack, system, architecture, and methodology include a first and second adjacent battery cells (410, 420) connected to a dual-cell supervisor circuit (412) that is positioned to bridge the first and second battery cells and that is connected to monitor the first and second battery cells, wherein the dual-cell supervisor circuit comprises current injection and impedance-detection circuitry (510) for separately measuring a voltage, impedance, and temperature at each of the first and second battery cells, alone or in combination with an external switched inductor (501) which is coupled to be switched across the first battery cell (505) or the second battery cell (506) to perform low-loss impedance measurement of the first and second battery cells.