Galvanically Isolated Cell Pods for Scalable Energy Storage
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Solution Overview
Problem
Existing large-scale energy storage systems face limitations in scalability due to the need for precise voltage matching of batteries when paralleled, which restricts the use of different cell types, ages, and physical types, and renders the entire system unreliable if one cell malfunctions.
Innovation Solution
A scalable energy storage system is achieved by using a power electronics converter to galvanically isolate cells, allowing for the parallelization of different cell types and ages, with a common DC interface that prevents failure propagation and allows for independent operation of each cell, enabling the use of various cell chemistries and types without requiring precise voltage matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If batteries are paralleled to achieve large scale energy storage, then the system capacity increases, but the voltage matching requirement becomes more stringent and system complexity increases
Solution Approach 1:
The system divides the battery array into multiple independent modules, each with its own power electronics interface. This segmentation allows each module to operate independently with its own voltage characteristics, eliminating the need for precise voltage matching across the entire system while enabling scalable capacity expansion.
Solution Approach 2:
Power electronics interfaces are introduced as intermediary components between battery modules and the common DC bus. These intermediaries perform voltage conversion and isolation, allowing battery modules with different voltage characteristics to be connected without direct electrical parallel connection, thus reducing system complexity.
2Quantity of substance
If batteries are paralleled to increase system capacity, then more cells can be added, but the reliability decreases because one malfunctioning cell renders the whole array out of service
Solution Approach 1:
The system architecture segments the battery array into electrically isolated modules, each with independent failure domains. A malfunction in one module does not propagate to other modules, allowing the system to maintain operation with degraded capacity rather than complete failure, thus improving reliability.
Solution Approach 2:
The system dynamically manages module connections and disconnections based on operational status. Healthy modules can be selectively connected to maintain system operation, while faulty modules are isolated without taking down the entire array, enabling adaptive reliability management.
3Reliability
If precise voltage matching is required for paralleled batteries, then system reliability improves, but the adaptability decreases and limits the use of different cell types and ages
Solution Approach 1:
Power electronics interfaces serve as intermediaries that perform voltage conversion between diverse battery modules and the common DC bus. This eliminates the need for direct voltage matching between different cell types, ages, or chemistries, while maintaining reliable electrical connection and enabling heterogeneous module composition.
Solution Approach 2:
The common DC bus and power electronics interface create a universal connection standard that can accommodate various battery module types. The system can universally interface with different cell chemistries, voltages, and configurations through the standardized power electronics interface, enabling multi-functional adaptability.
Data Source
AI summary
An energy storage system includes: a grid tie unit comprising at least one DC/AC converter; and multiple pods connected to the grid tie unit, each pod including: a number of cells; and a power electronics unit, wherein the cells are floating relative to the system and are galvanically isolated therefrom. The multiple pods may be organized into packs, with a pack including a thermal management system.