Fuel Cell Stack Reconfiguration for Degradation Isolation

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Solution Overview

Problem

In solid oxide fuel cell (SOFC) systems, connecting stacks in series or parallel leads to unbalanced current flow and accelerated degradation, reducing system durability and lifespan, and existing solutions require complex power conditioning systems or only bypass degraded stacks without reusing them.

Innovation Solution

An apparatus and method using cheap electric switches to connect fuel cell stacks in series, parallel, or series-parallel configurations, detecting degraded stacks, and rearranging them with normal stacks to prevent performance reduction, improve durability, and extend lifespan by reusing degraded stacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If fuel cell stacks are connected in parallel to increase system capacity, then the system can generate more power, but degradation propagates from degraded stacks to normal stacks, reducing system durability and lifespan

Engineering Contradiction:
Improvesystem capacityVSAvoidsystem durability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The system divides stacks into separate series groups that can be independently managed. Each group is controlled by its own power conditioning system, allowing degraded stacks to be isolated within their group without affecting other groups. This segmentation prevents degradation propagation while maintaining overall system capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically reconfigures stack connections between series and parallel arrangements based on stack health status. When degradation is detected, the system automatically adjusts the connection topology to isolate degraded stacks from normal ones, preventing further degradation propagation while optimizing power output.

Inventive Principle:
Principle #15Dynamics

2Reliability

If each stack is equipped with a separate power conditioning system to independently control current and voltage, then degradation propagation is prevented, but the system construction becomes complicated and production cost increases

Engineering Contradiction:
Improvedegradation preventionVSAvoidsystem construction
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A single power conditioning system performs multiple functions by managing both series and parallel connections of stacks. The system can dynamically reconfigure stack arrangements and control current distribution across different groups, eliminating the need for separate power conditioning systems for each stack while preventing degradation propagation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses dynamic reconfiguration of stack connections to achieve isolation of degraded stacks without requiring complex individual control systems. By automatically adjusting the electrical topology based on stack health, the system prevents degradation propagation using a simplified control architecture.

Inventive Principle:
Principle #15Dynamics

3Reliability

If degraded stacks are bypassed to prevent degradation propagation, then system durability is improved, but the degraded stacks cannot be reused, reducing system productivity

Engineering Contradiction:
Improvesystem durabilityVSAvoidstack utilization
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically reconfigures stack connections to isolate degraded stacks from normal ones, preventing degradation propagation. Degraded stacks remain in the system but are electrically separated, allowing them to be maintained and potentially reused without compromising the health of normal stacks.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Instead of completely bypassing or discarding degraded stacks, the system isolates them electrically while maintaining their physical presence in the configuration. This allows for potential recovery and reuse of degraded stacks after maintenance, maximizing resource utilization while preventing degradation spread.

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP2846388B1Apparatus and method for controlling fuel cell system
Publication Date: 2017.09.27 SK INNOVATION CO LTD
  • EP2846388B1 patent drawingFigure 1A
  • EP2846388B1 patent drawingFigure 1B
  • EP2846388B1 patent drawingFigure 1C

AI summary

Disclosed herein is an apparatus for controlling a fuel cell system, including: a plurality of stack state detecting units for detecting respective states of a plurality of fuel cell stacks; a switching unit for connecting at least parts of the plurality of fuel cell stacks to each other in series or in parallel; and a control unit for detecting at least one degraded stack based on the states of the stacks detected by the plurality of stack state detecting units, and forming at least one degraded stack unit including the detected at least one degraded stack by controlling the operation of the switching unit, so the apparatus can quickly and easily connect the stacks to each other in series, in parallel or in series-parallel using cheap electric switches instead ofusing a plurality ofpower conditioning system (PCS).