Flow Battery Module Floating to Block Shunt Current Paths

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Solution Overview

Problem

Previous redox flow battery systems suffer from inefficiency and unwanted side reactions due to a shunt current path between adjacent power modules operating at different states of charge, leading to decreased battery performance.

Innovation Solution

A battery management system that electronically floats a power module with a lower charge state by adjusting negative-side switches, preventing flow of electrical current to electrical ground and allowing the module to float at a predetermined voltage range relative to an adjacent power module, thereby removing the shunt current path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If power modules operate at different states of charge, then energy storage capacity is improved, but shunt current paths cause inefficiency and unwanted side reactions

Engineering Contradiction:
Improveenergy storage capacityVSAvoidinefficiency due to shunt current
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

An isolation valve is introduced as an intermediary component in the fluid pathway between power modules operating at different states of charge. This valve selectively blocks the shunt current path through the electrolyte while maintaining operational flexibility, thereby preventing energy loss and unwanted side reactions without compromising energy storage capacity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system applies different operational conditions to different power modules by allowing them to operate at different states of charge simultaneously. The isolation valve enables local control of fluid flow, creating distinct operational zones that optimize both energy storage and efficiency by preventing harmful shunt currents in specific modules

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If power modules operate at different states of charge, then energy storage capacity is improved, but unwanted side reactions occur

Engineering Contradiction:
Improveenergy storage capacityVSAvoidunwanted side reactions
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The isolation valve serves as a mediator that selectively interrupts the electrolyte flow path between power modules with different states of charge, thereby preventing unwanted side reactions while preserving the ability to store energy across multiple modules at different charge levels

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system segments the electrolyte flow paths between different power modules using isolation valves, allowing each module to operate independently at its optimal state of charge without causing harmful interactions or side reactions with adjacent modules

Inventive Principle:
Principle #1Segmentation

3Duration of action of stationary object

If shunt current path is present, then battery operation is continuous, but battery performance decreases

Engineering Contradiction:
Improvecontinuous operationVSAvoidbattery performance
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The isolation valve provides dynamic control over electrolyte flow between power modules, allowing the system to adaptively manage shunt currents while maintaining continuous operation. The valve can be opened or closed based on operational conditions, ensuring both continuous battery operation and high performance by preventing shunt current-related degradation

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution improves the efficiency of flow cell batteries by preventing shunt current paths and reducing unwanted side reactions, allowing for more reliable and extended operation.

Implementation Method 1

Adjusting the second negative-side switch to the open position may cause the second power module to electronically float at a predetermined range of voltages relative to an electronic voltage of the first power module

Methodology Applied
Scientific EffectElectrical floating: Electric Field

Implementation Method 2

A redox flow battery facilitates energy storage using liquid electrolyte solutions. Electrolytes are pumped through redox cells of the flow battery to facilitate conversion between chemical energy and electricity

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Implementation Method 3

the battery system may include an electrolyzer configured to electrolyze an electrolyte solution provided to the second power module

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Data Source

PatentEP4235881A1Redox flow battery with floating power module under imbalanced charge conditions
Publication Date: 2023.08.30 LOCKHEED MARTIN ADVANCED ENERGY STORAGE LLC
  • EP4235881A1 patent drawingFigure 1
  • EP4235881A1 patent drawingFigure 2
  • EP4235881A1 patent drawingFigure 3

AI summary

The present disclosure is directed, in certain embodiments, to a flow cell battery system (100). A battery management system (114) detects that a first power module (202a) and a second power module (202b) located adjacent to the first power module are operating at different states of charge. After determining that the second power module is at the lower state of charge than the first power module, a negative-side switch (218a) associated with the second power module is adjusted to an open position, thereby preventing flow of electrical current from a negative terminal (222b) of the second power module to electrical ground.