Optical Fiber Sensor for In Situ HF Detection in Li-Ion Batteries

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Solution Overview

Problem

Existing electrochemical energy devices, such as lithium-ion batteries, face challenges in detecting and managing moisture and fluid products like hydrofluoric acid (HF), which can lead to cell degradation and capacity loss due to their aggressive chemical properties and potential for passivating the anode and cathode materials.

Innovation Solution

An optical detector system comprising a first optical fiber element and a second optical fiber element with a material that converts upon chemical reaction, allowing for real-time detection of chemical compounds like HF, HCl, or HBr within the electrochemical device, using a polarization-maintaining optical fiber and an evaluation device to determine the presence and concentration of these substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional electrochemical cells are used without specialized detection systems, then device simplicity is maintained, but the ability to detect and measure harmful fluid products like HF, HCl, or HBr is lost

Engineering Contradiction:
Improvedetection of fluid productsVSAvoiddetection system structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The optical fiber sensor is integrated directly into the electrochemical cell structure, with the sensing element nested within the cell housing. This allows the detection system to be embedded within the existing device architecture, achieving precise measurement of fluid products without significantly increasing overall device complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

An optical fiber serves as an intermediary element that transmits light signals between the external measurement system and the internal chemical environment. The optical fiber enables detection of harmful substances through optical interactions (absorption, fluorescence, or refractive index changes) without requiring direct electrical or physical contact with the reactive fluid products

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If real-time detection of chemical compounds is implemented, then cell degradation can be prevented, but the complexity of the monitoring system increases

Engineering Contradiction:
Improveprevention of cell degradationVSAvoidmonitoring system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The optical detection system provides continuous real-time feedback on the concentration of harmful fluid products within the electrochemical cell. This feedback mechanism enables early warning and preventive action before degradation occurs, with the optical signal continuously monitoring the chemical environment and transmitting data to external analysis systems

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The optical fiber sensor is pre-installed within the cell structure during manufacturing, positioning the detection element in advance to monitor for potential harmful substances before they accumulate to dangerous levels. This preliminary detection capability allows for preventive maintenance and extends cell lifespan

Inventive Principle:
Principle #10Preliminary action

3Difficulty of detecting and measuring

If optical fiber sensors are integrated into the electrochemical cell, then in situ detection capability is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improvein situ detection capabilityVSAvoidintegration process
Core Design Contradiction:
Difficulty of detecting and measuringVSEase of manufacture

Solution Approach 1:

The detection system is divided into separate modular components: the optical fiber sensor element, the cell housing with integrated mounting features, and the external measurement instrumentation. This segmentation allows each component to be manufactured and tested independently, then assembled together, reducing overall manufacturing complexity while maintaining in situ detection capability

Inventive Principle:
Principle #1Segmentation

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

Enables real-time, in situ detection of chemical compounds, effectively monitoring moisture and fluid products in electrochemical devices, preventing cell degradation and optimizing performance by accurately determining the presence and concentration of harmful substances.

Implementation Method 1

a first material (138) which is adapted to be converted into a second material (140) upon a chemical reaction with at least one chemical compound (142) to be detected

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

an optical fiber element having a first end and a second end, the optical fiber element having a core of an optical transparent material and a cladding surrounding the core

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3517938B1Optical detector and method for detection of a chemical compound
Publication Date: 2020.09.16 KARLSRUHER INST FUR TECH
  • EP3517938B1 patent drawingFigure 1~2c
  • EP3517938B1 patent drawingFigure 3a~3d
  • EP3517938B1 patent drawingFigure 4a~4b

AI summary

The present invention relates to an optical detector (110) and a method for a detection of a chemical compound, wherein the optical detector (110) comprises - a first optical fiber element (112), wherein the first optical fiber element (112) is designed to guide at least one optical signal (122) and at least one modified optical signal (146); - a second optical fiber element (126), wherein the second optical fiber element (126) is adapted to communicate with the first optical fiber element (112), wherein the second optical fiber element (126) is designed to receive the at least one optical signal (122) provided by the first optical fiber element (112) and to emit the at least one modified optical signal (146) to the first optical fiber element (112), wherein a partition of the second optical fiber element (126) comprises a first material (138) which is adapted to be at least partially converted into a second material (140) upon a chemical reaction with at least one chemical compound (142) to be detected, wherein the at least one modified optical signal (146) depends on a conversion of the first material (138) into the second material (140) by the chemical compound (142); and - an evaluation device (148), wherein the evaluation device (148) is adapted to determine at least one property related to the chemical compound (142) by evaluating the at least one modified optical signal (146) provided to the evaluation device (148) by the first optical fiber element (112). The optical detector (110) allows a real-time detection of at least one chemical compound (142), in particular, a fluid product generated in an electrochemical energy device, including but not limited to at least one of HF, HCl, or HBr, in an in situ and/or an in operando manner.