Interdigital Capacitive Pressure Sensor for Compact Battery Modules
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Solution Overview
Problem
Conventional pressure sensors are unsuitable for compact and reliable pressure monitoring in densely packed battery modules due to their bulky design, insufficient sensitivity, and susceptibility to drift, posing a risk of defects and fires in battery cells.
Innovation Solution
A capacitive pressure sensor with interdigital electrodes and a pressure-sensitive material containing particles with different permittivity, arranged on a flexible substrate, allowing for compact and sensitive pressure detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pressure sensors are used, then pressure monitoring is possible, but the sensor design becomes bulky and sensitivity is limited
Solution Approach 1:
The patent replaces conventional mechanical pressure sensing elements with a capacitive sensing mechanism. The pressure-sensitive material contains particles with different permittivity that change their spatial distribution under pressure, causing capacitance changes between interdigital electrodes. This substitution of mechanical sensing with electrical field-based sensing enables compact sensor design while maintaining pressure monitoring capability
Solution Approach 2:
The pressure-sensitive material is designed as a composite consisting of a dielectric matrix embedded with particles of different permittivity. This composite structure allows the material to exhibit pressure-dependent dielectric properties, where applied pressure changes the particle distribution and thus the overall permittivity, enabling sensitive pressure detection in a compact form factor
2Measurement precision
If SMD-based pressure sensors are used to achieve sufficient sensitivity, then sensitivity is improved, but the sensor design becomes bulky
Solution Approach 1:
The patent employs thin-film technology by depositing interdigital electrodes and the pressure-sensitive material as thin layers on a flexible substrate. This thin-film approach enables high sensitivity pressure detection while maintaining an extremely compact form factor, directly addressing the contradiction between sensitivity and size that plagues SMD-based sensors
3Volume of moving object
If resistive pressure sensors are designed in strip form for compactness, then sensor size is reduced, but reliability decreases due to drift susceptibility
Solution Approach 1:
The patent replaces the resistive sensing mechanism with a capacitive sensing mechanism. Instead of measuring resistance changes that are prone to drift, the sensor measures capacitance changes resulting from pressure-induced variations in the dielectric properties of the pressure-sensitive material. This substitution fundamentally improves measurement stability and reliability while maintaining compact dimensions
4Volume of moving object
If capacitive pressure sensor components are arranged within the same layer, then sensor compactness is improved, but manufacturing complexity may increase
Solution Approach 1:
The patent merges the electrodes and pressure-sensitive material into a single planar layer structure. The interdigital electrodes and pressure-sensitive material are co-planar, eliminating the need for multiple stacked layers and enabling extreme miniaturization. This merging approach simplifies the overall device architecture while achieving compact form factor
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
The sensor achieves high sensitivity and reliability with a compact design, enabling easy installation and monitoring of battery cell pressure, reducing the risk of defects and fires.
Implementation Method 1
When the sensor layer is subjected to pressure, this leads to elastic deformation of the pressure-sensitive material
Implementation Method 2
Clusters relative to each other cause a change in the permittivity of the pressure-sensitive material, which can be measured as a change in capacitance
Implementation Method 3
the particles have a significantly higher or a significantly lower permittivity than the dielectric material
Data Source
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AI summary
The invention relates to a capacitive pressure sensor (2) with a sensor layer (6) arranged on a substrate layer (4) and having an interdigital electrode (8) that has two electrodes (8a, 8b) printed onto the substrate layer (4) and interlocking in a comb-like manner, wherein a pressure-sensitive material (10) is arranged between the electrodes (8a, 8) and is formed from a compressible dielectric material containing particles with a permittivity different from that of the dielectric material, arranged in isolation from one another. The invention further relates to a method for manufacturing such a sensor (2).