Pressure Pad Sensor Calibration for Pouch Cell Surface Pressure
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Solution Overview
Problem
Current methods for measuring the surface pressure of lithium-polymer pouch-type secondary batteries are inadequate, particularly due to the use of expensive and bulky jigs, and existing pressure pad sensors suffer from manufacturing errors leading to inconsistent output values across sensing nodes.
Innovation Solution
A pressure pad sensor pressing device that applies uniform pressure to each sensing node using a pressing unit with a node pressing portion and weight loading portion, supported by a frame and driven by multiple units, allowing for precise measurement and calibration of output values using a method that interpolates standard pressure data from multiple applied pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a jig including a load cell is used to measure surface pressure of pouch-type secondary batteries, then measurement capability is achieved, but the device becomes expensive and bulky
Solution Approach 1:
The pressure measurement function is divided into multiple independent sensing nodes distributed across the pressure pad sensor surface. Each sensing node independently measures pressure at its location, enabling comprehensive surface pressure measurement without requiring a single complex load cell device. This segmentation allows the use of simpler, smaller sensing elements while achieving the overall measurement capability.
Solution Approach 2:
The traditional mechanical load cell is replaced with electronic pressure sensing nodes that convert mechanical pressure directly into electrical signals (resistance changes). This substitution eliminates the need for bulky mechanical components and enables integration into a thin, flexible pressure pad sensor structure while maintaining measurement functionality.
2Productivity
If pressure pad sensor sensing nodes are manufactured with standard processes, then manufacturing efficiency is maintained, but output values vary due to manufacturing errors
Solution Approach 1:
A calibration process is performed before the pressure pad sensor is deployed for actual measurements. During calibration, known reference pressures are applied to each sensing node, and the corresponding output values are recorded and stored. This preliminary action creates a calibration dataset that compensates for manufacturing variations, allowing each sensing node to be accurately mapped to real pressure values despite production tolerances.
Solution Approach 2:
The relationship between sensing node output and actual pressure is adjusted through calibration parameters. By measuring the output of each sensing node under known pressure conditions and establishing correction factors or lookup tables, the system transforms inconsistent raw outputs into accurate pressure measurements. This parameter adjustment resolves the inconsistency caused by manufacturing variations.
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 enables accurate and uniform measurement of swelling pressure distribution across battery cells by converting inconsistent output values into reliable standard pressure data, overcoming manufacturing errors and improving measurement precision.
Implementation Method 1
Each sensing node may be composed of a force sensitive resistor (FSR) sensor using a property that a resistance value is changed according to physical force, weight, and the like
Data Source
AI summary
A pressure pad sensor pressing device includes a pressing unit including a node pressing portion provided to descend from a predetermined height and contact one of the sensing nodes, and a weight loading portion provided at the top of the node pressing portion so that a weight load is transmitted to the node pressing portion; a support frame supporting the pressing unit at a predetermined height; and a first driving unit for moving the pressing unit in the first direction or in the reverse direction, a second driving unit for moving the pressing unit in the second direction or in the reverse direction, and a third driving unit for lifting and lowering the pressing unit with respect to the pressure pad sensor, and a calibration method capable of calibrating the output value of the sensing node to a reliable pressure value using the pressure pad sensor pressing device.