Battery Cell Compression Bench for Precise Thickness Measurement
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Solution Overview
Problem
Existing mechanical characterization benches for battery cells, particularly negative electrodes, face challenges in precision due to inhomogeneous pressure application and deformation of the frame, which affects the measurement of thickness variation during charging and discharging, leading to issues like accelerated aging and premature failure.
Innovation Solution
A bench with a frame, movable element, and force sensors that isolate the compression face from frame deformation, ensuring homogeneous pressure application through a recess and punctual contact connections, allowing precise measurement of thin object thickness variations under controlled force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a press applies a vertical force on the entire cell through a frame, then the cell can be compressed, but the frame deforms and applies inhomogeneous pressure, reducing measurement precision
Solution Approach 1:
The compression system is segmented into independent compression faces supported by the frame, rather than using a single rigid press. This allows each compression face to be independently supported, preventing frame deformation from affecting pressure distribution.
Solution Approach 2:
The frame acts as an intermediary structure that supports the compression faces directly, isolating them from the deformation of the overall press structure. This intermediary support system ensures homogeneous pressure application while maintaining measurement precision.
2Device complexity
If the frame is used to support compression faces, then the structure is simplified, but the frame deformation transmits parasite deformation to the compression face, skewing measurements
Solution Approach 1:
The frame is designed with local reinforcement at the compression face support zones, creating areas of high stiffness where needed while maintaining overall structural simplicity. This localized quality improvement prevents parasite deformation without requiring complete frame redesign.
3Stress or pressure
If pressure is applied to the entire cell, then the cell structure is compressed, but the pressure is inhomogeneous, affecting measurement accuracy
Solution Approach 1:
The compression faces are designed to distribute pressure homogeneously across the cell surface through direct frame support. This ensures uniform stress distribution during compression, enabling accurate thickness variation measurements without the distorting effects of inhomogeneous pressure.
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 solution provides reliable and precise mechanical characterization of thin objects, such as battery cells, by ensuring uniform pressure and accurate measurement of thickness changes, optimizing material and design for improved performance and longevity.
Implementation Method 1
at least one force sensor... to measure the variation in thickness of the thin object
Implementation Method 2
at least one movement sensor to measure the variation in thickness of the thin object
Data Source
AI summary
A bench for mechanical characterisation of a battery cell by applying a compression force includes a frame having a first compression plate, a movable element having a second compression plate opposite the first compression plate, a compression spring for applying a compression force to the cell between the first and second compression plates, a force sensor inserted between the movable element and the spring, and movement sensors measuring the movement between the first and second compression plates. The first compression plate includes a projecting compression zone with an area equal to a portion of interest of the cell and the frame includes a recess surrounding a thicker frame in the frame forming a pedestal supporting the first compression plate.