MEASUREMENT & MONITORING THICKNESS MEASUREMENT
MICRO-EPSILON
Factors to consider when measuring thickness in battery production
Energy storage devices such as lithium-ion batteries play a crucial role in electromobility and energy transition . In order to optimise battery production , sensors are required to monitor the production line , including thickness measurement sensors . But what are the challenges in making reliable thickness measurements , asks Glenn Wedgbrow , Business Development Manager at Micro- Epsilon UK .
The growing demand for energy storage devices such as lithium-ion batteries and fuel cells are being met by Giga factories that are equipped with efficient , highly automated production technologies . In order to optimise battery production , sensors are required that monitor the production line to the highest accuracy and dynamics . These sensors include high precision distance sensors , infrared temperature measurement technology ,
as well as 2D / 3D profile sensors for the many measurement tasks involved in battery production such as electrode manufacturing , assembly and forming processes .
In battery production , one of the key quality control parameters is the thickness ( and width ) of film and strip materials , wet layers and electrode coatings . These require sensors that measure thickness reliably as the material is being processed ( inline ), helping to optimising production yields while minimising waste . All manufacturers will have a process specification that they will need to meet in order to satisfy their customers . But in reality , how can a manufacturer be sure that they are meeting these specifications at all times and what are the challenges they face ?
A number of different measurement systems can be used to measure the thickness of a material . Some of these are used offline , i . e . random samples of the material are removed from production and measured to verify that they meet the specification . A more effective approach is to install an in-process or fixed , inline non-contact measurement system that continuously measures the thickness of the material as it is processed . If measurements from these systems move towards the outer limits of the specification , machine and process control parameters can be altered to bring the thickness back into acceptable limits .
REAL WORLD ERRORS
A key factor to consider when selecting a suitable system from a supplier is to understand the combined real-world errors that can occur when using a non-contact thickness measurement system and how these errors can be eliminated or compensated for . While many suppliers state on their datasheet that the measurement system meets a certain resolution and linearity , in the real world , this performance is affected by a number of environmental influences . Errors associated with real world thickness measurement are not always so obvious , but can combine to create significantly large errors . It is therefore critical to select a system based on system accuracy , not just sensor accuracy .
98 PECM Issue 53