Self-Supervised Encoder for Fault Prediction in Electrochemical Cells

TL;DR

This paper introduces a self-supervised neural network encoder-decoder model for fault prediction in electrochemical cells, significantly improving early fault detection and interpretability over traditional parametric models.

Contribution

It proposes a novel self-supervised encoder-decoder neural network architecture that better predicts cell voltage and detects faults earlier than existing parametric models.

Findings

Reduced voltage prediction error by 53%

Predicted faults 31 hours in advance, 64% earlier than previous models

Enhanced interpretability through encoder output visualization

Abstract

Predicting faults before they occur helps to avoid potential safety hazards. Furthermore, planning the required maintenance actions in advance reduces operation costs. In this article, the focus is on electrochemical cells. In order to predict a cell's fault, the typical approach is to estimate the expected voltage that a healthy cell would present and compare it with the cell's measured voltage in real-time. This approach is possible because, when a fault is about to happen, the cell's measured voltage differs from the one expected for the same operating conditions. However, estimating the expected voltage is challenging, as the voltage of a healthy cell is also affected by its degradation -- an unknown parameter. Expert-defined parametric models are currently used for this estimation task. Instead, we propose the use of a neural network model based on an encoder-decoder architecture. The network receives the operating conditions as input. The encoder's task is to find a faithful representation of the cell's degradation and to pass it to the decoder, which in turn predicts the expected cell's voltage. As no labeled degradation data is given to the network, we consider our approach to be a self-supervised encoder. Results show that we were able to predict the voltage of multiple cells while diminishing the prediction error that was obtained by the parametric models by 53%. This improvement enabled our network to predict a fault 31 hours before it happened, a 64% increase in reaction time compared to the parametric model. Moreover, the output of the encoder can be plotted, adding interpretability to the neural network model.