Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras

Postmortem Analysis of Batteries

Funding Agency Details

Mahindra Electric Mobility Limited

Department

Chemical Engineering​

Description

Dismantling the batteries:
The battery cycling at appropriate conditions will be carried out at MahindraElectric Mobility Ltd. and they will shipped out to IIT-Madras for postmortem analysis. It is essential to carry out the postmortem analysis in the inert atmosphere so as to avoid the decomposition of the materials. In the proposed project, either a nitrogen filled glove bagor box will be used to dismantle the batteries. The mechanical dismantling of batteries using appropriate cutting tools will be employed. We propose to discharge the battery completely before cutting them open, to avoid potential flame/fire hazard due to short-circuit. After the cells are cut open, theirvisualsimages will be captured using standard DSLR camera. Samples of appropriate size for cross-sectional SEM/EDAX imagingwill be prepared.The prepared samples will be transferred to SEM/EDAX machine using inert atmosphere box/dessicator to prevent the decomposition while transit.
Microscopic (SEM) imaging and elemental mapping:
The samples from the dessicator/inert-atmosphere box will be transferred immediately to the SEM sample stage and care will be taken to ensure minimal ambient exposure during sample transfer. All the necessary adjustments will be made to find the appropriate location within the sample to identify appropriate crosssection to clearly view negative-electrode/SEI and positive-electrode/SEI layer. Once a clear image with best possible magnification/resolution is achieved, elemental mapping will be carried out using Energy Dispersive X-ray Spectropscopy. It is recommended to provide IIT-M team with the possible elements to visualize in the mapping. This would facilitate us focus on select set of elements that Mahindra Electric Mobility Ltd. in interested in. IIT-Madras imaging team will put in best efforts to provide two microscopic images (negative-electrode/SEI and positive-electrode/SEI) per cell and their respective elemental mapping with EDAX.

Problem Statement

The lithium ion batteries used in the electric vehicles are predominantly tested under standard testing conditions. However, the load profile being encountered by the batteries under real conditions are significantly different. In the proposed project, Mahindra ElectricMobility Ltd. will carry out appropriate battery charge-discharge measurements as per the requirements of their R

Outcome of the Research

A progress report will be provided at the end of every month which will contain all the information on (i) cellopening and any unusual observations during the postmortem procedures(ii) Visuals/images of the original and dismantled cells(iii) SEM images depicting the cross section of cell electrodes/SEI layer(iv) EDAX elemental mapping corresponding to the SEM images(v) Our inferences and summary

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