Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - SPICY (Silicon and polyanionic chemistries and architectures of Li-ion cell for high energy battery)

Teaser

SPICY is a collaborative research project to develop a new generation of Li-ion batteries meeting the expectations of electrical vehicle end-users, including performances, safety, cost, recyclability and lifetime. Batteries can fulfil the need for a constant, efficient, clean...

Summary

SPICY is a collaborative research project to develop a new generation of Li-ion batteries meeting the expectations of electrical vehicle end-users, including performances, safety, cost, recyclability and lifetime.

Batteries can fulfil the need for a constant, efficient, clean, safe and renewable power supply for vehicles. Battery storage systems have been recognized by all stakeholders as a key enabling technology to optimize energy recovery and energy management of the whole vehicle with an appropriate level of safety while respecting the environment. Worldwide, the most significant technological challenges currently facing electric vehicles are the cost and performance of their components, particularly the battery. The development of new chemistries and cell architectures for Li-ion battery is the only way to increase cell capacity and possible energy density which could lead to greater electric vehicle autonomy.
Large automotive batteries will be implemented “locally – worldwide” due to cost associated to ship them. This means that our technology has great chance to stay in European manufacturing facilities over long term, ensuring sustainable employment and economic opportunities.

In this context, SPICY is considering the development of new chemistry materials, cell architectures and packaging with the support of understanding and modelling activities.

Work performed

Based on the polyanionic chemistry, a Plug-in Hybrid Electrical Vehicles (PHEV) application has been defined. This application has served as background to define specifications at cell level and in general specifications for WP2, 3, 4, 5 and 6.

Various LFMP materials have been synthesized by solution route but did not reach the objectives. Thus, solid state route has been used and reach 95% of the objective. High voltage electrolytes based on sulfolane (SL) and adiponitrile (AND) have been tested and full graphite/NMC Li-ion cell has been operated at 4.5V with good performance.

A new graphite material has been selected which is going over the specifications. Regarding the electrolyte, original approach has shown that imide sacrificial salt could significantly reduce the first irreversible capacity.
Concerning silicon material synthesis, the 2 reactors of synthesis have been updated based on flow modelling. It opens the way now of efficient material.

Some Components have been updated based on benchmarking and water based formulation has been developed for positive and negative electrodes for Gen-1 with 1000 cycles demonstrated. An original battery stack architecture has been designed. A modular lightweight and robust plastic composite packaging is associated to a power connector allowing rotation between 2 packaging.

113 Gen-0 cells have been delivered to partners for evaluation with the objective to compare the 4 different cell architectures. This comparison is particularly unique as all electrodes, electrolyte, separator and formation protocol are the same. Gen-1 electrode upscaling has started and cells are expected beginning of 2017.

Management of the tests done by 5 partners was a huge work to validate protocols of each partner as data recovery in the way to have an exploitation. Abusive tests have shown really different results regarding packaging. Exploitation of electrical test is in progress. For post-mortem analysis, only ante-mortem has already been performed on fresh cells. They have allowed to define the relevant tests and to validate the protocols. For algorithm definition, equivalent models have been proposed which allow to estimate the SOC and the SOH.

Gen-0 and Gen-1 electrode models were developed. Compared to the reference Newman model, a collocation model was proposed with calculation time reduced. This electrode models were then expanded with a 2D current collector and 3D thermal model in a free software. Experimental data will be necessary to validate them but they will allow to propose cell optimizations.

During packaging design, there were discussions to take into account recycling step. Water based electrodes are definitely more sustainable, as organic solvent is suppressed and as fluoride gas during recycling process. A recycling process allowing to recover more than 50% of the battery has been identified.

Final results

The works of SPICY project, from components development to cell evaluation, modeling or recycling, are done based in the framework of the end-users specifications. Partners evolving in SPICY project are so completely in link with industrial concerns. The around fifteen PhD students and post-docs evolving in SPICY project will be also particularly well formed personnel to go with the launching of new production in Europe. The works done are also generating innovation in terms of knowledge, components or understanding which will also be part of the stronger position from European industry.

Integrated solution of hybrid storage system allows fitting with the different scenari of electric vehicle use. The so-called “Molded Interconnected Devices” combined with plastic packaging for cells should lead to highly integrated compact systems with higher level of safety, volume reduction, optimized electrical interconnections and cost reduction. The design of a modular lightweight and robust plastic composite packaging associated to a power connector allowing rotation between 2 packaging is already done and concept proofs will be evaluated in the next months. This modular approach allows to define various battery pack configurations, in terms of volume or compromise between energy and power.

We have revised cell density energy at 110, 140, 165 and 190 Wh/kg for the 4 different generations cells’ design (reference generation, Gen-1, Gen-2 and Gen-3) allowing to deliver more power. The reference generation assembled by PROLLiON were at the level expected for the reference polyanionic graphite chemistry. The Gen-1 planned at the middle of the project is not already assembled but cells design based on components selection is still in line with the target, as 139 Wh/kg has been expected by CIDETEC, particularly due to a lightest packaging but also to a new graphite and thinner current collector. Regarding cost, this Gen-1 will be assembled with water based electrodes both at cathode and at anode, which is environmentally more sustainable with cost reduction associated of around 10-15%. LCA will define precisely the benefit. For Gen-2 and Gen-3, new polyanionic chemistry and silicon chemistry which are under development will certainly demonstrate, in relevant Li-ion cells for electrical vehicle, improvement of cell-level energy densities of at least 20%, and 20% costs reduction.

Simulations models and tools address shortcomings of today’s Li-ion battery technologies. Strong activities are dedicated to simulation on SPICY. Model were developed for the chemistry of the Gen0, Gen1 and Gen2. Compared to the reference Newman model, a collocation model was proposed which decreases significantly the amount of freedom degrees from 1000 to 50. Calculation time will be so clearly reduced. This electrode models were then expanded with a 2D current collector and 3D thermal model in a free software Elmer and COMSOL. They need to be validated with experimental data in the next months. These models, with fast answer and adapted to the new chemistry will support development of optimized Li-ion cells resulting in cells with higher performance and shorter time to market.

Website & more info

More info: http://www.spicy-project.eu.