Centre for Automotive Energy Materials (CAEM)
Globally, there is an urgent need for the development of alternative energy sources, especially for the automotive sector, due to the alarming depletion of the fossil energy reserves. Lithium-ion battery has emerged as a promising candidate to alleviate this problem due to its attractive features viz high energy density (both volumetric and gravimetric), high current drain, high cycle life, low self-discharge, absence of memory effect, good low temperature performance. For the Lithium-ion batteries, India's market share is significantly high in the area of consumer electronics. It is expected to increase in the Electric Vehicle sector also. However, in India, till date, there are no manufacturers of Lithium-ion cells; It is hence comprehensible that there are no manufacturers of most of the raw materials for the batteries also. Keeping in view the rapid growth of the Automotive Industries and the need for the development of the material technology for sustainable transportation, ARCI has taken up a major project to develop Li-ion battery materials for EV/HEV by setting up the manufacturing of Lithium-ion cells and battery packs at pilot plant scale for automotive application. The project is planned to be executed in a twofold approach. One aim is to set up the state-of-the-art pilot scale facility and establish the manufacturing technology with internationally proven commercial electrode materials for the fabrication of Li-ion battery. The other aim is to indigenously develop the technology for producing the standard electrode materials/new materials, and test them for the charge/discharge characteristics. The optimized process or the Material Technology will be scaled up and tested in the Lithium-ion battery pilot plant facility aimed to be set up.
The novelty in the whole approach of the project lies in establishing the Li-ion battery line for EVs and deriving the nano technology on processing the conventional as well as newer electrode materials indigenously. In the whole process of the project, a close interaction and trials will be aimed at with leading Indian automotive manufacturer Mahindra Reva to validate the Lithium-ion battery manufacturing technology developed indigenously.
The following are the expected outcomes of the project:
- Setting up a pilot scale facility for the fabrication of the Lithium-ion cell, and development of the technology for E-bus battery of capacity 330V, 200 Ah and batteries for E-cars
- The Pilot plant facility will also cater to other capacity batteries required for E-scooter and E-car. This will meet the needs of the automobile industry in the country for reducing Green House Gas Emission and foreign exchange for importing the oil which is the Ultimate Goal of the project.
- Electrode materials and other components for Li-ion battery (LIB) will be developed indigenously. This offers scope for the in-house development of tailor-made LIB for a wide variety of Niche applications.
Under this project two major magnetic programmes for automotive applications are executed at CAEM, Chennai. The two magnet programmes are (i) Development of Nano Soft magnetic Materials based on Fe-P system and (ii) Development of Nanostructured High performance Permanent magnets based on SmFeN system and grain boundary engineered NdFeB magnets. The necessity and the goals of these programmes are highlighted below:
Development of Nano Soft magnetic Materials based on Fe-P system:
By virtue of large volume utilization of soft magnetic materials in many electro-technical devices in automobiles, where the quantum of requirement is increasing day-by-day, there is a pressing need for the development of alternate soft magnetic materials not only to minimize the cost but also to enhance the device performance and hence energy saving. This impact is well understood world over, and new soft magnetic alloys are required with superior magnetic properties as a possible alternative to the conventional Si-steel. Such an indigenous development of a new soft magnetic material will be a boon to the automobile industries in India. Transformers, motors, choke coils, inductors are examples of applications where soft magnetic materials are invariably used. In recent times, there is a growing demand to develop new high Bs - low core loss materials for energy efficient automotive applications. In this context, Fe-based amorphous / nanocrystalline alloys have been extensively investigated as they show a low core loss (< about 20% of Si steel) but with reduced Bs, which is about 80%, lower than that of Si- steels. Si steel which is used extensively in auto sectors have reached the saturation in its magnetic performance and hence new alloy developments have to be directed towards achieving much better soft magnetic characteristics for applications. With this in mind, ARCI has taken up the programme to develop new soft magnetic alloy based on Fe-P system for EV motor applications.
Development of Nanostructured High performance Permanent magnets based on SmFeN system and grain boundary engineered NdFeB magnets:
Sintered Nd-Fe-B magnets with high coercivity (>15 KOe) are required for Hybrid Electric / Electric Vehicle applications so that the magnets can deliver its performance when the motor temperature rises to 2000C. To achieve high coercivity Dy addition is essential in Nd-Fe-B magnets. However the addition of Dy offsets the cost of the magnets as its natural resources are limited. With scarce availability of Dy, R&D efforts are being directed to develop NdFeB magnets to minimize the consumption of Dy. In this context, it is worth to mention about the research work towards realization of property enhancement by grain boundary diffusion of Dy in NdFeB magnets. Dy by virtue of its high uniaxial anisotropy, increases the coercivity of the magnet when present at the grain boundaries. Thus, high residual induction on account of the Nd-Fe-B matrix phase and high coercivity on account of Dy at the grain boundaries can be achieved. Keeping in view of these developments, an R&D activity is proposed towards coercivity improvement in commercial NdFeB magnets by diffusion of Dy along the grain boundaries.
Parallely , ARCI is also carrying out R&D under this project to develop samarium-iron-nitride (SmFeN) magnets as an alternate candidate to Nd-Fe-B. Sm-Fe-N magnets have a higher intrinsic coercivity when compared to the NdFeB magnets,, which means that they do not need the scarce dysprosium as an additive to give rise to high coercivity. The advantages of the SmFeN magnets are similar to those of SmCo magnets, containing the alloys SmCo5 or Sm(Co,Fe,Cu,Zr)17. The major advantage of SmFeN magnets over SmCo magnets is that they do not contain cobalt, which is not as widely available and cheap as iron. The main reason why the SmFeN magnets are not on the market yet is because their preparation is very challenging and not all manufacturing problems have been solved yet and ARCI would like to concentrate on these issues in developing high coercivity Sm-Fe-N magnets. In development of high coercivity Nd-Fe-B and Sm-Fe-N magnets, CAEM will closely interact with Automotive sectors to make prototype EV motors.
In a conventional automobile, an effective way of utilizing the excess waste heat of fuel combustion for vehicular operation will result in many benefits both from economic and environmental point of view. A thermoelectric generator (TEG), which converts the heat into electricity, is one of the ideal methods for this purpose. However, the efficiency of TEG available as on today are very low (around 5-8%), to use them for this application it has to be enhanced significantly at least to more than 10%. Nanostructuring the material used in conventional TEG is one approach, which increases figure of merit (zT), there by the efficiency is also improved. Recently, by this approach zT of more than 2 and efficiency as high as 15 % was achieved in a lead telluride based alloy. The objective of the present project is to (i) develop CoSb3, Zn4Sb3, Pb-Te-Sb and NaxCoO2 based TE modules with zT more than 2 by nanostructuring approach (b) build a prototype TEG device from these materials and (c) evaluation of their performance in a simulated vehicle condition of 1.0-1.5 liter engine. The choice of the materials for this application is based on operating temperature requirement as the exhaust gases in most of the automobiles are between 200-400oC. Under this Project, facilities for materials processing and characterisation of figure of merit of TE materials are being setup in the thermoelectric research lab at Centre for Automotive Energy Materials (CAEM), Chennai