e-TRNL Energy is working on a new prismatic cell manufacturing technology

Mumbai headquartered battery tech start-up e-TRNL Energy recently announced raising a pre-seed round of INR 7.5 crores. The start-up is working on a proprietary cell manufacturing technology that claims to deliver safer, faster charging batteries with better energy density. In this Q&A, co-founder Apoorv Shaligram shares more about their work. 

Please help us understand which aspects of battery technology you are working on. 

We have been working on a chemistry-agnostic battery cell manufacturing technology for the last year and a half. 

Today, we have cylindrical cells, prismatic cells or pouch cells in lithium-ion batteries. These are the three available formats. We are working on a new prismatic cell format. Essentially we redesign the battery from scratch so that the flow of current is reoriented inside the cell, which allows us to make a lot of improvements on the core performance metrics. 

Tell us more about your solution and approach.

There are certain fundamental constraints about a battery that cannot be changed for any particular cell. For example, batteries heat up, and one cannot really do much about the heating because of the design of the cell. The batteries heat up, and then you decide to cool it. The energy required to cool also has to come from the battery itself!

So, we started with one fundamental question – How can we prevent heating in the first place? There was only one answer – If we want to prevent heating, we must change the design. 

The most widely used cell in the Indian market today is the cylindrical cell in 18650 format or 21700 format. If you look at the construction of these cells, the current does not flow in a straight line from the negative to the positive terminal. It flows in a spiral and probably takes a path 10X longer than what it is supposed to flow through. In our design, the path of the current is reoriented in such a way that it passes through the minimum distance. The current is spread out over a large area, and it passes through the shortest dimension of the cell in a straight line. Now, you have a wide highway to go from your starting point to the destination, and on top of that, it is a very short distance so your energy consumption (wastage) is going to be much lower. 

We came up with this new design, but the difficult part is to make it manufacturable. A completely new cell design has typically been difficult to manufacture, and that is one of the primary reasons people have not changed the existing manufacturing type. We have come up with this manufacturing technology (still in R&D). We have done enough proof of concept to know that what we are thinking of is workable and delivers a better cell.

Can you share how your cell manufacturing process differs from the existing processes?

The cell manufacturing process we are working on actually cuts down the process flow by almost half compared to the conventional cell manufacturing process. We also anticipate that it would result in around an 80% reduction in CapEx. 

We are going with a concept called 3DEATM (3D Electrode Architecture), wherein we do not have conventional coated electrodes. Coating and drying of electrodes is not required. It is a completely different process, but I cannot reveal much at this stage. 

In terms of technology readiness, where do you stand at the moment?

We’re at an early stage R&D right now. We have done internal trials and proof of concept on the manufacturing technology, but as a product, it is quite an early stage right now. We aim to reach TRL 5 or TRL 6 in a year from now and be market-ready.

Also Read: India’s aspirations for cell manufacturing and the necessity to develop a supply chain

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