Cygni Energy Inaugurates BESS Manufacturing Facility

We at Cleantech Hero had the opportunity to interact with Venkat Rajaraman, Founder & CEO – Cygni Energy, to talk about their recently inaugurated battery pack manufacturing facility.

Located in Maheshwaram, Hyderabad, the facility has been set up with an initial capacity to produce 4.8 GWh of battery packs for electric vehicles (EVs) and energy storage systems. The production line is capable of manufacturing 105 kWh liquid-cooled base modules using 3xx (like 314Ah) cells. This interview explores the operational and economic aspects of their INR 100 crore investment, as well as the company’s vision for energy storage solutions.

Can you please provide an overview of Cygni’s BESS gigafactory, including its product portfolio and current production capacity?

Our BESS Gigafactory is an automated facility rated for 4.8 GWh of BESS manufacturing and scalable to above 10 GWh in the future. We can undertake cell to pack to container assembly in this facility and offer end-of-line testing at full rated capacity of the BESS container (called Factory Acceptance Testing or FAT in industry parlance).

Each building block of the assembly line has been selected from top-of-the-line suppliers and integrated by us. This Lego block approach enables the assembly line to be modular and highly adaptable to future requirements. The line can already handle the next generation of cells 5xx and 10xx cells (like 587Ah to 1085Ah cells), hence subsequent changes at the cell level can also be accommodated with minimal changes. Lastly, the entire facility runs with an MES (Manufacturing Execution System) which tracks parameters at each step, provides insights into manufacturing productivity and helps us continuously improve.

We have planned additional investments of around INR 250 Cr to reach our full rated capacity and set up an automated container integration unit, which will further boost productivity and quality.

Can you discuss the current order book and scale of business?

Between mobility and BESS, we have an order book of over 1 GWh already, and we have pre-bid arrangements in place with multiple developers to support them to win the ongoing BESS tenders.

This pipeline is expected to translate into a revenue of over 800 Cr in the next 18 months.

Battery storage is often seen as expensive or complex. How does Cygni’s BESS technology help make energy storage more practical and affordable?

Battery storage systems are complex because they need significant in-built control and safety systems. However, the EMS (Energy Management System) provides easy-to-control web-based access to the BESS installation. The EMS provides user-relevant insights such as utilisation, system health, round-trip efficiency, cost savings, etc., and allows them freedom to operate the asset in a way that’s safe and easy to understand.

The systems are becoming increasingly affordable now due to the modularity of the design, i.e. building large systems with smaller, easy-to-manufacture blocks. For instance, a 100 MWh BESS plant would have 20 containers, and each container has 48 standard packs. These 960 standard packs form the backbone and lend scale to the manufacturing.

What are the key features of your BESS solutions that make them reliable and unique?

All large-scale BESS systems are complex and fundamentally built around managing an electrochemical element (the cell) within tight tolerances of performance to achieve the required performance.

The reliability of our systems thus stems from a deep and nuanced understanding of these cells, validation of our design using cutting-edge simulation tools, and ensuring fidelity between the design and the actual product through our automated BESS manufacturing line. For instance, we have a detailed cell qualification process that takes nearly 6 months and rigorously tests the cells to build unique insights into their performance and translate that into tangible data for cell quality checks, sorting thresholds, BMS configuration parameters and thermal management strategies.

Similarly, one of the ways in which we ensure fidelity between the design and the actual product is by feeding the above-mentioned parameters into our MES (Manufacturing Execution System) which ensures that each station of the manufacturing line (e.g. laser welding, cell sorting etc) operates with these parameters eliminating the scope for operator error.

You claim that your battery systems can fully replace diesel generators. Can you walk us through how your BESS performs during power outages or in remote, off-grid areas?

Battery systems, especially when used with Solar, can significantly reduce the cost and carbon footprint of using diesel generators (DG). DG abatement is a well-established use case for batteries globally.

In India, the cost of generating electricity from DGs is about INR 30-35 per unit, whereas with the current storage costs, it is about INR 10-12 per unit (including the cost of electricity used from the grid for charging). This represents a significant saving, and from an operational standpoint, it also eliminates the need for handling diesel, reducing noise and air pollution at the site.

In remote or off-grid areas the BESS is usually coupled with a Solar plant and intelligent inverters are used which balance the requirements of the load with the power generation during the day and at night support the load by discharging the battery. The EMS which controls the overall system also adapts to variability in the solar generation and takes charging / discharging related decisions accordingly to ensure the maximum up time.

You offer systems that range up to 1 MWh in size. What kind of businesses or institutions typically use your BESS, based on its various sizes?

We serve requirements of up to grid-scale BESS, which may run into a few hundred MWh.

• Small warehouses or commercial offices typically need up to 100 kWh of storage, and the dual purpose is to ensure uninterrupted supply and shave off the cost of power during peak tariff hours.

• Medium-sized manufacturing units such as food processors, textile mills, etc, need storage capacity of up to 250 kWh, and here the purpose is either to reduce power costs or increase the size of their captive solar plants, which are currently restricted due to net metering or contract load-related restrictions.

• Currently, most businesses require systems of less than 1 MWh; therefore, our C&I (Commercial & Industrial) storage solutions are sized accordingly.

• Lastly, larger manufacturing or process industries with sanctioned loads of 5 MVA to 25 MVA typically require storage systems of MWh scale (1 MWh to 5 MWh). Their primary objective is to reduce the cost of power and they use storage to achieve it by storing solar power during peak solar hours and discharging it during peak tariff hours or peak shaving i.e. using the battery to support peak loads which allows them to reduce their contract demand charges or storing solar power from their open access plants in states where energy banking is highly restricted.

What safety features are built into your BESS products to help prevent overheating, fires, or other failures?

Our BESS products comply with international standards, such as UL9540, NFPA 855, NFPA 68, and NFPA 69, which have stringent requirements regarding the prevention and containment of failures. The prevention-related safety features include a liquid cooling system, which provides highly targeted thermal management at the cell level such that the temperature differential across the 4,992 cells in a container is less than 4 to 5 degrees.

Each of the 4,992 cells is continuously monitored through a 3-tier BMS system and there are isolation devices at a pack, rack and container level. The cells also have vents to rapidly dispense gas build-up and prevent any explosion. In terms of containment, as the pack is compliant with UL9540, there is no fire or explosion even in the case of a thermal runaway event inside a pack. The container is equipped with smoke and fire detectors for early warning and includes aerosol and water dispensers for containing fire. The container itself has conflagration vents (emergency relief valves) which can safely vent gases, thereby avoiding any explosive gas build-up. The detection systems provide an early warning through a strobe light so that nearby personnel can safely evacuate the site.

You’re exploring new technologies like sodium-ion batteries and smarter energy management software (EMS). How might these innovations shape the future of energy storage products?

About Sodium-ion Battery Technology

The Sodium-ion family of chemistries opens up fascinating possibilities for countries like India, which lack local access to critical minerals. The absence of critical minerals could result in a significantly lower cost compared to that of lithium-ion-based chemistries. Sodium-ion batteries are less prone to thermal incidents, can have a significantly longer cycle life, support high charging and discharging rates and have superior extreme temperature performance.

They do have lower energy density compared to Lithium-ion, which may restrict their usage primarily to stationary applications.

We see Sodium-ion opening up many interesting use cases in India.

• Firstly, as they support high charging and discharging rates, they could be a highly cost-effective solution for short backup applications at C&I, as well as ancillary services for the grid (black start, frequency support, VAR support, etc.). Due to the inherent limitations of LFP (the chemistry of choice today for grid-scale storage), the minimum system size of storage is about 2-3 times higher than the actual backup required to ensure the charging/discharging rate is restricted.

• Secondly, for mobility applications where space is less of a constraint (e.g., commercial 3W, tractors), sodium-ion batteries can support fast charging without any specialised cooling requirements, which improves system reliability and reduces the need for specialised chargers.

• Lastly, most grid-scale BESS deployments are likely to be in states like Gujarat and Rajasthan, which have wide diurnal temperature ranges and Sodium-ion-based BESS systems can outperform LFP as they require lower temperature management, resulting in lower auxiliary losses and higher round-trip efficiencies, which can significantly boost the project IRR.

About EMS

Our effort on the Energy Management System (EMS) side is to serve three important objectives.

• Firstly, provide customers with an Indian solution which takes care of cybersecurity concerns.

• Secondly, help customers stay on top of the rapidly evolving Indian grid code, which, unlike in Europe or the US, has not matured fully yet and is likely to have significant variations due to India-specific context (e.g., increasing share of renewables, mitigation of T&D losses, etc).

• Thirdly, we expect Indian customers (C&I users, transmission companies, DISCOMs, IPPs etc) to have the need for supporting multiple applications (application stacking in industry parlance) with the same storage asset. This requires a versatile EMS to manage the performance under each application in a safe manner while adhering to the grid requirements.

Also Read: Decode : Chapter 3 – India’s Energy Storage Journey