CMBlu and MANN+HUMMEL Partner on Organic Flow Batteries

March 28, 2019 by Scott McMahan

CMBlu Energy AG and MANN+HUMMEL GmbH have agreed to jointly develop and industrialize energy converters for organic redox flow batteries. The goal of both partners is to support electric mobility through the development of the charging infrastructure and offer a sustainable and highly cost-efficient storage technology for a energy storage. CMBlu Energy's Organic Redox Flow batteries are currently in a prototype stage.

The Organic Flow Battery System

The idea for redox flow batteries with organic electrolytes derived from lignin (‘Organic Flow') was conceptualized in 2011, and since 2014, CMBlu has undertaken intensive research and development of the technology.

These batteries primarily consist of two tanks of liquid electrolyte and an energy converter, which has a large number of adjacent rows of cells and is therefore also referred to as a battery stack. The liquids are pumped through the battery stacks and are charged or discharged as required.

The technology that CMBlu developed has now reached the prototype stage. The further development and industrialization of the battery stack is regulated under the terms of the long-term cooperation agreement with MANN+HUMMEL.

For this purpose, MANN+HUMMEL has created a spin-off named i2M GmbH (innovation-to-market), which is dedicated to the development and commercialization of innovative technologies.

In the next step, MANN+HUMMEL intend to build a complete production line in a European plant. CMBlu will undertake special pilot projects with reference customers in the next two years. Then, starting in 2021, CMBlu plans to market the first commercial systems.

The Organic Flow Battery Stack

Similar to the principle of traditional redox flow batteries, CMBlu's Organic Flow Batteries store electrical energy in aqueous solutions of organic chemical compounds derived from lignin that are pumped through the energy converter, such as a battery stack. Unlike conventional batteries, flow batteries can scale the capacity and electrical output independently. A higher number of stacks multiplies the output.

On the other hand, the capacity of the battery is only limited by the size of the tanks. This simple way of increasing capacity allows flexible customization to take into account the respective application. For example, solar power can be stored for several hours and then fed into the grid when the sun goes down.

In order to achieve cost-effective volume production, the most critical components in the stack were adjusted to the organic electrolyte. In this process, almost the entire value chain for the stacks can be supplied locally. According to CMBlu, the production process and sourcing does not depend on imports from other countries. The battery stacks also do not require rare-earth metals or heavy metals.

Moreover, the aqueous electrolytes in the system are not combustible or explosive and can be used safely.

Variety of Applications in the Grid

Organic Flow Batteries are suitable for numerous application areas in the power grid including the storage of power from renewable energy generation or the balancing of demand peaks in industrial companies.

An additional application is the technology's use in the charging infrastructure required for electric mobility. The batteries could enable a buffer storage to relieve power grids. This buffer storage would not have to be upgraded for additional loads.

The organic flow batteries could enable simultaneous fast charging of electric vehicles.

Ultimately, CMBlu says that a decentralized charging network for electric vehicles will only be possible with a high performance and scalable energy storage.

Nature as a Model for Energy Storage

"Our concept is based on the mode of energy in the human body. In the citric acid cycle the body also uses a redox reaction of organic molecules. We have now succeeded in applying this principle to large-scale storage of electrical energy. For this purpose we use the mostly unused resource of lignin, which is readily available in unlimited quantities and accrues in amounts of millions of tons annually in the pulp and paper industry. Our technology enables a very large and cost effective energy storage system. The battery stack is the core of the system and requires the highest quality and process reliability in the production process. MANN+HUMMEL is a perfect partner in the industrialization process.", explains CMBlu CEO Peter Geigle.

"In line with our strategic initiatives to promote clean air and clean mobility, we were very interested in the technology of CMBlu right from the start. We believe that the expertise, product range and experience of MANN+HUMMEL offer considerable advantages for the production of battery stacks in order to quickly achieve the required performance level and make the technology cost-effective. The manufacture of electrolytes includes a number of filtration steps, which MANN+HUMMEL performs using new special membranes. This technology further expands our product range and at the same time contributes to build the infractruture needed for electric vehicles", says Charles Vaillant, Chief Technology Officer at MANN+HUMMEL. "This also enables us to make a significant contribution towards a sustainable energy transition globally."