EvolOH (High-speed manufacturing of alkaline water electrolysis stack for low-cost green hydrogen production)

EvolOH, an American hydrogen energy startup founded in 2020, specializes in low-cost and high-speed manufacturing of alkaline water electrolyzers for the production of green hydrogen. The company has built the highest throughput electrolyzer stack factories in the world.

Challenges: green hydrogen

Green hydrogen energizing the path to net zero

Hydrogen (H₂) is a crucial component in the production of ammonia, which is a key ingredient in many fertilizers, plastics, and other essential products. The majority of the world’s hydrogen (over 60 million tons) is produced via steam methane reforming (SMR) process. This process requires a significant amount of energy input and contributes about 2% of global carbon dioxide (CO₂) emissions. The SMR process emits between 5 and 9 tons of CO₂ per ton of hydrogen produced.

Hydrogen can also be produced through water electrolysis. Water electrolyzers typically include alkaline water electrolyzer (AWE), proton exchange membrane water electrolyzer (PEMWE), and solid oxide electrolysis cells (SOEC). If these electrolyzers use electric power from renewable energy sources, such as nuclear, solar, and wind, the hydrogen produced is referred to as “green hydrogen”. Green hydrogen can decarbonize hard-to-abate industries, such as steel manufacture, long-distance transportation, shipping, and aviation.

Green hydrogen is crucial for a carbon-neutral world.

Green hydrogen cost

The levelized cost of hydrogen (LCOH) is a variable that indicates how much it costs to produce 1 kg of hydrogen, taking into account the estimated costs of the investment required and the cost of operating the assets involved in its production.

Green hydrogen is not yet cost-competitive with SMR-produced hydrogen. The LCOH of gray hydrogen through SMR without carbon capture is below $1/kg, even assuming a natural gas price at $3.50/MMBtu. The LCOH of blue hydrogen produced through SMR with carbon capture ranges from $1.40/kg to $2.55/kg, depending on the technology used. The LCOH of green hydrogen is currently in the broad range of $3 – $7/kg, depending on several factors such as location, technology, and the cost of renewable energy.

However, it is anticipated that the LCOH of green hydrogen will decrease, making it cost-competitive with SMR-produced hydrogen. During the past two decades, the levelized cost of electricity (LCOE) for newly commissioned installations of PVs and onshore and offshore wind power decreased by 88%, 68%, and 60%, respectively. Technological advancements are anticipated to play a significant role in reducing the LCOH of green hydrogen.

Green hydrogen cost reduction

Modern alkaline water electrolysis currently provides the lowest LCOH among the three types of electrolyzers (proton exchange membrane water electrolysis and solid oxide electrolysis cells). They are highly efficient and able to handle the intermittent loads associated with renewable energy sources.

The diagram below depicts the working mechanism of a typical alkaline water electrolyzer.

Working mechanism of a typical alkaline water electrolyzer.
Working mechanism of a typical alkaline water electrolyzer.

Alkaline water electrolyzer has two electrodes operating in a liquid alkaline electrolyte solution of potassium hydroxide (KOH) or sodium hydroxide (NaOH). A diaphragm separates the electrodes, prevents the product gasses from crossing, and transports the hydroxide ions (OH⁻) from one electrode to the other.

Even though the government is supporting hydrogen projects with thousands of megawatts of power, the production of electrolyzer stacks is still only a few hundred megawatts. This difference makes it harder for hydrogen to be used as a base for new industries. To lower the price of green hydrogen and meet the demand, electrolyzer production needs to go up by many orders of magnitude.

EvolOH Technology

EvolOH develops a high-speed manufacturing of alkaline water electrolysis stack. Electrolysis cells are constructed with polymer sealants that cure rapidly within seconds. This facilitates the integration and stacking of electrolysis cells in a continuous production line. EvolOH is capable of producing over 1,000 megawatts of electrolyzer stacks in a year. EvolOH’s technology not only reduces the cost of the water electrolysis stacks but also enables their rapid deployment.

EvolOH electrolysis stack structure

The diagram below depicts the EvolOH’s electrolysis cell stack and fluid flow within it.

EvolOH electrolysis cell stack and fluid flow within it
EvolOH electrolysis cell stack and fluid flow within it.

The electrolyzer stack comprises a stack of electrolyzer cells (arranged along a z-axis), stack end units, and a compression system (not shown).

As shown in the right diagram, each electrolysis cell comprises:

  • a membrane
  • an anode flow field with an anode
  • a cathode flow field with a cathode
  • a bipolar plate assembly

As shown in the middle diagram, when these cells are stacked on top of each other, the water and hydrogen distribution windows in each cell line up along the z-axis. This forms water (along the x-axis) and hydrogen (along the y-axis) plenums for distributing and collecting process fluids to and from individual cells in the cell stack.

The water delivery windows are positioned adjacent to the leading edge of the anode flow field. This design allows the electrolysis stack to have substantially equal resistance to water flow, equal temperature rise, and equal exit oxygen fraction at a given operating voltage. This makes EvolOH’s electrolysis stack scalable.

How EvolOH performs high-speed manufacturing of electrolysis stack

EvolOH develops a continuous production line designed for high-speed manufacturing of the electrolysis stacks. The continuous production line includes high-speed manufacturings of:

  • bipolar plate assembly
  • membrane
  • electrode flow fields
  • assembly of electrolysis cells
  • assembly of electrolysis stack

The above processes are described in detail below.

High-speed manufacturing of bipolar plate assembly

The diagram below depicts the structure of EvolOH bipolar plate assembly.

EvolOH bipolar plate assembly (ref. US20230374674A1) 
EvolOH bipolar plate assembly (ref. US20230374674A1).

The bipolar plate assembly comprises a bipolar plate, a hydrogen seal, a fluid distribution frame, and a water seal.

For an alkaline electrolysis cell, the bipolar plate comprises stainless steel, nickel, Inconel, or Fecralloy. Such bipolar plates are also covered with an appropriate coating, such as platinum, nickel, or carbon.

A hydrogen seal or water seal comprises a compatible elastomeric or polymeric material, such as silicone, polyurethane, polyolefin, urethane, acrylate, vinyl, or butyl.

The fluid distribution frame is constructed of a relatively rigid plastic material. For example, it may be made by injection molding polycarbonate or other elastomers of suitable properties.

The diagram below depicts the high-speed manufacturing of the bipolar plate assembly.

High-speed manufacturing process of EvolOH bipolar plate assembly (ref. US20230374674A1) 
High-speed manufacturing process of EvolOH bipolar plate assembly (ref. US20230374674A1).

The manufacturing process comprises the following steps:

  1. Bipolar plate is loaded into the assembly line.
  2. Hydrogen seal is applied in an uncured state to the bipolar plate using an appropriate high-speed application method, such as screen printing.
  3. Fluid distribution frame is then aligned to the bipolar plate and pressed onto the hydrogen seal. The hydrogen seal is cured using a rapid curing method, such as ultraviolet light curing.
  4. Water seal is applied to the top of the fluid distribution frame in an uncured state using an appropriate high-speed application method, such as screen printing.
  5. The water seal is cured using a fast curing method, such as ultraviolet light curing.

High-speed manufacturing of membrane

The diagram below depicts the high-speed manufacturing of applying cell internal seal to the membrane.

High-speed manufacturing process of applying EvolOH cell internal seal to the membrane.  (ref. US20230374674A1) 
High-speed manufacturing process of applying EvolOH cell internal seal to the membrane.  (ref. US20230374674A1).

This manufacturing process includes the following steps:

  1. A roll of membrane or catalyst coated membrane web is loaded onto an unwinding station designed to hold the web flat under a known tension and able to move along a direction.
  2. An internal seal is then applied directly to the membrane using an appropriate high-speed application method, such as screen printing.
  3. The internal seal is then cured using a fast ultraviolet light curing method.
  4. The web is advanced to a position where discrete membrane-gasket assembly pieces are cut from the roll.

High-speed manufacturing of electrode flow field

The diagram below depicts the high-speed manufacturing of electrode flow field components.

High-speed manufacturing process of EvolOH integrated electrode flow field component (ref. US20230374674A1)
High-speed manufacturing process of EvolOH integrated electrode flow field component (ref. US20230374674A1).

The manufacturing process includes the following steps:

  1. A roll of porous substrate web is loaded onto an unwinding station designed to hold the web flat under a known tension and able to move along a direction. The porous substrate comprises iron, nickel, chromium, stainless steel, Inconel, or carbon. The porous substrate is also coated with other materials, such as platinum, carbon, titanium nitride, PTFE, or another corrosion-inhibiting layer.
  2. The porous web is calendered through a set of rollers to create desired surface characteristics on both sides of the web.
  3. An electrode material is then coated on the surfaces of the calendered web with a suitable method, such as doctor-blade coating or spray coating.
  4. The electrode coating is annealed to promote bonding to the substrate and convert into an active electrode.
  5. The electrode web is then placed adjacent to a second roll of porous substrate. This porous substrate meets functional requirements for a fluid flow field, rather than an electrode.
  6. The electrode web is laminated to the fluid flow field web through a set of rollers.
  7. Following the lamination step, the unitized electrode flow field web is cut to discrete piece parts of the appropriate size for integration into an electrolysis cell.

High-speed manufacturing of electrolysis cell

The diagram below depicts the high-speed assembly of a unitized EvolOH electrolysis cell.

High-speed manufacturing process for assembling a unitized EvolOH electrolysis cell (ref. US20230374674A1)
High-speed manufacturing process for assembling a unitized EvolOH electrolysis cell (ref. US20230374674A1).

The assembly process includes the following steps:

  1. The bipolar plate assembly is loaded into an assembly line moving along a direction.
  2. A cathode electrode flow field is placed into the cavity of bipolar plate assembly.
  3. The resulting sub-assembly is advanced to a position where a membrane gasket assembly (membrane with internal seal) is placed into the cavity of the bipolar plate.
  4. The resulting sub-assembly is further advanced to a position where an anode electrode flow field is placed into the cavity of the bipolar plate.
  5. The resulting unitized cell assembly is further processed to ensure that all components are properly positioned within bipolar plate assembly.

High-speed assembly of electrolysis cell stack

The diagram below depicts the high-speed manufacturing process for assembling electrolysis cells into a stack.

High-speed manufacturing process for assembling EvolOH electrolysis cell stack (ref. US20230374674A1)
High-speed manufacturing process for assembling EvolOH electrolysis cell stack (ref. US20230374674A1).

The rotary stacking station comprises stations for loading non-repeating components, placing and aligning cells, compressing and quality checking the assembly, and unloading the final stack. The rotary stacking station allows multiple operators to perform actions simultaneously, thereby accelerating the throughput of finished stacks and enabling high-speed stack production.

A production system like this can handle 1,000 electrolysis stacks and corresponding 300,000 cells every year, which is equal to 1,000 megawatts of electrolyzer stacks. This production capacity can reach a stack time of about 20 seconds per cell and 1.8 hours per stack for a production shift that works 1,750 hours per year.

More significantly, this production system is scalable.

EvolOH Patent

  • US20230374674A1 Scalable electrolysis cell and stack and method of high-speed manufacturing the same
  • US20230287587A1 Water electrolyzer

EvolOH Technology Applications

  • Green hydrogen mega-projects

EvolOH’s electrolyzers are designed for high-speed, low-cost manufacturing, making them an ideal choice for developers announcing green hydrogen mega-projects. The company’s electrolyzers provide the lowest capital and operating costs for green hydrogen production, making them a cost-effective choice for these large-scale projects.

  • Manufacturing of electrolyzers

EvolOH’s technology also has applications in the manufacturing of electrolyzers. The company is building the world’s largest green hydrogen electrolyzer manufacturing plant in Massachusetts, known as EvolOH’s Manufacturing Center of Excellence. This facility will have a capacity for up to 3.75 GW per year of electrolyzer stacks when fully operational. Additionally, EvolOH plans to expand its manufacturing capabilities with a second plant, projected to break ground in 2026, aiming for an annual capacity of 15 GW for electrolyzer stacks.

EvolOH Products

Nautilus electrolysis stack

Their primary product is the Nautilus series alkaline water electrolyzer stacks, which are designed for high-speed, low-cost manufacturing and secure supply chains.

Nautilus series provide the lowest capital and operating costs for green hydrogen production when operated using pure water. With power ratings up to 5 MW (2 tons per day) for a single stack, and 50 MW (20 tons per day) for a single containerized module, EvolOH’s scalable stacks are designed for large-scale power-to-hydrogen facilities.

EvolOH Funding

EvolOH has raised $1.12M over 4 rounds. EvolOH’s latest funding round was a Grant round on September 15, 2022.

EvolOH Investors

EvolOH has raised funding from several investors, including:

EvolOH Founder

Jimmy Rojas is Founder.

Taylor Huff is Co-Founder.

EvolOH CEO

Jimmy Rojas is CEO.

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