ElectriStor™ Technology Platform
WattJoule’s core innovations and IP portfolio are embodied in four critical, integrated, proprietary technology components that comprise the ElectriStor™ platform as shown and detailed below. Our technology is protected by a growing IP portfolio of patents, patents pending and trade secrets. We have also acquired and exclusively licensed IP as part of our portfolio. WattJoule’s ElectriStor™ flow battery technology is applicable to a broad range of flow chemistries based on both vanadium and non-vanadium chemistries.
WattJoule Core Material Set
WattJoule has developed a core set of proprietary materials to enable higher performance, lower cost, long life, scalable supply and market defensibility. These materials incorporate innovations in the use of advanced nano-based and engineered composite materials. Core materials are our electrolyte active materials and additives; stack separator, electrode, bipolar plates, and flow frames; and multiple coatings and catalysts. Working with our strategic partners, we have developed readily scalable manufacturing processes that utilize in-place manufacturing infrastructure capability with little added capital investment.
WattJoule Liquid Electrolyte
The electrolyte is the energy storage medium of our system. The ElectriStor™ electrolyte family utilizes advanced chemistries that work in close conjunction with our core material set and energy conversion stack. Today’s electrolytes for vanadium redox batteries have low energy density, a restricted temperature range requiring active cooling equipment, and need costly high-purity vanadium. In contrast, WattJoule’s liquid electrolyte stores more energy per liter, requires no expensive cooling, and reduces the amount, purity and cost of vanadium over successive generations. We have also achieved a formulation that has demonstrated long-term stability and durability over 3000 cycles and counting. There are no known mechanisms that can cause our electrolyte to deteriorate over time.
Improved energy density means less liquid is needed to store an equivalent amount of energy. This means a much-reduced system installed cost and footprint. Improved temperature range means no need for air conditioning, chillers and associated equipment. This means a much lower system capital cost, operating cost and footprint. By eliminating this active cooling requirement overall system efficiency is improved for long term operating savings.
Vanadium is the active material in the electrolyte that stores the energy and is the primary electrolyte cost driver. In Generation 1, WattJoule has achieved both a better utilization of this material and has invented a better way to use a lower purity grade vanadium. The net effect is reduced cost. In Generations 2 and 3, we are developing a pathway to advanced chemistries that will lower electrolyte cost even further.
Electrolyte comprises a major part of the ElectriStor™ system and ours is inexpensive to make. We make our electrolyte with commonly used industrial grade chemicals within an existing volume supply chain. Working with our strategic partners, we have developed a simplified electrolyte manufacturing process that utilizes in-place manufacturing infrastructure in use by today’s chemical industry. No ultra-expensive GigaFactory is required. We can figuratively flip a switch and be producing over 100 MegaWatt Hours of energy storage equivalent liquid in a matter of months.
WattJoule Energy Converter Stack
The actual conversion of electrical energy to electrochemical energy, and vice versa, is accomplished in a redox flow cell. Arrays of these cells are built into a stack to handle larger and more usable quantities of electrical power. This stacked array of cells is referred to as an energy converter stack, or simply a stack.
WattJoule stacks are a critical component of the ElectriStor™ system. Our stacks are based on our Core Material Set (described above), especially the electrode, separator and bipolar plate components. Our stack incorporates a number of design innovations that, together with our Core Material Set, translate to higher power density, higher conversion efficiency, lower electrical impedance and lower cost. WattJoule stacks are also optimized for use with WattJoule electrolyte to insure durable, long-term operation.
A major feature of the WattJoule stack is its ability to handle considerably more power than what is normally supported by state-of-the-art stacks of the same size. This is referred to as higher “power density.” Put another way, for any given power rating, WattJoule stacks are significantly smaller, by a 6X factor in size! This means far less material use and cost savings.
WattJoule stacks are engineered to be highly durable and easily manufactured. How do you scale manufacture megawatts of stacks with high reproducibility? The answer is design-for-manufacture and robots. WattJoule has been working with its contract manufacturing partners to ensure that the volume transition from manual to fully automated robotic stack assembly will be seamless and cost effective. We project the ability to rapidly scale into megawatts of stack production with a relatively small capex investment. This means no ultra-expensive GigaFactory required!
WattJoule System Design
Our ElectriStor™ system is designed and built as a complete DC modular system with the electrolyte, tanks, stacks, pumps, heat exchanger, and proprietary system-level controls. The system is designed to be assembled with minimal labor and components.
System-level controls consist of an integrated software and sensor package that implements how the entire system is charged, discharged, and operated in a manner that insures safe, efficient, long-term reliable operation. WattJoule has developed innovative sensor technology to solve measurement problems unique to flow batteries yet fundamental to their proper long term operation.
On the system software front, WattJoule provides two levels of software. First, at the Battery Management System (BMS) level, software is embedded in the ElectriStor™ electronic control system that comes bundled with the hardware storage module, to control module specific operation. This level of software also provides clustering of ElectriStor™ modules to form large arrays of storage systems for large storage capacity requirements.
The second level is the all-important Energy Management System (EMS) level. This is the software that sits between ElectriStor™ and the utility electrical grid, and typically other systems, e.g. a solar array, a full electrical service for an entire building, and perhaps even another storage system. At the EMS level, WattJoule can provide a proven third-party OEM EMS software that has been pre-integrated/pre-tested with both our ElectriStor™ system and select AC-DC power conversion equipment. These proprietary software components make OEM integration fast, cost effective and surprisingly flexible as delivered. Of course, we can always work with OEMs to integrate their proprietary EMS software with ElectriStor™ BMS level software, if they choose that option. Or alternatively, we can assist with the integration or other third-party EMS level software packages.