StorEn Technology is developing a new generation of vanadium flow batteries. Building upon the demonstrated strengths of vanadium flow batteries such as durability and sturdiness, StorEn R&D activities focus on improving the electrical efficiency of the stack, the energy density of the electrolyte and the module. StorEn solutions can deliver superior performances at a lower cost and fulfill market demand for efficient and cost-effective energy storage.
A vanadium flow battery is a type of rechargeable battery in which the energy is stored chemically in a liquid electrolyte contained in two tanks, unlike conventional batteries that store their reactive materials within their cells.
Each tank contains a different electrolyte formulation: one for the positive reaction; the second one for the negative one. The liquid electrolytes are pumped through the cells, generally grouped together in a block known as stack or cell stack. The two flows of electrolyte never mix together as they are separated in the cells by an extremely thin membrane that only allows selected ions to flow through. The cells also contain an array of very stable porous carbon electrodes, where critical reactions take place.
In each side of the stack, the cells are connected electrically in series by bipolar plates, i.e. conducting plates that have positive electrolyte on one side and negative on the other. Therefore, the stack voltage (V) is the sum of the voltage of the individual cells. E.g. a 10-cell stack has ten times the voltage of a single cell.
The stack power (in kW) is also the sum of each cell power. The power of each cell is governed by the battery chemistry, temperature and cell dimensions, among others.
However, the energy (in kWh) of the battery is dictated by the amount of electrolyte in the tanks. Higher volumes of electrolyte will store more energy, and provide the same power for longer, thus increasing the power ratio of the battery.
Therefore, flow batteries are unique in being able to independently scale the energy and the power to meet the demands of any given application.
Vanadium flow batteries demonstrated some key fundamentals that are intrinsic to the technology such as:
- over 15,000 cycles (3X longer than lithium) or 15-20 years of operation
- scalable by just increasing the quantity of electrolyte stored in the tanks
- no ghost-effect due to recharging when not fully discharged
- absence of self-discharge even if left unused for long periods of time (as opposed to lithium batteries)
- no damage if left completely discharged for long periods of time
- exceptional sturdiness if overcharged up to a 400% and can easily resist to charge and discharge tensions up to twice the nominal one
- the large availability of vanadium
StorEn R&D activities will focus on improving the electrochemical performance of the modules. In details, StorEn proprietary design will grant:
- Improved electrical performance and power density of the stack due to the use of innovative materials in the stack. This will grant a considerable reduction in the size and cost of the power side of the batteries
- Innovative formulation of the electrolyte to increase the modules’ energy density. This will reduce the size, weight and cost of the batteries
- Improved module design to reduce internal components. This will extend maintenance intervals and reduce manufacturing and maintenance costs