One of the greatest challenges facing the energy industry today is finding economical ways of storing energy that is available quickly. Some solutions for energy storage, such as hydroelectric and compressed air, have existed for many years but often involve facilities that are expensive to build and maintain. Electrochemical energy stored in batteries is becoming a more popular solution because of a relatively simpler deployment, the attractiveness of instant power when needed, and the power of smart software to drive it. The promise of battery-based energy storage has been described as having the same level of importance as the introduction of refrigeration in the food supply¹.
Grid-scale energy storage systems powered by batteries are compelling for renewable energy as a way to manage inherently intermittent energy sources, and have already been deployed by utilities in California, Hawaii and elsewhere. Wind energy, for example, is becoming increasingly more widespread, now estimated to power over 15 million American homes². Having the flexibility of storing energy in a grid-based battery array allows utilities and operators to quickly deploy this energy during peak hours. Battery solutions can thus preclude the need to construct and maintain so-called “peaker plants”, which run on natural gas and are spun up on demand.
Lithium-ion is the battery technology of choice for most consumer electronic and electric vehicle (EV) applications, which continues to drive down costs. It’s expected that by year-end, the cost per kilowatt hour will go below the all-important threshold of $100, making lithium-ion even more attractive as a technology for powering transportation in particular.
Grid-scale energy storage, however, poses unique requirements. In an EV, battery size and capacity are paramount since they greatly influence weight and thus driving range (cost is also important, but to a lesser degree since EVs are still priced at a premium). Not surprisingly, these factors have largely driven lithium-ion advancement in recent years. Conversely, for grid-scale energy storage, the major factors include cost and overall lifespan, since typical deployments are expected to last decades and need to compete with stable and cheaper natural gas solutions. While the cost has gone down, lithium-ion batteries are not designed to last for up to 20 years without being recycled and replaced multiple times, which drives up costs considerably.
Lithium-ion batteries are a focus for research, since they are quite flexible in what materials can be used as the electrode, driving a downward trend in manufacturing costs. Electrical energy is traditionally stored in lithium compounds, such as lithium cobalt oxide (LCO), but this is more expensive than lower-cost alternatives that are being explored, such as using a mixture of nickel, cobalt and aluminum (NCA), or nickel, cobalt and manganese (NCM).
There are a number of other battery technologies being used and explored for grid-scale energy storage, including the following:
- Sodium sulfur batteries have shown promise in the energy storage sector because of their higher energy density compared to lithium-ion, and longer cycle life. These batteries operate at high temperatures (300-350°C) in order to keep the sodium and sulfur electrodes in liquid form. The discharge process creates sodium polysulfide, which is highly corrosive. Because these batteries are deployed in larger sizes, they are less expensive to maintain vs. thermal management of many smaller units.
- Sodium nickel batteries are a lower-temperature alternative and use a ceramic electrolyte composed of Sodium Tetrachloroaluminate (NaAlCl4) with Na+-beta-alumina. In place of nickel, the electrode is made of nickel chloride which forms a molten salt when dissolved in the sodium aluminum chloride. This battery technology is less prone to corrosion, with life spans that reportedly can last up to 3,000 cycles and 10 years.
- Nickel-Cadmium (NiCd) rechargeable batteries are known for their durability and are typically used in heavy industrial settings. Due mostly to their higher cost, they have largely lost market share to lithium-ion and lead acid batteries. Their main advantage for energy storage is their ability to withstand high discharge rates without impacting overall capacity.
- Flow batteries have the advantage of nearly unlimited capacity because ion exchange occurs through a porous membrane, while each anolyte and catholyte liquid is stored in its own respective tank, which can be of varying size. Even though this solution can be supported indefinitely with proper maintenance, the materials involved are more expensive than other solutions.
- Lead acid batteries enjoy one of the longest cycle lives, and this has improved even more in recent years. Since energy density is not as much of a concern for energy storage, lead acid batteries can compete on cost with lithium-ion and can tolerate conditions where the charge is not routinely restored to a full state. Lead batteries store energy as pure lead on the negative electrode and lead dioxide (PbO2) on the positive side, and use a liquid sulphuric acid compound. Lead batteries are the most sustainable of all battery technologies, since lead is the most efficiently recycled metal, with over 99% recycle rates in the U.S. and Europe.
Innovations that drive battery solutions in the coming years will come from both materials science and software: Both via more efficient mediums, particularly with lithium-ion, as well as from advances in intelligent software and cloud computing.
We strongly believe any industry driven by smart software will have a competitive advantage over legacy solutions. Applying the latest technology capabilities in machine learning to improve predictive analytics will in turn increase battery performance, reduce costs, and drive the overall growth of the energy storage market, which is expected to reach $26 billion in sales by 2022³.
PLI for Batteries works across a range of battery technologies
Peaxy Lifecycle Intelligence (PLI) for Batteries is a complete predictive battery analytics platform that leverages machine learning to deliver dramatic performance improvements across R&D, manufacturing and field operations.
PLI for batteries is the first cloud-based battery analytics software platform to deliver a unified data vision for battery development, manufacturing and deployment. Using a proprietary process, our enterprise-grade solution securely captures and stores the entire data value chain to create a single source of truth for serialized battery data, laying the foundation for high-fidelity digital twins and machine-learning driven insights.
- Degradation curves for each serial number in real time
- Optimization of charge / discharge regimes
- Tracking of ambient profiling and operating profiles to help tune optimal charge / discharge cycles
- We help operators work within the boundaries of complex battery warranty regimes
- We help lessors make sure they protect the long-term residual value of battery assets
View infographic below, also shared on LinkedIn: