Li-ion battery technology is maturing, but is a relatively new technology compared with lead-acid batteries and is a significant improvement as it offers high energy density, high efficiency, long-cycle life, and lower maintenance. These batteries work on an electrolysis model with lithium metal oxide cathode and graphitic carbon anode placed in an electrolyte made up of lithium salts dissolved in organic carbonates.

Listed below are the key technology trends impacting LIBs for underwater application, as identified by GlobalData.

Replacement of lead-acid batteries in diesel electric submarine propulsion

Lead-acid battery (LAB) technology, even with its drawbacks in power and energy density, has survived a century as a source of stored energy for main propulsion or as stand-by batteries for submarines. However, increased endurance and speed demands have stimulated the development of a new generation of energy storage technology, based on mature Lithium-ion battery (LIB) technology. The LIB system for submarines could be a milestone in the industry. Compared to the well-known lead-acid battery, the lithium-ion battery requires very little maintenance and has a longer service life.

Key submarine designers such as Naval Group, TKMS, and Saab have conducted extensive research into the use of LIBs on future submarine designs. They are expected to release their LIB-powered submarine designs in the near future.

Graphene coating for LIBs

The economies of energy storage in a wide range of applications, coupled with the falling cost of systems, would likely result in the rapid growth of battery energy storage solutions. Lithium-ion batteries are emerging as crucial for energy storage. The increasing growth of LIB-powered electric vehicles resulted in advancements in lithium-ion technologies and a steady decline in the prices of lithium-based batteries.

While Li-ion batteries have gained more popularity than other battery energy storage technologies, the introduction of graphene could revolutionise the way energy storage technology is utilised, which would enhance its market potential. Graphene is nothing but a carbon-based material, which is merely one atom thick and can be used to make batteries, which are lightweight, durable and applicable in high capacity energy storage, and they charge rapidly.

Recently, researchers from the Samsung Advanced Institute of Technology (SAIT) and Seoul National University’s School of Chemical and Biological Engineering collaborated to design a graphene coating for Li-ion batteries to enhance charging speeds by five-fold and increase battery capacity by making it 45% more energy-dense.

Improved battery storage technologies

Battery storage is expected to play a critical role in the energy transition in the fields of electric mobility and be a vital component offering flexibility and supporting variable renewable energy to the power grid.

Many battery chemistries remain viable, but advancements in Li-ion have led to market dominance, covering 95–99% of market deployments in recent years. Much of this can be credited to Li-ion Nickel-Manganese-Cobalt (NMC) batteries, which have a right balance of energy density and power and comprise much of the present growth in battery electric vehicles in the automotive sector. Brands such as LG and Samsung are predominantly NMC batteries. Tesla advertises its battery as a Nickel Cobalt Aluminum (NCA) battery. As these batteries get cheaper, they become more viable for long-duration applications by simply stacking them in larger quantities. Energy density in Li-ion iron phosphate (LiFePO4) batteries has also been increasing over time with similar cost declines, making LiFePO4 also a viable candidate for both short and long duration functions.

Changing the battery chemistry type to Li-S, Li-O, or Mg-Ion has the potential to improve energy density and ensure faster and more charging cycles. Such improvements are especially crucial for mobility applications.

However, new types and chemistries are all challenged with competing with the ever decreasing cost of now-conventional, now-incumbent Li-ion batteries based on NCM/A chemistries. Today, these batteries have achieved low cost and increasing energy density not by leap-frogging their competition with technological breakthroughs, but with persistent and straightforward engineering optimisation of their production methods, tooling, speeds, and efficiency.

Longer cycle life

A typical lithium-ion (li-ion) battery pack, after a few thousand charging cycles, must be exchanged for a new one. But with the recent advancement in technology, these used batteries can go on to enjoy second, third, and even fourth lives. At present, most telecom tower operators and utility companies are leveraging second-life batteries to optimise their operational costs.

Effective management of the battery life cycle is potentially the key to the future of underwater applications. Original equipment manufacturers (OEMs) will focus on designing efficient thermal management systems and programming usage controls to enhance the battery cycle’s life.

Fast charging Li-Ion batteries

The present market of mobile devices and electric transportation technologies is undergoing expansion in terms of the need for high energy density and safe rechargeable batteries.

There are several types of research for Li-ion batteries to push the boundaries of rate capability of Li-ion cells. Ever-higher charging rates are especially desired in the electric vehicle (EV) industry, where it is believed that charging rates that start to rival the refuelling time of internal combustion vehicles will mitigate so-called ‘range anxiety’ and push the widespread adoption of EVs.

This is an edited extract from the Lithium-ion Batteries for Underwater Applications – Thematic Research report produced by GlobalData Thematic Research.