Navigant Research Blog

Drones Paving the Way for Next Generation Advanced Batteries

— July 17, 2018

Unmanned vehicles (UVs), or drones, are becoming increasingly mainstream in several industries, but the underlying issue they face is determining what the ideal power-to-weight ratio should be for drones. The power-to-weight ratio is the metric that determines the amount of time the drone can operate on a single charge. For example, aerial drones typically have flight times of 10 to 30 minutes. Compounded with key functionalities like traction controls, guidance systems, sensors, cameras, data acquisition, data analysis, and cataloging, energy can be drawn from the battery quickly.

Advanced batteries provide inroads to solve this problem, and Navigant Research expects this market to reach $224.9 million in 2026 alone. Historically, the drone industry used nickel-cadmium batteries, but lithium ion (Li-ion) batteries immediately improved the performance of the vehicle because of their lighter weight and higher power/energy density. Still, current Li-ion batteries may not be ideal in high temperature, elevated pressure, or extreme weather environments. These batteries operate best within a 0º F to 45º F temperature range at atmospheric pressure. Any deviation from this could result in catastrophic failure.

As battery manufacturers are looking to bring their next generation technologies to market, particularly in the transportation sector, drones are looking to be an important early market. This is because they can be used in similar use cases (i.e., for traction and propulsion) at a smaller, less capital-intensive scale. They can also be engineered for use in extreme environments. This is an important consideration when developing vehicles used underwater or in aerospace applications.

Aerial Drones: The Ideal Market for Battery Cells?

SolidEnergy Systems, a Massachusetts-based company, manufactures a semi-solid lithium metal cell. The company reports that this is the lightest rechargeable battery cell in the world. With the ultimate goal of entering the EV market at scale, the company has determined that aerial drones are an ideal niche market to test the performance and scalability of its technology. SolidEnergy states that—compared to current Li-ion batteries—its battery can increase flight times to over an hour and that this is steadily improving. The company closed on a funding round of $34 million in late January. These funds will be used to help spur the current low volume sales and increase manufacturing capacity to further drive down the battery’s current $500/kWh costs.

UK battery manufacturer Oxis Energy also sees aerial, aerospace, and underwater drones as early markets for its lithium sulfur (LiS) batteries. Though the company is continuing to mitigate the characteristic polysulfide shuttle problem endured by LiS batteries, it has seen interest from several UV companies to develop its technology and eventually deploy in the coming months. Oxis notably secured a grant to develop a 425 Wh/kg cell for aerial drone technology for aerospace applications.

Oxis Energy LiS Cell Diagram

(Source: Oxis Energy)

Niche markets like drone technology will be vital in ensuring that improved advanced batteries are meeting their technology roadmaps and that these batteries are on track to help tackle the impending EV and energy storage system boom. Ensuring that the batteries improve the power-to-weight ratio, meet performance requirements, and are safe in extreme environments will be critical to their mass deployment. As these are proven, economies of scale will develop and rapidly drive down system costs, paving the way for inroads into new, highly profitable market opportunities.


BMS or Bust: Why Battery Management Systems Are Critical to the Industry

— July 3, 2018

Since the advanced battery industry is growing adjacent to other large industries such as EVs and energy storage, batteries must be equipped to perform effectively under dynamic environments. The battery management system (BMS) is an important component of this goal, as it is critical to determining the lifespan of the battery. Navigant Research believes that grid-facing energy management system software will be where the most innovation will occur in the advanced battery industry over the next several years, reaching $34.7 billion in 2025. Growth in the BMS industry will be similar.

What Is a BMS?

There is no clear definition of what constitutes a BMS, and the advanced battery industry has a fragmented interpretation as to what the system is supposed to do. Current standards do not adequately define BMS requirements; loopholes and conflicting literature exist across governing bodies. This has led to excessive supplier-driven standards developed from the bottom up rather than the top down.

A clear definition and list of attributes related to BMSs enable stakeholders to avoid confusion, add consistency across platforms, reduce complexity, increase safety, and reduce cost. Without a definition, the following can result:

  • Inefficient cell and system designs
  • Inconsistent requirements for cells, packs, and systems
  • Costs inflation on the cell and pack levels
  • Longer battery development timeline

Why Do We Need a BMS?

Voltage, current, and temperature are electrical constraints that are monitored from the outside of cells. This type of monitoring does not paint an accurate picture of the internal state and health of the batteries. Because of that, engineers tend to be conservative with how they design battery packs. Companies thus tend to be careful with how they market the use of the packs, and the full potential of the battery is rarely realized.

Navigant Research believes outlining BMS requirements should be the first step to fabricating a universal standard. There is no one-size-fits-all solution; BMS regulation requirements should broadly fall into three categories:

  • Electrical requirements: Voltage, current, system redundancy, state of health, and conversion interfaces
  • Physical requirements: Packaging, thermal management, and mechanical interfaces
  • Safety requirements: Cell and system, environmental, and end-of-life considerations

Companies are beginning to understand the importance of designing an effective BMS and are driving advanced battery researchers to push the limits of design and integrate into existing technologies. For example, Advanced Research Projects Agency-Energy (ARPA-E) awarded the University of Washington a $3.4 million grant to develop a BMS that uses internal advanced sensors to predict the physical state of the battery as a result of charging and discharging. This allows quick and accurate data to be used in decision-making surrounding how to control the battery to optimize its efficiency in real time.

Further, Imperial College London is working with its industrial partners to improve battery performance in EVs via a BMS. One project with Zap&Go, Codeplay Software, and PowerOasis aims to design an improved BMS that allows faster charging, enhanced power delivery, and longer vehicle battery lifespan.

Going forward, Navigant Research believes that battery hardware and software manufacturers should continue to look to improve technologies surrounding the BMS and advanced sensors. The BMS is not just software used to maintain state-of-charge and/or monitor state of health. Rather, it is an amalgamation of components, functions, and features that are necessary to meet electrical, physical, and safety requirements. Improving these functions will stretch the lifespan and use cases of the battery system, increase safety, and grow profit margins for electrochemical batteries.


Steady Improvements Crucial to Building Better Batteries

— June 28, 2018

As the quest for creating a better battery looms, advanced battery research firms and manufacturers are looking for the best ways to optimize their technologies to meet the energy storage applications of the future. Navigant Research believes that focusing on incremental improvements to advanced batteries will be the best path forward in the near term. Doing so presents a logical roadmap that allows companies and research agencies to achieve realistic results.

Pack Configuration Doesn’t Get Enough Attention

While much research has gone into the active components of the battery (i.e., the electrode and electrolyte materials), an important feature of the cell that is often overlooked is the pack configuration. Having an optimized cell design based on the desired use case of the battery can increase the cell’s efficiency by up to 23% that utilizes the same chemistry. As lithium has the tendency to swell during charge/discharge cycles, the enclosure must be robust enough to endure mechanical strain and maintain structural integrity. There are currently three main cell configurations:

  • Cylindrical: Components are encased tightly in a can. Often used in smaller electronic applications, but can be manufactured more quickly relative to other cells.
  • Prismatic: Electrodes are flat, and require slightly thicker walls compared to cylindrical cells to compensate for decreased mechanical stability. These cells are great to maximize space utilization.
  • Pouch: Has the most efficient packing structure of all cell designs and can achieve up to 95% space utilization. The pouch’s tendency to swell discourages use in certain applications and environments.

All three battery cell formats have strengths and weaknesses. The choice between pouch and cylindrical cells is still a matter in progress; Navigant Research expects cylindrical cells and pouch cells to be the most economically feasible with respect to energy density. This consideration is important, particularly in motive applications.

Stability Is Crucial for Continuing Battery Innovation

Advanced battery OEMs are taking competing strategies to tackle EV battery pack related issues. While Tesla has reported high power and energy density of its cylindrical NCM batteries, Korean battery giant SK Innovations is working on its enhanced NCM 811 battery cells in prismatic form. The industry standard for NCM batteries has been 622 (i.e., 60% nickel, 20% cobalt, and 20% manganese); NCM 811 cells are achieving higher densities, translating to up to 700 km on a full charge (~75% increase over NCM 622 cell stacks), but they fall short in terms of thermal stability and safety. SK Innovation plans to integrate its NCM 811 battery in the Kia Niro EV by 2020; it is advertised to have approximately 500 km of range and battery of over 70 kWh.

Other Battery Development Goals

LG Chem is working to deliver a cylindrical NCM 811 battery before SK Innovation, saying that it will have these cells deployed in electric buses in 2018. The company upgraded the Renault Zoe’s battery capacity up 76% while maintaining the same volume and slightly increasing the weight of the pack.

Panasonic also made improvements to its prismatic cells through construction changes. The 2019 Ford Fusion Energi PHEV received a 18% boost in energy capacity from 7.6 to 9.0 kWh. The pack is the same size with the same number of cells and unchanged chemistry, but the separator thickness inside the cell has been reduced. This allows more electrode layers inside each can, and consequently more capacity.

Remember the Big Picture

As companies continue to execute on their technology roadmaps, Navigant Research urges them to look not only at the battery chemistry, but the implications of the cell and pack design on the performance of the system. Doing so will reduce costs, help achieve higher power and energy, and allow for faster innovation across all technology product offerings.


Flow Batteries Under Fire: What’s Happening?

— April 5, 2018

There has been an uptick in news surrounding flow batteries over the past year. On the positive front, ESS, Inc. recently raised $13 million in funding from investors and announced that it will deliver two of its systems to chemical manufacturer BASF. On the negative front, Vizn Energy scaled back its business, citing the loss of one its leading investors.

Navigant Research expects flow batteries to be a major competitor to lithium ion (Li-ion) for both front-of-the-meter and behind-the-meter applications in the next several years. In fact, Navigant Research expects them to be the fastest growing electrochemical energy storage device over the next 10 years. However, short-term hurdles still exist. In this blog, I’m discussing some of the major issues.

Cost and Use Case

CAPEX of flow battery systems compared to Li-ion batteries is higher. The cost over the lifetime of the storage asset is heavily dependent on the type of applications the device will serve. We see flow batteries being utilized for long duration energy applications (over 4 hours) as opposed to short duration power applications (less than 4 hours). As their discharge duration is directly correlated with the amount of electrolytes stored in the tank, the levelized cost of energy decreases as the discharge duration increases. At present, we generally see advanced energy storage being deployed for use cases less than 4 hours. Consequently, Li-ion batteries can provide the same services that flow can at a lower CAPEX.

Component and material costs are also an issue. Current commercial flow battery chemistries are limited to vanadium-based and zinc-based chemistries. Their redox pairs yield competitive but lower power densities compared to Li-ion. Exploring different chemistries that yield higher power density and are safer, engineering better separator and electrode materials and architectures to improve chemical conversion, and decreasing other balance-of-system costs are key to improving the competitiveness of flow batteries in the current energy storage market.

Project Timelines

From signing letters of intent to the ribbon cutting of the system, Li-ion batteries are deployed on increasingly shorter timelines relative to other advanced battery technologies. This is because they have been studied more by both the public and private sectors and are well understood. Flow battery systems can be a bit bulkier and require special permitting by players across the value chain. Most customers are not as educated on flow systems compared to Li-ion or lead-acid batteries. Consequently, it is difficult to convince flow battery customers (utilities and C&I customers, mostly) to invest when they can purchase a Li-ion system at a lower CAPEX and have the system up and running faster.

Economies of Scale

Most commercial flow battery vendors outsource component manufacturing to other companies and assemble the final product in house. The demand for flow batteries has not yet boomed, and companies have not found a need to scale up production. As medium- to long-duration markets begin to open for flow batteries as they did for other types, manufacturing synergies will be developed and consequently drive the price down.

How Do Companies Plan for Success?

Going forward, it is increasingly important that flow battery companies continue to educate customers on the benefits of deploying these systems while continuing to improve on the issues outlined above. Being able to back up the 20-year warranty that most commercial flow battery vendors offer will be contingent on these improvements. Because of this, we see the players best positioned to deploy these systems in the short term as large companies that have other business units and resources to support their flow battery business. This way, if business slows or fails, the company will not be set back significantly.


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