battery performance
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The third edition of a Battery Performance Scorecard – an independent ranking and evaluation of different types of commercial Li-ion batteries – based on testing performed in consulting firm DNV GL’s battery performance and safety test laboratories has been released.

The 2020 scorecard provides insights into the evolution of the energy storage market, and found a shift in preferred battery chemistries, as well as an influx of new system designs that will improve safety.

The battery performance study’s key findings are outlined below.

The industry is changing

Despite the impact of COVID-19, the energy storage market is growing and transforming, which demands increased investment assurance.

While lithium nickel manganese cobalt oxide (NMC) and lithium nickel cobalt aluminum oxide (NCA) chemistries remain a signature of the stationary energy storage sector, the industry is seeing a shift toward lithium iron phosphate chemistry.

In addition to cell level changes, the Scorecard’s authors noted the following industry shifts, which may impact cell original equipment manufacturers (OEMs) in the future.

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Firstly, rather than requiring human entry, energy storage systems (ESS) have moved to compartmentalised modular units that can be accessed and maintained from the outside.

Secondly, the practice of the engineering, procurement, and construction (EPC) offering a full wrap (a back-to-back alignment of their warranties and guarantees with other suppliers in the project) may be changing as well, as EPC contractors transfer risk to insurance.

While insurance company Munich Re recently announced products to back energy storage warranties, this change also highlights the need in the industry for greater asset assurance, which independent testing provides.

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Continued and growing emphasis on fire safety

The 2020 Battery Performance Scorecard notes that the industry is focusing on fire safety—and more specifically, combustion of flammable off-gases, which are generated during thermal runaway—in the post-2019 energy storage system design era.

While newer system designs can prevent the cascading of thermal runaway from unit to unit, ignition of flammable off-gas has emerged as the prime failure mode to avoid or safely manage in light of the lessons learned from the 2019 APS McMicken event and others since.

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Several issues exist with the release of the 2020 NFPA 855 safety standard and the reliance on UL9540A testing—inconsistencies in test report formats and definitions, as well as a broad definition of what constitutes an energy storage unit.

These standards will evolve with future industry input.

Building confidence in battery performance

Richard S. Barnes, region president North America at DNV GL – Energy, said: “Battery investors, EPCs, and developers need confidence that their battery choice is right for their application, the warranties are sound, performance is predictable, and systems are safe. A robust and independent testing programme is foundational to the future of the industry.

“The Battery Performance Scorecard builds confidence and helps to accelerate the market, making data about battery safety and performance more transparent and easier to verify with independent reviews.”

Read more about the Battery Performance Scorecard