The Road to Validation – PBES Thermal Runaway Prevention Testing
By Aubrey van der Hoven, Senior Manager: Compliance and Quality Assurance, PBES
Globally, the marine industry has begun the migration to lithium-ion battery technology as an economical and environmentally acceptable alternative to fossil fuel propulsion. PBES is at the heart of this transition with its leading-edge technology [CellCool™, Thermal-Stop™, E-Vent™, etc.].
However, PBES technology would have had no role in this, unless it had been validated by the regulators of the industry, which include the United Nations, the International Maritime Organization [IMO] or authorized administrations, government agencies [Norwegian Maritime Authority (NMA), Danish Maritime Authority (DMA), etc.], and the classification societies [DNVGL, Lloyd’s Register (LR), etc.].
Witnessed testing started November 2015, and was completed in August 2017.
Propagation / Internal Thermal Event Testing
For a moment, turn back time to October 1st, 2015. The PBES test team was huddled together in a closed container on a remote corner of a foothill of mount Crickmer, a specialized fire test site outside Vancouver, British Columbia.
Fifty metres away from the container, on the other side of a 9-foot concrete wall, the PBES battery was being overcharged. No one could go outside the container.
The worst was expected and prepared for – an internal short, rapid release of gas, and an explosion that would send shrapnel flying in all directions…
The test site was evacuated, up to 420 metres away.
The internal short happened, but there was no rapid release of gas, no thermal runaway, and no explosion. Hazardous gas released was too little to be detected by the flow meter or pressure transducers. Several subsequent tests produced the same result. It became clear that the thermal runaway prevention measures were very effective.
The next step was to capture the hazardous gas in bags to measure its volume. Tests were moved indoors. The quantity of hazardous gas released was still too low for the bag sizes.
There was only one measure left, and that is to fill a beaker with water, and allow any hazardous gas released to displace the water. Finally, we managed to capture less than a liter of hazardous gas released over less than 30 seconds.
For DNVGL and NMA witnessed tests, we overcharged two batteries and three batteries respectively.
The results were so uneventful, that NMA requested PBES to showcase 3 more tests of what would happen to a single cell that is not protected by our technology. All three tests without our technology resulted in a dramatic thermal runaway event and fire.
PBES currently has 11.3 MWh class certified installations [DNVGL, LR] on 11 vessels, certified by the relevant maritime authorities [NMA, DMA], of which Tycho Brahe [4.16 MW] is the largest hybrid electric ferry in the world. Our ESS is DNVGL Type Approved, and is manufactured in an ISO 9001:2015 certified facility.