# Liquid Robotics, Inc. — Hazardous Materials Safety Interpretation - **operation:** document - **citation:** 10-0264 - **title:** Liquid Robotics, Inc. — Hazardous Materials Safety Interpretation - **source type:** guidance - **agency:** Pipeline and Hazardous Materials Safety Administration - **status:** guidance - **official:** true - **published on:** 2011-02-18 - **effective on:** Not available - **summary:** 10-0264 response to Liquid Robotics, Inc. concerning 173.185. - **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-10-0264.json - **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-10-0264.md - **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-10-0264 - **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretations/2010/100264.pdf **body:** <<>> U.S. Department of Transportation 1200 New Jersey Ave, SE Washington, D.C. 20590 Pipeline and Hazardous Materials Safety Administration / FEB j 8 2011 Mr. Roger Hine President and CEO Liquid Robotics, Inc. 1329 Moffett Park Drive Sunnyvale, CA 94089 Ref. No.: 10-0264 Dear Mr. Hine: This responds to your December 22, 2010 letter requesting clarification of the requirements in the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to lithium ion battery powered devices. Specifically, you ask us to confirm your understanding that the battery packs described in your letter are considered separate lithium ion batteries and meet all ofthe applicable requirements of § 172.1 02( c), Special Provision 188. In addition to your letter, you enclose a drawing showing the configuration of the lithium ion battery packs. According to your letter, the device contains seven 95 Wh lithium ion batteries consisting oftwelve 2.2 ampre hour cells in a 4S3P configuration. Your letter states that each of the lithium ion cells and the battery pack both meet the applicable tests outlined in the UN Manual of Tests and Criteria. The seven lithium ion battery packs are mounted in an aluminum housing that is securely attached to a drybox designed to both mechanically isolate and prevent any movement of the batteries during transport or operation. Your letter further states that each of the battery packs are electrically isolated from each other through a set of solid state switches that can only be activated through the use ofan external plug inserted into its mating jack on the drybox. The drybox will be shipped without the plug inserted and the plug secured in a manner to prevent accidental activation. Additionally, a distinct warning label affixed on the box instructs users not to transport the device with the plug inserted into the jack. Based on the information described in your letter, it is the opinion ofthis office that when the plug is removed from the mating jack, the battery packs described in your letter are electrically isolated from <<>> each other and would constitute separate lithium ion battery packs. Further, the steps taken to prevent damage, short circuits and accidental activation during transport appear to meet the requirements of § 172.102, Special Provision 188. I hope this answers your inquiry. If you need additional assistance, please contact the Standards and Rulemaking Division. SiB~5~· Ben Supko Acting Chief, Standards Development Branch Standards and Rulemaking Division <<>> 1329 Moffett Po.·k Drive Sunnyvale, CA 94089 Ph# 650-493-6300 Fax: 408-747-1923 www.liguidr.com December 22,2010 Kevin Leary Office of Hazardous Material Standards Pipeline and Hazardous Materials Safety Administration U.S. Department ofTransportation 1200 New Jersey Avenue. SE Washington, DC 20590 Re: Wave Glider Lithium Ion Battery Design Dear Mr. Leary: I am writing as a follow-up to our conference call on December 16, 2010 regarding the lithium ion battery configuration that Liquid Robotics has designed to power our product known as the Wave Glidel'TM. We would like confIrmation fmm PHMSA that our CUlTent understanding of the battery configuration meets the requirements for the small battery exception in 49 CFR § 171.102, Special Provision 188 of the U.S. Hazardous Materials Regulations (HMR) and thus is exempt from the requirements ofthe HMR. Our current understanding is based primarily on the battery defInitions in the UN Manual ofTests and Criteria, the regulatory requirements for lithium ion batteries found at 49 CFR § 173.185 and the information in the following DOT interpretation letters: Ref. #s 06-0015, 09-0066, 09-0182, 08-0029, and 10-0135. Wave Glider The Wave Glider is a madtime autonomolls surface vehicle that serves as a platform for scientific instrumentation as well as national security applications. The lithium ion batteries for the Wave Glider are designed to power the navigation control system and are enclosed in a watertight, hermetically sealed Delrin and aluminum drybox enclosure. Typical Wave Glider deployments may operate thousands ofmiles from land and last up to a year. It will be important to ship these individual batteries contained within the drybox so end-users do not need to open the drybox to install the batteries, and subsequently reseal the drybox. An impmperly performed resealing procedure would lead to failure of the navigation control system due to seawater damage and potentially result in the loss ofthe system. The Wave Glider could be used in a <<>> variety ofnational secudty and intelligence applications where resealing the drybox in the field after shipment or losing the system would be unacceptable. Lithium ion Batteries Designed for Wave Glider Liquid Robotics uses seven 95 Wh lithium ion batteries (manufactured by Inspired Energy model # NL2044) that consist of twelve 2.2 ampere-hour cells in a 4S3P configuration. Each ceU has an equivalent lithium content O.66g, and each battery has an aggregate equivalent lithium content of7.92g. The lithium ion cells and batteries have been certified in accordance with the requirements of the UN Manual ofTests and Criteria. The batteries are installed in a rugged aluminum housing that is securely attached to the drybox to both mechanically isolate the batteries and to prevent any movement of the batteries in shipping or in operation. A diagram illustrating the Wave Glider battery system is enclosed with this letter. The batteries are independently connected to the Wave Glider circuit board in order to prevent any individual battery from discharging and charging another individual battery. The batteries are electrically isolated from the rest of the system through a set ofsolid-state switches. The switches can only be activated when an external mechanical plug is inserted into its mating jack on the drybox. The system is always shipped without the plug insel1ed into the jack (and hence deactivated) to prevent any accidental charge or discharge ofany individual battery that could result in the creation of sparks or the generation of a dangerous evolution ofheat. Both the clear instructions in the Wave Glider user manual and a distinct warning label affixed on the drybox by the jack instruct users to never ship the Wave Glider with the plug inserted into the jack and the system activated. Furthelmore, during shipment, the plug is packed and secured in a manner to prevent any possibility ofaccidental insertion into the jack and unintentional activation ofthe system. In addition, the "Charge Control" and "Battery Power Combiner" circuits (shown in the diagram) ensure that each battery in the system is charged and discharged individually. To illustrate this point, the system will charge and discharge the batteries safely and properly even if batteries of different voltages, capacities, andlor chemistries are used in the same dl'ybox enclosure. There are no extemal connections to the battery circuits once the drybox is assembled to prevent any possibility ofextemaI shOl1ing. The drybox also is backfilled with dry nitrogen gas to further prevent any combustion within the drybox. * * * In swnmary, we understand our battery design consists ofseven individual batteries that meet the requirements of the small battery exception found in 49 CFR § 171. t02, Special Provision 188 of the U.S. HMR, and, when these batteties are installed in the Wave Glider and offered for transport, the Wave Glider also qualifies for the exceptions found in Special Provisio~ 188 (provided the Wave Glider plug is not connected into the jack on the dry box containing the batteries). We would appreciate written confilmation fi'om PHMSA that our understanding of these lithium ion battery regulatory requirements is consistent with previous interpretation letters issued by PHMSA on this issue. 2 <<>> Thank you very much for taking the time to discuss this matter with us on the phone and for responding to our letter. Please feel free to contact our V.P. of Legal and Legislative Affairs, Suneil Thomas, at (415) 608-1608 or suneil.thomas@liguidr.comwith any questions. Roger Hine President and CEO Liquid Robotics, Inc. 3 <<>> Wave Glider Battery System Diagram r Drybox enclosure / " Solid State Switches Inspired Energy UN compliant 95W·hr Batteries I I 1- 1-1 I 1 I I I Inspired Energy UN compliant 9SW·hr Batteries I~.J I-I~ • • • I I , • • • • Inspired Energy UN compliant 9SW·hr Batteries I • J I-I-J I I I I "Charge Circuit I-I-Control Breakers ... Cl1 c: .:0 Charge Circuit I----­ 0 E i.-Control Breakers u .... Cl1 ~ • 0 c.. >. • .... ,$ • - • IX) • III • Charge Circuit I--­ I--Control Breakers System Control Electronics ../ 1-7 batteries may be plugged into the system I I I I I I Plug is inserted into jack to activate Solid J:m:mo State Switches c=::> External Power Control ... 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