Zinc bromine battery

In the comparison of battery types (search the wiki) it became apparent that Zinc bromine may in fact be a very promising option for OSE puroses:

- it is an old technology, more than 30 years old.

- it is more efficient than nife. 75% for existing batteries but this might be increases to 80 by designing for efficiency, 82% theoretical max i.e. using ion exchange rather than porous separator membranes, using single, non-flow cells that do not share electrolyte. Big impact on cost.

Extremely cheap: in 2 places have seen in quoted that production cost including labor etc to the mfgr can be about $28/kWh.

common materials: zinc pretty common and bromine commercially extracted from seawater. Plastics seen in docs are not exotic, polyethylene etc. Carbon electrodes sound very easy to make.

Easier to produce : no packing of active materials into the electrodes of need to worry about particle sizes etc, just solutions. No flits. No electroplating.

- reasonable density, 3 to 4 times that of lead acid

- easy to rebuild

- low toxicity materials and components, zinc very low toxicity and bromine not bad though don't want to breath it.

Issues remaining that shoudl be clarified:

Vapor pressure above the bromine solution: if higher than atmospheric a bit of a safety prob

Sealing? how much gas is evolved and is the chemistry amenable to recombination without a noble metal catalyts? Usually in flow batteries when it is fully charged the electrolyte doesn't have much in it any more and so is not very conductive, preventing overcharge and associated water electrolysis. There seems to get very little mention, but there is some in the doc from ottawa U that mentions quite small amounts are evolved. need to check again how much 1.8 ml per cycle but for what size capacity.

lifetime limiting issues. A number of pages indicate that there are a couple potential issues but the commercial batteries appear to have resolved them, achieving 20 year lifetimes www.zbb.com, we need acess to journals again to work them out in reasonable detail (this is clearly going to be a problem on not just this but many projects, something should be done to secure access, a library access team like the CAD team would be good):

attack of the plastics by the bromine, solved by finding good plastics compatible

loss of activity of the bromine electrode somehow - elsewhere is mentioned adding ammonium functional groups to it (attached by adsorption presumably) to catalyze the reaction.

instability of the electrolyte

Instabiilty of the membrane. Stable membranes have apparently been found. They can just be microporous for 80% eff in passive batt according to ottawa U doc, fill the pores with ion permeable material is an option and also using ion exchange membranes, thick enough.

searched for info on non-flow batteries and found only the following:

Pritam Singh, Bjorn Jonshagen, Zinc---bromine battery for energy storage, Journal of Power Sources, Volume 35, Issue 4, September 1991, Pages 405-410, ISSN 0378-7753, DOI: 10.1016/0378-7753(91)80059-7. (http://www.sciencedirect.com/science/article/pii/0378775391800597)

David Ayme-Perrot, Serge Walter, Zelimir Gabelica, Sabine Valange, Evaluation of carbon cryogels used as cathodes for non-flowing zinc-bromine storage cells, Journal of Power Sources, Volume 175, Issue 1, 3 January 2008, Pages 644-650, ISSN 0378-7753, DOI: 10.1016/j.jpowsour.2007.09.076. (http://www.sciencedirect.com/science/article/pii/S0378775307020046) Keywords: Zinc-bromine cell; Megaloporous carbon cryogels; Energy storage

Modeling of Zinc Bromide Energy Storage for Vehicular Applications Manla, E.; Nasiri, A.; Rentel, C.H.; Hughes, M.; Univ. of Wisconsin, Milwaukee, WI, USA

This paper appears in: Industrial Electronics, IEEE Transactions on Issue Date: Feb. 2010 Volume: 57 Issue:2 On page(s): 624 - 632 ISSN: 0278-0046 References Cited: 12 Cited by : 3 INSPEC Accession Number: 11054644 Digital Object Identifier: 10.1109/TIE.2009.2030765 Date of Publication: 28 August 2009 Date of Current Version: 12 January 2010 Sponsored by: IEEE Industrial Electronics Society Abstract

Energy storage devices such as lithium-ion and nickel-metal hydrate batteries and ultracapacitors have been considered for utilization in plug-in hybrid electric vehicles (HEVs) and HEVs to improve efficiency and performance and reduce gas mileage. In this paper, we analyze and model an advanced energy storage device, namely, zinc bromide, for vehicular applications. This system has high energy and power density, high efficiency, and long life. A series of tests has been conducted on the storage to create an electrical model of the system. The modeling results show that the open-circuit voltage of the battery is a direct function of the battery's state of charge (SOC). In addition, the battery internal resistance is also a function of SOC at constant temperature. A Kalman filtering technique is also designed to adjust the estimated SOC according to battery current. googel found the mentino in the body text

Modeling of zinc energy storage system for integration with renewable energy This paper appears in: Industrial Electronics, 2009. IECON '09. 35th Annual Conference of IEEE Issue Date: 3-5 Nov. 2009 On page(s): 3987 - 3992 Location: Porto ISSN: 1553-572X E-ISBN: 978-1-4244-4650-6 Print ISBN: 978-1-4244-4648-3 References Cited: 17 INSPEC Accession Number: 11139564 Digital Object Identifier: 10.1109/IECON.2009.5415330 Date of Current Version: 17 February 2010 Abstract

Utility scale energy storage devices have been considered for integration with renewable energy systems to improve their sustainability and dispatch. In this paper, we analyze and model an advanced zinc energy storage device (ZESS), for grid level applications. This energy storage system has high energy and power density, high efficiency and long life. A series of tests have been conducted on the ZESS in order to develop an electrical model that describes its behavior. The modeling is based on the observation that, at constant temperature, both the open circuit voltage of the ZESS and its internal resistance are exclusive functions of its state of charge (SOC). Since the value of the SOC is crucial to the developed model, and due to the inexistence of charge sensors, Kalman filtering is used to estimate the SOC of the ZESS at any operating point. The model and the SOC estimator are necessary blocks to use when integrating the ZESS with some renewable energy system so that the controller can decide whether the ZESS should store/release energy from/to the system. again in the body text

also there was one PDF that was accessible http://www.ruor.uottawa.ca/fr/bitstream/handle/10393/9521/NN00593.PDF?sequence=1

and http://prod.sandia.gov/techlib/access-control.cgi/1999/992691.pdf