John Doyle successfully obtained his patent for a new device in February 1880. In broad terms, this meant the granting authority agreed the Doyle flow battery was a useful new invention. Furthermore, it was also not an obvious innovation. We wrap up this short series by exploring the factors that made his idea unique.
The Doyle Flow Battery Was a Useful Invention
John Doyle was thinking ahead, when he adopted his multiple porous-jar design. That’s because each of his jars contained its own negative plate, yielding the following advantages.
- Their negatives connected to the same positive zinc plate. This yielded a ‘greatly increased current’ without accelerating the ‘rate of decomposition’ of the latter.
- This arrangement of two jars, and one zinc plate doubled the flow battery capacity, when Doyle compared it with using two jars and two zinc plates.
- Finally, the Doyle flow battery used 50% less space than a two-cell version. And saved the cost of one container, and one zinc plate too.
The Invention Comprised Several Innovations
- The porous cups grouped together, with individual negative elements combined in a single circuit. A collection funnel and drainage pipes provided a way to manage the ‘excitant’ liquid.
- A separate galvanic battery powered a way to provide fresh excitant liquid at regular intervals. An interchangeable cam admitted air to the storage chamber, in turn releasing liquid.
- This time-based system, combined with multiple porous cups, collection funnel, and excitant drain was a new and innovative arrangement. The U.S. patent authority agreed, and allowed the patent.
The Doyle Innovation Went Dormant After That
John Doyle’s zinc-bromine invention did not take off commercially, although others dabbled with his idea. The impetus of the lead acid battery probably rolled it over. Perhaps the flow battery concept was too complex, compared to the simplicity of the lead acid design.
More Information
First Flow Battery By John Doyle
