Patent ID: 8349477

Claim:
A method of detecting a fluid leak in a redox flow cell battery system, the redox flow cell battery system comprising a pair of electrodes disposed in separate half-cell compartments; a porous or ion-selective membrane separating the half-cell compartments; and an electrolyte that is flowed through the half-cell compartments, wherein the electrolyte is stored in one or more electrolyte storage containers, a leak detector is positioned external to one or more of the electrolyte storage containers, wherein the leak detector comprises: a device housing, the device housing comprising bottom surfaces; at least one light source in the device housing; and at least one light detector in the device housing; and the method comprising: emitting a light from the light detector, wherein the emitted light is at least partially reflected from the bottom surfaces of the device housing, and is at least partially refracted by the bottom surfaces and fluid in contact with at least a portion of the bottom surface that the light is incident upon; detecting at least a portion of the at least partially reflected and partially refracted light using at least one of the light detectors; determining the composition of fluid in contact with at least a portion of the bottom surfaces of the leak detector based on the difference between the measured light intensity and the intensity of light produced by the light source.