Chemistry: electrical current producing apparatus – product – and – With pressure equalizing means for liquid immersion operation
Patent
1996-06-27
1998-08-04
Kalafut, Stephen
Chemistry: electrical current producing apparatus, product, and
With pressure equalizing means for liquid immersion operation
429 62, H01M 1050
Patent
active
057890927
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention concerns a method for prevention of cooling of electrochemical devices.
The invention also concerns an equipment for prevention of cooling of electrochemical devices.
BACKGROUND OF THE INVENTION
Cold climatic conditions cause danger of freezing to electrochemical devices, such as, for example, fuel cells. As is well known, it is possible to use fuel cells connected to a hydrogen storage to produce electric energy in sparsely inhabited regions. Normally, as the fuel cell is in operation, the waste heat which develops in the fuel cells is enough to keep the fuel cell sufficiently warm. However, if the loading is too low to keep the fuel cell sufficiently warm or the fuel cell is not in operation and, thus, is not connected to loading, freezing of the fuel cell can take place. Malfunction in the system may also cause freezing of the fuel cell.
The most problematic freezing takes place in fuel cells of the solid-polymer electrolyte type. An excessively low temperature may also cause difficulties or at least slowness in the starting in other kinds of fuel cells such as, for example, alkali-type, phosphoric-acid type, etc. In solid-polymer type fuel cells the key component is a membrane which conducts protons, which membrane contains mainly water. If the water in the membrane freezes, it prevents the conducting of the protons in the membrane, and the fuel cell cannot operate. Freezing can also permanently damage the structure of the fuel cell by causing mechanical strain on the cell.
Solidification or weakening of the operation at temperatures lower than a normal temperature are also a problem in fuel cells which operate at higher temperatures.
As regards the prior art, reference is made to the publication JP-59-214166, in which publication an outside electric heater is suggested which heats nitrogen gas. By means of this, freezing of phosphoric acid is prevented in phosphoric-acid type fuel cells.
OBJECTS AND SUMMARY OF THE INVENTION
The object of the invention is to provide an improvement over the prior-art solutions. A more specific object of the invention is to provide a method and an equipment by means of which it is possible to reliably prevent harmful cooling of electrochemical devices.
The method in accordance with the invention is characterized in that the temperature of the electrochemical device is measured and, as the temperature falls below a certain pre-set lower limit, an additional load is connected to the device (in parallel with the existing load) which additional load is at least high enough to cause an electric current which heats the electrochemical device, and that said additional load is disconnected from the electrochemical device as the temperature has reached a certain pre-chosen upper limit.
The equipment in accordance with the invention is characterized in that the equipment includes a control member, which measures the temperature and carries out the switching-on at a certain low temperature of the load into the circuit and the switching-off at a certain high temperature, and a member which loads the electrochemical device, which loading member is, by the effect of said control member, switched on at a certain low temperature and causes an increase in electric current which flows through the electrochemical device and heats it, and which loading member is, by the effect of said control member, disconnected at said high temperature to switch off the electric current which heats the electrochemical device.
In the solution in accordance with the invention, the temperature of the electrochemical device, for example a fuel cell, is measured, and as the temperature falls below a certain pre-chosen lower limit T.sub.minimum, the additional loading is connected in parallel with the existing load, e.g., the internal resistance of the fuel cell. As the additional loading is connected, the electric current starts to circulate through the circuit which consists of the additional loading and of the inner resistance in the fuel cell. The electric current
REFERENCES:
patent: 2516048 (1950-07-01), Endress
patent: 3512071 (1970-05-01), Daniels
patent: 5200278 (1993-04-01), Watkins et al.
patent: 5302471 (1994-04-01), Ito et al.
Patent Abstracts of Japan, vol. 12, No. 328 (E-624), Abstract of Published Japanese Patent Application No. 63-91967. Apr. 1988.
Patent Abstracts of Japan, vol. 10, No. 16 (E-375), Abstract of Published Japanese Patent Application No. 60-177568. Sep. 1985.
Patent Abstracts of Japan, vol. 9, No. 81(E-307), Abstract of Published Japanese Patent Application No. 59-214166. Dec. 1984.
Leppanen Jyrki Rainer
Spiers David John
Kalafut Stephen
Neste Oy
LandOfFree
Method and equipment for prevention of cooling of electrochemica does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and equipment for prevention of cooling of electrochemica, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and equipment for prevention of cooling of electrochemica will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1175144