Electrochemical power generating system

• US 5,439,758 A
• Filed: 06/23/1993
• Issued: 08/08/1995
• Est. Priority Date: 10/02/1992
• Status: Expired due to Fees

• Current Assignee: Voltek Incorporated
• Original Assignee: Voltek Incorporated
• Inventors: Amick, Douglas J., McGee, Richard L., Stone, Gordon R.
• Primary Examiner(s): Richter, Johann
• Assistant Examiner(s): Hydorn, Michael B.
• Application Number:
  US08/081,662
• Time in Patent Office: 776 Days
• Field of Search: 429/22, 429/26, 429/63, 429/64, 429/70, 429/23, 429/24, 429/25, 429/27, 429/28
• US Class Current: 429/63
• CPC Class Codes: H01M 10/52 Removing gases inside the secondary cell, e.g. by absorption vent plugs or other mechanical arrangements for facilitating escape of gases H01M50/30
• CPC Class Codes: H01M 12/06 with one metallic and one gaseous electrode
• CPC Class Codes: H01M 12/065 with plate-like electrodes or stacks of plate-like electrodes
• CPC Class Codes: H01M 16/00 Structural combinations of different types of electrochemical generators
• CPC Class Codes: H01M 4/12 of consumable metal or alloy electrodes use of alloy compositions as active materials H01M4/38
• CPC Class Codes: H01M 50/77 with external circulating path
• CPC Class Codes: H01M 6/50 Methods or arrangements for servicing or maintenance, e.g. for maintaining operating temperature constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

An electrochemical power generating system has a base unit and a replaceable fuel unit. The base unit comprises controller for controlling operation of the pump. The fuel unit comprises a second housing releasably connectable to the first housing and a row of metal-air cells in the second housing electrically inter-connected together. Each cell includes a casing, a metal anode within the casing, an air cathode, a spacer between the cathode and anode for preventing the anode from contacting the cathode, an electrolyte intake port and an electrolyte discharge port in the casing for passage of electrolyte through the casing and between the anode and cathode. The fuel unit further comprises a manifold, an electrolyte reservoir, and a fluid line. The manifold has an intake port and a plurality of discharge ports in fluid communication with the electrolyte intake ports of the cells so that electrolyte flowing through the manifold is directed through the intake ports of the cells. The electrolyte reservoir and intake port of the manifold are operatively connectable with the electrolyte pump for fluid communication therewith so that the pump is able to pump electrolyte from the reservoir to the manifold. The fluid line operatively connects the discharge ports of the cells with the reservoir so that electrolyte discharged from the cells flows to the reservoir. The replaceable fuel unit is releasably attachable to the base unit so that the fuel unit can be quickly attached to and detached from the base unit.

Claims

1. An electrochemical power generating system having a base unit and a replaceable fuel unit, said base unit comprising a first housing, an electrolyte pump in the first housing, and a controller for controlling operation of the pump, said fuel unit comprising:

a second housing releasably connectable to the first housing;

a row of metal-air cells in the second housing electrically inter-connected together, each cell including a casing, a metal anode within the casing and having a reaction face, an air cathode having an outer face and an inner face with the inner face opposing the reaction face, a spacer between the inner face of the cathode and the reaction face of the anode for preventing the anode from contacting the cathode, an electrolyte intake port and an electrolyte discharge port in the casing for passage of electrolyte through the casing and between the anode and cathode;

a manifold having an intake port and a plurality of discharge ports in fluid communication with the electrolyte intake ports of the cells so that electrolyte flowing through the manifold is directed through the intake ports of the cells;

an electrolyte reservoir, said electrolyte reservoir and intake port of the manifold being operatively connectable with the electrolyte pump for fluid communication therewith so that the pump is able to pump electrolyte from the reservoir to the manifold; and

at least one fluid line for operatively connecting the discharge ports of the cells with the reservoir so that electrolyte discharged from the cells flows to the reservoir;

said replaceable fuel unit being releasably attachable to the base unit so that the fuel unit can be quickly attached to and detached from the base unit.

2. An electrochemical power generating system as set forth in claim 1 wherein the casing of each cell comprises a flexible, collapsible pouch and wherein the cells are arranged in face-to-face relationship, said power generating system further comprising means for urging opposite ends of the row of cells toward each other so that the distance between the inner face of the cathode and the reaction face of the anode of each cell remains generally constant during consumption of the anode.

3. An electrochemical power generating system as set forth in claim 2 wherein the means for urging opposite ends of the row of cells toward each other comprises a resilient harness extending around the row of cells.

4. An electrochemical power generating system as set forth in claim 3 further comprising a plurality of flexible conduits for directing electrolyte flowing through the manifold to the intake ports of the cells, each conduit having a first end connected to one of the discharge ports of the manifold and a second end connected to one of the intake ports of the cells.

5. An electrochemical power generating system as set forth in claim 1 wherein the anode of each cell comprises a generally flat plate having a first face, a second face, and a raised dendritic pattern protruding from the second face for providing structural integrity and electrical conduction across the plate, the first face of each anode comprising the first reaction face of such anode.

6. An electrochemical power generating system as set forth in claim 1 further comprising a depolarization air system for feeding air to the cathode of each cell.

7. An electrochemical power generating system as set forth in claim 1 wherein the controller is in the first housing.

8. An electrochemical power generating system as set forth in claim 1 wherein the manifold and electrolyte reservoir are at least partially contained by the second housing.

9. An electrochemical power generating system as set forth in claim 1 further comprising first and second fluid conduits operatively connected to the pump, and quick-release fluid line connectors for operatively connecting the reservoir and intake manifolds to the first and second fluid conduits, said quick-release fluid line connectors facilitating quick attachment and detachment between the fuel unit and base unit.

10. An electrochemical power generating system comprising:

at least one metal-air cell;

an electrolyte reservoir;

electrolyte transport means including a pump for pumping electrolyte from the reservoir and moving it through the cell;

a sensor for sensing an operating condition of the generating system; and

a controller responsive to the sensor for selectively energizing the pump as a function of the sensed operating condition whereby energizing the pump causes electrolyte to be transported from the reservoir to the cell.

11. An electrochemical power generating system as set forth in claim 10 wherein the sensor is a temperature sensor for sensing the temperature of electrolyte in the system.

12. An electrochemical power generating system as set forth in claim 11 wherein the controller energizes the pump when sensed electrolyte temperature exceeds a temperature T₁.

13. An electrochemical power generating system as set forth in claim 12 wherein the controller is responsive to the temperature sensor for energizing the pump for a brief duration D₁ to pump a charge of electrolyte into the cell where the charge is held substantially statically in the cell until the sensed electrolyte temperature exceeds the temperature T₁, whereupon the pump is again energized by the controller for a duration D₁ to pump another charge of electrolyte into the cell.

14. An electrochemical power generating system as set forth in claim 10 wherein the controller is adapted for energizing the pump for a duration D₁.

15. An electrochemical power generating system as set forth in claim 14 wherein the duration D₁ is a function of the sensed operating condition.

16. An electrochemical power generating system as set forth in claim 10 further comprising means for cooling electrolyte, said controller being adapted for selectively energizing the electrolyte cooling means as a function of the sensed operating condition whereby energizing the electrolyte cooling means cools the electrolyte.

17. An electrochemical power generating system as set forth in claim 16 wherein the controller is adapted for energizing the electrolyte cooling means when electrolyte in the power generating system exceeds a temperature T₃, and for deenergizing the electrolyte cooling means when the temperature of the electrolyte is less than a temperature T₂.

18. An electrochemical power generating system as set forth in claim 10 wherein the pump comprises a reversible pump.

19. An electrochemical power generating system as set forth in claim 10 wherein the electrolyte transport means further comprises at least one conduit for conveying electrolyte from the pump to the cell.

20. An electrochemical power generating system as set forth in claim 19 further comprising first conveying means for conveying electrolyte from the cell to one of the electrolyte transport means and the electrolyte reservoir.

21. An electrochemical power generating system as set forth in claim 20 wherein said first conveying means further comprises a sump for collecting reaction products discharged from the cells.

22. An electrochemical power generating system as set forth in claim 21 further comprising a catalytic converter for catalyzing the conversion to water of hydrogen produced by the cell.

23. An electrochemical power generating system as set forth in claim 22 further comprising second conveying means for conveying water from the catalytic converter to the first conveying means.

24. An electrochemical power generating system as set forth in claim 10 wherein said sensor comprises a first temperature sensor for sensing the temperature of electrolyte in the system, said power generating system further comprising a second temperature sensor for sensing the temperature of electrolyte in the cell, the controller being responsive to said first and second temperature sensors and capable of:

(a) turning the pump on for a first duration t₁ and turning the pump off for a second time period t₂ ;

(b) repeating (a) until the second temperature sensor senses an electrolyte temperature of at least T₁.

25. An electrochemical power generating system as set forth in claim 24 wherein the controller is further capable of repeating (a) and (b) until the first temperature sensor senses an electrolyte temperature of at least T_S and then turning the pump on to run continuously.

26. An electrochemical power generating system as set forth in claim 10 wherein said sensor comprises a first temperature sensor for sensing the temperature of electrolyte in the electrolyte transport means, said power generating system further comprising a second temperature sensor for sensing the temperature of electrolyte in the cell, the controller being responsive to the first and second temperature sensors for (a) energizing the pump for a brief duration D₁ when the first temperature sensor senses an electrolyte temperature less than a temperature T_S to pump a charge of electrolyte into the cell where the charge is held substantially statically in the cell until the second temperature sensor senses an electrolyte temperature in excess of the temperature T₁ and (b) energizing the pump continuously when the first temperature sensor senses an electrolyte temperature in excess of the temperature T_S.

27. An electrochemical power generating system comprising:

a battery having at least one metal-air cell including a casing, a metal anode within the casing and having a reaction face, and an air cathode having an outer face and an inner face with the inner face opposing the reaction face; and

a controller for causing a bias voltage to be applied to the battery during periods when the battery is not supplying current to a load thereby to inhibit anode depletion, and for causing removal of the bias voltage from the battery after the bias voltage has been applied to the battery for a duration D₂ ;

said bias voltage being of like polarity and of a potential at least equal to that of the battery.

28. An electrochemical power generating system as set forth in claim 27 wherein the source of the bias voltage is a secondary battery.

29. An electrochemical power generating system for supplying power to an electrical load comprising:

a primary battery having at least one metal-air cell including a casing, an anode within the casing and having a reaction face, an air cathode having an outer face and an inner face with the inner face opposing the reaction face, an electrolyte intake port in the casing for passage of electrolyte through the casing and between the anode and cathode, and an electrolyte discharge port in the casing; and

means for heating electrolyte within the battery when the temperature of the electrolyte is below a minimum temperature.

30. An electrochemical power generating system as set forth in claim 29 wherein said heating means comprises a supplemental power source connected in series with the primary battery for selectively carrying the load whereby current from the supplemental power source passes through the primary battery to heat the electrolyte.

31. An electrochemical power generating system as set forth in claim 30 further comprising a controller for operatively connecting the primary battery and supplemental power source in series when the temperature of the electrolyte is below the minimum temperature and for operatively connecting the battery and supplemental power source in parallel when the temperature is above the minimum temperature.

32. An electrochemical power generating system as set forth in claim 31 further comprising a sensor for sensing electrolyte temperature within the primary battery, said controller being responsive to the sensor.

33. An electrochemical power generating system as set forth in claim 32 wherein the supplemental power source comprises a secondary battery.

34. An electrochemical power generating system comprising:

a battery having at least one metal-air cell including a casing, a metal anode within the casing and having a reaction face, an air cathode having an outer face and an inner face with the inner face opposing the reaction face, an electrolyte intake port and an electrolyte discharge port in the casing for passage of electrolyte through the casing and between the anode and cathode; and

a controller for causing a bias voltage to be applied to the battery during periods when the battery is not supplying current to a load thereby to inhibit anode depletion, and for causing emptying of electrolyte from the casing of the cell after the bias voltage has been applied to the battery for a duration D₂ ;

said bias voltage being of like polarity and of a potential at least equal to that of the battery.