Metal/Air Battery with Gas Separations Unit and Load-Leveling Oxygen Storage System

Abstract

A metal/air battery includes an oxygen management system that delivers oxygen to the battery during a discharge cycle. The oxygen management system includes an oxygen separations unit and an oxygenated gas supply reservoir that are fluidly coupled to a positive electrode of the battery via a valve system. The valve system selectively places the oxygen separations unit and the oxygenated gas supply reservoir in fluid communication with the positive electrode during the discharge cycle. The oxygen management system also includes a compressor with an outlet fluidly coupled to the oxygenated gas supply reservoir and an inlet fluidly connected to the oxygen separations unit via the valve system. The valve system selectively places the oxygen separations unit in fluid communication with the oxygenated gas supply reservoir during one or more of the discharge cycle and a charge cycle of the battery.

Claims

1. A metal/air battery with an oxygen management system, comprising: a negative electrode; a positive electrode; a separator positioned between the negative electrode and the positive electrode; an oxygen separations unit; an oxygenated gas supply reservoir; at least one valve fluidly coupled to the oxygen separations unit, the oxygenated gas supply reservoir, and the positive electrode and, during a discharge cycle, configured to: selectively place the oxygen separations unit in fluid communication with the positive electrode, and selectively place the oxygenated gas supply reservoir in fluid communication with the positive electrode.

2. The metal/air battery of claim 1, further comprising: a compressor with an outlet fluidly coupled to the oxygenated gas supply reservoir; and a second valve fluidly coupled to the oxygen separations unit and to an inlet of the compressor and configured to selectively place the oxygen separations unit in fluid communication with the oxygenated gas supply reservoir via the compressor.

3. The metal/air battery of claim 1, further comprising: a blower fluidly coupled to the oxygen separations unit and configured to increase a pressure of oxygen from the oxygen separations unit to the positive electrode.

4. The metal/air battery of claim 2, further comprising: a blower fluidly coupled to the oxygen separations unit and configured to increase a pressure of oxygen from the oxygen separations unit to the positive electrode; and a third valve fluidly coupled to the oxygen separations unit and to an inlet of the blower and configured to selectively place the oxygen separations unit in fluid communication with the blower.

5. The metal/air battery of claim 1, wherein the at least one valve includes: a first valve that selectively places the oxygen separations unit in fluid communication with the positive electrode, and a second valve that selectively places the oxygenated gas supply reservoir in fluid communication with the positive electrode.

6. The metal/air battery of claim 1, wherein: the oxygen separations unit is in fluid communication with the positive electrode when the battery discharges at a first discharge power, the oxygenated gas supply reservoir in fluid communication with the positive electrode when the battery discharges at a second discharge power, and the second discharge power is greater than the first discharge power.

7. The metal/air battery of claim 6, wherein the first discharge power corresponds to an average discharge power of the battery and the second discharge power corresponds to a peak discharge power of the battery.

8. The metal/air battery of claim 2, wherein the oxygen separations unit is in fluid communication with the oxygenated gas supply reservoir during a charge cycle of the battery.

9. The metal/air battery of claim 1, further comprising: a gas outlet valve fluidly coupled to the positive electrode and configured to selectively place the positive electrode in fluid communication with the atmosphere, wherein the positive electrode is in fluid communication with the atmosphere to vent one or more of unconsumed oxygen during the discharge cycle and accumulated oxygen during a charge cycle.

10. The metal/air battery of claim 5, further comprising: a compressor with an outlet fluidly coupled to the oxygenated gas supply reservoir; a third valve fluidly coupled to the oxygen separations unit and to an inlet of the compressor and configured to selectively place the oxygen separations unit in fluid communication with the oxygenated gas supply reservoir via the compressor; a blower fluidly coupled to the oxygen separations unit and configured to increase a pressure of oxygen from the oxygen separations unit to the positive electrode; and a fourth valve fluidly coupled to the oxygen separations unit and to an inlet of the blower and configured to selectively place the oxygen separations unit in fluid communication with the blower, wherein the first valve is fluidly coupled to an outlet of the blower and configured to place the blower in fluid communication with the positive electrode.

11. A battery management system, comprising: a metal/air battery including a negative electrode, a positive electrode, and a separator positioned between the negative electrode and the positive electrode; an oxygen management system including an oxygen separations unit, an oxygenated gas supply reservoir, and a valve system fluidly coupled to the oxygen separations unit, the oxygenated gas supply reservoir, and the positive electrode; a memory in which command instructions are stored; and a processor operably connected to the valve system and, during a discharge cycle, configured to execute the command instructions to: selectively place the oxygen separations unit in fluid communication with the positive electrode, and selectively place the oxygenated gas supply reservoir in fluid communication with the positive electrode.

12. The battery management system of claim 11, wherein: the oxygen management system further includes a compressor with an outlet fluidly coupled to the oxygenated gas supply reservoir, the valve system is fluidly coupled to an inlet of the compressor, and the processor is further configured to execute the command instructions to selectively place the oxygen separations unit in fluid communication with the oxygenated gas supply reservoir via the compressor.

13. The battery management system of claim 1, wherein the oxygen management system further includes a blower fluidly coupled to the oxygen separations unit and configured to increase a pressure of oxygen from the oxygen separations unit to the positive electrode.

14. The battery management system of claim 12, wherein: the oxygen management system further includes a blower fluidly coupled to the oxygen separations unit, the valve system is fluidly coupled to an inlet of the blower, and the processor is further configured to execute the command instructions to selectively place the oxygen separations unit in fluid communication with the blower.

15. The battery management system of claim 11, wherein the valve system includes: a first valve fluidly coupled to the oxygen separations unit and the positive electrode, and a second valve fluidly coupled to oxygenated gas supply reservoir and the positive electrode, the processor further configured to execute the command instructions to: selectively place the oxygen separations unit in fluid communication with the positive electrode via the first valve, and selectively place the oxygenated gas supply reservoir in fluid communication with the positive electrode via the second valve.

16. The battery management system of claim 1, wherein the processor is further configured to execute the command instructions to: place the oxygen separations unit in fluid communication with the positive electrode when the battery discharges at a first discharge power, and place the oxygenated gas supply reservoir in fluid communication with the positive electrode when the battery discharges at a second discharge power, the second discharge power greater than the first discharge power.

17. The battery management system of claim 16, wherein the first discharge power corresponds to an average discharge power of the battery and the second discharge power corresponds to a peak discharge power of the battery.

18. The battery management system of claim 12, wherein the processor is further configured to execute the command instructions to selectively place the oxygen separations unit in fluid communication with the oxygen gas supply reservoir during a charge cycle of the battery.

19. The battery management system of claim 11, wherein: the valve system includes a gas outlet valve fluidly coupled to the positive electrode, and the processor is further configured to execute the command instructions to selectively place the gas outlet valve in fluid communication with the atmosphere.

20. The battery management system of claim 11, wherein the processor is further configured to execute the command instructions to regulate a flow rate of oxygen from one or more of the oxygen separations unit and the oxygenated gas supply reservoir with the valve system.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0027] FIG. 1 depicts a plot showing the relationship between battery weight and vehicular range for various specific energies;

[0028] FIG. 2 depicts a chart of the specific energy and energy density of various lithium-based cells;

[0029] FIG. 3 depicts a prior art lithium/oxygen cell including two electrodes, a separator, and an electrolyte; and

[0030] FIG. 4 depicts a schematic view of a vehicle battery system including a lithium/oxygen cell with two electrodes and an oxygen management system that is configured to supply oxygen to the cell during a discharge cycle.

DESCRIPTION

[0031] For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the disclosure is thereby intended. It is further understood that the disclosure includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the disclosure as would normally occur to one of ordinary skill in the art to which this disclosure pertains.

[0032] A schematic of a vehicle battery system 300 including an electrochemical cell 100 and an oxygen management system 150 is shown in FIG. 4. The electrochemical cell 100 includes a negative electrode 102 separated from a positive electrode 104 by a porous separator 106. The negative electrode 102 may be formed from lithium metal or a lithium-insertion compound (e.g., graphite, silicon, tin, LiAl, LiMg, Li.sub.4Ti.sub.5O.sub.12), although Li metal affords the highest specific energy on a cell level compared to other possible negative electrodes. Other metals may also be used to form the negative electrode, such as Zn, Mg, Na, Fe, Al, Ca, Si, and others. In the example of FIG. 4, a current collector 107 is electrically connected to the metal in the negative electrode 102.

[0033] The positive electrode 104 in this embodiment includes a current collector 108 and electrode particles 110 that are suspended in a porous matrix 112. The electrode particles 110 are optionally covered in a catalyst material. The electrode particles 110 may be in the form of a thin, stabilizing coating to limit reaction between any discharge products and the electrode particles 110. The porous matrix 112 is an electrically conductive matrix formed from a conductive material such as conductive carbon or a nickel foam, although various alternative matrix structures and materials may be used. The separator 106 prevents the negative electrode 102 from electrically connecting with the positive electrode 104.

[0034] The electrochemical cell 100 includes an electrolyte solution 114 present in the positive electrode 104 and in some embodiments in the separator 106. In the exemplary embodiment of FIG. 4, the electrolyte solution 114 includes a salt, LiPF.sub.6 (lithium hexafluorophosphate), dissolved in an organic solvent mixture. The organic solvent mixture can be any desired solvent. In certain embodiments, the solvent can be dimethoxyethane (DME), acetonitrile (MeCN), ethylene carbonate, or diethyl carbonate. The cell 100 in some embodiments includes a barrier 116 that encloses a portion of the positive electrode 104. The barrier 116 allows oxygen to pass into the positive electrode 104 while at the same time preventing the electrolyte solution 114 from leaking out from the positive electrode 104.

[0035] The oxygen atoms and Li.sup.+ ions within the positive electrode 104 form a discharge product inside the positive electrode 104, aided by the optional catalyst material on the electrode particles 110. As seen in the following equations, during the discharge process metallic lithium is ionized, combining with oxygen and free electrons to form Li.sub.2O.sub.2 or Li.sub.2O discharge product that may coat the surfaces of the carbon particles 110.

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[0036] In the example of FIG. 4, the cell 100 is coupled to the oxygen management system 150. The oxygen management system 150 includes an oxygen separations unit 154, an oxygen supply reservoir 166, a compressor 174, and a valve system including a plurality of valves 180, 182, 184, and 186. The oxygen management system 150 can also include an optional blower 190 that is coupled between the separations unit 154 and the cell 100. The vehicle battery system 300 in the embodiment shown includes a processor 302 which is operatively connected to a memory 304. The processor 302 is operable to execute command instructions stored in the memory 304 to control various aspects of the vehicle battery system 300. As discussed in further detail below, the processor 302 can be operatively connected to various components of the vehicle battery system 300, such as one or more of the valves 180, 182, 184, and 186, to form a battery management system 306.

[0037] While the oxygen management system 150 is depicted as being coupled to the single cell 100 for illustrative purposes in FIG. 4, the oxygen management system 150 can be coupled to a plurality of cells in one or more battery packs to provide a centralized storage and control system for oxygen in a larger battery system. In an exemplary embodiment, the battery packs including the cell 100 and oxygen management system 150 are incorporated into a motor vehicle. In another non-limiting example, the cell 100 and oxygen management system 150 are electrically connected to an electrical power generator, such as a wind or solar power generator, to store energy for use when the electric power generator is not operating at full capacity.

[0038] In the configuration depicted in FIG. 4, the oxygen management system 150 handles a gas with a composition that is similar to standard air in the atmosphere, but that can be filtered to remove moisture (H.sub.2O), carbon monoxide (CO), carbon dioxide (CO.sub.2), nitrogen oxide (NO.sub.x) compounds that are commonly associated with smog, and other contaminants that can negatively impact the operation of the cell 100. In particular, contaminants that react with catalyst materials in the positive electrode 104 to “poison” the catalyst can be filtered at one or more locations in the oxygen management system 150. Also, some of the common components of air such as CO.sub.2 and H.sub.2O react with the discharge product Li.sub.2O.sub.2 to form LiOH and/or Li.sub.2CO.sub.3, which damages the cell. In another configuration, the oxygen management system 150 handles high concentrations of oxygen, which is to say that the system 150 handles pure oxygen or oxygen at a measurably higher concentration than is typically present in the atmosphere.

[0039] During a discharge cycle, the cell 100 admits oxygen to the positive electrode 104. The oxygen management system 150 is configurable in a variety of operating states to deliver oxygen to the cell 100 and enable the oxygen to flow through the barrier 116 and into the positive electrode 104. In particular, the oxygen management system 150 is configurable to: (a) supply oxygen to the cell 100 from the oxygen separations unit 154, (b) supply oxygen to the oxygen supply reservoir 166 from the oxygen separations unit 154, (c) supply oxygen to both the cell 100 and the oxygen supply reservoir 166 from the oxygen separations unit, (d) supply oxygen to the cell 100 from the oxygen supply reservoir 166, (e) supply oxygen to the cell 100 from both the oxygen separations unit 154 and the oxygen supply reservoir 166, and (f) supply oxygen to the cell 100 from both the oxygen supply reservoir 166 and the oxygen separations unit 154 and additionally supply oxygen to the oxygen supply reservoir 166 from the oxygen separations unit 154.

[0040] The oxygen separations unit 154 is sized to provide oxygen continuously during the duty cycle at a rate sufficient to maintain the average discharge power of the cell (e.g., 50 kW over a three to four hour discharge for an electric vehicle). The oxygen separations unit 154 depicted in FIG. 4 draws in standard air in the atmosphere through an inlet (depicted schematically at 155). In one embodiment, the air is passed over an oxygen conductive layer (not shown) that allows oxygen to pass through the conductive layer while other components of the air remain outside the oxygen conductive layer. The oxygen conducting layer in this embodiment includes a relatively thick membrane (>>50 nm) consisting of an oxygen conducting material. In order to allow sufficient gas transport through the membrane, a heating grid is embedded in the membrane volume of some embodiments. An example of an oxygen conducting layer that can be implemented in the oxygen separations unit 154 is described in more detail in U.S. Patent Application Publication No. 2014-0234731 A1, the disclosure of which is incorporated herein by reference in its entirety.

[0041] The oxygen supply reservoir 166 is sized to provide oxygen to the cell at higher flow rates when the cell 100 is subject to a higher discharge power (e.g., 300 kW for up to one minute for acceleration of an electric vehicle). In an illustrative example using the assumptions discussed with reference to Scenario 1 and Scenario 2 above, the oxygen supply reservoir 166 is configured to store approximately 5% of the required the oxygen and the oxygen separations unit 154 is configured to provide purified oxygen continuously during the duty cycle at a rate sufficient for 50 kW average power. Assuming linear scaling, the total mass of the oxygen supply reservoir 166 and oxygen separations unit 154 would be (2+17)=19 kg, and the total volume would be (3+24)=27 L, which are significantly less than the respective masses and volumes of either Scenario 1 or Scenario 2. Assuming advances in technology, the cost of the oxygen separations unit 154 would drop to $300, which is in an acceptable range for a 100-kWh system (˜3% of the system cost assuming $100/kWh).

[0042] It should be understood that the oxygen separations unit 154 and the oxygen supply reservoir 166 in other embodiments can be sized to accommodate different peak/average power ratios and peak-power discharge times. For instance, it may be desirable to provide enough oxygen in the oxygen supply reservoir 166 to provide for two minutes of discharge at 300 kW.

[0043] In this case, the total mass and volumes of the oxygen supply reservoir 166 and the oxygen separations unit 154 would be 21 kg and 30 L, respectively. While the oxygen management system 150 of FIG. 4 is described with reference to a vehicle battery system, it should be understood that the environment of the oxygen management system is not in any way meant to limit application of the principles of the oxygen management system to other environments. For example, as noted above, the oxygen management system could be operatively connected to an electrical power generator. As such, the oxygen management system 150 can be scaled up or down to accommodate larger or smaller peak/average power ratios and peak-power discharge times as may be expected in an electrical power generator.

[0044] In the embodiment shown in FIG. 4, the oxygen separations unit 154 is pneumatically connected to the cell 100 via conduit 192 and conduit 194. The conduit 192 forms a continuous line for flow of oxygen from the oxygen separations unit 154 to the cell 100. The oxygen supply reservoir 166 and the compressor 174 are disposed along the conduit 192 with the compressor 174 positioned upstream from the oxygen supply reservoir 166. A flow control valve 180 positioned upstream from the compressor 174 is configured to stop the flow of oxygen to the compressor 174 from the oxygen separations unit 154. A flow control valve 182 positioned downstream from the oxygen supply reservoir 166 is configured to stop the flow of oxygen to the cell 100 from the oxygen supply reservoir 166 or, in the case of charging of the cell 100, from the cell 100 to the oxygen supply reservoir 166.

[0045] The conduit 194 branches off from conduit 192 downstream from the oxygen separations unit 154 and upstream from the flow control valve 180 and then rejoins the conduit 192 downstream from the flow control valve 182 and before the conduit 192 is coupled to the cell 100. The optional blower 190 is disposed along the conduit 194. The blower 190 is used to increase the pressure of the oxygen coming out of the oxygen separations unit 154 such that it flows easily through the cell 100. In one embodiment, the blower increases the pressure of the oxygen coming from the oxygen separations unit to 2 bar. A flow control valve 184 is positioned upstream from the blower 190 and a flow control valve 186 is positioned downstream from the blower 190. The flow control valves 184 and 186 are configured to stop the flow of oxygen through the conduit 194 and the blower 190.

[0046] In the operating state in which the oxygen management system 150 supplies oxygen to the cell 100 from only the oxygen separations unit 154, the battery management system 306 closes the valves 180 and 182 and opens the valves 184 and 186. This valve configuration enables oxygen to flow from the oxygen separations unit 154 through the conduit 194 and through the end of the conduit 192 and into the cell 100. There is no oxygen flow to the compressor 174 or from the oxygen supply reservoir 166 when the valves 180 and 182 are closed. As noted above, the oxygen management system 150 can operate the blower 190 to increase the pressure of the oxygen supplied to the cell 100, if needed.

[0047] In the operating state in which the oxygen management system 150 supplies oxygen to the oxygen supply reservoir 166 from the oxygen separations unit 154, and no oxygen is supplied to the cell 100, the battery management system 306 closes the valves 182, 184, and 186 and opens the valve 180. This valve configuration enables oxygen to flow from the oxygen separations unit 154 to the compressor 174 and to the oxygen supply reservoir 166. There is no oxygen flow through the conduit 194 to the cell 100 or from the oxygen supply reservoir 166 to the cell 100 when the valves 182, 184, and 186 are closed. The compressor 174 in this embodiment receives oxygen from the oxygen separations unit 154 and compresses the oxygen for storage in the oxygen supply reservoir 166.

[0048] In the operating state in which the oxygen management system 150 supplies oxygen to both the cell 100 and the oxygen supply reservoir 166 from the oxygen separations unit 154, the battery management system 306 closes the valve 182 and opens the valves 180, 184, and 186. This valve configuration enables oxygen to flow from the oxygen separations unit 154 through the conduit 194 and through the end of the conduit 192 and into the cell 100 and further enables oxygen to flow from the oxygen separations unit 154 to the compressor 174 and to the oxygen supply reservoir 166. There is no oxygen flow from the oxygen supply reservoir 166 to the cell 100 when the valve 182 is closed.

[0049] In the operating state in which the oxygen management system 150 supplies oxygen to the cell 100 from only the oxygen supply reservoir 166, the battery management system 306 closes the valves 180, 184, and 186 and opens the valve 182. This valve configuration enables oxygen to flow from the oxygen supply reservoir 166 through the remaining portion of the conduit 192 and into the cell 100. There is no oxygen flow through the conduit 194 to the cell 100 or from the oxygen separations unit 154 to the compressor 174 when the valves 180, 184, and 186 are closed. In this configuration, the flow of oxygen from the oxygen supply reservoir 166 to the cell 100 presumes that the oxygen supply reservoir 166 is charged with sufficient pressure for the rate and duration of oxygen flow needed for the given discharge power of the cell 100.

[0050] In the operating state in which the oxygen management system 150 supplies oxygen to the cell 100 from both the oxygen separations unit 154 and the oxygen supply reservoir 166, the battery management system 306 closes the valve 180 and opens the valves 182, 184, and 186. This valve configuration enables oxygen to flow from the oxygen supply reservoir 166 through the remaining portion of the conduit 192 and into the cell 100 and also enables oxygen to flow from the oxygen separations unit 154 through the conduit 194 and through the end of the conduit 192 and into the cell 100. There is no oxygen flow from the oxygen separations unit 154 to the compressor 174 when the valve 180 is closed.

[0051] In the operating state in which the oxygen management system 150 supplies oxygen to the cell 100 from both the oxygen separations unit 154 and the oxygen supply reservoir 166, and simultaneously supplies oxygen to the oxygen supply reservoir 166 from the oxygen separations unit 166, the battery management system 306 opens the valves 180, 182, 184, and 186. This valve configuration enables oxygen to flow from the oxygen separations unit 154 through the conduit 194 and through the end of the conduit 192 and into the cell 100. This valve configuration also enables oxygen to flow from the oxygen supply reservoir 166 through the remaining portion of the conduit 192 and into the cell 100 and enables oxygen to flow from the oxygen separations unit 154 to the compressor 174 and to the oxygen supply reservoir 166. In some embodiments, the flow control valves 182 and 186 are embodied as a single valve positioned downstream from the oxygen supply reservoir 166 and the blower 190. For instance, in some embodiments, the flow control valves 182 and 186 are embodied as a single, 4-position shuttle valve that enables the valve to selectively place one or both of the oxygen supply reservoir 166 and the oxygen separations unit 154 in fluid communication with the positive electrode 116 in some positions. In other positions of the 4-position shuttle valve, the oxygen supply reservoir 166 and the oxygen separations unit 154 are not in fluid communication with the positive electrode 116.

[0052] In one embodiment of the oxygen management system 150, the oxygen supply reservoir 166 can store the oxygen at a higher pressure than an operating pressure of oxygen in the cell 100. For example, the oxygen supply reservoir 166 can store the oxygen in a range of 20 to 500 bar, while the cell 100 is configured to accept the gas at a pressure of 1 to 10 bar. The increased pressure of the oxygen can promote efficient operation of the cell 100 up to a certain pressure level. For example, operating the electrochemical cell 100 at a pressure of greater than one bar (atmospheric pressure at sea level) can help prevent delamination of the Li metal electrode from its protection layers. The elevated pressure can also reduce mass-transport limitations in the positive electrode and thereby increase the limiting current by increasing the chemical potential of oxygen. At higher pressures of oxygen, the amount of oxygen dissolved in the electrolyte and the driving force for oxygen transport to the reaction site is increased. If the pressure is increased to excessive levels, however, then the oxygenated gas can damage the cell 100. Consequently, a pressure regulating device (not shown) in one embodiment can be provided in the conduit 192 before the oxygen is supplied to the cell 100.

[0053] In the embodiment depicted in FIG. 4, the vehicle battery system 300 includes a gas outlet valve 196 coupled to the cell 100. The battery management system 306 can open the gas outlet valve 196 during discharge to exhaust any unconsumed oxygen form the cell 100. Also during discharge, the battery management system 306 can close the gas outlet valve 196 with the oxygen flow rate controlled such that such that the cell 100 consumes all of the available oxygen or the oxygen is “dead-ended”.

[0054] In addition to controlling the on-off state of the valves 180, 182, 184, and 186 as described above, the battery management system 306 in some embodiments can operate the valves 180, 182, 184, and 186 to control the oxygen flow rate to the cell 100. In these embodiments, the battery management system 306 is configured with one or more flow sensors (not shown) and can adjust the valves 180, 182, and 186 while oxygen is flowing through the conduits 192 and 194 based on the flow rate measured by the flow sensors.

[0055] During discharge, the cell 100 is connected to an electrical load via a first electrical circuit 208. The electrical load can include a vehicle drivetrain, a variety of vehicle electronics, the oxygen separations unit 154, the compressor 174, and the blower 190. For simplicity all such loads are represented by a single resistor 210 in FIG. 4.

[0056] To charge the cell 100, a power supply 212 provides power to the cell 100 via a second electrical circuit 214. During a charge cycle, the positive electrode 104 generates a volume of gas, including oxygen, with the oxygen originating from the reaction products formed during the discharging process. For example, it is believed that reaction products that include oxygen such as Li.sub.2O.sub.2 and Li.sub.2O can be formed in the electrode 104 during discharge of the cell 100.

[0057] During the charging process, electrical current flows through the positive electrode 104 and the reaction products disassociate, with the oxygen returning to a gas phase. The gaseous oxygen builds within the positive electrode 104 and generates a positive pressure. The battery management system 306 closes the valves 182 and 186, which are shown as the valves closest to the inlet of the cell 100, and opens the gas outlet valve 196 to prevent gases from accumulating in cell 100 to an unsafe level. In some embodiments, the battery management system 306 can open the valve 180 to enable the oxygen separations unit 154 and the compressor 174 to fill the oxygen supply reservoir 166 while simultaneously charging the cell 100. In this case, the power supply 212 provides power to the oxygen separations unit 154 and the compressor 174, as well as the cell 100.

[0058] FIG. 4 illustrates the first electrical circuit 208 and the second electrical circuit 214 with respective switches 216 and 218 in their open states. No charging or discharging of the cell 100 occurs when the circuits 208 and 214 are in the open state. For discharging of the cell 100, the battery management system 306 places the switch 216 in the closed state and places the switch 218 in the open state. For charging of the cell 100, the battery management system 306 places the switch 216 in the open state and places the switch 218 in the closed state. While the vehicle battery system 300 has been described as including a battery management system 306 to control the various components of the system, other embodiments of the vehicle battery system can implement other forms of open loop or closed loop control with or without use a battery management system.

[0059] While the disclosure has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the disclosure are desired to be protected.