SIPHON BREAK FOR REDOX FLOW BATTERY

1 . A redox flow battery comprising:

a battery housed in a substantially closed housing having at least first and second internal containers, wherein the first and second containers are in fluid communication with each other, and wherein the first container is configured for containing a quantity of electrolyte and providing a gas headspace above the electrolyte;

an electrolyte circulation system configured to circulate the electrolyte between the first and second containers; and

an anti-siphon device configured to prevent siphoning between the first and second containers.

2 . The redox flow battery of claim 1 , wherein a second container is configured for containing a quantity of electrolyte and providing a gas headspace above the electrolyte, and a third container is configured for containing cell stacks.

3 . The redox flow battery of claim 1 , wherein the electrolyte circulation system includes a pump.

4 . The redox flow battery of claim 1 , wherein the anti-siphon device includes an anti-siphon conduit connecting at least one high point in the electrolyte circulation system with the head space of one or more of the at least first and second containers.

5 . The redox flow battery of claim 1 , wherein the electrolyte circulation system includes a first container discharge conduit and a first container return conduit.

6 . The redox flow battery of claim 5 , wherein the anti-siphon device includes a first anti-siphon conduit connecting the first container discharge conduit with the first container head space and a second anti-siphon conduit connecting the first container return conduit with the first container head space.

7 . The redox flow battery of claim 2 , wherein the electrolyte circulation system includes a first container discharge conduit and a first container return conduit that connects with the cell stack, a second container discharge conduit and a second container return conduit that connects with the cell stack, and at least one anti-siphon conduit connecting one or more of the discharge and return conduits with the tank head space of one or more of the at least first and second containers.

8 . The redox flow battery of claim 6 , wherein the sizing of the first and second anti-siphon conduits controls the liquid flow rate through the first and second anti-siphon conduits and the amount of time required to break a siphon.

9 . The redox flow battery of claim 1 , wherein the anti-siphon device is passively operated.

10 . The redox flow battery of claim 1 , wherein the anti-siphon device does not include a valve.

11 . The redox flow battery of claim 1 , wherein the anti-siphon device includes a passively operated valve to control the liquid control flow rate and or the amount of time required to break a siphon.

12 . The redox flow battery of claim 1 , wherein the anti-siphon device is actively operated.

13 . The redox flow battery of claim 1 , wherein the anti-siphon device includes an actuated valve to control the liquid control flow rate and or the amount of time required to break a siphon.

14 . A redox flow battery comprising:

a first tank configured for containing a quantity of electrolyte;

a second tank configured for containing a quantity of a electrolyte;

an electrolyte circulation system configured to circulate the electrolyte between the first and second tanks and a cell stack; and

an anti-siphon device configured to prevent siphoning between the tanks and cell stack.

15 . A redox flow battery comprising:

an anolyte storage tank configured for containing a quantity of anolyte and an anolyte headspace;

a catholyte storage tank configured for containing a quantity of a catholyte and a catholyte headspace;

an electrolyte circulation system configured to circulate the electrolyte between the anolyte and catholyte storage tanks and a cell stack; and

an anti-siphon device configured to prevent siphoning between the first and second tanks and cell stack.