Aqueous electrolyte energy storage device

1. An electrochemical device, comprising:

a housing;

a plurality of stacks of electrodes arranged side by side in the housing, each stack comprising an anode electrode, a cathode electrode, and an electrolyte;

a plurality of separator sheets, wherein each separator sheet of the plurality of separator sheets extends continuously between at least two of the plurality of stacks, such that each separator sheet is located between adjacent anode and cathode electrodes of each stack; and

a plurality of current collectors;

wherein:

the housing comprises a hermetically sealed, electrochemically inert polymer housing, and the electrodes in each of the stacks are stacked in a prismatic configuration;

each current collector of the plurality of current collectors extends continuously between at least two of the plurality of stacks;

each separator sheet extends over or under anode boundary areas between adjacent anode electrodes in adjacent stacks;

each separator sheet extends over or under cathode boundary areas between adjacent cathode electrodes in adjacent stack;

each anode current collector of the plurality of current collectors extends between adjacent anode electrodes in each stack, and over and under the anode boundary areas between adjacent anode electrodes in adjacent stacks; and

each cathode current collector of the plurality of current collectors extends between adjacent cathode electrodes in each stack, and over and under the cathode boundary areas between adjacent anode electrodes in adjacent stacks.

2. The electrochemical device of claim 1 , wherein the anode and cathode electrodes are between 0.05 and 1 cm thick, and the current collectors comprise carbon current collectors.

3. The electrochemical device of claim 2 , wherein the current collectors comprise carbon fiber paper, an inert substrate coated with carbon material or exfoliated graphite having a density of greater than 0.6 g/cm 3 .

4. The electrochemical device of claim 1 , wherein the electrochemical device is a hybrid aqueous electrolyte energy storage device.

5. The electrochemical device of claim 4 , wherein the cathode comprises an alkali ion intercalation material and the anode is a pseudocapacitive or electrochemical double layer capacitive material that is electrochemically stable to less than −1.3 V vs. NHE.

6. The electrochemical device of claim 5 , wherein the cathode electrode comprises a doped or undoped cubic spinel λ-MnO 2 -type material or Na 4 Mn 9 O 18 tunnel structured orthorhombic material, the anode electrode comprises activated carbon, titanium oxide material or phospho-olivine material, and the electrolyte comprises sodium ions.

7. The electrochemical device of claim 6 , wherein the electrolyte is an aqueous solution containing dissolved alkali ions that are able to interact with both anode and cathode such that charge may be stored via intercalation at the cathode electrode and by pseudocapacitive non-faradic surface reaction at the anode electrode.

8. The electrochemical device of claim 1 , further comprising a first plurality of tabs operatively connected to the plurality of cathode current collectors and a second plurality of tabs operatively connected to the plurality of anode current collectors.

9. The electrochemical device of claim 2 , wherein:

the anode electrode comprises a pressed granular anode electrode; and

the cathode electrode comprises a pressed granular cathode electrode.

10. The electrochemical device of claim 1 , wherein each separator sheet of the plurality of separator sheets extends continuously between a first stack and a second stack of the plurality of stacks, such that each separator sheet is located between adjacent anode and cathode electrodes of the first stack, and between adjacent anode and cathode electrodes of the second stack.

11. An electrochemical device, comprising:

a housing;

a plurality of stacks of electrodes arranged side by side in the housing, each stack comprising an anode electrode, a cathode electrode, and an electrolyte;

a plurality of separator sheets, such that each separator sheet is located between adjacent anode and cathode electrodes of each stack; and

a plurality of current collectors;

wherein:

each separator sheet extends over or under anode boundary areas between adjacent anode electrodes in adjacent stacks;

each separator sheet extends over or under cathode boundary areas between adjacent cathode electrodes in adjacent stack;

each anode current collector of the plurality of current collectors extends between adjacent anode electrodes in each stack, and over and under the anode boundary areas between adjacent anode electrodes in adjacent stacks; and

each cathode current collector of the plurality of current collectors extends between adjacent cathode electrodes in each stack, and over and under the cathode boundary areas between adjacent anode electrodes in adjacent stacks.

12. The electrochemical device of claim 11 , further comprising a first plurality of tabs operatively connected to the plurality of cathode current collectors and a second plurality of tabs operatively connected to the plurality of anode current collectors.

13. The electrochemical device of claim 12 , wherein:

the anode electrode comprises a pressed granular anode electrode; and

the cathode electrode comprises a pressed granular cathode electrode.

14. The electrochemical device of claim 11 , wherein at least 50% of the anode boundary areas are not aligned with respective cathode boundary areas across the separator sheet.