WE CLAIM:
1. A method for renovation of a consumed anode in a metal-air cell without dismantling the
cell-
circulating electrolyte through the cell to evacuate used slurry from the cell;
5 circulating electrolyte with fresh slurry into the cell and allowing sedimentation of the fresh
slurry inside the cell to form an anode; and
compacting the slurry to reduce the gaps between its particles.
2. The method of claim 1, wherein the compacting of the slurry is carried out by means of
pressurized layer positioned between two adjacent cells.
) 3. The method of claim 2, wherein the pressurized layer is disposed between two adjacent
anode sides of two adjacent cells.
4. The method of claim 2, wherein the pressurized layer is disposed between the anode side of one cell and cathode side of an adjacent cell.
5. The method of claim 2 further comprising applying counter pressure to the cathode side.
5 6. The method of claim 2 further comprising supplying oxygen to the cathode by means of at
least one of perforated balloon, porous layer.
7. The method of claim 2 further comprising controlling the compacting pressure by at least
one of pressure sensor and sensed conductivity between the slurry and the current collector.
8. The method of claim 2 further comprising controlling the cell volume to compensate for
3 the change in volume of the slurry due to transformation from metal to metal-oxide.
9. The method of claim 2 further comprising controlling the conductivity across the slurry to
compensate for the change in conductivity of the slurry due to transformation from conductive
metal to non-conductive metal-oxide.
10. The method of any of the above claims whereas the slurry metal is selected from the list of
5 metals Zn, Fe, Sn, Si and Ge.
11. A meta-air cell enabling renovation of a consumed anode without dismantling the cell
comprising:
porous wall disposed at the cathode outer face of the cell and defining first outer face of the
cell;
) air cathode layer adjacent the porous wall;
separator wall disposed on the inner face of the air cathode layer;

cell space volume to contain electrolyte and metal granules slurry;
current collector layer to form an anode, made of current conductive material disposed in the space; and
flexible wall defining a second outer face of the cell,
wherein the flexible wall is adapted to be pushed towards inside of the cell subject to pressure applied to its outer face, thereby to reduce the volume of the space.
12. The meta-air cell of claim 11 wherein the current collector layer is adapted to allow flow of electrolyte with metal granules slurry through it.
13. The meta-air cell of claim 11 wherein the porous wall is adapted to allow flow of gas containing oxygen through it.
14. The meta-air cell of claim 11 further comprising:
opening in the cell space volume to allow circulating flow of fluid to evacuate used slurry from the cell; and
opening in the cell space volume to allow flow of electrolyte with metal granules slurry to flow into the cell space volume.
15. The apparatus of the above claim 11 whereas the anode is to be renovated by means of compacting metal granules slurry onto the current collector layer.
16. The cell of claim 11 wherein the cell space volume is adapted to contain slurry composition comprising electrolyte, metal particles, metal-oxide particles, additives.
17. A metal-air cell set comprising:
plurality of metal-air cells, each comprising at least:
porous wall disposed at the cathode outer face of the cell and defining first outer face of the cell;
air cathode layer adjacent the porous wall;
separator wall disposed on the inner face of the air cathode layer;
cell space volume to contain electrolyte and metal granules slurry;
current collector layer to form an anode, made of current conductive material disposed in the space; and
flexible wall defining a second outer face of the cell,
wherein the flexible wall is adapted to be pushed towards inside of the cell subject to pressure applied to its outer face, thereby to reduce the volume of the space
an inflatable element disposed between at least two adjacent metal-air cells, adapted to apply pressure onto the flexible wall, therebv to reduce the volume of the cell.

18. The metal-air cell set of claim 17 wherein the inflatable element comprises in a portion of
its outer envelope several cavities to enable flow of gas through them from inside of the
inflatable element out.
19. The metal-air cell set of claim 17 wherein the cells are arranged so that the porous wall of
i one cell faces the flexible wall of the adjacent cell.
20. The metal-air cell set of claim 17 wherein the cells are arranged so that the porous wall of
one cell faces the porous wall of an adjacent cell in one pair of adjacent cells and the flexible
wall of one cell faces the flexible wall of an adjacent cell in another pair of adjacent cells.