Lithium batteries with triple their current capacity could emerge in coming years with Sumitomo Electric Industries set to mass produce its porous Aluminium-Celmet material.
Sumitomo Electric Industries has set up a small-scale production line at its Osaka works to develop mass production of the porous metal, which is made from nickel or nickel chrome alloy.
The porous metal manufacturing process comprises electro conductive coating to plastic foam, followed by nickel plating and plastic foam removal by heat treatment.
With up to 98 percent porosity, Aluminium-Celmet features a 3D mesh-like structure that forms interconnected, open and spherical pores. The metal can be formed into various shapes by cutting and stamping.
These features lead to favourable filling, retaining and current-collecting performance, when used with an active material. As such, the material has recently been adopted as a positive electrode current collector in hybrid vehicle nickel-hydrogen batteries.
Aluminium-Celmet is light, and a great electrical conductor. It is also very resistive to corrosion, and suitable for use in lithium-ion and other secondary batteries operating at high charge/discharge voltages. Aluminium-Celmet can also be used for current collectors in capacitors.
The positive electrode current collector in a conventional lithium-ion secondary battery is made from aluminium foil, while the negative electrode current collector is made from copper foil. Replacing the aluminium foil with Aluminium-Celmet increases the amount of positive active material per unit area.
Sumitomo Electric’s trial calculations indicate that in the case of automotive onboard battery packs, such replacement will increase battery capacity 1.5 to 3 times. Alternatively, with no change in capacity, battery volume can be reduced to one-third to two-thirds. These changes afford such benefits as reduced footprint of home-use storage batteries for power generated by solar and other natural sources, as well as by fuel cells.
In conventional capacitors, both positive and negative current collectors are made from aluminium foil. Use of Aluminium-Celmet instead improves the capacity and reduces the footprint, as with lithium-ion batteries.