Method and apparatus for forming electrode for battery

1. A method for forming an electrode for a battery, said method comprising the steps of:

preparing an electrode formed at its surface with a mixture layer containing an active material and

forming a porous layer along the length of the electrode,

the step of forming the porous layer comprising the substep of

rotating a gravure roll oppositely to the direction of movement of the electrode while allowing the gravure roll to abut against the surface of the moving electrode, thereby applying a coating fluid serving as a precursor of the porous layer to the surface of the electrode,

wherein in the substep of applying the coating fluid, part of the coating fluid applied to the surface of the electrode is continuously removed by allowing a scraper to abut against the surface of the electrode, and

a width of a part of the scraper abutting against the surface of the electrode is adjusted according to variations in the width of the porous layer left after the removal of the part of the coating fluid.

2. The method of claim 1 further comprising the steps of:

allowing the scraper to abut against the surface of the electrode, the scraper being provided plural in number, so that the plurality of scrapers abut against a plurality of parts of the surface of the electrode, thereby forming a plurality of linear portions of the porous layer; and

dividing the electrode between adjacent ones of the linear portions of the porous layer.

3. The method of claim 2 , wherein

the mixture layer is divided into a plurality of linear portions along the length of the electrode, and

the plurality of linear portions of the porous layer are formed on the plurality of associated linear portions of the mixture layer.

4. The method of claim 1 , wherein the coating fluid serving as the precursor of the porous layer is a Newtonian fluid.

5. The method of claim 1 , wherein

the scraper is tapered, and

the width of the part of the scraper abutting against the surface of the electrode is adjusted by changing the part of the tapered scraper abutting against the surface of the electrode.

6. The method of claim 1 , wherein

the scraper includes a plurality of scraper portions, and

the width of the part of the scraper abutting against the surface of the electrode is adjusted by changing the width of a part of one of the scraper portions covered with another of the scraper portions.

7. The method of claim 6 , wherein the scraper is made of a material capable of being deformed when the scraper abuts against the surface of the electrode.

8. The method of claim 1 , wherein the step of forming the porous layer further includes the substep of drying the coating fluid applied to the surface of the electrode.