TECHNOLOGY FOCUS - POLYMERS - Preferred Device: The film coating slurry comprises polyvinylidene fluoride, silicon dioxide-aluminum oxide ((SiO2)(Al2O3)), butanone, normal butanol and diethyl carbonate. The temperature control device comprises a first heating mechanism used for heating the slurry groove to conveniently control the temperature of the film coating slurry in the slurry groove in the pre-set range and a second heating mechanism or a temperature heating mechanism for heating or keeping the temperature of the film coating head to keep the temperature of the film coating slurry at the film coating head. The temperature control device comprises a first heating mechanism used for heating the slurry groove to conveniently control the temperature of the film coating slurry in the slurry groove in a range of 30-80 degrees C and a second heating mechanism or a temperature heating mechanism for heating or keeping the temperature of the film coating head to keep the temperature of the film coating slurry at the film coating head. The temperature control device further comprises a third heating mechanism or a temperature keeping mechanism used for heating or keeping the temperature of the slurry convey tube (2) to keep the temperature of the film coating slurry at the film coating head. The film coating head (3) has a film coating seam with adjustable length and/or width. The device further comprises a sheet convey device (8) composed of a sheet convey rack and a power roll, a sheet receiving device composed of a sheet receiving rack and a power roll and a pole piece jump coating device for realizing the jump of the pole piece coating via a positioning sensor (11). Preferred Method: In the method, the film coating slurry comprises polyvinylidene fluoride, SiO2(Al2O3), butanone, normal butanol and diethyl carbonate; and in the step of providing the film coating slurry to the slurry groove, the first heating mechanism is used for heating the slurry groove to keep the temperature of the film coating slurry in the slurry groove in a range of 30-80 degrees C; in the step of using the film coating head to process film coating to the lithium ion battery pole piece, the second heating mechanism or the temperature keeping mechanism heats or keeps the temperature of the film coating slurry, whose viscosity is between 10 mPa.seconds and 100 mPa.seconds. The length and/or width of the film coating head seam of the film coating head is adjusted before the film coating.