Patent CN215696773U - Three-Roll Electrode Calender

Roll pressing is an indispensable step in manufacturing lithium battery electrode sheets. But the specification of CN215696773U states the problem bluntly: the roller presses then in use for electrode sheets are often structurally unstable, and during rolling an unstable press can damage the electrode sheet and waste raw material. Instead of adding more bracing to a single-nip machine, this patent changes the geometry of the roll set itself.

CN215696773U, filed on 2 September 2021 and granted on 1 February 2022, arranges three press rolls in a triangle - two lower rolls on the workbench and a third roll carried in a liftable calender cover above them. Around that triangle it adds roll-surface cleaning, a synchronized take-up and matched height limiting at both ends of the pass, so the electrode is rolled flat, clean and under steady tension.

Patent Information

The Production Problem This Patent Solves

Unstable structures damage the electrode. In the electrode sheet manufacturing process, calendering (roll pressing) is essential. With the presses previously in use, an unstable machine structure lets the electrode sheet shift or distort during rolling, damaging the sheet and wasting raw material.

A single nip leaves no margin for error. A conventional two-roll press squeezes the electrode in one nip between one upper and one lower roll. The patent instead holds the electrode between two lower rolls with a third roll pressing from above, spreading the load over a triangular geometry that stays stable through the whole pass.

Contamination and tension are also rolling defects. Debris stuck to the roll faces can be pressed into the electrode, and uneven tension between rolling and winding can stretch or tear the finished web. The patent treats both as part of the same machine design problem, not as separate accessories.

How the Mechanism Works

Triangular three-roll geometry (claims 1 and 4)

The workbench carries a rolling groove in its middle. Inside it, a first press roll on a first roll shaft and a second press roll on a second roll shaft form the lower pair. The calender cover above the workbench contains a cover cavity that carries the third roll shaft and the third press roll. The third press roll cooperates with the two lower press rolls to form a triangular rolling structure - the electrode web is guided over the two lower rolls while the closing top roll presses down from above. The specification states that this triangular arrangement makes the rolling process more stable and increases rolling uniformity.

Synchronized roll drive (claim 2)

Inside the rolling motor box at the front of the workbench, the rolling motor drives a first gear, which meshes with a second gear and then a third gear keyed to the first roll shaft. A rolling drive belt couples the third gear to a fourth gear keyed to the second roll shaft. With this chain of gear meshing plus belt transmission, both lower press rolls keep exactly the same rotational speed, which the specification credits with improving the rolling effect.

Continuous roll-surface cleaning (claims 3 and 5)

Two rolling brushes are fixed to the inner wall of the rolling groove and cooperate with the first and second press rolls, wiping residue off the roll faces as they turn. Below the groove, a perforated filter plate lets loosened debris drop into an impurity collecting trough underneath. A protection box on the far side of the motor box carries an impurity collection port that opens through the trough, so the cleaned-off residue is collected and drained away rather than re-entering the nip.

Liftable calender cover with electric cylinders (claim 6)

Four telescopic shafts under the calender cover are driven by electric cylinders housed in the protection box and the rolling motor box and wired to the controller. The cylinders raise and lower the whole cover - including the third press roll - so loading the electrode web between the rolls is quick and convenient. Shaft seals on both lower roll shafts protect the journals.

Synchronized glue-start take-up (claims 7 and 8)

At the left end of the workbench a take-up motor box drives a take-up shaft through a fifth and sixth gear pair. The take-up motor is wired to the same controller as the calender motor, so take-up speed tracks rolling speed and the rolled electrode is not pulled or stretched. A clamping groove on the take-up shaft is coated with adhesive, so the web start is anchored firmly for tight, even winding.

Height limiting at feed and take-up (claims 1, 7 and 8)

A feed trough at the right end of the workbench holds a feed shaft and a feed height-limiting rod; a matching take-up height-limiting rod sits at the take-up side, at exactly the same height. Both rods are made of polished, electroplated steel. The electrode is threaded over the feed rod, through the rolls and over the take-up rod, so it stays horizontal before and after rolling - a further contribution to rolling stability.

Claimed Benefits

How It Compares with Two-Roll Electrode Calenders

The specification warns that with the presses previously in use an unstable machine structure lets the electrode sheet shift or distort during rolling, damaging the sheet and wasting raw material. The answer here is geometric: three press rolls arranged as a triangle.

Where This Technology Is Used Today

This patent covers the mechanical architecture of the triangular-roll electrode calenders in TOB's production line. The geometry it protects - two lower rolls plus a closing top roll in a triangle, with cleaning brushes and a synchronized take-up - is how our calendering equipment keeps electrode rolling stable, clean and even.

• Electrode roller presses and calendering equipment
• Electrode preparation equipment

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Full specification and drawings: CN215696773U on Google Patents

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