The protection circuit against surge did not work in a cell. Two cells I had ordered. One has behaved off when raising the charge voltage to 4.4V. The second cell I could drive up with a laboratory power supply up to 5.2 volts, this then flowed 5 amps. After a few seconds I did the course canceled. But this clearly shows that the protection circuit has failed. One might even conclude that countless supposedly protected cells are in circulation, but merrily on record until the fireworks at current overload (see various YouTube videos).