A radiofrequency electric current ablation catheter comprising a tip electrode, a means for detecting temperature of the tip electrode, a catheter shaft and a portion for operation at proximal end, wherein the tip electrode has a shape formed by connecting three or more spherical or approximately spherical surfaces having centers on the same straight line to each other with a curved surface. The discrete particles include a plurality of abrasive grits and a polymeric material that includes a reaction product of components including an epoxy-functional material, at least one of a cyclic anhydride or a diacid derived therefrom, and optionally a polyfunctional acrylate. Ring-shaped plate is attached to tip sections of blades. A distribution board has a plurality of interfaces that are strategically positioned to provide a dense configuration. Differences between at least two storage cells with regard to the respective nominal values of one or more of the respective physical properties associated with a storage cell and its actual value at a given time are used to provide additional storage capacity.