Solid electrolytic capacitor element

Abstract

A solid electrolytic capacitor element that is capable of withstanding laser welding without a significant deterioration in its electrical performance is provided. The capacitor element contains an anode body, dielectric, and solid electrolyte. To help shield the solid electrolyte from damage that might otherwise occur during manufacture of the capacitor, a multi-layered protective coating is employed in the present invention that overlies at least a portion of the solid electrolyte. More particularly, the protective coating includes a light reflective layer overlying the solid electrolyte and a stress dissipation layer overlying the light reflective layer. The light reflective layer can help reflect any light that inadvertently travels toward the capacitor during, for example, laser welding. This results in reduced contact of the solid electrolyte with the laser and thus minimizes defects in the electrolyte that would have otherwise been formed by carbonization. The stress dissipation layer can likewise help to dissipate stresses experienced by the capacitor (e.g., during encapsulation, reflow, etc.) so that they are not as likely to cause damage to the solid electrolyte. The stress dissipation layer can also be relatively porous in nature so that humidity trapped in the capacitor can escape and diminish the pressure that might otherwise be transferred to the solid electrolyte.