IEC 62391-2:2006

Overview

IEC 62391-2:2006 is the sectional specification from the IEC for fixed electric double‑layer capacitors (EDLCs) - commonly called supercapacitors - intended for power applications. It complements the generic rules in IEC 62391-1 by defining preferred ratings, characteristics and the appropriate quality‑assessment procedures, tests and measurement methods for capacitors designed to deliver discharge currents in the range from mA to A. Key traits covered include relatively high capacitance, low internal resistance (low ESR) and guidance for calculating power density (see Annex A).

Key topics and technical requirements

• Scope and object: Applies to EDLCs for power use; aligns with Class 3 measurement classification of IEC 62391-1. Detail specifications must meet or exceed the severities in this sectional specification.
• Preferred ratings & characteristics: Recommended capacitance, voltage ranges and preferred values for design and procurement (detail specifications derive from this).
• Quality assessment procedures: Primary manufacture checks, structurally similar component rules, declaration of conformity, initial assessment and ongoing quality conformance.
• Test and measurement procedures: Defined methods include (but are not limited to)
  • preliminary drying and standard measuring conditions
  • visual examination and dimensional checks
  • electrical tests (capacitance, ESR, leakage/self‑discharge)
  • robustness of terminations, resistance to soldering heat, solderability
  • environmental tests: rapid temperature change, vibration, damp heat, storage at high temperature, characteristics at high/low temperature
  • endurance, passive flammability and pressure relief (where applicable)
• Marking and terminology: Required marking elements (polarity, rated capacitance, rated voltage) and standardized terminology for surface‑mount and power EDLCs.
• Power density: Definition and calculation procedure provided in Annex A for consistent performance comparison.

Applications and who uses this standard

IEC 62391-2 is relevant to:

• Supercapacitor manufacturers - to set product design limits, test schedules and detail specifications.
• Test and qualification laboratories - to perform standardized measurements and quality assessments.
• Product designers and power‑electronics engineers - selecting EDLCs for backup power, energy buffering, peak‑shaving, regenerative braking, and pulsed‑power applications.
• Purchasing and compliance teams - ensuring components meet required ratings and test severities for safety and reliability.

Related standards

• IEC 62391-1 (Generic specification) - primary reference for measurement classification and basic definitions
• IEC 62391-2-1 (Assessment level EZ)
• Other referenced documents used for environmental testing, sampling and preferred numbers: IEC 60068-1, IEC 60063, IEC 60384-1, IEC 60410, and ISO 3.

Keywords: IEC 62391-2, electric double‑layer capacitors, EDLC, supercapacitor, power application, low ESR, capacitance, quality assessment, testing, power density, IEC 62391-1.