IEC 62973-2:2020

Overview - IEC 62973-2:2020 (NiCd batteries for railway rolling stock)

IEC 62973-2:2020 is the International Electrotechnical Commission standard that specifies requirements for Nickel Cadmium (NiCd) rechargeable batteries used as auxiliary power supplies on railway vehicles (rolling stock). It is a technology‑specific extension of IEC 62973-1:2018, which defines common requirements for battery systems in railway applications. IEC 62973-2 covers design, operational parameters, safety guidance, marking and designation, plus routine and type testing for NiCd battery systems. Charging systems (LVPS, converters, etc.) are excluded from its scope.

Key topics and technical requirements

• Battery types and constructions: Definitions and characteristics of NiCd cells, monoblocs, crates, trays and battery boxes, and electrode/plate technologies (e.g., sintered, fibre, pocket).
• System requirements: Guidance on system voltage, charging and discharging behaviour, charge retention (self‑discharge), and battery capacity sizing for auxiliary loads.
• Charging characteristics: Required charge regimes, temperature compensation during charging, and interactions with onboard charging systems (charging equipment itself is out of scope).
• Safety and protection: Recommendations on deep discharge protection, thermal management, fire protection and required safety signs/markings.
• Mechanical and environmental design: Mounting, accessibility, shock and vibration resistance, ventilation and water filling systems appropriate for rolling stock environments.
• Testing and verification: Type tests and routine tests for electrical characteristics, dielectric strength, load profile verification, shock/vibration and documentation of test results. Annexes provide typical load profiles and a normative methodology for load profile verification.
• Maintenance, storage and transport: Requirements and recommended practices for safe storage, transportation and periodic maintenance.

Practical applications

IEC 62973-2:2020 is used to ensure NiCd battery systems for auxiliary functions (lighting, control circuits, emergency systems, communications, etc.) are safe, reliable and interoperable in railway vehicles. It supports:

• Battery system design and validation for new rolling stock
• Procurement specifications for NiCd battery suppliers
• Type approval, testing and commissioning procedures
• Operation and maintenance planning for fleet engineers and depot teams

Who should use this standard

• Rolling stock designers and system integrators
• Battery manufacturers and cell/monobloc suppliers
• Railway operators, maintenance engineers and depot personnel
• Test laboratories, certification bodies and procurement teams

Related standards

• IEC 62973-1:2018 - Common requirements for railway battery systems
• IEC 60623:2017 and IEC 62259:2003 - Standards referenced for NiCd cell specifications
• Other parts of the IEC 62973 series for different battery technologies

Keywords: IEC 62973-2:2020, NiCd batteries, railway rolling stock, auxiliary power supply, battery testing, charging characteristics, battery safety.