Nickel–cadmium battery

Nickel–cadmium battery
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Name	Nickel–cadmium battery
Other names	Ni–Cd; NiCd
Type	Rechargeable battery
Electrode materials	Nickel oxyhydroxide; Cadmium
Electrolyte	Potassium hydroxide
Developed	1899
Inventor	Waldemar Jungner

Nickel–cadmium battery is a type of rechargeable cell that uses Waldemar Jungner, Alfred René Gueissaz, and later industrial developers to commercialize a technology characterized by a nickel oxyhydroxide positive electrode and a cadmium negative electrode in an aqueous potassium hydroxide electrolyte. Widely adopted through the 20th century, Ni–Cd cells powered consumer electronics, aviation, and portable tools and competed with lead–acid battery, nickel–metal hydride battery, and lithium-ion battery chemistries. The chemistry, mechanical design, and regulatory attention around cadmium have shaped standards set by organizations such as International Electrotechnical Commission and legislation in jurisdictions like the European Union and the United States.

History

Early scientific work on rechargeable electrochemical systems involved inventors including Waldemar Jungner and contemporaries who explored alternatives to the Daniell cell and the Leclanché cell. Industrialization in the 20th century engaged firms such as Saft (company), Electrolux, and later Energizer Holdings, resulting in sealed rechargeable forms used by British Royal Air Force and United States Navy for radio and emergency lighting. Military and aerospace programs like Northrop Grumman, Boeing, and NASA's Apollo program adapted Ni–Cd packs for robust operation in extreme environments. Environmental scrutiny in the late 20th and early 21st centuries, prompted by advocacy from groups linked to Greenpeace and regulations from the European Commission and Environmental Protection Agency, accelerated shifts toward alternative chemistries and recycling initiatives.

Chemistry and construction

The electrochemical system combines a nickel oxyhydroxide (NiO(OH)) positive electrode and a cadmium (Cd) negative electrode immersed in a concentrated potassium hydroxide (KOH) electrolyte, a design refined by laboratories at institutions like Imperial College London and industrial research centers at General Electric. Cells are manufactured in formats standardized by organizations including International Electrotechnical Commission and American National Standards Institute, yielding cylindrical, prismatic, and button cells used by Sony, Panasonic, and Duracell. Construction variants include vented flood cells used in industrial backup systems and sealed cells with pressure relief valves applied in consumer packs for Nokia phones and portable tools from Black & Decker. Separator materials, current collectors, and sintered plate technologies evolved under patents held by companies such as Saft (company) and Sanyo Electric Co..

Performance and characteristics

Ni–Cd cells exhibit stable discharge voltage and robust cycle life; electrical characteristics were specified in technical standards from IEEE and operational guidelines used by Airbus and Boeing for avionics batteries. Compared with lead–acid battery and nickel–metal hydride battery, Ni–Cd offers high charge acceptance, wide operating temperature range referenced in military standards from Defense Logistics Agency, and resilience to deep discharge. Ni–Cd cells present a memory effect observed in early portable devices like Sony Walkman players and addressed by charge management practices promoted by manufacturers including Motorola and Philips. Energy density is lower than lithium-ion battery, while internal resistance and self-discharge rates informed designs by RCA Corporation and Texas Instruments for standby power. Standard tests referenced by Underwriters Laboratories measure capacity, impedance, and cycle durability.

Applications

Historically Ni–Cd batteries were specified for aerospace and defense applications by organizations such as NASA, US Air Force, and NATO for avionics, emergency lighting, and portable communications. Industrial uses included uninterruptible power supplies in facilities operated by Siemens and backup power in telecommunications networks managed by AT&T and Verizon. Consumer electronics from companies like Panasonic, Sony, and Motorola used Ni–Cd cells in cordless phones, power tools from DeWalt and Makita, and two-way radios by Kenwood. Medical devices regulated by agencies such as Food and Drug Administration have employed Ni–Cd packs where reliability under sterilization protocols was required. Specialty cells remain in niche roles for railway signaling equipment and certain military hardware maintained under procurement contracts by US Department of Defense.

Environmental impact and recycling

Cadmium is a toxic heavy metal subject to controls under international conventions and national laws such as the Basel Convention, directives from the European Commission (including the Restriction of Hazardous Substances Directive), and regulations enforced by the Environmental Protection Agency. Collection programs operated by industry groups including Call2Recycle and manufacturers like Energizer and Duracell recover Ni–Cd cells for metallurgical recycling in facilities certified by ISO standards. Recycling processes recover cadmium and nickel for reuse in alloys and new battery production at smelters associated with companies such as Glencore and Umicore. Lifecycle assessments by research institutions including Fraunhofer Society and Lawrence Berkeley National Laboratory compare environmental burdens of Ni–Cd with nickel–metal hydride battery and lithium-ion battery chemistries, influencing policy decisions by national ministries and municipal waste authorities.

Safety and handling

Safe handling follows standards and guidance from Underwriters Laboratories and national occupational safety agencies like the Occupational Safety and Health Administration for workplaces that store or service Ni–Cd batteries. Risks include leakage of alkaline electrolyte and exposure to cadmium dust; remediation and first-aid procedures are detailed in industrial hygiene protocols used by Johnson Controls and ABB. Transport of Ni–Cd cells is regulated under frameworks such as the International Air Transport Association Dangerous Goods Regulations and the United Nations model regulations for hazardous materials. Manufacturers and institutions like IEEE publish charging, storage, and disposal recommendations to minimize thermal runaway, venting, and environmental release.

Category:Battery types