Apple innovation in battery materials
Apple a leader in consumer electronics innovation, has developed new technology in battery materials. The company started patenting battery materials in 2013, and its activities increased over the last five years (shown in the Table) and it has published 36 patent families for pouch cells used in electronic devices. According to BattScout's patent analysis, Apple's patent portfolio in battery material has six sections: Cathode materials, liquid electrolytes, silicon anodes, solid-state electrolytes, separators, and lithium metal anodes. Most patents have been registered on cathodes, liquid electrolytes, and lithium metal anodes.
Patent timeline by technologies
Among various cathode materials, the use of High-capacity ternary cathodes (such as NMC cathodes) for their high energy density is common in electronic devices application. Apple has introduced a multilayer cathode with a nickel-rich core and protective layers synthesized via the conventional coprecipitation method. As these materials suffer from low-stability capacity, Nickel-rich cathode particles as the core are coated by two layers as a solution. The first is a cathode material with low-containing nickel, and the second is a metal oxide layer containing Al, Ti, Zr, or lanthanum oxides. It is worth mentioning that the coating of solid-state electrolytes layer on NCM particles causes to decrease in gassing phenomena on the cathode side.
Lithium metal, with the most energy density among anode materials, is another focusing point of Apple battery technology. Apple solves the short circuit problem by using a porous structure of lithium metal, providing enough space for lithium to expand during battery charge/discharge and also coating the surface with a film of LIPON solid-state electrolyte to prevent dendrite growth. The company also uses a graphene layer deposited on copper foil to reduce the corrosion of lithium metal in contact with the copper current collector, which is another way to use lithium metal as the anode.
The company's patents mainly consider modifying electrolyte composition for high voltage cathodes and enhancing thermal stability in electrolyte and separator sections. Apple introduced a cell with two different electrolytes separated by a membrane which can hinder the gassing issue.
Apple has developed all these technologies to improve battery capacity. Battery capacity has been an edge of Apple technologies in the consumer electronics market compared to Xiaomi and Samsung, so Apple is planning to use it to fill its gap in the share market.
