Showa Denko K.K. (SDK) and Showa Denko Packaging Co., Ltd. (SPA) will start volume production of carbon-coated aluminum foils that reduce electrical resistance of lithium-ion battery (LIB) electrodes.

When compared with conventional plain aluminum foils, the product, sold under the trade name of SDX™, can reduce contact resistance by approximately 50%.  This will substantially improve quick charge/discharge performance required for collectors in automotive LIBs.

SDK has been providing SDXTM to a limited number of customers, making efforts to improve its quality.  In view of the customers’ high valuation of the product, SDK has decided to start its full-scale sales.  SDK aims to achieve SDX™ sales of 5 billion JPYin 2015.

An LIB has a device at each electrode for collecting and taking out electricity.  In this device, called a collector, aluminum foils are used for the cathode and copper foils for the anode.

As a cathode material for large LIBs, olivinic lithium ferrous phosphate (LFP) is attracting keen attention due to its high safety and long life.  However, LFP has high electrical resistance, resulting in high contact resistance* with regard to plain aluminum foils used as a collector.  Due to this high contact resistance, LIBs can generate heat at the time of quick charge/discharge.  Furthermore, LFP has poor adhesion to plain aluminum foils, making it difficult to uniformly coat a cathode material.

SDX™ is produced by coating plain aluminum foils with electrically conductive carbon, using our proprietary technology.  The product reduces contact resistance between a cathode material and a collector by approximately 50%.  As a result of the substantial reduction in contact resistance, rate performance* has improved by more than 30%, enabling quick charge/discharge of heavy current.  In addition, adhesion to collectors has increased, to 1.5 times the conventional level.  This would lead to improvement in productivity at customers.  SDXTM has been adopted in part of large-LIB electrode production.

The Showa Denko Group has selected “Environment/Energy” and “Electronics” as its major business domains under the new medium-term consolidated business plan PEGASUS, promoting the supply of advanced components, materials and solutions.  SDK’s Advanced Battery Materials Department, which handles development, production and sale of components for LIBs and fuel cells, will accelerate R&D and commercialization in these areas, fully utilizing the Group’s rich stock of inorganic, aluminum and organic chemical technologies.

Contact resistance: The term generally refers to a voltage drop that occurs when electricity passes through two different conductors.  In this case, it refers to resistance that occurs between a cathode material and a collector.  The level of contact resistance is in proportion to electrical resistance of a cathode material.
Rate performance: The term refers to rates at which a battery’s capacity is maintained with the change in electric current.  As the rate performance increases, the battery can withstand quicker charge and discharge.

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