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Home > News Room > NEC Develops Manganese Lithium-Ion Batteries with more than

NEC Develops Manganese Lithium-Ion Batteries with more than
Twice the Lifespan of Existing Products

Lithium-Ion Battery

Lithium-Ion Battery

*** For immediate use October 17, 2011

Tokyo, October 17, 2011 - NEC Corporation (NEC; TSE: 6701) announced today the development of technologies that more than double the lifespan of existing rechargeable manganese lithium-ion batteries (*1).

These technologies were realized through a newly developed additive agent for electrolyte solutions in combination with existing manganese positive electrodes / carbon negative electrodes.

Lifespan estimates of batteries using these technologies were carried out testing 3.7 Ah capacity laminated batteries (65 Wh/kg) that were subject to the energy consumption patterns of a typical household (*2). Test results indicate that the number of years it takes for these batteries' recharge capacity to drop to 70% of their original capacity increased from approximately 5 years to 13 years. The number of years for recharge capacity to drop to 50% of their original capacity increased from approximately 15 years to 33 years, more than two times the lifespan.

In addition to household and business use, the durability of these new battery technologies is ideal for large scale electricity storage systems that are used to enhance the stability of electrical power systems.

NEC has a strong history of developing rechargeable lithium-ion batteries with positive manganese electrodes, which provide low cost reserves for a wide range of portable devices.

However, when conventional technologies are used with fixed storage batteries that require high durability and repeated power charging, the solvency of the electrolyte solution degrades and a film begins to form over the negative electrodes. Furthermore, the positive electrode's manganese is gradually dissolved by the electrolyte solution, all of which results in batteries with higher electrical resistance and lower capacity.

Although additive agents with electrolyte solutions have been used to improve the durability of conventional manganese positive electrodes / carbon negative electrodes in the past, this improvement was insufficient for use with fixed storage batteries.

These newly developed batteries resolve durability issues by utilizing original organic sulfur compound additive agents to suppress solvent deterioration and to form a stable protective film on the electrode during charge/discharge cycles. According to baseline assessments (*3) of the newly developed electrolyte solution, the increase in resistance was reduced by more than half, lifespan increased by 1.5 to 3 times and capacity reduction from repeated recharging was significantly restrained.

Furthermore, prototype batteries demonstrated (*4) exceptional durability by maintaining 83% of their original capacity after undergoing 23,500 recharge cycles at room temperature.

In recognition of these accomplishments, the New Energy and Industrial Technology Development Organization (NEDO) is utilizing the underlying technologies for these batteries for the "Development of Safety and Cost Competitive Energy Storage Systems for renewable energy (Fundamental technology development of long-life and safe Mn-type Lithium Ion Batteries for Large Scale Energy Storage Systems)" project that began in July 2011.

Looking forward, NEC will continue to drive innovative new research and development, including the adoption of these new technologies by high density energy cells.

NEC presents the battery lifespan measurement techniques that were used to develop these new technologies on October 18 at the "52nd Battery Symposium in Japan" held in Tokyo from 17 - 20 October 2011.



Compared to NEC batteries using conventional additives for electrolyte solutions in combination with manganese positive electrodes / carbon negative electrodes.


Based on the average energy consumption over a given period of time according to the Architectural Institute of Japan's "Research Panel on Indoor Residential Energy Consumption."


Laboratory level assessment of 18650 cylindrical cells, 2320 coin cells, triode cells, etc. Storage and cycle tests carried out on 18650 cylindrical cells.


Carried out with 3.7 Ah capacity laminated cells. Capacity maintenance rate and resistance improvement based on cycle tests carried out at 25°C, 45°Cand 55°C (full charging in 1 hour, full discharge in 1 hour). Comprehensive evaluation of capacity and resistance improvement based on storage tests carried out at the same temperature (state of charge: 60%).

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NEC Press Contact (Japan)

Joseph Jasper
NEC Corporation

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