Panasonic Develops New Higher-Capacity 18650 Li-Ion Cells; Application of Silicon-based Alloy in Anode
25 December 2009
Panasonic Corporation announced the development of two new 18650-type (18 mm in diameter, 65 mm in height) high-capacity lithium-ion battery cells for use in laptop computers and in energy applications including electric vehicles.
The newly-developed high-capacity 3.4 Ah and 4.0 Ah lithium-ion battery cells have an improved nickel-based positive electrode (Panasonic’s proprietary positive electrode material based on LiNiO2, allowing for high capacity and durability). The 4.0 Ah cell uses a silicon-based alloy for the negative electrode instead of carbon, and offers a volumetric energy density of 800 Wh/L, compared to the 620 Wh/L in the current 2.9 Ah cells.
In October, Panasonic Corporation announced a 1.5 kWh battery module from 18650-type (18 mm in diameter x 65 mm in length) lithium-ion battery cells to provide energy storage solutions for a wide range applications. Multiple units can be connected in series and/or parallel to store energy generated by home-use photovoltaic (PV) systems and fuel cells or power electric vehicles (EV). (Earlier post.)
The 3.4 Ah cell offers 20% greater capacity than the current 2.9 Ah model. The 3.4 Ah cell will be mass-produced in fiscal 2012 ending in March 2012. The 4.0 Ah cell, which has 30% greater capacity compared to the 2.9 Ah cell, will be mass produced in fiscal 2013 ending in March 2013. These high-capacity battery cells can be used to build high-energy battery modules.
Panasonic holds 337 patents in Japan and 136 in other countries including pending applications on the new battery cells.
|Panasonic 18650 Li-ion Cells|
|2.9 Ah (current)||3.4 Ah (FY 2012)||4.0Ah (FY 2013)|
|Cathode||Nickel||Enhanced nickel||Enhanced nickel|
|Capacity||2.9 Ah||3.4 Ah||4.0 Ah|
|Avg. discharge voltage||3.6 V||3.6 V||3.4 V|
|Mass||Approx. 44g||Approx. 46g||Approx. 54g|
|Energy capacity||10.4 Wh||12.2 Wh||13.6 Wh|
|Vol. energy density||620 Wh/L||730 Wh/L||800 Wh/l|
|Charging voltage||4.2 V||4.2 V||4.2 V|
Direct Methanol Fuel Cell. Panasonic also announced it has developed a direct methanol fuel cell system which can produce an average power output of 20 W by increasing the output per cubic centimeter twice that of its previous prototype. Using this technology, Panasonic aims to develop a 100 W-class portable generator and start field testing in fiscal 2012 ending in March 2012.
In 2008 Panasonic developed compact fuel cell stacks by reviewing the structure of its connecting parts. It also developed compact and energy-efficient balance of plant (BOP) systems including a fuel supply pump that can directly mix and adjust the concentration of methanol internally. By improving the stack technology, Panasonic has successfully doubled the average power output to 20 W while retaining the same volume with the preceding prototype. The high output methanol fuel cell allows for powering feature-laden laptop computers, which have relatively high power consumption.
The new fuel cell system also boasts 5,000 hours of durability (based on eight-hour intermittent use per day). Durability was a major challenge for commercialization of fuel cells because power output drops as the electrodes deteriorate. Panasonic solved the problem by developing a technology that enables supplying high concentration fuel to the electrode.
Using micro porous layers that control the amount of fuel passing through them, this technology enables supplying highly concentrated fuel to the electrode and suppressing methanol "cross-over" which wastes fuel.
Panasonic holds 139 patents in Japan and 69 in other countries including pending applications on the fuel cell system.
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