|Panasonic module. Click to enlarge.
Panasonic Corporation has developed 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), the company suggests.
The module has a volume of approximately 7 liters and weighs 8 kg. Voltage is 25.2V with a capacity of 58 Ah. A prototype will be shown at CEATEC JAPAN 2009 (Makuhari Messe, 6-10 October 2009) and New Energy Industry Fair Osaka (Intex Osaka, 7-9 October 2009).
The high-energy module is constructed from 140 18650-type lithium-ion battery cells—seven serially connected rows with each row made of 20 parallel connected battery cells. This structure allows for avoiding serious loss in the system performance such as system shutdown even if some individual cells fail, Panasonic says.
To build the module, Panasonic employed a high-capacity and high-durability cell technology using its proprietary nickel-based cathode material (LiNiO2). Other technologies used include its cell safety technology that uses a heat-resistant metal oxide insulating layer between the positive and negative electrodes to prevent short circuits and thermal runaway which can be caused when foreign particles get mixed into the battery cell. The new module also uses Panasonic's design technology to ensure reliability by minimizing the effects on power supply if a trouble occurs in some of the cells contained in the module.
Panasonic holds 38 patents in Japan and 22 in other countries including pending applications on the new module.
Development of High Specific Power Lithium Ion Batteries (Matsushita Technical Journal, August 2006)