Panasonic achieved the world's highest value of crystalline silicon solar cell conversion efficiency - 25.6%, measured by the Japan Industrial Technology Research Institute. The previous highest value was 25.0%, which was set by the University of New South Wales (UNSW) in March 1999 and has been maintained for 15 years. UNSW's record was achieved with a small unit with an area of ​​only 4cm2, while Panasonic was implemented with a practical size unit of 143.7cm2, which is obviously different from UNSW. For the conversion efficiency of crystalline silicon solar cells with an area of ​​more than 100cm2, the previous highest value was 24.7% released by Panasonic in February 2013, and the cell area was 101.8cm2. In order to increase conversion efficiency, Matsushita decided to substantially change the traditional battery cell structure. The company has previously adopted a cell structure inherited from the Sanyo Electric Machine era, that is, a "heterojunction" in which an amorphous silicon layer is formed on the light-receiving surface and the back surface of a silicon wafer, and electrodes are arranged on the light-receiving surface and the back surface. In this case, the heterojunction on the back surface is preserved and the back contact structure of the light receiving surface electrode is removed. This structure can prevent the electrodes on the light-receiving surface from blocking the incident light, and therefore can increase the amount of current. The short-circuit current density was increased to 41.8 mA/cm2, and the short-circuit current density of the unit released by Panasonic in February 2013 was 39.5 mA/cm2. On the other hand, perhaps due to the removal of the amorphous silicon layer on the light-receiving surface, or because of changes in cell thickness, the open-circuit voltage, which can be affected by carrier recombination losses, has been reduced from 0.75V to 0.74V, and the fill factor has also been from 0.832. Drop to 0.827. With the back contact structure, although the conversion efficiency of the battery unit is improved, a corresponding price is paid, that is, the structural symmetry of the light receiving surface and the back surface is lost. Since the structure of the light-receiving surface and the back surface of the Panasonic previous battery cell is symmetrical, there is an advantage that the warping phenomenon is less when the cell thickness is reduced. The company used this advantage to obtain a lot of research results on thin units with a thickness of only about 100 μm. If the thickness of the unit can be reduced, material costs can be reduced. In the back contact structure, the structure of the light receiving surface and the back surface is different from each other, so that it is generally unfavorable to reduce the thickness of the cell. In addition, the thickness of the unit that achieved 25.6% conversion efficiency is currently not disclosed. In related research in Japan, Sharp, like Panasonic, is also vigorously developing a structure that fuses heterojunctions and back contacts. In other countries, companies such as LG Electronics have published relevant technologies in the society. In contrast to Panasonic, Sharp applied the back contact structure to its products and began to devote itself to the development of fusion with heterojunctions, thereby rapidly improving the conversion efficiency at the level of research and development. This time, Panasonic, which is leading in the development and practical use of heterojunctions, is also beginning to merge into heterojunctions and back contacts. It is estimated that this will affect the research and development trend of crystalline silicon solar cells in the future. Wrench is a commonly used installation and removal tool. It is a hand tool that uses the principle of leverage to turn bolts, screws, nuts, and other threads to hold the openings or sleeves of bolts or nuts. Wrenches are usually made of structural steel made of carbon or alloy materials. Spanner Series,Super Wide Adjustable Wrench,Torque Wrench,Gear Wrench,Wheel Wrench Rugao Yaou Import & Export Trade Co., Ltd , https://www.ntyaoumachinery.com