There are many aspects to Li-ion battery safety throughout its design processes, including safe battery structure, safe raw materials, protective functions and safety certifications. When interviewed by China Electronics News, Mr Su Jinran, deputy chief engineer of Tianjin Lishen Battery Co Ltd, said that product safety began in product design, therefore selecting the right electrode materials, separators and electrolytes are the first priority for safe battery design. For battery anode materials, ternary materials, manganese lithium and lithium iron phosphate, which have been widely used in battery design and yielded satisfactory performance, are more secure than traditional lithium cobaltate and nickel lithium.
Su said that at present, the R&D and manufacturing of anode, cathode and electrolyte materials have established sufficient scales in China, basically capable of satisfying the design and manufacturing requirements of Li-ion batteries. Furthermore, the research on some safe coating materials has started to be commercialized, providing a new aspect for improving Li-ion battery safety, but China still needs to invest more and follow up on R&D and applications in this area.
An executive from the mobile energy business of Sanyo Electric Co., Ltd in China commented that when it comes to safety of Li-ion battery, all parts and materials used for making the battery play important roles. They are therefore trying to put together parts and materials to ensure its safety as a whole. Furthermore, in order to utilize parts and materials, it is important to employ advanced industrial production technologies and quality control technologies when thinking about safety improvement. “To further ensure Li-ion battery safety, we need to jointly consider batteries and the electronic equipment that use them. Meanwhile, the issue of battery safety has to be addressed by electronic equipment manufacturers and battery manufacturers together.” said the executive.
Innovation-based standard setting
Due to the complexity in Li-ion battery safety mechanism, especially the impact on safety after re-using the batteries, the process of understanding Li-ion battery safety and setting its standards should be gradual and progressive. And the development and application of external control techniques should also be considered. Su suggested that as setting Li-ion battery safety standards is a highly technical job, both standard setting professionals from battery standardisation bodies and technical specialists from the battery industry, users and electronic control areas should participate in the process, including experimental verification works.
Senior engineer from China Electronics Standardization Institute, Mr Sun Chuanhao, said that Li-ion batteries currently could be divided into energy types and power types. As these two products have differences in materials and design structures, their testing methods and requirements are dissimilar, even under the same safety conditions. The so-called portable batteries belong to the energy type, including Li-ion batteries used in mobile phones, laptops, digital cameras and video cameras, while the power type battery is for power tools, electric bikes and electric vehicles. Sun suggested authorities should introduce separate Li-ion battery safety standards for these two distinctive types.
Many industry experts agreed that standard setting of Li-ion battery in China should be built on the foundation of independent innovation, but also need to learn and refer to international standards such as IEC, IEEE and UL.
Li-ion battery for vehicle use
Because of its light weight and high energy density, Li-ion battery’s application areas are expanding in China, and it is hoping that Li-ion technology could be heavily used in hybrid vehicles and electric vehicles, which could further increase Li-ion battery’s market penetration. As a result, developing Li-ion batteries for vehicle use has become a focus for many Chinese Li-ion battery manufacturers. An analyst from China Academy of Sciences, Mr Huang Xuejie, pointed out that although China is now the second largest Li-ion manufacturing country only behind Japan, it is not yet a strong country in this field. Many small-size batteries in China are still produced manually, resulting in varied product quality and fierce price competition. Commercialisation of power type batteries is till at an early stage in China, and there is still a vacuum for Li-ion batteries which could last 15 years on hybrid electric cars, as well as their key materials and technologies.
As there are high technical barriers for producing high end products such as vehicle-use Li-ion batteries, experts are calling for the cooperation between R&D, engineering technologies and management specialists. And in order to improve the technical level of China’s battery industry, the government should also give assistance and establish expertise spreading mechanism for the industry.