This year’s Battery Japan, a major annual trade show on rechargeable battery technologies, showed the continuing market interest in the lithium-ion battery (LIB) for the electric vehicle (EV). Large discussion forums were held during Battery Japan 2018 to examine the following topics: supply and prices of upstream materials; the future development of the lithium iron phosphate (FLP) batteries; and the progress on the volume production of solid-state batteries. The entire trade show was held from 28 February to 2 March in Tokyo.
The presentation made by China’s BYD during Battery Japan asserted that the rapid growth of the EV market will drive demand for key materials used in ternary LIBs. The supply of these materials will begin to fall behind the growing demand by 2020, and the shortage problem will be especially acute for cobalt. BYD added that the only effective way to alleviate the tight supply situation for the key materials would be to accelerate the market entry of FLP batteries. Also, BYD in its presentation advocated for a progressive phase-out of earlier types of batteries because this can help increase the reuse of these batteries for other applications. With respect to government policies, BYD contended that energy density should not have so much weight in the criteria for subsidy eligibility.
CATL’s presentation forecast that the development of battery materials will be divided into two levels after the 811 type reaches maturity. On the high-density level, manufacturers will be pursuing the solid-state battery technologies. On the low-density level, manufacturers will experiment with combinations of ternary materials and silicon alloys. The two branching paths of development are expected to address the different energy density demands in the market over the next five years.
The discussions on the development of solid-state batteries mainly pertained to finding viable production technologies and establishing the necessary conditions for the production process. During the trade show, Toray presented its processing technology for the manufacturing of solid-state battery cells. Toray’s solution specifically tackles the problem of swelling and smoke when temperature is at 100∘Celsius or above. The cathode material is a NCA/LGPS film that is about 50μm thick, while the solid electrolyte is composed of Li10GeP2S12 that is about 450μm thick. Toray has devised a sophisticated adhesive technique that can effectively paste anode and electrolyte together. The adhesive technique has the potential to provide a giant step forward in the replacement of traditional LIBs by solid-state batteries.
FDK’s thin solid-state battery that was on display at the trade show uses Li2CoP2O7 as the cathode material and operates at 5V. Just half of this battery has a capacity of 220mAh/g. For the same thickness, FDK’s solid-state design offer longer battery life and higher energy density compared with conventional LIBs using LCO or LMO as the cathode material. Maxwell, an established mainstream battery supplier, is also entering the race to develop solid-state products. According to Maxwell’s roadmap, the solid-state design will initially enter the small-size battery market and reach the mass production stage in 2020. Then, solid-state batteries will become available for the energy storage application by 2022. EV-related products will finally take off sometimes in 2025.
(The content of this article is based reporting by Duff Lu, senior research manager of EnergyTrend.)