Although large automakers are skeptical, the same 18650 units as the portable equipment market can reduce costs, so there are many companies that recommend cylindrical units. In addition, the BAK battery indicates that the "cylinder type is the most ideal" (the company's CTO Mao Huanyu) is equipped with a shape that can be freely changed according to the requirements of the car manufacturer. The trend of electric motorcycles equipped with lithium-ion rechargeable batteries in the Chinese market is expanding, so the demand for cylindrical units with lower prices in the future is higher, and the possibility of increased sales is more likely to be 5) .
Note 5) BAK Battery indicates that China has about 80 million electric motorcycles with an annual demand of 20 million. The proportion of lithium-ion rechargeable batteries in annual sales is 1% in 2008, but will reach 3% in 2011.
Positive and negative materials are also diversified
Not only the shape of the unit, but also the types of materials such as the positive electrode material and the negative electrode material are not selected, and it seems to be increasingly diversified. At present, the positive electrode material uses lithium manganate (LiMn 2 O 4 ), ternary (Li(Ni-Mn-Co)O 2 ), lithium iron phosphate (LiFePO 4 ), and NCA (Li(Ni-Co-Al)O. 2 ) Class. In addition to the carbon material, the possibility of using lithium titanate (Li 4 Ti 5 O 12 , LTO) is also increasing.
BMW AG at the AABC, with the title "Development of Hybrid Vehicles at BMW and their Energy-Storage Solutions", published a comparative study of the positive and negative materials of lithium-ion rechargeable batteries for HEV. (Table 2). Although it is not stated which material BMW will use, it is considered to be very interested in using LTO as a negative electrode material.
For example, with LTO, although the energy density is low, the charge and discharge cycle life is long, so the amount of power available during the life of the product is larger than that of the carbon material. Moreover, regarding the safety, it is concluded that the selection of the positive electrode material is required when using the carbon material, and the safety is superior when the LTO is used. However, LTO is more expensive than materials using carbon materials.
Toyota uses NCA class
From the perspective of safety, BMW believes that NCA-based cathode materials are difficult to use in automotive applications. Toyota used it on the PHEV. The company introduced the details of the lithium-ion rechargeable battery equipped with the Prius plug-in hybrid car under the title "Development of Plug-in Hybrid Vehicle".
The unit is a 5Ah square unit made by Primearth EV Energy (formerly Panasonic Electric Vehicle Energy) with a voltage of 3.6V. In terms of energy density, the unit weight is 73 Wh/kg and the unit volume is 103 Wh/L. The external dimensions of the battery unit are 110 mm x 14 mm x 112 mm and weigh 245 g. It is estimated that the unit is developed for HEV, and Toyota is likely to adopt the new HEV that will be launched in the future.
It is said that such a battery is provided with a coating on a current collector aluminum foil of a positive electrode of a battery cell, and an NCA-based electrode material is coated thereon (Fig. 4). The negative electrode material is made of a carbon material, but it is not disclosed as graphite or amorphous. The diaphragm is composed of polypropylene (PP) and polyethylene (PE).
In order to eliminate the safety hazard of the NCA-based material, a ceramic layer "HRL (heat resistance layer)" having high heat resistance is formed on the negative electrode. This technology has been applied to Panasonic cylindrical units. By optimizing the coating method of the electrode material, Toyota realized that the internal resistance of the battery cell hardly increased after driving 200,000 miles (about 320,000 km), and showed strong confidence in the charge and discharge cycle life.
Prototype 250Wh/kg unit
Although AABC 2010 is based on the types of materials that have been put into practical use, Envia Systems of the United States has also lectured on the lithium-ion rechargeable battery of solid solution cathode materials that have attracted much attention as a new generation of cathode materials. Note 6) . The solid solution-based positive electrode material Li 2 MnO 3 -LiMO 2 (M: metals such as Ni, Mn, and Co) is characterized by having a high capacity of more than 280 mAh/g, which is about twice as large as that of the original positive electrode material (Fig. 5).
Note 6) Envia is a company established in July 2007 and is currently developing lithium-ion rechargeable batteries using Argonne National Laboratory's solid solution cathode material technology.
 |
| Figure 4: Toyota uses NCA-based cathode materials At the end of 2009, Toyota adopted a square-type lithium-ion rechargeable battery (a) on the Prius plug-in hybrid. The positive electrode material is characterized by the NCA system (b). |
This article refers to the address: http://
Figure 5: Solid solution cathode material can reach a capacity of more than 280mAh / g
Envia has developed a lithium-ion rechargeable battery (a) using a high-capacity solid solution positive electrode material of 280 mAh/g or more. A unit with a current capacity of 20 Ah was prototyped and output (b) at a high discharge rate of 3C.
The cost of the material can be reduced based on Mn. In Japan, Nissan Motor Co., Ltd. is also developing. However, the potential of this material is higher than that of lithium, reaching 4.6V. Therefore, in addition to developing an electrolyte that does not decompose under high voltage, Envia also adopts measures such as surface modification of the positive electrode material.
The company has produced a 20Ah laminated unit for EV, achieving an energy density of 250Wh/kg. The unit has an outer dimension of 175 mm x 95 mm x 8 mm. The charging voltage is 4.5V, the average voltage is 3.5V, and the termination voltage is 2.0V. Even if 3C (20 points) discharge is performed, the capacity will not decrease.
Envia is currently applying for more than 15 patents and plans to use these patents to conduct business. (Full text reporter: Shou Jihao)
â– Japanese original text: the battery life of the car
Fiber Optic Distribution Box,Fiber Optic Breakout Box,Fibre Optic Breakout Box,Fibre Break Out Box
Cixi Dani Plastic Products Co.,Ltd , https://www.cxdani.com