Research and development progress of power battery technology in China

With the strong support of the Ministry of Science and Technology “863” plan and the Ministry of Industry and Information Technology’s new energy vehicle innovation project and other major special projects, since the “Tenth Five-Year Plan”, China has invested more than 800 million yuan in technology research and development funds. China’s power battery technology and industrialization level have been greatly improved, power battery shipments have grown rapidly, and a number of power battery companies with international competitiveness have emerged. At present, China has cultivated internationally well-known power battery companies such as CATL and BYD. There are 140 power battery companies in China, and the number is far beyond the level of other countries. With the strong support of the three five-year plans, the choice of material systems for power batteries is diversified. Under the premise of improving safety, it is an inevitable trend to seek a substantial increase in the specific energy of power batteries.

Development of power battery technology research and development

In the field of high-power power batteries for hybrid vehicles, the positive electrode adopts a mixed material of spinel lithium manganate and nickel cobalt manganese ternary material, and the negative electrode adopts artificial graphite material. The 6A·h lithium-ion power battery developed has a specific energy of 81W·h/kg and can be charged and discharged at 30C. The input/output specific power is greater than 4000W/kg under 50% SOC conditions, the cycle life is more than 5000 times (70% remaining capacity), the charge and discharge performance is superior under the low temperature condition of -20°C, and the charge and discharge capacity is greater than 83%.

In the field of power batteries for pure electric drive vehicles (including two types of energy type and energy-power type), the main technological progress is as follows:

The positive electrode adopts high-voltage lithium-rich layered lithium manganese oxide and nickel-cobalt-manganese ternary material mixed material, and the negative electrode adopts artificial graphite material. The developed 25A·h energy battery has a specific energy of 159.6W·h/kg, a specific power of 1101W/kg, and a capacity retention rate of 91% after 800 cycles of normal temperature cycling; the developed 25A·h energy-power balanced battery has a specific energy of 153.3W·h/kg, a specific power of 1498W/kg, and a capacity retention rate of 93% when it is cycled for 770 weeks at room temperature.

The positive electrode adopts lithium iron phosphate material, and the negative electrode adopts a mixed material of natural graphite and hard carbon. The developed 50A·h energy battery has a specific energy of 136.6W·h/kg, a specific power of 1101W/kg, and a capacity retention rate of 91% at room temperature for 800 cycles; the 20A·h energy-power balanced battery developed has a specific energy of 106.5W·h/kg and a specific power of 1119W/kg.

The positive electrode adopts a mixed material of spinel lithium manganese oxide and nickel cobalt manganese ternary material, and the negative electrode adopts artificial graphite material. The specific energy of the developed 25A·h flexible packaging energy battery reached 162W·h/kg; the specific energy of the developed 35A·h energy-power balanced battery reached 135w·h/kg.

The positive electrode adopts nickel-cobalt-manganese ternary materials, and the negative electrode adopts materials such as natural graphite/artificial graphite/mesocarbon microspheres. The specific energy of the developed power battery of 10A·h, 1A·h, 20A·h, 28A·h, 30A·h, 45A·h reaches 180W·h/kg, and the specific energy of the developed 2.6A·h18650 cylindrical battery reaches 200w·h/kg. Figure 1 shows China’s power battery technology system.