What is the difference between power lithium batteries and energy storage lithium batteries?

What is the difference between power lithium batteries and energy storage lithium batteries ?

From the perspective of application scenarios, power lithium batteries are mainly used in electric vehicles, electric bicycles and other power tools, while energy storage lithium batteries are mainly used in peak regulation and frequency regulation power auxiliary services, renewable energy and other fields. Grid connections and microgrids.

Due to different application scenarios, the performance requirements for batteries are also different. First of all, as a mobile power source, power lithium batteries have the highest requirements for volume (and mass) energy density under the premise of safety, in order to achieve longer battery life. At the same time, users also hope that electric vehicles can be safely and quickly charged, so power lithium batteries have high requirements for energy density and power density, but for safety reasons, the charge and discharge capacity is generally about 1C.

Most energy storage devices do not need to be moved, so energy storage lithium batteries have no direct requirements for energy density. For power density, different energy storage scenarios have different requirements.

Chen Yongchong, head of the energy storage technology research group of the Institute of Electrical Engineering of the Chinese Academy of Sciences, once pointed out that for power peak regulation, off-grid photovoltaic energy storage or user-side peak-valley energy storage scenarios, it is generally necessary to continuously charge and discharge the energy storage battery for more than two hours. , so it is suitable to use a capacity battery with a charge-discharge rate of ≤0.5C; for power frequency regulation in energy storage scenarios or smoothing the fluctuation of renewable energy, energy storage batteries need to be quickly charged and discharged within a few seconds to a few minutes, so it is suitable for ≥ The application of 2C power battery; in some application scenarios that need to undertake both frequency regulation and peak regulation, energy battery is more suitable. Of course, in this scenario, power batteries can also be used in conjunction with capacity batteries.

Secondly, compared with the power lithium battery, the energy storage lithium battery has higher requirements on the calendar service life. The lifespan of new energy vehicles is generally 5-8 years, while the lifespan of energy storage projects is generally expected to be greater than 10 years. The cycle life of power lithium batteries is 1000-2000 times, while the cycle life of energy storage lithium batteries is generally required to be greater than 3500 times.