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

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

Batteries are used to store electricity. In terms of application, they are all energy storage batteries. Therefore, it can be said that all lithium batteries are energy storage batteries. Later, in order to distinguish applications, it is divided into consumer batteries, power batteries and energy storage batteries according to the scene. three. Consumer applications are mobile phones, notebook computers, digital cameras and other consumer products, power applications are electric vehicles, and energy storage applications are energy storage power stations.

The power battery is actually an energy storage battery, which is mainly used in electric vehicles. Due to the limitations of vehicle size and weight, as well as the requirements for starting and acceleration, power batteries have higher performance requirements than ordinary energy storage batteries, such as higher energy density. The higher the better, the faster the charging speed of the battery and the larger the discharge current, but the requirements for ordinary energy storage batteries are not so high. According to the standard, the capacity of the power battery is lower than 80% and can no longer be used in new energy vehicles, but it can also be used in the energy storage system with a little modification.

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.

It is used for power peak regulation, off-grid photovoltaic energy storage or user-side peak-valley energy storage scenarios. Under normal circumstances, the energy storage battery needs to be continuously charged or discharged for more than two hours. Therefore, a capacity type with a charge-discharge rate of ≤0.5C is suitable. Battery; used 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, suitable for applications ≥ 2C power batteries; and some require frequency modulation at the same time The energy-based battery is more suitable for peak-shaving application scenarios. Of course, both power and capacity batteries can also be used in this scenario.

Compared with power lithium batteries, energy storage lithium batteries have higher requirements for 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.

In terms of cost, power lithium batteries face competition with traditional fuel power sources, while energy storage lithium batteries need to face the cost competition of traditional peak regulation and frequency regulation technologies. In addition, the scale of energy storage power stations is basically at the megawatt level or even more than 100 megawatts, so the cost of energy storage lithium batteries is lower than that of power lithium batteries, and the safety requirements are also higher.

There are some differences between power lithium batteries and energy storage lithium batteries, but from the perspective of batteries, they are all the same. Both lithium iron phosphate batteries and ternary lithium batteries can be used. The main difference lies in the BMS battery management system. The power response speed and power characteristics of the battery, SOC estimation accuracy, charge and discharge characteristics, etc., can all be implemented on the BMS.