Energy storage batteries and power batteries are important technologies in today's energy storage and electric transportation fields. Essentially, both batteries are energy storage batteries, and there is not much difference in their technical routes. So what is the difference between these two batteries? Can they be mixed? This article will give you an introduction and analysis so that you can better understand the specific differences between the two batteries.
What is an energy storage battery?
Energy storage batteries, as the name suggests, are battery systems used to store electrical energy. They convert electrical energy into chemical energy, storing the charge in the battery and then releasing it when needed. Energy storage batteries are usually designed for long-term energy storage and charging and discharging, such as playing an important role in grid dispatch, peak load reduction and power management. The key features of energy storage batteries are high capacity, long cycle life and stable performance.
What is a power battery?
Power batteries are specifically used to provide the power required by electric vehicles. They need to have high energy density and high power output to meet the acceleration performance and driving range requirements of electric vehicles. The design focus of power batteries is to improve the charging speed, discharge speed and cycle life of the battery. At the same time, safety is also an important aspect of power batteries to ensure reliable operation under various conditions.
Let’s further discuss the main differences between energy storage batteries and power batteries, which are mainly reflected in the following points.
Energy storage batteries are widely used in grid energy storage, home energy storage, industrial and commercial energy storage, communication base stations and other fields. The design requirements of energy storage batteries are mainly optimized for energy density and long-term storage to meet the demand for large-capacity and long-lasting energy storage. need. Since most energy storage devices of energy storage batteries do not need to be moved, energy storage lithium batteries have no direct requirements for energy density; different energy storage scenarios have different requirements for power density; in terms of battery materials, pay attention to expansion rate and energy density , electrode material performance uniformity, etc., in order to pursue the long life and low cost of the entire energy storage device.
Power batteries are used in new energy passenger vehicles, commercial vehicles, special vehicles, engineering machinery and equipment, ships, etc. Power batteries pay more attention to power density and short-term high power output to meet the needs of electric vehicles for rapid acceleration and long mileage. Compared with energy storage batteries, power batteries have higher requirements for energy density and power density. Furthermore, since the power battery is limited by the size and weight of the car and the acceleration during startup, the power battery has higher performance requirements than ordinary energy storage batteries.
Power battery PACK basically consists of the following five systems: battery module, battery management system, thermal management system, electrical system and structural system. The cost of a power battery system is composed of comprehensive costs such as battery cells, structural parts, BMS, boxes, auxiliary materials, and manufacturing costs. Batteries account for about 80% of the cost. Pack (including structural parts, BMS, boxes, auxiliary materials, manufacturing costs, etc.) ) cost accounts for about 20% of the entire battery pack cost.
The energy storage battery system mainly consists of battery pack, battery management system (BMS), energy management system (EMS), energy storage converter (PCS) and other electrical equipment. In the cost structure of the energy storage system, the battery is the most important component of the energy storage system, accounting for 60% of the cost; followed by the energy storage inverter, accounting for 20%, and EMS (energy management system) cost accounting for 10%. BMS (battery management system) cost accounts for 5%, and others are 5%.
As the core component of the battery system, BMS (battery management system) determines whether the various components and functions of the battery pack can be coordinated, and is directly related to whether the battery pack can safely and reliably provide power output for electric vehicles. The energy storage battery management system is similar to the power battery management system, but the power battery system is on a high-speed moving electric vehicle and has higher requirements for the battery's power response speed and power characteristics, SOC estimation accuracy, and the number of state parameter calculations. Relevant adjustment functions also need to be implemented through BMS.
04.Number of cycles
Power batteries and energy storage batteries have different requirements for service life. Energy storage batteries usually need to have a longer cycle life and be able to withstand thousands of charge and discharge cycles without significantly reducing performance.
Taking electric vehicles as an example, the theoretical life of the ternary lithium iron phosphate battery pack is 1,200 times. Based on the frequency of full charge and discharge every three days, the life of the ternary lithium battery reaches ten years.
Compared with power batteries, energy storage batteries are charged and discharged more frequently. Under the premise of the same 10-year life, they have higher requirements for cycle life. If energy storage power stations and household energy storage are charged and discharged once a day, the energy storage lithium battery will The cycle life requirement can be greater than 3,500 times. If the charge and discharge frequency is increased, the cycle life requirement is usually required to be more than 5,000 times.
Cost is also one of the differences between the two. The cost of energy storage batteries is relatively low because it uses more mature battery technology and its application conditions are relatively simple, which can achieve economic benefits in large-scale applications.
In comparison, the cost of power batteries is relatively high, mainly due to the requirements for high energy density and high power output, as well as the need for long life and high safety of batteries.
Can energy storage batteries and power batteries be mixed?
Energy storage batteries cannot be used in electric vehicles. There are different magnification rates, different internal resistances, different capacities, and different voltages between the two. Energy storage batteries generally have higher energy density, but lower power density. For example, if 280 exceeds 0.5C, the temperature will be too high, so the energy storage battery cannot be used as a power lithium battery.
The power lithium battery can be used as an energy storage battery. It is necessary to understand the design and configuration of the control system for the discharge size of the lithium battery. However, both the power battery and the power control system have high cost factors, which will lead to less than ideal economic benefits.
It is understood that energy storage lithium batteries also have power types, such as supporting a stable current discharge capacity of about 5C and are widely used in frequency modulation. Some companies will reuse retired power batteries as energy storage batteries for household storage and mobile energy storage.