What is an energy storage battery? What is a power battery? Can the battery life reach ten years?
Energy storage batteries and power batteries are important technologies in the field of energy storage and electric transportation today. Essentially, both types of batteries belong to energy storage batteries and there is not much difference in their technical routes.
What are the differences between these two types of batteries? Can it be mixed? This article provides an introduction and analysis to help everyone better understand the specific differences between the two types of batteries.
What is an energy storage battery?
Energy storage battery, as the name suggests, is a battery system used for storing electrical energy. They can convert electrical energy into chemical energy, store charges in batteries, and then release them when needed. Energy storage batteries are typically designed for long-term energy storage and charging/discharging, playing an important role in power grid scheduling, peak load reduction, and energy management. The key characteristics of energy storage batteries are high capacity, long cycle life, and stable performance.
What is a power battery?
Power batteries are specifically designed to provide the power required for electric vehicles. They need to have high energy density and high power output to meet the requirements of electric vehicles for acceleration performance and driving range. The design focus of power batteries is to improve the charging speed, discharging 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.
Further explore the main differences between energy storage batteries and power batteries, mainly reflected in the following points.
01 Application Scenarios
Energy storage batteries are widely used in power grid energy storage, household 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-term energy storage. Due to the fact that the vast majority of energy storage devices do not require movement, lithium energy storage batteries do not have direct requirements for energy density; Different energy storage scenarios have different requirements for power density; In terms of battery materials, attention should be paid to factors such as expansion rate, energy density, and uniformity of electrode material properties, in order to pursue a long lifespan and low cost for 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 focus more on power density and short-term high-power output to meet the needs of electric vehicles for fast acceleration and long mileage. Compared to energy storage batteries, power batteries have higher requirements for energy density and power density. Furthermore, due to the limitations of vehicle size, weight, and acceleration during startup, power batteries have higher performance requirements than ordinary energy storage batteries.
02 System composition
The power battery PACK is basically composed 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 determined by the battery cells, structural components BMS、 The comprehensive cost composition includes box body, auxiliary materials, manufacturing expenses, etc., with battery cells accounting for about 80% of the cost. Pack (including structural components BMS、 The cost of the box, accessories, manufacturing expenses, etc. accounts for about 20% of the total cost of the battery pack.
The energy storage battery system mainly consists of battery packs, battery management systems (BMS), energy management systems (EMS), energy storage converters (PCS), and other electrical equipment. In the cost composition of energy storage systems, batteries are the most important component, accounting for 60% of the cost; Next is energy storage inverters, accounting for 20%, EMS (Energy Management System) costs account for 10%, BMS (Battery Management System) costs account for 5%, and others account for 5%.
03 Battery BMS
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 consistent, and directly affects whether the battery pack can provide safe and reliable 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 located on a high-speed moving electric vehicle, which has higher requirements for the power response speed and power characteristics of the battery, SOC estimation accuracy, and the number of state parameter calculations. The relevant adjustment functions also need to be implemented through BMS.
04 cycle times
Power batteries and energy storage batteries have different requirements for their service life. Energy storage batteries usually need to have a longer cycle life, able to withstand thousands of charge and discharge cycles without significantly reducing performance.
Taking electric vehicles as an example, the theoretical lifespan of a ternary lithium iron phosphate battery pack is 1200 cycles. Based on a usage frequency of fully charging and discharging once every three days, the lifespan of a ternary lithium battery can reach ten years.
Compared to power batteries, energy storage batteries charge and discharge more frequently, and have higher requirements for cycle life under the same 10-year lifespan. If energy storage power stations and household energy storage batteries charge and discharge once a day, the cycle life of energy storage lithium batteries should be greater than 3500 times. If the charging and discharging frequency is increased, the cycle life requirement is usually required to reach 5000 times or more.
05 Battery Cost
Cost is also one of the differences between the two. The cost of energy storage batteries is relatively low because they use more mature battery technology and have relatively simple application conditions, which can achieve economic benefits in large-scale applications.
In contrast, the cost of power batteries is higher, mainly due to the requirements for high energy density and high power output, as well as the need for long battery life and high safety compatibility.
Can energy storage batteries and power batteries be mixed?
Energy storage batteries cannot be used in electric vehicles, as there are different rates, internal resistances, capacities, and voltages between the two. Energy storage batteries generally have higher energy density, but lower power density. For example, if discharged above 0.5C, the temperature will be too high, so energy storage batteries cannot be used as power lithium batteries.
However, power lithium batteries can be used as energy storage batteries, and it is necessary to understand the design and configuration of the control system for the discharge size of lithium batteries. However, both power batteries and power control systems have high cost factors, which can 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 capability of around 5C, which is widely used in frequency regulation. Some companies will reuse retired power batteries as energy storage batteries for household and mobile energy storage applications.
