The large cylindrical ternary battery represented by the 46 series is taking over the passenger car market and starting a new round of competition for mainstream technology routes. The large cylindrical battery mainly based on LiFePO4 material also launched a turbulent offensive in the household energy storage market. At present, some battery companies including some of China's top 10 home energy storage battery companies, CBAK and other battery companies have successively launched large cylindrical lithium iron phosphate batteries for the home energy storage market.
1. Large cylindrical LiFePO4 batteries are favored by the home energy storage market
Large cylindrical LiFePO4 batteries are favored by the home storage market. On the one hand, thanks to the optimization of all-tab technology, manufacturing process and material system, the advantages of large cylindrical LiFePO4 products in terms of cost, capacity, performance, cycle and safety are prominent. On the other hand, since 2021, energy costs and electricity prices in Europe have continued to rise, superimposed by the Russian-Ukrainian war and large-scale power outages overseas. Especially in recent years, the frequent occurrence of extreme weather has made energy supply more difficult.
Residential electricity demand and electricity costs have increased significantly, and the home energy storage market has exploded beyond expectations. Some institutions predict that the world will usher in a new stage of home energy storage explosion in 2022. By 2025, the global home energy storage market will reach 60.3GWh, with a compound annual growth rate of 55.9%. The capacity of household energy storage system is iterated from 3kWh~5kWh to 5kWh~20kWh, and the upgrade of energy storage system also puts forward requirements on battery capacity, cost, power and life.
Industry analysts pointed out that in the home energy storage market, the demand for capacity and portability is different, which in turn puts forward higher requirements for flexible series and parallel of cells, and the advantages of flexible grouping of cylindrical batteries are highlighted. Compared with the traditional small cylindrical battery, the size of the large cylindrical battery is increased, the capacity of the single battery is higher, and the series and parallel and structural parts are reduced after forming the PACK. Conducive to reducing costs, combined with market demand and technology iteration, large cylinders are becoming a trend.
2. Many companies deploy large cylindrical energy storage batteries
EVE has launched 40135 series of large cylindrical LiFePO4 batteries for the home storage market. A few days ago, GREAT POWER revealed that its 40135 large cylindrical lithium iron phosphate battery has received customer orders. The battery adopts no (full) tab structure, low temperature superconductivity of LiFePO4 and full cycle dynamic equalization technology. With the characteristics of super power, long battery life, and wide temperature range, this battery is suitable for portable energy storage, home energy storage, and electric light vehicles. Recently, HITHIUM also released a large cylindrical battery for household energy storage scenarios.
The product specifications cover 46800-46300, and the unit capacity ranges from 10Ah to 50Ah. It has strong flexibility and adaptability, and can meet the customized needs of various household energy storage application scenarios. A 46mm large cylindrical battery has been developed, which is greatly improved in cost, flexibility, safety, life and storage consistency compared with the traditional small cylindrical battery. In addition, companies including CBAK and Greenway are reducing costs by increasing the size of cylindrical cells to meet the needs of household energy storage battery application scenarios.
3. Characteristics and trends of large cylindrical LiFePO4 batteries
● There are many specifications of large cylinders, and several mainstream models have not yet been formed.
Unlike ternary large cylindrical batteries, which are mostly based on the 46 series, for the home energy storage market, the specifications and models of battery cells currently produced by various companies are different. For example, the large cylindrical cells of EVE and GREAT POWER are mainly 40135 models (40mm in diameter and 135mm in height), while HITHIUM is based on 46mm in diameter and covers 80mm~300mm in height. In addition, some companies produce large cylindrical cells for home storage with a layout ranging from 26mm to 60mm in diameter.
Industry analysts pointed out that the current home storage large cylindrical batteries are different in diameter and height. On the one hand, the product is in the early stage and has not yet formed a unified standard. On the other hand, it is also related to the characteristics of home storage products. At present, home energy storage products are still in the initial stage of development, and product specifications and models have not been standardized. At the same time, there are also many demand for customized battery cells in home energy storage. Many companies have launched customizable battery cell designs to adapt to the needs of products in different scenarios.
● All-tab (multi-tab) technology may be standard, optimized for lithium iron phosphate materials.
All-tab technology is an important link to achieve high power density. It uses the entire positive and negative current collectors as tabs, and connects the current collector with the battery case or battery cover plate over the entire area, which can greatly reduce the internal resistance and heat generation of the battery. So as to solve the heating problem of high energy density cells, and improve the peak power of charging and discharging.
At present, large cylindrical batteries for passenger vehicles generally adopt the multi-tab or full-tab method, which can effectively reduce the internal ohmic impedance of the battery, reduce the heat generation of the battery, and greatly improve the rate performance of continuous charging and discharging. At present, companies with this technology have also transplanted this technology to the large cylindrical LiFePO4 battery for the home storage market. In addition, in response to the impact of extreme weather on the performance and safety of the battery itself, companies that develop battery cells for energy storage have also adopted a variety of technological innovations to improve the performance of large cylindrical batteries.
● Aiming at the threshold of 5000 cycles of life, breaking through to higher goals.
Service life is a key indicator of energy storage batteries. According to the needs of household large cylindrical energy storage batteries, the 2000-cycle cycle life of traditional cylindrical batteries obviously cannot meet the needs. In terms of large-cylindrical process and material innovation, relevant companies have now aimed at 5,000 or more cycles of cycle life for large-cylindrical energy storage batteries. Before large cylinder batteries, 18650 batteries were popular, and there are many 18650 battery stores on the market. In order to realize that household energy storage battery products can meet the needs of 10 years or more of use.
As the most important performance requirement of energy storage batteries, safety is one of the factors that need to be considered in the production of large cylindrical batteries. The lithium iron phosphate material itself has relatively high safety, and the cylindrical battery can be designed with a high-strength steel shell, which is less affected by the expansion of the pole group, and has higher impact resistance and higher reliability. It is an important support for the safety of large cylindrical batteries.
As the most mature battery process route, cylindrical batteries have self-evident advantages in terms of manufacturing efficiency, customized production and matching. At present, many battery companies have begun to focus on the deployment of large cylindrical LiFePO4 batteries in response to the needs of home energy storage and portable energy storage application scenarios.