Compared to lead-acid batteries, lithium batteries have much more diverse characteristics. Therefore, the intention of this article is not to teach you how to choose or plan a battery system, but to introduce some key factors that determine battery selection. Mastering these common sense can also help you prepare in advance to discuss plans with suppliers, especially when you have to weigh and choose between many plans.
Charging and discharging characteristics of batteries
The charging and discharging rates of batteries vary, which can help distinguish between energy batteries and power batteries. The standard for UPS and energy storage battery configuration is to discharge at full load, but in practical applications, they often do not reach full load.
Balanced function
Balancing function is a standardized way to achieve battery goals (such as yuan/watt hour, watt hour/kilogram, and watt hour/liter), which can more accurately compare the differences between power batteries and energy batteries for the same application. The main variable that affects the balancing function in typical APCUPS scenarios is discharge power. The discharge power pointer refers to the amount of electricity extracted from the battery system at a set discharge rate for a given application. The faster the discharge rate, the lower the discharge power, especially for energy batteries. The charging and discharging power includes both charging power and discharging power, but for typical APCUPS applications where the charging speed is slow but the discharging speed is fast, we only need to focus on the discharging power.
The balancing function of lead-acid batteries differs significantly in energy and power utilization. Lead acid batteries release nearly 100% of their energy at a 20 hour discharge rate, but only 33% at a 5-minute discharge rate. If the cost of lead-acid batteries at 100% discharge power is 700 yuan/kWh, then at 33% discharge power, the average cost is 700 yuan/kWh/33% power=2121 yuan/kWh. Please note that other objectives such as the scale and composition of the battery system are also important. The same applies to lithium-ion energy batteries and power battery units and systems. Compared with lithium-ion power batteries used at similar rates in the same application, lithium-ion energy batteries used for power applications have lower discharge power.
Many important application constraints can affect the planning of battery systems, including scale, shape, cooling, and power. Due to these external planning constraints, companies are unable to make intuitive and accurate judgments when selecting battery systems.
Sites constrained by space may not be able to utilize larger scale batteries, thus necessitating the selection of higher priced battery systems. This is a challenge that many small venues face when selecting batteries, and it is also a category that inspires innovation and the development of disruptive technologies.
When the application scenario of the battery requires sealing and is in a high-temperature environment, the working temperature will impose greater constraints on the battery. These challenges may lead to a trade-off in battery selection requirements, such as choosing higher power power batteries for energy applications. Due to the higher charging and discharging power of power batteries, they generate less heat.