Currently in the field of household energy storage and charging, the mainstream batteries are lithium-ion batteries and lead-acid batteries. In the early stage of energy storage development, it was difficult to achieve large-scale applications due to the technology and cost of lithium-ion batteries. Currently, with the improvement of lithium-ion battery technology, the decrease in large-scale manufacturing costs, and the stimulation of policy guidance and other multiple factors, the application of lithium-ion batteries in the household sector has far surpassed that of lead-acid batteries. Of course, product attributes also need to match the characteristics of the market. In some markets with outstanding cost-effectiveness, there is also a strong demand for lead-acid batteries.
Lithium-ion batteries have the following characteristics compared to lead-acid batteries:
Lithium-ion batteries have higher energy density, 30WH/KG for lead-acid batteries and 110WH/KG for lithium-ion batteries.
Lithium-ion batteries have a longer cycle life, averaging 300-500 times for lead-acid batteries and over a thousand times for lithium-ion batteries.
Different nominal voltages: individual lead-acid batteries are 2.0V, individual lithium-ion batteries are around 3.6V, and lithium-ion batteries are easier to connect in series or parallel to form battery packs for different applications.
For the same capacity, lithium-ion batteries have smaller volume and weight. The volume of lithium-ion batteries is 30% smaller, and the weight is only one-third to one-fifth of lead-acid batteries.
The current application of lithium-ion batteries is safer, with a BMS managing all modules.
Currently, conventional household energy storage batteries have high-voltage batteries and low-voltage batteries. The parameters of the battery system are closely related to the battery selection and need to be considered from installation, electrical, safety, and environmental aspects.
Installation Parameters
Weight, length, width, height. The bearing capacity of the ground or wall and whether the installation conditions are met need to be considered based on different installation methods. The available installation space and whether the length, width, and height of the battery system will be limited in this space should also be considered.
Installation method. How to install it on-site, installation difficulty, such as floor-standing/wall-mounted installation.
Protection level. The highest level of waterproof and dustproof. A higher protection level means the battery can be used outdoors.
Electrical Parameters
Available energy. The maximum sustainable output energy of the system, which is related to the rated energy and system depth of discharge.
Operating voltage range. This voltage range needs to match the battery input voltage range of the inverter. Battery systems with voltages higher or lower than the inverter's battery voltage range will result in the inability to match the inverter.
Maximum continuous charge and discharge current. The maximum charge and discharge current supported by the battery system determines how long it takes for the battery to be fully charged. This current is limited by the maximum current output capability of the inverter's port.
Rated power. The rated power of the energy storage battery system, and the selected power should ideally support the inverter's full load charge and discharge power.
Types of battery cells. The mainstream battery cells are lithium iron phosphate (LFP) and lithium nickel cobalt manganese (NCM). Compared with NCM materials, LFP materials are more stable.
Warranty. The content, term, and scope of the battery warranty terms.
Operating temperature. The range of environmental temperature in which the energy storage battery can operate. The charging temperature range supported by the battery is 0-50°C, and the discharging temperature range is -20-50°C.
Humidity, altitude. The maximum humidity range and altitude range that the battery system can withstand. These parameters need to be paid attention to in some damp or high-altitude areas.
