Important Points When Choosing an Electricity Storage System

These are the key points to consider when selecting an electricity storage system. As these systems are continually used for extended periods of time, we recommend that you carry out a careful comparative assessment to choose the best electricity storage system for you.

1: Lifecycle Costs

Battery capacity after ten years can vary significantly due to its cycle count, even for the same initial battery capacity.

For an electricity storage system, lifecycle costs refer to total expenses (lifetime expenses) from purchase to disposal.
While customers tend to focus on initial costs, since storage batteries have their own product lifetime, it is important to consider lifecycle costs including product lifetime (cycle count and remaining battery capacity).

What is the “cycle count” estimate of storage battery life?

Cycle count is a figure indicating how many times a battery can be repeatedly charged and discharged, with one charge and one discharge together regarded as a single cycle.
The estimated life-span of a storage battery is indicated by the cycle count or a number of years.

The capacity of a storage battery gradually declines over time.

When the maximum cycle count (life-span) is reached, the capacity and performance of a storage battery declines significantly and the battery may be unable to ensure adequate backup time.
By choosing a high-quality, long-life electricity storage system, it is possible to reduce lifecycle costs and be reassured that the system can be used for a long time.

ELIIY Power’s battery cells

Even if ELIIY Power’s battery cells have achieved long service life, with 70% capacity retention* even after repeated use for 15 years of full-charging/discharging (approximately 17,000 times). You can feel secure about using them for a long time.

* Battery cell type: PD50S06
This is an estimated service hour of the battery cell at room temperature (25℃), charging current 48.5A (1C), 3 cycles/day (DOD=100%). The capacity retention of the battery cells may change depending on the usage condition of the energy storage system (e.g. frequency of charging/discharging, operating environment, etc.). The actual electrical capacity of the energy storage system may differ from the total electrical capacity of the battery cells built into the system because of the system usage condition.

2: Safety

Choose an electricity storage system that offers a high level of safety and is prepared for eventualities such as natural disasters and unexpected accidents.
Since electricity storage systems hold hundreds of times more energy than mobile phone batteries, improper handling incurs the risk of a serious accident such as fire.

Regular lithium-ion batteries monitor and control voltage and temperature in order to offer safety assurances through system control provided by a battery management unit (BMU). However, as there is a possibility of the battery producing smoke or fire when abnormalities occur in the electricity storage system or BMU due to secondary damage from a disaster such as an earthquake or fire, or from another unexpected accident, we recommend selecting a product equipped with battery cells that demonstrate high levels of safety.

Battery cells that achieve world-class safety

The battery cells used in ELIIY Power’s electricity storage systems achieve world-class safety and do not produce smoke or fire even if punctured with a nail, crushed or overcharged.
Moreover, the manufacturing of our battery cells is conducted at our domestic in-house plant at which all processes are automated, as part of our efforts to ensure quality and safety.

3. Temperature Characteristics

Our batteries are compatible with various usage environments thanks to a wide range of usable temperatures.
Electricity storage systems are easily impacted by the surrounding environment, such as temperature and humidity. At temperatures that fall outside manufacturer-recommended usable temperature ranges, the products cannot produce adequate performance.
Depending on the installation environment, there may be cases that invalidate guarantees or prevent installation altogether, and care should be taken when selecting a system.  

By choosing an electricity storage system with excellent temperature characteristics, it is possible to install a system outdoors in a cold region, or on the south-facing side of a home that heats up when exposed to direct sunlight, facilitating the effective utilization of space.

Excellent temperature characteristics

ELIIY Power’s battery cells feature a wide range of usable temperatures from -20°C to 60°C*.
As the batteries demonstrate stable performance across a wide range of temperatures from low to high temperatures, they can handle a wide range of usage environments.  

* Differs from the guaranteed operating temperature range of an electricity storage system.