Integrated and Split Energy Storage Systems Explained and Compared

Why Household Energy Storage Is Gaining Momentum

With the acceleration of global energy transformation, energy storage technology has become one of the core key technologies for sustainable energy development. In the past two years, the household energy storage industry has been very popular and is in a stage of rapid development. The demand for energy storage is growing rapidly, and the world is entering a new stage of household energy storage explosion.

What Is a Household Energy Storage System?

Household energy storage refers to an energy storage system used for home, commercial or industrial purposes, which uses distributed photovoltaic equipment to generate electricity and manage and store the electricity to improve the efficiency of self-generated electricity and reduce economic costs.

Main Components of a Home Energy Storage System

Household energy storage systems usually consist of batteries, inverters, photovoltaic modules, etc.

Batteries can store electrical energy and release it when needed.

Inverters are responsible for converting DC power into AC power for supply to household electrical appliances.

Photovoltaic modules are devices that convert solar energy into electrical energy, which can provide renewable energy for energy storage systems.

Additional System Components

In addition, household energy storage systems also include monitoring systems, safety systems, and control systems to ensure the safe and reliable operation of energy storage systems. The integration of these systems allows home, commercial or industrial users to better manage their energy consumption and access stored energy whenever needed, so as to better control their electricity costs and carbon footprint.

Two Main Types of Household Energy Storage Systems

(1). All-in-one Energy Storage System:

The household photovoltaic energy storage inverter is an integrated system that places the photovoltaic inverter, battery and controller inside, and has been equipped with accessories such as brackets and cables, and can be directly installed and used. The touch screen can conveniently and intuitively display the working status, modify parameters and multiple working modes, which is convenient to use.

Key Features and Operation Modes

Generally, there are three working modes: solar priority mode, AC (mains power) priority mode, and SE priority mode (peak power mode); this energy storage system can adjust the number of batteries and inverters as needed, and has high flexibility.

Advantages and Limitations of All-in-One

Advantages:

1. High integration, easy to install and maintain;

2. Beautiful appearance, small space occupation;

3. Save procurement costs, relatively cheap price;

4. Highly integrated, effectively reducing soft costs.

Disadvantages:

1. Insufficient expansion capacity, limited storage capacity;

2. Poor heat dissipation performance, not suitable for long-term high-load operation;

3. The operating system and storage space cannot be upgraded;

4. Low adjustability and poor flexibility.

Efficiency of DC-Coupled Systems

The integrated photovoltaic and storage devices mostly adopt DC coupling, which has higher overall efficiency. Users have less load during the day and more load at night, so it is better to use DC coupling. The photovoltaic modules store electricity in the battery through the controller, and the efficiency can reach more than 95%.

Typical products: Tesla POWERWALL

(2). Split-Type Energy Storage System (Inverter + Battery)

The household split unit battery and inverter are installed separately. Users can match household energy storage inverters according to their own needs. In addition, they can match switching power supplies or inverters as backup power supplies.

Key Types of Split Systems

Generally, there are four types: hybrid household photovoltaic + energy storage system, coupled household photovoltaic + energy storage system, off-grid household photovoltaic + energy storage system, and photovoltaic energy storage energy management system.

Advantages and Limitations of Split Energy Storage

Advantages:

1. Large storage capacity and strong scalability;

2. Good heat dissipation performance, suitable for long-term high-load operation;

3. Upgradable operating system and storage space;

4. Good flexibility, can meet some personalized needs.

Disadvantages:

1. Installation and maintenance are more cumbersome;

2. The appearance is relatively bulky and occupies a large space;

3. The price is relatively high.

Efficiency of AC-Coupled Systems

AC coupling mode is usually adopted to facilitate connection with the photovoltaic inverter of the original photovoltaic system.

The user has more load during the day and less at night, so it is better to use AC coupling. The photovoltaic components directly supply power to the load through the grid-connected inverter, and the efficiency can reach more than 96%. If the load is less during the day and more at night, the photovoltaic must first be converted into AC power through the inverter, and then converted into DC power through the bidirectional converter. The efficiency of AC coupling will drop to about 90%.

Typical product: BYD B-BOX

How to Choose Between All-in-One and Split Energy Storage

1. The existing market of installed household photovoltaics;

2. The simple installation and maintenance, beautiful appearance, and relatively low price make it more suitable for ordinary household users.

When to Choose All-in-One Systems

1. The existing market of installed household photovoltaics;

2. The simple installation and maintenance, beautiful appearance, and relatively low price make it more suitable for ordinary household users.

When to Choose Split-Type Systems

1. The incremental market of installing household photovoltaics and energy storage systems;

2. The advantages of large storage capacity, strong scalability, good heat dissipation performance, upgradeable operating system and storage space make it have certain advantages in the high-end user and professional user market.