A photovoltaic cell, also known as a solar cell, is the basic building block of a photovoltaic system. These cells are made of semiconducting materials such as silicon and, when exposed to sunlight, generate a flow of electrons (electricity). Multiple cells are combined to form a photovoltaic panel or module, and multiple modules are combined to form a photovoltaic array. Photovoltaic systems are often used to generate clean, renewable electricity for homes, businesses, and large-scale power plants.
1. Household energy storage system products
According to application scenarios, energy storage can be divided into user side (self-use, peak-valley price arbitrage), power generation side (grid connection of renewable energy, reduction of light and wind abandonment), power grid side (power peak regulation and frequency regulation), transmission and distribution side and auxiliary services (standby power supply of 5G base station).
Photovoltaic home energy storage system products include all-in-one and split.
1) All-in-one computer
A home-type photovoltaic energy storage inverter is an integrated system that puts a photovoltaic inverter, battery, and controller inside. It can display the working state conveniently and intuitively through the touch screen. Parameters can be modified, and various working modes can be used easily. Generally, there are three working modes: solar priority mode, AC (mains) priority mode, and SE (off-peak power mode) priority mode.
2) Split type (inverter + battery system)
The battery of the household split machine is installed separately from the inverter. Users can match the household energy storage inverter according to their own needs. In addition, a switching power supply or inverter can also be matched as a backup power supply. Generally, it includes four types: hybrid home PV + energy storage system, coupled home PV + energy storage system, off-grid home PV + energy storage system, and photovoltaic energy storage energy management system.
2. Technical route of home energy storage
The technical routes of energy storage batteries include lithium ion, lead battery, liquid flow battery, etc. Lithium iron phosphate lithium battery is more in line with the design requirements of energy storage batteries than lithium Terre battery due to their high safety and long cycle life characteristics. It is the mainstream development route of energy storage batteries. Tesla energy storage batteries gradually shift from the three-way route to the lithium-iron route. In addition, some companies, such as Ningde, Penang, etc., have been researching, developing, and testing sodium ion and ferromanganese lithium batteries. The technical route of future energy storage batteries is expected to be further improved.
3. Industry barriers to household energy storage
The core barrier of household energy storage lies in the adaptation and channel advantage of the energy storage inverter. As a small battery, household energy storage has low integrated core technology requirements. Its core competitiveness is a product design and market development (the key is market brand and channel construction).
1) Product design
For example, BMS in the energy storage system needs to be adapted to the energy storage inverter. The controller of the energy storage inverter communicates with the BMS through the CAN interface to obtain the status information of the battery pack, which can realize the protective charging and discharge of the battery. Ensure the safe operation of the battery.
2) Channel Construction
According to PV Magazine, brand reputation is the biggest factor consumers consider when buying energy storage batteries. Consumers rarely know the source of the cells and components used, and the certification cycle of overseas channels is complex and long, so the channel construction and maintenance of energy storage manufacturers, downstream integrators, and installers is particularly important.
4. Business model of home energy storage
Sales mode includes direct selling and distribution, brand and channel building advantage.
The sales models of the three types of players in the household energy storage industry chain are as follows:
1) Cell/energy storage inverter supplier
Divided into To C and B. To C will integrate into the home storage system, build its channels, promote its brands, and have certain consumption attributes. To B is a general product supplier who sells products to integrators without consumption attributes and earns material costs and processing fees.
2) System integrator
They can purchase battery cells or energy storage inverters if they do not have complete product production capacity. Some enterprises also produce certain components to do simple system product integration. However, they have channel sales resources and rely on existing channels to cooperate with local dealers and installers.
Connect with upstream integrators and deliver to end users upon completion of installation and construction to earn a royalty on sales and installation fees.
5. Pricing model of household energy storage
The price difference between household energy storage at home and abroad is large, higher than that of industrial and commercial energy storage and MW energy storage. The price in foreign countries is nearly 133% higher than in China (based on the highest price). CIF is the main price, and the seller bears the main risk. Presently, the domestic price of household storage products within 30kWH is 1.0-1.5 yuan /Wh, and the foreign price is 2.0-3.5 yuan /Wh, including the cell and BMS as well as the shell. The wiring harness is connected with a 10-year warranty.
Quotation methods include EXW ex-factory price, FOB price, CIF price, and DDP price. The quotation consists of the price of goods, parts, and FOB/CIF/DDP. Currently, most quotations are CIF, and the sellers bear higher risks.
Overseas terminal pricing is higher, and dealers and installers mark up 30%-50%.
Presently, domestic pricing is low, guaranteeing 20%-30% gross profit. The gross profit of all-in-one machines is higher than that of only selling batteries or inverters.
Under the overseas pricing model, labour wages and overseas travel expenses increase costs. In addition, about 5% of repair/after-sales expenses should be considered. The overseas sales price will be increased by 30-50% by dealers and installers, respectively.
6. Cost split of household energy storage
Household energy storage is matched with the household photovoltaic optical storage system. The optical storage system mainly includes a battery, energy storage inverter (two-way converter), component system, and other parts. A typical system is 5KW (component + inverter) with 10KWH (energy storage battery) or 10KW+10KWH. An electric cell is the core of the energy storage system, and the cost accounts for about 45-50%; The energy storage converter can control charge and discharge and carry out AC/DC conversion. The cost accounts for about 10-15%. Module system, namely photovoltaic system, is used for solar power generation, accounting for about 20-25% of the cost; The installation cost increased from 10,000 yuan in 2021 to about 20,000 yuan, accounting for 15-20%.