Supercapacitor battery : power energy storage black technology

Since 2022, supercapacitors have been used in China for the first time in integrated fire-storage peak shaving and frequency regulation, primary frequency regulation, and shore-storage integration projects for the first time. The supercapacitor battery industry is ushering in an accelerated inflection point.

Supercapacitors are power energy storage devices

Supercapacitor has broad prospects in the fields of power grid frequency regulation, hybrid energy storage and automobiles. The acceleration of the industry requires:

1. Improving the energy density of supercapacitors;
2. Large-scale mass production & localization of the industrial chain;
3. More clear demand scenarios.

Supercapacitor and energy-based lithium battery complement each other

Supercapacitors are power energy storage devices with higher energy density. Compared with batteries, it has higher power density and is a new type of power energy storage device. It has the characteristics of short charging time, long service life, good temperature characteristics and green environmental protection. Supercapacitor battery has been widely used in consumer electronics, industry, defense and military industries as backup power supplies, power supplies, and energy recovery systems.

At present, the energy density of hybrid supercapacitor battery has been greatly improved, and the localization of raw materials has driven the continuous reduction of supercapacity costs. Supercapacitors are electrochemical energy storage devices, which are mainly composed of positive and negative electrodes, electrolytes, and diaphragms to prevent short circuits. The electrode material has the characteristics of high specific surface area. The separator is generally an electronic insulating material with a fiber structure. The lithium ion battery electrolyte is selected according to the properties of the electrode material.

Taking the mainstream electric double layer capacitor in the market as an example, when charging, the positive and negative ions in the electrolyte move rapidly to the two poles under the action of the electric field, and the electric double layer is formed at the interface between the electrode and the electrolyte to store the charge. Benefiting from the unique structure and working principle, supercapacitor battery has excellent characteristics such as high power density, high reliability, and environmental protection.

High power characteristics: Different from lithium batteries when charging, lithium ions need to be combined with charges and embedded in the micropores of the negative electrode carbon layer, and need to be de-embedded from the negative electrode carbon layer during discharge, and the charge movement of supercapacitor battery during charging and discharging occurs on the electrode surface. , so the supercapacitor power density is significantly higher and the charge and discharge speed is significantly faster.

In contrast, in terms of power density, the supercapacity of the electric double layer can reach up to 40 kW/kg, and the lithium battery is 1 to 3 kW/kg. In terms of charging and discharging time, the EDLC can reach the second level, the HUC is at the minute level, and the lithium battery is at the hour level. High reliability features: In terms of operating temperature, the operating temperature range of lithium batteries is −20 to +60°C, and the operating temperature range of super capacitors can be as wide as −40 to +85°C.

In terms of working life, since the charge movement during the charging and discharging process is completely reversible, the number of charging and discharging times can reach 1 million times, and the working life can reach 15 years. In addition, the supercapacitor battery will not burn if it is short-circuited or punctured. Compared with lithium batteries that are prone to spontaneous combustion or even explosion when short-circuited or punctured, supercapacitor battery is safer.

Environmental protection features: Supercapacitor battery does not contain heavy metals and harmful chemicals, and their production, use, storage and dismantling processes will not pollute the environment, and are ideal environmentally friendly energy sources. Lithium batteries cannot be decomposed and are prone to serious pollution to the environment. As a power-type energy storage device, supercapacitors complement and synergize with energy-type lithium batteries by virtue of their high power and long cycle life characteristics.

Lithium batteries, as energy-based energy storage devices, have been widely used in various long-term energy storage scenarios. With high power and long cycle life, supercapacitor battery can be used in separate energy storage scenarios with short-term high power and multiple cycle discharges, or form a hybrid energy system with lithium batteries to achieve complementation and synergy with energy-based lithium batteries.

Supercapacitors meet the inflection point of upward acceleration

According to data, the world supercapacitor market will reach US$1.59 billion in 2021 and is expected to reach US$3.7 billion in 2027. The market size CAGR in 21-27 is about 18%. In 2021, the size of China's super capacitor market will reach 2.53 billion RMB, and it is expected to exceed 6 billion RMB in 2027. In 2021-2027, the market size CAGR will exceed 20%. Supercapacitor battery is penetrating into emerging applications such as new energy buses, power grid frequency modulation, energy storage, and vehicle start-stop.

According to the data, the current energy density of hybrid supercapacitor battery can reach 80~160Wh/kg, and the system energy density has exceeded 40Wh/kg. With higher energy density properties and lower cost, hybrid supercapacitor battery have successfully opened the application ceiling in the fields of minute-level energy storage and buses, and continuously expanded the industry boundaries.

The energy density of supercapacitor battery is expected to be further improved. The energy density of supercapacitor battery mainly depends on its specific capacitance and voltage window. Therefore, methods to further improve the energy density include improving the electrode specific capacitance, developing electrolytes in the high electrochemical potential range, optimizing the structure of supercapacitor battery, and reducing the consumption of electrolytes by devices.

With the continuous advancement of technology, according to forecasts, the energy density of supercapacitor systems is expected to increase to 50-100Wh/kg in 2025 and 100-200Wh/kg in 2030. The upstream materials of supercapacitor battery mainly include electrodes, electrolytes, diaphragms, leads, etc. The electrodes, electrolytes, and diaphragms account for about 35%, 30%, and 20% of the cost, respectively.

Among them, the localization of electrolytes is relatively mature, and Xinzhoubang occupies more than 50% of the market share of supercapacitor electrolytes in China. However, electrodes and separators have long relied on imports due to high technical barriers. Among the electrode materials, 70-80% of supercapacitor carbon, the most used and most economical material, is imported from Japan Kuraray.

Diaphragms are mainly imported from the United States, Japan and other countries. Japan's NKK occupies more than 60% of the world's supercapacitor diaphragm market share. Local manufacturers such as RMBli, Beihai Xingshi, and Kaien are vigorously promoting the localization of electrodes and diaphragm materials.

Supercapacitors have broad space in multiple application fields

Supercapacitors participate in the whole process of power grid frequency regulation

The installed capacity of new energy and the proportion of power generation have increased rapidly. As of 2021, China's wind power and photovoltaic installed capacity will be 328GW and 307GW, accounting for 27% of the country's total installed power capacity. In 2021, wind power and photovoltaic power generation will be 655.6 billion kWh and 327 billion kWh, accounting for a total of 27% of the country's total power generation.

The proportion of wind power and photovoltaic power generation in the total electricity consumption will continue to increase, reaching about 16.5% in 2025. The supercapacitor battery is adapted to the short-term high-frequency and high-power frequency modulation requirements of the power grid, and the applications on the power generation side, transmission and distribution side, and power consumption side are gradually implemented. Supercapacitor battery adapts to the short-term high-frequency and high-power frequency modulation requirements of the grid by virtue of their high-power and long-life characteristics.

Supercapacitors are suitable for automotive applications

Transportation

The transportation field is similar to the automobile field. Supercapacitor battery can mainly realize three functions of energy storage/backup power supply, engine starting, and energy recovery in application scenarios such as rail transit, buses, trucks, and ships. At the same time, it can also be used to realize functions in specific scenarios, such as ship generator control gradient and heave compensation, and catenary-free operation of rail transit.

Rail transit vehicles use super capacitors to achieve braking energy recovery and high-power charging and discharging at the moment of start and stop. The braking energy recovery and utilization system of rail transit vehicles is composed of super capacitors connected in parallel with batteries to realize the recovery of electric energy during train braking.

Industry

In the smart meter scenario, the supercapacitor battery is used as a backup power supply for the internal RTC circuit, which simplifies the design of the charging and discharging circuit and ensures the long-term reliable operation of the smart meter. The advantage of supercapacitor batttery as a backup power supply for the RTC circuit inside the smart meter is that it can meet the strict operating temperature requirements of the smart meter from -40°C to +85°C, and its long working life can ensure the long-term reliable operation of the smart meter.

The relatively indirect charge and discharge management circuit design of supercapacitor battery can simplify the design of RTC backup power supply. At present, supercapacitor batteries are used as the RTC to maintain the backup power supply and keep the RTC circuit running accurately for more than 48 hours, so as to realize the purpose of replacing the built-in battery.

Super capacitor supply side

The scale of China's supercapacitor battery market is growing rapidly. In 2021, the world supercapacitor battery market size by region, the Asia-Pacific region ranks first with a share of 39%, and China is the country with the largest supercapacitor battery market in the Asia-Pacific region.

In 2021, its market size will reach 2.53 billion RMB, accounting for 24% of the world's share, and the year-on-year growth rate of the Chinese market size will reach 32%, much higher than the 15% year-on-year growth rate of the world market. With the joint efforts of manufacturers in all links of China's local supercapacitor battery industry chain, China is expected to lead the development of the world's supercapacitor battery industry.

Summary

The localization rate of supercapacitor battery continues to increase, and local manufacturers usher in a high growth inflection point. In 2019, the US supercapacitor leader Maxwell was acquired by Tesla, and the growth rate of its supercapacitor business gradually slowed down. At present, a number of local supercapacitor manufacturers have begun to take shape.

In the future, with the rapid growth of emerging markets such as power grid frequency regulation, hybrid energy storage, and automotive applications, Chinese manufacturers are expected to usher in a high-growth inflection point.

Related article: top 15 power battery companies, thermal energy storage, condensed state battery