【Scientific and Technological Achievements Promotion】 Lithium-ion Supercapacitors

With the rapid development of the global economy, the rapid consumption of fossil energy and the worsening of environmental pollution, the human demand for sustainable and renewable energy is increasing, which has inspired researchers to study efficient and clean energy conversion and storage devices. Among the many energy storage devices, supercapacitor is a new type of energy storage device developed in the 1970 s and 1980 s. It has excellent pulse charge and discharge performance, power density is higher than that of batteries, and energy density is higher than that of traditional capacitors.

What I want to introduce to you today isInnovative product lithium-ion supercapacitor developed by the Micro-nano Energy Research Center of our hospital, let's understand its research and development process and application together ~

science and technology research and development]

First of all, I will give you a simple science about the basic principles of lithium-ion supercapacitors.

What is a lithium-ion capacitor?

Simple science on the basic principles of lithium-ion supercapacitors. Up to now, the super capacitor technology has been more mature, is well known, it is a kind of product between the capacitor and the battery. What we are showing today is a lithium-ion supercapacitor. As the name suggests, this is an energy storage device between a lithium-ion battery and a supercapacitor. Its main principle is to pre-dope lithium ions through the negative electrode to make the negative electrode The potential is almost matched with the lithium potential, which can significantly increase the working voltage of the device to 3.8 or even 4V or more.

Lithium-ion super capacitor working principle diagram

 

Compared with lithium-ion batteries and supercapacitors, the characteristics of lithium-ion supercapacitors are mainly reflected in:

Compared with batteries, supercapacitors have many advantages such as a wide range of operating temperatures (from -40°C to 70°C), high energy density (up to 5kWh/kg), and green raw materials. And its life is also very adverse, can withstand 50-1 million times of charge and discharge deep cycle, and ordinary batteries if experienced 1000 times of deep cycle, it is estimated that it can not be used.

Although supercapacitors are also an energy storage system, they are different from ordinary batteries as we know them. If you compare ordinary lithium batteries to gasoline, then supercapacitors are explosives. The charging and discharging speed of supercapacitors is very fast, far exceeding that of traditional batteries.

However, there are also disadvantages, that is, the long-term discharge capacity of supercapacitors is not as good as that of batteries, so they cannot be used for continuous trickle energy output. And the super capacitor can not be charged with alternating current, can only be charged in a dedicated DC charging station.

 

science and technology innovation]

The lithium-ion supercapacitor products developed by our institute have the energy storage characteristics of "high power density" of capacitors and "high energy density" of lithium-ion secondary batteries, and have the characteristics of good charge/discharge cycle characteristics, long life, high temperature resistance and high safety.

Compared with the current traditional electric double-layer supercapacitor, the lithium-ion supercapacitor greatly improves the energy density of the device while maintaining its high-power discharge characteristics. Under the same operating conditions, the battery volume can be saved by more than three times. At the same time, due to the doping of lithium, the negative electrode potential is stabilized, making the lithium-ion capacitor have excellent self-discharge characteristics. It can be clearly seen from the comparison of the self-discharge curves of the electric double-layer and lithium-lithium-ion capacitors, under normal temperature conditions, the voltage of the electric double layer capacitor drops to 80% of the initial voltage after one month, while the lithium ion capacitor can maintain a voltage of more than 3.7V even after 100 days.

Lithium-ion batteries in order to achieve a long life, the depth of charge and discharge has a certain range of restrictions, which reduces the actual capacity can be used, the charge and discharge principle of the electric double layer capacitor is simply to absorb or off the electrolyte ions and has a long life, only this is difficult to extend the actual life. However, even when the positive electrode potential of the lithium ion capacitor is lowered, the voltage of the cell itself does not significantly decrease, and thus the capacity can be ensured.

Performance comparison

Under high-temperature conditions, the electrolytic solution and the positive electrode are likely to undergo oxidative decomposition, and therefore, it may be necessary to lower the potential of the positive electrode under high-temperature conditions. However, when the potential is lowered, the overall voltage of the electric double layer capacitor decreases, and the capacity cannot be ensured. The lithium-ion battery can not be reduced, easy to produce safety problems. Only the lithium ion capacitor can be used at a position where the positive electrode potential is far away from the oxidation decomposition region, and thus is excellent in high temperature performance.

In terms of safety, compared with the use of metal oxides in the positive electrode of lithium batteries, the positive electrode of lithium-ion capacitors uses oxygen-free activated carbon. When an internal short circuit occurs, as the temperature rises, the positive electrode does not react with the electrolyte., There will be no thermal runaway, in theory, it will be much safer than lithium batteries.

 

industrial application]

Product application areas and types

Application Scenario Case Event Smart Water Meter

NB-IOT to the power consumption of the Internet of Things water meter, the intelligent water meter adopts the hardware architecture of MCU NB-IOT. When the MCU of the intelligent water meter is idle (standby power consumption is 10uA), the NB-IOT network is turned on only when data needs to be uploaded. The working time for each data upload is about 15s and the working current is about 150mA. Assuming that the data is uploaded once a day, the water meter consumes power for one year;

Power consumption/year = 10uA * 24h * 365 150mA * 15/3600*365=315mAh;

If the design life of the Internet of Things water meter is more than 6 years, the power consumption is: 1890mAh;

Select the LIC ER combination to meet capacity, power and operating life requirements.

Intelligent water meter

Application Scenario Case-Sharing Bicycle

Low temperature unlocking;

NB-IOT reported information, Bluetooth alternative unlock.

Application Scenario Case Event ETC

The working states of the high-sensitivity OBU system module are divided into: sleep, pre-transaction, and transaction. The largest power consumption in the whole process is the card reading process in the transaction state, and the instantaneous current can reach 150mA;

The vast majority of OBU systems in China's market trade less than 10 times a day, or even less than 1 time;

The power supply is required to be 1000mAh, which can reach a cumulative transaction of 20000 times and a service life of more than 5 years.

ETC power supply use characteristics requirements

1. Discharge requirements for extreme outdoor weather

2, long life

3, high reliability

4. Safety

5. Instantaneous high current pulse discharge

Application Scenario Case Event Backup Power Supply

For equipment such as manufacturing devices and medical machines, even a momentary voltage drop can cause fatal injuries. Taking advantage of the extremely high temperature reliability of lithium ion capacitors, which can be exerted in a narrow space with heat sources, lithium ion capacitors can be used as decentralized, selective backup power supplies and auxiliary power supplies, such as server CPU, DRAM, RAID controller, SSD and other components, backup power supplies when machines stop instantaneously, etc. From the perspective of power storage, lithium ion capacitors can be used as regenerative energy for automobiles, trucks and elevators.

 

Micro-nano Energy Research Center

The Micro-nano Energy Research Center of our institute was established in 2017. It has strong technical accumulation and rich industrialization experience in the fields of new materials and new energy, and has been committed to the research of micro-nano energy devices for a long time. Based on many years of experience in the design, development and application of micro-nano energy products, the research center has made breakthroughs in the research and development of new mechanisms, new materials and new processes of supercapacitors, micro-energy systems and intelligent micro-systems, and is committed to the research and development and manufacturing of new energy technologies represented by the third generation of large-capacity lithium-ion capacitors. At present, there are two production lines for micro and small batteries and capacitors. It has a dry operation room and a full set of high and low temperature, vibration, damp heat and other environmental testing equipment. It can develop and batch produce dozens of models of supercapacitor products. The products are widely used in smart microgrids, Smart meters, rail transit, new energy power generation, construction machinery and other fields.

 

Technical docking and business negotiation

Contact: Jiang Bin

Fixed telephone: 022-58205388

Mobile Phone: 13512447351

E-mail: 13512447351@163.com

 

Source | Micro-nano Energy Research Center

Editor | Wang Xiao

The final interpretation of the above related technologies belongs to the Micro-nano Energy Research Center.