LR03 alkaline battery

Graphene and supercapacitors, who will dominate the technology of LR03 alkaline battery?

1. Graphene battery: miracle or illusion?

Anyone who pays a little attention to new technologies will know what graphene is and how much expectations are placed on this material.

Since Sony invented lithium-ion batteries in 1991, lithium-ion battery technology has been almost like a straight line, with some waves but not enough amplitude. This bottleneck has been here for nearly 15 years, and Moore's Law is regarded as nothing, with no intention of loosening.

Then one day in 2004, graphene was born and helped two scientists win the Nobel Prize. In the following days, all kinds of hype were overwhelming, and the most attractive one was the concept of graphene batteries.

Graphene batteries refer to a new type of battery developed by utilizing the characteristics of lithium ions moving quickly and in large quantities between the graphene surface and the electrode. So is this battery a miracle that brings a new era, or a short-lived illusion?

What does a graphene battery look like?

Universal materials are to solve the anxiety of battery life

Graphene is called a universal material, and it has great potential in all major scientific and technological fields. So how did graphene batteries plant the seeds of hope in the increasingly irritable battery industry?

First, let's take a look at the magic of graphene batteries. The energy density of graphene batteries is as high as 600Wh/kg, which is 4 times the energy density of BYD's iron manganese phosphate lithium-ion battery (unconfirmed) that made a lot of noise a while ago. In other words, if an electric car wants to achieve the set total energy of the power battery pack, the weight of the graphene battery only needs one-eighth of that of an ordinary power lithium battery (the weight of the graphene battery itself is only half of that of a traditional battery), which can reduce the weight of the car body, or add battery weight, so as to achieve the purpose of getting rid of battery life anxiety.

In addition to the biggest advantage of energy density, graphene batteries have other killer features. Its service life is twice that of ordinary lithium-ion batteries, and its manufacturing cost is 77% lower than that.

And it is Tesla Motors that really makes this magic battery the international focus. At the end of last year, Tesla announced an upgraded version of the first-generation Roadster, which was discontinued two years ago. Its range is as high as 644 kilometers, while the original Roadster's range is only 393 kilometers). As soon as the news came out, everyone was shocked.

Behind the great progress, there must be major changes. The ultra-long range of Tesla's upgraded Roadster has aroused people's strong curiosity. People have speculated whether it uses high-energy-density graphene batteries? However, Tesla officially announced that the upgraded Roadster uses improved lithium-ion batteries, and kept silent about the topic of graphene batteries.

Graphene structure

Charging for 5 minutes to run 1,000 kilometers is just fake news?

Another company that has attracted much attention for graphene batteries is the Spanish Graphenano company. The company cooperated with the University of Corvado in Spain to develop the world's first graphene polymer material battery, and through experiments, it claimed that electric vehicles powered by graphene batteries can travel up to 1,000 kilometers, and the charging time is not even 8 minutes!

This news shocked the global electric vehicle industry at the time. With such powerful performance, is the world about to open a new chapter? Think about it calmly. It takes less than 8 minutes to fully charge. How strong a current is needed? Let's take the Nissan Leaf as an example to calculate. 1 kWh of electricity can run about 5 kilometers. Converted to 1,000 kilometers, it requires 20kWh of electricity. Calculated as 8 minutes to fully charge, it needs to charge 150kWh per hour, which is equivalent to 300A of current under high voltage (500V). The wire that can withstand 300A current is scary to think about.

Western media reported that this super battery will be produced and put on the market in the first quarter of 2015, but now the second quarter has ended and we have not seen the appearance of this magical thing. Combined with the general view of domestic experts: Spain's super battery is just fake news. The graphene battery currently launched is a bit sad. The application of graphene in lithium-ion batteries is only a few tenths of a percent of additives, and no company can really launch a product.

2. Expecting supercapacitors is not as good as relying on graphene

Are supercapacitors more reliable than superbatteries?

What is a supercapacitor? A supercapacitor is an electrochemical element used for energy storage, which is different from traditional capacitors and even more different from batteries. It is also called a double-layer capacitor and has many advantages: high power density, short charging and discharging time, long cycle life, wide operating temperature range, simple charging and discharging circuit, safety and reliability, etc.

Let's take a closer look at the difference between it and lithium-ion batteries.

(1) High power density, which can reach 300W/kg~5000W/kg, which is equivalent to 2~30 times that of lithium-ion batteries;

(2) Short charging and discharging time, charging for 10 seconds to 10 minutes can reach more than 95% of its rated capacity;

(2) Long cycle life, deep charging and discharging can be used for more than 500,000 times, which is 500 times that of ordinary lithium-ion batteries. That is, if a supercapacitor is charged and discharged 20 times a day, it can still be used for 68 years. The reason is that no chemical reaction occurs during the energy storage process, and the energy storage process is reversible, so supercapacitors can be charged and discharged repeatedly for hundreds of thousands of times;

(4) Wide operating temperature range, good ultra-low temperature characteristics, wide temperature range of -40℃～+70℃, which is beyond the reach of pampered lithium-ion batteries;

(5) Simple charging and discharging circuits, no need for charging circuits like rechargeable batteries;

(6) High safety factor, long-term maintenance-free, no explosion and fire problems.

Such advantages are not inferior to graphene superbatteries, and supercapacitor buses have already appeared, which naturally has an extra layer of realistic texture compared to the latter. In the new energy vehicle industry, people have great expectations for supercapacitors.

Supercapacitor structure diagram

Disadvantages cannot be ignored, but the reality is exciting

All these are the advantages of supercapacitors. But just like a coin has two sides, supercapacitors also have disadvantages that cannot be ignored.

The installation position of supercapacitors is particular. If it is not reasonable, it is easy to cause electrolyte leakage and other problems, which will damage the structural performance of the capacitor. Although the charging and discharging circuit of supercapacitors is simple, it is limited to the use of DC circuits. Its internal resistance is relatively large and is not suitable for the operation requirements of AC circuits. Then, since supercapacitors are a new generation of high-tech products, the price is relatively high. One charge is only enough for electric vehicles to travel a few kilometers. The price of energy storage products per kilowatt-hour is nearly 10 times that of batteries, and the actual cost of operation will be very high. These problems are the bottlenecks that make it difficult for supercapacitors to be widely promoted and used alone in electric vehicle applications.

Can you imagine a situation where a bus runs to a station and then needs to be charged once? In this case, we need to set up many charging devices along the bus route (fortunately, supercapacitors charge quickly, and the electricity can be charged when passengers get on and off the bus).

It was also tested at the 2010 Shanghai World Expo. Zhongshang Automobile in Changsha, Hunan has reached a new height in the development of supercapacitors. The capacity of the current demonstration application can reach 150,000 farads. This supercapacitor public vehicle can travel up to about 20 kilometers at a time, and the charging time is only about 3 minutes.

At the 6th International Battery Industry Exhibition, Shanghai Aowei Technology Development Co., Ltd. also displayed a new supercapacitor, which has an energy density of more than 50% higher than that of ordinary supercapacitors, but slightly lower power, making it more suitable for use on buses, so that supercapacitor buses that originally needed to be charged frequently can run 20 kilometers at a time.

In this way, supercapacitors are more like a game-changer for range anxiety than graphene batteries.

What does a supercapacitor look like?

3. Market analysis and outlook

At present, supercapacitors have been used as energy storage components, and their use effect is remarkable, but their important role is still the supporting role. Because in a short period of time, supercapacitors have their limitations. Except for electric buses, they cannot be used as a universal and independent energy storage power source for vehicles.

In May this year, the Ministry of Finance and other ministries and commissions officially announced the "Notice on Improving the Subsidy Policy for the Price of Finished Oil for Urban Buses to Accelerate the Promotion and Application of New Energy Vehicles". It is learned that each lithium-ion bus over 10 meters can be subsidized up to 80,000 yuan per year, while the same supercapacitor bus can only be subsidized 20,000 yuan per year. Calculated based on the operation of each vehicle for 8 years, there is a subsidy gap of 480,000 yuan per vehicle. The country seems to have always believed that the research and development of supercapacitors is alternative. But supercapacitor vehicles are just getting started, and everything is decided by the choice of the market, and government subsidies are secondary.

Unlike supercapacitors, graphene has received great attention from the country, and many institutions are also studying this two-dimensional material. But these studies are obviously scattered, and what the country needs to do is to divide them all and then integrate them. In this way, mass production of graphene in 2015 has become an expectation, which is also good news for super batteries. Let us look forward to the remaining six months of 2015.

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