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Large capacity battery technology preparing for a blackout


Large capacity battery technology  preparing for a blackout

The words frequently bandied about recently include ‘Blackout’. It represents a large scale power failure that occurs because supply of power fails to catch up with the demand. It is so named because an entire city becomes literally a world of darkness as no electricity is supplied. The worst blackout in the history which occurred in the eastern area of USA in 2003 showed what will happen when a blackout occurs in a large modern city. During the blackout in 2003, the supply of electricity to 7 US states including New York, New Jersey, Ohio and Michigan and to Ontario State of Canada was completely cut off. The number of residents who suffered from the blackout was as big as 50 million, and the damage was estimated to be US$6 billion (about KRW6.15 trillion).


Energy storage system and secondary battery

In Korea, the likeliness of blackout is also rising recently. It is because not only the demand for cooling in the summer has rapidly increased due to increase in the average temperature caused by climate change but also nuclear power plants stop power generation more frequently. As the supply is marching in place while demand is increasing, it seems that we will have a difficulty in getting out of the rick of blackout for some time.  

The way to prevent blackout, of course, is to increase supply by building more power plants. But, a careful plan is required to be established for construction of a new power plant and it also takes much money. Accordingly, the most rational and feasible way is ‘to store electricity’. As demand for electricity changes from moment to moment while supply of electricity can be constantly maintained to some extent, blackout can be prepared for if electric energy is stored when there is a big surplus and used when there is a shortage. It is to make a kind of buffer. That is the very ESS (Energy Storage System). 

An ESS that can be used as an auxiliary power source should have a big capacity. It is because electricity should be supplied not to a single building but to a whole city. The key of such a system is the very high efficiency secondary battery which corresponds to a ‘container in which electricity is stored’. As secondary battery can also be grafted to adjacent fields such as electronic equipment or electric car, the efficiency of electric energy system can be enhanced as a whole if the related technologies progress. It can also play a key role in the future energy system by enhancing utilization of diverse renewable energy resources and stabilizing energy supply systems.  

The secondary battery technology is also importantly related to national security. The key raw material of medium-sized/large secondary batteries is lithium, and its supply is extremely unstable because it is produced by only a limited number of countries. The total quantity of lithium used in Korea is also imported. If the demand for lithium increases as a result of industrial development of developing countries, it will apparently become more and more difficult to get supply of lithium. Accordingly, also in the aspect of energy security, we have to develop technologies that enable us to use other materials than lithium or to recycle waste batteries to the maximum.


Going beyond lithium ion battery

electronic car

The backup power system, an ESS that stores electricity and utilizes it as backup power in a high rise building  (left)

An electric car being charged in the downtown of Hamburg, Germany (right)

A secondary battery is a device that stores or converts electric energy using electrochemical reactions. Accordingly, when charging a secondary battery, electric energy is stored in chemical energy, while, when discharging, chemical energy is used being converted to electric energy. As secondary battery has an advantage that it can be transported with the electricity stored or kept, it is widely utilized in diverse fields.

A representative secondary battery is the very lithium battery. In 1991, Sony, Japan, has successfully commercialized lithium secondary battery. The new battery of Sony was totally different for the past batteries. Not only highly efficient charging was possible, the service life was long, the voltage characteristics were superior, but also it could be produced in different shapes. Later, the lithium secondary batteries were rapidly supplied to the extent that it was called a revolution, and the entire industry started rapid growth. 

As the market grew, Samsung SDI and LG Chemical of Korea jumped into the market in the beginning of the 1990s, and then Chinese companies started lithium secondary battery business in the early part of the 2000s. At present, Korea, China and Japan are competing with each other in the lithium ion battery market, and the related technologies have rapidly progressed and started to be utilized for large scale applications such as automobile or energy storage system fields. KIST have carried out studies related to lithium secondary battery for about 20 years to achieve many fruits, and is recently carrying out studies on the original technology of large capacity secondary battery, new materials for lithium ion battery, and waste battery recycling technology.     

Studies on a new form of battery using lithium other than the existing lithium ion battery are also active. That is the very ‘lithium-air battery’. Metal-air battery means a battery where electricity is generated by the oxidation reaction of metal occurring at the cathode and the reducing reaction of oxygen in the air at the anode. As air battery uses oxygen in the air, the charging capacity by unit volume can be increased by decreasing the weight and volume of the anode material. In particular, in the case of primary battery, as the entire battery does not need to be replaced but only the cathode material has to be replaced, it is receiving spotlight as an emergency power generation battery. 

It is not only lithium that is used as the cathode of a metal-air battery. Magnesium, aluminum or zinc is used as the cathode material for a primary battery, and zinc-air battery is attracting attention among secondary battery. But, as the energy density of lithium is the highest, air batteries using lithium are actively studied. However, as the charging and discharging characteristics of lithium-air batteries have not been determined properly yet, there still is a long way to go until commercialization. 

Though lithium secondary battery is most preferred as the secondary battery for ESS and electric car as its energy density is the highest among the secondary battery known up to now, it is expected that there will be much difficulty in getting supply of the key materials such as lithium because the market is predicted to continuously grow in the future. As it is a problem directly related to energy and industrial security, a secondary battery technology which does not rely on lithium is necessary. The material which attracts attention recently is magnesium. 

Magnesium secondary battery uses magnesium metal as the cathode and a compound magnesium can be easily inserted into and seceded from is used as the anode. As the deposit of magnesium is big in comparison to lithium, it can be stably supplied. In particular, as its domestic deposit is big, we do not have to depend on import like lithium. As the stability is also predicted to be superior to lithium battery, it is expected to be suitable for large capacity storage device.       

However, as the development of magnesium battery technology is at the initial stage, more studies on anode and electrolyte materials are required to be carried out. 

Besides magnesium, sodium is also attracting attention as a secondary battery material. Sodium secondary battery is largely divided into high temperature type sodium-sulfur (NaS) battery and room temperature sodium ion battery. High temperature NaS battery has been commercialized in Japan and is at the stage of demonstration as a large scale electricity storage system, and, in Korea, the overall NaS battery system including mass production technology of beta alumina which is the key is being developed.  

The principle of sodium ion battery is similar to that of the existing lithium ion battery just like magnesium ion battery. As sodium not only abundantly exists in nature but also is easy to collect, studies on sodium as a substitute material for lithium are actively carried out in many countries. KIST is developing sulfur electrode for NaS battery and beta alumina surface treatment technology through the ‘NaS Single Cell Electrochemical Characteristics and Reliability Evaluation Project, and is also carrying out studies on oxide anode material for sodium ion battery and carbon based cathode material. 


The future of energy technology depends on the next generation secondary battery

lithium ion battery

If so, how will the secondary battery technology change in detail for 5 years from now? First, electric cars will move around lithium secondary batteries of which the energy density is the highest and new materials will be actively developed to lower the price and improve the performance. However, it is urgently required to resolve the problem of stability which is the disadvantage of lithium secondary battery, and the tasks are to reduce the total time it takes for charging and guarantee a long driving distance.       

Though large capacity lithium secondary batteries ranging from several hundred kWh to several MWh class are developed, they are not sufficiently proved in the aspect of stability, price and service life. Domestic companies led by Samsung SDI and LG Chemical are accelerating commercialization of lithium secondary batteries for electric cars and ESS, and KIST is carrying out R&D of 5V class high capacity metal oxide based anode material, highly stable phosphate based anode material, and high voltage electrolyte material. 

For magnesium battery, the existing materials will be utilized for a while as it is difficult to develop anode material, and the flow of developing highly stable, long life and low price batteries making best use of the advantage of magnesium secondary battery will be the main stream. Though not many domestic companies are interested in it because it is still at the initial stage of technology development, new anode and electrolyte materials are actively developed by KETI (Korea Electronics Technology Institute) and some universities. KIST seems to be also capable of commercializing magnesium batteries within several years through studies on performance improvement of the existing materials. 

Redex Flow Battery is suitable as a battery for a large capacity ESS ranging from several hundred kWh to several MWh class, and, as it is on a verification test now, it is expected to be commercialized within several years. But, an intensive study is required to be carried out around development of a new redex couple for improvement of the performance. In Korea, companies led by Lotte Chemical are accelerating commercialization of zinc-bromine redox flow battery for ESS, and KIST is concentrating on new redox couple study.

In the case of metal-air battery, development of a secondary battery is still far away. Accordingly, new sources of demand are required to be developed by improving the performance of the existing primary batteries. It is highly likely that metal-air batteries will be commercialized as emergency power generation battery systems in preparation for an emergency such as disaster or power failure in the future. In Korea, some small/medium-sized companies are promoting commercialization of metal-air batteries for emergency power generation, and KERI (Korea Electrotechnology Research Institute) is concentrating on development of an air electrode and electrolyte. 

Sodium secondary battery is a battery that can resolve the problem of lithium exhaustion, and, for the time being, the basic studies on development of new anode and cathode materials and electrolyte will be the main stream. Though very few domestic companies are interested in it as it is at the initial stage of technology development, government-funded research institutes and some of universities are concentrating on development of new anode, cathode and electrolyte materials.  


R&D of advanced countries and China’s chase should be overcome


The backup power system, an ESS that stores electricity and utilizes it as backup power in a high rise building  (left)

An electric car being charged in the downtown of Hamburg, Germany (right)

The medium sized/large secondary battery market is expected to rapidly grow in the future. Advanced countries are striving to secure the basic and original technologies by expanding R&D investment and accelerating international M&A through establishment of nation-wide support system to preoccupy this market. Though Korea, Japan and China are leading the world market at present, USA and Europe are also attempting to take the lead in the next generation secondary battery industry by securing the next generation original technology.

lithium mine

Lithium mine in Austria. Though lithium is the best material for secondary battery at present, its deposit is not big. 

Accordingly, sodium, magnesium, etc. are attracting attention as materials for secondary battery in place of lithium. 

In the lithium secondary battery market in which Korea is maintaining the number one position, change is expected. Though the current lithium secondary battery market is formed around small size secondary batteries for mobile IT, the market will rapidly grow in the future around the secondary batteries for electric car and ESS. In particular, the secondary battery for electric car is predicted to grow by 34 % or more every year. 

Korea started development of small size lithium secondary battery from the latter part of the 1990s and accounts for the biggest market share in the world at present overtaking Japan by achieving rapid growth for last 10 years. However, among many types of secondary batteries, the competitiveness of Korea is limited only to lithium secondary battery. Moreover, Korea’s competitiveness is superior only in the market of small size lithium battery for mobile IT, and Korea lacks overall part and material technologies. The technical ability of Korea is known to be somewhat poor as it is only 80 % or less of that of Japan when the all parts and materials are compared and 60 % or less when the original technology is compared.

For medium-sized/large secondary batteries for electric cars and ESS, major advanced countries are carrying out wide range of studies from basics to applications. Accordingly, if we want to catch up advanced countries, Korea should concentrate on enhancing the efficiency of investment. In particular, supports should be concentrated on basic/original technologies and part/material technologies for which Korea has not yet secured competitiveness relatively. In addition, as the secondary battery market is divided by application, investment should be made evenly in the technologies of diverse battery types. 

Secondary battery technology is a field for which multidisciplinary joint studies including electrochemistry, material engineering, chemical engineering, chemistry, and physics are required and studies have to be carried out across the entire cycle from basic research to commercialization research. Accordingly, a government level integrated technology development system which enables performance of convergence study jointly by industries, schools and research institutes is acutely required to be established.    


battery market graph

Secondary battery market prediction graph. 

The share of lithium secondary market is expected to grow rapidly and accounts for 66 % or more of the total market in 2020.

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