[Tech 스토리] Volkswagen’s’square’ battery…is it superior to the pouch?

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[서울=뉴스핌] Reporter Yoonae Lee = The K-Battery, which was winning and winning by taking the No. 1 global market share, is in crisis. This is because Volkswagen, the number one car sales in the world, declared’battery independence’. Volkswagen has been using the’pouch type’ battery that LG Energy Solution and SK Innovation mainly produce, but in the future, it is said that it will adopt a’square type’.

Volkswagen introduced a new integrated battery cell called’Unified Cell’ from 2023 through’Power Day’, the first battery day event on the 15th (local time). I made a plan to mount it. At the event, Volkswagen also added, “The prismatic battery is the best condition for the transition to an all-solid-state battery that the group expects to make a leap forward in the next five years.”

Ralph Brandstatter, CEO of Volkswagen Brand[사진=폭스바겐]

Why is a prismatic battery more’optimal’ than a pouch type or a cylindrical type? What is the superiority of the square, which has been’selected’ by Volkswagen, the world’s number one car salesman, than the pouch type and the cylinder type?

◆ Battery cell shape, square, pouch type, cylinder type… what’s different

Currently, lithium-ion batteries used in electric vehicles are made in three shapes: square, pouch type, and round shape. Battery manufacturers make the four major materials used in lithium-ion batteries, such as cathode materials, anode materials, separators, and electrolytes, but supply them in different forms.

The’square battery’ that Volkswagen chose this time looks like an aluminum can. The easiest thing to think of is the battery that was used as a detachable cell phone in the past. Recently, it is also mainly used for laptops. Among the three domestic battery companies, Samsung SDI mainly produces them.

The square shape is thinner than the cylinder type, and it is in the form of a metal can, which is more durable than the pouch type. Recently, CATL, a Chinese battery company, produced LFP (lithium iron phosphate) batteries and supplied them to Tesla, drawing attention from the industry. The advantages of LFP were low cost and low fire risk. However, it is pointed out that its competitiveness in terms of fuel economy and mileage is low because it is relatively heavy using cans.

LG Energy Solution and SK Innovation mainly produce’pouch-type batteries’. Currently, there are only two battery companies that can mass-produce pouch types.

[서울=뉴스핌] Reporter Yoonae Lee = Square, Pouch Type, Cylindrical Battery 2021.03.19 [email protected]

A pouch type battery consists of a thin aluminum foil wrapped around the battery components. Unlike the square and cylinder, which is surrounded by metal, it is made of a flexible pouch to make a thin and wide battery. Therefore, it is relatively light in weight and can be processed. Various shapes are available to meet the various needs of automotive OEMs around the world. However, the disadvantage is that the production cost is relatively high compared to the square and cylinder.

Finally, the’cylindrical battery’ can be thought of as a battery that you often see around you. It is known as the most traditional battery and used by Tesla, the United States, the world’s number one electric vehicle.

Cylindrical batteries have a standardized size, so they are the cheapest and have no stability and supply problems. However, it cannot produce high energy per battery cell, and frequent charging and discharging may reduce performance compared to other types of batteries.

◆ The world’s No. 1 electric vehicle market’China’ also uses prismatic batteries

In the industry, it is difficult to say superiority because all three types of batteries have their strengths and weaknesses, and it is argued that they are supplied according to the preferred batteries for each automaker.

However, competition for technology development to complement the weaknesses of each battery and maximize its strengths is heating up.

According to SNE Research, a market research institute, the square type was the highest with 49.2% (70.8GWh) of the three types based on the annual battery usage of EVs and PHEVs installed last year. After that, pouch type 27.8% (40GWh), cylindrical 23.0% (33.2GWh) in that order.

Prismatic batteries are produced by Chinese battery makers CATL and BYD, the world’s number one electric vehicle market. Samsung SDI is also square.

The cylinder is mainly used by Tesla, and is produced by Panasonic and LG Energy Solutions in Japan. Other pouch types are mainly used in Europe and the United States, with LG Energy Solutions and SK Innovation being the main battery makers.

Looking at the year-on-year growth rate, there are significant results. The pouch-type battery showed the largest increase compared to the previous year at 111.6% (18.9 → 40.0GWh). On the other hand, the square type increased by 5.5% (67.1 → 70.8GWh) compared to the previous year, and the cylindrical type increased by only 3.6% (32.0 → 33.2GWh).

SNE said, “As the European electric vehicle market is expected to maintain growth this year and the Chinese and US markets will continue to recover, the scale of all three types will increase steadily.” We will keep it, but the fluctuation will be somewhat less than last year.”

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