[Report] Micro-Scale 'Cathode Material Struggle' at 50,000-Pyeong Factory... POSCO Future M Gwangyang Plant

Visiting POSCO's Battery Heart 'Gwangyang'
① Tour of POSCO Future M Gwangyang Cathode Material Plant

Next-Generation Battery Technology 'Single Crystal Cathode Material' Unveiled
Quality Control with 2000 CCTVs and Air Shooting

Choi Wook, Head of the Cathode Material Production Department at POSCO Future M, is introducing single-particle cathode materials. Photo by POSCO Future M

"The most important aspect in the cathode material process is contamination control. Even a tiny amount of moisture or foreign substances can cause cracks or degrade quality. We manage quality to keep contaminants below 15ppb (parts per billion). That means out of a billion particles, fewer than 15 are contaminants." (Son Dong-gi, Head of Cathode Material Division, POSCO Future M)

On the afternoon of the 20th, at POSCO Future M's cathode material factory located in the Yulchon Industrial Complex, Gwangyang-si, Jeollanam-do. The cathode material factory, covering approximately 165,203㎡ (about 50,000 pyeong), roughly the size of 23 soccer fields, was ironically the site of a struggle to overcome differences measured in micrometers (one-millionth of a meter, ㎛). On this day, the single-particle cathode materials, recently commercialized by domestic cathode material companies, were unveiled to the world for the first time.

POSCO Future M Takes First Step in Next-Generation Battery with Single-Particle Cathode Material Production

Cathode materials are a core component accounting for over 40% of battery costs. Recently, 'high-nickel cathode materials' with nickel content exceeding 80%, which increase driving range and output, have gained attention. However, nickel is an unstable material vulnerable to heat and impact, posing explosion risks. As nickel content increases, this instability grows, and single-particle technology compensates for this.

POSCO Future M anticipates that single-particle cathode materials will lead the battery market in the future. Son Dong-gi said, "I don't think exceeding 90% nickel content is crucial in the cathode material market. Rather, cathode materials with 60-70% nickel content, called 'mid-nickel,' combined with single-particle technology that extends driving range and lifespan, will be favored."

Conventional cathode materials are polycrystalline (multi-particle, about 10㎛) made by clustering metal particles of 2㎛ size. When batteries are used, lithium ions move between particles, causing gaps and gas generation. Increased gas causes swelling inside the battery. This leads to separator damage, electrolyte leakage, and in severe cases, battery fires. It is also a main cause of reduced battery life. In contrast, single-particle cathode materials are 4㎛ in size, made by forming nickel, cobalt, manganese, and other metals into a single particle shape. They have higher durability and less gas generation, improving stability and extending battery life compared to conventional materials.

POSCO Future M conducts rigorous quality control for cathode material production. Despite many advantages, single-particle cathode materials have many challenging aspects in the process. Choi Wook, Head of Cathode Material Production at POSCO Future M Gwangyang, said, "Single-particle cathode materials have larger particles, reducing unnecessary space and increasing energy density," but added, "(Because) the particle size is large, the surface area in contact with the outside is also large, and lithium reacts well with hydrogen and oxygen inside the cathode material, producing defective products. The heating temperature must be raised by more than 100 degrees compared to conventional processes," revealing the difficulties in quality control. "Process environments such as temperature and humidity must be controlled more meticulously. There are challenging aspects in quality management," he explained.

Automated product warehouse inside POSCO Future M's anode material plant in Gwangyang. Photo by POSCO Future M

POSCO Future M conducts rigorous quality control for cathode material production. Despite many advantages, single-particle cathode materials have many challenging aspects in the process. Choi Wook, Head of Cathode Material Production at POSCO Future M Gwangyang, said, "Single-particle cathode materials have larger particles, reducing unnecessary space and increasing energy density," but added, "(Because) the particle size is large, the surface area in contact with the outside is also large, and lithium reacts well with hydrogen and oxygen inside the cathode material, producing defective products. The heating temperature must be raised by more than 100 degrees compared to conventional processes," revealing the difficulties in quality control. "Process environments such as temperature and humidity must be controlled more meticulously. There are challenging aspects in quality management," he said.

Cathode Material Process Similar to Cheese Bread... Rigorous Quality Control with 2,000 CCTVs and Automated Warehouse

At POSCO, the cathode material process is often compared to 'cheese bread.' When the raw ingredients for bread, 'flour' (lithium, nickel, manganese, cobalt, etc.), are added, the 'dough' (mixing process) is prepared first. This dough is baked at an appropriate temperature and time, called 'calcination.' Afterward, post-processing steps such as heat treatment (coating the surface at high temperature to enhance product stability) and blending (mixing products to match packaging units) are performed before the final product is released to the market. POSCO Future M's cathode material process aims to minimize 'foreign substances' that create defective products in the 'cheese bread' (cathode material).

Son Dong-gi said, "To improve quality control and productivity, we automated most processes using the manufacturing execution system (MES) and robots applied at POSCO steelworks," adding, "We installed 2,000 closed-circuit televisions (CCTVs) inside the factory. If any equipment malfunction or abnormal behavior is detected, a red light automatically turns on in the control room to alert operators."

They also established a system for rapid inspection of samples within the process. Choi said, "We built a pipeline connecting each process line up to 1 km away to the quality analysis room," explaining, "By applying pressure on one side, samples weighing about 1 kg are transported by air to the analysis room. This is POSCO Future M's unique 'air shooting' technology." Samples are categorized by floor using red, yellow, and blue colors and analyzed in real-time for particle size, component ratios, and moisture content.

POSCO Future M's technological prowess also shines in the 'automated logistics warehouse' where finished cathode materials and raw materials are stored. The warehouse, 20 meters high with a floor area of 5,340㎡ (about 1,615 pyeong), can store up to 12,000 tons of cathode materials and raw materials. Cathode materials packed in 'ton bags' weighing up to 1 ton each move up and down along steel structures and are transported to processing and shipping stages by 12 automated guided vehicles (AGVs). Choi said, "To prepare for accidents such as ton bags tearing, six temperature and humidity control devices operate in the warehouse," adding, "The Gwangyang plant is divided into four stages, and each stage operates such automated warehouses."

A view of POSCO Group's secondary battery materials complex in Yulchon Industrial Complex, Gwangyang-si, Jeollanam-do. Photo by POSCO Future M

South Korea's Leading Cathode Material Ecosystem Factory Becomes a 'Model Factory'

POSCO Future M's Gwangyang cathode material factory can produce 90,000 tons of cathode materials annually. It is the world's largest single-factory scale, enough to produce 1 million electric vehicles. It was completed in four stages starting from July 2019. Production capacity was increased step-by-step, and the product lineup was expanded.

Stages 1 and 2 are collectively called Plant 1, producing 30,000 tons of cathode materials. Stage 1 operates two lines, each producing 2,500 tons. Stage 2 increased production capacity to 5,000 tons per line and expanded to five lines. It mainly produces NCM (nickel-cobalt-manganese) cathode materials with nickel content over 65%, supplying LG Energy Solution's plant in Poland and others.

Stages 3 and 4, collectively called Plant 2, were completed in November last year. Production capacity doubled compared to Plant 1, producing a total of 60,000 tons of cathode materials. Each line can produce 10,000 tons, and the product range has diversified to include single-particle cathode materials, NCMA (NCM with aluminum added), and NCA (nickel-cobalt-aluminum) cathode materials. Plant 2's products are exported to the United States, with GM and LG Energy Solution as customers.

Son Dong-gi said, "The U.S. Inflation Reduction Act stipulates that battery cathode materials produced in FTA partner countries can receive subsidies, creating an environment to expand cathode material business domestically," adding, "(The Gwangyang cathode material factory) has established an ecosystem from raw materials like lithium and nickel to precursors (cathode material raw materials), battery recycling, and cathode materials, and is being used as a 'model factory' to expand global mass production capacity."