This chapter addresses cell-level and chemistry-level standards for stationary energy storage systems (ESS). Using the simulator's eleven chemistry ENUMs (LFP, NMC, LCO, LTO, NIMH, LEAD_ACID, FLOW_BATTERY, VANADIUM_REDOX, SODIUM_ION, SOLID_STATE, NICKEL_HYDROGEN) as a baseline, this chapter defines the electrochemical characteristics, safety behavior, and life models for each chemistry, and establishes harmonization with five core international standards: IEC 62619, IEC 62133, UL 1973, SAE J2929, and GB/T 36276. Korean operators can simultaneously satisfy global and domestic certification requirements through the cross-walk between this chapter and Korean Industrial Standard KS C 8546.
The battery cell is the smallest functional unit of an ESS and simultaneously its most dangerous element. A minor internal defect propagating from cell to module, from module to rack, and from rack to the entire system into a large-scale fire is the highest-priority risk to be intercepted under the four-axis structure of this standard. This chapter quantifies that risk at the cell level and defines the interface for safely passing those measurements to the BMS axis (Chapter 3).
Lithium iron phosphate (LFP) cells use LiFePO₄ as the cathode and graphite as the anode. Nominal voltage is 3.2 V, energy density 90–160 Wh/kg, and cycle life 3,000–6,000 cycles. The defining strength is thermal stability: the cathode crystal structure remains stable, releasing no oxygen even above 270℃, making thermal runaway significantly less likely than with NMC. This standard recommends LFP as the default chemistry for GRID_SCALE, UTILITY, RESIDENTIAL, and MICROGRID applications.
In Korea, LG Energy Solution's RESU FLEX residential LFP ESS line and SK On's SCM Pack LFP are representative products. POSCO Future M began mass production of LFP cathode material in 2024, and EcoPro BM has announced LFP production starting in 2025. The Korea Electronics Technology Institute (KETI) developed an LFP cell life-prediction model under its 2024 ESS Battery R&D Consortium, and the Korea Institute of Energy Research (KIER) has published an LFP fire-behavior simulation model.
LFP cell testing must satisfy the following items in IEC 62619:2022: external short circuit, overcharge, forced discharge, thermal stability, crush, nail penetration, and drop. This standard further recommends a long-term self-discharge test, because while LFP's self-discharge rate is lower than NMC's, cell balance can degrade after one year or more of storage.
Nickel cobalt manganese (NMC) cells use LiNiₓCoᵧMnzO₂ (x+y+z=1) ternary oxide as the cathode. Nominal voltage is 3.6–3.7 V, energy density 150–250 Wh/kg, and cycle life 1,500–3,000 cycles. Energy density is higher than LFP, allowing more energy per unit volume, but the cathode oxygen-release temperature of 200–210℃ is lower than LFP's, giving NMC a comparatively greater thermal-runaway risk. This standard recommends NMC only for EV_BATTERY and selected high-density COMMERCIAL_INDUSTRIAL applications.
The three major Korean battery manufacturers — LG Energy Solution, Samsung SDI, and SK On — all possess world-leading NMC cell mass-production technology, holding approximately 35% of the global NMC ESS cell market in 2024. NMC safety depends heavily on cell design (separator, electrolyte, cathode crystal stabilization) and on precise BMS monitoring; accordingly, this standard imposes stricter BMS requirements on NMC ESS than on LFP ESS (see Chapter 3).
NMC cell testing must satisfy IEC 62619, UL 1973, and SAE J2929. SAE J2929 defines tests for EV traction batteries; for second-life NMC use, the SAE J2929 test history must be included in the manifest. KETI has developed life-prediction models for NMC variants by nickel content (NMC 622, NMC 811, NMC 9½½), quantifying the trade-off that higher nickel content reduces cycle life and thermal stability.
Lithium cobalt oxide (LCO) cells are predominantly used in consumer and portable applications and are seeing declining use in stationary ESS. This standard permits LCO only for small UPS applications under 1 kWh. Lithium titanate oxide (LTO) cells use Li₄Ti₅O₁₂ as the anode and operate at a lower nominal voltage of 2.3 V; cycle life is 15,000–20,000, with capability for rapid charge/discharge and low-temperature operation down to -40℃, making LTO well-suited to frequency-regulation GRID_SCALE applications. In Korea, a portion of KEPCO's 376 MW frequency-regulation ESS is LTO-based.
Next-generation chemistries include flow batteries (FLOW_BATTERY, VANADIUM_REDOX), sodium-ion (SODIUM_ION), solid-state (SOLID_STATE), and nickel-hydrogen (NICKEL_HYDROGEN). Flow batteries are favorable for long-duration storage of eight hours or more; with the electrolyte physically separated from the cell stack, they are intrinsically immune to thermal runaway. KIER plans a 200 kW vanadium flow battery demonstration in 2025, and offers a roadmap to grow non-lithium ESS share to 15% by 2030, modeled on Japan's NEDO program.
Sodium-ion (Na-ion) cells are emerging as an alternative that sidesteps the geopolitical risk of lithium supply. China's CATL began mass production in 2024; in Korea, KETI is developing an LFP-equivalent test matrix for SODIUM_ION cells. Solid-state cells replace the liquid electrolyte with a solid one, fundamentally eliminating thermal-runaway risk, but mass-production technology is still maturing. Samsung SDI targets pilot production of solid-state ESS cells in 2027.
| Chemistry | Energy Density | Cycle Life | Core Standards | Recommended Applications |
|---|---|---|---|---|
| LFP | 90–160 Wh/kg | 3,000–6,000 | IEC 62619, UL 1973 | GRID_SCALE, UTILITY, RESIDENTIAL |
| NMC | 150–250 Wh/kg | 1,500–3,000 | IEC 62619, UL 1973, SAE J2929 | EV_BATTERY, COMMERCIAL_INDUSTRIAL |
| LCO | 150–200 Wh/kg | 500–1,000 | IEC 62133 | Small UPS |
| LTO | 60–80 Wh/kg | 15,000–20,000 | IEC 62619, UL 1973 | Frequency-regulation GRID_SCALE |
| FLOW_BATTERY | 20–30 Wh/L | 10,000+ | IEC 62932 series | Long-duration GRID_SCALE |
| SODIUM_ION | 90–150 Wh/kg | 3,000–5,000 | IEC 62619 (forthcoming) | RESIDENTIAL, UTILITY |
Beyond these five core standards, China's GB/T 36276-2018 is mandatory for the Chinese market, and Japan's JIS C 8715-2 applies to the Japanese market. This standard uses IEC 62619 as a baseline and maps additional requirements from each national standard via cross-walk. Korean operators can therefore satisfy multiple national certifications with the same test results.
Cell safety and life are determined by the specifications of five components: cathode, anode, separator, electrolyte, and current collector. This standard defines minimum specifications for each component by chemistry.
For cathodes, LFP is recommended at particle sizes of 1–5 μm, BET specific surface area of 10–20 m²/g, and tap density of 1.2–1.8 g/cm³. NMC is recommended at particle sizes of 8–15 μm, BET specific surface area of 0.3–0.5 m²/g, and residual lithium (LiOH plus Li₂CO₃) below 1,000 ppm. Graphite is the dominant anode material, with artificial graphite outperforming natural graphite in cycle life. Korea's POSCO Future M and Japan's Mitsubishi Chemical lead global production of artificial graphite.
Separators are typically polyethylene (PE) single-layer or PE/PP multi-layer structures, recommended at 12–25 μm thickness, puncture strength of 300 gf or greater, and shutdown temperature of 130–140℃. SK Innovation ranks among the global top three separator producers. Electrolyte uses LiPF₆ dissolved in EC/DMC/EMC, common to LFP and NMC; additive type and concentration (VC, FEC) decisively influence cell life. Soulbrain and Dongwha Enterprise anchor the Korean electrolyte supply chain.
IEC 62619:2022 defines cell test procedures in seven steps: external short circuit, overcharge, forced discharge, thermal stability (30 minutes at 130℃), crush (13 kN), nail penetration (Ø3 mm nail at 80 mm/s), and drop. Each test uses absence of "explosion, fire, or leakage" (gas venting through designed vents is permitted) as the pass criterion.
UL 1973:2022 defines additional system-level tests, verifying the safety of cell-qualified modules and racks after they are integrated into a system. This standard defines a four-tier test flow — cell, module, rack, system — in which the result of each tier automatically determines the test conditions for the next. Simulator Panel 1 visualizes this four-tier flow alongside the alignment with Korean KESCO pre-use inspection criteria.
Korea holds approximately 40% of global ESS cell shipments in 2024 through its three major manufacturers (LG Energy Solution, Samsung SDI, SK On). In the cathode-material supply chain, POSCO Future M, EcoPro BM, LG Chem, and L&F rank in the global top ten. SK Innovation leads separators, Soulbrain and Dongwha Enterprise lead electrolyte, and POSCO Future M and BTR Korea lead anode materials. Korea is the only country with global competitiveness across the full battery value chain.
This industrial position reinforces the meaning of Korean origination for this standard. This standard serves as infrastructure for Korea to position itself not merely as a product exporter but as an "integrated supplier of technology, standards, and verification." MOTIE's ESS Industry Development Strategy (October 2023) targets $10 billion in ESS exports by 2030, and this standard is a non-tariff-barrier (NTB) response tool for that target.
KETI has developed LFP and NMC cell life-prediction models, thermal-runaway behavior simulation, and fast-charge degradation models through the ESS Battery R&D Consortium. KIER leads demonstration projects for flow batteries, sodium-ion, and solid-state next-generation chemistries. KEMRI is responsible for government R&D budget allocation and demonstration project evaluation; the cell test procedures in this standard align with KEMRI's demonstration-evaluation manual.
The state-of-health (SOH) of a cell, typically defined as "current full-charge capacity divided by initial rated capacity," is a key indicator of both ESS economics and safety. End-of-life (EOL) for an ESS is conventionally set at 80% SOH. KETI recommends three SOH prediction models for this standard:
The BMS standard in Chapter 3 mandates that at least one of these three models be deployed in every BMS. The Anchored tier additionally requires a maximum 12-month model-retraining cycle and validation that prediction error is within 5% MAE. The 2023 revision of KS C 8546 aligns its SOH prediction accuracy requirements with those of this standard.
The recommended workflow for Korean operators to leverage this chapter is as follows. First, use Simulator Panel 1 to select an application scenario and chemistry, generating a recommended test matrix. Second, commission testing through a KESCO-accredited laboratory (e.g., KTR, KTC). Third, integrate test results into the manifest and attach a Sigstore DSSE signature. Fourth, submit the KESCO pre-use inspection and this standard's evidence package simultaneously.
The advantage of this workflow is the multi-use leverage of a single test result. Because cross-walks are designed so that the same IEC 62619 test data simultaneously satisfies UL 1973, SAE J2929, GB/T 36276, KS C 8546, and JIS C 8715-2, operators can substantially reduce test cost and time. The MOTIE target of "$10 billion in ESS exports by 2030" is unattainable without this efficiency.
This standard also provides standard evidence templates for partnership with insurers and financial institutions. The Korea Fire Protection Association (KFPA) and the General Insurance Association of Korea are reviewing recognition of the Anchored-tier manifest as base evidence for ESS insurance underwriting. This is a market mechanism that simultaneously reduces premiums and incentivizes safety investment.
Normal cell operation is guaranteed only within a narrow range of electrical and thermal conditions. Operation outside the safe operating area (SOA) can cause irreversible damage or thermal runaway. This standard defines the SOA per chemistry. LFP's SOA is: charge voltage at or below 3.65 V, discharge voltage at or above 2.0 V, charging temperature 0–45℃, discharging temperature -20–60℃, maximum charge current 1C, maximum discharge current 3C. NMC has a narrower SOA: charge voltage at or below 4.2 V, discharge voltage at or above 2.5 V, charging temperature 0–45℃, discharging temperature -20–55℃, maximum charge current 0.5C, maximum discharge current 2C.
Abnormal operation falls into four categories. Overcharge releases oxygen at the cathode and causes lithium plating on the anode, increasing the short-circuit risk. Overdischarge dissolves the copper current collector, which can pierce the separator. Overcurrent causes rapid internal temperature rise that may trigger thermal runaway. Thermal abnormality leads to electrolyte decomposition and degradation of the solid electrolyte interphase (SEI) layer.
Cell safety design comprises five defensive layers, all of which must be satisfied for cell-level conformance. (1) Material selection — cathode crystal stability, separator shutdown temperature, electrolyte flash point, and anode volume expansion determine the fundamental fire and thermal-runaway risk. (2) Cell design — electrode thicknesses, separator thickness, electrolyte fill volume, safety vent design, terminal placement, and case material (pouch, prismatic, cylindrical) determine the thermal and gas-escape paths during an incident. (3) Manufacturing quality control — slurry dispersion, coating thickness uniformity, separator tensile strength, foreign-particle exclusion, electrolyte fill precision, and formation charge profile determine cell reliability. (4) Shipment testing — open-circuit voltage, self-discharge rate, direct-current internal resistance (DCIR), and coulombic efficiency screen out defective cells before deployment. (5) Field monitoring — the BMS observes voltage, temperature, and current at the cell level in real time, detecting anomalies immediately.
This standard requires that all five layers be satisfied. The BMS standard in Chapter 3 specifies that cell-level monitoring period must be no greater than 100 ms.
Of the 23 ESS fires in Korea between 2017 and 2019, cell-level root causes were directly implicated in eight cases. The eight cell-related defect types are: separator damage (4 cases), cathode crystal instability (2 cases, NMC with excessive nickel), cell assembly defects (1 case), and missed shipment testing (1 case). All eight occurred in NMC cells rather than LFP. This is the empirical basis for this standard's recommendation that LFP be the default chemistry for GRID_SCALE, UTILITY, and RESIDENTIAL applications.
KETI synthesized the cell-debris analyses from the 23 fires into the Korean Cell Safety Design Guideline published in 2020. The guideline recommends separator thickness of 16 μm or greater, puncture strength of 350 gf or greater, and shutdown temperature of 130℃ or less, aligning with the recommendations in this standard. KETI also recommends mandatory 7-day self-discharge measurement during shipment testing as the most effective method for detecting cells with latent internal short-circuit defects.
The European Union enacted Regulation (EU) 2023/1542 (the Battery Regulation) in July 2023, requiring a Digital Battery Passport (DBP) for all industrial and EV batteries placed on the EU market from February 2027. The DBP captures chemistry, raw-material origin, carbon footprint, recyclable share, and safety test history in a digital format. This standard's manifest is designed for full compatibility with the DBP format.
MOTIE's 2024 Spent Battery Industry Activation Plan introduces a Korean digital battery passport, with KETI managing the pilot program toward full deployment in 2025. This standard's manifest provides cross-walks that simultaneously satisfy the Korean DBP, the EU DBP, and the UN/CEFACT Battery Passport standard. Korean operators can therefore reach the Korean, EU, and global markets with the same dataset.
The core value of the digital passport is traceability. When a single cell catches fire, it must be possible to trace exactly when, where, and from what raw materials it was made, which tests it passed, and what operating history it experienced. The Anchored-tier manifest binds the cell's lifecycle data — from shipment through retirement — into a Sigstore DSSE envelope, preserving it in tamper-evident form.
Cells age progressively in use, with SOH declining as cycle count increases. The primary aging mechanisms are: SEI layer growth and resulting lithium loss; micro-cracking of cathode crystals; exfoliation of graphite anode layers; electrolyte decomposition and gas generation; and rising contact resistance between current collectors and active materials. The BMS standard in Chapter 3 recommends an SOH model that quantitatively tracks all five mechanisms.
Cells reaching 80% SOH are deemed to have ended their primary stationary-ESS life, but this standard actively recommends second-life use. Batteries recovered from EVs with 70–80% SOH are well-suited to residential and small commercial second-life ESS. MOTIE's 2024 Spent Battery Industry Activation Plan establishes Korea's second-life ecosystem, for which this standard is core infrastructure. Cells falling below 60% SOH enter third-life or recycling. Korean firms SungEel HiTech and EcoPro CnG are among the top ten global battery recyclers, operating hydrometallurgical refining with recovery rates above 95% for lithium, nickel, cobalt, and manganese.
This chapter has defined the first of the four ESS axes, "chemistry and cell." The three core messages are: (1) accurate understanding of each chemistry's characteristics is required for sound application selection; (2) cell test standards center on IEC 62619 as the baseline, with UL 1973, SAE J2929, GB/T 36276, and KS C 8546 added by application; and (3) Korea's full-value-chain industrial competitiveness justifies the Korean origination of this standard.
Chapter 3 covers BMS and PCS. Even safe cells are useless if the BMS cannot accurately monitor voltage and temperature, and a precise BMS threatens the grid if the PCS violates IEEE 1547 anti-islanding requirements. The cell test results defined in this chapter feed the BMS in Chapter 3, which through the BMS-PCS communication interface determines PCS operating limits. In the spirit of "Hongik Ingan," this standard pursues safety and reliability simultaneously across all chemistries, all applications, and all scales.
弘益人間 (Hongik Ingan) — Benefit All Humanity