In the context of resource scarcity and environmental pollution, I have observed that China is actively promoting carbon peak and carbon neutrality, which has significantly accelerated the development of the new energy industry. The energy storage cell industry is experiencing tremendous growth opportunities. As a critical technology for power systems, the safety, reliability, and economic viability of energy storage cells directly influence renewable energy integration and grid stability. Through my research on relevant policies, regulations, and standards, I have analyzed the development trends and current standardization efforts in the energy storage cell sector. My work aims to explore directions for improving energy storage cell testing standards, providing both theoretical and practical guidance for the industry’s healthy and sustainable development.
1. Research Background
Energy storage cells serve as pivotal devices in the energy storage domain, enabling the mutual conversion and storage between electrical energy and chemical energy (or physical energy, kinetic energy). They play an indispensable role in improving energy utilization efficiency, promoting clean energy applications, and facilitating energy transition. In recent years, the share of electrochemical energy storage in the global energy storage market has risen sharply. Among various technologies, lithium-ion energy storage cells dominate the market due to their excellent comprehensive performance, while flow batteries and sodium-sulfur batteries also play unique roles in specific applications. According to the China Energy Storage Cell Industry Development White Paper (2025), global energy storage cell shipments reached 369.8 GWh in 2024, a year-on-year increase of 64.9%, with Chinese enterprises accounting for 93.5% of shipments. Unlike conventional consumer batteries, the core function of energy storage cells is to store large amounts of energy over extended periods and undergo frequent, high-efficiency charge-discharge cycles. This capability supports diverse applications such as grid peak shaving, renewable energy integration, and emergency backup power. However, issues related to safety, cycle life, reliability, and lifecycle cost remain critical bottlenecks limiting large-scale deployment. Therefore, establishing a scientific and rigorous energy storage cell testing standard system is of great significance for ensuring product safety, improving performance quality, guiding technological advancement, reducing application costs, and promoting fair market competition.
2. Trends in the Energy Storage Cell Industry
2.1 Rapid Market Expansion
The energy storage industry is booming under the dual drive of policy incentives and market demand. The energy transition and increasing penetration of renewable sources such as wind and solar have created strong demand for energy storage. Electrochemical energy storage, particularly lithium-ion energy storage cells, has become key to stabilizing grid operation due to its fast response, high efficiency, and flexible deployment. Meanwhile, continuous technological progress and large-scale production have significantly reduced costs, greatly improving the economic viability of energy storage projects. Furthermore, the application scenarios for energy storage are expanding—from traditional power system ancillary services to commercial and industrial storage on the user side, residential storage, communication base stations, data centers, and electric vehicle charging infrastructure. These developments are propelling the energy storage cell industry into a period of high-speed growth.
2.2 Diversification of Technology Pathways
Energy storage cell technologies are evolving toward diversification to meet varying requirements for cost, lifespan, safety, energy density, and power characteristics across different applications. Each battery type has unique advantages and limitations. Lithium-ion energy storage cells, with high energy density, long cycle life, mature industrial chains, and low cost, have captured a large market share. However, their inherent safety risks (e.g., thermal runaway) and dependence on critical resources (e.g., lithium, cobalt) remain concerns. Sodium-ion energy storage cells offer abundant sodium resources, low cost potential, good low-temperature performance, and higher safety, making them a complementary or alternative solution to lithium-ion in cost-sensitive or low-energy-density applications. However, their energy density and cycle life are still inferior to mature lithium technology, and their industrial chain is in early development. Flow batteries feature high safety, long cycle life, independent design of power and capacity, and easy recyclability, making them suitable for long-duration and large-scale energy storage; their drawbacks include low energy density, high system complexity, and high initial investment. Lead-acid batteries are mature, low-cost, have well-established recycling systems, and excellent high-rate discharge performance, but suffer from low energy density and short cycle life. Lead-carbon batteries, by introducing carbon materials into the negative electrode, significantly improve charge acceptance and extend cycle life, but at increased cost. Additionally, zinc-based batteries, sodium-sulfur batteries, and other technologies are developing in specific niches or are in R&D and demonstration stages. Together, these technologies constitute an increasingly rich energy storage landscape, driving the industry to meet broader demands.
To systematically compare these technologies, I have compiled a table summarizing key characteristics.
| Technology | Energy Density (Wh/kg) | Cycle Life (cycles) | Safety | Cost ($/kWh) | Typical Applications |
|---|---|---|---|---|---|
| Lithium-ion (LFP) | 140–180 | 4,000–10,000 | Moderate (thermal risk) | 100–150 | Grid storage, EVs, residential |
| Lithium-ion (NMC) | 200–260 | 2,000–5,000 | Lower than LFP | 120–180 | Automotive, portable |
| Sodium-ion | 100–160 | 2,000–4,000 | Higher than Li-ion | 80–120 | Grid storage, low-cost storage |
| Vanadium Redox Flow | 15–30 (system) | >15,000 | Very high (non-flammable) | 300–500 | Long-duration, large-scale grid |
| Lead-carbon | 30–50 | 2,000–4,000 | High (stable) | 80–150 | UPS, small-scale storage |
| Lead-acid (AGM) | 30–40 | 500–1,200 | High | 50–100 | Backup, off-grid |
| Zinc-bromine flow | 30–60 | >2,000 | High | 200–400 | Medium-duration storage |
Furthermore, different application scenarios impose distinct requirements on energy storage cells. I have summarized the key performance indicators in the following table.
| Application | Key Requirements | Typical Energy Storage Cell Type |
|---|---|---|
| Grid peak shaving | Long cycle life, high round-trip efficiency, low LCOE | Lithium-ion LFP, flow batteries |
| Renewable integration | Fast response, high power capability, long duration | Lithium-ion, flow batteries |
| Residential backup | Safety, compact size, moderate cycle life | Lithium-ion LFP, lead-carbon |
| Industrial/commercial | Low CAPEX, high reliability, wide temp range | Lithium-ion, sodium-ion, lead-carbon |
| Communication base stations | Wide temperature tolerance, long standby life | Lead-carbon, lithium-ion LFP |
| Electric vehicle charging | High power output, fast charge/discharge | Lithium-ion NMC, LFP |
3. Current Status of Energy Storage Cell Testing Standards
3.1 Lithium-ion Energy Storage Cell Testing Standards
As the market leader, the testing standard system for lithium-ion energy storage cells is relatively mature and continuously improving. Internationally, IEC 62619 and IEC 62620 specify safety and performance requirements for secondary lithium cells used in industrial equipment and power energy storage systems. IEC 63056 covers safety requirements and tests for secondary lithium cells for power energy storage, including insulation, overcharge/overdischarge protection, short circuit, and reverse polarity protection. UL 1973, widely adopted in North America, evaluates safety and performance requirements for stationary storage, vehicle auxiliary power, and light electric rail vehicle batteries, covering electrical, mechanical, environmental, and functional safety aspects. At the national level in China, GB/T 36276—2023 (Lithium-ion battery for electric energy storage) specifies requirements for appearance, dimensions, mass, electrical performance, environmental adaptability, durability, and safety. GB/T 43522—2023 (Supervision guidelines for manufacturing lithium-ion batteries for electric energy storage) provides quality control guidance during production. T/CES 172—2022 (Testing specification for battery management system of energy storage station with lithium-ion batteries) details safety testing procedures. Although existing standards cover major performance and safety dimensions, ongoing updates are needed in areas such as refined test methods, aging mechanism evaluation, and system-level safety linkage testing.
3.2 Lead-acid/Lead-carbon Energy Storage Cell Testing Standards
Current testing standards for lead-acid and lead-carbon energy storage cells mainly focus on capacity retention, cycle durability, and basic safety. Internationally, IEC 61427 and IEC 60896 specify general requirements, test methods, and safety for lead-acid batteries used in renewable energy storage and stationary standby applications. In China, GB/T 22473.1—2021 (Secondary cells for energy storage — Part 1: Technical conditions for photovoltaic off-grid application) details key indicators such as capacity, consistency, sealing, charge acceptance, charge retention, water loss, and cycle life for lead-acid batteries in storage applications. Despite their advantages, lead-acid batteries have limited cycle life and suffer from sulfation under high-rate cycling, accelerating capacity degradation. Lead-carbon technology addresses these limitations by incorporating activated carbon into the negative electrode, significantly improving charge/discharge rates, specific capacity, and cycle life. For lead-carbon energy storage cells, GB/T 36280—2023 (Lead-carbon battery for electric energy storage) specifies requirements for appearance, dimensions, performance, environmental adaptability, lifespan, and safety, along with corresponding test methods.
3.3 Flow Battery Testing Standards
Testing standards for flow batteries are gradually expanding from key materials and core components to system-level performance, safety, and reliability evaluation. The IEC 62932 series specifies general requirements, performance test methods, and safety requirements for flow battery energy storage systems, serving as a key international standard. In China, GB/T 33339—2016 (Test methods for all-vanadium redox flow battery system) and GB/T 43512—2023 (Reliability evaluation method for all-vanadium redox flow battery system) provide important guidance. Additionally, NB/T 42133—2017 (Technical conditions of electrolyte for all-vanadium redox flow battery) specifies test methods for related components. For other types, standards such as NB/T 11224—2023 (Test methods for electrode of zinc-nickel flow battery) define testing procedures for electrodes, electrolytes, and separators. These standards form the foundation of the flow battery testing standard system.
To summarize the major standards across different energy storage cell types, I have created the following comprehensive table.
| Battery Type | Standard Designation | Scope | Key Test Parameters |
|---|---|---|---|
| Lithium-ion | IEC 62619 | Safety for industrial/ESS lithium cells | Overcharge, short circuit, thermal runaway, vibration |
| IEC 63056 | Safety for power ESS lithium cells | Insulation, overcharge/overdischarge, reverse polarity | |
| UL 1973 | Safety for stationary storage batteries | Electrical, mechanical, environmental, functional safety | |
| GB/T 36276—2023 | Performance & safety for power ESS Li-ion | Capacity, cycle life, high/low temp, nail penetration | |
| Lead-acid/Lead-carbon | IEC 61427 | Renewable storage lead-acid batteries | Capacity, charge acceptance, cycle life, water loss |
| GB/T 36280—2023 | Lead-carbon for power ESS | Cycle life, high-rate charge, sealing, environmental | |
| Flow (Vanadium) | IEC 62932 series | General, performance, safety for flow batteries | Energy efficiency, capacity, electrolyte crossover, fire |
| GB/T 33339—2016 | Test methods for VRFB system | Discharge capacity, voltage uniformity, self-discharge | |
| GB/T 43512—2023 | Reliability evaluation for VRFB | Fault rate, availability, maintenance intervals | |
| Flow (Zinc-based) | NB/T 11224—2023 | Electrode test for zinc-nickel flow battery | Electrode polarization, cycle stability, corrosion rate |
4. Optimization Suggestions for Energy Storage Cell Testing Standards
Given the rapid innovation in energy storage cell technologies and the increasing complexity of market demands and application scenarios, I believe that relevant standards must be continuously updated, refined, and extended based on different application contexts, the characteristics and economic benefits of various energy storage cell types, and policy directions.
4.1 Deepening and Systematization of Safety Performance Testing Standards
Safety is the bottom line for energy storage applications. Current safety-related standards for energy storage cells need substantial deepening and systematization. In my view, standard-setting organizations should develop targeted safety requirements and test methods according to different chemical systems, cell form factors, integration levels, and application scenarios. For example, they should distinguish between energy-type and power-type energy storage cells, with different safety assessment priorities. Safety standards should cover the entire lifecycle of energy storage cells, including transportation, installation, operation, maintenance, decommissioning, and recycling, with particular emphasis on quantitative evaluation of aging effects on safety performance. Additionally, I recommend strengthening system-level safety testing by improving standards for battery management systems, thermal management systems, energy management systems, and fire protection systems, including functional safety, reliability, and collaborative operations. Furthermore, it is crucial to keep pace with international developments and actively participate in international standardization activities to align domestic standards with advanced global practices, thereby addressing technological iterations and emerging safety risks.
Mathematically, the safety risk associated with an energy storage cell over its lifetime can be modeled as a function of time and operating conditions. For instance, the probability of thermal runaway may be expressed as:
$$P_{\text{TR}}(t) = 1 – e^{-\int_{0}^{t} \lambda(\tau) \, d\tau}$$
where $\lambda(\tau)$ is the failure rate at time $\tau$, which depends on factors such as temperature, state of charge (SOC), and cycle number. Standards should specify accelerated test conditions to estimate $\lambda(\tau)$ reliably.
4.2 Unification and Acceleration of Cycle Life and Reliability Testing Standards
Cycle life is a core indicator of the economic viability and durability of energy storage cells. However, I have noticed that different stakeholders currently employ varying test methods, evaluation indexes, and durations, hindering rapid technology adoption. Therefore, industry associations, together with testing institutions, should promote the establishment of a universally accepted, unified cycle life testing standard. Key parameters such as charge/discharge rate, depth of discharge (DoD), temperature, and cutoff conditions must be clearly defined, along with end-of-life criteria, to enable fair comparison across different technologies and manufacturers. In addition to average cycle life, standards should address performance consistency, early failure probability, and failure rate using statistical and probabilistic reliability testing methods. For example, the reliability function $R(t)$ can be modeled using the Weibull distribution:
$$R(t) = e^{-\left(\frac{t}{\eta}\right)^{\beta}}$$
where $\eta$ is the scale parameter (characteristic life) and $\beta$ is the shape parameter. Standards should specify $\beta$ and $\eta$ thresholds for different applications. I believe that implementing accelerated life testing based on appropriate stress models, such as the Arrhenius model for temperature acceleration:
$$AF = e^{\frac{E_a}{k} \left( \frac{1}{T_{\text{use}}} – \frac{1}{T_{\text{acc}}} \right) }$$
where $AF$ is acceleration factor, $E_a$ is activation energy, $k$ is Boltzmann constant, and $T$ is temperature in Kelvin, can significantly reduce test duration while maintaining accuracy.
4.3 Comprehensive and Scenario-Oriented Environmental Adaptability Testing Standards
Energy storage cells must operate reliably under various climatic and operational conditions. Although existing standards cover high/low temperature and humidity to some extent, I consider it necessary to further refine test requirements and methods for complex environmental factors such as salt fog (coastal areas), sand/dust (desert regions), high altitude, mold, condensation, electromagnetic compatibility, vibration, and shock. Standard-setting bodies should refer to international standards while leveraging China’s vast geographic and climatic diversity to detail environmental influencing factors. Before formulating corresponding standards, testing agencies should simulate combined stress conditions that reflect the actual application environment of energy storage cells (e.g., temperature-humidity cycling, vibration coupled with temperature) rather than single static conditions. For instance, the equivalent damage under combined thermal and mechanical cycling can be expressed using the Miner’s rule:
$$\sum_{i=1}^{k} \frac{n_i}{N_i} = 1$$
where $n_i$ is the number of cycles at stress level $i$, and $N_i$ is the number of cycles to failure at that level. Standards should define stress profiles representative of real-world scenarios to ensure validity.
5. Conclusion
In conclusion, the energy storage cell industry is at a critical juncture of rapid development and technological transformation. A comprehensive and rigorous testing standard system is the cornerstone for supporting its healthy, safe, and orderly growth. Currently, although a series of international and national standards exist for mainstream energy storage technologies, there is still room for improvement in terms of systemicity, specificity, forward-looking perspective, and international harmonization. I believe that the future development of energy storage cell testing standards should focus on the following directions: deepening and systematizing safety performance standards to cover the full lifecycle and system-level risks; refining cycle life and reliability standards to enable rapid and accurate assessment; and expanding and detailing environmental adaptability standards to ensure reliable operation under complex conditions. Continuous development, revision, and implementation of standards will effectively safeguard the quality and safety of energy storage cell products, guide technological innovation, regulate market order, and thus enable energy storage technology to play a greater role in the global energy transition.