Lithium Batteries "Chronic Illness": Cumulative Safety Risks During Cyclic Aging

Lithium Batteries "Chronic Illness": Cumulative Safety Risks During Cyclic Aging

As the core component of energy storage systems, lithium batteries face safety 

risks during cyclic aging that act like a "chronic illness," gradually emerging over time 

and potentially leading to thermal runaway or even explosions. This accumulation of 

hidden dangers not only threatens user safety but also becomes a critical bottleneck 

constraining the sustainable development of the industry. This article analyzes the material 

degradation mechanisms, evolutionary paths of safety hazards, and countermeasures in 

three aspects.

I. Microscopic Mechanisms of Cyclic Aging: From Lithium Plating to Structural Fatigue

During charge-discharge cycles, the insertion and extraction of lithium ions between 

positive and negative electrodes cause irreversible structural damage to battery materials. 

Lithium plating is a typical issue: rapid charging leads to lithium metal dendrite formation 

on the anode surface, which may pierce the separator and cause internal short circuits. Studies 

show that after 500 cycles, the internal resistance of a battery pack in an energy storage power 

station increases by over 30%, significantly raising the probability of thermal runaway. Additionally, 

structural fatigue of cathode materials cannot be ignored. High-nickel ternary materials 

(e.g., NCM811) experience particle cracking due to volume expansion during long-term cycling, 

releasing oxygen and accelerating electrolyte decomposition to initiate a chain exothermic reaction.

II. Dynamic Erosion of Safety Margins: From BMS Blind Spots to System Failure

Battery Management Systems (BMS) can monitor voltage and temperature in real time but struggle to 

detect microscale changes caused by cyclic aging. For example, continuous thickening of the solid electrolyte 

interphase (SEI) layer on electrodes masks the true State of Charge (SOC), increasing overcharge risks; 

meanwhile, internal micro-shorts may go undetected due to insufficient sensor sensitivity. More critically, 

aged batteries exhibit reduced thermal stability thresholds – the critical temperature triggering thermal 

runaway drops from ~180°C for new batteries to ~120°C after 1,000 cycles, silently breaching original safety 

design margins.

III. "Rebirth Challenges" of Second-Life Applications: Standardization Gaps and Technical Dilemmas

Second-life utilization of decommissioning batteries is considered a key resource recycling strategy, 

but aging-related safety risks create major challenges. Degraded cell consistency sharply increases safety 

hazards in repurposed battery packs: experiments show that mixing cells with different cycle histories raises 

local over-discharge probabilities by 4 times. Furthermore, existing safety standards mainly apply to new 

batteries, lacking testing metrics for aged conditions. While Toshiba's SCRM (Self-Healing Reactive Material) 

technology can suppress lithium plating by 85%, its high cost makes large-scale adoption impractical for 

low-value batteries.

IV. Solutions: From Material Innovation to Full-Life Cycle Management

Addressing cyclic aging risks requires multi-dimensional technological innovation:

1. Material Level: Develop single-crystal high-nickel cathodes and silicon-carbon composite anodes to 

reduce volume expansion; adopt solid-state electrolytes to inhibit dendrite growth.

2. System Level: Implement AI-driven aging prediction models, such as CATL's "Early Warning Black Box," 

which uses neural networks to identify fault signals 300 hours in advance with 92% accuracy.

3. Management Level: Establish battery "health fingerprint" databases using block chain for full-life

cycle traceability; promote centralized recycling models to reduce risks associated with retaining aged 

batteries in energy storage systems.

Conclusion

Safety risks from cyclic aging represent a critical hurdle for lithium battery technology advancement. Only through 

coordinated innovation in materials, systems, and management – building a full-chain protection system covering 

"production-usage-recycling" – can this "chronic illness" be overcome, driving the energy storage industry toward 

higher safety standards. In the future, with the maturation of solid-state batteries and intelligent BMS, lithium batteries 

may truly achieve the ideal state of "aging without decline, safe in use."