As the core device for energy storage, the charging and discharging efficiency of an energy storage battery pack is directly constrained by ambient temperature. Extreme temperature environments negatively impact the performance of energy storage battery packs in multiple dimensions by altering the kinetics of internal electrochemical reactions, mass transfer efficiency, and material stability. This impact manifests different failure mechanisms in low-temperature and high-temperature scenarios.
In low-temperature environments, the electrolyte in an energy storage battery pack exhibits a significant increase in viscosity due to the decreasing temperature. This leads to increased resistance to lithium ion migration within the electrolyte, much like a liquid becoming viscous at low temperatures, making ion movement difficult. This change in physical properties directly weakens the battery's charging and discharging capabilities: during charging, lithium ions struggle to quickly embed into the negative electrode material, resulting in decreased charging efficiency; during discharging, the rate of lithium ion insertion and extraction from the negative electrode slows down, significantly reducing the battery's usable capacity. Low temperatures also slow down the reaction rate at the electrode interface, sluggishing the insertion and extraction processes of lithium ions in the electrode material, further exacerbating battery performance degradation. Even more seriously, during low-temperature charging, lithium ions may precipitate directly as metallic lithium due to their inability to embed into the negative electrode in time, forming lithium dendrites. These dendrites can pierce the battery separator, causing internal short circuits and triggering thermal runaway, posing a direct threat to battery safety.
The destructive impact of high temperatures on energy storage battery packs is mainly reflected in the accelerated decomposition and side reactions of internal battery materials. High temperatures cause the electrolyte to oxidize and decompose, generating gas and causing the battery to expand, even leading to leakage or explosion. Simultaneously, high temperatures accelerate the continuous growth and decomposition of the solid electrolyte interphase (SEI) film. This process continuously consumes active lithium and electrolyte, leading to a continuous increase in internal resistance and a permanent decrease in capacity. High temperatures also exacerbate the structural degradation of battery materials; the crystal structure of the positive and negative electrode materials may undergo irreversible changes due to thermal stress, further weakening the battery's charge and discharge performance. More dangerously, high temperatures act as a "catalyst" for thermal runaway, significantly lowering the trigger temperature for thermal runaway. Once the battery begins to generate heat due to abuse or internal defects, the high-temperature environment can rapidly push the battery to an irreversible thermal runaway state, leading to fire or explosion.
The impact of extreme temperatures on energy storage battery packs is also reflected in the degradation of cycle life. In low-temperature environments, each charge-discharge cycle causes irreversible damage to the battery structure due to lithium dendrite formation and microcrack propagation in the electrode material, leading to gradual capacity decay. In high-temperature environments, the battery's cycle life is accelerated by mechanisms such as electrolyte decomposition, SEI film thickening, and material structure degradation. This lifespan degradation not only increases battery replacement costs but also reduces the overall economic efficiency of the energy storage system.
To address the challenges of extreme temperatures, energy storage battery packs require advanced thermal management systems. In low-temperature scenarios, heating technologies such as PTC heating films and liquid thermal systems can maintain the battery's operating temperature, while thermal insulation materials are used to reduce heat loss. In high-temperature scenarios, liquid cooling and air cooling technologies are needed to promptly dissipate heat and prevent overheating. These thermal management measures maintain the battery's operating temperature within its optimal range through precise temperature control, thereby ensuring its charge-discharge efficiency and safety.
Extreme temperature environments have a significant negative impact on the charge-discharge efficiency of energy storage battery packs, and this impact manifests through different physicochemical mechanisms in low-temperature and high-temperature scenarios. Low temperatures mainly lead to hindered ion migration, delayed electrode reactions, and lithium dendrite formation, while high temperatures accelerate material decomposition, side reactions, and structural degradation.
