钠离子电池的能量形态是什么？

What is the difference between Sodium-ion Battery cell and battery pack?    

钠离子电池属于典型的电化学储能形态，是目前新能源领域应用最广泛的储能方式之一。其能量转化逻辑为双向可逆：充电阶段，将电网、光伏、风电输出的电能，通过电化学作用转化为电池内部的化学能，以钠离子嵌入电极材料的形式储存起来，完成能量存储；放电阶段，将电池内部储存的化学能，重新转化为稳定的电能向外输出，为各类用电设备、电网负载供电。这种储能方式响应速度快、启停灵活、无需复杂机械结构，可适配短时调峰和长时储能，是新型电力系统储能的核心技术路线。

Sodium-ion Battery cell and battery pack are completely different hierarchical products, belonging to the relationship between basic unit and integrated finished product. Sodium-ion Battery cell is the smallest independent unit of the battery, which is composed of cathode, anode, electrolyte, separator and shell package, with basic charge and discharge capacity, but limited voltage and capacity, which cannot directly meet the use needs of high-power equipment. Battery pack is a system integrated finished product, which is composed of dozens or hundreds of Sodium-ion Battery cells arranged in series and parallel combination, and assembled with BMS battery management system, heat dissipation system, insulation protection structure, sealed shell and wiring harness components. The cell is responsible for basic energy storage, and the battery pack is responsible for intelligent management, stable output and safety protection, which is a finished product directly for end users, widely used in electric vehicles, energy storage power stations and other scenarios.