什么是钠电池的低温性能测试？

What is the low-temperature performance test for sodium-ion batteries?

低温性能测试评估极寒环境容量、放电平台表现，设置 0℃、-10℃、-20℃、-40℃多梯度低温仓，电芯恒温静置 4 小时后 0.2C 标准放电，对比常温 25℃容量保留率。低温下电解液粘度急剧升高，钠离子迁移速率大幅降低，内阻飙升，放电容量同步衰减。行业优秀钠电池 - 20℃容量保持 85% 以上，优于同规格锂电池；普通普鲁士蓝体系 - 20℃仅 70% 左右。测试同时记录低温放电电压压降，电压跌落严重代表极化过大，低温动力输出弱。北方户外储能、冷链设备、极地设备电芯必须全套低温测试，低温性能差产品冬季续航大幅缩水，无法正常稳定供电。

Low-temperature performance test evaluates capacity and discharge platforms under frigid conditions, adopting multi-gradient chambers at 0℃, -10℃, -20℃, -40℃. Hold cells at constant low temperature for 4 hours then discharge at standard 0.2C, compare capacity retention against 25℃ room-temperature data. Electrolyte viscosity surges at low temperature, sodium ion migration slows sharply and internal resistance rises with synchronous capacity fading. High-quality sodium batteries retain over 85% capacity at -20℃, superior to equivalent lithium batteries; ordinary Prussian blue systems only maintain about 70%. Record voltage drop during low-temperature discharge; severe voltage drop indicates excessive polarization and weak low-temperature power output. Cells for northern outdoor storage, cold-chain and polar equipment require full low-temperature testing. Products with poor low-temperature performance suffer drastically shortened winter endurance and fail stable power supply.