为什么动力电池不用铅酸电池？

Core Insights - Lead-acid batteries, despite their long history and reliability, are not widely adopted as automotive power batteries due to several performance limitations compared to lithium batteries [1][9]. Performance Comparison - Energy density of lead-acid batteries is only 30-50 Wh/kg, while lithium batteries exceed 200 Wh/kg, making lead-acid batteries 3-4 times less efficient [1]. - For a 48V20Ah specification, lead-acid batteries weigh 25-30 kg, whereas lithium batteries weigh only 7-10 kg, highlighting a significant weight disadvantage [1]. - Lead-acid batteries have a cycle life of only 300-500 charge-discharge cycles under deep discharge conditions, compared to 2000-3000 cycles for lithium iron phosphate batteries and 1500-1800 cycles for ternary lithium batteries [5]. Design and Space Constraints - The low energy density of lead-acid batteries results in a volume and weight that is approximately five times that of lithium batteries, which increases overall vehicle weight and limits design flexibility [3][7]. - The high self-discharge rate of lead-acid batteries leads to rapid energy loss when vehicles are parked for extended periods, making them unsuitable for modern vehicles that require continuous power for complex electronic systems [5]. Economic and Environmental Considerations - Although lead-acid batteries have a lower initial cost, their total lifecycle cost does not present a clear advantage, and frequent replacements can lead to inconvenience [9]. - Lead-acid batteries contain lead, which conflicts with environmental goals and faces stricter regulatory pressures [9]. Specific Use Cases - Lead-acid batteries maintain a strong market position in automotive starting applications and have evolved towards EFB and AGM technologies to meet the auxiliary power needs of hybrid and new energy vehicles [9]. - In low-speed electric vehicles and industrial applications, such as electric forklifts, lead-acid batteries are favored for their cost-effectiveness and high discharge performance [9]. - Lead-acid batteries continue to hold significant importance in backup power and energy storage applications due to their reliable technology and safety features [9].