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普克特定律

1897

Wilhelm Peukert

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一个经验公式，用于描述电池的可用容量如何随着放电率的增加而减少。该定律表示为 [latex]C_p = I^k t[/latex]，其中 [latex]C_p[/latex] 是一安培放电速率下的容量，[latex]I[/latex] 是放电电流，[latex]t[/latex] 是放电时间，[latex]k[/latex] 是针对电池类型的普克特常数。它量化了高负载时的低效率。

Peukert’s law provides a more accurate picture of battery capacity than the simple amp-hour rating, which is typically specified at a low, constant discharge rate. The law accounts for the fact that at high discharge rates, the battery becomes less efficient. This inefficiency stems from several factors. Firstly, the internal resistance of the battery causes energy to be lost as heat, a loss that increases with the square of the current ([latex]P_{loss} = I^2R[/latex]). This wasted energy is unavailable to the load.

Secondly, the electrochemical processes within the battery have finite speeds. At high discharge rates, the chemical reactions cannot keep pace, and the diffusion of ions within the electrolyte becomes a bottleneck. This leads to a depletion of reactants near the electrodes’ surfaces, causing the voltage to drop prematurely and cutting off the discharge before all the active material has been utilized. The unused material means the effective capacity delivered is lower.

The Peukert constant, [latex]k[/latex], is determined empirically and reflects how much a battery is affected by high discharge rates. A value of [latex]k[/latex] close to 1 indicates an ideal battery that is not significantly affected by the discharge rate. Lead-acid batteries have a relatively high [latex]k[/latex] (typically 1.1 to 1.3), while modern lithium-ion batteries have a [latex]k[/latex] much closer to 1 (e.g., 1.05), indicating their superior performance under heavy loads.

电池, 电气工程, 电阻, 活力, 锂, 工艺优化, 质量管理, 可再生能源, 可持续发展实践

UNESCO Nomenclature: 3305

– Electrical engineering

类型

抽象系统

中断

实质性

使用方法

广泛使用

前体

Ohm’s Law and the concept of internal resistance
开发实用的高容量电池，例如铅酸电池
电力牵引和照明等工业应用对可预测性能的需求
电池放电曲线的实验工作

应用

电池管理系统（BMS）用于精确的充电状态估算
为离网太阳能系统设计和确定电池组的尺寸
预测不同驾驶条件下电动汽车的续航里程
不间断电源（UPS）中电池性能的建模

专利：

潜在的创新想法

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Related to: Peukert’s law, battery capacity, discharge rate, state of charge, battery management system, empirical formula, C-rate, internal resistance.