基于循环伏安法的热充电超级电容器数值研究

doi:10.12096/j.2096-4528.pgt.24058

摘要/Abstract

摘要：

目的热充电超级电容器在储能领域的应用受到电解质离子特性的限制。为探究电解质离子特性对器件电容性能和功率密度的影响，基于循环伏安法测试原理，采用多物理场数值模拟方法构建了热充电超级电容器数值模型。方法分析了离子尺寸比、离子类型对电容性能、功率密度的影响，并总结了给定温差下电极固液界面处的阳离子浓度变化规律。结果在低扫描速率下，热充电超级电容器的电流密度与比电容随离子尺寸比的增大而减小。此时，功率密度主要受离子尺寸比的影响，其随着离子尺寸比的增大而减小。而在高扫描速率下，功率密度主要受离子类型影响。结论该研究提出了电解质离子特性优化策略，对热充电超级电容器的数值建模和理论分析有重要意义。

关键词: 余热发电技术, 超级电容器, 循环伏安法, 数值模型, 离子特性, 电流密度, 功率密度, 电容性能

Abstract:

Objectives The application of thermal charging supercapacitors in energy storage is constrained by the ionic characteristics of the electrolyte. This study aims to explore the impact of electrolyte ionic characteristics on the capacitance performance and power density of the device. Based on the principle of cyclic voltammetry, a numerical model for the thermal charging supercapacitors is developed using multi-physics field numerical simulation methods. Methods The effects of ion size ratio and ion type on capacitance performance and power density are investigated separately, and the variation pattern of cation concentration at the electrode solid-liquid interface under a given temperature difference is summarized. Results The current density and specific capacitance of thermal charging supercapacitors decrease as ion size ratio increases at low scan rates. At this point, the power density is mainly affected by the ion size ratio, and it decreases as the ion size ratio increases. At high scan rates, power density is mainly affected by the ion type. Conclusions This study proposes an optimization strategy for electrolyte ionic characteristics, which is important for numerical modeling and theoretical analysis of thermal charging supercapacitors.

Key words: waste heat power generation technology, supercapacitors, cyclic voltammetry, numerical model, ionic characteristic, current density, power density, capacitive performance

中图分类号:

TK 02

卞时刚, 孟婷婷, 杨理理. 基于循环伏安法的热充电超级电容器数值研究[J]. 发电技术, 2025, 46(6): 1176-1183.

Shigang BIAN, Tingting MENG, Lili YANG. Numerical Study of Thermal Charging Supercapacitors Based on Cyclic Voltammetry[J]. Power Generation Technology, 2025, 46(6): 1176-1183.

图/表 11

图1 热充电超级电容器的结构

Fig. 1 Structure of thermal charging supercapacitors

表1 数值模型的几何参数

Tab. 1 Geometric parameters of the numerical model

参数	数值
计算单元宽度/μm	1 000
计算单元高度/μm	270
负极厚度/μm	30
隔膜厚度/μm	50
上下电解质域厚度/μm	80
正极厚度/μm	30

图2 数值模型的边界条件

Fig. 2 Boundary conditions for the numerical model

表2 数值模型的计算参数

Tab. 2 Computational parameters of the numerical model

参数	数值
阳离子电荷z₁/C	1.6×10^-9
阴离子电荷z₂/C	1.6×10^-9
单位体积离子浓度c₀/(mol/L)	1
电解液离子扩散系数/(m²/s)	$D 1 T$
正极离子扩散系数/(m²/s)	$D 2 T$
负极离子扩散系数/(m²/s)	$D 3 T$
低温热源温度T₀/K	298.150
高温热源温度T/K	303.150~348.150
线性电压扫描速率v/(V/s)	10^-3~10²
最小扫描电压V_min/V	0
最大扫描电压V_max/V	1.200

表2 数值模型的计算参数

Tab. 2 Computational parameters of the numerical model

参数	数值
阳离子电荷z₁/C	1.6×10^-9
阴离子电荷z₂/C	1.6×10^-9
单位体积离子浓度c₀/(mol/L)	1
电解液离子扩散系数/(m²/s)	$D 1 T$
正极离子扩散系数/(m²/s)	$D 2 T$
负极离子扩散系数/(m²/s)	$D 3 T$
低温热源温度T₀/K	298.150
高温热源温度T/K	303.150~348.150
线性电压扫描速率v/(V/s)	10^-3~10²
最小扫描电压V_min/V	0
最大扫描电压V_max/V	1.200

图3 网格独立性分析

Fig. 3 Grid independence analysis

图4 数值模型验证

Fig. 4 Numerical model validation

图5 低扫描速率下不同离子尺寸比的循环伏安曲线

Fig. 5 Cyclic voltammetry curves for different ion size ratios at low scan rates

图6 高扫描速率下不同阳离子尺寸的循环伏安曲线

Fig. 6 Cyclic voltammetry curves of different cation sizes at high scan rates

图7 功率密度随离子类型的变化

Fig. 7 Variation of power density with ion type

图8 阳离子浓度随温差的变化

Fig. 8 Variation of cation concentration with temperature difference

图9 阳离子最大浓度与温差的关系

Fig. 9 Relationship between maximum cation concentration and temperature difference

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