双体系混装电池组热特性研究及风冷散热结构优化

doi:10.19799/j.cnki.2095-4239.2025.0122

摘要/Abstract

摘要：

锂离子电池在电动汽车领域的广泛应用存在性能方面的问题，为突破单一材料体系的限制，提出了三元锂电池与磷酸铁锂电池混用的双体系电池组设计方案，并已实现实车应用。为确保双体系电池组的热安全性，本工作研究了由18650三元锂电池与磷酸铁锂电池组成的双体系电池组的热特性。首先，建立了双体系电池组的三维电化学-热耦合模型，设计了Z形、U形和T形3种风冷散热结构，通过实验分析了两种锂离子电池产热差异并验证了所建立模型的精确性。对比不同位置的电池在自然风冷和强制风冷下的散热效果，优化了电池布局。研究结果表明，优化后的双体系电池组布局能有效降低电池组的最大温差，说明了该优化布局方案能够有效改善双体系电池组温度均匀性。当进口风速为8 m/s时，U形结构相较于Z形结构在最高温度、平均温度和最大温差上分别降低7.68%、6.86%和21.2%。最后，通过正交试验研究了U形结构的组内间距对散热的影响。Kruskal-Wallis检验结果表明，在1.5~4.5 mm内，组内间距对温度的影响较小，风冷结构和进口风速对散热性能的影响更为显著。

关键词: 锂离子电池, 双体系电池组, 风冷热管理系统, 数值模拟, 结构优化

Abstract:

The widespread application of lithium-ion batteries in electric vehicles is limited by performance constraints. To address the shortcomings of single-material systems, this study proposes a dual-system battery pack design integrating ternary lithium (NCM) and lithium iron phosphate (LFP) batteries, which has been successfully applied in practical vehicle systems. To ensure thermal safety, we investigate the thermal characteristics of a dual-system battery pack composed of 18650 NCM and LFP cells. A three-dimensional electrochemical–thermal coupling model is developed for the dual-system battery pack. Three air-cooling configurations (Z-type, U-type, and T-type) are designed, and experiments are conducted to analyze heat generation differences between the two cell types and to validate the model. Thermal dissipation performance under natural and forced air cooling is compared at different cell positions, leading to an optimized cell arrangement. The results show that the optimized layout effectively reduces the maximum temperature difference in the battery pack, improving temperature uniformity. At an inlet wind speed of 8 m/s, the U-type configuration reduces maximum temperature, average temperature, and maximum temperature difference by 7.68%, 6.86%, and 21.2%, respectively, compared to the Z-type configuration. Despite exhibiting a higher inlet-outlet pressure differential (78.21 Pa vs. 50.59 Pa for the Z-type), the U-type configuration achieves enhanced thermal uniformity through improved airflow distribution, effectively balancing cooling efficiency and pressure drop. Orthogonal experiments further examine the impact of intra-group spacing in the U-type configuration. Kruskal-Wallis test results indicate that within the range of 1.5—4.5 mm, intra-group spacing has minimal influence on temperature, while the cooling configuration and inlet air velocity predominantly determine thermal management performance. This research provides critical insights into optimizing thermal safety in hybrid battery systems.

Key words: lithium-ion batteries, dual-system battery packs, air-cooling thermal management system, numerical simulation, structural optimization

中图分类号:

TM 912

陈峥, 胡竞元, 赵志刚, 申江卫, 夏雪磊, 魏福星. 双体系混装电池组热特性研究及风冷散热结构优化[J]. 储能科学与技术, 2025, 14(9): 3463-3475.

Zheng CHEN, Jingyuan HU, Zhigang ZHAO, Jiangwei SHEN, Xuelei XIA, Fuxing WEI. Thermal characteristics study and optimization of air-cooling structures for dual-system battery packs[J]. Energy Storage Science and Technology, 2025, 14(9): 3463-3475.

图/表 17

图1

图2

图3

表1

两种电池的物性参数"

电池参数	数值	电池参数	数值
$ρ b a t t, N C M$ /(kg/m³)	2082.2	$ρ b a t t, L F P$ /(kg/m³)	2500.7
$k a, N C M$ /[W/(m·K)]	29.541	$k a, L F P$ /[W/(m·K)]	29.52
$k r, N C M$ /[W/(m·K)]	0.773	$k r, L F P$ /[W/(m·K)]	0.873
$c p, N C M$ /[J/(kg·K)]	1345.9	$c p, L F P$ /[J/(kg·K)]	1374.8

表1

图4

表2

图5

图6

表3

图7

图8

图9

表4

图10

图11

图12

表5

正交表及仿真结果"

组合	x₁/mm	x₂/mm	y₁/mm	y₂/mm	$T m a x$ /℃	$T a v e$ /℃	$Δ T m a x$ /℃
1	1.5	1.5	1.5	1.5	43.57	40.66	7.15
2	1.5	2.5	2.5	2.5	43.41	40.75	6.41
3	1.5	3.5	3.5	3.5	43.14	40.61	6.02
4	1.5	4.5	4.5	4.5	43.17	40.57	5.92
5	2.5	1.5	2.5	3.5	43.62	40.86	6.32
6	2.5	2.5	1.5	4.5	43.21	40.63	6.09
7	2.5	3.5	4.5	1.5	43.58	40.74	7.02
8	2.5	4.5	3.5	2.5	43.41	40.73	6.26
9	3.5	1.5	3.5	4.5	43.56	40.71	6.39
10	3.5	2.5	4.5	3.5	43.40	40.67	6.55
11	3.5	3.5	1.5	2.5	43.25	40.66	6.47
12	3.5	4.5	2.5	1.5	43.33	40.62	6.72
13	4.5	1.5	4.5	2.5	44.19	41.08	7.24
14	4.5	2.5	3.5	1.5	44.03	40.81	7.74
15	4.5	3.5	2.5	4.5	43.26	40.56	6.39
16	4.5	4.5	1.5	3.5	43.06	40.51	6.22

表5

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三元锂电池参数	数值	磷酸铁锂电池参数	数值
额定容量/Ah	2	额定容量/Ah	2
额定电压/V	3.6	额定电压/V	3.2
充电截止电压/V	4.2	充电截止电压/V	3.65
放电截止电压/V	2.5	放电截止电压/V	2.0

电池	参数	SOC
电池	参数	0.9	0.8	0.7	0.6	0.5	0.4	0.3	0.2	0.1	0
LFP	欧姆内阻/mΩ	58.0	57.6	58.0	57.1	58.6	55.2	58.9	58.3	55.5	63.8
	极化内阻/mΩ	27.6	32.0	34.4	35.0	33.2	39.0	39.4	45.9	58.9	91.5
	总内阻/mΩ	85.6	89.6	92.4	92.1	91.8	94.2	98.3	104.2	114.4	155.3

NCM	欧姆内阻/mΩ	36.6	36.6	36.6	36.9	37.2	37.2	37.9	38.7	38.7	36.6
	极化内阻/mΩ	9.9	11.2	12.1	11.7	8.4	8.0	7.7	9.0	10.1	9.9
	总内阻/mΩ	46.5	47.8	48.7	48.6	45.6	45.2	45.6	47.7	48.8	46.5

电池布局方式	散热结构	最高温度/℃	平均温度/℃	最大温差/℃
交替布局	Z形散热结构	51.30	45.76	13.48
	U形散热结构	47.72	43.05	8.92
	T形散热结构	48.65	44.27	10.75

优化布局	Z形散热结构	48.57	45.57	7.04
	U形散热结构	44.87	42.26	6.48
	T形散热结构	47.20	44.30	6.68