Investigations of Li-Ion Battery Thermal Management Systems Based on Heat Pipes: A Review

Abstract

With increasing concerns about carbon emissions and the resulting climate impacts, Li-ion batteries have become one of the most attractive energy sources, especially in the transportation sector. For Li-ion batteries, an effective thermal management system is essential to ensure high-efficiency operation, avoid capacity degradation, and eliminate safety issues. Thermal management systems based on heat pipes can achieve excellent cooling performance in limited space and thus have been widely used for the temperature control of Li-ion batteries. In this paper, the thermal management systems of Li-ion batteries based on four types of heat pipes, i.e., flat single-channel heat pipes, oscillating heat pipes, flexible heat pipes, and microchannel heat pipes, are comprehensively reviewed based on the studies in the past 20 years. The effects of different influencing factors on the cooling performance and thermal runaway behavior of Li-ion batteries are thoroughly discussed in order to provide an in-depth understanding for researchers and engineers. It is concluded that for all types of thermal management systems based on heat pipes, water spray cooling could achieve better cooling performance than forced air cooling and water bath cooling, while its energy consumption is obviously smaller than forced air cooling. For thermal management systems based on oscillating heat pipes, improved heat transfer characteristics could be achieved by increasing the number of turns, using a relatively larger inner hydraulic diameter and using a length ratio between the evaporator and condenser higher than 1.0. Heat pipes fabricated by flexible materials suffer from permeation of noncondensable gases from ambient and leakage of working fluid. These issues could be partly resolved by adding thermal vias filled with metallic materials and covering the sealing part with indium coating or designing a multilayered structure with metallic materials in it. Moreover, the limitations and future trends of Li-ion battery thermal management systems based on heat pipes are presented. It is pointed out that the thermal runaway behavior and heating performance of battery thermal management systems based on heat pipes should be further elaborated. The analysis of this paper could provide valuable support for future investigations on Li-ion battery thermal management systems based on heat pipes; it could also guide the choice and design of Li-ion battery thermal management systems based on heat pipes in commercial use.

Figure 1

Schematic diagram of heat pipe. Reprinted with permission from ref (23). Copyright 2021 Elsevier.

Figure 2

Schematic diagram of cooling systems based on heat sink and heat sink combined with heat pipe. Reprinted with permission from ref (25). Copyright 2014 Elsevier.

Figure 3

Schematic diagram of BTMS based on heat pipe combined with PCM plate and forced air cooling method. Reprinted with permission from ref (28). Copyright 2017 Elsevier.

Figure 4

A typical schematic of BTMS based on oscillating heat pipe. Reprinted with permission from ref (38). Copyright 2021 Elsevier.

Figure 5

Variations of thermal resistance for oscillating heat pipe charged with ethanol–water mixtures at different mixing ratios: (a) FR = 30%; (b) FR = 40%; (c) FR = 50%. Reprinted with permission from ref (55). Copyright 2019 Elsevier.

Figure 6

Schematic of two-dimensional (2D) oscillating heat pipe (OHP), 3 layers three-dimensional (3D) OHP, and 4 layers 3D OHP. Reprinted with permission from ref (53). Copyright 2019 Elsevier.

Figure 7

Schematic of a leaf-shaped oscillating heat pipe. Reprinted with permission from ref (59). Copyright 2020 Elsevier.

Figure 8

Structure of a dual-serpentine-channel oscillating heat pipe. Reprinted with permission from ref (61). Copyright 2020 Elsevier.

Figure 9

Experiment set up for the visualization of the inside flow pattern of oscillating heat pipe(a) and the image of bubble generation and growth(b). Reprinted with permission from ref (74), Copyright 2013 Elsevier.

Figure 10

Structure of flexible heat pipe with rubber adiabatic section. Reprinted with permission from ref (88). Copyright 2016 Elsevier.

Figure 11

Photo of different configurations of flexible heat pipe: (i) I shape, (ii) stair-step shape, (iii) inverted-U shape, and (iv) N shape. Reprinted with permission from ref (89). Copyright 2017 Elsevier.

Figure 12

Configuration of U-shaped microchannel heat pipe. Reprinted with permission from ref (104). Copyright 2021 Elsevier.