Optimization of a phase change material based internal cooling system for cylindrical Li-ion battery pack and a hybrid cooling design

Zhu

et al. 2018

Summary Due to the sensitivity of the electrochemical performance of lithium‐ion batteries to temperature, the thermal management system becomes an essential component of pure electric vehicles. This paper selects a liquid‐cooled double‐layer battery pack for a certain car as the research object, determines the heating power of the battery cell through experiments, considers the existence of air domain in the battery pack to establish a battery pack thermal management system model, and analyzes the effects of different discharge rates, inlet flow rates, and inlet flow directions on the thermal performance of the double‐layer battery pack. The results show that the temperature of the upper module of the double‐layer battery pack is higher than that of the lower module at the same discharge rates and inlet flow rate; the maximum temperature of the upper module can be effectively reduced by increasing the liquid intake flow of the upper module. When the inlet flow rate of the upper module and the lower module is 550 and 500 L/hour respectively, the temperature distribution difference between the upper and lower modules of the double‐layer battery pack is the smallest, and the heat dissipation performance of the battery pack is the better. The conclusion can provide reference for structural design and optimization of thermal management system of the liquid‐cooled double‐layer battery pack.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Heat dissipation analysis of double-layer battery pack under coupling heat transfer of air, liquid, and solid

Zhu

et al. 2018

“…If the experimental results of the TTC tests agree well with the numerical results at different heat rates and cooling conditions, the model is credible to solve the energy balancing processes that involve heat generation, phase change, and convection for batteries with different thermal properties. To show the cooling performance of the PCM core cooling system on real Li‐ion batteries, the heat generation rates of a 2.6 Ah commercial 18650 Li‐ion battery were considered in the model, with the heat generation rates of 12 527 and 59 235 W m −3 for the 2.5 and 5 A discharges, respectively . The relevant parameters and physical properties of the Li‐ion battery are summarized in Table .…”

Section: Experiments and Thermal Modelmentioning

confidence: 99%

“…To show the cooling performance of the PCM core cooling system on real Li-ion batteries, the heat generation rates of a 2.6 Ah commercial 18650 Li-ion battery were considered in the model, with the heat generation rates of 12 527 and 59 235 W m −3 for the 2.5 and 5 A discharges, respectively. 33 The relevant parameters and physical properties of the Li-ion battery are summarized in Table 3.…”

Section: Fabrication Of a Thermal Test Cellmentioning

confidence: 99%

Performance assessment of a passive core cooling design for cylindrical lithium-ion batteries

Liu

2018

Self Cite

Summary Battery thermal management (BTM) system is an indispensable component for large‐sized lithium‐ion battery packs used in aerospace and automotive applications. Besides providing a proper temperature range for batteries to operate, thus improving their efficiency, lifespan, and safety, the BTM system also needs to be well designed with considering the cost, weight, and practicability. In this paper, an internal passive BTM system is proposed for the cylindrical Li‐ion batteries. The design embeds a phase change material (PCM) filled mandrel inside the battery to achieve the cooling effect. A thermal test cell is first fabricated and tested in a wind tunnel under different cooling scenarios, and it is also used to verify a numerical thermal model. The proposed BTM system is further examined through the model and found to be able to create a preferable environment for batteries to operate. Specifically, the core BTM system consumes less PCM and achieves lower temperature rises and more uniform temperature distributions than an external BTM system. The proposed design can also exert its full latent heat to manage the heat generated from the battery without having a thermally conductive matrix, which is usually composite with PCM in external BTM systems. In addition, experiments show that the battery equipped with the proposed BTM system is ready for intensive cycling tests.

“…BTMSs can be categorized into active and passive modes 3,4 . The active BTMSs circulate air or liquid through fans or pumps in cooling channels to extract the heat generated by batteries, while the passive BTMSs manage battery heat generation without consuming supplementary energy, and the examples include phase change materials cooling, 5‐10 hydrogel cooling, 11‐13 and boiling liquid cooling 14‐16 . As the modern trend toward increasing batteries' power density and fast charging performance, that is, higher C rates (for example, 2 C indicates the current that can fully charge or discharge a battery in 1/2 hour), the parasitic heat generation in batteries can increase, which poses extra challenges on the BTMSs.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of a direct evaporative cooling approach for Li‐ion battery thermal management

Liu

et al. 2020

Self Cite

Summary A desirable operating temperature range and small temperature gradient is beneficial to the safety and longevity of lithium‐ion (Li‐ion) batteries, and battery thermal management systems (BTMSs) play a critical role in achieving the temperature control. Having the advantages of direct access and low viscosity, air is widely used as a cooling medium in BTMSs. In this paper, an air‐based BTMS is modified by integrating a direct evaporative cooling (DEC) system, which helps reduce the inlet air temperature for enhanced heat dissipation. Experiments are carried out on 18650‐type batteries and a 9‐cell battery pack to study how relative humidity and air flow rate affect the DEC system. The maximum temperatures, temperature differences, and capacity fading of batteries are compared between three cooling conditions, which include the proposed DEC, air cooling, and natural convection cooling. In addition, a DEC tunnel that can produce reciprocating air flow is assembled to further reduce the maximum temperature and temperature difference inside the battery pack. It is demonstrated that the proposed DEC system can expand the usage of Li‐ion batteries in more adverse and intensive operating conditions.