A thermal performance management system for lithium-ion battery packs

Electric vehicles equipped with lithium-ion batteries face a huge challenge, and the fact that battery life is very much affected by the temperature conditions of their operating environment, the heat reduces battery life cycle and time and increases the likelihood of thermal degradation and explosion. This problem has forced engineers to cool the battery. The methods used to cool the battery includes a cool water method (passing water or a dielectric fluid from the battery pack), cooling air (blowing air into the battery compartment by the fan), using a refrigeration system (such as cooling screens), and the use of phase-change material (PCM). In this research after reviewing and referring to valid authorities, it was found that PCMs are superior to all three other cooling systems because the airconditioning system is not very desirable due to the high-temperature gradient between the battery cells. Also, cooling and refrigeration systems with refrigerant gases will also cost a very high cost on the electric car. The results of the studies showed that the cooling the battery using the PCM creates a similar temperature profile between the batteries in the battery pack, the temperature gradient is much smaller than the air cooler and cool water, and the final cost will be much lower. Also, it performs more efficiently in high-speed road dynamics and increases the battery life of an electric car or electric hybrid. K E Y W O R D S electric vehicles, lithium-ion batteries, phase-change materials (PCMs), thermal energy storage (TES)

Section: Exploring the Hybrid Battery Thermal Managementmentioning

confidence: 99%

“…The cooling of the battery is divided into three types of active, inactive, and hybrid cooling. 36 In the active method, air is often used as a cooling fluid, and it uses a fan to move it. In inactive cooling, fluid is applied, which does not require mechanical energy for cooling.…”

Section: Introducing Common Types Of Battery Coolingmentioning

confidence: 99%

Thermal behavior of lithium batteries used in electric vehicles using phase change materials

Bashirpour‐Bonab

2020

“…5,6 BTMS has been commercially applied with air cooling, 7-9 liquid cooling, 5,10-12 and ohmic heating. [13][14][15] Moreover, in recent years, some novel methods have been developed, such as phase-change materials cooling from liquid to gas [16][17][18][19] and from solid to liquid, [20][21][22] heat pipes cooling, 23,24 or a combination use of them. [25][26][27][28] The appropriate BTMS should comprehensively consider battery heat generation and the operating environment.…”

Section: Introductionmentioning

confidence: 99%

Simplification strategy research on hard‐cased Li‐ion battery for thermal modeling

Xifeng

Zeng²,

Hong-liang

et al. 2020

Summary Numerical simulation is widely used in research and design of the battery thermal management system (BTMS). Battery cells are commonly homogenized to a block for module or pack level modeling. However, how the homogenization method affects results is not proven. This paper works on a hard‐cased Li‐ion battery to find a proper simplification method. First, a detailed three‐dimensional thermal model (model A) is set up and validated by experimental data. Then, the other three models with different simplification strategies are proposed. They are model B (the cell is homogenized to a block), model C (the cell preserves only core region and housing case), and model D (based on model C, the thin insulation films are also considered). Take the results of model A as a reference, the calculation accuracy and efficiency are summarized. It is found that model B shows the best efficiency and is a proper choice for evaluation of temperature dynamics, while model D is more recommended when the internal temperature distribution of the battery is more concerned.

“…2 But the performance of lithium-ion batteries is greatly affected by environmental conditions, such as ambient temperature. 3,4 In cold weather, internal impedance of lithium-ion battery increases and capacity decreases significantly, 5,6 and the internal lithium-ion embedded in graphite anode is blocked. 7 Part of the lithium ions are converted into lithium metal deposited on the anode surface, and easily developed into lithium dendrites piercing diaphragm, causing short circuit, 8 which seriously affects battery cycle life and the mileage of the EVs.…”

Section: Introductionmentioning

confidence: 99%

“…Lithium‐ion battery has become the preferred energy source system (ESS) for EVs because of long life and high energy density 2 . But the performance of lithium‐ion batteries is greatly affected by environmental conditions, such as ambient temperature 3,4 . In cold weather, internal impedance of lithium‐ion battery increases and capacity decreases significantly, 5,6 and the internal lithium‐ion embedded in graphite anode is blocked 7 .…”

Section: Introductionmentioning

confidence: 99%

Preheatingstrategy ofvariable‐frequencypulse for lithium battery in cold weather

2020

Aiming to the issue of charging difficulty and capacity fading for lithium-ion battery at low temperature, this study proposes a preheating strategy using variablefrequency pulse. The innovation of this paper is to propose the thermo-electric coupling model based on the electrochemical impedance spectroscopy of battery at different temperatures, integrated with variable frequency changing for pulse method to develop an effective inner pre-heating strategy. Meanwhile, the evaluating method of impact of this strategy on capacity fading of battery has also been proposed to examine its effectiveness, to find the optimal strategy. First, temperature rise model and the thermo-electric coupling model at different temperatures according to the equivalent circuit model of battery are presented. Further, optimal heating frequency of current pulse at different temperatures is calculated according to the changing of internal impedance. The results show that the optimal variable-frequency pulse pre-heating strategy can heat the lithium-ion battery from −20 C to 5 C in 1000 seconds. Meanwhile, it brings less damage to the battery health and improves the performance of battery in cold weather based on the views of power consumption, capacity attenuation, and internal impedance changes.