scholarly journals Discharge Profile and Its Correlation with Estimated Parametric Sensitivity and Electrical Contact Resistance Losses in Li-Ion Battery

Author(s):  
G Thamarai Selvi ◽  
Shailendra Kumar Jha
Author(s):  
Peyman Taheri ◽  
Scott Hsieh ◽  
Majid Bahrami

Lithium-ion (Li-ion) batteries are favored in hybrid-electric vehicles and electric vehicles for their outstanding power characteristics. In this paper the energy loss due to electrical contact resistance (ECR) at the interface of electrodes and current-collector bars in Li-ion battery assemblies is investigated for the first time. ECR is a direct result of contact surface imperfections and acts as an ohmic resistance at the electrode-collector joints. ECR is measured at electrode connections of a sample Li-ion battery, and a straightforward analysis is presented to evaluate the relevant energy loss. Through the experiments, it is observed that ECR is an important issue in energy management of Li-ion batteries. Effects of surface imperfection, contact pressure, joint type, collector bar material, and interfacial materials on ECR are highlighted. The obtained data show that in the considered battery, the energy loss due to ECR can be as high as 20% of the total energy flow in and out of the battery under normal operating conditions. However, ECR loss can be reduced to 6% when proper joint pressure and/or surface treatment are used. A poor connection at the electrode-collector interface can lead to a significant battery energy loss as heat generated at the interface. At sever conditions, heat generation due to ECR might cause serious safety issues, thermal runaway, sparks, and even melting of the electrodes.


2016 ◽  
Vol 108 (18) ◽  
pp. 181903 ◽  
Author(s):  
Gaurav Singh ◽  
R. L. Narayan ◽  
A. M. Asiri ◽  
U. Ramamurty

1987 ◽  
Vol 109 (4) ◽  
pp. 587-591 ◽  
Author(s):  
M. Suzuki ◽  
K. C. Ludema

Steel cylinders were slid against flat steel disks, using a liquid lubricant, in order to study the progression of events associated with “running-in.” It was found that, when using mineral oil, the electrical contact resistance varied over a small range of high values indicating no metallic contact, whereas with engine oil a high resistance with an intermittent negligible contact resistance was found. A surface film forms from the additives in the engine oil which produces lower wear, slightly higher friction, a retarded running-in, and a rougher surface finish in the direction of sliding than does the mineral oil. A film which is composed only of Fe3O4 is formed when mineral oil is used. In addition, the mineral oil lubricated surfaces develop a conforming waviness across the sliding tracks. The oxide must have enhanced this surface conformity since it was not seen in the surfaces lubricated with engine oil. The role of the oxide may be further seen in experiments in which wear debris that accumulated in the entrance region of specimen contact was removed at frequent intervals. Little conforming waviness was seen in the latter case, suggesting that oxide which gathered in the entrance region abraded grooves in the steel surfaces. After the oxides were dislodged the friction increased and the contact resistance decreased for a time, indicating that the oxide acted like a solid lubricant.


Author(s):  
Brian Jensen ◽  
Zhongde Wang ◽  
Kazuhiro Saitou ◽  
John L. Volakis ◽  
Katsuo Kurabayashi

Improving the power handling capability of direct contact RF MEMS switches requires a knowledge of conditions at the contact. This paper models the temperature rise in a direct contact RF MEMS switch, including the effects of electrical and thermal contact resistance. The maximum temperature in the beam is found to depend strongly on the power dissipation at the contact, with almost no contribution from dissipation due to currents in the rest of the switch. Moreover, the maximum temperature is found to exceed the limit for metal softening for a significant range of values of thermal and electrical contact resistance. Since local contact asperity temperature can be hundreds of degrees higher than the bulk material temperature modeled here, these results underscore the importance of understanding and controlling thermal and electrical contact resistance in the switch.


2015 ◽  
Vol 3 (20) ◽  
pp. 10942-10948 ◽  
Author(s):  
Wei Weng ◽  
Qingqing Wu ◽  
Qian Sun ◽  
Xin Fang ◽  
Guozhen Guan ◽  
...  

Failure mechanism is investigated for the first time in a Si-based fiber-shaped electrode. The interphase electrical contact resistance indicates the dominant failure mechanism, which is the loss of contact between the current collector/conductive network and the active material. The decreasing contact resistance denotes the loose interphase contact and a decreasing capacity.


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