Safety characteristics of Li-ion batteries evaluated by in situ measurement techniques

Abstract

Li-ion batteries hold an important place in the field of high power batteries because of their high open circuit voltage and associated high energy density. However, the safety is less satisfactory; therefore, the study of the factors that affect the safety of Li-ion batteries has much meaning to the safety design. In this paper, a set of apparatus was developed for in situ measurements, and several commercial materials including electrolyte, separator and electrode materials for Li-ion batteries were investigated by the in situ method. The results showed: 1) The electrolyte vapor pressure is influenced significantly by the component with low boiling point and increases rapidly with the increasing of temperature; 2) the shutdown of separator occurs at around 135℃ and the impedance increases approximately by two orders of magnitude; 3) carbon anode materials affect the most the volume changes of the cell, and the change for a graphite anode is much greater than that of a glassy carbon anode.

Powering MEMS portable devices—a review of non-regenerative and regenerative power supply systems with special emphasis on piezoelectric energy harvesting systems

“…Advantages of lithium-ion batteries are their relatively long cycle life, broad temperature range, long shelf life, low self-discharge rate, rapid charge capability, high rate and power discharge capability, high energy efficiency, high operating voltage, lack of memory effect, and high specific energy and energy density compared to other battery electrochemistries (table 2 [2-7, 61, 68-73] and table 3 [2,3,9,[74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89] and figure 1). Disadvantages include their degradation at high operating temperatures, need for protective circuitry for charging of cells, capacity loss or thermal runaway when overcharged, and venting when crushed [73,90,91]. Specific challenges to the implementation of lithium-ion thin-film, thick-film and microbattery battery technologies to portable electronics include present limitations on intercalation of sufficiently high volumes of lithium and the irreversibility of the structural changes that result from the intercalation [6]; integration of fabrication techniques with CMOS techniques; development of economical substrates other than platinum or platinum coated substrates [92]; management of capacity fade with cycling [93] and reduction of interface degradation [94,95].…”

“…Disadvantages include their degradation at high operating temperatures, need for protective circuitry for charging of cells, capacity loss or thermal runaway when overcharged, and venting when crushed [73,90,91]. Specific challenges to the implementation of lithium-ion thin-film, thick-film and microbattery battery technologies to portable electronics include present limitations on intercalation of sufficiently high volumes of lithium and the irreversibility of the structural changes that result from the intercalation [6]; integration of fabrication techniques with CMOS techniques; development of economical substrates other than platinum or platinum coated substrates [92]; management of capacity fade with cycling [93] and reduction of interface degradation [94,95].…”

A revision of the geographical distributions of the shrews Crocidura tanakae and C. attenuata based on genetic species identification in the mainland of China

“…We conducted a morphological investigation of the specimens sampled to identify the two species by determining three external measurements: total body length (TBL), head and body length (HBL), ear length (EL); and 10 skull measurements: greatest length of skull (GLS), cranial base length (GBL), median palatal length (MPL), length of teeth row (LUTR), greatest palatal breadth (GPB), breadth of occipital condyles (BOC), greatest breath of braincase (BBC), interorbital breadth (IOB), height of the braincase (HB), length of mandible (LM) according to Yang et al (2005, 2007) and Jenkins et al (2009).The measurements of the skull indices were performed with a digital vernier caliper (0.01 mm). Juveniles and sub-adults were excluded from the analysis according to the complete fusion of cranial sutures (Motokawa et al 1997, 2003), and by making a histogram of the HBL as an indicator for age identification of small mammals (Li et al 1989, 1990; Yang 1990).…”