Amphenol (United States)

Li-ion battery thermal runaway is a critical safety issue for large-scale battery packs. Upon battery failure, gas venting can occur when the cell's internal pressure exceeds a critical value and causes cell rupture and electrolyte leakage. The gas venting is usually categorized into first venting events and thermal runaway gas venting events (second venting). The first venting occurs around 120 °C and can be considered as a precursor to thermal runaway. The subsequent venting during thermal runaway is more aggressive and releases more vent-gas.Detecting battery failures immediately after the first venting is critical to take action before the failure evolves into a thermal runaway event. Therefore, a gas detection method targeting first venting gas will be the focus. Early studies of first venting gas composition showed that CO2 is the primary gas component in battery overheating tests, nail penetration tests, and overcharging tests, while the gas composition in battery external short circuit tests was not revealed.To this end, an external short circuit test for a pouch 4.6 Ah cell was performed in a non-sealed acrylic box, which has around 21.5 L volume. Shortly after the initiation of external short circuit, the battery expansion force rises due to gas generation inside the pouch cell. The force then dropped suddenly indicating a gas venting event, which occurred when the cell temperature reached 114 °C. A Non-Dispersive Infrared (NDIR) CO2 sensor was used. The CO2 sensor reading started to increase within 5 seconds of gas venting and reached a maximum of 1,500 ppm as shown in the figure.To apply the gas detection strategies for first venting events, a detection threshold is required for different cells at different abuse conditions. To model the gas evolution process, the evolution of side reactions, mainly the SEI decomposition at high temperatures was considered. The released CO2 in first venting events can be estimated at different abuse conditions. The estimated CO2 amount can help determine the detection threshold of gas concentration for a given battery system. Figure 1

This chapter describes the coaxial cable design as well as the communication network that used it, with amplifiers, repeaters, and filters. It illustrates coaxial cables as the transmission line for telegraph, telephone, and TV applications. The type of insulator used in the cable construction provides mechanical strength and support for both the outer conductor and the overall cable design. Characteristic impedance is the combined opposition to the flow of electrical energy within the coaxial line or cable. Impedance is a complex value, derived from the combined equivalent of the resistance, capacitance, and inductive and conductive values of the cable. Capacitance of a coaxial cable is the ability of the cable to retain a charge. The two main attributes of a coaxial cable that effect its attenuation are DC resistance and the dissipation factor of the dielectric insulator. The automotive industry continually asks the coaxial cable manufacturers to test the limits of physics and manufacturing capabilities.

In this paper, a specially designed method for inspecting and categorizing whiskers in press-fit systems was established. Effect of PTH final hole diameter and pin coating thickness on whisker growth was evaluated. It was found that PTH final hole diameter showed more significant effect on whisker growth than pin coating thickness. The smaller the hole was, the more and longer whiskers grow in the press-fit system. However, thicker coating on pins introduced more scratched residue on annular rings and also could increase the chance of short circuit failure. The tin coating thickness on pins for telecom/datacom applications is recommended to between 0.5 μm and 2.5 μm.

In the present study, compared with a baseline case using only low loss air dielectric, the efficacy of six lossy materials in reducing worst-case crosstalk for signal data up to 10 Gbps is evaluated on a simplified connector structure. The connector structure consists of a triple stack up of 5 signal conductor microstrips plus a ground cover for a total of 15 microstrip transmission lines. All lossy materials from this study provide a measurable improvement in SNR, to varying degrees, when tested in this specific shared return conductor microstrip connector structure.

The paper is to investigate the chassis influence on the specific absorption rate (SAR) characteristics of handset antennas with the finite-difference time-domain method. The chassis is conductive and equipped with a quarter-wavelength monopole. The optimal chassis sizes have been presented for 900 MHz and 2 GHz operation.

Wavelength Division Multiplexing (WDM), a method for combining a multiplicity of different wavelength signals onto a single optical fiber, is finding increasing usage in optical fiber communications systems. Most commonly, WDM's are used in long haul communications to increase the transmission capacity on trunks, and in datacomm applications where high-isolation, bi-directional transmission is required.

A simplified model is presented that accurately predicts the coupling limitations of asymmetric fused multimode star (mxn) couplers fabricated from fibers with arbitrary core radii and numerical aperture values. The model assumes that the following conditions within the coupling region are met: a) the ratio of the cladding thickness between adjacent cores to the core radius (t/r) is much greater than 0.1, b) each fiber has an identical core index profile coefficient, c) the refractive index of each fiber's cladding is identical, and d) the fibers are substantially tapered. The model is shown to be equally applicable to symmetric couplers fused from identical fibers. In addition, experimental results supporting the model are presented.

The performance characteristics of any multimode fiber optic component, be it connector, coupler, multiplexer, or switch, are dependent on the modal intensity profile at the input of the device. It follows that any component that restructures the modal distribution from its input ports to its output ports can affect the overall system performance by modifying the operation of downstream parts. Specifically, commonly available multimode couplers are known to modify the input modal distribution as a result of the coupling mechanism; typically, the coupled fiber includes an overabundance of higher order modes while the straight through fiber suffers from a depletion of these higher order modes. The modal profiles of the coupler output ports can be actively monitored during the manufacturing process, thus allowing this information to be fed back to optimize the resulting device. The results of such measurements, which show the evolution of the coupling process during fabrication, will be presented and discussed. This capability raises questions concerning quality control measures, specifications, and the actual influence of a single component's capability on different systems' overall performance.

Implementation of single-mode optical fiber systems depends largely on the availability of integrated optical components for such functions as switching, multiplexing, and modulation. The technology of integrated optics is maturing very rapidly, and its growth justifies the optimism that now exists in the optical community.