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Intro to reed switches, magnets, magnetic fields

This brief introductory video on the DigiKey site offers tips for engineers designing with reed switches. Dr. Stephen Day, Ph.D. from Coto Technology gives a solid overview on reed switches -- complete with real-world application examples -- and a detailed explanation of how they react to magnetic fields.
View the video.

Bi-color LEDs to light up your designs

Created with engineers and OEMs in mind, SpectraBright Series SMD RGB and Bi-Color LEDs from Visual Communi-cations Company (VCC) deliver efficiency, design flexibility, and control for devices in a range of industries, including mil-aero, automated guided vehicles, EV charging stations, industrial, telecom, IoT/smart home, and medical. These 50,000-hr bi-color and RGB options save money and space on the HMI, communicating two or three operating modes in a single component.
Learn more.

All about slip rings: How they work and their uses

Rotary Systems has put together a really nice basic primer on slip rings -- electrical collectors that carry a current from a stationary wire into a rotating device. Common uses are for power, proximity switches, strain gauges, video, and Ethernet signal transmission. This introduction also covers how to specify, assembly types, and interface requirements. Rotary Systems also manufactures rotary unions for fluid applications.
Read the overview.

Seifert thermoelectric coolers from AutomationDirect

Automation-Direct has added new high-quality and efficient stainless steel Seifert 340 BTU/H thermoelectric coolers with 120-V and 230-V power options. Thermoelectric coolers from Seifert use the Peltier Effect to create a temperature difference between the internal and ambient heat sinks, making internal air cooler while dissipating heat into the external environment. Fans assist the convective heat transfer from the heat sinks, which are optimized for maximum flow.
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EMI shielding honeycomb air vent panel design

Learn from the engineering experts at Parker how honeycomb air vent panels are used to help cool electronics with airflow while maintaining electromagnetic interference (EMI) shielding. Topics include: design features, cell size and thickness, platings and coatings, and a stacked design called OMNI CELL construction. These vents can be incorporated into enclosures where EMI radiation and susceptibility is a concern or where heat dissipation is necessary. Lots of good info.
Read the Parker blog.

What is 3D-MID? Molded parts with integrated electronics from HARTING

3D-MID (three-dimensional mechatronic integrated devices) technology combines electronic and mechanical functionalities into a single, 3D component. It replaces the traditional printed circuit board and opens up many new opportunities. It takes injection-molded parts and uses laser-direct structuring to etch areas of conductor structures, which are filled with a copper plating process to create very precise electronic circuits. HARTING, the technology's developer, says it's "Like a PCB, but 3D." Tons of possibilities.
View the video.

Loss-free conversion of 3D/CAD data

CT CoreTech-nologie has further developed its state-of-the-art CAD converter 3D_Evolution and is now introducing native interfaces for reading Solidedge and writing Nx and Solidworks files. It supports a wide range of formats such as Catia, Nx, Creo, Solidworks, Solidedge, Inventor, Step, and Jt, facilitating smooth interoperability between different systems and collaboration for engineers and designers in development environments with different CAD systems.
Learn more.

Top 5 reasons for solder joint failure

Solder joint reliability is often a pain point in the design of an electronic system. According to Tyler Ferris at ANSYS, a wide variety of factors affect joint reliability, and any one of them can drastically reduce joint lifetime. Properly identifying and mitigating potential causes during the design and manufacturing process can prevent costly and difficult-to-solve problems later in a product lifecycle.
Read this informative ANSYS blog.

Advanced overtemp detection for EV battery packs

Littelfuse has introduced TTape, a ground-breaking over-temperature detection platform designed to transform the management of Li-ion battery systems. TTape helps vehicle systems monitor and manage premature cell aging effectively while reducing the risks associated with thermal runaway incidents. This solution is ideally suited for a wide range of applications, including automotive EV/HEVs, commercial vehicles, and energy storage systems.
Learn more.

Benchtop ionizer for hands-free static elimination

EXAIR's Varistat Benchtop Ionizer is the latest solution for neutralizing static on charged surfaces in industrial settings. Using ionizing technology, the Varistat provides a hands-free solution that requires no compressed air. Easily mounted on benchtops or machines, it is manually adjustable and perfect for processes needing comprehensive coverage such as part assembly, web cleaning, printing, and more.
Learn more.

LED light bars from AutomationDirect

Automation-Direct adds CCEA TRACK-ALPHA-PRO series LED light bars to expand their offering of industrial LED fixtures. Their rugged industrial-grade anodized aluminum construction makes TRACKALPHA-PRO ideal for use with medium to large-size industrial machine tools and for use in wet environments. These 120 VAC-rated, high-power LED lights provide intense, uniform lighting, with up to a 4,600-lumen output (100 lumens per watt). They come with a standard bracket mount that allows for angle adjustments. Optional TACLIP mounts (sold separately) provide for extra sturdy, vibration-resistant installations.
Learn more.

World's first metalens fisheye camera

2Pi Optics has begun commercial-ization of the first fisheye camera based on the company's proprietary metalens technology -- a breakthrough for electronics design engineers and product managers striving to miniaturize the tiny digital cameras used in advanced driver-assistance systems (ADAS), AR/VR, UAVs, robotics, and other industrial applications. This camera can operate at different wavelengths -- from visible, to near IR, to longer IR -- and is claimed to "outperform conventional refractive, wide-FOV optics in all areas: size, weight, performance, and cost."
Learn more.

Orbex offers two fiber optic rotary joint solutions

Orbex Group announces its 700 Series of fiber optic rotary joint (FORJ) assemblies, supporting either single or multi-mode operation ideal for high-speed digital transmission over long distances. Wavelengths available are 1,310 or 1,550 nm. Applications include marine cable reels, wind turbines, robotics, and high-def video transmission. Both options feature an outer diameter of 7 mm for installation in tight spaces. Construction includes a stainless steel housing.
Learn more.

Mini tunnel magneto-resistance effect sensors

Littelfuse has released its highly anticipated 54100 and 54140 mini Tunnel Magneto-Resistance (TMR) effect sensors, offering unmatched sensitivity and power efficiency. The key differentiator is their remarkable sensitivity and 100x improvement in power efficiency compared to Hall Effect sensors. They are well suited for applications in position and limit sensing, RPM measurement, brushless DC motor commutation, and more in various markets including appliances, home and building automation, and the industrial sectors.
Learn more.

Panasonic solar and EV components available from Newark

Newark has added Panasonic Industry's solar inverters and EV charging system components to their power portfolio. These best-in-class products help designers meet the growing global demand for sustainable and renewable energy mobility systems. Offerings include film capacitors, power inductors, anti-surge thick film chip resistors, graphite thermal interface materials, power relays, capacitors, and wireless modules.
Learn more.

Safer, easier-to-recycle all-carbon lithium battery developed by Rensselaer researchers

Engineering researchers at Rensselaer Polytechnic Institute have developed a new type of rechargeable lithium battery with components made entirely of carbon. Unlike the lithium-ion batteries currently sold around the world to power smartphones, laptops, and countless other devices, this new battery is made without the toxic metal cobalt.

The new technology, detailed in a research paper published in late April in the journal Nature Communications, pairs an anode and cathode made from the nanomaterial graphene with metallic lithium to create an energy storage device. This research could lead to a new generation of batteries with significantly higher energy density that are nontoxic, easy to manufacture, and inexpensive to recycle.

Unlike the lithium-ion batteries currently sold around the world, this new battery is made without the toxic metal cobalt. Shown is a prototype of the battery powering a commercial LED device. [Photo credit: Rensselaer/Koratkar]

 

 

 

 

"In this study, we show how to make a new type of battery using graphene, as well as an unlikely component: metallic lithium," said Nikhil Koratkar, the John A. Clark and Edward T. Crossan Professor of Engineering at Rensselaer, who led the study. "Metallic lithium is avoided in lithium-ion batteries due to its tendency to form dendrites that are considered unsafe, but we show that metallic lithium trapped within a porous graphene structure is safe and does not form dendrites. The result is an all-carbon lithium battery that offers up to three times higher energy density than conventional batteries. It is also more environmentally friendly, and with its simplified chemistry could be easier and less expensive to mass produce."

The study is titled "Defect-induced plating of lithium metal within porous graphene networks."

Lithium battery technology dates back to the 1970s, and some of the very first iterations used a metal lithium cathode. Energy is stored by moving lithium ions back and forth between the battery's cathode and an anode made of graphite. This results in a flow of electrons, which is harvested and put to use as electricity.

As the lithium gets cycled back and forth between the anode and cathode, it would settle and form dendrites -- small, sharp towers on the cathode surface -- that over time grow in size and eventually pierce the membrane separating the cathode and anode, causing the battery to fail. Even though lithium metal has an attractive energy density, this shortcoming led to serious safety concerns. As a consequence, the battery industry has avoided the use of metallic lithium and has resorted to storing elemental lithium in a matrix material such as cobalt-oxide or iron-phosphate. Atoms of cobalt or iron in the matrix bond with lithium and prevent lithium metal from forming, thereby solving the dendrite issue.

In a new study, researchers at Rensselaer demonstrated how battery components made from the nanomaterial graphene, with its porous structure, entrap lithium metal and prevent the growth of dendrites. [Photo credit: Rensselaer/Koratkar]

 

 

 

 

In most lithium-ion batteries sold today, the cathode is made from lithium cobalt oxide and the anode is made from graphite, comprised of many ultra-thin layers of graphene. When charging, lithium ions seek out the edges of the anode and work their way inside between the layers of graphene. This process, called intercalation, creates no bonds between the elemental lithium or between the lithium and graphene, which limits the energy density of the overall battery.

In place of graphite, Koratkar and his research team developed an anode made from thermally shocked graphene. This process is a way to intentionally create cracks, holes, voids, and other defects in the graphene. In previous studies, the researchers have shown that these defects enable lithium ions to more rapidly make their way into the anode, leading to shorter charge times.

In this study, however, they looked at the interaction of elemental lithium with such defect sites in the graphene. They found that lithium ions are strongly attracted to defect sites, which creates a very high local concentration of lithium near the defects. This initiates the formation, or "plating," of metallic lithium at the defect sites, which significantly increases the energy density of the battery. Such graphene-lithium metal composites can be used as the cathode, eliminating the need for toxic metals or complicated chemistries associated with lithium cobalt oxide or lithium iron phosphate.

However, what surprised the research team was that even after thousands of charge-recharge cycles, as the metallic lithium transitioned back and forth between the anode and cathode, no significant dendrites formed.

"We discovered that the porous graphene network acts as a caged entrapment for lithium metal that prevents dendritic growth, facilitating extended cycling of the electrode," Koratkar said. "The result is a device with excellent energy density and stable performance. We are excited about its potential as a new type of battery."

When compared to traditional graphitic anodes and conventional lithium cobalt oxide cathodes, the new graphene-lithium metal composite electrode provides higher charge storage capacity and up to three times higher energy density. Extended testing for over 1,000 charge-discharge cycles showed highly stable performance. Importantly, even after 1,000 cycles there was no indication of any significant dendritic structures, since the lithium metal is caged within the pores of the porous graphene network structure. To demonstrate the concept, the researchers built a cell using graphene electrodes and used it to power a commercial LED device.

Along with Koratkar, co-authors of the paper are: graduate students Rahul Mukherjee, Abhay Thomas, and Eklavya Singh, and visiting scientist Osman Eksik, of the Rensselaer Department of Mechanical, Aerospace, and Nuclear Engineering; graduate student Dibakar Datta of Brown University; and postdoctoral scientist Junwen Li and Professor Vivek Shenoy of the University of Pennsylvania.

Source: Rensselaer Polytechnic Institute

Published May 2014

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