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ENERGY STORAGE pair link passing through each “tap” connection, as shown in figure 8. The bus application places a high voltage requirement on every transformer since the same twisted-pair potential must interface with any voltage on the floating cell-stack. The use of the CMC and AC-coupling capacitors for added insulation is the same as previously described, but we suggest slightly different coupling circuitry to damp the multitude of reflections and provide a consistent wave shape for communicating devices irrespective of their physical position in the network. There are three differences: The LTC6820 termination is changed to a 100pF capacitor (CT). Far-end termination is only applied to the live bus (RT) and set to 68Ω (no termination at Fig. 8: Complete high voltage isoSPI bus with echo control. any of the LTC6804-2s). 22Ω coupling resistors (RC) are used for all bus connections to decouple stray capacitive loading. These are shown in the circuit of figure 8, which again assumes the LTC6820 is operating at a safe “earth” potential. The modified waveforms are band-limited to control distortion from reflections, so the received pulses at the IC pins appear more rounded as in figure 9, but the isoSPI pulse discriminator circuit works fine with this filtered shaping and supports a full sixteen address bus. Depending on actual losses encountered in a given system, it may be necessary to lower the pulse-detection thresholds for optimal operation (configure thresholds to be 40%–50% of the differential signal peak). Note that for networks of five or less addresses, the reflections are generally not a significant problem, so standard resistive end-terminations can be retained (namely 100Ω at the CTERM and RTERM positions of Figure 8, with the RCs omitted). Fig. 9: Modified pulse shaping for echo control in isoSPI bus applications. Dual carbon battery charges 20x faster than lithium-ion batteries By Paul Buckley Japanese start -up Power Japan Plus has launched a new battery technology that claims to offer a more sustainable, safer, longer-lasting and cost-effective battery technology with an energy density comparable to a lithium ion battery. The Ryden dual carbon battery makes use of novel chemistry that sees both the anode and the cathode made of carbon. Made of naturally grown organic cotton, the company’s Carbon Complex is claimed to offer novel properties not seen in other carbon materials. By controlling the size of the carbon crystals during production, Power Japan Plus can engineer the Carbon Complex for a variety of high performance applications. The Ryden battery is said to balance a breadth of consumer demands previously unattainable by single battery chemistry, including performance, cost, reliability, safety and sustainability. Energy dense the Ryden battery claims to charge 20 times faster than lithium ion batteries and is also more powerful than other advanced batteries, operating above four volts. The new battery is capable of slotting directly into existing manufacturing processes, requiring no change to existing manufacturing lines. Even more, the battery allows for consolidation of the supply @chain, with only one active material - carbon. Additionally, the manufacture of the Ryden battery would not be subject to supply disruption or price spikes from rare metals, rare earth or heavy metals. Rated for more than 3,000 charge/ discharge cycles, the battery eliminates the unstable active material used in other high performance batteries, greatly reducing fire and explosion hazard. Even more, the battery experiences minimal thermal change during operation, eliminating the threat of a thermal runaway. It can be 100 percent charged and discharged with no damage to the battery. The company is testing the battery with its organic Carbon Complex material, working towards a production with all organic carbon in the future. Power Japan Plus will begin benchmark production of 18650 Ryden cells later in 2014 at its facility in Okinawa, Japan. The facility will allow the company to meet demand for specialty energy storage markets such as medical devices and satellites. For larger demand industries, such as electric vehicles, Power Japan Plus will operate under a licensing business model. 50 Electronic Engineering Times Europe June 2014 www.electronics-eetimes.com


EETE JUN 2014
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