Power Batteries Health Monitoring: A Magnetic Imaging Method Based on Magnetoelectric Sensors.

With the popularity of electric vehicles, the ever-increasing demand for high-capacity batteries highlights the need for monitoring the health status of batteries. In this article, we proposed a magnetic imaging technique (MIT) to investigate the health status of power batteries nondestructively. This technique is based on a magnetic sensor array, which consists of a 16-channel high-performance magnetoelectric sensor, and the noise equivalent magnetic induction (NEB) of each channel reaches 3-5 pT/Hz1/2@10 Hz. The distribution of the magnetic field is imaged by scanning the magnetic field variation of different positions on the surface. Therefore, the areas of magnetic anomalies are identified by distinguishing different magnetic field abnormal results. and it may be possible to classify the battery failure, so as to put forward suggestions on the use of the battery. This magnetic imaging method expands the application field of this high-performance magnetoelectric sensor and contributes to the battery's safety monitoring. Meanwhile, it may also act as an important role in other nondestructive testing fields.

A Two-Step Annealing Method to Enhance the Pyroelectric Properties of Mn:PIMNT Chips for Infrared Detectors.

Mn:0.15Pb(In1/2Nb1/2)O3-0.55Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 (Mn:PIMNT) pyroelectric chips were prepared by a two-step annealing method. For the two steps, annealing temperatures dependence of microstructure, defects, surface stress, surface roughness, dielectric properties and pyroelectric properties were studied comprehensively. The controlling factors influencing the pyroelectric properties of the Mn:PIMNT crystals were analyzed and the optimum annealing temperature ranges for the two steps were determined: 600-700 °C for the first step and 500-600 °C for the second step. The pyroelectric properties of the thin Mn:PIMNT chips were significantly enhanced by the two-step annealing method via tuning oxygen vacancies and eliminating surface stress. Based on Mn:PIMNT pyroelectric chips annealed at the most favorable conditions (annealed at 600 °C for the first step and 500 °C for the second step), infrared detectors were prepared with specific detectivity D* = 1.63 × 109 cmHz1/2W-1, nearly three times higher than in commercial LiTaO3 detectors.

Broadband and high sensitive time-of-flight diffraction ultrasonic transducers based on PMNT/epoxy 1-3 piezoelectric composite.

5-6 MHz PMNT/epoxy 1-3 composites were prepared by a modified dice-and-fill method. They exhibit excellent properties for ultrasonic transducer applications, such as ultrahigh thickness electromechanical coupling coefficient k(t) (85.7%), large piezoelectric coefficient d33 (1209 pC/N), and relatively low acoustic impedance Z (1.82 × 107 kg/(m2·s)). Besides, two types of Time-of-Flight Diffraction (TOFD) ultrasonic transducers have been designed, fabricated, and characterized, which have different matching layer schemes with the acoustic impedance of 4.8 and 5.7 × 106 kg/(m2·s), respectively. In the detection on a backwall of 12.7 mm polystyrene, the former exhibits higher detectivity, the relative pulse-echo sensitivity and -6 dB relative bandwidth are -21.93 dB and 102.7%, respectively, while the later exhibits broader bandwidth, the relative pulse-echo sensitivity and -6 dB relative bandwidth are -24.08 dB and 117.3%, respectively. These TOFD ultrasonic transducers based on PMNT/epoxy 1-3 composite exhibit considerably improved performance over the commercial PZT/epoxy 1-3 composite TOFD ultrasonic transducer.

Fabrication of a PMN-PT single crystal-based transcranial Doppler transducer and the power regulation of its detection system.

Doppler sonographic measurement of flow velocity in the basal cerebral arteries through the intact skull was developed using a pulsed Doppler technique and 2 MHz emitting frequency. Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) were chosen to be the piezoelectric transducer material due to their ultrahigh piezoelectric coefficients, high electromechanical coupling coefficients and low dielectric loss. The pulse-echo response of the transducer was measured using the conventional pulse-echo method in a water bath at room temperature. The -6 dB bandwidth of the transducer is 68.4% and the sensitivity is -17.4 dB. In order to get a good match between transducer and detection system, different transmission powers have been regulated by changing the impedance of the transmitting electric circuit. In the middle cerebral artery (MCA) measurement photograph results, as the transmission power is increasing, the detection results become clearer and clearer. A comparison at the same transmission power for different transducers shows that the detection photograph obtained by the crystal transducer was clearer than that obtained with a commercial transducer, which should make it easier for doctors to find the cerebral arteries.

Scale effects of low-dimensional relaxor ferroelectric single crystals and their application in novel pyroelectric infrared detectors.

Scaling effects of low-dimensional relaxor ferroelectric single crystals have induced large delocalization of domain switching, leading to a dramatic increase in pyro-electric performances by 2-5.5 times, and promoting the detectivity of fabricated pyroelectric detectors to an international leading level of 2.21 × 10(9) cmHz(1/2) /W at 10 Hz, 4 times higher than that of commercial LiTaO3 -based detectors.

Piezoelectric energy harvesting based on shear mode 0.71Pb(Mg(1/3)Nb(2/3))O3-0.29PbTiO3 single crystals.

In this paper we theoretically and experimentally present a nonresonant vibration energy harvesting device based on the shear mode of 0.71Pb(Mg(1/3)Nb(2/3))O3-0.29PbTiO3 single crystals. The electrical properties of the energy harvesting device were evaluated using an analytical method. Good consistency was obtained between the analytical and experimental results. Under a mass load of 200 g, a peak voltage of 11.3 V and maximum power of 0.70 mW were obtained at 500 Hz when connecting a matching load resistance of 91 komega. A high output could always be obtained within a very wide frequency range. The results demonstrate the potential of the device in energy harvesting applied to low-power portable electronics and wireless sensors.