Research On High Voltage Characteristics Of Pulse Energy Capacitor Energy Storage Ceramic Materials

In recent years,with the rapid development of new concept weapons such as high-energy weapons and laser weapons,the high-power output of pulse power system is getting higher and higher.Pulse power system is the core of the entire system.It will decide whether the system is strong enough to meet the shipboard,and even the key to the requirements of the airborne.The energy storage module is the most important pulse power system.Pulse power capacitors with high power density,charge and discharge speed,wide temperature and frequency range,in a sense,is the most practical,low cost,and easy to achieve industrial application.The only bottleneck is a lower energy storage density?1 J/cm³?.In this paper,the energy storage density and power density test system of high voltage pulse power devices are established.The Ba TiO₃ system,the PLZST system of antiferroelectric materials and the TiO₂ system of linear media are the most promising materials.The influencing factors and solutions of energy storage density are analysed.And through the energy storage media MLCC process compatibility research,the properties of the device are exhibited.The details are as follows:1.For the BaTiO₃ system ferroelectric materials,the dielectric constant at high pressure is greatly reduced,and the enhancement of effective polarization?effective polarization=maximum polarization-remnant polarization?and the regulation of ferroelectric phase are used to suppress high voltage nonlinearity,for improve energy density.In order to enhance the effective polarization,the A and B sites of the BaTO₃system were doped with BiMO₃?M=Al,In,Y,Sm,Nd,La?and the original long-range polarization was interrupted to form a new weak coupling,which could produce relaxation characteristics and suppress high-voltage non-linearity,for enhancing the energy storage density.The different elements such as BiYO₃ and BiIn O₃ were studied systematically.When the element M=In,the energy storage density reached 0.753 J/cm³,which was 3.43 times higher than that of pure BaTiO₃,and the efficiency was 89.4%.In the regulation of ferroelectric phase,MNbO₄ was used as dopant.The doping of Nb⁵⁺can reduce the Curie temperature which led to form paraelectric phase,for improving the high voltage linearity.The influence of different Bi/Nb ratio,different sintering system and different trivalent element M doping on its energy storage performance were studied systematically.When the doping element M=Bi,and the amount of doping BiNbO₄=10%,the storage density reached 0.797 J/cm³,which was 3.69 times higher than that of pure BaTiO₃,and the efficiency was 92.5%.2.Because the dielectric constant of the PLZST system increased with the increase of the electric field,we introduced the coupling polarization for increasing the dielectric constant and adjusted the phase transition electric field to improve the energy storage density.The BiYO₃ doping was used to interrupt the original long-range polarization,and the new coupling polarization was established to enhance the dielectric constant,resulting in improved energy storage density.When the doping amount was 1%,the energy storage density reached 0.68 J/cm³,which is 1.26 times higher than that of pure PLZST,and the efficiency was 86.1%.On the other hand,the use of BiNb O₄ as a donor doping,interrupted the original long-range polarization,the establishment of new coupling polarization,adjusted the phase transition electric field,enhance the effective energy storage density.When the doping amount was 1%,the energy storage density reached 0.82 J/cm³,which is 1.72 times higher than that of pure PLZST,with the maximum efficiency of 88%.3.Due to the low voltage and low dielectric constant of the TiO₂ medium with linear medium,this paper improves the energy consumption density by improving the voltage or dielectric constant with the combination of insulating glass,defect balance and the introduction of defective dipole.First,the effect of different titanium source,different insulating glass and different synthetic methods on the energy storage characteristics of the composites was studied by using the idea of composite with insulating glass.When the nano-rutile TiO₂ was used as the titanium source,the glass/TiO₂ composite material prepared by the sol-gel method achieved the highest energy storage characteristic of Ba-B-Al-Si glass,1.92 J/cm³,which was 1.74 times higher than that of pure TiO₂.Second,we used the Mn doping for reducing the oxygen vacancy,and used the two-step sintering to suppress grain size to improve the density.TiO₂ with 0.05%Mn sintered by the two-step sintering process 1.75 J/cm³,which was1.5 times higher than that of pure TiO₂.Third,the use of Al+Nb combination doping induced the defective dipole,exhibiting a substantial increase in dielectric constant.When Al/Nb=1 and the co-doping ratio is 5%,the dielectric constant was as high as1997,which was nearly 20 times higher than that of pure TiO₂ and the loss was less than 5%from 100Hz to 1MHz.4.In order to meet the batch production methods,several groups of formulations were optimized for casting process,optimizing the slurry formulation,adjusting the stacking,printing,isostatic pressing and other process parameters to prepare single and multi-layer capacitors.The results showed that the MLCC electrode of different materials had good co-firing and no obvious diffusion phenomenon.And use the self-built energy storage characteristics of the test platform to measure the high-voltage DC charge and discharge characteristics.The energy storage density of the MLCC with8 layers and 135 nF achieves 4.64 J/cm³;When the constant charging voltage was 700 V,the instantaneous discharge current peak reaches 1180 A and the pulse width was 500 ns,which had reached the advanced level of application in a special field.