Electric-controlled pressure relief valve for enhanced safety in liquid-cooled lithium-ion battery packs

The liquid-cooled battery energy sto rage system(LCBESS) has gained significant attention due to its superior thermal management capacity.However,liquid-cooled battery pack(LCBP) usually has a high sealing level above IP65,which can trap flammable and explosive gases from battery thermal runaway and cause explosions.This poses serious safety risks and challenges for LCBESS.In this study,we tested overcharged battery inside a commercial LCBP and found that the conventionally mechanical pressure relief valve(PRV) on the LCBP had a delayed response and low-pressure relief efficiency.A realistic 20-foot model of an energy storage cabin was constructed using the Flacs finite element simulation software.Comparative studies were conducted to evaluate the pressure relief efficiency and the influence on neighboring battery packs in case of internal explosions,considering different sizes and installation positions of the PRV.Here,a newly developed electric-controlled PRV integrated with battery fault detection is introduced,capable of starting within 50 ms of the battery safety valve opening.Furthermore,the PRV was integrated with the battery management system and changed the battery charging and discharging strategy after the PRV was opened.Experimental tests confirmed the efficacy of this method in preventing explosions.This paper addresses the safety concerns associated with LCBPs and proposes an effective solution for explosion relief.

Effect of Dynamic Pressure Feedback Orifice on Stability of Cartridge-Type Hydraulic Pilot-Operated Relief Valve

Current research on pilot-operated relief valve stability is primarily conducted from the perspective of system dynamics or stability criteria,and most of the existing conclusions focus on the spool shape,damping hole size,and pulsation frequency of the pump.However,the essential factors pertaining to the unstable vibration of relief valves remain ambiguous.In this study,the dynamic behavior of a pilot-operated relief valve is investigated using the frequency-domain method.The result suggests that the dynamic pressure feedback orifice is vital to the dynamic characteristics of the valve.A large orifice has a low flow resistance.In this case,the fluid in the main spring chamber flows freely,which is not conducive to the stability of the relief valve.However,a small orifice may create significant flow resistance,thus restricting fluid flow.In this case,the oil inside the main valve spring chamber is equivalent to a high-stiffness liquid spring.The main mass-spring vibration system has a natural frequency that differs significantly from the operating frequency of the relief valve,which is conducive to the stability of the relief valve.Good agreement is obtained between the theoretical analysis and experiments.The results indicate that designing a dynamic pressure feedback orifice of an appropriate size is beneficial to improving the stability of hydraulic pilot-operated relief valves.In addition,the dynamic pressure feedback orifice reduces the response speed of the relief valve.This study comprehensively considers the stability,rapidity,and immunity of relief valves and expands current investigations into the dynamic characteristics of relief valves from the perspective of classical control theory,thus revealing the importance of different parameters.

SUPPRESSION OF A CAVITATION NEAR THE ORIFICE OF A RELIEF VALVE

The aim of this study is to suppress a cavitation near the orifice of arelief valve by changing the shape of a poppet. An experimental flow visualization technique and anumerical cavitating flow simulation, using a RNG kappa-epsilon turbulence model and a cavitationmodel, are employed to achieve the purpose. In the flow visualization, the cavitation phenomenonnear the orifice of a relief valve is observed using a transparent test valve body model and acamera. On the other hand, a three dimensional cavitating flow simulation is conducted to predictthe cavitation near the orifice of a relief valve. Six types of poppets are designed by changing theshape of a traditional poppet shape, which is expected to influence the cavitating flow in anorifice. In addition, the cavitation noise of a relief valve is measured and the noise spectrum isanalyzed. In conclusion, the cavitation intensity and the cavitation noise are reduced for anoptimal poppet geometry obtained in the present study.

DESIGN THEORY FOR G-π BRIDGE RELIEF VALVE WITH ZERO OVERRIDE

A new construction of the relief valve is presented with pilot G-pi bridghydraulic resistances network. The design theory of G-pi bridge relief valve is studied and theformulas for designing the relief valve with zero static pressure override are obtained. The staticperformances of the relief valve are experimentally investigated. The theoretical and experimentalresults show that the static pressure override of the developed relief valve can be zero, i.e. whenthe overflow increases the control pressure is kept constant.

The optimum design of the pressure control spring of the relief valve based on neural networks

Based on the traditional optimization methods about the pressure control spring of the relief valve and combined with the advantages of neural network, this paper put forward the optimization method with many parameters and a lot of constraints based on neural network. The object function of optimization is transformed into the energy function of the neural network and the mathematical model of neural network optimization about the pressure control spring of the relief valve is set up in this method which also puts for ward its own algorithm. An example of application shows that network convergence gets stable state of minimization object function E, and object function converges to the utmost minimum point with steady function, then best solution is gained, which makes the design plan better. The algorithm of solution for the problem is effective about the optimum design of the pressure control spring and improves the performance target.

PRESSURE COMPENSATION METHOD OF UNDERWATER HYDRAULIC SYSTEM WITH HYDRAULIC POWER UNIT BEING UNDER ATMOSPHERIC CIRCUMSTANCE AND PRESSURE COMPENSATED VALVE

Based on the analysis of the-state-of-the-art of pressure compensation of underwater hydraulic systems （UHSs）, a new method of pressure compensation of UHSs, whose hydraulic power unit is in the atmospheric circumstance, is proposed. And a pilot-operated relief valve with pressure compensation is realized. The pressure compensation precision is guaranteed by direct detection. Its dynamic performance and stability are improved by a dynamic feedback. Theoretical study, simulation and experiment show that the pilot-operated relief valve with pressure compensation has a fine property of tracking underwater ambient pressure and meet the requirement of underwater ambient pressure compensation.

博世共轨压力泄压阀打开故障解析

文章主要对泄压阀的结构原理、故障发生机理进行系统介绍,并结合故障诊断与排除思路进行说明,以期能够为维修人员提供一些启发和帮助。

振动环境下直动式溢流阀的防压力波动可靠性分析

液压装备工作环境复杂,其中不乏存在振动、冲击等不利因素,这些因素与不确定性因素耦合极易引起溢流阀调定不当从而造成液压装备失效。针对此问题,考虑不确定性因素的影响,提出了一种直动式溢流阀防压力波动可靠性分析模型。通过适当简化建立了溢流阀在振动环境下的数学模型,并以调定压力波动幅值是否超过国标规定值为判别条件,构建了溢流阀压力波动失效的功能函数。考虑到功能函数为强非线性隐式,将MATLAB/Simulink仿真与主动学习Kriging模型相结合建立溢流阀防压力波动可靠性分析方法,并得到了振动环境下溢流阀压力波动失效概率。所得结果不仅为溢流阀的可靠性评估和设计优化提供了新的指导,还对发展液压相关元件可靠性技术具有一定的学术价值。

液压振动试验台直动式溢流阀异常泄露分析及优化

针对振动试验台测试时产生的振动影响直动式溢流阀异常泄露问题,通过建立振动环境下阀芯开口量数学模型,并结合MATLAB及控制变量法,分析振动与元件结构参数对泄漏量的影响规律。在研究各影响因素的基础上,以最小泄漏量为目标函数,基于遗传算法对溢流阀异常泄露影响因素进行优化,从而得到稳定性较高的试验台。优化结果显示:在满足各因素变化范围内经优化后,振动频率、振幅、质量分别下降35.25%、30.7%、18.75%;溢流阀弹簧刚度、粘性阻尼系数分别提升28.59%、30.85%,可使得异常泄漏量减少96.98%;所得结果为振动试验台设计及溢流阀结构优化提供重要参考理论依据。

高速开关阀先导驱动高水基大流量比例调速阀的设计与仿真

在智能综采工作面生产工程中,液压支架在移架和推溜的过程中经常会遭遇不稳定负载,传统开关式的电液控制元件无法对推溜油缸进行速度调控,导致推溜油缸位置控制困难,影响了刮板机的调直度,从而制约了智能综采装备的应用效率。针对这一问题,考虑到煤矿乳化液介质低黏度、润滑性差等特征,设计了一种高速开关阀作为先导阀的高水基高压大流量比例调速阀,建立了阀的数学模型,根据调速阀的内部结构及工作原理建立其AMESim仿真模型,对影响节流阀阀芯位置闭环控制特性、调速阀压差-流量特性进行仿真分析。仿真表明,A型先导液桥对主阀芯的响应具有更好的性能,主阀下控制腔容积、复位弹簧刚度对阀芯的响应速度、稳定性有一定影响。总体而言,调速阀具有较好的流量调节刚度,功能和性能达到了预期设计要求。

复合磁-电弹簧直动式溢流阀设计与性能分析

为了解决传统机械弹簧因塑性变形、断裂等造成溢流阀工作性能劣化的问题,设计一种复合磁-电弹簧结构应用于直动式溢流阀调压弹簧中,以提高直动式溢流阀的响应速度,实现电控弹簧力。理论分析复合磁-电弹簧磁力特性,利用Maxwell软件对复合磁-电弹簧进行磁力特性仿真;采用AMESim软件对机械弹簧直动式溢流阀和复合磁-电弹簧直动式溢流阀进行动态特性仿真。对复合磁-电弹簧磁力特性及溢流阀的动态特性进行实验测试。结果表明:复合磁-电弹簧设计合理,复合磁-电弹簧直动式溢流阀动态响应特性优于现有机械弹簧直动式溢流阀。

双膛石灰竖窑粉尘排放特性及控制技术研究

分析了石灰双膛竖窑在泄压过程中的粉尘排放特性,初始冲击波压力过高导致烟气无法直连布袋除尘器,这是造成粉尘污染的主要原因。弄清了初始冲击波的形成、传播与演化行为特征,比对了延长直管长度、增加弯管数量、增加变径结构与泄压腔体三种方式对冲击波压力的衰减效果,提出了一种基于压块泄压阀的柔性泄压直联布袋技术,将放散烟气初始冲击波压力由8 kPa降至1 kPa,达到烟气直连布袋、环境粉尘污染得到大幅改善的效果。同时,针对粉尘在阀体和管道中易沉降的难题,提出了一种基于3通内旋阀的扇形旋塞防沉降技术,解决了粉尘在阀体与管道系统内的沉降难题。

自动垂直钻井工具纠斜液压系统的研究

对一种用于石油自动垂直钻井工具的纠斜液压系统展开研究,以实现钻具的纠斜力稳定、可变及钻具矢量纠斜效果。针对油缸压力无法调节及液压泵引起油缸压力不易稳定的问题,研究一种新型纠斜液压系统。在建立纠斜液压系统数学模型的基础上,进行了系统和油缸压力的动态响应分析。仿真结果表明,新型纠斜液压系统提供的导向推力较传统系统稳定性更高,压力波动幅度更低;调节比例溢流阀的输入电流55~85 mA,并保持比例溢流阀输入电流增量不变,钻杆转速越大,油缸压力在单位时间内的开环调节精度就越高。

恒力磨床液压控制系统研究

为提高某恒力磨床设备的压力精度,增加对位置偏差干扰的抵抗能力,根据设备输出数据指标设计研究液压控制系统。根据设计的液压原理图在AMESim仿真软件中完成系统仿真建模,进行闭环压力控制系统分析研究,最终采用前馈补偿与压力闭环反馈结合的复合PID控制方案,具有最佳控制效果,并能够实现在工作过程中遇到位置偏差时具有一定抗干扰能力,保证输出精度在目标压力精度范围内。

一种补油溢流阀压力超调特性分析及结构参数优化

带有活塞杆控制的先导式带补油功能溢流阀具有响应快、通流量大等特点,在工程机械液压系统中应用广泛,但压力超调量较大。为了揭示影响压力超调量的关键因素,以某型先导式补油溢流阀为研究对象,利用AMESim搭建仿真模型,研究其结构参数对压力超调的影响规律。仿真表明:当主阀芯半锥角、先导阻尼孔径和进油口直径逐渐增大时,其主阀口压力超调量均逐渐减小;当阀芯阻尼孔径逐渐增大时,其主阀口压力超调逐渐增大;当主阀芯半锥角、阀芯阻尼孔径、先导阻尼孔径以及进油口直径分别从25°,4.2 mm,4.10 mm,13.0 mm调整为40°,4.8 mm,4.16 mm,13.5 mm时,其主阀口压力超调量从57.1%降至19.4%,结构参数优化后的补油溢流阀超调较之前有显著降低。此外,改进后的补油溢流阀在补油工况下开启压力0.13 MPa,压差随补油流量增加缓慢,性能较之前相比有较大的提升。为阀的优化提供理论指导,并且对同类型产品的相关研究有一定的参考价值。

插装式溢流阀校验用接头设计

结合插装式溢流阀结构特点、使用工况以及安全阀校验装置特点,根据校验用规程和标准要求,设计了一种插装式溢流阀校验用接头。采用插装式溢流阀和校验装置对接头进行性能检测。结果表明:该接头满足校验工艺要求,并能精准校验插装式溢流阀的整定压力和密封性。

供氮气源装置膜片式泄压阀异常打开原因分析

介绍了某供氮气源膜片式泄压阀异常打开原因的排查过程,分析可能造成泄压阀异常打开的原因,并针对可能原因进行试验验证和排查,通过气候模拟、能谱对源区成分分析等方法,对排查中发现的具体问题进行具体分析,最终发现故障原因并得出结论。

蒸汽安全阀仿真分析与结构优化

采用ANSYS CFX流场仿真技术对优化后的锅炉管道用蒸汽安全阀流场排量和升力系数进行研究。结果表明:结构优化后的蒸汽安全阀开高设计合理,具有较好的排放性能,临界压力比在0.400~0.497之间,流阻损失小。阀瓣结构优化后,升力曲线得到改善,能够迅速达到设计开高要求,及时排放压力,减少颤振等问题的发生。

液压油箱卸压活门三参数威布尔寿命分布灰色建模

针对三参数威布尔分布参数估计的难题,提出一种三参数威布尔分布参数的灰色估计方法。基于某型液压油箱卸压活门使用阶段的随机截尾型可靠性数据,采用GM(1,1)估计三参数威布尔分布模型的参数。结果表明:应用灰色模型GM(1,1)能够估计出三参数威布尔分布的3个参数,避免了迭代过程,具有求解速度快、所需子样少、精度高、计算机编程方便等优点,同时也验证了三参数威布尔分布模型比两参数威布尔分布模型更为精确,可为武器装备在使用阶段提供一种更为精确的可靠性分析方法。

基于AMESim的高压溢流阀特性分析

先导式高压溢流阀作为轴向柱塞变量泵或轴向柱塞变量马达的安全阀,其工作性能将直接关系到轴向柱塞变量泵、轴向柱塞变量马达及系统的安全性与可靠性。针对某型高压溢流阀,对其进行工作原理介绍以及数学计算,并通过AMESim建立仿真模型,探究节流孔直径、先导弹簧预紧力和主阀弹簧预紧力对高压溢流阀的开启压力、压力超调量、压力超调稳定时间及卸荷时间的影响,对高压溢流阀的设计具有指导意义。