论文电池监测和电能管理先决条件未来汽车电力系统（英文版）.doc

Journal of Power Sources 116 (2003) 7998Battery Monitoring and Electrical Energy ManagementPrecondition for future vehicle electric power systems电池监测和电能管理 先决条件，未来汽车电力系统Eberhard Meissner*, Gerolf RichterVARTA Automotive, Vehicle Electric Systems & System Development, P.O. Box 210 520, D-30405 Hannover, GermanyAbstractNew vehicle electric systems are promoted by the needs of fuel economy and ecology as well as by new functions for the improvement of safety and comfort, reliability, and the availability of the vehicle. Electrically controlled and powered systems for braking, steering and stabilisation need a reliable supply of electrical energy.The planned generation of electrical energy (only when it is economically beneficial meaningful), an adequate storage, and thrifty energyhousekeeping with an intelligent integration of the battery as the storage medium into the overall concept of the vehicle Energy Management, and early detection of possible restrictions of reliability by Battery Monitoring allows for actions by the Energy Management well in advance, while the driver need not be involved at all.To meet todays requirements for Battery Monitoring and Energy Management, solutions have been developed for series vehicles launchedin years 20012003, operating at the 14 V level.# 2003 Elsevier Science B.V. All rights reserved.Keywords: Automotive battery; SLI; Vehicle electric power system; Battery Monitoring; State-of-charge (SOC); State-of-health (SOH); BatteryManagement; Energy Management摘要 新系统的推广电动车辆的燃油经济性和生态的需要，以及由为安全和舒适性，可靠性和车辆的实用性改进的新功能。电控和动力制动，转向和稳定系统需要一个可靠的电能供应。 电能的（只有当它在经济上是有益的有意义）计划的产生，一足够的存储，节约能源和 家政与本电池作为存储介质将车辆能源管理整体概念智能集成，可靠性和可能的限制由电池监测早期检测由能源管理行动提前做好允许，而司机不必在所有参与。 为了满足电池监测和能源管理今天的要求，解决方案已制定了一系列的车辆推出 在2001-2003年，在14 V的水平运行。 2003 Elsevier科学B.诉保留所有权利。 关键词：汽车电池，SLI技术，车辆电力系统，电池监测;国家的主管（SOC）的，国家的健康（希望之声）;电池 管理，能源管理 显示对应的拉丁字符的拼音1. IntroductionThe term Battery Monitoring is used in a wide range of meanings, from occasional manual readings of voltages, of electrolyte gravity SG and level, and visual cell inspection, through periodical tests of capacity or manual measurement of battery resistance, to fully automated on-line supervision in critical applications with means for real-time estimation of residue bridging time, or of battery wear and tear.In this paper, the term Battery Monitoring is used for supervision without manual engagement, which is state-of- the-art with many cycling batteries in automatically guided vehicles (AGVs), forklift trucks, submarines, electrically driven cars and trucks, as well as with standby batteries in telecom and UPS applications. With consumer applica- tions, any mobile phone, laptop or pocket computer, or evena wristwatch is equipped with a device providing some information with respect to energy being left.Classical industrial cycling applications and many con- sumer devices are characterised byperiodical complete recharge, providing a well-defined reset to full state-of-charge (SOC),* Corresponding author. Tel.: þ49-511-975-2410.discharge starting from full SOC, until either the battery isexhausted or duty is completed,scarcely any recharge without reaching full SOC level(opportunity charge), andsingle type of discharge duty only to provide power for an application characterised by limited range of discharge and recharge current rates, and operation temperatures.Periodical reset to full SOC allows for regularly re- calibration, and in the rare cases when recharge was unti- mely interrupted, some loss of precision may be acceptable. Discharge starting from a well-defined battery status with a limited variety of current rates and profiles facilitates track- ing of battery status.More difficult is the situation with stationary batteries operated together with solar or wind energy plants. While some of the characteristics mentioned above facilitate Battery Monitoring, as with traction batteries, full SOC is scarcely reached, because sizing of components and operational strategy aim at never reaching the extremes of the operating window in order to make optimum use of the solar and wind power potentially offered. Therefore, tracking of operational history to evaluate the actual battery condition is difficult due to the accumulation of measuring inaccuracies.0378-7753/03/$ see front matter # 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0378-7753(02)00713-980E. Meissner, G. Richter / Journal of Power Sources 116 (2003) 7998When compared with these two types of operation, thespecific different situation of automotive batteries becomes obvious, technically impeding Battery Monitoring in the automotive fields:They are scarcely ever been completely charged, i.e.opportunity charge is standard.Recharge is performed with a wide range of different current rates.Discharge virtually never starts from a full SOC. Discharge is performed with a wide range of different current rates.Sometimes full discharge or (unfortunately) even over-discharge occurs.A large variety of electric duties must provide power for may different applications.Operational temperature may even exceed the window from30 to 70 8C.In addition, the automotive cost level excludes many solutions which may be acceptable in other fields.While the term Battery Monitoring comprisestaking and/or receiving data from and/or about the battery, processing of this information, including predictions of performance, andindicating raw data or processed information to a human being or a unit, i.e. only passive surveillance and evaluation,the term Battery Management means active feedback to the battery. This may comprise control of current or voltage levels, control of recharge conditions, limiting of the opera- tional windows with respect to SOC and/or temperature, battery temperature management, etc.Energy Management (Electrical) means housekeeping with the electrical energy, i.e. control of energy generation, flow, storage, and consumption. Without the essential informa- tion from Battery Monitoring, Energy Management may scarcely work. An appropriate Battery Management may significantly enhance and improve, but is not a precondition for, a successful Energy Management. Fig. 1 sketches the layer structure of Battery Monitoring generating Battery Status Information, Battery Management, and Energy Management.Fig. 1. Layer structure of Battery Monitoring generating Battery Status Information, Battery Management, and Energy Management, and mutual data flow.It is Energy Management, preferably including BatteryManagement, which, based on the information from Battery Monitoring, allows for a self-standing operation of a system without manual inputthe comfort and the technical neces- sity requested for a vehicle at the beginning of the 21st century.2. Changes in electric systems and the drivers for these changesVehicle electric power systems are driven more and more by the needs of fuel economy and ecology as well as by new functions for the improvement of safety and comfort. New components may improve comfort and reliability, and the availability of the vehicle. In many cases, there is potential to reduce production and operational cost. Electrically con- trolled and powered systems for braking, steering and stabilisation need a reliable supply of electrical energy. Possible restrictions of reliability have to be prevented by the Energy Management and evaluated in advance, while the driver need not be involved at all.Reduction of fuel consumption is expected to be achieved by replacement of mechanically driven auxiliary compo- nents by electrical components, which are been activated only when they are needed, and higher energy efficiency with generation, distribution, and use of electrical energy. While these goals are aiming at improvements of electrical engines, energy transfer and design of the electrical con- sumers, an important contribution can also be given by the planned generation of electrical energy, an adequate storage, and a thrifty energy housekeeping. Electric energy has to be generated when it is economically beneficial, and stored until it is needed in periods when generation is either inefficient or not possible at all.This means an intelligent integration of the battery as the storage medium into the overall concept of the vehicle Energy Management. Careful monitoring and control of energy flows allows for minimum investment with respect to cost, weight and volume.The overall requisite electrical performance is increas-ingwith much higher fluctuations of the load demand than today. This cannot be covered by simple scaling up of todays components. Procedures are needed for optimal use of the battery resource: knowledge of actual state-of- charge, power capability, and degradation of the battery as an input for Energy Management.2.1. The automotive battery in the pastIn the beginning of the development of road vehicles driven by an internal combustion engine (ICE), there was no electrical equipment at all on board of the vehicle besides the ICE ignition, realised by magneto ignition ormore reli- ablyby primary dry cells. Lighting of luxury cars was soon provided electrically by storage batteries. But it was as lateE. Meissner, G. Richter / Journal of Power Sources 116 (2003) 799881as 1912 that the first electrical starter motor was used in aseries production car. This displacement of the cranking lever by a battery-driven electrical starter motor helped the combustion engine make the final breakthrough as the source of power for road vehicles.In view of the fact that the start routine is a very short one, both components, battery and starter motor, have, over the years, undergone a complete optimisation to obtain the best possible torque for the lowest possible manufacturing costs. The further development of the vehicle electrical system was favoured by the fact that increasingly powerful (claw- pole type) alternators became available at ever-decreasing manufacturing costs, and the vehicle battery, which was repeatedly called upon to provide cold starting power, was able to deliver some energy at all times to cover electrical requirements even during periods when the power supply to consumers was inadequate.The dc alternators suffered from low or even no power output at low revs, so the battery had to provide electric power not only when the engine was at rest, but also when it was on idle. This was not an issue for decades, as electrical ignition, lighting and windscreen-wipers were the only consumers, and features like radio and electrically driven fans were limited to upper-class vehicles. In the 1960s, the automotive industry countered a major electrical energy bottleneck, caused by the rapid rise in the number of electrical consumers installed, esp. the introduction of the electrical window defroster, by doubling the battery voltage to 12 V and introducing an adapted 14 V three-phase ac alternator.2.2. The automotive battery in present vehiclesThis technical concept is unchanged to the present day. Fig. 2 shows voltage and current measured during cranking of a high-end engine at ambient temperature. The engine is running within about 100 ms. Even at low temperature, a modern car ICE is running within some secondsor will not crank at all.In classical vehicles, the battery is a completely passive energy and power storage device:Fig. 2. Voltage and current measured during cranking of a high-end gasoline engine at ambient temperature.it is discharged if more energy is consumed than gener-atedwithout any check if the battery is able to give this energy (in a meaningful way), andenergy for recharge is offered to the battery if more energy is available than is actually needed without any check if the battery is able to take the energy.This so-called partial state-of-charge (PSOC) operating mode is standard for SLI batteries since decades. Typical SOC levels are about 90% after an extended highway drive in summertime, down to less than 50% in a traffic jam condition in wintertimeor even much less, which may generate cranking problems when the engine is switched off in this state.The actual recharge voltage at the battery terminals depends on the actual alternator voltage and on the Ohmic losses at their connection, according to the current flowing to or from the battery or to other components. This may reduce the battery recharge voltage by several 100 mV compared to the alternator output voltage as can be measured with upper- class vehicles with the battery mounted in the trunk. Even ifa temperature-dependent voltage regulator is used, this is mounted near to the alternator, and does not care about the battery temperature which may still be low for hours when the alternator is already at operational temperature.There is no control of recharge current, and the state-of- charge of the battery is a scarcely predictable function of electrical loads, driving conditions, alternator, and regulator properties, and battery properties including size, design, temperature, and battery ageing.The measured voltage versus current profile (the situation is given in Figs. 7 and 8 in 1) shows a hysteresis-like behaviour, as the SLI battery is alternately discharged and recharged. The voltage level and the duration of the periods of discharge and charge, depend on the operating conditions as well as on the layout of the system and the battery properties, cf. 1,2.The electrical system, comprising the alternator as the source of current, the battery as current storage device, and the consumers, is designed in such a way that the combina- tion of driving conditions (which determine the possible generation of current by the alternator according to the rpm- profile) and the expected mix of operation of various con- sumers (which determines the current consumption) pro- vides the current not only in the long-term time average, but also over short periods of time.Thanks to significant improvements of power supply even at low and idle speed of the ICE by improved characteristics and higher efficiency of the alternator, current generation by the alternator is suf