Author: Philip Dost
Co-authors: Carsten Bindig, Constantinos Sourkounis
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BATman is a low power Battery Managment System, which calculates important battery values like state of health, state of charge and state of function. BATman provides the user the opportunity of monitoring the state of the cars battery during the runtime. The measurement parameters voltage and current for calculation are detected by an AS8510 measurement device, which communicates with an Atmel AT32UC3C microcontroller unit (MCU) via SPI. It gets the data with a frequency of 8 kHz for each value. To determine the values a shunt resistor is connected to the battery. The third parameter is the temperature, which is measured with an internal analog digital converter of the MCU. The ADC scales the voltage on a PT100 resistor. The MCU calculates the battery values after getting an interrupt from the measurement device. There are different ways of calculation for the different parameters. The SOC is determined with coulomb counting on one side and about the neutralvoltage on the other side. The SOH is calculated with the internal resistance of the battery. The values are stored in two different sorts of memories. The first memory is a SD-Card for storing data for the user in short time intervals. The second memory is an EEPROM. The EEPROM protects the software parameters in case of supply interruption. The microcontroller communicates with the SD-Card via SPI, too. The communication between EEPROM and controller comes about I2C. The user can access the battery data by connecting to BATman with Bluetooth. The user can set a real time clock which is supported by a 32 kHz oscillator. The Bluetooth IC works as data pump like a serial interface and it is connected with SPI to the microcontroller. For communication with other devices in automotive surrounding BATman includes a CAN communication unit, and allows the integration of LIN as well. An implemented USB socket allows a simplified programing of the MCU with a computer.
Author: Philip Dost
Co-authors: Christoph Degner, Constantinos Sourkounis
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Electromobility is a promising way of locomotion for eco-conscious, future-oriented users. The popularity of electrically powered vehicles increases. Manufacturers offer innovative concepts and promise their customers to reduce the operation and energy costs by buying their products. However, it is difficult to find your way in the growing but still limited supply of vehicles and drive concepts. The Smartphone application described in this article is aimed at those people who have an interest in purchasing an electric or hybrid vehicle, but are not able to verify themselves which kind of car on the market fits to their needs. The application is to help them take their user-specific handling characteristics, to evaluate and to provide an appropriate overview of vehicles from different manufacturers on this basis. The data is recorded during a trip with a conventionally powered vehicle. The app uses the built-in smart sensors and interfaces such as GPS and accelerometer. The data is collected over an individually selected period of time during each trip and allows conclusions on the driving behavior of the user. A recorded track includes altitude, acceleration and velocity profiles which help to estimate the individual energy consumption of each track. By optionally entering charging facilities at the end of each trip it is stated weather and how the vehicle can be charged. After of using the App for several days or even longer, the analysis processes of the data can be performed. The result given is an overview of various electric and hybrid vehicles, which fulfill the energy requirements of previously recorded tracks. The algorithms of the program do not only consider the details of the manufacturer and the declared range by NEDC but also consider inclines, the velocities and the acceleration behavior of the user, which have an impact on the energy demand and thus the range of the vehicle. Thus, the application provides a decision aid, which does not rely only on the static comparison of estimated values, but rely on real measurements and therefore offer individual results.
Author: Manfred Herrmann
Co-authors: Markus Demmerle, Roland Matthé
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Opel bringt das neue Elektrofahrzeug Ampera-e 2017 auf den Markt. Das kompakte Fahrzeug bietet eine sehr grosse elektrische Reichweite von bis zu über 500 km (NEDC) und dynamische Fahrleistungen mit sportlichen Beschleunigungswerten. Das Paper wird den elektrischen Antrieb und die Optimierungsschritte insbesondere bei der Batterietechnologie in der Entwicklung aufzeigen. Dabei werden auch Vergleiche zu vorangehenden Elektrofahrzeugmodellen wie z.B. dem Chevy Spark (erhältlich in USA) aufgezeigt. Die Elektrische Antriebseinheit, bestehend aus permanent erregter elektrischer Synchronmotor, Reduktions-Getriebe sowie Fortschritte des Antriebsumrichters werden im Details vorgestellt. Das Fahrzeug bietet die Möglichkeit zur Wechselstromladung und Gleichstromladung mit dem CCS Ladestecker. Die Schlüsselkomponente der deutlichen Reichweitenerhöhung ist das Batteriesystem im Unterboden des Fahrzeuges. Hier werden die Anforderungen und das Konzept und Design beschrieben: Schnelleres Laden, lange Lebensdauer, hohe klimatische Unterschiede und geringe Kosten, die hier zusätzlich erreicht werden müssen. Weiterhin wird der erreichte Fortschritt der Batterietechnik im Bereich HEV, EREV (PHEV) und BEV und ein Vergleich der System untereinander aufgezeigt. Zum Abschluss werden die erreichten Fahrleistungen des neuen Opel Ampera-e dargestellt.
Author: Dr. Antoni Ferré
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The evolution of complexity in automotive electric/electronic systems for forthcoming autonomous driven vehicles shows the need of re-thinking architectures, specially focused on modularity and scalability for cost-efficient vehicle implementations. In order to build actually safe and secure autonomous driven vehicles, three main aspects need to be considered: firstly, there is a clear demand for enhanced computational capabilities and communications in order to support the real-time execution of more and more sophisticated control algorithms. Secondly, a communication between the autonomous driving cars to the environment like pedestrians and other non-autonomous driving cars is needed. Finally, reliable and ultra-efficient power supply innovations fulfilling the demand of highly available and fail-safe E/E systems should be developed. In this paper, we examine the different trends for future E/E systems and analyze the advantages and disadvantages of each. Also, a possible timing / roadmap is explored.
Lear is one of four suppliers with global capability in providing complete automotive electrical distribution systems for traditional electrical architectures as well as emerging high-power and hybrid systems. We expect electrical content growth in vehicles to be above the rate of industry growth by approximately 5% per year for the foreseeable future reflecting macro industry trends. This content growth will require far more complex vehicle electrical architectures. To succeed in this segment, companies must be able to design and manufacture highly integrated and standardized architectures that optimize size, performance and quality. Software capability will remain a key differentiator due to the increasing complexity resulting from feature content growth and architecture sophistication.
Author: M.Sc. Ziyi Wu
Co-author: Hans Kemper
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– MOTIVATION- Individual batteries have their own operational temperature ranges, which shall be respected to avoid both damaging of the cells and shortening of the cycle life. In terms of the Li-Ion cells, many of them do not function well above 60 °C. Therefore, a better understanding of the thermal behavior of the batteries has its significance during designing safe and robust battery packages for automotive applications. -OBJECTIVE- This study dedicates to analyze the thermal behavior of a 48 V high power battery module for automobile applications and seeks smart solutions for cooling purposes. In order to suppress self-discharge and control the capacity retention of the cells, it’s one of the primary goals to maintain the temperature of all cells not only below the maximal operational temperature, but also below app. 40 °C. The other objective of this study is to minimize the differences in cell temperature aiming at minimizing the differences of the cycle life of cells within the same battery module. -APPROACH- Simulative thermal analysis is employed in this study to gain knowledge of the heating of cells during operational conditions and study the cooling effect of different cooling principles. The study is carried out with following steps: [1] Construction of the battery module in software environment of COMSOL Multiphysics. The construction of the cells and definition of the load profile are derived from the technical data of a suitable candidate for automotive applications. [2] Thermal analysis of the ground model, in which no cooling system is involved. [3] Employment and comparison of different internal cooling fin (ICF) concepts. [4] Employment of external water cooling systems on top of the ground model with one effective ICF concept. [5] Utilization of ICFs and external water cooling systems in a large and densely arranged 48 V battery module. [6] Combination of different cooling systems – ICF and external cooling systems (liquid and air) – to seek for smart solutions. -RESULT- [1] The temperature distribution in the ground model is greatly uneven, which will lead to differences in cell cycle life within the same battery module in the long term and hence a shortened cycle life of the entire module. [2] By involving ICFs, the temperature of the cells stabilizes earlier in comparison to the ground model. [3] By employing one developed ICF concept, the ∆T between the hottest and coldest cell is successfully maintained below 3 K. The temperature of the hottest cell dropped to app. 40 °C at the stable state. [4] By involvement of external water cooling, the ∆T between the hottest and coldest cell is kept below 2 K and the temperature of the hottest cell dropped to below 37 °C at the stable stage. [5] The cooling effect of ICFs and external water cooling systems in the large and densely arranged 48 V battery module is not sufficient. [6] A smart solution – a combination of different cooling principles – is demonstrated in this study to maintain low operational temperatures for all cells and restrict ∆T between the hottest and coldest cell with in the module. -CONCLUSION- Cooling systems for the battery module shall be considered as an indispensable component in high power battery systems for automotive applications. Combined cooling systems with different cooling principles shall be involved for large battery modules, in order to achieve a homogenous temperature distribution and ensure the function of all cells. -ACKNOWLEDGEMENT- The authors are thankful to the Ministry of Innovation, Science and Research of North Rhine-Westphalia for funding this study under the Project “ANFAHRT”.
Author: Dipl-Ing. (FH) Alexander Stadler, Project Management at TÜV SÜD Battery Testing GmbH, Garching, Germany
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BIOGRAPHY
Mr. Alexander Stadler is project manager at the TÜV SÜD Battery Testing GmbH in Garching in Germany. After graduating at Hochschule Karlsruhe he worked for several years at the European Research Organization CERN in Geneva, managing projects concerning the disposal and han-dling of dangerous goods. At TÜV SÜD he is the link between the laboratory and the customer for the whole testing cycle; starting from consulting concerning the applicable standards, through conducting the test series, up to project conclusion.
Today a large variety of test standards and specifications are available in the field of safety vali-dation of xEV batteries. Examples are not only well known standards as UN ECE R100, FMVSS 305 or GB/T 31484 & 31486, but also the underlying standards like IEC 62660-1/2/3 and ISO 12405-1/2/3. Additionally, new methods and tests develop from growing experience with this technology. This presentation will compare various test standards and validation processes, focusing on: •Comparison of test standards and homologation processes in Europe / North America / China •New UN ECE R136 regulation for vehicles of category L •Lessons learned and future developments
Author: Dipl.Ing. Joachim Fröschl
Co-author: Prof. Dr.-Ing. Hans-Georg Herzog
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Moderne Kraftfahrzeugbordnetze zeichnen sich durch eine steigende Vielzahl von elektrischen / elektronischen Systemen zur Darstellung kundenwerter Funktionen aus. Neben der Anzahl der Systeme steigt deren Vernetzung und somit die Komplexität des Gesamtsystems erheblich. Mit der Einführung des kybernetischen Energie- und Leistungsmanagements im neuen BMW 7er wurde die systemische Strukturierung auf ein neues Niveau angehoben. Dieser Beitrag zeigt einen graphischen Ansatz zur Bewältigung der Strukturbeschreibung komplexer Systeme ausgehend von der kybernetischen Grundstruktur des kybernetischen Energie- und Leistungsmanagements. Die Koppelung der Systeme basiert auf drei Ordnungen. Dies sind die Energievernetzung, die Datenvernetzung und die Informationsvernetzung. Beispielhaft wird das kybernetische Modell des Energie- und Leistungsmanagements, aufbauend auf dem Viable System Model VSM von Stafford Beer, in einen Graphen transformiert. Es wird gezeigt, dass diese Graphen in unterschiedlicher Weise mit untereinander gekoppelt werden können. Die Koppelung der Graphen ermöglicht die Modellierung komplexer Systeme. Dabei ist diese Modellierung in ihrem Umfang nicht begrenzt. Zunächst wird das Grundmodell des Energie- und Leistungsmanagements in eine graphische Darstellung gewandelt. Anschließend werden die rekursive Anwendung des Grundmodells und dessen orthogonale Koppelung hergeleitet. In ähnlicher Weise erfolgt die graphische Darstellung der physikalischen Vernetzung und der Datenvernetzung. Die Umweltkoppelung stellt eine Erweiterung der orthogonalen Koppelung dar. Die Ordnungen lassen sich als Graphen vereinigen. Somit lassen sich die Ordnungen der Systemkoppelung als Gesamtgraph, vereinigt aus den Teilgraphen, darstellen. Die Sichtweise auf die hierarchische Ordnung des Gesamtsystems bietet das vorgeschlagene Layermodell. Die Kombination von graphischer Darstellung und dem Layermodell eröffnet die Grundlage für die Bildung von funktionalen Einheiten und Teilbordnetzen. Hierauf aufbauend werden die enthaltenen Wirkgefüge als kybernetische Feedbackstrukturen beispielhaft analysiert. Aus diesen Strukturen ergeben sich zusätzliche Eingriffsmöglichkeiten. Es erfolgt die Diskussion des entstandenen Modells unter den Gesichtspunkten des Systemdesigns und der Migration des graphisch modellierten Systems im Falle einer Änderung, Ergänzung oder im Kontext einer variablen Derivatsausprägung.
Author: Dr.-Ing. Nicolai Tarasinski
Co-author: Julian Daubermann, M.Sc.
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Zur Steigerung von Produktivität und Nachhaltigkeit bei der Feldbearbeitung wird eine autonome Landmaschine vorgestellt, welche über eine elektrische Leitung aus dem Energienetz gespeist wird. Die Energie wird durch speziell entwickelte Mittelspannungstechnik effizient auf das Fahrzeug übertragen. Zur Integration der elektrischen Leitung in den autonomen Arbeitsprozess wird eine Betriebsstrategie vorgestellt und erprobt. Hauptaugenmerk liegt auf der präzisen Positionierung der Leitung auf dem Feldboden durch Regelung der Leitungszugkraft bei einer Fahrgeschwindigkeit von 20 km/h. Auf Grund der Schwingfähigkeit des Systems wird ein Großteil der Dynamik durch Vorsteuerung der Trommeldrehzahl abgebildet um die Anforderungen an die Regelung zu senken. Außerdem ist eine Filterstruktur zur Unterdrückung der Eigenfrequenzen von Fahrzeug und Leitung bei der Messung der Zugkraft vorgesehen.
Author: Matthias Puchta
Co-authors: Franz Dengler, MicroNova AG; Dr. rer. nat. Michael Schwalm, Fraunhofer IWES;
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The most widely used simulations of lithium-ion batteries are based on simple circuit diagrams und characteristics. Such models are only valid in specific ranges under specific operating conditions. For this reason typical challenges like the exact determination of state of charge (SOC) or state of health (SOH) cannot be simulated with the required accuracy. However, in order to be able to calculate realistic vehicle ranges for electric cars it is essential for ECUs to provide exact SOC calculations with respect to the current SOH. Otherwise calculations must be based on worst case assumptions in which the SOC shown is typically worse than the real SOC. The more exact the SOC values are, the more reliable is the possible range displayed for an electric car. Fraunhofer IWES has been working on the exact modeling of batteries for over twenty years. They have knowledge of almost any type of battery. In the last few years, Fraunhofer IWES has developed an electrochemical model for lithium-ion battery cells, the ISET-LIB. This model allows the design and parametrization of batteries and extremely realistic simulation of battery properties, enabling the user to simulate the internal behavior of the battery. All relevant quantities like voltage, temperature, influences of the aging of batteries, and so on can be simulated. A speed-optimized version of the model is available for fast HiL simulations. Because of the high level of details offered by the ISET-LIB, it was not possible to simulate the exact battery cells in the microsecond range. With over 20 years of experience in battery HiL-Simulators, MicroNova has developed a new generation of battery simulation cards that bring the resolution of a battery model down to step times in the range of a few microseconds. In order to achieve this, a number of innovations have been introduced. On the hardware side, all control of the cell simulation card has been made fully digital. In addition, new high-speed, high-precision hardware has been introduced to control cell voltages. This hardware functionality is combined with the Fraunhofer ISET-LIB in an innovative way. The ISET-LIB calculates the long-term behavior of battery cells very precisely every few milliseconds. Additionally, it delivers substitute parameters for the battery (e.g. R,L,C). These parameters are periodically updated in the battery simulation cards that model the short-time behavior. Thanks to this innovative approach, it is possible to achieve the simulation of a high-precision electrochemical battery model with a simulation step width at the microsecond level. Even applications like the simulation of RLC parameters for EIS (electrochemical impedance spectroscopy) are possible with this approach. This new and innovative combination of high-speed HiL and realistic battery simulation for the first time allows the development and testing of future battery functions like EIS and a realistic determination of vehicle ranges.