Author: Uwe Beher
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Neuartige auf dem Markt verfügbare Leistungshalbleiter ermöglichen aufgrund der geringen Schalt- und Bahnverluste neuartige Ansätze für das Design von DCDC-Wandlern für Batteriespeicher. Hierzu zählen insbesondere GaN-Transistoren, die mit den Nennspannungen von 100V und 600V im Fahrzeug sowohl auf der Hochvolt- als auf der Niedervoltebene ein-gesetzt werden können. Dies ermöglicht Designs sowohl für Traktions- als auch für Boost-Anwendungen von Batteriespeichern. Diese Designs beinhalten eine galvanische Trennung und eine Stabilisierung des Zwischenkreises, die über die Steuerfähigkeit der eingesetzten Schalttopologien erreicht wird. Beides führt zusammen zu einen zu einer Vereinfachung der Leistungsverteilung und des Energiemanagements, und zum anderen zu der kostengünstigen Gestaltung von Leistungs-Verbrauchern und Traktionseinheiten. Außerdem können GaN-Transistoren gemeinsam in die Kühlung von passiven Bauelementen integriert werden, was zusätzlich den mechanischen Aufwand für eine Leistungselektronik verringert. Diese Rahmenbedingungen ermöglichen neuartige Gestaltungsmöglichkeiten von Energiespeichern und die Verteilung von elektrischer Leistung innerhalb eines Fahrzeuges. Der Vortrag wird eine Beispielsumsetzung für einen DC/DC-Wandler aufzeigen, der eine mit Niedervolt betriebene Batterie mit einem Hochvolt-Traktionskreis verbindet. Er wird aufzeigen, welchen Einfluss dies im genannten Beispiel auf die Gestaltung des Energiebordnetzes hat und wie sich das auf einen angeschlossenen elektrischen Antrieb auswirkt.
Author: Philip Dost
Co-author: Constantinos Sourkounis
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Despite the battery cells itself, the electronics, especially sensors make about 10 % of the system costs and volume in automotive applications. As the cell price and volume is decreasing, the amount of cells will increase within a Battery Electric Vehicle (BEV). Accordingly the number of monitored cells increases as there is often a 100 % monitoring rate in regard to li-ion battery systems (BS) due to safety reasons. This means that each cell is employed with a voltage sensor and each stack with a current sensor, or if a balancing system is employed, there might be an additional current sensor for each cell. With a stack as big as 12 cells, this means 13 or even 24 (if a balancing system is employed) sensors per stack. The number of sensors increases when taking temperature sensors into account. The newly developed sensor minimal battery observer allows decreasing this number of voltage and current sensors by 90 % down to two sensors per stack by keeping up the 100 % monitoring rate. This means that the presented system affords only two sensors to monitor 12 battery cells individually. This remarkable decrease of the number of sensors leads to a commensurate decrease of costs, weight and volume. Despite the reduction of sensors, it means a decrease of cables and assembling as well as construction costs. In addition to the sensor minimal observer system the system includes a cell balancing opportunity, which makes additional systems abdicable. This balancing system ensures an equivalent energy level in all associated cells to allow maximal energy output and extended service live. The service live can be extended to five times the service live of an unbalanced system for automotive application (end of life capacity 80 %). Concomitant the traction range is increased well after a few recharges due to the application of balancing systems.
Author: Michael Kiffmeier
Co-author: Prof. Dr.-Ing. Stephan Frei
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Das Kfz-Energiebordnetz ist heute aufgrund zunehmend voranschreitender Elektrifizierung und durch das Einbringen neuer Funktionen in bestehende Kfz-Architekturen deutlich komplexer als noch vor einigen Jahren. Diese Zunahme an Komplexität birgt das Risiko einer erhöhten Fehler- und somit Ausfallwahrscheinlichkeit. Kurzschlüsse, Leitungsbrüche, das unbeabsichtigte Öffnen von Steckkontakten und auch Wackelkontakte könnten häufiger auftreten. Speziell die Sensorik und Aktorik rund um das autonome Fahren führt zudem zu deutlich erhöhten Anforderungen an die Zuverlässigkeit des Gesamtsystems. Damit werden also auch kritische Veränderungen, wie z.B. Alterungserscheinungen, relevanter und müssen ebenfalls erkennbar werden. Der hier vorgestellte Beitrag beschäftigt sich damit, die Erfüllung der steigenden Sicherheitsanforderungen mit Hilfe neuer Monitoring- und Diagnosetechniken zu unterstützen. Zu Eigendiagnosezwecken ist bereits eine große Anzahl an Steuergeräten mit Sensorik zur Überwachung ihrer elektrischen Eigenschaften ausgestattet. Zusätzlich ist nahezu jedes Steuergerät an einen Kommunikationsbus angeschlossen, welcher es ermöglicht, solche Messwerte im Rahmen einer Messwertfusion in einem zentralen Steuergerät, z.B. dem Gateway, Batterie- oder Energiemanager, zu sammeln. Durch einen weitestgehend modellbasierten Entwicklungsprozess von Energiebordnetzen sind die Initialparameter und Modelle der relevanten Komponenten entweder bereits vorhanden oder können durch eine entsprechende Modellierung und Parameterbestimmung gewonnen werden. Fehler bedeuten eine Modellveränderung. Die Komponentenmodelle für die einwandfreie Funktion müssen durch Fehlermodelle ausgetauscht werden. Die möglichen Fehler führen zu einer Permutationsmatrix, welche zu jedem möglichen Gesamtbordnetzzustand einen Vektor mit Komponentenströmen und -spannungen erzeugen kann. Durch die Fusion der vorhandenen Sensordaten in einem zentralen Punkt können nun Fehlernormen zwischen dem Messvektor und den erzeugten Lösungsvektoren aus der Simulation erstellt werden. Die kleinste Abweichung kann als wahrscheinlichster Zustand aufgefasst werden. Bei einer Berücksichtigung von Fehlermodellen der Leitungen können auf diese Weise auch kritische Zustände erkannt werden. Somit ist eine Bewertung des Leitungsnetzes zur Energieverteilung auf Basis bereits heute vorhandener Messungen möglich. In diesem Beitrag wird die theoretische Ausarbeitung der Methode vorgestellt und Schlüsselstellen werden identifiziert und diskutiert. Anschließend wird anhand eines Laborbordnetzaufbaus die Wirksamkeit der Methode validiert.
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