Session 4: Battery Pack Engineering for Automotive Applications
Electrical management is crucial to ensure the reliability and safety of automotive batteries in the field. In this session, developers of battery-management electronics and pack integration hardware will discuss requirements, challenges, and solutions for a cost-effective integration of energy-storage packs into electrified vehicles.
Session Chairman: Bertrand Largy, Responsable service métiers du GMP électrique, Renault
After 6 years in the railway industry as test and project engineer, and 3 years experience in the space industry specialised in magnetic bearings as a project engineer, Bertrand Largy spent ten years in Renault's Electric Vehicle Development department. Today he is the manager of the Electrotechnic Engineering Department of the Vehicle Engineering Division, and is in charge of electric energy generation, storage and management.
SESSION AGENDA
Development of Battery Packs for Renault's Electric Vehicles Masato Origuchi, EV Battery Development Group Leader, Renault
Abstract
Three first Renault mass production electric vehicles equipped with Li-ion batteries have been already available in the market since several months and now the last one Zoe unveiled in the previous auto-show is under finalization toward its start of production in this summer.
Kangoo Z.E. - Electric light commercial van with basic EV features Fluence Z.E. - World first EV compatible with the battery Quick Drop system Twizy - New concept of two-seater commuter Zoe - Newly designed platform dedicated for EV
Each vehicle has its own unique feature in different platform with different battery packaging. This presentation will describe such different battery packs of these four vehicles especially with following topics:
Major specifications and features of each battery pack
Capacity and performances
Packaging and its structure
Unique features
Difference in the thermal management
Need or non-need of a cooling system
Different cooling systems for different features
Finally the presentation will also touch on the subject of the safety of the battery pack which might be one of the hottest topics of the moment.
Close Abstract
Modular Approaches Automotive Battery Solutions Christian Mohrdieck, Director of Fuel Cell & Battery Drive Development, Daimler AG
Abstract
To ensure sustainable individual mobility worldwide, despite the prospect of future limited crude oil resources, and to meet future regulations targets in Europe (ACEA CO2 Self-Commitment) alternative powertrains based on hybrid technology, fuel-cell technology and battery technology are neccassary.
There are three steps towards the “Energy for the Future” at Daimler: efficient cars based on improved internal combustion engines with or without hybridization, improved conventional and alternative fuels (e.g. biomass-to-liquid), and emissions-free vehicles with fuel-cell/battery drive. Additionally, improvements can be expected with respect to aerodynamics and (lightweight) body design. The focus of this presentation is an overview of modular approaches for battery solutions. Looking onto the electrification roadmap we have to distinguised between three classes of batteries:
High Power/Low Energy-Density (HEV-applications, 1-1,5 kWh)
Medium Power/Medium Energy-Density (PHEV-applications, 6-9 kWh)
Description High-Voltage Li-Ion Battery System and Requirements
HV-battery systems consist on the cell modules with the cell supervising circuits, the thermal management system, the battery management system and the electric parts like shunts, plugs, etc.
The development knowledge of battery systems and their integration into the vehicle needs high mechanical integration-, electric-, electronically- and electrochemical competence.
The E/E topology consists of the battery management system (BMS) with a low-voltage and a high voltage part, the high-voltage cell supervising circuit (CSC) and the CSC-buscommunication between CSC and cell-module with the temperature sensors.
The key performance parameters are 1. Safety, 2. Cost/Lifetime and 3. Performance
Modular Approach:
Basis of the module concepts are standardized cells (VDA-formats).
Prismatic cells are preferred for hybrid solutions due to the height of the cells
Pouch cells are preferred for EV/REX-vehicles due to the good energy densities
Modular approaches refer to three levels: cell module, E/E modules and the SW module.
The three module levels will be described
Design-to-Cost Aspects:
The volumes of cells and batteries have the strongest impact on cost reduction.
The second biggest influence on cost is to introduce a modular strategy for the different applications.
One further impact on cost is the given space and location in the vehicle for the battery. Fixed battery
locations in a standardized compartment are future targets for electrical driven cars.
Close Abstract
The Evolution of a Modular Approach for HV Battery Systems Kai Ludwig, Manager Functions & Calibration R&D Battery, BPC Electrification
Abstract
BMW Peugeot Citroën Electrification continues the consequent development of modular battery components designed for the next generation of hybrid electric, plug-in hybrid electric and electric vehicles started at BMW Group. Standardization is a well-established approach to reduce development and validation efforts as well as product costs in car industry. A modular design, applied to the HV battery and its sub-components, results in cost reductions during the whole life cycle of electrified vehicle applications. One of the most popular examples is the cell module, based on a certain standardization of cell geometries. However, also a modular battery management system – including electric, electronic hardware and software algorithms – offers potentials both for part cost reduction and for an efficient component development, integration and validation.
The presentation gives an overview of the modular design strategy of BMW Peugeot Citroën Electrification.
The basic concept of the next generation of battery packs will be explained
The modular approach for battery management systems will be introduced
Impacts on function development, validation, calibration and integration are addressed.
Summary:
Rollout of a cell module design with prismatic hard-case cell types based on VDA standard
Further cost down potentials based on modular sub-components achieved
Modular approach implemented within battery management electronics and function development
A common battery platform for several vehicle applications reduces development and validation efforts
BPC Electrification will be the center of competence for power-train electrification for BMW Group and PSA.
Close Abstract
PHEV Battery Packs – The Challenge to Combine EV and HEV Functionality Peter Pichler, Product Manager Battery Systems, Magna E-Car Systems
Abstract
The load requirements for battery packs for hybrids and electric vehicles and therefore also for the cells are very different. HEV applications request short but high load pulses (up to 50C) and only a very limited useable energy range of approx. 150Wh. Compared to that electric vehicles load the battery pack continuously with low power but utilizing the maximum energy range. As a result battery pack design for HEV and EV is very different. The challenge for designing a battery pack for a PHEV application is to combine the specific needs for HEV and EV driving mode in an optimal way.
This presentation will outline following items relating to PHEV Battery packs:
System architecture
Energy and power performance
Packaging
Battery management
Cooling
Cell technologies
Close Abstract
High-Reliability Pouch Cell, Module, and Pack Design Uwe Wiedemann, Product Manager, AVL List GmbH
Abstract
It doesn't matter if it is a PHEV or an EV: The battery is the key technology that decides upon economically attractive, save and reliable e-mobility. Batteries of the first generation that are currently on the market were developed to demonstrate a certain electric range with a save technology. The second generation of batteries that is developed right now needs to address multiple aspects like costs, reliability, durability, energy density and hence electric range, recyclability and other typical automotive requirements that had less emphasis during the first generation.
Regarding cells, price has meanwhile reached a very attractive level within a few years. An energy density target of 200 Wh/kg will be reached in the next generation of cells. Now it is crucial to reduce costs on the battery pack system side correspondingly. Every component shall be assessed and optimized: connectors, contactors, module electronics, battery control unit, housing, etc.
This presentation only focuses on two aspects: cooling system simulation and design as well as an innovative connection method for pouch type cells.
Targets for the cooling system:
Optimal cooling performance in accordance to the vehicle requirements
Minimal temperature gradient – is a ΔT of 2 K realistic and needed?
Minimum weight and high mechanical integration.
Results for the cooling system:
Contribution to overall battery pack weight
Pack temperature gradient
Chosen materials and & manufacturing cost
Simulation vs. Measurement results.
Requirements for innovative connection method for pouch cells:
High mechanical robustness
Less impact on cell than laser welding
Cheaper in manufacturing
Better electrical performance than existing methods
Results of connection solution:
Electrical measurement results
Thermal measurement results
Mechanical validation results
Tooling and manufacturing costs and advantages
Summary:
Advanced simulation techniques to optimize the thermal management system of batteries bear a high cost saving potential for battery systems.
Optimized cooling systems that are aligned with the vehicle control strategy can reduce the system weight significantly.
Innovative solutions have to be found to resolve existing challenges in the battery development area. The shown connection method as replacement for existing welding processes is one example.
Close Abstract
Battery Management Architecture and Algorithm for Automotive Application Kei Sakabe, Researcher, Hitachi Research Laboratory, Hitachi, Ltd.
Abstract
In response to typical issues concerning lithium-ion battery systems for automotive application, a battery management architecture and algorighm were devised. This presentation reveals the difference between a lead battery system and a lithium-ion battery system. It also mentions following novel hardware architecture and battery management algorighm which realizes customers’ evolving performance.
