Integration of Alternative Propulsion Systems – Challenges and Solutions for Vehicle Manufacturers

RANGE AND CHARGING ARE (STILL) CENTRAL ISSUES OF ALTERNATIVE PROPULSION SYSTEMS

Just as in the first electrification period 120 years ago, maximum reach and charging duration are still the key issues of the second electrification period today. Customers are now used to driving ranges of 700 kilometers or more, only interrupted by a fuel stop of just a few minutes. Many BEV drivers find it simply unacceptable that to drive only 300 kilometers, BEVs require 30 minutes of waiting time for a full charge. They subsequently charge their vehicles “on-the-go,” whenever the opportunity emerges. A BEV manufacturer able to increase maximum driving ranges while significantly lowering charging durations will have an edge in the competition for global market shares and think about alternative propulsion systems.

The EV battery and its charging behavior are key to solve these two issues. As the race for the most competitive battery cell system is still open, there remains a lot of research and development (R&D) and subsequent testing to do. Both new and existing battery technologies require extensive testing and validation efforts, so automotive manufacturers eager to stay on top of the technological race should consider cooperating with a strong automotive manufacturing partner who owns separate battery testing grounds. This will result in significantly shorter development times and market entry. Modern lithium-ion batteries with liquid electrolytes can be further developed into other systems (e.g., solid-state batteries), promising higher energy density, reduced installation space and weight, and constant maximum range.

Alternative propulsion systems - charging strategies for electric batteries need to be developed

Aside from size and energy density, electric batteries also require a suitable charging strategy. Such a proper charging strategy is a key element of a successful overall operating strategy - for one key reason: The actual charging time of a battery strongly depends on whether and how the battery can handle constantly high charging power. BEV owners may be disappointed if the promised power peaks are only met for around 20 to 30% of the total charging duration and are then halved or even reduced to 33% power because the battery cannot handle them. This can increase both charging times and user frustration and hurt the image of both the manufacturer and BEV technology in general.

If charging voltages are to remain on a constantly high level throughout the entire charging process, manufacturers need an intelligent battery charging strategy coupled with a sophisticated thermal management system. The key lies in implementing appropriate counter measures to prevent overheating in the first place, through quick heating at the start or specific cooling measures during the charging process, for example. This way, the charging time can be reduced.

Intelligent operational strategies by optimized electric battery charging

Optimized charging strategies also allow manufacturers to implement a successful operational strategy. Such a strategy can assist drivers in choosing the ideal time to charge the battery. For example, the EV’s infotainment system could recommend the driver to immediately charge the vehicle after driving instead of charging it before the next drive. As the battery would still be heated from the use period, this method would save battery performance while optimizing charging currents, particularly during colder seasons. A complementary operational strategy could be implemented to reduce cooling time during the summer.

Additionally, the driver could be reminded to use the navigation system even on recurring, familiar routes to determine the next ideal time to charge as well as activate the thermal management system to initiate heating/cooling processes before arriving at the charging station.

LOW ENERGY CONSUMPTION VIA LOWERING RESISTANCES

There is also ample potential to reduce energy consumption while driving. Efficiency can be increased by lowering driving resistances, like an aerodynamic car body to reduce air resistance, the most important metric at speeds of 70km/h or higher. Further potential lies in rolling resistance, which is not only influenced by tires supplied by the tire manufacturer, but also significantly by frictional resistance in the entire powertrain chain: electric motor, reduction gears, differentials, wheel bearings - all of these must be considered in the development of the BEV so as not to waste precious battery power.

A competent automotive manufacturing partner of alternative propulsion systems will not only provide the completely electrified powertrain including electronic control, but should also possess the capabilities and infrastructure to test and validate their propulsion system for all road and load scenarios and evaluate the mechanical properties and energy currents under various conditions.

Smart thermal management is important

Electric and electronic components (E/E components) need to be trimmed for minimal power usage and maximum efficiency. The inverter, a device that converts the direct current (DC) from the battery into alternating current (AC), plays a major role in ensuring said efficiency.

To build an energy-efficient vehicle, its interior thermal management (how the interior is heated and/or cooled) plays an important role.

With ICE’s, the heat generated by the engine is used as a free source of heat for the interior. An EV’s powertrain on the other hand hardly produces excess heat and this is key for the exceptional efficiency of BEVs, it is not enough to keep passengers warm. And while it is fairly simple to implement electrical interior heating on a technical basis, its energy consumption will reduce an EV’s maximum driving range, especially during cold seasons.

The electric thermal pump is an efficient solution for this dilemma. It uses the residual heat from outside the car to increase temperatures inside the car. If a BEV employs smart thermal management and prepares its interior before departure, the power consumption for heating can be lowered significantly, leading to a longer range in the cold seasons. The more sophisticated a BEV’s operational strategy is, and the more efforts are placed on its thermal management, the more reliable it is in sustaining its maximum range.

SUPPLY CHAINS FOR BEVs MUST BE WELL-ORGANIZED

Cooling the vehicle interior during warm seasons is also part of every thermal management concept. In BEVs, this is handled by an electric A/C compressor. Although A/C has a lower energy demand than heating, a well-controlled A/C compressor and A/C system with optimized thermal management go a long way to reduce total energy consumption of a BEV. Still, the A/C system needs to be powerful enough to prevent fogged window panes even under difficult conditions.

Even the best manufacturing partners and suppliers are useless if supply chains are insufficiently organized. With the semi-conductor crisis, Covid, and the war in Ukraine, it is clearer than ever that supply and production chains need to be agile and flexible to withstand rapid regional and global changes. Employing numerous regional sub suppliers for base components is vital for ensuring secure supply chains and softening the impact of supply shortages. This way, a considerate development and production partner can keep the supply of vehicle components as well as complete vehicles running.

VEHICLE MANUFACTURING PARTNERS MUST BE FAMILIAR WITH MARKET CONDITIONS AND REGULATIONS

The complete vehicle development of a BEV in particular requires a lot of preparatory planning by the manufacturing partner. The future effects on materials, global laws and homologation regulations, production, and distribution must be considered starting in the concept phase. Only if manufacturers are aware of the different conditions each market operates under will they be able to prevent later mistakes – and the costs of fixing them.

Aside from cost transparency and cost supervision, end customer’s satisfaction plays an important role. End customers will only develop brand loyalty if they are satisfied with their purchase. Providing a positive complete package for new customers is imperative, especially as they shift from ICEs to BEVs. Ultimately, the total user experience should leave BEV drivers more satisfied than with their old ICE. The EV should be more pleasant to use and drive than an ICE – and features like seamless (and soundless) acceleration out of a standstill are important for a vehicle, but not enough advantages for everyday use.