Interview with Jens Obernolte “Reducing the loss of range intelligently”

Mr Obernolte, the energy consumption of the ID.3 and ID.4 models increases significantly in winter – particularly when customers make a lot of short journeys. Why is that?

That is an effect that applies to every all-electric car. They use electricity from the traction battery to bring the air in the interior of the car, and any battery cells below a certain temperature, up to the right temperature – this increases consumption and reduces range. This is completely different to a model with a combustion engine, which uses the waste heat from the engine, of which there is plenty, to heat with virtually no losses.

Why does the battery in an electric car need to be kept at a certain temperature?

Because the cells only work at their best in a defined temperature range – this applies to the power output, as well as to recuperation and rapid charging with direct current. And in terms of thermal management, our goal has been to run the battery as sparingly as possible, so that it only ages slowly. It has its own fluid circuit, which keeps it at the right temperature. Depending on the battery’s temperature, in winter we use a powerful auxiliary heater to warm up the coolant until the cells are all at the ideal operating temperature.

And if customers only ever make short journeys …

… the battery always cools down in between journeys, meaning that it always needs to be heated again the next time it is used. However, I would like to point out here that we have already significantly reduced the energy required to heat the battery over a large temperature range. The cars we have delivered since early summer 2021 come with this improvement as standard; we adapted the software to make this possible. Customer cars will soon receive this improvement as an update – which shows how successful and effective our software strategy is.

And what about heating the interior?

That also uses a high-voltage heater as standard, with the option of adding a heat pump. The heat pump reduces energy consumption, particularly in stop-and-go traffic and in outside temperatures below zero degrees Celsius.

Customers can activate the interior heating before starting their car. Where does the power come from – the car battery or the public grid?

The preheating of the interior can be operated off-grid and on-grid, regardless of the configuration. Off-grid, meaning without being connected to the grid, it is the car’s own battery that supplies the energy required, which reduces the range. On-grid, the electricity comes from the public grid …

… which is beneficial to the range of the car.

That’s right – it is in most customers’ interest to use on-grid preheating. This is why, in our new ID. models, the battery is also brought to the required temperature using on-grid electricity when the customer activates preheating. This is an improvement that comes with the new ID. Software 3.0, which is now incorporated into production. Using energy from the public grid significantly increases range in cold weather.

Is there a configuration you would recommend for ID. customers – such as a specific combination of engine and battery?

No, there is hardly any difference between the individual variants when it comes to efficiency. The features such as the dual-zone or 3-zone “Climatronic” climate control are much more important – the benefit of this is that you can restrict the heating to the driver’s side if it is just you in the car. Heated seats and steering wheel heating are another option. They create warm contact surfaces, which allows you to turn down the heating a little bit.

And what should customers bear in mind on everyday journeys?

In urban areas, you should switch to level B, in order to recuperate as much energy as possible with the higher regeneration performance. If you drive sensibly, you can almost get through the city without having to brake at all. In the countryside and on motorways, you should select level D. With this mode, the low driving resistance of the ID. models means they are able to sail for long periods, during which they only use their kinetic energy.

How do the efficiency systems contribute to saving energy?

All ID. models have an intelligent system on board as standard – the Eco Assistant, which evaluates navigation data and road signs. When the car is approaching a zone requiring a lower speed – such as a village, roundabout, or a corner – the system shows the driver that they need to take their foot off the accelerator. And, where possible, the Eco Assistant also increases the recuperation automatically. The aim is to increase energy efficiency through thinking ahead while driving.

What other tips do you have?

Eco mode in the driving profile selection also has potential for savings. This reduces the power of the interior air conditioning slightly. Most customers are aware of the benefits of keeping windows closed to achieve better aerodynamics and, obviously, not carrying any unnecessary weight in the car, but it is worth mentioning this again anyway.

Having said all that, these driving and equipment tips cannot offset the basic loss of range in winter, can they?

They can significantly reduce the loss, without comprimising on comfort. However, loss of range with an electric car cannot be avoided entirely. The winter tyres alone, with their high roll resistance, increase consumption. And the air density is also a factor – it is higher in cold weather, which in turn affects the aerodynamic drag. However, having said all that, we must not forget that most customers travel less than 50 kilometres a day in their car – they don’t really need to worry too much about the range. In the case of customers who drive longer distances, the effort of heating the battery and interior have much less effect on the range.