The battery: the heart of an electric vehicle

Dr. Joachim Döhner, Vice President Business Unit Battery, KUKA Division Automotive


Battery technology will play a major role in product development across all sectors of the automotive industry with the continual drive to reduce vehicle emissions. Especially in the field of e-mobility, the demand for energy storage is of paramount importance. We are aware of these challenges and develop intelligent concepts for the highly complex production of battery modules and battery packs for the automotive industry.

In order to be able to develop innovative and efficient automation concepts, it is of great importance for us to know the end product down to the smallest detail. For example, material properties, specifications of technical components or special properties of the end product are important information. As a reliable partner for the development of technically sophisticated production concepts for battery modules and packs, we are familiar with the most diverse battery concepts down to the smallest detail.

We asked our KUKA Vice President of the Battery business unit, Dr. Joachim Döhner, five questions about batteries in electric and hybrid vehicles.

1. What is special about batteries used in electric and hybrid cars?

Unlike batteries from low-power and low-capacity, that we are using in our leisure time to run for example a kitchen scale or a flashlight, electric and hybrid electric vehicles require high-performance batteries, satisfying special requirements concerning power, capacity, weight, size and reliability. To deliver the desired voltage, capacity, or energy and power density an assembly of a large number of preferably identical batteries or individual battery cells is necessary: a battery pack.

2. So far so good. Now it comes to the complex part: What is a battery made up of?

Batteries are made up of various components. This includes cells, which are connected in serial or parallel strings to achieve the desired voltage and capacity. In addition to cells, batteries also com-prise a cooling system, a Battery Management System (BMS), busbars, cabling, shunts, wiring har-nesses, sensors for supervision of battery parameters as well as a robust & media tight housing.

Busbars connect the cells electrically while wiring harnesses connect temperature and voltage sensors from the cells to the Battery Management System (BMS), which controls the battery.
The traction cable is a high voltage and high current cable that connects the cell modules together and carries the main power round the battery. To connect the battery with the vehicle a vehicle interface is needed that transfers information by CAN-BUS – an automotive standard protocol. This protocol gives us information about the state of charge, the battery voltage, temperature and the battery amperage and thus power supply or consumption. To measure the amount of amps during the process of discharge and charge a measuring device must also be included. To reduce the risk of receiving a shock from the battery the isolation monitoring device checks continuously if there is an electrical leakage to ground. Last but not least every battery needs a main switch, which candisrupt both positive and negative connections, thereby rendering the battery safe. This component is called main contactor relay.

3. What´s the heart of a battery?

Definitely the cells! They are the building blocks of batteries. A cell is a closed power source, in which energy is stored chemically. This energy is stored respectively released due to internal electro-chemical reactions as a flow of electrons through an external circuit. In electric vehicles, usually Lithium-ion-cells are used. Lithium-ion cells have considerably greater energy density than previously-used chemistries. This makes them particularly suitable for automotive applications. They are also considered safer, less toxic, and offer better energy efficiency with significantly longer cycle life.

5. And what is KUKA doing to support the automotive industry on their way to the “green” energy?

We support our customers with intelligent automation solutions for battery production. We provide full service along the complete value chain and help our customers to find the best solution for their specific needs – from individual robots to complete turn-key production lines.

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