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Bosch Fuel Cell Stacks: “This is How Series Production Will Succeed”

By May 24, 2020 6   min read  (1023 words)

May 24, 2020 |

What is the formula for success in the production of fuel cell stacks? Together with the start-up PowerCell Sweden, Bosch is now driving the breakthrough in mass production.

Why the mobile fuel cell has great potential

Achim Moritz (left), Product Manager Fuel Cell Mobility Solutions, Bosch, and Per Wassén, CEO PowerCell Sweden.

Refueling only takes a few minutes, then the range is over 500 kilometers – a car with a fuel cell hardly differs from a vehicle with a petrol or diesel engine. Except, of course, on one important point: thanks to the electric drive, there are no local emissions. This is why hydrogen technology plays an important role when it comes to achieving mobility that is as climate-friendly as possible, especially when it comes to electrifying heavy commercial vehicles. However, high production costs currently stand in the way of mass use such as in vehicles with internal combustion engines. Bosch wants to solve this problem together with the start-up PowerCell Sweden. The two companies have taken the heart of the hydrogen drive: the fuel cell stack.

The fuel cell stack is being developed for series production.

H₂ 

Hydrogen – the fuel. Hydrogen molecules are located in the fuel cell on the side of the anode. They consist of electrons and protons.


“By working with Bosch, we can quickly develop our technology to readiness for series production.” Per Wassén, CEO PowerCell Sweden


What is important in series production

Because a single fuel cell can only generate little energy, many of them are connected in a stack. A good 400 cells result in a total electrical output of up to 120 kW (163 hp). With higher power requirements in commercial vehicles, the number of stacks is increased accordingly. Achim Moritz does not want to reveal too much about how to manufacture the fuel cell and the stack more cheaply. “An important starting point is the use of cheaper materials,” says the Product Manager Fuel Cell Mobility Solutions. “In addition, we expect progress, for example in increasing the output from a single cell.” But already through series production and the associated higher According to Moritz, the cost of a single stack could be significantly reduced.

However, mass-producing a complex system such as a mobile fuel cell stack is demanding. “Every single stack has to work reliably,” says Moritz, and adds: “Control units therefore play a central role in vehicle operation.” The powerful mini-computers control all functions of the fuel cell and ultimately ensure the most efficient drive possible – exactly like the electronic engine control units on vehicles with petrol and diesel units. This is a great advantage for Bosch: The company can look back on a long history of developing control units. “We have a lot of expertise and experience in-house for this,” says Moritz.

This is what the fuel cell stacks look like

O₂ 

Atmospheric oxygen – the reaction partner. It is located on the side of the cathode in the fuel cell. O₂ and H₂, as well as the cathode and anode, are separated by a membrane. It is only permeable to the protons of the hydrogen molecules.

What happens in a fuel cell stack

An animation explains what exactly happens in a fuel cell.

Experience gives you a head start

Which challenges still have to be overcome for reliable series production? In order to understand this, it is worth taking a look at the technological details of the fuel cell: hydrogen has a small molecular size and low viscosity, making it very thin – the stack must, therefore, be perfectly sealed for efficient and safe operation. “The sealing length of a 120 kW stack is around one kilometer. Here we work to meet the high quality standards for automotive applications,” says Moritz. With other drive types, Bosch has already proven that its experts have extensive experience and expertise in parallel product and process development – so-called simultaneous engineering. This includes

“The parallel development of product and manufacturing process is our strength,” says Moritz. Per Wassén is also convinced of this. “Bosch is the leading supplier for automotive technology and has enormous experience and innovative strength here,” says the CEO of PowerCell Sweden. “This industry is characterized by large, international companies, and there are long lead times and very high requirements. A start-up like PowerCell – however technologically advanced it might be – alone would have a hard time tapping into the huge market potential. By working with Bosch, we can help our technology breakthrough much faster. ”

2H₂ + O₂ → 2H₂O

Water – the waste product. It occurs when the hydrogen protons in the fuel cell react with the oxygen.

Kilos are refueled instead of liters

As a rule of thumb for the energy content, one kilo of hydrogen enables a range of around 100 kilometers for cars. A heavy truck requires around ten kilos for the same distance.

DC

Direct current – the desired product. It consists of the hydrogen electrons that flow from the anode to the cathode via the consumer located outside the fuel cell.
It is converted into alternating current by an inverter, which then drives the electric motor.

While companies like Bosch and PowerCell are pushing the serial production of the mobile fuel cell, another hurdle for the spread of the technology is being tackled: In many countries the number of hydrogen filling stations is already growing. The expansion of the infrastructure is funded by the state in many places and also promoted by associations such as the Hydrogen Council. “We are concentrating on the markets of China, North America and Europe, where we see increasing economic support for the fuel cell electric drive,” says Achim Moritz.

This support stems from the knowledge that the path to zero-emission mobility must be open to technology. Just as gasoline and diesel are continuously being improved on the combustion side, so is the situation with electromobility with the simultaneous development of the purely battery-electric drive and the fuel cell drive. Bosch has already internalized this open attitude. The result: the innovative fuel cell stacks are to come off the assembly line at the Bosch plant in Bamberg from 2022.


“We see series production as an opportunity to significantly reduce costs with larger quantities.”

Achim Moritz, Product Manager Fuel Cell Mobility Solutions, Bosch


Source: BOSCH

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