The needs within the rapidly increasing electrification of the global vehicle fleet place new demands on both materials and surfaces. In a new project, the goal is to develop an electrolytic process for corrosion protection of battery terminals and contacts.
The electrical losses in an electric car’s drive system are typically 20%. If these could be eliminated, the range would be extended or the batteries could be made smaller and give the car maintained performance at a lower cost. A battery pack consists of many individual battery cells. The electrical losses in all the contact points needed are significant. Today, aluminum contacts are used. These are protected by a paste that, among other things, prevents the aluminum from oxidizing.
The problems with contact surfaces are a sequence of events that together contribute to deteriorating properties. Heat from the batteries and the heat that arises in the contact surfaces create movements. This can contribute to altered properties of the surfaces such as brittleness, oxidation or other types of corrosion processes. This results in poorer electrical contact, which in turn increases heat generation. And so the negative spiral continues. There are various solutions to the problem, such as gilding contact surfaces, but the costs for this are too high for the automotive industry.
– There are also other alternatives, but there is no solution today associated with acceptable costs, says Anders Skalsky, CEO of Provexa Technology.
Anders Skalsky, Provexa Technology. Photo: Ytforum
A Meteor can solve the problem
Provexa Technology was recently granted a research grant from Vinnova, a Swedish government agency for research funding, to develop an electrolytic process for corrosion protection of battery terminals and contacts. A two-year project is initiated under the name Meteor to develop a method for depositing a coating that meets the requirement specifications for the application. The electrical conductivity of the coating and any corrosion products must be satisfactory. Low thermal expansion reduces the movements in the contact during temperature changes.
Invar is an alloy between iron and nickel with a coefficient of thermal expansion close to zero. Therefore, Provexa has chosen to invest in that material as a starting point for the project. The ambition is to develop a process which, in addition to low thermal expansion, has good corrosion properties and high ductility. In addition, the costs must be reasonable.
– We have made initial attempts that indicate good opportunities to develop a process that provides a coating with the required properties. Of course, plenty of work remains, says Skalsky.
Today’s standardized test methods are not enough to be able to show that a coating really has the desired properties. In collaboration with its customers, Provexa Technology has supplemented its equipment for corrosion tests. Tests can now be performed with applied voltage to the test objects in order to mimic the environment in an electric car. A wider temperature range can also be used, from −40 ° C to 140 ° C. If Meteor meets the desired requirement specifications, the method is expected to be widely used. Provexa’s hope is that it can be used by both contract surface treaters and companies that surface treat their own products.
More surface treatment in an electric car
Provexa’s assessment is that the value of surface treatment in an electric car is greater than for a traditional car with an internal combustion engine. There are, for example, fasteners in an electric car that in many cases need a different surface treatment than what is used today.
– We believe that the development in electrification of vehicles will explode and we want to be a part of that journey, Skalsky emphasizes.
An indication of the forces driving this process is the testing grounds that is now being built by Chalmers and Rise. An investment of 1.3 billion SEK has been decided, which aims to make Sweden a world leader in electromobility.
– Over the next ten years, we can expect a sharp change in the surface treatment market, which will mean a great opportunity for companies that believe in the future and are willing to invest, says Anders Hultmark, CEO of Provexa Ytbehandling.
Provexa Technology – a growth company
After the three years that Provexa Technology has been operating, sales have increased. 2020 it reached close to seven million SEK. The stated ambition is an annual growth of 20 – 30%. Today, the company has agreements with 20 OEM companies. It is not just a focus on surface treatment, but all surface technical issues are included in the company’s business area. Sometimes, the best solution may be to change the base material instead of finding the right surface treatment. The laboratory in Gothenburg, Sweden has equipment for evaluating surfaces. There are also opportunities for test coatings on a lab and pilot scale. When a process is to be transferred into big-scale production, the proximity to the sister company Provexa Ytbehandling makes things easier.
– Today, we have developed methods such as Earth and Pluto and we have further processes underway. After three years of building up the business, we are well equipped to be an important partner in the rapid and large development that electrification will bring, says Anders Skalsky with confidence.
Read the article in the magazine Ytforum on the link (Swedish):
https://issuu.com/ytforum/docs/ytforum_2103_web/37
Text and image: Ytforum