Thermocouples and Sensor Healing

Printed arrays of temperature sensors for the Li-Ion battery market in second life. Self-healing effect as a further contribution to resource economy.

Increased need for retrofit to monitor temperature in Li-Ion-batteries with focus on second life applications

The intermittence of renewable power generation requires energy storage to provide stable power supply. There are several technologies to store energy. The currently most favored way to provide a reserve for grid stabilization is using Li-ion batteries. Continuous growth will likely trigger competition for resources to make new batteries. Thus, we believe that batteries that have been retired for their primary use in electric cars (SOH < 80%), are going to have a “second life” to be used as batteries in energy storage till they will be recycled to recover their valuable components to build new batteries.

Most batteries eligible for a second life had been built some years ago. Subsequent concerns are to enable monitoring of secure operations, most importantly temperature, as Li-Ion Batteries must not enflame due to their composition enabling severe, sometime catastrophic fires. As the large stationary storage might face substitution technologies, we believe that private residential use is the most interesting market segment as there are hardly alternatives and yet a lack of new Li-Ion batteries that this sector will face. Potentially, large stationary storage will also be built based using “second life batteries” and so we consider this market, too, yet with lesser focus. 

Further, once the technology has created reference cases in stationary energy storage to support grid stabilization we want to offer the technology to the e-car manufacturing industry.

A new technology to ensure more accurate temperature measuring

The quality of temperature sensor is describe by applicable temperature range, their resilience to humidity and the accuracy they provide within a defined set of environmental parameters. Currently, sensors that provide

  • An accuracy of +/- 1 K over a multi sensor array is not available on the market
  • Over a broad range of parameters stipulated by the battery operations

is not available. Thermistors are very unlikely to meet such requirements, as they are heavily dependent upon ambient temperatures. We have chosen thermocouples and we believe to achieve the required accuracy of +/- 1 K featuring larger multi sensor arrays.

Our temperature sensors also show approximately 2 times better sensor sensitivity when measuring temperature, translating into an improved cost efficiency.

Self-healing Sensor Technology to improve production yield

At the Helmholtz-Zentrum Dresden-Rossendorf we have developed a technology to create temperature sensors using printing techniques with previously unknown self-healing properties. As a result, we can heal sensors either in the aftermath of their mounting with potentially some sensors being abused. Obviously maintenance action will be much simplier.

So this capability will allow you to make all sensors effectively work, as potentially last step in you manufacturing process.

Helmholtz Innovation Laboratory - your partner

We estimate the global market for our innovative temperature sensors in the rechargeable battery segment alone to be around 20 million. € p.a. The application in e-cars will trigger som [    ] m€.

As part of the project we will provide functional paste, printed sensor elements and printed sensor arrays. Using this technology other types of sensors, including those for measuring other physical quantities (magnetic field or stress).

After the project is completed, we want to found a spin-off that will focus on the production and marketing of printed sensors for measuring temperature and printed, self-healing sensors for other measurements and applications. First we will focus on stationary energy storage and using this as a reference laveraging on e-car applications

Our Partners

In addition to our partners LioVolt GmbH, Beifuss Industrie Systeme GmbH and Freudenberg Siebdruck GmbH, we are looking for other companies as partners for this project.