Making a connection: An innovative new joining method to boost EV battery performance – 23/12/2020

DZP Technologies is a prime example of the new wave of companies bringing innovative ideas into the automotive industry. A specialist in electronic materials, its main expertise lies in conductive inks and pastes for applications such as IoT and wearables. 

Having previously developed conductive adhesives for power electronics, the company’s engineers were keen to explore other potential applications within the electric vehicle sector. Through the Advanced Propulsion Centre’s Technology Developer Accelerator Programme (TDAP), they were introduced to E4tech, who helped them to identify several potential markets and take the decision to focus on a method for connecting the cells within a lithium ion battery pack. This is typically done with techniques such as welding or wire bonding, but there was evidence to suggest that DZP’s conductive materials could provide a better solution.  

“The main issue is that lithium ion batteries are flammable and potentially explosive,.Joining them with conventional techniques is inherently tricky as a result,” comments Dr Zlatka Stoeva, Managing Director of DZP Technologies.  

The company successfully applied to the APC for the third wave of TDAP, securing over £100,000 of grant funding. 

During TDAP DZP were able to explore the use of their technology to a wide variety of applications and opportunities. Having selected battery joining as the lead candidate, they set about comparing their technology to competing joining methods. Several significant selling points were identified. Notably, it was compatible with a wide range of materials. Similarly, the thermal and mechanical stresses subjected to the part were extremely low, minimising its impact. They also found a significant further benefit; their technology allows the cells to be disassembled relatively easily for repair, recycling or second-life applications. 

In the long term, there is real value in DZP’s technology with its ability to enable new concepts in battery design. Dr Stoeva points to the example of cell-to-chassis batteries pioneered by Chinese firm CATL. These eliminate the traditional battery casing and mount the cells directly to the structure of the vehicle, with reportedly huge gains in energy density and vehicle range.  

“The cell-to-chassis concept would be almost impossible with laser welding. Our technology can be a gamechanger, because it enables new battery designs like that,” notes Stoeva. “Testing has also shown that the current-carrying capacity of our technology is much higher than wire bonding, which could enable the use of larger, high-current cells.” 

 

As part of the project, DZP produced a working six-cell prototype pack. This was used to carry out electrical characterisation in-house and at the National Physical Laboratory. Experts from the APC were also able to provide guidance on business planning and market research. 

“TDAP has helped us to identify a new business opportunity that we probably wouldn’t have spotted otherwise,” comments Stoeva. “It accelerated the technical development and gave us a lot of new contacts in the market. It helped us to understand the automotive sector, and especially today’s trend towards electrification. Perhaps most importantly, it gave us the confidence that the automotive sector was within reach for an SME such as ourselves.” 

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