- Focus on sustainability: Green transformation of waterborne paint formulations using bio-b...
- Coil coatings: PVDF versus SMP coil coating systems
- Focus on inks: Navigating beyond PTFE inks
- Choosing paint: The difference between Baby Boomers and Generations X, Y and Z
- Focus on fillers: Made in Germany
Sarah Gibbons reports on how the growth in electric car sales is prompting innovation within the automotive adhesives sector
While traditional benefits delivered by adhesives in the automotive industry – lightweighting and the ability to bond diverse substrates – remain a constant, the relentless evolution of the battery electric vehicle (BEV), is driving innovation in the segment, manufacturers and market analysts agree.
Automotive adhesives are widely used to improve versatility and strength, prevent corrosion associated with fastenings and reduce the overall weight of a vehicle, enhancing fuel efficiency and its associated carbon footprint.
In EVs, they help deliver thermal conductivity, keeping batteries at a safe temperature, helping boost their efficiency. As “the longest possible range is seen as the key to customer acceptance of electric cars,” noted adhesive manufacturer Coroplast Tape , based in Wuppertal, Germany, much R&D is devoted to improving battery power and safety, with adhesives and sealants a key focus.
The adhesives industry has enough heft to develop such products. According to the New York-based International Market Analysis Research and Consulting Group (IMARC Group), the global automotive adhesives market size reached US$5.9bn in 2022. IMARC expects the market to generate US$8bn in sales by 2028, at a compound annual growth rate (CAGR) of 5% during 2023-2028.
Structural adhesives and sealants for EV batteries is the key growth area – with sales expected to expand fivefold, from US$54.2M in 2021 to US$256.4M in 2030 at a CAGR of 18.85%
“The increasing adoption of EVs… is favouring the market growth,” it said in a 2023 report . “Moreover, various product innovation, such as the formulation of biodegradable automotive adhesives, are providing an impetus to the market growth,” as their use increases in vehicle interiors. Said the report: “The implementation of several government initiatives to reduce the environmental footprint of vehicles, is anticipated to drive the market growth further.”
Powering the growth
Structural adhesives and sealants for EV batteries is the key growth area – with sales expected to expand fivefold, from US$54.2M in 2021 to US$256.4M in 2030 at a CAGR of 18.85%, according to Straits Research, based in Maharashtra, India .
Coroplast said the fact manufacturers are achieving the energy density required for extra range by “packing more and more battery cells into the same amount of space” increases the impact risk of short circuits in individual battery cells – if an unprotected cell ignites, the entire battery overheats, with sparks spreading to neighbouring cells: “A chain reaction – also called thermal propagation – occurs. This can lead to a fire that is difficult to extinguish – or even to an explosion,” said a company note.
High-temperature resistant adhesive solutions with silicone foams and UV acrylate adhesives can prevent such reactions, increasing battery safety by enclosing individual battery cells, providing effective thermal insulation and protecting adjacent components.
The Ohio, USA-based adhesive dispensing solutions provider, the Nordson Corporation, has developed precision technology to help prevent thermal runaways. Interface materials, fixed with adhesives, in and around the battery pack, absorb heat from batteries, with adhesives applied by the company’s 797PCP-2K progressive cavity pumps in the appropriate cavities, to ensure a uniform bond, said an April (2023) company blog .
Casting, bonding and sealing specialists Wevo-Chemie, based in Ostfildern-Kemnat, Germany, has developed a liquid adhesive system specifically designed for EV batteries. Also equipped with optimised heat dissipation qualities, “these customisable polyurethanes allow for new possibilities in the design process,” said a company note.
Acceptance and use cases for autonomous vehicles differ greatly among major automotive markets – Global car user survey by Asahi Kasei
iTS system offers surface wetting and can also be used as structural adhesives that dissipate heat generated from battery cells to a heat sink.
Adhesives producer Henkel, based in Düsseldorf, Germany, has unveiled what it describes as “a first-of-its-kind injectable thermally conductive adhesive”, which it claims has been adopted by one of the world’s largest EV battery manufacturers (whose name it has thus far withheld. The new adhesive – Loctite TLB 9300 APSi – provides both structural bonding, as well as thermal conductivity).
Bonding battery cells to modules, or bonding cells directly to cooling systems, Loctite TLB 9300 APSi is a two-component polyurethane thermally conductive adhesive with a high thermal conductivity of 3W/mK, said the company.
A note said: “In addition to its heat management properties, it delivers a unique combination of good electrical insulation with high bonding performance to a variety of substrates. As a solvent-free solution that cures at room temperature without the need for additional energy consumption, it helps customers advance their sustainability agenda by reducing emissions and resource use, while also ensuring safer working environments.”
Stephan Hoefer, Global Market Strategy Head for e-mobility at Henkel, said in May (2023): “Thermal management in EV batteries is still one of the biggest challenges for electrified mobility. New designs targeting higher energy densities in battery packs bring along the requirement for multifunctional thermally conductive adhesives instead of classical thermal gap fillers.” 
Diversified manufacturer 3M, based in Minnesota, USA, has also launched new adhesive products to further battery development. Its 3M Sealant SZ1000 for EV Enclosure Sealing is a two-part, cure-in-place, flame retardant, foam, sealing solution. “What’s more, it offers a resealable seal that can be opened and closed allowing for battery servicing and ease of end-of-life recycling,” a spokesman told PPCJ.
3M UVi Semi-Structural Insulation Tape 1924B-1 provides insulation of metal surfaces in the EV battery pack assembly: “Most adhesive electrical insulation films use pressure sensitive adhesives, which limit their bond strength to metal surfaces,” said the spokesman.
“This product offers semi-structural overlap shear performance combined with a fast and easy UV initiation process application for increased battery pack manufacturing productivity,” said the spokesman.
Continuing the environmental theme, adhesives manufacturer DuPont, headquartered in Delaware, USA, has this year (2023) won an excellence award for their new adhesive product used to replace windshields.
BETASEA APEX involves primerless technology to eliminate the use of organic solvent-containing primers, reducing processing complexity and VOC (volatile organic compounds) emissions.
“DuPont’s internal calculations show that over 25,000 litres of solvent are no longer emitted into the atmosphere in North America alone by using BETASEAL APEX,” said a company note .
Despite this North American and European innovation, Asia Pacific automotive adhesives are still a key factor in promoting industry sales. Research published last year (2022) by India-based Allied Market Research  said the major trends boosting auto adhesive sales are “the increasing focus of automotive manufacturers on technological advancements and implementation of automotive fuel economy in various countries.”
It added that the polyamide segment dominates the global automotive adhesives market due to the ability to “easily form bonds with different materials”. The report added: “It is more flexible when compared to other hot melt systems and provides a wide range of thermal stability. It has excellent chemical resistance.”
2 – https://www.imarcgroup.com/automotive-adhesives-market#:~:text=The%20global%20automotive%20adhesives%20market%20size%20reached%20US%24,to%20bind%20composites%2C%20metals%2C%20plastic%20and%20materials%20together