By Landen MacDonald, Chemical Engineer Intern
Why are thermally conductive adhesive used in electric vehicles?
Thermally conductive adhesives play a crucial role in electric vehicle (EV) battery packs by addressing the critical need for efficient heat management. EV battery packs generate significant heat during operation, which can negatively impact their performance, lifespan, and safety. Thermally conductive adhesives help mitigate these issues by providing a reliable bond between battery cells and heat dissipation components, such as heat sinks or other thermal interface materials. These adhesives facilitate the transfer of heat away from the cells, allowing for effective dissipation and maintaining optimal operating temperatures. By ensuring proper thermal management, thermally conductive adhesives enhance the overall performance, reliability, and longevity of EV battery packs, contributing to improved efficiency, extended battery life, and enhanced safety during operation.
In addition to thermal management, thermally conductive adhesives contribute to the structural integrity of battery packs. They enable secure bonding between battery cells, preventing cell movement or misalignment, which can lead to mechanical stress and potential damage. By maintaining a stable and rigid battery pack configuration, these adhesives ensure the structural integrity of the battery pack, enhancing its overall reliability and safety. This becomes particularly crucial in applications subject to vibrations, shocks, or other mechanical stresses.
In use thermally conductive adhesives significantly contribute to the design of Cell-to-Pack batter pack configuration, where individual battery cells are directly bonded together. This configuration is gaining popularity due to its advantages in terms of cost, weight, and space savings. Thermally conductive adhesives play a pivotal role in Cell-to-Pack designs by promoting efficient heat transfer between the cells and providing structural integrity. Furthermore, the use of thermally conductive adhesives in Cell-to-Pack configurations streamlines the manufacturing process, reduces assembly complexity, and enables compact and lightweight battery pack designs.
What should you consider when selecting a thermally conductive adhesive?
When selecting the best thermally conductive adhesive for a specific application, a deep understanding of the thermal performance, structural characteristics, and processibility of the adhesives is needed. Thermally conductive adhesives are essential in battery pack applications, offering significant benefits in terms of thermal management, structural integrity, processability, and cell-to-pack configurations. These adhesives efficiently dissipate heat from battery cells, preventing overheating and ensuring optimal performance. They provide strong bonding and enhance structural integrity, reducing the risk of mechanical stress and component damage. In cell-to-pack configurations, thermally conductive adhesives enable uniform heat distribution and contribute to compact, lightweight designs. Moreover, their excellent processability simplifies assembly, streamlines manufacturing, and enhances overall productivity in battery pack production.
The following table lists six of the top thermally conductive adhesives used in battery packs. All the data is sourced directly from safety data sheets and is not independently verified by C-Therm. This list is not all inclusive and is not ranking the adhesives as they are listed in alphabetical order.
Top thermally conductive adhesives
| Company | Product | Thermal Conductivity | Density | Shear Strength | Base | Curing | Other Features |
|---|---|---|---|---|---|---|---|
| Coolmag [1] | Coolmag 29 LV | 1.8 W/(m*K) | 1.85 g/cc | No data available | Silicone | 24hr at 25 °C, 30min at 120 °C | Low stress, strong electrical insulation, NASA outgassing certification |
| HB Fuller [2] | EV Therm 440 | >1.0 W/(m*K) | 1.67 g/cc | 15 MPA | Modified acrylic | 24hr at 23 °C | 100% Reactive, excellent adhesion, easy pneumatic dispensing. |
| Henkel [3] | BERGQUIST® TLB SA2000 | 2.0 W/(m*K) | 2.4 g/cc | 1.4 MPa | Silicone Liquid | 10min at 150 °C | Extreme Temperature stability, one part formulation. |
| MG Chemicals [4] | 8329 TFF | 0.8 W/(m*K) | 1.6 g/ml | 8.3 N/mm2 | Epoxy | 4hr at 23 °C | Fast curing, strong electrical insulation, strong resistance to humidity. |
| Parker LORD [5] | CoolTherm® MT-322 | 1.7 W/(m*K) | 2.8 SG | 2.1 MPa | Silicone | 30min at 150 °C | Low stress, Durable, broad temperature range. |
| Wacker [6] | ELASTOSIL® TC 9800 CN | 0.85 W/(m*K) | 1.6g/cm^3 | No data Available | Silicone Rubber | 24hr at 23 °C | Natural-curing system, primeless adhesion. |
| 3M [7] | TC-2810 | 0.8-1.4 W/(m*K) | No data available | 18.62 N/mm2 | Epoxy | 24hr at 23 °C | Boron Nitride Filler, High adhesion, thin bonding line. |
Thermal conductivity measurements of the adhesives can be validated using the test methods available on C-Therm’s Trident™ Thermal Conductivity Instrument. More information regarding Trident™ can be found at the following link “Trident™ Thermal Conductive Instrument“, or you can contact us directly at sales@ctherm.com to learn more.
Figure 3: Trident™ Thermal Conductive Instrument
WORK CITED
[1] “Technical datasheet: CoolMagTM 29 LV,” Coolmag, https://coolmag.net/download/technical-datasheet-coolmag-29-lv/ (accessed Jul. 5, 2023).
[2] Ev therm 440 & EV Therm 440GB – H.B. Fuller, https://www.hbfuller.com/-/media/files/resource-library/tds/structural-marine-bonding/ev-battery/hb-fuller-ev-therm-440-tdsen.pdf (accessed Jun. 27, 2023).
[3] Technical data sheet bergquist liqui bond TLB SA2000, https://datasheets.tdx.henkel.com/BERGQUIST-LIQUI-BOND-TLB-SA2000-en_US.pdf (accessed Jun. 27, 2023).
[4] 832TFF – MG chemicals, https://www.mgchemicals.com/downloads/tds/tds-8329tff-2parts.pdf (accessed Jun. 27, 2023).
[5] CoolTherm® MT-322 thermally conductive adhesive – parker, https://ph.parker.com/us/en/product/cooltherm-mt-322-thermally-conductive-adhesive/cooltherm-mt-322 (accessed Jun. 27, 2023).
[6] Thermal interface materials (tims): Product overview – wacker, https://www.wacker.com/h/en-us/medias/7935-EN.pdf (accessed Jun. 27, 2023).
[7] 3MTM thermally conductive epoxy adhesive TC-2810, https://multimedia.3m.com/mws/media/266197O/3mtm-thermally-conductive-epoxy-adhesive-tc2810.pdf (accessed Jun. 27, 2023).
About the Author
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Landen MacDonald Marketing Intern Landen MacDonald is a marketing intern at C-Therm Technologies. He is currently in his third year of Chemical Engineering at the University of New Brunswick. |