ELECTRONICS
SIC SHIFT T
he move towards 800V and above in electric vehicles (EVs) is well underway, with automotive OEMs
such as General Motors, Hyundai and Volkswagen leading the way in this area. Facilitated largely by advancement in silicon carbide (SiC) MOSFETS, these platforms enhance efficiency by minimising joule losses and allowing for the downsizing of high-voltage cabling, thereby reducing weight. SiC MOSFETs possess an improved ability to support high- frequency switching at higher voltages and, in comparison to Si IGBTs, offer smaller die areas and higher junction temperatures which require more effective thermal management. Observing this challenge, IDTechX
Senior Technology Analyst Yulin Wang has produced a report on the adoption of SiC MOSFETs in EV power electronics, including various emerging thermal management strategies. These include transitioning to direct liquid cooling employing a pin-fin structure, using double- sided cooling, replacing solder alloys with silver or copper sintered paste, employing thermal interface materials with high thermal conductivity, and replacing aluminium wire bonds with copper alternatives.
IDTechX evaluates thermal material trends driven by SiC adoption in electric vehicle power electronics
THERMAL MANAGEMENT New methods of thermal management are currently emerging, ranging from altering thermal architecture to utilising different die-attach materials and thermal interface materials (TIMs). According to Wang, this shift is likely to present significant opportunities in the thermal management market, propelling the annual market value of TIMs to surpass $900 million by 2034. TIMs are commonly applied
between the baseplate and the heatsink. IDTechX’s report anticipates a surge in demand for TIMs with higher thermal conductivity due to the escalating heat flux of SiC MOSFETs. As of 2024, the typical thermal conductivity of such a TIM ranges from 2.5-3W/mK, with expectations for this to exceed 5 or 6W/mK in some cases by 2034. As a result, we could see a proportional rise in unit price alongside an increase in the market value of these types of TIMs.
DIE-ATTACH AND SUBSTRATE-ATTACH MATERIALS Conventional die-attach and substrate-attach materials typically consist of solder alloys featuring
Trend towards Sintering
bondline thicknesses ranging from 50-100µm for the former and 100- 150µm for the latter. Despite their satisfactory performance, IDTechX has observed a growing preference for Ag sintering, led by major automotive OEMs such as Tesla. Ag sintering, in comparison to traditional solder alloys, offers superior thermal and electrical conductivity and enhanced bond strength among other benefits. However, due to its higher costs and processing times, Ag sintering is likely to see primary adoption in applications that really require its benefits, such as wide bandgap-based inverters. As Wang states, the cost of Ag
sintering can vary significantly due to a number of factors, with the cost of Ag sintered paste easily being five to ten times higher than that of solder alloys. Despite this, the report reveals a discernible trend towards replacing solder alloys with Ag sintering pastes from automotive manufacturers. To address the cost factor, Cu sintering is proposed as an alternative approach, Wang says. Compared to Ag sintering, Cu
sintering aims to offer similar performance but at a lower cost. However, IDTechX has not observed widespread commercialisation of Cu sintering technology in EV power modules as of yet. This could be due to the fact that, as a result of limited volume and technical challenges, the cost of Cu sintering currently often surpasses that of Ag sintering.
For further information, read the full report: ‘Thermal Management for EV Power electronics 2024-25: Forecasts, Technologies, Markets and Trends.’
www.idtechx.com
40
www.engineerlive.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48
