I. Overview of the Plan
In-vehicle electronic control systems comprise core components, including the vehicle-wide ECU controller, motor controller, BMS (Battery Management System), in-vehicle industrial control motherboard, ADAS (Advanced Driver Assistance System) module, and Body Control Module (BCM). These components are classified as automotive safety-grade electronic parts and are continuously exposed to harsh operating conditions, such as high and low temperature fluctuations, high-intensity vibration, moisture and dust, as well as oil contamination and corrosion.
Adhesives for automotive electronics must comply with automotive-grade standards (AEC-Q100/AEC-Q200), exhibit wide-temperature tolerance from-40 °C to 125 °C, provide moisture-proof insulation, withstand vibration, feature low VOC content, be non-corrosive, and resist aging; also, they must fulfill five core requirements: waterproof sealing, thermal conductivity and heat dissipation, structural reinforcement, chip protection, and circuit insulation.
II. Core application station disassembly (fully electrically controlled, universal application)
1. In-vehicle electronic control systems: housing structure bonding and sealing: joint sealing of plastic/metal housings, cover plate sealing, and connector base fixation
2. PCB component mounting: vibration-proof reinforcement for capacitors, resistors, chips, and connectors
3. Chip underfill: Underfill application for BGA, CSP, and FlipChip chips to mitigate thermal expansion/contraction effects and prevent solder joint detachment.
4. Full-chassis/Module hermetic encapsulation: full PCB encapsulation, coil encapsulation, and high-voltage module insulation protection
5. Thermal interface filling: thermal bonding of chips, MOSFETs, power devices, and thermal gaskets
6. Three-Protect Coating: Moisture-proof, salt-spray-proof, and oil-stain-proof insulation protection for entire PCBs
7. Sealed fastening of wiring harnesses, terminals, and plugs: resistance to pulling, waterproofing, and oxidation protection
III. Adhesive Application Scheme by Functional Position (Automotive-Grade Selection)
1. Housing bonding in in-vehicle electronic control systems: joint sealing (ECU/BCM/MCU housings)
Operating conditions: ABS/PC/aluminum alloy housing; subjected to prolonged vibration and alternating temperature fluctuations; requires waterproof and dustproof properties, resistance to adhesive delamination, and crack resistance.
Recommended sealant type: Single-component modified silane MS sealant / high-temperature resistant silicone sealant
Key advantages: solvent-free, low odor, non-corrosive, resistant to extreme temperatures (-50 °C to 150 °C), elastic and vibration-resistant, repairable, compatible with a wide range of materials, complies with environmental requirements for automotive interiors, and does not corrode PCBs or metal contacts.
Prohibited: ordinary glass adhesive, low-quality PU adhesive (prone to yellowing, corrosion, and aging-induced cracking)
2. PCB component reinforcement (small components, connectors, terminal fixation)
Operating conditions: The vehicle experiences roughness and vibration, which can easily lead to cold solder joints, component detachment, and pin breakage.
Recommended adhesive types: UV-curable reinforcing adhesive / low-temperature rapid-curing epoxy spot-curing adhesive
Key advantages: instant curing of UV adhesive, compatibility with automated production lines, precise positioning, and stress-free application; the epoxy spot-curing agent offers high bonding strength, high temperature resistance, and is ideal for reinforcing opaque components. After curing, it provides vibration resistance, prevents detachment, and exhibits excellent resistance to temperature and humidity.
3. Chip Underfill (high-end electronic control core process)
Operating conditions: For BGA, CSP, and FlipChip main control chips, temperature cycling can readily induce solder joint stress failure, making these chips a high-risk point for electronic control system failures in automotive applications.
Recommended resin type: Automotive-grade underfill epoxy resin
Key advantages: low viscosity self-leveling properties, rapid filling of micro-gaps beneath the chip, low coefficient of thermal expansion, high temperature resistance, and ability to absorb thermal stress—collectively preventing solder joint cracking caused by extreme temperature cycling in automotive applications, thereby significantly extending the service life of the controller.
4. Full-plate/Module encapsulation and insulation protection
Operating conditions: high-voltage electronic control, battery management system (BMS), and motor drive module; requires complete insulation, waterproofing, oil resistance, and arc resistance.
Option A (Cost-effective general-purpose): Two-component epoxy potting compound
It features high hardness, exceptional electrical insulation properties, high voltage resistance, and chemical corrosion resistance, making it ideal for the encapsulation of fixed power modules and coils.
Option B (Preferred choice for high-end automotive applications): Silicone flexible potting compound
Featuring flexible encapsulation, extremely low stress, high-temperature resistance, and no board cracking or delamination, this material is suitable for automotive high-frequency vibration and extreme temperature cycling conditions. It is also repairable, making it the mainstream solution for electronic control systems in new energy vehicles.
5. Thermal bonding for power device heat dissipation
Operating conditions: MOSFETs, IGBTs, and the main control chip generate significant heat; elevated temperatures can lead to frequency reduction, system crashes, or device burnout.
Recommended silicone type: Thermal conductive silicone adhesive / Thermal conductive gel
Key advantages: Combines adhesive fixation with thermal conductivity and heat dissipation; enables precise alignment between the chip and the heat-dissipating aluminum plate, fills micro-gaps to rapidly dissipate heat, and exhibits resistance to aging and pulverization across extreme temperature ranges.
6. PCB hermetic coating (general protection for vehicle electronic control systems)
Operating conditions: moisture, salt spray, exhaust oil contamination, and condensate may cause electrical leakage, short circuits, and corrosion.
Recommended resin type: Acrylic/Silicone conformal coating (automotive grade)
Key advantages: ultra-thin film formation, insulation and moisture resistance, corrosion resistance, and high/low temperature durability—all without compromising electrical performance—effectively addressing the issue of moisture-induced failure in vehicle electronic control systems under prolonged outdoor and chassis operating conditions.
7. Sealing and securing of wiring harness terminals
Recommended sealant types: flexible silicone hole-sealing sealant, rapid-curing reinforcing sealant
Waterproof sealing for wiring harness ports and terminal connectors; resistant to pulling forces and moisture-induced oxidation; designed to withstand prolonged vibration in automotive environments.
IV. Reference Table for Selection of Adhesives for In-Vehicle Electronic Control Systems (Ready for Direct Implementation)
| Application workstation | Recommended adhesive type | Core Features | Operating Condition Adaptability Features |
| ECU housing sealing and jointing | MS-modified silane/silicone sealant | Waterproof and dustproof, shock-absorbing and vibration-resistant, weather-resistant | Reparable, non-corrosive, wide temperature range tolerance |
| Reinforcement of small PCB components | UV-reinforcing adhesive / epoxy spot-curing adhesive | Vibration-resistant, anti-detachment, and position-fixed | Automated mass production, high precision |
| Underfill for BGA chips | Epoxy Underfill | Eliminate thermal stress and protect the weld joints | Addressing failure due to thermal cycling in solder joint detachment |
| Overall potting of the electronic control module | Flexible silicone potting compound | Insulation, waterproofing, shock resistance, and anti-aging properties | Mainstream new energy vehicle solutions, no panel cracking |
| Thermal Conductivity and Heat Dissipation of Power Devices | Thermal conductive silicone/gel | Dual functionality: adhesion and thermal conductivity | Resistant to prolonged high temperatures without failure |
| Full-plate three-way protection | Automotive-grade triple-protection paint | Moisture-proof, salt spray-proof, and corrosion-resistant | Compatible with chassis and designed for outdoor vehicle operating conditions |
V. Adhesive Hardness Standards for Automotive Electronics (Mandatory for automotive applications)
1. Adhesive temperature tolerance for in-vehicle electronic control systems: stable operating range from –40 °C to 125 °C; no cracking, delamination, or failure observed during thermal cycling.
2. Electrical Performance: High insulation, low dielectric loss, absence of conductive impurities, and no interference with signal transmission
3. Environmental Resistance: Resistance to oil contamination, moisture, salt spray, and automotive cleaning agents.
4. Reliability: Resistant to high-frequency vibration and mechanical impact; maintains structural integrity without aging or pulverization during prolonged in-vehicle service.
5. Environmental Compliance: Low VOC content, halogen-free, and compliant with automotive REACH and RoHS standards
VI. Common Failure Issues and Key Considerations for Avoiding Pitfalls
1. ❌ In-vehicle electronic control systems prohibit general industrial adhesives: conventional epoxy and conventional rapid-curing adhesives lack sufficient temperature resistance, can corrode pins, fail to pass automotive-grade testing, and may lead to widespread failure in later stages of application.
2. ❌ High-temperature chips should not be encapsulated with rigid, thick compounds: the thermal expansion and contraction of rigid resins can tear the PCB and sever solder joints; instead, flexible encapsulation or thermally conductive flexible adhesives must be used.
3. ❌ No underfill for BGA chips: Given the significant temperature and vibration variations in automotive environments, the absence of underfill can easily lead to solder joint failures, system crashes, and black screen failures.
4. ❌ Using rigid rubber seals for the housing: Due to body vibrations and thermal expansion/contraction, seams in rigid rubber seals are highly prone to cracking and water ingress; therefore, an elastic sealing system must be employed.
VII. Summary of the Plan
The core adhesive selection criteria for in-vehicle electronic control systems are as follows: for structural sealing, elastic MS/silicone rubber; for component reinforcement, UV/epoxy spot-curing adhesive; for chip protection, underfill; for module protection, flexible silicone potting compound; for thermal management, thermal conductive adhesive; and for overall board protection, conformal coating. This complete solution fully complies with automotive-grade reliability requirements for all electronic control modules in both conventional internal combustion engine vehicles and new energy vehicles, is compatible with automated mass production, and addresses four critical challenges: vibration, high temperature, moisture ingress, and solder joint failure.
Everything covered here draws on the full JOME product catalogue JOME manufactures in house. Engineers comparing notes with Adhesive Solutions for Public Transportation can move between the two guides; the the full JOME bonding solutions line frames the range and the send drawings to the JOME team takes it from there.