Electric vehicle (EV) innovation is defined by one trend, more power in less space.
From traction inverters to DC-DC converters and onboard chargers, power electronics are being pushed toward higher power density, tighter packaging and lighter weight. These systems sit at the heart of EV performance, controlling energy flow between battery, motor and auxiliary systems.
That said, a new set of engineering constraints emerges as packaging shrinks and power increases. And more often, those constraints show up in semiconductors or cooling systems as well as the mechanical joints that hold everything together.
As power electronics shrink, the physical space available for fastening and structural support reduces alongside them. Thread engagement lengths become shorter, access for tooling becomes more restricted and the margin for installation variability narrows.
At the same time, the loads acting on those joints are increasing. Power electronics assemblies are exposed to rapid thermal cycling, vibration from vehicle operation and the need to maintain stable interfaces for heat transfer. Maintaining consistent clamp force across cooling plates, substrates and housings is critical, because even small deviations can affect thermal resistance and long-term reliability.
This creates a fundamental imbalance. Engineers are being asked to deliver greater mechanical reliability from smaller, lighter and more constrained joints.
Traditional threaded solutions struggle to meet that requirement. Threads cut directly into aluminium housings or lightweight castings are vulnerable to wear, deformation and preload loss, particularly under repeated thermal expansion and contraction. Over time, this can lead to joint relaxation, inconsistent performance and increased maintenance risk.
In compact EV systems, where assemblies are densely integrated and difficult to access, these issues are not isolated. They affect the reliability of the entire system.
Thermal management is one of the defining challenges of EV power electronics. Maintaining stable temperatures across components is essential to performance, efficiency and lifespan.
However, thermal performance is not just a function of cooling design. It depends heavily on mechanical consistency. Interfaces such as cold plates and heat spreaders rely on uniform clamping force to ensure effective heat transfer. If preload varies, thermal interface materials can compress unevenly, leading to hotspots and reduced efficiency.
Studies into EV thermal systems emphasise the importance of stable mechanical interfaces in maintaining consistent temperature control, particularly under high-power operation and fast charging conditions.
As packaging becomes more compact, the tolerance for variation in these interfaces decreases. This means that joint behaviour (particularly preload consistency over time) becomes an important design factor rather than a secondary consideration.
Miniaturised wire thread inserts address this challenge by changing how the joint behaves at its most fundamental level.
Instead of relying on the parent material to carry thread loads, inserts introduce a dedicated, hardened thread interface that distributes stress more evenly and resists wear. This is particularly valuable in lightweight materials such as aluminium, which are widely used in EV power electronics for their thermal and weight advantages but are less resistant to thread damage.
In compact assemblies, this reinforcement delivers several key benefits:
The benefits of miniaturised inserts go beyond performance in service. They also play a role in how EV power electronics are manufactured at scale.
As production volumes increase, variability becomes a critical issue. Small inconsistencies in torque application or thread condition can translate into large-scale quality challenges across thousands of units. Standardised threaded interfaces help reduce this variability, supporting more predictable assembly processes and improving repeatability.
Tangless® inserts offer an additional layer of process control. By eliminating the need for tang break-off, they remove a step from installation and avoid the risk of debris in sensitive electronic assemblies. This is particularly relevant in compact power electronics, where contamination can have disproportionate consequences.
As EV architectures continue to evolve, the pressure to increase power density and reduce system size will only intensify. This places growing importance on the mechanical integrity of compact assemblies. The challenge is to ensure that they remain reliable under higher loads, tighter constraints and more demanding operating conditions.
Miniaturised wire thread inserts provide a way to meet that challenge. By reinforcing the joint at the thread level, they allow engineers to maintain strength, consistency and serviceability without compromising on weight or packaging efficiency.
KATO Advanex applies decades of aerospace-proven expertise to the design of wire thread inserts for high-performance applications. Our Tangless® and tanged inserts are engineered to support consistent preload in compact assemblies, durability under thermal cycling and vibration and reliable performance in lightweight materials
As EV power electronics become more compact and more demanding, joint design becomes a critical enabler of system performance. KATO supports engineers in delivering that reliability, ensuring that mechanical integrity keeps pace with advances in electrification. To find out more, download out guide below.