New guidance from testing and certification specialist TÜV SÜD has highlighted the potential need for product redesign as UK electronics manufacturing suppliers to EU markets prepare for battery removability and replaceability requirements taking effect on 18 February 2027.
Published in October, the guidance warns that manufacturers may need to change product enclosures, battery fixings and access mechanisms, while stressing that exemptions are not automatic.
Under Article 11 of the EU Batteries Regulation (EU) 2023/1542, portable batteries incorporated into affected products must generally be readily removable and replaceable by end-users, subject to specified exceptions and derogations, including circumstances where replacement by an independent professional is permitted.
For compact electronics, making room for removable batteries, connectors and access mechanisms could leave less space for the printed circuit board (PCB), prompting manufacturers to consider reducing its footprint. Drawing on decades of experience designing space-constrained electronics, Birmingham-based engineering consultancy ByteSnap Design has identified five design trade-offs manufacturers should consider when exploring PCB miniaturisation.
Five PCB design trade-offs when making room for replaceable batteries
1. Review product architecture and battery access
Creating room for a replaceable battery does not automatically justify reducing the PCB footprint. Higher circuit density may require additional board layers, more complex routing or HDI fabrication, potentially increasing cost without delivering a worthwhile saving in overall product space. Engineers should establish whether changes to battery positioning or enclosure design could achieve the required access before introducing unnecessary complexity into the electronics.
2. Design the thermal path, not just the PCB layout
Shrinking a PCB reduces the copper available to spread heat, making thermal management particularly challenging in fanless enclosures. Thermal vias can move heat between PCB layers, but they cannot solve the problem alone if there is insufficient copper to spread it or no effective route for heat to escape. Engineers should consider thermal via arrays beneath exposed component pads, heavier internal copper and thermal interface materials together, ensuring heat can travel from the component through the board and into the enclosure.
3. Look beyond routing density when selecting HDI technology
High-density interconnect (HDI) technology can recover valuable board space, but the microvia structure can determine whether a compact design is reliable in production. Stacked microvias place greater demands on copper plating and the integrity of the connections between layers, making them more vulnerable to defects that may only emerge during thermal cycling. Staggered microvias can offer a more robust, cost-effective alternative where the layout permits. Engineers should also check microvia depth-to-diameter ratios with their fabricator: keeping these at or below 1:1, and preferably around 0.75:1, can improve plating reliability.
4. Watch for hidden EMC problems in compact layouts
A routing change intended to save space can increase electromagnetic emissions if it interrupts the return path beneath a high-speed signal, potentially creating common-mode noise or unintended radiation. Sensitive analogue circuits can also suffer when placed too close to high-performance digital components. In the Cocoon smart-home security system, engineers had to keep the microphone circuitry away from the processor to protect its audio noise floor. They also allowed for additional EMI shielding during development, although the board ultimately passed CE, FCC and R&TTE testing without it. The lesson is to plan signal separation and EMC mitigation before the layout becomes too constrained to accommodate them.
5. Calculate the cost of the product, not just the PCB
A smaller PCB can cost more to fabricate yet still reduce the overall cost of a product. Industry estimates suggest HDI fabrication can cost 20–60% more per panel than conventional multilayer boards with an equivalent layer count, but that premium needs to be weighed against potential savings in enclosure materials, assembly and other components. Fine-pitch packages and smaller components can also introduce hidden production costs, including reduced assembly yields and additional inspection requirements. Engineers should therefore compare complete manufacturing costs at the intended production volume rather than judging HDI on PCB fabrication costs alone.
Dunstan Power, co-founder and director of ByteSnap Design said: “The February 2027 requirements bring renewed attention to an important aspect of electronic product development: how products can be maintained throughout their working lives. It’s a consideration that deserves attention alongside the performance and reliability requirements that manufacturers already have to meet.”
Research from Mordor Intelligence identifies demand for miniaturisation and HDI PCBs, particularly in wearable and Internet of Things (IoT) applications, as a driver of the European PCB market. Its Europe Printed Circuit Board Market report forecasts annual growth of 3.28% across Europe between 2026 and 2031, with the UK projected to record the fastest growth among the countries analysed, at 4.34% annually. These figures relate to the overall PCB market, rather than miniaturised boards specifically.
