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How to Spec EV Charger Thermal, EMI and Sealing Parts: What to Send H-O for a Quote
A fast, accurate quote on a die-cut charger part comes down to nine inputs: the job at each location (thermal interface, EMI shielding, environmental sealing, or venting), the power to dissipate with the bond-line and clamping pressure for a TIM, whether the interface must electrically isolate the device, the target ingress class under IEC 60529, whether the charger must meet CISPR 11 emissions, the outdoor environment and temperature range, the geometry or drawing, the adhesive configuration, and your volumes.
This guide walks each input, explains why it matters, and ends with a spec builder that assembles your answers into a request you can paste straight into the contact form.
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The application problem: an incomplete spec stalls the quote
H-O Products is a precision die-cut converter, and every thermal pad, gasket, seal and vent patch is made to order from sheet, slab or roll stock cut to your drawing. The concrete problem a buyer runs into is the stalled quote: a request that says "I need a thermal pad for a charger" without the heat, the gap or the isolation answer cannot be turned into a grade and a price without a follow-up.
The inputs below are the same ones an applications engineer would ask for, so sending them up front turns a back-and-forth into a single response.
The first input does the most work. As covered in the companion guides on TIM selection and enclosure design, the part is doing one of four jobs: thermal interface (move heat from a module to a sink), EMI (keep a shield-boundary seam electrically continuous), sealing (close a cabinet joint toward the ingress class), or venting (equalize pressure while staying sealed to liquids). The rest of the spec branches from that answer.
Why it is challenging: the values come in linked pairs, and the equipment owns the ratings
Charger-part specs fail in pairs: a wattage without the bond-line and clamping pressure, an IP class without the groove detail, a shield requirement without the seam map, a vent with no cabinet volume. Each pair is needed together because the second member sets what the first can mean in practice. And the headline ratings, the IP class per IEC 60529, the emissions result per CISPR 11, and conformance of the charging equipment under IEC 61851, belong to the tested cabinet and system, with the converted parts supporting them.
The checklist below is organized around those realities.
What to send, input by input
1. The job at each location
List the locations with their functions: thermal interfaces at the power modules, EMI gasketing on shield-boundary seams, environmental seals at doors and panels, and the vent port. The four jobs map to graphite TIM or boron-nitride pads, conductive EMI silicone, EPDM foam and ePTFE membrane respectively.
2. Power, bond-line and clamping pressure (for a TIM)
Send the heat to move, the measured gap and flatness, the achievable clamping pressure and the bond-line. ASTM D5470 data is generated under defined conditions, so your real interface details are what let the grade be matched to your thermal budget rather than to the test fixture.
3. The isolation answer
State whether each thermal interface must electrically isolate the device from the sink. This single answer rules graphite in or out before any thermal comparison, and for isolated joints it adds the breakdown-voltage line to the spec.
4. Target ingress class
Name the class under IEC 60529 for the cabinet, and send the joint detail with it: groove width and depth, fastener pattern, closure force. The class is reached by the whole joint and verified on the tested enclosure.
5. CISPR 11 context and the seam map
Say whether the charger must meet CISPR 11 and which seams sit on the shield boundary. That places conductive gaskets only where they earn their cost and keeps plain EPDM everywhere else.
6. Outdoor environment and temperature range
Describe the exposure: sun load, rain and wash, ozone, the daily temperature swing, and for the vent, the cabinet volume. The swing and volume size the vent; the exposure confirms the seal family.
7. Geometry, footprint, or a drawing
A dimensioned drawing (DXF, STEP or PDF) is the cleanest input: module footprints with cutouts for posts and fasteners, gasket paths with corner detail, vent port size and location. A marked-up sketch with dimensions is enough to start a prototype.
8. Adhesive, liner and kitting
Tell us which parts need a pressure-sensitive adhesive, a liner, a pull-tab, or kiss-cut presentation, and whether the program wants the TIM, gaskets, seals and vent patches kitted per cabinet. Adhesive options vary by grade, conductive grades especially.
9. Prototype and annual volume, and a target date
Share the prototype quantity, the expected annual volume, and any target ship date. All parts are custom manufactured to order, and minimum production run quantities apply, so the volume shapes the converting approach and the tooling decision. Prototype quantities through full production are welcome.
The spec at a glance
| Input | TIM | EMI gasket | Enclosure seal | Vent |
|---|---|---|---|---|
| Performance target | Heat + bond-line + pressure; isolation yes / no | Seam role under CISPR 11 | IP class per IEC 60529 | Cabinet volume + temperature swing |
| Environment | Outdoor exposure; temperature range; wash and ozone | |||
| Joint detail | Gap and flatness | Groove W x D; fastener pattern; closure force | Port diameter and location | |
| Build | Adhesive, liner, kiss-cut presentation; kitting per cabinet; thickness or range | |||
| Geometry | Footprints or dimensioned drawing (DXF / STEP / PDF) | |||
| Commercial | Prototype quantity + annual volume + target date | |||
Charger Thermal / EMI / Sealing RFQ Spec Builder
Job: Thermal interface (power module) Heat / bond-line / pressure: [to be provided] Isolation: [to be provided] Ingress class: [to be provided] CISPR 11 context: [to be provided] Environment: [to be provided] Joint / groove / port: [to be provided] Geometry: [to be provided] Build: standard die-cut; thickness [to be provided] Commercial: prototype quantity [to be provided]; annual volume + date [to be provided] Drawing: to follow
Illustrative only; confirm against current material data and a drawing review. This builder formats your inputs into a request; it does not select a grade, compute a thermal impedance, or assert an IP or emissions result. Material values are confirmed on the manufacturer's current technical data sheet and in an H-O drawing review, and the IP class, emissions result and charger conformance belong to your tested cabinet and system per IEC 60529, CISPR 11 and IEC 61851.
Common failure modes in the spec itself
| Spec gap | Why it stalls the quote | The fix |
|---|---|---|
| Wattage with no interface condition | In-application impedance depends on gap, flatness and pressure | Send the heat and the interface condition together |
| No isolation answer | Graphite is ruled in or out by this single question | State whether the TIM must isolate the device |
| IP class with no joint detail | The class is reached by the whole joint | Send groove, fasteners and closure force with the class |
| "Shielded cabinet" with no seam map | Conductive gaskets belong only on shield-boundary seams | Mark which seams carry the shield |
| Vent request with no volume or swing | The vent area follows from both | Send cabinet volume, temperature swing and port detail |
| No volumes | The converting and tooling approach depends on prototype versus production scale | Send both prototype quantity and annual volume |
How H-O Products helps
H-O Products is a precision die-cut converter working across EV and battery programs.
Once your spec is complete, we recommend a family and grade direction across graphite thermal interface material, boron-nitride silicone pads, SSP502 conductive EMI silicone (die-cut as the 2368 conductive silicone (SSP502 family)), EPDM foam and ePTFE venting membrane, then convert the stock to your drawing: die-cut, kiss-cut, laser or waterjet cut, laminated, adhesive-backed on liners, and kitted per cabinet.
Documentation available on request includes the material technical data sheet, a certificate of conformance, lot traceability, and first-article inspection, all under our ISO 9001:2015 certified quality management system. We do not produce the raw stock and we do not certify the finished assembly; the IP class, emissions result and charger conformance belong to your tested equipment.
Send the spec, get a quote
Use the builder above to assemble your request, then send it through the contact page with your drawing attached. We will recommend a grade direction and convert samples on your geometry.
Samples typically ship in 3 to 5 business days for common die-cut configurations; standard production runs about two weeks; special orders are quoted to the job.
Family-owned in Winsted, Connecticut since 1971 · ISO 9001:2015 certified · OEMs worldwide send us a drawing — and get back their part.
Related reading
ApplicationEV Charging Infrastructure Thermal, EMI & SealingRead →
GuideGraphite or Boron Nitride? Choosing the Thermal Interface for EV Charger Power ModulesRead →
GuideSealing an Outdoor EV Charger: IP Classes, Pressure Pumping and the EMI QuestionRead →
IndustryEV & Battery materials overviewRead →
Frequently asked questions
What information should I send to get a useful charger material recommendation?
Five things move a recommendation from a guess to a real direction: the job at each location (thermal interface, EMI shielding, environmental sealing, or venting), the power to dissipate with the bond-line and pressure for a TIM, whether a thermal interface must electrically isolate the device, the target ingress class under IEC 60529 for an outdoor enclosure, and whether the charger must meet CISPR 11 emissions.
Add the geometry or a drawing, the adhesive needs, the outdoor environment, and the volumes, and engineering can match a family and grade direction in one pass.
Why does a TIM spec need the bond-line and clamping pressure, not just the wattage?
Because the in-application thermal impedance depends on exactly those conditions. ASTM D5470 characterizes a TIM under defined test conditions; your interface runs at its own pressure, flatness and bond-line, which is why real interfaces often run warmer than the headline number. The wattage says how much heat must move; the interface condition says what the material can actually deliver in your stack.
Does H-O make the raw thermal and sealing materials, and is there a minimum order?
H-O is a precision die-cut converter, not a raw-material producer. We buy graphite, silicone, EPDM foam and membrane stock from the material manufacturers and convert it to your drawing by die-cutting, kiss-cutting, laser and waterjet cutting, lamination, slitting and kitting. Every part is made to order; minimum quantities vary by material and part, and prototype quantities through full production runs are equally welcome.
Request a quote for your EV charging infrastructure part
Send H-O your drawing or describe the part—engineering reviews every RFQ and converts samples on your geometry.
Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).
References
- ASTM D5470, Standard Test Method for Thermal Transmission Properties of Thermally Conductive Electrical Insulation Materials. ASTM International.
- IEC 60529, Degrees of Protection Provided by Enclosures (IP Code). International Electrotechnical Commission.
- CISPR 11, Industrial, scientific and medical equipment: radio-frequency disturbance characteristics, limits and methods of measurement. CISPR / IEC.
- IEC 61851, Electric vehicle conductive charging system. International Electrotechnical Commission.
This article cites general engineering principles and published standards (ASTM D5470 for thermal-interface characterization, IEC 60529 for ingress protection, CISPR 11 for industrial-equipment emissions, IEC 61851 for EV charging systems). Material names refer to material families H-O Products converts. Thermal, sealing, conductivity and airflow values are grade-specific and application-dependent; confirm all values against the manufacturer's current technical data sheet and an engineering drawing review.
IP classes, emissions results and charger conformance belong to the tested cabinet, charger and system. All parts are custom manufactured to order and minimum production run quantities apply. H-O is a die-cut converter, not a raw-material producer, and does not certify the finished assembly.