EV programs don’t “cast everything.” In practice, aluminum die casting shows up where you need structure + packaging efficiency + repeatability—especially in parts that must survive heat, vibration, and long-term corrosion while keeping weight under control.
If you’re new to EV sourcing, here’s the simplest rule:
Most EV castings are housings, covers, enclosures, brackets, and manifolds—parts that protect electronics, manage sealing, support thermal paths, or carry mechanical loads.
This guide shows what EV parts are commonly aluminum die cast, why they’re cast, and the specs that matter most if you want a quote that matches real performance.
Quick answer: the five EV casting zones you’ll see again and again
Across platforms, die-cast aluminum parts typically cluster into five zones:
- Power electronics housings: inverter, onboard charger, DC-DC
- E-drive housings: motor housing, gearbox housing, end covers
- Battery enclosure structures: tray sections, rails, end plates, covers
- HV distribution enclosures: PDU/junction box housings, shields, mounts
- Thermal management castings: manifolds, valve bodies, pump housings, plates
If your part lives in one of these zones, it’s a strong candidate for aluminum die casting.
Common EV die cast parts and what they require selection table
Use this table as a fast checklist when you’re deciding whether a part is “castable” and what will drive cost and risk.
| EV part category | Typical examples | Why aluminum is used | Critical specs to quote | Common failure risks | Recommended process notes |
|---|---|---|---|---|---|
| Power electronics housings | Inverter housing, OBC housing, DC-DC housing, covers | Thermal path, EMI shielding, structural protection | Flatness of sealing face, machining datums, coating stack, grounding points | Porosity leaks, warpage, coating undercut | Consider vacuum die casting if sealing is strict; define cosmetic zones early |
| E-drive housings | Motor housing, gearbox housing, end covers | Complex geometry + stiffness-to-weight | Bearing bore position, coaxiality, critical fits, machining scope | Distortion after machining, cracks near bosses | Early datum strategy is key; avoid over-thin ribs near load points |
| Battery enclosure structures | Tray parts, side rails, end plates, covers | Structure, corrosion resistance, packaging | Sealing strategy, flatness, threaded inserts, coating and isolation | Galvanic corrosion, leak paths, bolt pull-out | Define insulation and isolation features; clarify torque specs and inserts |
| HV distribution enclosures | PDU/junction box housings, shields, brackets | Protection, mounting, EMI, sealing | IP target, gasket/O-ring details, screw bosses, sealing surfaces | Water ingress, boss cracking, poor lid flatness | Define gasket compression and surface finish expectations |
| Thermal management castings | Manifold blocks, valve bodies, pump housings | Flow integration, corrosion resistance, compact packaging | Leak target, port threads, pressure/temperature media, cleanliness | Porosity, corrosion pitting, thread issues | Specify media and corrosion requirements; define cleanliness level if needed |
Why these EV parts are cast instead of fabricated or fully machined
Most EV housings aren’t cast because “casting is cheap.” They’re cast because casting lets you integrate functions that would otherwise become multiple machined parts and fasteners.
Casting helps you integrate complexity
Ribs, bosses, mounting ears, cable routing supports, and sensor pockets can be formed in one shot instead of as added brackets or welded features.
Casting supports stiffness with controlled mass
A good housing uses thin walls where possible and local reinforcement where needed. You get structure without turning everything into thick plate.
Casting plays well with thermal and EMI requirements
Electronics housings often want a stable thermal path and a conductive enclosure for EMI control. Aluminum housings are commonly selected for those combined reasons.
Casting scales repeatability at volume
Once a tool and process window are stable, you can scale consistent geometry at production volumes and keep machining focused on only the critical surfaces.
What specs matter most for EV housings and enclosures
If you only remember one thing: EV housings succeed or fail on interfaces—sealing, flatness, datums, and surfaces.
Sealing and leak expectations
If a housing must be sealed, define:
- Sealing method: gasket, O-ring, RTV, potting, or mixed
- Sealing face requirements: flatness, surface condition, and any “no-porosity” zone callouts
- What the seal is protecting against: water spray, immersion, coolant, oil mist, salt, dust
Flatness and distortion control
Flatness is not just a machining note—it affects:
- gasket compression consistency
- IP performance
- torque retention
- long-term vibration durability
A drawing that says “flatness critical” without identifying the datums and mating strategy often leads to rework loops.
Datums and machining strategy
For complex housings, the best sourcing outcomes happen when you define:
- primary datums (A/B/C)
- what surfaces are machined
- what stays as-cast
- how critical bores and sealing faces relate to those datums
This avoids the common problem: “we held the dimension, but the assembly still doesn’t fit.”
Threads, inserts, and pull-out strength
Be explicit about:
- thread type and engagement length
- use of steel inserts or helicoils
- torque requirements and any repeated service cycles
Thread pull-out is a common late-stage issue when inserts and torque targets were never aligned up front.
Surface, corrosion, and coating stack
EV components see harsh environments:
- road salt
- humidity cycling
- coolant splash
- dissimilar metal contact
Define coating expectations (or the test you care about), and note where conductivity is required (EMI ground points) so coatings don’t block the function.
Typical failure modes and how teams prevent them
EV casting failures are usually not “mystery problems.” They repeat in patterns.
Porosity that turns into leaks
What you see: failed leak test, seepage around sealing faces, coolant/oil weeping.
What causes it: gas entrapment, insufficient venting, poor process window, thick-to-thin transitions.
What helps: process control, gating/venting improvements, tighter melt and die temperature control, and vacuum die casting when sealing is stringent.
Warpage and lid mismatch
What you see: a lid that won’t seal evenly, inconsistent gasket compression, torque loss.
What causes it: thermal imbalance, thin-wall distortion, machining removing stress unevenly.
What helps: stabilize wall thickness, improve cooling balance, tighten fixture strategy, and define realistic flatness zones.
Cold shuts and misruns in thin-wall zones
What you see: seam-like defects, incomplete fusion, weak points near flow meeting lines.
What causes it: temperature loss and low filling energy, long flow lengths, poor venting.
What helps: improve fill pattern, shorten flow, adjust gate location and overflow design, and stabilize die temperature.
Cracks near bosses and sharp transitions
What you see: boss cracking during assembly or vibration life.
What causes it: stress concentration, thin ligaments, excessive torque, or poor fillets.
What helps: redesign boss geometry, add fillets, adjust rib paths, and align torque specs with insert strategy.
Galvanic corrosion and coating failures
What you see: pitting, white corrosion products, coating undercut near fasteners.
What causes it: dissimilar metal contact in salty environments, damaged coatings, trapped moisture.
What helps: isolation design, correct coating stack, controlled contact points for grounding, and drain/vent paths where moisture can collect.
Quality control: what buyers should ask for
If you want production stability, ask for evidence—not promises.
A practical EV housing QC set often includes:
- CMM reports for key datums and interfaces
- Leak verification approach for sealed parts (method and acceptance criteria defined by the program)
- Process traceability at lot/batch level
- Visual standard for cosmetic zones
- Coating verification plan if corrosion performance matters (what gets measured, where)
Even one sentence on the PO like “sealing face is functional, cosmetic not required” can prevent cost creep and disputes.
Yongzhu Casting RFQ checklist for EV aluminum die casting parts
If you want a quote that matches real performance, send this upfront. It prevents the most common EV RFQ mistakes: unclear sealing targets, missing datum strategy, and “we assumed machining was included.”
RFQ table: what to include for a correct quote
| Item | What to send | Why it matters |
|---|---|---|
| Files | 2D drawing + 3D (STEP/IGES) | Avoids interpretation gaps and speeds DFM review |
| Alloy | Preferred alloy or performance target | Affects strength, machinability, corrosion behavior |
| Volume | Prototype vs SOP volume + ramp plan | Drives tool strategy and cost model |
| Sealing | IP target, leak target, sealing method | Determines process route and inspection approach |
| Critical features | Flatness zones, bores, threads, grounding points | Determines machining plan and control plan |
| Machining scope | Which surfaces are machined, datums, GD&T | Prevents “missing operations” misunderstandings |
| Surface requirements | Coating/finish target, corrosion expectation | Aligns material/finish system to environment |
| Assembly interfaces | Inserts, torque specs, gaskets, fastener class | Prevents boss cracking and pull-out issues |
| Environment | Salt exposure, coolant/oil contact, temperature | Drives coating, isolation, and design notes |
Want a recommendation instead of guessing?
Send your drawing + application environment, and we can recommend a practical route (HPDC or vacuum die casting + machining + finishing) and quote accordingly.
- For the full system map: EV components overview article
- For the safety definition: High-voltage components article
- For industry overview: /automotive/ (split into ICE vs EV sections)
FAQ
What EV parts are typically aluminum die cast instead of machined?
Most commonly: housings, covers, enclosures, brackets, manifold blocks, and structural battery enclosure parts—especially where function integration and repeatability matter more than pure “block machining.”
Do inverter housings usually need to be leak-tight?
Not always. Some programs require strict sealing (IP targets), while others only require splash protection. The key is to define the environment and sealing intent—water spray, immersion, coolant exposure, or dust—so the design and inspection plan matches the real requirement.
What’s the difference between HPDC and vacuum die casting for EV housings?
HPDC is widely used for many housings and structural parts. Vacuum die casting is often selected when you need lower gas porosity risk, especially for sealed parts or parts with more demanding integrity expectations. The choice depends on sealing targets, geometry, and cost trade-offs.
How do teams reduce porosity risk in sealed EV housings?
They combine process stability (temperature, shot profile), tooling features (venting/overflow strategy), and inspection discipline aligned with the sealing surfaces. The biggest improvement usually comes from treating sealing zones as functional interfaces, not cosmetic surfaces.
What should I include in an RFQ for EV aluminum die castings?
At minimum: 2D + 3D files, alloy preference, annual volume, sealing or IP targets, critical GD&T/datum scheme, machining scope, surface/coating requirements, and environment details. Missing any of these often leads to price changes or performance mismatches later.
