Battery Management Systems (BMS), Onboard Chargers (OBC), and charging station control boards—PCB assembly requirements for these three core new energy vehicle systems differ completely.
BMS handles hundreds of amperes of current, onboard chargers contain high-voltage high-power circuits, and charging station control boards operate long-term in outdoor environments.
Without relevant experience, manufacturers may encounter problems: solder joints unable to handle high current leading to overheating, insufficient high-voltage circuit creepage distances creating safety hazards, inadequate outdoor equipment protection causing frequent failures.
This article explains manufacturing differences among these three product types and how to determine whether EMS suppliers possess appropriate capabilities.
BMS Battery Management Systems: Why High-Current Handling Capability Matters
Real Issue: Can Solder Joints Handle Hundreds of Amperes?
BMS monitors and controls battery pack charging and discharging. Power battery operating currents typically range from tens to hundreds of amperes, with peak currents potentially higher.
If the PCB copper foil is too thin or the solder joint quality is poor, high current passage generates excessive heat. Long-term operation may cause:
- Excessive solder joint temperatures, gradual aging, or even desoldering
- PCB overheating and warping, affecting electrical connections
- Inaccurate temperature detection, impacting battery protection functions
This is why BMS PCBs typically use 3-6oz copper thickness (standard PCBs use 1-2oz). Thicker copper foil better carries high currents while reducing heat generation.
Manufacturing Capability Requirements
When inquiring with EMS suppliers, ask:
- Can you manufacture and assemble 3oz+ heavy copper PCBs?
- How are high-current solder joints processed? Do you have specialized processes?
- How do you validate solder joint reliability under high current?
Venture Electronics supports 3-6oz heavy copper PCB assembly, equipped with X-Ray inspection equipment to verify high-current solder joint quality.
Our nitrogen vacuum reflow soldering process controls solder joint void rates to 1-2%, improving high-current solder joint thermal conductivity and mechanical strength.
Related reading: Electric Vehicle PCB Assembly: EMS Manufacturer Selection Checklist
Onboard Chargers (OBC): Heat Dissipation Challenges from High-Power Conversion
Real Issue: How to Handle Heat Generated by Power Devices?
Onboard charger power ranges from 3.3kW to 22kW. High-power conversion means internal power semiconductors (IGBT, MOSFET, SiC, and GaN devices
) generate substantial heat.
Heat dissipation design or assembly process issues may cause:
- Power device overheating and derating, failing to achieve design charging power
- Excessive temperatures accelerating device aging and shortening lifespan
- Extreme cases triggering over-temperature protection, causing charging interruptions
Onboard charger PCBs typically require metal core PCBs (MCPCB) or heavy copper PCBs, with thermal pads or heat sinks beneath power devices.
Manufacturing Capability Requirements
When inquiring with EMS suppliers, ask:
- Do you have metal core board or heavy copper board assembly experience?
- How are power device heat dissipation structures installed?
- Can you provide thermal simulation or actual temperature measurement validation?
Venture Electronics provides metal core PCB assembly services, equipped with thermal imaging inspection equipment to verify power device heat dissipation effectiveness.
Related reading: PCB Assembly Extreme Temperature Reliability (-55°C to 125°C)
Charging Station Control Boards: Outdoor Environment Protection Requirements
Real Issue: How Outdoor Equipment Prevents Water, Dust, and Corrosion?
Charging stations are typically installed in outdoor parking lots, exposed to natural environments year-round. Control boards face:
- Rainwater penetration risks
- Dust and pollutant accumulation
- Temperature extremes (summer heat, winter cold)
- Coastal area salt spray corrosion
Without proper PCB protection, problems may include:
- Moisture causing circuit shorts or leakage
- Dust accumulation causing poor heat dissipation
- Salt spray corroding solder joints and copper foil
Charging station control boards typically require conformal coating or electronic potting treatment, achieving IP65 or IP67 protection ratings.
Manufacturing Capability Requirements
When inquiring with EMS suppliers, ask:
- Do you provide conformal coating or potting services?
- Can protection ratings reach IP65 or IP67?
- Do you have outdoor equipment manufacturing case studies?
Venture Electronics provides PCB conformal coating and electronic potting services, supporting IP65/IP67 grade protection treatment.
Among our communication industry customers, many outdoor base station equipment have similar protection requirements.
Common Requirement Across All Three Products: Automotive-Grade Temperature Range
Whether BMS, OBC, or charging stations, all require normal operation within -40°C to 85°C temperature ranges (some applications extend to -40°C to 125°C).
This requires:
- Component selection at automotive-grade (such as AEC-Q100 and AEC-Q200 qualified components)
- PCB substrates using high-Tg materials
- Soldering processes capable of withstanding temperature cycling tests
Venture Electronics supports automotive-grade temperature range component procurement and assembly, providing temperature cycling test validation.
How to Determine Whether EMS Suppliers Suit New Energy Vehicle Projects
When selecting EMS manufacturers, evaluate their actual capabilities through these questions:
Question 1: Do you have new energy vehicle-related manufacturing experience?
Ask specifically: Have you worked on BMS, OBC, or charging station assemblies?
Because these three product types have distinct manufacturing focuses, suppliers with relevant experience will better understand your actual requirements.
Question 2: Can you support heavy copper PCB and high-power assembly?
Both BMS and OBC involve high current or high power, requiring specialized PCB and assembly processes.
Ask suppliers about maximum supported copper thickness and power device heat dissipation solutions.
Question 3: What are your protection treatment capabilities?
Outdoor equipment like charging stations requires IP65/IP67 protection.
Ask suppliers whether they provide conformal coating and potting services, along with actual case studies.
Question 4: What are your testing and validation capabilities?
New energy vehicle products typically require temperature cycling testing, high-temperature aging, and functional testing.
Ask suppliers about testing equipment and validation processes.
Venture Electronics provides complete EMS services for new energy vehicle customers, from component procurement to assembly, testing, and protection treatment.
Among our customers, the new energy industry accounts for 10%, with accumulated manufacturing experience in BMS and charging stations.
Learn more: PCBA for EV
Select Manufacturing Partners with Real Experience
BMS, onboard chargers, charging stations—each product type presents unique manufacturing challenges.
Selecting EMS suppliers with relevant experience avoids many potential issues.
If you’re seeking PCB assembly partners for new energy vehicle projects, contact Venture Electronics’ technical team.
We can explain process solutions and provide project feasibility assessments based on your specific product type and application requirements.
