SoH, UID & Supply Chain: Technical Passport Requirements

Beyond high-level compliance timelines, the EU battery passport hinges on technical details that engineering and supply chain teams must get right: State of Health (SoH) battery tracking, globally unique identifiers, recycled material thresholds, and coordinated data flows from cell suppliers to OEM passport registries.

Battery Unique Identifier (UID) Requirements

Every passport begins with a battery unique identifier (UID) that is:

• Globally unique — no two batteries in the EU market share the same UID
• Immutable — assigned once at manufacturing and never reassigned
• Machine-readable — encoded in QR code and human-readable text on the label
• Persistent — valid for the entire battery lifecycle including second life and recycling

Implementing acts define format conventions; PassCell's global serial registry allocates collision-free UIDs with category prefixes (e.g., EV, LMT, IND) for operational clarity.

State of Health (SoH) Battery Tracking

State of Health battery tracking is a dynamic passport requirement — unlike static composition data, SoH must be updated as the battery ages. Key principles:

• Initial SoH (typically 100% or calibrated baseline) recorded at manufacturing
• Periodic updates from BMS telemetry during in-service operation
• SoH expressed as percentage of original rated capacity
• Restricted access — full SoH history may be visible only to authorized recyclers, fleet operators, or market surveillance authorities

Passport platforms must accept API-driven SoH updates without requiring re-printing of QR labels — the UID-linked registry record is updated in place.

Recycled Content Thresholds: Cobalt, Lithium, Nickel

The regulation establishes phased recycled content thresholds for cobalt, lithium, and nickel in active materials of EV batteries:

Material	2031 minimum	2036 minimum
Cobalt	16%	26%
Lithium	6%	12%
Nickel	6%	15%

Passport data must declare actual recycled content percentages and verification methodology. Even before thresholds become legally binding, downstream buyers and auditors increasingly request this data in procurement contracts.

Supply Chain Due Diligence: Regulation (EU) 2025/1561

Supply chain due diligence under Regulation (EU) 2025/1561 requires economic operators to identify, prevent, and mitigate social and environmental risks linked to critical raw material sourcing. Passport-relevant outputs include:

• Published due diligence policy summary (public passport field)
• Third-party audit reports (restricted access)
• Supply chain risk assessment results for cobalt, lithium, nickel, and natural graphite
• Evidence of grievance mechanisms and remediation actions

Due diligence obligations apply from August 2025 — before the passport mandate itself — making this an immediate priority for compliance teams.

Upstream Supplier Data Coordination

Upstream supplier data coordination for battery passports is the operational bottleneck most manufacturers underestimate. Cell suppliers hold composition, test, and manufacturing data that pack assemblers and OEMs cannot fabricate.

Best practices for supplier coordination:

1. Standardize data templates — provide suppliers with Annex XIII field mappings, not open-ended data requests
2. Contractual clauses — require structured data delivery (JSON/CSV) with each shipment batch
3. Verification gates — block passport publication until required supplier fields are validated
4. Version control — track supplier data revisions when cell chemistry or sourcing changes mid-program

Cell Supplier Data Sharing

Cell supplier data sharing for battery passports raises IP and competitive sensitivity concerns. Common approaches:

• Suppliers provide aggregated composition data without revealing proprietary formulations
• Restricted passport fields visible only to authorized auditors, not competitors
• Platform-enforced access controls separate public, operator, and authority views
• Batch-level certificates rather than continuous real-time supplier system integration (for smaller suppliers)

Building a Technical Foundation

Technical compliance is not a one-time data entry exercise. It requires:

• A UID registry integrated with production serial numbers
• API endpoints for SoH lifecycle updates from BMS or telematics systems
• Supplier data ingestion pipelines with validation rules
• Role-based access control aligned with Annex XIII visibility tiers

PassCell implements all four layers in a single platform — see our compliance software guide for integration details.