Performance and durability: the group you can mostly answer yourself.
Amid the difficulty of carbon footprint and recycled content, it is worth being clear about the part of the battery passport that is genuinely within your control. Performance and durability together account for twenty-seven attributes — rated capacity, voltage envelope, power, internal resistance, expected lifetime and the parameters describing how the battery ages — and most of them already exist in your own test reports and specification sheets. This group is where a readiness project makes fast, visible progress.
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In one line: performance and durability are the twenty-seven attributes you can largely answer from testing you have already done — which makes them the right place to start a passport project, because progress here buys time for the upstream data that is slow.
What sits in these two groups
The performance group covers the electrical envelope: rated capacity, nominal and minimum and maximum voltage, rated and maximum power, internal resistance, temperature range and the conditions under which those values were measured. The durability group covers expected lifetime and the ageing characteristics — the parameters that let someone judge how the battery behaves over its service life rather than on day one.
Exact keys, datatypes and access tiers are in the field list. What matters at planning stage is that these attributes are measured values with stated conditions, not marketing figures. A capacity claim without its measurement conditions is not a usable answer.
Why "we already have this" is usually half true
Manufacturers almost always hold these numbers. What they frequently do not hold is the numbers in a form the passport can carry:
Conditions are missing. A datasheet says 15 Ah. The passport wants to know at what rate, at what temperature, to what cut-off.
Values live in PDFs. Test reports are documents; the passport needs structured, typed values that a machine can read and a regulator can query.
Model-level versus item-level. Some values legitimately describe the model. Others are expected to reflect the individual battery, and the passport is issued per battery.
Units and precision drift between the engineering team, the datasheet and the certificate — and inconsistency across those three is exactly what an auditor notices.
Where this group meets the dynamic data problem
Performance and durability describe the battery as manufactured. Immediately adjacent sits the telemetry group — state of health, cycle counts, energy throughput, time spent in extreme temperatures — which describes the battery as used, and which cannot be filled in at launch because the values do not exist yet.
The distinction matters commercially as well as technically. Rated capacity is a specification; remaining capacity is what a second-life buyer or an insurer actually prices. A passport that carries a credible durability declaration at manufacture and a maintained health record afterwards is worth considerably more than one that stops at the datasheet. That is the difference between a compliance record and an asset record.
How to work this group efficiently
Start here, not with carbon footprint. You can close most of these attributes without asking anyone outside your own company, which builds momentum and shows the project is real.
Extract from existing test reports rather than re-testing. The measurements were already taken; the work is structuring them.
Record measurement conditions with every value. A number without conditions will come back as a question later.
Decide model-level versus item-level early, because it determines whether the value is set once or captured per unit in production.
Plan the telemetry path before go-live — retrofitting a health record onto batteries already in the field is materially harder than designing it in.
Frequently asked questions
Do performance values have to be per individual battery or per model?
It varies by attribute. Some describe the model and are set once; others are expected to reflect the individual battery. Because the passport itself is issued per battery, the practical question is which values your production process captures per unit and which it inherits from the model.
Can we reuse the numbers from our existing test reports?
Usually yes, and you should — the measurements already exist. The work is structuring them into typed values with their measurement conditions attached, rather than leaving them inside a PDF that a machine cannot read.
What is the difference between the durability fields and the state-of-health fields?
Durability describes the battery as manufactured: expected lifetime and how it is designed to age. State of health and the other telemetry attributes describe the battery as used, and only come into existence once it is in service. The first can be completed before launch; the second cannot.
Are these fields publicly visible?
Access varies by attribute across the tiers set out in Annex XIII — some performance information is publicly accessible, other detail is restricted to those with a legitimate interest, and conformity test results are limited to notified bodies and market-surveillance authorities. The field list marks the tier for each one.