UNECE R100, also written ECE R100 or UN Regulation No. 100, is the UN type-approval regulation for electrical safety in road vehicles with an electric power train. It applies to M and N category vehicles above 25 km/h and comes in two parts. Part I approves the vehicle: shock protection, isolation resistance, behaviour after water exposure, driver warnings, prevention of unintended movement. Part II approves the battery system on its own, through vibration, thermal cycling, crash-level shock and crush, external fire and a set of electrical abuse tests. Different applicants file each one. The vehicle manufacturer files Part I, the battery manufacturer files Part II. That split is what matters commercially: fit a battery that already holds a Part II approval, install it as its manufacturer specifies, and your vehicle approval does not put the battery through those tests again. You still need Part I for the rest of the electric power train. IONETIC does R100 approval on every battery system as standard programme scope.
What R100 is, in plain terms
R100 governs the electrical safety of road vehicles with an electric power train. Scope is categories M and N with a maximum design speed above 25 km/h, excluding vehicles permanently connected to the grid.
It comes in two parts. Part I approves the vehicle. Part II approves the battery system, which the regulation calls a rechargeable electrical energy storage system, or REESS.
Neither part is self-certified. A national Type Approval Authority grants the approval and a designated Technical Service runs the tests. No battery supplier issues its own R100 approval, whatever a data sheet implies.
Two exclusions save time early. R100 does not cover post-crash electrical safety, which sits in the crash regulations. And Part II ignores batteries whose job is starting, lighting or auxiliaries, so your 12 V system is out and your traction pack is in.
Approving the pack means the vehicle does not approve it again
This is the structural point people miss, and it decides how much of your programme is spent on batteries instead of on vehicles.
The two approvals have different applicants. The application for Part I is submitted by the vehicle manufacturer. The application for Part II is submitted by the battery manufacturer. Separate approvals, separate paperwork, separate holders.
When a vehicle fitted with a battery goes for its Part I approval, one of two things has to be true. Either the battery already holds a Part II approval and is installed exactly as its manufacturer specifies, in line with the description recorded on the approval documents. Or the battery, together with the surrounding vehicle components, systems and structure, has to be shown to meet the Part II requirements as part of your own vehicle approval.
Route one turns the pack into a component you specify, mark and fit. The abuse testing is finished, closed and evidenced before your vehicle approval starts. Route two turns your vehicle programme into a battery abuse-testing programme. At a few hundred vehicles a year, that difference decides whether your team spends a year on the vehicle or a year on a shaker table.
Be precise about what route one does not do. It does not remove your vehicle approval. You still need Part I, and Part I is real work: protection against electric shock, isolation resistance, behaviour after water exposure, warnings to the driver, prevention of unintended movement. What a Part II approval takes out of that scope is the battery. The battery arrives already approved.
If you are buying packs, ask which route your supplier is proposing, and get the answer in writing.
What the tests are actually for
Part II is not a random collection of abuse. Each test stands in for something the pack will meet in the real world.
Vibration and thermal cycling stand in for the pack's life. Years of road input and every climate you sell into, compressed into a few days. What fails here is rarely the cells. It is joints, bonded interfaces, busbar terminations and anything whose stiffness moves with temperature.
Mechanical shock and mechanical integrity stand in for a crash. Shock applies the inertial loads of an impact, integrity crushes the pack between plates. Enclosure structure and cell retention are on trial, not the chemistry.
Fire resistance stands in for a vehicle fire that starts outside the pack. The point of it is escape time for the occupants.
The electrical tests stand in for things going wrong. Short the terminals, charge past the limit, discharge past the limit, run it hot with the cooling defeated, push overcurrent during DC charging. Every one of them is really a test of whether your protection acts before the chemistry does. These are BMS and safety-architecture tests wearing a battery costume.
Documentation covers what a rig cannot show. Warnings for failure of the safety controls, warnings for a thermal event and thermal propagation are met largely by system diagrams, thresholds and control logic handed to the Technical Service. Thin BMS documentation costs you here, not on the shaker.
One acceptance criterion is worth knowing before you draw anything. Under the 02 series, a test was passed if there was no electrolyte leakage, no rupture, no fire and no explosion. The 03 series inserted venting into that list, for any battery other than an open-type traction battery, across vibration, thermal cycling, external short circuit, overcharge, over-discharge, over-temperature and the new overcurrent test (paragraphs 6.2.2.1, 6.3.2.1 and 6.6.2.1 to 6.10.2.1). A design that survived by venting safely used to pass. It does not now.
Change the design and you go back to the authority
Every modification to an approved vehicle or battery type has to be notified to the Type Approval Authority that granted the approval. The Authority can revise the approval, extend it, or decide that a new type approval is needed.
An extension can mean going back to the test house. That is the real cost of design churn late in a programme, and it is not the engineering change itself. It is the certification consequence: new samples, a new booking at a test house that keeps no slot free for you, new documentation, a launch date that moves.
The cheapest approval is the one you get right the first time.
Where the approval travels
UN type approvals are recognised across the countries party to the 1958 Agreement, which is why an approved pack travels well across the UK, Europe and much of Asia.
The United States is the exception that catches programmes out. It does not operate UN type approval. Electrical safety there sits in the Federal Motor Vehicle Safety Standards and compliance is by self-certification, so an R100 approval is not a route to market in the US.
R100 is also a road vehicle regulation. Vessels and off-highway machines sit outside its scope and follow other regimes.
Why an already-engineered architecture changes your odds
Certification effort does not scale with volume. A programme building 500 vehicles carries broadly the same test set, the same documentation and the same destructive samples as one building 50,000. It just has far fewer units to spread the cost over, and far less tolerance for doing it twice.
That is where an architecture and platform approach earns its money, and it is worth being precise about how. It does not exempt your pack. The tests still run on your hardware. What it changes is what you can reasonably expect from them.
If the interfaces, the cell-to-cooling-plate design, the enclosure structure and the safety architecture have already been engineered and already been through R100, your pack is a configuration of a known thing. You enter the campaign expecting to pass. A clean-sheet pack enters hoping to. Those are different programmes. One you can plan a launch around.
It changes the hardware too. Approval testing destroys what you feed it, and every test article costs whatever it cost to build. Because our packs are configurations of an architecture that already exists, prototype build cost is lower, and the same destructive campaign costs less. Sample maturity moves as well. Because we run an architecture and platform approach, even our early prototypes can be at B+ sample maturity. A typical A sample is a first attempt at packaging, thermal path and structure, built to learn from rather than to certify on. Ours starts from structure, cooling and safety design that already exist, so the hardware is representative earlier and can go on a rig sooner.
How we handle it
We do R100 approval on all battery systems as a standard part of our development programmes. UN 38.3, the transport test series you need before a pack can legally leave your building, is handled the same way.
Three things follow from that. You start with confidence of passing, because the pack is a configuration of an architecture that has already been engineered and already been through approval. You spend less on the hardware you destroy, because the prototypes are cheaper to build. And you deal with one partner for design, build, test and approval, instead of coordinating a design house, a fabricator, a test house and a homologation consultant yourself.
If you know you need R100 and want to see what the scope looks like for your vehicle category and target markets, get in touch and we will set it out in writing.
