AIS 156 Battery Safety: What To Demand Before You Sign The PO

If you specify electric vehicles for a fleet — or run the depot that takes delivery of them — AIS 156 will show up in almost every supplier deck you read this year, usually as one reassuring line item near the back. It is worth being precise about what that line buys you.

AIS 156 is a type-approval standard. It sets battery safety requirements that a vehicle model must demonstrate to a testing agency before it can be approved for sale. It is not a certificate of condition for the pack sitting inside the vehicle that reaches your depot eighteen months later, and it was never designed to be. That gap is where a fleet buyer’s real risk lives. No fleet can re-test a battery, so your entire leverage is what you make the supplier commit to in writing before the purchase order leaves your desk.

What AIS 156 Covers — And Which Of Your Vehicles It Does Not

Start with the part most procurement decks get wrong. AIS 156 does not apply to every electric vehicle in India. In a written reply to the Lok Sabha in February 2026, the Ministry of Heavy Industries set out the split plainly: AIS 156 prescribes requirements for L-category vehicles — a motor vehicle with less than four wheels, plus quadricycles — while AIS 038 (Rev 2) covers M category, four wheels and up carrying passengers, and N category, four wheels and up carrying goods.

Translated into a depot: your e-rickshaws, e-autos and electric cargo three-wheelers are bought against AIS 156. Your electric vans, trucks and buses are bought against AIS 038 (Rev 2). A mixed fleet is buying against two standards at once, and a supplier who answers an AIS 156 question about a 2-tonne electric van is either being loose with language or has not read the certificate.

Both documents were amended by the same instrument. MoRTH notified S.O. 4567(E) on 28 September 2022 to prescribe technical requirements for traction batteries across L, M and N categories, applicable from 1 December 2022, with a second tranche of clauses taking effect on 31 March 2023. The amendment followed the 2022 fire incidents and the expert committee MoRTH convened with DRDO, IISc Bengaluru and NSTL Visakhapatnam.

Type approval tests a model, not your pack

A type approval is granted against a representative sample of a vehicle or battery type. It says this design, built this way, passed these tests. It says nothing about unit 400 off the line two years later. Government knows this, which is why a separate mechanism exists: MoRTH notified Conformity of Production requirements for all categories of electric vehicles — including quadricycles, e-rickshaws, two-wheelers and four-wheelers — through G.S.R. 888(E) on 19 December 2022. COP is the ongoing check that series production still matches the approved type. If you only ever ask about AIS 156, you are asking about the sample and ignoring the mechanism that covers the vehicle you are actually buying. Fleets that have worked through AIS 140 compliance for permit vehicles will recognise the pattern: the obligation sits with the model and the manufacturer, and it is enforced a long way from your depot.

What AIS 156 Promises: Time, Not The Absence Of Fire

The design intent behind the battery safety clauses is easy to misread. The standard does not promise a pack that cannot fail. It requires that a single cell entering thermal runaway must not cascade into fire or explosion of the whole pack, and that the system detects a thermal event early enough to raise an audible and visible warning. The objective is margin — enough time for people to get clear and for someone to act.

Around that sit the protections the Ministry of Heavy Industries listed in a December 2025 Rajya Sabha answer: EV prototypes and components are tested for over-charge and over-discharge protection, over-current and short-circuit protection, over-temperature protection, voltage cut-off, and the battery management system itself.

The field data suggests the approach is working. MoRTH’s eDAR portal, which has carried a dedicated field for electric vehicles since November 2022, recorded 23,865 accidents involving EVs across 2023, 2024 and 2025. Of those, 26 involved fire — 8 in 2023, 9 in 2024 and 9 in 2025. Accidents nearly doubled over the three years as the parc grew; the fire count did not move.

A warning only works if someone is there to hear it

That is the operational catch. Twenty-six incidents nationally is a small number, but a fleet’s exposure is not distributed like the national one — your packs sit in one yard, in rows, charging overnight, usually unattended. A requirement written to give a rider seconds to dismount is being relied on, in a depot, by nobody. Whether that warning reaches a person is a question the standard does not answer and you have to.

What To Demand From An AIS 156 Supplier, In Writing

Four documents turn a supplier conversation from a claim into a commitment. Ask for all four at RFQ stage, not after the purchase order.

Ask for this, by name	What a vague answer is telling you
The type approval certificate for the exact variant you are buying — naming the standard (AIS 156 or AIS 038 Rev 2), its amendment level, and the vehicle or battery type it was issued against	The approval may belong to a sibling variant with a different pack, motor or gross weight. You would find out during a claim.
Evidence of the Conformity of Production arrangement under G.S.R. 888(E)	Nobody is demonstrating that unit 400 still matches the unit that was tested.
Pack serial numbers mapped to chassis numbers at handover, with the cell-level test reports behind them — BIS publishes IS 16893 Part 2 and Part 3 for lithium-ion cells used to propel electric road vehicles	Your warranty and insurance position rests on a paper trail you do not hold and cannot reconstruct.
The written behaviour of the thermal warning — what it annunciates, where, whether it logs the event, and whether it is exposed on the telematics feed	You cannot design a depot response around a warning whose behaviour nobody will describe.

Four asks that cost nothing at RFQ stage and are close to unobtainable after delivery.

The amendment level matters more than it looks, and here the honest position is worth stating. The most recent change to AIS 156 that the Government has described in a press release or a parliamentary answer is still the one notified in September 2022. ARAI’s own consolidated document is titled as carrying amendments 1 to 4, the fourth dated December 2023 — but on the day this was written that file returned a 404, and ARAI’s published-standards listing loads through an interface that returns nothing to a non-browser client. So assume the standard has moved since 2022, do not assume you know how far, and make the supplier state the amendment level on the certificate rather than inferring it from a brochure.

A supplier who can produce a marketing claim but not a certificate naming your variant is selling you a product family, not your vehicle. That is not always bad faith — on smaller three-wheeler platforms the paperwork genuinely sits with a battery vendor two steps down the chain. But it tells you exactly where your risk is, and it is the difference between a warranty conversation you can win and one you cannot.

The Depot Consequences You Actually Own

Everything above is procurement. This is the part that outlives the purchase order, and it is short enough to write on one page.

Give yourself somewhere to put a suspect vehicle. One marked bay, outdoors, clear of the charging line and the building, with space around it. A vehicle that has taken an underbody impact, been submerged, or thrown a thermal or BMS warning goes there and is not charged until it has been inspected — and stays watched for a day or two, because a damaged cell does not always fail immediately.

Decide who the warning reaches. A temperature or pack fault that annunciates only on a rider’s display at 2 a.m. in a locked yard has warned nobody. Route pack and temperature faults into your fleet alerts so they land with a named person on shift, with an escalation path if that person does not acknowledge.

Keep the pack-to-chassis map current. Packs get swapped; certificates and warranties follow the pack serial, not the chassis. Holding that mapping in your EV vehicle tracking records — rather than in a supplier’s email thread — is what makes a warranty or insurance claim provable later. In-service pack condition is a separate discipline with its own thresholds, and our guide to battery state of health covers where those sit.

Then rehearse it. Isolate, evacuate, call, do not move the vehicle, do not open the pack. A procedure nobody has practised is a document, not a procedure.

AIS 156 is a floor, and a real one — the fire numbers say so. But it certifies a design to a testing agency, and you are buying a specific vehicle from a specific supplier on a specific day. The distance between those two facts is closed by four documents and one depot procedure, and all of them are cheaper to obtain before you sign than after something goes wrong. A fleet operating system like YoMobility gives the resulting records somewhere to live, but the demand has to come from procurement first.

Sources: PIB — Ministry of Heavy Industries, Lok Sabha reply on EV fire incidents (10 Feb 2026) | PIB — MoRTH on the phased AIS-156 / AIS-038 (Rev 2) amendment (27 Sep 2022) | Ministry of Heavy Industries — Lok Sabha USQ 2670 (5 Aug 2025) | Ministry of Heavy Industries — Rajya Sabha USQ 1528 (12 Dec 2025) | ARAI — Automotive Industry Standards Committee