This document outlines a set of rigorous tests aimed at helping battery manufacturers evaluate and classify their products based on safety and design excellence. These tests go beyond binary pass/fail standards to enable continuous improvement strategies across the full battery lifecycle.
Why Standard Tests Fall Short
Traditional certification standards such as AIS-048 and AIS-156 include tests like nail penetration at full charge — useful stress indicators, but inherently limited as holistic quality guides. The same battery can pass a standard test under controlled lab conditions and fail when manufacturing processes change by even a small margin.
⚠ Standard tests provide valuable reference points, but should not be the sole basis for evaluating overall battery design quality. Binary pass/fail outcomes reveal little about how close a design is to failure.
Our evaluation framework supplements regulatory minimums with a continuous scoring model that surfaces design weaknesses before they become field failures. This enables systematic improvement rather than one-shot qualification testing.
Core Test Categories
We group our evaluation suite into four clusters, each targeting a distinct failure mode observed across Li-ion battery packs deployed in Indian operating conditions.
Thermal Stability
Forced short-circuit, overcharge, and accelerating rate calorimetry tests to map thermal runaway thresholds.
Mechanical Integrity
Crush, drop, vibration (IEC 62133), and penetration tests simulating real-world logistics and deployment stress.
Electrical Performance
Capacity retention across temperature bands, internal resistance progression, and cycle life benchmarking.
Environmental Durability
IP-class ingress testing, humidity cycling, and dust exposure protocols calibrated for Indian climate conditions.
The Rating Framework
Unlike binary certification, our framework assigns a continuous score across five design dimensions. Each score is derived from multiple sub-tests, weighted by field-failure correlation data from our deployed fleet of 200+ units.
| Dimension | Sub-Tests | Score Range | Method |
|---|---|---|---|
| TD — Thermal Design | Calorimetry, vent gas analysis, cell propagation | 0 – 100 | Continuous |
| ME — Mechanical Enc. | Crush load, drop height, IP rating | 0 – 100 | Continuous |
| EP — Electrical Protection | BMS response time, overcurrent cutoff, balancing accuracy | 0 – 100 | Continuous |
| CL — Cycle Life | Capacity at 500 / 1000 / 2500 cycles | 0 – 100 | Continuous |
| EV — Environmental | Humidity, dust, thermal range | 0 – 100 | Continuous |
| Overall TEC Safety Index | Weighted composite | A+ / A / B / C / D | Grade |
Sample: FlexiPack 2.7 kWh — TEC Safety Index
"The goal isn't to pass a test. It's to understand exactly how far from failure your design lives — and to move that margin further away with every iteration."
Identifying Design Flaws Early
Cell Matching & Balancing
Mismatched internal resistance between cells in a pack is one of the most common sources of premature capacity fade and thermal events. Our incoming inspection protocol measures cell impedance spectroscopy at 1 kHz and groups cells within a ±2 mΩ tolerance window before assembly.
BMS Latency Under Fault Conditions
A battery management system that responds to an overcurrent event in 12 ms is meaningfully different from one that responds in 180 ms — even if both technically "pass" the same standard. We measure and publish BMS response latency as a first-class design metric.
✓ TEC FlexiPack BMS cutoff latency: 8 ms median, 14 ms 99th percentile — consistently below the 50 ms industry threshold for Li-ion fault isolation.
Thermal Runaway Propagation
In a multi-cell pack, a single cell event should not cascade. Our cell-to-cell propagation testing uses intentional single-cell thermal runaway initiation to measure whether the enclosure design and vent architecture contain the event within 60 seconds. Packs that fail this test are not shipped regardless of AIS compliance.
India-Specific Calibration
Generic international standards are calibrated to temperate climate assumptions. Indian deployments face conditions that stress batteries in ways that standard tests underrepresent: ambient temperatures routinely reaching 48°C in Rajasthan, high-humidity coastal environments in Chennai, and persistent voltage fluctuations from grid instability across the country.
Our environmental test protocols extend standard ranges to:
| Parameter | IEC Standard | TEC India Profile |
|---|---|---|
| Max ambient temp | 40°C | 52°C (soak + cycling) |
| Humidity | 85% RH | 95% RH, 7-day exposure |
| Dust ingress | IP5X | IP6X + vibration simultaneous |
| Charge voltage variance | ±5% | ±15% (grid fluctuation sim.) |
| Cycle life benchmark | 500 cycles | 2,500 cycles at 1C |
Using This Framework
This handbook is designed to be a living reference. As we gather data from FlexiTwin digital twins across our deployed fleet, test weightings are updated quarterly to reflect real-world failure distributions rather than theoretical models.
Battery manufacturers and OEM partners are encouraged to use the TEC Safety Index as a design target, not just a final qualification hurdle. The most reliable packs we've seen are those designed with continuous scoring in mind from day one — not retrofitted to pass tests at the end of development.
✓ For access to the full test protocol specifications and scoring algorithm, contact safety@energycompany.in or connect via LinkedIn.