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Decoding Li-Po Battery Model Numbers and Labeling Standards: A Comprehensive Guide

In the intricate world of electronics manufacturing, the battery is more than just a power source; it is a critical component defined by precise physical dimensions and chemical capabilities. Yet, for many procurement managers and engineers, picking up a Lithium Polymer (Li-Po) battery can feel like reading a secret code. Strings of numbers like “103040” or “802540,” accompanied by logos like CE, UN38.3, and varying C-rates, cover the silver foil pouch.

Misinterpreting these labels is not a trivial error. In the battery world, a few millimeters difference in size can mean a battery that doesn’t fit the device cavity. A misunderstood voltage code can lead to fried circuits. Worse, overlooking missing certification marks can result in customs seizures or safety hazards.

At Hanery, transparency is part of our manufacturing philosophy. As a leading Chinese manufacturer specializing in polymer lithium batteries, 18650 packs, and Lithium Iron Phosphate (LiFePO4) solutions, we adhere to strict international labeling standards. We believe that an educated client is a safe client. Whether you are sourcing batteries for a new medical wearable or a fleet of industrial drones, understanding the language of the label is your first line of defense against low-quality counterfeits and integration failures.

This comprehensive guide will act as your decoder ring. We will break down the geometry-based model numbering system, explain the regulatory symbols that matter, and teach you how to spot a fake specification sheet.

103040, 802540 Format Explained: The Geometry Code

Unlike cylindrical batteries (e.g., 18650), which have standardized sizes, Li-Po pouch cells can be manufactured in virtually any dimension. To manage this variety, the industry adopted a 6-digit (or sometimes 5-digit) model number that describes the cell’s physical size.

The standard format is TTWWLL (Thickness – Width – Length).

Breaking Down the Code

Let’s analyze a common model number: 503040.

50 (Thickness): 5.0mm. The first two digits represent thickness in tenths of a millimeter.
30 (Width): 30mm. The middle two digits represent the width in millimeters.
40 (Length): 40mm. The final two digits represent the length in millimeters.

Examples:

103450: 10.0mm thick x 34mm wide x 50mm long. (Common in industrial devices).
802540: 8.0mm thick x 25mm wide x 40mm long. (Common in small wearables).
603048: 6.0mm thick x 30mm wide x 48mm long.

Hanery Insight: If a model number starts with “05,” such as 053040, it typically means 0.5mm thickness. Always confirm with the datasheet, as different manufacturers may have slight variations in how they denote sub-millimeter thickness.

Size Rules (mm-based) and Tolerances

While the model number gives you the nominal size, the actual size often varies slightly due to the flexible nature of the pouch and the sealing process.

The "Max" vs. "Nominal" Trap

Nominal Dimensions: The numbers printed on the label (e.g., 503040).
Max Dimensions: The actual physical limit, including the folded sealant edge (the “terrace”) and the swelling that occurs over the battery’s life.

Design Tolerances

When designing a battery compartment, you should never make it exactly 30mm wide for a “30mm” wide battery.

Width: Add +1mm for sealant folds.
Length: Add +2mm for the tab exit area.
Thickness: Add +10% for natural swelling. A 5.0mm battery can expand to 5.5mm after 500 cycles due to gas generation.

Hanery Engineering Rule: We always recommend our OEM clients leave a “breathing room” margin in their device housing. A tight fit can lead to mechanical pressure on the cell, causing internal shorts.

Voltage Codes: Reading the Power Potential

Voltage is the electrical pressure of the battery. The label will typically list the Nominal Voltage, but it is vital to understand what that implies for the charging and cutoff voltages.

Standard Li-Po (3.7V)

Label: 3.7V
Meaning: Standard Lithium Cobalt Oxide (LCO) or NMC chemistry.
Full Charge: 4.20V
Empty: 3.00V

High Voltage Li-Po (3.8V / 3.85V)

Label: 3.8V or 3.85V (often marked as LiHV)
Meaning: High-Voltage chemistry designed for higher energy density.
Full Charge: 4.35V or 4.40V
Risk: Charging a standard 3.7V battery to 4.35V will cause fire. Always check the label carefully.

Series and Parallel Codes (S/P)

On multi-cell packs, you will see codes like 3S1P or 2S2P.
- S (Series): Increases voltage. 3S = 3 x 3.7V = 11.1V.
- P (Parallel): Increases capacity. 2P = 2 x Capacity.
- Example: A label reading “11.1V 5000mAh 3S1P” means three 5000mAh cells connected in a series chain.

Batch and Date Codes: Traceability

For industrial procurement, the Date Code is arguably the most important data point on the label. Batteries degrade over time, even when sitting on a shelf. You do not want to buy “new” batteries that were manufactured three years ago.

Common Formats

Manufacturers use different codes, but they generally follow a Year-Month-Day pattern.

YYMMDD: 240512 = May 12, 2024.
Alphanumeric: Some use a letter for the year (e.g., J=2024) and a letter for the month (e.g., E=May).

The QR Code Revolution

Modern Hanery batteries often feature a small Data Matrix or QR Code on the label. Scanning this code reveals:

Manufacturing date.
Electrolyte batch number.
Internal resistance grading data (Grade A/B).

Tip: If a supplier cannot tell you the date code or the manufacturing date of a batch, do not buy it. It is likely aged surplus stock.

Certification Labels: The Passport to Global Markets

If you plan to ship your device internationally, the battery label must carry specific regulatory marks. Without them, your product may be seized by customs or rejected by air freight carriers.

UN38.3: Mandatory. Indicates the battery has passed 8 safety tests (altitude, thermal shock, vibration, etc.) required for air transport. Often not printed as a logo but required on shipping docs.
CE (Conformité Européenne): Mandatory for EU. Certifies compliance with EU safety, health, and environmental requirements.
UL (Underwriters Laboratories): Critical for USA. The UL Listed mark (specifically UL 1642 or UL 2054) is the gold standard for safety in the American market.
KC (Korea Certification): Required for selling batteries in South Korea.
PSE (Japan): Required for the Japanese market.
RoHS: Certifies the battery is free of hazardous materials like lead and mercury.

Hanery Compliance: We ensure our custom packs carry the specific certifications required for your target market, printing them legibly on the label to streamline your customs clearance.

OEM vs Generic Labels: Spotting Quality

The quality of the label often reflects the quality of the cell.

The Generic "Blue/Silver" Wrap

Information: Often just lists “3.7V” and a vague capacity like “5000mAh.”
Missing: Manufacturer name, address, warnings, certification marks, and C-rates.
Risk: These are often “B-grade” cells rejected from major factories and resold. They have inconsistent performance and safety.

The OEM/Brand Label (e.g., Hanery)

Information: Full model number, exact capacity (Min/Typ), Voltage, Watt-hours, C-Rate, Manufacturer Contact Info, Warning Icons (Do not crush, trash bin), and Regulatory Marks.
Quality: The label is durable, high-contrast, and clearly printed.

Mislabeling Issues: The Capacity Lie

One of the biggest plagues in the lithium battery industry is Capacity Inflation.

The "Fire" Label

You might see a standard-sized 18650 battery labeled “9900mAh.”

The Physics: The theoretical maximum capacity for an 18650 cell using current chemistry is roughly 3500-3600mAh. Anything higher is chemically impossible.
The Pouch Equivalent: Similarly, if a small 503040 pouch cell claims 2000mAh, be suspicious. A cell of that size typically holds ~600-800mAh.

The C-Rate Exaggeration

Labels claiming “100C” or “150C” discharge rates are often marketing hyperbole. While burst rates can be high, true continuous discharge at those levels would melt the tabs of most standard packs. Always ask for the Datasheet to verify the true continuous discharge rating.

Safety Compliance Requirements: The Warning Block

A compliant Li-Po label must include a safety warning section. This is not just advice; it is a liability requirement.

Standard Warnings Include:

“Do not short circuit.”
“Do not disassemble or incinerate.”
“Do not expose to high temperatures (>60°C).”
“Use specific charger only.”

If a battery label lacks these warnings, the manufacturer is cutting corners on compliance, which suggests they may have cut corners on the cell chemistry too.

How to Verify Authenticity

You have the battery in hand. How do you know the label is telling the truth?

Weigh It

Energy has weight. A high-capacity battery contains more anode and cathode material.

Check: Weigh the questionable battery against a known genuine battery of the same size. If the new one is 20% lighter, it is a fake with low capacity.

Measure Internal Resistance (IR)

Use a specialized battery resistance tester (or a high-end charger).

Good: < 50 mΩ (depending on size).
Bad: > 100 mΩ. High resistance indicates an old or low-quality cell, regardless of what the label says about “High Power.”

Capacity Test

Use a discharger to drain the battery from 4.2V to 3.0V at a standard rate (0.2C).

Result: If a “5000mAh” battery only delivers 3000mAh, the label is fraudulent.

Label-Reading Examples

Let’s dissect two theoretical labels to apply what we’ve learned.

Label A: The Industrial Standard

Hanery
Model: 603048
Voltage: 3.7V Capacity: 900mAh / 3.33Wh
Date: 2024-11-05
Cert: CE, RoHS, UN38.3
Warning: Risk of Fire. Do not puncture.
[QR Code]

Analysis: This is a trustworthy label. It gives the Watt-hours (crucial for shipping), clear date code, and dimensions (6mm x 30mm x 48mm).

Label B: The Suspicious Generic

SUPER POWER
LIPO BATTERY
50000mAh
3.7V
[No Date Code]
[No Warnings]

Analysis: This label is a red flag. The capacity is likely exaggerated (unless the battery is the size of a brick), and the lack of manufacturer info and safety warnings makes it a liability.

Comparison Chart: Common Li-Po Model Numbers & Dimensions

Model Number	Thickness (mm)	Width (mm)	Length (mm)	Typical Capacity (mAh)	Common Use
053040	0.5	30	40	120 – 150	Smart Cards, RFID Tags
402030	4.0	20	30	150 – 200	Bluetooth Headsets
503040	5.0	30	40	500 – 600	Key fobs, Small Wearables
603048	6.0	30	48	800 – 900	IoT Sensors, GPS Trackers
802540	8.0	25	40	600 – 750	Small Drones, Toys
103450	10.0	34	50	1800 – 2000	Portable Speakers, Medical Devices

Note: Capacities are estimates and vary based on electrode density and voltage cutoff.

Frequently Asked Questions

What do the numbers 103040 mean on a battery?

They represent the physical dimensions of the cell: 10mm thick, 30mm wide, and 40mm long. Always measure with calipers (using plastic tips to avoid shorts) to verify.

Is a 3.7V battery the same as an 11.1V battery?

No. A 3.7V battery is a single cell (1S). An 11.1V battery is a pack made of three cells connected in series (3S). You cannot replace one with the other; the voltage difference would destroy your device.

Why does my battery label say 12.6V Max?

This is the Charging Voltage. For a 3S pack (11.1V nominal), the fully charged voltage is 12.6V (4.2V x 3). This helps users set their chargers correctly.

Can I use a battery with a different model number if it fits?

Yes, provided the voltage is the same. For example, replacing a 503040 (600mAh) with a slightly thicker 603040 (700mAh) is a great upgrade if your device has the extra 1mm of space.

What is the difference between mAh and Wh on the label?

mAh (milliamp-hours) measures electric charge. Wh (Watt-hours) measures total energy. Wh is calculated as (mAh x Voltage) / 1000. Airlines use Wh limits (100Wh max) for carry-on rules, so the Wh label is vital for travel.

Do I need the UN38.3 mark on the battery itself?

Not always on the battery itself, but you absolutely need the UN38.3 Test Report from the manufacturer to ship the batteries legally. Some small batteries are too small to print the mark, so it goes on the packaging.

Why is there no C-rate on my battery label?

Low-discharge batteries (for Bluetooth headsets, etc.) often omit the C-rate because it is standard (1C or 0.5C). High-performance drone batteries will always display the C-rate prominently (e.g., 50C) because it is a key selling point.

Can I trust the date code on a generic battery?

Not always. Generic re-wrappers often buy old surplus cells and put new stickers on them. Buying directly from an OEM manufacturer like Hanery guarantees the date code reflects the actual production run.

What does “LiHV” on a label mean?

LiHV stands for High Voltage Lithium Polymer. It indicates the battery can be charged to 4.35V or 4.4V per cell. If you charge it like a standard 4.2V Li-Po, you won’t get the full capacity.

Why is the text on my battery label rubbing off?

High-quality labels use UV-cured ink or laser etching that resists solvents and abrasion. If the ink rubs off with a finger swipe, it is a sign of a cheap, low-quality manufacturing process.

Summary & Key Takeaways

The label on a Li-Po battery is a contract. It promises specific dimensions, energy capacity, and safety compliance. For the savvy engineer or procurement manager, the ability to decode this contract is the key to ensuring reliability.

Geometry is King: The model number (e.g., 503040) is your blueprint for fitment. Always allow tolerance for swelling.
Voltage Vigilance: Confusing Nominal (3.7V) with Max (4.2V) or Series (11.1V) voltages can be catastrophic.
Traceability Matters: Date codes and batch numbers separate fresh, high-performance cells from aging surplus.
Compliance is Non-Negotiable: Regulatory marks like UN38.3 and UL are not optional decorations; they are the keys to the global market.

At Hanery, we take labeling seriously because we take safety seriously. Our labels are accurate, compliant, and backed by verifiable test reports. When you source from Hanery, you don’t need a decoder ring to know you are getting quality—it’s printed right on the pack.

Secure Your Supply Chain with Trusted Power

Are you tired of guessing games with generic battery specs? Do you need a battery partner who provides transparent, compliant, and high-performance energy solutions?

Contact Hanery Engineering Team Today.Reach out for a consultation on custom battery design, accurate labeling, and global certification support. Let us power your product with truth and reliability.

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