Export Lithium Battery Packaging: The Real Boundaries of UN38.3, Class 3 Test Report Ownership, Cushioning and Thermal Insulation Liners, and Outer Box Markings — The First 3 Numbers a Printer Should Ask When Accepting a Lithium Battery Packaging Order

In May 2026, a factory producing energy storage power supplies sent us a printing request for a batch of outer boxes. The boxes were ordinary five-layer corrugated paperboard, not large, and contained lithium iron phosphate cells. The customer sent us a PDF and said, “Print this on the side of the box.”

The PDF contained a UN38.3 Test Summary. Its format was neat, with headings, a number, and a signature. We laid it out and printed 3000 boxes.

Three days after the goods arrived at the port, the customer sent us a message:

“The goods were detained. The shipping line said the issue date on the Test Summary was 2 days earlier than the production date of our cell batch. They would not accept it and requested a new document.”

The printing company made only one mistake—we copied the document without verifying the correspondence between its date and batch. But another point is more important: the Test Summary should never have been the printing company’s responsibility to verify in the first place.

The issuing party for a UN38.3 Test Summary is the battery or battery pack manufacturer. What a printing company may receive could be a transcript, a customer-signed copy, or even a sample downloaded from an official website. These 3 documents have completely different legal standing, yet they look identical in a design file.

The central boundary of lithium battery packaging can be expressed in one sentence: a printing company prints information, but the authenticity of that information belongs to someone else. The problem is that this is usually not explained clearly to the printing company.

First Boundary: Test Report Ownership — What the Printing Company Should and Should Not Request

First, clarify the concepts. UN38.3 is a test standard for the transport of lithium batteries. The Test Summary is issued by the battery, battery pack, or battery manufacturer to demonstrate that the batteries comply with transport requirements. This document is not something a printing company or brand owner can issue.

What the printing company should request from the customer is a written confirmation, not the original report. The confirmation should state which cell or battery pack batch the Test Summary corresponds to, its issue date, and its current validity status.

Our factory adds 3 boxes to the order confirmation: the cell batch number corresponding to the Test Summary, the issue date, and the confirmation signature of the party providing it. We do not release the artwork unless all 3 are completed.

There is also a time dimension: a Test Summary is not permanently valid. If a cell manufacturer changes its supplier, protection circuit, or structure, a new Test Summary is required. Boxes printed by the printing company may remain in circulation at sea for several months or even a year, so we need to ask the customer: how long are these boxes intended to be used, and are older Test Summaries from earlier batches being mixed into inventory.

One final point concerns the printing company’s own boundary: do not add information to the box that is not included in the Test Summary. For example, some customers request additional dangerous goods markings such as “UN3480” and “Class 9” on the box. These are packaging markings governed by destination-country rules and are separate from the Test Summary. They must be confirmed by a qualified party. There is no problem with a printing company following the instruction, but the design confirmation should separately record that these are markings confirmed by the customer independently, rather than combining them with the Test Summary approval.

Second Boundary: Cushioning and Thermal Insulation Liners — This Is a Packaging Structure, Not a Printing Task

The cushioning and thermal insulation liner inside a lithium battery outer box is the most technically demanding part of this order and is also the part most likely to be treated by a printing company as “the packaging company’s responsibility,” resulting in complete unfamiliarity with it.

The liner must solve 3 problems: short-circuit prevention, vibration protection, and thermal-runaway propagation prevention. These objectives require entirely different material solutions.

Common configurations combine several solutions:

• Short-circuit prevention—insulating caps fitted to cell terminals, or insulating partitions inserted between terminals, typically using insulating foam or PET separators;
• Vibration protection—EPE foam, honeycomb paperboard, or high-density EPS, relying primarily on structural energy absorption;
• Thermal-runaway propagation prevention—this objective depends on thermal insulation rather than cushioning materials. Heat-resistant insulating materials such as mica sheets are commonly attached to the sides of the cells.

The printing company’s actual role in this order is: printing on the outside of the box and supplying the liner inside the box. Many printing companies accept these orders by treating the liner as “customer-supplied” without asking a single question.

After encountering a problem, however, we changed our rules. It involved an export order for cells whose liner had been made by a packaging company selected by the customer using ordinary EPE. We printed the outer box and added dangerous goods markings, making the packaging fully compliant.

The customer later reported that one box had caught fire during sea transport—not the cells themselves, but the EPE liner had collapsed under high temperatures, allowing the cells to shift and short-circuit. When responsibility was investigated, the customer said that we had printed the outer box and its markings.

Ultimately, we were not held liable because the outer box and liner were separate components. Nevertheless, after that incident, we added a requirement to the confirmation form for every lithium battery order: state in writing who supplies the liner and whether the liner design matches the box dimensions. The internal dimensions of the box and the external dimensions of the liner must be matched. If the customer commissions the liner from another packaging company, a liner that is 2 mm too large either will not fit inside the box or will not sit securely.

Another specific set of numbers is equally important: the compressive strength of the outer box and the number of stacking layers. Lithium battery outer boxes generally need stacking and vibration tests in accordance with dangerous goods packaging requirements. The box material, whether five-layer or three-layer corrugated paperboard, along with the scoring positions and bonding method, must all correspond to the required performance.

Our factory’s recommendation is: use five-layer corrugated paperboard for lithium battery outer boxes and keep the box dimensions as small as practical to lower the center of gravity after packing. For the same batch of cells, changes in box size can result in a 20% difference in freight costs—often making freight a higher expense than printing in lithium battery exports.

Third Boundary: Outer Box Markings — 3 Types of Markings, Each With Its Own Rules and Responsible Party

Markings on lithium battery outer boxes fall into 3 categories, each governed by different rules and confirmed by a different party. This is the area where printing companies most need to distinguish responsibilities.

One detail of the dangerous goods markings is easily overlooked: the lithium battery pictogram differs from other dangerous goods. It consists of a slash and a battery symbol, with a numeric identifier below indicating the type of battery; different types have different handling requirements. This number cannot be printed arbitrarily. It is determined by the shape and quantity of the batteries and will still be detected if printed incorrectly.

It is also necessary to distinguish “lithium batteries shipped alone” from “lithium batteries packed with equipment”. Their marking requirements differ, and the former requires more information, including the number of packages and the number of batteries. When a customer says, “It’s just lithium batteries,” the printing company must ask: Are they shipped alone, or packed with equipment?

Gross weight in the transport markings also requires attention. Gross weight and net weight are two different figures, and their difference is the weight of the packaging materials. Some customers usually print only the net weight, while others require both. The most common printing company error is to treat a customer-provided net weight as the gross weight. The declared weight on the box is then lower than the actual weight, the carrier calculates charges based on the actual weight, the freight forwarder cannot reconcile the figures, and the boxes must be opened and reweighed.

The shipping mark section follows the same specifications as export corrugated boxes and can be referenced in our article about export corrugated box type codes. The real difficulty is that the box number and shipping mark must exactly match the bill of lading and packing list, and these documents are often supplied by the freight forwarder only 1 day before container loading, leaving the printing company caught in the middle.

Our practical solution is: leave a blank area for the shipping marks and use a separate digital printing process. This allows box numbers to be printed shortly before container loading, without destroying the entire batch of boxes merely to change a few numbers. This practice is nearly standard for lithium battery export orders.

The First 3 Numbers a Printing Company Should Ask When Accepting This Type of Order

If only 3 numbers may be requested, I would ask for:

First: the model and batch number of the cells or battery pack. These 2 figures determine which version the Test Summary corresponds to and provide the only basis for checking whether a transcript contains copying errors. A verbal statement from the customer such as “the same as last time” is insufficient. The information must be documented in writing.

Second: the net weight of a single cell and the number of cells packed per box. These 2 figures determine the outer box dimensions, how gross and net weights are calculated, and how freight costs are calculated. Lithium battery export freight is often directly linked to weight. Whether the cells fit efficiently and whether they pack economically are effectively the same issue.

Third: the internal dimensions of the box and the external dimensions of the liner. These 2 figures must be matched. Our factory has seen cases where a large batch of liners was completed, only to discover that the box’s internal dimensions had been undersized by 3 mm, making the liners impossible to fit and turning the entire batch of liners and boxes into waste. This measurement must be confirmed during the design stage, not the sample-making stage.

After obtaining these 3 numbers, ask the customer to document on the confirmation form “who issued the Test Summary, which batch it corresponds to, and who signed the confirmation.” Only then is the order ready to enter production.

Further Reading

• The Real Boundaries of Export Dangerous Goods Packaging UN Performance Level Class 3: Packaging Type Codes / Relative Density / Pressure Test Values—although it uses the same UN system, lithium battery boxes and general dangerous goods boxes have different test items. This article explains the basic framework.
• The Real Boundaries of CLP / GHS Class 3 Hazardous Chemical Packaging Labels—pictograms and H statements form an adjacent but separate system from the marking rules for lithium battery boxes.
• The Real Boundaries of Export Corrugated Box FEFCO/ESBO Type Codes Class 3: 5 Details Missing When Customers Specify Only “0201”
• First-Time E-Commerce Gift Box Procurement: A Comparison of the Actual Damage Rates of 3 Scenarios—Tote Box vs Mailer Box vs Shipping Box—although it does not involve lithium batteries, the principles for calculating stacking strength are the same.
• The Real Boundaries of Packaging Specifications Class 3: Dimension Standards / Material Models / Process Inspectability—the 3 areas most likely to conflict with actual conditions in the table provided when a customer places an order.