What Is the Story: Rights in the Space the Module Left Behind
Patent competition over cell-to-pack (CTP: a structure that places cells directly into the pack without bundling them into modules) is not a fight over the fact that “the module was removed,” but over claiming “what replaced the structural support, fixing, and thermal management functions the module used to perform, and how.” The idea of removing the module is itself broad and abstract, making it difficult to protect as such; the actual scope of rights is decided by the shape and joining method of the replacement components. This article organizes that structure through each company’s officially announced figures and one registered patent.
Starting with the industry landscape, on June 23, 2022 CATL unveiled its third-generation CTP technology, the “Qilin battery,” cracking the traditional cell-module-pack assembly sequence. CATL announced that this product reaches a volume utilization rate (the share of pack volume actually occupied by cells) of 72%. This structure, which eliminates the intermediate module stage and places cells directly into the pack, is no longer CATL’s technology alone. LG Energy Solution has introduced a pouch-type CTP, and Samsung SDI and CATL have each introduced prismatic-based CTP, approaching the same goal through their own distinct structural patents.
The tension lies in the role the module used to carry. Removing the module reduces space and part count, but the structural rigidity, cell fixing, and impact absorption functions handled by the module case disappear with it. Who replaces those functions with which components decides both product performance and the scope of patent rights at the same time. This article answers two questions. In a structure without modules, what becomes the subject of a claim? And what infringement risk and design-around room do structural patents registered in the module era leave for CTP designs?
Basic Principle: Stacking Goods on Shelves Without Boxes
A conventional battery pack goes through three stages: bundling multiple cells into a module, then assembling modules together into a pack. The module case served as both a cushioning material and a structural support, but it also took up a corresponding amount of space and weight. CTP is an approach that omits this module stage and fills the resulting free space with more cells.
Source: reconstructed by the editorial team from CATL announcements (2019, 2022)
By analogy, the module is a “box” inside a warehouse. Packing goods (cells) into boxes and stacking them makes them easy to move and keeps them from knocking into one another, but warehouse space is wasted by the thickness of the box walls. CTP removes the boxes and places the goods directly on shelves. Space increases, but partitions, holders, and cushioning have to be newly designed into the shelving itself so that the goods do not collapse.
For this reason, the CTP design challenge comes down to splitting what the module did into three parts and relocating them.
- Structural support: members that bear the swelling force of the cell stack and external loads (end plates, beams, pack housing walls)
- Fixing and fastening: how the cell stack is joined to the pack housing (welding, bolting, bonding)
- Thermal management: a pack-level cooling structure replacing module-level cooling plates
CATL announced that in the Qilin battery it integrated internal parts such as the conventional crossbeam and thermal pad into a “multifunctional elastic interlayer,” and that by changing the water-cooling structure it increased the heat transfer area fourfold and cut thermal control time in half. The description cited in the original article, “a combination of vertical structures (partitions) between cells and a liquid-cooling system,” points in the same direction as this announcement. In other words, what the module did was not eliminated but relocated, with several functions layered onto a single component.
Comparison: CTP-Family Structures in Officially Announced Figures
The table below collects only figures that each company officially announced. Because the definitions of the metrics (volume utilization efficiency, space utilization) and the baselines differ by company, it is safer to read it for “what each company emphasized, and against what baseline” than to compare the numbers directly.
| Item | Announced | Officially announced figures | Baseline |
|---|---|---|---|
| CATL CTP 1st generation | 2019-09-13 | Volume utilization efficiency up 15-20%, pack part count down 40%, system energy density from 180 Wh/kg to over 200 Wh/kg | Versus conventional module-based packs (improvement) |
| BYD Blade Battery | 2020-03-29 | Pack space utilization up by over 50% | Versus conventional LFP block batteries (improvement) |
| CATL Qilin (CTP 3rd generation) | 2022-06-23 | Volume utilization 72%, energy density up to 255 Wh/kg (ternary) and 160 Wh/kg (LFP) | Absolute value at pack level |
Source: compiled by the editorial team from the CATL press release (2022-06-23), Xinhua report (2019-09-13), and BYD announcement (2020-03-29)
What this table says: CATL’s first-generation “15-20%” and BYD’s “over 50%” are both improvement margins, but their baselines differ, so neither can be ranked above the other. Qilin’s 72%, by contrast, is an absolute value, showing that industry figures are shifting from “how much it increased” to “how much it filled.”
This difference matters for patent interpretation too. Depending on whether a specification states its effect as an “improvement rate over modules” or as an “absolute volume utilization rate,” the inventive-step argument against prior art and the way numerical limits are placed in claims may differ. Mixing officially announced figures with numerical definitions from patent specifications can undermine the logic of an FTO (freedom-to-operate, infringement clearance) report.
Patent Perspective: The Question an End-Plate Patent Poses to CTP
Subject patent: KR102106448B1 (title “Battery pack”) is a patent filed by Samsung SDI on December 11, 2017 and registered on May 4, 2020. According to Google Patents its legal status is Active with an anticipated expiration of December 11, 2037, and it was published as KR20190069130A on June 19, 2019. A U.S. patent claiming priority from the same application, US11031648B2, was granted on June 8, 2021.
Gist of the claim (paraphrased): Claim 1 combines a plurality of battery cells arranged in one direction, an end plate placed outside the outermost cell, and an end block placed between them. The end block has a frame portion that faces the cell side and surrounds the cell’s edges, and an end portion on the opposite side that surrounds a bush member. The bush member is divided into a fixing portion surrounded by the end portion and an exposed portion that is exposed outside the end portion and forms a welded portion with the end plate. The specification explains that this structure reduces the number of components and assembly steps, lowering manufacturing cost, which is the same concern as the part simplification and cost reduction CTP pursues.
Source: reconstructed by the editorial team from the claims of KR102106448B1 and US11031648B2
Filing trend: This patent does not directly claim a structure without modules. Rather, it presupposes a member familiar from module-type structures, one that clamps both ends of the cell stack with end plates. What is interesting is the language of effects. The goal of “fewer parts and fewer process steps” points in the same direction as the “40% reduction in pack part count” CATL announced for its first-generation CTP in 2019. This means that module-era fastening-structure patents and CTP patents are claiming the same effect through different configurations.
Design-around points: Claim 1 requires all of the end plate, the frame portion of the end block, the fixing and exposed portions of the bush member, and the welded portion between the exposed portion and the end plate. Under the all-elements rule, if even one of these is missing, literal infringement is difficult to establish. Accordingly, a CTP structure in which the pack housing wall directly presses the cell stack without an end plate, or a structure that fastens the bush by bolting or bonding rather than welding, may fall outside the literal scope of the rights.
Design-around scenario (counterargument): Conversely, if the side wall of the pack housing effectively performs the same function as an end plate (pressing and fixing both ends of the stack) and a metal insert is welded to that side wall, infringement risk under the doctrine of equivalents could be debated. Merely renaming the part a “side wall” does not guarantee avoidance; whether function, way, and result are substantially the same may become the issue. Meanwhile, the numbers and owners of patents directly claiming CATL’s “multifunctional elastic interlayer” or its combined partition and water-cooling structure could not be confirmed from public patent information within the scope of this article, so they are left as tracking points.
- Tracking point 1: distribution by applicant of claims on pack structures integrating inter-cell partitions (beams) with cooling plates
- Tracking point 2: remaining term and regional registration status of claims on structures in which the housing presses the cell stack without end plates
Limits and Outlook
Removing the module gains space and cost, but a trade-off remains: the cushioning structure that absorbed external shocks disappears with it. The industry assesses that even CATL tried to offset the concern that “removing the module lets you pack in more battery but may leave it vulnerable to external shocks” through vertical structures and a cooling system. Although each company attaches its own name, such as CTP, Blade Battery, or Ultium battery, the essence of the patent competition appears to be converging on “what replaces the work the module used to do, and how.”
The optimistic outlook is that as the volume-utilization race continues, CTP becomes the standard pack structure. But there is also a counter-scenario. If demand for cell replacement and reuse grows, structures that integrate cells into the pack may be at a disadvantage in repairability and recycling processes, and in that case modules or equivalent replaceable units may return to designs. At that point, the infringement risk from already registered end-plate and end-block patents could grow again.
A strategic alternative is to classify and manage pack-structure patents by “functional unit” rather than by “module or no module.” If you map, for each of the three functions of structural support, fastening, and thermal management, which component your design has layered which function onto, you can compare module-type and CTP-type patents on the same basis and reduce the need to redo FTO from scratch with every design change.
Practical action: Planning and IP staff designing or reviewing a CTP pack should list the members that press both ends of their pack’s cell stack and how they are fastened (welding, bolting, bonding), compare them line by line with the claim elements of KR102106448B1 and US11031648B2, and record in advance any potential for an equivalents-infringement debate.
Items requiring verification
- Official announcement dates and specifications of LG Energy Solution’s pouch-type CTP and Samsung SDI’s prismatic-based CTP
- Numbers, applicants, and registration status of patents claiming the inter-cell partition and water-cooling structure of CATL’s Qilin battery
- The original source of the industry assessment that “removing the module may leave it vulnerable to external shocks”
- Examination outcome of the European application in the KR102106448B1 family (EP3496182A1)
Sources
- Google Patents, KR102106448B1 – Battery pack (Samsung SDI)
- Google Patents, US11031648B2 – Battery pack (Samsung SDI)
- CATL, “CATL launches CTP 3.0 battery Qilin, achieves the highest integration level in the world” (2022-06-23)
- Xinhua, “China’s CATL unveils cell-to-pack battery platform” (2019-09-13)
- BYD Europe, Blade Battery announcement (2020-03-29)