What Is CTP Technology That CATL and BYD Are Promoting?

Recently, CTP has appeared more frequently in the lithium battery manufacturing field and is gaining public attention. Some investors even ask battery makers on public channels: how is your CTP R&D progressing and when will it be implemented in vehicles?

Atonm reviewed CTP approaches used by major battery manufacturers and shares possible CTP solutions to clarify the concept.

1. What is CTP

Traditionally, battery cells are assembled into modules, and modules are assembled into a battery pack (Pack), forming a three-level structure: cell - module - pack.

CTP, or Cell To PACK, integrates cells directly into the pack and removes the intermediate module structure, simplifying the pack, improving space utilization and reducing complexity.

There are two main CTP routes: a fully module-less design and schemes where large modules replace many small modules.

Option 1: Fully module-less approach - BYD Blade Cell

BYD developed long cells longer than 0.6 meters that insert into the pack like blades arranged in arrays. This so-called blade cell CTP design increases volumetric energy density and reduces part count.

BYD CTP scheme

Compared with traditional pack structures, BYD reports a roughly 50% increase in volumetric energy density and a cost reduction with longer range claims.

Option 2: Large modules replacing many small modules - Tesla, CATL, Others

This approach reduces the number of modules by enlarging each module so that fewer modules are needed.

(Example CTP scheme)

2. Advantages and disadvantages of CTP

Advantage 1: Simplified structure and improved space utilization

CTP reduces endplates, side plates and fasteners, improving volume utilization. Fewer parts reduce weight and can increase pack energy density and vehicle range.

Advantage 2: Simplified assembly and lower production cost

CTP can simplify assembly steps, reducing labor and manufacturing costs, and lowering parts cost for the pack.

(Pack structure comparison)

Disadvantage 1: Loss of module-level protection increases risk from a single cell failure

CTP requires higher cell consistency. Issues such as expansion during charge cycles and uneven cooling must be addressed. A failed cell may force replacement at pack level, increasing maintenance cost.

Disadvantage 2: Requires redesigned control architecture

Without module boundaries, thermal runaway protection and BMS sampling strategies must be rethought to ensure safety and proper control.

3. Outlook for CTP

Why are battery makers promoting CTP so actively? Partly this is a strategic and commercial consideration.

Battery production has high investment and high technical barriers, making it hard for many automakers to fully control cell manufacturing. By offering CTP, battery makers can capture more value by selling fully integrated packs rather than only modules. Some OEMs announce adoption of supplier CTP packs while other firms continue to explore CTP options.