CTB

CTB (Cell-to-Body, battery-body integration technology) is an electric vehicle manufacturing technology that deeply integrates the traction battery pack's top cover or cells directly into the vehicle's body and chassis structure. Unlike conventional "battery pack fitted into chassis" setups, CTB technology eliminates the physical boundary between the battery and the body. This allows the battery pack to function not only as an energy storage unit, but also as a structural load-bearing component that withstands body torsion, bending, and crash loads, thereby significantly improving cabin space utilisation and overall body rigidity.

Core Technical Architecture and Operating Principles

The CTB architecture primarily comprises a high-strength integrated battery top cover/floor design, high-density module-less (CTC/CTB) cell packaging, and optimised body load transfer paths. 

Two-in-One Integration of Battery Top Cover and Body Floor:

In conventional manufacturing, the cabin floor and battery pack top cover are two separate panels. Under the CTB architecture, however, the battery pack's top cover doubles as the cabin floor, with the cells secured directly inside the battery tray using structural adhesives or high-strength fasteners. This layout eliminates redundant vertical bulk and slims down the battery pack height, significantly improving cabin headroom and lowering the vehicle's centre of gravity.

Multi-Dimensional Load Paths & Enhanced Torsional Rigidity: 

Front, rear, and side impact loads are channelled through purpose-engineered load paths straight into the battery pack's side members and internal longitudinal beams, which are built from high-strength steel and aluminium alloys. The battery pack is no longer just dead weight bolted under the chassis; it actively contributes to structural rigidity as a core load-bearing member. This substantially increases the vehicle's torsional rigidity, effectively enhancing body stability during high-speed cornering and under severe crash conditions.

Safety Guidelines and Physical Limitations 

Strict Prohibition of Continued Driving After Severe Undercarriage Scrapes or Structural Damage:

Because the battery pack in a CTB layout serves as an integral load-bearing structure, any severe undercarriage scraping, crushing, or tearing not only jeopardises the physical integrity of the cells inside, but can also compromise the stress balance of the entire chassis. Continuing to drive after undercarriage damage must be strictly avoided; an immediate high-voltage isolation inspection and structural safety assessment are mandatory to prevent thermal runaway.

Strict Prohibition of Unauthorised Cutting and Welding on CTB Chassis or Battery Side Rails:

Under the CTB architecture, the battery side rails and body structure feature intricate structural engineering and material strength gradients. Unauthorised cutting, drilling, or welding on battery pack side rails or critical integrated chassis load points during repairs or aftermarket modifications is strictly prohibited. Doing so compromises crash load transfer paths, stripping the vehicle of its engineered impact resistance and occupant protection capabilities in subsequent collisions.