A tab-through device, assembly apparatus, and assembly method for a battery are disclosed. The battery includes a housing and an electrode assembly. The housing is provided with an accommodation chamber, and a through hole is formed in the housing. The electrode assembly is arranged in the accommodation chamber. The tab-through device is configured to guide a tab part of the electrode assembly to extend out of the through hole. The tab-through device includes a clamping mechanism and a driving mechanism. The driving mechanism is configured to drive the clamping mechanism to clamp the tab part within the accommodation chamber to extend out of the accommodation chamber through the through hole. According to the above method, the present application can effectively reduce the assembly difficulty of the battery.