Battery module, secondary battery and cap assembly thereof

Abstract

The present disclosure provides a battery module, a secondary battery and a cap assembly thereof. The cap assembly includes a cap plate which is provided with a terminal hole and an electrode terminal provided to the cap plate and covering the terminal hole; the electrode terminal includes an outer surface; the electrode terminal includes a positioning hole which is recessed with respect to the outer surface and includes a first portion and a second portion, the second portion is positioned to a side of the first portion away from the outer surface; a section of the first portion parallel to a central axis of the positioning hole is trapezoidal; a size of the first portion gradually decreases in a direction of the first portion close to the second portion, and a minimum size of the first portion is greater than or equal to a size of the second portion.

What is claimed is: 
     
         1 . A cap assembly for a secondary battery, comprising a cap plate and an electrode terminal;
 the cap plate being provided with a terminal hole, the electrode terminal being provided to the cap plate and covering the terminal hole;   the electrode terminal comprising an outer surface;   the electrode terminal comprising a positioning hole, the positioning hole being recessed with respect to the outer surface of the electrode terminal and comprising a first portion and a second portion, the second portion being positioned to a side of the first portion away from the outer surface;   a section of the first portion parallel to a central axis of the positioning hole being trapezoidal;   a size of the first portion gradually decreasing in a direction of the first portion close to the second portion, and a minimum size of the first portion being greater than or equal to a size of the second portion.   
     
     
         2 . The cap assembly according to  claim 1 , wherein the first portion has a first peripheral surface, an angle between the first peripheral surface and the outer surface is from 135 degrees to 175 degrees. 
     
     
         3 . The cap assembly according to  claim 1 , wherein the positioning hole further comprises a third portion, the third portion is cylindrical and is positioned between the first portion and the second portion. 
     
     
         4 . The cap assembly according to  claim 3 , wherein
 the first portion has a first peripheral surface;   the outer surface comprises a first region and a second region, the first region surrounds the first peripheral surface and is connected with the first peripheral surface, and the second region surrounds the first region and is connected with the first region;   a roughness of the first region is greater than a roughness of the first peripheral surface.   
     
     
         5 . The cap assembly according to  claim 4 , wherein
 a size of the second portion gradually decreases in a direction of the second portion away from the first portion;   the second portion has a second peripheral surface, the second peripheral surface is a circular arc surface.   
     
     
         6 . The cap assembly according to  claim 1 , wherein
 the first portion has a first peripheral surface;   the outer surface comprises a first region and a second region, the first region surrounds the first peripheral surface and is connected with the first peripheral surface, and the second region surrounds the first region and is connected with the first region;   a roughness of the first region is greater than a roughness of the first peripheral surface.   
     
     
         7 . The cap assembly according to  claim 4 , wherein the roughness of the first region is from 1 μm to 14 μm. 
     
     
         8 . The cap assembly according to  claim 1 , wherein
 a size of the second portion gradually decreases in a direction of the second portion away from the first portion;   the second portion has a second peripheral surface, the second peripheral surface is a circular arc surface.   
     
     
         9 . The cap assembly according to  claim 1 , wherein a shape of the second portion is different from a shape of the first portion. 
     
     
         10 . The cap assembly according to  claim 1 , wherein the electrode terminal comprises a first terminal plate and a second terminal plate, the first terminal plate is positioned to a side of the second terminal plate away from the cap plate;
 a material of the first terminal plate is different from a material of the second terminal plate;   
       the positioning hole is formed to the first terminal plate, and a depth of the positioning hole is less than a thickness of the first terminal plate. 
     
     
         11 . The cap assembly according to  claim 10 , wherein the first terminal plate is made of aluminum and the second terminal plate is made of copper. 
     
     
         12 . The cap assembly according to  claim 8 , wherein the cap assembly further comprises a fixing member, the fixing member connects the cap plate and the electrode terminal, an edge of the electrode terminal is positioned between the fixing member and the cap plate. 
     
     
         13 . The cap assembly according to  claim 1 , wherein the cap assembly further comprises a fixing member, the fixing member connects the cap plate and the electrode terminal, an edge of the electrode terminal is positioned between the fixing member and the cap plate. 
     
     
         14 . The cap assembly according to  claim 13 , wherein the electrode terminal is provided to a side of the cap plate. 
     
     
         15 . The cap assembly according to  claim 1 , wherein the electrode terminal is provided to a side of the cap plate. 
     
     
         16 . The cap assembly according to  claim 1 , wherein the cap assembly further comprises a connecting piece, the connecting piece is provided with a bulging portion, the bulging portion extends into the terminal hole and is connected with the electrode terminal. 
     
     
         17 . The cap assembly according to  claim 1 , wherein the cap assembly further comprises a sealing ring, the sealing ring is provided between the cap plate and the electrode terminal. 
     
     
         18 . A secondary battery, comprising an electrode assembly, a case and the cap assembly according to  claim 1 ;
 the electrode assembly being received in the case, the cap plate of the cap assembly being connected to the case, the electrode terminal being provided to a side of the cap plate away from the electrode assembly.   
     
     
         19 . A battery module, comprising the secondary battery according to  claim 18  and a busbar;
 the busbar being connected to the electrode terminal, and the busbar comprising a through hole aligned with the positioning hole of the electrode terminal in a height direction; 
 the through hole exposing the first peripheral surface, and a ratio of an exposed area of the first peripheral surface to a total area of the first peripheral surface being greater than ⅔. 
 
     
     
         20 . The battery module according to  claim 19 , wherein the busbar is welded to the second region of the outer surface, the through hole exposes at least part of the first region.