Laser Welding of Lithium-ion Cylindrical Module

Lithium Batteries are quickly becoming the norm in batteries. Lithium batteries are so named due to the lithium anode used in the construction of these cells. Lithium batteries stand apart from other cells in a couple of different ways. First, Lithium cells have a high discharge density and have the ability to charge and discharge very efficiently. Lithium Cells are commonly used in Portable Electronics, Radio Controlled hobbies, and Electric Vehicles. 

There are several main types of Lithium Battery Cells. Prismatic, Pouch, Cylindrical, and Button Cells. Each of these cells are compatible with welding. Below we will discuss each of them and welding applications of each of these cells.  

Prismatic Lithium Cells

Prismatic Lithium Cells are one of the more common types of Lithium Battery cells. They are commonly used in cell phones, tablets, cameras, and in electric vehicles. A prismatic cell consists of the anode, cathode, separator, and electrolyte wrapped in a metal container. Each prismatic cell is custom made for each application, and there is hardly any crossover from cell to cell. Prismatic Cells are generally safer than most lithium cells, and provide an added layer of protection, as they are sealed in a metal case. 

Welding Prismatic Cells

There are a variety of applications for welding​ prismatic Cells. 

• Weld tabs and multiple layers of current collectors

• Welding multiple layers of foils

• Weld Tabs Together to create battery assemblies

• encase and seal cases and covers.

• Cell to Cell Joining

• Module to Module Joining

Lithium Pouch Cells

Lithium pouch cells consist of stacked layers of anodes, separators, and cathodes sandwiched in between layers of the laminated film. These pouch cells can be created in custom sizes and shapes. Each Pouch cell provides 3-4 volts. Pouch cells are then connected in series and parallel to acquire the desired voltage, and capacity. In a pouch cell configuration, the S in the number specifies how many are in series, and the P specifies how many pack assemblies. For example, if you have a 4s4p pack, this would be a total of 16 cells. 4 packs of 4 cells each. 

Welding Lithium Pouch Cells

Lithium pouch cells can be welded in a number of ways, both in the creation and in the assembly process. 

Applications:

• Hermetic sealing of custom Pouches

• Welding Layers to Lead tabs

• Creating Lead tabs

• Cell to Cell Connections

• Module to module Connections

  
  

Prismatic Cylindrical Lithium Battery Module Welding Fixture

A Prismatic Cylindrical lithium battery module welding fixture, including a left baffle plate, a right baffle plate, a bottom plate, a welding side plate, a clamping cylinder, a left clamping assembly and a right clamping assembly.

1. The left clamping assembly includes the left vertical plate of the clamp, the clamping plate and the clamping connecting rod;
2. The clamping plate is a "bow" type, and the middle of the clamping plate is set in the middle of the top of the left vertical plate of the fixture;
3. There are two clamping connecting rods, the lower end of the clamping connecting rod is hinged on the left baffle plate of the clamp, and the upper end of the clamping connecting rod is hinged in the "bow"-shaped groove of the left clamping plate;
4. The structure of the clamping assembly is the same as that of the clamping assembly on the left side of the fixture.

Advantages: The clamping lifting plate of the clamp is lifted up by the clamping cylinder, so that the clamping elements on the upper part of the left baffle and the right baffle of the clamp clamp the lithium battery module, which ensures the reliability of clamping.