Coin Cell Battery Assembly Method and Precautions

Transfer the prepared pole piece to an inert atmosphere glove box,Prepare button battery assembly parts: negative electrode case,  lithium metal chips, separator, gasket, spring sheet, positive electrode case, electrolyte, in addition to the pressing mold, pipette and insulating tweezers.

The assembly process is shown in the figure below: place the negative electrode shell flat on the insulating table, place the  lithium metal chips in the center of the negative electrode shell, and use a tablet pressing mold to flatten the metal lithium sheet.

Then place the diaphragm flat on the upper layer of the lithium sheet, and use a pipette to take an appropriate amount of electrolyte droplets onto the surface of the diaphragm. Use insulating tweezers to place the test pole piece, gasket, spring piece and positive electrode shell on the upper layer of the battery separator in turn, and the active material side of the test pole piece needs to be close to the separator (Figure 6).

Further, place the negative side of the button battery on the mold of the button battery crimping machine with insulating tweezers, use a paper towel on the top of the battery to absorb the overflowing electrolyte, adjust the pressure (usually 800Pa) and press for 5s to complete the assembly and preparation of the button type. The battery, removed with insulated tweezers, observed whether the preparation was complete (Figure 7) and wiped clean with a paper towel.

In a coin half cell with metal lithium as the negative electrode, the negative electrode material in the full cell is actually the positive electrode in the coin cell at this time.

In a button battery, it is necessary to ensure that the diameter of the separator > the diameter of the lithium plate > the diameter of the pole piece.When moving the entire button battery with tweezers, insulating tweezers are required to prevent short circuit between the positive and negative electrodes. In order to ensure the later electrochemical test items and take into account errors and operational errors, the number of button batteries or simulated batteries assembled in the laboratory with the same material is generally not less than 5.

In the step of placing the lithium sheet in the preparation process of the button battery and the simulated battery, the smooth edge of the lithium sheet should be placed on the side of the separator. The burrs on the edge of the sheet pierce the separator and cause the cell to short circuit.

Each component of the button battery and the analog battery needs to be cleaned before use. The stainless steel parts can be ultrasonically cleaned with degreasing detergent, acetone, ethanol and water in turn. When cleaning with degreasing detergent, the cleaning temperature can be appropriately increased to reach The purpose of removing oil stains on the surface of components.

Teflon parts are cleaned with several other reagents besides acetone.The cleaned parts need to be dried in an oven. When simulating the battery assembly and placing the pole pieces, it should be noted that the pole pieces are prone to move and flip. When adjusting with tweezers, it is prone to breakage of pole pieces and side leakage of electrolyte. It is recommended to use blunt insulating tweezers.