Common lithium battery tape

Lithium battery tape is a pressure-sensitive adhesive tape used in the middle production process of lithium battery cells for electrode winding, electrode protection, and core termination. Its primary function is to provide insulation and fixation on lithium batteries. The development of lithium-ion batteries has accompanied the development of battery tape.
Lithium battery tape is a pressure-sensitive tape with unique functional characteristics, which has specific initial viscosity, holding viscosity, temperature resistance, and chemical corrosion resistance. It can be reused without pollution and has no pollution to the surface of the adhered material after peeling.

Mainly determined by factors such as substrate, adhesive, and usage lithium battery tapes are generally classified according to substrate, adhesive, and usage.
There are various types of lithium battery tapes, and manufacturers often develop and produce lithium battery tapes based on customer requirements for material use. Among them, the composition of the adhesive determines the characteristics and uses of lithium battery tapes. Commonly used adhesives include acrylic adhesive, rubber adhesive, etc.
Lithium battery tapes prepared using different adhesives as raw materials have different characteristics:

• The acrylate lithium battery adhesive tape prepared with acrylate adhesive has good aging resistance, weather resistance, high-temperature resistance, good thermal stability, good adhesion to polar surfaces, low adhesion to non-polar surfaces, and low initial peel strength.
• The rubber lithium battery adhesive tape prepared with rubber adhesive has higher shear resistance at high temperatures and good initial adhesion with various surfaces but poor aging and solvent resistance.

Preparation of lithium battery tape

Substrate treatment: PP, PET, and PI film substrates are treated with a surface corona discharge to obtain a rough and smooth film substrate. Coating release agents can also obtain release films on nonadhesive surfaces or by adding a layer of digital ink to get a digital cinema;
Gluing, applying pressure-sensitive adhesive on the corona surface of the film, and drying and curing the adhesive through a high-temperature drying channel;
Roll up, cool down through equipment, and then roll up according to specifications to obtain semi-finished products;
Cutting, the mother roll obtained during the winding of semi-finished products needs to be rerolled and then cut or cut into strips to get the finished product, which can be packaged and sold.

The substrate is the carrier in lithium battery tape, which affects factors such as temperature range, tensile strength, shear strength, and material cost of lithium battery tape.
Typical substrates include BOPP, PET, PI, and nomex paper;

• Polymer films are commonly used as carrier substrates for lithium battery tapes due to their excellent properties such as size stability, high elasticity, good insulation, acid and alkali resistance, good tear resistance, and resistance to plasticizers.
• Different substrates endow lithium battery tapes with various characteristics, and the temperature resistance of the substrate determines the upper limit of the temperature environment and temperature resistance performance. PI substrate>PET substrate>BOPP substrate has the best temperature resistance performance, while BOPP substrate has the worst temperature resistance performance.
• The cost of the substrate is opposite to its temperature resistance, with BOPP lithium battery tape having the lowest cost and PI lithium battery tape having the highest price.

With the development of new materials, the lithium battery tape industry has introduced some new types of adhesives, such as single-sided hot melt lithium battery tape and double-sided hot melt tape for lithium batteries.

• The single-sided hot melt lithium battery tape comprises a sealed hot melt pressure-sensitive adhesive layer and a base film layer. The single-sided tape has good adhesion, can withstand the corrosion of the electrolyte in the lithium battery, does not react chemically with the electrolyte inside the lithium battery, and maintains the performance of the lithium battery. The lithium battery pole group and outer packaging material are firmly bonded using single-sided hot melt lithium battery tape, without relative displacement, with good impact resistance, high safety, long service life, and stable quality.
• One side of the double-sided tape used for lithium batteries is sticky, usually acrylic adhesive; The other side is nonsticky at room temperature and becomes sticky when exposed to heat, typically hot melt adhesive. During use, one side of the tape has adhesion to aluminum foil and polyethylene film at room temperature. In contrast, the other side needs to be above 80 ℃ to have adhesion to the polypropylene surface, which is more suitable for the production process requirements of lithium batteries.

Lithium battery termination tape refers to the pressure-sensitive adhesive tape used for electrode winding and core termination in the middle production process of lithium battery cells. This type of tape has the general properties of pressure-sensitive tape and special requirements for substrate selection, adhesion, temperature resistance, and electrolyte resistance. It is a particular type of pressure-sensitive adhesive product.
Lithium-ion battery termination tape is a commonly used type of pressure-sensitive tape in batteries.

With the miniaturization development of various electronic devices, the market has become increasingly demanding on the size and thickness of batteries. As a result, the thickness of lithium battery materials is also required to be thinner.

The current market demands controllability and traceability of product quality, and lithium battery digital termination tape is another type of lithium battery termination tape developed to meet this market demand.
It is to add a printed digital label on the lithium battery termination tape, and its performance requirements are consistent with the lithium battery termination tape. Digital tape usually consists of an adhesive layer, a protective layer, an ink layer, a base layer, a base layer, and a release layer to form the tape structure. It is based on biaxially stretched PET or PP film as the substrate, with printing ink as the digital functional layer. The non-digital surface of the substrate is coated with a single component nonsilicon release agent as the unwinding coating. Apply an acrylic adhesive layer on the surface of the substrate to make a lithium battery digital tape.
Lithium battery high-temperature resistant tape
Lithium battery is a high-temperature resistant tape developed to ensure the excellent stability of lithium batteries under high-temperature limit conditions such as production and use. It requires lithium batteries to maintain structural stability and chemical properties for a long time in high-temperature environments, ensuring that lithium batteries do not short-circuit, leak electricity, or leak liquid in high-temperature environments.
The initial high-temperature-resistant tape for lithium-ion batteries was organic silicone tape. Still, in recent years, the lithium-ion battery industry has proposed that the battery cells should not contain silicon elements. Therefore, most of the high-temperature resistant tape currently used is acrylic acid battery.

When making lithium battery cells, it is necessary to weld a Tab lead on the pole ear, which lengthens the pole ear and facilitates the following process of melting the sealing agent for sealing when sealing the top side.
Tab lead welding uses ultrasonic welding; after welding is completed, solder joints will be on the pole ears because the height and position of the pole ear extension may not meet the requirements.
Generally, it is necessary to bend the pole ear, which can easily cause short circuits. Therefore, insulation tape must be applied to the welding position, and both sides of the pole ear must be coated with insulation tape.
Double-layer lithium battery protective film tape
The shell of a lithium battery is complex and has clear diamond corners. The protective edge of the lithium battery tape requires softness, strong adhesion, good adhesion, and long-term nonwarping. This type of tape is called a double-layer lithium battery protective film tape.
The composite structure of double-layer PET film and double-layer adhesive layer makes the adhesive tape more flexible while being wear-resistant and tough;
Coating a high viscosity modified acrylic adhesive with added phenolic resin makes the adhesive stronger, resulting in better tape adhesion, less warping, and no residue after baking at 130 ℃ for 0.5 or more, which can better protect the battery.

Power battery tape is a battery tape that uses PET film as the substrate and is coated with nonsilicon pressure-sensitive adhesive PET film. It is used for insulation, maintenance, and fixation of the shell of power batteries in electric vehicle soft packaging, the battery cells set inside the shell, the top cover of the shell, the top surface of the battery cells, the two sides, and the bottom surface.
Lithium battery protection film: The lithium battery protection film tape mainly uses PET film and BOPP film as substrates, coated with acrylic adhesive, and is used for pasting and protecting the surface of aluminum-plastic film in the production process of soft pack batteries and polymer lithium battery cells.
The characteristics are high cleanliness, moderate viscosity, no warping when pasting aluminum-plastic film, no damage to the strip spray code, high-temperature resistance without residue, scratch resistance, puncture resistance, and product compliance with ROHS standards.