Interconnection bar and organic silica gel for battery modules

Interconnection bar

The interconnection bar is also called tin-coated copper tape and tin-coated tape, and the wider interconnection bar is also called a bus bar. The appearance is shown in Figure 1. It is a special lead for connecting the cell and the cell in the battery assembly. It is based on pure copper copper strip, and a layer of solder is evenly coated on the surface of the copper strip. Pure copper copper strip is oxygen-free copper or red copper with a copper content of 99.99%. The composition of the solder coating is divided into two types: lead-containing solder and lead-free solder. The thickness of the single-sided solder coating is 0.01~0.05mm, and the melting point is 160~230℃. The coating is required to be uniform, and the surface is bright and smooth. There are more than 20 kinds of interconnection bar specifications according to their width and thickness. The width can be from 0.08mm to 30mm, and the thickness can be from 0.04mm to 0.8mm.

Interconnection bar and organic silica gel for battery modules
Figure 1 – Outline drawing of interconnection bar

Organic silica gel

Organic silica gel is a sealant material with a special structure, which has good aging resistance, high and low temperature resistance, UV resistance, oxidation resistance, impact resistance, pollution resistance, waterproofing, and high insulation. Mainly used for the sealing of the frame of the battery assembly, the bonding and sealing of the junction box and the battery assembly, the pouring and potting of the junction box, etc. After the organic silica gel is cured, it will form a high-strength elastic rubber body, which has the ability to deform under the action of external force, and returns to its original shape after the external force is removed. Therefore, the battery components are sealed with organic silica gel, which will have the functions of sealing, buffering and protection.

Generally, there are two types of silicone for sub-battery components. One is a neutral single-component silicone sealant used to bond and seal the components with aluminum profile frames and junction boxes. Its main performance characteristics:

①Neutral curing at room temperature, fast deep curing speed, so that the surface cleaning and cleaning work of the group 1 can be carried out after 3 hours; ②Good airtightness, good adhesion to aluminum, glass, TPT, TPE backplane materials, junction box plastics, etc.; ③The colloid is resistant to high temperature, yellowing, unique curing system, and has good compatibility with all kinds of EVA; ④The ability of components to resist mechanical vibration and external impact can be improved.

The other is a two-component silicone thermal conductive adhesive used for junction box potting. This kind of silica gel is a new type of thermally conductive and insulating material synthesized from organic silicon. Its main performance characteristics are: ①Cure at room temperature, fast curing speed, no heat, no corrosion, and small shrinkage rate during curing; ②It can maintain rubber elasticity in a wide temperature range (-60~200℃), with excellent electrical performance and good thermal conductivity; ③Waterproof and moisture-proof, chemical resistance, yellowing resistance, weather aging resistance for more than 25 years; ④Good adhesion to most plastics, rubber, nylon and other materials. Common organic silica gel is shown in Figure 2.

Interconnection bar and organic silica gel for battery modules
Figure 2 – Commonly used organic silica gel