The Proof: Copper Tabs Make a Better Battery

Apr 14, 2021

In 2019 the global electric vehicle market exceeded USD $270 billion, according to Fortune magazine. The market, which includes battery electric vehicles, plug-in hybrids, and hybrid electric vehicles, is expected to grow to a trillion-dollar industry by 2027. At the heart of this industry is the battery pack. Success rises and falls on the sophisticated battery packs used in modern-day electric vehicles. Different manufactures use different battery cell types, connection methods, and configurations. But the one thing common to every battery is they need a weld.  

Sunstone recognizes the vital need for welding within this massive battery market, and the company has worked to develop new technologies that push the limits of what is possible. One specific area of focus is copper battery tabs. Copper has metallurgical advantages, including low resistance, inexpensive cost, and thermally conductive, which make copper ideal for use in batteries and battery connections. In the past, copper has been tough to weld in a production setting. Through years of research and development, Sunstone has a solution that allows for welding copper directly to cells at mass production rates.  

How much does copper make a difference? 

That's a great question. In response, I developed a test that would clearly illustrate the differences in tab material. With help from a colleague, I used three different tab materials; cooper-, nickel-, and nickel-plated copper. Each tab was 0.015" (.38 mm) thick. I chose the Sunstone Omega battery welding system for the test, as it is specifically designed for batteries and copper. I used an empty battery with four welds per can, which allowed us to test the maximum amount of current in a simulated environment of one tab welded to two separate battery cans, similar to what you would see in the construction of any battery pack.  

We then passed various electric current amounts through the tabs and measured several variables to see how they reacted. The goal was to see how the various tab materials would respond to different currents and ultimately see the maximum amount of current they could handle before failing.

We found that cooper reduced the amount of heat produced in the tab by 71% over nickel and 40% over nickel-clad copper. That is a significant decrease in the amount of heat generated by the tabs. Heat is one of the most important contributing factors to battery degradation and reduced lifespan. By reducing heat in the pack, the life of the battery significantly increases. 

Another interesting test was to apply a fixed current of 200 Amps at 12V to these same tabs and measure the tab's heat over time. A constant current was applied until the battery tab failed or exceeded 300 C. The nickel tab lasted for 19 Seconds before exceeding the max temperature. The nickel-plated copper tab lasted longer but eventually failed after 33 seconds.  The copper tab steadily increased in temperature and reached 300C after 90 seconds. You can see the results of the test in the graph below.

The test was designed to illustrate the benefits of copper tabs over nickel or clad. Results showed that copper can handle a higher current load while generating significantly less heat. 

The short answer to my test is this: If you are not using copper tabs in your battery pack, you should be. Copper is a game changer. You can design your pack in a whole new way and get the high discharge capacity you really want. The Sunstone Omega battery welding system allows you to create custom packs matter of minutes, as it is designed to be used in a high production environment for mass production. Call Sunstone and see how you can destroy the competition with copper.