Meeting the Quality Challenge in Rechargeable Battery Manufacturing

The way we use batteries has changed a lot over the past decade. To meet the growing demand for electric vehicles (EVs) and modern digital electronics, today’s batteries are expected to occupy much smaller dimensions, while packing more energy. The key to developing safe, durable rechargeable batteries for these markets is precision quality control.

^{This article is posted on our Science Snippets Blog}

An electric vehicle is shown with the main body removed to reveal the rechargeable battery pack

Inside the rechargeable battery

Rechargeable batteries are made of one or more electrochemical cells, which is where electrical energy is generated. A battery cell contains electrodes (anode and cathode materials), an electrolyte medium that contains ions, and a separator that allows ions to travel between the electrodes during charge and discharge.

Today’s batteries must satisfy stringent performance and safety requirements. This is especially true of batteries designed for EVs, as even a minor flaw in one of the battery cells can impact performance or increase fire risk! To meet standards, battery manufacturers implement automated production lines with integrated quality testing at every stage.

White Paper: Precision Production of Lithium-Ion Batteries for Electric Vehicles

Ensuring quality at every step

Manufacturers rely on technologies that accurately recognize quality defects, while tolerating the fast pace of production. Sartorius provides industry-trusted weighing solutions and other essentials like ultrapure water, filtration products, and data analytics for several steps of the rechargeable battery manufacturing process.

The workflow below shows the development lifecycle of a typical rechargeable battery and the places where Sartorius technologies and expertise can help bring high quality batteries across the finish line.

Battery manufacturing workflow showing the specific applications supported by Sartorius solutions

Preparing the electrodes

In the first stage of battery manufacturing, electrode material (e.g., lithium-metal oxides) and binders are combined into what is called an electrode slurry. Using highly pure slurry components is key to producing high quality batteries, so density checks and compositional analysis at this step provide vital information about the purity of lithium, manganese, graphite, plastics, and other raw materials.

Next, a thin layer of slurry is deposited onto a long foil and compressed through a process called calendering. Moisture control along this process is vital, as even small traces of water can ruin battery components. Thermogravimetric moisture analyzers are used to measure water content during QC of raw materials and after drying steps. Analyzers that provide moisture data fast and precise are ideal here.

Building the battery cell

Once the electrode rolls are notched, it’s time to assemble the electrochemical cells. Here, the separator is applied between the sheets of electrodes and placed inside a casing. Finally, the casing is filled with the correct amount of liquid electrolyte and sealed. Assembled cells go through an aging and charging process before final testing.

In-line weighing sensors put manufacturers in full process control by providing precise data on every component. Sartorius weigh cells, for example, can be integrated at different stages to check for correct dosing of slurry constituents, as well as electrolyte dispensing and cell assembly. Such precise controls flag deviations before defective products advance to the next stage.

eBook: OEM Weigh Cells & High-Resolution Load Cells

Making data work for you

Producing high-quality batteries involves a lot of data— some manufacturing plants generate close to 700 million characterization data in just one day. Without digital tools like design of experiment (DOE) and multivariate data analysis, there is no simple way of translating such complex datasets into useful insights.

Analytics software suites like Umetrics^® can really simplify data handling, putting manufacturers in control of their data. For example, DOE modeling can help de-risk projects and bring battery products to the market faster and at a lower cost. Artificial intelligence-driven tools, like multivariate data analysis provide real-time monitoring of the entire production line, allowing faster troubleshooting.

Getting there with confidence

A few decades ago, the average consumer only needed batteries for a flashlight or a toy remote-control car. Today, lithium-ion batteries are powering smart phones in virtually every purse or pocket. Green initiatives are also encouraging more car buyers to go fully electric; Bloomberg New Energy Finance estimates that by 2040, EVs will make up 58% of all car sales.

Battery developers are at the forefront of these trends, and they need robust tools to confidently navigate complex manufacturing processes and meet rigorous quality requirements. Sartorius supports many applications throughout the battery development workflow and helps manufacturers ensure quality from raw ingredients all the way to the final product. Visit the battery applications page to learn about solutions for battery manufacturing and recycling.