Case Study: Powder handling in battery production
As the world increasingly shifts towards renewable energy, batteries have become an essential component of energy storage. However, the production of high-quality batteries requires a complex process that involves various manufacturing stages, including bulk material handling. The handling of powders plays a crucial role in battery production as it involves the transportation, storage, and processing of powdered materials used in battery electrodes. The handling also requires a delicate balance between ensuring their purity, preventing (cross) contamination, and maintaining optimal conditions for their physical and chemical properties.
Furthermore, the trend towards electric mobility and energy storage is driving the demand for lithium and other raw materials such as cobalt, nickel, and manganese, particularly in battery manufacturing. In the demanding production chain of batteries, the supply of raw materials is the first but important step for the quality of the end product. Here again, powder handling plays a significant role in the battery's lifespan and performance. In addition to explosion protection measures, containment aspects must also be considered.
Manufacturing of battery masses
HECHT Technology realizes and offers state-of-the-art discharging, conveying, and dosing technologies for the production of various battery components. The main focus is on the continuous and precise supply of raw materials for the production of cathodes and anodes. The protection of the users and the product is the central concern.
Our customer is a well-known battery manufacturer based in Germany.
The installed combination system consists of an anode line and a cathode line. Both lines consist of two separate and independent subsystems. Essentially, the same process is carried out in each subsystem, starting at the feeding stations.
In the system, the powdered components are fed, conveyed, and dosed into a customer-supplied mixing vessel. The powder is then used in the subsequent process steps for the production of electrode paste for lithium-ion battery electrodes. In total, two mixing stations with corresponding product feeds were supplied.
Functional description
The main components for the anode and cathode materials are loaded into dust-free big bag emptying stations. Big bag emptying stations essentially consist of four components: a connection system as the core component for safe discharging, a support table to secure suspended loads, a frame for mounting the connection system, and a lifting device. The big bag emptying stations implemented at the customer's site are additionally equipped with a lump breaker, which eliminates agglomerates and lumps before conveying and dosing.
First, the big bag is connected to the HECHT liner connection system LAS-EC for closed product handling. This system is characterized by a defined, safe handling process with a logical operating sequence in a few steps, ensuring easy, ergonomic, and secure discharge of powders. Even during the change of big bags, the system remains closed to the environment, preventing any product dust from being released outward. This allows compliance with the required OEB-4 level for NMC products.
The materials required for battery manufacturing, such as carbon black and graphite, are relatively non-critical for the operator and are typically handled without OEB level specifications. However, the HECHT liner connection system LAS-EC for OEB level 4 was used for emptying these products, primarily for the sake of cleanliness in the environment and to prevent potential cross-contamination.
Small quantities of these materials are delivered in bags of various sizes and are emptied in a dust-free manner. The bags are introduced into a discharge station with a glovebox through a feeding/lock system. The bags are then opened and emptied through glove ports. The empty bags are disposed of in a liner through a side chute. A ball valve suction shoe with an agitator below the glovebox transfers the product to the pneumatic conveying system, ensuring consistent bulk material quality and particle size distribution.
In the next step, the powder is transported to the dosing station using a vacuum conveyor (PCC). The HECHT ProClean Conveyor PCC is a highly efficient, very flexible pneumatic conveyor designed for long conveying distances and the safe transport of explosive or toxic materials. A separate conveying system is used for each product. The conveying devices also serve as storage vessels from which dosing takes place into the customer's mixing vessel. The required accuracy was easily achieved (primary weighing, withdrawal weighing).
If multiple materials are conveyed into a mixing vessel, this is done sequentially according to a predefined recipe. Up to three different solids can be conveyed into the mobile mixing vessel. The number of products and conveying devices can be expanded if needed. After each individual dosing, the dosing result in the mixing vessel is checked using control weighing. The mixing vessel is located in an extraction cabin and is sealed with a pneumatically operated cover. The cover is equipped with connections for components and ventilation.
Subsequently, in the customer's mixer, the so-called electrode paste is produced by adding liquid. This paste is then applied to a metal substrate in the further process, dried, and cut. Separator films, made of porous plastics, are placed between the two electrodes to prevent short-circuiting. In the final step, the electrodes and separators are stacked in layers and enclosed in a casing, which is filled with an electrolyte that transports ions between the electrodes. Finally, the casing is sealed to prevent electrolyte leakage.
Recycling process
Not only battery manufacturing is a complex process, but recycling is also an important aspect in reducing the environmental impact of hazardous chemicals. However, there are several challenges that make the battery recycling process difficult. Specifically, carbon black is both a useful and potentially hazardous substance when inhaled. The fine particles can enter the lungs and cause respiratory problems. For this reason, safety precautions must be taken when using carbon black.
arbon black can be obtained from used batteries through a recycling process called pyrolysis. Pyrolysis is the thermal decomposition of organic materials in an oxygen-free environment. In the case of batteries, they are first mechanically crushed and disassembled into their individual parts. The battery parts are then heated in an oven under oxygen-free conditions. The heat breaks down the organic materials in the battery, resulting in a mixture of liquid and gaseous components, as well as carbon black. The resulting mixture is then processed in various steps to separate and purify the carbon black from other components. The recovered carbon black can be used in other applications such as rubber and plastic manufacturing or reused in battery production. Other materials are also recovered through recycling, such as lithium, cobalt, nickel, and carrier foils made of copper or aluminum.
To safely and securely fill and prepare these products for transport in the final step, HECHT offers various containment conveying and/or filling stations.