A123 Systems has been granted a patent for a new electrode design for lithium-ion batteries. The electrode includes a current collector with two sides, one of which is coated with two layers of different binders and weight ratios. This design reduces internal resistance and improves adhesion within the electrode. GlobalData’s report on A123 Systems gives a 360-degree view of the company including its patenting strategy. Buy the report here.
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According to GlobalData’s company profile on A123 Systems, Battery management systems was a key innovation area identified from patents. A123 Systems's grant share as of September 2023 was 53%. Grant share is based on the ratio of number of grants to total number of patents.
Electrode for lithium-ion battery cell with improved adhesion and decreased internal resistance
A recently granted patent (Publication Number: US11769882B2) describes an electrode design for lithium-ion batteries that aims to improve their performance. The electrode consists of a current collector with two opposing sides, one of which is coated with two layers. The first layer, called the first coating layer, is applied at a higher loading and contains a first binder in a higher weight ratio. The second layer, called the second coating layer, is applied on top of the first layer at a lower loading and contains a second binder in a lower weight ratio. Both layers also contain electrochemically active material in the form of particles, with the thicker coating layer having smaller particles than the thinner coating layer. The weight ratio of the first coating layer to the second coating layer is less than 1:2.
The patent also describes additional features of the electrode design. The ratio of the first coating layer loading to the second coating layer loading is between 1:100 and 1:3. The average calendering density of both coating layers is between 1.6 g/cc and 2.0 g/cc, and the calendering density of each layer is at least 1.7 g/cc. The thickness ratio of the first coating layer to the second coating layer is between 1:99 and 3:7. The binders used in the coating layers can include polystyrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), and various acrylate polymers. The coating layers also contain conductive additives such as carbon black and carbon nanotubes (CNTs). The electrochemically active material in the electrode can be graphite, and its particle size in the first coating layer is less than or equal to 9 µm.
The patent also includes a claim for a lithium-ion battery cell that incorporates the described electrode design. The cell has an anode and a cathode, with one or both of them containing a current collector coated with the first and second coating layers. The first coating layer does not contain any electrochemically active material, while the second coating layer does. The first conductive additive in the first coating layer can be CNTs, while the second conductive additive in the second coating layer can be carbon black. The first conductive additive has a greater surface area than the second conductive additive. The electrochemically active material in the cell can have a bimodal or trimodal particle size distribution. The opposing sides of the current collector can also have an interfacial region where the first and second coating layers partially mix.
The patent further includes a method for manufacturing the described electrode. The method involves forming two slurries, one with a higher binder content and the other with a lower binder content, and simultaneously coating the current collector with these slurries to form the first and second coating layers. The coated current collector is then dried and calendered at a predetermined density. The ratio of the loading of the first slurry to the second slurry is less than 1:2, and the thicker coating layer has smaller particles than the thinner coating layer. The simultaneous coating can be performed using a slot die configuration or two rollers positioned within five meters of each other.
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GlobalData Patent Analytics tracks bibliographic data, legal events data, point in time patent ownerships, and backward and forward citations from global patenting offices. Textual analysis and official patent classifications are used to group patents into key thematic areas and link them to specific companies across the world’s largest industries.
