Ben Lincoln of Potter Clarkson says monitoring the patent filings of competitors is a worthwhile strategic practice that can offer significant advantages to businesses. He takes a look at the recently published patent applications of LG, Samsung, CATL and BYD.

By keeping a close eye on the innovations and technological advancements being pursued by rivals, companies can gain valuable insights into market trends, emerging technologies and potential threats. In essence, monitoring competitors’ patent activities is a crucial component of a comprehensive intellectual property strategy, enabling businesses to stay ahead.

LG Electric

US 18/578,696, published on 21 November, relates to an improved negative electrode for a lithium secondary battery including a protective layer. The protective layer is formed by coating a solution containing a metal fluoride, a binder and a lithium salt on a lithium metal layer.

This protective layer suppresses the growth of lithium dendrites. A further advantage is that during operation of the battery, a layer containing lithium iron is also formed between the lithium metal and the protective layer, thereby improving lifetime characteristics and performance of the battery.

US20240387946, published on 21 November 2024, relates to improving the capacity and lifetime of the battery by coating the surface of a base separator that sits between the positive electrode and the negative electrode of the battery with a conductive carbon-metal oxide mixture.

In particular, the conductive carbon used is thermally-expanded reduced graphene oxide and the metal oxide is manganese dioxide. The advantage of this coated separator is that excellent discharge capacity and lifetime characteristics are shown regardless of the type of the electrolytes used in lithium-sulphur batteries (Fig 1).

Other publications relate to methods for manufacturing a secondary battery having reduced resistance and simultaneously having an improvement in both cell stiffness and mechanical durability (EP4465405 – published November 2024).

Other publications relate to the construction of battery cell casings with specific geometries (US20240380082 – published November 2024), while others relate to improved sealing gasket materials (US20240380043) such that even when the temperature of the cylindrical battery rises or the cell is subject to impact, the gasket is not deformed. This thus reduces the likelihood of internal short circuits.

Many of LG’s recent patent applications relate to refinements over all parts of the cell and its manufacture.

Samsung SDI

US20240387803, published on 21 November, relates to an active material for a cathode in which a radial arrangement structure and an irregular porous structure of the active material is implemented. This can allow the active surface area useful for lithium diffusion to be increased. This can lead to a lower occurrence of cracks during charging and discharging cycles, thereby improving lifetime of the battery (Fig 2).

EP4456174, published in October, relates to an all-solid secondary battery wherein the solid electrolyte layer comprises a sulfide-based solid electrolyte. Looking at the patent register reveals numerous filings covering relatively general principles of all-solid cells going back several years.

EP4446980 from October relates to a method for detecting black spots on a battery separator. The black spot is indicative of small internal short circuits in the battery. The claimed method dramatically improves a discovery ratio of black spots and provides an automated method that is more accurate.

After checking the prosecution history, the European Patent Office has not found any relevant prior art and the patent application should progress to grant without objection.

CATL

Patent US20240356156, published in October, relates to a binder composition for secondary batteries that reduces the proliferation of gaps between the separator and the active layers. Thus, the improved binder can lead to improved lifetime of the battery and improved performance (Fig 3).

US20240356057 published in October relates to a structural arrangement for applying a top compression plate to a battery cell in a way that reduces the pressure applied to the electrodes and can reduce the risk of damage, thereby providing a safer battery cell.

BYD

CN118221141, published in June 2024 relates to an improved method for extracting lithium from brine. The method requires a lower energy consumption compared to existing methods and requires less alkali materials. Furthermore, the use of multiple centrifugal precipitation steps reduces the reliance on nanofiltration membranes and so results in a more cost effective extraction method.

WO2024046410, published in March, relates to a silicon-carbon electrode material which has good conductivity and good structural stability. Silicon nanoparticles are distributed between the pores of porous carbon to form the Silicon-Carbon electrode material. The pore structure can disperse silicon nanoparticles, the problem caused by the expansion of concentrated regions of silicon particles.

Thus, BYD’s recent filings not only relate to details of the battery cells but also lithium extraction techniques.

Patterns in recent filings

As may be expected, many of the larger players are filing patent applications to protect refinements to their lithium-based cells.

One pattern that can be seen is a greater number of patent filings for sodium-ion based cells. Looking at the recent publications, BYD, CATL and Guangzhou Great Power Energy & Technology Co. are all very active.

For example, CATL’s patent application EP4465403 claims a negative electrode active material of hard carbon and a positive electrode active material that comprises one or more of sodium transition metal oxides having particular particle sizes and compositions.

BYD has also published applications relating to methods of making the hard carbon material for use with its sodium-ion batteries. CN118231656 relates to a method of preparing a biomass-based hard carbon material and includes the following steps:

• pre-carbonising the biomass, and then cooling the obtained carbonised material and then crushing, acid washing and water washing in sequence
• soaking the carbonised material obtained after the treatment in step (1) in a metal salt solution, and then drying and carbonising; wherein, the pre-carbonisation temperature is lower than the carbonisation temperature.

Overall, the recent patent filings show a diverse range of R&D activity with the majority of the patent filings relating to incremental improvements. However, it can also be seen that some of the companies are pursuing different technologies and attempting to protect their area of research for the future.