TotalEnergies Lubrifiants, a division of TotalEnergies SE (France), has introduced a novel immersion-cooled battery system for electric vehicles, using its proprietary non-conductive fluid called “Cell-Shield”. This technology has been implemented in production models, including the Renault Mégane E-Tech and a Volvo XC90 plug-in hybrid.
The system works by directly submerging battery components in the dielectric fluid, which improves thermal management. Reported outcomes include a 50% reduction in charging time, 6% increase in vehicle range, and enhanced safety by limiting the spread of thermal runaway. The system is also said to provide a more efficient cooling mechanism than traditional systems, demonstrating sevenfold thermal performance, along with a 4% mass reduction and a 5.6% cost savings.
TotalEnergies’ strategic investments in integrated power and mobility
As part of its broader renewable energy transition, TotalEnergies SE announced that 30% of its capital expenditures will go to its Integrated Power business, which includes projects in solar, wind, and battery storage. Storage efforts are handled by its subsidiary Saft and supported through the Automotive Cells Company (ACC), a joint venture with Stellantis and Mercedes-Benz that targets over 120 GWh of battery output by 2030.
In electric mobility, TotalEnergies operates over 25,000 EV charging stations in Europe, aiming to reach 150,000 by 2025. It also launched “Source”, a joint venture with SSE to install 3,000 ultra-fast chargers across the UK and Ireland.
The company has also developed products like Quartz EV and Rubia EV3R, which use re-refined base oils and 50% recycled plastic. It is also scaling its hydrogen infrastructure through a partnership with Air Liquide, aiming to deploy over 100 stations for heavy-duty vehicles.
In this article, we take a closer look at TotalEnergies’ approach to electric vehicle thermal management, focusing on how its Cell-Shield fluid and related patent activity support efficiency and safety.
TotalEnergies: Patenting Activity
TotalEnergies’ patent filings have grown significantly over the years, reflecting an aggressive push into renewables like electrification, battery systems, and sustainable mobility. Global filings rose from 2019, peaking in 2022. The company’s 2021 rebranding marked a broader shift toward low-carbon energy and integrated clean technology solutions.
The rise in filings aligns with key corporate moves, including the 2011 acquisition of a majority stake in solar company SunPower, the 2016 purchase of battery manufacturer Saft, and the launch of Automotive Cells Company (ACC). Hutchinson, a long-standing TotalEnergies subsidiary, has also played a key role by contributing thermal interface materials and protective enclosures for EV batteries. In 2022, TotalEnergies also partnered with Global Infrastructure Partners to invest in Clearway Energy Group, one of the largest renewable energy platforms in the U.S.
TotalEnergies: Top Jurisdictions
From 2015-2025, TotalEnergies pursued a strong global patent strategy, with significant activity in Europe and North America. Key granted patents were in France, the United States, Germany, and through the European Patent Office, reflecting a focus on core markets. TotalEnergies’ extensive geographic spread of patent filings, particularly through the World Intellectual Property Organization (WO), reflects its strategic use of the PCT route to secure international protection. This approach enables broad market coverage across regions like Europe, North America, and Asia, reinforcing the company’s commitment to globally scaling its innovations in clean energy and electrification.
TotalEnergies: Top Law Firms
TotalEnergies partnered with a range of IP firms to manage its growing patent portfolio. Lavoix served as the primary representative, followed by Plasseraud IP, solidifying its position as a crucial partner in TotalEnergies’ IP protection strategy in Europe.
August Debouzy also supported TotalEnergies in international mergers and acquisitions, regulatory affairs, and strategic intellectual property disputes. Bandpay & Greuter and Gevers & Orès also contributed significantly, offering strong regional insight and technical depth. This strategic distribution of legal and technical partners underscores TotalEnergies’ integrated approach to safeguarding its innovations globally.
TotalEnergies: Top Technology Areas
TotalEnergies amassed a portfolio that reflects its ongoing transformation from a fossil-fuel giant into a clean energy innovator. The portfolio is heavily concentrated on lubricant technologies for engines, industrial machinery, and increasingly, electric drivetrains (C10M). This is followed by chemical to electrical energy processes (H01M), highlighting a major shift toward battery and fuel cell innovation. This surge supports the company’s ambitions in electrified mobility and stationary energy storage, particularly through its battery subsidiary Saft.
Patents under C08L and C08F classifications emphasize innovations in polymer-based materials, crucial for lightweight EV components, thermal management systems, and safe battery enclosures. Meanwhile, activity in C10L and C10G reveals an ongoing investment in synthetic fuels and cleaner hydrocarbon processing, aiding the transition period toward net-zero.
Complementing these efforts are notable filings in catalysis (B01J), geophysical sensing (G01V), and material analysis (G01N), which underpins TotalEnergies’ ventures in carbon capture, hydrogen production, and underground storage.
Together, these patent trends reflect a balanced approach: leveraging core expertise in chemistry and fuels, while scaling up in batteries, sustainable materials, and climate-aligned technologies—an embodiment of TotalEnergies’ ambition to be a multi-energy leader for a decarbonized future.
Cell-Shield fluid technology
Overheating and thermal runaway remain major challenges in modern battery systems, especially in electric vehicles. In response, TotalEnergies, along with its subsidiaries Saft America and Hutchinson, has developed a suite of complementary innovations under its advanced “Cell-Shield” approach. These solutions address critical safety and performance issues through integrated strategies for thermal containment and management, aiming to prevent thermal propagation and enhance overall system stability.
Three key patents form the foundation of the Cell-Shield technology, each offering a distinct yet coordinated mechanism to improve battery safety and efficiency.
Simpler, safer battery cooling system
When a single battery cell malfunctions, it can rapidly heat up, potentially reaching temperatures of 400 to 800°C. This intense heat can spread to neighboring cells, causing a chain reaction that can lead to the entire battery pack failing, and in some cases, fire or explosion. Preventing this spread of thermal runaway is a major challenge in battery design.
WO2024236154A1 offers a simplified and cost-effective solution to battery thermal management. Rather than relying on complex and expensive pump-driven cooling systems, this invention directly immerses battery cells in a specially formulated dielectric fluid. The key to this system lies in the fluid’s high “thermal expansion.” As a cell overheats, the surrounding fluid warms, becomes less dense, and naturally rises, drawing heat away from the cell. This creates a continuous, natural circulation that effectively cools the overheated cell and disperses excess heat throughout the battery, preventing damage to other cells.
By eliminating the need for pumps and intricate plumbing, the battery’s construction is simplified, reducing costs and increasing reliability due to fewer potential points of failure. The design also facilitates the management and venting of flammable gases that may be released during a cell failure, further improving battery safety. Ultimately, the system presents a more elegant and robust approach to managing the thermal challenges of high-energy batteries, paving the way for safer and more economical energy storage solutions.
The patent application titled “Battery cooling system incorporating a dielectric fluid without forced convection” was filed on May 16, 2024, and published on November 21, 2024. Nicolas Champagne, Niranjan Edappady, Gérard Quoirin, Jonathan Raisin, and Alexandre Meunier are listed as the inventors, and August Debouzy represented TotalEnergies in the patent filing.
Doubling EV fast-charging speed
Current battery manufacturing often uses a gel-like polymer electrolyte for enhanced safety and leak prevention. However, the gelling process can leave unreacted liquid chemicals. During the initial charge, these residues can form a detrimental crust on the electrode surface, significantly hindering performance, reducing power output, and shortening the battery’s lifespan.
Adding LiDFOB salt to the liquid mixture before gel formation creates a more reactive compound. This ensures that during the crucial first charge, LiDFOB preferentially coats the electrode which establishes a pristine, stable, and highly efficient protective layer. This proactive measure effectively prevents the formation of undesirable deposits.
U.S. Pat. App. No. 2024/0039045 shows that batteries made with this new process retain their storage capacity over hundreds of charge-discharge cycles, unlike the rapid degradation seen in conventionally manufactured batteries. Additionally, the refined manufacturing process includes an intelligent partial charge while the electrolyte is still liquid. This allows for the expulsion of trapped gases before the gel solidifies, a crucial “burping” step that ensures the creation of a more robust and dependable battery, ideal for demanding applications.
The patent application, titled “Method for in-situ thermal polymerization of a gel polymer electrolyte in a lithium-ion electrochemical cell” was filed on July 29, 2022 and published on February 1, 2024 to Saft America. Tyler Ruff and Jacob Nykaza are listed as the inventors. Alan Kasper, William Mandir, Mark Boland, et.al from Sughrue Mion PLLC represented Saft America in the filing.
Hybrid cooling system for EV batteries
Electric vehicle batteries generate significant heat and require efficient cooling to perform safely and last a long time. A major challenge is ensuring a tight, gap-free connection between the cooling system and the hot battery components. While rigid metal cooling plates are strong, they often leave small air gaps that hinder heat transfer.
U.S. Pat. App. No. 2025/0140981 introduces a hybrid cooling device that merges the key advantages of both flexible pouches and rigid frames. The system centers on a slender, flexible casing with internal channels for liquid coolant circulation, securely fastened along its edges within a two-part rigid support structure. Notably, the bottom section of the rigid frame includes a substantial opening directly beneath the flexible casing.
This configuration leverages the strengths of both components. The rigid frame provides essential mechanical stability and a secure mounting point, allowing the unit to be precisely positioned over the battery cells. As coolant flows through the flexible casing, internal pressure causes it to expand and protrude through the frame’s opening. This enables the flexible surface to make direct contact with hot battery components, eliminating air gaps and enabling highly efficient thermal transfer. The result is improved battery performance and a longer operational lifespan.
The patent application, titled “Cooling Device for an Electric Battery” , was filed on October 28, 2024 and published on May 1, 2025 to Hutchinson. Jean-Yves Mounier, Nicola Moretti, and Franco Viroglio are listed as the inventors. Steve K. Barton, Curtis Vock, Douglas Link et al. from Cozen O’Connor represented Hutchinson in the filing.
Next steps in TotalEnergies’ clean energy strategy
TotalEnergies continues to advance its renewable energy projects across Europe and the Caribbean. Recently, TotalEnergies developed a 263 MW solar cluster expected to generate 515 GWh annually in Spain. Equipped with 400,000 bifacial panels, the project will supply electricity to 150,000 homes and reduce 245,000 tons of CO2 emissions.
In Germany, TotalEnergies secured the 1 GW N-9.4 offshore wind concession in the North Sea, boosting its 23 GW global offshore wind capacity. In the Caribbean, a partnership with AES Dominican Republic will involve LNG supply and renewable expansion, fostering energy transition via solar, wind, storage, and cleaner thermal sources. Additionally, TotalEnergies is collaborating with Mistral AI to establish an innovation lab, applying artificial intelligence to areas such as low-carbon energy systems, operational efficiency, emissions reduction, and digital infrastructure.
