US8337725B2 And 5 Similar Patents Powering Safer Lithium-Ion Batteries

Batteries power everything today, from smartphones to electric cars. But one of their long-standing weaknesses is safety, especially when they heat up. The glue-like materials, called binders, that hold battery components together can lose strength at high temperatures, leading to swelling, poor contact, or even failure.

Most of these binders are made from a plastic called PVDF, which has limits under stress.

US8337725B2, filed by Solvay, tackles this head-on. Instead of sticking with PVDF alone, it introduces a new fluorinated plastic combined with water-attracting acrylic units. The result is a semi-crystalline material that stays stable under heat, bonds better inside the battery, and offers a safer path forward for high-performance lithium-ion cells.

Though now part of a legal case between Solvay and Zhejiang Fluorine Chemical, we won’t focus on litigation here. Instead, we’ll explore how US8337725B2 works and where it fits within the evolution of advance battery materials.

To place it in context, we used the Global Patent Search (GPS) platform to surface similar inventions, highlighting how different innovators have approached the same challenge of safer, longer-lasting batteries.

Understanding Patent US8337725B2

US8337725B2 introduces a binder material designed to solve the challenge of keeping lithium-ion batteries stable under heat while still maintaining strong internal adhesion. To achieve this, the patent combines a tough fluorinated plastic (vinylidene fluoride, or VDF) with small amounts of water-attracting acrylic monomers.

The result is a copolymer, i.e., a chain-like structure that is rigid enough to withstand stress yet flexible enough to adapt inside the battery. This balance makes the material suitable not only for electrodes in lithium-ion cells but also for water-based membrane systems, where both heat resistance and compatibility are essential.

Source: Google Patents

The Key Features Of This Patent Are:

1. Fluorinated base structure: The main part of the polymer is made from VDF, known for its strong chemical and heat resistance.

2. Hydrophilic additive units: Small amounts of hydrophilic (water-attracting) monomers like acrylic acid are added to improve adhesion and wetting.

3. Even distribution of additives: The hydrophilic parts are spread evenly throughout the polymer, which helps the material stay stable at high temperatures.

4. Pressure-controlled manufacturing process: The polymer is made using a method that keeps pressure above a certain level, allowing better control over how the ingredients mix.

The polymer has a random structure that avoids blocky sections, improving heat resistance. A high-pressure process with slow chemical feeding ensures this even distribution. Its semi-crystalline nature gives it both flexibility and strength. These qualities make it suitable for use without extra hardening treatments.

In short, US8337725B2 offers a binder that is heat-resistant, adhesive, and versatile, making it valuable for both lithium-ion batteries and filtration membranes.

Similar Patents To US8337725B2

To explore the material innovations behind US8337725B2, we used the Global Patent Search tool to find similar technologies. These references focus on fluorinated copolymers used in lithium-ion batteries, especially in separators, electrodes, and membranes. Each takes a different approach to solving heat, stability, and conductivity challenges in battery design.

1. US6630271B1

US6630271B1 introduces a new class of electrolyte polymers designed for lithium rechargeable batteries. These polymers are made from vinylidene fluoride (VDF) copolymers that conduct ions well while also staying strong under heat.

As we know, traditional battery films often lose strength or conductivity when exposed to high temperatures. This patent solves that by carefully controlling how much comonomer is added to the VDF base. The result is a material that keeps its structure, absorbs liquid electrolytes effectively, and still allows fast ion movement.

These polymers can be shaped into thin films that act as separators, anodes, or cathodes, making them a flexible solution for improving both safety and performance in lithium-ion batteries.

What This Patent Introduces To The Landscape

1. VDF copolymers made for use in lithium battery membranes and electrodes
   
2. High ionic conductivity above 10⁻³ S/cm at room temperature
   
3. Materials that stay stable even after repeated heating up to 80°C
   
4. Films created through simple casting with low-boiling solvents
   
5. Carefully balanced comonomer ratios to keep mechanical strength intact

How It Connects To US8337725B2

• Both use VDF copolymers to improve battery material performance
  
• Each focuses on heat resistance and durability in battery environments
  
• This patent improves conductivity, while US8337725B2 enhances adhesion and hydrophilicity
  
• Both control polymer structure to get more reliable, high-performing films

Why This Matters

This patent shows how structure and chemical balance affect battery film performance. It adds to the growing field of VDF copolymers that make lithium batteries safer and more efficient, goals shared with US8337725B2.

Recommended Read: For a broader view of how technologies like US8337725B2 connect with industry progress, explore leading innovators in renewable energy storage here.

2. CN1328104A

CN1328104A describes a method for making water-based adhesives used in lithium-ion battery electrodes.

Instead of relying on harmful organic solvents, this process uses emulsion polymerization to mix hydrophilic and oil-like monomers into a stable binder. The result is a latex adhesive that works with common battery materials like graphite and lithium cobalt oxide, while offering adjustable viscosity for easier processing.

This invention improves worker safety, reduces environmental impact, and still delivers the strong adhesion needed for durable battery electrodes.

What This Patent Introduces To The Landscape

1. A water-based adhesive made from both hydrophilic and oil-like monomers
   
2. A method that avoids using soap-like chemicals or surfactants
   
3. Adhesives with adjustable viscosity (200–20,000 cP) and solid content (5–40%)
   
4. Works with common battery materials like graphite and lithium cobalt oxide
   
5. Uses safe processing conditions between 30–80°C over 5–30 hours

How It Connects To US8337725B2

• Both inventions are about improving battery binders for lithium-ion electrodes
  
• Each uses hydrophilic monomers to improve bonding and performance
  
• CN1328104A focuses on water-based adhesives, while US8337725B2 uses a fluorinated copolymer
  
• Both aim to make battery materials stronger, more stable, and easier to process

Why This Matters

This patent shows how water-based adhesives can make battery production safer and cleaner. It’s a useful contrast to US8337725B2, which focuses on structure and thermal stability. Both approaches move battery technology forward in different but important ways.

3. US8277976B2

This U.S. patent from LG Chemical presents a binder for lithium secondary batteries that improves both charging speed (rate performance) and battery lifespan.

The binder is water-based, environmentally friendly, and made from a mix of acrylic ester, unsaturated acid, and vinyl monomers. Its small particle size and strong adhesion help active materials stick firmly to the collector, while excellent wettability ensures better contact with the electrolyte. These properties give the battery faster ion flow, higher capacity, and longer service life. The binder also avoids the drawbacks of traditional PVDF binders that rely on toxic solvents.

These ingredients give the binder excellent adhesion and strong wettability to electrolytes, helping batteries deliver higher capacity and last longer.

What This Patent Introduces To The Landscape

1. A water-based binder system, reducing reliance on toxic solvents like NMP
   
2. Strong adhesion to both active materials and collectors, even in small amounts
   
3. Wettability that lowers the electrolyte contact angle to 40° or less, improving ion flow
   
4. Binder particle sizes between 100 and 300 nm for stable electrode structures
   
5. Proven improvement in rate performance (98%+) and cycle life (85%+ retention)

How It Connects To US8337725B2

• Both patents use hydrophilic monomers to improve binder performance.
  
• Each targets better stability and efficiency in lithium-ion batteries.
  
• US8277976B2 focuses on electrolyte interaction and long cycle life.
  
• US8337725B2 emphasizes thermal stability and random copolymer structure.
  
• Both contribute to safer, longer-lasting, and higher-performing batteries.

Why This Matters

This patent shows how fine-tuning binder chemistry can directly boost battery speed and lifespan. It complements US8337725B2 by focusing on the binder–electrolyte interface, another critical factor in building advanced lithium-ion batteries.

4. US2008166633A1

US2008166633A1 focuses on an anode design that uses a binder made from waterborne acrylic polymers combined with water-soluble polymers.

This binder provides both strong adhesion and flexibility, allowing the anode to handle the expansion and contraction that happens during charging and discharging. By holding the electrode structure together more effectively, the battery can achieve higher energy density, faster charging and discharging, and a longer lifespan.

The use of water-based binders also makes the process more environmentally friendly compared to solvent-based systems.

What This Patent Introduces To The Landscape

1. A binder system using waterborne acrylic polymers for elasticity and adhesion
   
2. Point binding between particles to improve electrode structure stability
   
3. Controlled binder particle sizes (0.1–1 μm) for effective binding
   
4. Addition of water-soluble polymers to thicken the slurry and improve the coating
   
5. Binder amounts between 1–15 parts per 100 parts active material for a balance between strength and energy density

How It Connects To US8337725B2

• Both patents focus on improving binders for lithium battery electrodes
  
• Each uses hydrophilic components to enhance bonding and stability.
  
• US2008166633A1 emphasizes elasticity and mechanical durability, while US8337725B2 emphasizes thermal stability and copolymer structure
  
• Both aim to improve battery life, performance, and manufacturing reliability.

Why This Matters

This patent shows how binder design can make batteries more durable under the stress of charging and discharging. It complements US8337725B2 by focusing on elasticity and structure, offering another path toward stronger, longer-lasting lithium batteries.

5. US2002034686A1

This patent from Zeon Corp introduces a new binder for lithium-ion battery electrodes.

This invention uses polymers based on acrylic and methacrylic acid monomers, sometimes with added crosslinking agents, to create a binder that sticks better to the electrode materials and holds up under stress. The result is a more durable electrode that maintains performance during repeated charging cycles, even at elevated temperatures of 60 °C and above.

What This Patent Introduces To The Landscape

1. A binder that improves adhesion between the active material and the collector
   
2. Electrochemical stability at both room temperature and 60°C+ conditions
   
3. Low solubility in electrolytes, with high gel content (50–100%) for durability
   
4. Use of carboxylic acid-based monomers and optional crosslinkers for strength
   
5. Slurries that include the binder, active material, and additives like cellulose derivatives

How It Connects To US8337725B2

• Both patents aim to improve binder performance in lithium-ion batteries
  
• Each uses acrylic or methacrylic chemistry to enhance adhesion and stability
  
• US2002034686A1 emphasizes high-temperature cycling and electrolyte resistance
  
• US8337725B2 emphasizes a random VDF copolymer structure for thermal and hydrophilic balance
  
• Both strengthen electrode integrity and extend battery life.

Why This Matters

This patent shows an early shift away from PVDF binders toward more advanced polymers. Its focus on adhesion and high-temperature cycling connects directly to challenges that US8337725B2 also addresses, but with a different polymer design approach.

Related Read: Discover how leaders in green hydrogen production are advancing clean energy with advanced materials, as seen in US8337725B2 and similar patents.

How To Find Similar Patents Using Global Patent Search

Exploring other inventions is useful when studying materials like US8337725B2. This patent covers fluorinated copolymers used in batteries and membranes. The Global Patent Search (GPS) tool makes it easy to discover related binder or polymer technologies and learn how they work in practice. Tools like AI-driven search platforms can also surface results based on shared chemistry or applications.

1. Enter the patent number into GPS: Start by typing US8337725B2 into the GPS tool. You can also add terms like “battery binder,” “fluorinated polymer,” or “hydrophilic membrane.”

2. Use text snippets to learn faster: GPS shows short excerpts from other patents. These explain how different binders improve adhesion, heat resistance, or electrolyte interaction.

3. Find inventions with similar features: Many results highlight copolymers with hydrophilic groups. Others focus on thermal stability or film-forming properties.

4. Compare how they solve problems: Some inventions target swelling during charge cycles. Others improve conductivity without sacrificing strength.

5. Watch for trends in polymer research: GPS helps you notice patterns, such as eco-friendly binders, higher randomization rates, or new emulsion processes.

Using Global Patent Search gives you context on where a technology fits in the landscape. It also helps you see how innovations evolve across the patent term, from filing to expiration. And because patents can become part of a patent dispute resolution, knowing similar filings gives you insight into where competition and overlap might occur.

Disclaimer: The information provided in this article is for informational purposes only and should not be considered legal advice. The related patent references mentioned are preliminary results from the Global Patent Search tool and do not guarantee legal significance. For a comprehensive related patent analysis, we recommend conducting a detailed search using GPS or consulting a patent attorney.