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All-solid-state batteries are attracting attention around the world as a technology that will greatly influence the evolution of EVs (electric vehicles). This technology, which is expected to significantly improve both safety and performance compared to conventional lithium-ion batteries, is a key next-generation technology not only for the automotive industry but also for the entire energy field.
Of course, the competition for patent applications for this technology is becoming more intense every year. Not only major automobile manufacturers such as Toyota and Nissan, but also material manufacturers and start-up companies are actively seeking to retain intellectual property.
This article provides an easy-to-understand explanation from a patent attorney's perspective, from the basics of all-solid-state batteries to trends in patent applications, a comparison of major companies' strategies, and the approaches that small and medium-sized companies and startups should take.
An all-solid-state battery is a next-generation battery that replaces the conventional "liquid" electrolyte with a "solid" one. Lithium-ion batteries use liquid electrolytes using organic solvents, while all-solid-state batteries use solid electrolytes such as sulfide-based or oxide-based electrolytes.
This is expected to dramatically improve battery safety, energy density, charging speed, etc.
Three benefits of solid-state batteries
1. Dramatically improved safety
Liquid electrolytes are flammable and pose a risk of ignition or explosion upon impact or overcharging. By replacing it with a solid electrolyte, the risk of ignition is greatly reduced, greatly increasing the safety of EVs.
2. Improved energy density
Because all-solid-state batteries can use lithium metal negative electrodes, they are said to have more than double the energy density of current lithium-ion batteries. This greatly increases the cruising range of EVs.
3. Shorter charging time
Solid electrolytes can be designed with excellent ionic conductivity, and are expected to support rapid charging. If full charging can be achieved in less than 10 minutes, the convenience of EVs will improve dramatically.
In this way, all-solid-state batteries have the potential to simultaneously solve the three issues that have been the bottlenecks for the spread of EVs: safety, cruising range, and charging time. This is why governments and manufacturers around the world are making huge investments in this technology.
The number of patent applications related to solid-state batteries has been rapidly increasing since 2015. Japan in particular leads the world in the number of patent applications filed, with major companies such as Toyota, Panasonic, Nissan, Murata Manufacturing, and TDK filing for numerous patents.
The number of patent applications related to all-solid-state batteries in Japan was around 500 in 2015, reached around 1,500 in 2020, and will further increase in 2023. This rapid growth is linked to countries strengthening their EV policies and setting carbon neutrality targets.
Looking at each country, Japan remains the overwhelming leader in the number of applications, followed by South Korea and China. Although the number of applications from the US and EU is increasing, Japan and South Korea maintain a technological lead.
Analysis of the content of patent applications reveals that applications are particularly concentrated in the following technical fields.
In particular, "solid electrolyte materials" and "interface technology" have the highest number of applications, and these are fields in which companies are trying to secure intellectual property as core technologies.
Toyota and Nissan are taking different approaches in the patent race for solid-state batteries. By comparing each strategy, you can see the important ideas in patent applications.
| Comparison item | Toyota | Nissan |
|---|---|---|
| Number of applications | Over 1,000 items (top in the industry) | About 200-300 items |
| Main technical areas | Sulfide-based solid electrolyte, manufacturing process | Oxide-based solid electrolyte, cell design |
| Strategy type | Building an extensive intellectual property portfolio with a large number of applications | Concentrate investment in important technologies |
| Practical implementation goal | 2027-2028 (introduced in stages) | 2028 (mass production at once) |
| Partner collaboration | Jointly developed with Idemitsu Kosan | Technical partnership with NASA |
| Intellectual property utilization policy | Closing strategy focus (locking in own technology) | Open & closed strategy (disclosure/sharing of some technologies) |
Toyota is the world leader in the number of patent applications for solid-state batteries. A distinctive feature of this strategy is that we have acquired patents over a wide range of areas, from material technology to manufacturing processes, and even entire systems, and have built a "wall of patents" that includes areas surrounding the technology.
This increases the likelihood that competitors will run afoul of Toyota's patents if they try to make products using similar technology. This can be described as an "intellectual property fortress" strategy that takes advantage of the overwhelming resources that only a large company can have.
Nissan, on the other hand, does not match Toyota in the number of applications, but it is trying to differentiate itself with its unique approach. Of particular note are the unique material technology developed through a technical partnership with NASA and the adoption of an "open and closed strategy."
💡 What is the open & close strategy?
Our strategy is to maintain a competitive advantage by intentionally disclosing some of our own technology to promote the creation of an industry-wide ecosystem, while strictly securing the rights to our core technology (closed). Nissan is taking a balanced approach, accelerating the construction of its supply chain by exposing its fundamental technologies and differentiating itself with its unique core technologies. This strategy is also useful for small and medium-sized businesses.
As major companies file a large number of patent applications, how should small and medium-sized businesses and startups develop their patent strategies? Even with limited resources, there are ways to effectively utilize intellectual property.
✅ Point 1: Concentrate applications in niche areas
It is important to apply for patents targeting niche technology areas that are not fully covered by major companies. For example, there is room for small and medium-sized enterprises to enter into fields such as synthesis methods for specific solid electrolyte materials, unique interface treatment technologies, and battery designs for specific applications (small devices, medical equipment, etc.). Avoid a head-on collision with a major company and establish a position in a specific field as ``this company has this technology.''
✅ Point 2: Focus on patent quality
If it is not possible to file a large number of applications, it is important to focus on the quality of each patent. Strategically design your claims (patent scope) and obtain a "strong patent" that is difficult for competitors to circumvent. Claims that are too broad are likely to be rejected, and claims that are too narrow are easily avoided. The key to success is to consult closely with a patent attorney and design the optimal scope of rights.
✅ Point 3: Collaborate with license strategy
Obtained patents are a weapon for licensing. If you have a patent for a peripheral technology that a major company needs, you can use it as a bargaining chip for cross-licensing or paid licenses. Another effective approach is to develop and obtain rights to high-quality technology while keeping costs down through joint research with universities and research institutes.
⚠️ Don't forget to do the FTO (Freedom to Operate) survey!
When doing business in the solid-state battery field, an FTO investigation is essential to confirm whether your technology infringes on the patents of other companies. Particularly in this field, where major companies have built extensive patent portfolios, there is a high risk of unknowingly infringing patents, which may result in claims for damages or injunctions. We strongly recommend that an FTO investigation be conducted by a patent attorney from the early stages of product development.
Solid-state batteries are a very complex field both technologically and patent-wise. When filing a patent application in this field, it is extremely important to consult a patent attorney with expertise in both technology and law.
A patent attorney can provide support such as:
Especially for small and medium-sized enterprises and startups, utilizing the knowledge of a patent attorney who is an intellectual property expert is a shortcut to success in order to get the maximum effect with a limited budget. In order to maximize the value of your technology and ensure your competitiveness, please consult a patent attorney at an early stage.
Would you like to discuss patent strategy for solid-state batteries?
A patent attorney will analyze your company's technology and propose the optimal intellectual property strategy.
Please feel free to contact us for a free consultation.
AUTHOR
Takefumi SUGIURA （杉浦 健文）
EVORIX Intellectual Property Law Firm Managing Patent Attorney
Supports clients across IT, manufacturing, startups, fashion, and medical industries, covering patent, trademark, design, and copyright filings through trials and infringement litigation. Specialized in IP strategy for AI, IoT, Web3, and FinTech. Member of the Japan Patent Attorneys Association (JPAA), Asian Patent Attorneys Association (APAA), and Japan Trademark Association (JTA).