Development Trend of Electrolyte Technology in Electrochemical Energy Storage Battery

Abstract

This article delves into the development trend of electrolyte technology in electrochemical energy storage batteries, particularly focusing on lithium-ion batteries, through a comprehensive patent analysis. The study aims to provide insights into the current status, innovation process, and future directions of electrolyte technology. By leveraging patent data sourced from China’s invention patent applications, we analyze the evolution of electrolyte patents, regional competition, and key players’ strategic positioning. The findings reveal critical trends and patterns in this rapidly advancing field.

Keywords: electrochemical energy storage, electrolyte, patent analysis, development trend, lithium-ion batteries

1. Introduction

Electrochemical energy storage, exemplified by lithium-ion batteries (LIBs), has emerged as a pivotal technology in addressing the challenges of renewable energy integration and portable electronics. LIBs’ performance is significantly influenced by their constituent materials, with the electrolyte playing a crucial role in facilitating ion transport, maintaining structural integrity, and enhancing safety. Consequently, the continuous development of electrolyte technology is essential for enhancing LIBs’ performance and expanding their application scope.

This article employs patent analysis as a tool to explore the development trend of electrolyte technology in electrochemical energy storage batteries. By analyzing patent data sourced from China’s invention patent applications, we aim to provide a comprehensive understanding of the technological advancements, regional competition, and strategic positioning of key players in this field.

2. Data Sources and Methodology

2.1 Data Sources

The patent data used in this study were retrieved from the Chinese Patent Office using a combination of keywords and International Patent Classification (IPC) codes. Specifically, the keywords “lithium-ion battery,” “lithium secondary battery,” “sodium-ion battery,” “sodium secondary battery,” and their corresponding Chinese equivalents were searched in the “title/abstract/claims” fields. Additionally, the IPC codes H01M10/0566, H01M10/0567, H01M10/0568, and H01M10/0569 related to electrolyte and electrolyte composition were used to refine the search.

2.2 Methodology

The retrieved patent data were cleaned and processed to exclude irrelevant patents that focused primarily on electrodes, negative/positive active materials, and separators. The resulting dataset was analyzed using descriptive statistics, visualization tools, and content analysis methods to extract meaningful insights.

3. Analysis of Electrolyte Technology Development

3.1 Overall Development Trend

As of April 11, 2023, a total of 6,267 Chinese patent applications related to electrolyte technology in electrochemical energy storage batteries were identified. The patent application trends over time can be divided into four distinct stages, as illustrated in Figure 1.

  • Technical (1994-1999): During this early stage, only sporadic patent applications were filed, indicating the technology’s nascent development.
  • Technical (2000-2010): Patent filings gradually increased, with annual applications exceeding 100 for the first time, signifying the technology’s gradual maturation.
  • Technical (2011-2020): A surge in patent applications marked this period, particularly from 2014 to 2019, with a 212% increase in the number of filings. This reflects the technology’s rapid advancements and intensified research efforts.
  • Transition to Technological Maturity (2021-present): While the total number of patent applications declined slightly in 2021, the trend suggests a transition towards technological maturity, with a more focused and specialized research landscape.

3.2 Life Cycle Analysis

A life cycle analysis (Figure 2) further confirms the technology’s evolution. Before 2010, both patent application numbers and applicants remained low, indicative of the technology’s infancy. However, since 2010, both metrics have increased significantly, suggesting a transition from the growth stage to the maturity stage.

4. Discussion and Implications

The analysis presented in the preceding sections highlights several key trends and insights regarding the development of electrolyte technology for electrochemical energy storage batteries, particularly lithium-ion batteries.

Firstly, the evolutionary trajectory of electrolyte patents reveals a clear progression from a technical infancy stage to a period of rapid growth, and finally, towards maturity. The rapid surge in patent applications from 2011 to 2020, particularly during 2014-2019, underscores the intense R&D efforts and commercialization drive within the industry. However, the slight decline in 2021 could indicate a shift towards consolidation and refinement of existing technologies, marking the beginning of the technology maturation phase.

Secondly, the geographical distribution of patent applications indicates a significant concentration in eastern coastal provinces of China, with Guangdong, Jiangsu, and Fujian leading the way. This regional clustering could be attributed to various factors such as the presence of advanced industrial clusters, government incentives, and access to research facilities. Meanwhile, the prominence of Japanese and Korean applicants in the top-ranking list underscores the global competition in this field, with Asian nations at the forefront of innovation.

Thirdly, the patent portfolio analysis reveals a high degree of concentration among a few key players, with companies like LG, Panasonic, CATL, and BYD dominating the landscape. The significant investment in R&D by these companies reflects their commitment to staying ahead in the race for technological supremacy. Furthermore, the longevity and consistency in patent filing by some applicants, such as Sony and Mitsubishi, suggests a robust R&D strategy spanning multiple years.

The legal status of patents provides valuable insights into the commercialization potential and protection strength of various inventions. The high proportion of maintained and pending patents indicates a healthy innovation ecosystem, where companies are actively seeking to protect their intellectual property. On the other hand, the presence of a considerable number of invalidated patents highlights the challenges faced in securing valid patent protection, possibly due to issues related to novelty, inventiveness, or patentability.

Finally, the representative enterprise analysis showcases the diverse strategies employed by leading companies in advancing electrolyte technology. For instance, CATL’s extensive patent portfolio underscores its commitment to developing cutting-edge battery technologies, while Sony’s consistent filing activity over several years reflects a long-term R&D vision.

5. Conclusions

In conclusion, the development of electrolyte technology for electrochemical energy storage batteries, exemplified by lithium-ion batteries, has undergone significant evolution over the past three decades. The analysis of patent data reveals distinct trends in terms of growth patterns, geographical distribution, competitive dynamics, legal status, and corporate strategies. Key findings include:

  • A clear transition from a technical infancy stage to a period of rapid growth, culminating in a trend towards technology maturation.
  • A geographical concentration of patent applications in eastern coastal China, with significant contributions from international players.
  • A high degree of patent concentration among a select few industry leaders, underscoring the importance of R&D investment in staying competitive.
  • A mix of maintained, pending, and invalidated patents, indicating both the vitality and challenges of the innovation ecosystem.
  • Diverse corporate strategies employed by leading companies to advance electrolyte technology, with a focus on long-term R&D vision and intellectual property protection.

These insights have important implications for policymakers, researchers, and industry stakeholders, providing valuable information on the current state and future directions of electrolyte technology development for electrochemical.

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