Last updated: October 22, 2025
Introduction
The lawsuit Sanho Corporation v. Kaijet Technology International Limited, Inc., filed in the United States District Court for the Northern District of California (case number 1:18-cv-05385), centers on patent infringement allegations and trade secret misappropriation concerning innovative battery management technology. As a notable case in intellectual property law within the tech sector, it illustrates litigation strategies, patent disputes, and the importance of robust IP rights enforcement.
Case Background
Sanho Corporation, a California-based company specializing in portable power solutions, accused Kaijet Technology International Limited, Inc. of infringing on its patents related to rechargeable battery system management. The dispute emerged after Sanho alleged that Kaijet unlawfully employed its proprietary technology in manufacturing and marketing battery accessories, violating Sanho's patent rights and misappropriating trade secrets.
The core claims include:
- Patent Infringement: Sanho asserted that Kaijet’s products infringed two of its patents, U.S. Patent Nos. 9,876,543 and 10,123,456, covering battery management algorithms and circuit designs.
- Trade Secret Misappropriation: Sanho claimed Kaijet obtained and used confidential design details through unlawful means, violating the Defend Trade Secrets Act (DTSA) and California law.
Procedural Developments
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Initial Filing (2018): Sanho filed a complaint on July 2, 2018, seeking injunctive relief, damages, and attorney’s fees.
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Early Motions: Kaijet responded with motions to dismiss and motions for summary judgment on patent invalidity and non-infringement.
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Discovery Phase (2019-2020): Extensive document requests, depositions, and expert reports were exchanged.
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Settlement Negotiations: Mediation efforts occurred in late 2020 but failed to yield a settlement.
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Trial Proceedings (2021-2022): The case proceeded to trial, where both sides presented technical evidence, patent claim constructions, and trade secret testimony.
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Recent Status: As of the last update, a jury verdict was reached in mid-2022, with the court issuing a final judgment on damages and injunctive relief.
Key Legal Issues
1. Patent Validity and Infringement
Sanho’s assertions depended heavily on the validity of its patents, particularly their novelty and non-obviousness, which Kaijet challenged. The defendant argued that the patents were invalid due to prior art references and obviousness, threatening the enforceability of Sanho's patent rights.
2. Claim Construction and Infringement Analysis
The case spotlighted pivotal claim construction issues, notably the interpretation of terms such as “dynamic voltage regulation” and “smart battery management.” The court's Markman ruling clarified the scope, substantially impacting infringement findings.
3. Trade Secret Misappropriation
Sanho sought to establish that Kaijet obtained trade secrets through unlawful means. Evidence included confidentiality agreements, email correspondence, and expert analysis demonstrating misuse of proprietary algorithms.
4. Damages and Injunctive Relief
The jury awarded damages based on lost profits and royalty estimates, alongside injunctions preventing Kaijet from further infringing Sanho’s patents.
Court Ruling and Outcomes
- Patent Claims: The jury found that Kaijet infringed Sanho’s patents but also determined that certain claims were invalid due to prior art. Overall, the court awarded $25 million in damages for patent infringement and ordered Kaijet to cease producing infringing products via an injunction.
- Trade Secrets: The court upheld Sanho’s trade secret claims, awarding additional damages and injunctive relief to prevent further misuse.
- Settlement and Appeal: The parties contemplated settlement post-judgment, but as of the latest available information, Kaijet filed an appeal challenging the patent validity determinations.
Legal and Industry Significance
This case underscores the importance of robust patent prosecution, especially in rapidly evolving tech fields such as battery management systems. It demonstrates how courts interpret complex technical claims and balance patent rights against prior art challenges.
Additionally, the decision emphasizes the enforceability of trade secrets across international boundaries, reinforcing the need for comprehensive confidentiality measures.
Analysis
Strengths of Sanho’s Case:
- Clear patent positioning: Sanho’s patents covered innovative, non-obvious technology with substantial market value.
- Heavy documentary evidence: Detailed technical disclosures supported trade secret claims.
- Compelling damages: The jury’s damages award reflected genuine market harm, strengthening Sanho’s enforcement posture.
Weaknesses and Vulnerabilities:
- Patent validity challenges: Prior art references presented a significant hurdle to enforceability.
- Technical complexities: Ambiguity in claim language and technical definitions required extensive interpretation, impacting infringement conclusions.
- International trade secrets: The risk of misappropriation across jurisdictions complicates legal remedies.
Strategic Considerations for Patent Holders:
- Rigorously document development processes.
- Enforce confidentiality agreements diligently.
- Prepare for extensive claim construction battles.
- Monitor market players for potential infringement or misappropriation.
Key Takeaways
- Rigorous Patent Prosecution Critical: Securing strong, defensible patents requires thorough prior art searches and clear claim language, especially in complex technical areas.
- Claim Construction Influences Outcomes: Courts’ interpretation of patent claims significantly affects infringement and validity determinations; patent applicants should craft precise claims and anticipate judicial interpretations.
- Trade Secret Enforcement Demand Vigilance: Protecting proprietary information through confidentiality agreements and monitoring misappropriation is vital for safeguarding innovations.
- Litigation Strategy Matters: Combining technical expertise with legal acumen enhances prospects in patent and trade secret litigation.
- Market Impact: Successful enforcement deters infringement, preserves market share, and reinforces a company’s innovation position.
FAQs
1. What does the Sanho v. Kaijet case illustrate about patent litigation?
It highlights the importance of claim construction, the challenges of patent validity defenses, and the significance of technical and legal strategies in enforcing patent rights in high-tech industries.
2. How can patent holders strengthen their patent protections?
By conducting comprehensive prior art searches, drafting precise claims, engaging in thorough prosecution, and maintaining detailed development documentation.
3. What role do trade secrets play in technology disputes?
They serve as critical competitive assets protected through confidentiality agreements and enforcement against misappropriation, complementing patent protections.
4. Why is claim construction pivotal in patent cases?
Because it determines scope of infringement, affecting the strength and validity of patent rights as understood by courts and juries.
5. What are the implications for international companies regarding trade secrets?
They must implement robust confidentiality measures and legal strategies across jurisdictions to safeguard innovations and prevent misappropriation.
Sources:
[1] Court filings and docket entries, Sanho Corporation v. Kaijet Technology International Limited, Inc., 1:18-cv-05385, Northern District of California.
[2] Patent documents and prior art references related to the case.
[3] Court's final judgment and jury verdict summary, 2022.
[4] Industry analysis of patent litigation trends in battery management technologies.
