Patent violation by standardization? Judge tosses Tigo lawsuit

On June 28, 2023, the U.S. District Court for the Northern District of California delivered a mixed ruling: “DENIED in part and GRANTED in part,” on the infringement claims that Tigo Energy lodged against the SunSpec Alliance.

Tigo Energy had accused the SunSpec Alliance of infringing on its patent rights by creating an industry standard for a “rapid shutdown system” for solar panels. However, the court ruled that Tigo’s three patent infringement claims were not applicable to the SunSpec Alliance or its very broad membership as a result of third parties using the standards. The rationale was that SunSpec does not manufacture the products under contention, which include inverters, optimizers and rapid shutdown devices.

However, the ruling narrowly defined two limitations. First, it is applicable exclusively to SunSpec, excluding any manufacturers of products certified by the SunSpec Alliance; this implies that such manufacturers could be found in violation if they utilize these patents. Second, SunSpec Laboratories, which produces and tests potential SunSpec-certified rapid shutdown hardware, could potentially face liability if it were proven that they had manufactured units infringing on the patent.

In a previous filing concerning 11 patents, nine were ruled in favor of Tigo, while two were in SunSpec’s favor. Included in the nine was U.S. Patent No 8,933,321, which Tigo alleged was being violated in this lawsuit.

The order outlined Tigo’s three arguments:

1. Literal infringement: Tigo asserts that SunSpec has directly infringed upon its patent by using and making the claimed system during product testing conducted by SunSpec-affiliated laboratories in accordance with the RSD (Rapid Shutdown) Specification.
2. Infringement under the Doctrine of Equivalents: Tigo argues that even if SunSpec’s actions do not literally match the patented claims, they still infringe under the doctrine of equivalents. This means that SunSpec’s actions perform substantially the same function in substantially the same way as the patented claims, resulting in infringement.
3. Induced infringement: Tigo claims that SunSpec induced infringement by actively encouraging others, including the affiliated laboratories, customers, and solar installers, to use the SunSpec RSD Specification and make, use and sell products adhering to that specification. Tigo alleges that SunSpec knew that these actions would result in infringement of the patented claims.

The court disagreed with SunSpec’s argument that it did not engage in activities that encourage infringement when it came to SunSpec’s laboratory partners. The motion points out that the plaintiff has alleged that SunSpec instructed the laboratories to perform tests using the patented technology, which can be seen as an affirmative act to induce infringement. The fact that the laboratories pay a fee to SunSpec was a key element in the argument.

In its concluding statements of the ruling, the court stated:

Tigo’s infringement claim may proceed under each of the theories of liability identified above: literal infringement, infringement under the doctrine of equivalents, and induced infringement. But those theories are only adequately pleaded as it relates to the theory that SunSpec-affiliated laboratories’ use or make the claimed systems. To the extent that the claim relies on other alleged acts by SunSpec members, customers or solar panel installers, they have not been sufficiently alleged.

The SunSpec Alliance certified product page is a “who’s who” of hundreds of hardware products that are certified under the standard from some of the industry’s largest companies.