On January 17, 2025, LONGi Green Energy Technology Co. Ltd. (“LONGi Green”) sued JinkoSolar Holding Co., Ltd. (“JinkoSolar”), Jinko Solar Co., Ltd., JinkoSolar (Vietnam) Industries Co. Ltd., and Jinko Solar Technology Sdn. Bhd. (collectively “Jinko”), alleging infringement of its photovoltaic patent U.S. Patent No. 9,515,214 (“the ’214 patent”). LONGi Green Energy Tech. Co. Ltd. v. JinkoSolar Co., Ltd., Case No. 2:25-cv-00048, Dkt. No. 1 (E.D. Tex. Jan. 17, 2025). On May 7, 2025, LONGi Green amended the complaint to add LONGi Solar Technology (U.S.) Inc. (“LONGi US”) as plaintiff. Id., Dkt. No. 36 at ¶5.
The First Amended Complaint alleges that plaintiff LONGi Green is “one of the leading manufacturers and suppliers of monocrystalline silicon solar cells and modules in the world.” LONGi, Dkt. No. 36 at ¶2. It also alleges that Plaintiff LONGi US is “the sole dealer of LONGi photovoltaic products in the United States and has an exclusive license from LONGi Green to market and sell photovoltaic products in the United States under the ’214 Patent.” Id. at ¶5.
The First Amended Complaint further alleges that JinkoSolar “claims to be one of the largest solar module manufacturers in the world” and “stated that it ‘had over 10 productions facilities globally, over 20 overseas subsidiaries . . . and a global sales network with sales teams in China [and] the United States.” LONGi, Dkt. No. 36 at ¶7.
On April 18, 2025, JinkoSolar petitioned for inter partes review of the ’214 patent. JinkoSolar Co., Ltd. v. LONGi Green Energy Tech. Co. Ltd., IPR2025-00859, Paper 1 (PTAB April 18, 2025).
The ’214 patent, titled “Solar Battery Module and Manufacturing Method Thereof,” is described as being directed to “a solar battery module that can improve an output without increasing a cross-sectional area of an interconnector.” The ’214 patent, 1:53-57.
According to the patent and as shown in the figure below, solar battery cells 20 are connected to each other in an X direction with a light-receiving surface lead 4 and a rear surface lead 7, which are band-shaped copper foil to which solder is supplied. The ’214 patent, 3:66-4:7. On the front side, silver grid electrode 13 and silver light-receiving-surface bus electrode 14 are formed on the substrate to extract electric energy. Id. at 4:60-5:1.
The ’214 patent, Fig. 5 (annotated).
According to the patent and as shown in the figure below, on the rear side, an aluminum rear-surface collecting electrode 12 and silver rear-surface bus electrode 15 are formed on the substrate to allow the rear surface lead 7 to further externally extract electric energy. The ’214 patent, 5:24-42.
The ’214 patent, Fig. 6 (annotated).
The solar battery cells have a substantially rectangular plane shape and a ratio of a short side length S and a long side length L of the rectangular is 1/2:1. The patent states that these cells can be produced by dividing conventional square-shaped solar cells into two. The ’214 patent, 4:31-43.
Further according to the ’214 patent, and as shown below, the solar battery cells 21 are serially connected to each other to form a cell string 17. An end portion of the first cell string 17A and an end portion of the second cell string 17B are joined to each other by a string connector 16, thereby forming a parallel-connected cell string 18.
The ’214 patent, Fig. 11 (annotated).
The ’214 patent alleges reduction of resistance loss and improvement of output by reducing “an electric current flowing in the interconnector that serially connects plural cells.” The ’214 patent, 2:35-39.
Claim 1 of the ’214 patent recites:
A solar battery module comprising:
a plurality of solar battery cells, a plain shape of each being a substantial rectangle, and a ratio of a short side length and a long side length of the substantial rectangle being 1/n:1 (n is an integer equal to or larger than 2), includes a plurality of light-receiving-surface bus electrodes parallel to the short side of the substantial rectangle on a light receiving surface, and includes rear-surface bus electrodes each at a position on a non-light-receiving surface corresponding to each of the light-receiving-surface bus electrodes; and
an interconnector that electrically connects the light-receiving-surface bus electrodes of a first one of the solar battery cells to the rear-surface bus electrodes of an adjacent second one of the solar battery cells, wherein a predetermined number of the solar battery cells are serially connected to each other, thereby configuring a cell string, n columns of the cell strings are connected in parallel by a first string connector at one end of the n columns, the n in the number of columns of the cell strings connected in parallel being equal to the n in the ratio of the long side length to the short side length, and the n-column parallel-connected cell strings are further serially connected to another n-column parallel-connected cell strings by a second string connector at an opposite end of the n columns, thereby configuring an entire cell array.
The ’214 patent, 11:57-12:17.
The First Amended Complaint lists no fewer than 28 of Jinko’s solar modules. LONGi, Dkt. No. 36 at ¶55. Specifically, the LONGi plaintiffs allege that Jinko’s “EAGLE, Tiger, and Cheetah brand solar modules with half-cell technology,” which the LONGi plaintiffs collectively refer to as “Jinko Half-Cell Modules,” infringe the at least claim 1 of the ’214 patent. LONGi, Dkt. No. 1-1 (Infringement Contention), 4.
For example, the LONGi plaintiffs allege that each solar battery cell in the Jinko Half-Cell Modules forms a rectangle with the short side length and the long side length being 1/2:1 in ratio.
LONGi, Dkt. No. 1-1, 4.
LONGi, Dkt. No. 1-1, 5.
The LONGi plaintiffs allege that each solar battery cell in the Jinko Half-Cell Modules includes a plurality of bus electrodes on the front and rear surface, and interconnectors that electrically connect these electrodes:
LONGi, Dkt. No. 1-1, 5 (allegedly illustrating front side bus electrodes).
LONGi, Dkt. No. 1-1, 6 (allegedly illustrating front side bus electrodes).
LONGi, Dkt. No. 1-1, 6 (allegedly illustrating rear side bus electrodes).
LONGi, Dkt. No. 1-1, 7 (allegedly illustrating rear side bus electrodes and interconnectors).
The LONGi plaintiffs also allege that in Jinko Half-Cell Modules, “a predetermined number of half-cells are serially connected to each other and configuring a cell string.” LONGi, Dkt. No. 1-1, 8.
LONGi, Dkt. No. 1-1, 9.
The LONGi plaintiffs allege that in Jinko Half-Cell Modules, “the serial connections can be seen by the interconnectors connecting the front bus electrode of the bottom left cell to the rear bus electrode of the top left cell.” LONGi, Dkt. No. 1-1, 9.
LONGi, Dkt. No. 1-1, 10.
Finally, the LONGi plaintiffs allege that the Jinko Half-Cell Modules also include cell strings connected in parallel:
LONGi, Dkt. No. 1-1, 12.
LONGi, Dkt. No. 1-1, 13.