Xiamen Ampack Technology Limited filed Xiamen Ampack Technology Limited v. Xiamen Hithium Energy Storage Technology Co., Ltd., No. 2:26-cv-00870, in the Marshall Division of the Eastern District of Texas on September 23, 2026, and demands a jury. Counsel are Alston & Bird LLP. Theodore Stevenson, III signed the complaint, and Brady Cox is designated lead counsel.

The parties

The complaint describes Ampack as a Chinese corporation with its principal place of business in Xiamen, Fujian. It describes Xiamen Hithium as a Chinese corporation in Xiamen. It names two other Chinese companies, Shenzhen Hithium Hero Energy Equity Technology Co., Ltd. and Chongqing Hithium Energy Storage Technology Co., Ltd., as subsidiaries or controlled companies, and four U.S. entities it calls the Hithium U.S. Entities. One of those, Hithium Tech USA Inc., is alleged to have a principal place of business in Mesquite, Texas. The complaint alleges that the foreign defendant may be sued in any district under 28 U.S.C. 1391(c).

Patents and asserted claims

The complaint brings one count per patent and says independent claim 1 of each patent is representative. It reproduces claim 1 of each patent. The prayer asks for a judgment that the defendant has infringed one or more claims of the asserted patents. The complaint alleges that Ampack owns each patent by assignment. As of September 29, 2026, USPTO assignment records showed inventor assignments of five of the six patents to Ningde Amperex Technology Limited, Dongguan Amperex Technology Limited, or both, and no recorded assignment of any of the six to Xiamen Ampack Technology Limited.

  • U.S. Patent 9,614,211, Lithium Ion Battery Having Desirable Safety Performance, issued April 4, 2017. Claim 1 is the representative claim in the complaint.
  • U.S. Patent 9,806,312, Lithium Ion Battery and Lithium Ion Battery Pack, issued October 31, 2017. Claim 1 is the representative claim.
  • U.S. Patent 10,283,816, Electrode Assembly, and Lithium Ion Electric Roll Using the Electrode Assembly, issued May 7, 2019. Claim 1 is the representative claim. Google Patents lists a priority date of December 14, 2015, and an adjusted expiration of October 26, 2036.
  • U.S. Patent 10,964,927, Separator and Electrochemical Device, issued March 30, 2021. Claim 1 is the representative claim.
  • U.S. Patent 10,964,987, Separator and Energy Storage Device, issued March 30, 2021. Claim 1 is the representative claim. Google Patents lists an adjusted expiration of September 7, 2038.
  • U.S. Patent 12,255,290, Electrode Assembly, and Lithium Ion Electric Roll Using the Electrode Assembly, issued March 18, 2025. Claim 1 is the representative claim. The complaint names the same inventors as on the '816 patent. Google Patents lists a priority date of December 14, 2015, the same priority date it lists for the '816 patent, and a certificate of correction dated April 28, 2026. The complaint's reproduction of claim 1 matches the claim as issued.

Two of the six patents have been litigated before, by Ningde Amperex Technology Limited against Zhuhai CosMX Battery Co., Ltd. In No. 2:22-cv-00232 (E.D. Tex.), the asserted claims were claims 1 and 17 of the '987 patent, claim 1 of U.S. Patent 10,833,363, and claim 1 of U.S. Patent 11,329,352. The verdict form asked one question on whether CosMX infringed claim 1 and/or claim 17 of the '987 patent, and one question on whether CosMX willfully infringed any asserted claim the jury found infringed. The amended final judgment recites that the jury found on February 9, 2024 that CosMX infringed one or more of the asserted claims, that the infringement was willful, that claims 1 and 17 of the '987 patent were not invalid, that claim 1 of the '363 patent and claim 1 of the '352 patent were invalid, and that Ningde Amperex should recover $3,701,108 for the infringement through trial. The amended final judgment of September 3, 2024, ECF No. 427, enters judgment that CosMX infringed and willfully infringed one or more of those asserted claims, that claim 1 of the '363 patent and claim 1 of the '352 patent are invalid, awards the $3,701,108, adds $1,000,000 in enhanced damages under 35 U.S.C. 284, awards an ongoing royalty of 1 percent of the agreed royalty base under the parties' stipulation, and awards $459,127 in supplemental damages and prejudgment interest. The Federal Circuit dismissed the parties' appeals, Nos. 2025-1037 and 2025-1091, under Federal Rule of Appellate Procedure 42(b) on June 9, 2026. Ningde Amperex also asserted the '927 patent against CosMX in No. 2:24-cv-00728 (E.D. Tex.). The parties reported a settlement on May 22, 2026, and filed a stipulation of dismissal on June 8, 2026.

On September 22, 2023, the Patent Trial and Appeal Board denied institution of IPR2023-00587 in Paper 12. CosMX had challenged claims 1 through 17 of the '987 patent. The Board exercised discretion under 35 U.S.C. 314(a), applying the Fintiv factors, and ordered that no trial be instituted. CosMX later petitioned for inter partes review of claims 1 through 10 of the '927 patent in IPR2025-00385. After the Acting Director declined to deny the petition on discretionary grounds and referred it to the Board on July 2, 2025, the Board denied institution on August 20, 2025, in Paper 10, finding that CosMX had not shown a reasonable likelihood of prevailing on any challenged claim. The Director denied CosMX's request for Director Review on November 3, 2025, in Paper 13. Google Patents lists a request for reexamination of the '987 patent dated May 28, 2024, with an effective date of April 4, 2024. Google Patents lists a certificate of correction for the '290 patent dated April 28, 2026.

What claim 1 of each patent covers

The summaries below restate issued claim 1 of each patent. They are not findings that Hithium practices any claim.

Claim 1 of the '211 patent covers a lithium ion battery with a battery can, a battery core received in the battery can, an electrolyte filled in the battery can, and a battery cover hermetically assembled to the battery can. The battery can or the battery cover is provided with a pressure relief valve. The pressure relief valve is coupled with a mesh cover defining a plurality of through holes. Each through hole in the mesh cover has a sectional area of 0.01 to 50 mm2.

Claim 1 of the '312 patent covers a lithium ion battery with a battery housing, a battery cover assembled to the battery housing, and a pressure relief valve coupled to the battery housing, the battery cover, or both. The housing or the cover is assembled with a first safety device fixed to the pressure relief valve. The first safety device comprises a shielding plate facing the pressure relief valve, a side wall, and an air flow channel structure. The side wall has a longitudinal axis, extends from the shielding plate, and connects with the battery housing or the battery cover. The air flow channel structure passes through the side wall along an axis perpendicular to the longitudinal axis.

Claim 1 of the '816 patent covers an electrode assembly with a bare electric roll and an anti-puncture cushion. The bare electric roll includes a top portion at a terminal side, a bottom portion at the opposite side, two first surfaces extending along a width direction and a length direction, and two second surfaces extending along a thickness direction and the length direction. The bare electric roll comprises at least one electrode unit with a cathode sheet, an anode sheet, and a separator that isolates the cathode sheet from the anode sheet. The anti-puncture cushion is arranged on each of the two second surfaces, extends to the two first surfaces, covers an edge of the anode sheet, and an edge of the cushion exceeds the bottom portion of the anode sheet.

Claim 1 of the '927 patent covers an electrochemical device with a cathode, an anode, and a separator. The separator comprises a porous substrate and a porous layer. The porous layer is disposed on a surface of the porous substrate and comprises inorganic particles and a binder. The porous substrate has an absolute plastic deformation rate in a first direction ranging from about 40 percent to about 1800 percent. That rate is calculated as (L2 minus L0) divided by L0, times 100 percent, where L0 is a length of the porous substrate before stretching and L2 is a length after the substrate is stretched to breakage, docked along the fracture, and flattened.

Claim 1 of the '987 patent covers a separator with a porous substrate and a porous layer arranged on a surface of the porous substrate. The porous layer comprises inorganic particles and a binder, and a ratio of Dv90 of the inorganic particles to the thickness of the porous layer is in a range from 0.3 to 3.0.

Claim 1 of the '290 patent covers an electrode assembly with a first electrode unit, a separator, and a first anti-puncture cushion. The first electrode unit has a first surface extending along a length direction and a width direction, a second surface opposite the first, a third surface extending along the length direction and a thickness direction, a fourth surface opposite the third, a top surface extending along the width direction and the thickness direction, and a bottom surface opposite the top. The unit comprises a first electrode sheet, a second electrode sheet, and a separator between them. Each sheet has a top edge and a bottom edge along the length direction. The first anti-puncture cushion is disposed on at least one of the third surface or the fourth surface along the width direction, and an edge of the cushion exceeds beyond at least one of the second top edge or the second bottom edge of the second electrode sheet.

Accused products and the Texas allegations

The representative product is the Hithium 314Ah Cell, which the complaint says Hithium materials identify as Cell Model LFP71173207 / 314Ah with a cell chemistry of LiFePO4. The complaint alleges that the cell's structure and operation are representative of accused products across cell, module, utility-system, commercial-and-industrial, and residential categories, plus HeroEE LIGHT, HeroEE, and LEGEND series products. Named examples include ESS Cell 314Ah, ESS Cell 280Ah-1P, ESS Module 104kWh, ARKVOLT R30, ARKVOLT F8S, ARKVOLT L16, ARKVOLT L16S, M 30, M 8 AIO, HeroEE 1, HeroEE LIGHT 1, HeroEE2, HeroEE 8 AIO, HeroEE 8, HeroEE 16, and HeroEE LEGEND 112C, along with other cell, pack, and storage-system products the complaint lists, most of them by amp-hour, kilowatt-hour, or megawatt-hour rating. Each count walks through claim 1, on information and belief, against the 314Ah cell or applicable accused products.

The complaint alleges that import records maintained by U.S. Customs and Border Protection identify importations of accused products at Houston, Long Beach, and Los Angeles. It quotes a Texas PUC filing describing a project's 150 MW battery energy storage facility as a HiTHIUM ESS 5.016MWh model with a liquid-cooled container that uses prismatic lithium iron phosphate 314Ah cells. It cites a project page identifying operating assets in McLennan County that include 184 Hithium HC 4.179 MWh containers and 92 Power Electronics FP4200M2 PCSs. It also cites Hithium's website for the proposition that the Mesquite site is one of Hithium's manufacturing bases, and a Dallas Innovates report describing a Mesquite plant as Hithium's first in North America, slated to begin mass production in late 2025. Those are allegations and quotations in the complaint.

What the complaint asks for

The nature section says Ampack asserts direct infringement and inducement and contributory infringement, under 35 U.S.C. 271(a) through (c), (f), and (g), at least for acts on or after the filing date. Each count alleges that at least as of the filing date the defendant had knowledge of the patent, and that continued direct infringement after notice of the complaint is willful. The prayer asks for a judgment of infringement of one or more claims, a judgment that post-filing and continued infringement was willful, damages of at least a reasonable royalty, enhanced damages up to treble damages, a permanent injunction or a compulsory forward royalty, an accounting, and an order finding the case exceptional with an award of attorneys' fees under section 285.

Jurisdiction, the claim charts, and an earlier trial

The complaint is a battery suit aimed at cells, modules, and installed storage systems, with the Texas link pleaded through a Mesquite address, cited project materials, and import records. The claim charts in the complaint are built on claim 1 of each patent and on one representative cell. One of the six patents, the '987 separator patent, has already been through a Marshall jury trial against a different defendant, where the jury found claims 1 and 17 not invalid, found that the defendant infringed claim 1 and/or claim 17, and found willful infringement of one or more of the asserted claims it found infringed. Expect personal jurisdiction and how far the 314Ah charts reach to be early issues.

What to watch next

Watch for service on Xiamen Hithium, its response, and whether later contentions add claims beyond claim 1.