(19)Fresh off Patent
(45) Week of Oct 19, 2026 No. 7 3,667 lapsed 70 listed
Energy & batteries · expired at full term Oct 13, 2026

Rectangular battery pack with snap-lock metal cover

A rectangular lithium secondary battery (core pack) is housed in a plastic case body and sealed by a stainless-steel upper cover that mechanically snaps into locking grooves in the plastic case. Assembly is by elastic locking members on the metal cover that engage corresponding grooves molded in the plastic case; target users include battery module and device makers and pack assemblers.

Sheet 1 of the patent drawingsSheet 2 of the patent drawingsSheet 3 of the patent drawings

(57) What the patent covered

This write-up was generated by AI from the patent's text and may contain mistakes, so check it against the original patent before relying on it.

The independent claim covers a battery pack having: a rectangular sealed electrode/electrolyte core pack; a plastic case body with edge locking grooves; and a stainless-steel upper cover whose edge carries multiple elastic locking members each formed as a pair of locking protrusions with a spacing groove and outward tapered protrusions sized larger than the groove width so the protrusions snap into the case body grooves, thereby coupling the cover to the case body.

Distinguishing feature: Using a stainless-steel upper cover with paired elastic locking protrusions that mechanically snap into plastic case-body grooves to avoid ultrasonic welding and permit thinner packs.

Novelty 3/5. Mechanical snap-lock closure for battery packs was a known alternative to ultrasonic welding; the specific paired-protrusion geometry and stainless-steel cover for thinness is a modest improvement over common snap-fit plastic lids.

Manufacturing

Stamped/formed stainless-steel upper cover with formed elastic locking protrusions; injection-molded plastic case body with locking grooves; insertion of sealed core pack into case body and mechanical snap-assembly of cover into grooves; final electrical/thermal connections and testing.

Materials: Stainless steel (upper cover), Plastic resin for case body (e.g. PC, ABS), Electrode stack/foil materials (cathode/anode metals and separator), Electrolyte (liquid or gel).

Manufacturability 4/5. Parts are standard: one stamped/form-formed metal cover, one injection-molded plastic case; assembly is simple snap-fit but requires accurate molding and forming tolerances for reliable locking and sealing.

Market demand

Comparable products are on sale; this exact design was not found. Listings show lockable/latched lids on rectangular battery enclosures; multiple US sellers and industrial suppliers offer similar products, including metal boxes and wall-mount enclosures.

Demand check by web search, week of Oct 12, 2026. Listings change frequently.

Buyers: Battery pack assemblers, device manufacturers, EV/power-tool pack makers.

Before manufacturing

No related continuation or divisional patents in force were found. Design patents, trademarks and unrelated patents may still cover the product.

Patent lapsed; practical risks include ensuring polymer groove durability, achieving required sealing and safety certification (UL, UN 38.3) and controlling tolerances for reliable snap engagement.

This patent has reached the end of its full term and cannot be revived. This page is a research lead, not legal advice. Obtain a freedom-to-operate opinion before manufacturing.

Claim 1, as granted

1. A battery pack comprising: a rectangular core pack having an electrode group, which includes a cathode, an anode, and a separating film, and an electrolyte mounted therein in a sealed state; a case body having an inner space for receiving the core pack; and an upper cover mounted on the case body having the core pack received therein for sealing the core pack, wherein the upper case is provided at the edge thereof with a plurality of elastic locking members, and the case body is provided at the edge thereof with a plurality of locking grooves, which correspond to the locking members of the upper case, such that the locking members of the upper case are inserted into the locking grooves of the case body while the core pack is received in the case body, whereby the upper cover is coupled to the case body, wherein each of the locking members comprises a pair of locking protrusions, which are connected to each other while a spacing groove is formed between the locking protrusions, the locking protrusions are provided at the outsides thereof with protrusions, which are formed in the shape of a downward taper, each of the locking grooves has a width less than the maximum distance between the protrusions of the locking protrusions, and wherein the upper cover is made of stainless steel, and the case body is made of a plastic material, wherein the case body is made of a plastic resin at least at the areas of the case body where the locking grooves are formed, whereby the locking protrusions inserted into the locking groove penetrate into the case body adjacent to the locking groove, and the case body conforms to the locking protrusions, by a restoring force to further increase the locking force between the locking member and the locking groove.