Search

EP-4178010-B1 - BATTERY CELL STACK AND MANUFACTURING METHOD THEREOF

EP4178010B1EP 4178010 B1EP4178010 B1EP 4178010B1EP-4178010-B1

Inventors

  • RHEE, SEO ROH
  • KIM, JI SAN
  • PARK, CHI MIN
  • YOO, TAK KYUNG

Dates

Publication Date
20260513
Application Date
20221108

Claims (10)

  1. A battery cell stack (100) comprising: a plurality of battery cells (110); and a resin layer (120) which is wholly or partially in contact with an outer surface of at least one of the plurality of battery cells (110), wherein the resin layer (120) includes a solvent-free adhesive, and has a peel strength of 1,000 gf/in to 3,000 gf/in (3.86N/cm to 11.58 N/cm) measured according to ASTM D3330 and as disclosed in the description, and a shear strength of 20 kgf/sq-in to 100 kgf/sq-in (30.40 N/cm 2 to 152.00 N/cm 2 ) measured according to ASTM D1002 and as disclosed in the description, and wherein the solvent-free adhesive is a pressure sensitive adhesive (PSA).
  2. The battery cell stack (100) according to claim 1, wherein the solvent-free adhesive includes one or more selected from the group consisting of an ethylene vinyl acetate resin, polyamide resin, fatty acid polyamide resin, polyester resin, polyurethane resin, polyolefin resin, styrene resin and rubber resin.
  3. The battery cell stack (100) according to claim 1 or 2, wherein the resin layer (120) has a softening point of 60.0 °C to 140.0 °C.
  4. The battery cell stack (100) according to anyone of the preceding claims, wherein the resin layer (120) has a withstand voltage of 10.0 kV/mm to 30.0 kV/mm measured according to ASTM D149 and as disclosed in the description.
  5. The battery cell stack (100) according to anyone of the preceding claims, wherein the battery cell stack (100) further comprises a functional layer disposed between the plurality of battery cells (110), and the resin layer (120) is wholly or partially in contact with the functional layer (130).
  6. The battery cell stack (100) according to claim 5, wherein the functional layer (130) includes one or more selected from the group consisting of aerogel, talc, kaolin, alumina, feldspar, pyrophyllite, sericite, mica, elvan, bentonite, sepiolite, diatomite, perlite, fumed silica, silica, glass bubble, glass bead, magnesium hydroxide, calcium carbide, glass fibers, glass wool, rock wool, ceramic wool, nylon, aramid fibers, carbon fibers, polypropylene fibers, polyethylene fibers, polyester fibers, polyurethane fibers, acrylic fibers, polyvinyl chloride acetate fibers, and rayon fibers.
  7. A method of manufacturing a battery cell stack (100) as defined in claim 1, the method comprising: applying a resin layer (120), which includes a solvent-free adhesive and has a peel strength of 1,000 gf/in to 3,000 gf/in (3.86N/cm to 11.58 N/cm) measured according to ASTM D3330 and as disclosed in the description, and a shear strength of 20 kgf/sq-in to 100 kgf/sq-in (30.40 N/cm 2 to 152.00 N/cm 2 ) measured according to ASTM D1002 and as disclosed in the description, to an outer surface of a battery cell (110) so as to bring it wholly or partially into contact therewith; and stacking an additional battery cell (110) on the resin layer (120), and wherein the solvent-free adhesive is a pressure sensitive adhesive (PSA).
  8. The method according to claim 7, wherein the resin layer (120) is applied by spray coating or slot die coating.
  9. The method according to claim 7 or 8, wherein the application of the resin layer (120) is performed at 140 °C to 180 °C.
  10. The method according to anyone of claims 7 to 9, wherein the resin layer (120) has a thickness of 0.01 to 0.10 mm.

Description

[BACKGROUND OF THE INVENTION] 1. Field of the Invention The present invention relates to a battery cell stack and a method of manufacturing the same. 2. Description of the Related Art Research into a rechargeable secondary battery capable of being charged and discharged has been actively conducted in accordance with the development of state-of-the-art fields such as a digital camera, a cellular phone, a laptop computer, a hybrid automobile and the like. Examples of the secondary battery may include a nickel-cadmium battery, a nickel-metal hydride battery, a nickel-hydrogen battery, and a lithium secondary battery. Among them, since the lithium secondary batteries have a high operating voltage and excellent energy density characteristics per unit weight, they are used as a power source for portable electronic devices. Alternately, a plurality of lithium secondary batteries are connected in series, and then used in a high-output hybrid vehicle or an electric vehicle. When used in the high-output hybrid vehicle or electric vehicle, in order to increase capacity and output of the secondary battery, a plurality of secondary batteries may be connected and used in a form of one battery module and a battery pack. In order to configure the above-described battery module or battery pack, various fastening parts or cooling equipment are required. However, these fastening parts or cooling equipment cause an increase in manufacturing costs while increasing volume and weight thereof, and also lead to a decrease in output in proportion to the increased volume and weight. A method of manufacturing a cell stack forming a battery module by attaching a tape type adhesive to cell surfaces is also used. However, processes and equipment for inputting the tape and removing a release paper are complicated, and waste such as release paper may be generated in large quantities during manufacturing the battery module. In addition, when the tape is incorrectly attached due to an error in the process or a difference in flatness of the cell surface, it is difficult to perform a rework on the tape and reuse thereof. Korean Patent Publication No. 10-2020-0002349(Family Patent of US 2020/0006726 A1) discloses a battery module including a unit sheet coated with a polymer resin on the outside, and Korean Patent Publication No. 10-2021-0020665 discloses a battery module including a resin composition satisfying specific values of physical properties such as thickness, length, and elongation. Efforts have been made to improve a battery module manufacturing process by adjusting the physical properties of the resin (e.g., shear strength, peel strength, tensile strength, thermal conductivity, etc). However, among the above physical properties, if at least one of peel strength and shear strength is not included in a specific range, reworkability is lower or the manufactured laminate is unstable. [Prior Art Documents] [Patent Documents] Korean Patent Laid-Open Publication No. 10-2020-0002349Korean Patent Laid-Open Publication No. 10-2021-0020665 [SUMMARY OF THE INVENTION] An object of embodiments of the present invention is to provide a battery cell stack, to which a resin layer including a solvent-free adhesive suitable for improving structural stability, reliability and reworkability is applied, while simplifying materials and processes necessary to manufacture the cell stack, and a method of manufacturing the same. To achieve the above object, according to an aspect of the present invention, there is provided a battery cell stack including: a plurality of battery cells; and a resin layer which is wholly or partially in contact with an outer surface of at least one of the plurality of battery cells. The scope of the invention is defined by the appended claims. The resin layer is formed of a resin layer composition including a solvent-free adhesive. The resin layer has peel strength of 1,000 gf/in to 3,000 gf/in (3.86N/cm to 11.58 N/cm) measured according to ASTM D3330. The resin layer has a shear strength of 20 kgf/sq-in to 100 kgf/sq-in (30.40 N/cm2 to 152.00 N/cm2) measured according to ASTM D1002. In some embodiments, the solvent-free adhesive may include one or more selected from the group consisting of an ethylene vinyl acetate resin, polyamide resin, fatty acid polyamide resin, polyester resin, polyurethane resin, polyolefin resin, styrene resin and rubber resin. The solvent-free adhesive is a pressure sensitive adhesive (PSA). In some embodiments, the resin layer may have a viscosity of 2,000 cps to 18,500 cps at 160 °C. In some embodiments, the resin layer may have a softening point of 60 °C to 140 °C. In some embodiments, the resin layer may have a withstand voltage of 10.0 to 30.0 kV/mm measured according to ASTM D149. In some embodiments, the battery cell stack may further include a functional layer disposed between the plurality of battery cells, and the resin layer may be wholly or partially in contact with the functional layer. In som