Lithium secondary battery and secondary battery sub module comprising the same
The present invention provides a lithium secondary battery and a lithium secondary battery sub module including the same. The lithium secondary battery includes: an electrode assembly; a plastic case which houses the electrode assembly and includes a gas barrier layer; and a pouch film cover which seals the plastic case having the electrode assembly housed therein, such that it is possible to achieve a battery having a significantly increased thickness so as to increase the capacity thereof without structural limitation, secure durability of the battery due to having excellent resistance to permeability, and improve productivity due to a decrease in an occurrence of poor insulation. Thereby, the lithium secondary battery sub module including the lithium secondary battery may have a high energy density and may be formed in a compact shape with reduced manufacturing costs.
1. A lithium secondary battery sub module comprising:
a plurality of lithium secondary batteries; and
a heat radiation plate including a vertical portion disposed between two adjacent lithium secondary batteries of the plurality of lithium secondary battery,
wherein each of the plurality of lithium secondary batteries includes:
an electrode assembly;
a plastic case which is an injection molded product and housing the electrode assembly;
a gas barrier layer formed on an inner surface of the plastic case; and
a cover having a film form which seals the plastic case, the cover comprises an inner resin layer facing to the electrode assembly, an outer resin layer facing to the vertical portion of the heat radiation plate, and a metal thin film disposed between the inner resin layer and the outer resin layer,
wherein the outer resin layer formed from at least one selected from a group consisting of polyethylene terephthalate, polyethylene naphthalate, nylon and a liquid crystal polymer resin,
wherein the covers of the two adjacent lithium secondary batteries face to the vertical portion of the heat radiation plate, and the covers and the vertical portion are physically spaced apart from each other,
wherein the heat radiation plate further includes:
a first horizontal portion extending from an end of the vertical portion; and
a second horizontal portion extending from another end of the vertical portion,
wherein the two adjacent lithium secondary batteries are positioned between the first and second horizontal portion.
2. The lithium secondary battery sub module according to claim 1 , wherein the plastic case includes at least one selected from a group consisting of polyethylene, polypropylene, polyethylene terephthalate and polyethylene naphthalate.
3. The lithium secondary battery sub module according to claim 1 , wherein the gas barrier layer includes at least one selected from a group consisting of ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyvinyl alcohol, nylon, polyamide, polyacrylonitrile, linear low density polyethylene, an ethylene-vinyl alcohol copolymer, an ionomer copolymer, a metal film and a coating layer formed of at least one selected from a group consisting of silica, alumina, rubber, a metal, glass and amorphous carbon.
4. The lithium secondary battery sub module according to claim 1 , wherein the gas barrier layer includes a coating layer in which layered silicate nano particles are dispersed in a polyvinyl alcohol binder.
5. The lithium secondary battery sub module according to claim 1 , wherein each of the lithium secondary batteries further includes a plastic layer formed on an inner surface of the gas barrier layer.