Pouch exterior for secondary battery and pouch-type secondary battery comprising same
The present invention relates to a pouch exterior which can effectively block moisture penetration, and a pouch-type secondary battery comprising the same. In particular, according to the present invention, it is possible to effectively block moisture penetration between bonding interfaces at a sealing part of an upper pouch and a lower pouch. Therefore, according to the present invention it is possible to prevent the deterioration and degradation of performance of a secondary battery due to moisture penetration, and to increase stability of a secondary battery.
1. A pouch secondary battery, comprising:
an electrode assembly including a positive electrode plate, a negative electrode plate, and a separator interposed therebetween; and
a pouch packaging in which the electrode assembly and an electrolyte solution are received, the pouch packaging comprising an upper pouch and a lower pouch, the upper pouch and the lower pouch each formed by laminating an outer insulating layer, a metal layer, and an inner insulating layer in a sequential order, and the upper pouch and the lower pouch having a sealing part formed along each outer peripheral surface,
wherein the inner insulating layer includes a first moisture adsorbent material,
wherein the sealing part is coated with a finishing tape in whole or at least in part to prevent a cut surface of the sealing part from being exposed to outside,
wherein the finishing tape has an adhesive layer on one surface, and the adhesive layer includes a second moisture adsorbent material, and
wherein each of the first and second moisture adsorbent materials includes an oxazolidine-based compound represented by the following formula:
where R may be one of hydrogen (—H), a straight or branched alkyl group having 1 to 10 carbon atoms, and an aryl group, and hydrogen bonded to each carbon atom in the compounds of formulas 1 and 2 may be each independently substituted by one of a straight or branched alkyl group having 1 to 10 carbon atoms and an aryl group.
2. The pouch secondary battery according to claim 1 , wherein the first moisture adsorbent material is present in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the inner insulating layer.
3. The pouch secondary battery according to claim 1 , wherein the content of the oxazolidine-based compound in the inner insulating layer is 1000 ppm or more.
4. The pouch secondary battery according to claim 1 , wherein each of the first and second moisture adsorbent materials consists of the oxazolidine-based compound.