A lithium-ion secondary battery comprising a positive electrode plate, a negative electrode plate, a separator, and an electrolytic solution, wherein the positive electrode plate comprises a positive electrode current collector and a positive active material layer disposed on a surface of the positive electrode current collector and containing a positive active material, and the negative electrode plate comprises a negative electrode current collector and a negative active material layer disposed on a surface of the negative electrode current collector and containing a negative active material; wherein the positive active material comprises lithium iron phosphate, and the negative active material comprises graphite; wherein the positive electrode current collector and/or the negative electrode current collector are composite current collector, and the composite current collector comprises an organic support layer and a conductive layer disposed on at least one surface of the organic support layer; wherein the conductive layer has a thickness D 1 of 30 nm ≤ D 1 ≤ 3 μm, and the organic support layer has a thickness D 2 of 1 μm ≤ D 2 ≤ 30 μm; wherein the positive active material layer has a thickness T 1 satisfying 50 μm ≤ T 1 ≤ 100 μm, and the negative active material layer has a thickness T 2 satisfying 30 μm ≤ T2 ≤ 70 μm; wherein the conductive layer comprises one or more of metal material, carbon-based conductive material and conductive polymer material, and the organic support layer comprises one or more of polymer material and polymer-based composite material, wherein the polymer material is one or more of polyamide, polyimide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, poly(propylene-ethylene), acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, poly vinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyoxymethylene, polyphenylene oxide, polyphenylene sulfide, polyethylene glycol, polysulfur nitride, polyphenylene, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, phenolic resin, the derivatives thereof, the cross-linked products thereof, and the copolymers thereof, and wherein the polymer-based composite material comprises the polymer material and an additive comprising one or more of metallic materials and inorganic nonmetallic materials; and wherein the composite current collector has a thermal conductivity of 0.01 W/(m•K) to 10 W/(m•K), measured according to the methods as described in the description. wherein the positive active material comprises lithium iron phosphate, and the negative active material comprises graphite; wherein the positive electrode current collector and/or the negative electrode current collector are composite current collector, and the composite current collector comprises an organic support layer and a conductive layer disposed on at least one surface of the organic support layer; wherein the conductive layer has a thickness D 1 of 30 nm ≤ D 1 ≤ 3 μm, and the organic support layer has a thickness D 2 of 1 μm ≤ D 2 ≤ 30 μm; wherein the positive active material layer has a thickness T 1 satisfying 50 μm ≤ T 1 ≤ 100 μm, and the negative active material layer has a thickness T 2 satisfying 30 μm ≤ T2 ≤ 70 μm; wherein the conductive layer comprises one or more of metal material, carbon-based conductive material and conductive polymer material, and the organic support layer comprises one or more of polymer material and polymer-based composite material, wherein the polymer material is one or more of polyamide, polyimide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, poly(propylene-ethylene), acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, poly vinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyoxymethylene, polyphenylene oxide, polyphenylene sulfide, polyethylene glycol, polysulfur nitride, polyphenylene, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, phenolic resin, the derivatives thereof, the cross-linked products thereof, and the copolymers thereof, and wherein the polymer-based composite material comprises the polymer material and an additive comprising one or more of metallic materials and inorganic nonmetallic materials; and wherein the composite current collector has a thermal conductivity of 0.01 W/(m•K) to 10 W/(m•K), measured according to the methods as described in the description.