A battery separator, comprising a porous base membrane, and a bonding layer attached to at least one side surface of the porous base membrane, wherein the bonding layer contains an acrylate crosslinked polymer and a styrene-acrylate crosslinked copolymer but does not contain a vinylidene fluoride-hexafluoropropylene copolymer, the weight ratio of the acrylate crosslinked polymer to the styrene-acrylate crosslinked copolymer is 1:0.05 to 1:2 or the bonding layer contains an acrylate crosslinked polymer and a vinylidene fluoride-hexafluoropropylene copolymer but does not contain a styrene-acrylate crosslinked copolymer, the weight ratio of the acrylate crosslinked polymer to the vinylidene fluoride-hexafluoropropylene copolymer is 1:0.3 to 1:25 or the bonding layer contains an acrylate crosslinked polymer, a styrene-acrylate crosslinked copolymer and a vinylidene fluoride-hexafluoropropylene copolymer, the weight ratio of the acrylate crosslinked polymer to the styrene-acrylate crosslinked copolymer to the vinylidene fluoride-hexafluoropropylene copolymer is 1:(0.01 to 2):(0.3 to 5) the porosity of the bonding layer is 40-65%, wherein the acrylate crosslinked polymer is a mixture of a first acrylate crosslinked polymer and a second acrylate crosslinked polymer and/or a third acrylate crosslinked polymer, or is the second acrylate crosslinked polymer, or is the third acrylate crosslinked polymer, and wherein the first acrylate crosslinked polymer contains 70-80 wt% of polymethyl methacrylate segment, 2-10 wt% of polyethyl acrylate segment, 10-20 wt% of polybutyl acrylate segment and 2-10 wt% of polyacrylic acid segment, the second acrylate crosslinked polymer contains 30-40 wt% of polymethyl methacrylate segment, 2-10 wt% of polyethyl acrylate segment, 50-60 wt% of polybutyl acrylate segment and 2-10 wt% of polyacrylic acid segment, and the third acrylate crosslinked polymer contains 50-80 wt% of polymethyl methacrylate segment, 2-10 wt% of polyethyl acrylate segment, 15-40 wt% of polybutyl acrylate segment and 2-10 wt% of polyacrylic acid segment; a bonding layer attached to at least one side surface of the porous base membrane, wherein the bonding layer contains an acrylate crosslinked polymer and a styrene-acrylate crosslinked copolymer but does not contain a vinylidene fluoride-hexafluoropropylene copolymer, the weight ratio of the acrylate crosslinked polymer to the styrene-acrylate crosslinked copolymer is 1:0.05 to 1:2 or the bonding layer contains an acrylate crosslinked polymer, a styrene-acrylate crosslinked copolymer and a vinylidene fluoride-hexafluoropropylene copolymer, the weight ratio of the acrylate crosslinked polymer to the styrene-acrylate crosslinked copolymer to the vinylidene fluoride-hexafluoropropylene copolymer is 1:(0.01 to 2):(0.3 to 5) the porosity of the bonding layer is 40-65%, wherein the acrylate crosslinked polymer is a mixture of a first acrylate crosslinked polymer and a second acrylate crosslinked polymer and/or a third acrylate crosslinked polymer, or is the second acrylate crosslinked polymer, or is the third acrylate crosslinked polymer, and wherein the first acrylate crosslinked polymer contains 70-80 wt% of polymethyl methacrylate segment, 2-10 wt% of polyethyl acrylate segment, 10-20 wt% of polybutyl acrylate segment and 2-10 wt% of polyacrylic acid segment, the second acrylate crosslinked polymer contains 30-40 wt% of polymethyl methacrylate segment, 2-10 wt% of polyethyl acrylate segment, 50-60 wt% of polybutyl acrylate segment and 2-10 wt% of polyacrylic acid segment, and the third acrylate crosslinked polymer contains 50-80 wt% of polymethyl methacrylate segment, 2-10 wt% of polyethyl acrylate segment, 15-40 wt% of polybutyl acrylate segment and 2-10 wt% of polyacrylic acid segment; <EOS>