A battery is provided. A battery according to one embodiment of the present invention comprises: an electrode assembly comprising a cathode having a cathode collector coated, partially or entirely, with a cathode active material, an anode having a nano-web layer on both sides of an anode collector coated, partially or entirely, with an anode active material, and a separation membrane interposed between the cathode and the anode; an electrolytic solution; and an exterior material which encapsulates the electrolyte solution and the electrode assembly together. According to the present invention,since the battery is provided with the porous nano-web layer, even if the temperature inside the battery increases to cause shrinkage or melting of the separation membrane, a contact between the cathode and the anode is prevented such that ignition and/or explosion of the battery does not occur, and ion exchange is not disturbed such that the battery performance does not deteriorate. In addition,the nano-web layer is not molten or released towards the separation membrane even at high temperatures. Moreover, the nano-web layer can prevent generation of cracks even when an external force is applied, and can also prevent or minimize deterioration of the physical properties required for the battery even when a repetitive external force such as repetitive vibrations, etc. is applied. As such,the battery of the present invention may be applied to various electronic devices which require flexibility of the battery, such as rollable displays, etc. as well as wearable devices such as smart watches, watch straps, etc.