NOVELTY - The battery pack (40) comprises a non-aqueous electrolyte secondary battery including a battery element with a positive electrode, a negative electrode and a separator that are spirally wound or stacked and a flexible covering member. The separator is disposed between the positive electrode and the negative electrode. The battery element includes a non-aqueous electrolyte composition. The flexible covering member is formed of a first laminated film, and covers a principal portion of the battery element. The first laminated film is composed of a first heat-bonding layer.    USE - The battery pack having non-aqueous electrolyte secondary battery e.g. lithium-ion secondary battery is useful for portable electronic devices such as videotape recorders (VTRs) with camera, cell phones, and laptop computers.    ADVANTAGE - The battery pack has improved resistance, improved reliability or safety and excellent volume efficiency, is capable of resisting deformation or the like when it suffers an impact/shock of short drop, and avoids the breakage of the portable electric device on which it is connected using flexible covering member.    DETAILED DESCRIPTION - The battery pack (40) comprises a non-aqueous electrolyte secondary battery including a battery element with a positive electrode, a negative electrode and a separator that are spirally wound or stacked and a flexible covering member. The separator is disposed between the positive electrode and the negative electrode. The battery element includes a non-aqueous electrolyte composition. The flexible covering member is formed of a first laminated film, and covers a principal portion of the battery element. The first laminated film is composed of a first heat-bonding layer, a first metal layer, and a first outer covering layer that are laminated successively. The flexible covering member is sealed along around the battery element while leaving electrode terminals of the positive and negative electrodes extended outside the battery element. A rigid covering member is arranged with the flexible covering member for covering the non-aqueous electrolyte secondary battery, and is formed of a second laminated film composed of a second heat-bonding layer, a second metal layer and a second outer covering layer that are laminated successively. A protection circuit board is housed in the rigid covering member for controlling a voltage and a current of the non-aqueous electrolyte secondary battery. The battery element and the flexible covering member adhere to each other. The flexible covering member and the rigid covering member are thermally fused, and bonded with an adhesive strength ( greater than or equal to 0.1 MPa) equal to or higher than atmospheric pressure and with a peel strength ( less than or equal to 5 N/mm) equal to or lower than a breaking strength of the flexible covering member. The first outer covering layer has a thermal conductivity of less than or equal to 1 and a melting temperature higher than that of the second heat-bonding layer. A laminated layer of the second outer covering layer and the second metal layer has a thermal conductivity of greater than or equal to 1000 Wm-2K-1 per area. The rigid covering member is formed of a combination of the second metal layer having a thermal conductivity of greater than or equal to 50000 Wm-2K-1 per area and the second outer covering layer having a thermal conductivity of greater than or equal to 1050 Wm-2K-1 per area. The second metal layer has a thickness of less than or equal to 330 mu m. The second outer covering layer has a thickness of less than or equal to 115 mu m.    DESCRIPTION OF DRAWING(S) - The figure shows a perspective view of a battery pack.    Battery pack (40)    Rigid laminated film (41)    Top cover (42)    Rear cover (43)    Product label. (46)