NOVELTY - Secondary battery (1) comprises: battery having thickness of 3-20 mm, and discharge capacity of 3-50 Ah; positive and negative electrodes with current collectors, in which active layer is formed on electrode current collector in such manner that electrode current collector exposed portion is formed, where exposed portion and width of electrode material layer satisfy specific equations; separator between electrodes that are alternately laminated; and positive (7) and negative (8) electrode tabs.    USE - As secondary battery, for battery unit or battery module (claimed) useful for portable electronic apparatus such as camera-integrated VTR (video tape recorder), cellular phone, notebook PC, and for electric automobile including hybrid electric automobile. The secondary battery is lithium ion secondary battery.    ADVANTAGE - The secondary battery, battery unit, and battery module have large current charge and discharge characteristic. The battery device has thickness of 3-20 mm, and battery discharge capacity of 3-50 Ah. When thickness of battery device is less than 3 mm, used proportion of total volume of battery device decreases, such that energy density decreases. In addition, when thickness of the battery device exceeds 20 mm, heat dissipation of battery device decreases, such that there is concern that life cycle duration during which charge and discharge is repeated may decrease. When discharge capacity is less than 3 Ah, rate characteristic is secured. Furthermore, positive electrode is formed in such manner that width of positive electrode current collector exposed portion and width of positive electrode active material layer satisfy specific equation; and negative electrode is formed in such manner that width of negative electrode current collector exposed portion and width of negative electrode active material layer satisfy specific equation, such that input and output of large current can be realized. With the battery input and output of large current is realized, such that additional high output of secondary battery can be realized. Therefore, secondary battery may be used as secondary battery for electric automobile such as hybrid electric automobile, that uses several secondary batteries which are combined to obtain high output.    DETAILED DESCRIPTION - A secondary battery (1) comprises: battery device that has thickness of 3-20 mm, and battery discharge capacity of 3-50 Ah; and exterior material (3) that packages battery device, where battery device includes, a positive electrode that has positive electrode current collector, and positive electrode active material layer, in which positive electrode active material layer is formed on positive electrode current collector in such manner that positive electrode current collector exposed portion is formed and width (wc) of positive electrode current collector exposed portion and width (Wc) of positive electrode active material layer and wc satisfy following equation of (wc divide by Wc) is greater than 0.5 to 1 (1), negative electrode that has negative electrode current collector, and negative electrode active material layer, in which negative electrode active material layer is formed on negative electrode current collector in such manner that negative electrode current collector exposed portion is formed and width (wa) of negative electrode current collector exposed portion and width (Wa) of negative electrode active material layer and wa satisfy equation of (wa divide by Wa) is greater than 0.5 to 1; separator that is interposed between positive electrode and negative electrode that are alternately laminated; positive electrode tab (7) that is electrically connected to positive electrode current collector exposed portion and is led-out to outside of exterior material; and negative electrode tab (8) that is electrically connected to negative electrode current collector exposed portion and is led-out to outside of exterior material. The positive electrode is formed in such manner that depth (dc) of positive electrode current collector exposed portion and depth (Dc) of positive electrode active material layer satisfy equation of (dc divide by Dc) is greater than 0.02 to 0.4, and negative electrode is formed in such manner that depth (da) of negative electrode current collector exposed portion and depth (Da) of negative electrode active material layer satisfy equation of (da divide by Da) is greater than 0.02 to 0.4. The positive electrode tab is formed in such manner that bonding area (Sc) between positive electrode tab and positive electrode current collector exposed portion, width (Tc) of positive electrode tab, thickness (Hc) of positive electrode tab, and thickness (B) of battery device satisfy equation of He is less than or equal to Sc divide by Tc that is less than or equal to B (5), and negative electrode tab is formed in such manner that bonding area (Sa) between negative electrode tab and negative electrode current collector exposed portion, width (Ta) of negative electrode tab, thickness (Ha) of negative electrode tab, and thickness (B) of battery device satisfy equation of Hc is less than or equal to Sa divide by Ta that is less than or equal to B. The positive electrode and negative electrode are laminated in such manner that positive electrode current collector exposed portion and negative electrode current collector exposed portion face directions different from each other. The separator is folded in zigzag fashion, and positive electrode and negative electrode are interposed between folded portions of separator, respectively. The negative electrode is interposed between pair of separators, and negative electrode and pair of separators are folded in zigzag fashion, and positive electrode is interposed between folded portions of separator. The positive electrode tab includes bent portion that is bent to follow first side surface and third side surface, and led-out portion that is led-out in direction orthogonal to third side surface, and negative electrode tab includes bent portion that is bent to follow second side surface and third side surface, and lead-out portion that is led-out in direction orthogonal to third side surface. An INDEPENDENT CLAIM is included for battery unit or battery module comprising: set of the secondary batteries; and supporting member that has outer peripheral wall portion surrounding outer periphery side surface of set of secondary batteries, where set of secondary batteries are inserted into outer peripheral wall portion from front side and rear side of supporting member, respectively.    DESCRIPTION OF DRAWING(S) - The figure shows exterior perspective view of the secondary battery.    Secondary battery (1)    Exterior packaging material (3)    Positive electrode tab (7)    Negative electrode tab (8)