A negative-electrode core laminate of a portion of a negative-electrode core on which no negative-electrode active material layer is formed is bonded to a negative-electrode current collector by ultrasonic bonding. A core recess is formed in a bonding region of the negative-electrode core laminate bonded to the negative-electrode current collector by ultrasonic bonding, a region of the negative-electrode core laminate in which the core recess is formed includes a solid-state bonding layer and a central layer, the solid-state bonding layer being formed by solid-state bonding between layers of the negative-electrode core, the central layer being disposed between the solid-state bonding layers formed on both faces of the negative-electrode core. The average grain size of metal crystal grains constituting the solid-state bonding layer is smaller than the average grain size of metal crystal grains constituting the central layer.

A positive-electrode core laminate of a portion of a positive-electrode core on which no positive-electrode active material layer is formed is bonded to a positive-electrode current collector by ultrasonic bonding. A core recess is formed in a bonding region of the positive-electrode core laminate bonded to the positive-electrode current collector by ultrasonic bonding, a region of the positive-electrode core laminate in which the core recess is formed includes a solid-state bonding layer and a central layer, the solid-state bonding layer being formed by solid-state bonding between layers of the positive-electrode core, the central layer being disposed between the solid-state bonding layers formed on both faces of the positive-electrode core, and the first average grain size of metal crystal grains constituting the solid-state bonding layer is smaller than the second average grain size of metal crystal grains constituting the central layer.

A positive-electrode core laminate of a portion of a positive-electrode core on which no positive-electrode active material layer is formed is bonded to a positive-electrode current collector by ultrasonic bonding. A core recess is formed in a bonding region of the positive-electrode core laminate bonded to the positive-electrode current collector by ultrasonic bonding, a region of the positive-electrode core laminate in which the core recess is formed includes a solid-state bonding layer and a central layer, the solid-state bonding layer being formed by solid-state bonding between layers of the positive-electrode core, the central layer being disposed between the solid-state bonding layers formed on both faces of the positive-electrode core, and the first average grain size of metal crystal grains constituting the solid-state bonding layer is smaller than the second average grain size of metal crystal grains constituting the central layer.

An energy storage device according to one aspect of the present invention is an energy storage device including a negative electrode having a negative electrode substrate and a negative active material layer stacked on the negative electrode substrate directly or via another layer, and a nonaqueous electrolyte solution, in which the negative active material layer contains graphite and a solvent-based binder, and the negative active material layer is not subjected to pressing.

A diagnostic device for a secondary battery having a structure in which positive electrodes and negative electrodes are alternately arranged includes an electronic control unit. The electronic control unit is configured to acquire a first resistance value indicating a magnitude of electrical resistance of the secondary battery, compress at least a part of the secondary battery, acquire a second resistance value indicating a magnitude of electrical resistance of the secondary battery after the compression, determine, using the first and second resistance values, whether an amount of decrease in electrical resistance of the secondary battery by the compression is greater than a predetermined value, and determine whether an increase in resistance due to distortion of at least one of the positive electrodes and the negative electrodes occurs in the secondary battery using a result of the determination.

A diagnostic device for a secondary battery having a structure in which positive electrodes and negative electrodes are alternately arranged includes an electronic control unit. The electronic control unit is configured to acquire a first resistance value indicating a magnitude of electrical resistance of the secondary battery, compress at least a part of the secondary battery, acquire a second resistance value indicating a magnitude of electrical resistance of the secondary battery after the compression, determine, using the first and second resistance values, whether an amount of decrease in electrical resistance of the secondary battery by the compression is greater than a predetermined value, and determine whether an increase in resistance due to distortion of at least one of the positive electrodes and the negative electrodes occurs in the secondary battery using a result of the determination.

An electrochemical cell comprising a first electrode separated from a second electrode by a shutdown separator. The first electrode can comprise a first current collector substrate having a first active material composite layered thereon. The second electrode can comprise a second current collector substrate parallel to the first current collector substrate. The second current collector substrate can have a second active material composite layered thereon. The first current collector substrate can have a first current collector tab extending from the first current collector substrate at a position along an axis parallel to a plane defined by the first current collector substrate. The second current collector substrate can have a second current collector tab extending from the second current collector substrate at a same position along the axis as the first current collector tab. A battery including the electrochemical cell and methods for manufacturing the battery are also described.

The present disclosure provides a battery module, including a first battery cell arrangement structure, a second battery cell arrangement structure and a bus bar array. With battery cells stacked in a horizontal direction, a first battery cell arrangement structure and a second battery cell arrangement structure are stacked in a vertical direction, and a first bus bar of a bus bar array is used to sequentially connect the battery cells of the first battery cell arrangement structure and the second battery cell arrangement structure. As a result, a total positive electrode and a total negative electrode of a battery module are located at two ends of the battery module, which greatly reduces the possibility of a short circuit of the battery module and improves the safety of the battery module.

The present disclosure provides a battery module, including a first battery cell arrangement structure, a second battery cell arrangement structure and a bus bar array. With battery cells stacked in a horizontal direction, a first battery cell arrangement structure and a second battery cell arrangement structure are stacked in a vertical direction, and a first bus bar of a bus bar array is used to sequentially connect the battery cells of the first battery cell arrangement structure and the second battery cell arrangement structure. As a result, a total positive electrode and a total negative electrode of a battery module are located at two ends of the battery module, which greatly reduces the possibility of a short circuit of the battery module and improves the safety of the battery module.

An electrode assembly having a first electrode, a second electrode, and a separator therebetween, the first electrode, the second electrode, and the separator being wound in a jelly-roll shape is provided. The first electrode includes a first winding start portion, a first winding end portion, and a first coating portion having a first active material provided between the first winding start portion and the first winding end portion. The second electrode includes a second winding start portion, a second winding end portion, and a second coating portion having a second active material provided between the second winding start portion and the second winding end portion. A first electrode tab is provided at the first winding end portion of the first electrode. A first protective member is attached to a surface of the second winding end portion of the second electrode facing the first electrode tab.