According to one embodiment, a secondary battery including a negative electrode. The negative electrode includes a negative electrode current collector and a negative electrode mixture layer. A thickness of the negative electrode current collector is in a range of 8 μm to 18 μm. The negative electrode current collector includes a first current collector end surface extending along a stacking direction. The negative electrode mixture layer includes a niobium-titanium composite oxide, and a first protrusion protruding from the first current collector end surface along a first direction orthogonal to the stacking direction. A protrusion length A1 of the first protrusion satisfies 0 mm