An electrode plate, comprising a current collector (10, 20), an electrode active material layer (11, 21) provided on at least one surface of the current collector (10, 20), and an electrical connection member electrically connected to the current collector (10, 20), wherein the electrode active material layer (11, 21) is provided on a main body portion of the current collector (10, 20) at a zone referred to as a film zone, the electrical connection member and the current collector (10, 20) are welded and connected at an edge of the current collector (10, 20) at a welding zone referred to as an transfer welding zone, and a transition zone is referred to as an extension zone (B, 512), where the transition zone is of the current collector (10, 20) between the film zone and the transfer welding zone, and is coated with no electrode active material layer (11, 21); the current collector (10, 20) comprises a support layer (101, 201) and a conductive layer (102, 202) provided on at least one surface of the support layer (101, 201), a single-sided thickness D2 of the conductive layer (102, 202) satisfies: 30 nm ≤ D2 ≤ 3 μm, and the support layer (101, 201) is a polymer material layer or a polymer composite material layer; and a conductive primer coating layer containing a binder and a conductive material is separately provided between the current collector (10, 20) and the electrode active material layer (11, 21) in the film zone of the current collector (10, 20) and on a surface of the extension zone (B, 512) of the current collector (10, 20); and viewed in a width direction of a coated surface of the electrode plate, the electrode active material layer (11, 21) based on compacted density comprises 2n + 1 zones, and compacted density of a middle zone is greater than compacted density of zones on both sides. the electrode active material layer (11, 21) is provided on a main body portion of the current collector (10, 20) at a zone referred to as a film zone, the electrical connection member and the current collector (10, 20) are welded and connected at an edge of the current collector (10, 20) at a welding zone referred to as an transfer welding zone, and a transition zone is referred to as an extension zone (B, 512), where the transition zone is of the current collector (10, 20) between the film zone and the transfer welding zone, and is coated with no electrode active material layer (11, 21); the current collector (10, 20) comprises a support layer (101, 201) and a conductive layer (102, 202) provided on at least one surface of the support layer (101, 201), a single-sided thickness D2 of the conductive layer (102, 202) satisfies: 30 nm ≤ D2 ≤ 3 μm, and the support layer (101, 201) is a polymer material layer or a polymer composite material layer; and a conductive primer coating layer containing a binder and a conductive material is separately provided between the current collector (10, 20) and the electrode active material layer (11, 21) in the film zone of the current collector (10, 20) and on a surface of the extension zone (B, 512) of the current collector (10, 20); and viewed in a width direction of a coated surface of the electrode plate, the electrode active material layer (11, 21) based on compacted density comprises 2n + 1 zones, and compacted density of a middle zone is greater than compacted density of zones on both sides.