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 at a zone referred to as a membrane zone on a main body portion of the current collector (10, 20), the electrical connection member and the current collector (10, 20) are welded and connected at a welding zone referred to as an adapting welding zone at an edge of the current collector (10, 20), and a transition zone is referred to as an extension zone (B, 512), wherein the transition zone is of the current collector (10, 20) between the membrane zone and the adapting welding zone and 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), 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; characterized in that the electrode plate further comprises a thermally conductive coating layer, and the thermally conductive coating layer covers at least a part of the electrical connection member in the adapting welding zone; 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, wherein n = 1, 2, or 3 and the width direction is a direction perpendicular to a coating direction. the electrode active material layer (11, 21) is provided at a zone referred to as a membrane zone on a main body portion of the current collector (10, 20), the electrical connection member and the current collector (10, 20) are welded and connected at a welding zone referred to as an adapting welding zone at an edge of the current collector (10, 20), and a transition zone is referred to as an extension zone (B, 512), wherein the transition zone is of the current collector (10, 20) between the membrane zone and the adapting welding zone and 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), 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; characterized in that the electrode plate further comprises a thermally conductive coating layer, and the thermally conductive coating layer covers at least a part of the electrical connection member in the adapting welding zone; 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, wherein n = 1, 2, or 3 and the width direction is a direction perpendicular to a coating direction.