| CPC H01M 50/461 (2021.01) [H01M 50/426 (2021.01); H01M 50/446 (2021.01); H01M 50/457 (2021.01)] | 9 Claims |

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1. A battery cell, comprising:
an electrode assembly present in a battery casing,
wherein the electrode assembly comprises a positive electrode, a negative electrode and a separator interposed between the positive electrode and the negative electrode,
wherein the separator comprises a porous polymer substrate, a first organic/inorganic porous coating layer on at least one surface of the porous polymer substrate, and a second organic/inorganic porous coating layer on a surface of the first organic/inorganic porous coating layer,
wherein the first organic/inorganic porous coating layer comprises first inorganic particles and a first binder polymer,
wherein the second organic/inorganic porous coating layer comprises second inorganic particles and a second binder polymer,
wherein the second organic/inorganic porous coating layer faces the positive electrode, and
wherein the second binder polymer has a weight average molecular weight higher than a weight average molecular weight of the first binder polymer.
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