Electrode assembly and lithium ion secondary battery using the same

A lithium ion secondary battery comprising:

• an electrode assembly including a second electrode plate, a first electrode plate, and a separator for insulating the second electrode plate from the first electrode plate;
• a can for receiving the electrode assembly;
• and
• a cap assembly including a cap plate for sealing an upper opening section of the can and an electrode terminal inserted into a terminal hole formed in the cap plate while being insulated therefrom, wherein the electrode assembly includes:
• a first electrode plate including a first surface and a second surface partially coated with a first electrode active material layer meeting a first electrode uncoated area absent the first electrode active material at a first electrode active material layer interface;
• a second electrode plate having a polarity opposite the first electrode plate and including a first surface and a second surface partially coated with a second electrode active material layer meeting a second electrode uncoated area absent the second electrode active material at a second electrode active material layer interface;
• and
• a separator for insulating the first electrode plate from the second electrode plate;
• wherein, the first electrode plate and the second electrode plate are arranged in a wound configuration such that the first electrode active material layer interface is on an innermost wind and the second electrode uncoated area is on an outermost wind and the second electrode active material layer at the second electrode active material layer interface is generally parallel to the first electrode uncoated area at the first electrode active material layer interface, and wherein the first electrode active material layer extends in a first direction at the first electrode active material layer interface and the second electrode active material layer extends in a second direction substantially opposite the first direction at the second electrode active material layer interface when the electrode assembly is viewed in a widthwise direction, such that variation of a thickness of the electrode assembly is minimized.

An electrode assembly comprising:

• a first electrode plate including a first surface and a second surface partially coated with a first electrode active material layer meeting a first electrode uncoated area absent the first electrode active material at a first electrode active material layer interface;
• a second electrode plate having a polarity opposite the first electrode plate and including a first surface and a second surface partially coated with a second electrode active material layer meeting a second electrode uncoated area absent the second electrode active material at a second electrode active material layer interface;
• and
• a separator between the first electrode plate and the second electrode plate for insulating the first electrode plate from the second electrode plate;
• wherein, the first electrode plate and the second electrode plate are arranged in a wound configuration such that the first electrode active material layer interface is on an innermost wind and the second electrode uncoated area is on an outermost wind and the second electrode active material layer at the second electrode active material layer interface is generally parallel to the first electrode uncoated area at the first electrode active material layer interface, and
• wherein the first electrode active material layer extends in a first direction at the first electrode active material layer interface and the second electrode active material layer extends in a second direction substantially opposite the first direction at the second electrode active material layer interface when the electrode assembly is viewed in a widthwise direction.