Electrochemical device having spiral wound electrodes

An apparatus for applying pressure against a roll having a pair of elongated electrodes, each supported in one of two alternating folds of a separator layer, and spirally wound in the roll with said separator layer about a central axis to define two opposing ends, each only exposing a different one of the electrodes wound along the roll, said apparatus comprising:

• a housing having a top wall and a bottom wall;
• said top wall providing a first member having a first planar surface disposed along a first of said two opposing ends of said roll to face a first different one of the exposed electrodes;
• a second member within said housing having a second planar surface disposed along a second of said two opposing ends of said roll to face a second different one of the exposed electrodes, in which said second member is generally perpendicular to said electrodes along their respective length;
• said bottom wall providing a third member non-adjustably fixable in position with respect to said first member with at least said roll and said second member between said first member and said third member;
• and
• a fourth member within said housing between said second member and said third member, said fourth member providing spring elements, each of said spring elements being a bent prong from material of said fourth member to a foot disposed against said third member, said spring elements being compressible to enable said fourth member to apply pressure to force said second member toward said first member in a direction generally parallel to said central axis promoting contact of said first planar surface and said second planar surface with said first and said second different one of the exposed electrodes, respectively, to provide one or more of reduced electrical and thermal resistance.

An electrochemical device comprising:

• a positive electrode strip, a negative electrode strip, and a separator layer spirally wound in a roll around a central axis in which said separator layer is disposed to prevent direct contact between said positive electrode strip and said negative electrode strip, wherein said positive electrode strip and said negative electrode strip each have a length with a first edge and a second edge opposing the first edge along said length in said roll;
• a housing having a top wall and a bottom wall;
• said top wall having a first planar surface perpendicular to said central axis;
• a member within said housing having a second planar surface perpendicular to said central axis and facing said first planar surface;
• said separator layer being of a zig zag shape to provide a first fold portion supporting said positive electrode strip and the second edge thereof and a second fold portion supporting said negative electrode strip and the second edge thereof, in which, along said roll, a portion of each of said positive electrode strip and said negative electrode strip exits from said first fold portion and said second fold portion, respectively, beyond said separator layer in one of two opposite directions generally parallel with said central axis to dispose said first edge of said positive electrode strip and said first edge of negative electrode strip to each face a different one of said top wall and said member, wherein said member is generally perpendicular to said positive electrode strip and said negative electrode strip along their respective said length;
• a plurality of spring elements disposed with said member between said roll and said bottom wall, said spring elements being compressible with respect to said bottom wall to enable said member to apply pressure upon said roll toward said first planar surface in order to position said first edge of said positive electrode strip and said first edge of said negative electrode strip in contact against their respective facing said different one of said first planar surface and said second planar surface;
• said housing further comprises a first housing portion with a generally cylindrical side wall extending from said top wall downward to a lower edge, and a second housing portion with a generally cylindrical side wall extending upward from said bottom wall, and said first and second housing portions being disposed such that said lower edge faces said bottom wall and said side wall of said second housing portion at least partially overlaps said side wall of said first housing portion to define a gap therebetween;
• non-conductive sealing material disposed between said lower edge of said first housing portion and said bottom wall, and along said gap to seal said housing closed;
• and
• said first and second housing portions being non-adjustably fixed with respect to each other with said spring elements maintaining a contact pressure of said first edge of said positive electrode strip and said first edge of said negative electrode strip against their respective facing of said different ones of said first planar surface and said second planar surface which minimizes electrical contact resistance during operation of said device.