대표
청구항
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1. A nonaqueous electrolyte secondary battery comprising: a flat winding electrode assembly formed by winding a positive electrode having a rectangular shape and a negative electrode having a rectangular shape with a separator having a rectangular shape and being interposed therebetween; andan outer body storing the flat winding electrode assembly and a nonaqueous electrolyte,the flat winding electrode assembly including a positive electrode substrate exposed portion wound on one end and a negative electrode substrate exposed portion wound on the other e...
1. A nonaqueous electrolyte secondary battery comprising: a flat winding electrode assembly formed by winding a positive electrode having a rectangular shape and a negative electrode having a rectangular shape with a separator having a rectangular shape and being interposed therebetween; andan outer body storing the flat winding electrode assembly and a nonaqueous electrolyte,the flat winding electrode assembly including a positive electrode substrate exposed portion wound on one end and a negative electrode substrate exposed portion wound on the other end,the positive electrode substrate exposed portion having a melting area of 2.7 mm2 or more in a plane passing through a central axis of a welded connection portion and being perpendicular to a winding axis of the winding electrode assembly within the welded connection portion with a positive electrode collector,the negative electrode substrate exposed portion having a melting area of 1.8 mm2 or more in a plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with a negative electrode collector,the melting area of the positive electrode substrate exposed portion being greater than the melting area of the negative electrode substrate exposed portion,the winding number of the wound positive electrode substrate exposed portion being 30 or more, and the winding number of the wound negative electrode substrate exposed portion being 30 or more,the wound positive electrode substrate exposed portion having an outermost surface welded and connected with the positive electrode collector, and the wound negative electrode substrate exposed portion having an outermost surface welded and connected with the negative electrode collector,the nonaqueous electrolyte containing a lithium salt having an oxalate complex as an anion at the time of making the nonaqueous electrolyte second battery,all of the layers of the positive electrode substrate exposed portion being melted at the welded connection portion between the positive electrode substrate exposed portion and the positive electrode collector to be welded and connected to the positive electrode collector,all of the layers of the negative electrode substrate exposed portion being melted at the welded connection portion between the negative electrode substrate exposed portion and the negative electrode collector to be welded and connected to the negative electrode collector,the positive electrode collector is formed by using aluminum or an aluminum alloy,the positive electrode substrate exposed portion is formed by using aluminum or an aluminum alloy,the negative electrode collector is formed by using copper or a copper alloy, andthe negative electrode substrate exposed portion is formed by using copper or a copper alloy. 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein the welded connection portion between the positive electrode substrate exposed portion and the positive electrode collector is provided at least at one point on each of both sides across the winding central position of the flat winding electrode assembly, andthe welded connection portion between the negative electrode substrate exposed portion and the negative electrode collector is provided at least at one point on each of both sides across the winding central position of the flat winding electrode assembly. 3. The nonaqueous electrolyte secondary battery according to claim 1, wherein the wound positive electrode substrate exposed portion and the wound negative electrode substrate exposed portion are each divided into two segments,the two segments of the wound positive electrode substrate exposed portion are disposed so that a positive electrode conductive member is arranged therebetween,the two segments of the wound negative electrode substrate exposed portion are disposed so that a negative electrode conductive member is arranged therebetween, andthe melting area of the positive electrode substrate exposed portion in the plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with the positive electrode collector is smaller than a cross-sectional area of the positive electrode conductive member in the plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with the positive electrode collector. 4. The nonaqueous electrolyte secondary battery according to claim 1, wherein the lithium salt having the oxalate complex as an anion is contained in an amount of 0.01 to 2.0 mol/L at the time of making the nonaqueous electrolyte secondary battery. 5. The nonaqueous electrolyte secondary battery according to claim 1, wherein the lithium salt having the oxalate complex as an anion is lithium bis(oxalato)borate (Li[B(C2O4)2]). 6. The nonaqueous electrolyte secondary battery according to claim 1, wherein the nonaqueous electrolyte containing lithium difluorophosphate (LiPF2O2) at the time of making the nonaqueous electrolyte secondary battery. 7. The nonaqueous electrolyte secondary battery according to claim 1, wherein a prismatic outer body having an opening portion and a bottom, storing the winding electrode assembly;a sealing plate sealing the opening portion; anda rib, whereinthe positive electrode collector includes a first region, a second region, a third region, a fourth region, a first bent portion, and second bent portion,the first region is disposed between the sealing plate and the winding electrode assembly,the first region is disposed substantially parallel to the sealing plate,the second region extends from an end of the sealing plate toward the bottom,the fourth region is disposed on an outer surface of the positive electrode substrate exposed portion,the third region connects between the second region and the fourth region,the first bent portion is formed at a boundary between the second region and the third region,the second bent portion is formed at a boundary between the third region and the fourth region,the melting area of the positive electrode substrate exposed portion in the plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with the positive electrode collector is smaller than a projected area of the rib onto a plane perpendicular to the winding axis of the winding electrode assembly by projecting in the direction of the winding axis of the winding electrode assembly, andthe rib is provided on an end on the center side of the flat winding electrode assembly of the fourth region and is substantially perpendicular to the fourth region. 8. The nonaqueous electrolyte secondary battery according to claim 1, wherein the nonaqueous electrolyte contains a lithium salt having an oxalate complex as an anion. 9. The nonaqueous electrolyte secondary battery according to claim 6, wherein the nonaqueous electrolyte contains lithium difluorophosphate (LiPF2O2). 10. The nonaqueous electrolyte secondary battery according to claim 1, further comprising: a prismatic outer body having an opening portion, storing the winding electrode assembly;a sealing plate sealing the opening portion; anda rib, whereinthe positive electrode collector includes a first region, a second region, a third region, a fourth region, a first bent portion, and second bent portion,the first region is disposed between the sealing plate and the winding electrode assembly,the first region is disposed substantially parallel to the sealing plate,the second region extends from an end of the sealing plate toward the bottom,the fourth region is disposed on an outer surface of the positive electrode substrate exposed portion,the third region connects between the second region and the fourth region, the first bent portion is formed at a boundary between the second region and the third region,the second bent portion is formed at a boundary between the third region and the fourth region,the melting area of the positive electrode substrate exposed portion in the plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with the positive electrode collector has a length in a direction perpendicular to the sealing plate shorter than that of the rib in the direction perpendicular to the sealing plate, andthe rib is provided on an end on the center side of the flat winding electrode assembly of the fourth region and is substantially perpendicular to the fourth region. 11. The nonaqueous electrolyte secondary battery according to claim 1, further comprising: a prismatic outer body having an opening portion and a bottom, storing the winding electrode assembly;a sealing plate sealing the opening portion; andat least one rib, whereinthe positive electrode collector includes a first region, a second region, a third region, a fourth region, a first bent portion, and second bent portion,the first region is disposed between the sealing plate and the winding electrode assembly,the first region is disposed substantially parallel to the sealing plate,the second region extends from an end of the sealing plate toward the bottom,the fourth region is disposed on an outer surface of the positive electrode substrate exposed portion,the third region connects between the second region and the fourth region,the first bent portion is formed at a boundary between the second region and the third region,the second bent portion is formed at a boundary between the third region and the fourth region,the melting area of the positive electrode substrate exposed portion in the plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with the positive electrode collector has a length in a direction perpendicular to the sealing plate shorter than that of the second region in the direction perpendicular to the sealing plate, andthe rib is provided on an end on the center side of the flat winding electrode assembly of the fourth region and is substantially perpendicular to the fourth region, the length of the rib in a direction perpendicular to the sealing plate is smaller than the length of fourth region in the direction perpendicular to the sealing plate. 12. The nonaqueous electrolyte secondary battery according to claim 1, wherein the welded connection portion of the positive electrode and the welded connection portion of the negative electrode have mechanical strength substantially equivalent to each other. 13. A nonaqueous electrolyte secondary battery comprising: a flat winding electrode assembly formed by winding a positive electrode having a rectangular shape and a negative electrode having a rectangular shape with a separator having a rectangular shape and being interposed therebetween;an outer body storing the flat winding electrode assembly and a nonaqueous electrolyte;a prismatic outer body having an opening portion and a bottom, storing the winding electrode assembly;a sealing plate sealing the opening portion; andat least one rib,the positive electrode collector includes a first region, a second region, a third region, a fourth region, a first bent portion, and second bent portion,the first region is disposed between the sealing plate and the winding electrode assembly,the first region is disposed substantially parallel to the sealing plate,the second region extends from an end of the sealing plate toward the bottom,the fourth region is disposed on an outer surface of the positive electrode substrate exposed portion,the third region connects between the second region and the fourth region,the first bent portion is formed at a boundary between the second region and the third region,the second bent portion is formed at a boundary between the third region and the fourth region,the flat winding electrode assembly including a positive electrode substrate exposed portion wound on one end and a negative electrode substrate exposed portion wound on the other end,the positive electrode substrate exposed portion having a melting area of 2.7 mm2 or more in a plane passing through a central axis of a welded connection portion and being perpendicular to a winding axis of the winding electrode assembly within the welded connection portion with a positive electrode collector,the negative electrode substrate exposed portion having a melting area of 1.8 mm2 or more in a plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with a negative electrode collector,the melting area of the positive electrode substrate exposed portion being greater than the melting area of the negative electrode substrate exposed portion,the winding number of the wound positive electrode substrate exposed portion being 30 or more, and the winding number of the wound negative electrode substrate exposed portion being 30 or more,the wound positive electrode substrate exposed portion having an outermost surface welded and connected with the positive electrode collector, and the wound negative electrode substrate exposed portion having an outermost surface welded and connected with the negative electrode collector,the nonaqueous electrolyte containing a lithium salt having an oxalate complex as an anion at the time of making the nonaqueous electrolyte second battery,all of the layers of the positive electrode substrate exposed portion being melted at the welded connection portion between the positive electrode substrate exposed portion and the positive electrode collector to be welded and connected to the positive electrode collector,all of the layers of the negative electrode substrate exposed portion being melted at the welded connection portion between the negative electrode substrate exposed portion and the negative electrode collector to be welded and connected to the negative electrode collector,the melting area of the positive electrode substrate exposed portion in the plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with the positive electrode collector is smaller than a projected area of the rib onto a plane perpendicular to the winding axis of the winding electrode assembly by projecting in the direction of the winding axis of the winding electrode assembly, andthe rib is provided on an end on the center side of the flat winding electrode assembly of the fourth region and is substantially perpendicular to the fourth region, the length of the rib in a direction perpendicular to the sealing plate is smaller than the length of fourth region in the direction perpendicular to the sealing plate. 14. The nonaqueous electrolyte secondary battery according to claim 13, whereinthe melting area of the positive electrode substrate exposed portion in the plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with the positive electrode collector has a length in a direction perpendicular to the sealing plate shorter than that of the rib in the direction perpendicular to the sealing plate. 15. The nonaqueous electrolyte secondary battery according to claim 14, wherein the positive electrode collector is formed by using aluminum or an aluminum alloy, the positive electrode substrate exposed portion is formed by using aluminum or an aluminum alloy,the negative electrode collector is formed by using copper or a copper alloy,the negative electrode substrate exposed portion is formed by using copper or a copper alloy, andthe welded connection portion of the positive electrode and the welded connection portion of the negative electrode have mechanical strength substantially equivalent to each other. 16. A nonaqueous electrolyte secondary battery comprising: a flat winding electrode assembly formed by winding a positive electrode having a rectangular shape and a negative electrode having a rectangular shape with a separator having a rectangular shape and being interposed therebetween;an outer body storing the flat winding electrode assembly and a nonaqueous electrolyte;a prismatic outer body having an opening portion and a bottom, storing the winding electrode assembly; anda sealing plate sealing the opening portion, whereinthe flat winding electrode assembly including a positive electrode substrate exposed portion wound on one end and a negative electrode substrate exposed portion wound on the other end,the positive electrode substrate exposed portion having a melting area of 2.7 mm2 or more in a plane passing through a central axis of a welded connection portion and being perpendicular to a winding axis of the winding electrode assembly within the welded connection portion with a positive electrode collector,the negative electrode substrate exposed portion having a melting area of 1.8 mm2 or more in a plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with a negative electrode collector,the melting area of the positive electrode substrate exposed portion being greater than the melting area of the negative electrode substrate exposed portion,the winding number of the wound positive electrode substrate exposed portion being 30 or more, and the winding number of the wound negative electrode substrate exposed portion being 30 or more,the wound positive electrode substrate exposed portion having an outermost surface welded and connected with the positive electrode collector, and the wound negative electrode substrate exposed portion having an outermost surface welded and connected with the negative electrode collector,the nonaqueous electrolyte containing a lithium salt having an oxalate complex as an anion at the time of making the nonaqueous electrolyte second battery,all of the layers of the positive electrode substrate exposed portion being melted at the welded connection portion between the positive electrode substrate exposed portion and the positive electrode collector to be welded and connected to the positive electrode collector,all of the layers of the negative electrode substrate exposed portion being melted at the welded connection portion between the negative electrode substrate exposed portion and the negative electrode collector to be welded and connected to the negative electrode collector,the positive electrode collector includes a first region, a second region, a third region, a fourth region, a first bent portion, and second bent portion,the first region is disposed between the sealing plate and the winding electrode assembly,the first region is disposed substantially parallel to the sealing plate,the second region extends from an end of the sealing plate toward the bottom,the fourth region is disposed on an outer surface of the positive electrode substrate exposed portion,the third region connects between the second region and the fourth region,the first bent portion is formed at a boundary between the second region and the third region,the second bent portion is formed at a boundary between the third region and the fourth region,the melting area of the positive electrode substrate exposed portion in the plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with the positive electrode collector has a length in a direction perpendicular to the sealing plate shorter than that of the second region in the direction perpendicular to the sealing plate, andthe fourth region is directly connected to the positive electrode substrate exposed portion by welding. 17. The nonaqueous electrolyte secondary battery according to claim 16, wherein the melting area of the positive electrode substrate exposed portion in the plane passing through the central axis of the welded connection portion and being perpendicular to the winding axis of the winding electrode assembly within the welded connection portion with the positive electrode collector has a length in a direction perpendicular to the sealing plate shorter than that of the third region in the direction perpendicular to the sealing plate. 18. The nonaqueous electrolyte secondary battery according to claim 17, wherein the positive electrode collector is formed by using aluminum or an aluminum alloy,the positive electrode substrate exposed portion is formed by using aluminum or an aluminum alloy,the negative electrode collector is formed by using copper or a copper alloy,the negative electrode substrate exposed portion is formed by using copper or a copper alloy, andthe welded connection portion of the positive electrode and the welded connection portion of the negative electrode have mechanical strength substantially equivalent to each other. 19. The nonaqueous electrolyte secondary battery according to claim 11, wherein the at least one rib comprises a plurality of ribs,the plurality of ribs are separated each other in the direction perpendicular to the sealing plate. 20. The nonaqueous electrolyte secondary battery according to claim 16, further comprising: a plurality of ribs provided on an end the center side of the flat winding electrode assembly of the fourth region, the rib is substantially perpendicular to the fourth region,wherein the length of each of the plurality of ribs in a direction perpendicular to the sealing plate is smaller than the length of fourth region in the direction perpendicular to the sealing plate,the plurality of ribs are separated each other in the direction perpendicular to the sealing plate.
