Battery and battery manufacturing method
A battery having a bundle of electrodes and separator which is made by winding a positive-electrode plate and a negative-electrode plate together with a separator therebetween, one of the positive- and negative-electrode plates being electrically connected to a power collecting body, the power collecting body being provided in and welded to an outer package can, wherein a welding portion of the outer package can and the power collecting body comprises a first layer and a second layer which are stacked in a thickness direction of the outer package can at the welding portion, and the second layer is in contact with a surface of the first layer and includes crystal grains that are minuter than crystal grains included in the first layer.
1. A battery having a bundle of electrodes and separator which is made by winding a positive-electrode plate and a negative-electrode plate together with a separator therebetween, one of the positive- and negative-electrode plates being electrically connected to a power collecting body, the power collecting body being provided in and welded to an outer package can, wherein
a welding portion of the outer package can and the power collecting body comprises a first layer and a second layer which are stacked in a thickness direction of the outer package can at the welding portion, and
the second layer is in contact with a surface of the first layer and is comprised of crystal grains that are minuter than crystal grains of the first layer;
wherein the first layer and the second layer are formed by beam welding.
2. The battery of claim 1 , wherein the welding portion further includes another first layer on an opposite side of the second layer, the second layer being sandwiched between the two first layers.
3. The battery of claim 1 , wherein
the outer package can is in a shape of a cylinder with a bottom, and
the power collecting body is welded to the bottom of the outer package can by energy beams applied from outside the outer package can.