Secondary battery electrode and method for producing the electrode
The electrodes disclosed herein, a low-density region having a relatively low electrode density and a high-density region having a relatively high electrode density are repeated on a surface of the electrode active material layer in a predetermined pattern at a constant pitch. The electrode active material layer is evenly divided into three layers of an upper layer, an intermediate layer, and a lower layer in a thickness direction from the surface of the active material layer to the electrode current collector, and when the electrode densities (g/cm 3 ) of the upper layer, the intermediate layer, and the lower layer of the low-density region are respectively d L1 , d L2 , and d L3 and the electrode densities (g/cm 3 ) of the upper layer, the intermediate layer, and the lower layer of the high-density region are respectively d H1 , d H2 , and d H3 , a relation of d H3 /d L3 <d H1 /d L1 is satisfied.
1. A secondary battery electrode that is either a positive or negative electrode of a secondary battery, the secondary battery electrode comprising:
an electrode current collector; and
an electrode active material layer formed on the electrode current collector, wherein
a low-density region having a relatively low electrode density and a high-density region having a relatively high electrode density are repeated on a surface of the electrode active material layer in a predetermined pattern at a constant pitch, and
with the electrode active material layer being evenly divided into three layers of an upper layer, an intermediate layer, and a lower layer in a thickness direction from the surface of the electrode active material layer to the electrode current collector, and
the electrode densities (g/cm 3 ) of the upper layer, the intermediate layer, and the lower layer of the low-density region are respectively d L1 , d L2 , and d L3 , and
the electrode densities (g/cm 3 ) of the upper layer, the intermediate layer, and the lower layer of the high-density region are respectively d H1 , d H2 , and d H3 ,
a relation of (d H3 /d L3 )<(d H1 /d L1 ) is satisfied.
2. The secondary battery electrode according to claim 1 , wherein
the upper layer d L1 and the lower layer d L3 of the low-density region in the electrode active material layer have a relation of (d L1 /d L3 )<1.1.
3. The secondary battery electrode according to claim 1 , wherein
the low-density region and the high-density region are repeated at a pitch of 250 μm or more and 5 mm or less.
4. The secondary battery electrode according to claim 1 , wherein
the surface of the electrode active material layer has a concave/convex shape with a predetermined pattern,
the low-density region is formed in a concave portion of the concave/convex shape, and
the high-density region is formed in a convex portion of the concave/convex shape.