Battery, battery pack, electronic device, electrically driven vehicle, electric storage device, and electric power system
The battery is provided. The battery includes an electrode. The electrode includes a current collector and an active material layer provided on an inside surface of the current collector. The active material layer includes a first region and a second region, where the second region includes an area density lower than the first region, and the second region is provided in a winding-back portion of the active material layer.
1. A battery comprising an electrode,
wherein
the electrode includes a current collector and an active material layer provided on an inside surface of the current collector,
the active material layer includes a first region and a second region, wherein the second region includes an area density lower than the first region, and
the second region is provided in a winding-back portion of the active material layer; and
wherein the second region includes a recess having a bottom surface.
2. The battery according to claim 1 , wherein a thickness of the active material layer in the second region is thinner than a thickness of the active material layer in the first region.
3. The battery according to claim 1 , wherein the winding-back portion includes a first winding-back portion of an innermost periphery of the active material layer.
4. The battery according to claim 1 , wherein the winding-back portion includes a first winding-back portion on a first side of an innermost periphery of the active material layer, and a second winding-back portion on a second side of the innermost periphery of the active material layer.
5. The battery according to claim 1 , wherein the winding-back portion includes winding-back portions of first and second turns of the active material layer.
6. The battery according to claim 1 , wherein an area density ratio D 2 /D 1 of an average area density D 2 of the active material layer in the second region to an average area density D 1 of the active material layer in the first region satisfies a relationship of 0<D 2 /D 1 ≤0.9.
7. The battery according to claim 1 , wherein a width of the second region in a longitudinal direction of the electrode ranges from 1 mm to 20 mm.
8. The battery according to claim 1 , wherein a width of the second region in a longitudinal direction of the electrode ranges from 5 mm to 20 mm.
9. The battery according to claim 1 , wherein the electrode includes a positive electrode.
10. The battery according to claim 9 , wherein
the current collector includes aluminum or aluminum alloy, and
a thickness of the current collector ranges from 8 μm to 15 μm.
11. The battery according to claim 9 , wherein an average area density of the active material layer in the first region is greater than or equal to 12.5 mg/cm 2 .
12. The battery according to claim 1 , wherein
the second region includes a recess, and
the recess is open while the electrode is wound.
13. A battery pack comprising:
the battery according to claim 1 ; and
a controller configured to control the battery.
14. An electronic device comprising the battery according to claim 1 , wherein power is configured to be supplied from the battery to the electronic device.
15. An electric vehicle comprising:
the battery according to claim 1 ;
a converter is configured to receive power from the battery to convert the power into driving force of the electric vehicle; and
a control device is configured to perform information processing relating to vehicle control based on information about the battery.
16. An electric storage device comprising the battery according to claim 1 , wherein the electric storage device is configured to supply power to an electronic device connected to the battery.
17. An electric power system comprising the battery according to claim 1 , wherein the electric power system is configured to receive supply of power from the battery.
18. The battery according to claim 1 , wherein the electrode includes a flat shape electrode configured to be wound from a belt-shaped electrode.