US-12620597-B2 - Secondary battery, battery pack, electronic device, electric tool, electric aircraft, and electric vehicle

Abstract

Provided is a secondary battery, where a positive electrode includes a first covered part covered with a positive electrode active material layer and a positive electrode active material non-covered part on a positive electrode foil, and a negative electrode includes a second covered part covered with a negative electrode active material layer and a negative electrode active material non-covered part on a negative electrode foil, the positive electrode active material non-covered part is joined to the positive electrode current-collecting plate at one end of an electrode wound body, and the negative electrode active material non-covered part is joined to the negative electrode current-collecting plate at the other end of the electrode wound body.

Inventors

• Akira Otani

Assignees

• MURATA MANUFACTURING CO., LTD.

Dates

Publication Date

20260505

Application Date

20220121

Priority Date

20190730

Claims (18)

1. 1 . A secondary battery comprising: an electrode wound body that has a positive electrode and a negative electrode stacked with a separator interposed therebetween and has a wound structure; and a positive electrode current-collecting plate and a negative electrode current-collecting plate, wherein the electrode wound body, the positive electrode current-collecting plate and the negative electrode current-collecting plate are accommodated in an exterior can, wherein the positive electrode includes a first covered part covered with a positive electrode active material layer and a positive electrode active material non-covered part on a positive electrode foil, the negative electrode includes a second covered part covered with a negative electrode active material layer and a negative electrode active material non-covered part on a negative electrode foil, the positive electrode active material non-covered part is joined to the positive electrode current-collecting plate at one end of the electrode wound body, the negative electrode active material non-covered part is joined to the negative electrode current-collecting plate at the other end of the electrode wound body, one or both of the positive electrode active material non-covered part and the negative electrode active material non-covered part have a surface formed by bending toward a central axis of the wound structure and overlapping each other, and at least parts of the active material non-covered parts near the central axis are multiply bent to include a plurality of multiply bent parts in a case of observing sections of the active material non-covered parts in a plane including the central axis, wherein the multiply bent parts directly overlap each other in a repeating zigzag structure, which is disposed between at least one of: the first covered part and the positive electrode current-collecting plate, or the second covered part and the negative electrode current-collecting plate.
2. 2 . The secondary battery according to claim 1 , wherein a number of the active material non-covered parts multiply bent near the central axis is 5 or more and 15 or less counted from the central axis.
3. 3 . The secondary battery according to claim 2 , wherein the active material non-covered parts multiply bent is in a region that has a depth of 0.1 mm or more and 1.5 mm or less from the surface.
4. 4 . The secondary battery according to claim 1 , wherein the active material non-covered parts multiply bent is in a region that has a depth of 0.1 mm or more and 1.5 mm or less from the surface.
5. 5 . The secondary battery according to claim 1 , wherein the surface has a groove.
6. 6 . The secondary battery according to claim 1 , wherein the surface includes a flat surface or a surface with a raised part.
7. 7 . The secondary battery according to claim 1 , wherein a width of the positive electrode active material non-covered part is larger than a width of the negative electrode active material non-covered part, an end of the positive electrode active material non-covered part and an end of the negative electrode active material non-covered part is protruded outward from the separator, and a length of a part of the positive electrode active material non-covered part protruded from one end of the separator in a width direction is larger than a length of a part of the negative electrode active material non-covered part protruded from the other end of the separator in the width direction.
8. 8 . The secondary battery according to claim 1 , wherein a part of the positive electrode active material non-covered part that faces the negative electrode with the separator interposed therebetween has an insulating layer.
9. 9 . The secondary battery according to claim 1 , wherein a material of the positive electrode foil includes aluminum or an aluminum alloy.
10. 10 . The secondary battery according to claim 1 , wherein a material of the negative electrode foil includes a simple substance of nickel, a nickel alloy, copper, a copper alloy, or a composite thereof.
11. 11 . A battery pack comprising: the secondary battery according to claim 1 ; a controller configured to control the secondary battery; and an exterior body that encloses the secondary battery.
12. 12 . An electronic device comprising the battery pack according to claim 11 .
13. 13 . An electric tool comprising the battery pack according to claim 11 , wherein the electric tool is configured to use the battery pack as a power supply.
14. 14 . An electric aircraft comprising: the battery pack according to claim 11 ; a plurality of rotor blades; a motor that rotates each of the rotor blades; a support shaft that supports each of the rotor blades and the motor; a motor controller configured to control rotation of the motor; and a power supply line that supplies power to the motor, wherein the battery pack is connected to the power supply line.
15. 15 . The electric aircraft according to claim 14 , comprising: a plurality of pairs of the rotor blades facing each other; and a plurality of the battery packs, wherein the plurality of pairs of rotor blades and the plurality of battery packs are equal in number.
16. 16 . An electronic device comprising the secondary battery according to claim 1 .
17. 17 . An electric vehicle including the secondary battery according to claim 1 , comprising: a conversion device that receives power supply from the secondary battery to convert the power to a driving force for the electric vehicle; and a controller configured to perform information processing related to vehicle control, based on information on the second battery.
18. 18 . The secondary battery according to claim 1 , wherein at the end surface in a cross-section including the central axis, the multiply-bent parts are denser near the central axis than near an outer peripheral side.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation of PCT patent application no. PCT/JP2020/028295, filed on Jul. 21, 2020, which claims priority to Japanese patent application no. JP2019-139813 filed on Jul. 30, 2019, the entire contents of which are being incorporated herein by reference. BACKGROUND The present disclosure generally relates to a secondary battery, a battery pack, an electronic device, an electric tool, an electric aircraft, and an electric vehicle. Lithium ion batteries have been developed for applications that require high power, such as electric tools and automobiles. Methods for achieving high power include a method of high-rate discharge for the flow of a relatively large current from a battery. The high-rate discharge has a problem with the internal resistance of the battery, because of the flow of the large current. SUMMARY The present disclosure generally relates to a secondary battery, a battery pack, an electronic device, an electric tool, an electric aircraft, and an electric vehicle. The conventional battery technology, for example, has a problem in that, because welding points are denser toward the center in order to collect current from the whole wound foil ends, simply folding and overlapping the foil produces a region with less overlap of the foils on the center side of the electrode assembly, which is perforated at the time of welding. Moreover, another problem is that a sufficient space is required in the central part of the electrode assembly at the time of can bottom welding in the assembly process, and when the foil is folded from the outer periphery toward the central part, the central space formed at the time of the winding is blocked, thereby failing to achieve the assembly. Accordingly, an object of the present disclosure is to provide a battery for high-rate discharge, which can be reliably welded. For solving the above-described problems, the present disclosure provides a secondary battery according to an embodiment including: an electrode wound body that has a positive electrode and a negative electrode stacked with a separator interposed therebetween and has a wound structure; and a positive electrode current-collecting plate and a negative electrode current-collecting plate, accommodated in an exterior can, where the positive electrode includes a first covered part covered with a positive electrode active material layer and a positive electrode active material non-covered part on a positive electrode foil,the negative electrode includes a second covered part covered with a negative electrode active material layer and a negative electrode active material non-covered part on a negative electrode foil,the positive electrode active material non-covered part is joined to the positive electrode current-collecting plate at one end of the electrode wound body,the negative electrode active material non-covered part is joined to the negative electrode current-collecting plate at the other end of the electrode wound body,one or both of the positive electrode active material non-covered part and the negative electrode active material non-covered part have a surface formed by bending toward the central axis of the wound structure and overlapping each other, andat least parts of the active material non-covered parts near the central axis are multiply bent in the case of observing sections of the active material non-covered parts in the plane including the central axis. Further, the present disclosure provides a battery pack including: the secondary battery as described herein;a controller configured to control the secondary battery; andan exterior body that encloses the secondary battery. The present disclosure provides an electronic device including the secondary battery as described herein or the battery pack as described herein. The present disclosure provides an electric tool according to an embodiment including the battery pack described above, which is configured to use the battery pack as a power supply. The present disclosure provides an electric aircraft according to an embodiment including: the battery pack as described herein;a plurality of rotor blades;a motor that rotates each of the rotor blades;a support shaft that supports each of the rotor blades and the motor;a motor controller configured to control rotation of the motor; anda power supply line that supplies power to the motor,where the battery pack is connected to the power supply line. The present disclosure provides an electric vehicle according to an embodiment including the secondary battery described above, including a conversion device that receives power supply from the secondary battery to convert the power to a driving force for the electric vehicle, anda controller configured to perform information processing related to vehicle control, based on information on the second battery. According to at least an embodiment of the present disclosure, the foil and the current