WO-2026094755-A1 - CYLINDRICAL BATTERY

WO2026094755A1WO 2026094755 A1WO2026094755 A1WO 2026094755A1WO-2026094755-A1

Abstract

In this cylindrical battery, a negative electrode mixture layer (12b) of a negative electrode (12) extends from a winding inner side of a positive electrode starting end (40), which is a leading end on a winding start side of a positive electrode (11), to the winding start side. In the positive electrode (11), a tape (50) is adhered to a portion including a center (L1) in the winding axis direction of at least one surface of a winding inner surface or a winding outer surface of the positive electrode starting end part. In the positive electrode (11), no tape is adhered to both end parts in the winding axis direction of at least one surface of the positive electrode starting end part.

Inventors

KATO GENICHIRO

Assignees

パナソニックＩＰマネジメント株式会社

Dates

Publication Date: 20260507
Application Date: 20251023
Priority Date: 20241031

Claims (4)

An electrode body is formed by winding a strip-shaped positive electrode having a positive electrode core and a positive electrode mixture layer, and a strip-shaped negative electrode having a negative electrode core and a negative electrode mixture layer, with a separator in between. A bottomed cylindrical outer container housing the electrode body, The outer can is equipped with a sealing body that closes the opening of the outer can, The negative electrode mixture layer extends from the inside of the winding side of the positive electrode starting end, which is the tip of the positive electrode winding starting side, towards the winding starting side. The positive electrode has tape attached to a portion of at least one of the winding inner surface and winding outer surface of the positive electrode starting end, including the center in the winding axis direction, In the positive electrode, the tape is not attached to both ends in the winding axis direction of at least one face of the starting end of the positive electrode. Cylindrical battery.
The length of the tape in the winding axis direction is 1/3 or more and 2/3 or less of the length of the positive electrode in the winding axis direction. The cylindrical battery according to claim 1.
In the tape, the length of the portion covering at least one surface in the winding direction is 1 mm or more and 5 mm or less. The cylindrical battery according to claim 1.
The tape is attached to both sides in the thickness direction of the positive electrode starting end and covers the end face of the positive electrode starting end. The cylindrical battery according to claim 1.

Description

Cylindrical battery This disclosure relates to cylindrical batteries. Conventionally, cylindrical batteries include those described in Patent Document 1. This cylindrical battery comprises an electrode body in which a positive electrode and a negative electrode are wound with a separator in between. In this cylindrical battery, a negative electrode lead is attached to the portion of the negative electrode wound at least one turn from the inner end in the winding direction, without facing the positive electrode via the separator. An insulating tape is attached to the negative electrode core body so as to span the surface of the negative electrode lead. This is said to suppress electrode plate deformation associated with charge-discharge cycles in the electrode body. The inventors of this invention have found that when a cylindrical battery is charged and discharged, the gap between the negative electrode near the starting end of the positive electrode in the electrode body becomes smaller, and the separator interposed in this gap is pressed from near the center of the winding axis at the starting end of the positive electrode, which may cause a voltage drop. On the other hand, cylindrical batteries require suppression of the decrease in battery capacity. Therefore, the object of this disclosure is to provide a cylindrical battery that can suppress the decrease in battery capacity and suppress the voltage drop associated with charging and discharging. The cylindrical battery according to this disclosure comprises an electrode body in which a strip-shaped positive electrode having a positive electrode core and a positive electrode mixture layer, and a strip-shaped negative electrode having a negative electrode core and a negative electrode mixture layer are wound via a separator; a bottomed cylindrical outer casing housing the electrode body; and a sealing body that closes the opening of the outer casing. The negative electrode mixture layer extends from the inside of the winding to the winding start side of the positive electrode start end, which is the tip of the winding start side of the positive electrode. Tape is attached to the portion of at least one surface of the winding inner surface and the winding outer surface of the positive electrode start end, including the center in the winding axis direction. Tape is not attached to both ends in the winding axis direction of at least one surface of the positive electrode start end. According to the cylindrical battery of this disclosure, the pressure on the separator near the center of the winding axis direction at the positive electrode starting end can be suppressed, thereby suppressing voltage drop associated with charging and discharging. Furthermore, since tape is not attached to the positive electrode mixture layer at both ends of the winding axis direction on at least one side of the positive electrode starting end, a decrease in battery capacity can be suppressed. This is a cross-sectional view along the axial direction of a cylindrical battery according to an embodiment of the present disclosure.In this embodiment, the cross-sectional view is perpendicular to the winding axis direction of the electrode body and shows the vicinity of the positive electrode starting end.This diagram shows the inner surface of the positive electrode starting end (the end where the winding begins) and the outer surface of the negative electrode starting end (the end where the winding begins) unfolded in the longitudinal direction.This is a cross-sectional view taken along line A-A in Figure 3.This is an enlarged view of section B in Figure 3, which is a cylindrical battery in another embodiment.This is a cross-sectional view taken along line C-C in Figure 5.This figure corresponds to Figure 5, showing a cylindrical battery in another embodiment.This is a cross-sectional view taken along line D-D in Figure 7.This figure corresponds to Figure 8, showing a cylindrical battery in another embodiment. The embodiments of the cylindrical battery according to this disclosure will be described in detail below with reference to the drawings. The cylindrical battery of this disclosure may be a primary battery or a secondary battery. Furthermore, it may use either an aqueous electrolyte or a non-aqueous electrolyte. In the following description, a non-aqueous electrolyte secondary battery (lithium-ion battery) using a non-aqueous electrolyte will be given as an example of one embodiment of the cylindrical battery 10, but the cylindrical battery of this disclosure is not limited to this, and the electrolyte may also be an aqueous electrolyte. It is anticipated from the outset that new embodiments can be constructed by appropriately combining the characteristic features of the embodiments and modifications described below. In the following embodiments, the same reference numerals are used for the same components in the drawings, and redundant explanations are omitted. Furthermore, mult