JPH09147915A - Cylindrical nonaqueous electrolyte secondary cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the safety of a cell by restraining temperature within the cell from being increased because of fine short-circuit developed within the cell when the cylindrical nonaqueous electrolyte secondary cell in a fully charged condition is deformed. SOLUTION: In the cylindrical nonaqueous electrolyte secondary cell, electrode groups are housed in a cylindrical case 5, in which each positive and each negative plate 1 and 3 provided with each pole plate in continuous length stuck with current collecting lead parts 2 and 4 in a shape of a strip of paper, are wound in a whirlpool shape via separator. A part or the whole of each current collecting lead part 2 and 4 is made to form an angle made by two lines connecting a winding core with both the ends of the current collecting lead part in the width direction of the other pole plate, and is located in a range of a circular arc portion the radius of which is the radius of the cylindrical case 5, and the distance between both the lead parts 2 and 4 shall be less than the lateral width of the corrent collecting lead part short in lateral width.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical non-aqueous electrolyte secondary battery, and more particularly to the positional relationship of the lead portions of its positive and negative electrode plates.

[0002]

2. Description of the Related Art A cylindrical non-aqueous electrolyte secondary battery using an organic electrolyte and an alkali metal such as lithium as a negative electrode active material has a higher energy density than an aqueous secondary battery. Are gathering. However, when metallic lithium is used as the negative electrode, active lithium generated by charging reacts with the organic solvent of the electrolytic solution, and the deposited lithium grows in the form of dendrite, and the insulating layer is formed by the reaction between the deposited lithium and the solvent. Lithium, which has no electronic conductivity, is generated (R. Selim and Bro, J. El.
ectrochem.Soc, 121, 1457 (1974)), there was a problem that the charge and discharge efficiency of the lithium electrode was poor.

Further, there is a problem that an internal short circuit of a battery occurs due to lithium grown in a dendrite shape,
A practically sufficient secondary battery has not been obtained.

As a battery which avoids such problems and has a high energy density, a non-aqueous electrolyte secondary battery using a carbon material as a negative electrode has been proposed, which is combined with a positive electrode using a lithium-containing oxide. I am using.

[0005]

However, in a cylindrical battery using a carbon material as a negative electrode, the battery is deformed due to pressure applied to the side surface of the battery in a charged state in which lithium is occluded in the carbon material. It is said that the temperature inside the battery rises when the condition is reached.

Although the detailed mechanism of the temperature rise in the crushed state is unknown, in the battery in the charged state, the positive and negative electrode plates and the separator of the crushed portion are broken, so that the metal current collector of the positive electrode plate is collected inside the battery. The body lead portion and the metal current collector lead portion of the negative electrode plate overlap with each other to cause a minute short circuit. There is a possibility that a spark may occur at the part where a minute short circuit occurs in the order of several microns, and there is a possibility that a spark will occur.Since it is a minute short circuit, there is sufficient energy in the electrode group. ing. It is speculated that the temperature rise will occur if a minute spark occurs in the battery in the presence of sufficient energy.

The present invention is intended to solve this problem and prevents the occurrence of a minute short circuit in the battery when the cylindrical non-aqueous electrolyte secondary battery in a charged state is deformed due to pressure. This prevents the temperature of the battery from rising.

[0008]

In order to solve the above-mentioned problems, a cylindrical non-aqueous electrolyte secondary battery of the present invention comprises a long electrode plate and a strip-shaped current collecting lead portion. , A negative electrode plate is wound in a spiral shape through a separator, and the electrode plate group is housed in a cylindrical case. Has an angle connecting both ends in the lateral width direction of the current collecting lead portion of the electrode plate, and is located within the range of the arc portion whose radius is the radius of the cylindrical case,
The distance between both lead portions is less than or equal to the width of the current collecting lead portion having a short width.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an angle connecting a part or all of the current collecting lead portion of one electrode plate to both ends of the current collecting lead portion of the other electrode plate in the lateral width direction. Since it is located within the range of the circular arc part whose radius is the radius of the cylindrical case and the distance between both lead parts is less than or equal to the lateral width of the short current collecting lead part, Even when a pressure is applied from the direction to the crushed state, the lead portion of the positive electrode and the lead portion of the negative electrode easily contact each other, and a strong short circuit can be caused. That is, a structure that does not cause a minute short circuit between the positive electrode plate and the negative electrode plate inside the battery, in other words, a structure that causes a strong short circuit before a spark occurs, reduces the energy of the electrode plate group and reduces the spark It is possible to suppress the generation and prevent the temperature rise in the battery.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

In the non-aqueous electrolyte secondary battery of the present invention, LiCO ₂ was used for the positive electrode and graphite capable of inserting and extracting lithium was used for the negative electrode.

The positive electrode plate 1 is long and has a length of 50 mm and a width of 400.
mm, the thickness is 0.2 mm, and the current collector metal lead portion 2 of the positive electrode plate has a strip shape of 70 mm in length, 5 mm in width, and 0.15 in thickness
mm.

On the other hand, the negative electrode plate 3 is elongated and has a length of 55 mm, a width of 500 mm and a thickness of 0.2 mm, and the current collecting metal lead portion 4 of the negative electrode plate is a strip shape of a length of 70 mm, a width of 4 mm and a thickness of 0.15 mm. And

A cylindrical battery case 5 is formed by spirally winding these positive and negative plates through a separator to form an electrode plate group.
It was housed inside and a battery of the present invention was produced. A view of this battery as seen from above the battery case is shown in FIGS. As shown in FIG. 1, all or a part of the current collecting lead portion 4 of the negative electrode plate has an angle connecting the winding core 5 and both ends a and b in the lateral direction of the current collecting lead portion 2 of the positive electrode plate. It is located within the range of the arc portion 6 whose radius is the radius of the cylindrical battery case 5. The distance between the positive electrode plate and the negative electrode plate is 2 mm.
The batteries shown in FIGS. 1A and 1B were referred to as batteries A and B of the present invention, respectively.

Further, the positional relationship between the current collecting lead portion of the positive electrode plate and the current collecting lead portion of the negative electrode plate is shown in FIGS.
The batteries as shown in (C) are comparative batteries C, D, and E.
And

Two batteries were used for comparison with the present invention.
Use 0 each, current 840mA, 4.2V cut 2
The constant voltage charging of time was performed. The results of the number of batteries that ignited when the batteries in this charged state were crashed with a round bar are shown in (Table 1).

[0017]

[Table 1]

As shown in (Table 1), comparative batteries C to
In E, most of the batteries generated sparks due to a minute short circuit inside the batteries, and the battery temperature increased.

On the other hand, in the batteries A and B of the present invention,
A strong internal short circuit occurred due to the strong contact between the positive and negative electrode current collecting leads, and it was possible to suppress the occurrence of sparks and prevent the temperature rise in the battery.

[0020]

As described above, in the present invention, part or all of the current collecting lead portion of one electrode plate is provided with the winding core and both ends of the current collecting lead portion of the other electrode plate in the lateral width direction. It has a connecting angle and is located within the range of the arc part whose radius is the radius of the cylindrical case, and the distance between both lead parts is less than or equal to the lateral width of the short current collecting lead part. The lead portion of the positive electrode and the lead portion of the negative electrode are easily contacted with each other regardless of the direction in which the pressure is applied to cause deformation. Therefore, a strong short circuit can occur before a spark occurs in the battery, and the temperature inside the battery can be prevented from rising to improve the safety of the battery.

[Brief description of the drawings]

FIG. 1A is a schematic view of a cylindrical non-aqueous electrolyte secondary battery of the present invention seen from above. FIG. 1B is a schematic view showing another example of the battery.

FIG. 2A is a schematic view of a battery used for comparison seen from above. FIG. 2B is a schematic view showing another example of the battery. FIG. 2C is a schematic view showing another example of the battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Current collecting lead part of positive electrode plate 3 Negative electrode plate 4 Current collecting lead part of negative electrode plate 5 Cylindrical battery case 6 Arc part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Rinkichi Yonehara 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A group of electrode plates obtained by spirally winding a positive electrode plate and a negative electrode plate each having a strip-shaped current collecting lead portion on a long electrode plate with a separator interposed between the electrode plates. A part or all of the current collecting lead portion of one electrode plate has an angle connecting the winding core and both ends of the current collecting lead portion of the other electrode plate in the lateral width direction, and has a cylindrical radius. A cylindrical non-aqueous electrolyte secondary battery, which is located within a range of an arc portion which is a radius of a case, and a distance between both lead parts is equal to or less than a lateral width of a current collecting lead part having a short lateral width. 2. The cylindrical non-aqueous electrolyte secondary battery according to claim 1, wherein the distance between both lead portions is 4 mm or less.