JPH05290826A - Organic electrolyte battery - Google Patents

Abstract

PURPOSE:To provide an organic electrolyte battery having high safety with an internal short circuit due to a negative electrode collecting tab prevented. CONSTITUTION:A positive electrode plate 3 is arranged in the outermost periphery of an electrode winding article 5 in an organic electrolyte battery. A negative electrode collecting tab 2, connected to a negative electrode plate 1, is extended in a winding direction from the winding-finished end part of the negative electrode plate 1, is drawn out in the outer surface of the electrode winding article 5, is extended in the axial direction of the electrode winding article 5 wound in a spiral state in the outer surface of the electrode winding article 5, and is crossing the end part of the positive electrode plate 3 to be linked to a sheathing can 9. Consequently the deposit of active material, remaining in the negative collecting tab, in the positive electrode plate at the time of over discharge is eliminated. Also it is eliminated that the negative electrode collecting tab is folded to contact the positive electrode plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery structure of an organic electrolyte battery, and more particularly to an organic electrolyte battery having an improved structure for taking out a negative electrode current collecting tab to improve safety.

[0002]

2. Description of the Related Art A conventional organic electrolyte battery having an outer can as a negative electrode has the following structure as a structure for taking out a negative electrode current collecting tab 2.
There is a structure of. As shown in FIG. 1, the negative electrode plate 1 is arranged on the outermost periphery of the electrode roll 5 and the negative electrode collector tab 2 is attached to the outermost periphery of the negative electrode plate 1. FIGS. 2 and 3 show a state in which the positive electrode plate 3 and the negative electrode plate 1 used for the electrode winding product 5 of this structure are spread out in a plane. The positive electrode plate 3 is connected to the positive electrode current collecting tab 4 at its central portion, and the negative electrode plate 1 is connected to the negative electrode current collecting tab 2 at its terminal portion. As shown in FIG. 4, the positive electrode plate 3 is arranged on the outermost periphery of the electrode winding product 5. In the electrode winding product 5 having this structure, the negative electrode plate 1 is located inside the positive electrode plate 3. The negative electrode current collector tab 2 is connected to the negative electrode plate 1 inside the positive electrode plate 3 and taken out from the lower end of the electrode winding product 5.

In this specification, the vertical direction of the electrode winding product is determined based on the drawings. The upper side of the electrode winding product is the direction in which the positive electrode current collecting tab projects, and the lower side is the axis of the negative electrode current collecting tab. It shall mean the direction in which the direction extension projects.

[0004]

[Problems to be Solved by the Invention]
In the battery having the structure for taking out the negative electrode current collecting tab as shown in (1), the negative electrode plate 1 remains on the outermost periphery of the electrode winding product 5 in a completely discharged state. This is because the outermost peripheral portion of the negative electrode plate 1 faces the positive electrode plate 3 only on one side. That is, FIG. 5 is a cross-sectional view of the electrode winding product 5 in an undischarged state. Since the positive electrode plate 3 does not exist on the outer surface side of the outermost peripheral portion of the negative electrode plate 1, the discharge reaction occurs only from one surface thereof. On the other hand, since the both surfaces of the portion of the negative electrode plate 1 located inside the electrode winding product 5 face the positive electrode plate 3, the discharge reaction occurs from both surfaces. For this reason, when a negative electrode whose volume is reduced by discharge like lithium is used, the volume reduction rate of the negative electrode plate 1 is smaller in the portion located inside the electrode winding product 5 than in the outermost peripheral portion. And get faster. In the completely discharged state, as shown in the cross-sectional view of the electrode winding product 5 shown in FIG. 6, the outermost peripheral portion of the negative electrode plate 1 remains even when the portion located inside is completely discharged. Will be done. Further, in the state shown in FIG. 6, since the negative electrode current collector tab 2 is still connected to the negative electrode plate 1 remaining on the outermost periphery of the electrode winding product 5, overdischarging may be further performed. At the time of this over-discharge, as shown in FIG. 1, lithium deposition 6 which is a negative electrode active material occurs on the surface of the positive electrode plate 3 facing the negative electrode plate 1 located at the outermost periphery, and the deposited lithium grows to grow the negative electrode. When it reaches, there is a risk of causing an internal short circuit and igniting the battery.

Further, in the structure for taking out the negative electrode current collecting tab, as shown in an enlarged view of FIG. 4, a part of the negative electrode current collecting tab 2 is bent, and the glass tape 7 and the separator 8 are pierced to reach the positive electrode plate 3. May cause touch, short circuit, or fire. For this reason, the structure for taking out the negative electrode current collector tabs includes a potential problem of short circuit and ignition. The present invention was developed as a subject to prevent ignition due to a short circuit with the positive electrode plate due to the structure for taking out the negative electrode current collector tab.

The organic electrolyte battery in which the outer can also serves as the positive electrode terminal does not have such a defect. This is because the negative electrode current collecting tab can be taken out toward the sealing body. As shown in FIG. 4, in the battery, an annular inward protruding portion is formed in the vicinity of the opening of the bottomed cylindrical outer can 9 in which the electrode winding product 5 is housed, and the inner protruding portion is insulated and packed. The sealing body 14 is placed via 13 and the opening of the outer can 9 is caulked. With such a structure, when the battery is vibrated, even if the electrode winding product 5 tries to move upward, it comes into contact with the inner protruding portion of the outer can 9 and moves further upward. I can't. For this reason, the current collecting tab led out above the electrode winding product 5 is not likely to be bent significantly to cause an internal short circuit. In a battery in which the negative electrode current collecting tab is taken out toward the sealing body, the negative electrode current collecting tab is If it is insulated from the positive electrode with a protective tape or the like, there will be no shortage or ignition problems. Further, in order to prevent the wound electrode product 5 from shorting with the outer can 9, the width of the positive electrode plate 3 must be made larger than the width of the negative electrode plate 1. There is no obstacle to the structure. However, in the organic electrolyte battery, the outer can cannot always be the positive electrode. The polarity of the outer can must be adapted to the application.

In the organic electrolyte battery having the outer case as a negative electrode, it is necessary to take out the negative electrode current collecting tab in the can bottom direction. In the battery having this structure, when the negative electrode plate 1 is arranged on the outermost periphery of the electrode winding product 5 and the negative electrode current collecting tab 2 is attached on the outermost periphery thereof, as described above, the battery is over-discharged. At this time, the active material of the negative electrode plate 1 located at the outermost periphery is likely to be deposited on the positive electrode plate 3 facing the short circuit, resulting in short circuit and ignition. In order to prevent this adverse effect, if the entire negative electrode is thinned so that the active material of the negative electrode plate is consumed at the end of discharge, the battery discharge capacity will be halved.

This drawback can be solved by disconnecting the negative electrode plate remaining on the outermost periphery from the negative electrode current collecting tab when the battery is completely discharged. An example thereof is shown in FIGS. 7 and 8. FIG. 7 is an end view of the electrode winding product 5 showing an undischarged state, and FIG. 8 shows a completely discharged state. Also,
As shown in FIG. 9, the negative electrode plate 1 is formed by connecting the negative electrode current collecting tabs 2 by shifting the ends of the negative electrode plate 1 toward the center. In the undischarged state, as shown in FIG. 7, since the negative electrode current collector tab 2 is connected to the negative electrode plate 1, discharge is possible. However, in the fully discharged state, only the outermost negative electrode plate 1 remains, and the negative electrode plate 1 positioned inside the electrode winding product is consumed and disappears. Therefore, the negative electrode plate 1 positioned inside the electrode winding product 5 is consumed. The negative electrode current collector tab 2 connected to is separated from the negative electrode plate 1 remaining on the outermost periphery. Thus, when the negative electrode plate 1 is separated from the negative electrode current collector tab 2, the negative electrode plate 1 is not further discharged, and the remaining active material of the negative electrode plate 1 is deposited on the surface of the positive electrode plate 3 and internally shoots. There is no such thing.

However, the organic electrolyte battery having the negative electrode plate of this structure has another problem. That is, since the negative electrode plate of this structure moves the negative electrode current collecting tab 2 to the center side of the electrode winding product 5, as shown in FIG. 10, the distance d between the negative electrode current collecting tab 2 and the outer can 9 is large. Become. When the negative electrode current collector tab 2 separates from the outer can 9, as shown in the figure, when the molded battery is vibrated, the negative electrode current collector tab 2 "bends", and the bent part breaks the separator 8 and breaks. There is a problem that it contacts the positive electrode plate 3 and causes a short circuit.

That is, the conventional organic electrolyte battery has a drawback that when the negative electrode current collecting tab is brought close to the outer can, an internal short circuit occurs due to the active material deposited on the positive electrode plate during forced discharge.
In order to avoid this drawback, if the negative electrode current collector tab is displaced toward the center of the electrode roll, the negative electrode current collector tab will bend and come into contact with the positive electrode plate, resulting in a short circuit. "Countermeasures against over-discharge"
There is no method that can solve both "tab bending" and
It was an urgent task.

The present invention was developed for the purpose of solving the conventional drawbacks, and an important object of the present invention is to prevent internal short-circuiting due to the negative electrode current collecting tab and to provide a highly safe organic electrolyte. To provide batteries.

[0012]

The organic electrolyte battery of the present invention has the following constitution in order to achieve the above object. That is, the battery of the present invention is an improved one having a structure in which an electrode winding product 5 in which a negative electrode plate 1 and a positive electrode plate 3 are laminated via a separator 8 and spirally wound is housed in an outer can. is there.

A positive electrode plate 3 is arranged on the outermost periphery of the electrode winding product 5 so as to cover the negative electrode plate 1. Further, the negative electrode current collector tab 2 connected to the negative electrode plate 1 has a tangential extension 2A and an axial extension 2B. The tangential extension 2A is connected to the negative electrode plate 1, and the axial extension 2B is connected to the outer can 9. The tangential extension 2A connected to the negative electrode plate 1 is extended from the winding end end of the negative electrode plate 1 in the winding direction and is taken out to the outer surface of the electrode winding product 5. The axial extension 2B is
The outer surface of the electrode winding product 5 is extended in the axial direction of the electrode winding product 5 and protrudes from the lower end of the electrode winding product 5, and is further bent at the corner of the lower end of the electrode winding product 5 to be packaged. It is connected to the can 9.

[0014]

In the organic electrolyte battery of the present invention, the outermost periphery of the electrode winding product 5 is the positive electrode plate 3. Therefore, no active material remains on the outer peripheral portion of the negative electrode plate 1 in a state where the battery is completely discharged. Even when the organic electrolyte battery is completely discharged, the active material of the negative electrode does not deposit on the positive electrode plate 3 to cause an internal short circuit even if it is forcibly discharged.

The negative electrode current collecting tab 2 is extended to the outer surface of the electrode winding product 5 at the tangential extension 2A. The axially extending portion 2B of the negative electrode current collecting tab 2 has its lower end bent at the lower end of the electrode winding product 5 and is connected to the outer can. The negative electrode current collector tab 2 in this state is housed in close contact with the surface of the electrode winding product 5 so as not to separate from the outer can. Negative electrode current collecting tab 2 approaching the outer can
Does not bend due to vibration, and does not break through the separator 8 or the like and come into contact with the positive electrode plate 3.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. The examples shown below do not specify the materials to be used, the tab shape, etc., as described below, but various modifications can be made based on the scope described in the claims. Further, in this specification, for easy understanding of the claims, the numbers corresponding to the members shown in the examples are
It is added to the members shown in "Claims" and "Column for means for solving the problem". However, the members shown in the claims are not limited to the members of the embodiment.

Example First, a positive electrode plate mixture was manufactured as follows. The positive electrode mixture is 85 manganese dioxide.
Weigh 0g, artificial graphite 50g, and Kerichen Black 50g, mix for 30 minutes with a Raiki machine, and then TF
30 g of E (trifluoroethylene) was added and further mixed.

This mixture was processed into a sheet shape, and a lath plate of SUS304 was rolled by two sheets so as to sandwich (thickness 0.13 mm) and then cut to prepare a positive electrode plate 3 shown in FIG. .. The size of the positive electrode plate 3 is 230 mm in length and 26 mm in width.
× The thickness is 0.48 mm. The positive electrode plate mixture in the center is peeled off, and as shown in FIG. 2, the positive electrode current collecting tab 4 (SUS30
4, width 3 mm, length 30 mm, thickness 0.1 mm) was spot-welded, and the tab portion was covered with the glass tape 10 for protection. This was heated to 200 ° C. and dehydrated.

The negative electrode has a thickness of 0.1, as shown in FIG.
A negative electrode current collector tab 2 was attached and fixed to a negative electrode plate 1 made of lithium and having a length of 8 mm × a length of 180 mm × a width of 24 mm with a polyethylene terephthalate tape 11. The negative electrode current collecting tab 2 was an L-shaped tab made of Ni. This battery is characterized in that an L-shaped negative electrode current collecting tab 2 composed of a tangential extension 2A and an axial extension 2B is projected from the end of the negative electrode.

The positive electrode plate 3 and the negative electrode plate 1 are laminated so that a polypropylene separator 8 is interposed therebetween, and this is wound to obtain an electrode winding product 5 shown in FIGS. 12 and 13. In the wound-up electrode product 5, the winding end portion of the negative electrode plate 1 is located inside the winding end portion of the positive electrode plate 3, and the L-shaped negative electrode current collecting tab 2 projects from the end of the negative electrode plate 1. The negative electrode current collecting tab 2 connects the tangential extension 2A to the negative electrode plate 1 and the axial extension 2B to the outer can. Tangent extension 2 connected to negative plate 1
A is extended from the winding end end of the negative electrode plate 1 in the winding direction and is taken out to the outer surface of the electrode wound product 5. The axial extension 2B is extended in the axial direction of the electrode winding product 5 on the outer surface of the electrode winding product 5 and protrudes from the lower end of the electrode winding product 5, and further, the corner of the lower end of the electrode winding product 5 is formed. Exterior can 9 bent at the corner
Connected to.

This electrode winding product 5 is taped with iron-N
Put it in an i-plated outer can and put the negative electrode collector tab 2 on the bottom of the can.
Each of the positive electrode current collecting tabs 4 was spotted on the sealing body, the electrolytic solution was injected, and then caulking and battery assembly were performed through polypropylene packing. The size of the finished battery is 1 diameter
The height was 6.6 mm and the height was 33.5 mm. In this organic electrolyte battery, the negative electrode current collector tab was not broken even when vibration was applied.

This battery was subjected to forced discharge at 1.5 A to make it over-discharged, and the occurrence of lithium deposition on the positive electrode plate was examined. No lithium deposition was observed.

[Comparative Example 1] In order to compare the characteristics of the organic electrolyte batteries manufactured in the examples, a battery having a conventional structure for taking out the negative electrode current collecting tab was manufactured as follows. In this battery, the outermost circumference of the electrode winding product was used as a negative electrode plate, and a negative electrode current collecting tab was connected to this negative electrode plate.

The positive electrode plate mixture was formed into the shape shown in FIG. 2 in the same manner as in the example, and the length was 230 mm × width 26 mm × thickness 0.
A positive electrode plate 3 having a size of 46 mm is formed, the center thereof is peeled off, and a positive electrode current collecting tab 4 (SUS304, width 3 mm, length 30 mm,
(Thickness 0.1 mm) was connected by spot welding, and the tab portion was covered with the glass tape 10 to protect it. 200 this
It was heated to ℃ and dehydrated.

The negative electrode has a thickness of 0.18 as shown in FIG.
A negative electrode current collector tab 2 made of Ni was adhered and fixed to a negative electrode plate 1 made of lithium and having a size of mm × length 210 mm × width 24 mm with a glass tape 7 to prepare the negative electrode current collector tab 2. The thickness of the positive electrode was reduced in order to adjust the outer diameter of the rolled electrode 5 with the outermost periphery as the negative electrode. This negative electrode plate 1 was laminated on the positive electrode plate 3 with a polypropylene separator 8 interposed therebetween and wound up to obtain an electrode wound product 5 shown in FIG.

In this organic electrolyte battery, the negative electrode plate 1 is positioned via a separator 8 so as to cover the outer side of the winding end portion of the positive electrode plate of the wound electrode wound product, and the outermost lithium of the negative electrode plate 1 is placed. It is characterized in that the negative electrode current collecting tab 2 is connected to.

The electrode winding product was taped and placed in an iron-Ni plated outer can 9 having a diameter of 16.5 mm and a height of 33.5 mm, and the battery was assembled into the same size as in the embodiment. I went.

This battery was subjected to forced discharge at 1.5 A to make it over-discharged and examined for lithium deposition on the positive electrode plate. A large amount of lithium deposit 6 was observed on the positive electrode plate, which was recognized to be inconvenient for battery safety.

Comparative Example 2 Further, an organic electrolyte battery having a conventional structure having another structure was manufactured as a prototype. In this organic electrolyte battery, the outermost periphery of the electrode wound product was used as the positive electrode plate, and the negative electrode current collector tab was connected to the negative electrode plate on the inner side of the winding end of the positive electrode plate of the electrode wound product.

The positive electrode plate mixture was the same as in the example and had a length of 2
A positive electrode plate 3 having a shape shown in FIG. 2 having a size of 30 mm × width 26 mm × thickness 0.46 mm is made, the central portion thereof is peeled off, and a positive electrode current collecting tab 4 (SUS304, width 3 mm, length 30 m).
m, thickness 0.1 mm) was spot-welded, and the tab portion was covered with the glass tape 10 for protection. This was heated to 200 ° C. and dehydrated.

The negative electrode has a thickness of 0.18 as shown in FIG.
The negative electrode plate 1 made of lithium and having a size of mm × length 210 mm × width 24 mm was used. This negative electrode plate 1 is provided with a negative electrode current collecting tab 2 made of Ni.
Was attached and fixed with glass tape 7. Since the positive electrode plate is arranged on the outermost periphery of the electrode wound product, it is necessary to reduce the thickness of the positive electrode plate in order to adjust the winding outer diameter. This negative electrode plate is wrapped with a polypropylene separator and wound up together with the positive electrode plate.
Shown in. The negative electrode current collecting tab 2 is connected to the negative electrode plate 1 inside the winding end portion of the positive electrode plate 3.

The negative electrode current collecting tab 2 is not broken immediately after the battery is assembled. However, when vibration is applied, the positive electrode plate 3 and the negative electrode current collecting tab 2 contact by breaking through the glass tape 7 of the negative electrode current collecting tab 2 and the separator 8 as shown in FIG.
The occurrence of an internal short circuit was confirmed. Reference numeral 12 denotes an insulating plate that prevents a short circuit between the positive electrode plate 3 and the outer can 9, but the cover of the outermost positive electrode plate 3 is only the separator 8 and is inevitably incomplete.

The discharge characteristics of the organic electrolyte batteries produced in Examples and Comparative Examples 1 and 2 were measured. The result is shown in the graph of FIG. As shown in this figure, the capacity of the battery of the present invention was not reduced as compared with the comparative example. This graph shows that the outside air temperature is 25 ° C and the load resistance is 20
It was set to 0Ω.

[0034]

EFFECTS OF THE INVENTION The organic electrolyte battery of the present invention eliminates the drawback that an active material such as lithium remaining on the negative electrode plate is deposited on the positive electrode plate to cause internal short circuit when forcedly discharged.
It is also possible to prevent the negative electrode current collector tab from being bent and contacting the positive electrode plate. The reason why the active material of the negative electrode plate does not deposit on the positive electrode plate is
This is because the organic electrolyte battery of the present invention uses the positive electrode plate at the outermost periphery of the wound electrode product. In a battery in which the outermost periphery of the electrode roll is the positive electrode plate, the active material of the negative electrode plate can be consumed up to the vicinity of the outer periphery while the battery is completely discharged, so that the active material remains on the negative electrode plate. It does not deposit on the plate.

Furthermore, in the organic electrolyte battery of the present invention, the negative electrode current collecting tab has a unique structure, so that the drawback that the negative electrode current collecting tab is bent at the bottom of the outer can and contacts the positive electrode plate is eliminated. That is, the organic electrolyte battery of the present invention,
The negative electrode current collector tab is composed of a tangential extension and an axial extension.The tangential extension is extended from the winding end of the negative electrode plate in the winding direction and taken out to the outer surface of the electrode winding product, and then axially extended. The extension is extended on the outer surface of the electrode winding product in the axial direction of the electrode winding product to protrude from the lower end of the electrode winding product, and the lower part of the axial extension is bent at the corner of the electrode winding product. Then, it is connected to the outer can along the electrode winding product. The organic electrolyte battery having this shape can be connected in a state in which the negative electrode current collecting tab is in close contact with the inner surface of the outer can without separating from the inner surface of the outer can. Therefore, it is possible to prevent a gap from being formed between the negative electrode current collecting tab and the outer can, and to prevent the negative electrode current collecting tab from being bent due to vibration or the like.

Therefore, the organic electrolyte battery of the present invention is
It is possible to eliminate the drawbacks of the active material being deposited on the positive electrode plate from the negative electrode plate to cause a short circuit and the negative electrode current collecting tab to be internally short-circuited, thereby providing a highly safe battery.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a wound electrode product incorporated in a conventional organic electrolyte battery.

FIG. 2 is a plan view of a positive electrode plate of the electrode winding product shown in FIG.

FIG. 3 is a plan view of a negative electrode plate of the electrode winding product shown in FIG.

FIG. 4 is a sectional view showing an example of a conventional organic electrolyte battery.

FIG. 5 is a cross-sectional view showing a charged state of a wound electrode product of a conventional organic electrolyte battery.

6 is a cross-sectional view showing a state in which a wound electrode of the organic electrolyte battery shown in FIG. 5 is completely discharged.

FIG. 7 is a cross-sectional view showing a charged state of a wound electrode product of a conventional organic electrolyte battery.

8 is a cross-sectional view showing a state in which a wound electrode of the organic electrolyte battery shown in FIG. 7 is completely discharged.

FIG. 9 is a plan view showing an example of a negative electrode plate used in a wound electrode product of a conventional organic electrolyte battery.

FIG. 10 is a sectional view showing an example of a conventional organic electrolyte battery.

FIG. 11 is a plan view showing a negative electrode plate and a negative electrode current collecting tab used in Examples.

FIG. 12 is a perspective view showing the manufacturing process of the electrode winding product used in the embodiment.

FIG. 13 is a perspective view of an electrode winding product used in the embodiment.

FIG. 14 is a graph showing discharge characteristics of examples and comparative examples.

[Explanation of symbols]

1 ... Negative electrode plate 2 ...
Negative electrode current collecting tab 2A ... tangential extension 2B
... Axial extension 3 ... Positive electrode plate 4 ...
Positive electrode current collecting tab 5 ... Electrode winding product 6 ...
Lithium deposition 7 ... Glass tape 8 ...
Separator 9 ... Exterior can 10 ...
Glass tape 11 ... Polyethylene terephthalate tape 12
Insulation plate 13 Insulation packing 14
… Sealed body

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Katsuya Motoya 2-18 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (1)

[Claims] 1. A negative electrode plate (1) and a positive electrode plate (3) are separators.
In an organic electrolyte battery in which an electrode winding product (5) stacked via (8) and wound in a spiral shape is housed in an outer can, the negative electrode plate (1) is placed on the outermost periphery of the electrode winding product (5). ) Is arranged so as to cover the positive electrode plate (3), and the negative electrode current collecting tab (2) connected to the negative electrode plate (1) has a tangential extension part (2A) and an axial extension part.
(2B), the tangential extension (2A) on the negative electrode plate (1),
The axial extension (2B) is connected to the outer can and the negative plate
The tangential extension (2A) connected to (1) extends in the winding direction from the winding end of the negative electrode plate (1) and is taken out to the outer surface of the electrode winding product (5). The direction extension portion (2B) extends in the axial direction of the electrode winding product (5) on the outer surface of the electrode winding product (5) and protrudes from the lower end of the electrode winding product (5). ) The organic electrolyte battery is characterized in that it is bent at the lower corner and connected to the outer can.