JP3213370B2 - Organic electrolyte battery - Google Patents

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 improved safety by improving a structure for taking out a negative electrode current collecting tab.

[0002]

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

[0003] 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 collection tab projects, and the lower side is the axis of the negative electrode current collection tab. It shall mean the direction in which the direction extension projects.

[0004]

[Problems to be solved by the invention] However, FIG.
In the battery having the structure of taking out the negative electrode current collecting tab 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 wound product 5 in an undischarged state. Since the outermost peripheral portion of the negative electrode plate 1 does not have the positive electrode plate 3 on the outer surface side, the discharge reaction occurs only from one side thereof. On the other hand, since the both sides of the portion of the negative electrode plate 1 located inside the wound product 5 are opposed to 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, such as 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. Faster. In the completely discharged state, as shown in the cross-sectional view of the wound electrode product 5 shown in FIG. 6, the outermost peripheral portion of the negative electrode plate 1 remains even when the portion located inside the negative electrode plate 1 is completely discharged. Will do. Further, in the state shown in FIG. 6, since the negative electrode current collecting tab 2 is still connected to the negative electrode plate 1 remaining on the outermost periphery of the electrode winding product 5, overdischarge may be further performed. At the time of this overdischarge, as shown in FIG. 1, on the surface of the positive electrode plate 3 opposite to the negative electrode plate 1 located at the outermost periphery, lithium precipitation 6 as a negative electrode active material occurs, and the deposited lithium grows to form a negative electrode. When the pressure reaches, there is a danger of an internal short-circuit and ignition of the battery.

Further, as shown in the enlarged view of FIG. 4, the take-out structure of the negative electrode current collecting tab is such that a part of the negative electrode current collecting tab 2 is bent and breaks through the glass tape 7 and the separator 8 to form the positive electrode plate 3. Touching, short, and possible ignition. For this reason, the structure for taking out the negative electrode current collection tab includes a short circuit and a potential problem of ignition. The present invention has been developed as a problem to prevent ignition due to a short circuit with a positive electrode plate due to a structure for taking out a negative electrode current collecting tab.

An organic electrolyte battery in which an outer can also serves as a positive electrode terminal does not have such a drawback. This is because the negative electrode current collecting tab can be taken out in the direction of the sealing body. As shown in FIG. 4, the battery has an annular inward protruding portion formed in the vicinity of an opening of a bottomed cylindrical outer can 9 containing the wound electrode product 5, and an insulating packing is formed on the inner protruding portion. The sealing body 14 is placed via the casing 13 and the opening of the outer can 9 is caulked. With such a structure, when the battery is vibrated, even if the electrode wound product 5 attempts to move upward, it comes into contact with the inner protruding portion of the outer can 9 and moves further upward. Can not. For this reason, the current collecting tab led out above the electrode winding product 5 does not bend greatly and may not cause an internal short circuit. If it is insulated from the positive electrode by a protective tape or the like, short-circuiting and inconvenience of ignition do not occur. Further, in order to prevent the wound product 5 of the electrode from shorting with the outer can 9, the width of the positive electrode plate 3 must be 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 used as the positive electrode. The polarity of the outer can needs to be adapted to the application.

In an organic electrolyte battery having an outer can as a negative electrode, it is necessary to take out a negative electrode current collecting tab in a direction toward the bottom of the can. 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 to the outermost periphery, the battery of this structure is overdischarged as described above. At this time, the active material of the negative electrode plate 1 located at the outermost periphery is deposited on the opposed positive electrode plate 3, and there is a high possibility that short-circuit or ignition may occur. In order to prevent this adverse effect, when the entire negative electrode is thinned so that the active material of the negative electrode plate is consumed at the end of the discharge, the battery discharge capacity is reduced by half.

This disadvantage can be solved by separating the negative electrode plate remaining on the outermost periphery from the negative electrode current collecting tab in a state where the battery is completely discharged. One example is shown in FIG. 7 and FIG. 7 is an end view of the wound product 5 showing a non-discharged state, and FIG. 8 shows a completely discharged state. Also,
As shown in FIG. 9, the negative electrode plate 1 uses a negative electrode current collecting tab 2 which is connected to the negative electrode plate 1 by being shifted from the end of the negative electrode plate 1 to the center. In the non-discharged 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 a completely discharged state, only the outermost negative electrode plate 1 remains, and the negative electrode plate 1 located inside the wound electrode product is not consumed, so that the negative electrode plate 1 positioned inside the wound electrode product 5 is not consumed. Is separated from the negative electrode plate 1 remaining on the outermost periphery. When the negative electrode plate 1 is cut off from the negative electrode current collecting tab 2 in this manner, the remaining active material of the negative electrode plate 1 is deposited on the surface of the positive electrode plate 3 and short-circuited without being over-discharged. Never.

[0009] However, the organic electrolyte battery incorporating the negative electrode plate of this structure has another adverse effect. That is, since the negative electrode plate having this structure moves the negative electrode current collecting tab 2 toward the center of the electrode winding product 5, the distance d between the negative electrode current collecting tab 2 and the outer can 9 is large as shown in FIG. Become. When the negative electrode current collecting tab 2 separates from the outer can 9, as shown in the figure, when the molded battery is vibrated, “bending” occurs in the negative electrode current collecting tab 2, and the bent portion breaks the separator 8. There is a problem that a short circuit is caused by contact with the positive electrode plate 3.

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.
If the negative electrode current collecting tab is shifted to the center side of the wound product of the electrode in order to avoid this defect, there is a defect that the negative electrode current collecting tab is bent and comes into contact with the positive electrode plate to cause a short circuit. "Overdischarge measures"
And there is no method that can solve both "tab bending"
It was an urgent task.

The present invention has been developed with the object of solving the conventional drawbacks. An important object of the present invention is to prevent an internal short circuit caused by a negative electrode current collector tab and to provide a highly safe organic electrolyte. It is to provide a battery.

[0012]

Means for Solving the Problems 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 battery having a structure in which an electrode wound product 5 in which a negative electrode plate 1 and a positive electrode plate 3 are laminated via a separator 8 and wound in a spiral shape is housed in an outer can. is there.

A positive electrode plate 3 is arranged at the outermost periphery of the wound electrode 5 so as to cover the negative electrode plate 1. Further, the negative electrode current collecting 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 taken out on 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. It is connected to a can 9.

[0014]

In the organic electrolyte battery according to the present invention, the outermost periphery of the wound electrode product 5 is the positive electrode plate 3. Therefore, no active material remains on the outer peripheral portion of the negative electrode plate 1 when the battery is completely discharged. In the completely discharged organic electrolyte battery, the active material of the negative electrode does not deposit on the positive electrode plate 3 and short-circuit inside the battery even when the battery is forcibly discharged.

The negative electrode current collecting tab 2 is extended to the outer surface of the electrode winding product 5 at a tangentially extending portion 2A. The axial extension 2B of the negative electrode current collection tab 2 has its lower end bent at the lower end of the electrode winding product 5 and connected to the outer can. The negative electrode current collecting tab 2 in this state is housed in close contact with the surface of the electrode winding product 5 so as not to be separated from the outer can. Negative electrode current collecting tab 2 approaching the outer can
Does not bend by 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. In the embodiments described below, the materials used, the tab shapes, and the like are not limited to those described below, and various modifications can be made based on the scope described in the claims. Further, in this specification, in order to make it easy to understand the scope of the claims, the numbers corresponding to the members shown in the embodiments will be described.
The members described in “Claims” and “Means for solving the problem” are added. However, the members described in the claims are not limited to the members of the embodiments.

Example First, a positive electrode plate mixture was produced as follows. For the positive electrode plate mixture, manganese dioxide
0 g, 50 g of artificial graphite and 50 g of Kelichen black were weighed and mixed for 30 minutes with a raikai machine, and then TF was added.
30 g of E (trifluoroethylene) was added and mixed.

This mixture was processed into a sheet shape, and a SUS304 lath plate was rolled between two sheets so as to sandwich (thickness: 0.13 mm), and then cut to produce a positive electrode plate 3 shown in FIG. . The dimensions of the positive electrode plate 3 are 230 mm long × 26 mm wide.
X The thickness is 0.48 mm. The central positive electrode plate mixture was 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 was covered with a glass tape 10 to protect it. 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 to a lithium negative electrode plate 1 having a size of 8 mm × length 180 mm × width 24 mm by a polyethylene terephthalate tape 11 and fixed. 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 collection tab 2 composed of a tangential extension 2A and an axial extension 2B is projected from an end of the negative electrode.

The positive electrode plate 3 and the negative electrode plate 1 are laminated such that a polypropylene separator 8 is interposed therebetween, and the resultant is rolled up to form a rolled-up electrode 5 shown in FIGS. In the wound electrode wound 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 protrudes from the end of the negative electrode plate 1. The negative electrode current collection tab 2 connects the tangential extension 2A to the negative electrode plate 1 and the axial extension 2B to the outer can. Tangential extension 2 connected to negative electrode 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 winding product 5. The axial extension 2 </ b> B extends on the outer surface of the electrode winding product 5 in the axial direction of the electrode winding product 5 and projects from the lower end of the electrode winding product 5, and further has a corner at the lower end of the electrode winding product 5. Outer can 9 folded at the corner
Linked to

The electrode wound product 5 is taped and iron-N
Put in an i-plated outer can, and place the negative electrode current collector tab 2 on the bottom of the can.
The positive electrode current collecting tabs 4 were spotted on the sealing body, and after injecting an electrolytic solution, caulking and battery assembly were performed via polypropylene packing. The size of the completed battery is 1
It became 6.6 mm and height was 33.5 mm. This organic electrolyte battery did not break the negative electrode current collecting tab even when subjected to vibration.

The battery was subjected to a forced discharge at 1.5 A, and was placed in an overdischarged state. The occurrence of lithium deposition on the positive electrode plate was examined, but no lithium deposition was observed.

Comparative Example 1 In order to compare the characteristics of the organic electrolyte battery prototyped in the example, a battery having a conventional negative electrode current collecting tab take-out structure was prototyped as follows. In this battery, the outermost periphery of the wound electrode was a negative electrode plate, and a negative electrode current collecting tab was connected to the negative electrode plate.

The positive electrode plate mixture was made into the shape shown in FIG. 2 in the same manner as in the example, and was 230 mm long × 26 mm wide × 0.1 mm thick.
A positive electrode plate 3 of 46 mm was made, and the center thereof was 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 a glass tape 10 and protected. This is 200
Heated to ° C. 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 attached to a negative electrode plate 1 made of lithium having a size of 210 mm × length 210 mm × width 24 mm with a glass tape 7 and fixed. The thickness of the positive electrode was reduced in order to adjust the winding outer diameter with the outermost periphery of the electrode wound product 5 as the negative electrode. This negative electrode plate 1 was laminated and wound on the positive electrode plate 3 with a polypropylene separator 8 interposed therebetween to obtain an electrode wound product 5 shown in FIG.

In this organic electrolyte battery, the negative electrode plate 1 is positioned with the separator 8 interposed therebetween so as to cover the winding end portion of the positive electrode plate of the wound electrode wound product. Is connected to the negative electrode current collecting tab 2.

This electrode wound product is taped and put in an iron-Ni plating outer can 9 having a diameter of 16.5 mm and a height of 33.5 mm, and assembling the batteries to the same dimensions as in the embodiment. Was done.

The battery was subjected to a forced discharge at 1.5 A, and was placed in an overdischarged state, and lithium deposition on the positive electrode plate was examined. A large amount of lithium deposit 6 was observed on the positive electrode plate, which was found to be inconvenient in terms of battery safety.

Comparative Example 2 Further, an organic electrolyte battery having another structure and a conventional structure was prototyped. In this organic electrolyte battery, the outermost periphery of the wound electrode product was a positive electrode plate, and a negative electrode current collecting tab was connected to a negative electrode plate inside the wound end portion of the wound electrode product from the end of the positive electrode plate winding.

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 formed, and a central portion thereof is peeled off to form 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 a glass tape 10 and protected. 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 was made of lithium and had a size of 210 mm × length 210 mm × width 24 mm. This negative electrode plate 1 is provided with a negative electrode current collecting tab 2 made of Ni.
Was fixed with a glass tape 7. In order to arrange the positive electrode plate on the outermost periphery of the wound electrode product, it is necessary to reduce the thickness of the positive electrode plate for adjusting the winding outer diameter. FIG. 4 shows the negative electrode plate wrapped in 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 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 collection tab 2 come into contact with each other by breaking and breaking through the glass tape 7 of the negative electrode current collection tab 2 and the separator 8 as shown in FIG.
The occurrence of an internal short was confirmed. Reference numeral 12 denotes an insulating plate for preventing 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 must be incomplete.

The discharge characteristics of the organic electrolyte batteries experimentally manufactured in Example and Comparative Examples 1 and 2 were measured. The results are shown in the graph of FIG. As shown in this figure, the battery of the present invention did not decrease in capacity as compared with the comparative example. This graph shows that the load resistance is 20
It was set to 0Ω.

[0034]

The organic electrolyte battery according to the present invention eliminates the disadvantage that active material such as lithium remaining on the negative electrode plate precipitates on the positive electrode plate and causes an internal short circuit when forcibly discharged.
The adverse effect that the negative electrode current collecting tab is bent and comes into contact with the positive electrode plate can also be prevented. The reason why the active material of the negative electrode plate does not precipitate on the positive electrode plate is that
This is because the outermost periphery of the wound electrode product is used as the positive electrode plate in the organic electrolyte battery of the present invention. In a battery in which the outermost periphery of the wound electrode is a positive electrode plate, the active material of the negative electrode plate can be consumed to the vicinity of the outer periphery in a state where the battery is completely discharged. It does not precipitate on the plate.

Furthermore, the organic electrolyte battery of the present invention eliminates the drawback that the negative electrode current collecting tab is bent at the bottom of the outer can and comes into contact with the positive electrode plate by having a unique structure for the negative electrode current collecting tab. That is, the organic electrolyte battery of the present invention,
The negative electrode current collecting tab is composed of a tangential extension and an axial extension, and the tangential extension is extended in the winding direction from the winding end end of the negative electrode plate and taken out on the outer surface of the electrode winding product, and is taken out in the axial direction. 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. And connected to the outer can along the electrode winding product. The organic electrolyte battery of this shape can be connected in a state of being in close contact with the negative electrode current collection tab without separating it 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 suppress bending of the negative electrode current collecting tab due to vibration or the like.

Therefore, the organic electrolyte battery of the present invention
The disadvantage that the active material is deposited on the positive electrode plate from the negative electrode plate to cause a short circuit and the negative current collector tab is bent to cause an internal short circuit can be eliminated, thereby providing a highly safe battery.

[Brief description of the drawings]

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

FIG. 2 is a plan view of a positive electrode plate of the wound electrode product shown in FIG. 1;

FIG. 3 is a plan view of a negative electrode plate of the wound electrode product shown in FIG. 1;

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 product of a conventional organic electrolyte battery.

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

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

8 is a cross-sectional view showing a state in which the wound product of the 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 for a wound electrode 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 an example.

FIG. 12 is a perspective view showing a manufacturing process of an electrode wound 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 an example and a comparative example.

[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 collecting tab 5 ... Electrode winding product 6 ...
Lithium deposition 7 ... Glass tape 8 ...
Separator 9 ... Outer can 10 ...
Glass tape 11 ... Polyethylene terephthalate tape 12
... insulating plate 13 ... insulating packing 14
… Sealing body

──────────────────────────────────────────────────続 き Continuation of the front page (72) Katsuya Motoya 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (56) References JP 5-101815 (JP, A) JP JP-A-2-51869 (JP, A) JP-A-59-111259 (JP, A) JP-A-1-106070 (JP, U) JP-A-1-106071 (JP, A) U) Japanese Utility Model 1-117059 (JP, U) Japanese Utility Model 2-70365 (JP, U) Japanese Utility Model 1-174854 (JP, U) Japanese Utility Model 1-1119161 (JP, U) Japanese Utility Model 3 -68356 (JP, U) Japanese Utility Model 1-81868 (JP, U) JP-B 46-37530 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 2/26 H01M 6/16 H01M 10/40

Claims (1)

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