JPH11111325A - Cylindrical secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical secondary battery by through which positive and negative electrode plates can be wound up with high accuracy, having no rolling gap and the number of winding times can be reduced to achieve a speedup of winding up the positive and negative electrode plates, in various battery diameters over a wide range from small to large. SOLUTION: A spirally wound electrode body 1 is provided, in which a positive electrode plate 2, wherein a positive electrode active material layer is formed on both sides of a belt-like positive electrode current collector, and a negative electrode plate 3, wherein a negative electrode active material layer is formed on both sides of a belt-like negative electrode current collector, are wound spirally via a belt-like separator. The electrode body 1 is made to have a structure, in which a sheet of the positive electrode plate 2 and a sheet of the negative electrode plate 3 are bent in the respective longitudinal directions and combined to bite each other via the separator and are wound in this combined state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cylindrical secondary battery, and more particularly, to an electrode structure of a cylindrical secondary battery.

[0002]

2. Description of the Related Art In recent years, batteries have been increased in size in order to be used as a drive power source for electric vehicles requiring a large output or as a medium for storing power. Therefore, the electrode area increases, and accordingly, in the case of a cylindrical secondary battery, the number of windings of the positive and negative electrodes increases in the manufacturing process of the spiral electrode body, and the winding time of the positive and negative electrodes increases. Growth is a problem.

As a typical spiral electrode body of this type of cylindrical secondary battery, as shown in JP-B-59-10536, one positive electrode plate and one negative electrode plate are separated from each other by a separator. It is a structure wound by being overlapped. When a battery having such a structure is applied to a large cylindrical secondary battery having a large output power, the number of windings of the positive / negative electrode plate increases, and the winding speed cannot be increased.

In order to solve such a problem, a cylindrical secondary battery disclosed in Japanese Patent Publication No. 61-31594 has been proposed. In this cylindrical secondary battery disclosed in Japanese Patent Publication No. 61-31594, each positive / negative electrode plate is bent in a U-shape in the width direction, and these positive / negative electrode plates are combined in a meshing state. The spiral electrode body is manufactured by spirally winding in a state. Accordingly,
As compared to the case where one positive electrode plate and one negative electrode plate are stacked and wound as shown in JP-A-10-536, the number of windings is reduced by half, and the speed of winding the positive and negative electrode plates is increased. Can be achieved.

[0005]

However, since the conventional cylindrical secondary battery has a structure in which the positive and negative electrode plates bent in a U-shape are wound up, for example, when the battery diameter becomes 2 cm or more, the positive and negative When the plates are wound, tensile stress is generated on the positive and negative electrode plates to cause winding deviation, and it becomes difficult to wind the plates accurately. Also, if you forcibly wind it up,
The positive / negative electrode plate is partially distorted, and the active material is peeled off at that portion.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is intended to accurately wind a positive / negative electrode plate in a battery having a wide range of battery diameters, from small to large, without any winding deviation. It is an object of the present invention to provide a cylindrical secondary battery capable of reducing the number of windings and increasing the speed of winding the positive and negative electrode plates.

[0007]

Means for Solving the Problems To achieve the above object, a cylindrical secondary battery of the present invention comprises: a positive electrode plate having a positive electrode active material layer formed on both sides of a positive electrode current collector; A negative electrode plate in which a negative electrode active material layer is formed on both surfaces of a negative electrode current collector, and a cylindrical secondary battery including a spiral electrode body spirally wound via a band-shaped separator; Is characterized in that a plurality of positive electrode plates and negative electrode plates are stacked and wound so that the positive electrode plates and the negative electrode plates are alternately arranged with a separator interposed therebetween.

[0008] According to the above configuration, since a plurality of positive and negative electrode plates are superposed and wound, the number of windings is reduced, and the speed of winding the positive and negative electrode plates can be increased. As a result, productivity is improved. This effect is particularly remarkable in a large battery having a large number of turns. In addition, even when the battery diameter is large, the conventional cylindrical secondary battery (Japanese Patent Publication No.
(Battery described in JP-A-31594), the problem of occurrence of winding deviation and separation of the active material is also solved, and the positive and negative electrode plates can be wound accurately without any winding deviation. Even if the present invention is applied to a battery having a small current collector, such as a lithium ion battery having a small thickness, the number of windings can be reduced, and furthermore, it is possible to perform winding accurately with no winding deviation. Of course.

According to a second aspect of the present invention, in the cylindrical secondary battery according to the first aspect, at least one of the plurality of positive and negative electrode plates constituting the spirally wound electrode body is wound. Characterized by being fixed at the beginning

If the winding is fixed at the start end, the winding of the positive and negative electrode plates can be performed more smoothly. In addition, since one pole is wrapped in the other pole at the end of the winding start, the area of the counter electrode is increased in that part, and the electrode utilization efficiency is improved.

A third aspect of the present invention provides a positive electrode plate in which a positive electrode active material layer is formed on both sides of a strip-shaped positive electrode current collector, and a negative electrode in which a negative electrode active material layer is formed on both sides of a strip-shaped negative electrode current collector. In a cylindrical secondary battery having a spirally wound electrode body in which a plate is spirally wound via a strip-shaped separator, the spirally wound electrode body has a positive electrode plate and a negative electrode plate, each of which is bent in its longitudinal direction. , Are interlocked with each other via a separator, and are wound in this combined state.

According to the above configuration, in addition to the function and effect of the second aspect of the present invention, one end plate is also wrapped in the other end plate at the winding end portion of the spiral electrode body. As a result, the area of the counter electrode increases accordingly, and the efficiency of use of the electrodes can be increased.

According to a fourth aspect of the present invention, in the cylindrical secondary battery according to any one of the first to third aspects, a positive electrode plate and a separator are provided at one end of the spiral electrode body in the height direction. A negative electrode plate and a separator are formed so as to protrude from the negative electrode plate, and at the other end in the height direction of the spiral electrode body, are formed so as to protrude from the positive electrode plate, and a current collecting tab is provided at the one end at the height direction. The current collection tab has a bridging portion bridged between each end of the inner circumferential portion and the outer circumferential portion of the positive electrode plate facing each other via the negative electrode plate, and one end is connected to the bridging portion and the other end is connected to the bridging portion. A connection portion connected to an external terminal.

According to the above configuration, it is possible to collect power from two places on the positive electrode plate with one current collecting tab, and the current collecting effect is improved. In addition, at one end in the height direction of the spiral electrode body, the positive electrode plate and the separator are formed so as to protrude from the negative electrode plate, so that a short circuit between the current collecting tab and the negative electrode plate is prevented.

According to a fifth aspect of the present invention, in the cylindrical secondary battery of the fourth aspect, the current collection tab is provided before the positive and negative electrode plates are wound.

According to the above construction, when the positive and negative electrode plates are wound, there is no gap between the electrode plates and the positive and negative electrode plates can be smoothly wound. As a result, workability is improved. Can be improved.

According to a sixth aspect of the present invention, there is provided a cylindrical secondary battery according to any one of the second to fifth aspects,
The spiral electrode body is characterized in that it is wound so that the winding start is a positive electrode and the winding end is a negative electrode.

In the battery controlled by the positive electrode and the negative electrode, the positive and negative electrodes at the winding start end and the winding end are combined with the configuration according to claim 2 or 3 in addition to the configuration of the positive electrode at the beginning of winding and the negative electrode at the end of winding. Use efficiency is improved.

According to a seventh aspect of the present invention, in the cylindrical secondary battery according to any one of the first to sixth aspects, the outermost periphery of the spiral electrode body is a negative electrode.

According to the above configuration, since the outermost periphery of the spirally wound electrode body is the negative electrode, current collection on the negative electrode side from the side surface of the battery can becomes possible.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIGS. 1 to 8 show a first embodiment of the present invention.
This will be described below based on In FIGS. 2, 3, 4, and 8, the separators are indicated by broken lines for easy understanding. FIG. 1 is an exploded perspective view showing a structure of a main part of a cylindrical secondary battery according to the present invention. In FIG. 1, the separator is omitted for easy understanding. The spiral electrode body 1 has a structure in which a positive electrode plate 2 and a negative electrode plate 3 are spirally wound via a separator 4 (see FIGS. 2 and 3). As clearly shown in FIG. 5, the positive electrode plate 2 has a configuration in which a positive electrode active material layer 2b is formed on both sides of a strip-shaped positive electrode current collector 2a, and the negative electrode plate 3 has a structure in which a strip-shaped negative electrode current collector 3a is formed. The negative electrode active material layer 3b is formed on both surfaces. Although the electrode body 1 is shown to be wound about twice in the drawing, this is for easy understanding, and the number of windings is not particularly limited.

At the upper end of the spiral electrode body 1 in the height direction,
A positive electrode current collecting tab 5 is provided, and a negative electrode current collecting tab 6 is provided on the lower end side in the height direction of the spiral electrode body 1. As shown in FIGS. 2 and 4, the positive electrode current collection tab 5
A bridging portion 5 bridged between the outer circling portion and the inner circulating portion of the positive electrode plate 2 facing each other via the negative electrode plate 3 and the separator 4
a and a connecting portion 5b formed integrally with the bridge portion 5a
Consisting of Similarly to the positive electrode current collecting tab 5, the negative electrode current collecting tab 6 also has the negative electrode plate 3 opposed thereto via the positive electrode plate 2 and the separator 4.
A bridging portion 6a bridged between the outer and inner circling portions of the first and second connecting portions 6 formed integrally with the bridging portion 6a
b. The bridge portions 5a, 6a and the respective ends of the positive and negative electrode plates 2, 3 are welded by spot welding. Further, in the positive electrode current collecting tab 5, the tip of the connecting portion 5 b is welded to the battery can lid 10 by spot welding, and in the negative electrode current collecting tab 6, the tip of the connecting portion 6 b is spotted on the bottom surface 11 of the battery can. Welded by welding. The current collecting tabs 5 and 6 are welded to the positive and negative electrode plates 2 and 3 before the positive and negative electrode plates 2 and 3 are wound. Therefore, as described later, the positive and negative electrode plates 2 and 3 can be smoothly wound. Furthermore, by providing the current collecting tab in this way,
Current can be collected from two locations, an outer circumference portion and an inner circumference portion of each electrode plate.

As shown in FIG. 4, the upper ends of the positive electrode plate 2 and the separator 4 protrude above the upper end of the negative electrode plate 3 at the upper end of the spiral electrode body 1 in the height direction. On the lower end side in the height direction of the spiral electrode body 1, the lower ends of the negative electrode plate 3 and the separator 4 are formed to protrude below the lower end of the positive electrode plate 2. Further, an insulating layer 7 is formed on the upper surface of the negative electrode plate facing the positive electrode current collecting tab 5 and on the lower surface of the positive electrode plate facing the negative electrode current collecting tab 6, respectively. With such a step structure of the positive and negative electrode plates and an insulating structure of the end surfaces of the positive and negative electrode plates, the positive current collecting tab 5 and the negative electrode plate 3 are formed.
And the short-circuit between the negative electrode current collecting tab 6 and the positive electrode plate 2 is prevented.

Incidentally, the bridging portion 6a of the negative electrode current collecting tab and the positive electrode plate 2
Of the positive electrode current collector tab and the gap with the lower end face of the positive electrode current collector tab
When the distance between the positive electrode and the upper end surface of the negative electrode plate 3 is small, the above-described insulating structure of the positive and negative electrode plate end surfaces is necessary. However, when the distance is large, it may be omitted. Further, instead of the insulating structure on the end surfaces of the positive and negative electrode plates, the bridging portion 5a of the positive current collecting tab
And the upper surface of the bridging portion 6a of the negative electrode current collecting tab may be partially insulated.

The structure of the spiral electrode body 1 will be described in detail with reference to FIG. 3. At the winding start end of the spiral electrode body 1, the negative electrode plate 3 is wrapped in the positive electrode plate 2. At the end of winding, the positive electrode plate 2 is wrapped in the negative electrode plate 3. Therefore, the area of the dominant pole facing the positive electrode at the winding start end and the winding end end increases, and the utilization efficiency of the positive electrode is good. The outermost periphery of the spiral electrode body 1 is a negative electrode plate. Therefore, in the case of a battery of a type in which the side surface of the battery can has conductivity, such as a nickel-metal hydride storage battery, the negative electrode current collecting tab 6 can be omitted because the negative electrode side can be collected from the side surface of the battery can. May be.

Although one positive electrode current collecting tab 5 is provided, a plurality of positive electrode current collecting tabs 5 may be provided in the circumferential direction of the electrode body 1 as shown in FIG. 6, or as shown in FIG. The bridging portion 5a extending in the radial direction of the electrode body 1 may be configured to collect current from three or more circumferential portions of the positive electrode plate. By doing so, the current collection effect can be further enhanced. However, in the configuration of FIG. 6, if the current collecting tab is fixed before winding the positive and negative electrode plates, it becomes difficult to wind the current collecting tab. In this case, the current collecting tab should be fixed after winding. desirable. 6 and 7, the negative electrode plate and the separator are omitted for easy understanding.

On the other hand, in the case of the negative electrode current collecting tab 6, basically only one is provided. This is due to the difficulty in the operation of spot welding the negative electrode current collecting tab to the bottom surface of the battery can.

Here, iron, stainless steel, nickel, aluminum or the like can be used as the positive electrode current collector 2a, and iron, stainless steel, nickel, copper or the like can be used as the negative electrode current collector 3a. In addition, as the positive electrode active material, when using an alkaline battery, nickel hydroxide is used,
When a lithium battery is used, LiCoO ₂ , LiNi
O ₂ , LiMn ₂ O _4, etc. can be used, and as the negative electrode active material, a hydrogen storage alloy or cadmium hydroxide is used in the case of an alkaline battery, and natural graphite and other carbon materials are used in the case of a lithium battery. be able to. In addition, iron, stainless steel, nickel, aluminum, or the like can be used as the positive electrode current collecting tab 5, and iron, stainless steel, nickel, copper, or the like can be used as the negative electrode current collecting tab 6. Further, as the separator 4, porous polyethylene or polypropylene or the like can be used.

Next, a method of manufacturing the cylindrical secondary battery having the above structure will be described. First, as shown in FIG. 8, one positive electrode plate 2 and one negative electrode plate 3 are previously bent in the longitudinal direction. In consideration of the curvature in the state where the positive and negative electrode plates 2 and 3 are wound, the positive electrode plate and the negative electrode plate are bent so that the outer part is longer and the inner part is shorter in the wound state. Keep it. Next, the bent positive electrode plate 2 and the bent negative electrode plate 3 are engaged with each other via a separator 4 so as to be engaged with each other. The negative electrode current collecting tab 6 is spot-welded with a play to the lower end surface of the negative electrode plate 3 with play. By providing the current collecting tabs 5 and 6 before winding as described above, the positive / negative electrode plates are not separated, so that winding can be performed without winding deviation, and workability is improved.

Next, the winding core 13 is inserted near the inside of the bent portion of the positive electrode plate 2, and the positive electrode plate and the negative electrode plate are wound in the winding direction 15 where the outermost periphery of the electrode body 1 becomes the negative electrode plate 3. . By using the positive end at the winding start end in this way, in a battery dominated by the positive electrode, the utilization efficiency of the positive electrode can be increased. After winding the electrode plate to produce the spirally wound electrode body 1, the spirally wound electrode body 1 is housed in a battery can, the negative electrode current collecting tab 6 is spot-welded to the bottom surface 11 of the battery can, and the positive electrode current collecting tab 5 is fastened to the battery. By spot welding to the can lid 10, a cylindrical secondary battery is manufactured.

The above-mentioned spiral electrode body has a structure in which one positive electrode plate and one negative electrode plate are each bent in the longitudinal direction and wound, but a plurality of positive and negative electrode plates are formed. Each may be folded in the longitudinal direction and wound. In this case, at least one of the winding start end and the winding end may be fixed in advance, so that the winding can be performed more smoothly. When one of the winding start end and the winding end is fixed, it is desirable to fix the winding start end.

(Second Embodiment) As a second embodiment of the cylindrical secondary battery of the present invention, as shown in FIG. 9, a plurality of positive plates 2 and negative plates 3 are interposed via a separator 4. The positive electrode plate 2 and the negative electrode plate 3 may be alternately stacked and wound to manufacture a spiral electrode body.

(Third Embodiment) As a third embodiment of the cylindrical secondary battery of the present invention, as shown in FIG. 10, one end of each of a plurality of positive plates 2 is spot-welded in advance. One end of each of the plurality of negative electrode plates 3 is spot welded and fixed in advance, and each of the plurality of positive electrode plates 2 and the negative electrode plates 3 is combined in a meshing state. The body 1 may be manufactured. Furthermore, only the ends of each of the plurality of positive plates 2 may be fixed, and the ends of each of the plurality of negative plates 3 may be wound without being fixed to manufacture a spiral electrode body.

The cylindrical secondary battery of the present invention can be applied to alkaline batteries, lithium ion batteries, and other various types of batteries. You.

[0035]

【Example】

EXAMPLE As an example, a nickel-metal hydride storage battery having the structure shown in the first embodiment was used. Battery diameter,
The following dimensions were used for the positive electrode plate, the negative electrode plate, the hydrogen storage alloy electrode, and the separator. Battery diameter: 34 mm Positive electrode plate: thickness 0.60 mm, vertical length 50 mm, horizontal length 46
0 mm negative electrode plate: thickness 0.42 mm, vertical length 50 mm, horizontal length 60
0mm separator: Thickness 0.15mm, vertical and horizontal are positive.
The dimensions of the positive electrode plate, the negative electrode plate, and the separator of each battery having a battery diameter of 26 mm, 30 mm, and 43 mm were the same as those of the battery having the diameter of 30 mm. The battery having such a structure is hereinafter referred to as Battery A of the present invention.

COMPARATIVE EXAMPLE As a comparative example, as shown in Japanese Patent Publication No. 59-10536, an electrode body was formed by winding one positive electrode plate and one negative electrode plate with a separator interposed therebetween. A battery similar to the example was used except that the battery had a structure. A battery having such a structure is hereinafter referred to as a comparative battery X.

[Experiment 1] Battery A of the present invention and Comparative Battery X
Table 1 shows the relationship between the battery diameter and the energy density. In this experiment, the battery was charged at a current of 0.1 C for 16 hours under the battery conditions shown in Table 2, and then charged.
The comparison was made based on the discharge capacity when the battery was discharged until the battery voltage reached 1.0 V.

[0038]

[Table 1]

[0039]

[Table 2]

As is clear from Table 1, in the battery having a diameter of less than 30 mm, the output density of the battery A of the present invention is smaller than that of the comparative battery X. This is presumably because the battery A of the present invention has a lower energy density than the comparative battery X because it is difficult to wind the positive and negative electrode plates in a state close to a perfect circle. On the other hand, in the battery having a diameter of 30 mm or more, it is recognized that the battery A of the present invention has a higher output density than the comparative battery X. This is because, in the battery A of the present invention, since the poles are wrapped at the start and end of winding, the facing area of the positive electrode is increased, and the energy density loss due to the non-roundness is smaller than the loss of the energy density. This is considered to be because the effect of the utilization efficiency of the positive electrode appears stronger.

According to the experimental results, it is considered that it is not appropriate to apply the present invention to a battery having a diameter of less than 30 mm. However, even in the case of a battery having a diameter of less than 30 mm, the effect that the effect of the use efficiency of the positive electrode appears more strongly may be exhibited depending on the type of battery, the thickness of the electrode plate, the length of the electrode plate, and the like. It is also possible to wind the positive and negative electrode plates in a state close to a perfect circle. Therefore, the present invention can be applied to a wide range of batteries from small-diameter batteries to large-diameter batteries in consideration of the type of battery, the thickness of the electrode plate, the length of the electrode plate, and the like.

[0042]

According to the present invention as described above,
Since the number of windings of the positive and negative electrode plates is reduced, the speed of winding the positive and negative electrode plates is increased, and as a result, productivity can be improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a structure of a main part of a first embodiment of a cylindrical secondary battery according to the present invention.

FIG. 2 is a view near a positive electrode current collecting tab.

FIG. 3 is a view of the spiral electrode body as viewed from above.

FIG. 4 is a longitudinal sectional view of a spiral electrode body.

FIG. 5 is a partially enlarged longitudinal sectional view of a spiral electrode body.

FIG. 6 is a view showing another embodiment of the positive electrode current collecting tab.

FIG. 7 is a view showing another embodiment of the positive electrode current collection tab.

FIG. 8 is a view of a state before winding the positive and negative electrode plates as viewed from above.

FIG. 9 is a diagram schematically illustrating a state before winding of positive and negative electrode plates according to a second embodiment of the present invention.

FIG. 10 is a diagram schematically illustrating a state before winding of positive and negative electrode plates according to a third embodiment of the present invention.

[Explanation of symbols]

 1: spiral electrode body 2: positive electrode plate 2a: positive electrode current collector 2b: positive electrode active material layer 3: negative electrode plate 3a: positive electrode current collector 3b: positive electrode active material layer 4: separator 5: positive electrode current collector tab 5a: cross-linked portion 5b: connecting part

Continuation of the front page (72) Inventor Koichi Sato 2-5-2-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Katsuhiko Niiyama 2-5-5-1 Keihanhondori, Moriguchi-shi, Osaka Within Sanyo Electric Co., Ltd. (72) Inventor Ikuro Yonezu 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Prefecture Inside Sanyo Electric Co., Ltd. (72) Koji Nishio 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd.

Claims (7)

[Claims] 1. A positive electrode plate having a positive electrode active material layer formed on both sides of a belt-shaped positive electrode current collector and a negative electrode plate having negative electrode active material layers formed on both surfaces of a band-shaped negative electrode current collector are formed into a band-like shape. In a cylindrical secondary battery provided with a spiral electrode body spirally wound through a separator, the spiral electrode body comprises a plurality of positive electrode plates and a plurality of negative electrode plates, and a positive electrode plate and a negative electrode plate Characterized in that the cylindrical secondary battery has a structure in which it is wound so as to be alternately stacked. 2. The method according to claim 1, wherein at least one of the plurality of positive electrode plates and the negative electrode plate constituting the spiral electrode body is fixed at a winding start end. Cylindrical secondary battery. 3. A positive electrode plate having a positive electrode active material layer formed on both sides of a belt-shaped positive electrode current collector and a negative electrode plate having negative electrode active material layers formed on both surfaces of a band-shaped negative electrode current collector are formed in a band shape. In a cylindrical secondary battery including a spirally wound electrode body wound spirally through a separator, the spirally wound electrode body has a positive electrode plate and a negative electrode plate, each of which is bent in the longitudinal direction thereof, and is mutually separated via the separator. A cylindrical secondary battery which is combined in an engaged state and has a structure wound in this combined state. 4. A positive electrode plate and a separator are formed so as to protrude from a negative electrode plate at one end in a height direction of the spiral electrode body, and at the other end in a height direction of the spiral electrode body,
A negative electrode plate separator is formed so as to protrude from the positive electrode plate. Further, a current collecting tab is provided on one end side in the height direction, and the current collecting tab is turned around the inside of the positive electrode plate facing the negative electrode plate. A bridge having a bridging portion bridged between the ends of the portion and the outer circumferential portion, and a connecting portion having one end connected to the bridging portion and the other end connected to an external terminal. Item 4. A cylindrical secondary battery according to any one of Items 3. 5. The cylindrical secondary battery according to claim 4, wherein the current collecting tab is provided before winding the positive and negative electrode plates. 6. The cylindrical mold according to claim 2, wherein the spiral electrode body is wound so that a winding start is a positive electrode and a winding end is a negative electrode. Rechargeable battery. 7. The cylindrical secondary battery according to claim 1, wherein an outermost periphery of the spiral electrode body is a negative electrode plate.