JPH08264206A - Nonaqueous battery - Google Patents

Abstract

PURPOSE: To provide a lithium ion secondary battery capable of ensuring safety even if short circuit between a positive active material and a negative electrode is generated by abnormal heat from the outside, crush of the battery in the stacking direction, or piercing with a nail or the like. CONSTITUTION: Layer structure of an electrode plate stacking body is formed by stacking an insulating film 14, a positive electrode side current collector foil 11a, a positive active material 11b, a separator 13, a negative active material 12b, a negative electrode side current collector foil 12a, an insulating film 14, the positive electrode side current collector foil 11a... from a battery can side to the inside in order. Even when short circuit between the positive active material 11b and a negative electrode is generated, short circuit between the current collectors 11a, 12a is almost simultaneously generated, almost all current in the short circuit part flows to the current collectors 11a, 12a, and temperature rising in the positive active material (LiCoO2 ) 11b is suppressed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-aqueous battery. In particular, it relates to a non-aqueous battery having a specific structure for ensuring safety.

[0002]

2. Description of the Related Art A lithium ion secondary battery using a non-aqueous electrolyte is being adopted as a power source for portable electronic devices because of its high voltage, high capacity, high output and light weight. Such a lithium-ion secondary battery generally has a cylindrical electrode plate laminate, which is wound in a spiral shape with a porous resin film having a fine pore size interposed as a separator between a positive electrode plate and a negative electrode plate, to form a negative electrode. It is contained in a stainless steel battery can. An aluminum foil current collector coated with a material containing a lithium composite oxide (LiCoO ₂ etc.) as a positive electrode active material was used as the positive electrode plate, and a material containing carbon as a negative electrode active material was coated as the negative electrode plate. A copper foil current collector is used.

The electrode plate laminate for lithium ion secondary batteries currently in circulation is composed of one positive electrode plate having an active material coating on both sides of an aluminum foil and one positive electrode plate having an active material coating on both sides of a copper foil. A negative electrode plate and two separators, a negative electrode plate, a separator, a positive electrode plate, a separator are stacked in this order, and the negative electrode plate is wound on a spirally wound structure or an active material on both sides of the structure. Negative electrode plate with a coating, separator,
Two positive electrode plates with an active material coating on one side of the aluminum foil (the aluminum foil sides are placed side by side with the active material coating side facing outward), the separators are stacked in this order, and the negative electrode plate is on the outside. It has a structure obtained by spirally winding.

In such a lithium ion secondary battery,
In order to ensure safety when the temperature inside the battery rises due to short circuit between the positive electrode and negative electrode of the battery due to circuit abnormality or incorrect usage, a safety valve, temperature fuse, PTC element, etc. have been provided conventionally. However, further safety measures are required for various usage environments and unexpected accidents.

For example, when a sharp conductor such as a nail is stabbed in a battery can in an overcharged state, when it is abnormally heated from the outside, or when the battery is crushed in the stacking direction of the electrode plate stacks. As a result, it often causes a rapid temperature rise inside.

[0006]

It is clear that the short circuit between the positive electrode and the negative electrode occurs inside the battery in the above case, but it was not clear why the temperature rises rapidly inside the battery. The present inventors have found that such a phenomenon occurs due to the following causes, and have completed the present invention.

When a nail, which is a conductor, is inserted into the battery, the tip of the nail penetrates the battery can, which is the negative electrode, and contacts the internal positive electrode plate in the state where it becomes the negative electrode. Through the short circuit. Further, when the battery is abnormally heated from the outside, the separator, which is an organic material, first melts, so that the positive electrode plate and the negative electrode plate, which are insulated by the separator, come into contact with each other to cause a short circuit. Furthermore, when the battery is crushed in the stacking direction of the electrode plate laminate, a large stress is applied to the inner peripheral side of the electrode plate laminate, the separator is broken, and the positive electrode plate and the negative electrode plate come into contact with each other to cause a short circuit.

At the time of such a short circuit, the lithium composite oxide (positive electrode active material) has a relatively high resistance value among the members constituting the electrode plate laminate, so that the temperature of the lithium composite oxide is reduced by the passage of the short circuit current. Easy to rise. Then, the heat generated by this temperature rise easily causes the decomposition reaction of the organic solvent inside the battery. Further, when such a short circuit occurs in the battery in the charged state, the lithium composite oxide in the charged state is in an unstable state in which lithium is released as ions to some extent. Likely to happen. This oxygen facilitates the reaction of the aluminum foil and the organic solvent on which the lithium composite oxide is deposited.

According to the present invention, even if the battery is abnormally heated from the outside, a sharp conductor such as a nail is stabbed in the battery can, or the battery is crushed in the stacking direction of the electrode plate stack, To make a short circuit between the positive electrode active material and the negative electrode less likely to occur, or to suppress the temperature rise of the positive electrode active material accompanying this even if it occurs, to provide a non-aqueous battery that can ensure safety and To do.

[0010]

In order to solve the above-mentioned problems, the present invention provides a positive electrode plate having a positive electrode active material on only one side of a current collector foil and a negative electrode active material on only one side of the current collector foil. A negative electrode plate having, a separator, and an insulating film, and has an electrode plate laminated body in a battery can, the electrode plate laminated body, the surface having the positive electrode active material of the positive electrode plate and the negative electrode active material of the negative electrode plate. Provided is a non-aqueous battery in which unit battery layers whose surfaces are opposed to each other with a separator interposed therebetween are laminated with an insulating film interposed therebetween.

Specific examples of the method for producing the above electrode plate laminate include a method in which a unit battery layer and an insulating film are superposed and wound in a spiral shape by a winding machine (a winding type), or the unit battery layer is an insulating film. Examples of the method include a method of stacking in parallel with each other (simple stacking type), a method of stacking a unit battery layer and an insulating film stacked in parallel while folding back with a predetermined width (zigzag folding type), and the like.

In the structure of the non-aqueous battery of the present invention, the positive electrode active material surface and the negative electrode active material surface face each other with the separator interposed therebetween, and the positive and negative current collector foil surfaces having no active material sandwich the insulating film. Facing each other. Therefore, when a short circuit occurs between the positive electrode active material and the negative electrode due to abnormal heating from the outside, crushing in the stacking direction of the battery, or piercing with a nail, a short circuit occurs between the positive and negative current collector foil surfaces that do not have the active material. Also occurs. Since the resistance value of the current collector foil is lower than the resistance value of the positive electrode active material, the current mainly flows to the current collector foil having a low resistance value even in the short-circuited portion, and the current flowing to the positive electrode active material decreases. Therefore, abnormal temperature rise of the positive electrode active material can be suppressed at the time of short circuit.

In the non-aqueous battery of the present invention, the battery can is
It may be a substance that becomes a negative electrode, a substance that becomes a positive electrode, or a non-conductive substance such as a resin that is neither of them. When the battery can is made of a non-conductive material such as resin, the battery can can be provided with external electrodes. When the battery can serves as the negative electrode, it is preferable that the surface of the positive electrode plate having no active material faces the battery can through the insulating film. In this case, in the event of a nail stab accident, the tip of the nail penetrates the battery can, which is the negative electrode, and contacts the internal positive electrode plate in the state where it becomes the negative electrode, causing a short circuit. This is because, in the case of being put in, the tip always contacts the current collector foil before coming into contact with the positive electrode active material, so that almost no current flows through the positive electrode active material.

With this construction, in the wound type, the unit battery layer is wound with the positive electrode plate side facing outward, and an insulating film is wound at least on the outermost periphery of the unit battery layer to prepare an electrode plate laminate, which is then put into a battery can. Obtained by putting in. In the simple stacking type, for example, an electrode plate stack is manufactured by stacking a plurality of unit battery layers by facing the positive electrode plate side and the negative electrode plate side and sandwiching an insulating film therebetween, The negative electrode plate side is aligned with the center of the stacking direction, an insulating film is placed between at least both end surfaces of each unit battery layer and the battery can, and if necessary, the uppermost surface of the electrode plate laminate and the battery can In addition, it is obtained by disposing an insulating film between the lowermost surface and the battery can. In the zigzag fold type, an electrode plate laminate is produced by folding the unit battery layer so that the positive electrode plate side is arranged on the inner side surface parallel to the folded unit surface among the inner side surfaces of the battery can, and at least the above It is obtained by disposing an insulating film between the positive electrode plate arranged on the inner side surface and the inner side surface.

The current collector foils of the positive electrode plate and the negative electrode plate may be coated with the active material on one side or may be partially coated, but the active material is coated on the entire one side. Those which have been described are preferable because they are easily manufactured. In addition, it is necessary that the active material is not deposited on the other surface at all and the current collector surface is entirely exposed. Examples of the current collector foil for the positive electrode include metal foils such as aluminum, titanium and stainless steel, with aluminum being preferred. The thickness of the collector foil of the positive electrode is generally 5 to 100 μm, preferably 8 to 50 μm.
m, and more preferably 10 to 50 μm.

As the current collector foil for the negative electrode, there are metal foils such as copper, nickel and stainless steel, and copper and stainless steel are preferable. The thickness of the current collector foil of the negative electrode is generally 6 to 50 μm, preferably 8 to 25 μm. The shape of the collector foil of the positive electrode and the negative electrode may be an expanded metal shape or a punched metal shape, and carbon cloth, carbon paper or the like as a metal equivalent may be used.

The thickness of the active material layers of the positive electrode and the negative electrode is preferably 30 to 300 μm, more preferably 70 to 130 μm.
Is. Examples of the positive electrode active material include alkali metals or alkaline earth metals such as Li, Na and Ca, Co, Ni and
Complex oxides with transition metals such as Mn and Fe, or
A composite oxide of the above-mentioned alkali metal or alkaline earth metal, transition metal and non-transition metal can be used. As the negative electrode active material, carbon particles such as coke, graphite and amorphous carbon are used, and the shape thereof may be any of crushed shape, scale shape and spherical shape.

The non-aqueous electrolyte is not particularly limited. For example, an electrolyte such as LiClO ₄ , LiBF ₄ , LiAsF ₆ , CF ₃ SO ₃ Li is dissolved in an organic solvent of ethers, ketones, carbonates to form an organic solvent. It can be used as an electrolyte. Moreover, you may use a solid electrolyte. The separator has an ionic conduction function without an electronic conduction function, high resistance to organic solvents, a porous membrane having a fine pore size is used, for example, polyethylene, a microporous membrane made of a polyolefin resin such as polypropylene, Alternatively, a woven porous polyolefin fiber or a non-woven fabric thereof may be used.

As the insulating film, the same one as the separator having no electron conducting function and having ionic conducting function may be used, but it is preferable to use one having neither electron conducting function nor ionic conducting function. That is, an insulating film having neither an electron conducting function nor an ionic conducting function has an extremely thin thickness because it is inexpensive and has high strength as compared with an insulating film having no electron conducting function but an ionic conducting function. However, the required strength can be maintained. Specifically, it is more preferable to use one having neither an ionic conduction function nor an electron conduction function and high resistance to an organic solvent, for example, a polyolefin-based synthetic resin film such as polyethylene, polypropylene, or an ethylene / propylene copolymer. .

When the thickness of the insulating film is smaller than that of the separator, the unit battery can be laminated as an electrode plate laminate for a battery can having the same size as compared with the case where the insulating film has the same thickness as the separator. The total length of the layers can be increased. Therefore, it is preferable to use an insulating film having a thickness smaller than that of the separator. Further, it is preferable that the melting point of the insulating film is lower than the melting point of the separator. This is because when the battery is abnormally heated from the outside, the insulating film melts before the separator, so that a short circuit between the positive and negative electrode current collector foils facing each other through the insulating film causes This is because it occurs before a short circuit occurs between the active materials of the positive electrode and the negative electrode that face each other through.

In particular, the melting point of the insulating film is preferably lower than that of the separator by about 5 to 150 ° C. If the melting point difference is less than 5 ° C., the separator may be melted earlier due to the temperature distribution normally existing in the battery can.
If the temperature is higher than 150 ° C, the insulating film may melt within the temperature range (-20 to 100 ° C) in the battery under normal use.

The battery of the present invention may have a center pin at the winding center of the electrode plate laminate when the electrode plate laminate is a wound type. As the center pin, it is preferable to use a cylindrical body having a cutout portion on the peripheral surface thereof, one having a recessed portion continuous in the circumferential direction on the peripheral surface of the bar material, or a coil spring. The following effects can be obtained by using such a center pin.

That is, in the battery of the present invention, when the electrode plate laminate is crushed in the laminating direction (the direction intersecting the axis), a large stress is applied to the inner peripheral side of the electrode plate laminate, the separator is broken, and the positive plate. And the negative electrode plate come into contact with each other to cause a short circuit, and at that time, the center pin is also crushed and the edge of the cutout portion of the cylinder body is opened outward, or the electrode plate laminated body is formed in the recess of the rod or the gap of the wire of the coil spring. The inner peripheral portion of the electrode bites into and the electrode plate laminate is broken from the inner peripheral side. This allows
Since the short circuit is promoted to occur in a wide range, the current flowing per unit volume of the positive electrode active material is reduced, and the temperature rise of the positive electrode active material is suppressed.

Here, the tubular body is a tubular body which is hollow and is open at both ends in the axial direction, and the cross-sectional outer shape perpendicular to the axial direction is not limited to a circle. The thickness of the cylindrical body is not particularly limited, but in consideration of the area of the cutout portion, the thickness should be such that it can maintain a predetermined strength in normal times, and can be crushed together when a predetermined crushing force is applied in the stacking direction. . Further, the notch means a through hole penetrating from the outer peripheral surface to the inner peripheral surface of the tubular body, and even if it extends parallel to the axial direction of the tubular body, it does not extend in the direction intersecting the axial direction. It may extend, may extend from one end to the other end in the axial direction of the tubular body, may extend only to one end, or may not reach both ends.

When the cutouts extend parallel to the axial direction of the cylindrical body, it is preferable that there are at least two cutouts in the circumferential direction. In particular, if there are three or more notches extending parallel to the axial direction of the tubular body in the circumferential direction, the edges of any notches always open outward regardless of which stacking direction is the crushing direction.
The above-mentioned action is surely obtained. Further, in the case where there are two cutouts, the edges of any cutouts always open outward regardless of the stacking direction in the crushing direction by not arranging them facing each other around the axis of the tubular body. The action is surely obtained.

When the cutout portion extends in a direction intersecting the axial direction of the cylindrical body, the extending direction may be orthogonal to the axial direction or may intersect diagonally. Good. As an example of such a cutout, when the tubular body is a cylinder, one formed along the arc of the cross-sectional circle,
And those formed in a spiral shape on the circumferential surface. In this case, the edge of the notch always opens outward regardless of the crushing direction intersecting the axis, so that the above-mentioned action is surely obtained.

Further, it is preferable that the edge surface of the cut portion is formed in a wavy shape. The wavy shape means an unevenness having an amplitude with respect to the reference line, and the shape may be any of a triangular wave, a rectangular wave, a sine wave, and the like. In this case, since the edge of the crushed and open outward portion becomes a wavy projection, the electrode plate laminate is easily broken and the broken portions are easily dispersed.

As an example of the case where the center pin is formed by forming a continuous recess in the circumferential surface of the bar, a recess having a predetermined width is formed on the peripheral surface of the bar like a screw shaft. There are those in which a plurality of peripheral grooves are formed in the length direction along the cross-section circle of the bar, instead of in a spiral shape. The rod in this case may be solid or hollow. However, if the rod is hollow, the gas in the battery can is guided from the hollow portion toward the safety valve when the internal pressure rises. It is preferable because it is avoided. In the case where the rod is hollow, the recess is limited to one formed so as not to penetrate the inner peripheral surface from the outer peripheral surface of the rod toward the inner peripheral surface.
Further, the deeper the recess is, the higher the above-mentioned bite degree is. Therefore, it is preferable that the recess is deep.

When the center pin is a coil spring, it is preferable that the pitch is larger than the diameter of the wire rod and there is a gap between the adjacent wire rods when there is no load. The gap between adjacent wire rods of the coil spring is preferably 2-3 times the wire rod diameter. The cross-sectional shape of the wire is not particularly limited, and may be a circle or a polygon such as a rhombus. When a saw tooth-shaped recess is formed on the outer peripheral surface like a spring in which the wire rod has a rhombic cross-section, even if the coil spring has no gap between adjacent wire rods when there is no load, it is This is preferable because the inner peripheral portion of the electrode plate laminate is easily bited into this recess.

The material of the center pin is not particularly limited, but stainless steel, which is a metal having both corrosion resistance and strength, is preferable.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a cylindrical non-aqueous battery having a wound electrode plate laminate, which corresponds to the first embodiment of the present invention. This battery is a lithium ion secondary battery in which an electrode plate laminate 1 whose winding method is a winding method is housed in a cylindrical battery can 2. Further, a thin cylindrical center pin 3 is inserted in the winding center of the electrode plate laminate 1. The center pin 3 functions as a flow path that guides the gas inside the battery can 2 toward the safety valve when the internal pressure inside the battery can 2 rises, and is made of stainless steel or the like. Reference numeral 15 is a tab on the positive electrode side, and reference numeral 16 is a tab on the negative electrode side.

The electrode plate laminate 1 comprises a positive electrode plate 11 in which a material containing LiCoO ₂ is applied as a positive electrode active material 11b on only one surface of a current collector foil 11a made of aluminum, and a current collector foil 12a made of copper. A negative electrode plate 12 in which a material containing carbon particles is applied as a negative electrode active material 12b on only one surface of
And a separator 13 composed of a polyethylene microporous film disposed between the positive electrode active material 11b and the negative electrode active material 12b.
And an insulating film 14 made of the same film as the separator 13 arranged between the positive electrode side current collector foil 11a and the negative electrode side current collector foil 12a.

This electrode plate laminate 1 comprises a positive electrode side current collector foil 1
1a, the positive electrode active material 11b, the separator 13, the negative electrode active material 12b, the negative electrode side current collector foil 12a, and the insulating film 14 are laminated in this order with the insulating film 14 inside (that is, the positive electrode side current collector foil 11a outside. Then, it is produced by spirally winding with a winding machine and further winding the insulating film 14 on the outermost periphery. Thereby, the layer structure of the electrode assembly 1 is such that the insulating film 14, the positive electrode side current collector foil 11a, the positive electrode active material 11b, the separator 13, the negative electrode active material 12b, and the negative electrode side are directed inward from the battery can 2 side. The current collector foil 12a, the insulating film 14, and the positive electrode side current collector foil 11a are in this order.

Further, in this electrode plate laminate 1, a unit battery formed of a positive electrode 11 and a negative electrode 12 in which a positive electrode active material 11b and a negative electrode active material 12b are arranged to face each other, and a separator 13 arranged therebetween. Although the cell action occurs in the layer 4, the cell action does not occur between the unit cell layers 4 with the insulating film 14 interposed (that is, between the positive and negative current collector foils 11a and 12a).

Therefore, as shown in FIG. 2, when the battery is crushed in the stacking direction, the innermost separator 13 and the insulating film 1 which are adjacent to the center pin 3 are generally provided.
Since the stress applied to No. 4 is the largest, the separator 13 and the insulating film 14 are sequentially broken from here in the outer peripheral direction, and for example, a short circuit occurs between the positive electrode active material 11b and the negative electrode active material 12b in B and C of FIG. At about the same time, a short circuit occurs between the positive and negative current collector foils 11a and 12a in A and D. Thus, the current collector foil 11a for most current in the short circuit portion, because it is securely disarm flows to 12a, the current flowing in the positive electrode active material 11b consisting of LiCoO ₂ becomes smaller, raising the temperature of LiCoO ₂ is It can be suppressed.

Therefore, even if the charging state is short-circuited, L
Generation of oxygen accompanying temperature rise of iCoO ₂ and reaction of aluminum (positive electrode side current collector foil) and organic solvent (electrolyte solvent) due to this oxygen are suppressed, so that large energy is prevented from being generated inside the battery, The safety of the battery is ensured. Further, as shown in FIG. 3, when the conductor 5 made of a sharp nail or the like penetrates the battery can 2 and enters the inside of the battery, the conductor 5 that becomes the negative electrode at the time of penetrating the battery can 2. The tip has an insulating film 14, a collector foil 11a on the positive electrode side, a positive electrode active material 11b, a separator 13, a negative electrode active material 12b,
The current collector foil 12a on the negative electrode side, the insulating film 14 ... Thus, a short circuit occurs between the positive electrode active material 11b and the negative electrode active material 12b via the conductor 5, but as described above, at the same time as this, the positive and negative current collectors 11 are formed.
Since a short circuit occurs between a and 12a, most of the current flows through the current collectors 11a and 12a even in the short-circuited portion, and the internal discharge is safely performed. Thereby, similarly to the above, even if a short circuit occurs in the charged state, generation of a large amount of energy inside the battery is suppressed, and the safety of the battery is ensured.

When a conductor 5 such as a nail is stabbed from the battery can 2 to a position just before the center pin 3, the conductor 5 is always collected on the positive electrode side before coming into contact with the positive electrode active material 11b. Since it contacts the current collector 11a, most of the current flows to the current collector 11a on the positive electrode side even in the short-circuited portion, and the positive electrode active material 11
It hardly flows to b. Therefore, this battery is particularly excellent in safety when a sharp conductor 5 such as a nail is stabbed in the stacking direction a little.

In the first embodiment, as the insulating film 14 arranged between the unit battery layers 4 (that is, between the positive electrode side current collector foil 11a and the negative electrode side current collector foil 12a), Since the same film as that of the separator 13 is used, the battery action is not generated between the unit battery layers 4, so that the safety of the battery is secured, but the decrease of the electric capacity is unavoidable. That is, in comparison with the conventional structure, when the positive and negative electrode plates having the above structure are wound by the same length, the capacity is halved, and the positive and negative electrode plates are wound longer by the amount that the active material is on only one side of the positive and negative electrodes. Even if it is not the same capacity.

On the other hand, in the battery according to the second embodiment of the present invention shown in FIG. 4, since the insulating film 14 having a smaller film thickness than the separator 13 is used, the battery can 2 having the same size is used. Unit battery layer 4 that can be stacked as the electrode plate stack 1
The length of can be increased. As a result, the electric capacity can be increased while ensuring the safety of the battery as described above. For example, the thickness of the separator used in a normal battery is 25 to 35 μm, but by using a 12 μm insulating film (for example, a polypropylene resin film) as the insulating film 14 instead of the 35 μm separator, the battery can 2 If the diameter is 18 mm and the height is 65 mm, the initial capacity increases by about 8-10%.

Further, in the batteries of the first and second embodiments, since the battery can 2 and the positive electrode plate 12 face each other with the insulating film 14 interposed therebetween, if the insulating film 14 has an ion conducting function,
Charge and discharge may occur between the positive electrode plate 12 and the battery can 2 that is the negative electrode, metal lithium may be deposited on the battery can 2 during charging, and the battery can material may melt during overdischarging. Therefore, as the insulating film 14, for example, a polypropylene resin film having no ion conducting function is used to prevent the deposition of metallic lithium in the battery can 2 during charging and the elution of the battery can material during overdischarging. can do.

Furthermore, the material of the insulating film 14 is changed to the separator 1
If the melting point is lower than 3, the insulating film 14 is melted before the separator 13 when the battery is abnormally heated from the outside, and the positive and negative current collector foils facing each other through the insulating film 14 are provided. The short circuit between 11a and 12a occurs before the short circuit between the positive and negative active materials 11b and 12b facing each other through the separator 13. Thereby, the short-circuit current is reduced to the collector foil 1.
Since it is possible to prevent the positive electrode active material 11b from flowing only in the insulating film 1a and 12a, the insulating film
When the melting point of No. 4 is lower than the melting point of the separator 13, the safety is particularly excellent when the battery is abnormally heated from the outside.

FIG. 5 is a cross-sectional view showing a cylindrical non-aqueous battery having a wound electrode plate laminate, which corresponds to the third embodiment of the present invention. This battery is a lithium-ion secondary battery similar to that of FIG. 1, but can be used for the non-aqueous battery of the present invention, which is different from the center pin 3 of FIG. 1 at the winding center of the electrode plate laminate 1. The second center pin 3a is inserted.

The center pin 3a is made of stainless steel such as SUS304, and has a predetermined width (the cylindrical body has an outer diameter of 4.0 mm, which extends parallel to the axial direction on the peripheral surface of the hollow cylindrical body.
When the thickness is 0.4 mm, for example, the notch 31 of 0.3 mm)
The cutout 31 is formed with the same width from one end to the other end in the length direction of the cylindrical body. In the third embodiment, unlike the first and second embodiments, the notch 31 is formed in the center pin 3a. Therefore, when the battery is crushed in the stacking direction, the imaginary line is shown in FIG. As shown, the center pin 3a is also crushed and the edge of the notch 31 is opened to the outside, and the electrode plate laminate 1 is broken from the inner peripheral side. Therefore, the short circuit between the positive and negative electrode current collector foils 11a and 12a is promoted. Occur over a wide area. Therefore, the battery according to the third embodiment is better than the batteries according to the first and second embodiments.
The safety against crushing in the stacking direction of the batteries is high.

FIG. 7 is a front view showing a third center pin usable in the non-aqueous battery of the present invention. 8 is a cross section taken along the line AA of FIG. 7, and FIG. 9 is a schematic diagram for explaining the action of this center pin. This center pin 3b is made of stainless steel such as SUS304 and, as can be seen from FIGS. 7 and 8, the second center pin 3a.
A predetermined width extending parallel to the axial direction on the peripheral surface of a hollow cylindrical body formed in the same manner as the cutout portion 31 (the cylindrical body has an outer diameter of 4.0 m
m, and a thickness of 0.4 mm, for example, not only the slit 32 of 0.3 mm), but also slits 33a to 33c, 34a that extend in parallel with the axial direction and do not reach the end surface of the cylindrical body.
34c.

The slits 33a to 33c are arranged in series along a straight line parallel to the axial direction at a predetermined interval, and the slits 34a to 34c are predetermined along another straight line parallel to the axial direction. They are arranged in series at intervals. Split 32 and these slits 33a to 33c, 34
a to 34c are arranged to divide the circumference of the center pin 3b into three equal parts.

Therefore, when the battery of FIG. 1 having the center pin 3b is crushed in the stacking direction, the center pin 3b is also crushed and the split port 32 and the slit 33a are crushed.
Since the edges of ~ 33c and 34a to 34c open outward and the electrode plate laminate 1 is broken from the inner peripheral side, the short circuit is promoted and occurs in a wide range. In particular, as shown by the imaginary line in FIG.
When the crushing direction of the battery coincides with one of the cutouts of the center pin 3b (here, the split opening 32), the edge of the split opening 32 enters inside and the electrode plate laminate 1 does not break,
Since the edges of the other slits 33a to 33c and 34a to 34c open outward, the electrode plate laminate 1 is reliably broken regardless of the crushing direction. Further, since the center pin 3b causes a large number of short circuits in the circumferential direction of the electrode plate laminate 1 as compared with the center pin 3a of FIG. 5, the battery having the center pin 3b is the same as the third embodiment. The battery has higher safety against crushing in the stacking direction of the battery.

FIG. 10 is a front view showing a fourth center pin usable in the non-aqueous battery of the present invention. As can be seen from this figure, the center pin 3c corresponds to the one in which the edge surface of the notch 31 of the second center pin 3a is formed in a triangular wave shape except both ends in the length direction. That is, the notch 35 of the center pin 3c is composed of the parallel portions 35a at both ends in the length direction and the corrugated portion 35b at the center. Further, the center pin 3c is formed with a tapered portion 36 having a diameter that decreases toward the end at both ends in the length direction in order to facilitate insertion into the winding center of the electrode plate laminate.

Therefore, when the battery of FIG. 1 having the center pin 3c is crushed in the stacking direction, when the center pin 3c is crushed in accordance with the crushing of the electrode plate laminate in the stacking direction, the center pin 3c is exposed to the outside. Since the edge of the open corrugated portion 35b becomes a saw-toothed protrusion, the electrode plate laminate 1 is more likely to be broken and the fractured portions are more easily dispersed than in the case of the battery having the center pin 3a. Therefore, the battery having the center pin 3c has higher safety against crushing in the stacking direction of the batteries than the battery having the center pin 3a.

FIG. 11 is a front view showing a fifth center pin usable in the non-aqueous battery of the present invention. As can be seen from this figure, the center pin 3d extends on the circumferential surface of the cylindrical body along a direction L ₁ (actually a spiral) diagonally intersecting the axial direction L ₀ thereof, and has a long length. A spiral cutout 37 is formed from one end to the other in the vertical direction, and parallel parts 37a, 37 at both ends in the lengthwise direction parallel to this direction L ₁ are formed.
b and a corrugated portion 37 in which the edge surface of the central portion is formed in a triangular wave shape.
It is composed of c and. Further, as shown in FIG. 12, the spiral of the cutout portion 37 is formed so as to rotate 90 ° between one end 37A in the length direction and the other end 37B. Also,
Also on the center pin 3d, tapered portions 36 having a diameter decreasing toward the end are formed at both ends in the length direction in order to facilitate insertion into the winding center of the electrode plate laminate.

Therefore, when the battery of FIG. 1 having the center pin 3d is crushed in the stacking direction, when the center pin 3d is crushed along with the crushing, the crushing direction intersects any axis. However, since the edge of the cutout 37 is always opened outward, the electrode plate laminate is surely broken. In addition to this, since the edges of the corrugated portion 37c opened to the outside become saw-tooth-shaped projections, the electrode plate laminate is more likely to be broken, and the broken portions are easily dispersed. Therefore, the battery having the center pin 3d has higher safety against crushing in the stacking direction of the batteries than the battery having the center pin 3c.

Further, as compared with the case where a plurality of notches extending in the axial direction are provided in the circumferential direction, it is possible to cope with crushing in any direction intersecting the axis while reducing the opening area of the circumferential surface. Therefore, the strength of the center pin under normal conditions is easily secured even if the thickness is reduced. FIG. 13 is a front view showing a sixth center pin usable in the non-aqueous battery of the present invention.

The center pin 3e has a diameter of about 4 mm.
Is a solid screw shaft having a pitch of 0.7 mm, and has a spiral concave portion 31 on the peripheral surface. The depth of the recess 31 ((“peak diameter” − “valley diameter”) / 2) is about 0.5 mm. Therefore, when the battery of FIG. 1 having the center pin 3e is crushed in the stacking direction, the inner peripheral side portion of the electrode plate stack 1 bites into the recess of the center pin 3d and is extensively broken. Therefore, the battery having the center pin 3e has higher safety against crushing in the stacking direction of the batteries than the batteries of the first and second embodiments.

FIG. 14 is a perspective view showing a seventh center pin usable in the non-aqueous battery of the present invention. The center pin 3f is a stainless steel coil spring made of a wire having a circular cross section, and the wire has a diameter of 0.6 mm and a pitch of 1.6 mm. Therefore, there is a gap of 1.0 mm between the adjacent wire rods when there is no load.

Therefore, when the battery of FIG. 1 having the center pin 3f is crushed in the stacking direction, the inner peripheral side portion of the electrode plate laminate 1 is pressed against the peripheral surface of the coil spring 3f, and the coil spring 3f becomes This part extends in the axial direction while being crushed in the state that it bites into the gap between the adjacent wire rods,
Since the electrode plate laminated body 1 is inclined (the central axis of the coil spring 3f is displaced from the winding center) in the electrode plate laminated body 1, the electrode plate laminated body 1 is widely broken from the inside. Therefore, the battery having the center pin 3f has higher safety against crushing in the stacking direction of the batteries than the batteries of the first and second embodiments.

The electrode plate laminated body 1 in each of the above-described embodiments includes the negative electrode plate 12, the separator 13, and the positive electrode plate 1.
Although the unit battery layer 4 and the insulating film 14 each composed of 1 are wound as described above and wound into a spiral shape by a winding machine, the electrode plate laminate in the battery of the present invention is 1
5, the unit battery layer 4 is laminated in parallel with the insulating film 14 sandwiched therebetween, as shown in FIG. 16, and the unit battery layer 4 and the insulating film 14 are laminated in a predetermined width as shown in FIG. Any structure, such as a zigzag folding type arranged in parallel while being folded back, may be used.

Further, in each of the above-mentioned embodiments, the lithium ion secondary battery has been described, but other non-aqueous secondary batteries or non-aqueous primary batteries are also used when the resistance value of the active material is relatively high. Can ensure the safety of the battery by the same operation as described above.

[0057]

As described above, according to the non-aqueous battery of the present invention, in the overcharged state, the positive electrode active material and the negative electrode are activated by abnormal heating from the outside, crushing in the stacking direction of the battery, nail piercing, or the like. Even if a short circuit occurs with, the rapid temperature rise inside is suppressed, so the safety of the battery is ensured.

In particular, the non-aqueous battery according to the second aspect has high safety in the case where the tip of a nail or the like is slightly pierced in a nail puncture accident. Particularly, in the non-aqueous battery according to claim 3, the required strength can be maintained even if the thickness of the insulating film is extremely thin, so that it becomes possible to use an insulating film having a small film thickness. The electric capacity can be increased while ensuring the safety of.

In particular, in the non-aqueous battery according to claim 4, the length of the unit battery layer that can be stacked as an electrode plate laminate for battery cans of the same size can be increased. It is possible to increase the electric capacity while ensuring the property. Particularly, the non-aqueous battery according to claim 5 has high safety when the battery is abnormally heated from the outside.

Particularly, in the non-aqueous battery according to the sixth aspect, the positive electrode plate and the negative electrode plate are easily manufactured, so that the cost is reduced. In particular, the non-aqueous battery according to claims 10 to 15 has a high safety against crushing in the stacking direction of the batteries by devising the shape of the center pin.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a non-aqueous battery corresponding to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view for explaining the action of the battery of FIG. 1 against crushing.

3 is a schematic cross-sectional view for explaining the action of the conductor of the battery of FIG. 1 with respect to puncturing.

FIG. 4 is a cross-sectional view showing a non-aqueous battery corresponding to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a non-aqueous battery corresponding to a third embodiment of the present invention.

FIG. 6 is a view for explaining the action of the second center pin.

FIG. 7 is a front view showing a third center pin usable in the non-aqueous battery of the present invention.

8 is a cross section taken along the line AA of FIG.

FIG. 9 is a view for explaining the action of the third center pin.

FIG. 10 is a front view showing a fourth center pin usable in the non-aqueous battery of the present invention.

FIG. 11 is a front view showing a fifth center pin usable in the non-aqueous battery of the present invention.

FIG. 12 is a diagram for explaining a cutout portion of the center pin of FIG. 11.

FIG. 13 is a front view showing a sixth center pin usable in the non-aqueous battery of the present invention.

FIG. 14 is a front view showing a seventh center pin usable in the non-aqueous battery of the present invention.

FIG. 15 is a cross-sectional view showing an embodiment in which the electrode plate laminate is a simple laminate type in the non-aqueous battery of the present invention.

FIG. 16 is a cross-sectional view showing an embodiment in which the electrode plate laminate is a zigzag type in the non-aqueous battery of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode plate laminated body 2 Battery can 3 Center pin 3a-3f Center pin 4 Unit battery layer 5 Conductor 11 Positive electrode plate 11a Positive electrode side current collector foil 11b Positive electrode active material 12 Negative electrode plate 12a Negative electrode side current collector foil 12b Negative electrode active material 13 Separator 14 Insulating film 15 Positive electrode side tab 16 Negative electrode side tab 31 Missing part 32 Split opening (missing part) 33a to 33c Slit (missing part) 34a to 34c Slit (missing part) 35 Missing part 35a Parallel part (Notch) 35b Corrugated part (notch) 36 Tapered part 37 Notch 37a Parallel part (notch) 37b Parallel part (notch) 37c Waveform part (notch) 38 Recess

Claims (15)

[Claims] 1. An electrode plate including a positive electrode plate having a positive electrode active material on only one surface of a current collector foil, a negative electrode plate having a negative electrode active material on only one surface of a current collector foil, a separator, and an insulating film. Having a laminate in a battery can, the electrode plate laminate is a unit battery layer in which the surface of the positive electrode plate having the positive electrode active material and the surface of the negative electrode plate having the negative electrode active material face each other with a separator interposed therebetween. Is a non-aqueous battery that is laminated through an insulating film. 2. The non-aqueous battery according to claim 1, wherein a surface of the positive electrode plate having no active material faces a battery can which serves as a negative electrode via an insulating film. 3. The non-aqueous battery according to claim 1, wherein the insulating film has neither electron conduction function nor ion conduction function. 4. The non-aqueous battery according to claim 1, wherein the insulating film is thinner than the separator. 5. The non-aqueous battery according to claim 1, wherein a melting point of the insulating film is lower than a melting point of the separator. 6. The positive electrode plate has a positive electrode active material on one side of the current collector foil, and the negative electrode plate has a negative electrode active material on one side of the current collector foil. The non-aqueous battery according to any one of the above. 7. The electrode plate laminate is one in which unit battery layers are laminated by winding with an insulating film interposed therebetween.
6. The non-aqueous battery according to any one of 6. 8. The non-aqueous battery according to claim 7, wherein the battery structure is a secondary battery. 9. The non-aqueous battery according to claim 7, which has a center pin at the winding center of the electrode plate laminate. 10. The non-aqueous battery according to claim 9, wherein the center pin is a cylindrical body having a cutout portion on its peripheral surface. 11. The non-aqueous battery according to claim 10, wherein the notch portion of the center pin is formed so as to extend parallel to the axial direction of the tubular body, and at least two notch portions are provided in the circumferential direction of the tubular body. 12. The center pin notch is formed so as to extend in a direction intersecting with the axial direction of the cylindrical body.
The non-aqueous battery described. 13. The non-aqueous battery according to claim 10, wherein the edge surface of the cutout portion of the center pin is formed in a wavy shape. 14. The non-aqueous battery according to claim 9, wherein the center pin is formed by forming a recess that is continuous in the circumferential direction on the peripheral surface of the rod material. 15. The non-aqueous battery according to claim 9, wherein the center pin is a coil spring.