JP3178586B2 - Non-aqueous battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 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 an electrode plate laminate spirally wound with a porous resin film having a fine pore diameter as a separator between a positive electrode plate and a negative electrode plate, and has a cylindrical shape serving as a negative electrode. It has inside the stainless steel battery can. As the positive electrode plate, a current collector of an aluminum foil coated with a material containing a lithium composite oxide (LiCoO ₂ or the like) as a positive electrode active material was used. As the negative electrode plate, a material containing carbon as a negative electrode active material was coated. A copper foil current collector is used.

[0003] Currently available electrode plate laminates for lithium ion secondary batteries include one positive electrode plate having an active material coating on both surfaces of an aluminum foil and one sheet having an active material coating on both surfaces of a copper foil. A negative electrode plate and two separators are stacked in the order of a negative electrode plate, a separator, a positive electrode plate, and a separator, and a structure obtained by spirally winding the negative electrode plate outside or an active material on both surfaces of a copper foil Negative plate with separator, separator,
Two positive plates with an active material coating on one side of the aluminum foil (the aluminum foil sides are placed together with the active material coating side facing outward), the separator is stacked in this order, and the negative electrode plate is placed outside. It has a structure obtained by spirally winding.

[0004] Such lithium ion secondary batteries include:
Conventionally, safety valves, thermal fuses, PTC elements, etc. are provided to ensure safety when the temperature inside the battery rises due to a short circuit between the positive and negative electrodes of the battery due to circuit abnormalities or incorrect usage. However, more safety measures are required in preparation for various usage environments and unexpected accidents.

[0005] For example, when a sharp conductor such as a nail is inserted into a battery can in an overcharged state, when the battery is abnormally heated from the outside, or when the battery is crushed in the laminating direction of the electrode plate laminate. Such as often causes a rapid rise in temperature inside.

[0006]

It is clear that a short circuit between the positive electrode and the negative electrode occurs in the battery in such a case, but it is not clear why the temperature will rise sharply inside the battery. The present inventor has found that such a phenomenon occurs due to the following causes, and has completed the present invention.

When a nail or the like, which is a conductor, is inserted into a battery, the tip of the nail penetrates the battery can, which is a negative electrode, and comes into contact with the internal positive electrode plate in a state of becoming a negative electrode. Short circuit occurs. In addition, 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 that have been insulated by the separator come into contact with each other, causing a short circuit. Further, when the battery is crushed in the laminating 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 resistance of the lithium composite oxide (positive electrode active material) among the members constituting the electrode plate laminate is relatively high. Easy to rise. Then, the heat generated by this temperature increase causes the organic solvent inside the battery to easily undergo a decomposition reaction. Also, when such a short circuit occurs in a charged battery, the lithium composite oxide in the charged state is in an unstable state in which lithium has escaped to some extent as an ion. Likely to happen. The oxygen easily reacts with the aluminum foil or the organic solvent on which the lithium composite oxide is deposited.

According to the present invention, even when the battery is abnormally heated from the outside, a sharp conductor such as a nail is pierced into a battery can, and the battery is crushed in the stacking direction of the electrode plate laminate, It is an object of the present invention to provide a non-aqueous battery that makes it difficult to cause a short circuit between a positive electrode active material and a negative electrode, or suppresses a rise in temperature of the positive electrode active material accompanying the short circuit even when it occurs, thereby ensuring safety. Is what you do.

[0010]

In order to solve the above problems, the present invention provides a positive electrode plate having a positive electrode active material only on one side of a current collector foil, and a negative electrode active material only on one side of a current collector foil. A negative electrode plate, a separator, and an insulating film, each having an electrode plate laminate in a battery can, wherein the electrode plate laminate has a surface having a positive electrode active material of a positive electrode plate and a negative electrode active material of a 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 stacked via an insulating film.

As a specific example of the method for producing the electrode plate laminate, a method in which a unit battery layer and an insulating film are overlapped and wound in a spiral shape by a winding machine (winding type), And a method in which a unit battery layer and an insulating film are overlapped with each other and are folded in a predetermined width and arranged in parallel (a zigzag type).

In the structure of the nonaqueous battery according to the present invention, the positive electrode active material surface and the negative electrode active material surface face each other with a separator interposed therebetween, and the positive and negative current collector foil surfaces having no active material have an insulating film interposed therebetween. Are 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 nailing, etc., a short-circuit between the positive and negative current collector foil surfaces that does not necessarily 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, even in the short-circuited portion, current mainly flows through the current collector foil having a low resistance value, and the current flowing through the positive electrode active material decreases. Therefore, an abnormal rise in the temperature of the positive electrode active material during a short circuit can be suppressed.

In the non-aqueous battery of the present invention, the battery can
A material having no conductivity, such as a material serving as a negative electrode, a material serving as a positive electrode, or a resin that is neither of them may be used. When the battery can is made of a non-conductive substance such as a resin, an external electrode can be provided on the battery can. When the battery can is the negative electrode, it is preferable that the surface of the positive electrode plate having no active material faces the battery can via the insulating film. In this case, in the event of a nail penetration 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 of the negative electrode, causing a short circuit. This is because, in such a case, since the tip always contacts the current collector foil before contacting the positive electrode active material, almost no current flows through the positive electrode active material.

In the case of a 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 to produce an electrode plate laminate. Obtained by putting in. In the case of the simple stack type, for example, an electrode plate laminate is manufactured by stacking a plurality of unit battery layers with the positive electrode plate side and the negative electrode plate side facing each other and an insulating film interposed therebetween, The negative electrode plate side is aligned with the center of the stacking direction, an insulating film is arranged between at least both end faces of each unit battery layer and the battery can, and if necessary, the uppermost surface of the electrode plate laminate and the battery can are It can be obtained by arranging an insulating film between the lowermost surface and the battery can. In the zigzag type, the electrode plate laminate is manufactured by folding the unit battery layer so that the positive electrode plate side is disposed on the inner surface parallel to the folded unit surface, of the inner surface of the battery can, and at least the It is obtained by disposing an insulating film between the positive electrode plate disposed 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 provided with the active material on one entire surface or partially on the active material. Are preferred because they are easy to manufacture. It is necessary that no active material is adhered to the other surface and that the current collector surface is entirely exposed. Examples of the current collector foil of the positive electrode include metal foils such as aluminum, titanium, and stainless steel, with aluminum being preferred. The thickness of the current collector foil of the positive electrode is generally 5 to 100 μm, preferably 8 to 50 μm.
m, more preferably 10 to 50 μm.

As the 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 expanded metal or punched metal, and carbon cloth or carbon paper 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.
It is. As the positive electrode active material, an alkali metal or an alkaline earth metal such as Li, Na, and Ca, and Co, Ni,
A composite oxide with a transition metal such as Mn or Fe, or
A composite oxide of the 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 a crushed shape, a scale-like shape, and a 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 such as ethers, ketones and carbonates to form an organic solvent. It can be used as an electrolyte. Further, a solid electrolyte may be used. As the separator, a porous membrane having a fine pore size is used, which has an ion conduction function without an electron conduction function and has a high resistance to organic solvents, for example, a microporous film made of a polyolefin-based resin such as polyethylene and polypropylene, Alternatively, a woven fabric of a polyolefin-based porous fiber or a nonwoven fabric thereof may be used.

As the insulating film, the same one as the separator having no electronic conduction function and having the ion conduction function may be used. However, it is preferable to use an insulating film having neither the electronic conduction function nor the ion conduction function. That is, an insulating film having neither an electronic conduction function nor an ion conduction function has no electron conduction function but is inexpensive and has higher strength than an insulation film having an ion conduction function. The required strength can be maintained. Specifically, it is more preferable to use one having no ion-conducting function nor electron-conducting function and having high resistance to an organic solvent, for example, a polyolefin-based synthetic resin membrane such as polyethylene, polypropylene, and ethylene-propylene copolymer. .

When the thickness of the insulating film is smaller than the thickness of the separator, the unit battery can be laminated as an electrode plate laminate for a battery can of 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 the thickness 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 is melted before the separator, so the short-circuit between the collector foils of the positive electrode and the negative electrode facing each other via the insulating film This occurs before a short circuit occurs between the active materials of the positive electrode and the negative electrode that face each other through the electrode.

In particular, the melting point of the insulating film is preferably lower by about 5 to 150 ° C. than the melting point of the separator. When the difference in the melting point is smaller than 5 ° C., the separator may melt earlier due to the temperature distribution normally present in the battery can,
If the temperature is higher than 150 ° C., the insulating film may be melted in a range of the temperature in the battery in a normal use state (−20 to 100 ° C.).

When the electrode plate laminate is of a wound type, the battery of the present invention may have a center pin at the center of the wound electrode plate laminate. The center pin is preferably a cylindrical body having a notch in the peripheral surface, a rod having a concave portion continuous in the circumferential direction on the peripheral surface of the rod, or a coil spring. The following effects can be obtained by using such a center pin.

That is, when the battery of the present invention is crushed in the laminating direction (the direction intersecting the axis) of the electrode plate laminate, a large stress is applied to the inner peripheral side of the electrode plate laminate to break the separator, and the positive electrode plate is broken. And the negative electrode plate come into contact with each other to cause a short circuit. At this time, the center pin is also crushed and the edge of the cutout of the cylindrical body is opened outward, or the electrode plate laminate is inserted into the concave portion of the rod or the gap between the wires of the coil spring. Of the electrode plate cuts into the electrode plate laminate from the inner peripheral side. This allows
Since the short circuit is promoted and occurs over a wide area, 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 cylindrical body is a hollow tubular body having both ends opened in the axial direction, and the cross-sectional shape perpendicular to the axial direction is not limited to a circle. Although the thickness of the cylindrical body is not particularly limited, it is set to a thickness that can maintain a predetermined strength in a normal state and crush together when a predetermined crushing force is applied in the stacking direction in consideration of the area of the notch. . In addition, the notch means a through hole that penetrates from the outer peripheral surface to the inner peripheral surface of the cylindrical body, and extends in parallel to the axial direction of the cylindrical body, even in a direction intersecting the axial direction. It may extend, may extend from one end in the axial direction of the cylindrical body to the other end, may extend only to one end, or may not extend to both ends.

When the cutout extends 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 cutouts extending in the circumferential direction parallel to the axial direction of the cylindrical body, the edges of any cutouts always open outward even if the crushing direction is any lamination direction,
The above operation can be obtained reliably. In addition, in the case of two notches, the edge of one of the notches always opens outward even if the crushing direction is any lamination direction by not disposing the center of the cylindrical body so as to face the center. The action is reliably obtained.

When the notch extends in a direction intersecting the axial direction of the cylindrical body, the extending direction may be orthogonal to the axial direction or obliquely intersecting. Good. As an example of such a notch, when the cylindrical body is a cylinder, one formed along an arc of a cross-sectional circle thereof,
And those spirally formed on the circumferential surface. In this case, the edge of the notch always opens outward regardless of the direction in which the crushing direction intersects the axis, so that the above-described operation is reliably obtained.

It is preferable that the edge surface of the notch is formed in a wavy shape. The wavy shape means irregularities having an amplitude with respect to a reference line, and may have any shape such as a triangular wave, a rectangular wave, and a sine wave. In this case, the edge of the notched portion that is crushed and opened outward becomes a wavy projection, so that the electrode plate laminate is easily broken and the broken portions are easily dispersed.

An example of a case where the center pin is formed by forming a concave portion continuous in the circumferential direction on the peripheral surface of the bar is a concave portion having a predetermined width on the peripheral surface of the bar, such as a screw shaft. Are formed in a spiral shape, and those in which a number of circumferential grooves are formed in the length direction along the cross-sectional circle of the bar member instead of the 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 toward the safety valve when the internal pressure increases. Preferred for In addition, when the rod is hollow, the recess is limited to a depth formed so as not to penetrate the inner peripheral surface from the outer peripheral surface to the inner peripheral surface side of the rod.
In addition, the deeper the concave portion, the higher the degree of the bite becomes, so that the concave portion is preferably deep.

When the center pin is a coil spring, it is preferable that the pitch is larger than the diameter of the wire and that there is a gap between adjacent wires when no load is applied. Preferably, the gap between adjacent wires of the coil spring is two to three times the wire diameter. The cross-sectional shape of the wire is not particularly limited, and may be a circle or a polygon such as a rhombus. If the cross section of the wire is a diamond-shaped spring with a saw-tooth-shaped recess formed on the outer peripheral surface, even if the coil spring has no gap between adjacent wires when no load is applied, even when the crushing is performed, This is preferable because the inner peripheral portion of the electrode plate laminate easily penetrates into the concave portion.

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

[0031]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a cylindrical nonaqueous battery in which the electrode plate laminate is a wound type, corresponding to the first embodiment of the present invention. This battery is a lithium ion secondary battery in which an electrode plate laminate 1 whose lamination method is a wound type is housed in a cylindrical battery can 2. A thin cylindrical center pin 3 is inserted into the center of the wound electrode plate laminate 1. The center pin 3 serves as a flow path for guiding the gas in the battery can 2 toward the safety valve when the internal pressure in the battery can 2 increases, and is formed 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 includes 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 only on one side of
And a separator 13 made of a microporous polyethylene 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 disposed between the positive electrode side current collector foil 11a and the negative electrode side current collector foil 12a.

The electrode plate laminate 1 is formed of 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 stacked in this order so that the insulating film 14 is on the inside (that is, the positive electrode side current collector foil 11a is on the outside). ), And wound in a spiral by a winding machine, and the insulating film 14 is further wound on the outermost periphery. As a result, the layer structure of the electrode assembly 1 has an insulating film 14, a positive electrode current collector foil 11a, a positive electrode active material 11b, a separator 13, a negative electrode active material 12b, and a negative electrode side. The current collector foil 12a, the insulating film 14, and the positive electrode side current collector foil 11a are arranged in this order.

In the electrode plate laminate 1, a unit battery is formed by the positive electrode 11 and the negative electrode 12 in which the positive electrode active material 11 b and the negative electrode active material 12 b are arranged to face each other, and the separator 13 arranged therebetween. Although a battery action occurs in the layer 4, no battery action occurs between the unit battery layers 4 with the insulating film 14 interposed therebetween (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, generally, the innermost separator 13 and the insulating film 1 adjacent to the center pin 3 are crushed.
4, the separator 13 and the insulating film 14 are sequentially broken in the outer circumferential direction from this point, and for example, a short circuit between the positive electrode active material 11b and the negative electrode active material 12b occurs in B and C in FIG. Almost at 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 Can be suppressed.

Therefore, even if the charging state is short-circuited, L
Since the generation of oxygen due to the temperature rise of iCoO ₂ and the reaction of aluminum (cathode-side current collector foil) and organic solvent (electrolyte solvent) by this oxygen are suppressed, generation of large energy inside the battery is prevented, Battery safety is ensured. As shown in FIG. 3, when the conductor 5 made of a sharp nail or the like breaks through the battery can 2 and enters the inside of the battery, the conductor 5 that has become the negative electrode when penetrating the battery can 2 is formed. The tip is an insulating film 14, a current collector foil 11a on the positive electrode side, a positive electrode active material 11b, a separator 13, a negative electrode active material 12b,
The collector foil 12a on the negative electrode side, the insulating film 14,... As described above, 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, almost simultaneously with this, the positive and negative current collectors 11b
Since a short-circuit occurs between the current collectors a and 12a, most of the current flows to the current collectors 11a and 12a even at the short-circuited portion, and the internal current is safely discharged. As a result, as described above, even if the charging state is short-circuited, generation of large energy inside the battery is suppressed, and the safety of the battery is ensured.

When a conductor 5 such as a nail is inserted from the battery can 2 to a position short of the center pin 3, the conductor 5 must be connected to the positive electrode active material 11b before coming into contact with the positive electrode active material 11b. Most of the current flows to the current collector 11a on the positive electrode side even in the short-circuited portion because the current collector 11a contacts the current collector 11a.
It hardly flows to b. Therefore, this battery is particularly excellent in safety when the sharp conductor 5 such as a nail is slightly inserted in the stacking direction.

In the first embodiment, the insulating film 14 disposed between the unit battery layers 4 (ie, between the positive electrode current collector foil 11a and the negative electrode current collector foil 12a) is Since the same membrane as that of the separator 13 is used, the battery action does not occur between the unit battery layers 4 and the safety of the battery is ensured, but the reduction of the electric capacity is inevitable. That is, as compared with the conventional structure, when the positive and negative electrode plates of the above structure are wound by the same length, the capacity is halved, and the positive and negative electrode plates are rolled as long as the active material has only one surface with the positive and negative electrodes. Even if the capacity is not the same.

On the other hand, in the battery according to the second embodiment of the present invention shown in FIG. 4, a thinner film than the separator 13 is used as the insulating film 14, so that the same size battery for the battery can 2 is used. Unit battery layer 4 that can be laminated as electrode plate laminate 1
Can be lengthened. As a result, the electric capacity can be increased while ensuring the safety of the battery as described above. For example, the thickness of a 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 to 10%.

In the batteries of the first and second embodiments, the battery can 2 and the positive electrode plate 12 face each other with the insulating film 14 interposed therebetween.
Charging / discharging occurs between the positive electrode plate 12 and the battery can 2 as the negative electrode, metal lithium is deposited on the battery can 2 during charging, and the battery can material may be melted during overdischarge. Therefore, the use of a material having no ion-conducting function, such as a polypropylene resin film, as the insulating film 14 prevents deposition of metallic lithium on the battery can 2 during charging and elution of the battery can material during overdischarge. can do.

Further, the material of the insulating film 14 is
Assuming that the melting point is lower than 3, when the battery is abnormally heated from the outside, the insulating film 14 is melted before the separator 13 and the positive and negative current collector foils facing each other with the insulating film 14 interposed therebetween. 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 with the separator 13 interposed therebetween. As a result, the short-circuit current is reduced
1A and 12A, but not to the positive electrode active material 11b.
When the melting point of the battery 4 is lower than the melting point of the separator 13, the safety when the battery is abnormally heated from the outside becomes particularly excellent.

FIG. 5 is a cross-sectional view showing a cylindrical non-aqueous battery in which the electrode plate laminate is a wound type, corresponding to the third embodiment of the present invention. This battery is a lithium ion secondary battery similar to that of FIG. 1, but is different from the center pin 3 of FIG. 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 outer diameter of the cylindrical body is 4.0 mm, extending parallel to the axial direction) on the peripheral surface of the hollow cylindrical body.
Notch 31 having a thickness of 0.4 mm, for example, 0.3 mm)
The notch 31 has 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 examples, the notch 31 is formed in the center pin 3a. Therefore, when the battery is crushed in the stacking direction, the dashed line in FIG. As shown in the figure, the center pin 3a is also crushed and the edge of the notch 31 is opened outward, and the electrode plate laminate 1 is broken from the inner peripheral side, so that a short circuit between the positive and negative electrode current collector foils 11a and 12a is promoted. Occur widely. Therefore, the battery of the third embodiment is more than the batteries of the first and second embodiments.
The safety against crushing in the battery stacking direction is high.

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

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

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 slit 32 and the slit 33a are crushed.
33c and 34a to 34c are opened outward, and the electrode plate laminate 1 is broken from the inner peripheral side, so that 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 slit 32), the edge of the slit 32 enters inside and the electrode plate laminate 1 is not broken,
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. The center pin 3b has a larger number of short circuits in the circumferential direction of the electrode plate laminate 1 than the center pin 3a of FIG. The battery has higher safety against crushing in the battery stacking direction than the battery.

FIG. 10 is a front view showing a fourth center pin usable for the non-aqueous battery of the present invention. As can be seen from this figure, the center pin 3c is equivalent to the one in which the edge surface of the notch 31 of the second center pin 3a is formed in a triangular waveform except for both ends in the length direction. That is, the notch 35 of the center pin 3c is constituted by the parallel portion 35a at both ends in the length direction and the corrugated portion 35b at the center. In addition, the center pin 3c is formed with a tapered portion 36 whose diameter decreases toward the end at both ends in the longitudinal direction so as to be easily inserted into the center of the winding 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 with the crushing of the electrode plate laminate in the stacking direction, the battery becomes outward. Since the edge of the opened corrugated portion 35b becomes a saw-toothed protrusion, the electrode plate laminate 1 is more easily broken and the broken 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 battery stacking direction than the battery having the center pin 3a.

FIG. 11 is a front view showing a fifth center pin usable for the non-aqueous battery of the present invention. As can be seen from this figure, the center pin 3d is the peripheral surface of the cylindrical body, extend along the direction L ₁ intersecting obliquely with the axial direction L ₀ (actually has a spiral), the length It is direction end and the helical cut-out portion 37 leading to the other end is formed from the parallel portion 37a of the both longitudinal ends parallel to the direction L _1, 37
b and a corrugated portion 37 whose central edge is formed in a triangular waveform.
c. As shown in FIG. 12, the spiral of the notch 37 is formed so as to rotate 90 ° between one end 37A and the other end 37B in the longitudinal direction. Also,
This center pin 3d is also formed with a tapered portion 36 whose diameter decreases toward the end at both ends in the longitudinal direction so as to be easily inserted into the center of the wound electrode plate laminate.

Therefore, when the battery of FIG. 1 having the center pin 3d is crushed in the stacking direction, if the center pin 3d is crushed by the crushing, the crushing direction is any direction that intersects the axis. Even so, the edge of the notch 37 always opens outward, so that the electrode plate laminate is reliably broken. In addition, since the edge of the corrugated portion 37c opened to the outside becomes a saw-toothed protrusion, the electrode plate laminate is more easily broken and the broken portions are more easily dispersed. Therefore, the battery having the center pin 3d has higher safety against crushing in the battery stacking direction than the battery having the center pin 3c.

Further, compared to 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, even when the thickness is reduced, the strength of the center pin in a normal state is easily secured. FIG. 13 is a front view showing a sixth center pin usable for 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 ((“peak diameter” − “valley diameter”) / 2) of the concave portion 31 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 laminate 1 cuts into the recess of the center pin 3d and is widely broken. Therefore, the battery having the center pin 3e has higher safety against crushing in the battery stacking direction than the batteries of the first and second embodiments.

FIG. 14 is a perspective view showing a seventh center pin usable for the non-aqueous battery of the present invention. The center pin 3f is a coil spring made of stainless steel and made of a wire having a circular cross section. 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 adjacent wires when no load is applied.

Therefore, when the battery of FIG. 1 having the center pin 3f is crushed in the stacking direction, the inner peripheral portion of the electrode plate laminate 1 is pressed against the peripheral surface of the coil spring 3f, and the coil spring 3f This part extends in the axial direction while being crushed in a state of biting into the gap between adjacent wires,
The electrode plate laminate 1 is tilted in the electrode plate laminate 1 (the center axis of the coil spring 3f is shifted from the center of the winding), so that the electrode plate laminate 1 is widely broken from the inside. Therefore, the battery having the center pin 3f has higher safety against crushing in the battery stacking direction than the batteries of the first and second embodiments.

The electrode plate laminate 1 in each of the above embodiments includes a negative electrode plate 12, a separator 13, and a positive electrode plate 1.
1 is a wound type in which the unit battery layer 4 made of No. 1 and the insulating film 14 are overlapped and wound in a spiral or the like by a winding machine as described above. The electrode plate laminate in the battery of the present invention is shown in FIG. 1
As shown in FIG. 5, a simple stacked type in which the unit battery layers 4 are overlapped in parallel with the insulating film 14 interposed therebetween, and as shown in FIG. Any structure, such as a zigzag type that is arranged in parallel while being folded back, may be used.

In each of the above embodiments, a lithium ion secondary battery has been described. However, other non-aqueous secondary batteries or non-aqueous primary batteries may be used when the active material has a relatively high resistance value. Can secure 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 overheated by external abnormal heating, crushing of the battery in the stacking direction, or nail penetration. Even if a short circuit occurs with the battery, abrupt temperature rise inside is suppressed, so that the safety of the battery is ensured.

In particular, the non-aqueous battery according to the second aspect has a high safety in a case where the tip of a nail or the like is slightly inserted in a nail sticking accident. In particular, the non-aqueous battery according to claim 3 can maintain the required strength even when the thickness of the insulating film is extremely thin, so that a thin insulating film can be used. The electric capacity can be increased while ensuring the safety of the device.

In particular, in the non-aqueous battery according to the fourth aspect, it is possible to increase the length of the unit battery layer that can be laminated as an electrode plate laminate for a battery can of the same size. The electric capacity can be increased while ensuring the performance. In particular, the non-aqueous battery according to claim 5 has high safety when the battery is abnormally heated from the outside.

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

[Brief description of the 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 on crushing.

FIG. 3 is a schematic cross-sectional view for explaining an effect of the battery of FIG. 1 on insertion of a conductor.

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

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

FIG. 6 is a diagram for explaining the operation of a second center pin.

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

FIG. 8 is a sectional view taken along line AA of FIG. 7;

FIG. 9 is a diagram for explaining the function of a third center pin.

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

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

FIG. 12 is a diagram for explaining a missing portion of the center pin in FIG. 11;

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

FIG. 14 is a front view showing a seventh center pin usable for 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 nonaqueous battery of the present invention.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode board laminated body 2 Battery can 3 Center pin 3a-3f Center pin 4 Unit battery layer 5 Conductor 11 Positive electrode plate 11a Current collector foil on the positive electrode side 11b Positive active material 12 Negative electrode plate 12a Current collector foil on the negative electrode side 12b Negative electrode active material 13 Separator 14 Insulating film 15 Positive side tab 16 Negative side tab 31 Notch 32 Splitter (cutout) 33a-33c Slit (cutout) 34a-34c Slit (cutout) 35 Notch 35a Parallel portion (Notched portion) 35b Corrugated portion (cutout portion) 36 Tapered portion 37 Notched portion 37a Parallel portion (cutout portion) 37b Parallel portion (cutout portion) 37c Waveform portion (cutout portion) 38 Concave portion

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01M 10/00-10/40 H01M 4/64-4/84 H01M 6/00-6/22 H01M 4 / 02-4/04

Claims (15)

(57) [Claims] An electrode plate comprising: a positive electrode plate having a positive electrode active material on only one side of a current collector foil; a negative electrode plate having a negative electrode active material on only one side of a current collector foil; a separator; and an insulating film. The electrode plate laminate includes unit battery layers in which a surface having a positive electrode active material of a positive electrode plate and a surface having a negative electrode active material of a negative electrode plate are arranged to face each other with a separator interposed therebetween. Are laminated with an insulating film interposed therebetween. 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 serving as a negative electrode via an insulating film. 3. The non-aqueous battery according to claim 1, wherein the insulating film has neither an electron conduction function nor an ion conduction function. 4. The non-aqueous battery according to claim 1, wherein the thickness of the insulating film is smaller than the thickness of 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 method according to claim 1, wherein the positive electrode plate has a positive electrode active material on one entire surface of the current collector foil, and the negative electrode plate has a negative electrode active material on one entire surface of the current collector foil. The non-aqueous battery according to any one of the above. 7. The electrode plate laminate according to claim 1, wherein the unit battery layers are laminated by winding via an insulating film.
7. The non-aqueous battery according to any one of 6. 8. The non-aqueous battery according to claim 7, wherein the battery is a secondary battery. 9. The non-aqueous battery according to claim 7, wherein the electrode plate laminate has a center pin at the center of winding. 10. The non-aqueous battery according to claim 9, wherein the center pin is a cylindrical body having a cutout on a peripheral surface. 11. The non-aqueous battery according to claim 10, wherein the notch of the center pin is formed so as to extend in parallel with the axial direction of the cylindrical body, and at least two center pins are provided in the circumferential direction of the cylindrical body. 12. The center pin notch is formed so as to extend in a direction intersecting the axial direction of the cylindrical body.
The non-aqueous battery as described. 13. The non-aqueous battery according to claim 10, wherein an 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 concave portion that is continuous in the circumferential direction on the peripheral surface of the bar. 15. The non-aqueous battery according to claim 9, wherein the center pin is a coil spring.