JP2002015764A - Battery, battery electrode forming method and electrode forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode which has a shape of a groove that does not give a damage to the electrode, and a forming method of the electrode and a forming device of the battery and the electrode. SOLUTION: The battery comprises a generating element in which a positive electrode and a negative electrode are arranged interposing an electrolyte supporting layer, and has an electrode active material layer 2 on both faces of the current collector 3. In at least one of the electrodes 1, the sectional shape has a bottom face section 5 and a side face section 6, in which the angle formed by the bottom face section 5 and the side face section 6 is made an acute angle and forms a groove 4 of which one end at least extends to the edge of the electrode 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery comprising a power generating element in which positive and negative electrodes are alternately arranged close to each other via an electrolyte holding layer for holding an electrolyte such as a separator.
The present invention also relates to an electrode forming method and an electrode forming apparatus for the battery.

[0002]

2. Description of the Related Art In general, a chemical battery such as a primary battery or a secondary battery includes a power generating element in which positive and negative electrodes are arranged close to each other via a separator or the like which holds an electrolyte and plays a role of an insulating film. For example, a wound-type battery forms a cylindrical power generating element by spirally winding a positive electrode and a negative electrode one by one with a separator interposed therebetween. Further, in the stacked battery, a power generating element is formed by alternately stacking a plurality of positive and negative electrodes via a separator. The formed power generating element is housed in a case and pressed from the outside to maintain the adhesion between each of the positive and negative electrodes and the separator, thereby preventing displacement and resistance rise. There is also a battery in which the positive and negative electrodes of the power generating element and the separator are joined with an electrolyte-retaining resin or the like so as to maintain the adhesion without being pressed from the outside.

However, if a power generating element formed by external compression or internal bonding is brought into close contact as in the prior art, there is almost no gap between the electrode and the separator. In addition, most of the permeation of the electrolyte into the inside of the power generation element is caused by permeation from the side surface of the electrode and permeation from the separator. Therefore, it took a considerably long time for the electrolyte to permeate the entire power generating element.

As a method for solving this problem, International Publication No. WO9,848,466 discloses providing a groove on the electrode surface. According to this, it is disclosed that by forming a groove reaching the end of the electrode, it becomes possible to increase the infiltration rate of the electrolyte solution, the degassing rate generated inside, and the evaporation rate of the solvent for bonding. I have.

[0005]

When a groove is formed in an electrode, for example, in a groove having a cross-sectional shape such as a wedge shape or a round shape, when a groove is formed by compression,
There was a possibility that the groove portion was damaged, or if the damage was severe, it was cut.

Further, when the angle formed between the groove bottom surface and the side surface in the groove cross-sectional shape having the groove bottom surface and the side surface becomes a right angle or an acute angle, when the groove is formed by being compressed by the molding projection, the periphery of the groove is formed. The portion is easily damaged, and the fragments due to the damage adhere to the mold and the electrode after the groove processing to generate a defective product, which causes a reduction in yield.

In an electrode having an active material layer formed on both surfaces of a current collector plate, deformation is likely to occur when grooves are formed on both surfaces of the electrode, and the electrode is passed through a thickness adjusting rolling press after the grooves are formed. Later, there is a possibility that a problem such as the deformation of the groove remains or the depth of the groove becomes shallow.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the formation of grooves for increasing the rate of injecting the electrolyte, the rate of degassing, and the rate of drying the solvent can be performed more reliably. It is another object of the present invention to improve the yield by making it possible to do so without damaging the electrodes.

[0009]

A first battery according to the present invention comprises a power generating element in which positive and negative electrodes having electrode active material layers on both surfaces of a current collector are arranged via an electrolyte holding layer. In the battery, at least one of the two active electrode layers of the positive electrode and the negative electrode, at least one end is formed with a plurality of grooves reaching the end of the electrode, the cross-sectional shape of the groove has a side portion and a bottom portion, The angle between the bottom surface and the side surface is an obtuse angle.

A second battery according to the present invention is a battery according to the first battery, wherein the bottom surfaces of the grooves of both electrode active material layers are formed so as to overlap with each other.

[0011] A third battery according to the present invention is the first battery, wherein the bottom surfaces of the grooves of both electrode active material layers are formed at substantially opposing positions, and the cross section of the groove of both electrode active material layers is provided. The width of the bottom portion in the shape is different.

A fourth battery according to the present invention is the battery according to the first battery, wherein the thickness of the electrode in which the groove is formed is t ₁ , the thickness of the current collector plate of the electrode is t ₂ , T ₃ ,
When the porosity of the active material layer of the electrode is P, the lateral elongation by compression of the active material layer is r ₁ , and the lateral elongation by compression of the current collector plate is r ₂ , The shape of the groove satisfies the following expression (1). t ₃ = (t ₁ −t ₂ ) × (1−P) × (1−r ₁ ) + t ₂ × (1−r ₂ ) Equation (1)

A fifth battery according to the present invention is the battery according to the first battery, wherein the angle between the bottom surface and the side surface is greater than 90 degrees and 170 degrees or less.

According to a sixth battery of the present invention, in the first battery, the width of the bottom surface in the cross-sectional shape of the groove is 0.1%.
mm or more and 1.0 mm or less.

A seventh battery according to the present invention is the above-described second battery, wherein the ratio of the width of the bottom portion in the cross-sectional shape of the overlapping groove is at least 1 and at most 3 times.

An eighth battery according to the present invention is the above-mentioned first battery, wherein the distance between adjacent grooves is 20 mm or less.

A ninth battery according to the present invention is the battery according to the first battery, wherein the ratio of the groove area to the surface area of the electrode active material layer is 20% or less.

A tenth battery according to the present invention is the above first battery, wherein at least one of the positive electrode and the electrolyte holding layer and the negative electrode and the electrolyte holding layer are fixed by an adhesive layer. is there.

The first electrode forming method according to the present invention is directed to a method of forming a battery having a power generating element in which positive and negative electrodes having electrode active material layers on both surfaces of a current collector are arranged via an electrolyte holding layer. In the electrode forming method, both electrode active material layers of the electrode,
A groove is formed by pressing a mold having a projection formed of a flat portion on an upper portion and a side portion formed at an obtuse angle with the flat portion from both sides of the electrode active material layer. .

According to a second electrode forming method according to the present invention, in the first electrode forming method, the thickness of the electrode forming the groove is t ₁ , the thickness of the current collector plate of the electrode is t ₂ , The thickness of the electrode in the groove is t ₃ , the porosity of the active material layer of the electrode is P,
When the elongation rate in the horizontal direction due to the compression of the electrode active material layer is r ₁ and the elongation rate in the horizontal direction due to the compression of the current collector plate is r ₂ , the shape of the groove is expressed by the following formula (1). The height of the protrusion is formed so as to satisfy the above. t ₃ = (t ₁ −t ₂ ) × (1−P) × (1−r ₁ ) + t ₂ × (1−r ₂ ) Equation (1)

According to a third electrode forming method of the present invention, in the first electrode forming method, the ratio of the area of the flat portion of the projection to the surface area of the electrode active material layer is set to 20% or less.

A first electrode forming apparatus according to the present invention is directed to a battery provided with a power generating element in which positive and negative electrodes having electrode active material layers on both surfaces of a current collector are arranged via an electrolyte holding layer. In the electrode forming apparatus, two dies are disposed with the electrode interposed therebetween, and two molds each having a projection formed by a flat portion and a side portion formed at an obtuse angle with the flat portion are formed on the upper portion, and the metal mold. The mold is provided with a mold driving unit that presses the mold from both sides of the electrode to compress the electrode active material layer.

In a second electrode forming apparatus according to the present invention, in the first electrode forming apparatus, the flat portions of the projections of the two dies are arranged so as to overlap with each other.

According to a third electrode forming apparatus of the present invention, in the above second electrode forming apparatus, the ratio of the width of the flat portion in the cross-sectional shape of the overlapping projection is 1 to 3 times. .

In a fourth electrode forming apparatus according to the present invention, in the first electrode forming apparatus, the flat portions of the projections of the two dies are arranged so as to substantially face each other, and They differ in width.

According to a fifth electrode forming apparatus of the present invention, in the first electrode forming apparatus, the angle formed between the flat portion and the side portion of the projection is greater than 90 degrees and 170 degrees or less.

According to a sixth electrode forming apparatus of the present invention, in the first electrode forming apparatus, the width of the flat portion in the cross-sectional shape of the projection is 0.1 mm or more and 1.0 mm or less. .

According to a seventh electrode forming apparatus of the present invention, in the first electrode forming apparatus, an interval between adjacent projections is 20 mm or less.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described focusing on lithium ion batteries which are currently being actively developed mainly for portable devices, but the invention is not limited to these. Absent. In addition, an object of the invention may be either a positive electrode or a negative electrode, and the present embodiment can be applied to the other electrode in the example using either the positive electrode or the negative electrode.

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, and is a cross-sectional view showing a shape of a grooved electrode. In the figure, 1 is a positive electrode, 2 is a positive electrode active material layer, 3 is a positive electrode current collector, 4 is a groove formed in the positive electrode active material layer 2 of the positive electrode 1, at least one end of which is formed up to the end of the positive electrode 1, The angle α formed between the bottom surface portion 5 and the side surface portion 6 of the formed groove 4 is an obtuse angle.

The formation of the groove 4 does not easily damage the positive electrode 1 and the positive electrode current collector plate 3 and easily maintains the shape of the groove 4 even after the formation of the groove 4. And the speed of degassing the generated gas and the speed of drying the solvent of the adhesive can be increased.

The sectional shape of the groove 4 is not particularly limited as long as it has a bottom surface 5 and a side surface 6 and the angle α formed between the bottom surface 5 and the side surface 6 is obtuse. At this time, the flat portion (upper surface) of the positive electrode 1 and the bottom portion 5 of the groove 4 do not necessarily have to be parallel to each other, and the cross-sectional shape of the groove 4 does not need to be constituted only by a straight line, but is rounded. It may have a shape such as taking on.

If the length of the bottom portion 5 of the groove 4 is long, the liquid injection property and the drying property can be improved, but if it is too long, the battery characteristics may be deteriorated. Therefore, it is preferably 1.0 mm or less.
However, if the length is too short, the positions of the upper and lower grooves 4 are likely to shift, so that it is preferably 0.1 mm or more.

The width w of the bottom portion 5 of the upper and lower grooves 4 may be the same, or one of the widths w may be longer. Preferably,
To prevent the position of the upper and lower grooves 4 from shifting,
It is preferable that the width w of the other bottom surface portion 5 is at least 1 times and not more than 3 times the width w of the one bottom surface portion 5. At this time, as shown in the cross-sectional view of FIG. 2, the width w of the bottom surface portion 5 on one of the upper and lower surfaces may be reduced, and the width w of the bottom surface portion 5 on the other surface may be increased, or any of the widths may be randomly selected. There is no particular problem even if the width w of the bottom portion 5 on one surface is reduced and the width w of the bottom portion 5 on the other surface is increased. Further, as shown in the cross-sectional view of FIG. 3, if the width w of the bottom surface portion 5 in one plane is alternately increased, the efficiency of liquid injection and drying is improved.

Further, as the depth direction of the shape of the groove 4, if damage to the electrodes, but a good degree of depth, as shown in the sectional view of FIG. 4, the thickness of the positive electrode 1 t ₁ The thickness of the positive electrode current collector plate 3 is t ₂ , the thickness of the positive electrode 1 in the groove 4 is t ₃ , the porosity P of the positive electrode 1 (active material layer 2), and the lateral expansion due to the compression of the active material layer 2. When the ratio is r ₁ and the elongation in the lateral direction due to the compression of the current collector 3 is r ₂ , if the shape satisfies the following expression (1), the electrode and the current collector are almost damaged. This is preferable because the processing can be performed without any processing. Therefore, when forming a groove by compression such as press working using a projecting mold, the projecting height of the projecting mold is
What is necessary is just to determine according to this formula (1). t ₃ = (t ₁ −t ₂ ) × (1−P) × (1−r ₁ ) + t ₂ × (1−r ₂ ) Equation (1)

The grooves 4 do not necessarily have to be linear as long as at least one end reaches the end of the positive electrode 1. Further, as shown in the plan views of FIGS. May be formed in a parallel line shape, a lattice shape, or an oblique lattice shape (in the drawing, a solid line portion indicates a groove). If the area ratio of the groove 4 to the surface of the positive electrode 1 is large, the injectability and drying property can be improved, but if it is too large, the battery characteristics may be deteriorated.

Next, a method of forming the positive electrode 1 will be described. First, the positive electrode 1 has a positive electrode active material such as a lithium-cobalt composite oxide, a conductive agent, a binder, and a solvent formed on the upper and lower surfaces of a positive electrode current collector 3 made of a conductive metal plate such as an aluminum foil. The positive electrode active material layer 2 is formed by applying the agent pastes and drying them to evaporate the solvent.

Next, grooves 4 are formed on both surfaces of the positive electrode active material layer 2. The method of forming the groove 4 includes, for example, a flat plate pressing process in which flat molds 41 and 42 having a projection 43 are vertically moved as shown in a side view of FIG. 8 and a plan view of FIG. Two roll-shaped dies 51 and 52 having projections 53 as shown in the side view of FIG. 10 and the perspective view of FIG.
A roll-shaped pressing method in which the grooves 4 are formed by passing the positive electrode 1 between them can be applied. In FIGS. 9 and 11, solid lines indicate the protrusions 43 and 53.

The projections 43 and 53 provided on the flat molds 41 and 42 or the roll molds 51 and 52 have a flat upper surface, and the angle between the flat surface and the side surface is obtuse. I have.

The projections 4 having the same shape are formed on both the upper and lower flat molds 41 and 42 or the roll molds 51 and 52.
3 and 53 are formed so that the upper and lower protrusions 43 and 53 overlap each other, and the grooves 4 are formed at the same position on both surfaces of the positive electrode 1 at the same time, so that the positive electrode 1 and the current collector plate 3 are hardly damaged. Further, the effect of making it easy to maintain the shape of the groove 4 even after the formation of the groove 4 is increased.

Further, by setting the ratio of the width of the plane portion in the cross-sectional shape of the overlapping projections 43 and 53 to be 1 time or more and 3 times or less, the opposed grooves on both surfaces of the electrode active material layer applied on both surfaces are formed. Can be reduced, and the deformation of the groove shape can be reduced.

The upper and lower two dies 41, 42 or 5
Positions of the grooves formed so as to be vertically opposed by arranging the planar portions of the projections 43 or 53 so as to be substantially opposed to each other, and making the width of the planar portion in the cross-sectional shape different vertically. Even if the displacement occurs, they are likely to overlap each other, and damage to the positive electrode 1 and the current collector 3 can be reduced.

By setting the angle between the plane portions and the side portions of the projections 43 and 53 to be greater than 90 degrees and 170 degrees or less, it is possible to prevent the periphery of the groove from dropping off at the time of forming the groove and to improve mass productivity. Can be improved.

By setting the width of the flat portion in the cross-sectional shape of the projections 43 and 53 to 0.1 mm or more and 1.0 mm or less, it is possible to maintain the discharge characteristics of the battery while maintaining the discharge rate of the electrolyte and the The drying speed can be increased.

By setting the interval between the adjacent projections 43 and 53 to 20 mm or less, the drying speed of the positive electrode 1 and the injection speed of the electrolyte can be increased.

After the grooves 4 are formed, finally, pressing is performed to a target thickness to smooth the surface of the positive electrode 1 and simultaneously adjust the thickness.

Next, a method for manufacturing a lithium ion battery using the positive electrode 1 in which the groove 4 is formed will be described. First, a negative electrode mixture having a host material capable of occluding and releasing lithium ions such as graphite and a binder is applied to a negative electrode current collector made of a metal current collector such as a copper foil to form a negative electrode. .

Next, each of the negative electrode and the positive electrode 1 having the groove 4 formed therein is cut into a rectangle, and the separator 7, the positive electrode 1, the separator 7, and the negative electrode 8 are cut as shown in the perspective view of FIG. The stacked power generating elements 9 are formed by alternately arranging and overlapping.

As shown in FIG. 13, when the positive electrode 1 must always face the negative electrode 8, the positive electrode 1 is
It is formed in a slightly smaller size, and the negative electrodes 8 are arranged at the upper and lower ends of the laminate, respectively. The separator 7 is provided with a negative electrode 8 for ensuring insulation.
It is formed to have a slightly larger size, and is also arranged above and below the negative electrode 8 arranged at the upper and lower ends of the laminate.
Further, the positive electrode 1, the negative electrode 8, and the separator 7 have their opposing surfaces fixed to each other to integrate the power generating element 9.

The separator 7 is a rectangular sheet made of, for example, a microporous resin film such as polyethylene or polypropylene, and is slightly larger in size than the positive electrode 1 as described above.

In place of the microporous resin film, a porous body made of fine particles such as a metal oxide such as alumina, silica, titanium dioxide, or aluminum nitride, or a metal nitride may be used.

Further, the space between each positive electrode 1 and the separator 7 and the space between each negative electrode 8 and the separator 7 may be fixed by a solution such as an adhesive for fixing both.

As the adhesive or the like, for example, an adhesive resin solution such as polyvinylidene fluoride or polyvinyl alcohol or a resin solution containing alumina, silica, titanium dioxide,
A solution in which a filler such as a metal oxide such as aluminum nitride or a metal nitride is added and dispersed may be used.

Next, as shown in the perspective view of FIG. 14, the laminated power generating element 9 manufactured as described above is covered with an aluminum laminate sheet 10 having a barrier property. Seal the surroundings except for one side. At this time, a lead 11 is connected to each of the positive electrode 1 and each of the negative electrodes 8 of the power generating element 9 in advance, and the lead 11 is securely sealed in a state where the leading end protrudes from the space where the aluminum laminate sheets 10 are overlapped. .

Next, the aluminum laminate sheet 10 is evacuated by being housed in a chamber or the like, thereby extracting air from the inside of the power generation element 9 and injecting a non-aqueous electrolyte into the aluminum laminate sheet 10. Then, by performing pre-charging through the lead 11, the positive electrode 1 and the negative electrode 8
After a gas is generated in between, the vacuum is drawn again to remove the gas, and then the remaining one side of the aluminum laminate sheet 10 is completely sealed and the inside is sealed to complete the lithium ion battery.

In the lithium ion battery of the present embodiment, the positive electrode 1, the negative electrode 8 and the separator 7 are fixed and the power generating element 9 is integrated, so that the power generating element 9 is fixed with a tape or the like or housed in a metal container or the like. Even without pressing, the distance between the positive electrode 1 and the negative electrode 8 can be changed, and the overlap between the electrodes 1 and 8 and the separator 7 can be eliminated. It can be stored in the laminate sheet 10.

Further, in the lithium ion battery of the present embodiment, gas is generated from the positive electrode 1 only at the time of the first charging. Therefore, before the aluminum laminate sheet 10 is completely sealed, the precharging is performed to remove the gas in advance. It is necessary to keep.

Generally, when the gap between the electrodes 1 and 8 of the power generating element 9 and the separator 7 is fixed by an adhesive, when the non-aqueous electrolyte is injected, the gap between the electrodes 1 and 8 and the separator 7 is increased. The non-aqueous electrolyte cannot penetrate into the inside of the power generation element 9, and since the separator 7 uses a microporous resin film or the like, the non-aqueous electrolyte is less likely to permeate than a nonwoven fabric or the like.

However, in this embodiment, the positive electrode 1
Is formed with a plurality of grooves 4, the non-aqueous electrolyte flows through the grooves 4 opened on the side surfaces of the power generating element 9 and enters the inside, and the non-aqueous electrolytic solution in the positive electrode active material layer 2 of the positive electrode 1 around the grooves 4 And quickly penetrates into the negative electrode mixture layer of the negative electrode facing the negative electrode through the separator 7.

In addition, during the evacuation before injecting the non-aqueous electrolyte or during the evacuation after the pre-charging, the air inside the power generating element 9 and the gas generated by the pre-charging are used to form the positive electrode 1. It can be quickly pulled out through the groove 4.

Further, even when the positive electrode 1 and the separator 7 are bonded with an adhesive and dried, the solvent of the adhesive can be quickly evaporated through the groove 4.

As described above, according to the lithium ion battery of the present embodiment, the diffusion rate of the non-aqueous electrolyte into the power generating element 9 is improved, and gas is quickly released from the power generating element 9. Therefore, it is possible to shorten the work time for injecting the non-aqueous electrolyte and the evacuation work, thereby improving the productivity.

Further, since the diffusion of the non-aqueous electrolyte, degassing, and drying of the solvent are rapidly performed, the productivity is improved even if the electrodes 1, 8 and the separator 7 are fixed and the power generating element 9 is integrated. It does not decrease. In addition, by integrally fixing the power generation element 9 with the power generation element 9, the power generation element 9 can be housed in the flexible aluminum laminate sheet 10, and the thickness of the battery container can be reduced, and the battery container can be made lightweight and inexpensive.

In the above embodiment, the positive electrode 1 and the negative electrode 8
Although the description has been given of the case where the and the separator 7 are fixed, the same effect can be obtained even when these are not fixed.

In the above embodiment, the case where the power generating element 9 is stored in the aluminum laminate sheet 10 has been described. However, the present invention is not limited to this, and the power generating element 9 may be stored in another flexible sheet-like battery container. It may be stored in a robust battery container made of a metal can or the like.

In the above embodiment, the groove 4 is provided only in the positive electrode 1. However, if there is no situation that the positive electrode 1 must always face the negative electrode 8, the groove 4 is also provided in the negative electrode 8. The groove 4 can be provided only in the negative electrode 8.

In the above embodiment, the example of the laminated power generating element 9 in which the rectangular positive electrode 1 and the negative electrode 8 are stacked with the separator 7 interposed therebetween as shown in FIG. 13 has been described.
5, a wound power generating element 9 wound between a positive electrode 1 and a negative electrode 8 with a separator 7 interposed therebetween, and an elliptical wound power generating element wound in an elliptical manner between a positive electrode and a negative electrode with a separator interposed therebetween. The present invention is effective when applied to a foldable power generation element which is folded between a positive electrode and a negative electrode with a separator interposed therebetween.

Further, in the above embodiment, the description has been given of the lithium ion battery. However, the present invention is not limited to this, and can be similarly applied to a primary battery or another secondary battery. The configurations of the positive electrode, the negative electrode, and the separator can be arbitrarily changed according to the type of the battery.

[0069]

EXAMPLES More specific examples will be described below. Embodiment 1 FIG. The positive electrode has 90 parts by weight of lithium-cobalt composite oxide (LiCoO ₂ ) as a positive electrode active material, 6 parts by weight of artificial graphite as a conductive agent, and a binder on both sides of a positive electrode current collector plate made of aluminum foil having a thickness of 20 μm. A positive electrode active material layer is formed by applying and drying a positive electrode mixture paste composed of 4 parts by weight of polyvinylidene fluoride (PVDF) and an appropriate amount of N-methylpyrrolidone (NMP) as a solvent, Produced.

The grooves were formed by passing the positive electrode through a roll press type groove processing machine. This grooving machine has a diameter of 250
mm, 400 mm in length, a convex protrusion is formed on the surface of a stainless steel roll in a diagonal lattice shape (intersecting 90 degrees), two rolls are opposed to each other, and a positive electrode is passed between the rolls to form a groove. It is a device that can do. The cross-sectional shape of the protrusion of the roll of this grooving machine is such that the width of the upper surface of the upper roll is 0.3 mm, the width of the lower surface of the protrusion is 0.35 mm, and the height of the protrusion is 30 μm. Is 10m
m, the width of the upper surface of the protrusion of the lower roll is 0.4 mm, the width of the lower surface of the protrusion is 0.45 mm, the height of the protrusion is 30 μm, the cross-sectional shape is trapezoidal, and the distance between the protrusions is 10 mm. When grooves were formed on both sides of the positive electrode by this roll, a groove having a groove bottom width of 0.3 mm and a depth of 30 μm was formed on one side of the positive electrode, and a groove bottom width of 0.3 μm was formed on the other side. A rectangular groove having a thickness of 4 mm and a depth of 30 μm is formed, and the total thickness is 17
It became a positive electrode of 0 μm.

No damage or the like was found on the positive electrode after the formation of the groove, and when the cross section was observed, there was no shift in the position of the groove formation on both surfaces. The groove depth was 25 μm when the positive electrode was subjected to a roll press to make the final thickness 160 μm. No damage or the like was found on the positive electrode after pressing performed for the thickness adjustment. When the cross-section was observed, there was no shift in the position of the groove 4 formed on both surfaces, as shown in the cross-sectional view of FIG. The shape of No. 4 was not deformed. This positive electrode 1 sheet was cut into a width of 100 mm and a length of 150 mm to obtain a positive electrode.

The negative electrode was prepared by adding 90 parts by weight of graphite on both sides of a negative electrode current collector made of a copper foil having a thickness of 15 μm and 10 parts by weight of PVDF as a binder and adding an appropriate amount of NMP as a solvent. Apply each agent paste,
By drying, a negative electrode mixture layer was formed, and further subjected to a roll press to obtain a negative electrode sheet having a final thickness of 160 μm. This negative electrode sheet is 105 mm wide and 155 m long.
m to give a negative electrode.

The separator was prepared by cutting a sheet of a 25 μm-thick polyethylene microporous resin film into a width of 110 mm and a length of 160 mm.

As an adhesive for fixing the positive electrode, the negative electrode and the separator, a paste was prepared by dispersing alumina powder having an average particle diameter of 0.01 μm in a solution of PVDF resin dissolved in NMP.

A negative electrode, a separator, a positive electrode, a separator, and a negative electrode were laminated in this order while applying the above adhesive, and dried in a vacuum dryer set at 80 ° C. while applying pressure to obtain a laminated power generating element. The end of drying at this time was determined when the electric resistance between the positive electrode current collector and the negative electrode current collector reached 100 MΩ. The drying time at this time was 40 minutes.

After the lead terminals were attached to the positive electrode current collector and the negative electrode current collector of the laminated power generating element produced above by a spot welding machine, the laminated power generating element was heat-fused on three sides into a bag shape. Of aluminum carbonate (EC) and diethyl carbonate (DEC) containing 1 mol / l of lithium hexafluorophosphate (LiPF ₆ ) in a vacuum chamber. : An appropriate amount of an electrolyte solution consisting of a solution is poured into a bag, which is evacuated and impregnated with the electrolyte solution under vacuum, precharged, and the generated gas is withdrawn.
The remaining one side was sealed with a heat sealer to obtain a laminated battery.

The rate at which the electrolyte was injected into the stacked power generating element and the rate at which the gas was released were not particularly problematic.

Embodiment 2 FIG. Diameter 250mm, length 400m
Two rolls were used in which convex protrusions were formed in parallel on the surface of a stainless steel roll. The cross-sectional shape of the protrusion of the upper roll is such that the width of the protrusion upper surface is 0.3 mm and the width of the protrusion lower surface is 0.3 mm.
5mm, protrusion height 30μm, protrusion spacing 10mm
The cross-sectional shape of the lower roll is such that the width of the upper surface of the protrusion is 0.3 mm, the width of the lower surface of the protrusion is 0.35 mm, the height of the protrusion is 30 μm, the cross-sectional shape is rectangular, and the distance between the protrusions is 10 m.
m. A laminated battery was manufactured in the same manner as in Example 1 except for the formation of the groove.

When grooves were formed on both surfaces of the positive electrode with this roll, a groove having a groove bottom width of 0.3 mm and a depth of 30 μm was formed on one surface of the positive electrode, and a groove bottom surface was formed on the other surface. A rectangular groove having a width of 0.3 mm and a depth of 30 μm was formed, and a positive electrode having an overall thickness of 170 μm was obtained.

No damage or the like was found on the positive electrode after the formation of the groove.
There was a displacement of 15 mm. If the widths of the upper and lower grooves are the same, misalignment is likely to occur when forming the grooves. This positive electrode was roll-pressed to a final thickness of 160 μm, resulting in a groove depth of 25 μm. No damage or the like was found on the positive electrode after pressing performed for the thickness adjustment, but when the cross-section was observed, as shown in the cross-sectional view of FIG.
Since there was a shift in the groove formation position on both surfaces, the groove shape was deformed.

Using this positive electrode sheet, a laminated power generating element was assembled and dried in the same manner as in Example 1. The drying time at this time was 45 minutes. The rate at which the electrolyte was injected into the stacked power generating element and the rate at which gas was released were not particularly problematic. Since the groove shape was deformed, the cross-sectional area of the groove was reduced and the drying speed and the like were slightly reduced, but there was no problem.

Comparative Example 1 In the same manner as in Example 1, a roll having convex protrusions formed in an oblique lattice shape (intersecting at 90 degrees) was used.
The cross-sectional shape of the protrusion of the upper roll is such that the width of the upper surface of the protrusion is 0 mm, the width of the lower surface of the protrusion is 0.3 mm, and the height of the protrusion is 30 μm. As for the shape, the width of the upper surface of the projection is 0 mm, the width of the lower surface of the projection is 0.3 mm, the height of the projection is 30 μm, the cross section is wedge-shaped, and the interval between the projections is 10 mm. Except for the formation of the groove, the same procedure as in Example 1 was performed.

When grooves were formed on both sides of the positive electrode with this roll, the positive electrode was cut at the grooves, and was severely damaged, making it impossible to finish the battery.

Comparative Example 2 The protrusion height of the upper and lower rolls used in Example 1 was changed to 40 μm, and the groove was formed by using a roll having the same other protrusion shape dimensions as in Example 1.

When grooves were formed on both surfaces of the positive electrode with this roll, a groove having a groove bottom width of 0.3 mm and a depth of 40 μm was formed on one surface of the positive electrode, and a groove bottom surface was formed on the other surface. A rectangular groove having a width of 0.4 mm and a depth of 40 μm was formed, and a positive electrode having an overall thickness of 170 μm was obtained.

After the formation of the groove, the positive electrode had many irregularities on the surface, and when the cross section was observed, it was observed that the current collector plate was greatly deformed and damaged. This is because the height of the protrusion was too high in the formation of the upper and lower grooves, and compression was performed to the above formula (1) or more, thereby damaging the electrode and the current collector.

Embodiment 3 FIG. The groove was formed by changing the width of the protrusion shape and the interval (pitch) of the protrusions of the groove forming roll used in Example 1. A laminated battery was prepared in the same manner as in Example 1 except for the formation of the groove, and the relationship between the groove width and the drying time and the discharge capacity, the relationship between the groove interval and the drying time, and the relationship between the groove area ratio in the plane and the discharge capacity. Investigated the relationship.

FIG. 18 is a diagram showing the relationship between the groove width, the drying time, and the discharge capacity. As shown in FIG. 18, when the groove width is narrow, the drying time tends to be long. When the groove width is 0.1 mm or less, the drying time exceeds 60 minutes, so that it takes too much time. As the groove width increases, the discharge capacity tends to decrease. If the groove width exceeds 1.0 mm, the discharge capacity becomes smaller than 80%, which causes a problem. Also,
When the groove width is 0.1 mm or less, misalignment tends to occur in the groove formation, and the groove formation becomes difficult. This result indicates that the groove width is preferably 0.1 mm or more and 1.0 mm or less.

FIG. 19 is a diagram showing the relationship between the groove interval and the drying time when the groove width is fixed at 0.3 mm. FIG.
As shown in Table 2, it was found that the drying time tended to be longer when the groove interval was wide, and that the drying time exceeded 60 minutes when the groove interval was larger than 20 mm. Therefore, the groove interval is preferably 20 mm or less.

FIG. 20 is a diagram showing the relationship between the groove area ratio in the plane and the discharge capacity. As shown in FIG. 20, when the groove area ratio exceeds 20%, the discharge capacity of the battery falls below 80%. Therefore, the area ratio occupied in the plane of the groove is preferably 20% or less.

Embodiment 4 FIG. In the same manner as in Example 1, a roll having convex protrusions formed in an oblique lattice shape (intersecting at 90 degrees) was used.
The cross-sectional shape of the projections of the upper and lower rolls is such that the projection height is 30 μm, the angle between the bottom surface and the side surface is 145 degrees, and the interval between the projections is 1.
The cross-sectional shape of 0 mm is trapezoidal, and the groove width ratio, that is, the upper and lower rolls in which the ratio of the groove width of the upper roll to the groove width of the lower roll opposed to the groove of the upper roll is changed from 1 to 4. A groove was formed by using the above method. Specifically, when the groove width of the upper roll is 0.3 mm, the groove width of the lower roll is 0.3 mm, the groove width of the upper roll is 0.2 mm, and the groove width of the lower roll is 0.4 mm. , Groove width of upper roll 0.15m
m, when the groove width of the lower roll is 0.45 mm, the groove width of the upper roll is 0.12 mm, and the groove width of the lower roll is 0.48 m.
When m was set, the groove was formed with the groove cross-sectional area being substantially constant.

In the groove shape after the formation of the groove, the larger the groove width of one roll, the greater the deformation of the groove with the larger groove width and the smaller the groove depth. FIG. 21 is a diagram showing the relationship between the groove width ratio and the drying time. As shown in FIG. 21, when the groove width ratio is larger than 1: 3, the drying time is longer than 60 minutes, and the drying time is longer. It turns out that it takes too much. Therefore, the ratio of the groove width is preferably set to 1: 3 or less.

Comparative Example 3 Using the upper roll and the lower roll used in Example 2, grooves were formed by shifting the lower roll by 0.45 mm in the groove width direction.

At this time, a groove having a groove bottom width of 0.3 mm and a depth of 30 μm is formed on one surface of the positive electrode, and a groove bottom width of 0.3 mm and a depth of 30 μm is formed on the other surface. A rectangular groove was formed, and a positive electrode having a total thickness of 170 μm was obtained.

After the formation of the grooves, irregularities appeared on the surface of the positive electrode, and some portions were cut at the grooves. When the cross-section is observed, as shown in the cross-sectional view of FIG.
Since the groove formation position is shifted by about 0.3 mm and the upper and lower grooves 4 are completely shifted, the current collector 3 is partially damaged,
It has been found that when completely deviated vertically, it cannot be used as one positive electrode.

Embodiment 5 FIG. In the same manner as in Example 1, a roll having convex protrusions formed in an oblique lattice shape (intersecting at 90 degrees) was used.
As for the cross-sectional shape of the roll, the width of the upper surface of the protrusion is fixed to 0.3 mm, and the angle between the upper surface of the protrusion and the side surface is changed to form a groove. The relationship with the drying rate was investigated.

FIG. 23 is a diagram showing the relationship between the groove side surface angle and the drying speed. As shown in FIG. 23, the drying time tends to become longer at an angle of 150 ° or more.
When the temperature exceeds 0 ° C., the drying time is rapidly increased. Therefore, the groove side surface angle is preferably 170 degrees or less. Angle 170
It is understood that the reason why the drying time is drastically increased when the temperature exceeds the degree is that the groove is crushed and the groove cross-sectional area is reduced at the time of press working for thickness adjustment after the groove processing. Was.

Embodiment 6 FIG. The positive electrode sheet prepared in Example 1 was cut into a width of 50 mm and a length of 250 mm to form a positive electrode. The negative electrode sheet prepared in Example 1 was cut into a width of 52 mm and a length of 300.
mm to obtain a negative electrode.

The same separator as in Example 1 was used with a width of 54 mm.
While cutting to a length of 305 mm, the same adhesive as in Example 1 was applied to each surface of the positive electrode and the negative electrode,
A positive electrode, a separator, and a negative electrode were overlapped and wound to form a wound electrode body. The wound electrode body was dried in a vacuum dryer set at 80 ° C. to obtain a wound power generating element. The drying time at this time was 40 minutes.

After the lead terminal was attached to the above-prepared wound power generating element by a spot welder, the lead terminal was put in an aluminum can, an appropriate amount of the same electrolytic solution as in Example 1 was injected, and the electrolytic solution was evacuated to a vacuum. After impregnation, the battery was pre-charged, the generated gas was extracted, and then sealed to obtain a cylindrical wound battery.

The speed at which the electrolyte was injected into the cylindrical winding type power generating element and the speed at which the gas was released were not particularly problematic. The battery characteristics of this cylindrically wound battery were the same as those of the prior art.

Embodiment 7 FIG. The positive electrode sheet prepared in Example 1 was cut into a width of 50 mm and a length of 250 mm to form a positive electrode. The negative electrode sheet prepared in Example 1 was cut into a width of 52 mm and a length of 300.
mm to obtain a negative electrode.

A separator similar to that of Example 1 was formed with a width of 54 mm.
While cutting to a length of 305 mm, the same adhesive as in Example 1 was applied to each surface of the positive electrode and the negative electrode,
The positive electrode, the separator, and the negative electrode are overlapped and wound in an elliptical shape to produce an elliptical wound electrode body, and the elliptical wound electrode body is dried while being pressed in a vacuum dryer set at 80 ° C. And a flat wound power generating element. The drying time at this time was 40 minutes.

A lead terminal was attached to the flat-wound power generating element produced above by a spot welder, and the three sides were heat-sealed and placed in a bag-shaped aluminum laminate sheet. After injecting an appropriate amount of the solution, evacuating the solution and impregnating the electrolyte with a vacuum, pre-charging, extracting the generated gas, sealing the remaining side with a heat fusion machine, and winding it flat Type battery.

The rate at which the electrolyte was injected into the flat wound power generating element and the rate at which gas was released did not matter.
The battery characteristics of the flat-wound battery were the same as those of the conventional battery.

[0106]

According to the first battery of the present invention, there is provided a battery having a power generating element in which positive and negative electrodes having electrode active material layers on both surfaces of a current collector are disposed via an electrolyte holding layer. A plurality of grooves each having at least one end reaching an end of the electrode are formed in both electrode active material layers of at least one of the positive and negative electrodes, and the cross-sectional shape of the groove has a side surface portion and a bottom surface portion; Since the angle between the portion and the side portion is an obtuse angle, it is difficult to damage the electrodes and the current collector plate in forming the groove,
Also, since the shape of the groove is easily maintained even after the groove is formed,
It is possible to increase the permeation speed of the electrolytic solution, the degassing speed of the generated gas, and the drying speed of the adhesive solvent.

In the second battery according to the present invention, since the bottom surfaces of the grooves of both electrode active material layers are formed so as to overlap each other, both surfaces of the electrode active material layer coated on both surfaces are opposed to each other. When the misalignment between the grooves occurs, damage to the electrodes and the current collector can be reduced.

In the third battery according to the present invention, the bottoms of the grooves of both electrode active material layers are formed at positions substantially opposite to each other, and the widths of the bottoms in the cross-sectional shapes of the grooves of both electrode active material layers are different. Therefore, even if the opposing grooves are displaced, they are likely to overlap each other, and damage to the electrodes and the current collector can be reduced.

According to the fourth battery of the present invention, the thickness of the grooved electrode is t ₁ , the thickness of the current collector plate of the electrode is t ₂ , and the thickness of the electrode in the groove is t. _{3. When} the porosity of the active material layer of the electrode is P, the lateral elongation by compression of the active material layer is r ₁ , and the lateral elongation by compression of the current collector plate is r _2. , the shape of the groove, since it satisfies the following formula _{(1), t 3 = (} t 1 -t 2) × (1-P) × (1-r 1) + t 2 × (1-r 2 Formula (1) Even if the groove is formed by compressing the electrode active material layer, an excessive pressure is not applied to the current collector, so that the current collector is not greatly deformed or damaged.

According to the fifth battery of the present invention, since the angle between the bottom surface and the side surface is greater than 90 degrees and 170 degrees or less, it is possible to prevent the periphery of the groove from falling off when the groove is formed. Mass productivity can be improved.

According to the sixth battery of the present invention, the width of the bottom surface in the cross-sectional shape of the groove is 0.1 mm or more and 1.0 mm or less.
mm or less, while maintaining the discharge characteristics of the battery,
The injection rate and drying rate of the electrolyte can be increased.

According to the seventh battery of the present invention, since the ratio of the width of the bottom surface in the cross-sectional shape of the overlapping groove is not less than 1 and not more than 3 times, the both sides of the electrode active material layer applied on both sides are possible. The displacement between the opposed grooves is reduced, and the deformation of the groove shape can be reduced.

According to the eighth battery of the present invention, the interval between adjacent grooves is 20 mm or less, so that the electrode drying speed and the electrolyte injection speed can be increased.

According to the ninth battery of the present invention, since the ratio of the area of the groove to the surface area of the electrode active material layer is 20% or less, the discharge characteristics of the battery are maintained, and the drying speed and the electrode The injection speed of the electrolyte can be increased.

According to the tenth battery of the present invention, at least one of the positive electrode and the electrolyte holding layer and the negative electrode and the electrolyte holding layer are fixed by the adhesive layer. It is possible to supply a battery that is lightweight and has excellent mass productivity.

According to the first electrode forming method according to the present invention, the power generation element is provided in which the positive and negative electrodes having the electrode active material layers on both sides of the current collector are arranged via the electrolyte holding layer. In the electrode forming method for a battery, the two-electrode active material layer of the electrode is provided with a mold having a flat portion formed on an upper portion and a protrusion formed by a side portion formed at an obtuse angle with the flat portion. Since the grooves are formed by pressing from both sides of the electrode active material layer, it is difficult to damage the electrodes and the current collector plate during the formation of the grooves, and it is easy to maintain the shape of the grooves even after the formation of the grooves. It is possible to increase the liquid permeation speed, the degassing speed of generated gas, and the drying speed of the adhesive solvent.

According to the second electrode forming method of the present invention, the thickness of the electrode forming the groove is t ₁ , the thickness of the current collector plate of the electrode is t ₂ , and the thickness of the electrode in the groove is the thickness of the electrode. t ₃ , the porosity of the active material layer of the electrode is P, the elongation in the horizontal direction due to compression of the electrode active material layer is r ₁ , and the elongation in the horizontal direction due to compression of the current collector is r ₂ . In some cases, the height of the protrusion is formed so that the shape of the groove satisfies the following expression (1), so that t ₃ = (t ₁ −t ₂ ) × (1-P) × (1 −r ₁ ) + t ₂ × (1−r ₂ ) Equation (1) Even if the electrode active material layer is compressed to form a groove, the current collector is not excessively pressed, and the current collector is greatly deformed. , No damage.

According to the third electrode forming method of the present invention, the ratio of the surface area of the projection to the surface area of the electrode active material layer is set to 20% or less, so that the discharge characteristics of the battery can be maintained. In addition, the electrode drying speed and the electrolyte injection speed can be increased.

According to the first electrode forming apparatus of the present invention, the power collecting element in which the positive and negative electrodes having the electrode active material layers on both sides of the current collector plate are arranged via the electrolyte holding layer is provided. In the electrode forming apparatus for a battery, two dies are disposed with the electrode interposed therebetween, and two molds each having a flat portion formed on an upper portion and a protrusion formed by a side portion formed at an obtuse angle with the flat portion, and Since the mold is provided with a mold driving unit that compresses the electrode active material layer by pressing the mold from both sides of the electrode, it is difficult to damage the electrode and the current collector plate in forming the groove, Since the shape of the groove can be easily maintained even afterward, the permeation speed of the electrolytic solution, the degassing speed of the generated gas, and the drying speed of the solvent of the adhesive can be increased.

According to the second electrode forming apparatus of the present invention, the flat portions of the projections of the two dies are arranged so as to overlap each other. Thus, damage to electrodes and current collectors can be reduced.

According to the third electrode forming apparatus of the present invention, the ratio of the width of the plane portion in the cross-sectional shape of the overlapping projections is not less than 1 times and not more than 3 times. In this case, the displacement between the opposed grooves on both sides of the groove can be reduced, and the deformation of the groove shape can be reduced.

According to the fourth electrode forming apparatus of the present invention, the flat portions of the projections of the two dies are arranged so as to be substantially opposed to each other, and the width of the flat portion in the cross-sectional shape is different. Therefore, even if the misalignment of the opposing grooves occurs, the grooves easily overlap each other, and damage to the electrodes and the current collector can be reduced.

According to the fifth electrode forming apparatus of the present invention, the angle between the flat portion and the side portion of the projection is greater than 90 degrees and 170 degrees or less, so that the periphery of the groove may not fall off when the groove is formed. It can be suppressed, and mass productivity can be improved.

According to the sixth electrode forming apparatus of the present invention, the width of the flat portion in the cross-sectional shape of the projection is 0.1 m.
m or more and 1.0 mm or less, it is possible to increase the rate of injecting and drying the electrolyte while maintaining the discharge characteristics of the battery.

According to the seventh electrode forming apparatus of the present invention, the interval between adjacent projections is 20 mm or less, so that the electrode drying speed and the electrolyte injection speed can be increased.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention,
It is sectional drawing which shows the shape of the electrode which performed groove processing.

FIG. 2 shows an embodiment of the present invention,
It is sectional drawing which shows the shape of the electrode which performed groove processing.

FIG. 3 shows an embodiment of the present invention,
It is sectional drawing which shows the shape of the electrode which performed groove processing.

FIG. 4 shows an embodiment of the present invention,
It is sectional drawing explaining the cross-sectional dimension of the electrode which performed groove processing.

FIG. 5 shows an embodiment of the present invention,
It is a top view which shows the groove pattern of the electrode which performed groove processing.

FIG. 6 shows an embodiment of the present invention,
It is a top view which shows the groove pattern of the electrode which performed groove processing.

FIG. 7 shows an embodiment of the present invention,
It is a top view which shows the groove pattern of the electrode which performed groove processing.

FIG. 8 shows an embodiment of the present invention,
It is a side view which shows groove processing by a flat plate press typically.

FIG. 9 shows an embodiment of the present invention,
It is a top view which shows the die surface of the groove processing by a flat plate press.

FIG. 10, showing an embodiment of the present invention, is a side view schematically illustrating groove processing by a roll-shaped press.

FIG. 11, showing an embodiment of the present invention, is a perspective view illustrating a surface of a roll die for groove processing by a roll press.

FIG. 12, showing an embodiment of the present invention, is an exploded perspective view showing an electrode and a separator of a nonaqueous electrolyte secondary battery.

FIG. 13, showing an embodiment of the present invention, is a longitudinal sectional view illustrating a structure of a laminated nonaqueous electrolyte secondary battery.

FIG. 14, showing an embodiment of the present invention, is a perspective view illustrating a non-aqueous electrolyte secondary battery in which a power generation element is sealed with an aluminum laninate sheet.

FIG. 15, showing an embodiment of the present invention, is a longitudinal sectional view illustrating a structure of a power generating element of a wound nonaqueous electrolyte secondary battery.

FIG. 16 shows the first embodiment of the present invention, and is a cross-sectional view showing a groove shape of a grooved electrode.

FIG. 17 shows the second embodiment of the present invention, and is a cross-sectional view showing a groove shape of a grooved electrode.

FIG. 18 illustrates Example 3 of the present invention, and is a diagram illustrating a relationship between a groove width, a drying time, and a discharge capacity.

FIG. 19, showing Example 3 of the present invention, is a diagram illustrating a relationship between a groove interval and a drying time.

FIG. 20 illustrates Example 3 of the present invention, and is a diagram illustrating a relationship between a groove area ratio and a discharge capacity.

FIG. 21 illustrates Example 4 of the present invention, and is a diagram illustrating the relationship between the ratio of the upper and lower groove widths and the discharge capacity.

FIG. 22 shows the fifth embodiment of the present invention, and is a cross-sectional view showing the shape of a grooved electrode.

FIG. 23, showing Example 6 of the present invention, is a diagram illustrating the relationship between the groove side surface angle and the drying time.

[Explanation of symbols]

1 positive electrode, 2 positive electrode active material layer, 3 positive electrode current collector plate, 4
Groove, 5 bottom part, 6 side parts, 7 separator, 8 negative electrode, 9 laminated power generation element, 10 aluminum laminated sheet, 11 terminals, 12 outer can, 41 flat upper mold, 42 flat lower mold, 43 , 53 Projection, 51
Roll-shaped upper mold, 52 roll-shaped lower mold.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisashi Shioda 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Atsushi Arakane 2-3-2 Marunouchi 3-chome, Chiyoda-ku, Tokyo Rishi Electric Co., Ltd. (72) Inventor Takashi Nishimura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Junichi Hosokawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric (72) Inventor Shoji Yoshioka 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Makiko Yoshise 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Co., Ltd. Inside the company (72) Inventor Akira Shirakami 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Daigo Takemura Maru, Chiyoda-ku, Tokyo 2-3-2 Uchi, Mitsubishi Electric Co., Ltd. (72) Hironori Kuriki, 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term 5H024 AA01 AA02 BB05 BB18 BB19 BB20 CC02 CC04 CC12 DD15 HH00 HH01 HH13 HH15 5H028 AA06 BB03 BB04 BB05 BB15 BB17 BB19 CC07 CC08 HH00 HH01 HH05 5H029 AJ14 AK03 AL07 AM03 AM05 AM07 BJ02 BJ04 BJ12 BJ14 CJ03 CJ06 HJ01 HJ05 H08 FA02 FA05 FA10 FA15 GA03 GA08 GA27 GA29 GA30 HA00 HA04 HA09 HA12

Claims (20)

[Claims] 1. A battery provided with a power generating element in which positive and negative electrodes having electrode active material layers on both sides of a current collector are disposed via an electrolyte holding layer, at least one of the positive and negative electrodes. In the active material layer, a plurality of grooves having at least one end reaching the end of the electrode are formed, and the cross-sectional shape of the groove has a side surface and a bottom surface, and an angle formed by the bottom surface and the side surface is obtuse. A battery comprising: 2. The battery according to claim 1, wherein the bottom surfaces of the grooves of both electrode active material layers are formed so as to overlap with each other. 3. A method according to claim 1, wherein the bottom surfaces of the grooves of both electrode active material layers are formed at substantially opposing positions, and the widths of the bottom surfaces in the cross-sectional shapes of the grooves of both electrode active material layers are different. Item 7. The battery according to Item 1. 4. The thickness of the electrode in which the groove is formed is t ₁ , the thickness of the current collector plate of the electrode is t ₂ , the thickness of the electrode in the groove is t ₃ , and the thickness of the electrode active material layer of the electrode is When the porosity is P, the lateral elongation by compression of the electrode active material layer is r ₁ , and the lateral elongation by compression of the current collector plate is r ₂ , the shape of the groove is as follows: 2. The battery according to claim 1, wherein the battery satisfies Expression (1). t ₃ = (t ₁ −t ₂ ) × (1−P) × (1−r ₁ ) + t ₂ × (1−r ₂ ) Equation (1) 5. The method according to claim 1, wherein the angle between the bottom surface and the side surface is greater than 90 degrees and equal to or less than 170 degrees.
The battery as described. 6. The width of the bottom surface in the cross-sectional shape of the groove is 0.
The battery according to claim 1, wherein the length is 1 mm or more and 1.0 mm or less. 7. The battery according to claim 2, wherein the ratio of the width of the bottom surface in the cross-sectional shape of the overlapping groove is not less than 1 and not more than 3 times. 8. The battery according to claim 1, wherein an interval between adjacent grooves is 20 mm or less. 9. The battery according to claim 1, wherein the ratio of the area of the groove to the surface area of the electrode active material layer is 20% or less. 10. The battery according to claim 1, wherein at least one of the positive electrode and the electrolyte holding layer and / or the negative electrode and the electrolyte holding layer are fixed by an adhesive layer. 11. A method of forming an electrode of a battery comprising a power generating element in which positive and negative electrodes having electrode active material layers on both surfaces of a current collector plate are disposed via an electrolyte holding layer, wherein both electrodes of said electrode are formed. On the active material layer, a mold having a projection formed of a flat portion at the top and a side portion formed at an obtuse angle with the flat portion is pressed from both sides of the electrode active material layer to form a groove. A method for forming an electrode, comprising: forming an electrode; 12. The thickness of the electrode forming the groove is t ₁ , the thickness of the current collector plate of the electrode is t ₂ , the thickness of the electrode in the groove is t ₃ , and the porosity of the active material layer of the electrode is t ₁ . P, when the elongation in the lateral direction due to the compression of the electrode active material layer is r ₁ and the elongation in the lateral direction due to the compression of the current collector plate is r ₂ , the shape of the groove is represented by the following formula ( The method of forming an electrode according to claim 11, wherein the height of the protrusion is formed so as to satisfy 1). t ₃ = (t ₁ −t ₂ ) × (1−P) × (1−r ₁ ) + t ₂ × (1−r ₂ ) Equation (1) 13. The method for forming an electrode according to claim 11, wherein the ratio of the area of the flat portion of the projection to the surface area of the electrode active material layer is 20% or less. 14. An electrode forming apparatus for a battery including a power generation element having a positive electrode and a negative electrode having electrode active material layers on both surfaces of a current collector plate with an electrolyte holding layer interposed therebetween. Two molds are arranged and formed with a projection formed of a flat portion on the top and a side portion formed at an obtuse angle with the flat portion, and the mold is pressed from both sides of the electrode. An electrode forming apparatus, comprising: a mold driving unit for compressing the electrode active material layer. 15. The method according to claim 1, wherein the flat portions of the protrusions of the two molds are arranged so as to overlap with each other.
5. The electrode forming apparatus according to 4. 16. The electrode forming apparatus according to claim 15, wherein the ratio of the width of the flat portion in the cross-sectional shape of the overlapping projection is not less than 1 and not more than 3 times. 17. The electrode forming apparatus according to claim 14, wherein the flat portions of the projecting portions of the two molds are arranged so as to substantially face each other, and the widths of the flat portions in the cross-sectional shape are different. 18. The electrode forming apparatus according to claim 14, wherein the angle between the flat portion and the side portion of the projection is greater than 90 degrees and 170 degrees or less. 19. The electrode forming apparatus according to claim 14, wherein the width of the plane portion in the cross-sectional shape of the projection is 0.1 mm or more and 1.0 mm or less. 20. The electrode forming apparatus according to claim 14, wherein an interval between adjacent projections is 20 mm or less.