JP2009218105A - Stacked battery and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stacked battery free from position deviations at positive and negative electrodes. <P>SOLUTION: The stacked battery has an angular battery element, having a planar positive electrode, a separator, and a planar negative electrode stacked in this order. One side of the battery element works as the leading side of a terminal connector formed on each of the positive and negative electrodes, with both a planar positive-electrode connector in the positive electrode and a planar negative-electrode connector in the negative electrode being led out therefrom; the projecting plane vertically projecting the positive-electrode connector on the surface, in the extending direction of the positive electrode, does not mutually intersect with the plane projecting the negative-electrode connector on the surface in the extending direction of the negative electrode; the opposite areas of the positive and negative electrodes are different in size; each of the positive and negative electrodes is arranged to position in the electrode surface of the larger area in a projecting unit, where the electrode of the smaller area is projected to the surface opposite to the electrode of the larger area; and a knocking unit is provided in the separator, to knock the ends of the positive and negative electrodes so as to regulate the movement of both electrodes, and the separator is connected to the knocking unit by the folded line or the connecting portion of the adjoining separators from among the separators disposed in each of the electrode surfaces. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a battery sealed with a film-shaped packaging material, and relates to a laminated battery in which a battery element in which a predetermined number of flat plate-like positive electrodes and negative electrodes are laminated together with a separator is sealed with a film-shaped packaging material. .

  Lithium ion batteries having a large charge / discharge capacity are widely used in portable battery-powered devices such as mobile phones. In addition, in applications such as electric vehicles, electric bicycles, electric tools, and power storage, secondary batteries having a large charge / discharge capacity and excellent efficiency are required.

In these high-power batteries, in order to increase the energy density per unit volume or mass of the battery, it is possible to reduce the thickness of the outer packaging of the battery in place of an iron-based material or aluminum material. It is effective to use materials.
Film-like exterior materials such as polypropylene film and polyethylene film that have corrosion resistance to electrolytes and good heat-fusibility and can prevent electrolyte, moisture and gas permeation A laminated film obtained by laminating and laminating a metal foil such as an aluminum foil and a protective film having a high strength such as nylon or polypropylene is used.

In a laminated lithium ion battery coated with a film-shaped exterior material, the surroundings were heat-sealed with the film-shaped exterior material leaving an opening for injection of the electrolyte, and then the internal gas was sucked and decompressed. In the state, the opening is heat sealed and sealed.
When sealing in a reduced pressure state, the film-shaped packaging material is pressed against the battery element by the atmospheric pressure, and the positive electrode and the negative electrode are brought into close contact via the separator. That is, the battery-like exterior material is pressed against the battery element with a large force of 0.1 MPa by atmospheric pressure. As a result, the positive electrode, the separator, and the negative electrode are in close contact with each other. However, depending on the friction coefficient between the positive electrode, the negative electrode, and the separator and the gas generation state inside the battery, the pressing force due to atmospheric pressure does not work effectively. It also happened.

  In addition, in a stacked battery such as a stacked lithium ion battery, the negative electrode has a larger outer shape than the positive electrode, and all the projections on the negative electrode side of the positive electrode are arranged on the negative electrode surface. However, when the positive electrode and the negative electrode are misaligned, the relative positional relationship between the positive electrode and the negative electrode is deviated, which may cause problems such as deterioration of battery characteristics.

In order to maintain such a positional relationship between the positive electrode and the negative electrode, a stacked type battery in which both the positive electrode and the negative electrode are covered with a separator so that the outer dimensions of the positive electrode and the negative electrode are equal to each other so that positional displacement is unlikely to occur. Has been proposed (see, for example, Patent Document 1).
However, as a result of arranging two separators between the positive electrode and the negative electrode, there is a problem that the distance between the electrodes increases and the electrical resistance between the electrodes increases.

In addition, there has been proposed a stacked battery in which a plurality of separators are fixed to each other at part or all of the peripheral portions of the positive electrode and the negative electrode to fix the electrode group and prevent positional deviation (see, for example, Patent Document 2). ).
However, in a battery having a large number of positive and negative electrodes and a large charge / discharge capacity, it is necessary to make the welded portion of the separator protrude greatly to the periphery, and a space is created between the battery element and the exterior material. There was a problem that volumetric efficiency was lowered.
JP 2000-315489 A JP-A-10-64506

  The present invention relates to a stacked battery in which a battery element in which a positive electrode and a negative electrode having different areas are stacked with a separator interposed therebetween, such as a stacked lithium ion battery, is sealed with a film-like exterior material. Even when added, the object is to solve the problem that the battery characteristics deteriorate due to the negative electrode being displaced inside the battery and causing the positive electrode to have a portion that does not oppose the negative electrode. It is an object to achieve without causing a decrease in efficiency. Another object of the present invention is to provide a stacked battery in which the positioning of both the positive electrode and the negative electrode can be realized with high accuracy in the battery element assembly process.

  The present invention has a plate-shaped positive electrode terminal, a separator, and a rectangular battery element in which a plate-shaped negative electrode is laminated, and one surface of the battery element is provided on each of the positive electrode and the negative electrode. The terminal connecting portion lead-out surface from which both the connecting portion and the plate-like negative electrode terminal connecting portion are drawn, and the projection planes obtained by projecting the positive electrode terminal connecting portion and the negative electrode terminal connecting portion perpendicularly to the surfaces extending the positive electrode and the negative electrode are The positive electrode and the negative electrode, which do not cross each other, have different areas of the surfaces facing each other, and the projections obtained by projecting the electrodes having the smaller area onto the surfaces facing the electrodes having the larger area are all the electrodes on the larger side. Respective electrodes are arranged so as to be located on the surface, and the separator is provided with an abutting portion that abuts the positive electrode end surface and the negative electrode end surface to restrict the movement of the positive electrode and the negative electrode. A laminated type formed by folds or joints between adjacent separators among the separators arranged on the pole face, and all separators laminated on the electrode face are joined by the folds or joints. It is a battery.

Further, the electrode having the smaller area is wrapped with a bag-shaped separator, and the abutting portion is formed by a joining portion of adjacent bag-shaped separators, and the electrode having a smaller area is positioned at the abutting portion. It is a stacked battery.
In the stacked battery, the contact portion that restricts the movement of the electrode having the large area is a fold of the separator, and the contact portion that restricts the movement of the electrode having the small area is the joint portion of the separator.
The electrode having a small area is the above-described stacked battery that is surrounded by a junction of separators on two sides adjacent to the side located on the terminal connecting portion lead-out surface.

In addition, the separator is made of a zigzag-shaped member in which a zigzag fold portion is located on the terminal connection portion lead-out surface, and the fold portion has an opening through which the positive electrode terminal connection portion or the negative electrode terminal connection portion passes. It is.
The separator is formed of a zigzag-like member in which a zigzag fold portion is positioned on a surface other than the terminal connection portion lead-out surface, and the electrode is positioned by the abutting portion formed by joining formed at a position perpendicular to the fold. It is a stacked battery.
In the laminated battery described above, the separator joint is a continuous linear or intermittent one formed by any one of welding, an adhesive, and an adhesive tape.
The separator or electrode located in the outermost layer is the above-described laminated battery that is bonded to a fixing tape disposed on the side opposite to the terminal connection portion drawing surface of the battery element.

A plate-like positive electrode provided with a plate-like positive electrode terminal connecting portion and a plate-like negative electrode provided with a plate-like negative electrode terminal connecting portion are arranged such that the positive electrode terminal connecting portion and the negative electrode terminal connecting portion face the same direction. The positive electrode and the negative electrode were laminated with a separator disposed on the electrode surface so that the surfaces of the positive electrode terminal connection portion and the negative electrode terminal connection portion projected perpendicularly to the surfaces of the positive electrode and the negative electrode extended did not cross each other. Later, at least one of the positive electrode terminal connection portion and the negative electrode terminal connection portion is heated to thermally bond the adjacent separator, thereby forming an abutting portion that restricts movement of at least one of the positive electrode and the negative electrode. It is a manufacturing method of a laminated battery.
After the electrode having the smaller electrode area is accommodated in the bag-shaped separator and the plate-shaped electrode terminal connection portion bonded to the current collector is taken out, at least a part of the opening of the bag-shaped separator other than the portion is joined, The electrode end face with a large area is regulated by heating the terminal connection part of the electrode with a small area or the current collector side of the electrode, and heat-sealing the separator. It is a manufacturing method of the laminated battery which forms a butting part.

  In the present invention, the separator is provided with positive and negative electrode positioning means and all the separators are connected. Therefore, in a stacked battery such as a lithium ion battery, the positions of the positive electrode and the negative electrode are excessive in any direction. The battery characteristics can be prevented from deteriorating due to impact or vibration, and high-accuracy positioning can be realized even when the battery is manufactured, which has a great effect on battery productivity.

  The present invention relates to a problem that a battery performance is deteriorated between a positive electrode and a negative electrode in a laminated battery such as a laminated lithium ion battery sealed with a film-like packaging material. By forming a blocking portion that restricts the movement of the positive electrode and the negative electrode in the separator that is positioned, there is no deviation in the positional relationship between the positive electrode and the negative electrode, and there is no increase in volume, and a stacked battery with good volume efficiency is obtained. It has been found that it can be provided.

In addition, in the case where a positive electrode lead terminal and a negative electrode lead terminal are taken out from a sealing portion provided on the same side of a rectangular stacked battery, when connecting a large number of stacked batteries in series and parallel, It has a feature that the degree of freedom of battery arrangement is large.
However, between the positive electrode lead terminal and the negative electrode lead terminal, the film connection material is placed on the battery element by the atmospheric pressure applied to the film external material between the film connection material located on the opposite side of the terminal connection portion extraction surface. In contrast to the fact that a very small space is created for the close contact, the space between the terminal connecting portion lead-out surface and the film-like exterior material is connected to the battery element and connected to the positive terminal connecting portion and the negative terminal connecting portion. This creates a relatively large space.

  On the other hand, the positive electrode terminal connection portion and the negative electrode terminal connection portion are both thought to be easily deformed in any direction by the force applied to the battery stack from the outside because a thin metal foil is used. When the deformation of the positive electrode terminal connecting portion and the negative electrode terminal connecting portion due to the force applied to the battery stack was examined, the positive electrode terminal connecting portion and the negative electrode terminal connecting portion are easily deformed by the force applied in the compression direction. It has been found that it has the feature of being difficult to deform. This is because the electrodes may move in the terminal pull-out direction due to the deformation of the electrode terminal connection, but in the opposite direction, the electrode terminal connection generates a pulling force and moves due to drag. It is considered difficult.

  From these points, in the laminated battery in which the positive electrode lead terminal and the negative electrode lead terminal of the square battery are both taken out from the terminal connection portion extraction surface, the positional displacement of the electrode due to impact tends to occur in the direction toward the terminal connection portion extraction surface. Therefore, paying attention to the fact that the position displacement in the terminal connection portion drawing surface direction is the main one, the prevention of the position displacement in the terminal connection portion drawing surface direction is first performed.

The present invention will be described below with reference to the drawings.
FIG. 1 is a view for explaining an embodiment of the laminated battery of the present invention.
FIG. 1A is a partially cutaway perspective view illustrating a stacked battery of the present invention, and FIG. 1B is a diagram illustrating a cut surface of a battery element taken along line AA ′. FIG. 1C is a diagram for explaining a cut surface of the battery element along the line BB ′.
Note that FIGS. 1B and 1C are different in scale from FIG. 1A in order to clarify the relationship between the laminated members.
The laminated battery 1 is described by taking a lithium ion battery as an example. In the laminated battery 1, the battery element 3 is sealed with a film-shaped exterior material 5. In the battery element 3, the positive electrode 10 and the negative electrode 20 are laminated via a separator 30. In the positive electrode 10, a positive electrode active material layer 13 is formed on a positive electrode current collector 11 made of an aluminum foil or the like. The negative electrode 20 having a larger area than the positive electrode 10 has a negative electrode active material layer 23 formed on a negative electrode current collector 21 made of copper foil or the like.

A region where the positive electrode active material layer is not formed is provided on the positive electrode current collector 11, and the strip-like positive electrode terminal connection portion 15 is formed by a method such as punching out from the region or cutting. Further, the positive terminal connecting portion 15 is connected to the positive lead terminal 17. Similarly, a region where the negative electrode active material layer is not formed is provided on the negative electrode current collector 21, and a band-shaped negative electrode terminal connection portion 25 is formed by a method such as punching out from the region, cutting, and the like. It is connected to the negative electrode lead terminal 27. In addition, you may prepare another component as a positive / negative electrode terminal connection part, and may attach to a collector with welding.
Moreover, the positive electrode extraction terminal 17 and the negative electrode extraction terminal 27 are taken out to the outside by heat-sealing or the like at the sealing portion 7 of the film-shaped outer packaging material 5 respectively, and after the electrolyte solution is injected therein, the pressure is reduced. It is sealed in the state.

The end face of the negative electrode 20 abuts against the abutting portions 33a to 33d formed from the folds 31a to 31d of the separator 30, and the movement toward the negative electrode lead terminal side is restricted. Further, the end face of the positive electrode 10 abuts against the abutting portions 37a to 37c formed by the joining portions 35a to 35c joined by thermal fusion of the opposing surfaces of the adjacent separators 30, and movement in the positive electrode lead terminal direction is restricted.
Furthermore, the positive electrode is moved in the direction opposite to the positive electrode extraction terminal direction by hitting the abutting portions 33e to 33g formed from the folds 31e to 31g of the separator at the end opposite to the positive electrode extraction terminal direction. It is regulated.

In the present invention, the movement is restricted by the abutting portion. As the name implies, even if the flat electrode is about to move in the direction of the abutting portion, there is a portion where the movement is restricted due to the collision of the end face of the flat electrode. The two separators arranged on both sides of the flat electrode are connected outside the electrode region to form a crease, or the movement of the flat electrode is restricted. This means that they are bonded to each other by heat fusion or chemicals, and are joined, stitched, clamped, etc. by adhesive tape, adhesive, thread, rivet, clip or the like.
Further, the abutting portion is not limited to a continuous line shape, and may be a dot shape.

Further, in the embodiment shown in FIG. 1, since the end portions of the separators located outside the abutting portions 33a and 33d of the end portions of the negative electrodes 20a and 20d located in the outermost layer of the battery element are open, the abutting portion The restricting action at 33a and 33d is smaller than that at the other bumps.
However, since the inside of the battery outer packaging material is sealed in a decompressed state, the peripheral edge of the outermost electrode, in this embodiment, the negative electrode peripheral edge, is bent toward the battery inner side by receiving atmospheric pressure via the film-like outer casing. To do. For this reason, the curved portion on the periphery of the negative electrode becomes an obstacle to movement in the direction parallel to the laminated surface, and the negative electrode on the outermost layer is less likely to be displaced than the inner one, and is not held at the abutting portion. However, there is no problem.
Moreover, it can also be set as the structure which does not install a separator in the outer surface of the negative electrode of outermost layer. In such a case, the end portion of the outermost layer negative electrode does not have an abutting portion formed by the separator fold, but even in this case, the outermost layer negative electrode is unlikely to be displaced. There is no problem.

2 is a partially enlarged view of the battery element, FIG. 2 (A) is a partially enlarged view of a portion A in FIG. 1 (B), and FIG. 2 (B) is a view of B in FIG. 1 (C). It is the elements on larger scale of a part.
The negative electrode 20a is restricted from moving toward the negative electrode lead-out terminal side by the abutting portions 33a and 33b formed by the folds 31a and 31b of the separator 30, and the positive electrode 10 has a heat fusion portion 35a on the facing surface of the adjacent separator 30. Movement in the positive electrode lead-out terminal direction is restricted by the abutting portion 37a formed by. Although it is preferable that the end face of each electrode is in contact with the abutting portion, a slight interval may be generated so that the relative position between the positive electrode and the negative electrode does not matter.
Furthermore, since the abutting portion 33e by the separator fold 31e is formed at the end of the positive electrode in the direction opposite to the positive electrode lead terminal direction, movement in the direction opposite to the positive electrode lead terminal direction is restricted. . Further, the cross-sectional shape of the separator shown in FIG. 2A is changed to the cross-sectional shape of the separator shown in FIG.

When the separators of all layers are connected in a zigzag manner as in the above example, the positive electrode and the negative electrode of all layers were formed at the fold of one separator and the joint located inside it. Since the positioning is performed by the contact portion, the movement of the positive electrode and the negative electrode is restricted, and the relative positioning accuracy between the positive electrode and the negative electrode of all layers is improved.
In addition, the separator does not protrude outward from the crease for positioning the negative electrode having a large area, and the negative electrode forms an abutting portion by the folds of the terminal connecting portion lead-out surface and the surface on the opposite side. Except for the terminal connection part, the outer shape can be sized to substantially coincide with the negative electrode end of the abutting part, so that the volume can be reduced compared with the case where the separators are arranged one by one, and the volume energy efficiency is improved. It can be a large battery.

FIG. 3 is a diagram for explaining another embodiment of the stacked battery, and is a diagram for explaining a cut portion of the same part as in FIG. 1 (B).
In the stacked battery shown in FIG. 1 (B), the separator located on the outer surface of the battery element stack is not joined to other members at the end opposite to the lead terminal side of the positive and negative electrodes. .
On the other hand, in the stacked battery shown in FIG. 3A, the separators 30a and 30d located in the outermost layer are joined to the fixing tape 50 at the end opposite to the negative electrode lead terminal side. ing. As a result, the movement of the negative electrode located in the outermost layer of the battery element laminate is more reliably regulated by the closing portion 33a formed by the fold of the separator on the negative electrode lead terminal side located on the outer surface of the laminate.

Further, in the stacked battery shown in FIG. 3B, no separator is disposed on the outer surface of the battery element stack, and the negative electrode lead-out terminal side of the negative electrodes 20a and 20d located in the outermost layer The opposite end is bonded and fixed to a fixing tape 50 that connects both sides.
The movement of the negative electrode of the outermost layer of the laminate is more reliably regulated by the action of the fixing tape.

3C, the outermost negative electrode 20a has a negative electrode active material layer 23 formed only on one surface of the current collector 21. FIG. The outermost current collector 21 is bonded and fixed to a fixing tape that connects both sides.
As described above, the stacked battery shown in FIG. 3C is a slightly stacked battery as compared with the case where the negative electrode on the outer surface is formed with the negative electrode active material layer only on one side, and the negative electrode is formed on both sides. It is necessary to provide a step of forming a negative electrode in which a negative electrode active material layer is formed only on one side and one side, which can reduce the thickness and mass, but any of them can be employed.
Further, in the case where the separator is present in the outermost layer shown in FIG. 3A, the negative electrode of the outermost layer was formed with the negative electrode active material layer only on one side of the current collector, as in FIG. It may be a thing.

  In the above description, the laminated battery is described as an example of a battery in which the area of the negative electrode is larger than that of the opposite positive electrode, such as a lithium ion battery, but the positive electrode is larger than the area of the negative electrode. In that case, it is preferable that the positive electrode is disposed in the outermost layer of the laminate from the viewpoint of preventing the deviation of the laminate sealed by the flexible exterior material.

Next, the manufacturing method of the laminated battery of this invention is demonstrated with reference to drawings.
FIG. 4 is a diagram for explaining one embodiment of a method for producing a laminated battery of the present invention, and will be described by taking a lithium ion battery as an example, as in FIG.
Folds 31a, 31b, 31c and 31e, 31f are formed in a zigzag separator 30W that is equal to the width of the negative electrode or larger than the width of the negative electrode with a length corresponding to the size of the negative electrode, and the folds 31a, 31b, 31c Openings 32a, 32b, and 32c are formed. The length of the opening may be a size obtained by adding the length from the end portion in the width direction of the separator to the fusion portion of the separator formed in the length direction of the positive electrode to the width of the positive electrode terminal connection portion.

Next, the positive electrode 10-2 is positioned between the separators 30-4 and 30-5 at the fold line 31f and arranged at the center in the width direction, and then the separator 30-4 is overlapped with the separator 30-5, Heat fusion is performed at the partial heat fusion part 34 and the positive electrode upper heat fusion part 36, and the positive electrode is positioned and fixed by a separator. Such heat fusion can be performed using a synthetic resin heat fusion means using an electric heater, an ultrasonic wave, a laser, a high frequency, or the like. Moreover, the heat-sealing part is not limited to a continuous linear shape, and may be provided intermittently or in a dotted shape.
In addition, each positive electrode is also positioned in the width direction by both side fused portions 34, and the positive electrode and the negative electrode have high relative positioning accuracy in the horizontal direction.

  These operations are similarly performed on the positive electrode 10-1, and after positioning and fixing all the positive electrodes at predetermined positions of the separator, the negative electrode 20- is formed in the opening 32a between the separators 30-1 and 30-2. 1, the negative electrode terminal connection part 15 a is passed, and the negative electrode 20-1 is positioned at the fold line 31 a of the separator. Similarly, the battery element can be manufactured by sequentially performing operations of disposing the negative electrodes 20-2 and 20-3 between the separators 30-3 and 30-4 and between the separators 30-5 and 30-6.

  Also, one positive electrode is sandwiched between adjacent separators of a fold-shaped separator and heat-sealed. Then, after storing one negative electrode, the positive electrode and the negative electrode are sequentially stored and heat-sealed one by one. Can be manufactured by. Alternatively, after forming the heat-sealed portions 34 on both sides in the width direction of the positive electrode on the left and right sides or one side by heat-sealing on the zigzag folded separator, the positive electrode and the negative electrode are arranged, and one positive electrode upper heat-sealing portion 36 is provided. You may form each one or collectively.

  Then, the obtained battery element is covered with a film-like exterior material, and the electrolyte solution injection port is left and sealed, and after the electrolyte solution is injected from the electrolyte solution injection port, the inside is sealed in a decompressed state. The battery can be manufactured.

FIG. 5 is a diagram for explaining another embodiment of the method for producing a laminated battery of the present invention.
After producing bi-fold separators 30B1 and 30B2 having a length that can cover a single positive electrode in a bag shape with a separator that is equal to or larger than the width of the negative electrode, positive electrode 10-2 is formed on bi-fold separator 30B2. Is positioned at the fold line 31 and arranged so that the positive electrode is located at the center in the width direction of the separator, and is positioned and fixed at the both side heat fusion part 34 and the positive electrode upper heat fusion part 36. The positive electrode upper heat fusion part 36 is a length obtained by adding the width from the separator to the positive electrode terminal connection part and the length from the end in the width direction of the separator to the fusion part of the separator formed in the length direction of the positive electrode. It can be the same or smaller than the reduced one.
These heat-sealed portions can be formed by using a synthetic resin heat-sealing means using an electric heater, an ultrasonic wave, a laser, a high frequency, or the like. Moreover, the heat-sealing part is not limited to a continuous linear shape, and may be provided intermittently or in a dotted shape.

  Next, the negative electrode abutting portion for positioning the negative electrode by placing the negative electrode 20-2 on the separator 30-3 of the bi-fold separator 30B1 coated with the positive electrode, and further stacking the bi-fold separator 30B1 not coated with the positive electrode In a portion corresponding to 38, a joint portion between the separator 30-2 and the separator 30-3 is formed. The joining can be performed by joining means such as heat fusion, adhesive, single-sided adhesive tape, double-sided adhesive tape. In addition, when two separators are stacked and adhesive tape is applied from the outer surface and joined, the outer shape of the battery element excluding the terminal connection portion is set to the negative electrode of the abutting portion in the same manner as when the abutting portion is molded by the bent portion. The size can be approximately the same as the end face.

Further, the positive electrode 10-1 is placed on the bi-fold separator 30B1, and the separators 30-1 and 30-2 are thermally welded to cover the positive electrode 10-1 in the same manner as the bi-fold separator separator 30B2.
The above steps are repeated to produce a battery element. The obtained battery element is covered with a film-like exterior material, and the electrolyte is sealed, leaving the inlet, and after the electrolyte is injected, the inside of the battery is decompressed. After that, the liquid inlet can be sealed to obtain a laminated battery.

In the above description, the bag-shaped separator that accommodates the positive electrode is one in which one separator is folded in two to form both-side fused portions, but the two separators that can cover the positive electrode are Except for the electrode terminal connection portion, it is also possible to use a bag having three sides joined continuously or intermittently.
Further, after forming all the negative electrode abutting portions 38 and all the both side heat fusion portions 34 on both the left and right sides or one side, after accommodating the positive electrode and the negative electrode, the positive electrode upper heat fusion portions 36 are one by one or collectively. In this method, the order of forming the negative electrode abutting portion 38 and the positive electrode upper heat fusion portion 36 may be reversed.

  Moreover, instead of the method of joining the separators in close contact with each other, the joining of the heat fusion parts between the adjacent separators is performed after the laminate is formed without forming the heat fusion parts, and then the positive electrode terminal connection part, the negative electrode At least one of the terminal connection part, the positive electrode in the vicinity of the positive electrode terminal connection part, and the negative electrode in the vicinity of the negative electrode terminal connection part, from the upper and lower surface outside of the laminated electrode terminal connection part or the upper and lower surface outside of the battery element, While heating by means of ultrasonic application, etc., the part corresponding to the part to be heat-sealed is pressed from outside the upper and lower surfaces of the battery element, or the part corresponding to the part to be heat-sealed is outside the upper and lower face of the battery element By directly heating or heating and pressing from above, all the layers can be collectively formed into the heat fusion part.

FIG. 6 is a diagram for explaining another embodiment of the method for producing a laminated battery of the present invention.
As shown in FIG. 6A, negative electrode-coated separators 30C1 and 30C2 that cover both sides of a single negative electrode that is equal to or larger than the negative electrode width are prepared. Form. The length of the opening may be the width of the negative terminal connecting portion.
The separator 30-2 of the negative electrode-coated separator 30C1 and the separator 30-3 of the negative electrode-coated separator 30C2 are in close contact with each other, and the both sides are heat-fused at the both-side heat fusion part 34 and the positive electrode upper heat fusion part 36. To wear.

Next, as shown in FIG. 6B, the negative electrode 20-1 is arranged in the negative electrode-coated separator 30C1, and the positive electrode is arranged in the space formed by heat fusion between the two negative electrode-coated separators 30C1 and 30C2. To do. Similarly, the separator 30-1 is formed with a heat-sealing portion that positions another positive electrode by closely contacting another negative electrode-coated separator.
By repeating these operations until the number of positive and negative electrodes reaches a predetermined number, the joining of the negative electrode-coated separator and the placement of the positive and negative electrodes are repeated to produce a battery element. Covering is performed to leave the injection port of the electrolytic solution, and after pouring the electrolytic solution, the inside of the battery is decompressed, and then the injection port is sealed to obtain a stacked battery.

  Further, after all the portions to be joined of the separator are joined by thermal fusion to form an integral separator, the positive electrode and the negative electrode may be inserted into predetermined portions of the separator. In this case, it is possible to separately perform the joining by the thermal fusion of the separator and the operation of inserting the positive electrode or the negative electrode into a predetermined place, so that the degree of freedom in the manufacturing process is increased, and a plurality of positive electrodes or negative electrodes are simultaneously attached. It can also be inserted.

FIG. 7 is a diagram for explaining another embodiment of the method for manufacturing a laminated battery of the present invention.
The zigzag separator shown in FIG. 4 is provided with an opening through which the negative electrode terminal connection portion passes in the crease, and the positive electrode is provided with a blocking portion for positioning by forming a heat fusion portion in the width direction and the height direction. On the other hand, the zigzag folded separator described in FIG. 7 is positioned by a closing portion composed of a heat-sealing portion extending in a direction perpendicular to the fold of the separator.
In other words, the zigzag folded separator 30 is a heat-sealed portion extending in a direction perpendicular to the fold line 31a for positioning in the direction of the electrode terminal connecting portion of the negative electrode after the separator 30-1 and the separator 30-2 are adjacently formed by the fold line 31a. 36a is formed, and then the adjacent separator 30-2 and separator 30-3 are formed in a direction perpendicular to the fold line 31b that forms the fold line 31b and positions the positive electrode together with the fold line 31b. A battery element is manufactured by arranging the positive electrodes 10-1 and 10-2 and the negative electrodes 20-1 and 20-2 at predetermined positions of a zigzag separator by performing an operation of forming the extended heat-sealing portion 36b. It is.

In this method, the electrode terminal lead-out direction can be adjusted to different positions on the positive electrode side and the negative electrode side by adjusting the positions of the heat fusion portions 36a and 36b. Are positioned by folds.
Therefore, not only the electrode extraction direction but also the movement in the perpendicular direction is positioned by the fold and the movement is restricted.
In order to increase the area of the negative electrode facing the positive electrode as in a lithium ion battery, the length in the direction perpendicular to the electrode terminal lead-out direction of the separator is the length of the positive electrode, the length of the negative electrode and the positive electrode It is preferable to set the length to which one half of the difference from the length is added.
In this case, the negative electrode has a length that is one-half of the difference from the positive electrode that protrudes from the end face of the separator. However, since contact with the positive electrode does not occur, battery characteristics are not adversely affected. .

Also in this case, as in the example of FIG. 6, all the parts to be joined of the separator are joined by thermal fusion to form an integrated separator, and then the positive electrode and the negative electrode are inserted into predetermined parts of the separator. Good. In this case, it is possible to separately perform the joining by the thermal fusion of the separator and the operation of inserting the positive electrode or the negative electrode into a predetermined place, so that the degree of freedom in the manufacturing process is increased, and a plurality of positive electrodes or negative electrodes are simultaneously attached. It can also be inserted.
The battery element produced as described above can be sealed with a film-like exterior material in the same manner as in other embodiments to form a laminated battery.

  The laminated battery of the present invention can accurately position both the positive electrode and the negative electrode by forming a contact portion in which movement of the electrode end face is restricted by a crease or heat fusion or the like in the separator of the laminated battery. It is possible to easily position the battery at the time of manufacturing the battery, and even when excessive impact or vibration is applied to the battery, the relative position between the positive electrode and the negative electrode shifts and the characteristics of the battery deteriorate. Therefore, a battery with good characteristics can be provided.

FIG. 1 is a view for explaining an embodiment of the laminated battery of the present invention. FIG. 2 is a partially enlarged view of the battery element. FIG. 3 is a diagram illustrating another embodiment of the multilayer battery of the present invention. FIG. 4 is a diagram for explaining one embodiment of a method for producing a laminated battery of the present invention. FIG. 5 is a diagram for explaining another embodiment of the method for producing a laminated battery of the present invention. FIG. 6 is a diagram for explaining another embodiment of the method for producing a laminated battery of the present invention. FIG. 7 is a diagram for explaining another embodiment of the method for manufacturing a laminated battery of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Stack type battery, 3 ... Battery element, 5 ... Film-like exterior material 10, 10-1, 10-2 ... Positive electrode, 20, 20-1, 20-2, 20a, 20d ... Negative electrode, 11 ... Positive electrode collection Electrode, 13 ... Positive electrode active material layer, 21 ... Negative electrode current collector, 23 ... Negative electrode active material layer, 15 ... Positive electrode terminal connection part, 17 ... Positive electrode extraction terminal, 25 ... Negative electrode terminal connection part, 27 ... Negative electrode extraction terminal, 7 ... Sealing part, 30, 30-1 thru | or 30-6, 30a, 30d ... Separator, 30B1, 30B2 ... Bifold separator, 30C1, 30C ... Negative electrode coating | coated separator, 230W ... Spiral folding separator, 31a-31d, 31e-31g ... Folds, 33a to 33d, 33e to 33g ... Abutting portion, 34 ... Heat fusion portion on both sides, 35a to 35c ... Heat fusion portion, 36 ... Positive upper heat fusion portion, 37a-37c ... Abutting portion, 50 Fixing tape

Claims (10)

  A plate-like positive electrode terminal connecting portion and a plate having a rectangular battery element in which a plate-like positive electrode, a separator, and a plate-like negative electrode are laminated, and one surface of the battery element is provided on each of the positive electrode and the negative electrode The negative electrode terminal connection portion is a terminal connection portion extraction surface that is drawn out together, and the projection surfaces obtained by projecting each of the positive electrode terminal connection portion and the negative electrode terminal connection portion perpendicularly to the surfaces extending the positive electrode and the negative electrode do not cross each other. The positive electrode and the negative electrode have different areas of surfaces facing each other, and all projections obtained by projecting the electrodes having the smaller area onto the surfaces facing the electrodes having the larger area are located on the electrode surface on the larger side. The separator is provided with an abutting portion that restricts the movement of the positive electrode and the negative electrode by abutting the positive electrode end surface and the negative electrode end surface, and the abutting portion is provided on each electrode surface. The separators are formed by folds or joints between adjacent separators, and all separators stacked on the electrode surface are joined by the folds or joints. Stacked battery.   The electrode having a smaller area is wrapped with a bag-shaped separator, and the abutting portion is formed by a joint portion of adjacent bag-shaped separators, and the electrode having a smaller area is positioned at the abutting portion. The stacked battery according to claim 1.   2. The stacked battery according to claim 1, wherein the abutting portion for restricting the movement of the electrode having a large area is a fold of the separator, and the abutting portion for restricting the movement of the electrode having a small area is a joint portion of the separator. .   4. The stacked battery according to claim 3, wherein the electrode having a small area is surrounded by a joining portion of separators on two sides adjacent to a side located on the terminal connecting portion lead-out surface.   The separator is formed of a zigzag fold-like member in which a zigzag fold portion is positioned on a terminal connection portion drawing surface, and has an opening through which the positive electrode terminal connection portion or the negative electrode terminal connection portion passes. 3. The laminated battery according to 3.   The separator is made of a zigzag-like member in which a zigzag fold portion is located on a surface other than the terminal connection portion lead-out surface, and the electrode is positioned by the abutting portion formed by joining formed at a position perpendicular to the fold. The multilayer battery according to claim 3, wherein:   The laminated battery according to any one of claims 1 to 6, wherein the joining portion of the separator is continuous linear or intermittent by any one of welding, an adhesive, and an adhesive tape.   The separator or electrode located in the outermost layer is joined to a fixing tape disposed on the side opposite to the terminal connecting portion lead-out surface of the battery element. Stacked battery.   A plate-like positive electrode provided with a plate-like positive electrode terminal connecting portion and a plate-like negative electrode provided with a plate-like negative electrode terminal connecting portion are arranged such that the positive electrode terminal connecting portion and the negative electrode terminal connecting portion face the same direction. The positive electrode and the negative electrode were laminated with a separator disposed on the electrode surface so that the surfaces of the positive electrode terminal connection portion and the negative electrode terminal connection portion projected perpendicularly to the surfaces of the positive electrode and the negative electrode extended did not cross each other. Later, by heating at least one of the positive electrode terminal connection part and the negative electrode terminal connection part and thermally fusing the adjacent separator, an abutting part that restricts movement of at least one of the positive electrode and the negative electrode is formed. A method for manufacturing a laminated battery, which is characterized.   After the electrode having the smaller electrode area is accommodated in the bag-shaped separator and the plate-shaped electrode terminal connection portion bonded to the current collector is taken out, at least a part of the opening of the bag-shaped separator other than the portion is joined, The electrode end face with a large area is regulated by heating the terminal connection part of the electrode with a small area or the current collector side of the electrode, and heat-sealing the separator. A method of manufacturing a stacked battery, comprising forming an abutting portion.

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