JP6859059B2 - Lithium-ion secondary battery and its manufacturing method - Google Patents

Description

The present invention relates to a lithium ion secondary battery and a method for manufacturing the same.

Conventionally, lithium-ion secondary batteries have the characteristics of higher energy density and electromotive force than lead-acid batteries and nickel-metal hydride batteries, so they are power supplies for various portable devices and notebook computers that are required to be smaller and lighter. Widely used as. A lithium ion secondary battery usually has a positive electrode plate in which a positive electrode active material is applied to a positive electrode current collector and a negative electrode plate in which a negative electrode active material is applied to a negative electrode current collector, and a separator and an electrolyte are provided between them. It is manufactured by interposing and laminating, and sealing the laminated body in which the positive electrode plate, the separator and the negative electrode plate are laminated inside the exterior body (see, for example, Patent Document 1). At this time, as the electrolyte, a gel-like electrolyte is used in addition to a liquid or solid electrolyte.

Then, as shown in FIG. 9, in the lithium ion secondary battery 100, in order to extract electricity from the electrodes of the positive electrode and the negative electrode, the active material coating portion 102 extends at one end in the length direction extending in one direction of the current collector 101. The active material uncoated portion 103 to which the active material is not applied is formed as described above, and the terminal tab 104 is welded to the active material uncoated portion 103 so as to protrude from the current collector 101 ( For example, see Patent Document 2).

Japanese Unexamined Patent Publication No. 2015-88394 International Publication No. 2012/127563

However, the lithium ion secondary battery having a laminated structure as shown in Patent Document 1 has the following problems.
That is, in the lithium secondary battery shown in FIG. 9, the active material coating portion is a portion that contributes to the capacity of the battery when it is used as a secondary battery, but the active material secures an area where the terminal tabs can be welded. By providing the uncoated portion, the effective range of the electrode becomes smaller than the cell size. That is, since the ratio of the active material coated portion is reduced only in the region where the active material is not coated, the volumetric energy density is reduced, and the effective range as an electrode is narrowed, there is room for improvement in this respect.

Lithium-ion secondary batteries are often installed in a limited space, and the size (area) of the entire battery is limited. Therefore, it is possible to increase the volumetric energy density by increasing the area of the active material coated portion and narrowing the area of the active material uncoated portion, but it becomes difficult to attach the terminal tab and the welded portion. There is a problem that the fixing strength is lowered, the tabs for terminals may be displaced or easily detached, and the reliability of conduction such as an increase in internal resistance in the battery is lowered.

The present invention has been made in view of the above-mentioned problems, and provides a lithium ion secondary battery and a method for manufacturing the same, which can improve the battery performance by increasing the effective range of the electrode active material layer. With the goal.

In order to achieve the above object, the lithium ion secondary battery according to the present invention has a positive electrode and a negative electrode formed by applying an active material to the surface of the current collector, leaving an uncoated portion of the active material to form an electrode active material layer. In a lithium ion secondary battery provided with an electrode laminate in which and are alternately laminated via an insulator, the electrode composed of the positive electrode and the negative electrode has the active material uncoated portion of the current collector. It is located on one end side in the length direction extending in one direction, and is provided in a part of the width direction orthogonal to the length direction in a plan view, and the active material uncoated portion forms a terminal tab. There is.

Further, in the lithium ion secondary battery according to the present invention, a plurality of the above-mentioned lithium ion secondary batteries are connected, and the notch recess of the first electrode of either the positive electrode or the negative electrode is the first. Of the positive electrode and the negative electrode laminated with respect to the electrodes, the terminal tabs of the first electrode formed in a region overlapping the terminal tabs of the other second electrode and overlapping in the stacking direction, and the second electrode The terminal tabs of the above are connected to each other.

Further, in the method for manufacturing a lithium ion secondary battery according to the present invention, a positive electrode and a negative electrode formed by applying an active material to the surface of the current collector, leaving an uncoated portion of the active material, and forming an electrode active material layer. A method for manufacturing a lithium ion secondary battery including electrode laminates that are alternately laminated via an insulator, at a position on one end side in the length direction extending in one direction of the current collector and on a flat surface. The step of applying the active material to the surface of the current collector with the uncoated portion of the active material left in the central portion in the width direction perpendicular to the length direction visually, and the other of the length direction of the current collector. On the end side, a step of forming a notch recess in the central portion in the width direction, and in the current collector, the active material uncoated portion and the active material uncoated portion located on both sides in the width direction. A step of forming a cut portion along a boundary line between the material coated portion and forming the uncoated portion of the active material cut out by the cut portion as a terminal tab, and the positive electrode and the negative electrode overlapping in the stacking direction. A step of connecting the terminal tabs of one of the first electrodes and the terminal tabs of the other second electrode of the positive electrode and the negative electrode laminated on the first electrode. The notch recess of the first electrode is formed in a region overlapping the terminal tab of the second electrode.

In the present invention, the electrode active material layers formed on the positive electrode and the negative electrode can be provided in the range up to both ends of the length dimension of the lithium ion secondary battery in the length direction. The volumetric energy density is higher and the effective range of the electrode active material layer is increased as compared with the configuration in which the active material uncoated portion for providing the terminal tabs is provided along both end edges in the length direction of the secondary battery. And the battery efficiency can be improved. Further, since the active material uncoated portion of the electrode is provided in a part in the width direction and the active material uncoated portion is formed as a terminal tab, the electrode active material has the function of the terminal tab as before. Increasing the effective range of the layers can be achieved in a well-balanced manner.

Further, in the lithium ion secondary battery according to the present invention, the active material uncoated portions may be located at both ends in the length direction.

Further, in the lithium ion secondary battery according to the present invention, the current collector is between the active material uncoated portion and the active material coated portion located on both sides of the active material uncoated portion in the width direction. It is preferable that a cut portion is formed along the boundary line of the above, and the uncoated portion of the active material cut out by the cut portion forms a tab for terminals.

In this case, since the cut portion is formed along the boundary line between the active material uncoated portion and the active material coated portion located on both sides in the width direction of the active material uncoated portion, the cut portion is collected. The terminal tabs of the active material uncoated portion formed only by the electric body are separated from the active material coated portions on both sides in the width direction. Therefore, the terminal tabs can be curved with the portion connected to the active material coating portion in the length direction as the base end, and the terminal tabs can be reliably connected to each other by welding or the like.

Further, it is preferable that the lithium ion secondary battery according to the present invention is connected to the terminal tab in a state where the extension tab is further overlapped.

In this case, an extension tab can be provided via a terminal tab located in the active material uncoated portion of the current collector.

Further, in the lithium ion secondary battery according to the present invention, it is preferable that the active material uncoated portion is provided at the central portion in the width direction in a plan view.

In this case, the active material coated portion is formed on both sides in the width direction of the active material uncoated portion, and the terminal tab can be reliably held by being sandwiched by the active material coated portion.

Further, in the lithium ion secondary battery according to the present invention, the active material uncoated portion is located on one end side in the length direction extending in one direction of the current collector, and is located in the length direction of the current collector. It is preferable that a notch recess is formed in a part of the width direction on the other end side.

In this case, the electrode has a notch recess formed in the central portion in the width direction on the other end side opposite to the one end side on which the terminal tab is formed in the length direction, so that the positive electrode and the negative electrode are formed. In the configuration in which the tabs are stacked on each other, the current collector is not arranged in the stacking direction of the tabs for each terminal, and the tabs for the positive electrode terminals and the tabs for the terminals on the negative electrode are stacked and connected in the stacking direction. Can be done.

Further, in the lithium ion secondary battery according to the present invention, the notch recess may be formed in the central portion in the width direction.

In this case, the terminal tabs interposed in the notch recesses form a space sandwiched by the current collectors forming the active material coating portions located on both sides of the notch recesses in the width direction. Can be stored compactly.

Further, in the lithium ion secondary battery according to the present invention, the active material uncoated portion and the notch recess notched from the current collector are provided on one end side of the current collector in the length direction. It may be formed at intervals in the width direction.

Further, in the lithium ion secondary battery according to the present invention, the positive electrode and the negative electrode formed by applying the active material to the surface of the current collector, leaving the uncoated portion of the active material as an insulator. A lithium ion secondary battery including an electrode laminate formed by alternately laminating the electrodes, and one of the electrodes composed of the positive electrode and the negative electrode is in the length direction extending in one direction of the current collector. The active material uncoated portion is provided in a part of the width direction which is located on one end side and is orthogonal to the length direction in a plan view, and the other electrode is attached to one end edge in the width direction adjacent to the one end side. It is characterized in that the active material uncoated portion is provided in a part of the length direction in a plan view, and the active material uncoated portion forms a tab for a terminal.

In the present invention, the electrode active material layers formed on the positive electrode and the negative electrode can be provided in the range up to both ends of the length dimension of the lithium ion secondary battery in the length direction. The volumetric energy density is higher and the effective range of the electrode active material layer is increased as compared with the configuration in which the active material uncoated portion for providing the terminal tabs is provided along both end edges in the length direction of the secondary battery. And the battery efficiency can be improved. Further, since the active material uncoated portion of the electrode is provided on a part of one end side in the length direction or a part of one end edge in the width direction, and the active material uncoated part is formed as a tab for terminals, conventionally. It is possible to achieve a well-balanced increase in the effective range of the electrode active material layer while providing the function of the terminal tab as it is.

Further, in the lithium ion secondary battery according to the present invention, one of the electrodes has a notched recess formed by cutting out the current collector at one end edge in the width direction adjacent to the one end side of the current collector. The other electrode is preferably formed with a notch recess in which the current collector is cut out on one end side in the length direction extending in one direction of the current collector.

In this case, the current collector is not arranged in the stacking direction of the tabs for each terminal, and the tabs for the terminals of the positive electrode and the tabs for the terminals of the negative electrode can be stacked and connected in the stacking direction.

Further, in the lithium ion secondary battery according to the present invention, the length dimension of the electrode active material layer formed on the electrodes to be laminated in the length direction is the same for all the electrodes constituting the electrode laminate. Is preferable.

In this case, the electrode active material layer of each electrode can be formed in the range of the total length in the length direction of the lithium ion secondary battery, and the effective range of the electrode active material layer can be effectively increased.

According to the lithium ion secondary battery of the present invention and the method for producing the same, the battery performance can be improved by increasing the effective range of the electrode active material layer.

It is a main part perspective view which shows the structure of one end side which laminated the positive electrode plate and the negative electrode plate in the lithium ion secondary battery by embodiment of this invention. It is a top view of the negative electrode plate which comprises the lithium ion secondary battery shown in FIG. It is a top view of the positive electrode plate which comprises the lithium ion secondary battery shown in FIG. It is a main part perspective view which shows the structure of one end side which laminated the positive electrode plate and the negative electrode plate by 1st modification, and is the figure corresponding to FIG. It is a vertical cross-sectional view which shows typically the structure of the conventional lithium ion secondary battery. It is a main part perspective view which shows the structure of one end side which laminated the positive electrode plate and the negative electrode plate by the 2nd modification, and is the figure corresponding to FIG. It is a top view of the electrode which comprises the lithium ion secondary battery by the 2nd modification. It is a top view of the electrode which constitutes the lithium ion secondary battery by the 3rd modification. It is a main part perspective view which shows the structure of one end side which laminated the positive electrode plate and the negative electrode plate in the conventional lithium ion secondary battery.

Hereinafter, a lithium ion secondary battery according to an embodiment of the present invention and a method for manufacturing the same will be described with reference to the drawings.

As shown in FIG. 1, in the lithium ion secondary battery 1 according to the present embodiment, the positive electrode plate 2 (positive electrode) and the negative electrode plate 3 (negative electrode), which are electrode plates, are formed of a semi-solid or solid electrolyte layer and the figure. A schematic configuration including an electrode laminate 10 in which terminal tabs 4 and 5 are formed at the respective ends of the positive electrode plate 2 and the negative electrode plate 3 by interposing and laminating the separator 6 (insulator) shown in 5. Has been done.
The electrode laminate 10 is housed and sealed inside a sheet-shaped exterior body (not shown).

In the electrode laminate 10, a gel-like electrolyte layer and a separator 6 (see FIG. 5) are formed by applying a gel-like electrolyte solution on the surface of at least one of the positive electrode plate 2 and the negative electrode plate 3. It becomes.

In the lithium ion secondary battery 1, a plurality of electrode laminates 10 are packaged by an exterior body (not shown) made of, for example, an aluminum material or a polymer film, and terminal tabs formed on the plurality of positive electrode plates 2. The outer peripheral portion of the exterior body is sealed in a state where the terminal tabs 5, 5, ... Formed on the four, four, ..., And the plurality of negative electrode plates 3 are connected to each other and protrude to the outside. ing.

As shown in FIG. 3, the positive electrode plate 2 is, for example, in a positive electrode current collector 21 made of an aluminum foil formed in a rectangular shape in a plan view, one end side in the length direction X (length direction extending in one direction). A portion where the active material uncoated portion 2A is formed in the central portion in the width direction Y orthogonal to the length direction X in a plan view (on the right side of the paper surface in FIG. 3), and the active material uncoated portion 2A is excluded. The positive electrode active material layer 22 (electrode active material layer) formed by applying the active material to the surface is formed. The active material uncoated portion 2A constitutes a terminal tab 4 of the positive electrode plate 2 serving as a bonding allowance.
A conductive metal foil is used for the positive electrode current collector 21, and for example, aluminum, stainless steel, nickel, titanium, alloys thereof, or the like is adopted.

Further, on the other end side (left side of the paper surface in FIG. 3) of the positive electrode current collector 21 in the length direction X, a positive electrode notch recess 23 is formed in the central portion in the width direction Y. The positive electrode notch recess 23 is formed in a region overlapping the terminal tab 5 (see FIG. 5) of the negative electrode plate 3 laminated with respect to the positive electrode plate 2.
The positive electrode current collector 21 is a positive electrode along a boundary line between the active material uncoated portion 2A and the active material coated portions 22a and 22b located on both sides in the width direction Y of the active material uncoated portion 2A. The cut portion 24 may be formed. The active material uncoated portion 2A cut out by the positive electrode cutting portion 24 constitutes the terminal tab 4 of the positive electrode plate 2 described above.

The positive electrode active material layer 22 is formed by applying, for example, a positive electrode slurry obtained by dispersing a positive electrode active material, a conductive auxiliary agent, and a binder serving as a binder in a solvent to the positive electrode current collector 21. For example, it is applied to both surfaces in a region between both ends of the positive electrode current collector 21 in the width direction Y.
The positive electrode active material is not particularly limited, and for example, a lithium metal acid compound represented by the general formula LiMxOy (where M is a metal and x and y are composition ratios of metal M and oxygen O) is used. be able to. Specifically, as the lithium metal acid compound, lithium cobalt oxide, lithium nickel oxide, lithium manganate, a ternary system (nickel, manganese, cobalt system) of these, lithium iron phosphate, and the like are used.
As the conductive auxiliary agent in the positive electrode active material layer 22, for example, acetylene black, carbon nanofibers and the like are used, and as the binder, for example, polyvinylidene fluoride and the like are used.

As shown in FIG. 2, the negative electrode plate 3 is, like the positive electrode plate 2, one end portion in the length direction X of, for example, a negative electrode current collector 31 made of copper (Cu) formed in a rectangular shape in a plan view. The active material uncoated portion 3A is formed in the central portion of the width direction Y which is located on one end side (left side of the paper surface in FIG. 2) and is orthogonal to the length direction X in a plan view. The negative electrode active material layer 32 (electrode active material layer) formed by applying the active material to the removed portion is formed. The active material uncoated portion 3A constitutes a terminal tab 5 of the negative electrode plate 3 serving as a bonding allowance.
A conductive metal foil is used for the negative electrode current collector 31, and for example, copper, stainless steel, nickel, titanium or an alloy thereof is adopted.

Further, on the other end side of the negative electrode current collector 31 in the length direction X (on the right side of the paper surface in FIG. 2), a negative electrode notch recess 33 is formed in the central portion in the width direction Y. The negative electrode notch recess 33 is formed in a region overlapping the terminal tab 4 (see FIG. 5) of the positive electrode plate 2 laminated with respect to the negative electrode plate 3.
Similar to the positive electrode current collector 21, the negative electrode current collector 31 includes the active material uncoated portion 3A and the active material coated portions 33a and 33b located on both sides in the width direction Y of the active material uncoated portion 3A. The negative electrode cutting portion 34 may be formed along the boundary line between the two (see FIG. 4). The active material uncoated portion 3A cut out by the negative electrode cutting portion 34 constitutes the terminal tab 5 of the negative electrode plate 3 described above.

In the negative electrode active material layer 32, for example, a negative electrode slurry obtained by dispersing a negative electrode active material, a binder serving as a binder, and a conductive auxiliary agent added as needed in a solvent is applied to the negative electrode current collector 31. For example, it is applied to both surfaces in a region between both ends of the negative electrode current collector 31 in the width direction Y.
The negative electrode active material is not particularly limited, and for example, a carbon material made of carbon powder or graphite powder or a metal oxide such as lithium titanate can be used, but a lithium ion secondary battery 1 having a higher capacity can be used. From the viewpoint of realization, it is preferable to use a silicon-based active material.
As the binder, for example, polyvinylidene fluoride or the like can be used, and as the conductive auxiliary agent, for example, acetylene black, carbon nanotubes or the like can be used.

Then, as shown in FIG. 5, the lithium ion secondary battery 1 has terminal tabs 4, 4, ... Of the plurality of positive electrode plates 2 overlapping in the stacking direction, and terminal tabs 5, 5 of the plurality of negative electrode plates 3. , ... They are connected to each other by crimping or adhering, respectively. At this time, the terminal tabs 4, 4, ... Of the positive electrode plate 2 and the terminal tabs 5, 5, ... Of the negative electrode plate 3 are integrally provided by bending as appropriate.

The electrolyte layer is formed, for example, by applying a liquid or semi-solid (gel-like) electrolyte on the plate surface of the strip-shaped negative electrode plate 3, or is formed by laminating a solid electrolyte. In the illustrated example, the electrolyte layer is shown at the same position as the separator.
The electrolyte layer may be provided on either the surface of the strip-shaped positive electrode plate 2 or the negative electrode plate 3, but may be provided on both plate surfaces of the positive electrode plate 2 and the negative electrode plate 3, for example.
The electrolyte layer may have a structure having a separator function. For example, a configuration in which the voids of the insulating porous body are impregnated with the electrolyte can be exemplified.
In addition to the electrolyte layer, the electrolyte is preferably present in the voids of the electrode active material layers of the positive electrode plate 2 and the negative electrode plate 3.

When the electrolyte layer is formed from a semi-fixed gel-like electrolyte, it is composed of, for example, a polymer matrix and a non-aqueous electrolyte solution (that is, a non-aqueous solvent and an electrolyte salt), and is gelled to cause adhesiveness on the surface. An electrolyte layer can be formed by applying the material onto the electrode plate. Alternatively, as will be described later, as the gel-like electrolyte, it is also possible to use an electrolyte which is composed of a polymer matrix and a non-aqueous solvent and becomes a solid electrolyte by solidifying after coating.
In the present embodiment, either a semi-fixed or fixed electrolyte may be used, but when a semi-fixed gel-like electrolyte is used, it adheres when applied to the positive electrode plate 2 or the negative electrode plate 3. Those having a property are used, and it is preferable to use one that forms a self-supporting film that does not separate from the plate surface of the positive electrode plate 2 or the negative electrode plate 3.

Examples of the polymer matrix include polyvinylidene fluoride (PVDF), hexafluoropropylene copolymer (PVDF-HFP), polyacrylonitrile, alkylene ethers such as polyethylene oxide and polypropylene oxide, polyester, polyamine, polyphosphazene, and the like. Polysiloxane or the like can be used.

Examples of the non-aqueous solvent include lactone compounds such as γ-butyrolactone; carbonate compounds such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; and carboxylic acids such as methyl formate, methyl acetate and methyl propionate. Ester compounds; ether compounds such as tetrahydrofuran and dimethoxyethane; ether compounds such as tetrahydrofuran and dimethoxyethane; nitrile compounds such as acetonitrile; sulfone compounds such as sulfolane, amide compounds such as dimethylformamide, etc., alone or in admixture of two or more. Can be used.

It is also possible to solidify the gel-like electrolyte after coating to form it as a solid electrolyte layer. In this case, the gel-like electrolyte is, for example, a nitrile compound such as acetonitrile; an ether compound such as tetrahydrofuran: A compound prepared by using an amide compound such as dimethylformamide alone or by mixing two or more kinds can be used.
The electrolyte salt is not particularly limited, but lithium salts such as lithium hexafluorophosphate, lithium perchlorate, and lithium tetrafluoroborate can be used.

The material of the separator is not particularly limited, but for example, an olefin-based polyethylene, polypropylene, or a cellulosic-based material can be used. Then, a non-woven fabric or the like made of these materials can be adopted as the separator.

The exterior body is composed of a base material made of a sheet-like metal material and an adhesive layer provided on at least a part of the surface side of the base material. As the base material of the exterior body, for example, a known material conventionally used in this field such as a flexible laminated resin film, an aluminum material, and a stainless steel material can be used.

Next, the method for manufacturing the lithium ion secondary battery 1 described above will be described in detail with reference to the drawings. Here, an example in which the cut portions 24 and 34 are provided on the positive electrode plate 2 and the negative electrode plate 3 shown in FIG. 4 described above will be described.
As shown in FIGS. 1 to 3, in the method of manufacturing the lithium ion secondary battery 1, first, in the positive electrode current collector 21 and the negative electrode current collector 31, the positions on one end side of the length direction X extending in one direction, respectively. The active material is applied to the surfaces of the positive electrode current collector 21 and the negative electrode current collector 31 with the active material uncoated portions 2A and 3A left in the central portion in the width direction Y in a plan view. That is, the active material uncoated portions 2A and 3A remain as the positive electrode current collector 21 and the negative electrode current collector 31, respectively.
Further, on the other end side of the current collector 21 in the length direction X, notch recesses 23 and 33 are formed in the central portion in the width direction Y.

Next, as shown in FIG. 3, in the positive electrode current collector 21, between the active material uncoated portion 2A and the active material coated portions 22a and 22b located on both sides in the width direction Y of the active material uncoated portion 2A. The positive electrode cutting portion 24 is formed along the boundary line of the above, and the active material uncoated portion 2A cut out by the positive electrode cutting portion 24 is formed as the terminal tab 4. Similarly, in the negative electrode current collector 31, along the boundary line between the active material uncoated portion 3A and the active material coated portions 32a and 32b located on both sides in the width direction Y of the active material uncoated portion 3A. The negative electrode cutting portion 34 is formed, and the active material uncoated portion 3A cut out by the negative electrode cutting portion 34 is formed as the terminal tab 5.

Next, as shown in FIG. 5, the electrode laminate 10 is formed. At this time, for example, a method in which the positive electrode plate 2, the negative electrode plate 3, and the separator 6 formed in a strip shape are cut in cell units in advance, and then these are laminated in the order of the negative electrode plate 3, the separator 6, and the positive electrode plate 2. can do. Alternatively, a method can be adopted in which the strip-shaped positive electrode plate 2, the negative electrode plate 3, and the separator 6 are continuously fed out from a roll around which they are wound and sequentially laminated, and then the laminated body is divided into cell units.
Further, as a method of forming the semi-fixed or fixed electrolyte layer, for example, it is formed in advance on at least one plate surface of the positive electrode plate 2 or the negative electrode plate 3 or on both surfaces of the separator 6 before laminating. The method can be adopted.

After that, as shown in FIG. 1, the terminal tabs 4, 4, ... Of the positive electrode plates 2 overlapping in the stacking direction are connected to each other, and the terminal tabs 5, 5, ... Of the negative electrode plate 3 are connected to each other.

The electrode laminate 10 provided in the lithium ion secondary battery 1 has a configuration in which each of the electrode plates 2, 3 and the separator 6 and the gel-like electrolyte layer are provided one by one, but the present invention is limited to this. It's not something. For example, although detailed illustration is omitted, the electrode laminate may be configured by further stacking a plurality of membrane electrode assemblies having the above configuration. In such a case, a plurality of electrode laminates divided into cell units may be used. It may be laminated, or the strip-shaped electrode laminate may be wound so that the positive electrode plate is located inside. At this time, for example, it is possible to laminate a positive electrode plate with 9 layers and a negative electrode plate with 10 layers to form a multi-layer electrode laminate in which both outermost layers are negative electrode plates. The present invention can be applied without any limitation even in the case of manufacturing a lithium ion secondary battery having a body.
In forming the multilayer electrode laminate, the positive electrode active material layer should not be a plate surface facing outward of the lowermost layer of the multilayer electrode laminate or a plate surface facing outward of the uppermost layer. It is preferable that the structure is formed so that the generation of dendrite can be prevented.

Then, in the step of forming the electrode laminate 10, the terminal tabs 4 and 5 are joined to the active material uncoated portions 2A and 3A which are the ends of the positive electrode plate 2 and the negative electrode plate 3 by joining means such as welding. To do.
Specifically, welding electrodes (not shown) are arranged above and below the electrode laminate 10, and the positive electrode plate 2 and the terminal tab 4 are placed below the negative electrode plate 3, the separator 6, and the electrolyte layer from above and below. It can be held by a welding electrode and welded. Similarly, the negative electrode plate 3 and the terminal tab 5 can be sandwiched by welding electrodes from above and below with the separator 6, the gel-like electrolyte layer, and the positive electrode plate 2 interposed therebetween to perform welding. ..

Next, the operation of the above-mentioned lithium ion secondary battery and its manufacturing method will be described in detail with reference to the drawings.
As shown in FIGS. 1 to 3 and 5, in the present embodiment, the active material layers 22 and 32 formed on the positive electrode plate 2 and the negative electrode plate 3 are the lithium ion secondary battery 1 in the length direction X. Since it is provided in the range up to both ends of the length dimension, it is compared with the conventional configuration in which the active material uncoated portion is provided for providing the terminal tabs along the both end edges in the length direction of the lithium ion secondary battery. Therefore, the volumetric energy density is increased, the effective range of the electrode active material layer can be increased, and the battery efficiency can be improved.

Further, the active material uncoated portions 2A of the positive electrode plate 2 are provided between the active material coated portions 22a and 22b located on both sides in the width direction Y, and the active material uncoated portions 3A of the negative electrode plate 3 are provided in the width direction Y. It is provided between the active material coated portions 32a and 32b located on both sides of the above, and these active material uncoated portions 2A and 3A are formed as terminal tabs 4 and 5, respectively. It is possible to achieve a well-balanced increase in the effective range of the electrode active material layer while maintaining the effect.

Further, the positive electrode cutting portion 24 is provided along the boundary line between the active material uncoated portion 2A of the positive electrode plate 2 and the active material coated portions 22a and 22b located on both sides of the active material uncoated portion 2A in the width direction Y. Is formed, and the negative electrode is formed along the boundary line between the active material uncoated portion 3A of the negative electrode plate 3 and the active material coated portions 32a and 32b located on both sides in the width direction Y of the active material uncoated portion 3A. Since the cut portion 34 is formed, the terminal tabs 4 and 5 of the active material uncoated portions 2A and 3A formed only by the current collectors 21 and 31 are the active material coated portions 22a on both sides in the width direction Y. It is in a state of being separated from 22b, 32a, and 32b. Therefore, the terminal tabs 4, 5 can be curved so that the portions connected to the active material coating portion in the length direction X are the base ends 21a, 31a, and the terminal tabs 4, 4, ... 5, 5, ...) Can be reliably connected to each other by welding or the like.

Further, in the positive electrode plate 2 and the negative electrode plate 3, a notch recess 23 is formed in the central portion in the width direction Y on the other end side opposite to the one end side on which the terminal tabs 4 and 5 are formed in the length direction X. Since 33 is formed, in a configuration in which the positive electrode plate 2 and the negative electrode plate 3 are laminated with each other, the current collectors 21 and 31 are not arranged in the stacking direction of the tabs 4 and 5 for each terminal, and the positive electrode plate is not arranged. The terminal tabs 4, 4, ... Of 2 and the terminal tabs 5, 5, ... Of the negative electrode plate 3 can be stacked and connected in the stacking direction.

Further, in the present embodiment, the active material uncoated portion 2A (3A) is provided in the central portion in the width direction Y in a plan view, and the active material is applied to both sides of the active material uncoated portion 2A (3A) in the width direction Y. The portions 22a and 22b (32a and 32b) are formed, and the terminal tab 4 (5) can be held in a state of being sandwiched between the active material coating portions 22a and 22b (32a and 32b).

Further, in the present embodiment, the terminal tabs 4 and 5 interposed in the notch recesses 23 and 33 are located on both sides of the notch recesses 23 and 33 in the width direction Y, and the active material coating portions 22a and 22b (32a, Since the space sandwiched by the current collectors 21 and 31 forming 32b) is formed, the terminal tabs 4 and 5 can be compactly accommodated. The same applies when an extension tab, which will be described later, is connected.

Further, in the present embodiment, the electrode active material layers 22 and 32 of the positive electrode plate 2 and the negative electrode plate 3 can be formed in the range of the total length of the lithium ion secondary battery 1 in the length direction X, and the electrode active material layer can be formed. The effective range of 22 and 32 can be effectively increased.

As described above, in the method for manufacturing a lithium ion secondary battery according to the present embodiment, the battery performance can be improved by increasing the effective range of the electrode active material layers 22 and 32.

Although the embodiment of the method for manufacturing a lithium ion secondary battery according to the present invention has been described above, the present invention is not limited to the above embodiment and can be appropriately modified without departing from the spirit of the present invention. ..

For example, as in the second modification shown in FIG. 6, welding or the like is performed in a state where the extension tab 7 is further overlapped on the surface of the terminal tab 4 (5) shown in FIGS. 2 and 3 of the above-described embodiment. A lithium ion secondary battery 1A having a configuration connected by the above may be used. In this case, as shown in FIG. 5, since the length of the tab can be increased, the extension tabs 7A, 7A, ... Connected to the terminal tags 4 of the plurality of laminated positive electrode plates 2 can be connected to each other. It is possible to easily realize a connection structure in which extension tabs 7B, 7B, ... Connected to one and connected to terminal tags 5 of a plurality of laminated negative electrode plates 3 are connected to each other.

Further, in the present embodiment, the notch recesses 23 and 33 are formed at the other ends of the positive electrode plate 2 and the negative electrode plate 3 in the length direction X, respectively, but the notch recesses 23 and 33 are omitted. Is also possible. The positions of the notch recesses 23 and 33 are not limited to the positions of the central portions in the width direction Y.

Further, in the above-described embodiment, the active material uncoated portions 2A and 3A (terminal tabs 4 and 5) of the positive electrode plate 2 and the negative electrode plate 3 are provided at the central portion in the width direction Y in a plan view. The position in the width direction Y is not limited to the central portion, and may be, for example, a position closer to either one of the width directions Y. The point is that the active material uncoated portion may be provided in a part of the width direction Y in a plan view.

Further, as in the third modification shown in FIG. 7, active material uncoated portions 2A and 3A are formed on one end side of the current collectors 21 and 31 of the positive electrode plate 2 and the negative electrode plate 3 in the length direction X, respectively. The notch recesses 23 and 33 notched from the current collectors 21 and 31 may be formed at intervals in the width direction Y. Also in this case, the cut portions 24 and 34 are formed along the boundary line between the active material uncoated portions 2A and 3A and the active material coated portions located on both sides in the width direction Y.

Further, in the fourth modification shown in FIG. 8, one of the electrodes composed of the positive electrode plate 2 and the negative electrode plate 3 is located on one end side of the current collectors 21 and 31 in the length direction X, and is viewed in a plan view. The active material uncoated portions 2A and 3A are provided in a part of the width direction Y, and the current collectors 21 and 31 are cut at one end edges 21c and 31c of the width direction Y adjacent to one end side of the current collectors 21 and 31. The notched recesses 23 and 33 are formed. Although not shown, referring to FIG. 8, the other electrode of the electrodes composed of the positive electrode plate 2 and the negative electrode plate 3 is located at one end edges 21c and 31c, and is a part of the length direction X in a plan view. The active material uncoated portions 2A and 3A are provided in the above, and notch recesses 23 and 33 notched from the current collectors 21 and 31 are formed on one end side of the current collectors 21 and 31 in the length direction X. Then, the active material uncoated portions 2A and 3A form tabs for terminals.

Furthermore, the configuration of the shape of the electrode laminate 10, the laminated structure, the material, the width dimension of the active material uncoated portions 2A and 3A in the width direction Y, the thickness of the electrode active material layers 22 and 32, and the like are also described above. It is not limited to the form, and can be set as appropriate.

In addition, it is possible to replace the components in the above-described embodiment with well-known components as appropriate without departing from the spirit of the present invention.

1, 1A lithium ion secondary battery 2 Positive electrode plate (positive electrode)
2A Active material uncoated part 3 Negative electrode plate (negative electrode)
3A Active material uncoated part 4 Terminal tab on the positive electrode plate side 5 Terminal tab on the negative electrode plate side 6 Separator 7, 7A, 7B Extension tab 10 Electrode laminate 21 Positive electrode current collector 22 Positive electrode active material layer (electrode active material) layer)
22a, 22b Active material coating part 23 Positive electrode notch recess 24 Positive electrode cutting part 31 Negative electrode current collector 32 Negative electrode active material layer (electrode active material layer)
32a, 32b Active material coating part 33 Negative electrode notch recess 34 Negative electrode cutting part X Length direction Y Width direction

Claims (11)

Provided is an electrode laminate formed by alternately laminating a positive electrode and a negative electrode formed by coating an active material on the surface of a current collector with an uncoated portion of the active material formed via an insulator. Lithium-ion secondary battery
The electrode composed of the positive electrode and the negative electrode is
The active material uncoated portion is located on one end side in the length direction extending in one direction of the current collector, and is provided in a part in the width direction orthogonal to the length direction in a plan view.
The active material uncoated portion to name a terminal tab,
In the current collector, a cut portion is formed along a boundary line between the active material uncoated portion and the active material coated portion located on both sides of the active material uncoated portion in the width direction. lithium-ion secondary battery wherein the active material uncoated portion cut out by the cutting unit, characterized in Succoth such a terminal tab. The lithium ion secondary battery according to claim 1, wherein the active material uncoated portions are located at both ends in the length direction. The lithium ion secondary battery according to claim 1 or 2 , wherein the extension tab is connected to the terminal tab in an overlapping state. The lithium ion secondary battery according to any one of claims 1 to 3 , wherein the active material uncoated portion is provided at a central portion in the width direction in a plan view. The active material uncoated portion is located on one end side in the length direction extending in one direction of the current collector.
The lithium according to any one of claims 1 to 3 , wherein a notch recess is formed in a part of the width direction on the other end side of the current collector in the length direction. Ion secondary battery. The lithium ion secondary battery according to claim 5 , wherein the notch recess is formed in a central portion in the width direction. On one end side of the current collector in the length direction, the active material uncoated portion and the notch recess notched in the current collector are formed at intervals in the width direction. The lithium ion secondary battery according to any one of claims 1 to 3 , wherein the lithium ion secondary battery is characterized. Provided is an electrode laminate formed by alternately laminating a positive electrode and a negative electrode formed by coating an active material on the surface of a current collector with an uncoated portion of the active material formed via an insulator. Lithium-ion secondary battery
One of the electrodes composed of the positive electrode and the negative electrode is located on one end side in the length direction extending in one direction of the current collector, and is a part of the width direction orthogonal to the length direction in a plan view. An active material uncoated part is provided,
The other electrode is located at one end edge in the width direction adjacent to the one end side, and the active material uncoated portion is provided in a part in the length direction in a plan view.
The active material uncoated portion to name a terminal tab,
The one electrode is formed with a notch recess in which the current collector is cut out at one end edge in the width direction adjacent to the one end side of the current collector.
The other electrode is a lithium ion secondary battery characterized in that a notched recess notched in the current collector is formed on one end side in a length direction extending in one direction of the current collector. A plurality of lithium ion secondary batteries according to any one of claims 5 to 8 are connected, and the notch recess of the first electrode of either the positive electrode or the negative electrode is connected to the first electrode. It is formed in a region overlapping the terminal tab of the other second electrode of the positive electrode and the negative electrode to be laminated with each other.
A lithium ion secondary battery characterized in that the terminal tabs of the first electrode and the terminal tabs of the second electrode, which overlap in the stacking direction, are connected to each other. The ninth aspect of claim 9, wherein the length dimension of the electrode active material layer formed on the laminated electrodes in the length direction is the same for all the electrodes constituting the electrode laminate. Lithium-ion secondary battery. Provided is an electrode laminate formed by alternately laminating a positive electrode and a negative electrode formed by coating an active material on the surface of a current collector with an uncoated portion of the active material formed via an insulator. This is a method for manufacturing lithium-ion secondary batteries.
A state in which an active material uncoated portion is left at a position on one end side in the length direction extending in one direction of the current collector and in a central portion in the width direction orthogonal to the length direction in a plan view. The process of applying the active material to the surface and
A step of forming a notch recess in the central portion in the width direction on the other end side of the current collector in the length direction, and
In the current collector, a cut portion is formed along a boundary line between the active material uncoated portion and the active material coated portion located on both sides in the width direction of the active material uncoated portion. A step of forming the uncoated portion of the active material cut out by the cut portion as a tab for terminals, and
For the terminal tabs of the first electrode of one of the positive electrode and the negative electrode overlapping in the stacking direction, and for the terminal of the other second electrode of the positive electrode and the negative electrode laminated with respect to the first electrode. The process of connecting the tabs and
Have,
A method for manufacturing a lithium ion secondary battery, wherein the notch recess of the first electrode is formed in a region overlapping the terminal tab of the second electrode.

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