JP6926672B2 - Secondary battery and manufacturing method of secondary battery - Google Patents

Description

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

In recent years, the battery capacity has been increasing year by year in response to demands such as extension of the cruising range of automobiles, increase of power consumption of mobile devices, and extension of usage time. Along with this, there is an increasing demand for quick charging.

The battery capacity is determined by the ratio of the active material contained in the battery, and the capacity can be increased by thickening the active material layer. However, as the active material layer becomes thicker, the ion diffusion distance also increases, and as a result, the battery It causes deterioration of the input / output characteristics of.

Therefore, in order to improve the input / output characteristics of the battery, a fine three-dimensional electrode structure formed in the thickness direction of the active material layer has been studied, and such an electrode structure is disclosed in, for example, Patent Document 1. There is a comb-like three-dimensional structure that looks like it is.

International Publication No. 2008/072638

However, if a fine three-dimensional structure protruding in the thickness direction of the active material layer is provided as in the above-mentioned prior art, the structure is broken when the active material layer is pressed from the thickness direction in the manufacturing process. There is a fear.

Pressing in the manufacturing process is performed, for example, to improve the adhesiveness between members to reduce electrical resistance and to control the porosity in the active material layer. Even if an electrode having the original structure is manufactured, it is difficult for it to exhibit a predetermined performance.

Therefore, it cannot be said that the three-dimensional structure as in the above-mentioned prior art is sufficient to improve the input / output characteristics without rebounding to other battery performance (energy density, durability, etc.). Met.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a secondary battery and a method for manufacturing a secondary battery, which can further contribute to the improvement of input / output characteristics.

The secondary battery of the present invention for achieving the above object has one active material layer, a separator, another active material layer, and a separator alternately in the stacking direction. Conductive terminals are provided so as to project from one active material layer. The other active material layer has an electrical polarity different from that of one active material layer, and is projected in a state where the conductive terminal is connected to a part in the plane direction.

In the method for manufacturing a secondary battery of the present invention for achieving the above object, one sheet material and another sheet material are alternately laminated. One sheet material has one active material layer on the surface of the separator, and conductive terminals are provided so as to project from the one active material layer. The other sheet material has another active material layer on the surface of the separator, and is projected from the other active material layer in a state where the conductive terminals are connected to a part in the surface direction. One sheet material and the other sheet material are alternately laminated with a separator interposed therebetween.

According to the secondary battery having the above configuration and the method for manufacturing the secondary battery, it can further contribute to the improvement of the input / output characteristics.

It is sectional drawing which shows the lithium ion secondary battery of 1st Embodiment. It is a figure seen from the reference numeral 2 of FIG. It is an exploded view of the lithium ion secondary battery of 1st Embodiment. It is a figure which shows typically the inverse proportion different from the embodiment. It is a figure which shows typically the main part of the lithium ion secondary battery of 1st Embodiment. It is sectional drawing which shows the lithium ion secondary battery of 2nd Embodiment. It is sectional drawing which follows the 7-7 line of FIG. It is a figure which shows the modification of the conductor of 2nd Embodiment. It is a figure which shows the other modification of the conductor of 2nd Embodiment. It is sectional drawing which shows the lithium ion secondary battery of 3rd Embodiment. It is a figure which shows the conductor and the separator of 3rd Embodiment. It is a figure which shows a part of the manufacturing process of the lithium ion secondary battery of 3rd Embodiment. It is a figure which shows a part of the manufacturing process of the lithium ion secondary battery of 3rd Embodiment. It is sectional drawing which shows the lithium ion secondary battery of Example 1. FIG. It is a figure which shows a part of the manufacturing process of the lithium ion secondary battery of Example 1. It is a figure which shows a part of the manufacturing process of the lithium ion secondary battery of Example 1. It is a figure which shows a part of the manufacturing process of the lithium ion secondary battery of Example 1. It is a figure which shows a part of the manufacturing process of the lithium ion secondary battery of Example 1. It is sectional drawing which shows the lithium ion secondary battery of Example 2. It is sectional drawing which shows the lithium ion secondary battery of Example 3. FIG. It is sectional drawing which shows the lithium ion secondary battery of the comparative example 1. FIG. It is sectional drawing which shows the lithium ion secondary battery of the comparative example 2. It is a graph which shows one result of the charge / discharge test of Example 1 and Comparative Example 1. It is a graph which shows the other result of the charge / discharge test of Example 1 and Comparative Example 1. It is a graph which shows the other result of the charge / discharge test of Example 1 and Comparative Example 1.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. The dimensional ratios in the drawings are exaggerated for convenience of explanation and differ from the actual ratios.

<First Embodiment>
As shown in FIG. 1, the lithium ion secondary battery 100 of the first embodiment has a negative electrode active material layer 110 (one active material layer), a separator 120, and a positive electrode active material layer 130 (another active material layer). And the separator 120 are alternately provided in the stacking direction S. Further, the lithium ion secondary battery 100 has a negative electrode tab 111 (terminal), a positive electrode tab 131 (terminal), and a laminated film 140.

The negative electrode active material layer 110 contains negative electrode active material particles, a conductive auxiliary agent such as metal or carbon, and a polymer such as vinyl resin or urethane resin.

The constituent materials of the negative electrode active material particles contained in the negative electrode active material layer 110 include, for example, graphite, amorphous carbon, a fired polymer compound, coke, carbon fibers, a conductive polymer, tin, silicon, a metal alloy, and lithium. It is a composite oxide with a transition metal. At least a portion of the surface of the negative electrode active material particles is covered with a conductive additive and a polymer.

The negative electrode tab 111 projects from the negative electrode active material layer 110 in a state of being partially connected to the negative electrode active material layer 110 in the plane direction P, and has conductivity. The constituent material of the negative electrode tab 111 is, for example, a metal such as aluminum, nickel, iron, stainless steel, titanium, and copper, but the present invention is not limited to this, and may be a conductive polymer or a conductive filler. It may be a material containing a resin.

The negative electrode tabs 111 are provided on each of the plurality of negative electrode active material layers 110, and the plurality of negative electrode tabs 111 are joined to each other at the ends and electrically connected to each other.

The separator 120 is a porous insulator made of, for example, a polymer or a non-woven fabric, and exhibits ionic permeability and electrical conductivity by permeation of an electrolytic solution.

The positive electrode active material layer 130 contains the positive electrode active material particles and also contains the same conductive auxiliary agent and polymer as those contained in the negative electrode active material layer 110.

The constituent material of the positive electrode active material particles is, for example, a composite oxide of lithium and a transition metal. The composite oxide of lithium and the transition metal is, for example, LiCoO ₂ , LiNiO ₂ , LiMnO _2, LiMn ₂ O _4, or a mixture thereof. At least a portion of the surface of the positive electrode active material particles is covered with a conductive additive and a polymer.

The positive electrode tab 131 is projected from the positive electrode active material layer 130 in a state of being partially connected to the positive electrode active material layer 130 in the plane direction P, and has conductivity. The constituent material itself of the positive electrode tab 131 is the same as the constituent material of the negative electrode tab 111.

In the present embodiment, the positive electrode tab 131 projects in the same direction as the negative electrode tab 111, but the positive electrode tab 131 may project in the opposite direction.

The positive electrode tabs 131 are provided in each of the plurality of positive electrode active material layers 130, and the plurality of positive electrode tabs 131 are joined to each other at the ends and electrically connected to each other.

The amount of the conductive additive contained in the negative electrode active material layer 110 and the positive electrode active material layer 130 is not particularly limited, but is preferably 5 wt% to 10 wt%. Further, the constituent material of the conductive auxiliary agent is not particularly limited, but fibrous carbon or carbon nanotubes is preferable.

When the amount of the conductive auxiliary agent added is 5 wt% or more, the electron conductivity in the plane direction P is ensured in a wide range of the negative electrode active material layer 110 and the positive electrode active material layer 130, and good long-term durability can be obtained. When the amount of the conductive auxiliary agent added is 10 wt% or less, the decrease in energy density can be suppressed.

Further, if the constituent material of the conductive auxiliary agent is fibrous carbon or carbon nanotubes, electron conductivity over a relatively long distance can be obtained in the plane direction P, and the negative electrode active material layer 110 and the positive electrode active material layer 130 can obtain electron conductivity. Electrons can easily move over long distances.

The laminated film 140 is an exterior material that covers the above components, and encloses an electrolytic solution together with those components.

The electrolytic solution contains, for example, an organic solvent composed of propylene carbonate (PC) and ethylene carbonate (EC), and a lithium salt (LiPF ₆ ) as a supporting salt. As the organic solvent, other cyclic carbonates, chain carbonates such as dimethyl carbonate, and ethers such as tetrahydrofuran can be applied. As the lithium salt, other inorganic acid anion salts and organic acid anion salts such as _{LiCF 3} SO _{3 can be applied.}

The laminated film 140 has, for example, a structure in which polypropylene (PP), aluminum, and nylon are laminated in this order, but is not limited to this structure.

At the edge 141 of the laminated film 140, the end portion of the negative electrode tab 111 and the end portion of the positive electrode tab 131 are pulled out while maintaining the liquidtight state.

As shown in FIG. 2, the negative electrode tab 111 and the positive electrode tab 131 are drawn out from positions separated from each other on the same edge 141, but are not limited thereto.

For example, one of the negative electrode tab 111 and the positive electrode tab 131 may be drawn from the edge 141, and the other of them may be drawn from the edge 142 facing the edge 141. In this case, each of the tab pull-out point at the edge 141 and the tab pull-out point at the edge 142 is not particularly limited, and is not a part of each of the edge 141 and the edge 142, but each of the edge 141 and the edge 142, respectively. Wide tabs may be pulled out throughout.

Next, a method for manufacturing the lithium ion secondary battery 100 will be described.

As shown in FIG. 3, in the manufacturing method of the present embodiment, each of the sheet material 150 (one sheet material) and the sheet material 160 (another sheet material) having different configurations is produced, and they are alternately laminated. Will be done. After being pressed in the stacking direction S, the laminates are covered with the laminate film 140 and sealed together with the electrolytic solution.

The sheet material 150 has a configuration in which the negative electrode tab 111 is projected from the negative electrode active material layer 110 arranged on the surface of the separator 120 in a state of being connected to a part in the surface direction P.

The sheet material 150 is produced, for example, by arranging the negative electrode tabs 111 on the surface of the separator 120 and forming the negative electrode active material layer 110 on them. The negative electrode active material layer 110 is formed by coating a negative electrode slurry containing negative electrode active material particles and the like and drying the negative electrode slurry. The negative electrode slurry used here contains, for example, a conductive auxiliary agent, a polymer, and the like in addition to the negative electrode active material particles, and is prepared by mixing them with a solvent.

The sheet material 160 has a configuration in which the positive electrode tab 131 is projected from the positive electrode active material layer 130 arranged on the surface of the separator 120 in a state of being connected to a part in the surface direction P.

The sheet material 160 is produced, for example, by arranging the positive electrode tabs 131 on the surface of the separator 120 and forming the positive electrode active material layer 130 on them. The positive electrode active material layer 130 is formed by coating a positive electrode slurry containing positive electrode active material particles and the like and drying the positive electrode slurry. The positive electrode slurry used here contains, for example, a conductive auxiliary agent, a polymer, and the like in addition to the positive electrode active material particles, and is prepared by mixing them with a solvent.

The sheet material 150 and the sheet material 160 are alternately laminated with the separator 120 interposed therebetween. The number of these layers is not particularly limited.

Next, the action and effect of this embodiment will be described in comparison with the inverse proportion.

In the inverse proportion shown in FIG. 4, unlike the present embodiment, each of the conductive current collectors 101 and 103, such as a metal foil, is in the plane direction with respect to each of the negative electrode active material layer 110 and the positive electrode active material layer 130. It is not a part of P, but is projected in a state of being spread over the entire surface direction P.

Therefore, the diffusion of ions 1 is possible in each of the negative electrode active material layer 110 and the positive electrode active material layer 130 from only one side on the separator 120 side. Therefore, in inverse proportion, the maximum diffusion distance D1 of the ion 1 is the total thickness of the negative electrode active material layer 110, the separator 120, and the positive electrode active material layer 130.

On the other hand, as shown in FIG. 5, in the present embodiment, each of the negative electrode tab 111 and the positive electrode tab 131 is connected to a part of the negative electrode active material layer 110 and the positive electrode active material layer 130 in the plane direction P. It is thrust in the state.

Therefore, the diffusion of ions 1 is possible from both sides of each of the negative electrode active material layer 110 and the positive electrode active material layer 130.

Therefore, in the present embodiment, the maximum diffusion distance D2 of the ion 1 is the sum of half the thickness of each of the negative electrode active material layer 110 and the positive electrode active material layer 130 and the thickness of the separator 120, which is shorter than the inverse proportion. (D1> D2).

As described above, according to the present embodiment, since the diffusion distance of the ion 1 is shortened, both the charging performance and the discharging performance can be improved, and the input / output characteristics can be improved.

Further, according to the present embodiment, it is not necessary to provide, for example, a fine uneven three-dimensional structure in the thickness direction of the negative electrode active material layer 110 and the positive electrode active material layer 130 as in the conventional case, so that the stacking direction is in the manufacturing process. It is possible to press in S.

Therefore, this embodiment is excellent in practicality and can contribute to further improvement of input / output characteristics.

Further, since a general lithium ion secondary battery has a relatively low ionic conductivity as compared with a secondary battery using an aqueous electrolyte such as a lead storage battery or a nickel hydrogen battery, the ion 1 can be used as in the present embodiment. If the diffusion distance is shortened, a greater effect can be obtained.

<Second Embodiment>
As shown in FIG. 6, the lithium ion secondary battery 200 of the second embodiment is different from the first embodiment in that it has a conductor 270. Since the present embodiment is substantially the same as the first embodiment with respect to other configurations, the same reference numerals are given and duplicate description will be omitted. Further, the manufacturing method is also different in the present embodiment only in that the conductors 270 are provided in the sheet materials 150 and 160 of the first embodiment, and thus the duplicate description here will be omitted.

The conductor 270 is arranged so as to be embedded in a part of the negative electrode active material layer 110 and the positive electrode active material layer 130 in each surface direction P.

In the present embodiment, the conductor 270 is provided in both the negative electrode active material layer 110 and the positive electrode active material layer 130, but the present invention includes a mode in which the conductor 270 is provided in one of them. Further, the conductor 270 is not arranged so as to be embedded in each of the negative electrode active material layer 110 and the positive electrode active material layer 130 as in the present embodiment, but is arranged with respect to their surfaces. And may be located between them and the separator 120.

The conductor 270 is electrically connected to each of the negative electrode tab 111 and the positive electrode tab 131, and can be formed of a conductive constituent material as well.

As shown in FIG. 7, the conductor 270 has a frame shape (skeleton shape).

The conductor 270 is arranged in a part of the negative electrode active material layer 110 and the positive electrode active material layer 130 in the direction along the surface (plane direction P), and is formed of the negative electrode active material layer 110 and the positive electrode active material layer 130. Since it does not cover the entire surface, the ion 1 can move in the thickness direction S orthogonal to those surfaces (see FIG. 5).

The conductor 270 is composed of a wire rod 271 forming four sides of the frame shape, but is not limited thereto. The conductor 270 may have another shape as long as it is composed of a wire rod extending in the plane direction P of the negative electrode active material layer 110 and the positive electrode active material layer 130.

For example, as shown in FIG. 8, the conductor 270 may have a grid-like skeleton shape, or may have a comb-teeth-like skeleton shape as shown in FIG. Further, the shape of the wire rod constituting the conductor 270 is not limited to a straight line, but may be a curved line. The dimensions and shape of the conductor 270 are designed, for example, in consideration of the energy density and especially the IR drop due to the electronic resistance of the active material layer.

In the present embodiment, the conductor 270 is arranged in the negative electrode active material layer 110 and the positive electrode active material layer 130, but the conductor 270 is arranged in a part of the surface direction P thereof and is arranged in the thickness direction. Since the movement of the ion 1 to S is not blocked, the same effect as that of the first embodiment can be obtained.

Further, by disposing the conductor 270 in at least one of the negative electrode active material layer 110 and the positive electrode active material layer 130, it functions as a conductive passage in the plane direction P, so that the current collecting performance can be further improved. The effect is obtained.

In particular, in the present embodiment, the conductor 270 has a frame shape (skeleton shape), so that the current collecting performance can be effectively improved.

<Third Embodiment>
As shown in FIG. 10, the lithium ion secondary battery 300 of the third embodiment is different from the first embodiment in that it has a conductor 370. Since the present embodiment is substantially the same as the first embodiment with respect to other configurations, the same reference numerals are given and duplicate description will be omitted.

The conductor 370 is arranged on each surface of the negative electrode active material layer 110 and the positive electrode active material layer 130, and a plurality of holes through which the ion 1 can pass are formed.

In the present embodiment, the conductor 370 is provided in both the negative electrode active material layer 110 and the positive electrode active material layer 130, and the present invention includes a mode in which the conductor 370 is provided in one of them.

The conductor 370 is electrically connected to each of the negative electrode tab 111 and the positive electrode tab 131, and can be formed of a conductive constituent material as well.

As shown in FIG. 11, the conductor 370 is a pattern coating formed on the surface of the separator 120 and has a mesh shape. The size and shape of the mesh, the pattern pitch, and the like are not particularly limited as long as the ions 1 can pass through, but are designed in consideration of, for example, energy density and IR drop.

Further, the form of the conductor 370 is not limited to the mesh-shaped pattern, and may be another pattern. Other patterns include, for example, a plurality of horizontal lines along the long side of the surface of the separator 120, a plurality of vertical lines along the short side of the surface of the separator 120, a plurality of diagonal lines along the diagonal of the surface of the separator 120, and a waveform. , Brick-shaped, lattice-shaped, rhombic-shaped, scaly-shaped, checkered pattern, etc., but are not particularly limited.

The distance between the lines forming these patterns is not particularly limited, but is preferably about 2 mm in order to ensure the conductivity of electrons.

As shown in FIG. 12, the negative electrode tab 111 is arranged with respect to the separator 120 on which the conductor 370 is formed, and the negative electrode active material layer 110 is formed on the negative electrode tab 111, whereby the sheet material of one of the present embodiments is formed. 350 is formed. The negative electrode tab 111 is in contact with the conductor 370 at the end and is electrically connected. The negative electrode active material layer 110 is formed by coating the negative electrode slurry 112 containing the negative electrode active material particles and the like and drying the negative electrode slurry 112.

On the other hand, as shown in FIG. 13, the positive electrode tab 131 is arranged with respect to the separator 120 on which the conductor 370 is formed, and the positive electrode active material layer 130 is formed on the positive electrode tab 131, whereby the other of the present embodiment is obtained. The sheet material 360 is formed. The positive electrode active material layer 130 is formed by coating a positive electrode slurry 132 containing positive electrode active material particles and the like and drying the positive electrode slurry 132.

The lithium ion secondary battery 300 is produced by alternately laminating the sheet material 350 and the sheet material 360 and sealing them together with the electrolytic solution by the laminating film 140. Since they are the same, the duplicate description here will be omitted.

In the present embodiment, the conductor 370 is arranged on the negative electrode active material layer 110 and the positive electrode active material layer 130, but the conductor 370 is arranged on those surfaces and the ion 1 can pass through. A plurality of holes are formed, and these configurations make it particularly difficult to block the movement of the ion 1 in the thickness direction (see FIG. 5).

This is a feature of the present embodiment that is different from the conventionally known current collector foil for the purpose of simply improving the adhesion to the active material layer and reducing the interfacial resistance, and thereby having the same peculiarity as the first embodiment. You can get the effect.

Further, in the present embodiment, since the conductor 370 functions as a conductive passage in the plane direction P, the effect that the current collecting performance can be further improved can be obtained. Further, since the conductor 370 is a pattern coating and existing process techniques such as printing, vapor deposition, or a 3D printer can be applied, the conductor 370 can be formed relatively easily.

<Example 1>
As shown in FIG. 14, the present inventors produced the lithium ion secondary battery 100A of Example 1 based on the configuration of the above embodiment.

Originally, it is desirable to verify the effect in the example of the configuration in which the positive and negative active material layers are laminated in multiple layers as in the above embodiment, but the effect of ion diffusion in both sides in the thickness direction of the active material layer is desired. In the example, we focused on one active material layer so that the ion diffusion as described above occurs there.

The lithium ion secondary battery 100A of Example 1 has a negative electrode active material layer 110A, a separator 120A, a positive electrode active material layer 130A, a separator 120A, and a negative electrode active material layer 110A alternately in the stacking direction. Further, the lithium ion secondary battery 100A has a negative electrode tab 111A, a positive electrode tab 131A, a laminate film 140A, and a conductor 170A.

The negative electrode active material layer 110A contains graphite. Separator 120A is Celgard® # 2400. The positive electrode active material layer 130A contains LiCoO ₂ (LCO). The negative electrode tab 111A is a copper foil. The conductor 170A is integrated with the positive electrode tab 131A and is made of aluminum expanded metal. The electrolytic solution is EC: DEC (diethyl carbonate) (1: 1 volume ratio) containing _{1 M of LiPF 6.}

Next, the production of the lithium ion secondary battery 100A will be described.

First, the production of the positive electrode active material layer 130A will be described.

The present inventors weighed the positive electrode active material (LCO: 90%, conductive additive: 5%, KF polymer # 7200: 5% manufactured by Kureha), stirred well, and then N-methyl until it showed moderate viscosity. The solid content ratio was adjusted by stirring while adding -2-pyrrolidone (NMP).

As shown in FIG. 15, the present inventors applied the adjusted positive electrode slurry 132A to the separator 120A so as to have a predetermined thickness, and removed NMP by vacuum heating and drying. The film thickness of the positive electrode active material layer 130A after drying was 25 μm.

As shown in FIG. 16, the present inventors set the conductor 170A integrated with the positive electrode tab 131A on the positive electrode active material layer 130A. The short-diameter SW of the mesh of the aluminum expanded metal constituting the conductor 170A is 1.0 mm, the long-diameter LW is 2.0 mm, the engraving width is 100 μm, and the plate thickness is 30 μm.

As shown in FIG. 17, the present inventors further applied the positive electrode slurry 132A to a predetermined thickness, and removed NMP by vacuum heating and drying. In the sheet material 160A produced after drying, the thickness of the positive electrode active material layer 130A was 72 μm.

The production of the negative electrode active material layer 110A will be described.

The present inventors weighed the negative electrode active material (graphite: 90%, conductive additive: 5%, KF polymer # 7200: 5% manufactured by Kureha), stirred well, and then added NMP until it showed moderate viscosity. The solid content ratio was adjusted by stirring while stirring.

The present inventors applied the adjusted negative electrode slurry to the copper foil integrated with the negative electrode tab 111A so that the balance between the negative electrode capacity and the positive electrode capacity was in the range of 1.2 to 1.3. NMP was removed by vacuum heating and drying. The thickness of the negative electrode active material layer 110A produced after drying was 28 μm.

The subsequent process will be described.

As shown in FIG. 18, the present inventors arrange the negative electrode active material layer 110A with the copper foil integrated with the negative electrode tab 111A on the lower side, and arrange the sheet material 160A and the separator 120A on the negative electrode active material layer 110A. Further, the negative electrode active material layer 110A was arranged on the negative electrode active material layer 110A with the copper foil integrated with the negative electrode tab 111A on the upper side.

After that, the present inventors brought the laminated members into close contact with each other by a roll press. After inserting the obtained laminate into the three-way sealed laminate film 140A, the present inventors injected the electrolytic solution. After the liquid injection, the present inventors sealed the negative electrode tab 111A and the positive electrode tab 131A with the negative electrode tab 111A and the positive electrode tab 131A protruding from the opening to obtain the lithium ion secondary battery 100A shown in FIG.

<Example 2>
As shown in FIG. 19, the lithium ion secondary battery 100B of Example 2 is different from Example 1 in that it has a negative electrode active material layer 110B and a positive electrode active material layer 130B having a thickness thinner than that of Example 1. Regarding other configurations, Example 2 is the same as Example 1.

The film thickness of the negative electrode active material layer 110B is 17 μm, and the film thickness of the positive electrode active material layer 130B is 50 μm.

The present inventors use the same manufacturing method as in Example 1 to obtain the above-mentioned film thickness while considering that the balance between the negative electrode capacity and the positive electrode capacity is in the range of 1.2 to 1.3. 100B was prepared.

<Example 3>
As shown in FIG. 20, in Example 3, the positive and negative active material layers were exchanged with those of Example 1.

The lithium ion secondary battery 100C of Example 3 has a positive electrode active material layer 130C, a separator 120A, a negative electrode active material layer 110C, a separator 120A, and a positive electrode active material layer 130C alternately in the stacking direction. Further, the lithium ion secondary battery 100C has a negative electrode tab 111C, a positive electrode tab 131C, a laminate film 140A, and a conductor 170C.

The constituent materials themselves are substantially the same as those of Examples 1 and 2, and are as follows. The positive electrode active material layer 130C contains LiCoO ₂ (LCO). The negative electrode active material layer 110C contains graphite. Separator 120A is Celgard® # 2400. The positive electrode tab 131C is an aluminum foil. The conductor 170C is integrated with the negative electrode tab 111C, and is made of copper expanded metal (minor diameter SW is 1.0 mm, major diameter LW is 2.0 mm, engraving width is 100 μm, and plate thickness is 30 μm). The electrolytic solution is EC: DEC (1: 1 volume ratio) containing _{1 M of LiPF 6.}

In Example 3, the thickness of the negative electrode active material layer 110C was 60 μm, and the thickness of the positive electrode active material layer 130C was 33 μm. Regarding the production method, Example 3 was based on the method of Example 1.

<Comparative example 1>
As shown in FIG. 21, the present inventors made a lithium ion secondary battery 1000A of Comparative Example 1 for comparison with Example 1.

The lithium ion secondary battery 1000A has a negative electrode active material layer 1010A, a separator 120A, and a positive electrode active material layer 1030A, and a negative electrode tab 1011A, a positive electrode tab 1031A, and a laminate film 140A.

The negative electrode active material layer 1010A is made of the same material as the negative electrode active material layer 110A of Example 1, but has a different thickness. The thickness of the negative electrode active material layer 1010A is 55 μm.

The negative electrode active material layer 1010A is formed by applying the negative electrode slurry prepared in Example 1 to a predetermined thickness on a copper foil (10 μm) integrated with the negative electrode tab 1011A, and then removing NMP by vacuum heating and drying. It is made.

The positive electrode active material layer 1030A is made of the same material as the positive electrode active material layer 130A of Example 1, but has a different thickness. The thickness of the positive electrode active material layer 1030A is 66 μm.

The positive electrode active material layer 1030A is formed by applying the positive electrode slurry prepared in Example 1 to a predetermined thickness on an aluminum foil (22 μm) integrated with the positive electrode tab 1031A, and then removing NMP by vacuum heating and drying. It is made.

The separator 120A is the same as in the first embodiment. This is sandwiched between the negative electrode active material layer 1010A and the positive electrode active material layer 1030A prepared as described above, and they are brought into close contact with each other by a roll press.

Then, they were sealed together with the electrolytic solution with a laminate film 140A to prepare a lithium ion secondary battery 1000A. The electrolytic solution is the same as in Example 1.

<Comparative example 2>
As shown in FIG. 22, the present inventors made the lithium ion secondary battery 1000B of Comparative Example 2 for comparison with Example 2 in which the active material layer was thinner than that of Example 1.

The lithium ion secondary battery 1000B of Comparative Example 2 is different from Comparative Example 1 in that it has a negative electrode active material layer 1010B and a positive electrode active material layer 1030B which are thinner than Comparative Example 1. Regarding other configurations, Comparative Example 2 is the same as Comparative Example 1.

The film thickness of the negative electrode active material layer 1010B is 34 μm, and the film thickness of the positive electrode active material layer 1030B is 44 μm.

The present inventors use the same manufacturing method as in Comparative Example 1 to obtain the above-mentioned film thickness while considering that the balance between the negative electrode capacity and the positive electrode capacity is in the range of 1.2 to 1.3. 1000B was prepared.

<Charge / discharge test>
The present inventors conducted charge / discharge tests for each of Examples 1 to 3 and Comparative Examples 1 and 2. The charge / discharge test was performed after the initial charge and the initial discharge.

The initial charge was performed in a constant current-constant voltage mode (CC-CV), and the applied current was 0.1 C, the CV voltage was 4.2 V, the CV end condition was 0.05 C, and the temperature was 30 ° C.

The initial discharge was performed in a constant current mode (CC), and the discharge current was 0.1 C, the Cut-off voltage was 2.7 V, the rest time was 10 minutes, and the temperature was 30 ° C.

Charging in the charge / discharge test was performed in a constant current-constant voltage mode (CC-CV), and the applied current was 0.1 C, the CV voltage was 4.2 V, the CV end condition was 0.05 C, and the temperature was 30 ° C.

The discharge in the charge / discharge test was performed in the constant current mode (CC), and the Cut-off voltage was 3.2 V and the temperature was 30 ° C. Further, the discharge in the charge / discharge test was performed with each discharge current of 1C, 5C, and 10C.

FIGS. 23 to 25 show a comparison of the discharge capacity ratios obtained in the charge / discharge tests of Example 1 and Comparative Example 1. The discharge capacity ratio is a value obtained by normalizing the capacity at 3.2 V when discharged at 0.1 C to 1.0.

It can be seen that at each C rate, the discharge capacity ratio of Example 1 is larger than the discharge capacity ratio of Comparative Example 1. The larger the C rate, the larger the difference between Example 1 and Comparative Example 1, and it was clarified that the examples showed good discharge characteristics.

Table 1 below summarizes the characteristic configurations of Examples 1 to 3 and Comparative Examples 1 and 2 and the results of the discharge capacity ratio.

In Example 2 and Comparative Example 2, since the film was thinner than in Example 1 and Comparative Example 1, the effect of improving the discharge performance was reduced at a low rate of 1C, but there was still a large difference in the discharge capacity ratio between 5C and 10C. It was confirmed that the improvement effect was great.

Further, in Example 3, the positive and negative active material layers are exchanged with those in Example 1, but the discharge capacity ratio equal to or slightly higher than that of Example 1 is obtained, and the positive and negative active materials are obtained. It was confirmed that the same effect can be obtained even if the material layer is replaced. Further, in the examples, the effect was verified by focusing on one active material layer, but the same effect can be expected even with a multi-layered laminated structure as in the embodiment.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims.

For example, the secondary battery of the present invention is not limited to the lithium ion secondary battery, and may be another secondary battery.

Further, although the example was carried out with an aluminum laminated film type battery, the idea of the present invention can also be applied to a coin type cell, a square type cell, a cylindrical type cell and the like.

Further, a mesh structure like the conductor 370 of the third embodiment may be provided inside the frame of the conductor 270 of the second embodiment.

Further, the present invention includes, in addition to the conductor 370 of the third embodiment, a conductor made of a metal non-woven fabric or the like having a plurality of holes through which ions can pass.

100, 200, 300 Lithium-ion secondary battery (secondary battery),
110 Negative electrode active material layer (one active material layer),
111 Negative electrode tab (terminal),
120 separator,
130 Positive electrode active material layer (other active material layer),
131 Positive electrode tab (terminal),
140 laminated film,
150 one sheet material,
160 Other sheet materials,
270 conductor,
271 wire rod,
370 conductor,
S stacking direction,
P plane direction.

Claims (5)

One active material layer with conductive terminals protruding from it,
Separator and
With another active material layer having an electrical polarity different from that of the one active material layer and projecting in a state where the conductive terminals are connected to a part in the plane direction.
Possess alternating with separators, a in the stacking direction,
A conductor integrated with the terminal is disposed in a part of the one active material layer and at least one of the other active material layers in the plane direction.
A secondary battery in which the conductor is arranged on the outer surface of at least one of the one active material layer and the other active material layer, and a plurality of holes through which ions can pass are formed. The secondary battery according to claim 1, wherein the conductor has a skeleton shape composed of a wire rod extending in the plane direction. The secondary battery according to claim 1 or 2, wherein the conductor is a pattern coating formed on the surface of the separator. The secondary battery according to any one of claims 1 to 3, which is a lithium ion secondary battery. A single active material layer is provided on the surface of the separator, and a conductive terminal is provided so as to project from the one active material layer, and the terminal is formed on a part of the one active material layer in the surface direction. A conductor integrated with the above is arranged, and the conductor is arranged on the outer surface of the one active material layer, and is formed with a plurality of holes through which ions can pass.
The other active material layer is provided on the surface of the separator, and the conductive terminals are projected from the other active material layer in a state of being connected to a part in the surface direction, and the other active material layer is formed. A conductor integrated with the terminal is disposed on a part of the surface direction of the above, and the conductor is arranged on the outer surface of the other active material layer to form a plurality of holes through which ions can pass. With other sheet materials,
A method for manufacturing a secondary battery, in which the separators are alternately laminated so as to be interposed .

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