Battery cell, secondary battery, method for manufacturing battery cell, and method for manufacturing secondary battery
阅读说明:本技术 电池单元片、二次电池、电池单元片的制造方法以及二次电池的制造方法 (Battery cell, secondary battery, method for manufacturing battery cell, and method for manufacturing secondary battery ) 是由 加贺祐介 广冈诚之 西村悦子 关荣二 尼崎新平 于 2019-06-26 设计创作,主要内容包括:本发明提供电池单元片、二次电池、电池单元片的制造方法和二次电池的制造方法。提供在使用挥发性高的成分的情况下也抑制挥发所引起的电解质组成的变动且不会导致电池性能的降低的电池单元片和二次电池。如下那样构成电池单元片,具有:具有电极集电体、和形成于其上下两表面的电极混合剂层的电极;层叠于电极的上下两表面的第一以及第二半固体电解质层;和分别粘接并覆盖于各半固体电解质层的与所述电极层叠的面的相反侧的面并将电极和第一以及第二半固体电解质层密封的第一以及第二密封片,在电极的电极混合剂层与各半固体电解质层之间具有非水溶液,在第一以及第二密封片的端边部具有密封部。(The invention provides a battery cell, a secondary battery, a method for manufacturing the battery cell, and a method for manufacturing the secondary battery. Provided are a battery cell and a secondary battery, wherein even when a highly volatile component is used, variation in the composition of an electrolyte due to volatilization is suppressed, and degradation in battery performance is not caused. A battery cell is configured as follows, and is provided with: an electrode having an electrode collector and electrode mixture layers formed on both upper and lower surfaces thereof; first and second semi-solid electrolyte layers laminated on upper and lower surfaces of the electrode; and first and second sealing sheets which are bonded to and cover surfaces of the semi-solid electrolyte layers on the opposite side of the surface on which the electrodes are stacked, respectively, and which seal the electrodes and the first and second semi-solid electrolyte layers, wherein the nonaqueous solution is provided between the electrode mixture layer of the electrodes and the semi-solid electrolyte layers, and the sealing sections are provided at edge portions of the first and second sealing sheets.)
1. A battery cell having:
an electrode having an electrode collector and electrode mixture layers formed on both upper and lower surfaces thereof;
first and second semi-solid electrolyte layers laminated on upper and lower surfaces of the electrode; and
first and second sealing sheets bonded to and covering surfaces of the semi-solid electrolyte layers opposite to surfaces of the semi-solid electrolyte layers on which the electrodes are stacked, respectively, and sealing the electrodes and the first and second semi-solid electrolyte layers,
a non-aqueous solution is provided between the electrode mix layer of the electrode and each of the semi-solid electrolyte layers,
the first and second seal sheets have seal portions at their end edges.
2. The battery cell of claim 1,
the seal portion is composed of a first seal portion formed by welding the first and second seal pieces to each other and integrating them, a second seal portion formed by welding the first and second semi-solid electrolyte layers to each other and integrating them, and a third seal portion formed by bonding the joint portions of the first and second semi-solid electrolyte layers and the electrode current collector to each other.
3. The battery cell of claim 1,
the sealing portion is composed of a second sealing portion in which the first and second semi-solid electrolyte layers are integrated by welding, and a third sealing portion in which the first and second semi-solid electrolyte layers and the joint portion of the electrode current collector are bonded to each other.
4. The battery cell of claim 3,
the first and second seal pieces are elongated toward the outer edges at the second and third seal portions.
5. The battery cell of claim 1,
the sealing sheet is formed of a resin film such as polyethylene terephthalate, polyethylene, polypropylene, or polyimide, or a film in which a metal foil such as stainless steel, aluminum, or copper is laminated on the resin film.
6. The battery cell of claim 1,
the non-aqueous solution includes at least 1 of a low viscosity solvent or a negative electrode interfacial stabilizer.
7. The battery cell of claim 6, wherein,
the low viscosity solvent is propylene carbonate, ethylene carbonate or a mixture thereof.
8. The battery cell of claim 6, wherein,
the negative electrode interface stabilizer is vinylene carbonate, ethylene fluorocarbon acid or a mixture thereof.
9. A method for manufacturing a battery cell, comprising the steps of:
coating electrode mixture layers on the upper and lower surfaces of an electrode collector to form electrodes;
adding a non-aqueous solution to both sides of the electrode mix layer of the electrode;
adding a non-aqueous solution to a semi-solid electrolyte layer while conveying a semi-solid electrolyte sheet composed of a semi-solid electrolyte and a sealing sheet by roll winding;
laminating the electrode and the first and second semi-solid electrolyte sheets with a first electrode mix layer on an upper surface side of the electrode and the semi-solid electrolyte layer of a first semi-solid electrolyte sheet provided to the upper surface side of the electrode facing each other, and a second electrode mix layer on a lower surface side of the electrode and the semi-solid electrolyte layer of a second semi-solid electrolyte sheet provided to the lower surface side of the electrode facing each other;
severing the first and second semi-solid electrolyte sheets; and
the heat-sealed portion heats and presses an edge side portion of a laminate in which the electrode and the first and second semisolid electrolyte sheets are laminated.
10. An apparatus for manufacturing a battery cell, comprising:
a first coating section for applying an electrode mix layer to both upper and lower surfaces of an electrode current collector to form an electrode, and adding a nonaqueous solution to both surfaces of the electrode mix layer;
a second coating section for applying a nonaqueous solution to a semi-solid electrolyte layer while conveying the semi-solid electrolyte sheet composed of a semi-solid electrolyte and a sealing sheet by roll winding;
a laminating roller section that laminates the electrode and the first and second semi-solid electrolyte sheets by opposing a first electrode mixture layer on an upper surface side of the electrode and the semi-solid electrolyte layer of a first semi-solid electrolyte sheet provided to the upper surface side of the electrode, and opposing a second electrode mixture layer on a lower surface side of the electrode and the semi-solid electrolyte layer of a second semi-solid electrolyte sheet provided to the lower surface side of the electrode;
a cutting section for cutting the first and second semi-solid electrolyte sheets; and
and a heat-seal section for forming a seal section by heating and pressing an edge side section of a laminate obtained by laminating the electrode and the first and second semi-solid electrolyte sheets.
11. A secondary battery having a plurality of secondary batteries,
and peeling off at least the upper sealing sheet on the laminated surface side to mount a battery cell, wherein the battery cell comprises:
an electrode having an electrode collector of a first polarity and electrode mix layers formed on both upper and lower surfaces thereof;
first and second semi-solid electrolyte layers laminated on upper and lower surfaces of the electrode;
first and second sealing sheets bonded to and covering surfaces of the semi-solid electrolyte layers opposite to surfaces of the semi-solid electrolyte layers on which the electrodes are stacked, respectively, and sealing the electrodes and the first and second semi-solid electrolyte layers,
the battery cell having a nonaqueous solution between the electrode mixture layer of the electrode and each of the semisolid electrolyte layers, sealing portions at end edge portions of the first and second sealing sheets,
stacking an electrode having an electrode collector of a second polarity different from the first polarity and electrode mixture layers formed on both upper and lower surfaces thereof on the battery cell sheet,
stacking the battery cells with the first and second sealing sheets peeled off on the second-polarity electrode,
repeating the stacking of the electrode of the second polarity and the battery cell from which the first and second sealing sheets are peeled,
the uppermost battery cell is separated from at least the sealing sheet on the side of the lower stacked surface,
the tab portions of the electrode collectors of the first polarity of the stacked battery cells are welded to each other,
the joint portions of the electrode collectors of the stacked electrodes of the second polarity are welded to each other,
and accommodating the stacked battery cell chip and the second-polarity electrode in a package body such that the tab portion of the first polarity and the tab portion of the second polarity protrude to the outside.
12. The secondary battery according to claim 11,
the propylene carbonate concentration is set to 30.7 wt% or more with respect to the total weight of the entire liquid components contained in the stacked battery cell and the electrode mixture layer of the second polarity electrode.
13. The secondary battery according to claim 11,
the vinylene carbonate concentration is set to be within a range of 2.19-4.00 wt% relative to the total weight of the liquid components contained in the laminated battery unit slice and the electrode mixture layer of the second polarity.
14. A method for manufacturing a secondary battery includes the steps of:
and peeling off at least the upper sealing sheet on the laminated surface side to mount a battery cell, wherein the battery cell comprises: an electrode having an electrode collector of a first polarity and electrode mix layers formed on both upper and lower surfaces thereof; first and second semi-solid electrolyte layers laminated on upper and lower surfaces of the electrode; and first and second sealing sheets bonded to and covering surfaces of the semi-solid electrolyte layers opposite to surfaces on which the electrodes are stacked, respectively, and sealing the electrodes and the first and second semi-solid electrolyte layers, wherein the cell has a nonaqueous solution between an electrode mixture layer of the electrodes and each of the semi-solid electrolyte layers, and sealing portions are provided at end edge portions of the first and second sealing sheets;
stacking an electrode having an electrode collector of a second polarity different from the first polarity and electrode mixture layers formed on upper and lower surfaces thereof on the battery cell sheet;
stacking the battery cells, from which the first and second sealing sheets are peeled, on the second-polarity electrode;
repeating the step of stacking the electrode of the second polarity and the battery cell piece from which the first and second sealing sheets are peeled;
the uppermost battery cell is stacked by peeling off at least the sealing sheet on the lower stacking surface side;
welding tab portions of the electrode collectors of the first polarity of the stacked battery cells to each other;
welding joint portions of electrode collectors of the stacked electrodes of the second polarity to each other; and
and accommodating the stacked battery cell chip and the second-polarity electrode in a package body such that the tab portion of the first polarity and the tab portion of the second polarity protrude to the outside.
15. A manufacturing apparatus of a secondary battery includes:
a peeling unit configured to put a battery cell into a transport unit and peel the sealing sheet from the battery cell by a peeling roller of an adhesive type, wherein the battery cell comprises: an electrode having an electrode collector of a first polarity and electrode mix layers formed on both upper and lower surfaces thereof; first and second semi-solid electrolyte layers laminated on upper and lower surfaces of the electrode; and first and second sealing sheets bonded to and covering surfaces of the semi-solid electrolyte layers opposite to surfaces on which the electrodes are stacked, respectively, and sealing the electrodes and the first and second semi-solid electrolyte layers, wherein the cell has a nonaqueous solution between an electrode mixture layer of the electrodes and each of the semi-solid electrolyte layers, and sealing portions are provided at end edge portions of the first and second sealing sheets; and
and a lamination part which alternately laminates a given plurality of layers of the battery cell from which the sealing sheet is peeled and an electrode having an electrode mixture layer formed on both upper and lower surfaces of an electrode collector of a second polarity different from the first polarity.
Technical Field
The invention relates to a battery cell, a secondary battery, a method for manufacturing the battery cell, and a method for manufacturing the secondary battery.
Background
The electrolyte used in a secondary battery represented by a lithium ion secondary battery is a medium such as: the positive electrode contains ions (for example, lithium ions) corresponding to the object, and has a function of transporting the ions between the positive electrode and the negative electrode and allowing charge and discharge by transferring and receiving electric charges.
In recent years, in order to overcome the drawbacks of the secondary battery such as leakage and evaporation of the electrolyte solution, a sheet-type secondary battery using a polymer electrolyte (solid electrolyte), an electrolyte in which inorganic fine particles are mixed in an ionic liquid to thicken or gel the liquid, and the like have been proposed.
As a background art in this field, there is international publication No. 2007/086518 (patent document 1).
Disclosure of Invention
Problems to be solved by the invention
In recent years, as an electrolyte of a secondary battery, an electrolyte in a semisolid state has been attracting attention. The semisolid electrolyte has a structure in which an electrolyte solution is supported by a skeleton material of an insulating solid having a large specific surface area such as fine particles, and has no fluidity. A secondary battery is formed by providing a sheet-shaped semi-solid electrolyte (hereinafter referred to as a semi-solid electrolyte sheet) between a positive electrode and a negative electrode.
In a semisolid electrolyte sheet, a low viscosity solvent such as propylene carbonate or ethylene carbonate may be added to improve the ionic conductivity. In addition, in order to suppress the reductive decomposition reaction on the surface of the negative electrode of the electrolyte, a negative electrode interface stabilizer such as vinylene carbonate or ethylene fluorocarbon may be added. However, the above-mentioned compounds have high volatility, and in a dry atmosphere which is an environment for manufacturing a battery, the electrolyte composition may change due to volatilization, which may result in a decrease in battery performance.
Further, there is a method of: an electrode laminate in which positive electrodes and negative electrodes are alternately laminated with a semi-solid electrolyte sheet interposed therebetween is formed, and after the electrode laminate is inserted into a package, a highly volatile component is added by injection and sealing is performed.
Accordingly, an object of the present invention is to provide a battery cell and a secondary battery, which can suppress variation in electrolyte composition due to volatilization even when a highly volatile component is used, and which do not cause degradation in battery performance.
Means for solving the problems
In a preferred example of the battery cell of the present invention, there are: an electrode having an electrode collector and electrode mixture layers formed on both upper and lower surfaces thereof; first and second semi-solid electrolyte layers laminated on upper and lower surfaces of the electrode; and first and second sealing sheets bonded to and covering surfaces of the semi-solid electrolyte layers opposite to surfaces on which the electrodes are stacked, respectively, and sealing the electrodes and the first and second semi-solid electrolyte layers, wherein a nonaqueous solution is provided between an electrode mixture layer of the electrodes and the semi-solid electrolyte layers, and sealing portions are provided at end edge portions of the first and second sealing sheets.
In a preferred example of the method for manufacturing a battery cell according to the present invention, the method includes the steps of: coating electrode mixture layers on the upper and lower surfaces of an electrode collector to form electrodes; adding a non-aqueous solution to both sides of the electrode mix layer of the electrode; adding a non-aqueous solution to a semi-solid electrolyte layer while conveying a semi-solid electrolyte sheet composed of a semi-solid electrolyte and a sealing sheet by roll winding; laminating the electrode and the first and second semi-solid electrolyte sheets with a first electrode mix layer on an upper surface side of the electrode and the semi-solid electrolyte layer of a first semi-solid electrolyte sheet provided to the upper surface side of the electrode facing each other, and a second electrode mix layer on a lower surface side of the electrode and the semi-solid electrolyte layer of a second semi-solid electrolyte sheet provided to the lower surface side of the electrode facing each other; severing the first and second semi-solid electrolyte sheets; and forming a sealing portion by heating and pressing an edge portion of a laminate formed by laminating the electrode and the first and second semi-solid electrolyte sheets by a heat-sealing portion.
Further, in a preferred example of the secondary battery of the present invention, the secondary battery is constituted by: the battery cell is mounted by peeling off at least the upper sealing sheet on the laminated surface side, and the battery cell comprises: an electrode having an electrode collector of a first polarity and electrode mix layers formed on both upper and lower surfaces thereof; first and second semi-solid electrolyte layers laminated on upper and lower surfaces of the electrode; and first and second sealing sheets bonded to and covering surfaces of the semi-solid electrolyte layers opposite to surfaces on which the electrodes are stacked, respectively, and sealing the electrodes and the first and second semi-solid electrolyte layers, wherein the cell has a nonaqueous solution between an electrode mixture layer of the electrodes and the semi-solid electrolyte layers, wherein the first and second sealing sheets have sealing portions at end edges thereof, wherein the cell is stacked with electrodes having an electrode collector of a second polarity different from the first polarity and electrode mixture layers formed on upper and lower surfaces thereof, wherein the cell is stacked with the first and second sealing sheets peeled off on the electrode of the second polarity, and wherein the stacking of the electrode of the second polarity and the cell is repeated with the first and second sealing sheets peeled off, the uppermost battery cell is obtained by peeling at least the sealing sheet on the lower lamination surface side, welding the tabs of the first polarity electrode collectors of the laminated battery cells to each other, welding the tabs of the second polarity electrode collectors of the laminated battery cells to each other, and accommodating the laminated battery cells and the second polarity electrode in a package body such that the tabs of the first polarity and the tabs of the second polarity protrude to the outside.
Effects of the invention
According to the present invention, it is possible to provide a battery cell and a secondary battery that do not cause a decrease in battery performance even when a highly volatile component is used.
Drawings
Fig. 1 is a diagram schematically showing a method of manufacturing a battery cell.
Fig. 2A is a top view schematically illustrating a battery cell of example 1.
Fig. 2B is a cross-sectional view a-a' of the battery cell shown in fig. 2A.
Fig. 2C is a B-B' cross-sectional view of the battery cell shown in fig. 2A.
Fig. 2D is a C-C cross-sectional view of the battery cell shown in fig. 2A.
Fig. 3A is a top view schematically illustrating a battery cell of example 2.
Fig. 3B is a cross-sectional view a-a' of the battery cell shown in fig. 3A.
Fig. 3C is a B-B' cross-sectional view of the battery cell shown in fig. 3A.
Fig. 4A is a top view schematically illustrating a battery cell of example 3.
Fig. 4B is a cross-sectional view a-a' of the battery cell shown in fig. 4A.
Fig. 4C is a B-B' cross-sectional view of the battery cell shown in fig. 4A.
Fig. 5 is a view schematically showing a method for manufacturing the electrode laminate.
Fig. 6A is a plan view schematically showing an electrode laminate of example 4.
Fig. 6B is a sectional view a-a' of the electrode laminate shown in fig. 6A.
Fig. 6C is a B-B' sectional view of the electrode stack shown in fig. 6A.
Fig. 6D is a C-C' sectional view of the electrode stack shown in fig. 6A.
Fig. 7 is a plan view schematically showing the laminated secondary battery.
Fig. 8A is a plan view schematically showing an electrode laminate of example 5.
Fig. 8B is a sectional view a-a' of the electrode laminate shown in fig. 8A.
Fig. 8C is a B-B' sectional view of the electrode stack shown in fig. 8A.
Fig. 8D is a C-C' sectional view of the electrode stack shown in fig. 8A.
Fig. 9A is a plan view schematically showing an electrode laminate of example 6.
Fig. 9B is a sectional view a-a' of the electrode laminate shown in fig. 9A.
Fig. 9C is a B-B' sectional view of the electrode stack shown in fig. 9A.
Fig. 9D is a cross-sectional view C-C' of the electrode stack shown in fig. 9A.
Fig. 10 is a graph showing the results of the evaluation of all the cells in the injection process.
Fig. 11 is a graph showing the results of the weight% of propylene carbonate and the initial capacity in the model cell in the positive electrode half cell evaluation experiment in the processes of examples 1 to 6.
Fig. 12 is a graph showing the results of the weight% of propylene carbonate and the initial capacity in the model unit in the negative electrode half cell evaluation experiment in the processes of examples 1 to 6.
Fig. 13 is a graph showing the results of the vinylene carbonate weight% and the initial capacity in the model cell in the negative electrode half cell evaluation experiment in the processes of examples 1 to 6.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings for describing the embodiments, members having the same functions are denoted by the same reference numerals, and redundant description thereof will be omitted. In the embodiments, description of the same or similar parts will not be repeated in principle, except when particularly necessary. Furthermore, in the drawings describing the embodiments, hatching may be omitted in the cross-sectional views for ease of understanding the structure.
[ example 1]
The present embodiment will be described with reference to fig. 1 and 2A to 2D, taking as an example a battery cell that is a constituent element of a laminated secondary battery.
Fig. 1 shows a schematic diagram of a method of manufacturing a
Next, the
After the
Fig. 2A is a plan view schematically showing the
As shown in fig. 2A to 2D, the
The
As shown in fig. 2B, the
As shown in fig. 2C, in the sealing
Further, as shown in fig. 2D, the semi-solid electrolyte layers 9 facing each other are heated and pressurized by the heat-
The
Next, the respective constituent materials and the manufacturing method will be described.
First, the constituent material of the
As the
The
In addition to this, the present invention is,the
Further, the
Next, the constituent materials and the manufacturing method of the
The semi-solid electrolyte sheet is configured to contain an electrolyte, a support material for the electrolyte, and a binder for binding the support materials to each other. The electrolyte is not particularly limited as long as it is a nonaqueous electrolyte. Specifically, as an example of the electrolyte salt, (CF) can be used3SO2)2NLi、(SO2F)2NLi、LiPF6、LiClO4、LiAsF6、LiBF4、LiB(C6H5)4、CH3SO3Li、CF3SO3Li and other Li salts, or mixtures thereof. The solvent of the nonaqueous electrolytic solution is an organic solvent, an ionic liquid, or a substance exhibiting properties similar to those of an ionic liquid in the presence of an electrolyte salt (in this patent, the solvent is a solvent for a nonaqueous electrolytic solution)A substance that exhibits properties similar to those of an ionic liquid in the presence of an electrolyte salt may be simply referred to as an ionic liquid). As an example, tetraethylene glycol dimethyl ether, triethylene glycol dimethyl ether, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-1-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide, ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate, propylene carbonate, diethyl carbonate, 1, 2-dimethoxyethane, 1, 2-diethoxyethane, γ -butyrolactone, tetrahydrofuran, 1, 3-dioxolane, 4-methyl-1, 3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile, and the like, or a mixture thereof can be used.
Particles are used as a carrier material for the electrolyte. Fine particles are desirable because the surface area per unit volume can be increased in order to increase the carrying capacity of the electrolyte. Examples of the material of the fine particles include, but are not limited to, silica, alumina, titania, zirconia, polypropylene, polyethylene, and a mixture thereof.
The binder is not particularly limited as long as it can bind the support material. For example, polyvinyl fluoride, polyvinylidene fluoride (PVDF), polytetrafluoroethylene, a copolymer of vinylidene fluoride and hexafluoropropylene (P (VDF-HFP)), polyimide, styrene-butadiene rubber, or a mixture thereof, or the like can be used.
The electrolyte solution, the support material, and the binder are mixed, and then dispersed as a dispersion medium in, for example, N-methyl-2-pyrrolidone (NMP) to prepare a semi-solid electrolyte slurry. In the above, the semi-solid electrolyte paste is applied to the
Next, the constituent materials and the manufacturing method of the
The
Positive
Examples of the positive electrode active material include, but are not limited to, lithium cobaltate, lithium nickelate, and lithium manganate. Specifically, the positive electrode active material may be a material capable of inserting and releasing lithium into and from a crystal structure, and may be a lithium-containing transition metal oxide into which a sufficient amount of lithium has been previously inserted, and the transition metal may be a single material such as manganese (Mn), nickel (Ni), cobalt (Co), or iron (Fe), or a material containing 2 or more transition metals as a main component. Further, the crystal structure such as a spinel crystal structure or a layered crystal structure is not particularly limited as long as it can insert and extract lithium ions. Further, as the positive electrode active material, a material obtained by substituting a part of transition metal and lithium in the crystal with an element such as Fe, Co, Ni, Cr, Al, or Mg, or a material obtained by doping an element such as Fe, Co, Ni, Cr, Al, or Mg in the crystal may be used.
As the binder, for example, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, or the like can be used.
As the conductive assistant, a carbon material, for example, acetylene black, ketjen black, artificial graphite, carbon nanotube, or the like can be used.
The semi-solid electrolyte can use the same material as in the case of the
The positive electrode active material, the conductive additive, the binder, and the semisolid electrolyte are mixed and dispersed as a dispersion medium in, for example, N-methyl-2-pyrrolidone (NMP) to prepare a positive electrode slurry. The positive electrode slurry was applied to the positive electrode
Next, the constituent materials and the manufacturing method of the
The
Negative
As the negative electrode active material, for example, a crystalline carbon material or an amorphous carbon material can be used. However, the negative electrode active material is not limited to these materials, and for example, natural graphite, various artificial graphite agents, carbon materials such as coke, and the like may be used. The particle shape can be applied to various particle shapes such as a scale shape, a spherical shape, a fibrous shape, and a block shape.
As the binder, for example, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, or the like can be used.
As the conductive assistant, a carbon material, for example, acetylene black, ketjen black, artificial graphite, carbon nanotube, or the like can be used.
The same material as in the case of the
The negative electrode active material, the conductive additive, the binder, and the semisolid electrolyte are mixed, and further dispersed as a dispersion solvent in, for example, N-methyl-2-pyrrolidone (NMP) to prepare a negative electrode slurry. The negative electrode slurry was applied to the negative electrode
According to the present embodiment, since the
[ example 2]
The battery cell of example 2 will be described with reference to fig. 3A to 3C. The same components as those in
In the
According to the present embodiment, as compared with the case where the sealing
[ example 3]
The battery cell of example 3 will be described with reference to fig. 4A to 4C. The same components as those in
The battery cell 12 of the present embodiment is characterized by including the peeling
According to the present embodiment, by forming the peeling
[ example 4]
A method for manufacturing a secondary battery using the battery cell sheet described in example 1 is described as an example of a laminated secondary battery. Hereinafter, an example of a battery cell using a negative electrode is shown.
A
Next, the
Fig. 6A is a plan view schematically showing the
Fig. 6B to 6D show only a part of the electrode stack structure, and the number of stacked electrodes is not particularly limited. Thereafter, the plurality of
According to the present embodiment, by using the
[ example 5]
A method for manufacturing a secondary battery using the battery cell sheet described in example 2 is described with reference to a laminated lithium ion battery as an example. Hereinafter, an example of a battery cell using a negative electrode is shown.
A
Next, the
Fig. 8A is a plan view schematically showing the
According to the present embodiment, compared to the method for manufacturing a secondary battery using the
[ example 6]
A method for manufacturing a secondary battery using the battery cell sheet described in example 3 is described with reference to a laminated lithium ion battery as an example. Hereinafter, an example of a battery cell using a negative electrode is shown.
A battery cell 12 was produced in the same manner as in example 3. In the battery cell 12, by forming the peeling
Fig. 9A is a plan view schematically showing the electrode stack 18. Fig. 9B is a sectional view at the position of the cutting line a-a ' of fig. 9A, fig. 9C is a sectional view at the position of the cutting line B-B ' of fig. 9A, and fig. 9D is a sectional view at the position of the cutting line C-C ' of fig. 9A. Fig. 9B to 9D show only a part of the electrode stack structure, and the number of stacked electrodes is not particularly limited. Thereafter, the same procedure as in example 4 was repeated.
According to the present embodiment, compared to the method for manufacturing a secondary battery using the
[ example 7]
The propylene carbonate that improves the ionic conductivity in the electrolyte and the vinylene carbonate that suppresses the reductive decomposition reaction on the negative electrode surface of the electrolyte are main additives that are relevant to the performance of the secondary batteries disclosed in examples 4 to 6. The inventors of the present application have clarified the appropriate amounts of both additives by making model cells and performing evaluation experiments.
In order to examine the performance of only each of the positive electrode and the negative electrode, half cells of a combination of the positive electrode and Li metal and a combination of the negative electrode and Li metal were prepared with the electrolyte sheet interposed therebetween. All the cells of the combination of the positive electrode and the negative electrode were prepared with the electrolyte sheet interposed therebetween.
As the experimental conditions, evaluation experiments were carried out by reproducing conditions equivalent to the following cases: (1) filling the non-aqueous solution between the electrodes by a liquid injection process; and (2) when the battery cell disclosed in examples 1 to 6 was constructed, the
Method for manufacturing positive electrode in liquid injection process
A method for producing the positive electrode is described. Use of LiNi as a positive electrode active material1/3Co1/3Mn1/3O2Acetylene black is used as a conductive aid, and a vinylidene fluoride-hexafluoropropylene copolymer is used as a binder. The positive electrode active material, the conductive additive, and the binder were mixed in weight percentages of 84, 7, and 9, and dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a positive electrode slurry. The positive electrode slurry was applied to an aluminum foil so that the amount of the solid content applied became 19 mg-cm2And drying for 10 minutes by using a hot air drying furnace at 120 ℃. Subsequently, the positive electrode coating layer was rolled to adjust the density to 2.8g/cm3。
Method for making semi-solid electrolyte sheet in liquid injection process
Methods of making semi-solid electrolyte sheets are described. First, the (CF)3SO2)2NLi and tetraethylene glycol dimethyl ether were mixed at a molar ratio of 1: 1 to prepare an electrolyte. The electrolyte and SiO were placed in a glove box under argon atmosphere2The nanoparticles (particle diameter 7nm) were mixed at a volume fraction of 80: 20, and after adding methanol thereto, the mixture was stirred for 30 minutes using a magnetic stirrer. Then, the resulting mixed solution was spread on a shallow pan, and methanol was distilled to obtain a powdery semisolid electrolyte. To this powder, 5 mass% of PTFE powder was added, and the mixture was spread by pressing while being sufficiently mixed, thereby obtaining a semi-solid electrolyte sheet having a thickness of about 200 μm.
Method for manufacturing negative electrode in liquid injection process
A method for producing a negative electrode is described. Graphite was used as a negative electrode active material, acetylene black was used as a conductive aid, and a vinylidene fluoride-hexafluoropropylene copolymer was used as a binder. The negative electrode active material, the conductive additive, and the binder were mixed so that the weight percentages thereof were 88, 2, and 10, and then dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a negative electrode slurry. The negative electrode slurry was coated on a copper foil so that the coating amount of the solid content became 8.3mg/cm2And drying for 10 minutes by using a hot air drying furnace at 120 ℃. Subsequently, the negative electrode coating layer was rolled to adjust the density to 1.6g/cm3。
Method for evaluating positive electrode half unit in liquid injection process
The initial capacity evaluation was performed by the method shown below. Lithium metal is used in the counter electrode. The positive electrode, the semi-solid electrolyte sheet, and the lithium metal were punched out to have a diameter of 16mm, and laminated such that the semi-solid electrolyte sheet was interposed between the positive electrode and the lithium metal. Then, a non-aqueous solution is injected into the mold to form a mold unit, and the non-aqueous solution is injected into the mold to form a (CF)3SO2)2NLi and tetraethylene glycol dimethyl ether at a molar ratio of 1: 1 was added to an electrolyte solution mixed at a molar ratio of 1 as follows: the low-viscosity solvent Propylene Carbonate (PC) became 42 wt% { here, corresponding to the denominator calculated as 42 wt% (electrolyte weight in the semi-solid electrolyte sheet) + (added nonaqueous solution weight), the denominator being the total weight of the liquid components present in the model cell }, Vinylene Carbonate (VC) as the negative electrode interface stabilizer became 3 wt%, tetrabutylammonium hexafluorophosphate (NBu) as the anticorrosive agent, and4PF6) To a content of 2.5 wt%.
First, constant current charging was performed at 0.05C until the voltage reached 4.2V { here, C, where a battery of a nominal capacity was discharged (charged), and the current value at which the discharge (charge) was completed in 1 hour was regarded as 1C. Used as a general unit in batteries. The 0.05C indicates a current value at which the discharge (charge) was completed in 20 hours. The nominal capacities of the positive electrode half cell, the negative electrode half cell, and the entire cell of the present example were evaluated by using values theoretically calculated based on the amounts of the active materials contained in the positive electrode and the negative electrode, respectively. }
After that, constant-voltage charging was performed at a voltage of 4.2V until the current value became equivalent to 0.005C. Then, the discharge was stopped for 1 hour in the open circuit state, and constant current discharge was performed at 0.05C until the voltage reached 2.7V. The discharge capacity obtained at this time was used as an initial capacity. The initial capacity is converted to a value per weight of the positive electrode active material used.
Evaluation method of negative electrode half cell in liquid injection Process
The initial capacity evaluation was carried out by the method shown below. Lithium metal is used in the counter electrode. The negative electrode, the semi-solid electrolyte sheet, and the lithium metal were punched out to have a diameter of 16mm, and laminated so that the semi-solid electrolyte sheet was interposed between the negative electrode and the lithium metal. Then, a non-aqueous solution is injected into the mold to form a mold unit, and the non-aqueous solution is injected into the mold to form a (CF)3SO2)2NLi and tetraethylene glycol dimethyl ether are mixed in a molar ratio of 1: 1 in the electrolyte and are added as follows: propylene Carbonate (PC) of low viscosity solvent42 wt% of Vinylene Carbonate (VC) serving as a negative electrode interface stabilizer and 3 wt% of tetrabutylammonium hexafluorophosphate (NBu) serving as an anticorrosive4PF6) To a content of 2.5 wt%.
First, constant current charging was performed at 0.05C until the voltage reached 0.005V. After that, constant-voltage charging was performed at a voltage of 0.005V until the current value became equivalent to 0.005C. Then, the discharge was stopped for 1 hour in the open circuit state, and constant current discharge was performed at 0.05C until the voltage reached 1.5V. The discharge capacity obtained at this time was used as an initial capacity. The initial capacity is converted to a value per weight of the negative electrode active material used.
Method for evaluating whole unit in liquid injection process
The initial capacity evaluation was carried out by the method shown below. The positive electrode and the semi-solid electrolyte sheet were punched to be 16mm in diameter, the negative electrode was punched to be 18mm in diameter, and lamination was performed so that the semi-solid electrolyte sheet was interposed between the positive electrode and the negative electrode. Then, a non-aqueous solution is injected into the mold to form a mold unit, and the non-aqueous solution is injected into the mold to form a (CF)3SO2)2NLi and tetraethylene glycol dimethyl ether are mixed in a molar ratio of 1: 1 in the electrolyte and are added as follows: propylene Carbonate (PC) as a low-viscosity solvent was 42 wt%, Vinylene Carbonate (VC) as a negative electrode interface stabilizer was 3 wt%, and tetrabutylammonium hexafluorophosphate (NBu) as an anticorrosive agent was added4PF6) To a content of 2.5 wt%.
First, constant current charging was performed at 0.05C until the voltage reached 4.2V. After that, constant-voltage charging was performed at a voltage of 4.2V until the current value became equivalent to 0.005C. Then, the discharge was stopped for 1 hour in the open circuit state, and constant current discharge was performed at 0.05C until the voltage reached 2.7V. The discharge capacity obtained at this time was used as an initial capacity. The initial capacity is converted to a value per weight of positive electrode used.
Fig. 10 shows the results of the all-cell evaluation in the 5-time injection process performed under the same conditions. The initial capacities were 121.4, 122.6, 132.6, 134.3, 126.8mAh/g with experimental variation of + -5%.
Method for manufacturing positive electrode in Processes of examples 1 to 6
A method for producing the positive electrode is described. Use of LiNi as a positive electrode active material1/3Co1/3Mn1/3O2Acetylene black is used as a conductive aid, a vinylidene fluoride-hexafluoropropylene copolymer is used as a binder, and (CF) is used as an electrolyte3SO2)2NLi and tetraethylene glycol dimethyl ether at a molar ratio of 1: 1 molar ratio of the electrolyte solution. The positive electrode active material, the conductive additive, the binder, and the electrolyte were mixed so that the weight percentages were 74, 6, 8, and 12, and further dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a positive electrode slurry. The positive electrode slurry was coated on an aluminum foil so that the amount of solid matter coated became 19mg/cm2And drying for 10 minutes by using a hot air drying furnace at 100 ℃. Subsequently, the positive electrode coating layer was rolled to adjust the density to 2.8g/em3。
Methods for producing semi-solid electrolyte sheets in the Processes of examples 1 to 6
Methods of making semi-solid electrolyte sheets are described. First, the (CF)3SO2)2NLi and tetraethylene glycol dimethyl ether in a molar ratio of 1: 1, and mixing to prepare an electrolyte. In a glove box under argon atmosphere, the electrolyte and SiO2Nanoparticles (particle diameter 7nm) were measured in volume fraction 80: 20, and after adding methanol thereto, stirred for 30 minutes using a magnetic stirrer. Then, the resulting mixed solution was spread on a shallow pan, and methanol was distilled to obtain a powdery semisolid electrolyte. To this powder, 5 mass% of PTFE powder was added, and the mixture was spread by pressing while being sufficiently mixed, thereby obtaining a semi-solid electrolyte sheet having a thickness of about 200 μm.
Method for manufacturing negative electrode in Processes of examples 1 to 6
A method for producing a negative electrode is described. Graphite is used as a negative electrode active material, (acetylene black) is used as a conductive aid, (vinylidene fluoride-hexafluoropropylene copolymer is used as a binder, and (CF) is used as an electrolyte3SO2)2NLi and tetraethylene glycolDimethyl ether was mixed at a molar ratio of 1: 1 to obtain an electrolyte. The negative electrode active material, the conductive assistant, the binder, and the electrolyte were mixed so that the weight percentages of the negative electrode active material, the conductive assistant, the binder, and the electrolyte became 77, 2, 9, and 12, and the resulting mixture was dispersed in N-methyl-2-pyrrolidone (NMP), thereby preparing a negative electrode slurry. The negative electrode slurry was coated on a copper foil so that the amount of solid matter coated became 8.3mg/cm2And drying for 10 minutes in a hot air drying furnace at 100 ℃. Subsequently, the negative electrode coating layer was rolled to adjust the density to 1.7g/cm3。
Method for evaluating positive electrode half cell in the Processes of examples 1 to 6
The initial capacity evaluation was performed by the method shown below. Lithium metal is used in the counter electrode. The positive electrode, the semi-solid electrolyte sheet, and the lithium metal were punched to a diameter of 16 mm. Then, the mixture will contain 0-29.6 wt% (CF)3SO2)2NLi, 0 to 22.9 wt% of tetraethylene glycol dimethyl ether, 42 to 88.4 wt% of propylene carbonate, 3 to 6.3 wt% of vinylene carbonate and 2.5 to 5.3 wt% of tetrabutylammonium hexafluorophosphate in a nonaqueous solution were added (dropped and applied) to the positive electrode so that the weight% of propylene carbonate in the model cell reached 12.5 to 42 wt% { here, the denominator when the weight% of propylene carbonate was calculated was (electrolyte weight in the electrode) + (electrolyte weight in the semisolid electrolyte sheet) + (added nonaqueous solution weight), and the total weight of the liquid components present in the model cell was taken as the denominator }. Next, a mold unit was fabricated by laminating so that the semisolid electrolyte layer was interposed between the positive electrode and the lithium metal.
First, constant current charging was performed at 0.05C until the voltage reached 4.2V. After that, constant-voltage charging was performed at a voltage of 4.2V until the current value became equivalent to 0.005C. Then, the discharge was stopped for 1 hour in the open circuit state, and constant current discharge was performed at 0.05C until the voltage reached 2.7V. The discharge capacity obtained at this time was used as an initial capacity. The initial capacity is converted to a value per weight of the positive electrode active material used.
Fig. 11 shows the results of the weight% of propylene carbonate and the initial capacity in the model cell in the positive electrode half cell evaluation experiment in the processes of examples 1 to 6. The propylene carbonate concentration is 17.5 wt% or more, which indicates a capacity equal to or higher than that of the injection process within ± 5% of the evaluation result in the injection process.
Method for evaluating negative electrode half cell in Processes of examples 1 to 6
The initial capacity evaluation was carried out by the following method. Lithium metal is used in the counter electrode. The negative electrode, the semi-solid electrolyte sheet, and the lithium metal were punched out to a diameter of 16 mm. Then, the mixture will contain 0-29.6 wt% (CF)3SO2)2NLi, 0 to 22.9 wt% of tetraethylene glycol dimethyl ether, 42 to 89.5 wt% of propylene carbonate, 2.1 to 10.6 wt% of vinylene carbonate and 0 to 5.3 wt% of tetrabutylammonium hexafluorophosphate in a nonaqueous solution are added (dropped and applied) to the negative electrode so that the weight% of propylene carbonate in the model cell becomes 22.5 to 54.4 wt% { where the denominator when the weight% of propylene carbonate is calculated is (electrolyte weight in the electrode) + (electrolyte weight in the semisolid electrolyte sheet) + (nonaqueous solution weight to be added) }, the weight of the entire liquid component present in the model cell is taken as the denominator }, and the weight of vinylene carbonate becomes 1 to 5 wt% { where the denominator when the weight% of vinylene carbonate is calculated is (weight in the electrode) + (electrolyte weight in the semisolid electrolyte sheet) + (nonaqueous solution weight to be added), the weight of the entire liquid component present in the model cell is taken as the denominator }. Next, a mold cell was fabricated by laminating so that a semi-solid electrolyte sheet was interposed between the negative electrode and the lithium metal.
First, constant current charging was performed at 0.05C until the voltage reached 0.005V. After that, constant-voltage charging was performed at a voltage of 0.005V until the current value became equivalent to 0.005C. Then, the discharge was stopped for 1 hour in the open circuit state, and constant current discharge was performed at 0.05C until the voltage reached 1.5V. The discharge capacity obtained at this time was used as an initial capacity. The initial capacity is converted to a value per weight of the negative electrode used.
Fig. 12 shows the results of the weight% of propylene carbonate and the initial capacity in the model unit in the negative electrode half-cell evaluation experiment in the processes of examples 1 to 6. The propylene carbonate concentration is 30.7 wt% or more, which indicates a capacity equal to or higher than that of the injection process within ± 5% of the evaluation result in the injection process.
Fig. 13 shows the results of the vinylene carbonate weight% and the initial capacity in the model cell in the negative electrode half cell evaluation experiment in the processes of example 1 to example 6. The vinylene carbonate concentration is in the range of 2.19-4.00 wt% and the content is equal to or more than the capacity of the injection process within + -5% of the evaluation result in the injection process.
Method for evaluating all units in Processes of examples 1 to 6
The initial capacity evaluation was carried out by the method shown below. The positive electrode and the semi-solid electrolyte sheet were cut to a diameter of 16mm, and the negative electrode was cut to a diameter of 18 mm. Then, a nonaqueous solution containing 88.4 wt% of propylene carbonate, 6.3 wt% of vinylene carbonate, and 5.3 wt% of tetrabutylammonium hexafluorophosphate was added (dropped and applied) to the negative electrode and the semisolid electrolyte sheet so that the wt% of propylene carbonate in the model cell became 41.3 and 54.4 wt% { here, the denominator when the wt% of propylene carbonate was calculated was (electrolyte weight in the electrode) + (electrolyte weight in the semisolid electrolyte sheet) + (nonaqueous solution weight added), the weight of the entire liquid component present in the model cell was taken as the denominator }, and the vinylene carbonate became 2.9 and 4 wt% { here, the denominator when the wt% of vinylene carbonate was calculated was (electrolyte weight in the electrode) + (electrolyte weight in the semisolid electrolyte sheet) + (nonaqueous solution weight added), the weight of the entire liquid component present in the model cell is taken as the denominator }. Next, the mold unit was fabricated by laminating the layers so that the semi-solid electrolyte layer was interposed between the positive electrode and the negative electrode.
First, constant current charging was performed at 0.05C until the voltage reached 4.2V. After that, constant-voltage charging was performed at a voltage of 4.2V until the current value became equivalent to 0.005C. Then, the discharge was stopped for 1 hour in the open circuit state, and constant current discharge was performed at 0.05C until the voltage reached 2.7V. The discharge capacity obtained at this time was used as an initial capacity. The initial capacity is converted to a value per weight of positive electrode used.
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