JP2004193006A - Manufacturing method of layer-built cell, battery pack, and vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a laminated cell capable of preventing a liquid junction between unit cell layers even when the laminated cell is composed by stacking a plurality of unit cell layers by using a polymer gel electrolyte. <P>SOLUTION: In the manufacturing method of the laminated cell, a plurality of sheet-like electrodes 10 are first manufactured (step S1). Next, the electrodes are stacked by interposing gel electrode layers 4 between the electrodes (step S2); a side face of an electrode layered product 30 formed by stacking the electrodes is fitted in a die 40 matching to the side face of the layered product 30 (step S3); and a molten resin is injected into the die 40 (step S4). After the resin is hardened (step S5), the die 40 is removed (step S6). The similar processes are repeated for all the four side faces of the layered product 30 (step S7, S4-S6). Since the resin 60 is provided for all the side faces of the layered product 30, the hardened resin plays a role of a sealing member for preventing any leakage of the gel electrolyte. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a stacked battery, and more particularly to a method for manufacturing a stacked battery using a gel electrolyte as an electrolyte.
[0002]
[Prior art]
Lithium secondary batteries include those using a solid electrolyte, those using a liquid electrolyte, and those using a polymer gel electrolyte as the electrolyte sealed therein.
[0003]
An all solid polymer electrolyte such as polyethylene oxide is used for the solid electrolyte, while a 100% electrolyte is used for the liquid electrolyte. The polymer gel electrolyte can be said to be in the middle of these, for example, polyvinylidene fluoride (PVDF) itself, in which the electrolyte is held in a polymer skeleton having no lithium ion conductivity ( For example, see Patent Document 1.)
[0004]
[Patent Document 1]
JP-A-11-204136 [0005]
[Problems to be solved by the invention]
When a single cell layer is formed using this polymer gel electrolyte, and a plurality of the single cell layers are stacked to produce a bipolar battery, the electrolyte seeps out between each single cell layer and comes into contact with the electrolyte of another single cell layer. As a result, there is a problem that a short circuit between the unit cell layers called a liquid junction occurs.
[0006]
Therefore, an object of the present invention is to provide a method of manufacturing a laminated battery that can prevent a liquid junction between the unit cell layers even when a laminated battery is configured by laminating a plurality of unit cells using a polymer gel electrolyte. That is.
[0007]
[Means for Solving the Problems]
The method for manufacturing a laminated battery according to the present invention includes laminating a gel electrolyte layer between a plurality of sheet-like electrodes, and forming a side surface of the laminated electrode laminate into a mold having a notch matching the side surface. The sealing member is inserted and molten resin is injected into the mold, and the resin is cured to prevent leakage of the gel electrolyte.
[0008]
Another method for producing a laminated battery according to the present invention is a water tank in which a gel electrolyte layer is sandwiched between a plurality of sheet-like electrodes, and a side surface of the laminated electrode laminate is filled with a molten resin. After being immersed, the resin adhered to the electrode laminate is cured to form a sealing member for preventing leakage of the gel electrolyte.
[0009]
【The invention's effect】
In the method for manufacturing a laminated battery according to the present invention, a mold is fitted into the side surface of the electrode laminate, a resin is injected into the mold and cured, and this is performed on all side surfaces of the electrode laminate. Therefore, the cured resin plays a role of a sealing member for preventing the leakage of the gel electrolyte, so that a liquid junction due to the leakage of the gel electrolyte can be prevented. Further, the laminated battery made by the method of the present invention can prevent the invasion of moisture from the outside by the resin, and can improve the rigidity.
[0010]
In another method for manufacturing a laminated battery of the present invention, the side surface of the electrode laminate is immersed in a water tank filled with a molten resin, taken out, and the cured resin is provided on the entire side surface of the electrode laminate. Therefore, the cured resin plays a role of a sealing member for preventing the leakage of the gel electrolyte, so that a liquid junction due to the leakage of the gel electrolyte can be prevented. Further, the laminated battery made by the method of the present invention can prevent the invasion of moisture from the outside by the resin, and can improve the rigidity.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, some constituent elements are exaggerated for clarity of description.
[0012]
(First Embodiment)
A first aspect of the present invention is to stack a gel electrolyte layer between a plurality of sheet-like electrodes, and to insert the side surface of the electrode stack formed by lamination into a mold having a notch matching the side surface, This is a method for manufacturing a laminated battery in which a molten resin is injected into the mold and the resin is cured to form a sealing member for preventing leakage of the gel electrolyte.
[0013]
In the following, a case where the stacked battery is a bipolar battery will be specifically described. However, the present invention is not limited to this, and the present invention can be applied to any stacked battery.
[0014]
FIG. 1 is a flowchart showing a manufacturing procedure of the bipolar battery of the present invention, FIG. 2 is a cross-sectional view showing electrodes of the bipolar battery, FIG. 3 is a cross-sectional view showing how electrodes are stacked with a gel electrolyte layer interposed therebetween, and FIG. FIG. 5 is a perspective view showing a state in which a mold is fitted to the laminate, FIG. 5 is a sectional view showing a state in which the mold is fitted in the electrode laminate, and FIG. 6 is a sectional view showing a state of the electrode laminate after removing the mold. .
[0015]
Hereinafter, while describing each procedure of the flowchart shown in FIG. 1, the state of the bipolar battery during the procedure will be described at the same time.
[0016]
As a manufacturing procedure of the bipolar battery, first, the bipolar electrode 10 is manufactured (Step S1). As shown in FIG. 2, the bipolar electrode 10 is manufactured by disposing the positive electrode active material layer 2 on one surface of the current collector 1 and disposing the negative electrode active material layer 3 on the other surface. In other words, the bipolar electrode 10 is manufactured by laminating the positive electrode active material layer 2, the current collector 1, and the negative electrode active material layer 3 in this order.
[0017]
Next, the produced bipolar electrode 10 is laminated with the gel electrolyte layer 4 (step S2). Here, as shown in FIG. 3, the bipolar electrodes 10 are all arranged in the same lamination order, and are laminated with the gel electrolyte layer 4 interposed therebetween. By providing the gel electrolyte layer 4 between the positive electrode active material layer 2 and the negative electrode active material layer 3, ion conduction becomes smooth, and the output of the entire bipolar battery can be improved.
[0018]
The gel electrolyte used for the gel electrolyte layer 4 is, for example, a gel electrolyte in which an electrolyte solution of about several to 98% by weight is held in a polymer skeleton. Particularly, in the bipolar battery of the present invention, 70% by weight or more of the electrolyte solution is used. This is effective when the retained gel electrolyte is used. Note that a layer including the negative electrode active material layer 3, the gel electrolyte layer 4, and the positive electrode active material layer 2 sandwiched between the current collectors 1 is referred to as a unit cell layer 20, and the bipolar electrode 10 and the gel electrolyte layer 4 are laminated. The resulting structure is referred to as an electrode laminate 30.
[0019]
Next, the side surface of the electrode stack 30 is fitted into a mold (step S3). As shown in FIG. 4, the mold 40 is formed in a U-shaped cross section having a notch substantially matching the width of the electrode stack 30, and has an upper surface opened and a lower surface closed. When the mold 40 is inserted into the side surface of the electrode stack 30, a space is formed around the current collector 1 as shown in FIG.
[0020]
Then, as shown in FIG. 5, a molten liquid resin is poured from the upper surface of the mold 40 (step S4). Since the lower surface of the mold 40 is closed, the poured resin accumulates from the bottom of the mold 40. The resin is stored up to a substantially upper surface of the mold 40. The resin only needs to have insulating properties, and examples thereof include silicone, epoxy, urethane, polybutadiene, polypropylene, polyethylene, and paraffin wax.
[0021]
An operator determines whether the resin has cooled and solidified in the mold 40 (step S5). If the resin is not solidified (step S5: NO), the process waits until the resin is solidified. If the resin has solidified (step S5: YES), the mold 40 is removed from the electrode laminate 30 (step S6). The electrode laminate 30 from which the mold 40 has been removed is in a state in which the resin 60 is attached to the outer periphery of the electrode laminate 30 as shown in FIG.
[0022]
Thereafter, it is determined whether the resin has been supplied to all side surfaces of the electrode stack 30 (step S7). As shown in FIG. 4, when the mold 40 is fitted from both side surfaces of the electrode laminate 30, it is necessary to supply the resin to the remaining two side surfaces.
[0023]
If the resin has not been supplied to all the side surfaces (step S7: NO), the process returns to step S4, and the resin is supplied to the remaining side surfaces. When the resin has been supplied to all the side surfaces (step S7: YES), the resin is supplied to all the side surfaces of the electrode stack 30 and the gel electrolyte of the gel electrolyte layer 4 does not leak, so that the bipolar battery Is completed as the completion of the above.
[0024]
As described above, in the manufacturing method of the bipolar battery of the present invention, the resin 60 is provided on the side surface of the electrode laminate 30 by fitting the electrode laminate 30 into the mold 40 and allowing the resin to flow into the mold 40 to solidify. It can serve as a sealing member. Therefore, leakage of the gel electrolyte of the completed bipolar battery can be prevented, and a short circuit due to leakage of the gel electrolyte can be prevented. In addition, intrusion of moisture from the outside can be prevented, and in addition, the rigidity of the bipolar battery can be improved.
[0025]
As a resin material, a material having relatively high durability when solidified, such as silicon, epoxy, urethane, polybutadiene, polypropylene, polyethylene, and paraffin wax, is used, so that the durability of the seal by the resin 60 can be improved. .
[0026]
In the first embodiment, the resin is simply poured into the mold 40 to be solidified. However, the present invention is not limited to this. It is desirable that the resin provided as the seal member sufficiently fills the gap between the current collectors 1 of the bipolar battery and has a minimum amount. This is because, as the amount of the resin increases, the volume and the weight of the resin increase, and the bipolar battery is not required to be downsized. In order to minimize the amount of resin, it is desirable that the shape of the notch of the mold 40 match the thickness of the electrode stack 30 and that the amount of the electrode stack 30 inserted into the mold 40 be as small as possible.
[0027]
In the first embodiment, the resin is provided on the side surface of the electrode stack 30 including the bipolar electrode 10 and the gel electrolyte layer 4. However, when the electrode stack 30 is stacked, the resin is provided on the current collector 1. An insulating layer may be stacked. FIG. 7 is a partial cross-sectional view of a bipolar battery in which an insulating layer is stacked on current collector 1.
[0028]
For example, when the insulating layer 5 is provided on the positive electrode active material layer 2 and the resin 60 is supplied to the side surface of the electrode laminate 30 in this state as described above, the gap between the current collectors 1 is increased as shown in FIG. Is provided with a resin 60 and an insulating layer 5. Thereby, the insulation between the current collectors 1 can be improved, and a short circuit can be more reliably prevented. In the method of the first embodiment, some extra resin 60 is also supplied to the outer periphery of the electrode stack 30. However, in FIG. 7, the extra resin 60 is omitted for the sake of explanation. .
[0029]
(Second embodiment)
In the second aspect of the present invention, the gel electrolyte layer is sandwiched between a plurality of sheet-like electrodes, and the side surface of the electrode laminate obtained by the lamination is immersed in a water tank filled with molten resin and then taken out. And a method for manufacturing a laminated battery in which the resin adhered to the electrode laminate is cured to form a sealing member for preventing leakage of a gel electrolyte.
[0030]
FIG. 8 is a flowchart showing a manufacturing procedure of the bipolar battery of the present invention, and FIG. 9 is a view showing a state of a manufacturing process of the bipolar battery.
[0031]
Hereinafter, the state of the bipolar battery during the procedure will be described while describing each procedure of the flowchart illustrated in FIG.
[0032]
As a manufacturing procedure of the bipolar battery according to the second embodiment, a bipolar electrode 10 is manufactured (step S11), and the gel electrolyte layer 4 is sandwiched between the bipolar electrodes 10 (step S12). The processing of steps S11 and S12 is the same as the processing of steps S1 and S2 of the first embodiment, and a specific description will be omitted.
[0033]
Next, one side surface of the electrode laminate 30 is immersed in a water tank filled with the molten resin (Step S13). Here, as shown in FIG. 9A, one side surface of the electrode stack 30 is set to the lower side. In addition, as shown in FIG. 9B, a water tank filled with a resin that has been heated and melted is prepared in advance. Then, the end portion of one side surface of the electrode laminate 30 is immersed in a water tank and then taken out. Then, as shown in FIG. 9C, the resin adheres to the side surfaces of the electrode stack 30, specifically, between the current collectors 1 and the periphery thereof. This is due to the viscosity of the resin itself.
[0034]
Then, in the state shown in FIG. 9 (c), it is left for a while, and it is determined whether or not the resin is cured (step S14). If the resin is not cured (step S14: NO), the process waits until the resin is cured.
[0035]
As shown in FIG. 9D, when the resin is cured (Step S14: YES), it is determined whether the resin is supplied to all side surfaces of the electrode stack 30 (Step S15).
[0036]
If the resin has not been supplied to all the side surfaces (step S15: NO), the process returns to step S13 to supply the resin to the other side surface, and the unprocessed side surface is immersed in the water tank. When the supply of the resin has been completed for all the side surfaces (Step S15: YES), the resin is supplied to all the side surfaces of the electrode stack 30, and the gel electrolyte of the gel electrolyte layer 4 does not leak. Is completed as the completion of the above.
[0037]
As described above, the resin coating can also be applied to the side surfaces of the electrode stack 30 in the same manner as in the first embodiment, by the method for manufacturing a bipolar battery according to the second embodiment. As a result, in the completed bipolar battery, the gel electrolyte does not leak, and a short circuit that occurs when the gel electrolyte oozes out and comes into contact with another gel electrolyte layer can be prevented. In addition, intrusion of moisture from the outside can be prevented, and in addition, the rigidity of the bipolar battery can be improved.
[0038]
In the above procedure, one side surface of the electrode laminate 30 is immersed in a water tank to wait for curing, and then the next side surface is immersed in a water tank, so that processing is performed for each side surface. However, the procedure may be changed to a procedure in which each side is immersed in a water tank in order, and after all the sides are immersed in the water tank, curing is waited for all sides to be cured.
[0039]
Further, as described in the first embodiment, an insulating layer is provided in advance on the current collector 1 when the electrode laminate 30 is laminated, and is coated with a resin by the above-described method, so that the insulating property shown in FIG. An improved bipolar battery can be obtained.
[0040]
Hereinafter, a current collector, a positive electrode, a negative electrode, a gel electrolyte, a battery case, and the like that can be used for the bipolar batteries manufactured according to the first and second embodiments will be described.
[0041]
[Current collector]
Since the current collector can be formed by laminating and forming any shape by a thin film manufacturing technique such as spray coating on the manufacturing method, for example, aluminum, copper, titanium, nickel, stainless steel ( SUS) and a metal powder such as an alloy thereof as a main component, which is formed by heating a current collector metal paste containing a binder (resin) and a solvent, and formed by the metal powder and the binder. It is. In addition, these metal powders may be used alone or as a mixture of two or more types. Further, different types of metal powders are laminated in multiple layers by taking advantage of the characteristics of the production method. It may be something.
[0042]
The binder is not particularly limited. For example, a conventionally known resin binder material such as an epoxy resin may be used, and a conductive polymer material may be used.
[0043]
The thickness of the current collector is not particularly limited, but is usually about 1 to 100 μm.
[0044]
[Positive electrode active material layer]
The positive electrode contains a positive electrode active material. In addition, an electrolyte, a lithium salt, or the like may be included to increase ionic conductivity. In addition, other than the above, a conductive auxiliary agent for enhancing electron conductivity, NMP (N-methyl-2-pyrrolidone) as a solvent for adjusting slurry viscosity, AIBN (azobisisobutyronitrile) as a polymerization initiator, and the like. May be included. In particular, it is desirable that at least one of the positive electrode and the negative electrode contains an electrolyte, preferably a solid polymer electrolyte, but it is preferable that both are contained in order to further improve the battery characteristics of the bipolar battery.
[0045]
As the positive electrode active material, a composite oxide of a transition metal and lithium, which is also used in a solution-based lithium ion battery, can be used. Specifically, Li · Co-based composite oxide such as LiCoO _2, Li · Ni-based composite oxide such as LiNiO _2, Li · Mn-based composite oxide such as spinel LiMn ₂ O _4, Li · such LiFeO ₂ Fe-based composite oxides and the like can be mentioned. In addition, transition metal and lithium phosphate compounds and sulfate compounds such as LiFePO ₄ ; transition metal oxides and sulfides such as V ₂ O ₅ , MnO ₂ , TiS ₂ , MoS ₂ and MoO ₃ ; PbO ₂ , AgO, NiOOH and the like.
[0046]
The particle size of the positive electrode active material may be any as long as the positive electrode material can be formed into a paste and spray-coated to form a film. Further, in order to reduce the electrode resistance of the bipolar battery, it is preferable to use one having a smaller particle size than that generally used in a solution type lithium ion battery in which the electrolyte is not solid. Specifically, the average particle size of the positive electrode active material is preferably 10 to 0.1 μm.
[0047]
As the electrolyte contained in the positive electrode, a solid polymer electrolyte, a polymer gel electrolyte, a laminate of these, and the like can be used. That is, the positive electrode may have a multilayer structure, and the current collector side and the electrolyte side form a layer in which the type of the electrolyte constituting the positive electrode, the type and the particle size of the active material, and the mixing ratio thereof are changed. You can also.
[0048]
The polymer gel electrolyte is a solid polymer electrolyte having ion conductivity containing an electrolyte solution usually used in lithium ion batteries, and further contains a polymer skeleton having no lithium ion conductivity. And those holding similar electrolytes.
[0049]
Here, the electrolyte solution (electrolyte salt and plasticizer) contained in the polymer gel electrolyte may be any one that is usually used in a lithium ion battery. For example, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiTaF ₆ , inorganic acid anion salts such as LiAlCl ₄ and Li ₂ B ₁₀ Cl ₁₀ and organic acid anions such as LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N and Li (C ₂ F ₅ SO ₂ ) ₂ N. At least one lithium salt (electrolyte salt) selected from ionic salts, and cyclic carbonates such as propylene carbonate and ethylene carbonate; chain carbonates such as dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate; tetrahydrofuran; 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane Ethers such as 1,2-dibutoxyethane; lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; An organic solvent (plasticizer) such as an aprotic solvent or a mixture of at least one selected from two or more can be used. However, it is not limited to these.
[0050]
Examples of the polymer having no lithium ion conductivity used for the polymer gel electrolyte include polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA). it can. However, it is not limited to these. Since PAN, PMMA, and the like fall into the category of having little ionic conductivity, they can be the above-mentioned polymers having ionic conductivity, but are used here as polymer gel electrolytes. This is exemplified as a polymer having no lithium ion conductivity.
[0051]
As the lithium salt, for _{example, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiTaF 6, LiAlCl 4, Li 2 B 10 Cl 10 and the like inorganic acid anion _{salts, Li (CF 3 SO 2)} 2 N, Organic acid anion salts such as Li (C ₂ F ₅ SO ₂ ) ₂ N or a mixture thereof can be used. However, it is not limited to these.
[0052]
Examples of the conductive assistant include acetylene black, carbon black, and graphite. However, it is not limited to these.
[0053]
The amounts of the positive electrode active material, the electrolyte (preferably a solid polymer electrolyte), the lithium salt, and the conductive additive in the positive electrode are determined in consideration of the purpose of use of the battery (e.g., emphasis on output and energy) and ion conductivity. Should. For example, if the amount of the electrolyte, particularly the solid polymer electrolyte, in the positive electrode is too small, the ionic conduction resistance and the ionic diffusion resistance in the active material layer increase, and the battery performance is reduced. On the other hand, if the amount of the electrolyte, particularly the solid polymer electrolyte, in the positive electrode is too large, the energy density of the battery decreases. Therefore, a solid polymer electrolyte mass that meets the purpose is determined in consideration of these factors.
[0054]
The thickness of the positive electrode is not particularly limited, and should be determined in consideration of the intended use of the battery (e.g., emphasis on output, energy, etc.) and ion conductivity, as described for the blending amount. The thickness of a general positive electrode active material layer is about 10 to 500 μm.
[0055]
[Negative electrode active material layer]
The negative electrode includes a negative electrode active material. In addition, an electrolyte, a lithium salt, a conductive additive, and the like may be included in order to increase ion conductivity. Except for the type of the negative electrode active material, the content is basically the same as that described in the section of “Positive electrode active material layer”, and thus the description is omitted here.
[0056]
As the negative electrode active material, a negative electrode active material used in a solution-type lithium ion battery can be used. For example, metal oxide, lithium-metal composite oxide metal, carbon and the like are preferable. More preferred are carbon, transition metal oxide, and lithium-transition metal composite oxide. More preferred are titanium oxide, lithium-titanium composite oxide, and carbon. These may be used alone or in combination of two or more.
[0057]
[Electrolytes]
The electrolyte is a polymer gel electrolyte. The electrolyte may have a multilayer structure, and a layer in which the type of electrolyte and the compounding ratio are changed between the positive electrode side and the negative electrode side may be formed. When a polymer gel electrolyte is used, the ratio (mass ratio) between the polymer constituting the polymer gel electrolyte and the electrolyte is in a range where the ratio of the electrolyte is relatively large, from 20:80 to 2:98.
[0058]
As such a polymer gel electrolyte, a solid polymer electrolyte having ion conductivity and an electrolyte solution usually used in a lithium ion battery are included. However, a high polymer gel electrolyte having no lithium ion conductivity is used. The one in which the same electrolytic solution is held in the skeleton of the molecule is also included. These are the same as the polymer gel electrolyte described as one of the electrolytes included in the [positive electrode], and thus description thereof will be omitted.
[0059]
These solid polymer electrolytes or polymer gel electrolytes may be included in the positive electrode and / or the negative electrode as described above, in addition to the polymer electrolyte constituting the battery, but depending on the polymer electrolyte, the positive electrode, and the negative electrode constituting the battery. Different polymer electrolytes may be used, the same polymer electrolyte may be used, or different polymer electrolytes may be used for different layers.
[0060]
The thickness of the electrolyte constituting the battery is not particularly limited. However, in order to obtain a compact bipolar battery, it is preferable to make the battery as thin as possible as long as the function as an electrolyte can be secured. The thickness of a general solid polymer electrolyte layer is about 10 to 100 μm. However, the shape of the electrolyte can be easily formed so as to cover the upper surface and the outer peripheral portion of the side surface of the electrode (positive electrode or negative electrode) by taking advantage of the characteristics of the manufacturing method. It is not always necessary to have a substantially constant thickness.
[0061]
[Battery exterior material (battery case)]
In order to prevent external impact and environmental degradation, the bipolar battery uses the entire battery stack, including the bipolar battery body template, in order to prevent external impact and environmental degradation during use. It may be housed in an exterior material or a battery case (not shown).
[0062]
From the viewpoint of weight reduction, a conventionally known battery package such as a polymer-metal composite laminate film or an aluminum laminate pack in which a metal (including an alloy) such as aluminum, stainless steel, nickel, or copper is coated with an insulator such as a polypropylene film. It is preferable that the battery laminate is housed and sealed by using a material and joining a part or all of its peripheral portion by heat fusion.
[0063]
In this case, the positive electrode and the negative electrode lead may have a structure sandwiched between the heat-sealed portions and exposed to the outside of the battery exterior material. In addition, the use of a polymer-metal composite laminate film or aluminum laminate pack with excellent thermal conductivity allows the heat to be efficiently transmitted from the heat source of the vehicle and quickly heats the inside of the battery to the battery operating temperature. preferable.
[0064]
[Positive and negative terminal plates]
The positive and negative electrode terminal plates have a function as terminals, and it is better to be as thin as possible from the viewpoint of thinning, but the electrodes, electrolytes and current collectors formed by film formation all have low mechanical strength. Therefore, it is desirable to have sufficient strength to sandwich and support them from both sides. Further, from the viewpoint of suppressing the internal resistance at the terminal portion, it can be said that the thickness of the positive electrode and negative electrode terminal plates is usually preferably about 0.1 to 2 mm.
[0065]
As the material of the positive electrode terminal and the negative electrode terminal plate, a material usually used in a lithium ion battery can be used. For example, aluminum, copper, titanium, nickel, stainless steel (SUS), alloys thereof, and the like can be used. It is preferable to use aluminum from the viewpoints of corrosion resistance, ease of production, economy, and the like.
[0066]
The materials of the positive electrode terminal plate and the negative electrode terminal plate may be the same or different. Further, these positive and negative electrode terminal plates may be formed by laminating different materials from each other in multiple layers.
[0067]
When the shape of the positive electrode and the negative electrode terminal plate is also used as a template, the terminal plate is provided in a shape obtained by tracing the outer surface of a heat source of an automobile or the like, and in the terminal plate provided at a position opposite to the template, the terminal plate is provided. Any shape may be used as long as the outer surface of the current collector is traced, and may be formed by tracing by press molding or the like. In the terminal plate provided at a position opposite to the template, the terminal plate may be formed by spray coating similarly to the current collector.
[0068]
[Positive and negative electrode leads]
As the positive and negative electrode leads, known leads that are usually used in lithium ion batteries can be used. In addition, since the part taken out of the battery exterior material (battery case) does not have a distance from the heat source of the automobile, it does not affect the automobile parts (especially electronic devices) by contacting them and causing a short circuit. It is preferable to coat with a heat-shrinkable heat-shrinkable tube or the like.
[0069]
FIG. 10 is a perspective view showing an appearance when the bipolar battery manufactured in the first embodiment or the second embodiment is configured as a battery 100 by an aluminum laminate pack. In the battery 100, the positive electrode and the negative electrode terminal plates described above are provided on the current collector 1 located at both ends of the bipolar battery, and leads are further attached to form electrodes 101 and 102.
[0070]
Next, an experimental example in which the bipolar battery manufactured according to the first embodiment or the second embodiment is actually evaluated will be described.
[0071]
Experimental example <Evaluation of liquid junction>
A bipolar battery was manufactured according to the manufacturing procedure of the first embodiment or the second embodiment described above, and a liquid junction between the unit cell layers 20 was evaluated.
[0072]
(Sample preparation)
The bipolar battery actually manufactured as an example is as follows.
[0073]
The current collector 1 uses a stainless steel (SUS) foil of 20 μm, and only one of the positive electrode active material layer 2 and the negative electrode active material layer 3 is formed on the current collector 1 located at both ends of the lamination. A positive electrode active material layer 2 and a negative electrode active material layer 3 were formed on the current collector 1 of Example 1.
[0074]
The positive electrode active material layer 2 is obtained by mixing LiMn ₂ O ₄ with acetylene black as a conductive additive, polyvinylidene fluoride (PVDF) as a binder, and N-methyl-2-pyrrolidone (NMP) as a viscosity adjusting solvent to form a positive electrode slurry. The positive electrode active material was prepared and applied as a positive electrode active material to one surface of a stainless steel foil (thickness: 20 μm) as a current collector and dried to form a positive electrode active material layer 2 having a thickness of 40 μm.
[0075]
The negative electrode active material layer 3 was prepared by mixing Li ₄ Ti ₅ O ₁₂ with acetylene black as a conductive additive, PVDF as a binder, and NMP as a viscosity adjusting solvent to prepare a negative electrode slurry. Is applied to the opposite surface of the stainless steel foil coated with and then dried to form a negative electrode active material layer 3 having a thickness of 50 μm.
[0076]
The gel electrolyte layer 4 is composed of a 50 μm thick polypropylene (PP) undifferentiated cloth, a polymer (copolymer of polyethylene oxide and polypropylene oxide) 5 wt%, a mixing ratio of 1: 3 ethylene carbonate (EC) + dimethyl carbonate ( A gel electrolyte comprising 95% by weight of DMC (DMC) and 1.0 mol / l of Li (C ₂ F ₅ SO ₂ ) ₂ N with respect to the EC + DMC electrolyte.
[0077]
A bipolar electrode 10 is formed by the current collector 1, the positive electrode active material layer 2, and the negative electrode active material layer 3, and the positive electrode active material layer 2 and the negative electrode active material layer 3 are laminated with the gel electrolyte layer 4 interposed therebetween. did. After lamination, the mold 40 was fitted around the outer periphery of the battery structure, the molten resin was poured into the mold 40, and after curing, a sealing member made of the resin 60 was formed on the side surface of the electrode laminate 30. The resin 60 as a sealing member was formed on all four side surfaces of the electrode stack 30, and the gel electrolyte layer 4 was sealed in the bipolar battery. The number of stacked unit cells 20 was five.
[0078]
As a comparative example of this evaluation, a bipolar battery having the same structure except that the resin 60 as a sealing member was not provided on the side surface of the electrode laminate 30 was formed.
[0079]
The evaluation of the liquid junction was performed by performing a charge / discharge cycle test of the bipolar batteries of the example and the comparative example. In the charge / discharge cycle, the battery was charged with a current of 0.5 C and discharged with a current of 0.5 C, which was defined as one cycle.
[0080]
(Evaluation results)
In the bipolar battery of the example, a liquid junction (short circuit) between the electrodes did not occur even if the charge and discharge cycle exceeded 50 cycles, and the output voltage was maintained.
[0081]
On the other hand, in the bipolar battery of the comparative example, during the initial charging, the electrolyte oozes out of the unit cell layer and comes into contact with the gel electrolyte of the other unit cells to cause a liquid junction, and the battery voltage is reduced. Markedly reduced.
[0082]
From this evaluation result, it can be seen that by using a bipolar battery in which the resin 60 is formed on the outer periphery of the electrode laminate 30 as the sealing member, liquid junction between the cells can be reliably prevented.
[0083]
In addition, based on the manufacturing method of 2nd Embodiment, the experiment was similarly performed about the bipolar battery which immersed the side surface of the electrode laminated body 30 in the water tank containing resin, and supplied resin to four side surfaces. In this experiment, results similar to the above (evaluation results) were obtained.
[0084]
(Third embodiment)
A third aspect of the present invention is an assembled battery in which a plurality of bipolar batteries manufactured by the method for manufacturing a bipolar battery according to the first or second embodiment are connected in parallel and / or in series.
[0085]
FIG. 11 is a perspective view of the battery pack according to the third embodiment, and FIG. 12 is a view of the internal structure of the battery pack as viewed from above.
[0086]
As shown in FIG. 11 and FIG. 12, the battery pack 70 is formed by connecting a plurality of directly connected batteries 100 (see FIG. 10) in which the bipolar battery according to the first embodiment is packaged by a laminate pack, and further connected in parallel. It was done. In the batteries 100, the electrodes 101 and 102 of each battery are connected by a conductive bar 53. In the battery pack 110, electrode terminals 111 and 112 are provided on one side surface of the battery pack 110 as electrodes of the battery pack 110.
[0087]
In this assembled battery, ultrasonic welding, heat welding, laser welding, rivets, caulking, electron beam, or the like can be used as a connection method when the batteries 100 are directly connected and further connected in parallel. By employing such a connection method, a battery pack having long-term reliability can be manufactured.
[0088]
According to the battery pack according to the third embodiment, a high capacity and high output can be obtained by using the battery manufactured in the above-described first embodiment or the second embodiment to make a battery pack, and Since the reliability of each battery is high, the long-term reliability of the assembled battery can be improved.
[0089]
The connection of the batteries 100 as the assembled battery may be performed by connecting all of the batteries 100 in parallel or by connecting all of the batteries 100 in series.
[0090]
(Fourth embodiment)
A fourth aspect of the present invention is a vehicle equipped with the bipolar battery manufactured by the method for manufacturing a bipolar battery according to the first or second embodiment or the battery pack 110 according to the third embodiment as a driving power supply. is there. A vehicle using the bipolar battery or the battery pack 110 as a power source for a motor is a vehicle whose wheels are driven by a motor, such as an electric vehicle or a hybrid vehicle.
[0091]
For reference, FIG. 13 shows a schematic diagram of an automobile 130 on which the battery pack 110 is mounted. The battery pack 110 mounted on the vehicle has the characteristics described above. For this reason, an automobile equipped with the battery pack 110 has high durability and can provide a sufficient output even after being used for a long period of time.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a manufacturing procedure of the bipolar battery of the present invention.
FIG. 2 is a sectional view showing electrodes of a bipolar battery.
FIG. 3 is a cross-sectional view showing a state in which electrodes are stacked with a gel electrolyte layer interposed therebetween.
FIG. 4 is a perspective view showing a state in which a mold is fitted to the electrode laminate.
FIG. 5 is a cross-sectional view showing a state where a mold is fitted to the electrode laminate.
FIG. 6 is a cross-sectional view showing a state of the electrode laminate after removing the mold.
FIG. 7 is a partial cross-sectional view of a bipolar battery in which an insulating layer is laminated on a current collector 1.
FIG. 8 is a flowchart showing a manufacturing procedure of the bipolar battery of the present invention.
FIG. 9 is a diagram showing a state of a manufacturing process of the bipolar battery.
FIG. 10 is a perspective view showing an appearance when a bipolar battery manufactured by the manufacturing method of the present invention is formed as a battery by an aluminum laminate pack.
FIG. 11 is a perspective view of a battery pack according to a third embodiment.
FIG. 12 is a drawing of the internal configuration of the battery pack viewed from above.
FIG. 13 is a schematic view of an automobile equipped with a battery pack.
[Explanation of symbols]
1 ... current collector,
2 ... Positive electrode active material layer,
3: Negative electrode active material layer,
4 ... Gel electrolyte layer,
5 ... insulating layer,
10 ... Bipolar electrode,
20 ... cell layer,
30 ... electrode laminate,
40 ... type,
53 ... conductive bar,
60 ... resin,
70 ... battery pack,
100 ... battery,
110 ... battery pack,
130 ... Car.

Claims (9)

The gel electrolyte layer is sandwiched between a plurality of sheet-shaped electrodes, and the side faces of the electrode laminate are inserted into a mold having a notch matching the side faces, and the resin melted in the mold. And a resin for curing the resin to prevent leakage of the gel electrolyte to form a sealing member. A gel electrolyte layer is sandwiched between a plurality of sheet-shaped electrodes, and the side surfaces of the laminated electrode laminate are immersed in a water bath filled with a molten resin, taken out, and attached to the electrode laminate. A method for manufacturing a laminated battery, wherein the resin is cured to form a sealing member for preventing leakage of gel electrolyte. The method for producing a laminated battery according to claim 1, wherein when laminating the gel electrolyte layer between a plurality of sheet-like electrodes, an insulating member is provided on a current collector constituting the electrodes. The method according to any one of claims 1 to 3, wherein the sealing member is a resin selected from the group consisting of silicon, epoxy, urethane, polybutadiene, polypropylene, polyethylene, and paraffin wax. The electrode is
A bipolar electrode comprising a current collector, a positive electrode active material layer, and a negative electrode active material layer, wherein a positive electrode active material layer is formed on one surface of the current collector, and a negative electrode active material layer is formed on the other surface. hand,
The method for manufacturing a laminated battery according to any one of claims 1 to 4, wherein the positive electrode active material layer and the negative electrode active material layer are laminated so as to face each other with a gel electrolyte interposed therebetween. The positive electrode active material layer contains a composite oxide of lithium and a transition metal,
The method according to claim 5, wherein the negative electrode active material layer contains a composite oxide of carbon or lithium and a transition metal. A multilayer battery manufactured by the method for manufacturing a multilayer battery according to claim 1. An assembled battery comprising a plurality of the laminated batteries according to claim 7 connected to each other. A vehicle comprising the stacked battery according to claim 7 or the battery pack according to claim 8 mounted as a driving power source.

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