JP2005276486A - Laminated battery, battery pack, and vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bipolar battery in which a tab for extracting electric current to the outside of a battery is not used, and reduction of output caused by passing through the tab is prevented. <P>SOLUTION: The bipolar battery 30 is a laminated type battery in which a laminated body wherein a sheet-shaped electrode 1 is laminated interposing an electrolyte layer is sealed by a sheet-shaped laminate sheet. Since the laminate sheet contacts a current collector of the outermost layer of the laminated body in the sealed interior, a part of conductive layer is exposed outside so as to function as a terminal for extracting the current. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminated battery in which sheet-like electrodes are laminated with an electrolyte layer interposed therebetween, an assembled battery in which a plurality of the laminated batteries are connected, and a vehicle equipped with the laminated battery or the assembled battery.

  In recent years, reduction of carbon dioxide emissions has been strongly desired for environmental protection. In the automobile industry, there are high expectations for reducing carbon dioxide emissions by introducing electric vehicles (EVs) and hybrid electric vehicles (HEVs), and we are eager to develop secondary batteries for motor drives that hold the key to their practical application. Has been done. As a secondary battery, attention is focused on a stacked battery that can achieve a high energy density and a high output density.

  In a stacked battery, sheet-like electrodes are electrically connected in series in a battery package with an electrolyte layer in between, and current flows in the electrode stacking direction, that is, in the thickness direction of the battery. Is wide and high output can be obtained.

  In such a conventional stacked battery, the electrode includes a current collector, a positive electrode active material layer, and a negative electrode active material layer, current collectors are disposed at both ends of the stack, and the current collectors at both ends are electrodes. It is connected to a tab (terminal) and pulled out of the battery package (see, for example, Patent Document 1).

  However, in the bipolar battery as described above, when the current is drawn out of the battery package, the current flows along the length direction of the tab. In addition, although current flows in the stacking direction of the electrodes in the middle of the stack, current flows along the length direction of the current collector in the current collectors at both ends.

In this case, since the current flows through the current collectors at the tabs and both ends of the stack, the output is reduced due to the resistance, which may reduce the efficiency or cause excessive heat generation.
JP 2002-75455 A (FIGS. 1 and 2)

  The present invention has been made in view of the above circumstances, and does not use a tab to draw current to the outside of the battery, but can prevent a decrease in output due to passing through the tab. It aims at providing the assembled battery and the vehicle which mounts a laminated battery or an assembled battery.

  (1) The laminated battery of the present invention is a laminated battery in which a laminate in which sheet-like electrodes are laminated with an electrolyte layer interposed therebetween is sealed with a sheet-like laminate sheet, In the sealed interior, the conductive layer is exposed in part in order to function as a terminal for taking out an electric current because it contacts the current collector of the outermost layer of the laminate.

  (2) The assembled battery of the present invention includes a plurality of the stacked batteries of (1) above and is connected in series so that a terminal functioning as a positive electrode and a terminal functioning as a negative electrode are connected.

  (3) The assembled battery of the present invention includes a plurality of the stacked batteries of the above (1), a terminal that functions as a positive electrode of each stacked battery is connected to one current collector plate, and a terminal that functions as a negative electrode is another It is connected to the current collector plate and connected in parallel.

  (4) The vehicle of the present invention includes the stacked battery of (1) or the assembled battery of (2) or (3) as a driving power source.

  According to the laminated battery of (1) above, since the laminate sheet is in contact with the current collector of the outermost layer of the laminate inside the sealed interior, it functions as a terminal for taking out the current outside. The conductive layer is exposed at the part. Therefore, a configuration for taking out a current such as a tab connected to the current collector and drawn out of the battery is not required. Thereby, the loss at the time of an electric current passing a tab can be prevented. The stacked battery of the present invention having such characteristics is a useful power source in various industries such as a vehicle power source. In addition, since a tab is not required for taking out the current, the degree of freedom in design is high when connecting the stacked batteries in series and / or in parallel.

  According to the assembled battery of the above (2), it is possible to form an assembled battery by connecting a plurality of stacked batteries and connecting them in series without requiring a special member. Since it is easy to connect each stacked battery, even if there is a defective product, it is possible to use the non-defective product as it is by simply replacing the defective product. Since they are connected in series, an assembled battery with a large output can be obtained.

  According to the assembled battery of (3) above, it is possible to form an assembled battery by simply connecting a plurality of stacked batteries and connecting them in parallel without requiring a special member. Since it is easy to connect each stacked battery, even if there is a defective product, it is possible to use the non-defective product as it is by simply replacing the defective product. Since it is connected in parallel, a long-life battery pack can be obtained.

  According to the vehicle of the above (4), it is possible to provide a compact vehicle power source having various characteristics such as the stacked battery of the above (1) or the assembled battery of the above (2) and (3).

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, each component is exaggerated for clarity of explanation.

(First embodiment)
The first of the present invention is a laminated battery in which a laminate in which sheet-like electrodes are laminated with an electrolyte layer interposed therebetween is sealed with a sheet-like laminate sheet, and the laminate sheet is sealed inside, In order to be in contact with the current collector of the outermost layer of the laminate, the conductive layer is partially exposed to function as a terminal for taking out current. In the present embodiment, a case where the stacked battery is a bipolar battery will be described.

  FIG. 1 is a cross-sectional view showing electrodes of a bipolar battery, and FIG. 2 is a cross-sectional view showing how electrodes are stacked with an electrolyte layer interposed therebetween.

  As shown in FIG. 1, a sheet-like bipolar electrode 10 constituting a bipolar battery has a positive electrode active material layer 2 disposed on one surface of an integrated current collector 1 and a negative electrode active material on the other surface. It has a structure in which the layer 3 is arranged. In other words, the positive electrode active material layer 2, the current collector 1 and the negative electrode active material layer 3 have a structure in which they are stacked in this order.

  As shown in FIG. 2, the electrodes 10 having the above structure are all arranged so that the stacking order is the same, and are stacked with the electrolyte layer 4 interposed therebetween. By filling the electrolyte layer 4 between the positive electrode active material layer 2 and the negative electrode active material layer 3, the ion conduction becomes smooth, and the output of the entire bipolar battery can be improved.

  By using a solid electrolyte for the electrolyte layer 4, there is no leakage of electrolyte, and no configuration for preventing the dissolution is required, so that the configuration of the bipolar battery can be simplified. When a liquid or semi-solid gel substance is used for the electrolyte layer 4, it is necessary to seal between the current collectors 1 so that the electrolyte does not leak.

  Note that a layer including the negative electrode active material layer 3, the 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.

  Next, the overall configuration of the bipolar battery of the present invention will be described.

  FIG. 3 is a sectional view showing the structure of the bipolar battery, and FIG. 4 is a plan view of the bipolar battery of the present invention.

  When the bipolar electrode 10 and the electrolyte layer 4 are alternately laminated and applied to the bipolar battery 30, as shown in FIG. 3, the bipolar electrode 10 is always arranged in the outermost layer of the lamination. Among the outermost bipolar electrodes 10, a current collector 1 a that functions as a positive electrode and a current collector 1 b that functions as a negative electrode are disposed in the outermost layer. Therefore, the current collector 1a functioning as the positive electrode does not have the negative electrode active material layer 3 formed outside the current collector 1a, and the current collector 1b functioning as the negative electrode is active outside the current collector 1b. The material layers 2 are stacked without being formed.

  The laminate 6 laminated from the current collector 1a to the current collector 1b is covered with two laminate sheets 5 from above and below. The laminate sheet 5 is a polymer metal composite film in which a heat-fusible resin film (insulating layer) 5a, a metal foil (conductive layer) 5b, and a rigid resin film (insulating layer) 5c are laminated in this order. The heat-fusible resin film 5a is formed from polyolefin, such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene, for example. The metal foil 5b is made of, for example, aluminum or nickel. The resin film 5c is formed from polyester (PET or the like), polyamide (nylon ((registered trademark)), or the like.

  As shown in FIGS. 3 and 4, the laminate sheet 5 has the metal foil 5 b exposed at the center. In order to expose only the center, it is conceivable to perform solvent treatment, heat treatment, flame treatment or the like on the laminate sheet 5 in the state where the metal foil 5b is not exposed at the center. For example, the metal foil 5b is exposed to the heat-fusible resin film 5a by subjecting the center to a high temperature using an organic solvent such as toluene, perchlorethylene, trichloroethylene, or carbon tetrachloride. Moreover, with respect to the resin film 5c, the metal foil 5b is exposed by processing the center using organic solvents, such as cresol. Further, as another method for producing the laminate sheet 5 from which the metal foil 5b is exposed, a film obtained by heat-sealing the heat-fusible resin film 5a with the central portion cut out to the metal foil 5b may be simply used.

  Thus, the laminate sheet 5 from which the metal foil 5b is exposed is superposed so that the heat-fusible resin film 5a faces each other, and heat is applied to the four sides while being decompressed. Thereby, the heat-fusible resin film 5a is melted, and the laminate 6 is sealed under reduced pressure. Further, the end portion of the laminate sheet 5 is covered and held by a sealing resin 50 such as an epoxy resin.

  In the bipolar battery 30 configured as described above, the metal foil 5b exposed at the center of the laminate sheet 5 is in contact with the current collector 1a and the current collector 1b of the laminate 6. Therefore, the current can be taken directly from the exposed metal foil 5b of the laminate sheet 5. That is, the exposed surface of the metal foil 5b of the laminate sheet 5 serves as a positive electrode terminal and a negative electrode terminal.

  FIG. 5 is a sectional view showing the direction of current flowing in the bipolar battery 30 of the present invention.

  In the bipolar battery 30, as indicated by arrows in FIG. 5, the current flows in the lamination direction of the bipolar electrode 10 from the upper laminate sheet 5 to the lower laminate sheet in the figure. Therefore, the current flowing in the stacking direction of the stacked body 6 can be taken out of the battery without changing the direction.

  As described above, in the bipolar battery 30 of the present invention, the metal foil 5b is exposed at the center of the laminate sheet 5, and the metal foil 5b functions as a positive electrode terminal and a negative electrode terminal. Therefore, it is not necessary to attach a structure for taking out a current such as a tab to the current collector 1 in order to take out current outside the battery, and loss due to resistance of the tab when the current passes through the tab can be prevented. Further, the laminate sheet 5 itself becomes a terminal, and a separate tab is not required. Therefore, current does not flow along the current collector toward the tab, the current passing distance is shortened, and current loss can be reduced. Since a tab is not required, when a plurality of stacked batteries are connected in series and / or in parallel, the degree of freedom in design is high.

  Further, in the bipolar battery 30, the end portion of the laminate sheet 5 is covered and held by a sealing resin 50 such as an epoxy resin. Therefore, the metal foil 5b of the laminated laminate sheet 5 does not contact at the end portion, and a short circuit due to this can be prevented.

  In addition, if the electrolyte layer is made of a solid polymer, there is no leakage of the electrolyte, and it is not necessary to seal the electrolyte with a resin or the like in order to prevent the leakage, and the configuration of the bipolar battery 30 can be simplified.

  3 and 5, each layer of the laminate 6 and the thickness of the laminate sheet 5 are exaggerated. For this reason, the current collectors 1a, 1b and the metal foil 5b do not appear to be in contact with each other, but needless to say, they are actually in contact.

  The configuration of the bipolar battery 30 of the present invention has been described above. Subsequently, the materials of the current collector 1, the positive electrode active material layer 2, the negative electrode active material layer 3, the electrolyte layer 4, and the laminate sheet 5 in the bipolar battery 30 of the present invention will be described for reference. There is no particular limitation as long as a known material is used.

[Current collector]
The current collector has a surface material of aluminum. When the surface material is aluminum, an active material layer having high mechanical strength is obtained even when the formed active material layer contains a solid polymer electrolyte. If the surface material of the current collector is aluminum, the structure thereof is not particularly limited. The current collector may be aluminum itself. In addition, the surface of the current collector may be covered with aluminum. That is, a current collector in which aluminum is coated on the surface of a substance other than aluminum (such as copper, titanium, nickel, SUS, or an alloy thereof) may be used. In some cases, a current collector in which two or more plates are bonded together may be used. From the viewpoint of corrosion resistance, ease of production, economy, and the like, it is preferable to use an aluminum foil alone as a current collector. Although the thickness of a collector is not specifically limited, Usually, it is about 10-100 micrometers.

[Positive electrode active material layer]
The positive electrode active material layer includes a positive electrode active material and a solid polymer electrolyte. In addition to this, a supporting salt (lithium salt) for increasing ionic conductivity, a conductive auxiliary agent for increasing electronic conductivity, NMP (N-methyl-2-pyrrolidone) as a solvent for adjusting slurry viscosity, a polymerization initiator AIBN (azobisisobutyronitrile) and the like may be included.

As the positive electrode active material, a composite oxide of lithium and a transition metal, which is also used in a solution-type 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 Examples thereof include Fe-based composite oxides. 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 etc. are mentioned. By using a lithium-transition metal composite oxide as the positive electrode active material layer active material, the reactivity and cycle durability of the stacked battery can be improved and the cost can be reduced.

  In order to reduce the electrode resistance of the bipolar battery, the positive electrode active material may have a particle size smaller than that generally used in a solution type lithium ion battery in which the electrolyte is not solid. Specifically, the average particle diameter of the positive electrode active material is preferably 0.1 to 5 μm.

The solid polymer electrolyte is not particularly limited as long as it is a polymer having ion conductivity. Examples of the polymer having ion conductivity include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. Such polyalkylene oxide polymers can well dissolve lithium salts such as LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) ₂ . Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure. In the present invention, the solid polymer electrolyte is contained in at least one of the positive electrode active material layer and the negative electrode active material layer. However, in order to further improve the battery characteristics of the bipolar battery, it is preferable to be included in both.

As the supporting salt, Li (C ₂ F ₅ SO ₂ ) ₂ N, LiBF ₄ , LiPF ₆ , LiN (SO ₂ C ₂ F ₅ ) ₂ , or a mixture thereof can be used. However, it is not necessarily limited to these.

  Examples of the conductive assistant include acetylene black, carbon black, and graphite. However, it is not necessarily limited to these.

  The amount of the positive electrode active material, solid polymer electrolyte, lithium salt, and conductive additive in the positive electrode active material layer should be determined in consideration of the intended use of the battery (output priority, energy priority, etc.) and ion conductivity. is there. For example, if the amount of the solid polymer electrolyte in the active material layer is too small, the ionic conduction resistance and the ionic diffusion resistance in the active material layer will increase, and the battery performance will deteriorate. On the other hand, if the amount of the solid polymer electrolyte in the active material layer is too large, the energy density of the battery is lowered. Therefore, in consideration of these factors, the solid polymer electrolytic mass meeting the purpose is determined.

Here, the case where a bipolar battery giving priority to battery reactivity is manufactured using a solid polymer electrolyte (ionic conductivity: 10 ⁻⁵ to 10 ⁻⁴ S / cm) at the current level will be specifically considered. In order to obtain a bipolar battery having such characteristics, the electron conduction resistance between the active material particles is kept low by increasing the conductive auxiliary agent or reducing the bulk density of the active material. At the same time, the gap is increased, and the gap is filled with a solid polymer electrolyte. The ratio of the solid polymer electrolyte may be increased by such treatment.

  The thickness of the positive electrode active material layer is not particularly limited, and should be determined in consideration of the intended use of the battery (such as emphasis on output and energy) and ion conductivity, as described for the blending amount. The thickness of a general positive electrode active material layer is about 5 to 500 μm.

[Negative electrode active material layer]
The negative electrode active material layer includes a negative electrode active material and a solid polymer electrolyte. In addition to this, a supporting salt (lithium salt) for increasing ionic conductivity, a conductive auxiliary agent for increasing electronic conductivity, NMP (N-methyl-2-pyrrolidone) as a solvent for adjusting slurry viscosity, a polymerization initiator AIBN (azobisisobutyronitrile) and the like may be included. Except for the type of the negative electrode active material, the contents are basically the same as those described in the section “Positive electrode active material”, and thus the description thereof is omitted here.

  As the negative electrode active material, a negative electrode active material that is also used in a solution-type lithium ion battery can be used. However, since the solid polymer electrolyte is used in the bipolar battery of the present invention, a composite oxide of carbon or lithium and a metal oxide or metal is preferable in consideration of the reactivity with the solid polymer electrolyte. More preferably, the negative electrode active material is a composite oxide of carbon or lithium and a transition metal. More preferably, the transition metal is titanium. That is, the negative electrode active material is more preferably titanium oxide or a composite oxide of titanium and lithium.

  By using a composite oxide of carbon or lithium and a transition metal as the negative electrode active material layer active material, the reactivity and cycle durability of the stacked battery can be improved and the cost can be reduced.

[Electrolyte layer]
The material is not limited as long as it is a layer composed of a polymer having ion conductivity and exhibits ion conductivity. It is preferable to use a solid electrolyte for preventing liquid leakage. Examples of the solid electrolyte include known solid polymer electrolytes such as polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. The solid polymer electrolyte layer contains a supporting salt (lithium salt) in order to ensure ionic conductivity. As the supporting salt, LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , or a mixture thereof can be used. However, it is not necessarily limited to these. A polyalkylene oxide polymer such as PEO and PPO can dissolve lithium salts such as LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) ₂ well. Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure.

  The solid polymer electrolyte may be included in the solid polymer electrolyte layer, the positive electrode active material layer, and the negative electrode active material layer, but the same solid polymer electrolyte may be used, and a different solid polymer electrolyte is used depending on the layer. Also good.

[Laminate sheet]
The laminate sheet is used as a battery exterior material. In general, a polymer metal composite film in which a heat-fusible resin film, a metal foil, and a resin film having rigidity are laminated in this order is used.

  As the heat-fusible resin, for example, polyethylene (PE), polypropylene (PP), modified polyethylene, modified polypropylene, ionomer, ethylene vinyl acetate (EVA) and the like can be used. As the metal foil, for example, Al foil or Ni foil can be used. As the resin having rigidity, polyamide synthetic fibers such as polyester such as polyethylene terephthalate (PET) and polyamide (nylon (registered trademark)) can be used. Specifically, a PE / Al foil / PET laminated film laminated from the sealing surface side to the outer surface; a PE / Al foil / nylon (registered trademark) laminated film; an ionomer / Ni foil / PET laminated film; EVA / Al foil / PET laminated film; ionomer / Al foil / PET laminated film and the like can be used. The heat-fusible resin film acts as a seal layer when the battery element is housed inside. A metal foil or a rigid resin film imparts moisture, breathability, and chemical resistance to the exterior material. The laminate sheet can be easily and reliably bonded using heat sealing such as heat sealing, impulse sealing, ultrasonic welding, and high-frequency welding.

(Example)
Next, an embodiment in which the bipolar battery 30 is actually manufactured and evaluated will be described.

<Sample preparation>
The bipolar battery 30 actually manufactured as an example is as follows.

  The current collectors 1, 1 a, 1 b are made of stainless steel (SUS) foil having a thickness of 20 μm, and the positive electrode active material layer 2 or the negative electrode active material layer 3 is formed on the end current collectors 1 a, 1 b. A positive electrode active material layer 2 and a negative electrode active material layer 3 were formed on the current collector 1.

The positive electrode active material layer 2 is composed of LiMn ₂ O ₄ (85% by weight), acetylene black (5% by weight) as a conductive additive, polyvinylidene fluoride (PVDF) (10% by weight) as a binder, and N— as a viscosity adjusting solvent. An appropriate amount of methyl-2-pyrrolidone (NMP) is mixed to prepare a positive electrode slurry, which is 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 a film thickness of 40 μm. Positive electrode active material layer 2.

The negative electrode active material layer 3 comprises Li ₄ Ti ₅ O ₁₂ (85 wt%), acetylene black (5 wt%) as a conductive auxiliary agent, PVDF (10 wt%) as a binder, and NMP (appropriate amount) as a viscosity adjusting solvent. The negative electrode slurry is applied to the opposite surface of the stainless steel foil coated with the positive electrode active material layer 2 and dried to form a negative electrode active material layer 3 having a thickness of 40 μm.

  The electrolyte layer 4 is a polypropylene (PP) mysterious fabric having a thickness of 50 μm, a monomer solution (copolymer of polyethylene oxide and polypropylene oxide) having an average molecular weight of 7500 to 9000 that is a precursor of an ion conductive polymer matrix, 5 weight. %, 95% by weight of 1.0 mol / l LiBETI dissolved in ethylene carbonate (EC) + dimethyl carbonate (DMC) in a mixing ratio of 1: 3, and a pregel solution composed of a polymerization initiator was permeated. Then, it was sandwiched between quartz glass substrates and irradiated with ultraviolet rays for 15 minutes to crosslink the precursor to obtain a gel polymer electrolyte layer.

  The positive electrode active material layer 2 and the electrolyte layer 4 were laminated on the end current collectors 1a and 1b. Thereafter, the negative electrode active material layer 3 and the current collector 1 were laminated on the electrolyte layer 4. The same process was repeated until five single cell layers 20 were formed, and the laminate 6 was formed.

  Next, among the layers of the laminate sheet 5 having the three-layer structure, the center of the heat-fusible resin film 5a disposed inside when the bipolar battery 30 is assembled was heat-treated at a high temperature. Subsequently, the center of the resin film 5c disposed outside when the bipolar battery 30 was assembled was solvent-treated with cresol. Thereby, the aluminum foil layer (metal layer) 5b was exposed in the center of both surfaces of the laminate sheet 5.

  And the lamination sheet 5 was piled up from the upper and lower sides of the laminated body 6, and the edge part was sealed by thermal fusion | bonding, decompressing the inside. The end portion of the sealed laminate sheet 5 was covered with the epoxy resin 50 to ensure the insulation of the end portion.

  Thus, the bipolar battery 30 was completed.

<Comparative example>
Further, as a comparative example for this evaluation, a structure having substantially the same configuration as that of the above example and having the metal layer 5b not exposed at the center of the laminate sheet 5 was prepared. If the metal layer 5b is not exposed, it does not function as an electrode terminal. Instead, the end current collectors 1a and 1b are extended and pulled out from the package of the laminate sheet 5 to the outside. That is, the end current collectors 1a and 1b are electrode tabs.

<Comparison>
And the alternating voltage amplitude of frequency 1kHz was applied between the positive electrode terminal of the bipolar battery 30 of the said Example, and the bipolar battery of a comparative example, and the negative electrode terminal, and the resistance of the terminal at that time was measured.

  The resistance was 3.5 mΩ for the bipolar battery 30 of the present invention, and 14.3 mΩ for the bipolar battery of the comparative example. This result also shows that the resistance at the terminal is reduced by the present invention.

(Second Embodiment)
The second of the present invention is an assembled battery including a plurality of bipolar batteries 30 described in the first embodiment and connected in series so that a terminal functioning as a positive electrode and a terminal functioning as a negative electrode are connected.

  FIG. 6 is a cross-sectional view showing an assembled battery in which bipolar batteries of the present invention are connected in series.

  As shown in FIG. 6, a high output assembled battery can be obtained by preparing a plurality of bipolar batteries 30 shown in the first embodiment and stacking them to form an assembled battery 60. Here, the order of the cell layers 20 (see FIG. 2) in each bipolar battery 30 is set so that the positive terminal of one adjacent bipolar battery 30 and the negative terminal of another bipolar battery 30 are in contact with each other. Laminate so that they match.

  Thus, in the assembled battery 60 of the present invention, the bipolar batteries 30 can be easily connected in series and formed into an assembled battery by simply stacking a plurality of the bipolar batteries 30 without requiring any special member.

  In addition, since the assembled battery 60 is formed by a plurality of bipolar batteries 30, even if one of the bipolar batteries 30 has a defective product, the subsequent good product can be used as it is simply by replacing the defective product. Are better.

  In the drawing, the gap between the terminals of the bipolar battery 30 is shown, but the actual laminate sheet is very thin and the opening where the terminal surface is exposed is very large. ing.

(Third embodiment)
The third of the present invention includes a plurality of the bipolar batteries 30 of the first embodiment between two current collector plates, the positive terminal of each bipolar battery 30 is connected to one current collector plate, and the negative electrode terminal is the other current collector plate. It is an assembled battery connected to the current collector plate and connected in parallel.

  FIG. 7 is a cross-sectional view showing an assembled battery in which the bipolar batteries of the present invention are connected in parallel.

  As shown in FIG. 7, a plurality of bipolar batteries 30 shown in the first embodiment are prepared, and these are connected in parallel by two current collecting plates 71 and 72 to form a battery pack 70, thereby providing a long life. The assembled battery can be obtained. Here, a plurality of bipolar batteries 30 are disposed between the current collecting plates 71 and 72 such that the positive electrode terminal of each bipolar battery 30 contacts the current collecting plate 71 and the negative electrode terminal of each bipolar battery 30 contacts the current collecting plate 72. Arranged between.

  Thus, in the assembled battery 70 of the present invention, by using the two current collector plates 71 and 72, the bipolar batteries 30 can be connected in parallel with each other with a simple configuration to form an assembled battery.

  In addition, since the assembled battery 70 is formed by a plurality of bipolar batteries 30, even if one of the bipolar batteries 30 has a defective product, the subsequent good product can be used as it is simply by replacing the defective product. Are better.

  In the drawing, the gap between the terminal of the bipolar battery 30 and the current collector plates 71 and 72 is shown. However, the actual laminate sheet is very thin and the opening through which the terminal surface is exposed is very large. Since it is large, the terminal and the current collector plate are in contact with each other.

(Fourth embodiment)
A fourth aspect of the present invention is a vehicle in which the bipolar battery 30 of the first embodiment or the assembled batteries 60 and 70 of the second and third embodiments are mounted as a driving power source.

  FIG. 8 is a diagram showing a vehicle equipped with an assembled battery to which the bipolar battery 30 of the present invention is applied.

  The bipolar battery 30 has various characteristics as described above, and is a particularly compact battery. For this reason, it is suitable as a power source for vehicles in which particularly severe demands are made regarding energy density and power density. In addition, when a polymer solid electrolyte is used for the electrolyte layer, there is a disadvantage that the ionic conductivity is lower than that of the gel electrolyte, but when used in a vehicle, the ambient environment of the bipolar battery must be maintained at a certain high temperature. Can do. Also from this viewpoint, it can be said that the bipolar battery of the present invention is suitable for use in a vehicle.

It is sectional drawing which shows the electrode of a bipolar battery. It is sectional drawing which shows a mode that an electrode is laminated | stacked on both sides of an electrolyte layer. It is sectional drawing which shows the structure of a bipolar battery. It is a top view of the bipolar battery of this invention. It is sectional drawing which shows the direction of the electric current which flows in the bipolar battery of this invention. It is sectional drawing which shows the assembled battery which connected the bipolar battery of this invention in series. It is sectional drawing which shows the assembled battery which connected the bipolar battery of this invention in parallel. It is a figure which shows the vehicle carrying the assembled battery to which the said bipolar battery 30 of this invention is applied.

Explanation of symbols

1, 1a, 1b ... current collector,
2 ... positive electrode active material layer,
3 ... negative electrode active material layer,
4 ... electrolyte layer,
5 ... Laminate sheet,
5a ... heat-fusible resin film,
5b ... metal foil,
5c ... resin film,
6 ... Laminated body,
10: Bipolar electrode,
20: single cell layer,
30 ... Bipolar battery,
50. Seal resin,
60, 70 ... assembled battery,
71, 72 ... current collector plates.

Claims (9)

A laminated battery in which a laminate in which a sheet-like electrode is laminated with an electrolyte layer interposed therebetween is sealed with a sheet-like laminate sheet,
Since the laminate sheet is in contact with the current collector of the outermost layer of the laminate inside the hermetically sealed interior, a laminate type in which the conductive layer is partially exposed to function as a terminal for taking out the current outside. battery.   The laminated battery according to claim 1, wherein the laminate sheet is formed by sandwiching a conductive layer between two insulating layers, and the insulating layer is removed at a portion where the conductive layer is exposed. The electrode is a bipolar electrode in which 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,
3. The stacked battery according to claim 1, wherein the bipolar electrode is a bipolar lithium ion secondary battery in which a plurality of bipolar electrodes are stacked in series with the electrolyte layer interposed therebetween. The positive electrode active material layer includes a composite oxide of lithium and a transition metal,
The stacked battery according to claim 3, wherein the negative electrode active material layer includes a composite oxide of carbon or lithium and a transition metal.   The stacked battery according to claim 1, wherein the electrolyte layer is made of a solid polymer. The laminate is sandwiched and sealed between two laminate sheets,
The laminated battery according to any one of claims 1 to 5, wherein outer edges of the two laminate sheets are fused and further sealed with an insulator.   An assembled battery comprising a plurality of the stacked batteries according to claim 1 and connected in series so that a terminal functioning as a positive electrode and a terminal functioning as a negative electrode are connected.   A plurality of the stacked batteries according to claim 1 are included between two current collector plates, a terminal functioning as a positive electrode of each stacked battery is connected to one current collector plate, and a terminal functioning as a negative electrode is provided. A battery pack connected to another current collector plate and connected in parallel.   A vehicle comprising the stacked battery according to claim 1 or the assembled battery according to claim 7 or 8 as a driving power source.

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