JP4595302B2 - Bipolar battery - Google Patents

Description

  The present invention relates to a battery having a bipolar structure in which at least one series configuration of a combination of a positive electrode and a negative electrode exists, an assembled battery using the battery, and a vehicle equipped with the battery.

  In recent years, in order to promote the introduction of electric vehicles (EV), hybrid vehicles (HEV), and fuel cell vehicles (FCV) against the backdrop of an increase in environmental protection movement, these motor drive batteries have been developed. For this purpose, a rechargeable secondary battery is used. In applications that require high output and high energy density, such as EV, HEV, and FCV motor drive power supplies, it is virtually impossible to make a single large battery. Use an assembled battery that consists of multiple batteries connected. It was common to do. Moreover, a lithium ion secondary battery has been proposed as one battery constituting such an assembled battery.

  On the other hand, lithium-ion secondary batteries with large discharge capacity are also used for batteries for electronic devices such as portable phones and personal computers (consumer use). However, in terms of space factor and light weight, the sheet type is used. In order to increase the voltage and capacity of a sheet-type battery, a sheet-type bipolar battery employing a bipolar electrode unit has been proposed (see, for example, Patent Documents 1 and 2).

  As such a bipolar battery structure, for example, a positive electrode active material is formed on a positive electrode current collector layer of a composite current collector in which one surface is a positive electrode current collector layer and the other surface is a negative electrode current collector layer. Sheet-type bipolar battery and bipolar electrode unit comprising a bipolar electrode unit having a negative electrode active material layer on a negative electrode current collector layer, and using a solid electrolyte as an electrolyte The first set having one or two or more connected in series and the second set having the same number of bipolar electrode units as the first set are arranged in parallel so that they are mirror images of each other with the electrode plate connected to the terminal electrode as the center. The composite current collectors of the at least one bipolar electrode unit that is connected and included in the first set and the bipolar electrode unit in the second set that is in a mirror image relationship with each other are directly and electrically connected by lead wires. There are bipolar battery of the sheet form characterized by comprising a connection (e.g., see Patent Documents 1 and 2.).

  In such a sheet-type bipolar battery, a bag body made of a waterproof sheet is used instead of a conventional metal outer container as an outer container for storing a sheet-like power generation element. Such a waterproof sheet comprises a polyethylene terephthalate layer, an aluminum foil, and an ethylene-acrylic acid copolymer (amount of acrylic acid monomer component per mole of ethylene monomer component: 0.08 mol, MI: 5). A three-layer waterproof sheet is used.

Such a sheet-type bipolar battery does not have an individual metal outer container, so it is thin, lightweight, and has good heat dissipation.Even if the pressure inside the container becomes high due to overcharge, etc. Because of its low impact and superior safety compared to metal containers, it can be widely used in general consumer applications.
JP 2000-1000047 (page 4, left column 25-28, page 6, left column 2-8) JP 2000-195495 (page 4, right column, lines 20 to 24)

However, in the sheet-type bipolar battery described in Patent Documents 1 and 2, sufficient sealing performance and waterproofness can be ensured by using a bag made of a waterproof sheet. Although it can be used in applications, when installing it as an EV, HEV or FCV motor drive power supply or auxiliary power supply, ensure high insulation to add a high voltage unique to the vehicle. Was not made. That is, in a bipolar battery for a vehicle, a high voltage is strongly demanded, and in response to such a request, a single cell constituting a power generation element housed in the battery is laminated to about several tens to several hundreds of cells. The use of a voltage exceeding 400 V has been studied. However, a sheet-type bipolar battery has a configuration in which the power generating element is housed and sealed by bonding a part or all of the periphery thereof by heat fusion using a bag made of a waterproof sheet. In addition, a metal tab (electrode terminal lead) that is electrically connected to both end electrodes of the power generating element is sandwiched between the heat-sealed portions (seal portions) and exposed to the outside of the bag body. Therefore, in the portion of the tab that is sandwiched between the bag heat-sealing portions (sealing portions), the inner layer of the waterproof film is slightly between the tab and the metal layer (aluminum foil) in the waterproof film. Therefore, it is extremely difficult to guarantee insulation that can withstand a voltage exceeding 400 V for vehicles.

  Accordingly, an object of the present invention is to provide a bipolar battery capable of ensuring insulation even when a high voltage is applied, an assembled battery using the battery, and a vehicle equipped with the battery. More specifically, the present invention provides a bipolar battery capable of ensuring insulation between the electrode tab and the metal layer in the exterior film even when a high voltage is applied, an assembled battery using the battery, and a vehicle equipped with these batteries.

The present invention provides a bipolar structure having a combination of a positive electrode and a negative electrode, a polymer metal composite film as an exterior material, and capable of outputting a voltage of 400 V or more. This can be achieved by a bipolar battery having a high resistance layer higher than the metal resistance of the tab metal, wherein the high resistance layer is a metal oxide film having a thickness of 0.5 μm to 5 μm.

According to the present invention, in a high voltage battery having a bipolar structure and capable of outputting a voltage of 400 V or more, a high resistance layer higher than at least the metal resistance of the tab metal is provided on the tab metal surface, and the high resistance layer is provided. By using a metal oxide film with a film thickness of 0.5 μm to 5 μm, insulation between the bipolar terminals can be ensured even when a high voltage is applied to the tab portion of the bipolar battery. Therefore, the electromotive force of the battery is high, and the battery can be suitably used for a motor drive power source for vehicles that require high insulation. In the case of a battery used for general consumer use (for example, a battery for a mobile phone or a portable personal computer has a voltage of about several volts to 20 volts so as not to cause a problem even if an electric shock is caused by electric leakage during carrying) Over spec. Furthermore, when using a high-resistance film for the high-resistance layer, high adhesion strength can be expressed by the anchor effect in the tab portion where the sealing performance of the battery is most required due to the minute uneven shape of the film, Battery seal reliability is greatly improved.

  The bipolar battery according to the present invention includes a plurality of combinations of positive and negative electrodes, and a bipolar battery having a polymer metal composite film as an exterior material. The resistance is higher than at least the metal resistance of the tab metal on the tab metal surface. It is characterized by having a layer. Hereinafter, embodiments of the present invention will be described.

The bipolar battery that is the subject of the present invention is not particularly limited. For example, when the bipolar battery is distinguished by the structure and form of the bipolar battery, it is a stacked type (flat type) battery or a wound type (cylindrical type). The battery is not particularly limited, and can be applied to any conventionally known structure. Similarly, when distinguished by the type of electrolyte of the bipolar battery, there is no particular limitation, and a high level of liquid electrolyte type battery or polymer battery in which an electrolytic solution is impregnated in a separator (including a nonwoven fabric separator) is also used. The present invention can be applied to both a molecular gel electrolyte type battery and a solid polymer electrolyte (all solid electrolyte) type battery. Among these electrolytes, polymer gel electrolytes and solid polymer electrolytes (all solid electrolytes) can be used alone, or these polymer gel electrolytes and solid polymer electrolytes (all solid electrolytes) can be used as separators. It is not particularly limited, for example, it can be used by impregnating (including a nonwoven fabric separator). Further, although it can be applied to both primary batteries and secondary batteries, the purpose of the present invention is to ensure high insulation for applying a high voltage peculiar to vehicles. It is desirable to apply to batteries. Furthermore, when viewed from the electrode material of the bipolar battery or metal ions moving between the electrodes, the bipolar lithium ion secondary battery, bipolar sodium ion secondary battery, bipolar potassium ion secondary battery, bipolar nickel metal hydride secondary battery, A bipolar nickel cadmium secondary battery, a nickel metal hydride battery and the like are not particularly limited, and can be applied to any conventionally known electrode material. A bipolar lithium ion secondary battery is preferable. This is because a bipolar lithium ion secondary battery has a large cell (single cell layer) voltage, can achieve high energy density and high output density, and is excellent as a vehicle driving power source or an auxiliary power source. Therefore, in the following description, a bipolar lithium ion secondary battery will be described as an example, but the present invention should not be limited to these.

  Hereinafter, specific embodiments of the bipolar battery of the present invention will be described with reference to the drawings.

  FIG. 1A is a plan view schematically showing one embodiment of a bipolar battery according to the present invention. FIG.1 (b) is the sectional view on the AA line of Fig.1 (a), and is the cross-sectional schematic diagram typically showing one Embodiment of the laminated structure of a bipolar battery. FIG. 1C is a cross-sectional view taken along line BB of FIG. 1A, in which a metal tab of a bipolar battery is sandwiched between heat-sealed portions (seal portions) of a polymer metal composite film of an exterior material. 1 is a schematic cross-sectional view schematically showing an embodiment of a laminated structure of a portion.

  As shown in FIG. 1B, the bipolar battery 1 of the present invention has a so-called bipolar structure in which a plurality of series configurations of combinations of a positive electrode and a negative electrode exist. The bipolar structure here means that a positive electrode layer (also referred to as a positive electrode active material layer) is provided on one side of a current collector composed of one or more sheets, and a negative electrode layer (also referred to as a negative electrode active material layer) on the other side. And the positive electrode and the negative electrode of the adjacent bipolar electrode 3 with the electrolyte layer 5 sandwiched therebetween. That is, in the bipolar battery 1, an electrode stack having a structure in which a plurality of bipolar electrodes 3 having a positive electrode layer on one surface of the current collector and a negative electrode layer on the other surface are stacked via the electrolyte layer 5. A body (also referred to as a power generation element, a battery element or a bipolar battery body) 9.

  In the present invention, the uppermost layer electrode 3a and the lowermost layer electrode 3b, which are the outermost parts of the electrode laminate 9 in which a plurality of the bipolar electrodes 3 are laminated, may not be bipolar electrodes. A structure (non-bipolar electrode structure) in which a positive electrode layer or a negative electrode layer is provided on only one side of the current collector / positive electrode plate and the lowermost current collector / negative electrode plate. In addition, an insulating layer 7 is formed around each electrode in order to prevent current collectors from coming into contact with each other, electrolyte leaking out, and short-circuiting due to slight unevenness at the end of the laminated electrode. Has been.

In the bipolar battery of the present invention, a positive terminal plate and a negative terminal plate (not shown) may be joined separately from the outermost current collector. Further, as shown in FIG. 1B, the positive and negative electrode tabs 11 and 13 taken out of the battery are electrically connected to the current collectors (or electrode terminal plates) of the outermost electrodes 3a and 3b. For this purpose, the positive and negative electrode leads 15 and 17 may be electrically connected, but the positive electrode and negative electrode tabs taken out of the battery may be directly connected to the current collector (or electrode terminal plate) of the outermost electrode. It is not particularly limited, for example, a part of the current collector (or electrode terminal plate) of the outermost electrode may be extended to form a positive electrode and a negative electrode lead. The positive and negative electrode tabs 11 and 13 are connected to a vehicle load (motor, electrical component, etc.) not shown, and a very large charge / discharge current flows through these electrode tabs 11 and 13. Therefore, the width and thickness (in other words, the cross-sectional area) of the positive electrode tab and the negative electrode tabs 11 and 13 are determined mainly by the current value at the time of charging / discharging that will flow therethrough. Further, in order to prevent external impact and environmental degradation during use, the electrode laminate 9 was sealed under reduced pressure in the battery outer packaging 19 and the positive and negative electrode tabs 11 and 13 were taken out of the battery outer packaging 19. It is a structure. From the viewpoint of weight reduction, the battery casing material 19 is made of a thin film or foil (metal layer 19b) of a metal (including an alloy) such as aluminum, stainless steel, nickel, or copper, and an insulating resin film (skin resin) such as a polypropylene film. A polymer metal composite laminate film covered with a layer 19a and a metal layer-tab resin layer 19c) is used. Then, a part or all of the peripheral part of the battery outer packaging material 19 is joined by heat fusion or the like, so that the electrode laminate 9 is accommodated and sealed (sealed) under reduced pressure. The structure is taken out of the material 19.

  The number of laminations of the bipolar electrode (including the outermost non-bipolar electrode) is adjusted according to the desired voltage. For example, in the case of a vehicle, since the voltage between the terminals of the single battery is 4.2 V, the voltage between the terminals of the battery element 9 (battery of the battery element 9 having a structure in which single battery layers for several tens to hundreds of tens of cells are connected in series. Voltage) is a high voltage exceeding 400V. As described above, in the bipolar battery, the voltage between terminals of one single battery layer does not use a bipolar electrode, and is higher than the voltage between terminals of a general secondary battery such as a lithium ion secondary battery. A high voltage battery can be easily constructed. Therefore, it is indispensable to have the following configuration requirements that can ensure high insulation for applying a high voltage peculiar to the vehicle.

  That is, in the bipolar battery 1 of the present invention, it is necessary to have a resistance layer 21 higher than the metal resistance of at least the tab metal on the metal surfaces of the positive electrode tab and the negative electrode tabs 11 and 13. This is likely to cause dielectric breakdown between the metal layer and the tab of the polymer metal composite film as the exterior material. Therefore, the insulation as a whole can be ensured by having the high resistance layer such as a high resistance film on the tab surface. Furthermore, the high resistance layer (film) on the metal surface of the tab has a fine uneven shape, and can provide an anchor effect in bonding the seal portion of the tab, greatly improving the sealing strength of the battery. Can do.

  The high resistance layer (high resistance film) may be on the metal surface of the tab (see FIG. 1C), that is, the high resistance film does not necessarily have to be provided on the entire length of the tab. It may be provided only on a part of the tab. When the tab is connected to the outside of the battery, if a high resistance layer is present on the surface, the contact resistance increases, which is not preferable. Therefore, it is preferable that there is no high resistance film except for a portion where insulation is desired.

  From this point of view, it is desirable that the high resistance layer is present at least in the resin seal portion on the tab surface (the position of the cross section in FIG. 1B). By setting a high resistance layer at least on the resin seal portion 20 on the surface of the tab metal, both the insulation of the tab portion and the effect of increasing the seal strength of the tab portion can be achieved. The resin here means a resin layer 19c between the metal layer and the tab of the polymer metal composite film 19 which is an exterior material, as shown in FIG. 1 (c). The resin layer 19 may be one layer, but may be two or more layers. As shown in FIGS. 1B and 1C, the polymer metal composite film 19 which is an exterior material has three layers of a skin resin layer 19a, an exterior metal layer 19b, and a metal layer-tab resin layer 19c. However, the present invention is not limited to this, and a polymer metal composite film used for a conventionally known battery exterior material can be used.

Furthermore, in the present invention, it is more preferable to provide a high resistance layer in a portion close to the seal portion 20 among the tabs taken out from the battery. This is because, as shown in FIG. 1B, the metal layer in the exterior material is exposed to the outside at the end of the battery exterior material, so that the tab vibrates or is bent at the time of attachment. This is because there is a possibility that the tab and the metal layer exposed to the outside may come close to or contact each other, and even in such a case, sufficient insulation can be secured. As a measure for exposing the metal layer at the outer edge of the battery, in the case of a battery for consumer use, it is sufficient to insulate the outer edge of the battery with insulating tape or insulating paint. In the case of a voltage, it can be said that it is necessary to cope with the high insulating layer of the present invention because the insulation cannot be sufficiently ensured as with the above-described seal portion by itself.

  Further, the high resistance layer 21 may be at least one layer, and if it is two or more layers, a further insulating effect can be obtained. In addition, the high resistance film on the metal surface of the tab has an insulating effect even if it is thin, and is particularly effective when it is desired to suppress the thickness of the tab portion.

  Examples of the high resistance layer 21 provided on the surface of the tab metal include a metal oxide film, an insulating plating film, and a resin coating film, but a film having a resistance higher than that of the tab metal (hereinafter simply referred to as a high resistance layer). In order to achieve the object of the invention, there is no particular limitation.

  Preferably, the high resistance layer is a metal oxide film. This is because the resistance value of the film, the anchor effect due to the fine uneven shape on the surface of the film, the bonding strength with the tab metal, the workability, the economical efficiency and the like are excellent. Examples of such metal oxide films include anodic oxide films such as aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony, but should not be limited to these. Embodiments of these metal anodic oxide films include (1) forming these metals as tabs and forming an anodic oxide film on the surface thereof, and (2) forming the anodic oxide films on the surfaces of aluminum and nickel tabs. There is a form in which an anodic oxide film is formed after plating, vapor deposition, or the like.

  The metal oxide film is formed on the tab metal surface by placing the target metal plate (including the target metal plated and evaporated on the surface of the metal plate) in an acidic liquid such as sulfuric acid and using it as the anode. A stable metal plate (Pt or the like) or the same metal as the anode is used as a cathode, a voltage of about 20 V is applied, and electrolysis is performed for about 1 hour. By this method, a fine concavo-convex anodic oxide film can be formed.

  As for the method of forming an insulating plating film on the surface of the tab metal, a conventionally known metal surface such as a CVD method, a PVD method, a vacuum deposition method, a hot dipping method, a metal penetration method, a metal spraying method, an electrolytic plating, etc. It can be formed using processing techniques. The insulating plating material used for forming the insulating plating film is not particularly limited as long as it can be a high resistance film, and examples thereof include magnetic ferrite (insulating oxide) plating.

Similarly, a method for forming a film by resin coating can also be formed by using a conventionally known resin coating technique. For example, as shown in Working Example 10, in addition to a method in which the powder of the resin to be coated is uniformly attached to the tab surface by electrostatic powder coating, and then baked at a high temperature, an immersion method, electrostatic powder The film may be formed by coating the resin using a spray method other than the painting method, or the film may be formed by baking the coated resin, which should not be particularly limited. Absent. Preferably, the electrostatic powder coating method used in the examples is excellent in terms of the bonding strength between the resin and the metal, and the anchor effect due to the formation of fine irregularities on the surface of the resin film. The resin used for forming the resin coating film is not particularly limited as long as it can be a high resistance film. For example, Teflon (registered trademark) (tetrafluoroethylene produced by DuPont, USA) Trade name of resin), polycarbonate (PC), polyester (PETP), ethylene trifluoride chloride (PCTFE)
And tetrafluoroethylene / hexafluoropropylene (FEP), vinylidene fluoride (PVdF), and the like.

The resistance value of the high resistance layer (film) is 10 ⁶ V / m or more, preferably 2 × 10 ⁷ V / m or more in order to ensure insulation of the tab portion of the high voltage bipolar battery. desirable. If the resistance value of the high-resistance film is smaller than 10 ⁶ V / m, there is a possibility that the rate of insulation decrease will increase in the case of a high voltage used in a vehicle. The upper limit of the working voltage in a vehicle is generally about 500V. Accordingly, it is necessary to ensure insulation even when 500 V is applied between the tab and the metal layer in the exterior film. From this point of view, the resistance value is derived. The resistance (value) of the high resistance film is a dielectric breakdown strength expressed in units of V / m as described above. This dielectric breakdown strength can be determined by a measuring method based on ASTM D149, JIS K6911, and JIS C2103, and indicates a voltage that can be withstood by a substance per unit length. The higher this value, the more effective the insulation can be ensured even with a thin material because it is possible to insulate the high voltage applied to both ends of the material in the thickness direction.

  Further, it is desirable that the resistance value between the tab having the high resistance layer and the metal layer in the exterior material is 100 MΩ or more, preferably 500 MΩ or more when 500 V is applied. The resistance value is obtained by the method described in “Insulation test” described in the examples. If the resistance value between the tab and the metal layer in the exterior material is 100 MΩ or more, it can be said that insulation is secured even when 500 V is applied between the tab and the metal layer in the exterior film. In addition, by measuring the resistance value after the battery is completed, it is effective not only for confirming insulation between the tab and the metal layer in the exterior material, but also for confirming that there is no abnormality such as a short circuit inside the battery. It can also be a simple inspection means.

  The film thickness of the high resistance layer (film) is not particularly limited as long as the object of the invention can be achieved as long as the resistance value is higher than the resistance of the tab metal. Also, a suitable film for the high resistance layer (film) depending on the magnitude of the resistance value determined by the battery voltage, the thickness and insulation performance of the metal layer-tab resin layer 19c, the resistance value of the film material, and the like. Since the thickness range is different, it cannot be uniquely defined, but a sufficient insulation can be ensured even with a submicron thickness of usually 5 μm or less, preferably 0.1 to 1 μm.

The range of the specific surface area of the high resistance layer is desirably 1.1-5. Here, the specific surface area of the high resistance layer is, as shown in FIG. 2, the actual area with respect to the projected area (surface area of the high resistance film) in the portion of the tab 11 where the film 21 of the high resistance layer is provided. It can be said. That is, the specific surface area = the surface area of the film / the projected area. Actually, the specific surface area is calculated by the method described in “Measurement of specific surface area” described in Examples, and is the ratio of the gas adsorption amount of the tab after film formation to the gas adsorption amount of the tab before film formation. Can be prescribed. Briefly, specific surface area, measured by the gas adsorption method conforming to JIS Z8830, the adsorption amount of free tab of film to (m ² / g), the adsorption amount after forming a film (m ² / g ) And the ratio is shown. The larger the specific surface area is, the larger the adhesion area and the greater the anchoring effect. However, when the specific surface area of the tab portion of the present invention is too large to exceed 5, as shown in FIG. The uneven shape of the high resistance film 21 becomes too fine, and the substantial anchor is reduced. In addition, when the specific surface area is less than 1.1, the amount of unevenness of the film 21 is small, so that the improvement of the adhesive strength with the exterior material is small. Therefore, the adhesive effect which was excellent in the range of 1.1-5 is brought about. The uneven shape and film thickness of the high resistance film 21 can be adjusted and controlled by changing the anodic oxide film conditions, insulating plating film conditions, resin coating conditions, etc. at the manufacturing stage, although it depends on the type of film. Thus, the desired specific surface area can be easily controlled. The above specific surface area requirement is preferably satisfied when the high-resistance layer is a metal oxide film. Since the specific surface area is a desirable requirement for increasing the adhesive strength between the high-resistance layer coating and the resin film of the exterior material, for example, when the high-resistance layer is a coating by resin coating as shown in Example 10 Even if the specific surface area is 1 (that is, even if there is no fine uneven shape on the surface of the film by the resin coating), it is the adhesion between the resins, so that sufficient adhesive strength can be secured (Table 1). (See Peel average value). Therefore, in the present invention, there are cases where sufficient adhesive strength can be provided even if the high resistance layer is outside the range of the specific surface area defined above.

  From this viewpoint, the average peel value (A) between the high resistance layer of the tab and the exterior material, and the average peel value (B) between the base material (tab without the high resistance layer) and the exterior material, The ratio (A / B × 100 (%)) exceeds 100%, preferably 200% or more, more preferably 500% or more. The peel average value is determined by the method described in “Measurement of peel average value” described in Examples. Briefly, the tensile test is based on JIS K6253, and the tab and the film are subjected to a 180 ° tensile test, and the peel strength and length at that time are measured. When the result is graphed as shown in FIG. 2, the average value of the trapezoidal ridges of the graph of peel strength is defined as the peel average value, and the peel average value of the conventional structure shown in FIG. It can obtain | require as an intensity | strength ratio from the peel average value calculated | required from the tension test result between the tab which does not provide the high resistance layer, and an exterior material.

  For example, taking the result of a tensile test for measuring the adhesive strength of the tab portion shown in FIG. 2 as an example, the tensile strength for measuring the adhesive strength of the tab portion having an aluminum oxide film obtained by the method described in Example 1 is used. A graph of the results of the test is the graph of “Invention Structure” in FIG. A graph of the “conventional structure” in FIG. 2 is a graph of the results of a tensile test in the absence of a film. From this result, it can be confirmed that the inventive structure has a large absolute value of peel strength (tensile strength) and can withstand strong tearing force. Furthermore, the regulation based on the strength ratio of the peel average value obtained from these graphs is advantageous in that the adhesive strength can be evaluated regardless of the type of the film of the high resistance layer.

Further, it can be said that the high resistance layer is particularly preferably an aluminum oxide film. This is because the best mode in actual use is an oxide film of aluminum. Specifically, the anodized film of aluminum is an insulating film having a porous hole, and generally exhibits a high resistance value of 10 ⁹ V / m and exhibits a high anchor effect. Further, when the tab material is aluminum, an oxide film may be formed as it is, and in the case of a metal other than aluminum, it is advantageous in that a film can be formed thereon after plating and vapor deposition of aluminum. It is. The method for producing the anodized film of aluminum is as follows. A high-purity aluminum plate is immersed in a 1M sulfuric acid aqueous solution to form an anode, a large-sized aluminum plate is used as the negative electrode, a DC power supply is used, and an output voltage is set to 20 V or higher. In this state, electrolysis is performed for 30 minutes or more. The obtained anodic oxide film is left by leaving only the adhesion part (seal part) with the exterior material, and the other part is obtained by scraping the oxide film to reduce contact resistance (this manufacturing method was applied to Example 1). .

  In the present invention, at least one or more resistance layers (high resistance layers) higher than the metal resistance of the tab metal may be provided between the metal layers in the polymer metal composite film that is the tab and the exterior material. It can be said. That is, although it is practically excellent to have a high resistance layer on the metal surface of the tab, an embodiment having a high resistance layer on the polymer metal composite film side is not excluded.

  The main components of the bipolar battery according to the present invention have been described above. However, the other components of the bipolar battery according to the present invention are not particularly limited, and are configured by appropriately using conventionally known ones. Is something that can be done. Hereinafter, the bipolar lithium ion secondary battery is taken as an example to describe these constituent elements, but it goes without saying that the present invention should not be limited to these.

[Current collector]
The current collector that can be used in the present invention is not particularly limited, and conventionally known current collectors can be used. For example, aluminum foil, stainless steel (SUS) foil, titanium foil, nickel-aluminum clad material, copper-aluminum clad material, SUS-aluminum clad material, or a plating material of a combination of these metals can be preferably used. Further, a current collector in which a metal surface is coated with aluminum may be used. Moreover, you may use the electrical power collector which bonded 2 or more metal foil depending on the case. When the composite current collector is used, as a material for the positive electrode current collector, for example, a conductive metal such as aluminum, an aluminum alloy, SUS, or titanium can be used, and aluminum is particularly preferable. On the other hand, as the material of the negative electrode current collector, for example, conductive metals such as copper, nickel, silver, and SUS can be used, and SUS and nickel are particularly preferable. Further, in the composite current collector, the positive electrode current collector and the negative electrode current collector may be electrically connected to each other directly or via a conductive intermediate layer made of a third material.

  Each thickness of the positive electrode current collector and the negative electrode current collector in the composite current collector may be as usual, and both current collectors are, for example, about 1 to 100 μm. Preferably, the thickness of the current collector (including the composite current collector) is about 1 to 100 μm. However, in order to obtain a high-voltage battery as in the present invention, the cell layer is several tens to hundreds. Since it is desirable to reduce the thickness of the current collector because ten layers are required to be laminated, the thickness of the current collector is preferably in the range of 5 to 20 μm.

[Positive electrode layer (positive electrode active material layer)]
Here, as a constituent material of the positive electrode layer, any material that includes a positive electrode active material may be used, and if necessary, a conductive assistant for increasing electronic conductivity, a binder, and an electrolyte support for increasing ionic conductivity. Salts (lithium salts), polymer electrolytes, additives, and the like may be included, but when a polymer gel electrolyte or liquid electrolyte is used for the electrolyte layer, a conventionally known binder that binds the positive electrode active material fine particles to each other, electronic conductivity It is only necessary to include a conductive additive for increasing the viscosity, and it is not necessary to include a host polymer, an electrolytic solution, a lithium salt, or the like as a raw material for the polymer electrolyte. Even when a liquid electrolyte is used for the electrolyte layer, the positive electrode layer may not contain a host polymer, an electrolytic solution, a lithium salt, or the like as a raw material of the polymer electrolyte.

As the positive electrode active material, a composite oxide of lithium and transition metal (lithium-transition metal composite oxide) can be suitably used. Specifically, Li—Mn composite oxides such as LiMnO ₂ and LiMn ₂ O ₄ , Li—Co composite oxides such as LiCoO _2, and Li—Cr such as Li ₂ Cr ₂ O ₇ and Li ₂ CrO ₄ are used. Li-Ni composite oxides such as LiNiO ₂ , Li-Fe composite oxides such as Li _x FeO _y and LiFeO ₂ , Li-V composite oxides such as Li _x V _y O _z And selected from Li metal oxides, such as those obtained by substituting some of these transition metals with other elements (for example, LiNi _x Co _1-x O ₂ (0 <x <1), etc.) However, the present invention is not limited to these materials. These lithium-transition metal composite oxides are excellent in reactivity and cycle durability and are low-cost materials. Therefore, using these materials for the electrodes is advantageous in that a battery having excellent output characteristics can be formed. In addition, transition metal and lithium phosphate compounds and sulfuric acid 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.

Among the positive electrode active materials, a Li—Mn composite oxide is desirable. This is because by using the Li—Mn-based composite oxide, the profile can be tilted, and the reliability at the time of abnormality is improved. Specifically, the voltage-SOC profile can be tilted by making the positive electrode active material Li-Mn based composite oxide. As a result, the state of charge (SOC) of the battery can be determined by measuring the voltage, so that the battery can detect and deal with a particularly unstable overcharge / overdischarge state. It becomes possible to improve the property. In addition, the Li—Mn-based composite oxide has a mild reaction even when the battery fails due to overcharge or overdischarge, and can be said to have high reliability in an abnormal state. As a result, it becomes easy to detect the voltage of each single cell layer and the entire bipolar.

  In order to reduce the electrode resistance of the bipolar battery, the positive electrode active material may have a particle diameter smaller than that generally used in non-bipolar lithium ion secondary batteries. Specifically, the average particle diameter of the positive electrode active material fine particles is preferably 0.1 to 5 μm. It is desirable that the thickness be in the range of 0.1 to 50 μm, preferably 0.5 to 20 μm, more preferably 0.5 to 5 μm.

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

  As the binder, polyvinylidene fluoride (PVDF), SBR, polyimide, or the like can be used. However, it is not necessarily limited to these.

  Among the above electrolytes, the polymer gel electrolyte is a solid polymer electrolyte having ion conductivity containing an electrolyte used in a lithium ion secondary battery that is not bipolar type. A polymer skeleton that does not have the same electrolyte solution is also included. Therefore, the polymer solid electrolyte among the electrolytes is a polymer solid electrolyte having ion conductivity.

Here, the electrolytic solution (electrolyte salt and plasticizer) contained in the polymer gel electrolyte is not particularly limited, and various conventionally known electrolytic solutions can be appropriately used. For example, inorganic acid anion salts such as LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiTaF ₆ , LiAlCl ₄ , Li ₂ B ₁₀ Cl ₁₀ , LiBOB (lithium bisoxide borate), LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, at least one selected from organic acid anion salts such as Li (C ₂ F ₅ SO ₂ ) ₂ N (lithium bis (perfluoroethylenesulfonylimide); also called LiBETI) Cyclic carbonates such as propylene carbonate and ethylene carbonate, including lithium salts (electrolyte salts); chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1 , 2-dimethoxyethane, Selected from among ethers such as 1,2-dibutoxyethane; lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; methyl acetate and methyl formate The thing using the plasticizer (organic solvent), such as an aprotic solvent, which mixed 1 type or 2 types or more from at least can be used. However, it is not necessarily limited to these.

  Examples of the solid polymer electrolyte having ion conductivity include known solid polymer electrolytes such as polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

For example, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), etc. are used as the polymer having no lithium ion conductivity used in the polymer gel electrolyte. it can. However, it is not necessarily limited to these. Note that PAN, PMMA, etc. are in a class that has almost no ionic conductivity, and thus can be a polymer having the above ionic conductivity, but here, they are used for a polymer gel electrolyte. This is exemplified as a polymer having no lithium ion conductivity.

The ion as the conducting electrolyte supporting salts to improve 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 A salt, an organic acid anion salt such as Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, or a mixture thereof can be used. However, it is not necessarily limited to these.

  The ratio (mass ratio) between the host polymer and the electrolytic solution in the polymer gel electrolyte may be determined according to the purpose of use, but is in the range of 2:98 to 90:10. That is, the leakage of the electrolyte from the electrolyte material in the battery electrode can be effectively sealed by forming the insulating layer 7 as shown in FIG. Therefore, it is possible to give priority to battery characteristics relatively with respect to the ratio (mass ratio) between the host polymer and the electrolytic solution in the polymer gel electrolyte.

  Examples of the additive include trifluoropropylene carbonate for enhancing battery performance and life, and various fillers as reinforcing materials.

  The thickness of the positive electrode layer (positive electrode active material film thickness) is not particularly limited, and is determined in consideration of the intended use of the battery (emphasis on output, emphasis on energy, etc.) and ion conductivity, as described for the blending amount. However, it should be determined in consideration of the intended use of the battery (emphasis on output, energy, etc.) and ion conductivity. Therefore, the thickness of the positive electrode layer (positive electrode active material film thickness) is about 1 to 500 μm. In order to obtain a high-voltage battery as in the present invention, it is necessary to stack several tens to hundreds of single battery layers, and it is desirable to reduce the thickness of the electrode. The material thickness is preferably in the range of 5 to 30 μm.

  The amount of positive electrode active material, conductive additive, binder, polymer electrolyte (host polymer, electrolyte, etc.), lithium salt, etc. in the positive electrode layer depends on the intended use of the battery (output priority, energy priority, etc.), ion conductivity Should be taken into consideration.

[Negative electrode layer (negative electrode active material layer)]
The negative electrode layer includes a negative electrode active material active material. In addition to this, a conductive auxiliary agent for increasing electronic conductivity, a binder, a polymer electrolyte (host polymer, electrolytic solution, etc.), a lithium salt for increasing ionic conductivity, an additive, etc. may be included. When a polymer gel electrolyte is used for the molecular electrolyte layer, it only needs to contain a conventionally known binder that binds the negative electrode active material fine particles to each other, a conductive auxiliary agent for increasing electronic conductivity, and the like. The host polymer, electrolyte solution, lithium salt and the like may not be contained. Even when a solution electrolyte is used for the electrolyte layer, the negative electrode layer may not contain a host polymer, an electrolytic solution, a lithium salt, or the like as a raw material of the polymer electrolyte. Except for the type of the negative electrode active material, the contents are basically the same as those described in the section “Positive electrode layer”, 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. Specifically, carbon, metal compounds, metal oxides, Li metal compounds, Li metal oxides (including lithium-transition metal composite oxides), boron-added carbon, graphite, and the like can be used. These may be used alone or in combination of two or more. Examples of the carbon include conventionally known carbon materials such as graphite carbon, hard carbon, and soft carbon. Examples of the metal compound include LiAl, LiZn, Li ₃ Bi, Li ₃ Cd, Li ₃ Sd, Li ₄ Si, Li _4.4 Pb, Li _4.4 Sn, Li _0.17 C (LiC ₆ ), and the like. The metal _{oxides, SnO, SnO 2, GeO,} GeO 2, In 2 O, In 2 O 3, PbO, PbO 2, Pb 2 O 3, Pb 3 O 4
, Ag ₂ O, AgO, Ag ₂ O ₃ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , SiO, ZnO, CoO, NiO, FeO and the like. Examples of the Li metal compound include Li ₃ FeN ₂ , Li _2.6 Co _0.4 N, Li _2.6 Cu _0.4 N, and the like. Examples of the Li metal oxide (lithium-transition metal composite oxide) include a lithium-titanium composite oxide represented by Li _x Ti _y O _z such as Li ₄ Ti ₅ O ₁₂ . Examples of the boron-added carbon include boron-added carbon and boron-added graphite. However, in this invention, it should not be restrict | limited to these but a conventionally well-known thing can be utilized suitably. The boron content in the boron-added carbon is preferably in the range of 0.1 to 10% by mass, but should not be limited to this.

  Among the negative electrode active materials, those selected from a crystalline carbon material and an amorphous carbon material are preferable. By using these, the profile can be tilted. Specifically, the voltage-SOC profile can be tilted by selecting the negative electrode active material from a crystalline carbon material or an amorphous carbon material. As a result, the state of charge (SOC) of the battery can be determined by measuring the voltage, so that the battery can detect and deal with a particularly unstable overcharge / overdischarge state. It becomes possible to improve the property. This effect is particularly remarkable in amorphous carbon and is effective but not particularly limited. As a result, it becomes easy to detect the voltage of each single cell layer and the entire bipolar. The crystalline carbon material here refers to a graphite-based carbon material, and includes the above-described graphite carbon and the like. The non-crystalline carbon material refers to a hard carbon-based carbon material, and includes the hard carbon and the like.

  The thickness of the negative electrode layer (negative electrode active material film thickness) is not particularly limited, and is determined in consideration of the intended use of the battery (emphasis on output, emphasis on energy, etc.) and ion conductivity, as described for the blending amount. However, it should be determined in consideration of the intended use of the battery (emphasis on output, energy, etc.) and ion conductivity. Therefore, the thickness of the negative electrode layer (negative electrode active material film thickness) is about 1 to 500 μm. In order to obtain a high-voltage battery as in the present invention, it is necessary to stack several tens to hundreds of single battery layers, and it is desirable to reduce the thickness of the electrode. The material thickness is preferably in the range of 5 to 30 μm.

[Electrolyte layer]
In the present invention, either (a) a polymer gel electrolyte, (b) a polymer solid electrolyte, or (c) a separator impregnated with these polymer electrolyte or electrolyte (including a nonwoven fabric separator), depending on the purpose of use. It can also be applied to.

(A) Polymer gel electrolyte The polymer gel electrolyte is not particularly limited, and those used in conventional gel electrolyte layers can be appropriately used. Here, the gel electrolyte refers to one in which an electrolytic solution is held in a polymer matrix. In the present invention, the difference between an all solid polymer electrolyte (also simply referred to as a polymer solid electrolyte) and a gel electrolyte is as follows.

  A gel electrolyte is an all-solid polymer electrolyte such as polyethylene oxide (PEO) containing an electrolytic solution used in a normal lithium ion battery.

  A gel electrolyte is a polymer electrolyte such as polyvinylidene fluoride (PVDF) in which a polymer skeleton having no lithium ion conductivity is held.

  -The ratio of the polymer constituting the gel electrolyte (also referred to as host polymer or polymer matrix) to the electrolytic solution is wide. When 100% by mass of the polymer is the total solid polymer electrolyte and 100% by mass of the electrolytic solution is the liquid electrolyte, the intermediate All bodies are gel electrolytes.

  A host polymer of the gel electrolyte is not particularly limited, and a conventionally known one can be used. Preferably, polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG ), Polyacrylonitrile (PAN), polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), poly (methyl methacrylate) (PMMA) and copolymers thereof are preferable, and the solvents include ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (GBL), dimethyl carbonate (DMC), diethyl carbonate (DEC), and mixtures thereof are preferred.

The electrolyte solution (electrolyte salt and plasticizer) of the gel electrolyte is not particularly limited, and conventionally known ones can be used. Specifically, as long as usually used in a lithium ion battery, 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 At least one lithium salt (electrolyte salt) selected from organic acid anion salts such as a salt, LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N ), 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; γ-butyrolactone, etc. Kutons; Nitriles such as acetonitrile; Esters such as methyl propionate; Amides such as dimethylformamide; Aprotic solvents in which at least one selected from methyl acetate and methyl formate is mixed. The thing using organic solvents (plasticizer), such as these, can be used. However, it is not necessarily limited to these.

  The ratio of the electrolytic solution in the gel electrolyte in the present invention is not particularly limited, but is preferably about several mass% to 98 mass% from the viewpoint of ionic conductivity. The present invention is particularly effective for a gel electrolyte having a large amount of electrolytic solution in which the proportion of the electrolytic solution is 70% by mass or more.

  In the present invention, the amount of the electrolyte contained in the gel electrolyte may be substantially uniform inside the gel electrolyte, or may be decreased in an inclined manner from the central portion toward the outer peripheral portion. . The former is preferable because reactivity can be obtained in a wider range, and the latter is preferable in that the sealing property of the all solid polymer electrolyte portion in the outer peripheral portion with respect to the electrolytic solution can be improved. When decreasing gradually from the central part toward the outer peripheral part, polyethylene oxide (PEO), polypropylene oxide (PPO) and copolymers thereof having lithium ion conductivity are used as the host polymer. It is desirable.

(B) Polymer solid electrolyte The all solid polymer electrolyte is not particularly limited, and a conventionally known one can be used. Specifically, it is a layer composed of a polymer having ion conductivity, and the material is not limited as long as it exhibits ion conductivity. Examples of the all solid polymer electrolyte include known solid polymer electrolytes such as polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. The solid polymer electrolyte contains a lithium salt in order to ensure ionic conductivity. As the lithium 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. Polyalkylene oxide polymers 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.

(C) Separator (including non-woven fabric separator) impregnated with the polymer electrolyte or electrolytic solution (electrolyte salt and plasticizer)
As the electrolyte that can be impregnated in the separator, the same electrolyte (electrolyte salt and plasticizer) solution as described in (a) and (b) or (a) described above can be used. The description in is omitted.

  The separator is not particularly limited, and a conventionally known separator can be used. For example, a porous sheet made of a polymer that absorbs and holds the electrolyte (for example, a polyolefin microporous separator). Etc.) can be used. The polyolefin microporous separator having the property of being chemically stable to an organic solvent has an excellent effect that the reactivity with the electrolyte (electrolytic solution) can be kept low.

  Examples of the polymer material include polyethylene (PE), polypropylene (PP), a laminate having a three-layer structure of PP / PE / PP, and polyimide.

  The thickness of the separator cannot be unambiguously defined because it varies depending on the intended use. However, in the case of a secondary battery for driving a motor such as an electric vehicle (EV) or a hybrid electric vehicle (HEV), a single layer is used. Or it is desirable that it is 4-60 micrometers in a multilayer. The mechanical strength in the thickness direction is desirable because the thickness of the separator is within such a range, and it is desirable to narrow the gap between the electrodes for high output and prevention of short-circuiting caused by fine particles entering the separator. And there is an effect of ensuring high output performance. In addition, when a plurality of batteries are connected, the electrode area increases, so that it is desirable to use a thick separator in the above range in order to increase the reliability of the battery.

  The fine pore diameter of the separator is desirably 1 μm or less (usually a pore diameter of about several tens of nm). Due to the fact that the average diameter of the micropores in the separator is within the above range, the “shutdown phenomenon” that the separator melts due to heat and the micropores close quickly occurs, resulting in higher reliability during abnormalities, resulting in heat resistance. Has the effect of improving. In other words, when the battery temperature rises due to overcharging (in an abnormal state), the “shutdown phenomenon” that the separator melts and closes the micropores occurs quickly, so that the positive electrode (+) of the battery (electrode) Li ions cannot pass through to the negative electrode (−) side, and no further charge is possible. As a result, overcharging cannot be performed and overcharging is eliminated. As a result, the heat resistance (safety) of the battery is improved, and it is possible to prevent gas from being released and the heat fusion part (seal part) of the battery exterior material from being opened. Here, the average diameter of the micropores of the separator is calculated as an average diameter obtained by observing the separator with a scanning electron microscope or the like and statistically processing the photograph with an image analyzer or the like.

  The separator preferably has a porosity of 20 to 50%. The separator's porosity is within the above range, preventing output from being reduced due to the resistance of the electrolyte (electrolyte), and preventing the short circuit caused by fine particles penetrating the separator's pores (micropores). It has the effect of securing both sexes. Here, the porosity of the separator is a value obtained as a volume ratio from the density of the raw material resin and the density of the separator of the final product.

  The amount of electrolyte impregnated into the separator may be impregnated up to the holding capacity range of the separator, but may be impregnated beyond the holding capacity range. This can be impregnated as long as it can be retained in the electrolyte layer because a seal portion is provided in the electrolyte and the electrolyte solution can be prevented from exuding from the electrolyte layer.

The nonwoven fabric separator used for holding the electrolyte is not particularly limited, and can be manufactured by entwining the fibers into a sheet. Moreover, the spun bond etc. which are obtained by fusing fibers by heating can also be used. In other words, it may be in the form of a sheet formed by arranging fibers in a web (thin cotton) shape or mat shape by an appropriate method, and joining them using an appropriate adhesive or the fusing force of the fibers themselves. The adhesive is not particularly limited as long as it has sufficient heat resistance at the temperature during manufacture and use, and is stable without any reactivity or solubility with respect to the gel electrolyte. In addition, conventionally known ones can be used. In addition, the fiber used is not particularly limited, and for example, conventionally known fibers such as cotton, rayon, acetate, nylon, polyester, polypropylene, polyethylene such as polyethylene, polyimide, and aramid can be used. Depending on (such as mechanical strength required for the electrolyte layer), they are used alone or in combination. Further, the bulk density of the nonwoven fabric is not particularly limited as long as sufficient battery characteristics can be obtained by the impregnated polymer gel electrolyte. That is, if the bulk density of the nonwoven fabric is too large, the proportion of the non-electrolyte material in the electrolyte layer becomes too large, which may impair the ionic conductivity in the electrolyte layer.

  The porosity of the nonwoven fabric separator is preferably 50 to 90%. If the porosity is less than 50%, the electrolyte retention deteriorates, and if it exceeds 90%, the strength is insufficient. Furthermore, the thickness of the nonwoven fabric separator may be the same as that of the electrolyte layer, preferably 5 to 200 μm, particularly preferably 10 to 100 μm. When the thickness is less than 5 μm, the electrolyte retention deteriorates, and when it exceeds 200 μm, the resistance increases.

  In addition, you may use together the electrolyte layer of said (1)-(3) in one battery.

  In addition, the polymer electrolyte may be contained in the electrolyte layer, the positive electrode active material layer, and the negative electrode active material layer, but the same polymer electrolyte may be used, or different polymer electrolytes may be used depending on the layer.

  By the way, a host polymer for a polymer electrolyte that is preferably used at present is a polyether polymer such as PEO and PPO. For this reason, the oxidation resistance on the positive electrode side under high temperature conditions is weak. Therefore, when using a positive electrode agent having a high oxidation-reduction potential that is generally used in a solution-type lithium ion battery, the capacity of the negative electrode is preferably smaller than the capacity of the positive electrode facing through the polymer electrolyte layer. . If the capacity of the negative electrode is less than the capacity of the opposing positive electrode, it is possible to prevent the positive electrode potential from rising excessively at the end of charging. In addition, the capacity | capacitance of a positive electrode and a negative electrode can be calculated | required from manufacturing conditions as theoretical capacity | capacitance at the time of manufacturing a positive electrode and a negative electrode. You may measure the capacity | capacitance of a finished product directly with a measuring device.

  However, if the capacity of the negative electrode is smaller than the capacity of the opposing positive electrode, the negative electrode potential will be too low and the durability of the battery may be impaired, so it is necessary to pay attention to the charge / discharge voltage. For example, care should be taken not to lower the durability by setting the average charge voltage of one cell (single cell layer) to an appropriate value for the oxidation-reduction potential of the positive electrode active material.

  The thickness of the electrolyte layer constituting the battery is not particularly limited. However, in order to obtain a compact bipolar polymer battery, it is preferable to make it as thin as possible as long as the function as an electrolyte can be secured. The thickness of a general electrolyte layer is 5 to 200 μm, preferably about 10 to 100 μm.

[Insulation layer]
Insulating layers are used around the electrodes in order to prevent liquid junctions due to electrolytes, contact between adjacent current collectors in the battery, and short-circuiting due to slight irregularities at the ends of the laminated electrodes. It is formed. In this invention, you may provide an insulating layer around an electrode as needed. This means that when used as a vehicle drive or auxiliary power source, even if a solid electrolyte is used to completely prevent a short circuit due to electrolyte (liquid drop), the vibration and impact on the battery will last for a long time. Be loaded. Therefore, from the viewpoint of prolonging battery life, it is desirable to install an insulating layer in order to ensure longer-term reliability and safety, and to provide a high-quality, large-capacity power supply. .

  As the insulating layer, any insulating layer may be used as long as it has insulating properties, sealing performance against falling off of the solid electrolyte, sealing performance against moisture permeation from the outside (sealing performance), heat resistance under battery operating temperature, etc. Epoxy resin, rubber, polyethylene, polypropylene, polyimide and the like can be used, but epoxy resin is preferable from the viewpoint of corrosion resistance, chemical resistance, ease of production (film forming property), economy and the like.

[Positive electrode and negative electrode terminal plate]
The positive electrode and the negative electrode terminal plate may be used as necessary. That is, depending on the laminated (or wound) structure of the bipolar battery, the positive electrode and the negative electrode tab (electrode terminal) may be taken out from the outermost current collector directly or through the electrode lead. In this case, the positive electrode and the negative electrode A terminal board may not be used (see FIG. 1B).

  When using positive and negative terminal plates, in addition to having a function as a terminal, it is better to be as thin as possible from the viewpoint of thinning, but the laminated electrode, electrolyte and current collector all have mechanical strength. Since it is weak, it is desirable to have strength to sandwich and support these from both sides. Furthermore, from the viewpoint of suppressing the internal resistance from the electrode terminal plate to the electrode tab, it can be said that the thickness of the positive electrode and the negative electrode terminal plate is usually preferably about 0.1 to 2 mm.

  As the material of the positive electrode and the negative electrode terminal plate, a material used in a lithium ion secondary battery which is not a normal bipolar type can be used. For example, aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof can be used.

  The material of the positive electrode terminal plate and the negative electrode terminal plate may be the same material or different materials. Furthermore, the positive electrode and the negative electrode terminal plate may be a laminate of different materials. Since these positive electrode and negative electrode terminal plates may also be close to or in close contact with the battery outer packaging material, if necessary, a high resistance layer similar to the electrode tab may be provided on the required portion on the outer surface of the electrode terminal plate. Needless to say, it may be provided as appropriate.

[Positive electrode and negative electrode lead]
The positive electrode and the negative electrode lead may be used as necessary. As the positive electrode and the negative electrode lead, a known electrode lead used in a conventional lithium ion secondary battery that is not a bipolar type can be used. For example, aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof can be used. The material of the positive electrode lead and the negative electrode lead may be the same material or different materials. Furthermore, the positive electrode and the negative electrode lead may be formed by stacking different materials. In addition, since these positive and negative electrode leads may also be close to or in close contact with the battery outer packaging material, if necessary, a high resistance layer similar to the electrode tab of the present invention is required on the electrode lead surface. Needless to say, it may be provided appropriately.

[Positive electrode and negative electrode tab (tab or electrode tab)]
As shown in FIG. 1 (b), the positive and negative electrode tabs 11 and 13 used in the present invention are positive and negative electrodes connected to the current collector of the outermost layer electrode (or the electrode terminal plate connected thereto). It may be connected between the leads 15 and 17 and may be connected to a positive / negative terminal plate or positive / negative electrode lead (not shown) connected to the current collector of the outermost layer electrode. A part of the current collector of the outer layer electrode may be formed to be extended (not shown), and is not particularly limited. In addition,
The part taken out from the battery exterior material 19 to the outside of the battery is insulated against heat so that it does not affect the product (for example, automobile parts, especially electronic devices) by contacting with peripheral devices or wiring and leaking electricity. May be covered with a heat-shrinkable tube.

  Moreover, the tab used for this invention can use the well-known electrode tab used with the normal lithium ion secondary battery which is not an existing bipolar type. For example, aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof can be used. The materials of the positive electrode tab and the negative electrode tab may be the same material or different materials. Furthermore, the positive electrode and the negative electrode tab may be formed by stacking multiple layers of metals (including alloys) of different materials.

Moreover, although the metal resistance of the tab metal used as the reference | standard of the high resistance layer (film | membrane) of this invention is based also on the kind of tab metal, it is about 1-50 ohm * m normally, V / for convenience for comparison. In terms of m, it is about 10 ⁻⁷ to 10 ⁻⁶ V / m.

  The thickness of the tab is preferably thinner from the viewpoint of improving the airtightness and waterproofness of the portion sandwiched between the exterior material seal portions, whereas the thickness of the tab is desirable from the viewpoint of reducing electrical resistance. Although it may be determined appropriately according to the purpose of use, it is usually in the range of 50 to 1000 μm, preferably 100 to 300 μm.

  Further, as shown in FIG. 1 (a), the tabs may be taken out from the opposing sides separately, or the positive tabs and the negative tabs may be taken out of the same. Although it is not particularly limited such that the positive electrode tab and the negative electrode tab may be separately extracted from adjacent sides, it is possible to form a battery pack by connecting a plurality of these batteries. 3 and FIG. 4 is convenient because of the wiring and the like. Preferably, as shown in FIG. 1A, the positive electrode tab and the negative electrode tab are separated from the opposite sides separately. It can be said that it is desirable to take out.

[High resistance layer formed on positive electrode and negative electrode tab surfaces]
Since the high resistance layer provided on the tab surface is as described above, the description thereof is omitted here.

[Voltage detection tab]
In the present invention, each cell is provided with a voltage detection tab that detects the voltage of each cell (single cell layer) in the battery and can perform charging and discharging by bypassing the overcharged or overdischarged cell. Is desirable. It is desirable that one end of the voltage detection tab is connected to the current collector of the cell, the other end is taken out to the outside of the battery, and these tabs are connected to a voltage detection / bypass control circuit or the like. Thereby, the fall of the battery performance by the capacity | capacitance variation of each single battery layer inside the battery which has several dozens-hundreds of tens cells (single battery layer) can be suppressed, and battery life can be improved. In particular, when a bipolar battery is used as a power source for a vehicle, reliability and stability are required, so that each bipolar battery and each single battery layer (cell) in the battery function normally. It is necessary to constantly monitor whether or not. For this reason, the voltage of all bipolar batteries (usually an assembled battery in which a plurality of bipolar batteries are connected and mounted in a vehicle as a composite battery in which a plurality of bipolar batteries are connected) and the cells in the battery are constantly monitored and deteriorated. This is because it is desirable to be able to detect the bipolar battery and the cells within the battery.

  In addition, it is convenient to take out the positive electrode tab and the negative electrode tab, which are electrode tabs, and the voltage detection tab from different sides of the battery for the convenience of wiring and the like, and it is desirable from the viewpoint of ensuring the airtightness of the seal portion. .

  Furthermore, since only the voltage for each cell (about 4.2 V) is applied to the voltage detection tab, it is not necessary to form a high resistance layer unlike the electrode tab of the present invention.

  The same material as that of the electrode tab can be used for the voltage detection tab. For example, aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof can be used. Although it is desirable to use the same material for each voltage detection tab, different materials may be used. Furthermore, the voltage detection tab may be a laminate of metals (including alloys) made of different materials.

[Battery exterior materials]
In the present invention, in the same manner as in the past, the waterproof and sealing properties of the battery are ensured, the battery is further reduced in weight, and from the viewpoint of preventing external impact and environmental degradation during use, the battery stack as the battery body is used. A polymer metal composite film is used as a battery exterior material for housing the entire body (or battery winding body). The polymer metal composite film is not particularly limited, and any conventionally known one can be appropriately applied. For example, a metal (including an alloy) such as aluminum, stainless steel, nickel, or copper can be used. A polymer metal composite film in which both surfaces of the layer 19b are covered with a resin layer (skin resin layer 19a, metal layer-between-tab resin layer 19c) of an insulator (preferably heat-resistant insulator) such as a polypropylene film may be used. it can. Examples of the resin layer of the insulator (preferably heat-resistant insulator) include, for example, a polyethylene tetraphthalate film (heat-resistant insulating film), a nylon film (heat-resistant insulating film), a polyethylene film (heat-bonding insulating film), Examples thereof include a polypropylene film (heat fusion insulating film) and the like, and these may be applied to the skin resin layer 19a side and the metal layer-tab inter-tab resin layer 19c side according to the purpose.

  The metal layer 19b is required to be a soft material having heat resistance rather than insulation against high voltage, high barrier property against external oxygen, water vapor and light (such as ultraviolet rays), and excellent strength against bending. Is desirable. The film thickness of the metal layer is not limited as long as the above characteristics can be sufficiently exhibited, and is in the range of 10 to 100 μm, preferably 20 to 50 μm.

  The skin resin layer 19a is not required to have heat fusion properties, and is required to have external insulation, weather resistance, abrasion resistance, barrier properties against external oxygen and water vapor, heat resistance, and the like. A desired material such as polyester (heat-resistant insulating film), nylon film (heat-resistant insulating film), and a laminated film of nylon and polyester may be selected. Moreover, the film thickness of the skin resin layer 19a should just be able to fully express the said characteristic, and is 5-50 micrometers, Preferably it is the range of 10-30 micrometers.

  In the resin layer 19c between the metal layer and the tab, internal insulation, heat-fusibility, chemical resistance (resistance to electrolyte, etc.), barrier properties against oxygen, water vapor, gas generated by charge / discharge, and heat resistance Therefore, a desired material such as a polyethylene film (heat fusion insulating film), a polypropylene film (heat fusion insulation film), or the like may be selected. Moreover, the film thickness of the resin layer 19c between metal layers and tabs should just be able to fully express the said characteristic, and is 10-100 micrometers, Preferably it is the range of 20-50 micrometers.

  The film thickness of the entire polymer metal composite film is not particularly limited as long as it can exhibit the above-described functions required for battery exterior materials, but is usually in the range of 50 to 150 μm, preferably 80 to 120 μm. It is.

In addition, these metal layers, skin resin layers, and metal layer-tab resin layers may be formed by laminating layers of different materials. In addition, as shown in FIG. 1B, when two polymer metal composite films on the upper and lower sides are used by heat-sealing, the material of each layer in the two polymer metal composite films is the same material. You may use and a different material may be used.

  In the present invention, a seal part 20 (see FIGS. 1A and 1B) is formed by joining a part or the whole of the peripheral part by heat fusion using a polymer metal composite film. The battery stack 9 is housed and sealed. In this case, the positive and negative electrode tabs 11 and 13 are formed in a state in which the portions where the high resistance layers 21 of the positive and negative electrode tabs 11 and 13 are formed are sandwiched between the seal portions 20 (heat fusion portions) and insulation is ensured. What is necessary is just to make it the structure where the taking-out part of the front-end | tip of this is exposed to the exterior of the said battery exterior material 19. FIG. In addition, it is preferable to use a polymer metal composite film having excellent thermal conductivity in that heat can be efficiently transmitted from a heat source of an automobile and the inside of the battery can be quickly heated to the battery operating temperature.

  Next, as a use of the bipolar battery of the present invention, for example, as a large-capacity power source such as an electric vehicle (EV), a hybrid electric vehicle (HEV), a fuel cell vehicle and a hybrid fuel cell vehicle, a high energy density and a high output density are used. Therefore, it can be suitably used for a vehicle driving power source and an auxiliary power source that require the above. In this case, it is desirable that the assembled battery is constructed by connecting a plurality of bipolar batteries of the present invention. That is, the bipolar battery of the present invention, in particular, at least two bipolar polymer lithium ion secondary batteries are used, and at least one connection method of parallel connection, series connection, parallel-series connection and series-parallel connection is used. By using the assembled battery and further the composite assembled battery, a high-capacity, high-output power source can be formed. Therefore, it becomes possible to respond to the demand for battery capacity and output for each purpose of use at a relatively low cost. These will be described later.

  Next, as a manufacturing method of the bipolar battery of the present invention, except for the above-described method of manufacturing a high-resistance film, which is a high-resistance layer on the tab surface, using an anodic oxidation method or electrostatic powder coating method. However, it is not particularly limited, and various conventionally known methods can be appropriately used. This will be briefly described below.

(1) Application of positive electrode composition First, an appropriate current collector is prepared. The positive electrode composition is usually obtained as a slurry (positive electrode slurry) and applied to one surface of the current collector.

  The positive electrode slurry is a solution containing a positive electrode active material. Other optional components include conductive additives, binders, polymerization initiators, electrolyte raw materials (polymers or host polymers for solid electrolytes, electrolytes, etc.), supporting salts (lithium salts), other additives, and slurry viscosity adjusting solvents. Included. That is, the positive electrode slurry contains, in addition to the positive electrode active material, a conductive additive, an electrolyte raw material, a supporting salt (lithium salt), a slurry viscosity adjusting solvent, a polymerization initiator, etc., in the same manner as a non-bipolar lithium ion secondary battery. It can be made by mixing the materials optionally contained in a predetermined ratio.

  When a polymer gel electrolyte is used for the electrolyte layer, a polymer gel electrolyte may be used as long as it contains a conventionally known binder that binds the positive electrode active material fine particles, a conductive aid for increasing electronic conductivity, a solvent, and the like. The raw material host polymer, electrolyte, lithium salt, etc. may not be contained. The same applies when a separator impregnated with an electrolytic solution is used as the electrolyte layer.

  Examples of the electrolyte polymer raw material (the host polymer of the polymer gel electrolyte raw material or the polymer raw material of the polymer solid electrolyte) include PEO, PPO, and copolymers thereof, and a crosslinkable functional group ( It preferably has a carbon-carbon double bond). By cross-linking the polymer electrolyte using this cross-linkable functional group, the mechanical strength is improved.

With respect to the positive electrode active material, the conductive additive, the binder, and the lithium salt, the above-described compounds can be used.

  The polymerization initiator needs to be selected according to the compound to be polymerized. For example, examples of the photopolymerization initiator include benzyl dimethyl ketal, and examples of the thermal polymerization initiator include azobisisobutyronitrile, t-hexylperoxypiparate, and the like. is not.

  The slurry viscosity adjusting solvent such as NMP is selected according to the type of slurry for positive electrode.

  The addition amount of the positive electrode active material, the lithium salt, and the conductive additive may be adjusted according to the purpose of the bipolar battery, and may be added in a commonly used amount. The addition amount of the polymerization initiator is determined according to the number of crosslinkable functional groups contained in the polymer raw material. Usually, it is about 0.01-1 mass% with respect to a polymeric raw material.

(2) Formation of positive electrode layer The current collector coated with the positive electrode slurry is dried to remove the contained solvent. At the same time, depending on the positive electrode slurry, the cross-linking reaction may be advanced to increase the mechanical strength of the polymer solid electrolyte. For drying, a vacuum dryer or the like can be used. The drying conditions are determined according to the applied positive electrode slurry and cannot be uniquely defined, but are usually 40 to 150 ° C. and 5 minutes to 20 hours.

(3) Application of negative electrode composition A negative electrode composition (negative electrode slurry) containing a negative electrode active material is applied to the surface opposite to the surface on which the positive electrode layer is applied.

  The negative electrode slurry is a solution containing a negative electrode active material. As other components, a conductive additive, a binder, a polymerization initiator, a polymer for a solid electrolyte or a host polymer, an electrolytic solution, a supporting salt (lithium salt), a slurry viscosity adjusting solvent, and the like are optionally included. Since the raw materials used and the amounts added are the same as those described in the section “(1) Application of positive electrode composition”, the description thereof is omitted here.

(4) Formation of negative electrode layer The current collector coated with the negative electrode slurry is dried to remove the contained solvent. At the same time, depending on the slurry for the negative electrode, the crosslinking reaction may be advanced to increase the mechanical strength of the polymer gel electrolyte. This work completes the bipolar electrode. For drying, a vacuum dryer or the like can be used. The drying conditions are determined according to the applied slurry for negative electrode and cannot be uniquely defined, but are usually 40 to 150 ° C. and 5 minutes to 20 hours. By this drying treatment, a negative electrode layer is formed on the current collector.

(5) Formation of electrolyte layer When a polymer solid electrolyte layer is used, for example, by curing a solution prepared by dissolving a polymer solid electrolyte raw material polymer, lithium salt, etc. in a solvent such as NMP. Manufactured. In the case of using a polymer gel electrolyte layer, for example, as a raw material for the polymer gel electrolyte, a pregel solution composed of a host polymer and an electrolytic solution, a lithium salt, a polymerization initiator and the like is simultaneously heated and dried in an inert atmosphere. It is produced by polymerizing (accelerating the crosslinking reaction). Further, when using a polymer gel electrolyte layer in which a polymer gel electrolyte is held in a nonwoven fabric separator, for example, as a raw material for the polymer gel electrolyte, a host polymer and an electrolytic solution, a lithium salt, a polymerization initiator are used in the separator. It is produced by impregnating a pregel solution composed of, etc., and polymerizing (accelerating the crosslinking reaction) simultaneously with heat drying in an inert atmosphere. In the case of using a polymer solid electrolyte layer in which a solid polymer electrolyte is held in a nonwoven fabric separator, for example, as a raw material for the polymer solid electrolyte, a host polymer and an electrolytic solution, a lithium salt, a polymerization initiator, etc. It is produced by impregnating a solution obtained by dissolving in a viscosity modifier and polymerizing (accelerating the crosslinking reaction) simultaneously with heat drying in an inert atmosphere. In addition, when using a liquid electrolyte layer in which an electrolyte is held in a separator, the separator may be impregnated with the electrolyte, for example, after laminating the separator and the bipolar electrode before impregnation with the electrolyte, Each separator may be impregnated.

  For example, the prepared solution or pregel solution is applied onto the positive electrode layer and / or the negative electrode layer of the electrode, and an electrolyte layer having a predetermined thickness or a part thereof (an electrolyte film having about half the electrolyte layer thickness) Form. Then, the electrode on which the electrolyte layer (film) is laminated is cured or heated and dried in an inert atmosphere and polymerized (accelerating the crosslinking reaction), thereby increasing the mechanical strength of the electrolyte and producing the electrolyte layer (film). A film is formed (completed).

  Alternatively, an electrolyte layer laminated between the electrodes or a part thereof (an electrolyte membrane having about half the electrolyte layer thickness) is prepared. The polymer gel electrolyte layer (membrane) in which the polymer gel electrolyte is held in an electrolyte layer (membrane) or separator is prepared by applying the above solution or pregel solution on a suitable film such as a polyethylene terephthalate (PET) film. It is produced by polymerizing (accelerating the crosslinking reaction) simultaneously with curing or heat drying in an active atmosphere, or impregnated with the above-mentioned solution or pregel solution in a suitable non-woven separator such as polypropylene (PP) It is produced by polymerizing (accelerating the crosslinking reaction) simultaneously with curing or heat drying in an atmosphere.

  For curing or heat drying, a vacuum dryer (vacuum oven) or the like can be used. The conditions for heat drying are determined according to the solution or the pregel solution and cannot be uniquely defined, but are usually 30 to 110 ° C. and 0.5 to 12 hours.

  The thickness of the electrolyte layer (film) can be controlled using a spacer or the like. In the case of using a photopolymerization initiator, it is poured into a light transmissive gap, irradiated with ultraviolet rays using an ultraviolet irradiation device capable of drying and photopolymerization, and the polymer in the electrolyte layer is photopolymerized to carry out a crosslinking reaction. It is good to advance and form a film. However, it is needless to say that the method is not limited to this. Depending on the type of polymerization initiator, radiation polymerization, electron beam polymerization, thermal polymerization, etc. are used properly.

  In addition, since the film used above may be heated to about 80 ° C. in the production process, it has sufficient heat resistance at the temperature and has no reactivity with the solution or the pregel solution, and the production process. For example, polyethylene terephthalate (PET) or polypropylene film can be used, but it should not be limited to these.

  The width of the electrolyte layer is often slightly smaller than the current collector size of the bipolar electrode.

  About the composition component of the said solution or pregel solution, its compounding quantity, etc., it should be suitably determined according to the intended purpose.

  The separator soaked with the electrolytic solution has the same structure as the electrolyte layer used in a conventional non-bipolar solution-based bipolar battery, and various known manufacturing methods such as a separator soaked with an electrolytic solution are used. Since it can be manufactured by a method of sandwiching and sandwiching between bipolar electrodes, a vacuum injection method, or the like, detailed description will be omitted below.

(6) Lamination of bipolar electrode and electrolyte layer (i) In the case of a bipolar electrode in which the electrolyte layer (membrane) is formed on one or both sides, the electrolyte layer (membrane) is sufficiently heated and dried under high vacuum. A plurality of the electrodes formed with is cut into a suitable size, and the cut out electrodes are directly bonded together to produce a bipolar battery body (electrode laminate).

    (Ii) When bipolar electrodes and electrolyte layers (membranes) are separately produced, after sufficiently heating and drying under high vacuum, a plurality of bipolar electrodes and electrolyte layers (membranes) are cut into appropriate sizes. . A predetermined number of the cut bipolar electrodes and electrolyte layers (membranes) are bonded together to produce a bipolar battery body (electrode laminate).

  The number of stacked electrode laminates is determined in consideration of battery characteristics required for the bipolar battery. Moreover, the electrode which formed only the positive electrode layer on the electrical power collector is arrange | positioned at the outermost layer by the side of a positive electrode. In the outermost layer on the negative electrode side, an electrode in which only the negative electrode layer is formed on the current collector is disposed. The step of obtaining a bipolar battery by laminating a bipolar electrode and an electrolyte layer (film) or by laminating an electrode having an electrolyte layer (film) is not effective from the viewpoint of preventing moisture from entering the battery. It is preferable to carry out in an active atmosphere. For example, the bipolar battery may be manufactured in an argon atmosphere or a nitrogen atmosphere.

(7) Formation of Insulating Layer In the present invention, for example, the periphery of the electrode forming portion of the electrode laminate is immersed in epoxy resin (precursor solution) or the like with a predetermined width, or the resin is injected or impregnated. In either case, the voltage detection tab, the electrode terminal plate, the electrode lead, the electrode tab, or the current collector portion to which these need to be connected are masked in advance using a releasable masking material or the like. . Thereafter, the epoxy resin is cured to form an insulating portion, and then the masking material is peeled off.

(8) Connection of terminal plate, electrode lead, and tab (terminal) A positive electrode terminal plate and a negative electrode terminal plate are respectively installed on and connected to the current collectors on both outermost layers of the bipolar battery body (battery stack). The positive electrode terminal plate and the negative electrode terminal plate are joined (electrically connected) to the positive electrode lead and the negative electrode lead, and further, the positive electrode tab and the negative electrode tab are joined (electrically connected) (FIG. 1B). See As a method for joining these terminal plates, leads, and tabs, ultrasonic welding having a low joining temperature can be suitably used, but it should not be limited to this, and a conventionally known joining method is appropriately used. can do. Further, in the present invention, the voltage of the single cell layer is detected, and a voltage detection tab that can be bypassed if overcharged or overdischarged is connected to each current collector, and these are connected to the outside of the battery. It is desirable to take out and connect these tabs to a voltage detection and bypass control circuit. Thereby, the fall of the battery performance by the capacity | capacitance variation of each single battery layer inside the battery which has several dozens-hundreds of tens cells (single battery layer) can be suppressed, and battery life can be improved.

(9) Packing (Battery completion)
Finally, in order to prevent external impact and environmental degradation, the entire battery stack is sealed with a battery exterior material to complete a bipolar battery. When sealing, the positive electrode tab, the negative electrode tab, and one end of the voltage detection tab are taken out of the battery.

  Next, in the present invention, at least two or more bipolar batteries can be connected in series, in parallel, or in a mixture of series and parallel to form an assembled battery. This makes it possible to meet the demands for capacity and voltage for various vehicles with a combination of basic bipolar batteries. As a result, it becomes possible to facilitate the design selectivity of required energy and output. Therefore, it is not necessary to design and produce different bipolar batteries for various vehicles, and the basic bipolar battery can be mass-produced, and the cost can be reduced by mass production. Hereinafter, typical embodiments of the assembled battery will be briefly described with reference to the drawings.

  FIG. 3 shows a schematic diagram of an assembled battery (42V1Ah) in which the bipolar battery (24V, 50 mAh) of the present invention is connected in two lines and 20 lines. The tabs in the parallel part were connected by copper bus bars 56 and 58, and the serial part was connected by vibration welding the tabs 11 and 13. The ends of the series part are connected to the terminals 42 and 44 to constitute positive and negative terminals. On both sides of the battery, detection tabs 12 for detecting the voltage of each layer of the bipolar battery 1 are taken out, and their detection lines 53 are taken out at the front part of the assembled battery 50. Specifically, in order to form the assembled battery 50 shown in FIG. 3, five bipolar batteries 1 are connected in parallel by a bus bar 56, and two bipolar batteries 1 connected in parallel are connected in series with two electrode tabs in series. These are stacked in four layers and connected in parallel by a bus bar 58 and housed in a metal assembled battery case 55. In this way, by connecting an arbitrary number of bipolar batteries 1 in series and parallel, an assembled battery 50 that can handle a desired current, voltage, and capacity can be provided. In the assembled battery 50, a positive electrode terminal 42 and a negative electrode terminal 44 are formed at the front side of a metal assembled battery case 55. After the batteries are connected in series and parallel, for example, each bus bar 56 and each positive electrode terminal 42 are connected. The negative terminal 44 is connected to the terminal lead 59. Further, the assembled battery 50 includes a detection tab terminal 54 for monitoring a battery voltage (a voltage of each single cell layer and further a bipolar battery), and a positive electrode terminal 42 and a negative electrode terminal of a metal assembled battery case 55. It is installed in the front part of the side surface in which 44 is provided. All the voltage detection tabs 12 of each bipolar battery 1 are connected to the detection tab terminal 54 via the detection line 53. In addition, an external elastic body 52 is attached to the bottom of the assembled battery case 55, and when a plurality of assembled batteries 50 are stacked to form a composite assembled battery, the distance between the assembled batteries 50 is maintained to prevent vibration. , Impact resistance, insulation, heat dissipation, etc. can be improved.

  The assembled battery 50 may be provided with various measuring devices and control devices in addition to the detection tab terminal 54, depending on the intended use. Furthermore, in order to connect the electrode tabs (11, 13) of the bipolar battery 1 or the detection tab 12 and the detection line 53, ultrasonic welding, heat welding, laser welding, electron beam welding, or a rivet is used. You may make it connect using the bus-bars 56 and 58, or using the crimping method. Furthermore, in order to connect the bus bars 56, 58 and the terminal leads 59, etc., ultrasonic welding, heat welding, laser welding, or electron beam welding may be used.

  The external elastic body 52 may be made of the same material as that of the resin group used in the battery of the present invention, but is not limited thereto.

  In the assembled battery of the present invention, the bipolar battery of the present invention and a battery in which the bipolar battery and the positive and negative electrode materials are the same and the number of structural units of the bipolar battery are connected in series (the non-bipolar type lithium battery). An ion secondary battery) may be connected in parallel. That is, the bipolar battery forming the assembled battery may be a mixture of the bipolar battery of the present invention and a conventional non-bipolar lithium ion secondary battery or the like. As a result, an assembled battery that compensates for each other's weaknesses can be made by combining a bipolar battery that focuses on output and a general lithium ion secondary battery that focuses on energy, and the weight and size of the assembled battery can be reduced. The proportion of each bipolar battery and non-bipolar battery to be mixed is determined according to the safety performance and output performance required for the assembled battery.

FIG. 4 shows an assembled battery in which a bipolar battery A (42 V, 50 mAh) and a general lithium ion secondary battery B (4.2 V, 1 Ah) 10 series (42 V) are connected in parallel. The general battery B and the bipolar battery A have the same voltage, and a parallel connection is formed at that portion. The assembled battery 50 ′ has a structure in which the bipolar battery A has an output sharing and the general battery B has an energy sharing. This is a very effective means in an assembled battery in which it is difficult to achieve both output and energy. Also in this assembled battery 50 ', the tabs of the parallel portion and the portion of the general battery B adjacent in the horizontal direction in the figure are connected in series by the copper bus bar 56, and the general batteries B adjacent in the vertical direction of the drawing are connected in series. The parts to be connected were connected by vibration welding the tabs 11 and 13. The ends of the portion where the general battery B and the bipolar battery A are connected in parallel are connected to the terminals 42 and 44 to constitute positive and negative terminals. 3 except that the detection tabs 12 for detecting the voltage of each layer of the bipolar battery 1 are taken out on both sides of the bipolar battery A and the detection lines (not shown) are taken out to the front part of the assembled battery 50. Since it is the same as that of the assembled battery 50, the same symbol is attached to the same member. Specifically, in order to form the assembled battery 50 ′ shown in FIG. 4, ten general batteries B were sequentially welded in series from the end and connected in series. Furthermore, the bipolar battery A and the general battery B at both ends connected in series are connected in parallel by the bus bar 56 and accommodated in a metal assembled battery case 55. In this way, by connecting any number of bipolar batteries A in series and parallel, an assembled battery 50 ′ that can handle a desired current, voltage, and capacity can be provided. Also in the assembled battery 50 ′, a positive electrode terminal 42 and a negative electrode terminal 44 are formed at the front side of a metal assembled battery case 55. After connecting the batteries A and B in series and parallel, for example, Each positive terminal 42 and negative terminal 44 are connected by a terminal lead 59. In addition, the assembled battery 50 'has a detection tab terminal 54 made of a metal to monitor the battery voltage (the individual cell layers of the bipolar battery B, and the voltage between the terminals of the bipolar battery B and the general battery A). The battery case 55 is installed on the front side surface of the battery case 55 where the positive electrode terminal 42 and the negative electrode terminal 44 are provided. And all the detection tabs 12 of each bipolar battery A (and also general battery B) are connected to the detection tab terminal 54 via the detection line (not shown). In addition, an external elastic body 52 is attached to the lower part of the assembled battery case 55, and when a plurality of assembled batteries 50 ′ are stacked to form a composite assembled battery, the distance between the assembled batteries 50 ′ is maintained. In addition, vibration resistance, impact resistance, insulation, heat dissipation, and the like can be improved.

  In the assembled battery of the present invention, the above-mentioned bipolar battery is further connected in series and parallel to form a first assembled battery unit, and the voltage between the terminals of the first assembled battery unit is the same as that of the other two batteries other than the bipolar battery. There is no particular limitation such as forming a second assembled battery unit in which the secondary batteries are connected in series and parallel, and connecting the first assembled battery unit and the second assembled battery unit in parallel. .

  The other constituent requirements of the assembled battery are not limited at all, and the same constituent requirements as the assembled battery using the existing non-bipolar lithium ion secondary battery can be applied as appropriate. However, since the conventionally known constituent members and manufacturing techniques for assembled batteries can be used, the description thereof is omitted here.

  Next, the above-mentioned assembled battery is a composite assembled battery in which at least two or more assembled batteries are connected in series, in parallel, or in series and in parallel. It is possible to cope with a relatively low cost without manufacturing a battery. That is, the composite assembled battery of the present invention includes at least two or more assembled batteries (including those composed of only the bipolar battery of the present invention and those composed of the bipolar battery of the present invention and other non-bipolar batteries) in series. It is characterized in that it is connected in parallel or in series and parallel, and a standard assembled battery is manufactured and combined to form a composite assembled battery, whereby the specifications of the assembled battery can be tuned. Thereby, since it is not necessary to manufacture many assembled battery types with different specifications, the composite assembled battery cost can be reduced.

As a composite assembled battery, for example, FIG. 5 is a schematic diagram of a composite assembled battery (42V, 6Ah) connected in parallel with an assembled battery (42V, 1Ah) 6 using the bipolar battery shown in FIG. Each assembled battery constituting the composite assembled battery is integrated by a connecting plate and a fixing screw, and an anti-vibration structure is formed by installing an elastic body between the assembled batteries. The tabs of the assembled battery are connected by a plate-like bus bar. That is, as shown in FIG. 5, in order to connect the above-described assembled battery 50 in parallel to form a composite assembled battery 60, the tabs of the assembled batteries 50 provided on the lid of each assembled battery case 55 (see FIG. The positive electrode terminal 42 and the negative electrode terminal 44) are electrically connected using an external positive electrode terminal portion that is a plate-shaped bus bar, an assembled battery positive electrode terminal connecting plate 62 having an external negative electrode terminal portion, and an assembled battery negative electrode terminal connecting plate 64, respectively. To do. Further, a connecting plate 66 having an opening corresponding to the fixing screw hole is fixed to each screw hole (not shown) provided on both side surfaces of each assembled battery case 55 with a fixing screw 67, and each set is assembled. The batteries 50 are connected to each other. Further, the electrode terminal 42 and the negative electrode terminal 44 of each assembled battery 50 are protected by a positive electrode and a negative electrode insulating cover, respectively, and are identified by color-coding them into appropriate colors, for example, red and blue. Further, an anti-vibration structure is formed by installing an external elastic body 52 between the assembled batteries 50, specifically, at the bottom of the assembled battery case 55.

  In this way, a composite assembled battery in which a plurality of assembled batteries are connected in series and parallel can be repaired by simply replacing the failed part even if some of the batteries or the assembled battery fail.

  The vehicle according to the present invention is characterized in that the assembled battery and / or the composite assembled battery is mounted. This makes it possible to meet a large vehicle demand for space by using a light and small battery. By reducing the battery space, the weight of the vehicle can be reduced.

  As shown in FIG. 6, in order to mount the composite battery pack 60 on a vehicle (for example, an electric vehicle or the like), it is mounted under a seat (seat) in the center of the vehicle body of the electric vehicle 70. This is because if it is installed under the seat, the interior space and the trunk room can be widened. The place where the battery is mounted is not limited to under the seat, but may be under the floor of the vehicle, behind the seat back, under the rear trunk room, or in the engine room in front of the vehicle.

  In the present invention, not only the composite battery pack 60 but also the battery pack 50 may be mounted on a vehicle depending on the intended use, or the composite battery pack and the battery pack may be mounted in combination. Good. Further, as the vehicle on which the composite assembled battery or the assembled battery of the present invention can be mounted as a driving power source or an auxiliary power source, the above-described electric vehicle, fuel cell vehicle and hybrid vehicle thereof are preferable, but are not limited thereto. It is not a thing. In addition, as a vehicle on which the assembled battery and / or the composite assembled battery of the present invention can be mounted as, for example, a driving power source or an auxiliary power source, an electric vehicle, a hybrid electric vehicle, a fuel cell vehicle, a hybrid fuel cell vehicle, etc. However, it is not limited to these.

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples.

Example 1
<Formation of electrode>
1. Positive electrode As a positive electrode active material, a spinel LiMn ₂ O ₄ [85% by mass] with an average particle diameter of 2 μm, which is a Li—Mn-based composite oxide, acetylene black [5% by mass] as a conductive additive, and PVDF [10% by mass] as a binder N-methyl-2-pyrrolidone (NMP) as a slurry viscosity adjusting solvent (NMP is volatilized and removed when the electrode is dried, so an appropriate amount was added so as to obtain an appropriate slurry viscosity, not an electrode constituent material. .) Was mixed at the above ratio (showing the ratio converted by the component excluding the slurry viscosity adjusting solvent) to prepare a positive electrode slurry.

  The positive electrode slurry was applied to one side of a SUS foil (thickness 20 μm) as a current collector, placed in a vacuum oven, and dried at 120 ° C. for 10 minutes to form a positive electrode having a dry thickness of 20 μm.

In addition, for the positive electrode of the outermost layer, the positive electrode slurry is applied to one side of a SUS foil (thickness 40 μm) as a positive electrode tab, put in a vacuum oven, dried at 120 ° C. for 10 minutes, and a positive electrode having a dry thickness of 20 μm Formed.

2. Anode Negative electrode active material, non-crystalline carbon material, hard carbon with an average particle size of 4 μm [90% by mass], binder as PVDF [10% by mass], and slurry viscosity adjusting solvent, NMP (appropriate amount to achieve appropriate slurry viscosity) Was added at the above ratio (showing the ratio converted by the component excluding the slurry viscosity adjusting solvent) to prepare a negative electrode slurry.

  The negative electrode slurry was applied to the opposite surface of the SUS foil on which the positive electrode was formed, placed in a vacuum oven, and dried at 120 ° C. for 10 minutes to form a negative electrode having a dry thickness of 20 μm.

  In addition, for the negative electrode of the outermost layer, the negative electrode slurry is applied to one side of a SUS foil (thickness 40 μm) as a negative electrode tab, put in a vacuum oven, dried at 120 ° C. for 10 minutes, and a negative electrode having a dry thickness of 20 μm Formed.

  A bipolar electrode was formed by forming a positive electrode and a negative electrode on both sides of a SUS foil as a current collector. Moreover, the outermost electrode was formed by forming a positive electrode or a negative electrode on one surface of the positive electrode tab and the negative electrode tab.

<Formation of gel electrolyte layer>
A PP nonwoven fabric (porosity: about 50%) having a thickness of about 50 μm was used as a separator.

In the separator, a copolymer of polyethylene oxide and polypropylene oxide (a copolymer having a copolymerization ratio of 5: 1 and a weight average molecular weight of 8000) [5% by mass] as a host polymer and an electrolytic solution EC + DMC (EC: A pregel solution comprising [95% by mass] a lithium salt LiBF ₄ dissolved at 1.0 M in DMC = 1: 3 (volume ratio)) and AIBN [1% by mass with respect to the host polymer] as a polymerization initiator Was immersed and thermally polymerized at 90 ° C. for 1 hour under an inert atmosphere to form a gel electrolyte layer in which the gel electrolyte was held on the nonwoven fabric separator. The thickness of the obtained gel electrolyte layer was about 60 μm.

<Formation of battery stack (battery element)>
As shown in FIG. 1, the bipolar electrode and the outermost electrode, the gel electrolyte layer, and the positive electrode and the negative electrode sandwich the gel electrolyte layer. As shown in FIG. The electrode laminate (battery element) was fabricated by laminating so as to have a laminate structure of 42V bipolar battery. The periphery of the electrode forming portion of the electrode laminate was immersed in an epoxy resin (precursor solution) with a predetermined width, and then the epoxy resin was cured to form an insulating portion.

<Formation and connection of high resistance film on electrode tab>
An aluminum plate having a thickness of 200 μm was used as the positive and negative electrode tabs. An aluminum oxide film (high resistance film) having a thickness of about 0.5 μm was formed on the metal surface of the electrode tab by an anodic oxide film forming method. Specifically, a high-purity aluminum plate was immersed in a 1 M sulfuric acid aqueous solution to form an anode, a large-sized aluminum plate was used as the negative electrode, a DC power source was used, and the output voltage was set to 20 V or higher. In this state, electrolysis was performed for 30 minutes or more to obtain an aluminum oxide film. Only the adhesion part (seal part) was left in the obtained anodic oxide film, and the other part was scraped to reduce the contact resistance.

A positive electrode terminal plate and a negative electrode terminal plate are respectively connected by ultrasonic welding on both outermost current collectors of the battery laminate (battery element) after the insulating portion is formed. The positive electrode lead and the negative electrode lead were joined (electrically connected) to the positive electrode lead and the negative electrode lead, and the positive electrode tab and the negative electrode tab having the high resistance film obtained as described above were further joined (electrically connected) to the positive electrode lead and the negative electrode lead ( (See FIG. 1 (b)).

<Completion of bipolar battery>
Finally, in order to prevent external impact and environmental degradation, the battery laminate as a whole as shown in FIG. 1 is a polymer metal composite laminate film (skin resin layer: nylon and polyester laminate film) having a thickness of 120 μm. , Metal layer: aluminum, metal layer-tab resin layer: polypropylene (PP) three-layer laminate film) is housed in a bag body (battery exterior material), and the outer edge of the battery exterior material is sealed by thermal fusion. By stopping, a bipolar battery in which the positive electrode and the negative electrode tab were taken out of the battery as shown in FIG. 1 was produced.

Example 2
As shown in Table 1 below, the same procedure as in Example 1 was performed except that a tantalum oxide film having a thickness of about 0.5 μm was formed as a high resistance film on the electrode tab instead of the aluminum oxide film. A bipolar battery was produced.

  Specifically, after tantalum is vapor-deposited on the surface of an aluminum plate that is a metal tab, the aluminum plate after tantalum vapor deposition is immersed in a 1M sulfuric acid aqueous solution in the same manner as in Example 1 to form an anode, and an aluminum plate having a large size as a negative electrode The output voltage was set to 20 V or higher using a DC power source. In this state, electrolysis was performed for 30 minutes or more to form a tantalum oxide film.

Example 3
As shown in Table 1 below, the same procedure as in Example 1 was conducted except that a niobium oxide film having a thickness of about 0.5 μm was formed as a high resistance film on the electrode tab instead of the aluminum oxide film. A bipolar battery was produced.

  Specifically, after niobium is vapor-deposited on the surface of an aluminum plate that is a metal tab, the aluminum plate after niobium vapor deposition is immersed in a 1M sulfuric acid aqueous solution in the same manner as in Example 1 to make an anode, and an aluminum plate having a large size as a negative electrode The output voltage was set to 20 V or higher using a DC power source. In this state, electrolysis was performed for 30 minutes or more to form a niobium oxide film.

Example 4
As shown in Table 1 below, the same procedure as in Example 1 was conducted except that a hafnium oxide film having a thickness of about 0.5 μm was formed as a high resistance film on the electrode tab instead of the aluminum oxide film. A bipolar battery was produced.

  Specifically, after hafnium is vapor-deposited on the surface of an aluminum plate that is a metal tab, the aluminum plate after hafnium vapor deposition is immersed in a 1M sulfuric acid aqueous solution in the same manner as in Example 1 to form an anode, and an aluminum plate having a large size as a negative electrode The output voltage was set to 20 V or higher using a DC power source. In this state, electrolysis was performed for 30 minutes or more to form a hafnium oxide film.

Example 5
As shown in Table 1 below, in the same manner as in Example 1 except that a high-resistance film on the electrode tab was replaced with an aluminum oxide film and a zirconium oxide film having a thickness of about 0.5 μm was formed. A bipolar battery was produced.

Specifically, after zirconium was deposited on the surface of an aluminum plate, which is a metal tab, the aluminum plate after zirconium deposition was immersed in a 1M sulfuric acid aqueous solution in the same manner as in Example 1 to form an anode, and an aluminum plate having a large size as a negative electrode , DC power supply, output voltage 2
It was set to 0V or higher. In this state, electrolysis was performed for 30 minutes or more to form a zirconium oxide film.

Example 6
As shown in Table 1 below, in the same manner as in Example 1 except that a zinc oxide film having a thickness of about 0.5 μm was formed as the high resistance film on the electrode tab instead of the aluminum oxide film. A bipolar battery was produced.

  Specifically, after electrolytically plating zinc on the surface of the aluminum plate, which is a metal tab, the aluminum plate after galvanization is immersed in a 1M sulfuric acid aqueous solution in the same manner as in Example 1 to form an anode, and aluminum having a large size as a negative electrode A plate was used, a DC power supply was used, and the output voltage was set to 20 V or higher. In this state, electrolysis was performed for 30 minutes or more to form a zinc oxide film.

Example 7
As shown in Table 1 below, the same procedure as in Example 1 was performed except that a tungsten oxide film having a thickness of about 0.5 μm was formed as a high resistance film on the electrode tab instead of the aluminum oxide film. A bipolar battery was produced.

  Specifically, after vapor-depositing tungsten on the surface of the aluminum plate, which is a metal tab, the aluminum plate after the tungsten vapor deposition is immersed in a 1 M sulfuric acid aqueous solution in the same manner as in Example 1 to form an anode, and an aluminum plate having a large size as a negative electrode The output voltage was set to 20 V or higher using a DC power source. In this state, electrolysis was performed for 30 minutes or more to form a tungsten oxide film.

Example 8
As shown in Table 1 below, in the same manner as in Example 1 except that a high resistance film on the electrode tab was changed to an aluminum oxide film and a bismuth oxide film having a thickness of about 0.5 μm was formed. A bipolar battery was produced.

  In detail, after vapor-depositing bismuth on the surface of an aluminum plate, which is a metal tab, the aluminum plate after bismuth vapor deposition was immersed in a 1 M sulfuric acid aqueous solution in the same manner as in Example 1 to form an anode, and an aluminum plate having a large size as a negative electrode The output voltage was set to 20 V or higher using a DC power source. In this state, electrolysis was performed for 30 minutes or more to form a bismuth oxide film.

Example 9
As shown in Table 1 below, the same procedure as in Example 1 was performed except that an antimony oxide film having a thickness of about 0.5 μm was formed as a high resistance film on the electrode tab instead of the aluminum oxide film. A bipolar battery was produced.

  Specifically, after depositing antimony on the surface of an aluminum plate that is a metal tab, the aluminum plate after the antimony deposition was immersed in a 1 M sulfuric acid aqueous solution in the same manner as in Example 1 to make an anode, and an aluminum plate having a large size as a negative electrode The output voltage was set to 20 V or higher using a DC power source. In this state, electrolysis was performed for 30 minutes or more to form an antimony oxide film.

Example 10
As shown in Table 1 below, as the negative electrode active material, graphite having an average particle diameter of 1 μm, which is a crystalline carbon material, was used instead of hard carbon having an average particle diameter of 4 μm, which is an amorphous carbon material,
As a high resistance film on the electrode tab, a Teflon coating film with a thickness of 10 μm was formed instead of an aluminum oxide film, and a positive / negative structure was changed to a 42V bipolar battery with 10 layers of positive / negative structure (single cell). A bipolar battery was fabricated in the same manner as in Example 1, except that the number of stacked (single cells) was a 420 V bipolar battery with 100 layers.

  Among these, as a method for forming a Teflon (registered trademark) coating film, a method is used in which the powder of the resin to be coated is uniformly adhered to the surface of the tab by electrostatic powder coating and then baked at a high temperature. Manufactured.

  Electrostatic powder coating is a method in which a powder coating is charged by a direct current high voltage obtained by an electrostatic generator, and is attached to a grounded material (object to be coated) by electrostatic attraction. In particular, the Teflon (registered trademark) resin coating of this example was manufactured by baking powder at about 400 ° C. for 1 hour after the powder was coated on the tab with electrostatic powder.

Comparative Example 1
As shown in Table 1 below, a bipolar battery was fabricated in the same manner as in Example 1 except that a high resistance film was not formed on the electrode tab.

(Evaluation of bipolar battery)
In order to evaluate the bipolar battery performance with respect to vibration received from the vehicle when the bipolar battery according to the present invention is mounted on a vehicle using the bipolar batteries obtained in Examples 1 to 10 and Comparative Example 1, A test was conducted.

1. Measurement of peel average value The tab of the battery tab and the battery outer packaging film obtained by the manufacturing method of each example and comparative example 1 were subjected to a tensile test in accordance with JIS K6253, and the tab and film were subjected to a 180 ° tensile test. The peel strength and length at that time were measured. The results of Example 1 and Comparative Example 1 are shown in FIG.

  At this time, the average value of the trapezoidal heel portion of the peel strength was defined as the peel average value, and the strength ratio (%) of the peel average value of each example from the peel average value (reference) of Comparative Example 1 was obtained. The results are shown in Table 1.

2. Insulation test Using an insulation resistance meter, the resistance value between the tab of the battery obtained by the manufacturing method of each example and comparative example 1 and the metal layer in the battery exterior material was measured. The results are shown in Table 1. In Table 1, a sample having an insulation resistance of 100 MΩ or more when 500 V was applied was marked with ◯, and a value less than that was marked with ×.

3. Measurement of specific surface area The specific surface area is a gas adsorption method based on JIS Z8830, and the adsorption amount of a tab having a high resistance film and a tab without a high resistance film obtained by the production method of each example and comparative example 1 (m ² / g) was measured. The results are shown in Table 1. Table 1 shows the ratio (specific surface area ratio) of the amount of adsorption after formation to the amount of adsorption before formation of the high-resistance film (see FIG. 7).

4). Measurement of film resistance value The film resistance value was measured by the measurement method based on JIS K6911 for the dielectric breakdown strength of the tab having the high resistance film obtained by the production method of each example. The results are shown in Table 1.

  Among the examples of the present invention, in the case where a metal oxide film is formed as a high-resistance film on the tab surface, the specific surface area with respect to the base material (the tab without the film) is in the range of 1.1 to 5, specifically 1 It was confirmed that it was in the range of 5-5. From this, high adhesive strength can be expressed by the anchor effect in the tab portion where the sealing performance of the battery is most required due to the minute uneven shape of the film.

  In each example of the present invention, the absolute value of peel strength (tensile strength) is 145 to 230% larger than the case without a film (Comparative Example 1 = reference 100%), and can withstand strong tearing force. I was able to confirm. That is, the absolute value of peel strength (tensile strength) was large compared to the case without a film, and it was confirmed that it could withstand strong tearing force.

  From this, the peel strength (tensile strength) between the resin (battery outer packaging film) and the metal (metal oxide film on the tab surface) against the tearing force input to the tab portion of the battery due to the anchor effect due to the high specific surface area. The absolute value of is large, and it has high adhesive strength and high sealing reliability. On the other hand, the absolute value of the peel strength (tensile strength) is large between the resin (battery outer packaging film) and the resin (resin film on the tab surface) due to the melting and compatibilization of the resins during the thermal fusion treatment of the battery outer packaging material. In addition, it has high adhesive strength and high sealing reliability.

  Moreover, in each Example of this invention, all were excellent in insulation, and it has confirmed that insulation was ensured even if it applied 500V between the metal layer in a tab and a battery exterior material film. Therefore, even if a 500V bipolar battery, which is the upper limit of the working voltage in a vehicle, is produced, sufficient insulation can be ensured between the tab of the battery and the metal layer in the battery outer packaging film, which is suitable for a vehicle power source. I found that it can be used.

Further, in each of the embodiments of the present invention, the film resistance values are all 10 ⁶ V / m or more, specifically 20 × 10 ^{6 to} 1000 × 10 ⁶ V / m, which is a high voltage bipolar battery. Insulation of the tab portion can be ensured. Therefore, insulation can be ensured even when 500 V, which is the upper limit of the working voltage in the vehicle, is applied.

1 is a plan view schematically showing an embodiment of a bipolar battery according to the present invention. It is the sectional view on the AA line of Drawing 1 (a), and is a section schematic diagram showing typically one embodiment of the lamination structure of a bipolar battery. FIG. 2B is a cross-sectional view taken along line B-B in FIG. 1A, in which a laminated structure of a portion where a metal tab of a bipolar battery is sandwiched between heat-sealed portions (seal portions) of a polymer metal composite film of an exterior material It is the cross-sectional schematic which represented typically one Embodiment. In the tensile test according to JIS K6253, the tab of the tab portion of the battery of the bipolar battery of Example 1 and Comparative Example 1 obtained by measurement of the average peel value performed in the examples of the present invention and the battery exterior material film were: It is a graph showing the relationship between peel strength and length (elongation) at the time when a tab and film were subjected to a 180 ° tensile test. It is a schematic diagram which shows an example of the assembled battery which connected the bipolar battery of this invention in 2 series 20 parallel. 3 (a) is a plan view of the assembled battery, FIG. 3 (b) is a front view of the assembled battery, and FIG. 3 (c) is a right side view of the assembled battery. In (c), all show the inside of the assembled battery through the outer case so that it can be seen that the bipolar batteries are connected in series and in parallel. It is a figure which shows an example of the assembled battery which connected the bipolar battery A of this invention, and the general lithium ion secondary battery B10 directly. FIG. 4A is a plan view of the assembled battery, FIG. 4B is a front view of the assembled battery, and FIG. 4C is a right side view of the assembled battery. In (c), all show the inside of the assembled battery through the outer case so that it can be seen that the bipolar battery A and the lithium ion secondary battery B are connected in series and in parallel. It is a figure which shows an example of the composite assembled battery of this invention. FIG. 5A is a plan view of the composite assembled battery, FIG. 5B is a front view of the composite assembled battery, and FIG. 5C is a right side view of the composite assembled battery. It is a schematic diagram which shows the electric vehicle of the state which mounts a composite assembled battery. A cross section schematically showing a state of a high-resistance film, particularly a metal oxide film having a concavo-convex shape formed on the tab surface of the battery of the bipolar battery of the example used in the measurement of the specific surface area performed in the example of the present invention. FIG. Here, specific surface area ratio = surface area of film / projected area = adsorption amount of tab having high resistance film (m ² / g) / adsorption amount of tab without high resistance film (m ² / g).

Explanation of symbols

1 Bipolar battery,
3 Bipolar electrodes,
3a Top layer electrode,
3b, the bottom electrode,
5 electrolyte layer,
7 Insulating layer,
9 electrode laminate,
11 Positive electrode tab,
13 Negative electrode tab,
12 Detection tab,
15 positive lead,
17 Negative lead,
19 Battery exterior material,
19a skin resin layer,
19b metal layer,
19c resin layer between metal layer and tab,
20 seal part,
21 high resistance layer (high resistance film),
42 positive terminal,
44 negative terminal,
50, 50 'battery pack,
52 external elastic body,
53 detection lines,
54 detection tab terminal,
55 battery pack case,
56, 58 Busbar,
59 Terminal lead,
60 composite battery pack,
62 composite battery positive electrode terminal connecting plate,
64 composite battery negative electrode terminal plate,
66 connecting plate,
67 fixing screws,
70 electric car,
A bipolar battery,
B General lithium ion secondary battery.

Claims (7)

In a high-voltage battery having a plurality of combinations of positive electrode layers and negative electrode layers, having a bipolar structure having a polymer metal composite film as a battery exterior material, and capable of outputting a voltage of 400 V or more ,
It has a high resistance layer higher than the metal resistance of the tab metal on the tab surface,
The bipolar battery, wherein the high resistance layer is a metal oxide film having a film thickness of 0.5 μm to 5 μm. In a high-voltage battery having a plurality of combinations of positive electrode layers and negative electrode layers, having a bipolar structure having a polymer metal composite film as a battery exterior material, and capable of outputting a voltage of 400 V or more ,
At least one layer between the tab and the metal layer in the polymer metal composite film has a high resistance layer higher than the metal resistance of the tab metal,
The bipolar battery, wherein the high resistance layer is a metal oxide film having a film thickness of 0.5 μm to 5 μm.   3. The bipolar battery according to claim 1, wherein the high resistance layer is present at least in a resin seal portion on a tab surface. 4.   The bipolar battery according to claim 1, wherein the high resistance layer is a metal oxide film. 5. The bipolar battery according to claim 1, wherein the high resistance layer has a resistance value of 10 ⁶ V / m or more.   The bipolar battery according to any one of claims 1 to 5, wherein a range of a specific surface area of the high resistance layer is 1.1 to 5.   The bipolar battery according to claim 1, wherein the high resistance layer is an aluminum oxide film.

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