JP4984386B2 - Battery structure - Google Patents

Description

  The present invention relates to a bipolar battery, an assembled battery, a composite assembled battery, and a vehicle equipped with the assembled battery or the composite assembled 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 Patent Documents 1 and 2).

  Such a bipolar battery has a structure in which, for example, a positive electrode active material layer is disposed 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. A sheet-type bipolar battery having a material layer, 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, and a bipolar electrode The first set having one unit or two or more units connected in series and the second set having the same number of bipolar electrode units as the first set 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 included in the first set and the bipolar electrode unit in the second set that is mirror-imaged with each other are connected directly in parallel by the lead wires. There are bipolar battery of the sheet form characterized by comprising a connection (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.
Japanese Patent Laid-Open No. 2000-1000047 JP 2000-195495 A

  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 done.

  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. Therefore, the use of a voltage exceeding 400 V has been studied. However, a sheet-type bipolar battery has a configuration in which the power generation 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. And a metal tab (electrode terminal lead) that is electrically connected to both end electrodes of the power generation 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.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a bipolar battery, an assembled battery, a composite assembled battery, and an assembled battery capable of ensuring insulation even when a high voltage is applied. It is providing the vehicle carrying a composite assembled battery. More specifically, a bipolar battery, an assembled battery, a composite assembled battery, and a vehicle equipped with the assembled battery or the composite assembled battery that can ensure insulation between the tab and the metal layer in the exterior film even when a high voltage is applied. Is to provide.

The present invention includes a power generation element having a plurality of combinations of positive electrode layers and negative electrode layers, a polymer metal composite film as an exterior material covering the power generation element, and the polymer metal composite film taken out from the inside to the outside. A tab, and the tab includes a hole-shaped portion having a linear shape across the bonding region, and the longitudinal direction of the hole-shaped portion is a bipolar battery. This is achieved by a bipolar battery that is inclined at a predetermined angle with respect to the longitudinal direction .

  According to the present invention, in the adhesion region between the tab and the polymer metal composite film, the tab has a portion where the cross-sectional shapes of the tab are different from each other, so that an uneven shape portion or a hole shape portion is formed in the adhesion region of the tab. obtain. Thereby, the area of the shortest part between the tab and the metal layer of the polymer metal composite film can be reduced, and the possibility of dielectric breakdown is reduced. Therefore, it is possible to ensure insulation between the bipolar terminals even when a high voltage is applied. 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 addition, the formation of concave and convex portions or hole-shaped portions provides an increased contact area or exerts an anchor effect at the joint between the tab and the resin where the battery seal is most required. This can improve the reliability of battery sealing.

  A bipolar battery according to the present invention includes a power generation element having a plurality of combinations of a positive electrode layer and a negative electrode layer, a polymer metal composite film as an exterior material covering the power generation element, and from the inside of the polymer metal composite film to the outside. The bipolar battery is characterized in that the tab has a tab to be taken out, and the tab has a portion in which the cross-sectional shapes of the tab are different from each other in an adhesive region between the tab and the polymer metal composite film. 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 it is distinguished by the type of electrolyte of the bipolar battery, it should not be particularly limited, and a liquid electrolyte type battery in which an electrolytic solution is impregnated in a separator (including a nonwoven fabric separator) or a polymer battery is also referred to. 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 this.

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

  FIG. 1 is a plan view schematically showing one embodiment of a bipolar battery according to the present invention. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1, and is a schematic cross-sectional view schematically showing an embodiment of a laminated structure of a bipolar battery. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1, in which the metal tab of the bipolar battery is laminated between the heat-sealed portions (seal portions) of the polymer metal composite film of the exterior material. 1 is a schematic cross-sectional view schematically showing an embodiment of a structure.

  The bipolar battery 1 of the present invention includes a power generation element 9 having a plurality of combinations of positive electrode layers and negative electrode layers, a battery exterior material 19 that covers the power generation element 9, and a tab 11 that is taken out from the inside of the battery exterior material 19. , 13.

  Here, the bipolar battery 1 has a so-called bipolar structure in which a plurality of series configurations of combinations of a positive electrode layer and a negative electrode layer exist. In the bipolar structure, 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) is provided on the other side. It is assumed that the electrolyte layer 5 is sandwiched between the provided bipolar electrodes 3 and the positive and negative electrodes of the adjacent bipolar electrodes 3 are opposed to each other. That is, in the bipolar battery 1, a power generation element 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. (Also referred to as electrode laminate, battery element or bipolar battery body) 9.

  In the present invention, the uppermost electrode 3a and the lowermost electrode 3b, which are the outermost parts of the power generation element 9 in which a plurality of the bipolar electrodes 3 are stacked, may not be bipolar electrodes. For example, 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 uppermost 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. 2, the positive and negative electrode tabs 11 and 13 taken out of the battery and the current collector (or electrode terminal plate) of the outermost electrodes 3a and 3b are electrically connected to each other. The 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, respectively. However, 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 be a positive electrode and a negative electrode lead. The positive and negative tabs 11 and 13 are connected to vehicle loads (motors, electrical components, etc.) not shown, and very large charge / discharge currents flow through these tabs 11 and 13. Therefore, the width and thickness (in other words, the cross-sectional area) of the positive electrode tab 11 and the negative electrode tab 13 are mainly determined by the current value at the time of charging / discharging that will flow through it. In addition, the power generation element 9 is sealed in the battery exterior member 19 under reduced pressure in order to prevent external impact and environmental degradation during use.

  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, by joining a part or all of the peripheral part of the battery outer packaging material 19 by heat fusion or the like, the power generation element 9 is sealed (sealed) in the battery outer packaging material 19, and the positive and negative electrode tabs 11 and 13 are sealed. Is configured to be taken out of the battery exterior member 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 unit cell is set to 4.2 V, the voltage between the terminals of the power generation element 9 (battery) having a configuration in which unit cell layers for several tens to hundreds of cells are connected in series. (Voltage) may be 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, in the bonding region A ₁ between the tabs 11, 13 and the battery outer package 19, tab 11, 13 cross-sectional shape of the tab is provided with a different site on each other. That is, an uneven shape portion (including a fine uneven shape) or a hole shape portion can be formed in the adhesion region of the tabs 11 and 13. In FIG. 3, the hole shape portion and the uneven shape portion are not shown. Here, the cross-sectional shapes of the tabs 11 and 13 can be changed in one or both of the longitudinal direction and the lateral direction of the tabs 11 and 13.

Thereby, the area of the shortest part between the tabs 11 and 13 and the metal layer 19b of the battery exterior member 19 can be reduced, and the possibility of dielectric breakdown can be reduced. That is, the greater the area of the portion where the distance between the metal layer 19b and the tabs 11 and 13 is the smallest, the greater the probability that the insulation will break. Here, tabs 11, 13 and there is a high possibility that dielectric breakdown occurs since both are closest in the adhesion area A ₁ of the battery exterior material 19, have a change in the cross-sectional shape of the tabs 11 and 13 in the bonding region A ₁ As a result, insulation as a whole can be ensured. Therefore, it is possible to ensure insulation between the bipolar terminals even when a high voltage is applied. 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. It should be noted that a battery used for general consumer use (for example, a battery for a mobile phone or a personal computer is about several V to 20 V, which has a high possibility of causing no problem even if an electric shock is caused by leakage during carrying). The invention specification may be overspec.

  In addition, the formation of the concavo-convex shape portion or the hole shape portion increases the contact area (the concavo-convex shape portion) or the anchor effect (the concavo-convex shape portion, Therefore, high adhesive strength can be expressed, and the battery sealing reliability is improved.

In this embodiment, the metal layer 19b of the battery exterior material 19 in the bonding area A ₁ are substantially flat, in the bonding region A _1, tabs 11 and 13 on the insulating distance between the tab and the metal layer 19b mutual It has different parts. That is, to have a change in the cross-sectional shape of the tabs 11 and 13, the metal layer 19b in the bonding area A ₁ by a substantially planar, and is it possible to ensure a reliably insulation distance.

  Further, in the present embodiment, at least one or more polymer adhesive layers 21 are provided around the tabs in the adhesion region between the tabs 11 and 13 and the battery exterior material 19. In this way, by additionally setting the polymer adhesive layer 21 between the tabs 11 and 13 and the battery exterior material 19, the insulation distance between the tabs 11 and 13 and the metal layer 19 b is set to the thickness of the polymer adhesive layer 21. Can only be expanded further. Therefore, the insulation between the tabs 11 and 13 and the metal layer 19b can be more easily secured, and the adhesive strength can be improved due to the adhesive resin used for the polymer adhesive layer 21. Moreover, since the burr | flash which may arise in the tabs 11 and 13 etc. can be received with the adhesive resin of the polymer adhesion layer 21, it becomes possible to raise the intensity | strength with respect to a burr | flash. As the polymer adhesive layer 21, a resin such as polypropylene (PP), polyethylene terephthalate (PET), or modified PP can be suitably used. However, in the present invention, the formation of the polymer adhesive layer 21 can be omitted.

  FIG. 4 is a diagram for explaining an example of a tab in a bipolar battery.

In the example of FIG. 4, the tab 11 and 13, it has a hole-shaped portion 31 in the bonding area _{A 1.} Incidentally, reference numerals in FIG. "A _2" indicates a region where the polymer adhesive layer 21 is formed. By providing the hole-shaped portion 31 in the tabs 11 and 13, the area of the shortest portion between the tabs 11 and 13 and the metal layer 19 b is reduced by the area of the hole-shaped portion 31. This is effective in reducing the possibility of destruction. The opening shape of the hole-shaped portion 31 is not particularly limited, and is rectangular (see FIGS. 4, 9, 16 and 17), parallelogram (see FIGS. 5 and 10), and substantially square (see FIGS. 12 to 12). The object of the invention can be achieved by a shape such as a circle in addition to FIG. Further, the size, opening area, and number of the hole-shaped portions 31 are not particularly limited.

  Here, the projected area of a tab having a hole-shaped portion or a concavo-convex shape portion in the adhesion region (excluding the hole-shaped portion or the concave-shaped portion) is assumed to be the projected area of the tab when there is no hole-shaped portion or concavo-convex shape portion. The value divided by the projected area ratio is 100% or less, preferably 35 to 45%.

  In addition, a hole shape is preferable for the anchor effect, but an uneven shape is preferable in order to secure an area in the current flow direction and reduce resistance.

  The hole-shaped portion 31 may be processed integrally with the outer periphery of the tabs 11 and 13, or may be processed separately after the outer peripheral processing. Here, if there are burrs in the periphery of the tab, the insulation distance at the tip of the burrs will be shortened, so it is necessary to suppress the generation of burrs as much as possible. It is also desirable to perform a pressing process and a cutting process for removing burrs after the processing of the hole-shaped portion 31 in order to further secure insulation.

Further, in the bonding region A _1, a pair of outer edges 32 and 33 located on both sides in the width direction of the tabs 11 and 13, preferably form a single straight line, respectively. In other words, the outer edge 32 and 33, within the bonding area _{A 1,} its (tangential) angle does not change. For example, the edge portion 34 as shown in Figure 4, it is desirable not contained within the bonding areas A _1. This is the outer edge of the tab in the bonding area A ₁ do not form a straight line, when the inside at an angle of bonded area A ₁ is changed, the tab of the machining, the possibility of the tab is bent Because there is. In this case, the insulation distance of the bent tips in the tabs 11 and 13 becomes smaller than other portions, and dielectric breakdown is likely to occur.

Since it no edge portion 34 in the bonding area _{A 1,} in the case of the structure of the tabs 11 and 13 shown in Figure 4, bonding region _A tab 11 and 13 within the range of ₁ and the battery outer package 19 It is sufficient that the bonding is performed. This is because the possibility that the tab is curved at the straight portion is low, and the insulation distance is easily maintained. Incidentally, even the tab as shown in Figure 5 to be described later, the angle changes internally (except for the boundary) of the adhesive area A ₁ does not occur, within the scope of the present invention.

  FIG. 5 is a diagram showing another example of a tab in a bipolar battery. In addition, the part which is common in the already demonstrated part attaches | subjects the same code | symbol, and abbreviate | omits description (it is the same also in FIGS. 7-17).

  In the example of FIG. 5, the tabs 11a and 13a are inclined at a predetermined angle α with respect to the longitudinal direction of the bipolar battery (the same as the tab take-out direction in FIG. 5). . The adhesion between the tabs 11a and 13a and the resin is particularly required to withstand the internal pressure of the cell. However, since the adhesive strength between the tabs 11a and 13a and the resin is increased by having such a predetermined angle α, it is effective. . Here, by making the hole-shaped portion 31a oblique, strong adhesive strength between the resin and the resin can be obtained not only in the longitudinal direction of the bipolar battery but also in a direction orthogonal thereto. Therefore, the adhesive strength of the tabs 11a and 13a as a whole is improved.

  FIG. 6 shows the result of a tensile test in which the adhesive strength of the tab portion was measured. In FIG. 6, the graph of the structure of the present invention (described later in Example 1) shows the peel strength (tensile strength) of the structure using the tabs 11 and 13 having the hole-shaped portions 31 shown in FIG. The graph of Example 3) shows the peel strength of the structure using the tabs 11a and 13a having the obliquely inclined hole shape portion 31a shown in FIG. 5, and the graph of the conventional structure (Comparative Example 1 described later) shows the hole shape portion. The peel strength of the structure using the conventional tab which does not have is shown. Here, the tensile test was based on JIS K6253, the 180 degree tensile test was done with respect to the tab and the polymeric metal composite film (battery exterior material), and the peel strength and length at that time were measured.

  From this result, it can be confirmed that the structure of the present invention has a larger absolute value of peel strength (tensile strength) than the conventional structure and can withstand strong tearing force. Furthermore, the structure having the obliquely inclined hole shape portion 31a shown in FIG. 5 (Example 3) has a higher peel strength than the structure having the hole shape portion 31 shown in FIG. 4 (Example 1). It can be confirmed that it is large.

FIG. 7 is a view for explaining still another example of the tab in the bipolar battery, and FIG. 8 is an enlarged cross-sectional view in the vicinity of an adhesion region between the tab and the battery exterior material in FIG. In the example of FIGS. 7 and 8, the tab 11b, 13b has a concave portion 35 in the bonding area _{A 1.} The portion other than the concave portion 35 in the bonding area A ₁ and the concave portion 35 forms a result, the concave-convex part.

Tab 11b, by providing the concave portion 35 to 13b, the tab 11b, the area of the shortest distance portion (portion having the insulating distance _{D 1} shown in FIG. 8) between the 13b and the metal layer 19b, those depressions Since the area is reduced by the area of the shape portion 35, it is effective in reducing the possibility of dielectric breakdown. The average of the insulation distance (average of the portion having a portion with the insulating distance D ₂ having an insulation distance D ₁ shown in FIG. 8) is greater than the insulation distance D ₁ of the conventional tabs having no concave portion 35 Become. The opening shape of the concave portion 35 is not particularly limited. Further, the size (including the depth), the opening area, and the number of the concave portions 35 are not particularly limited.

  Here, the projected area of a tab having a hole-shaped portion or a concavo-convex shape portion in the adhesion region (excluding the hole-shaped portion or the concave-shaped portion) is assumed to be the projected area of the tab when there is no hole-shaped portion or concavo-convex shape portion. The value divided by the projected area ratio is 100% or less, preferably 35 to 45%.

  9-11 is a figure which shows the further another example of the tab in a bipolar battery. The tabs 11c and 13c shown in FIG. 9 are different from the tabs 11 and 13 shown in FIG. 4 in that they do not have an edge portion 34 (in other words, a notch shape), and are the same in other points. The tabs 11d and 13d shown in FIG. 10 are also different from the tabs 11a and 13a shown in FIG. 5 in that they do not have the edge portion 34, and are the same in other points. The tabs 11e and 13e shown in FIG. 11 are also different from the tabs 11b and 13b shown in FIGS. 7 and 8 in that they do not have the edge portion 34, and are the same in other points.

FIG. 12 is a diagram showing still another example of a tab in a bipolar battery. In the example of FIG. 12, hole shape portion 31b of the tab 11f, 13f is an adhesive in region _{A 1,} at least two in the extraction direction of the tab is formed separately in (in FIG. 12 3).

  Therefore, even when it is considered that the sealing performance is weakened by the electrolytic solution from the inside of the battery, the metal-resin portion having a relatively weak adhesive strength is separated from the resin-resin adhesive portion. This will improve the prevention of leakage. For example, if there is a pinhole penetrating from the inside to the outside of the battery, it is likely to cause a liquid leak. In this way, the formation of the penetrating pinhole is prevented by separating the metal-resin adhesion portion. Will be able to.

  FIG. 13 is a diagram showing still another example of a tab in a bipolar battery. The tabs 11g and 13g illustrated in FIG. 13 are different from the tabs 11f and 13f illustrated in FIG. 12 in that the edge portion 34 is not provided, and are the same in other points.

FIG. 14 is a diagram showing still another example of a tab in a bipolar battery. In the example of FIG. 14, the tab 11h, hole shape portion 31c of 13h is an adhesive in region _{A 1,} are formed to be separated into at least two in the extraction direction of the tab (FIG. 14 3). Furthermore, the positions of the separated hole-shaped portions 31c in the direction (W direction) perpendicular to the tab take-out direction are shifted from each other at least partially. For example, in FIG. 14, the position of the hole-shaped portion 31 c in the middle row R ₂ among the _three rows R _{1 to} R ₃ formed by arranging a plurality of hole-shaped portions 31 c in the W direction is the other row R. ₁ and R ₃ are displaced from the position of the hole-shaped portion 31 c in the W direction. That is, the plurality of hole-shaped portions 31c separated in the tab take-out direction are not arranged in a straight line in the tab take-out direction (L direction). By such a shift of the position of the hole-shaped portion 31c in the W direction, it is possible to further prevent the formation of a penetrating pin hole, which is more effective in preventing liquid leakage.

  FIG. 15 is a diagram showing still another example of a tab in a bipolar battery. The tabs 11i and 13i shown in FIG. 15 are different from the tabs 11h and 13h shown in FIG. 14 in that they do not have the edge portion 34, and are the same in other points.

FIG. 16 is a diagram showing still another example of a tab in a bipolar battery. Examples of the tab 11j of Figure 16, in 13j, tabs 11jb in the bonding area _{A 1,} the cross-sectional area of 13jb, the tabs 11ja in outer bonding area _{A 1,} 13Ja, and 11Jc, the cross-sectional area of 13jc and (minimum sectional area) It is said that it is equal or better. In other words, the bonding area _{A 1} of the tab 11jb by the formation of hole-shaped portion 31, such that the resistance of 13jb does not drop, the projected area of the tab is increased. Thereby, the improvement of adhesiveness and the maintenance of a tab resistance value can be ensured. According to the structure of FIG. 16, the resistance value can be maintained without increasing the thickness of the tab. In the structure other than the structure of FIG. 16 (and FIG. 17 to be described later), the projected area of the tab is reduced by forming the hole-shaped portion. Therefore, in order to maintain the resistance value of the tab, the projected area is increased. Only the tab thickness needs to be increased. However, if it is not desired to increase the thickness of the tab, the width of the tab including the hole-shaped portion may be determined and secured in advance so that the heat generation of the tab can be allowed even at the maximum current value to be used.

Tab 11jb bonding areas _{A 1,} 13Jb and bonding areas _{A 1} outside the tab 11ja, 13Ja, and 11Jc, bonding between 13jc is desirably carried out by vibration welding. This is because vibration welding lowers the contact resistance and prevents an unexpected chemical reaction since a different material is not used for bonding.

  FIG. 17 is a diagram showing still another example of a tab in a bipolar battery. The tabs 11k and 13k shown in FIG. 17 are different from the tabs 11j and 13j shown in FIG. 14 in that they do not have the edge portion 34, and are the same in other points.

  As mentioned above, although it demonstrated centering on the main structural requirements of the bipolar battery concerning this invention, it does not specifically limit regarding the other component of the bipolar battery of this invention, It comprises suitably using a conventionally well-known thing Is something that can be done. Hereinafter, the bipolar lithium ion secondary battery will be described as an example, and its constituent elements will be described. However, it goes without saying that the present invention should not be limited to this.

[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 cladding material, copper-aluminum cladding material, SUS-aluminum cladding 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. 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. 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 aid for increasing the viscosity, and it is not necessary to include a host polymer, an electrolytic solution, or a lithium salt as a raw material of 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 , Li—Cr such as Li ₂ Cr ₂ O ₇ and Li ₂ CrO _4. Li-Ni composite oxides such as LiNiO ₂ , Li-Fe composite oxides such as Li _x FeO _y and LiFeO _2, and Li-V composite oxides such as Li _x V _y O _z And selected from Li metal oxides such as those obtained by substituting a part 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 sulfate compounds such as LiFePO ₄ ; transition metal oxides and sulfides such as V ₂ O ₅ , MnO ₂ , TiS ₂ , MoS ₂ , and MoO ₃ ; PbO ₂ , AgO, NiOOH etc. are mentioned.

  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 a 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 particularly unstable overcharge and overdischarge states of the battery can be detected and dealt with. Can be improved. 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, the voltage of each single cell layer and the entire bipolar battery can be easily detected.

  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. In this case, the same electrolyte solution is held in a polymer skeleton that does not have any. 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 kind selected from organic acid anion salts such as Li (C ₂ F ₅ SO ₂ ) ₂ N (lithium bis (perfluoroethylenesulfonylimide); also referred to as LiBETI) Cyclic carbonates such as propylene carbonate and ethylene carbonate; lithium carbonate (electrolyte salt); chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, Ethers such as 1,2-dimethoxyethane and 1,2-dibutoxyethane; lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; A material using a plasticizer (organic solvent) such as an aprotic solvent in which at least one selected from methyl formate or a mixture of two or more thereof 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 therefore 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. Should. 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 included. 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, and Li _0.17 C (LiC ₆ ). It is done. 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 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 inclined 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 particularly unstable overcharge and overdischarge states of the battery can be detected and dealt with. Can be improved. 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. Should. 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) and the electrolytic solution is wide. When 100% by mass of the polymer is an all solid polymer electrolyte and 100% by mass of the electrolytic solution is a liquid electrolyte, an intermediate thereof Are all gel electrolytes.

  The host polymer of the gel electrolyte is not particularly limited, and conventionally known ones 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 , 1,2-dibutoxyethane, etc. Lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; at least one or more selected from methyl acetate and methyl formate A mixed organic solvent (plasticizer) such as an aprotic solvent 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 ion conductivity and the like. 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. A polyalkylene oxide polymer such as PEO and PPO can dissolve lithium salts such as LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) ₂ well. Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure.

(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. It has the 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). The average diameter of the micropores in the separator is within the above range, so that 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, in addition to improving the heat resistance (safety) of the battery, it is possible to prevent the gas from coming out and the heat fusion part (seal part) of the battery exterior material from opening. 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%. Since the porosity of the separator is in the above range, the output is reduced for the reason of preventing the output from decreasing due to the resistance of the electrolyte (electrolyte solution) and the short circuit due to the fine particles penetrating through the pores (micropores) of the separator. This has the effect of ensuring both reliability. 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 to hold the electrolyte is not particularly limited, and can be produced 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 under the temperature during production and use, and is stable without any reactivity or solubility with respect to the gel electrolyte. In addition, conventionally known ones can be used. 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.

  The electrolyte layers (a) to (c) may be used 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. In other words, 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 via the electrode lead. A terminal board may not be used (see FIG. 2).

  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.

[Positive electrode and negative electrode tab (tab or electrode tab)]
As shown in FIG. 2, the positive and negative electrode tabs 11 and 13 used in the present invention have positive and negative electrode leads 15 connected to a current collector (or an electrode terminal plate connected to the outermost electrode), 17 may be connected to a positive / negative electrode terminal plate or positive / negative electrode lead connected to a current collector of the outermost layer electrode (not shown), or may be connected to an outermost layer electrode. There is no particular limitation such that a part of the current collector may be formed to be extended (not shown). In addition, the part taken out from the battery exterior material 19 to the outside of the battery does not affect the product (for example, automobile parts, particularly electronic devices) by contacting with peripheral devices or wiring and causing leakage. You may coat | cover with the heat-shrinkable 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.

  The metal resistance of the tab is usually about 1 to 50 Ω · m, depending on the type of the tab metal, and is about 10 −7 to 10 −6 V / m for convenience in terms of V / m. It is.

  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, the tab can be taken out of the battery from the opposite sides, or the positive tab and the negative tab can be taken out from the same side. The positive electrode tab and the negative electrode tab may be separately taken out from adjacent sides, but there is no particular limitation, but in order to form a battery pack by connecting a plurality of these batteries, FIG. 19 is convenient from the viewpoint of wiring and the like, and it is preferable to take out the positive electrode tab and the negative electrode tab separately from opposite sides as shown in FIG. .

[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 bypasses the overcharged or overdischarged cell to perform charging / discharging. 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, there is no need to form a hole-shaped portion or a concavo-convex shape portion like the electrode tab of the present invention.

  The same material as 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 particularly 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.

  The resin layer 19c between the metal layer and the tab includes internal insulation, heat-fusibility, chemical resistance (resistance to electrolytes, 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) or a polypropylene film (heat fusion insulating film) 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. 2, when two polymer metal composite films on the upper and lower sides are used by heat-sealing, the same material may be used for each layer in the two polymer metal composite films. A different material may be used.

In the present invention, a polymer metal composite film is used, and a seal part is formed by joining a part or all of the peripheral part thereof by heat fusion, and the power generation element 9 is housed and sealed. In this case, in a state bonded area A ₁ corresponds to a part of the seal portion (heat-sealed portion), which ensures the insulation between the positive electrode and the negative electrode tabs 11, 13 and the battery outer package 19, the positive electrode and the negative electrode tab 11 , 13 may have a structure in which the leading-out portion of the battery 13 is exposed to the outside of the battery exterior member 19. 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, or 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, the manufacturing method of the bipolar battery of the present invention is not particularly limited except for the addition of the hole-shaped portion or the concavo-convex shape portion to the tab described above, and various conventionally known methods are appropriately used. Can be 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 benzyldimethyl ketal, and examples of the thermal polymerization initiator include azobisisobutyronitrile, t-hexylperoxypiparate, and the like, but are not limited thereto. 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 electrodes formed with a cut-out are cut into a suitable size, and the cut-out electrodes are directly bonded together to produce a bipolar battery body (power generation element).

    (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 (power generation element).

The number of stacked power generation elements 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 power generation element is immersed or injected or impregnated with epoxy resin (precursor solution) or the like with a predetermined width. 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) (see FIG. 2). 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. 18 shows a schematic diagram of an assembled battery (42V1Ah) in which the bipolar batteries (24V, 50 mAh) of the present invention are 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. 18, five bipolar batteries 1 are connected in parallel by a bus bar 56, and five bipolar batteries 1 connected in parallel are connected to each other with 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 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. 19 shows an assembled battery in which bipolar battery A (42 V, 50 mAh) and 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. 18 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 code | symbol was attached | subjected to the same member. Specifically, in order to form the assembled battery 50 ′ shown in FIG. 19, ten general batteries B were connected in series by sequentially welding the bus bar 56 and vibrations from the end. 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 those of 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. 20 is a schematic diagram of a composite assembled battery (42V, 6Ah) in which assembled batteries (42V, 1Ah) using the bipolar battery shown in FIG. 18 are connected in parallel. 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. 20, in order to connect the six assembled batteries 50 in parallel to form the composite assembled battery 60, the tabs of the assembled batteries 50 provided on the lid of each assembled battery case 55 ( 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. 21, 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) at 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. In addition, 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 effect of this invention is demonstrated using a following example , a reference example, and a comparative example. However, the technical scope of the present invention is not limited to the following examples.

FIG. 22 shows the configurations and evaluation results of bipolar batteries of Examples , Reference Examples, and Comparative Examples.

<Production method of bipolar battery>
Taking the reference example 1 as an example, a method for manufacturing a bipolar battery will be described. Other Examples, Reference Examples, and Comparative Examples were manufactured in substantially the same manner as Reference Example 1 except that the tabs having the specifications described in FIG. 22 were used.

  First, 15 μm of a Li—Mn-based positive electrode material (average particle size: 5 μm) is applied to SUS 15 μm as a reference foil, and then an amorphous carbon material hard carbon negative electrode material (average particle size) is formed on the opposite surface of the positive electrode 6 μm product) was applied at 15 μm.

  The precursor of the cross-linked gel electrolyte was impregnated into a polyester nonwoven fabric separator (25 μm thickness: hardness JISA 60) and overlaid on the electrode material.

  For the electrodes on both sides, only the same positive electrode material or negative electrode material was applied to one surface of the same foil.

  These electrodes were stacked (one on each side + 8 layers in the center) to form a 10-layer bipolar battery.

  An Al tab (200 μm thickness: width 55 mm) was vibration welded on the positive electrode end side of this bipolar electrode, and a Cu tab (200 μm thickness: width 55 mm) was vibration welded on the negative electrode end side. Thus, the entire bipolar electrode integrated with the tab was sealed with a battery exterior material (laminate) (see FIG. 1 for an external view).

Here, the opening shape of the hole shape portion of the tab was 5 mm × 10 mm, four hole shape portions were formed in a tab width of 55 mm, and cutout shapes having a length of 5 mm were provided on both sides (see FIG. 4). Laminated material was adhered only to the portion of the bonding region A ₁ shown in FIG.

  This bipolar battery was heat-crosslinked at about 80 ° C. for about 2 hours to produce a 10-layer bipolar battery.

<Configuration of Examples , Reference Examples and Comparative Examples>
In Reference Example 1, the number of structural units forming a layer (number of stacked layers) is 10, the tab is the structure shown in FIG. A bipolar battery in which the negative electrode active material is an amorphous carbon material was used.

In Reference Example 2, a bipolar battery having the same configuration as in Reference Example 1 was used except that the tab had the structure shown in FIG.

In Example 1 , a bipolar battery having the same configuration as that of Reference Example 1 was used except that the tab had the structure shown in FIG.

In Example 2 , a bipolar battery having the same configuration as that of Reference Example 1 was used except that the tab had the structure shown in FIG.

In Reference Example 3 , a bipolar battery having the same configuration as that of Reference Example 1 was used except that the tab had the structure of FIG. 7 and did not have a polymer adhesive layer.

In Reference Example 4 , a bipolar battery having the same configuration as in Reference Example 3 was used except that the tab had the structure shown in FIG.

In Reference Example 5 , a bipolar battery having the same configuration as that of Reference Example 1 was used except that the tab was the structure shown in FIG. 12 and the positive electrode active material was a Li—Ni based composite oxide.

In Reference Example 6 , a bipolar battery having the same configuration as that of Reference Example 5 was used except that the tab had the structure shown in FIG.

In Reference Example 7 , a bipolar battery having the same configuration as that of Reference Example 5 was used except that the tab had the structure shown in FIG.

In Reference Example 8 , a bipolar battery having the same configuration as that of Reference Example 5 was used except that the tab had the structure shown in FIG.

In Reference Example 9 , a bipolar battery having the same structure as in Reference Example 1 was used except that the tab had the structure shown in FIG. 16 and did not have a polymer adhesive layer, and the negative electrode active material was a crystalline carbon material.

In Reference Example 10 , a bipolar battery having the same configuration as that of Reference Example 9 was used except that the tab had the structure shown in FIG.

In Reference Example 11 , a bipolar battery having the same configuration as in Reference Example 2 was used except that the number of layers was 100.

In Comparative Example 1, a bipolar battery having the same configuration as Reference Example 1 was used except that the tab was a flat plate and did not have a polymer adhesive layer.

  In FIG. 22, the contact area ratio is the contact area between the tab having a hole-shaped portion or a concavo-convex shape portion and a resin in the bonding region, and assuming that the hole-shaped portion or the concavo-convex shape portion does not exist. Indicates the value divided by. The projected area ratio is the projected area of a tab having a hole-shaped portion or a concavo-convex shape portion (viewed from above) in the bonding region, assuming that there is no hole-shaped portion or concavo-convex shape portion. Indicates the divided value.

<Test method>
1. Measurement of Peel Average Values For the batteries of each Example , Reference Example and Comparative Example 1, a 180 ° tensile test was performed on the tab and the battery outer packaging film according to a tensile test based on JIS K6253. Peel strength and length were measured. The results of Reference Example 1, 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 and Reference Example to the peel average value (reference) of Comparative Example 1 was obtained. The results are shown in FIG.

2. Insulation test Using an insulation resistance meter, the resistance value between the tab and the metal layer of the battery exterior material was measured for the batteries of each of the examples , reference examples, and comparative example 1. The results are shown in FIG. In FIG. 22, a sample having an insulation resistance of 100 MΩ or more when 500 V is applied is indicated by ◯, and a case where the insulation resistance is less than that is indicated by ×.

3. Inspection of leakage characteristics Regarding the batteries of each Example , Reference Example and Comparative Example 1, when the storage was performed at 60 ° C. for 30 days, “X” indicates that leakage occurred from the tab portion, and “No” indicates that there was no leakage. did. Liquid leakage was determined by visual observation and solution odor.

<Evaluation results>
In each of the examples and reference examples of the present invention, it was confirmed that insulation was ensured even when 500 V was applied between the tab and the metal layer in the battery exterior material film, all having excellent insulating properties. 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 examples and reference examples of the present invention, the peel strength (tensile strength) is 130 to 250% as compared with the case where the tab is a flat plate without a hole-shaped portion or a concavo-convex shape portion (Comparative Example 1 = reference 100%). It was confirmed that the absolute value of (strength) was large and could withstand a strong tearing force.

  From this, it can be seen that the addition of the hole-shaped portion or the concavo-convex shape portion to the tab increases the contact area between the tab and the resin or exerts the anchor effect. Therefore, the absolute value of the peel strength (tensile strength) is large with respect to the tearing force input to the tab portion of the battery, and a high adhesive force can be maintained.

In addition, it was confirmed that each of the examples and reference examples of the present invention had high seal reliability without occurrence of liquid leakage.

1 is a plan view schematically showing an embodiment of a bipolar battery according to the present invention. It is sectional drawing which follows the II-II line | wire of FIG. It is sectional drawing which follows the III-III line of FIG. It is a figure for demonstrating an example of the tab in a bipolar battery. It is a figure which shows the other example of the tab in a bipolar battery. It is a figure which shows the result of the tension test which measured the adhesive strength of the part of a tab. It is a figure for demonstrating the further another example of the tab in a bipolar battery. FIG. 8 is an enlarged cross-sectional view in the vicinity of an adhesion region between a tab and a battery exterior material in FIG. 7. It is a figure which shows the further another example of the tab in a bipolar battery. It is a figure which shows the further another example of the tab in a bipolar battery. It is a figure which shows the further another example of the tab in a bipolar battery. It is a figure which shows the further another example of the tab in a bipolar battery. It is a figure which shows the further another example of the tab in a bipolar battery. It is a figure which shows the further another example of the tab in a bipolar battery. It is a figure which shows the further another example of the tab in a bipolar battery. It is a figure which shows the further another example of the tab in a bipolar battery. It is a figure which shows the further another example of the tab in a bipolar battery. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the schematic diagram of the assembled battery which connected the bipolar battery of this invention in 2 series 20 parallel, Comprising: (a) is a top view, (b) is a front view, (c) is a side view. It is a figure which shows the assembled battery which connected the bipolar battery and 10 series of general lithium ion secondary batteries B in parallel, Comprising: (a) is a top view, (b) is a front view, (c) is a side view. It is a figure which shows the schematic diagram of the composite assembled battery which connected the assembled battery shown by FIG. 18 in parallel, Comprising: (a) is a top view, (b) is a front view, (c) is a side view. It is a schematic diagram which shows the electric vehicle of the state which mounts a composite assembled battery. It is a figure which shows the structure and evaluation result of the bipolar battery of an Example , a reference example, and a comparative example.

Explanation of symbols

1 Bipolar battery,
3 Bipolar electrodes,
3a top layer electrode,
3b, the bottom electrode,
5 electrolyte layer,
7 Insulating layer,
9 Power generation elements,
11, 11a-11k tab,
13, 13a-13k tabs,
19 Battery exterior material (polymer metal composite film),
19a skin resin layer,
19b metal layer,
19c resin layer between metal layer and tab,
21 polymer adhesive layer,
31, 31a, 31b, 31c hole-shaped part,
32 Outer edge,
35 concave shaped part,
50, 50 'battery pack,
60 composite battery pack,
70 electric car,
A bipolar battery,
B General lithium ion secondary battery,
A ₁ bonding area,
D ₁ , D ₂ insulation distance.

Claims (12)

A power generation element having a plurality of combinations of a positive electrode layer and a negative electrode layer;
A polymer metal composite film as an exterior material covering the power generation element;
Having a tab taken out from the inside of the polymer metal composite film,
In the adhesive region between the tab and the polymer metal composite film, the tab includes a hole-shaped portion that is linear across the adhesive region, and the longitudinal direction of the hole-shaped portion is relative to the longitudinal direction of the bipolar battery. A bipolar battery characterized by being inclined at a predetermined angle . The metal layer of the polymer metal composite film in the adhesion region is substantially flat,
2. The bipolar battery according to claim 1, wherein in the adhesion region, the tab includes a portion where an insulation distance between the tab and the metal layer is different from each other.   3. The bipolar battery according to claim 1, wherein in the adhesion region, a pair of outer edges located on both sides of the tab in the width direction form one straight line. 4. The hole shape portion, said at adhesive area, the bipolar battery according to any one of claims 1 to 3, characterized in that it is formed is separated into at least two in the extraction direction of the tab. 5. The bipolar battery according to claim 4 , wherein the positions of the separated hole-shaped portions in a direction orthogonal to the tab take-out direction are shifted from each other at least partially. Wherein the periphery of the tub in the bonding region, the bipolar battery according to any one of claims 1-5, characterized in that it further comprises at least one or more layers of the polymer adhesive layer. The cross-sectional area of the tabs in the adhesion area, the bipolar battery according to any one of claims 1-6, characterized in that said at least equivalent sectional area of the tabs in the outer adhesive region. The positive electrode layer, the bipolar battery according to any one of claims 1-7, characterized in that it comprises a Li-Mn-based composite oxide. The negative electrode layer is a bipolar battery according to any one of claims 1-8, characterized in that it comprises a crystalline carbon material or non-crystalline carbon material. An assembled battery comprising a plurality of the bipolar batteries according to any one of claims 1 to 9 connected in series, in parallel, or in a mixture of series and parallel. The bipolar battery according to any one of claims 1 to 9 ,
A battery having the same voltage as that of the bipolar battery by connecting the bipolar battery with the same material as the positive electrode layer and the negative electrode layer, and by connecting in series the number of structural units in the power generation element of the bipolar battery,
A battery pack characterized by being connected in parallel. A plurality of assembled battery according to claim 1 0 or 1 1, series, composite assembled battery, characterized in that parallel, or complexed connected in series with the parallel.

Images