JP2010086900A - Current collector, bipolar type electrode, bipolar cell, battery pack, and vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current collector capable of limiting a flow of a current in a face-direction of the current collector. <P>SOLUTION: The current collector 23 is the plate-like current collector 23 to constitute a battery electrode, and includes a first semiconductor region 23p and a second semiconductor region 23n. The first semiconductor region 23p includes a first conductive type. The second semiconductor region 23n is arranged neighboring the first semiconductor region 23p in the face-direction of the current collector 23, and includes a second conductive type different from the first conductive type. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a current collector, a bipolar electrode, a bipolar battery, an assembled battery, and a vehicle.

  Secondary batteries such as lithium batteries and nickel metal hydride batteries are actively developed as power sources for driving motors of electric vehicles (EV) and hybrid electric vehicles (HEV). As a secondary battery, a bipolar battery capable of realizing a high output density has attracted attention (for example, Patent Document 1).

A bipolar battery is formed by laminating a plurality of bipolar electrodes each having a positive electrode active material layer formed on one surface of a current collector and a negative electrode active material layer formed on the other surface via a separator. . In such a bipolar battery, a single battery layer is formed by a pair of bipolar electrodes adjacent to each other in the stacking direction via a separator, and the bipolar battery has a configuration in which a plurality of single battery layers are connected in series. Have.
JP-A-4-248274

  However, the bipolar battery has a problem that when an internal short circuit occurs between adjacent electrodes, a current flows toward the short circuit part in the surface of the current collector, and the temperature of the battery rises. Such an increase in battery temperature may cause the battery function to stop.

  The present invention has been made to solve the above-described problems. Therefore, the objective of this invention is providing the electrical power collector and bipolar electrode which can restrict | limit the flow of the electric current in the surface direction of an electrical power collector.

  Another object of the present invention is to provide a bipolar battery and an assembled battery in which temperature rise is suppressed.

  Still another object of the present invention is to provide a vehicle using the bipolar battery and the assembled battery.

  The above object of the present invention is achieved by the following means.

  The current collector of the present invention is a plate-like current collector that constitutes a battery electrode, and includes a first semiconductor region and a second semiconductor region. The first semiconductor region has a first conductivity type. The second semiconductor region is disposed adjacent to the first semiconductor region in the surface direction of the current collector, and has a second conductivity type different from the first conductivity type.

  The bipolar electrode of the present invention includes the current collector, a positive electrode active material layer formed on one surface of the current collector, a negative electrode active material layer formed on the other surface of the current collector, Have

  The bipolar battery of the present invention is formed by laminating a plurality of the bipolar electrodes with a separator interposed therebetween.

  In the assembled battery of the present invention, a plurality of the bipolar batteries are connected in series, in parallel, or a combination of series and parallel.

  The vehicle of the present invention is equipped with the bipolar battery or the assembled battery as a driving power source.

  According to the current collector and bipolar electrode of the present invention, the flow of current in the surface direction of the current collector is limited by the rectifying action of the first and second semiconductor regions adjacent to each other.

  According to the bipolar battery and the assembled battery of the present invention, current concentration at the short-circuit portion at the time of an internal short circuit is suppressed, so that the temperature rise of the battery is prevented.

  According to the vehicle of the present invention, since the temperature rise of the battery is prevented, the reliability is improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol was used for the same member in the figure.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a bipolar battery according to an embodiment of the present invention. In the bipolar battery of the present invention, the current flow in the thickness direction of the current collector is maintained while the current flow in the thickness direction of the current collector is restricted by giving the current collector a rectifying function. It is. Note that the bipolar battery of the present embodiment is, for example, a lithium secondary battery.

  As shown in FIG. 1, the bipolar battery 10 of the present embodiment is configured such that a power generating element 20 that generates electric power is housed inside an exterior member 30. Electrode tabs 41 and 42 for taking out the electric power generated by the power generation element 20 are provided at the end of the exterior member 30.

  The power generation element 20 has a flat rectangular shape, and a plurality of bipolar electrodes 21 are stacked with separators 22 interposed therebetween. The bipolar electrode 21 includes a single plate-like current collector 23, a positive electrode active material layer (hereinafter referred to as a positive electrode) 24 formed on one surface of the current collector 23, and the other of the current collectors 23. Negative electrode active material layer (hereinafter referred to as negative electrode) 25 formed on the surface. The current collector 23 of the present embodiment includes a first semiconductor region having a p-type conductivity type and a second semiconductor region having an n-type conductivity type that are arranged adjacent to each other. A detailed description of the current collector 23 will be described later. Note that the positive electrode active material and the negative electrode active material are the same as materials used in a general lithium secondary battery, and thus detailed description thereof is omitted.

  The plurality of bipolar electrodes 21 are stacked such that the positive electrode 24 and the negative electrode 25 face each other with the separator 22 interposed therebetween. The positive electrode 24, the separator 22, and the negative electrode 25 disposed between the current collectors 23 adjacent in the stacking direction constitute a unit cell layer 26 as a minimum element for power generation. That is, in the bipolar battery 10 of the present embodiment, the plurality of single battery layers 26 are electrically connected in series via the current collector 23. A seal member 27 is provided between the current collectors 23 adjacent to each other in the stacking direction along the peripheral edge of the current collector 23 in order to prevent leakage of the electrolytic solution. A first end plate 28 having a negative electrode 25 formed thereon is disposed on the uppermost layer of the power generating element 20 via a separator 22, and a second end plate having a positive electrode 24 formed on the lowermost layer. 29 is arranged via the separator 22. The first and second end plates 28 and 29 are led out of the exterior member 30 and constitute a negative electrode tab 41 and a positive electrode tab 42.

  The exterior member 30 has a flat rectangular shape and is formed of first and second exterior members 30a and 30b having electrical insulation. The first exterior member 30a has a recess for accommodating the power generation element 20, and the second exterior member 30b is connected to the first exterior member 30a so as to sandwich the power generation element 20 at the peripheral edge of the recess. They are joined together by thermal fusion. The first and second exterior members 30a and 30b are laminated films composed of three-layer sheets, and are provided with a heat fusion layer, a metal layer, and an outermost layer from a joint surface joined to each other to the surface. Have.

  Next, the current collector 23 in the present embodiment will be described in detail with reference to FIG.

  FIG. 2 is a diagram for explaining a current collector in the bipolar battery shown in FIG. 1. 2A is a top view of the current collector in the bipolar battery shown in FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB in FIG. 2A. As described above, the current collector 23 of the present embodiment has a rectifying function that limits the current flow in the plane direction while maintaining the current flow in the thickness direction.

  As shown in FIG. 2A, the current collector 23 in the present embodiment includes a first semiconductor region 23p and a second semiconductor region 23n which are formed of a rectangular plate material and have different conductivity types. . The first semiconductor region 23p has a p-type conductivity type in which holes are used as charge carriers, and the second semiconductor region 23n has an n-type conductivity type in which electrons are used as charge carriers. The first semiconductor region 23p and the second semiconductor region 23n are each formed in a rectangular shape, and the plurality of first and second semiconductor regions 23p, 23n are grid-like in the surface direction of the current collector 23. Are arranged alternately and continuously. Further, as shown in FIG. 2B, the first and second semiconductor regions 23p and 23n are formed over the entire thickness direction of the current collector 23.

  The first and second semiconductor regions 23p and 23n are adjacent to each other in the plane of the current collector 23, and form a pn junction at the boundary. The first and second semiconductor regions 23p and 23n forming the pn junction function as a diode that limits the flow of current in the surface direction of the current collector 23. More specifically, in the first and second semiconductor regions 23p and 23n, a current flow from the first semiconductor region 23p to the second semiconductor region 23n is allowed, while the second semiconductor region 23n. Current flow from the first to the first semiconductor region 23p is limited.

  In the current collector 23 of the present embodiment in which a plurality of first and second semiconductor regions 23p and 23n having such a rectifying function are arranged in a grid pattern, the current diffusion in the surface direction of the current collector 23 is reduced. Is prevented. More specifically, the plurality of first and second semiconductor regions 23p and 23n does not allow current flow in the surface direction of the current collector 23 unless a voltage higher than a predetermined on-voltage is applied. Current diffusion in the surface direction of the electric body 23 is prevented.

  On the other hand, current flow is allowed in the thickness direction of the current collector 23 in which one of the first and second semiconductor regions 23p and 23n is formed. That is, in the current collector 23 of the present embodiment, current diffusion in the plane direction is prevented by the first and second semiconductor regions 23p and 23n formed adjacent to each other in the plane direction. Current flow in the thickness direction is allowed. In other words, the current collector 23 of the present embodiment is provided with anisotropy of electrical conductivity so that the resistivity in the surface direction is larger than the resistivity in the thickness direction of the current collector 23.

  Next, the manufacturing process of the current collector 23 in the present embodiment will be described.

The current collector 23 of the present embodiment is formed by adding two kinds of impurities to a plate material made of polysilicon. Specifically, first, a polysilicon substrate that serves as a base material for the current collector is prepared. The polysilicon substrate has a thickness of 1 to 100 μm, and preferably has a p ⁻ type conductivity. Next, a p-type first semiconductor region 23p is formed by implanting B (boron) ions into the polysilicon substrate using a mask having an opening corresponding to the first semiconductor region. Then, using a mask having an opening corresponding to the second semiconductor region, P (phosphorus) ions are implanted into the polysilicon substrate, thereby forming an n-type second semiconductor region 23n. From the viewpoint of reducing the electrical resistance in the thickness direction of the current collector, it is preferable that the current collector is thin, such as the thickness of the substrate used for the current collector and the type of ions implanted into the substrate. Accordingly, the ion dose is determined. In addition, since the process itself which inject | pours a dopant into a polysilicon substrate is a general ion implantation process, detailed description is abbreviate | omitted. Unlike the present embodiment, for example, the first and second semiconductor regions may be formed by a thermal diffusion method in which an impurity is deposited on the substrate surface and then thermally diffused.

Examples of the substrate used for the current collector of this embodiment include polysilicon, amorphous silicon, metal oxide, and conductive polymer. Examples of the metal oxide include ITO, ZnO, SnO, CdO, and CdGa ₂ O _4, and examples of the conductive polymer include an organic semiconductor and pentacene. Examples of the dopant added to the substrate include p-type dopants such as B, Al, and Ga for polysilicon and amorphous silicon, and n-type dopants such as N, P, As, and Sb. Can be mentioned. For ZnO, p-type dopants such as P and N are exemplified, and n-type dopants such as Ga, Al, In, and F are exemplified. However, since ZnO has n-type conductivity, the first and second semiconductor regions can be formed by adding only the p-type dopant to the ZnO substrate as shown in FIG. Similarly, since CdO has n-type conductivity, the first and second semiconductor regions can be formed by adding only a p-type dopant such as Zn to the CdO substrate.

  Next, the effect of the current collector 23 in the present embodiment will be described with reference to FIG. FIG. 4 is a diagram showing current-voltage characteristics in the surface direction of the current collector in the bipolar battery shown in FIG. In FIG. 4, for reference, a case where a general current collector is used is shown as a comparative example. The solid line in FIG. 4 represents the current-voltage characteristic of the current collector in the present embodiment, and the broken line represents the current-voltage characteristic of a general metal current collector. Also, the alternate long and short dash line in FIG. 4 represents the current-voltage characteristics of the current collector formed from a conductive resin.

  As indicated by the dashed line and the alternate long and short dash line in FIG. 4, in the current collector made of metal and conductive resin, the current flow in the surface direction of the current collector is not limited, and thus is proportional to the voltage applied to the current collector. A current flows in the surface direction of the current collector. Note that a current collector made of a conductive resin has a higher electrical resistivity than a metal current collector, and thus the current flowing in the surface direction can be reduced by making the film thinner. However, current spreading in the surface direction of the current collector cannot be prevented even with a current collector made of conductive resin. Therefore, in the current collector made of metal and conductive resin, when an internal short circuit occurs between the electrodes, the current concentrates on the short circuit part and the temperature of the bipolar battery is increased.

  On the other hand, as shown by the solid line in FIG. 4, in the current collector 23 of the present embodiment, a plurality of pn junctions are formed by the first semiconductor regions 23p and the second semiconductor regions 23n that are alternately arranged. Therefore, the current flow in the surface direction is limited. More specifically, the plurality of first and second semiconductor regions 23p and 23n constitute a switching element having an on-voltage (for example, 20V) higher than the voltage (about 4V) of the lithium cell layer. The plurality of first and second semiconductor regions 23p and 23n prevent current from flowing in the surface direction of the current collector 23 in the applied voltage region lower than the on-voltage. Note that such an on-voltage increases as the number of the first and second semiconductor regions 23p and 23n increases.

  According to the current collector 23 and the bipolar electrode 10 of the present embodiment configured as described above, the current flow in the thickness direction is maintained, while the current diffusion in the plane direction is prevented. . Therefore, even when an internal short circuit occurs due to an external impact or the like, it is possible to prevent current from flowing in the surface direction of the current collector and current from concentrating on the short circuit portion. As a result, even if an internal short circuit occurs, a temperature increase of the bipolar battery due to current concentration at the short circuit part is prevented.

  Next, the assembled battery and the vehicle in the present embodiment will be described with reference to FIGS. 5 and 6.

  The bipolar battery 10 described above can be connected in series or in parallel to form a battery module 50, and the battery modules 50 can be further connected in series or in parallel to form an assembled battery 60. The battery module 50 is formed by stacking a plurality of bipolar batteries 10 and storing them in a module case, and connecting the bipolar batteries 10 in parallel. FIG. 5 is a perspective view of the assembled battery in the present embodiment. The produced battery modules 50 are connected to each other using an electrical connection member such as a bus bar, and are stacked in a plurality of stages. The number of bipolar batteries 10 used in the assembled battery 60 and the number of stacked battery modules 50 are determined according to the battery capacity and output of the vehicle on which the battery is mounted.

  FIG. 6 is a schematic configuration diagram showing an electric vehicle as a vehicle in the present embodiment. The bipolar battery 10, the battery module 50, and / or the assembled battery 60 described above can be mounted on a vehicle such as an automobile and a train and used as a power source for driving an electric device such as a motor. As shown in FIG. 6, the electric vehicle 70 according to the present embodiment has the assembled battery 60 mounted under the seat at the center of the vehicle body. The drive wheels are rotated by the motor supplied with electric power from the assembled battery 60, and the electric vehicle 70 travels.

  In the electric vehicle 70 having such a configuration, even when an internal short circuit occurs, the temperature increase of the bipolar battery 10 and the assembled battery 60 is prevented, so the battery function does not stop, and the electric vehicle 70 Reliability is improved.

(Modification)
Next, a modification of the current collector in the present embodiment will be described with reference to FIGS. 7-9 is a figure which shows the modification of the electrical power collector in the bipolar battery shown in FIG.

  As shown in FIG. 7, in the current collector 23 of this modification, the first and second semiconductor regions 23p and 23n are formed in a strip shape, and a plurality of first and second semiconductor regions are formed along one direction. 23p and 23n are alternately arranged continuously. FIG. 7A shows an embodiment in which the first and second semiconductor regions 23p and 23n are alternately arranged along the longitudinal direction of the rectangular current collector 23. FIG. In this embodiment, the first and second semiconductor regions 23p and 23n are arranged along the width direction of the current collector 23. FIG. 7C shows an embodiment in which the first and second semiconductor regions 23p and 23n are alternately and continuously arranged along the direction inclined with respect to the longitudinal direction of the current collector 23. is there.

  Further, as shown in FIG. 8, the strip-like first and second semiconductor regions 23p and 23n may be formed so as to form a closed space, and may be alternately arranged. In the modification shown in FIG. 8, for example, the second semiconductor region 23n having a higher resistivity than the first semiconductor region 23p is formed to have a larger width. Further, from the viewpoint of preventing variation in the current flowing in the thickness direction of the current collector 23, the first and second semiconductor regions 23p and 23n in the present modification may be periodically formed at a predetermined interval. preferable.

  According to the current collector 23 configured in this manner, the current along the one direction is caused by the plurality of first and second semiconductor regions 23p and 23n arranged alternately along the one direction. Flow is limited. Then, the first and second semiconductor regions 23p and 23n can be formed relatively easily as compared with the above embodiment in which the first and second semiconductor regions 23p and 23n are arranged in a grid pattern. .

  As yet another modification, as shown in FIG. 9, the second semiconductor region 23n is formed so that the first semiconductor region 23p is formed in a lattice shape and surrounded by the lattice-shaped first semiconductor region 23p. A plurality of may be formed.

  As described above, the described embodiment has the following effects.

  (A) The current collector of this embodiment includes a first semiconductor region having a p-type conductivity type and an n-type conductivity disposed adjacent to the first semiconductor region in the surface direction of the current collector. A second semiconductor region having a mold. Therefore, the current flow in the surface direction of the current collector can be limited by the rectifying action of the first and second semiconductor regions adjacent to each other.

  (B) The first and second semiconductor regions are formed over the entire thickness direction of the current collector. Therefore, the current flow in the surface direction of the current collector can be more strictly limited.

  (C) The first and second semiconductor regions are each formed in a rectangular shape, and a plurality of first and second semiconductor regions are alternately arranged in a grid pattern. Therefore, the flow of current in two different directions can be restricted in the plane of the current collector. Further, the current diffusion path can be reduced by reducing the size of the rectangular first and second semiconductor regions.

  (D) The first and second semiconductor regions are each formed in a strip shape, and a plurality of first semiconductor regions and second semiconductor regions are alternately and continuously arranged. Therefore, the flow of current in the direction perpendicular to the belt-like first and second semiconductor regions can be restricted in the plane of the current collector. In addition, the first and second semiconductor regions can be formed relatively easily.

  (E) The first semiconductor region is formed in a lattice shape, and a plurality of second semiconductor regions are formed so as to be surrounded by the lattice-shaped first semiconductor region. Therefore, the current flow in the surface direction of the current collector can be limited.

  (F) The first and second semiconductor regions are periodically arranged at a predetermined interval. Therefore, variation in current flowing in the thickness direction of the current collector can be prevented. As a result, variations in temperature distribution in the surface of the current collector can be suppressed.

  (G) The first and second semiconductor regions are formed by adding at least one impurity to a plate made of polysilicon, amorphous silicon, metal oxide, or a conductive polymer. Therefore, a current collector having the first and second semiconductor regions can be formed. Further, the resistivity of the first and second semiconductor regions can be adjusted by controlling the amount of impurities added.

  (H) The bipolar electrode according to the present embodiment includes the current collector, a positive electrode active material layer formed on one surface of the current collector, and a negative electrode active material formed on the other surface of the current collector. And a layer. Therefore, the current flow in the surface direction of the current collector can be limited.

  (I) The bipolar battery of the present embodiment is formed by laminating a plurality of the bipolar electrodes with a separator interposed therebetween. Therefore, current concentration at the short-circuit portion at the time of internal short-circuit is suppressed, so that the temperature increase of the bipolar battery is prevented.

  (J) The assembled battery of the present embodiment is formed by connecting the bipolar batteries in series, in parallel, or a combination of series and parallel. Therefore, current concentration at the short-circuit portion at the time of an internal short circuit is suppressed, so that the temperature rise of the assembled battery is prevented.

  (K) The electric vehicle of this embodiment is equipped with the bipolar battery or the assembled battery as a driving power source. Therefore, the temperature rise of the battery is prevented, and the reliability is improved.

  As described above, the current collector, bipolar electrode, bipolar battery, assembled battery, and vehicle of the present invention have been described in the above-described embodiment. However, it goes without saying that the present invention can be appropriately added, modified, and omitted by those skilled in the art within the scope of the technical idea.

  For example, in the above-described embodiment, the first and second semiconductor regions are formed over the entire thickness direction of the current collector. However, the first and second semiconductor regions are not necessarily formed over the entire thickness direction of the current collector, and may be formed by adding impurities to a predetermined depth. In this case, the lower regions of the first and second semiconductor regions to which no impurity is added are reduced in thickness and increased in resistivity by the first and second semiconductor regions. The current flowing through can be suppressed.

  In the above-described embodiment, the first and second semiconductor regions are periodically formed at predetermined intervals on the substrate. However, the first and second semiconductor regions can be formed in various sizes and concentrations depending on the position in the plane of the current collector. In this case, for example, the size (width) of the first and second semiconductor regions is small at the center of the current collector, and the size (width) of the first and second semiconductor regions at the peripheral portion of the current collector. Can be formed to be large. Alternatively, for example, the first and second semiconductor regions may be formed so that the concentration of the dopant is higher in the central portion of the current collector than in the peripheral portion.

  In addition, the shape of the first and second semiconductor regions is not limited to the above embodiment, and for example, a p-type dopant is implanted into a circular shape or an elliptical shape into a substrate having an n-type conductivity, and the semiconductor The region may be formed in an island shape.

  In the above-described embodiment, the negative electrode and the positive electrode are directly formed on the uppermost and lowermost end plates of the power generation element, respectively. However, a current collector may be provided between the end plate, the negative electrode, and the positive electrode.

  Hereinafter, embodiments of the present invention will be described in more detail using examples. However, the present invention is not limited at all by this example.

P / N / P / N / P / N / P in which four first semiconductor regions and three second semiconductor regions are alternately and continuously arranged on a polysilicon substrate having a thickness of 3 μm. A repeating structure was formed. The first semiconductor region having the p-type conductivity was formed by implanting B ions into the polysilicon substrate with an ion implantation energy of 50 keV and a dose of 1 × 10 ¹⁵ atoms / cm ² . The second semiconductor region having the n-type conductivity was formed by implanting P ions with an ion implantation energy of 50 keV and a dose amount of 3.8 × 10 ¹⁴ ions / cm ² .

  When a voltage was applied to both ends of the polysilicon substrate thus formed to measure a voltage value at which a current began to flow (that is, an ON voltage), it was 20 V in both the forward direction and the reverse direction. Since the voltage of the electric power generated in the single battery layer of the lithium secondary battery is about 4 V, the current collector made of the polysilicon substrate in which the plurality of first and second semiconductor regions are alternately formed It was confirmed that no current flows in the direction of the body.

It is sectional drawing which shows schematic structure of the bipolar battery in one embodiment of this invention. It is a figure for demonstrating the electrical power collector in the bipolar battery shown in FIG. It is a figure for demonstrating the modification of the electrical power collector in the bipolar battery shown in FIG. It is a figure which shows the electric current-voltage characteristic of the surface direction of the electrical power collector in the bipolar battery shown in FIG. It is a perspective view of the assembled battery using the bipolar battery shown in FIG. It is a schematic block diagram which shows the electric vehicle using the bipolar battery shown in FIG. It is a figure which shows the modification of the electrical power collector in the bipolar battery shown in FIG. It is a figure which shows the modification of the electrical power collector in the bipolar battery shown in FIG. It is a figure which shows the modification of the electrical power collector in the bipolar battery shown in FIG.

Explanation of symbols

10 Bipolar battery,
20 power generation elements,
21 Bipolar electrode,
22 separator,
23 current collector,
23p first semiconductor region,
23n second semiconductor region,
24 cathode active material,
25 negative electrode active material,
26 cell layer,
30 exterior member,
41, 42 electrode tabs,
50 battery module,
60 battery packs,
70 Electric car (vehicle).

Claims (11)

A plate-like current collector constituting a battery electrode,
A first semiconductor region having a first conductivity type, and a second conductivity type that is disposed adjacent to the first semiconductor region in a plane direction of the current collector and is different from the first conductivity type. And a second semiconductor region having the current collector.   The current collector according to claim 1, wherein the first and second semiconductor regions are formed over the entire thickness direction of the current collector. The first and second semiconductor regions are each formed in a rectangular shape,
The current collector according to claim 1, wherein the plurality of first and second semiconductor regions are alternately arranged in a grid pattern. The first and second semiconductor regions are each formed in a band shape,
The current collector according to claim 1, wherein a plurality of the first semiconductor regions and the second semiconductor regions are alternately and continuously arranged.   3. One of the first and second semiconductor regions is formed in a lattice shape, and the other is formed in plural so as to be surrounded by the lattice-shaped semiconductor region. The current collector described in 1.   The current collector according to any one of claims 3 to 5, wherein the first and second semiconductor regions are periodically arranged at a predetermined interval.   The first and second semiconductor regions are formed by adding at least one impurity to a plate made of polysilicon, amorphous silicon, metal oxide, or a conductive polymer. Item 7. The current collector according to any one of Items 1 to 6. The current collector according to any one of claims 1 to 7,
A positive electrode active material layer formed on one surface of the current collector;
And a negative electrode active material layer formed on the other surface of the current collector.   A bipolar battery according to claim 8, wherein a plurality of the bipolar electrodes according to claim 8 are laminated via a separator.   An assembled battery comprising a plurality of bipolar batteries according to claim 9 connected in series, parallel, or a combination of series and parallel.   A vehicle comprising the bipolar battery according to claim 9 or the assembled battery according to claim 10 as a driving power source.

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