Bipolar electrode, electrode assembly containing the same, bipolar battery containing the electrode assembly, and method for manufacturing the bipolar battery.

Abstract

This disclosure relates to a bipolar electrode comprising a current collector including a polymer film and a conductive layer added to at least a portion of the outer and inner surfaces of the polymer film, a positive electrode formed on a first surface of the current collector, and a negative electrode formed on a second surface of the current collector, wherein the current collector made of polymer film is heat-fused to create a sealed form, thereby preventing the movement of electrolyte between the unit electrodes.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0027781, filed on February 27, 2024, and all the contents disclosed in the Korean patent application are incorporated herein by reference.

[0002] The present disclosure relates to a bipolar electrode, an electrode assembly including the same, a bipolar battery including the electrode assembly, and a method for manufacturing the bipolar battery. Specifically, it relates to a bipolar electrode in which the structure of the current collector of the bipolar electrode is changed to simplify means for preventing the movement of an electrolyte between stacked bipolar electrodes, an electrode assembly including the same, a bipolar battery including the electrode assembly, and a method for manufacturing the bipolar battery.

Background Art

[0003] Due to global abnormal weather phenomena, the net-zero clock is gradually getting faster, and the movement to replace fossil fuels with environmentally friendly energy is increasing. Therefore, lithium secondary batteries are replacing fossil fuels as one of the environmentally friendly energies.

[0004] Lithium secondary batteries can also be used as an energy source for devices that require a lot of energy, such as electric vehicles, due to their advantages of high energy density and high output. Therefore, the proportion of lithium secondary batteries applied in various fields is increasing.

[0005] Lithium secondary batteries include a general form of monopolar electrode in which electrode binders of the same polarity are coated on both sides of a current collector, or a bipolar electrode in which active materials having different polarities are coated on both sides of a current collector.

[0006] Bipolar electrodes have the advantage of forming a high potential due to their structure in which the positive and negative electrodes are stacked so as to be connected in series, and thus can achieve high energy density and high output.

[0007] In an electrode assembly where bipolar electrodes are stacked, if electrolyte moves and mixes between different bipolar electrodes, self-discharge and bipolar current can occur. Therefore, a structure is needed to prevent the electrolyte from moving between bipolar electrodes and to separate the electrolyte.

[0008] Furthermore, when multiple bipolar electrodes are stacked, the current collectors of the bipolar electrodes may come into contact with each other, or if uneven areas occur at the ends of the bipolar electrodes, the electrode active material layer and the current collector may come into contact at those areas. This can cause unexpected short circuits.

[0009] Therefore, conventionally, in order to fix the current collectors of bipolar electrodes, structures have been proposed such as applying adhesive between the current collectors or placing a separate component around the outside of the current collector and applying adhesive to fix the separate component.

[0010] Patent Document 1 discloses a bipolar current collector comprising a base film and a first conductive layer and a second conductive layer coated on both sides of the base film. In this invention, a positive electrode material and a negative electrode material are attached to the first and second conductive layers, and a conductive sealing film comprising a sealing conductive layer and a polymer layer is provided at both ends of the base film. Each end of the sealing conductive layer of the conductive sealing film is connected to the first and second conductive layers, and the polymer layer is added so as to surround the outside of the sealing conductive layer and is connected to the first and second conductive layers.

[0011] Patent Document 1 presents a structure in which a current collector includes a base film coated with a first conductive layer and a second conductive layer on both sides, and a conductive sealing film is connected to the current collector but is insulated from adjacent bipolar electrodes, thereby preventing the movement of the electrolyte. However, for this configuration, Patent Document 1 requires that, in addition to the current collector, a conductive sealing film including a sealing conductive layer and a polymer layer be provided separately.

[0012] Patent Document 2 describes a bipolar lithium secondary battery including a bipolar unit, in which a polymer film attached to the edge of the current collector terminal separates the electrolyte adjacent to electrodes having different polarities, and prevents the mutual movement of the separated electrolytes.

[0013] However, Patent Document 2 only describes a configuration that requires a separate polymer film in addition to the current collector.

[0014] Therefore, there is a need for a technology that can prevent the electrolyte from moving between bipolar electrodes in electrode assemblies and bipolar batteries that include bipolar electrodes, without requiring any additional structures beyond the basic bipolar electrode configuration. [Prior art documents] [Patent Documents]

[0015] [Patent Document 1] Chinese Patent Publication No. 112687842 [Patent Document 2] Korean Patent Publication No. 10-2020-0143281 [Overview of the Initiative] [Problems that the invention aims to solve]

[0016] This disclosure aims to solve the aforementioned problems and provides a bipolar electrode that can prevent the movement of electrolyte between bipolar electrodes while simplifying the structure of the bipolar electrode by adding a conductive layer to the center and applying a heat-sealable polymer film to the outer periphery as a current collector for the bipolar electrode, an electrode assembly including the same, a bipolar battery including the electrode assembly, and a method for manufacturing the bipolar battery. [Means for solving the problem]

[0017] The bipolar electrode according to the present disclosure for achieving such an object may include a current collector including a polymer film and a conductive layer added to at least a part of the outer surface and the inner surface of the polymer film, a positive electrode formed on a first surface of the current collector, and a negative electrode formed on a second surface of the current collector.

[0018] The polymer film may include a first region having through holes into which conductive substances of the conductive layers added to both outer surfaces flow and are accommodated, and a second region located on the outer periphery of the first region and having no through holes.

[0019] The conductive layer may be added to the first region of the first surface and the second surface.

[0020] The positive electrode may be located on the conductive layer of the first surface, and the negative electrode may be located on the conductive layer of the second surface.

[0021] A separator may be further added to an outer surface of either one of the positive electrode and the negative electrode.

[0022] The separator may be heat-sealed to at least a part of the positive electrode or the negative electrode to which the separator is added and the second region of the polymer film.

[0023] The present disclosure provides an electrode assembly formed by laminating the bipolar electrodes. In the electrode assembly, the outer peripheries of the polymer films of the current collectors may be heat-sealed to each other.

[0024] Unit electrodes partitioned by the heat-sealed outer peripheries of the polymer films are formed, and the electrolytic solution injected into the unit electrodes may be separated from the electrolytic solution injected into other adjacent unit electrodes.

[0025] The uppermost bipolar electrode has an electrode layer formed only on the lower surface of the current collector, the lowermost bipolar electrode has an electrode layer formed only on the upper surface of the current collector, and for the remaining bipolar electrodes excluding the uppermost bipolar electrode and the lowermost bipolar electrode, a positive electrode may be formed on the first surface of the current collector and a negative electrode may be formed on the second surface.

[0026] A support member is further disposed in the second region of the current collector, and the support member can be thermally fused to the second region of the current collector.

[0027] The present disclosure provides a bipolar battery in which the electrode assembly is housed in a battery case, and in the bipolar battery, the uppermost bipolar electrode and the lowermost bipolar electrode can include electrode terminals.

[0028] The present disclosure provides a method for manufacturing the bipolar battery. Specifically, the method can include a first step of preparing bipolar electrodes, a second step of stacking the bipolar electrodes to manufacture an electrode assembly, a third step of heating three of the four outer peripheral sides of the electrode assembly excluding one of the outer peripheral sides to thermally fuse the current collector, a fourth step of injecting an electrolytic solution into the electrode assembly, a fifth step of heating the one outer peripheral side to thermally fuse the current collector, and a sixth step of housing the electrode assembly in a battery case and sealing the battery case.

[0029] The first step can include a first - 1 step of preparing a polymer film, a first - 2 step of coating conductive layers on the first regions on both sides of the polymer film to manufacture a current collector, a first - 3 step of disposing a positive electrode on the first region of the first surface of the current collector and disposing a negative electrode on the first region of the second surface of the current collector, and a first - 4 step of laminating a separator film on the upper surface of either the positive electrode or the negative electrode.

[0030] The uppermost bipolar electrode and the lowermost bipolar electrode of the electrode assembly include electrode terminals.

[0031] Furthermore, this disclosure can also be provided in a form that combines various means for solving the aforementioned problems. [Effects of the Invention]

[0032] This disclosure relates to a polymer film current collector in which conductive layers are formed on both sides of the polymer film in the portions where the positive and negative electrodes are coated, and electrical connections are formed so that electrons move within the conductive layers, and the outer periphery of the polymer film in which the positive and negative electrodes are not coated can be sealed by heat fusion.

[0033] Therefore, not only is a series connection formed between the positive and negative electrodes via the polymer film, but the movement of electrolyte between adjacent unit electrodes can also be blocked. [Brief explanation of the drawing]

[0034] [Figure 1] This is a disassembled perspective view of a bipolar electrode according to this disclosure. [Figure 2] Figure 1 is an exploded view of the bipolar electrode in a vertical cross-section. [Figure 3] This is a vertical cross-sectional view of the bipolar electrode of the present disclosure with a separation membrane attached. [Figure 4] This is a cross-sectional view of an electrode assembly in which bipolar electrodes are stacked according to the first embodiment. [Figure 5] Figure 4 is a perspective view showing the process of thermally welding the electrode assembly. [Figure 6] This is a cross-sectional view of an electrode assembly in which bipolar electrodes are stacked according to the second embodiment. [Figure 7] Figure 6 is a perspective view showing the process of thermally bonding the electrode assembly. [Modes for carrying out the invention]

[0035] Hereinafter, with reference to the attached drawings, embodiments will be described in detail that will allow a person with ordinary skill in the art to easily implement the present disclosure. In describing the operating principles of the embodiments of the present disclosure in detail, if it is determined that a specific description of a related known function or configuration may unnecessarily obscure the gist of the present disclosure, such detailed description will be omitted.

[0036] Throughout the drawings, the same reference numerals shall be used for parts that have similar functions and operations. In the specification, when it is said that one part is connected to another part, this includes not only direct connection but also indirect connection through other elements in between. Furthermore, when it is said that a component is included, unless otherwise stated, it does not mean that other components are excluded, but rather that other components may be included.

[0037] Descriptions that limit or specify the constituent elements are applicable to all inventions and are not limited to a particular invention, unless otherwise specified.

[0038] Throughout this disclosure and the claims, singular nouns include plural nouns unless otherwise noted.

[0039] Throughout the description and claims of this invention, "or" includes "and" unless otherwise specified. Therefore, "including A or B" means three cases: including A, including B, or including both A and B.

[0040] This disclosure will be described in detail with reference to the attached drawings, along with the examples provided.

[0041] Figure 1 is an exploded perspective view of the bipolar electrode according to this disclosure, and Figure 2 is an exploded vertical cross-sectional view of the bipolar electrode of Figure 1.

[0042] Generally, bipolar electrodes are configured such that a positive electrode mixture layer and a negative electrode mixture layer are added to each side of a current collector, allowing electron transfer between the positive and negative electrodes via the current collector, and current flows in the thickness direction of the electrodes within the battery cell. However, if electrolyte is transferred across the current collector of the bipolar electrode, there is a risk of internal short circuits, so it is necessary to block the movement of electrolyte between adjacent unit electrodes.

[0043] Referring to Figures 1 and 2, the bipolar electrode according to this disclosure has a positive electrode 200 located on a first surface 121 of the current collector 100 and a negative electrode 300 located on a second surface 122. The current collector 100 includes a polymer film 110 and a conductive layer 120, the polymer film 110 including a first region 111 having through-holes into which conductive material of the conductive layer 120 added to both outer surfaces flows and is contained, and a second region 112 located outside the first region 111 and not having the through-holes.

[0044] The polymer film 110 may contain one or more materials selected from the group consisting of polyethylene terephthalate (PET), polypropylene, polyethylene, polystyrene, polyvinyl chloride, polyimide, and polyamide.

[0045] The through-holes are configured such that the conductive material of the conductive layer added to the outer surface of the polymer film penetrates the polymer film and moves to the opposite outer surface. For example, the first region may be configured as a mesh structure.

[0046] The diameter of the through-hole can range from several tens of micrometers to several millimeters, but its size is not particularly limited as long as it is large enough for the conductive material of the conductive layer added to each side of the polymer film to flow in and pass through.

[0047] However, if the size of the through-hole is too small, conductive material will not flow easily, and if the size of the through-hole is too large, there is a risk of breakage when the bipolar electrode is bent, which is undesirable.

[0048] The conductive layer 120 is added to at least a portion of the outer and inner surfaces of the polymer film 110, and to the first region 111 of the first surface 121 and second surface 122 of the current collector 100. Therefore, the conductive material constituting the conductive layer 120 can be added to at least a portion of the surface of the first region 111 and the through holes formed in the first region 111. In this way, by adding the conductive material to the outer surface and the inner surface of the through holes of the insulating polymer film 110, it can function as an electrically conductive current collector. Furthermore, since the conductive material added to the first region 111 fills the inside of the through holes, the conductive material added to each of the outer surfaces on both sides of the polymer film 110 is connected through the through holes, thereby forming an electrical connection passage.

[0049] The positive electrode 200 is located on the conductive layer 120 of the first surface 121, and the negative electrode 300 is located on the conductive layer 120 of the second surface 122.

[0050] In the current collector 100 located between the positive electrode 200 and the negative electrode 300, the first region 111 of the polymer film 110 is filled with conductive material in through holes, so that electrons can move between the positive electrode 200 and the negative electrode 300 via the conductive material and form a series connection.

[0051] On the other hand, the second region 112 is a region where the positive electrode 200 and the negative electrode 300 are not placed, and since the polymer film 110 does not have through holes, the second region 112 can be heat-fused after lamination as an electrode assembly. When the outer periphery of the current collector is heat-fused in this way, an independent space is formed between the current collectors of adjacent bipolar electrodes.

[0052] Since the components arranged within these independent spaces constitute individual unit electrodes, it is possible to prevent the electrolyte from moving between adjacent unit electrodes.

[0053] On the other hand, the conductive layer 120 formed on the first surface 121 of the current collector 100 and the conductive layer 120 formed on the second surface 122 may be made of the same material or different materials.

[0054] For example, the conductive layer 120 formed on the first surface 121 and the conductive layer 120 formed on the second surface 122 may be composed of one selected from the group consisting of aluminum, copper, and nickel.

[0055] Alternatively, the conductive layer 120 formed on the first surface 121 where the positive electrode 200 is placed may be made of aluminum, and the conductive layer 120 formed on the second surface 122 where the negative electrode 300 is placed may be made of copper.

[0056] Figure 3 is a vertical cross-sectional view of the bipolar electrode of this disclosure with a separation membrane attached.

[0057] Referring to Figure 3, a separation membrane 400 is further added to the bipolar electrode. When multiple bipolar electrodes are stacked to form an electrode assembly, physical contact between the bipolar electrodes can be blocked by the separation membrane 400.

[0058] Figure 3(a) shows the separation membrane 400 attached to the upper surface of the positive electrode 200. It goes without saying that, conversely, the separation membrane 400 can also be attached to the lower surface of the negative electrode 300.

[0059] In this way, the separation film 400 attached to the outer surface of the positive electrode 200 or the negative electrode 300 can be bonded to the positive or negative electrode by heat fusion.

[0060] Figure 3(b) shows a configuration in which a separation membrane 400 is added that extends not only to the upper surface of the positive electrode 200 but also to the second region 112 of the polymer film of the current collector 100.

[0061] As shown in Figure 3(b), even when an extended separation membrane 400 is added, the separation membrane 400 can be added not only to the upper surface of the positive electrode, but also to the lower surface of the negative electrode 300 and to the second region 112 of the polymer film of the current collector 100.

[0062] The separation film 400 can be heat-fused to the surface of the positive electrode 200 or the negative electrode 300 and the second region 112. This ensures stable adhesion between the electrode to which the separation film is attached and the current collector.

[0063] A method for manufacturing a bipolar electrode according to this disclosure includes: a 1-1 step of preparing a polymer film; a 1-2 step of manufacturing a current collector by coating a conductive layer on first regions on both sides of the polymer film; a 1-3 step of arranging a positive electrode in a first region on the first surface of the current collector and a negative electrode in a first region on the second surface of the current collector; and a 1-4 step of laminating a separation film on the upper surface of either the positive electrode or the negative electrode.

[0064] Additionally, by further including the steps of arranging a positive electrode and a negative electrode on the current collector, laminating a separation film, and then heating and pressing the bipolar electrode, the separation film can be fused to the surface of the bipolar electrode.

[0065] Figure 4 shows an electrode assembly in which bipolar electrodes are stacked according to the first embodiment.

[0066] Referring to Figure 4, the electrode assembly 1000 has a configuration in which bipolar electrodes in the form shown in Figure 3(a) are stacked.

[0067] In Figure 4, the upper diagram shows an electrode assembly 1000 manufactured by stacking multiple bipolar electrodes, while the lower diagram shows the state in which the current collector 100 of the electrode assembly 100 is heated and the second region, which is the outer periphery of the current collector 100, is thermally fused.

[0068] The electrode assembly 1000 consists of three stacked bipolar electrodes 1100, each having a positive electrode 200 on the upper surface of a current collector 100 and a negative electrode 300 on the lower surface. The uppermost bipolar electrode 1200 has the negative electrode 300 located only on the lower surface of the current collector 100, while the lowermost bipolar electrode 1300 has the positive electrode 200 located only on the upper surface of the current collector 100.

[0069] In the electrode assembly 1000 shown in Figure 4, the number of bipolar electrodes 1100 can be changed as needed.

[0070] The uppermost bipolar electrode 1200 and the lowermost bipolar electrode 1300 of the electrode assembly 1000 include electrode terminals.

[0071] The electrode terminal includes an electrode lead or an electrode tab, and the electrode terminal may include a main body portion coupled to the uppermost bipolar electrode and the lowermost bipolar electrode, having an area equal to or smaller than the plane area of ​​the uppermost bipolar electrode and the lowermost bipolar electrode, and an extension portion extending from the main body portion outward on one side and protruding beyond the outer periphery of the uppermost bipolar electrode and the lowermost bipolar electrode.

[0072] Specifically, the uppermost bipolar electrode 1200 of the electrode assembly 1000 contains only a negative electrode, and the lowermost bipolar electrode 1300 contains only a positive electrode. Therefore, the negative electrode terminal 301 is connected to the upper surface of the uppermost bipolar electrode 1200, and the positive electrode terminal 201 is connected to the lower surface of the lowermost bipolar electrode 1300.

[0073] Unlike those shown in Figure 4, the positive terminal 201 and the negative terminal 301 may include a main body that is sized to cover the entire uppermost bipolar electrode 1200 and the lowermost bipolar electrode 1300, and an extension that extends from the main body outward on one side and protrudes to the outside of the battery case when housed in the battery case.

[0074] Alternatively, the area of ​​the main body is configured to cover at least a portion of the outer surface of the uppermost bipolar electrode 1200 and the lowermost bipolar electrode 1300, and the extension is configured to protrude outside the electrode case.

[0075] In such a case, since the electrode assembly 1000 including the bipolar electrodes is connected in series between the electrodes, when the electrode assembly 1000 is housed in a battery case, it can be configured so that only the positive terminal 201 and negative terminal 301 attached to each end of the bipolar electrodes connected in series extend outside the battery case.

[0076] By heating the outer periphery of the electrode assembly 1000, the outer periphery of the polymer film 110 of the current collector 100 is heat-fused to each other. In this way, the polymer film 110 is heat-fused to form a pocket-shaped space 510, and the inside and outside of the pocket-shaped space 510 are separated from each other. In this way, a unit electrode 500 is formed, with the space 510 partitioned by the polymer film as a single unit. When electrolyte is individually injected into the unit electrode 500 and the outer periphery of the polymer film 110 is heat-fused, the electrolyte injected into the unit electrode 500 is separated from the electrolyte injected into other adjacent unit electrodes.

[0077] The method for manufacturing a bipolar battery according to this disclosure includes: a first step of preparing bipolar electrodes; a second step of stacking the bipolar electrodes to manufacture an electrode assembly; a third step of heating the remaining three outer peripheries of the electrode assembly, excluding one outer periphery out of the four outer peripheries, to thermally fuse the current collector; a fourth step of pouring an electrolyte into the electrode assembly; a fifth step of heating the remaining one outer periphery to thermally fuse the current collector; and a sixth step of housing the electrode assembly in a battery case and sealing the battery case.

[0078] Figure 5 is a perspective view showing the process of thermally bonding the electrode assembly shown in Figure 4.

[0079] Referring to Figure 5, after stacking bipolar electrodes to prepare the electrode assembly shown in Figure 4, as shown in Figure 5(a), the outer periphery 112a, 112b, and 112c of the four outer periphery of the electrode assembly are pressed and heated to form a pocket-shaped space in which only the outer periphery 112d in one direction is open. The reason why only the outer periphery 112d in one direction is not heat-fused is that the electrolyte will be poured into this area.

[0080] As shown in Figure 5(b), the electrolyte is injected in the direction of the arrow. Here, the electrolyte is injected individually into each of the pocket-shaped spaces.

[0081] Figure 5(c) shows the state after the outer periphery 112d has been pressed and heated to form a heat-sealed bond.

[0082] Although not shown in Figure 5, the electrode assembly is then placed in the battery case and sealed.

[0083] As the battery case, a pouch-type case made of a laminate sheet containing a resin layer and a metal layer, or a rectangular case made of metal material can be used.

[0084] On the other hand, as shown in Figure 5(a), a bipolar battery can be manufactured by first housing an electrode assembly with three outer perimeters 112a, 112b, and 112c heat-fused together into a battery case, then pouring electrolyte into the inside of the electrode assembly, and finally heat-fusing the outer perimeter 112d of the electrode assembly and sealing the battery case.

[0085] Thus, the bipolar battery according to this disclosure includes a current collector in the form of a polymer film with a through-hole only in the center, to which a conductive layer is added to the surface. Therefore, the outer periphery of the polymer film without the through-hole can be heat-fused to form a partitioned space. Thus, a series connection can be formed between adjacent bipolar electrodes, and the movement of electrolyte between adjacent unit electrodes can be blocked.

[0086] Figure 6 shows an electrode assembly in which bipolar electrodes are stacked according to the second embodiment.

[0087] Referring to Figure 6, the electrode assembly including the bipolar electrode according to the second embodiment differs from the electrode assembly including the bipolar electrode according to the first embodiment shown in Figure 4 in that a support member 600 is added between the current collectors 100.

[0088] The support member 600 is positioned in the second region of the current collector 100 to maintain the shape of the electrode assembly and block the movement of the electrolyte. Its material is not particularly limited as long as it does not cause side reactions with the electrolyte. For example, it may be composed of one or more materials selected from the group consisting of polyethylene terephthalate (PET), polypropylene, polyethylene, polystyrene, polyvinyl chloride, polyimide, and polyamide, and more specifically, it may be composed of the same material as the polymer film.

[0089] Figure 6 shows the height of the support member 600 as corresponding to the sum of the thicknesses of the negative electrode 300, the separation membrane 400, and the positive electrode 200. However, it goes without saying that the height of the support member 600 may be smaller than the sum of the thicknesses of the negative electrode 300, the separation membrane 400, and the positive electrode 200.

[0090] If a support member 600 is added, the upper and lower surfaces of the support member 600 can be heat-fused to the second region of the current collector 100.

[0091] Furthermore, the description of the electrode assembly with stacked bipolar electrodes according to the second embodiment can be similarly applied to the description of the electrode assembly with stacked bipolar electrodes according to the first embodiment.

[0092] Figure 7 is a perspective view showing the process of thermally bonding the electrode assembly shown in Figure 6.

[0093] Referring to Figure 7, since the support member 600 is configured in a square frame shape, when stacking bipolar electrodes, the bipolar electrodes and support members can be stacked alternately such that the support member 600 is positioned between the current collectors 100. Subsequently, as shown in Figure 7(a), the outer periphery 112a, 112b, and 112c of the four outer periphery of the electrode assembly are pressed and heated to form a pocket-shaped space in which only the outer periphery 112d in one direction is open, by thermal fusion.

[0094] The electrolyte is injected in a state where the current collector 100 and the support member 600 are deformed so that a gap is created between them in the unidirectional outer peripheral area 112d where heat fusion did not occur. Here, the electrolyte is injected individually into each of the pocket-shaped spaces.

[0095] After the electrolyte injection is complete, the outer peripheral 112d in one direction is pressed and heated to heat-seal it.

[0096] Although not shown in Figure 7, the electrode assembly is then placed in the battery case and sealed.

[0097] On the other hand, as shown in Figure 7(a), a bipolar battery can be manufactured by first housing an electrode assembly with three outer perimeters 112a, 112b, and 112c heat-fused together into a battery case, then pouring electrolyte into the inside of the electrode assembly, and finally heat-fusing the outer perimeter 112d of the electrode assembly and sealing the battery case.

[0098] Furthermore, the description of the electrode assembly with stacked bipolar electrodes according to the second embodiment can be similarly applied to the description of the electrode assembly with stacked bipolar electrodes according to the first embodiment, so the detailed contents will be omitted.

[0099] A person with ordinary skill in the field to which this disclosure belongs will be able to make various applications and modifications within the scope of this disclosure based on the foregoing. [Explanation of Symbols]

[0100] 100 Current collector 110 Polymer Film 111 First area 112 Second area 112a, 112b, 112c, 112d Outer perimeter 120 Conduction layer 121 Page 1 122 2nd page 200 positive electrode 201 Positive terminal 300 negative electrode 301 Negative terminal 400 Separation membrane 500 unit electrodes 510 Space 600 Support member 1000 electrode assembly 1100, 1200, 1300 bipolar electrodes

Claims

1. A current collector comprising a polymer film and a conductive layer added to at least a portion of the outer and inner surfaces of the polymer film, The positive electrode formed on the first surface of the current collector, The negative electrode formed on the second surface of the current collector, A bipolar electrode, including one.

2. The polymer film is A first region having through holes into which the conductive material of the conductive layer added to both outer surfaces flows and is contained, The bipolar electrode according to claim 1, comprising: a second region located outside the first region and lacking the through-hole.

3. The bipolar electrode according to claim 2, wherein the conductive layer is added to the first region of the first and second surfaces.

4. The bipolar electrode according to claim 3, wherein the positive electrode is located on the conductive layer of the first surface and the negative electrode is located on the conductive layer of the second surface.

5. The bipolar electrode according to claim 1, wherein a separation film is further added to the outer surface of either the positive electrode or the negative electrode.

6. The bipolar electrode according to claim 5, wherein the separation membrane is heat-fused to at least a portion of the positive or negative electrode to which the separation membrane is attached, and the second region of the polymer film.

7. An electrode assembly comprising stacked bipolar electrodes according to any one of claims 1 to 6, The bipolar electrode is an electrode assembly in which the outer periphery of the polymer film of the current collector is heat-fused to each other.

8. A unit electrode is formed, demarcated by the heat-fused outer periphery of the polymer film. The electrode assembly according to claim 7, wherein the electrolyte injected into the unit electrode is separated from the electrolyte injected into other adjacent unit electrodes.

9. The uppermost bipolar electrode has an electrode layer formed only on the lower surface of the current collector. The lowest bipolar electrode has an electrode layer formed only on the upper surface of the current collector. The electrode assembly according to claim 8, wherein the remaining bipolar electrodes, excluding the uppermost bipolar electrode and the lowermost bipolar electrode, have a positive electrode formed on the first surface of the current collector and a negative electrode formed on the second surface.

10. A support member is further arranged in the second region of the current collector. The electrode assembly according to claim 7, wherein the support member is heat-fused to the second region of the current collector.

11. A bipolar battery comprising an electrode assembly according to claim 7 housed in a battery case, A bipolar battery in which the electrode assembly includes electrode terminals for the uppermost bipolar electrode and the lowermost bipolar electrode.

12. A method for manufacturing a bipolar battery according to claim 11, The first step is to prepare the bipolar electrodes, A second step involves stacking the aforementioned bipolar electrodes to manufacture an electrode assembly, A third step involves heating the remaining three outer perimeters of the electrode assembly, excluding one of the four outer perimeters, to heat-seal the current collector. A fourth step involves pouring an electrolyte solution into the electrode assembly, A fifth step involves heating the outer periphery of one side to heat-seal the current collector, A sixth step involves housing the electrode assembly in the battery case and sealing the battery case, A method for manufacturing a bipolar battery, including [the specified part of the invention].

13. The first stage is, Step 1-1 involves preparing the polymer film, The first and second steps involve manufacturing a current collector by coating a conductive layer on a first region on both sides of the polymer film, The first to third steps involve placing a positive electrode in a first region on the first surface of the current collector and a negative electrode in a first region on the second surface of the current collector, Steps 1-4 include laminating a separation membrane on the upper surface of either the positive electrode or the negative electrode, A method for manufacturing a bipolar battery according to claim 12, including the following:

14. The method for manufacturing a bipolar battery according to claim 12, wherein the uppermost bipolar electrode and the lowermost bipolar electrode of the electrode assembly include electrode terminals.

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