Prevention of air trap formation during fabrication of bipolar stacked battery

Abstract

SOLUTION: A bipolar stacked battery that prevents air entrapment during formation of a bipolar stacked battery includes a plurality of stacked battery cells. An electrically and ionically insulating frame is formed between each of the plurality of stacked battery cells.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Related Applications This patent application is related to U.S. Provisional Application No. 63 / 555,484, entitled "Preventing Air Trap Formation During the Fabrication of Bipolar Stacked Batteries," filed February 20, 2024, in the names of the same inventors, and is incorporated herein by reference in its entirety. This patent application claims the benefit under 35 U.S.C. § 119(e) of the aforementioned provisional application.

[0002] Technical Field FIELD OF THE DISCLOSURE This disclosure relates generally to batteries, and more particularly to bipolar stacked batteries and methods of formation that prevent air entrapment during formation of the bipolar stacked batteries. [Background technology]

[0003] Background of the Invention Electric vehicles (EVs) are becoming increasingly popular in the market as an alternative to traditional internal combustion engine vehicles, mainly due to their environmentally friendly nature and advanced technological features. The operation of an EV relies heavily on its battery system, which provides the electrical energy required to power the motor.

[0004] Traditionally, multiple batteries can be connected in series to generate sufficient voltage to power a high-torque motor in a vehicle. However, this design has several inherent drawbacks. One drawback, for example, is that a significant number of joining components can be required to stack batteries in series. Joining components not only contribute to energy and power density losses due to volume loss, but also introduce additional resistance, which can lead to reduced power density. Furthermore, joining components tend to concentrate current around the joining area, which can result in uneven temperature and current distribution throughout the battery. This can ultimately contribute to premature battery system degradation.

[0005] To address these challenges, bipolar batteries have been developed. In these bipolar batteries, the positive and negative electrodes are located on opposite sides of the current collector, significantly reducing the need for connecting components. However, these bipolar batteries come with their own set of problems. Specifically, they can present a risk of short circuits; if the current collectors of different layers come into contact, the battery cell cannot produce the required voltage, resulting in a drop in overall voltage. Similarly, if the electrolytes of different battery layers come into contact, the cell may also be unable to generate the required voltage.

[0006] U.S. Patent Publication 2015 / 0255797A1 discloses a method for forming bipolar batteries in which the ends of the battery units are covered with an insulating polymer to prevent electrical shorts. The problem with this method is that this approach still risks delamination or bubble formation at the interface between the current collector and the electrode (cathode or anode) due to the sealed environment created by the polymer insulator.

[0007] It is therefore desirable to provide a system and method that overcomes the above. Summary of the Invention

[0008] Summary of the Invention This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description of the Invention. This Summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0009] According to one embodiment of the present invention, a bipolar battery stack that prevents air entrapment during formation of the bipolar battery stack is disclosed. The bipolar battery stack includes a plurality of stacked battery cells, and an electrically and ionically insulating frame is formed between each of the plurality of stacked battery cells.

[0010] According to one embodiment of the present invention, a method for forming a bipolar battery stack that prevents air entrapment during formation of the bipolar battery stack is disclosed, the method including forming an electrically and ionically insulating frame between each of a plurality of stacked battery cells of the bipolar battery stack.

[0011] According to one embodiment of the present invention, a bipolar stacked battery that prevents air from being trapped during formation of the bipolar stacked battery is disclosed. The bipolar stacked battery has a plurality of stacked battery cells. An electrical and ionically insulating frame is formed between each of the plurality of stacked battery cells. The insulating frame is arranged in each of the plurality of stacked battery cells so that at least one end of each of the plurality of stacked battery cells is open so as not to completely seal each of the plurality of stacked battery cells. The separators of each stacked battery cell and the inner end of the insulating frame have similar shapes. The area (S) formed by the outer end of the insulating frame is f,outer ) is the area of ​​the current collector (S cc ) or more, and for each stacked battery cell, 1≦(S f,outer / S cc ) is satisfied. The area formed by the inner edge of the insulating frame of each stacked battery cell (S f,inner ) and the separator area (S sep ) is 0.8≦(S f,inner / S sep )≦1.43, where the thickness (T) of each stacked battery cell of the plurality of stacked battery cells and the thickness (t) of the insulating frame satisfy 0.05≦(t / T)≦1.22.

[0012] BRIEF DESCRIPTION OF THE DRAWINGS The present application will be described in further detail with reference to the following drawings, which are not intended to limit the scope of the present application, but rather to illustrate certain attributes thereof. The same reference numbers are used throughout the drawings to refer to the same or similar parts. [Brief explanation of the drawings]

[0013] [Figure 1A]FIG. 1A illustrates a cross-sectional side view of an exemplary bipolar stacked battery according to an embodiment of the present disclosure;

[0014] [Figure 1B] FIG. 1B is an exploded view of an exemplary battery cell of the bipolar stacked battery of FIG. 1A according to an embodiment of the present disclosure;

[0015] [Figure 2] FIG. 2 illustrates a cross-sectional side view of an exemplary bipolar stacked battery according to an embodiment of the present disclosure;

[0016] [Figure 3] FIG. 3 is an enlarged cross-sectional view of an exemplary battery cell of the bipolar stacked battery of FIG. 1A according to an embodiment of the present disclosure; and

[0017] [Figure 4] FIG. 4 is another exploded view of an exemplary battery cell of the bipolar stacked battery of FIG. 1A, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0018] Detailed Description of the Invention The following description is intended to describe presently preferred embodiments of the present disclosure and is not intended to represent the only mode in which the present disclosure can be constructed and / or utilized. The description sets forth the functions and sequence of steps for constructing and operating the present disclosure. However, it should be understood that the same or equivalent functions and sequences may be accomplished by different embodiments that are intended to be within the spirit and scope of the present disclosure.

[0019] This patent application proposes a system and method for forming a bipolar stacked battery cell. The bipolar stacked battery cell may have an electrically and ionically insulating frame. The insulating frame may be either freestanding or affixed to one side of the current collector, but not necessarily to both sides (top and bottom) of the current collector. The ends of the bipolar stacked battery cell may not be completely sealed. The insulator may not seal the ends of the bipolar stacked cell. This may avoid trapping air bubbles in the stack during the manufacturing process, thus leading to improved cell performance.

[0020] 1A-1B, a stacked bipolar battery cell 7 (hereinafter referred to as stacked cell 7) can be shown. From the high-voltage side to the low-voltage side, the stacked cell 7 can be formed from layers of a current collector 1, a cathode layer 2, a separator 4, and an anode layer 3. This formation can be repeated so that the stacked cell 7 can have a layer formation of 1, 2, 4, 3, 1, 2, ..., 2, 4, 3, 1. As can be seen in FIGS. 1A-1B, an insulating frame 5 can be sandwiched by the current collector 1 along with the stack of the cathode layer 2, the separator 4, and the anode layer 3. The insulating frame 5 does not need to have electronic or ionic conductivity. As can be seen in FIGS. 1A-1B, the insulating frame 5 can cover the edges of the current collector 1, the cathode layer 2, the anode layer 3, and the separator 4. That is, any layer between the electrical stacks need not contact any other layer.

[0021] In order to avoid trapping gases in the stacked cells 7, particularly at the interface between the current collector 1 and the cathode layer 2 (or anode layer 3), the insulating frame 5 should not completely seal the ends of the stacked cells 7. The insulating frame 5 may be a free-standing frame. Alternatively, the insulating frame 5 may have adhesive on one side of its surface and be attached to the current collector 1 as shown in FIG. 2. When the insulating frame 5 is attached to one of the internal current collectors 1, the insulating frame 5 is not attached to both the upper and lower current collectors 1 of the stacked cells 7.

[0022] The components of the laminated cell 7 may need to meet certain conditions to avoid significant deformation of the current collector 1 during the manufacturing process of the laminated cell 7. Referring to FIG. 3 , the laminate thickness (T) may be defined as the sum of the thicknesses of the current collector 1, the cathode layer 2, the separator 4, the anode layer 3, and the current collector 1. The laminate thickness T should satisfy the relationship with the thickness (t) of the insulating frame 5, 0.05≦(t / T)≦1.22.

[0023] The area of ​​the separator 4 is preferably larger than that of the cathode layer 2 and the anode layer 3. The area (S f,outer ) is the area of ​​the current collector (S cc ) or more. That is, 1≦(S f,outer / S cc )

[0024] The area formed by the inner edge of the insulating frame 5 (S f,inner ) and the area of ​​separator 4 (S sep ) is 0.8≦(S f,inner / S sep )≦1.43 can be satisfied.

[0025] The current collector 1 may be made of metal foil, metal mesh, or similar materials. In some embodiments, metal foil may be used. Examples of metals that may be used for the current collector 1 include, but are not limited to, Cu, Ni, Cr, Au, Pt, Ag, Au, Al, Fe, Ti, Zn, Co, and stainless steel. The material may be a pure metal element, doped, alloyed, or clad. The surface of the metal may be coated with carbon or other materials. This may help ensure good adhesion with the cathode layer 2 and anode layer 3. In addition to metals, carbon may also be used for the current collector 1. Resin composites with electronic conductors (metals, carbon, or metal-coated plastics) as fillers may be used for the current collector 1. Possible carbon filler materials include, but are not limited to, acetylene black (AB), ketjen black (KB), VGCF, carbon nanotubes, carbon nanohorns, graphite, acicular graphite, and fullerenes. Possible filler metals include, but are not limited to, stainless steel, Cu, Ni, Cr, Au, Pt, Ag, Au, Al, Fe, Ti, Zn, and Co. The shape of the filler can be spherical, fibrous, needle-like, hollow, or similar. When needle-like or fibrous fillers are used, it can be effective to orient the filler, as this orientation helps control the flow of electrons and interrupt current in the event of an abnormality.

[0026] There is no particular limitation on the thickness of the current collector 1. According to an embodiment, the thickness of the current collector 1 can be 0.1 μm to 1 mm, more specifically 1 μm to 50 μm.

[0027] The cathode layer 2 may be a layer that may contain at least a cathode active material (CAM). Examples of CAM include layered lithium-containing oxide materials (LiCoO, LiMnO, LiNiO, LiNi x Mn y Co 1-x-y O2, LiNi x Co y Al 1-x-y O2, etc.), lithium-containing phosphates with an olivine structure (LiFePO4, LiFex Mn 1-x PO4, LiMnPO4, LiFe x Co 1-x PO4, LiCoPO4, etc.), lithium-containing oxide materials with spinel structure (LiNi 0.5 Mn 1.5 O4, LiMn2O4, etc.), lithium-rich layered oxides (Li2MnO3, Li2RuO3, Li2Ru x Ti 1-x O3, Li2Ru x Sn 1-x O3, Li2Mn x Ti 1-x O3, Li2Mn x Sn 1-x O3, etc.), layered lithium-containing sulfide materials (TiS2, MoS2, NbS2, TaS2, sulfur, etc.), or lithium-containing sulfides with a Chevrel structure (LiCu x MoS 1-z These may include, but are not limited to:

[0028] The surface of the CAM may be coated with a thin layer (coating) of material. Examples of coating materials may include, but are not limited to, crystalline phases (LiZrO, LiNbO, LiPO, LiPO, LiTi(PO), LiZr(PO), ZrO, AlO, EtOLi, MtOLi, LiOH, LiCO, etc.) and / or amorphous phases (metal alkoxides, metal phosphates, etc.).

[0029] In addition to the CAM, the cathode layer 2 may further include a solid electrolyte, a binder, and an electronically conductive additive. Examples of the electrolyte may include, but are not limited to, an organic liquid, an organic polymer, and an inorganic solid. According to an embodiment, the electrolyte may be an inorganic solid because it has a higher lithium transference number than a liquid and higher ionic conductivity than an organic polymer. This may be because inorganic solids are typically hard and do not exhibit flowability, making them preferable for constructing a stacked cell 13 without ionic short circuits.

[0030] According to an embodiment, examples of electrolytes include Li-PON, Li-Si-O, Li-B-Si-O, Li-BO, Li-CBO, Li-Al-Si-O, Li-Ti-Al-PO, Li-Zr-Al-PO, Li-La-Zr-O, Li-La-Ta-Zr-O, Li-La-Nb-Zr-O, Li-MS (wherein M is B, Al, Si, P, Zn, Ge, Zr, Sn, or a combination thereof), Li-M'-SO (wherein M' is B, Al, Si, P, Zn, Ge, Zr, Sn, or a combination thereof), Li-PSX (wherein X is F, Cl, Br, or a combination thereof), and Li-PSX (wherein X is F, Cl, Br, or a combination thereof). The materials may include, but are not limited to, materials having a composition of Li-PSO-X' (X' is F, Cl, Br or a combination thereof), Li-BH, Li-BNH, Li-BHO, Li-BNHO, Li-M"-X" (M is In, Zr, Sc, Ga, Nb, Ta or a combination thereof; X" is F, Cl, Br or a combination thereof), Li-M"-X"-O (M" is In, Zr, Sc, Ga, Nb, Ta or a combination thereof; X" is F, Cl, Br or a combination thereof).

[0031] Examples of binders that can be included in the cathode layer 2 include, but are not limited to, butadiene rubber (BR), butyl rubber (IIR), acrylate butadiene rubber (ABR), polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE). The side chains of the binder can be modified with functional groups.

[0032] In addition, the cathode layer 2 may contain an electron-conducting additive. For example, various types of carbon may be used, including acetylene black (AB), Ketjen black (KB), VGCF, carbon nanotubes, carbon nanohorns, graphite, acicular graphite, and fullerenes.

[0033] The thickness of the cathode layer 2 is not particularly limited, but when a higher capacity is required, a thicker layer may be preferable. For example, according to an embodiment, the thickness of the cathode layer 2 may be 0.1 μm to 1 mm, and more preferably 60 μm to 500 μm.

[0034] The anode layer 3 is a layer that may contain at least an anode active material (AAM). Examples of AAM include layered lithium-containing sulfide materials (TiS, MoS, NbS, TaS, etc.), titanium-containing oxides (LiTiO, etc.), and the like. 12 , Ti x Nb y O z , Li x Ti2(PO4)3, etc.), tungsten-containing oxides (Nb 16 W5O 55 , Nb 18 W 16 O 93 etc.), vanadium-containing oxides (LiVO2 etc.), artificial carbon (or hard carbon), graphite, Li-metal alloys (Li x In, Li x Sn, Li x Si, Li x Ge, Li x Al), or metallic lithium.

[0035] In addition to the AAM, the anode layer 3 may further include a solid electrolyte, a binder, and an electronically conductive additive.

[0036] Examples of the electrolyte may include, but are not limited to, an organic liquid, an organic polymer, or an inorganic solid. According to an embodiment, the electrolyte is an inorganic solid because it has a higher lithium transference number compared to a liquid and a higher ionic conductivity than an organic polymer. This is because inorganic solids are typically hard and do not exhibit flowability, making them preferable for constructing stacked cells 7 without ionic short circuits.

[0037] According to embodiments, examples of electrolytes include Li-PON, Li-Si-O, Li-B-Si-O, Li-BO, Li-CBO, Li-Al-Si-O, Li-Ti-Al-PO, Li-Zr-Al-PO, Li-La-Zr-O, Li-La-Ta-Zr-O, Li-La-Nb-Zr-O, Li-MS (wherein M is B, Al, Si, P, Zn, Ge, Zr, Sn, or a combination thereof), Li-M'-SO (wherein M' is B, Al, Si, P, Zn, Ge, Zr, Sn, or a combination thereof), Li-PSX (wherein X is F, Cl, Br, or a combination thereof), and Li-MS (wherein M is B, Al, Si, P, Zn, Ge, Zr, Sn, or a combination thereof). The materials may include, but are not limited to, materials that may have a composition of Li-PSO-X' (X' is F, Cl, Br, or a combination thereof), Li-BH, Li-BNH, Li-BHO, Li-BNHO, Li-M"-X" (M" is In, Zr, Sc, Ga, Nb, Ta, or a combination thereof; X" is F, Cl, Br, or a combination thereof), Li-M"-X"-O (M" is In, Zr, Sc, Ga, Nb, Ta, or a combination thereof; X" is F, Cl, Br, or a combination thereof).

[0038] Examples of binders that may be included in the anode layer 3 include, but are not limited to, butadiene rubber (BR), butyl rubber (IIR), acrylate butadiene rubber (ABR), polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE). The side chains of the binder may be modified with functional groups.

[0039] In addition, the anode layer 3 may contain an electronically conductive additive. For example, various types of carbon may be used, including acetylene black (AB), Ketjen black (KB), VGCF, carbon nanotubes, carbon nanohorns, graphite, acicular graphite, and fullerenes.

[0040] The thickness of the anode layer 3 is not particularly limited, but when higher capacity is required, a thicker layer may be preferred.

[0041] The separator 4 is an electronic insulator and an ion conductor. The electrolyte can be either an organic liquid, an organic polymer, or an inorganic solid. If an organic-based electrolyte (liquid or polymer) is selected, the separator 4 can be a porous membrane made of a polymer such as polyethylene (PE), polypropylene (PP), or a combination thereof. The membrane is immersed in the organic-based electrolyte.

[0042] According to an embodiment, the separator 4 may be made of an inorganic solid because it has a higher lithium transport number compared to liquids and a higher ionic conductivity than organic polymers. This may be because inorganic solids are usually hard and do not exhibit flowability, making them preferable for constructing a stacked cell 7 without ionic short circuits.

[0043] Examples of the electrolyte may include, but are not limited to, an organic liquid, an organic polymer, or an inorganic solid. According to an embodiment, the electrolyte is an inorganic solid because it has a higher lithium transference number than a liquid and has higher ionic conductivity than an organic polymer. This may be because inorganic solids are typically hard and do not exhibit flowability, making them preferable for constructing stacked cells 7 without ionic short circuits.

[0044] Examples of electrolytes include Li-PON, Li-Si-O, Li-B-Si-O, Li-BO, Li-CBO, Li-Al-Si-O, Li-Ti-Al-PO, Li-Zr-Al-PO, Li-La-Zr-O, Li-La-Ta-Zr-O, Li-La-Nb-Zr-O, Li-MS (wherein M is B, Al, Si, P, Zn, Ge, Zr, Sn, or a combination thereof), Li-M'-SO (wherein M' is B, Al, Si, P, Zn, Ge, Zr, Sn, or a combination thereof), Li-PSX (wherein X is F, Cl, Br, or a combination thereof), and Li-PSX (wherein X is F, Cl, Br, or a combination thereof). The materials may include, but are not limited to, materials having a composition of Li-PSO-X' (X' is F, Cl, Br, or a combination thereof), Li-BH, Li-BNH, Li-BHO, Li-BNHO, Li-M"-X" (M" is In, Zr, Sc, Ga, Nb, Ta, or a combination thereof; X" is F, Cl, Br, or a combination thereof), Li-M"-X"-O (M" is In, Zr, Sc, Ga, Nb, Ta, or a combination thereof; X" is F, Cl, Br, or a combination thereof).

[0045] The solid electrolyte layer may contain a binder in addition to the above-mentioned solid electrolyte material. Examples of binders that may be contained in the cathode layer 2 include, but are not limited to, butadiene rubber (BR), butyl rubber (IIR), acrylate butadiene rubber (ABR), polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE). The side chains of the binder may be modified with functional groups.

[0046] The thickness of the separator 4 is not particularly limited, but thinner layers may be preferable when higher capacity is required. For example, the thickness of the separator 4 may be 0.1 μm to 1 mm, more specifically 0.1 μm to 50 μm.

[0047] The insulating frame 5 can be fabricated to enhance the insulation between layers and thus enable the stacked cell 7 to achieve high voltages. The insulating frame 5 can be intricately positioned between the current collectors 1, carefully separating both their long and short sides. Its presence ensures that any surface area of ​​the current collector 1 not occupied by the cathode layer 2 or the anode layer 3 can be completely insulated. The insulating frame 5 does not need to adhere to any component of the stacked cell 7, but can be laminated to one side of the current collector 1 as shown in FIG. 2. If the insulating frame 5 has adhesive or sticky properties on its surface, it is important that the insulating frame 5 not completely seal the edges of the stacked cell 7 to avoid trapping air at the interface between the layers.

[0048] In terms of its electrical properties, the insulating frame 5 can be constructed to be an excellent insulator. -8 S / cm is preferable, but a stricter and more desirable threshold is 10 -10 S / cm, which may ensure that the insulating frame 5 functions optimally and provides maximum protection against any unwanted current.

[0049] The position of the insulating frame 5 is not bound by any strict restrictions. The guiding principle is that the current collector 1 should be comprehensively shielded. In practical terms, this may mean that the insulating frame 5 can grace both sides of the current collector 1, i.e., the side facing the cathode layer 2 and the side facing the anode layer 3.

[0050] While the exact area of ​​the insulating frame 5 on the surface of the current collector 1 is not strictly defined, it is desirable to adequately cover any area left exposed from the edge of the electrode active material layer. The key is to electronically insulate the surface of the current collector 1. However, it is important to avoid forming the insulating frame 5 on either the cathode layer 2 or the anode layer 3. Such an arrangement can be problematic during the bonding process when fabricating the stacked cell 7. The overlap between the electrode and the insulating frame can create areas of uneven pressure. Such pressure imbalances can damage the current collector or even the separator 4.

[0051] The gap or distance between the cathode layer 2 and the insulating frame 5 can be expressed as the width (r) of the exposed surface of the current collector 1, and can be adjusted to ensure insulation between the layers. While not limited by strict parameters, ideally, the width r should range from 0.0001% to 10% of the square root of S, where S represents the area of ​​the cathode layer 2 in cm 2 This ensures a balanced design that provides optimal insulation while maintaining the structural integrity and performance of the stacked cell 7. The criteria for the gap or distance between the cathode layer 2 and the insulating frame 5 are also applicable to the criteria for the gap or distance between the anode layer 3 and the insulating frame 5.

[0052] The material used for the insulating frame 5 is not limited to a specific material. The material used for the insulating frame 5 may have the required insulation properties. Examples of materials for the insulating frame 5 include, but are not limited to, acrylic (polyacrylic acid (PAA), poly(methyl methacrylate) (PMMA), etc.); acrylonitrile butadiene styrene (ABS); polyamide (PA); polyimide (PI); polyamideimide (PAI); polycarbonate (PC); polyoxymethylene (POM); polyether ether ketone (PEEK); polyetherimide (PEI); polyethylene (PE); polyethylene terephthalate (PET); polyphenylene oxide (PPO); polyphenylene sulfide (PPS); polypropylene (PP); polyvinyl chloride (PVC); polyvinylidene fluoride (PVDF); polytetrafluoroethylene (PTFE); ethylene tetrafluoroethylene (ETFE); fluorinated ethylene propylene (FEP); silicone rubber; and epoxy film.

[0053] If it is necessary to laminate an insulating frame 5 onto the surface of the current collector 1, an adhesive 6 may be used. The adhesive 6 should be a good insulator. Its electrical conductivity is 10 -8 S / cm, and a more stringent and desirable threshold is 10 -10 S / cm, which may ensure that the insulating frame 5 functions optimally and provides maximum protection against any unwanted current.

[0054] The area of ​​the adhesive 6 is not subject to strict limitations. The guiding principle is that the adhesive 6 should not completely seal the edges of the stacked cells 7. That is, the adhesive 6 can be placed on any surface of the insulating frame 5 as long as it allows gas to escape in the spaces between the current collectors 1.

[0055] The material used for the adhesive 6 is not limited to a specific material as long as the material has the required insulating ability. Examples of the adhesive 6 may include, but are not limited to, acrylics such as polyvinyl acetate (PVA); epoxy adhesives (EA); polyurethane adhesives (PA); cyanoacrylate adhesives (CA); hot melt adhesives (HMA); pressure-sensitive adhesives, etc. [Example]

[0056] Example 1: Air bubble trapping test The stacked cells 7 were manufactured using different types of insulating frames 5, and after manufacturing, the surface of the current collector 1 was checked to see if any air bubbles were trapped.

[0057] Fabrication of the cathode layer The cathode layer 2 used in this example was fabricated using a cathode active material (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Powders of PO2 (Mitsubishi Electrolyte Co., Ltd.), solid electrolyte (SSE-10, NEI), and PTFE (Daikin America) were mixed in a ratio of 87:12:1 (wt%). The mixture was then spread into a sheet with a thickness of 370 μm to form the cathode layer 2.

[0058] Fabrication of the anode layer The anode layer 3 used in this example was fabricated using an anode active material (Li4Ti5O 12 Powders of PET (MSE supplies LLC), solid electrolyte (SSE-10, NEI), carbon black (C45, Imerys), and PTFE (Daikin America) were mixed in a ratio of 80:15:1:4 (wt%). The mixture was then rolled out into a sheet with a thickness of 600 μm to form the anode layer 3.

[0059] Separator manufacturing The separator 4 used in this example was manufactured by mixing powders of a solid electrolyte (SSE-10, NEI) and PTFE (Daikin America) in a ratio of 97:3 (wt%). The mixture was then stretched into a sheet with a thickness of 150 μm to form the separator 4.

[0060] Bipolar stacked cell manufacturing The laminated cell 7 was fabricated by stacking unit cells consisting of an Al foil (34 mm diameter), an anode layer 3 (28 mm diameter), a separator 4 (30 mm diameter), a cathode layer 2 (22 mm diameter), and an Al foil (34 mm diameter). The unit cell had a ring-shaped insulating frame 5 (ID=30.6 mm, OD=34 mm) between the Al foils. The materials of the insulating frame 5 are listed in Table 1 below. Three unit cells were then stacked together and compressed in a uniaxial press with a force of 30 tons.

[0061] result The quality of the laminated cell 7 was examined by observing whether air bubbles were trapped between the current collector 1 and the cathode layer 2 or anode layer 3. The results of the examination are listed in Table 1 below.

[0062] When the insulating frame 5 had adhesive 6 and sealed the edges of the laminated cells 7, air bubbles were found in the laminated cells 7. However, when the frame was not sealed, the laminated cells 7 had no air bubbles. Table 1 [Table 1]

[0063] Example 2: Current collector deformation and short circuit test The cathode layer 2, the anode layer 3, and the separator 4 were fabricated using the same procedures as in Example 1. The dimensions of the insulating frame 5 were modified for pressing, as shown in Table 2 below. After the same densification procedures as in Example 1, the prepared laminated cell 7 was examined by visually observing the deformation of the current collector 1 and by measuring the open circuit voltage without charging to confirm short circuits. Table 2 [Table 2]

[0064] Mode 1: The current collector 1 was bent and inserted into the gap between the separator 4 and the inner edge of the insulating frame 5. As a result, the stacked cell 7 was short-circuited.

[0065] Mode 2: Due to deformation of the insulating frame 5 during the densification process, the current collectors 1 buckled up. The current collectors 1 contacted each other at the edges of the stacked cells 7, leading to a short circuit.

[0066] Aspect 3: The insulating frame 5 was too thin and loose. In this situation, the insulating frame 5 was not positioned properly (it could move almost freely). As a result, the current collectors 1 came into contact with each other at the positions where the insulating frame 5 should have been.

[0067] Mode 4: The current collectors 1 were bent at the ends of the insulating frame 5 and came into contact with each other.

[0068] The above disclosure provides a method for preventing air entrapment during the formation of a bipolar battery. 1. Bipolar stacked battery with an electrically and ionically insulating frame. 2. The ends of the bipolar stack are not completely sealed. 3. The insulating frame may be freestanding or affixed to one side of the current collector, but not necessarily to both sides (top and bottom) of the current collector. 4. The shape of each layer is not specified. For example, the shape can be a circle, a square, a rectangle, a hexagon, a trapezoid, etc. 5. The inner edges of the separator and insulating frame must be similar in shape, but the other layers do not necessarily have to be similar in shape. 6. The area of ​​the separator is larger than the area of ​​the cathode layer and the anode layer. 7. Area formed by the outer edge of the insulating frame (S f,outer ) is the area of ​​the current collector (S cc ) or more. That is, 1≦(S f,outer / S cc ) 8. Area formed by the inner edge of the insulating frame (S f,inner ) and the separator area (S sep ) is 0.8≦(S f,inner / S sep )≦1.43. 9. The thickness of a unit laminate (current collector + cathode layer + separator + anode layer + current collector) (T) and the thickness of the insulating frame (t) satisfy the relationship 0.05≦(t / T)≦1.22. 1 to 3 may be important to avoid forming air bubbles that become trapped at the interface of the current collector 1 and the cathode layer 2 or anode layer 3. 4 to 9 can be important to avoid significant deformation of the current collector during the densification step of the manufacturing process. Such significant deformation can cause short circuits.

[0069] The foregoing description is provided to enable any person skilled in the relevant art to practice the various embodiments described herein. Various modifications to these embodiments will be readily apparent to those skilled in the relevant art, and the general principles defined herein may be applied to other embodiments. Accordingly, the claims are not intended to be limited to the embodiments shown and described herein, but are to be accorded the full scope consistent with the claim language, and references to elements in the singular are intended to mean "one and only one," unless otherwise specified, but rather "one or more." All structural and functional equivalents to the elements of the various embodiments described throughout this disclosure that are known, or that later become known, to those skilled in the relevant art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be made available to the public.

Claims

1. 1. A bipolar battery stack that prevents air from being trapped during formation of the bipolar battery stack, comprising: a plurality of stacked battery cells; and an electrical and ionic insulating frame formed between each of the plurality of stacked battery cells; A bipolar stacked battery comprising:

2. 2. The bipolar stacked battery according to claim 1, wherein the insulating frame is arranged such that at least one end of each of the plurality of stacked battery cells is open so as not to completely enclose each of the plurality of stacked battery cells.

3. 2. The bipolar stacked battery according to claim 1, wherein the insulating frame is self-supporting between each of the plurality of stacked battery cells.

4. 2. The bipolar stacked battery according to claim 1, wherein the insulating frame is attached to only one current collector between adjacent stacked battery cells.

5. 2. The bipolar stacked battery according to claim 1, wherein the separators of each stacked battery cell and the inner end of the insulating frame are similar in shape.

6. 2. The bipolar stacked battery of claim 1, wherein the separators of each stacked battery cell and the inner ends of the insulating frame are similar in shape, but the remaining components of each stacked battery cell are dissimilar in shape.

7. 2. The bipolar stacked battery according to claim 1, wherein the area of ​​the separator is larger than the area of ​​the cathode layer and the area of ​​the anode layer of each stacked battery cell.

8. The area formed by the outer edge of the insulating frame (S ｆ，ｏｕｔｅｒ ) is the area of ​​the current collector (S ｃｃ ) or more, and for each stacked battery cell, 1≦(S ｆ，ｏｕｔｅｒ / S ｃｃ 2. The bipolar stacked battery according to claim 1, wherein

9. The area (S ｆ，ｉｎｎｅｒ ) and the separator area (S ｓｅｐ ) is 0.8≦(S ｆ，ｉｎｎｅｒ / S ｓｅｐ 2. The bipolar stacked battery according to claim 1, wherein the following relationship is satisfied: 1.)≦1.

43.

10. 2. The bipolar stacked battery according to claim 1, wherein a thickness (T) of each stacked battery cell of the plurality of stacked battery cells and a thickness (t) of the insulating frame satisfy 0.05≦(t / T)≦1.

22.

11. 11. The bipolar stacked battery according to claim 1, wherein a thickness (T) of each stacked battery cell of the plurality of stacked battery cells and a thickness (t) of the insulating frame satisfy 0.05≦(t / T)≦1.22, and the thickness (T) is equal to the sum of the thickness of the current collector of each stacked battery plus the thickness of the cathode layer plus the thickness of the separator plus the thickness of the anode layer plus the thickness of the current collector.

12. 1. A method of forming a bipolar battery stack that prevents air entrapment during formation of the bipolar battery stack, comprising: forming an electrically and ionically insulating frame between each of a plurality of stacked battery cells of the bipolar stacked battery.

13. 13. The method of claim 12, further comprising: arranging the insulating frame in each of the plurality of stacked battery cells such that at least one end of each of the plurality of stacked battery cells is open to open each of the plurality of stacked battery cells.

14. The method of claim 12 , including positioning the insulating frame so that the insulating frame is self-supporting between each of the plurality of stacked battery cells.

15. The method of claim 12 , including attaching the insulating frame to only one current collector between adjacent stacked battery cells.

16. The area formed by the outer edge of the insulating frame (S ｆ，ｏｕｔｅｒ ) is the area of ​​the current collector (S ｃｃ ) or more, and for each stacked battery cell, 1≦(S ｆ，ｏｕｔｅｒ / S ｃｃ 13. The method of claim 12, wherein

17. The area (S ｆ，ｉｎｎｅｒ ) and the separator area (S ｓｅｐ ) is 0.8≦(S ｆ，ｉｎｎｅｒ / S ｓｅｐ )≦1.

43.

18. 13. The method according to claim 12, wherein a thickness (T) of each stacked battery cell of the plurality of stacked battery cells and a thickness (t) of the insulating frame satisfy 0.05≦(t / T)≦1.

22.

19. 19. The method according to claim 12, wherein a thickness (T) of each stacked battery cell of the plurality of stacked battery cells and a thickness (t) of the insulating frame satisfy 0.05≦(t / T)≦1.22, and the thickness (T) is equal to the sum of the thickness of the current collector, the thickness of the cathode layer, the thickness of the separator, the thickness of the anode layer, and the thickness of the current collector of each stacked battery cell.

20. 1. A bipolar battery stack that prevents air from being trapped during formation of the bipolar battery stack, comprising: a plurality of stacked battery cells; and an electrical and ionic insulating frame formed between each of the plurality of stacked battery cells, wherein the insulating frame is arranged such that at least one end of each of the plurality of stacked battery cells is open so as not to completely enclose each of the plurality of stacked battery cells, wherein the separator of each stacked battery cell and the inner end of the insulating frame have similar shapes, and wherein an area (S ｆ，ｏｕｔｅｒ ) is the area of ​​the current collector (S ｃｃ ) or more, and for each stacked battery cell, 1≦(S ｆ，ｏｕｔｅｒ / S ｃｃ ) where the area (S ｆ，ｉｎｎｅｒ ) and the separator area (S ｓｅｐ ) is 0.8≦(S ｆ，ｉｎｎｅｒ / S ｓｅｐ )≦1.43, and wherein the thickness (T) of each stacked battery cell of the plurality of stacked battery cells and the thickness (t) of the insulating frame satisfy 0.05≦(t / T)≦1.

22. A bipolar stacked battery comprising:

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