Method for manufacturing bipolar battery

Abstract

To provide a method for manufacturing a bipolar battery which prevents a layer from being creased and damaged by a character of asymmetry of a material on a current collector.SOLUTION: A method for forming a bipolar battery may apply a cathode layer to a current collector, comprising: providing a cathode mixture; and feeding the cathode mixture through a plurality of cathode calendar rolls. The method may apply an anode layer to the current collector, comprising: providing an anode mixture; and feeding the anode mixture through a plurality of anode calendar rolls. The cathode mixture and the anode mixture are fed into the plurality of cathode calendar rolls and the plurality of anode calendar rolls asymmetrically.SELECTED DRAWING: None

Description

Technical Field

[0001] Related Applications This patent application is related to U.S. Provisional Application No. 63 / 601,156, entitled "Method for Manufacturing a Bipolar Battery," filed on November 20, 2023, the entire disclosure of which is incorporated herein by reference. This patent application claims the benefit under 35 U.S.C. § 119(e) of the aforementioned provisional application.

[0002] Technical Field This disclosure generally relates to batteries, and more specifically, to methods for manufacturing bipolar batteries.

Background Art

[0003] Background of the Invention Electric vehicles (EVs) are becoming increasingly popular in the market as an alternative to conventional internal combustion engine vehicles, mainly due to their environmentally friendly nature and advanced technological features. The operation of an electric vehicle highly depends on its battery system that provides the electrical energy necessary to power the motor.

[0004] Conventionally, in order to generate a voltage sufficient to operate a high-torque motor in a vehicle, a large number of batteries are connected in series. However, this design has several inherent drawbacks. One drawback is that, for example, a significant number of junction components are required for the stacking of the series of batteries. Junction components not only contribute to the loss of energy density and power density due to volume loss but also introduce additional resistance, leading to a decrease in power density. Furthermore, junction components tend to concentrate current around the junction area, resulting in a non-uniform temperature and current distribution across the entire battery. This can ultimately contribute to the premature degradation of the battery system.

[0005] To address these issues, bipolar batteries have been developed. In these bipolar batteries, the positive and negative electrodes are arranged on both sides of the current collector, significantly reducing the need for joining components. However, the current design of bipolar batteries often poses manufacturing challenges. The current methodology can lead to problems such as layer wrinkles or breakage due to the asymmetric nature of the materials on the current collector. The current methodology does not consider the asymmetry of the bipolar stack. For example, if the anode and cathode have different thicknesses, the currently used speed of the roll surface can cause layer wrinkles or breakage.

[0006] Therefore, it is desirable to provide a system and method that overcome the above. The system and method will provide a method for forming a bipolar battery that takes into account the asymmetric nature of the bipolar battery stack. The system and method will prevent layer wrinkles and breakage due to the asymmetric nature of the materials on the current collector. SUMMARY OF THE INVENTION

[0007] Summary of the Invention This summary is provided to introduce a selected simplification of the concepts 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.

[0008] According to an embodiment of the present disclosure, a method for forming a bipolar battery is provided. The method for forming a bipolar battery may include applying a cathode layer to a current collector and may include: providing a cathode mixture; and supplying the cathode mixture through a plurality of cathode calendar rolls. The method may include applying an anode layer to the current collector and may include: providing an anode mixture; and supplying the anode mixture through a plurality of anode calendar rolls. The method may supply the cathode mixture and the anode mixture asymmetrically to the plurality of cathode calendar rolls and the plurality of anode calendar rolls.

[0009] According to an embodiment of the present disclosure, a method for forming a bipolar battery is provided. The method for forming a bipolar battery includes applying a cathode layer to a current collector and may include: providing a cathode mixture; and supplying the cathode mixture through a plurality of cathode calendar rolls, wherein the cathode calendar roll to which the cathode mixture is first supplied is 0, and the cathode calendar roll in contact with the current collector is 2N + 1, where N is a positive integer greater than or equal to 0, and where the radius r of each of the plurality of cathode calendar rolls c is equal. The method includes applying an anode layer to a current collector and may include: providing an anode mixture; and supplying the anode mixture through an odd number of anode calendar rolls, wherein the anode calendar roll to which the anode mixture is first supplied is 0, and the anode calendar roll in contact with the current collector is 2N'+1, where N' is a positive integer greater than or equal to 0, and the radius r of each of the plurality of anode calendar rolls a is equal. The angular velocity of each of the plurality of cathode calendar rolls and the angular velocity of each of the plurality of anode calendar rolls are proportional to the thickness of the cathode layer and the thickness of the anode layer applied to the current collector.

[0010] According to an embodiment of the present disclosure, a method for forming a bipolar battery is provided. The method for forming a bipolar battery includes applying a cathode layer to a current collector and may include: providing a cathode mixture; and supplying the cathode mixture through a plurality of cathode calendar rolls, wherein the cathode calendar roll to which the cathode mixture is first supplied is 0, and the cathode calendar roll in contact with the current collector is 2N + 1, where N is a positive integer greater than or equal to 0, and where the radius r of each of the plurality of cathode calendar rolls care equal. The method may include applying an anode layer to a current collector and: providing an anode mixture; and feeding the anode mixture through an odd number of anode calendar rolls, where the anode calendar roll to which the anode mixture is first fed is 0, and the anode calendar roll in contact with the current collector is 2N'+1, where N' is a positive integer greater than or equal to 0, and the radius r of each of the plurality of anode calendar rolls a are equal. The angular velocity of each of the plurality of cathode calendar rolls and the angular velocity of each of the plurality of anode calendar rolls may satisfy the following equation: (0.8*k)*w c,2N+1 <w a,2N’+1 <(1.2*k)*w c,2N+1 k=(r c +t c,2N ) / (r a +t a,2N’ ) wherein, w c,N is the angular velocity of a specified cathode calendar roll, N is a positive integer greater than or equal to 0, w a,N’ is the angular velocity of a specified anode calendar roll, N' is a positive integer greater than or equal to 0, r c is the radius of an individual cathode calendar roll, r a is the radius of an individual anode calendar roll, t c,2N is the gap between adjacent cathode calendar rolls, t a,2N’ is the gap between adjacent anode calendar rolls. The method may include applying a first separator layer to the cathode layer, applying a second separator layer to the anode layer, and may include: providing a cathode separator mixture; providing an anode separator mixture; feeding the cathode separator mixture through a first plurality of separator calendar rolls; and feeding the anode separator mixture through a second plurality of separator calendar rolls. The angular velocity of each of the first plurality of separator rolls and the angular velocity of each of the second plurality of separator calendar rolls may satisfy the following equation: (0.8*K s)*w sep,2M+1 <w sep,2M’+1 <(1.2*K s )*w sep,2M+1 K s =(r sep +t sep,2N ) / (r sep’ +t sep,2M’ ): wherein, r sep is the radius of the separator calendar roll of the first plurality of separator rolls, and r sep’ is the radius of the separator calendar roll of the second plurality of separator rolls; wherein, w sep,N is the angular velocity of the designated separator calendar roll of the first plurality of separator rolls, N is a positive integer of 0 or more, and w sep,N’ is the angular velocity of the designated separator calendar roll of the second plurality of calendar rolls, N' is a positive integer of 0 or more, and r sep is the radius of an individual separator calendar roll of either the first plurality of separator rolls or the second plurality of separator rolls, and t sep,2N is the gap between adjacent separator calendar rolls of the first plurality of separator rolls, and t sep,2N’ is the gap between adjacent separator calendar rolls of the second plurality of calendar rolls.

[0011] Brief Description of the Drawings This application is further described in detail with reference to the following drawings. These drawings are not intended to limit the scope of the application, but rather are intended to illustrate its specific attributes. Throughout the drawings, the same reference numerals are used to refer to the same or similar parts.

Brief Description of the Drawings

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Figure 1

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Figure 2

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Figure 3

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Figure 4

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Figure 5

[0017] **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 form in which the present disclosure may be constructed and / or utilized. This description sets forth the functions and sequences of steps for constructing and operating the present disclosure. However, it should be understood that the same or equivalent functions and sequences may be achieved by different embodiments that are intended to be within the spirit and scope of the present disclosure.

[0018] This patent application proposes a system and method for manufacturing a bipolar battery suitable for an electric vehicle. The system and method take into account the asymmetric nature of the bipolar battery stack and prevent wrinkles and breakage of the layers due to the asymmetric nature of the materials laminated on the current collector.

[0019] At present, a laminated bipolar battery can be composed by repeating a current collector, a cathode layer, a separator, an anode layer, another current collector, a second cathode layer, a second separator, a second anode layer, etc. in this order. These layers can be laminated together to form a laminated bipolar battery.

[0020] The cathode layer and the anode layer can be manufactured by a series of calendar rolls. The said layers can be laminated with the current collector. Generally, the calendar rolls can meet the following conditions. w c,0 <w c,1 <w c,2 <w c,3 <…<w c,2N+1 (N: 0 or a positive integer) w a,0 <w a,1 <w a,2 <w a,3 <…<w a,2N’+1 (N’: 0 or a positive integer) k = (r c + t c,2N ) / (r a + t a,2N’ ): where r c 、r a are the radii of the cathode-side and anode-side calendar rolls, respectively. (0.8 * k) * (w c,2N+1 ) < w a,2N’+1 < (1.2 * k) * (w c,2N+1 ) There may be another set of calendar rolls that can be used to manufacture the separator layer on the upper surfaces of the cathode and anode. Those calendar rolls can meet the following conditions. w sep,0 <w sep,1 <w sep,2 <w sep,3 <…<w sep,2M+1 (M: 0 or a positive integer) w sep,0 <w sep,1 <w sep,2 <w sep,3 <…<w sep,2M’+1 (M’: 0 or a positive integer) K s = (r sep+t sep,2N ) / (r sep’ +t sep,2M’ ): where r sep and r sep’ are the radii of the calendar rolls on the cathode side and anode side, respectively. (0.8*K s )*(w sep,2M+1 ) < w sep,2M’+1 < (1.2*K s )*(w sep,2M+1 )

[0021] The current methodology assumes r c = r a , t c,2N = t a,2N’ and w c = w a and functions for a mono-polar laminate having the same components (i.e., a laminate of "cathode / current collector / cathode" or "anode / current collector / anode"). However, in the case of a bipolar laminate (cathode / current collector / anode), since the laminate is not symmetric, this setting generally does not work well.

[0022] Referring to Figure 1, a process for forming a cathode mixture can be shown. In the process shown in Figure 1, a cathode active material (CAM), a binder, a conductive agent, and a solid electrolyte can be provided. Examples of CAM include, but are not limited to, layered lithium-containing oxide materials (LiCoO2, LiMnO2, LiNiO2, LiNi x Mn y Co 1-x-y O2, LiNi x Co y Al 1-x-y O2, etc.), lithium-containing phosphates having an olivine structure (LiFePO4, LiFe x Mn 1-x PO4, LiMnPO4, LiFe x Co 1-x PO4, LiCoPO4, etc.), lithium-containing oxide materials having a spinel structure (LiNi 0.5 Mn 1.5O4, LiMn2O4, etc.), lithium-excess layered structure 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 having a Chevrel structure (LiCu x MoS 1-z etc.). The surface of the CAM can be coated by a thin layer of material, i.e., a coating. Examples of coatings can include crystalline phases (Li2ZrO3, LiNbO3, LiPO3, Li3PO4, LiTi2(PO4)3, LiZr(PO4)3, ZrO2, Al2O3, EtOLi, MtOLi, LiOH, Li2CO3, etc.) and / or amorphous phases (metal alkoxides, metal phosphates, etc.).

[0023] Binders can be used to interconnect the CAM and the conductive agent and adhere the electrode material to the current collector. Examples of binders that can be included in the cathode mixture include, but are not limited to, butadiene rubber (BR), butyl rubber (IIR), acrylate butadiene rubber (ABR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE). The side chains of the binder can be modified by functional groups.

[0024] The conductive agent can be used to improve the electrical conductivity of the conductive additive so that the cathode formed using the cathode mixture has good charge and discharge performance. The conductive agent can have the effect of collecting minute currents so as to reduce the contact resistance of the electrode and the accelerated electron transfer rate. The conductive agent can include various types of carbon including, but not limited to, acetylene black (AB), ketjen black (KB), VGCF, carbon nanotubes, carbon nanohorns, and fullerenes.

[0025] Solid electrolytes can be provided to improve battery performance. Examples of electrolytes can include, but are not limited to, organic liquids, organic polymers, and inorganic solids. Preferably, the electrolyte can be an inorganic solid due to a higher transference number of lithium compared to liquids and higher ionic conductivity than organic polymers. Further, inorganic solids are usually hard and non-fluid and can be preferable for constituting a bipolar structure without ion short-circuit.

[0026] Some examples of electrolytes can include, but are not limited to, materials having compositions of Li-P-O-N, Li-Si-O, Li-B-Si-O, Li-B-O, Li-C-B-O, Li-Al-Si-O, Li-Ti-Al-P-O, Li-Zr-Al-P-O, Li-La-Zr-O, Li-La-Ta-Zr-O, Li-La-Nb-Zr-O, Li-M-S (where M is B, Al, Si, P, Zn, Ge, Zr, Sn or a combination thereof), Li-M'-S-O (where M' is B, Al, Si, P, Zn, Ge, Zr, Sn or a combination thereof), Li-P-S-X (where X is F, Cl, Br or a combination thereof), Li-P-S-O-X' (where X' is F, Cl, Br or a combination thereof), Li-B-H, Li-B-N-H, Li-B-H-O, Li-B-N-H-O, Li-M''-X'' (where 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 (where M'' is In, Zr, Sc, Ga, Nb, Ta or a combination thereof; X'' is F, Cl, Br or a combination thereof).

[0027] Next, the CAM, binder, conductive agent, and solid electrolyte can be mixed. Various tools can be used in the mixing process. For example, the processes / tools listed below can be used during the mixing process: High-shear mixer Tumbler mixer Twin-screw extruder

[0028] The above list is given by way of example and should not be seen as limiting. For example, when using PTFE as a binder, low-temperature mixing can be considered. In particular, mixing below 19 °C can provide better uniformity of PTFE particles without much fibrillation, since the phase transition occurs at 19 °C. Above 19 °C, PTFE tends to form fibrils with a small amount of shear force. Below 19 °C, fibrillation is less likely to occur and can be dispersed by a mixer at a temperature lower than that of higher temperatures.

[0029] After the mixing process, a kneading process can be carried out. The kneading process can be carried out with various tools. For example, the following are kneading processes / tools that can be used. Again, the list is given by way of example and should not be seen as limiting. The kneading process / tools can include: Twin-screw extruder Rubber kneader Molding press Automatic mortar

[0030] The kneading process is optional and its use can depend on the materials used. For example, when using PTFE as a binder, high-temperature mixing can be considered. In particular, mixing above 19 °C can provide better uniformity of PTFE fibrils, since the phase transition occurs at 19 °C. Above 19 °C, PTFE can form fibrils with a small amount of shear force. As a result of kneading, flakes of the cathode mixture can be obtained.

[0031] A pulverization process can also be used. When a kneading process is used, a pulverization process can be added to turn the flakes into powder. Examples of various pulverization processes / tools are as follows: High-speed grinder Twin-screw extruder Again, the list is given by way of example and should not be seen as limiting.

[0032] Referring to FIG. 2, a process for forming an anode mixture can be shown. In the process shown in FIG. 2, an anode active material (AAM), a binder, a conductive agent, and a solid electrolyte can be provided. Examples of AAM include layered lithium-containing sulfide materials (such as TiS2, MoS2, NbS2, TaS2, etc.), titanium-containing oxides (such as Li4Ti5O 12 、Ti x Nb y O z 、Li x Ti2(PO4)3, etc.), tungsten-containing oxides (such as Nb 16 W5O 55 、Nb 18 W 16 O 93 、etc.), vanadium-containing oxides (such as LiVO2, etc.), artificial carbon (or hard carbon), graphite, Li metal alloys (such as Li x In, Li x Sn, Li x Si, Li x Ge, Li x Al, etc.), or metallic lithium, but are not limited thereto.

[0033] The binder can be used to interconnect the AAM and the conductive agent and to adhere the electrode material to the current collector. The binder used can be the same as that used in the above cathode process. However, different binders can also be used. Therefore, examples of binders that can be included in the anode mixture can include, but are not limited to, butadiene rubber (BR), butyl rubber (IIR), acrylate butadiene rubber (ABR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE). The side chains of the binder can be modified by functional groups.

[0034] The conductive agent can be used to improve the electrical conductivity of the conductive additive so as to ensure that the anode formed of the anode mixture has good charge and discharge performance. The conductive agent can have the effect of collecting minute currents so as to reduce the contact resistance of the electrode and the moving speed of accelerated electrons. The conductive agent may be the same as that used in the cathode mixture or may be different from that of the cathode mixture. Therefore, the conductive agent can include various types of carbon including, but not limited to, acetylene black (AB), ketjen black (KB), VGCF, carbon nanotubes, carbon nanohorns, and fullerenes.

[0035] The solid electrolyte can be provided to improve battery performance. The electrolyte used may be the same as that used in the cathode mixture or may be different from that of the cathode mixture. Examples of the electrolyte used can include, but are not limited to, organic liquids, organic polymers, and inorganic solids. Preferably, the electrolyte can be an inorganic solid due to its higher lithium transport rate compared to liquids and higher ionic conductivity than organic polymers. Furthermore, the inorganic solid is usually hard and does not show fluidity and can be preferable for constituting a bipolar structure without ionic short circuit.

[0036] Some examples of electrolytes can include, but are not limited to, materials having compositions of Li-P-O-N, Li-Si-O, Li-B-Si-O, Li-B-O, Li-C-B-O, Li-Al-Si-O, Li-Ti-Al-P-O, Li-Zr-Al-P-O, Li-La-Zr-O, Li-La-Ta-Zr-O, Li-La-Nb-Zr-O, Li-M-S (where M is B, Al, Si, P, Zn, Ge, Zr, Sn, or a combination thereof), Li-M'-S-O (where M' is B, Al, Si, P, Zn, Ge, Zr, Sn, or a combination thereof), Li-P-S-X (where X is F, Cl, Br, or a combination thereof), Li-P-S-O-X' (where X' is F, Cl, Br, or a combination thereof), Li-B-H, Li-B-N-H, Li-B-H-O, Li-B-N-H-O, Li-M''-X'' (where 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 (where M'' is In, Zr, Sc, Ga, Nb, Ta, or a combination thereof; X'' is F, Cl, Br, or a combination thereof).

[0037] Next, the AAM, binder, conductive agent, and solid electrolyte can be mixed. Various tools can be used in the mixing process. The tools used in the mixing process may be the same as those used in the cathode mixture or different from those of the cathode mixture. For example, the following processes / tools listed below can be used during the mixing process: High shear mixer Tumbler mixer Twin screw extruder

[0038] The above list is provided by way of example and should not be viewed as limiting. For example, when using PTFE as a binder, low-temperature mixing can be considered. In particular, mixing below 19 °C can provide better uniformity of PTFE particles without much fibrillation because the phase transition occurs at 19 °C. Above 19 °C, PTFE tends to form fibrils with a small amount of shear force. Below 19 °C, fibrillation is less likely to occur and can be dispersed by a mixer at a temperature lower than that of high temperature.

[0039] After the mixing process, a kneading process can be carried out. The kneading process can be carried out with various tools. The tools used in the kneading process may be the same as those used in the cathode mixture, or may be different from those of the cathode mixture. For example, the following listed ones are kneading processes / tools that can be used. Here too, the list is provided by way of example and should not be viewed as limiting. The kneading process / tools can include: Twin-screw extruder Rubber kneader Mochi press Automatic mortar

[0040] The kneading process is optional and can depend on the materials used. For example, when using PTFE as a binder, high-temperature mixing can be considered. In particular, mixing above 19 °C can provide better uniformity of PTFE fibrils because the phase transition occurs at 19 °C. Above 19 °C, PTFE can form fibrils with a small amount of shear force. As a result of kneading, flakes of the cathode mixture can be obtained.

[0041] A pulverization process can also be used. When a kneading process is used, a pulverization process can be added to make the flakes into powder. The tools used in the pulverization process may be the same as those used in the cathode mixture, or may be different from those of the cathode mixture. Examples of various pulverization processes / tools are as follows: High-speed grinder Twin-screw extruder Here too, the list is given by way of example and should not be seen as restrictive.

[0042] Referring to FIG. 3, a process for forming a separator mixture can be shown. In the process shown in FIG. 3, a binder, a conductive agent, and a solid electrolyte can be provided. The binder can be used to adhere the separator material to the current collector. The binder used may be the same as that used in the above-described cathode process. However, different binders can also be used. Thus, examples of binders that can be included in the separator mixture can include, but are not limited to, butadiene rubber (BR), butyl rubber (IIR), acrylate butadiene rubber (ABR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE). The side chains of the binder can be modified by functional groups.

[0043] The conductive agent may be the same as that used in the cathode mixture, or it may be different from that of the cathode mixture. Thus, the conductive agent can include various types of carbon including, but not limited to, acetylene black (AB), ketjen black (KB), VGCF, carbon nanotubes, carbon nanohorns, and fullerenes.

[0044] The solid electrolyte used may be the same as that used in the cathode mixture, or it may be different from that of the cathode mixture. Examples of electrolytes can include, but are not limited to, organic liquids, organic polymers, and inorganic solids. Preferably, the electrolyte can be an inorganic solid due to its higher lithium transport rate compared to liquids and higher ionic conductivity than organic polymers. Furthermore, the inorganic solid is usually hard and does not show fluidity, and can be preferable for forming a bipolar structure without ion short-circuit.

[0045] Some examples of electrolytes can include, but are not limited to, materials having compositions of Li-P-O-N, Li-Si-O, Li-B-Si-O, Li-B-O, Li-C-B-O, Li-Al-Si-O, Li-Ti-Al-P-O, Li-Zr-Al-P-O, Li-La-Zr-O, Li-La-Ta-Zr-O, Li-La-Nb-Zr-O, Li-M-S (where M is B, Al, Si, P, Zn, Ge, Zr, Sn, or a combination thereof), Li-M'-S-O (where M' is B, Al, Si, P, Zn, Ge, Zr, Sn, or a combination thereof), Li-P-S-X (where X is F, Cl, Br, or a combination thereof), Li-P-S-O-X' (where X' is F, Cl, Br, or a combination thereof), Li-B-H, Li-B-N-H, Li-B-H-O, Li-B-N-H-O, Li-M''-X'' (where 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 (where M'' is In, Zr, Sc, Ga, Nb, Ta, or a combination thereof; X'' is F, Cl, Br, or a combination thereof).

[0046] Next, a binder, a conductive agent, and a solid electrolyte can be mixed. Various tools can be used in the mixing process. The tools used in the mixing process may be the same as those used in the cathode mixture or different from those of the cathode mixture. For example, the processes / tools listed below can be used during the mixing process: High-shear mixer Tumbler mixer Twin-screw extruder

[0047] The above list is given by way of example and should not be seen as limiting. For example, when using PTFE as a binder, low-temperature mixing can be considered. In particular, mixing below 19 °C can provide better uniformity of PTFE particles without much fibrillation, since the phase transition occurs at 19 °C. Above 19 °C, PTFE can form fibrils with a small amount of shear force. Below 19 °C, fibrillation is less likely to occur and it can be dispersed by a mixer at a temperature lower than that of high temperature.

[0048] After the mixing process, a kneading process can be carried out. The kneading process can be carried out with various tools. The tools used in the kneading process may be the same as those used in the cathode mixture, but may also be different from those of the cathode mixture. For example, the following are kneading processes / tools that can be used. Again, the list is given by way of example and should not be seen as limiting. The kneading process / tools can include: Twin-screw extruder Rubber kneader Mochi press Automatic mortar

[0049] The kneading process is optional and may depend on the materials used. For example, when using PTFE as a binder, high-temperature mixing can be considered. In particular, mixing above 19 °C can provide better uniformity of PTFE fibrils, since the phase transition occurs at 19 °C. Above 19 °C, PTFE can form fibrils with a small amount of shear force. As a result of kneading, flakes of the cathode mixture can be obtained.

[0050] A pulverization process can also be used. When a kneading process is used, a pulverization process can be added to make the flakes into powder. The tools used in the pulverization process may be the same as those used in the cathode mixture, but may also be different from those of the cathode mixture. Examples of various pulverization processes / tools are as follows: High-speed grinder Twin-screw extruder Here too, the lists are given by way of example and should not be seen as limiting.

[0051] Referring to FIG. 4, the bipolar lamination manufacturing process 1 comprises a cathode layer sheet manufacturing process 2, an anode layer sheet manufacturing process 3, and laminating a current collector 10, a cathode layer 11, and an anode layer 12.

[0052] As can be seen in FIG. 4, in the cathode layer sheet manufacturing process 2, the process can consist of a series of calender rolls 5. According to an embodiment, there may always be an odd number of calender rolls 5. The calender rolls 5 can be numbered, and the number of the calender roll 5 at the end where the cathode mixture is supplied is 0, and the number of the calender roll 5 at the end in contact with the current collector is 2N + 1, where N is a positive integer including 0.

[0053] Each calender roll 5 may have a radius that can be defined as r c The diameter of each calender roll 5 can be 10 mm to 1,000 mm (5 mm < r c < 500 mm). According to an embodiment, each of the calender rolls 5 in the cathode layer sheet manufacturing process 2 may have the same radius r c having.

[0054] The calender rolls 5 may be made of various materials. According to an embodiment, each calender roll 5 may be made of stainless steel, hardened steel (doped with Cr, W, Mo, or V), or a similar type of material. One or more surfaces of the calender roll 5 may be coated with diamond-like carbon (DLC) or chromium (Cr).

[0055] The angular velocity w c,k (0 <= k <= 2N + 1) of each calender roll 5 is w c,0 < w c,1 < … < w c,2N+1can be satisfied. This allows for applying a shearing force to the binder to form fibrils and stretching the powder into a sheet shape. The gap between adjacent calendar rolls 5 defined by m and m + 1 can be t c,m (0 <= m <= 2N). The gap can be in the range between 0.0001 mm and 10 mm. The cathode mixture (powder or flakes) can be supplied between the calendar rolls 5 numbered 0 and 1.

[0056] The temperature of each calendar roll 5 can be controlled. According to one embodiment, the temperature can be raised and can be in the range between 15°C and 250°C. As described above, when using PTFE as the binder, since PTFE has a phase transition temperature at 19°C, a temperature above 19°C can be preferable. When exceeding this temperature, PTFE exhibits more fibrillation behavior.

[0057] In the anode layer sheet manufacturing process 2, the process may consist of a series of calendar rolls 8. In this embodiment, there are odd-numbered calendar rolls 8. The calendar rolls 8 can be numbered, and the calendar roll 8 at the end where the cathode mixture is supplied is 0, and the calendar roll 8 at the end in contact with the current collector is numbered 2N' + 1, where N is a positive integer including 0.

[0058] Each calendar roll 8 can have a radius defined as r a Each calendar roll 8 can have a diameter: 10 mm to 1,000 mm (5 mm < r a < 500 mm). According to one embodiment, all the calendar rolls 8 in the cathode layer sheet manufacturing process 2 can have the same radius r a can have.

[0059] The calendar roll 8 may be made of various materials. According to one embodiment, the calendar roll 8 may be made of stainless steel, hardened steel (doped with Cr, W, Mo, or V), or a similar type of material. One or more surfaces of the calendar roll 8 may be coated with diamond-like carbon (DLC) or chromium (Cr).

[0060] The angular velocity w of each calendar roll 8 c,k (0 <= k <= 2N’ + 1) is such that w a,0 < w a,1 < … < w a,2N’+1 may be satisfied. This may apply a shear force to the binder to form fibrils and stretch the powder into a sheet. The gap between adjacent calendar rolls 8 defined as calendar rolls m and m + 1 is t a,m (0 <= m <= 2N’) and may be represented. The gap may range between 0.0001 mm and 10 mm. The anode mixture (powder or flakes) may be supplied between the calendar roll 8 labeled 0 and the calendar roll 8 labeled 1.

[0061] The temperature of each calendar roll 8 may be controlled. According to one embodiment, the temperature of the calendar roll 8 can be increased. The temperature range may be between 15°C and 250°C. Since PTFE has a phase transition temperature at 19°C, temperatures above 19°C are particularly preferred. Above this temperature, PTFE exhibits more fibrillation behavior.

[0062] During the lamination process, the cathode layer sheet 6 and the anode layer sheet 9 may be laminated on the current collector 10. The current collector 10 may pass between the (2N + 1)-th calendar roll 5 from the cathode layer manufacturing process 2 and the (2N’ + 1)-th calendar roll 8 from the anode layer manufacturing process 3. The current collector 10 may move vertically from bottom to top.

[0063] During the lamination process, the speeds of the calendar rolls 5 and 8 should satisfy the following relationship. (0.8 * k) * w c,2N+1<w a,2N’+1 <(1.2*k)*w c,2N+1 k=(r c +t c,2N ) / (r a +t a,2N’ )

[0064] Referring to FIG. 5, the processes of separator manufacturing and lamination processes 13, 13' can be seen. It should be noted that it is important to avoid cross-contamination of the separator by CAM, AAM, and the conductive agent. Therefore, the separator manufacturing and lamination processes 13, 13' should be above the bipolar lamination process 1. Also, a partition wall 17 may be inserted between the separator manufacturing and lamination processes 13, 13' and the bipolar lamination process 1.

[0065] For the separator manufacturing and lamination processes 13, 13' shown in FIG. 5, a series of calendar rolls 15, 15' can be used on each side of the separator manufacturing and lamination processes 13, 13'. In this embodiment, there are an odd number of calendar rolls 15, 15' on each side. The calendar rolls 15, 15' can be numbered. The number of the calendar roll 15 at the end where the cathode mixture is supplied is 0, and the number of the calendar roll 15 at the end in contact with the current collector is 2M + 1, where M is a positive integer including 0. Similarly, the calendar roll 15' can be numbered. The number of the calendar roll 15' at the end where the anode mixture is supplied is 0, and the number of the calendar roll 15' at the end in contact with the current collector is 2M + 1, where M is a positive integer including 0.

[0066] Each calendar roll 15, 15' may have a radius defined as r sep The gap between adjacent calendar rolls 15, 15' that can be defined as m and m + 1 is t sep,m (0 <= m <= 2N). The gap can be in the range between 0.0001 mm and 10 mm.

[0067] Separator mixtures (powders or flakes) 14, 14' can be fed between calender rolls 15, 15' numbered 0 and roll 1 on each side of the separator manufacturing and lamination processes 13, 13'. The angular velocity w of each calender roll 15, 15' c,k (0 <= k <= 2M + 1) is such that w sep,0 < w sep,1 < … < w sep,2N+1 can be satisfied. This can apply shear force to the binder to form fibrils and stretch the powder into a sheet shape.

[0068] In FIG. 5, during the lamination process, the separator sheets 16, 16' formed can be laminated to the bipolar lamination layers, namely the cathode layer 11 and the anode layer 12 respectively. The calender rolls 15, 15' should satisfy the following relationship. The separator sheets 16, 16' are laminated to the bipolar lamination layers. w sep,0 < w sep,1 < w sep,2 < w sep,3 < … < w sep,2M+1 w sep,0 < w sep,1 < w sep,2 < w sep,3 < … < w sep,2M’+1 (0.8 * K s ) * w sep,2M+1 < w sep,2M’+1 < (1.2 * K s ) * w sep,2M+1 K s = (r sep + t sep,2N ) / (r sep’ + t sep,2M’ ): where r sep and r sep’ are the radii of the calender rolls on the cathode side and the anode side respectively.

Explanation of symbols

[0069] The elements in the figure can be labeled as follows: 1 Bipolar layer manufacturing system 2 Cathode Calendar Roll 3 Anode Calendar Roll 4 Cathode Mixture (Powder or Flakes) 5 Cathode Calendar Roll 6 Cathode Layer Sheet 7 Anode Mixture (Powder or Flakes) 8 Anode Calendar Roll 9 Anode Layer Sheet 10 Current Collector 11 Cathode Layer 12 Anode Layer 13, 13' Separator Manufacturing and Laminating Process 14, 14' Separator Mixture (Powder or Flakes) 15, 15' Separator Calendar Roll 16, 16' Separator Layer Sheet (Powder or Flakes) 17 Partition Wall

[0070] The foregoing description is provided to enable any person skilled in the relevant art to practice the various embodiments described herein. Various changes 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 should be accorded the full scope consistent with the claim language, and reference to a singular element is not intended to mean "one and only one" unless specifically stated otherwise, 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 later become known to those skilled in the relevant art are expressly incorporated herein by reference and are intended to be included in the claims. Further, what is disclosed herein is not intended to be dedicated to the public.

Claims

1. 1. A method for forming a bipolar battery, comprising: applying a cathode layer to a current collector, the layer comprising: providing a cathode mixture; and feeding the cathode mixture through a plurality of cathode calender rolls; applying an anode layer to said current collector, comprising: providing an anode mix; and feeding the anode mix through a plurality of anode calender rolls; wherein the cathode mixture and the anode mixture are asymmetrically fed to the plurality of cathode calender rolls and the plurality of anode calender rolls; The method includes:

2. 2. The method of claim 1, wherein the angular velocity of each of the plurality of cathode calender rolls and the angular velocity of each of the plurality of anode calender rolls are proportional to the thickness of the cathode layer and the anode layer applied to the current collector.

3. 2. The method of claim 1, further comprising forming a gap between a last cathode calender roll and a last anode calender roll, wherein the current collector is fed to apply the cathode layer and the anode layer, and wherein an angular velocity in the gap formed between the last cathode calender roll and the last anode calender roll is asymmetric.

4. 2. The method of claim 1, wherein the angular velocity of each of the plurality of cathode calender rolls and the angular velocity of each of the plurality of anode calender rolls are proportional to the gap formed between a current cathode calender roll of the plurality of cathode calender rolls and an immediately adjacent cathode calender roll of the plurality of anode calender rolls and a gap formed between a current anode calender roll of the plurality of anode calender rolls and an immediately adjacent anode calender roll of the plurality of anode calender rolls.

5. The radius r of each of the plurality of cathode calender rolls ｃ are equal, and 5 mm < r ｃ 2. The method of claim 1, wherein the distance is in the range of <500 mm.

6. The radius r of each of the plurality of anode calender rolls ａ are equal, and 5 mm < r ａ 2. The method of claim 1, wherein the distance is in the range of <500 mm.

7. 10. The method of claim 1, comprising controlling the temperature of each cathode calender roll, wherein the temperature of each cathode calender roll ranges between 15°C and 250°C.

8. 10. The method of claim 1, comprising controlling the temperature of each anode calender roll, wherein the temperature of each anode calender roll ranges between 15°C and 250°C.

9. The angular velocity of each of the plurality of cathode calender rolls and the angular velocity of each of the plurality of anode calenders satisfy the following formula: (0.8*k)*w ｃ，２Ｎ＋１ <w ａ，２Ｎ’＋１ <(1.2*k)*w ｃ，２Ｎ＋１ k=(r ｃ +t ｃ，２Ｎ ) / (r ａ +t ａ，２Ｎ’ ) During the ceremony, w ｃ，Ｎ is the angular velocity of the designated cathode calender roll, N is a positive integer equal to or greater than 0, and w ａ，Ｎ’ is the angular velocity of the designated anode calender roll, N′ is a positive integer equal to or greater than 0, and r ｃ is the radius of each cathode calendar roll, and r ａ is the radius of each anode calender roll, and t ｃ，２Ｎ is the gap between adjacent cathode calender rolls, and t ａ，２Ｎ’ The method of claim 2 , wherein A is the gap between adjacent anode calender rolls.

10. applying a first separator layer to the cathode layer and a second separator layer to the anode layer, comprising: providing a cathode separator mixture; providing an anode separator mixture; feeding the cathode separator mixture through a first plurality of separator calender rolls; and feeding the anode separator mixture through a second plurality of separator calender rolls; wherein the angular velocity of each of the first plurality of separator calender rolls and the angular velocity of each of the second plurality of separator calender rolls are proportional to the thickness of the cathode separator layer and the thickness of the anode separator layer applied to the current collector. The method according to any one of claims 1 to 9, comprising:

11. The angular velocity of each of the first plurality of separator rolls and the angular velocity of each of the second plurality of separator calender rolls satisfy the following formula: (0.8*K ｓ )*w ｓｅｐ，２Ｍ＋１ <w ｓｅｐ，２Ｍ’＋１ <(1.2*K ｓ )*w ｓｅｐ，２Ｍ＋１ K ｓ = (r ｓｅｐ +t ｓｅｐ，２Ｎ ) / (r ｓｅｐ’ +t ｓｅｐ，２Ｍ’ ): where r ｓｅｐ is the radius of the separator calender roll of the first plurality of separator rolls, r ｓｅｐ’ is the radius of the separator calender roll of the second plurality of separator rolls; During the ceremony, w ｓｅｐ，Ｎ is the angular velocity of a designated separator calender roll of the first plurality of separator rolls, N is a positive integer equal to or greater than 0, and w ｓｅｐ，Ｎ’ is the angular velocity of a designated separator calender roll of the second plurality of calender rolls, N′ is a positive integer equal to or greater than 0, and r ｓｅｐ is the radius of an individual separator calender roll of one of the first plurality of separator rolls or the second plurality of separator rolls, and t ｓｅｐ，２Ｎ is the gap between adjacent separator calender rolls of the first plurality of separator rolls, and t ｓｅｐ，２Ｎ’ 11. The method of claim 10, wherein: is the gap between adjacent separator calender rolls of the second plurality of calender rolls.

12. 1. A method for forming a bipolar battery, comprising: applying a cathode layer to a current collector, the layer comprising: providing a cathode mixture; and Supplying the cathode mixture through a plurality of cathode calender rolls, where the cathode calender roll to which the cathode mixture is first supplied is 0, and the cathode calender roll in contact with the current collector is 2N+1, where N is a positive integer greater than or equal to 0, and where a radius r of each of the plurality of cathode calender rolls is 1. ｃ are equal to applying an anode layer to said current collector, comprising: providing an anode mix; and supplying the anode mixture through an odd number of anode calender rolls, where the anode calender roll to which the anode mixture is first supplied is 0, and the anode calender roll in contact with the current collector is 2N′+1, where N′ is a positive integer greater than or equal to 0, and a radius r of each of the plurality of anode calender rolls is 1. ａ are equal to wherein the angular velocity of each of the plurality of cathode calender rolls and the angular velocity of each of the plurality of anode calender rolls are proportional to the thickness of the cathode layer and the thickness of the anode layer applied to the current collector. The method includes:

13. The angular velocity of each of the plurality of cathode calender rolls is w ｃ，０ <w ｃ，１ <...<w ｃ，２Ｎ＋１ The method according to claim 12, wherein

14. The angular velocity of each of the plurality of anode calender rolls is w ａ，０ <w ａ，１ <...<w ａ，２Ｎ’＋１ The method according to claim 12, wherein

15. The angular velocity of each of the plurality of cathode calender rolls and the angular velocity of each of the plurality of anode calender rolls satisfy the following formula: (0.8*k)*w ｃ，２Ｎ＋１ <w ａ，２Ｎ’＋１ <(1.2*k)*w ｃ，２Ｎ＋１ k=(r ｃ +t ｃ，２Ｎ ) / (r ａ +t ａ，２Ｎ’ ) During the ceremony, w ｃ，Ｎ is the angular velocity of the designated cathode calender roll, N is a positive integer equal to or greater than 0, and w ａ，Ｎ’ is the angular velocity of the designated anode calender roll, N′ is a positive integer equal to or greater than 0, and r ｃ is the radius of each cathode calendar roll, and r ａ is the radius of each anode calender roll, and t ｃ，２Ｎ is the gap between adjacent cathode calender rolls, and t ａ，２Ｎ’ The method of claim 12 , wherein A is the gap between adjacent anode calender rolls.

16. applying a first separator layer to the cathode layer and a second separator layer to the anode layer, comprising: providing a cathode separator mixture; providing an anode separator mixture; feeding the cathode separator mixture through a first plurality of separator calender rolls; and feeding the anode separator mixture through a second plurality of separator calender rolls; wherein the angular velocity of each of the first plurality of separator calender rolls and the angular velocity of each of the second plurality of separator calender rolls are proportional to the thickness of the cathode separator layer and the thickness of the anode separator layer applied to the current collector. The method according to any one of claims 12 to 15, comprising:

17. The angular velocity of each of the first plurality of separator rolls and the angular velocity of each of the second plurality of separator calender rolls satisfy the following formula: (0.8*K ｓ )*w ｓｅｐ，２Ｍ＋１ <w ｓｅｐ，２Ｍ’＋１ <(1.2*K ｓ )*w ｓｅｐ，２Ｍ＋１ K ｓ = (r ｓｅｐ +t ｓｅｐ，２Ｎ ) / (r ｓｅｐ +t ｓｅｐ，２Ｍ’ ): in the formula, r ｓｅｐ is the radius of the separator calender roll of the first plurality of separator rolls, r ｓｅｐ’ is the radius of the separator calender roll of the second plurality of separator rolls; During the ceremony, w ｓｅｐ，Ｎ is the angular velocity of a designated separator calender roll of the first plurality of separator rolls, N is a positive integer equal to or greater than 0, and w ｓｅｐ，Ｎ’ is the angular velocity of a designated separator calender roll of the second plurality of calender rolls, N′ is a positive integer equal to or greater than 0, and r ｓｅｐ is the radius of an individual separator calender roll of one of the first plurality of separator rolls or the second plurality of separator rolls, and t ｓｅｐ，２Ｎ is the gap between adjacent separator calender rolls of the first plurality of separator rolls, and t ｓｅｐ，２Ｎ’ 17. The method of claim 16, wherein: is the gap between adjacent separator calender rolls of the second plurality of calender rolls.

18. 13. The method of claim 12, comprising controlling the temperature of each cathode calender roll, wherein the temperature of each cathode calender roll ranges between 15°C and 250°C.

19. The method according to claim 12, wherein the surface of each cathode calender roll is coated with diamond-like carbon (DLC) or chromium (Cr).

20. 1. A method for forming a bipolar battery, comprising: applying a cathode layer to a current collector, the layer comprising: providing a cathode mixture; and Supplying the cathode mixture through a plurality of cathode calender rolls, where the cathode calender roll to which the cathode mixture is first supplied is 0, and the cathode calender roll in contact with the current collector is 2N+1, where N is a positive integer greater than or equal to 0, and where a radius r of each of the plurality of cathode calender rolls is 1. ｃ are equal to applying an anode layer to said current collector, comprising: providing an anode mix; and supplying the anode mixture through an odd number of anode calender rolls, where the anode calender roll to which the anode mixture is first supplied is 0, and the anode calender roll in contact with the current collector is 2N′+1, where N′ is a positive integer greater than or equal to 0, and a radius r of each of the plurality of anode calender rolls is 1. ａ are equal to Wherein, the angular velocity of each of the plurality of cathode calender rolls and the angular velocity of each of the plurality of anode calender rolls satisfy the following formula: (0.8*k)*w ｃ，２Ｎ＋１ <w ａ，２Ｎ’＋１ <(1.2*k)*w ｃ，２Ｎ＋１ k=(r ｃ +t ｃ，２Ｎ ) / (r ａ +t ａ，２Ｎ’ ) During the ceremony, w ｃ，Ｎ is the angular velocity of the designated cathode calender roll, N is a positive integer equal to or greater than 0, and w ａ，Ｎ’ is the angular velocity of the designated anode calender roll, N′ is a positive integer equal to or greater than 0, and r ｃ is the radius of each cathode calendar roll, and r ａ is the radius of each anode calender roll, and t ｃ，２Ｎ is the gap between adjacent cathode calender rolls, and t ａ，２Ｎ’ is the gap between adjacent anode calendar rolls; applying a first separator layer to the cathode layer and a second separator layer to the anode layer, comprising: providing a cathode separator mixture; providing an anode separator mixture; feeding the cathode separator mixture through a first plurality of separator calender rolls; and feeding the anode separator mixture through a second plurality of separator calender rolls; wherein the angular velocity of each of the first plurality of separator rolls and the angular velocity of each of the second plurality of separator calender rolls satisfy the following formula: (0.8*K ｓ )*w ｓｅｐ，２Ｍ＋１ <w ｓｅｐ，２Ｍ’＋１ <(1.2*K ｓ )*w ｓｅｐ，２Ｍ＋１ K ｓ = (r ｓｅｐ +t ｓｅｐ，２Ｎ ) / (r ｓｅｐ’ +t ｓｅｐ，２Ｍ’ ): where r ｓｅｐ is the radius of the separator calender roll of the first plurality of separator rolls, r ｓｅｐ’ is the radius of the separator calender roll of the second plurality of separator rolls; During the ceremony, w ｓｅｐ，Ｎ is the angular velocity of a designated separator calender roll of the first plurality of separator rolls, N is a positive integer equal to or greater than 0, and w ｓｅｐ，Ｎ’ is the angular velocity of a designated separator calender roll of the second plurality of calender rolls, N′ is a positive integer equal to or greater than 0, and r ｓｅｐ is the radius of an individual separator calender roll of one of the first plurality of separator rolls or the second plurality of separator rolls, and t ｓｅｐ，２Ｎ is the gap between adjacent separator calender rolls of the first plurality of separator rolls, and t ｓｅｐ，２Ｎ’ is the gap between adjacent separator calender rolls of the second plurality of calender rolls; The method includes:

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