Method for manufacturing bipolar battery

Abstract

A method of forming a bipolar battery can apply a cathode layer to a current collector, comprising: providing a cathode mixture; and feeding the cathode mixture through a plurality of cathode calender rolls. The method can apply an anode layer to a current collector, comprising: providing an anode mixture; and feeding the anode mixture through a plurality of anode calender rolls. The cathode mixture and the anode mixture are asymmetrically fed into a plurality of cathode calender rolls and a plurality of anode calender rolls.

Description

[0001] Related Applications

[0002] This patent application is related to a U.S. Provisional Application No. 63 / 601,156, titled "METHOD FOR MANUFACTURING A BIPOLAR BATTERY", filed on November 20, 2023, the entire content of which is incorporated herein by reference. This patent application claims the benefit of the above provisional application under 35 U.S.C. 119(e). Technical Field

[0003] The present disclosure generally relates to batteries, and more particularly, to a method for manufacturing a bipolar battery. Background Art

[0004] Electric vehicles (EVs) are becoming increasingly common in the market as an alternative to traditional internal combustion engine vehicles, mainly due to their environmental and advanced technological characteristics. The operation of an electric vehicle depends to a large extent on its battery system, which provides the necessary electrical energy for the motor.

[0005] Typically, in order to generate sufficient voltage to operate a high-torque motor in a vehicle, a large number of batteries need to be connected in series. However, this design has several inherent drawbacks. For example, one drawback is that the series stacking of batteries requires a large number of connection components. The connection components not only result in losses in energy density and power density due to volume loss, but they also introduce additional resistance, leading to a reduction in power density. In addition, the connection components tend to concentrate the current around the joint area, resulting in non-uniform temperature and current distribution in the battery. This ultimately leads to premature aging of the battery system.

[0006] To address these challenges, bipolar batteries have been developed. In these bipolar batteries, the positive and negative electrodes are arranged on both sides of a current collector, significantly reducing the need for connection components. However, current bipolar battery designs often lead to manufacturing challenges. Due to the asymmetry of the materials on the current collector, current methods may result in problems such as layer wrinkling or cracking. Current methods do not consider the asymmetry of the bipolar stack. For example, if the thicknesses of the anode and cathode are different, the current roller surface speeds used may result in layer wrinkling or cracking.

[0007] Therefore, there is a need to provide systems and methods that overcome the above problems. The systems and methods will provide a method for forming a bipolar battery that takes into account the asymmetry of the bipolar battery stack. The systems and methods will prevent layer wrinkling and cracking due to the asymmetry of the materials on the current collector. Summary of the Invention

[0008] The present invention content is provided to introduce some concepts in a simplified form, which will be further described in the detailed implementation manners of the present invention below. The present invention content is not intended to identify the key features of the claimed subject matter, nor is it intended to be used to help determine the scope of the claimed subject matter.

[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 may apply a cathode layer to a current collector, including: providing a cathode mixture; and feeding the cathode mixture through a plurality of cathode calendering rolls. The method may apply an anode layer to the current collector, including: providing an anode mixture; and feeding the anode mixture through a plurality of anode calendering rolls. The method may feed the cathode mixture and the anode mixture asymmetrically into the plurality of cathode calendering rolls and the plurality of anode calendering rolls.

[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 may apply a cathode layer to a current collector, including: providing a cathode mixture; and feeding the cathode mixture through a plurality of cathode calendering rolls, where the cathode calendering roll where the cathode mixture is initially fed is 0, and the cathode calendering 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 cathode calendering rolls c is equal. The method may apply an anode layer to the current collector, including: providing an anode mixture; and feeding the anode mixture through an odd number of anode calendering rolls, where the anode calendering roll where the anode mixture is initially fed is 0, and the anode calendering 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 calendering rolls a is equal. The angular velocity of each of the plurality of cathode calendering rolls and the angular velocity of each of the plurality of anode calendering rolls are proportional to the thickness of the cathode layer and the thickness of the anode layer applied to the current collector.

[0011] 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 apply a cathode layer to a current collector, including: providing a cathode mixture; and feeding the cathode mixture through a plurality of cathode calendering rolls, where the cathode calendering roll where the cathode mixture is initially fed is 0, and the cathode calendering 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 cathode calendering rolls c is equal. The method may apply an anode layer to the current collector, including: providing an anode mixture; and feeding the anode mixture through an odd number of anode calendering rolls, where the anode calendering roll where the anode mixture is initially fed is 0, and the anode calendering 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 calendering rolls aEqual. 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 may satisfy the following equation:

[0012] (0.8*k)*w c,2N+1 <w a,2N'+1 <(1.2*k)*w c,2N+1

[0013] k = (r c +t c,2N ) / (r a +t a,2N' )

[0014] where w c,N is the angular velocity of a specified cathode calender roll, N is a positive integer greater than or equal to 0, w a,N' is the angular velocity of a specified anode calender roll, N' is a positive integer greater than or equal to 0, r c is the radius of a single cathode calender roll, r a is the radius of a single anode calender roll, t c,2N is the gap between adjacent cathode calender rolls, t a,2N' is the gap between adjacent anode calender rolls. The method may apply a first separator layer to the cathode layer and a second separator layer to the anode layer, including: 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. 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 may satisfy the following equation:

[0015] (0.8*K s )*w sep,2M+1 <w sep,2M'+1 <(1.2*K s )*w sep,2M+1

[0016] K s = (r sep +t sep,2N ) / (r sep' +t sep,2M' ):where r sep is the radius of the separator calender roll in the first plurality of separator rolls, r sep' is the radius of the separator calender roll in the second plurality of separator rolls;

[0017] where w sep,N is the angular velocity of a specified separator calender roll in the first plurality of separator rolls, N is a positive integer greater than or equal to 0, w sep,N' is the angular velocity of a specified separator calender roll in the second plurality of calender rolls, N' is a positive integer greater than or equal to 0, rsep The radius of a single diaphragm calender roll that is one of the first plurality of diaphragm rolls or the second plurality of diaphragm rolls, t sep,2N The gap between adjacent diaphragm calender rolls in the first plurality of diaphragm rolls, t sep,2N' The gap between adjacent diaphragm calender rolls in the second plurality of calender rolls. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present application will be further described in detail with reference to the following drawings. These drawings are not intended to limit the scope of the present application, but rather to illustrate certain of its attributes. In all of the drawings, the same reference numerals will be used to refer to the same or similar parts.

[0019] Figure 1 A flowchart showing an exemplary method of forming a cathode mixture according to an embodiment of the present disclosure;

[0020] Figure 2 A flowchart showing an exemplary method of forming an anode mixture according to an embodiment of the present disclosure;

[0021] Figure 3 A flowchart showing an exemplary method of forming a separator mixture according to an embodiment of the present disclosure;

[0022] Figure 4 A block diagram showing an exemplary system for a bipolar stacked battery manufacturing method according to an embodiment of the present disclosure; and

[0023] Figure 5 A block diagram showing an exemplary system for a bipolar stacked battery manufacturing method according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0024] The following is intended to describe the 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. 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 achieved by different embodiments, which are also intended to be included within the spirit and scope of the present disclosure.

[0025] This patent application presents a bipolar battery manufacturing system and method applicable to electric vehicles. The system and method take into account the asymmetric characteristics of bipolar battery stacking and prevent layer wrinkling and cracking due to the asymmetry of the materials laminated on the current collector.

[0026] Currently, a bipolar stacked battery can be composed of 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 repeated sequence. These layers can be laminated together to form a stacked bipolar battery.

[0027] The cathode layer and the anode layer can be made by a series of calendering rollers. These layers can be laminated with the current collector. Generally, the calendering rollers can meet the following conditions:

[0028] w c,0 <w c,1 <w c,2 <w c,3 <…<w c,2N+1 (N: 0 or a positive integer)

[0029] w a,0 <w a,1 <w a,2 <w a,3 <…<w a,2N'+1 (N': 0 or a positive integer)

[0030] k = (r c +t c,2N ) / (r a +t a,2N' ): where r c and r a are the radii of the calendering rollers on the cathode side and the anode side respectively.

[0031] (0.8*k)*(w c,2N+1 ) < w a,2N'+1 < (1.2*k)*(w c,2N+1 )

[0032] Another set of calendering rollers can be present for manufacturing the separator layer on top of the cathode and the anode. These calendering rollers can meet the following conditions:

[0033] w sep,0 <w sep,1 <w sep,2 <w sep,3 <…<w sep,2M+1 (M: 0 or a positive integer)

[0034] w sep,0 <w sep,1 <w sep,2 <w sep,3 <…<w sep,2M'+1 (M': 0 or a positive integer)

[0035] K s = (r sep +t sep,2N ) / (r sep' +t sep,2M' ): where r sep and r sep' are the radii of the calendering rollers on the cathode side and the anode side respectively.

[0036] (0.8*K s )*(w sep,2M+1 ) < w sep,2M'+1 < (1.2*K s )*(w sep,2M+1 )。

[0037] The current method states that r c = r a , t c,2N = t a,2N' , w c = w a . This may be suitable for a monopolar stack with identical components (i.e., a stack of "cathode / current collector / cathode" or "anode / current collector / anode"). However, for a bipolar stack (cathode / current collector / anode), this setup generally does not work well because the stack is asymmetric.

[0038] Reference Figure 1 shows a method of forming a cathode mixture. In the Figure 1 method shown, a cathode active material (CAM), a binder, a conductive agent, and a solid electrolyte can be provided. Examples of CAM can include but are not limited to: layered lithium-containing oxide materials (such as LiCoO 2 , LiMnO 2 , LiNiO 2 , LiNi x Mn y Co 1-x-y O 2 , LiNi x Co y Al 1-x-y O 2 ), lithium-containing phosphates with an olivine structure (such as LiFePO 4 , LiFe x Mn 1-x PO 4 , LiMnPO 4 , LiFe x Co 1-x PO 4 , LiCoPO 4 ), lithium-containing oxide materials with a spinel structure (such as LiNi 0.5 Mn 1.5 O 4 , LiMn 2 O 4 ), layered structure oxides with excess lithium (such as Li 2 MnO 3 , Li 2 RuO 3 , Li 2 Ru xTi 1-x O 3 、Li 2 Ru x Sn 1-x O 3 、Li 2 Mn x Ti 1-x O 3 、Li 2 Mn x Sn 1-x O 3 )), layered lithium-containing sulfide materials (such as TiS 2 、MoS 2 、NbS 2 、TaS 2 ), sulfur, or lithium-containing sulfides with Chevrel structure (such as LiCu x MoS 1-z ). The surface of the CAM may be covered with a thin layer of material, i.e., a coating. Examples of the coating can include crystalline phases (such as Li 2 ZrO 3 、LiNbO 3 、LiPO 3 、Li 3 PO 4 、LiTi 2 (PO 4 ) 3 、LiZr(PO 4 ) 3 、ZrO 2 、Al 2 O 3 、EtOLi, MtOLi, LiOH, Li 2 CO 3 ), and / or amorphous phases (such as metal alkoxides, metal phosphates).

[0039] Binders can be used to interconnect the CAM and the conductive agent and to 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 with functional groups.

[0040] Conductive agents can be used to improve the electrical conductivity of conductive additives to ensure that the cathode formed from the cathode mixture has good charge and discharge performance. The conductive agent can function to collect microcurrents, thereby reducing the contact resistance of the electrode and accelerating the movement speed of electrons. The conductive agent can include, but is not limited to: various types of carbon, which can include acetylene black (AB), Ketjen black (KB), VGCF, carbon nanotubes, carbon nanohorns, and fullerenes.

[0041] A solid electrolyte can be provided to improve battery performance. Examples of electrolytes can include, but are not limited to: organic liquids, organic polymers, inorganic solids. Preferably, the electrolyte can be an inorganic solid because it has a higher transference number of lithium compared to liquids and a higher ionic conductivity compared to organic polymers. In addition, inorganic solids are generally rigid and do not exhibit fluidity, which may be preferred for forming a bipolar structure without ionic short circuits.

[0042] Some examples of electrolytes can include, but are not limited to, materials having the following compositions: 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).

[0043] Then, the CAM, binder, conductive agent, and solid electrolyte can be mixed. Different tools can be used in the mixing process. For example, the following processes / tools can be used during the mixing process:

[0044] High-shear mixer

[0045] Roller mixer

[0046] Twin-screw extruder.

[0047] The above-listed are examples and should not be considered restrictive. For example, in the case of using PTFE as an adhesive, low-temperature mixing can be considered. In particular, mixing below 19 °C can provide better PTFE particle uniformity without too much fibrillation because the phase change occurs at 19 °C. Above 19 °C, PTFE is prone to generating fibers under the action of a small amount of shear force. Below 19 °C, less fibrillation occurs and it can be dispersed by a stirrer under conditions lower than higher temperatures.

[0048] After the mixing process, a kneading process can be carried out. The kneading process can be completed using different tools. For example, the following kneading processes / tools that can be used are listed. Similarly, this list is given as an example and should not be considered restrictive. The kneading processes / tools can include:

[0049] Twin-screw extruder

[0050] Rubber kneader

[0051] Mochi machine

[0052] Automatic mortar.

[0053] The kneading process is optional and whether to use it depends on the materials used. For example, in the case of using PTFE as an adhesive, high-temperature mixing can be considered. In particular, mixing above 19 °C can provide better PTFE fiber uniformity because the phase change occurs at 19 °C. Above 19 °C, PTFE may generate fibers under the action of a small amount of shear force. As a result of kneading, a sheet of the cathode mixture can be obtained.

[0054] A powdering step can also be used. In the case of using the kneading process, a powdering process can be added to turn the sheet into powder. Examples of different powdering processes / tools are as follows:

[0055] High-speed grinder

[0056] Twin-screw extruder

[0057] Similarly, this list is given as an example and should not be considered restrictive.

[0058] Reference Figure 2 , shows a method of forming an anode mixture. In Figure 2 the method shown, an anode active material (AAM), an adhesive, a conductive agent, and a solid electrolyte can be provided. Examples of AAM include but are not limited to layered lithium-containing sulfide materials (such as TiS 2 , MoS 2 , NbS 2 , TaS 2 ), titanium-containing oxides (such as Li 4 Ti 5O 12 、Ti x Nb y O z 、LixTi 2 (PO 4 ) 3 )、 tungsten-containing oxides (such as Nb 16 W 5 O 55 、Nb 18 W 16 O 93 ), vanadium-containing oxides (such as LiVO 2 ), artificial carbon (or hard carbon), graphite, lithium metal alloys (such as Li x In, Li x Sn, Li x Si, Li x Ge, Li x Al) or metallic lithium.

[0059] Binders can be used to connect AAM and conductive agents to each other and to adhere the electrode material to the current collector. The binders used can be the same as those used in the above cathode process. However, different binders can also be used. Thus, 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 binders can be modified with functional groups.

[0060] Conductive agents can be used to improve the conductivity of the conductive additive to ensure that the anode formed from the anode mixture has good charge and discharge performance. The conductive agents can serve to collect microcurrents, thereby reducing the contact resistance of the electrode and accelerating the movement speed of electrons. The conductive agents can be the same as those used in the cathode mixture, but can also be different from those used in the cathode mixture. Thus, conductive agents can include but are not limited to: various types of carbon, which can include acetylene black (AB), Ketjen black (KB), VGCF, carbon nanotubes, carbon nanohorns, and fullerenes.

[0061] A solid electrolyte can be provided to improve battery performance. The electrolyte used can be the same as that used in the cathode mixture, but can also be different from that used in the cathode mixture. Examples of electrolytes used can include but are not limited to: organic liquids, organic polymers, inorganic solids. Preferably, the electrolyte can be an inorganic solid because it has a higher transference number of lithium compared to liquids and a higher ionic conductivity compared to organic polymers. In addition, inorganic solids are generally rigid and do not exhibit fluidity, which may be preferred for forming a bipolar structure without ionic short circuits.

[0062] Some examples of electrolytes may include, but are not limited to, materials having the following compositions: 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).

[0063] Then, the AAM, binder, conductive agent, and solid electrolyte can be mixed. Different tools can be used in the mixing process. The tools used in the mixing process can be the same as those used in the cathode mixture, but can also be different from those used in the cathode mixture. For example, the following processes / tools can be used in the mixing process:

[0064] High-shear mixer

[0065] Roller mixer

[0066] Twin-screw extruder.

[0067] The above are examples and should not be considered restrictive. For example, in the case of using PTFE as a binder, low-temperature mixing can be considered. Especially mixing below 19 °C can provide better PTFE particle uniformity without too much fibrillation because the phase change occurs at 19 °C. Above 19 °C, PTFE is prone to generating fibers under the action of a small amount of shear force. Below 19 °C, less fibrillation occurs and can be dispersed by a stirrer under conditions lower than higher temperatures.

[0068] After the mixing process, a kneading process can be carried out. The kneading process can be completed using different tools. The tools used in the kneading process can be the same as those used in the cathode mixture, but can also be different from those used in the cathode mixture. For example, the following kneading processes / tools can be used. Again, this list is given as an example and should not be considered restrictive. The kneading processes / tools can include:

[0069] Twin-screw extruder

[0070] Rubber kneader

[0071] Mochi machine

[0072] Automatic mortar.

[0073] The kneading process is optional and its use depends on the materials used. For example, in the case of using PTFE as an adhesive, high-temperature mixing can be considered. In particular, mixing above 19 °C can provide better PTFE fiber uniformity because the phase change occurs at 19 °C. Above 19 °C, PTFE may form fibers under the action of a small amount of shear force. As a result of kneading, a sheet of the cathode mixture can be obtained.

[0074] A powdering step can also be used. In the case of using the kneading process, a powdering process can be added to turn the sheet into powder. The tools used in the powdering process can be the same as those used in the cathode mixture, but can also be different from those used in the cathode mixture. Examples of different powdering processes / tools are as follows:

[0075] High-speed grinder

[0076] Twin-screw extruder

[0077] Similarly, this list is given as an example and should not be considered restrictive.

[0078] Reference Figure 3 , shows a method for forming a separator mixture. In Figure 3 In the method shown, an adhesive, a conductive agent, and a solid electrolyte can be provided. The adhesive can be used to adhere the separator material to the current collector. The adhesive used can be the same as that used in the above cathode process. However, a different adhesive can also be used. Therefore, examples of adhesives 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 adhesive can be modified with functional groups.

[0079] The conductive agent can be the same as the conductive agent used in the cathode mixture, but can also be different from the conductive agent used in the cathode mixture. Therefore, the conductive agent can include but is not limited to: various types of carbon, which can include acetylene black (AB), Ketjen black (KB), VGCF, carbon nanotubes, carbon nanohorns, and fullerenes.

[0080] The solid electrolyte used may be the same as that used in the cathode mixture, but it may also be different from the solid electrolyte used in the cathode mixture. Examples of electrolytes may include, but are not limited to: organic liquids, organic polymers, inorganic solids. Preferably, the electrolyte may be an inorganic solid because it has a higher transference number of lithium compared to liquids and a higher ionic conductivity compared to organic polymers. In addition, inorganic solids are generally rigid and do not exhibit fluidity, which may be preferred for forming a bipolar structure without ionic short circuits in the composition.

[0081] Some examples of electrolytes may include, but are not limited to, materials having the following compositions: 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).

[0082] Then, the binder, conductive agent, and solid electrolyte can be mixed. Different 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, but they may also be different from those used in the cathode mixture. For example, the following processes / tools can be used in the mixing process:

[0083] High-shear mixer

[0084] Roller mixer

[0085] Twin-screw extruder.

[0086] The above are listed as examples and should not be considered restrictive. For example, in the case of using PTFE as an adhesive, low-temperature mixing can be considered. In particular, mixing below 19 °C can provide better PTFE particle uniformity without generating too much fibrillation because the phase change occurs at 19 °C. Above 19 °C, PTFE may generate fibers under the action of a small amount of shear force. Below 19 °C, less fibrillation occurs and can be dispersed by a stirrer under conditions lower than higher temperatures.

[0087] After the mixing process, a kneading process can be carried out. The kneading process can be completed using different tools. The tools used in the kneading process can be the same as those used in the cathode mixture, but can also be different from those used in the cathode mixture. For example, the following kneading processes / tools can be used. Again, this list is given as an example and should not be considered restrictive. The kneading processes / tools can include:

[0088] Twin-screw extruder

[0089] Rubber kneader

[0090] Mochi machine

[0091] Automatic mortar.

[0092] The kneading process is optional and whether to use it depends on the materials used. For example, in the case of using PTFE as an adhesive, high-temperature mixing can be considered. In particular, mixing above 19 °C can provide better PTFE fiber uniformity because the phase change occurs at 19 °C. Above 19 °C, PTFE may generate fibers under the action of a small amount of shear force. As a result of kneading, sheets of the cathode mixture can be obtained.

[0093] A powdering step can also be used. In the case of using the kneading process, a powdering process can be added to turn the sheets into powder. The tools used in the powdering process can be the same as those used in the cathode mixture, but can also be different from those used in the cathode mixture. Examples of different powdering processes / tools are as follows:

[0094] High-speed grinder

[0095] Twin-screw extruder

[0096] Again, this list is given as an example and should not be considered restrictive.

[0097] See Figure 4 , the bipolar stack manufacturing method 1 includes the cathode layer sheet manufacturing method 2, the anode layer sheet manufacturing method 3, and the lamination of the current collector 10, the cathode layer 11, and the anode layer 12.

[0098] As Figure 4As shown, in the cathode laminate manufacturing method 2, the method can consist of a series of calendering rollers 5. According to one embodiment, there can always be an odd number of calendering rollers 5. The calendering rollers 5 can be numbered, with the calendering roller 5 at the cathode mixture feeding end numbered 0, and the calendering roller 5 at the end in contact with the current collector numbered 2N + 1, where N is a positive integer including 0.

[0099] The radius of each calendering roller 5 is defined as r c . The diameter of each calendering roller 5 can be from 10 mm to 1000 mm (5 mm < r c < 500 mm). According to one embodiment, each calendering roller 5 in the cathode laminate manufacturing method 2 can have the same radius r c .

[0100] The calendering rollers 5 can be made of different materials. According to one embodiment, each calendering roller 5 can be made of stainless steel, hardened steel (doped with Cr, W, Mo or V) or materials of a similar type. The surface of one or more calendering rollers 5 can be coated with diamond-like carbon (DLC) or chromium (Cr).

[0101] The angular velocity w of each calendering roller 5 c,k (0 ≤ k ≤ 2N + 1) can satisfy w c,0 < w c,1 < … < w c,2N+1 . This can apply a shear force to the binder to form fibers and stretch the powder into a sheet. The gap between adjacent calendering rollers 5 defined by m and m + 1 can be expressed as t c,m (0 ≤ m ≤ 2N). This gap can be from 0.0001 mm to 10 mm. The cathode mixture (powder or sheet) can be fed between the calendering rollers 5 numbered 0 and 1.

[0102] The temperature of each calendering roller 5 can be controlled. According to one embodiment, the temperature can be raised and can be from 15 °C to 250 °C. As described above, in the case of using PTFE as the binder, a temperature above 19 °C may be preferred because the phase transition temperature of PTFE is 19 °C. Above this temperature, PTFE exhibits more fibrillating behavior.

[0103] In the anode laminate manufacturing method 2, the method can consist of a series of calendering rollers 8. In this embodiment, there are an odd number of calendering rollers 8. The calendering rollers 8 can be numbered, with the calendering roller 8 at the cathode mixture feeding end numbered 0, and the calendering roller 8 at the end in contact with the current collector numbered 2N' + 1, where N' is a positive integer including 0.

[0104] The radius of each calendering roller 8 is defined as r a . The diameter of each calendering roller 8 can be from 10 mm to 1000 mm (5 mm < r a<500mm). According to one embodiment, all the calendering rolls 8 in the cathode laminate manufacturing method 2 can have the same radius r a .

[0105] The calendering rolls 8 can be made of different materials. According to the embodiment, the calendering rolls 8 can be made of stainless steel, hardened steel (doped with Cr, W, Mo or V), or materials of similar types. The surface of one or more calendering rolls 8 can be coated with diamond-like carbon (DLC) or chromium (Cr).

[0106] The angular velocity w of each calendering roll 8 c,k (0 ≤ k ≤ 2N'+1) can satisfy w a,0 < wa,1 <… < w a,2N'+1 . This can apply a shear force to the adhesive to form fibers and stretch the powder into a sheet. The gap between adjacent calendering rolls 8 defined by m and m + 1 can be expressed as t a,m (0 ≤ m ≤ 2N'). This gap can be from 0.0001 mm to 10 mm. The anode mixture (powder or sheet) can be fed between the calendering rolls 8 numbered 0 and 8.

[0107] The temperature of each calendering roll 8 can be controlled. According to one embodiment, the temperature of the calendering roll 8 can be increased. This temperature can be from 15°C to 250°C. It is particularly preferred to be higher than 19°C because the phase transition temperature of PTFE is 19°C. Above this temperature, PTFE exhibits more fibrillating behavior.

[0108] During the lamination process, the cathode laminate 6 and the anode laminate 9 can be laminated onto the current collector 10. The current collector 10 can pass between the calendering roll 5 numbered 2N + 1 in the cathode laminate manufacturing method 2 and the calendering roll 8 numbered 2N'+1 in the anode laminate manufacturing method 3. The current collector 10 can move from the bottom to the top in the vertical direction.

[0109] During the lamination process, the speeds of the calendering roll 5 and the calendering roll 8 should satisfy the following relationship:

[0110] (0.8*k)*w c,2N+1 < w a,2N'+1 <(1.2*k)*w c,2N+1

[0111] k = (r c + t c,2N ) / (r a + t a,2N' ).

[0112] Reference Figure 5, the diaphragm manufacturing method and the lamination method 13, 13' can be seen. It should be noted that it is important to avoid cross - contamination of the diaphragm by the CAM, AAM, and the conductive agent. Therefore, the diaphragm manufacturing method and the lamination method 13, 13' should be above the bipolar stacking method 1. A partition wall 17 can also be inserted between the diaphragm manufacturing method lamination method 13, 13' and the bipolar stacking method 1.

[0113] Figure 5 For the shown diaphragm manufacturing method and lamination method 13, 13', a series of calender rolls 15, 15' can be used on each side of the diaphragm manufacturing method and lamination method 13, 13'. In this embodiment, there are an odd number of calender rolls 15, 15' on each side. The calender rolls 15, 15' can be numbered. The number of the calender roll 15 at the cathode mixture feeding end is 0, and the number of the calender roll 15 at the end in contact with the current collector is 2M + 1, where M is a positive integer including 0. Similarly, for numbering the calender roll 15', the number of the calender roll 15' at the anode mixture feeding end is 0, and the number of the calender roll 15' at the end in contact with the current collector is 2M + 1, where M is a positive integer including 0.

[0114] The radius of each calender roll 15, 15' is defined as r sep . The gap between adjacent calender rolls 15, 15' can be defined as m and m + 1, denoted as t sep,m (0 ≤ m ≤ 2N). This gap can be from 0.0001 mm to 10 mm.

[0115] The diaphragm mixture (powder or sheet) 14, 14' can be fed between the calender rolls 15, 15' numbered 0 and 1 on each side of the diaphragm manufacturing method and lamination method 13, 13'. The angular velocity w c,k (0 ≤ k ≤ 2M + 1) of each calender roll 15, 15' can satisfy w sep,0 < w sep,1 <…< w sep,2N+1 . This can apply a shear force to the adhesive to form fibers and stretch the powder into a sheet.

[0116] During Figure 5 , during the lamination process, the formed diaphragm sheets 16, 16' can be laminated to the bipolar stacking layers, namely the cathode layer 11 and the anode layer 12 respectively. The calender rolls 15, 15' should satisfy the following relationship:

[0117] The diaphragm sheets 16, 16' are laminated onto the bipolar stacking layers.

[0118] w sep,0 < w sep,1 < w sep,2 < w sep,3 <…< w sep,2M+1

[0119] w sep,0 <w sep,1 <w sep,2 <w sep,3 <…<w sep,2M ' +1

[0120] (0.8*K s )*w sep,2M+1 <w sep,2M'+1 <(1.2*K s )*w sep,2M+1

[0121] K s =(r sep +t sep,2N ) / (r sep' +t sep,2M' ):where r sep and rsep' are the radii of the calendering rollers on the cathode side and the anode side, respectively.

[0122] The reference numerals of the elements in the drawings are as follows:

[0123] 1. Bipolar layer manufacturing system

[0124] 2. Cathode calendering roller

[0125] 3. Anode calendering roller

[0126] 4. Cathode mixture (powder or sheet)

[0127] 5. Cathode calendering roller

[0128] 6. Cathode layer sheet

[0129] 7. Anode mixture (powder or sheet)

[0130] 8. Anode calendering roller

[0131] 9. Anode layer sheet

[0132] 10. Current collector

[0133] 11. Cathode layer

[0134] 12. Anode layer

[0135] 13, 13' Diaphragm manufacturing method and lamination method

[0136] 14, 14' Diaphragm mixture (powder or sheet)

[0137] 15, 15' Diaphragm calendering roller

[0138] 16, 16' Diaphragm layer sheet (powder or sheet)

[0139] 17. Dividing wall.

[0140] The foregoing description is intended to enable any person skilled in the relevant art to implement the various embodiments described herein. Various modifications to these embodiments will be apparent to those skilled in the relevant art, and the general principles defined herein can be applied to other embodiments. Therefore, the claims are not intended to be limited to the embodiments shown and described herein, but rather to conform to the full scope consistent with the language of the claims, where the elements in the singular form are not intended to mean "one and only one" unless specifically stated, but rather "one or more". All structures and functions equivalent to the elements of the various embodiments described herein, whether known or later known to those of ordinary skill in the relevant art, are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public.

Claims

1. A method of forming a bipolar battery, comprising: Applying the cathode layer to the current collector comprises: providing a cathode mixture; and feeding the cathode mixture through a plurality of cathode calendering rollers; Applying an anode layer to the current collector comprises: providing an anode mixture; and feeding the anode mixture through a plurality of anode calendering rollers; The cathode mixture and the anode mixture are asymmetrically fed into the plurality of cathode calendering rollers and the plurality of anode calendering rollers.

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

3. The method according to claim 1, comprising: A gap is formed between the last cathode calendering roll and the last anode calendering roll, and the current collector is fed at the gap to apply the cathode layer and the anode layer, wherein the angular velocity at the gap formed between the last cathode calendering roll and the last anode calendering roll is asymmetric.

4. The method according to claim 1, wherein the angular velocity of each of the plurality of cathode calendering rollers and the angular velocity of each of the plurality of anode calendering rollers are proportional to the gap formed between a current cathode calendering roller and a directly adjacent cathode calendering roller among the plurality of cathode calendering rollers and the gap formed between a current anode calendering roller and a directly adjacent anode calendering roller among the plurality of anode calendering rollers.

5. The method according to claim 1, wherein the radius r of each of the plurality of cathode calendering rollers is c Equal and within 5mm <r c <500mm.

6. The method according to claim 1, wherein the radius r of each of the plurality of anode calendering rollers is a Equal and within 5mm <r a <500mm.

7. The method according to claim 1, comprising: The temperature of each cathode calendering roller is controlled, wherein the temperature of each cathode calendering roller ranges from 15°C to 250°C.

8. The method according to claim 1, comprising: The temperature of each anode calendering roller is controlled, wherein the temperature of each anode calendering roller ranges from 15°C to 250°C.

9. The method according to claim 2, wherein the angular velocity of each of the plurality of cathode calendering rollers and the angular velocity of each of the plurality of anode calendering rollers 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' ) where w c,N is the angular velocity of the specified cathode calender roller, N is a positive integer greater than or equal to 0, and w a,N' is the angular velocity of the specified anode calendering roller, N' is a positive integer greater than or equal to 0, r c is the radius of a single cathode calendering roller, r a is the radius of a single anode calendering roller, t c,2N is the gap between adjacent cathode calendering rolls, t a,2N' It is the gap between adjacent anode calendering rolls.

10. The method according to claim 1, comprising: Applying a first separator layer to the cathode layer and applying a second separator layer to the anode layer comprises: providing a cathode separator mixture; providing an anode diaphragm mixture; feeding the cathode separator mixture through a first plurality of separator calendaring rolls; and feeding the anode separator mixture through a second plurality of separator calendaring rolls; The angular velocity of each of the first plurality of separator calendering rollers and the angular velocity of each of the second plurality of separator calendering rollers are proportional to the thickness of the cathode separator layer and the thickness of the anode separator layer applied to the current collector.

11. The method of claim 10, wherein the angular velocity of each of the first plurality of membrane rollers and the angular velocity of each of the second plurality of membrane calendaring rollers 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' ):where r sep is the radius of the membrane calendering roller in the first plurality of membrane rollers, r sep' is the radius of a membrane calendering roller in the second plurality of membrane rollers; where w sep,N is the angular velocity of a specified membrane calendering roller in the first plurality of membrane rollers, N is a positive integer greater than or equal to 0, and w sep,N' is the angular velocity of the designated membrane calendering roll in the second plurality of calendering rolls, N' is a positive integer greater than or equal to 0, r sep is the radius of a single membrane calendering roll of one of the first plurality of membrane rolls or the second plurality of membrane rolls, t sep,2N is the gap between adjacent membrane calendering rolls in the first plurality of membrane rolls, t sep,2N' is the gap between adjacent membrane calendering rolls in the second plurality of calendering rolls.

12. A method of forming a bipolar battery, comprising: Applying the cathode layer to the current collector comprises: providing a cathode mixture; and Feeding the cathode mixture through a plurality of cathode calendering rollers, wherein the cathode calendering roller to which the cathode mixture is initially fed is 0, and the cathode calendering roller in contact with the current collector is 2N+1, wherein N is a positive integer greater than or equal to 0, wherein the radius r of each of the plurality of cathode calendering rollers is c equal; Applying an anode layer to the current collector comprises: providing an anode mixture; and The anode mixture is fed through an odd number of anode calendering rollers, wherein the anode calendering roller to which the anode mixture is initially fed is 0, and the anode calendering roller in contact with the current collector is 2N'+1, wherein N' is a positive integer greater than or equal to 0, and the radius r of each of the plurality of anode calendering rollers is a equal; The angular velocity of each of the plurality of cathode calendering rollers and the angular velocity of each of the plurality of anode calendering rollers are proportional to the thickness of the cathode layer and the thickness of the anode layer applied to the current collector.

13. The method according to claim 12, wherein the angular velocity of each of the plurality of cathode calendering rollers satisfies w c,0 <w c,1 <… <w c,2N+1 .

14. The method according to claim 12, wherein the angular velocity of each of the plurality of cathode calendering rollers satisfies w a,0 <w a,1 <… <w a,2N'+1 .

15. The method according to claim 12, wherein the angular velocity of each of the plurality of cathode calendering rollers and the angular velocity of each of the plurality of anode calendering rollers 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' ) where w c,N is the angular velocity of the specified cathode calender roller, N is a positive integer greater than or equal to 0, and w a,N' is the angular velocity of the specified anode calendering roller, N' is a positive integer greater than or equal to 0, r c is the radius of a single cathode calendering roller, r a is the radius of a single anode calendering roller, t c,2N is the gap between adjacent cathode calendering rolls, t a,2N' It is the gap between adjacent anode calendering rolls.

16. The method according to claim 12, comprising: Applying a first separator layer to the cathode layer and applying a second separator layer to the anode layer comprises: providing a cathode separator mixture; providing an anode diaphragm mixture; feeding the cathode separator mixture through a first plurality of separator calendaring rolls; and feeding the anode separator mixture through a second plurality of separator calendaring rolls; The angular velocity of each of the first plurality of separator calendering rollers and the angular velocity of each of the second plurality of separator calendering rollers are proportional to the thickness of the cathode separator layer and the thickness of the anode separator layer applied to the current collector.

17. The method of claim 16, wherein the angular velocity of each of the first plurality of membrane rollers and the angular velocity of each of the second plurality of membrane calendaring rollers 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' ):where r sep is the radius of the membrane calendering roller in the first plurality of membrane rollers, r sep' is the radius of a membrane calendering roller in the second plurality of membrane rollers; where w sep,N is the angular velocity of a specified membrane roller in the first plurality of membrane rollers, N is a positive integer greater than or equal to 0, and w sep,N' is the angular velocity of the designated membrane calendering roll in the second plurality of calendering rolls, N' is a positive integer greater than or equal to 0, r sep is the radius of a single membrane calendering roll of one of the first plurality of membrane rolls or the second plurality of membrane rolls, t sep,2N is the gap between adjacent membrane calendering rolls in the first plurality of membrane rolls, t sep,2N' is the gap between adjacent membrane calendering rolls in the second plurality of calendering rolls.

18. The method according to claim 12, comprising: The temperature of each cathode calendering roller is controlled, wherein the temperature of each cathode calendering roller ranges from 15°C to 250°C.

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

20. A method of forming a bipolar battery, comprising: Applying the cathode layer to the current collector comprises: providing a cathode mixture; and Feeding the cathode mixture through a plurality of cathode calendering rollers, wherein the cathode calendering roller to which the cathode mixture is initially fed is 0, and the cathode calendering roller in contact with the current collector is 2N+1, wherein N is a positive integer greater than or equal to 0, wherein the radius r of each of the plurality of cathode calendering rollers is c equal; Applying an anode layer to the current collector comprises: providing an anode mixture; and The anode mixture is fed through an odd number of anode calendering rollers, wherein the anode calendering roller to which the anode mixture is initially fed is 0, and the anode calendering roller in contact with the current collector is 2N'+1, wherein N' is a positive integer greater than or equal to 0, and the radius r of each of the plurality of anode calendering rollers is a equal; The angular velocity of each of the plurality of cathode calendering rollers and the angular velocity of each of the plurality of anode calendering rollers 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' ) where w c,N is the angular velocity of the specified cathode calender roller, N is a positive integer greater than or equal to 0, and w a,N' is the angular velocity of the specified anode calendering roller, N' is a positive integer greater than or equal to 0, r c is the radius of a single cathode calendering roller, r a is the radius of a single anode calendering roller, t c,2N is the gap between adjacent cathode calendering rolls, t a,2N' is the gap between adjacent anode calendering rolls; Applying a first separator layer to the cathode layer and applying a second separator layer to the anode layer comprises: providing a cathode separator mixture; providing an anode diaphragm mixture; feeding the cathode separator mixture through a first plurality of separator calendaring rolls; and feeding the anode separator mixture through a second plurality of separator calendaring rolls; Wherein the angular velocity of each of the first plurality of membrane rollers and the angular velocity of each of the second plurality of membrane calendaring rollers 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' ):where r sep is the radius of the membrane calendering roller in the first plurality of membrane rollers, r sep' is the radius of a membrane calendering roller in the second plurality of membrane rollers; where w sep,N is the angular velocity of a specified membrane calendering roller in the first plurality of membrane rollers, N is a positive integer greater than or equal to 0, and w sep,N' is the angular velocity of a designated diaphragm roll in the second plurality of calender rolls, N' is a positive integer greater than or equal to 0, r sep is the radius of a single membrane calendering roll of one of the first plurality of membrane rolls or the second plurality of membrane rolls, t sep,2N is the gap between adjacent membrane calendering rolls in the first plurality of membrane rolls, t sep,2N' is the gap between adjacent membrane calendering rolls in the second plurality of calendering rolls.

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