Roll-to-roll, step-by-step extrusion process for manufacturing self-supporting active material layers for battery electrodes using semi-dry powders

Abstract

The present invention relates to a roll-to-roll, stepwise extrusion process for manufacturing self-supporting active material layers for battery electrodes using semi-dry powders. A method for manufacturing a cathode electrode of a battery cell includes providing a dry powder mixture including an active material, a conductive additive, and a binder to a first extruder; mixing the active material, the conductive additive, and the binder in a first extruder; fibrillating the adhesive portion in a first extruder; supplying the mixture from the first extruder to a first inlet of a second extruder; supplying the solvent to a second inlet of the second extruder; mixing the active material, the conductive additive, the binder and the solvent in a second extruder; fibrillating the adhesive in a second extruder; and forming an active material layer using an extrusion die disposed at an outlet of the second extruder.

Description

Technical Field

[0001] This disclosure relates to battery packs, and more particularly to a method for manufacturing active material layers and / or electrodes for battery packs using semi-dry powder. Background Technology

[0002] The information provided in this section is intended to provide a general overview of the background of this disclosure. The work of the currently named inventors described in this section, and the aspects of the specification that may not have been otherwise identified as prior art at the time of filing, are not expressly or impliedly acknowledged as prior art to this disclosure.

[0003] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid electric vehicles, and / or fuel cell vehicles, include one or more motors and battery pack systems, said battery pack system including one or more battery cells, battery modules, and / or battery packs. A power control system is used to control the charging and / or discharging of the battery pack system during charging and / or driving.

[0004] The battery pack includes a cathode electrode, an anode electrode, and a separator. The cathode electrode includes a layer of cathode active material (including cathode active material) disposed on a cathode current collector. The anode electrode includes a layer of anode active material (including anode active material) disposed on an anode current collector. Summary of the Invention

[0005] A method for manufacturing a cathode for a battery pack includes supplying a dry powder mixture comprising an active material, a conductive additive, and a binder to a first extruder; mixing the active material, the conductive additive, and the binder in the first extruder; partially fibrillating the binder in the first extruder; supplying the mixture from the first extruder to a first inlet of a second extruder; supplying a solvent to a second inlet of the second extruder; mixing the active material, the conductive additive, the binder, and the solvent in the second extruder; fibrillating the binder in the second extruder; and forming an active material layer using an extrusion die disposed at the outlet of the second extruder.

[0006] Among other features, the first temperature of the first extruder is between 19°C and 70°C, and the second temperature of the second extruder is greater than 70°C.

[0007] Among other characteristics, the adhesive is selected from polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), ethylene tetrafluoroethylene (ETFE), polyethylene (PE), and combinations thereof. The particle size of the adhesive ranges from 1 μm to 1000 μm. The particle size of the adhesive ranges from 1 μm to 50 μm.

[0008] Among other characteristics, the solvent is selected from alcohols, esters, and combinations thereof. The solvent accounts for 5% to 20% by weight of the mixture. Partial fibrillation of the adhesive in the first extruder includes fibrillating 10% to 40% of the adhesive. Fibrillation of the adhesive in the second extruder includes fibrillating more than 90% of the adhesive.

[0009] Among other features, the second temperature of the mixture in the second extruder is below 150°C. The method includes outputting an active material layer onto a support membrane. The method includes outputting the active material layer as a self-supporting membrane. The method includes pressing and heating the active material layer and laminating the active material layer onto a current collector.

[0010] A method for manufacturing a cathode electrode for a battery pack includes providing a dry powder mixture comprising a cathode active material, a conductive additive, and a binder to a first inlet of an extruder; mixing the cathode active material, the conductive additive, and the binder in a first section of the extruder; partially fibrillating the binder in the first section of the extruder; supplying a first solvent to a second section of the extruder; further partially fibrillating the binder in the second section of the extruder; supplying a second solvent to a third section of the extruder; fibrillating the binder in the third section of the extruder; and forming an active material layer using a slotted die disposed at the outlet of the third section of the extruder.

[0011] Among other characteristics, the adhesive is selected from polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), ethylene tetrafluoroethylene (ETFE), polyethylene (PE), and / or mixtures thereof. The particle size of the adhesive is from 1 μm to 1000 μm.

[0012] Among other characteristics, the first solvent is selected from alcohols, esters, and combinations thereof. The first solvent accounts for 5% to 10% by weight of the mixture in the second part of the extruder. The second solvent is selected from alcohols, esters, and combinations thereof. The second solvent accounts for 5% to 10% by weight of the mixture in the third part of the extruder.

[0013] Among other features, the method includes partially fibrillating the adhesive in a first part of the extruder, including fibrillating 20% ​​to 40% of the adhesive; partially fibrillating the adhesive in a second part of the extruder, including fibrillating 60% to 80% of the adhesive; and fibrillating the adhesive in a third part of the extruder, including fibrillating more than 90% of the adhesive.

[0014] Among other features, the extruder temperature is greater than 70°C and less than 150°C. The method includes outputting an active material layer onto a support film. The method includes outputting an active material layer as a self-supporting film. The method includes pressing and heating the active material layer. The method includes laminating the active material layer onto a current collector.

[0015] The present invention discloses the following solutions:

[0016] Option 1. A method for manufacturing a cathode electrode for a battery pack, comprising:

[0017] A dry powder mixture comprising active materials, conductive additives, and binders is supplied to the first extruder;

[0018] The active material, the conductive additive, and the binder are mixed in the first extruder;

[0019] The adhesive portion is fibrillated in the first extruder;

[0020] The mixture is supplied from the first extruder to the first inlet of the second extruder;

[0021] The solvent is supplied to the second inlet of the second extruder;

[0022] The active material, the conductive additive, the binder, and the solvent are mixed in the second extruder;

[0023] The adhesive is fibrillated in the second extruder; and

[0024] An active material layer is formed using an extrusion die arranged at the outlet of the second extruder.

[0025] Option 2. The method described in Option 1, wherein:

[0026] The first temperature of the first extruder is 19°C to 70°C, and

[0027] The second temperature of the second extruder is greater than 70°C.

[0028] Option 3. The method described in Option 1, wherein:

[0029] The adhesive is selected from polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), ethylene tetrafluoroethylene (ETFE), polyethylene (PE), and combinations thereof, and

[0030] The adhesive has a particle size of 1 μm to 1000 μm.

[0031] Option 4. The method according to Option 3, wherein the particle size of the adhesive is from 1 μm to 50 μm.

[0032] Option 5. The method described in Option 1, wherein:

[0033] The solvent is selected from alcohols, esters, and combinations thereof, and

[0034] The solvent comprises 5% to 20% by weight of the mixture.

[0035] Option 6. The method described in Option 1, wherein:

[0036] Fibrillating the adhesive portion in the first extruder includes fibrillating 10% to 40% of the adhesive, and

[0037] In the second extruder, fibrillating the adhesive includes fibrillating more than 90% of the adhesive.

[0038] Option 7. The method according to Option 2, wherein the second temperature of the mixture in the second extruder is below 150°C.

[0039] Option 8. The method according to Option 1, further comprising outputting the active material layer onto the support membrane.

[0040] Option 9. The method according to Option 1, further comprising outputting the active material layer as a self-supporting membrane.

[0041] Option 10. The method according to Option 1 further includes:

[0042] The active material layer is pressed and heated; and

[0043] The active material is laminated onto the current collector.

[0044] Option 11. A method for manufacturing a cathode electrode for a battery pack, comprising:

[0045] A dry powder mixture comprising cathode active material, conductive additives and binder is supplied to the first inlet of the extruder;

[0046] The cathode active material, the conductive additive, and the binder are mixed in the first part of the extruder;

[0047] The adhesive portion is fibrillated in the first part of the extruder;

[0048] The first solvent is supplied to the second part of the extruder;

[0049] The adhesive is further partially fibrillated in the second part of the extruder;

[0050] The second solvent is supplied to the third part of the extruder;

[0051] The adhesive is fibrillated in the third section of the extruder; and

[0052] An active material layer is formed using a slotted die disposed at the outlet of the third part of the extruder.

[0053] Option 12. The method according to Option 11, wherein:

[0054] The adhesive is selected from polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), ethylene tetrafluoroethylene (ETFE), polyethylene (PE), and / or mixtures thereof, and

[0055] The adhesive has a particle size of 1 μm to 1000 μm.

[0056] Option 13. The method according to Option 12, wherein:

[0057] The first solvent is selected from alcohols, esters, and combinations thereof, and

[0058] The first solvent accounts for 5% to 10% by weight of the mixture in the second part of the extruder.

[0059] Option 14. The method according to Option 13, wherein:

[0060] The second solvent is selected from alcohols, esters, and combinations thereof, and

[0061] The second solvent accounts for 5% to 10% by weight of the mixture in the third part of the extruder.

[0062] Option 15. The method according to Option 12, wherein:

[0063] In the first part of the extruder, fibrillating the adhesive portion includes fibrillating 20% ​​to 40% of the adhesive.

[0064] In the second part of the extruder, fibrillating the adhesive portion includes fibrillating 60% to 80% of the adhesive.

[0065] In the third part of the extruder, fibrillating the adhesive includes fibrillating more than 90% of the adhesive.

[0066] Option 16. The method according to Option 12, wherein the temperature of the extruder is greater than 70°C and less than 150°C.

[0067] Option 17. The method according to Option 11, further comprising outputting the active material layer onto a support membrane.

[0068] Option 18. The method according to Option 11, further comprising outputting the active material layer as a self-supporting membrane.

[0069] Option 19. The method according to Option 11, further comprising pressing and heating the active material layer.

[0070] Option 20. The method according to Option 11, further comprising laminating the active material layer onto the current collector.

[0071] The further applicability of this disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are intended to be illustrative only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0072] This disclosure will be more fully understood from the detailed embodiments and the accompanying drawings, in which:

[0073] Figure 1 This is a side cross-section of an example of a battery pack according to the present disclosure, comprising C cathode electrodes, A anode electrodes, and S separators;

[0074] Figure 2A and 2B These are side cross sections of examples of the cathode electrode and anode electrode according to this disclosure;

[0075] Figure 3 This is a functional block diagram of an example of a stepwise extrusion method for manufacturing a self-supporting active material layer according to the present disclosure;

[0076] Figure 4 This is a functional block diagram of another example of a stepwise extrusion method for manufacturing a self-supporting active material layer according to the present disclosure;

[0077] Figure 5 This is a functional block diagram illustrating an example of rolling and heating an active material layer according to this disclosure; and

[0078] Figure 6 This is a functional block diagram illustrating an example of laminating an active material layer onto a current collector according to the present disclosure.

[0079] In the accompanying drawings, reference numerals may be reused to designate similar and / or identical elements. Detailed Implementation

[0080] Although the battery pack according to this disclosure is shown in the context of an electric vehicle, the battery pack can be used in stationary applications and / or other applications.

[0081] This disclosure relates to a roll-to-roll (R2R) method for manufacturing active material layers for anode and / or cathode electrodes of battery packs using semi-dry powder. In some instances, stepwise extrusion methods are used to prepare thick electrodes, utilizing dry powder comprising cathode or anode active materials, conductive additives (e.g., carbon), binders (e.g., polytetrafluoroethylene (PTFE)), and manufacturing-friendly solvents (e.g., alcohols) as processing solvent media.

[0082] In some instances, the dry powder is actively premixed in a first extruder to homogenize the components and partially fibrillate the adhesive. The mixture from the first extruder is supplied to the inlet of a second extruder. A processing solvent is also added to the second extruder, further fibrillating the adhesive. In some instances, the second extruder outputs a self-supporting active material layer having a film thickness controlled by a die attached to the outlet of the second extruder. In some instances, the second extruder outputs the active material layer onto a support film (e.g., a polyester (PET) film).

[0083] Now for reference Figure 1 The battery pack 10 includes C cathode electrodes 20, A anode electrodes 40, and S separators 32 arranged in a predetermined order in the battery pack stack 12, where C, S, and A are integers greater than zero. The battery pack stack 12 is arranged in a housing 50. Liquid electrolyte 52 is added to the housing 50.

[0084] C cathode electrodes 20-1, 20-2, ..., and 20-C include a cathode active material layer 24 disposed on one or both sides of the cathode current collector 26. A anode electrodes 40-1, 40-2, ..., and 40-A include an anode active material layer 42 disposed on one or both sides of the anode current collector 46. S spacers 32-1, 32-2, ..., and 32-S are disposed between the C cathode electrodes 20 and the A anode electrodes 40.

[0085] In some instances, A anode electrodes 40 and C cathode electrodes 20 exchange lithium ions during charging / discharging. In some instances, the cathode active material layer 24 and / or the anode active material layer 42 include a coating comprising one or more active materials, one or more conductive additives, and / or one or more binder materials, which are cast or applied to one or both sides of the current collectors 26 and / or 46, respectively.

[0086] In some instances, the cathode current collector 26 and / or the anode current collector 46 comprises metal foil, metal mesh, perforated metal, 3D metal foam, and / or expanded metal. In some instances, the current collector is made of one or more materials selected from copper, stainless steel, brass, bronze, zinc, aluminum, and / or alloys thereof. The external tabs 28 and 48 are connected to the current collectors of the cathode and anode electrodes, respectively, and may be arranged on the same side or different sides of the battery pack stack 12. The external tabs 28 and 48 are connected to the terminals of the battery pack cells.

[0087] Now for reference Figure 2A and 2B An example of an electrode is shown. In Figure 2A The image shows one of the C cathode electrodes 20 in more detail. The cathode active material layer 24 includes a cathode active material 62, a conductive additive 64, and a binder 66. Figure 2B The image shows one of the A anode electrodes 40 in more detail. The anode active material layer 42 includes an anode active material 72, a conductive additive 74, and a binder 76.

[0088] Now for reference Figure 3 This illustrates a stepwise extrusion method using two or more extruders in series. A first extruder 110 includes a screw 112 rotatably arranged in a housing 115. A die 114 may be arranged at the outlet of the first extruder 110. The mixture output from the first extruder 110 is fed to a second extruder 120, which includes a screw 122 arranged in a housing 125. A die 124 (e.g., a slotted die) is arranged at the outlet of the second extruder 120.

[0089] A dry powder 130 comprising a mixture of cathode or anode active material, conductive filler, and binder is fed into the inlet 134 of a first extruder 110. The screw 112 of the first extruder 110 rotates within a housing 115 to mix and / or shear the dry powder. The first extruder 110 at least partially fibrillates the binder.

[0090] The mixture output from the first extruder 110 is fed into the first inlet 144 of the second extruder 120. A liquid feed 148 supplies solvent to the second inlet 150 of the second extruder 120. In some examples, the solvent is selected from alcohols, esters, and combinations thereof. The screw 122 of the second extruder 120 rotates within a housing 125 to mix and further shear the dry powder. The second extruder 120 further fibrillates the adhesive. The die 124 of the second extruder 120 outputs either an active material layer 160 as a self-supporting membrane or an active material layer 160 onto a support membrane 172 provided by rollers 170.

[0091] In some examples, the first extruder 110 fibrillates 10% to 40% of the adhesive. In some examples, the temperature of the mixture in the first extruder 110 is within a predetermined temperature range of 19°C to 70°C. In some examples, the solvent is present at 5% to 20% by weight of the mixture. In some examples, the temperature of the mixture in the second extruder 120 is maintained within a predetermined temperature range of 70°C to 150°C. In some examples, greater than 90% (e.g., 100%) of the adhesive is fibrillated in the second extruder 120. A heater (not shown) may be used to control the temperature of the first extruder 110 and / or the second extruder 120.

[0092] Now for reference Figure 4 This illustrates another step-by-step extrusion method using a single extruder. The extruder 210 includes a screw 212 rotatably arranged within a housing 213. The screw 212 of the extruder 210 rotates within the housing 213 to mix and shear dry powder and to stepwise fibrillate the adhesive. A die 214, such as a slotted die, is arranged at the outlet of the extruder 210.

[0093] A dry powder 220 comprising an anode or cathode active material, conductive filler, and binder is fed into the inlet 224 of the first section of the extruder 210. The dry powder is mixed, and the binder is partially fibrillated in the first section. A first liquid feed 230 feeds solvent into the second inlet 234 of the second section of the extruder 210. The mixture is mixed / sheared, and the binder is further fibrillated in the second section of the extruder 210. A second liquid feed 240 feeds solvent into the second inlet 234 of the third section of the extruder 210. The mixture is mixed / sheared, and the binder is further fibrillated in the third section of the extruder 210. The die 214 of the extruder 210 outputs either an active material layer 250 as a self-supporting membrane or an active material layer 250 onto a support membrane 262 supplied by roller 260.

[0094] In some instances, the first solvent is selected from alcohols, esters, and combinations thereof. The first solvent accounts for 5% to 10% by weight of the mixture in the second section of extruder 210. The second solvent is selected from alcohols, esters, and combinations thereof. In some instances, the first and second solvents are the same. The second solvent accounts for 5% to 10% by weight of the mixture in the third section of extruder 210.

[0095] The adhesive is fibrillated in a stepwise manner. In other words, the adhesive is fibrillated continuously in different sections of extruder 210. In some examples, 20% to 40% of the adhesive portion is fibrillated in the first section of extruder 210. 60% to 80% of the adhesive portion is fibrillated in the second section of extruder 210. More than 90% (e.g., 100%) of the adhesive is fibrillated in the third section of extruder 210. In some examples, the temperature of the mixture in extruder 210 is greater than 70°C and less than 150°C. A heater (not shown) may be used to control the temperature of extruder 210.

[0096] Now for reference Figure 5 In some instances, the active material layer 160 / 250 passes through first sets of rollers 310 and 312 and second sets of rollers 320 and 322 to reduce the film thickness. After rolling and pressing, the active material layer is heated to a temperature of 19°C to 150°C in an oven 330 and collected on roller 334. In some instances, the active material layer 160 / 250 is heated to a temperature of 80°C to 100°C.

[0097] Now for reference Figure 6 Roller 350 provides an active material layer 352 between rollers 366 and 368. Roller 360 provides a current collector 364 between rollers 366 and 368. Rollers 366 and 368 press and / or heat the active material layer 352 and the current collector 364 to form an electrode 372 (collected on roller 374). In some instances, a heat-sensitive adhesive may be applied to one or both finish surfaces to adhere the active material layer 352 and the current collector 364.

[0098] In some examples, the adhesive is selected from polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), ethylene tetrafluoroethylene (ETFE), polyethylene (PE), or combinations thereof. In some examples, the particle size of the adhesive is from 1 μm to 1000 μm. In some examples, the particle size of the adhesive is from 100 μm to 170 μm (e.g., 110 μm or 150 μm). In some examples, the particle size of the adhesive is from 1 μm to 50 μm.

[0099] In some instances, the mixture has a solids content of 75 to 95% by weight. In other instances, the mixture has a solids content of 80 to 90% by weight.

[0100] In some instances, the solvent is selected from alcohols, esters, and combinations thereof. In some instances, the solvent is manufacturing-friendly. In some instances, the solvent accounts for 5 to 40% by mass. In some instances, the solvent is added twice in equal or unequal portions. Figure 4 In the extruder 210.

[0101] The foregoing description is merely exemplary and is in no way intended to limit this disclosure, its application, or its use. The broad teachings of this disclosure can be implemented in various forms. Therefore, although this disclosure includes specific examples, its true scope should not be limited thereto, as other modifications will become apparent upon examination of the drawings, specification, and the following claims. It should be understood that one or more steps within the method may be performed in a different order (or simultaneously) without altering the principles of this disclosure. Furthermore, although the embodiments are described above as having certain features, any one or more features described with respect to any embodiment of this disclosure may be implemented in any other embodiment and / or combined with features of any other embodiment, even if such combination is not explicitly described. In other words, the embodiments are not mutually exclusive, and substitution of one or more embodiments for each other remains within the scope of this disclosure.

[0102] Various terms are used to describe spatial and functional relationships between components (e.g., between modules, circuit elements, semiconductor layers, etc.), including “connection,” “joint,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as “direct,” when describing the relationship between the first and second components in the foregoing disclosure, the relationship can be a direct relationship in which no other intermediary components exist between the first and second components, or an indirect relationship in which one or more intermediary components exist between the first and second components (spatially or functionally). The phrase “at least one of A, B, and C” as used herein should be interpreted as referring to the logic of OR (A or B or C) using non-exclusive logic, and should not be interpreted as referring to “at least one of A, at least one of B, and at least one of C.”

Claims

1. A method for manufacturing a cathode electrode for a battery pack, comprising: A dry powder mixture comprising active materials, conductive additives, and binders is supplied to the first extruder; The active material, the conductive additive, and the binder are mixed in the first extruder; The adhesive portion is fibrillated in the first extruder; The mixture is supplied from the first extruder to the first inlet of the second extruder; The solvent is supplied to the second inlet of the second extruder; The active material, the conductive additive, the binder, and the solvent are mixed in the second extruder; The adhesive is fibrillated in the second extruder; and An active material layer is formed using an extrusion die arranged at the outlet of the second extruder.

2. The method according to claim 1, wherein: The first temperature of the first extruder is 19°C to 70°C, and The second temperature of the second extruder is greater than 70°C.

3. The method according to claim 1, wherein: The adhesive is selected from polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), ethylene tetrafluoroethylene (ETFE), polyethylene (PE), and combinations thereof, and The adhesive has a particle size of 1 μm to 1000 μm.

4. The method according to claim 3, wherein the particle size of the adhesive is from 1 μm to 50 μm.

5. The method according to claim 1, wherein: The solvent is selected from alcohols, esters, and combinations thereof, and The solvent comprises 5% to 20% by weight of the mixture.

6. The method according to claim 1, wherein: Fibrillating the adhesive portion in the first extruder includes fibrillating 10% to 40% of the adhesive, and In the second extruder, fibrillating the adhesive includes fibrillating more than 90% of the adhesive.

7. The method of claim 2, wherein the second temperature of the mixture in the second extruder is below 150°C.

8. The method of claim 1, further comprising exporting the active material layer onto a support membrane.

9. The method of claim 1, further comprising outputting the active material layer as a self-supporting membrane.

10. The method of claim 1, further comprising: The active material layer is pressed and heated; and The active material is laminated onto the current collector.

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