Single-sided roll-in insertion of thick lithium into 3D current collectors

Abstract

A method for manufacturing an electrode of a battery cell includes: supplying an active material layer, a current collector, and a dummy current collector between a first roller and a second roller; using one of the first roller and the second roller to bias the current collector into the active material layer using the dummy current collector to below an outer surface of the active material layer; and removing the dummy current collector from the active material layer.

Description

Technical Field

[0001] The information provided in this section is for the purpose of generally presenting the context of the present disclosure. To the extent described in this section, the work of the presently named inventors and aspects of the description that may not constitute prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art to the present disclosure.

[0002] The present disclosure relates to battery cells, and more particularly to current collectors for battery cells. Background Art

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

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

[0005] A method for manufacturing an electrode for a battery cell, comprising: supplying an active material layer, a current collector, and a dummy current collector between a first roller and a second roller; using one of the first roller and the second roller, using the dummy current collector to bias the current collector into the active material layer to below the outer surface of the active material layer; and removing the dummy current collector from the active material layer.

[0006] In other features, the electrode includes an anode electrode, the active material layer includes a lithium layer. The lithium layer has a thickness greater than 60 μm. The current collector includes an anode current collector. The current collector includes a three-dimensional current collector. The current collector includes a metal mesh. The current collector and the dummy current collector have the same spacing and pattern. After removing the dummy current collector, the active material layer is rolled one or more times to enclose the current collector in the active material layer.

[0007] In other features, the dummy current collector includes a substrate and a pattern of raised portions disposed on the substrate. The pattern of raised portions is aligned with a pattern of conductive lines of the current collector. The dummy current collector includes a continuous layer.

[0008] A method for manufacturing an electrode for a battery cell includes supplying an active material layer and a current collector between a first roller and a second roller. The first roller includes a pattern of raised portions corresponding to a pattern of conductors of the current collector. The method includes using the pattern of raised portions of the first roller to bias the current collector into the active material layer to below an outer surface of the active material layer.

[0009] In other features, the electrode comprises an anode electrode, the active material layer comprises a lithium layer, the lithium layer has a thickness greater than 60 μm, the current collector comprises an anode current collector, the current collector comprises a three-dimensional current collector, and the current collector comprises a metal mesh.

[0010] In other features, the patterns of the conductive lines and raised portions of the current collector have the same pitch and pattern. The method includes rolling the active material layer one or more times to enclose the current collector in the active material layer.

[0011] The present invention may also include the following aspects.

[0012] 1. A method for manufacturing an electrode for a battery cell, comprising:

[0013] supplying an active material layer, a current collector, and a dummy current collector between a first roller and a second roller;

[0014] biasing the current collector into the active material layer using the dummy current collector to below an outer surface of the active material layer using one of the first roller and the second roller; and

[0015] The dummy current collector is removed from the active material layer.

[0016] 2. The method according to claim 1, wherein the electrode comprises an anode electrode, and the active material layer comprises a lithium layer.

[0017] 3. The method according to claim 2, wherein the lithium layer has a thickness greater than 60 μm.

[0018] 4. The method according to Option 1, wherein the current collector comprises an anode current collector.

[0019] 5. A method according to Option 2, wherein the collector comprises a three-dimensional collector.

[0020] 6. A method according to Option 5, wherein the collector comprises a metal mesh.

[0021] 7. The method according to Option 1, wherein the current collector and the dummy current collector have the same pitch and pattern.

[0022] 8. The method according to Option 1 further includes: after removing the dummy current collector, rolling the active material layer one or more times to enclose the current collector in the active material layer.

[0023] 9. The method according to Option 1, wherein the dummy current collector includes a substrate and a pattern of raised portions arranged on the substrate.

[0024] 10. The method according to claim 9, wherein the pattern of the raised portions is aligned with the pattern of the conductive wires of the current collector.

[0025] 11. The method according to Option 9, wherein the dummy current collector comprises a continuous layer.

[0026] 12. A method for manufacturing an electrode for a battery cell, comprising:

[0027] supplying an active material layer and a current collector between a first roller and a second roller;

[0028] wherein the first roller comprises a pattern of raised portions corresponding to a pattern of conductive lines of the current collector; and

[0029] The current collector is biased into the active material layer, below the outer surface of the active material layer, using the pattern of raised portions of the first roller.

[0030] 13. The method according to claim 12, wherein the electrode comprises an anode electrode, and the active material layer comprises a lithium layer.

[0031] 14. The method according to claim 13, wherein the lithium layer has a thickness greater than 60 μm.

[0032] 15. The method according to Option 12, wherein the current collector comprises an anode current collector.

[0033] 16. A method according to Option 11, wherein the collector comprises a three-dimensional collector.

[0034] 17. A method according to Option 16, wherein the collector comprises a metal mesh.

[0035] 18. The method according to claim 11, wherein the conductive wires of the current collector and the pattern of the raised portions have the same pitch and pattern.

[0036] 19. The method according to Option 12 further includes: rolling the active material layer one or more times to enclose the current collector in the active material layer.

[0037] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the accompanying drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present disclosure will become more fully understood from the detailed description and accompanying drawings, in which:

[0039] Figure 1 is a side cross-sectional view of an example of a battery cell according to the present disclosure;

[0040] Figure 2 is a side view of an example of a method for manufacturing an anode electrode;

[0041] Figure 3 is a side cross-sectional view of an example of an anode electrode;

[0042] Figure 4 An example of a single-sided method for making an anode electrode is shown;

[0043] Figure 5A is a side cross-sectional view of an example of an anode electrode;

[0044] Figure 5B is a plan view of the surface of the anode electrode;

[0045] Fig. 6A and 6B An example of a single-sided method for manufacturing an anode electrode according to the present disclosure is shown;

[0046] Figures 7A to 7D is a side cross-sectional view of an example of an anode electrode during single-sided fabrication according to the present disclosure; and

[0047] Figure 8 to 1 FIG. 0 shows another example of a single-sided method for manufacturing an anode electrode according to the present disclosure.

[0048] Among the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0049] Although the battery cells according to the present disclosure are shown in the context of electric vehicles, the battery cells can be used for stationary applications and / or other applications. Although the following description is illustrated by a single-sided manufacturing method for embedding an anode current collector in an active material layer of an anode electrode, the single-sided manufacturing method can be used to embed a current collector in an active material layer of other types of electrodes.

[0050] The present disclosure relates to a method for inserting a current collector, such as a three-dimensional current collector (3DCC), into a lithium metal layer (e.g., lithium foil) from one side of the lithium metal layer. One advantage of inserting the current collector into the lithium layer from one side is that thicker lithium layers (e.g., greater than 60 μm) can be used. Existing double-sided lamination processes typically use two thinner layers (less than 50 μm each). Thinner layers are more difficult to handle and more expensive to manufacture or purchase. In other words, a lithium layer with a thickness of 60 μm used in the single-sided insertion method is equivalent to two 30 μm lithium layers used for double-sided lamination.

[0051] The anode electrode manufactured using the single-sided rolling insertion described herein has a roughly symmetrical distribution of lithium around the anode current collector. In order to ensure that lithium is symmetrically distributed around the anode current collector, a dummy current collector or a surface including a pattern of a raised portion is used during the rolling / embedding process to bias the anode current collector into the lithium layer in a position spaced apart from the outer surface of the lithium layer. Lithium will flow into the negative space of the patterned opposite surface (or "dummy net"), which enables lithium to flow over the current collector surface. A second set of rollers is then used to squeeze and / or heat the anode electrode to close the gap and smooth the surface of the lithium layer.

[0052] Reference now Figure 1 , the battery cell 10 includes C cathode electrodes 20, A anode electrodes 40, and S separators 32 arranged in a predetermined order in the battery cell stack 12. The battery cell stack 12 is located in a housing 50 including an electrolyte, where C, S, and A are integers greater than zero. The C cathode electrodes 20-1, 20-2, ..., and 20-C include a cathode active material layer 24 arranged on one or both sides of a cathode current collector 26.

[0053] In some examples, the A anode electrodes 40 and the C cathode electrodes 20 exchange lithium ions during charge and discharge. The A anode electrodes 40-1, 40-2, ... and 40-A include an anode active material layer 42 disposed on one or both sides of an anode current collector 46. In some examples, the cathode active material layer 24 includes a coating including one or more active materials, one or more conductive additives and / or one or more binder materials applied to the current collector.

[0054] In some examples, cathode current collector 26 and anode current collector 46 include metal foil, metal mesh, perforated metal, 3D metal foam and / or expanded metal. In some examples, the current collector is made of one or more materials selected from the group consisting of copper, stainless steel, brass, bronze, zinc, aluminum and / or alloys thereof. External tabs 28 and 48 are connected to the current collectors of the cathode electrode and the anode electrode, respectively, and can be arranged on the same or opposite sides of the battery cell stack 12, and the external tabs 28 and 48 are connected to the terminals of the battery cells.

[0055] Reference now Figure 2 and 3 , a method for manufacturing an anode electrode is shown. Figure 2 In the embodiment, rollers 124 and 126 supply lithium layers 128 and 130, such as lithium foil, between rollers 138 and 140, respectively. Roller 134 supplies anode current collector 136 between lithium layers 128 and 130. Rollers 138 and 140 compress (and optionally heat) lithium layer 128, anode current collector 136, and lithium layer 130 to form a composite anode electrode. Because lithium layers 128 and 130 are soft, anode current collector 136 is pressed into or embedded in the adjacent surfaces of lithium layers 128 and 130, such as Figure 3 shown.

[0056] Typically, lithium layers 128 and 130 are thin foil layers with a thickness of less than 50 μm (e.g., 30 μm). Composite anode electrode 144 has a thickness in the range of 60 μm to 100 μm. However, thin lithium foil layers are expensive to manufacture and difficult to handle during roll-to-roll or other types of processing.

[0057] Reference now Figures 4 to 5B , showing a single-sided approach for making the anode electrode. Figure 4 , roller 224 supplies lithium layer 228 between rollers 238 and 240. Roller 234 supplies anode current collector 236 adjacent to lithium layer 228 between rollers 238 and 240. Rollers 238 and 240 compress (and optionally heat) lithium layer 228 and anode current collector 236. Because lithium layer 228 is soft, anode current collector 236 is at least partially pressed into one side of lithium layer 228, as shown in FIG. Figure 5A As shown. Anode current collector 236 is not symmetrically located near the middle of lithium layer 228. Figure 5B , a side of the anode current collector 236 is exposed on one side of the lithium layer 228.

[0058] Reference now Figures 6A to 7D , showing a single-sided approach for making the anode electrode. Fig. 6A and 6B , lithium layer 310, anode current collector 314, and dummy current collector 318 are arranged in a stack and pressed (and optionally heated) between rollers 322 and 324. Although lithium layer 310, anode current collector 314, and dummy current collector 318 are shown as discrete layers, continuous layers may be used.

[0059] In some examples, dummy current collector 318 is made of the same material and has the same spacing and / or pattern as anode current collector 314. In other examples, dummy current collector 318 is made of a different material than anode current collector 314 and has the same spacing and / or pattern as anode current collector 314. In other examples, the dummy current collector has a different spacing / pattern than the anode current collector because changing the pattern may be a way to help lithium flow into the negative space.

[0060] exist Figure 6B and 7A In the embodiment of the present invention, rollers 322 and 324 press dummy current collector 318 against anode current collector 314 to push anode current collector 314 into lithium layer 310. Figure 7B In the embodiment, the dummy current collector 318 is removed after extrusion. Figure 7C In the embodiment, the lithium layer 310 and the anode current collector 314 are pressed and / or heated one or more times by one or more pairs of additional rollers to smooth the outer surface of the lithium layer and reduce or remove the openings 320 (e.g., Fig.7D 322 in FIG. 1 ).

[0061] Since only a single lithium layer is used, the thickness of the lithium layer can be greater than or equal to 60 μm in some examples (which is consistent with Figure 2 and 3 The two lithium layers 128 and 130 used in the invention are significantly cheaper than those with a thickness of less than 50 μm. Thicker lithium layers are easier to handle due to increased ductility and / or tear resistance.

[0062] In some examples, the lithium layer is symmetrically arranged around the anode current collector after insertion. For example, after the lithium layer is inserted and smoothed, the anode current collector 136 is located in the range of 45% to 55% of the thickness of the lithium layer 130. For example, the anode current collector has a predetermined thickness (e.g., >= 60 μm), and after symmetrical insertion of the anode current collector and subsequent rolling, the anode electrode has a thickness less than or equal to the predetermined thickness.

[0063] Reference now Figures 8 to 10B , shows other methods for single-sided fabrication of anode electrodes. Figure 8 , a method for making an anode electrode is shown. Roller 424 supplies dummy current collector 428 as a continuous layer between rollers 438 and 440, respectively. Roller 426 supplies lithium layer 430 between rollers 438 and 440, respectively. Roller 434 supplies anode current collector 436 between dummy current collector 428 and lithium layer 430. Rollers 438 and 440 press dummy current collector 428 into anode current collector 436 to position anode current collector 436 below the outer surface of lithium layer 430. In some examples, dummy current collector 428 is guided back to roller 424 by one or more additional rollers 452 and 454.

[0064] exist Fig.9A and 9B In, a method for manufacturing an anode electrode is shown. Fig.9A , roller 524 supplies dummy current collector 528 as a continuous layer between rollers 538 and 540, respectively. Roller 526 supplies lithium layer 530 between rollers 538 and 540, respectively. Roller 534 supplies anode current collector 536 between dummy current collector 528 and lithium layer 530. Rollers 538 and 540 press dummy current collector 528 against anode current collector 536 to position anode current collector 536 below the outer surface of lithium layer 530. In some examples, dummy current collector 528 is routed around roller 538 back onto roller 524.

[0065] In some examples, dummy current collector 528 is made of the same material and has the same spacing and / or pattern as anode current collector 536. In other examples, dummy current collector 528 is made of a different material than anode current collector 536 and has the same spacing and / or pattern as anode current collector 536. In other examples, dummy current collectors can technically have a different spacing / pattern than the anode current collector, as changing the pattern can be a way to help lithium flow into the negative space.

[0066] In other examples, dummy current collector 528 includes substrate 548 including a pattern of raised portions 550 having the same wire pattern and spacing and / or pattern as anode current collector 536, such as Fig. 9B The pattern of raised portions 550 can be made by additive manufacturing, conventional machining, and / or electrodeposition of a patterned layer onto substrate 548. The pattern of raised portions 550 can be made using polymers, metals, and / or other types of materials that do not plastically deform under rolling pressure (while still being flexible enough to wrap around a rolling surface).

[0067] exist Fig. 10A and 10B In, a method for manufacturing an anode electrode is shown. Fig. 10A In the embodiment, roller 626 supplies lithium layer 630 between rollers 638 and 640. In some examples, roller 638 includes a pattern of raised portions 650 ( Fig. 10B ), and roller 640 is smooth. Roller 634 supplies anode current collector 636 between rollers 638 and 640. Rollers 638 and 640 squeeze and / or heat anode current collector 636 and lithium layer 630. The pattern of raised portion 650 presses anode current collector 636 into lithium layer 630. The pattern of raised portion 650 has the same wire pattern and spacing and / or pattern as anode current collector 636. Anode current collector 636 and lithium layer 630 are squeezed by one or more pairs of additional rollers 658 and 660 to make lithium layer 630 smooth.

[0068] The pattern of raised portions 650 can be made by additive manufacturing, conventional machining, and / or electrodeposition of a patterned layer onto the outer surface of the roller. The pattern of raised portions 650 can be made using a polymer, metal, and / or another material that does not plastically deform under rolling pressure while still being flexible enough to wrap around the rolling surface.

[0069] In some examples, the pattern of raised portions 650 (and / or the areas therebetween) includes a non-stick coating 651 to prevent adhesion of the lithium layer to facilitate easier separation of the lithium layer. In some examples, the non-stick coating 651 includes a ceramic coating such as chromium oxide, but other coatings may be used.

[0070] In some examples, the pattern of raised portions mimics the pattern of the anode current collector (eg, a mesh pattern).Additional patterns may be used for current collectors having other patterns, such as angled lines, parallel lines, raised circles, and / or truncated cones.

[0071] The foregoing description is essentially only illustrative, and is not intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because after studying the drawings, the specification and the appended claims, other modifications will become apparent. It should be understood that, without changing the principles of the present disclosure, one or more steps in the method can be performed in different orders (or simultaneously). In addition, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure can be implemented in the features of any one of the other embodiments and / or combined with the features of any one of the other embodiments, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the replacement of one or more embodiments with each other remains within the scope of the present disclosure.

[0072] Various terms are used to describe the spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.), including "connected," "engaged," "coupled," "adjacent," "next to," "on top," "above," "below," and "disposed." Unless explicitly described as "directly," when the relationship between a first and a second element is described in the above disclosure, the relationship may be a direct relationship in which no other intervening elements exist between the first and second elements, but may also be an indirect relationship in which one or more intervening elements exist (spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be interpreted to mean a logic (A ORB OR C) using a non-exclusive logical OR, and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C."

[0073] In the drawings, the direction of the arrows, as indicated by the arrows, generally represents the flow of information (e.g., data or instructions) of interest to the illustration. For example, when element A and element B exchange various information, but the information sent from element A to element B is relevant to the illustration, the arrow may be directed from element A to element B. The unidirectional arrow does not imply that no other information is sent from element B to element A. In addition, for information sent from element A to element B, element B may send a request for the information or a confirmation of receipt of the information to element A.

Claims

1. A method for manufacturing an electrode for a battery cell, comprising: supplying an active material layer, a current collector, and a dummy current collector between a first roller and a second roller; biasing the current collector into the active material layer using the dummy current collector to below an outer surface of the active material layer using one of the first roller and the second roller; as well as The dummy current collector is removed from the active material layer.

2. The method according to claim 1, wherein: The electrode includes an anode electrode, and the active material layer includes a lithium layer.

3. The method according to claim 2, wherein: The lithium layer has a thickness greater than 60 μm.

4. The method according to claim 1, wherein: The current collector includes an anode current collector.

5. The method according to claim 2, wherein: The current collector includes a three-dimensional current collector.

6. The method according to claim 5, wherein: The current collector comprises a metal mesh.

7. The method according to claim 1, wherein: The current collectors and the dummy current collectors have the same pitch and pattern.

8. The method according to claim 1, further comprising: After removing the dummy current collector, the active material layer is rolled one or more times to enclose the current collector in the active material layer.

9. The method according to claim 1, wherein: The dummy current collector includes a substrate and a pattern of raised portions arranged on the substrate.

10. The method according to claim 9, wherein: The pattern of the raised portions is aligned with the pattern of the conductive wires of the current collector.

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