Battery anode with alternating active layers

Abstract

An anode for a rechargeable battery cell includes an electrode substrate and a current collector secured to the electrode substrate. The anode also includes an active layer disposed on the current collector and having a discrete plurality of first material portions and at least one second material portion arranged in an alternating pattern. Each discrete material portion is aligned parallel to the current collector. The active layer is configured to embed transient ions during charging of the battery cell and to deembed transient ions during discharging of the battery cell. A method of manufacturing such an anode for a rechargeable battery cell is also contemplated.

Description

Technical Field

[0001] The present disclosure relates to battery anodes having alternating active layers and methods of making the same. Background Art

[0002] Electrochemical energy storage devices, such as lithium-ion batteries, can be used to power a variety of items, such as toys, consumer electronics, and motor vehicles. Typically, a battery includes two electrodes and an electrolyte assembly and / or a separator. One of the two electrodes typically serves as the positive electrode or cathode and the other serves as the negative electrode or anode. Electrochemical battery cells can be broadly divided into primary batteries and secondary batteries. Primary batteries, also called disposable batteries, are intended to be used until exhausted, after which they are replaced with new batteries. Secondary batteries, more commonly called rechargeable batteries, employ specific chemistries that allow such batteries to be repeatedly recharged and reused.

[0003] Rechargeable batteries may be in solid form, liquid form, or a solid-liquid hybrid. A separator and / or an electrolyte may be disposed between the anode and the cathode. In rechargeable lithium-ion batteries, an electrolyte is typically used to conduct lithium ions between the electrodes. Typically, lithium-ion batteries operate by reversibly transferring lithium ions back and forth between the anode and the cathode. For example, during battery charging, lithium ions may move from the cathode to the anode, while during battery discharge, the lithium ions move in the opposite direction. The ability of the battery electrodes to repeatedly insert or embed lithium ions into their respective structures and to extract or deintercalate lithium ions therefrom determines the actual long-term charge capacity of the battery cell. Therefore, material depletion in the corresponding electrode structures during extended cycles may have a negative impact on the long-term performance of the battery cell. Summary of the invention

[0004] An anode for a rechargeable battery cell includes an electrode substrate and a current collector fixed to the electrode substrate. The anode also includes an active layer disposed on the current collector and having a plurality of discrete first material portions and at least one second material portion arranged in an alternating pattern. Each discrete material portion is aligned parallel to the current collector. The active layer is configured to intercalate transient ions during charging of the battery cell and deintercalate transient ions during discharging of the battery cell.

[0005] Each first material portion may contain graphite and each second material portion may contain silicon.

[0006] Each second material portion may include pure silicon, silicon alloy, SiO x (Silicon oxide), LiSiO x (lithium silicon oxide) or Si-C (silicon carbon composite).

[0007] One of the plurality of first material portions may be positioned adjacent to and in direct contact with the current collector.

[0008] The anode may include a plurality of second material portions such that each second material portion is disposed between and in contact with two first material portions.

[0009] The current collector may be defined by a length and a width. The alternating pattern may be defined by a layered structure such that each of the discrete plurality of first material portions and at least one second material portion spans each of the length and width of the current collector.

[0010] The first material and the second material may each include respective conductivity enhancing particles and a polymer binder.

[0011] The active layer may be generated by applying a separate slurry coating of each respective first material portion and second material portion onto a current collector.

[0012] The active layer may be produced by simultaneously slurry coating the first material portion and the second material portion onto the current collector.

[0013] The active layer may be produced by one of 3D printing and co-extrusion printing of the corresponding first material portion and the second material portion.

[0014] Also contemplated are methods of making such anodes for use in rechargeable battery cells, such as lithium-ion battery cells.

[0015] The present invention discloses the following technical solutions.

[0016] Scheme 1. An anode for a rechargeable battery cell, comprising:

[0017] Electrode substrate;

[0018] a current collector secured to an electrode substrate; and

[0019] an active layer disposed on the current collector and having a discrete plurality of first material portions and at least one second material portion arranged in an alternating pattern;

[0020] in:

[0021] Each material portion is aligned parallel to the current collector; and

[0022] The active layer is configured to intercalate transient ions during charging of the battery cell and to deintercalate transient ions during discharging of the battery cell.

[0023] Option 2. An anode according to Option 1, wherein each first material portion comprises graphite and each second material portion comprises silicon.

[0024] Option 3. The anode according to Option 2, wherein the second material portion comprises pure silicon, silicon alloy, SiO x(Silicon oxide), LiSiO x One of (lithium silicon oxide) and Si-C (silicon carbon composite).

[0025] Option 4. An anode according to Option 1, wherein one of the plurality of first material portions is placed adjacent to and in direct contact with a current collector.

[0026] Option 5. An anode according to Option 4, wherein the at least one second material portion comprises a plurality of second material portions, and wherein each second material portion is arranged between and in contact with two first material portions.

[0027] Option 6. An anode according to Option 4, wherein the current collector is defined by a length and a width, and wherein the alternating pattern is defined by a layered structure such that each of the discrete plurality of first material portions and at least one second material portion spans each of the length and width of the current collector.

[0028] Option 7. The anode according to Option 1, wherein the first material and the second material each contain corresponding conductivity enhancing particles and a polymer binder.

[0029] Embodiment 8. The anode according to embodiment 1, wherein the active layer is generated by applying a separate slurry of each corresponding first material portion and second material portion onto a current collector.

[0030] Option 9. The anode according to Option 1, wherein the active layer is generated by simultaneously slurry-coating the first material portion and the second material portion onto a current collector.

[0031] Option 10. The anode according to Option 1, wherein the active layer is generated by one of 3D printing and co-extrusion printing of the corresponding first material portion and the second material portion.

[0032] Embodiment 11. A method of manufacturing an anode for a rechargeable battery cell, the method comprising:

[0033] providing a current collector; and

[0034] An active layer having a discrete plurality of first material portions and at least one second material portion is deposited onto a current collector, including arranging the first material portions and the second material portions in an alternating pattern and aligned parallel to the current collector to produce an anode.

[0035] Option 12. A method according to Option 11, wherein each first material portion comprises graphite and each second material portion comprises silicon.

[0036] Option 13. The method according to Option 12, wherein the second material portion comprises pure silicon, silicon alloy, SiO x(Silicon oxide), LiSiO x One of (lithium silicon oxide) and Si-C (silicon carbon composite).

[0037] Option 14. The method according to Option 11 also includes placing one of the multiple first material portions adjacent to the current collector and in direct contact with the current collector.

[0038] Option 15. A method according to Option 14, wherein the at least one second material portion includes a plurality of second material portions, and wherein arranging each of the discrete plurality of first material portions and second material portions in an alternating pattern and aligning them parallel to the current collector includes arranging each second material portion between and in contact with two first material portions.

[0039] Option 16. A method according to Option 14, wherein the collector is defined by a length and a width, and wherein the alternating pattern is defined by a layered structure such that each of the discrete plurality of first material portions and at least one second material portion spans each of the length and width of the collector.

[0040] Option 17. The method according to Option 11, wherein depositing the active layer onto the current collector comprises applying a separate slurry of each corresponding first material portion and second material portion onto the current collector.

[0041] Option 18. The method according to Option 11, wherein depositing the active layer onto the current collector comprises simultaneously slurry-coating the first material portion and the second material portion onto the current collector.

[0042] Option 19. A method according to Option 11, wherein depositing the active layer onto the current collector comprises one of 3D printing and co-extrusion printing of the corresponding first material portion and the second material portion.

[0043] Embodiment 20. An anode for a rechargeable battery cell, comprising:

[0044] an electrode substrate; and

[0045] a current collector secured to an electrode substrate; and

[0046] an active layer disposed on the current collector and having a discrete plurality of graphite portions and silicon-containing portions arranged in an alternating pattern defined by a layered structure;

[0047] in:

[0048] Each of the graphite portion and the silicon-containing portion is aligned parallel to the current collector;

[0049] Each silicon-containing portion is in contact with two graphite portions;

[0050] One of the graphite portions is positioned adjacent to and in direct contact with a current collector; and

[0051] The active layer is configured to intercalate lithium ions during charging of the battery cell and to deintercalate lithium ions during discharging of the battery cell.

[0052] The above features and advantages and other features and advantages of the present disclosure will become apparent from the following detailed description of one or more embodiments and one or more best modes for carrying out the described disclosure when taken in conjunction with the accompanying drawings and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a schematic diagram of an energy storage battery for powering a load according to the present disclosure, the energy storage battery being shown as a lithium-ion (Li-ion) battery pack relative to a three-dimensional (XYZ) space, and having an anode composed of layered first material portions and second material portions arranged in an alternating pattern and aligned parallel to a current collector, specifically depicting a plurality of first material portions and a second material portion sandwiched therebetween.

[0054] Figure 2 According to another embodiment of the present disclosure Figure 1 Schematic close-up plan view of an anode shown in , except that a layered plurality of first material portions and a plurality of second material portions arranged in an alternating pattern are depicted.

[0055] Figure 3 is a schematic close-up of an anode structure including conductivity enhancing particles and binder particles according to the present disclosure.

[0056] Figure 4 Generally shows a method for constructing a Figure 1-3 3D printing and co-extrusion printing manufacturing methods of the electrodes shown.

[0057] Figure 5 The invention is shown for constructing Figure 1-3 One embodiment of a slurry coating method for manufacturing an electrode is shown.

[0058] Figure 6 The invention is shown for constructing Figure 1-3 One embodiment of a slurry coating method for manufacturing an electrode is shown.

[0059] Figure 7 Shows the use of Figure 4-6 The device and method are manufactured with Figure 1-3 A flow chart of a method for forming an alternating pattern of a rechargeable battery cell anode is shown. DETAILED DESCRIPTION

[0060] Those of ordinary skill in the art will recognize that the use of terms such as "above", "below", "upward", "downward", "top", "bottom", "left", "right", etc. to describe the drawings does not represent a limitation on the scope of the present disclosure as defined by the appended claims. In addition, the teachings may be described herein in terms of functional and / or logical block components and / or various processing steps. It should be recognized that such block components may include multiple hardware, software, and / or firmware components configured to perform the specified functions.

[0061] refer to Figure 1 , depicting an electrical energy storage cell 10 for powering a load 12. As shown, the electrical energy storage cell 10 has an anode (negative electrode) 14, a cathode (positive electrode) 16, and a non-aqueous electrolyte 18 of one of a solid, liquid, gel, and polymer (e.g., polymer-based) surrounding the anode, cathode, and filling a separator 20. The energy storage cell 10 is specifically shown as a lithium-ion (Li-ion) battery. The anode 14 can be made of lithium, graphite, silicon, silicon oxide, and various other suitable materials. Although the cathode 16 is typically made of a lithium-ion battery cathode material, such as lithium manganese oxide, lithium iron phosphate, lithium nickel / manganese / cobalt oxide, various other suitable materials can also be used.

[0062] Lithium-ion batteries are rechargeable electrochemical batteries known for their high specific energy and low self-discharge. Lithium-ion batteries can be used to power a variety of items, such as toys, consumer electronics, and motor vehicles. Although the electrical energy storage cell 10 is specifically shown as a lithium-ion battery, it is broadly contemplated that other battery chemistries and corresponding structures are also contemplated. The vehicles of the present invention may include, but are not limited to, commercial vehicles, industrial vehicles, passenger vehicles, aircraft, ships, trains, and the like. It is also contemplated that the vehicle may be a mobile platform, such as an aircraft, an all-terrain vehicle (ATV), a boat, a personal mobility device, a robot, and the like, as suitable applications of the present disclosure.

[0063] In a lithium-ion battery, lithium ions move from the anode 14 through the electrolyte 18 to the cathode 16 during discharge and back during charging. Lithium-ion batteries use lithium metal oxides, such as Li-NMC, Li-NMCA, LMO, NMO, LFP, etc. as the positive electrode material, and graphite is usually used for the negative electrode. Typically, the reactants of the electrochemical reaction in the lithium-ion battery 10 are the anode material and the cathode material, both of which are compounds that can accommodate lithium atoms, and the reaction occurs at the electrode particle / electrolyte interface. During discharge, the oxidation half-reaction at the anode 14 produces positively charged lithium ions and negatively charged electrons. The lithium ions move through the electrolyte 18, and the electrons move through the external circuit (including connection to the electrical load 12 or charging device), and then they recombine at the cathode (together with the cathode material) in the reduction half-reaction.

[0064] The electrolyte 18, current collector (discussed below), and external circuit provide conductive media for lithium ions and electrons, respectively, but do not participate in the electrochemical reactions. Typically, during discharge of an electrochemical battery cell, electrons flow between the electrodes, from the anode 14 to the cathode 16 through the external circuit. The reactions during discharge reduce the chemical potential of the battery, so the discharge transfers energy from the battery to wherever the current consumes its energy, primarily in the external circuit. During charging, the described reactions and transport occur in the opposite direction: electrons move from the positive electrode to the negative electrode through the external circuit. To charge the battery, the external circuit provides electrical energy. This energy is then stored in the battery as chemical energy (with some losses).

[0065] In lithium-ion batteries, both the anode 14 and the cathode 16 allow lithium ions to move in and out of their structures through a process called insertion (embedding) or extraction (de-intercalation), respectively. Typically, the anode 14 uses a current collector, which can be made of copper foil (typically 8-12 microns thick) and includes an active layer using silicon and graphite materials configured to embed lithium ions. During the charging process, lithium combines with silicon, which causes the silicon to expand significantly. Specifically, the silicon anode reacts with lithium through intermetallic alloying, causing the silicon to expand to up to three times its original volume. After a large number of charge-discharge cycles, the expansion of silicon may cause the anode active material to be delaminated from the current collector and thus the decomposition of the negative electrode structure. As a result, the structural integrity and cycle capacity of the lithium-ion battery cell 10 will be negatively affected.

[0066] The specific structure of the anode 14, described below, is configured to minimize the possibility of delamination of the anode active material from the current collector and decomposition of the negative electrode structure during charge / discharge cycles of the battery cell 10. Figure 1 As shown, the anode 14 of the present invention includes an electrode substrate or current collector 24, which can be composed of a section of metal foil (commonly referred to as current collector foil). Typically, the current collector is independently manufactured by rolling or by electrodeposition, such as aluminum foil for cathodes and copper foil for anodes. The current collector 24 can be composed or composed of copper.

[0067] The anode 14 of the present invention also includes an active layer 26 disposed on and fixed to the current collector 24. Figure 1 and 2 As shown, the active layer 26 includes a discrete plurality of first material portions 28 and one or more second material portions 30 arranged in an alternating pattern 32. With particular reference to Figure 3, the plurality of first material portions 28 may be graphite or graphite-containing portions, which additionally contain a binder 28-1, active material particles 28-2, and conductive additives, i.e., reinforcing particles 28-3. One or more second material portions 30 may be silicon or silicon-containing portions, which additionally contain a binder 30-1, active material particles 30-2, and conductive enhancing particles 30-3. The amounts and ratios of the binder, active material particles, and conductive enhancing particles may vary between the various first material portions 28 and second material portions 30. Each second material portion 30 may contain pure silicon, silicon alloys, SiO x (Silicon oxide), LiSiO x (lithium silicon oxide) or Si-C (silicon carbon composite).

[0068] The binders 28-1 and 30-1 may be polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), lithium polyacrylate (Li-PAA), sodium polyacrylate (Na-PAA), polytetrafluoroethylene (PTFE), etc., the active material particles 28-2 and 30-2 (graphite, hard carbon, LTO, Si, lithium metal, Sn, etc.), and the conductivity enhancing particles 28-3 and 30-3 may be carbon black, graphene, graphene nanosheets, carbon nanotubes, carbon fibers, etc. The alternating pattern 32 is specifically configured to align each material portion 28, 30 parallel to the current collector 24. Thus, the resulting active layer 26 is configured to store transient ions, such as lithium ions, during charging of the battery cell 10, when, for example, the graphite anode intercalates lithium transient ions into the gaps of its crystalline structure active layer, while the silicon anode material reacts with lithium and releases lithium during charging of the battery cell. The alternating pattern 32 of first material portions 28 and second material portions 30 is intended to limit expansion of the silicon and minimize the likelihood of anode delamination.

[0069] The active layer 26 may be defined by a height H and a length L and a width W (eg, Figure 1 ). The current collector 24 is generally coextensive with the active layer 26 in terms of length L and width W. Figure 1 and Figure 2 , which shows a side view of various embodiments of the active layer 26, one of the first material (e.g., graphite) portions 28 is positioned adjacent to and in direct contact with the current collector 24, thereby ensuring reliable attachment of the active layer during battery cell cycling. Figure 1 As shown, the active layer 26 includes at least three different parts: a second material part 30 sandwiched between two first material parts 28. Alternatively, as shown in FIG. Figure 2As shown, active layer 26 may include a plurality of second material portions 30 such that each second material portion is disposed between and in direct contact with two first material portions 28. Also shown, the top layer of active material layer 26 (near separator 20) is also graphite first material portion 28.

[0070] As in Figure 1 and Figure 2 As can be seen in each of the FIG. 1 , the alternating pattern 32 is produced via a layered structure such that each of the discrete plurality of first material portions 28 and the one or more second material portions 30 spans each of the length L and width W of the current collector 24. The active material portions 28, 30 may be applied as a coating to the active layer 26 or otherwise deposited thereon such that the active material portions are arranged in an alternating pattern 32 on the active layer. For example, as Figure 4 As shown, the active layer 26 can be generated by separate 3D dry printing or co-extrusion printing of the corresponding first material portion 28 and second material portion 30. In another embodiment, as Figure 5 As shown, the active layer 26 can be generated by applying a separate slurry of each corresponding first material portion 28 and second material portion 30 onto the current collector 24. Alternatively, in a third embodiment, as shown in FIG. Figure 6 As shown, active layer 26 may be generated by simultaneously slurry coating first material portion 28 and second material portion 30 onto current collector 24 .

[0071] As a result, charging of the battery cell 10 employing the anode 14 of the present invention reversibly deposits transient ions (e.g., lithium ions) onto each active material portion 28, 30. During charging of the battery cell 10, the active material portion 28 constrains expansion of the active material portion 30, thereby maintaining the structural integrity of the active material current collector. During discharging of the battery cell 10 employing the anode 14 of the present invention, the transient ions are extracted from the active material portions 28, 30. Thus, the battery cell 10 may undergo repeated cycles of intercalation and deintercalation of lithium ions while accepting charge from an external energy source, such as a power grid, and then providing charge to power the load 12.

[0072] Figure 7 A method 100 for making an anode 14 for a rechargeable battery cell 10 is depicted in and disclosed in detail below. The method 100 is generally directed to producing an active layer structure 26 on a current collector 24, as described above with reference to Figure 1-6The method 100 begins in frame 102 by providing a current collector 24, for example by placing the current collector on an appropriate assembly or process fixture. After frame 102, the method proceeds to frame 104. In frame 104, the method includes depositing an active layer 26 having a discrete plurality of first material portions 28 and at least one second material portion 30 onto the current collector 24. In frame 104, the method also includes arranging the first material portions 28 and the second material portions 30 in an alternating pattern 32, and aligning each material portion parallel to the current collector 24 to produce the anode 14.

[0073] In box 104, the method may also include placing one of the plurality of first material portions 28 adjacent to and in direct contact with the current collector 24. Additionally, in embodiments where the active layer 26 has a plurality of second material portions 30, in box 104, the method may include arranging each second material portion between and in direct contact with two first material portions 28. The alternating pattern 32 may be defined by a layered structure, as described above with reference to Figure 1 and Figure 2 As described, each of the discrete plurality of first material portions 28 and one or more second material portions 30 spans each of the length L and width W of the current collector 24. In block 104, the method may also deposit the active layer 26 on the current collector 24 by 3D printing or co-extrusion printing the corresponding first material portion 28 and second material portion 30 onto the current collector, such as Figure 4 shown.

[0074] Specifically, 3D printing of the corresponding first material portion 28 and second material portion 30 can be performed by separate devices 34, 36, 38 (e.g. Figure 4 Alternatively, it can be done by a separate nozzle (which can also be Figure 4 The active layer 26 can be deposited on the current collector 24 by applying the first material portion 28 and the second material portion 30 slurry to the current collector, as shown in the figure. Figure 5 and Figure 6 As shown. Figure 5 As shown, the first material portion 28 and the second material portion 30 may be deposited separately and sequentially by introducing the respective material slurries via respective coating dies / nozzles 40 and spreading the slurries onto the current collector 24 via coating rollers 42. Alternatively, as shown Figure 6 As shown, the first material portion 28 and the second material portion 30 slurries may be deposited onto the current collector 24 by passing through a multi-die nozzle 44 and spreading the combined slurries onto the current collector 24 by a coating roller 42 .

[0075] As about Figure 1-4 As described, the discrete first material portion 28 of the active layer 26 may include graphite, a binder 28-1, active material particles 28-2, and conductivity enhancing particles 28-3. In addition, the discrete second material portion 30 may include silicon, a binder 30-1, active material particles 30-2, and conductivity enhancing particles 30-3. After generating the active layer 26, the method may proceed from frame 104 to frame 106. In frame 106, the method includes drying the anode 14, for example in an oven, to cure the graphite, the binder 28-1, the active material particles 28-2, and the conductivity enhancing particles 28-3. After frame 106, the method may end at frame 108, or continue to incorporate the completed anode 14 into the battery cell 10 in frame 110.

[0076] When the resulting anode 14 is used in a battery cell 10, charging of the battery cell reversibly intercalates transient ions into the first material portion 28 and the second material portion 30. The alternating pattern 32 of the active layer 26 limits expansion or swelling of the second, e.g., silicon material portion 30, which is bounded by the adjacent first material portion 28. Conversely, discharging of the battery cell 10 extracts transient ions from the first material portion 28 and the second material portion 30. The active layer 26 having the alternating pattern 32 produced by the method 100 is intended to promote an increase in the number of charge-discharge cycles in the battery cell 10 by minimizing the possibility of delamination of the anode active material from the current collector and decomposition of the negative electrode structure. As a result, the structural integrity and cycling capacity of the host battery cell 10 are enhanced.

[0077] The detailed description and the accompanying drawings or figures are support and description of the present disclosure, but the scope of the present disclosure is limited only by the claims. Although some best modes and other embodiments for carrying out the claimed disclosure have been described in detail, there are various alternative designs and embodiments for practicing the disclosure defined in the appended claims. In addition, the features of the embodiments shown in the drawings or the various embodiments mentioned in this specification do not necessarily have to be understood as embodiments independent of each other. On the contrary, each feature described in one of the examples of the embodiment can be combined with one or more other desired features from other embodiments to obtain other embodiments that are not described in words or with reference to the drawings. Therefore, such other embodiments fall within the framework of the scope of the appended claims.

Claims

1. An anode for a rechargeable battery cell, comprising: Electrode substrate; a current collector fixed to the electrode substrate; and an active layer disposed on the current collector and having a discrete plurality of first material portions and at least one second material portion arranged in an alternating pattern; in: Each material portion is aligned parallel to the current collector; and The active layer is configured to intercalate transient ions during charging of the battery cell and to deintercalate transient ions during discharging of the battery cell. 2 . The anode of claim 1 , wherein each first material portion comprises graphite and each second material portion comprises silicon.

3. The anode according to claim 2, wherein the second material portion comprises pure silicon, silicon alloy, SiO x (Silicon oxide), LiSiO x One of (lithium silicon oxide) and Si-C (silicon carbon composite). 4 . The anode of claim 1 , wherein one of the plurality of first material portions is positioned adjacent to and in direct contact with a current collector. 5 . The anode of claim 4 , wherein the at least one second material portion comprises a plurality of second material portions, and wherein each second material portion is disposed between and in contact with two first material portions.

6. The anode of claim 4, wherein the current collector is defined by a length and a width, and wherein the alternating pattern is defined by a layered structure such that each of the discrete plurality of first material portions and at least one second material portion spans each of the length and width of the current collector.

7. The anode of claim 1, wherein the first material and the second material each comprise respective conductivity enhancing particles and a polymer binder.

8. The anode of claim 1, wherein the active layer is generated by applying a separate slurry of each corresponding first material portion and second material portion onto a current collector. 9 . The anode of claim 1 , wherein the active layer is generated by simultaneously slurry-coating the first material portion and the second material portion onto a current collector.

10. The anode of claim 1, wherein the active layer is generated by one of 3D printing and co-extrusion printing of the respective first material portion and the second material portion.

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