Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/66—Selection of materials
  • H01M4/661—Metal or alloys, e.g. alloy coatings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/66—Selection of materials
  • H01M4/663—Selection of materials containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/70—Carriers or collectors characterised by shape or form
  • H01M4/80—Porous plates, e.g. sintered carriers
  • H01M4/808—Foamed, spongy materials
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present inventions generally relates to lithium ion batteries and methods of manufacturing same.
• Lithium ion battery electrodes are generally produced using a slurry (or paste).
• This slurry generally includes an electrode active material, a binder material, and an electrical conductive additive material all dispersed in a solvent (such as NMP).
• This slurry is coated onto both surfaces of a thin metallic current collector foil (typically between 30 and 100 micrometers thick).
• the current collector is copper for the negative electrode and aluminum for the positive electrode.
• This process also requires that an entire section (or sections) of the current collector foil to be left uncoated. Subsequent to the electrode coating and calendaring, at least one tab (per electrode) is welded to the current collector foil within the uncoated area. This tab is necessary to make and secure electrical contact between the electrodes and the terminals in the cell packaging material or housing (e.g., a cylindrical can, a soft prismatic pouch or a hard prismatic can). [0007] In addition, the tab may need to be welded to the packaging material in order to provide a continuous electrical link between the cell and its housing. This is typically done by electrically welding the anode tab to the bottom of the steel can, in an 18650 format, or by laser welding the cathode tab to the CID/Cap plate.
• the cell packaging material or housing e.g., a cylindrical can, a soft prismatic pouch or a hard prismatic can.
• the present invention seeks to provide a battery cell that improves on the prior designs, as well as a providing a more efficient method of making the battery.
• the invention relates to a process for the production of lithium ion battery electrodes that have high electrical conductivity, and which provides an easier method of production, and which provides a construction for the electrode in which the average maximum distance between an active material particle and a metallic current collector point is less then 100 microns—preferably less then approximately 50 microns.
• a thicker electrode can be produced, without compromising its performance, and, thus enabling the fabrication of a cell with improved energy and power density at a lower cost.
• Some embodiments of the present invention utilize a 3-dimensionally electrically conducting porous current collector material, filled with a paste-like electrode material composition and compressed after being filled by the electrode material.
• the porous current collector material is open celled porous metallic foam.
• Such a current collector material has a high electrical conductivity and will result in a maximum distance between active material particle and current collector of 100 microns or less.
• the open celled porous metallic foam includes nickel when used in association with the negative electrode and aluminum or graphite/carbon when used in association with the positive electrode. These foams may be approximately (i.e., +/-10%) 3 to 5 mm in thickness and have a porosity in excess of 60% (by volume or weight?),
• the electrodes may be made using a paste containing little, if any, solvent and which is applied to the foam in a manner so as to enable filling of a significant fraction of the foam porosity. Subsequent to pasting the foam with the electrode paste, the electrode-foam is compressed to about one -third to one-fifth of its original thickness. The compressed electrode-foam can be further processed in to a plate, a strip, a ribbon or any other required shapes prior to its final assembly into a battery.
• the AC IR of the resulting battery is less than 5 mOhms/Ah, preferably less then 1 mOhm/Ah based on an equivalent 18650 cylindrical format.
• a typical "energy” cell battery design made according to these known methods has an AC IR value in excess of 20 mOhms/Ah.
• a typical "power” cell battery design according to these known methods has an AC IR value in excess of 10 mOhms/Ah.
• the present invention provides a new cell design that does not include a tab, and therefore does not require tab welding or a tab connection between the electrodes and the terminals.
• This design utilizes a continuous (or non-interrupted) electrode coating process for the production of electrodes.
• such electrodes do not require any further material removal, cleaning, or scratching as required with prior art designs and methods of manufacture. Further, such electrodes have lower calendaring defects and can be process faster which increases production yield.
• Embodiments of the present invention may include offset electrode alignment, which results in a tab-less construction for the production of a low AC IR lithium ion battery.
• This composite structured pad allows for the pad to be maintained under compression, thus securing electrical continuity, while preventing the metallic 3D structure from breaking, losing electrical continuity, or losing contact due to permanent or non-reversible compression.
• a preferred embodiment of the invention includes a negative electrode made with a full width coated electrode and a positive electrode made out of an electrode that has one edge uncoated. This uncoated edge is useful to prevent local capacity unbalance and to prevent lithium metal deposition on the opposite surface of the negative electrode.
• Embodiments of the present invention allow for a method to accurately and reliably cut or trim the uncoated excess edge aluminum foil.
• this foil can be very thin, approximately 10 micrometers (compared to approximately 20 micrometers for some conventional battery cells), and as such can be difficult to cut/trim accurately using traditional rotary knife slitting equipment. Therefore, some embodiments allow for the use of a low power laser to cut the uncoated aluminum excess.
• Certain embodiments of the present invention provide low resistance and continuous electrical contact between the edges of a cell (jelly roll or prismatic) and its packaging material (can or soft pouch) by utilizing a porous and compressible electrically conducting foam (nickel, aluminum and/or carbon are preferred) to make the electrical connections.
• a porous and compressible electrically conducting foam nickel, aluminum and/or carbon are preferred
• the porous compressible electrically conducting foam is filled with an elastomeric material in order to allow this component to reversibly deform to best adapt to the jelly roll dimension variations.
• Such a cell may have a low AC IR, and will increase performance because of the lack of any tab, tab welding, and because it does not require interrupted coating. Moreover, the fabrication process may have improved yield and improved quality, thus allowing a lower cost. Further, cells assembled using certain embodiments of the present invention may show no variation or degradation of their AC IR value due to mechanical vibration. Further, such cells may have a lower temperature increase at high discharge rates compared with conventional cells assembled using tabs. Finally, such cells may have a more uniformly cut/trim uncoated edge of the positive electrode which will provide a uniform and stable contact with the current collecting conductive foam.
• At least one of its current collectors may be coated with an electrically enhancing primer layer.
• the primer layer is preferably inorganic and basic and lithium polysilicates are one contemplated primer.
• the continuous coating allows for use of the primer and there is no need for overlaying electrode coating registration.
• the use of a primer is a result of the electrode coating onto the metallic substrate being non-interrupted and electrode tab welding not being required.
• the uncoated edge of the electrode is covered with a rubber type material that will flow in between the electrode layer without covering the edges of the electrode. Thus, electrical contact still can be made, while the ends of the electrode may be mechanically reinforced.
• FIG. 1 is a side elevation cut away view of a battery cell according to one or more embodiments of the present invention
• FIG. 2 is a side elevation cut away view of a battery cell according to one or more embodiments of the present invention.
• FIG. 3 is a front perspective view of an embodiment of an electrode used in a battery cell according to one or more embodiments of the present invention
• FIG. 4 is a side elevation view of the electrode of FIG. 3; and, [0030] FIG. 5 is a side elevation view of two electrodes in an offsetting configuration.
• the invention in one embodiment of the invention, relates to lithium ion battery cell 10 having housing 12 with first terminal 14 and second terminal 16.
• First electrode 18 is in electrical communication with first terminal 14 and second electrode 20 is in electrical communication with second terminal 16.
• At least first electrode 18 comprises current collector 22 which is metallic foam 24 having a plurality of open pores 26.
• First electrode 18 also includes electrode material 28. In this manner, a portion of electrode material 28 is disposed within the open pores 26 of the metallic foam 24. If first electrode 18 is an anode, it is contemplated that that the metallic foam 24 includes nickel. Alternatively, if first electrode 18 is a cathode, it is contemplated that the metallic foam 24 includes aluminum and/or carbon.
• the metallic foam 24 have a porosity of at least 60%, and most preferred that the porosity is at least 90%. It is also preferred that in battery cell 10, a maximum distance between electrode material 28 and metallic foam 24 is approximately 100 microns. Moreover, it is preferred that the metallic foam 24 has a thickness of approximately 3 to 5 mm.
• a preferred method of making battery cell 10 includes a step of pasting electrode material 28 onto current collector 22 to form first electrode 18.
• current collector 22 comprises metallic foam 24 which includes a plurality of open pores 26.
• first electrode 18 is compressed such that it has a thickness of between 1/3 and 1/5 of an original thickness. Thereafter, first electrode 18 may be inserted into housing 12.
• first electrode 18 is processed into a desired shape after compressing first electrode 18 and before inserting first electrode 18 into housing 12.
• battery cell 10 and the method of making same provide benefits for the battery based upon the use of the metallic foam. For example, a thicker electrode can be produced, without compromising its performance. Accordingly, an improved battery cell can be made with improved energy and power density at a lower cost.
• the present invention also relates to a battery 50 with a "spiral wound” or “jelly roll” type electrode configuration.
• battery 50 includes housing 52 having first terminal 54 connected to first electrode 56 and a second terminal 58 connected to second electrode 60.
• Metallic foam 62 is used at least to electrically connect first terminal 54 to first electrode 56, and preferably also to connect second terminal 58 to second electrode 60. It is contemplated that the metallic foam 62 includes a compressible material, such as rubber, etc.
• first electrode 56 has the configuration of electrode 100 in FIGS. 3 and 4.
• second electrode 60 has the configuration of electrode 100 (from FIGS. 3 and 4).
• electrode 100 comprises a current collector 102 and an electrode material 104.
• Current collector 102 includes an exposed edge 106 across its length L, and exposed edge 106 is in contact with metallic foam 60. Exposed edge 106 can be either top edge 108 or bottom edge 110 of current collector 102. See, e.g., FIG. 5.
• exposed edge 106 it is meant that there is no electrode material 104 disposed on that portion (the exposed edge 106) of current collector 102. As discussed herein, it is contemplated that current collector 102 include and/or be coated with, primers, rubber material, and other substances to increase its strength and electrical connectivity to the metallic foam 60. Thus, “exposed edge” 106 merely means that there is no electrode material 104 on exposed edge 106, but other substances may be present on exposed edge 106 of current collector 102. [0044] As can be seen in FIGS. 3 and 4, current collector 102 has a height H extending from top edge 108 to bottom edge 110, a length L extending from first edge 112 to second edge 114.
• Electrode material 104 is disposed on at least first side 116 of current collector 102 continuously from first edge 112 to the second edge 114 and from the bottom edge 110 to a distance shorter than the height H, such that exposed edge 106 is formed along the top edge 108 along the length L of the current collector 102.
• exposed edge 64 of first electrode 56 is disposed within metallic foam 62. Further, although not required, exposed edge 66 of second electrode 60 is also disposed in electrical contact within metallic foam 62. In this manner, metallic foam 62 electrically connects each electrode 56, 60, with its respective terminal 54, 58 of battery cell 50.
• both electrodes 100a, 100b used in a battery utilize the construction shown in FIGS. 3 and 4.
• electrodes 100a, 100b will be offset during winding. See, FIG. 5.
• exposed edge 106a of electrode 100a extends downward
• exposed edge 106b of electrode 100b extends upwards.
• the terms upward and downward, as well as top and bottom are used merely for reference, and one could simply rotate the electrode to change top to bottom and still be within the scope of the present invention.
• a battery having such an electrode configuration is believed to beneficial for many reasons. With the elimination of the welding typically required in such batteries, the time and effort needed to make the battery decreases—which in turn decrease the cost. Moreover, the lack of welding results in less opportunity for failure of the battery due to calendaring or other welding mistakes. Further, with a thinner current collector, a low power laser can be used to cut the current collector to the appropriate size or to trim the exposed edge.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Cell Electrode Carriers And Collectors (AREA)
• Secondary Cells (AREA)

Applications Claiming Priority (2)

Publications (1)

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Cited By (2)

Citations (5)

• 2013
  • 2013-02-14 WO PCT/US2013/026046 patent/WO2013123126A1/fr not_active Ceased

Patent Citations (5)

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