CURRENT COLLECTOR WITH VENT CHANNELS

A battery includes a positive electrode. The positive electrode includes a first current collector and a first active material. A negative electrode includes a second current collector. The second current collector includes at least one vent channel on at least one surface of the second current collector. The negative electrode includes a second active material.

FIELD

The present disclosure relates generally to the field of lithium batteries or cells.

BACKGROUND

Lithium batteries or cells include one or more positive electrodes, one or more negative electrodes, and an electrolyte provided within a case or housing. Separators made from a porous polymer or other suitable material may also be provided intermediate or between the positive and negative electrodes to prevent direct contact between adjacent electrodes. The positive electrode includes a current collector having an active material provided thereon, and the negative electrode includes a current collector having an active material provided thereon.

SUMMARY

Embodiments described herein involve a battery comprising a positive electrode. The positive electrode comprises a first current collector and a first active material. A negative electrode comprises a second current collector. The second current collector comprises at least one vent channel on at least one surface of the second current collector. The negative electrode comprises a second active material.

Embodiments involve a battery comprising a positive electrode. The positive electrode comprises a first current collector. A negative electrode comprises a second current collector. The second current collector comprises a first planar surface, a second opposing planar surface, and a first vent channel pattern disposed on the first planar surface on at least one surface of the second current collector. A second vent channel pattern is disposed on the second opposing planar surface of the second current collector. The first vent channel pattern is different than the second vent channel pattern.

Embodiments involve a method, comprising providing a current collector having a first planar surface and a second opposing planar surface. A mask is deposited on a portion of at least one of the first planar surface and the second opposing planar surface. An unmasked region is etched to create at least one vent channel.

Advantages and additional features of the subject matter of the present disclosure will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the subject matter of the present disclosure as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description present embodiments of the subject matter of the present disclosure, and are intended to provide an overview or framework for understanding the nature and character of the subject matter of the present disclosure as it is claimed. The accompanying drawings are included to provide a further understanding of the subject matter of the present disclosure and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the subject matter of the present disclosure and together with the description serve to explain the principles and operations of the subject matter of the present disclosure. Additionally, the drawings and descriptions are meant to be merely illustrative and are not intended to limit the scope of the claims in any manner.

DETAILED DESCRIPTION

Reference will now be made in greater detail to various embodiments of the subject matter of the present disclosure, some embodiments of which are illustrated in the accompanying drawings. The figures are not necessarily to scale. Like numbers used in the figures refer to like components and steps. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number. In addition, the use of different numbers to refer to components in different figures is not intended to indicate that the different numbered components cannot be the same or similar to other numbered components.

FIG.1is a diagram of an example electrochemical cell100in accordance with embodiments. The electrochemical cell100includes at least one first electrode102separated from a first side of a second electrode104by a separator106. According to various embodiments, the separator106is a shutdown separator. The first electrode102can comprise a first current collector108substrate having a first active material composite layered thereon. The first current collector108can be substantially planar, or the first current collector108can be curved, although embodiments are not limited thereto. The second electrode104can comprise a second current collector110substrate parallel to the first current collector108substrate. The second current collector110substrate can have a second active material composite layered thereon. The second current collector110can be substantially planar, although embodiments are not limited to planar current collectors. More than one set of electrodes can be included in the electrochemical cell100. For example, current collector110can have active material disposed thereon to form a third electrode112. A second separator114can separate a second side of the second electrode112from a first side of the third electrode116. The third electrode116can be formed by disposing active material on current collector118. WhileFIG.1illustrates a planar cell100embodiments are not limited thereto. Other embodiments include but are not limited to the cell being coiled or rolled up.

The separator106can be resistant to heat distortion. The separator106may be porous such that lithium ions can pass through the separator. The separator106may include a resin or other material that melts or deforms at high temperatures to close pores of the separator106. According to various embodiments, pore shutdown may prevent passage of lithium ions, shutting down the electrochemical cell100current to zero or nearly zero. In some examples, a subset of separators106will shut down.

In some examples, the first electrode102can be a negative electrode and the second electrode104can be a positive electrode. Positive electrodes104can include an active material and a sheet-form current collector (e.g., current collector110) carrying the active material. The positive electrode current collector110, can typically comprise a metal but is not limited thereto. For the positive electrode104,112active material, various materials can be used. The positive electrode104can include a material mixture carried on the current collector110, the material mixture including a positive electrode active material and a small amount of a binder or a conductive material. Positive electrode104active material can include lithium-containing transition metal oxides such as lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide. The binder material can include polytetrafluoroethylene (PTFE) or rubber materials. Negative electrode102can include an active material and a sheet-form current collector108carrying the active material. The negative electrode active material may include one or more of silver vanadium oxide (SVO), carbon monofluoride (CFx), and/or mixtures thereof. The negative electrode current collector108can typically comprise a metal but is not limited thereto. The negative electrode active material can include carbon materials (for example, graphite), a silicon material or silicon alloy, a tin material or a tin alloy, and lithium metal. The lithium metal can include a lithium alloy including metal elements such as aluminum, zinc or magnesium. The negative electrode102binder material can include the same or similar material as used in the positive electrode104binder material.

Current collectors (e.g., current collector108and110) may include current collector tabs (not shown), which are coupled, typically by welding, to respective current collectors and then provided outside the battery cell casing so that the electrochemical cell100energy can be transferred to an external source.

According to various configurations, one or more of the current collectors provided with holes to facilitate adhesion with the respective electrode anode. For example, anode current collectors are provided with holes to facilitate adhesion with the anode.FIG.2illustrates an example of a current collector210having holes230disposed therein in accordance with embodiments described herein. The current collector has a tab220that allows the device to be connected to an external source. The holes may extend all the way through the current collector. In some cases, the holes are configured to extend only partially through the thickness of the current collector.

Current collectors pressed with holes to facilitate adhesions can result in air being entrapped when lithium is pressed on both sides of the collector, for example. In some cases, current collectors without holes can also result in air being entrapped.FIG.3illustrates a current collector310in accordance with embodiments described herein. When the current collector310is pressed onto the electrode335, air325is trapped between the current collector310and the electrode335. This results in the current collector warping315causing the current collector310to have an uneven surface. This uneven surface may cause the current collector310to have poor adhesion to one or both of the lithium layers.

A collector without holes was thought to eliminate this issue, but still there can be pockets of air that get trapped and the adhesion is generally worse when the collector has no holes. Embodiments described herein involve a current collectors having a pattern of holes with vent channels between holes or some holes and with some vent channels eventually reaching the periphery of the collector.FIG.4illustrates an example having a current collector410that has one or more vent channels440disposed on the surface of the current collector in accordance with embodiments described herein. In this example, the current collector is disposed between two layers420,430of electrode material (e.g., lithium).

Titanium anode collectors are generally etched from both sides. To create a hole, the unmasked region is etched from both sides. To create a channel between the holes, on one side only, one side is fully masked and the other is unmasked for the channel. The channel would end up having a depth that is about half the thickness of the collector. This could better ensure that air can leave the holes and reduce the volume of entrapped air.

The vent channels in a current collector can have different patterns. A vent pattern on a first planar side of the current collector may be different than a vent pattern on a second opposing planar side of the current collector.FIG.6Ashows an example of a current collector610having vent channels620,625that extend across the entire surface of the current collector610in accordance with embodiments described herein. The vent channels620,625extend to the periphery of the current collector610allowing air to escape along the direction of arrows630,635. In this example, first vent channels620are disposed on a first planar surface612and second vent channels625are disposed on a second planar surface614. The vent channels620,625may be configured to alternate such that they do not overlap.

FIGS.6B and6Cshow examples of current collectors615,617having one or more vent channels645,647that do not extend across the entire surface of the respective current collector615,617. Specifically,FIG.6Bshows vent channels626disposed on the first planar surface616and vent channels627disposed on the opposing second planar surface618. A single vent channel645that does not extend across the entire first planar surface616is shown. In some cases, more than one vent channel may not extend across the surface as shown in the example ofFIG.6C.

FIGS.7A and7Bshows examples in which the vent channels730,735are all connected on at least one of the first planar surface on the second planar surface in accordance with embodiments described herein. In these examples, the vent channels730disposed on a current collector710,715are connected by a central vent channel720,725that runs along a longitudinal axis of the respective current collector710.

FIGS.8A-8Cshow examples of vent patterns that have one or more vent channels connected at a central region in the center of the current collector in accordance with embodiments described herein.FIG.8Ashows a current collector810having a central vent820disposed on the first planar surface. One or more vents830extend from the central vent820to the periphery of the current collector810. One or more vent channels840indicated by dotted lines may be disposed on the second opposing planar surface of the current collector810. The second opposing planar surface may or may not have a central vent similar to that of the central vent820disposed on the first planar surface.FIG.8Billustrates another example of a current collector812having one or more vents832extending from a central vent822in accordance with embodiments described herein.

FIG.8Cshows another example of a first vent pattern disposed on a first planar surface of a current collector. The first vent pattern includes one or more vent channels834extending from a central vent824. In this example, a second vent pattern844is disposed on the second planar surface of the current collector814. In areas where the first vent pattern and the second vent intersect (e.g.,850), the vent channels may extend through the entire thickness of the current collector814. This may allow additional opportunities for air to escape. In some cases, the first vent pattern and the second vent pattern do not intersect.

FIG.8Dillustrates another example of a current collector816having one or more vent channels836extending from a central vent826. One or more additional vent channels828are disposed along the periphery of the current collector816. The one or more additional vent channels828extend partially through the surface of the current collector.

FIG.9illustrates a process for forming one or more vent channels on a surface of a current collector in accordance with embodiments described herein. A current collector having a first planar surface and a second opposing planar surface is provided910. A mask is deposited920on a portion of at least one of the first planar surface and the second opposing planar surface. The mask creates a masked portion and an unmasked portion. The unmasked portion is etched930to create at least one vent channel.

According to various embodiments, the mask is deposited on a portion of both of the first planar surface and the second opposing planar surface. The at least one vent channel may be configured to prevent air from being trapped between the second current collector and an active material of the negative electrode. The at least one vent channel may be configured to facilitate adhesion between the second current collector and the negative electrode. The at least one vent channel may be configured to reach a periphery of at least one of the first planar surface and the second opposing planar surface. The at least one vent channel may have a depth that is about half a thickness of the current collector.

The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

Example Ex1: A battery comprising: a positive electrode comprising a first current collector and a first active material; a negative electrode comprising: a second current collector comprising at least one vent channel on at least one surface of the second current collector; and a second active material.

Example Ex2: The battery as in example Ex1, wherein the at least one vent channel is configured to prevent air from being trapped between the second current collector and the second active material.

Example Ex3: The battery as in any one of examples Ex1 to Ex2, wherein the negative electrode comprises lithium.

Example Ex4: The battery as in any one of examples Ex1 to Ex3, wherein the at least one vent channel is configured to facilitate adhesion between the second current collector and the negative electrode.

Example Ex5: The battery as in any one of examples Ex1 to Ex4, wherein the second current collector has a first planar surface and a second opposing planar surface and at least one first vent channel is configured to be disposed on the first planar surface and at least one second vent channel is configured to be disposed on the second opposing planar surface.

Example Ex6: The battery of example Ex5, further comprising, wherein the at least one first vent channel and the at least one second vent channel intersect at one or more points

Example Ex7: The battery of example Ex5, wherein the at least one first vent channel and the at least one second vent channel do not intersect.

Example Ex8: The battery as in any one of examples Ex1 to Ex7, wherein the at least one vent channel is configured to reach a periphery of the at least one surface of the second current collector.

Example Ex9: The battery as in any one of examples Ex1 to Ex8, wherein the at least one vent channel has a depth that is about half a thickness of the second current collector.

Example Ex10: The battery as in any one of examples Ex1 to Ex9, wherein the at least one vent channel comprises a channel pattern comprising a plurality of channels that connect at a central location on the at least one surface.

Example Ex11: A battery comprising: a positive electrode comprising a first current collector; a negative electrode comprising: a second current collector comprising: a first planar surface; a second opposing planar surface; a first vent channel pattern disposed on the first planar surface on at least one surface of the second current collector; and a second vent channel pattern disposed on the second opposing planar surface of the second current collector, the first vent channel pattern being different than the second vent channel pattern.

Example Ex12: The battery as in example Ex11, wherein at least one of the first vent channel pattern and the second vent channel pattern is configured to prevent air from being trapped between the second current collector and an active material.

Example Ex13: The battery as in any one of examples Ex11 to Ex12, wherein the negative electrode comprises lithium.

Example Ex14: The battery as in any one of examples Ex11 to Ex13, wherein at least one of the first vent channel pattern and the second vent channel pattern is configured to facilitate adhesion between the second current collector and an active material.

Example Ex15: A method, comprising: providing a current collector having a first planar surface and a second opposing planar surface; depositing a mask on a portion of at least one of the first planar surface and the second opposing planar surface; and etching an unmasked region to create at least one vent channel.

Example Ex16: The method as in example Ex15, further comprising depositing a mask on a portion of both of the first planar surface and the second opposing planar surface.

Example Ex17: The method as in any one of examples Ex15 to Ex16, wherein the at least one vent channel is configured to prevent air from being trapped between the current collector and an active material.

Example Ex18: The method as in any one of examples Ex15 to Ex17, wherein the at least one vent channel is configured to facilitate adhesion between the current collector and an active material.

Example Ex19: The method as in any one of examples Ex15 to Ex18, wherein the at least one vent channel is configured to reach a periphery of at least one of the first planar surface and the second opposing planar surface.

Example Ex20: The method as in any one of examples Ex15 to Ex19, wherein the at least one vent channel has a depth that is about half a thickness of the current collector.

As used herein, singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. The term “and/or” means one or all of the listed elements or a combination of any two or more of the listed elements.

Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred. Any recited single or multiple feature or aspect in any one claim can be combined or permuted with any other recited feature or aspect in any other claim or claims.