Non-rectangular batteries for portable electronic devices

Abstract

Battery cell comprising: a set of layers (102-106, 202, 304-310) forming a non-rectangular shape, wherein the set of layers (102-106, 202, 304-310) comprises a cathode with an active coating, a separator (204, 302) and an anode with an active coating; a pocket (108) enclosing the layers (102-106, 202, 304-310), the pocket (108) being flexible; a first conductive flat connector (110) coupled to the cathode; and a second conductive flat connector (112) coupled to the anode; wherein the first and second conductive flat connectors (112) extend through the seals in the pocket (108) to provide terminals for the battery cell.

Description

BackgroundField of InterestThe present embodiments relate to batteries for portable electronic devices. More specifically, the present embodiments relate to battery cells having non-rectangular shapes to enable efficient use of space within the portable electronic devices.Related ArtRechargeable batteries are currently used to provide power to a wide variety of portable electronic devices including laptop computers, tablet computers, cellular phones, personal digital assistants (PDAs), digital media players, and cordless power tools. The most commonly used type of rechargeable batteries is a lithium battery, which may comprise a lithium ion or a lithium polymer battery.Lithium polymer batteries often comprise cells packed in flexible bags. Such bags are typically light in weight and are inexpensive to produce. Additionally, these pockets may be tailored to different cell sizes, allowing lithium polymer batteries to be used in space-limiting portable electronic devices, such as cellular phones, laptop computers, and / or digital cameras. For example, a lithium polymer battery can achieve a packaging efficiency of 90 to 95% by enclosing rolled electrodes and electrolytes in an aluminum-coated laminated pouch. Multiple pockets may then be placed side-by-side within a portable electronic device and electrically coupled in series and / or in parallel to form a battery for the portable electronic device.However, efficient use of space may be limited by the use and arrangement of cells in existing battery pack architectures (battery pack architecture). In particular, battery packs typically include rectangular cells of the same capacity, size, and dimensions. The physical arrangement of the cells may additionally reflect the electrical configuration of the cells. For example, a six cell battery pack may include six lithium polymer cells of the same size and capacity configured in a two-in-series, three-parallel (2s3p) configuration. Within such a battery pack, two rows of three cells placed side-by-side may be stacked on top of each other; each row may be electrically coupled in a parallel configuration and the two rows may be coupled in a series configuration. Thus, the battery pack may demand space in a portable electronic device that is at least the length of each cell, twice the thickness of each cell, and three times the width of each cell.Moreover, this general type of battery pack design may not be able to use free space in the portable electronic device that is outside of a rectangular space reserved for the battery pack. For example, a rectangular battery pack of this type may not be able to efficiently use free space that is curved, rounded, and / or irregularly shaped.Therefore, the use of the portable electronic devices may be facilitated by improvements related to packaging efficiency, capacity, form factor, design, and / or manufacturing of battery packs including lithium polymer battery cells.US 2011 / 0183183 A1 discloses a stacked arrangement of a plurality of thin film batteries electrically connected to each other, the stacked arrangement being in a staggered configuration, and the outermost points of the side edges on one side of the stacked arrangement corresponding.U.S. Pat. No. 6,224,995 B1 discloses a battery device having a housing, at least two stacked lithium ion cells, an element for maximizing utilization of the housing and an element for excluding unintentional deformation of the housing.US 2007 / 0105014 A1 discloses an electrode assembly having a plurality of unit cells folded by a continuous separator sheet, the unit cells being arranged on the separator sheet so that the electrode pins of the unit cells face each other, the separator sheet having openings corresponding to the electrode pins of the unit cells, and the electrode assembly is manufactured by folding the unit cells in the longitudinal direction of the separator sheet while the unit cells are arranged so that the electrode pins of the unit cells are inserted into the corresponding openings, and an electrochemical cell such as a secondary battery including the same.SummaryThe disclosed embodiments provide a battery cell. The battery cell includes a set of layers forming a non-rectangular shape, the set of layers including a cathode with an active coating, a separator, and an anode with an active coating. The battery cell also includes a first conductive tab coupled to the cathode and a second conductive tab coupled to the anode. The layers are enclosed in a flexible pouch and the first and second conductive tabs are extended through seals in the pouch to provide connections for the battery cells. Furthermore, the non-rectangular shape is created by removing material from one or more of the layers.In some embodiments, removing material from one or more of the layers includes removing the material from one or more sides of the cathode or anode to form the non-rectangular shape. For example, the material may be removed from a corner of the cathode and / or anode to form a rounded corner in the battery cell.In some embodiments, the non-rectangular shape includes two or more thicknesses. For example, the two or more thicknesses may be created by removing material from the bottom and / or side of the cathode and / or anode to allow the battery cell to gradually decrease in thickness from one end to the other.In some embodiments, the set of layers is used to generate at least one of a jellyroll and a bi-cell. For example, the layers may be wound on a mandrel to form a spiral wound jelly roll. Alternatively, the layers may be formed in Bi cells placed on a large sheet of the separator. The separator may then be repeatedly folded in one direction to stack the Bi cells and form the non-rectangular shape.Brief Description of the DrawingsFIG. 1 shows a top-down view of a battery cell according to the disclosed embodiments. FIG. 2 shows a cross-sectional view of a battery cell according to the disclosed embodiments. FIG. 3 shows the arrangement of a set of layers for a battery cell according to the disclosed embodiments. FIG. 4 is a flow chart illustrating the process of manufacturing a battery cell in accordance with the disclosed embodiments. FIG. 5 illustrates a portable electronic device according to the disclosed embodiments.In the figures, like reference numerals refer to the same figure elements.Detailed DescriptionThe following description is presented to enable one skilled in the art to make and use the embodiments and is provided in connection with a particular application and its requirements. Various modifications of the disclosed embodiments will readily be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present disclosure. Thus, the present invention is not limited to the embodiments shown, but is accorded the widest scope consistent with the principles and features disclosed herein.The data structures and code described in this detailed description are typically stored on a computer readable storage medium, which may be any device or medium capable of storing code and / or data for use by a computer system. The computer readable storage medium includes, but is not limited to, volatile memory, nonvolatile memory, magnetic and optical storage devices such as hard disk drives, magnetic tape drives, compact disk (CDs), digital versatile disks (DVDs or digital video disks), or other media capable of storing code and / or data now known or later developed.The methods and processes described in the detailed description section may be embodied as code and / or data that may be stored in a computer readable storage medium as described above. When a computer system reads and executes the code and / or data stored on the computer readable storage medium, the computer system executes the methods and processes embodied as data structures and code and stored within the computer readable storage medium.Furthermore, the methods and processes described herein may be included in hardware modules or devices. These modules or devices may include, but are not limited to, an application specific integrated circuit (ASIC) chip, a field programmable gate array (FPGA), a dedicated or shared processor that executes a particular software module or portion of code at a particular time, and / or other programological devices now known or later developed. When the hardware modules or devices are activated, they perform the methods and processes included within them.The disclosed embodiments relate to the design of a battery cell that includes a set of layers enclosed in a pocket. The layers may comprise a cathode with an active coating, a separator, and an anode with an active coating. The layers may be stacked and / or wound to produce a jet roll and / or bi-cell. The battery cell also includes a first conductive tab coupled to the cathode and a second conductive tab coupled to the anode. The first and second conductive tabs extend through seals in the pocket to provide connections for the battery cell.Additionally, the battery cell may have a non-rectangular shape and / or design. The term "non-rectangular" may mean that the battery cell is rectangular across a cut plane, or in other words, that the battery cell is non-rectangular when viewed from top, bottom, and / or sides.More specifically, the non-rectangular shape may be formed by removing material from one or more of the layers before the layers are wound or stacked. For example, the material may be removed from one or more sides of the anode and / or cathode to form a rounded corner in the battery cell. The removed material may also form two or more thicknesses in the battery cell. The non-rectangular shape may further enable efficient use of the space within a portable electronic device, e.g., by accommodating a corrugated shape of the portable electronic device.FIG. 1 shows a battery cell according to an embodiment. The battery cell may correspond to a lithium polymer cell that provides power to a portable electronic device, such as a laptop computer, a mobile phone, a tablet computer, a personal digital assistant (PDA), a portable media player, a digital camera, and / or other types of battery powered electronic devices.As shown in FIG. 1, the battery cell includes a number of layers 102- 106 forming a non-rectangular terraced structure with a rounded corner. The layers 102- 106 may include a cathode with an active coating, a separator, and an anode with an active coating. For example, each set of layers 102- 106 may include a strip of cathode material (e.g., aluminum foil coated with a lithium compound) and a strip of anode material (e.g., copper foil coated with carbon) separated by a strip of separator material (e.g., conductive polymer electrolyte).To form the non-rectangular shape, material may be removed from the layers 102- 106. For example, material may be removed from the corners of the cathode and / or anode to form the rounded corners in the battery cell. The material may also be removed from the layers 102- 106 to produce multiple thicknesses in the battery cell. For example, the curved terrace shape associated with the layers 102 to 106 may be formed by removing material from the upper right corners of the layers 102, removing material from the upper top and right sides of the layers 104, and removing more material from the top and right sides of the layers 106. In other words, material may be removed from the layers 102- 106 such that the layers 102- 106 have the same shape, but the lowermost layers 102 are the largest, the middle layers 104 are smaller, and the uppermost layers 106 are the smallest.The layers 102- 106 may then be arranged to form the non-rectangular shape. For example, the layers 102-106 may be wound on a mandrel to form a spiral wound structure, such as a jelly roll. Alternatively, the layers 102 to 106 may be formed in Bi cells placed on a large sheet of a separator. The separator may then be repeatedly folded in one direction to stack the Bi cells and form the non-rectangular shape. In other words, the non-rectangular shape of the battery cell may be affected by both removing material from the layers 102- 106 and subsequently winding and / or stacking the layers 102- 106, as discussed in more detail below with reference to FIG. 3.After the layers 102- 106 are formed into the non-rectangular shape, the layers 102- 106 may be enclosed within a pocket 108, and a set of conductive tabs 110- 112 may be extended through the seals in the pocket (e.g., formed using sealing tape) to provide terminals for the battery cells. The conductive tabs 110-112 may be used to electrically couple the battery cell to one or more other battery cells to form a battery pack. For example, the conductive tabs 110 may be coupled to the cathode / cathodes of the layers 102- 106, and the conductive tab 112 may be coupled to the anode / anodes of the layers 102- 106. The conductive tabs 110-112 may be further coupled to other battery cells in series, parallel, or in series and parallel configuration to form the battery pack. The coupled cells may be enclosed in a hard shell to complete the battery pack or the coupled cells may be embedded within the housing of the portable electronic device.To enclose the battery cell in the pocket 108, the layers 102- 106 may be placed on top of a flexible sheet made of aluminum with a polymer film such as polypropylene. Another flexible sheet may then be placed over the top of the layers 102-106, and the two sheets may then be heat sealed and / or folded. Alternatively, the layers 102- 106 may be placed between two sheets of pouch material that are sealed and / or folded on some (e.g., non-terminal) sides. The remaining sides may then be heat sealed and / or folded to enclose the layers 102-106 within the pocket 108.In one or more embodiments, the battery cell of FIG. 1 enables efficient use of space within the portable electronic device. For example, the terraced and / or rounded edges may allow the battery cell to fit within a curved housing of the portable electronic device. The number of layers (e.g., layers 102- 106) may also be increased or decreased to better match the flex of the housing of the portable electronic device. In other words, the battery cell may comprise an asymmetric and / or non-rectangular design that accommodates the shape of the portable electronic device. The battery cell, in turn, may provide greater capacity, packaging efficiency, and / or voltage than the rectangular battery cells in the same portable electronic device.FIG. 2 shows a cross-sectional view of a battery cell according to the disclosed embodiments. More specifically, FIG. 2 shows a cross-sectional view of the battery cell of FIG. 1. As shown in FIG. 2, a set of layers 202 are arranged to produce three different thicknesses in the battery cell, with the thicknesses decreasing from left to right. The variation in thickness may allow the battery cell to fill the free space within a portable electronic device. For example, the battery cell may be configured to occupy a curved and / or beveled area of the space within a mobile phone, laptop computer, tablet computer, portable media player, digital camera, and / or PDA.The battery cell may be formed by stacking and / or winding layers 202 (e.g., cathode, anode, separator) to produce a jelly roll and / or bi-cell, and enclosing layers 202 in a pocket. Additionally, the plurality of thicknesses may be created by removing material from one or more layers 202 prior to winding and / or stacking layers 202. For example, the Bi cells of different sizes may be generated by stacking sheets of the cathode, the anode, and the separator and cutting the Bi cells from the sheets. The Bi cells may then be placed side-by-side on a large sheet of separator 204 that is repeatedly folded in a direction to stack the Bi cells on top of each other and form the battery cell, as discussed below with reference to FIG. 3.FIG. 3 shows the arrangement of a set of layers 304- 310 for a battery cell according to the disclosed embodiments. More specifically, layers 304- 310 may be used to produce the battery cell of FIG. 1. layers 304- 310 may correspond to Bi cells of different sizes used to form a non-rectangular shape in the battery cell. To produce each bi-cell, a sheet of separator may be placed between a sheet of the cathode material and a sheet of the anode material. The outline of the bi-cell (e.g., rectangular with a rounded corner) may then be cut into the sheets to remove material outside the outline from the bi-cell. The layers 304- 310 may then be placed on a large strip of the separator 302, and the battery cell may be created by repeatedly folding the separator 302 from left to right to form a non-rectangular stack of layers 304- 310.First, the left side of the separator 302 is folded on top of the layers 304 to cover both sides of the layers 304 with the separator 302. Next, the separator 302 and the layers 304 are folded over the layers 306 such that the layers 304- 306 are stacked, but are also separated by a layer of the separator 302. The layers 304- 306 and the separator 302 may be folded over the layers 308 such that the layers 308 are added to the stack but separated from adjacent layers 304 in the stack by the separator 302. Finally, layers 304- 308 and separator 302 are folded over layers 310 such that layers 310 are added to the stack but separated from adjacent layers 306 in the stack by separator 302.The layers 304- 310 may also be disposed on the separator 302 to form the non-rectangular terraced shape of the battery cell. As shown in FIG. 3, the layers 304- 310 may be cut and / or oriented such that the rounded corners of the layers 304- 310 alternate between the left and right sides of the adjacent layers 304- 310 on the separator 302. For example, the upper right corners of layers 304 and 308 are rounded, while the upper left corners of layers 306 and 310 are rounded. Such alternation may ensure that the rounded corners of the layers 304 form a single rounded corner in the battery cell after the layers 304- 310 are stacked using the left-to-right folding process described above.Similarly, the left-to-right arrangement of the layers 304- 310 on the separator 302 may allow the terraced shape of FIG. 1 to be formed after the layers 304- 310 are stacked. More specifically, stacking the layers 304- 3 o 6 may form a stack with large layers 304 on one end of the stack and medium-sized layers 306 on the other end of the stack. Folding the layers 304- 306 over the layers 308 may place the layers 308 next to the layers 304, thus increasing the thickness of the large layers in the stack. Finally, folding the layers 304- 308 over the layers 310 may place the layers 310 next to the layers 306, thus forming a stack with the largest layers 304 and 308 on one end of the stack, the second largest layers 306 in the center of the stack, and the smallest layers 310 on the other end of the stack.FIG. 4 is a flow chart illustrating the process of manufacturing a battery cell in accordance with the disclosed embodiments. In one or more embodiments, one or more of the steps may be omitted, repeated, and / or performed in a different order. Accordingly, the specific arrangement of the steps shown in FIG. 4 should not be construed as limiting the scope of the embodiments.First, a set of layers for a battery cell is obtained (operation 402). The layers may comprise a cathode with an active coating, a separator, and an anode with an active coating. Next, material is removed from one or more of the layers to create a non-rectangular shape in the battery cell (operation 404). For example, the material may be removed to create a rounded corner and / or multiple thicknesses in the battery cell.The layers are stacked and / or wound to create a bi-cell and / or jellyroll (operation 406). For example, the layers may be wound on a flat spindle to produce a jelly roll having a flattened shape. On the other hand, the layers may be cut into Bi cells, which are stacked by placing the Bi cells on a long strip of the separator and repeatedly folding the separator in one direction.To assemble the battery cell, a pocket is obtained to accommodate the jelly roll (operation 408). Next, a first conductive tab is coupled to the cathode of the jelly roll (operation 410) and a second conductive tab is coupled to the anode of the jelly roll (operation 412). The first and second conductive tabs are extended through the seals in the pocket to provide connections for the battery cell (operation 414). Finally, the jelly roll is sealed in the pocket (operation 416). For example, the jelly roll may be sealed by spot welding, adhering, and / or applying heat to the seals.The rechargeable battery cell described above may be generally used in any type of electronic device. For example, FIG. 5 shows a portable electronic device 500 that includes a processor 502, memory 504, and a display 508, all of which are powered by a battery 506. The portable electronic device 500 may correspond to a laptop computer, a cellular telephone, PDA, portable media player, digital camera, and / or other type of battery-powered electronic device. The battery 506 may correspond to a battery pack that includes one or more battery cells. Each battery cell may include a set of layers forming a non-rectangular shape. The layers may comprise a cathode with an active coating, a separator, or an anode with an active coating. The non-rectangular shape may be created by removing material from one or more of the layers. For example, a terraced shape with a rounded corner may be created by removing material from one or more sides of the cathode and / or anode. The non-rectangular shape may allow the battery 506 to fit along the perimeter of a cellular phone, tablet computer, and / or laptop computer having a corrugated shape.The foregoing descriptions of the various embodiments have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the present invention to the forms disclosed. Accordingly, many modifications and variations will be apparent to those skilled in the art. In addition, the above disclosure is not intended to limit the present invention.

Claims

A battery cell comprising: a set of layers (102-106, 202, 304-310) forming a non-rectangular shape, the set of layers (102-106, 202, 304-310) including a cathode having an active coating, a separator (204, 302), and an anode having an active coating; a pouch (108) enclosing the layers (102-106, 202, 304-310), the pouch (108) being flexible; a first conductive tab (110) coupled to the cathode; and a second conductive tab (112) coupled to the anode; wherein the first and second conductive tabs (112) extend through the seals in the pouch (108) to provide connections for the battery cell.The battery cell of claim 1, wherein the non-rectangular shape has a rounded corner.The battery cell of claim 1, wherein the non-rectangular shape has two or more thicknesses.The battery cell of claim 1, wherein the set of layers (102-106, 202, 304-310) is configured as a jelly roll.The battery cell of claim 1, wherein the set of layers (102-106, 202, 304-310) is configured as a bi-cell.A method of making a battery cell, comprising: obtaining (402) a set of layers (102-106, 202, 304-310) for the battery cell, the set of layers (102-106, 202, 304-310) comprising a cathode having an active coating, a separator (204, 302), and an anode having an active coating; removing (404) material from one or more of the layers (102-106, 202, 304-310) to create a non-rectangular shape in the battery cell; and coupling (410) a first conductive tab (110) to the cathode; coupling (412) a second conductive tab (112) to the anode; sealing the layers (416) in a pocket (108) to form the battery cell, wherein the pocket (108) is flexible; and extending (414) the first and second conductive tabs (112) through the seals in the pocket (108) to provide terminals for the battery cell.The method of claim 6, further comprising: stacking (406) the layers prior to sealing the layers in the pocket (108) to produce a bi-cell.The method of claim 6, further comprising: winding the layers (102-106, 202, 304-310) prior to sealing the layers (102-106, 202, 304-310) in the pocket (108) to create a jelly roll.The method of claim 6, wherein removing the material from one or more of the layers (102-106, 202, 304-310) comprises: removing (404) the material from one or more sides of the cathode or the anode to form the non-rectangular shape.The method of claim 6, wherein the non-rectangular shape has a rounded corner.The method of claim 6, wherein the non-rectangular shape has two or more thicknesses.A battery pack comprising: a set of cells, each of the cells comprising: a set of layers (102-106, 202, 304-310) forming a non-rectangular shape, the set of layers (102-106, 202, 304-310) comprising a cathode with an active coating, a separator (204, 302), and an anode with an active coating, a pouch (108) enclosing the layers, the pouch (108) being flexible; a first conductive tab (110) coupled to the cathode; and a second conductive tab (112) coupled to the anode; wherein the first and second conductive tabs (110, 112) extend through the seals in the pouch (108) to provide terminals for the battery cell.The battery pack of claim 12, wherein the non-rectangular shape has a rounded corner.The battery pack of claim 12, wherein the non-rectangular shape has two or more thicknesses.The battery pack of claim 12, wherein the set of layers (102-106) is configured as a jelly roll.

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