Patent Application
20140050955
1. Field
The disclosed embodiments relate to batteries for portable electronic devices. More specifically, the present embodiments relate to battery cells that include mechanical support structures within the battery-cell pouches.
2. Related Art
Portable electronic devices, such as laptop computers, portable media players, and/or cellular telephones, typically operate using a rechargeable battery. Rechargeable batteries for portable electronic devices often include lithium-polymer batteries, which contain cells packaged in flexible pouches. Such pouches are typically lightweight and inexpensive to manufacture. Moreover, these pouches may be tailored to various cell dimensions, allowing lithium-polymer batteries to be used in space-constrained portable electronic devices such as cellular telephones, laptop computers, and/or digital cameras. For example, a lithium-polymer battery cell may achieve a packaging efficiency of 90-95% by enclosing rolled electrodes and electrolyte (which is sometimes referred to as a ‘jelly roll’) in an aluminized laminated pouch. Multiple pouches 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.
In order to efficiently use the space in portable electronic devices, some existing rechargeable batteries do not include an external housings or battery-cell enclosures to protect the battery cells. Instead the battery cells and enclosing pouches may be directly attached to the structures within portable electronic devices. While this design choice can maximize the available energy volume, the battery cells in these rechargeable batteries are often subject to more mechanical stress and potential damage due to battery-cell deformation, for example, when the battery cells are handled during manufacturing. Damaged battery cells can significantly degrade the operating life of rechargeable batteries.
The described embodiments relate to the design of a package for a battery cell. This battery cell includes a jelly roll with layers that are wound together, including a cathode with an active coating, a separator, and an anode with an active coating. Moreover, a pouch encloses the battery cell. Furthermore, a mechanical support structure, within the pouch, surrounds a portion of an outer surface of the jelly roll.
For example, the outer surface of the jelly roll may include ends and a central region, and the portion of the outer surface surrounded by the mechanical support structure may include the central region and/or the ends. In particular, the portion of the outer surface surrounded by the mechanical support structure may include corners of the jelly roll.
Note that the mechanical support structure may comprise a plastic material.
In some embodiments, the pouch includes a first cup in a flexible sheet of pouch material and a second cup in the flexible sheet. The pouch may be formed by folding the second cup over the first cup. Moreover, the pouch may include a layer of aluminum and a layer of polypropylene.
Another embodiment provides an electronic device that includes a set of components powered by a battery pack that includes the battery cell.
Another embodiment provides a method for manufacturing the battery cell. During the method, the mechanical support structure is positioned over the jelly roll so that the mechanical support structure surrounds the portion of the outer surface of the jelly roll, wherein the jelly roll includes layers that are wound together, including the cathode with the active coating, the separator, and the anode with the active coating. Then, the jelly roll and the mechanical support structure are enclosed within the pouch.
In some embodiments, enclosing the jelly roll and the mechanical support structure involves: obtaining a flexible sheet of pouch material; forming a first cup and a second cup in the flexible sheet; creating the pouch to accommodate the jelly roll and the mechanical support structure by folding the second cup over the first cup; and forming the seal by sealing the jelly roll and the mechanical support structure in the pouch along a rim of the first and second cups.
Additionally, the method may involve: coupling a first conductive tab to the cathode of the jelly roll; coupling a second conductive tab to the anode of the jelly roll; and extending the first and second conductive tabs through the seal to provide terminals for the battery cell.
Note that like reference numerals refer to corresponding parts throughout the drawings. Moreover, multiple instances of the same part are designated by a common prefix separated from an instance number by a dash.
Referring back to
Jelly roll 102 also includes a set of conductive tabs 106 coupled to the cathode and the anode. Conductive tabs 106 may extend through seals in the pouch (for example, formed using sealing tape 104) to provide terminals for battery cell 100. Conductive tabs 106 may then be used to electrically couple battery cell 100 with one or more other battery cells to form a battery pack. For example, the battery pack may be formed by coupling the battery cells in a series, parallel, or series-and-parallel configuration. As described further below with reference to
Note that the battery pack may be constructed without external battery-cell enclosures, such as one or more external mechanical housing (outside of the pouch) that encloses the battery cell(s). However, in order to provide mechanical support and protection, battery cell 100 may also include mechanical support structure 114, within the pouch, which surrounds a portion of an outer surface of jelly roll 102. For example,
As noted previously, battery cell 100 may be included in a battery pack. This battery pack may include or may be electrically coupled to a battery management unit (BMU) that manages use of the battery pack in a portable electronic device such as a mobile phone, PDA, laptop computer, tablet computer, portable media player, digital camera, and/or other type of battery-powered electronic device. For example, the BMU may correspond to an integrated circuit that obtains measurements of voltage, current, temperature, and/or other parameters associated with battery cell 100. The BMU may use the measurements to assess the state of charge, capacity, and/or health of battery cell 100. The BMU may also adjust the charging and/or discharging of battery cell 100 based on the assessed state of charge, capacity, and/or health. Alternatively, battery cell 100 may be electrically coupled by a bus bar and/or another electrical component to a BMU and/or to other battery cells in the battery pack.
In one or more embodiments, cups 402-404 are formed by punching a first indentation corresponding to the cup 402 in pouch material 400 and punching a second indentation corresponding to cup 404 in pouch material 400. For example, a shallow die may be used to form cup 402, and a deeper die may be used to form cup 402. Cup 404 may then be folded over cup 402, and seal 108 (
Consequently, cup 402 may correspond to the bottom of battery cell 100 (
In an exemplary embodiment, when an external battery-cell enclosure is excluded, the battery cell can be easily deformed by an external force. In order to maintain mechanical integrity from mechanical abuse by a user or an external force during the battery-cell-handling process, the mechanical support structure with the pouch may be included.
As shown in
The mechanical support structure at the top and bottom of the jelly roll can disperse external forces, thereby maintaining good alignment of the electrodes. By protecting the lithium-polymer battery cell from external forces, the external battery-cell housing can be safely removed, which may allow the energy volume to be maximized without compromising run-time or reliability.
The battery cell may be manufactured in a way that facilitates efficient use of space within a portable electronic device while providing mechanical support, as well as protection from vibration and mechanical shock. More specifically,
In some embodiments, enclosing the jelly roll and the mechanical support structure involves: obtaining a flexible sheet of pouch material; forming a first cup and a second cup in the flexible sheet; creating the pouch to accommodate the jelly roll and the mechanical support structure by folding the second cup over the first cup; and forming the seal by sealing the jelly roll and the mechanical support structure in the pouch along a rim of the first and second cups.
Additionally, the method may involve: coupling a first conductive tab to the cathode of the jelly roll; coupling a second conductive tab to the anode of the jelly roll; and extending the first and second conductive tabs through the seal to provide terminals for the battery cell.
In some embodiments of method 600, there may be additional or fewer operations. Moreover, the order of the operations may be changed, and/or two or more operations may be combined into a single operation.
Memory 704 includes one or more devices for storing data and/or instructions for processor 702. For example, memory 704 can include dynamic random access memory (DRAM), static random access memory (SRAM), and/or other types of memory. In some embodiments, instructions for processor 702 in memory 704 include: one or more program modules or sets of instructions, which may be executed by processor 702. Note that the one or more computer programs may constitute a computer-program mechanism. Moreover, instructions in the various modules in memory 704 may be implemented in: a high-level procedural language, an object-oriented programming language, and/or in an assembly or machine language. Furthermore, the programming language may be compiled or interpreted, e.g., configurable or configured, to be executed by processor 702.
In addition, memory 704 can include mechanisms for controlling access to the memory. In some embodiments, memory 704 includes a memory hierarchy that comprises one or more caches coupled to a memory in portable electronic device 700. In some of these embodiments, one or more of the caches is located in processor 702.
In some embodiments, memory 704 is coupled to one or more high-capacity mass-storage devices (not shown). For example, memory 704 can be coupled to a magnetic or optical drive, a solid-state drive, or another type of mass-storage device. In these embodiments, memory 704 can be used by portable electronic device 700 as fast-access storage for often-used data, while the mass-storage device is used to store less frequently used data.
While not shown in
The communication subsystem can include processors, controllers, radios/antennas, sockets/plugs, and/or other devices used for coupling to, communicating on, and handling data and events for each supported networking system. Moreover, in some embodiments a ‘network’ between electronic devices does not yet exist. Therefore, portable electronic device 700 may use the mechanisms in the communication subsystem for performing simple wireless communication between electronic devices, e.g., transmitting advertising frames and/or scanning for advertising frames transmitted by other electronic devices.
Within portable electronic device 700, components may be coupled together using a bus and may be powered by a power source, such as battery 706. The bus may include an electrical, optical, and/or electro-optical connection that the subsystems and components can use to communicate commands and data among one another.
Furthermore, in the preceding embodiments, components are shown directly connected to one another or are shown connected via intermediate components. In each instance the method of interconnection, or ‘coupling,’ establishes some desired communication between two or more circuit nodes, or terminals. Such coupling may often be accomplished using a number of circuit configurations, as will be understood by those of skill in the art; for example, AC coupling and/or DC coupling may be used.
In some embodiments, portable electronic device 700 includes a display 708 for displaying information, such as a liquid-crystal display, a touchscreen, etc.
Portable electronic device 700 can be (or can be included in) any electronic device with at least one communication subsystem. For example, portable electronic device 700 can be (or can be included in): a laptop computer, a media player (such as an MP3 player), an appliance, a peripheral device (such as a trackpad, a touchscreen, a display, a mouse, a camera, a keyboard, a user-interface device, etc.), a subnotebook/netbook, a tablet computer, a smartphone, a cellular telephone, a piece of testing equipment, a network appliance, a set-top box, a personal digital assistant (PDA), a toy, a controller, a digital signal processor, a game console, a computational engine within an appliance, a consumer-electronic device, a portable computing device, a personal organizer, and/or another battery-powered electronic device.
Note that battery 706 may correspond to a battery pack that includes one or more battery cells. Each battery cell may include a jelly roll sealed in a pouch. The battery pack may also include or may be electrically coupled to a BMU.
Although specific components are used to describe portable electronic device 700, in alternative embodiments, different components and/or subsystems may be present in portable electronic device 700. For example, portable electronic device 700 may include one or more additional processors, memory, and/or displays. Additionally, one or more of the subsystems or components may not be present in portable electronic device 700. Moreover, in some embodiments, portable electronic device 700 may include one or more additional subsystems that are not shown in
Moreover, the circuits and components in portable electronic device 700 may be implemented using any combination of analog and/or digital circuitry, including: bipolar, PMOS and/or NMOS gates or transistors. Furthermore, signals in these embodiments may include digital signals that have approximately discrete values and/or analog signals that have continuous values. Additionally, components and circuits may be single-ended or differential, and power supplies may be unipolar or bipolar.
Note that an output of a process for designing an integrated circuit, or a portion of an integrated circuit, comprising one or more of the circuits described herein may be a computer-readable medium such as, for example, a magnetic tape or an optical or magnetic disk. The computer-readable medium may be encoded with data structures or other information describing circuitry that may be physically instantiated as an integrated circuit or portion of an integrated circuit. Although various formats may be used for such encoding, these data structures are commonly written in: Caltech Intermediate Format (CIF), CalmaGDS II Stream Format (GDSII) or Electronic Design Interchange Format (EDIF). Those of skill in the art of integrated circuit design can develop such data structures from schematics of the type detailed above and the corresponding descriptions and encode the data structures on a computer-readable medium. Those of skill in the art of integrated circuit fabrication can use such encoded data to fabricate integrated circuits comprising one or more of the circuits described herein.
In the preceding description, we refer to ‘some embodiments.’ Note that ‘some embodiments’ describes a subset of all of the possible embodiments, but does not always specify the same subset of embodiments.
The foregoing description is intended to enable any person skilled in the art to make and use the disclosure, and is provided in the context of a particular application and its requirements. Moreover, the foregoing descriptions of embodiments of the present disclosure have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the present disclosure to the forms disclosed. Accordingly, many modifications and variations will be apparent to practitioners 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. Additionally, the discussion of the preceding embodiments is not intended to limit the present disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application Ser. No. 61/683,464, entitled “Mechanical Support Structure in a Battery Pouch,” by Richard M. Mank, Taisup Hwang, and Bookeun Oh, Attorney docket number APL-P16905USP1, filed on Aug. 15, 2012, the contents of which is herein incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61683464 | Aug 2012 | US |
