Patent Description:
As digital technologies have developed, electronic devices have been provided in various forms such as smartphones, tablet personal computers (PCs), or personal digital assistants (PDAs). The electronic devices have been developed to be portable or wearable by users, thereby improving portability and accessibility of the users. Typically, a portable or wearable electronic device includes a battery for supplying electric power. Recent electronic devices have employed integral batteries for slimness rather than replaceable batteries. The performance (e.g., the output) of an integral battery may be different according to a configuration scheme of the electrode tabs. Accordingly, in order to maximize battery performance, the configuration scheme of the electrode tabs connected to a cathode and an anode may be an important factor. The <CIT> discloses a battery cell including a plurality of regularly protruding tabs respectively for anode and cathode, which overlap each other so as to be parallel to each other and are coupled to unit lead tabs. The <CIT> discloses a battery pack with pouch cells, wherein each pouch cell has a castellated tab to contact a bus bar for interconnecting different cells. Disclosure of Invention.

Recent electronic devices have required batteries of higher capacity and higher output in order to support high performance modules (or electronic circuits) therein, such as for <NUM>th generation (<NUM>) networks. In order to provide high capacity and high output, batteries have been designed to have relatively lower resistances by using a plurality of electrode tabs. However, a battery having a plurality of electrode tabs may increase the thickness of a battery cell as the plurality of electrode tabs overlap each other in the interior of the battery cell. An increase in the thickness of the battery cell may also increase the thickness of the electronic device. Further, when a thicker electronic device is not desired, the thickness of the battery cell cannot be increased, thus limiting the capacity of the battery.

As another example, a battery having a plurality of electrode tabs may be configured such that the electrode tabs are disposed in the interior of the battery cell such that they do not overlap each other and the electrode tabs exposed to the outside are coupled to each other as a single body. However, because the electrode tabs do not overlap each other, the coupling strength of the electrode tabs may be relatively weak. For example, the electrode tabs may be separated from each other due to an external impact, such as dropping the electronic device.

Accordingly, an aspect of the disclosure is to provide an electrode tab structure in which some areas of a plurality of electrode tabs located in the interior of a battery cell do not overlap each other and which can improve a coupling strength of other areas of the electrode tabs exposed to the outside.

In accordance with the invention, a battery is provided according to claim <NUM>.

In accordance with another aspect of the disclosure, an electronic device is provided according to claim <NUM>.

According to the above-described embodiments, an increase in the thickness of the battery can be minimized by disposing the electrode tabs in the interior of the battery cell such that the electrode tabs do not overlap each other. Additionally, a battery of high capacity can be provided by securing a mounting space for a battery cell. Further, the electrode tabs can be prevented from being separated due to an external impact, such as a drop, by improving a coupling strength of the electrode tabs, thereby reinforcing battery safety.

Hereinafter, various embodiments will be described with reference to the accompanying drawings. Although the disclosure provides specific embodiments illustrated in the drawings and described in detail with reference thereto, the disclosure is not limited to these specific embodiments. Therefore, it should be apparent to those skilled in the art that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the disclosure. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

<FIG> illustrates an electronic device in a network environment according to an embodiment.

Referring to <FIG>, an electronic device <NUM> in a network environment <NUM> may communicate with an electronic device <NUM> via a first network <NUM> (e.g., a short-range wireless communication network), or an electronic device <NUM> or a server <NUM> via a second network <NUM> (e.g., a long-range wireless communication network). The electronic device <NUM> may communicate with the electronic device <NUM> via the server <NUM>. The electronic device <NUM> may include a processor <NUM>, memory <NUM>, an input device <NUM>, a sound output device <NUM>, a display device <NUM>, an audio module <NUM>, a sensor module <NUM>, an interface <NUM>, a haptic module <NUM>, a camera module <NUM>, a power management module <NUM>, a battery <NUM>, a communication module <NUM>, a subscriber identification module (SIM) <NUM>, and an antenna module <NUM>. Alternatively, at least one of the components (e.g., the display device <NUM> or the camera module <NUM>) may be omitted from the electronic device <NUM>, or one or more other components may be added in the electronic device <NUM>. Additionally, some of the components may be implemented as single integrated circuitry. For example, the sensor module <NUM> (e.g., a fingerprint sensor, an iris sensor, or an illuminance sensor) may be embedded in the display device <NUM> (e.g., a display).

The processor <NUM> may execute software (e.g., a program <NUM>) to control at least one other component (e.g., a hardware or software component) of the electronic device <NUM> coupled with the processor <NUM>, and may perform various data processing or computation.

The various data may include software (e.g., the program <NUM>) and input data or output data for a command related thereto. The memory <NUM> may include the volatile memory <NUM> and the non-volatile memory <NUM>.

The program <NUM> may be stored in the memory <NUM> as software, and include an operating system (OS) <NUM>, middleware <NUM>, or an application <NUM>.

The input device <NUM> may include a microphone, a mouse, a keyboard, or a digital pen (e.g., a stylus pen).

The sound output device <NUM> may include a speaker and/or a receiver. The receiver may be implemented separate from, or as part of the speaker.

The display device <NUM> may include a display, a hologram device, or a projector and control circuitry to control a corresponding one of the display, hologram device, and projector.

The sensor module <NUM> may include a gesture sensor, a gyro sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor.

The interface <NUM> may include a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, a secure digital (SD) card interface, or an audio interface.

The connecting terminal <NUM> may include an HDMI connector, a USB connector, an SD card connector, or an audio connector (e.g., a headphone connector).

The power management module <NUM> may be implemented as at least part of a power management integrated circuit (PMIC).

The battery <NUM> may include a primary cell which is not rechargeable, a secondary cell which is rechargeable, and/or a fuel cell.

The communication module <NUM> may include one or more communication processors that are operable independently from the processor <NUM> (e.g., the AP) and supports a direct (e.g., wired) communication or a wireless communication. The communication module <NUM> may include a wireless communication module <NUM> (e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module <NUM> (e.g., a local area network (LAN) communication module or a power line communication (PLC) module). The wireless communication module <NUM> may identify and authenticate the electronic device <NUM> in a communication network, such as the first network <NUM> or the second network <NUM>, using subscriber information (e.g., an international mobile subscriber identity (IMSI)) stored in the SIM <NUM>.

The antenna module <NUM> may include an antenna including a radiating element composed of a conductive material or a conductive pattern formed in or on a substrate (e.g., a printed circuit board (PCB)). The antenna module <NUM> may include a plurality of antennas. Another component (e.g., a radio frequency integrated circuit (RFIC)), other than the radiating element, may be additionally formed as part of the antenna module <NUM>. At least some of the above-described components may be coupled mutually and communicate signals (e.g., commands or data) therebetween via an inter-peripheral communication scheme (e.g., a bus, general purpose input and output (GPIO), a serial peripheral interface (SPI), or a mobile industry processor interface (MIPI)).

<FIG> illustrates an electronic device according to an embodiment.

Referring to <FIG>, an electronic device <NUM> (e.g., the electronic device <NUM> of <FIG>) may include a side bezel structure <NUM>, a first support member <NUM> (e.g., a bracket), a front plate <NUM>, a display <NUM>, a printed circuit board <NUM>, a battery (or a battery pack) <NUM> (e.g., the battery <NUM> of <FIG>), a second support member <NUM> (e.g., a rear case), an antenna <NUM> (e.g., the antenna module <NUM> of <FIG>), and a rear plate <NUM>. Alternatively, at least one of the components (e.g., the first support member <NUM> or the second support member <NUM>) may be omitted from the electronic device <NUM>, or the electronic device <NUM> may additionally include other components.

The electronic device <NUM> may include a housing including a front face, a rear face, and a side face surrounding a space between the front face and the rear face. The term, housing may refer to a structure forming some of the front face, the rear face, and the side face. At least a portion of the front face may be formed by a substantially transparent front plate <NUM> (e.g., a glass plate or a polymer plate including various coating layers). The rear face may be formed of a substantially opaque rear plate <NUM>. The rear plate <NUM> may be formed of coated or colored glass, ceramic, a polymer, or a metal (e.g., aluminum, stainless steel (STS), or magnesium), or a combination of two or more of these materials. The side faces may be formed by a side bezel structure (or a "side member") <NUM> coupled to the front plate <NUM> and the rear plate <NUM> and including a metal and/or a polymer. Alternatively, the rear plate <NUM> and the side bezel structure <NUM> may be integrally formed, and may include the same material (e.g., a metal material such as aluminum).

The first support member <NUM> may be disposed inside the electronic device <NUM> and connected to the side bezel structure <NUM> or may be formed integrally with the side bezel structure <NUM>. The first support member <NUM> may be formed of a metal material and/or a non-metal (e.g., polymer) material. The display <NUM> may be coupled to one face of the first support member <NUM>, and the PCB <NUM> may be coupled to the other face of the first support member <NUM>. On the PCB <NUM>, a processor, a memory, and/or an interface may be mounted. The processor (e.g., the processor <NUM> of <FIG>) may include at least one of a CPU, an AP, a GPU, an ISP, a sensor hub processor, or a CP.

The memory may include a volatile memory or a nonvolatile memory.

The interface may include an HDMI, a USB interface, an SD card interface, and/or an audio interface. The interface may electrically or physically connect the electronic device <NUM> to an external electronic device, and may include a USB connector, an SD card/an MMC connector, or an audio connector.

The battery <NUM> supplies power to at least one component of the electronic device <NUM>, and may include a non-rechargeable primary battery, a rechargeable secondary battery, and/or a fuel cell. At least a part of the battery <NUM> may be disposed to be substantially flush with the PCB <NUM>. The battery <NUM> may be integrally disposed within the electronic device <NUM>, or may be mounted to be detachable from the electronic device <NUM>. The battery <NUM> may be a pouch type battery, in which a battery cell is embedded in a pouch type case of an aluminum laminated sheet. The battery <NUM> may be a jelly-roll type (a rolling type) or a stack type. Alternatively, the battery <NUM> may be a combination type of the jelly-roll type and the stack type.

The antenna <NUM> may include a near-field Communication (NFC) antenna, a wireless charging antenna, and/or a magnetic secure transmission (MST) antenna. The antenna <NUM> may perform short-range communication with an external device, or may transmit/receive power required for charging in a wireless manner to/from the external device. Alternatively, an antenna structure may be formed by the side bezel structure <NUM>, a part of the first support member <NUM>, or a combination thereof.

<FIG> illustrates an external appearance of a battery according to an embodiment. <FIG> illustrates an internal structure of a battery according to an embodiment. <FIG> illustrates a battery cell before rolling according to an embodiment. <FIG> illustrates a cross-sectional view of a battery cell in a rolling state according to an embodiment.

Referring to <FIG>, a battery <NUM> may include a pouch <NUM>, a battery cell <NUM>, a cathode tab <NUM>, and an anode tab <NUM>.

The pouch <NUM> (or a can) is a structure that provides an inner space <NUM>, in which the battery cell <NUM> is accommodated. A first plate <NUM> and a second plate <NUM> are disposed to be spaced apart from each other to define the inner space <NUM>. The pouch <NUM> may be formed of a metal such as aluminum or an aluminum alloy.

The battery cell <NUM> is provided by overlapping a cathode (or a cathode plate) <NUM>, an anode (an anode plate) <NUM>, and a separator <NUM> and winding them together. The battery cell <NUM> may have a jelly-roll form. Through a series of processes of disposing the battery cell <NUM> in the inner space <NUM> of the pouch <NUM>, injecting an electrolyte into the inner space <NUM>, and sealing the pouch <NUM>, the battery cell <NUM> may be disposed in the inner space <NUM> of the pouch <NUM> together with the electrolyte.

The cathode <NUM> may include a cathode base and a first joining material coated on the cathode base. The cathode base may include a plate or a layer (e.g., aluminum foil) including a metal such as aluminum. The first joining material may include a cathode material, a conductive agent, and a binder. The cathode material may be a material (e.g., nickel cobalt aluminum (NCM), nickel cobalt aluminum (NCA), or a lithium cobalt oxide (LCO)) that is engaged in an electrode reaction, the conductive agent may be a material for increasing conductivity, and the binder may increase a coupling force of the cathode material and the conductive agent. The cathode material may include a lithium-based oxide.

Referring to <FIG>, the cathode <NUM> may include a first coating area 321a coated with the first joining material and a first non-coating area 321b (e.g., a plain part) that is not coated with the first joining material. The first coating area 321a may be formed on opposite surfaces of the cathode <NUM>, or may be formed on one surface of the cathode <NUM>. The cathode tab <NUM> may be attached to the first non-coating area 321b. For example, a first cathode tab 331a is attached to a left end of the first non-coating area 321b, and a second cathode tab 331b may be attached to a right end of the first non-coating area 321b. The first cathode tab 331a and the second cathode tab 331b may be attached to portions (e.g., the first non-coating area 321b) of the cathode <NUM> by using an insulation tape.

The anode <NUM> may include an anode base and a second joining material coated on a surface of the anode base. The anode base may include a plate or a layer (e.g., copper foil) including a metal such as copper. The second joining material may include an anode material, a conductive agent, and a binder. The anode material may include carbon.

The cathode <NUM> may include a second coating area 322a coated with the second joining material and a second non-coating area 322b (e.g., a plain part) that is not coated with the second joining material. The second coating area 322a may be formed on opposite surfaces of the anode <NUM>, or may be formed on one surface of the anode <NUM>. The anode tab <NUM> may be attached to the second non-coating area 322b. For example, a first anode tab 332a may be attached to a left end of the second non-coating area 322b, and a second anode tab 332b may be attached to a right end of the first non-coating area 322b. The first anode tab 332a and the second anode tab 332b may be attached to portions (e.g., the second non-coating area 322b) of the anode <NUM> by using an insulation tape.

The electrolyte is injected into the pouch <NUM>, and may be disposed in the interior of the pouch <NUM> together with the cathode tab <NUM> and the anode tab <NUM>. The electrolyte is a medium that chemically balances an oxidation reaction or a reduction reaction that occurs in the cathode <NUM> or the anode <NUM>, and may include a material in a liquid, solid, or gel state. For example, during charging of the battery <NUM>, through oxidation of the cathode <NUM> and reduction of the anode <NUM>, lithium ions generated in the cathode <NUM> move to the anode <NUM> via the electrolyte, and electrons may move from the cathode <NUM> to the anode <NUM> along a circuit (e.g., the power management module <NUM> of <FIG>) connected to the cathode tab <NUM> and the anode tab <NUM>. During discharging of the battery <NUM>, through reduction of the cathode <NUM> and oxidation of the anode <NUM>, lithium ions generated in the anode <NUM> move to the cathode <NUM> via the electrolyte, and electrons may move from the anode <NUM> to the cathode <NUM> along a circuit (e.g., the power management module <NUM> of <FIG>) connected to the cathode tab <NUM> and the anode tab <NUM>. During the discharging of the battery <NUM>, the chemical energy of the cathode material of the cathode <NUM>, the anode material of the anode <NUM>, and the electrolyte may be converted to electric energy, and electric power may be supplied to the corresponding circuit through the cathode tab <NUM> connected to the cathode <NUM> and the anode tab <NUM> connected to the anode <NUM>.

The separator <NUM> may be disposed between the cathode <NUM> and the anode <NUM> to prevent a physical contact between the cathode <NUM> and the anode <NUM>. The separator <NUM> may prevent a short-circuit between the cathode <NUM> and the anode <NUM> and may allow ions to move. The separator <NUM> may allow the ion to move through fine holes to allow electric charges to flow, and may be formed of various materials to have porosity. The separator <NUM> may include at least one of polyethylene (PE) or polypropylene (PP). The separator <NUM> may be formed of a single layer including PE or PP, or may be formed of a dual layer in which a layer of PE and a layer of PP are joined to each other. As another example, the separator <NUM> may be formed of a triple layer in which a layer of PP, a layer of PE, and another layer of PP are joined to each other.

The cathode tab <NUM> may be electrically connected to the cathode <NUM>, and may protrude (be exposed) to the outside of the cathode <NUM>. The cathode tab <NUM> may include a plurality of tabs (e.g., the first cathode tab 331a and the second cathode tab 331b), and may be joined (e.g., through binding or welding) to the cathode terminal. The cathode tab <NUM> may include an area (i.e., a first area) that is not exposed to the outside when the cathode tab <NUM> contacts the cathode <NUM> and is rolled, and another area (i.e., a second area) that is exposed to the outside. The first cathode tab 331a and the second cathode tab 331b may be disposed in the cathode <NUM> such that the first areas do not overlap each other when viewed from the top of one surface (e.g., a front surface or a rear surface) of the battery cell <NUM>. The second area of the cathode tab <NUM> may have an unstructured shape. That is, the shape of second area of the cathode tab <NUM> does not have a specific pattern or a regular pattern such as a structure shape (e.g., a rectangular shape or a tetragonal shape), but has a pattern having irregular shapes or irregular patterns.

The anode tab <NUM> may be electrically connected to the anode <NUM>, and may protrude to the outside of the anode <NUM>. The anode tab <NUM> may include a plurality of tabs (e.g., the first anode tab 332a and the second anode tab 332b), and may be joined (e.g., through binding or welding) to the anode terminal. The anode tab <NUM> may include an area (i.e., a third area) that contacts the anode <NUM> and is not exposed to the outside, and another area (i.e., a fourth area) that is exposed to the outside. The first anode tab 332a and the second anode tab 332b may be disposed in the anode <NUM> such that the third areas do not overlap each other when viewed from the top of one surface (e.g., a front surface or a rear surface) of the battery cell <NUM>. The fourth area of the anode tab <NUM> may have an unstructured shape.

Referring to <FIG>, the battery cell <NUM> may be rolled, such that the cathode tab <NUM> and the anode tab <NUM> may be disposed not to overlap each other when viewed from the vertically upper side in a state in which the battery cell <NUM> is rolled. Further, at least portions of the first cathode tab 331a and the second cathode tab 331b also may be disposed not to overlap each other. For example, first areas of the first cathode tab 331a and the second cathode tab 331b also may be disposed not to overlap each other. Similarly, at least portions of the first anode tab 332a and the second anode tab 332b also may be disposed not to overlap each other. For example, first areas of the first anode tab 332a and the second anode tab 332b may be disposed not to overlap each other. For convenience of description, <FIG> does not illustrate a separator <NUM> between the cathode <NUM> and the anode <NUM>.

The battery <NUM> may minimize an increase in the thickness of the battery cell <NUM> by disposing the first areas of the first cathode tab 331a and the second cathode tab 331b and the third areas of the first anode tab 332a and the second anode tab 332b such that at least they do not overlap each other. For example, assuming that the thicknesses of the cathode <NUM> and the anode <NUM> are <NUM> and the thicknesses of the first cathode tab 331a, the second cathode tab 331b, the first anode tab 332a, and the second anode tab 332b are <NUM>, the vertical thickness of the battery cell <NUM> may be approximately <NUM> (= <NUM> * <NUM> (five cathodes and five anode are alternately stacked) + <NUM>). For convenience of description, the thickness of the separator <NUM> is not considered.

Unlike <FIG>, when the first cathode tab 331a, the second cathode tab 331b, the first anode tab 332a, and the second anode tab 332b are disposed such that at least portions thereof the overlap each other, the thickness of the battery cell <NUM> may increase by the number of the overlapping tabs. For example, when two tabs overlap each other, the thickness of the battery cell <NUM> increases by <NUM> as compared with the embodiment of <FIG>, which has been described above whereby the vertical thickness of the battery cell <NUM> may become approximately <NUM> (= <NUM> + <NUM>). When four tabs overlap each other, the thickness of the battery cell <NUM> increases by <NUM> as compared with the embodiment of <FIG>, which has been described above whereby the vertical thickness of the battery cell <NUM> may become approximately <NUM> (= <NUM> + <NUM>).

The above-structured battery <NUM> may convert chemical energy of the cathode <NUM> and the anode <NUM> to electric energy, and may supply the converted energy (electric power) to some configurations (e.g., the power management module <NUM>) of the electronic device or receive energy from another configuration (e.g., a charging circuit) through the cathode tab <NUM> connected to the cathode <NUM> and the anode tab <NUM> connected to the anode <NUM>. The cathode tab <NUM> and the anode tab <NUM> may be connected to some configurations of the electronic device through an electric circuit (e.g., a battery protecting circuit).

<FIG> illustrates a structure and a welding location of an electrode tab according to an embodiment.

Referring to <FIG>, as illustrated in view <NUM>, an electrode tab <NUM> (e.g., the cathode tab <NUM> or the anode tab <NUM>) may include a first electrode tab 611a and a second electrode tab 611b, which have unstructured shapes. The first electrode tab 611a (e.g., the first cathode tab 331a or the first anode tab 332a) may include a first area 611a-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) that is not to be exposed to the outside and a second area 611a-<NUM> exposed to the outside. Similarly, the second electrode tab 611b (e.g., the second cathode tab 331b or the second anode tab 332b) may include a third area 611b-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) that is not to be exposed to the outside and a fourth area 611b-<NUM> exposed to the outside.

As illustrated in view <NUM>, the first electrode tab 611a and the second electrode tab 611b may be coupled to each other to be formed as a single body. For example, a plurality of corners of the first electrode tab 611a and the second electrode tab 611b may be coupled to be engaged with each other like puzzle pieces.

View <NUM> illustrates an example in which five corners <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> of the first electrode tab 611a and the second electrode tab 611b are coupled to engaged with each other. However, the disclosure is not limited thereto, and two to four corners of the first electrode tabs 611a and the second electrode tabs 611b may be engaged with each other, or six or more corners thereof may be engaged with each other.

In view <NUM>, the first electrode tab 611a and the second electrode tab 611b formed as a single body may be coupled to the electrode terminal <NUM>. The first electrode tab 611a and the second electrode tab 611b may be coupled to the electrode terminal <NUM> through ultrasonic welding or binding.

At least some of the corners of the first electrode tab 611a and the second electrode tab 611b having unstructured shapes, which are coupled to be engaged with each other, may have directions that are different from those of other corners. This helps disperse an external impact applied to a coupling portion of the first electrode tab 611a and the second electrode tab 611b to a plurality of directions. For example, the first electrode tab 611a and the second electrode tab 611b may include corners coupled (e.g., welded) in a first direction <NUM> (e.g., a longitudinal direction) and corners coupled in a second direction <NUM> (e.g., a transverse direction) in order to prevent the first electrode tab 611a and the second electrode tab 611b from being separated from each other due to an external impact (an impact that damages the coupling in the first direction) related to the first direction through coupling in the second direction when the external impact related to the first direction is generated. This may also prevent the first electrode tab 611a and the second electrode tab 611b from being separated from each other by an external impact (an impact that damages the coupling in the second direction) related to the second direction through coupling in the first direction when the external impact related to the second direction is generated.

Unlike <FIG>, when the first electrode tab and the second electrode tab have structured shapes (e.g., a rectangular shape), the first electrode tab and the second electrode tab may be disposed in parallel in the second direction <NUM> and only the corners in the first direction <NUM> may be coupled to each other. The first electrode tab and the second electrode tab having structured shapes of the coupling structure may be vulnerable to an external impact related to the first direction. In contrast, the first electrode tab 611a and the second electrode tab 611b of <FIG> may be robust to both external impacts related to the first direction and/or the second direction.

Further, the first electrode tab 611a and the second electrode tab 611b having the unstructured shapes may be robust to an external impact because they have more coupled portions than the first electrode tab and the second electrode tab having structured shapes (i.e., the total length of the coupled portion is larger).

Referring to <FIG>, an electrode tab <NUM> (e.g., the cathode tab <NUM> or the anode tab <NUM>) may include a first electrode tab 711a and a second electrode tab 711b, which have unstructured shapes. The first electrode tab 711a (e.g., the first cathode tab 331a or the first anode tab 332a) may include a first area 711a-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) not to be exposed to the outside and a second area 711a-<NUM> exposed to the outside. Similarly, the second electrode tab 711b (e.g., the second cathode tab 331b or the second anode tab 332b) may include a third area 711b-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) not to be exposed to the outside and a fourth area 711b-<NUM> exposed to the outside.

Because the extents of the second area 711a-<NUM> and the fourth area 711b-<NUM> of the electrode tab <NUM> are larger than the extents of the first area 711a-<NUM> and the third area 711b-<NUM>, the area <NUM> coupled (e.g., welded) to the electrode terminal may be secured and coupling strength may be improved. The improvement of the coupling strength due to the securement of the coupling area <NUM> can prevent the first electrode tab 711a and the second tab 711b from being separated from each other by an external impact.

<FIG> illustrates a structure and a welding location of an electrode tab according to an embodiment of the disclosure.

Referring to <FIG>, as illustrated in view <NUM>, an electrode tab <NUM> (e.g., the cathode tab <NUM> or the anode tab <NUM>) may include a first electrode tab 811a and a second electrode tab 811b, which have unstructured shapes. The first electrode tab 811a (e.g., the first cathode tab 331a or the first anode tab 332a) may include a first area 811a-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) not to be exposed to the outside and a second area 811a-<NUM> exposed to the outside. Similarly, the second electrode tab 811b (e.g., the second cathode tab 331b or the second anode tab 332b) may include a third area 811b-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) not to be exposed to the outside and a fourth area 811b-<NUM> exposed to the outside.

As illustrated in view <NUM>, the first electrode tab 811a and the second electrode tab 811b may be coupled to each other to form a single body. For example, the first electrode tab 811a and the second electrode tab 811b may be coupled to each other such that some areas 811c overlap each other to be formed as a single body.

As illustrated in view <NUM>, the coupled first electrode tab 811a and second electrode tab 811b may be joined to the electrode terminal <NUM>. The first electrode tab 811a and the second electrode tab 811b may be coupled to the electrode terminal <NUM> through ultrasonic welding or binding. The overlapping areas 811c of the first electrode tab 811a and the second electrode tab 811b may be joined to each other. Accordingly, the coupling strength of the first electrode tab 811a and the second electrode tab 811b may be improved.

Referring to <FIG>, as illustrated in view <NUM>, an electrode tab <NUM> (e.g., the cathode tab <NUM> or the anode tab <NUM>) may include a first electrode tab 911a of a unstructured shape and a second electrode tab 911b of a structured shape. The first electrode tab 911a (e.g., the first cathode tab 331a or the first anode tab 332a) may include a first area 911a-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) not to be exposed to the outside and a second area 911a-<NUM> exposed to the outside. Similarly, the second electrode tab 911b (e.g., the second cathode tab 331b or the second anode tab 332b) may include a third area 911b-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) not to be exposed to the outside and a fourth area 911b-<NUM> exposed to the outside.

The electrode tab <NUM> of <FIG> is similar to the electrode tab <NUM> of <FIG>, except that the shapes are different. For example, as illustrated in view <NUM>, the first electrode tab 911a and the second electrode tab 911b may be coupled to each other such that some areas 911c thereof overlap each other.

As illustrated in view <NUM>, the first electrode tab 911a and the second electrode tab 911b may be joined to the electrode terminal <NUM>. Because the electrode tab <NUM> of <FIG> is coupled to the electrode terminal <NUM> and the areas 911c of the first electrode 911a and the second electrode tab 911b are joined to overlap each other, the coupling strength of the first electrode tab 911a and the second electrode tab 911b may be improved.

Referring to <FIG>, as illustrated in view <NUM>, an electrode tab <NUM> (e.g., the cathode tab <NUM> or the anode tab <NUM>) may include a first electrode tab 1011a and a second electrode tab 1011b, which have unstructured shapes. The first electrode tab 1011a (e.g., the first cathode tab 331a or the first anode tab 332a) may include a first area 1011a-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) not to be exposed to the outside and a second area 1011a-<NUM> exposed to the outside. Similarly, the second electrode tab 1011b (e.g., the second cathode tab 331b or the second anode tab 332b) may include a third area 1011b-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) not to be exposed to the outside and a fourth area 1011b-<NUM> exposed to the outside.

The electrode tab <NUM> of <FIG> is similar to the electrode tab <NUM> of <FIG>, except that the shapes thereof are different. For example, as illustrated in view <NUM>, the first electrode tab 1011a and the second electrode tab 1011b may be coupled to each other such that some areas 1011c thereof overlap each other.

As illustrated in view <NUM>, the first electrode tab 1011a and the second electrode tab 1011b may be joined to the electrode terminal <NUM>. Because the electrode tab <NUM> of <FIG> is coupled to the electrode terminal <NUM> and the areas 1011c of the first electrode 1011a and the second electrode tab 1011b are matched to overlap each other, the coupling strength of the first electrode tab 1011a and the second electrode tab 1011b may be improved.

Referring to <FIG>, as illustrated in view <NUM>, an electrode tab <NUM> (e.g., the cathode tab <NUM> or the anode tab <NUM>) may include a first electrode tab 1111a and a second electrode tab 1111b, which have unstructured shapes. The first electrode tab 1111a (e.g., the first cathode tab 331a or the first anode tab 332a) may include a first area 1111a-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) not to be exposed to the outside and a second area 1111a-<NUM> exposed to the outside. Similarly, the second electrode tab 1111b (e.g., the second cathode tab 331b or the second anode tab 332b) may include a third area 1111b-<NUM> attached to an electrode (e.g., the cathode <NUM> or the anode <NUM>) not to be exposed to the outside and a fourth area 1111b-<NUM> exposed to the outside.

The electrode tab <NUM> of <FIG> is similar to the electrode tab <NUM> of <FIG>, except that the shapes thereof are different. For example, as illustrated in view <NUM>, the first electrode tab 1111a and the second electrode tab 1111b may be coupled to each other such that some areas 1111c thereof overlap each other.

As illustrated in view <NUM>, the first electrode tab 1111a and the second electrode tab 1111b may be joined to the electrode terminal <NUM>. Because the electrode tab 1111a of <FIG> is coupled to the electrode terminal <NUM> and the areas 1111c of the first electrode 1111a and the second electrode tab 1111b are matched to overlap each other, the coupling strength of the first electrode tab 1111a and the second electrode tab 1111b may be improved.

As described above, the coupling strengths (e.g., the welding strengths) of the electrode tabs <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> of the unstructured structures described in <FIG> can be improved by increasing the joining extents of the first electrode tabs 611a, 711a, 811a, 911a, 1011a, and 1111a and the second electrode tabs 611b, 711b, 811b, 911b, 1011b, and 1111b, by configuring the first electrode tabs 611a, 711a, 811a, 911a, 1011a, and 1111a and the second electrode tabs 611b, 711b, 811b, 911b, 1011b, and 1111b such that at least portions of the areas exposed to the outside overlap each other, or by coupling the corners of a plurality of directions such that the corners are engaged with each other.

<FIG> illustrates a coupling structure of a plurality of electrode tabs according to an embodiment.

Referring to <FIG>, a battery cell <NUM> (e.g., the battery cell <NUM>) may include a first electrode tab <NUM> (e.g., the first cathode tab 331a or the first anode tab 332a), a second electrode tab <NUM> (e.g., the second cathode tab 331b or the second anode tab 332b), an electrode terminal <NUM>, a first electrode <NUM> (e.g., the cathode <NUM>), a second electrode <NUM> (e.g., the anode <NUM>), and a separator <NUM> (e.g., the separator <NUM>).

The first electrode tab <NUM> and the second electrode tab <NUM> may be disposed in the first electrode <NUM> or the second electrode <NUM>. Hereinafter, a description will be made with the assumption that the first electrode tab <NUM> and the second electrode tab <NUM> are disposed in the second electrode <NUM>. For example, the first electrode tab <NUM> may be disposed to protrude at a first location of the second electrode <NUM>, and the second electrode tab <NUM> may be disposed to protrude at a second location of the second electrode <NUM>.

The first electrode tab <NUM> may include bending parts 1201a and 1201b. For example, the first electrode tab <NUM> may include a first bending part 1201a that is bent at the first location of the second electrode <NUM> and a second bending part 1201b that is bent around the second electrode tab <NUM>. The first bending part 1201a and the second bending part 1201b of the first electrode tab <NUM> are bent by approximately <NUM> degrees, but the disclosure is not limited thereto and may be bent at various angles.

After the exposed part (the second area) of the first electrode tab <NUM> is bent, it may be disposed in parallel to the exposed part (the fourth area) of the second electrode tab <NUM> while not overlapping the exposed part of the second electrode tab <NUM>. At least portions of the second area of the first electrode tab <NUM> and the fourth area of the second electrode tab <NUM> may overlap each other, e.g., as illustrated in <FIG>.

The first electrode tab <NUM> and the second electrode tab <NUM> formed as a single body through bending may then be joined (through binding or welding) to the electrode terminal <NUM>.

The battery cell <NUM> is similar to the battery cell <NUM> of <FIG>, except that the battery cell <NUM> may have a different shape of the first electrode tab <NUM>. For example, the first electrode tab <NUM> may be disposed to protrude at the first location of the second electrode <NUM> to be inclined toward the second electrode tab <NUM>. The first electrode tab <NUM> may be bent at a specific angle (less than about <NUM> degrees to <NUM> degrees) toward the second electrode tab <NUM> at the first bending part 1221a, may be bent to be parallel to the second electrode tab <NUM> at the second bending part 1221b, and may be integrally formed with the second electrode tab <NUM>. Because the other configurations of the battery cell <NUM> are the same as <FIG>, a detailed description of the other configurations of the battery cell <NUM> will be omitted to avoid a repeated description thereof.

<FIG> illustrates a coupling structure of a plurality of electrode tabs according to an embodiment of the disclosure.

The battery cell <NUM> is similar to the battery cell <NUM> of <FIG>, except that the battery cell <NUM> may be configured such that the electrode terminal <NUM> is located between the first electrode tab <NUM> and the second electrode tab <NUM>. For example, the first electrode tab <NUM> may be joined to a first surface 1243a of the electrode terminal <NUM>, and the second electrode tab <NUM> may be joined to a second surface 1243b of the electrode terminal <NUM> located on an opposite side to the first surface 1243a. Because the other configurations of the battery cell <NUM> are the same as <FIG>, a detailed description of the other configurations of the battery cell <NUM> will be omitted to avoid a repeated description thereof.

<FIG> illustrates a battery cell before rolling according to an embodiment. <FIG> illustrates a battery cell in a rolling state according to an embodiment.

Referring to <FIG> and <FIG>, a battery cell <NUM> may be configured such that three or more electrode tabs are coupled to each other to form one electrode tab <NUM> (e.g., the cathode tab <NUM> or the anode tab <NUM>).

As illustrated in <FIG>, the electrode tab <NUM> may be formed by coupling four electrode tabs 1351a, 1351b, 1351c, and 1351d.

The four electrode tabs 1351a, 1351b, 1351c, and 1351d may include an area (a first area) that contacts the electrode <NUM> and is not exposed to the outside and an area (a second area) that is exposed (or protrudes) to the outside.

The first areas of the fourth electrode tabs 1351a, 1351b, 1351c, and 1351d may be disposed in the electrode <NUM> not to overlap each other when viewed from the top of one surface (e.g., a front surface or a rear surface) of the battery cell <NUM> in a state in which the electrode <NUM> is rolled. The second areas of the four electrode tabs 1351a, 1351b, 1351c, and 1351d have unstructured shapes, and are coupled to each other to form one electrode tab. The one electrode tab, in which the four electrode tabs 1351a, 1351b, 1351c, and 1351d having the unstructured shapes are coupled to each other, may be structured. The second areas, as illustrated in <FIG>, may not overlap each other.

At least some of the second areas, as illustrated in <FIG>, may overlap each other. For example, some areas of the first electrode tab 1351a and the second electrode tab 1351b may overlap each other, the second electrode tab 1351b and the third electrode tab 1351c may not overlap each other, and the third electrode tab 1351c and the fourth electrode tab 1351d may not overlap each other. Further, some areas of the first electrode tab 1351a and the second electrode tab 1351b may overlap each other, some areas of the second electrode tab 1351b and the third electrode tab 1351c may overlap each other, and some areas of the third electrode tab 1351c and the fourth electrode tab 1351d may overlap each other. Further, some areas of the first electrode tab 1351a and the second electrode tab 1351b may overlap each other, and some areas of the third electrode tab 1351c and the fourth electrode tab 1351d may overlap each other.

<FIG> illustrates a battery cell before stacking according to an embodiment.

Referring to <FIG>, a battery cell <NUM> may be of a stack type. In describing the stack type battery cell below, a configuration that is substantially the same as the configuration of the above-described jelly-roll type battery cell will be omitted, and only the differences will be described.

The battery cell <NUM> may include first to fourth electrodes 1452a, 1452b, 1452c, and 1452d and first to fourth electrode tabs 1451a, 1451b, 1451c, and 1451d.

The first to fourth electrode tabs 1451a, 1451b, 1451c, and 1451d may be attached to (disposed in) the first to fourth electrodes 1452a, 1452b, 1452c, and 1452d. The first to fourth electrodes 1452a, 1452b, 1452c, and 1452d may be stacked to form one battery cell <NUM>. When the first to fourth electrodes 1452a, 1452b, 1452c, and 1452d are stacked, the first to fourth electrode tabs 1451a, 1451b, 1451c, and 1451d may be disposed to not overlap each other.

The first to fourth electrode tabs 1451a, 1451b, 1451c, and 1451d may include an area (i.e., a first area) that contacts the first to fourth electrodes 1452a, 1452b, 1452c, and 1452d and is not exposed to the outside and an area (i.e., a second area) that is exposed (protrudes) to the outside.

The first areas of the first to fourth electrode tabs 1451a, 1451b, 1451c, and 1451d may be disposed to not overlap each other when viewed from the top of one surface (e.g., a front surface or a rear surface) of the battery cell <NUM>. The second areas of the first to fourth electrode tabs 1451a, 1451b, 1451c, and 1451d have unstructured shapes, and are coupled to each other to form one electrode tab. The one electrode tab, in which the first to fourth electrode tabs 1451a, 1451b, 1451c, and 1451d having the unstructured shapes are coupled to each other may be structured. The second areas may not overlap each other. At least some areas of at least some of the second areas may overlap each other.

Although <FIG> illustrates the battery cell <NUM> including the four electrodes 1452a, 1452b, 1452c, and 1452d and the four electrode tabs 1451a, 1451b, 1451c, and 1451d, the disclosure is not limited thereto. For example, the battery cell <NUM> may include two, three, five, or more electrodes and electrode tabs.

Further, although <FIG> illustrates that the electrode tabs are attached to the four electrodes 1452a, 1452b, 1452c, and 1452d, respectively, the disclosure is not limited thereto. For example, the battery cell <NUM> may be configured such that the electrode tabs are attached to two or more electrodes among the four electrodes 1452a, 1452b, 1452c, and 1452d. For example, the first electrode tab 1451a may be attached to the first electrode 1452a, the second electrode tab 1452b may not be attached to the second electrode 1452b, the third electrode 1452c may be attached to the third electrode tab 1451c, and the fourth electrode 1452d may not be attached to the fourth electrode tab 1451d.

According to an embodiment of the disclosure, a battery (e.g., the battery <NUM>, <NUM>) may include a pouch (e.g., the pouch <NUM>); a battery cell (e.g., the battery cell <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising a cathode (e.g., the cathode <NUM>, the first electrode <NUM>, <NUM>, <NUM>), an anode (e.g., the anode <NUM>, the second electrode <NUM>, <NUM>, <NUM>), and a separator (e.g., the separator <NUM>) located between the cathode and the anode, and accommodated in the pouch; a plurality of cathode tabs (e.g., the first cathode tab 331a. the second cathode tab 331b, the first electrode tab 611a, 711a, 811a, 911a, <NUM> a, 1111a, <NUM>, <NUM>, <NUM>), each of which comprises a first area electrically connected to the cathode and an unstructured second area extending to protrude from the first area to the outside of the cathode; a plurality of anode tabs (e.g., the first anode tab 32a, the second tab 32b, the second electrode tab 611b, 711b, 811b, 911b, 1011b, 1111b, <NUM>, <NUM>, <NUM>) each of which comprises a third area electrically connected to the anode and an unstructured fourth area extending to protrude from the third area to the outside of the anode; a cathode terminal joined(or attached) to the second areas of the plurality of cathode tabs; and an anode terminal joined(or attached) to the fourth areas of the plurality of anode tabs. The cathode tabs are disposed in the cathode such that the first areas do not overlap each other when viewed from the top of one surface of the battery cell, and the second areas are coupled to each other as a single body. The anode tabs are disposed in the anode such that the third areas do not overlap each other when viewed from the top of one surface of the battery cell, and the fourth areas are coupled to each other as a single body.

The second areas of the plurality of cathode tabs may be coupled to each other such that at least portions thereof overlap each other, and the fourth areas of the plurality of anode tabs may be coupled to each other such that at least portions thereof overlap each other. The widths of the second areas of the plurality of cathode tabs and the fourth areas of the plurality of anode tabs may be larger than the widths of the first areas of the plurality of cathode tabs and the third areas of the plurality of anode tabs, respectively.

The second areas of the plurality of cathode tabs may be coupled to each other such that a plurality of corners (e.g., the corners <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) thereof are engaged with each other, and the fourth areas of the plurality of cathode tabs may be coupled to each other such that a plurality of corners (e.g., the corners <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) thereof are engaged with each other.

At least some of the plurality of corners of the cathode tabs may have different directions, and at least some of the corners of the anode tabs have different directions.

One side surface of the cathode terminal may be j oined to the second areas of the plurality of the cathode tabs, and one side surface of the anode terminal may be joined to the fourth areas of the plurality of the anode tabs.

The cathode terminal may be located between the plurality of cathode tabs such that opposite side surfaces thereof may be joined to the second areas of the plurality of cathode tabs, and the anode terminal may be located between the plurality of anode tabs such that opposite side surfaces thereof may be joined to the fourth areas of the plurality of anode tabs.

At least some of the plurality of cathode tabs may comprise one or more bending parts (e.g., the first bending part 1201a, 1221a, the second bending part 1201b, 1221b), and at least some of the plurality of anode tabs may comprise one or more bending parts (e.g., the first bending part 1201a, 1221a, the second bending part 1201b, 1221b).

The battery cell may include at least one of a jelly-roll type battery cell or a stack type battery cell.

The cathode terminal and the anode terminal may be respectively joined to the plurality cathode tabs and the plurality of anode tabs through binding or ultrasonic welding.

According to an embodiment, an electronic device (e.g., the electronic device <NUM>, <NUM>) may comprise a housing; a display (e.g., the display device <NUM>, the display <NUM>) viewed through at least a portion of the housing; and a battery (e.g., the battery <NUM>, <NUM>) disposed within the housing. The battery comprises a pouch (e.g., the pouch <NUM>); a battery cell (e.g., the battery cell <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising a cathode (e.g., the cathode <NUM>, the first electrode <NUM>, <NUM>, <NUM>), an anode (e.g., the anode <NUM>, the second electrode <NUM>, <NUM>, <NUM>), and a separator (e.g., the separator <NUM>) located between the cathode and the anode, and accommodated in the pouch; a plurality of cathode tabs (e.g., the first cathode tab 331a, the second cathode tab 331b, the first electrode tab 611a, 711a, 811a, 911a, 1011a, 1111a, <NUM>, <NUM>, <NUM>), each of which comprises a first area electrically connected to the cathode and an unstructured second area extending to protrude from the first area to outside of the cathode; a plurality of anode tabs (e.g., the first anode tab 32a, the second tab 32b, the second electrode tab 611b, 711b, 811b, 911b, 1011b, 1111b, <NUM>, <NUM>, <NUM>), each of which comprises a third area electrically connected to the anode and an unstructured fourth area extending to protrude from the third area to outside of the anode; a cathode terminal joined(or attached) to the second areas of the plurality of cathode tabs; and an anode terminal joined(or attached) to the fourth areas of the plurality of anode tabs. The cathode tabs are disposed in the cathode such that the first areas do not overlap each other when viewed from the top of one surface of the battery cell, and the second areas are coupled to each other as a single body. The anode tabs are disposed in the anode such that the third areas do not overlap each other when viewed from the top of one surface of the battery cell, and the fourth areas are coupled to each other as a single body.

The second areas of the plurality of cathode tabs may be coupled to each other such that at least portions thereof overlap each other, and the fourth areas of the plurality of anode tabs may be coupled to each other such that at least portions thereof overlap each other.

The widths of the second areas of the plurality of cathode tabs and the fourth areas of the plurality of anode tabs may be larger than the widths of the first areas of the plurality of cathode tabs and the third areas of the plurality of anode tabs, respectively.

The second areas of the plurality of cathode tabs may be coupled to each other such that a plurality of corners (e.g., the corners <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) thereof may be engaged with each other, and the fourth areas of the plurality of cathode tabs may be coupled to each other such that a plurality of corners (e.g., the corners <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) thereof may be engaged with each other.

An electronic device according to an embodiment may include a portable communication device (e.g., a smartphone), a computer device, a portable multimedia device, a portable medical device, a camera, a wearable device, or a home appliance. However, the electronic device is not limited to those above- described examples.

A singular form of a noun corresponding to an item may include one or more of the things, unless the relevant context clearly indicates otherwise.

As used herein, such terms as "1st" and "2nd," or "first" and "second" may be used to simply distinguish a corresponding component from another, and do not limit the components in other aspect (e.g., importance or order).

If an element (e.g., a first element) is referred to, with or without the term "operatively" or "communicatively", as "coupled with," "coupled to," "connected with," or "connected to" another element (e.g., a second element), it means that the element may be coupled with the other element directly (e.g., wiredly), wirelessly, or via a third element.

For example, a module may be implemented in the form of an application-specific integrated circuit (ASIC).

Various embodiments as set forth herein may be implemented as software (e.g., the program <NUM>) including one or more instructions that are stored in a storage medium (e.g., internal memory <NUM>, or external memory <NUM>) that is readable by a machine (e.g., the electronic device <NUM>, <NUM>). For example, a processor (e.g., the processor <NUM>) of the machine (e.g., the electronic device <NUM>, <NUM>) may invoke at least one of the one or more instructions stored in the storage medium, and execute it, with or without using one or more other components under the control of the processor. The term "non-transitory" simply means that the storage medium is a tangible device, and does not include a signal (e.g., an electromagnetic wave), but this term does not differentiate between where data is semi-permanently stored in the storage medium and where the data is temporarily stored in the storage medium.

A method according to an embodiment of the disclosure may be included and provided in a computer program product.

Claim 1:
A battery (<NUM>), comprising:
a pouch (<NUM>);
a battery cell (<NUM>) comprising a cathode (<NUM>), an anode (<NUM>), and a separator (<NUM>) located between the cathode (<NUM>) and the anode (<NUM>), and accommodated in the pouch (<NUM>);
characterized in,
a plurality of cathode tabs (<NUM>; 331a, 331b), each of which comprises a first area electrically connected to the cathode (<NUM>) and an unstructured second area extending to protrude from the first area to outside of the cathode (<NUM>);
a plurality of anode tabs (<NUM>; 332a, 332b), each of which comprises a third area electrically connected to the anode (<NUM>) and an unstructured fourth area extending to protrude from the third area to outside of the anode (<NUM>);
a cathode terminal (<NUM>) joined to the second areas of the cathode tabs (<NUM>; 331a, 331b); and
an anode terminal (<NUM>) joined to the fourth areas of the anode tabs (<NUM>; 332a, 332b),
wherein the cathode tabs (<NUM>; 331a, 331b) are disposed in the cathode (<NUM>) such that the first areas do not overlap each other when viewed from the top of one surface of the battery cell (<NUM>), and the second areas are coupled to each other, and
wherein the anode tabs (<NUM>; 332a, 332b) are disposed in the anode (<NUM>) such that the third areas do not overlap each other when viewed from the top of one surface of the battery cell (<NUM>), and the fourth areas are coupled to each other.