Abstract: A manufacturing method for a secondary battery and a manufacturing apparatus for a secondary battery that are applicable to a secondary battery in which an electrolyte solution injection hole has a diameter of 1.5 mm or more are provided. The secondary battery includes a battery case including a cover plate provided with an electrolyte solution injection hole, and a sealing member sealing the electrolyte solution injection hole. The manufacturing method includes a preparing step and a press-fitting step. The preparing step is preparing a cell in which, after an electrolyte solution is injected to the battery case through the electrolyte solution injection hole, the sealing member is disposed on the electrolyte solution injection hole. The press-fitting step is press-fitting the sealing member into the electrolyte solution injection hole while applying press-fitting load and ultrasonic vibration with a frequency of 20 kHz or more in parallel to a press-fitting direction.

Abstract: The invention provides a battery module for improving safety, which comprises at least one fixing frame, a plurality of battery cells, a plurality of conductive sheets and a plurality of protection units. The battery cells are arranged on the fixing frame. Each conductive sheet is connected with two battery cells in series, each of the protection units is respectively connected with two conductive sheets, and the battery cells connected with the conductive sheets are connected in parallel via the protection unit. When the temperature of the protection unit is greater than a preset temperature, the protection unit will be blown, thereby preventing the battery cells from charging the defective battery cell, resulting in the defective battery cell to melt or explode.

Abstract: The present disclosure provides a battery pack. The battery pack includes: a bare cell; a circuit module arranged in parallel to a terrace portion of the bare cell and connected to a tab of the bare cell; and a holder surrounding two surfaces of the circuit module and the terrace portion of the bare cell.

Abstract: Provided is a wearable display apparatus including a display element, an electronic circuit board, a circuit board holder configured to hold an electronic circuit board, and an exterior case configured to accommodate the display element and the circuit board, wherein an inner seal structure is provided in a location where the circuit board holder faces an opposing connecting portion of the exterior case from an inner side thereof.

Abstract: According to the present invention, a dummy terminal is provided on a sensing substrate and sensing substrate may be thus commonly used on both side surfaces of a battery module, and as a result, since only one type of sensing substrate provided with the dummy terminal needs to be manufactured instead of manufacturing two types of sensing substrates having different arrangements of the substrate terminals, mass productivity of the sensing substrate and the battery module including the same may be significantly improved.

Abstract: A battery capable of changing its form safely is provided. A bendable battery having a larger thickness is provided. A battery with increased capacity is provided. For an exterior body of the battery, a film in the shape of a periodic wave in one direction is used. A space is provided in an area surrounded by the exterior body and between an end portion of the electrode stack that is not fixed and an interior wall of the exterior body. Furthermore, the phases of waves of a pair of portions of the exterior body between which the electrode stack is located are different from each other. In particular, the phases are different from each other by 180 degrees so that wave crest lines overlap with each other and wave trough lines overlap with each other.

Abstract: A battery pack includes a fire extinguishing system. The battery pack includes: a housing; a battery module in the housing and including a plurality of spaced apart battery cells; an agent storage unit storing a fire extinguishing agent and injecting the fire extinguishing agent into the housing when an abnormal temperature is detected; a first perforated plate at a side of an inflow passage of the housing where the fire extinguishing agent flows from the agent storage unit to the housing, including a plurality of first opening holes for passing the fire extinguishing agent and guiding the fire extinguishing agent to a connection passage between the respective battery cells, and uniformly distributing the fire extinguishing agent injected into the connection passage from the inflow passage through the plurality of first opening holes; and a fan discharging the fire extinguishing agent injected into the housing to the outside thereof.

Abstract: The present disclosure provides a secondary battery and a top cover assembly thereof. The top cover assembly includes: a top cover plate and a valve sleeve. The top cover plate includes an accommodation groove and a valve part protruding upward from a bottom wall of the accommodation groove, and the valve part is provided with at least one gas exhaust hole that communicates with an interior of the secondary battery. The valve sleeve is located in the accommodation groove and covers the valve part, a gas exhaust passage that communicates with outside is disposed between the valve sleeve and the valve part, and the gas exhaust passage communicates with the at least one gas exhaust hole.

Abstract: A rechargeable battery protection circuit protects a rechargeable battery, using two NMOS transistors inserted in series in a current path between a battery cathode and a positive terminal connected to load or power terminal of a charger. The protection circuit includes a booster circuit that generates a control voltage, using input capacitances of the NMOS transistors having gates connected to charge and discharge control terminals, respectively. A driving circuit sets the output state of the control terminals to a high level, by supplying the control voltage to the control terminals, a detection circuit detects a battery state and outputs a detection state, and a control circuit operates the driving circuit based on the detection state, so that the output state of the control terminals is selected by the driving circuit to at least one of three states including a high level, a low level, and a high-impedance state.

Abstract: A battery pack including a protective circuit module including a circuit board extending in a first direction, an electrode tab coupling part on the circuit board, and a protection layer between the electrode tab coupling part and the circuit board; and a battery cell including an electrode tab protruding at one end and having a polarity, the electrode tab being coupled to a top surface of the electrode tab coupling part, wherein the electrode tab of the battery cell, the electrode tab coupling part, and the protection layer of the protective circuit module are stacked and coupled in a second direction perpendicular to the first direction.

Abstract: The present application relates to a current collector and a secondary battery. The current collector is used to electrically connect a pole and tab of a secondary battery, and comprises: a first sheet; a second sheet that is disposed to intersect the first sheet, the second sheet being used to electrically connect to the pole; a current collection unit, the current collection unit and the second sheet being disposed at two opposite sides of the first sheet in a first thickness direction thereof, and the first thickness direction thereof intersecting with a second thickness direction of the second sheet; the current collection unit comprises a first current collection sheet, the first current collection sheet is used to electrically connect to the tab, and the first current collection sheet is provided with a first connection terminal that is connected to the first sheet.

Abstract: A vehicle includes an electric machine, a battery, and a controller. The electric machine is configured to deliver power to wheels to drive the vehicle. The battery has an array of cells that are configured to deliver electrical power to the electric machine. The controller is programmed to, in response to a charge imbalance within the array of cells, simultaneously discharge a number of cells within the array based on a temperature of the controller.

Abstract: The disclosure relates to a casing for accommodating battery module and a battery pack. The casing comprises: a housing comprising a bottom plate and a side plate connected to the bottom plate, wherein the bottom plate and the side plate enclose an accommodating space, and the bottom plate is provided with a plurality of recesses opening to the accommodating space; and a buffer assembly comprising at least a first buffer member, which is disposed corresponding to the recess. In the casing for accommodating battery module according to the disclosure, when the battery module is received in the casing, the buffer assembly is located between the battery module and the bottom plate.

Abstract: A battery system includes a pair of current collectors that are configured to provide a parallel electrical connection between electrochemical cells of a cell array. The pair of current collectors includes a first current collector plate that provides an electrical connection between the ends of the respective cells, and a second current collector plate that includes openings that receive the cells therein, and provide an electrical connection between the sidewalls of the respective cells. The current collectors are each on the same end of the cells and the opposed end of the cell can be protected or electrically isolated for a multitude of functions, such as cell cooling.

Abstract: A battery module is disclosed. In one aspect, the battery module includes a plurality of battery cells arranged in a first direction, and a circuit board placed on upper portions of the battery cells. The battery module also includes a bus bar electrically connecting the battery cells and electrically connected to the circuit board, and a pair of end plates respectively positioned at opposite ends of the battery cells in the first direction. The circuit board includes a connector located at one end of the circuit board and exposed to the exterior of the battery module. The connector is configured to be electrically connected to an external device. At least one of the pair of end plates is formed of a metallic material and includes a connector grounding portion enclosing the connector. The circuit board further includes a connection portion connected to the connector grounding portion.

Abstract: An energy storage device for an integrated circuit carrier package. One or more energy storage elements have contact elements arranged thereon that include an anode, a cathode, and an isolated common pad. The energy storage element is configured for arrangement in a stack of energy storage elements in which the isolated common pad is shorted to one of the anode or the cathode by bonded conductive interconnects.

Abstract: A cylindrical battery according to an embodiment of the present invention includes an electrode body, an electrolyte solution, a tubular exterior can that accommodates the electrode body and the electrolyte solution, and a sealing body that is crimped on an opening portion of the exterior can. The sealing body includes a current interrupt mechanism in which a valve member and a metal plate are joined to each other with an insulating plate that includes a circular hollow portion interposed therebetween. The metal plate includes a thin portion that has a circular shape or a C-shape. The hollow portion and the thin portion are concentric with each other when viewed from a direction perpendicular to the metal plate. D1/D2 is no less than 0.56 and no more than 1 where D1 is the diameter of the thin portion, and D2 is the diameter of the hollow portion.

Abstract: A cylindrical battery cell assembly which includes a plurality of cylindrical battery cells arranged so that the cylindrical battery cells having the same polarity face in the same direction, a cell holder configured to confine the cylindrical battery cells as a bundle unit, a first electrode connection member located at an upper portion of the cell holder and a second electrode connection member located at the bottom ends of the cylindrical battery cells. The second electrode connection member includes a second connection portion located at a lower portion of the cell holder and disposed to contact the second electrode terminals. A rod-shaped second terminal portion extends vertically from the second connection portion through an empty space formed inside the cell holder so that one end of the rod-shaped second terminal portion is disposed above the cell holder.

Abstract: The invention relates to a clamping device for clamping a cell stack having multiple battery cells disposed next to each other in a stacking direction (x), wherein the clamping device comprises at least one fastening element for fastening the clamping device to a battery housing, and first and second end plate units, wherein at least the first end plate unit includes an end plate which is firmly connected to the at least one fastening element and a deformation plate. The deformation plate is configured such that the deformation plate can be deformed by a deformation force (F) applied to the deformation plate in the case of a cell stack received in the clamping device when at least one battery cell of the cell stack swells.

Abstract: A battery module including a plurality of battery cells and a cell balancing system having a respective battery cell monitoring module attached to each battery cell and a module carrier having second connection means for connection of a positive terminal of the battery cell to a negative terminal of an adjacent battery cell and for an electrical connection of a negative terminal of the battery cell to a positive terminal of another adjacent battery cell. The battery cell monitoring modules are connected to one another by a balancing bus for transmitting data and electrical current. The electronic battery cell monitoring modules are connected to the positive and negative terminals of the battery cell. The module carrier has two electrical lines and an energy storage module for storing electrical energy. The energy storage module is connected to the two electrical lines to take up or output electrical energy over them.

Abstract: An energy storage device is provided which includes a supercapacitor first electrode, a supercapacitor second electrode, a first electrolyte, a metal electrode, and a hydrophobic layer. The supercapacitor first electrode, the supercapacitor second electrode, and the first electrolyte together form a supercapacitor. The metal electrode is spaced apart from the supercapacitor first electrode to form a first gap, the metal electrode and the supercapacitor second electrode form an Ohmic contact. The hydrophobic layer is located on at least one portion of a surface of the supercapacitor first electrode and/or at least one portion of a surface of the supercapacitor second electrode.

Abstract: A battery pack includes battery cells arranged in a first direction, a wiring board collecting state information about the battery cells, and a sensing portion including an input port through which the state information about the battery cells is input, an output port coupled to the wiring board and through which the state information about the battery cells is output, and a connection portion between the input and output ports. The connection portion extends in a curved shape with portions spaced apart from each other in a second direction crossing the first direction. Damage or dielectric breakdown of a conductive line transmitting signals relating to the state information about the battery cells may be prevented, and accumulation of stress in the conductive line or an insulating film may be prevented, because the conductive line or the insulating film is flexibly deformed in response to swelling of the battery cells.

Abstract: A battery module having first and second cylindrical battery cells, each of the first and second cylindrical battery cells having a negative electrode terminal and a positive electrode terminal, a metal plate configured to connect, in series, the first cylindrical battery cell and the second cylindrical battery cell, a shrinkable tube in which the first and second cylindrical battery cells are mounted, first and second PTC elements respectively provided to the first and second cylindrical battery cells, first insulating members provided between the first and second PTC elements and the shrinkable tube, second insulating members respectively provided between the first and second PTC elements and the first and second cylindrical battery cells, insulating sheets respectively configured to seal an upper surface and a lower surface of the shrinkable tube, and a connection part protruding outward from the shrinkable tube and configured to connect the first and second cylindrical battery cells to an external electro

Abstract: The invention provides a safe multi-directional charger, including a charging portion and a battery portion, wherein the charging portion is provided with a current display and a charging slot, and the battery portion is provided with a battery. The battery is connected with a USB interface and a switch. The bottom of battery portion is provided with a solar panel for power generation, and the shell is equipped with a connecting ring and a hook. The invention can solve the problems of abnormal equipment working and current during charging through current display device and the charging failure without direct connection of power supply through solar panel.

Abstract: A battery pack and a method for manufacturing the same, and more particularly, to a battery pack includes a top cap having a hook protrusion for protecting a PCB connected to a pouch-type battery cell and a method for manufacturing the same.

Abstract: Provided is a plate-shaped battery cell in which electrode leads are located at one side end portion of a battery case including an excess sealing portion of a thermally-welded or adhesive structure for sealing an electrode assembly.

Abstract: The present disclosure relates to a secondary battery and a battery module. The secondary battery includes: a casing including a receiving cavity and an opening which is in communication with the receiving cavity; an electrode assembly housed in the casing; a first top cover plate, which covers the opening and is connected with the casing, the first top cover plate including an insertion portion extending into the casing and an exposed portion disposed outside the casing; and a sealing member; the casing is provided with a first through hole, the insertion portion is provided with a second through hole, the second through hole includes an inlet which is in communication with the first through hole and an outlet which is in communication with the receiving cavity, and the sealing member is connected to the casing and seals the first through hole.

Abstract: A battery pack includes at least two battery cells; a circuit board to control charging and discharging operations of the battery cells; and a connection tab electrically connected to the battery cells, extending towards the circuit board, and including a bent portion proximal to the battery cells and located within a battery area defined by the battery cells. A battery pack suitable for a compact type device is provided and a low-resistive design may be applied to the battery pack.

Abstract: A battery module includes a number of battery cells, which are connected to each other at connection poles. The battery cells have respective hard shell housings, in which at least one bus bar extends. A number of wound and/or stacked battery cells is electrically contacted by the at least one bus bar.

Abstract: The present disclosure provides a battery module and a protecting assembly thereof. The protecting assembly comprises a base and an upper cover. The base is fixed to an end plate, a receiving cavity is formed between the upper cover and the base. An outputting electrode piece extends into the receiving cavity. The base comprises a basic body and a first side plate, the first side plate extends from the basic body, the basic body are provided with first grooves. The upper cover comprises a top wall, a first side wall extending downwardly from the top wall, a second side wall extending downwardly from the top wall and a limiting wall extending downwardly from the second side wall and inclined. The limiting wall is inserted into the first groove, the first side wall latches with the first side plate.

Abstract: The present disclosure provides a secondary battery, which comprises an electrode assembly, a case and a cap assembly. The electrode assembly comprises a first electrode member, a second electrode member and a separator. The case has an opening and receives the electrode assembly. The cap assembly comprises a cap plate and a first electrode terminal, the cap plate covers the opening of the case; the cap plate has an electrolyte injection hole. The first electrode member comprises a main portion, a first protruding portion and a second protruding portion, the first protruding portion is connected with an end of the main portion close to the cap plate, the second protruding portion connects the first protruding portion and the first electrode terminal. The first protruding portion extends to a lower side of the electrolyte injection hole, and a first end of the first protruding portion is beyond the second protruding portion.

Abstract: The present invention relates to a band assembly including a first outer connecting portion and a second outer connecting portion disposed to face each other, wherein the first outer connecting portion includes a first fastening hole and the second outer connecting portion includes a third fastening hole, an inner connecting portion disposed between the first outer connecting portion and the second outer connecting portion, wherein the inner connecting portion includes a second fastening hole that corresponds to the first fastening hole and the third fastening hole, and a rechargeable battery inserted into the first fastening hole, the second fastening hole, and the third fastening hole to connect the first outer connecting portion, the inner connecting portion, and the second outer connecting portion.

Abstract: The disclosure relates to a battery pack, comprising a casing; a built-in circuit disposed inside the casing; a consumable component disposed inside the casing and connected in series to the built-in circuit, wherein an opening corresponding to the consumable component is provided on the casing; a safety switch disposed inside the casing, wherein an on/off of the safety switch controls a connection/disconnection of the built-in circuit; and a cover body disposed corresponding to the opening, wherein the cover body has a first state in which the cover body is capped at the opening, so that the safety switch is switched on and the built-in circuit is connected, and a second state in which the cover body is detached from the opening, so that the safety switch is switched off and the built-in circuit is disconnected.

Abstract: Disclosed is a battery module, which includes a base plate; a plurality of battery cells disposed on the base plate; a plurality of sockets electrically connected to electrode leads of the battery cells; and a plurality of connecting bars configured to be inserted into a part of the plurality of sockets to allow the plurality of battery cells to be connected in a serial pattern or a combined serial and parallel pattern.

Abstract: A self-charging supercapacitor is provided which includes a supercapacitor first electrode, a supercapacitor second electrode, a first electrolyte, and a metal electrode. The supercapacitor first electrode and the supercapacitor second electrode are parallel to and spaced apart from each other. A part of the metal electrode is Ohmic contacted with a surface of the supercapacitor second electrode, and another part of the metal electrode is disposed opposite to the supercapacitor first electrode.

Abstract: A method for charging self-charging supercapacitor includes: providing a self-charging supercapacitor which includes a supercapacitor first electrode, a supercapacitor second electrode, a first electrolyte, and a metal electrode; the metal electrode and the supercapacitor second electrode form an Ohmic contact, the metal electrode is spaced apart from and opposite to the supercapacitor first electrode. Electrically connecting the metal electrode and the supercapacitor first electrode with a second electrolyte.

Abstract: Productivity of an assembled battery is improved by shortening the takt time for assembly. An assembled battery (100) includes a battery module group (B) including one or more battery cells (150) and a cell holder (120) for holding the one or more battery cells (150), and an auxiliary module group (S) including components (210, 220, 230, 240) and a pedestal (200) on which the components (210, 220, 230, 240) are arranged. The battery module group (B) and the auxiliary module group (S) are attached together by the pedestal (200) being fastened to the cell holder (120) with bus bars (164, 165, 285, 286).

Abstract: A self-charging supercapacitor is provided which includes a supercapacitor first electrode, a supercapacitor second electrode, a first electrolyte, and a metal electrode. The supercapacitor first electrode and the supercapacitor second electrode are parallel to and spaced apart front each other. The metal electrode and the supercapacitor second electrode form an Ohmic contact, the metal electrode is spaced apart from and opposite to the supercapacitor first electrode.

Abstract: A flow battery includes: a first liquid containing dissolved therein a condensed aromatic compound and lithium; a first electrode immersed in the first liquid; and a first circulator including a first container and a first passage prevention member. The first liquid containing the condensed aromatic compound dissolved therein has the property of causing the lithium to release solvated electrons and dissolve as cations. When the lithium dissolved in the first liquid precipitates on the first electrode, lithium precipitate particles are generated. The first circulator circulates the first liquid between the first electrode and the first container. The first circulator transfers the lithium precipitate particles generated on the first electrode to the first container. The first passage prevention member is disposed in a channel through which the first liquid flows from the first container to the first electrode. The first passage prevention member prevents passage of the lithium precipitate particles.

Abstract: A battery pack includes a plurality of battery modules stacked with connecting terminals disposed at predetermined positions, a holding unit for holding the plurality of battery modules under the stacked state, a plurality of conducting paths connecting corresponding connecting terminals, and a substrate connected to the holding unit. The plurality of conducting paths are provided integrally in the substrate and disposed to connect the corresponding connecting terminals in association with connection of the substrate to the holding unit.

Abstract: The present invention refers to a battery system (300) which comprises a cell stack (20), wherein at least two battery cells (10) of the cell stack (20) are electrically interconnected via a battery cell connector (90). The battery system (30) comprises a printed circuit board, PCB (150), and a cell connecting unit, CCU (140). The battery cell connector (90) is accommodated in the CCU (140), the CCU (140) being fixed onto the cell stack (20) and comprising one first flexible bracket (145) that is inserted into a corresponding mounting hole (151) of the PCB (150). According to the invention, the first flexible bracket (145) of the CCU (140) comprises a member (146) configured to fix the PCB (150) to the CCU (140) after the member (146) has been molten in a state in which the first flexible bracket (145) was inserted into the corresponding mounting hole (151).

Abstract: A wearable battery pack is provided. The wearable battery pack includes a battery pack body, a battery cell and a housing accommodating a battery cell and a wearable device capable of wearing so that the battery pack body at least be worn on a user's back. The battery pack body has a heat dissipation channel running through one side of the battery pack body to the opposite side; the side of the battery pack body which is penetrated by the heat dissipation channel is located between the back of the user and the other side when the user carries the battery pack body. The invention provides a wearable battery pack that can be carried by users. The wearable battery pack has achieved good heat dissipation performance and can be carried by users comfortably.

Abstract: The present disclosure provides a thermal runaway detection circuit and a method, which is directed to field of batteries. The circuit includes: a sensing module including a terminating resistor; a detection module including a first voltage dividing resistor set and a second voltage dividing resistor set; and a processing module connected to the detection module, wherein the processing module is configured to obtain thermal runaway detection data, and determine whether thermal runaway occurs in the battery pack based on the thermal runaway detection data. The thermal runaway detection data includes first sampled data and second sampled data. The technical solutions in the present disclosure can improve safety of the battery pack.

Abstract: An electronic module includes wireless data transmission circuitry configured to receive from a base station a signal corresponding uniquely to a battery device, wireless charging circuitry coupled with the wireless data transmission circuitry and configured to receive energy wirelessly transmitted from the base station, and a controller configured to, in response to the wireless data transmission circuitry receiving the signal, cause the wireless charging circuitry to charge a battery module of the battery device corresponding to the signal using the received wirelessly transmitted energy.

Abstract: In a battery wiring module that is attached to a unit cell group, a configuration that can inhibit noise propagation to signal lines is implemented in a more compact manner. A battery wiring module is attached to a unit cell group in which a plurality of unit cells are aligned. The battery wiring module includes: a wiring pattern configured as a signal transmission path on one side of a board main body portion; and a guard pattern that is formed in the vicinity of the wiring pattern on the one side of the board main body portion, and is kept at a predetermined reference potential while being insulated from the wiring pattern.

Abstract: The invention is directed towards an indicator circuit. The indicator circuit includes a ground plane; an antenna; a decoupler component; and an integrated circuit. The antenna includes at least one antenna trace; a first antenna terminal; and a second antenna terminal. The decoupler component includes a first decoupler component terminal and a second decoupler component terminal. The integrated circuit is electrically coupled to the first antenna terminal and the second antenna terminal. The integrated circuit is electrically coupled to the first decoupler component terminal. The second decoupler component terminal is electrically connected to the ground plane.

Abstract: According to one embodiment, provided is a nonaqueous electrolyte battery that includes a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte. The separator is disposed between the positive electrode and the negative electrode. The separator includes a fiber-made nonwoven fabric having a tortuosity of 1.8 to 3 and a vacancy of 40% to 60%. The negative electrode has an operating potential of 0.7 V or more with respect to the potential of metallic lithium.

Abstract: A wiring module includes a plurality of bus bars for connection to positive and negative electrode terminals of a plurality of electricity storage elements; a plurality of detection wires electrically connected the bus bars to detect a state of the electricity storage elements; a plurality of overcurrent protection elements connected between the plurality of bus bars and the plurality of detection wires; and an insulating protector in which the plurality of bus bars, the plurality of detection wires, and the plurality of overcurrent protection elements are disposed, wherein the insulating protector includes a bus bar arrangement portion in which the bus bars are disposed, and a plurality of extension portions which are extended to a region different from the bus bar arrangement portion and in which the overcurrent protection elements are disposed, and the plurality of extension portions are stacked in a plurality of levels.

Abstract: A method for abnormality detection in an energy unit includes passively detecting an abnormality in an energy unit by detecting electromagnetic radiation generated by the abnormality, the energy unit comprising at least one of an electrical energy unit and an electrochemical energy unit. A method for detecting an abnormality in an energy unit includes (a) applying a signal to the energy unit, (b) performing a plurality of measurements, at a respective plurality of different locations within the energy unit, of a response of the energy unit to the signal, and (c) processing the plurality of measurements to identify the abnormality.

Abstract: A battery packaging assembly having safety features that reduce the risk of thermal propagation is disclosed. The battery packaging assembly may include a foam layer having a plurality of cutout trenches, the foam layer configured to engage battery cells in a press-fit relationship. In addition, the battery packaging assembly may include a tray configured to receive the foam layer, the tray enclosing a compartment configured for receiving a plurality of battery cells. Further, the battery packaging assembly may include a ventilation cavity in fluid communication with the plurality of trenches of the foam layer.