Abstract: According to one embodiment of the present invention, a lithium ion battery having desirable safety performance is provided. The lithium ion battery includes a battery housing, a battery cover assembled to the battery housing, a pressure relief valve coupled to the battery housing and/or battery cover, and a safety device formed on the housing and/or battery cover and fixed to the pressure relief valve. The safety device includes a shielding plate facing the pressure relief valve, a side wall and an air flow channel structure. The side wall extends from the shielding plate and connects with the battery housing or the battery cover. The air flow channel structure is defined in the side wall.

Abstract: A rechargeable battery includes a case accommodating an electrode assembly; a cap plate coupled to the case and having a short-circuit hole; a first electrode terminal and a second electrode terminal extending through the cap plate and electrically connected to the electrode assembly; a membrane fixed to the cap plate in the short-circuit hole and configured to electrically connect the first electrode terminal and the second electrode terminal to cause a short circuit; a connection plate electrically connected to the first electrode terminal and spaced from a side of a short-circuit member; a top insulating member located between the connection plate and the cap plate; and a fixing member fixed to the cap plate and supporting the top insulating member.

Abstract: Disclosed is a frame for a secondary battery, which has an improved structure to prevent a cooling plate from being deformed or distorted due to shrinkage of a main frame. The frame for a secondary battery includes a cooling plate made of a thermally conductive material with a plate shape, and a main frame having a plurality of unit frames spaced apart from each other in a horizontal direction by a predetermined distance, the main frame being configured to surround a rim of the cooling plate and made of a material different from the cooling plate.

Abstract: The present invention relates to a battery module mounted with an overcharge preventing device, and an overcharge preventing device for a battery module. The battery module mounted with an overcharge preventing device of the present invention includes: a battery cell including a first battery cell and a second battery cell, which are spaced apart from each other; and an overcharge preventing device inserted and disposed between the first battery cell and the second battery cell, and configured to block power supplied to the battery cell when the battery cell is expanded according to overcharge, in which the overcharge preventing device is configured as one module separately from the battery cell, and is replaceably disposed between the first battery cell and the second battery cell, which are spaced apart from each other.

Abstract: A non-aqueous electrolyte secondary battery includes an external electrode terminal, a current collecting tab, a lead, and first and second insulating members. The lead has a hollow portion, electrically connecting the external electrode terminal and the diaphragm. The diaphragm is placed to cover the hollow portion and allow the diaphragm to deform toward the hollow portion. The first insulating member is interposed between the sealing plate and the lead. The second insulating member is interposed between the diaphragm and the current collecting tab. Side walls of the first insulating member and side walls of the second insulating member are coupled to each other. The battery is configured such that the diaphragm deforms toward the outside of the battery when a gas pressure increases in the battery, thereby breaking an electric connection between the external electrode terminal and an electrode assembly of the battery.

Abstract: Provided is a battery, and more particularly, a battery in which a cutting unit is formed in a seating groove so that the cutting unit and a sub battery module do not contact each other in a normal operation state, such that the battery may be stably driven, and a pouch of the sub battery module may be cut by the cutting unit only in an abnormal operation state such as over-charging, over-discharging, exposure to a high temperature, an electric short circuit, or the like, to prevent ignition or explosion in advance, such that safety may be improved.

Abstract: A rechargeable battery includes an electrode assembly including a first electrode, a second electrode, and a separator between the first electrode and the second electrode. The rechargeable battery also includes a case accommodating the electrode assembly. The rechargeable battery further includes a cap plate including a first plate and a second plate coupled to the first plate along a joint. The cap plate is coupled to an opening of the case. The rechargeable battery also includes a vent unit at the joint where the first plate of the cap plate is coupled to the second plate.

Abstract: A reverse-acting rupture disc (10) having a laser-defined reversal initiation feature (16) is provided in the bulged section (12) of the disc. The reversal initiation feature comprises at least a first lased area (22) that has a reduced thickness relative to rest of the bulged section. A second lased area (24) may also be provided within the margins of the first lased area. The second lased area has a depth that is greater than the depth of the first lased area. A line of weakness (40) may be formed in the bulged section that functions to direct reversal of the bulged section toward a particular area of the disc, such as line-of-opening recess (56).

Abstract: An apparatus comprises a rechargeable battery susceptible to thermal runaway, and a metal enclosure for the battery. The enclosure is configured to mitigate battery failure consequences resulting from thermal runaway.

Abstract: A rechargeable battery is provided. The rechargeable battery includes a case, an electrode assembly in the case, a cap plate sealing an opening of the case, and a terminal portion attached to the cap plate. The terminal portion includes a terminal plate on the cap plate and electrically connected to the electrode assembly, and an auxiliary plate electrically connecting the cap plate to the terminal plate. The auxiliary plate has a plurality of openings for reducing a current flow along a short circuit current path.

Abstract: A battery pack comprising: a secondary battery including a safety valve; a gas absorption portion including a gas absorbent represented by zeolite and a container hermetically enclosing the gas absorbent; and a case housing the secondary battery and the gas absorption portion. The safety valve is configured to discharge a gas produced in the secondary battery at the time of abnormality. The container includes a principal surface facing the safety valve, for example, and when the gas is discharged, the container is unsealed by rupturing of at least the principal surface of the container by an effect of heat or pressure of the gas.

Abstract: Provided is a secondary battery including an electrode assembly, a case accommodating the electrode assembly, and a cap assembly, including a cap plate having a short-circuit hole, configured to seal the case. The secondary battery includes a first connection plate at an exterior surface of the case and coupled to the electrode assembly, a capacitive member between the first connection plate and the cap plate, and a short-circuit unit including an inversion plate positioned in the short-circuit hole, and a second connection plate at an exterior side surface of the case spaced apart from the cap plate and extending over at least a portion of the short-circuit hole, the second connection plate being coupled to the electrode assembly.

Abstract: In a system and method for detecting venting of a sealed storage cell, the sealed storage cell comprises a container with a sealing cap adapted to be detached from the container and move in the presence of gas overpressure inside the container to allow venting of the storage cell. The detection system comprises a printed circuit board with a central portion designed to be situated opposite the sealing cap, a peripheral portion surrounding the central portion and connected to the central portion by a hinge adapted to flex during movement of the sealing cap, and at least one frangible portion adapted to break upon movement of the sealing cap. An electrical printed track connects the peripheral portion to the central portion through the hinge and frangible portion(s), and is designed to be broken upon breaking of the frangible portion(s) following movement of the sealing cap.

Abstract: A rechargeable battery includes: an electrode; a case accommodating the electrode assembly therein; a cap plate closing an opening of the case; a first electrode terminal and a second electrode terminal extending through the cap plate and coupled to the electrode assembly; and an external short-circuiter including a membrane closing and sealing a short-circuit opening in the cap plate and coupled to the second electrode terminal, and a short-circuit tab coupled to the first electrode terminal and separated from the membrane, wherein the cap plate includes a bending inducement groove formed at the second electrode terminal.

Abstract: A prismatic secondary battery includes a prismatic hollow outer body having a mouth and a bottom; a flat electrode assembly, a positive electrode collector, a negative electrode collector, and an electrolyte, all of which are stored in the prismatic outer body; a sealing plate sealing up the mouth of the prismatic outer body; and a positive electrode terminal attached to the sealing plate in an electrically insulated manner. The sealing plate includes a gas release valve and an electrolyte pour hole and further includes, on the front face, a concaved flat face having an identification code. With the prismatic secondary battery of the invention, a jig for assembly or the like is unlikely to come into contact with the identification code during an assembly process of the prismatic secondary battery, hence the identification code is unlikely to be abraded, and the traceability is unlikely to be lost.

Abstract: An automotive battery module with one or more battery cells and a heat exchange member placed in thermal communication with the battery cell. Heat generated within the battery cell by, among other things, electric current that can be used to provide motive power for the automobile may be removed by the heat exchange member that is made up of a flexible substrate and one or more graphene layers disposed on the substrate. The construction of the substrate and graphene layer is such that multiple heat transfer paths are established, each defining different levels of thermal conductivity and related transfer of heat away from the battery cells.

Abstract: A rechargeable battery includes a case, an electrode assembly in the case, a terminal electrically connected to the electrode assembly, and a cap assembly sealing the case. The cap assembly includes a cap plate having a short circuit opening and a short circuit plate in the short circuit opening. The terminal includes a collector plate connected to the electrode assembly, a collector terminal connected to the collector plate and penetrating the cap plate, and a fastening terminal spaced apart from the cap plate. The fastening terminal includes a fastener engaged with the collector terminal, and an extender extending from the fastener. The extender is adjacent to the short circuit plate. The cap assembly also includes an insulation member between the cap plate and the fastening terminal, and a cover covering the extender.

Abstract: The present invention provides a battery case configured by fixing a joined portion where plate sections overlap with each other using a fixation member, and two different types of sealing members are disposed at the joined portion. It is possible to ensure high sealing properties by using sealing members suitable for the respective shapes of portions of the joined portion.

Abstract: A secondary battery includes an electrode assembly having a first electrode plate, a second electrode plate and a separator interposed between the first and second electrode plates; a lower case accommodating the electrode assembly therein; and a cap assembly sealing the lower case. In the secondary battery, the lower case has the electrode assembly and a vent portion, and includes a surface facing the cap assembly. The vent portion includes an intersecting portion formed inside the surface, first and second curved portions curved to extend from the intersecting portion, and an extending portion extended in a straight line from the intersecting portion. The thickness of the intersecting portion includes the minimum thickness of the surface.

Abstract: A battery assembly including a frame including a pair of side plates that include a plurality of guide grooves and a bottom plate connected to the side plates; a plurality of barriers each including a pair of side panels, a lower panel, an upper panel, a plurality of protrusions that are protruded from the side panels, and a dividing panel, wherein the plurality of protrusions are inserted into the plurality of guide grooves to slidably move along the guide grooves upon being mounted on the frame, and a plurality of batteries that are respectively accommodated by the barriers, wherein the barriers are stacked such that the dividing panels of the adjacent barriers face one another.

Abstract: A device for aiding in the fracture of a vent of an electrochemical cell includes a main body having a first surface and a plurality of lobes extending out from the first surface of the main body such that an open space is provided between adjacent lobes. Each of the plurality of lobes are configured to make contact with the vent during deployment of the vent such that the vent completely separates from a bottom of the electrochemical cell. The open space provided between adjacent lobes is configured to allow gases from inside the electrochemical cell to pass through during deployment of the vent.

Abstract: A secondary battery includes a case configured to accommodate an electrode assembly, a safety vent on a first side of the case, and a film unit disposed on the first side of the case, the film unit including a first film unit covering at least a part of the safety vent, the first film unit including a break unit, and a second film unit extending from the first film unit, the second film unit being adhered to the case.

Abstract: A rechargeable battery including: an electrode assembly including a first electrode and a second electrode; a case containing the electrode assembly; a cap plate coupled to the case; a short-circuit tab electrically connected to the first electrode; and a short-circuit member electrically connected to the second electrode and configured to contact the short-circuit tab according to an increase of an internal pressure of the rechargeable battery, and the short-circuit member includes a connection portion having a plate shape, a support portion at an outer side of the connection portion, and a variable groove having a shape that is configured to change according to the increase of the internal pressure.

Abstract: A hermetically-sealed battery including a case body made of a metal, power generation elements housed in the case body, and a lid plate made of a metal. The case has an opening. The lid plate is fitted into the opening of the case body. The lid plate has a periphery laser-welded together with the case body to hermetically seal the opening of the case body with the lid plate. The lid plate includes a frame piece integrally provided along the periphery of the lid plate so as to be perpendicular to a plane surface of the lid plate. The frame piece is pressed into the opening along an inner wall surface. Laser welding is performed along a boundary between the frame piece and the inner wall surface that are in pressure contact with each other.

Abstract: A curved container for electrochemical battery cells manufactured with an open side into which the battery cells are placed along with a resilient structure such that when the lid is placed on the container and attached/sealed, the battery cells are sealed in the container and preloaded against the large top and bottom surfaces of the container. Electrical contacts feed through one edge of the container to enable the electrical power generated by the cells to be safely accessed, and the cells can be safely charged without external atmospheric leaks into the container, or gases generated during battery use to escape. The containers can be stacked on edge next to each other as a stack but without the need to compress the stack to maintain battery cell compression, which enables a container to be easily replaced without having to dissemble the stack.

Abstract: In a power supply device, the gas exhaust valve is integrally coupled to the outer can at the time of opening the gas exhaust valve, and the connecting portion between the outer can and the gas exhaust valve is partially broken at the time of opening the gas exhaust valve by an internal pressure of the outer can, and the gas duct further comprises a joining aperture being connected airtight to the gas exhaust valve, and a duct exhaust portion being connected to the external gas exhaust duct, and the inner diameter d inside the gas duct is at least partially smaller than the outer diameter a of the gas exhaust valve between the joining aperture and the duct exhaust portion.

Abstract: A rechargeable battery includes an electrode assembly including electrodes both sides of a separator; a case accommodating the electrode assembly; a cap plate coupled to an opening of the case; an electrode terminal assembled to a terminal hole of the cap plate; an insulator between the electrode terminal and a first surface of the cap plate; a gasket between the electrode terminal and a second surface of the cap plate; and a lead tab at one side of the gasket to connect the electrode terminals to the electrode assembly. The electrode terminal and the cap plate form a vent hole that penetrates the electrode terminal and the cap plate, and the vent hole is sealed by a vent plate.

Abstract: A battery includes: an electrode stacked body; a battery case that accommodates the electrode stacked body; positive and negative electrode terminals that are provided so as to communicate inside and outside of the battery case with each other; a lead that electrically connects tabs of the electrode stacked body to the electrode terminals; and an insulated lead insulating cover in which a space is formed so that the lead enters and a terminal through-hole is formed so that one end of the electrode terminal enters the space therethrough. An insulated lead insulating cover includes a first cover component and a second cover component that cooperatively form the space and the terminal through-hole with each other, and the first cover component and the second cover component respectively include engagement portions engaging removable with each other.

Abstract: A rechargeable battery including an electrode assembly; a case housing the electrode assembly; a cap assembly including a cap plate having a short-circuit hole and sealing an opening of the case; and a short-circuiting member including a short-circuiting plate arranged at the short-circuit hole and a connection plate covering at least a portion of the short-circuit hole at an exterior side, the connection plate being spaced apart from the cap plate and electrically connected to the electrode assembly, and the case and the cap assembly are electrically insulated from the electrode assembly.

Abstract: A device for the accumulation of electrical energy contains a gas-electric battery having a hollow housing, partially filled with an electrolyte solution, and electrodes, positioned inside the hollow housing and made of a conductive adsorbent of the electrolysis gases. The electrodes are divided by a gas-permeable separator. Current-collectors linked to the electrodes are connected to a charge-discharge converter designed to allow for a periodic change in the polarity of the charge current during the charging process. The device makes it possible to provide a long operating life with minimal environmental pollution.

Abstract: A secondary battery, in which working pressure and rupture pressure of a safety vent are effectively controlled with respect to a slope of the safety vent and shapes of rupturable grooves. The secondary battery includes an electrode assembly arranged within a can, a cap assembly coupled to the can and including a lower portion arranged above the electrode assembly and having a through-hole arranged at a center thereof, a safety vent electrically connected to the electrode assembly through the through-hole and an insulator arranged between the safety vent and the lower portion of the cap assembly, wherein a first distance between a portion of the safety vent arranged at a region near the through-hole and the lower portion of the cap assembly is smaller than a second distance between a portion of the safety vent positioned furthest from the through-hole and the lower portion of the cap assembly.

Abstract: A battery module having sealed vent chamber includes a plurality of electrochemical cells each having a vent at an end thereof. The module also includes a structure defining a chamber and comprising a plurality of sockets, each socket configured to receive one of the plurality of electrochemical cells such that the vents of the electrochemical cells are located in the chamber. The module further includes a seal provided between at least one of the electrochemical cells and its associated socket. At least a portion of the seal is deformable such that gases released from the electrochemical cells into the chamber compress the deformable portion of the seal against the electrochemical cells to seal the gases in the chamber.

Abstract: A battery cell is provided. The battery cell includes a battery case, an electrode assembly located in the battery case, the electrode assembly comprising a cathode, an anode, and a separator disposed between the cathode and the anode, an electrolyte present in the battery case, the battery case being sealed at a perimeter thereof, and a frame coupled to the perimeter of the battery case, the frame having a venting guiding portion at the perimeter of the battery case, such that sealing of the battery case is released through the venting guiding portion when internal pressure of the battery cell increases, the venting guiding portion comprising a reduction in the amount of material of the frame in a predetermined location at the perimeter of the battery case. A battery cell module is also provided.

Abstract: A rechargeable battery according to the present invention includes an electrode assembly that includes a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode, a case that contains the electrode assembly and a cap assembly that is connected to the case. The positive electrode includes a current collector and a positive active material layer that includes an NCM-based positive active material disposed at the collector. The cap assembly includes a vent plate having a notch, and a current interrupt portion that interrupts electrical connection in a case of an increase in pressure inside the case. When a current interrupt pressure of the current interrupt portion is “A,” a vent fracture pressure at which the vent plate fractures at the notch is “B,” and the capacity of the rechargeable battery is “X,” they satisfy a formula of A/B=1.22?0.39X+D (?0.08?D?0.08).

Abstract: The present invention relates to a battery pack capable of discharging gases in a pouch type battery cell when a gas pressure inside the pouch type battery cell is increased over a reference pressure, the battery pack including: a plurality of pouch type battery cells; a case comprising partitions suppressing the pouch type battery cells from expanding in a thickness direction thereof, wherein the pouch type battery cells are respectively held in spaces defined by the partitions; and a punching unit installed on the case to pierce a portion of surfaces of the pouch type battery cells , which is not supported by the partition, and having pin members of which number is equal to that of the pouch type battery cells.

Abstract: A battery module including a plurality of battery cells aligned in one direction, the plurality of battery cells each having a vent on a top surface thereof; and at least one vent cover covering the vent and covering side surfaces of the plurality of battery cells, wherein one vent cover covers outer side surfaces of outermost battery cells among the aligned plurality of battery cells, or a plurality of vent covers cover side surfaces of a battery cell of the plurality of battery cells.

Abstract: A high-reliability prismatic secondary battery with a current interruption mechanism that is unlikely to be damaged even if the battery is subjected to shock is provided. The prismatic secondary battery includes a second insulating member having a first through-hole, the second insulating member being arranged between a first region of a positive electrode collector and an inversion plate. The first region of the positive electrode collector and the inversion plate are electrically connected to each other through the first through-hole. The second insulating member has a plurality of fixing pawl portions. The fixing pawl portions are hooked and fixed to a fixing portion formed on the outer surface side of the conductive member.

Abstract: A current interruption mechanism for prismatic secondary battery includes a tubular conductive member electrically connected to a positive electrode external terminal, an inversion plate, and a positive electrode collector connected to the inversion plate. The positive electrode collector has a first region that is parallel to a sealing body and a second region that is connected to a positive electrode plate. The boundaries between the first and second regions are disposed further outward than the inner surface of the tubular conductive member, and at least one of the edge portions, other than the boundaries between the first region and second region, is located further outward than the inner surface of the tubular portion of the conductive member. The current interruption mechanism is unlikely to be damaged even if the battery is subjected to shock due to vibration, falling, etc.

Abstract: An electrode lead for electrically connecting an electrode assembly provided inside a case of a secondary battery with the outside of the case, according to the present invention, comprises: an inner lead which is inserted between sealing parts of the case and to which an electrode tab of the electrode assembly is attached, and which has a gas flow path so as to allow gas to flow between the inside and the outside of the case; and an external lead which is insertably disposed in the gas flow path, is electrically connected with the inner lead when inserted into the gas flow path, seals one end of the gas flow path, and is separated from the gas flow path so as to cut off electrical connection with the inner lead when the pressure of the gas flowing into the gas flow path is greater than or equal to the predetermined pressure.

Abstract: A battery module includes a plurality of cells and a plurality of holders. The plurality of cells are parallelly arranged in a row at intervals. The plurality of cells have explosion-proof valves which are provided therein and which are capable of opening upon an increase in an inner pressure in the plurality of cells. The plurality of holders are arranged among the cells so as to hold the cells. The holders have holder pieces which are integrally formed therein and which cover at least part of the explosion-valves so as to prevent emissions from the explosion-proof valves from being released in all directions.

Abstract: The present disclosure relates to a cylindrical lithium ion secondary battery, which can prevent a cylindrical can from being cracked due to an external shock applied during an assembling process while controlling a rupture pressure of the cylindrical can. The cylindrical lithium ion secondary battery includes a cylindrical can, an electrode assembly accommodated in the cylindrical can with an electrolyte, and a cap assembly sealing the cylindrical can, wherein the cylindrical can has a cylindrical bottom portion and a side portion extending from the bottom portion to the cap assembly, and a safety vent having a thickness gradient is formed on the bottom portion.

Abstract: Electrical energy storage device for powering portable devices such as vehicles or consumer electronics includes barriers to minimize migration of thermal energy and propagation of combustion in the rare event that electrical energy storage cells fail, burst and ignite. A burst structure is provided to vent gas from the device in a desired direction in the event pressure within the device exceeds a maximum value. Biased vents permit gases emanating from a portable electrical energy storage cell within an electrical energy storage module to escape and isolate other electrical energy storage cells from the gases.

Abstract: There is a provided a secondary battery capable of preventing unloading and rotating caused by possible vibration or shock by increasing a coupling force among the vent plate, the insulator, and the cap-down that compose the cap assembly of the secondary battery. To increase the coupling force among the vent plate, the insulator, and the cap-down, protrusions and corresponding grooves or holes, and grooves with step areas may be formed. Alternatively, a plurality of insulators may be formed in a divided form. A secondary battery with a reliable cap assembly can be implemented through such a structural change.

Abstract: An apparatus, system, and method are disclosed for battery venting containment that include a battery enclosure configured to contain emissions from one or more battery cells within the enclosure upon a rupture of a case of the one or more battery cells. The battery enclosure includes a first side of the battery enclosure configured to expand upon rupture of the case of the one or more battery cells within the enclosure and a second side of the battery enclosure configured to be rigid.

Abstract: An electrochemical cell includes a housing having a first end and a vent located at the first end that is configured to deploy from the housing to allow the expulsion of gases from within the cell. The electrochemical cell also includes at least one projection extending outward from the first end adjacent the vent. The at least one projection is configured to prevent accidental deployment of the vent.

Abstract: A system includes a vent housing configured to be installed on a lower housing of a battery module at a first side of the vent housing. The vent housing has a main body having an opening on a second side of the vent housing and an internal chamber coupled to the opening. The internal chamber includes a first wall having an internal burst vent configured to open at a first pressure threshold and a second wall having a ventilation vent comprising a gas-selective permeability layer.

Abstract: A rechargeable battery includes an electrode assembly including a first electrode, a second electrode, and a separator between the first electrode and the second electrode. The rechargeable battery also includes a case accommodating the electrode assembly. The rechargeable battery further includes a cap plate including a first plate and a second plate coupled to the first plate along a joint. The cap plate is coupled to an opening of the case. The rechargeable battery also includes a vent unit at the joint where the first plate of the cap plate is coupled to the second plate.

Abstract: A cylindrical lithium secondary battery includes an anode and a cathode, capable of occluding or emitting lithium ions; a non-aqueous electrolyte; and a CID (Current Interrupt Device) for intercepting electric current and lowering inner pressure when the inner pressure of the secondary battery is increased. The cylindrical lithium secondary battery may ensure the safety of the battery with respect to overcharging and also at the same time prevent the problem wherein the CID is activated too early, such that the battery stops its operation when the battery is used in a high-temperature environment.

Abstract: A sealed battery (10) provided by the present invention includes: a current cut-off valve (22); and a connecting member (30) having an engagement hole (34) formed in a location adjacent to the current cut-off valve. The current cut-off valve is conductively connected to the connecting member by joining linearly to a peripheral edge of the engagement hole and/or joining at a surface that is in contact with an inner wall of the engagement hole in a state in which part of the current cut-off valve is fitted into the engagement hole. When an internal pressure of a battery case (40) rises above a predetermined level, the current cut-off valve is deformed outward of the case by the internal pressure, the current cut-off valve is separated from the connecting member, and the electric connection between the connecting member and the current cut-off valve is broken.

Abstract: A secondary battery having no beading portion includes an electrode assembly having a cathode plate and an anode plate arranged with a separator being interposed therebetween, a battery case having an upper can configured to accommodate the electrode assembly and an electrolytic solution in an inner space thereof and have an open top and an open bottom, the top of the upper can being bent inwards, and a lower sealing member coupled to the bottom of the upper can to seal the bottom of the upper can, and a cap assembly having a top cap protruding on an uppermost portion thereof to form a cathode terminal, a safety vent located below the top cap and configured to change a shape when an inner pressure of the battery case increases, and a gasket surrounding rims of the top cap and the safety vent.