Patent Description:
With the rapid development of new energy vehicles and the practicalization of superfast charging technology, a cooling method of power battery has been upgraded from air cooling to liquid cooling. Furthermore, full immersion oil cooling has also entered the visions of automobile manufacturers. The fully immersed oil cooling is able to bring out the performances of high performance battery cells, prolong service life of the battery cells, and perfectly solve the problems of thermal runaway and failure propagation, and thus has attracted a large number of people's interests due to its extremely high heat exchange efficiency, uniform temperature distribution, and extremely strong passive thermal safety. It is found that steel beads which are most frequently used to be squeezed into the electrolyte injection hole for sealing is of a possibility of falling out or causing an electrolyte leakage under an extreme temperature condition due to different material expansions rate.

It should be noted that the aforesaid information disclosed in the background is only intended to enhance the interpretation of the background of the present application and thus may include information that does not constitute as prior art known to one of ordinary skill in the art. The prior art <CIT>, <CIT> and <CIT> discloses secondary batteries with bursting means to avoid explosions.

One objective of the embodiments of the present application is to provide a battery cell and a battery that aim to solve the technical problem that steel beads which are most frequently used to be squeezed into the electrolyte injection hole to seal the electrolyte injection hole, and is of a possibility of falling off or leaking electrolyte under extreme temperature conditions due to the different material expansion rates.

In order to achieve the aforesaid objective, the technical solutions adopted in the present application are as follows: a battery cell is provided, the battery cell includes:.

One side of the cover plate facing the first current collector is provided with first bursting line(s) which is/are shaped as groove structures.

In some embodiments, the first current collector is provided with an inner side and an outer side which are opposed to each other, the inner side of the first current collector is connected to the spiral-wound cell, and the cover plate is connected to the outer side of the first current collector; the inner side of the first current collector faces the spiral-wound cell, and is provided with a plurality of second bursting lines, and the plurality of second bursting lines are shaped as groove structures.

In some embodiments, the number of the second bursting lines is plural and the plurality of the second bursting lines are arranged to be spaced apart around a circumference of the electrolyte injection hole in distribution.

In some embodiments, the first current collector is arranged at an anode of the spiral-wound cell, the electrolyte injection hole is arranged at a center of the first current collector, the outer side of the first current collector is provided with an accommodation cavity recessed from one end of the spiral-wound cell to the other end of the spiral-wound cell, and the cover plate is fixed in the accommodation cavity.

In some embodiments, a plurality of bypass holes are arranged on the first current collector, and the plurality of the bypass holes are arranged to be spaced apart around the circumference of the electrolyte injection hole in distribution.

In some embodiments, the battery cell further includes a second current collector, the second current collector is connected to an opposite end of the spiral-wound cell, and is arranged at a cathode of the spiral-wound cell.

In some embodiments, the battery cell further includes a housing and a terminal post. The spiral-wound cell is arranged to insert in the housing, the terminal post is fitted to the housing in an insulation manner through a first insulating member.

The terminal post includes a post part and a radial part connected to one end of the post part. The radial part has a diameter greater than a diameter of the post part, so that the terminal post is fixed on the housing. The radial part is connected to the second current collector.

In some embodiments, the battery cell is cylindrical.

In the present application, a battery is further provided, the battery includes the aforesaid battery cell.

The beneficial effects of the battery cell and the battery according to the present application are mainly described as follows:.

According to the battery cell of the present application, the first current collector is connected to one end of the spiral-wound cell and the electrolyte injection hole is arranged on the first current collector, electrolytes are injected through the electrolyte injection hole, and the cover plate is connected to the first current collector, and the first current collector is located between the spiral-wound cell and the cover plate. Thus, the electrolyte injection hole is sealed by the cover plate, so that the sealing of the electrolyte injection hole is quite ensured, the possibility of electrolyte leakage is reduced accordingly, and the safety of the battery cell is guaranteed.

In order to describe the embodiments of the present application more clearly, a brief introduction regarding the accompanying drawings that need to be used for describing the embodiments of the present application or the related art is given below.

Reference numerals involved in the accompanying figures are listed in detail below:
<NUM>-cover plate; <NUM>-spiral-wound cell; <NUM>-first current collector; <NUM>-electrolyte injection hole; <NUM>-first bursting line; <NUM>-second bursting line; <NUM>-accommodation cavity; <NUM>-strip-shaped groove; <NUM>-second current collector; <NUM>-insulating sleeve; <NUM>-housing; <NUM>-terminal post; <NUM>-post part; <NUM>-radical part; <NUM>-end cover; <NUM>-exposed part; <NUM>-axial part; <NUM>-radially convex part; <NUM>-first mounting hole; <NUM>-insulating sheet; <NUM>-second mounting hole; <NUM>-boss part; <NUM>-first insulating member; <NUM>-second insulating member; <NUM>-annular part; <NUM>-axially wrapped part; <NUM>-conductive sheet; <NUM>-insulating ring; <NUM>-notch.

In order to make the technical problem to be solved, the technical solutions and the advantages of the present application be clearer and more understandable, the present application will be further described in detail below with reference to accompanying figures and embodiments.

It needs to be noted that, when one component is described to be "fixed to" or "arranged on" another component, this component may be directly or indirectly arranged on another component. When it is described that one component "is connected with" another component, this component may be directly or indirectly connected to said another component.

In the description of the present application, it needs to be understood that, directions or location relationships indicated by terms such as "length", "width", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", and so on are the directions or location relationships shown in the accompanying figures, which are only intended to describe the present application conveniently and simplify the description, but not to indicate or imply that an indicated device or component must have specific locations or be constructed and manipulated according to specific locations; therefore, these terms shouldn't be considered as any limitation to the present application.

In addition, terms "the first" and "the second" are only used describing purposes, and should not be considered as indicating or implying any relative importance, or implicitly indicating the number of indicated technical features. As such, technical feature(s) restricted by "the first" or "the second" can explicitly or implicitly comprise one or more such technical feature(s). In the description of the present application, "a plurality of" has the meaning of at least two, unless "a plurality of" is provided with additional explicit and specific limitations.

In order to explain the technical solutions of the present application, the present application are described in detail with reference to the accompanying figures and the embodiments below.

Referring to <FIG>, a battery cell provided in the present application includes: a spiral-wound cell <NUM>, a first current collector <NUM> and a cover plate <NUM>. The first current collector <NUM> is connected to one end of the spiral-wound cell <NUM>, and the first current collector <NUM> is provided with an electrolyte injection hole <NUM>. The cover plate <NUM> is connected to the first current collector <NUM>, so that the cover plate <NUM> can seal the electrolyte injection hole <NUM>. The first current collector <NUM> is located between the spiral-wound cell <NUM> and the cover plate <NUM>, and then the electrolyte injection hole <NUM> is sealed using the cover plate <NUM>. During an assembling process of the battery cell, after the electrolytes are injected through the electrolyte injection hole <NUM> of the first current collector <NUM>, the cover plate <NUM> is used to seal the electrolyte injection hole <NUM> to realize sealing of the electrolyte injection hole <NUM>. In at least one embodiment of the present application, the first current collector <NUM> directly attached to the housing <NUM> is used as a rear support of the cover plate <NUM>, so that the cover plate <NUM> is able to withstand a greater impact force from the outside to the inside (i.e., withstand external impact, such as in a drop test) while having a smaller opening pressure from the inside to the outside when the cover plate <NUM> is not opened. Thus, when the battery cell is used in a cylindrical battery, a safety of the cylindrical battery is ensured.

In some embodiments, the method for sealing the electrolyte injection hole <NUM> by the cover plate <NUM> is that orifices of the electrolyte injection hole <NUM> are sealed by the cover plate <NUM>, or a closed space is formed between the cover plate <NUM> and the first current collector <NUM>. Since the first current collector <NUM> is further connected to the spiral-wound cell <NUM>, so that the electrolyte injection hole <NUM> is not exposed after the first current collector <NUM> is connected with the cover plate <NUM>, and the appearance of the battery cell is smooth and artistic, and risks of electrolyte leakage and oil seepage are avoided.

In one embodiment, the cover plate <NUM> and the first current collector <NUM> are connected by welding. Since the diameters of the cover plate <NUM> and the first current collector <NUM> are much greater than that of the conventional steel beads, welded joints having greater diameters can be formed when welding is used, so that a reduction of welding cracks and an improvement of the yield are facilitated. By welding the cover plate <NUM> with the first current collector <NUM>, a traditional condition of steel beads falling out under extreme temperature due to different material expansion rates is further avoided, and the tightness and the stability of the connection between the cover plate <NUM> and the first current collector <NUM> are ensured by welding.

In the present application, the first current collector <NUM> is connected to one end of the spiral-wound cell <NUM> by welding, and the electrolyte injection hole <NUM> is arranged on the first current collector <NUM>, electrolytes are injected through the electrolyte injection hole <NUM>, and the cover plate <NUM> is used to be connected to the first current collector <NUM>, so that the electrolyte injection hole <NUM> is blocked by the cover plate <NUM>, the sealing of the electrolyte injection hole <NUM> is quite ensured. Thus, a possibility of electrolyte leakage is reduced, and the safety of the battery cell is ensured.

Referring to <FIG>, one side of the cover plate <NUM> facing the first current collector <NUM> is provided with first bursting line(s) <NUM>, and the first bursting line(s) <NUM> is/are shaped as groove structure(s). The cover plate <NUM> has a function of sealing the injection hole <NUM> and an explosion-proof function. The first bursting line(s) <NUM> is/are arranged on the side of the cover plate <NUM> facing the first current collector, so that the first bursting line(s) <NUM> is avoided from being exposed. A condition of hiding dirt inside the first bursting line(s) <NUM> is avoided as compared to the conventional arrangement of exposed bursting lines, a cleanliness of coolant oil is ensured, and the appearance of the battery cell is smooth and artistic, and the risks of electrolyte leakage and oil seepage are avoided. The first bursting line(s) <NUM> is/are shaped as groove structure(s), thus, bursting is facilitated, and the safety of the battery cell is ensured.

Referring to <FIG>, in some embodiments, the cover plate <NUM> has a circular shape; the first current collector <NUM> has a circular shape, and the first bursting line(s) <NUM> is/are shaped as an arc line, or as a straight line, or as a polygonal line. When the first bursting line(s) <NUM> is/are shaped as arc, the arc is a circular arc and the circular arc is a major arc or a minor arc. The number of first bursting line(s) <NUM> is one or plural. When the number of first bursting lines <NUM> is plural and the plurality of first bursting lines <NUM> are arcuate, the plurality of first arcuate bursting lines <NUM> are evenly spaced apart in a circle in distribution, the center of the circle is the center of the cover plate <NUM>. When the number of the first bursting lines <NUM> is plural and the plurality of first bursting lines <NUM> are shaped as straight lines, the plurality of straight first bursting lines <NUM> are arranged in a radial pattern which takes the center of the cover plate <NUM> as the center.

Referring to <FIG>, in some embodiments, each first current collector <NUM> has an inner side and an outer side which are opposite to each other, the inner side of the first current collector <NUM> is connected to the spiral-wound cell <NUM>, and the cover plate <NUM> is connected to the outer side of the first current collector <NUM>. The inner side of the first current collector <NUM> faces the spiral-wound cell <NUM>, and is provided with second bursting lines <NUM> which are shaped as groove structures. By providing the second bursting lines <NUM>, the safety of the battery cell during use is further ensured. The second bursting lines <NUM> on the first current collector <NUM> are served as a pathway for electrolyte infiltration and gas discharge during production, the second bursting lines <NUM> are also served as prefabricated engraved lines for the rupture of the first current collector <NUM> in case of a thermal runaway. In case of the thermal runaway, the first bursting line(s) <NUM> on the cover plate <NUM> is/are fractured first, thereby realizing a gas pressure relief inside the battery cell. When the thermal runaway cannot be terminated after the first bursting line(s) <NUM> is/are fractured, the subsequently generated high pressure gas will tear the second bursting lines <NUM> on the first current collector <NUM>, in order that gases with high temperature thermal flows are ejected completely.

In one embodiment, the first current collector <NUM> is welded with the spiral-wound cell <NUM>. In particular, the first current collector <NUM> is connected to a tab of the spiral-wound cell <NUM>. The inner side of the cover plate <NUM> is connected to the outer side of the first current collector <NUM>, the first bursting line(s) <NUM> is/are located on the inner side of the cover plate <NUM>, and the outer side of the cover plate <NUM> is exposed. It is worth noting that the first current collector <NUM> and the spiral-wound cell <NUM> may be connected directly or indirectly.

In some embodiments, the number of the second bursting lines <NUM> is plural, and the plurality of second bursting lines <NUM> are spaced around the circumference of the electrolyte injection hole <NUM> in distribution. This arrangement facilitates ensuring the safety of the battery cell. Moreover, when bursting occurs, the bursting is prone to occur at the position of the electrolyte injection hole <NUM>.

In some embodiments, one end of each second bursting line <NUM> is extended to an edge of the electrolyte injection hole <NUM>, that is, one end of an opening of the groove structure in length direction is located on a hole wall of the electrolyte injection hole <NUM>. This arrangement further realizes the bursting occurring more likely at the position of the electrolyte injection hole in case of the occurrence of the bursting, and the safety of the battery cell is ensured during use.

In one embodiment, the second bursting lines <NUM> are shaped as straight lines, and the plurality of second bursting lines <NUM> are arranged in a radial pattern which takes the center of the hole of the electrolyte injection hole <NUM> as the center, that is, each second bursting line <NUM> has a length direction extended in the radial direction of the first current collector <NUM>.

In some embodiments, the first current collector <NUM> is arranged at an anode of the spiral-wound cell <NUM>, that is, the first current collector <NUM> is connected to an anode tab of the spiral-wound cell <NUM>, the electrolyte injection hole <NUM> is arranged at the middle of the first current collector <NUM>, the outer side of the first current collector <NUM> is provided with an accommodating cavity <NUM> recessed from one end of the spiral-wound cell <NUM> to the other end of the spiral-wound cell <NUM>, and the cover plate <NUM> is fixed in the accommodating cavity <NUM>. In at least one embodiment, the electrolyte injection hole <NUM> is arranged at the middle of the first current collector <NUM>, which facilitates simplification of mass production process and enables more accurate alignment with the electrolyte injection hole, and facilitates automatic electrolyte injection and the positioning of negative pressure formation procedure, etc., as compared to other methods of arrangement of the electrolyte injection hole in an offset position.

In one embodiment, the thickness of the cover plate <NUM> is equal to the depth of the accommodating cavity <NUM>, that is, after the cover plate <NUM> is fixed in the accommodating cavity <NUM>, the outer side of the cover plate <NUM> is flush with an outer surface of the first current collector <NUM>, so that one end surface of the anode of the battery cell is flat. The cover plate <NUM> is welded in the cavity of the current collector <NUM>, so that the battery cell has a smooth appearance. Due to the large diameter welding surface, a problem of stress concentration during welding is avoided, and the improvement of the yield of welding is facilitated. It should be noted that the accommodating cavity <NUM> can be formed by stamping.

In some embodiments, a bottom of the accommodating cavity <NUM> of the first current collector <NUM> has a plurality of strip-shaped recesses <NUM>, and the plurality of strip-shaped recesses <NUM> are radially distributed, and a length of each strip-shaped recess <NUM> extends along the radial direction of the first current collector <NUM>. The plurality of strip-shaped recesses <NUM> are provided at the bottom of the accommodating cavity when viewed from the outer side of the first current collector <NUM>, while the walls and bottoms of the plurality of strip-shaped recesses <NUM> are protruded from the inner side of the first current collector <NUM> when viewed from the inner side of the first current collector <NUM>, so that strip-shaped bosses are formed. Each second bursting line <NUM> is located between two adjacent strip-shaped bosses. It needs to be noted that the strip-shaped recesses <NUM> may be formed by stamping.

In some other embodiments, a plurality of bypass holes are further provided on the first current collector <NUM>, and the plurality of bypass holes are spaced around the circumference of the electrolyte injection holes <NUM> in distribution.

In some embodiments, the battery cell further includes a second current collector <NUM>, the second current collector <NUM> is connected to the opposite end of the spiral-wound cell <NUM>. The second current collector <NUM> is connected to a tab at the opposite end of the spiral-wound cell <NUM>. The second current collector <NUM> is arranged at a cathode of the spiral-wound cell <NUM>, in other words, the second current collector <NUM> is connected to a cathode tab of the spiral-wound cell <NUM>.

In some embodiments, the outer side of the second current collector <NUM> has a plurality of strip-shaped recesses <NUM>, the plurality of strip-shaped recesses <NUM> are radially distributed, and the length of each strip-shaped recess <NUM> is extended along the radial direction of the second current collector <NUM>. The plurality of strip-shaped recesses <NUM> are observed from the outer side of the second current collector <NUM>, while the walls and the bottoms of the plurality of strip-shaped recesses <NUM> are protruded from the inner side of the second current collector <NUM> when viewed from the inner side of the second current collector <NUM>, so that the strip-shaped bosses are formed. A circumferential edge of the second current collector <NUM> is further provided with a plurality of notches <NUM>, so that the second current collector <NUM> becomes a deformable and elastic structure that allows a small displacement of the spiral-wound cell <NUM> in an axial direction without damaging the welded areas between the second current collector <NUM> and the spiral-wound cell <NUM>, and the welded areas between the first current collector <NUM> and the spiral-wound cell <NUM>, respectively. It should be noted that in some other embodiments, the second current collector <NUM> can also be shaped as deformable and elastic structure in other forms.

In one embodiment, the first current collector <NUM> serves as the current collector at the anode of the spiral-wound cell <NUM> and the second current collector <NUM> serves as the current collector at the cathode of the spiral-wound cell <NUM>.

In some embodiments, the battery cell further includes an insulating sleeve <NUM>, the insulating sleeve <NUM> is cylindrically shaped, and the spiral-wound cell <NUM> is inserted in the insulating sleeve <NUM>. The battery cell further includes an insulating ring <NUM> sleeved on one end of the insulating sleeve <NUM>, and the insulating ring <NUM> is disposed at the opposite end of the spiral-wound cell <NUM>. The insulating ring <NUM> is further configured to enable the second current collector <NUM> to be fixed on the insulating sleeve <NUM>. The insulating ring <NUM> has a through-hole, a terminal post <NUM> of the battery cell is allowed to pass through the through-hole to be connected to the second current collector <NUM>.

Referring to <FIG>, in some embodiments, the battery cell further includes a housing <NUM> and a terminal post <NUM>, the spiral-wound cell <NUM> is inserted in the housing <NUM> and the terminal post <NUM> is insulated with the housing <NUM> through a first insulating member <NUM>. The terminal post <NUM> includes a post part <NUM> and a radial part <NUM> connected to one end of the post part <NUM>. The radial part <NUM> has a diameter greater than the diameter of the post part <NUM>, so that the terminal post <NUM> is fixed on the housing <NUM> due to this arrangement. The radial part <NUM> is connected to the second current collector <NUM>. The terminal post <NUM> is served as a cathode post. Compared with other methods of arranging the electrolyte injection hole on the terminal post, in at least one embodiment of the present application, the electrolyte injection hole <NUM> is arranged at the center of the anode of the terminal post <NUM> of the battery cell, so that the electrolyte injection hole <NUM> is not arranged at the end where the terminal post <NUM> is located, welding is facilitated, the structure of the battery cell is simplified, and an improvement of an overcurrent capacity of the terminal post <NUM> is improved. There is no need to add additional arrangement or visual identification procedure in battery module assembly. Additionally, the arrangement of non-exposed electrolyte injection hole <NUM> and reverse etching first blasting line(s) <NUM> and the second blasting lines <NUM> (i.e., arranged at the inner side) enables the whole terminal post <NUM> to have rotational and symmetrical design, the appearance of the cell is smooth and attractive, the risk of electrolyte leakage and oil seepage is avoided, and the problems that the battery module is difficult to be welded and cleaned, and the like are solved. This arrangement is very suitable for fully immersed oil cooling, and is compatible with conventional cooling methods (including side cooling, bottom cooling, and top cooling) filling glue.

It should be noted that, when the traditional cooling methods are used, the first bursting line(s) <NUM> and the second bursting lines <NUM> can be arranged on the outside to reduce a possibility of breakage in production and transportation equipment.

In one embodiment, the housing <NUM> is cylindrically shaped, and the insulating sleeve <NUM> is inserted in the housing <NUM>. One end of the housing <NUM> is opened, and the other end of the housing <NUM> is provided with an end cap <NUM>, the end cap <NUM> and the housing <NUM> are shaped as an integrated structure. The opposite end of the spiral-wound cell <NUM> and the other end of the housing <NUM> are arranged at the same side, and the terminal post <NUM> extends out of the end cap <NUM>. The radial part <NUM> is formed during a riveting process, the riveting of the terminal post <NUM> enables the diameter of the radial part <NUM> to be greater than the diameter of the post part <NUM> to prevent gas ejection from occurring in case of the thermal runaway.

In some embodiments, the terminal post <NUM> further includes an exposed part <NUM>, the exposed part <NUM> is circular in shape and the diameter of the exposed part <NUM> is greater than the diameter of the post part <NUM>. The material of the first insulating member <NUM> is an insulating rubber. The first insulating member <NUM> includes an axial part <NUM> and a radially convex part <NUM>. The radially convex part <NUM> is annular in shape. One end of the axial part <NUM> is connected to the radial convex part <NUM>, and the end face of the opposite end of the axial part <NUM> abuts against one side of the exposed part <NUM>. The first insulating member <NUM> is sleeved on the post part <NUM>.

In some embodiments, a center part of the end cap <NUM> of the housing <NUM> has a first mounting hole <NUM>, the first mounting hole <NUM> is a stepped through hole; a big aperture part of the first mounting hole <NUM> is away from the opposite end of the spiral-wound cell <NUM>, and a small aperture part of the first mounting hole <NUM> is adjacent to the opposite end of the spiral-wound cell <NUM>.

In some embodiments, the battery cell further includes an insulating sheet <NUM>, the insulating sheet <NUM> has a second mounting hole <NUM>, the second mounting hole <NUM> is a stepped through-hole; a big aperture part of the second mounting hole <NUM> is away from the opposite end of the spiral-wound cell <NUM>, while a small aperture part of the second mounting hole <NUM> is adjacent to the opposite end of the spiral-wound cell <NUM>. The stepped first mounting hole <NUM> and the second mounting hole <NUM> enable the thickness of the exposed part <NUM> of the terminal post <NUM> to be increased without increasing the total exposed height of the terminal post <NUM>, thereby supporting a welding of a connection piece having large overcurrent during a battery production process.

In some embodiments, an inner surface of the end cap <NUM> of the housing <NUM> is provided with a boss part <NUM>, and the boss part <NUM> is accommodated in the big aperture part of the second mounting hole <NUM>, so that the second mounting hole <NUM> of the insulating sheet <NUM> is coaxial with the first mounting hole <NUM> of the end cap <NUM>, and the positioning of the insulating sheet <NUM> on the inner surface of the end cap <NUM> of the housing <NUM> in the radial direction is realized. The radially convex part <NUM> is located at the small aperture part of the second mounting hole <NUM>. The axial part <NUM> of the first insulating member <NUM> is arranged to pass through the small aperture part of the first mounting hole <NUM>. The first insulating member <NUM> realized insulated isolation between the post part <NUM> of the terminal post <NUM> and the end cap <NUM>.

In one embodiment, the material of the insulating sheet <NUM> is Polyfluoroalkoxy (PFA).

In some embodiments, the battery cell further includes a second insulating member <NUM>, the second insulating member <NUM> is snapped onto the terminal post <NUM>. The second insulating member <NUM> is further snapped onto the axial part <NUM> of the first insulating member <NUM>. The material of the second insulating member <NUM> is PFA.

In some embodiments, the second insulating member <NUM> includes an annular part <NUM> and an axially wrapped part <NUM>, and the axially wrapped part125 is connected to one side surface of the annular part <NUM>. The axially wrapped part <NUM> is configured to wrap the circumference of the exposed part <NUM> of the terminal post <NUM>, and the annular part <NUM> is located between the inner side of the exposed part <NUM> and the bottom of the aperture of the big aperture part of the first mounting hole <NUM>, so that the insulated isolation between the exposed part <NUM> of the terminal post <NUM> and the outer surface of the end cap <NUM> of the housing <NUM> is realized through the second insulating member <NUM>.

In some embodiments, the battery cell further includes a conductive sheet <NUM> which is sleeved on the columnar portion <NUM> of the terminal post <NUM>, one side of the conductive sheet <NUM> abuts against the insulating sheet <NUM> and a radially convex part <NUM>, respectively. Thus, the insulated isolation between the conductive sheet <NUM> and the end cap <NUM> of the housing <NUM> is realized through the insulating sheet <NUM> and the first insulating member <NUM>. The conductive sheet <NUM> is disposed between the insulating sheet <NUM> and the radial part <NUM>. The insulating sheet <NUM> is disposed between the conductive sheet <NUM> and the end cap <NUM>.

In some embodiments, the first current collector <NUM> is further connected to the housing <NUM>, the first current collector <NUM> is recessed in the housing <NUM>. In one embodiment, a periphery of the first current collector <NUM> and the housing <NUM> are connected by welding.

In some embodiments, the first current collector <NUM> is made of aluminum material and the second current collector <NUM> is made of copper material. The terminal post <NUM> is made of copper. The conductive sheet <NUM> is made of copper material.

It should be noted that the material of the first current collector <NUM> is not merely limited to aluminum, the first current collector <NUM> can also be made using other materials, while the material of the second current collector <NUM>, the material of the terminal post <NUM> and the material of the conductive sheet are not only limited to copper, other materials can also be used according to the actual situation. In the production process, two ends of the spiral-wound cell <NUM> are welded with the first current collector <NUM> and the second current collector <NUM>, respectively. The spiral-wound cell <NUM> is sleeved on the insulating sleeve <NUM> and is inserted into the housing <NUM>. A welding needle inserts into the fluid injection hole <NUM> of the first current collector and makes the second current collector to be welded with the rear of the terminal post <NUM> through a center shaft hole of the spiral-wound cell <NUM>. Then, the first current collector <NUM> and an opening of the housing110 are pressed together and are welded using a periphery welding sealing process, the foil material of the cathode is naturally compressed. A part of the vacant foil material of the anode can be precompressed after the first current collector <NUM> is welded, electrolytes are injected through the electrolyte injection hole <NUM> of the first current collector <NUM>. Negative pressure is further pumped out from this hole through the negative pressure formation, so that produced gas is pumped out during battery cell formation. Then, after the cover plate <NUM> is placed in the accommodating cavity <NUM>, an end surface welding is used to seal the gap between the cover plate <NUM> and the first current collector <NUM>.

In some embodiments, the battery cell is a cylindrical battery cell. In one embodiment, the battery cell is a power battery cell.

In some embodiments, the battery cell has a diameter ranging from <NUM> to <NUM>, and has a height ranging from <NUM> to <NUM>.

Claim 1:
A battery cell, which comprises:
a spiral-wound cell (<NUM>);
a first current collector (<NUM>), the first current collector (<NUM>) is connected to one end of the spiral-wound cell (<NUM>), and the first current collector (<NUM>) is provided with an electrolyte injection hole (<NUM>); and
a cover plate (<NUM>), the cover plate (<NUM>) is connected to the first current collector (<NUM>), and the first current collector (<NUM>) is located between the spiral-wound cell (<NUM>) and the cover plate (<NUM>), in order that the electrolyte injection hole (<NUM>) is sealed by the cover plate (<NUM>);
characterized in that, one side of the cover plate (<NUM>) facing the first current collector (<NUM>) is provided with first bursting line(s) (<NUM>) which is/are shaped as groove structure(s).