CN220138648U

CN220138648U - Single battery

Info

Publication number: CN220138648U
Application number: CN202321652207.8U
Authority: CN
Inventors: 林秀德; 张猛; 杨伟; 陈辉
Original assignee: Xinwangda Power Technology Co ltd
Current assignee: Xinwangda Power Technology Co ltd
Priority date: 2023-06-27
Filing date: 2023-06-27
Publication date: 2023-12-05
Anticipated expiration: 2033-06-27

Abstract

The embodiment of the application discloses a single battery, which comprises a shell, a top cover assembly, a pole and an electric core. The top cover component is provided with a through assembly hole; the post includes post main part and first spacing portion, and the assembly hole is worn to locate by the post main part, and the periphery of post main part has first mating surface, and first mating surface inclines to set up relative first direction, and first mating surface and the pore wall sealing connection of assembly hole, first spacing position are located one side of top cap subassembly in first direction, and first spacing portion and post main part structure as an organic whole, first spacing portion and first mating surface cooperation centre gripping top cap subassembly. Compared with the prior art, the limit effect of the pole in the first direction is enhanced. Under the condition of guaranteeing the limiting effect, the size of the pole in the first direction can be reduced by arranging the first matching surface, so that the space utilization rate of the single battery is improved, and the energy density of the single battery is improved.

Description

Single battery

Technical Field

The application relates to the technical field of batteries, in particular to a single battery.

Background

The top cap of single battery includes the top cap piece and utmost point post.

Currently, the pole includes a main body portion and two limiting portions. The main body portion extends in the height direction of the single battery and has a columnar shape. The main body part is arranged in the mounting hole of the top cover plate in a penetrating way. The two limiting parts are respectively arranged at two ends of the main body part and extend outwards in the radial direction of the main body part. The two limiting parts are respectively abutted with the inner side and the outer side of the top cover sheet in the height direction, so that the main body part is fixed.

The dimension of the pole in the height direction influences the space utilization rate of the single battery in the height direction. In order to improve the space utilization of the single battery in the height direction, the dimension of the limit portion in the height direction needs to be reduced (the limit portion is thinned), but the strength of the pole (limit portion) in the height direction is also reduced, so that the limit effect of the pole in the height direction is weakened.

Disclosure of Invention

The embodiment of the utility model provides a single battery, which enhances the limit effect of a pole in the height direction.

In order to solve the technical problems, the embodiment of the utility model discloses the following technical scheme: in order to solve the technical problems, the embodiment of the utility model discloses the following technical scheme:

in one aspect, a battery cell is provided, the battery cell having a first direction, the battery cell including a housing, a cap assembly, a post, and a battery cell.

The top cover assembly is in butt joint with the shell along a first direction to form a containing cavity, and is provided with a penetrating assembly hole; the pole comprises a pole main body and a first limiting part, the pole main body is arranged in the assembly hole in a penetrating manner, a first matching surface is arranged on the periphery of the pole main body in an inclined manner relative to the first direction, the first matching surface is in sealing connection with the hole wall of the assembly hole, the first limiting part is positioned on one side of the top cover assembly in the first direction, the first limiting part and the pole main body are of an integrated structure, and the first limiting part and the first matching surface are matched to clamp the top cover assembly;

The battery cell is accommodated in the accommodating cavity and is electrically connected with the pole main body.

In addition to or in lieu of one or more of the features disclosed above, the normal positive direction of the first mating surface includes an acute angle with the first direction; the first limiting part is positioned at one side of the top cover component, which is opposite to the battery cell.

In addition to or in lieu of one or more of the features disclosed above, the post body has a first end face that faces the cell, the first mating face and the first end face abutting one another.

In addition to or in lieu of one or more of the features disclosed above, the cap assembly includes a cover sheet and a seal. The top cover sheet has an assembly hole; the sealing piece is clamped between the first matching surface and the hole wall of the assembly hole to form sealing; wherein the minimum distance H1 between the cover sheet and the first end surface in the first direction satisfies: h1 is more than or equal to 0mm and less than or equal to 2mm.

In addition to or in lieu of one or more of the features disclosed above, the post includes a second stop portion disposed at an end of the post body facing the cell, the first stop portion respectively engaging the second stop portion and the first mating surface to retain the cap assembly.

In addition to or in lieu of one or more of the features disclosed above, the cap assembly includes a cover sheet and a seal. The top cover sheet has an assembly hole; the sealing piece is clamped between the first matching surface and the hole wall of the assembly hole to form sealing; the minimum distance H2 between the end face of the second limiting part facing the battery cell and the top cover sheet in the first direction meets the following conditions: 0mm < H2<3mm.

In addition to or in lieu of one or more of the features disclosed above, the first stop has a stop surface facing the cell, the stop surface and the first mating surface abutting one another.

In addition to or in lieu of one or more of the features disclosed above, the wall of the mounting hole has a second mating surface disposed obliquely to the first direction, the second mating surface being disposed opposite and in sealing engagement with the first mating surface.

In addition to or in lieu of one or more of the features disclosed above, the cell has a cell body and a tab, the cell body being electrically connected to the tab; the electrode post main body is also provided with a first surface facing the battery core main body, the electrode lug extends along a first direction, the electrode lug is provided with a second end face facing away from the battery core main body, and the second end face is electrically connected with the first surface.

In addition to or in lieu of one or more of the features disclosed above, the post body also has a first recess, the first recess being notched toward the cell body, the first surface being located at a bottom of the first recess.

In addition to or in lieu of one or more of the features disclosed above, the cap assembly includes a cover sheet and a seal. The top cover sheet has an assembly hole; the sealing piece is clamped between the first matching surface and the hole wall of the assembly hole to form sealing; wherein the minimum distance H3 between the cover sheet and the first surface in the first direction satisfies: 0mm < H3<2mm, and the length H4 of the tab in the first direction satisfies the following conditions: h3< H4<6mm.

In addition to or in lieu of one or more of the features disclosed above, the post body also has a second recess with a notch facing away from the cell body, the first surface being disposed opposite a bottom of the second recess.

In addition to or in lieu of one or more of the features disclosed above, the number of tabs is multiple, with multiple tabs being stacked and adjacent tabs being in contact with one another.

In addition to or in lieu of one or more of the features disclosed above, the cell has a cell body and a tab, the cell body is electrically connected to the tab, and the tab is electrically connected to the post body.

The header assembly includes a top cover sheet, a rupture disc, and an insulator. The top cover plate is provided with an assembly hole and a pressure relief hole, and is also provided with a second surface adjacent to the pressure relief hole, and the second surface faces the battery cell main body; the explosion-proof piece is arranged in the pressure release hole and is provided with a third surface, the third surface faces the battery cell main body, and the third surface is far away from the battery cell main body relative to the second surface; the insulating piece is arranged on one side of the top cover sheet facing the battery cell main body, and the insulating piece and the third surface are mutually spaced in the first direction to form a pressure relief area.

In addition to or in lieu of one or more of the features disclosed above, the battery cell has a battery cell body and a tab, the battery cell body being electrically connected to the tab, the tab being electrically connected to the post body;

The header assembly includes a top cover sheet, a rupture disc, and an insulator. The top cover plate is provided with an assembly hole and a pressure relief hole, and is also provided with a second surface adjacent to the pressure relief hole, and the second surface faces the battery cell main body; the explosion-proof piece is arranged in the pressure release hole and is provided with a third surface, the third surface faces the battery cell main body, and the third surface is flush with the second surface or is close to the battery cell main body relative to the second surface; the insulating piece is arranged on one side of the top cover sheet facing the battery cell main body, and the insulating piece and the third surface are mutually spaced in the first direction to form a pressure relief area; the battery cell main body is provided with a third groove, and the notch of the third groove faces the top cover plate and is arranged opposite to the pressure release area.

In addition to one or more features disclosed above, or as an alternative, the length H5 of the pressure relief area in the first direction satisfies: 1mm < H5<5mm.

In addition to or in lieu of one or more of the features disclosed above, the cell has a second direction perpendicular to the first direction, the assembly hole and the pressure relief hole being spaced apart from each other along the second direction; wherein, the groove depth H6 of the third groove in the first direction satisfies: 1mm < H6<10mm, the length H7 of the third groove in the second direction satisfying: 10mm < H7<40mm.

One of the above technical solutions has the following advantages or beneficial effects:

the first matching surface is obliquely arranged relative to the first direction (height direction) and is in sealing connection with the hole wall of the assembly hole. The first mating surface is capable of functioning as a stop in a first direction. Compared with the prior art, the limit effect of the pole in the first direction is enhanced by the embodiment of the application. Under the condition of guaranteeing the limiting effect, the size of the pole in the first direction can be reduced by arranging the first matching surface, so that the space utilization rate of the single battery in the first direction is improved, and the energy density of the single battery is further improved.

In addition, the first limiting part and the pole main body are of an integrated structure, and compared with the first limiting part and the pole main body which are of a split structure, the strength of the pole is improved, and therefore the limiting effect in the first direction is enhanced.

Drawings

The technical solution and other advantageous effects of the present application will be made apparent by the following detailed description of the specific embodiments of the present application with reference to the accompanying drawings.

Fig. 1 is a three-dimensional exploded view of a battery cell according to an embodiment of the present application;

fig. 2 is a cross-sectional view of the unit cell shown in fig. 1;

FIG. 3 is a schematic cross-sectional view illustrating the connection between a tab and a post in the unit cell shown in FIG. 1;

FIG. 4 is a schematic view of the assembly of the top cap assembly and pole in an assembled scenario;

FIG. 5 is a schematic view of a process of assembling the cap assembly and pole in another assembly scenario;

FIG. 6 is a schematic cross-sectional view illustrating the connection between a tab and a post in a single battery according to another embodiment of the present application;

FIG. 7 is a schematic cross-sectional view illustrating the connection between a tab and a post in a single cell according to another embodiment of the present application;

fig. 8 is a schematic cross-sectional view of an explosion-proof structure of a single cell according to still another embodiment of the present application;

fig. 9 is a schematic cross-sectional view of an explosion-proof structure of a unit cell according to still another embodiment of the present application.

Reference numerals illustrate, 10-housing; a 20-top cap assembly; 201-a mounting hole; 203-a second mating surface; 205-through holes; 207-seals; 209-a pressure relief vent; 211-a top cover sheet; 213-a first insulating member; 215-a second insulator; 217-rupture disc; 219-a second surface; 221-a third surface; 223-vent holes; 30-a receiving cavity; 40-pole; 401-a first mating surface; 403-a first surface; 404—a first end face; 405-pole body; 407-first limit part; 409-a second limit part; 411-first groove; 415-a second groove; 417-a first stop surface; 419-a second stop surface; 50-cell; 501-a cell body; 503-tab; 505-third groove; 507-a second end face; l1-axis; d1—a first direction; d2—second direction.

Detailed Description

In order to make the objects, technical solutions and advantageous effects of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and detailed description. It should be understood that the detailed description is intended to illustrate the application, and not to limit the application.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more of the described features. In the description of the present application, the meaning of "plurality" means two or more, unless specifically defined otherwise.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; the connection may be mechanical connection, direct connection or indirect connection through an intermediate medium, and may be internal connection of two elements or interaction relationship of two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present application, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is less level than the second feature.

The single battery of the present application may be a lithium ion secondary battery, a lithium sulfur battery, a sodium lithium ion battery, or the like. The unit cell may be a solid state battery or a semi-solid state battery. The present application is not limited thereto.

The plurality of single batteries can be combined to form the battery module, so that energy can be provided for equipment such as vehicles, ships, small-sized airplanes and the like.

In the following embodiments, the unit cells are prismatic cells, and for convenience of description, the following definitions are provided: the single battery has a first direction D1, a second direction D2 and a third direction D3 which are perpendicular to each other. The first direction D1 is a height direction, the second direction D2 is a thickness direction, and the third direction D3 is a length direction.

Please refer to fig. 1 to 3. Fig. 1 is a three-dimensional exploded view of a battery cell according to an embodiment of the present application. Fig. 2 is a cross-sectional view of the unit cell shown in fig. 1. Fig. 3 is a schematic cross-sectional structure of the connection between the tab 503 and the post 40 in the unit cell shown in fig. 1.

The battery cell includes a housing 10, a cap assembly 20, a post 40, and a battery cell 50.

The housing 10 is a hollow structure having an opening. The material of the housing 10 may be an aluminum alloy. The housing 10 has a substantially rectangular parallelepiped shape.

The top cover assembly 20 is abutted with the housing 10 along the first direction D1 to form the accommodating chamber 30. Specifically, the top cap assembly 20 covers the opening of the case 10 and closes the opening.

The cap assembly 20 has a fitting hole 201 therethrough. The fitting hole 201 is used for mounting the pole 40.

The pole 40 is made of conductive material. The pole 40 is inserted into the assembly hole 201 of the cap assembly 20 and is connected with the cap assembly 20 in a sealing manner. The pole 40 is located in the accommodating cavity 30 at one end (bottom end) of the first direction D1 and is electrically connected to the battery cell 50 (tab 503), and the other end (top end) of the pole 40 is located outside the accommodating cavity 30 in the first direction D1 for outputting current. In the illustrated embodiment, the number of poles 40 is two, one pole 40 being a positive electrode and the other pole 40 being a negative electrode.

The connection structure of the post 40 and the cap assembly 20 is specifically as follows:

the cap assembly 20 includes a cap plate 211, a first insulating member 213, a second insulating member 215, and a sealing member 207.

The top sheet 211 may be made of a metal material. The cover 211 covers the opening of the case 10 and is welded to the case 10. The cover sheet 211 encloses the housing 10 to form the accommodating chamber 30. The fitting hole 201 is formed in the top cover 211.

The first insulating member 213 is disposed on the side of the top cover 211 facing the battery cell 50, and covers the surface of the top cover 211 facing the battery cell 50. The first insulating member 213 may be made of plastic material. The first insulating member 213 is configured to abut against the battery cell 50 in the first direction D1, so as to avoid the battery cell 50 from contacting the top cover 211, thereby avoiding a short circuit of the battery cell 50. The first insulating member 213 is provided with a through hole 205 at a position corresponding to the fitting hole 201. The through hole 205 penetrates the first insulator 213 in the first direction D1. The pole 40 is respectively inserted into the assembly hole 201 and the through hole 205, and presses the first insulating member 213 against the top cover 211 along the first direction D1, thereby fixing the first insulating member 213 to the top cover 211.

The sealing member 207 is sleeved outside the pole 40 and is clamped between the pole 40 and the wall of the assembly hole 201. The seal 207 provides a sealed connection between the post 40 and the cap piece 211. Specifically, the sealing member 207 may be made of rubber material.

The second insulating member 215 is located on the side of the top cover 211 facing away from the battery core 50, and is disposed around the pole 40, and fixedly connects the pole 40 and the top cover 211. The second insulator 215 may be molded between the top cover sheet 211 and the post 40 by injection molding.

The battery cell 50 is accommodated in the accommodating cavity 30.

The cell 50 includes a cell body 501 and tabs 503. The cell body 501 includes a positive electrode sheet (not visible in the figure), a separator (not visible in the figure), and a negative electrode sheet (not visible in the figure). In some embodiments, the positive, separator, and negative electrode sheets may be formed into the wound cell body 501 using a winding process. In other embodiments, the positive electrode sheet, the separator, the negative electrode sheet, and the separator may be stacked in order to form the stacked-type cell body 501. In other embodiments, the positive, separator, and negative electrode sheets may also be formed into the cell body 501 in a combination of a winding process and a lamination process. The cell body 501 is electrically connected to the tab 503. Specifically, tab 503 is connected to a pole piece (positive pole piece or negative pole piece). The tab 503 and the pole piece are in an integral structure or a split structure. In the embodiment in which the tab 503 and the pole piece are integrally formed, the portion of the positive electrode not coated with the polar material extends outward to form the tab 503. In the embodiment in which the tab 503 and the pole piece are in a split structure, the tab 503 is welded to the pole piece.

The limit structure between the pole 40 and the cap assembly 20 is specifically described below.

The post 40 has an axis L1. The axis L1 is parallel to the first direction D1.

The pole 40 includes a pole body 405, a first limit portion 407, and a second limit portion 409.

The post body 405 sequentially penetrates through the through hole 205 and the fitting hole 201.

The outer periphery of the post body 405 has a first mating surface 401. Specifically, the first mating surface 401 surrounds the pole body 405 around the axis L1.

The first mating surface 401 is disposed obliquely with respect to the first direction D1. Specifically, the angle α between the normal positive direction F of the first mating surface 401 and the first direction D1 is an acute angle.

The normal plus direction F is a direction perpendicular to the first mating surface 401 and from inside to outside. In this embodiment, since the first mating surface 401 is a curved surface, the normal positive direction F of the first mating surface 401 in each region is different, but the angle α between the normal positive direction F of the first mating surface 401 in each region and the first direction D1 is an acute angle.

The included angle α between the normal positive direction F and the first direction D1 is an acute angle, that is, the first mating surface 401 is located on the side of the pole body 405 facing away from the battery core 50; the included angle alpha between the normal positive direction F and the first direction D1 is a right angle, namely the first matching surface 401 is parallel to the first direction D1; the angle α between the normal positive direction F and the first direction D1 is an obtuse angle, that is, the first mating surface 401 is located on the side of the post body 405 facing the battery core 50.

The first mating surface 401 is in sealing connection with the wall of the assembly hole 201. Specifically, the sealing member 207 is accommodated in the assembly hole 201 and sleeved outside the pole body 405. The seal 207 is elastically deformed by the compression of the post body 405, filling between the first mating face 401 and the wall of the fitting hole 201 to form a seal.

The first mating surface 401 abuts the cap assembly 20 in the first direction D1. The first mating surface 401 can limit the degree of freedom of the post body 405 in the first direction D1.

The first limiting portion 407 is located on a side of the cap assembly 20 facing away from the battery cell 50. The first stopper 407 is integrally formed with the post body 405. The first limiting portion 407 has a first limiting surface 417 facing the battery cell 50. To reduce the size of the first direction D1 of the pole 40, the first limit surface 417 and the first mating surface 401 abut each other.

The first limit surface 417 abuts against the cap assembly 20 (the second insulator 215) in the first direction D1. The first stop surface 417 can limit the degree of freedom of the post body 405 in a direction opposite the first direction D1.

The second limiting portion 409 is disposed at an end of the terminal body 405 facing the battery core 50. The second limiting portion 409 and the post body 405 are integrally formed. The first limiting portion 407 has a second limiting surface 419 facing away from the cell 50. To reduce the size of the first direction D1 of the pole 40, the second limiting surface 419 and the first mating surface 401 abut each other.

The second stopper surface 419 abuts the cap assembly 20 (the first insulator 213) in the first direction D1. The second limiting surface 419 can limit the degree of freedom of the post 40 in the first direction D1. The tab 503 is electrically connected to the second limiting portion 409.

Thus, the first limiting portion 407 cooperates with the second limiting portion 409 and the first mating surface 401 to clamp the cap assembly 20, so that the pole 40 is fixed to the cap assembly 20.

In the related art, the pole 40 is limited in the first direction D1 only by the first limit portion 407 and the second limit portion 409. In this embodiment, the pole body 405 can also function as a stopper in the first direction D1, in addition to the first stopper 407 and the second stopper 409. Compared to the prior art, the limit effect of the pole 40 in the first direction D1 is enhanced.

In this embodiment, the first mating surface 401 can limit the degree of freedom of the pole 40 in the first direction D1. Under the condition of ensuring the limit effect of the pole 40 in the first direction D1, compared with the prior art, the size of the second limit portion 409 in the first direction D1 can be properly reduced to reduce the size of the pole 40 in the first direction D1, thereby improving the space utilization rate of the inside of the single battery in the first direction D1.

The smaller the dimension of the pole 40 in the first direction D1, the weaker the structural strength of the pole 40. The following test was conducted to determine the preferred size of the post 40, taking into consideration the improvement of the space utilization of the inside of the unit cell in the first direction D1, on the basis of ensuring the structural strength of the post 40.

Space utilization test of the interior of the single cell in the first direction D1:

1) Measuring the minimum distance H2 between the end face of the pole 40 facing the battery cell 50 and the top cover piece 211 in the first direction D1 by means of a vernier caliper and the like, and measuring for a plurality of times and taking an average value;

2) Measuring the minimum distance L between the top cover 211 and the bottom surface of the shell 10 in the first direction D1 by means of a vernier caliper and the like, and taking an average value by a plurality of times;

3) Space utilization = H2/L.

Structural strength test of the post 40:

1) Providing a pole 40;

2) When the terminal 40 is pressed and deformed along the axial direction of the terminal 40 by a drawing machine, the terminal 40 is pressed and deformed toward the end face of the battery cell 50, a tension value is recorded, the tension value is compared with a predetermined value, the predetermined value is marked as OK, and the predetermined value is marked as NG.

The test results were obtained as follows:

	H2(mm)	space utilization	Structural strength of pole
				Example 1	0.5	99.5％	OK
Example 2	1.0	99％	OK
				Example 3	1.5	98.5％	OK
Example 4	2	98％	OK
				Example 5	2.5	97.5％	OK
Example 6	2.9	97.1％	OK
				Example 7	3.0	97％	OK
Example 8	3.5	96.5％	OK
				Example 9	4.0	96％	OK

As can be seen from the above results, the minimum distance H2 between the end surface of the second limiting portion 409 facing the battery cell 50 and the top cover sheet 211 in the first direction D1 satisfies: when 0mm < H2<3mm, the structural strength of the pole 40 can be guaranteed, the space utilization rate of the inside of the single battery in the first direction D1 is relatively high, and the design requirement is met.

In other embodiments, the angle α between the normal positive direction F of the first mating surface 401 and the first direction D1 may be an obtuse angle, and accordingly, the first mating surface 401 can limit the degree of freedom of the pole 40 in the reverse direction of the first direction D1. Under the condition of ensuring the limiting effect of the pole 40 in the first direction D1, compared with the prior art, the size of the first limiting portion 407 in the first direction D1 can be properly reduced to reduce the size of the pole 40 in the first direction D1, thereby improving the space utilization of the outside of the single battery in the first direction D1.

In addition, the first limiting portion 407 and the pole body 405 are integrally configured, and compared with the first limiting portion 407 and the pole body 405 being of a split structure, the strength of the pole 40 is improved, thereby enhancing the limiting effect in the first direction D1.

In order to better limit the post body 405 to the cap assembly 20 in the first direction D1, the bore wall of the mounting bore 201 has a second mating surface 203. Specifically, the second mating surface 203 surrounds the assembly hole 201 around the axis L1. The second mating surface 203 is disposed obliquely with respect to the first direction D1, and the second mating surface 203 is disposed opposite to and in sealing connection with the first mating surface 401. Specifically, the second mating surface 203 is disposed parallel to the first mating surface 401. This can increase the area where the pole body 405 and the cap assembly 20 come into contact in the first direction D1, thereby enhancing the stopper effect in the first direction D1.

In the related art, in order to facilitate welding the tab 503 and the post 40, the tab 503 needs to be folded, so that a folding space needs to be reserved. This results in some spatial redundancy between the cell body 501 and the cap assembly 20, resulting in wasted space.

In order to increase the space utilization of the interior of the unit cell in the first direction D1, the present embodiment is further improved as follows.

The tab 503 is located on a side surface of the cell body 501 facing the cap assembly 20. The tab 503 extends toward the top cap assembly 20, i.e., in the first direction D1. The number of the tabs 503 is plural, the plural tabs 503 are stacked, and adjacent tabs 503 are in contact with each other.

The extending end of the tab 503 is electrically connected to the post 40. Specifically, the post body 405 also has a first surface 403 that faces the cell body 501. The tab 503 has a second end surface 507 facing away from the cell body 501. The second end surface 507 is electrically connected to the first surface 403, specifically, the second end surface 507 is welded to the first surface 403.

In this embodiment, the tab 503 is not required to be folded and is directly welded with the pole 40, so that the space utilization rate of the interior of the single battery in the height direction is improved, and the energy density of the single battery is improved.

Further, the post body 405 further has a second groove 415, the notch of the second groove 415 faces away from the cell body 501, and the first surface 403 is disposed opposite to the bottom of the second groove 415. By means of the arrangement, the electrode post main body 405 and the electrode lugs 503 can be welded and connected in a laser penetration welding mode commonly used in the industry, so that the welding difficulty is reduced, and the manufacturing cost of the single battery is reduced. In addition, the tab body 405 and the tab 503 can be welded together from the tab body 405 side (in the second groove 415), and damage to the tab 503 can be reduced as compared to welding together from the tab 503 side. For example, during welding, the weld puddle penetrates completely through the post body 405, but not the tab 503.

Please refer to fig. 4. Fig. 4 is a schematic view of a process of assembling the cap assembly 20 and the post 40 of the unit cell of fig. 1 in an assembled scenario.

In an assembly scenario, assembling the pole 40 to the cap assembly 20 includes the following process:

referring to section a of fig. 4, a top cap assembly 20 and a pole 40 are provided. The cap assembly 20 includes a cap piece 211, a first insulating member 213, and a sealing member 207 in an assembled state. The first stopper 407 of the post 40 is in the first state. In the first state, the first stopper 407 is connected to an end of the pole body 405 and extends in the axial direction (first direction D1) of the pole body 405.

Referring to part b of fig. 4, the pole 40 is inserted into the assembly hole 201.

Referring to part c of fig. 4, the cap assembly 20 and the pole 40 are put into a press molding die, and the pole 40 is press-molded such that the first stopper 407 is in the second state. In the second state, the first stopper 407 is connected to an end of the pole body 405 and extends in a radial direction of the pole body 405.

Referring to part d of fig. 4, the cap assembly 20 and the pole 40 are placed in an injection molding mold, and the second insulator 215 is injection molded.

Please refer to fig. 5. Fig. 5 is a schematic view of a process of assembling the cap assembly 20 and the post 40 of the unit cell of fig. 1 in another assembly scenario.

In another assembly scenario, assembling the pole 40 to the cap assembly 20 includes the following process:

referring to portion a of fig. 5, a top cap assembly 20 and a pole 40 are provided. The cap assembly 20 includes a cap piece 211, a first insulating member 213, a second insulating member 215, and a sealing member 207 in an assembled state. The first stopper 407 of the post 40 is in the first state. In the first state, the first stopper 407 is connected to an end of the pole body 405 and extends in the axial direction (first direction D1) of the pole body 405.

Referring to part b of fig. 5, the pole 40 is inserted into the assembly hole 201.

Referring to part c of fig. 5, the cap assembly 20 and the pole 40 are put into a press molding die, and the pole 40 is press-molded such that the first stopper 407 is in the second state. In the second state, the first stopper 407 is connected to an end of the pole body 405 and extends in a radial direction of the pole body 405.

The above-described method of assembling the pole 40 to the cap assembly 20 is only an example, and the present application is not limited thereto.

Please refer to fig. 6. Fig. 6 is a schematic cross-sectional structure of a connection between a tab 503 and a post 40 in a single cell according to another embodiment.

The battery cell embodiment shown in fig. 6 is different from the battery cell embodiment shown in fig. 1 in that the limit structure of the terminal 40 toward one end of the battery cell 50 is different. Correspondingly, the fixing manner of the first insulating member 213 is adaptively changed.

The difference between the embodiment of the single battery shown in fig. 6 and the embodiment of the single battery shown in fig. 1 is mainly described below, and the same points are referred to above, and are not repeated here.

The cap assembly 20 includes a cap plate 211, a first insulating member 213, a second insulating member 215, and a sealing member 207. Wherein the top cover piece 211 has a fitting hole 201. The first insulating member 213 is fixedly disposed on the side of the top cover 211 facing the battery cell 50. For example, the first insulator 213 is snap-fit or glued to the top cover piece 211.

The pole 40 includes a pole body 405 and a first stop 407.

The post body 405 is inserted into the mounting hole 201.

The outer periphery of the post body 405 has a first mating surface 401. The first mating surface 401 is disposed obliquely with respect to the first direction D1.

The first mating surface 401 is in sealing connection with the wall of the assembly hole 201. Specifically, the seal 207 is sandwiched between the first mating face 401 and the wall of the fitting hole 201 to form a seal.

The post body 405 has a first end face 404 facing the cell 50, the first mating face 401 and the first end face 404 abutting each other. That is, the side of the post body 405 facing the cell 50 is free of other components.

The first limit surface 417 abuts against the cap assembly 20 in the first direction D1. Specifically, the first limiting surface 417 abuts against the second insulating member 215 in the first direction D1. The first stop surface 417 can limit the degree of freedom of the post body 405 in a direction opposite the first direction D1.

Thereby, the first stopper 407 cooperates with the first mating surface 401 to clamp the cap assembly 20, so that the pole 40 is fixed to the cap assembly 20.

Compared with the single battery embodiment shown in fig. 1, the single battery embodiment shown in fig. 6 omits the second limiting portion 409, thereby further reducing the height of the pole 40 in the first direction D1, and further improving the space utilization of the interior of the single battery in the first direction D1.

The preferred dimensions of the post 40 are determined using the same test method as the embodiment shown in fig. 1, with the following test results:

	H1(mm)	space utilization	Structural strength of pole
				Example 1	0	100％	OK
Example 2	0.5	99.5％	OK
				Example 3	1.0	99％	OK
Example 4	1.5	98.5％	OK
				Example 5	1.9	98.1％	OK
Example 6	2.0	98％	OK
				Example 7	2.5	97.5％	OK
Example 8	3.0	97％	OK

From the above results, the minimum distance H1 between the top cover sheet 211 and the first end surface 404 in the first direction D1 satisfies: when H1 is more than or equal to 0mm and less than or equal to 2mm, the structural strength of the pole 40 can be ensured, the space utilization rate of the inside of the single battery in the first direction D1 is relatively high, and the design requirement is met.

Please refer to fig. 7. Fig. 7 is a schematic cross-sectional structure of a connection between a tab 503 and a post 40 in a single cell according to another embodiment.

The cell embodiment of fig. 7 differs from the cell embodiment of fig. 1 in that the structure of the post 40 at the junction with the tab 503 is different.

The difference between the embodiment of the single battery shown in fig. 7 and the embodiment of the single battery shown in fig. 1 is mainly described below, and the same points are referred to above, and are not repeated here.

The tab 503 is located on a side surface of the cell body 501 facing the cap assembly 20. The tab 503 extends toward the top cap assembly 20, i.e., in the first direction D1. The tab 503 has a second end surface 507 facing away from the cell body 501.

The post body 405 has a first recess 411. The notch of the first groove 411 faces the cell main body 501.

The post body 405 also has a first surface 403 that faces toward the cell body 501. The first surface 403 is located at the bottom of the first recess 411.

The post body 405 also has a second recess 415. The notch of the second recess 415 faces away from the cell body 501. The first surface 403 is disposed opposite the bottom of the second recess 415.

The second end surface 507 of the tab 503 is electrically connected to the first surface 403, specifically, the second end surface 507 is welded to the first surface 403.

In this embodiment, the extending end of the tab 503 is inserted into the first groove 411 and is electrically connected to the pole 40, so that the space occupied by the tab 503 in the first direction D1 is reduced, and the available space of the interior of the single battery in the first direction D1 is increased.

The greater the depth of the first recess 411, the greater the available space is increased, but at the same time, the longer the length of the tab 503, the greater the resistance of the tab 503, and the greater the probability of accidental breakage of the tab 503. For this, the following test is performed to determine the depth of the first recess 411 and the preferred value of the length of the tab 503.

Space increasing rate test of the interior of the single cell in the first direction D1:

1) Measuring the minimum distance H3 between the top cover 211 and the first surface 403 in the first direction D1 by a vernier caliper or other means, and taking an average value by a plurality of times;

3) Space increase rate=h3/L.

The test results were obtained as follows:

	H3(mm)	H4(mm)	space increasing rate
				Example 1	0	4	0
Example 2	0.5	4.5	0.5％
				Example 3	1.0	5	1％
Example 4	1.5	5.5	1.5％
				Example 5	1.9	5.9	1.9％
Example 6	2.0	6	2％
				Example 7	2.5	6.5	2.5％
Example 8	3.0	7	3％

From the above results, the minimum distance H3 between the top cover sheet 211 and the first surface 403 in the first direction D1 satisfies: 0mm < H3<2mm, and the length H4 of the tab 503 in the first direction D1 satisfies: when H3 is less than H4 is less than 6mm, the design requirement can be met.

Please refer to fig. 8. Fig. 8 is a schematic cross-sectional view of an explosion-proof structure of a battery cell according to still another embodiment.

The embodiment shown in fig. 8 is a further development on the basis of the embodiment shown in fig. 1, the embodiment shown in fig. 6 and the embodiment shown in fig. 7. The following focuses on the improvement of the embodiment of the single battery shown in fig. 8, and other parts are referred to above, and are not repeated here.

The cap assembly 20 includes a cap plate 211, a rupture disc 217, a first insulator 213, and a second insulator 215.

The top cover sheet 211 has a fitting hole 201 and a pressure release hole 209. The fitting hole 201 and the pressure release hole 209 are disposed at a distance from each other along the second direction D2. The pressure relief hole 209 penetrates the top cover sheet 211 in the first direction D1.

The top cover sheet 211 also has a second surface 219 that abuts the pressure relief aperture 209. The second surface 219 faces the cell body 501.

A rupture disc 217 is disposed in the pressure relief vent 209. The rupture disc 217 may be welded to close the pressure relief vent 209. Explosion-proof scores are arranged on the explosion-proof sheet 217. When the air pressure in the unit cell is greater than a predetermined value, the rupture disc 217 is ruptured, thereby opening the pressure relief hole 209.

The rupture disc 217 has a third surface 221. The third surface 221 faces the cell body 501. The third surface 221 is remote from the cell body 501 relative to the second surface 219.

The first insulator 213 is provided on the side of the top cover 211 facing the cell body 501. The first insulating member 213 is provided with a vent hole 223 at an opposite third surface 221. The first insulating member 213 and the third surface 221 are spaced apart from each other in the first direction D1 to form a pressure relief region.

When the single battery is out of control, gas enters the pressure relief area through the exhaust hole 223 and is exhausted to the outside through the pressure relief hole 209.

In the related art, the explosion-proof sheet 217 is disposed flush with the second surface 219, and accordingly, the first insulating member 213 needs to be recessed toward the side of the cell 50 to form a pressure release region. In the related art, the pressure release area occupies the space inside the unit cell in the first direction D1.

In this embodiment, the pressure relief area is generally recessed toward the top cover assembly 20 along the first direction D1, and the pressure relief area does not occupy the space of the interior of the unit cell in the first direction D1, thereby improving the space utilization of the interior of the unit cell in the first direction D1.

The greater the length H5 of the pressure relief area in the first direction D1, the greater the increased available space, but at the same time the weaker the structural strength of the top cover sheet 211. For this purpose, the following test is performed to determine the preferred value of the length H5.

1) Measuring the length H5 of the pressure release area in the first direction D1 by means of a vernier caliper and the like, measuring for a plurality of times and taking an average value;

3) Space increase rate=h5/L.

Structural strength test of the post 40:

1) Providing a top cover sheet 211;

2) A drawing machine is used to act on the top cover sheet 211, push the top cover sheet 211 along the thickness direction of the top cover sheet 211 until the top cover sheet 211 is deformed, record a tension value, compare the tension value with a predetermined value, and mark the tension value as OK when the tension value is greater than or equal to the predetermined value and as NG when the tension value is smaller than the predetermined value.

The test results were obtained as follows:

	H5(mm)	space increasing rate	Structural strength of top cover sheet
				Example 1	0.5	0.5％	OK
Example 2	1.0	1％	OK
				Example 3	1.5	1.5％	OK
Example 4	2.0	2％	OK
				Example 5	3.0	3％	OK
Example 6	4.0	4％	OK
				Example 7	5.0	5％	OK
Comparative example 1	6.0	6％	NG
				Comparative example 2	7.0	7％	NG
Comparative example 3	8.0	8％	NG

From the above results, the length H5 of the pressure release region in the first direction D1 satisfies: when 1mm < H5<5mm, the design requirements can be met.

Please refer to fig. 9. Fig. 9 is a schematic sectional view of an explosion-proof structure in a unit cell according to still another embodiment.

The embodiment shown in fig. 9 is a further development on the basis of the embodiment shown in fig. 1, the embodiment shown in fig. 6 and the embodiment shown in fig. 7. The following focuses on the improvement of the embodiment of the single battery shown in fig. 9, and other parts are referred to above, and are not repeated here.

The rupture disc 217 has a third surface 221. The third surface 221 faces the cell body 501. The third surface 221 is flush with the second surface 219 (as shown) or the third surface 221 is proximate the cell body 501 relative to the second surface 219.

The first insulator 213 is provided on the side of the top cover 211 facing the cell body 501. The first insulating member 213 is provided with a vent hole 223 at an opposite third surface 221. The first insulating member 213 and the third surface 221 are spaced apart from each other in the first direction D1 to form a pressure relief region. Specifically, the length H5 of the pressure release region in the first direction D1 satisfies: 1mm < H5<5mm.

The cell body 501 has a third groove 505, and a notch of the third groove 505 is disposed toward the top cover 211 and opposite to the pressure release area. Specifically, the groove depth H6 of the third groove 505 in the first direction D1 satisfies: 1mm < H6<10mm, the length H7 of the third groove 505 in the second direction D2 satisfies: 10mm < H7<40mm.

In this embodiment, the portion of the first insulating member 213 forming the pressure release region can be accommodated in the third groove 505, so that the available space of the interior of the unit cell in the first direction D1 is increased.

To determine the degassing effect of the unit cell at the time of thermal runaway, the following test was performed to determine a preferred value of the size of the third groove 505.

The exhaust testing method of the single battery comprises the following steps: and (3) obtaining the exhaust rate by carrying out fluid simulation on structures with different sizes, comparing the exhaust rate with a preset value, marking the exhaust rate as OK when the exhaust rate is greater than or equal to the preset value, and marking the exhaust rate as NG when the exhaust rate is less than the preset value.

The test results were obtained as follows:

	H6(mm)	H7(mm)	single battery exhaust
				Example 1	1.0	10.0	OK
Example 2	10.0	10.0	OK
				Example 3	1.0	20.0	OK
Example 4	10.0	20.0	OK
				Example 5	1.0	40.0	OK
Example 6	10.0	40.0	OK
				Comparative example 1	10.0	9.0	NG
Comparative example 2	0.9	40.0	NG

In summary, in the embodiment of the single battery of the present application, the post 40 has the first mating surface 401, and the first mating surface 401 is disposed obliquely with respect to the first direction D1 (the height direction) and is connected with the hole wall of the assembly hole 201 in a sealing manner. The first mating surface 401 can function as a stop in the first direction D1. Compared to the prior art, the limit effect of the pole 40 in the first direction D1 is enhanced.

Under the condition of ensuring the limiting effect, the size of the pole 40 in the first direction D1 can be reduced, so that the space utilization rate of the single battery is improved, and the energy density of the single battery is further improved.

The first limiting portion 407 and the pole body 405 are of an integral structure, and compared with the first limiting portion 407 and the pole body 405 being of a split structure, the strength of the pole 40 is improved, so that the limiting effect in the first direction D1 is enhanced.

The tab 503 is embedded into the pole 40, so that the space above the battery core main body 501 (towards one side of the top cover assembly 20) is saved, and the space utilization rate of the inside of the single battery is improved, and the energy density of the single battery is further improved.

The tab 503 is not required to be bent, and is directly welded and connected with the pole post 40 in a penetration welding mode, so that the redundancy of the tab 503 is reduced, the switching sheet is omitted, the space utilization rate of the inside of the single battery is improved, and the energy density of the single battery is further improved.

The tab 503 does not need to be bent, so that risks of tearing, breaking, interpolation, short circuit and the like of the tab 503 are avoided.

The above steps are presented merely to aid in understanding the method, structure, and core concept of the application. It will be apparent to those skilled in the art that various changes and modifications can be made to the present application without departing from the principles of the application, and such changes and modifications are intended to be included within the scope of the appended claims.

Claims

1. A single cell, wherein the single cell has a first direction, the single cell comprising:

a housing;

the top cover assembly is in butt joint with the shell along the first direction to form a containing cavity, and the top cover assembly is provided with a penetrating assembly hole;

the pole comprises a pole main body and a first limiting part, wherein the pole main body penetrates through the assembly hole, a first matching surface is arranged on the periphery of the pole main body and is inclined relative to the first direction, the first matching surface is in sealing connection with the hole wall of the assembly hole, the first limiting part is positioned on one side of the top cover assembly in the first direction, the first limiting part and the pole main body are of an integrated structure, and the first limiting part and the first matching surface are matched and clamp the top cover assembly;

2. The unit cell according to claim 1,

an included angle between the normal positive direction of the first matching surface and the first direction is an acute angle;

the first limiting part is positioned on one side of the top cover assembly, which is opposite to the battery cell.

3. The unit cell according to claim 2,

the post body has a first end face facing the battery cell, the first mating face and the first end face abutting each other.

4. The cell as defined in claim 3, wherein the cap assembly comprises:

a top cover sheet having the fitting hole; and

the sealing piece is clamped between the first matching surface and the hole wall of the assembly hole to form a seal;

wherein a minimum distance H1 between the top cover sheet and the first end face in the first direction satisfies: h1 is more than or equal to 0mm and less than or equal to 2mm.

5. The cell as defined in claim 2, wherein the post comprises:

the second limiting part is arranged at the end part of the pole body, facing the battery core, and the first limiting part is matched with the second limiting part and the first matching surface to clamp the top cover assembly.

6. The cell as defined in claim 5, wherein the cap assembly comprises:

a top cover sheet having the fitting hole; and

the minimum distance H2 between the end face of the second limiting part facing the battery cell and the top cover sheet in the first direction meets the following conditions: 0mm < H2<3mm.

7. The unit cell according to any one of claim 1 to 6,

the first limiting part is provided with a limiting surface facing the battery cell, and the limiting surface and the first matching surface are adjacent to each other.

8. The unit cell according to any one of claim 1 to 6,

the pore wall of the assembly pore is provided with a second matching surface, the second matching surface is obliquely arranged relative to the first direction, and the second matching surface is oppositely arranged with the first matching surface and is in sealing connection.

9. The unit cell according to any one of claim 1 to 6,

the battery cell is provided with a battery cell main body and a tab, and the battery cell main body is electrically connected with the tab; the electrode post main body is also provided with a first surface facing the battery cell main body, the electrode lug extends along the first direction, the electrode lug is provided with a second end face facing away from the battery cell main body, and the second end face is electrically connected with the first surface.

10. The unit cell according to claim 9,

the pole body is also provided with a first groove, the notch of the first groove faces the battery cell body, and the first surface is positioned at the bottom of the first groove.

11. The cell as defined in claim 10, wherein the cap assembly comprises:

a top cover sheet having the fitting hole; and

wherein a minimum distance H3 between the cover sheet and the first surface in the first direction satisfies: 0mm < H3<2mm, the length H4 of the tab in the first direction satisfying: h3< H4<6mm.

12. The unit cell according to claim 9,

the electrode post main body is also provided with a second groove, the notch of the second groove faces away from the battery cell main body, and the first surface and the bottom of the second groove are oppositely arranged.

13. The unit cell according to claim 9,

the number of the lugs is multiple, the lugs are stacked, and adjacent lugs are in contact with each other.

14. The unit cell according to claim 1,

the battery cell is provided with a battery cell main body and a pole lug, the battery cell main body is electrically connected with the pole lug, and the pole lug is electrically connected with the pole post main body;

the top cap assembly includes:

the top cover plate is provided with the assembly hole and the pressure relief hole, and also provided with a second surface adjacent to the pressure relief hole, and the second surface faces the battery cell main body; and

The explosion-proof piece is arranged in the pressure relief hole and is provided with a third surface, the third surface faces the battery cell main body, and the third surface is far away from the battery cell main body relative to the second surface; and

the insulating piece is arranged on one side of the top cover sheet facing the battery cell main body, and the insulating piece and the third surface are mutually spaced in the first direction to form a pressure relief area.

15. The unit cell according to claim 1,

the top cap assembly includes:

the explosion-proof piece is arranged in the pressure relief hole and is provided with a third surface, the third surface faces the battery cell main body, and the third surface is flush with the second surface or is close to the battery cell main body relative to the second surface; and

the insulating piece is arranged on one side, facing the battery cell main body, of the top cover piece, and the insulating piece and the third surface are mutually spaced in the first direction to form a pressure relief area;

The battery cell main body is provided with a third groove, and the notch of the third groove faces the top cover sheet and is opposite to the pressure relief area.

16. The unit cell according to claim 14 or 15,

the length H5 of the pressure release region in the first direction satisfies: 1mm < H5<5mm.

17. The unit cell according to claim 15,

the single battery is further provided with a second direction perpendicular to the first direction, and the assembly holes and the pressure relief holes are arranged at intervals along the second direction;

wherein the groove depth H6 of the third groove in the first direction satisfies: 1mm < H6<10mm, the length H7 of the third groove in the second direction satisfying: 10mm < H7<40mm.