CN219436086U - Secondary battery - Google Patents

Abstract

The utility model discloses a secondary battery, which comprises a shell, a shell cover, a battery core, a current collecting disc, a pole and a first insulating piece. One end of the shell is a closed end, and the other end is an open end. The cover closes the open end of the housing. The electric core is arranged in the shell, the first pole of the electric core faces the shell cover, the second pole of the electric core faces the closed end of the shell, and the second pole is electrically connected with the bottom of the shell. The current collecting disc is arranged in the shell, connected with the first pole of the battery cell and insulated from the shell cover and the shell. The post runs through the cap, and the post is located the outside one side of casing and includes the recess, and the bottom and the current collecting disk welding of recess link to each other. The first insulating piece is sleeved on the pole to separate the pole from the shell cover. The secondary battery has good electrical safety performance.

Description

Secondary battery

Technical Field

The utility model relates to the technical field of batteries, in particular to a secondary battery.

Background

The secondary battery is used as the power supply part of the electric automobile, and determines key indexes such as the endurance mileage, the cost, the service life, the safety, the maintainability and the like of the whole automobile.

Currently, a secondary battery includes a battery case and a battery cell, and electrode tabs are mounted at mounting holes of the battery case and electrically connected with tabs of the battery cell through current collecting plates, thereby outputting current generated by the battery cell to the battery case. In the existing manufacturing process of the secondary battery, the shell comprises a shell body and a shell cover, the pole is arranged in a mounting hole on the shell body and riveted with the shell body, then the pole and the current collecting disc are connected together through threads, and then the shell body, the shell cover and the current collecting disc are connected together.

In general, the packaging form of casing and cap is that roll groove later locates the sealing washer between casing and the cap and mound and seal earlier, and at roll groove and turn-ups in-process, current collecting plate and casing junction are because there is relative slip, and both easily break away from, lead to both to contact failure, electrical connection inefficacy on the one hand, influence electric core internal resistance and current-carrying capacity, on the other hand current collecting plate can produce the metal fillings that can drop after breaking away from with the casing, influence the electric safety of secondary cell. In summary, the secondary battery of the related art has poor electrical safety performance.

Disclosure of Invention

The utility model aims to provide a secondary battery, which improves the electrical safety performance of the secondary battery.

To solve the above technical problems, an embodiment of the present utility model provides a secondary battery including:

the shell is provided with a closed end at one end and an open end at the other end;

a cover closing the open end of the housing;

the battery cell is arranged in the shell, a first pole of the battery cell faces the shell cover, a second pole of the battery cell faces the closed end of the shell, and the second pole is electrically connected with the bottom of the shell;

the current collecting disc is arranged in the shell, connected with the first pole of the battery cell and insulated with the shell cover and the shell;

the pole penetrates through the shell cover, one side of the pole, which is positioned outside the shell, comprises a recess, and the bottom of the recess is connected with the current collecting disc in a welding way; and

the first insulating piece is sleeved on the pole to separate the pole from the shell cover.

Compared with the prior art, the current collecting disc has no connection relation with the shell and the shell cover, so when the shell and the shell cover are packaged, namely, the roll groove and the flanging are arranged in the process, the current collecting disc and the shell do not slide relatively, the current collecting disc is electrically connected with the pole by welding, the connection part of the current collecting disc and the pole is not separated, the poor contact and the electrical failure are avoided, and the internal resistance and the current carrying capacity of the battery core are not influenced. In addition, the falling metal scraps are not generated, and safety accidents are caused, so that the secondary battery has higher electrical safety performance.

In one embodiment, the housing is electrically connected to the housing cover.

In one embodiment, the thickness of the bottom of the recess is 0.1mm-2mm.

In one embodiment, the current collecting disc is at least partially protruded towards the direction of the pole to form a boss, and the bottom of the recess is welded with the boss.

In one embodiment, the current collecting plate further comprises a main body part, and the boss protrudes from the main body part to the bottom of the pole; and the boss separates the bottom of the pole from the body portion.

In one embodiment, a support member for supporting the cover is sandwiched between the collecting tray and the cover.

In an embodiment, the support is an insulating elastic support.

In one embodiment, the open end has a support deck for the housing cover.

In one embodiment, the housing comprises: a side wall surrounding a closed end thereof, the side of the side wall facing away from the closed end being the open end;

the part of the side wall close to the opening end protrudes into the shell to form a lug, and one side of the lug, which is away from the battery cell, is the supporting table top; or (b)

The side wall is close to the part of the open end and is provided with a mounting groove, the shell cover is operably embedded into the mounting groove, the mounting groove is provided with a groove bottom facing the open end, and the groove bottom is the supporting table surface.

In one embodiment, the housing is welded to the cover.

In one embodiment, the housing comprises: a side wall surrounding a closed end thereof, the side of the side wall facing away from the closed end being the open end; an embedded groove is formed in the outer wall of the shell cover, and the side wall is operably embedded in the embedded groove.

In one embodiment, the housing comprises: a side wall surrounding a closed end thereof, the side of the side wall facing away from the closed end being the open end; the side wall is higher than the part of the battery cell and is provided with an inner concave part facing the inner concave part of the shell, and the shell cover is arranged on the inner concave part.

In one embodiment, the wall of the inner recess directly sandwiches the insulation with the collector plate.

In an embodiment, the open end is bent towards the upper part of the shell cover to form a bending part, and the bending part is pressed on the top of the shell cover.

In one embodiment, the bending part is welded with the top of the shell cover.

Drawings

Fig. 1 is a schematic view of a structure of a secondary battery according to an embodiment of the present utility model;

FIG. 2 is an enlarged view of a portion of FIG. 1A;

FIG. 3 is an enlarged view of a portion of B in FIG. 1;

fig. 4 is a schematic structural view of a secondary battery according to another embodiment of the present utility model;

FIG. 5 is an enlarged view of a portion of C in FIG. 4;

FIG. 6 is an enlarged view of part of D in FIG. 4;

fig. 7 is a schematic structural view of a secondary battery according to still another embodiment of the present utility model;

FIG. 8 is an enlarged view of a portion of E in FIG. 7;

fig. 9 is a schematic structural view of a secondary battery according to another embodiment of the present utility model;

fig. 10 is a partial enlarged view of F in fig. 9;

fig. 11 is a schematic structural view of a secondary battery according to another embodiment of the present utility model;

fig. 12 is a partial enlarged view of G in fig. 11;

fig. 13 is a schematic view of a structure of a secondary battery according to another embodiment of the present utility model;

fig. 14 is a partial enlarged view of H in fig. 13.

Reference numerals:

1. a secondary battery; 10. a housing; 11. an open end; 12. supporting the table top; 13. a bump; 14. an inner recess; 15. a bending part; 16. a closed end; 17. a sidewall; 20. a cover; 21. an embedding groove; 30. a battery cell; 40. a collecting tray; 41. a boss; 42. a main body portion; 50. a pole; 51. a recess; 60. a first insulating member; 70. a support; 80. an isolation insulator; a. thickness of the bottom of the recess.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, embodiments of the present utility model will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art will understand that in various embodiments of the present utility model, numerous technical details have been set forth in order to provide a better understanding of the present application. However, the technical solutions claimed in the claims of the present application can be realized without these technical details and various changes and modifications based on the following embodiments.

Throughout the specification and claims, unless the context requires otherwise, the word "comprise" and variations such as "comprises" and "comprising" will be understood to be open-ended, meaning of inclusion, i.e. to be interpreted to mean "including, but not limited to.

The following detailed description of various embodiments of the present utility model will be provided in connection with the accompanying drawings to provide a clearer understanding of the objects, features and advantages of the present utility model. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the utility model, but rather are merely illustrative of the true spirit of the utility model.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the term "or" is generally employed in its sense including "and/or" unless the context clearly dictates otherwise.

In the following description, for the purposes of clarity of presentation of the structure and manner of operation of the present utility model, the description will be made with the aid of directional terms, but such terms as "forward," "rearward," "left," "right," "outward," "inner," "outward," "inward," "upper," "lower," etc. are to be construed as convenience, and are not to be limiting.

Embodiments of the present utility model are described below with reference to the accompanying drawings.

Implementation details of the present embodiment are specifically described below, and the following description is provided only for facilitating understanding, and is not necessary to implement the present embodiment.

As shown in fig. 1, an embodiment of the present utility model provides a secondary battery 1, the secondary battery 1 including a case 10, a case cover 20, a battery cell 30, a current collecting plate 40, a post 50, and a first insulating member 60. The housing 10 has a closed end 16 at one end and an open end 11 at the other end. The cover 20 closes the open end 11 of the housing 10. The battery cell 30 is disposed in the housing 10, with the positive electrode of the battery cell 30 facing the housing cover 20, the negative electrode of the battery cell 30 facing the bottom of the housing 10, i.e., the negative electrode of the battery cell 30 facing the closed end 16 of the housing 10, and the negative electrode being electrically connected to the bottom of the housing 10. The current collecting plate 40 is disposed in the housing 10 and connected to the positive electrode of the battery cell 30, the positive electrode of the battery cell 30 has a positive tab which can be welded to the current collecting plate 40, and the current collecting plate 40 is insulated from the housing cover 20 and the housing 10. Fig. 2 shows an enlarged view of a portion of the pole 50 of fig. 1, as shown in fig. 2, the pole 50 penetrates through the case cover 20, a side of the pole 50 located outside the case 10 includes a recess 51, and the bottom of the recess 51 is welded to the collecting tray 40. The first insulating member 60 is sleeved on the pole 50 to separate the pole 50 from the housing cover 20.

The current collecting plate 40 is connected with the positive electrode of the battery cell 30, and the current collecting plate 40 is insulated from the housing 10, the current collecting plate 40 and the housing cover 20, and then the current collecting plate 40 is welded with the bottom of the recess 51 of the pole 50, so that the pole 50 is positively charged. The negative electrode of the battery cell 30 is electrically connected to the bottom of the case 10, so that the case 10 is negatively charged, and the case 10 and the case cover 20 are both negatively charged because the electrode post 50 is insulated from the case cover 20 and the case 10 is connected to the case cover 20.

Compared with the prior art, the current collecting disc 40 is not connected with the shell 10 and the shell cover 20, so when the shell 10 and the shell cover 20 are packaged, namely, in the process of roll grooves and flanging, the current collecting disc 40 and the shell 10 do not slide relatively, the current collecting disc 40 is electrically connected with the pole 50 through welding, the welding connection position of the current collecting disc 40 and the pole 50 is not separated, poor contact and electrical failure are avoided, and the internal resistance and current carrying capacity of the battery cell are not influenced. In addition, since no metal scraps are generated and safety accidents are caused, the secondary battery 1 of the present utility model has high electrical safety performance.

It should be understood that, although in the present embodiment, the positive electrode of the battery cell 30 is oriented toward the case cover 20, and the negative electrode of the battery cell 30 is electrically connected to the bottom of the case 10, in another embodiment, the negative electrode of the battery cell 30 may be oriented toward the case cover 20, and the negative electrode is welded to the current collecting plate 40, and then the current collecting plate 40 is welded to the bottom of the recess 51 of the post 50, and the post 50 is negatively charged; the positive electrode of the battery cell 30 is electrically connected to the bottom of the housing 10, and the housing 10 is positively charged, which does not deviate from the scope of the present utility model, and those skilled in the art can set the battery cell according to actual needs.

Further, the housing 10 is electrically connected to the housing cover 20, and this arrangement can make the housing 10 and the housing cover 20 have the same polarity. For example, the housing 10 and the housing cover 20 may be connected by welding, or the housing 10 and the housing cover 20 may be fixedly connected by riveting, and those skilled in the art may perform the arrangement according to actual needs.

Further, as shown in FIG. 2, the thickness a of the groove bottom of the recess 51 is 0.1mm to 2mm. The welding of the bottom of the recess 51 of the pole 50 and the collecting plate 40 generally adopts a penetration welding mode, the thickness a of the bottom of the recess 51 is set to be greater than 0.1mm, the strength of the pole 50 can be ensured, the thickness a of the bottom of the recess 51 is set to be less than 2mm, and the welding method is suitable for the welding conditions of penetration welding or other welding modes, and can be set according to actual needs by one skilled in the art. The thickness a of the groove bottom of the recess 51 may be set to 0.1mm, 0.5mm, 1mm, 1.5mm or 2mm without departing from the scope of the present utility model. The penetration welding mode is adopted, the welding process is easy to control, and the thermal influence is smaller.

Further, fig. 3 shows an enlarged view of a portion of the connection of the housing 10 to the cover 20 of fig. 1, wherein the housing 10 includes a side wall 17 surrounding its closed end 16, the side wall 17 facing away from the closed end 16 being an open end 11, the outer wall of the cover 20 being provided with an insert groove 21, and the side wall 17 being operatively inserted into the insert groove 21. This kind of structure sets up rationally, and the person skilled in the art can set up according to actual need.

Fig. 4 shows another embodiment of the present utility model, and fig. 5 shows a partial enlarged view of the pole 50 of fig. 4, and as shown in fig. 5, the collecting tray 40 is partially protruded toward the pole 50 to form a boss 41, and the bottom of the recess 51 is welded to the boss 41. The boss 41 is arranged, when the current collecting disc 40 and the pole 50 are welded, a certain distance is reserved between the welded point position and the battery cell 30, the thermal influence on the battery cell 30 during welding is small, and the quality of the secondary battery 1 can be better ensured. Those skilled in the art can make the settings according to actual needs.

Preferably, as shown in connection with fig. 4 and 5, the collecting tray 40 further includes a body portion 42, and a boss 41 protrudes from the body portion 42 toward the bottom of the pole 50, the boss 41 separating the bottom of the pole 50 from the body portion 42. The lower surface of the main body 42 abuts against the upper surface of the battery cell 30, and presses the battery cell 30, so that the battery cell 30 cannot shake randomly in the housing 10, the boss 41 abuts against the recess 51, the boss 41 supports the recess 51 to be stably arranged on the housing cover 20, the pole 50 is not easy to collapse, the stability of the structure of the secondary battery 1 is guaranteed, and a person skilled in the art can set the secondary battery according to actual needs.

In addition, fig. 6 shows a partial enlarged view of the junction of the case 10 and the case cover 20 in fig. 4, and as shown in fig. 6, a portion of the side wall 17 of the case 10 higher than the battery cell 30 has an inner recess 14 recessed toward the inside of the case 10, and the case cover 20 is disposed on the inner recess 14. The inner recess 14 is convenient to process, separates the collecting tray 40 from the case cover 20, supports the case cover 20, and presses and holds the collecting tray 40 and the battery cells 30 below the collecting tray 40, so that the collecting tray is not easy to shake, and the structural stability of the secondary battery 1 is ensured.

Preferably, as shown in fig. 6, the wall surface of the inner recess 14 directly sandwiches the insulation 80 with the current collecting plate 40. The isolation insulator 80 is provided such that the current collecting plates 40 of different polarities are not in electrical communication with the case 10, thereby avoiding an internal short circuit of the secondary battery 1 and ensuring electrical safety of the secondary battery 1. It should be appreciated that insulating rubber washers or other insulators may be used for isolation insulator 80 without departing from the scope of the present utility model. The isolation insulator 80 may be a silicone pad or a plastic pad, among other components.

Further, as shown in fig. 6, the open end 11 is bent toward the upper side of the cover 20 to form a bent portion 15, and the bent portion 15 is pressed against the top of the cover 20. The bending part 15 can be used for fixing the shell cover 20, and the person skilled in the art can set the device according to actual needs. In addition, the bending portion 15 is welded to the top of the case cover 20, and may be provided according to actual needs by those skilled in the art.

Fig. 7 shows a secondary battery 1 according to still another embodiment of the present utility model, in which a support 70 for supporting a case cover 20 is sandwiched between a collecting tray 40 and the case cover 20 as shown in fig. 7. The support 70 serves to support the case cover 20 such that the case cover 20 is not easily collapsed, and the structural stability of the secondary battery 1 is ensured.

Further, the support member 70 is an insulating elastic support member 70, such as a rubber member or foam or other insulating elastic member. The arrangement not only can ensure that the shell cover 20 is not easy to collapse, but also insulates the collecting tray 40 from the shell cover 20, thereby avoiding short circuit caused by connection of the shell covers 20 with different polarities and the collecting tray 40, ensuring the electrical safety of the secondary battery 1, and being capable of being arranged according to actual needs by a person skilled in the art. It should be understood that, when the supporting member 70 is not made of an insulating material, an insulating member should be disposed between the supporting member 70 and the collecting tray 40 and/or between the supporting member 70 and the casing cover 20, so as to prevent the collecting tray 40 from conducting with the casing cover 20 with different polarities, thereby causing a short circuit and ensuring the electrical safety of the secondary battery 1.

Fig. 8 shows an enlarged view of a portion of the connection of the housing 10 to the cover 20 of fig. 7, with the open end 11 having a support deck 12 for the cover 20 as shown in fig. 8. The support deck 12 is capable of receiving a housing cover 20, which can be set by those skilled in the art as desired. It should be understood that the support table 12 may be omitted and the support of the cover 20 may be achieved by the support 70 without departing from the scope of the utility model.

Further, as shown in fig. 8, a portion of the side wall 17 of the housing 10 near the open end 11 is provided with a mounting groove, and the mounting groove is open toward the open end 11, into which the cover 20 is operatively inserted, the mounting groove having a groove bottom toward the open end 11, which is the support mesa 12. This arrangement allows the housing 10 to be partially cut away from the side facing the open end 11 to form a mounting slot, to which the cover 20 can be snapped and placed on the support table 12, as may be desired by a person skilled in the art.

Preferably, as shown in fig. 8, the top end of the side wall 17 of the housing 10 is flush with the top of the cover 20, the side wall 17 of the housing 10 encloses the side wall of the cover 20, and the housing 10 is welded to the cover 20, i.e., the open end of the housing 10 is welded to the cover 20. The arrangement is reasonable in construction, and can be set by a person skilled in the art according to actual needs.

Fig. 11 shows a schematic structural view of a secondary battery 1 according to still another embodiment of the present utility model, and fig. 12 shows a partially enlarged view of the junction of case 10 and case cover 20 in fig. 11. As shown in fig. 12, a portion of the side wall 17 of the case 10 higher than the battery cell 30 has an inner recess 14 toward the case 10, and the case cover 20 is disposed on the inner recess 14. The inner recess 14 is convenient to process, separates the collecting tray 40 from the case cover 20, supports the case cover 20, and presses and holds the collecting tray 40 and the battery cell, thereby ensuring the structural stability of the secondary battery 1.

Preferably, as shown in fig. 12, a separation insulator 80 is sandwiched between the wall surface of the inner recess 14 and the current collecting plate 40. The provision of the isolation insulator 80 can prevent the internal short circuit of the secondary battery 1 and ensure the electrical safety of the secondary battery 1. Insulating spacer 80 may be an insulating rubber gasket or other insulating member without departing from the scope of the utility model.

Further, as shown in fig. 12, the top end of the side wall of the case 10 is flush with the top of the case cover 20, and the case 10 is welded to the case cover 20. The arrangement is reasonable in construction, and can be set by a person skilled in the art according to actual needs.

Fig. 13 shows a schematic structural view of a secondary battery 1 according to another embodiment of the present utility model, and fig. 14 shows a partially enlarged view of the junction of case 10 and case cover 20 in fig. 13. As shown in fig. 13, a support 70 for supporting the case cover 20 is sandwiched between the collecting tray 40 and the case cover 20. The support 70 serves to support the case cover 20 such that the case cover 20 is not easily collapsed, and the structural stability of the secondary battery 1 is ensured.

Further, the support member 70 is an insulating elastic support member, and an insulating elastic member made of other materials such as rubber may be used. This arrangement ensures that the case cover 20 is not easily collapsed and prevents the internal short circuit of the secondary battery 1 caused by the connection of the case cover 20 to the collecting tray 40. It should be understood that the supporting member 70 may not be made of an insulating material, and an insulating member should be disposed between the supporting member 70 and the collecting tray 40 and/or between the supporting member 70 and the case cover 20, so as to prevent the conduction of the electric circuit between the collecting tray 40 and the case cover 20 and ensure the electrical safety of the secondary battery 1.

Fig. 9 shows a secondary battery 1 according to another embodiment of the present utility model, and fig. 10 shows a schematic structure of fig. 9 where a case 10 is coupled to a case cover 20. Preferably, as shown in fig. 10, a portion of the side wall 17 of the housing 10 near the open end 11 protrudes into the housing 10 to form a bump 13, and a side of the bump 13 facing away from the battery cell 30 is a supporting table 12. This arrangement is easy to manufacture and can be set by a person skilled in the art according to the actual needs.

Preferably, the housing 10 is welded to the cover 20. Those skilled in the art can make the settings according to actual needs.

While the preferred embodiments of the present utility model have been described in detail above, it should be understood that aspects of the embodiments can be modified, if necessary, to employ aspects, features and concepts of the various patents, applications and publications to provide yet further embodiments.

These and other changes can be made to the embodiments in light of the above detailed description. In general, in the claims, the terms used should not be construed to be limited to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of carrying out the utility model and that various changes in form and details may be made therein without departing from the spirit and scope of the utility model.

Claims (15)

1. A secondary battery, characterized by comprising:

the shell is provided with a closed end at one end and an open end at the other end;

a cover closing the open end of the housing;

the battery cell is arranged in the shell, a first pole of the battery cell faces the shell cover, a second pole of the battery cell faces the closed end of the shell, and the second pole is electrically connected with the bottom of the shell;

the current collecting disc is arranged in the shell, connected with the first pole of the battery cell and insulated with the shell cover and the shell;

the pole penetrates through the shell cover, one side of the pole, which is positioned outside the shell, comprises a recess, and the bottom of the recess is connected with the current collecting disc in a welding way; and

the first insulating piece is sleeved on the pole to separate the pole from the shell cover.

2. The secondary battery according to claim 1, wherein the case is electrically connected to the case cover.

3. The secondary battery according to claim 1, wherein the thickness of the bottom of the recess groove is 0.1mm-2mm.

4. The secondary battery according to claim 1, wherein the current collecting plate is at least partially protruded in a direction toward the electrode post to form a boss, and the bottom of the recess is welded to the boss.

5. The secondary battery according to claim 4, wherein the current collecting tray further comprises a body portion from which the boss protrudes toward the bottom of the post; and the boss separates the bottom of the pole from the body portion.

6. The secondary battery according to claim 1, wherein a support member for supporting the case cover is sandwiched between the collecting tray and the case cover.

7. The secondary battery according to claim 6, wherein the support member is an insulating elastic support member.

8. The secondary battery according to claim 1, wherein the open end has a support mesa for placing the case cover.

9. The secondary battery according to claim 8, wherein the case comprises: a side wall surrounding a closed end thereof, the side of the side wall facing away from the closed end being the open end;

the part of the side wall close to the opening end protrudes into the shell to form a lug, and one side of the lug, which is away from the battery cell, is the supporting table top; or (b)

The side wall is close to the part of the open end and is provided with a mounting groove, the shell cover is operably embedded into the mounting groove, the mounting groove is provided with a groove bottom facing the open end, and the groove bottom is the supporting table surface.

10. The secondary battery according to any one of claims 6 to 9, wherein the case body is welded to the case cover.

11. The secondary battery according to claim 1, wherein the case includes: a side wall surrounding a closed end thereof, the side of the side wall facing away from the closed end being the open end; an embedded groove is formed in the outer wall of the shell cover, and the side wall is operably embedded in the embedded groove.

12. The secondary battery according to claim 1, wherein the case includes: a side wall surrounding a closed end thereof, the side of the side wall facing away from the closed end being the open end; the side wall is higher than the part of the battery cell and is provided with an inner concave part facing the inner concave part of the shell, and the shell cover is arranged on the inner concave part.

13. The secondary battery according to claim 12, wherein the wall surface of the inner recess directly sandwiches a separation insulator with the current collecting tray.

14. The secondary battery according to claim 13, wherein the open end is bent toward the upper side of the case cover to form a bent portion, and the bent portion is pressed against the top of the case cover.

15. The secondary battery according to claim 14, wherein the bent portion is welded to the top of the case cover.