Secondary battery, manufacturing method therefor, and electronic apparatus

Abstract

A secondary battery, a manufacturing method therefor, and an electronic apparatus. The secondary battery comprises a casing, a pole assembly, and an electrode assembly. The electrode assembly is accommodated in the casing. The casing is provided with a first main wall, a second main wall, and a first side wall. The first main wall and the second main wall are oppositely arranged in a first direction. The first side wall is connected between the first main wall and the second main wall. The pole assembly comprises a pole, and the pole penetrates through the first side wall. The electrode assembly comprises a main body portion and a first tab group extending from the main body portion. The first tab group comprises at least two first tabs and at least two second tabs. The at least two first tabs are folded in the direction of the first main wall and stacked to form a first folded part. The at least two second tabs are folded in the direction of the second main wall and stacked to form a second folded part. The second folded part and the first folded part are both electrically connected to the pole. By means of the above solution, the volumetric energy density of the secondary battery can be improved.

Description

Secondary battery and manufacturing method thereof, and electronic device

[0001] This application claims priority to the prior application with application number 202410171485.4 filed with the State Intellectual Property Office of China on February 6, 2024, entitled “Secondary battery, manufacturing method thereof, and electronic device”. The contents of the above-mentioned prior application are incorporated into this text by introduction. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a secondary battery, a manufacturing method thereof, and an electronic device. Background Art

[0003] When assembling a multi-electrode secondary battery, after the multi-electrode tabs on the electrode assembly are welded to the poles, the multi-electrode tabs need to be bent 90 degrees to adjust the direction of the motor assembly into the shell, thereby completing the process of installing the electrode assembly into the shell. Specifically, first, the positive electrode sheet, the separator, and the negative electrode sheet need to be stacked or wound in sequence to form the main body of the electrode assembly; secondly, the multiple tabs exposed on the main body need to be flattened to form a flat and smooth tab group; then, the tab group is welded to the poles; finally, the main body is flipped 90 degrees as shown in Figure 1 and placed in the shell to complete the packaging. However, since each tab on the tab group is bent in the same direction, the total bending rebound force generated by the tab group after bending is large, resulting in the tab group occupying more space, and thus the volume energy density of the secondary battery is low.

[0004] Application Contents

[0005] The purpose of this application is to provide a secondary battery and a manufacturing method thereof, and an electronic device, aiming to improve the volume energy density of the secondary battery.

[0006] According to the first aspect of the present application, a secondary battery is provided, comprising: a shell, a pole assembly and an electrode assembly. The electrode assembly is accommodated in the shell. The shell has a first main wall, a second main wall and a first side wall. Along a first direction, the first main wall and the second main wall are arranged opposite to each other, and the first side wall is connected between the first main wall and the second main wall. The pole assembly includes a pole, and the pole is passed through the first side wall. The electrode assembly includes a main body and a first pole tab group extending from the main body. The first pole tab group includes at least two first pole tabs and at least two second pole tabs, at least two of the first pole tabs are gathered and stacked in the direction of the first main wall to form a first gathered portion, and at least two of the second pole tabs are gathered and stacked in the direction of the second main wall to form a second gathered portion, and the second gathered portion and the first gathered portion are both electrically connected to the pole.

[0007] In the secondary battery involved in the present application, since the total number of first pole tabs and the total number of second pole tabs are individually reduced compared with the total number of foil pole tab groups bent in the same direction, the sum of the bending rebound forces generated after at least two first pole tabs are bent and the sum of the bending rebound forces generated after at least two second pole tabs are bent also become smaller, thereby reducing the space of the first pole tab group in the third direction, thereby reducing the gap between the main body and the first side wall, and thereby improving the volume energy density of the secondary battery.

[0008] In one or more optional embodiments above, a gap is formed between the main body and the first side wall. The secondary battery includes a transition piece located in the gap, and the first and second retracted portions are electrically connected to the terminal via the transition piece.

[0009] The first and second retracted portions are electrically connected to the terminal post via an adapter. This simplifies assembly of the electrode assembly and the terminal post, improving secondary battery assembly efficiency. Furthermore, the terminal post, first and second retracted portions can be flexibly positioned to accommodate varying secondary battery usage requirements.

[0010] In one or more of the above optional embodiments, the adapter extends along the second direction. When viewed along the third direction, the projection of the first and second retracted portions are both spaced apart from the projection of the pole. Any two of the third, second, and first directions are perpendicular to each other.

[0011] In one or more of the above optional embodiments, the first retracted portion includes a first extension segment extending along the first direction. The second retracted portion includes a second extension segment extending in a direction opposite to the first direction. The first extension segment, the second extension segment, and the pole are all located on a surface of the adapter facing away from the main body. In other words, the first extension segment and the second extension segment are both located on the same side of the adapter. When viewed along the second direction, the first extension segment and the second extension segment may overlap with the pole, thereby further reducing the space occupied by the three components and, in turn, further reducing the gap between the main body and the first sidewall.

[0012] In one or more optional embodiments above, the first gathering portion includes a first curved section and a plurality of first protruding sections. A plurality of first protruding sections extend from the main body portion, and a plurality of first protruding sections converge toward the direction of the first main wall and are stacked in the third direction, and the first extension section is connected to the plurality of first protruding sections through the first curved section. The second gathering portion includes a second curved section and a plurality of second protruding sections. A plurality of second protruding sections extend from the main body portion, and a plurality of second protruding sections converge toward the direction of the second main wall and are stacked in the third direction, and the second extension section is connected to the plurality of second protruding sections through the second curved section. A plurality of first protruding sections, the first curved section, the first extension section, a plurality of second protruding sections, the second curved section, and the second extension section are collectively arranged to form an installation space, and part of the adapter is arranged in the installation space.

[0013] Since the at least two first pole tabs and the at least two second pole tabs are first bent in opposite directions and then approach and intersect with each other, the space occupied by the at least two first pole tabs and the space occupied by the at least two second pole tabs do not interfere with each other, and when observed along the first direction, the first bent section and the second bent section overlap. Therefore, in the third direction, the space occupied by the first pole tab group is reduced, and the volume energy density of the secondary battery can be further improved.

[0014] In one or more of the above optional embodiments, the second extension section is superimposed on the surface of the adapter facing away from the main body, and a portion of the first extension section is superimposed on the second extension section. Thus, any two of the second connecting portion, a portion of the first extension section, and the second extension section can fully contact each other, thereby reducing the resistance at the connection between the three.

[0015] In one or more of the above optional embodiments, along the first direction, the distance between the end of the first extension segment away from the first curved segment and the second curved segment is D1, measured in mm, and the thickness of the main body is T1, measured in mm, satisfying the following relationship: 0.1 mm ≤ D1 ≤ T1. D1 is limited to this numerical range because, without affecting the volumetric energy density of the secondary battery, the first extension segment is less affected by the bending rebound force of the first curved segment and has a smaller degree of warping, thereby leaving sufficient area for contact with the second connecting portion.

[0016] In one or more of the above optional embodiments, along the first direction, the distance between the end of the second extension segment away from the second curved segment and the first curved segment is D2 (in mm), and the thickness of the main body is T1 (in mm), satisfying the following: 0.1 mm ≤ D2 ≤ T1 / 2. Within this numerical range, D2 reduces assembly difficulty, improves connection reliability, and reduces space occupied in the third direction.

[0017] In one or more optional embodiments above, the adapter includes a conductive layer and an insulating layer, the insulating layer is formed on a surface of the conductive layer facing the first side wall, and the first extension section, the second extension section, and the pole are all provided on a surface of the conductive layer facing away from the main body.

[0018] In one or more optional embodiments above, the pole is fixed to the conductive layer by welding.

[0019] In one or more optional embodiments above, the first extension section is fixed to the conductive layer by welding.

[0020] In one or more optional embodiments above, the second extension section is fixed to the conductive layer by welding.

[0021] In one or more optional embodiments above, the insulating layer is made of an adhesive insulating material, and the insulating layer is adhesively fixed to the plurality of first extending segments and the plurality of second extending segments.

[0022] In one or more optional embodiments above, the adhesive insulating material includes at least one of polypropylene, polyethylene, butyl rubber, acrylic glue, modified polyolefin, copolymer of styrene and butadiene, and acrylic glue.

[0023] In one or more of the above optional embodiments, along the third direction, the thickness of the insulating layer is T2, 0.01 mm ≤ T2 ≤ 0.2 mm. Within this range, the overall structural strength of the adapter is maintained while the maximum thickness of the adapter can be less than or equal to the width of the installation space in the third direction. This configuration can further reduce the gap between the main body and the first sidewall.

[0024] In one or more of the above optional embodiments, the conductive layer is made of metal material.

[0025] In one or more optional embodiments above, the metal material includes one of aluminum, copper, nickel, titanium, copper-nickel alloy, aluminum-copper alloy, and stainless steel.

[0026] In one or more of the above optional embodiments, along the third direction, the conductive layer has a thickness T3, 0.05 mm ≤ T3 ≤ 2 mm. Within this range, the overall structural strength of the adapter is maintained while the maximum thickness of the adapter can be less than or equal to the width of the installation space in the third direction. This configuration can further reduce the gap between the main body and the first sidewall.

[0027] In one or more of the above optional embodiments, the second extension segment and the first extension segment are both superimposed on the surface of the adapter facing away from the main body. Furthermore, when viewed along the third direction, the projection of the second extension segment is spaced apart from the projection of the first extension segment. This creates a larger gap between the connection between the first extension segment, the second extension segment, and the adapter and the housing, thereby minimizing the risk of short circuits caused by contact between the connection segment and the housing when the secondary battery is impacted.

[0028] In one or more of the above optional embodiments, the shell is a metal shell.

[0029] In one or more of the above optional embodiments, the terminal assembly includes a first seal, the first seal being disposed in the housing and affixed to the first sidewall via the terminal. Because the first seal respectively blocks the gap between the terminal and the inner surface of the first sidewall, and the gap between the terminal and the terminal hole, the airtightness of the secondary battery is improved, reducing the possibility of electrolyte leakage to the external environment.

[0030] In one or more of the above optional embodiments, the terminal assembly includes a second seal, which is disposed outside the housing and affixed to the first sidewall via the terminal. Because the second seal can block the gap between the terminal and the outer surface of the first sidewall, the second seal and the first seal form a double protection, further improving the airtightness of the secondary battery and further reducing the possibility of electrolyte leakage to the external environment.

[0031] In one or more of the above optional embodiments, the pole assembly includes a conductive member, which is disposed outside the housing and affixed to the second seal through the pole. This arrangement has the advantages of, on the one hand, increasing the connection area between the pole and the external device, facilitating good electrical contact between the external device and the pole; and, on the other hand, acting as a gasket during the pole riveting process, more evenly distributing the force applied to the second seal, thereby reducing the risk of failure of the second seal due to stress concentration.

[0032] In one or more optional embodiments above, the ratio of the total number of the first tabs to the total number of the second tabs satisfies 1:1 to 1:5. Or

[0033] The ratio of the total number of the first electrode tabs to the total number of the second electrode tabs satisfies 1:1 to 5:1.

[0034] By limiting the ratio of the total number of first pole ears to the total number of second pole ears within this range, the difference between the total number of first pole ears and the total number of second pole ears is small, and the difference between the sum of the bending rebound forces generated after the multiple first pole ears are bent and the sum of the bending rebound forces generated after the multiple second pole ears are bent is small, thereby further reducing the gap between the main body and the first side wall, and further improving the volume energy density of the secondary battery.

[0035] According to a second aspect of the present application, there is provided a method for manufacturing a secondary battery, comprising the following steps:

[0036] S1. Provide a housing, the housing comprising a first main wall and a second main wall defining a cavity, and a first side wall connected between the first main wall and the second main wall;

[0037] S2. Prepare an electrode assembly, wherein the electrode assembly includes a main body and a first electrode tab group extending from the main body, wherein the first electrode tab group includes at least two first electrode tabs and at least two second electrode tabs;

[0038] S3. Pressing the first tab assembly together with the adapter, so that at least two of the first tabs are gathered toward the first main wall and overlapped to form a first gathered portion, and at least two of the second tabs are gathered toward the second main wall and overlapped to form a second gathered portion, and the adapter is electrically connected to the first gathered portion and the second gathered portion, respectively.

[0039] S4. Place the integral structure formed by the electrode assembly and the adapter in the shell, and then electrically connect the adapter to the pole on the shell, with the adapter being located in the gap between the main body and the first side wall.

[0040] According to a third aspect of the present application, an electronic device is provided, comprising the secondary battery described above, or a secondary battery manufactured according to the method for manufacturing the secondary battery described above.

[0041] Additional aspects and advantages of the embodiments of the present application will be described, shown, or explained in part in the following description through implementation of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] To more clearly illustrate the specific embodiments of this application or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0043] FIG1 is a schematic diagram of the steps of installing an electrode assembly into a housing in the related art;

[0044] FIG2 is a schematic structural diagram of a secondary battery provided in one embodiment of the present application;

[0045] FIG3 is an exploded view of the structure of the secondary battery shown in FIG2 ;

[0046] FIG4 is a partially enlarged cross-sectional view of the secondary battery shown in FIG2 along line AA;

[0047] FIG5 is a schematic structural diagram of the secondary battery shown in FIG2 without a housing cover;

[0048] FIG6 is a partially enlarged cross-sectional view of the secondary battery shown in FIG5 along line BB;

[0049] FIG7 is a schematic structural diagram of a secondary battery provided in another embodiment of the present application without a housing cover;

[0050] FIG8 is a partially enlarged cross-sectional view of the secondary battery shown in FIG7 along line CC;

[0051] FIG9 is a schematic structural diagram of a secondary battery provided in another embodiment of the present application without a housing cover;

[0052] FIG10 is a partially enlarged cross-sectional view of the secondary battery shown in FIG8 taken along line DD.

[0053] 10. Shell; 10a. Cavity; 10b. Gap; 11. Shell cover; 111. First main wall; 12. Shell container; 121. Second main wall; 122. First side wall; 12a. Pole hole; 123. Second side wall; 124. Third side wall; 125. Fourth side wall;

[0054] 20. Pole assembly; 21. Pole; 211. First connecting portion; 212. Column portion; 213. Second connecting portion; 22. First sealing member; 221. First sealing member body; 222. Raised portion; 22a. First through hole; 23. Second sealing member; 23a. Second through hole; 24. Conductive member; 24a. Third through hole;

[0055] 30. Electrode assembly; 301. Main body; 302. First tab group; 3021. First gathered portion; 30211. First extended section; 30212. First curved section; 30213. First extended section; 3022. Second gathered portion; 30221. Second extended section; 30222. Second curved section; 30223. Second extended section; 302a. First tab; 302b. Second tab;

[0056] 40. Adapter; 41. Conductive layer; 42. Insulating layer;

[0057] X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0059] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0060] In the description of this application, it should be noted that, unless otherwise specified or limited, the terms "mounted" and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0061] The term "perpendicular" is used to describe the ideal state between two components. In actual production or use, there may be a state that is approximately perpendicular between the two components. For example, combined with numerical descriptions, perpendicular can refer to the angle between two straight lines being in the range of 90°±10°, perpendicular can also refer to the dihedral angle between two planes being in the range of 90°±10°, and perpendicular can also refer to the angle between a straight line and a plane being in the range of 90°±10°. The two components described as "perpendicular" may not be absolute straight lines or planes, but may be roughly straight lines or planes. From a macroscopic perspective, a component can be considered a "straight line" or a "plane" if the overall extension direction is a straight line or a plane.

[0062] The term "parallel" is used to describe the ideal state between two components. In actual production or use, there may be a state of approximate parallelism between the two components. For example, combined with numerical descriptions, parallel can refer to the angle between two straight lines being in the range of 180°±10°, parallel can also refer to the dihedral angle between two planes being in the range of 180°±10°, and parallel can also refer to the angle between a straight line and a plane being in the range of 180°±10°. The two components described as "parallel" may not be absolute straight lines or planes, but may be roughly straight lines or planes. From a macroscopic perspective, a component can be considered a "straight line" or a "plane" if its overall extension direction is a straight line or a plane.

[0063] The technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0064] FIG2 is a schematic structural diagram of a secondary battery provided in one embodiment of the present application, and FIG3 is an exploded structural diagram of the secondary battery shown in FIG2 .

[0065] First, please refer to Figures 2 and 3 together. The secondary battery includes: a shell 10, a pole assembly 20 and an electrode assembly 30; wherein the shell 10 is a mounting support structure for the electrode assembly 30 and the pole assembly 20; the shell 10 is provided with a cavity 10a, and the electrode assembly 30 is accommodated in the cavity 10a; the pole assembly 20 is fixed to the shell 10; one pole of the electrode assembly 30 is electrically connected to the pole assembly 20, and the other pole of the electrode assembly 30 and the pole assembly 20 are configured to be electrically connected to an external device to realize the mutual conversion of chemical energy and electrical energy during charging and discharging of the secondary battery.

[0066] It should be noted that the mutual conversion of chemical energy and electrical energy during charging and discharging of the secondary battery mentioned here refers to the state of the secondary battery in a single situation.

[0067] For example, the external device is an electronic device such as a mobile phone, a smart watch or a wireless headset. The secondary battery can discharge the aforementioned electronic device through the pole 21 and the shell 10 to maintain the stable operation of the electronic device. At this time, the process of converting chemical energy into electrical energy occurs inside the secondary battery.

[0068] For another example, the external device is an electronic device such as AC power, energy storage capacitor, etc. The electronic device can charge the secondary battery through the pole 21 and the other pole of the electrode assembly 30. At this time, the process of converting electrical energy into chemical energy occurs inside the secondary battery.

[0069] In some embodiments, the secondary battery includes an electrolyte (not shown) disposed in the cavity 10 a , and the electrode assembly 30 is immersed in the electrolyte.

[0070] In some embodiments, the secondary battery is a hard case battery.

[0071] Regarding the housing 10 , in some embodiments, the housing 10 includes a first main wall 111 , a second main wall 121 , and a first side wall 122 that enclose and form a receiving cavity. The first main wall 111 and the second main wall 121 are disposed opposite each other along a first direction X. The first side wall 122 is located on the same side of the first main wall 111 and the second main wall 121 and is connected between the first main wall 111 and the second main wall 121 . The first side wall 122 is used for mounting the pole assembly 20 .

[0072] Next, the specific structure of the housing 10 will be described in conjunction with FIG. 3 . As shown in FIG. 3 , the housing 10 includes a housing container 12 and a housing cover 11 .

[0073] The housing container 12 is generally in the shape of a rectangular parallelepiped frame and includes not only the aforementioned first side wall 122, but also a second main wall 121, a second side wall 123, a third side wall 124, and a fourth side wall 125. The first side wall 122, the second side wall 123, the third side wall 124, and the fourth side wall 125 are curved and extend in the same direction from the four sides of the second main wall 121, and the first side wall 122, the second side wall 123, the third side wall 124, and the fourth side wall 125 are connected end to end in sequence. The second main wall 121, the first side wall 122, the second side wall 123, the third side wall 124, and the fourth side wall 125 collectively enclose a container cavity 10a with an open opening.

[0074] The shape of the shell cover 11 matches that of the housing container 12. It is connected to the first side wall 122, the second side wall 123, the third side wall 124, and the fourth side wall 125 to seal the opening of the cavity 10a. The shell cover 11 has the above-mentioned first main wall 111. The first main wall 111 and the second main wall 121 are arranged opposite each other along a first direction X, the second side wall 123 and the fourth side wall 125 are arranged opposite each other along a second direction Y, and the first side wall 122 and the third side wall 124 are arranged opposite each other along a third direction Z. Any two of the first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0075] In some embodiments, the first main wall 111 and the second main wall 121 are both larger portions of the housing 10. The first main wall 111 and the second main wall 121 are oppositely disposed along the first direction X. In other words, the first main wall 111 and the second main wall 121 are oppositely disposed along the thickness direction of the secondary battery.

[0076] In some embodiments, the second side wall 123 and the fourth side wall 125 are both the second largest area portion of the housing 10. The second side wall 123 and the fourth side wall 125 are disposed opposite each other along the second direction Y. In other words, the second side wall 123 and the fourth side wall 125 are disposed opposite each other along the length direction of the secondary battery.

[0077] In some embodiments, the first side wall 122 and the third side wall 124 are both portions of the area of ​​the second side wall 123 and the fourth side wall 125 of the housing 10. The first side wall 122 and the third side wall 124 are disposed opposite each other along the third direction Z. In other words, the first side wall 122 and the third side wall 124 are disposed opposite each other along the width direction of the secondary battery.

[0078] Of course, the shape of the housing 10 is not limited thereto and can vary with the shape of the electrode assembly 30, and can simply have a first sidewall 122, a second sidewall 123, and a third sidewall 124 that satisfy the above relationship. For example, in some embodiments, the electrode assembly 30 is prismatic or L-shaped, and the housing 10 is also prismatic or L-shaped to match the shape of the electrode assembly 30.

[0079] Furthermore, the connection method between the housing container 12 and the shell cover 11 can be adaptively adjusted according to actual usage requirements. For example, in some embodiments, the shell cover 11 is welded to the first side wall 122, the second side wall 123, the third side wall 124, and the fourth side wall 125. For another example, in other embodiments, the shell cover 11 is adhesively bonded to the first side wall 122, the second side wall 123, the third side wall 124, and the fourth side wall 125.

[0080] In addition, the material of the housing container 12 and / or the housing cover 11 is actually diverse and is not specifically limited in the embodiments of this application. It is sufficient that it can isolate the chamber 10a from the external environment, resist electrolyte corrosion, and have a certain structural strength. Examples of such materials include metals or thermoplastics.

[0081] Metal materials may include titanium, magnesium, stainless steel, nickel steel, carbon steel, and aluminum-manganese alloys. For example, the housing container 12 and the housing cover 11 are made of the same nickel steel, or are each stamped from nickel steel and stainless steel. When both the housing container 12 and the housing cover 11 are made of metal, the other electrode of the electrode assembly 30 can be electrically connected to the housing container 12 or the housing cover 11. In this case, the housing 10 becomes one electrode of the secondary battery for electrical connection to external devices.

[0082] Thermoplastics may include polycarbonate. When the shell container 12 and the shell cover 11 are both made of thermoplastics, the other pole of the electrode assembly 30 can also be electrically connected to an electrical connector with similar functions to the pole assembly 20 to achieve electrical conduction between the internal and external circuits of the secondary battery.

[0083] In some embodiments, as shown in FIG. 3 , the first side wall 122 defines a pole hole 12 a communicating with the cavity 10 a .

[0084] Regarding the pole assembly 20 , in some embodiments, the pole assembly 20 includes a pole 21 . The pole 21 is disposed on the third sidewall 124 and is electrically connected to one pole of the electrode assembly 30 .

[0085] Please refer to the example shown in Figure 6 in conjunction with Figure 3. The pole 21 includes a first connecting portion 211, a column portion 212 and a second connecting portion 213. The column portion 212 is inserted into the pole hole 12a. The first connecting portion 211 is integrally connected to the end of the column portion 212 extending outside the cavity 10a. The side surface of the first connecting portion 211 facing the cavity 10a is sealed with the first side wall 122, and the side surface of the first connecting portion 211 facing away from the cavity 10a is used for electrical connection with an external device. The second connecting portion 213 is integrally connected to the end of the column portion 212 extending into the cavity 10a. The side surface of the second connecting portion 213 facing away from the main body 301 of the electrode assembly 30 is sealed with the first side wall 122. The side surface of the second connecting portion 213 facing the main body 301 of the electrode assembly 30 is electrically connected to one pole of the electrode assembly 30.

[0086] In some embodiments, the projection of the first connecting portion 211 in the third direction Z and / or the projection of the column portion 212 in the third direction Z falls within the projection of the second connecting portion 213 in the third direction Z. As a result, the second connecting portion 213 has a larger size, and the contact area when one pole of the electrode assembly 30 is electrically connected to the second connecting portion 213 can also be increased accordingly, which is beneficial to improving the electrical contact stability between the electrode assembly 30 and the pole 21. For example, the shape of the second connecting portion 213 can be similar to that of the third side wall 124, and is roughly in the shape of a rectangular plate as shown in Figure 3. The first connecting portion 211 can be roughly in the shape of a circular plate as shown in Figure 3.

[0087] In some embodiments, the thickness of the second connection portion 213 in the third direction Z is 0.1 mm to 1 mm. This is because, if the thickness of the second connection portion 213 in the third direction Z is less than 0.1 mm, the structural strength of the second connection portion 213 is limited, which can easily affect the structural reliability of the electrode 21. If the thickness of the second connection portion 213 in the third direction Z is greater than 1 mm, the processing difficulty of the electrode 21 and one pole of the electrode assembly 30 increases, which can easily affect the connection reliability of the second connection portion 213 and one pole of the electrode assembly 30. Therefore, the thickness of the second connection portion 213 in the third direction Z is limited to this numerical range, so that the electrode 21 has better structural reliability and improves the connection reliability of the electrode 21 and the electrode assembly 30. Furthermore, the thickness of the second connection portion 213 in the third direction Z is 0.25 mm to 0.5 mm.

[0088] In some embodiments, the terminal 21 can be riveted and fixed to the first side wall 122. Specifically, the second connecting portion 213 of the terminal 21 can be a predetermined rectangular plate, and the column portion 212 can be a predetermined cylindrical shape. After one end of the column portion 212 away from the second connecting portion 213 passes through the terminal hole 12a in a direction opposite to the third direction Z and partially extends out of the terminal hole 12a, pressure is applied to the terminal 21 to perform riveting, so that the portion of the column portion 212 extending out of the terminal hole 12a is deformed and expanded into the first connecting portion 211 under pressure, thereby causing the first connecting portion 211 and the second connecting portion 213 to abut against the first side wall 122 respectively.

[0089] It is understood that the material of the terminal 21 is diverse and is not specifically limited in the embodiments of this application. It suffices to satisfy the requirements of conductivity, electrolyte corrosion resistance, and workability. Examples of such materials include aluminum, copper, nickel, titanium, copper-nickel alloys, aluminum-copper alloys, and stainless steel. For example, the terminal 21 is made of a copper-aluminum composite material.

[0090] In some embodiments, the pole assembly 20 includes a first seal 22 . The first seal 22 is disposed on the housing 10 . The first seal 22 is attached to the first side wall 122 through the pole 21 .

[0091] Please refer to the examples shown in Figures 5 to 8 in conjunction with Figure 3. The pole assembly 20 includes a first seal 22, which includes a first seal body 221 and a raised portion 222 protruding from a side surface of the first seal body 221. The first seal body 221 is arranged between the second connecting portion 213 and the first side wall 122, and is respectively attached to the second connecting portion 213 and the inner surface of the first side wall 122. The raised portion 222 is provided with a first through hole 22a that passes through it and the first seal body 221. The column portion 212 can pass through the first through hole 22a to attach the raised portion 222 to the inner circumferential surface of the pole hole 12a, thereby achieving a sealed connection between the pole 21 and the inner surface of the first side wall 122. Since the first sealant 22 respectively blocks the gap between the terminal 21 and the inner surface of the first side wall 122 and the gap between the terminal 21 and the terminal hole 12a, the airtightness of the secondary battery can be improved, and the leakage of electrolyte to the external environment can be reduced.

[0092] As shown in Figure 6 or Figure 8, in some embodiments, the projection of the second connection part 213 in the third direction Z is located within the projection of the first sealing body 221 in the third direction Z, that is, the size of the first sealing body 221 is larger than the size of the second connection part 213. When the pole 21 and the shell 10 are both made of metal materials, the first seal 22 can be made of insulating material. The second connection part 213 is blocked on all sides by the first seal 22, thereby improving the situation where the second connection part 213 and the shell 10 are in contact and short-circuited when the secondary battery is impacted. For example, the shape of the first sealing body 221 can be adapted to the shape of the second connection part 213, and is also roughly in the shape of a rectangular plate as shown in Figure 5 or Figure 7.

[0093] It is understood that the material of the first sealing member 22 is actually diverse and is not specifically limited in the embodiments of this application, as long as it can meet the requirements of electrolyte corrosion resistance, insulation and workability. Examples of such materials include plastic adhesives, insulating rubbers, etc.

[0094] Plastic adhesives include, but are not limited to, hot melt adhesive. If the first sealant 22 is made of hot melt adhesive, the adhesive can be applied to the contact surface between the pole 21 and the third side wall 124. The adhesive is then heated until the adhesive melts and evenly applied to the contact surface. After the adhesive cools, it solidifies and forms the first sealant 22, tightly connecting the pole 21 and the third side wall 124. Insulating rubber includes, but is not limited to, butyl rubber.

[0095] If the first sealing member 22 is made of butyl rubber, the first sealing member 22 processed into a predetermined shape can be inserted into the pole hole 12a, and then the un-riveted pole 21 is passed through the first through hole 22a and riveted to ensure that the pole 21, the first sealing member 22 and the third side wall 124 are tightly connected together.

[0096] Please refer to the examples shown in Figures 5 to 8 in conjunction with Figure 3. In some embodiments, the pole assembly 20 includes a second seal 23, which is provided outside the housing 10 and is attached to the third side wall 124 through the pole 21.

[0097] The second sealing member 23 is provided with a second through hole 23a extending through its two opposite surfaces. The column portion 212 can sequentially pass through the first through hole 22a and the second through hole 23a. Under the pressure of the pole 21, the surface of the second sealing member 23 facing the cavity 10a abuts against the first side wall 122, and the surface of the second sealing member 23 facing away from the cavity 10a abuts against the first connecting portion 211. Because the second sealing member 23 can block the gap between the pole 21 and the outer surface of the first side wall 122, the second sealing member 23 and the first sealing member 22 form a double protection, which can further improve the airtightness of the secondary battery and further reduce the occurrence of electrolyte leakage to the external environment.

[0098] As shown in FIG6 , in some embodiments, the projection of the first connection portion 211 in the third direction Z is located within the projection of the second seal 23 in the third direction Z, that is, the size of the second seal 23 is larger than the size of the first connection portion 211. When the pole 21 and the shell 10 are both made of metal materials, the second seal 23 can be made of insulating material. The first connection portion 211 is blocked on all sides by the second seal 23, which can further improve the situation where the first connection portion 211 and the shell 10 are in contact and short-circuited when the secondary battery is impacted. For example, the second seal 23 is roughly in the shape of a long strip as shown in FIG3 .

[0099] For example, the second sealing member 23 may be made of insulating rubber such as butyl rubber.

[0100] Please refer to the examples shown in Figures 5 to 8 in conjunction with Figure 3. In some embodiments, the pole assembly 20 includes a conductive member 24. The conductive member 24 is provided outside the housing 10. The conductive member 24 is attached to the second sealing member 23 through the pole 21.

[0101] The conductive member 24 is generally in the form of a sheet, and is provided with a third through hole 24a. The column portion 212 can sequentially pass through the first through hole 22a, the second through hole 23a, and the third through hole 24a. Under the pressure of the pole 21, the surface of the second sealing member 23 facing away from the cavity 10a is pressed against the first connecting portion 211 through the conductive member 24. The advantage of this arrangement is that, on the one hand, the presence of the conductive member 24 increases the connection area between the pole 21 and the external device, making it easier for the external device to maintain good electrical contact with it; on the other hand, during the riveting process of the pole 21, the conductive member 24 can act as a gasket, making the force area of ​​the second sealing member 23 more balanced, thereby improving the situation where the second sealing member 23 fails due to stress concentration.

[0102] In some embodiments, the surface of the second sealing member 23 facing away from the cavity 10a is provided with a retaining groove (not shown) that matches the shape of the conductive member 24. The bottom of the retaining groove is provided with the aforementioned third through hole 24a, and the conductive member 24 is embedded in the retaining groove. This arrangement can prevent errors and thus improve the assembly efficiency of the secondary battery.

[0103] It should be noted that the first seal 22, the second seal 23, and the conductive member 24 in the terminal assembly 20 do not necessarily need to be present simultaneously. Any of the three can exist alone or in combination, provided that the charging and discharging of the secondary battery is not affected. It is also understood that the specific shapes of the terminal 21, the first seal 22, the second seal 23, and the conductive member 24 can also be other regular shapes besides those shown in FIG3 , and no further examples will be given here.

[0104] For the electrode assembly 30, in some embodiments, the electrode assembly 30 includes multiple first pole pieces (not shown), multiple isolation membranes (not shown), and multiple second pole pieces (not shown) having different polarity from the first pole pieces. The multiple first pole pieces and the multiple second pole pieces are alternately stacked, and adjacent first pole pieces and second pole pieces are separated by isolation membranes to form a stacked structure.

[0105] Of course, the electrode assembly 30 may also be any type of electrode assembly 30 other than this stacked structure, as long as it can achieve the charge and discharge functions of the secondary battery. For example, in other embodiments, the electrode assembly 30 may include a first electrode sheet, a separator, and a second electrode sheet, which are stacked and wound in sequence to form a wound structure.

[0106] For ease of description, the following embodiments are all described as an example in which the first electrode is a positive electrode and the second electrode is a negative electrode.

[0107] In some embodiments, the first electrode sheet includes a first electrode sheet body (not shown) and a plurality of tabs (not shown) spaced apart from the first electrode sheet body. The first electrode sheet body includes a first current collector (not shown) and a first active material layer (not shown). The first active material layer is coated on at least one surface of the first current collector. The plurality of tabs of the first electrode sheet are all connected to the first current collector and extend outward from one side of the first current collector body. The plurality of tabs serve as one pole of the electrode assembly 30 and are electrically connected to the electrode post assembly 20.

[0108] It is understood that the various embodiments of the present application do not specifically limit the connection method between the electrode tab of the first electrode sheet and the first current collector. For example, in some embodiments, the electrode tab is integrally connected to the first current collector. During implementation, the electrode tab and the first current collector can be die-cut from a complete foil. For example, in other embodiments, the electrode tab and the first current collector are welded. During implementation, a portion of the first active material layer can be scraped off from the first current collector coated with the first active material layer, and then a single electrode tab can be fixed to the exposed surface of the first current collector by, but not limited to, laser welding.

[0109] As an example, the first current collector includes, but is not limited to, one or more conductive metal sheets such as aluminum mesh, aluminum foil, and copper foil.

[0110] As an example, the first active material layer may include, but is not limited to, one or more of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese oxide, lithium nickel oxide, lithium manganese iron phosphate, lithium vanadium phosphate, lithium iron phosphate, and lithium-rich manganese-based materials.

[0111] In some embodiments, the second pole piece includes a second pole piece body (not shown) and a plurality of tabs (not shown) spaced apart from the second pole piece body. The second pole piece body includes a second current collector (not shown) and a second active material layer (not shown). The second active material layer is coated on at least one surface of the second current collector. The plurality of tabs of the second pole piece are all connected to the second current collector, and the plurality of tabs extend outward from one side of the second current collector. The plurality of tabs serve as the other pole of the electrode assembly 30 and are electrically connected to the housing 10.

[0112] It is understood that the embodiments of the present application do not specifically limit the connection method between the electrode tab of the second electrode sheet and the second current collector. Since the connection method between the electrode tab of the second electrode sheet and the second current collector is similar to the connection method between the first electrode tab 302a and the first current collector, the specific connection method between the first electrode tab 302a and the first current collector can be referred to above and will not be described in detail here.

[0113] As an example, the second current collector may include, but is not limited to, one or two of conductive metal sheets such as nickel foil and copper foil.

[0114] As an example, the second active material layer may include, but is not limited to, one or more of artificial graphite, natural graphite, soft carbon, hard carbon, graphene, mesocarbon microbeads, silicon-based materials, tin-based materials, lithium carbonate, or other metals capable of forming an alloy with lithium.

[0115] Next, the specific structure of the electrode assembly 30 will be described in conjunction with FIG. 3 to FIG. 8 . Please continue to refer to the examples shown in FIG. 3 to FIG. 8 .

[0116] Continuing with the example shown in FIG. 4 , the electrode assembly 30 includes a main body 301 and a first electrode tab group 302 extending from the main body 301. The main body 301 is housed within the cavity 10a and defines a gap 10b between the main body 301 and the third sidewall 124. The first electrode tab group 302 extends into the gap 10b from an end of the main body 301 proximal to the third sidewall 124. The first electrode tab group 302 includes at least two first electrode tabs 302a and at least two second electrode tabs 302b. The at least two first electrode tabs 302a are stacked and converge toward the first sidewall 122 to form a first converged portion 3021. The at least two second electrode tabs 302b are stacked and converge toward the second sidewall 123 to form a second converged portion 3022. Both the second converged portion 3022 and the first converged portion 3021 are electrically connected to the electrode post 21. The main body 301 is formed by alternately stacking a plurality of first pole piece bodies, a plurality of isolation membranes, and a plurality of second pole piece bodies, and the first tab group 302 is composed of the tabs of the plurality of first pole pieces.

[0117] In the secondary battery involved in the present application, since the total number of the first pole tabs 302a and the total number of the second pole tabs 302b are reduced compared with the total number of the foil pole tab group bent in the same direction in the related art, the sum of the bending rebound forces generated after the bending of at least two first pole tabs 302a and the sum of the bending rebound forces generated after the bending of at least two second pole tabs 302b are also reduced, thereby reducing the space of the first pole tab group 302 in the third direction Z, thereby reducing the gap 10b between the main body 301 and the first side wall 122, and thereby improving the volume energy density of the secondary battery.

[0118] In some embodiments, the ratio of the total number of first electrode tabs 302a to the total number of second electrode tabs 302b satisfies a range of 1:1 to 1:5. This is because if the ratio of the total number of first electrode tabs 302a to the total number of second electrode tabs 302b exceeds 1:5, it means that the total bending resilience force generated after bending of the first electrode tab group 302 is reduced slightly, and the space occupied by the first electrode tab group 302 is not significantly reduced. Therefore, by limiting the ratio of the total number of first electrode tabs 302a to the total number of second electrode tabs 302b to within this range, the difference between the total number of first electrode tabs 302a and the total number of second electrode tabs 302b is small, and the difference between the total bending resilience force generated after bending of multiple first electrode tabs 302a and the total bending resilience force generated after bending of multiple second electrode tabs is small. As a result, the gap 10b between the main body 301 and the first sidewall 122 is further reduced, and the volume energy density of the secondary battery is further improved.

[0119] For example, the ratio of the total number of first electrode tabs 302a to the total number of second electrode tabs 302b is specifically within the range defined by any two of 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.5, 1:2, 1:3, 1:4, and 1:5. Furthermore, the ratio of the total number of first electrode tabs 302a to the total number of second electrode tabs 302b is 1:1.

[0120] Alternatively, the ratio of the total number of the first electrode tabs 302a to the total number of the second electrode tabs 302b may also satisfy 1:1 to 5:1. Based on the similar effects as those in the above embodiment, no further description is given here.

[0121] As shown in Figures 4, 6, or 8, in some embodiments, the first converged portion 3021 includes a first extension segment 30213, a first curved segment 30212, and a plurality of first protruding segments 30211. The plurality of first protruding segments 30211 are electrically connected to the main body 301. The plurality of first protruding segments 30211 converge toward the first main wall 111 and are stacked in the third direction Z. The first extension segment 30213 is integrally connected to the plurality of first protruding segments 30211 via the first curved segment 30212. The first extension segment 30213 is electrically connected to the surface of the second connecting portion 213 facing the main body 301. Among them, the multiple first protruding sections 30211 are parts of at least two first pole tabs 302a extending into the gap 10b and connected to each other, the first bent section 30212 is a part of at least two first pole tabs 302a connected to each other and bent as a whole relative to the multiple first protruding sections 30211, and the first extension section 30213 is a part of at least two first pole tabs 302a connected to each other and extending toward the second main wall 121.

[0122] The second converged portion 3022 includes a second extension section 30223, a second curved section 30222, and multiple second protruding sections 30221. The multiple second protruding sections 30221 are electrically connected to the main body 301. The multiple second protruding sections 30221 converge toward the second main wall 121 and are stacked in the second direction Y. The second extension section 30223 is integrally connected to the multiple second protruding sections 30221 via the second curved section 30222. The second extension section 30223 is electrically connected to the surface of the second connecting portion 213 facing the main body 301. The multiple second protruding sections 30221 are the portions of at least two second tabs 302b that extend into the gap 10b and connect to each other. The second curved section 30222 is the portion of at least two second tabs 302b that connects to each other and bends integrally relative to the multiple second protruding sections 30221. The second extension section 30223 is the portion of at least two second tabs 302b that connects to each other and extends toward the first main wall 111.

[0123] By adopting the above technical solution, at least two first pole tabs 302a and at least two second pole tabs 302b are first bent in opposite directions and then approach each other and intersect, so that the space occupied by the bent at least two first pole tabs 302a and the space occupied by the bent at least two second pole tabs 302b do not interfere with each other, and when observed along the first direction X, the first curved section 30212 and the second curved section 30222 overlap, thereby reducing the space occupied by the first pole tab group 302 in the third direction Z, and further improving the volume energy density of the secondary battery.

[0124] It should be noted that when the thickness of the electrode assembly 30 in the third direction Z is less than 4 mm, the ends of the tabs of the multiple first electrode sheets away from the main body 301 need to be trimmed. After trimming, the overlapping areas of the tabs of any two adjacent electrode sheets provide better electrical connection reliability. However, when the thickness of the electrode assembly 30 in the third direction Z is greater than or equal to 4 mm, the ends of the tabs of the multiple first electrode sheets away from the main body 301 may be trimmed based on actual usage requirements.

[0125] In some embodiments, the second connection portion 213, a portion of the first extension section 30213, and the second extension section 30223 are stacked in sequence, so that any two of the second connection portion 213, a portion of the first extension section 30213, and the second extension section 30223 can fully contact each other, thereby reducing the resistance at the connection between the three.

[0126] Furthermore, the second connecting portion 213, a portion of the first extension section 30213, and the second extension section 30223 are fixed together by welding. Since the second connecting portion 213, a portion of the first extension section 30213, and the second extension section 30223 are stacked in sequence, there is no need to weld the first extension section 30213 and the second extension section 30223 to the second connecting portion 213 separately, thereby reducing the number of welding operations and improving the production efficiency of the secondary battery.

[0127] As shown in FIG3 , in some embodiments, along the first direction X, the distance between the end of the first extension section 30213 away from the first curved section 30212 and the second curved section 30222 is D1 (in mm), and the thickness of the main body 301 in the first direction X is T1 (in mm), and both satisfy the following relationship: 0.1 mm ≤ D1 ≤ T1. D1 is limited to this numerical range because, without affecting the volumetric energy density of the secondary battery, the first extension section 30213 is less affected by the bending rebound force of the first curved section 30212 and has a smaller degree of warping, thereby leaving sufficient area for contact with the second connecting portion 213.

[0128] Continuing with FIG3 , in some embodiments, along the first direction X, the distance D2 (in mm) between the end of the second extension section 30223 distal from the second curved section 30222 and the first curved section 30212 satisfies the following relationship: 0.1 mm ≤ D2 ≤ T1 / 2. D2 is limited to this numerical range because, if D2 < 0.1 mm, the length of the second extension section 30223 is approximately the same as the thickness of the main section 301 along the first direction X, potentially interfering with the first curved section 30212, increasing assembly difficulty and occupying more space in the third direction Z. If D2 > T1 / 2, the first extension section 30213 is significantly affected by the bending rebound force of the first curved section 30212, resulting in a greater degree of warpage. This complicates assembly and reduces connection reliability. Therefore, when D2 is within this numerical range, the difficulty of assembling the two components can be reduced, the connection reliability can be improved, and the occupied space in the third direction Z can be reduced. For example, 0.3 mm ≤ D2 ≤ 1.5 mm.

[0129] Of course, the connection method of the second connecting portion 213, the first extension section 30213, and the second extension section 30223 is not limited to this, and it is sufficient that all of them are electrically conductive with the second connecting portion 213. For example, in other embodiments, the second connecting portion 213, a portion of the second extension section 30223, and the first extension section 30213 are sequentially stacked. For another example, in other embodiments, the first extension section 30213 and the second extension section 30223 are respectively in contact with the second connecting portion 213, and when viewed along the third direction Z, the projection of the first extension section 30213 and the projection of the second extension section 30223 are separated.

[0130] As shown in Figures 3 to 10, in some embodiments, the secondary battery includes an adapter 40, through which the first extension section 30213 and the second extension section 30223 are electrically connected to the second connection portion 213. This simplifies the assembly of the electrode assembly 30 and the terminal post 21, thereby improving the assembly efficiency of the secondary battery. Furthermore, the terminal post 21, the first retracted portion 3021, and the second retracted portion 3022 can be flexibly arranged to meet the different usage requirements of the secondary battery.

[0131] In some embodiments, as shown in Figure 5, Figure 7 or Figure 10, when observed along the third direction Z, the projection of the first gathering portion 3021 and the projection of the second gathering portion 3022 are both separated from the projection of the pole 21. In other words, the projection of the first extension section 30213 and the projection of the second extension section 30223 are both separated from the projection of the second connecting portion 213.

[0132] Specifically, a plurality of first protruding sections 30211 , a first curved section 30212 , a first extension section 30213 , a plurality of second protruding sections 30221 , a second curved section 30222 and a second extension section 30223 are collectively arranged to form an installation space.

[0133] The adapter 40 is a thin plate-like structure that extends generally along the second direction Y. A portion of the adapter 40 is electrically connected to the surface of the second connecting portion 213 facing the main body 301. Another portion of the adapter 40 extends through the installation space and is electrically connected to the surface of the second extension section 30223 facing the main body 301. The surface of the second extension section 30223 facing away from the main body 301 is electrically connected to a portion of the first extension section 30213. Of course, the adapter 40 can also be electrically connected to the surface of the first extension section 30213 facing away from the main body 301. In this case, the second extension section 30223 and the first extension section 30213 are both superimposed on the surface of the adapter 40 facing away from the main body 301. Furthermore, when viewed along the third direction Z, the projection of the second extension section 30223 is spaced apart from the projection of the first extension section 30213. Therefore, the gap between the connection portion between the first extension section 30213, the second extension section 30223 and the adapter 40 and the housing 10 is larger, which can improve the situation where the connection portion contacts the housing 10 and causes a short circuit when the secondary battery is impacted.

[0134] Furthermore, please refer to the examples shown in Figures 5, 7, or 9 in conjunction with Figure 3. The adapter 40 includes a conductive layer 41 and an insulating layer 42. The side surface of the second extension section 30223 facing the main body 301 and the side surface of the second connection section 213 facing the main body 301 are both electrically connected to the conductive layer 41. The insulating layer 42 is formed on the surface of the conductive layer 41 facing the first side wall 122, and the insulating layer 42 is respectively fixed to the multiple first extension sections 30211 and the multiple second extension sections 30221. The insulating layer 42 has insulating properties and can isolate the current collector of different polarity from the first tab group 302 on the main body 301 from the first tab group 302, thereby reducing short circuits within the secondary battery. In addition, the insulating layer 42 can have higher structural strength than the conductive layer 41, which can reduce damage to the pole pieces in the main body 301 when the electrode assembly 30 is assembled into the shell.

[0135] The material of the conductive layer 41 is diverse and is not specifically limited in the embodiments of this application. Examples of such materials include metals, including aluminum, copper, nickel, titanium, a copper-nickel alloy, an aluminum-copper alloy, and stainless steel. For example, the conductive layer 41 can be made of aluminum, the same material as the first tab assembly 302.

[0136] In some embodiments, a side surface of the second extension section 30223 facing the main body 301 and a side surface of the second connection portion 213 facing the main body 301 are both welded and fixed to the conductive layer 41 .

[0137] The material of the insulating layer 42 is actually diverse and is not specifically limited in the embodiments of this application. Examples of such materials include adhesive insulating materials and non-adhesive insulating materials. The adhesive insulating material may include at least one of polypropylene, polyethylene, butyl rubber, acrylic glue, modified polyolefin, a copolymer of styrene and butadiene, and acrylic glue.

[0138] In some embodiments, the insulating layer 42 is bonded and fixed to the first extension segments 30211 and the second extension segments 30221. Of course, the insulating layer 42 can also be suspended above the first extension segments 30211 and the second extension segments 30221.

[0139] In some embodiments, the thickness T2 of the insulating layer 42 in the third direction Z is 0.01 mm ≤ T2 ≤ 0.2 mm, and the thickness T3 of the conductive layer 41 in the third direction Z is 0.05 mm ≤ T3 ≤ 2 mm. Within this range, the overall structural strength of the adapter 40 is maintained while the maximum thickness of the adapter 40 can be less than or equal to the width of the installation space in the third direction Z. This configuration can further reduce the gap 10b between the main body 301 and the first sidewall 122. Preferably, 0.02 mm ≤ T2 ≤ 0.15 mm, and 0.15 mm ≤ T3 ≤ 0.35 mm.

[0140] As shown in Figures 7 and 8, in order to facilitate the welding and fixing of the side surface of the second connecting part 213 facing the main body 301 with the conductive layer 41, in some embodiments, a blind hole is opened in the pole 21, and the blind holes pass through the first connecting part 211 and the main body 301 respectively, but do not pass through the second connecting part 213. During laser welding, the laser penetrates from the outside to the cavity 10a along the blind hole to complete the welding and fixing of the side surface of the second connecting part 213 facing the main body 301 with the conductive layer 41.

[0141] Alternatively, as shown in FIG9 or FIG10 , in other embodiments, the structure of the pole 21 is the same as that of the pole 21 in the aforementioned technical solution, but the setting direction of the pole 21 may be opposite to the setting direction of the pole 21 in the aforementioned technical solution. During implementation, the end of the column portion 212 away from the first connecting portion 211 passes through the pole hole 12a from the third direction Z and partially extends into the cavity 10a. Pressure is applied to the pole 21 to perform riveting, so that the portion of the column portion 212 extending into the pole hole 12a is deformed and expanded into the second connecting portion 213 under pressure, thereby the second connecting portion 213 and the first connecting portion 211 respectively abut against the first side wall 122. At this time, the portion of the adapter 40 that does not penetrate the installation space only has the conductive layer 41. Therefore, the laser can penetrate the conductive layer 41 and the second connecting portion 213 to complete the welding and fixation of the side surface of the second connecting portion 213 facing the main body 301 to the conductive layer 41.

[0142] An embodiment of the present application provides a method for manufacturing a secondary battery, including the following steps.

[0143] In step S1 , a housing 10 is provided. The housing 10 includes a first main wall 111 , a second main wall 121 , and a first side wall 122 connected between the first main wall 111 and the second main wall 121 , which define a receiving cavity 10 a .

[0144] The housing 10 may include a housing container 12 and a housing cover 11. The housing container 12 defines a cavity 10a with an opening. The housing container 12 has a second main wall 121 and a first side wall 122 that define the cavity 10a. The housing cover 11 is connected to the opening and seals it. The housing cover 11 has a first main wall 111 that defines the cavity 10a. The first main wall 111 and the second main wall 121 are arranged opposite each other in a first direction X.

[0145] Step S2 , preparing an electrode assembly 30 , the electrode assembly 30 includes a main body 301 and a first electrode tab group 302 extending from the main body 301 , the first electrode tab group 302 including at least two first electrode tabs 302 a and at least two second electrode tabs 302 b .

[0146] The electrode assembly 30 includes a first electrode sheet, a second electrode sheet, and a separator disposed between the first and second electrode sheets. The first electrode sheet body, separator, and second electrode sheet body are alternately stacked to form a laminate structure, or stacked and wound into a wound structure. The first electrode sheet body, separator, and second electrode sheet body form a main body 301. Multiple tabs extending from the first electrode sheet body 301 form a first tab group 302.

[0147] In step S3, the adapter 40 presses the first electrode tab group 302 so that at least two first electrode tabs 302a are gathered and stacked toward the first main wall 111 to form a first gathered portion 3021, and at least two second electrode tabs 302b are gathered and stacked toward the second main wall 121 to form a second gathered portion 3022. The adapter 40 is electrically connected to the first gathered portion 3021 and the second gathered portion 3022, respectively.

[0148] In step S4 , the overall structure formed by the electrode assembly 30 and the adapter 40 is placed in the shell 10 , and the adapter 40 is electrically connected to the pole 21 on the shell 10 . The adapter 40 is located in the gap 10 b between the main body 301 and the first side wall 122 .

[0149] One embodiment of the present application further provides an electronic device comprising any of the above-mentioned secondary batteries. The electronic device of the present application may include, but is not limited to, a laptop computer, a pen-type computer, a mobile computer, an e-book player, a portable phone, a portable fax machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, an LCD television, a portable cleaner, a portable CD player, a mini-disc, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, an automobile, a motorcycle, a power-assisted bicycle, a lighting fixture, a toy, a game console, a clock, a power tool, a flashlight, a camera, a large household battery, and a lithium-ion capacitor.

[0150] The above description is merely an embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A secondary battery comprising a housing, a terminal assembly, and an electrode assembly, wherein the electrode assembly is housed in the housing, the housing having a first main wall, a second main wall, and a first side wall, wherein the first main wall and the second main wall are disposed opposite each other along a first direction, and the first side wall is connected between the first main wall and the second main wall, and the terminal assembly comprises a terminal, wherein the terminal is disposed through the first side wall; The electrode assembly includes a main body and a first electrode tab group extending from the main body, the first electrode tab group includes at least two first electrode tabs and at least two second electrode tabs, at least two of the first electrode tabs are gathered toward the first main wall and stacked to form a first gathered portion, at least two of the second electrode tabs are gathered toward the second main wall and stacked to form a second gathered portion, and the second gathered portion and the first gathered portion are both electrically connected to the electrode column.

2. The secondary battery according to claim 1, wherein A gap is formed between the main body and the first side wall; The secondary battery includes a switching element, the switching element is located in the gap, and the first and second retracted portions are electrically connected to the pole via the switching element.

3. The secondary battery according to claim 2, wherein The adapter extends along the second direction; When viewed along a third direction, a projection of the first gathered portion and a projection of the second gathered portion are both separated from a projection of the pole, wherein any two of the third direction, the second direction, and the first direction are perpendicular to each other.

4. The secondary battery according to claim 3, wherein The first gathering portion includes a first extension segment extending along the first direction, and the second gathering portion includes a second extension segment extending in a direction opposite to the first direction; The first extension section, the second extension section, and the pole are all arranged on a surface of the adapter facing away from the main body.

5. The secondary battery according to claim 4, wherein The first gathered portion includes a first curved section and a plurality of first extended sections, the plurality of first extended sections extending from the main portion, the plurality of first extended sections gathered toward the first main wall and stacked in the third direction, and the first extension section connected to the plurality of first extended sections via the first curved section; The second gathered portion includes a second curved section and a plurality of second extended sections, the plurality of second extended sections extending from the main portion, the plurality of second extended sections gathered toward the second main wall and stacked in the third direction, and the second extended section connected to the plurality of second extended sections via the second curved section; The plurality of first protruding sections, the first curved section, the first extension section, the plurality of second protruding sections, the second curved section and the second extension section together enclose an installation space, and part of the adapter is disposed in the installation space.

6. The secondary battery according to claim 5, characterized in that The second extension section is overlapped on a surface of the adapter facing away from the main body, and a portion of the first extension section is overlapped on the second extension section.

7. The secondary battery according to claim 6, characterized in that Along the first direction, the distance between the end of the first extension section away from the first curved section and the second curved section is D1, the thickness of the main body is T1, and the following conditions are satisfied: 0.1 mm ≤ D1 ≤ T1; and / or Along the first direction, a distance D2 is provided between an end of the second extending section away from the second curved section and the first curved section, and a thickness of the main body is T1, satisfying the following: 0.1 mm ≤ D2 ≤ T1 / 2.

8. The secondary battery according to any one of claims 5 to 7, characterized in that: The adapter comprises a conductive layer and an insulating layer, wherein the insulating layer is formed on a surface of the conductive layer facing the first side wall; The first extension section, the second extension section and the pole are all arranged on a surface of the conductive layer away from the main body.

9. The secondary battery according to claim 8, characterized in that The secondary battery satisfies at least one of the following conditions: (1) The pole is welded and fixed to the conductive layer; (2) the first extension section is welded and fixed to the conductive layer; (3) The second extension section is welded and fixed to the conductive layer; (4) The insulating layer is made of a sticky insulating material, and the insulating layer is adhesively fixed to the plurality of first extension segments and the plurality of second extension segments; (5) Along the third direction, the thickness of the insulating layer is T2, 0.01 mm ≤ T2 ≤ 0.2 mm; (6) The conductive layer is made of metal material; (7) Along the third direction, the thickness of the conductive layer is T3, 0.05 mm ≤ T3 ≤ 2 mm.

10. The secondary battery according to claim 9, wherein The sticky insulating material includes at least one of polypropylene, polyethylene, butyl rubber, acrylic glue, modified polyolefin, copolymer of styrene and butadiene, and acrylic glue; The metal material includes one of aluminum, copper, nickel, titanium, copper-nickel alloy, aluminum-copper alloy, and stainless steel.

11. The secondary battery according to claim 5, wherein The second extension section and the first extension section are both superimposed on a surface of the adapter facing away from the main body; and When viewed along the third direction, a projection of the second extension section is separated from a projection of the first extension section.

12. The secondary battery according to any one of claims 1 to 11, characterized in that: The shell is a metal shell.

13. The secondary battery according to any one of claims 1 to 11, characterized in that: The pole assembly includes a first seal, which is provided on the housing and adheres to the first side wall through the pole.

14. The secondary battery according to claim 13, wherein: The pole assembly includes a second seal, which is arranged outside the housing and adheres to the first side wall through the pole.

15. The secondary battery according to claim 14, characterized in that The pole assembly includes a conductive member, which is arranged outside the shell and is attached to the second sealing member through the pole.

16. The secondary battery according to any one of claims 1 to 11, characterized in that: The ratio of the total number of the first electrode tabs to the total number of the second electrode tabs satisfies 1:1 to 1:5; or The ratio of the total number of the first electrode tabs to the total number of the second electrode tabs satisfies 1:1 to 5:

1.

17. A method for manufacturing a secondary battery according to any one of claims 2 to 11, characterized in that: The steps include: S1. Provide a housing, the housing comprising a first main wall and a second main wall defining a cavity, and a first side wall connected between the first main wall and the second main wall; S2. Prepare an electrode assembly, wherein the electrode assembly includes a main body and a first electrode tab group extending from the main body, wherein the first electrode tab group includes at least two first electrode tabs and at least two second electrode tabs; S3. Pressing the first tab assembly together with the adapter, so that at least two of the first tabs are gathered toward the first main wall and overlapped to form a first gathered portion, and at least two of the second tabs are gathered toward the second main wall and overlapped to form a second gathered portion, and the adapter is electrically connected to the first gathered portion and the second gathered portion, respectively. S4. Place the integral structure formed by the electrode assembly and the adapter in the shell, and then electrically connect the adapter to the pole on the shell, with the adapter being located in the gap between the main body and the first side wall.

18. An electronic device, characterized in that: A secondary battery comprising the secondary battery according to any one of claims 1 to 16, or a secondary battery manufactured by the method for manufacturing a secondary battery according to claim 17.

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