CN117790874A - Secondary battery and electricity utilization device - Google Patents

Secondary battery and electricity utilization device Download PDF

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Publication number
CN117790874A
CN117790874A CN202410140070.0A CN202410140070A CN117790874A CN 117790874 A CN117790874 A CN 117790874A CN 202410140070 A CN202410140070 A CN 202410140070A CN 117790874 A CN117790874 A CN 117790874A
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CN
China
Prior art keywords
wall
tab
secondary battery
main body
sealing part
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Pending
Application number
CN202410140070.0A
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Chinese (zh)
Inventor
马武
张国文
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Ningde Amperex Technology Ltd
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Ningde Amperex Technology Ltd
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Application filed by Ningde Amperex Technology Ltd filed Critical Ningde Amperex Technology Ltd
Priority to CN202410140070.0A priority Critical patent/CN117790874A/en
Publication of CN117790874A publication Critical patent/CN117790874A/en
Pending legal-status Critical Current

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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The application discloses secondary cell and power consumption device, it includes: a package bag, an electrode assembly and a first tab; the packaging bag comprises a main body part, a first top sealing part and a first side sealing part, wherein the main body part comprises a first top wall and a first side wall, the first top sealing part is connected to the first top wall and bends towards the first direction, the first side wall is located at one side of the first top wall along the second direction, the first side sealing part is connected to the first side wall, a first gap is formed between the first side sealing part and the first top sealing part along the second direction, a first tab comprises a first metal strip and first tab glue which is arranged around the first metal strip, one end of the first metal strip is electrically connected with the electrode assembly, the first tab glue is bonded to the packaging bag, and the other end of the first tab penetrates through the first tab glue and the first gap to extend out of the packaging bag. In this way, the secondary battery provided by the application is beneficial to improving the capacity of the secondary battery.

Description

Secondary battery and electricity utilization device
Technical Field
The present disclosure relates to battery technology, and more particularly, to a secondary battery and an electric device.
Background
In the related art, the top of the soft package battery is not folded to the top seal, which results in a larger occupied space of the battery head. In order to improve the situation, a design of the folded top seal may be considered, and specifically, the metal strip of at least one tab and the tab adhesive may be folded together along with the folding of the top seal portion. However, the tab adhesive has high hardness and is difficult to bend, and even if the tab adhesive bends, the tab adhesive occupies more space in the height direction of the battery, which is not beneficial to the capacity improvement of the secondary battery.
Disclosure of Invention
The purpose of the present application is to provide a secondary battery and an electric device, which aim to increase the capacity of the secondary battery.
According to a first aspect of the present application, there is provided a secondary battery including a package bag, an electrode assembly, and a first tab. The package includes a main body portion, a first top seal portion, and a first side seal portion. The electrode assembly is disposed within the body portion. The main body part comprises a first top wall and a first side wall, the first top sealing part is connected to the first top wall and bends towards a first direction, the first side wall is positioned on one side of the first top wall along a second direction, and the first side sealing part is connected to the first side wall, wherein the first direction is perpendicular to the second direction. And a first gap is formed between the first side sealing part and the first top sealing part along the second direction. The first tab comprises a first metal strap and first tab glue which is arranged around the first metal strap. One end of the first metal strap is electrically connected with the electrode assembly, the first tab glue is adhered to the packaging bag, and the other end of the first tab passes through the first tab glue and the first gap to extend out of the packaging bag.
In the secondary battery according to the present application, the first tab no longer protrudes from the first top seal portion, and thus the first top seal portion is folded without being affected by the hardness of the first tab adhesive. For the scheme that the first tab extends from the first top sealing part and is bent together with the first tab, the bending resilience force generated by folding of the first top sealing part is small, namely the warping degree of the first top sealing part is reduced, the occupied space of the first top sealing part in the third direction after bending is reduced, and the improvement of the battery capacity of the secondary battery is facilitated.
In one or more/alternative embodiments above, the body portion includes a second top wall. The second top wall connects the first top wall and the first side wall, respectively, and is recessed in a third direction relative to the first top wall. The third direction, the second direction and the first direction are perpendicular to each other. The package includes a second top seal. The second top sealing part is arranged on the second top wall, and the second top sealing part is connected with the first top sealing part and the first side sealing part. The other end of the first metal strip extends out of the packaging bag through the second top sealing part and the first gap.
In one or more/alternative embodiments above, the second top wall includes a first connecting wall and a second connecting wall. The second connecting wall is connected to the first top wall through the first connecting wall. The second connecting wall and the first top wall are arranged in parallel with respect to the first direction.
In one or more/alternative embodiments above, the first tab glue is disposed on the second top seal. And along a third direction, one end of the first tab adhesive exceeds one side edge of the second top sealing part. And when the first tab adhesive is observed along the second direction, the projection of the first tab adhesive beyond the edge part of one side of the second top sealing part coincides with the projection of the first top sealing part. The benefit that sets up like this lies in, in the distance that the first utmost point ear glued one side edge that has first utmost point ear glued of encapsulation on the wrapping bag surpassed, the head is owing to the high restriction of first utmost point ear glued, has partly head space extravagant, sets up first top seal portion and first utmost point ear glued and exists the coincidence along the third direction, the extravagant space of this part of utilization that can be better to improve the distance of energy density partly and offset by the space size that first top seal portion occupy in the third direction, thereby the secondary cell head space occupies further reduction, and then the capacity of secondary cell can further promote.
In one or more/alternative embodiments above, the second connecting wall is spaced apart from the first top seal by a distance S along the third direction from a surface of the first top wall facing away from the first top wall 1 . Along the third direction, the sum S of the distance between the end of the second top sealing part, which is close to the second connecting wall, and the end, which is far away from the second connecting wall, and the distance between the first tab adhesive and the edge part of the side, which is beyond the second top sealing part 2 。S 1 And S is 2 The method meets the following conditions: s is S 1 ≥S 2 . In this way, on the premise of less influence on the volume energy density of the secondary battery, the first tab adhesive does not need to be bent, so that the situation that the connection strength around the first tab adhesive is insufficient and liquid leakage caused by bending the first tab adhesive can be improved.
In one or more/alternative embodiments above, the package includes a second side seal. The body portion includes a second sidewall. The second side wall is positioned on the other side of the first top wall along the second direction, and the second side seal part is connected with the second side wall. And a second gap is formed between the second side sealing part and the first top sealing part along the first direction. The secondary battery includes a second tab. The second lug comprises a second metal belt and second lug adhesive wrapping the second metal belt. One end of the first metal strap is electrically connected with the electrode assembly, and the other end of the second tab penetrates through the second tab adhesive and the second gap to extend out of the packaging bag.
In one or more/alternative embodiments above, the body portion includes a third top wall. The third top wall connects the first top wall and the second side wall, respectively, and is recessed in a third direction relative to the first top wall. The third direction, the second direction and the first direction are perpendicular to each other. The package includes a third top seal. The third top sealing part is arranged on the third top wall and is connected with the first top sealing part and the second side sealing part. The other end of the second metal strip extends out of the packaging bag through the third top sealing part and the second gap.
In the above technical scheme, the second lug does not extend from the second top sealing part any more, so that the second lug is not influenced by the hardness of the second lug when the second top sealing part is folded, compared with the scheme that the second lug extends from the first top sealing part and is bent together with the first top sealing part, the bending resilience force generated by folding the first top sealing part is smaller, namely the warping degree of the first top sealing part is reduced, the occupied space of the first top sealing part in the third direction is reduced after the first top sealing part is bent, the occupied space of the head of the secondary battery is reduced, and the capacity of the secondary battery is further improved.
In one or more/alternative embodiments above, the third top wall includes a third connecting wall and a fourth connecting wall. The fourth connecting wall is connected with the first top wall through the third connecting wall. The fourth connecting wall and the first top wall are disposed in parallel with respect to the first direction.
In one or more/alternative embodiments above, the second ear glue is disposed on the third top seal. And along the third direction, one end of the second ear glue exceeds one side edge of the third top sealing part. Viewed along the second direction, the projection of the second ear glue beyond the edge part of one side of the third top sealing part is overlapped with the projection of the first top sealing part. So set up, in the distance that the second ear glue surpassed the one side edge of encapsulation had the second ear glue on the wrapping bag, partly apart from by the space size that first top seal portion occupy in the third direction offset to secondary cell head space occupies further reduces, and then the capacity of secondary cell can further promote.
In one or more/alternative embodiments above, the package has a first cavity and a second cavity in communication with the first cavity.
The electrode assembly includes an electrode assembly body and a protrusion integrally connected with the electrode assembly body. The electrode assembly body is accommodated in the first cavity, and the convex part is accommodated in the second cavity. One end of the first metal strip and one end of the second metal strip are electrically connected with the electrode assembly body. The electrode assembly includes a first electrode sheet, a second electrode sheet, and a separator separating the first electrode sheet and the second electrode sheet. The first pole piece comprises a first pole piece main body and a first protruding part integrally connected with the first pole piece main body. The second pole piece comprises a second pole piece body and a second protruding part integrally connected with the second pole piece body. The isolation diaphragm includes isolation diaphragm main part and with the third protruding portion of isolation diaphragm main part body coupling. The electrode assembly main body is formed by sequentially and alternately superposing the first pole piece main body, the isolating film main body and the second pole piece main body. The convex part is formed by sequentially and alternately superposing the first convex part, the third convex part and the second convex part.
In one or more of the above/alternative embodiments, a junction of the electrode assembly body and the first metal strip is disposed opposite the second top wall in the third direction. On the one hand, the gap between the convex portion and the first top sealing portion is shortened, so that the amount of free electrolyte accumulation in the partial region is reduced, and the occurrence of short circuit due to shrinkage of the separator generated by the separator where the amount of free electrolyte accumulation is excessive impacts the convex portion is improved. On the other hand, the first top sealing part is not influenced by the first metal belt and the first tab adhesive any more when being heat-sealed, and has stable connection strength after being heat-sealed. In still another aspect, the size of the first top sealing part extending outward is also reduced without being affected by the first metal tape and the first tab adhesive, whereby the volumetric energy density of the secondary battery is further improved.
In one or more of the above/alternative embodiments, a junction of the electrode assembly body and the second metal strip is disposed opposite the third top wall in the third direction. Based on the similar mechanism as described in the electrical connection of the first pole piece body and the first tab, the same effects as in the previous embodiments are also achieved, and will not be described in detail here. In addition, when the first tab and the second tab are respectively located at two opposite sides of the first top sealing portion along the second direction, even though the presence of the first space and the second space may reduce the capacity of the secondary battery, the capacity increased by the protruding portion is still greater than the sum of the reduced capacities of the two compared with the same-sized folded top sealing battery, i.e., the total capacity of the secondary battery can still be increased.
In one or more/alternative embodiments above, the number of third protrusions is at least two. And along the third direction, the end parts of at least two third protruding parts exceeding the second protruding parts are mutually connected and fixed to form a connecting part. The structure has the advantages that the upper limit of the maximum impact stress can be improved through the integral structure formed by connecting and fixing the third protruding parts, so that the situation that the isolating film is folded and shorted when free electrolyte impacts the isolating film of the protruding part is improved.
In one or more/alternative embodiments above, the length of the connecting portion in the second direction is 15mm to 120mm.
In one or more/alternative embodiments above, the second side seal is folded in the first direction.
In one or more/alternative embodiments above, the first side seal is folded in the first direction.
According to a second aspect of the present application, there is provided an electric device comprising the secondary battery as described above.
Additional aspects and advantages of embodiments of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of embodiments of the application.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are used in the description of the embodiments or the prior art will be briefly described below. Like elements or portions are generally identified by like reference numerals throughout the several figures. In the drawings, elements or portions thereof are not necessarily drawn to scale.
Fig. 1 is a schematic structural view of a secondary battery according to a first embodiment of the present application;
fig. 2 is a schematic structural view of another secondary battery provided in the first embodiment of the present application;
FIG. 3 is an enlarged view of a portion of FIG. 1 at a;
FIG. 4 is an enlarged view of a portion of FIG. 1 at b;
fig. 5 is a schematic view of the structure of the secondary battery shown in fig. 1, when the electrode assembly is not mounted to the package bag;
fig. 6 is a partial enlarged view of c in the secondary battery shown in fig. 5;
fig. 7 is a schematic view of a structure of the secondary battery shown in fig. 1 at another angle;
FIG. 8 is an enlarged view of a portion of FIG. 7 at d;
FIG. 9 is an enlarged view of a portion of FIG. 7 at e;
FIG. 10 is a cross-sectional view taken along line A-A of FIG. 1;
FIG. 11 is an enlarged view of a portion at f in FIG. 10;
fig. 12 is a schematic structural view of a secondary battery according to a second embodiment of the present application;
fig. 13 is a schematic view showing the structure of another secondary battery according to the second embodiment of the present application;
fig. 14 is another schematic structural view of the secondary battery shown provided in the second embodiment of the present application;
fig. 15 is a schematic view of still another structure of the secondary battery shown provided in the second embodiment of the present application;
FIG. 16 is a partial cutaway view at g in FIG. 15;
FIG. 17 is a partial cutaway view at h in FIG. 15;
FIG. 18 is a cross-sectional view taken along line B-B of FIG. 15;
FIG. 19 is an enlarged view of a portion of FIG. 18 at i;
fig. 20 is a structural exploded view of the secondary battery shown in fig. 12.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments.
Reference in the specification to "an embodiment" means 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 appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.
The term "vertical" is used to describe an ideal state between two components. In the actual production or use state, there may be an approximately vertical state between the two components. For example, in conjunction with the numerical description, perpendicular may refer to an angle between two straight lines ranging between 90++10°, perpendicular may also refer to a dihedral angle between two planes ranging between 90++10°, and perpendicular may also refer to an angle between a straight line and a plane ranging between 90++10°. The two components described as "perpendicular" may be considered "straight" or "planar" as they are considered "straight" or "planar" in that they are not strictly straight or planar, but may be substantially straight or planar in that they extend in a macroscopic manner.
The term "parallel" is used to describe an ideal state between two components. In an actual production or use state, there may be a state of approximately parallelism between the two components. For example, in connection with numerical descriptions, parallel may refer to an angle between two straight lines ranging between 180++10°, parallel may refer to a dihedral angle between two planes ranging between 180++10°, and parallel may refer to an angle between a straight line and a plane ranging between 180++10°.
The two components described as "parallel" may be considered "straight" or "planar" as they are considered "straight" or "planar" in that they are not strictly straight or planar, but may be substantially straight or planar in that they extend in a macroscopic manner. Due to tolerances in the process, both plane deviations within 0.5mm can be calculated to be parallel.
The technical features mentioned 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.
As shown in fig. 1 to 20, for convenience of description, a three-dimensional rectangular coordinate system is established with a thickness direction of the secondary battery as a first direction X, a width direction of the secondary battery as a second direction Y, and a length direction of the secondary battery as a third direction Z.
In some embodiments, the first direction X is parallel to a direction in which the first main wall 111 and the second main wall 112 are disposed opposite to each other in the package 10 to be described later; in addition, the first direction X is also parallel to a direction in which the respective electrode sheets in the electrode assembly 20, which will be described later, are stacked.
In some embodiments, the second direction Y is parallel to a direction in which the first side wall 1132 and the second side wall 1134 are disposed opposite in the package 10 to be described later; further, the second direction Y is also parallel to a direction from a side of the first top seal portion 12 near the first side seal portion 13 to a side near the second side seal portion 16 in the package bag 10 to be described later.
In some embodiments, the third direction Z is parallel to a direction in which the first top wall 1131 and the bottom wall 1133 are disposed opposite in the package 10 to be described later; in addition, the third direction Z is also parallel to the extending direction of the first tab 30 to be described later.
First embodiment
Fig. 1 is a schematic structural view of a secondary battery according to a first embodiment of the present application, and fig. 5 is a schematic structural view of the secondary battery shown in fig. 1 when an electrode assembly is not mounted in a package bag.
First, referring to fig. 1 and 5 together, the secondary battery includes: the electrode assembly includes a package pouch 10, an electrode assembly 20, a first tab 30, and a second tab 40. The package bag 10 is a receiving base of the electrode assembly 20, which defines a receiving chamber (not shown), and the electrode assembly 20 is received in the receiving chamber. The first tab 30 and the second tab 40 are both located on the same side of the package 10. In the receiving cavity, one end of the first tab 30 and one end of the second tab 40 are electrically connected to the electrode assembly 20. The other end of the first tab 30 and the other end of the second tab 40 extend out of the package bag 10 through the receiving cavity. The first tab 30 and the second tab 40 are configured to be electrically connected with an electric device to realize charge and discharge of the secondary battery.
In some embodiments, the secondary battery includes an electrolyte, which is received in the receiving cavity and wets the electrode assembly 20.
In some embodiments, the secondary battery is a soft-pack lithium ion secondary battery.
Next, a structure of a soft pack secondary battery will be described using a soft pack lithium ion secondary battery as an example. It is to be understood that the secondary battery may be other types of soft pack secondary batteries besides soft pack lithium ion secondary batteries, and soft pack sodium ion secondary batteries, solid state soft pack secondary batteries, semi-solid state soft pack secondary batteries, and the like may be cited as such soft pack secondary batteries.
Fig. 2 is a schematic structural view of another secondary battery according to the first embodiment of the present application, fig. 3 is a partially enlarged view of fig. 1 a, fig. 4 is a partially enlarged view of fig. 1 b, and fig. 10 is a sectional view of fig. 1 taken along the line A-A.
Next, the configuration of the package 10 will be described with reference to fig. 1 to 4, 5 and 8.
Referring to fig. 1 in conjunction with fig. 10, in some embodiments, the package 10 has a substantially flat rectangular parallelepiped shape and includes a main body 11, a first top sealing portion 12, a first side sealing portion 13, and a second side sealing portion 16. The main body 11 includes a first main wall 111, a second main wall 112, and a plurality of side walls 113. The plurality of side walls 113 includes a first top wall 1131, a first side wall 1132, a second side wall 1134, and a bottom wall 1133. The first top wall 1131, the first side wall 1132, the bottom wall 1133 and the second side wall 1134 are sequentially connected end to end and respectively connected to the periphery of the first main wall 111 and the periphery of the second main wall 112, so as to jointly enclose the accommodating cavity. The first main wall 111 and the second main wall 112 are disposed opposite to each other, the first side wall 1132 and the second side wall 1134 are disposed opposite to each other, and the bottom wall 1133 and the first top wall 1131 are disposed opposite to each other. The first top sealing portion 12 is connected to the first top wall 1131 and is bent toward the first direction X. The first side seal 13 is connected to the first side wall 1132 and extends outwardly. The second side seal 16 is connected to the second side wall 1134 and extends outwardly.
It is understood that the shape of the package 10 is not limited to the aforementioned rectangular parallelepiped shape, and can be adaptively adjusted according to actual use requirements. For example, in other embodiments, the package 10 may be L-shaped or regular polyhedral. In addition, the shape of the packing bag 10 is related to the shape of the electrode assembly 20 to be described later, and the shape thereof may vary with the shape of the electrode assembly 20.
As can be seen from fig. 3, in some embodiments, a first gap 14 is formed between the first side seal 13 and the first top seal 12 in the second direction Y. The other end of the first tab 30 protrudes outside the package bag 10 through the receiving cavity and the first gap 14.
Specifically, in the second direction Y, a first gap 14 is formed between a side edge of the first side seal 13 in the third direction Z and a side edge of the first top seal 12 in the second direction Y.
The first tab 30 includes a first metal strip 31 and a first tab adhesive 32 surrounding and wrapping the first metal strip 31. The first tab adhesive 32 is disposed on the package bag 10, and along the third direction Z, a projection of the first tab adhesive 32 falls into the first gap 14. One end of the first metal tape 31 is electrically connected to the electrode assembly 20 in the receiving cavity, and the other end of the first metal tape 31 extends out of the package 10 through the first tab adhesive 32 and the first gap 14 in the third direction Z, and a portion of the first metal tape 31 extending out of the package 10 may be electrically connected to an electric device.
It should be noted that, when it is satisfied that the projection of one side edge of the first top seal 12 in the second direction Y is separated from the projection of one side edge of the first side seal 13 in the third direction Z as viewed in the first direction X, it may be determined that the first gap 14 is formed between the first side seal 13 and the first top seal 12 in the second direction Y. Alternatively, when it is satisfied that the projection of one side edge of the first top seal 12 in the second direction Y is separated from the projection of one side edge of the first side seal 13 in the third direction Z as viewed in the third direction Z, it may be determined that the first gap 14 is formed between the first side seal 13 and the first top seal 12 in the second direction Y.
In the secondary battery according to the present application, the first tab 30 no longer protrudes from the first top seal 12, and thus the first top seal 12 is folded without being affected by the hardness of the first tab adhesive 32. Compared with the scheme that the first tab 30 extends from the first top sealing portion 12 and is bent together with the first tab, the bending resilience force generated by folding the first top sealing portion 12 is small, namely the warping degree of the first top sealing portion 12 is reduced, the occupied space of the first top sealing portion 12 in the third direction Z after being bent is reduced, and the battery capacity of the secondary battery is improved.
As can be seen in fig. 4, in some embodiments, a second gap 15 is formed between the second side seal 16 and the first top seal 12 in the second direction Y. The other end of the second tab 40 extends out of the package 10 through the receiving cavity and the second gap 15.
Specifically, in the second direction Y, a second gap 15 is formed between one side edge of the second side seal 16 in the third direction Z and the other side edge of the first top seal 12 in the second direction Y.
The second tab 40 includes a second metal band 41 and a second tab adhesive 42 surrounding the second metal band 41. The second ear glue 42 is disposed in the package 10, and along the third direction Z, the projection of the second ear glue 42 falls into the second gap 15. One end of the second metal tape 41 is electrically connected to the electrode assembly 20 in the receiving cavity, the other end of the second metal tape 41 protrudes out of the package 10 through the second ear glue 42 and the second gap 15, and a portion of the second metal tape 41 protruding out of the package 10 may be electrically connected to an electric device.
It should be noted that, when the determination condition of the second gap 15 is satisfied, it may be determined that the second gap 15 is formed between the second side seal portion 16 and the first top seal portion 12 along the second direction Y, and since the determination condition of the second gap 15 is similar to the determination condition of the first gap 14, the detailed description will be omitted herein with reference to the related description in the first gap 14.
In the above technical solution, the second tab 40 does not extend from the second top sealing portion 17 any more, so that the second top sealing portion 17 is not affected by the hardness of the second tab adhesive 42 when being folded, compared with the solution that the second tab 40 extends from the first top sealing portion 12 and is folded together with the first top sealing portion 12, the bending resilience force generated by folding the first top sealing portion 12 is smaller, that is, the degree of warpage of the first top sealing portion 12 is reduced, the occupied space in the third direction Z after the first top sealing portion 12 is folded is reduced, so that the head space occupation of the secondary battery is reduced, and the capacity of the secondary battery is further improved.
Of course, the arrangement of the first tab 30 and the second tab 40 can be adaptively adjusted according to the actual use requirement, for example, as shown in fig. 2, in other embodiments, the first tab 30 and the second tab 40 are respectively located on two opposite sides of the package bag 10. The first tab 30 extends from the first gap 14 at the head of the secondary battery, and the second tab 40 extends from the second gap 15 at the tail of the secondary battery, so that the occupation of the head and tail space of the secondary battery can be reduced, and the capacity of the secondary battery can be improved.
For the specific construction of the package 10, it includes a first film 101 and a second film 102. The first membrane 101 and the second membrane 102 may be integrally provided or may be separately provided. For example, as shown in fig. 5, the first membrane 101 and the second membrane 102 may be formed by folding a membrane material in a composite layer structure. In the case of a specific implementation of the method,
first, a first notch 1011 is punched at a first corner of the first film 101, and a second notch 1021 is punched at a position corresponding to the first notch 1011 at the first corner on the second film 102; a third notch 1012 is punched at the second angular position of the first film 101, and a fourth notch 1022 is punched at a position corresponding to the third notch 1012 at the second angular position on the second film 102;
Secondly, at least one pit is formed after at least one of the first membrane 101 and the second membrane 102 is subjected to a pit punching process;
then, folding and coating the electrode assembly 20 along the fold line at the middle part of the membrane;
and then packaging the sealing edges except the part where the punching pit is located, hot-pressing the first corner to enable the first tab adhesive 32, the first diaphragm 101 and the second diaphragm 102 to be formed in a melting mode, and hot-pressing the second corner to enable the second tab adhesive 42, the first diaphragm 101 and the second diaphragm 102 to be formed in a melting mode.
The two edges adjacent to the first notch 1011 are the first top seal 12 and the first side seal 13, and the edge opposite to the first side seal 13 along the second direction Y is the second side seal 16.
The closed space formed by drawing at least one of the first film 101 and the second film 102 by pressing and packaging is the aforementioned accommodation chamber.
The first top sealing portion 12 is bent towards the first direction X, and is used for being partially attached to the first top wall 1131.
One side edge of the first top sealing portion 12 along the second direction Y and one side edge of the first side sealing portion 13 along the third direction Z define a boundary of the first gap 14.
The other side edge of the first top sealing portion 12 along the second direction Y and the one side edge of the second side sealing portion 16 along the third direction Z define the boundary of the second gap 15.
In some embodiments, the composite layer structure includes a first polymer layer, a metal layer, and a second polymer layer, which are sequentially laminated along the interior of the receiving cavity to the exterior of the receiving cavity to form the aforementioned first membrane 101 and/or second membrane 102.
Wherein the first polymer layer melts at a predetermined temperature and is tacky to facilitate packaging of the package 10. As a material for forming such a first polymer layer, polyethylene, polypropylene, polycarbonate, polyamide, polyethylene terephthalate, acrylonitrile-butadiene-styrene copolymer, polyoxymethylene, polyphenylene ether, and the like are exemplified, whereby the first polymer layer is hardly dissolved, swelled, and the like by an electrolyte, thereby reducing the risk of corrosion of a metal layer adjacent to the first polymer layer.
The metal layer serves to reduce the risk of moisture penetrating into the receiving cavity and to improve the structural strength of the package 10. As a material for forming such a metal layer, aluminum foil, austenitic-ferritic duplex stainless steel foil, etc. are exemplified, whereby the metal layer can react with oxygen in the air to form a dense oxide film, thereby reducing the risk of moisture penetrating into the accommodating chamber.
The second polymer layer serves to reduce the risk of air infiltration into the receiving cavity while enhancing the deformability of the package 10. Examples of the material for forming such a second polymer layer include polyamide, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, acrylonitrile-butadiene-styrene copolymer, polyoxymethylene, polyphenylene ether, and the like.
It is to be understood that the packaging manner between the first membrane 101 and the second membrane 102 is not particularly limited in each embodiment of the present application. For example, the first membrane 101 and the second membrane 102 may be fixedly connected by gluing or hot pressing, or may be press-fit and then heat-sealed, or may be fixedly connected by other processes.
It is also understood that the constitution of the package bag 10 is practically diverse, and is not limited to the specific constitution of the package bag 10 as mentioned above, but it is sufficient to be able to serve as a receiving base of the electrode assembly 20 and to have a deformability similar to that of the package bag 10 described above. In addition, the package bag 10 should be configured such that a first gap 14 is formed between one side edge of the first top sealing portion 12 along the second direction Y and one side edge of the folded first side sealing portion 13 along the third direction Z, and the other end of the first tab 30 extends out through the first gap 14.
In some embodiments, the first side seal 13 and/or the second side seal 16 are bent in the first direction X, the first side seal 13 being configured to engage the first side wall 1132, and the second side seal 16 being configured to engage the second side wall 1134. Thereby, the space occupied by the secondary battery inside the power consumption device, which can be used to increase the size of the electrode assembly 20, thereby increasing the energy density of the secondary battery, can be reduced. At this time, the boundary of the first gap 14 may be defined by a side edge of the folded first top sealing portion 12 along the second direction Y and a side edge of the folded first side sealing portion 13 along the third direction Z.
Referring to fig. 10 in conjunction with fig. 3 or 9, in order to improve the contact and short circuit between the first metal strip 31 and the exposed metal layer on the packaging bag 10 disposed around the outer peripheral surface thereof, in some embodiments, along the third direction Z, one end of the first tab adhesive 32 exceeds the edge of the packaging bag 10 on which the first tab adhesive 32 is packaged.
Further, as viewed along the second direction Y, a projection of the first tab adhesive 32 in the third direction Z beyond the first top wall 1131 coincides with a projection of the first top seal 12. The advantage of this setting is that in the distance that first tab gum 32 surpassed the one side edge of encapsulation has first tab gum 32 on wrapping bag 10, the head is because the high restriction of first tab gum 32 has a partial head space extravagant, set up that first top seal portion 12 and first tab gum 32 exist the coincidence along third direction Z in, can better utilize this partial extravagant space, thereby improve the distance of energy density partly and offset by the space size that first top seal portion 12 occupy in third direction Z, thereby secondary cell head space occupation further reduces, and then the capacity of secondary cell can further promote.
Referring to fig. 4 or 8 in conjunction with fig. 10, in order to improve the contact and short circuit between the second metal strip 41 and the exposed metal layer on the packaging bag 10 disposed around the outer peripheral surface thereof, in some embodiments, one end of the second ear glue 42 extends beyond the edge of the packaging bag 10 on which the second ear glue 42 is packaged along the third direction Z.
Further, as viewed in the second direction Y, a projection of the second ear glue 42 in the third direction Z beyond the portion of the package 10 coincides with a projection of the second top seal 17. So configured, in the distance that the second ear glue 42 exceeds the edge of the side of the package bag 10 where the second ear glue 42 is packaged, a part of the distance is offset by the space occupied by the first top sealing portion 12 in the third direction Z, so that the head space occupation of the secondary battery is further reduced, and the capacity of the secondary battery can be further improved.
Fig. 6 is a partial enlarged view of c in the secondary battery shown in fig. 5.
Referring to fig. 5 and 6 together, in some embodiments, the electrode assembly 20 includes a first electrode sheet 21, a second electrode sheet 22 having a polarity different from that of the first electrode sheet 21, and a separator 23 separating the first and second electrode sheets 21 and 22. One of the first and second pole pieces 21 and 22 is electrically connected to the first tab 30, and the other is electrically connected to the second tab 40.
For convenience of description, the first electrode sheet 21 is taken as a positive electrode sheet, and the second electrode sheet 22 is taken as a negative electrode sheet in each of the following embodiments.
The first pole piece 21 includes a first current collector (not shown) and a first active material layer (not shown) coated on at least one surface of the first current collector, and the first current collector is electrically connected to one end of the first tab 30 in the accommodating cavity.
It is to be understood that the electrical connection manner between the first tab 30 and the first current collector is not particularly limited in the embodiments of the present application. For example, in some embodiments, the first tab 30 and the first current collector are different portions on the same component. In a specific implementation, the first tab 30 and the first current collector matched with the shape of the main body 11 may be die-cut on a complete metal foil, and then at least one surface of the first current collector is coated with a first active material layer to form the first pole piece 21. For another example, in other embodiments, the first tab 30 and the first current collector are separate components. In particular, the first current collector coated with the first active material layer may be scraped with a groove exposed on the surface of the first current collector, and then the first tab 30 may be fixed on the surface of the first current collector in the groove by, but not limited to, laser welding.
The first current collector includes, but is not limited to, one or more of an aluminum mesh, aluminum foil, copper foil, etc., conductive metal sheets. As an example, the first current collector is made of aluminum foil.
The first active material layer includes, but is not limited to, one or more of lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium manganate, lithium nickelate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium iron phosphate, and lithium rich manganese based materials.
The second tab 22 includes a second current collector electrically connected to the second tab 40 at an end thereof extending into the receiving cavity, and a second active material layer (not shown) coated on at least one surface of the second current collector (not shown).
The second current collector includes, but is not limited to, one or both of a copper foil, a nickel foil, and the like, conductive metal sheets. As an example, the second current collector is made of copper foil.
The second active material layer includes, but is not limited to, one or more of artificial graphite, natural graphite, soft carbon, hard carbon, graphene, mesophase carbon microspheres, silicon-based materials, tin-based materials, lithium carbonate, or other metals capable of forming alloys with lithium.
It is to be understood that the electrical connection between the second tab 40 and the second current collector is not particularly limited in the embodiments of the present application. Since the connection manner between the second tab 40 and the second current collector is similar to the connection manner between the first tab 30 and the first current collector, please refer to the description about the connection manner between the first tab 30 and the first current collector, and the description is omitted herein.
As shown in fig. 5 and 6, in some embodiments, the electrode assembly 20 may be a lamination stack. Specifically, the number of the first pole pieces 21 is at least two, the number of the second pole pieces 22 is also at least two, at least two first pole pieces 21 and at least two second pole pieces 22 are alternately laminated along the first direction X, and the first pole pieces 21 and the second pole pieces 22 are separated by the separation film 23.
In some embodiments, the electrical connection of the plurality of first pole pieces 21 to the first tab 30 and the first gap 14 are disposed opposite in the third direction Z.
In some embodiments, the electrical connections of the plurality of second pole pieces 22 to the second pole ears 40 and the second gap 15 are disposed opposite in the third direction Z.
Alternatively, the electrode assembly 20 may be a wound structure. Specifically, the number of the first pole piece 21 and the second pole piece 22 is one, and the first pole piece 21 and the second pole piece 22 are each in a belt-shaped structure. The first pole piece 21, the separator 23, and the second pole piece 22 are sequentially laminated and wound two or more times.
Of course, the electrode assembly 20 may be a member other than a laminated structure or a wound structure, and may be capable of achieving a secondary battery charge/discharge function.
Second embodiment
For ease of description, the same numbers are used throughout this application to identify elements of the same name. On the basis of the foregoing description of the first embodiment, but unlike it, as shown in fig. 12 or 13, in some embodiments, the package bag 10 has a first space S1, the first space S1 being in communication with a first gap (not shown).
Specifically, the main body 11 includes a second top wall 1135, and the second top wall 1135 includes a first connecting wall 11351 and a second connecting wall 11352. The second connecting wall 11352 and the first top wall 1131 are both located on the same side of the main body 11, the second connecting wall 11352 is connected to the first top wall 1131 through the first connecting wall 11351 and is recessed in a direction opposite to the third direction Z with respect to the first top wall 1131, and the first connecting wall 11351 and the second connecting wall 11352 enclose the first space S1 communicating with the first gap 14. It should be noted here that, as long as there is an uneven area of the component of the second top wall 1135 in the third direction Z, the second top wall 1135 may be considered to be recessed toward the third direction Z with respect to the first top wall 1131. The joint of the first tab 30 and the electrode assembly 20 can be closer to the center of the packaging bag 10, and the space occupied by the switching of the first tab 30 can be reduced.
The first tab adhesive 32 is disposed on the second connecting wall 11352, and an end of the first tab adhesive 32 along the third direction Z extends beyond the second connecting wall 11352 to the first space S1.
The other end of the first metal tape 31 sequentially passes through the receiving cavity, the first tab adhesive 32, the first space S1, and the first gap in the third direction Z to protrude out of the package bag 10.
In the secondary battery according to the present application, the distance of the first tab adhesive 32 beyond the second connection wall 11352 may be contained in the first space S1, or the distance of the first tab adhesive 32 beyond the second connection wall 11352 may be contained in the space enclosed by the first space S1 and the first top sealing part 12 together, so that the head space occupation of the secondary battery is further reduced, and the capacity of the secondary battery may be further improved.
In some embodiments, the second connecting wall 11352 and the first top wall 1131 are disposed parallel to the first direction X, thereby facilitating subsequent packaging of the package 10 and the first tab 30.
In some embodiments, the junction of the first top wall 1131 and the first connecting wall 11351 is rounded to smooth the transition of the first top wall 1131 and the first connecting wall 11351.
In some embodiments, the junction of the first connecting wall 11351 and the second connecting wall 11352 is rounded to smooth the transition of the first connecting wall 11351 and the second connecting wall 11352.
In some embodiments, the junction of the second connecting wall 11352 and the first side wall 1132 is rounded to smooth the transition of the second connecting wall 11352 and the first side wall 1132.
It is understood that the specific shape of the first space S1 is not limited in the embodiments of the present application. For example, as shown in fig. 12 or 13, in some embodiments, the first space S1 is generally rectangular in cross-sectional shape as a whole, viewed along the first direction X. For another example, in other embodiments, the second top wall 1135 is substantially inclined as viewed along the first direction X, and has one end connected to the first top wall 1131 and one end connected to the first side wall 1132. At this time, the first space S1 defined by the first top wall 1131, the second top wall 1135 and the first side wall 1132 may have a triangular shape or other shapes.
As further shown in fig. 12, in some embodiments, the package 10 has a second space S2, the second space S2 being in communication with a second gap (not shown). Specifically, the third top wall 1136 includes a third connecting wall 11361 and a fourth connecting wall 11362. The fourth connecting wall 11362 and the first top wall 1131 are both located on the same side of the main body 11, the fourth connecting wall 11362 is connected with the first top wall 1131 through the third connecting wall 11361 and is recessed towards the third direction Z relative to the first top wall 1131, and the third connecting wall 11361 and the fourth connecting wall 11362 enclose the second space S2 communicated with the second gap. It should be noted that, as long as the component of the third top wall 1136 in the third direction Z has an uneven area, the second top wall 1136 may be considered to be recessed in the third direction Z relative to the first top wall 1131, so that the connection between the second tab 42 and the electrode assembly 20 can be located closer to the center of the packaging bag 10, and the space occupied by the transfer of the second tab 42 can be reduced.
The second ear glue 42 is disposed on the fourth connecting wall 11362, and an end of the second ear glue 42 along the third direction Z extends beyond the fourth connecting wall 11362 to the second space S2.
The other end of the second metal strip 41 sequentially passes through the second ear glue 42, the second space S2 and the second gap 15 to protrude out of the package bag 10 along the third direction Z.
The advantage of this solution is that the distance of the second ear glue 42 beyond the fourth connecting wall 11362 can be accommodated in the second space S2, or the distance of the second ear glue 42 beyond the fourth connecting wall 11362 can be accommodated in the space enclosed by the second space S2 and the first top sealing portion 12 together, and the space dimensions occupied in the third direction Z are offset together, so that the head space occupation of the secondary battery is further reduced, and the capacity of the secondary battery can be further improved.
In some embodiments, the fourth connecting wall 11362 and the first top wall 1131 are disposed in parallel with each other in the first direction X, thereby facilitating subsequent packaging of the pouch and the second tab.
In some embodiments, the junction of the first top wall 1131 and the third connecting wall 11361 is rounded to smooth the transition of the first top wall 1131 and the third connecting wall 11361.
In some embodiments, the junction of the third connecting wall 11361 and the fourth connecting wall 11362 is rounded to smooth the transition of the third connecting wall 11361 and the fourth connecting wall 11362.
In some embodiments, the junction of the fourth connecting wall 11362 and the second side wall 1134 is rounded to smooth the transition of the fourth connecting wall 11362 and the second side wall 1134.
It is understood that the specific shape of the second space S2 is not limited in the embodiments of the present application. For example, as shown in fig. 12, in some embodiments, the second space S2 has a generally rectangular overall cross-sectional shape as viewed along the first direction X. For another example, in other embodiments, the third top wall 1136 is substantially inclined as viewed along the first direction X, and has one end connected to the first top wall 1131 and one end connected to the second side wall 1134. At this time, the second space S2 defined by the first top wall 1131, the third top wall 1136 and the second side wall 1134 may have a triangular shape or other shapes.
Third embodiment
For ease of description, the same numbers are used throughout this application to identify elements of the same name. Based on the foregoing description of the first embodiment, but different therefrom,
as shown in fig. 14, 15, or 20, in some embodiments, the package 10 has a first groove 191, the first groove 191 being in communication with a first gap (not shown).
Specifically, the second top wall 1135 includes a first connecting wall 11351 and a second connecting wall 11352. The second connecting wall 11352 and the first top wall 1131 are both located on the same side of the main body 11, and the second connecting wall 11352 is connected to the first top wall 1131 through the first connecting wall 11351 and is recessed in the third direction Z relative to the first top wall 1131.
The package 10 includes a second top seal 17, the second top seal 17 being connected to the second connecting wall 11352 and extending outwardly therefrom, the second top seal 17 being connected to the first top seal 12 and the first side seal 13, respectively. Wherein the first connecting wall 1135, the second top sealing portion 17 and the second connecting wall 11352 together enclose the first groove 191.
The first tab adhesive 32 is disposed on the second top sealing portion 17, and one end of the first tab adhesive 32 along the third direction Z extends beyond an edge of one side of the second top sealing portion 17 to the first gap.
The other end of the first metal tape 31 sequentially passes through the accommodating chamber, the first tab adhesive 32, and the first gap in the third direction Z to protrude out of the package bag 10.
In the secondary battery according to the present application, the presence of the second top seal 17 allows a large contact area between the first tab adhesive 32 and the package bag 10, so that stable connection reliability between the first tab adhesive 32 and the second seal is maintained, and leakage between the first metal tape 31 and the second top seal 17 can be improved. The first groove 191 is positioned at a corner of the body portion 11, and can facilitate the fixing and positioning of the first tab 30 by the hot pressing jig to improve the assembly efficiency of the secondary battery.
It is understood that the specific shape of the first groove 191 is not limited in the embodiments of the present application. For example, as shown in fig. 14-16 or 20, in some embodiments, the first slot 191 has a generally rectangular overall cross-sectional shape as viewed in the first direction X. For example, in other embodiments, the second top wall 1135 is inclined, and connects the first top wall 1131 and the first side wall 1132, and the first groove 191 is surrounded by the second top wall 1135, the second top sealing portion 17, and the first side wall 1132, where the first groove 191 may be a trapezoid groove or other shapes.
In some embodiments, the second connecting wall 11352 and the first top wall 1131 are disposed in parallel with each other in the first direction X, so that subsequent packaging of the pouch and the first tab may be facilitated.
As shown in fig. 14, in some embodiments, the second connecting wall 11351 is spaced apart from the folded first top seal 12 along the third direction Z by a spacing S 1 The second top sealing part 17 extends out of the second connecting wall 11351 and is adhered with the first tab32 sum of distances S beyond the second top seal 17 2 ，S 1 And S is 2 The method meets the following conditions: s is S 1 ≥S 2 . In this way, the first tab adhesive 32 does not need to be bent under the premise of less influence on the volumetric energy density of the secondary battery, so that the situation that the connection strength around the first tab adhesive 32 is insufficient and liquid leaks caused by bending the first tab adhesive 32 can be improved.
As shown in fig. 14-16 or fig. 20, in some embodiments, a side edge of the second top sealing portion 17 away from the second connecting wall 1136 is flush with a side edge of the first side sealing portion 13 along the third direction Z, so that the processing procedure of the packaging bag 10 can be reduced, and the production efficiency of the secondary battery can be improved. It should be noted that reference herein to phase being flush is not intended to be strictly flush, and should be considered flush to within 0.5mm due to process tolerances.
As shown in fig. 14, 15, 17, or 20, in some embodiments, the package 10 has a second slot 192, the second slot 192 being in communication with a second gap (not shown).
Specifically, the third top wall 1136 includes a third connecting wall 11361 and a fourth connecting wall 11362. The fourth connection wall 11362 and the first top wall 1131 are both located on the same side of the main body 11, and the fourth connection wall 11362 is connected to the first top wall 1131 through the third connection wall 11361 and is recessed in a direction opposite to the third direction Z with respect to the first top wall 1131.
The package 10 includes a third top seal 18, the third top seal 18 being connected to the fourth connecting wall 11362 and extending out of the receiving cavity, the third top seal 18 being connected to the first top seal 12 and the second side seal 16, respectively. Wherein the third connecting wall 11361, the third top sealing portion 18 and the fourth connecting wall 11362 together enclose the second groove 192.
The second ear glue 42 is disposed on the third top sealing portion 18, and one end of the second ear glue 42 in the third direction Z extends beyond an edge of one side of the third top sealing portion 18 to the second gap 15.
The other end of the second metal strip 41 sequentially passes through the receiving chamber, the second ear glue 42, and the second gap 15 in the third direction Z to protrude out of the package bag 10.
In the secondary battery according to the present application, the presence of the third top seal 18 allows a large contact area between the second electrode adhesive 42 and the package bag 10, so that stable connection reliability between the second electrode adhesive 42 and the third top seal 18 is maintained, and leakage between the second metal tape 41 and the third top seal 18 can be improved. The second groove 192 is positioned at another angular position of the main body 11, which facilitates the fixing and positioning of the second tab 40 by the hot press jig to improve the assembly efficiency of the secondary battery.
It is to be understood that the specific shape of the second groove 192 is not limited by the embodiments of the present application. For example, as shown in fig. 11, 12, or 14, in some embodiments, the second slot 192 has a generally rectangular overall cross-sectional shape as viewed along the first direction X. For example, in other embodiments, the third top wall 1135 connects the first top wall 1131 and the second side wall 1134, and the third top wall 1135, the third top seal 18, and the second side wall 1134 together define the second groove 192, where the first groove 192 may be a trapezoid groove or other shape.
In some embodiments, the fourth connecting wall 11362 and the first top wall 1131 are disposed in parallel with each other in the first direction X, thereby facilitating subsequent packaging of the pouch and the second tab.
As shown in fig. 14, in some embodiments, the fourth connecting wall 11362 is spaced apart from the folded first top seal 12 along the third direction Z by a spacing S 3 The sum S of the distance that the third top sealing portion 18 extends beyond the fourth connecting wall 11362 and the distance that the second ear adhesive 42 portion of one side edge of the third top sealing portion 18 in the third direction Z extends 4 ，S 3 And S is 4 The method meets the following conditions: s is S 3 ≥S 4 . In this way, the second electrode adhesive 42 does not need to be bent under the premise of less influence on the volumetric energy density of the secondary battery, so that the situation that the connection strength around the second electrode adhesive 42 is insufficient and liquid leakage occurs due to bending of the second electrode adhesive 42 can be improved.
As shown in fig. 14 or 20, in some embodiments, a side edge of the third top sealing portion 18 away from the fourth connecting wall 11362 is flush with a side edge of the second side sealing portion 16 along the third direction Z, which is not strictly flush, and should be flush within 0.5mm due to process tolerance, so that the processing procedure of the packaging bag 10 can be reduced, and the production efficiency of the secondary battery can be improved.
Referring also to fig. 18-20, in some embodiments, the receiving cavity includes a first cavity (not shown) and a second cavity (not shown) in communication with the first cavity. The first cavity may be defined by the second connecting wall 11352, the first side wall 1132, the bottom wall 1133, the second side wall 1134, the fourth connecting wall 11362, and a virtual connection line between the fourth connecting wall 11362 and the second connecting wall 11352. The second cavity may be defined by the first top wall 1131, the first connecting wall 1135, the virtual connection line between the fourth connecting wall 11362 and the second connecting wall 11352, and the third connecting wall 11361.
The electrode assembly 20 includes an electrode assembly main body 201 and a protrusion 202 integrally connected with the electrode assembly main body 201, the electrode assembly 20 is accommodated in the first cavity, and the protrusion 202 is accommodated in the second cavity. Specifically, any one of the first pole pieces 21 includes a first pole piece body (not shown) and a first protruding portion (not shown) integrally connected with the first pole piece body, any one of the second pole pieces 22 includes a second pole piece body (not shown) and a second protruding portion (not shown) integrally connected with the second pole piece body, and any one of the separator films 23 includes a separator film body (not shown) and a third protruding portion (not shown) integrally connected with the separator film body. The electrode assembly body 201 may be formed of at least two first electrode sheet bodies, at least two separator film bodies, and at least two second electrode sheet bodies alternately stacked in sequence along the first direction X. The convex portion 202 may be formed by alternately stacking at least a first convex portion, at least a third convex portion, and at least two second convex portions in sequence along the first direction X.
It should be noted here that the first pole piece body and the first protrusion differ in location and the remaining construction is substantially the same, i.e. the first pole piece body and the first protrusion each comprise a first current collector and a first active material layer. The second pole piece body and the second protruding portion are also different in position and the rest of the construction is substantially the same, i.e. the second pole piece body and the second protruding portion each comprise a second current collector and a second active material layer. The separator body and the third protrusion differ in location and the remaining construction is substantially identical.
In the first cavity, the electrode assembly main body 201 is electrically connected to one end of the first tab 30 and one end of the second tab 40, respectively. Specifically, a plurality of first tab bodies are electrically connected to one end of the first tab 30, and a plurality of second tab bodies are electrically connected to one end of the second tab 40.
As shown in fig. 12, in some embodiments, a plurality of first pole piece bodies are disposed opposite the electrical connection of the first tab 30 and the second connection wall 11352 along the third direction Z. In other words, the electrical connection between the plurality of first pole piece bodies and the first tab 30 may no longer be disposed in a partial region of the second cavity opposite the first top seal 12. On the one hand, the gap between the convex portion 202 and the first top seal 12 is shortened, so that the amount of free electrolyte accumulation in this partial region can be reduced, thereby improving the occurrence of shorting due to shrinkage of the separator film 23 where the amount of free electrolyte accumulation is excessive, which impacts the convex portion 202. On the other hand, the first top seal portion 12 is not affected by the first metal tape 31 and the first tab adhesive 32 any more at the time of heat sealing, and the first top seal portion 12 has stable connection strength after heat sealing. On the other hand, the size of the first top sealing part 12 extending outward is also reduced by being not affected by the first metal tape 31 and the first tab adhesive 32, whereby the volumetric energy density of the secondary battery is further improved.
As further shown in fig. 17, in some embodiments, the electrical connections of the plurality of second pole piece bodies to the second pole ears 40 and the fourth connecting wall 11362 are disposed opposite in a third direction Z. Based on the similar mechanism as described in the electrical connection of the first pole piece body and the first tab 30, the same effects as in the previous embodiments are also achieved, and will not be described in detail here. In addition, when the first tab 30 and the second tab 40 are respectively located at two opposite sides of the first top sealing portion 12 along the second direction Y, even if the presence of the first space S1 and the second space S2 reduces the capacity of the secondary battery, the increased capacity of the protruding portion 202 is still greater than the sum of the reduced capacities of the two, i.e., the total capacity of the secondary battery can still be increased, compared to the same-sized folded top sealing battery. It should be noted that the plural references herein specifically refer to two and more.
In some embodiments, as shown in fig. 19, in the third direction, the ends of the plurality of third protruding portions beyond the second protruding portions are connected and fixed to form a connecting portion (not shown), and may be fixed by hot pressing. Thus, the integral structure formed by connecting and fixing the plurality of third protruding parts can raise the upper limit of the maximum impact stress, so that the situation that the isolating film 23 of the free electrolyte impacts the isolating film 202 is folded and shorted is improved.
In the traditional battery cell, because the positive and negative lugs all stretch out from the middle of the electrode assembly, the connecting part can not be longer in the second direction Y because of the interference of the lugs, and the failure rate of the connecting part is higher, so that the situation of shrinkage of the isolating film occurs. The inventors of the present application have experimentally demonstrated that this type of secondary battery has a superior failure rate in a drop test by limiting the length of the connecting portion in the second direction Y to 15mm to 120 mm.
Further, the length of the connecting portion in the second direction is 20mm to 120mm, so that the connecting strength of the connecting portion is further increased.
As shown in fig. 12-15, in some embodiments, one side edge of the first top seal 12 in the second direction Y extends beyond the first top wall 1131. Thus, the first top sealing portion 12 can be kept at a certain safety distance at the position connected with the first connecting wall 1135, so that the first top sealing portion 12 can be reliably sealed at the position connected with the first connecting wall 1135, and breakage and leakage of liquid at the position can be reduced.
Similarly, the other side edge of the first top sealing portion 12 along the second direction Y extends beyond the first top wall 1131.
Still another embodiment of the present application provides an electric device including any one of the secondary batteries as described above. The power device of the present application may be, but is not limited to, a notebook computer, a pen-input computer, a mobile computer, an electronic book player, a portable telephone, a portable facsimile machine, a portable copier, a portable printer, a headset, a video recorder, a liquid crystal television, a portable cleaner, a portable CD machine, a mini-compact disc, a transceiver, an electronic notepad, a calculator, a memory card, a portable audio recorder, a radio, a standby power supply, a motor, an automobile, a motorcycle, a power assisted bicycle, a lighting fixture, a toy, a game machine, a clock, an electric tool, a flash lamp, a camera, a household large-sized battery, a lithium ion capacitor, and the like.
The foregoing description is only exemplary embodiments of the present application and is not intended to limit the scope of the present application, and all equivalent structures or equivalent processes using the descriptions and the drawings of the present application, or direct or indirect application in other related technical fields are included in the scope of the present application.

Claims (15)

1. The secondary battery comprises a packaging bag, an electrode assembly and a first tab, wherein the packaging bag comprises a main body part, a first top sealing part and a first side sealing part, the electrode assembly is arranged in the main body part, the main body part comprises a first top wall and a first side wall, the first top sealing part is connected with the first top wall and bends towards a first direction, the first side wall is positioned at one side of the first top wall along a second direction, the first side sealing part is connected with the first side wall, wherein the first direction is perpendicular to the second direction,
a first gap is formed between the first side sealing part and the first top sealing part along the second direction;
the first tab includes a first metal strip and surrounds the first tab adhesive arranged on the first metal strip, one end of the first metal strip is electrically connected with the electrode assembly, the first tab adhesive is adhered to the packaging bag, and the other end of the first tab penetrates through the first tab adhesive and the first gap to extend out of the packaging bag.
2. The secondary battery according to claim 1, wherein the main body portion includes a second top wall that connects the first top wall and the first side wall, respectively, and that is recessed toward a third direction with respect to the first top wall, wherein the third direction, the second direction, and the first direction are perpendicular to each other;
the packaging bag comprises a second top sealing part, wherein the second top sealing part is arranged on the second top wall, and the second top sealing part is connected with the first top sealing part and the first side sealing part;
the other end of the first metal strip extends out of the packaging bag through the second top sealing part and the first gap.
3. The secondary battery according to claim 2, wherein the second top wall includes a first connection wall and a second connection wall, the second connection wall being connected to the first top wall through the first connection wall;
the second connecting wall and the first top wall are arranged in parallel with respect to the first direction.
4. The secondary battery according to claim 3, wherein the first tab adhesive is provided at the second top sealing portion, and one end of the first tab adhesive exceeds one side edge of the second top sealing portion in the third direction;
And when the first tab adhesive is observed along the second direction, the projection of the first tab adhesive beyond the edge part of one side of the second top sealing part coincides with the projection of the first top sealing part.
5. The secondary battery according to claim 4, wherein the second connection wall is spaced apart from the first top seal by a distance S between the surface facing away from the first top wall in the third direction 1 Along the third direction, the sum S of the distance between the end of the second top sealing part, which is close to the second connecting wall, and the end, which is far away from the second connecting wall, and the distance between the first tab adhesive and the edge part of the side, which is beyond the second top sealing part, is 2 ，S 1 And S is 2 The method meets the following conditions: s is S 1 ≥S 2 。
6. The secondary battery according to any one of claims 2 to 5, wherein the package bag includes a second side seal portion, the main body portion includes a second side wall, the second side wall is located on the other side of the first top wall in the second direction, and the second side seal portion is connected to the second side wall;
a second gap is formed between the second side seal part and the first top seal part along the first direction;
the secondary battery comprises a second tab, the second tab comprises a second metal strap and second tab adhesive wrapping the second metal strap in a surrounding mode, one end of the first metal strap is electrically connected with the electrode assembly, and the other end of the second tab penetrates through the second tab adhesive and the second gap to extend out of the packaging bag.
7. The secondary battery according to claim 6, wherein the main body portion includes a third top wall that connects the first top wall and the second side wall, respectively, and that is recessed in a third direction with respect to the first top wall, wherein the third direction, the second direction, and the first direction are perpendicular to each other;
the packaging bag comprises a third top sealing part which is arranged on the third top wall and is connected with the first top sealing part and the second side sealing part;
the other end of the second metal strip extends out of the packaging bag through the third top sealing part and the second gap.
8. The secondary battery according to claim 7, wherein the third top wall includes a third connection wall and a fourth connection wall, the fourth connection wall being connected to the first top wall through the third connection wall;
the fourth connecting wall and the first top wall are disposed in parallel with respect to the first direction.
9. The secondary battery according to claim 8, wherein the second electrode tab is provided on the third top sealing portion, and one end of the second electrode tab exceeds one side edge of the third top sealing portion in the third direction;
Viewed along the second direction, the projection of the second ear glue beyond the edge part of one side of the third top sealing part is overlapped with the projection of the first top sealing part.
10. The secondary battery according to claim 9, wherein the package bag has a first cavity and a second cavity communicating with the first cavity;
the electrode assembly comprises an electrode assembly main body and a convex part integrally connected with the electrode assembly main body, wherein the electrode assembly main body is accommodated in the first cavity, and the convex part is accommodated in the second cavity;
one end of the first metal strip and one end of the second metal strip are electrically connected with the electrode assembly body;
the electrode assembly includes a first electrode sheet, a second electrode sheet, and a separator separating the first electrode sheet and the second electrode sheet;
the first pole piece comprises a first pole piece main body and a first protruding part integrally connected with the first pole piece main body;
the second pole piece comprises a second pole piece main body and a second protruding part integrally connected with the second pole piece main body;
the isolating membrane comprises an isolating membrane main body and a third protruding part which is integrally connected with the isolating membrane main body;
The electrode assembly main body is formed by alternately stacking the first pole piece main body, the isolating film main body and the second pole piece main body in sequence, and the convex part is formed by alternately stacking the first convex part, the third convex part and the second convex part in sequence.
11. The secondary battery according to claim 10, wherein a junction of the electrode assembly main body and the first metal strip is disposed opposite to the second top wall in the third direction; and/or
Along the third direction, the connection part of the electrode assembly main body and the second metal belt is opposite to the third top wall.
12. The secondary battery according to claim 10, wherein the number of the third protrusions is at least two, along
And along the third direction, the end parts of at least two third protruding parts exceeding the second protruding parts are mutually connected and fixed to form a connecting part.
13. The secondary battery according to claim 12, wherein a length of the connection portion in the second direction is 15mm to 120mm.
14. The secondary battery according to any one of claims 9 to 13, wherein the second side seal is folded toward the first direction; and/or
The first side seal is bent towards the first direction.
15. An electric device comprising the secondary battery according to any one of claims 1 to 14.
CN202410140070.0A 2024-02-01 2024-02-01 Secondary battery and electricity utilization device Pending CN117790874A (en)

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CN207781658U (en) * 2017-12-28 2018-08-28 北京小米移动软件有限公司 Soft-package battery and electronic equipment
CN207781720U (en) * 2018-01-17 2018-08-28 东莞市黄城河电子科技有限公司 A kind of novel lug
CN112086585A (en) * 2019-06-14 2020-12-15 东莞新能德科技有限公司 Battery with a battery cell
CN112803125A (en) * 2021-02-01 2021-05-14 广州鹏辉能源科技股份有限公司 Tab, soft-package button type lithium ion battery and manufacturing method thereof

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040234848A1 (en) * 2003-05-22 2004-11-25 Samsung Sdi Co., Ltd. Pouch-type lithium secondary battery and fabrication method thereof
CN202259569U (en) * 2011-10-28 2012-05-30 宁德新能源科技有限公司 Lithium secondary battery
CN203205465U (en) * 2012-12-21 2013-09-18 惠州比亚迪电池有限公司 Polymer battery and flexible packaging film for polymer battery
CN207781658U (en) * 2017-12-28 2018-08-28 北京小米移动软件有限公司 Soft-package battery and electronic equipment
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