Secondary battery and battery pack

Abstract

The invention discloses a secondary battery and a battery pack, and belongs to the technical field of batteries. The secondary battery comprises a shell, an electrode assembly, a cover plate assembly and a partition plate, the shell is provided with an accommodating cavity and an opening which are communicated; the electrode assembly is arranged in the accommodating cavity and comprises a body and a tab which are connected with each other; the cover plate assembly is connected with the shell and covers the opening, and the cover plate assembly comprises a pole; the partition plate is arranged in the containing cavity, at least part of the partition plate is located between the body and the cover plate assembly, a through hole is formed in the partition plate, and the tab penetrates through the through hole and is electrically connected with the pole; in the first direction, the through hole has a first size e mm, the tab has a second size s mm, in the second direction, the through hole has a third size f mm, the tab has a fourth size c mm, and e / s is larger than or equal to 1.2 and smaller than or equal to 2; f / c is greater than or equal to 1.2 and less than or equal to 2. The partition plate is arranged, and the through hole for the tab to penetrate through is formed in the partition plate, so that the connection reliability of the tab and the pole is improved.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to a secondary battery and a battery pack. Background Art

[0002] In the conventional production process of new energy power batteries, a soft film is usually used to cover the entire electrode assembly from the bottom to the top cover before the electrode assembly is assembled with the metal shell. After the battery is assembled, the pole ears of the electrode assembly may crack and fold, which may easily cause battery damage and lead to safety hazards such as short circuits. Summary of the invention

[0003] Purpose of the invention: An embodiment of the present application provides a secondary battery, aiming to overcome the current technical problem that the entire soft film covering the electrode assembly easily causes battery damage; another purpose of the embodiment of the present application is to provide a battery pack.

[0004] Technical solution: A secondary battery disclosed in the embodiment of the present application includes:

[0005] A housing having a communicating accommodation cavity and an opening;

[0006] An electrode assembly, the electrode assembly is arranged in the accommodating cavity, and the electrode assembly comprises a body and a pole ear connected to each other;

[0007] A cover plate assembly, the cover plate assembly is connected to the housing and covers the opening, and the cover plate assembly includes a pole;

[0008] A partition, the partition is arranged in the accommodating cavity and at least partially located between the body and the cover assembly, the partition is provided with a through hole, the pole ear passes through the through hole and is electrically connected to the pole;

[0009] The partition has a first direction and a second direction intersecting each other. Along the first direction, the through hole has a first size e mm, and the tab has a second size s mm. Along the second direction, the through hole has a third size f mm, and the tab has a fourth size c mm, satisfying:

[0010] 1.2≤e / s≤2;

[0011] And it satisfies: 1.2≤f / c≤2.

[0012] In some embodiments, the pole ear includes a first connecting section and a second connecting section, the first connecting section is connected to the main body and passes through the through hole; the second connecting section is located on the side of the partition facing away from the main body, and is connected to the end of the first connecting section away from the main body, the second connecting section extends toward the first direction, and is clamped between the partition and the pole, and is electrically connected to the pole.

[0013] In some embodiments, an adhesive layer is further provided on a side of the partition plate facing the cover plate assembly, and the tab passes through the through hole and is connected to the adhesive layer.

[0014] In some embodiments, the pole ear has a weld mark area formed by welding with the pole, the partition has a third direction, the first direction, the second direction and the third direction intersect each other, and along the third direction, the adhesive layer covers the weld mark area.

[0015] In some embodiments, the secondary battery further comprises:

[0016] An insulating film is disposed in the accommodating cavity and covers the body. The insulating film is at least partially disposed on both sides of the partition along the first direction and connected to the partition.

[0017] In some embodiments, along the first direction, the through hole and the insulating film have a distance d mm, the body has a fifth size z mm, and the following is satisfied: 0≤d / z≤0.3.

[0018] In some embodiments, the cover plate assembly is further provided with an explosion-proof valve and a liquid injection hole, and a first hole and a second hole are opened on the partition plate, the first hole is arranged corresponding to the explosion-proof valve, and the second hole is arranged corresponding to the liquid injection hole.

[0019] In some embodiments, the partition has a third direction, the first direction, the second direction and the third direction intersect each other, and along the third direction, the orthographic projection of the pole on the partition is located outside the through hole.

[0020] In some embodiments, the partition has a third direction, the first direction, the second direction and the third direction intersect each other, and along the third direction, the partition has a sixth dimension h mm, satisfying: 0.5≤h≤3.

[0021] The embodiment of the present application also discloses a battery pack, comprising the secondary battery as described in the above embodiment.

[0022] Beneficial effects: The secondary battery provided in the embodiment of the present application includes: a shell, an electrode assembly, a cover assembly and a partition; the shell has a connected accommodating cavity and an opening; the electrode assembly is arranged in the accommodating cavity, and the electrode assembly includes a main body and a pole ear connected to each other; the cover assembly is connected to the shell and covers the opening, and the cover assembly includes a pole; the partition is arranged in the accommodating cavity, and is at least partially located between the main body and the cover assembly, the partition is provided with a through hole, the pole ear passes through the through hole and is connected to the pole; the partition has a first direction and a second direction intersecting each other, along the first direction, the through hole has a first size e mm, the pole ear has a second size s mm, along the second direction, the through hole has a third size f mm, the pole ear has a fourth size c mm, satisfying: 1.2≤e / s≤2; and satisfying: 1.2≤f / c≤2. A partition is provided to separate the main body from the cover assembly, and a through hole is provided on the partition for the pole ear to pass through. On the one hand, the partition can prevent the pole ear from being inserted into the main body after being folded or the folded part from breaking, causing a battery short circuit; on the other hand, the partition can fix and shape the pole ear, avoiding the pole ear from being loosely bonded, the pole ear being inserted outward and contacting with the metal shell, causing a battery short circuit.

[0023] The battery pack of the embodiment of the present application includes the secondary battery as described in the above embodiment, and thus can have all the technical features and technical effects of the above secondary battery, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 This is a schematic diagram of the explosion structure of the secondary battery of the present application;

[0026] Figure 2 A schematic diagram of the positional relationship between the separator and the electrode assembly in the secondary battery of the present application;

[0027] Figure 3 A schematic diagram of the top view of the structure of the separator and the electrode assembly in the secondary battery of this application

[0028] Figure 4 It is a cross-sectional schematic diagram in the AA direction before two electrode assemblies in the secondary battery of the present application are joined together;

[0029] Figure 5 for Figure 4 A partial enlarged schematic diagram of point B in the middle;

[0030] Figure 6It is a cross-sectional schematic diagram in the AA direction after two electrode assemblies in the secondary battery of the present application are combined;

[0031] Figure 7 for Figure 6 A partial enlarged schematic diagram of point C in the middle;

[0032] Figure 8 This is a schematic diagram of the connection structure between the separator and the insulating film in the secondary battery of the present application;

[0033] Figure numerals: 10, shell; 20, electrode assembly; 30, cover plate assembly; 40, partition; 50, insulating film; 60, explosion-proof valve; 101, accommodating chamber; 102, opening; 201, body; 202, pole ear; 301, pole column; 302, injection hole; 401, through hole; 402, adhesive layer; 403, first hole; 404, second hole; 2021, first connecting section; 2022, second connecting section; 2023, welding area; X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0035] In the description of the present application, it should be understood that the terms "first" and "second" are merely used to name parts or embodiments for the convenience of description, and do not imply an order of importance between the parts or embodiments.

[0036] It should also be noted that in the drawings of the present specification, the arrow marked with X indicates the first direction, the arrow marked with Y indicates the second direction, and the arrow marked with Z indicates the third direction. In the description of the present application, the first direction, the second direction, and the third direction are introduced to more clearly define the structure and relative position relationship of each component in the secondary battery. The first direction, the second direction, and the third direction intersect with each other. In actual implementation, the third direction is the height direction of the secondary battery in this embodiment, wherein the first direction is parallel to the short side direction of the cover plate assembly in this embodiment, and the second direction is parallel to the long side direction of the cover plate assembly in this embodiment.

[0037] As a preface to the embodiments of the present application, in the current mainstream production process of new energy power batteries, the manufactured electrode assembly needs to be placed in a metal hard shell for assembly, but the outside of the electrode assembly is relatively soft and there is a risk of being damaged by the harder shell. In the conventional production process of new energy power batteries, a soft film is usually used to cover the entire electrode assembly from the bottom of the electrode assembly to the top cover before the electrode assembly is assembled with the metal shell, and then the soft film is hot-melted to form a bond with the plastic under the top cover. The soft film bonded in this way may fall off, causing the pole ear of the electrode assembly to contact the metal shell and cause a short circuit. At the same time, the lower plastic needs to be hot-melted to form a bonding point with the soft film, and the lower plastic is usually thicker and occupies more internal space of the battery. In addition, after the battery is assembled, the pole ear of the electrode assembly may break and fold, causing the pole ear to be inserted into the diaphragm and pole piece, or causing the pole ear to be inserted into the soft film and contact the metal shell, which will cause the battery to short-circuit, and there may even be a risk of combustion and explosion.

[0038] In view of this, an embodiment of the present application provides a secondary battery, aiming to solve at least one of the above technical problems.

[0039] See also Figure 1 and Figure 2 The secondary battery of the embodiment of the present application includes a shell 10, an electrode assembly 20, a cap assembly 30 and a separator 40.

[0040] It should be understood that the shell 10 has a connected accommodating cavity 101 and an opening 102; the shell 10 provides external protection and isolation for the secondary battery, and can also play a role in heat dissipation, leakage prevention and mechanical support. It is an important component to ensure the performance and safety of the secondary battery.

[0041] The electrode assembly 20 is arranged in the accommodating cavity 101, and the electrode assembly 20 includes a main body 201 and a pole ear 202 connected to each other; the electrode assembly 20 is the core component of the secondary battery, and generally the electrode assembly 20 can be formed by winding or stacking a positive electrode sheet, a negative electrode sheet and a diaphragm; the main body 201 mainly includes a part of the electrode sheet containing active substances and a diaphragm separating the positive electrode sheet and the negative electrode sheet, which is used to store or release electrical energy so that the battery can be charged and discharged; the main function of the pole ear 202 is to provide centralized transmission of current, transfer charge from the main body 201 to other components, or transfer charge from other components to the part of the main body 201 containing active substances.

[0042] The cover assembly 30 is connected to the shell 10 and covers the opening 102 to close the accommodating cavity 101, so that the shell 10 has good sealing performance, which can prevent the leakage of chemical substances inside the secondary battery or the entry of external air, water vapor, etc. into the interior of the secondary battery. The cover assembly 30 includes a pole 301, which is located at the top or bottom of the secondary battery and is connected to the electrode assembly 20 to realize the transmission of charge and the charging and discharging of the battery. The pole 301 is usually made of metal material and has good conductivity and mechanical strength. It is responsible for connecting the electrode assembly 20 to the external circuit during the battery assembly process, and through the lead or connector, the charge can smoothly enter and exit the battery. The pole 301 plays a role in stabilizing the current and voltage output, and also has durability and reliability to ensure the performance and working safety of the battery.

[0043] The partition 40 is arranged in the accommodating cavity 101, and at least partly located between the body 201 and the cover assembly 30. The partition 40 is provided with a through hole 401, and the pole ear 202 passes through the through hole 401 and is electrically connected to the pole column 301. It should be understood that by providing the partition 40 to separate the body 201 from the cover assembly 30, and providing the through hole 401 for the pole ear 202 to pass through on the partition 40, on the one hand, the partition 40 can play a role in protecting the body 201, and can prevent the pole ear 202 from being broken or folded and then inserted into the body 201, causing a short circuit in the battery; on the other hand, the partition 40 can play a role in fixing and shaping the pole ear 202, avoiding the pole ear 202 from being loosely bonded, the pole ear 202 being inserted outward, puncturing the soft film, and contacting the metal shell 10, causing a short circuit in the battery. In some embodiments, the electrode assembly 20 is coated with an insulating film 50, and the partition 40 is arranged between the body 201 and the cover assembly 30, and is connected to the insulating film 50. By adopting a structure in which the partition 40 and the insulating film 50 are integrated, there is no need to hot-melt bond the cover plate assembly 30 and the insulating film 50, and the height of the plastic boss under the top cover can be reduced, or even the lower plastic boss can be eliminated, thereby improving the overall energy density of the battery.

[0044] For details, please refer to Figure 3 , Figure 6 and Figure 7As shown, the partition 40 has a first direction X and a second direction Y intersecting each other. Along the first direction X, the through hole 401 has a first size e mm, and the tab 202 has a second size s mm. Along the second direction Y, the through hole 401 has a third size f mm, and the tab 202 has a fourth size c mm, satisfying: 1.2≤e / s≤2; and satisfying: 1.2≤f / c≤2. e / s can be any value among 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or a range value between any two values; f / c can be any value among 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or a range value between any two values.

[0045] It should be noted that the first dimension e mm represents the short side dimension of the through hole 401 provided on the partition 40, the third dimension f mm represents the long side dimension of the through hole 401 provided on the partition 40, the second dimension s mm represents the thickness dimension of the tab 202, and the fourth dimension c mm represents the width dimension of the tab 202, wherein the width of the tab 202 corresponds to the long side of the through hole 401, and must satisfy: 1.2≤e / s≤2; and satisfy: 1.2≤f / c≤2. The tab 202 is formed by stacking a number of sub-tabs. Considering the assembly error of the tab 202, that is, the sub-tabs have a certain offset in the second direction Y, it is impossible to ensure that the sub-tabs overlap 100%. At the same time, the gap between the sub-tabs will cause the tab 202 to swell, that is, the thickness of the tab 202 in the first direction X has a certain amount of variation. Therefore, satisfying 1.2≤e / s≤2 and 1.2≤f / c≤2 can ensure that the tab 202 can smoothly pass through the through hole 401, and the through hole 401 can provide the tab 202 with sufficient swelling space and offset space; on the other hand, the through hole 401 can assist the tab 202 in folding and positioning, and at the same time, the tab 202 also plays a role in positioning the assembly of the partition 40 after being folded. If the through hole 401 is too small, after the tab 202 is assembled, the tab 202 may be partially squeezed and deformed, and damaged; if the through hole 401 is too large, the assembly position of the partition 40 will be greatly offset, and the tab 202 cannot be bent normally, which increases the difficulty of assembly.

[0046] In some embodiments, see Figure 1 , Figure 2 , Figure 3 and Figure 8As shown, the cover plate assembly 30 is further provided with an explosion-proof valve 60 and a liquid injection hole 302, and a first hole 403 and a second hole 404 are provided on the partition plate 40, the first hole 403 is provided corresponding to the explosion-proof valve 60, and the second hole 404 is provided corresponding to the liquid injection hole 302. It should be understood that the first hole 403 provided on the partition plate 40 directly facing the explosion-proof valve 60 can facilitate the discharge of the gas generated inside the body 201, and the second hole 404 provided on the partition plate 40 directly facing the liquid injection hole 302 can facilitate the improvement of the liquid injection efficiency.

[0047] In some embodiments, see Figure 6 and Figure 7 As shown, the partition 40 has a third direction Z, and along the third direction Z, the positive projection of the pole 301 on the partition 40 is located outside the through hole 401. It should be understood that the positional relationship between the pole 301 and the through hole 401 can ensure that the bending part of the pole lug 202 avoids the pole 301. On the one hand, it effectively avoids the excessive warping of the bending part of the pole lug 202, which affects the connection stability between the pole lug 202 and the pole 301; on the other hand, it can ensure that the contact part of the pole lug 202 with the pole 301 is relatively flat, so that there is enough welding area with the pole 301 and the possibility of cold welding during welding is reduced, thereby improving the current capacity.

[0048] In some embodiments, see Figure 6 and Figure 7 As shown, the partition 40 has a third direction Z, and along the third direction Z, the partition 40 has a sixth dimension h mm, which satisfies: 0.5≤h≤3. It should be noted that the sixth dimension h is the thickness of the partition 40, and the thickness of the partition 40 is between 0.5mm and 3mm. If h<0.5, the thickness of the partition 40 is too thin, and it is easy to deform and bend, so that a gap is easily generated between the pole ear 202 and the secondary battery body 201, which is not conducive to the positioning and assembly between the pole ear 202 and the through hole 401. If h>3, the thickness of the partition 40 is too thick, which affects the welding connection between the pole ear 202 and the pole 301, and increases the battery cost. At the same time, if the partition 40 is too thick, it will occupy more internal space of the shell 10, and reduce the overall energy density of the battery.

[0049] In some embodiments, please refer to Figure 5 and Figure 7As shown, the tab 202 includes a first connecting section 2021 and a second connecting section 2022. The first connecting section 2021 is connected to the body 201 and passes through the through hole 401. The second connecting section 2022 is located on the side of the partition 40 facing away from the body 201 and is connected to the end of the first connecting section 2021 away from the body 201. The second connecting section 2022 extends toward the first direction X and is sandwiched between the partition 40 and the pole 301, and is electrically connected to the pole 301. It should be understood that the first connecting section 2021 and the second connecting section 2022 of the tab 202 can be an integrated structure or a split structure. One end of the first connection section 2021 is connected to the body 201, and the other end passes through the through hole 401 and can be bent at the through hole 401. The bent portion of the first connection section 2021 is separated from the body 201 by the partition 40 and connected to the second connection section 2022. After the second connection section 2022 is welded to the pole 301, during the core assembly process, the partition 40 and the pole 301 can jointly clamp the second connection section 2022 to shape and fix the second connection section 2022. The through hole 401 can guide the first connection section 2021 to bend, and the partition 40 can limit the bending angle of the first connection section 2021, thereby reducing the risk of damage at the bending portion of the pole ear 202. At the same time, the partition 40 can protect the pole ear 202 side of the body 201, avoiding the risk of the pole ear 202 being inserted.

[0050] In some embodiments, see Figure 8 As shown, a bonding layer 402 is further provided on the side of the partition 40 facing the cover plate assembly 30, and the pole ear 202 passes through the through hole 401 and is connected to the bonding layer 402. It should be understood that the bonding layer 402 can be a bonding material, such as a double-sided adhesive, which is attached to the partition 40 to bond and fix the portion of the pole ear 202 passing through the through hole 401, so as to improve the stability of the pole ear 202 after assembly, avoid stress concentration at the bending part of the pole ear 202, cause relative displacement between the pole ear 202 and the partition 40, and affect the reliability of the connection between the pole ear 202 and the pole 301.

[0051] In some embodiments, please refer to Figure 2 and Figure 8 As shown, the pole ear 202 has a weld mark area 2023 formed by welding with the pole column 301, and the separator 40 has a third direction Z, and the first direction X, the second direction Y and the third direction Z intersect each other, and the adhesive layer 402 covers the weld mark area 2023 along the third direction Z. It should be understood that the adhesive layer 402 covers the weld mark area 2023, which can effectively prevent the residual metal particles in the welding area from falling off during the injection of electrolyte or use and entering the secondary battery after the pole ear 202 and the pole column 301 are welded, causing safety hazards such as micro short circuit or short circuit, and accelerating the battery capacity decay rate.

[0052] In some embodiments, see Figure 8 As shown, the secondary battery also includes an insulating film 50, which is disposed in the accommodating cavity 101 and covers the body 201. The insulating film 50 is at least partially disposed on both sides of the partition 40 along the first direction X and connected to the partition 40. It should be understood that the connection between the insulating film 50 and the partition 40 can be an integrally formed structure. In some embodiments, the side of the partition 40 close to the insulating film 50 has an extension extending along the third direction Z, and the extension is at least partially located between the electrode assembly 20 and the insulating film 50. The extension is covered by the insulating film 50 to achieve the connection between the partition 40 and the insulating film 50. In some embodiments, the partition 40 is only located between the body 201 and the cover plate assembly 30, and the insulating film 50 can cover the outer edge of the partition 40 while avoiding the through hole 401 on the partition 40 to avoid interference with the section of the pole ear 202 to be welded. In some embodiments, the insulating film 50 is provided with an assembly hole, and the partition 40 is connected to the insulating film 50 by penetrating the assembly hole on the insulating film 50, or the partition 40 is provided with an assembly hole, and the insulating film 50 is connected to the partition 40 by penetrating the assembly hole on the partition 40. At the same time, in order to improve the assembly efficiency, a certain length (such as 1 / 4") can be reserved at the connection between the insulating film 50 and the partition 40 during the core assembly process. Figure 7 As shown), it can provide redundant stretching for the flipping of the partition 40 to avoid tearing at the connection between the insulating film 50 and the partition 40; at the same time, the redundant length of the insulating film 50 can cooperate with the cover plate assembly 30 to improve the assembly stability.

[0053] In some embodiments, please refer to Figure 6 , Figure 7 As shown, along the first direction X, the through hole 401 and the insulating film 50 have a spacing of d mm, and the body 201 has a fifth dimension of z mm, satisfying: 0≤d / z≤0.3. It should be understood that the spacing between the through hole 401 and the insulating film 50 is expressed as the shortest distance from the outer edge of the through hole 401 to the insulating film 50. When d / z is 0, that is, the spacing between the through hole 401 and the insulating film 50 is 0, at this time, a notch is opened on the side of the partition 40 close to the insulating film 50, and the through hole 401 is surrounded by the partition 40 and the insulating film 50. When 0<d / z≤0.3, that is, along the first direction X, there is a shortest distance between the through hole 401 and the insulating film 50. At this time, the larger the d / z ratio is, the longer the shortest distance between the through hole 401 and the insulating film 50 is. In order to prevent the pole lug 202 from passing through the through hole 401 and the raised area formed above the through hole 401 affecting the welding area between the pole lug 202 and the pole 301, d / z can be controlled within 0.3 to ensure that the pole lug 202 and the pole 301 have sufficient welding area, while ensuring the current carrying capacity and the stability of the connection between the pole lug 202 and the pole 301.

[0054] The separators 40 of the following embodiments are assembled, and the qualified assembly rate of the secondary battery (square lithium-ion battery) after the core is assembled into the shell is observed. When the tabs 202 are damaged, the separators 40 are bent and deformed, the separators 40 are offset, resulting in a large deviation between the first hole 403 and the explosion-proof valve 60, a large deviation between the second hole 404 and the injection hole 302, redundant wrinkles of the insulating film 50, and the case cannot be inserted, it is considered to be unqualified. Each embodiment or comparative example assembles 100 secondary batteries, and the qualified assembly rate = (1-the number of unqualified assembled secondary batteries / the number of assembled secondary batteries) × 100%.

[0055] Hereinafter, the present application compares the test results through Examples 1 to 19 and Comparative Examples 1 to 9.

[0056]

[0057] Results analysis shows that:

[0058] In Examples 1 to 19, when 1.2≤e / s≤2 and 1.2≤f / c≤2 are satisfied, the qualified rate of assembly after the secondary battery core is assembled into the shell is 100%. In Comparative Examples 1, 3 and 4, when f / c is 1.2 and e / s<1.2, that is, along the first direction X, the gap between the tab 202 and the partition 40 is too small, and the tab 202 is prone to greater stress contact with the partition 40 during the folding process, resulting in damage to the tab 202 at the bend, bending and deformation of the partition 40, and displacement of the partition 40, thereby affecting the qualified rate of assembly. In Comparative Examples 2 and 5, when f / c is 1.2 and e / s>2, that is, along the first direction X, the first dimension of the through hole 401 is too large, and the gap between the pole ear 202 and the partition 40 is too large. During the core closing process, the pole ear 202 cannot be folded smoothly, and the folded part is prone to warping; at the same time, the partition 40 is prone to displacement, resulting in a large deviation between the first hole 403 and the explosion-proof valve 60, and a large deviation between the second hole 404 and the injection hole 302; in addition, redundant wrinkles of the insulating film 50 are prone to occur, and the shell cannot be inserted.

[0059] In Comparative Examples 6 and 8, when e / s is 1.33 and f / c is less than 1.2, along the second direction Y, the gap between the pole ear 202 and the partition 40 is too small, and the pole ear 202 may have a mismatch in the second direction Y, resulting in the inability to ensure 100% overlap of the pole ear 202, causing the pole ear 202 to be unable to smoothly penetrate the through hole 401; after the pole ear 202 penetrates the through hole 401, along the second direction Y, the pole ear 202 contacts the inner wall of the through hole 401, and there is stress extrusion, so that the pole ear 202 has redundant wrinkles on both sides of the second direction Y, which increases the difficulty of folding the pole ear 202. In Comparative Examples 7 and 9, when e / s is 1.33 and f / c>2, along the second direction Y, the gap between the pole tab 202 and the partition 40 is too large, which is not conducive to the positioning of the pole tab 202 in the second direction Y. During the core assembly process, the partition 40 is easily offset, resulting in a large deviation between the first hole 403 and the explosion-proof valve 60, and a large deviation between the second hole 404 and the injection hole 302. After the pole tab 202 is assembled, the secondary battery cannot be assembled normally.

[0060] It should be understood that in the above embodiments of the present application, the first dimension e mm, the second dimension s mm, the third dimension f mm, the fourth dimension c mm, the fifth dimension z mm, the sixth dimension h mm and the spacing d mm can all be measured by a ruler.

[0061] The present application also discloses a battery pack, including the secondary battery of the above embodiment. The battery pack of the present application includes the secondary battery of the above embodiment, and thus can have all the technical features and technical effects of the above secondary battery, which will not be described in detail here.

[0062] The secondary battery and battery pack provided in the embodiments of the present application are introduced in detail above, and the principles and implementation methods of the present application are explained by applying specific examples. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application; ordinary technicians in this field should understand that: they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A secondary battery, characterized in that: include: A housing (10), the housing (10) having a communicating accommodation cavity (101) and an opening (102); An electrode assembly (20), the electrode assembly (20) being arranged in the accommodating cavity (101), the electrode assembly (20) comprising a body (201) and a tab (202) connected to each other; a cover plate assembly (30), the cover plate assembly (30) being connected to the housing (10) and covering the opening (102), the cover plate assembly (30) comprising a pole (301); a partition (40), the partition (40) being arranged in the accommodating cavity (101) and at least partially located between the body (201) and the cover plate assembly (30), the partition (40) being provided with a through hole (401), the pole lug (202) passing through the through hole (401) and being electrically connected to the pole (301); The partition (40) has a first direction (X) and a second direction (Y) intersecting each other. Along the first direction (X), the through hole (401) has a first size e mm, and the tab (202) has a second size s mm. Along the second direction (Y), the through hole (401) has a third size f mm, and the tab (202) has a fourth size c mm, satisfying: 1.2≤e / s≤2; And it satisfies: 1.2≤f / c≤2.

2. The secondary battery according to claim 1, characterized in that: The pole lug (202) comprises a first connecting section (2021) and a second connecting section (2022); The first connecting section (2021) is connected to the body (201) and passes through the through hole (401); The second connecting section (2022) is located on a side of the partition (40) facing away from the main body (201), and is connected to an end of the first connecting section (2021) away from the main body (201); the second connecting section (2022) extends toward the first direction (X), and is sandwiched between the partition (40) and the pole (301), and is electrically connected to the pole (301).

3. The secondary battery according to claim 1, characterized in that: A bonding layer (402) is also provided on the side of the partition (40) facing the cover plate assembly (30), and the pole ear (202) passes through the through hole (401) and is connected to the bonding layer (402).

4. The secondary battery according to claim 3, characterized in that: The pole lug (202) has a weld mark area (2023) formed by welding with the pole (301), the partition (40) has a third direction (Z), the first direction (X), the second direction (Y) and the third direction (Z) intersect each other, and along the third direction (Z), the adhesive layer (402) covers the weld mark area (2023).

5. The secondary battery according to claim 1, characterized in that: The secondary battery further comprises: An insulating film (50), the insulating film (50) is arranged in the accommodating cavity (101) and covers the main body (201), and the insulating film (50) is at least partially arranged on both sides of the partition (40) along the first direction (X) and connected to the partition (40).

6. The secondary battery according to claim 5, characterized in that: Along the first direction (X), the through hole (401) and the insulating film (50) have a spacing of d mm, and the body (201) has a fifth dimension of z mm, satisfying: 0≤d / z≤0.

3.

7. The secondary battery according to claim 1, characterized in that: The cover plate assembly (30) is also provided with an explosion-proof valve (60) and a liquid injection hole (302); the partition plate (40) is provided with a first hole (403) and a second hole (404); the first hole (403) is arranged corresponding to the explosion-proof valve (60), and the second hole (404) is arranged corresponding to the liquid injection hole (302).

8. The secondary battery according to claim 1, characterized in that: The partition (40) has a third direction (Z), the first direction (X), the second direction (Y) and the third direction (Z) intersect each other, and along the third direction (Z), the orthographic projection of the pole (301) on the partition (40) is located outside the through hole (401).

9. The secondary battery according to claim 1, characterized in that: The partition (40) has a third direction (Z), the first direction (X), the second direction (Y) and the third direction (Z) intersect each other, and along the third direction (Z), the partition (40) has a sixth dimension h mm, satisfying: 0.5≤h≤3.

10. A battery pack, characterized in that: The invention comprises the secondary battery according to any one of claims 1 to 9.

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