Secondary battery
By setting a thickness reduction zone on the packaging member of the lithium-ion battery, the tensile strength of the packaging member is enhanced, the seal failure problem at the aluminum-plastic film packaging is solved, and the safety and reliability of the battery is improved.
Patent Information
- Application Number
- CN202422354489.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2025-08-19
- Estimated Expiration
- 2034-09-25
AI Technical Summary
The aluminum-plastic film packaging of existing lithium-ion batteries is prone to failure due to the low tensile strength, resulting in seal failure and safety risks.
By optimizing the structure of the package member, it is possible to provide a thickness reduction area in the extension direction of the electrode leads, and enhance the tensile strength of the package member, including a thickness reduction area arranged symmetrically or asymmetrically, forming a reinforcement structure to improve packaging reliability.
It improves the tensile strength at the positive and negative electrode package, enhances the safety and reliability of the electrode assembly, reduces the risk of seal failure, and improves the safety performance of the secondary battery.
Smart Images
Figure CN223245756U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a secondary battery. Background Art
[0002] With the development of the new energy industry, lithium-ion batteries are widely used in our daily lives. Lithium-ion electrode assemblies are divided into cylindrical, prismatic, and soft-pack types. Soft-pack electrode assemblies are widely used due to their high energy density and high group utilization rate.
[0003] Soft-pack lithium-ion electrode assemblies are favored for their lightweight, easy-to-form, and easy-to-package properties, thanks to their aluminum-plastic film outer shell. However, during use, as the electrode assembly circulates and stores, a large amount of gas may be generated inside the electrode assembly, causing significant internal pressure at the aluminum-plastic film seal. Furthermore, with increasing service life, the aluminum-plastic film ages. Combined with internal pressure and aging, the aluminum-plastic film seal fails, allowing air to enter the electrode assembly, corroding the aluminum-plastic film and even posing safety risks. Because the electrode assembly has folded edges on both sides and is subject to pressure from the upper and lower covers within the module, seal failure typically occurs at the positive and negative tab seals. Utility Model Content
[0004] The technical problem to be solved by the present invention is to overcome the defect in the prior art that the aluminum-plastic film on the sealant loses its sealing effect after being subjected to force, that is, the aluminum-plastic film has low tensile strength, and to provide a secondary battery. The secondary battery optimizes the structure of the packaging component, thereby improving the tensile strength of the positive and negative electrode packaging, improving the packaging reliability, and thus achieving improved safety and reliability of the electrode assembly.
[0005] The utility model solves the above technical problems through the following technical solutions:
[0006] The utility model provides a secondary battery, which includes an electrode assembly, a shell, an electrode lead and a packaging component, the shell includes a packaging film, the internal space of the shell accommodates the electrode assembly, the packaging film and the electrode lead are packaged by the packaging component, one end of the electrode lead is arranged in the internal space of the shell and is connected to the electrode assembly, and the other end extends outward through the packaging component, the electrode lead includes at least a first outer surface and a second outer surface, the packaging component is located between the first outer surface, the second outer surface and the packaging film, and the packaging component is provided with at least one thickness reduction area along the extension direction of the electrode lead.
[0007] In the present invention, the electrode assembly may be a battery core; the electrode lead generally includes a metal strip.
[0008] In some embodiments, the packaging member on the first outer surface side and the packaging member on the second outer surface side are symmetrically arranged with respect to the electrode lead.
[0009] The “symmetrical setting” includes: symmetry of position and / or symmetry of shape and structure.
[0010] In the above technical solution, the tensile strength of both sides of the electrode lead can be improved simultaneously through symmetrical arrangement; moreover, the design is also convenient for standardized processing and production.
[0011] In some embodiments, the packaging member on the first outer surface side and the packaging member on the second outer surface side are asymmetrically arranged relative to the electrode lead.
[0012] The "asymmetric setting" may be: the outer edge lengths of the packaging component on the first outer surface side and the packaging component on the second outer surface side are different; or the thicknesses of the packaging component on the first outer surface side and the packaging component on the second outer surface side are different.
[0013] Among them, the "asymmetric setting" may be: the packaging component has only one thickness reduction zone along the extension direction of the electrode lead, that is, the packaging component on the first outer surface side contains a thickness reduction zone, and the thickness of the packaging component at each position on the second outer surface side is uniform and does not contain a thickness reduction zone.
[0014] In the above technical solution, when the packaging of the packaging film is an asymmetric structure, the "asymmetric setting" can adapt to the packaging situation of the packaging film and achieve the effect of improving the tensile strength; further, only a thickness reduction area is set on one side of the packaging film where there is a risk of tearing, so as to achieve the improvement of tensile strength and achieve the anti-peeling effect.
[0015] In some embodiments, in the packaging component on the first outer surface side or the packaging component on the second outer surface side, along the extension direction of the electrode lead and in the cross section in the thickness direction of the electrode lead, the outer edge of the thickness reduction zone has an arc-shaped structure concave toward the electrode lead.
[0016] In the above technical solution, the angle between the tangent line of the initial outer edge of the reduced thickness zone and the electrode lead is the largest, and the tensile strength is greatest at this location. As the electrode lead extends, the angle between the tangent line of the outer edge of the reduced thickness zone and the electrode lead gradually decreases, and the tensile strength also gradually decreases. This can effectively improve the tensile strength and peel resistance of the packaging film in the early stages of failure, thereby preventing failure of the packaging film at an early stage.
[0017] In a specific embodiment, the packaging component on the first outer surface side or the packaging component on the second outer surface side is further provided with a constant thickness area; compared with the thickness reduction area, the constant thickness area is provided on a side closer to the electrode assembly.
[0018] In the above technical solution, a "flat first and concave later" packaging component structure is set; wherein, the "concave later" structure can form a larger angle between the initial part of the thickness reduction area and the electrode lead, which can better improve the tensile strength and increase the packaging film's anti-peeling ability in the early stage of packaging film failure; the "flat first" structure is conducive to the packaging of the packaging film and the packaging component, avoiding the front end of the "concave part" of the packaging component being too sharp, which may cause the packaging film of the outer shell to be punctured.
[0019] In some embodiments, in the packaging component on the first outer surface side or the packaging component on the second outer surface side, an outer edge of the thickness reduction area is a straight line structure in a cross section along the extension direction of the electrode lead and in the thickness direction of the electrode lead.
[0020] In the above technical solution, each position on the outer edge of the packaging component has a large tensile strength, which can continuously improve the anti-peeling effect.
[0021] In some embodiments, on the first outer surface or the second outer surface, the packaging member is provided with at least two thickness-reduced regions along an extension direction of the electrode lead.
[0022] In the above technical solution, by setting up multiple thickness reduction areas, a reinforcement structure can be formed to form two anti-peeling areas; when one anti-peeling area fails, other anti-peeling areas can be used for protection, so that the anti-peeling can continue to be effective.
[0023] In the present invention, the packaging component generally includes sealant.
[0024] In some embodiments, the thickness of the packaging component is greater than or equal to 0.5 mm and less than or equal to 6 mm.
[0025] In a specific embodiment, the upper limit of the thickness of the packaging component is 2-6 mm, preferably 2-5 mm.
[0026] In a specific embodiment, the lower limit of the packaging component is 0.5-1.5 mm.
[0027] In the above technical solution, the purpose of setting the upper and lower limits of the thickness of the packaging component is to ensure that a structure with reduced thickness can be formed on the packaging component to enhance the tensile effect; the upper limit thickness of the packaging component is guaranteed not to exceed the thickness of the electrode assembly; the lower limit thickness of the packaging component avoids the thickness being too small to have the function of insulation and bonding.
[0028] In some embodiments, an angle between an outer edge of the reduced thickness region and an extension direction of the electrode lead is greater than or equal to 2° and less than or equal to 15°.
[0029] In the above technical solution, by setting the size of the angle, the thickness reduction area forms a slope in the extension direction of the electrode lead, thereby improving the tensile strength of the aluminum-plastic film at the packaging location.
[0030] Wherein, along the extension direction of the electrode lead and on the cross section in the thickness direction of the electrode lead, when the outer edge of the thickness reduction area is a straight line structure, the angle is the angle between the straight line and the electrode lead.
[0031] In the above technical solution, along the extension direction of the electrode lead, the angle between the outer edge tangent line of the reduced thickness area and the electrode lead remains unchanged, and the tensile strength at each position on the reduced thickness area is substantially the same.
[0032] In the present invention, the packaging film can be a conventional aluminum-plastic film in the art.
[0033] In some embodiments, along the extension direction of the electrode lead, both ends of the packaging member extend beyond both ends of the packaging area formed by the packaging film and the packaging member.
[0034] In the above technical solution, the problem of the metal layer in the packaging film being directly connected to the electrode lead when the packaging film is broken, which causes a short circuit, can be effectively avoided; thereby improving the sealing performance of the secondary battery and playing an insulating role.
[0035] The positive progress effect of this utility model is:
[0036] In the secondary battery of the present application, by adjusting the thickness of the packaging components on both sides of the positive and negative electrode leads, when the air pressure inside the electrode assembly is relatively high, the stretching angle between the aluminum-plastic film and the packaging components is increased, thereby increasing the tensile strength of the packaging, improving the packaging reliability, and thus improving the safety performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1 Schematic diagram of the structure of the secondary battery of Examples 1-4 of the present invention.
[0038] Figure 2 This is a schematic structural diagram of the packaging component of Example 1 of the present utility model.
[0039] Figure 3 This is a schematic diagram of the force decomposition of the packaging component with aluminum-plastic film in Example 1 of the present utility model.
[0040] Figure 4 This is a schematic structural diagram of the packaging component of Example 2 of the present utility model.
[0041] Figure 5 This is a schematic diagram of the force decomposition of the packaging component with aluminum-plastic film in Example 2 of the present utility model.
[0042] Figure 6 This is a schematic structural diagram of the packaging component of Example 3 of the present utility model.
[0043] Figure 7 This is a schematic structural diagram of the packaging component of Example 4 of the present utility model.
[0044] Figure 8 Schematic diagram of the structure of the packaging component of comparative example 1.
[0045] Figure 9 Schematic diagram of force decomposition of the packaging component with aluminum-plastic film in comparative example 1.
[0046] Description of reference numerals:
[0047] Electrode assembly 1
[0048] Shell 2
[0049] Electrode lead 3
[0050] First outer surface 31
[0051] Second outer surface 32
[0052] Package component 4
[0053] Reduced thickness region 41
[0054] Aluminum plastic film 5
[0055] Hot pressing section 51
[0056] Extension section 52. DETAILED DESCRIPTION
[0057] The present invention will be described more clearly and completely with reference to the following preferred embodiments and the accompanying drawings.
[0058] Example 1
[0059] This embodiment discloses a secondary battery. Figure 1 Schematic diagram of the structure of the secondary battery of this embodiment; Figure 2This is a schematic diagram of the structure of the packaging member 4 of this embodiment. This secondary battery includes an electrode assembly 1, an outer casing 2, an electrode lead 3, and a packaging member 4. The outer casing 2 includes a packaging film. The inner space of the outer casing 2 accommodates the electrode assembly 1. The packaging film and the electrode lead 3 are encapsulated by the packaging member 4. One end of the electrode lead 3 is located within the inner space of the outer casing 2 and connected to the electrode assembly 1, while the other end extends outward through the packaging member 4. The electrode lead 3 includes a first outer surface 31 and a second outer surface 32. The packaging member 4 is located between the first outer surface 31, the second outer surface 32, and the packaging member 4. The packaging member 4 on the first outer surface 31 side and the packaging member 4 on the second outer surface 32 side each have a reduced thickness region 41 along the extension direction of the electrode lead 3.
[0060] The packaging member 4 on the first outer surface 31 side and the packaging member 4 on the second outer surface 32 side are symmetrically arranged with respect to the electrode lead 3 .
[0061] In the packaging member 4 on the first outer surface 31 side or the packaging member 4 on the second outer surface 32 side, the outer edge of the reduced thickness region 41 is a straight line structure in a cross section along the extension direction of the electrode lead 3 and in the thickness direction of the electrode lead 3.
[0062] In the packaging member 4, the thickness of the end close to the electrode assembly 1 is 6 mm, and the thickness of the end away from the electrode assembly 1 is 2 mm; the angle between the outer edge of the thickness reduction area 41 and the electrode lead 3 is 15°;
[0063] The packaging film is an aluminum-plastic film 5, which includes a hot pressing section 51 and an extension section 52. The hot pressing section 51 is attached to the outer surface of the packaging component 4, and the extension section 52 continues to extend from the end of the packaging component 4 close to the electrode assembly 1 in a direction away from the packaging component 4.
[0064] In this embodiment, the tensile strength of both sides of the electrode lead 3 can be improved at the same time; moreover, the design is also convenient for standardized processing and production; each position on the outer edge of the packaging component 4 has a large tensile strength, which can continuously improve the anti-peeling effect.
[0065] Example 2
[0066] This embodiment discloses a secondary battery. Figure 4This is a schematic diagram of the structure of the packaging member 4 of this embodiment. This secondary battery includes an electrode assembly 1, an outer casing 2, an electrode lead 3, and a packaging member 4. The outer casing 2 includes a packaging film. The inner space of the outer casing 2 accommodates the electrode assembly 1. The packaging film and the electrode lead 3 are encapsulated by the packaging member 4. One end of the electrode lead 3 is located within the inner space of the outer casing 2 and connected to the electrode assembly 1, while the other end extends outward through the packaging member 4. The electrode lead 3 includes a first outer surface 31 and a second outer surface 32. The packaging member 4 is located between the first outer surface 31, the second outer surface 32, and the packaging member 4. The packaging member 4 on the first outer surface 31 side and the packaging member 4 on the second outer surface 32 side each have a reduced thickness region 41 along the extension direction of the electrode lead 3.
[0067] The packaging member 4 on the first outer surface 31 side and the packaging member 4 on the second outer surface 32 side are symmetrically arranged with respect to the electrode lead 3 .
[0068] In the packaging component 4 on the first outer surface 31 side or the packaging component 4 on the second outer surface 32 side, along the extension direction of the electrode lead 3 and in the cross section in the thickness direction of the electrode lead 3, the outer edge of the thickness reduction area 41 is an arc-shaped structure concave toward the electrode lead 3.
[0069] The packaging component 4 on the first outer surface 31 side or the packaging component 4 on the second outer surface 32 side is further provided with a constant thickness area; compared with the reduced thickness area 41 , the constant thickness area is provided on a side closer to the electrode assembly 1 .
[0070] In the packaging component 4, the thickness of the uniform thickness region is 4 mm, the initial thickness of the reduced thickness region 41 is the same as the thickness of the uniform thickness region, and the terminal thickness of the reduced thickness region 41 is 1 mm;
[0071] The packaging film is an aluminum-plastic film 5, which includes a hot pressing section 51 and an extension section 52. The hot pressing section 51 is attached to the outer surface of the packaging component 4, and the extension section 52 continues to extend from the end of the packaging component 4 close to the electrode assembly 1 in a direction away from the packaging component 4.
[0072] In this embodiment, a "flat first and concave later" structure of the packaging component 4 is set; wherein, the "concave later" structure can form a larger angle between the initial part of the thickness reduction area 41 and the electrode lead 3, which can better improve the tensile strength and increase the packaging film's anti-peeling ability in the early stage of packaging film failure; the "flat first" structure is conducive to the packaging of the packaging film and the packaging component 4, avoiding the front end of the "concave part" of the packaging component 4 being too sharp, which may cause the packaging film of the shell 2 to be punctured.
[0073] Example 3
[0074] This embodiment discloses a secondary battery. Figure 6Figure 4 is a schematic diagram of the structure of the packaging member 4 of this embodiment. The secondary battery comprises an electrode assembly 1, an outer casing 2, an electrode lead 3, and a packaging member 4. The outer casing 2 comprises a packaging film, the interior of which houses the electrode assembly 1. The packaging film and the electrode lead 3 are encapsulated by the packaging member 4. One end of the electrode lead 3 is disposed within the interior of the outer casing 2 and connected to the electrode assembly 1, while the other end extends outward through the packaging member 4. The electrode lead 3 comprises a first outer surface 31 and a second outer surface 32. The packaging member 4 is positioned between the first outer surface 31, the second outer surface 32, and the packaging film. The packaging member 4 on the first outer surface 31 and the packaging member 4 on the second outer surface 32 are asymmetrically disposed relative to the electrode lead.
[0075] In the packaging component 4 on the side of the first outer surface 31, along the extension direction of the electrode lead 3, the thickness at the end close to the electrode assembly 1 is 3 mm, and the thickness at the end away from the electrode assembly 1 is 0.5 mm; in the packaging component 4 on the side of the first outer surface 31, the angle between the thickness reduction area 41 and the electrode lead 3 is 10°.
[0076] The outer edge of the packaging member 4 on the second outer surface 32 side is parallel to the electrode lead 3 ; the thickness of the packaging member 4 on the second outer surface 32 side is 3 mm.
[0077] The packaging film is an aluminum-plastic film 5, which includes a hot pressing section 51 and an extension section 52. The hot pressing section 51 is attached to the outer surface of the packaging component 4, and the extension section 52 continues to extend from the end of the packaging component 4 close to the electrode assembly 1 in a direction away from the packaging component 4.
[0078] In this embodiment, only one thickness reduction area 41 is provided on one side of the electrode lead 3 to improve the tensile strength and achieve the anti-peeling effect.
[0079] Example 4
[0080] This embodiment discloses a secondary battery. Figure 7 Figure 4 is a schematic diagram of the structure of the packaging member 4 of this embodiment. The secondary battery comprises an electrode assembly 1, an outer casing 2, an electrode lead 3, and a packaging member 4. The outer casing 2 comprises a packaging film, the interior of which houses the electrode assembly 1. The packaging film and the electrode lead 3 are encapsulated by the packaging member 4. One end of the electrode lead 3 is disposed within the interior of the outer casing 2 and connected to the electrode assembly 1, while the other end extends outward through the packaging member 4. The electrode lead 3 comprises a first outer surface 31 and a second outer surface 32. The packaging member 4 is positioned between the first and second outer surfaces 31, 32, and the packaging film. The packaging member 4 on the first outer surface 31 side has two reduced-thickness regions 41 along the extension direction of the electrode lead 3.
[0081] In the packaging component 4 on the first outer surface 31 side, along the extension direction of the electrode lead 3, the thicknesses at both ends of the first thickness reduction area 41 are 6 mm and 4 mm respectively, the thickness of the middle area is 4 mm, and the thicknesses at both ends of the second thickness reduction area 41 are 4 mm and 2 mm respectively.
[0082] The outer edge of the packaging member 4 on the second outer surface 32 side is parallel to the electrode lead 3 ; the thickness of the packaging member 4 on the second outer surface 32 side is 4 mm.
[0083] The packaging film is an aluminum-plastic film 5, which includes a hot pressing section 51 and an extension section 52. The hot pressing section 51 is attached to the outer surface of the packaging component 4, and the extension section 52 continues to extend from the end of the packaging component 4 close to the electrode assembly 1 in a direction away from the packaging component 4.
[0084] In this embodiment, a plurality of thickness reduction areas 41 are provided to form a reinforcement structure and two anti-peeling areas. When one anti-peeling area fails, other anti-peeling areas can be used for protection, so that the anti-peeling effect can continue to be effective.
[0085] Comparative Example 1
[0086] This comparative example discloses a secondary battery, Figure 8 The figure is a schematic diagram of the structure of the packaging member 4 of this comparative example. The secondary battery comprises an electrode assembly 1, an outer casing 2, an electrode lead 3, and a packaging member 4. The outer casing 2 comprises a packaging film, the interior of which houses the electrode assembly 1. The packaging film and the electrode lead 3 are encapsulated by the packaging member 4. One end of the electrode lead 3 is disposed within the interior of the outer casing 2 and connected to the electrode assembly 1, while the other end extends outward through the packaging member 4. The electrode lead 3 comprises a first outer surface 31 and a second outer surface 32. The packaging member 4 is positioned between the first outer surface 31, the second outer surface 32, and the packaging film.
[0087] The packaging component 4 is designed to have a uniform thickness, and its thickness is 4 mm.
[0088] The packaging film is an aluminum-plastic film 5, which includes a hot pressing section 51 and an extension section 52. The hot pressing section 51 is attached to the outer surface of the packaging component 4, and the extension section 52 continues to extend from the end of the packaging component 4 close to the electrode assembly 1 in a direction away from the packaging component 4.
[0089] Effect Example 1
[0090] A force F of the same magnitude and direction was applied to the aluminum-plastic film in the secondary battery of Example 1, the aluminum-plastic film in the secondary battery of Example 2, and the aluminum-plastic film in the secondary battery of Comparative Example 1, respectively, to simulate the force generated by a large amount of gas inside the electrode assembly.
[0091] Figure 3Schematic diagram of force decomposition of the packaging component with aluminum-plastic film in Example 1. In the secondary battery of Example 1, at point A, the force F can be decomposed into F A1 and upward F A2 , where F A1 No effect, F A2 is the tensile force for tearing the aluminum-plastic film, F and F A1 The angle between them is β1, F A1 The angle between the package and the plane is θ1, which is the angle between the outer edge of the package and the electrode lead. A2 =sinβ1·F.
[0092] Figure 5 Schematic diagram of force decomposition of the packaging component with aluminum-plastic film in Example 2. In the secondary battery of Example 2, at point B, the force F can be decomposed into F B1 and upward F B2 , where F B1 No effect, F B2 is the tensile force for tearing the aluminum-plastic film, F and F B1 The angle between them is β2, F B1 The angle with the plane is θ2, which is the angle between the tangent line of the outer edge of the packaging component at point B and the electrode lead. At point B, F B2 = sinβ2·F. At point C, the force F can be decomposed into the leftward force F C1 and upward F C2 , where F C1 No effect, F C2 is the tensile force for tearing the aluminum-plastic film, F and F C1 The angle between them is β3, F B1 The angle with the plane is θ3, which is the angle between the tangent line of the outer edge of the packaging component at point C and the electrode lead. At point C, F C2 = sinβ3·F. The magnitude and direction of the force F are the same, θ2+β2=θ3+β3; by comparison, we can see that when F is the same, since β2<β3, F B2 <F C2 ; At B of the encapsulated component, it has the maximum tensile strength.
[0093] Figure 9 This is a schematic diagram of the force decomposition of the packaging component with aluminum-plastic film in Comparative Example 1. The force F in the secondary battery of Comparative Example 1 can be decomposed into a leftward force F1 and an upward force F2. F1 has no effect, while F2 is the tensile force that tears the aluminum-plastic film. The angle between F and F1 is α. In Example 1, F2 = sinα·F.
[0094] When the force F is the same, Figure 3 and Figure 9It can be seen that θ1+β1=α, and it can be deduced that (sinβ1·F)<(sinα·F), so F A2 <F2; by Figure 5 and Figure 9 It can be seen that θ2+β2=θ3+β3=α, it can be deduced that (sinβ2·F)<(sinβ3·F)<(sinα·F), from which F B2 <F C2 <F2;
[0095] It can be seen that by designing the thickness of the packaging component in this application, the stretching angle between the aluminum-plastic film and the packaging component is increased, thereby improving the tensile strength of the packaging, improving the packaging reliability, and thus improving the safety performance.
Claims
1. A secondary battery comprising an electrode assembly, a housing, an electrode lead, and a packaging member, wherein the housing comprises a packaging film, the interior space of the housing accommodates the electrode assembly, the packaging film and the electrode lead are packaged by the packaging member, one end of the electrode lead is disposed in the interior space of the housing and connected to the electrode assembly, and the other end extends outward through the packaging member, characterized in that: The electrode lead includes at least a first outer surface and a second outer surface. The packaging member is located between the first outer surface, the second outer surface and the packaging film. The packaging member is provided with at least one thickness-reduced region along the extending direction of the electrode lead.
2. The secondary battery according to claim 1, wherein The packaging member on the first outer surface side and the packaging member on the second outer surface side are symmetrically arranged with respect to the electrode lead.
3. The secondary battery according to claim 1, wherein The packaging member on the first outer surface side and the packaging member on the second outer surface side are arranged asymmetrically with respect to the electrode lead.
4. The secondary battery according to claim 1, wherein In the packaging component on the first outer surface side or the packaging component on the second outer surface side, along the extension direction of the electrode lead and in the cross section in the thickness direction of the electrode lead, the outer edge of the thickness reduction area has an arc structure concave toward the electrode lead.
5. The secondary battery according to claim 4, wherein The packaging component on the first outer surface side or the packaging component on the second outer surface side is further provided with a constant thickness area; compared with the thickness reduction area, the constant thickness area is provided on a side closer to the electrode assembly.
6. The secondary battery according to claim 1, wherein In the packaging member on the first outer surface side or the packaging member on the second outer surface side, an outer edge of the reduced thickness region is a straight line structure in a cross section along the extension direction of the electrode lead and in the thickness direction of the electrode lead.
7. The secondary battery according to claim 1, wherein The packaging member on the first outer surface side or the packaging member on the second outer surface side is provided with at least two thickness-reduced regions along the extending direction of the electrode lead.
8. The secondary battery according to claim 1, wherein The thickness of the packaging component is greater than or equal to 0.5 mm and less than or equal to 6 mm.
9. The secondary battery according to claim 5, wherein An included angle between an outer edge of the thickness-reduced region and an extending direction of the electrode lead is greater than or equal to 2° and less than or equal to 15°.
10. The secondary battery according to claim 1, wherein Along the extending direction of the electrode lead, both ends of the packaging member extend beyond both ends of the packaging area formed by the packaging film and the packaging member.