Battery cell structure and laminated battery

Abstract

The invention belongs to the technical field of secondary batteries, and mainly relates to a battery cell structure, the battery cell structure comprises a positive pole piece, a diaphragm and a negative pole piece which are arranged in sequence, the positive pole piece is provided with a positive empty foil section in an extending manner, the negative pole piece is provided with a negative empty foil section, and the positive empty foil section and the negative empty foil section are used for charging and discharging the battery cell structure; the positive pole piece is also provided with a first empty foil area or the negative pole piece is also provided with a second empty foil area; the first empty foil area and the second empty foil area are also used for charging and discharging the cell structure; therefore, the technical defect that the charge-discharge capacity of the battery cell is invalid or weakened after the empty foil sections of the positive and negative electrodes in the existing battery cell structure are broken is overcome; in addition, the invention further designs a laminated battery, and the anti-falling capability of the laminated battery is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of secondary batteries, and specifically relates to a battery cell structure and a laminated battery. Background Art

[0002] With the rapid development of industries such as electric vehicles and new energy storage, battery technology has gradually become an important support for energy storage and conversion. As a mainstream structure of lithium-ion batteries, laminated batteries are widely used in various battery products due to their advantages such as high energy density, long life, and low internal resistance. In particular, L-type laminated batteries are widely used in many fields. L-type laminated batteries can effectively improve the energy density and overall battery performance of the battery cell by stacking the positive electrode sheet, the negative electrode sheet, and the separator.

[0003] In the existing laminated battery, in the electrode welding process, the empty foil area of ​​each layer of the electrode needs to be connected together by welding or welded together with the pole ear component to achieve the input and output of current. However, due to the welding process and the possible drop, extrusion and other situations that may occur during actual use, the empty foil area is prone to breakage during welding and drop folding, especially at the part connected to the pole ear. Once the empty foil area breaks, it will directly cause the corresponding layer of the electrode to lose its charging and discharging ability, seriously affecting the overall performance of the battery cell.

[0004] Based on this, it is urgent to improve the existing battery cell structure and laminated battery to solve the defects of the aforementioned technology. Summary of the invention

[0005] One of the purposes of the present invention is to address the deficiencies of the prior art and provide a battery cell structure in which the pole piece can still be charged and discharged after the empty foil area of ​​the pole piece is broken.

[0006] In order to achieve the above-mentioned invention objectives, this application implements the following technical solutions:

[0007] A battery cell structure comprises a positive electrode sheet, a separator and a negative electrode sheet arranged in sequence, wherein the positive electrode sheet is extended with a positive electrode empty foil segment, and the negative electrode sheet is provided with a negative electrode empty foil segment, and the positive electrode empty foil segment and the negative electrode empty foil segment are used for charging and discharging the battery cell structure; the positive electrode sheet is also provided with a first empty foil area or the negative electrode sheet is also provided with a second empty foil area, and the first empty foil area and the second empty foil area are also used for charging and discharging the battery cell structure.

[0008] The above technical solution produces the following technical effects:

[0009] In view of the problem of tab breakage in existing battery cells, the present application proposes a new battery cell structure design, which allows the battery cell to still perform charge and discharge after the positive and negative electrode empty foil segments are broken by setting the first empty foil area and the second empty foil area on the positive and negative electrode sheets. Specifically, the present application forms multiple welding points by adding empty foil areas on each layer of the electrode sheet, and avoids the technical defect of the battery cell failing due to the positive and negative electrode empty foil segments by reasonably arranging the welding structure. At the same time, by adding a new set of welding structures (i.e., the first empty foil area and the second empty foil area), the temperature rise and resistance inside the battery cell are effectively reduced and the safety of the battery cell is significantly improved.

[0010] As a further improvement to a battery core structure of the present invention, the positive electrode sheet includes a first bent portion and two first main body portions transitionally connected by the first bent portion;

[0011] The negative electrode sheet includes a second bending portion and two second main bodies connected by transition through the second bending portion;

[0012] The diaphragm includes a third bending portion and two third main body portions transitionally connected through the third bending portion.

[0013] As a further improvement to a battery core structure of the present invention, the first empty foil area is arranged at the first bending portion, and the second empty foil area is arranged at the second bending portion.

[0014] As a further improvement to a battery cell structure of the present invention, when the positive electrode plate is provided with a first empty foil area, the negative electrode plate is provided with a first notch corresponding to the first empty foil area, and the diaphragm is provided with a second notch corresponding to the first empty foil area.

[0015] As a further improvement to a battery cell structure of the present invention, when the negative electrode plate is provided with a second empty foil area, the positive electrode plate is provided with a third notch corresponding to the second empty foil area, and the diaphragm is provided with a second notch corresponding to the second empty foil area.

[0016] The second purpose of the present invention is to provide a laminated battery to address the deficiencies in the prior art and to solve the technical defect that the internal charging and discharging capacity of the existing laminated battery fails or is weakened after falling.

[0017] In order to achieve the above-mentioned invention objectives, this application implements the following technical solutions:

[0018] A laminated battery cell, comprising any of the above battery cell structures, including at least two battery cell structures comprising a first empty foil region and / or at least two battery cell structures comprising a second empty foil region;

[0019] The first empty foil area and the adjacent first empty foil area are welded to form a first connection body; the second empty foil area and the adjacent second empty foil area are welded to form a second connection body.

[0020] The above technical solution produces the following technical effects:

[0021] The laminated battery of the present application is provided with a first connector and a second connector. When the laminated battery is impacted by external force, stress can be dispersed through multiple welding points, thereby improving the impact resistance of the battery. At the same time, due to the increase in welding points, the current path inside the battery is more diversified. Even if some welding points are broken, the battery can still maintain the charging and discharging function through other welding points. In addition, the above technical solution also effectively reduces the temperature rise inside the battery and improves the thermal stability of the battery by optimizing the welding structure.

[0022] As a further improvement to the laminated battery core of the present invention, the laminated battery core further comprises a packaging film, and the packaging film is used for assembling the laminated battery core.

[0023] As a further improvement to the laminated battery core of the present invention, the first connector and the second connector are provided with cutting areas.

[0024] As a further improvement to a laminated battery cell of the present invention, when the laminated battery cell is only provided with a first connector, the two side surfaces of the first connector along the thickness direction are coated with hot melt adhesive; when the laminated battery cell is only provided with a second connector, the two side surfaces of the second connector along the thickness direction are coated with hot melt adhesive.

[0025] As a further improvement to a laminated battery core of the present invention, when the laminated battery core includes both a first connector and a second connector, a surface of the first connector or the second connector closest to the packaging film along the thickness direction of the laminated battery core is coated with hot melt adhesive. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 This is one of the schematic diagrams of the battery cell structure in Example 1 of the present invention;

[0028] Figure 2 This is one of the schematic diagrams of the structure of the positive electrode sheet in Example 1 of the present invention;

[0029] Figure 3 This is one of the schematic diagrams of the structure of the negative electrode sheet in Example 1 of the present invention;

[0030] Figure 4 This is a schematic diagram of the diaphragm structure in Example 1 of the present invention;

[0031] Figure 5 This is the second schematic diagram of the battery cell structure in Example 1 of the present invention;

[0032] Figure 6 This is the second schematic diagram of the structure of the negative electrode sheet in Example 1 of the present invention;

[0033] Figure 7 This is the second schematic diagram of the positive electrode structure in Example 1 of the present invention;

[0034] Figure 8 This is one of the schematic diagrams of the laminated battery structure in Example 3 of the present invention;

[0035] Fig. 9 This is the second schematic diagram of the laminated battery structure in Example 3 of the present invention;

[0036] Fig.10 for Fig. 9 Section along A-A;

[0037] in:

[0038] 1-cell structure;

[0039] 11- positive electrode;

[0040] 111-positive electrode empty foil segment;

[0041] 112 - first empty foil area;

[0042] 113 - first bending portion;

[0043] 114-The first body part;

[0044] 115 – Third gap;

[0045] 12 - diaphragm;

[0046] 121 - third bending portion;

[0047] 122 - third body part;

[0048] 123 - second gap;

[0049] 13 - negative electrode;

[0050] 131 - negative electrode empty foil segment;

[0051] 132 - second empty foil area;

[0052] 133 - second bending portion;

[0053] 134 - second body part;

[0054] 135 – First gap;

[0055] 2-first connector;

[0056] 21 - cutting area;

[0057] 3-second connector;

[0058] 4-Packaging film;

[0059] 5-Hot melt adhesive. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0061] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] Although the present application is disclosed as above in the form of a preferred embodiment, it is not intended to limit the claims. Any person skilled in the art may make several possible changes and modifications without departing from the concept of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

[0063] The present invention is further described in detail below in conjunction with specific implementation modes, but the implementation modes of the present invention are not limited thereto.

[0064] Example 1

[0065] like Figure 1-7, in order to solve the problem of battery charging and discharging function being damaged due to falling in the prior art, the present invention improves the stacked battery cell structure 1 in the battery. Specifically, the battery cell structure 1 in the present application includes a positive electrode sheet 11, a diaphragm 12, and a negative electrode sheet 13 arranged in sequence, the positive electrode sheet 11 is extended with a positive electrode empty foil segment 111, and the negative electrode sheet 13 is provided with a negative electrode empty foil segment, and the positive electrode empty foil segment 111 and the negative electrode empty foil segment are used for charging and discharging the battery cell structure 1; the positive electrode sheet 11 is also provided with a first empty foil area 112 or the negative electrode sheet 13 is also provided with a second empty foil area 132, and the first empty foil area 112 and the second empty foil area 132 are also used for charging and discharging the battery cell structure 1.

[0066] Specifically, by providing the first empty foil area 112 on the positive electrode sheet 11 and the second empty foil area 132 on the negative electrode sheet 13, the current path inside the battery can be increased, so that even if some welding points of the battery are broken, the normal charging and discharging function can still be maintained through other welding points. This design significantly improves the impact resistance and reliability of the battery, ensuring the stable operation of the battery under harsh conditions. In addition, when the first empty foil area 112 domain and the first empty foil area 112 domain / the second empty foil area 132 domain and the second empty foil area 132 domain are welded to form an additional welding structure, when the battery is impacted by external force, the stress can be dispersed by multiple welding points, thereby effectively protecting the internal structure of the battery from damage.

[0067] It is worth noting that the above technical solution of the present application includes two cases: a battery cell structure 1 having a positive electrode sheet 11 with a first empty foil area 112 and a battery cell structure 1 having a negative electrode sheet 13 with a second empty foil area 132. In the specific implementation process, the laminated battery prepared by the battery cell structure 1 of the present application can be formed by stacking a plurality of battery cell structures 1 including a positive electrode sheet 11 with a first empty foil area 112 or by stacking a plurality of battery cell structures 1 including a negative electrode sheet 13 with a second empty foil area 132; in addition, the laminated battery prepared by the battery cell structure 1 of the present application can also be formed by stacking a plurality of battery cell structures 1 including a positive electrode sheet 11 with a first empty foil area 112 and a plurality of battery cell structures 1 including a negative electrode sheet 13 with a second empty foil area 132.

[0068] Specifically, the present application not only enhances the mechanical strength of the battery by setting additional welding points (the first empty foil area 112 and the second empty foil area 132) in the battery cell structure 1, but also reduces the local overheating caused by current concentration by dispersing the current path, thereby effectively reducing the temperature rise inside the battery and improving the thermal stability of the battery.

[0069] In summary, the present invention not only improves the impact resistance and reliability of the battery, but also effectively reduces the temperature rise inside the battery and improves the thermal stability of the battery by setting an additional empty foil area in the battery core structure 1 and optimizing the welding structure.

[0070] Example 2

[0071] like Figure 1 -7, which is different from Example 1: in order to further reduce the influence of the first empty foil area 112 and the second empty foil area 132 on the size of the battery cell structure 1, further, the positive electrode plate 11 includes a first bending portion 113 and two first main body portions 114 transitionally connected by the first bending portion 113; the negative electrode plate 13 includes a second bending portion 133 and two second main body portions 134 transitionally connected by the second bending portion 133; the diaphragm 12 includes a third bending portion 121 and two third main body portions 122 transitionally connected by the third bending portion 121.

[0072] Specifically, the positive electrode sheet 11 realizes an L-shaped structure through the first bending portion 113 and the first main body portion 114, the negative electrode sheet 13 realizes an L-shaped structure through the second bending portion 133 and the second main body portion 134, and the diaphragm 12 realizes an L-shaped structure through the third bending portion 121 and the third main body portion 122. This design enables the battery cell structure 1 to adapt to a more compact spatial layout while maintaining the original function, thereby achieving a higher energy density without increasing the overall size of the battery. Furthermore, the battery cell of the present application is designed with an L-shaped structure, and when the battery cell structure 1 is impacted by an external force, the bending portion can play a buffering role, reducing the damage to the internal structure of the battery cell caused by the direct impact. At the same time, due to the presence of the bending portion, the battery cell structure 1 can be more compact when stacked, further improving the volume utilization of the battery, which is of great significance for improving the energy density of the battery.

[0073] Further, the first empty foil area 112 is arranged at the first bending portion 113, and the second empty foil area 132 is arranged at the second bending portion 133. At the same time, as shown in the figure, the first empty foil area 112 and the second empty foil area 132 are both arc-shaped and arranged on the inner side of the first bending portion 113 and the second bending portion 133. Thus, in the manufacturing process of the battery cell, the arc-shaped design of the first empty foil area 112 and the second empty foil area 132 allows the reasonable layout of the welding points, thereby avoiding the stress concentration of the welding points on the internal structure of the battery cell. This layout method ensures that the welding points will not have a negative impact on the performance of the battery cell, while maintaining the structural strength and stability of the battery cell. In addition, since the welding points are located on the inner side of the bending portion, they will not increase the thickness of the battery cell, and therefore will not affect the volume utilization of the battery. Further implementation of the above-mentioned improvement of the battery cell structure 1 of the present application will not cause the influence of the thickness of the laminated battery prepared according to the above-mentioned battery cell structure 1 and the influence of the battery capacity due to the additional welding points (the first empty foil area 112 and the second empty foil area 132).

[0074] Furthermore, when the positive electrode sheet 11 is provided with a first empty foil area 112, the negative electrode sheet 13 is provided with a first notch 135 corresponding to the first empty foil area 112, and the diaphragm 12 is provided with a second notch 123 corresponding to the first empty foil area 112. With this design, the first empty foil area 112 is welded to the first empty foil area 112 of the positive electrode sheet 11 of the adjacent battery cell structure 1 through the first notch 135 and the second notch 123. In addition, when the battery cell structure 1 of the present application is impacted by an external force, the first notch 135 and the second notch 123 can be used as stress release areas, allowing the battery cell to deform to a certain extent without affecting the integrity of the overall structure. This design not only improves the mechanical strength of the battery, but also enhances the safety performance of the battery in harsh environments. At the same time, the notch design also makes the battery cells more flexible when stacking, adapting to different spatial layouts, and further optimizing the volume utilization of the battery.

[0075] Further, when the negative electrode sheet 13 is provided with a second empty foil area 132, the positive electrode sheet 11 is provided with a third notch 115 corresponding to the second empty foil area 132, and the diaphragm 12 is provided with a second notch 123 corresponding to the second empty foil area 132. Through the above design, the second empty foil area 132 and the second empty foil area 132 of the negative electrode sheet 13 of the adjacent battery cell structure 1 are welded through the third notch 115 and the second notch 123. This design also allows the battery cell to release stress through the notch when it is impacted by external force, thereby protecting the battery cell structure 1 from damage. At the same time, the presence of the notch also makes the battery cell more adaptable when stacked, and can be adjusted according to different space requirements, further improving the volume utilization of the battery.

[0076] In summary, the present invention not only improves the impact resistance and safety of the battery, but also optimizes the volume utilization of the battery, thereby not increasing the overall size of the battery, by introducing the bending portion and the notch design in the battery structure 1. In addition, when the battery is impacted by an external force, the arc shape of the bending portion can effectively disperse the stress and reduce the stress concentration, thereby protecting the battery structure 1 from damage. In addition, due to the arc shape design of the first empty foil area 112 and the second empty foil area 132, they can form a more uniform and stable welding point during welding, further improving the reliability and safety of the battery.

[0077] The rest of the details that are the same as those in Implementation 1 are not described in detail in this implementation.

[0078] Example 3

[0079] like Figure 1-10, which is different from Example 1: In order to mitigate the change in the charging and discharging performance of the existing laminated battery after being subjected to external force, specifically, the present application also designs a laminated battery cell, which includes any of the above-mentioned battery cell structures 1, including at least two battery cell structures 1 including a first empty foil area 112 and / or at least two battery cell structures 1 including a second empty foil area 132; wherein the first empty foil area 112 is welded to the adjacent first empty foil area 112 to form a first connector 2; the second empty foil area 132 is welded to the adjacent second empty foil area 132 to form a second connector 3.

[0080] Specifically, the design of the first connector 2 and the second connector 3 enables the laminated battery core to disperse stress through multiple welding points when subjected to external force impact, thereby improving the impact resistance of the battery. At the same time, due to the increase in welding points, the current path inside the battery is more diversified. Even if the welds at the tabs are broken when subjected to external force, the battery can still maintain the charge and discharge function through other welding points. In addition, the laminated battery core of the present application effectively reduces the temperature rise inside the battery and improves the thermal stability of the battery by optimizing the welding structure. This design not only ensures the stable operation of the battery under harsh conditions, but also improves the safety performance of the battery and reduces the potential safety hazards caused by excessive temperature.

[0081] Furthermore, the laminated battery cell also includes a packaging film 4, which is used to assemble the laminated battery cell. In the specific embodiment of the present application, the packaging film 4 is an aluminum-plastic film structure. The packaging film 4 of the aluminum-plastic film structure can not only provide good sealing performance to prevent the leakage of chemical substances inside the battery, but also provide certain mechanical protection to reduce the damage to the battery by the external environment. In addition, the use of the aluminum-plastic film also makes the battery have better heat resistance and corrosion resistance, thereby extending the service life of the battery.

[0082] Furthermore, the first connector 2 and the second connector 3 are provided with a cutting area 21. Figure 8 The design does not have a cutting area 21, but it does not mean that the structure will not be cut later. Figure 8 Taking the first connector 2 as an example, the welding method is electric welding; Fig. 9 Taking the second connector 3 as an example, the welding method is regional welding, but it does not mean that the technical solution of this application is limited to Figure 8 , Fig. 9 shown.

[0083] Specifically, the cutting area 21 is designed to facilitate cutting and separation of the laminated cells during the production process to meet the needs of battery packs of different sizes and shapes. The setting of the cutting area 21 allows the laminated cells to have higher flexibility during the manufacturing and assembly process, while ensuring the structural integrity and electrical performance stability of the battery pack. In the specific implementation process, the aluminum-plastic film also has the situation of setting the cutting area 21, that is, the laminated cells are cut after the aluminum-plastic film is wrapped with the laminated cells that have not been cut.

[0084] Furthermore, when the laminated battery core is provided with only the first connector 2, the two sides of the first connector 2 along the thickness direction (Y-axis direction) are coated with hot melt adhesive 5; when the laminated battery core is provided with only the second connector 3, the two sides of the second connector 3 along the thickness direction (Y-axis direction) are coated with hot melt adhesive 5. Thus, the use of the hot melt adhesive 5 ensures the stability and sealing of the first connector 2 and the second connector 3 inside the battery, prevents the leakage of chemical substances inside the battery, and provides additional mechanical protection, further enhancing the impact resistance of the battery.

[0085] Furthermore, when the laminated battery cell includes both the first connector 2 and the second connector 3, the surface of the first connector 2 or the second connector 3 closest to the packaging film 4 is coated with hot melt adhesive 5 along the thickness direction (Y-axis direction) of the laminated battery cell. This design not only strengthens the bonding force between the battery cell and the packaging film 4, but also improves the overall structural stability of the battery, ensuring the safety and reliability of the battery in harsh environments. It is worth noting that the above only represents different stacking methods of the present application, but the present application does not limit the number or arrangement of the first connector 2 and the second connector 3 of each battery cell in the laminated battery.

[0086] The rest of the details that are the same as those in Implementation 1 are not described in detail in this implementation.

[0087] The above are only preferred implementations of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell structure, characterized in that: The invention comprises a positive electrode sheet (11), a separator (12), and a negative electrode sheet (13) which are arranged in sequence, and is characterized in that the positive electrode sheet (11) is extended with a positive electrode empty foil segment (111), and the negative electrode sheet (13) is provided with a negative electrode empty foil segment (131), and the positive electrode empty foil segment (111) and the negative electrode empty foil segment (131) are used for charging and discharging the battery cell structure; The positive electrode plate (11) is further provided with a first empty foil area (112) or the negative electrode plate (13) is further provided with a second empty foil area (132), and the first empty foil area (112) and the second empty foil area (132) are also used for charging and discharging the battery cell structure.

2. A battery core structure according to claim 1, characterized in that: The positive electrode sheet (11) comprises a first bent portion (113) and two first main body portions (114) transitionally connected via the first bent portion (113); The negative electrode plate (13) comprises a second bent portion (133) and two second main body portions (134) transitionally connected via the second bent portion (133); The diaphragm (12) comprises a third bent portion (121) and two third main body portions (122) transitionally connected via the third bent portion (121).

3. A battery core structure according to claim 2, characterized in that: The first empty foil area (112) is arranged at the first bending portion (113), and the second empty foil area (132) is arranged at the second bending portion (133).

4. A battery core structure according to claim 1, characterized in that: When the positive electrode plate (11) is provided with a first empty foil area (112), the negative electrode plate (13) is provided with a first notch (135) corresponding to the first empty foil area (112), and the diaphragm (12) is provided with a second notch (123) corresponding to the first empty foil area (112).

5. A battery cell structure according to claim 1, characterized in that: When the negative electrode plate (13) is provided with a second empty foil area (132), the positive electrode plate (11) is provided with a third notch (115) corresponding to the second empty foil area (132), and the diaphragm (12) is provided with a second notch (123) corresponding to the second empty foil area (132).

6. A laminated battery, comprising the battery cell structure according to any one of claims 1 to 5, characterized in that: Comprising at least two battery core structures comprising a first empty foil region (112) and / or at least two battery core structures comprising a second empty foil region (132); The first empty foil area (112) and the adjacent first empty foil area (112) are welded to form a first connection body (2); and the second empty foil area (132) and the adjacent second empty foil area (132) are welded to form a second connection body (3).

7. A laminated battery according to claim 6, characterized in that: It also comprises a packaging film (4), wherein the packaging film (4) is used for assembling the laminated battery.

8. The laminated battery according to claim 6, characterized in that: The first connector (2) and the second connector (3) are provided with a cutting area (21).

9. The laminated battery according to claim 7, characterized in that: When the laminated battery is provided with only a first connector (2), the two side surfaces of the first connector (2) along the thickness direction are coated with hot melt adhesive (5); when the laminated battery is provided with only a second connector (3), the two side surfaces of the second connector (3) along the thickness direction are coated with hot melt adhesive (5).

10. The laminated battery according to claim 7, characterized in that: When the laminated battery comprises both a first connector (2) and a second connector (3), a hot melt adhesive (5) is applied to the surface of the first connector (2) or the second connector (2) closest to the packaging film (4) along the thickness direction of the laminated battery.

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