Secondary battery and battery pack

Abstract

The utility model discloses a secondary battery and a battery pack. According to the secondary battery, a first insulating part is arranged, the first insulating part comprises a first adhesive part, a first non-adhesive part and a second adhesive part, the first non-adhesive part is arranged between the first adhesive part and the second adhesive part, the first adhesive part is in adhesive connection with a first side wall of a main body part, and the second adhesive part is in adhesive connection with one surface, deviating from a first section of a tab bundle, of an adapter piece; at least part of one surface, facing the first insulating part, of the second section of the tab bundle is covered by the first non-adhesive part, and the first non-adhesive part is arranged to form isolation and separation between the first adhesive part and the second adhesive part, so that the connection stability between the first insulating part and the electrode assembly is ensured; and the length of the first non-adhesive part is limited to meet the requirement that the pulling force of the first adhesive part to the second adhesive part is reduced when the first adhesive part moves, so that the tearing risk of the first insulating part to the switching piece is reduced or even eliminated, and the use safety of the secondary battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and particularly relates to a secondary battery and a battery pack. Background Art

[0002] During the manufacturing process of secondary batteries, after the ear bundle is welded to the adapter plate, adhesive tapes need to be attached to the opposite two sides in the thickness direction of the ear bundle to play an insulating role. However, during the cyclic use of secondary batteries, the main body of the electrode assembly will expand and move. During the expansion and movement of the main body, the adhesive tape will be driven to move. The movement of the adhesive tape will generate a pulling force on the adapter plate to which it is attached, resulting in a risk of tearing of the adapter plate and affecting the use safety of the secondary battery. Summary of the Utility Model

[0003] The purpose of the utility model is to provide a secondary battery and a battery pack to solve the problem that the adhesive tape in the current secondary battery easily causes a risk of tearing of the ear, thus affecting the use safety of the secondary battery.

[0004] A first aspect of an embodiment of the present application provides a secondary battery, including: an electrode assembly, the electrode assembly includes a main body portion and an ear bundle connected to the main body portion, the main body portion has an intersecting first direction and second direction, the main body portion has a first end face intersecting with the first direction and a first side wall intersecting with the second direction, the ear bundle includes a connected first section and a second section, the second section is connected to the main body portion at the first end face, and the first section is located at an end of the second section away from the main body portion; an adapter plate, the adapter plate is stacked with the first section along the thickness direction of the first section, and the adapter plate is connected to the first section; a first insulating member, including a first adhesive portion, a first non-adhesive portion, and a second adhesive portion, the first non-adhesive portion is disposed between the first adhesive portion and the second adhesive portion, the first adhesive portion is adhesively connected to the first side wall, the second adhesive portion is adhesively connected to a surface of the adapter plate facing away from the first section, and at least a part of a surface of the second section facing the first insulating member is covered by the first non-adhesive portion; the distance between the plane where the surface of the adapter plate facing away from the first section is located and the plane where the first end face is located in the first direction is F mm, 3.5 mm ≤ F ≤ 5.5 mm; along the length direction of the adapter plate, the distance between the plane where the end face of the adapter plate adjacent to the first side wall is located and the plane where the adjacent first side wall is located in the second direction is G mm, 1 mm ≤ G ≤ 2 mm; in the flattened state of the first insulating member, along the length direction of the first insulating member, the length of the first non-adhesive portion is L 11 mm, satisfying: S is the margin, 2 mm ≤ S ≤ 10 mm.

[0005] A second aspect of an embodiment of the present application provides a battery pack, comprising the secondary battery as described above.

[0006] In summary, the embodiments of the present application provide a secondary battery and a battery pack having the secondary battery, wherein the secondary battery is provided with a first insulating member, the first insulating member includes a first adhesive portion, a first non-adhesive portion and a second adhesive portion, the first non-adhesive portion is provided between the first adhesive portion and the second adhesive portion, the first adhesive portion is adhesively connected to the second wall of the main body of the electrode assembly, the second adhesive portion is adhesively connected to a side of the adapter sheet away from the first section of the tab bundle, so as to ensure the connection stability between the first insulating member and the electrode assembly and avoid falling off, at least a portion of the second section of the tab bundle facing the first insulating member in the thickness direction thereof is covered by the first non-adhesive portion, the provision of the first non-adhesive portion forms isolation and separation between the first adhesive portion and the second adhesive portion, and limits the length of the first non-adhesive portion to meet Therefore, when the main body expands or moves and causes the first adhesive part to move, the pulling force of the first adhesive part on the second adhesive part is reduced, thereby reducing or even eliminating the risk of the first insulating member tearing the adapter, thereby improving the safety and service life of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following briefly introduces the drawings required for describing the embodiments.

[0008] Figure 1 is a schematic structural diagram of a secondary battery provided in an embodiment of the present application;

[0009] Figure 2 It is a schematic diagram of the combined structure of two electrode assemblies, a first insulating member, a second insulating member, and a switching plate in a secondary battery provided by an embodiment of the present application in a second state;

[0010] Figure 3 yes Figure 2 A1 of the enlarged structural diagram;

[0011] Figure 4 It is a schematic diagram of the combined structure of two electrode assemblies, a first insulating member, a second insulating member, and a switching plate in a secondary battery provided by an embodiment of the present application in a first state;

[0012] Figure 5 yes Figure 4 A2 of the enlarged structural diagram;

[0013] Figure 6 yes Figure 4 A top view of

[0014] Figure 7 yes Figure 6 A3 of the enlarged structural diagram;

[0015] Figure 8 It is a schematic diagram of the combined structure of the electrode assembly, the first insulating member, the second insulating member, the connecting piece, and the third insulating member in the secondary battery provided by the embodiment of the present application in the first state;

[0016] Figure 9 It is a first schematic diagram of the first insulating member in the secondary battery provided by the embodiment of the present application;

[0017] Figure 10 It is a second schematic diagram of the first insulating member in the secondary battery provided by the embodiment of the present application;

[0018] Figure 11 It is a schematic diagram of the second insulating member in the secondary battery provided by the embodiment of the present application;

[0019] Figure 12 It is a schematic diagram of the combined structure of a single electrode assembly, the first insulating member, the second insulating member, and the connecting piece in the secondary battery provided by the embodiment of the present application in the first state;

[0020] Figure 13 is Figure 12 a schematic diagram of the first insulating member shown;

[0021] Figure 14 is Figure 12 a schematic diagram of the second insulating member shown.

[0022] Main reference numeral description:

[0023] 1. Secondary battery;

[0024] 10. Electrode assembly, 101. First electrode assembly, 102. Second electrode assembly, 11. Main body portion, 111. First end face, 112. First side wall, 113. Second side wall, 114. Second end face, 115. Third side wall, 116. Fourth side wall, 12. Tab bundle, 12a. Positive tab bundle, 12b. Negative tab bundle, 121. First segment, 1211. First face, 1212. Second face, 122. Second segment, 123. Welding mark, 1231. Third end face, 1232. Fourth end face;

[0025] 20. Connecting piece, 201. First side face, 202. Second side face;

[0026] 30. First insulating member, 31. First adhesive portion, 32. First non - adhesive portion, 33. Second adhesive portion;

[0027] 40. Second insulating member, 41. Third adhesive portion, 42. Second non - adhesive portion, 43. Fourth adhesive portion;

[0028] 50. Terminal, 51. Top cover plate, 60. Third insulating member, 70. Housing, 701. Accommodating cavity.

[0029] X. First direction, Y. Second direction, Z. Third direction. Detailed implementation manner

[0030] In order to make the purpose, technical solution and beneficial effects of the present application clearer, the following further details the present application in combination with the accompanying drawings and specific implementation manners. It should be understood that the specific implementation manners described in this specification are only for explaining the present application and not for limiting the present application.

[0031] This embodiment provides a battery pack, including a secondary battery 1.

[0032] In some embodiments of the present application, a secondary battery 1 is provided. Refer to Figures 1 - 5 , Figures 8 - 10 and Figures 12 - 13 , the secondary battery 1 includes: an electrode assembly 10, a connecting piece 20 and a first insulating member 30.

[0033] Refer to Figures 1 - 6 , Figure 8 and Figure 12 , the electrode assembly 10 includes a main body portion 11 and a tab bundle 12 connected to the main body portion 11. The main body portion 11 has a first direction X, a second direction Y and a third direction Z that intersect pairwise. Specifically, in the embodiments shown in Figures 1 - 6 , Figure 8 and Figure 12 , the first direction X, the second direction Y and the third direction Z are pairwise orthogonal. The first direction X is the height direction of the main body portion 11, the second direction Y is the thickness direction of the main body portion 11, and the third direction Z is the length direction of the main body portion 11. Refer to Figures 1 - 6 , Figure 8 and Figure 12 , the main body portion 11 has a first end face 111 that intersects with the first direction X. Refer to Figures 1 - 4 , Figure 8 and Figure 12 , the main body portion 11 further has a first side wall 112 that intersects with the second direction Y. Refer to Figures 1 - 4 , Figure 6 , Figure 8 and Figure 12 , the main body portion 11 further has a second side wall 113. The second side wall 113 is disposed opposite to the first side wall 112 along the second direction Y. Refer to Figures 1 - 2 and Figure 6 , the main body portion 11 further has a second end face 114. The second end face 114 is disposed opposite to the first end face 111 along the first direction X. Refer to Figure 6, the main body 11 further has a third side wall 115 and a fourth side wall 116 that are oppositely arranged along the third direction Z, and the surface areas of the first side wall 112 and the second side wall 113 are larger than the surface areas of the third side wall 115 and the fourth side wall 116.

[0034] Refer to Figures 1 - 6 and Figure 8 and Figure 12 , the tab bundle 12 includes a connected first section 121 and a second section 122, and the second section 122 is connected to the main body 11 at the first end face 111. Specifically, the main body 11 includes a positive electrode sheet, a separator, and a negative electrode sheet. The positive electrode sheet, the separator, and the negative electrode sheet are stacked to form a stacked electrode assembly, or, after the positive electrode sheet, the separator, and the negative electrode sheet are stacked, they are wound to form a wound electrode assembly. Refer to Figure 6 , the tab bundle 12 includes a positive tab bundle 12a and a negative tab bundle 12b. The positive tab bundle 12a includes multiple positive tab sheets, and the negative tab bundle 12b includes multiple negative tab bundles. The positive tab bundle 12a is connected to the wound or stacked positive electrode sheet, and the negative tab bundle 12b is connected to the wound or stacked negative electrode sheet. In other words, the positive tab sheet is formed by cutting the portion of the positive electrode sheet where the positive active material layer is not coated, or the positive tab sheet is welded to the portion of the positive electrode sheet where the positive active material layer is not coated. The negative tab sheet is formed by cutting the portion of the negative electrode sheet where the negative active material layer is not coated, or the negative tab sheet is welded to the portion of the negative electrode sheet where the negative active material layer is not coated. Due to the differences in the lengths of the positive electrode sheet, the separator, and the negative electrode sheet in the main body 11, the first end face 111 of the main body 11 is the end face where the positive electrode sheet is connected to the positive tab bundle 12a, or, the first end face 111 of the main body 11 is the end face where the negative electrode sheet is connected to the negative tab bundle 12b.

[0035] Refer to Figures 1 - 8 and Figure 12 , the adapter plate 20 is stacked with the first section 121 of the tab bundle 12 along the thickness direction of the first section 121. The adapter plate 20 is connected to the first section 121. The adapter plate 20 is used to connect the tab bundle 12 to the terminal of the secondary battery 1, so as to transfer the electric energy generated during the cycling of the electrode assembly 10.

[0036] Refer to Figures 1 - 5 , Figures 8 - 10 and Figures 12 - 13, the first insulating member 30 includes a first adhesive portion 31, a first non - adhesive portion 32, and a second adhesive portion 33. The portions of the first adhesive portion 31 and the second adhesive portion 33 having an adhesive function are arranged on the same side. When the first insulating member 30 is in a flattened state, along the length direction of the first insulating member 30, the first non - adhesive portion 32 is disposed between the first adhesive portion 31 and the second adhesive portion 33. The first adhesive portion 31 is adhesively connected to the first side wall 112 of the main body portion 11, and the second adhesive portion 33 is adhesively connected to the surface of the adapter piece 20 facing away from the first section 121. At least a part of the surface of the second section 122 of the tab bundle 12 facing the first insulating member 30 is covered by the first non - adhesive portion 32. Specifically, as shown in Figures 1 - 5 , Figures 8 - 10 and Figures 12 - 13 in the illustrated embodiment, the entire surface of the second section 122 facing the first insulating member 30 is covered by the first non - adhesive portion 32. In other words, the orthographic projection of the second section 122 on the plane where the first side wall 112 is located falls within the orthographic projection of the first non - adhesive portion 32 on the plane where the first side wall 112 is located.

[0037] Referring to Figures 1 - 3 , along the first direction X, the distance between the plane of the surface of the adapter piece 20 facing away from the first section 121 of the tab bundle 12 and the plane of the first end face 111 of the main body portion 11 is F mm, where 3.5 mm ≤ F ≤ 5.5 mm. Specifically, the value of F can be any value among 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm or any value within the range formed by any two of these values. Along the length direction of the adapter piece 20, the distance between the plane of the end face of the end of the adapter piece 20 adjacent to the first side wall 112 of the main body portion 11 and the plane of the first side wall 112 adjacent to the adapter piece 20 in the second direction Y is G mm, where 1 mm ≤ G ≤ 2 mm. Specifically, the value of G can be any value among 1 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.7 mm, 1.9 mm, 2 mm or any value within the range formed by any two of these values. Referring to Figure 13 , when the first insulating member 30 is in a flattened state, the length of the first non - adhesive portion 32 is L 11 mm; satisfying: S is the margin, 2 mm ≤ S ≤ 10 mm.

[0038] During the manufacturing process of a secondary battery, after the tab bundle is welded to the adapter plate, it is necessary to attach adhesive tape to the side of the adapter plate facing away from the tab bundle to play an insulating role and prevent the adapter plate from contacting the main body part and causing a short circuit. However, during the cyclic use of the secondary battery, the main body part of the electrode assembly will expand and move. During the expansion and movement of the main body part, it will pull on the adhesive tape attached to the main body part. The pulling force of the main body part on the adhesive tape is transmitted to the adapter plate through the adhesive tape, generating a pulling force on the adapter plate to which the adhesive tape is attached. Moreover, the adapter plate is usually welded to the tab bundle, and the welding part is relatively weak. The existence of the pulling force of the adhesive tape makes the welding position between the adapter plate and the tab bundle prone to tearing risk, affecting the use safety and service life of the secondary battery.

[0039] However, for the secondary battery 1 provided by the embodiment of the present application, by providing the first insulating member 30, the first insulating member 30 includes a first adhesive part 31, a first non - adhesive part 32, and a second adhesive part 33. The first non - adhesive part 32 is disposed between the first adhesive part 31 and the second adhesive part 33. The first adhesive part 31 is adhesively connected to the first side wall 112 of the main body part 11, and the second adhesive part 33 is adhesively connected to one side of the first section 121 of the adapter plate 20 facing away from the tab bundle 12. At least a part of the second section 122 of the tab bundle 12 facing the first insulating member 30 is covered by the first non - adhesive part 32. The second adhesive part 33 is adhesively connected to the adapter plate 20, which can form an insulating coating for the adapter plate 20. The adhesive connection between the first adhesive part 31 and the first side wall 112 of the main body part 11 can ensure the connection stability between the first insulating member 30 and the main body part 11. The setting of the first non - adhesive part 32 between the first adhesive part 31 and the second adhesive part 33 can form an isolation and separation between the first adhesive part 31 and the second adhesive part 33, that is, the first adhesive part 31 and the second adhesive part 33 are not directly connected. When the main body part 11 of the electrode assembly 10 expands and / or shakes, driving the first adhesive part 31 to move and pulling on the first insulating member 30, the first non - adhesive part 32 can reduce the pulling force transmitted to the second adhesive part 33. The reason is that the first non - adhesive part 32 is not coated with an adhesive coating, thus cutting off the connection between the adhesive coating forming the first adhesive part 31 and the adhesive coating forming the second adhesive part 33, thereby reducing the pulling force of the first insulating member 30 on the connection between the adapter plate 20 and the first section 121, and further reducing or even eliminating the tearing risk of the first insulating member 30 at the connection between the adapter plate 20 and the first section 121, improving the use safety and service life of the secondary battery 1.

[0040] Moreover, referring to Figures 1 - 3 , the defined length value is the straight - line distance between the end face of the adapter plate 20 adjacent to one end of the first side wall 112 and the intersection of the first side wall 112 adjacent to the adapter plate 20 and the first end face 111 obtained according to the Pythagorean theorem. In other words, The defined length value is the shortest distance between the end face of the adapter piece 20 adjacent to one end of the first side wall 112 and the intersection of the first side wall 112 adjacent to the adapter piece 20 and the first end face 111. When L 11 has a value of , after the first insulating member 30 is adhesively connected to the first side wall 112 and the adapter piece 20, the first non-adhesive portion 32 is in a straightened and flat state. When L 11 has a value greater than , after the first insulating member 30 is adhesively connected to the first side wall 112 and the adapter piece 20, the first non-adhesive portion 32 can form an arc surface and a curved state. That is to say, when L 11 is within the range defined above, it can be ensured that the surface of the second section 122 of the tab bundle 12 facing the first insulating member 30 can be covered by the first non-adhesive portion 32, and the first insulating member 30 will not pull on both the first side wall 112 of the main body portion 11 and the adapter piece 20 due to the too short length of the first non-adhesive portion 32, resulting in a risk of tearing at the connection between the adapter piece 20 and the first section 121 of the tab bundle 12. Thus, it is possible to avoid the first adhesive portion 31 and the second adhesive portion 33 after pasting from pulling on the first non-adhesive portion 32, reduce the manufacturing cost of the first insulating member 30, ensure that the length of the first non-adhesive portion 32 covers the surface of the second section 122 facing the first insulating member 30, reduce the risk of tearing of the adapter piece 20 by the first insulating member 30 when the main body portion 11 expands or moves, and improve the service life of the secondary battery 1.

[0041] S is the allowance, 2 mm ≤ S ≤ 10 mm. The allowance S is the deviation allowance of the pasting device for attaching the first insulating member 30 to the first side wall 112 and the adapter piece 20. Specifically, the value of S can be any value among 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or any value in the range value composed of any two of these values. Since has a value less than F + G, limiting the range can further extend the length of the first non-adhesive portion 32, so that the first non-adhesive portion 32 has sufficient length and is applicable to electrode assemblies 10 of different models and different thicknesses, to reduce the risk of tearing of the adapter piece 20 by the first insulating member 30 when the main body portion 11 expands or moves, thereby reducing the defective rate of damaged tabs and improving the service life and use safety of the secondary battery 1.

[0042] Among them, the first adhesive portion 31 and the second adhesive portion 32 can be respectively formed by coating adhesive coatings at intervals on the same surface of the insulating film. The surface of the insulating film where the adhesive coating is not coated forms the first non-adhesive portion 32.

[0043] In some embodiments, referring to Figure 1, the secondary battery 1 further includes a terminal 50, a top cover plate 51, and a housing 70. An accommodation cavity 701 is provided inside the housing 70. The electrode assembly 10 and the adapter plate 20 are disposed in the accommodation cavity 701. The housing 70 has an opening adjacent to one end of the adapter plate 20 in the first direction X of the main body portion 11. The top cover plate 51 covers the opening to seal the accommodation cavity 701. The terminal 50 is inserted into the top cover plate 51, and one end of the terminal 50 extends into the accommodation cavity 701. Refer to Figure 6 , the end of the terminal 50 extending into the accommodation cavity 701 is welded to the adapter plate 20. Specifically, in the embodiment shown in Figure 6 , the terminal 50 is spaced apart from the second insulating member 60, and the terminal 50 is also spaced apart from the first insulating member 30. In some other implementation manners, a welding hole exposing the adapter plate 20 is formed on the surface of the first insulating member 30, and the terminal 50 is welded to the adapter plate 20 through the welding hole. Among them, the terminal 50 includes a positive terminal and a negative terminal. The positive terminal is connected to the positive electrode tab bundle 12a through the adapter plate 20, and the negative terminal is connected to the negative electrode tab bundle 12b through the adapter plate 20.

[0044] Among them, Figures 1 - 3 Figure shows the second state of the electrode assembly 10 after the secondary battery 1 is assembled. In the second state, the plane where the first side wall 112 of the main body portion 11 in the electrode assembly 10 is located intersects with the plane of the surface of the adapter plate 20 facing away from the first section 121 of the tab bundle 12. Specifically, in the embodiment shown in Figures 1 - 3 , in the second state, the plane where the first side wall 112 of the main body portion 11 in the electrode assembly 10 is located is orthogonal to the plane of the surface of the adapter plate 20 facing away from the first section 121 of the tab bundle 12. In the second state, the first section 121 of the tab bundle 12 is bent relative to the second section 122.

[0045] In some embodiments, refer to Figures 4 - 8 and Figure 12 , when the electrode assembly 20 is flattened, it has a first state in which the plane where the first side wall 112 is located can be parallel to the plane of the surface of the adapter plate 20 facing away from the first section 121 of the tab bundle 12. In other words, in the first state, the plane where the first side wall 112 of the main body portion 11 is located is parallel to the plane of the surface of the adapter plate 20 facing away from the first section 121 of the tab bundle 12. Refer to Figure 4 and Figure 5 , along the thickness direction of the first section 121 of the tab bundle 12, the first section 121 has a first surface 1211 and a second surface 1212 that are oppositely arranged, and the adapter plate 20 is connected to the second surface 1212 of the first section 121. Refer to Figure 4 and Figure 5 , in the first state, the distance between the plane of the surface of the adapter plate 20 facing away from the first section 121 and the first side wall 112 of the main body portion 11 in the second direction Y is D mm. Refer toFigure 4 and Figure 5 In the first state, along the first direction X, the adapter piece 20 has a first side surface 201 and a second side surface 202 which are oppositely arranged, and the distance between the first side surface 201 and the adjacent first end surface 111 is E mm; it satisfies that: S is the allowance, 2 mm ≤ S ≤ 10 mm. Specifically, the value of S can be any value among 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or any value within the range value composed of any two of these values. Among them, referring to Figures 4 - 5 , The length value defined is the straight-line distance between the first side surface 201 of the adapter piece 20 and the intersection of the adjacent first side wall 112 and the first end surface 111 obtained according to the Pythagorean theorem. In other words, The length value defined is the shortest distance between the first side surface 201 of the adapter piece 20 and the intersection of the adjacent first side wall 112 and the first end surface 111 when the electrode assembly 10 is in the first state, According to the design of, the minimum length value of the first non-adhesive part 32 is limited to Thereby avoiding the situation that the first non-adhesive part 32 is too short, resulting in the first insulating part 30 pulling on both the first side wall 112 of the main body part 11 and the adapter piece 20, and further reducing the risk of tearing at the connection between the adapter piece 20 and the first section 121 due to the expansion or movement of the main body part 11. In the first state, the first section 121 and the second section 122 of the tab bundle 12 extend along the first direction X of the main body part 11.

[0046] Among them, the first state of the electrode assembly 10 can be the flat state of the electrode assembly 10 before the core assembly step during the manufacturing process of the secondary battery 1, or after the secondary battery 1 is manufactured and assembled, when the electrode assembly 10 together with the adapter piece 20 is disassembled from the housing of the secondary battery 1, and the electrode assembly 10 is flattened to a flat state where the plane of the first side wall 112 of the main body part 11 is parallel to the plane of the side of the adapter piece 20 facing away from the first section 121.

[0047] In some embodiments, referring to Figures 1 - 8 , the secondary battery 1 includes two electrode assemblies 10. Referring to Figures 1 - 4 , Figure 6 and Figure 8 , the two electrode assemblies 10 include a first electrode assembly 101 and a second electrode assembly 102, and the first sections 121 of the tab bundles 12 of the two electrode assemblies 10 are respectively connected to the adapter piece 20. Referring to Figures 2 - 5 and Figures 9 - 10, each first insulating member 30 includes two first adhesive portions 31, two first non - adhesive portions 32 and a second adhesive portion 33. In the flattened state of the first insulating member 30, along the length direction of the first insulating member 30, the second adhesive portion 33 is disposed between the two first adhesive portions 31, and a first non - adhesive portion 32 is disposed between the second adhesive portion 33 and the adjacent first adhesive portion 31. Refer to Figures 1 - 5 and Figure 8 , one first adhesive portion 31 in the same first insulating member 30 is adhesively connected to the first side wall 112 of the first electrode assembly 101, and the other first adhesive portion 31 is adhesively connected to the first side wall 112 of the second electrode assembly 102. The second adhesive portion 33 is adhesively connected to the surface of the connecting piece 20 facing away from the first section 121 of the tab bundle 12. Among the two tab bundles 12 with the same polarity, at least part of the surfaces of the two second sections 122 facing the first insulating member 30 are respectively covered by a first non - adhesive portion 32. Thus, through one first insulating member 30, an insulating coating between the two electrode assemblies 10 and the connecting piece 20 is formed simultaneously. The arrangement of the two first non - adhesive portions 32 can form isolation and separation between the second adhesive portion 33 and the adjacent first adhesive portion 31, thereby reducing the pulling force of the second adhesive portion 33 on the connection between the connecting piece 20 and the first section 121 of the tab bundle 12 in the two electrode assemblies 10, and further reducing or even eliminating the risk of tearing of the first insulating member 30 at the connection between the connecting piece 20 and the first section 121. While increasing the use capacity of the secondary battery 1, the use safety and service life of the secondary battery 1 are improved. It should be noted that the two tab bundles 12 with the same polarity refer to the two positive tab bundles or the two negative tab bundles in the two electrode assemblies 102.

[0048] Among them, refer to Figures 1 - 3 , the first electrode assembly 101 and the second electrode assembly 102 are stacked along the second direction Y of the main body portion 11, so that the first side wall 112 of the first electrode assembly 101 and the first side wall 112 of the second electrode assembly 102 are respectively orthogonal to the surface of the connecting piece 20 facing away from the first section 121 of the tab bundle 12, that is, the combined - core state of the first electrode assembly 101 and the second electrode assembly 102 is formed, which is also the second state of the electrode assembly 10.

[0049] Refer to Figure 9 and Figure 13 , in the flattened state of the first insulating member 30, along the length direction of the first insulating member 30, among the two first non - adhesive portions 32, the length of one first non - adhesive portion 32 is L 111 mm, and the length of the other first non - adhesive portion 32 is L 112 mm. Among the two first adhesive portions 31, the length of one first adhesive portion 31 is L 12 mm, and the length of the other first adhesive portion 31 is L 14mm, the length of the second adhesive part 33 is L 13 mm. Among them, the length L of the second adhesive part 33 13 is related to the length of the adapter piece 20 in the first direction X, and can be specifically selected according to the length of the adapter piece 20. In the embodiments of the present application, the length L of the second adhesive part 33 13 is not specifically limited.

[0050] In some embodiments, L 12 = L 14 , that is, the lengths of the two first adhesive parts 31 are the same.

[0051] In some embodiments, L 12 = L 14 < L 13 , that is, the lengths of the two first adhesive parts 31 are respectively less than the length of the second adhesive part 33.

[0052] In some embodiments, L 111 = L 112 , that is, the lengths of the two first non - adhesive parts 32 are the same, both being the length L of the first non - adhesive part 32 as described above 11 .

[0053] In some embodiments, 10mm ≤ L 12 = L 14 ≤ 30mm. Specifically, the values of L 12 and L 14 can be any value among 10mm, 12mm, 15mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm or any value within the range composed of any two of these values. When the values of L 12 and L 14 are within the above range, the connection strength between the first adhesive part 31 and the first side wall 112 of the main body part 11 of the electrode assembly 10 can be ensured, the first insulating part 30 can be prevented from falling off from the first side wall 112, and the cost increase caused by the excessive adhesive range between the first adhesive part 31 and the first side wall 112 can be avoided.

[0054] In some embodiments, 6mm ≤ L 111 = L 112 ≤ 17.5mm. Specifically, L 111 and L 112The values can be any one of 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, 10.5mm, 11mm, 11.5mm, 12mm, 12.5mm, 13mm, 13.5mm, 14mm, 14.5mm, 15mm, 15.5mm, 16mm, 16.5mm, 17mm, 17.5mm or any value within the range formed by any two of these values. Among them, L 111 = L 112 = L 11 , that is, L 111 and L 112 both correspond to the length L 11 of the aforementioned first non-adhesive portion 32. Combining the defined above, it can be obtained that the value of is 5.2mm, and the value of F + G + S is 12.5mm. When the values of L 111 and L 112 are within the above range, it is possible to avoid the situation where the first insulating member 30 pulls on both the first side wall 112 of the main body portion 11 and the adapter piece 20 due to the too short length of the first non-adhesive portion 32, thereby reducing the risk of tearing at the connection between the adapter piece 20 and the first section 121 caused by the expansion or movement of the main body portion 11. It can also reduce the manufacturing cost of the first insulating member 30 and ensure that the length of the first non-adhesive portion 32 covers the surface of the second section 122 facing the first insulating member 30, improving the service life of the secondary battery 1.

[0055] In some embodiments, 20mm ≤ L 11 + L 12 ≤ 40mm, and the value of L 11 + L 12 can be any one of 20mm, 23mm, 30mm, 35mm, 40mm or any value within the range formed by any two of these values. Among them, the sum of L 11 and L 12 is a fixed value. When the sum of L 11 and L 12 is within the above range, it is applicable to the electrode assembly 10 with a thickness of 10mm to 30mm. For example, when L 11 + L 12 = 20mm, it is applicable to the electrode assembly 10 with a thickness of 10mm to 20mm. When L 11 + L 12 = 30mm, it is applicable to the electrode assembly 10 with a thickness of 15mm to 25mm. When L 11 + L 12 = 23mm, it is applicable to the electrode assembly 10 with a thickness of 16mm to 26mm. L11 +L 12 When = 40 mm, it is applicable to the electrode assembly 10 with a thickness of 20 mm to 30 mm. Specifically, the thickness of the electrode assembly 10 refers to the thickness of the main body 11 of the electrode assembly 10. More specifically, the thickness of the electrode assembly 10 refers to the distance between the first side wall 112 and the second side wall 113 of the main body 11 of the electrode assembly 10 in the second direction Y. When L 11 +L 12 is within the above range, L 11 and L 12 can be adjusted within a fixed value, so as to reduce the risk of tearing at the connection between the adapter piece 20 and the first section 121 caused by the expansion or movement of the main body 11, while ensuring the adhesive strength between the first adhesive part 31 and the first side wall 112, avoiding the detachment of the first insulating part 30, and reducing the defective rate of damaged tabs.

[0056] In some embodiments, referring to Figure 12 , the number of the electrode assemblies 10 in the secondary battery 1 is one. Figure 12 As shown in Figure 13 , the first state formed after the electrode assembly 10 is flattened. Referring to Figure 13 , the first insulating part 30 includes a first adhesive part 31, a first non - adhesive part 32, and a second adhesive part 33 arranged in sequence along the length direction of the first insulating part 30. The first adhesive part 31 is adhesively connected to the first side wall 112 of the main body 11, the second adhesive part 33 is adhesively connected to one side of the adapter piece 20 facing away from the first section 121 of the tab bundle 12, and at least part of the side of the second section 122 of the tab bundle 12 facing the first insulating part 30 is covered by the first non - adhesive part 32. Along the length direction of the first insulating part 30, the length of the first adhesive part 31 is L 12 mm, the length of the first non - adhesive part 32 is L 11 mm, and the length of the second adhesive part 33 is L 13 mm.

[0057] In some embodiments, referring to Figures 1 - 8 , Figures 11 - 12 and Figure 14 , the secondary battery 1 further includes a second insulating part 40. The second insulating part 40 includes a third adhesive part 41, a second non - adhesive part 42, and a fourth adhesive part 43. Along the length direction of the second insulating part 40, the second non - adhesive part 42 is arranged between the third adhesive part 41 and the fourth adhesive part 43. Referring to Figures 4 - 8, the first section 121 of the tab bundle 12 is welded to the adapter plate 20 to form a welding mark 123 on the first section 121. Specifically, the adapter plate 20 and the first section 121 of the tab bundle 12 are welded together by laser welding, ultrasonic welding, resistance welding or other methods. During the welding process, the first section 121 is penetrated and melted along the thickness direction, and a part of the adapter plate 20 is also melted, and the first section 121 and the adapter plate 20 are welded together. At the same time, a welding mark 123 is formed on the surface of the first section 121 facing away from the adapter plate 20.

[0058] Refer to Figures 4 - 8 , the third adhesive part 41 is adhesively connected to the second side wall 113 of the main body part 11, and at least a part of the side of the second section 122 of the tab bundle 12 facing the second insulating part 40 is covered by the second non - adhesive part 42. Specifically, in the embodiment shown in Figures 4 - 8 , the entire side of the second section 122 facing the second insulating part 40 is covered by the second non - adhesive part 42. In other words, the orthographic projection of the second section 122 on the plane where the second side wall 113 is located falls within the orthographic projection of the second non - adhesive part 42 on the plane where the second side wall 113 is located.

[0059] Refer to Figures 4 - 8 , the fourth adhesive part 43 is adhesively connected to the side of the first section 121 facing away from the adapter plate 20, and the fourth adhesive part 43 covers at least the welding mark 123, that is, the welding mark 123 formed on the first section 121 is at least covered by the fourth adhesive part 43. Specifically, in the embodiment shown in Figures 4 - 8 , the entire side of the first section 121 facing away from the adapter plate 20 is covered by the fourth adhesive part 43.

[0060] During the manufacturing process of the secondary battery, after the tab bundle is welded to the adapter plate, it is necessary to attach adhesive tape to the side of the tab bundle facing away from the adapter plate to play an insulating role and prevent the tab bundle from contacting the main body part and causing a short - circuit. However, during the cyclic use of the secondary battery, the main body part will expand and move. During the expansion and movement of the main body part, the adhesive tape attached to the main body part will be pulled. The pulling force of the main body part on the adhesive tape is transmitted to the tab bundle through the adhesive tape, generating a pulling force on the tab bundle. Since the tab bundle is welded to the adapter plate and a welding mark is formed, the connection strength at the edge position of the welding mark of the tab bundle is relatively weak, and the pulling force received by the tab bundle is likely to cause tearing at the edge position of the welding mark. The damage of the tab bundle leads to an increase in the internal resistance of the secondary battery and an increased risk of short - circuit between the inserted tab bundle and the main body part, affecting the capacity and use safety of the secondary battery.

[0061] The secondary battery 1 provided by the embodiment of the present application, by providing a second insulating member 40, the second insulating member 40 includes a third adhesive portion 41, a second non-adhesive portion 42 and a fourth adhesive portion 43. The second non-adhesive portion 42 is disposed between the third adhesive portion 41 and the fourth adhesive portion 43, and adhesively connects the third adhesive portion 41 to the second side wall 113 of the main body portion 11, and adhesively connects the second adhesive portion 33 to the surface of the first section 121 facing away from the adapter tab 20, and the second adhesive portion 33 covers at least the welding mark 123 on the first section 121. At least a part of the surface of the second section 122 of the tab bundle 12 facing the second insulating member 40 is covered by the second non-adhesive portion 42. The second adhesive portion 33 is adhesively connected to the first section 121, which can form an insulating coating for the first section 121 and can protect the welding mark 123. The adhesive connection between the third adhesive portion 41 and the second side wall 113 of the main body portion 11 can ensure the connection stability between the second insulating member 40 and the main body portion 11. The setting of the second non-adhesive portion 42 between the third adhesive portion 41 and the fourth adhesive portion 43 can form isolation and separation of the third adhesive portion 41 and the fourth adhesive portion 43, that is, the third adhesive portion 41 and the fourth adhesive portion 43 are not directly connected. When the main body portion 11 of the electrode assembly 10 expands and / or shakes, driving the third adhesive portion 41 to move and pulling on the second insulating member 40, the second non-adhesive portion 42 can reduce the pulling force transmitted to the fourth adhesive portion 43. The reason is that the second non-adhesive portion 42 is not coated with an adhesive coating, thereby cutting off the connection between the adhesive coating forming the third adhesive portion 41 and the adhesive coating forming the fourth adhesive portion 43, thereby reducing the pulling force of the second insulating member 40 on the first section 121 of the tab bundle 12, and further reducing or even eliminating the tearing risk of the edge position of the welding mark 123 on the first section 121. It can avoid the increase in the internal resistance of the secondary battery caused by the tearing damage of the first section 121 of the tab bundle 12, and can also avoid the short circuit caused by the insertion of the torn tab bundle 12 into the main body portion 11. Moreover, the adhesive covering of the welding mark 123 can effectively prevent the debris at the welding mark 123 from falling off and causing a micro short circuit, improving the use safety and service life of the secondary battery 1.

[0062] In some embodiments, referring to Figure 14 , in the flattened state of the second insulating member 40, along the length direction of the second insulating member 40, the length of the second non-adhesive portion 42 is L 21 mm, referring to Figure 4, in the first state of the electrode assembly 10, the distance between the plane where the first surface 1211 of the first section 121 of the tab bundle 12 is located and the plane where the second side wall 113 of the main body 11 is located in the second direction Y is B mm, 16 mm ≤ B ≤ 20 mm. Specifically, the value of B can be any value among 16 mm, 17 mm, 18 mm, 19 mm, 20 mm or any value within the range value composed of any two of these values. Refer to Figure 4 and Figure 5 , in the first state of the electrode assembly 10, the solder mark 123 has a third end face 1231 and a fourth end face 1232 arranged oppositely along the first direction X. The third end face 1231 is adjacent to the first end face 111 of the main body 11 in the first direction X. The distance between the plane where the third end face 1231 is located and the plane where the first end face 111 of the main body 11 is located in the first direction X is C mm, 7 mm ≤ C ≤ 11 mm. Specifically, the value of C can be any value among 7 mm, 8 mm, 9 mm, 10 mm, 11 mm or any value within the range value composed of any two of these values. Satisfy: S is the margin, 2 mm ≤ S ≤ 10 mm.

[0063] Wherein, refer to Figure 4 , The length value defined by is the straight-line distance between the third end face 1231 of the solder mark 123 and the intersection of the second side wall 113 adjacent to the third end face 1231 and the first end face 111 obtained according to the Pythagorean theorem. In other words, The length value defined by 21 is the shortest distance between the third end face 1231 of the solder mark 123 and the intersection of the second side wall 113 adjacent to the third end face 1231 and the first end face 111. When the length L of the second non-glued part 42 is 21 After the second insulating part 40 completes the adhesive connection with the second side wall 113 and the first section 121, the second non-glued part 42 is in a straightened and flat state. When L is greater than 21When the range is within the range defined above, it can be ensured that the surface of the second section 122 of the tab bundle 12 facing the second insulating member 40 can be covered by the second non-adhesive portion 42, and the second insulating member 40 will not pull on both the second side wall 113 of the main body portion 11 and the first section 121 of the tab bundle 12 due to the too short length of the second non-adhesive portion 42, resulting in a risk of tearing at the edge of the solder mark 123 on the first section 121 of the tab bundle 12. Thus, it is possible to avoid the third adhesive portion 41 and the fourth adhesive portion 43 after pasting from pulling on the second non-adhesive portion 42, reduce the manufacturing cost of the first insulating member 30, ensure that the length of the second non-adhesive portion 42 covers the surface of the second section 122 facing the second insulating member 40, reduce the risk of tearing of the first section 121 of the tab bundle 12 located at the edge of the solder mark 123 by the second insulating member 40 when the main body portion 11 expands or moves, and improve the service life and use safety of the secondary battery 1.

[0064] S is the allowance, 2mm ≤ S ≤ 10mm. The allowance S is the deviation allowance of the pasting device for attaching the second insulating member 40 to the second side wall 113 and the first section 121. Specifically, the value of S can be any value among 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or any value in the range value composed of any two of these values. Since the value of is less than B + C, By further expanding the length of the first non-adhesive portion 32 according to the range limitation, the second non-adhesive portion 42 can have sufficient length and be applicable to electrode assemblies 10 of different models and different thicknesses, so as to reduce the risk of tearing of the first section 121 of the tab bundle 12 located at the edge of the solder mark 123 by the second insulating member 40 when the main body portion 11 expands or moves, thereby reducing the defective rate of damaged tabs and improving the service life and use safety of the secondary battery 1.

[0065] In some embodiments, referring to Figures 1 - 8 , the secondary battery 1 includes two electrode assemblies 10. Referring to Figures 1 - 4 , Figure 6 and Figure 8 , the two electrode assemblies 10 include a first electrode assembly 101 and a second electrode assembly 102, and the first section 121 of each tab bundle 12 is respectively connected to the adapter piece 20. Referring to Figure 4 , Figures 6 - 8 and Figure 11 , each second insulating member 40 includes two third adhesive portions 41, two second non-adhesive portions 42 and one fourth adhesive portion 43. Along the length direction of the second insulating member 40, the fourth adhesive portion 43 is disposed between the two third adhesive portions 41, and a second non-adhesive portion 42 is disposed between the fourth adhesive portion 43 and the adjacent third adhesive portion 41. Referring to Figure 4 and Figures 6 - 8, one of the third adhesive parts 41 in the same second insulating part 40 is adhesively connected to the second side wall 113 of the first electrode assembly 101, and the other third adhesive part 41 is adhesively connected to the second side wall 113 of the second electrode assembly 102. The fourth adhesive part 43 is adhesively connected to the surface of the first section 121 of the two electrode assemblies 10 facing away from the connecting piece 20. In other words, in the two ear bundles 12 of the same polarity, the surface of the first section 121 facing away from the connecting piece 20 is respectively covered by the fourth adhesive part 43. In the two second non-adhesive parts 42, at least part of the surface of the second section 122 facing the second insulating part 40 is respectively covered by one second non-adhesive part 42. Thus, through one second insulating part 40, the insulating coating of the ear bundles 12 of the two electrode assemblies 10 is simultaneously formed. The arrangement of the two second non-adhesive parts 42 can form an isolation and separation between the fourth adhesive part 43 and the adjacent third adhesive part 41, thereby reducing the pulling force of the fourth adhesive part 43 on the edge position of the welding mark 123 on the first section 121 of the ear bundles 12 in the two electrode assemblies 10, and further reducing or even eliminating the tearing risk of the second insulating part 40 to the edge position of the welding mark 123 on the first section 121. While increasing the use capacity of the secondary battery 1, the use safety and service life of the secondary battery 1 are improved.

[0066] Refer to Figure 11 and Figure 14 , in the flattened state of the second insulating part 40, along the length direction of the second insulating part 40, among the two second non-adhesive parts 42, the length of one second non-adhesive part 42 is L 211 mm, and the length of the other second non-adhesive part 42 is L 212 mm. Among the two third adhesive parts 41, the length of one third adhesive part 41 is L 22 mm, and the length of the other third adhesive part 41 is L 24 mm. The length of the fourth adhesive part 43 is L 23 mm.

[0067] In some embodiments, L 22 =L 24 , that is, the lengths of the two third adhesive parts 41 are the same.

[0068] In some embodiments, L 22 =L 24 <L 23 , that is, the lengths of the two third adhesive parts 41 are respectively less than the length L of the fourth adhesive part 43 23 . Among them, the length L 23 of the fourth adhesive part 43 is related to the lengths of the two welding marks 123 on the two first sections 121 of the two electrode assemblies 10 in the first direction X. It is only necessary to ensure that the length of the fourth adhesive part 43 can cover the two welding marks 123. In the embodiments of the present application, the length L of the fourth adhesive 43 is not limited23 Make specific limitations.

[0069] In some embodiments, L 211 = L 212 , that is, the lengths of the two second non-adhesive portions 42 are the same, both being the length L of the second non-adhesive portion 42 as described above 21 .

[0070] In some embodiments, 10 mm ≤ L 22 = L 24 ≤ 25 mm. Specifically, the values of L 22 and L 24 can be any value among 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 25 mm or any value within the range formed by any two of these values. When the values of L 22 and L 24 are within the above range, the connection strength between the third adhesive portion 41 and the second side wall 113 of the main body portion 11 of the electrode assembly 10 can be ensured, preventing the second insulating member 40 from detaching from the second side wall 113, and also avoiding an excessive adhesive range between the third adhesive portion 41 and the second side wall 113, which may lead to increased costs.

[0071] In some embodiments, 15 mm ≤ L 211 = L 212 ≤ 35 mm. Specifically, the values of L 211 and L 212 can be any value among 15 mm, 20 mm, 22 mm, 22.5 mm, 23 mm, 23.5 mm, 24 mm, 24.5 mm, 25 mm, 25.5 mm, 26 mm, 26.5 mm, 27 mm, 27.5 mm, 28 mm, 28.5 mm, 29 mm, 29.5 mm, 30 mm, 30.5 mm, 31 mm, 31.5 mm, 32 mm, 32.5 mm, 33 mm, 33.5 mm, 34 mm, 34.5 mm, 35 mm or any value within the range formed by any two of these values. Among them, L 211 = L 212 = L 21 , that is, L 211 and L 212 both correspond to the length L of the aforementioned second non-adhesive portion 42 21 . Combining the limitations described above it can be obtained that the value of is 22 mm, and the value of B + C + S is 35 mm. When L 211 and L 212When the value is within the above range, it is possible to avoid the situation where the second non-adhesive portion 42 is too short in length, resulting in the second insulating member 40 pulling on both the second side wall 113 of the main body portion 11 and the first section 121 of the tab bundle 12. Furthermore, it reduces the risk of tearing of the edge area of the solder joint 123 on the first section 121 due to the expansion or movement of the main body portion 11. It can also reduce the manufacturing cost of the second insulating member 40 and ensure that the length of the second non-adhesive portion 42 covers the side of the second section 122 facing the second insulating member 40, thereby enhancing the service life of the secondary battery 1.

[0072] In some embodiments, 30mm ≤ L 21 +L 22 ≤ 50mm. Specifically, L 21 +L 22 The value can be any value among 30mm, 40mm, 45mm, 46.5mm, 50mm or any value within the range formed by any two of these values. Among them, the sum of L 21 and L 22 is a fixed value. When the sum of L 21 and L 22 is within the above range, it is applicable to electrode assemblies 10 with a thickness of 10mm to 30mm. For example, when L 21 +L 22 = 30mm, it is applicable to electrode assemblies 10 with a thickness of 10mm to 20mm. When L 21 +L 22 = 40mm, it is applicable to electrode assemblies 10 with a thickness of 15mm to 25mm. When L 21 +L 22 = 46.5mm, it is applicable to electrode assemblies 10 with a thickness of 16mm to 26mm. When L 21 +L 22 = 50mm, it is applicable to electrode assemblies 10 with a thickness of 20mm to 30mm. When the value of L 21 +L 22 is within the above range, the values of L 21 and L 22 can be adjusted within a fixed value, thereby reducing the risk of tearing of the edge area of the solder joint 123 on the first section 121 due to the expansion or movement of the main body portion 11, while ensuring the adhesive strength between the third adhesive portion 41 and the second side wall 113, preventing the second insulating member 40 from falling off, and reducing the defective rate of damaged tabs.

[0073] In some embodiments, referring to Figure 8 , the secondary battery 1 further includes a third insulating member 60. The third insulating member 60 is adhesively connected to the first section 121, and the third insulating member 60 covers at least the solder joint 123. Specifically, as shown in Figure 8In the illustrated embodiment, the third insulating member 60 is adhesively connected to the side of the first section 121 facing away from the adapter tab 20, and the fourth adhesive portion 43 of the second insulating member 40 is adhesively connected to the side of the third insulating member 60 facing away from the first section 121. Referring to Figure 6 and Figure 7 , in the first state, the first electrode assembly 101 and the second electrode assembly 102 are spaced apart along the first direction X. The third end face 1231 of the welding mark 123 on the first section 121 of the tab bundle 12 in the first electrode assembly 101 and the third end face 1231 of the welding mark 123 on the first section 121 of the tab bundle 12 in the second electrode assembly 102 have a spacing of L3 mm in the first direction X. Referring to Figure 8 , in the first state, the length of the third insulating member 60 in the first direction X is L4 mm; then it satisfies: L3 < L4, so that the welding marks 123 on the tab bundle 12 of the first electrode assembly 101 and the welding marks 123 on the tab bundle 12 of the second electrode assembly 102 can both be covered by the third insulating member 60, forming an insulating protection for the welding marks 123. Combining with the coverage of the welding marks 123 on the tab bundle 12 of the first electrode assembly 101 and the welding marks 123 on the tab bundle 12 of the second electrode assembly 102 by the fourth adhesive portion 43 in the second insulating member 40, it can effectively avoid the situation that the welding marks 123 are exposed due to the sticking error or the sticking deviation margin S of the sticking device, and ensure the insulating protection of the welding marks 123.

[0074] In some embodiments, referring to Figure 6 and Figure 7 , in the first state, one end of the second non - adhesive portion 42 of the second insulating member 40 adjacent to the first end face 111 of the main body portion 11 in the first direction X overlaps with the second side wall 113 of the main body portion 11. The length of the second non - adhesive portion 42 overlapping with the second side wall 113 in the first direction X is H mm, where 0 < H ≤ 3 mm. Specifically, the value of H can be any value among 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm or any value within the range composed of any two of these values. When the value of H is within the above range, one end of the second non - adhesive portion 42 facing away from the fourth adhesive portion 43 extends to the second side wall 113 of the main body portion 11, while ensuring the connection stability between the third adhesive portion 41 in the second insulating member 40 and the second side wall 113, further reducing the pulling force on the edge area of the welding mark 123 on the first section 121 of the tab bundle 12 when the main body portion 11 expands and / or moves, and improving the use safety and service life of the secondary battery 1.

[0075] In some embodiments, referring to Figure 10, the connection between the first adhesive part 31 and the first non - adhesive part 32 can be set in shapes such as an arc or a broken line. The connection between the first non - adhesive part 32 and the second adhesive part 33 can be set in shapes such as an arc or a broken line. Specifically, it can be designed according to actual usage requirements, as long as the adhesive connection between the first adhesive part 31 and the first side wall 112 of the main body part 11, the adhesive connection between the second adhesive part 33 and the adapter piece 20, and the side of the second section 122 of the tab bundle 12 facing the first insulating part 30 are covered by the first non - adhesive part 32 are ensured.

[0076] In some embodiments, the connection between the third adhesive part 41 and the second non - adhesive part 42 can be set in shapes such as an arc or a broken line. The connection between the second non - adhesive part 42 and the fourth adhesive part 43 can be set in shapes such as an arc or a broken line. Specifically, it can be designed according to actual usage requirements, as long as the adhesive connection between the third adhesive part 31 and the second side wall 113 of the main body part 11, the adhesive connection between the fourth adhesive part 43 and the first section 121 and covering the welding mark 123, and the side of the second section 122 of the tab bundle 12 facing the second insulating part 40 are covered by the second non - adhesive part 42 are ensured.

[0077] The following further describes the present application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.

[0078] Embodiment 1

[0079] Prepare a secondary battery:

[0080] Stack the positive electrode sheet, the separator, and the negative electrode sheet in sequence. The separator uses a PP (polypropylene) / PE (polyethylene) / PP composite film. The part of the positive electrode sheet where the positive electrode active material layer is not coated is cut to form a positive electrode tab sheet, and the part of the negative electrode sheet where the negative electrode active material layer is not coated is cut to form a negative electrode tab sheet. Then, the positive electrode sheet, the separator, and the negative electrode sheet are wound into a main body part 11. After winding, multiple positive electrode tab sheets are stacked to form a positive electrode tab bundle 12a, and multiple negative electrode tab sheets are stacked to form a negative electrode tab bundle 12b. Refer to Figures 4 - 8 , weld and connect the first section 121 of the positive electrode tab bundle 12a to an adapter piece 20, and weld and connect the first section 121 of the negative electrode tab bundle 12b to another adapter piece 20;

[0081] Refer to Figures 4 - 5 And Figure 8, one first adhesive part 31 of the first insulating part 30 is adhesively connected to the first side wall 112 of the main body part 11 of the first electrode assembly 101, and the other first adhesive part 31 is adhesively connected to the first side wall 112 of the main body part 11 of the second electrode assembly 102. The second adhesive part 33 is adhesively connected to the first surface of the adapter plate 20 facing away from the first section 121, and the second section 122 of the tab bundle 12 of the first electrode assembly 101 is covered by a first non - adhesive part 32 on the side facing the first insulating part 30, and the second section 122 of the tab bundle 12 of the second electrode assembly 102 is covered by another first non - adhesive part 32 on the side facing the first insulating part 30.

[0082] Refer to Figures 4 - 8 , one third adhesive part 41 of the second insulating part 40 is adhesively connected to the second side wall 113 of the main body part 11 of the first electrode assembly 101, and the other third adhesive part 41 is adhesively connected to the second side wall 113 of the main body part 11 of the second electrode assembly 102. The fourth adhesive part 43 is adhesively connected to the surface of the first section 121 of the tab bundle 12 of the first electrode assembly 101 facing away from the adapter plate 20 and the surface of the first section 121 of the tab bundle 12 of the second electrode assembly 102 facing away from the adapter plate 20. The fourth adhesive part 43 covers the welding marks 123 on the two first sections 121, and the second section 122 of the tab bundle 12 of the first electrode assembly 101 is covered by a second non - adhesive part 42 on the side facing the second insulating part 40, and the second section 122 of the tab bundle 12 of the second electrode assembly 102 is covered by another second non - adhesive part 32 on the side facing the second insulating part 40.

[0083] Refer to Figures 1 - 3 , after the main body part 11 of the first electrode assembly 101 and the main body part 11 of the second electrode assembly 102 are turned over and combined, they are placed into the accommodation cavity 701 of the housing 70. The top cover plate 51 is covered on the opening of the housing 70. The terminal 50 is welded to the adapter plate 20, and electrolyte is injected into the accommodation cavity 701 of the housing 70 through the liquid injection hole on the top cover plate 51 to complete the assembly of the secondary battery 1.

[0084] Among them, the length L of the first non - adhesive part 32 in the first insulating part 30 11 and the length L of the first adhesive part 31 12 As shown in Table 1, the distance F between the plane where the surface of the adapter plate 20 facing away from the first section 121 of the tab bundle 12 is located and the plane where the first end face 111 of the main body part 11 is located is as shown in Table 1. The distance G between the plane where the end face of the adapter plate 20 adjacent to one end of the first side wall 112 is located and the plane where the first side wall 112 adjacent to the adapter plate 20 is located in the second direction Y is as shown in Table 1. The length L of the second non - adhesive part 42 in the second insulating part 40 21 and the length L of the third adhesive part 41 22As shown in Table 1, the distance B in the second direction Y between the plane where the first surface 1211 of the first section 121 of the tab bundle 12 is located and the plane where the second side wall 113 of the main body 11 is located is as shown in Table 1, and the distance C in the first direction X between the plane where the third end surface 1231 is located and the plane where the first end surface 111 of the main body 11 is located is as shown in Table 1.

[0085] Examples 2 to 27

[0086] Refer to the method for assembling the secondary battery 1 provided in Example 1. Except for the following differences, the rest are the same as in Example 1:

[0087] Adjust the length L of the first non-adhesive portion 32 11 and the length L of the first adhesive portion 31 12 , adjust the length L of the second non-adhesive portion 42 21 and the length L of the third adhesive portion 41 22 , and adjust the values of F, G, B, and C, as specifically shown in Table 1.

[0088] Comparative Example 1

[0089] Refer to the method for assembling the secondary battery 1 provided in Example 1. Except for the following differences, the rest are the same as in Example 1:

[0090] Use existing insulating adhesive tape to attach to the first side wall 112 of the main body 11, the second section 122 of the tab bundle 12, and the adapter piece 20, and use existing insulating adhesive tape to attach to the second side wall 113 of the main body 11, the second section 122 of the tab bundle 12, and the first section 121.

[0091] Length measurement method:

[0092] Take the secondary batteries 1 assembled in Examples 1 to 27 and Comparative Example 1, disassemble and assemble the electrode assembly 10 and the adapter piece 20 connected to the first section 121 of the tab bundle 12 from the housing 70 respectively, and use a micrometer to measure the length L of the first non-adhesive portion 32 11 and the length L of the first adhesive portion 31 12 , measure the length L of the second non-adhesive portion 42 21 and the length L of the third adhesive portion 41 22 , measure the values of F, G, B, and C, and the measurement results are shown in Table 1.

[0093] Test method for the defective rate of damaged tabs:

[0094] Conduct an appearance inspection on the electrode assembly 10 according to a certain tab cracking control value (such as a cracking length of less than 5 mm). Those exceeding the tab cracking control value are recorded as defective products, and the defective rate of damaged tabs = the number of defective products with damaged tabs / the total number of electrode assemblies 10.

[0095] Table 1

[0096]

[0097]

[0098] As can be seen from Table 1, referring to Embodiments 1 to 4, the length L of the first non-adhesive portion 32 in the first insulating member 30 11 and the length L of the first adhesive portion 31 12 remain unchanged and L 11 and L 12 sum is fixed. On the premise that the sum of the lengths of L 21 and L 22 remains at 46.5 mm, as the length of L 21 increases and the length of L 22 decreases, the defective rate of damaged tabs shows a downward trend, indicating that an increase in the length of the second non-adhesive portion 42 can ensure that the side of the second segment 122 of the tab bundle 12 facing the second insulating member 40 can be covered by the second non-adhesive portion 42, and it will not cause the second insulating member 40 to pull on both the second side wall 113 of the main body portion 11 and the first segment 121 of the tab bundle 12 due to the too short length of the second non-adhesive portion 42, reducing the risk of tearing at the edge of the welding mark 123 on the first segment 121 of the tab bundle 12, thereby reducing the defective rate of damaged tabs.

[0099] Similarly, referring to Embodiments 9 and 18, the length L of the first non-adhesive portion 32 in the first insulating member 30 11 and the length L of the first adhesive portion 31 12 remain unchanged and L 11 and L 12 sum is fixed. On the premise that the sum of the lengths of L 21 and L 22 remains at 30 mm, as the length of L 21 increases and the length of L 22 decreases, the defective rate of damaged tabs shows a downward trend.

[0100] Referring to Embodiments 20 to 21, the length L of the first non-adhesive portion 32 in the first insulating member 30 11 and the length L of the first adhesive portion 31 12 remain unchanged and L 11 and L 12 sum is fixed. On the premise that the sum of the lengths of L 21 and L 22 remains at 30 mm, as the length of L 21 increases and the length of L 22 decreases, the defective rate of damaged tabs shows a downward trend.

[0101] Referring to Embodiments 6 to 8, the length L of the second non-adhesive portion 42 in the second insulating member 40 21 and the length L of the third adhesive portion 41 22 remain unchanged and L 21 and L 22 Under the condition that the sum is fixed, when the sum of the lengths of L 21 and L 22 remains at 46.5 mm, as the length of L 11 increases and the length of L 12 decreases, the defective rate of the ear damage shows a downward trend, indicating that an increase in the length of the first non-adhesive portion 32 can ensure that the surface of the second section 122 of the ear bundle 12 facing the first insulating member 30 can be covered by the first non-adhesive portion 32, and it will not cause the first insulating member 30 to pull on both the first side wall 112 of the main body portion 11 and the adapter piece 20 due to the too short length of the first non-adhesive portion 32, reducing the tearing risk at the connection between the adapter piece 20 and the first section 121, thereby reducing the defective rate of the ear damage.

[0102] Referring to Embodiments 9 and 19, the length L of the second non-adhesive portion 42 in the second insulating member 40 21 and the length L of the third adhesive portion 41 22 remain unchanged and L 21 and L 22 Under the condition that the sum is fixed, when the sum of the lengths of L 21 and L 22 remains at 30 mm, the length of L 11 in Embodiment 19 is lower than the length of L 11 in Embodiment 9, and the length of L 12 in Embodiment 19 is higher than the length of L 12 in Embodiment 9, resulting in a defective rate of ear damage of 0.6% in the electrode assembly 10 of Embodiment 19, which is higher than the defective rate of ear damage of 0.5% in Embodiment 9. The reason is that the length of the first non-adhesive portion 32 in Embodiment 19 is 6 mm, which is lower than the length of the first non-adhesive portion 32 in Embodiment 9, which is 10 mm. As a result, the length of the first non-adhesive portion 32 of the first insulating member 30 used in Embodiment 19 is relatively short. When the main body portion 11 expands, the insulating layer 30 may pull on both the first side wall 112 and the adapter piece 20, thus increasing the tearing risk at the connection between the adapter piece 20 and the first section 121 in Embodiment 19, resulting in a higher defective rate of ear damage in the electrode assembly 10 of Embodiment 19 than in Embodiment 9.

[0103] Referring to Embodiments 14 to 15, in L 21 and L 22 remain unchanged and L 21 and L22 When the sum is fixed, at L 11 and L 12 remain unchanged and L 11 and L 12 When the sum is fixed, at L 21 and L 22 On the premise that the sum of the lengths remains at 46.5 mm, and when B, C, and G are the same, the F value in Example 14 is higher than that in Example 15, resulting in the defective rate of the tab in the electrode assembly 10 of Example 14 being 0.35%, higher than the defective rate of the tab of 0.25% in Example 15. Refer to Figure 3 , indicating that along the first direction X, the shorter the distance between the connecting piece 20 and the first end face 111 of the main body portion 11, at L 11 and L 12 remain unchanged and L 11 and L 12 When the sum is fixed, the pulling force received by the first non-adhesive portion 32 in Example 15 becomes smaller than that in Example 14, and the defective rate of the tab shows a downward trend.

[0104] Refer to Examples 16 to 17. At L 21 and L 22 remain unchanged and L 21 and L 22 When the sum is fixed, at L 11 and L 12 remain unchanged and L 11 and L 12 When the sum is fixed, at L 21 and L 22 On the premise that the sum of the lengths remains at 46.5 mm, and when B, C, and F are the same, the G value in Example 16 is higher than that in Example 17, resulting in the defective rate of the tab in the electrode assembly 10 of Example 16 being 0.30%, higher than the defective rate of the tab of 0.20% in Example 17. Refer to Figure 3 , indicating that along the second direction Y, the shorter the distance between the end face of the connecting piece 20 adjacent to one end of the first side wall 112 of the main body portion 11 and the first side wall 112 adjacent to the connecting piece 20, at L 11 and L 12 remain unchanged and L 11 and L 12 When the sum is fixed, the pulling force received by the first non-adhesive portion 32 in Example 17 becomes smaller than that in Example 16, and the defective rate of the tab shows a downward trend.

[0105] Refer to Examples 10 to 11. At L 21 and L 22 remain unchanged and L 21 and L22 When the sum is fixed, at L 11 and L 12 remain unchanged and L 11 and L 12 When the sum is fixed, at L 21 and L 22 On the premise that the sum of the lengths of is kept at 46.5 mm, and when C, F, and G are the same, the B value in Example 11 is higher than that in Example 10, resulting in the defective rate of the tab in the electrode assembly 10 of Example 11 being 0.40%, higher than the defective rate of the tab of 0.30% in Example 10. Refer to Figure 4 , indicating that along the second direction Y, the longer the distance between the first surface 1211 of the first section 121 and the second side wall 113 of the main body 11, at L 21 and L 22 remain unchanged and L 21 and L 22 When the sum is fixed, the pulling force received by the second non-adhesive part 42 in Example 11 becomes larger compared to Example 10, and the defective rate of the tab shows an increasing trend.

[0106] Refer to Examples 12 to 13. At L 21 and L 22 remain unchanged and L 21 and L 22 When the sum is fixed, at L 11 and L 12 remain unchanged and L 11 and L 12 When the sum is fixed, at L 21 and L 22 On the premise that the sum of the lengths of is kept at 46.5 mm, and when B, F, and G are the same, the C value in Example 13 is higher than that in Example 12, resulting in the defective rate of the tab in the electrode assembly 10 of Example 13 being 0.35%, higher than the defective rate of the tab of 0.30% in Example 12. Refer to Figure 4 and Figure 5 , indicating that along the second direction Y, the longer the distance between the third end face 1231 and the first end face 111 of the main body 11, at L 21 and L 22 remain unchanged and L 21 and L 22 When the sum is fixed, the pulling force received by the second non-adhesive part 42 in Example 13 becomes larger compared to Example 12, and the defective rate of the tab shows an increasing trend.

[0107] Refer to Examples 20 and 22. In the second non-adhesive part 42 of the second insulating member 40, the length L 21 and the length L of the third adhesive part 4122 remains unchanged and L 21 and L 22 When the sum is fixed, for L 21 and L 22 On the premise that the sum of the lengths of is maintained at 50 mm, the L in Example 22 11 has a length lower than that of the L in Example 20 11 The length of the L in Example 22 12 has a length higher than that of the L in Example 20 12 The length of, such that the defective rate of the tab in the electrode assembly 10 of Example 19 is 0.5%, higher than the defective rate of 0.4% of the tab in Example 20. The reason is that the length of the first non-glued part 32 in Example 22 is 10 mm, lower than the length of the first non-glued part 32 in Example 20, which is 20 mm. As a result, the length of the first non-glued part 32 of the first insulating part 30 used in Example 22 is shorter. When the main body part 11 expands, the insulating layer 30 may pull on both the first side wall 112 and the adapter piece 20, thus increasing the risk of tearing at the connection between the adapter piece 20 and the first section 121 in Example 22, resulting in a higher defective rate of the tab in the electrode assembly 10 in Example 22 than in Example 20.

[0108] Referring to Example 23, for the first insulating part 30 used in Example 23, when the sum of the lengths of L 11 and L 12 is 23 mm, for the second insulating part 40, the sum of the lengths of L 21 and L 22 is 46.5 mm, but the length of L 21 is 40 mm, and the length of L 22 is only 6.5 mm. Although the second non-glued part 42 in the second insulating part 40 can fully cover the second section 122 of the tab bundle 12, the length of the third adhesive part 41, L 22 is too short, resulting in poor adhesive strength between the second insulating part 40 and the second side wall 113 of the main body part 11. There is a high risk of the second insulating part 40 falling off during the expansion of the main body part 11, resulting in a defective rate of the tab in the electrode assembly 10 provided in Example 23 reaching 0.1%, which is significantly higher than that of the electrode assemblies 10 provided in Examples 1 to 8 where the sum of L 11 and L 12 is 23 mm and the sum of L 21 and L 22 is 46.5 mm.

[0109] Referring to Example 24, in the first insulating part 30 used in Example 24, the length of the first non-glued part 32, L 11 is only 4 mm. For L11 With L 12 When the sum with L is 23 mm, the too short first non - adhesive part 32 is difficult to cover the second section 122 of the tab bundle 12, resulting in the first insulating part 30 pulling on both the first side wall 112 of the main body part 11 and the adapter piece 20, increasing the risk of tearing at the connection between the adapter piece 20 and the first section 121. Furthermore, the defective rate of the tabs damaged in the electrode assembly 10 provided in Example 24 is as high as 3%.

[0110] Referring to Example 25, in the first insulating part 30 used in Example 25, the length L of the first non - adhesive part 32 11 is only 2 mm. When the sum of L 11 and L 12 is 23 mm, the too short first non - adhesive part 32 is difficult to cover the second section 122 of the tab bundle 12, resulting in the first insulating part 30 pulling on both the first side wall 112 of the main body part 11 and the adapter piece 20, increasing the risk of tearing at the connection between the adapter piece 20 and the first section 121. Furthermore, the defective rate of the tabs damaged in the electrode assembly 10 provided in Example 25 is as high as 5%.

[0111] Referring to Example 26, when L 21 and L 22 remain unchanged and the sum of L 21 and L 22 is fixed, and when L 11 and L 12 remain unchanged and the sum of L 11 and L 12 is fixed, on the premise that the sum of the lengths of L 21 and L 22 remains at 46.5 mm, the values of B, F, and G are all higher than the upper limit values in the defined range values, resulting in a relatively high pulling force on the first non - adhesive part 32 and the second non - adhesive part 42, and the defective rate of the tabs damaged in the electrode assembly 10 provided in Example 26 reaches 1.2%.

[0112] Referring to Example 27, when L 21 and L 22 remain unchanged and the sum of L 21 and L 22 is fixed, and when L 11 and L 12 remain unchanged and the sum of L 11 and L 12 is fixed, and when L 21 and L 22On the premise that the sum of the lengths remains at 46.5 mm, the values of B and F are higher than the upper limit value of the defined range value, and the value of C is lower than the lower limit value of the defined range value, resulting in a relatively high pulling force on the first non-adhesive part 32 and the second non-adhesive part 42, and the defective rate of the ear damage in the electrode assembly 10 provided in Example 27 reaches 1.6%.

[0113] On the contrary, in Comparative Example 1, in the electrode assembly 10 provided in Comparative Example 1, the existing insulating adhesive tape is used instead of the non-adhesive part, resulting in a large pulling force of the insulating adhesive tape on the ear bundle 12, the main body part 11 and the adapter piece 20. The tearing risk at the connection between the adapter piece 20 and the first section 121 and the tearing risk at the edge of the welding mark 123 on the first section 121 of the ear bundle 12 are both relatively high, resulting in a defective rate of up to 10% for the ear damage in the electrode assembly 10 provided in Comparative Example 4.

[0114] The technical solutions provided in the embodiments of the present application have been introduced in detail above. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A secondary battery, characterized in that: include: An electrode assembly (10), the electrode assembly (10) comprising a main body (11) and a tab bundle (12) connected to the main body (11), the main body (11) having a first direction (X) and a second direction (Y) intersecting each other, the main body (11) having a first end surface (111) intersecting the first direction (X) and a first side wall (112) intersecting the second direction (Y), the tab bundle (12) comprising a first section (121) and a second section (122) connected to each other, the second section (122) being connected to the main body (11) at the first end surface (111), and the first section (121) being located at an end of the second section (122) away from the main body (11); A transfer sheet (20), the transfer sheet (20) and the first section (121) are overlapped along the thickness direction of the first section (121), and the transfer sheet (20) and the first section (121) are connected; A first insulating member (30), comprising a first adhesive portion (31), a first non-adhesive portion (32) and a second adhesive portion (33), wherein the first non-adhesive portion (32) is arranged between the first adhesive portion (31) and the second adhesive portion (33), the first adhesive portion (31) is adhesively connected to the first side wall (112), the second adhesive portion (33) is adhesively connected to a side of the adapter sheet (20) facing away from the first section (121), and at least a portion of a side of the second section (122) facing the first insulating member (30) is covered by the first non-adhesive portion (32); The distance between the plane where the side of the adapter sheet (20) facing away from the first section (121) is located and the plane where the first end surface (111) is located in the first direction (X) is F mm, 3.5 mm≤F≤5.5 mm; Along the length direction of the adapter plate (20), the distance between the plane where the end surface of the adapter plate (20) adjacent to one end of the first side wall (112) is located and the plane where the adjacent first side wall (112) is located in the second direction (Y) is G mm, 1mm≤G≤2mm; When the first insulating member (30) is flattened, along the length direction of the first insulating member (30), the length of the first glue-free portion (32) is L 11 mm; meet: S is the margin, 2mm≤S≤10mm.

2. The secondary battery according to claim 1, wherein: The secondary battery comprises two electrode assemblies (10), the two electrode assemblies (10) comprising a first electrode assembly (101) and a second electrode assembly (102), and the first sections (121) of the tab bundles (12) of the two electrode assemblies (10) are respectively connected to the adapter sheet (20); Each of the first insulating members (30) comprises two first adhesive portions (31), two first adhesive-free portions (32) and one second adhesive portion (33); The second adhesive portion (33) is arranged between two of the first adhesive portions (31), and a first non-adhesive portion (32) is arranged between the second adhesive portion (33) and the adjacent first adhesive portion (31); One of the first adhesive portions (31) in the same first insulating member (30) is adhesively connected to the first side wall (112) of the first electrode assembly (101), and another of the first adhesive portions (31) is adhesively connected to the first side wall (112) of the second electrode assembly (102); The second adhesive portion (33) is adhesively connected to a side of the adapter sheet (20) facing away from the first section (121); In the two pole tab bundles (12) with the same polarity, at least parts of the two second sections (122) facing the first insulating member (30) are respectively covered by one of the first glue-free portions (32).

3. The secondary battery according to claim 2, characterized in that: When the first insulating member (30) is flattened, along the length direction of the first insulating member (30), the length of one of the first adhesive-free portions (32) is L 111 mm, and the length of the other first adhesive-free portion (32) is L 112 mm, and the length of the first adhesive portion (31) is L 12 mm, the length of the second adhesive portion (33) is L 13 mm, and the length of the other first adhesive portion (31) is L 14 mm; Then, at least one of the following conditions is met: 1)L 12 =L 14 ; 2)L 12 =L 14 <L 13 ; 3)L 111 =L 112 ; 4)10mm≤L 12 =L 14 ≤30mm; 5)6mm≤L 111 =L 112 ≤17.5mm; 6)20mm≤L 11 +L 12 ≤40mm。 4. The secondary battery according to any one of claims 1 to 3, characterized in that The secondary battery further includes a second insulating member (40); The second insulating member (40) comprises a third adhesive portion (41), a second adhesive-free portion (42) and a fourth adhesive portion (43) of the second insulating member, and along the length direction of the second insulating member (40), the second adhesive-free portion (42) is arranged between the third adhesive portion (41) and the fourth adhesive portion (43); The main body (11) further comprises a second side wall (113), the second side wall (113) and the first side wall (112) being arranged opposite to each other along the second direction (Y), the first section (121) being welded to the adapter sheet (20), and a welding mark (123) being formed on a surface of the first section (121) facing away from the adapter sheet (20); The third adhesive portion (41) is adhesively connected to the second side wall (113), and at least a portion of the second section (122) facing the second insulating member (40) is covered by the second non-adhesive portion (42); The fourth adhesive portion (43) is adhesively connected to a side of the first section (121) facing away from the adapter sheet (20), and at least covers the weld mark (123).

5. The secondary battery according to claim 4, characterized in that: When the second insulating member (40) is flattened, along the length direction of the second insulating member (40), the length of the second glue-free portion (42) is L 21 mm; When the electrode assembly (10) is flattened, it has a first state in which the plane where the first side wall (112) is located is parallel to the plane where the side of the adapter sheet (20) facing away from the first section (121) is located; Along the thickness direction of the first section (121), the first section (121) has a first surface (1211) and a second surface (1212) that are arranged opposite to each other, and the adapter sheet (20) is arranged to be connected to the second surface (1212); In the first state, the distance between the plane where the first surface (1211) is located and the plane where the second side wall (113) is located in the second direction (Y) is B mm, 16mm≤B≤20mm, the weld mark (123) has a third end face (1231) and a fourth end face (1232) arranged opposite to each other along the first direction (X), and the distance between the plane where the third end face (1231) is located and the plane where the first end face (111) is located in the first direction (X) is C mm, 7mm≤C≤11mm; satisfy: S is the margin, 2mm≤S≤10mm.

6. The secondary battery according to claim 5, characterized in that: The secondary battery comprises two electrode assemblies (10), the two electrode assemblies (10) comprising a first electrode assembly (101) and a second electrode assembly (102), and the first section (121) of each of the tab bundles (12) is respectively connected to the adapter sheet (20); Each of the second insulating members (40) comprises two of the third adhesive portions (41), two of the second adhesive-free portions (42) and one of the fourth adhesive portions (43); Along the length direction of the second insulating member (40), the fourth adhesive portion (43) is arranged between the two third adhesive portions (41), and a second adhesive-free portion (42) is arranged between the fourth adhesive portion (43) and the adjacent first adhesive portion (31); One of the third adhesive portions (41) in the same second insulating member (40) is adhesively connected to the second side wall (113) of the first electrode assembly (101), and another of the third adhesive portions (41) is adhesively connected to the second side wall (113) of the second electrode assembly (102); In the two tab bundles (12) with the same polarity, the first section (121) has a side facing away from the adapter sheet (20) respectively bonded to the fourth adhesive portion (43), and at least a portion of a side of the second section (122) of the two sections facing the second insulating member (40) is respectively covered by a second adhesive-free portion (42).

7. The secondary battery according to claim 6, characterized in that: When the second insulating member (40) is flattened, along the length direction of the second insulating member (40), the length of one of the second adhesive-free portions (42) is L 211 mm, and the length of the second adhesive-free portion (42) is L 212 mm, and the length of the third adhesive portion (41) is L 22 mm, the length of the fourth adhesive portion (43) is L 23 mm, and the length of the other third adhesive portion (41) is L 24 mm; Then, at least one of the following conditions is met: a)L 22 =L 24 ; b)L 22 =L 24 <L 23 ; c)L 211 =L 212 ; d)10mm≤L 22 =L 24 ≤25mm; e)15mm≤L 211 =L 212 ≤35mm; f)30mm≤L 21 +L 22 ≤50mm.

8. The secondary battery according to claim 5, characterized in that: The secondary battery comprises two electrode assemblies (10), the two electrode assemblies (10) comprising a first electrode assembly (101) and a second electrode assembly (102), and the first sections (121) of the tab bundles (12) of the two electrode assemblies (10) are respectively connected to the adapter sheet (20); The secondary battery further comprises a third insulating member (60), the third insulating member (60) being adhesively connected to the first section (121), and the third insulating member (60) at least covering the weld mark (123); In the first state, the first electrode assembly (101) and the second electrode assembly (102) are spaced apart along the first direction (X), a distance between a third end surface (1231) of the weld mark (123) on the first electrode assembly (101) and a third end surface (1231) of the weld mark (123) on the second electrode assembly (102) in the first direction (X) is L3 mm, and a length of the third insulating member (60) in the first direction (X) is L4 mm; Then it satisfies: L3<L4.

9. The secondary battery according to claim 5, characterized in that: In the first state, one end of the second non-glue portion (42) adjacent to the first end surface (111) in the first direction (X) overlaps with the second side wall (113); The length of the second non-glue portion (42) overlapping the second side wall (113) in the first direction (X) is H mm, 0<H≤3 mm.

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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