Battery cell assembly and battery comprising same

Abstract

The utility model relates to the technical field of batteries, and particularly provides a battery cell assembly and a battery comprising the same. The cell assembly comprises a positive plate, a negative plate, a diaphragm and a conductive sheet, the diaphragm is located between the positive plate and the negative plate, the diaphragm, the positive plate and the negative plate are wound to form a roll core, the roll core has an arc part, and the conductive sheet is attached to the arc part; the conductive sheet comprises a conductive base material and an insulating viscous coating, the insulating viscous coating is arranged in a partial area on at least one surface of the conductive base material, and the surface, provided with the insulating viscous coating, of the conductive base material is divided into a coating area and a gap area. In the application, the conductive sheet is attached to the easy-to-break part of the pole piece of the battery cell, and when the pole piece is broken, the conductive sheet can serve as a conductive bridge, so that the normal conduction of the broken part of the pole piece is ensured, and the problem that the battery capacity is suddenly reduced due to the breakage of the pole piece is avoided. The insulating adhesive coating is only coated on a part of area of the conductive base material, so that the bonding strength is ensured, the conductive base material can be in contact with the pole piece, and the conductive effect is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, and particularly discloses a battery cell assembly and a battery comprising the same. BACKGROUND

[0002] As a kind of secondary battery, lithium ion battery has been widely used in mobile phones, notebook computers and electric vehicles due to its high energy density and good charge-discharge cycle capability.

[0003] At present, as the market requires higher energy density of batteries, manufacturers are gradually increasing the compaction density of battery internal cell assemblies, which causes the arc part of the pole piece to bear a large shrinkage stress during the charge-discharge process of the battery. When the stress distribution on the pole piece is uneven, the pole piece is prone to breakage, which causes part of the materials inside the battery cell to fail due to inability to conduct electricity. SUMMARY

[0004] The present application aims to solve at least part of the technical problems mentioned above, and the purpose is achieved by the following technical solutions:

[0005] In a first aspect, the present application provides a battery cell assembly, which comprises a positive pole piece, a negative pole piece, a separator and a conductive sheet, the separator is located between the positive pole piece and the negative pole piece, and the three are wound to form a roll core, the roll core has an arc part, and the conductive sheet is attached to the arc part; the conductive sheet comprises a conductive base material and an insulating adhesive coating, part of the area on at least one side of the conductive base material is provided with the insulating adhesive coating, and the side of the conductive base material provided with the insulating adhesive coating is divided into a coating area and a gap area.

[0006] In some embodiments, the electrical conductivity of the conductive base material is σ, and σ≥1*10-2S / m is satisfied; and / or, the conductive base material is a metal foil, a composite foil composed of metal and polymer or a carbon-based material.

[0007] In some embodiments, the area of the coating area is S1, the area of the gap area is S2, and 20%≤S2 / (S1+S2)≤80% is satisfied.

[0008] In some embodiments, the coating area is a regular shape or an irregular shape, and / or the gap area is continuously distributed or spacedly distributed.

[0009] In some embodiments, the coating area is a regular shape and is spacedly distributed, the distance between adjacent coating areas is D, and 1mm≤D≤10mm is satisfied.

[0010] In some embodiments, the coating area is an irregular shape, and S2≥2mm 2 .

[0011] In some embodiments, the circular arc portion includes a first circular arc portion and a second circular arc portion located at two ends of the winding core in the first direction, and at least one of the first circular arc portion and the second circular arc portion is provided with the conductive sheet.

[0012] In some embodiments, the first circular arc portion and the second circular arc portion each have a plurality of circular arc layers along the first direction, and at least one circular arc layer of the first circular arc portion and / or the second circular arc portion is provided with the conductive sheet.

[0013] In some embodiments, the thickness of the conductive sheet is d, the thickness of the conductive substrate is d1, and the thickness of the insulating adhesive coating is d2, and 8 μm≤d≤30 μm, 5 μm≤d1≤25 μm, and 1 μm≤d2≤10 μm are satisfied.

[0014] In some embodiments, the width of the conductive sheet is W, and 5 mm≤W≤30 mm is satisfied.

[0015] In a second aspect, the application provides a battery comprising the battery core assembly of the first aspect.

[0016] The technical solutions provided by the application have at least the following technical effects:

[0017] In the application, the conductive sheet is attached to the fracture-prone part of the core tab, i.e., at least the outer layer of the winding core circular arc portion. When the tab breaks, the conductive sheet can act as a conductive bridge to ensure that the broken part of the tab can conduct electricity normally, thereby avoiding the problem of sudden capacity drop of the battery caused by tab breakage, thereby ensuring the cycle performance of the battery. In addition, the insulating adhesive coating is used instead of the conventional conductive adhesive layer for bonding, thereby avoiding the dissolution of metal particles in the conductive adhesive layer under the soaking of the electrolyte, which can cause internal short circuit of the battery. Furthermore, the insulating adhesive coating is only coated on part of the area of the conductive substrate, which ensures the bonding strength while enabling the conductive substrate to be in contact with the tab to achieve the effect of conduction. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to better combine the content shown in the drawings of the specification with the content described in the detailed description, the drawings of the specification are briefly introduced as follows. It can be understood that the drawings of the specification mentioned below only schematically show the related technical solutions and some embodiments of the technical solutions of the application, and under the premise of not paying creative labor, a person skilled in the art can also make drawings showing other embodiments.

[0019] Specifically, the annotations of the drawings of the specification are as follows:

[0020] Figure 1 The cross-sectional view of the first conductive sheet described in some embodiments of the application is shown.

[0021] Figure 2A top view of a first conductive sheet as described in some embodiments of the present application;

[0022] Figure 3 A top view of a second conductive sheet as described in some embodiments of the present application;

[0023] Figure 4 A top view of a third conductive sheet as described in some embodiments of the present application;

[0024] Figure 5 A top view of a fourth conductive sheet as described in some embodiments of the present application;

[0025] Figure 6 A top view of a fifth conductive sheet as described in some embodiments of the present application;

[0026] Figure 7 A top view of a first battery cell assembly as described in some embodiments of the present application;

[0027] Figure 8 A top view of a second battery cell assembly as described in some embodiments of the present application;

[0028] Figure 9 A top view of a third battery cell assembly as described in some embodiments of the present application;

[0029] Figure 10 A top view of a fourth battery cell assembly as described in some embodiments of the present application;

[0030] Figure 11 A top view of a fifth battery cell assembly as described in some embodiments of the present application.

[0031] Specifically, the annotations of the figures in the specification are as follows:

[0032] 100, battery cell assembly; 110, positive electrode sheet; 120, negative electrode sheet; 130, separator; 140, conductive sheet; 141, conductive base material; 142, insulating adhesive coating; Q1, coating area; Q2, gap area; B, circular arc part; B1, first circular arc part; B2, second circular arc part; X, first direction; Y, second direction. DETAILED DESCRIPTION

[0033] In order to make the content of the embodiments of the present application more clear, the following will be described in conjunction with the figures in the specification. It can be understood that the following mentioned content is only some embodiments of the present application, and all the embodiments are enumerated in detail. Therefore, other embodiments obtained based on the following embodiments fall within the protection scope of the present application without creative labor.

[0034] It should be understood that the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the technical solutions. For example, the terms "one", "said" and "the" used herein to modify a feature do not exclude the possibility that the feature can be plural in other embodiments.

[0035] It should be understood that the terms "comprising", "including" and "having" are open and indicate the presence of the stated features but do not exclude the presence of other features. Similarly, the use of the terms first, second and the like to describe a plurality of features does not imply that the features are ordered in a specific order unless the context clearly indicates otherwise.

[0036] It should be understood that the terms "comprising", "including" and "having" are open and indicate the presence of the stated features but do not exclude the presence of other features. Similarly, the use of the terms first, second and the like to describe a plurality of features does not imply that the features are ordered in a specific order unless the context clearly indicates otherwise.

[0037] In addition, for the convenience of description, spatial relative terms will be used herein to describe the position of one feature relative to another feature, such as "inner", "outer", "end", "side", "upper", "middle", "lower", "high", "low", "axial", "circumferential", "radial", "horizontal", "vertical", "first direction", "second direction" and the like. It can be understood that the spatial relative relationship between two features should include other specific conditions other than those shown in the drawings.

[0038] The embodiments of the present application will be described below with reference to the drawings.

[0039] In the first aspect, with reference to Figures 1 to 11 The application provides an electric core assembly 100, which comprises a positive electrode sheet 110, a negative electrode sheet 120, a separator 130 and a conductive sheet 140. The separator 130 is located between the positive electrode sheet 110 and the negative electrode sheet 120, and the three are wound to form a roll core. The roll core has a circular arc part B, and the conductive sheet 140 is attached to the circular arc part B. The conductive sheet 140 comprises a conductive base material 141 and an insulating adhesive coating 142. The conductive base material 141 is provided with the insulating adhesive coating 142 on at least one side. The side of the conductive base material 141 provided with the insulating adhesive coating 142 is divided into a coating area Q1 and a gap area Q2.

[0040] The coating area Q1 is an area where the surface of the conductive substrate 141 is coated with the insulating adhesive coating 142, and the gap area Q2 is an area where the surface of the conductive substrate 141 is not coated with the insulating adhesive coating 142. Specifically, when the conductive sheet 140 is located at the outermost layer of the core, the side of the conductive substrate 141 facing the core can be coated with the insulating adhesive coating 142; when the conductive sheet 140 is located inside the core, both sides of the conductive substrate can be coated with the insulating adhesive coating 142.

[0041] In the present application, the conductive sheet 140 is attached to the breakable part of the electrode sheet of the battery cell, i.e. at least the outer layer of the core arc B. When the electrode sheet breaks, the conductive sheet 140 can act as a conductive bridge to ensure that the broken part of the electrode sheet can conduct electricity normally, thereby avoiding the problem of sudden capacity drop caused by the breakage of the electrode sheet, and ensuring the cycle performance of the battery. In addition, the insulating adhesive coating 142 is used instead of the conventional conductive adhesive layer for bonding, thereby avoiding the dissolution of metal particles in the conductive adhesive layer under the immersion of the electrolyte, which can cause internal short circuit of the battery. Furthermore, the insulating adhesive coating 142 is only coated on part of the area of the conductive substrate 141, which ensures the bonding strength while allowing the conductive substrate 141 to be in contact with the electrode sheet to achieve the effect of conduction.

[0042] It should be noted that the conductive sheet 140 of the present application can also use a combination of a conductive substrate 141 and a conductive adhesive coating, or a combination of a polymer substrate and a conductive adhesive coating. The conductive adhesive coating contains metal particles and has conductivity, so the conductive adhesive coating can cover the surface of the substrate without the need for direct contact between the substrate and the electrode sheet.

[0043] Further, the metal particles contained in the conductive adhesive coating can be any one or any combination of two or more of aluminum, copper, silver, gold, molybdenum, tungsten, zinc, nickel, iron, platinum, tin, and lead; and the material of the polymer substrate can be, but is not limited to, polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polytetrafluoroethylene, polyimide, polyamide, and silicone rubber.

[0044] In some embodiments, the electrical conductivity of the conductive substrate 141 is σ, and satisfies σ≥1*10 -2 S / m; and / or, the conductive substrate 141 is a metal foil, a composite foil composed of a polymer and a metal, or a carbon-based material. The metal foil and the metal element in the composite foil can be copper, aluminum, nickel, silver, iron, molybdenum, etc., the polymer in the composite foil can be polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, etc., and the carbon-based material can be carbon, graphene foil, carbon fiber cloth, etc.

[0045] It should be noted that since the insulating adhesive coating 142 on the conductive base material 141 is not conductive, but only plays a conductive role through the wire base material, the conductive base material 141 needs to have good conductivity, and the conductivity σ thereof should not be too large, for example, σ can be 0.01 S / m, 0.05 S / m, 0.08 S / m, 0.1 S / m, 0.5 S / m, 0.8 S / m, 1 S / m, 10 S / m, 1*10 2 S / m, 1*10 3 S / m, 1*10 4 S / m, 1*10 5 S / m, 1*10 6 S / m, 1*10 7 S / m, etc. In addition, the material of the insulating adhesive coating 142 can be, but is not limited to, a polymer such as polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polytetrafluoroethylene, polyimide, polyamide, silicone rubber, etc.

[0046] In some embodiments, the area of the coating region Q1 is S1, the area of the gap region Q2 is S2, and 20%≤S2 / (S1+S2)≤80% is satisfied.

[0047] In the above embodiments, for the single side of the conductive base material 141 coated with the insulating adhesive coating 142, the proportion of the area of the gap region Q2 to the total area of the side cannot be too small, otherwise the contact area of the conductive base material 141 with the pole piece will be small, and when the pole piece breaks, the conductive sheet 140 will be difficult to have good conductivity. At the same time, the proportion of the area of the gap region Q2 to the total area of the side cannot be too large, otherwise the area left for the coating region Q1 will be small, i.e., the insulating adhesive coating 142 will be less, and cannot have a good bonding effect, the connection between the conductive sheet 140 and the pole piece will not be firm, and is prone to falling off. Therefore, the proportion of the area of the gap region Q2 to the total area of the side should be moderate, i.e., S2 / (S1+S2) should be moderate, for example, S2 / (S1+S2) can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% any one value or a range between any two values.

[0048] In some embodiments, the thickness of the conductive sheet 140 is d, the thickness of the conductive base material 141 is d1, and the thickness of the insulating adhesive coating 142 is d2, and 8 μm≤d≤30 μm, 5 μm≤d1≤25 μm, 1 μm≤d2≤10 μm are satisfied.

[0049] In the above embodiments, the thickness of the conductive substrate 141, the thickness of the insulating adhesive coating 142, and the total thickness of the conductive sheet 140 formed by the two should be moderate, otherwise, if the thickness is too large, it occupies too much space inside the battery, easily extruding the pole piece, if the thickness is too small, it affects the overcurrent capacity, the conductivity is poor, and the strength is low, and it is easy to break.

[0050] In some embodiments, the thickness d1 of the conductive substrate 141 can be any one of 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm or a range between any two of them; the thickness d2 of the insulating adhesive coating 142 can be any one of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm or a range between any two of them; the thickness d of the conductive sheet 140 can be any one of 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm or a range between any two of them.

[0051] In some embodiments, the width of the conductive sheet 140 is W and satisfies 5 mm≤W≤30 mm.

[0052] In the above embodiments, the width of the conductive sheet 140 should also not be too small, otherwise it will affect the overcurrent capacity, the conductivity is poor, and the strength is low, and it is easy to break; at the same time, the width of the conductive sheet 140 should also not be too large, otherwise it may exceed the width of the pole piece too much and wrap multiple pole pieces along the thickness direction of the pole piece, causing internal short circuit of the battery. Therefore, the width W of the conductive sheet 140 should be moderate, for example, W can be any one of 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm or a range between any two of them.

[0053] In some embodiments, with reference to Figures 1 to 6 , the coating area Q1 is a regular shape or an irregular shape, and / or the gap area Q2 is continuously distributed or spaced.

[0054] It can be understood that, asFigure 1 and Figure 2 As shown, the coating area Q1 is rectangular and continuously distributed along the length direction of the conductive substrate 141, and spaced apart along the width direction of the conductive substrate 141; as Figure 3 As shown, the coating area Q1 is rectangular and is spaced apart along the length direction of the conductive substrate 141 and continuously distributed along the width direction of the conductive substrate 141; as Figure 4 As shown, the coating area Q1 is rectangular and is spaced apart along both the length and width directions of the conductive substrate 141; as Figure 5 As shown, the coating area Q1 is a combination of circles and ellipses, and is distributed at intervals along both the length and width directions of the conductive substrate 141; as Figure 6 As shown, the coating area Q1 has an irregular shape and is continuously distributed along both the length and width directions of the conductive substrate 141. The above is an exemplary demonstration of the coating area Q1 and does not limit the specific style of the coating area Q1. All styles of coating areas Q1 that conform to the inventive concept of this application are within the protection scope of this application.

[0055] In some embodiments, the coating areas Q1 are of a regular shape and are spaced apart, and the distance between adjacent coating areas Q1 is D, satisfying 1mm≤D≤10mm.

[0056] In the above embodiments, the distance D between adjacent coating areas Q1 should be moderate. Otherwise, if it is too small, the area left for the gap area Q2 will be small, that is, the contact area between the conductive substrate 141 and the electrode will be small, affecting the conductivity. If it is too large, it will result in low bonding strength, and the conductive substrate 141 will not be firmly connected to the electrode, making it easy to fall off. Therefore, in some embodiments, the distance D between adjacent coating areas Q1 can be any one of 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, and 10mm, or a range between any two of these values.

[0057] In some embodiments, the coating area Q1 is irregular in shape and satisfies S2≥2mm 2 .

[0058] In the above embodiment, the area of ​​the coating region Q1 should be moderate. Otherwise, if it is too small, the bonding strength will be low, the conductive substrate 141 will not be firmly connected to the electrode, and it will easily fall off. If it is too large, the area left for the gap region Q2 will be small, that is, the contact area between the conductive substrate 141 and the electrode will be small, affecting the conductivity. Therefore, the area S2 of the coating region Q1 can be 2 mm. 2 3mm 2 4mm 2 5mm 2 6mm 2 7mm2 8mm 2 9mm 2 10mm 2 etc.

[0059] In some embodiments, with reference to Figures 7 to 11 The arc portion B includes a first arc portion B1 and a second arc portion B2 located at both ends of the core in the first direction X, and at least one of the first arc portion B1 and the second arc portion B2 is provided with the conductive sheet 140. In some embodiments, the first arc portion B1 and the second arc portion B2 each have multiple arc layers in the first direction X, and at least one arc layer of the first arc portion B1 and / or the second arc portion B2 is provided with the conductive sheet 140.

[0060] It should be noted that the first direction X is the length direction of the core, and the second direction Y is the thickness direction of the core, and the first direction X and the second direction Y are perpendicular to each other.

[0061] In practice, the negative electrode sheet 120 is mostly made of silicon-based materials to improve the lithium intercalation capacity, but the negative electrode sheet 120 is prone to expand after intercalating lithium, thereby pressing the positive electrode sheet 110, and due to the stress concentration of the arc portion B of the positive electrode sheet 110, the positive electrode sheet 110 is prone to breakage; in addition, the inner circle layer of the positive electrode sheet 110 is coated with positive active material on both sides to form a double-sided area, and the outer circle layer is only coated with active material on one side to form a single-sided area, and the structural strength of the single-sided area is less than that of the double-sided area; therefore, the most prone to breakage in the battery core assembly 100 is the arc portion B of the single-sided area of the positive electrode sheet 110.

[0062] As can be understood, as shown in Figure 7 The outer side of the outermost arc layer of the first arc portion B1, i.e., the outer side of the left part of the outermost circle of the positive electrode sheet 110, is attached with the conductive sheet 140. As shown in Figure 8 The outer side of the outermost arc layer of the second arc portion B2, i.e., the outer side of the right part of the outermost circle of the positive electrode sheet 110, is attached with the conductive sheet 140. As shown in Figure 9 The outer side of the outermost arc layer of the first arc portion B1 and the second arc portion B2, i.e., the outer side of the left part and the right part of the outermost circle of the positive electrode sheet 110, is attached with the conductive sheet 140. As shown in Figure 10 The inner and outer sides of the outermost arc layer of the first arc portion B1, i.e., the inner and outer sides of the left part of the outermost circle of the positive electrode sheet 110, are attached with the conductive sheet 140. As shown in Figure 11As shown, the outermost layer of the first arc part B1 and the outer side of the second outer arc layer, i.e. the outer side of the outermost circle and the left part of the second outer circle of the positive plate 110, are attached with the conductive sheet 140. The above is an exemplary display of the attachment position of the conductive sheet 140, and cannot be understood as a specific limitation on the attachment position of the conductive sheet 140. The conductive sheet 140 at various attachment positions in accordance with the inventive concept of the present application is within the scope of protection of the present application.

[0063] In a second aspect, the present application provides a battery comprising the cell assembly 100 of the first aspect.

[0064] Therefore, the battery of the second aspect has at least all the technical effects of the cell assembly 100 of the first aspect, and the specific technical effects will not be described here. In addition, the embodiments of the present application only illustrate the structures of the battery of the second aspect related to the improvement points of the present application, but do not mean that it does not have other structures. For example, the battery also includes a shell, a cover plate and the like, and other structures will not be described here.

[0065] In particular, the term "and / or" in the present application should be understood as follows:

[0066] In the first case, the term "and / or" between the first subject and the second subject includes any of the following meanings: (1) only the first subject; (2) only the second subject; and (3) the first subject and the second subject.

[0067] In the second case, the term "and / or" between the last two subjects among three or more subjects means to include at least any one of the plurality of subjects. For example, "the first subject, the second subject and / or the third subject" has the same meaning as "the first subject and / or the second subject and / or the third subject", which specifically includes the following combinations: (1) only the first subject; (2) only the second subject; (3) only the third subject; (4) the first subject and the second subject without the third subject; (5) the first subject and the third subject without the second subject; (6) the second subject and the third subject without the first subject; and (7) the first subject, the second subject and the third subject.

[0068] In addition, the character " / " in the present application generally represents an "or" relationship between the associated objects before and after it.

[0069] Finally, although the above describes the embodiments of the present application in conjunction with the drawings, those skilled in the art can make various modifications and variations without departing from the concept of the present application, and such modifications and variations are also within the scope of protection of the present application.

Claims

1. An electrochemical cell assembly, comprising: The battery includes a positive electrode sheet (110), a negative electrode sheet (120), a separator (130), and a conductive sheet (140), the separator (130) is located between the positive electrode sheet (110) and the negative electrode sheet (120), and the three are wound to form a roll core, the roll core has a circular arc part (B), and the conductive sheet (140) is attached to the circular arc part (B); The conductive sheet (140) includes a conductive base material (141) and an insulating adhesive coating (142), a part of an area on at least one side of the conductive base material (141) is provided with the insulating adhesive coating (142), and the side of the conductive base material (141) provided with the insulating adhesive coating (142) is divided into a coating area (Q1) and a gap area (Q2).

2. The cell assembly of claim 1, wherein, The electric conductivity of the conductive substrate (141) is σ, and satisfies σ≥1*10 -2 S / m; And / or, the conductive base material (141) is a metal foil, a composite foil composed of metal and polymer, or a carbon-based material.

3. The cell assembly of claim 1, wherein, The area of the coating area (Q1) is S1, the area of the gap area (Q2) is S2, and 20%≤S2 / (S1+S2)≤80% is satisfied.

4. The cell assembly of claim 3, wherein, The coating area (Q1) is a regular shape or an irregular shape, and / or the gap area (Q2) is continuously distributed or spaced.

5. The cell assembly of claim 4, wherein, The coating area (Q1) is a regular shape and is spaced, the distance between adjacent coating areas (Q1) is D, and 1mm≤D≤10mm is satisfied.

6. The cell assembly of claim 4, wherein, The coating region (Q1) is irregularly shaped and satisfies S2≥2mm 2 .

7. The cell assembly of any one of claims 1 to 6, wherein, The circular arc part (B) includes a first circular arc part (B1) and a second circular arc part (B2) located at both ends of the roll core in the first direction (X), and at least one of the first circular arc part (B1) and the second circular arc part (B2) is provided with the conductive sheet (140).

8. The cell assembly of claim 7, wherein, The first circular arc part (B1) and the second circular arc part (B2) have a plurality of circular arc layers in the first direction (X) respectively, and at least one of the circular arc layers of the first circular arc part (B1) and / or the second circular arc part (B2) is provided with the conductive sheet (140).

9. The cell assembly of any one of claims 1 to 6, wherein, The thickness of the conductive sheet (140) is d, the thickness of the conductive base material (141) is d1, and the thickness of the insulating adhesive coating (142) is d2, and 8μm≤d≤30μm, 5μm≤d1≤25μm, and 1μm≤d2≤10μm are satisfied.

10. The cell assembly of any one of claims 1 to 6, wherein, The width of the conductive sheet (140) is W, and 5mm≤W≤30mm is satisfied.

11. A battery, characterized by The battery includes the cell assembly (100) of any one of claims 1 to 10.

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