Battery cell, battery and battery cell manufacturing method

Abstract

The invention relates to a battery cell, a battery and a battery cell manufacturing method. In the battery cell, electrode plates are stacked; the diaphragm is stacked between two adjacent electrode plates; the diaphragm and the electrode plates are wound to form a roll core; the electrode plate is provided with a tab part protruding out of the diaphragm, and the tab part is arranged on the end face of the roll core in a bent mode so as to form a tab end face on the end face of the roll core; the winding tail end of the diaphragm is provided with an extension part, and the extension part is arranged on the end face of the tab in a bending manner and covers at least part of the end face of the tab, so that the tab part is isolated from the shell, the tab part of the electrode plate is insulated, the tab part is prevented from being in contact with the shell, an extra insulating part does not need to be arranged on the tab part, and the cost is reduced. The tab insulation structure of the battery cell is simplified, the reliability of the battery cell is improved, and the manufacturing efficiency of the battery can be improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and a method for manufacturing the battery cell. Background Art

[0002] The cylindrical battery consists of a shell, a positive electrode sheet, a negative electrode sheet and a separator. The manufacturing process of the cylindrical battery involves winding technology, that is, with a winding needle as the core, the positive electrode sheet, the separator and the negative electrode sheet are stacked and wound together by driving the winding needle to rotate to form a cylindrical winding core, and the winding core is placed in the shell to obtain a cylindrical battery.

[0003] The winding core leads out the electrodes by respectively setting tabs on the positive and negative electrode sheets. After the winding core is loaded into the shell and the electrodes of the winding core are connected to the shell, in order to prevent the tabs of the winding core from contacting with the shell and causing a short circuit, an insulating part is usually set on the end face of the tab of the winding core. The insulating part insulates the end face of the tab from the shell to achieve the effect of preventing short circuit. However, this structure is more complicated and requires additional insulating parts, which increases the difficulty of manufacturing the battery. Summary of the invention

[0004] Based on this, a battery cell, a battery and a method for manufacturing the battery cell are provided.

[0005] In a first aspect, the present application provides a battery cell, comprising:

[0006] A pole piece group, the pole piece group includes at least two electrode pieces, each electrode piece is stacked;

[0007] A diaphragm, which is stacked between two adjacent electrode sheets; the diaphragm and the electrode sheets are wound to form a winding core;

[0008] The electrode sheet is provided with a pole ear portion protruding from the diaphragm, and the pole ear portion is bent and arranged on the end face of the winding core to form a pole ear end face on the end face of the winding core; an extension portion is provided at the winding end of the diaphragm, and the extension portion is bent and arranged on the pole ear end face to cover at least part of the pole ear end face to isolate the pole ear portion from the shell.

[0009] In one embodiment, the extension portion includes a connecting portion and a protruding portion;

[0010] The connecting portion is connected to the winding end of the diaphragm, the protruding portion is connected to the connecting portion, the protruding portion protrudes from the corresponding pole ear end surface along the axial direction of the winding core, and the protruding portion is bent and arranged on the pole ear end surface.

[0011] In one embodiment, the protrusion includes at least two protrusion sub-parts; and there is a gap between two adjacent protrusion sub-parts.

[0012] In one embodiment, the length of the slit is less than or equal to the protruding length of the corresponding protruding sub-portion.

[0013] In one embodiment, the length of the connecting portion along the winding direction is less than or equal to the length of the diaphragm along the winding direction;

[0014] The length of the protrusion along the winding direction is less than or equal to the length of the diaphragm along the winding direction.

[0015] In one embodiment, the length of the extension portion is greater than or equal to the length of one circle of the winding core starting from the winding end of the winding core.

[0016] In one embodiment, the length of the extension portion is greater than or equal to the length of two turns of the winding core starting from the winding end of the winding core.

[0017] In one of the embodiments, the extension portion is provided with at least one first through hole; the first through hole is used to pass the electrical connector to connect the pole ear portion to the electrical connector.

[0018] In one embodiment, a winding start end of the separator protrudes beyond a winding start end of an adjacent electrode sheet.

[0019] In one embodiment, the length of the winding start end of the separator protruding from the winding start end of the adjacent electrode sheet is greater than twice the circumference of the winding needle.

[0020] In one embodiment, the electrode sheet group includes a first electrode sheet and a second electrode sheet adjacent to each other;

[0021] The first electrode sheet is provided with a first pole ear portion protruding from the diaphragm, and the first pole ear portion is bent and arranged on the first end face of the winding core to form a first pole ear end face on the end face of the winding core; the second electrode sheet is provided with a second pole ear portion protruding from the diaphragm, and the second pole ear portion is bent and arranged on the second end face of the winding core to form a second pole ear end face on the end face of the winding core;

[0022] A first extension portion is provided at the winding end of the diaphragm, and the first extension portion is bent and arranged on the end surface of the first pole lug to cover at least a portion of the end surface of the first pole lug;

[0023] And / or, a second extension portion is provided at the winding end of the separator, and the second extension portion is bent and provided on the second pole lug end surface to cover at least a portion of the second pole lug end surface.

[0024] In a third aspect, the present application provides a battery, comprising a housing, a cover assembly, and a battery cell as described above;

[0025] The housing is provided with at least one opening, the battery cell is provided in the housing, and the cover assembly is used to cover each opening. In one embodiment, a current collector is provided between the end face of the pole lug and the protrusion, the current collector is electrically connected to the corresponding end face of the pole lug, and the protrusion at least partially abuts against the current collector;

[0026] The cover assembly is electrically connected to the corresponding current collector; or the shell is electrically connected to the corresponding current collector.

[0027] In one embodiment, the shell is provided with a necked portion adjacent to the opening, and the necked portion is located between the cover assembly and the protruding portion.

[0028] In one embodiment, the retracted depth of the constricted portion is less than the protruding length of the protruding portion;

[0029] Alternatively, a projection of the necked portion on the protruding portion along the axial direction of the winding core is located within an end surface of the protruding portion.

[0030] In one embodiment, the battery further includes a first pole; a first pole hole is provided at the bottom of the shell; one end of the first pole passes through the first pole hole and is electrically connected to the corresponding current collector;

[0031] And / or, the battery cell further includes a second pole; the cover assembly is provided with a second pole hole; one end of the second pole passes through the second pole hole and is electrically connected to the corresponding current collector.

[0032] In one embodiment, the cover plate assembly includes a first cover plate; a first opening is provided on the top of the housing, and the first cover plate covers the first opening;

[0033] And / or, the cover plate assembly further includes a second cover plate; a second opening is provided at the bottom of the shell, and the second cover plate covers the second opening.

[0034] In one embodiment, a first insulating member is disposed between the first pole and the housing; and / or a second insulating member is disposed between the first cover plate and the housing.

[0035] In one embodiment, a third insulating member is disposed between the second pole and the housing; and / or a fourth insulating member is disposed between the second cover plate and the housing.

[0036] In a fourth aspect, the present application provides a method for manufacturing a battery cell, which is applied to any of the above-mentioned battery cells, and the method for manufacturing a battery cell comprises the following steps:

[0037] Providing at least one diaphragm and at least two electrode sheets;

[0038] cutting the wound end of the diaphragm to form an extension;

[0039] The electrode sheet is provided with a pole ear portion protruding from the diaphragm;

[0040] The cut separator is stacked between two adjacent electrode sheets, and the stacked electrode sheets and separator are wound to form a winding core;

[0041] The pole ear portion is bent and arranged on the end surface of the winding core to form a pole ear end surface on the end surface of the winding core;

[0042] The extension portion is bent and arranged on the end surface of the pole lug to cover at least a portion of the end surface of the pole lug, so as to isolate the pole lug portion from the shell.

[0043] In one embodiment, the step of providing the electrode sheet with a lug portion protruding from the diaphragm comprises:

[0044] The electrode sheet is divided into a coated area and an uncoated area, wherein the uncoated area protrudes from the diaphragm;

[0045] The active material is coated on the coated area to form an active material layer; and the uncoated area is cut to form a pole ear portion.

[0046] In one embodiment, the step of bending the extension portion and arranging it on the end surface of the pole lug to cover at least a portion of the end surface of the pole lug so as to isolate the pole lug portion from the housing includes:

[0047] A current collector is arranged on the end surface of the pole lug to electrically connect the end surface of the pole lug to the current collector;

[0048] The extension part is bent and arranged on the current collecting member to cover at least a part of the current collecting member.

[0049] One of the above technical solutions has the following advantages and beneficial effects:

[0050] The above-mentioned battery cell includes a pole piece group and a diaphragm, the pole piece group includes at least two electrode sheets, each electrode sheet is stacked; the diaphragm is stacked between two adjacent electrode sheets; the diaphragm and each electrode sheet are wound to form a winding core; the electrode sheet is provided with a pole ear portion protruding from the diaphragm, the pole ear portion is bent and arranged on the end face of the winding core to form a pole ear end face on the end face of the winding core; the winding end of the diaphragm is provided with an extension portion, the extension portion is bent and arranged on the pole ear end face, covering at least part of the pole ear end face to isolate the pole ear portion from the shell, thereby realizing the insulation setting of the pole ear portion of the electrode sheet and avoiding the contact between the pole ear portion and the shell to cause a short circuit. The present application provides an extension portion on the diaphragm. When the pole piece group and the diaphragm are wound to form a core, the extension portion can be bent toward the core of the core, and at least part of the extension portion covers the end face of the pole ear, thereby achieving insulation of the pole ear and preventing the pole ear from contacting the shell. There is no need to additionally provide an insulating part for the pole ear, which simplifies the pole ear insulation structure of the battery cell, improves the reliability of the battery cell, and can improve the manufacturing efficiency of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a schematic diagram of the structure of the battery cell in the embodiment of the present application;

[0052] Figure 2 is a cross-sectional schematic diagram of a battery cell in an embodiment of the present application;

[0053] Figure 3This is a schematic diagram of a first exploded structure of a battery cell in an embodiment of the present application;

[0054] Figure 4 This is a schematic diagram of a second exploded structure of a battery cell in an embodiment of the present application;

[0055] Figure 5 This is a schematic diagram of a third exploded structure of a battery cell in an embodiment of the present application;

[0056] Figure 6 This is a schematic diagram of a first exploded structure of a battery in an embodiment of the present application;

[0057] Figure 7 for Figure 6 A schematic diagram of the enlarged structure at A in the middle;

[0058] Figure 8 This is a schematic diagram of a second exploded structure of a battery in an embodiment of the present application;

[0059] Fig. 9 for Figure 8 A schematic diagram of the enlarged structure at B in the middle;

[0060] Fig.10 This is a schematic diagram of a third exploded structure of a battery in an embodiment of the present application;

[0061] Fig.11 Schematic diagram of the process of manufacturing a battery cell in an embodiment of the present application.

[0062] Reference numerals:

[0063] 10. Battery cell; 100. Electrode sheet group; 102. Electrode sheet; 1022. First electrode sheet; 1024. Second electrode sheet; 106. Ear end face; 1062. First ear end face; 1064. Second ear end face; 110. Diaphragm; 112. Extension portion; 114. Connecting portion; 116. Protrusion; 1162. Protruding sub-portion; 20. Shell; 210. Narrowing portion; 310. First cover plate; 320. Second cover plate; 40. Current collector; 510. First pole; 520. Second pole; 610. First insulating member; 620. Second insulating member; 630. Third insulating member; 640. Fourth insulating member. DETAILED DESCRIPTION

[0064] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0065] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0066] In addition, the term "plurality" shall mean two or more.

[0067] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0068] In one embodiment, Figures 1 to 3 As shown, a battery cell is provided, including a pole piece group 100 and a diaphragm 110, the pole piece group 100 includes at least two electrode sheets 102, and each electrode sheet 102 is stacked; the diaphragm 110 is stacked between two adjacent electrode sheets 102; the diaphragm 110 and each electrode sheet 102 are wound to form a winding core; the electrode sheet 102 is provided with a pole ear portion protruding from the diaphragm 110, and the pole ear portion is bent and arranged on the end face of the winding core to form a pole ear end face 106 on the end face of the winding core; the winding end of the diaphragm 110 is provided with an extension portion 112, and the extension portion 112 is bent and arranged on the pole ear end face 106 to cover at least part of the pole ear end face 106 to isolate the pole ear portion from the shell 20.

[0069] The electrode sheet group 100 is composed of at least two electrode sheets 102, each of which includes at least one positive electrode sheet and at least one negative electrode sheet. The electrode sheet 102 may be in the form of a rectangular sheet, and the electrode sheet 102 has a winding start end and a winding end opposite to each other, and the electrode sheet 102 also has a top end and a bottom end adjacent to the winding start end. The top or bottom end of the electrode sheet 102 is provided with a pole ear portion protruding from the diaphragm 110, and the pole ear portion and the corresponding electrode sheet 102 may be an integrally formed structure. Exemplarily, the active material may not be coated on the area of ​​the electrode sheet 102 protruding from the diaphragm 110, and then the pole ear portion is formed in the area of ​​the electrode sheet 102 protruding from the diaphragm 110.

[0070] The diaphragm 110 is used to isolate two adjacent electrode sheets 102. For example, the diaphragm 110 can be stacked between adjacent positive and negative electrode sheets to insulate and isolate the positive and negative electrode sheets to prevent the positive and negative electrode sheets from contacting and short-circuiting. The diaphragm 110 can be in the shape of a rectangular sheet. The diaphragm 110 has a relative winding start end and a winding end. The diaphragm 110 also has a top and a bottom adjacent to the winding start end. The winding end of the diaphragm 110 can be provided with an extension 112, and the extension 112 and the corresponding diaphragm 110 can be an integrally formed structure. The extension 112 and the diaphragm 110 can be made of the same material or different materials. The extension 112 can be made of a heat-shrinkable material, and the extension is formed by heat shrinking and covered on the end face 106 of the pole ear. Exemplarily, the extension 112 can be formed by cutting the winding end of the diaphragm 110. The extension portion 112 may be disposed adjacent to the top end or the bottom end of the diaphragm 110 . In another example, the extension portion 112 is disposed adjacent to the top end and the bottom end of the diaphragm 110 , respectively.

[0071] The electrode sheets 102 and the diaphragms 110 are stacked, and based on the winding starting ends of the electrode sheets 102 and the diaphragms 110, the diaphragms 110 and the electrode sheets 102 are wound to form a winding core, and the extension portion 112 of the diaphragm 110 is continuously wound so that the extension portion 112 covers the outside of the electrode sheet 102; the pole ear portion is bent and arranged on the corresponding end face of the winding core, and then the pole ear end face 106 is formed on the corresponding end face of the winding core; the extension portion 112 is bent and arranged on the pole ear end face 106, and covers at least part of the pole ear end face 106, so that when the battery cell 10 is installed in the shell 20, the pole ear portion of the electrode sheet 102 can be insulated and isolated from the shell 20 by the extension portion 112 of the diaphragm 110, so as to prevent the pole ear of the battery cell 10 from contacting with the shell 20 and causing a short circuit.

[0072] In the above-mentioned embodiment, the electrode sheets 102 are stacked; the diaphragm 110 is stacked between two adjacent electrode sheets 102; the diaphragm 110 and the electrode sheets 102 are wound to form a winding core; the electrode sheet 102 is provided with a pole ear portion protruding from the diaphragm 110, and the pole ear portion is bent and arranged on the end face of the winding core to form a pole ear end face 106 on the end face of the winding core; the winding end of the diaphragm 110 is provided with an extension portion 112, and the extension portion 112 is bent and arranged on the pole ear end face 106 to cover at least part of the pole ear end face 106 to isolate the pole ear portion from the shell 20, thereby realizing the insulation setting of the pole ear portion of the electrode sheet 102 and avoiding the pole ear portion from contacting the shell 20 and causing a short circuit. The present application provides an extension portion 112 on the diaphragm 110. When the pole piece group 100 and the diaphragm 110 are wound to form a winding core, the extension portion 112 can be bent toward the core direction of the winding core, and at least a portion of the extension portion 112 covers the pole ear end surface 106, thereby achieving insulation of the pole ear portion and preventing the pole ear portion from contacting the shell 20. There is no need to additionally provide an insulating part for the pole ear portion, which simplifies the pole ear insulation structure of the battery cell 10, improves the reliability of the battery cell 10, and can improve the manufacturing efficiency of the battery.

[0073] In one embodiment, Figure 1 and Figure 4 As shown, the extension portion 112 includes a connecting portion 114 and a protrusion 116; the connecting portion 114 is connected to the winding end of the diaphragm 110, and the protrusion 116 is connected to the connecting portion 114, and the protrusion 116 protrudes from the corresponding pole ear end face 106 along the axial direction of the winding core, and the protrusion 116 is bent and set on the pole ear end face 106.

[0074] The connection portion 114 and the protrusion 116 are an integrally formed structure, and the connection portion 114 and the diaphragm 110 are an integrally formed structure. The connection portion 114 may be disposed adjacent to the top or bottom end of the diaphragm 110; in another example, the connection portion 114 is disposed adjacent to the top and bottom ends of the diaphragm 110, respectively. The protrusion 116 protrudes from the top or bottom end of the diaphragm 110, that is, when each electrode sheet 102 and the diaphragm 110 are wound to form a winding core, the protrusion 116 protrudes from the corresponding pole ear end face 106 along the axial direction of the winding core. The protrusion 116 may be bent and disposed on the corresponding pole ear end face 106 by bonding.

[0075] Illustratively, a first pole lug end face 1062 is disposed at the top of the winding core, a second pole lug end face 1064 is disposed at the bottom of the winding core, a first connecting portion 114 and a first protrusion 116 are disposed adjacent to the first pole lug end face 1062 , and a second connecting portion 114 and a second protrusion 116 are disposed adjacent to the second pole lug end face 1064 .

[0076] The separator 110 and each electrode sheet 102 are wound to form a winding core based on the winding starting end of each electrode sheet 102 and the winding starting end of the separator 110, and the first connecting portion 114 and the second connecting portion 114 of the separator 110 are continuously wound so that the first connecting portion 114 covers the outer side surface adjacent to the top end of the electrode sheet 102, and the second connecting portion 114 covers the outer side surface adjacent to the bottom end of the electrode sheet 102; the first protrusion 116 is bent and arranged on the first pole ear end surface 1062, and covers at least a portion of the first pole ear end surface 1062, The second protrusion 116 of the component is bent and arranged on the second pole ear end surface 1064, and covers at least a portion of the second pole ear end surface 1064. Therefore, when the battery cell 10 is installed in the shell 20, the pole ear portion of the electrode sheet 102 can be insulated and isolated from the shell 20 through the corresponding extension portion 112 of the diaphragm 110, so as to prevent the pole ear of the battery cell 10 from contacting with the shell 20 and causing a short circuit. There is no need to additionally arrange an insulating component on the pole ear portion, so that the battery cell 10 has a self-insulating structure, which simplifies the pole ear insulation structure of the battery cell 10 and improves the reliability of the battery cell 10.

[0077] In one embodiment, Figure 4 and Figure 5 As shown, the protrusion 116 includes at least two protrusion sub-parts 1162 ; there is a gap between two adjacent protrusion sub-parts 1162 .

[0078] The protrusion 116 can be divided into at least two protrusion sub-parts 1162. For example, the shapes and sizes of the protrusion sub-parts 1162 are the same; in another example, the shapes and sizes of the protrusion sub-parts 1162 can be different, and the shapes and sizes of the protrusion sub-parts 1162 can be specifically set according to the requirements of the bending setting. By setting a gap between two adjacent protrusion sub-parts 1162, each protrusion sub-part 1162 can be bent toward the end face 106 of the lug of the winding core.

[0079] In one embodiment, the length of the slit is less than or equal to the protruding length of the corresponding protruding sub-portion 1162 .

[0080] For example, the corresponding protrusion 116 can be cut along the axial direction of the winding core to form at least one slit on the protrusion 116, thereby dividing the protrusion 116 into at least two protrusion sub-parts 1162. By setting the length of the slit to be less than or equal to the protrusion length of the corresponding protrusion sub-part 1162, when each protrusion sub-part 1162 is bent, the electrode sheet 102 is prevented from being exposed from the connection position between the corresponding connection part 114 and the protrusion 116, thereby preventing the electrode sheet 102 from contacting the shell 20 when the battery cell 10 is installed in the shell 20, thereby further improving the safety of the battery cell 10.

[0081] In one embodiment, the length of the connecting portion 114 along the winding direction is less than or equal to the length of the diaphragm 110 along the winding direction; the length of the protruding portion 116 along the winding direction is less than or equal to the length of the diaphragm 110 along the winding direction.

[0082] The length of the connecting portion 114 along the winding direction may be equal to the length of the protruding portion 116 along the winding direction.

[0083] By setting the length of the connecting portion 114 along the winding direction to be less than or equal to the length of the diaphragm 110 along the winding direction, after each electrode sheet 102 and the diaphragm 110 are wound to form a winding core, the connecting portion 114 can be wound to cover the outer periphery of the winding core, thereby avoiding the connection portion 114 being too long and causing material waste. By setting the length of the protruding portion 116 along the winding direction to be less than or equal to the length of the diaphragm 110 along the winding direction, after each electrode sheet 102 and the diaphragm 110 are wound to form a winding core, the protruding portion 116 can be bent and covered around the lug end surface 106 of the winding core, thereby avoiding the protruding portion 116 being too long and causing material waste.

[0084] In one embodiment, the length of the extension portion 112 is greater than or equal to the length of one circle of the winding core starting from the winding end of the winding core.

[0085] The winding end of the winding core refers to the winding end of the diaphragm 110 or the electrode sheet 102. The length of the extension portion 112 refers to the length of the extension portion 112 along the winding direction. By setting the length of the extension portion 112 to be greater than or equal to the length of one circle of the winding core starting from the winding end of the winding core, the extension portion 112 can be wound to completely cover the outer circumference of the winding core, thereby preventing the side of the electrode sheet 102 from contacting the housing 20.

[0086] Exemplarily, the length of the extension 112 is greater than or equal to the length of two turns of the winding core starting from the winding end of the winding core. Furthermore, the gap on the protrusion 116 close to the core does not overlap with the gap on the protrusion 116 away from the core, so that the outer ring protrusion 116 can cover the gap on the inner ring protrusion 116, preventing the protrusion 116 from bending and exposing the gap of the electrode sheet 102, improving the insulation effect of the pole ear portion of the electrode sheet 102, preventing the pole ear portion from contacting the housing 20, and improving the reliability of the battery cell 10.

[0087] In one embodiment, the extension portion 112 is provided with at least one first through hole; the first through hole is used to pass the electrical connector to connect the pole ear portion to the electrical connector.

[0088] A first through hole may be provided in the protruding portion 116 of the extending portion 112 , and the electrical connector passes through the first through hole and is welded to the corresponding pole ear portion, so that the corresponding pole ear portion is led out as an electrode.

[0089] In one embodiment, a winding start end of the separator 110 protrudes beyond a winding start end of an adjacent electrode sheet 102 .

[0090] The winding start end of the separator 110 and the winding start end of the electrode sheet 102 can be wound based on a winding needle to form a winding core. By setting the winding start end of the separator 110 to protrude from the winding start end of the adjacent electrode sheet 102, when each electrode sheet 102 and the separator 110 are wound, the core of the winding core has the separator 110, which plays an insulating role for the winding start end of the winding core, thereby improving the insulation isolation effect between two adjacent electrode sheets 102.

[0091] In one embodiment, the length of the winding start end of the separator 110 protruding from the winding start end of the adjacent electrode sheet 102 is greater than twice the circumference of the winding needle.

[0092] By setting the length of the winding start end of the separator 110 protruding from the winding start end of the electrode sheet 102 to be at least twice the circumference of the winding needle, the insulation effect on the core of the winding core can be further strengthened, thereby improving the reliability of the battery cell 10.

[0093] In one embodiment, Figure 3 and Figure 5 As shown, the electrode sheet group 100 includes adjacent first electrode sheets 1022 and second electrode sheets 1024; the first electrode sheet 1022 is provided with a first pole ear portion protruding from the diaphragm 110, and the first pole ear portion is bent and arranged on the first end face of the winding core to form a first pole ear end face 1062 on the end face of the winding core; the second electrode sheet 1024 is provided with a second pole ear portion protruding from the diaphragm 110, and the second pole ear portion is bent and arranged on the second end face of the winding core to form a second pole ear end face 1064 on the end face of the winding core; the winding end of the diaphragm 110 is provided with a first extension portion 112, and the first extension portion 112 is bent and arranged on the first pole ear end face 1062 to cover at least a portion of the first pole ear end face 1062; and / or, the winding end of the diaphragm 110 is provided with a second extension portion 112, and the second extension portion 112 is bent and arranged on the second pole ear end face 1064 to cover at least a portion of the second pole ear end face 1064.

[0094] The first electrode sheet 1022 may be a positive electrode sheet, and the second electrode sheet 1024 may be a negative electrode sheet; accordingly, the first pole ear portion is a positive pole ear, and the second pole ear portion is a negative pole ear; the first pole ear end face 1062 is a positive pole ear end face 106, and the second pole ear end face 1064 is a negative pole ear end face 106. The extension portion 112 may be divided into a first extension portion 112 and a second extension portion 112.

[0095] The first electrode sheet 1022 includes a first active material portion coated with an active material layer along the winding direction and a first uncoated portion that is not coated with the active material layer and exposed outside the separator 110, that is, the first uncoated portion is a first pole ear portion, and the first uncoated portion is bent along the radial direction of the winding core to form a first pole ear end face 1062. The second electrode sheet 1024 includes a second active material portion coated with an active material layer along the winding direction and a second uncoated portion that is not coated with the active material layer and exposed outside the separator 110, that is, the second uncoated portion is a second pole ear portion, and the second uncoated portion is bent along the radial direction of the battery cell 10 to form a second pole ear end face 1064.

[0096] The diaphragm 110 is stacked between the adjacent first electrode sheets 1022 and the second electrode, and the stacked first electrode, the diaphragm 110 and the second electrode are wound to form a winding core; the first extension portion 112 and the second extension portion 112 of the diaphragm 110 are continuously wound so that the first extension portion 112 is disposed adjacent to the outer covering of one end of the winding core, and the second extension portion 112 is disposed adjacent to the outer covering of the other end of the winding core; the first pole ear portion and the second pole ear portion are bent and disposed on the corresponding end faces of the winding core, thereby forming the first pole ear end face 1062 and the second pole ear end face 1064 on the corresponding end faces of the winding core; the first extension portion 112 is bent and disposed on the first pole ear end face 1062, the second extension portion 112 is bent and arranged on the second pole ear end face 1064, and covers at least a portion of the first pole ear end face 1062 and at least a portion of the second pole ear end face 1064. Therefore, when the battery cell 10 is installed in the shell 20, the first extension portion 112 and the second extension portion 112 of the diaphragm 110 can insulate and isolate the first pole ear portion and the second pole ear portion of the electrode sheet 102 from the shell 20, thereby preventing the pole ear of the battery cell 10 from contacting the shell 20 and causing a short circuit, and there is no need to additionally set an insulating part on the pole ear of the battery cell 10, which simplifies the pole ear insulation structure of the battery cell 10, improves the reliability of the battery cell 10, and can improve the manufacturing efficiency of the battery.

[0097] In one embodiment, Figure 6 , Figure 8 and Fig.10 As shown, a battery is also provided, including a shell 20, a cover assembly and a battery cell 10 as described above; the shell 20 is provided with at least one opening, the battery cell 10 is arranged in the shell 20, and the cover assembly is used to cover each opening.

[0098] The housing 20 may be, but is not limited to, an aluminum housing. The housing 20 specifically includes a receiving cavity and at least one opening, the opening being connected to the receiving cavity. The battery cell 10 is disposed in the receiving cavity, and the cover assembly is used to cover the opening, thereby achieving position limiting and fixing of the battery cell 10.

[0099] The battery cell 10 includes an electrode sheet group 100 and a diaphragm 110. The electrode sheet group 100 includes at least two electrode sheets 102, which are stacked by each electrode sheet 102; the diaphragm 110 is stacked between two adjacent electrode sheets 102; the diaphragm 110 and each electrode sheet 102 are wound to form a winding core; the electrode sheet 102 is provided with a pole ear portion protruding from the diaphragm 110, and the pole ear portion is bent and arranged on the end surface of the winding core to form a pole ear end surface 106 on the end surface of the winding core ... An extension portion 112 is provided at the winding end of 10, and the extension portion 112 is bent and arranged on the pole ear end face 106 to cover at least a portion of the pole ear end face 106, so as to isolate the pole ear portion from the shell 20, thereby realizing the insulation setting of the pole ear portion of the electrode sheet 102; by setting the battery cell 10 in the shell 20 and covering the openings of the shell 20 through the cover assembly to form electrical connection, it is possible to avoid the pole ear portion of the battery cell 10 from contacting with the shell 20 to cause a short circuit.

[0100] In the above embodiment, by providing an extension portion 112 on the diaphragm 110, when the pole piece group 100 and the diaphragm 110 are wound to form a core, the extension portion 112 can be bent toward the core direction of the core, and at least a portion of the extension portion 112 covers the pole ear end face 106, thereby achieving insulation of the pole ear portion, and preventing the pole ear portion of the battery cell 10 from contacting the shell 20 after the battery cell 10 is assembled in the shell 20. There is no need to additionally provide an insulating part for the pole ear portion, which simplifies the pole ear insulation structure of the battery, improves the reliability of the battery, and can improve the manufacturing efficiency of the battery.

[0101] In one embodiment, Figure 6 and Figure 7 As shown, a current collector is provided between the pole lug end face 106 and the protrusion 116 , the current collector is electrically connected to the corresponding pole lug end face 106 , and the protrusion 116 at least partially abuts against the current collector; the cover assembly is electrically connected to the corresponding current collector 40 ; or, the shell 20 is electrically connected to the corresponding current collector 40 .

[0102] Among them, the current collector may be a sheet structure, for example, the current collector may be a current collecting plate. The current collector may be used as an electrical drainage for the electrode, and serves as an electrical connection between the end face 106 of the pole ear and the electrode end. The cover assembly may be electrically connected to the corresponding current collector 40 by welding, and the current collector may be electrically abutted against the cover assembly. For example, a protrusion may be provided on the current collector, and the protrusion of the current collector abuts against the cover assembly, so that the cover assembly has a certain electrical property to prevent the cover assembly from being corroded. In another example, the housing 20 may be electrically connected to the corresponding current collector 40 by welding, so that the current collector 40 is not in contact with the cover assembly.

[0103] For example, the battery cell 10 has a first pole ear end face 1062 and a second pole ear end face 1064, and the current collector includes a first current collector and a second current collector. The first pole ear end face 1062 of the battery cell 10 is electrically connected to the cover plate assembly through the first current collector, so that the cover plate assembly serves as the first output pole of the battery; the second pole ear end face 1064 of the battery cell 10 is welded to the bottom of the shell 20 through the second current collector or directly, so that the shell 20 serves as the second output pole of the battery. For another example, the battery includes a first pole 510, and the first pole 510 is electrically connected to the first pole ear end face 1062 of the battery cell 10 through the first current collector, so that the first pole 510 serves as the first output pole of the battery; the second pole ear end face 1064 of the battery cell 10 is electrically connected to the side wall of the shell 20 or the cover plate assembly through the second current collector, so that the shell 20 or the cover plate assembly serves as the second output stage of the battery. For another example, the battery includes a first electrode 510 and a second electrode 520. The first electrode 510 is electrically connected to the first pole ear end face 1062 of the battery cell 10 through a first current collector, so that the first electrode 510 serves as the first output electrode of the battery; the second electrode 520 is electrically connected to the second pole ear end face 1064 of the battery cell 10 through a second current collector, so that the second electrode 520 serves as the second output electrode of the battery.

[0104] By arranging a current collector between the pole ear end face 106 and the protrusion 116, the current collector is electrically connected to the corresponding pole ear end face 106, and by bending the protrusion 116 and arranging it on the current collector, at least a portion of the protrusion 116 abuts against the current collector. When the battery cell 10 is installed in the shell 20, the pole ear portion of the electrode sheet 102 and the shell 20 can be insulated and isolated by the extension portion 112 of the diaphragm 110, and the current collector and the shell 20 can be insulated and isolated, thereby preventing the pole ear (or current collector) of the battery cell 10 from contacting the shell 20 and causing a short circuit, thereby improving the reliability of the battery.

[0105] In one embodiment, Figure 6 and Figure 7 As shown, the housing 20 is provided with a necked portion 210 adjacent to the opening, and the necked portion 210 is located between the cover assembly and the protrusion 116 .

[0106] The necking portion 210 is recessed into the shell 20, and the necking portion 210 can be used to space the cover plate assembly from the end face of the pole lug 106. The cover plate assembly is arranged above the necking portion 210, for example, the cover plate assembly can be clamped and arranged above the necking portion 210. When the battery cell 10 is arranged in the shell 20, a current collector is arranged on the end face of the pole lug 106, and a protrusion 116 is arranged on the current collector, and a necking portion 210 is arranged on the protrusion 116, so that the end face of the pole lug 106 is insulated and isolated from the cover plate assembly, avoiding contact between the cover plate assembly and the end face of the pole lug 106, and preventing the end face of the pole lug 106 from contacting the shell 20 to cause a battery short circuit, and at the same time facilitating the installation and fixing of the cover plate assembly, thereby improving the assembly efficiency of the battery.

[0107] In one embodiment, the retracted depth of the necked portion 210 is smaller than the protruding length of the protruding portion 116 ; or, the projection of the necked portion 210 on the protruding portion 116 along the axial direction of the winding core is located within the end surface of the protruding portion 116 .

[0108] The protruding length of the protrusion 116 refers to the distance from the end of the protrusion 116 to the inner wall of the shell 20 after the protrusion 116 is bent. The indentation depth of the necking portion 210 is set to L1, and the protruding length of the protrusion 116 is set to L2, then L2>L1 is set, thereby preventing the necking portion 210 from contacting the ear portion of the battery cell 10 and causing a battery short circuit. In another example, in the axial direction of the winding core, the projection of the necking portion 210 on the protrusion 116 is located within the region of the projection of the protrusion 116 in the axial direction, thereby preventing the necking portion 210 from contacting the ear portion of the battery cell 10 and causing a battery short circuit.

[0109] In one example, the protrusion 116 is bent to form a ring structure with a central hole so that the current collector can be exposed and electrically connected to the cover assembly. In addition, the protrusion 116 is bent to cover at least part of the current collector so as to fix the corresponding current collector.

[0110] In one embodiment, Figures 8 to 10 As shown, the battery also includes a first pole 510; a first pole hole is provided at the bottom of the shell 20; one end of the first pole 510 passes through the first pole hole and is electrically connected to the corresponding current collector; and / or, the battery cell 10 also includes a second pole 520; the cover assembly is provided with a second pole hole; one end of the second pole 520 passes through the second pole hole and is electrically connected to the corresponding current collector.

[0111] For example, the first pole hole is used for inserting the first end of the first pole 510, and the first pole hole is also used to limit the first pole 510. The first pole 510 is electrically connected to the corresponding current collector, and the current collector is electrically connected to the corresponding pole ear end face 106, thereby realizing the electrical connection between the first pole 510 and the corresponding pole ear portion of the battery cell 10, so that the first pole 510 serves as the first output pole of the battery. For another example, the second pole hole is used for inserting the first end of the second pole 520, and the second pole hole is also used to limit the second pole 520. The second pole 520 is electrically connected to the corresponding current collector, and the current collector is electrically connected to the corresponding pole ear end face 106, thereby realizing the electrical connection between the second pole 520 and the corresponding pole ear portion of the battery cell 10, so that the second pole 520 serves as the second output pole of the battery.

[0112] In one embodiment, Figure 6 and Figure 8As shown, the cover plate assembly includes a first cover plate 310; a first opening is provided at the top of the shell 20, and the first cover plate 310 covers the first opening; and / or, the cover plate assembly also includes a second cover plate 320; a second opening is provided at the bottom of the shell 20, and the second cover plate 320 covers the second opening.

[0113] The first cover plate 310 is used to cover the first opening of the housing 20. The first cover plate 310 is welded to the housing 20, and the corresponding current collector can be welded to the first cover plate 310, and the corresponding current collector can also be welded to the side wall of the housing 20. In another example, the first cover plate 310 and the housing 20 can also be connected by a snap-on connection, and the first cover plate 310 and the housing 20 can be insulated, and the current collector is welded to the first cover plate 310.

[0114] The second cover plate 320 is used to cover the second opening of the housing 20. The second cover plate 320 and the housing 20 can be welded, and the corresponding current collector 40 can be welded to the second cover plate 320, and the corresponding current collector 40 can also be welded to the side wall of the housing 20. In another example, the second cover plate 320 and the housing 20 can also be connected by a snap-on method, and the second cover plate 320 and the housing 20 can be insulated, and the current collector and the second cover plate 320 are welded.

[0115] In one embodiment, Figure 7 and Fig. 9 As shown, a first insulating member 610 is disposed between the first pole 510 and the housing 20 ; and / or a second insulating member 620 is disposed between the first cover plate 310 and the housing 20 .

[0116] The first insulating member 610 may be disposed in the first opening, and the first insulating member 610 is used to insulate the first pole 510 from the housing 20. The second insulating member 620 is used to insulate the first cover plate 310 from the housing 20.

[0117] By providing a first insulating member 610 in the first pole hole, the first pole 510 is insulated from the housing 20, avoiding contact between the first pole 510 and the housing 20, and preventing the corresponding pole ear end face 106 from contacting the housing 20 and causing a battery short circuit. By providing a second insulating member 620 between the first cover plate 310 and the housing 20, the first cover plate 310 is insulated from the housing 20, avoiding contact between the first cover plate 310 and the housing 20, and preventing the corresponding pole ear end face 106 from contacting the housing 20 and causing a battery short circuit.

[0118] In one embodiment, Fig.10 As shown, a third insulating member 630 is disposed between the second pole 520 and the housing 20 ; and / or a fourth insulating member 640 is disposed between the second cover plate 320 and the housing 20 .

[0119] The third insulating member 630 may be disposed in the second opening, and the third insulating member 630 is used to insulate the third pole from the housing 20. The fourth insulating member 640 is used to insulate the second cover plate 320 from the housing 20.

[0120] By providing a third insulating member 630 in the second pole hole, the second pole 520 is insulated from the housing 20, avoiding contact between the second pole 520 and the housing 20, and preventing the corresponding pole ear end face 106 from contacting the housing 20 and causing a battery short circuit. By providing a fourth insulating member 640 between the second cover plate 320 and the housing 20, the second cover plate 320 is insulated from the housing 20, avoiding contact between the second cover plate 320 and the housing 20, and preventing the corresponding pole ear end face 106 from contacting the housing 20 and causing a battery short circuit.

[0121] In one example, after the protrusion 116 is bent, its projection at the bottom of the shell 20 is connected to or overlaps with the end of the surface portion of the insulating member (the first insulating member 610 or the third insulating member 630) located inside the shell 20, thereby preventing the bottom of the shell 20 from contacting the corresponding pole ear portion of the battery cell 10 and causing a short circuit.

[0122] In one example, if Figure 6 and Figure 7 As shown, the shell 20 has an opening, and the cover assembly is sealed at the opening. The cover assembly includes a first cover 310 and a first insulating member 610. The first electrode tab of the battery cell 10 is electrically connected to the first cover 310 through a first current collector, so that the first cover 310 serves as the first output pole of the battery; the second end of the battery cell 10 is welded to the bottom of the shell 20 through a second current collector or directly, so that the shell 20 serves as the second output pole of the battery, and the protrusion 116 of the extension portion 112 is bent toward the first current collector of the battery cell 10 to prevent the first electrode tab of the battery cell 10 from contacting the shell 20 and causing a battery short circuit.

[0123] In one example, if Figure 8 and Fig. 9 As shown, the shell 20 has an opening, and the cover assembly is used to seal the opening. The bottom of the shell 20 has a first pole hole for the first pole 510 of the battery to pass through. The first pole 510 is electrically connected to the first electrode tab of the battery cell 10 through the first current collector, so that the first pole 510 serves as the first output pole of the battery; the second electrode of the battery cell 10 is electrically connected to the side wall of the shell 20 or the cover assembly through the second current collector, so that the shell 20 or the cover assembly serves as the second output stage of the battery, and a first insulating member 610 is provided between the first pole 510 and the first pole hole to insulate the first pole 510 from the shell 20. The extension portion 112 is provided on the side of the battery cell 10 close to the first electrode tab, and the protrusion 116 of the extension portion 112 is bent toward the first current collector of the battery cell 10 to prevent the first electrode tab of the battery cell 10 from contacting the shell 20 and causing a battery short circuit.

[0124] In one example, the housing 20 has two openings (a first opening and a second opening), and the cover assembly may include a first cover 310 and a second cover 320, the first opening is sealed by the first cover 310, and the second opening is sealed by the second cover 320. The cover assembly also includes a second insulating member 620 and a fourth insulating member 640, the second insulating member 620 is used to insulate the first cover 310 from the housing 20, and the fourth insulating member 640 is used to insulate the second cover 320 from the housing 20; it should be noted that the first insulating member 610 cover assembly may only include the first cover 310 and the second cover 320 (in this case, the first cover 310 is welded at the first opening, and the second cover 320 is welded at the second opening). The first cover plate 310 is provided with a first pole hole, the second cover plate 320 is provided with a second pole hole, and is provided between the first pole hole and the first pole 510 through the first insulating member 610, and the second insulating member 620 is provided between the second pole hole and the second pole 520. The first electrode tab of the battery cell 10 is electrically connected to the first pole 510 through the first current collector, and the second electrode tab is electrically connected to the second pole 520 through the second current collector. The protrusion 116 of the extension 112 is bent toward the first current collector of the battery cell 10, and the protrusion 116 of the other extension 112 is bent toward the second current collector of the battery cell 10, so as to prevent the first electrode tab and the second electrode tab of the battery cell 10 from contacting the housing 20 and causing a short circuit of the battery. It should be noted that when the cover plate assembly includes the first insulating member 610 and the second insulating member 620, the first cover plate 310 can be directly used as the first electrode of the battery, and the second cover plate 320 can be directly used as the second electrode of the battery.

[0125] In one embodiment, Fig.10 As shown, the shell 20 has an opening at one end and a closed end. The cover assembly is used to seal the opening of the shell 20. The bottom of the shell 20 has a first pole hole through which the first pole 510 passes, and the first pole 510 is connected to the first pole hole through the first insulating member 610. The first pole 510 is electrically connected to the first current collector, and the first current collector is electrically connected to the first pole ear end face 1062. The cover plate assembly includes a first cover plate 310 welded to the shell 20, the first cover plate 310 is provided with a second pole hole, the second pole 520 is connected to the second pole hole through the second insulating member 620, the second pole 520 is electrically connected to the second current collector, the second current collector is electrically connected to the second pole ear end face 1064, and extension portions 112 are provided at both ends of the battery cell 10, the protrusion 116 of the extension portion 112 is bent toward the first current collector of the battery cell 10, and the protrusion 116 of the other extension portion 112 is bent toward the second current collector of the battery cell 10, so as to prevent the first electrode ear and the second electrode ear of the battery cell 10 from contacting with the shell 20 and causing a battery short circuit.

[0126] In one embodiment, if Fig.11 As shown, a battery cell manufacturing method is also provided, which is applied to any of the battery cells as described above, and the battery cell manufacturing method comprises the following steps:

[0127] Step S110, providing at least one diaphragm and at least two electrode sheets.

[0128] Each electrode sheet may include a positive electrode sheet and a negative electrode sheet. For the specific description of the separator and the electrode sheet, reference may be made to the specific description of the separator and the electrode sheet in the above embodiment, which will not be repeated here.

[0129] Step S120, cutting the wound end of the diaphragm to form an extension portion.

[0130] The diaphragm has a winding end and a winding start end opposite to each other, the extension part and the diaphragm can be an integrally formed structure, and the extension part is obtained by cutting the winding end of the diaphragm. Exemplarily, the connecting part and the protruding part are obtained by cutting the extension part, the connecting part connects the protruding part and the diaphragm respectively, and the protruding part protrudes from the diaphragm.

[0131] Step S130 , providing the electrode sheet with an electrode ear portion protruding from the diaphragm.

[0132] The pole ear and the electrode sheet may be an integrally formed structure, and the electrode sheet is provided with an uncoated area protruding from the diaphragm. The pole ear is obtained by coating the electrode sheet with active material and cutting the area not coated with active material.

[0133] In step S140 , the cut separator is stacked between two adjacent electrode sheets, and the stacked electrode sheets and separator are wound to form a winding core.

[0134] The electrode sheets and the separators are stacked, and the separators and the electrode sheets are wound to form a winding core based on the winding starting ends of the electrode sheets and the separators, and the extended portions of the separators are further wound so that the extended portions cover the outside of the electrode sheets.

[0135] Step S150, bending the pole ear portion and setting it on the end surface of the winding core to form a pole ear end surface on the end surface of the winding core.

[0136] For example, the first pole ear portion is bent and arranged on the corresponding end face of the winding core, thereby forming the first pole ear end face on the corresponding end face of the winding core; the second pole ear portion is bent and arranged on the corresponding end face of the winding core, thereby forming the second pole ear end face on the corresponding end face of the winding core.

[0137] Step S160, bending the extension portion and disposing it on the end surface of the pole lug to cover at least a portion of the end surface of the pole lug, so as to isolate the pole lug portion from the shell.

[0138] The extension portion is bent and arranged on the end face of the pole ear and covers at least a portion of the end face of the pole ear. When the battery cell is installed in the shell, the extension portion of the diaphragm can insulate and isolate the pole ear of the electrode sheet from the shell to prevent the pole ear of the battery cell from contacting the shell and causing a short circuit.

[0139] In the above-mentioned embodiment, by providing an extension portion on the diaphragm, when the pole piece group and the diaphragm are wound to form a core, the extension portion can be bent toward the core direction of the core, and at least part of the extension portion covers the end face of the pole ear, thereby achieving insulation of the pole ear portion and preventing the pole ear portion from contacting the shell. There is no need to additionally provide an insulating part for the pole ear portion, which simplifies the pole ear insulation structure of the battery cell, improves the reliability of the battery cell, and can improve the manufacturing efficiency of the battery.

[0140] In one embodiment, the step of providing the electrode sheet with a lug portion protruding from the diaphragm comprises:

[0141] The electrode sheet is divided into a coated area and an uncoated area, wherein the uncoated area protrudes from the diaphragm; the coated area is coated with an active material to form an active material layer; and the uncoated area is cut to form an electrode ear.

[0142] For example, the positive electrode plate includes a first coated area coated with an active material layer along the winding direction and a first uncoated area that is not coated with the active material layer and exposed outside the diaphragm. The first uncoated area is cut to form the ear portion of the positive electrode plate, and the first uncoated area is bent along the radial direction of the battery cell to form a first ear end face.

[0143] For another example, the negative electrode plate includes a second coated area coated with an active material layer along the winding direction and a second uncoated area that is not coated with the active material layer and exposed outside the diaphragm. The second uncoated portion is cut to form the ear portion of the negative electrode plate, and the second uncoated area is bent along the radial direction of the battery cell to form a second ear end face.

[0144] In one embodiment, the step of bending the extension portion and arranging it on the end face of the pole lug to cover at least a portion of the end face of the pole lug so as to isolate the pole lug portion from the housing comprises:

[0145] A current collecting member is arranged on the end surface of the pole lug to electrically connect the end surface of the pole lug to the current collecting member; the extension portion is bent and arranged on the current collecting member to cover at least a portion of the current collecting member.

[0146] When the protruding portion of the extension portion is bent, it can be bent together with the pole lug portion, so that the pole lug portion forms a pole lug end face, and the protruding portion covers at least a portion of the pole lug end face.

[0147] Exemplarily, when winding, first wind to the position of the extension portion, then bend the pole ear portion to form the pole ear end face, and then weld the current collector to the pole ear end face; then continue to wind the extension portion, and bend the protrusion of the extension portion toward the pole ear end face, so that the protrusion covers at least part of the current collector, thereby preventing the pole ear end face from contacting the shell and causing a short circuit, thereby improving the reliability of the battery and being able to improve the manufacturing efficiency of the battery.

[0148] It should be noted that when bending the protruding portion, cuts may be provided on the protruding portion at a preset interval, thereby obtaining a plurality of protruding sub-portions, which facilitates the bending of the protruding sub-portions.

[0149] It should be understood that although Fig.11 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Fig.11 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0150] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0151] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A battery cell, characterized in that: include: An electrode group, the electrode group comprising at least two electrode sheets, each of which is stacked; A separator, wherein the separator is stacked between two adjacent electrode sheets; the separator and the electrode sheets are wound to form a winding core; The electrode sheet is provided with a pole ear portion protruding from the diaphragm, and the pole ear portion is bent and arranged on the end face of the winding core to form a pole ear end face on the end face of the winding core; the winding end of the diaphragm is provided with an extension portion, and the extension portion is bent and arranged on the pole ear end face to cover at least part of the pole ear end face to isolate the pole ear portion from the shell.

2. The battery cell according to claim 1, characterized in that: The extension portion includes a connecting portion and a protruding portion; The connecting portion is connected to the winding end of the diaphragm, the protruding portion is connected to the connecting portion, the protruding portion protrudes from the corresponding pole lug end surface along the axial direction of the winding core, and the protruding portion is bent and arranged on the pole lug end surface.

3. The battery cell according to claim 2, characterized in that: The protrusion includes at least two protrusion sub-parts; and a gap is provided between two adjacent protrusion sub-parts.

4. The battery cell according to claim 3, characterized in that: The length of the slit is less than or equal to the protruding length of the corresponding protruding sub-portion.

5. The battery cell according to claim 2, characterized in that: The length of the connecting portion along the winding direction is less than or equal to the length of the diaphragm along the winding direction; The length of the protrusion along the winding direction is less than or equal to the length of the diaphragm along the winding direction.

6. The battery cell according to claim 3, characterized in that: The length of the extension portion is greater than or equal to the length of one circle of the winding core starting from the winding end of the winding core.

7. The battery cell according to claim 6, characterized in that: The length of the extension portion is greater than or equal to the length of two turns of the winding core starting from the winding end of the winding core.

8. The battery cell according to claim 1, characterized in that: The extension portion is provided with at least one first through hole; the first through hole is used to pass the electrical connector so as to connect the pole ear portion with the electrical connector.

9. The battery cell according to claim 1, characterized in that: A winding start end of the separator protrudes beyond a winding start end of the adjacent electrode sheet.

10. The battery cell according to claim 9, characterized in that: The length of the winding start end of the separator protruding from the winding start end of the adjacent electrode sheet is greater than twice the circumference of the winding needle.

11. The battery cell according to any one of claims 1 to 10, characterized in that: The electrode sheet group includes adjacent first electrode sheets and second electrode sheets; The first electrode sheet is provided with a first pole ear portion protruding from the diaphragm, and the first pole ear portion is bent and arranged on the first end surface of the winding core to form a first pole ear end surface on the end surface of the winding core; the second electrode sheet is provided with a second pole ear portion protruding from the diaphragm, and the second pole ear portion is bent and arranged on the second end surface of the winding core to form a second pole ear end surface on the end surface of the winding core; A first extension portion is disposed at the winding end of the diaphragm, and the first extension portion is bent and disposed on the end surface of the first pole lug to cover at least a portion of the end surface of the first pole lug; And / or, a second extension portion is provided at the winding end of the separator, and the second extension portion is bent and arranged on the second pole lug end surface to cover at least a portion of the second pole lug end surface.

12. A battery, characterized in that: Comprising a shell, a cover assembly and a battery cell as claimed in any one of claims 2 to 11; The shell is provided with at least one opening, the battery cell is arranged in the shell, and the cover assembly is used for covering each of the openings.

13. The battery according to claim 12, characterized in that A current collecting piece is arranged between the end face of the pole lug and the protrusion, the current collecting piece is electrically connected to the corresponding end face of the pole lug, and the protrusion at least partially abuts against the current collecting piece; The cover assembly is electrically connected to the corresponding current collector; or the shell is electrically connected to the corresponding current collector.

14. The battery according to claim 12, characterized in that The shell is provided with a necked portion adjacent to the opening, and the necked portion is located between the cover assembly and the protruding portion.

15. The battery according to claim 14, characterized in that The retracted depth of the constricted portion is less than the protruding length of the protruding portion; Alternatively, a projection of the necked portion on the protruding portion along the axial direction of the winding core is located within an end surface of the protruding portion.

16. The battery according to claim 13, characterized in that It also includes a first pole; a first pole hole is provided at the bottom of the shell; one end of the first pole passes through the first pole hole and is electrically connected to the corresponding current collector; And / or, the battery cell further includes a second pole; the cover assembly is provided with a second pole hole; one end of the second pole passes through the second pole hole and is electrically connected to the corresponding current collecting member.

17. The battery according to claim 16, characterized in that The cover plate assembly comprises a first cover plate; a first opening is provided on the top of the housing, and the first cover plate covers the first opening; And / or, the cover plate assembly further includes a second cover plate; a second opening is provided at the bottom of the shell, and the second cover plate covers the second opening.

18. The battery according to claim 17, characterized in that A first insulating member is provided between the first pole and the shell; and / or a second insulating member is provided between the first cover plate and the shell.

19. The battery according to claim 17, characterized in that A third insulating member is provided between the second pole and the shell; and / or a fourth insulating member is provided between the second cover plate and the shell.

20. A method for manufacturing a battery cell, characterized in that: Applied to the battery cell according to any one of claims 1 to 11, the battery cell manufacturing method comprises the following steps: Providing at least one diaphragm and at least two electrode sheets; cutting the wound end of the diaphragm to form an extension portion; The electrode sheet is provided with a pole ear portion protruding from the diaphragm; The cut separator is stacked between two adjacent electrode sheets, and the stacked electrode sheets and the separator are wound to form a winding core; The pole ear portion is bent and arranged on the end surface of the winding core to form a pole ear end surface on the end surface of the winding core; The extension portion is bent and disposed on the end surface of the pole lug to cover at least a portion of the end surface of the pole lug, so as to isolate the pole lug portion from the shell.

21. The method for manufacturing a battery cell according to claim 20, characterized in that: The step of providing the electrode sheet with a lug portion protruding from the diaphragm comprises: Dividing the electrode sheet into a coated area and an uncoated area, wherein the uncoated area protrudes from the diaphragm; The coated area is coated with active material to form an active material layer; and the uncoated area is cut to form the electrode lug portion.

22. The method for manufacturing a battery cell according to claim 20 or 21, characterized in that: The step of bending the extension portion and arranging it on the end face of the pole lug to cover at least a portion of the end face of the pole lug so as to isolate the pole lug portion from the housing comprises: A current collector is arranged on the end surface of the pole lug to electrically connect the end surface of the pole lug with the current collector; The extension portion is bent and disposed on the current collecting member to cover at least a portion of the current collecting member.

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