CN219534818U - Battery cell and battery - Google Patents

Abstract

The utility model relates to a battery cell and a battery, wherein the battery cell comprises N first electrode plates and M second electrode plates opposite to the first electrode plates in electrical property, and the first electrode plates and the second electrode plates are alternately laminated; n is more than or equal to 2, M is more than or equal to 1; the first electrode plate comprises a first electrode plate body, a first current collector extension part connected with a first current collector in the first electrode plate body and a first electrode lug; the first current collector extension part and the first tab are stacked; the first electrode plate is provided with a first welding mark for connecting the first current collector extension part and the first tab; the second electrode plate comprises a second plate body, a second current collector extension part connected with a second current collector in the second plate body and a second lug; the first conductive piece is arranged between at least two adjacent first current collector extending parts, so that the contact internal resistance between the first current collector extending parts and the first electrode lugs can be reduced, and the conductive performance of the battery is improved.

Description

Battery cell and battery

The present utility model claims priority from the chinese patent office, application number 202223314298.2, chinese patent application entitled "cell and battery", filed on day 12 and 06 of 2022, the entire contents of which are incorporated herein by reference.

Technical Field

The utility model belongs to the technical field of batteries, and particularly relates to a battery cell and a battery.

Background

In order to improve the nailing performance of the battery cell, the current collector is generally converted into a composite current collector from a metal foil (such as copper foil and aluminum foil), wherein the composite current collector comprises an insulating layer and metal layers positioned on the upper side and the lower side of the insulating layer. The existence of insulating layer has increased the welding degree of difficulty of utmost point ear and compound current collector, simultaneously because the existence of middle insulating layer, the welding is difficult to realize switching on of upper and lower both sides metal level, and then can't accomplish the effective output of electron.

Disclosure of Invention

The utility model provides a battery core, which utilizes a first conductive piece to realize electric conduction between adjacent first current collector extension parts, and utilizes first welding marks to realize electric conduction between the first current collector extension parts and first electrode lugs, so that the contact internal resistance between the first current collector extension parts and the first electrode lugs can be reduced under the combined action of the first conductive piece and the first welding marks, and the electric conduction performance of a battery is improved.

The utility model also provides a battery which has excellent electric conduction performance due to the battery core.

The battery cell provided by the utility model comprises N first electrode plates, M second electrode plates and first electrode lugs, wherein the M second electrode plates are opposite to the first electrode plates in electrical property, and the first electrode plates and the second electrode plates are alternately laminated; n is more than or equal to 2, M is more than or equal to 1;

The first electrode plate comprises a first electrode plate body and a first current collector extension part connected with a first current collector in the first electrode plate body; the first current collector extension part and the first tab are stacked; the first pole piece is provided with a first welding mark for connecting the first current collector extension part and the first pole lug;

the second electrode plate comprises a second plate body and a second current collector extension part connected with a second current collector in the second plate body;

wherein a first conductive member is disposed between at least two adjacent first current collector extensions.

In the battery cell, at least one side of the battery cell is provided with a metal protection layer in the stacking direction;

the metal protection layer includes a metal protection layer extension;

the polarity of the metal protection layer is the same as that of the first electrode plate, and the metal protection layer extension part and the first current collector extension part are correspondingly arranged;

the metal protection layer extension is connected with the first current collector extension through the first welding mark.

The battery cell, wherein the first tab is laminated on the surface of the extending part of the metal protection layer, which is far away from the center of the battery cell;

The surface of the first tab, which is far away from the extending part of the metal protection layer, is also provided with a first bulge, and the first bulge is connected with the first welding mark.

The battery cell further comprises a second lug, M is more than or equal to 2, and the second current collector extension part and the second lug are arranged in a stacked mode; the second electrode sheet is provided with a second welding mark for connecting the second current collector extension part and a second lug;

a second conductive member is disposed between at least two adjacent second current collector extensions.

In the battery cell, at least one side of the battery cell is provided with a metal protection layer in the stacking direction;

the polarity of the metal protection layer is the same as that of the second electrode plate, and the metal protection layer extension part and the second current collector extension part are correspondingly arranged;

the metal protection layer extension is connected with the second current collector extension through the second welding mark.

The battery cell is characterized in that the second electrode lug is arranged on the surface of the extending part of the metal protection layer, which is far away from the center of the battery cell;

the surface of the second lug far away from the extending part of the metal protection layer is also provided with a second bulge, and the second bulge is connected with the second welding mark.

A third conductive member is disposed between the metal protection layer extension and the adjacent first current collector extension, or

A third conductive element is disposed between the metal protection layer extension and the adjacent second current collector extension.

As described above, the side of the first tab away from the center of the battery core is provided with the first insulating adhesive layer covering the first solder mark, and the first insulating adhesive layer is connected with the extending part of the metal protection layer; and/or the number of the groups of groups,

and one side of the second lug far away from the center of the battery cell is provided with a second insulating adhesive layer covering the second welding mark, and the second insulating adhesive layer is connected with the extending part of the metal protection layer.

The battery cell, wherein the first welding mark is a welding mark of laser welding;

the second welding mark is an ultrasonic welding mark.

The battery cell, wherein the thickness of the first bulge is 0-0.1 mm; and/or the number of the groups of groups,

the thickness of the second bulge is 0-0.1 mm; and/or the number of the groups of groups,

the thickness of the first welding mark is 0.01-30 mm; and/or the number of the groups of groups,

the thickness of the second welding mark is 0.01-30 mm; and/or the number of the groups of groups,

the tensile force between the first tab and the first current collector extension part is not less than 2N, and the foil sticking area is 30% -100%; and/or the number of the groups of groups,

The tensile force between the second lug and the second current collector extension part is not less than 2N, and the sticky foil area is 30% -100%.

A cell as described above, wherein the relative difference in thickness of the first protrusion and the second protrusion is no greater than 40%; and/or the number of the groups of groups,

the relative difference between the thicknesses of the first welding mark and the second welding mark is not more than 50%; and/or the number of the groups of groups,

the relative difference between the pull force between the first tab and the first current collector extension and the pull force between the second tab and the second current collector extension is no greater than 30%; and/or the number of the groups of groups,

the relative difference in the sticky foil area between the first tab and the first current collector extension and the sticky foil area between the second tab and the second current collector extension is no greater than 30%.

The battery cell comprises the first current collector, wherein the first current collector is a first composite current collector, and the first composite current collector comprises a first polymer layer and first metal layers positioned on two surfaces of the first polymer layer; and/or the number of the groups of groups,

the second current collector is a second composite current collector, and the second composite current collector comprises a second polymer layer and second metal layers positioned on two surfaces of the second polymer layer.

A cell as described above, wherein,

The thickness of the metal protection layer is more than or equal to that of the first electrode slice, or

The thickness of the metal protection layer is larger than or equal to that of the second electrode plate.

The battery cell as described above, wherein the metal protection layer is provided with an active layer on a side of the first current collector extension.

The battery cell, wherein a diaphragm is arranged on one side of the metal protection layer, which is close to the center of the battery cell; the end of the diaphragm is bonded to the end of the metal protection layer.

The battery cell comprises a first electrode plate and a second electrode plate which are adjacent to each other, wherein a diaphragm is arranged between the first electrode plate and the second electrode plate

The battery cell as described above, wherein the membrane comprises adjacent first and second membranes, at least one first and at least one second membrane being connected to the first electrode pad or the second electrode pad.

In the battery cell, the boundary of the diaphragm connecting part is positioned outside the boundary of the first electrode slice or the second electrode slice,

the projection of the first conductive piece is not overlapped with the projection of the diaphragm connecting portion, and the projection of the second conductive piece is not overlapped with the projection of the diaphragm connecting portion.

The battery provided by the utility model comprises the battery core.

The implementation of the utility model has at least the following beneficial effects:

according to the battery core provided by the utility model, the first conductive piece is used for conducting electricity between the adjacent first current collector extending parts, meanwhile, the first welding printing is used for conducting electricity between the first current collector extending parts and the first electrode lugs, and the contact internal resistance between the first current collector extending parts and the first electrode lugs can be reduced under the combined action of the first conductive piece and the first welding printing, so that the conductivity of the battery is improved.

The utility model also provides a battery which has excellent electric conduction performance due to the battery core.

Drawings

In order to more clearly illustrate the technical solutions of the present utility model, the drawings that are needed in the description of the embodiments of the present utility model will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram illustrating the installation of a battery cell according to an embodiment of the present utility model;

fig. 2 is a schematic view illustrating the installation of the first collector extension and the first tab in the cell of fig. 1;

FIG. 3 is a schematic view of the second current collector extension, metal protection layer and second tab of the cell of FIG. 1;

fig. 4 is a schematic structural view of a first electrode tab in the cell of fig. 1;

fig. 5 is a schematic structural view of a second electrode tab in the cell of fig. 1;

FIG. 6 is a schematic diagram showing the installation of a battery cell according to another embodiment of the present utility model;

fig. 7 is a schematic view illustrating the installation of the first current collector extension, the metal protection layer and the first tab in the battery cell of fig. 6;

FIG. 8 is a schematic top view of an electrode sheet according to an embodiment of the present utility model;

fig. 9 is a schematic top view of a battery according to an embodiment of the present utility model.

Reference numerals illustrate:

1-a first electrode sheet; 10-a first pole piece body;

101-a first current collector; 102-a first current collector extension; 103-a first active material layer; 104-a ceramic layer; 105-a first tab; 106-first welding and printing; 107-first protrusions;

1011-a first polymer layer; 1012-a first metal layer;

2-a second electrode sheet; 20-a second pole piece body;

201-a second current collector; 202-a second current collector extension; 203-a second active material layer; 205-second pole ear; 206-second welding; 207-second bump;

2011-a second polymer layer; 2012-a second metal layer;

301-a first conductive member; 302-a second conductive member; 303-a third conductive member;

401-a metal protective layer; 4011-active moiety; 4012-metal cap extension; 402-an active layer;

a 5-separator; 501-a first separator; 502-a second separator; 503-a septum connection;

6-a first notch; 61-arc line segment;

701-a first insulating adhesive layer; 702-a second insulating glue layer;

8-an electric core; 9-a shell.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments of the present utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In fig. 1 to 8, X is the width direction of the cell, Y is the length direction of the cell, and Z is the stacking direction of the cells and also the thickness direction.

The electrode slice provided by the utility model comprises N first electrode slices 1, M second electrode slices 2 and first electrode lugs 105, wherein the electrical properties of the M second electrode slices 2 are opposite to those of the first electrode slices, and the first electrode slices 1 and the second electrode slices 2 are alternately laminated; n is more than or equal to 2, M is more than or equal to 1; the first electrode tab 1 includes a first tab body 10, a first current collector extension 102 connected to a first current collector 101 in the first tab body 10; wherein the first current collector extension 102 is stacked with the first tab 105; the first electrode sheet 1 is provided with a first weld 106 connecting the first current collector extension 102 and the first tab 105; the second electrode tab 2 includes a second tab body 20, a second current collector extension 202 connected to a second current collector 201 in the second tab body 20; wherein a first conductive member 301 is disposed between at least two adjacent first current collector extensions 102.

In the utility model, the electrode plate is divided into a first electrode plate 1 and a second electrode plate 2 according to different electrode plate electrical properties. The first electrode sheet 1 and the second electrode sheet 2 are positive electrode sheets or negative electrode sheets, so long as the polarity of the first electrode sheet 1 and the polarity of the second electrode sheet 2 are opposite. For example, when the first electrode sheet 1 is a positive electrode sheet, the second electrode sheet 2 is a negative electrode sheet; when the first electrode sheet 1 is a negative electrode sheet, the second electrode sheet 2 is a positive electrode sheet.

In the battery cell, each first electrode tab 1 and each second electrode tab 2 are alternately stacked.

The first electrode tab 1 includes a first tab body 10 and a first current collector extension 102 connected to a first current collector 101 in the first tab body.

Wherein the first pole piece body 10 comprises a first current collector 101 and a first active material layer 103.

The present utility model is not limited to the positional relationship of the first current collector extension 102 and the first current collector 101, and for example, the first current collector extension 102 may be disposed in the length direction or the width direction. As shown in fig. 8, the first current collector 101 has two ends in the longitudinal direction, and the first current collector extension 102 is formed by extending away from the first active material layer 103 from at least a part of the end surface of one end, and the surface of the first current collector extension 102 is not provided with the first active material layer 103. At this time, the size of the first current collector extension 102 in the width direction does not exceed the size of the first current collector 101.

The second electrode tab 2 includes a second tab body 20, a second current collector extension 202 connected to a second current collector 201 in the second tab body 20, and a first tab.

Wherein the second tab body 20 includes a second current collector 201 and a second active material layer 203. The present utility model is not limited to the positional relationship of the second current collector extension 202 and the second current collector 201, and for example, the second current collector extension 202 may be disposed in the length direction or the width direction. Illustratively, the second current collector 201 has two ends in the length direction, the second current collector extension 202 is formed by extending away from the second active material layer 203 from at least a part of the end surface of one end, and the surface of the second current collector extension 202 is not provided with the second active material layer 203. At this time, the size of the second current collector extension 202 in the width direction does not exceed the size of the second current collector 201.

The specific choices of the first electrode sheet 1 and the second electrode sheet 2 are not limited in the present utility model. When one of the first electrode plate 1 and the second electrode plate 2 is an anode plate, the current collector corresponding to the anode plate is aluminum foil, an aluminum-plated film composite current collector and the like, the material of the active substance layer is ternary material or anode active material such as lithium iron phosphate and the like, and the electrode lug is aluminum foil. When one of the first electrode sheet 1 and the second electrode sheet 2 is a negative electrode sheet, the current collector corresponding to the negative electrode sheet is copper foil, nickel-plated copper foil or copper-plated film composite current collector, nickel-plated film composite current collector or the like, the material of the active material layer is a negative electrode active material such as graphite, graphene, lithium titanate, silicon carbon or the like, and the tab is nickel foil or copper nickel plating.

When the battery cell is formed by stacking the components including the N first electrode pieces 1 and the M second electrode pieces 2, the first electrode pieces 1 and the second electrode pieces 2 are alternately stacked, and it can be understood that a separator is further provided between the first electrode pieces 1 and the second electrode pieces 2 to prevent the first electrode pieces 1 and the second electrode pieces 2 from contacting in order to avoid a short circuit. Further, in the process of alternately stacking the first and second tab bodies 10 and 20 correspond to each other in the stacking direction (i.e., the projections of each of the first and second tab bodies 10 and 20 on either separator film are maximally overlapped) to achieve deintercalation of active ions, while the first and second current collector extensions 102 and 202 do not correspond to each other in the stacking direction (i.e., the projections of the first and second current collector extensions 102 and 202 on a common plane are independent of each other, without any overlapping or covering relationship, under the incident light parallel to the stacking direction). However, each first current collector extension 102 corresponds to each other in the stacking direction (i.e., the projection of each first current collector extension 102 onto any one of the separators maximizes the overlap under the incident light parallel to the stacking direction), and each second current collector extension 202 corresponds to each other in the stacking direction (i.e., the projection of each second current collector extension 202 onto any one of the separators maximizes the overlap under the incident light parallel to the stacking direction).

It should be noted that the extending directions of the first current collector extension 102 and the second current collector extension 202 may be the same or different, so long as each first current collector extension 102 corresponds to each other in the stacking direction, and each second current collector extension 202 corresponds to each other in the stacking direction.

In the cell of the present utility model, the first conductive material 301 is provided between at least two first current collector extensions 102 among the adjacent N first extensions, and at this time, the first conductive material 301 and the first current collector extensions 102 are alternately laminated in a direction that matches the lamination direction of the first electrode tab 1 and the second electrode tab 2. It should be noted that, adjacent here means that there is no other first current collector extension 102 between two first current collector extensions 102.

In the utility model, the first electrode plate is provided with a first welding mark for connecting the first current collector extension part and the first tab. At this time, both surfaces of the first conductive member are connected with the adjacent first current collector extension.

At this time, the first conductive member 301 electrically conducts between the adjacent first current collector extensions 102. When the first current collector extension 102 is used to connect the first tab, the contact internal resistance between the first current collector extension 102 and the first tab can be reduced, thereby improving the conductivity of the battery.

In order to further enhance the electrical conduction of the adjacent first current collector extension portions 102, each two adjacent first current collector extension portions 102 are provided with the first conductive member 301, so that the electrical conduction of each two adjacent first current collector extension portions 102 is achieved, and therefore, only one first current collector extension portion 102 of the N first electrode plates 1 needs to be led out to be connected with the first tab.

The specific choice of the first conductive member 301 is not limited in the present utility model, and may be determined according to the specific choice of the first electrode sheet. For example, when the first electrode sheet 1 is the positive electrode, the materials of the first conductive member 301 and the first current collector 101 are the same, for example, when the first current collector 101 is an aluminum foil, the first conductive member 301 is an aluminum foil; when the first current collector 101 is a copper foil, a nickel plated copper foil, the first conductive member 301 is a copper foil, a nickel foil, or the like.

The present utility model is not limited to the number of first conductive members 301 between each two adjacent first current collector extensions 102, for example, at least one, and as the number increases, the conductivity increases.

The manner in which the first tabs 105 and the first current collector extensions 102 are stacked is not limited in the present utility model, as long as each first current collector extension 102 and the first tab 105 correspond to each other in the stacking direction (i.e., the projection of each first current collector extension 102 and the first tab on any separator is maximally overlapped under the incident light parallel to the stacking direction).

The first electrode sheet is provided with a first solder 106, and the first solder 106 connects each of the first current collector extensions 102 and the first tab 105 in the lamination direction. The first tab 105 is electrically connected to each of the first current collector extensions 102 by the first solder 106.

The first solder 106 penetrates the first tab 105 and penetrates part or all of the first current collector extension 102, as long as the connection between the first tab 105 and the first current collector extension 102 is possible.

The present utility model does not limit the structural composition and number of the first solder marks 106, as long as the first tab 105 connected to the first solder marks 106 and the first current collector extension 102 can be electrically connected.

Further, when the first conductive member 301 is disposed between the adjacent first current collector extensions 102, the first solder marks 106 can also connect the first conductive member 301, and under the combined action of the first conductive member 301 and the first solder marks 106, electrical conduction between the adjacent first current collector extensions 102 and electrical conduction between the first tab 105 and each first current collector extension 102 are simultaneously achieved, so that the contact internal resistance between the first current collector extension 102 and the first tab 105 can be reduced, thereby improving the electrical conductivity of the battery.

In order to further improve the electrical conduction strength between the first tab 105 and the first current collector extension 102, in one embodiment of the present utility model, the first tab 105 is stacked on the surface of the first or nth first current collector extension 102; the surface of the first tab 105 remote from the first current collector extension 102 is further provided with a first protrusion 107, and the first protrusion 107 is connected to the first solder 106.

In the above embodiment, the first and nth first current collector extensions 102 and 102 are calculated in terms of the lamination direction, and it is understood that the first and nth first current collector extensions 102 and 102 (also referred to as outermost first current collector extensions) are located away from the center of the cell with respect to the other first current collector extensions 102. At this time, the first tab 105 is located on the surface of the outermost first current collector extension 102 away from the center of the cell.

The surface of the first tab 105 far away from the first current collector extension 102 is further provided with a first protrusion 107, and the first protrusion 107 serves as a limiting member to fix the first tab 105 on the first current collector extension 102 at the outermost side so as to avoid the first tab 105 from falling off. At the same time, the first bump 107 is connected to the first solder 106, which can further enhance the electrical conduction between the first tab 105 and the first current collector extension 102.

Further, when M is greater than or equal to 2, in order to further enhance the electrical conductivity of the cell, a second conductive member 302 is disposed between at least two adjacent second current collector extensions 202. At this time, the second conductive members 302 and the second current collector extension 202 are alternately stacked in a direction coincident with the stacking direction of the first electrode tab 1 and the second electrode tab 2. It should be noted that adjacent here means that there is no other second current collector extension 202 therebetween.

In the present utility model, the second electrode sheet 2 is provided with a second solder mark connecting the second current collector extension and the second tab, and at this time, both surfaces of the second conductive member are connected with the adjacent second current collector extension.

At this time, the second conductive member 302 enables electrical conduction between the adjacent second current collector extensions 202, and when the second current collector extensions 202 are used to connect the tabs, the internal contact resistance between the second current collector extensions 202 and the tabs can be reduced, thereby improving the conductivity of the battery.

In order to further enhance the electrical conduction of the adjacent second current collector extension parts 202, the second conductive members 302 are disposed in each two adjacent second current collector extension parts 202, so that the electrical conduction of each two adjacent second current collector extension parts 202 is achieved, and only one second current collector extension part 202 of the M second electrode plates 2 needs to be led out to be connected with the second electrode lug.

The specific choice of the second conductive member 302 is not limited in the present utility model, and may be determined according to the specific choice of the second electrode sheet 2. For example, when the second electrode sheet 2 is the positive electrode, the second conductive member 302 and the second current collector 201 are selected identically, for example, when the second current collector 201 is an aluminum foil, the second conductive member 302 is an aluminum foil; when the second current collector 201 is a copper foil, a nickel plated copper foil, the second conductive member 302 is a copper foil, a nickel foil, or the like.

The present utility model is not limited to the number of second conductive members 302 between each two adjacent second current collector extensions 202, for example, at least one, and as the number increases, the conductivity increases.

In the above embodiment, when M is equal to or greater than 2, the second current collector extension is stacked with the second tab; the second current collector extension 202 is provided with a second solder 206, and the second electrode tab is provided with a second solder 206 connecting the second current collector extension 202 and the second tab.

The manner in which the second tabs 205 and the second current collector extensions 202 are stacked is not limited in the present utility model, as long as each of the second current collector extensions 202 and the second tabs correspond to each other in the stacking direction (i.e., the projection of each of the second current collector extensions 202 and the second tabs on any separator is maximally overlapped under the incident light parallel to the stacking direction).

A second solder 206 is provided on the second electrode sheet 2, and the second solder 206 connects each second current collector extension 202 and the second tab 205 in the lamination direction. The second tab 205 is electrically conductive with each second current collector extension 202 using the second solder 206.

The structural composition of the second solder 206 is not limited in the present utility model, as long as the second tab 205 connected to the second solder 206 and the second current collector extension 202 can be electrically connected.

Further, when the second conductive member 302 is disposed between the adjacent second current collector extensions 202, the second solder marks 206 can also connect the second conductive member 302, and under the combined action of the second conductive member 302 and the second solder marks 206, the electrical conduction between the adjacent second current collector extensions 202 and the electrical conduction between the second tab 205 and each second current collector extension 202 are simultaneously achieved, so that the contact internal resistance between the second current collector extension 202 and the second tab 205 can be reduced, thereby improving the electrical conductivity of the battery.

In order to further enhance the electrical conductivity between the second tab 205 and the second current collector extension 202, in one embodiment of the present utility model, the second tab 205 is stacked on the surface of the first or the M-th second current collector extension 202; the surface of the second tab 205 remote from the second current collector extension 202 is also provided with a second protrusion 207, the second protrusion 207 being connected to a second solder 206.

In the above embodiment, the first and M-th second current collector extensions 202 and 202 are calculated in terms of the lamination direction, and it is understood that the first and M-th second current collector extensions 202 and 202 (also referred to as outermost second current collector extensions) are located away from the center of the battery cell with respect to the other second current collector extensions 202. At this time, the second tab 205 is located on the surface of the outermost second current collector extension 202 that is remote from the center of the cell.

The surface of the second tab 205 remote from the second current collector extension 202 is further provided with a second protrusion 207, and the second protrusion 207 serves as a limiting member to fix the second tab 205 on the outermost second current collector extension 202 so as to avoid the second tab 205 from falling off. At the same time, the second bump 207 is connected to the second solder 206, which can further enhance the electrical conduction between the second tab 205 and the second current collector extension 202.

The specific dimensions of the first solder 106, the second solder 206, the first bump 107 and the second bump 207 are not limited, and may be adjusted according to practical situations. In order to ensure flatness of the lamination area of the tab (first tab or second tab) and the current collector extension (first current collector extension 102 or second current collector extension 202), in one embodiment, the thickness of the first protrusion 107 is 0 to 0.1mm; the thickness of the second protrusion 207 is 0 to 0.1mm; the thickness of the first welding mark 106 is 0.01 mm-30 mm; the thickness of the second solder mark 206 is 0.01mm to 30mm.

In the utility model, the combined action of the first welding mark 106 and the first protrusion 107 realizes the fixed connection and electric conduction between the tab (the first tab or the second tab) and the current collector extension part (the first current collector extension part 102 or the second current collector extension part 202). The utility model does not limit the tension force and the foil sticking area between the tab and the current collector extension part, and can be adjusted and determined according to actual conditions, in one embodiment, the tension force between the first tab 105 and the first current collector extension part 102 is not less than 2N, and the foil sticking area is 30% -100%; the tensile force between the second tab 205 and the second current collector extension 202 is not less than 2N, and the sticky foil area is 30% -100%. The pulling force refers to the magnitude of the corresponding force when the tab is pulled at an angle of 180 degrees in the battery cell and torn; the foil sticking area refers to the area of the tab remaining on the surface of the current collector extension after the tab is stretched/the percentage of the lamination area of the tab and the current collector extension.

In one embodiment, the relative difference in thickness of the first protrusion 107 and the second protrusion 207 is no greater than 40%; and/or the relative difference in thickness of the first solder 106 and the second solder 206 is no greater than 50%; and/or, a relative difference in tension between the first tab 105 and the first current collector extension 102 and the second tab 205 and the second current collector extension 202 is no greater than 30%; and/or, the relative difference between the adhesive foil area between the first tab 105 and the first current collector extension 102 and the adhesive foil area between the second tab 205 and the second current collector extension 202 is not greater than 30%, so that the consistency of the first electrode plate and the second electrode plate can be ensured, the gap between the battery cell and a battery shell (such as an aluminum plastic film) in the process of assembling the battery is reduced, and the energy density of the battery cell is improved.

In one embodiment, as shown in fig. 9, a first insulating adhesive layer 701 covering the first solder is disposed on a side of the first tab 105 away from the center of the battery cell; and/or, one side of the second lug 205 far from the center of the battery cell is provided with a second insulating adhesive layer 702 covering the second welding mark 7. The insulating adhesive layer can prevent the protrusions on the surface of the electrode lug from being contacted with the electrode plates with opposite polarities, so that short circuit is avoided.

The present utility model is not limited to a particular type of selection of current collectors, and in one particular embodiment, the first current collector 101 and/or the second current collector 201 are composite current collectors.

Taking the first current collector 101 as an example, as shown in fig. 1, 2, 4, 6 and 7, the first composite current collector includes a first polymer layer 1011 and a first metal layer 1012 on both surfaces of the first polymer layer. Taking the second current collector 201 as an example, as shown in fig. 1, 3, 5 and 6, the second current collector includes a second polymer layer 2011 and second metal layers 2012 located on two surfaces of the second polymer layer.

When the first current collector 101 and/or the second current collector 201 have the above-described structural composition, the safety of the battery cell can be further improved and the cost can be reduced.

Since the current collector extension (the first current collector extension 102 or the second current collector extension 202) is extended from one end of the current collector (the first current collector 101 or the second current collector 201), the current collector extension corresponds to the structural composition of the current collector.

When the current collector is the above-described composite current collector, since the welding marks connecting the current collector extensions are provided in the thickness direction of the current collector extension (the first current collector extension 102 or the second current collector extension 202), two metal layers in one composite current collector are connected by the welding marks. For example, when the first conductive member 301 is disposed between at least two adjacent first current collector extensions 102, the contact internal resistance between the first current collector extensions 102 and the first tab 105 can be further reduced when the first tab is connected to the first current collector extensions 102, so as to improve the conductivity of the battery.

The specific choice of materials for the first polymer layer 1011 and the second polymer layer 2011 is not limited, and may be any polymer as is conventional in the art.

The specific choice of materials for the first metal layer 1012 and the second metal layer 2012 is not limited in the present utility model. When at least one of the first electrode plate 1 and the second electrode plate 2 is a positive electrode plate, the material of the metal layer in the composite current collector corresponding to the positive electrode plate is aluminum or the like, and when at least one of the first electrode plate 1 and the second electrode plate 2 is a negative electrode plate, the material of the metal layer in the composite current collector corresponding to the negative electrode plate is copper, nickel or the like.

In order to improve the safety of the battery cell, a metal protection layer 401 is disposed on at least one side of the battery cell in the stacking direction, and the thickness of the metal protection layer 401 is greater than the sum of the thicknesses of the first metal layers or the sum of the thicknesses of the second metal layers.

That is, the battery cell has two opposite sides in the stacking direction, wherein at least one side is the metal protection layer 401. That is, one metal protection layer 401 may be provided at one outer side of the battery cell, or one metal protection layer 401 may be provided at each of two outer sides of the battery cell.

The material of the metal protection layer 401 is not limited, and can be determined according to the specific selection of the electrode plate (the first electrode plate or the second electrode plate, hereinafter referred to as the adjacent electrode plate) closest to the metal protection layer 401, when the adjacent electrode plate of the metal protection layer 401 is the positive electrode plate, the current collector materials of the metal protection layer 401 and the negative electrode plate are consistent, specifically copper foil, nickel foil and the like; when the adjacent electrode plate of the metal protection layer 401 is a negative electrode plate, the metal protection layer 401 is identical to the current collector of the positive electrode plate in material selection, specifically aluminum foil.

In the battery cell, the thickness of the metal protection layer is greater than or equal to the thickness of the first electrode slice, or the thickness of the metal protection layer is greater than or equal to the thickness of the second electrode slice, which is beneficial to exerting the protection function of the metal protection layer 401 to the greatest extent.

Further, at least one layer of membrane 5 is further included between the metal protection layer 401 and the electrode plate closest to the metal protection layer 401, so as to prevent the metal protection layer 401 from contacting with the electrode plate closest to the metal protection layer 401 to cause short circuit of the battery cell after thermal shrinkage of the membrane.

The metal protection layer 401 can protect the battery cell. In order to achieve excellent safety performance of the battery while having good energy density, in one embodiment of the present utility model, the metal protection layer 401 is provided with an active layer 402 on a side close to the first current collector extension 102 in the lamination direction. At this time, the metal protection layer 401 and the active layer 402 are stacked, and the active layer 402 is located closer to the center of the cell than the metal protection layer 401.

The material of the active layer 402 is not limited, and can be determined according to the specific selection of the electrode plate (the first electrode plate or the second electrode plate, hereinafter referred to as the adjacent electrode plate) closest to the metal protection layer 401, when the adjacent electrode plate of the metal protection layer 401 is the positive electrode plate, the material of the active layer 402 is consistent with the material of the active material layer of the negative electrode plate; when the adjacent electrode sheet of the metal protection layer 401 is a negative electrode sheet, the material selection of the active layer 402 is identical to the material selection of the active material layer of the positive electrode sheet.

The active layer 402 is provided corresponding to the active material layer of the adjacent electrode sheet. The size of the active layer 402 is not limited in the present utility model, and may be determined according to the specific selection of the electrode sheet closest to the active layer 402. When the electrode sheet closest to the active layer 402 is the positive electrode sheet, the size of the active layer 402 may exceed the size of the positive electrode sheet body closest thereto; when the electrode sheet closest to the active layer 402 is a negative electrode sheet, the size of the active layer 402 is smaller than the size of the negative electrode sheet body.

Further, a diaphragm is arranged on one side of the active layer, which is close to the center of the battery cell.

Further, as shown in fig. 6, the cell further includes a metal cap extension 4012. The metal cap layer 401 has opposite ends in the longitudinal direction, and the metal cap layer extension 4012 is formed by starting from at least a part of the end surface of one end of the metal cap layer 401 in the longitudinal direction and extending in a direction away from the other end of the metal cap layer 401. Further, as shown in fig. 1 and 6, the metal protection layer 401 includes an active portion 4011 and a metal protection layer extension 4012, an active layer 402 is provided on a side of the active portion 4011 adjacent to the first current collector extension 102, and the metal protection layer extension 4012 is not provided with an active layer.

The metal cap extensions 4012 correspond to the current collector extensions (either the first current collector extension 102 or the second current collector extension 202) with each other (i.e., the projections of each metal cap extension 4012 and current collector extension on either separator maximize overlap under incident light parallel to the lamination direction). Illustratively, as shown in fig. 6, 7, the metal cap extension 4012 corresponds to the first current collector extension 102.

As shown in fig. 6 and 7, when the polarity of the metal protection layer is the same as that of the first electrode sheet, the metal protection layer extension portion is disposed corresponding to the first current collector extension portion; the metal protection layer extension part is connected with the first current collector extension part through a first welding mark; as shown in fig. 1 and 3, when the polarity of the metal protection layer is the same as that of the second electrode sheet, the metal protection layer extension portion and the second current collector extension portion are disposed correspondingly; the metal protection layer extension is connected with the second current collector extension through a second welding print.

Specifically, a third conductive member 303 is provided between the metal cap extension 4012 and the current collector extension (the first current collector extension 102 or the second current collector extension 202) corresponding to each other. As shown in fig. 6 and 7, a third conductive member 303 is disposed between the metal protection layer extension portion 4012 and the adjacent first current collector extension portion 102, the first tab 105 is located on a surface of the metal protection layer extension portion 4012 away from the central position of the battery cell, at this time, the first solder mark 106 connects the metal protection layer extension portion 4012, the first tab 105 and each first current collector extension portion 102, and a first protrusion 107 is disposed on a side of the first tab 105 away from the metal protection layer extension portion 4012. At this time, the metal protection layer extension 4012 can not only protect the third conductive member 303, but also fully utilize the conductive performance of the metal protection layer extension 4012, and the metal protection layer extension 4012 can be connected with the first tab 105 in combination with the first current collector extension 102, so as to further improve the conductive performance. As shown in fig. 1 and 3, a third conductive member 303 is disposed between the metal protection layer extension portion 4012 and the adjacent second current collector extension portions 202, the second electrode tab 205 is located on a surface of the metal protection layer extension portion 4012 away from the central position of the battery cell, at this time, the second solder mark 206 connects the metal protection layer extension portion 4012, the second electrode tab 205 and each second current collector extension portion 202, and a second protrusion 207 is disposed on a side of the second electrode tab 205 away from the metal protection layer extension portion. At this time, the metal protection layer extension 4012 can not only play a role of protecting the third conductive member 303, but also make full use of the conductive performance of the metal protection layer extension 4012, and the metal protection layer extension 4012 can be connected with the second tab 205 in combination with the second current collector extension 202, thereby further improving the conductive performance. Further, a first insulating adhesive layer covering the first welding mark is arranged on one side of the first electrode lug, which is far away from the center of the battery cell, and the first insulating adhesive layer is connected with the extending part of the metal protection layer; or, one side of the second lug far away from the center of the battery core is provided with a second insulating adhesive layer covering the second welding mark, and the second insulating adhesive layer is connected with the extending part of the metal protection layer.

The thickness of the first current collector 101, the second current collector 201, the first polymer layer 1011, the second polymer layer 2011, the first metal layer 1012, the second metal layer 2012, the first conductive member 301, and the second conductive member 302 is not limited, and may be specifically selected according to practical situations. For example, the thicknesses of the first and second current collectors 101 and 201 are each independently selected from 0.003mm to 0.05mm, the thicknesses of the first and second polymer layers 1011 and 2011 are each independently selected from 0.001mm to 0.05mm, the thicknesses of the first and second metal layers 1012 and 2012 are each independently selected from 0.0005mm to 0.03mm, and the thicknesses of the first and second conductive members 301 and 302 are each independently selected from 0.005mm to 0.05mm.

A diaphragm 5 is interposed between the adjacent first electrode sheet 1 and second electrode sheet 2 to separate the first electrode sheet 1 and second electrode sheet 2. The diaphragm 5 allows free passage of lithium ions on the one hand and plays an insulating role on the other hand, so that insulation between the first electrode plate 1 and the second electrode plate 2 can be realized, and internal short circuit of the battery is avoided.

To further ensure that the first electrode sheet 1 and the second electrode sheet 2 are not in contact, both ends of the separator 5 extend beyond both ends of the first electrode sheet body 10 and the second electrode sheet body 20, respectively, in the length direction. It will be appreciated that the edges of the first and second pole piece bodies 10, 20 are located inside the edges of the separator 5 in the stacking direction, avoiding internal shorting of the pole piece contacts of opposite polarity.

In one embodiment, the dimensions of the separator 5 in the length direction and the width direction are respectively 0.1mm to 10mm beyond the dimensions of the first electrode sheet 1, or the dimensions of the separator 5 in the length direction and the width direction are respectively 0.1mm to 10mm beyond the dimensions of the second electrode sheet 2.

In one embodiment, the cell further comprises adjacent first and second membranes 501, 502, at least one first membrane 501 and at least one second membrane 502 being connected by a membrane connection 503; one end of the diaphragm connecting portion 503 is connected to one end of the first diaphragm 501, and the other end of the diaphragm connecting portion 503 is connected to one end of the second diaphragm 502 by bypassing the side end face sandwiching the electrode sheet; the sandwiched electrode sheet is the first electrode sheet 1 or the second electrode sheet 2 between the first separator 501 and the second separator 502.

In the present utility model, the cell further includes a first membrane 501 and a second membrane 502 adjacent to each other. Adjacent here means that there is no other membrane between the adjacent first membrane 501 and second membrane 502. At this time, only the first electrode tab 1 or the second electrode tab 2 is provided between the adjacent first separator 501 and second separator 502.

The diaphragm connecting portion 503 has two ends, one end of the diaphragm connecting portion 503 is connected to one end of the first diaphragm 501, and the other end is connected to one end of the second diaphragm 502 by bypassing the electrode sheet. The first separator 501 has two ends in the longitudinal direction, namely, one end a far from the first current collector extension portion and the other end B near the first current collector extension portion, the end a being connected to the separator connection portion, and the second separator 502 has two ends in the longitudinal direction, namely, a C end corresponding to the end a in the stacking direction and a D end corresponding to the end B in the stacking direction, respectively, and the other end of the separator connection portion 503 is connected to the C end. At this time, the diaphragm connecting portion 503 wraps the end face, corresponding to AC, of the electrode plate sandwiched between the first diaphragm 501 and the second diaphragm 502, so that the positioning accuracy of the electrode plate sandwiched can be ensured, the process efficiency can be improved, the electrode plate and the diaphragm can be prevented from shaking left and right, contact of the electrode plates with opposite polarities can be avoided, and the safety performance of the battery can be improved.

One end of the first diaphragm 501 and one end of the second diaphragm 502 are both ends in the longitudinal direction.

The end faces of the electrode plates are clamped by the adjacent first diaphragm 501, the adjacent second diaphragm 502 and the adjacent diaphragm connecting part 503, so that the positioning accuracy of the electrode plates can be guaranteed, the processing efficiency can be accelerated, the electrode plates can be prevented from being clamped, the diaphragms can be prevented from shaking left and right, the electrode plates with opposite polarities are prevented from being contacted, and the safety performance of the battery is improved.

The specific positions of the first diaphragm 501 and the second diaphragm 502 are not limited in the present utility model, as long as adjacent ones are satisfied. At this time, the electrode sheet is the first electrode sheet 1 or the second electrode sheet 2 located between the first separator 501 and the second separator 502.

The connection mode of the first separator 501 and the second separator 502 through the separator connection part is not limited in the utility model, and the conventional thermal compounding process in the field can be adopted, for example, the first separator 501, the first electrode plate 1 and the second separator 502 finish surface thermal compounding under the action of a hot press roller, in the thermal compounding process, one end of each of the first separator 501 and the second separator 502 extends to the outer edge part of the first electrode plate 1, so that one end of each of the first separator 501 and the second separator 502 far away from the first current collector extension part 102 is thermally compounded and bonded into a whole to form a continuous separator connection part 503, and the other end of each of the first separator 501 and the second separator 502 is respectively connected with two surfaces of the first current collector extension part 102.

Further, the boundary of the diaphragm connecting portion is located outside the boundary of the sandwiched electrode plate, and it can be understood that the boundary of the diaphragm connecting portion is located outside the boundary of the first electrode plate or the second electrode plate, the projection of the first conductive member is not coincident with the projection of the diaphragm connecting portion, and the projection of the second conductive member is not coincident with the projection of the diaphragm connecting portion. The projection described above refers to a projection onto the diaphragm in the thickness direction.

Generally, the electrode plate is rectangular in shape, sharp corners are formed at four corners, the separator is easy to pierce, curling is easy to occur, and safety of the battery is influenced. As shown in fig. 8, in order to improve the safety performance of the battery, at least one corner of the first pole piece body 10 and/or the second pole piece body 20 of the present utility model is provided with an arc-shaped notch.

In one embodiment, at least one corner of the first pole piece body 10 is provided with a first notch 6, and the first notch 6 is composed of a plurality of arc line segments 61. For example, four corners of the first pole piece body are rounded corners formed by two arc line segments.

In another embodiment, at least one corner of the second pole piece body 20 is provided with a second notch, and the second notch is composed of a plurality of arc line segments.

The number of the arc segments 61 is not limited, and may be, for example, 1 to 5. The radius of curvature of each circular arc segment 61 is independently selected from 0.01mm to 10mm.

The specific choices of the first electrode sheet 1 and the second electrode sheet 2 are not limited in the present utility model, as long as one of them is a positive electrode sheet and the other is a negative electrode sheet. In order to avoid lithium precipitation, the size of the positive electrode sheet body is smaller than that of the negative electrode sheet body in the length direction and the width direction. For example, the size of the negative electrode sheet body exceeds the positive electrode sheet body by 0.1mm to 10mm in the longitudinal direction and/or the width direction.

As shown in fig. 1 and 4, when the first electrode sheet 1 is a positive electrode sheet and the second electrode sheet 2 is a negative electrode sheet, the size of the second electrode sheet body 20 is larger than that of the first electrode sheet body 10, and it is understood that the projection of the second electrode sheet body 20 onto the separator 5 along the stacking direction covers the projection of the first electrode sheet body 10 onto the separator 5 along the stacking direction.

Specifically, at least one end of the second pole piece body 20 in the length direction exceeds at least one end of the first pole piece body 10 in the length direction. Further, both ends of the second pole piece body 20 in the length direction respectively exceed both ends of the first pole piece body 10 in the length direction.

In one embodiment of the utility model, the extension part of the current collector of the positive plate is provided with the ceramic layer close to the body of the positive plate, and the dimension of the ceramic layer 104 in the length direction is 0.01-10 mm, so that the contact between the part of the body of the negative plate, which exceeds the body of the positive plate, and the extension part of the current collector of the positive plate can be avoided, and the safety performance of the battery cell is influenced.

In the present utility model, the above-mentioned cell may be a laminated cell or a wound cell.

The utility model also provides a battery, which comprises the battery core. Specifically, the battery for charge/discharge can be formed by mounting the above-described battery cells together with the protection circuit inside the battery case 9. Since the cell is the storage part in the battery, the quality of the cell directly determines the quality of the battery.

According to the battery cell and the battery provided by the utility model, the first conductive piece 301 is arranged between the adjacent first current collector extension parts 102, the first conductive piece 301 can enable the adjacent first current collector extension parts 102 to realize electric conduction, meanwhile, the first current collector extension parts 102 and the first tab 105 are enabled to realize electric conduction by utilizing the first welding marks 106, and the contact internal resistance between the first current collector extension parts 102 and the first tab 105 can be reduced under the combined action of the first conductive piece 301 and the first welding marks 106, so that the conductive performance of the battery is improved.

It should be noted that, the numerical values and the numerical ranges related to the embodiments of the present utility model are approximate values, and may have a certain range of errors under the influence of the manufacturing process, and those errors may be considered to be negligible by those skilled in the art.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the same; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the utility model.

The embodiments of the present utility model have been described above. However, the present utility model is not limited to the above embodiment. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims (18)

1. The battery cell is characterized by comprising N first electrode plates, M second electrode plates opposite to the first electrode plates in electrical property and first electrode lugs, wherein the first electrode plates and the second electrode plates are alternately stacked; n is more than or equal to 2, M is more than or equal to 1;

The first electrode plate comprises a first electrode plate body and a first current collector extension part connected with a first current collector in the first electrode plate body; the first current collector extension part and the first tab are stacked; the first electrode plate is provided with a first welding mark for connecting the first current collector extension part and the first tab;

the second electrode plate comprises a second plate body and a second current collector extension part connected with a second current collector in the second plate body;

wherein a first conductive member is disposed between at least two adjacent first current collector extensions.

2. The cell of claim 1, wherein at least one side of the cell is provided with a metal protection layer in a lamination direction;

the metal protection layer includes a metal protection layer extension;

the polarity of the metal protection layer is the same as that of the first electrode plate, and the metal protection layer extension part and the first current collector extension part are correspondingly arranged;

the metal protection layer extension is connected with the first current collector extension through the first welding mark.

3. The cell of claim 2, wherein the first tab stack is disposed on a surface of the metal protection layer extension away from a central location of the cell;

The surface of the first tab, which is far away from the extending part of the metal protection layer, is also provided with a first bulge, and the first bulge is connected with the first welding mark.

4. The cell of claim 1, further comprising a second tab, m+.2, the second current collector extension being stacked with the second tab; the second electrode sheet is provided with a second welding mark for connecting the second current collector extension part and a second lug;

a second conductive member is disposed between at least two adjacent second current collector extensions.

5. The cell of claim 4, wherein at least one side of the cell is provided with a metal protection layer in a lamination direction;

the polarity of the metal protection layer is the same as that of the second electrode plate, and the metal protection layer extension part and the second current collector extension part are correspondingly arranged;

the metal protection layer extension is connected with the second current collector extension through the second welding mark.

6. The cell of claim 5, wherein the second tab stack is disposed on a surface of the metal cap layer extension away from a central location of the cell;

the surface of the second lug far away from the extending part of the metal protection layer is also provided with a second bulge, and the second bulge is connected with the second welding mark.

7. The cell of claim 2 or 5, wherein a third conductive member is disposed between the metallic protection layer extension and the first current collector extension, or

A third conductive member is disposed between the metallic protection layer extension and the second current collector extension.

8. The cell of any one of claims 2-6, wherein a side of the first tab away from the center of the cell is provided with a first insulating layer covering the first solder, and the first insulating layer is connected to the metal protection layer extension; and/or the number of the groups of groups,

one side of the second electrode ear far away from the center of the battery core is provided with a second insulating adhesive layer covering the second welding mark, and the second insulating adhesive layer is connected with the extending part of the metal protection layer.

9. The cell of any one of claims 3-6, wherein,

the first welding mark is a welding mark of laser welding;

the second weld is an ultrasonic welded weld.

10. The cell of claim 9, wherein the first protrusion has a thickness of 0-0.1 mm; and/or the number of the groups of groups,

the thickness of the second bulge is 0-0.1 mm; and/or the number of the groups of groups,

the thickness of the first welding mark is 0.01 mm-30 mm; and/or the number of the groups of groups,

the thickness of the second welding mark is 0.01 mm-30 mm; and/or the number of the groups of groups,

The tensile force between the first tab and the first current collector extension part is not less than 2N, and the foil sticking area is 30% -100%; and/or the number of the groups of groups,

the tensile force between the second lug and the second current collector extension part is not less than 2N, and the sticky foil area is 30% -100%.

11. The cell of claim 10, wherein the relative difference in thickness of the first protrusion and the second protrusion is no greater than 40%; and/or the number of the groups of groups,

the relative difference between the thicknesses of the first welding mark and the second welding mark is not more than 50%; and/or the number of the groups of groups,

the relative difference between the pull force between the first tab and the first current collector extension and the pull force between the second tab and the second current collector extension is no greater than 30%; and/or the number of the groups of groups,

the relative difference in the sticky foil area between the first tab and the first current collector extension and the sticky foil area between the second tab and the second current collector extension is no greater than 30%.

12. The cell of claim 1, wherein the first current collector is a first composite current collector comprising a first polymer layer and a first metal layer on both surfaces of the first polymer layer; and/or the number of the groups of groups,

the second current collector is a second composite current collector, and the second composite current collector comprises a second polymer layer and second metal layers positioned on two surfaces of the second polymer layer.

13. The cell of claim 2 or 5, wherein the thickness of the metal protection layer is equal to or greater than the thickness of the first electrode tab, or

The thickness of the metal protection layer is larger than or equal to that of the second electrode plate.

14. The cell of claim 2 or 5, wherein the metal protection layer is provided with an active layer on a side of the first current collector extension.

15. The cell according to claim 2 or 5, wherein a diaphragm is arranged on one side of the metal protection layer, which is close to the central position of the cell;

the end of the diaphragm is bonded to the end of the metal protection layer.

16. The cell of claim 1, wherein a separator is sandwiched between adjacent first and second electrode sheets;

the separator includes adjacent first and second separators, at least one of which is connected to the first electrode sheet or the second electrode sheet.

17. The cell of claim 16, wherein the boundary of the separator connection is located outside the boundary of the first electrode tab or the second electrode tab,

the projection of the first conductive piece is not overlapped with the projection of the diaphragm connecting part, and the projection of the second conductive piece is not overlapped with the projection of the diaphragm connecting part.

18. A battery comprising a cell according to any one of claims 1-17.