CN117678102A - Reel core and battery - Google Patents

Abstract

A winding core and a battery, wherein the winding core comprises: the positive plate is provided with a positive plate paste removing part, and the positive plate paste removing part is a part of the positive plate, which is absent at the winding starting end of the winding core compared with the negative plate; a negative electrode sheet including a negative electrode current collector (10), a negative electrode active material layer (20), and a gap filler (30); the negative electrode current collector (10) comprises a first side surface and a second side surface which are opposite, wherein at least one side surface of the first side surface and the second side surface is provided with a negative electrode active material layer (20); the gap filler (30) is disposed on one of the first side surface and the second side surface at a position corresponding to the winding start end of the winding core. The flatness of the inner ring of the winding core is improved, the expansion deformation of the battery caused by uneven stress in the cyclic expansion process is reduced, capacity attenuation and battery failure caused by edge lithium precipitation are also reduced, and the use effect of the battery is further improved.

Description

Reel core and battery

The present application claims priority from the chinese patent office, application No. 202222450151.X, application name "a negative electrode sheet and battery" and the chinese patent office, application No. 202222650473.9, application name "a negative electrode sheet and battery" filed on 10 month 09 of 2022, application No. 15, the entire contents of which are incorporated herein by reference.

Technical Field

The application relates to the technical field of batteries, in particular to a winding core and a battery.

Background

Lithium ion batteries are widely put into daily life use of people, wherein the lithium ion batteries have the characteristics of high specific energy, low self-discharge, long cycle life, no pollution to the environment and the like, and along with the rapid development of lithium ion battery technology, higher requirements are put forward for the energy density, the rapid charging capability and the charging and discharging multiplying power of the lithium ion batteries.

In the prior art, the conventional winding type lithium ion battery structure cannot meet the requirement of quick charging, so that the position of a tab needs to be moved to the position of 3/4, 1/3 or 1/2 of the positive and negative pole pieces, and in order to prevent edge lithium precipitation, the positive pole pieces need to be cut, so that the positive pole pieces are covered by the negative pole pieces, gaps exist in the positions of the winding cores, uneven inner rings of the winding cores are caused, and the using effect of the battery is poor.

Disclosure of Invention

The application provides a roll up core and battery to solve among the prior art battery because of the poor problem of battery result of rolling up core inner circle unevenness and lead to.

To achieve the above object, the present application provides a winding core, which is characterized by comprising: the positive plate is provided with a positive plate paste removing part, and the positive plate paste removing part is a part of the positive plate, which is absent at the winding starting end of the winding core compared with the negative plate; the negative electrode plate comprises a negative electrode current collector, a negative electrode active material layer and a gap filler; the negative electrode current collector comprises a first side surface and a second side surface which are opposite, and at least one side surface of the first side surface and the second side surface is provided with the negative electrode active material layer; the gap filler is arranged at a position corresponding to the winding starting end of the winding core on one side surface of the first side surface and the second side surface, and fills a gap between the positive electrode plate and the negative electrode plate at the winding starting end of the winding core.

Optionally, a length of the anode active material layer of the first side in the anode current collector extending direction is greater than a length of the anode active material layer of the second side in the anode current collector extending direction, and a length of the anode current collector is greater than a length of the anode active material layer of the first side.

Optionally, the gap filler is disposed on the first side surface, and at least a portion of the gap filler is fixed to the anode active material layer.

Optionally, the first end of the gap filler is flush with the first end of the anode active material layer of the first side, the first end of the anode active material layer of the first side is an end of the anode active material layer near the winding start end of the winding core, and the first end of the gap filler is an end of the gap filler near the tail of the anode current collector.

Alternatively, a part of the gap filler is fixed to the anode active material layer, and another part is fixed to the anode current collector.

Optionally, the gap filler is disposed on the second side surface, and the length of the negative electrode current collector is greater than the length of the negative electrode active material layer disposed on the second side surface, and the gap filler is fixed with the negative electrode current collector.

Optionally, the first end of the negative electrode active material layer of the first side face is opposite to the center of the first end and the second end of the gap filler; the first end of the negative electrode active material layer of the first side is the end of the negative electrode active material layer, which is close to the winding starting end of the winding core, the first end of the gap filler is the end, which is close to the tail of the negative electrode current collector, and the second end of the gap filler is the end, which is far away from the tail of the negative electrode current collector.

Optionally, the first end of the negative electrode active material layer of the first side is flush with the first end of the gap filler; alternatively, the first end of the anode active material layer is flush with the second end of the gap filler; the first end of the negative electrode active material layer of the first side is the end of the negative electrode active material layer, which is close to the winding starting end of the winding core, the first end of the gap filler is the end, which is close to the tail of the negative electrode current collector, and the second end of the gap filler is the end, which is far away from the tail of the negative electrode current collector.

Optionally, the gap filler is a glue.

Optionally, the adhesive tape has a through hole structure.

Optionally, the adhesive tape comprises an insulating layer and an adhesive layer, wherein the adhesive layer is fixed with the negative plate, and the insulating layer is positioned on one side of the adhesive layer, which is away from the negative plate.

Optionally, the thickness value of the adhesive layer is greater than or equal to 2 μm, and the thickness value of the adhesive layer is less than or equal to a first preset value; and/or, the thickness value of the insulating layer is more than or equal to 2 mu m, and the thickness value of the insulating layer is less than or equal to a first preset value; the first preset value is larger than or equal to half of the thickness value of the positive plate paste removal, reduced by 10 mu m, and smaller than or equal to half of the thickness value of the positive plate paste removal, reduced by 4 mu m.

Optionally, the thickness of the adhesive tape is 0.52-0.55 times of the thickness of the positive plate.

Optionally, the length of the adhesive tape along the extending direction of the negative electrode plate is 1.8-2.2 times of the length of the positive electrode plate for paste withdrawal.

Optionally, the gap filler is a paste layer provided with protrusions in a direction perpendicular to the anode active material layer.

Optionally, the paste layer and the anode active material layer disposed on the first side are in an integrated structure; or the anode active material layer and the paste layer are laminated together in a double-layer structure.

Optionally, the paste layer includes at least one of artificial graphite, natural graphite, mesophase carbon microspheres, soft carbon, hard carbon, and organic polymer compound carbon.

Optionally, the length of the paste coating layer along the extending direction of the negative electrode sheet is the same as the length of the positive electrode sheet for paste removal.

Optionally, the height of the protrusion of the paste coating layer is 1.03-1.08 times the thickness of the positive electrode sheet.

Optionally, the paste coating layer includes at least one of a pressure sensitive adhesive, a ceramic, and a polymer layer.

Optionally, the polymer layer comprises at least one of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyimide, and polyurethane, and/or; the pressure sensitive adhesive comprises at least one of rubber, silica gel, acrylic ester and polyurethane.

The present application also provides a battery comprising a winding core according to the first aspect of the present application.

In the application, in order to prevent lithium from being separated from the edge in the related art, the positive plate is cut, and the cut negative plate covers the positive plate, so that a gap is reserved at the position of the battery winding core, and the inner ring of the winding core is uneven; the flatness of the battery at the inner ring of the winding core is improved, the expansion deformation of the battery caused by uneven stress in the cyclic expansion process is reduced, and the capacity attenuation and the battery failure caused by edge lithium precipitation are also reduced, so that the use effect of the battery is improved.

It should be understood that the description of this section is not intended to identify key or critical features of the embodiments of the application or to delineate the scope of the application. Other features of the present application will become apparent from the description that follows.

Drawings

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

Fig. 1 is a schematic view of a structure of a related art wound battery;

fig. 2a is one of schematic structural diagrams of a negative plate when the gap filler provided in the embodiment of the present application is a glue paste;

fig. 2b is a schematic view of the structure of the negative electrode sheet shown in fig. 2a in a wound state;

fig. 3 is a second schematic structural diagram of the negative electrode sheet when the gap filler provided in the embodiment of the present application is a glue paste;

fig. 4 is a third schematic structural diagram of the negative electrode sheet when the gap filler provided in the embodiment of the present application is a glue;

Fig. 5a is a schematic structural diagram of a negative plate when the gap filler provided in the embodiment of the present application is a glue;

fig. 5b is a schematic view of the structure of the negative electrode sheet shown in fig. 5a in a wound state;

fig. 6 is a schematic diagram of a negative electrode sheet when the gap filler provided in the embodiment of the present application is a glue;

fig. 7 is a schematic structural diagram of a negative plate when the gap filler provided in the embodiment of the present application is a glue;

fig. 8 is a schematic structural diagram of a negative plate when the gap filler provided in the embodiment of the present application is a glue;

fig. 9 is a schematic structural diagram of a negative electrode sheet when the gap filler provided in the embodiment of the present application is a paste layer;

fig. 10 is a ninth schematic structural view of the negative electrode sheet when the gap filler provided in the embodiment of the present application is a paste layer;

FIG. 11 is a schematic view of a negative electrode sheet with a gap filler provided in an embodiment of the present application as a paste layer;

FIG. 12 is a schematic diagram of a negative electrode sheet with a gap filler as a paste layer according to an embodiment of the present disclosure;

fig. 13 is a schematic diagram showing a structure of a negative electrode sheet when the gap filler provided in the embodiment of the present application is a paste layer.

Reference numerals illustrate:

10-negative electrode current collector;

20-a negative electrode active material layer;

30-gap filler.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

The terms "first," "second," and the like in embodiments of the present application are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The winding core of the first aspect of the application comprises a positive plate and a negative plate, wherein the positive plate and the negative plate can be wound to form the winding core, and a diaphragm is arranged between the positive plate and the negative plate.

The positive plate is provided with a positive plate paste removing agent, the positive plate paste removing agent is one end of the positive plate, which is close to the center of the winding core, compared with the part lacking of the negative plate, and therefore a gap is formed between the positive plate and the negative plate at one end, which is close to the center of the battery winding core. In other words, the positive electrode tab paste removal is a portion of the positive electrode tab that is absent at the winding start end of the winding core compared to the negative electrode tab, the positive and negative electrode tabs having slits at the winding start end of the battery winding core. It is understood that since the winding core is wound from inside to outside during winding, the winding start end herein refers to the start position of the winding core during winding, and is also the end of the center line of the winding core in the thickness direction along the horizontal direction, or the end of the positive electrode sheet and the negative electrode sheet at the innermost side of the winding core.

As shown in fig. 2a to 13, the negative electrode sheet includes a negative electrode current collector 10, a negative electrode active material layer 20, and a gap filler 30; the anode current collector 10 includes opposite first and second sides, at least one of which is provided with an anode active material layer 20; the gap filling body 30 is disposed at one end of one of the first side surface and the second side surface, which is close to the center of the battery winding core, and the gap filling body 30 is used for filling a gap between the positive electrode plate and the negative electrode plate, which is close to one end of the center of the battery winding core.

In this embodiment, the above-mentioned negative electrode sheet includes a negative electrode current collector 10, a negative electrode active material layer 20, and a gap filler 30, where the gap filler 30 is disposed on one of the first side and the second side and is close to one end of the center of the battery winding core, and the gap filler 30 can fill a gap between the positive electrode sheet and the negative electrode sheet near one end of the center of the battery winding core, so as to improve the flatness of the inner ring of the winding core, reduce expansion deformation of the battery caused by uneven stress in the cyclic expansion process, and on the other hand, reduce capacity attenuation and battery failure caused by edge lithium precipitation, and further improve the use effect of the battery.

Some specific embodiments of the winding core of the present application are described below.

As shown in fig. 2a to 8, in the negative electrode sheet provided in the first embodiment of the present application, the gap filler 30 is a glue paste 30. The anode current collector 10 includes opposite first and second sides, at least one of which is provided with an anode active material layer 20; the glue paste 30 has a through hole structure; the adhesive 30 is disposed at one end of one of the first side and the second side, which is close to the center of the battery winding core, and the adhesive 30 is used for filling a gap between the positive electrode plate and the negative electrode plate, which is close to the center of the battery winding core.

In this embodiment, above-mentioned negative pole piece is including negative pole current collector 10, negative pole active material layer 20 and glue subsides 30, glue subsides 30 set up in one of them side of above-mentioned first side and above-mentioned second side to be close to the one end at above-mentioned battery core center of rolling up, glue subsides 30 can fill the gap of the one end that positive pole piece and above-mentioned negative pole piece are close to the center of above-mentioned battery core of rolling up, thereby improve the roughness of battery at the core inner circle of rolling up, reduce the battery because of the expansion deformation that the atress is uneven in the cyclic expansion process, on the other hand, also reduced the capacity decay and the battery inefficacy that lead to because of the edge separates lithium, and then promoted the result of use of battery.

The adhesive 30 may also have the above-mentioned through hole structure, through the setting of the above-mentioned through hole structure, the transmission of lithium ions in the battery after the battery is coiled and processed can be improved, so the setting of the above-mentioned through hole structure of the adhesive 30 reduces the influence to the internal reaction or process of the battery to a certain extent, on the other hand, if the adhesive 30 needs to be bent, the setting of the above-mentioned through hole structure can reduce the bulge or unevenness of the adhesive 30 caused by bending.

Referring to fig. 2a, 2b and 3, the position of the through hole structure at the paste 30 may be determined according to the position of the paste 30 at the negative electrode current collector 10 or the negative electrode active material layer 20, in which case the through hole structure is disposed at the left side of the paste 30 in the direction shown in fig. 2a, and in which case the through hole structure is disposed at the center of the paste 30 in the direction shown in fig. 2 a.

It should be noted that, the above-mentioned through hole structure can be according to user's demand and add the setting, does not set up under the condition of above-mentioned through hole structure at the sticky note 30, still can improve the roughness of battery at the core inner circle of rolling up, reduces the battery and because of the uneven expansion deformation that leads to of atress in the cyclic expansion process, and this application embodiment is not repeated.

It should be understood that the adhesive 30 may be disposed on the first side or the second side, and after the adhesive 30 is disposed on both sides of the negative electrode active material layer 20, the gap of the inner ring of the winding core may be effectively filled by winding, so as to reduce the possibility of lithium precipitation at the edge of the battery.

The adhesive sheet 30 may be directly fixed to the negative electrode current collector 10, or a part of the adhesive sheet 30 may be fixed to the negative electrode current collector 10, and another part of the adhesive sheet 30 may be fixed to the negative electrode active material layer 20.

The specific steps can be as follows: if the adhesive 30 is disposed on one of the two sides, along the longer side of the length of the negative electrode active material layer 20 in the extending direction of the negative electrode current collector 10, a part of the adhesive 30 may be adhered and fixed to the negative electrode current collector 10, and another part of the adhesive may be adhered and fixed to the negative electrode active material layer 20, and after the negative electrode sheet and the positive electrode are matched and wound, the flatness of the battery at the inner ring of the winding core may be improved by the adhesive 30.

If the adhesive 30 is disposed on one of the two sides, along the short side of the length of the negative electrode active material layer 20 in the extending direction of the negative electrode current collector 10, the adhesive 30 may be completely adhered and fixed to the negative electrode current collector 10, and after the negative electrode sheet and the positive electrode are matched and wound, the adhesive 30 may still improve the flatness of the battery at the inner ring of the winding core.

It should be understood that the length and thickness of the adhesive 30 may be set according to the structural dimension of the battery at the inner ring of the winding core, or may be set according to the dimension of the positive electrode sheet paste-removing in the battery, where the positive electrode sheet paste-removing is the end of the positive electrode sheet near the center of the winding core of the battery, and the embodiment of the application is not limited as compared with the missing part of the negative electrode sheet.

Alternatively, in the case where the anode active material layer 20 is disposed on the first side and the second side, the length of the anode active material layer 20 in the extending direction of the anode current collector 10 on the first side is greater than the length of the anode active material layer 20 in the extending direction of the anode current collector 10 on the second side;

in the case that the paste 30 is disposed on one side of the first side, and the length of the negative electrode current collector 10 is greater than the length of the negative electrode active material layer 20 disposed on the first side, a portion of the paste 30 is fixed to the negative electrode active material layer 20, and another portion of the paste 30 is fixed to the negative electrode current collector 10;

In the case where the paste 30 is disposed on one side of the second side surface, and the length of the negative electrode current collector 10 is greater than the length of the negative electrode active material layer 20 disposed on the first side surface, the paste 30 is fixed to the negative electrode current collector 10.

In this embodiment, under the precondition that the length of the anode active material layer 20 in the extending direction of the first side along the anode current collector 10 is greater than the length of the anode active material layer 20 in the extending direction of the second side along the anode current collector 10, the arrangement mode and the position of the glue paste 30 are changed due to the different lengths of the anode active material layer 20 on two sides, and by arranging the glue paste 30 on two different sides of the anode current collector, the limitation of the arrangement position of the glue paste 30 is reduced, the requirement of improving the flatness of the inner ring of the winding core can be met at the same time, and the use effect of the battery is further improved.

When the adhesive 30 is disposed on the first side, the adhesive 30 after the winding process is located at the outer side of the tail of the negative electrode current collector 10, and when the adhesive 30 is disposed on the second side, the adhesive 30 after the winding process is located at the inner side of the tail of the negative electrode current collector 10.

Alternatively, referring to fig. 5, in the case that the paste 30 is disposed on one side of the second side, and the length of the negative electrode current collector 10 is greater than the length of the negative electrode active material layer 20 disposed on the first side, the paste 30 is fixed to the negative electrode current collector 10, wherein the first end of the negative electrode active material layer 20 is symmetric to the first side with respect to the negative electrode current collector 10 as a symmetry axis, and the positions symmetric to the first side are located at the centers of the first end of the paste 30 and the second end of the paste 30;

The end of the anode active material layer 20 on the first side, which is close to the center of the battery winding core, is the first end of the anode active material layer 20, the first end of the adhesive tape 30 is the end of the adhesive tape 30, which is close to the tail of the anode current collector 10, and the second end of the adhesive tape 30 is the end of the adhesive tape 30, which is close to the anode active material layer 20 (i.e., the end of the adhesive tape 30, which is far away from the tail of the anode current collector 10).

In this embodiment, the adhesive 30 is all attached to and fixed on the negative current collector 10, and the first end of the negative active material layer 20 is symmetrical to the first side surface with the negative current collector 10 as a symmetry axis, and the positions symmetrical to the first side surface are located at the centers of the first end of the adhesive 30 and the second end of the adhesive 30.

Alternatively, referring to fig. 6, in the case where the paste 30 is disposed at one side of the second side, and the length of the negative electrode current collector 10 is greater than the length of the negative electrode active material layer 20 disposed at the first side, the paste 30 is fixed to the negative electrode current collector 10, wherein the first end of the negative electrode active material layer 20 and the first end of the paste 30 are flush in the extending direction of the negative electrode current collector 10;

The end of the negative electrode active material layer 20 on the first side, which is close to the center of the battery winding core, is a first end of the negative electrode active material layer 20, and the first end of the glue 30 is an end of the glue 30, which is close to the tail of the negative electrode current collector 10.

In this embodiment, the adhesive 30 is all attached to and fixed on the negative current collector 10, and the first end of the negative active material layer 20 and the first end of the adhesive 30 are flush along the extending direction of the negative current collector 10, by the arrangement of this structure, after the positive plate and the negative plate are coiled, the adhesive 30 can play a supporting role on the bent negative current collector 10, but the adhesive 30 cannot bend along with the negative current collector 10, the whole of the adhesive 30 cannot deform, the adhesive 30 is in a single-layer shape, the pressure born by the pole piece can be effectively averaged, the flatness of the surface of the winding core is improved, and the expansion deformation of the winding core caused by uneven stress in the cyclic expansion process of the winding core is reduced.

Alternatively, referring to fig. 7, in the case where the paste 30 is disposed at one side of the second side, and the length of the negative electrode current collector 10 is greater than the length of the negative electrode active material layer 20 disposed at the first side, the paste 30 is fixed to the negative electrode current collector 10, wherein the first end of the negative electrode active material layer 20 and the second end of the paste 30 are flush in the extending direction of the negative electrode current collector 10;

The end of the anode active material layer 20 on the first side, which is close to the center of the battery winding core, is a first end of the anode active material layer 20, and the second end of the adhesive tape 30 is an end of the adhesive tape 30, which is close to the anode active material layer 20 (i.e., the second end of the adhesive tape 30 is an end of the adhesive tape 30, which is far away from the tail of the anode current collector 10).

In this embodiment, the adhesive 30 is all attached to and fixed on the negative current collector 10, and the first end of the negative active material layer 20 and the second end of the adhesive 30 are flush along the extending direction of the negative current collector 10, and by the arrangement of this structure, after the positive electrode sheet and the negative electrode sheet are wound, the adhesive 30 is arranged at the tail of the negative current collector 10 subjected to bending treatment, and the whole of the adhesive 30 is not deformed, and the adhesive 30 is in a single-layer shape, so that the pressure born by the electrode sheet can be effectively averaged, the flatness of the surface of the winding core is improved, and the expansion deformation of the winding core due to uneven stress in the cyclic expansion process is reduced.

In the structure shown in fig. 7, the position of the adhesive in the battery winding core in fig. 7 may be the same as the position of the adhesive in the battery winding core in fig. 6, but in both cases, the fixing surfaces of the adhesive are different, and in the case of the view of fig. 6 and 7, the adhesive in fig. 6 is finally fixed to the negative electrode current collector downward, and the adhesive in fig. 7 is finally fixed to the negative electrode current collector upward.

Optionally, the sticker 30 includes an insulating layer and a glue layer.

In this embodiment, glue subsides 30 can be including two-layer structure, wherein, one deck is above-mentioned insulating layer, and another layer is above-mentioned glue film, and the glue film is fixed with the negative pole piece, and the insulating layer is located the one side of deviating from the negative pole piece of glue film, and the influence of glue subsides 30 to battery own inner structure can be reduced in the setting of above-mentioned insulating layer, and the setting stability of glue subsides 30 can be improved to above-mentioned glue film, reduces the possibility that glue subsides 30 drops, through the setting of this structure for when glue subsides 30 keep fixed stability, also can reduce the influence to battery normal operating.

The thickness of the insulating layer and the thickness of the adhesive layer may be set according to the thickness of the positive electrode sheet in the battery, and the lengths of the insulating layer and the adhesive layer along the length direction of the positive electrode sheet may be set according to the paste withdrawal of the positive electrode sheet.

In addition, the insulating layer may be an insulating material selected to be suitable for use in a battery, for example: the polymer layer can be made of one insulating material or a mixture of a plurality of insulating materials.

Likewise, the glue layer may be a glue material selected for use in a battery, for example: the suitable colloid material can reduce the possibility of falling off in the internal environment of the battery, and the colloid layer can be made of one colloid material or a plurality of colloid materials by mixing, and the material selection of the insulating layer and the colloid layer is not limited.

Optionally, the thickness value of the adhesive layer is greater than or equal to 2 μm, and the thickness value of the adhesive layer is less than or equal to a first preset value;

the first preset value is larger than or equal to half of the thickness value of the positive plate paste withdrawal, and is reduced by 10 mu m, and the first preset value is smaller than or equal to half of the thickness value of the positive plate paste withdrawal, and is 4 mu m, wherein the positive plate paste withdrawal is that one end of the positive plate, which is close to the center of the battery winding core, is compared with the part lacking of the negative plate.

In this embodiment, in the manufacturing process of the adhesive layer, the thickness of the adhesive layer needs to be set between 2 μm and the first preset value, for example: the thickness of the adhesive layer may be selected to be between 2 μm and half of the thickness of the positive electrode tab paste removal by 10 μm, and alternatively, in another possible embodiment, the thickness of the adhesive layer may be selected to be between half of the thickness of the positive electrode tab paste removal by 10 μm and half of the thickness of the positive electrode tab paste removal by 4 μm, which is given by way of example only and not limitation.

When the thickness relation with the positive electrode sheet is defined, the thickness of the insulating layer may be determined according to the thickness relation between the positive electrode sheet and the adhesive layer, and the thickness of the insulating layer may not be defined or calculated.

Optionally, the thickness value of the insulating layer is greater than or equal to 2 μm, and the thickness value of the insulating layer is less than or equal to a first preset value;

the first preset value is larger than or equal to half of the thickness value of the positive plate paste withdrawal, and is reduced by 10 mu m, and the first preset value is smaller than or equal to half of the thickness value of the positive plate paste withdrawal, and is 4 mu m, wherein the positive plate paste withdrawal is that one end of the positive plate, which is close to the center of the battery winding core, is compared with the part lacking of the negative plate.

In this embodiment, in the process of manufacturing the insulating layer, it is necessary to set the thickness of the insulating layer between 2 μm and the first preset value, for example: the thickness of the insulating layer may be selected to be between 2 μm and half the thickness of the positive electrode tab paste removal by 10 μm, and in another possible embodiment, the thickness of the insulating layer may be selected to be between half the thickness of the positive electrode tab paste removal by 10 μm and half the thickness of the positive electrode tab paste removal by 4 μm, which is given by way of example only and not limitation.

When the thickness relation with the positive electrode sheet is defined, the thickness of the adhesive layer may be determined according to the thickness relation between the positive electrode sheet and the adhesive layer and the thickness of the insulating layer, and the thickness of the adhesive layer does not need to be defined and calculated.

Optionally, the insulating layer includes at least one of a polymer layer, a textured paper, and a glassine paper.

In this embodiment, the insulating layer is made of one or more of a polymer layer, a textured paper and a glassine paper, and the polymer layer, the textured paper and the glassine paper can be applied to electronic components and have the characteristics of high temperature resistance, good chemical solvent resistance, high adhesion, soft adhesion, no residual glue after tearing, and the like, so that the requirements in the negative electrode sheet are met, the adhesive tape 30 is suitable for the internal structure of a battery, the flatness of the inner ring of the winding core is improved, and the use effect of the battery is further improved.

Optionally, the polymer layer comprises at least one of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyimide, and polyurethane.

Optionally, the glue layer comprises at least one of rubber, silicone, acrylate, and polyurethane.

Optionally, the thickness of the sticker 30 is 0.52-0.55 times the thickness of the positive electrode sheet.

In this embodiment, the thickness of the adhesive sheet 30 is 0.55 times or less the thickness of the positive electrode sheet, and the thickness of the adhesive sheet 30 is 0.52 times or more the thickness of the positive electrode sheet, for example: the thickness of the adhesive 30 may be 0.53 times the thickness of the positive electrode sheet, and alternatively, in another possible embodiment, the thickness of the adhesive 30 may be 0.55 times the thickness of the positive electrode sheet, which is given by way of example only and not limitation.

Optionally, the length of the adhesive 30 along the extending direction of the negative electrode sheet is 1.8-2.2 times the length of the paste removed by the positive electrode sheet, where the paste removed by the positive electrode sheet is one end of the positive electrode sheet near the center of the battery winding core, compared with the missing part of the negative electrode sheet.

In this embodiment, the length of the adhesive 30 in the extending direction of the negative electrode sheet is 1.8 times or more the length of the positive electrode sheet paste removal, and the length of the adhesive 30 in the extending direction of the negative electrode sheet is 2.2 times or less the length of the positive electrode sheet paste removal, for example: the length of the paste 30 in the extending direction of the negative electrode sheet may be 1.9 times the length of the paste removed from the positive electrode sheet, and alternatively, in another possible embodiment, the length of the paste 30 in the extending direction of the negative electrode sheet may be 2.1 times the length of the paste removed from the positive electrode sheet, which is given as an example and not a limitation.

As shown in fig. 9-13, in the negative electrode sheet provided in the second embodiment of the present application, the gap filler 30 is a paste layer 30; the anode current collector 10 includes opposite first and second sides, at least one of which is provided with an anode active material layer 20; the paste layer 30 is disposed at one end of one of the first side and the second side, which is close to the center of the battery winding core, and the paste layer 30 is provided with protrusions in a direction perpendicular to the negative electrode active material layer 20, and the paste layer 30 is used to fill up a gap between the positive electrode sheet and the negative electrode sheet, which is close to the center of the battery winding core.

In this embodiment, the negative electrode sheet includes a negative electrode current collector 10, a negative electrode active material layer 20, and a paste coating layer 30, where the paste coating layer 30 is disposed on the first side and fixed to the negative electrode active material layer 20, and the paste coating layer 30 is provided with a protrusion in a direction perpendicular to the negative electrode active material layer 20 and has a certain protrusion height, and in addition, the paste coating layer 30 is flush with one end of the negative electrode active material layer 20 near the center of the battery winding core, and of course, the paste coating layer 30 may also be disposed on the second side and fixed to the negative electrode current collector 10, and the paste coating layer 30 can fill a gap between the positive electrode sheet and one end of the negative electrode sheet near the center of the battery winding core, thereby improving the flatness of the inner ring of the battery winding core, reducing the expansion deformation of the battery caused by uneven stress in the cyclic expansion process, and reducing the capacity attenuation and battery failure caused by edge lithium precipitation, and improving the use effect of the battery.

In the case where the anode active material layer is provided on the first side surface and the second side surface, the length of the anode active material layer in the direction in which the anode current collector extends on the first side surface is longer than the length of the anode active material layer in the direction in which the anode current collector extends on the second side surface.

The paste layer 30 may be fixed to the anode active material layer 20 as a single structure, or the paste layer 30 may be formed integrally with the anode active material layer 20, and when the paste layer 30 is fixed to the anode active material layer 20 as a single structure, the paste layer 30 may fill up a gap between the positive electrode sheet and the anode sheet near the center end of the battery winding core, and when the paste layer 30 and the anode active material layer 20 are formed integrally, the paste layer 30 may also fill up a gap between the positive electrode sheet and the anode sheet near the center end of the battery winding core.

It should be understood that the length and thickness of the paste coating layer 30 may be set according to the structural dimension of the battery at the inner ring of the winding core, or may be set according to the dimension of the positive electrode sheet paste-removing in the battery, where the positive electrode sheet paste-removing is the end of the positive electrode sheet near the center of the winding core of the battery, compared to the missing portion of the negative electrode sheet, which is not limited in this embodiment of the present application.

The paste layer 30 may be an active material or an inactive material, and the material may be selected according to the actual battery requirements or user requirements, and if the active material is an active material, the material of the paste layer 30 may be the same active material as the negative electrode active material layer 20. The embodiments of the present application are not limited in this regard.

If the paste layer 30 is made of an active material, it may be made of a different active material from the negative electrode active material layer 20.

Alternatively, if the paste layer 30 is made of an active material, the content of the active material in the paste layer 30 may be consistent with the active material content of the anode active material layer 20, for example: if the active material content in the anode active material layer 20 is 97.2%, the active material content in the paste layer 30 may be set at 97.2%. Of course, the active material content in the paste layer 30 may be set to other content, which is not limited to the embodiment of the present application.

Alternatively, in the case where the anode active material layer 20 is disposed on the first side and the second side, the length of the anode active material layer 20 in the extending direction of the anode current collector 10 on the first side is greater than the length of the anode active material layer 20 in the extending direction of the anode current collector 10 on the second side;

The paste layer 30 is disposed on the first side and fixed to the anode active material layer 20, wherein the paste layer 30 is flush with an end of the anode active material layer 20 near the center of the battery roll core.

In this embodiment, the paste coating layer 30 is entirely attached to the negative electrode active material layer 20 on the first side, and the paste coating layer 30 is flush with the negative electrode active material layer 20 near the central end of the battery winding core, and by this configuration, after the winding treatment is performed on the positive electrode sheet and the negative electrode sheet, the paste coating layer 30 may play a role of filling the paste removing part of the positive electrode sheet, that is, play a supporting role, but the paste coating layer 30 will not bend along with the negative electrode current collector 10, and the whole of the paste coating layer 30 will not deform, thereby reducing the expansion deformation of the winding core caused by uneven stress in the cyclic expansion process.

Alternatively, referring to fig. 10, in the case where the anode active material layer 20 is disposed on the first side and the second side, the length of the anode active material layer 20 in the direction in which the first side extends along the anode current collector 10 is greater than the length of the anode active material layer 20 in the direction in which the second side extends along the anode current collector 10;

The paste layer 30 is disposed on the second side and fixed to the anode current collector 10, wherein the first end of the anode active material layer 20 and the first end of the paste layer 30 are flush in the extending direction of the anode current collector 10;

the end of the anode active material layer 20 of the first side, which is close to the center of the battery winding core, is a first end of the anode active material layer 20, and the first end of the paste layer 30 is an end of the paste layer 30, which is close to the tail of the anode current collector 10.

In this embodiment, the paste coating layer 30 is disposed on the second side and is all attached to the negative current collector 10, and the first end of the negative electrode active material layer 20 and the first end of the paste coating layer 30 are flush in the extending direction along the negative current collector 10, by this configuration, after the positive electrode sheet and the negative electrode sheet are wound, the paste coating layer 30 can play a supporting role on the bent negative current collector 10, but the paste coating layer 30 cannot bend along with the negative electrode current collector 10, the whole of the paste coating layer 30 will not deform, the paste coating layer 30 is in a single layer shape, the pressure born by the electrode sheet can be effectively averaged, the flatness of the surface of the winding core is improved, and the expansion deformation of the winding core due to uneven stress in the cyclic expansion process of the winding core is reduced.

Alternatively, referring to fig. 11, in the case where the anode active material layer 20 is disposed on the first side and the second side, the length of the anode active material layer 20 in the direction in which the first side extends along the anode current collector 10 is greater than the length of the anode active material layer 20 in the direction in which the second side extends along the anode current collector 10;

the paste layer 30 is disposed on the second side and fixed to the anode current collector 10, wherein a first end of the anode active material layer 20 and a second end of the paste layer 30 are flush in the extending direction of the anode current collector 10;

the end of the negative electrode active material layer 20 of the first side, which is close to the center of the battery winding core, is a first end of the negative electrode active material layer 0, and the second end of the paste layer 30 is an end of the paste layer 30, which is close to the negative electrode active material layer 20.

In this embodiment, the paste coating layer 30 is disposed on the second side and is all attached to the negative current collector 10, and the first end of the negative electrode active material layer 20 and the second end of the paste coating layer 30 are flush along the extending direction of the negative current collector 10, and by this configuration, after the positive electrode sheet and the negative electrode sheet are wound, the paste coating layer 30 is disposed on the tail of the negative current collector 10 after the bending treatment, the whole of the paste coating layer 30 will not deform, the paste coating layer 30 is in a single layer shape, so that the pressure borne by the pole sheet can be effectively averaged, the flatness of the surface of the winding core is improved, and the expansion deformation of the winding core due to uneven stress in the cyclic expansion process of the winding core is reduced.

In fig. 10, the position of the paste layer in the battery core may be the same as the position of the paste layer in fig. 11, compared with the structure shown in fig. 11, but the fixing surfaces of the paste layers are different in both cases.

Taking the perspective of fig. 10 and 11 as an example, the paste layer in fig. 10 is finally fixed downward to the negative electrode current collector, and the paste layer in fig. 11 is finally fixed upward to the negative electrode current collector.

Alternatively, referring to fig. 12, the paste layer 30 is integrally formed with the anode active material layer 20 provided on the first side; or (b)

The anode active material layer 20 and the paste layer 30 are combined into a double-layer structure.

In this embodiment, the paste layer 30 and the anode active material layer 20 disposed on the first side are integrally formed, and the process flow is reduced by integrally forming the paste layer 30 and the anode active material layer 20, so that the efficiency of manufacturing the anode sheet is improved without affecting the normal use of the anode sheet, and the anode active material layer 20 and the paste layer 30 may be formed in a double-layered structure, wherein when the paste layer 30 is fixed to the anode active material layer 20 in a separate structure, the paste layer 30 is formed in a double-layered structure, and the gap between the anode sheet and the anode sheet near the center of the battery winding core is filled.

In the case of coating in the battery manufacturing process, the paste layer 30 and the negative electrode active material layer 20 may be integrated by controlling the discharge rate of the coating die, and the negative electrode sheet manufactured by this method may be made of the same material as the paste layer 30 and the negative electrode active material layer 20.

Optionally, the paste layer 30 includes at least one of artificial graphite, natural graphite, mesophase carbon microspheres, soft carbon, hard carbon, and organic polymer compound carbon.

Optionally, the length of the paste coating layer 30 along the extending direction of the negative electrode sheet is the same as the paste removing length of the positive electrode sheet, which is the portion of the positive electrode sheet that is near the center of the winding core, compared to the portion of the negative electrode sheet that is missing.

In this embodiment, the length of the paste coating layer 30 along the extending direction of the negative electrode sheet is set to be identical to the paste removing length of the positive electrode sheet, and by the arrangement of this structure, the gap can be filled with the paste coating layer 30 without affecting the internal structure of the battery, and the influence on the normal operation of the battery is reduced.

Optionally, the height of the protrusion of the paste coating layer is 1.03-1.08 times the thickness of the positive electrode sheet.

In this embodiment, the thickness of the paste layer 30 is 1.08 times or less the thickness of the positive electrode sheet, and the thickness of the paste layer 30 is 1.03 times or more the thickness of the positive electrode sheet, for example: the thickness of the paste layer 30 may be 1.04 times the thickness of the positive electrode sheet, and alternatively, in another possible embodiment, the thickness of the paste layer 30 may be 1.07 times the thickness of the positive electrode sheet, which is given as an example and not a limitation.

Optionally, the paste layer 30 includes at least one of a pressure sensitive adhesive, a ceramic, and a polymer layer.

In this embodiment, the paste coating layer 30 is made of an inactive material including one or more of a pressure sensitive adhesive, a ceramic and a polymer layer, which reduces the influence on the internal structure and environment of the battery, does not affect the normal operation of the battery, and thus effectively improves the use effect of the battery while filling up the gap between the positive electrode sheet and the negative electrode sheet.

Optionally, the polymer layer comprises at least one of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyimide, and polyurethane, and/or;

the pressure sensitive adhesive comprises at least one of rubber, silica gel, acrylic ester and polyurethane.

In addition, the embodiment of the application also provides a battery, which comprises the winding core.

It should be noted that the battery can be applied to various electric devices, and the electric devices can be notebook computers, smart phones, new energy automobiles and other devices. The implementation manner of the embodiment of the battery is also suitable for the embodiment of the electronic device, and the same technical effects can be achieved, which is not described herein.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element. Furthermore, it should be noted that the scope of the methods and apparatus in the embodiments of the present application is not limited to performing the functions in the order discussed, but may also include performing the functions in a substantially simultaneous manner or in an opposite order depending on the functions involved, e.g., the described methods may be performed in an order different from that described, and various steps may also be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

The embodiments of the present application have been described above with reference to the accompanying drawings, but the present application is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those of ordinary skill in the art without departing from the spirit of the present application and the scope of the claims, which are also within the protection of the present application.

Claims (22)

1. A winding core, comprising:

the positive plate is provided with a positive plate paste removing part, and the positive plate paste removing part is a part of the positive plate, which is absent at the winding starting end of the winding core compared with the negative plate;

a negative electrode sheet including a negative electrode current collector (10), a negative electrode active material layer (20), and a gap filler (30);

the negative electrode current collector (10) comprises a first side surface and a second side surface which are opposite, and at least one side surface of the first side surface and the second side surface is provided with the negative electrode active material layer (20);

the gap filler (30) is arranged on one side surface of the first side surface and the second side surface and corresponds to the winding starting end of the winding core, and the gap filler (30) fills a gap between the positive electrode plate and the negative electrode plate at the winding starting end of the winding core.

2. The winding core according to claim 1, characterized in that the length of the anode active material layer (20) of the first side in the direction of extension of the anode current collector (10) is greater than the length of the anode active material layer (20) of the second side in the direction of extension of the anode current collector (10), the length of the anode current collector (10) being greater than the length of the anode active material layer (20) of the first side.

3. The winding core according to claim 2, wherein the gap filler (30) is provided on the first side surface, and at least a part of the gap filler (30) is fixed to the anode active material layer (20).

4. The winding core according to claim 3, characterized in that the first end of the gap filler (30) is flush with the first end of the negative electrode active material layer (30) of the first side,

the first end of the negative electrode active material layer (20) of the first side is the end of the negative electrode active material layer (20) close to the winding start end of the winding core, and the first end of the gap filler (30) is the end of the gap filler (30) close to the tail of the negative electrode current collector (10).

5. A winding core according to claim 3, characterized in that a part of the gap filler (30) is fixed to the negative electrode active material layer (20) and another part is fixed to the negative electrode current collector (10).

6. The winding core according to claim 2, wherein the gap filler (30) is provided on the second side surface, and the length of the anode current collector (10) is longer than the length of the anode active material layer (20) provided on the second side surface, and the gap filler (30) is fixed to the anode current collector (10).

7. The winding core according to claim 6, characterized in that the first end of the negative electrode active material layer (20) of the first side is opposite to the center of the first and second ends of the gap filler (30);

the first end of the negative electrode active material layer (20) of the first side is the end of the negative electrode active material layer (20) close to the winding starting end of the winding core, the first end of the gap filler (30) is the end close to the tail of the negative electrode current collector (10), and the second end of the gap filler (30) is the end far away from the tail of the negative electrode current collector (10).

8. The winding core according to claim 6, characterized in that the first end of the negative active material layer (20) of the first side is flush with the first end of the gap filler (30); or,

-the first end of the negative electrode active material layer (20) is flush with the second end of the gap filler (30);

the first end of the negative electrode active material layer (20) of the first side is the end of the negative electrode active material layer (20) close to the winding starting end of the winding core, the first end of the gap filler (30) is the end close to the tail of the negative electrode current collector (10), and the second end of the gap filler (30) is the end far away from the tail of the negative electrode current collector (10).

9. A winding core according to any of claims 1-3 and 5-8, characterized in that the gap filler (30) is a glue (30).

10. The winding core according to claim 9, characterized in that the glue (30) has a through-hole structure.

11. The winding core according to claim 9, characterized in that the glue (30) comprises an insulating layer and a glue layer, the glue layer being fixed to the negative plate, the insulating layer being located on the side of the glue layer facing away from the negative plate.

12. The winding core according to claim 11, wherein the thickness of the glue layer is greater than or equal to 2 μm and less than or equal to a first preset value; and/or, the thickness value of the insulating layer is more than or equal to 2 mu m, and the thickness value of the insulating layer is less than or equal to a first preset value;

the first preset value is larger than or equal to half of the thickness value of the positive plate paste removal, reduced by 10 mu m, and smaller than or equal to half of the thickness value of the positive plate paste removal, reduced by 4 mu m.

13. The winding core according to claim 9, characterized in that the thickness of the glue (30) is 0.52-0.55 times the thickness of the positive plate.

14. The winding core according to claim 9, characterized in that the length of the glue (30) in the direction of extension of the negative electrode sheet is 1.8-2.2 times the length of the positive electrode sheet paste withdrawal.

15. The winding core according to any one of claims 1 to 4, 6 and 8, characterized in that the gap filler (30) is a paste layer (30), the paste layer (30) being provided with protrusions in a direction perpendicular to the negative electrode active material layer (20).

16. The winding core according to claim 15, wherein the paste layer (30) is of unitary construction with the negative electrode active material layer (20) provided on the first side; or (b)

The negative electrode active material layer (20) and the paste layer (30) are combined into a double-layer structure.

17. The winding core according to claim 15, wherein the paste layer (30) comprises at least one of artificial graphite, natural graphite, mesophase carbon microspheres, soft carbon, hard carbon and organic polymer compound carbon.

18. The winding core according to claim 15, characterized in that the length of the paste layer (30) in the direction of extension of the negative electrode sheet is the same as the length of withdrawal of the positive electrode sheet.

19. A winding core according to claim 15, characterized in that the height of the protrusions of the paste layer (30) is 1.03-1.08 times the thickness of the positive plate.

20. The winding core according to claim 15, wherein the paste layer (30) comprises at least one of a pressure sensitive adhesive, a ceramic and a polymer layer.

21. The winding core according to claim 20, wherein the polymer layer comprises at least one of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyimide, and polyurethane, and/or;

the pressure sensitive adhesive comprises at least one of rubber, silica gel, acrylic ester and polyurethane.

22. A battery comprising a winding core according to any one of claims 1 to 21.