CN214378573U - Roll up core and laminate polymer battery - Google Patents

Abstract

The utility model provides a roll up core and laminate polymer battery relates to lithium cell technical field. The winding core comprises a negative plate, wherein a first adhesive paper layer covers the inner surface of a second bending area of the negative plate along the winding direction, and the two ends of the first adhesive paper layer are along the projection of the thickness direction of the winding core and the projection of the winding head end of the negative plate along the thickness direction of the winding core are connected or partially overlapped. Thereby the condition that the surface of the roll core is uneven is improved, and the flatness of the battery core is improved.

Description

Roll up core and laminate polymer battery

Technical Field

The utility model relates to a lithium cell technical field especially relates to a roll up core and laminate polymer battery.

Background

With the development of science and technology, the technology of lithium ion batteries is rapidly developed. Meanwhile, users also put higher requirements on the quick charging capability and the charging and discharging rate of the lithium ion battery, and the quick charging lithium battery becomes the development trend of consumer lithium ion batteries.

Whether the interface bonding of the lithium ion battery is good during high-rate charging can directly affect the long cycle life of the lithium ion battery, the expansion problem of the lithium ion battery and the deformation problem of the lithium ion battery. The key to whether the interface bonding of the lithium ion battery is good is whether the pressure borne by the lithium ion battery in the formation process is uniform, and the key to whether the pressure borne by the lithium ion battery in the formation process is uniform is whether the flatness of the whole battery cell in the design process of the battery cell is good, namely, the smaller the difference between the highest point and the lowest point on the surface of the battery cell is, the better the flatness of the battery cell is. The battery core comprises a winding core and a shell for packaging the winding core.

However, in the prior art, the unevenness of the surface of the winding core is serious, and the flatness of the battery cell is affected.

SUMMERY OF THE UTILITY MODEL

The utility model provides a roll up core and laminate polymer battery, this roll up the condition of core surface unevenness has obtained improving to be favorable to improving the roughness of electric core, and then be favorable to improving lithium ion battery's interface bonding effect, with the purpose of realizing improving lithium ion battery's long cycle life, inflation problem and deformation problem.

In a first aspect, the utility model provides a roll up core, including the negative pole piece, the negative pole piece has first adhesive paper layer along the internal surface cover in the second bending region of coiling direction, first adhesive paper layer's both ends are followed roll up the projection of the thickness direction of core, with the coiling head end of negative pole piece is followed the projection of the thickness direction of rolling up the core meets or the partial coincidence.

The utility model provides a roll up core includes the negative pole piece, through the internal surface covering first adhesive paper layer in the negative pole piece along the second bending region of coiling direction to make the projection of the thickness direction of rolling up the core along the both ends of first adhesive paper layer, meet or the partial coincidence along the projection of the thickness direction of rolling up the core with the coiling head end of negative pole piece. The thickness of the end, close to the bending area, of the winding core is increased, so that the thickness of the end, far away from the bending area, of the winding core is basically consistent with the thickness of the end, close to the bending area, of the winding core; and then be favorable to improving the condition of rolling up core surface unevenness, be favorable to improving the roughness of electric core, simultaneously, be favorable to improving the interface bonding effect of the battery after the formation, finally realize improving the long cycle life of battery, the purpose of inflation problem and deformation problem.

The winding core can optionally further comprise a negative electrode tab, the negative electrode tab comprises a negative electrode current collector and a negative electrode active layer, and the negative electrode active layer is coated on two opposite surfaces of the negative electrode current collector; the winding head end of the negative current collector is exposed in sequence along the winding direction to form a negative double-sided empty foil area and a negative single-sided empty foil area, and the negative tab is arranged in the negative double-sided empty foil area; the first adhesive paper layer is located in the negative electrode single-side empty foil area, and two ends of the first adhesive paper layer are connected with one end, close to the bending area, of the negative electrode tab.

According to the winding core, optionally, a concave portion is arranged on one surface of the first adhesive paper layer, which faces away from the negative single-sided empty foil area.

In the winding core, optionally, the thickness of the middle region of the concave part in the length direction of the negative electrode sheet is smaller than the thickness of the other regions of the concave part; and the thickness of the depressed part gradually increases from the middle area of the depressed part to both sides.

In the winding core described above, the thickness of the central region of the recess may be in a range of 3 μm to 8 μm.

In the winding core, optionally, the size of the opening of the concave part in the length direction of the negative electrode sheet ranges from 1mm to 5 mm.

In the winding core, optionally, the middle area of the concave part corresponds to the middle area of the negative single-sided empty foil region in the length direction of the negative electrode sheet.

The winding core as described above, optionally, further includes a negative electrode tab adhesive paper layer, the negative electrode tab adhesive paper layer covers the surface of the negative electrode tab, the size of the negative electrode tab adhesive paper layer in the length direction of the negative electrode tab is a first length, and the size of the negative electrode tab in the length direction of the negative electrode tab is a second length; the first length is greater than or equal to the second length.

The winding core optionally further comprises a positive plate and a positive tab assembly, wherein the positive plate comprises a positive current collector and a positive active layer, and the positive active layer is coated on two opposite surfaces of the positive current collector; the winding head end of the positive current collector is exposed to form a positive double-sided empty foil area, the positive tab assembly is arranged in the positive double-sided empty foil area and has a preset distance with the negative tab, and the negative tab is positioned between the positive tab assembly and the bending area; the two opposite sides in positive pole two-sided empty paper tinsel district all are provided with second adhesive paper layer, two the first end on second adhesive paper layer overlaps respectively and is lieing in the two opposite sides of anodal mass flow body the first end on positive pole active layer, two the second end on second adhesive paper layer all with keeping away from of anodal ear subassembly the one end of negative pole ear meets.

Optionally, the positive tab assembly includes a positive tab, a first positive tab adhesive paper layer, and a second positive tab adhesive paper layer, the first positive tab adhesive paper layer covers the surface of the positive tab, the second positive tab adhesive paper layer covers the surface of the positive double-sided empty foil area away from the positive tab, and the position of the second positive tab adhesive paper layer is opposite to the position of the first positive tab adhesive paper layer; and the second ends of the two second adhesive paper layers are respectively connected with one ends of the first positive tab adhesive paper layer and the second positive tab adhesive paper layer, which are far away from the negative tab.

According to the winding core, optionally, the second adhesive paper layer on the side of the positive electrode double-sided empty foil area, which is away from the positive electrode tab, and the second adhesive paper layer on the positive electrode tab are integrated.

According to the winding core, optionally, the second adhesive paper layer on the side of the positive electrode tab in the positive electrode double-sided empty foil area and the first adhesive paper layer on the positive electrode tab are integrated.

According to the winding core, optionally, two third adhesive paper layers are arranged at the winding tail end of the positive plate, the first ends of the two third adhesive paper layers are respectively lapped at the second ends of the positive active layers positioned on the two opposite surfaces of the positive current collector, and the projections of the second ends of the two third adhesive paper layers along the thickness direction of the winding core are connected with the projection of one end of the positive lug, far away from the negative lug, along the thickness direction of the winding core.

The winding core as described above, optionally, the sum of the thicknesses of the two second adhesive paper layers and the thicknesses of the two third adhesive paper layers is a first thickness value; the sum of the thickness of the positive tab, the thickness of the first positive tab adhesive paper layer and the thickness of the second positive tab adhesive paper layer is a second thickness value; the difference between the first thickness value and the second thickness value ranges between 80% and 120%.

The winding core as described above, optionally, further comprises a separator, wherein the separator is disposed between the positive electrode sheet and the negative electrode sheet; the sum of the thickness of the positive tab, the thickness of the first positive tab adhesive paper layer, the thickness of the second positive tab adhesive paper layer, the two times of the thickness of the positive current collector and the two times of the thickness of the diaphragm is a third thickness value; twice the thickness of the first ply is a fourth thickness value; the difference between the third thickness value and the fourth thickness value ranges between 80% and 120%.

The winding core can optionally further comprise a fourth adhesive paper layer, the fourth adhesive paper layer is attached to at least one side of the outer surface of the winding core, and the fourth adhesive paper layer is located between the negative electrode lug and the positive electrode lug.

In a second aspect, the utility model provides a laminate polymer battery, including the shell and as above roll up the core, roll up the core encapsulate in the shell.

The utility model provides a laminate polymer battery includes the shell and rolls up the core, rolls up the core and encapsulates in the shell. Under the condition that the unevenness on the surface of the roll core is improved, the flatness of the soft package battery is also improved, so that the interface bonding effect of the soft package battery after formation is improved, and the purposes of improving the long cycle life, the expansion problem and the deformation problem of the soft package battery are finally achieved.

The winding core comprises a negative plate, a first adhesive paper layer covers the inner surface of a second bending area of the negative plate along the winding direction, and the projection of the two ends of the first adhesive paper layer along the thickness direction of the winding core is connected with or partially overlapped with the projection of the winding head end of the negative plate along the thickness direction of the winding core. The thickness of the end, close to the bending area, of the winding core is increased, so that the thickness of the end, far away from the bending area, of the winding core is basically consistent with the thickness of the end, close to the bending area, of the winding core; and then be favorable to improving the condition of rolling up core surface unevenness, be favorable to improving the roughness of electric core, simultaneously, be favorable to improving the interface bonding effect of the battery after the formation, finally realize improving the long cycle life of battery, the purpose of inflation problem and deformation problem.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive labor.

Fig. 1 is a top view of a winding core according to an embodiment of the present invention;

FIG. 2 is an enlarged view of the central region of the winding core of FIG. 1;

fig. 3 is a front view of a negative electrode plate of a winding core according to an embodiment of the present invention;

fig. 4 is a top view of a negative electrode sheet of a winding core according to an embodiment of the present invention;

FIG. 5 is an enlarged view taken at A in FIG. 4;

fig. 6 is a front view of a winding core according to an embodiment of the present invention;

fig. 7 is a cross-sectional view at B-B in fig. 6.

Description of reference numerals:

20-a winding core; 21-negative plate; 211-negative current collector; 2111-negative pole double-sided empty foil area; 2112-negative single-sided empty foil region; 21121-bending zone; 212-negative active layer; 22-negative tab; 23-positive plate; 231-a positive current collector; 2311-positive electrode double-sided empty foil area; 232-positive electrode active layer; 24-the anodal tab; 31-a first adhesive paper layer; 311-a recess; 32-a second adhesive paper layer; 33-a third adhesive paper layer; 34-a fourth adhesive paper layer; 35-a protective adhesive paper layer; 36-sealing adhesive paper layer; 41-negative tab adhesive paper layer; 42-negative tab cushion; 51-a first positive tab adhesive paper layer; 52-second positive tab adhesive paper layer.

Detailed Description

In the related art, the winding core mainly comprises a negative plate, a positive plate, a diaphragm, a negative electrode tab and a positive electrode tab, wherein the negative electrode tab is welded at the winding head end of the negative plate, the positive electrode tab is welded at the winding head end of the positive plate, and the negative plate, the positive plate and the diaphragm are stacked according to a preset sequence and are wound in the same direction from the winding head end to finally form the winding core. Due to the fact that the thickness of different parts of the winding core is different due to factors such as the structure of the positive/negative pole piece, the structure of the positive/negative pole lug, the welding position of the positive/negative pole lug, the arrangement mode of the diaphragm and the like, the flatness of the winding core is poor, the interface bonding effect of the formed battery is affected, the long cycle life of the battery is shortened, and the expansion problem and the deformation problem of the battery are aggravated.

In order to solve the technical problem, the utility model provides a roll up core should roll up the core and include the negative pole piece, through the internal surface covering first adhesive paper layer at the negative pole piece along the second bending region of coiling direction to make the projection of the thickness direction of rolling up the core at the both ends of first adhesive paper layer, meet or the partial coincidence along the projection of the thickness direction of rolling up the core with the coiling head end of negative pole piece. The thickness of the end, close to the bending area, of the winding core is increased, so that the thickness of the end, far away from the bending area, of the winding core is basically consistent with the thickness of the end, close to the bending area, of the winding core; and then be favorable to improving the condition of rolling up core surface unevenness, be favorable to improving the roughness of electric core, simultaneously, be favorable to improving the interface bonding effect of the battery after the formation, finally realize improving the long cycle life of battery, the purpose of inflation problem and deformation problem.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Example one

Fig. 1 is a top view of a winding core according to an embodiment of the present invention; FIG. 2 is an enlarged view of the central region of the winding core of FIG. 1; fig. 3 is a front view of a negative electrode plate of a winding core according to an embodiment of the present invention; fig. 4 is a top view of a negative electrode sheet of a winding core according to an embodiment of the present invention; FIG. 5 is an enlarged view taken at A in FIG. 4; fig. 6 is a front view of a winding core according to an embodiment of the present invention; fig. 7 is a cross-sectional view at B-B in fig. 6.

Referring to fig. 1 to 6, the present embodiment provides a winding core, where the winding core 20 includes a negative electrode sheet 21, an inner surface of a second bending region 21121 of the negative electrode sheet 21 along a winding direction is covered with a first adhesive paper layer 31, and a projection of two ends of the first adhesive paper layer 31 along a thickness direction of the winding core is connected with or partially overlapped with a projection of a winding head end of the negative electrode sheet 21 along the thickness direction of the winding core.

The winding core provided by the embodiment comprises the negative electrode plate, wherein the first adhesive paper layer covers the inner surface of the second bending area of the negative electrode plate along the winding direction, and the projection of the two ends of the first adhesive paper layer along the thickness direction of the winding core is connected with or partially overlapped with the projection of the winding head end of the negative electrode plate along the thickness direction of the winding core. The thickness of the end, close to the bending area, of the winding core is increased, so that the thickness of the end, far away from the bending area, of the winding core is basically consistent with the thickness of the end, close to the bending area, of the winding core; and then be favorable to improving the condition of rolling up core surface unevenness, be favorable to improving the roughness of electric core, simultaneously, be favorable to improving the interface bonding effect of the battery after the formation, finally realize improving the long cycle life of battery, the purpose of inflation problem and deformation problem.

Optionally, the winding core 20 further includes a negative electrode tab 22, the negative electrode sheet 21 includes a negative electrode collector 211 and a negative electrode active layer 212, and the negative electrode active layer 212 is coated on opposite sides of the negative electrode collector 211. For example, the negative electrode current collector 211 is usually made of copper foil, and of course, the negative electrode current collector 211 may be made of other materials according to actual needs as long as the requirements of the winding core 20 can be met.

The winding head end of the negative current collector 211 is exposed in turn along the winding direction to form a negative double-sided empty foil area 2111 and a negative single-sided empty foil area 2112. Wherein, the winding head end refers to the end of the winding start; the negative double-sided empty foil region 2111 refers to a region where both opposite sides of the negative current collector 211 are not covered with the negative active layer 212; when one of the two opposite surfaces of the negative electrode current collector 211 is covered with the negative electrode active layer 212, and the other surface is not covered with the negative electrode active layer 212, the surface not covered with the negative electrode active layer 212 is the negative electrode single-sided empty foil region 2112. The negative single-sided empty foil area 2112 is located on one side of the negative current collector 211 facing the center of the winding core 20, and the negative single-sided empty foil area 2112 is connected between the negative double-sided empty foil area 2111 and the negative current collector 211 coated with the negative active layer 212 on opposite sides. The negative tab 22 is disposed within the negative double-sided empty foil region 2111.

During the winding process, the second bending region 21121 of the negative electrode sheet 21 in the winding direction is located in the negative single-sided empty foil region 2112, i.e., the first adhesive paper layer 31 is located in the negative single-sided empty foil region 2112. The bent region 21121 is opposite to the end of the winding head end of the negative electrode current collector 211, and the end of the winding head end of the negative electrode current collector 211 may extend into the bent region 21121 or be located outside the bent region 21121. The two ends of first adhesive paper layer 31 are connected to one end of negative tab 22 near bending region 21121.

For example, the first adhesive paper layer 31 may include a substrate layer and an adhesive layer, and the first adhesive paper layer 31 is bonded to the surface of the bending region 21121 through the adhesive layer; the material of substrate layer mainly includes: one or more of cast polypropylene, uniaxially stretched polypropylene, biaxially stretched polypropylene, polyethylene, polyester fiber, or polyvinyl chloride; the glue layer mainly comprises the following materials: one or more of water glue, oil glue, hot melt glue, natural rubber or synthetic rubber; the thickness of the glue layer can be set to be 2 mu m, and the thickness of the base material layer can be set according to actual needs. Illustratively, the dimension of the first adhesive paper layer along the length direction of the negative electrode sheet is equal to 2 × the distance between one end of the negative electrode tab facing the bending region and one end of the bending region away from the negative electrode tab.

The surface of the first bending region 21121 of the negative single-sided empty foil region 2112 in the winding direction is covered with the first adhesive paper layer 31, and two ends of the first adhesive paper layer 31 are connected with one end, close to the bending region 21121, of the negative tab 22, so that the thickness of the winding core 20 at one end, located at the negative tab 22, of the negative tab 22 towards the bending region 21121 is increased, and the thickness of the winding core 20 at one end, located at the negative tab 22 towards the bending region 21121 is basically consistent with the thickness of the winding core 20 in the region provided with the negative tab 22; and then be favorable to improving the condition that rolls up core 20 surface unevenness, be favorable to improving the roughness of electric core, simultaneously, be favorable to improving the interface bonding effect of the battery after the formation, finally realize improving the long cycle life of battery, the purpose of inflation problem and deformation problem.

Optionally, one side of the first adhesive paper layer 31 departing from the negative single-sided empty foil area 2112 is provided with a recessed portion 311, and the recessed portion 311 is arranged to prevent the first adhesive paper layer 31 from being bent along with the bent area 21121, and the side of the first adhesive paper layer 31 departing from the negative single-sided empty foil area 2112 is mutually extruded at the bent position to increase the thickness of the winding core 20 corresponding to the bent position, so that the surface unevenness of the winding core 20 can be improved.

Optionally, the thickness of the middle region of the concave portion 311 in the length direction of the negative electrode sheet 21 is smaller than the thickness of the other regions of the concave portion 311; and the thickness of the recess 311 is gradually increased from the middle region of the recess 311 to both sides. For example, the cross-sectional profile of the recess 311 may be angular or arc. Thereby be favorable to guaranteeing that first adhesive paper layer 31 keeps even along the thickness after the middle zone is buckled, and then be favorable to improving the condition of rolling up core 20 surface unevenness.

Optionally, the thickness of the middle region of the recess 311 ranges from 3 μm to 8 μm. Illustratively, the thickness of the middle region of the recess 311 may be set to 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, or any value between 3 μm and 8 μm according to actual needs. Thereby be favorable to guaranteeing that the thickness of first adhesive paper layer 31 after buckling keeps even, and then be favorable to improving the condition of rolling up core 20 surface unevenness.

Alternatively, the size range of the opening of the recess 311 in the length direction of the negative electrode sheet 21 is 1mm to 5 mm. Illustratively, the size of the opening of the recess 311 in the length direction of the negative electrode sheet 21 may be set to any value between 1mm, 2mm, 4mm, 5mm, or 1mm to 5mm according to actual needs. Preferably, the size of the opening of the recess 311 in the longitudinal direction of the negative electrode sheet 21 is set to 3 mm. Thereby be favorable to guaranteeing that the thickness of first adhesive paper layer 31 after buckling keeps even, and then be favorable to improving the condition of rolling up core 20 surface unevenness.

Optionally, the middle region of the recess 311 corresponds to the middle region of the negative one-sided empty foil region 2112 in the length direction of the negative electrode tab 21. In a normal case, the negative single-sided empty foil region 2112 is bent to form a bent region 21121 in the middle region of the negative plate 21 in the length direction, and the middle region of the recessed portion 311 of the first adhesive paper layer 31 corresponds to the middle region of the negative single-sided empty foil region 2112 in the length direction of the negative plate 21, so as to ensure that the middle region of the recessed portion 311 is bent along with the bent region 21121, thereby being beneficial to ensuring that the bent thickness of the first adhesive paper layer 31 is uniform, and further being beneficial to improving the uneven surface of the winding core 20.

Optionally, the winding core 20 further comprises a negative electrode tab adhesive paper layer 41, and the negative electrode tab adhesive paper layer 41 covers the surface of the negative electrode tab 22 to prevent burrs on the surface of the negative electrode tab 22 from piercing the separator between the negative electrode tab 21 and the positive electrode tab 23 to cause an internal short circuit in the winding core 20. The dimension of negative electrode tab adhesive paper layer 41 in the length direction of negative electrode tab 21 is greater than or equal to the dimension of negative electrode tab 22 in the length direction of negative electrode tab 21. The size range of the negative electrode tab 22 in the length direction of the negative electrode sheet 21 may be 5mm to 10 mm; the thickness of negative electrode tab 22 may range from 45 μm to 110 μm; the size range of the negative electrode tab adhesive paper layer 41 in the length direction of the negative electrode tab 21 can be 10mm to 20 mm; the thickness of negative electrode tab adhesive paper layer 41 may range from 5 μm to 16 μm. For example, when the size of the negative electrode tab adhesive paper layer 41 in the length direction of the negative electrode tab 21 is greater than the size of the negative electrode tab 22 in the length direction of the negative electrode tab 21, the sizes of the negative electrode tab adhesive paper layer 41 extending out of the two sides of the negative electrode tab 22 in the length direction of the negative electrode tab 21 may be equal or unequal.

Optionally, the winding core 20 further includes a positive plate 23 and a positive tab assembly, the positive plate 23 includes a positive current collector 231 and a positive active layer 232, and the positive active layer 232 is coated on two opposite sides of the positive current collector 231. For example, the positive electrode current collector 231 is usually made of aluminum foil, but other materials may be used for the positive electrode current collector 231 according to actual needs as long as the requirements of the winding core 20 can be met.

The winding head end of the positive current collector 231 is exposed to form a positive double-sided empty foil area 2311, wherein the winding head end refers to the end of the winding start; the positive electrode double-sided empty foil area 2311 refers to an area where neither of opposite sides of the positive electrode current collector 231 is covered with the positive electrode active layer 232. The positive tab assembly is arranged in the positive double-sided empty foil area 2311, a preset distance is reserved between the positive tab assembly and the negative tab 22, the negative tab 22 is located between the positive tab assembly and the bending area 21121, the positive tab assembly comprises a positive tab 24, the preset distance between the positive tab 24 and the negative tab 22 can be set according to actual needs, and specific limitation is not made here.

Optionally, the end of the winding head end of the positive current collector 231 extends to between the positive tab 24 and the negative tab 22, and the opposite sides of the portion, located between the positive tab 24 and the negative tab 22, of the positive current collector 231 are both provided with the protective adhesive paper layer 35, the protective adhesive paper layer 35 may be attached to the negative current collector 211 located on the opposite sides of the positive current collector 231, may also be attached to the positive current collector 231, and may also be attached to the separators located on the opposite sides of the positive current collector 231. A first end of the protection adhesive paper layer 35 may be connected to an end of the negative tab 22 facing the positive tab 24, and a second end of the protection adhesive paper layer 35 may be connected to an end of the positive tab 24 facing the negative tab 22; the protective adhesive paper layer 35 prevents the burrs on the positive electrode current collector 231 from piercing the diaphragm to cause the internal short circuit of the winding core 20, and is used for increasing the thickness of the winding core 20 between the positive electrode tab 24 and the negative electrode tab 22 so as to improve the unevenness of the surface of the winding core 20.

Optionally, the end of the winding tail end of the positive electrode collector 231 extends to between the positive electrode tab 24 and the negative electrode tab 22, and the winding tail end of the positive electrode collector 231 is provided with the sealing adhesive paper layer 36. The sealing adhesive paper layer 36 fixes the winding tail end of the positive electrode current collector 231 on the outer surface of the winding core 20 to ensure the stability and reliability of the winding core 20 after winding, and is used for increasing the thickness of the winding core 20 between the positive electrode tab 24 and the negative electrode tab 22 to improve the unevenness of the surface of the winding core 20.

The two opposite sides of the positive electrode double-sided empty foil area 2311 are provided with second adhesive paper layers 32, the first ends of the two second adhesive paper layers 32 are respectively lapped on the first ends of the positive electrode active layers 232 on the two opposite sides of the positive electrode current collector 231, and the second ends of the two second adhesive paper layers 32 are connected with one end, far away from the negative electrode tab 22, of the positive electrode tab assembly. On the one hand, since the starting end and the tail end of the positive electrode active layer 232 coated on the positive electrode current collector 231 are generally burred, the first end of the second adhesive paper layer 32 is overlapped at the first end of the positive electrode active layer 232, which is beneficial to preventing the bur at the first end of the positive electrode active layer 232 from piercing through the diaphragm between the positive electrode sheet 23 and the negative electrode sheet 21, and causing the internal short circuit of the winding core 20. On the other hand, the second end of the second adhesive paper layer 32 is connected with the end of the positive tab assembly far away from the negative tab 22, so that the thickness of the winding core 20 at the end of the positive tab assembly far away from the negative tab 22 is substantially consistent with the thickness of the region of the winding core 20 where the positive tab assembly is arranged; thereby being beneficial to improving the condition of the unevenness of the surface of the roll core 20.

In specific implementation, the thicknesses of the two second adhesive paper layers 32 can be equal or unequal according to actual needs; the two second adhesive paper layers 32 may also be arranged to have equal or unequal sizes in the length direction of the positive electrode sheet 23 according to actual needs. In an alternative implementation manner, two second adhesive paper layers 32 may be provided, and the size of the second adhesive paper layers in the length direction of the positive electrode sheet 23 is equal to the distance from the end of the positive electrode tab far away from the negative electrode tab to the first end of the positive electrode active layer.

Optionally, the positive tab assembly comprises a positive tab 24, a first positive tab adhesive paper layer 51 and a second positive tab adhesive 52 layer, wherein the first positive tab adhesive paper layer 51 covers the surface of the positive tab 24 to prevent burrs on the surface of the positive tab 24 from piercing the separator and causing internal short circuit of the winding core 20; the second positive electrode tab adhesive paper layer 52 covers the surface of the positive electrode tab 24 deviating from the positive electrode tab 2311 in the positive electrode double-sided empty foil area, and the position of the second positive electrode tab adhesive paper layer 52 is opposite to that of the first positive electrode tab adhesive paper layer 51, so that the situation that the formed welding burrs pierce through the diaphragm to cause the internal short circuit of the winding core 20 in the process of welding the positive electrode tab 24 in the positive electrode tab 24 deviating from the surface of the positive electrode tab 2311 is prevented.

The dimension of the first positive tab adhesive paper layer 51 in the longitudinal direction of the positive tab 23 may be greater than or equal to the dimension of the positive tab 24 in the longitudinal direction of the positive tab 23. The dimension of the second positive tab adhesive paper layer 52 in the length direction of the positive tab 23 may be greater than or equal to the dimension of the positive tab 24 in the length direction of the positive tab 23. Wherein, the size range of the positive tab 24 in the length direction of the positive sheet 23 can be 5mm to 10 mm; the thickness of the positive tab 24 may range from 45 μm to 110 μm; the size range of the first positive tab adhesive paper layer 51 and the second positive tab adhesive paper layer 52 in the length direction of the positive plate 23 can be 10mm to 20 mm; the thickness of the first and second positive tab adhesive paper layers 51 and 52 may range from 5 μm to 16 μm.

For example, when the size of the first positive tab adhesive paper layer 51 and the second positive tab adhesive paper layer 52 in the length direction of the positive tab 23 is larger than the size of the positive tab 24 in the length direction of the positive tab 23, the size of the first positive tab adhesive paper layer 51 extending out of the two sides of the positive tab 24 along the length direction of the positive tab 23 may be equal or unequal; the size of the second positive tab adhesive paper layer 52 extending out of the two sides of the positive tab 24 along the length direction of the positive tab 23 may be equal or unequal.

In an alternative implementation manner, the second ends of the two second adhesive paper layers 32 are respectively connected to the ends of the first tab adhesive paper layer 51 and the second tab adhesive paper layer 52, which are far away from the negative tab 22, so that the thickness of the winding core 20, which is located at the end of the positive tab 24, which is far away from the negative tab 22, is kept uniform, thereby facilitating improvement of the unevenness of the surface of the winding core 20.

In another alternative implementation, the second adhesive paper layer 32 and the second positive tab adhesive paper layer 52 on the side of the positive double-sided empty foil area 2311 away from the positive tab 24 may be an integral piece, so as to further keep the thickness of the winding core 20 at the end of the positive tab 24 away from the negative tab 22 uniform, and further improve the surface roughness of the winding core 20.

Similarly, the second adhesive paper layer 32 and the first positive tab adhesive paper layer 51 on the side of the positive tab 24 in the positive double-sided empty foil area 2311 can be an integrated piece, so that the thickness of the end, away from the negative tab 22, of the positive tab 24, which is in the position of the winding core 20, is kept uniform, and the surface unevenness of the winding core 20 is improved.

Optionally, two third adhesive paper layers 33 are disposed at the winding end of the positive plate 23, first ends of the two third adhesive paper layers 33 are respectively overlapped with second ends of the positive active layers 232 on two opposite surfaces of the positive current collector 231, and projections of the second ends of the two third adhesive paper layers 33 in the thickness direction of the winding core are connected with projections of one end, far away from the negative tab 22, of the positive tab 24 in the thickness direction of the winding core. On the one hand, since the starting end and the tail end of the positive electrode active layer 232 coated on the positive electrode current collector 231 are generally burred, the first end of the third adhesive paper layer 33 is overlapped at the second end of the positive electrode active layer 232, which is beneficial to preventing the bur at the second end of the positive electrode active layer 232 from piercing the diaphragm between the positive electrode sheet 23 and the negative electrode sheet 21, and causing the internal short circuit of the winding core 20. On the other hand, the projection of the second end of the third adhesive paper layer 33 along the thickness direction of the winding core is connected with the projection of the end of the positive tab 24 far away from the negative tab 22 along the thickness direction of the winding core, so as to further ensure that the thickness of the winding core 20 at the end of the positive tab 24 far away from the negative tab 22 is basically consistent with the thickness of the region of the winding core 20 where the positive tab 24 is arranged; thereby being beneficial to improving the condition of the unevenness of the surface of the roll core 20.

In specific implementation, the thicknesses of the two third adhesive paper layers 33 can be equal or unequal according to actual needs; the two third adhesive paper layers 33 may also be arranged to have equal or unequal sizes in the length direction of the positive electrode sheet 23 according to actual needs. In an alternative implementation, two third adhesive paper layers 33 may be provided with equal size along the length direction of the positive electrode sheet 23, for example, the size of the third adhesive paper layer in the length direction of the positive electrode sheet is equal to the roll core thickness × 3.14 ÷ 2+ roll core thickness ÷ 2+ horizontal distance + δ between the end of the positive electrode tab far away from the negative electrode tab and the first end of the positive electrode active layer, where δ is a tolerance, and δ is greater than or equal to 2mm and less than or equal to 3 mm.

Optionally, the sum of the thicknesses of the two second adhesive paper layers 32 and the thicknesses of the two third adhesive paper layers 33 is a first thickness value; the sum of the thickness of the positive tab 24, the thickness of the first positive tab adhesive paper layer 51 and the thickness of the second positive tab adhesive paper layer 52 is a second thickness value, and the difference between the first thickness value and the second thickness value ranges from 80% to 120%. For example, the first thickness value may be equal to the second thickness value, or the first thickness value may be less than the second thickness value, or the first thickness value may be greater than the second thickness value, as long as the difference between the first thickness value and the second thickness value is in the range of 80% to 120%. Therefore, the thickness of the winding core 20 at one end of the positive tab 24 far away from the negative tab 22 can be ensured to be consistent with the thickness of the region of the winding core 20 provided with the positive tab 24; thereby being beneficial to improving the uneven surface of the roll core 20.

The winding core 20 further includes a separator (not shown in the drawings) disposed between the positive electrode tab 21 and the negative electrode tab 23 to insulate the positive electrode tab 21 from the negative electrode tab 23. Optionally, the sum of the thickness of the positive tab 24, the thickness of the first positive tab adhesive paper layer 51, the thickness of the second positive tab adhesive paper layer 52, the double thickness of the positive current collector 231, and the double thickness of the separator is a third thickness value; twice the thickness of the first glue paper layer 31 is the fourth thickness value; the difference between the third thickness value and the fourth thickness value ranges from 80% to 120%, and the third thickness value may be equal to the fourth thickness value, or the third thickness value is smaller than the fourth thickness value, or the third thickness value is larger than the fourth thickness value, as long as the difference between the third thickness value and the fourth thickness value ranges from 80% to 120%. When the thickness of the positive tab 24 is equal to that of the negative tab 22, and the thickness of the negative tab adhesive paper layer 41 is equal to that of the first positive tab adhesive paper layer 51, the relationship can be further expressed as follows: the sum of the thickness of the negative electrode tab 22, the thickness of the negative electrode tab adhesive paper layer 41, the thickness of the second positive electrode tab adhesive paper layer 52, the twice thickness of the positive electrode current collector 231 and the twice thickness of the separator is equal to twice the thickness of the first adhesive paper layer 31. Therefore, the thickness of the winding core 20 at one end of the negative tab 22 far away from the positive tab 24 can be ensured to be consistent with the thickness of the winding core 20 in the area provided with the positive tab 24; thereby being beneficial to improving the uneven surface of the roll core 20.

Optionally, the negative tab 22 includes a negative tab welding section and a negative tab free section that are connected to each other, the negative tab welding section extends along the width direction of the negative plate 21 and is welded in the negative double-sided empty foil area 2111, and the negative tab free section extends out of the negative double-sided empty foil area 2111. The length of the negative electrode tab welding section is greater than or equal to the width of the negative electrode tab 21, so that the thickness of the winding core 20 in the width direction of the negative electrode tab 21 is kept uniform, and the surface unevenness of the winding core 20 is improved.

Further, a negative electrode tab rubber gasket 42 is arranged at one end of the free section of the negative electrode tab, which is close to the welding section of the negative electrode tab, and the negative electrode tab rubber gasket 42 can seal a gap between the negative electrode tab 22 and the casing when the winding core 20 is packaged in the casing. When the length of the negative electrode tab welding segment is greater than the width of the negative electrode tab 21, a portion of the negative electrode tab welding segment extending out of the negative electrode tab 21, that is, a portion of the length of the negative electrode tab welding segment different from the width of the negative electrode tab 21, may be located between the negative electrode tab 21 and the negative electrode tab rubber pad 42. On one hand, a hot-melting extension space of the negative tab rubber pad 42 is reserved, so that the negative tab rubber pad 42 is prevented from being melted and embedded between the positive plate 23 and the negative plate 21 during packaging; on the other hand, a bending adjustment space is reserved at one end of the negative electrode tab 22 close to the negative electrode sheet 21, so that the negative electrode tab rubber pad 42 is prevented from being directly attached to the end face formed by winding the positive electrode sheet 23 and the negative electrode sheet 21 when the position of the negative electrode tab 22 is adjusted by bending. Illustratively, the difference between the length of the negative tab welding section and the width of the negative tab 21 is between 0.5mm and 1.5mm, and in particular, the difference between the length of the negative tab welding section and the width of the negative tab 21 may be set to any value between 0.5mm, 0.7mm, 0.9mm, 1.1mm, 1.3mm, 1.5mm, or 0.5mm and 1.5mm according to actual needs.

Optionally, the positive tab 24 includes a positive tab welding section and a positive tab free section that are connected to each other, the positive tab welding section extends along the width direction of the positive tab 23 and is welded in the positive double-sided empty foil area 2311, and the positive tab free section extends out of the positive double-sided empty foil area 2311. The length of the positive tab welding section is greater than or equal to the width of the positive plate 23, so that the thickness of the winding core 20 in the width direction of the positive plate 21 is kept uniform, and the condition that the surface of the winding core 20 is uneven is favorably improved.

In general, the width of the positive electrode tab 23 is greater than the width of the negative electrode tab 21, and the difference between the width of the positive electrode tab 23 and the width of the negative electrode tab 21 ranges from 0.5mm to 2 mm. Illustratively, the difference between the width of the positive electrode tab 23 and the width of the negative electrode tab 21 may be set to 0.5mm, 1mm, 1.5mm, 2mm, or any value between 0.5mm and 2mm according to actual needs.

Further, the free section of the positive tab is provided with a positive tab cushion (not shown in the figure) at an end close to the welding section of the positive tab, and the positive tab cushion can seal a gap between the positive tab 24 and the housing when the winding core 20 is packaged in the housing. When the length of the positive tab welding section is greater than the width of the positive tab 23, the portion of the positive tab welding section extending out of the positive tab 23, that is, the portion of the length of the positive tab welding section different from the width of the positive tab 23, may be located between the positive tab 23 and the positive tab rubber mat. On one hand, a hot-melting extension space of the anode tab rubber pad is reserved, so that the anode tab rubber pad is prevented from being melted and embedded between the anode plate 23 and the cathode plate 21 during packaging; on the other hand, a bending adjustment space is reserved at one end of the positive tab 24 close to the positive plate 23, so that the situation that the positive tab rubber pad is directly attached to the end face formed by winding the positive plate 23 and the negative plate 21 when the position of the positive tab 24 is adjusted in a bending mode is avoided. Illustratively, the difference between the length of the positive tab welding section and the width of the positive tab 23 is between 0.5mm and 1.5mm, and in particular, the difference between the length of the positive tab welding section and the width of the positive tab 23 can be set to any value between 0.5mm, 0.7mm, 0.9mm, 1.1mm, 1.3mm, 1.5mm, or 0.5mm and 1.5mm according to actual needs.

Optionally, the winding core further includes a fourth adhesive paper layer 34, the fourth adhesive paper layer 34 is attached to at least one side of the outer surface of the winding core, and the fourth adhesive paper layer 34 is located between the negative electrode tab 22 and the positive electrode tab 24. Specifically, the fourth adhesive paper layer 34 may be attached to any side of the outer surface of the winding core, or the fourth adhesive paper layer 34 may be attached to the opposite side of the outer surface of the winding core. For example, the fourth adhesive paper layer 34 may be wrapped around the outer surface of the winding core, or may be attached to only two opposite surfaces of the winding core. On the one hand, the fourth adhesive paper layer 34 can make the thickness of the part of the winding core between the negative electrode tab 22 and the positive electrode tab 24 basically consistent with the thickness of the part of the winding core provided with the negative electrode tab 22 and the positive electrode tab 24, thereby being beneficial to improving the flatness of the winding core, improving the interface bonding effect of the winding core after formation, and finally achieving the purposes of improving the long cycle life, the expansion problem and the deformation problem of the battery. On the other hand, the fourth adhesive paper layer 34 can play a role of buffering when the winding core falls or is impacted, thereby being beneficial to improving the falling performance of the winding core.

Optionally, the width of the fourth adhesive paper layer 34 is less than or equal to the width between the negative tab 22 and the positive tab 24, so as to ensure that the fourth adhesive paper layer 34 is disposed between the negative tab 22 and the positive tab 24, thereby facilitating improvement of the flatness of the winding core.

Optionally, twice the thickness of the fourth adhesive paper layer 34 is equal to the thickness of the negative tab 22, or twice the thickness of the fourth adhesive paper layer 34 is equal to the thickness of the positive tab 24, and the fourth adhesive paper layer 34 can increase the thickness of the part of the winding core between the negative tab 22 and the positive tab 24, so that the thickness of the part of the winding core between the negative tab 22 and the positive tab 24 is substantially the same as the thickness of the part of the winding core provided with the negative tab 22 and the positive tab 24, thereby being beneficial to improving the flatness of the winding core. The thickness of the negative tab 22 may be equal to the thickness of the positive tab 24.

Example two

On the basis of embodiment one, this embodiment provides a laminate polymer battery, and this laminate polymer battery includes shell and book core, and it encapsulates in the shell to roll up the core. Illustratively, the housing may be an aluminum plastic film housing.

The winding core provided by the present embodiment has the same structure as the winding core in the first embodiment, and can bring the same or similar technical effects, specifically referring to the first embodiment.

The laminate polymer battery that this embodiment provided includes shell and book core, rolls up the core encapsulation in the shell. Under the condition that the unevenness on the surface of the roll core is improved, the flatness of the soft package battery is also improved, so that the interface bonding effect of the soft package battery after formation is improved, and the purposes of improving the long cycle life, the expansion problem and the deformation problem of the soft package battery are finally achieved.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection or a removable connection; can be mutually contacted or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, or through the communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The terms "first" and "second" in the description and claims of the present application and the description of the above-described figures are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims (11)

1. The utility model provides a roll up core, its characterized in that includes the negative pole piece, the internal surface that the second bending zone of negative pole piece along the direction of convoluteing has covered first adhesive paper layer, the both ends of first adhesive paper layer are followed the projection of the thickness direction of rolling up the core, with the head end edge of convoluteing of negative pole piece the projection of the thickness direction of rolling up the core meets or partial coincidence.

2. The winding core according to claim 1, further comprising a negative tab, wherein the negative tab comprises a negative current collector and a negative active layer coated on opposite sides of the negative current collector; the winding head end of the negative current collector is exposed in sequence along the winding direction to form a negative double-sided empty foil area and a negative single-sided empty foil area, and the negative tab is arranged in the negative double-sided empty foil area;

the first adhesive paper layer is located in the negative single-face empty foil area, and the projections of the two ends of the first adhesive paper layer in the thickness direction of the winding core are connected with the projections of the ends, close to the bending areas, of the negative electrode lugs in the thickness direction of the winding core.

3. The winding core according to claim 2, characterized in that the side of the first adhesive paper layer facing away from the negative single-sided free foil area is provided with a recess.

4. The winding core according to claim 3, wherein the thickness of the central region of the depression in the longitudinal direction of the negative electrode sheet is smaller than the thickness of the other regions of the depression; and the thickness of the depressed part gradually increases from the middle area of the depressed part to both sides.

5. The winding core according to claim 4, characterized in that the thickness of the central region of the depression ranges from 3 μm to 8 μm; and/or the presence of a gas in the gas,

the size range of the opening of the depressed part in the length direction of the negative plate is 1mm to 5 mm; and/or the presence of a gas in the gas,

the middle area of the depressed part corresponds to the middle area of the negative single-sided empty foil area in the length direction of the negative plate.

6. The winding core according to claim 2, further comprising a positive plate and a positive tab assembly, wherein the positive plate comprises a positive current collector and a positive active layer, and the positive active layer is coated on two opposite surfaces of the positive current collector; the winding head end of the positive current collector is exposed to form a positive double-sided empty foil area, the positive tab assembly is arranged in the positive double-sided empty foil area and has a preset distance with the negative tab, and the negative tab is positioned between the positive tab assembly and the bending area;

the two opposite sides in positive pole two-sided empty paper tinsel district all are provided with second adhesive paper layer, two the first end on second adhesive paper layer overlaps respectively and is lieing in the two opposite sides of anodal mass flow body the first end on positive pole active layer, two the second end on second adhesive paper layer all with keeping away from of anodal ear subassembly the one end of negative pole ear meets.

7. The winding core according to claim 6, wherein the positive tab assembly comprises a positive tab, a first positive tab adhesive paper layer and a second positive tab adhesive paper layer, the first positive tab adhesive paper layer covers the surface of the positive tab, the second positive tab adhesive paper layer covers the surface of the positive double-sided empty foil area, which is away from the positive tab, and the second positive tab adhesive paper layer is opposite to the first positive tab adhesive paper layer;

the second ends of the two second adhesive paper layers are respectively connected with one ends, far away from the negative electrode tab, of the first positive electrode tab adhesive paper layer and the second positive electrode tab adhesive paper layer; and/or the presence of a gas in the gas,

the second adhesive paper layer and the second positive tab adhesive paper layer which are positioned on the surface, deviating from the positive tab, of the positive double-sided empty foil area are integrated; and/or the presence of a gas in the gas,

and the second adhesive paper layer positioned on one surface of the positive lug in the positive double-sided empty foil area and the first adhesive paper layer of the positive lug are integrated.

8. The winding core according to claim 7, wherein two third adhesive paper layers are arranged at the winding tail end of the positive plate, the first ends of the two third adhesive paper layers are respectively lapped at the second ends of the positive active layers on the two opposite surfaces of the positive current collector, and the projections of the second ends of the two third adhesive paper layers along the thickness direction of the winding core are connected with the projections of the ends, far away from the negative electrode lugs, of the positive electrode lugs along the thickness direction of the winding core.

9. The winding core according to claim 8, characterized in that the sum of the thicknesses of the two second plies and of the two third plies is a first thickness value; the sum of the thickness of the positive tab, the thickness of the first positive tab adhesive paper layer and the thickness of the second positive tab adhesive paper layer is a second thickness value;

the difference between the first thickness value and the second thickness value ranges between 80% and 120%.

10. The winding core according to claim 7, further comprising a separator disposed between the positive electrode tab and the negative electrode tab;

the sum of the thickness of the positive tab, the thickness of the first positive tab adhesive paper layer, the thickness of the second positive tab adhesive paper layer, the two times of the thickness of the positive current collector and the two times of the thickness of the diaphragm is a third thickness value; twice the thickness of the first ply is a fourth thickness value;

the difference between the third thickness value and the fourth thickness value ranges between 80% and 120%;

and/or, still include the fourth adhesive paper layer, the fourth adhesive paper layer subsides are established at least one side of the surface of rolling up the core, just the fourth adhesive paper layer is located the negative pole ear with between the positive pole ear.

11. A pouch cell comprising a can and the winding core of any of claims 1-10, the winding core being enclosed in the can.

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