Battery cell and electric equipment

Abstract

The invention provides a battery cell and electric equipment. The battery cell comprises an electrode assembly, and the electrode assembly is formed by winding a first pole piece, a diaphragm and a second pole piece which are arranged in a stacked mode; the first surface of the first pole piece is provided with the bulge, so that after the electrode assembly is wound, the bulge is propped against the diaphragm, and the distance between the first surface and the diaphragm is larger in the thickness direction of the first pole piece, so that a larger infiltration space is formed between the first pole piece and the diaphragm, and the storage and infiltration of electrolyte are conveniently increased; the possibility of metal ion precipitation generated by long circulation of the battery cell can be reduced, so that the service life of the battery cell can be prolonged; in addition, the average thickness of the bulges arranged on the circle of the first pole piece is gradually increased from the winding center of the electrode assembly to the outside, so that the storage and infiltration of the electrolyte on the electrode assembly can be further improved, the possibility of metal ion precipitation generated by long circulation of the battery cell can be further reduced, and the service life of the battery cell is further prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery cell and a power consumption device. BACKGROUND

[0002] With the rapid development of electronic information technology, various electronic devices are also developing towards intelligence and multifunction, and the service life of the battery is also becoming increasingly demanding. Therefore, how to improve the service life of the battery has become a problem to be solved in the battery field. SUMMARY

[0003] The present application provides a battery cell and a power consumption device, which can effectively prolong the service life of the battery cell.

[0004] In a first aspect, the present application provides a battery cell, which comprises an electrode assembly, and the electrode assembly is wound by a first electrode sheet, a separator and a second electrode sheet arranged in layers. The first electrode sheet has a first surface, the first surface is perpendicular to the thickness direction of the first electrode sheet, and the first surface is provided with a protrusion. From the winding center of the electrode assembly outward, the average thickness of the protrusion on one circle of the first electrode sheet gradually increases.

[0005] By arranging the protrusion on the first surface of the first electrode sheet, the protrusion can abut against the separator after the electrode assembly is wound, the distance between the first surface and the separator in the thickness direction of the first electrode sheet is larger, so that a larger soaking space is formed between the first electrode sheet and the separator, which facilitates the storage and soaking of the electrolyte, can reduce the possibility of metal ion precipitation caused by long cycle of the battery cell, thereby prolonging the service life of the battery cell and being beneficial to improve the capacity and energy density of the battery cell. Since the longer the length of the part of the first electrode sheet located in the outer circle is, the more difficult the electrolyte is to soak, by gradually increasing the average thickness of the protrusion on one circle of the first electrode sheet from the winding center of the electrode assembly outward, the storage and soaking of the electrolyte in the electrode assembly can be further improved, thereby further reducing the possibility of metal ion precipitation caused by long cycle of the battery cell, and further prolonging the service life of the battery cell.

[0006] In some embodiments of the present application, the thickness of the protrusion on one circle of the first electrode sheet closest to the winding center of the electrode assembly is H0 μm, the first electrode sheet comprises a first current collector and a first active material layer, the first active material layer is arranged on at least one side surface of the first current collector in the thickness direction thereof, the thickness of the first active material layer is T1 μm, and 0.1×T1≤H0≤0.5×T1.

[0007] In the technical solution, when H0 is greater than or equal to 0.1*T1, the thickness of the protrusion is large, the space between the first electrode sheet and the diaphragm is large after the electrode assembly is wound, the electrolyte is easy to infiltrate and store, and the possibility of metal ion precipitation in long cycle of the battery cell is reduced; when H0 is less than or equal to 0.5*T1, the thickness of the electrode assembly is small, the energy density of the battery cell is high, and when the protrusion is prepared by rolling, the pressure applied to the first electrode sheet is small, the first electrode sheet is not easy to be damaged, and the preparation of the electrode assembly is facilitated. Therefore, when H0 is 0.1*T1-0.5*T1, the electrolyte is easy to infiltrate and store, the possibility of metal ion precipitation in long cycle of the battery cell is reduced, the thickness of the electrode assembly is small, the energy density of the battery cell is high, and when the protrusion is prepared by rolling, the pressure applied to the first electrode sheet is small, the first electrode sheet is not easy to be damaged, and the preparation of the electrode assembly is facilitated.

[0008] In some embodiments of the present application, the second electrode sheet comprises a second current collector and a second active material layer, and the second active material layer is arranged on at least one side surface of the second current collector in the thickness direction. The average thickness of the protrusion of the first electrode sheet at the Nth winding turn is H μm, H≥H0+β*N*T2, H0≥β*T2, wherein H0 is the average thickness of the protrusion on the winding turn closest to the winding center of the electrode assembly, β is the expansion rate of the battery cell, β=(thickness of the battery cell in the full charge state-thickness of the battery cell in the empty charge state) / thickness of the battery cell in the empty charge state, T2=(thickness of the second electrode sheet in the empty charge state-thickness of the second current collector) / 2, and N is the winding number of the first electrode sheet, wherein the units of H0 and T2 are μm.

[0009] In the technical solution, the average thickness H of the protrusion of the first electrode sheet at the Nth winding turn is positively correlated with the winding number N of the first electrode sheet and the expansion rate of the battery cell, that is, the greater the winding number N of the first electrode sheet, the greater the average thickness H of the protrusion of the first electrode sheet at the Nth winding turn, the greater the expansion rate of the battery cell, and the greater the average thickness H of the protrusion of the first electrode sheet at the Nth winding turn, so that the protrusion can be set to a corresponding thickness according to different models of battery cells, a more reasonable infiltration space can be formed between the first electrode sheet and the diaphragm, the storage and infiltration of the electrolyte are facilitated, and the capacity and energy density of the battery cell are improved.

[0010] In some embodiments of the present application, the first electrode sheet, the diaphragm, and the second electrode sheet are wound and form two flat regions and two bending regions, each bending region connects two ends of two flat regions, and the protrusion is arranged in the bending region.

[0011] In the technical solution, the bending area of the electrode assembly is more difficult to be infiltrated by the electrolyte than the flat area, and the possibility of metal ion precipitation is more likely to occur. The protrusions arranged on the bending area can facilitate the infiltration and storage of the electrolyte in the bending area, reduce the possibility of metal ion precipitation caused by long cycle of the battery cell, prolong the service life of the battery cell, and improve the capacity and energy density of the battery cell.

[0012] In some embodiments of the present application, each bending area includes a plurality of bending segments, and a plurality of protrusions are arranged on each bending segment. The thickness of the plurality of protrusions on each bending segment is equal.

[0013] In the technical solution, the thickness of the plurality of protrusions on each bending segment is equal, which can facilitate the preparation of the protrusions and improve the preparation efficiency of the first electrode sheet. In the formation process, the difference in expansion rate of each part of the bending segment is small, the difference in spacing distance between each part of the bending segment and the separator is small, and the thickness of the plurality of protrusions on each bending segment is equal, which can make the spacing distance between each bending segment and the separator uniform, further facilitate the infiltration and storage of the electrolyte in the bending area, further reduce the possibility of metal ion precipitation caused by long cycle of the battery cell, further prolong the service life of the battery cell, and further improve the capacity and energy density of the battery cell.

[0014] In some embodiments of the present application, the projection area of the protrusions arranged on a circle of the first electrode sheet gradually increases outward from the winding center of the electrode assembly along the thickness direction of the first electrode sheet.

[0015] In the technical solution, the expansion pressure gradually increases for each circle of the first electrode sheet outward from the winding center of the electrode assembly, which can make the spacing distance between each circle of the first electrode sheet and the separator gradually decrease outward from the winding center of the electrode assembly. Therefore, the projection area of the protrusions arranged on a circle of the first electrode sheet gradually increases outward from the winding center of the electrode assembly along the thickness direction of the first electrode sheet, which can make the support force of the protrusions arranged on a circle of the first electrode sheet gradually increase outward from the winding center of the electrode assembly, thereby making the spacing distance between the first electrode sheet and the separator more uniform, further facilitating the infiltration and storage of the electrolyte between the first electrode sheet and the separator, further reducing the possibility of metal ion precipitation caused by long cycle of the battery cell, further prolonging the service life of the battery cell, and further improving the capacity and energy density of the battery cell.

[0016] In some embodiments of the present application, the number of protrusions arranged on a circle of the first electrode sheet gradually increases outward from the winding center of the electrode assembly.

[0017] In the technical solution, the expansion pressure gradually increases from the winding center of the electrode assembly to the outside, which causes the distance between the first electrode plate and the diaphragm gradually to decrease from the winding center of the electrode assembly to the outside. Therefore, by gradually increasing the number of protrusions on the first electrode plate from the winding center of the electrode assembly to the outside, the support force of the protrusions on the first electrode plate gradually increases from the winding center of the electrode assembly to the outside, so that the distance between the first electrode plate and the diaphragm is more uniform, thereby further facilitating the infiltration and storage of the electrolyte between the first electrode plate and the diaphragm, further reducing the possibility of metal ion precipitation caused by long cycle of the battery cell, further prolonging the service life of the battery cell, and further improving the capacity and energy density of the battery cell.

[0018] In some embodiments of the present application, the first surface is away from the winding center of the electrode assembly.

[0019] In the technical solution, by making the first surface away from the winding center of the electrode assembly, the possibility of mutual extrusion of the protrusions during winding of the electrode assembly, which causes the distance between the protrusions to be too small to achieve infiltration and storage of the electrolyte, can be reduced, so that the infiltration and storage effect of the electrolyte in the electrode assembly is better.

[0020] In some embodiments of the present application, the protrusion has a cylindrical structure, and the surface of the protrusion is arc-shaped.

[0021] In the technical solution, by making the protrusion have a cylindrical structure, the preparation of the protrusion is facilitated, and by making the surface of the protrusion arc-shaped, the possibility of damage to the diaphragm caused by interference between the protrusion and the diaphragm is reduced, which is beneficial to reducing the possibility of short circuit of the battery cell, thereby improving the safety of the battery cell.

[0022] In some embodiments of the present application, a plurality of protrusions are arranged on the one circle of the first electrode plate, and the plurality of protrusions are arranged in an array.

[0023] In the technical solution, by arranging a plurality of protrusions on the one circle of the first electrode plate, the plurality of parts of the first electrode plate are spaced from the diaphragm by the protrusions, thereby facilitating the infiltration and storage of the electrolyte between the plurality of parts of the first electrode plate and the diaphragm, and improving the infiltration speed of the electrolyte; by arranging the plurality of protrusions in an array, the protrusions are uniformly distributed, so that the part of the first electrode plate provided with the plurality of protrusions is completely spaced from the diaphragm, further facilitating the infiltration and storage of the electrolyte between the part of the first electrode plate provided with the protrusions and the diaphragm, and further improving the infiltration speed of the electrolyte.

[0024] In some embodiments of the present application, the first tab includes a first current collector and two layers of first active material layers, the two layers of first active material layers are respectively arranged on two side surfaces of the first current collector along the thickness direction of the first current collector, and the protrusion is integrally formed on the first active material layer.

[0025] In the above technical solution, by integrally forming the protrusion on the first active material layer, the preparation of the protrusion can be facilitated, and the possibility of the protrusion being stressed and separated from the first tab can be reduced.

[0026] In some embodiments of the present application, the first tab is a positive tab, and the second tab is a negative tab.

[0027] In a second aspect, the present application provides a power-using device, including the battery cell as described above, and the battery cell is used to provide electric energy. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows, and it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and other related drawings can also be obtained by those skilled in the art according to these drawings.

[0029] Figure 1 A cross-sectional structural schematic diagram of an electrode assembly of a battery cell provided for some embodiments of the present application;

[0030] Figure 2 A structural schematic diagram of a first tab of a battery cell in an unfolded state provided for some embodiments of the present application;

[0031] Figure 3 A schematic diagram of part of the structure of the first tab of the battery cell in a wound state provided for some embodiments of the present application;

[0032] Figure 4 A structural schematic diagram of a first tab of a battery cell in an unfolded state provided for some other embodiments of the present application;

[0033] Figure 5 A structural schematic diagram of a first tab of a battery cell in an unfolded state from another perspective provided for some embodiments of the present application;

[0034] Figure 6 A structural schematic diagram of a first tab of a battery cell in an unfolded state provided for some embodiments of the present application.

[0035] Icon: 100 - electrode assembly; 101 - flat area; 102 - bent area; 1021 - bent section; 110 - first tab; 111 - first current collector; 112 - first active material layer; 113 - positive electrode tab; 1121 - first surface; 1122 - protrusion; 120 - separator; 130 - second tab; 131 - second current collector; 132 - second active material layer; 133 - negative electrode tab; 1321 - second surface; 1322 - second protrusion; X - thickness direction of the first tab; Y - first direction; Z - second direction. DETAILED DESCRIPTION

[0036] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present application.

[0037] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0038] The terms "first", "second", etc. in the specification and claims of the present application or in the above description of drawings are used to distinguish different objects, rather than to describe a specific order or primary and secondary relationship.

[0039] In the present application, "embodiment" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments.

[0040] In the embodiments of the present application, the same reference signs represent the same components, and for brevity, detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device, are only exemplary and should not constitute any limitation on the present application.

[0041] With the development of new energy industry, batteries gradually develop towards high energy density and high power density. However, if the distance between the pole piece and the separator in the battery is too small, the electrolyte soaked between the pole piece and the separator will be insufficient, which will easily cause the problem of metal ion precipitation during the charging and discharging process of the battery, especially in the bending area of the winding type battery, the electrolyte is more difficult to soak, and the problem of metal ion precipitation is more likely to occur, which will cause the capacity of the battery to decrease and the service life to shorten.

[0042] In order to improve the service life of the electrochemical device, the application provides a battery, which comprises an electrode assembly. The electrode assembly is wound by a first pole piece, a separator and a second pole piece arranged in layers. The first pole piece has a first surface perpendicular to the thickness direction of the first pole piece, and the first surface is provided with a protrusion. The average thickness of the protrusion on the first pole piece gradually increases outward from the winding center of the electrode assembly.

[0043] In the battery with such a structure, the battery comprises an electrode assembly wound by a first pole piece, a separator and a second pole piece arranged in layers, so that the energy density of the battery is high. By providing the first pole piece with a first surface perpendicular to the thickness direction of the first pole piece, and the first surface is provided with a protrusion, the protrusion can abut against the separator after the electrode assembly is wound, the distance between the first surface and the separator in the thickness direction of the first pole piece is larger, so that a larger soaking space is formed between the first pole piece and the separator, which facilitates the storage and soaking of the electrolyte, reduces the possibility of metal ion precipitation during long cycle of the battery, thereby prolonging the service life of the battery and improving the capacity and energy density of the battery. Since the longer the length of the part of the first pole piece located in the outer circle, the more difficult the electrolyte is to soak, by gradually increasing the average thickness of the protrusion on the first pole piece outward from the winding center of the electrode assembly, the storage and soaking of the electrolyte in the electrode assembly can be further improved, thereby further reducing the possibility of metal ion precipitation during long cycle of the battery, and further prolonging the service life of the battery.

[0044] The battery provided by the embodiments of the application can be a secondary battery or a primary battery, for example, a lithium ion battery, a sodium ion battery or a magnesium ion battery, etc. The embodiments of the application are not limited in this regard. The electrochemical device can be in the shape of a cylinder, a flat body, a cuboid or other shapes, etc. The embodiments of the application are also not limited in this regard.

[0045] The embodiments of the application provide a power consumption device using the battery as a power source. The power consumption device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric car, an electric vehicle, a ship, a spacecraft, etc.

[0046] Referring to Figures 1 to 3 ,Figure 1 A cross-sectional structural schematic diagram of an electrode assembly of an electric core provided for some embodiments of the present application; Figure 2 A structural schematic diagram of a first tab of an electric core in an unfolded state provided for some embodiments of the present application; Figure 3 A structural schematic diagram of a first tab of an electric core in a partially wound state provided for some embodiments of the present application.

[0047] An electric core is provided in embodiments of the present application, which includes an electrode assembly 100 wound by a first tab 110, a separator 120 and a second tab 130 arranged in layers.

[0048] In some embodiments, the first tab 110 has a first surface 1121 perpendicular to a thickness direction X of the first tab, and the first surface 1121 is provided with a protrusion 1122.

[0049] By providing the protrusion 1122 on the first surface 1121 of the first tab 110, the protrusion 1122 can abut against the separator 120 after the electrode assembly 100 is wound, and the distance between the first surface 1121 and the separator 120 in the thickness direction X of the first tab is larger, so that a larger impregnation space is formed between the first tab 110 and the separator 120, which facilitates the storage and impregnation of electrolyte, can reduce the possibility of metal ion precipitation generated by long cycle of the electric core, thereby prolonging the service life of the electric core, and is beneficial to improve the capacity and energy density of the electric core.

[0050] In some embodiments, the average thickness of the protrusion 1122 provided on one circle of the first tab 110 gradually increases outward from the winding center of the electrode assembly 100.

[0051] Since the length of the part of the first tab 110 located in the outer circle is longer and the electrolyte is more difficult to impregnate outward from the winding center of the electrode assembly 100, by gradually increasing the average thickness of the protrusion 1122 provided on one circle of the first tab 110 outward from the winding center of the electrode assembly 100, the storage and impregnation of electrolyte in the electrode assembly 100 can be further improved, thereby further reducing the possibility of metal ion precipitation generated by long cycle of the electric core, further prolonging the service life of the electric core.

[0052] If one protrusion 1122 is provided on one circle of the first tab 110, the average thickness of the protrusion 1122 refers to the thickness of the single protrusion 1122. If multiple protrusions 1122 are provided on one circle of the first tab 110, the average thickness of the protrusions 1122 refers to the ratio of the total thickness of the multiple protrusions 1122 to the number of the protrusions 1122.

[0053] In some embodiments, the first tab 110 can be provided with the protrusions 1122 on each of the turns, which can further improve the storage and infiltration of the electrolyte in the electrode assembly 100, thereby further reducing the possibility of metal ion precipitation caused by long cycle of the battery cell and further prolonging the service life of the battery cell.

[0054] In other embodiments, the first tab 110 can be provided with the protrusions 1122 on some of the turns, for example, the protrusions 1122 are provided on the odd turns of the first tab 110, and the even turns are not provided with the protrusions.

[0055] In some embodiments, the thickness of the protrusions 1122 on the turn of the first tab 110 closest to the winding center of the electrode assembly is H0μm, the first tab 110 includes a first current collector 111 and a first active material layer 112, the first active material layer 112 is arranged on at least one side surface of the first current collector 111 along the thickness direction thereof, the thickness of the first active material layer 112 is T1μm, and 0.1×T1≤H0≤0.5×T1. For example, H0may be 0.1×T1, 0.3×T1or 0.5×T1, etc. Wherein, T1is the thickness of the single-layer first active material layer 112.

[0056] When H0is greater than or equal to 0.1×T1, the thickness of the protrusions 1122 can be larger, and after the electrode assembly 100 is wound, the spacing between the first tab 110 and the separator 120 is larger, which is beneficial for the infiltration and storage of the electrolyte and can reduce the possibility of metal ion precipitation caused by long cycle of the battery cell; when H0is less than or equal to 0.5×T1, the thickness of the electrode assembly 100 can be smaller, the energy density of the battery cell can be higher, and when the protrusions 1122 are prepared by rolling, the pressure applied to the first tab 110 can be smaller, which is not easy to damage and is beneficial for the preparation of the electrode assembly 100. Therefore, when H0is 0.1×T1-0.5×T1, the electrolyte can be infiltrated and stored, the possibility of metal ion precipitation caused by long cycle of the battery cell can be reduced, the thickness of the electrode assembly 100 can be smaller, the energy density of the battery cell can be higher, and when the protrusions 1122 are prepared by rolling, the pressure applied to the first tab 110 can be smaller, which is not easy to damage and is beneficial for the preparation of the electrode assembly 100.

[0057] In some embodiments, the second tab 130 includes a second current collector 131 and a second active material layer 132, and the second active material layer 132 is arranged on at least one side surface of the second current collector 131 along the thickness direction of the second current collector 131. The average thickness of the protrusion 1122 of the first tab at the Nth winding turn is H μm, H ≥ H0+ β × N × T2, H0≥ β × T2, wherein H0is the average thickness of the protrusion 1122 of the first tab 110 at a winding turn closest to the winding center of the electrode assembly 100, β is the expansion rate of the battery cell, β = (the thickness of the battery cell in the full charge state - the thickness of the battery cell in the empty charge state) / the thickness of the battery cell in the empty charge state, T2= (the thickness of the second tab in the empty charge state - the thickness of the second current collector) / 2, and N is the winding turn number of the first tab, wherein the units of H0and T2are μm.

[0058] By making the average thickness H of the protrusion 1122 of the first tab 110 at the Nth winding turn positively correlated with the winding turn number N of the first tab 110 and the expansion rate of the battery cell, that is, the greater the winding turn number N of the first tab 110, the greater the average thickness H of the protrusion 1122 of the first tab 110 at the Nth winding turn, the greater the expansion rate of the battery cell, and the greater the average thickness H of the protrusion 1122 of the first tab 110 at the Nth winding turn, the protrusion 1122 can be set to a corresponding thickness according to different models of battery cells, and a more reasonable wetting space can be formed between the first tab 110 and the separator 120, which facilitates the storage and wetting of the electrolyte and helps to improve the capacity and energy density of the battery cell.

[0059] In some embodiments, β is the expansion rate of the battery cell before it leaves the factory, that is, the expansion rate of the battery cell after the formation cycle. The thickness of the battery cell in the full charge state is greater than the thickness of the battery cell in the empty charge state. In the calculation formula of T2, the thickness of the second tab in the empty charge state is the thickness of the second tab in the empty charge state before the battery cell leaves the factory, that is, after the formation cycle.

[0060] In some embodiments, the first tab 110, the separator 120, and the second tab 130 are wound and formed into two flat regions 101 and two bending regions 102, and each bending region 102 connects two ends of the two flat regions 101, respectively.

[0061] In some embodiments, the cross section of the electrode assembly 100 in the thickness direction X of the first tab is a racetrack shape to form two flat regions 101 and two bending regions 102.

[0062] In other embodiments, the cross section of the electrode assembly 100 in the thickness direction of the first tab 110 can also be elliptical, circular, etc.

[0063] In some embodiments, the protrusion 1122 is arranged in the bending region 102.

[0064] Due to the bending area 102 of the electrode assembly 100, compared with the flat area 101, the electrolyte is more difficult to infiltrate, and the possibility of metal ion precipitation is more likely to occur. By arranging the protrusions 1122 on the bending area 102, the infiltration and storage of the electrolyte in the bending area 102 can be facilitated, the possibility of metal ion precipitation caused by long cycle of the battery can be reduced, thereby the service life of the battery can be prolonged, and the capacity and energy density of the battery can be improved.

[0065] In some embodiments, the flat area 101 can also be provided with protrusions 1122. By arranging the protrusions 1122 on the flat area 101, the infiltration and storage of the electrolyte in the flat area 101 can be facilitated, the possibility of metal ion precipitation caused by long cycle of the battery can be reduced, thereby the service life of the battery can be prolonged, and the capacity and energy density of the battery can be improved.

[0066] In some embodiments, each bending area 102 includes a plurality of bending segments 1021, and a plurality of protrusions 1122 are arranged on each bending segment 1021. The thicknesses of the plurality of protrusions 1122 on each bending segment 1021 are equal.

[0067] In some embodiments, the plurality of bending segments 1021 are stacked from the center of the winding of the electrode assembly outward.

[0068] By equalizing the thicknesses of the plurality of protrusions 1122 on each bending segment 1021, the preparation of the protrusions 1122 can be facilitated, and the preparation efficiency of the first electrode sheet 110 can be improved. In the formation process, the difference in expansion rate of each part of the bending segment 1021 is small, the difference in spacing distance between each part of the bending segment 1021 and the separator 120 is small, and the thicknesses of the plurality of protrusions 1122 on each bending segment 1021 are equal, so that the spacing distance between each bending segment 1021 and the separator 120 is uniform, which is more conducive to the infiltration and storage of the electrolyte in the bending area 102, and can further reduce the possibility of metal ion precipitation caused by long cycle of the battery, thereby further prolonging the service life of the battery, and further improving the capacity and energy density of the battery.

[0069] In some embodiments, from the center of the winding of the electrode assembly 100 outward, along the thickness direction X of the first electrode sheet, the projection area of the protrusions 1122 arranged on one circle of the first electrode sheet 110 gradually increases.

[0070] The expansion pressure gradually increases from the winding center of the electrode assembly 100 to the outside, which causes the distance between each coil of the first electrode tab 110 and the separator 120 to gradually decrease from the winding center of the electrode assembly 100 to the outside. Therefore, by gradually increasing the number of the protrusions 1122 on each coil of the first electrode tab 110 from the winding center of the electrode assembly 100 to the outside, the support force of the protrusions 1122 on each coil of the first electrode tab 110 gradually increases from the winding center of the electrode assembly 100 to the outside, which can make the distance between the first electrode tab 110 and the separator 120 more uniform, further facilitate the infiltration and storage of the electrolyte between the first electrode tab 110 and the separator 120, further reduce the possibility of metal ion precipitation caused by long cycle of the battery cell, further prolong the service life of the battery cell, and be beneficial to further improve the capacity and energy density of the battery cell.

[0071] In some embodiments, the number of the protrusions 1122 on each coil of the first electrode tab 110 gradually increases from the winding center of the electrode assembly 100 to the outside.

[0072] The expansion pressure gradually increases from the winding center of the electrode assembly 100 to the outside, which causes the distance between each coil of the first electrode tab 110 and the separator 120 to gradually decrease from the winding center of the electrode assembly 100 to the outside. Therefore, by gradually increasing the number of the protrusions 1122 on each coil of the first electrode tab 110 from the winding center of the electrode assembly 100 to the outside, the support force of the protrusions 1122 on each coil of the first electrode tab 110 gradually increases from the winding center of the electrode assembly 100 to the outside, which can make the distance between the first electrode tab 110 and the separator 120 more uniform, further facilitate the infiltration and storage of the electrolyte between the first electrode tab 110 and the separator 120, further reduce the possibility of metal ion precipitation caused by long cycle of the battery cell, further prolong the service life of the battery cell, and be beneficial to further improve the capacity and energy density of the battery cell.

[0073] In some embodiments, the first surface 1121 faces away from the winding center of the electrode assembly 100.

[0074] By making the first surface 1121 face away from the winding center of the electrode assembly 100, the possibility that the protrusions 1122 are pressed against each other during the winding of the electrode assembly 100 and the distance between the protrusions 1122 is too small to achieve the infiltration and storage of the electrolyte can be reduced, which can make the infiltration and storage of the electrolyte in the electrode assembly 100 better.

[0075] In some embodiments, the first surface 1121 can also include a surface of a side of the first tab 110 facing the winding center of the electrode assembly 100 and a surface of a side of the first tab 110 facing away from the winding center of the electrode assembly 100, and the interval between the plurality of protrusions 1122 on the surface of the side of the first tab 110 facing the winding center of the electrode assembly 100 needs to be greater than the threshold value, so that the plurality of protrusions 1122 remain spaced after the electrode assembly 100 is wound.

[0076] Referring to Figure 4 , Figure 4 A structural schematic view of a first tab of an electric core in an unfolded state is provided for some embodiments of the present application.

[0077] In some embodiments, the first surface 1121 can also include a surface of a side of the first tab 110 facing the winding center of the electrode assembly 100 and a surface of a side of the first tab 110 facing away from the winding center of the electrode assembly 100, and the interval between the plurality of protrusions 1122 on the surface of the side of the first tab 110 facing the winding center of the electrode assembly 100 needs to be greater than the threshold value, so that the plurality of protrusions 1122 remain spaced after the electrode assembly 100 is wound.

[0078] In some embodiments, the protrusions 1122 have a cylindrical structure, and the surface of the protrusions 1122 is arc-shaped.

[0079] By making the protrusions 1122 have a cylindrical structure, the preparation of the protrusions 1122 can be facilitated, and by making the surface of the protrusions 1122 arc-shaped, the possibility of damage to the separator 120 caused by interference between the protrusions 1122 and the separator 120 can be reduced, which is beneficial to reducing the possibility of short circuit of the electric core, thereby improving the safety of the electric core.

[0080] In some embodiments, the protrusions 1122 can also have a hillside structure, a hemispherical structure, a square structure, or other shapes.

[0081] Referring to Figure 5 , Figure 5 Another structural schematic view of a first tab of an electric core in an unfolded state is provided for some embodiments of the present application.

[0082] In some embodiments, a plurality of protrusions 1122 are arranged on a circle of the first tab 110, and the plurality of protrusions 1122 are arranged in an array.

[0083] By arranging multiple protrusions 1122 on one circle of the first tab 110, multiple portions of the first tab 110 can be spaced from the diaphragm 120 by the protrusions 1122, so as to facilitate the infiltration and storage of the electrolyte between the multiple portions of the first tab 110 and the diaphragm 120, and facilitate the improvement of the infiltration speed of the electrolyte. By arranging the multiple protrusions 1122 in an array, the protrusions 1122 can be uniformly distributed, so that the portions of the first tab 110 provided with the multiple protrusions 1122 are completely spaced from the diaphragm 120, further facilitating the infiltration and storage of the electrolyte between the portions of the first tab 110 provided with the protrusions 1122 and the diaphragm 120, and facilitating the further improvement of the infiltration speed of the electrolyte.

[0084] In some embodiments, the multiple protrusions 1122 are arranged along a first direction Y and a second direction Z respectively, wherein the first direction Y, the second direction Z, and the thickness direction X of the first tab are perpendicular to each other.

[0085] In other embodiments, the spacing distance between any two adjacent protrusions 1122 in the multiple protrusions 1122 is not equal.

[0086] In some embodiments, the first tab 110 includes a first current collector 111 and two layers of first active material layers 112, and the two layers of first active material layers 112 are arranged on the two side surfaces of the first current collector 111 along the thickness direction thereof, and the protrusions 1122 are integrally formed on the first active material layers 112.

[0087] By integrally forming the protrusions 1122 on the first active material layers 112, the preparation of the protrusions 1122 can be facilitated, and the possibility of the protrusions 1122 being separated from the first tab 110 under stress can be reduced.

[0088] In some embodiments, the protrusions 1122 can be formed by extruding the first tab 110 by a roller, and when the roller acts on the first tab 110, only the first active material layers 112 are deformed, and the first current collector 111 is not deformed, so as to reduce the possibility of damage to the first tab 110.

[0089] In other embodiments, the protrusions 1122 can be fixed on the first active material layers 112 by bonding or the like.

[0090] Referring to Figure 6 , Figure 6 The structure schematic view of the first tab of the battery cell in an unfolded state is provided for some embodiments of the present application.

[0091] In some embodiments, the second tab 130 has a second surface 1321 perpendicular to the thickness direction of the second tab 130, and the second surface 1321 is provided with second protrusions 1322.

[0092] By setting the second protrusion 1322 on the second surface 1321 of the second tab 130, the second protrusion 1322 can be in abutment with the separator 120 after the electrode assembly 100 is wound, and the distance between the second surface 1321 and the separator 120 in the thickness direction of the second tab is greater, so that a larger wicking space is formed between the second tab 130 and the separator 120, facilitating the storage and wicking of the electrolyte, which can reduce the possibility of metal ion precipitation during long cycle of the battery cell, thereby prolonging the service life of the battery cell and facilitating the improvement of the capacity and energy density of the battery cell.

[0093] In some embodiments, the average thickness of the second protrusion 1322 provided on a turn of the second tab 130 gradually increases outward from the winding center of the electrode assembly 100.

[0094] Since the length of the portion of the second tab 130 located in the outer turns is longer and the electrolyte is more difficult to wick outward from the winding center of the electrode assembly 100, by gradually increasing the average thickness of the second protrusion 1322 provided on a turn of the second tab 130 outward from the winding center of the electrode assembly 100, the storage and wicking of the electrolyte in the electrode assembly 100 can be further improved, thereby further reducing the possibility of metal ion precipitation during long cycle of the battery cell and further prolonging the service life of the battery cell.

[0095] If one second protrusion 1322 is provided on a turn of the second tab 130, the average thickness of the second protrusion 1322 refers to the thickness of the single second protrusion 1322. If multiple second protrusions 1322 are provided on a turn of the second tab 130, the average thickness of the second protrusion 1322 refers to the ratio of the total thickness of the multiple second protrusions 1322 to the number of the second protrusions 1322.

[0096] In some embodiments, the second protrusion 1322 is provided in the bending area 102.

[0097] Since the electrolyte is more difficult to wick in the bending area 102 of the electrode assembly 100 than in the flat area 101, and the possibility of metal ion precipitation is more likely to occur, by providing the second protrusion 1322 in the bending area 102, the wicking and storage of the electrolyte in the bending area 102 can be facilitated, the possibility of metal ion precipitation during long cycle of the battery cell can be reduced, thereby prolonging the service life of the battery cell and facilitating the improvement of the capacity and energy density of the battery cell.

[0098] In some embodiments, the second protrusions 1322 can also be arranged on the flat area 101. By arranging the second protrusions 1322 on the flat area 101, the electrolyte can be more easily infiltrated and stored on the flat area 101, which can reduce the possibility of metal ion precipitation caused by long cycle of the battery cell, thereby prolonging the service life of the battery cell and facilitating the improvement of the capacity and energy density of the battery cell.

[0099] In some embodiments, the projection area of the second protrusions 1322 arranged on a circle of the second tab 130 gradually increases along the thickness direction of the second tab from the winding center of the electrode assembly 100.

[0100] As the expansion pressure gradually increases for each circle of the second tab 130 from the winding center of the electrode assembly 100, the spacing distance between the second tab 130 and the separator 120 gradually decreases from the winding center of the electrode assembly 100. Therefore, by gradually increasing the projection area of the second protrusions 1322 arranged on a circle of the second tab 130 along the thickness direction of the second tab from the winding center of the electrode assembly 100, the support force of the second protrusions 1322 arranged on a circle of the second tab 130 gradually increases from the winding center of the electrode assembly 100, so that the spacing distance between the second tab 130 and the separator 120 is more uniform, which can further facilitate the infiltration and storage of the electrolyte between the second tab 130 and the separator 120, further reduce the possibility of metal ion precipitation caused by long cycle of the battery cell, further prolong the service life of the battery cell, and facilitate the further improvement of the capacity and energy density of the battery cell.

[0101] In some embodiments, the number of the second protrusions 1322 arranged on a circle of the second tab 130 gradually increases from the winding center of the electrode assembly 100.

[0102] As the expansion pressure gradually increases for each circle of the second tab 130 from the winding center of the electrode assembly 100, the spacing distance between the second tab 130 and the separator 120 gradually decreases from the winding center of the electrode assembly 100. Therefore, by gradually increasing the number of the second protrusions 1322 arranged on a circle of the second tab 130 from the winding center of the electrode assembly 100, the support force of the second protrusions 1322 arranged on a circle of the second tab 130 gradually increases from the winding center of the electrode assembly 100, so that the spacing distance between the second tab 130 and the separator 120 is more uniform, which can further facilitate the infiltration and storage of the electrolyte between the second tab 130 and the separator 120, further reduce the possibility of metal ion precipitation caused by long cycle of the battery cell, further prolong the service life of the battery cell, and facilitate the further improvement of the capacity and energy density of the battery cell.

[0103] In some embodiments, the second surface 1321 is away from the winding center of the electrode assembly 100.

[0104] By making the second surface 1321 away from the winding center of the electrode assembly 100, the possibility that the second protrusions 1322 press against each other during the winding of the electrode assembly 100, causing the spacing distance between the plurality of second protrusions 1322 to be too small to achieve the soaking and storage of the electrolyte, can be reduced, thereby enabling the soaking and storage effect of the electrolyte in the electrode assembly 100 to be better.

[0105] In some embodiments, the second electrode tab 130 includes a second current collector 131 and two layers of second active material layers 132, the two layers of second active material layers 132 are respectively arranged on the two side surfaces of the second current collector along the thickness direction thereof, and the second protrusions 1322 are integrally formed in the second active material layers 132.

[0106] In some embodiments, the first electrode tab 110 is a positive electrode tab, and the second electrode tab 130 is a negative electrode tab.

[0107] The battery mainly relies on the movement of metal ions between the positive electrode tab and the negative electrode tab to work. The positive electrode tab includes a positive electrode current collector (first current collector 111) and a positive electrode active material layer (first active material layer 112), the positive electrode active material layer is coated on the surface of the positive electrode current collector, and the part of the positive electrode current collector which is not coated with the positive electrode active material layer serves as a positive electrode tab 113 to realize the input or output of electric energy of the positive electrode tab through the positive electrode tab 113. Taking a lithium ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary material or lithium manganate, etc. The negative electrode tab includes a negative electrode current collector (second current collector 131) and a negative electrode active material layer (second active material layer 132), the negative electrode active material layer is coated on the surface of the negative electrode current collector, and the part of the negative electrode current collector which is not coated with the negative electrode active material layer serves as a negative electrode tab 133 to realize the input or output of electric energy of the negative electrode tab through the negative electrode tab 133. The material of the negative electrode current collector can be copper, and the negative electrode active material can be a carbon material or a silicon material, etc. The material of the separator can be polypropylene (PP) or polyethylene (PE), etc. The electrolyte can include organic solvents, electrolyte lithium salts, etc.

[0108] In some embodiments, the battery includes a shell (not shown in the figure), the shell is used to accommodate the electrode assembly 100 and the electrolyte.

[0109] In some embodiments, the shell can be made of a material with high strength, such as a metal material, e.g. steel, aluminum alloy, etc., so that the shell has high stress performance, thereby making the shell not easy to deform or break due to stress or environmental changes, thereby making the reliability of the battery higher.

[0110] In other embodiments, the outer shell can also be a non-metallic material with high strength, such as carbon fiber, hard plastic, etc.

[0111] The embodiments of the present application provide a kind of electric equipment, including the electric core provided by any of the above embodiments, and the electric core is used to provide electric energy.

[0112] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0113] The above is only the preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell comprising an electrode assembly, the electrode assembly being formed by winding a first electrode sheet, a separator, and a second electrode sheet in a stacked manner; the first electrode sheet having a first surface perpendicular to a thickness direction of the first electrode sheet and having a protrusion disposed on the first surface; It is characterized by: From the winding center of the electrode assembly toward the outside, the average thickness of the protrusions provided on a circle of the first pole piece gradually increases.

2. The battery cell according to claim 1, characterized in that The average thickness of the protrusion on the circle of the first pole sheet closest to the winding center of the electrode assembly is H0μm. The first pole sheet includes a first current collector and a first active material layer. The first active material layer is arranged on at least one side surface of the first current collector along its thickness direction. The thickness of the first active material layer is T1μm, 0.1×T1≤H0≤0.5×T1.

3. The battery cell according to claim 1, characterized in that The second pole piece includes a second current collector and a second active material layer, wherein the second active material layer is provided on at least one side surface of the second current collector along the thickness direction thereof; The average thickness of the protrusion of the first pole sheet at the Nth turn is Hμm, H≥H0+β×N×T2, H0≥β×T2, wherein H0 is the average thickness of the protrusion on the turn of the first pole sheet closest to the winding center of the electrode assembly, β=(the thickness of the battery cell when fully charged - the thickness of the battery cell when empty) / the thickness of the battery cell when empty, T2=(the thickness of the second pole sheet when empty - the thickness of the second current collector) / 2, N is the number of winding turns of the first pole sheet, and the units of H0 and T2 are μm.

4. The battery cell according to claim 1, characterized in that The first pole piece, the diaphragm and the second pole piece are wound to form two straight areas and two bent areas, and each bent area connects two ends of the two straight areas respectively; The protrusion is arranged in the bending area.

5. The battery cell according to claim 4, characterized in that: Each of the bending areas includes a plurality of bending segments, each of the bending segments is provided with a plurality of protrusions, and the plurality of protrusions on each of the bending segments have the same thickness.

6. The battery cell according to claim 1, characterized in that From the winding center of the electrode assembly toward the outside, along the thickness direction of the first electrode sheet, the projected area of ​​the protrusions provided on one circle of the first electrode sheet gradually increases.

7. The battery cell according to claim 1, characterized in that From the winding center of the electrode assembly outward, the number of the protrusions provided on a circle of the first pole piece gradually increases.

8. The battery cell according to claim 1, characterized in that The first surface faces away from a winding center of the electrode assembly.

9. The battery cell according to claim 1, characterized in that: The protrusion has a cylindrical structure, and the surface of the protrusion is arranged in an arc shape.

10. The battery cell according to claim 1, characterized in that A plurality of protrusions are provided on a circle of the first pole piece, and the plurality of protrusions are arranged in an array.

11. The battery cell according to claim 1, characterized in that The first pole piece includes a first current collector and two first active material layers. The two first active material layers are respectively arranged on both side surfaces of the first current collector along its thickness direction. The protrusion is integrally formed on the first active material layer.

12. The battery cell according to claim 1, characterized in that The first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.

13. An electrical device, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 12, wherein the battery cell is used to provide electrical energy.

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