CN219873594U - Battery and electronic equipment - Google Patents
Battery and electronic equipment Download PDFInfo
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- CN219873594U CN219873594U CN202321273698.5U CN202321273698U CN219873594U CN 219873594 U CN219873594 U CN 219873594U CN 202321273698 U CN202321273698 U CN 202321273698U CN 219873594 U CN219873594 U CN 219873594U
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- 239000011149 active material Substances 0.000 claims abstract description 28
- 229910052744 lithium Inorganic materials 0.000 abstract description 56
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 abstract description 53
- 229910052751 metal Inorganic materials 0.000 abstract description 24
- 239000002184 metal Substances 0.000 abstract description 24
- 239000003792 electrolyte Substances 0.000 abstract description 20
- 238000006243 chemical reaction Methods 0.000 abstract description 10
- 238000007086 side reaction Methods 0.000 abstract description 9
- 239000007795 chemical reaction product Substances 0.000 abstract description 5
- 230000020169 heat generation Effects 0.000 abstract description 5
- 239000007773 negative electrode material Substances 0.000 description 30
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 21
- 229910001416 lithium ion Inorganic materials 0.000 description 21
- 230000000052 comparative effect Effects 0.000 description 12
- 238000000034 method Methods 0.000 description 10
- 230000001502 supplementing effect Effects 0.000 description 9
- 238000010586 diagram Methods 0.000 description 8
- 239000006183 anode active material Substances 0.000 description 7
- 239000006258 conductive agent Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 239000011230 binding agent Substances 0.000 description 5
- 238000007600 charging Methods 0.000 description 5
- 238000007599 discharging Methods 0.000 description 4
- 239000007774 positive electrode material Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 238000010998 test method Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 230000002427 irreversible effect Effects 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 description 3
- 238000001878 scanning electron micrograph Methods 0.000 description 3
- 239000013589 supplement Substances 0.000 description 3
- 229920000049 Carbon (fiber) Polymers 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000004917 carbon fiber Substances 0.000 description 2
- 238000010277 constant-current charging Methods 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
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- 239000000463 material Substances 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000006257 cathode slurry Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
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- 238000007542 hardness measurement Methods 0.000 description 1
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- 238000002955 isolation Methods 0.000 description 1
- YWXYYJSYQOXTPL-SLPGGIOYSA-N isosorbide mononitrate Chemical group [O-][N+](=O)O[C@@H]1CO[C@@H]2[C@@H](O)CO[C@@H]21 YWXYYJSYQOXTPL-SLPGGIOYSA-N 0.000 description 1
- 239000003273 ketjen black Substances 0.000 description 1
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- 239000002048 multi walled nanotube Substances 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
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- 239000002985 plastic film Substances 0.000 description 1
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- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
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- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000002109 single walled nanotube Substances 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Secondary Cells (AREA)
Abstract
The utility model provides a battery and an electronic device. The first aspect of the utility model provides a battery comprising a first pole piece, wherein the first pole piece comprises a first current collector and a first active material layer arranged on the surface of the first current collector, and the surface, close to the first active material layer, of the first current collector comprises first bright areas and first dark areas which are alternately distributed. The battery provided by the utility model can avoid direct contact reaction of the metal lithium and the electrolyte, improves the utilization rate of the metal lithium, relieves the problem of heat generation of the battery caused by the reaction of the metal lithium and the electrolyte, and improves the safety of the battery; in addition, as no side reaction product exists between the surface of the first active material layer far away from the first current collector and the diaphragm, the diaphragm is well adhered, the problem of battery softening is avoided, and the hardness of the battery is improved.
Description
Technical Field
The utility model relates to a battery and electronic equipment, and relates to the technical field of batteries.
Background
With the increasing demands for electronic products and electric vehicles, the demands for battery energy density and service life are also increasing. For most electrode materials, irreversible loss of a large amount of active lithium is caused by irreversible reaction such as generation of an SEI film (solid electrolyte interface film) during the first charge and discharge. To compensate for this loss of active lithium, lithium replenishment techniques have been developed in the art to increase the energy density of the battery.
However, the lithium supplementing technology has the following problems: a. after the electrolyte is injected, the metal lithium reacts with the electrolyte vigorously, so that the utilization rate of lithium is reduced; b. the electrolyte reacts with the lithium metal to release heat, so that the temperature of the battery is increased, and the safety risk is brought; c. substances generated by side reaction of the lithium metal and the electrolyte are deposited on the surface of the pole piece, so that the adhesion between the diaphragm and the pole piece is blocked, the hardness of the battery is reduced, and the battery is easy to deform in the use process.
Disclosure of Invention
The utility model provides a battery which is used for relieving the problems of the existing lithium supplementing technology, improving the lithium supplementing effect and avoiding the problems of heat generation and softness of the battery caused by side reaction between metal lithium and electrolyte.
The utility model also provides electronic equipment comprising the battery.
The first aspect of the utility model provides a battery comprising a first pole piece, the first pole piece comprising a first current collector and a first active material layer arranged on the surface of the first current collector, wherein:
the surface of the first current collector, which is close to the first active material layer, comprises first bright areas and first dark areas, and the first bright areas and the first dark areas are alternately distributed.
In the battery described above, the surface of the first active material layer, which is close to the first current collector, includes second bright areas and second dark areas, and the second bright areas and the second dark areas are alternately distributed.
A battery as described above, the projection of the first open area onto the first current collector at least partially coinciding with the projection of the second open area onto the first current collector;
and/or the projection of the first dark region on the first current collector is at least partially overlapped with the projection of the second dark region on the first current collector.
The battery as described above, wherein the lengths of the first open region and the second open region are 20 μm to 4mm;
and/or the lengths of the first dark area and the second dark area are 20 mu m-4 mm.
The battery as described above, the total area of the first open area occupies 30% -90% of the surface area of the first current collector;
and/or, the total area of the second open area accounts for 30% -90% of the surface area of the first active material layer.
The maximum value of the height difference between the first bright area and the first dark area is |H2 max |，0.1μm≤|H1 max |≤10μm；
And/or the maximum value of the height difference between the second bright area and the second dark area is |H2 max |，0.1μm≤|H2 max |≤10μm。
The battery is characterized in that the first open area is in a convex structure relative to the first current collector, and the second open area is in a concave structure relative to the first active material layer;
or, the first open area is in a concave structure relative to the first current collector, and the second open area is in a convex structure relative to the first active material layer.
The battery as described above, the first current collector includes a current collector body and at least one protrusion formed to extend outwardly from one side of the current collector body;
the distance between a first open area closest to the edge of the current collector body and the edge of the current collector body along the length direction of the first current collector is not more than 4mm;
and/or, along the width direction of the first current collector, the distance between the first open area closest to the edge of the current collector body and the edge of the current collector body is not more than 4mm.
In the battery, the first current collector surface further comprises a second area, and the distance between a first open area closest to the second area and the second area along the length direction of the first current collector is not more than 2mm;
and/or, along the width direction of the first current collector, the distance between the first open area closest to the second area and the second area is not more than 2mm.
In the battery described above, the distance between the second open area closest to the edge of the first active material layer and the edge of the first active material layer along the longitudinal direction of the first active material layer is not greater than 4mm.
A second aspect of the utility model provides an electronic device comprising a battery as described in any one of the preceding claims.
In the battery provided by the utility model, the first current collector is provided with the first bright areas and the first dark areas which are alternately distributed on the surface close to the first active material layer, so that direct contact reaction of metal lithium and electrolyte can be avoided, the utilization rate of the metal lithium is improved, the problem of heat generation of the battery caused by the reaction of the metal lithium and the electrolyte is relieved, and the safety of the battery is improved; in addition, as no side reaction product exists between the surface of the first active material layer far away from the first current collector and the diaphragm, the diaphragm is well adhered, the problem of battery softening is avoided, and the hardness of the battery is improved.
Drawings
In order to more clearly illustrate the embodiments of the present utility model or the technical solutions of the prior art, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it will be obvious that the drawings in the following description are some embodiments of the present utility model, and that other drawings can be obtained according to these drawings without inventive effort to a person skilled in the art.
Fig. 1 is a schematic structural diagram of a negative electrode plate according to an embodiment of the present utility model;
fig. 2 is an SEM image of the surface of the negative current collector observed under a scanning electron microscope at 50 x magnification;
fig. 3 is an SEM image obtained by observing the surface of the anode active material layer near the anode current collector under a scanning electron microscope at a magnification of 50 times;
fig. 4 is an SEM image obtained by observing the surface of the anode active material layer away from the anode current collector under a scanning electron microscope at a magnification of 50 times;
fig. 5 is a schematic structural diagram of a negative current collector according to an embodiment of the present utility model;
fig. 6 is a schematic structural diagram of a negative current collector according to another embodiment of the present utility model;
fig. 7 is a schematic structural diagram of a negative current collector according to another embodiment of the present utility model;
fig. 8 is a schematic structural view of a negative current collector according to another embodiment of the present utility model;
fig. 9 is a schematic structural view of a negative electrode active material layer according to still another embodiment of the present utility model.
Reference numerals illustrate:
1-a negative electrode current collector;
101-a first open area;
102-a first dark region;
103-a second region;
2-a negative electrode active material layer;
201-a second open area;
202-a second dark region;
3-negative electrode tab.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, the technical solutions in the embodiments of the present utility model will be clearly and completely described in the following in conjunction with the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
The lithium is added into the cathode, and the lithium is added into the cathode slurry in the mixing process of the cathode, and the lithium is separated from the high-capacity material in the charging process so as to supplement irreversible capacity loss in the first charge and discharge. Whether the positive electrode is used for lithium supplement or the negative electrode is used for lithium supplement, the problems of low lithium utilization rate, high battery temperature and low battery hardness exist.
In order to solve the technical problem, a first aspect of the utility model provides a battery, which comprises a first pole piece, wherein the first pole piece comprises a first current collector and a first active material layer arranged on the surface of the first current collector, and the surface, close to the first active material layer, of the first current collector is provided with first bright areas and first dark areas which are alternately distributed.
The battery provided by the utility model is beneficial to avoiding direct contact reaction of the metal lithium and the electrolyte, improves the utilization rate of the metal lithium, relieves the problem of battery heat generation caused by the reaction of the metal lithium and the electrolyte, and improves the safety of the battery; in addition, as no side reaction product exists between the first active material layer far away from one side of the first current collector and the diaphragm, the diaphragm is well adhered, the problem of battery softening is avoided, and the hardness of the battery is improved.
In a specific implementation manner, the first electrode piece is an anode electrode piece, fig. 1 is a schematic structural diagram of the anode electrode piece provided by an embodiment of the present utility model, and as shown in fig. 1, the anode electrode piece includes an anode current collector 1 and an anode active material layer 2 located on the surface of the anode current collector 1, where:
the negative electrode current collector 1 refers to a base metal for attaching an active material in a negative electrode of a battery, and may be, for example, a conventional material such as copper foil, which includes upper and lower surfaces parallel to each other, and the negative electrode active material layer 2 is supported on the upper and/or lower surfaces of the negative electrode current collector 1.
In order to realize lithium supplementation of a negative electrode piece, metal lithium is placed between a negative electrode current collector 1 and a negative electrode active material layer 2 at intervals, after a battery is charged and discharged, under the existence of potential difference, the metal lithium loses electrons to form lithium ions, the lithium ions enter an electrolyte to form solvated lithium ions, the lithium ions are desolvated to form lithium ions to enter a negative electrode, and the lithium ions entering the negative electrode obtain electrons to form Li x C 6 An SEI film is formed on the surface of the negative electrode current collector 1, and the SEI film has the same composition as that of SEI film formed by normal charge and discharge, but has different contents and is thicker than the conventional SEI film, so that a macroscopic first bright region 101 and a macroscopic first dark region 102 as shown in FIG. 2 are formed on the surface of the negative electrode current collector 1, which is close to the negative electrode active material layer 2, wherein the first bright region 101 corresponds to a region of the negative electrode current collector, which is composited with metallic lithium, and the first dark region 102 corresponds to a region of the negative electrode current collector, which is free of metallic lithium.
In contrast to the negative current collector 1, during the charge and discharge process of the battery, the metal lithium also forms a thicker SEI film on the surface of the negative active material layer 2, which is close to the negative current collector 1, to form a macroscopic second bright area 201 and a macroscopic second dark area 202 as shown in fig. 3, and the projection of the first bright area 101 on the negative current collector 1 at least partially coincides with the projection of the second bright area 201 on the negative current collector, and the projection of the first dark area 102 on the negative current collector at least partially coincides with the projection of the second dark area 202 on the negative current collector.
And the surface of the anode active material layer 2 away from the anode current collector 1 has no thicker SEI film formation, no bright and dark regions, respectively, as shown in fig. 3, and a case as shown in fig. 4.
In one embodiment, with continued reference to FIGS. 2-3, the first and second open areas 101 and 201 are 20 μm to 4mm in length and/or the first and second dark areas 102 and 202 are 20 μm to 4mm in length.
The definition of the length, width and thickness in the present utility model is the same as the conventional definition in the art, that is, the direction of the longer side of the negative electrode sheet is taken as the length direction x, the direction of the shorter side is taken as the thickness direction z, the directions between the longer side and the shorter side are taken as the width direction y, and the length, width and thickness directions of the negative electrode current collector, the bright area, the dark area and the negative electrode active material layer are the same as the negative electrode sheet.
In a specific embodiment, the total area of the first open area 101 accounts for 30% -90% of the surface area of the negative electrode current collector 1, the surface of the negative electrode current collector 1 is the surface which is formed in the length direction and the width direction and is close to the negative electrode active material layer 2, and the problem of poor conductivity of the current collector caused by high inorganic salt content in metallic lithium can be avoided by limiting the coverage area of the first open area 101 on the surface of the negative electrode current collector 1.
In one embodiment, the difference in height between the first bright area 101 and the first dark area 102 has a maximum value of |h1 max |，0.1μm≤|H1 max The I is less than or equal to 10 mu m; and/or the maximum value of the difference in height between the second bright area 201 and the second dark area 202 is |h2 max |，0.1μm≤|H2 max |≤10μm。
It should be noted that, in the present utility model, the difference in height between the bright area and the dark area is an absolute value, that is, the first bright area may be higher or lower than the first dark area with respect to the negative electrode current collector, and the second bright area may be higher or lower than the second dark area with respect to the negative electrode active material layer, and the absolute value of the difference in height therebetween is 0.1 μm to 10 μm; in the testing process, the battery can be disassembled, the height difference between the bright area and the dark area on the surface of the negative electrode current collector and the negative electrode active material layer can be tested, or the negative electrode pieces obtained through disassembly can be grouped, the average value of the height differences between the bright area and the dark area in each group of negative electrode pieces is tested, and the maximum value of the average value of the height differences in each group of negative electrode pieces is taken as the height difference between the bright area and the dark area.
It can be understood that when the first open region 101 has a convex structure with respect to the anode current collector 1, then the second open region 201 opposite to the first open region 101 has a concave structure with respect to the anode active material layer 2;
alternatively, the first open region 101 has a concave structure with respect to the anode current collector 1, and the second open region 201 facing the first open region 101 has a convex structure with respect to the anode active material layer 2.
The surface of the negative electrode current collector 1 further comprises a second area 103 connected with the negative electrode tab or directly used as the negative electrode tab 3, and when the structures of the negative electrode tab 3 are different, the partition conditions of the surface of the negative electrode current collector 1 are different according to the different battery structures.
In a specific implementation manner, fig. 5 is a schematic structural diagram of a negative current collector according to an embodiment of the present utility model, as shown in fig. 5, the negative current collector 1 includes a current collector body and a protrusion formed by extending outwards from one side of the current collector body, where the protrusion is used as a second area 103 on the surface of the negative current collector 1, and may be connected to a negative tab or be used as a part of the negative tab; along the length direction of the negative current collector 1, the distance L3 between the first open area closest to the edge of the current collector body and the edge of the current collector body is not more than 4mm; and/or, along the width direction of the negative current collector, the distance L4 between the first open area closest to the edge of the current collector body and the edge of the current collector body is not more than 4mm.
Fig. 6 is a schematic structural diagram of a negative current collector according to another embodiment of the present utility model, as shown in fig. 6, for a negative electrode tab of a multi-tab structure, the negative current collector 1 includes a current collector body and at least two protrusions formed by extending outwards from one side of the current collector body, i.e. at least two second regions 103; as in fig. 5, along the length direction of the negative electrode current collector 1, the distance L3 between the first open area closest to the edge of the current collector body and the edge of the current collector body is not more than 4mm; and/or, along the width direction of the negative current collector, the distance L4 between the first open area closest to the edge of the current collector body and the edge of the current collector body is not more than 4mm.
Fig. 7 is a schematic structural diagram of a negative current collector according to another embodiment of the present utility model, as shown in fig. 7, for a negative electrode tab of a CTP structure, a second area 103 for connecting a negative electrode tab 3 is located at a middle portion of a negative current collector 1, and a first open area 101 and a first dark area 102 are distributed on both sides of the second area, and a distance L5 between the first open area and the second area, which is closest to the second area 103, is not greater than 2mm along a length direction of the negative current collector; and/or, the distance L6 between the first open area closest to the second area and the second area along the width direction of the negative electrode current collector is not more than 2mm.
In addition, along the length direction of the negative current collector 1, the distance L3 between the first bright area closest to the edge of the current collector body and the edge of the current collector body is not more than 4mm; and/or, along the width direction of the negative current collector, the distance L4 between the first open area closest to the edge of the current collector body and the edge of the current collector body is not more than 4mm.
Fig. 8 is a schematic structural view of a negative electrode current collector according to another embodiment of the present utility model, and fig. 9 is a schematic structural view of a negative electrode active material layer according to another embodiment of the present utility model, as shown in fig. 8 to 9, for a negative electrode tab in a wound structure, a second region 103 for connecting a negative electrode tab 3 is located at an edge position of the negative electrode current collector 1, and a length of the negative electrode current collector 1 is greater than a length of the negative electrode active material layer 2, so that a region, which is not covered by the negative electrode active material layer 2, on a surface of the negative electrode current collector 1 has no first open region 101, and a distance L7 between a second open region 201 closest to the edge of the negative electrode active material layer 2 and the edge of the negative electrode active material layer is not greater than 4mm along a length direction of the negative electrode active material layer 2.
Further, in the width direction of the anode current collector 1, a distance L4 from the first open area 101 closest to the anode current collector body edge is not more than 4mm.
The negative electrode active material layer 2 comprises a negative electrode active material, a conductive agent and a binder, wherein the negative electrode active material comprises one or more of artificial graphite, natural graphite, hard carbon, mesophase carbon microspheres, lithium titanate, silicon carbon and silicon oxide, and the conductive agent comprises one or more of conductive carbon black, acetylene black, ketjen black, conductive graphite, conductive carbon fiber, carbon nanotube, single-walled carbon nanotube, multi-walled carbon nanotube and carbon fiber; the binder comprises one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and lithium Polyacrylate (PAALi).
The battery provided by the utility model further comprises a positive electrode plate, a diaphragm and electrolyte, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer arranged on the surface of the positive electrode current collector, and the positive electrode active material layer comprises a positive electrode active material, a conductive agent and a binder. The choice of the positive electrode active material, the conductive agent and the binder is not particularly limited and may be selected conventionally in the art.
The separator and electrolyte are not particularly required to be selected, and are all conventional in the art.
In general, the negative electrode sheet is prepared by dispersing a negative electrode active material, a conductive agent, and a binder in an aqueous solution to prepare a negative electrode active material layer slurry, and then coating the negative electrode active material layer slurry on the negative electrode current collector 1 to obtain a negative electrode active material layer 2. However, in order to avoid the reaction between solvent water and metal lithium, the utility model firstly presses the metal lithium into a proper thickness and compounds the metal lithium on the surface of the negative electrode current collector 1, then prepares the negative electrode active material layer 2 by using a dry method, then presses the solvent-free negative electrode active material layer onto the negative electrode current collector compounded with the metal lithium by using a dry electrode technology to obtain the negative electrode piece, finally assembles the prepared negative electrode piece, the positive electrode piece and the diaphragm to obtain a battery cell, and encapsulates, fills and discharges the battery cell, and indicates that lithium supplementing is successful when the surface of the negative electrode current collector and the negative electrode active material layer form alternately distributed open areas and dark areas.
It is understood that the first pole piece may be a positive pole piece, and those skilled in the art may set the first pole piece as needed.
In conclusion, the battery structure provided by the utility model can avoid direct contact reaction of the metal lithium and the electrolyte, improve the utilization rate of the metal lithium, reduce the heat generation of the battery caused by the reaction of the metal lithium and the electrolyte, and improve the safety of the battery; meanwhile, as no side reaction product exists between the surface of the active material layer far away from the current collector and the diaphragm, the diaphragm is well bonded, the problem of softening of the lithium ion battery is avoided, and the hardness of the battery is improved.
A second aspect of the utility model provides an electronic device comprising a battery as described in any one of the preceding claims.
The battery may be used as a power source or energy storage unit for the electronic device. The device may be, but is not limited to, a mobile device (e.g., a cell phone, tablet computer, notebook computer, etc.), an electric vehicle (e.g., a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf car, an electric truck, etc.), and the like.
For mobile devices such as mobile phones, tablet computers, notebook computers, etc., it is generally required to be light and thin, and lithium ion batteries can be used as power sources.
The electronic equipment provided by the utility model comprises the battery provided by the first aspect, and correspondingly has the beneficial effects realized by the battery.
The utility model is illustrated in detail below with reference to specific examples:
example 1
The preparation method of the lithium ion battery provided by the embodiment comprises the following steps:
step 1, premixing a negative electrode active material and a conductive agent for 1h by adopting a stirrer, and controlling the temperature to be 25 ℃ by cooling water in the process;
step 2, adding PTFE into the premix for fiberization, closing cooling water, controlling the temperature at 100 ℃ and fiberizing for 10min;
and 3, rolling and forming the powder by a double-steel-belt calender after passing through a 100 ℃ internal mixer for 30 seconds, and obtaining the required thickness of 0.1mm through multiple times of rolling.
Step 4, in a dry environment, pressing the lithium ingot to a micron level, and then covering the lithium ingot with a negative electrode current collector, wherein the thickness of the lithium ingot is 3.4 mu m, and the lithium supplementing amount is 0.18mg/cm 2 And carrying out roller lamination on the dry pole piece and the lamination current collector by a hot roller to obtain the negative pole piece.
And 5, sequentially stacking the negative electrode plate, the positive electrode plate and the diaphragm, enabling the isolating film to be positioned between the positive electrode and the negative electrode to play a role of isolation, then winding to obtain a bare cell, placing the bare cell in an outer packaging foil aluminum plastic film, injecting electrolyte into the bare cell, and performing vacuum packaging, standing, formation (0.1C constant current charging 4% SOC, 0.2C constant current charging to 10% SOC), shaping, capacity testing and other procedures to obtain the soft package lithium ion battery.
Comparative example 1
The lithium ion battery provided in this comparative example can be referred to example 1, except that the lithium supplementing amount in the negative electrode tab is 0.
Comparative example 2
The lithium ion battery provided in this comparative example can be referred to example 1, except that metallic lithium is coated on the surface of the anode active material layer remote from the current collector.
In the lithium ion batteries provided in example 1 and comparative examples 1 to 2, the surfaces of the negative electrode current collector and the negative electrode active material layer close to each other included alternately distributed bright and dark regions, as shown in fig. 2 to 4, whereas in the lithium ion batteries provided in comparative examples 1 to 2, the surfaces of the negative electrode current collector and the negative electrode active material layer close to each other did not have alternately distributed bright and dark regions.
The lithium ion batteries provided in example 1 and comparative examples 1 to 2 were tested for temperature, first efficiency, capacity and hardness, and the test methods are as follows, and the test results are shown in table 1:
the temperature test method comprises the following steps: after the battery is injected for 30min, the handheld temperature sensor is detected at a distance of 1-5 cm from the middle position of the battery core.
The first efficiency test method comprises the following steps: placing the lithium ion battery for 10min, then charging for 10min with 30mA current, and charging to the upper limit cut-off voltage with 0.1C constant current after placing for 10min, wherein the cut-off current is 10mA; and finally, after the rest for 10min, discharging to the lower limit voltage by using a constant current of 0.1C.
The capacity test method comprises the following steps: and placing the lithium ion battery for 10min, discharging at a constant current of 0.5C to a final voltage, placing for 10min, charging at a constant current and constant voltage of 0.33C to an upper limit cutoff voltage, stopping at a voltage of 0.05C, placing for 10min, and discharging at a constant current of 0.33C to a lower limit voltage to obtain the battery capacity.
Hardness testing method: testing the internal resistance of the incoming material voltage at 25 ℃, if the voltage is not in the range of 3.86+/-0.04V, discharging to 3V by 0.2C, charging to 3.88V by 0.5C, cutting off by 0.05C, setting the descending speed of equipment to 10mm/min, adjusting the span of a clamp base, (the span is 0.7 times of the cell width according to the width of a coil core), and carrying out the downward displacement: 0.8mm, the maximum force value of the test force value with displacement.
Table 1 test results of the batteries provided in example 1 and comparative examples 1 to 2
| Lithium supplementing amount mg/cm 2 | Cell temperature | First effect | capacity/mAh | Cell hardness/N | |
| Example 1 | 0.18 | 25℃ | 86.21％ | 4398 | 398 |
| Comparative example 1 | / | / | 73.77％ | 3841 | 400 |
| Comparative example 2 | 0.18 | 40℃～45℃ | 85.01％ | 4356 | 186 |
As can be seen from table 1, the initial efficiency of the lithium ion battery provided in comparative example 1 was only 73.77%, and the initial efficiency of the lithium ion battery was improved by supplementing lithium. According to comparative example 2 and example 1, the lithium supplementing layer is placed between the negative electrode current collector and the negative electrode active material layer, and the electrolyte is contacted with the metal lithium more slowly, so that the side reaction between the electrolyte and the metal lithium is reduced, the utilization rate of the metal lithium is improved, and the initial efficiency and the capacity of the battery are improved; meanwhile, due to the reduction of side reaction between the lithium metal and the electrolyte, the temperature of the battery is stabilized at 25 ℃, so that the problem of heating of the lithium ion battery is avoided; in addition, as no side reaction product exists between the negative electrode far away from one side of the current collector and the diaphragm, the diaphragm is well bonded, the problem of softness of the lithium ion battery is avoided, and the hardness of the battery is improved.
The terms first and second in the description and claims of the utility model and in the description of the figures above are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the utility model described herein may be capable of operation in sequences other than those illustrated or otherwise described.
The above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the same; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the utility model.
Claims (11)
1. A battery comprising a first pole piece comprising a first current collector and a first active material layer disposed on a surface of the first current collector, wherein:
the surface of the first current collector, which is close to the first active material layer, comprises first bright areas and first dark areas, and the first bright areas and the first dark areas are alternately distributed.
2. The battery of claim 1, wherein the surface of the first active material layer adjacent to the first current collector comprises second open areas and second dark areas, the second open areas and second dark areas being alternately distributed.
3. The battery of claim 2, wherein the projection of the first open area onto the first current collector at least partially coincides with the projection of the second open area onto the first current collector;
and/or the projection of the first dark region on the first current collector is at least partially overlapped with the projection of the second dark region on the first current collector.
4. The battery of claim 2, wherein the first open region and the second open region have a length of 20 μιη to 4mm;
and/or the lengths of the first dark area and the second dark area are 20 mu m-4 mm.
5. The battery of claim 2, wherein the total area of the first open area is between 30% and 90% of the surface area of the first current collector;
and/or, the total area of the second open area accounts for 30% -90% of the surface area of the first active material layer.
6. The battery according to claim 2, wherein a maximum value of the difference in height between the first bright area and the first dark area is |h1 max |，0.1μm≤|H1 max |≤10μm；
And/orThe maximum value of the height difference between the second bright area and the second dark area is |H2 max |，0.1μm≤|H2 max |≤10μm。
7. The battery of claim 2, wherein the first open region is a raised structure relative to the first current collector and the second open region is a recessed structure relative to the first active material layer;
or, the first open area is in a concave structure relative to the first current collector, and the second open area is in a convex structure relative to the first active material layer.
8. The battery of claim 1, wherein the first current collector comprises a current collector body and at least one protrusion extending outwardly from one side of the current collector body;
the distance between a first open area closest to the edge of the current collector body and the edge of the current collector body along the length direction of the first current collector is not more than 4mm;
and/or, along the width direction of the first current collector, the distance between the first open area closest to the edge of the current collector body and the edge of the current collector body is not more than 4mm.
9. The battery according to claim 1, wherein the first current collector surface further comprises a second region, the tab is connected to the second region, and a distance between a first open area closest to the second region and the second region along the length direction of the first current collector is not more than 2mm;
and/or, along the width direction of the first current collector, the distance between the first open area closest to the second area and the second area is not more than 2mm.
10. The battery of claim 2, wherein a distance from the first active material layer edge of a second open area closest to the first active material layer edge is no greater than 4mm along the length of the first active material layer.
11. An electronic device comprising a battery according to any one of claims 1 to 10.
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