CN114335432A - Metal lithium belt, negative plate and battery - Google Patents
Metal lithium belt, negative plate and battery Download PDFInfo
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Abstract
The invention provides a metal lithium belt, a negative plate and a battery, wherein the metal lithium belt comprises a substrate and a lithium belt body, the lithium belt body is arranged on the substrate, a plurality of first gaps and a plurality of second gaps are formed in the lithium belt body so as to divide the lithium belt body into a plurality of lithium belt strips, and included angles are formed between the first gaps and the second gaps. The metal lithium belt, the negative plate and the battery provided by the invention can prevent the negative active material from falling off and the negative plate from excessively extending in the pressing process, and can quickly finish the lithium supplementing process, thereby improving the lithium supplementing efficiency.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a metal lithium strip, a negative plate and a battery.
Background
The lithium ion battery is widely used as a power battery of a new energy automobile, and along with the continuous improvement of the requirements of the new energy automobile on the endurance mileage, the energy density of the lithium ion battery also needs to be continuously improved.
The lithium ion battery comprises a positive electrode, a negative electrode, a diaphragm, electrolyte and the like. Lithium ions in the positive electrode and lithium ions in the electrolyte are gathered to the negative electrode during charging to obtain electrons, and the electrons are reduced to lithium embedded in the active material of the negative electrode. During discharging, lithium embedded in the negative electrode material loses electrons and enters into the electrolyte, and lithium ions in the electrolyte move to the positive electrode. The capacity of the negative electrode material to accommodate lithium ions determines the energy density of the lithium ion battery. The silicon-doped cathode has high theoretical specific capacity and is an ideal material for improving the energy density of the lithium ion battery. However, the first efficiency of the silicon-doped negative electrode is low, which in turn causes the energy density of the lithium ion battery to be reduced, so that the first efficiency of the silicon-doped negative electrode needs to be improved by a negative electrode lithium supplement process, and the energy density of the lithium ion battery is further improved. The conventional negative electrode lithium supplement process adopts a whole metal lithium belt, and silicon-doped negative electrode lithium supplement is carried out in a mode of pressing the whole metal lithium belt and a negative electrode plate.
When the whole piece of metal lithium belt is used for lithium supplement, the pressure for pressing the negative electrode and the whole piece of metal lithium belt together is large, so that the negative electrode is subjected to powder falling and excessive extension, and the lithium supplement efficiency is low.
Disclosure of Invention
The invention provides a metal lithium belt, a negative plate and a battery, which can prevent a negative active material from falling off and the negative plate from excessively extending in a pressing process, quickly finish a lithium supplementing process and improve the lithium supplementing efficiency.
The invention provides a metal lithium belt, which comprises a base material and a lithium belt body, wherein the lithium belt body is arranged on the base material, a plurality of first gaps and a plurality of second gaps are formed in the lithium belt body so as to divide the lithium belt body into a plurality of lithium belt strips, and an included angle is formed between the first gaps and the second gaps.
In one possible embodiment, the invention provides a metallic lithium ribbon having a bulk thickness greater than or equal to 1 μm and less than or equal to 10 μm.
In one possible embodiment, the invention provides a lithium metal strip having a bulk areal density of 0.1mg/cm or greater2And is less than or equal to 0.4mg/cm2。
In one possible embodiment, the invention provides a lithium metal strip, the lithium strip body having a first direction and a second direction perpendicular to each other, each lithium strip extending in the second direction.
In one possible embodiment, the invention provides a lithium metal tape, wherein the size of the lithium tape strip along the first direction is 100 μm-1500 μm;
and/or the lithium ribbon has a dimension in the second direction greater than or equal to 2 mm.
In one possible embodiment, the present invention provides a lithium metal strip, wherein the width of the first gap is less than or equal to 1500 μm.
In a possible implementation manner, the metallic lithium belt provided by the invention further comprises a release agent layer, and the substrate, the release agent layer and the lithium belt body are sequentially stacked.
The invention also provides a negative plate which comprises a negative current collector, an active substance layer and the metal lithium belt, wherein the active substance layer is coated on the negative current collector, and the metal lithium belt is pressed on the active substance layer.
In one possible embodiment, the negative electrode sheet provided by the present invention has an active material layer that is a silicon-doped active material layer, and the content of silicon in the silicon-doped active material layer is less than or equal to 30%.
The invention also provides a battery, which comprises a positive plate, a diaphragm and the negative plate, wherein the diaphragm is positioned between the positive plate and the negative plate.
The invention provides a metal lithium belt, a negative plate and a battery, wherein the metal lithium belt is provided with a substrate and a lithium belt body, the lithium belt body is arranged on the substrate so as to be stored and transferred, the lithium belt body is of a pore structure with a plurality of first gaps and a plurality of second gaps, the lithium belt body is divided into a plurality of lithium belt strips by the first gaps and the second gaps, an included angle is formed between the first gaps and the second gaps, so that the lithium belt strips are uniformly distributed on the lithium belt body, the surface of the lithium belt body has certain roughness by the first gaps and the second gaps distributed on the lithium belt body, the metal lithium belt and a silicon-doped negative electrode can be pressed by small pressure, thereby the falling of a negative active material in the pressing process can be prevented, the excessive extension of the negative plate can be prevented, electrolyte flows through the first gaps and the second gaps to infiltrate the surface of the lithium belt body and the silicon-doped negative electrode, lithium ions on the lithium belt strip enter the silicon-doped negative electrode through electrolyte, the soaking of the electrolyte and the uniformly distributed lithium strips enable the lithium supplement process to be completed quickly, the aging reaction is quick, and the lithium supplement efficiency is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a lithium metal strip provided in an embodiment of the present invention;
fig. 2 is a side view of a lithium metal strip according to an embodiment of the present invention.
Description of the reference numerals
100-a substrate;
200-a lithium ribbon body;
210-a first gap;
220-a second gap;
230-lithium tape;
300-a release agent layer;
a-a first direction;
b-a second direction;
l-substrate length;
w-width of the substrate;
w1-lithium tape width;
l1-lithium tape length.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present application, it should be noted that unless otherwise specifically stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning a fixed connection, an indirect connection through intervening media, a connection between two elements, or an interaction between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application.
The terms "first," "second," and "third" (if any) in the description and claims of this application and the above-described drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein.
Moreover, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or maintenance tool that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or maintenance tool.
The lithium ion battery is widely used as a power battery of a new energy automobile, and along with the continuous improvement of the requirements of the new energy automobile on the endurance mileage, the energy density of the lithium ion battery also needs to be continuously improved. Wherein, the energy density refers to the electric energy released by the average unit volume or mass of the lithium ion battery. The greater the energy density of a lithium ion battery, the more electricity stored per unit volume, or weight.
The lithium ion battery comprises a positive electrode, a negative electrode, a diaphragm, electrolyte and the like. Lithium ions in the positive electrode and lithium ions in the electrolyte are collected to the negative electrode during charging, and electrons are obtained and reduced to lithium and inserted into the active material of the negative electrode. During discharging, lithium embedded in the negative electrode material loses electrons and enters into the electrolyte, and lithium ions in the electrolyte move to the positive electrode.
The capacity of the negative electrode material to accommodate lithium ions determines the energy density of the lithium ion battery. The theoretical specific capacity of the silicon material is usually more than 4200mAh/g, the theoretical specific capacity of the graphite is 372mAh/g, and the theoretical specific capacity of the silicon material is far higher than that of the graphite, so that the silicon material is an ideal substitute material of the graphite. The negative electrode sheet coated with the negative electrode active material containing graphite on the negative electrode current collector is called a graphite negative electrode, and the negative electrode sheet coated with the negative electrode active material doped with silicon (including pure silicon, silicon oxygen, silicon carbon or the like) in a certain proportion on the negative electrode current collector is called a silicon-doped negative electrode.
However, the first efficiency of the silicon-doped negative electrode is low, wherein the first efficiency is the ratio of the discharged capacity of the lithium ion battery after the lithium ion battery is charged fully for the first time to the first charged capacity, the value of the discharged capacity is lower than the charged capacity, and the conversion efficiency is called the first efficiency. The first inefficiency in turn leads to a low energy density of the cell. Therefore, the first efficiency of the silicon-doped negative electrode needs to be improved by a negative electrode lithium supplement process, so that the energy density of the lithium ion battery is improved.
The lithium supplement of the silicon-doped negative electrode is carried out by the conventional negative electrode lithium supplement process in a way of pressing the whole metal lithium band with the thickness of 8-20 mu m with the negative electrode plate. The whole metal lithium belt has large thickness and no gap, so that the whole metal lithium belt has large surface capacity and uncontrollable lithium supplement amount, excessive lithium supplement can be caused, and further a series of problems of slow aging reaction, serious side reaction, lithium precipitation of a negative electrode, softening of a battery and the like of the lithium ion battery can be caused.
Specifically, the whole metal lithium belt has no gap, and the electrolyte is difficult to soak, so that the aging reaction is slow, and the production efficiency of the lithium ion battery is seriously influenced; excessive side reactions can consume lithium ions in the lithium ion battery, resulting in reduction of energy density of the lithium ion battery; the lithium precipitation of the negative electrode causes lithium metal particles to adhere to the surface of the negative electrode, the metal particles risking to pierce the separator; the products of the side reaction can be accumulated on the surface of the negative electrode material, so that the adhesion failure of the diaphragm and the negative electrode plate is caused, and the battery is in a soft state.
In order to reduce the lithium supplement amount, the metal lithium belt with the thickness of 8-20 μm can be rolled into an ultrathin metal lithium belt with the thickness of 3-5 μm, but the ultrathin metal lithium belt needs larger pressure to be pressed with the negative plate, so that the silicon-doped negative material falls off from the current collector and the current collector is excessively expanded.
Based on the metal lithium belt, the negative plate and the battery, the invention can prevent the negative active material from falling off and the negative plate from excessively extending in the pressing process, quickly finish the lithium supplementing process and improve the lithium supplementing efficiency.
Fig. 1 is a schematic structural diagram of a lithium metal strip provided in an embodiment of the present invention; fig. 2 is a side view of a lithium metal strip according to an embodiment of the present invention. As shown in fig. 1 and 2, the lithium metal ribbon provided by the present invention includes a substrate 100 and a lithium ribbon body 200, wherein the lithium ribbon body 200 is disposed on the substrate 100, and the lithium ribbon body 200 has a plurality of first gaps 210 and a plurality of second gaps 220 to divide the lithium ribbon body 200 into a plurality of lithium ribbon strips 230, and an included angle is formed between the first gaps 210 and the second gaps 220.
The metal lithium belt is used for supplementing lithium of the silicon-doped negative electrode, and specifically, the main process steps of the lithium ion battery comprise: the preparation method comprises the steps of preparing a positive electrode, preparing a negative electrode (the preparation of the silicon-doped negative electrode is referred to in the application), winding, injecting electrolyte, aging, sealing and the like. The first efficiency of lithium ion batteries using silicon-doped cathodes is low and needs to be improved by supplementing lithium ions to the cathode.
Lithium ions are inserted into the negative electrode through the following two processes. The first process is that after the silicon-doped negative electrode is prepared, the metal lithium belt and the silicon-doped negative electrode are pressed, and a small part of lithium ions enter the silicon-doped negative electrode in a solid-phase embedding mode. And the second process is that after the anode, the diaphragm and the silicon-doped cathode are wound into a cell and electrolyte is injected, most of the remaining lithium ions are embedded into the silicon-doped cathode through the infiltration of the electrolyte in the aging process, and the lithium supplement of the silicon-doped cathode is completed.
Wherein, the lithium metal is a soft metal, and the ultra-thin lithium ribbon needs the substrate 100 to support the lithium ribbon body 200, and the lithium ribbon body 200 is disposed on the substrate 100 for easy transfer. Specifically, the lithium ribbon body 200 is laid on the substrate 100, one surface of the lithium ribbon body 200 in the metal lithium ribbon is in contact with the silicon-doped negative electrode, a certain load is applied to the metal lithium ribbon and the silicon-doped negative electrode, and after the lithium ribbon body 200 and the silicon-doped negative electrode are pressed, the substrate 100 is peeled off, so that the lithium ribbon body 200 is transferred.
The lithium ribbon body 200 is laid on the substrate 100, and the lithium ribbon body 200 may be obtained by an asynchronous rolling process. Asynchronous rolling refers to a rolling method in which the surface linear velocities of two working rolls are not equal, and is also called asymmetric rolling.
In a specific implementation, a lithium metal foil with a thickness of about 1200 μm is rolled into the lithium ribbon body 200 asynchronously, since a shearing force is generated in a deformation region of the lithium metal foil during the asynchronous rolling, and the lithium metal itself is a soft metal, so that a first gap 210 and a second gap 220 are formed on the lithium ribbon body 200 while the lithium metal foil is rolled to be thin, the first gap 210 and the second gap 220 are uniformly distributed on the lithium ribbon body 200, and the first gap 210 and the second gap 220 divide the lithium ribbon body 200 into a plurality of lithium ribbon strips 230. In the present embodiment, the included angle between the first gap 210 and the second gap 220 varies in the range of 0 ° to 90 °, so that the plurality of lithium ribbon strips 230 are uniformly distributed on the lithium ribbon body 200.
The lithium strips 230 are sources of lithium ions in the lithium supplementing process of the silicon-doped negative electrode, the lithium strips 230 are strip-shaped, and the lithium strips 230 are connected with each other to form a whole, so that the lithium strip body 200 is transferred to the base material 100. With continued reference to fig. 1, the individual lithium ribbon strips 230 may be connected along their extension direction, the individual lithium ribbon strips 230 may be connected along a direction perpendicular to their extension direction, and the individual lithium ribbon strips 230 may also be connected at an angle to their extension direction.
The first gap 210 and the second gap 220 distributed on the lithium ribbon body 200 enable the surface of the lithium ribbon body 200 to have certain roughness, and when the metal lithium ribbon and the silicon-doped negative electrode are pressed, the metal lithium ribbon and the silicon-doped negative electrode can be pressed by small pressure, so that the negative electrode active material can be prevented from falling off in the pressing process, and the negative electrode sheet can be prevented from being excessively extended.
After the electrolyte is injected after winding, the electrolyte infiltrates the lithium ribbon body 200 and the surface of the silicon-doped negative electrode through the first gap 210 and the second gap 220 during aging, and lithium ions on the lithium ribbon strips 230 enter the silicon-doped negative electrode through the electrolyte to complete a lithium supplementing process. Since the lithium ribbon 230 is uniformly distributed on the lithium ribbon body 200, lithium ions are uniformly distributed even when entering the silicon-doped cathode, and do not migrate again according to the density difference of the lithium ions. The soaking of the electrolyte and the lithium strips 230 uniformly distributed enable the lithium supplementing process to be completed quickly, and the aging reaction is quick, so that the production efficiency of the lithium ion battery is improved.
The invention provides a metallic lithium belt, which is characterized in that a substrate 100 and a lithium belt body 200 are arranged, the lithium belt body 200 is arranged on the substrate 100 for storage and transfer, the lithium belt body 100 is a pore structure with a plurality of first gaps 210 and a plurality of second gaps 220, the lithium belt body 200 is divided into a plurality of lithium belt strips 230 by the first gaps 210 and the second gaps 220, an included angle is formed between the first gaps 210 and the second gaps 220, so that the lithium belt strips 230 are uniformly distributed on the lithium belt body 200, the surfaces of the lithium belt body 200 have certain roughness by the first gaps 210 and the second gaps 220 distributed on the lithium belt body 200, the metallic lithium belt and a silicon-doped negative electrode can be pressed by small pressure, thereby the negative active material can be prevented from falling off in the pressing process and the excessive extension of the negative electrode sheet can be prevented, electrolyte flows through the first gaps 210 and the second gaps 220 to infiltrate the surfaces of the lithium belt body 200 and the silicon-doped negative electrode, lithium ions on the lithium strip 230 enter the silicon-doped negative electrode through the electrolyte, and the lithium supplementing process is rapidly finished and the aging reaction is rapid due to the soaking of the electrolyte and the uniformly distributed lithium strip 230.
In the present embodiment, the thickness of the lithium ribbon body 200 is greater than or equal to 1 μm and less than or equal to 10 μm.
In particular implementations, the thickness of the lithium ribbon body 200 is not convenient to measure directly, and thus the equivalent thickness of the lithium ribbon body 200 is characterized by the ratio of the mass of the lithium ribbon body 200 to the lithium metal density. Since the first and second gaps 210 and 220 are provided, the weight of the lithium ribbon body 200 per unit area is less than that of a continuous metallic lithium foil, and when the equivalent thickness of the lithium ribbon body 200 varies between 1 μm and 10 μm, the corresponding lithium supplement surface capacity is 0.20mAh/cm2-1.23mAh/cm2To change between.
For example, when the silicon material content of the silicon-doped negative electrode is 20%, the amount of lithium supplement required to increase the first effect to 93% is 730mAh, and the surface capacity is 0.61mAh/cm on average over the entire surface2When the thickness of the lithium ribbon body 200 was 3 μm, the surface capacity was 0.61mAh/cm2The lithium supplement requirement of the silicon-doped negative electrode can be met.
When the thickness of the lithium belt body 200 is less than 1 μm, the lithium-supplementing surface capacity is less than 0.2mAh/cm2The surface capacity of the metal lithium strip is low, the lithium strip cannot supplement the amount of lithium ions consumed during first charge and discharge, and the effect of improving the first effect cannot be achieved. When the thickness of the lithium ribbon body 200 is greater than 10 μm, the lithium supplement may be excessive.
In some embodiments, the areal density of the lithium ribbon body 200 is greater than or equal to 0.1mg/cm2And is less than or equal to 0.4mg/cm2。
Because the first gap 210 and the second gap 220 are arranged on the lithium ribbon body 200, the surface density of the lithium ribbon body 200 is less than that of a lithium foil without gaps and with the same thickness, and the surface density of the lithium ribbon body 200 is 0.1mg/cm according to different lithium supplement amounts of silicon-doped cathodes2And 0.4mg/cm2The change of the lithium ion battery can not cause the phenomenon of excessive lithium supplement.
The lithium ribbon body 200 is manufactured by rolling, and the thickness of the lithium ribbon body 200 and the number and size of the first and second gaps 210 and 220 and the lithium ribbon strips 230 may be adjusted by changing rolling parameters when rolling.
Specifically, the rolling parameters can be changed by selecting working rolls with different radiuses, or by adjusting the speed of the working rolls, the pressure of the working rolls, or the friction coefficient between the base material and the lithium foil.
The silicon-doped negative electrode can be formed by materials such as pure silicon, silicon carbon or silicon oxygen, and different silicon-doped negative electrodes need different lithium supplement amounts. By adjusting the parameters of the rolling process, the thickness of the lithium strip body 200 can be changed, and the number and size of the first gap 210, the second gap 220 and the lithium strip 230 can be changed, so that the proportion of the metal lithium in the lithium strip body 200 is changed, and the lithium supplement amount can be accurately controlled for different silicon-doped negative electrodes.
In other embodiments, the lithium ribbon body 200 may be obtained by other processing methods, for example, the lithium ribbon body 200 may be obtained by laser etching or the like.
With continued reference to fig. 1, in some embodiments, the lithium ribbon body 200 has a first direction a and a second direction B perpendicular to each other, and each lithium ribbon strip 230 extends along the second direction B.
The first direction a is perpendicular to the axial direction of the work rolls during rolling. The lithium metal foil is asynchronously rolled and then discharged along a first direction a, and due to the shearing force during rolling, the lithium strip 230 is formed into a long strip shape along a direction perpendicular to the first direction a, wherein the direction perpendicular to the first direction a is referred to as a second direction B.
The length of the negative electrode in the coiled lithium ion battery is far greater than the width of the negative electrode, and in order to facilitate the pressing of the metal lithium strip and the silicon-doped negative electrode, the substrate 100 is also arranged into a rectangle with the length far greater than the width. With continued reference to fig. 1, the dimension of the substrate 100 along the first direction a is referred to as the substrate length L, and the dimension of the substrate 100 along the second direction B is referred to as the substrate width W. When the lithium ribbon body 200 is transferred to the substrate 100, the extending direction of the lithium ribbon strip 230 is consistent with the width W of the substrate 100, so that the lithium ribbon body 200 and the substrate 100 form a metal lithium ribbon with a length much greater than a width rectangle.
When the lithium ribbon body 200 is transferred to the silicon-doped negative electrode through the substrate 100, the length L of the substrate 100 is consistent with the length of the silicon-doped negative electrode, and the width W of the substrate 100 is consistent with the width of the silicon-doped negative electrode, so that a lithium ribbon with metal as little as possible can be laid along the width of the silicon-doped negative electrode and the length of the silicon-doped negative electrode, and the operation process is simplified.
With continued reference to fig. 1, in the present embodiment, the size of the lithium strips 230 along the first direction a is 100 μm-1500 μm;
and/or, the size of the lithium ribbon 230 in the second direction B is greater than or equal to 2 mm.
Specifically, when the lithium ribbon width W1 is less than 100 μm, the volume fraction of the lithium ribbon 100 in the lithium ribbon body 200 is small, the thickness of the lithium ribbon body 200 is also reduced, the surface capacity of the metal lithium ribbon is low, the amount of lithium ions consumed during first charge and discharge cannot be supplemented, and the effect of improving the first effect cannot be achieved. When the width W1 of the lithium ribbon is greater than 1500 μm, the thickness of the lithium ribbon body 200 increases, and an excessive amount of lithium replenishment may occur.
The size of the lithium ribbon 230 in the second direction B is referred to as a lithium ribbon length L1, and when the lithium ribbon length L1 is less than 2mm, the volume fraction of the lithium ribbon 230 in the lithium ribbon body 200 is small, the thickness of the lithium ribbon body 200 is also reduced, the surface capacity of the metal lithium ribbon is low, the amount of lithium ions consumed during first charge and discharge cannot be supplemented, and the effect of improving the first effect cannot be achieved.
As shown in fig. 1, the first gaps 210 and the lithium stripe 230 are spaced along a first direction a, which is perpendicular to the extending direction of the lithium stripe 230.
The lithium metal foil is asynchronously rolled and then discharged along the first direction A, and due to the action of shearing force during rolling, a structure that the first gap 210 and the lithium strips 230 are arranged at intervals along the first direction A is formed. The first gaps 210 and the lithium ribbon strips 230 are arranged at intervals, so that the lithium ribbon strips 230 are uniformly distributed, and uniform lithium supplement of the silicon-doped negative electrode can be realized.
The first gap 210 is a long hole, and the long axis direction of the first gap 210 is the same as the second direction B.
As shown in fig. 1, the first gap 210 may be a substantially regular rectangle, and the length direction of the rectangle is consistent with the extending direction of the lithium stripe 230, that is, consistent with the second direction B. The first gap 210 may also be an irregular elongated hole having a major axis and a minor axis, both of which are arc-shaped, and the elongated hole may extend in a direction generally identical to the extending direction of the lithium ribbon 230. The specific shape of the first gap 210 may vary depending on the rolling parameters.
In the present application, the width of the first gap 230 is less than or equal to 1500 μm.
The metal lithium is a soft metal, and the formation of the lithium ribbon body 200 is not facilitated when the width of the first gap 210 is too large. In a specific implementation, the width of the first gap 210 is less than or equal to 1500 μm, which satisfies the requirement of the electrolyte flowing to wet the lithium ribbon body 200 and the silicon-doped negative electrode.
The second gaps 220 and the lithium stripe strips 230 are spaced apart in the second direction B.
The second direction B coincides with the axial direction of the work rolls at the time of rolling. The lithium ribbon strips adjacent to each other along the second direction B have a second gap 220 therebetween, and a portion of the first gap 210 is communicated with the second gap 220 to facilitate the electrolyte to flow to infiltrate the lithium ribbon body 200 and the silicon-doped negative electrode.
As shown in fig. 2, the lithium metal tape further includes a release agent layer 300, and the substrate 100, the release agent layer 300 and the lithium tape body 200 are sequentially stacked.
When the silicon-doped negative electrode is used for lithium supplement, after the lithium ribbon body 200 and the silicon-doped negative electrode are pressed, in order to facilitate peeling off the substrate 100, a release agent layer 300 may be coated between the substrate 100 and the lithium ribbon body 200.
Specifically, cut into suitable size with substrate 100 as required, coat release agent layer 300 on substrate 100, lay lithium belt body 200 on release agent layer 300, substrate 100, release agent layer 300 and lithium belt body 200 stack gradually the setting, set up release agent layer 300 and can make substrate 100 be convenient for peel off from lithium belt body. In the present embodiment, the release agent layer 300 may be a silicone release agent layer.
The invention also provides a negative plate which comprises a negative current collector, an active substance layer and the metal lithium strip provided by the embodiment, wherein the active substance layer is coated on the negative current collector, and the metal lithium strip is pressed on the active substance layer.
The structure of the metal lithium ribbon is described in detail in the above embodiments, and is not described in detail here.
When the negative plate is manufactured, the active substance layer is coated on the negative current collector, and then the metal lithium belt is transferred to the surface of the silicon-doped negative electrode. Specifically, one surface of the lithium ribbon body 200 in the metal lithium ribbon is in contact with the active material layer, a certain load is applied to the metal lithium ribbon and the negative plate to press the metal lithium ribbon and the negative plate, after the lithium ribbon body 200 and the negative plate are pressed, the substrate 100 is peeled off to complete the transfer of the lithium ribbon body 200, and the negative plate containing the lithium ribbon body 200 is formed.
Lithium ions in the lithium ribbon body 200 laminated on the active material layer are inserted into the negative electrode through the following two processes. The first process is that a small part of lithium ions enter the active material layer by means of solid-phase intercalation before the electrolyte is injected. And the second process is that after the positive plate, the diaphragm and the negative plate are wound into a battery cell and electrolyte is injected, most of the remaining lithium ions are embedded into the active material layer through the infiltration of the electrolyte in the aging process, and the lithium supplement of the negative plate is completed.
In this embodiment, the active material layer is a silicon-doped active material layer, and the content of silicon in the silicon-doped active material layer is less than or equal to 30%.
The theoretical specific capacity of the silicon material is usually more than 4200mAh/g, the theoretical specific capacity of the graphite is 372mAh/g, and the theoretical specific capacity of the silicon material is far higher than that of the graphite, so that the silicon material is an ideal substitute material of the graphite. Silicon is added into the active material layer to form a silicon-doped active material layer, so that the specific capacity of the lithium ion battery can be improved.
Because the cycle performance of the lithium ion battery is affected by the overlarge volume expansion after lithium ions are inserted into the pure silicon material, the silicon content in the silicon-doped active material layer is less than or equal to 30 percent.
The invention also provides a battery, a positive plate, a diaphragm and the negative plate provided by the embodiment, wherein the diaphragm is positioned between the positive plate and the negative plate.
The structure of the negative electrode plate is described in detail in the above embodiments, and is not described in detail here.
The positive plate and the negative plate are core components of the battery and are respectively used as a positive electrode and a negative electrode of the battery. The diaphragm plays the role of electronic insulation and lithium ion migration micropore channel between the positive plate and the negative plate. When the battery is assembled, the separator is placed between the positive electrode sheet and the negative electrode sheet, and is laminated and wound to form a battery cell. And (4) putting the battery core into the shell, and injecting electrolyte to finally form the battery.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A lithium metal ribbon is characterized by comprising a substrate and a lithium ribbon body, wherein the lithium ribbon body is arranged on the substrate, the lithium ribbon body is provided with a plurality of first gaps and a plurality of second gaps so as to divide the lithium ribbon body into a plurality of lithium ribbon strips, and included angles are formed between the first gaps and the second gaps.
2. The lithium metal ribbon of claim 1, wherein the thickness of the lithium ribbon body is greater than or equal to 1 μ ι η and less than or equal to 10 μ ι η.
3. The lithium metal ribbon of claim 1, wherein the bulk of the lithium ribbon has an areal density of 0.1mg/cm or greater2And is less than or equal to 0.4mg/cm2。
4. The lithium metal ribbon of claim 1, wherein the lithium ribbon body has a first direction and a second direction that are perpendicular to each other, each lithium ribbon strip extending in the second direction.
5. The lithium metal ribbon of claim 4, wherein the lithium ribbon has a dimension along the first direction of 100 μ ι η to 1500 μ ι η;
and/or the dimension of the lithium tape strip in the second direction is greater than or equal to 2 mm.
6. The lithium metal ribbon of claim 1, wherein the width of the first gap is less than or equal to 1500 μ ι η.
7. The metallic lithium ribbon of any one of claims 1 to 6, further comprising a release agent layer, wherein the substrate, the release agent layer, and the lithium ribbon body are sequentially stacked.
8. A negative electrode sheet comprising a negative electrode current collector, an active material layer coated on the negative electrode current collector, and the metallic lithium ribbon of any one of claims 1 to 7, wherein the metallic lithium ribbon is laminated on the active material layer.
9. The negative electrode sheet of claim 8, wherein the active material layer is a silicon-doped active material layer, and the silicon content in the silicon-doped active material layer is less than or equal to 30%.
10. A battery comprising a positive electrode sheet, a separator and the negative electrode sheet according to claim 8 or 9, wherein the separator is located between the positive electrode sheet and the negative electrode sheet.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116371701A (en) * | 2023-04-26 | 2023-07-04 | 蜂巢能源科技股份有限公司 | Process and device for pre-oiling lithium calendering |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1177417A (en) * | 1995-03-06 | 1998-03-25 | 富士摄影胶片株式会社 | Nonaqueous secondary cell |
| JPH10302839A (en) * | 1997-04-25 | 1998-11-13 | Japan Storage Battery Co Ltd | Nonaqueous electrolyte secondary battery, its separator, and their manufacture |
| CN207952214U (en) * | 2018-02-27 | 2018-10-12 | 中航锂电技术研究院有限公司 | Lithium foil formation system |
| CN109256521A (en) * | 2017-07-12 | 2019-01-22 | 宁德时代新能源科技股份有限公司 | Calendering device |
| CN210123779U (en) * | 2019-06-28 | 2020-03-03 | 天津中能锂业有限公司 | Through-hole lithium film prefabricated part, composite negative electrode and energy storage device |
| CN111384405A (en) * | 2018-12-28 | 2020-07-07 | 宁德时代新能源科技股份有限公司 | Electrode assembly and lithium ion battery |
| WO2021027782A1 (en) * | 2019-08-05 | 2021-02-18 | 宁德时代新能源科技股份有限公司 | Lithium-supplementing negative electrode sheet, preparation method therefor, and lithium ion battery, battery module, battery pack and device related thereto |
| CN214411247U (en) * | 2021-04-26 | 2021-10-15 | 宁德时代新能源科技股份有限公司 | Lithium supplementing device |
| CN113823760A (en) * | 2020-06-18 | 2021-12-21 | 天津中能锂业有限公司 | Ultrathin lithium strip prefabricated member, composite negative electrode, preparation method of composite negative electrode and battery |
-
2021
- 2021-12-31 CN CN202111679800.7A patent/CN114335432A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1177417A (en) * | 1995-03-06 | 1998-03-25 | 富士摄影胶片株式会社 | Nonaqueous secondary cell |
| JPH10302839A (en) * | 1997-04-25 | 1998-11-13 | Japan Storage Battery Co Ltd | Nonaqueous electrolyte secondary battery, its separator, and their manufacture |
| CN109256521A (en) * | 2017-07-12 | 2019-01-22 | 宁德时代新能源科技股份有限公司 | Calendering device |
| CN207952214U (en) * | 2018-02-27 | 2018-10-12 | 中航锂电技术研究院有限公司 | Lithium foil formation system |
| CN111384405A (en) * | 2018-12-28 | 2020-07-07 | 宁德时代新能源科技股份有限公司 | Electrode assembly and lithium ion battery |
| CN210123779U (en) * | 2019-06-28 | 2020-03-03 | 天津中能锂业有限公司 | Through-hole lithium film prefabricated part, composite negative electrode and energy storage device |
| WO2021027782A1 (en) * | 2019-08-05 | 2021-02-18 | 宁德时代新能源科技股份有限公司 | Lithium-supplementing negative electrode sheet, preparation method therefor, and lithium ion battery, battery module, battery pack and device related thereto |
| CN113823760A (en) * | 2020-06-18 | 2021-12-21 | 天津中能锂业有限公司 | Ultrathin lithium strip prefabricated member, composite negative electrode, preparation method of composite negative electrode and battery |
| CN214411247U (en) * | 2021-04-26 | 2021-10-15 | 宁德时代新能源科技股份有限公司 | Lithium supplementing device |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116371701A (en) * | 2023-04-26 | 2023-07-04 | 蜂巢能源科技股份有限公司 | Process and device for pre-oiling lithium calendering |
| CN116371701B (en) * | 2023-04-26 | 2024-03-22 | 蜂巢能源科技股份有限公司 | Process and device for pre-oiling lithium calendering |
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