CN216389432U - Pole piece and battery cell - Google Patents
Pole piece and battery cell Download PDFInfo
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- CN216389432U CN216389432U CN202122977735.8U CN202122977735U CN216389432U CN 216389432 U CN216389432 U CN 216389432U CN 202122977735 U CN202122977735 U CN 202122977735U CN 216389432 U CN216389432 U CN 216389432U
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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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Abstract
The utility model provides a pole piece and a battery cell, wherein the pole piece comprises a current collector, the current collector comprises a paste coating area and a hollow foil area which are sequentially arranged along the width direction, and the paste coating area is provided with an active substance layer; the empty foil area comprises a glue-free area and a glue-sticking area, wherein the glue-free area and the glue-sticking area are sequentially arranged along the width direction, and the glue-sticking area is arranged on one side close to the paste coating area. The utility model can effectively avoid the problems of potential safety hazard and influence on the storage performance and the cycle performance of the battery caused by the deformation of the aluminum plastic film shell arranged outside.
Description
Technical Field
The utility model relates to the technical field of lithium ion batteries, in particular to a pole piece and a battery cell.
Background
Soft packet of lithium ion battery is according to the whole utmost point ear structure classification of internal battery, can divide into unipolar ear winding structure, many utmost points ear winding structure and whole utmost point ear winding structure, and whole utmost point ear winding structure is because advantages such as with low costs, multiplying power performance are good, is prepared in market favor.
The general welding mode is perpendicular to the plane direction of the empty foil, and the empty foil is welded together from top to bottom in sequence, but the thickness of the empty foil is large, so that the phenomenon of insufficient welding or broken welding of the tab is easy to occur due to the fact that welding energy is difficult to control in the tab welding process, and welding is not firm. In addition, the single-pole lug and the multi-pole lug can bend the lugs, and after the lugs are welded with a winding core, a small space (0.2mm to 3mm) is reserved between a winding core diaphragm and the aluminum-plastic film for top sealing; and the full utmost point ear winding structure has the empty paper tinsel because the corner exists, can not buckle to empty paper tinsel after the utmost point ear welding, just, the welding is carried out after the empty paper tinsel of 7mm to 12mm needs to be reserved at negative pole utmost point ear both ends, need reserve 7mm to 12mm space between diaphragm and the plastic-aluminum membrane promptly and be used for placing empty paper tinsel. However, the thickness of the empty foil area is smaller than that of the winding core, so that the winding core is not flat, and after subsequent liquid injection, vacuum adsorption and formation, secondary vacuum pumping and the like are performed, so that the aluminum plastic film at the position of 7mm to 12mm is deformed. The deformed aluminum-plastic film affects the appearance of the battery, the appearance of the battery is poor, the deformed aluminum-plastic film has a positive pressure on the edges of the positive and negative pole pieces and the diaphragm, the edges of the positive and negative pole pieces and the diaphragm are subjected to uneven external force, the polarization of the positive and negative pole materials is severe after long-time circulation, the expansion deformation of the pole pieces is obvious, the powder falling at the position after the battery is disassembled is severe, the self-discharge is large, and the service life of the battery is shortened; in addition, uneven external force is applied to the position after expansion deformation, the diaphragm is easy to pierce, the short circuit probability is increased, and serious potential safety hazards exist.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the problem that the safety performance and the working performance of a battery are influenced because an aluminum plastic film is deformed due to the fact that a battery core of a full-lug structure is not flat.
In order to solve the above problems, a first aspect of the present invention provides a pole piece, including a current collector, where the current collector includes a paste applying region and a blank foil region sequentially arranged along a width direction, and the paste applying region is provided with an active material layer;
the empty foil area comprises a glue-free area and a glue-sticking area, wherein the glue-free area and the glue-sticking area are sequentially arranged along the width direction, and the glue-sticking area is arranged on one side close to the paste coating area.
Further, the thickness of the adhesive area is the same as that of the paste coating area.
Further, the length of the gummed paper is not more than the length of the empty foil area.
Further, the adhesive paper is arranged on one side surface or two side surfaces of the empty foil area.
Furthermore, the adhesive tape comprises an adhesive layer and a substrate layer, wherein the substrate layer is clamped between the two adhesive layers, and the adhesive layer comprises at least one of water glue, oil glue, hot melt glue, natural rubber, synthetic rubber and conductive swelling glue.
Further, the distance between the gummed paper arranged on the gumming area and the paste coating area is 0-0.5 mm.
According to the pole piece, the adhesive paper is arranged on the empty foil area of the pole piece, and the empty foil area after the adhesive paper is pasted has a certain thickness, so that the thickness difference between the empty foil area and the paste coating area can be reduced or eliminated, the surface of the battery cell prepared by winding or laminating the pole piece can be smoother, the problem that the flatness of the surface of the battery cell is poor due to the large thickness difference between the whole lug plane and the whole battery cell is solved, and the problems that potential safety hazards are generated and the storage performance and the cycle performance of the battery are affected due to the deformation of an aluminum-plastic film shell arranged outside can be effectively avoided; in addition, one side edge of the pole piece is a glue-free area without adhesive paper, so that a thin welding surface is formed after the subsequent electric core is subjected to rubbing treatment, the welding difficulty is reduced, the welding success rate is improved, and the welding firmness is also improved.
The second aspect of the utility model provides a battery cell, which comprises a first pole piece, a second pole piece and a diaphragm arranged between the first pole piece and the second pole piece, wherein the polarities of the first pole piece and the second pole piece are opposite;
the first pole piece and the second pole piece are both the pole pieces described in any one of the first aspect.
Further, the first pole piece, the diaphragm and the second pole piece are wound in an overlapping mode or overlapped alternately along the length direction of the first pole piece and the second pole piece to form the battery cell;
the paste coating area of the first pole piece and the paste coating area of the second pole piece are arranged in an overlapping mode, the empty foil area of the first pole piece and the empty foil area of the second pole piece are respectively arranged at two ends, opposite to each other, of the battery cell in the width direction, and the adhesive tape is continuously arranged between the adhesive tape area of the first pole piece and the adhesive tape area of the second pole piece.
Furthermore, the two glue-free areas are respectively located at two ends of the battery cell in the width direction, and each glue-free area forms a welding surface on the side surface of the glue-sticking area.
Furthermore, the battery cell further comprises connecting pieces, and the two connecting pieces are respectively welded on the welding surfaces at the two ends of the battery cell.
According to the battery core, the adhesive paper is arranged on the empty foil area of the pole piece, and the empty foil area after the adhesive paper is pasted has a certain thickness, so that the thickness difference between the empty foil area and the paste coating area can be reduced or eliminated, the surface of the battery core prepared by winding or laminating the pole piece can be smoother, the problem that the flatness of the surface of the battery core is poor due to the large thickness difference between the whole pole lug plane and the whole battery core is solved, and the problems that potential safety hazards are generated and the storage performance and the cycle performance of the battery are affected due to the deformation of an aluminum-plastic film shell arranged outside can be effectively avoided; the battery cell formed by overlapping and winding or alternately overlapping the first pole piece and the second pole piece can be fixed into a whole by arranging the adhesive tape in the empty foil area of the pole pieces, so that the whole battery cell can be connected more tightly, and the battery cell is prevented from loosening to influence the performance of the battery cell; in addition, one side edge of the pole piece is a glue-free area without adhesive paper, so that a thin welding surface is formed after the subsequent electric core is subjected to rubbing treatment, the welding difficulty is reduced, the welding success rate is improved, and the welding firmness is also improved.
Drawings
Fig. 1 is a schematic structural diagram of a battery cell with adhesive tape arranged on a single-side surface thereof in an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a battery cell with adhesive tapes on surfaces on both sides in the embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a first pole piece according to an embodiment of the present disclosure;
FIG. 4 is a schematic structural diagram of a second pole piece according to an embodiment of the present disclosure;
fig. 5 is a schematic view of a front view structure of a battery cell in an embodiment of the utility model
Fig. 6 is a schematic perspective structure diagram of a battery cell formed by winding in the embodiment of the present invention;
fig. 7 is a graph showing a cycle comparison of three batteries according to an embodiment of the present invention.
Description of reference numerals:
1-a first current collector; 2-pasting area; 3-a first empty foil zone; 4-a second current collector; 5-a second empty foil area; 6-a separator; 7-gummed paper; 8-a first connecting tab; 9-a second connecting sheet;
21-first pasting area; 22-second pasting area; 31-a first adhesive area; 32-a first glue-free zone; 51-a second adhesive area; 52-second glue free zone.
Detailed Description
The technical scheme of the utility model is clearly and thoroughly described in the following with reference to the accompanying drawings. In the description of the present invention, it should be noted that, in the coordinate system XY provided herein, the X axis represents the length direction, and the Y axis represents the width direction. Also, it is noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing and simplifying the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the utility model.
In the description of the present specification, the description of the term "on the basis of the above-described embodiments" means that a specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one preferred embodiment or preferred example of the present invention. Throughout this specification, the schematic representations of the terms used above do not necessarily refer to the same implementation or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
In order to further illustrate the present invention, the following examples are given to further illustrate the present invention.
The first aspect of the embodiments of the present invention provides a pole piece, which includes a current collector, the current collector includes a paste coating area and a blank foil area, which are sequentially arranged along a width direction, the paste coating area is provided with an active material layer, and the blank foil area is not provided with an active material layer;
the empty foil area comprises a glue-free area and a rubberizing area which are arranged along the width direction, no gummed paper is arranged in the glue-free area, gumming paper is arranged in the rubberizing area, and the rubberizing area is arranged on one side close to the paste coating area.
The pole pieces comprise a first pole piece and a second pole piece, the first pole piece and the second pole piece are both the pole pieces, the polarities of the first pole piece and the second pole piece are opposite, and the first pole piece can be a positive pole piece or a negative pole piece; correspondingly, the second pole piece is a negative pole piece or a positive pole piece. The active material layers arranged on the paste coating areas of the first pole piece and the second pole piece are different, if the first pole piece is a positive pole piece, the first active material layer arranged on the paste coating area of the first pole piece is a positive active material layer, and if the first pole piece is a negative pole piece, the first active material layer arranged on the paste coating area of the first pole piece is a negative active material layer; correspondingly, if the second pole piece is a negative pole piece, the second active material layer arranged in the paste coating area of the second pole piece is a negative pole active material layer, and if the second pole piece is a positive pole piece, the second active material layer arranged in the paste coating area of the second pole piece is a positive pole active material layer.
Specifically, referring to fig. 1 to 3, the first electrode sheet includes a first current collector 1, the first current collector 1 includes a first paste applying region 21 provided with a first active material layer (not labeled in the figures) and a first empty foil region 3 provided with no first active material layer, and the first paste applying region 21 and the first empty foil region 3 are sequentially arranged along a width direction of the first current collector 1; the first empty foil area 3 comprises a first adhesive-free area and a first adhesive-pasting area (marked in the figure) which are arranged along the width direction, the adhesive paper 7 is not arranged in the first adhesive-free area, the adhesive paper 7 is arranged in the first adhesive-pasting area, and the first adhesive-pasting area is arranged on one side close to the first paste-coating area 21.
As shown in fig. 1, fig. 2 and fig. 4, the second electrode sheet includes a second current collector 4, the second current collector 4 includes a second paste area 22 provided with a second active material layer (not shown in the figures) and a second empty foil area 5 provided with no second active material layer, and the second paste area 22 and the second empty foil area 5 are sequentially arranged along the width direction of the second current collector 4; the second empty foil area 5 includes a second non-adhesive area and a second adhesive area (both marked in the figure) arranged along the width direction, the second non-adhesive area is not provided with adhesive paper 7, the second adhesive area is provided with adhesive paper 7, and the second adhesive area is arranged on one side close to the second pasting area 22.
In the embodiment of the utility model, the adhesive paper is arranged on the empty foil area of the pole piece, and the empty foil area after being pasted with the adhesive paper has a certain thickness, so that the thickness difference between the empty foil area and the paste coating area can be reduced or eliminated, the surface of the battery cell prepared by winding or laminating the pole piece can be smoother, and the problem of poor flatness of the surface of the battery cell due to the large thickness difference between the whole pole lug plane and the whole battery cell is solved, so that the problems of potential safety hazard and influence on the storage performance and the cycle performance of the battery due to the deformation of an external aluminum-plastic film shell can be effectively avoided; in addition, one side edge of the pole piece is a glue-free area without adhesive paper, so that a thin welding surface is formed after the subsequent electric core is subjected to rubbing treatment, the welding difficulty is reduced, the welding success rate is improved, and the welding firmness is also improved.
On the basis of the above embodiment, the thickness of the first pasting region is the same as that of the first pasting region 21, and the thickness of the second pasting region is the same as that of the second pasting region 22, so that the thickness of the first empty foil region 3 and the thickness of the first pasting region 21 after pasting the adhesive paper are the same, and the thickness of the second empty foil region 5 and the thickness of the second pasting region 22 are the same, so that the thickness of the surface of the battery cell made by winding or laminating the first pole piece and the second pole piece is the same, the surface of the battery cell is kept flat, the problem of uneven surface of the battery cell due to the fact that the thickness of the whole pole lug plane is not the same as that of the whole battery cell is avoided, the surface of the external aluminum-plastic film shell is also guaranteed to be flat, and the aluminum-plastic film shell is prevented from deforming.
In this embodiment, the first current collector 1 and the second current collector 4 are one or more metal foils such as an aluminum foil, a copper foil, a nickel foil, a gold foil, or a platinum foil, and preferably, the first current collector 1 is an aluminum foil, and the second current collector 4 is a copper foil.
The length of the adhesive paper 7 is not greater than the lengths of the first and second empty foil areas 3 and 5, that is, the length of the adhesive paper 7 is less than or equal to the lengths of the first and second empty foil areas 3 and 5, the adhesive paper 7 may be continuously disposed on the first and/or second empty foil areas 3 and 5, or may be disposed on the first and/or second empty foil areas 3 and 5 in sections, that is, the adhesive paper 7 is disposed at intervals along the length direction in the first adhesive area of the first empty foil area 3, and the area where the adhesive paper 7 is not disposed is located between the two adhesive papers 7, and/or the adhesive paper 7 is disposed at intervals along the length direction in the second adhesive area of the second empty foil area 5, and the area where the adhesive paper 7 is not disposed is located between the two adhesive papers 7. The embodiment of the present invention does not further limit this, as long as it can ensure that the length of the adhesive paper 7 is not greater than the lengths of the first and second empty foil regions 3 and 5, and that the thickness of the first adhesive region is the same as the thickness of the first pasting region 21, and the thickness of the second adhesive region is the same as the thickness of the second pasting region 22.
The adhesive paper 7 is arranged on one side surface of the first empty foil area 3 or the adhesive paper 7 is arranged on two side surfaces of the first empty foil area 3, the adhesive paper 7 is arranged on one side surface or two side surfaces of the first empty foil area 3 and is related to the first active material layer arranged on one side surface or two side surfaces of the first paste coating area 21, if the first active material layer is arranged on one side surface of the first paste coating area 21, the adhesive paper 7 is arranged on one side surface of the first empty foil area 3; if the first paste applying region 21 is provided with the first active material layer on both surfaces, the adhesive sheet 7 is provided on both surfaces of the first empty foil region 3.
The adhesive paper 7 is arranged on one side surface of the second empty foil area 5 or the adhesive paper 7 is arranged on both side surfaces of the second empty foil area 5, the adhesive paper 7 is arranged on one side surface or both side surfaces of the second empty foil area 5 and is related to the second active material layer arranged on one side surface or both side surfaces of the second paste coating area 22, if the second active material layer is arranged on one side surface of the second paste coating area 22, the adhesive paper 7 is arranged on one side surface of the second empty foil area 5; if the second paste applying region 22 is provided with the second active material layer on both surfaces, the adhesive sheet 7 is provided on both surfaces of the second empty foil region 5.
The adhesive paper 7 is disposed on one side surface or both side surfaces of the first and second empty foil areas 3 and 5 in this embodiment, which is not further limited, and may be set by those skilled in the art according to the actual situation, but generally, the efficiency of disposing the adhesive paper 7 on one side surface of the first and second empty foil areas 3 and 5 is higher than the efficiency of disposing the adhesive paper 7 on both side surfaces of the first and second empty foil areas 3 and 5.
Wherein, the material of the adhesive layer comprises at least one of water glue, oil glue, hot melt adhesive, natural rubber, synthetic rubber and conductive swelling glue. On the basis of the above embodiment, the material of the adhesive layer includes conductive swelling glue.
The conductive swelling glue has good swelling performance (the volume expansion rate of the conductive swelling glue soaked in the electrolyte at 25 ℃ for 24 hours is more than or equal to 100%) and conductivity (the conductivity is more than or equal to 10)4S/m) of the adhesive. The electric core can be fixed by the conductive swelling glue, the electric core is not loose, the conductive swelling glue has a swelling function in the electrolyte, in the process of recycling the electric core, the conductive swelling glue can move relatively along with the volume expansion of the electric core, the conductive swelling glue is always tightly attached to the first empty foil area 3 and the second empty foil area 5, the constant expansion effect can be achieved according to the thickness of the electric core and the volume of the electrolyte, and the situation that the volume expansion of the electric core causes constant expansion is effectively avoidedThe phenomenon that the welding points between the first empty foil areas 3 and between the second empty foil areas 5 are broken or fall off; in addition, the conductive swelling glue has conductive performance, so that the propagation path of lithium ions can be shortened, the internal resistance of the battery is reduced, and the rate capability of the battery is enhanced.
Specifically, the conductive swelling glue comprises a swelling component and a conductive component, wherein the swelling component can expand in volume in the presence of electrolyte, and can be effectively filled between the first rubberizing areas of the first hollow foil area 3 and the first rubberizing areas of the second hollow foil area 5, so that the thicknesses of all positions of the battery core are consistent, the conductive swelling glue can be ensured to have conductive performance, and the influence of an adhesive layer on the internal resistance of the battery is avoided.
Wherein the swelling component is at least one of polyurethane acrylate, epoxy acrylate and polyester acrylate. The swelling component has a proper volume expansion rate in the electrolyte and a certain conductive function, and after being compounded with the conductive component, the conductivity of the conductive swelling adhesive can be better improved, and the internal resistance of the battery is reduced.
The conductive component is at least one of an organic conductive component, metal powder and graphite powder, wherein the organic conductive component comprises at least one of epoxy resin, organic silicon resin, polyimide resin, phenolic resin, polyurethane and acrylic resin; the metal powder includes at least one of copper, aluminum, iron, nickel, zinc, silver, and gold.
In this embodiment, the mixing ratio of the swelling component and the conductive component in the conductive swelling adhesive is not further limited, and a person skilled in the art can mix the swelling component and the conductive component according to a specific lithium ion battery electrolyte, as long as the conductive swelling adhesive has good swelling performance and conductivity.
In this embodiment, the material of the substrate layer is not further limited, and those skilled in the art can select the substrate according to actual situations as long as the substrate can provide better support, and for example, the material of the substrate layer is at least one of cast polypropylene, uniaxially stretched polypropylene, biaxially stretched polypropylene, polyethylene, polyester fiber, and polyvinyl chloride.
The thickness of the adhesive tape 7 is not further limited in this embodiment, as long as it can be ensured that the thickness of the adhesive tape 7 is the same as that of the first active material layer, the thickness of the adhesive tape 7 is the same as that of the second active material layer, so that the thickness of the first pole piece at the first adhesive region is the same as that of the first paste region 21, and the thickness of the second pole piece at the second adhesive region is the same as that of the second paste region 22. However, in order to make the conductive swelling paste exert its swelling action and conductive action well, on the substrate of the above embodiment, the thickness of both adhesive layers is 1 μm to 3 μm, and more preferably, the thickness of both adhesive layers is 2 μm; the thickness of the substrate layer can be set according to actual conditions.
The distance between the adhesive tape 7 arranged on the first adhesive tape pasting area and the first paste coating area 21 is 0-0.5 mm, and the distance between the adhesive tape 7 arranged on the second adhesive tape pasting area and the second paste coating area 22 is 0-0.5 mm, so that the adhesive tape 7 can be prevented from overlapping with the first paste coating area 21 and the second paste coating area 22 to influence the thickness of the first pole piece and the second pole piece.
With reference to fig. 1 to 6, a second aspect of the embodiment of the present invention provides a battery cell, including: the diaphragm comprises a first pole piece, a second pole piece and a diaphragm 6 arranged between the first pole piece and the second pole piece, wherein the polarities of the first pole piece and the second pole piece are opposite, and the first pole piece and the second pole piece are both pole pieces of the first aspect.
In the battery core provided by the embodiment, the adhesive tapes are respectively arranged in the first empty foil area and the second empty foil area, the thickness of the first empty foil area after the adhesive tapes are pasted is the same as that of the first paste coating area, and the thickness of the second empty foil area after the adhesive tapes are pasted is the same as that of the second paste coating area, so that the thickness difference between the first empty foil area and the first paste coating area and the thickness difference between the second empty foil area and the second paste coating area can be reduced or eliminated, the surface of the battery core made by winding or laminating the pole pieces can be smoother, the problem that the flatness of the surface of the battery core is poor due to the large thickness difference between the whole pole lug plane and the whole battery core is solved, and therefore, the problems that the potential safety hazard is generated and the storage performance and the cycle performance of the battery are affected due to the deformation of an aluminum plastic film shell arranged outside can be effectively avoided; the battery cell formed by overlapping and winding or alternately overlapping the first pole piece and the second pole piece can be fixed into a whole by arranging the adhesive tape in the empty foil area of the pole pieces, so that the whole battery cell can be connected more tightly, and the battery cell is prevented from loosening to influence the performance of the battery cell; in addition, one side edge of the pole piece is a glue-free area without adhesive paper, so that a thin welding surface is formed after the subsequent electric core is subjected to rubbing treatment, the welding difficulty is reduced, the welding success rate is improved, and the welding firmness is also improved.
Specifically, the first pole piece, the second pole piece and the diaphragm 6 may be stacked and wound to form a cell, or the first pole piece, the second pole piece and the diaphragm 6 may be stacked alternately to form a cell, no matter which way the cell is formed, so as to avoid short circuit caused by contact between the positive electrode tab and the negative electrode tab during welding, on the basis of the above embodiment, the first paste applying region 21 and the second paste applying region 22 are overlapped to form the paste applying region 2, and the first empty foil region 3 and the second empty foil region 5 are respectively disposed at two opposite ends of the paste applying region 2.
Wherein, the adhesive tape 7 sets up between first rubberizing district and second rubberizing district in succession, promptly, the adhesive tape 7 sets up between first rubberizing district in succession, and the adhesive tape 7 sets up between the second rubberizing district in succession, and scribbles the both sides of the adhesive tape 7 of cream district 2 one end and be first rubberizing district, scribble the both sides of the adhesive tape 7 of the other end of cream district 2 and be the second rubberizing district.
After the first pole piece, the second pole piece and the diaphragm 6 are stacked and wound or alternately stacked to form the battery core, the first empty foil area 3 and the second empty foil area 5 need to be flattened, and the flattening process is to press down the originally vertical first empty foil area 3 and the second empty foil area 5, so that the first empty foil area 3 and the second empty foil area 5 of each stacked and wound or alternately stacked layer are mutually contacted, on one hand, a connecting sheet can be better welded, and on the other hand, a better current collecting effect can be achieved. In order to avoid the influence of the gummed paper 7 on the flow concentration effect, the first empty foil area 3 and the second empty foil area 5 which are convenient to flatten can play a better flow concentration effect, a thinner welding surface can be provided after flattening is also convenient, welding is facilitated, the first glue-free area is arranged on the first empty foil area 3 of the first pole piece, and the second glue-free area is arranged on the second empty foil area 5 of the second pole piece, so that subsequent flattening treatment is facilitated.
Specifically, as shown in fig. 6, the area of the first empty foil area 3 to which the adhesive paper 7 is attached is a first adhesive area 31, and the area of the first empty foil area 3 to which the adhesive paper 7 is not attached is a first non-adhesive area 32; the area of the second empty foil area 5 to which the gummed paper 7 is pasted is a second gummed area 51, and the area of the second empty foil area 5 to which the gummed paper 7 is not pasted is a second non-gummed area 52. When the cell is flattened, performing flattening treatment on a first adhesive-free area 32 and a second adhesive-free area 52 which are not provided with adhesive tapes 7 at two ends of the cell, wherein after the flattening treatment, the thickness of the first adhesive-free area 31 is the same as that of the paste coating area 2, the thickness of the first adhesive-free area 32 is smaller than that of the first adhesive-coated area 31, and a first welding surface which is perpendicular to the first adhesive-coated area 31 is formed on the side surface of the first adhesive-free area 31 after the first adhesive-free area 32 is flattened; similarly, the thickness of the second adhesive region 51 is the same as that of the paste applying region 2, the thickness of the second adhesive-free region 52 is smaller than that of the second adhesive region 51, and a second bonding surface perpendicular to the second adhesive region 51 is formed on the side surface of the second adhesive region 51 after the second adhesive-free region 52 is flattened. First face of weld and second face of weld set up at the relative both ends of electric core, and first face of weld and second face of weld are regarded as two faces of weld of electric core respectively for the welding connection piece. From this, handle through rubbing the level and form two weld faces at the both ends of electric core, need welded number of piles when can reducing laser welding, the distance that the energy needs the transmission shortens, has reduced the welded degree of difficulty, has improved welded success rate greatly, has also improved the firm degree of welded, also can avoid easily welding when the welded connection piece and wear damage pole piece and diaphragm to effectively avoid causing the self discharge risk that the little short circuit arouses.
The way of the kneading and flattening treatment in this embodiment is not further limited, and those skilled in the art can select mechanical kneading and ultrasonic kneading and flattening according to actual situations.
As shown in fig. 6, an inverted L-shaped first connecting plate 8 and an L-shaped second connecting plate 9 are further welded on the battery cell, wherein one end of the first connecting plate 8 is welded on the first welding surface, and the other end of the first connecting plate leads out the first pole piece from the battery cell to provide a contact point during charging and discharging; one end of the second connecting sheet 9 is welded on the second welding surface, and the other end of the second connecting sheet leads out the second pole piece from the battery cell to provide a contact point during charging and discharging.
In this embodiment, the shapes of the first connecting piece 8 and the second connecting piece 9 may also be rectangular, T-shaped, or the like, and the shapes of the first connecting piece 8 and the second connecting piece 9 may be the same or different, which is not further limited in this embodiment of the present invention, and those skilled in the art may select the connecting pieces according to actual situations.
It should be noted that, in the present embodiment, specific dimensions of the first connecting piece 8 and the second connecting piece 9 are not further limited, and those skilled in the art can adjust the dimensions according to actual situations; in this embodiment, the first connecting piece 8 and the second connecting piece 9 are made of metal, for example: one or more of aluminum, copper, nickel, gold or platinum.
The electric core in this embodiment still includes electrolyte and the casing that holds electric core, and the inside formation of casing holds the chamber, and electric core and electrolyte are located and hold the intracavity, and electric core and electrolyte encapsulate in the inside of casing.
The following describes, with reference to an example, a method for manufacturing a battery cell in an embodiment of the present invention, where the method for manufacturing a battery cell includes the following steps:
step S1, coating a first active material on a single-side surface of the first current collector 1 to form a first paste coating area 21 with a first active material layer, where the upper side of the first paste coating area 21 is a first empty foil area 3 without the first active material layer, and the first empty foil area 3 is a full tab of the first pole piece; coating a second active material on the surface of one side of a second current collector 4 to form a second paste coating area 22 with a second active material layer, wherein the upper side of the second paste coating area 22 is a second empty foil area 5 without the second active material layer, and the second empty foil area 5 is a full tab of a second pole piece;
step S2, attaching a gummed paper 7 on the first empty foil area 3 on the surface of one side of the first current collector 1 coated with the first active material layer to form a first gummed area 31, wherein the width of the gummed paper 7 is smaller than the width of the first empty foil area 3, the distance between the gummed paper 7 and the first paste coating area 21 is 0-0.5 mm, the thickness of the gummed paper 7 is the same as that of the first active material layer, and the area of the first empty foil area 3 not gummed paper is a first non-gummed area 32; pasting adhesive paper 7 on a second empty foil area 5 on one side surface of the second current collector 4 coated with the second active material to form a second adhesive area 51, wherein the width of the adhesive paper 7 is smaller than that of the second empty foil area 5, the distance between the adhesive paper 7 and the second paste coating area 22 is 0-0.5 mm, the thickness of the adhesive paper 7 is the same as that of the second active material layer, and the area of the second empty foil area 5 not pasted with the adhesive paper is a second adhesive-free area 52;
step S3, drying the first active material layer and the second active material layer, stacking the first pole piece, the diaphragm 6 and the second pole piece, overlapping the first paste coating area 21 and the second paste coating area 22 to form a paste coating area 2, respectively arranging the first empty foil area 3 and the second empty foil area 5 at two opposite ends of the paste coating area 2, then winding along the length direction of the first pole piece and the second pole piece to form a battery cell, winding the paste coating areas 2 together after winding, pasting the first adhesive tape area 31 at one end of the paste coating area 2 together through adhesive paper 7, and pasting the second adhesive tape area 51 at the other end of the paste coating area 2 together through adhesive paper 7;
step S4, performing kneading and flattening treatment on the first non-adhesive area 32 and the second non-adhesive area 52 which are respectively positioned at the two ends of the electric core by adopting mechanical kneading and flattening or ultrasonic kneading and flattening, and respectively forming two welding surfaces, wherein the two welding surfaces are respectively vertical to the first adhesive area 31 and the second non-adhesive area 51, and the two welding surfaces are respectively positioned at the two ends of the electric core along the width direction;
and step S5, welding the inverted L-shaped first connecting piece 8 and the L-shaped second connecting piece 9 on two welding surfaces respectively by laser welding to obtain the battery core.
The prepared battery core is subjected to the steps of packaging, shell punching, top sealing, side sealing, liquid injection, hot cold pressing, formation, clamp baking, secondary sealing, capacity grading and the like, so that the battery is obtained, the battery is a full-tab roll core soft package battery, the positive electrode and the negative electrode are symmetrically distributed at two ends of the battery, the roll core capacity of the battery is designed to be 3850mAh, and the thickness of the battery is 3.8 mm.
The effects of the battery cell in the embodiment of the present invention are described below with reference to specific tests and test effects.
Arranging three batteries with common adhesive tapes adhered to the empty foil area, wherein the adhesive layer of the common adhesive tapes is made of hot melt adhesive, and the materials are respectively referred to as a common adhesive tape group 1, a common adhesive tape group 2 and a common adhesive tape group 3 in the following;
arranging three batteries with conductive swelling gummed paper stuck in the empty foil area, wherein the material of the adhesive layer of the conductive swelling gummed paper is conductive swelling glue, and the conductive swelling gummed paper group 1, the conductive swelling gummed paper group 2 and the conductive swelling gummed paper group 3 are respectively referred to below;
three batteries without gummed paper pasted on the empty foil area are arranged, and are respectively referred to as a comparison group 1, a comparison group 2 and a comparison group 3 below.
The materials of the first pole piece and the second pole piece of the three groups of batteries and the first active material layer and the second active material layer are the same, and the winding modes of the first pole piece, the second pole piece and the diaphragm of the three groups of batteries are also the same, so that the difference is only whether the first empty foil area and the second empty foil area are pasted with adhesive paper or not and the type of the pasted adhesive paper.
After the battery is packaged for the second time, the comparison group 1, the comparison group 2 and the comparison group 3 have obvious depressions at the tab welding positions, the appearance smoothness is poor, the attractiveness is low, the common adhesive tape group 1, the common adhesive tape group 2, the common adhesive tape group 3, the conductive swelling adhesive tape group 1, the conductive swelling adhesive tape group 2 and the conductive swelling adhesive tape group 3 do not have depressions at the tab welding positions, the appearance smoothness is good, and the attractiveness is high.
In order to further verify the performances of the three groups of batteries, the three groups of batteries are subjected to a stability test and a cycle performance test respectively.
And (3) stability testing: after the battery is fully charged, the capacity retention rate and the recovery rate of the battery are tested after the battery is stored for 35 days at a high temperature of 60 ℃;
and (3) testing the stability: all three groups of batteries are charged with 3.85A current and discharged with 3.85A current, and the cycling is carried out for 400 weeks to obtain the capacity after the cycling.
After testing three groups of cells, the results shown in table 1 and fig. 7 were obtained.
Table 1 test results of each battery set
Fig. 7 is a graph comparing the cycles of three groups of cells. As can be seen from table 1 and fig. 7, after the plain adhesive tape and the conductive swelling adhesive tape are applied to the empty foil region of the battery cell for the planarization treatment, after the battery cell of the plain adhesive tape group (including the plain adhesive tape group 1, the plain adhesive tape group 2, and the plain adhesive tape group 3) and the conductive swelling adhesive tape group (including the conductive swelling adhesive tape group 1, the conductive swelling adhesive tape group 2, and the conductive swelling adhesive tape group 3) is stored at 60 ℃ in the full power state for 35 days, the capacity retention rates are all as high as 75% or more, and excellent stability is exhibited, while after the battery cell of the comparative group without the planarization treatment of the adhesive tape (including the comparative group 1, the comparative group 2, and the comparative group 3) is stored at 60 ℃ in the full power state for 35 days, the maximum value of the capacity retention rate is 10.6%, and extremely poor stability is exhibited; although the capacity recovery rates of the three groups of batteries are all more than 80%, it can be seen from fig. 7 that the capacity retention rate of the battery cell of the comparative group without the adhesive paper for the flatness treatment after 320 weeks of circulation is 80%, while the capacity retention rate of the battery cell adopting the conductive sol adhesive paper for the flatness treatment after 400 weeks of circulation is 94%, and the capacity retention rate is also obviously better than the capacity retention rate of the battery cell adopting the ordinary adhesive paper for the flatness treatment after 400 weeks of circulation, which is 92%.
From the above results, the storage performance and the cycling stability of the battery core without the adhesive paper for the leveling treatment are both worse than those of the battery core adopting the adhesive paper for the leveling treatment, because after the formation, the two vacuum air extractions are performed, the aluminum-plastic film in the empty foil area is deformed, the edges of the first pole piece, the second pole piece and the diaphragm are subjected to uneven external force exerted by the deformed aluminum-plastic film, the expansion deformation of the pole pieces is obvious after the long-time cycle, the service life of the pole pieces is reduced, the aluminum-plastic film exerts uneven external force on the positions after the expansion deformation, the diaphragm is easily punctured, and the tiny self-discharge in the battery is caused, the stored electric quantity is accumulated, and the stored electric quantity is continuously consumed, and the stability is poor; the storage performance and the circulation stability of the battery core subjected to flatness processing by adopting the conductive swelling adhesive tape are better than those of a battery subjected to flatness shaping processing by adopting common adhesive tape, because the conductive swelling adhesive can play a constant expansion effect according to the thickness of the battery core and the capacity of electrolyte after expansion, and the relative movement of pole pieces in the circulating charge-discharge process is restrained, so that the phenomenon that welding points between the first hollow foil areas and the second hollow foil areas are broken or fall off due to the volume expansion of the battery core is effectively avoided.
Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to be within the scope of the present disclosure.
Claims (10)
1. A pole piece is characterized by comprising a current collector, wherein the current collector comprises a paste coating area and a hollow foil area which are sequentially arranged along the width direction, and an active substance layer is arranged in the paste coating area;
the empty foil area comprises a glue-free area and a glue-sticking area, wherein the glue-free area and the glue-sticking area are sequentially arranged along the width direction, and the glue-sticking area is arranged on one side close to the paste coating area.
2. The pole piece of claim 1, wherein the rubberized region and the pasted region have the same thickness.
3. The pole piece of claim 1 wherein the length of the adhesive paper is no greater than the length of the empty foil area.
4. The pole piece of claim 1, wherein a single-sided surface or a double-sided surface of the empty foil area is provided with the adhesive paper.
5. The pole piece of claim 1, wherein the adhesive paper comprises an adhesive layer and a substrate layer, the substrate layer is sandwiched between the two adhesive layers, and the adhesive layer comprises at least one of water glue, oil glue, hot melt glue, natural rubber, synthetic rubber and conductive swelling glue.
6. The pole piece of claim 1, wherein a distance between the gummed paper disposed on the gummed region and the pasting region is 0 to 0.5 mm.
7. An electrical core, comprising a first pole piece, a second pole piece, and a separator disposed between the first pole piece and the second pole piece, wherein the first pole piece and the second pole piece have opposite polarities;
the first and second pole pieces are the pole pieces of any one of claims 1 to 6.
8. The cell of claim 7, wherein the first pole piece, the separator, and the second pole piece are stacked and wound or alternately stacked along a length direction of the first pole piece and the second pole piece to form the cell;
the paste coating area of the first pole piece and the paste coating area of the second pole piece are arranged in an overlapping mode, the empty foil area of the first pole piece and the empty foil area of the second pole piece are respectively arranged at two ends, opposite to each other, of the battery cell in the width direction, and the adhesive tape is continuously arranged between the adhesive tape area of the first pole piece and the adhesive tape area of the second pole piece.
9. The battery cell of claim 8, wherein two adhesive-free regions are respectively located at two ends of the battery cell in the width direction, and each adhesive-free region forms a welding surface at a side surface of the adhesive region.
10. The battery cell of claim 9, further comprising connecting pieces, wherein the two connecting pieces are respectively welded on the welding surfaces at two ends of the battery cell.
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| CN202122977735.8U CN216389432U (en) | 2021-11-30 | 2021-11-30 | Pole piece and battery cell |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122977735.8U CN216389432U (en) | 2021-11-30 | 2021-11-30 | Pole piece and battery cell |
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| CN216389432U true CN216389432U (en) | 2022-04-26 |
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| CN (1) | CN216389432U (en) |
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