CN217035797U - Intermittent coating type electricity core - Google Patents
Intermittent coating type electricity core Download PDFInfo
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- CN217035797U CN217035797U CN202123080464.2U CN202123080464U CN217035797U CN 217035797 U CN217035797 U CN 217035797U CN 202123080464 U CN202123080464 U CN 202123080464U CN 217035797 U CN217035797 U CN 217035797U
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Abstract
The utility model discloses an intermittent coating type battery cell, which comprises a roll core, a positive pole piece, a negative pole piece and an isolation film, wherein the positive pole piece and the negative pole piece are manufactured by intermittent coating, the positive pole piece and the negative pole piece are wound on the roll core at intervals in circles, the isolation film is arranged between the positive pole piece and the negative pole piece and isolates the positive pole piece and the negative pole piece, and the corner area of each circle is a straight edge to form a square battery cell structure when the positive pole piece and the negative pole piece are wound. The corner area of each circle when the positive pole piece and the negative pole piece are wound and the area of each circle along the width direction of the battery cell when the positive pole piece and the negative pole piece are wound are both hollow foils. The utility model changes the coating mode from continuous coating to intermittent coating, namely, the position of the R corner of the original naked electric core is not coated with anode and cathode slurry and is a hollow foil. Naked electric core of intermittent type coating is combined with square hot pressing technology again, carries out the plastic with the foil at R angle, becomes the straight flange by original semi-circular, has just so improved the inside space utilization of electric core greatly.
Description
Technical Field
The utility model belongs to the technical field of new energy batteries, and particularly relates to an intermittent coating type battery cell.
Background
The lithium ion battery as an environment-friendly battery has the advantages of high energy density, high working voltage, high safety performance, long service life and the like. The battery cell cycle life is mainly prolonged, and the safety of the battery cell is ensured.
At present, the conventional coating method is a combination of continuous coating and winding processes, and has several inevitable disadvantages: r angular stress is uneven, lithium is easy to precipitate in the later period of long-term circulation, and the precipitated lithium basically becomes dead lithium, namely capacity fading. In addition, as the lithium dendrite grows, the diaphragm is easy to be punctured, so that the thermal runaway of the battery core is caused, and the consequence is serious. 2. The shape of the R corners on the two sides after winding is approximate to a semicircle and the pole piece gap is large, so that the space utilization rate on the two sides of the R corner of the battery cell (namely the corner area of each circle of pole piece and the area of each circle of pole piece along the width direction of the battery cell) is very low, and the exertion of energy density is limited. The general solution is to change into a lamination process, but a production line must be greatly modified, a new lamination machine must be purchased at high price, and an old and useless winding machine must be reported, so that the investment cost is too high. The lamination process also has the fatal drawback, and the sword is cut the limit too much, and the burr management and control degree of difficulty increases, and electric core factor of safety reduces by a wide margin.
SUMMERY OF THE UTILITY MODEL
The utility model aims to at least solve one of the technical problems in the prior art, therefore, the utility model aims to provide an intermittent coating type battery cell which is simple in structure and convenient to use, the traditional coating mode is changed, continuous coating is changed into intermittent coating, namely, the position of the R angle of the original naked battery cell is not coated with positive and negative electrode slurry and is a hollow foil material; naked electric core of intermittent type coating is combined with square hot pressing technology again, carries out the plastic with the foil at R angle, becomes the straight flange by original semi-circular, has just so improved the inside space utilization of electric core greatly.
In order to realize the purpose, the technical scheme of the utility model is as follows: the utility model provides an intermittent type coating formula electricity core, is including rolling up core, positive pole piece, negative pole piece and barrier film, and positive pole piece and negative pole piece all adopt intermittent type coating manufacturing to form, and positive pole piece and negative pole piece are separated each other and are coiled on rolling up the core in the circle, and the barrier film setting is between positive pole piece and negative pole piece, keeps apart both, and every turn of turning region is the squareness of formation electricity core structure when positive pole piece and negative pole piece are coiled.
Further, the corner area of each turn when the positive electrode plate and the negative electrode plate are wound and the area of each turn along the width direction of the battery cell when the positive electrode plate and the negative electrode plate are wound are both empty foils.
Further, the negative electrode plate comprises a copper foil and negative electrode slurry, and the negative electrode slurry is coated on the copper foil in an intermittent coating mode to form the negative electrode plate.
Further, the positive pole piece comprises an aluminum foil and positive pole slurry, and the positive pole slurry is coated on the aluminum foil in an intermittent coating mode to form the positive pole piece.
Further, the inner circle of the battery core firstly sets up an isolation film on the winding core, the isolation film covers the winding core, the isolation film is provided with a negative pole piece, the negative pole piece covers the isolation film, the isolation film is arranged on the negative pole piece, the isolation film covers the negative pole piece, the isolation film is provided with a positive pole piece, the positive pole piece covers the isolation film, the isolation film is arranged on the positive pole piece, the isolation film covers the positive pole piece, and the negative pole piece is arranged on the isolation film to circulate in sequence.
Furthermore, the corner area of each circle of pole pieces and the inner and outer sides of the area along the width direction of the battery cell are not coated with polar slurry, the inner and outer sides are both hollow foils, and the area along the length direction of the battery cell of each circle of pole pieces except the innermost circle of pole pieces and the outermost circle of pole pieces is coated with polar slurry on both sides.
Further, the innermost circle of the battery core is a negative pole piece, the inner side of the innermost circle of the negative pole piece is not coated with negative slurry and is an empty copper foil, and the outer side of the innermost circle of the negative pole piece is coated with polar slurry; when the number of the layers of the battery cell is odd, the outermost circle of the battery cell is a positive pole piece, the inner side of the outermost circle of the positive pole piece is coated with positive pole slurry, and the outer side of the outermost circle of the positive pole piece is not coated with the positive pole slurry and is an empty aluminum foil; when the number of the electric core layers is an even number, the outermost ring of the electric core is a negative pole piece, the inner side of the outermost ring of the negative pole piece is coated with negative pole slurry, and the outer side of the outermost ring of the negative pole piece is not coated with the negative pole slurry and is an empty copper foil.
Furthermore, the coating length of each circle of the negative pole piece is the same, and the value is W1 (total length of the cell-2) outer coating material wall thickness-cell layer number (copper foil thickness + aluminum foil thickness) - (2 (cell layer number +2) +2) isolation film thickness; the coating length of each circle of the positive pole piece is the same, and the value is W2 which is the length of the coating area of the negative pole piece-3-5 mm which is W1-3-5 mm.
Furthermore, the area of each circle of pole pieces which is not coated with the polar slurry is a left white gap, except the left white gaps of the innermost circle and the outermost circle along the length direction of the battery cell, the length of the left white gap of each circle of the pole pieces is in an arithmetic progression, and the tolerance d is 1 plus the thickness of the positive pole piece +1 plus the thickness of the negative pole piece +2 plus the thickness of the isolating film.
The technical scheme adopted by the utility model has the advantages that:
1. the utility model changes the coating mode from continuous coating to intermittent coating, namely, the position of the R corner of the original naked electric core is not coated with anode and cathode slurry and is a hollow foil. Naked electric core and square hot pressing technology combination of intermittent type coating again, carry out the plastic with the foil at R angle, become the straight flange by original semicircle, just so improved the inside space utilization of electric core greatly; the risk of lithium precipitation at the R angle is reduced, and the cycle life and the safety of the battery cell are improved.
2. The utility model adopts intermittent coating and relatively continuous coating, when the same capacity is designed, the obvious thickness is thinner, and the thickness reduction is particularly obvious for a soft package battery core; the R angle is not coated with the slurry, so that the using amount of the slurry can be reduced, the using amount cost of raw materials is reduced, the energy density is improved, no additional new equipment is needed, and the operability is high.
Drawings
The utility model is described in further detail below with reference to the following figures and detailed description:
fig. 1 is a schematic diagram of an odd number of layers of intermittently coated and wound bare cell;
fig. 2 is an expanded view of the intermittent coating of the negative electrode plates of the bare cells of odd-numbered cells;
fig. 3 is an expanded view of the intermittent coating of the bare cell positive electrode plate of the odd-numbered cell of the utility model;
FIG. 4 is a schematic diagram of an even number of layers of intermittently coated wound bare cells according to the present invention;
fig. 5 is an expanded view of the intermittent coating of the bare cell negative electrode plate of the even-numbered cell of the utility model;
fig. 6 is an expanded view of the intermittent coating of the bare cell positive electrode plate of the even-numbered cell of the utility model;
FIG. 7 is a graph of energy density data for comparative example 1 and example 1;
FIG. 8 is a graph of cycle data for comparative example 1 and example 1.
The labels in the above figures are respectively: 1. a winding core; 2. a positive electrode plate; 3. a negative pole piece; 4. an isolation film; 5. a corner region; 6. each circle is along the width direction area of the cell.
Detailed Description
In the present invention, it is to be understood that the term "length"; "Width"; "Up"; "Down"; "front"; "Back"; "left"; "Right"; "vertical"; "horizontal"; "Top"; "bottom" "inner"; "outer"; "clockwise"; "counterclockwise"; "axial"; "planar direction"; "circumferential" and the like indicate orientations or positional relationships that are based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the indicated device or element must have a particular orientation; constructed and operative in a particular orientation and therefore should not be construed as limiting the utility model.
The R angle of the battery cell is the corner area of each circle of pole piece and the area of each circle of pole piece along the width direction of the battery cell. The definition of the number of the cell layers is as follows: the number of layers of the battery cell is described by the number of layers of the positive winding, that is, the number of layers of the positive winding is equal to the number of layers of the battery cell, the positive electrode coated with the positive paste on both the front and back surfaces of the aluminum foil is one layer, and the positive electrode coated with the positive paste on only one surface of the aluminum foil is a half layer, as shown in fig. 1, the number of positive winding turns is (0.5+1+1) × 2 ═ 5, so that the number of battery cell layers is 5 in fig. 1, and similarly, as shown in fig. 4, the number of positive winding turns is (1+1) × 2 ═ 4, so that the number of battery cell layers is 4 in fig. 2. The length direction of the battery cell is the X direction in the drawing, and the width direction of the battery cell is the Y direction in the drawing.
As shown in fig. 1 to 8, an intermittent coating type battery cell comprises a roll core 1, an anode pole piece 2, a cathode pole piece 3 and a separation film 4, wherein the anode pole piece 2 and the cathode pole piece 3 are manufactured by intermittent coating, the anode pole piece 2 and the cathode pole piece 3 are wound on the roll core 1 at intervals and are wound in circles, the separation film 4 is arranged between the anode pole piece 2 and the cathode pole piece 3 and is separated from the anode pole piece 2 and the cathode pole piece 3, and the corner area 5 of each circle is a straight edge to form a square battery cell structure when the anode pole piece 2 and the cathode pole piece 3 are wound. A negative pole piece 3 is arranged between the two positive pole pieces 2 at intervals, and the negative pole piece 3 and the positive pole piece 2 are separated by an isolating film 4. The corner area 5 of each circle when the positive pole piece 2 and the negative pole piece 3 are wound and the area 6 of each circle along the width direction of the battery cell when the positive pole piece 2 and the negative pole piece 3 are wound are both empty foils. The utility model changes the coating mode from continuous coating to intermittent coating, namely, the position of the R corner of the original naked electric core is not coated with anode and cathode slurry and is a hollow foil. Naked electric core of intermittent type coating is again with square hot pressing technology combination, carries out the plastic with the foil at R angle, becomes the straight flange by original semicircle, has just so improved the inside space utilization of electric core greatly.
The negative electrode plate 3 comprises a copper foil 31 and a negative electrode slurry 32, and the negative electrode slurry 32 is coated on the copper foil 31 by an intermittent coating mode to form the negative electrode plate 3. The positive pole piece 2 comprises an aluminum foil 21 and positive pole slurry 22, and the positive pole slurry 22 is coated on the aluminum foil 21 by an intermittent coating mode to form the positive pole piece 2.
Electric core inner circle sets up barrier film 4 at first on rolling up core 1, barrier film 4 covers rolls up core 1, set up negative pole piece 3 on barrier film 4, negative pole piece 3 covers barrier film 4, set up barrier film 4 at negative pole piece 3, barrier film 4 covers negative pole piece 3, set up positive pole piece 2 on barrier film 4, positive pole piece 2 covers barrier film 4, set up barrier film 4 at positive pole piece 2, barrier film 4 covers positive pole piece 2, it circulates in proper order to set up negative pole piece 3 on barrier film 4. The specific winding mode is as follows: the inner circle of the battery core firstly winds a circle of isolating membrane 4 on a winding core 1, winds a circle of negative pole piece 3 on the isolating membrane 4, winds a circle of isolating membrane 4 on the negative pole piece 3, winds a circle of positive pole piece 2 on the isolating membrane 4, winds the negative pole piece 3 again on the positive pole piece 2 by a circle of isolating membrane 4, and circulates in sequence until the required number of layers is reached, and finally, an outer wrapping material 7 is arranged on the outermost part of the pole pieces, and the outer wrapping material 7 wraps the whole battery core to play a role in protection.
The inner side of the innermost ring of the battery cell is not coated with polar slurry and is in a hollow foil form, and the outer side of the innermost ring of the battery cell is coated with polar slurry; the inner side of the outermost ring of the pole piece of the battery cell is coated with polar slurry, and the outer side of the outermost ring of the pole piece is not coated with polar slurry and is in a hollow foil form. The corner area 5 of each circle of pole pieces and the inner and outer sides of the corner area along the width direction area of the battery cell (namely the R angle of the battery cell) are not coated with polar slurry, the inner and outer sides are both hollow foils, the area of each circle of pole pieces along the length direction of the battery cell except the innermost circle of pole pieces and the outermost circle of pole pieces is coated with double-sided polar slurry, namely, aluminum foils and copper foils at the positions of the positive pole pieces and the negative pole pieces between the innermost circle of pole pieces and the outermost circle of pole pieces except the R angle of the battery cell are both coated with double-sided polar slurry.
The innermost circle of the battery core is a negative pole piece 3, the inner side of the innermost circle of the negative pole piece 3 is not coated with negative slurry 32 and is an empty copper foil, and the outer side of the innermost circle of the negative pole piece 3 is coated with polar slurry; when the number of the battery cell layers is an odd number, the outermost circle of the battery cell is the positive pole piece 2, the inner side of the outermost circle of the positive pole piece 2 is coated with the positive pole slurry 22, and the outer side of the outermost circle of the positive pole piece 2 is not coated with the positive pole slurry 22 and is an empty aluminum foil; when the number of the cell layers is an even number, the outermost ring of the cell is the negative electrode plate 3, the inner side of the outermost ring of the negative electrode plate 3 is coated with the negative electrode slurry 32, and the outer side of the outermost ring of the negative electrode plate 3 is not coated with the negative electrode slurry 32 and is an empty copper foil.
Two roll up core 1 in every electric core, two roll up and be equipped with 2 layers of barrier film between the core 1, 2 layers of barrier film are pressed from both sides at first between two roll up core 1 and then come out from one side and carry out follow-up every circle of coiling, so the number of piles of electric core both ends barrier film is 2 (the number of piles of electric core +2) + 2.
The coating length of each circle of the negative pole piece 3 is the same, and the value is W1 ═ total cell length-2 ═ outer coating material wall thickness-cell layer number (copper foil thickness + aluminum foil thickness) - (2 × (cell layer number +2) +2) × isolation film thickness; the coating length of each circle of the positive pole piece (2) is the same, and the value is W2-3-5 mm-W1-3-5 mm-length of the negative pole piece coating area.
The area of each circle of pole pieces which is not coated with polar slurry is a left white gap, except the left white gaps of the innermost circle and the outermost circle along the length direction of the battery cell, the length of each circle of left white gaps of the pole pieces is in an arithmetic progression, namely, the tolerance d is 1 × the thickness of the positive pole piece +1 × the thickness of the negative pole piece +2 + the thickness of the isolation film.
A. The principle of intermittent coating of odd-number layers of cells is as follows, and 5 layers are taken as shown in fig. 1:
the coating length of each circle of the negative pole piece is the same, and the value W1 is the total length of the cell-2 × the wall thickness of the outer coating material-the number of cell layers (the thickness of copper foil + the thickness of aluminum foil) - (2 × the number of cell layers +2) +2 × the thickness of the isolation film is the total length of the cell-the wall thickness of the outer coating material × 2-5 (the thickness of copper foil + the thickness of aluminum foil + the thickness of 2 isolation film) -6 × the thickness of the isolation film. The number of layers of the electric core is calibrated by using the positive electrode, for example, in fig. 5, one end of the electric core is provided with 3 positive aluminum foils, the other end is provided with 2 positive aluminum foils, the total number of the 5 positive aluminum foils in one electric core is the number of layers of the electric core, and the negative copper foils are the same; the inner side of the innermost circle of the negative electrode is left white, namely the inner side of the copper foil is not coated with negative electrode slurry, and the length of the left white gap is equal to the perimeter of the winding core. The positive and negative sides of the R angle of each circle in the middle are left white, the length of the white gap of each circle is in an equal difference array, namely the difference between the nth gap and the (n-1) th gap is a fixed value, and the specific value d is 1+ the thickness of the positive pole piece +1+ the thickness of the negative pole piece +2 + the thickness of the isolating film. The outer side of the negative electrode has m gaps, and m is the number of winding layers, namely the number of battery cell layers; the negative pole inner side has m-1 gaps, wherein the length of the negative pole inner side from the 2 nd gap is equal to the outer 3 rd gap, namely the inner nth gap is equal to the outer n +1 th gap. An exploded view of the intermittent coating of the bare cell negative electrode plate of one cell is shown in fig. 2 below.
The coating length of each circle of the positive pole piece is the same, and the value W2 is equal to the length of the coating area of the negative pole piece, namely-3-5 mm. The outer side of the outermost ring of the positive electrode is left white, the length of a white gap is equal to the perimeter of the winding needle +2 times the thickness of the battery cell, and the thickness of the battery cell is equal to the number of battery cell layers (the thickness of the positive electrode plate + the thickness of the negative electrode plate +2 times the thickness of the isolating film) +4 times the thickness of the isolating film. The positive and negative surfaces of the R angle of each circle in the middle are left white, the length of the white clearance of each circle is in an equal difference number sequence, namely the difference between the nth clearance and the (n-1) th clearance is a fixed value, and the specific value d is 1+ the thickness of the positive pole piece +1+ the thickness of the negative pole piece +2 + the thickness of the isolation film. m is the number of winding layers, the outer side of the anode has m-1 gaps, the inner side of the anode has m gaps, the 1 st to m-2 nd gaps are formed, and the lengths of the inner and outer side white gaps are kept consistent. The intermittent coating development of the bare cell positive pole piece of one cell is shown in fig. 3.
B. The principle of intermittent coating of even-numbered layers of cells is as follows, and 4 layers are taken as shown in fig. 4:
the coating length of each circle of the negative pole piece is the same, and the value W1 is the total length of the cell-2 × the thickness of the outer coating material-the number of cell layers (the thickness of copper foil + the thickness of aluminum foil) - (2 × the number of cell layers +2) +2 × the thickness of the isolating film is the total length of the cell-the thickness of the outer coating material-2-4 × the thickness of the copper foil + the thickness of aluminum foil +2 × the thickness of the isolating film) -6 × the thickness of the isolating film. The inner side of the innermost circle of the negative electrode is left white, and the length of a white clearance is equal to the perimeter of the winding needle. The outer side of the outermost ring of the negative electrode is also left white, the length of the left white gap is equal to the perimeter of the winding needle +2 cell thickness, and the cell thickness is equal to the number of cell layers (the thickness of the positive electrode plate + the thickness of the negative electrode plate +2 separating film thickness) +4 separating film thickness. The positive and negative sides of the R angle of each circle in the middle are left white, the length of the white gap of each circle is in an equal difference array, namely the difference between the nth gap and the (n-1) th gap is a fixed value, and the specific value d is 1+ the thickness of the positive pole piece +1+ the thickness of the negative pole piece +2 + the thickness of the isolating film. The outer side of the negative electrode has m gaps, and m is the number of winding layers; the negative pole inside also has m gaps, wherein the length of the negative pole inside from the 2 nd gap is equal to the outer 3 rd gap, i.e. the inner nth gap is equal to the outer n +1 th gap. An expanded view of the intermittent coating of the bare cell negative electrode sheet of one cell is shown in fig. 5.
The coating length of each circle of the positive pole piece is the same, and the value W2 is equal to the length of the coating area of the negative pole piece, namely-3-5 mm. The positive and negative surfaces of each circle of the R angle are left white, the length of the white gaps of each circle is in an equal difference array, namely the difference between the nth gap and the (n-1) th gap is a fixed value, and the specific value d is 1+ 2 + the thickness of the positive pole piece and the negative pole piece and the thickness of the isolating film. m is the number of winding layers, m-1 gaps are arranged on the inner side and the outer side of the anode, and the lengths of the left gaps on the inner side and the outer side of the same turn number are kept consistent. An expanded view of the intermittent coating of the bare cell positive electrode sheet of one cell is shown in fig. 6.
Comparative example 1[ continuous winding ]
The lithium iron phosphate anode main material with the mass ratio of 95% and the graphite cathode main material with the mass ratio of 95% are used for manufacturing a 30Ah hard-shell battery by using a conventional continuous coating process, the external dimension of a battery core is 26mm x 148mm x 95mm, the capacity value is tested after the battery core is manufactured, the capacity value is weighed, the energy density is calculated, and then a 1ea sample is randomly selected for a cycle test.
Wherein the 30Ah hard shell manufacturing process comprises the following steps:
1. adding 95% of lithium iron phosphate anode main material, 2% of conductive carbon black, 3% of polyvinylidene fluoride and the like in mass ratio into a stirring tank, adding an N-methyl pyrrolidone solvent, and then stirring at high speed to prepare anode slurry; 2. and (2) continuously coating the positive electrode slurry in the step (1) on an aluminum foil, and then baking, rolling and cutting pieces at 100 +/-5 ℃ to prepare the positive electrode piece. 3. Adding 95% of graphite, 2% of conductive carbon black, 1.5% of styrene butadiene rubber, 1.5% of sodium carboxymethylcellulose and the like in mass ratio into a stirring tank, adding deionized water, and then stirring at high speed to prepare negative electrode slurry; 4. and (4) continuously coating the negative electrode slurry in the step (3) on copper foil, and then baking at 95 +/-5 ℃, rolling and cutting into pieces to obtain the negative electrode piece. 5. Winding, assembling, baking at 90 +/-5 ℃, injecting electrolyte, packaging, forming and the like to obtain the soft package battery cell. 6. Testing the capacity value and weighing after the formation of the hard shell battery cell, and calculating to obtain energy density data, wherein the average value of the energy density is 156.5 Wh/kg; and then randomly selecting a 1ea sample to perform high-temperature cycle test.
Example 1[ batch coating ]
The lithium iron phosphate positive electrode main material with the mass ratio of 95% and the graphite negative electrode main material with the mass ratio of 95% are used for manufacturing a 30Ah hard shell battery by adopting an intermittent coating process, the external dimension of a battery core is 26mm x 148mm x 95mm, the capacity value is tested after the battery core is manufactured, the battery core is weighed, the energy density is calculated, and then a 1ea sample is randomly selected for a cycle test.
Wherein the 30Ah hard shell manufacturing process comprises the following steps:
1. adding 95% of lithium iron phosphate anode main material, 2% of conductive carbon black, 3% of polyvinylidene fluoride and the like in mass ratio into a stirring tank, adding an N-methyl pyrrolidone solvent, and then stirring at high speed to prepare anode slurry; 2. and (3) intermittently coating the positive electrode slurry in the step (1) on an aluminum foil, and then baking, rolling and cutting pieces at 100 +/-5 ℃ to prepare the positive electrode piece. The number of winding layers of the cell was 38. The inner side and the outer side of the anode are respectively provided with 38 coating areas, the lengths of the coating areas are the length of the anode coating area-the design tolerance of the anode, wherein the length of the anode coating area is 145mm, and the design tolerance of the anode and the cathode is 4mm, so that the length of the anode coating area is 141 mm. The theoretical lengths of the gaps 1 st and 2 … 37 th in the positive electrode inner uncoated area are shown in the following table, and the number of layers is even, so the uncoated areas on the inner and outer sides of the positive electrode are the same. 3. Baking at 100 +/-5 ℃, rolling and cutting into pieces after coating to prepare a positive pole piece; the positive pole piece blank gap is shown in the following table:
inside and outside of the positive electrode
| The m- |
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| Theory of the utility model | 0.31 | 0.60 | 0.89 | 1.17 | 1.46 | 1.75 | 2.03 | 2.32 | 2.61 | 2.89 |
| In fact | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 2.0 | 2.3 | 2.6 | 2.9 |
| M gap | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| Theory of the utility model | 3.18 | 3.47 | 3.76 | 4.04 | 4.33 | 4.62 | 4.90 | 5.19 | 5.48 | 5.77 |
| In fact | 3.2 | 3.5 | 3.8 | 4.0 | 4.3 | 4.6 | 4.9 | 5.2 | 5.5 | 5.8 |
| The m- |
21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
| Theory of the utility model | 6.05 | 6.34 | 6.63 | 6.91 | 7.20 | 7.49 | 7.78 | 8.06 | 8.35 | 8.64 |
| In fact | 6.1 | 6.3 | 6.6 | 6.9 | 7.2 | 7.5 | 7.8 | 8.1 | 8.3 | 8.6 |
| |
31 | 32 | 33 | 34 | 35 | 36 | 37 | |||
| Theory of the utility model | 8.92 | 9.21 | 9.50 | 9.79 | 10.07 | 10.36 | 10.65 | |||
| In fact | 8.9 | 9.2 | 9.5 | 9.8 | 10.1 | 10.4 | 10.6 |
4. Adding 95% of graphite, 2% of conductive carbon black, 1.5% of styrene butadiene rubber, 1.5% of sodium carboxymethylcellulose and the like in mass ratio into a stirring tank, adding deionized water, and then stirring at high speed to prepare negative electrode slurry; 5. and (3) intermittently coating the negative electrode slurry on the copper foil, wherein the number of negative electrode coating areas is 38, and the lengths of the negative electrode coating areas are 145 mm. The length of the No. 1 non-coating area on the inner side of the negative electrode is 290mm, the length of the No. 2 and No. 3 … n non-coating areas is shown in the following table, and the production line can not produce the length within <2mm, so that only 30 gaps are actually formed; the inside white space of the negative pole piece is shown in the following table:
inner side of the negative electrode
| |
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| Theory of the utility model | 290.00 | 0.60 | 0.89 | 1.17 | 1.46 | 1.75 | 2.03 | 2.32 | 2.61 | 2.89 |
| In fact | 290.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 2.0 | 2.3 | 2.6 | 2.9 |
| M gap | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| Theory of the utility model | 3.18 | 3.47 | 3.76 | 4.04 | 4.33 | 4.62 | 4.90 | 5.19 | 5.48 | 5.77 |
| In fact | 3.2 | 3.5 | 3.8 | 4.0 | 4.3 | 4.6 | 4.9 | 5.2 | 5.5 | 5.8 |
| The m- |
21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
| Theory of the utility model | 6.05 | 6.34 | 6.63 | 6.91 | 7.20 | 7.49 | 7.78 | 8.06 | 8.35 | 8.64 |
| In fact | 6.1 | 6.3 | 6.6 | 6.9 | 7.2 | 7.5 | 7.8 | 8.1 | 8.3 | 8.6 |
| The m- |
31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | ||
| Theory of the utility model | 8.92 | 9.21 | 9.50 | 9.79 | 10.07 | 10.36 | 10.65 | 10.93 | ||
| In fact | 8.9 | 9.2 | 9.5 | 9.8 | 10.1 | 10.4 | 10.6 | 10.9 |
The length of the 1 st, 2 nd, 3 … th uncoated area in the uncoated area outside the negative electrode is as follows, and because the length production line can not be made within the range of less than 2mm, only 30 gaps are actually formed; the outside white space of the negative pole piece is shown in the following table:
outside of the negative electrode
| |
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 0 | 10 |
| Theory of the utility model | 0.02 | 0.31 | 0.60 | 0.89 | 1.17 | 1.46 | 1.75 | 2.03 | 2.32 | 2.61 |
| In |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 23 | 26 |
| M gap | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| Theory of the utility model | 2.89 | 3.18 | 3.47 | 3.76 | 4.04 | 4.33 | 4.62 | 4.90 | 5.19 | 5.48 |
| In fact | 2.9 | 3.2 | 3.5 | 3.8 | 4.0 | 4.3 | 4.6 | 4.9 | 5.2 | 5.5 |
| |
21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
| Theory of the utility model | 5.77 | 6.05 | 6.34 | 6.63 | 6.91 | 7.20 | 7.49 | 7.78 | 8.06 | 8.35 |
| In fact | 5.8 | 6.1 | 6.3 | 6.6 | 6.9 | 7.2 | 7.5 | 7.8 | 8.1 | 8.3 |
| |
31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | ||
| Theory of the utility model | 8.64 | 8.92 | 9.21 | 9.50 | 9.79 | 10.07 | 10.36 | 300.96 | ||
| In fact | 8.6 | 8.9 | 9.2 | 9.5 | 9.8 | 10.1 | 10.4 | 301.0 |
6. And baking at 95 +/-5 ℃, rolling and cutting into pieces after coating to prepare the negative pole piece. 7. Winding, assembling, baking at 90 +/-5 ℃, injecting electrolyte, packaging, forming and the like to obtain the soft package battery core. 8. Testing the capacity value and weighing after the formation of the hard shell battery core, and calculating to obtain energy density data, wherein the mean value of the energy density is 158.5Wh/kg, as shown in figure 7; and then randomly selecting 1ea sample to carry out high-temperature cycle test, the cycle result of the example 1 is obviously better than that of the comparative example 1, as shown in figure 8.
The utility model changes the coating mode from continuous coating to intermittent coating, namely, the position of the R corner of the original naked electric core is not coated with anode and cathode slurry and is a hollow foil. Naked electric core and square hot pressing technology combination of intermittent type coating again, carry out the plastic with the foil at R angle, become the straight flange by original semicircle, just so improved the inside space utilization of electric core greatly; the risk of lithium precipitation at the R angle is reduced, and the cycle life and the safety of the battery cell are improved.
When the same capacity is designed by adopting intermittent coating and relatively continuous coating, the thickness is obviously thinner, and the thickness reduction is especially obvious for a soft package battery cell; the R angle is not coated with the slurry, so that the use amount of the slurry can be reduced, the use amount cost of raw materials can be reduced, the energy density can be improved, no additional new equipment is needed, and the operability is high.
The present invention is described above with reference to the accompanying drawings, and it is obvious that the present invention is not limited to the above embodiments, and it is within the scope of the present invention to adopt various insubstantial modifications of the technical solution of the present invention, or to directly apply the concept and technical solution of the present invention to other fields without any modification.
Claims (10)
1. An intermittent coating formula electricity core which characterized in that: including rolling up core (1), positive pole piece (2), negative pole piece (3) and barrier film (4), positive pole piece (2) and negative pole piece (3) all adopt intermittent type coating manufacturing to form, positive pole piece (2) and negative pole piece (3) are separated each other and are coiled on rolling up core (1) in circles, barrier film (4) set up between positive pole piece (2) and negative pole piece (3), keep apart both, every turn of corner region (5) are the squareness electricity core structure when positive pole piece (2) and negative pole piece (3) are coiled.
2. An intermittently coated cell according to claim 1, wherein: and the corner area (5) of each circle when the positive pole piece (2) and the negative pole piece (3) are wound and the area (6) of each circle along the width direction of the battery cell when the positive pole piece (2) and the negative pole piece (3) are wound are both hollow foils.
3. An intermittently coated cell according to claim 2, wherein: the negative pole piece (3) comprises a copper foil (31) and negative pole slurry (32), and the negative pole slurry (32) is coated on the copper foil (31) in an intermittent coating mode to form the negative pole piece (3).
4. An intermittently coated cell according to claim 3, wherein: the positive pole piece (2) comprises an aluminum foil (21) and positive pole slurry (22), and the positive pole slurry (22) is coated on the aluminum foil (21) in an intermittent coating mode to form the positive pole piece (2).
5. An intermittently coated cell according to claim 4, wherein: the battery core firstly sets up barrier film (4) on rolling up core (1) at first, barrier film (4) cover rolls up core (1), set up negative pole piece (3) on barrier film (4), negative pole piece (3) cover barrier film (4), set up barrier film (4) in negative pole piece (3), barrier film (4) cover negative pole piece (3), set up positive pole piece (2) on barrier film (4), positive pole piece (2) cover barrier film (4), set up barrier film (4) in positive pole piece (2), barrier film (4) cover positive pole piece (2), it circulates in proper order to set up negative pole piece (3) on barrier film (4).
6. An intermittently coated cell according to claim 5, wherein: the inner side of the innermost ring of the battery cell is not coated with polar slurry and is in a hollow foil form, and the outer side of the innermost ring of the battery cell is coated with polar slurry; the inner side of the outermost ring of the pole piece of the battery cell is coated with polar slurry, and the outer side of the outermost ring of the pole piece is not coated with polar slurry and is in a hollow foil form.
7. An intermittently coated cell according to claim 6, wherein: the corner area (5) of each circle of pole pieces and the inner side and the outer side of the area along the width direction of the battery cell are not coated with polar slurry, the inner side and the outer side are both hollow foils, and the area of each circle of pole pieces along the length direction of the battery cell except the innermost circle of pole pieces and the outermost circle of pole pieces is coated with polar slurry on two sides.
8. An intermittently coated cell according to claim 7, wherein: the innermost circle of the battery core is a negative pole piece (3), the inner side of the innermost circle of the negative pole piece (3) is not coated with negative slurry (32) and is an empty copper foil, and the outer side of the innermost circle of the negative pole piece (3) is coated with polar slurry; when the number of the layers of the battery cell is odd, the outermost circle of the battery cell is the positive pole piece (2), the inner side of the outermost circle of the positive pole piece (2) is coated with positive pole slurry (22), and the outer side of the outermost circle of the positive pole piece (2) is not coated with the positive pole slurry (22) and is an empty aluminum foil; when the number of the cell layers is an even number, the outermost ring of the cell is the negative pole piece (3), the inner side of the outermost ring of the negative pole piece (3) is coated with the negative pole slurry (32), and the outer side of the outermost ring of the negative pole piece (3) is not coated with the negative pole slurry (32) and is an empty copper foil.
9. An intermittently coated cell according to claim 8, wherein: the coating length of each circle of the negative pole piece (3) is the same, and the value is W1 (total length of the cell-2) outer coating material wall thickness-cell layer number (copper foil thickness + aluminum foil thickness) - (2 (cell layer number +2) +2) isolation film thickness; the coating length of each circle of the positive pole piece (2) is the same, and the value is W2-3-5 mm-W1-3-5 mm-length of the negative pole piece coating area.
10. An intermittently coated cell according to claim 9, wherein: the area of each circle of pole pieces which is not coated with the polar slurry is a left white gap, except the left white gaps of the innermost circle and the outermost circle along the length direction of the battery cell, the length of each circle of left white gaps of the pole pieces is in an arithmetic progression, and the tolerance d is 1 × the thickness of the positive pole piece +1 × the thickness of the negative pole piece +2 × the thickness of the isolation film.
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| CN202123080464.2U CN217035797U (en) | 2021-12-09 | 2021-12-09 | Intermittent coating type electricity core |
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