CN221262655U - Pole piece, battery core and battery - Google Patents

Abstract

The utility model provides a pole piece, which comprises a pole piece body and a plurality of monopole lugs which are connected to the edge of one side of the pole piece body in the length direction and are distributed at intervals; the lengths of the monopole ears are the same, and the widths are gradually changed according to the arrangement sequence; the width gradual change mode of the monopole ear is as follows: the widths of the monopole ears are sequentially increased and then reduced according to the arrangement sequence, so that the head monopole ear and the tail monopole ear have the same width; or the widths of the monopole ears are sequentially reduced and then increased according to the arrangement sequence, so that the head monopole ear and the tail monopole ear have the same width. The battery cell formed by winding the positive/negative electrode plate with the structural design is provided with the positive/negative electrode lugs with hexagonal or hourglass-shaped end faces, so that the compatibility of the electrode lugs is enhanced, dislocation rejection caused by fluctuation of a winding process and the problem of thickness consistency of materials is reduced, and the winding rate is greatly improved.

Description

Pole piece, battery core and battery

Technical Field

The utility model belongs to the field of batteries, and particularly relates to a pole piece, an electric core and a battery.

Background

Lithium batteries are a common battery type, have the advantages of high energy density, light weight, good cycle life and the like, and are widely applied to the fields of mobile electronic equipment, electric vehicles and the like. Currently, multipolar ear batteries with higher power output and energy density are widely used in the fields of electric automobiles, energy storage systems, unmanned aerial vehicles, mobile power supplies and the like. Through the increase of the number of the lugs and the reasonable layout of the positions of the lugs, the multi-lug battery has larger electrode surface area and better current transmission channel, and the power density of the battery is greatly improved, so that the battery can be discharged and charged more quickly.

In the preparation process of the battery core of the multipolar ear battery, a current collector edge empty foil area is reserved at the long edge of a full material area for die cutting, so that monopolar ears with specific shapes and specifications and monopolar ear spacing are formed; and then winding the cut and die-cut positive electrode plate, the cut and die-cut negative electrode plate and the diaphragm in a certain order to form a core structure of the battery, namely a battery core. As a key link of an assembly section of a middle process in battery manufacturing, a winding process of a square battery has high requirement and high difficulty on tension control, and in actual production, the phenomenon that the alignment degree of tabs is difficult to meet the regulation often occurs after winding. At present, the pole piece is generally obtained by die cutting and is a monopole lug with consistent size. The single-pole lugs with the same size have poor compatibility for dislocation of the pole lugs after winding, and if the dislocation exceeds the requirement, the rejection is increased. Meanwhile, after the single-pole lugs are misplaced, the irregular pole lugs formed by winding are easy to collide with clamps in the streamline transportation of the object, so that the battery cell is scrapped.

Disclosure of utility model

In order to solve the problem of dislocation of the monopole lugs in the prior art, the width of the monopole lugs of the pole piece is gradually changed, so that the battery core manufactured by winding the pole piece is provided with the positive/negative lugs with hexagonal or hourglass end faces, the problem of dislocation of the pole lugs caused by fluctuation of a winding process and the problem of consistency of thickness of materials in the prior art is solved, the rate of the winding process is improved, the probability of collision of the positive/negative lugs with a clamp in the battery core transportation process in the battery assembly stage is reduced, and the rejection rate of the battery core is greatly reduced.

The technical scheme adopted by the utility model is as follows: a pole piece comprises a pole piece body and a plurality of monopole lugs which are connected to the edge of one side of the pole piece body in the length direction and are distributed at intervals; the lengths of the monopole ears are the same, and the widths are gradually changed according to the arrangement sequence; the width gradual change mode of the monopole ear is as follows:

The widths of the monopole ears are sequentially increased and then reduced according to the arrangement sequence, so that the head monopole ear and the tail monopole ear have the same width;

Or (b)

The width of each monopole ear is sequentially reduced and then increased according to the arrangement sequence, so that the head monopole ear and the tail monopole ear have the same width.

In actual production, the problem of fluctuation of the winding process and consistency of the thickness of materials often causes dislocation of the electrode lugs of the battery core, and the inventor groups the common dislocation of the electrode lugs into four types as shown in fig. 1, namely (1) a plurality of positive/negative monopole lugs are simultaneously deviated to the winding direction or the reverse winding direction; (2) The positive/negative monopole ears are offset in one winding direction and the other negative monopole ears are offset in the opposite winding direction, so that a splayed dislocation is formed; (3) The positive/negative monopole ears are offset in one winding direction and the other negative monopole ears are offset in the opposite winding direction, so that a splayed dislocation is formed; (4) The positive/negative monopole ears are simultaneously shifted to the winding direction and then the reverse winding direction or the reverse winding direction and then the winding direction, so that U-shaped dislocation is formed. For the four common dislocation types, the utility model provides two monopole lug width gradual change designs, namely the monopole lug width is firstly increased and then decreased or is firstly decreased and then increased, so that an electric core formed by winding a positive/negative plate adopting the structural design is provided with positive/negative lugs with hexagonal or hourglass-shaped end faces. With reference to fig. 2, the hexagonal lug design on the end surface is generally used for overcoming the dislocation types shown in the above-mentioned (1) - (3), and the hourglass-shaped lug design on the end surface is generally used for overcoming the U-shaped dislocation shown in the above-mentioned (4), so that the compatibility of the lug dislocation is enhanced by the two design schemes, dislocation rejection caused by fluctuation of the winding process and the problem of thickness consistency of materials is reduced, and the winding rate is greatly improved. Meanwhile, the lug formed by winding by adopting the design scheme has a more regular structure, and the problem that the lug collides with a clamp in logistics line transportation to further cause scrapping of the battery cell is avoided.

Preferably, the monopole ears are of trapezoid structures, and the width of the monopole ears at the part adjacent to the pole piece body is larger than that at the part far away from the pole piece body. The monopole lug with the trapezoid design can improve the current density difference, so that the current is more uniformly distributed on the monopole lug, and the battery performance is improved; at the same time, the diffusion path of the electrode is reduced to reduce the resistance and increase the reaction rate of the battery. In addition, the trapezoid monopole lug can also increase the effective area, and the capacity and the energy storage capacity of the battery are improved.

Preferably, the spacing widths of the monopole ears are sequentially increased or sequentially decreased in the length direction of the pole piece body. In the wound battery, since the winding circumference of the inner ring is smaller than that of the outer ring, the distance between the monopolar lugs of the inner ring is relatively small for the pole pieces of the wound battery design, and the distance between the monopolar lugs of the outer ring is relatively large to adapt to the large winding diameter of the outer ring.

The utility model also provides a battery cell, which comprises the pole piece; the pole piece is in a winding shape; the pole pieces are arranged in a laminated mode, the widths of the pole pieces are sequentially changed layer by layer, and the pole pieces with hexagonal or hourglass-shaped end faces are formed.

The positive plate, the negative plate and the diaphragm which are prepared based on the pole piece are stacked layer by layer and then are subjected to a winding procedure; wherein, positive pole piece or negative pole piece adopts the pole piece that has the same monopole ear width design. Referring to fig. 3 to 5, if the positive electrode sheet and the negative electrode sheet both adopt electrode sheets with single-electrode tab widths of increasing and then decreasing, the wound battery cell is provided with a positive electrode tab and a negative electrode tab with hexagonal end faces; referring to fig. 6 to 8, if the positive electrode sheet and the negative electrode sheet both adopt electrode sheets with monopole lug widths of decreasing first and then increasing second, the battery cell formed after winding has a positive electrode lug and a negative electrode lug with an hourglass-shaped end face.

Preferably, the battery cell is square. According to different winding modes, the winding battery core can be divided into a cylindrical shape or a square shape, and compared with the cylindrical winding battery core, the square winding battery core is more widely used due to the advantages of high packaging reliability, high system energy efficiency, high energy density, simpler structure and the like.

Preferably, the tab includes a positive tab and a negative tab, and the positive tab and the negative tab are located at the same end of the battery cell. According to the arrangement of the different positions of the monopole lugs on the positive plate and the negative plate, the battery core formed after winding has different construction modes, and the positive electrode lug and the negative electrode lug can be positioned at the same end or different ends of the battery core. The positive electrode tab and the negative electrode tab are positioned at the same end of the battery core, so that the advantages of simplifying a current path, improving safety, realizing charge-discharge balance and the like are facilitated, and the performance and reliability of the battery are further improved.

The utility model also provides a battery comprising: a housing having two poles; the battery cell is fixed in the shell, the positive electrode lug in the battery cell is connected with one of the poles, and the negative electrode lug in the battery cell is connected with the other pole.

Preferably, an insulating layer is arranged between the shell and the battery cell. Before the battery cell is inserted into the shell, an insulating layer is arranged at the bottom of the shell to prevent the internal short circuit of the battery.

The utility model has the beneficial effects that: aiming at the common dislocation type of the electrode lugs of the battery core in the winding procedure in the actual production process, the utility model provides two designs of gradual change of the width of the electrode lugs, namely the width of the electrode lugs is firstly increased and then decreased or firstly decreased and then increased, so that the battery core formed by winding the positive/negative electrode plate adopting the structural design has the positive/negative electrode lugs with hexagonal or hourglass-shaped end faces. The two design schemes enhance the compatibility of the pole lugs, reduce misplacement scrapping caused by fluctuation of a winding process and the problem of thickness consistency of materials, and greatly improve the winding rate. Meanwhile, the lug formed by winding by adopting the design scheme has a more regular structure, and the problem that the lug collides with a clamp in logistics line transportation to further cause scrapping of the battery cell is avoided.

Drawings

Fig. 1 is a typical tab misalignment type.

Fig. 2 is a graph showing the comparison of effects produced by the tab design according to the present utility model.

Fig. 3 is a schematic view of a pole piece structure in embodiment 1.

Fig. 4 is a schematic view of a battery structure in embodiment 1.

Fig. 5 is a side view of one of the batteries in example 1.

Fig. 6 is a schematic view of a pole piece structure in embodiment 2.

Fig. 7 is a schematic view of a battery structure in embodiment 2.

Fig. 8 is a side view of one of the batteries in example 2.

Icon: 10-pole piece, 101-pole piece body, 102-monopole ear, 20-pole ear and 30-shell.

Detailed Description

The following specific examples are presented to illustrate the present utility model, and those skilled in the art will readily appreciate the additional advantages and capabilities of the present utility model as disclosed herein. The utility model may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present utility model. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict.

Example 1

The embodiment provides a pole piece 10 for a winding square battery, which is used for overcoming the dislocation types shown in fig. 1 (1) - (3). Referring to fig. 3, the pole piece 10 in this embodiment includes a pole piece body 101 and a plurality of monopole ears 102, where the monopole ears 102 are connected to one side edge of the pole piece body 101 at intervals, and the widths of the monopole ears 102 sequentially increase and decrease in sequence according to the arrangement order, so that the head monopole ear 102 and the tail monopole ear 102 have the same width.

During production, the pole piece 10 is typically obtained by slitting, die cutting a foil coated with a positive/negative electrode paste (i.e., a positive/negative electrode film sheet) so that the pole piece 10 has monopolar ears 102 of a particular shape and size, and a particular monopolar ear spacing. In this embodiment, instead of the single-sized monopole ear 102 of the prior art, the monopole ear 102 is designed to have a width that increases and decreases sequentially in the order of arrangement. For convenience of description, in the present embodiment, a longitudinal direction (shown as B in fig. 3) and a width direction (shown as a in fig. 3) perpendicular to each other are defined for the pole piece body 101. Among all the monopole ears 102 connected to the pole piece body 101, each monopole ear 102 has the same length in the length direction and different widths in the width direction, and the widths of the monopole ears 102 are sequentially increased and then decreased in the arrangement order, so that the width of the monopole ear 102 at the center of the pole piece 10 is greater than the width of the monopole ear 102 at both ends, and the widths of the head and tail monopole ears 102 and 102 should be identical. As shown in fig. 3, according to the direction a, the width of the second monopole ear 102 on the left side is larger than the width of the first monopole ear 102 from the left to the right, the width of the third monopole ear 102 is larger than the width of the second monopole ear 102, the fourth monopole ear 102 has the largest width in the illustrated pole piece 10, after which the width of the monopole ear 102 gradually decreases such that the width of the trailing monopole ear 102 on the rightmost side decreases to the same width as the leftmost first monopole ear 102. In the actual production process, the number of the monopolar tabs 102 is not particularly limited, since the number of the monopolar tabs 102 is related to the thickness and the size of the wound battery cell manufactured using the pole piece 10.

In the winding process, since the winding circumference of the inner ring is smaller than that of the outer ring, in order to align and laminate all the monopolar lugs 102, the lug spacing between the monopolar lugs 102 of the inner ring should be relatively small, and the lug spacing between the monopolar lugs 102 of the outer ring should be relatively large to adapt to the large winding diameter of the outer ring, i.e. the interval widths of a plurality of the monopolar lugs 102 are sequentially changed along the length direction of the pole piece body 101. As shown in fig. 3, the pole piece 10 is shown with respect to the direction a, and the distance between two adjacent monopole ears 102 is gradually increased from left to right. Therefore, when the battery cell is fabricated by winding, the leftmost leading monopolar lug 102 is positioned on the opposite inner ring, and the rightmost trailing monopolar lug 102 is positioned on the opposite outer ring. Similarly, in another embodiment, if the leftmost side is the trailing monopole ear 102 located opposite the outer race and the rightmost side is the leading monopole ear 102 located opposite the inner race, the distance between two adjacent monopole ears 102 is gradually reduced from left to right with reference to the direction indicated by a.

To further improve the battery performance, it is preferable that the monopole tab 102 has a trapezoid structure, and the monopole tab 102 has a greater width at a portion adjacent to the pole piece body 101 than at a portion distant from the pole piece body 101. With reference to fig. 3, the width of a single monopole ear 102 is tapered from bottom to top in the direction indicated by B; but the variation in width is uniform for different monopolar ears 102, and each of the monopolar ears 102 has the same height in the B direction.

The embodiment also provides a square battery cell formed by winding the pole piece 10. The positive electrode plate 10 and the negative electrode plate 10 of the battery core are both electrode plates 10 respectively coated with corresponding positive/negative electrode slurries, the widths of the plurality of monopolar lugs 102 on the electrode plates 10 are 'increased first and then reduced', and meanwhile, the head monopolar lug 102 and the tail monopolar lug 102 have the same width. The positive plate, the diaphragm, the negative plate and the diaphragm are stacked layer by layer and then wound, so that the positive plate and the negative plate are wound, a plurality of monopole lugs 102 on the positive plate and the negative plate are arranged in a laminated mode after being wound, and the widths of the monopole lugs 102 are changed layer by layer in sequence, so that the positive electrode lug 20 and the negative electrode lug 20 with hexagonal end faces are formed. Taking the pole piece 10 shown in fig. 3 as an example, the leftmost head end monopole lug 102 is used as a winding starting point, namely, is positioned on the opposite inner ring; while the rightmost trailing monopole lug 102 serves as the end of winding and is located on the opposite outer race. After winding, the monopolar tabs 102 are stacked, and the resulting cell should theoretically have a tab 20 with a hexagonal end face as shown in fig. 4 and 5. However, in the actual production process, due to the fluctuation of the winding process and the problem of consistency of the thickness of the materials, the dislocation problem of the tab 20 occurs, and if the pole piece 10 designed by the single monopole lug 102 is adopted, the tab 20 with the parallelogram end face shown in fig. 2 occurs after winding, so that the battery cell is scrapped; by adopting the pole piece 10 provided in this embodiment, the projections of the head-end monopole lug 102 and the tail-end monopole lug 102 on the vertical direction fall into the projection of the monopole lug 102 with the largest middle width, so that the fluctuation of the winding process and the error caused by the problem of the thickness consistency of materials are counteracted, the formed pole lug 20 has more regular end surfaces, the contact area of the monopole lugs 102 is larger, and the winding rate is greatly improved.

To further improve the performance and reliability of the battery, as a preferred embodiment, the positive electrode tab 20 and the negative electrode tab 20 are located at the same end of the battery cell. When the positive plate, the diaphragm, the negative plate and the diaphragm are stacked layer by layer, the side edges of the positive plate 10 and the negative plate 10 with the monopole lug 102 are placed on the same side, and the positive electrode lug 20 and the negative electrode lug 20 of the wound battery cell are positioned at the same end of the battery cell.

On the basis of the above battery cells, this embodiment also provides a square battery, as shown in fig. 4 and 5. The battery includes a housing 30 and the electrical cells described above. The housing 30 has two poles (not depicted); the battery cell is fixed in the shell 30, the positive electrode tab 20 in the battery cell is connected with one of the poles, and the negative electrode tab 20 in the battery cell is connected with the other one of the poles. The illustrated battery may also include two or more battery cells, with the positive tab 20 or the negative tab 20 of each of the plurality of battery cells being welded and connected to a corresponding post via a flexible tab. Placing an insulating layer at the bottom of the housing 30 prevents internal shorting of the battery before the cells are inserted into the housing 30. The insulating layer generally comprises an insulating pad or an insulating film, and common insulating materials are generally polypropylene films, adhesive papers, ceramic papers, polymer coatings and the like. In addition, the housing 30 may be made of a hard metal material such as an aluminum case or a steel case to protect the internal battery cells.

Example 2

Example 2 provides a pole piece 10 for a wound prismatic battery to overcome the "U-shaped" misalignment described above as shown in fig. 1 (4). Referring to fig. 6, the difference from embodiment 1 is that the width of each of the monopole ears 102 of the pole piece 10 provided in embodiment 2 is sequentially decreased and then increased according to the arrangement order, so that the head monopole ear 102 and the tail monopole ear 102 have the same width. For convenience of description, in the present embodiment, a longitudinal direction (shown as B in fig. 6) and a width direction (shown as a in fig. 6) perpendicular to each other are defined for the pole piece body 101. Of all the monopole ears 102 connected to the pole piece body 101, each monopole ear 102 has the same length in the length direction and different widths in the width direction, and the widths of the monopole ears 102 are reduced and increased, so that the width of the monopole ear 102 at the center of the pole piece 10 is smaller than that of the monopole ears 102 at the two ends, and the widths of the front and rear monopole ears 102 and 102 are consistent. As shown in fig. 6, according to the direction a, the width of the second monopole ear 102 on the left side is smaller than the width of the first monopole ear 102 from the left to the right, the width of the third monopole ear 102 is smaller than the width of the second monopole ear 102, the fourth monopole ear 102 has the smallest width in the illustrated pole piece 10, after which the width of the monopole ear 102 is gradually increased such that the width of the trailing monopole ear 102 on the rightmost side is increased to the same width as the leftmost first monopole ear 102.

The present embodiment further provides a square battery core formed by winding the above-mentioned pole piece 10, the positive pole piece and the negative pole piece of the battery core are both made of the pole piece 10 coated with the corresponding positive/negative electrode slurry respectively as described above, the widths of the multiple monopole ears 102 on the pole piece 10 are "reduced before increased", meanwhile, the front monopole ear and the rear monopole ear have the same width, and the specific winding manner is the same as that of embodiment 1, so that the positive pole piece and the negative pole piece are in a winding shape, the multiple monopole ears 102 corresponding to the positive pole piece and the negative pole piece are in a lamination arrangement after being wound, and the widths of the monopole ears 102 are sequentially changed layer by layer, so as to form the positive pole ear 20 and the negative pole ear 20 with the end faces in an hourglass shape. Taking the pole piece 10 shown in fig. 6 as an example, the leftmost head end monopole lug 102 is used as a winding starting point, namely, is positioned on the opposite inner ring; while the rightmost trailing monopole lug 102 serves as the end of winding and is located on the opposite outer race. After winding, the monopolar tabs 102 are stacked, and the resulting cell should theoretically have an hourglass-shaped tab 20 on the end as shown in fig. 7 and 8. However, in the actual production process, due to the fluctuation of the winding process and the consistency of the thickness of the materials, if the pole piece 10 designed by the single monopole lug 102 is adopted, the pole lug 20 with the U-shaped end face as shown in fig. 2 will appear after winding, so that the battery cell is scrapped; by adopting the pole piece 10 provided in this embodiment, the projections of the plurality of monopole ears 102 with smaller middle widths in the vertical direction after winding fall into the projections of the head monopole ear 102 and the tail monopole ear 102, so that the fluctuation of the winding process and the error caused by the problem of the thickness consistency of materials are counteracted, the formed pole ear 20 has a more regular end face, the contact area of the plurality of monopole ears 102 is larger, and the winding rate is greatly improved.

On the basis of the above battery cells, this embodiment also provides a square battery as shown in fig. 7 and 8, and the specific structure refers to embodiment 1.

The two tab 20 designs provided in embodiments 1 and 2 enhance the compatibility of the tab 20, correct the dislocation of the tab 20 caused by the fluctuation of the winding process and the problem of the consistency of the thickness of the material, and greatly improve the winding rate. Meanwhile, the lug 20 formed by winding by adopting the two designs has a more regular structure, and the problem that the clamp in the streamline transportation of the collided object of the lug 20 causes scrapped battery cells is avoided.

The above examples are merely illustrative of the preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model, and various modifications and improvements made by those skilled in the art to the technical solution of the present utility model should fall within the protection scope of the present utility model without departing from the design spirit of the present utility model.

Claims (8)

1. A pole piece (10) is characterized in that,

Comprises a pole piece body (101) and a plurality of monopole lugs (102) which are connected with one side edge of the pole piece body (101) in the length direction and are distributed at intervals;

The lengths of the monopole lugs (102) are the same, and the widths are gradually changed in sequence according to the arrangement sequence;

the width gradual change mode of the monopole lug (102) is as follows:

The widths of the monopole ears (102) are sequentially increased and then reduced according to the arrangement sequence, so that the head monopole ear and the tail monopole ear have the same width;

Or (b)

The width of each monopole ear (102) is sequentially reduced and then increased according to the arrangement sequence, so that the head monopole ear and the tail monopole ear have the same width.

2. The pole piece (10) of claim 1, wherein the monopole ear (102) is of a trapezoidal configuration and the monopole ear (102) has a greater width at a location adjacent the pole piece body (101) than at a location remote from the pole piece body (101).

3. The pole piece (10) of claim 1, wherein the spacing width of the plurality of monopolar ears (102) increases or decreases sequentially in a length direction of the pole piece body (101).

4. A battery cell is characterized in that,

The battery cell comprises a pole piece (10) according to any one of claims 1-3;

the pole piece (10) is coiled;

the electrode plate (10) is characterized in that a plurality of monopole lugs (102) are arranged in a lamination mode, the widths of the monopole lugs (102) are sequentially changed layer by layer, and the electrode lugs (20) with hexagonal or hourglass end faces are formed.

5. The cell of claim 4, wherein the cell is square.

6. The cell of claim 4, wherein the tab (20) comprises a positive tab and a negative tab, and the positive tab and the negative tab are located at the same end of the cell.

7. A battery, comprising:

-a housing (30), the housing (30) having two poles;

One or more electrical cores according to any one of claims 5 or 6, said electrical cores being fixed in said housing (30) and a positive tab (20) in said electrical core being connected to one of the poles and a negative tab (20) in said electrical core being connected to the other one of the poles.

8. The battery according to claim 7, characterized in that an insulating layer is provided between the housing (30) and the cells.