CN218957771U

CN218957771U - Battery pole piece and battery core

Info

Publication number: CN218957771U
Application number: CN202222710315.8U
Authority: CN
Inventors: 周槐; 严丽玉
Original assignee: Dongguan Weike Battery Co ltd
Current assignee: Dongguan Weike Battery Co ltd
Priority date: 2022-10-14
Filing date: 2022-10-14
Publication date: 2023-05-02
Anticipated expiration: 2032-10-14

Abstract

The utility model discloses a battery pole piece and a battery core, wherein the battery pole piece comprises a pole piece body and a pole lug, the pole lug is provided with a groove, the pole lug comprises an embedded part corresponding to the shape of the groove, the embedded part is arranged in the groove, a gap is formed between the embedded part and the groove, the groove comprises a groove part and a groove bottom part, the groove part is communicated with a first edge of the pole piece and the groove bottom part, and the width of the groove bottom part is larger than that of the groove part; the width of the bottom of the groove is larger than that of the notch part so as to increase the area of the groove and the lug, thereby increasing the contact area of the lug and the pole piece body, reducing the contact internal resistance of the lug and the pole piece body, improving the temperature rise of the lug and the current density distribution, reducing the local polarization and reducing the lithium precipitation phenomenon in the middle and later period of circulation, and further improving the cycle performance of the battery.

Description

Battery pole piece and battery core

Technical Field

The utility model relates to the technical field of batteries, in particular to a battery pole piece and an electric core.

Background

The lithium ion battery as a novel secondary battery has the advantages of high energy density and power density, high working voltage, light weight, small volume, long cycle life, good safety, environmental protection and the like, and has wide application prospect in the aspects of portable electric appliances, electric tools, large energy storage, electric traffic power sources and the like.

Along with the improvement of the charging speed requirement of the lithium battery in the market, researchers improve and design the battery core of the winding structure to form a structure in which the lug is arranged on the head of the pole piece instead of the traditional structure in which the lug is arranged on the head of the pole piece, and the structure can improve the problem of battery core failure caused by polarization and greatly improve the charge and discharge multiplying power of the battery.

However, during high-current charging, side reactions and current density distribution are caused by temperature rise, and lithium is easy to be separated out in the middle of the cycle at the position close to the edge of the tab, so that the service life of the battery is reduced.

Disclosure of Invention

According to the battery pole piece, the technical problem that lithium is easy to separate out in the middle of circulation at the position close to the edge of the pole lug due to the problem that side reaction and current density are distributed caused by temperature rise when large current is charged in the prior art is solved.

In order to achieve the above purpose, the present utility model adopts the following technical scheme:

the utility model provides a battery pole piece, includes pole piece body and utmost point ear, be provided with the recess on the pole piece body, the utmost point ear include with the embedded portion that the recess shape corresponds, embedded portion set up in the recess, embedded portion with be formed with the clearance between the recess, the recess includes notch portion and tank bottom portion, notch portion intercommunication the first edge of pole piece with the tank bottom portion, just the width of tank bottom portion is greater than the width of notch portion.

Preferably, the bottom of the groove is a reducing groove.

Preferably, the width of the bottom of the groove gradually increases from the first edge of the pole piece to the second edge of the pole piece body.

Preferably, the width of the bottom of the groove gradually decreases from the middle of the bottom of the groove to the second edge of the pole piece body.

Preferably, the projection of the bottom of the groove on the pole piece is one of trapezoid, pentagon, ellipse and fan.

Preferably, the width of the groove bottom is 12-20 mm.

Preferably, the pole piece body is provided with gummed paper at the groove.

Preferably, the tab further includes an exposed portion extending to the outside of the groove, one end of the exposed portion is connected with the embedded portion, and the other end of the exposed portion is used for being connected with a pole of the battery.

Preferably, the pole piece body comprises a current collector and an active material layer, the active material layer is arranged on at least one surface of the current collector, the groove is arranged on the active material layer, and the bottom wall of the groove is the current collector.

Another object of the utility model is: the battery cell comprises a positive electrode plate, a negative electrode plate and a diaphragm arranged between the positive electrode plate and the negative electrode plate, wherein the positive electrode plate and/or the negative electrode plate is a battery plate described in the specification.

Compared with the prior art, the utility model has the beneficial effects that:

the utility model provides a battery pole piece, use through the cooperation of pole piece body and utmost point ear, be provided with the recess on the pole piece body, the utmost point ear is including setting up the embedded portion in the recess, embedded portion is corresponding with the shape of recess, the recess includes notch portion and tank bottom portion, the width of tank bottom portion is greater than notch portion, thereby increase the area of recess and utmost point ear, thereby increase the area of contact of utmost point ear and pole piece body, reduce the contact internal resistance of utmost point ear and pole piece body, reach and improve utmost point ear temperature rise and current density distribution, reduce local polarization, reduce the lithium phenomenon that separates of middle and later stages in the circulation, thereby promote the cycle performance of battery.

Additional aspects and advantages of the utility model will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the utility model, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.

Fig. 1 is a schematic structural view of a pole piece body according to the present utility model.

Fig. 2 is another schematic structural view of the pole piece body of the present utility model.

Fig. 3 is an enlarged schematic view of the structure at a in fig. 2.

Fig. 4 is a schematic view of another structure of the pole piece body of the present utility model.

Fig. 5 is an enlarged schematic view of the structure at B in fig. 4.

Reference numerals:

100. a battery pole piece;

10. a pole piece body; 11. a groove; 111. a slot part; 112. a groove bottom; 12. a first edge of the pole piece body; 13. a second edge of the pole piece body; 14. a current collector; 15. an active material layer; 16. a gap;

20. a tab; 21. an embedded part; 22. an exposed portion;

30. glue paper;

a. the width of the slot part; b. the length of the slot part; c. width of the bottom of the groove; d. length of the bottom of the trough.

Detailed Description

The following description of the technical solutions in the embodiments of the present utility model will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Referring to fig. 1 to 5, an embodiment of the utility model provides a battery pole piece, which comprises a pole piece body 10 and a pole lug 20, wherein a groove 11 is arranged on the pole piece body 10, the pole lug 20 comprises an embedded part 21 corresponding to the shape of the groove 11, the embedded part 21 is arranged in the groove 11, a gap is formed between the embedded part 21 and the groove 11, the groove 11 comprises a groove part 111 and a groove bottom 112, the groove part 111 is communicated with a first edge of the pole piece and the groove bottom 112, and the width c of the groove bottom 112 is larger than the width a of the groove part 111.

Compared with the prior art, the embodiment of the utility model provides a battery pole piece, through the cooperation use of a pole piece body 10 and a pole lug 20, the pole lug 20 is provided with a groove 11, the pole lug 20 comprises an embedded part 21 arranged in the groove 11, the embedded part 21 corresponds to the shape of the groove 11, the groove 11 comprises a groove part 111 and a groove bottom 112, the width c of the groove bottom 112 is larger than that of the groove part 111, so that the area of the groove 11 and the pole lug 20 is increased, the contact area of the pole lug 20 and the pole piece body 10 is increased, the contact internal resistance of the pole lug 20 and the pole piece body 10 is reduced, the temperature rise and the current density distribution of the pole lug 20 are improved, the local polarization is reduced, the lithium precipitation phenomenon in the middle and later period of the cycle is reduced, and the cycle performance of the battery is improved.

The specific position and size of the groove 11 on the pole piece body 10 are determined, and the active material on the pole piece body 10 at the position of the groove 11 is cleaned by using a laser cleaning instrument.

The projection of the notch 111 on the pole piece body 10 is rectangular or trapezoidal.

It should be noted that the gap may be filled with an insulating adhesive, and the top surface of the insulating adhesive is displaced at the same level as the surface of the pole piece body 10. The surface flatness of the pole piece is effectively improved, and the abnormal risks of uneven lithium separation and the like of interface contact caused by pressurization formation of the battery cell are reduced. Specifically, the insulating glue is hot melt glue or SBR glue solution.

In this embodiment, the groove bottom 112 is a reducing groove. The reducing grooves are arranged, so that the positions of the groove bottom 112 have different widths, and the widths of the positions of the groove bottom 112 can be set according to actual requirements when the reducing groove is used.

In this embodiment, the width c of the groove bottom 112 gradually increases from the first edge of the pole piece to the second edge 13 of the pole piece body. When the width c of the groove bottom 112 gradually increases from the first edge of the pole piece to the second edge 13 of the pole piece body, the area of the groove bottom 112 is effectively increased, so that the area of the groove 11 is increased, and the contact area between the tab 20 and the pole piece body 10 is increased.

In this embodiment, the width c of the groove bottom 112 gradually decreases from the middle of the groove bottom 112 toward the second edge 13 of the pole piece body. When the width c of the slot bottom 112 gradually increases from the first edge of the pole piece toward the middle of the slot bottom 112 and gradually decreases from the middle of the slot bottom 112 toward the second edge 13 of the pole piece body, in order to increase the area of the groove 11, it is necessary to ensure that the minimum value of the width c of the slot bottom 112 is greater than the maximum value of the width a of the notch 111.

In this embodiment, the projection of the bottom 112 of the groove on the pole piece is one of trapezoid, pentagon, ellipse and fan. The shape of the groove bottom 112 is effectively increased, and the groove bottom can be arranged according to actual requirements when in use.

In this embodiment, the width c of the groove bottom 112 is 12 to 20mm. Specifically, the width c of the groove bottom 112 is 12-14 mm, 14-16 mm, 16-18 mm or 18-20 mm, when the width c of the groove bottom 112 is smaller than 12mm, the width c of the groove bottom 112 is smaller, so that the area of the groove 11 becomes smaller, and the contact area between the tab 20 and the pole piece body 10 cannot be increased; when the width c of the groove bottom 112 is greater than 20mm, the width c of the groove bottom 112 is greater, so that the groove 11 needs to occupy more area of the pole piece body 10, resulting in less coated active material and affecting the energy density of the battery.

The length d of the groove bottom 112 is 12 to 18mm, specifically, the length d of the groove bottom 112 is 12 to 14mm, 14 to 16mm or 16 to 18mm, and preferably, the length d of the groove bottom 112 is 15mm.

The length b of the notch portion 111 is 12 to 18mm, specifically, the length b of the notch portion 111 is 12 to 14mm, 14 to 16mm or 16 to 18mm, and preferably the length b of the notch portion 111 is 15mm.

The width a of the notch portion 111 is 9 to 15mm, specifically, the width a of the notch portion 111 is 9 to 11mm, 11 to 13mm or 13 to 15mm, and preferably the width a of the notch portion 111 is 12mm.

In this embodiment, the pole piece body 10 is provided with a piece of gummed paper 30 at the recess 11. Through the setting of gummed paper 30, gummed paper 30 sets up on pole piece body 10 for cover recess 11, effectually prevent that the burr from appearing after the tab 20 welding from penetrating the diaphragm.

In this embodiment, the tab 20 further includes an exposed portion 22 extending to the outside of the groove 11, one end of the exposed portion 22 is connected to the embedded portion 21, and the other end of the exposed portion 22 is used for connection with a post of a battery. Through the setting of exposed portion 22, the one end of exposed portion 22 is connected with embedded portion 21, and the other end of exposed portion 22 is connected with the utmost point post of battery, the effectual connection of realizing utmost point ear 20 and utmost point post.

In this embodiment, the pole piece body 10 includes a current collector 14 and an active material layer 15, the active material layer 15 is disposed on at least one surface of the current collector 14, the groove 11 is disposed on the active material layer 15, and the bottom wall of the groove 11 is the current collector 14. Through the cooperation of current collector 14, active material layer 15 adheres to at least one surface of current collector 14, and recess 11 sets up on active material layer 15, and effectual embedded portion 21 that makes tab 20 is connected with pole piece body 10.

The two ends of the pole piece body 10 are provided with empty foil areas. The current collector 14 is made of copper foil or aluminum foil.

Another embodiment of the present utility model provides an electrical core, including a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate, where the positive electrode plate and/or the negative electrode plate is the battery electrode plate 100 described in the foregoing embodiments.

Compared with the prior art, the battery cell provided by the other embodiment of the utility model has the advantages that through the matched use of the positive pole piece, the negative pole piece and the diaphragm, the diaphragm is arranged between the positive pole piece and the negative pole piece, the positive pole piece and/or the negative pole piece are the battery pole piece 100 in the embodiment, the battery pole piece 100 is provided with the groove 11, the groove 11 comprises the groove part 111 and the groove bottom 112, the width c of the groove bottom 112 is larger than the groove part 111, so that the areas of the groove 11 and the tab 20 are increased, the contact area of the tab 20 and the tab body 10 is increased, the contact internal resistance of the tab 20 and the tab body 10 is reduced, the temperature rise and the current density distribution of the tab 20 are improved, the local polarization is reduced, the lithium precipitation phenomenon in the middle and later period of the cycle is reduced, and the cycle performance of the battery is improved.

The positive electrode plate comprises a positive electrode current collector 14 and a positive electrode active material layer 15, and the positive electrode active material layer 15 is coated on the surface of the positive electrode current collector 14; the positive electrode current collector 14 includes a positive electrode coating region coated with the positive electrode active material layer 15 and a positive electrode tab 20 connected to the positive electrode coating region, the positive electrode tab 20 not being coated with the positive electrode active material layer 15. Taking a lithium ion battery as an example, the material of the positive electrode current collector 14 may be aluminum, the positive electrode active material layer 15 includes a positive electrode active material, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative electrode plate comprises a negative electrode current collector 14 and a negative electrode active material layer 15, and the negative electrode active material layer 15 is coated on the surface of the negative electrode current collector 14; the anode current collector 14 includes an anode coating region coated with the anode active material layer 15 and an anode tab 20 connected to the anode coating region, the anode tab 20 not being coated with the anode active material layer 15. The material of the anode current collector 14 may be copper, the anode active material layer 15 includes an anode active material, and the anode active material may be carbon, silicon, or the like. The material of the separator may be PP (polypropylene) or PE (polyethylene), etc.

It will be evident to those skilled in the art that the utility model is not limited to the details of the foregoing illustrative embodiments, and that the present utility model may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the utility model being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. The utility model provides a battery pole piece, its characterized in that includes pole piece body (10) and utmost point ear (20), be provided with recess (11) on pole piece body (10), utmost point ear (20) include with embedded portion (21) that recess (11) shape corresponds, embedded portion (21) set up in recess (11), embedded portion (21) with be formed with the clearance between recess (11), recess (11) include notch portion (111) and tank bottom portion (112), notch portion (111) intercommunication the first edge of pole piece with tank bottom portion (112), just width (c) of tank bottom portion (112) are greater than width (a) of notch portion (111).

2. A battery pole piece according to claim 1, characterized in that the groove bottom (112) is a reducing groove.

3. A battery pole piece according to claim 2, characterized in that the width (c) of the bottom (112) of the groove becomes progressively larger from the first edge of the pole piece towards the second edge (13) of the pole piece body.

4. A battery pole piece according to claim 3, characterized in that the width (c) of the bottom (112) of the groove tapers from the middle of the bottom (112) of the groove towards the second edge (13) of the pole piece body.

5. A battery pole piece according to claim 2, characterized in that the projection of the bottom (112) of the groove onto the pole piece has the shape of one of a trapezoid, a pentagon, an ellipse, a sector.

6. A battery pole piece according to any of claims 1-5, characterized in that the width (c) of the groove bottom (112) is 12-20 mm.

7. A battery pole piece according to claim 1, characterized in that the pole piece body (10) is provided with a gummed paper (30) at the recess (11).

8. A battery pole piece according to claim 1, wherein the tab (20) further comprises an exposed portion (22) extending to the outside of the recess (11), one end of the exposed portion (22) is connected to the embedded portion (21), and the other end of the exposed portion (22) is used for connection to a pole of a battery.

9. A battery pole piece according to claim 1, wherein the pole piece body (10) comprises a current collector (14) and an active material layer (15), the active material layer (15) is disposed on at least one surface of the current collector (14), the groove (11) is disposed on the active material layer (15), and a bottom wall of the groove (11) is the current collector (14).

10. An electric core, characterized by comprising a positive pole piece, a negative pole piece and a diaphragm arranged between the positive pole piece and the negative pole piece, wherein the positive pole piece and/or the negative pole piece is the battery pole piece according to any one of claims 1-9.