Pole piece, battery cell and battery

Abstract

The utility model discloses a pole piece, a battery cell and a battery, and relates to the technical field of new energy. The pole piece comprises a current collector and an active material layer, wherein the current collector is provided with a main body part and a tab part; the active substance layer comprises a first active part and a second active part which are connected with each other, the main body part is coated with the first active part, part of the tab part is coated with the second active part, and the thickness of the second active part is smaller than that of the first active part; the pole piece further comprises insulating gummed paper, part of the insulating gummed paper is attached to the second active part, and the rest of the insulating gummed paper is attached to the area, not coated with the second active part, of the tab part. According to the pole piece disclosed by the utility model, by arranging the second active part which is slightly thinner, the defect of foil leakage can be avoided while the thickness of the pole piece is not influenced.

Description

TECHNICAL FIELD

[0001] The utility model relates to new energy technology field especially, relate to a kind of pole piece, electric core and battery. BACKGROUND

[0002] The electric core of lithium battery is made of positive and negative pole piece and diaphragm by laminating or winding process, and the pole piece is made by coating active material slurry on metal foil as current collector, generally, in order to lead out the electrode of battery, it also needs to set tab part on the pole piece. The pole piece generally reserves metal foil area outside coating area, and the metal foil can form tab part after die cutting.

[0003] In related technology, in order to avoid short circuit problem caused by tab part and opposite pole piece lap joint, therefore, it is necessary to attach insulating adhesive tape on tab part. However, in the process of attaching insulating adhesive tape to tab part, if the insulating adhesive tape is attached only on the tab part, due to cutting tolerance of insulating adhesive tape, error of attaching process and other reasons, gap exposing tab part foil will inevitably appear between insulating adhesive tape and coating area of pole piece, and electrolyte is easy to penetrate into tab part foil from the gap to corrode tab part. If the insulating adhesive tape is partially attached to coating area and the rest is attached to tab part, although the gap problem is overcome, it is easy to cause the thickness of pole piece to be too thick, which affects the energy density of electric core. SUMMARY

[0004] The utility model aims at at least one of the technical problems existing in prior art. For this purpose, the utility model provides a kind of pole piece, can avoid the defect of leakage foil while not affecting the thickness of pole piece.

[0005] The utility model further provides another kind of pole piece.

[0006] The utility model further provides a kind of electric core with the above-mentioned pole piece.

[0007] The utility model further provides a kind of battery with the above-mentioned electric core.

[0008] According to the pole piece of the first aspect embodiment of the utility model, comprising:

[0009] Current collector, the current collector has main body part and tab part;

[0010] Active material layer, the active material layer includes mutually linked first active part and second active part, the first active part is coated on the main body part, and the second active part is coated on part of the tab part, and the thickness of the second active part is less than the thickness of the first active part;

[0011] The pole piece further comprises an insulating adhesive tape, and the insulating adhesive tape is partially attached to the second active part and attached to a region of the tab part which is not coated with the second active part.

[0012] The pole piece has at least the following beneficial effects:

[0013] The second active part is formed on the tab part, and the thickness of the second active part is controlled to form a stepped structure with the first active part, so that the insulating adhesive tape can be partially attached to the second active part. Since the thickness of the second active part is small, the attachment of the insulating adhesive tape to the second active part does not affect the overall thickness of the pole piece, thereby avoiding affecting the energy density of the battery. In addition, even if there is an attachment error in the attachment of the insulating adhesive tape, so that the end of the insulating adhesive tape cannot be connected to the first active part and a gap is formed, the gap will not expose the empty foil region of the tab part, but will expose the second active part. The second active part can separate the foil of the tab part from the electrolyte, thereby avoiding direct contact between the foil of the tab part and the electrolyte, and preventing corrosion, thereby improving the service life of the battery.

[0014] According to some embodiments of the present application, the edge of the main body part defines a first groove, and the tab part is at least partially located in the first groove and connected to the main body part.

[0015] According to some embodiments of the present application, the edge of the main body part further defines a second groove, and the second groove is used to avoid the tab part of the opposite pole piece.

[0016] According to some embodiments of the present application, the thickness difference between the first active part and the second active part is 20 microns to 50 microns.

[0017] According to some embodiments of the present application, along the arrangement direction of the first active part and the second active part, the length of the insulating adhesive tape is 0.6 mm to 2.4 mm, and the length of the second active part is 0.3 mm to 1.2 mm.

[0018] The pole piece according to the second aspect of the present application comprises:

[0019] A current collector has a main body part and a tab part;

[0020] An active material layer comprises a first active part and a second active part connected to each other, the second active part is coated on the edge of the main body part for connecting the tab part, the first active part is coated on the remaining part of the main body part, and the thickness of the second active part is less than the thickness of the first active part.

[0021] The pole piece further comprises an insulating adhesive paper, and the insulating adhesive paper is partially attached to the second active part and the rest is attached to the pole lug part.

[0022] The battery according to the fourth aspect of the present application comprises the battery cell according to any one of the above embodiments.

[0023] According to some embodiments of the present application, the main body part of the pole piece defines a first groove and a second groove, the diaphragm has a third groove and a fourth groove, the pole piece comprises a positive pole piece and a negative pole piece, the first groove of the positive pole piece is arranged corresponding to the second groove of the negative pole piece and is communicated through the third groove of the diaphragm, and the second groove of the positive pole piece is arranged corresponding to the first groove of the negative pole piece and is communicated through the fourth groove of the diaphragm.

[0024] According to some embodiments of the present application, the pole piece further comprises a pole lug part connected with the main body part, and the pole lug parts of two adjacent pole pieces of the same type are electrically connected through the third groove or the fourth groove.

[0025] The battery according to the fourth aspect of the present application comprises the battery cell according to any one of the above embodiments.

[0026] Additional aspects and advantages of the present application will be given in part in the following description, become apparent from the following description, or be understood by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0027] The present application will be further described below in combination with the drawings and embodiments, wherein:

[0028] Figure 1 A schematic view of the insulating adhesive paper attached to the pole lug part in the related art;

[0029] Figure 2 A structure schematic view of the pole piece according to the embodiments of the present application;

[0030] Figure 3 A structure schematic view of the insulating adhesive paper attached to the pole lug part and the second active part according to the embodiments of the present application;

[0031] Figure 4 A structure schematic view of the insulating adhesive paper attached to the pole lug part and the second active part according to the embodiments of the present application (with gaps);

[0032] Figure 5 A manufacturing flow chart of the pole piece according to the embodiments of the present application;

[0033] Figure 6Manufacturing flow chart of the pole piece of another embodiment of the utility model;

[0034] Figure 7 Manufacturing flow chart of the pole piece of another embodiment of the utility model;

[0035] Figure 8 Structure schematic view of the positive pole piece, the diaphragm and the negative pole piece of the embodiment of the utility model.

[0036] Reference signs:

[0037] Pole piece 10, positive pole piece 11, negative pole piece 12, diaphragm 20, third groove 21, fourth groove 22;

[0038] Current collector 100, main body part 110, first groove 111, second groove 112, tab part 120;

[0039] Active material layer 200, first active part 210, second active part 220;

[0040] Insulating adhesive paper 300;

[0041] Gap 400;

[0042] Removed area 500; DETAILED DESCRIPTION

[0043] The embodiments of the utility model are described in detail below, examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, only for explaining the utility model, and cannot be understood as limiting the utility model.

[0044] In the description of the utility model, it is understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as limiting the utility model.

[0045] In the description of the utility model, the meaning of several is more than one, the meaning of multiple is more than two, greater than, less than, more than, etc. is not included in the number, above, below, etc. is included in the number. If it is described to the first, the second is only used for distinguishing the technical features for the purpose, and therefore cannot be understood as indicating or implying the relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0046] In the description of the utility model, unless otherwise expressly limited, the words such as setting, installing, connecting should be understood broadly, and the skilled in the art can determine the specific meaning of the above words in the utility model according to the specific content of the technical scheme.

[0047] In the description of the utility model, the description of the reference terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0048] The cell of the lithium battery is made by laminating or winding the positive and negative electrode sheets and the separator, and the electrode sheet is made by coating the active material slurry on the metal foil as the current collector. Generally, in order to lead out the electrode of the battery, the tab part needs to be provided on the electrode sheet. The electrode sheet generally has a metal foil area reserved outside the coating area, and the metal foil can form the tab part after die cutting.

[0049] In the related art, as shown in Figure 1 In order to avoid the short circuit problem caused by the overlap of the tab part 120 and the hetero electrode sheet 10, the insulating adhesive tape 300 needs to be attached to the tab part 120. However, in the process of attaching the insulating adhesive tape 300 to the tab part 120, if the insulating adhesive tape 300 is only attached to the tab part 120, due to the cutting tolerance of the insulating adhesive tape 300, the error of the attachment process and other reasons, the gap 400 of the foil material of the tab part 120 will inevitably appear between the insulating adhesive tape 300 and the active material layer 200 of the electrode sheet 10, and the electrolyte is easy to penetrate into the foil material of the tab part 120 from the gap 400 to corrode the tab part 120; if the insulating adhesive tape 300 is partially attached to the active material layer 200 and the remaining part is attached to the tab part 120, although the problem of easy generation of the gap 400 is overcome, the thickness of the electrode sheet 10 is easy to be too thick, which affects the energy density of the cell.

[0050] To solve the above problems, as shown in Figures 2 to 4As shown, the first aspect of the present application proposes an electrode sheet 10, which includes a current collector 100 and an active material layer 200. It should be noted that the electrode sheet 10 can be a positive electrode sheet 11 or a negative electrode sheet 12. The current collector 100 is made of a metal foil or a composite foil. Its main function is to collect the current generated by the active material layer 200 and transmit it to the external circuit through the tab 120. For the positive electrode sheet 11, aluminum foil is often used as the material of the positive electrode current collector 100. For the negative electrode sheet 12, copper foil is often used as the material of the negative electrode current collector 100. The active material layer 200 is used to undergo electrochemical reaction with the electrolyte to generate current. The active material of the positive electrode sheet 11 often includes lithium manganese iron phosphate, lithium cobaltate and other materials. The active material of the negative electrode sheet 12 often includes graphite and other materials. The active material is coated on one side or both sides of the current collector 100 by coating and other processes, and the electrode sheet 10 is formed after baking, compaction and other processes.

[0051] Specifically, in the present application, the current collector 100 has a main body part 110 and a tab part 120. As shown, Figures 2 to 4 The main body part 110 and the tab part 120 of the current collector 100 are formed by cutting. The main body part 110 and the tab part 120 are originally a whole foil. After cutting, the main body part 110 and the tab part 120 are formed. One side edge of the tab part 120 is connected to the main body part 110, and the other three side edges are disconnected from the main body part 110. The cutting process can be die cutting or laser cutting. The active material layer 200 includes a first active part 210 and a second active part 220. The first active part 210 is coated on the main body part 110, and the second active part 220 is coated on the tab part 120. It should be noted that the second active part 220 does not cover the entire tab part 120, but only covers part of the area where the tab part 120 connects to the main body part 110.

[0052] It should be noted that the first active part 210 and the second active part 220 have a thickness difference, wherein the thickness of the second active part 220 is less than the thickness of the first active part 210. In some embodiments, the first active part 210 and the second active part 220 are formed by coating respectively. When coating, the thickness of the second active part 220 is less than the thickness of the first active part 210. In other embodiments, the first active part 210 and the second active part 220 are equal in thickness when coating, and then the thickness of the second active part 220 is thinned to a certain range by laser cleaning process.

[0053] To avoid short circuit caused by the contact between the tab portion 120 and the female tab 10, the tab 10 further comprises an insulating adhesive paper 300. It should be noted that, unlike the prior art in which the insulating adhesive paper 300 is directly attached to the foil-free area of the tab portion 120, in the embodiment of the first aspect of the present application, the insulating adhesive paper 300 is partially attached to the second active portion 220 and the remaining part is attached to the area of the tab portion 120 which is not coated with the second active portion 220 (i.e. the foil-free area of the tab portion 120).

[0054] Based on the above, in the embodiment of the first aspect of the present application, the second active portion 220 is formed on the tab portion 120, and the thickness of the second active portion 220 is controlled to form a stepped structure with the first active portion 210, so that the insulating adhesive paper 300 can be partially attached to the second active portion 220. Since the thickness of the second active portion 220 is small, the attachment of the insulating adhesive paper 300 to the second active portion 220 will not affect the overall thickness of the tab 10, thereby avoiding affecting the energy density of the battery. In addition, even if there is an attachment error in the attachment process of the insulating adhesive paper 300, so that the end of the insulating adhesive paper 300 cannot be connected to the first active portion 210 to form a gap 400 (as shown in Figure 4 The second active portion 220 can separate the foil of the tab portion 120 and the electrolyte, thereby avoiding direct contact between the foil of the tab portion 120 and the electrolyte to cause corrosion, thereby improving the service life of the battery.

[0055] In some embodiments, as shown in Figure 2 and Figure 3 The current collector 100 is cut to form the main body portion 110 and the tab portion 120, wherein the edge of the main body portion 110 defines a first recess 111, and the tab portion 120 is at least partially located in the first recess 111 and connected to the main body portion 110. Further, the edge of the main body portion 110 further defines a second recess 112, which is used to avoid the tab portion 120 of the female tab 10. It can be understood that when the tabs 10 are stacked to form a battery cell, adjacent tabs 10 have opposite polarities and are separated by a separator 20 to avoid short circuit. The tabs with the same polarity need to be welded into an integrated structure, and then an external pole or the like is connected to output or input current. When stacking, as shown in Figure 8 The first recess 111 of the positive tab 11 is arranged in alignment with the second recess 112 of the negative tab 12, and the second recess 112 of the positive tab 11 is arranged in alignment with the first recess 111 of the negative tab 12, so that the positive tabs of two adjacent positive tabs 11 can be connected through the second recess 112 of the negative tab 12, and the negative tabs of two adjacent negative tabs 12 can be connected through the second recess 112 of the positive tab 11.

[0056] In addition, in the embodiment, the first groove 111 is cut out at the edge of the body part 110, so that the tab part 120 can be at least partially accommodated in the first groove 111, thereby avoiding the tab part 120 from occupying too much space in the length direction of the pole piece 10, and facilitating to improve the energy density of the battery. In addition, as shown in Figure 2 the body part 110 on both sides of the first groove 111 and the body part 110 on both sides of the second groove 112 are coated with active substances, thereby further improving the active substance content of the battery cell and facilitating to improve the energy density of the battery.

[0057] In some embodiments, the second active part 220 is formed by a laser thinning process, and the thickness difference between the first active part 210 and the second active part 220 is 20 microns to 50 microns, that is, the laser thinning needs to be thinned by 20 microns to 50 microns. The thickness of the insulating adhesive paper 300 needs to be controlled within the range of 20 microns to 50 microns, and preferably, the thickness of the insulating adhesive paper 300 is less than the depth of the laser thinning, so that after the insulating adhesive paper 300 is attached to the second active part 220, the top of the insulating adhesive paper 300 is not higher than the surface of the first active part 210, so as to ensure the flatness of the surface of the pole piece 10. The insulating adhesive paper 300 includes a substrate and an adhesive layer, and the substrate includes one or more of thermoplastic polyester, polyethylene, polypropylene, and polyvinyl chloride; and the adhesive layer includes one or more of acrylic resin, polycarbonate, polyurethane, and rubber.

[0058] In some embodiments, the length of the insulating adhesive paper 300 is 0.6 millimeters to 2.4 millimeters along the arrangement direction of the first active part 210 and the second active part 220, that is, the length direction of the pole piece 10 as shown in Figure 3 the length of the second active part 220 is 0.3 millimeters to 1.2 millimeters.

[0059] Based on the above, referring to Figure 5 the manufacturing process of the pole piece 10 of the first aspect embodiment of the present application has the following steps:

[0060] Step S10, referring to Figure 5 a, the active substance layer 200 is coated on the current collector 100;

[0061] Step S20, referring to Figure 5 b, the active substance layer 200 is partially removed by laser cleaning to form the second active part 220 and the first active part 210.

[0062] Step S30, the pole piece 10 is die-cut, and the region to be removed as shown in Figure 5 c is the region 500 removed by die-cutting, and thus, after die-cutting, the pole piece 10 as shown inFigure 5 The first groove 111 and the second groove 112 are die-cut, and the tab 120 is also die-cut in the first groove 111.

[0063] Step S40, referring to Figure 5 e, an insulating tape 300 is attached on the tab 120, and the insulating tape 300 is partially located on the second active part 220 and partially located on the empty foil area of the tab 120.

[0064] It can be understood that in other embodiments, as Figure 6 shown, the length of the tab 120 is longer, so that the width of the coating area is controlled to be smaller than the width of the current collector 100 in step S10, and the coating area is also formed with an empty foil area on one side, and then the above-mentioned cleaning and die-cutting steps are performed.

[0065] Based on the technical concept that the insulating tape 300 is partially attached to the second active part 220 with a slightly thinner thickness, the second aspect embodiment of the present application further proposes another pole piece 10, as Figure 7 shown, the pole piece 10 includes a current collector 100 and an active material layer 200, the current collector 100 has a main body part 110 and a tab 120, the active material layer 200 includes a first active part 210 and a second active part 220 which are connected to each other, the second active part 220 is coated on the edge of the main body part 110 for connecting with the tab 120, the first active part 210 is coated on the remaining part of the main body part 110, and the thickness of the second active part 220 is smaller than the thickness of the first active part 210. The pole piece 10 further includes an insulating tape 300, the insulating tape 300 is partially attached to the second active part 220 and the remaining part is attached to the tab 120.

[0066] It should be noted that in the pole piece 10 of the second aspect embodiment of the present application, the second active part 220 is formed on the main body part 110. Specifically, the manufacturing process of the pole piece 10 has the following steps:

[0067] Step S10, coating the active material layer 200 on the current collector 100; wherein the width of the active material layer 200 is smaller than the width of the current collector 100, so that an empty foil area is formed on one side of the active material layer 200;

[0068] Step S20, thinning the active material layer 200 in the set area by laser cleaning, and the thinned active material layer 200 forms the second active part 220, and the unthinned part forms the first active part 210.

[0069] Step S30, die-cutting the pole piece 10, as Figure 7 c, the area to be removed by die-cutting is 500, so that after die-cutting, as Figure 7The tab portion 120 and the second groove 112 are die-cut.

[0070] In step S40, the insulating adhesive tape 300 is attached on the tab portion 120, and the insulating adhesive tape 300 is partially located on the second active portion 220 and partially located on the tab portion 120.

[0071] It can be understood that, compared with the tab 10 in the first aspect embodiment, the tab 10 in the second aspect embodiment has a smaller cleaning area and die-cut area in the manufacturing process, thereby reducing the waste rate and saving the production cost of the tab 10.

[0072] The third aspect embodiment of the present application further provides an electrode core, which can be understood as including the separator 20 and the tab 10 as described in any of the above embodiments. The electrode core can be a jelly-roll electrode core, which further includes a plurality of positive tabs 11, a plurality of negative tabs 12, and the separator 20. The positive tabs 11 and the negative tabs 12 are alternately and layeringly arranged, and the separator 20 is arranged between any positive tab 11 and the adjacent negative tab 12 to avoid the positive tab 11 and the negative tab 12 from being in contact and short-circuiting. The electrode core can also be a jelly-roll electrode core, which includes the positive tab 11, the negative tab 12, and the separator 20 in the form of a material belt. After the positive tab 11, the negative tab 12, and the separator 20 are layered, the jelly-roll electrode core is formed by winding through a winding device.

[0073] In some embodiments, as shown in the jelly-roll electrode core as shown in Figure 8 In some embodiments, as shown in the jelly-roll electrode core as shown in

[0074] The fourth aspect embodiment of the present application also provides a battery, which comprises the battery cell mentioned in any one of the above embodiments.

[0075] The embodiments of the utility model are explained in detail above in combination with the drawings, but the utility model is not limited to the above-mentioned embodiments, and various changes can be made within the knowledge range of the ordinary skill in the art without departing from the purpose of the utility model. In addition, the embodiments and the features in the embodiments of the utility model can be combined with each other without conflict.

Claims

1. A pole piece characterized by, The collector has a main body and a tab; The active material layer includes a first active part and a second active part, the first active part is coated on the main body, and the second active part is coated on part of the tab, and the thickness of the second active part is less than that of the first active part; The tab further includes an insulating tape, and the insulating tape is partially attached to the second active part and the remaining part is attached to the tab. The edge of the main body defines a first groove, and the tab is at least partially located in the first groove and connected with the main body.

2. The pole piece of claim 1, wherein The edge of the main body further defines a second groove for avoiding the tab of the opposite tab.

3. The pole piece of claim 2, wherein The thickness difference between the first active part and the second active part is 20 microns to 50 microns.

4. The pole piece of claim 1, wherein The length of the insulating tape along the setting direction of the first active part and the second active part is 0.6 mm to 2.4 mm, and the length of the second active part is 0.3 mm to 1.2 mm.

5. The pole piece of claim 1, wherein The collector has a main body and a tab; 6. A pole piece characterized by, The active material layer includes a first active part and a second active part, the first active part is coated on the main body, and the second active part is coated on part of the tab, and the thickness of the second active part is less than that of the first active part; The tab further includes an insulating tape, and the insulating tape is partially attached to the second active part and the remaining part is attached to the tab. The separator and the tab as claimed in any one of claims 1 to 6 are laminated or wound to form the battery cell. The main body of the tab defines a first groove and a second groove, the separator has a third groove and a fourth groove, the tab includes a positive tab and a negative tab, the first groove of the positive tab is arranged corresponding to the second groove of the negative tab and is communicated through the third groove of the separator, and the second groove of the positive tab is arranged corresponding to the first groove of the negative tab and is communicated through the fourth groove of the separator.

7. An electric cell, characterized by The tab further includes a tab connected with the main body, and the tabs of two adjacent same tabs are electrically connected through the third groove or the fourth groove.

8. The electric cell of claim 7, wherein, The battery cell as claimed in any one of claims 7 to 9 is included.

9. The electric cell of claim 8, wherein, ​ 10. A battery characterized by ​

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