阅读说明：本技术 一种锂离子电池极片及锂离子电池 (Lithium ion battery pole piece and lithium ion battery ) 是由 江文锋 敖志勇 王进 陈凯翔 刘超 于 2020-06-30 设计创作，主要内容包括：本发明提供了一种锂离子电池极片,主要解决极芯内产生的气体能及时排出的问题,包括集流体和涂覆在集流体上的涂层,其特征在于,所述涂层上设有凹槽,所述凹槽沿所述极片长度方向设置,所述涂层上还设有与所述凹槽成预定夹角的排气槽,所述排气槽用于将所述凹槽与所述极片的外部连通。以便于产生的气体可以经过凹槽后从排气槽排到极片外部,形成排气通道,可以将电解液产生的气体及时排出。(The invention provides a lithium ion battery pole piece, which mainly solves the problem that gas generated in a pole core can be discharged in time and comprises a current collector and a coating coated on the current collector. So that the generated gas can be discharged to the outside of the pole piece from the exhaust groove after passing through the groove, an exhaust channel is formed, and the gas generated by the electrolyte can be discharged in time.)

1. The utility model provides a lithium ion battery pole piece, includes the mass flow body and coats the coating on the mass flow body, its characterized in that, be equipped with the recess on the coating, the recess is followed pole piece length direction sets up, still be equipped with on the coating with the recess becomes the exhaust duct of predetermined contained angle, the exhaust duct be used for with the recess with the outside intercommunication of pole piece.

2. The lithium ion battery pole piece of claim 1, wherein the exhaust grooves comprise a first exhaust groove and a second exhaust groove, wherein an air inlet of the first exhaust groove is connected with one side of the pole piece, an air outlet of the first exhaust groove is connected with one side of the groove, the other side of the groove is connected with an air inlet of the second exhaust groove, and an air outlet of the second exhaust groove is connected with the other side of the pole piece.

3. The lithium ion battery pole piece of claim 1, wherein the exhaust grooves comprise a first exhaust groove, a second exhaust groove and a third exhaust groove, wherein an air inlet of the first exhaust groove is connected with one side of the pole piece, an air outlet of the first exhaust groove is connected with one side of a first groove, the other side of the first groove is connected with an air inlet of the second exhaust groove, an air outlet of the second exhaust groove is connected with one side of a second groove, the other side of the second groove is connected with an air inlet of the third exhaust groove, and an air outlet of the third exhaust groove is connected with the other side of the pole piece.

4. The lithium ion battery pole piece of claim 1, wherein the at least one groove.

5. The lithium ion battery pole piece of claim 1, wherein the lithium ion battery pole piece has a thickness L₁The depth of the groove is L₂ ，L₂The value range is as follows: 1/100L₁＜L₂＜1/10L₁。

6. As claimed in claim 1The lithium ion battery pole piece is characterized in that the width of the groove is L₃，L₃The value range is as follows: coating width x 1/10 < L₃< coating width x 1/3.

7. The lithium ion battery pole piece of claim 1, wherein the number of the vent grooves is plural, and the plurality of vent grooves are arranged in a staggered manner.

8. The lithium ion battery pole piece of claim 1, wherein the vent channel has a depth L₈，L₈The value range is as follows: 1/10L₂＜L₈＜1/2L₂。

9. The lithium ion battery pole piece of claim 1, wherein the width of the vent channel is L₉，L₉The value range is as follows: l is more than 5mm₉＜200mm。

10. A lithium ion battery comprising the lithium ion battery pole piece of claims 1-9.

Technical Field

The invention relates to the field of lithium ion battery pole pieces, in particular to a lithium ion battery pole piece and a lithium ion battery.

Background

For a winding type lithium ion battery, the thickness of the positive and negative pole pieces is basically in a uniform design at present, and the lithium precipitation in the middle of the pole core is relatively serious and the high surface density is particularly obvious in the process of carrying out high-magnification 1C/1C circulation; the main problem is that in the process of high-rate circulation, electrolyte in the middle of the pole core and gas generated by the electrolyte are expelled due to the expansion of the material, so that local polarization is large, and lithium precipitation and deformation are caused.

Disclosure of Invention

The invention aims to improve the battery performance, prevent the electrolyte between the positive and negative electrode materials in the lithium ion battery pole core from being extruded in the high-rate charging process, and timely discharge the gas generated by the electrolyte to the outside of the pole piece.

In order to achieve the purpose, the invention provides a lithium ion battery pole piece, which mainly solves the problem that gas generated in a pole core can be discharged in time.

Preferably, the air discharge duct includes first air discharge duct and second air discharge duct, the air inlet in first air discharge duct is connected one side of pole piece, the gas outlet in first air discharge duct is connected one side of recess, the air inlet in second air discharge duct is connected to the opposite side of recess, the gas outlet in second air discharge duct is connected the opposite side of pole piece.

Preferably, the air discharge duct includes first air discharge duct, second air discharge duct and third air discharge duct, the air inlet in first air discharge duct is connected one side of pole piece, one side of first recess is connected to the gas outlet in first air discharge duct, the opposite side of first recess is connected the air inlet in second air discharge duct, one side of second recess is connected to the gas outlet in second air discharge duct, the air inlet in third air discharge duct is connected to the opposite side of second recess, the gas outlet in third air discharge duct is connected the opposite side of pole piece

Preferably, the groove may be plural, and the plural grooves is at least one.

Preferably, the thickness of the lithium ion battery pole piece is preset to be L1, the depth of the groove is L2, and the value range of L2 is as follows: 1/100L1 < L2 < 1/10L 1.

Preferably, the width of the groove is L3, and the value range of L3 is: coating width × 1/10 < L3 < coating width × 1/3.

Preferably, the number of the exhaust grooves is multiple, and the exhaust grooves are arranged in a staggered manner.

Preferably, the exhaust groove and the groove form an included angle of 0-180 °.

Preferably, the depth of the exhaust channel is L8, and the value range of L8 is: 1/10L2 < L8 < 1/2L 2.

Preferably, the width of the exhaust passage is L9, and the value range of L9 is: l9 is more than 5mm and less than 200 mm.

The application also provides a lithium ion battery, which comprises any one of the lithium ion battery pole pieces.

The pole piece comprises the mass flow body and the coating of coating on the mass flow body, the purpose of the recess design of increase lies in guaranteeing that it can reach the function of local stock solution in big multiplying power circulation process, be unlikely to electrolyte and crowd outside the pole piece, guarantee that can abundant supplementary electrolyte in circulation process positive and negative pole piece space, it has the air discharge duct to increase the design between the recess, can ensure that the gas that produces can in time discharge in the pole piece, can not bring the difference at interface because gaseous deposit in inside on the one hand, on the other hand can ensure that the electrolyte of storing in the recess does not dissociate to the pole piece outside through the air discharge duct, the both sides of pole piece and the both sides of recess are connected to two at least air discharge ducts, so that the gas that produces can be discharged from the air discharge duct of the two of connecting the pole piece both sides, form an exhaust passage.

Drawings

FIG. 1 is a schematic diagram of a top view of a lithium ion battery pole piece in one embodiment;

FIG. 2 is a schematic diagram of a top view of a lithium ion battery pole piece in another embodiment;

FIG. 3 is a side view of the lithium ion battery pole piece shown in FIG. 1;

FIG. 4 is a groove angle diagram of one embodiment of a lithium ion battery pole piece of the present invention;

FIG. 5 is a depth view of an exhaust groove of an embodiment of a lithium ion battery pole piece of the present invention;

FIG. 6 is an angle view of an exhaust slot of an embodiment of a lithium ion battery pole piece of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative only and should not be construed as limiting the invention.

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments, it is to be understood that the specific embodiments described herein are only for the purpose of explaining the present invention, and are not to be used as limitations of the present invention.

Referring to fig. 1 to 3, the present invention provides a lithium ion battery pole piece, which mainly solves the problem that gas generated in a pole piece core can be discharged in time, wherein the pole piece core comprises a current collector and a coating coated on the current collector, the coating is provided with a groove, the groove is arranged along the length direction of the pole piece, an exhaust groove is arranged along the width direction of the pole piece, the coating is also provided with an exhaust groove forming a predetermined included angle with the groove, and the exhaust groove is used for communicating the groove with the outside of the pole piece.

In specific implementation, one groove can be arranged on the coating according to needs, and a plurality of grooves can also be arranged on the coating according to needs. Correspondingly, the number and the position of the exhaust grooves on the coating can be adjusted adaptively according to needs.

For example, as shown in FIG. 1, in one embodiment, the coating is provided with a groove. Correspondingly, the exhaust groove 2 comprises a first exhaust groove 5 and a second exhaust groove 6, an air inlet of the first exhaust groove 5 is connected with one side of the pole piece, an air outlet of the first exhaust groove 5 is connected with one side of the groove 3, the other side of the groove 3 is connected with an air inlet of the second exhaust groove 6, and an air outlet of the second exhaust groove 6 is connected with the other side of the pole piece; the gas is discharged from the gas inlet of the first gas discharge groove 5 and the gas outlet of the second gas discharge groove 6.

The pole piece is formed by a current collector and a coating coated on the current collector, and the coating can be attached to the surface of the current collector in a roller rolling mode. In the process of compacting the coating by the roller, the roller is provided with a bulge, the thickness of the bulge does not exceed the thickness of the coating, the coating can be deeply rolled in the rolling process to form a groove 3, the design of the increased groove aims to ensure that the groove can achieve the function of local liquid storage in the large-multiplying-power circulation process, electrolyte is not extruded out of a pole core, the electrolyte can be fully supplemented in gaps of positive and negative pole pieces in the circulation process, the groove 3 is designed along the length direction of the pole pieces, an exhaust groove is arranged in the width direction of the pole pieces, an exhaust groove 2 is additionally arranged among the grooves 3, through the design of the exhaust groove 2, gas generated in the pole core can be timely exhausted, on one hand, the difference of interfaces caused by the gas stored in the inner part can not be caused, on the other hand, the electrolyte stored in the groove 3 can be ensured not to be dissociated to the outside of the pole core through the exhaust groove 2, the direction of the exhaust grooves 2 and the direction of the pole piece cannot be arranged in parallel, and the purpose is to exhaust gas generated by electrolyte in the grooves 3 to the outside of the pole piece, so that the exhaust grooves are arranged in different directions, and at least two exhaust grooves 2 are connected with two sides of the pole piece and two sides of the grooves 3, so that the generated gas can be exhausted from the exhaust grooves 2 which are connected with the two sides of the pole piece to form an exhaust channel.

In another embodiment, shown in fig. 2, the coating is provided with a plurality of grooves 3. Correspondingly, exhaust duct 2 includes first exhaust duct 5, second exhaust duct 6 and third exhaust duct 7, 5 air inlets in first exhaust duct are connected one side of pole piece, one side of first recess 3 is connected to the gas outlet in first exhaust duct 5, the opposite side of first recess 3 is connected the air inlet of third exhaust duct 7, one side of second recess 3 is connected to the gas outlet in third exhaust duct 7, the air inlet of second exhaust duct 6 is connected to the opposite side of second recess 3, the gas outlet of second exhaust duct 6 is connected the opposite side of pole piece.

In this embodiment, in the case that there are a plurality of grooves 3, the exhaust grooves 2 are disposed between each groove 3 and at two ends of the pole piece 1, so as to form an exhaust channel, and exhaust the gas existing in the most central groove, and the plurality of exhaust grooves 2 may be disposed in a straight line, and the plurality of exhaust grooves 2 in a straight line may cause exhaust, and simultaneously, may also exhaust a certain amount of electrolyte, which is not favorable for the grooves to store electrolyte, and a more preferable embodiment is that, without being disposed in a straight line, the pressure required for exhausting the gas is less than the pressure required for exhausting the liquid, so that the gas may be exhausted more easily than the liquid under a certain pressure, and similarly, the exhaust grooves 2 disposed in a staggered manner also avoid the amount of electrolyte exhausted by the exhaust grooves 2 disposed in a straight line.

In one embodiment, the number of the grooves 3 may be at least one.

As shown in fig. 3, it is concrete, recess 3 is one or more, the setting of recess 3 can be for using the mass flow body to set up as the axial symmetry, also can be asymmetric crisscross setting, only need in the in-process of roll coating with the position of recess 3 set up can, simultaneously because the difference of the position setting of recess 3, the interval that forms between the recess 3 also can be different, through increasing the recess design for the pole piece, can alleviate in big multiplying power circulation process, inside electrolyte along with the increase of number of cycles is ceaselessly crowded utmost point core, and lead to the material to be in the starved state and arouse local polarization too big, form the phenomenon of lithium analysis.

In an embodiment, the groove 3 is a quadrangle extending along the concave direction of the groove 3, an included angle formed between a side edge of the groove 3 and a bottom edge of the groove 3 is an inner angle, an included angle formed between a side edge of the groove 3 and the coating is an outer angle, and the inner angle and the outer angle are staggered angles.

As shown in fig. 4, specifically, the groove 3 is a quadrilateral, such as a square groove, a long groove, a trapezoid groove, etc., and the inner angle and the outer angle are staggered angles，R₁，R₂，R₃，R₄Value is, R₁=R₂=R₃=R₄Or R₁=R₂≠R₃=R₄。

The shape of the rolled groove 3 may also be unlimited, and may be a right-angle groove, a semicircular groove, a triangular groove 3, or the like.

In an embodiment, the thickness of the lithium ion battery pole piece is preset to be L₁The depth of the groove 3 is L₂The value range of L2 is: 1/100L₁＜L₂＜1/10L₁The width of the groove is L₃，L₃The value range is as follows: coating width x 1/10 < L₃< coating width x 1/3.

As shown in fig. 3, in particular, the values of the groove size are assumed to be: l is₄，L₅，L₆，L₇The value is related to the width of the coating and is arranged according to the position interval of the groove 3, wherein L₄=L₅=L₆=L₇Or L₄≠L₅≠L₆≠L₇Presetting the thickness of the pole piece coating to be L₁And L is₁Taking values: the depth of the groove is L which is obtained by calculation according to the specific coating amount and the volume density design condition of the pole piece₂，L₂The value range is as follows: 1/100L₁＜L₂＜1/10L₁I.e. the depth of the grooves 3 must not exceed the thickness of the pole piece coating.

In one embodiment, an included angle between the exhaust groove 2 and the groove 3 is a predetermined angle, and the depth of the exhaust channel is L₈，L₈The value range is as follows: 1/10L₂＜L₈＜1/2L₂The width of the exhaust passage is L₉，L₉ The value range is as follows: l is more than 5mm₉＜200mm。

As shown in fig. 5, specifically, the included angle formed by the exhaust groove 2 and the groove 3 is any one of 0 ° to 180 °, and does not include 0 ° and 180 °, and the position of the exhaust channel does not make special requirements for each half of the wound batteryThe circle needs at least a set of exhaust passage can communicate the middle groove with the pole core outside can, exhaust passage's degree of depth is L8, and the value range of L8 is: 1/10L₂＜L₈＜1/2L₂The width of the exhaust channel is L9, and the value range of L9 is as follows: l is more than 5mm₉＜200mm。

In one embodiment: and (4) verifying the model: c15-270Ah cell, dressing width: and (3) positive electrode: 330.0mm, negative electrode: 338.0mm, L₁: 142 um; designing the size of the groove: l is₂=8um，L₄=L₅=80mm，L₃=20um，R₁=R₂=R₃=R₄=105 °; designing an exhaust passage: l is₈=2um，L₉=50mm，R₅=60°，R₆=R₇=R₈=R₉=105 °, 2 sets of exhaust channels per half winding turn;

comparative example: only the groove 3 is designed, the groove 3 is dimensioned: l is₂=8um，L₄=L₅=80mm，L₃=20um，R₁=R₂=R₃=R₄=105 °; the battery with the two design schemes respectively carries out overcharge safety test (tightening before test) to verify the internal exhaust effect of the battery core, and the opening time of the battery core with the groove and the exhaust channel is 2 mm earlier than that of the battery core with the groove and the exhaust channel in comparison with the battery core with the groove and the exhaust channel in comparison, the battery core with the groove and the exhaust channel is released in advance, so that the safety risk is reduced. Therefore, the exhaust channel is increased, and gas can be released from the pole core more smoothly

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.