CN216015425U

CN216015425U - Pole piece, battery core and secondary battery

Info

Publication number: CN216015425U
Application number: CN202122371335.2U
Authority: CN
Inventors: 王涛; 门艳茹; 王阳
Original assignee: Beijing Sankuai Online Technology Co Ltd
Current assignee: Beijing Sankuai Online Technology Co Ltd
Priority date: 2021-09-28
Filing date: 2021-09-28
Publication date: 2022-03-11
Anticipated expiration: 2031-09-28

Abstract

The utility model relates to a pole piece, electric core and secondary battery, the pole piece include the mass flow body (1) and cover in the overburden on mass flow body (1) surface, this overburden is including respectively exposed functional structure layer (2) and active material coating (3), functional structure layer (2) are including adsorbent (21) that are used for at least adsorbing moisture. Through the technical scheme, the pole piece provided by the disclosure can improve the safety reliability and the performance reliability of the battery cell.

Description

Pole piece, battery core and secondary battery

Technical Field

The disclosure relates to the technical field of batteries, in particular to a pole piece, a battery core and a secondary battery.

Background

The secondary battery is a battery that can be continuously used by activating an active material in a charging manner after the battery is discharged, and is widely used in the fields of mobile phones, electric tools, medical electronics, new energy vehicles, energy storage base stations, and the like.

A lithium ion battery is a secondary battery that mainly relies on the intercalation and deintercalation of lithium ions between positive and negative active materials to complete the charging and discharging processes. In the using process of the lithium ion battery, moisture can continuously slowly permeate into the battery cell from the external environment, then water reacts with lithium salt to generate Hydrogen Fluoride (HF), the hydrogen fluoride destroys an anode SEI (Solid Electrolyte Interface) to generate gases such as carbon dioxide, and along with the increase of gas amount, the internal pressure of the battery cell is increased, so that the packaging reliability of the battery cell is poor, safety accidents are easily caused, and the safe use of the lithium ion battery is influenced. In addition, the gas production process destroys an interface film (SEI film) of a cathode and an anode, accelerates irreversible transformation of materials, and simultaneously leads to deterioration of a cathode/diaphragm/anode interface due to gas generation, so that internal impedance of the battery is increased, attenuation is accelerated, and the cycle life of the lithium ion battery is influenced.

SUMMERY OF THE UTILITY MODEL

The purpose of this disclosure is to provide a pole piece, electric core and secondary battery to can promote the fail-safe nature and the dependability of the battery.

In order to achieve the above object, according to a first aspect of the present disclosure, there is provided a pole piece, including a current collector and a cover layer covering a surface of the current collector, the cover layer including a functional structure layer and an active material coating layer respectively exposed to the outside, the functional structure layer including an adsorbent for adsorbing at least moisture.

Optionally, the adsorbent is an adsorbent capable of adsorbing moisture and carbon dioxide gas.

Optionally, the adsorbent is made of calcium hydroxide or calcium oxide.

Optionally, the adsorbent is in the form of powder particles, the current collector is provided with a plurality of accommodating grooves, and the accommodating grooves are used for accommodating the adsorbent.

Alternatively, the plurality of receiving grooves may be irregularly distributed and formed on the surface of the current collector through an etching process.

Optionally, the functional structure layer includes a fixed film, the fixed film has a plurality of micropores, the adsorbent is located between the fixed film and the current collector, and the fixed film covers the adsorbent.

Optionally, the fixed membrane is a polyacrylonitrile fiber membrane.

Optionally, the cover layer is composed of the functional structure layer and the active material coating, and the functional structure layer and the active material coating are arranged on two opposite sides of the current collector in the width direction side by side.

According to a second aspect of the present disclosure, an electrical core is provided, which includes a positive plate, a negative plate, an electrolyte, and a separation film located between the positive plate and the negative plate, where the positive plate and/or the negative plate is the above-mentioned pole piece.

According to a third aspect of the present disclosure, there is provided a secondary battery comprising a case and the above-described battery cell, the battery cell being enclosed in the case.

Through above-mentioned technical scheme, this openly provides a pole piece has the overburden at the surface of mass flow body, and this overburden includes functional structure layer and active material coating, and functional structure layer and active material coating all expose in the surface of mass flow body, and wherein, functional structure layer is including being used for at least adsorbing the adsorbent of moisture. In the use process of the battery core, moisture can continuously slowly permeate from the external environment to the inside of the battery core, the moisture can be adsorbed by the adsorbing body, gas generated by water electrolysis is avoided, the pressure inside the battery core is increased, the packaging reliability of the battery core is further ensured, safety accidents are prevented, the safety and reliability of the battery are improved, the internal impedance of the battery can be effectively prevented from being increased by damaging a cathode and anode interface film in the gas production process, the attenuation is slowed down, and the cycle life of the battery and the performance reliability of the battery are further improved.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

fig. 1 is a schematic cross-sectional structural diagram of a pole piece provided in an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a pole piece provided in an embodiment of the present disclosure;

fig. 3 is a schematic cross-sectional structural diagram of a functional structure layer in a pole piece provided in an embodiment of the present disclosure.

Description of the reference numerals

1-current collector; 11-a holding tank; 2-functional structural layer; 21-an adsorbent; 22-a fixed membrane; 3-active substance coating.

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

In the present disclosure, the use of directional terms such as "inner and outer" means "inner and outer" with respect to the corresponding profile of the component itself, unless otherwise specified. In the following description, when referring to the figures, the same reference numbers in different figures denote the same or similar elements, unless otherwise explained. The foregoing definitions are provided to illustrate and describe the present disclosure only and should not be construed to limit the present disclosure.

According to a specific embodiment of the first aspect of the present disclosure, referring to fig. 1 to 3, a pole piece is provided, where the pole piece includes a current collector 1 and a cover layer covering the surface of the current collector 1, the cover layer includes a functional structure layer 2 and an active material coating layer 3 respectively exposed, and the functional structure layer 2 includes an adsorbent 21 for adsorbing at least moisture.

Through the technical scheme, the pole piece provided by the disclosure is covered with the covering layer on the surface of the current collector 1, the covering layer comprises the functional structure layer 2 and the active substance coating 3, the functional structure layer 2 and the active substance coating 3 are both exposed on the surface of the current collector 1, and the functional structure layer 2 comprises the adsorption body 21 for at least adsorbing moisture. During the use of the battery core, moisture can continuously slowly permeate from the external environment to the inside of the battery core, and the moisture can be adsorbed by the adsorbing body 21, so that the phenomenon that gas is generated by water electrolysis to increase the pressure inside the battery core is avoided, the packaging reliability of the battery core is further ensured, the occurrence of safety accidents is prevented, the safety and reliability of the battery are improved, the internal impedance of the battery is effectively prevented from being increased by damaging a cathode and anode interface film in the gas production process, the attenuation is slowed down, and the cycle life of the battery and the performance reliability of the battery are further improved.

In the use process of the battery, because moisture in the external environment can continuously and slowly permeate into the battery, in the charging process of the battery, hydrogen and oxygen can be generated by water electrolysis, the pressure inside the battery is increased, the safe use of the battery is further influenced, the electrolyte can react with water until all electrolyte substances are reacted, and the recycling performance of the battery is influenced, so that the water can be prevented from being electrolyzed to generate the hydrogen and the oxygen by adsorbing the moisture by an adsorbate, the possibility of generating gas in the use process of the battery is reduced, and the safe use and the recycling performance of the battery can be ensured to a great extent. It should be noted that the electrode sheet provided by the present disclosure may be used in various secondary batteries, such as nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid (or lead-storage) batteries, lithium ion batteries, polymer lithium ion batteries, and the like, and the present disclosure is not limited thereto.

In a lithium ion battery, an electrolyte solution is generally prepared from a high-purity organic solvent, an electrolyte lithium salt (e.g., lithium perchlorate, lithium hexafluorophosphate, lithium tetrafluoroborate, etc.), a necessary additive, and the like, in a certain ratio under a certain condition. In the case where hydrogen fluoride is generated by water and lithium hexafluorophosphate in the Electrolyte lithium salt, and gas such as carbon dioxide is generated by hydrogen fluoride destroying the anode SEI (Solid Electrolyte Interface), the adsorbent 21 may be an adsorbent 21 capable of adsorbing moisture and carbon dioxide gas. In one embodiment, the adsorbent 21 may be composed of two substances, one for adsorbing moisture and the other for adsorbing carbon dioxide gas. In other embodiments, the adsorbent 21 may be made of calcium hydroxide or calcium oxide, and the calcium hydroxide or calcium oxide can absorb moisture and carbon dioxide gas, so as to further improve the safety reliability and performance reliability of the battery while insulating and protecting.

In the specific embodiments provided in the present disclosure, the absorbent 21 may be coated on the current collector 1 in any suitable manner, for example, by spraying, rolling, or the like. In the embodiment shown in fig. 3, the adsorbent 21 is in the form of powder particles, and in order to facilitate the coating of the adsorbent 21 on the current collector 1, the current collector 1 may be provided with a plurality of receiving grooves 11, and the receiving grooves 11 are used for receiving the adsorbent 21 to improve the adhesion of the adsorbent 21 on the current collector 1.

Wherein, a plurality of holding grooves 11 can be distributed irregularly on the surface of mass flow body 1 through corrosion technology (for example, electroplating, etching, etc.), through this kind of mode, can be convenient for the formation of holding groove 11, and then reduce the production degree of difficulty of mass flow body 1. In other embodiments, the receiving groove 11 may also be regularly formed on the surface of the current collector 1 by machining, in which case the receiving groove 11 may extend in the width direction of the current collector 1 and be arranged in plurality at intervals in the length direction of the current collector 1, or the receiving groove 11 may extend in the length direction of the current collector 1 and be arranged in plurality at intervals in the width direction of the current collector 1, which is not particularly limited by the present disclosure.

In the specific embodiment provided by the present disclosure, the functional structure layer 2 may further include a fixing film 22, the fixing film 22 has a plurality of micropores, the adsorbent 21 is located between the fixing film 22 and the current collector 1, and the fixing film 22 covers the adsorbent 21 for reliably covering the adsorbent 21 on the current collector 1. Here, since the fixed film 22 has a plurality of micropores, moisture and gas can permeate therethrough, so that the moisture and gas can be adsorbed by the adsorbent 21 after permeating through the fixed film 22. It should be noted here that in the case where the adsorbent 21 is coated on the surface of the current collector 1, the fixing film 22 is not necessary, and the surface of the adsorbent 21 may be selectively coated with the fixing film 22, and in the case where the adsorbent 21 is not coated with the fixing film 22, the adsorbent 21 can be reliably coated on the current collector 1.

In one embodiment, the fixed film 22 may be a polyacrylonitrile fiber film coated on the absorbent 21 by an electrospinning method. In other embodiments, the fixing film 22 may also be any fixing film 22 that is stable in properties and has water and air permeable properties, which are not particularly limited by the present disclosure.

In the specific embodiment provided by the present disclosure, referring to fig. 2, the cover layer is composed of a functional structure layer 2 and an active material coating layer 3, and the functional structure layer 2 and the active material coating layer 3 are arranged side by side on opposite sides of the current collector 1 in the width direction.

According to a specific embodiment of the second aspect of the present disclosure, there is provided a battery cell, which includes a positive plate, a negative plate, an electrolyte, and a separation film located between the positive plate and the negative plate, where the positive plate and/or the negative plate is the above-mentioned plate. The electric core that this disclosure provided has above-mentioned characteristics equally, avoids repetition, does not describe herein again.

According to a specific embodiment of a third aspect of the present disclosure, a secondary battery is provided, which includes a casing and the above battery cell, wherein the battery cell is packaged in the casing. The secondary battery provided by the present disclosure also has the above-mentioned features, and is not described herein again in order to avoid redundancy.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. The utility model provides a pole piece, its characterized in that, the pole piece includes current collector (1) and covers in the overburden on current collector (1) surface, this overburden includes functional structure layer (2) and active material coating (3) that expose respectively, functional structure layer (2) are including being used for adsorbing absorbent (21) of moisture at least.

2. The pole piece according to claim 1, characterized in that the adsorbent (21) is an adsorbent capable of adsorbing moisture and carbon dioxide gas.

3. The pole piece of claim 2, characterized in that the adsorbent (21) is made of calcium hydroxide or calcium oxide.

4. The pole piece according to any of the claims 1 to 3, characterized in that the adsorbent (21) is in the form of powder granules, the current collector (1) being provided with a plurality of housing grooves (11), the housing grooves (11) being intended to house the adsorbent (21).

5. The pole piece according to claim 4, characterized in that a plurality of said accommodation grooves (11) are irregularly distributed and formed on the surface of the current collector (1) by an etching process.

6. The pole piece according to any one of claims 1 to 3, characterized in that the functional structure layer (2) comprises a fixing film (22), the fixing film (22) has a plurality of micropores, the absorbent (21) is located between the fixing film (22) and the current collector (1), and the fixing film (22) covers the absorbent (21).

7. The pole piece according to claim 6, characterized in that the fixing film (22) is a polyacrylonitrile fiber film.

8. The pole piece according to claim 1, characterized in that the cover layer is composed of the functional structure layer (2) and the active material coating (3), the functional structure layer (2) and the active material coating (3) being arranged side by side on opposite sides of the current collector (1) in the width direction.

9. An electrical core comprising a positive plate, a negative plate, an electrolyte and a separator between the positive plate and the negative plate, wherein the positive plate and/or the negative plate is a plate according to any one of claims 1 to 8.

10. A secondary battery comprising a casing, wherein the secondary battery further comprises the cell of claim 9 enclosed in the casing.