CN212303754U

CN212303754U - Winding type lithium ion battery cell

Info

Publication number: CN212303754U
Application number: CN202021212117.3U
Authority: CN
Inventors: 汪圣龙; 蒋中林
Original assignee: Dongguan Mofang New Energy Technology Co ltd
Current assignee: Dongguan Mofang New Energy Technology Co ltd
Priority date: 2020-06-28
Filing date: 2020-06-28
Publication date: 2021-01-05
Anticipated expiration: 2030-06-28

Abstract

The utility model belongs to the technical field of lithium ion batteries, in particular to a winding type lithium ion cell, which comprises pole pieces and a diaphragm arranged between the pole pieces, wherein each pole piece comprises an active substance layer coating area and a first inorganic coating area arranged on the edge of the periphery of the pole piece, the surface of the active substance layer coating area is coated with an active substance layer, and the surface of the first inorganic coating area is coated with a first inorganic coating; the diaphragm comprises a pole piece corresponding area and a diaphragm coating area adjacent to the pole piece corresponding area, the pole piece corresponding area and the pole piece are arranged correspondingly, and the surface of the diaphragm coating area is coated with a second inorganic coating. The utility model discloses cut along first inorganic coating when cutting, can eliminate the influence of pole piece edge burr, reduce the short circuit rate of battery and improve the battery security. The utility model discloses can also avoid the burr on pole piece surface to pierce through the diaphragm, can also prevent that the diaphragm from causing positive negative pole contact short circuit when the shrink, further improve the security performance of battery.

Description

Winding type lithium ion battery cell

Technical Field

The utility model belongs to the technical field of lithium ion battery, especially, relate to a coiling type lithium ion cell.

Background

Lithium ion batteries have the advantages of light weight, good safety performance and the like, so that the lithium ion batteries are applied to the fields of mobile electronic equipment such as Bluetooth headsets, mobile phones, notebook computers, tablet computers and cameras, portable mobile power supplies and the like. Meanwhile, lithium ion batteries have also been applied in the fields of electric motorcycles, electric automobiles, and the like in batches.

In the prior art, the pole piece is generally coated with the active substance layer intermittently, the intermittent coating can reserve a part of current collector edge empty foil areas on two sides of the active substance layer without coating, and the current collector edge empty foil areas can be cut off in the subsequent cutting process. However, when the foil area of the edge of the current collector is cut, due to the characteristics of the material of the positive electrode active material layer, a relatively large burr is generated at the cut position, and if the burr is not processed, the burr pierces the separator, so that the internal short circuit of the battery cell is caused.

At present, the diaphragm is mainly a porous medium composed of polyolefins such as polyethylene, polypropylene and the like, the polyolefin diaphragm has a melting point of 200 ℃ or lower, and when the temperature of the battery rises due to internal or external factors, the diaphragm is easy to shrink so that the positive electrode and the negative electrode are short-circuited, and thermal runaway of the battery and even fire accidents occur.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a: aiming at the defects of the prior art, the winding type lithium ion battery cell is provided, the probability of short circuit of the battery can be reduced, and meanwhile, the safety performance of the battery cell can be improved.

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

a wound lithium ion battery cell comprises pole pieces and a diaphragm arranged between the pole pieces, wherein the pole pieces comprise an active substance layer coating area and a first inorganic coating area arranged on the periphery of the pole pieces, the surface of the active substance layer coating area is coated with an active substance layer, and the surface of the first inorganic coating area is coated with a first inorganic coating; the diaphragm comprises a pole piece corresponding area and a diaphragm coating area adjacent to the pole piece corresponding area, the pole piece corresponding area and the pole piece are arranged correspondingly, and the surface of the diaphragm coating area is coated with a second inorganic coating.

The utility model discloses an among the coiling type lithium ion cell, because the diaphragm can be heated the shrink and lead to positive negative pole contact short circuit, the width of diaphragm needs to be greater than the width of pole piece, and the pole piece generally sets up in the positive centre of diaphragm. In order to avoid the burr at the edge of the pole piece to puncture the diaphragm, the utility model discloses at the first inorganic coating of surface coating at the edge all around of pole piece. Additionally, the utility model discloses in, the width that the pole piece of diaphragm corresponds the district need be less than the width of pole piece, just so can make the marginal pressfitting of pole piece on the surface in the diaphragm coating district of diaphragm, at the inorganic coating of diaphragm coating district coating second of diaphragm, just so can prevent that the burr at pole piece edge from punctureing the short circuit that the diaphragm caused.

As an improvement of coiling type lithium ion cell, the length of diaphragm is greater than the length of pole piece, the width of diaphragm is greater than the width of pole piece. The width of the positive pole piece, the width of the negative pole piece and the width of the diaphragm are sequentially increased, the diaphragm is required to separate the positive pole from the negative pole during winding, short circuit is prevented, and the negative pole piece is slightly wider than the positive pole piece, so that the electrical property of the positive pole material can be fully exerted.

As an improvement of the wound lithium ion battery cell of the present invention, the active material layer is a positive electrode active material layer or a negative electrode active material layer.

As an improvement of coiling formula lithium ion cell, the length in diaphragm coating district with the length or the width of diaphragm are the same, the width in diaphragm coating district is 2 ~ 10 mm.

As an improvement of coiling formula lithium ion cell, the length in first inorganic coating district with the length or the width of pole piece are the same, the width in first inorganic coating district is 2 ~ 10 mm.

As an improvement of coiling formula lithium ion cell, first inorganic coating includes ceramic particle and binder, the second inorganic coating includes ceramic particle and binder, and ceramic particle includes at least one in boehmite, calcium oxide, zinc oxide, magnesium oxide, titanium dioxide, silica, zirconium dioxide, tin dioxide, ceric oxide, aluminium oxide, calcium carbonate and the barium titanate, but first inorganic coating and second inorganic coating the same setting, also the setting of difference.

As an improvement of coiled lithium ion battery cell, still including setting up the third coating on pole piece corresponding region surface. The third coating coated on the surface of the corresponding area of the pole piece of the diaphragm is a porous insulating layer consisting of inorganic particles, and the porous insulating layer can prevent the positive electrode and the negative electrode from directly contacting when the diaphragm contracts or is damaged, so that the fire problem is avoided.

As an improvement of the coiled lithium ion battery cell of the present invention, the coiled lithium ion battery cell further comprises a fourth coating layer disposed on the surface of the active material layer. The fourth coating coated on the surface of the active material layer is an organic coating, and organic particles in the organic coating can be swelled in electrolyte, so that the organic coating has good electrolyte absorption capacity, the ion conductivity of the layer is improved, and the lithium ion battery has better cycle performance.

Compared with the prior art, the beneficial effects of the utility model include but are not limited to:

the utility model provides a coiled lithium ion battery cell, including the pole piece and setting up the diaphragm between the pole piece, the pole piece includes active substance layer coating area and sets up in the first inorganic coating area of pole piece edge all around, the surface coating in active substance layer coating area has the active substance layer, the surface coating in first inorganic coating area has first inorganic coating; the diaphragm comprises a pole piece corresponding area and a diaphragm coating area adjacent to the pole piece corresponding area, the pole piece corresponding area and the pole piece are arranged correspondingly, and the surface of the diaphragm coating area is coated with a second inorganic coating.

The utility model discloses at the first inorganic coating of pole piece edge coating all around, cut along first inorganic coating when cutting, can eliminate the influence of pole piece edge burr, reduce the short circuit rate of battery and improve the security performance of battery.

The utility model discloses the diaphragm coating district coating at the diaphragm has the inorganic coating of second, also can avoid the burr at pole piece edge to puncture the diaphragm, can also prevent simultaneously that the diaphragm from causing positive negative pole contact short circuit when the shrink, has further improved the security performance of battery.

Drawings

Fig. 1 is a schematic structural diagram of a pole piece in example 1.

Fig. 2 is a cross-sectional view of the pole piece of example 1.

Fig. 3 is a schematic structural view of the separator in example 1.

Fig. 4 is a sectional view of the separator in example 1.

Fig. 5 is a sectional view of the separator in example 2.

Figure 6 is a cross-sectional view of the pole piece of example 3.

In the figure: 1-pole piece, 11-active substance layer coating area, 12-first inorganic coating area, 2-diaphragm, 21-pole piece corresponding area, 22-diaphragm coating area, 3-active substance layer, 4-first inorganic coating, 5-second inorganic coating, 6-third coating, and 7-fourth coating.

Detailed Description

In order to make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments and drawings of the specification, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

As used in this specification and the appended claims, certain terms are used to refer to particular components, and it will be appreciated by those skilled in the art that a manufacturer may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", horizontal "and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, detachable connections, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Example 1

As shown in fig. 1 to 4, a wound lithium ion battery cell includes pole pieces 1 and a separator 2 disposed between the pole pieces 1, where the pole piece 1 includes an active material layer coating area 11 and a first inorganic coating area 12 disposed on the periphery of the pole piece 1, the surface of the active material layer coating area 11 is coated with an active material layer 3, and the surface of the first inorganic coating area 12 is coated with a first inorganic coating 4; the diaphragm 2 comprises a pole piece corresponding area 21 and a diaphragm coating area 22 adjacent to the pole piece corresponding area 21, the pole piece corresponding area 21 is arranged corresponding to the pole piece 1, and the surface of the diaphragm coating area 22 is coated with the second inorganic coating 5.

Further, the length of the diaphragm 2 is greater than that of the pole piece 1, and the width of the diaphragm 2 is greater than that of the pole piece 1.

Further, the active material layer 3 is a positive electrode active material layer or a negative electrode active material layer.

Further, the length of the separator coating region 22 is the same as the length or width of the separator 2, and the width of the separator coating region 22 is 2 to 10 mm.

Further, the length of the first inorganic coating area 12 is the same as the length or width of the pole piece 1, and the width of the first inorganic coating area 12 is 2-10 mm.

Further, the first inorganic coating layer comprises ceramic particles and a binder, the second inorganic coating layer comprises ceramic particles and a binder, the ceramic particles comprise at least one of boehmite, calcium oxide, zinc oxide, magnesium oxide, titanium dioxide, silicon dioxide, zirconium dioxide, tin dioxide, cerium dioxide, aluminum oxide, calcium carbonate and barium titanate, and the first inorganic coating layer and the second inorganic coating layer can be arranged in the same way or in different ways.

Example 2

As shown in fig. 5, this embodiment provides a wound lithium ion battery cell, which, unlike embodiment 1,

and a third coating 6 arranged on the surface of the corresponding area 21 of the pole piece. The third coating 6 is a porous insulating layer composed of inorganic particles, and the porous insulating layer can prevent the positive electrode and the negative electrode from directly contacting when the diaphragm 2 contracts or is damaged, so that the fire problem is avoided.

The rest is the same as embodiment 1, and the description is omitted here.

Example 3

As shown in fig. 6, the present embodiment provides a wound lithium ion battery cell, which, unlike embodiment 1,

and a fourth coating layer 7 provided on the surface of the active material layer 3. The fourth coating 7 is an organic coating. The organic particles in the organic coating can swell in the electrolyte, so that the organic coating has good electrolyte absorption capacity, the ion conductivity of the layer is improved, and the lithium ion battery has better cycle performance.

The rest is the same as embodiment 1, and the description is omitted here.

Example 4

This example provides a wound lithium ion battery cell, which, unlike example 1,

and a third coating 6 arranged on the surface of the corresponding area 21 of the pole piece. The third coating layer 6 is a porous insulating layer composed of inorganic particles.

And a fourth coating layer 7 provided on the surface of the active material layer 3. The fourth coating 7 is an organic coating.

The rest is the same as embodiment 1, and the description is omitted here.

Variations and modifications to the above-described embodiments may become apparent to those skilled in the art from the disclosure and teachings of the above description. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious modifications, replacements or variations made by those skilled in the art on the basis of the present invention belong to the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A coiled lithium ion battery cell is characterized by comprising pole pieces and a diaphragm arranged between the pole pieces, wherein the pole pieces comprise active material layer coating areas and first inorganic coating areas arranged on the peripheral edges of the pole pieces, the surfaces of the active material layer coating areas are coated with active material layers, and the surfaces of the first inorganic coating areas are coated with first inorganic coatings; the diaphragm comprises a pole piece corresponding area and a diaphragm coating area adjacent to the pole piece corresponding area, the pole piece corresponding area and the pole piece are arranged correspondingly, and the surface of the diaphragm coating area is coated with a second inorganic coating.

2. The wound lithium ion battery cell of claim 1, wherein the length of the separator is greater than the length of the pole piece, and the width of the separator is greater than the width of the pole piece.

3. The wound lithium ion battery cell according to claim 1, wherein the active material layer is a positive electrode active material layer or a negative electrode active material layer.

4. The wound lithium ion battery cell of claim 1, wherein the length of the separator coating zone is the same as the length or width of the separator.

5. The wound lithium ion battery cell of claim 1, wherein the length of the first inorganic coating coated region is the same as the length or width of the pole piece.

6. The wound lithium ion battery cell of claim 1, further comprising a third coating disposed on a surface of the corresponding region of the pole piece.

7. The wound lithium ion battery cell of claim 1, further comprising a fourth coating disposed on a surface of the active material layer.