CN215008283U - Battery cell structure, lithium ion battery and electronic equipment - Google Patents

Battery cell structure, lithium ion battery and electronic equipment Download PDF

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CN215008283U
CN215008283U CN202120411121.0U CN202120411121U CN215008283U CN 215008283 U CN215008283 U CN 215008283U CN 202120411121 U CN202120411121 U CN 202120411121U CN 215008283 U CN215008283 U CN 215008283U
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pole piece
cell structure
coating area
winding
battery
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蒋合林
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Beijing Xiaomi Mobile Software Co Ltd
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Beijing Xiaomi Mobile Software Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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Abstract

The disclosure relates to the technical field of lithium batteries, and particularly provides a battery cell structure, a lithium ion battery and electronic equipment. Cell structure, include: the battery cell structure comprises a first pole piece and a second pole piece, wherein the first pole piece and the second pole piece are stacked and wound to form the battery cell structure; the current collector at the winding tail end of the first pole piece is provided with a single-surface coating area, and the coating direction of the single-surface coating area faces the inner side of the winding direction; the winding tail end of the second pole piece is provided with a blank coating area, and the blank coating area is coated on the winding outer side of the single-surface coating area. The cell structure of the present disclosure improves battery energy density.

Description

Battery cell structure, lithium ion battery and electronic equipment
Technical Field
The disclosure relates to the technical field of lithium batteries, in particular to a battery cell structure, a lithium ion battery and electronic equipment.
Background
The lithium ion battery is used as an energy storage device capable of being charged and discharged circularly, and is widely applied to the fields of electronic products, new energy automobiles and the like at present. When subjected to external force such as impact, nail penetration and the like which seriously damage the battery structure, the lithium ion battery is easy to combust and explode.
In the related art, a vest structure is often used to improve the reliability of the lithium ion battery, that is, a safe short circuit region is formed by covering a blank region of the outermost ring of the positive and negative current collectors. The vest structure causes a reduction in the energy density of the battery.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem that the energy density of a battery is reduced by a waistcoat structure, the embodiment of the disclosure provides a battery cell structure, a lithium ion battery and electronic equipment.
In a first aspect, an embodiment of the present disclosure provides a cell structure, including:
the battery cell structure comprises a first pole piece and a second pole piece, wherein the first pole piece and the second pole piece are stacked and wound to form the battery cell structure;
the current collector at the winding tail end of the first pole piece is provided with a single-surface coating area, and the coating direction of the single-surface coating area faces the inner side of the winding direction; the winding tail end of the second pole piece is provided with a blank coating area, and the blank coating area is coated on the winding outer side of the single-surface coating area.
In some embodiments, the length of the blank coated area is not less than the length of the single coated area.
In some embodiments, the length of the blank coated area is at least half a turn of the cell structure winding.
In some embodiments, the length of the blank coating region is one turn of the cell structure.
In some embodiments, the winding head end of the second pole piece is located inside the winding head end of the first pole piece;
the first pole piece sequentially comprises a tab welding area, a double-sided coating area and a single-sided coating area from the head end to the tail end;
the second pole piece sequentially comprises a pole lug welding area, a single-side coating area, a double-side coating area and the blank coating area from the head end to the tail end.
In some embodiments, the tab welding area of the first pole piece and the tab welding area of the second pole piece are stacked to form a first winding of the cell structure, the double-coated area of the first pole piece and the single-coated area of the second pole piece form a second winding of the cell structure, the single-coated area of the first pole piece and the double-coated area of the second pole piece form a third winding of the cell structure, and the blank coated area of the second pole piece is wrapped around the outside of the third winding structure.
In some embodiments, the first pole piece is a positive pole piece and the second pole piece is a negative pole piece.
In some embodiments, the cell structure further includes:
the first tab is welded at the winding head end of the first pole piece; and
and the second tab is welded at the winding head end of the second pole piece.
In a second aspect, an embodiment of the present disclosure provides a lithium ion battery, including the cell structure described in any embodiment of the first aspect.
In a third aspect, the present disclosure provides an electronic device, including the lithium ion battery according to any one of the embodiments of the second aspect.
The battery cell structure comprises a winding type first pole piece and a winding type second pole piece, wherein a current collector at the winding tail end of the first pole piece is provided with a single-surface coating area, the coating direction of the single-surface coating area faces the inner side of the winding direction, the winding tail end of the second pole piece is provided with a blank coating area, and the blank coating area is coated on the winding outer side of the single-surface coating area. The waistcoat structure is formed by the blank coating area of the second pole piece and the side, not coated with the active substance, of the first pole piece, so that the safety of the lithium ion battery when the lithium ion battery is damaged by impact, nail penetration and the like is improved.
Drawings
In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a sectional structure view of a battery cell in the related art.
Fig. 2 is a cross-sectional view of a cell structure according to some embodiments of the present disclosure.
Detailed Description
The technical solutions of the present disclosure will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only some embodiments of the present disclosure, but not all embodiments. All other embodiments, which can be derived by one of ordinary skill in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure. In addition, technical features involved in different embodiments of the present disclosure described below may be combined with each other as long as they do not conflict with each other.
The lithium ion battery consists of a positive plate, a negative plate, a diaphragm and organic electrolyte, and because the electrolyte is an organic inflammable body, when the battery is subjected to external force action of impacting, nailing and the like which seriously damages the battery structure, short circuit occurs between the positive and negative electrodes of the battery instantly, and the short circuit generates a large amount of joule heat to cause the battery to be ignited or even explode.
In the related art, a vest structure is often used to improve the reliability of the lithium ion battery. For example, fig. 1 shows a cross-sectional structure of a wound cell, in which a solid line indicates a positive electrode sheet, a dotted line indicates a negative electrode sheet, and the positive and negative electrode sheets are stacked and wound to form a wound cell structure. For clarity of the display of the cell results, the separator between the positive and negative electrodes is not shown in the drawings, as will be understood by those skilled in the art.
It can be understood that the positive and negative electrode plates refer to the positive and negative current collectors coated with active material, so as to be between the positive and negative electrodesA lithium ion moving path is formed between the two electrodes, and the charging and discharging of the battery are realized. For example, aluminum foil is generally used as the current collector of the positive electrode sheet, and lithium cobaltate LiCoO is generally used as the active material coated on the positive electrode2Lithium manganate LiMn2O4, lithium iron phosphate LiFePO4 and the like; the current collector of the negative plate is generally copper foil, and the active substance coated on the negative plate can be graphite and lithium titanate Li2TiO3And the like. In fig. 1, the thickness of lines is used to indicate the coating area of the active material, including double-sided coating, single-sided coating, and uncoated blank area, and the single-sided coating direction of the active material can be clearly understood based on fig. 1, and the disclosure will not be repeated herein.
With continued reference to fig. 1, at the winding ends of the positive and negative electrode sheets, i.e. the tail portions of the winding structure, the positive and negative electrode sheets include a blank area not coated with active material, and the positive and negative electrode sheets in the blank area form a waistcoat structure 100 of the battery cell. When the battery is damaged by collision, nail penetration and the like, the impedance between the blank pole pieces in the waistcoat structure 100 area is low, a safe short circuit mode can be formed, and the pole pieces are prevented from being combusted and exploded. At the same time, however, it can be seen that the waistcoat structure 100 does not provide energy to the battery because the active material is not coated, resulting in a lower energy density of the battery at the same thickness.
Based on the defects in the related art, the embodiments of the present disclosure provide a cell structure to improve the energy density of a battery.
In some embodiments, the cell structure of the present disclosure includes a first pole piece and a second pole piece, where the first pole piece and the second pole piece are positive and negative pole pieces of the cell, respectively, and the first pole piece and the second pole piece are stacked and wound to form the cell structure, that is, the cell structure is a wound cell.
The current collector at the winding end of the first pole piece is provided with a single-surface coating area, namely one surface of the current collector is coated with active substances, the other surface of the current collector is not coated with the active substances, and the direction of the single-surface coating of the active substances is towards the inner side of the winding direction. The winding tail end of the second pole piece is provided with a blank coating area, namely the tail end of the second pole piece is an area which is not coated with active substances, and the blank coating area of the second pole piece is coated on the winding outer side of the single-surface coating area of the first pole piece. That is, at the winding end of the cell structure, the vest structure is formed by the blank coating area of the second pole piece and the single-side coating area of the first pole piece.
Therefore, the battery core structure of the embodiment of the disclosure forms the vest structure by using the blank coating area of the second pole piece and the single-side coating area of the first pole piece, so as to improve the safety of the battery when the battery is damaged by impact, through-nails and the like. Meanwhile, the active substance is coated on the single surface of the first pole piece of the waistcoat structure, so that energy can be provided for the battery and the energy density of the battery can be improved under the condition of the same battery cell thickness compared with the traditional waistcoat structure.
Fig. 2 shows a cell structure in an embodiment of the present disclosure, and the cell structure in the embodiment of the present disclosure is described below with reference to fig. 2.
As shown in fig. 2, in the present embodiment, the cell structure includes a first pole piece and a second pole piece, where the first pole piece is a positive pole piece 210, and the second pole piece is a negative pole piece 220. The positive electrode sheet 210 and the negative electrode sheet 220 are stacked and wound to form a winding type cell structure, and a separator is arranged between the positive electrode sheet 210 and the negative electrode sheet 220 for insulation, and is not shown in fig. 2 for clearly showing the structure.
In one example, the positive electrode tab 210 includes a current collector and a positive active material coated on the current collector. The current collector of the positive plate 210 is aluminum foil, and the positive active material is lithium cobaltate LiCoO2Lithium manganate LiMn2O4, lithium iron phosphate LiFePO4 and the like. The positive electrode tab 210 is shown in solid lines in fig. 2 for clarity of illustration.
In one example, the negative electrode tab 220 includes a current collector and a negative active material coated on the current collector. The current collector of the negative plate 220 is copper foil, and the negative active material is graphite or lithium titanate Li2TiO3And the like. The negative electrode tab 220 is shown in fig. 2 using a dotted line for clarity of the structure.
It is understood that the current collector may be coated on one side or both sides when the active material is coated. Therefore, in the embodiment of the present disclosure, the positive electrode sheet 210 and the negative electrode sheet 220 include a single-coated region, a double-coated region, and a blank coated region in a direction from the leading end to the trailing end of the winding. The single-coated region means that one side of the current collector is coated with the active material and the other side is not coated with the active material. The double-coated area means that active materials are coated on both sides of the current collector. The blank coating region means that the active material is not coated on both sides of the current collector. As shown in fig. 2, the structures of different coating regions are clearly shown by the thick lines.
As shown in fig. 2, in the present embodiment, the positive electrode sheet 210 (solid line in the drawing) includes a tab welding region, a double-coated region, and a single-coated region in this order from the winding head end to the winding tail end. The tab welding region of the positive electrode tab 210 may be not coated with an active material and used to weld the positive electrode tab 211. The negative electrode sheet 220 (dotted line in the drawing) includes a tab welding region, a single-coated region, a double-coated region, and a blank coated region in this order from the winding head end to the winding tail end. The tab welding region of the negative electrode tab 220 may be not coated with an active material and used to weld the negative electrode tab 221.
When the cell is wound, the winding of the negative electrode sheet 220 is started with the negative electrode sheet located inside the positive electrode sheet 210. The tab welding region of the positive electrode tab 210 and the tab welding region of the negative electrode tab 220 are stacked to form the first turn of winding of the cell structure, i.e., the innermost turn of winding in fig. 2. The double-coated region of the positive electrode tab 210 and the single-coated region of the negative electrode tab 220 form a second turn of the cell structure winding, in which the coating direction of the active material of the single-coated region of the negative electrode tab 220 is directed toward the positive electrode tab 210, thereby forming a lithium ion movement path opposite to the positive electrode tab 210. The one-side coated region of the positive electrode sheet 210 and the two-side coated region of the negative electrode sheet 220 form a third turn of the cell structure winding in which the coating direction of the active material of the one-side coated region of the positive electrode sheet 210 is directed toward the negative electrode sheet 220, thereby forming a lithium ion moving path opposite to the negative electrode sheet 220.
During the last winding, the blank coating area of the negative electrode sheet 220 is coated and wound for one circle, so that the blank coating area of the negative electrode sheet 220 and the single-side coating area of the positive electrode sheet 210 form a last waistcoat structure, and the use safety of the battery cell is ensured.
Referring to fig. 2, in the present embodiment, the length of the blank coating area of the negative electrode sheet 220 is greater than the length of the single-side coating area of the positive electrode sheet 210, so that the blank coating area of the negative electrode sheet 220 can be coated on the positive electrode sheet 210 during cell encapsulation, thereby improving the cell safety.
In this embodiment, the length of the blank coating area of the negative electrode sheet 220 is one circle of the winding of the battery cell structure, so that the coverage area of the waistcoat structure area is increased, and the waistcoat structure can play a good protection role when any position of the battery is damaged by impact and through nails.
It can be understood that the cell structure of the embodiment of the present disclosure is a vest structure formed by using the single-sided coating region of the first pole piece and the blank coating region of the second pole piece, which increases the energy density of the battery, and thus, there is no need to limit the length of the vest structure. That is, in the embodiment of fig. 2, the length of the single-coated region of the positive electrode sheet 210 and the length of the blank coated region of the negative electrode sheet 220 are not necessarily limited, and may be a winding half turn, 0.75 turn, one turn, or the like. In some embodiments, the waistcoat structure of the cell structure covers at least half of the winding, so as to ensure the protection effect on the cell. It will be appreciated by those skilled in the art that the present disclosure is not described in detail herein.
In the present embodiment, when the positive electrode sheet 210 and the negative electrode sheet 220 are wound, a separator is always required to be provided between the two for insulation, and although the separator is not shown in fig. 2, it should be understood by those skilled in the art that the present disclosure is not repeated.
As shown in fig. 2, the cell structure further includes a positive tab 211 welded to the positive plate 210, and a negative tab 221 welded to the negative plate 220. The positive and negative electrode tabs are used for connecting the tabs serving as the positive and negative electrodes of the battery with an external circuit after the battery core is packaged. It will be appreciated by those skilled in the art that the present disclosure is not described in detail herein.
Therefore, the battery core structure of the embodiment of the disclosure forms the vest structure by using the blank coating area of the second pole piece and the single-side coating area of the first pole piece, so as to improve the safety of the battery when the battery is damaged by impact, through-nails and the like. Meanwhile, the active substance is coated on the single surface of the first pole piece of the waistcoat structure, so that energy can be provided for the battery and the energy density of the battery can be improved under the condition of the same battery cell thickness compared with the traditional waistcoat structure.
In a second aspect, embodiments of the present disclosure provide a lithium ion battery, and the lithium ion battery may include the cell structure in any of the above embodiments.
In some embodiments, as shown in fig. 2, positive and negative electrode sheets of the battery are wound according to the embodiment of fig. 2, and filled with an electrolyte for encapsulation to form a finished battery structure. It will be appreciated by those skilled in the art that the present disclosure is not described in detail herein.
In a third aspect, the present disclosure provides an electronic device, which includes the above lithium ion battery. Such as smart phones, tablets, wearable devices, etc., to which the present disclosure is not limited.
In the battery and the electronic device according to the embodiments of the present disclosure, the cell structure forms the vest structure by using the blank coating area of the second pole piece and the single-side coating area of the first pole piece, so as to improve the safety of the battery when the battery is damaged by impact, nail penetration, and the like. Meanwhile, the active substance is coated on the single surface of the first pole piece of the waistcoat structure, so that energy can be provided for the battery and the energy density of the battery can be improved under the condition of the same battery cell thickness compared with the traditional waistcoat structure.
It should be understood that the above embodiments are only examples for clearly illustrating the present invention, and are not intended to limit the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the present disclosure may be made without departing from the scope of the present disclosure.

Claims (10)

1. A cell structure, comprising:
the battery cell structure comprises a first pole piece and a second pole piece, wherein the first pole piece and the second pole piece are stacked and wound to form the battery cell structure;
the current collector at the winding tail end of the first pole piece is provided with a single-surface coating area, and the coating direction of the single-surface coating area faces the inner side of the winding direction; the winding tail end of the second pole piece is provided with a blank coating area, and the blank coating area is coated on the winding outer side of the single-surface coating area.
2. The cell structure of claim 1,
the length of the blank coating area is not less than that of the single-side coating area.
3. The cell structure of claim 1,
the length of the blank coating area is at least half of the winding of the cell structure.
4. The cell structure of claim 3,
the length of the blank coating area is one circle of the winding of the battery cell structure.
5. The cell structure of claim 1,
the winding head end of the second pole piece is positioned on the inner side of the winding head end of the first pole piece;
the first pole piece sequentially comprises a tab welding area, a double-sided coating area and a single-sided coating area from the head end to the tail end;
the second pole piece sequentially comprises a pole lug welding area, a single-side coating area, a double-side coating area and the blank coating area from the head end to the tail end.
6. The cell structure of claim 5,
the tab welding area of the first pole piece and the tab welding area of the second pole piece are stacked to form a first circle of the cell structure winding, the double-sided coating area of the first pole piece and the single-sided coating area of the second pole piece form a second circle of the cell structure winding, the single-sided coating area of the first pole piece and the double-sided coating area of the second pole piece form a third circle of the cell structure winding, and the blank coating area of the second pole piece is wrapped and wound on the outer side of the third circle of the winding structure.
7. The cell structure of any of claims 1 to 6,
the first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.
8. The cell structure of claim 1, further comprising:
the first tab is welded at the winding head end of the first pole piece;
the second tab is welded at the winding head end of the second pole piece; and
and the diaphragm is arranged between the first pole piece and the second pole piece.
9. A lithium ion battery comprising the cell structure of any of claims 1 to 8.
10. An electronic device characterized by comprising the lithium ion battery according to claim 9.
CN202120411121.0U 2021-02-24 2021-02-24 Battery cell structure, lithium ion battery and electronic equipment Active CN215008283U (en)

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CN202120411121.0U CN215008283U (en) 2021-02-24 2021-02-24 Battery cell structure, lithium ion battery and electronic equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202120411121.0U CN215008283U (en) 2021-02-24 2021-02-24 Battery cell structure, lithium ion battery and electronic equipment

Publications (1)

Publication Number Publication Date
CN215008283U true CN215008283U (en) 2021-12-03

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