Pole piece for lithium battery and lithium battery with same

Abstract

The utility model discloses a pole piece for a lithium battery and the lithium battery with the pole piece, the pole piece comprises a pole piece body, and a first groove and a second groove are arranged on at least one side surface of the pole piece body in the thickness direction; the first grooves extend in the first direction and are arranged at intervals in the second direction, and each first groove is provided with at least one bent part protruding in the second direction; and the second grooves extend in the second direction and are respectively communicated with the plurality of first grooves. According to the pole piece designed by the utility model, the surface of at least one side of the pole piece body in the thickness direction is provided with the first groove and the second groove, the first groove and the second groove can improve the infiltration rate of the pole piece, and meanwhile, electrolyte can be stored in the first groove and the second groove; and the electrolyte preservation amount of the part, which is not in contact with the electrolyte, of the pole piece is increased.

Description

Technical Field

[0001] The utility model relates to the field of lithium batteries, in particular to a pole piece for a lithium battery and a lithium battery having the pole piece. Background Art

[0002] In the related art, when lithium-ion batteries are working, lithium ions shuttle between the positive electrode plate, the negative electrode plate and the diaphragm through the electrolyte. The sufficient electrolyte content in the electrode plate plays a vital role in the performance of the battery. In the prior art, newly produced batteries may have the problem of poor wettability of the electrolyte in the electrode plate. Once such batteries are used, lithium deposition may occur, and even cause a short circuit between the positive and negative electrodes, thereby causing safety problems; as the number of charge and discharge times of lithium-ion batteries increases, the electrolyte will gradually be consumed, and due to the influence of its own gravity, the upper part of the electrode plate cannot contact the electrolyte, resulting in insufficient electrolyte content, which will lead to lithium deposition problems in the later stage of the battery, and thus bring safety hazards. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the utility model is to propose a pole piece for a lithium battery. According to the pole piece designed by the utility model, at least one side surface of the pole piece body in the thickness direction is provided with a first groove and a second groove, and the first groove and the second groove can increase the wetting rate of the pole piece, and at the same time, the first groove and the second groove can store electrolyte, thereby increasing the amount of electrolyte retained in the portion of the pole piece that is not in contact with the electrolyte.

[0004] The utility model also provides a lithium battery having the pole piece.

[0005] According to the utility model, the pole piece includes: a pole piece body, and a first groove and a second groove are arranged on at least one side surface of the pole piece body in the thickness direction; the first groove is constructed to extend in the first direction and be arranged at intervals in the second direction, and each of the first grooves is provided with at least one bent portion protruding in the second direction; the second groove extends in the second direction and is respectively connected with multiple first grooves.

[0006] According to the pole piece of the utility model, at least one side surface of the pole piece body in the thickness direction is provided with a first groove and a second groove. When producing batteries, the first groove and the second groove can allow the electrolyte to quickly cover the pole piece body, thereby improving the wetting rate of the pole piece and avoiding the problem of lithium deposition in the battery due to poor electrolyte wettability of the pole piece of the newly produced battery. At the same time, when the electrolyte is consumed, the first groove and the second groove of the pole piece can store electrolyte, thereby increasing the amount of electrolyte retained in the part of the pole piece that is not in contact with the electrolyte, thereby avoiding the problem of lithium deposition in the battery in the later stage and extending the service life of the battery.

[0007] According to some embodiments of the present invention, the second direction is a height direction and the bent portion has a connecting portion located at the highest point in the second direction, and the second groove extends to the connecting portion and is connected to the first groove through the connecting portion.

[0008] According to some embodiments of the present invention, the bent portion is configured as a plurality of portions spaced apart in the first direction, and the second groove is configured as a plurality of portions and is disposed in one-to-one correspondence with the connecting portions of the plurality of bent portions.

[0009] According to some embodiments of the present invention, the width of the first groove is w1, the depth of the first groove is h1, and the following conditions are met: 2≤w1 / h1≤20; the width of the second groove is w2, the depth of the second groove is h2, and the following conditions are met: 1≤w2 / h2≤10.

[0010] According to some embodiments of the present invention, the width of the first groove is w1, which satisfies: 100um≤w1≤200um.

[0011] According to some embodiments of the present invention, the depth of the first groove is h1, which satisfies: 10um≤h1≤50um.

[0012] According to some embodiments of the present invention, the width of the second groove is w2, which satisfies: 50um≤w2≤100um.

[0013] According to some embodiments of the present invention, the depth of the second groove is h2, which satisfies: 10um≤h2≤50um.

[0014] According to some embodiments of the utility model, a slurry coating is provided on the pole piece body, and the slurry coating is made of negative electrode active material graphite, a conductive agent, a dispersant and an adhesive.

[0015] The following briefly describes a lithium battery according to another embodiment of the present invention.

[0016] The lithium battery according to the utility model includes the pole piece described in any one of the above embodiments. Since the lithium battery according to the utility model is provided with the pole piece of the above embodiment, the pole piece of the lithium battery has good wettability, so that the lithium battery has good safety and long service life.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 It is a schematic diagram of a first wave-shaped groove being arranged on a pole piece body according to an embodiment of the utility model;

[0020] Figure 2 It is a schematic diagram of a first folded line groove provided on a pole piece body according to an embodiment of the utility model;

[0021] Figure 3 It is a schematic diagram of providing an arc-shaped first groove on a pole piece body according to an embodiment of the utility model.

[0022] Figure numerals: 10, pole piece body; 11, first groove; 12, second groove. DETAILED DESCRIPTION

[0023] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0026] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0028] In the related art, when lithium-ion batteries are working, lithium ions shuttle between the positive electrode plate, the negative electrode plate and the diaphragm through the electrolyte. The sufficient electrolyte content in the electrode plate plays a vital role in the performance of the battery. In the prior art, newly produced batteries may have the problem of poor wettability of the electrolyte in the electrode plate. Once such batteries are used, lithium deposition may occur, and even cause a short circuit between the positive and negative electrodes, thereby causing safety problems; as the number of charge and discharge times of lithium-ion batteries increases, the electrolyte will gradually be consumed, and due to the influence of its own gravity, the upper part of the electrode plate cannot contact the electrolyte, resulting in insufficient electrolyte content, which will lead to lithium deposition problems in the later stage of the battery, and thus bring safety hazards.

[0029] Reference below Figure 1-Figure 3 A pole piece for a lithium battery according to an embodiment of the utility model is described.

[0030] like Figure 1-Figure 3 As shown, the pole piece according to the utility model includes: a pole piece body 10, and a first groove 11 and a second groove 12 are provided on at least one side surface of the pole piece body 10 in the thickness direction; the first groove 11 is constructed to extend in the first direction and be spaced apart in the second direction, and each first groove 11 is provided with at least one curved portion protruding in the second direction; the second groove 12 extends in the second direction and is respectively connected with the plurality of first grooves 11.

[0031] It can be understood that the first direction can be constructed as the width direction of the pole piece, and the second direction can be constructed as the height direction of the pole piece. The pole piece can be constructed as the positive pole piece or the negative pole piece of the battery. The pole piece is vertically arranged in the battery and in contact with the electrolyte. When the battery is produced, the pole piece is first arranged in the battery, and then the electrolyte is injected into the battery. After the second groove 12 contacts the electrolyte, a capillary phenomenon occurs. Under the action of the capillary phenomenon, the electrolyte flows and rises along the extension direction of the second groove 12. When the electrolyte rises to the first groove 11, a capillary phenomenon occurs in the first groove 11. Under the action of the capillary phenomenon, the electrolyte flows along the extension direction of the first groove 11, so that the electrolyte can quickly cover the pole piece body 10, thereby improving the wetting efficiency of the pole piece and avoiding the problem of poor electrolyte wettability of the pole piece in the newly produced battery.

[0032] At the same time, as the number of times the battery is charged and discharged increases, the electrolyte is gradually consumed. Under the action of gravity, the top of the pole piece body cannot contact the electrolyte, that is, the amount of electrolyte above the pole piece is insufficient. When the electrolyte of the pole piece body 10 of the present application is consumed, due to the capillary phenomenon, the electrolyte will flow and rise along the extension direction of the second groove 12 of the present application. When the electrolyte rises to the first groove 11, it flows along the extension direction of the first groove 11. As a result, the first groove 11 and the second groove 12 of the portion of the pole piece body 10 that is not in contact with the electrolyte are both filled with electrolyte, increasing the amount of electrolyte in the portion of the pole piece that is not in contact with the electrolyte. At the same time, the curved portion can increase the length of the first groove 11, so that the portion of the pole piece body 10 that is not in contact with the electrolyte can retain more electrolyte, further increasing the amount of electrolyte in the pole piece.

[0033] It is worth noting that the first groove 11 and the second groove 12 may be provided on one side surface of the pole piece body 10 in the thickness direction; or the first groove 11 and the second groove 12 may be provided on both side surfaces of the pole piece body 10 in the thickness direction, which is not limited here.

[0034] According to the pole piece involved in the utility model, the pole piece body 10 is provided with a first groove 11 and a second groove 12 on at least one side surface in the thickness direction. When producing batteries, the first groove 11 and the second groove 12 can allow the electrolyte to quickly cover the pole piece body 10, thereby improving the wetting efficiency of the pole piece and avoiding the problem of lithium deposition in the battery due to poor electrolyte wettability of the pole piece of the newly produced battery. At the same time, when the electrolyte is consumed, the first groove 11 and the second groove 12 of the pole piece can store electrolyte, thereby increasing the amount of electrolyte retained in the portion of the pole piece body 10 that is not in contact with the electrolyte, thereby avoiding the problem of lithium deposition in the later stage of the battery and extending the service life of the battery.

[0035] According to some embodiments of the present invention, Figure 1-Figure 3As shown, the second direction is the height direction and the curved portion has a connecting portion located at the highest point in the second direction, and the second groove 12 extends to the connecting portion and is connected with the first groove 11 through the connecting portion. Therefore, when the second groove 12 contacts the electrolyte and generates a capillary phenomenon, the electrolyte will flow along the extension direction of the second groove 12 and rise to the connecting portion. Since the connecting portion is located at the highest point of the curved portion in the second direction, under the action of gravity, the flow speed of the electrolyte along the first groove 11 is increased, so that the electrolyte can be quickly stored in the first groove 11, thereby improving the wetting efficiency of the electrode.

[0036] According to some embodiments of the present invention, Figure 1-Figure 3 As shown, the bending portion is constructed as a plurality of portions spaced apart in a first direction, and the plurality of bending portions can increase the length dimension of the first groove 11, so that the first groove 11 can store more electrolyte, thereby increasing the electrolyte holding capacity of the electrode, and the second groove 12 is constructed as a plurality of portions and is arranged one-to-one with the connecting portions of the plurality of bending portions, and the plurality of second grooves 12 are all suitable for capillary phenomena when in contact with the electrolyte, thereby, the plurality of second grooves 12 are arranged on the electrode body 10, which can improve the efficiency of the electrolyte flowing to the first groove 11, thereby improving the wetting efficiency of the electrode, and at the same time, the plurality of second grooves 12 respectively correspond one-to-one with the connecting portions of the plurality of bending portions, thereby, when the electrolyte rises to the connecting portion along the extension direction of the plurality of second grooves 12, the electrolyte can flow rapidly along the bending portion under the action of gravity, thereby further improving the wetting efficiency of the electrode.

[0037] Preferably, the curved portions are continuously arranged to form a first groove 11 extending along the first direction, so that the first groove 11 can store more electrolyte, thereby increasing the amount of electrolyte held by the electrode sheet. In some embodiments, the continuously arranged curved portions can make the first groove 11 be configured as a wave shape extending along the first direction; can also make the first groove 11 be configured as a fold line shape extending along the first direction; can also make the first groove 11 be configured as an arc shape extending along the first direction.

[0038] According to some embodiments of the present invention, Figure 1-Figure 3As shown, the width of the first groove 11 is w1, and the depth of the first groove 11 is h1, which satisfies: 2≤w1 / h1≤20; the width of the second groove 12 is w2, and the depth of the second groove 12 is h2, which satisfies: 1≤w2 / h2≤10. The width w1 of the first groove 11 satisfies: 100um≤w1≤200um. It can be understood that w1 in the above range can increase the storage capacity of the electrode liquid stored in the first groove 11, thereby increasing the electrolyte retention of the electrode. The depth h1 of the first groove 11 satisfies: 10um≤h1≤50um. It can be understood that the electrode body 10 has a certain thickness. In order to avoid the first groove 11 from being too large in depth and affecting the structural strength of the electrode body 10, the present application makes h1≤50um, and in order to ensure that the first groove 11 can store more electrolyte, the present application makes 10um≤h1, preferably, h1=20um.

[0039] According to some embodiments of the present invention, Figure 1-Figure 3 As shown, the width of the second groove 12 is w2, satisfying: 50um≤w2≤100um. It can be understood that the width of the second groove 12 is inversely proportional to the rising height and speed of the electrolyte in the capillary phenomenon. Therefore, the smaller the width of the second groove 12, the higher the rising height of the electrolyte along the extension direction of the second groove 12 and the faster the rising speed. The present application allows the electrolyte to quickly rise to the first groove 11 along the extension direction of the second groove 12 by setting 50um≤w2≤100um, thereby improving the wetting efficiency of the electrode piece, and at the same time, the second groove 12 can store more electrolyte, thereby increasing the electrolyte retention amount of the electrode piece.

[0040] According to some embodiments of the present invention, Figure 1-Figure 3 As shown, the depth of the second groove 12 is h2, which satisfies: 10um≤h2≤50um. It can be understood that the pole piece body 10 has a certain thickness. In order to avoid the second groove 12 having a too large depth and affecting the structural strength of the pole piece body 10, the present application sets h2≤50um. In order to ensure that the second groove 12 can store more electrolyte, the present application sets 10um≤h2. Preferably, h2=20um.

[0041] According to some embodiments of the present invention, Figure 1-Figure 3As shown, a slurry coating is provided on the pole piece body 10, and the slurry coating is made of negative electrode active material graphite, conductive agent, dispersant and adhesive. In some embodiments, the slurry coating is made of negative electrode active material graphite, conductive agent, dispersant and adhesive. The negative electrode active material graphite, conductive agent, dispersant and adhesive are dispersed in water according to a mass ratio of 96:1:1.5:1.5 to form a negative electrode slurry. The negative electrode slurry is applied to the pole piece body 10. After the negative electrode slurry is dried, a slurry coating is formed on the pole piece body 10. The pole piece body 10 and the slurry coating are sufficient to jointly define a negative electrode piece.

[0042] The lithium battery according to the present utility model is briefly described below.

[0043] The lithium battery according to the utility model is provided with the pole piece of the above-mentioned embodiment. Since the lithium battery according to the utility model is provided with the pole piece described in any one of the above-mentioned embodiments, the pole piece of the lithium battery has good wettability, so that the lithium battery has good safety and long service life.

[0044] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. 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 this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0045] Although embodiments of the present invention have been shown and described above, changes, modifications, substitutions and variations may be made to the embodiments described above.

Claims

1. A pole piece for a lithium battery, characterized in that: include: A pole piece body, wherein at least one side surface of the pole piece body in the thickness direction is provided with a first groove and a second groove; The first groove is configured to be a plurality of grooves extending in the first direction and arranged at intervals in the second direction, and each of the first grooves is provided with at least one curved portion protruding in the second direction; The second grooves extend in the second direction and are respectively connected to the first grooves.

2. The pole piece for lithium battery according to claim 1, characterized in that: The second direction is a height direction and the bent portion has a connecting portion located at the highest point in the second direction, and the second groove extends to the connecting portion and is connected to the first groove through the connecting portion.

3. The pole piece for lithium battery according to claim 2, characterized in that: The bent portions are configured to be a plurality of portions spaced apart from each other in the first direction, and the second grooves are configured to be a plurality of portions and are disposed in a one-to-one correspondence with the connection portions of the plurality of bent portions.

4. The pole piece for lithium battery according to claim 1, characterized in that: The width of the first groove is w1, and the depth of the first groove is h1, which satisfies: 2≤w1 / h1≤20; The width of the second groove is w2, and the depth of the second groove is h2, which satisfies: 1≤w2 / h2≤10.

5. The pole piece for lithium battery according to claim 4, characterized in that: The width of the first groove is w1, which satisfies: 100um≤w1≤200um.

6. The pole piece for lithium battery according to claim 5, characterized in that: The depth of the first groove is h1, which satisfies: 10um≤h1≤50um.

7. The pole piece for lithium battery according to claim 4, characterized in that: The width of the second groove is w2, which satisfies: 50um≤w2≤100um.

8. The pole piece for lithium battery according to claim 7, characterized in that: The depth of the second groove is h2, which satisfies: 10um≤h2≤50um.

9. A lithium battery, characterized in that: A pole piece for a lithium battery comprising any one of claims 1 to 8.

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