Battery cell, battery and electric equipment

Abstract

The utility model discloses an electrical core, a battery and electric equipment, the electrical core comprises a positive plate, a negative plate and a diaphragm, the diaphragm is located between the positive plate and the negative plate, and the positive plate and the negative plate are laminated and then wound to form the electrical core; the positive plate comprises a first section and a second section which are connected with each other, positive active material layers are arranged on the two sides of the first section in the thickness direction, the positive active material layers are arranged on the side, close to the negative plate, of the second section, and the end, away from the second section, of the first section is a winding starting point of the positive plate; the diaphragm comprises a first area and a second area which are connected with each other, the first area covers the first section, the second area covers the second section and part of the first section, and the viscosity of the first area is greater than that of the second area. According to the battery cell disclosed by the utility model, the risk of breaking the positive plates can be effectively avoided.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery cell, a battery and an electrical device. Background Technology

[0002] In related technologies, a battery cell includes a positive electrode, a separator, and a negative electrode. The separator is located between the positive and negative electrode, and the positive electrode, separator, and negative electrode are stacked and wound together to form the battery cell. During cycling, the adhesion between the separator and the positive and negative electrode is relatively tight. When the negative electrode expands, this can cause the separator to pull on the positive electrode, increasing the risk of the positive electrode breaking. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a battery cell that can effectively avoid the risk of positive electrode breakage.

[0004] This utility model also proposes a battery.

[0005] This utility model also proposes an electrical device.

[0006] According to a first aspect of the present invention, a battery cell includes a positive electrode, a negative electrode, and a separator, wherein the separator is located between the positive electrode and the negative electrode, and the positive electrode and the negative electrode are stacked and then wound to form the battery cell.

[0007] The positive electrode sheet includes a first segment and a second segment connected to each other. The first segment has positive active material layers on both sides in the thickness direction. The second segment has the positive active material layer on the side closer to the negative electrode sheet. The end of the first segment away from the second segment is the starting point for winding the positive electrode sheet.

[0008] The diaphragm includes a first region and a second region that are interconnected. The first region covers the first segment, and the second region covers the second segment and a portion of the first segment. The adhesiveness of the first region is greater than that of the second region.

[0009] The battery cell according to the embodiments of this utility model has at least the following beneficial effects: a positive active material layer is provided on the second segment. In the prior art, the separator is adhesive and will adhere to the positive electrode sheet. When the negative electrode sheet expands, the negative electrode sheet will pull the separator to pull the positive electrode sheet, causing the junction of the second segment and the first segment to break, or causing the second segment to break. In this application, the second region covers the second segment and part of the first segment. The adhesiveness of the second region is less than that of the first region. That is, the adhesion strength of the second region to the second segment and part of the first segment is smaller. Therefore, the pulling force of the separator on the positive electrode sheet is lower, which can effectively avoid the risk of the positive electrode sheet breaking. Specifically, the battery cell can effectively avoid the risk of the positive electrode sheet breaking.

[0010] According to some embodiments of the present invention, the viscosity value of the second region of the battery cell is A, where 0 N / m < A ≤ 20 N / m.

[0011] According to some embodiments of the present invention, the first region of the battery cell includes a base layer and a first coating layer, wherein the first coating layer is connected to the base layer and the material of the first coating layer is polyvinylidene fluoride.

[0012] According to some embodiments of the present invention, the positive electrode further includes a third segment, the two ends of the second segment are respectively connected to the first segment and the third segment, the third segment does not have the positive electrode active material layer, and the end of the third segment away from the second segment is the winding end point of the positive electrode.

[0013] According to some embodiments of the present invention, in the battery cell, along the winding direction of the battery cell, the second region covers the first segment by a size B, where 1mm ≤ B ≤ 3mm.

[0014] According to some embodiments of the present invention, the second region of the battery cell includes a base layer and a second coating layer, the second coating layer being connected to the base layer, and the material of the second coating layer being ceramic or silicon dioxide.

[0015] According to some embodiments of the present invention, the second region of the battery cell includes a base layer and a second coating layer, the second coating layer being connected to the base layer, and the material of the second coating layer being PP or PE.

[0016] According to some embodiments of the present invention, the negative electrode includes a fourth segment, a fifth segment, and a sixth segment. The two ends of the fifth segment are connected to the fourth segment and the sixth segment, respectively. A negative electrode active material layer is provided on the side of the fourth segment near the positive electrode. The negative electrode active material layer is provided on both sides of the fifth segment in the thickness direction. The sixth segment does not have a negative electrode active material layer. The end of the fourth segment away from the fifth segment is the starting point of the winding of the negative electrode, and the end of the sixth segment away from the fifth segment is the ending point of the winding of the negative electrode.

[0017] The battery according to the second aspect embodiment of the present invention includes the battery cell described in any one of the first aspect embodiments.

[0018] The battery according to the embodiments of this utility model has at least the following beneficial effects: A positive electrode active material layer is disposed on the second section. In the prior art, the separator is adhesive and adheres to the positive electrode sheet. When the negative electrode sheet expands, it pulls the separator, causing the positive electrode sheet to break, either at the junction of the second and first sections or at the second section itself. In this application, the second region covers the second section and part of the first section. The adhesiveness of the second region is less than that of the first region; that is, the adhesion strength of the second region to the second section and part of the first section is lower. Therefore, the pulling force of the separator on the positive electrode sheet is lower, effectively avoiding the risk of the positive electrode sheet breaking. Specifically, the battery cell can effectively avoid the risk of the positive electrode sheet breaking. Furthermore, the battery has higher reliability.

[0019] The electrical device according to a third aspect embodiment of the present invention includes the battery described in the second aspect embodiment.

[0020] The electrical device according to the embodiments of this utility model has at least the following beneficial effects: A positive electrode active material layer is provided on the second section. In the prior art, the separator is adhesive and adheres to the positive electrode sheet. When the negative electrode sheet expands, it pulls the separator, causing the positive electrode sheet to break, either at the junction of the second and first sections or at the second section itself. In this application, the second region covers the second section and part of the first section. The adhesiveness of the second region is less than that of the first region; that is, the adhesion strength of the second region to the second section and part of the first section is lower. Therefore, the pulling force of the separator on the positive electrode sheet is lower, effectively avoiding the risk of the positive electrode sheet breaking. Specifically, the battery cell can effectively avoid the risk of the positive electrode sheet breaking. Furthermore, the battery has higher reliability. Even further, the electrical device with this battery has better safety.

[0021] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0023] Figure 1 This is a schematic diagram of a battery cell according to some embodiments of the present invention;

[0024] Figure 2 This is a top view of the separator in the battery cell according to some embodiments of the present invention;

[0025] Figure 3 This is a cross-sectional view of the separator in the battery cell of some embodiments of this utility model.

[0026] Figure label:

[0027] Cell 10, positive electrode 100, first section 110, second section 120, third section 130, negative electrode 200, fourth section 210, fifth section 220, sixth section 230, separator 300, first zone 310, second zone 320, base layer 400, first coating 500, second coating 600. Detailed Implementation

[0028] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0029] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0030] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0031] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0032] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0033] In related technologies, a battery cell includes a positive electrode, a separator, and a negative electrode. The separator is located between the positive and negative electrode, and the positive electrode, separator, and negative electrode are stacked and wound together to form the battery cell. During cycling, the adhesion between the separator and the positive and negative electrode is relatively tight. When the negative electrode expands, this can cause the separator to pull on the positive electrode, increasing the risk of breakage. Typically, the breakage occurs in the single-layer fabric area of ​​the positive electrode or at the boundary between the double-layer and single-layer fabric areas. Therefore, this application proposes a battery cell.

[0034] Please refer to Figure 1 and Figure 2 In some embodiments, the battery cell 10 includes a positive electrode 100, a negative electrode 200, and a separator 300. The separator 300 is located between the positive electrode 100 and the negative electrode 200, and can physically separate the positive and negative electrodes to prevent them from directly contacting each other and causing a short circuit. There may be two separators 300, with the two separators 300 located on opposite sides of the positive electrode 100, thereby achieving isolation between the positive electrode 100 and the negative electrode 200. The positive electrode 100 and the negative electrode 200 are stacked and then wound to form the battery cell 10. Since the separator 300 is located between the positive electrode 100 and the negative electrode 200, the stacking of the positive electrode 100 and the negative electrode 200 can specifically be in the order of positive electrode 100, separator 300, negative electrode 200, and separator 300 stacked sequentially. The specific structure of the positive electrode 100 is described below. The positive electrode 100 includes a first segment 110, a second segment 120, and a third segment 130. The two ends of the second segment 120 are connected to the first segment 110 and the third segment 130, respectively. Positive active material layers are disposed on both sides of the first segment 110 in the thickness direction. A positive active material layer is disposed on the side of the second segment 120 closer to the negative electrode 200. The third segment 130 does not have a positive active material layer. The end of the first segment 110 furthest from the second segment 120 is the starting point of the winding of the positive electrode 100, and the end of the third segment 130 furthest from the second segment 120 is the ending point of the winding of the positive electrode 100. Specifically, the starting point of winding refers to the end from which the positive electrode 100 begins to be wound. The ending point of winding refers to the end from which the positive electrode 100 ends after winding.

[0035] The specific structure of diaphragm 300 is described below. Please refer to [link / reference]. Figure 2The separator 300 includes a first region 310 and a second region 320 that are interconnected. That is, along the length of the separator 300, the separator 300 is divided into a first region 310 and a second region 320. The adhesiveness of the first region 310 is greater than that of the second region 320. Specifically, the first region 310 has greater adhesiveness, and the positive electrode 100 and the negative electrode 200 are respectively bonded to both sides of the first region 310. This can effectively prevent the separator 300, the positive electrode 100, and the negative electrode 200 from misaligning with each other, thereby improving assembly accuracy. It should be noted that the adhesiveness of the first region 310 can improve the performance of the cell 10. In addition, there are positive active material layers on both sides of the first segment 110, so even if the separator 300 is bonded to the first segment 110, the first segment 110 is not prone to breakage. The second zone 320 covers the second segment 120 and the third segment 130, and the second zone 320 covers part of the first segment 110. The viscosity value of the second zone 320 is A, 0 N / m ≤ A ≤ 20 N / m. Specifically, a positive electrode active material layer is provided on the second segment 120, while no positive electrode active material layer is provided on the third segment 130. In the prior art, the separator 300 is adhesive and will adhere to the positive electrode 100. When the negative electrode 200 expands, the negative electrode 200 will cause the separator 300 to pull the positive electrode 100, resulting in breakage at the junction of the second segment 120 and the first segment 110, or breakage at the second segment 120. In this application, the second region 320 covers the second segment 120, the third segment 130, and part of the first segment 110. That is, the adhesion strength of the second region 320 to the second segment 120 and the first segment 110 is small. Therefore, the pulling force of the separator 300 on the positive electrode 100 is low, which can effectively avoid the risk of the positive electrode 100 breaking. Specifically, the cell 10 can effectively avoid the risk of the positive electrode 100 breaking.

[0036] The following continues the explanation of the separator 300. The viscosity value of the second region 320 is A, where 0 N / m ≤ A ≤ 20 N / m. Specifically, the viscosity value of the second region 320 can be A equal to 0 N / m, 1 N / m, 2 N / m, 3 N / m, 4 N / m, 5 N / m, 6 N / m, 7 N / m, 8 N / m, 9 N / m, 10 N / m, 11 N / m, 12 N / m, 13 N / m, 14 N / m, 15 N / m, 16 N / m, 17 N / m, 18 N / m, 19 N / m, or 20 N / m. When A equals 0 N / m, it means that the second region 320 has no viscosity. When the second region 320 comes into contact with the positive electrode 100, the separator 300 will not pull on the positive electrode 100, thus effectively avoiding the risk of breakage of the positive electrode 100. Furthermore, when the maximum value of A exceeds 20 N / m, the adhesion between the second region 320 and the positive electrode 100 becomes too great, causing the separator 300 to pull on the positive electrode 100, leading to its breakage. To further explain, to effectively prevent the positive electrode 100 from breaking, the positive current collector can be thickened, i.e., the aluminum foil can be thickened. However, this results in a lower energy density for the cell 10. In this application, the breakage problem can be effectively solved by changing the structure of the separator 300, without the need to thicken the positive current collector, thus avoiding a lower energy density for the cell 10.

[0037] Furthermore, the specific structure of Zone 310 is described below; please refer to [the relevant documentation]. Figure 2 and Figure 3 In some embodiments, the first region 310 includes a base layer 400 and a first coating 500, the first coating 500 being attached to the base layer 400 and made of polyvinylidene fluoride (PVDF). The base layer 400 can be made of PP or PE, and its surface has a porous structure that allows ions to pass through. After the PVDF is applied to the base layer 400, the first region 310 becomes adhesive.

[0038] Furthermore, to more effectively prevent breakage at the junction of the second segment 120 and the first segment 110, the second region 320 can cover a portion of the first segment 110, thereby completely covering the junction of the first segment 110 and the second segment 120. This arrangement also improves assembly tolerance and effectively increases manufacturing efficiency. Therefore, in some embodiments, the second region 320 also covers a portion of the first segment 110.

[0039] Furthermore, in some embodiments, along the winding direction of the cell 10, the second region 320 covers the first segment 110 by a dimension B, where 1mm ≤ B ≤ 3mm. Specifically, the winding direction of the cell 10 can be from the first segment 110 to the third segment 130. B can specifically be 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, or 3.0mm. When B is less than 1mm, higher assembly precision is required to ensure the second region 320 completely covers the second segment 120, which reduces manufacturing efficiency. If B is greater than 1mm, the assembly precision can be reduced, thus ensuring that the second region 320 completely covers the second segment 120 while covering the first segment 110. When B is greater than 3mm, there may be insufficient local dynamic performance, which may affect the cell 10 cycle interface.

[0040] Furthermore, the specific structure of Zone 320 is described below; please refer to [the relevant documentation]. Figure 2 and Figure 3 In some embodiments, the second region 320 includes a base layer 400 and a second coating 600, the second coating 600 being attached to the base layer 400. The material of the second coating 600 is ceramic or silica. The base layer 400 can be made of PP or PE, and its surface has a porous structure, allowing ions to pass through. After the ceramic or silica coating is applied to the base layer 400, the second region 320 is non-adhesive. That is, the diaphragm 300 structure of this application has a first region 310 that is adhesive, while the second region 320 is non-adhesive.

[0041] Furthermore, the following describes the additional structure of Zone 320; please refer to [the relevant documentation]. Figure 2 and Figure 3 In some embodiments, the second region 320 includes a base layer 400 and a second coating 600, the second coating 600 being attached to the base layer 400 and made of PP or PE. The base layer 400, also made of PP or PE, has a porous surface that allows ions to pass through. The second coating 600 has a larger particle size; its placement on the base layer 400 creates a porous structure in the separator 300, reducing the risk of breakage of the positive electrode 100. In other embodiments, the second region 320 includes only the base layer 400 without any coating. The base layer 400 itself is non-adhesive.

[0042] Furthermore, the specific structure of the negative electrode 200 is described below. Please refer to [link / reference]. Figure 1In some embodiments, the negative electrode 200 includes a fourth segment 210, a fifth segment 220, and a sixth segment 230. The two ends of the fifth segment 220 are connected to the fourth segment 210 and the sixth segment 230, respectively. A negative electrode active material layer is disposed on the side of the fourth segment 210 closest to the positive electrode 100. Negative electrode active material layers are disposed on both sides of the fifth segment 220 in the thickness direction, while the sixth segment 230 does not have a negative electrode active material layer. The end of the fourth segment 210 furthest from the fifth segment 220 is the starting point for winding the negative electrode 200, and the end of the sixth segment 230 furthest from the fifth segment 220 is the ending point for winding the negative electrode 200. Specifically, the starting point for winding refers to the end from which the negative electrode 200 begins to be wound. Specifically, the ending point for winding refers to the end from which the negative electrode 200 is finished after winding.

[0043] In some embodiments, the battery includes the cell 10 of any of the above embodiments. Specifically, a positive active material layer is provided on the second segment 120, and no positive active material layer is provided on the third segment 130. In the prior art, the separator 300 is adhesive and will adhere to the positive electrode 100. When the negative electrode 200 expands, the negative electrode 200 drives the separator 300 to pull the positive electrode 100, causing the junction of the second segment 120 and the first segment 110 to break, or causing the second segment 120 to break. In this application, the second region 320 covers the second segment 120, the third segment 130 and part of the first segment 110. That is, the adhesion strength of the second region 320 to the second segment 120 and the first segment 110 is small. Therefore, the pulling force of the separator 300 on the positive electrode 100 is low, which can effectively avoid the risk of the positive electrode 100 breaking. Specifically, the cell 10 can effectively avoid the risk of the positive electrode 100 breaking. Furthermore, the battery has high reliability.

[0044] In some embodiments, the electrical device includes the battery of the above embodiments. Specifically, a positive electrode active material layer is provided on the second segment 120, and no positive electrode active material layer is provided on the third segment 130. In the prior art, the separator 300 is adhesive and will adhere to the positive electrode 100. When the negative electrode 200 expands, the negative electrode 200 drives the separator 300 to pull the positive electrode 100, causing the junction of the second segment 120 and the first segment 110 to break, or causing the second segment 120 to break. In this application, the second region 320 covers the second segment 120, the third segment 130 and part of the first segment 110. That is, the adhesion strength of the second region 320 to the second segment 120 and the first segment 110 is small. Therefore, the pulling force of the separator 300 on the positive electrode 100 is low, which can effectively avoid the risk of the positive electrode 100 breaking. Specifically, the cell 10 can effectively avoid the risk of the positive electrode 100 breaking. Furthermore, the battery has high reliability. Even further, electrical devices using this battery offer good safety.

[0045] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A battery cell, characterized in that, include: A positive electrode, a negative electrode, and a separator, wherein the separator is located between the positive electrode and the negative electrode, and the positive electrode and the negative electrode are stacked and wound to form the battery cell; The positive electrode sheet includes a first segment and a second segment connected to each other. The first segment has positive active material layers on both sides in the thickness direction. The second segment has the positive active material layer on the side closer to the negative electrode sheet. The end of the first segment away from the second segment is the starting point for winding the positive electrode sheet. The diaphragm includes a first region and a second region that are interconnected. The first region covers the first segment, and the second region covers the second segment and a portion of the first segment. The adhesiveness of the first region is greater than that of the second region.

2. The battery cell according to claim 1, characterized in that, The viscosity value of the second region is A, where 0 N / m < A ≤ 20 N / m.

3. The battery cell according to claim 2, characterized in that, The first region includes a base layer and a first coating layer, the first coating layer being connected to the base layer, and the material of the first coating layer being polyvinylidene fluoride.

4. The battery cell according to claim 1, characterized in that, The positive electrode sheet further includes a third segment, with the two ends of the second segment connected to the first segment and the third segment respectively. The third segment does not have the positive electrode active material layer, and the end of the third segment furthest from the second segment is the winding end point of the positive electrode sheet.

5. The battery cell according to claim 1, characterized in that, Along the winding direction of the battery cell, the second region covers the first segment by a size B, where 1mm ≤ B ≤ 3mm.

6. The battery cell according to claim 1, characterized in that, The second region includes a base layer and a second coating layer, the second coating layer being connected to the base layer, and the material of the second coating layer being ceramic or silicon dioxide.

7. The battery cell according to claim 1, characterized in that, The second area includes a base layer and a second coating layer, the second coating layer being connected to the base layer, and the material of the second coating layer being PP or PE.

8. The battery cell according to claim 1, characterized in that, The negative electrode sheet includes a fourth segment, a fifth segment, and a sixth segment. The two ends of the fifth segment are connected to the fourth segment and the sixth segment, respectively. The fourth segment has a negative electrode active material layer on the side closest to the positive electrode sheet. The fifth segment has a negative electrode active material layer on both sides in the thickness direction. The sixth segment does not have a negative electrode active material layer. The end of the fourth segment away from the fifth segment is the starting point of the winding of the negative electrode sheet, and the end of the sixth segment away from the fifth segment is the ending point of the winding of the negative electrode sheet.

9. A battery, characterized in that, The battery cell includes any one of claims 1 to 8.

10. Electrical equipment, characterized in that, Includes the battery as described in claim 9.

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