Battery cell structure, battery and electric equipment

Abstract

The utility model discloses a battery cell structure, a battery and electric equipment. The battery cell structure comprises a winding battery cell. The winding battery cell comprises a first pole piece positioned on the outer layer, and a diaphragm and a second pole piece which are laminated with the first pole piece; the polarity of the first pole piece is different from that of the second pole piece; the first pole piece located on the outer layer comprises a first straight area and a first bent area which are connected with each other. Wherein a first junction position is arranged between the first straight area and the first bending area, a first reinforcing structure is also arranged at the first junction position of the winding battery cell, and the first reinforcing structure is connected with the first straight area and the first bending area. The scheme can effectively improve the tensile strength of the battery cell and improve the problem of lithium precipitation at the corner. Compared with the scheme that the tensile strength of the foil is enhanced by increasing the thickness of the foil, the scheme can effectively avoid the situation that the energy density of the battery cell is reduced after the thickness of the foil is increased, and the performance of the battery cell is guaranteed.

Description

Technical Field

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

[0002] Soft-pack prismatic cells typically use a winding method to combine the positive electrode, separator, and negative electrode to form a core. The core includes flat and bent sections, with the bent section prone to lithium plating. In high-silicon batteries, porous separators are used to improve the corner lithium plating problem. However, the space in the porous separator in the flat section is compressed after formation and hot pressing, while the bent section has reserved space, resulting in less expansion of the electrode in the bent section compared to the flat section. Therefore, at the boundary between the flat and bent sections, the ending foil is subjected to tension due to the difference in expansion, making foil breakage prone to occur at this boundary. Related technologies increase the foil thickness to enhance its tensile strength, but this increases the cell's energy density. Utility Model Content

[0003] The main purpose of this utility model is to propose a cell structure, battery and electrical equipment, which aims to solve the technical problem of foil breakage.

[0004] To achieve the above objectives, a first aspect of this utility model provides a battery cell structure, comprising:

[0005] A wound battery cell, the wound battery cell including a first electrode sheet located on the outer layer and a diaphragm and a second electrode sheet stacked on the first electrode sheet, the first electrode sheet and the second electrode sheet having opposite polarities; the first electrode sheet located on the outer layer includes a first straight region and a first bent region connected to each other;

[0006] The first straight area and the first bent area have a first boundary position. At the first boundary position, the wound cell is further provided with a first reinforcing structure, which connects the first straight area and the first bent area.

[0007] In some embodiments, the first electrode includes a second flat region connected to the first bending region, and along the thickness direction of the wound cell, the second flat region is located on the side of the first bending region opposite to the first flat region;

[0008] The second straight area and the first bent area have a second boundary position. At the second boundary position, the wound cell is also provided with a second reinforcing structure, which connects the second straight area and the first bent area.

[0009] In some embodiments, along the winding direction of the wound cell, the first reinforcing structure includes a first end away from the first bending region and a second end away from the first straight region, the first end being welded to the first straight region and the second end being welded to the first bending region, and the first reinforcing structure being made of a metallic material.

[0010] In some embodiments, the first bending region has an inflection point position away from the first straight region, the second end is located between the inflection point position and the first boundary position, and the second end is spaced apart from both the inflection point position and the first boundary position.

[0011] In some embodiments, the first end is located on the side away from the inflection point of the first boundary position, the first boundary position has a first boundary line parallel to the first straight area, along the thickness direction perpendicular to the wound cell, and the distance from the first end to the boundary line is L, wherein L satisfies: 1mm≤L≤2mm.

[0012] In some embodiments, along the winding direction of the wound cell, the extension length of the first reinforcing structure is D, and the thickness of the wound cell is T, satisfying: π×T / 4≤D≤π×1.14T / 4.

[0013] In some embodiments, the thickness of the first reinforcing structure is H, wherein H satisfies: 10μm≤H≤80μm.

[0014] In some embodiments, the first reinforcing structure and the second reinforcing structure are arranged opposite to each other along the thickness direction of the wound cell.

[0015] A second aspect of this utility model provides a battery, which includes the cell structure described in the above embodiments.

[0016] A third aspect of this utility model provides an electrical device, which includes the battery described in the above embodiments.

[0017] Compared with the prior art, the beneficial effects of this utility model include:

[0018] In the technical solution of this utility model, the cell structure includes a wound cell. The wound cell includes a first electrode sheet located on the outer layer and a separator and a second electrode sheet stacked on top of the first electrode sheet. The first electrode sheet and the second electrode sheet have opposite polarities. The first electrode sheet located on the outer layer includes a first straight region and a first bent region connected to each other. In the prior art, a porous separator is used in high-silicon batteries to improve the problem of lithium plating at corners. However, the space of the porous separator in the straight region is compressed after formation and hot pressing, while the bent region has reserved space because the porous separator has reserved space. The expansion of the electrode sheet in the bent region is relatively smaller than that in the straight region. Therefore, at the junction of the straight region and the bent region, the foil at the end will be stretched due to the difference in the size of the expansion, that is, the problem of foil breakage is likely to occur at this junction. In this solution, there is a first junction between the first straight region and the first bent region. At the first junction, the wound cell also has a first reinforcing structure. Therefore, even if the first electrode sheet on the outer layer breaks at the first junction, the cell can still perform charging and discharging operations because the first reinforcing structure connects the first straight area and the first bent area. This solution effectively improves the tensile strength of the cell and alleviates the problem of lithium plating at the corner. Compared to solutions that increase the foil thickness to enhance its tensile strength, this solution effectively avoids the situation where increasing the foil thickness reduces the energy density of the cell, thus ensuring cell performance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the battery cell structure in one embodiment of the present invention; wherein, the reinforcing structure is not shown.

[0021] Figure 2 This is a schematic diagram of the cell structure in one embodiment of the present invention; wherein, the first junction position, the second junction position, the third junction position and the fourth junction position are shown, and the reinforcing structure is not shown;

[0022] Figure 3 This is a schematic diagram of the cell structure in one embodiment of the present invention; wherein, a first reinforcing structure, a second reinforcing structure, a third reinforcing structure and a fourth reinforcing structure are shown.

[0023] Explanation of icon numbers:

[0024] Cell structure 10;

[0025] First electrode 100; First straight region 110; First bending region 120; Inflection point 121; First boundary position 130; First boundary line 131; First reinforcing structure 140; First end 141; Second end 142;

[0026] Second straight zone 150; Second boundary position 160; Second reinforcement structure 170; Third reinforcement structure 180;

[0027] Third boundary position 181; Fourth reinforcement structure 190; Fourth boundary position 191;

[0028] Diaphragm 200;

[0029] Second electrode 300.

[0030] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0032] The first aspect of this utility model provides a battery cell structure 10 that can effectively suppress foil breakage and ensure the energy density of the battery cell. See below for reference. Figures 1 to 3 The present application describes a battery cell structure 10 according to an embodiment. Specifically, the battery cell structure 10 includes a wound battery cell. The wound battery cell includes a first electrode 100, which is located on the outermost layer of the wound battery cell. It should be noted that in some embodiments, the first electrode 100 can be a positive electrode. In other embodiments, the first electrode 100 can also be a negative electrode. This embodiment uses the first electrode 100 as a negative electrode for illustration. The wound battery cell also includes a separator 200 and a second electrode 300 stacked with the first electrode 100. The second electrode 300 is located on the inner side of the wound battery cell, and the polarity of the second electrode 300 is different from that of the first electrode 100. This embodiment uses the second electrode 300 as a positive electrode for illustration.

[0033] Reference Figure 2 The first electrode 100 located on the outer layer includes a first flat region 110 and a first bent region 120, which are connected to each other. It can be understood that the first flat region 110 can be a relatively flat area of ​​the wound cell, and the first bent region 120 can be a relatively curved area of ​​the wound cell.

[0034] Reference Figure 2 and Figure 3 A first boundary position 130 exists between the first straight region 110 and the first bent region 120. It can be understood that the first boundary position 130 can be a straight line or a curve, depending on the actual situation. At the first boundary position 130, the wound cell has a first reinforcing structure 140, which connects the first straight region 110 and the first bent region 120, thereby enhancing the connection strength between them. It can be understood that the first reinforcing structure 140 is located on the outer side of the first electrode 100.

[0035] It should be noted that the material of the first reinforcing structure 140 can be the same as or different from the material of the first electrode 100. For example, the first reinforcing structure 140 can be aluminum foil (high-strength aluminum foil, high-ductility aluminum foil), coated aluminum foil, copper foil, or composite current collector, etc. The specific material of the first reinforcing structure 140 can be determined according to the actual situation.

[0036] In the technical solution of this utility model, the cell structure 10 includes a wound cell. The wound cell includes a first electrode 100 located on the outer layer and a separator 200 and a second electrode 300 stacked with the first electrode 100. The first electrode 100 and the second electrode 300 have opposite polarities. The first electrode 100 located on the outer layer includes a first flat region 110 and a first bent region 120 connected to each other. In the prior art, a porous separator is used in high-silicon batteries to improve the problem of lithium plating at corners. However, the space of the porous separator in the flat region is compressed after formation and hot pressing, while the bent region has reserved space because the porous separator has reserved space. The expansion of the electrode in the bent region is relatively smaller than that in the flat region. Therefore, at the junction of the flat region and the bent region, the end foil is subjected to tension caused by the difference in expansion, that is, the problem of foil breakage is likely to occur at this junction. This design has a first boundary position 130 between the first straight region 110 and the first bending region 120. At the first boundary position 130, the wound cell also has a first reinforcing structure 140. Therefore, even if the first electrode 100 located on the outer layer breaks at the first boundary position 130, the cell can still perform charging and discharging operations because the first reinforcing structure 140 connects the first straight region 110 and the first bending region 120. This design can effectively improve the tensile strength of the cell and improve the problem of lithium plating at the corner. Compared with the solution of increasing the foil thickness to enhance the tensile strength of the foil, this solution can effectively avoid the situation where the energy density of the cell will decrease after the foil thickness is increased, thus ensuring the performance of the cell.

[0037] Reference Figure 2 and Figure 3In some embodiments, the first electrode 100 includes a second flat region 150 connected to the first bending region 120. Along the thickness direction of the wound cell, the second flat region 150 is located on the side of the first bending region 120 opposite to the first flat region 110, as shown in the figure. Figure 2 Orientation, that is, along the vertical direction, the second straight zone 150 is arranged opposite to the first straight zone 110.

[0038] Reference Figure 3 In some embodiments, a second boundary position 160 is provided between the second straight region 150 and the first bending region 120. The second boundary position 160 can be a straight line or a curve. At the second boundary position 160, the wound cell is also provided with a second reinforcing structure 170. The specific structure of the second reinforcing structure 170 can be the same as or different from the first reinforcing structure 140. It should be noted that the second reinforcing structure 170 connects the second straight region 150 and the first bending region 120. In other embodiments, the cell structure 10 may be provided with a third reinforcing structure 180 at a third boundary position 181. In other embodiments, the cell structure 10 may be provided with a fourth reinforcing structure 190 at a fourth boundary position 191. The specific arrangement of the reinforcing structures can be determined according to the actual situation.

[0039] The cell structure 10 of this solution is provided with a second reinforcing structure 170. Therefore, even if the first electrode 100 located on the outer layer breaks at the second junction position 160, the cell can still perform normal charging and discharging operations because the second reinforcing structure 170 connects the second straight area 150 and the first bending area 120. In other words, this solution can effectively improve the tensile strength of the cell and improve the problem of lithium plating at the corner, avoiding the situation where the energy density of the cell will decrease after the foil thickness is increased, thus ensuring the performance of the cell.

[0040] Reference Figure 3 The specific connection configuration of the first reinforcing structure 140 with the first straight region 110 and the first bending region 120 is described below. In some embodiments, along the winding direction of the wound cell, the first reinforcing structure 140 includes a first end 141 facing away from the first bending region 120 and a second end 142 facing away from the first straight region 110, as shown below. Figure 3In terms of orientation, the left end of the first reinforcing structure 140 can be a first end 141, and the right end of the first reinforcing structure 140 can be a second end 142. The first end 141 can be welded to the first straight area 110, and the second end 142 can be welded to the first bending area. It is understood that in some embodiments, the portion of the first reinforcing structure 140 other than the first end 141 and the second end 142 can also be welded to the core body, and the specific welding area of ​​the first reinforcing structure 140 can be determined according to the actual situation. Furthermore, the first reinforcing structure 140 can be laser-welded to the core body. It should be noted that the material of the first reinforcing structure 140 can be a metallic material, and the specific material selection can be determined according to the actual situation. This solution can ensure the connection strength and stability between the first reinforcing structure 140 and the core body, effectively preventing cell failure caused by foil breakage.

[0041] Reference Figure 3 The specific connection position of the second end 142 of the first reinforcing structure 140 is described below. In some embodiments, the first bending region 120 has an inflection point 121, which is located on the side of the first bending region 120 opposite to the first straight region 110. It can be understood that the convexity and concavity of the curve of the first bending region 120 will change at the inflection point 121. The second end 142 is located between the inflection point 121 and the first boundary position 130, and the second end 142 is spaced apart from both the inflection point 121 and the first boundary position 130. In other words, the second end 142 of the first reinforcing structure 140 extends beyond the first boundary position 130 and is connected within the first bending region 120. The first reinforcing structure 140 of this solution can effectively improve the tensile strength of the battery cell and ensure that the battery cell can continue to operate normally.

[0042] Reference Figure 3 The specific connection position of the first end 141 of the first reinforcing structure 140 is described below. In some embodiments, the first end 141 is located on the side of the first boundary position 130 away from the inflection point 121. The first boundary position 130 has a first boundary line 131 parallel to the first straight region 110, as shown below. Figure 3 The first boundary line 131 is dotted. Along the thickness direction perpendicular to the wound cell, the distance from the first end 141 to the boundary line is L, where L satisfies: 1mm ≤ L ≤ 2mm. For example, L can be 1mm, 1.2mm, 1.3mm, 1.5mm, 1.6mm, 1.9mm, or 2mm, etc. The first reinforcing structure 140 of this solution can effectively improve the tensile strength of the cell, ensuring the cell can continue to operate normally.

[0043] Reference Figure 3The specific structure of the first reinforcing structure 140 is described below. In some embodiments, along the winding direction of the wound cell, the extension length of the first reinforcing structure 140 is D, and the thickness of the wound cell is T. The first reinforcing structure 140 satisfies: π×T / 4≤D≤π×1.14T / 4. For example, D can be π×T / 4mm, π×1.1T / 4mm, or π×1.14T / 4mm, etc. In other embodiments, the extension width of the first reinforcing structure 140 can be less than or equal to the height of the wound cell body. The wound cell of this solution adopts the above-mentioned configuration, which can effectively avoid the interference of the first reinforcing structure 140 with the tabs, ensuring that the cell can continue to work normally.

[0044] The thickness setting of the first reinforcing structure 140 is described below. In some embodiments, the thickness of the first reinforcing structure 140 is H, where H satisfies: 10μm ≤ H ≤ 80μm. Exemplarily, H can be 10μm, 15μm, 34μm, 45μm, 58μm, 60μm, 70μm, or 80μm, etc. The first reinforcing structure 140 of this solution adopts the above-mentioned thickness, which can improve the tensile strength of the battery cell and avoid the situation where the overall space occupied by the wound battery cell is too large.

[0045] In some embodiments, along the thickness direction of the wound cell, the first reinforcing structure 140 and the second reinforcing structure 170 are arranged opposite to each other and spaced apart. (Refer to...) Figure 3 In terms of orientation, the first reinforcing structure 140 and the second reinforcing structure 170 are arranged opposite each other in the vertical direction. The reinforcing structure of this scheme adopts the above-mentioned arrangement, which can ensure the uniformity of the strength of the cell structure.

[0046] A second aspect of this utility model provides a battery including the cell structure 10 described in the above embodiment. In this solution, a first boundary position 130 is located between the first straight region 110 and the first bending region 120. At the first boundary position 130, a first reinforcing structure 140 is also provided when the cell is wound. Therefore, even if the first electrode 100 located on the outer layer breaks at the first boundary position 130, the cell can still perform charging and discharging operations because the first reinforcing structure 140 connects the first straight region 110 and the first bending region 120. This solution effectively improves the tensile strength of the cell and mitigates the problem of lithium plating at corners, ensuring cell performance.

[0047] A third aspect of this utility model provides an electrical device, which includes the battery described in the above embodiment. The battery is used to power the electrical device. It is understood that the electrical device can be a mobile phone, tablet computer, laptop computer, battery-powered toy, power tool, or electric vehicle, etc., and the specific application depends on the actual situation. The battery in this solution can ensure the stability and reliability of the electrical device's operation.

[0048] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0049] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or," "and / or," or "and / or" throughout the text implies three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where A and B are simultaneously satisfied. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0050] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the inventive concept of this utility model and the contents of this utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. A cell structure, characterized in that, include: A wound battery cell, the wound battery cell including a first electrode sheet located on the outer layer and a diaphragm and a second electrode sheet stacked on the first electrode sheet, the first electrode sheet and the second electrode sheet having opposite polarities; the first electrode sheet located on the outer layer includes a first straight region and a first bent region connected to each other; The first straight area and the first bent area have a first boundary position. At the first boundary position, the wound cell is further provided with a first reinforcing structure, which connects the first straight area and the first bent area.

2. The cell structure as described in claim 1, characterized in that, The first electrode includes a second flat region connected to the first bending region. Along the thickness direction of the wound cell, the second flat region is located on the side of the first bending region opposite to the first flat region. The second straight area and the first bent area have a second boundary position. At the second boundary position, the wound cell is also provided with a second reinforcing structure, which connects the second straight area and the first bent area.

3. The cell structure as described in claim 1, characterized in that, Along the winding direction of the wound cell, the first reinforcing structure includes a first end away from the first bending region and a second end away from the first straight region. The first end is welded to the first straight region, and the second end is welded to the first bending region. The first reinforcing structure is made of metal.

4. The cell structure as described in claim 3, characterized in that, The first bending area has an inflection point position that is away from the first straight area, and the second end is located between the inflection point position and the first boundary position, and the second end is spaced apart from both the inflection point position and the first boundary position.

5. The cell structure as described in claim 4, characterized in that, The first end is located on the side away from the inflection point of the first boundary position. The first boundary position has a first boundary line parallel to the first straight area. Along the thickness direction perpendicular to the wound cell, the distance from the first end to the boundary line is L, where L satisfies: 1mm≤L≤2mm.

6. The cell structure as described in claim 1, characterized in that, Along the winding direction of the wound cell, the extension length of the first reinforcing structure is D, and the thickness of the wound cell is T, satisfying: π×T / 4≤D≤π×1.14T / 4.

7. The cell structure as described in claim 1, characterized in that, The thickness of the first reinforcing structure is H, where H satisfies: 10μm≤H≤80μm.

8. The cell structure as described in claim 2, characterized in that, Along the thickness direction of the wound cell, the first reinforcing structure and the second reinforcing structure are arranged opposite to each other.

9. A battery, characterized in that, Including the cell structure as described in any one of claims 1-8.

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

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