Battery cell and battery

Abstract

The utility model relates to the field of batteries, and discloses a pole piece and a battery, and the pole piece comprises an insulating adhesive film, a first pole piece, a second pole piece and a diaphragm, the first pole piece and / or the second pole piece comprises a current collector, an active material layer and a limiting structure part; the at least one active material layer comprises a first region and a second region; the thickness of the first area is smaller than that of the second area, and the first area is located at the head and / or the tail of the active material layer in the winding direction; the limiting structure part is located between the active material layer and the current collector; and / or the limiting structure part is connected with the first end part of the first area; the first end portion is one end of the first area away from the second area. The limiting structure part plays a role in protecting the current collector during thinning, so that the current collector is prevented from being damaged, and the safety of the battery is improved.

Description

Technical Field

[0001] This application relates to the field of batteries, and particularly to a battery cell and a battery. Background Art

[0002] The battery cell of a lithium battery includes a positive electrode sheet, a negative electrode sheet, and a separator. The electrode sheet includes a current collector and active material layers located on the upper and lower surfaces of the current collector. Among them, when the electrode sheet is a positive electrode sheet, the active material layer is a positive electrode active material layer, and when the electrode sheet is a negative electrode sheet, the active material layer is a negative electrode active material layer.

[0003] The battery adopts a buried glue technology. After the active material layer is coated on the current collector, part of the active material layer is removed to form a thinning area, and then a glue film layer is attached to the thinning area and the current collector. When removing the active material layer, due to the instability of the equipment and the manufacturing process, it is impossible to ensure that the removal process stops accurately at the junction position between the active material layer and the current collector, which is very likely to damage the current collector and affect the safety performance of the battery cell.

[0004] Therefore, how to solve the above technical problems should be the key concern of those skilled in the art. Utility Model Content

[0005] The purpose of this application is to provide a battery cell and a battery, which can improve the yield rate of the current collector in the electrode sheet and enhance the safety of the battery.

[0006] To solve the above technical problems, this application provides a battery cell, including: an insulating glue film, a first electrode sheet, a second electrode sheet, and a separator wound around, the separator being located between the first electrode sheet and the second electrode sheet; the first electrode sheet and / or the second electrode sheet includes:

[0007] a current collector, an active material layer, and a limiting structure part, the active material layer being located on the first surface and / or the second surface of the current collector;

[0008] At least one layer of the active material layer includes a first region and a second region; the thickness of the first region is less than the thickness of the second region, and the first region is located at the head and / or the tail of the active material layer along the winding direction;

[0009] The limiting structure part is located between the active material layer and the current collector; and / or, the limiting structure part is connected to the first end of the first region; the first end of the first region is the end of the first region far from the second region.

[0010] Optionally, the projection of the first end of the first region on the current collector is located within the projection range of the limiting structure part on the current collector.

[0011] Optionally, the insulating adhesive film covers at least the first region and the limiting structure portion, and does not extend beyond the first region.

[0012] Optionally, the limiting structure portion includes a first protective layer; the first protective layer includes an insulating layer and / or a conductive layer.

[0013] Optionally, the projection of the first end portion of the first protective layer on the current collector is within the range of the projection of the first region on the current collector;

[0014] Wherein, the first end portion of the first protective layer is the end portion of the first protective layer close to the second region.

[0015] Optionally, the length of the overlapping region between the projection of the first region on the current collector and the projection of the first protective layer on the current collector is not greater than 10 mm.

[0016] Optionally, the insulating layer is close to the exposed current collector, and the conductive layer is far from the exposed current collector.

[0017] Optionally, the insulating layer includes a ceramic layer.

[0018] Optionally, it further includes a second protective layer;

[0019] The second protective layer is located on the first surface and / or the second surface of the current collector, and is located on the side of the first region away from the second region; there is a gap between the second protective layer and the first protective layer.

[0020] Optionally, the length of the gap is at least 5 mm, and / or the second protective layer includes an insulating layer and / or a conductive layer.

[0021] Optionally, the limiting structure portion includes an active material portion, and the sum of the thickness of the active material portion and the thickness of the insulating adhesive film is less than the thickness of the second region.

[0022] This application also provides a battery, which includes a tab, a packaging case, and any one of the above-mentioned battery cells. The battery cell is located in the packaging case, the tab is connected to the battery cell, and is partially exposed outside the packaging case.

[0023] A pole piece provided by the present application includes: an insulating adhesive film, a first pole piece, a second pole piece and a separator wound around, wherein the separator is located between the first pole piece and the second pole piece; the first pole piece and / or the second pole piece includes: a current collector, an active material layer and a limiting structure part, and the active material layer is located on the first surface and / or the second surface of the current collector; at least one layer of the active material layer includes a first region and a second region; the thickness of the first region is less than the thickness of the second region, and the first region is located at the head and / or the tail of the active material layer along the winding direction; the limiting structure part is located between the active material layer and the current collector, and the projection of the first end of the first region on the current collector is located within the projection range of the limiting structure part on the current collector; and / or, the limiting structure part is connected to the first end of the first region; the first end of the first region is the end of the first region far from the second region; the insulating adhesive film covers at least the first region and the limiting structure part and does not exceed the first region.

[0024] It can be seen that the battery cell of the present application is a wound battery cell. The first pole piece and / or the second pole piece in the battery cell includes a current collector, an active material layer and a limiting structure part. The active material layer can include a second region and a first region with a reduced thickness. The first region can be located at the head and / or the tail of the active material layer. There is a current collector exposed on the side of the first region far from the second region that is not covered by the active material layer. The limiting structure part is arranged between the active material layer and the current collector. Therefore, when the active material layer is thinned to form the first region, the limiting structure part can play a role in limiting and protecting, avoiding damage to the current collector exposed in the first region. The limiting structure part is connected to the first end of the first region. Therefore, when the active material layer is thinned to form the first region, the limiting structure part can play a role in limiting and protecting, avoiding contact with the current collector exposed in the first region during thinning, thereby avoiding damage to the current collector exposed in the first region. Since the current collector can be protected from damage, the yield rate of the pole piece is improved, and at the same time, the safety of the battery cell can be improved. In addition, the first region can provide a space for accommodating the insulating adhesive film, avoiding the thickness of the insulating adhesive film affecting the overall thickness of the battery cell and reducing the thickness of the battery cell.

[0025] In addition, the present application also provides a battery having the above advantages. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 Schematic cross-section of a battery cell provided by an embodiment of the present application Figure 1 ;

[0028] Figure 2 Schematic cross-section of a battery cell provided by an embodiment of the present application Figure 2 ;

[0029] Figure 3 Schematic cross-section of a pole piece provided by an embodiment of the present application Figure 1 ;

[0030] Figure 4 Schematic cross-section of a pole piece provided by an embodiment of the present application Figure 2 ;

[0031] Figure 5 Schematic cross-section of a pole piece provided by an embodiment of the present application Figure 3 ;

[0032] Figure 6 Schematic cross-section of a pole piece provided by an embodiment of the present application Figure 4 ;

[0033] Figure 7 Schematic cross-section of a pole piece provided by an embodiment of the present application Figure 5 ;

[0034] Figure 8 Schematic cross-section of a pole piece provided by an embodiment of the present application Figure 6 ;

[0035] Figure 9 Schematic cross-section of a pole piece provided by an embodiment of the present application Figure 7 ;

[0036] Figure 10 Top view of the position of a tab on a pole piece provided by an embodiment of the present application;

[0037] Figure 11 is Figure 10 cross-sectional schematic diagram;

[0038] Figure 12 Another top view of the position of a tab on a pole piece provided by an embodiment of the present application;

[0039] Figure 13 is Figure 12 cross-sectional schematic diagram;

[0040] In the figure, 10 is an insulating adhesive film, 20 is a first electrode tab, 30 is a second electrode tab, 40 is a separator, 50 is an electrode ear, 1 is a current collector, 2 is an active material layer, 3 is a first protective layer, 4 is a second protective layer, 21 is a first region, 22 is a second region, 211 is a first end of the first region, 212 is a second end of the first region, 31 is an insulating layer, 32 is a conductive layer, 311 is a first end of the first protective layer, and 312 is a second end of the first protective layer. Detailed implementation mode

[0041] In order to enable those skilled in the art to better understand the solution of this application, the following further details this application in conjunction with the accompanying drawings and specific implementation modes. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope protected by this application.

[0042] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0043] As described in the background art section, currently when manufacturing a wound battery cell, when removing the active material layer on the electrode tab, due to the instability of the equipment and process, it is impossible to ensure that the removal process stops accurately at the junction position between the active material layer and the current collector, which is very likely to damage the current collector and affect the safety performance of the battery cell.

[0044] In view of this, this application provides a battery cell. Please refer to Figures 1 to 9 , including: an insulating adhesive film 10, a first electrode tab 20, a second electrode tab 30 and a separator 40 wound around, and the separator 40 is located between the first electrode tab 20 and the second electrode tab 30; the first electrode tab 20 and / or the second electrode tab 30 includes:

[0045] a current collector 1, an active material layer 2 and a limiting structure part, and the active material layer 2 is located on the first surface and / or the second surface of the current collector 1;

[0046] at least one active material layer 2 includes a first region 21 and a second region 22; the thickness of the first region 21 is less than the thickness of the second region 22, and the first region 21 is located at the head N and / or the tail M of the active material layer 2 along the winding direction;

[0047] The limiting structure part is located between the active material layer 2 and the current collector 1; and / or, the limiting structure part is connected to the first end 211 of the first region 21; the first end 211 of the first region 21 is the end of the first region 21 far from the second region 22.

[0048] The insulating adhesive film 10 is also an insulating adhesive paper. The purpose of the insulating adhesive film 10 not exceeding the first region 21 is to utilize the space provided by the first region 21 to avoid the increase in the thickness of the battery cell caused by the thickness of the insulating adhesive film 10.

[0049] One of the first electrode sheet 20 and the second electrode sheet 30 is a positive electrode sheet, and the other is a negative electrode sheet. For the current collector 1 and the active material layer 2 used for the positive electrode sheet, and the current collector 1 and the active material layer 2 used for the negative electrode sheet, reference can be made to the related art, and details are not elaborated here.

[0050] The first electrode sheet 20, the second electrode sheet 30, and the separator 40 disposed between the first electrode sheet 20 and the second electrode sheet 30 are wound in one direction to form a battery cell. The separator 40 has an insulating function.

[0051] The first surface and the second surface of the current collector 1 are two opposite surfaces. Before winding, the first surface and the second surface can be the upper surface and the lower surface of the current collector 1 respectively.

[0052] When the second electrode sheets 30 are distributed on both sides of the first electrode sheet 20, the active material layers 2 are distributed on both the first surface and the second surface of the current collector 1 in the first electrode sheet 20. When the second electrode sheets 30 are distributed on only one side of the first electrode sheet 20, the active material layer 2 is distributed on the surface of the current collector 1 close to the side where the second electrode sheets 30 are distributed.

[0053] When the first electrode sheets 20 are distributed on both sides of the second electrode sheet 30, the active material layers 2 are distributed on both the first surface and the second surface of the current collector 1 in the second electrode sheet 30. When the first electrode sheets 20 are distributed on only one side of the second electrode sheet 30, the active material layer 2 is distributed on the surface of the current collector 1 close to the side where the first electrode sheets 20 are distributed.

[0054] On the electrode sheets located at the innermost and outermost layers of the battery cell, the active material layer 2 is distributed on one side surface of the current collector 1, as Figure 1 and Figure 2 shown.

[0055] The first region 21 on the active material layer 2 is a thinned region, and the second region 22 is an unthinned region. The first region 21 can be only located at the head N of the active material layer 2, or only located at the tail M of the active material layer 2, or located at both the head N and the tail M of the active material layer 2 at the same time.

[0056] There are no specific limitations on the head N and the tail M of the active material layer 2. After the active material layer 2 is coated on the current collector 1 and before winding, at both ends in the length direction of the active material layer 2, one end is regarded as the head N and the other end is regarded as the tail M.

[0057] The first region 21 and the second region 22 on the active material layer 2 are connected. The first end 211 of the first region 21 is the end far from the second region 22, and the second end 212 of the first region 21 is the end connected to the first region 21.

[0058] In this embodiment, there are three settings for the position of the limiting structure part. First, the limiting structure part is only located between the active material layer 2 and the current collector 1, and the projection of the first end 211 of the first region 21 on the current collector 1 is within the projection range of the limiting structure part on the current collector 1. Second, the limiting structure part is connected to the first end 211 of the first region 21, and there is no limiting structure between the active material layer 2 and the current collector 1. Third, there are limiting structures distributed between the active material layer 2 and the current collector 1, and the first end 211 of the first region 21 is connected to a limiting structure.

[0059] The battery cell in this embodiment is a wound battery cell. The first electrode sheet 20 and / or the second electrode sheet 30 in the battery cell include a current collector 1, an active material layer 2, and a limiting structure part. The active material layer 2 may include a second region 22 and a first region 21 with a reduced thickness. The first region 21 may be located at the head N and / or the tail M of the active material layer 2. There is a current collector 1 on the side of the first region 21 far from the second region 22 that is not covered by the active material layer 2. The limiting structure part is arranged between the active material layer 2 and the current collector 1. Therefore, when the active material layer 2 is thinned to form the first region 21, the limiting structure part can play a role in limiting and protecting, avoiding damage to the current collector 1 exposed in the first region 21. The limiting structure part is connected to the first end 211 of the first region 21. Therefore, when the active material layer 2 is thinned to form the first region 21, the limiting structure part can play a role in limiting and protecting, avoiding contact with the current collector 1 exposed in the first region 21 during thinning, thereby avoiding damage to the current collector 1 exposed in the first region 21. Since the current collector 1 can be protected from damage, the yield rate of the electrode sheet is improved, and at the same time, the safety of the battery cell can be improved. In addition, the first region 21 can provide a space for accommodating the insulating adhesive film 10, avoiding the thickness of the insulating adhesive film 10 affecting the overall thickness of the battery cell and reducing the thickness of the battery cell.

[0060] On the basis of the above embodiment, in an embodiment of the present application, the projection of the first end 211 of the first region 21 on the current collector 1 is within the projection range of the limiting structure part on the current collector 1. The limiting structure part extends beyond the first region 21, and the limiting structure part can play a better role in protecting the edge of the current collector 1 during thinning.

[0061] Based on any of the above embodiments, in an embodiment of the present application, the insulating adhesive film 10 covers at least the first region 21 and the limiting structure portion, and does not extend beyond the first region 21. The first region 21 can provide sufficient placement space for the insulating adhesive film 10, minimizing the thickness of the battery cell to the greatest extent.

[0062] Based on the above embodiments, in an embodiment of the present application, please refer to Figures 3 to 5 , the limiting structure portion includes a first protective layer 3; the first protective layer 3 includes an insulating layer 31 and / or a conductive layer 32. At this time, the first protective layer 3 is located between the active material layer 2 and the current collector 1, and the projection of the first end portion 211 of the first region 21 on the current collector 1 is within the projection range of the first protective layer 3 on the current collector 1.

[0063] There are three types of the first protective layer 3. The first type is that the first protective layer 3 only includes the insulating layer 31. The second type is that the first protective layer 3 only includes the conductive layer 32. The third type is that the first protective layer 3 includes the insulating layer 31 and the conductive layer 32.

[0064] When the first protective layer 3 includes the insulating layer 31 and the conductive layer 32, the insulating layer 31 and the conductive layer 32 are on the same horizontal plane and are both on the surface of the current collector 1.

[0065] The insulating layer 31 includes, but is not limited to, a ceramic layer. Ceramics have the characteristics of high hardness and high temperature resistance, which can play a better protective role for the current collector 1 in the thinning process of the first region 21, and at the same time ensure that the active material layer 2 is effectively washed away.

[0066] The conductive layer 32 can be a film layer formed of metal or other conductive materials.

[0067] When the insulating layer 31 is included in the first protective layer 3, the insulating layer 31 may affect the conductivity and activity of the corresponding active material layer 2. In order to minimize the influence of the insulating layer 31 on the active material layer 2. In a feasible embodiment, the length of the overlapping area between the projection of the first region 21 on the current collector 1 and the projection of the first protective layer 3 on the current collector 1 is not greater than 10 mm.

[0068] Next, the setting positions of the first protective layer 3 will be introduced separately according to different situations of the first protective layer 3.

[0069] Example 1

[0070] Such as Figure 3As shown, when the first protective layer 3 is any one of the above three types, the projection of the first end of the first protective layer 3 on the current collector 1 is located within the range of the projection of the first region 21 on the current collector 1; wherein, the first end 311 of the first protective layer 3 is an end of the first protective layer 3 close to the second region 22.

[0071] The first end 311 of the first protective layer 3 is located between the active material layer 2 and the current collector 1, and the second end 312 of the first protective layer 3 exceeds the first region 21 of the active material layer 2. The length of the first protective layer 3 exceeding the first region 21 is B, and B is greater than zero. The first end of the first protective layer 3 is located between the first region 21 and the current collector 1, which can reduce the length setting of the first protective layer 3, save the amount of the first protective layer 3, and reduce the cost.

[0072] The insulating film 10 may cover the first region 21 , the region of the first protective layer 3 not covered by the first region 21 , and the exposed current collector 1 , or the insulating film 10 may cover the first region 21 and the region of the first protective layer 3 not covered by the first region 21 .

[0073] Example 2

[0074] like Figure 4 As shown, when the first protective layer 3 only includes the conductive layer 32, the projection of the active material layer 2 on the current collector 1 can be entirely within the projection of the first protective layer 3 on the current collector 1. The length of the conductive layer 32 beyond the first region 21 is B, and B is greater than zero.

[0075] At this time, the first protective layer 3 may have the following functions: first, when the active material layer 2 is thinned to form the first region 21, it plays a protective and buffering role to protect the current collector 1 from damage; second, it improves the safety performance of the battery cell during acupuncture; third, the first protective layer 3 can be conductive as a whole and will not block the electronic conduction performance between the active material layer 2 and the current collector 1.

[0076] The insulating film 10 may cover the first region 21 , the region of the first protective layer 3 not covered by the first region 21 , and the exposed current collector 1 , or the insulating film 10 may cover the first region 21 and the region of the first protective layer 3 not covered by the first region 21 .

[0077] It should be pointed out that when the first protective layer 3 only includes the insulating layer 31 , the projection of the active material layer 2 on the current collector 1 cannot be completely located within the range of the projection of the first protective layer 3 on the current collector 1 , that is, there needs to be a conductive part between the active material layer 2 and the current collector 1 .

[0078] Example 3

[0079] like Figure 5As shown, when the first protective layer 3 includes an insulating layer 31 and a conductive layer 32 , the insulating layer 31 may be close to the exposed current collector 1 , and the conductive layer 32 may be far away from the exposed current collector 1 .

[0080] When the paste is coated on the current collector 1 to form the active material layer 2 , a blank area will be left at the end of the current collector 1 . The blank area does not have the active material layer 2 , and the current collector 1 in the blank area is the exposed current collector 1 .

[0081] The insulating layer 31 and the conductive layer 32 may be in contact with each other or have a certain gap in between, which is not limited in this embodiment.

[0082] The end of the insulating layer 31 away from the conductive layer 32 extends out of the region where the active material layer 2 and the current collector 1 are stacked. The length of the insulating layer 31 beyond the first region 21 is B, which is greater than zero. When the active material layer 2 is removed to form the first region 21, the current collector 1 is protected from damage. The projection of the end of the insulating layer 31 close to the conductive layer 32 on the current collector 1 is within the projection range of the first region 21 on the current collector 1, reducing the influence of the insulating layer 31 on the activity and conductivity of the first region 21. The length A of the overlapping area between the projection of the first region 21 on the current collector 1 and the projection of the insulating layer 31 on the current collector 1 may be no greater than 10 mm to reduce the influence of the insulating layer 31 on the active material layer 2.

[0083] Except for the region where the insulating layer 31 is located, the other regions between the active material layer 2 and the current collector 1 may all be provided with the conductive layer 32 , or the conductive layer 32 may be provided in a partial region.

[0084] The conductive layer 32 located between the active material layer 2 and the current collector 1 can improve the safety performance of the battery cell during needle puncture on the one hand, and can also conduct electricity on the other hand without affecting the electronic conduction between the active material layer 2 and the current collector 1.

[0085] The insulating film 10 may cover the first region 21 , the region of the first protective layer 3 not covered by the first region 21 , and the exposed current collector 1 , or the insulating film 10 may cover the first region 21 and the region of the first protective layer 3 not covered by the first region 21 .

[0086] Please refer to Figure 6 , based on the above implementation, in one embodiment of the present application, the battery cell may further include a second protective layer 4;

[0087] The second protective layer 4 is located on the first surface and / or the second surface of the current collector 1 , and is located on a side of the first region 21 away from the second region 22 ; a gap is distributed between the second protective layer 4 and the first protective layer 3 .

[0088] The second protective layer 4 is located on the surface of the exposed current collector 1. The second protective layer 4 has a protective effect on the exposed current collector 1, which can improve the safety of the head N and / or the tail M of the battery cell.

[0089] The battery cell has a wound structure. The gap between the second protective layer 4 and the first protective layer 3 corresponds to the arc region of the battery cell, avoiding excessive pressure on the electrode sheet during winding and reducing the risk of electrode sheet breakage.

[0090] The insulating adhesive film 10 can cover the first region 21 and the region of the first protective layer 3 not covered by the first region 21. There is no insulating adhesive film 10 layer at the gap.

[0091] As an implementable manner, the length C of the gap is at least 5 mm. If the length C of the gap is less than 5 mm, the distance between the second protective layer 4 and the first protective layer 3 is relatively close. When coating the second protective layer 4, the second protective layer 4 is also likely to contact the insulating layer 31, which is not convenient for manufacturing the second protective layer 4. And during winding, the second protective layer 4 is likely to be located in the arc region, resulting in relatively large stress in the arc region and further causing electrode sheet breakage.

[0092] As an implementable manner, the second protective layer 4 includes an insulating layer and / or a conductive layer. The insulating layer can be a ceramic layer or a film layer formed of other insulating materials, which is not specifically limited in this embodiment. The conductive layer can be a metal film layer or a film layer formed of other conductive materials, which is not specifically limited in this embodiment.

[0093] When the second protective layer 4 includes an insulating layer and a conductive layer, both the insulating layer and the conductive layer are located on the surface of the current collector 1.

[0094] To simplify the manufacturing process, the material of the first protective layer 3 can be the same as that of the second protective layer 4.

[0095] Please refer to Figures 7 to 9 , on the basis of the above embodiments, in an embodiment of the present application, the limiting structure portion includes an active material portion 5. The sum of the thickness of the active material portion 5 and the thickness of the insulating adhesive film 10 is less than the thickness of the second region 22. At this time, the active material portion 5 is connected to the first end portion 211 of the first region 21.

[0096] The material of the active material portion 5 can be the same as that of the active material layer 2.

[0097] Before winding the electrode plate (the first electrode plate 20 and / or the second electrode plate 30) including the active material part 5, the thickness of the active material part 5 is not greater than the thickness of the second region 22. When the battery cell is subsequently manufactured, the active material part 5 collapses under pressure, and thus the thickness is less than the thickness of the second region 22. At the same time, the sum of the thickness of the collapsed active material part 5 and the thickness of the insulating adhesive film 10 is less than the thickness of the second region 22, so as to provide space for the insulating adhesive film 10 together with the first region 21 and reduce the thickness of the battery cell.

[0098] The insulating adhesive film 10 can cover the first region 21, the active material part 5, and the exposed current collector 1.

[0099] Figures 7 to 9 Before winding the first electrode plate 20 and / or the second electrode plate 30, the active material part 5 is not subjected to an external force, that is, it is a schematic diagram when it has not collapsed. At this time, the thickness W2 of the second region 22 ≥ the thickness W3 of the active material part 5 when it has not collapsed > the thickness W1 of the first region 21, the width W4 of the active material part 5 when it has not collapsed is greater than zero, and can be less than or equal to 5 mm. If the width of the active material part 5 when it has not collapsed exceeds 5 mm, it will cause waste.

[0100] The width of the active material part 5 when it has not collapsed must be greater than zero. The main purpose is to reserve space to act as a barrier when thinning to form the first region 21 and avoid damaging the current collector 1 during the thinning process.

[0101] At the same time, the sum of the thickness W3 of the active material part 5 when it has not collapsed and the thickness of the insulating adhesive film 10 is less than or equal to the thickness W2 of the second region 22. After the active material part 5 collapses, the sum of the thickness W3 of the active material part 5 when it has not collapsed and the thickness of the insulating adhesive film 10 is less than the thickness W2 of the second region 22, so as to provide space for the insulating adhesive film 10 and reduce the thickness of the battery cell.

[0102] The present application also provides a battery, which includes a tab 50, a packaging case, and the battery cell of any one of the above embodiments. The battery cell is located in the packaging case, and the tab 50 is connected to the battery cell and partially exposed outside the packaging case.

[0103] The tab 50 includes a positive tab and a negative tab. The positive tab is connected to the current collector 1 of the positive electrode plate, and the negative tab is connected to the current collector 1 of the negative electrode plate.

[0104] In this embodiment, the connection position of the tab 50 and the current collector 1 is not limited and can be determined according to the situation.

[0105] As an implementable manner, as Figure 10 and Figure 11 shown, there can be a blank area in the middle of the current collector 1 for placing the tab 50 and connecting with the tab 50.

[0106] As another implementable embodiment, as Figure 12 and Figure 13 shown, a blank area may exist at the end of the current collector 1 for placing and connecting with the tab 50.

[0107] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0108] The above has introduced the battery cell and battery provided by this application in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of this application. The description of the above embodiments is only used to help understand the solution and core idea of this application. It should be noted that for those of ordinary skill in the art, without departing from the principle of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A battery cell, characterized in that: include: An insulating film, a first pole piece, a second pole piece and a diaphragm which are wound together, wherein the diaphragm is located between the first pole piece and the second pole piece; The first pole piece and / or the second pole piece comprises: A current collector, an active material layer and a limiting structure, wherein the active material layer is located on the first surface and / or the second surface of the current collector; At least one layer of the active material layer includes a first region and a second region; the thickness of the first region is less than the thickness of the second region, and the first region is located at the head and / or tail of the active material layer along the winding direction; The limiting structure is located between the active material layer and the current collector; and / or the limiting structure is connected to a first end of the first region; the first end of the first region is an end of the first region away from the second region.

2. The battery cell according to claim 1, characterized in that: The projection of the first end of the first region on the current collector is located within the projection range of the limiting structure on the current collector.

3. The battery cell according to claim 1, characterized in that: The insulating adhesive film at least covers the first area and the limiting structure portion and does not exceed the first area.

4. The battery cell according to claim 1, characterized in that: The limiting structure includes a first protective layer; the first protective layer includes an insulating layer and / or a conductive layer.

5. The battery cell according to claim 4, characterized in that: The projection of the first end of the first protective layer on the current collector is located within the range of the projection of the first region on the current collector; The first end portion of the first protective layer is an end of the first protective layer close to the second region.

6. The battery cell according to claim 4, characterized in that: The length of the overlapping area between the projection of the first region on the current collector and the projection of the first protective layer on the current collector is not greater than 10 mm.

7. The battery cell according to claim 4, characterized in that: The insulating layer is close to the exposed current collector, and the conductive layer is far away from the exposed current collector.

8. The battery cell according to claim 4, characterized in that: The insulating layer includes a ceramic layer.

9. The battery cell according to claim 4, characterized in that: Also including a second protective layer; The second protective layer is located on the first surface and / or the second surface of the current collector and is located on a side of the first region away from the second region; a gap is distributed between the second protective layer and the first protective layer.

10. The battery cell according to claim 9, characterized in that: The length of the gap is at least 5 mm; and / or the second protective layer includes an insulating layer and / or a conductive layer.

11. The battery cell according to claim 1, characterized in that: The limiting structure portion includes an active material portion, and a sum of a thickness of the active material portion and a thickness of the insulating adhesive film is smaller than a thickness of the second region.

12. A battery, characterized in that: The battery comprises a tab, a packaging shell and a battery cell as claimed in any one of claims 1 to 11, wherein the battery cell is located in the packaging shell, and the tab is connected to the battery cell and partially exposed from the packaging shell.

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