Battery cell and battery

Abstract

The utility model provides a battery cell and a battery, and relates to the technical field of batteries, the battery cell comprises a first pole piece, a diaphragm and a second pole piece which are sequentially stacked and wound, and the polarity of the first pole piece is opposite to that of the second pole piece; the first pole piece comprises a first current collector and a first active layer coated on the first current collector, the first pole piece comprises a winding starting section positioned on the inner side, and the first current collector comprises a blank current collector which is not coated with the first active layer at the winding starting section; the battery cell further comprises fixing glue, the fixing glue is fixed to the end face of the tab end of the battery cell and the flat and straight faces on the two sides of the battery cell in an adhesive mode, and on the flat and straight faces, the projection of the end, away from the first active layer, of the blank current collector is located in the projection of the fixing glue. According to the battery cell, the fixing glue can prevent internal structural parts from moving, so that even if a blank current collector is broken, the problem of short circuit caused by breakage of the current collector can be avoided, and the electrical property of the battery is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery core and a battery. Background Art

[0002] With the development of social economy and science and technology, batteries are used more and more widely in electronic devices, and at the same time, electronic devices have higher and higher requirements for the fast charging performance of batteries.

[0003] In order to increase the energy density, some current battery models use thinner copper foil as the current collector for the electrode of the battery cell. However, this will greatly reduce the tensile strength of the electrode and increase the risk of the current collector breaking, which can easily lead to battery safety hazards. Utility Model Content

[0004] In view of the above problems, the utility model provides a battery cell and a battery, which can eliminate the potential safety hazard caused by the breakage of the current collector and ensure the electrical performance of the battery.

[0005] The utility model provides a battery cell, comprising a first pole piece, a diaphragm and a second pole piece which are sequentially stacked and wound, wherein the first pole piece and the second pole piece have opposite polarities; the first pole piece comprises a first current collector and a first active layer coated on the first current collector, the first pole piece comprises a winding starting section located on the inner side, and the first current collector comprises a blank current collector which is not coated with the first active layer at the winding starting section; the battery cell also comprises a fixing glue, wherein the fixing glue is adhesively fixed to the end face of the pole lug of the battery cell and the flat surfaces on both sides of the battery cell, and on the flat surfaces, the projection of the end of the blank current collector away from the first active layer is located within the projection of the fixing glue.

[0006] According to the battery cell of the utility model embodiment, the fixing glue is at least bonded and fixed to the end face of the pole ear end of the battery cell and the flat surfaces on both sides of the battery cell along the thickness direction, and the projection surface of the blank current collector away from the first active layer is located within the projection of the fixing glue. In this way, the fixing glue can, on the one hand, make the components of the battery cell in the rubber-coated area tightly combined, improve the constraint on the battery cell, and make the various circles of the battery cell better gather to the inner circle to prevent the internal structural parts from moving. On the other hand, even if the blank current collector is broken, it can also slow down or even eliminate the movement of the inner circle structure of the battery cell to a certain extent, thereby preventing the battery from short-circuiting, eliminating the potential safety hazards of the battery, and improving the electrical performance of the battery.

[0007] In some embodiments, the fixing glue is within the coverage range of the blank current collector in the first direction.

[0008] In some embodiments, the width of the blank current collector along the first direction is A, the width of the fixing glue along the first direction is B, and A and B satisfy: 0.1≤B / A≤3.

[0009] In some embodiments, the width of the blank current collector along the first direction is A; the width of the battery cell along the first direction is C, and A and C satisfy: 0.1≤A / C≤0.99.

[0010] In some embodiments, the first current collector includes a folding paste segment having the first active layer coated on one surface at the winding starting segment, the folding paste segment being adjacent to the blank current collector, wherein the width T of the folding paste segment in the first direction ranges from 0mm<T≤5mm.

[0011] In some embodiments, the width of the blank current collector along the first direction is A; the diaphragm includes an extension portion extending beyond the blank current collector along the first direction at the starting section of the winding, the width of the extension portion in the first direction is D, and A and D satisfy: 0.1≤D / A≤3; and / or, at least part of the diaphragm is Z-folded at the starting section of the winding along the first direction beyond the first pole piece to form a folded portion, and the folded portion overlaps with the projection of the blank current collector on the flat surface; the width of the folded portion along the first direction is W, and W and A satisfy: 0.03≤W / A≤1.

[0012] In some embodiments, on the flat surface, the projection of the folded portion is located within the projection of the fixing glue, and the folded portion has a first endpoint close to the winding starting section of the first pole piece in the first direction, and the first endpoint is spaced from the fixing glue in the first direction by D1, and D1 and A satisfy: 0.03≤D1 / A≤2.

[0013] In some embodiments, the battery cell includes: the battery cell also includes a plurality of pole ears extending from the end surface of the pole ears, and each of the pole ears is provided with an insulating rubber layer on both sides along the thickness direction; the plurality of pole ears are arranged at intervals along the first direction, and an avoidance gap is jointly defined between two adjacent pole ears close to the starting section of the winding, and the fixing glue is in the avoidance gap.

[0014] In some embodiments, at least one second pole ear is provided on the second pole sheet, and along the thickness direction of the battery cell, two second avoidance grooves are formed on the first pole sheet arranged opposite to each of the second pole ears, and a second insulating rubber layer is provided in each of the second avoidance grooves, wherein the depth of each of the second avoidance grooves is not less than the sum of the thickness of the insulating rubber layer and the thickness of the fixing glue; and / or, along the thickness direction of the battery cell, two first avoidance grooves are formed on the second pole sheet arranged opposite to each of the first pole ears, and a first insulating rubber layer is provided in each of the first avoidance grooves, wherein the depth of each of the first avoidance grooves is not less than the thickness of the insulating rubber layer.

[0015] In some embodiments, the first active layer includes graphite, and a plurality of recesses are provided on the surface of the first active layer, wherein the plurality of recesses are arranged at intervals along the length direction of the first pole piece, and a depth of the recesses in the thickness direction of the battery cell is h. The ratio of the tensile strength of the first current collector in the second direction to the tensile strength in the first direction is e, and e, h and the graphite orientation ratio OI satisfy: 0.01≤e*h / OI≤25.

[0016] The second aspect of the utility model further provides a battery, comprising: a shell component, the shell component defines a receiving cavity; the battery cell described in the first aspect of the utility model, the battery cell is arranged in the receiving cavity.

[0017] The battery of the utility model can improve the safety of the battery and the electrical performance of the battery by arranging the above-mentioned battery core. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the structure of the battery cell of some embodiments of the utility model;

[0020] Figure 2 It is a cross-sectional view of a battery cell of some embodiments of the utility model;

[0021] Figure 3 It is a schematic diagram of the inner circle structure of the battery cell of some embodiments of the utility model;

[0022] Figure 4 A schematic diagram of the distribution of tabs of a battery cell in some embodiments of the utility model;

[0023] Figure 5 It is a schematic diagram of the structure of the first pole piece of some embodiments of the utility model;

[0024] Figure 6 It is a schematic structural diagram of the first active layer of some embodiments of the utility model.

[0025] Description of reference numerals:

[0026] 100-battery cells;

[0027] 1-first pole piece; 11-first current collector; 12-first active layer; 12a-first side active layer; 12b-second side active layer; 121-recess; 13-bend section; 14-paste folding section; 15-blank current collector;

[0028] 2-diaphragm; 21-folded portion; 22-extension portion;

[0029] 3-second pole piece; 31-second current collector; 32-second active layer;

[0030] 4-Fixing glue;

[0031] 5-insulating rubber layer; 5a-first insulating rubber layer; 5b-second insulating rubber layer;

[0032] 6-first avoidance groove; 7-second avoidance groove; 8-second fixing glue;

[0033] 10 - battery cell body; 101 - first pole lug; 102 - second pole lug; 103 - end surface of the pole lug; 104 - flat surface. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned purposes, features and advantages of the embodiments of the utility model more obvious and easy to understand, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model.

[0035] With the development of social economy and science and technology, batteries are increasingly used in electronic devices, and electronic devices have higher and higher requirements for the fast charging performance of batteries. At present, in order to improve the energy density, some models of batteries use thinner copper foil as the current collector for the pole piece of the battery cell, but this will greatly reduce the tensile strength of the pole piece and greatly increase the risk of the current collector breaking, which can easily lead to battery safety hazards.

[0036] In view of this, the utility model provides a battery cell and a battery, wherein a fixing glue is bonded and fixed to at least the end face of the battery cell's pole ear end and the flat surfaces on both sides of the battery cell along the thickness direction, and the flat surface is used as the projection surface, and the projection of the end of the blank current collector away from the first active layer is located within the projection of the fixing glue. In this way, the fixing glue can, on the one hand, tightly combine the components of the battery cell in the rubber-coated area, improve the constraints on the battery cell, and make the various circles of the battery cell better gather toward the inner circle to prevent the internal structural parts from moving. On the other hand, even if the blank current collector is broken, it can also slow down or even eliminate the movement of the inner circle structure of the battery cell to a certain extent, thereby preventing the battery from short-circuiting, eliminating battery safety hazards, and improving the battery's electrical performance.

[0037] Combine the following Figure 1-Figure 6 The battery cell 100 according to the first embodiment of the utility model is described.

[0038] Combination Figure 2 and Figure 3 The battery cell 100 of this embodiment can be used in a battery. The battery cell 100 may include a first pole piece 1, a separator 2, and a second pole piece 3. The polarities of the first pole piece 1 and the second pole piece 3 are opposite. For example, the first pole piece 1 is preferably a negative pole piece, and the first pole piece 1 includes a first active layer 12 and a first current collector 11, and the first active layer 12 is applied to the opposite side surfaces of the first current collector 11. The second pole piece 3 is preferably a positive pole piece, and the second pole piece 3 may include a second current collector 31 and a second active layer 32, and the second active layer 32 may be applied to the opposite side surfaces of the second current collector 31. The first pole piece 1, the separator 2, and the second pole piece 3 are sequentially stacked and wound, so that the battery cell 100 is formed into a wound battery cell 100.

[0039] The wound battery cell 100 has multiple turns that are nested inside and outside and connected in sequence, that is, the wound battery cell 100 is a spiral structure. The first pole piece 1 includes a winding start section located on the inner side, where the winding start section refers to the first fold of the inner circle of the battery cell 100. It can be understood that in the winding process, the winding needle is in the winding start section, and the stacked structure composed of the second pole piece 3, the diaphragm 2 and the first pole piece 1 is wound around the winding needle, and finally the battery cell 100 of this embodiment is formed.

[0040] The first current collector 11 includes a blank current collector 15 that exceeds the first active layer 12 at the start of winding. The blank current collector 15 here refers to the area of ​​the first current collector 11 that is not coated with the first active layer 12. Accordingly, the area on the first current collector 11 where the first active layer 12 is provided is the paste coating area of ​​the first current collector 11, and the blank current collector 15 can play a role in fixing the first pole piece 1 and the winding needle during the winding process.

[0041] The battery cell 100 comprises a plurality of surfaces after winding, including two relatively large flat surfaces, Figure 1In addition, the end surface 103 of the pole ear extending from the pole ear and the bottom surface 103 of the pole ear end surface are arranged opposite to each other, wherein the pole ear end surface 103 and the bottom surface are arranged along the second direction (such as Figure 1 and Figure 4 The Y direction shown in FIG. 1 is arranged on the upper and lower sides of the flat surface 104.

[0042] The battery cell 100 may further include a fixing glue 4, which is bonded and fixed to the end face 103 of the tab end of the battery cell 100 and the flat surfaces 104 on both sides of the battery cell 100 along the thickness direction (i.e., the flat area of ​​the outermost ring surface of the battery cell 100). In this way, the fixing glue 4 can make the components of the battery cell 100 in the rubber-coated area tightly combined, improve the constraint on the battery cell 100, make the circles of the battery cell 100 better gather to the inner circle, prevent the internal structural parts from moving, and improve the structural stability of the battery cell 100.

[0043] Optionally, refer to Figure 1 In order to improve the uniformity of the convergence force at both ends of the battery cell 100 along the second direction, a second fixing glue 8 is also provided on the bottom surface of the other end of the battery cell 100 along the second direction, and the second fixing glue 8 is bonded and fixed to the end surface of the battery cell 100 opposite to the pole ear end and the flat surfaces 104 on both sides of the battery cell 100 along the thickness direction. There can be multiple second fixing glues 8, and the multiple second fixing glues 8 are arranged at intervals along the first direction.

[0044] In addition, based on the demand for improving the energy density of the battery cell 100, the size of the blank current collector 15 of the first pole piece 1 is getting smaller and smaller to avoid the thickness loss caused by the overlap of the blank current collector 15 and the pole ear. The blank current collector 15 is the spacing area between two adjacent paste areas (each paste area corresponds to the first active layer 12 of the first pole piece 1) in the processing technology of the first pole piece 1. Due to the narrowing of the size of the blank current collector 15, when coating and rolling on the uncut first current collector 11, the gap between the pastes becomes smaller and smaller, and there is not enough space to release the stress caused by the thickness difference between the paste area and the blank current collector 15. At this time, it is easy to cause the paste area of ​​the first pole piece 1 to break at the junction with the empty foil. This fracture process may occur during the production process of the battery cell 100, or during the charging and discharging process of the finished battery, as well as after transportation jitter and use jitter.

[0045] To avoid the above problems, in this embodiment, the flat surface of the battery cell is used as the projection surface, and the projection of the end of the blank current collector 15 away from the first active layer 12 is located within the projection of the fixing glue 4. In other words, the fixing glue 4 and the blank current collector 15 are aligned in the first direction (eg Figure 1 and Figure 4There is an overlap area in the X direction shown in ), optionally, the fixing glue 4 and the blank current collector 15 can partially overlap or completely overlap in the first direction, and the first direction can be the width direction of the battery cell 100. In this way, the fixing glue 4 clamps the sharp corner of the head of the first current collector 11 to prevent the sharp corner from being misaligned due to factors such as vibration. In addition, the fixing glue 4 can be bonded to the side of the blank current collector 15 of the first current collector 11, thereby playing a certain fixing role on the blank current collector 15. Even if the blank current collector 15 is broken, it can slow down or even eliminate the movement of the inner ring structure of the battery cell 100 to a certain extent, thereby preventing the battery from having a short circuit problem and ensuring the battery's electrical performance.

[0046] According to the battery cell 100 of the utility model embodiment, the fixing glue 4 is at least bonded and fixed to the end face 103 of the tab end of the battery cell 100 and the flat surfaces 104 on both sides of the battery cell 100 along the thickness direction, and the flat surface 104 is used as the projection surface, and the projection of the end of the blank current collector 15 104 away from the first active layer 12 is located within the projection of the fixing glue 4. In this way, the fixing glue 4 can, on the one hand, make the components of the battery cell 100 in the rubber-coated area tightly combined, improve the constraint on the battery cell 100, and make the various circles of the battery cell 100 better gather to the inner circle to prevent the internal structural parts from moving. On the other hand, even if the blank current collector 15 is broken, it can slow down or even eliminate the movement of the inner circle structure of the battery cell 100 to a certain extent, thereby preventing the battery from short-circuiting, eliminating the potential safety hazards of the battery, and improving the electrical performance of the battery.

[0047] In some embodiments, the fixing glue 4 is within the coverage of the blank current collector 15 in the first direction. In other words, in this embodiment, the fixing glue 4 and the blank current collector 15 completely overlap in the first direction, and the coverage area of ​​the fixing glue 4 in the first direction is less than or equal to the coverage area of ​​the blank current collector 15 in the first direction. In this way, it is ensured that each area of ​​the fixing glue 4 in the first direction can apply pressure to the blank current collector 15 to increase the pressing area of ​​the fixing glue 4 and the blank current collector 15, and reduce the possibility of misalignment of the fixing glue 4 and the blank current collector 15. In this way, in the case of a break in the blank current collector 15, it can better prevent the inner ring structure of the battery cell 100 from moving, so as to prevent the battery from short-circuiting and ensure the electrical performance of the battery.

[0048] Combination Figure 3, the width of the blank current collector 15 along the first direction is A, the width of the fixing glue 4 along the first direction is B, A and B satisfy: 0.1≤B / A≤3, for example, the ratio between the width B of the fixing glue 4 and the width A of the blank current collector 15 can be 0.1, 0.2, 0.5, 1, 1.5, 2, 2.5 or 3. Of course, the utility model is not limited to this, and the ratio between the width B of the fixing glue 4 and the width A of the blank current collector 15 can be reasonably selected within the above range according to actual needs. In this way, it is possible to avoid the B / A value being too small. For example, when it is less than 0.1, the width of the fixing glue 4 relative to the blank current collector 15 is smaller, and the coverage of the blank current collector 15 is too small, and the connection reliability with the blank current collector 15 is reduced, and it is impossible to effectively prevent the inner ring structure of the battery cell 100 from moving when the blank current collector 15 is broken. In addition, it is also possible to avoid the B / A value being too large. For example, when it is greater than 3, the width of the fixing glue 4 relative to the blank current collector 15 is too large and overlaps with the pole ear, resulting in an increase in the overall thickness of the battery cell 100, which is not conducive to improving the battery energy density, and the fixing effect of the blank current collector 15 is not significantly improved.

[0049] Combination Figure 1 and Figure 3 , the width of the battery cell 100 along the first direction is C, A and C satisfy: 0.1≤A / C≤0.99, for example, the ratio of the width A of the blank current collector 15 to the width C of the battery cell 100 can be 0.1, 0.2, 0.4, 0.5, 0.6, 0.8, 0.9 or 0.99. Of course, the utility model does not limit this, and the ratio of the width A of the blank current collector 15 to the width C of the battery cell 100 can be reasonably selected within the above range according to actual needs. By controlling the value of A / C within the above range, on the one hand, it is ensured that the blank current collector 15 can stably fix the first pole piece 1 and the winding needle, and on the other hand, the flatness of the battery cell 100 can be adjusted by adjusting the size of the blank current collector 15, thereby ensuring the winding quality.

[0050] In some embodiments, the first current collector 11 includes a paste segment 14 coated with the first active layer 12 on one surface at the start of winding, and the paste segment 14 is adjacent to the blank current collector 15 .

[0051] For example Figure 5 As shown, the first current collector 11 has a first surface and a second surface, and the first surface and the second surface are opposite to each other along the thickness direction. The first active layer 12 may include a first side active layer 12a and a second side active layer 12b, the first side active layer 12a is provided with a first surface, and the second side active layer 12b is provided on the second surface, and when the first electrode sheet 1 is in an unfolded state, the length of the first side active layer 12a is greater than the length of the second side active layer 12b, that is, the first side active layer 12a exceeds a portion of the second side active layer 12b.

[0052] After the winding is completed, the portion of the first-side active layer 12 a that exceeds the second-side active layer 12 b is located on the inner ring structure of the battery cell 100 .

[0053] Combination Figure 3 , and the first pole piece 1 corresponding to the portion of the first-side active layer 12a that exceeds the second-side active layer 12b includes a bending section 13 and a folded paste section 14, the folded paste section 14 is arranged adjacent to the blank current collector 15, and the value range of the width T of the folded paste section 14 in the first direction is: 0mm≤T≤5mm. For example, the width T of the folded paste section 14 can be 0mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm. Of course, the utility model does not limit this. The width T of the folded paste section 14 in the first direction can be reasonably selected within the above range according to actual conditions. In this way, during the coating production process of the first pole piece 1, there is a 0-3mm thinning out-of-control zone at the starting position of the first side active layer 12a of the first pole piece 1. The thinning out-of-control zone is the tailing area generated when the active material is coated. The size of this area is large and difficult to adjust. In this embodiment, the width of the folding paste section 14 is set to 1-5mm, which can avoid the thinning out-of-control zone facing the paste coating of the second pole piece 3, causing the CB value (that is, the ratio of the surface capacity of the first active layer 12 to the surface capacity of the second active layer 32) to be insufficient, thereby avoiding lithium plating and affecting the battery electrical performance.

[0054] Optionally, the winding starting section of the second pole piece 3 is located on the other side of the bending section 13 facing away from the folding paste section 14, and the spacing between the second active layer 32 and the bending section 13 in the first direction is 2mm-5mm. For example, the spacing between the second active layer 32 and the bending section 13 in the first direction is 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm. Of course, the utility model is not limited to this. The spacing between the second active layer 32 and the bending section 13 in the first direction can be reasonably selected within the above range. In this way, the CB value at the junction of the second pole piece 3 and the first pole piece 1 can be guaranteed, thereby avoiding lithium plating and ensuring the electrical performance of the battery.

[0055] Combination Figure 3, the diaphragm 2 includes an extension 22 that extends beyond the blank current collector 15 along the first direction at the start of winding, that is, at the start of winding, the diaphragm 2 extends beyond a portion of the first current collector 11, and the excess portion constitutes the extension 22. The width of the extension 22 in the first direction is D, and A and D satisfy: 0.1≤D / A≤3. For example, the ratio between the width D of the extension 22 and the width A of the blank current collector 15 can be 0.1, 0.2, 0.5, 1, 1.5, 2, 2.5 or 3. Of course, the utility model does not limit this, and the ratio between the width D of the extension 22 and the width A of the blank current collector 15 can be reasonably selected within the above range according to actual needs. In this way, by controlling the value of D / A within the above range, on the one hand, it is ensured that the blank current collector 15 is not exposed, and on the other hand, the flatness of the battery cell 100 can be adjusted by adjusting the size of the extension 22, so as to avoid the overlap of the maximum thickness point of the extension 22 and the battery cell 100, resulting in an increase in the invalid thickness of the battery cell 100, thereby ensuring the winding quality. Here, the maximum thickness point of the battery cell 100 is the bending area at both ends of the battery cell 100 along the first direction, which is formed by winding.

[0056] The diaphragm 2 is formed with a folded portion 21 at the portion that exceeds the first pole piece 1 along the first direction at the winding start section, and the folded portion 21 partially overlaps with the extension portion 22, that is, a part of the folded portion 21 exceeds the blank current collector 15 along the first direction, and the other part is stacked with the blank current collector 15. Optionally, the folded portion 21 can be formed by folding the diaphragm 2 in a Z-shape to form a Z-shaped structure, that is, the folded portion 21 can be formed by folding the portion of the diaphragm 2 that exceeds the blank current collector 15, and the folded portion 21 has a certain thickness. Optionally, the folded portion 21 can be used to wrap the blank current collector 15 to form a wrapping area of ​​the diaphragm 2 for the blank current collector 15.

[0057] Combination Figure 3 , the folding portion 21 is spaced apart from the end of the first active layer 12 along the first direction, and partially overlaps with the blank current collector 15 in the first direction; the width of the folding portion 21 along the first direction is W, and W and A satisfy: 0.03≤W / A≤1. For example, the ratio of W to A can be 0.03, 0.05, 0.08, 0.1, 0.2, 0.5, 0.8 or 1. Of course, the utility model is not limited to this, and the ratio of W to A can be reasonably selected within the above range according to actual needs. In this way, by providing the folding portion 21 and making the ratio of the width of the folding portion 21 to the width of the blank current collector 15 within the above range, on the one hand, it can play a role in fixing the diaphragm 2, and on the other hand, the folding portion 21 can be used to wrap the first pole piece 1 to prevent the blank current collector 15 from being exposed, thereby fixing the empty foil. It can be understood that the larger the width of the blank current collector 15, the larger the width of the folding portion 21 of the diaphragm 2.

[0058] Combination Figure 3 In some embodiments, on the flat surface, the projection of the folded portion 21 is located within the projection of the fixing glue 4. In other words, the folded portion 21 and the fixing glue 4 have an overlapping area in the first direction, and the folded portion 21 has a first endpoint in the first direction close to the winding starting section of the first pole piece 1, and the distance between the first endpoint and the fixing glue 4 in the first direction is D1, and D1 and A satisfy: 0.03≤D1 / A≤2. For example, the ratio of the distance D1 between the first endpoint and the fixing glue 4 to the width A of the blank current collector 15 can be 0.03, 0.06, 0.08, 0.1, 0.2, 0.5, 1, 1.2, 1.5, 1.8 or 2. Of course, the utility model is not limited to this. The ratio of the distance D1 between the first endpoint and the fixing glue 4 to the width A of the blank current collector 15 can be reasonably selected within the above range according to actual needs. In this way, when the blank current collector 15 is broken, the separator 2 and the blank current collector 15 can be better fixed to prevent the inner ring structure of the battery cell 100 from moving, thereby preventing the battery from short circuiting and improving the battery safety.

[0059] In some embodiments, the battery cell 100 may include: a battery cell body 10 and a plurality of tabs. The plurality refers to two or more, preferably three, such as two second tabs and one first tab. The plurality of tabs are disposed at the tab ends of the battery cell body 10. For example, the plurality of tabs may include a second tab and a first tab 101. The second tab may be formed by the second current collector 31 along the second direction (i.e., the length direction of the battery cell 100, such as Figure 1 The first pole tab 101 may be formed by the portion of the first current collector 11 that exceeds the first active layer 12 along the second direction. Each pole tab is provided with an insulating rubber layer 5 on both sides along the thickness direction, and the number of insulating rubber layers 5 on any side of the pole tab may be one, two or more, preferably two. The insulating rubber layer 5 can prevent the pole tab from directly contacting other structures and causing a short circuit.

[0060] Combination Figure 1 , multiple pole ears can be arranged at intervals along the first direction, and an escape gap is jointly defined between the insulating glue layers 5 of two adjacent pole ears close to the starting section of winding in the first direction, and the fixing glue 4 is arranged in the escape gap. In this way, on the one hand, it is possible to avoid interference between the fixing glue 4 and the pole ears, and ensure the normal extension of the pole ears, so as to facilitate connection with other structures of the battery. On the other hand, since the sealing of the battery cell 100 is ensured by melting the fixing glue 4 when packaging the battery cell 100, so that the fixing glue 4 is connected to the PP layer of the aluminum-plastic film, if the fixing glue 4 is connected to the insulating glue layer 5, there is a greater risk of causing poor sealing, and it is difficult to ensure the top-sealing packaging effect. Therefore, staggering the fixing glue 4 and the insulating glue layer 5 is conducive to ensuring the top-sealing packaging effect of the battery cell 100.

[0061] Combination Figure 4 The plurality of tabs may include a first tab 101 as a negative tab, and two second tabs 102 as positive tabs, wherein the two second tabs 102 are a second left tab and a second right tab. The second left tab and the second right tab are respectively located on both sides of the first tab 101 along the first direction, wherein the second left tab is adjacent to the blank current collector 15 in the first direction, and at this time, the fixing glue 4 is in the avoidance gap between the second left tab and the insulating glue layer 5 of the first tab 101.

[0062] Since the fixing glue 4 is bonded to the end surface of the tab of the battery cell 100 and is also connected to the two side surfaces of the battery cell 100 in the thickness direction, the fixing glue 4 has a certain thickness on both sides of the battery cell 100 in the thickness direction. In order to avoid the setting of the fixing glue 4 causing the overall thickness of the battery cell 100 to increase, in this embodiment, two first avoidance grooves 6 are set on the first pole piece 1 oppositely arranged on both sides of each second tab 102. The first avoidance groove 6 can be set on the first active layer 12 on both sides of the second tab, and a first insulating glue layer 5a is set in each first avoidance groove 6. The depth of the first avoidance groove 6 is not less than the sum of the thickness of the first insulating glue layer 5a on the side where the first avoidance groove 6 is located and the thickness of the fixing glue 4, and considering factors such as the manufacturing process, the depth of the first avoidance groove 6 is the sum of the thickness of the first insulating glue layer 5a and the thickness of the fixing glue 4, which can be within the error range of ±5μm. In this way, using the first avoidance groove 6 to accommodate the first insulating glue layer 5a is beneficial to reducing the overall thickness of the battery cell 100. In addition, the depth of the first avoidance groove 6 can also be used to compensate for the increased thickness of the fixing glue 4, thereby avoiding an increase in the thickness of the battery cell 100, which is beneficial to improving the battery energy density.

[0063] Combination Figure 4 In the thickness direction of the battery cell 100, two second avoidance grooves 7 are formed on the second pole pieces 3 arranged opposite to each other on both sides of the first pole lug 101, and a second insulating rubber layer 5b is provided in each second avoidance groove 7. The depth of each second avoidance groove 7 is not less than the thickness of the second insulating rubber layer 5b. In addition, considering factors such as the manufacturing process, the depth of the second avoidance groove 7 is within the error range of ±5μm for the thickness of the insulating rubber layer 5 on the side where the second avoidance groove 7 is located. In this way, it is not only beneficial to reduce the overall thickness of the battery cell 100, but also to avoid removing more of the first active layer 12 to form the second avoidance groove 7, thereby ensuring the battery energy density.

[0064] In some embodiments, the first active layer 12 may include graphite, that is, the graphite material is one of the material components of the first active layer 12. A plurality of recesses 121 are provided on the surface of the first active layer 12. The recesses 121 may be blind holes or linear grooves extending along the width direction of the first current collector 11. The plurality of recesses 121 may be arranged at intervals along the length direction of the first pole piece 1. The recesses 121 are provided to reduce the thickness of the first active layer 12 in the recess 121 region. In this way, the path for ions to be embedded from the surface of the first active layer 12 to the interior is shortened, which can improve the ion migration efficiency and thus improve the battery electrical performance. At the same time, the recesses 121 can also be used to absorb the expansion stress of the first active layer 12 caused by the heat generated during operation.

[0065] In a specific example, the concave portion 121 may be formed by laser marking the surface of the first active layer 12. In this way, the forming process of the concave portion 121 is relatively simple.

[0066] refer to Figure 5 , the depth of the concave portion 121 in the thickness direction of the battery cell 100 is h, and the ratio of the tensile strength of the first current collector 11 in the second direction to the tensile strength in the first direction is e. Among them, e, h and the graphite orientation ratio OI satisfy: 0.01≤e*h / OI≤25, for example, the value of e*h / OI can be 0.01, 0.02, 0.05, 0.08, 1, 2, 5, 10, 12, 15, 18, 20, 22 or 25. Of course, the utility model does not limit this, and the value of e*h / OI can be reasonably selected within the above range according to actual needs. It can be understood that when the laser wire-marking technology is used for the first active layer 12, due to the high laser intensity, a certain impact will be caused to the first current collector 11, which can greatly weaken the tensile strength of the first current collector 11 in the length direction of the battery cell 100. At the same time, the OI value (graphite orientation ratio) of graphite determines the extension of graphite during the charging and discharging process to a certain extent. The smaller the OI value, the smaller the extension of the paste, the smaller the extension stress of the paste on the first current collector 11 during the charging and discharging process, and the less likely the first pole piece 1 is to break. In this embodiment, by controlling the value of e*h / OI within the above range, the first pole piece 1 can be prevented from breaking.

[0067] The battery of the second embodiment of the utility model is described below.

[0068] The battery of this embodiment can be a primary battery or a secondary battery. A primary battery refers to a battery that cannot be recharged and reused after the battery is discharged, and a secondary battery refers to a battery that can be recharged to activate the active material and continue to be used after the battery is discharged. The battery can be any one of a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, and a nickel-hydrogen battery. Of course, the embodiment of the utility model is not limited to this.

[0069] The battery may include: a housing assembly and the battery cell 100 in the above embodiment, the housing assembly defines a receiving cavity, the battery cell 100 is disposed in the housing, and the battery cell 100 may be connected to the positive and negative electrodes on the housing assembly through the tabs.

[0070] The battery of this embodiment can improve the safety of the battery and the electrical performance of the battery by disposing the battery cell 100 of the above embodiment.

[0071] The manufacturing process of the batteries of some embodiments of the present invention is described below.

[0072] Example 1: The battery of this example is manufactured as follows:

[0073] S1, preparation of the second pole piece 3: lithium cobalt oxide, SP, and PVDF are mixed in a mass ratio of 97.6:1.4:1, and NMP is added and stirred evenly to prepare a positive electrode slurry; the positive electrode slurry is coated on the front and back surfaces of the aluminum foil, and after baking and rolling, a second active layer 32 is formed on the front and back surfaces of the aluminum foil to obtain a second pole piece 3, the second pole piece 3 has two slots of fixed size, and an aluminum pole ear is welded in the slot by laser or ultrasonic welding to obtain a second pole piece 3 with two aluminum pole ears;

[0074] S2, preparation of the first electrode sheet 1: two different negative electrode active materials are mixed with SP, CMC-Li, and PAA in a mass ratio of 97:0.4:0.1:2.5, and deionized water is added to prepare a negative electrode slurry; the two different negative electrode slurries are coated on the front and back surfaces of the carbon-coated copper foil (the transverse tensile strength of the copper foil used is 1: the longitudinal tensile strength is 1) to form a double-sided paste-coated first electrode sheet 1, wherein the thickness ratio of the upper paste layer to the lower paste layer is 0.25, wherein the width A of the blank current collector 15 is 12 mm, and after baking and rolling, The first active layer 12 is formed on the front and back surfaces of the carbon-coated copper foil, and a linear concave portion 121 is punched on the surface of the negative electrode active material layer on each side by laser (the concave portion 121 does not penetrate the first active layer 12), the distance between two adjacent concave portions 121 is ΔL=1.2 mm, the width of the concave portion 121 is L=80 μm, and the depth of the concave portion is h=18 μm, so as to obtain a first pole piece 1, and the OI value of the mixture of the upper graphite layer and the lower graphite layer is 20; a certain position of the first pole piece 1 has a slot of fixed size, and the copper-plated nickel pole ear is welded in this slot by laser or ultrasonic welding;

[0075] S3: After the second pole piece 3 and the first pole piece 1 are cut and sliced, they are wound with the separator 2 to obtain a wound battery cell 100 with a width of 68 mm and a thickness of 5.151 mm. The width B of the fixing glue 4 of the battery cell 100 is 5 mm, and the fixing glue 4 overlaps with the blank current collector 15 in the first direction. The fixing glue 4 is located between the first positive electrode ear 102 and the negative electrode ear 101, wherein the width of the avoidance gap between the first positive electrode ear 102 and the negative electrode ear 101 is 25 mm; the separator 2 adopts a "Z"-shaped folding method at the starting section of the winding, the distance between the starting position of the folding part 21 and the fixing glue 4 is D1=2 mm, the width of the folding part 21 is W=4 mm, and the size of the separator 2 super-negative empty foil is D=15 mm;

[0076] Step 4: After packaging, baking, liquid injection, formation, secondary sealing, sorting and OCV, a lithium-ion battery is obtained. The electrolyte is a commercially available conventional electrolyte, and the lithium salt is LiFP6.

[0077] Embodiment 2 is different from Embodiment 1 in that the width of the hollow foil is A=68 mm;

[0078] Embodiment 3 is different from Embodiment 1 in that the width of the hollow foil is A=68 mm, and the distance between the first end point of the folded portion 21 of the diaphragm 2 and the fixing glue 4 is D1=3 mm;

[0079] Embodiment 4 is different from Embodiment 1 in that the width of the hollow foil is A=60 mm, and the width of the folded portion 21 of the separator 2 is W=1.5 mm;

[0080] Embodiment 5 is different from Embodiment 1 in that the width A of the blank current collector 15 is 60 mm;

[0081] Embodiment 6 is different from Embodiment 1 in that the width A of the blank current collector 15 is 60 mm, and the width D of the extension portion 22 of the separator 2 is 5 mm;

[0082] Embodiment 7 is different from Embodiment 1 in that the width A of the blank current collector 15 is 6 mm, and the battery cell 100 is not provided with a fixing glue 4;

[0083] Embodiment 8 is different from Embodiment 1 in that the width A of the blank current collector 15 is 60 mm;

[0084] Embodiment 9 is different from Embodiment 1 in that the width A of the blank current collector 15 is 60 mm, and the width B of the fixing glue 4 is 20 mm;

[0085] Embodiment 10 is different from Embodiment 1 in that the width A of the blank current collector 15 is 60 mm, and the width B of the fixing glue 4 is 18 mm;

[0086] Embodiment 11 is different from Embodiment 1 in that the width of the folded portion 21 of the separator 2 is W=8 mm, and the width of the blank current collector 15 is A=8 mm;

[0087] Embodiment 12 is different from Embodiment 1 in that the width of the folded portion 21 of the diaphragm 2 is W=9 mm;

[0088] Embodiment 13 is different from Embodiment 1 in that the width D of the extension portion 22 of the separator 2 is 40 mm, and the width A of the blank current collector 15 is 12 mm;

[0089] Embodiment 14 is different from Embodiment 1 in that the width of the folded portion 21 of the separator 2 is W=2 mm, and the width of the blank current collector 15 is A=12 mm;

[0090] Embodiment 15 is different from Embodiment 1 in that the depth of the concave portion 121 is h=0 μm;

[0091] Example 16 is different from Example 1 in that the depth of the concave portion 121 is h=2 μm, OI=30, and the transverse tensile strength of the copper foil is e=0.3.

[0092] Example 17 is different from Example 1 in that the depth of the concave portion 121 is h=45 μm, OI=3, and the transverse tensile strength of the copper foil is e=2.

[0093] Example 18 is different from Example 1 in that the depth of the recess 121 is h=35 μm, OI=3, and the transverse tensile strength of the copper foil is e=2.

[0094] The above embodiments are tested for the following parameters:

[0095] Test 1: Pole piece OI value test, after disassembling the finished battery cell 100, take the first pole piece 1 with complete paste coating, soak it in DMC for more than 2 hours, and then test WRD after standing in a room with a dew point of ≤-35° for more than 2 hours. The orientation of the graphite electrode is described by the ratio of the (002) or (004) diffraction peak intensity (or integrated area) to the (110) emission peak intensity (or integrated area), OI=I(002) / (110) or OI=I(004) / (110);

[0096] Test 2: Current collector tensile strength, after disassembling the finished battery cell 100, soak the first pole piece 1 in DMC for more than 2 hours, let it stand in a room with a dew point of ≤-35° for more than 2 hours, soak it in deionized water until the paste is completely removed, let it stand in a room with a dew point of ≤-35° to dry the first current collector 11, use a tool to cut the first current collector 11 into samples with a width of 15 mm and a length of more than 50 mm, use a WD-D3 electronic universal testing machine (with a precision of 0.5 level and an accuracy of ±1% of the indicated value), set the gauge length to 50 mm and the speed to 50 mm / min, and perform a tensile strength test;

[0097] Test 3: The depth of the concave portion 121 is measured by scanning the surface topography using a 3D profile microscope;

[0098] Test 4: voltage drop. The batteries of each embodiment are charged to 3.95V using 0.2C constant current and constant voltage, with a cut-off value of 0.02C. After standing in a constant temperature room at 45°C for 48 to 60 hours, the batteries are taken out and the voltage V1 is tested after standing in a constant temperature room at 25°C for 24 hours. After standing for another 48 to 72 hours, the voltage V2 is tested. Voltage drop = (V2-V1) / standing time.

[0099] The parameters of the related structures of the above embodiments are as follows:

[0100]

[0101] The inventor of the present application has respectively conducted the above-mentioned tests 1 to 4 for the batteries corresponding to the above-mentioned embodiments, and obtained the test results of the relevant parameters of the batteries of the above-mentioned embodiments. The test structures of the above-mentioned embodiments are as follows:

[0102]

[0103] It can be seen from the combination of Examples 2-3 that the blank current collector 15 of the first pole piece 1 is relatively long, and its movable range is relatively wide, and the enclosed area of ​​the fixing glue 4 is correspondingly relatively wide, wherein the area corresponding to the distance between the starting point of the folded portion 21 of the diaphragm 2 and the fixing glue 4 is the second enclosed area other than the enclosed area of ​​the fixing glue 4 itself, and the larger the enclosed area, the better, and when D1 / A≤0.03, the battery cell 100 has a relatively obvious voltage drop;

[0104] It can be seen from the combination of Examples 3a-3b that the blank current collector 15 is shorter in size and has a narrower range of movement. Accordingly, the fixing glue 4 only needs a smaller wrapped closed area. At this time, if the second closed area is excessive, when D1 / A>2, the separator 2 inside the battery cell 100 reaches the area where the pole ear is located and overlaps with the pole ear, which increases the thickness of the battery cell 100 and reduces the energy density of the battery cell 100.

[0105] In combination with Examples 1, 3, and 8, it can be seen that when the ratio of the width A of the blank current collector 15 to the width C of the battery cell is 0.9<A / C, the width of the blank current collector 15 is relatively large, exceeding the innermost folded width of the battery cell 100 (i.e., the width of the inner circle of the battery cell 100), and the blank current collector 15 needs to be bent a second time. At this time, the thickness of the battery cell 100 needs to be increased by an additional amount compared to the thickness of the battery cell 100 when 0.1≤A / C≤0.99, resulting in a loss of energy density of the battery cell 100; when A / C<0.1, due to the small width of the blank current collector 15, the negative electrode sheet cannot be effectively controlled to be on the winding needle, resulting in the blank current collector 15 folded inwardly of the battery cell 100 being wrinkled or folded, increasing the probability of short circuit of the battery cell 100, resulting in an increase in the average voltage drop of the battery cell 100;

[0106] In combination with Examples 1, 4, 11, and 12, it can be seen that the diaphragm 2 forms a complete wrapping area for the blank current collector 15 through the folding portion 21. The longer the size of the blank current collector 15, the width of the folding portion 21 of the diaphragm 2 needs to be increased accordingly to prevent the folding portion 21 from opening and failing due to force on the wrapping area of ​​the blank current collector 15. Among them, when W / A is less than 0.03, the width of the folding portion 21 of the diaphragm 2 is insufficient, the wrapping area fails, and an open area is formed, resulting in an increase in the voltage drop of the battery cell 100; when W / A is greater than 1, the width of the folding portion 21 of the diaphragm 2 is relatively excessive, the diaphragm 2 is too long, and it coincides with the maximum thickness point of the battery cell 100, resulting in an increase in the invalid thickness and sacrificing the energy density of the battery cell 100;

[0107] It can be seen from Examples 1, 5, 6, and 13 that when D / A>3, the width of the extension portion 22 of the diaphragm 2 is relatively large, coinciding with the maximum thickness point of the battery cell 100, increasing the ineffective thickness of the battery cell 100 and sacrificing the energy density of the battery cell 100; when D / A<0.1, the diaphragm 2 cannot complete the wrapping and sealing of the negative electrode sheet, and the battery cell 100 has a significant voltage drop;

[0108] It can be seen from Examples 15-18 that when e*h / OI>25, a stronger laser intensity is used to form a deeper recess 121. During the process of forming the recess 121, the first active layer 12, i.e., the negative electrode paste layer, falls off into the recess 121 and cannot be removed, which may cause a short circuit inside the battery cell 100 and a significant voltage drop in the battery cell 100. When e*h / OI<0.01, because the depth of the recess 121 is shallow or the laser wire-punching technology is not used to form the recess 121, the micro short circuit caused by dust formed by the laser wire-punching can be significantly eliminated, and the voltage drop of the battery cell 100 is improved. However, at this time, the dynamic performance of one side of the negative electrode sheet is reduced. Under the same charge and discharge performance requirements, it is necessary to increase the length of the negative electrode sheet to reduce the negative electrode surface density and improve the dynamic performance, which may cause the overall thickening of the battery cell 100 and reduce the energy density.

[0109] In addition, in combination with Table 1 and Table 2, by comparing Example 7 with other embodiments, it can be seen that since Example 7 does not have a fixing glue 4 and the width of the blank current collector 15 is small, the battery may have a short circuit problem caused by the movement of the internal structure, resulting in a large battery voltage drop; by comparing Example 9 and Example 10 with other embodiments, since the width of the fixing glue 4 is too large, the fixing glue 4 may overlap with the tab or the insulating glue layer 5 on both sides of the tab in the first direction, resulting in poor top sealing of the battery; by comparing Example 1 with Examples 2-6, it can be seen that by increasing the width of the blank current collector 15 and reducing the D / A value, the stability of the negative electrode sheet at the starting section of the winding can be increased, which is beneficial to reducing the battery voltage drop and improving the battery electrical performance; by comparing Example 15 with other embodiments, since the recess 121 on the first active layer 12 is eliminated, the ion dynamics performance will be affected, so it is necessary to increase the length of the first pole sheet 1 and reduce the surface density to make the battery electrical performance meet the requirements; through implementation 17, it can be seen that when the depth of the recess of the first active layer 12 is too large, it is easy to cause powder falling.

[0110] In summary, the inventors of the present application have jointly regulated multiple factors, including the ratio A / C of the width of the blank current collector 15 on the negative electrode sheet (i.e., the first electrode sheet 1) of the battery cell 100 to the width of the battery cell 100, the ratio D / A of the width of the extension portion 22 of the diaphragm 2 to the width of the blank current collector 15, the ratio W / A of the width of the folded portion 21 of the diaphragm 2 to the width of the blank current collector 15, the ratio D1 / A of the distance between the starting point of the folded portion 21 and the fixing glue 4 and the width of the blank current collector 15, as well as the e*h / OI value, the thickness of the battery cell 100 and the depth of the recess 121 on the first active layer 12. The battery regulated based on the above multiple factors can significantly reduce the voltage drop, improve the battery energy density, and have better electrical performance.

[0111] The following describes an electrical device according to an embodiment of the third aspect of the utility model.

[0112] The power-consuming device of this embodiment may be a mobile phone, a tablet computer, a laptop computer, a new energy vehicle, a smart watch, a communication base station, etc. Specifically, the power-consuming device may include: a device body and the battery in the above embodiment. The device body has a battery compartment, the battery may be arranged in the battery compartment, and the battery is electrically connected to the device body.

[0113] According to the electric device of the embodiment of the utility model, by providing the battery in the above embodiment, the battery can more reliably supply power to the electric device, which is beneficial to improving the user experience.

[0114] The various embodiments or implementation methods in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referenced to each other.

[0115] It should be noted that the embodiments represented by "one embodiment", "an embodiment", "an exemplary embodiment", "some embodiments", etc. mentioned in the specification may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when describing specific features, structures or characteristics in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such features, structures or characteristics in conjunction with other embodiments that are explicitly or not explicitly described.

[0116] In general, terms should be understood, at least in part, by the context in which they are used. For example, the term "one or more" as used herein may be used to describe any feature, structure, or characteristic in a singular sense, or may be used to describe a combination of features, structures, or characteristics in a plural sense, depending, at least in part, on the context. Similarly, terms such as "a," "an," or "the" may also be understood to convey singular usage or to convey plural usage, depending, at least in part, on the context.

[0117] It should be easily understood that “on,” “above,” and “over” in the present disclosure should be interpreted in the broadest manner, so that “on” not only means “directly on something,” but also includes the meaning of “on something” with intervening features or layers therebetween, and “above” or “over” not only includes the meaning of “above” or “over,” but also may include the meaning of “above” or “over something” with no intervening features or layers therebetween (i.e., directly on something).

[0118] Additionally, cavity-relative terms, such as "below," "below," "beneath," "above," "above," etc., may be used herein for ease of description to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Cavity-relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. The device may have other orientations (rotated 90 degrees or at other orientations), and the cavity-relative descriptors used herein may likewise be interpreted accordingly.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A battery cell, characterized in that: It comprises a first pole piece, a diaphragm and a second pole piece which are sequentially stacked and wound, wherein the first pole piece and the second pole piece have opposite polarities; The first pole piece includes a first current collector and a first active layer coated on the first current collector, the first pole piece includes a winding start section located inside, and the first current collector includes a blank current collector at the winding start section where the first active layer is not coated; The battery cell also includes a fixing glue, which is bonded and fixed to the end surface of the battery cell's pole lug and the flat surfaces on both sides of the battery cell. On the flat surfaces, the projection of one end of the blank current collector away from the first active layer is located within the projection of the fixing glue.

2. The battery cell according to claim 1, characterized in that: The width of the blank current collector along the first direction is A, the width of the fixing glue along the first direction is B, and A and B satisfy: 0.1≤B / A≤3.

3. The battery cell according to claim 1, characterized in that: The width of the blank current collector along the first direction is A; A width of the battery cell along the first direction is C, and A and C satisfy: 0.1≤A / C≤0.

99.

4. The battery cell according to claim 1, characterized in that: The first current collector includes a folding paste section with the first active layer coated on one surface at the winding starting section, the folding paste section is adjacent to the blank current collector, wherein the width T of the folding paste section in the first direction ranges from 0mm<T≤5mm.

5. The battery cell according to claim 1, characterized in that: The width of the blank current collector along the first direction is A; The separator comprises an extension portion extending beyond the blank current collector along the first direction at the winding start section, the extension portion has a width D in the first direction, and A and D satisfy: 0.1≤D / A≤3; and / or At least part of the separator is Z-folded at the winding start section along the first direction beyond the part of the first pole piece to form a folded portion, and the folded portion overlaps with the projection of the blank current collector on the flat surface; The width of the folded portion along the first direction is W, and W and A satisfy: 0.03≤W / A≤1.

6. The battery cell according to claim 5, characterized in that: On the flat surface, the projection of the folded portion is located within the projection of the fixing glue, and, The folding portion has a first end point close to the winding start section of the first pole piece in the first direction, and the first end point is spaced apart from the fixing glue in the first direction by D1, and D1 and A satisfy: 0.03≤D1 / A≤2.

7. The battery cell according to claim 1, characterized in that: The battery core further comprises a plurality of tabs extending from the end surface of the tab, and each tab is provided with an insulating rubber layer on both sides along the thickness direction; The plurality of pole tabs are arranged at intervals along the first direction, and an escape gap is defined between the insulating adhesive layers of two adjacent pole tabs close to the winding start section, and the fixing adhesive is located in the escape gap.

8. The battery cell according to claim 1, characterized in that: At least one second pole lug is provided on the second pole sheet, and two first avoidance grooves are formed on the first pole sheet arranged opposite to each second pole lug on both sides along the thickness direction of the battery cell, and a first insulating glue layer is provided in each of the first avoidance grooves, wherein the depth of each of the first avoidance grooves is not less than the sum of the thickness of the first insulating glue layer and the thickness of the fixing glue; and / or, A first pole ear is provided on the first pole piece, and two second avoidance grooves are formed on the second pole piece arranged opposite to the first pole ear on both sides along the thickness direction of the battery cell, and a second insulating rubber layer is provided in each of the second avoidance grooves, wherein the depth of each of the second avoidance grooves is not less than the thickness of the second insulating rubber layer.

9. The battery cell according to claim 1, characterized in that: The first active layer comprises graphite, A plurality of recesses are provided on the surface of the first active layer, and the plurality of recesses are arranged at intervals along the length direction of the first pole piece; The depth of the recess in the thickness direction of the battery cell is h, the ratio of the tensile strength of the first current collector in the second direction to the tensile strength in the first direction is e, and e, h and the graphite orientation ratio OI satisfy: 0.01≤e*h / OI≤25.

10. A battery, characterized in that: include: a housing assembly, wherein the housing assembly defines a receiving cavity; The battery cell according to any one of claims 1 to 9, wherein the battery cell is arranged in the accommodating cavity.

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